source
stringlengths 642
3.44k
| target
stringlengths 24
19.9k
| lan
stringclasses 23
values |
|---|---|---|
The Doppler dipole signal dominates the cosmic microwave background (CMB) anisotropy maps obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) mission, and plays a key role throughout the data processing. Previously, we discovered a timing asynchronism of -25.6ms between the timestamps of the spacecraft attitude and radiometer output in the original raw WMAP time-ordered data (TOD), which, if not corrected in following data processing, would generate an artificial quadrupole component (l=2) in recovered CMB maps (Liu, Xiong & Li 2010). Recently, Roukema (2010b) proves that there does exist a timing-offset-induced error corresponding to about -25.6ms in the WMAP calibrated TOD by studying the fluctuation variance per pixel in the temperature map recovered from the TOD as a function of assumed timing-offset. Here, we find evidence directly in the WMAP TOD for such an uncorrected timing error, possibly occurred in calculating the Doppler dipole signal during the WMAP team's TOD data processing. The amplitude is highly significant and is consistent with previous work. We also show that the uncorrected timing-offset can lead the WMAP CMB quadrupole to be substantially overestimated.
|
ドップラー双極信号は、ウィルキンソン宇宙背景放射異方性探査機（WMAP）ミッションによって得られた宇宙マイクロ波背景放射（CMB）異方性マップにおいて支配的であり、データ処理全体を通じて重要な役割を果たしている。以前、我々は、オリジナルの生のWMAP時系列データ（TOD）における宇宙船の姿勢データと放射計出力のタイムスタンプ間に-25.6ミリ秒のタイミング非同期が存在することを発見した。このずれが、その後のデータ処理で補正されない場合、得られたCMBマップに人工的な四極子成分（l=2）を生じることになる（Liu, Xiong & Li 2010）。最近、Roukema（2010b）は、仮定されるタイミングずれの関数としてTODから再構成された温度マップのピクセルごとの変動分散を調査することで、WMAPの較正済みTODに約-25.6ミリ秒のタイミングずれに起因する誤差が実際に存在することを証明した。本研究では、WMAPチームによるTODデータ処理中にドップラー双極信号の計算時に生じた可能性のある、補正されていないタイミング誤差の存在について、WMAPのTODデータそのものに直接的な証拠を見出した。その振幅は非常に有意であり、先行研究の結果と一致している。また、補正されていないタイミングずれが、WMAPのCMB四極子を大きく過大評価させることにつながることも示した。
|
ja
|
In this work, we propose to utilize discrete graph Ricci flow to alter network entropy through feedback control. Given such feedback input can reverse entropic changes, we adapt the moniker of Maxwells Demon to motivate our approach. In particular, it has been recently shown that Ricci curvature from geometry is intrinsically connected to Boltzmann entropy as well as functional robustness of networks or the ability to maintain functionality in the presence of random fluctuations. From this, the discrete Ricci flow provides a natural avenue to rewire a particular networks underlying geometry to improve throughout and resilience. Due to the real-world setting for which one may be interested in imposing nonlinear constraints amongst particular agents to understand the network dynamic evolution, controlling discrete Ricci flow may be necessary (e.g., we may seek to understand the entropic dynamics and curvature flow between two networks as opposed to solely curvature shrinkage). In turn, this can be formulated as a natural control problem for which we employ feedback control towards discrete Ricci-based flow and show that under certain discretization, namely Ollivier-Ricci curvature, one can show stability via Lyapunov analysis. We conclude with preliminary results with remarks on potential applications that will be a subject of future work.
|
本研究では、離散的グラフリッチフローを用いてフィードバック制御を通じてネットワークエントロピーを変化させることを提案する。このようなフィードバック入力がエントロピー変化を逆転させ得ることから、我々のアプローチの動機付けとして「マクスウェルの悪魔」という呼称を採用する。特に最近、幾何学におけるリッチ曲率がボルツマンエントロピーおよびネットワークの機能的ロバスト性、すなわちランダムな変動が存在する中でも機能を維持する能力と本質的に関連していることが示されている。これにより、離散的リッチフローは、特定のネットワークの基礎的幾何構造を再構成し、スループットとレジリエンスを向上させる自然な手段を提供する。特定のエージェント間で非線形制約を課してネットワークの動的進化を理解しようとする現実的な状況では、離散的リッチフローを制御することが必要となる場合がある（例えば、単に曲率の収縮だけでなく、2つのネットワーク間のエントロピー動態および曲率フローを理解しようとする場合など）。この問題は自然な制御問題として定式化でき、我々は離散的リッチに基づくフローに対してフィードバック制御を適用し、特にオリヴィエ・リッチ曲率というある種の離散化のもとで、リアプノフ解析により安定性を示すことができる。最後に、今後の研究の対象となる潜在的応用に関する考察とともに、予備的結果を提示する。
|
ja
|
Understanding and interacting with everyday physical scenes requires rich knowledge about the structure of the world, represented either implicitly in a value or policy function, or explicitly in a transition model. Here we introduce a new class of learnable models--based on graph networks--which implement an inductive bias for object- and relation-centric representations of complex, dynamical systems. Our results show that as a forward model, our approach supports accurate predictions from real and simulated data, and surprisingly strong and efficient generalization, across eight distinct physical systems which we varied parametrically and structurally. We also found that our inference model can perform system identification. Our models are also differentiable, and support online planning via gradient-based trajectory optimization, as well as offline policy optimization. Our framework offers new opportunities for harnessing and exploiting rich knowledge about the world, and takes a key step toward building machines with more human-like representations of the world.
|
ການເຂົ້າໃຈ ແລະ ການມີສ່ວນຮ່ວມກັບສະຖານະການທາງດ້ານຮ່າງກາຍໃນຊີວິດປະຈຳວັນ ຕ້ອງການຄວາມຮູ້ທີ່ເລິກເຊິ່ງກ່ຽວກັບໂຄງສ້າງຂອງໂລກ, ທີ່ຖືກສະແດງອອກບັງຄັບໃນຮູບແບບຂອງຟັງຊັ່ນຄ່າ ຫຼື ນະໂຍບາຍ, ຫຼື ສະແດງອອກຢ່າງຊັດເຈນໃນແບບຈຳລອງການຖ່າຍໂອນ. ໃນບົດນີ້ ພວກເຮົານຳສະເໜີຊັ້ນຂອງແບບຈຳລອງທີ່ສາມາດຮຽນຮູ້ໄດ້ໃໝ່ ໂດຍອີງໃສ່ເຄືອຂ່າຍກຼາຟ (graph networks) ເຊິ່ງຈັດຕັ້ງປະຕິບັດການເບື່ອງເບິ່ງແບບອຸປະນິໄສສຳລັບການສະແດງຜົນທີ່ກ້ຽວຂ້ອງກັບວັດຖຸ ແລະ ຄວາມສຳພັນຂອງລະບົບທີ່ຊັບຊ້ອນ ແລະ ໄດ້ນາມິກ. ຜົນໄດ້ຮັບຂອງພວກເຮົາສະແດງໃຫ້ເຫັນວ່າ ເປັນແບບຈຳລອງການເຄື່ອນໄປຂ້າງໜ້າ, ວິທີການຂອງພວກເຮົາສະໜັບສະໜູນການຄາດຄະເນທີ່ຖືກຕ້ອງຈາກຂໍ້ມູນຈິງ ແລະ ຂໍ້ມູນທີ່ຈຳລອງ, ພ້ອມທັງການທົດລອງທົ່ວໄປທີ່ແຂງແຮງ ແລະ ມີປະສິດທິພາບສູງຢ່າງຫນ້າປະຫລາດໃຈ, ທົ່ວລະບົບດ້ານຮ່າງກາຍແຕກຕ່າງກັນ 8 ລະບົບ ທີ່ພວກເຮົາປ່ຽນແປງແບບພາລາມິເຕີ ແລະ ໂຄງສ້າງ. ພວກເຮົາຍັງພົບວ່າ ແບບຈຳລອງການສົມມຸດຂອງພວກເຮົາສາມາດປະຕິບັດການຈຳແນກລະບົບໄດ້. ແບບຈຳລອງຂອງພວກເຮົາຍັງສາມາດແຍກຕ່າງຫາກໄດ້, ແລະ ສະໜັບສະໜູນການວາງແຜນແບບອອນໄລນ໌ຜ່ານການເພີ່ມປະສິດທິພາບເສັ້ນທາງທີ່ອີງໃສ່ເສັ້ນຊື່, ພ້ອມທັງການເພີ່ມປະສິດທິພາບນະໂຍບາຍແບບອອຟໄລນ໌. ໂຄງຮ່າງຂອງພວກເຮົາສະເໜີໂອກາດໃໝ່ໆໃນການນຳໃຊ້ ແລະ ສົ່ງເສີມຄວາມຮູ້ທີ່ເລິກເຊິ່ງກ່ຽວກັບໂລກ, ແລະ ເດີນກ້າວສຳຄັນໄປສູ່ການສ້າງເຄື່ອງຈັກທີ່ມີການສະແດງຜົນຂອງໂລກຄືກັບຄົນ.
|
lo
|
We discuss the prospects for detecting supersymmetric particles in variants of the minimal supersymmetric extension of the Standard Model (MSSM), in light of laboratory and cosmological constraints. We first assume that the lightest supersymmetric particle (LSP) is the lightest neutralino chi, and present scatter plots of the masses of the two lightest visible supersymmetric particles when the input scalar and gaugino masses are constrained to be universal (CMSSM), when the input Higgs scalar masses are non-universal (NUHM), and when the squark and slepton masses are also non-universal and the MSSM is regarded as a low-energy effective field theory valid up to the GUT scale (LEEST) or just up to 10 TeV (LEEST10). We then present similar plots in various scenarios when the LSP is the gravitino. We compare the prospects for detecting supersymmetry at linear colliders (LCs) of various energies, at the LHC, and as astrophysical dark matter. We find that, whilst a LC with a centre-of-mass energy E_{CM} <= 1000 GeV has some chance of discovering the lightest and next-to-lightest visible supersymmetric particles, E_{CM} >= 3000 GeV would be required to `guarantee' finding supersymmetry in the neutralino LSP scenarios studied, and an even higher E_{CM} might be required in certain gravitino dark matter scenarios. Direct dark matter experiments could explore part of the low-mass neutralino LSP region, but would not reveal all the models accessible to a low-energy LC.
|
Мы обсуждаем перспективы обнаружения суперсимметричных частиц в различных вариантах минимального суперсимметричного расширения Стандартной модели (МССМ) с учётом лабораторных и космологических ограничений. Сначала мы предполагаем, что наименее массивной суперсимметричной частицей (НМСП) является самый лёгкий нейтральныйino χ, и приводим диаграммы рассеяния масс двух самых лёгких видимых суперсимметричных частиц в случаях, когда входящие скалярные и гауджиновые массы предполагаются универсальными (СМССМ), когда входящие массы хиггсовских скалярных частиц неуниверсальны (НУХМ), а также когда массы скварков и сляптонов также неуниверсальны и МССМ рассматривается как эффективная теория поля низких энергий, применимая вплоть до масштаба объединения (GUT) (ЛЕЕСТ) или только до 10 ТэВ (ЛЕЕСТ10). Затем мы приводим аналогичные графики для различных сценариев, в которых НМСП является гравитино. Мы сравниваем перспективы обнаружения суперсимметрии на линейных коллайдерах (ЛК) различной энергии, на БАК и в астрофизических экспериментах по поиску тёмной материи. Мы приходим к выводу, что хотя линейный коллайдер с энергией в центре масс E_{CM} <= 1000 ГэВ имеет определённые шансы обнаружить самую лёгкую и вторую по лёгкости видимые суперсимметричные частицы, для «гарантированного» обнаружения суперсимметрии в рассмотренных сценариях с нейтральным НМСП потребуется E_{CM} >= 3000 ГэВ, а в некоторых сценариях тёмной материи с гравитино может потребоваться ещё более высокая энергия. Прямые эксперименты по поиску тёмной материи смогут исследовать часть области с низкой массой нейтрального НМСП, но не позволят обнаружить все модели, доступные низкоэнергетическому линейному коллайдеру.
|
ru
|
The routing and wavelength assignment with protection is an important problem in telecommunications. Given an optical network and incoming connection requests, a commonly studied variant of the problem aims to grant maximum number of requests by assigning lightpaths at minimum network resource usage level, while ensuring the provided services remain functional in case of a single-link failure through dedicated path protection. We consider a practically relevant version where alternative lightpaths for requests are assumed to be given as a precomputed set, and show that it is NP-hard. We formulate the problem as an integer programming (IP) model, and also use it as a foundation to develop a novel quadratic unconstrained binary optimization (QUBO) model, which can be both directly solved by a state-of-the-art solver like GUROBI. We present necessary and sufficient conditions on objective function parameters to prioritize request granting objective over wavelength-link usage for both models, and a sufficient condition to ensure the exactness of the QUBO model. Moreover, we implement a problem-specific branch-and-cut algorithm for the IP model, and employ a new quantum-inspired technology, Digital Annealer (DA), for the QUBO model. We conduct computational experiments on a large suite of instances that are hard to optimally solve in order to assess the efficiency and efficacy of all of these approaches as well as a problem-specific heuristic. The results show that the emerging technology DA outperforms the considered established techniques coupled with GUROBI, in finding mostly significantly better or as good solutions in only two minutes compared to two hours of run time, whereas the problem-specific heuristic fails to be competitive.
|
تُعد مشكلة تعيين التوجيه والموجه مهمة في مجال الاتصالات. بالنظر إلى شبكة بصرية وطلبات اتصال واردة، تهدف إحدى الصيغ المدروسة بشكل شائع من هذه المشكلة إلى قبول أكبر عدد ممكن من الطلبات عن طريق تعيين مسارات ضوئية بأقل مستوى ممكن من استهلاك موارد الشبكة، مع ضمان استمرار الخدمات المقدمة في العمل في حالة حدوث عطل في أحد الاتصالات عبر حماية المسار المخصصة. نحن نتناول نسخة ذات صلة عملية، حيث يُفترض أن المسارات الضوئية البديلة للطلبات معطاة على شكل مجموعة محسوبة مسبقًا، ونُثبت أن هذه المسألة تنتمي إلى صنف المسائل NP الصعبة. نصوغ المشكلة على شكل نموذج برمجة صحيحة (IP)، ونستخدمه أيضًا كأساس لتطوير نموذج جديد من نوع التحسين الثنائي غير المقيد التربيعي (QUBO)، والذي يمكن حله مباشرة بواسطة برنامج متقدم مثل GUROBI. نقدّم شروطًا ضرورية وكافية على معاملات دالة الهدف لجعل هدف قبول الطلبات أولوية على هدف استخدام الموجات-الوصلات في كلا النموذجين، وشرطًا كافيًا لضمان دقة نموذج QUBO. علاوة على ذلك، نُنفّذ خوارزمية فرعية وقطع مخصصة للنموذج IP، ونستخدم تقنية جديدة مستوحاة من الحوسبة الكمية، تُعرف باسم المُخفِّف الرقمي (DA)، للنموذج QUBO. نُجري تجارب حسابية على مجموعة كبيرة من الحالات الصعبة الحل الأمثل من أجل تقييم كفاءة وفعالية جميع هذه الأساليب بالإضافة إلى خوارزمية حدسية مخصصة للمشكلة. تُظهر النتائج أن التقنية الناشئة DA تتفوق على التقنيات التقليدية المستخدمة مع GUROBI، حيث تُحقق حلولًا أفضل بشكل ملحوظ أو مماثلة من حيث الجودة في دقيقتين فقط مقارنة بساعتين من وقت التشغيل، في حين تفشل الخوارزمية الحدسية الخاصة بالمسألة في المنافسة.
|
ar
|
The atmospheres of small, potentially rocky exoplanets are expected to cover a diverse range in composition and mass. Studying such objects therefore requires flexible and wide-ranging modeling capabilities. We present in this work the essential development steps that lead to our flexible radiative transfer module, REDFOX, and validate REDFOX for the Solar system planets Earth, Venus and Mars, as well as for steam atmospheres. REDFOX is a k-distribution model using the correlated-k approach with random overlap method for the calculation of opacities used in the $\delta$-two-stream approximation for radiative transfer. Opacity contributions from Rayleigh scattering, UV / visible cross sections and continua can be added selectively. With the improved capabilities of our new model, we calculate various atmospheric scenarios for K2-18b, a super-Earth / sub-Neptune with $\sim$8 M$_\oplus$ orbiting in the temperate zone around an M-star, with recently observed H$_2$O spectral features in the infrared. We model Earth-like, Venus-like, as well as H$_2$-He primary atmospheres of different Solar metallicity and show resulting climates and spectral characteristics, compared to observed data. Our results suggest that K2-18b has an H$_2$-He atmosphere with limited amounts of H$_2$O and CH$_4$. Results do not support the possibility of K2-18b having a water reservoir directly exposed to the atmosphere, which would reduce atmospheric scale heights, hence too the amplitudes of spectral features inconsistent with the observations. We also performed tests for H$_2$-He atmospheres up to 50 times Solar metallicity, all compatible with the observations.
|
Các khí quyển của các ngoại hành tinh nhỏ, có khả năng là loại đá, được dự đoán sẽ đa dạng về thành phần và khối lượng. Do đó, việc nghiên cứu các vật thể như vậy đòi hỏi các khả năng mô hình hóa linh hoạt và toàn diện. Trong nghiên cứu này, chúng tôi trình bày các bước phát triển cơ bản dẫn đến mô-đun truyền bức xạ linh hoạt của chúng tôi, REDFOX, và xác thực REDFOX đối với các hành tinh trong Hệ Mặt Trời là Trái Đất, Sao Kim và Sao Hỏa, cũng như đối với các khí quyển hơi nước. REDFOX là một mô hình phân bố-k sử dụng phương pháp k-tương quan kết hợp với phương pháp chồng lấp ngẫu nhiên để tính toán độ mờ đục được dùng trong phép xấp xỉ hai luồng δ cho quá trình truyền bức xạ. Các đóng góp độ mờ đục từ tán xạ Rayleigh, các tiết diện và nền ở vùng tử ngoại / khả kiến có thể được thêm vào một cách chọn lọc. Với các khả năng cải tiến của mô hình mới, chúng tôi tính toán nhiều kịch bản khí quyển khác nhau cho K2-18b, một siêu Trái Đất / hành tinh con của Sao Hải Vương có khối lượng khoảng 8 M⊕, quay quanh một ngôi sao kiểu M trong vùng ôn hòa, với các đặc trưng quang phổ H₂O gần đây được quan sát thấy trong vùng hồng ngoại. Chúng tôi mô hình hóa các khí quyển giống Trái Đất, giống Sao Kim, cũng như các khí quyển sơ cấp H₂-He với các mức kim loại khác nhau so với Mặt Trời, và trình bày các kiểu khí hậu cũng như các đặc trưng quang phổ tương ứng, so sánh với dữ liệu quan sát. Kết quả của chúng tôi cho thấy K2-18b có một khí quyển H₂-He với lượng H₂O và CH₄ hạn chế. Các kết quả không ủng hộ khả năng K2-18b có một hồ chứa nước tiếp xúc trực tiếp với khí quyển, điều này sẽ làm giảm chiều cao thang khí quyển, do đó làm giảm biên độ các đặc trưng quang phổ, không phù hợp với các quan sát. Chúng tôi cũng đã thực hiện các kiểm tra đối với các khí quyển H₂-He có độ kim loại lên đến 50 lần so với Mặt Trời, tất cả đều phù hợp với các quan sát.
|
vi
|
The relationship between variability, luminosity and redshift in the South Galactic Pole QSO sample is examined in an effort to disentangle the effects of luminosity and redshift in the amplitude of the optical variations. The anticorrelation between variability and luminosity found by other authors is confirmed. Our analysis also supports claims that variability increases with redshift, most likely due to an anticorrelation between variability and wavelength. In particular, our parametric fits show that the QSO variability-wavelength relation is consistent with that observed in low-luminosity nearby active galactic nuclei. The results are used to constrain Poissonian-type models. We find that if QSO variability results from a random superposition of pulses, then the individual events must have B-band energies between $\sim 10^{50}$ and a few times $10^{51}$ erg and time-scales of $\sim 2$ yr. Generalized Poissonian models in which the pulse energy and lifetime scale with luminosity are also discussed.
|
يتم فحص العلاقة بين التباين واللمعان والانزياح الأحمر في عينة الكوازارات عند القطب الجنوبي للدرب اللبني، في محاولة لفصل تأثيرات اللمعان والانزياح الأحمر على سعة التغيرات البصرية. ويتم تأكيد العلاقة العكسية بين التباين واللمعان التي وجدها باحثون آخرون. كما تدعم تحليلاتنا الادعاءات بأن التباين يزداد مع الانزياح الأحمر، ويرجع ذلك على الأرجح إلى علاقة عكسية بين التباين والطول الموجي. وعلى وجه الخصوص، تُظهر نماذج المطابقة البارامترية لدينا أن علاقة تباين الكوازار بالطول الموجي تتماشى مع العلاقة التي تُلاحظ في النوى المجرية النشطة القريبة ذات اللمعان المنخفض. وتُستخدم النتائج للحد من النماذج ذات الطراز البُواسيوني. نجد أنه إذا كان تباين الكوازارات ناتجًا عن تراكب عشوائي للنبضات، فيجب أن تكون طاقات النبضات الفردية في نطاق الحزمة B بين ∼10⁵⁰ وبضع مرات 10⁵¹ إرج، ومع مقاييس زمنية تبلغ نحو سنتين. كما تُناقش النماذج البُواسيونية المعممة التي تتغير فيها طاقة النبضة ومدتها حسب اللمعان.
|
ar
|
Subspace models play an important role in a wide range of signal processing tasks, and this paper explores how the pairwise geometry of subspaces influences the probability of misclassification. When the mismatch between the signal and the model is vanishingly small, the probability of misclassification is determined by the product of the sines of the principal angles between subspaces. When the mismatch is more significant, the probability of misclassification is determined by the sum of the squares of the sines of the principal angles. Reliability of classification is derived in terms of the distribution of signal energy across principal vectors. Larger principal angles lead to smaller classification error, motivating a linear transform that optimizes principal angles. The transform presented here (TRAIT) preserves some specific characteristic of each individual class, and this approach is shown to be complementary to a previously developed transform (LRT) that enlarges inter-class distance while suppressing intra-class dispersion. Theoretical results are supported by demonstration of superior classification accuracy on synthetic and measured data even in the presence of significant model mismatch.
|
سب اسپیس ماڈلز سگنل پروسیسنگ کے وسیع پیمانے پر کاموں میں اہم کردار ادا کرتے ہیں، اور اس مقالے میں یہ بحث کی گئی ہے کہ کس طرح سب اسپیس کی جوڑی وار جیومیٹری غلط طبقہ بندی کے امکان کو متاثر کرتی ہے۔ جب سگنل اور ماڈل کے درمیان میسمیچ نہایت ہی تھوڑا ہوتا ہے، تو غلط طبقہ بندی کا امکان سب اسپیس کے بنیادی زاویوں کی سائنز کے حاصل ضرب پر منحصر ہوتا ہے۔ جب میسمیچ زیادہ واضح ہوتا ہے، تو غلط طبقہ بندی کا امکان بنیادی زاویوں کی سائنز کے مربعات کے مجموعے پر منحصر ہوتا ہے۔ طبقہ بندی کی قابل اعتمادی بنیادی ویکٹرز میں سگنل توانائی کی تقسیم کے تناظر میں حاصل کی گئی ہے۔ بڑے بنیادی زاویے چھوٹی طبقہ بندی کی غلطی کی طرف لے جاتے ہیں، جو ایک لکیری ٹرانسفارم کی حوصلہ افزائی کرتے ہیں جو بنیادی زاویوں کو بہتر بناتا ہے۔ یہاں پیش کردہ ٹرانسفارم (ٹریٹ) ہر ایک الگ الگ طبقے کی کچھ مخصوص خصوصیت کو برقرار رکھتا ہے، اور یہ طریقہ پہلے سے تیار کردہ ٹرانسفارم (ایل آر ٹی) کے مکمل متبادل ثابت ہوتا ہے جو داخلی طبقاتی تقسیم کو کم کرتے ہوئے بین الطبقاتی فاصلے کو بڑھاتا ہے۔ نظریاتی نتائج مصنوعی اور ناپے گئے ڈیٹا پر بہتر طبقہ بندی کی درستگی کے مظاہرے کے ذریعے تقویت پاتے ہیں، حتیٰ کہ نمایاں ماڈل میسمیچ کی موجودگی میں بھی۔
|
ur
|
We report a fully quantum-dynamical study of the intramolecular vibrational energy redistribution (IVR) in the electronic ground state of carbonyl sulfide (OCS), which is a prototype of an isolated many-body quantum system with strong internal couplings and non-Rice-Ramsperger-Kassel-Marcus (RRKM) behavior. We pay particular attention to the role of many-body localization and the approach to thermalization, which currently are topics of considerable interest, as they pertain to the very foundations of statistical mechanics and thermodynamics. We employ local-mode (valence) coordinates and consider initial excitations localized in one local mode, with energies ranging from low to near the dissociation threshold, where the classical dynamics have been shown to be chaotic. We propagate the nuclear wavepacket on the potential energy surface by means of the numerically exact multiconfiguration time-dependent Hartree method and employ mean local energies, time-dependent and time-averaged populations in quantum number space, energy distributions, entanglement entropies, local population distributions, microcanonical averages, and dissociation probabilities, as diagnostic tools. This allows us to identify a continuous localization $\rightarrow$ delocalization transition in the energy flow, associated with the onset of quantum chaos, as the excitation energy increases up to near the dissociation threshold. Moreover, we find that at this energy and $\sim$1 ps the molecule nearly thermalizes. Furthermore, we observe that IVR is so slow that the molecule begins to dissociate well before such quasi-thermalization is complete, in accordance with earlier classical-mechanical predictions of non-RRKM behavior.
|
Мы сообщаем о полностью квантово-динамическом исследовании внутримолекулярной перераспределения колебательной энергии (IVR) в электронном основном состоянии карбонила сульфида (OCS), которое является типичным примером изолированной квантовой системы с большим числом тел, сильной внутренней связью и поведением, отличным от модели Райса – Рамспергера – Кассела – Маркуса (RRKM). Особое внимание мы уделяем роли локализации многих тел и приближению к термализации, что в настоящее время представляет значительный интерес, поскольку затрагивает основы статистической механики и термодинамики. Мы используем координаты локальных колебательных мод (валентные координаты) и рассматриваем начальные возбуждения, локализованные в одной локальной моде, с энергиями в диапазоне от низких до близких к порогу диссоциации, где классическая динамика является хаотической. Мы распространяем волновой пакет ядер по поверхности потенциальной энергии с помощью численно точного метода многофигурационной теории зависящей от времени функции Хартри и применяем в качестве диагностических инструментов средние локальные энергии, зависящие от времени и усреднённые по времени заселённости в пространстве квантовых чисел, распределения энергии, энтропии запутанности, распределения локальной заселённости, микроканонические средние и вероятности диссоциации. Это позволяет нам выявить непрерывный переход от локализации к делокализации в потоке энергии, связанному с возникновением квантового хаоса по мере увеличения энергии возбуждения вплоть до значений, близких к порогу диссоциации. Кроме того, мы обнаруживаем, что при этой энергии и примерно через 1 пс молекула почти полностью термализуется. Далее мы наблюдаем, что IVR протекает настолько медленно, что молекула начинает диссоциировать задолго до завершения такой квази-термализации, что согласуется с более ранними предсказаниями классической механики о поведении, отличном от RRKM.
|
ru
|
Cell proliferation, apoptosis, and myosin-dependent contraction can generate elastic stress and strain in living tissues, which may be dissipated by internal rearrangement through cell topological transition and cytoskeletal reorganization. Moreover, cells and tissues can change their sizes in response to mechanical cues. The present work demonstrates the role of tissue compressibility and internal rearranging activities on its size and mechanics regulation in the context of differential growth induced by a field of growth-promoting chemical factors. We develop a mathematical model based on finite elasticity and growth theory and the reference map techniques to describe the coupled tissue growth and mechanics in the Eulerian frame. We incorporate the tissue rearrangement by introducing a rearranging rate to the reference map evolution, leading to elastic-energy dissipation when tissue growth and deformation are in radial symmetry. By linearizing the model, we show that the stress follows the Maxwell-type viscoelastic relaxation. The rearrangement rate, which we call tissue fluidity, sets the stress relaxation time, and the ratio between the shear modulus and the fluidity sets the tissue viscosity. By nonlinear simulation of growing tissue spheroids and discs with graded growth rates along the radius, we find that the tissue compressibility and fluidity influence their equilibrium size. By comparing the nonlinear simulations with the linear analytical solutions, we show the size change as a nonlinear effect due to the advection of the tissue density flow, which only occurs when both tissue compressibility and fluidity are small. We apply the model to study tumor spheroid growth and epithelial disc growth when a reaction-diffusion process determines the growth-promoting factor field.
|
细胞增殖、凋亡以及肌球蛋白依赖性收缩可在活体组织中产生弹性应力和应变，这些应力和应变可通过细胞拓扑转变和细胞骨架重组引起的内部重排而耗散。此外，细胞和组织可响应力学信号而改变其尺寸。本文研究了在由促进生长的化学因子场诱导的差异性生长背景下，组织可压缩性和内部重排活动对其尺寸和力学调控的作用。我们基于有限弹性与生长理论以及参考映射方法，建立了在欧拉框架下描述组织生长与力学耦合的数学模型。通过在参考映射演化中引入重排速率以纳入组织重排过程，当组织生长和变形具有径向对称性时，可导致弹性能量的耗散。通过对模型进行线性化分析，我们发现应力遵循麦克斯韦型黏弹性松弛行为。重排速率（我们称之为组织流动性）决定了应力松弛时间，而剪切模量与流动性的比值决定了组织的黏度。通过对具有沿半径方向梯度生长速率的生长组织球体和圆盘进行非线性模拟，我们发现组织的可压缩性和流动性会影响其平衡尺寸。通过将非线性模拟结果与线性解析解进行比较，我们揭示了尺寸变化是一种非线性效应，源于组织密度流的对流输运，该效应仅在组织可压缩性和流动性均较小时出现。我们将该模型应用于研究由反应-扩散过程决定生长促进因子场时的肿瘤球体生长和上皮圆盘生长。
|
zh
|
Let $kE$ denote the group algebra of an elementary abelian $p$-group of rank $r$ over an algebraically closed field of characteristic $p$. We investigate the functors $\mathcal{F}_i$ from $kE$-modules of constant Jordan type to vector bundles on $\mathbb{P}^{r-1}(k)$, constructed by Benson and Pevtsova. For a $kE$-module $M$ of constant Jordan type, we show that restricting the sheaf $\mathcal{F}_i(M)$ to a dimension $s-1$ linear subvariety of $\mathbb{P}^{r-1}(k)$ is equivalent to restricting $M$ along a corresponding rank $s$ shifted subgroup of $kE$ and then applying $\mathcal{F}_i$. In the case $r=2$, we examine the generic kernel filtration of $M$ in order to show that $\mathcal{F}_i(M)$ may be computed on certain subquotients of $M$ whose Loewy lengths are bounded in terms of $i$. More precise information is obtained by applying similar techniques to the $n$th power generic kernel filtration of $M$. The latter approach also allows us to generalise our results to higher ranks $r$.
|
Nechť $kE$ značí grupovou algebru elementární abelovské $p$-grupy řádu $r$ nad algebraicky uzavřeným tělesem charakteristiky $p$. Prozkoumáváme funktory $\mathcal{F}_i$ z kategorie $kE$-modulů konstantního Jordanova typu do kategorie vektorových bandlů na $\mathbb{P}^{r-1}(k)$, které zkonstruovali Benson a Pevtsova. Pro $kE$-modul $M$ konstantního Jordanova typu ukazujeme, že omezení svazku $\mathcal{F}_i(M)$ na $(s-1)$-rozměrnou lineární podvarieta $\mathbb{P}^{r-1}(k)$ je ekvivalentní omezení $M$ podél odpovídající posunuté podgrupy $kE$ řádu $s$ a následné aplikování funktoru $\mathcal{F}_i$. V případě $r=2$ zkoumáme filtraci obecného jádra modulu $M$, abychom ukázali, že $\mathcal{F}_i(M)$ lze počítat na určitých podfaktorech modulu $M$, jejichž Loewyho délky jsou omezeny v závislosti na $i$. Přesnější informace získáme aplikací podobných technik na $n$-tou filtraci obecného jádra modulu $M$. Tento přístup nám rovněž umožňuje zobecnit naše výsledky na vyšší hodnoty $r$.
|
cs
|
One of the mechanisms suggested for the L to T dwarf spectral type transition is the appearance of relatively cloud-free regions across the disk of brown dwarfs as they cool. The existence of partly cloudy regions has been supported by evidence for variability in dwarfs in the late L to early T spectral range, but no self-consistent atmosphere models of such partly cloudy objects have yet been constructed. Here we present a new approach for consistently modeling partly cloudy brown dwarfs and giant planets. We find that even a small fraction of cloud holes dramatically alter the atmospheric thermal profile, spectra, and photometric colors of a given object. With decreasing cloudiness objects briskly become bluer in J - K and brighten in J band, as is observed at the L/T transition. Model spectra of partly cloudy objects are similar to our models with globally homogenous, but thinner, clouds. Hence spectra alone may not be sufficient to distinguish partial cloudiness although variability and polarization measurements are potential observational signatures. Finally we note that partial cloud cover may be an alternative explanation for the blue L dwarfs.
|
មួយក្នុងចំណោមយន្តការដែលត្រូវបានស្នើឡើងសម្រាប់ការផ្លាស់ប្តូរពីប្រភេទវិវត្តន៍ L ទៅ T គឺការលេចចេញនៃតំបន់ដែលមានពពកតិចតួចនៅលើឌីស្ករបស់ផ្កាយត្រីតូច ដោយពួកវាត្រជាក់ចុះ។ ការមានវត្តមាននៃតំបន់ដែលពពកគ្របមិនទូទៅ ត្រូវបានគាំទ្រដោយភស្តុតាងនៃភាពប្រែប្រួលក្នុងផ្កាយត្រីតូចនៅក្នុងជួរវិវត្តន៍ពី L ចុង ទៅ T ដើម ប៉ុន្តែគំរូបរិយាកាសដែលមានលក្ខណៈស៊ីសង្វាក់គ្នាសម្រាប់វត្ថុដែលមានពពកគ្របមិនទូទៅទាំងនេះ មិនទាន់ត្រូវបានបង្កើតឡើងនៅឡើយ។ នៅទីនេះ យើងស្នើវិធីសាស្ត្រថ្មីមួយសម្រាប់គំរូវត្ថុដែលមានពពកគ្របមិនទូទៅដោយស៊ីសង្វាក់គ្នា ទាំងផ្កាយត្រីតូច និងភពយក្ស។ យើងរកឃើញថា ទោះបីជាបរិមាណតិចតួចនៃរន្ធពពកក៏ដោយ ក៏វាបំលាស់ប្តូរគំរូសីតុណ្ហភាព វរ្មណវិទ្យា និងពណ៌ដែលវាស់ពីភាពភ្លឺរបស់វត្ថុមួយយ៉ាងខ្លាំង។ កាលពីពពកថយចុះ វត្ថុកាន់តែភ្លឺខៀវក្នុង J - K និងភ្លឺឡើងក្នុងខ្សែ J ដូចដែលត្រូវបានសង្កេតឃើញនៅពេលផ្លាស់ប្តូរពី L ទៅ T។ វរ្មណវិទ្យាគំរូរបស់វត្ថុដែលមានពពកគ្របមិនទូទៅ ស្រដៀងនឹងគំរូរបស់យើងដែលមានពពកស្មើៗគ្នាទូទៅ ប៉ុន្តែស្តើងជាង។ ដូច្នេះ វរ្មណវិទ្យាតែមួយគត់ប្រហែលមិនគ្រប់គ្រាន់ដើម្បីបែងចែកភាពមានពពកគ្របមិនទូទៅទេ ទោះបីជាការវាស់ការប្រែប្រួល និងការវាស់ការរំអិលអាចជាសញ្ញាសង្កេតដែលអាចធ្វើទៅបានក៏ដោយ។ ទីបំផុត យើងសម្គាល់ថា ការគ្របពពកមិនទូទៅ ប្រហែលជាជាការបកស្រាយជំនួសមួយសម្រាប់ផ្កាយត្រីតូច L ដែលមានពណ៌ខៀវ។
|
km
|
Following Riley's work, for each 2-bridge link $K(r)$ of slope $r\in\QQ$ and an integer or a half-integer $n$ greater than 1, we introduce the {\it Heckoid orbifold $\orbs(r;n)$} and the {\it Heckoid group $\Hecke(r;n)=\pi_1(\orbs(r;n))$ of index $n$ for $K(r)$}. When $n$ is an integer, $\orbs(r;n)$ is called an {\it even} Heckoid orbifold; in this case, the underlying space is the exterior of $K(r)$, and the singular set is the lower tunnel of $K(r)$ with index $n$. The main purpose of this note is to announce answers to the following questions for even Heckoid orbifolds. (1) For an essential simple loop on a 4-punctured sphere $\PConway$ in $\orbs(r;n)$ determined by the 2-bridge sphere of $K(r)$, when is it null-homotopic in $\orbs(r;n)$? (2) For two distinct essential simple loops on $\PConway$, when are they homotopic in $\orbs(r;n)$? We also announce applications of these results to character varieties, McShane's identity, and epimorphisms from 2-bridge link groups onto Heckoid groups.
|
Po práci Rileyho pro každý 2-mostkový uzel $K(r)$ se sklonem $r\in\QQ$ a celé číslo nebo polocelé číslo $n$ větší než 1 zavádíme {\it Heckoidův orbifold $\orbs(r;n)$} a {\it Heckidovu grupu $\Hecke(r;n)=\pi_1(\orbs(r;n))$ indexu $n$ pro $K(r)$}. Když $n$ je celé číslo, nazývá se $\orbs(r;n)$ {\it sudým} Heckidovým orbifoldem; v tomto případě je podkladovým prostorem exteriér $K(r)$ a singulární množinou je dolní tunel $K(r)$ s indexem $n$. Hlavním cílem této poznámky je oznámit odpovědi na následující otázky pro sudé Heckidovy orbifol dy. (1) Pro esenciální jednoduchou smyčku na čtyři-otvorované sféře $\PConway$ v $\orbs(r;n)$ určenou 2-mostkovou sférou $K(r)$, kdy je kontrahovatelná v $\orbs(r;n)$? (2) Pro dvě různé esenciální jednoduché smyčky na $\PConway$, kdy jsou homotopické v $\orbs(r;n)$? Dále také oznámíme aplikace těchto výsledků na varietu charakterů, McShaneovu identitu a epimorfismy z grup 2-mostkových uzlů na Heckidovy grupy.
|
cs
|
The understanding of the characteristics of a magnetic layer in a different environment is crucial for any spintronics application. Before practical applications, thorough scrutiny of such devices is compulsory. Here we study such a potential Hall device of MgO-capped Hf/GdFeCo bilayer (FeCo-rich) for magnetization relaxation around nucleation fields at different voltage probe line widths and dc sensing currents. The device is characterized by anomalous Hall measurements in transverse and longitudinal Hall geometries for two different probe widths A (5 micrometer) and B (1 micrometer). The coercivities of the Hall loops (\r{ho}xy-H and Rxx-H) drop with increasing the sense current for both the probes. For probe B, the sharp and large drop in coercivity (\r{ho}xy-H loops) at comparatively lower sensing currents is observed, which is attributed to the negligible current shunting and presence of pinning site at B caused by the patterning process. The average domain wall velocities at various sensing currents for probe B are found to be smaller than probe A, from the transverse and longitudinal Hall geometry magnetization relaxation measurements, which agrees with pinning sites and Joule heating effect at probe B. The notch position in the pattern and the longitudinal Hall resistance curve peak shape suggest the domain wall propagation direction from probe B to probe A in the current channel. This study highlights the domain wall propagation at different nucleation fields, sensing currents, and the Hall probe aspect ratios.
|
বিভিন্ন পরিবেশে চৌম্বকীয় স্তরের বৈশিষ্ট্যগুলির উপলব্ধি যেকোনো স্পিনট্রনিক্স প্রয়োগের জন্য অত্যন্ত গুরুত্বপূর্ণ। ব্যবহারিক প্রয়োগের আগে এমন যন্ত্রগুলির একটি গভীর পর্যালোচনা অপরিহার্য। এখানে আমরা বিভিন্ন ভোল্টেজ প্রোব রেখার প্রস্থ এবং ডিসি সেন্সিং কারেন্টের জন্য নিউক্লিয়েশন ক্ষেত্রের আশেপাশে চৌম্বকীকরণ শিথিলীকরণের জন্য MgO-ক্যাপড Hf/GdFeCo ডাবলস্তর (FeCo-প্রধান) এর এমন একটি সম্ভাব্য হল যন্ত্র নিয়ে অধ্যয়ন করি। দুটি ভিন্ন প্রোব প্রস্থ A (5 মাইক্রোমিটার) এবং B (1 মাইক্রোমিটার) এর জন্য আড়াআড়ি এবং দৈর্ঘ্যবর্তী হল জ্যামিতির মাধ্যমে অস্বাভাবিক হল পরিমাপের মাধ্যমে যন্ত্রটির বৈশিষ্ট্য নির্ণয় করা হয়। উভয় প্রোবের জন্য সেন্সিং কারেন্ট বৃদ্ধির সাথে সাথে হল লুপগুলির (\r{ho}xy-H এবং Rxx-H) সমর্থন ক্ষেত্র হ্রাস পায়। প্রোব B-এর ক্ষেত্রে তুলনামূলকভাবে কম সেন্সিং কারেন্টে সমর্থন ক্ষেত্রে তীব্র ও বৃহৎ পতন (\r{ho}xy-H লুপগুলি) লক্ষ্য করা যায়, যার কারণ হিসাবে প্রোব B-এ কারেন্ট শান্টিংয়ের নগণ্যতা এবং প্যাটার্নিং প্রক্রিয়ার কারণে পিনিং সাইটের উপস্থিতি দেখানো হয়। আড়াআড়ি এবং দৈর্ঘ্যবর্তী হল জ্যামিতির চৌম্বকীকরণ শিথিলীকরণ পরিমাপ থেকে দেখা যায় যে বিভিন্ন সেন্সিং কারেন্টের জন্য প্রোব B-এর গড় ডোমেইন ওয়াল বেগ প্রোব A-এর চেয়ে কম, যা প্রোব B-এ পিনিং সাইট এবং জুল তাপন প্রভাবের সাথে সামঞ্জস্যপূর্ণ। প্যাটার্নের নট অবস্থান এবং দৈর্ঘ্যবর্তী হল রোধ বক্ররেখার শীর্ষ আকৃতি থেকে প্রস্তাব করা হয় যে কারেন্ট চ্যানেলে ডোমেইন ওয়াল প্রোব B থেকে প্রোব A-এর দিকে ছড়িয়ে পড়ে। এই অধ্যয়নটি বিভিন্ন নিউক্লিয়েশন ক্ষেত্র, সেন্সিং কারেন্ট এবং হল প্রোবের আকৃতির অনুপাতে ডোমেইন ওয়াল প্রসারণের ওপর আলোকপাত করে।
|
bn
|
As a sub-array of the Large High Altitude Air Shower Observatory (LHAASO), KM2A is mainly designed to cover a large fraction of the northern sky to hunt for gamma-ray sources at energies above 10 TeV. Even though the detector construction is still underway, a half of the KM2A array has been operating stably since the end of 2019. In this paper, we present the pipeline of KM2A data analysis and the first observation on the Crab Nebula, a standard candle in very high energy gamma-ray astronomy. We detect gamma-ray signals from the Crab Nebula in both energy ranges of 10$-$100 TeV and $>$100 TeV with high significance, by analyzing the KM2A data of 136 live days between December 2019 and May 2020. With the observations, we test the detector performance including angular resolution, pointing accuracy and cosmic ray background rejection power. The energy spectrum of the Crab Nebula in the energy range 10-250 TeV fits well with a single power-law function dN/dE =(1.13$\pm$0.05$_{stat}$$\pm$0.08$_{sys}$)$\times$10$^{-14}$$\cdot$(E/20TeV)$^{-3.09\pm0.06_{stat}\pm0.02_{sys}}$ cm$^{-2}$ s$^{-1}$ TeV$^{-1}$. It is consistent with previous measurements by other experiments. This opens a new window of gamma-ray astronomy above 0.1 PeV through which ultrahigh-energy gamma-ray new phenomena, such as cosmic PeVatrons, might be discovered.
|
ایل اچ اے اے ایس او (بڑی بلندی والی ایئر شاور آبزرویٹری) کی ایک ذیلی ترتیب کے طور پر، کے ایم 2 اے کا بنیادی مقصد شمالی آسمان کے بڑے حصے کا احاطہ کرنا ہے تاکہ 10 ٹی وی سے زیادہ توانائی پر گاما رے ذرائع کی تلاش کی جا سکے۔ اگرچہ تجسس کی تعمیر ابھی جاری ہے، تاہم کے ایم 2 اے کی نصف ترتیب دسمبر 2019 کے آخر سے مستحکم طور پر کام کر رہی ہے۔ اس مقالے میں، ہم کے ایم 2 اے ڈیٹا تجزیہ کے طریقہ کار اور بہت زیادہ توانائی والی گاما رے فلکیات میں ایک معیاری شمع کے طور پر جانے جانے والے کریب نیبولا پر اس کی پہلی مشاہدہ کی رپورٹ پیش کرتے ہیں۔ ہم دسمبر 2019 سے مئی 2020 کے درمیان 136 متحرک دنوں کے کے ایم 2 اے ڈیٹا کے تجزیہ کے ذریعے 10$-$100 ٹی وی اور $>$100 ٹی وی دونوں توانائی کی حدود میں کریب نیبولا سے گاما رے سگنلز کا اعلیٰ معنویت کے ساتھ پتہ لگاتے ہیں۔ ان مشاہدات کے ذریعے، ہم زاویہ وضاحت، ہدف کی درستگی اور کاسمک رے پس منظر کو خارج کرنے کی صلاحیت سمیت تجسس کی کارکردگی کا امتحان لیتے ہیں۔ 10 تا 250 ٹی وی کی توانائی کی حد میں کریب نیبولا کا توانائی طیف ایک مفرد پاور لا فنکشن dN/dE =(1.13$\pm$0.05$_{stat}$$\pm$0.08$_{sys}$)$\times$10$^{-14}$$\cdot$(E/20TeV)$^{-3.09\pm0.06_{stat}\pm0.02_{sys}}$ cm$^{-2}$ s$^{-1}$ TeV$^{-1}$ کے ساتھ بہت اچھی طرح فٹ ہوتا ہے۔ یہ دوسرے تجربات کے پچھلے پیمائشوں کے ساتھ مطابقت رکھتا ہے۔ یہ 0.1 پی ای وی سے زیادہ گاما رے فلکیات کی ایک نئی کھڑکی کھولتا ہے جس کے ذریعے کاسمک پی ای وی ٹرانز جیسے انتہائی زیادہ توانائی والے گاما رے کے نئے مظاہر کی دریافت ممکن ہو سکتی ہے۔
|
ur
|
The purpose of a program analysis is to compute an abstract meaning for a program which approximates its dynamic behaviour. A compositional program analysis accomplishes this task with a divide-and-conquer strategy: the meaning of a program is computed by dividing it into sub-programs, computing their meaning, and then combining the results. Compositional program analyses are desirable because they can yield scalable (and easily parallelizable) program analyses. This paper presents algebraic framework for designing, implementing, and proving the correctness of compositional program analyses. A program analysis in our framework defined by an algebraic structure equipped with sequencing, choice, and iteration operations. From the analysis design perspective, a particularly interesting consequence of this is that the meaning of a loop is computed by applying the iteration operator to the loop body. This style of compositional loop analysis can yield interesting ways of computing loop invariants that cannot be defined iteratively. We identify a class of algorithms, the so-called path-expression algorithms [Tarjan1981,Scholz2007], which can be used to efficiently implement analyses in our framework. Lastly, we develop a theory for proving the correctness of an analysis by establishing an approximation relationship between an algebra defining a concrete semantics and an algebra defining an analysis.
|
O objetivo de uma análise de programa é calcular um significado abstrato para um programa que aproxime seu comportamento dinâmico. Uma análise composicional de programas realiza esta tarefa com uma estratégia de divisão e conquista: o significado de um programa é calculado dividindo-o em subprogramas, computando o significado de cada um e combinando os resultados. Análises composicionais de programas são desejáveis porque podem gerar análises de programas escaláveis (e facilmente paralelizáveis). Este artigo apresenta um framework algébrico para projetar, implementar e provar a correção de análises composicionais de programas. Uma análise de programa em nosso framework é definida por uma estrutura algébrica equipada com operações de sequenciamento, escolha e iteração. Do ponto de vista do projeto da análise, uma consequência particularmente interessante disso é que o significado de um laço é calculado aplicando o operador de iteração ao corpo do laço. Esse estilo de análise composicional de laços pode gerar maneiras interessantes de calcular invariantes de laço que não podem ser definidos iterativamente. Identificamos uma classe de algoritmos, os chamados algoritmos de expressão de caminhos [Tarjan1981, Scholz2007], que podem ser usados para implementar eficientemente análises em nosso framework. Por fim, desenvolvemos uma teoria para provar a correção de uma análise ao estabelecer uma relação de aproximação entre uma álgebra que define uma semântica concreta e uma álgebra que define uma análise.
|
pt
|
Ageing civil infrastructure systems require imminent attention before any failure mechanism becomes critical. Structural Health Monitoring (SHM) is employed to track inputs and/or responses of structural systems for decision support. Inspections and structural health monitoring require field visits, and subsequently expert assessment of critical elements at site, which may be both time-consuming and costly. Also, fieldwork including visits and inspections may pose danger, require personal protective equipment and structure closures during the fieldwork. To address some of these issues, a Virtual Reality (VR) collaborative application is developed to bring the structure and SHM data from the field to the office such that many experts from different places can simultaneously virtually visit the bridge structure for final assessment. In this work, we present an SHM system in a VR environment that includes the technical and visual information necessary for the engineers to make decisions for a footbridge on the campus of the University of Central Florida. In this VR application, for the visualization stage, UAV (Unmanned Air Vehicle) photogrammetry and LiDAR (Light Detection and Ranging) methods are used to capture the bridge. For the technical assessment stage, Finite Element Analysis (FEA) and Operational Modal Analysis (OMA) from vibration data as part of SHM are analyzed. To better visualize the dynamic response of the structure, the operational behaviour from the FEA is reflected on the LiDAR point cloud model for immersive. The multi-user feature allowing teams to collaborate simultaneously is essential for decision-making activities. In conclusion, the proposed VR environment offers the potential to provide beneficial features with further automated and real-time improvements along with the SHM and FEA models.
|
Ang pagtanda ng mga sibil na sistema ng imprastraktura ay nangangailangan ng agarang atensyon bago pa man maging kritikal ang anumang mekanismo ng pagkabigo. Ginagamit ang Structural Health Monitoring (SHM) upang subaybayan ang mga input at/o tugon ng mga sistematikong istraktura bilang suporta sa paggawa ng desisyon. Ang mga inspeksyon at pagsubaybay sa kalusugan ng istraktura ay nangangailangan ng pagbisita sa lugar at kalaunan ay pagtatasa ng mga eksperto sa mga kritikal na bahagi sa pook, na maaaring parehong maabala at mahal. Bukod dito, ang gawaing pampook kabilang ang mga pagbisita at inspeksyon ay maaaring magdulot ng panganib, nangangailangan ng personal protective equipment, at pagsasara ng istraktura habang isinasagawa ang gawain. Upang tugunan ang ilan sa mga isyung ito, isang Virtual Reality (VR) kolaboratibong aplikasyon ang binuo upang dalhin ang istraktura at datos ng SHM mula sa pook patungo sa opisina, upang magkaron ng posibilidad na magkaroon ng sabay-sabay na virtual na pagbisita ang maraming eksperto mula sa iba't ibang lugar sa istrakturang tulay para sa huling pagtatasa. Sa pag-aaral na ito, iniharap namin ang isang sistema ng SHM sa isang kapaligiran ng VR na naglalaman ng teknikal at biswal na impormasyon na kinakailangan ng mga inhinyero upang magdesisyon para sa isang pedestrian bridge sa loob ng kampus ng University of Central Florida. Sa aplikasyong ito, para sa yugto ng pagvisualize, ginamit ang UAV (Unmanned Air Vehicle) photogrammetry at LiDAR (Light Detection and Ranging) upang i-capture ang tulay. Para naman sa yugto ng teknikal na pagtatasa, isinagawa ang Finite Element Analysis (FEA) at Operational Modal Analysis (OMA) mula sa datos ng vibration na bahagi ng SHM. Upang mapaganda ang pagvisualize sa dinamikong tugon ng istraktura, isinasalamin ang operasyonal na pag-uugali mula sa FEA sa LiDAR point cloud model para sa immersive na karanasan. Ang tampok na multi-user na nagbibigay-daan sa mga grupo na magtrabaho nang sabay-sabay ay mahalaga para sa mga gawaing paggawa ng desisyon. Sa konklusyon, ang iminungkahing kapaligiran ng VR ay may potensyal na magbigay ng kapaki-pakinabang na mga tampok na may karagdagang automated at real-time na mga pagpapabuti kasama ang mga modelo ng SHM at FEA.
|
tl
|
Plant domestication involved a process of selection through human agency of a series of traits collectively termed the domestication syndrome. Current debate concerns the pace at which domesticated plants emerged from cultivated wild populations and how many genes were involved. Here we present simulations that test how many genes could have been involved by considering the cost of selection. We demonstrate the selection load that can be endured by populations increases with decreasing selection coefficients and greater numbers of loci down to values of about s = 0.005, causing a driving force that increases the number of loci under selection. As the number of loci under selection increases, an effect of co-selection increases resulting in individual unlinked loci being fixed more rapidly in out-crossing populations, representing a second driving force to increase the number of loci under selection. In inbreeding systems co-selection results in interference and reduced rates of fixation but does not reduce the size of the selection load that can be endured. These driving forces result in an optimum pace of genome evolution in which 50-100 loci are the most that could be under selection in a cultivation regime. Furthermore, the simulations do not preclude the existence of selective sweeps but demonstrate that they come at a cost of the selection load that can be endured and consequently a reduction of the capacity of plants to adapt to new environments, which may contribute to the explanation of why selective sweeps have been so rarely detected in genome studies.
|
ການລ້ຽງດູພືດມີການຄັດເລືອກຜ່ານການກະທຳຂອງມະນຸດຕໍ່ຊຸດຂອງລັກສະນະທີ່ຖືກເອີ້ນຮ່ວມກັນວ່າ ລະບົບຄວາມເປັນພືດລ້ຽງ. ການຖົກຖຽງທີ່ກຳລັງເກີດຂຶ້ນໃນປັດຈຸບັນກ່ຽວຂ້ອງກັບຄວາມໄວທີ່ພືດລ້ຽງເກີດຂຶ້ນຈາກກຸ່ມພືດທີ່ຖືກປູກຈາກພືດປ່າ ແລະ ຈຳນວນຢີນທີ່ກ່ຽວຂ້ອງ. ນີ້ພວກເຮົານຳສະເໜີການຈຳລອງທີ່ທົດສອບວ່າຈຳນວນຢີນທີ່ກ່ຽວຂ້ອງໄດ້ແນວໃດໂດຍພິຈາລະນາຄ່າໃຊ້ຈ່າຍຂອງການຄັດເລືອກ. ພວກເຮົາສະແດງໃຫ້ເຫັນວ່າພະລັງງານຄັດເລືອກທີ່ປົກກະຕິສາມາດຮັບໄດ້ຈະເພີ່ມຂຶ້ນໃນຂະນະທີ່ສຳປະສິດຄັດເລືອກຫຼຸດລົງ ແລະ ຈຳນວນຂອງເດີ່ນ (loci) ເພີ່ມຂຶ້ນຈົນເຖິງຄ່າປະມານ s = 0.005, ເຮັດໃຫ້ເກີດແຮງຂັບເຄື່ອນທີ່ເພີ່ມຈຳນວນເດີ່ນທີ່ຢູ່ພາຍໃຕ້ການຄັດເລືອກ. ໃນຂະນະທີ່ຈຳນວນເດີ່ນທີ່ຢູ່ພາຍໃຕ້ການຄັດເລືອກເພີ່ມຂຶ້ນ, ຜົນກະທົບຈາກການຄັດເລືອກຮ່ວມກັນຈະເພີ່ມຂຶ້ນເຮັດໃຫ້ເດີ່ນທີ່ບໍ່ເຊື່ອມຕໍ່ກັນແຕ່ລະຕົວຖືກກຳນົດໄວ້ຢ່າງໄວວາໃນກຸ່ມທີ່ມີການຂ້າມກັນ, ເຊິ່ງເປັນແຮງຂັບເຄື່ອນທີສອງທີ່ເພີ່ມຈຳນວນເດີ່ນທີ່ຢູ່ພາຍໃຕ້ການຄັດເລືອກ. ໃນລະບົບທີ່ມີການຂ້າມພັນທຸກຳ ການຄັດເລືອກຮ່ວມກັນຈະນຳໄປສູ່ການລົບກວນ ແລະ ອັດຕາການກຳນົດທີ່ຫຼຸດລົງ ແຕ່ກໍບໍ່ຫຼຸດລົງຂະໜາດຂອງພະລັງງານຄັດເລືອກທີ່ສາມາດຮັບໄດ້. ແຮງຂັບເຄື່ອນເຫຼົ່ານີ້ນຳໄປສູ່ຄວາມໄວທີ່ເໝາະສົມຂອງການວິວັດທະນາການຂອງຈີໂນມ ໂດຍທີ່ 50-100 ເດີ່ນ ແມ່ນຈຳນວນສູງສຸດທີ່ສາມາດຢູ່ພາຍໃຕ້ການຄັດເລືອກໃນລະບົບການປູກ. ພ້ອມກັນນັ້ນ, ການຈຳລອງກໍບໍ່ໄດ້ຂັດຂວາງການມີຢູ່ຂອງການຄັດເລືອກແບບເຄື່ອນທີ່ໄວ (selective sweeps) ແຕ່ສະແດງໃຫ້ເຫັນວ່າມັນມາພ້ອມກັບຄ່າໃຊ້ຈ່າຍຂອງພະລັງງານຄັດເລືອກທີ່ສາມາດຮັບໄດ້ ແລະ ສະນັ້ນຈຶ່ງຫຼຸດຜ່ອນຄວາມສາມາດຂອງພືດໃນການປັບໂຕຕໍ່ສິ່ງແວດລ້ອມໃໝ່, ເຊິ່ງອາດຈະເປັນສ່ວນໜຶ່ງທີ່ອະທິບາຍວ່າເປັນຫຍັງການຄັດເລືອກແບບເຄື່ອນທີ່ໄວຈຶ່ງຖືກພົບເຫັນຢ່າງຫາຍາກໃນການສຶກສາຈີໂນມ.
|
lo
|
Reinforcement learning (RL) is a popular paradigm for addressing sequential decision tasks in which the agent has only limited environmental feedback. Despite many advances over the past three decades, learning in many domains still requires a large amount of interaction with the environment, which can be prohibitively expensive in realistic scenarios. To address this problem, transfer learning has been applied to reinforcement learning such that experience gained in one task can be leveraged when starting to learn the next, harder task. More recently, several lines of research have explored how tasks, or data samples themselves, can be sequenced into a curriculum for the purpose of learning a problem that may otherwise be too difficult to learn from scratch. In this article, we present a framework for curriculum learning (CL) in reinforcement learning, and use it to survey and classify existing CL methods in terms of their assumptions, capabilities, and goals. Finally, we use our framework to find open problems and suggest directions for future RL curriculum learning research.
|
Zesilující učení (reinforcement learning, RL) je populární paradigma pro řešení sekvenčních rozhodovacích úloh, ve kterých agent disponuje pouze omezenou zpětnou vazbou od prostředí. Navzdory mnoha pokrokům během uplynulých tří desetiletí stále v mnoha oblastech vyžaduje učení velké množství interakcí s prostředím, což může být v reálných scénářích nepřijatelně nákladné. K řešení tohoto problému bylo na zesilující učení aplikováno přenosové učení (transfer learning), díky němuž lze využít zkušenosti získané při řešení jedné úlohy při učení se další, obtížnější úloze. V poslední době několik výzkumných směrů zkoumalo, jak lze úlohy nebo samotné datové vzorky seřadit do učební osnovy (kurikula) za účelem zvládnutí problému, který by jinak byl příliš obtížný na to, aby se dal naučit od základů. V tomto článku představujeme rámec pro učení pomocí kurikula (curriculum learning, CL) v rámci zesilujícího učení a používáme jej k přehledu a klasifikaci stávajících metod CL podle jejich předpokladů, schopností a cílů. Nakonec tento rámec využíváme k identifikaci otevřených problémů a navrhujeme směry pro budoucí výzkum učení pomocí kurikula v zesilujícím učení.
|
cs
|
Rapid progress in nonlinear plasmonic metasurfaces enabled many novel optical characteristics for metasurfaces, with potential applications in frequency metrology, timing characterization and quantum information. However, the spectrum of nonlinear optical response was typically based upon the linear optical resonance. In this work, a wavelength-multiplexed nonlinear plasmon-MoS2 hybrid metasurface with suppression phenomenon was proposed, where multiple nonlinear signals could to be simultaneously processed and optionally tuned. A clear physical picture to depict the nonlinear plasmonic bound states in the continuum (BICs) was presented, from the perspective of both classical and quantum approaches. Particularly, beyond the ordinary plasmon-polariton effect, we numerically demonstrated a giant BIC-inspired second-order nonlinear susceptibility $10^{-5}$~$m/V$ of MoS2 in the infrared band. The novelty in our study lies in the presence of a quantum oscillator that can be adopted to both suppress and enhance the nonlinear quasi BICs. This selectable nonlinear BIC-based suppression and enhancement effect can optionally block undesired modes, resulting in narrower linewidth as well as smaller quantum decay rates, which is also promising in slow-light-associated technologies.
|
ភាពវឌ្ឍន៍យ៉ាងរហ័សនៅក្នុងផ្ទៃមេតាសូភ្លើប៊ែលប្លាសម៉ូនីលីនេអ៊ែរបានធ្វើឱ្យមានលក្ខណៈប្រភេទថ្មីៗជាច្រើនសម្រាប់ផ្ទៃមេតាសូភ្លើប៊ែល ដែលមានការអនុវត្តសក្ដានុពលនៅក្នុងការវាស់វែងប្រេកង់ ការចាត់ថ្នាក់ពេលវេលា និងព័ត៌មានប៉ាតង់។ ទោះជាយ៉ាងណា វិសាលភាពប្រតិកម្មប្រភេទថ្មីបានផ្អែកលើការបើកចំហរប្រភេទធម្មតា។ ក្នុងការសិក្សានេះ យើងបានស្នើអំពីផ្ទៃមេតាសូភ្លើប៊ែលប្លាសម៉ូនីលីនេអ៊ែរ- MoS2 ដែលបានបំបែកតាមរយៈប្រេកង់ ហើយមានបាតុភូតបំបាត់ ដែលសញ្ញាប្រភេទថ្មីជាច្រើនអាចត្រូវបានដំណើរការក្នុងពេលដំណាលគ្នា និងអាចត្រូវបានកែតម្រូវតាមបំណងបាន។ យើងបានផ្តល់រូបភាពរូបវិទ្យាច្បាស់លាស់មួយដើម្បីពិពណ៌នាអំពីស្ថានភាពប្រភេទថ្មីនៃប្លាសម៉ូនដែលមាននៅក្នុងបន្ត (BICs) ពីទស្សនៈទាំងបុរាណ និងប៉ាតង់។ ជាពិសេស លើសពីបាតុភូតប្លាសម៉ូន-ប៉ូឡារីតូន យើងបានបង្ហាញយ៉ាងច្បាស់អំពីសុពលភាពប្រភេទថ្មីទីពីរដែលមានទំហំធំ $10^{-5}$~$m/V$ នៃ MoS2 នៅក្នុងខ្សែអ៊ីនហ្វ្រារែដ។ ភាពថ្មីនៃការសិក្សារបស់យើងស្ថិតនៅក្នុងការមានអុស៊ីលាទ័រប៉ាតង់មួយ ដែលអាចត្រូវបានប្រើដើម្បីទាំងបំបាត់ និងបង្កើនស្ថានភាពប្រភេទថ្មីប្រភេទ BICs។ បាតុភូតបំបាត់ និងបង្កើនដែលអាចជ្រើសរើសបានដោយផ្អែកលើ BICs ប្រភេទថ្មីនេះ អាចបិទរបៀបដែលមិនចង់បានតាមបំណង ដែលនាំឱ្យមានបន្ទាត់ស្តើងជាង និងអត្រាធ្លាក់ចុះប៉ាតង់តិចជាង ដែលក៏មានសក្តានុពលនៅក្នុងបច្ចេកវិទ្យាដែលពាក់ព័ន្ធនឹងពន្លឺយឺតផងដែរ។
|
km
|
There is a growing trend in studying deep hashing methods for content-based image retrieval (CBIR), where hash functions and binary codes are learnt using deep convolutional neural networks and then the binary codes can be used to do approximate nearest neighbor (ANN) search. All the existing deep hashing papers report their methods' superior performance over the traditional hashing methods according to their experimental results. However, there are serious flaws in the evaluations of existing deep hashing papers: (1) The datasets they used are too small and simple to simulate the real CBIR situation. (2) They did not correctly include the search time in their evaluation criteria, while the search time is crucial in real CBIR systems. (3) The performance of some unsupervised hashing algorithms (e.g., LSH) can easily be boosted if one uses multiple hash tables, which is an important factor should be considered in the evaluation while most of the deep hashing papers failed to do so. We re-evaluate several state-of-the-art deep hashing methods with a carefully designed experimental setting. Empirical results reveal that the performance of these deep hashing methods are inferior to multi-table IsoH, a very simple unsupervised hashing method. Thus, the conclusions in all the deep hashing papers should be carefully re-examined.
|
বিষয়বস্তু-ভিত্তিক ছবি অনুসন্ধান (সিবিআইআর)-এর জন্য গভীর হ্যাশিং পদ্ধতি নিয়ে অধ্যয়নের একটি বৃদ্ধি পাওয়া প্রবণতা রয়েছে, যেখানে হ্যাশ ফাংশন এবং বাইনারি কোডগুলি গভীর কনভোলিউশনাল নিউরাল নেটওয়ার্ক ব্যবহার করে শেখানো হয় এবং তারপর বাইনারি কোডগুলি আনুমানিক সর্বনিকটতম প্রতিবেশী (এএনএন) অনুসন্ধানের জন্য ব্যবহার করা হয়। বিদ্যমান সমস্ত গভীর হ্যাশিং গবেষণাপত্রগুলি তাদের পরীক্ষামূলক ফলাফল অনুযায়ী ঐতিহ্যবাহী হ্যাশিং পদ্ধতির তুলনায় তাদের পদ্ধতির উন্নত কর্মদক্ষতা প্রতিবেদন করে। তবে, বিদ্যমান গভীর হ্যাশিং গবেষণাপত্রগুলির মূল্যায়নে গুরুতর ত্রুটি রয়েছে: (1) তারা যে ডেটাসেটগুলি ব্যবহার করেছে সেগুলি প্রকৃত সিবিআইআর পরিস্থিতি অনুকরণের জন্য খুবই ছোট এবং সহজ। (2) তারা মূল্যায়নের মাপকাঠিতে অনুসন্ধানের সময় সঠিকভাবে অন্তর্ভুক্ত করেনি, যদিও প্রকৃত সিবিআইআর সিস্টেমগুলিতে অনুসন্ধানের সময় অত্যন্ত গুরুত্বপূর্ণ। (3) কিছু অ-তত্ত্বাবধানযুক্ত হ্যাশিং অ্যালগরিদমের (যেমন, এলএসএইচ) কর্মদক্ষতা সহজেই বৃদ্ধি করা যায় যদি কেউ একাধিক হ্যাশ টেবিল ব্যবহার করে, যা মূল্যায়নের সময় বিবেচনার জন্য একটি গুরুত্বপূর্ণ বিষয়, কিন্তু বেশিরভাগ গভীর হ্যাশিং গবেষণাপত্র এই বিষয়টি করেনি। আমরা সতর্কভাবে নকশাকৃত একটি পরীক্ষামূলক সেটিং ব্যবহার করে কয়েকটি আধুনিক গভীর হ্যাশিং পদ্ধতির পুনর্মূল্যায়ন করি। প্রায়োগিক ফলাফলগুলি প্রকাশ করে যে এই গভীর হ্যাশিং পদ্ধতিগুলির কর্মদক্ষতা মাল্টি-টেবিল আইসোএইচ-এর তুলনায় খারাপ, যা একটি অত্যন্ত সহজ অ-তত্ত্বাবধানযুক্ত হ্যাশিং পদ্ধতি। সুতরাং, সমস্ত গভীর হ্যাশিং গবেষণাপত্রের উপসংহারগুলি সতর্কতার সাথে পুনরায় পরীক্ষা করা উচিত।
|
bn
|
We use current observations on the number statistics of gravitationally lensed optical arcs towards galaxy clusters to derive an upper limit on the cosmological mass density of the Universe. The gravitational lensing statistics due to foreground clusters combine properties of both cluster evolution, which is sensitive to the matter density, and volume change, which is sensitive to the cosmological constant. The uncertainties associated with the predicted number of lensing events, however, currently do not allow one to distinguish between flat and open cosmological models with and without a cosmological constant. Still, after accounting for known errors, and assuming that clusters in general have dark matter core radii of the order ~ 35 h^-1 kpc, we find that the cosmological mass density, Omega_m, is less than 0.56 at the 95% confidence. Such a dark matter core radius is consistent with cluster potentials determined recently by detailed numerical inversions of strong and weak lensing imaging data. If no core radius is present, the upper limit on Omega_m increases to 0.62 (95% confidence level). The estimated upper limit on Omega_m is consistent with various cosmological probes that suggest a low matter density for the Universe.
|
Využíváme současných pozorování počtové statistiky gravitačně čočkovaných optických oblouků u hvězdokup k určení horní meze kosmologické hustoty hmoty ve vesmíru. Statistika gravitačního čočkování způsobeného předními hvězdokupami kombinuje vlastnosti vývoje hvězdokup, který je citlivý na hustotu hmoty, a změny objemu, která je citlivá na kosmologickou konstantu. Nejistoty spojené s předpovídaným počtem čočkovacích událostí však v současnosti nedovolují rozlišit mezi plochými a otevřenými kosmologickými modely s i bez kosmologické konstanty. Přesto, po započtení známých chyb a za předpokladu, že hvězdokupy obecně mají jádřové poloměry temné hmoty řádu ~ 35 h^-1 kpc, zjišťujeme, že kosmologická hustota hmoty Omega_m je menší než 0,56 na hladině spolehlivosti 95 %. Takový poloměr jádra temné hmoty je v souladu s potenciály hvězdokup určenými nedávnými detailními numerickými inverzemi dat silného a slabého čočkování z obrazových pozorování. Pokud není žádný jádřový poloměr přítomen, zvýší se horní mez pro Omega_m na 0,62 (na hladině spolehlivosti 95 %). Odhadovaná horní mez pro Omega_m je v souladu s různými kosmologickými metodami, které naznačují nízkou hustotu hmoty ve vesmíru.
|
cs
|
This paper presents a manifold based Unscented Kalman Filter that applies a novel strategy for inertial, model-aiding and Acoustic Doppler Current Profiler (ADCP) measurement incorporation. The filter is capable of observing and utilizing the Earth rotation for heading estimation with a tactical grade IMU, and utilizes information from the vehicle model during DVL drop outs. The drag and thrust model-aiding accounts for the correlated nature of vehicle model parameter error by applying them as states in the filter. ADCP-aiding provides further information for the model-aiding in the case of DVL bottom-lock loss. Additionally this work was implemented using the MTK and ROCK framework in C++, and is capable of running in real-time on computing available on the FlatFish AUV. The IMU biases are estimated in a fully coupled approach in the navigation filter. Heading convergence is shown on a real-world data set. Further experiments show that the filter is capable of consistent positioning, and data denial validates the method for DVL dropouts due to very low or high altitude scenarios.
|
บทความนี้เสนอตัวกรองคัลแมนแบบไม่เป็นเชิงเส้นที่อิงจากแมนิโฟลด์ ซึ่งใช้กลยุทธ์ใหม่ในการรวมข้อมูลการวัดจากอุปกรณ์นำทางเชิงเฉื่อย ข้อมูลช่วยจากแบบจำลอง และข้อมูลจากเครื่องวัดความเร็วแบบอะคูสติกโดปเพลอร์ (Acoustic Doppler Current Profiler - ADCP) ตัวกรองดังกล่าวสามารถสังเกตและใช้ประโยชน์จากการหมุนของโลกเพื่อประมาณค่าทิศทางด้วยหน่วยวัดอินเนอร์เชียลระดับยุทธวิธี (tactical grade IMU) และใช้ข้อมูลจากแบบจำลองยานพาหนะในช่วงที่ไม่สามารถรับข้อมูลจากเครื่องวัดความเร็วแบบหุ่นยนต์ใต้น้ำ (DVL) ได้ การช่วยเหลือด้วยแบบจำลองแรงต้านและแรงขับนั้นคำนึงถึงลักษณะความสัมพันธ์ของความคลาดเคลื่อนพารามิเตอร์แบบจำลองยานพาหนะ โดยการนำพารามิเตอร์เหล่านี้มาใช้เป็นสถานะภายในตัวกรอง ส่วนการช่วยเหลือด้วย ADCP ให้ข้อมูลเพิ่มเติมสำหรับการช่วยเหลือด้วยแบบจำลองในกรณีที่สูญเสียการล็อกกับพื้นฐานของ DVL นอกจากนี้งานวิจัยนี้ยังได้ถูกนำไปใช้จริงด้วยเฟรมเวิร์ก MTK และ ROCK ในภาษา C++ และสามารถทำงานแบบเรียลไทม์บนระบบประมวลผลที่ติดตั้งอยู่บนยานพาหนะใต้น้ำอัตโนมัติ FlatFish ได้ โดยการประมาณค่าความเบี่ยงเบนของ IMU ทำในแนวทางที่เชื่อมโยงกันอย่างสมบูรณ์ภายในตัวกรองนำทาง การรวมตัวของค่าทิศทางแสดงให้เห็นจากชุดข้อมูลจริง การทดลองเพิ่มเติมแสดงให้เห็นว่าตัวกรองสามารถให้ตำแหน่งที่สอดคล้องกันอย่างต่อเนื่อง และการทดสอบในกรณีที่ข้อมูลถูกปฏิเสธยืนยันความเหมาะสมของวิธีการนี้สำหรับกรณีที่ DVL ไม่สามารถรับข้อมูลได้เนื่องจากความสูงจากระดับพื้นต่ำเกินไปหรือสูงเกินไป
|
th
|
Following Riley's work, for each 2-bridge link $K(r)$ of slope $r\in\QQ$ and an integer or a half-integer $n$ greater than 1, we introduce the {\it Heckoid orbifold $\orbs(r;n)$} and the {\it Heckoid group $\Hecke(r;n)=\pi_1(\orbs(r;n))$ of index $n$ for $K(r)$}. When $n$ is an integer, $\orbs(r;n)$ is called an {\it even} Heckoid orbifold; in this case, the underlying space is the exterior of $K(r)$, and the singular set is the lower tunnel of $K(r)$ with index $n$. The main purpose of this note is to announce answers to the following questions for even Heckoid orbifolds. (1) For an essential simple loop on a 4-punctured sphere $\PConway$ in $\orbs(r;n)$ determined by the 2-bridge sphere of $K(r)$, when is it null-homotopic in $\orbs(r;n)$? (2) For two distinct essential simple loops on $\PConway$, when are they homotopic in $\orbs(r;n)$? We also announce applications of these results to character varieties, McShane's identity, and epimorphisms from 2-bridge link groups onto Heckoid groups.
|
Riley'nin çalışmasından sonra, eğimi $r\in\QQ$ olan her 2-şeker bağlantısı $K(r)$ ve 1'den büyük bir tam sayı ya da yarı tam sayı $n$ için, $K(r)$ için {\it indeksi $n$ olan Heckoid orbifoldu $\orbs(r;n)$} ve {\it Heckoid grubu $\Hecke(r;n)=\pi_1(\orbs(r;n))$} kavramlarını tanıttık. $n$ bir tam sayı olduğunda, $\orbs(r;n)$'ye {\it çift} Heckoid orbifoldu denir; bu durumda, altta yatan uzay $K(r)$'nin dışıdır ve singular küme, indisi $n$ olan $K(r)$'nin alt tünelidir. Bu yazının temel amacı, çift Heckoid orbifoldları için aşağıdaki sorulara verilen yanıtları duyurmakdır. (1) $K(r)$ için 2-şeker küresiyle belirlenen, $\orbs(r;n)$ içindeki 4 delikli bir küre $\PConway$ üzerindeki bir temel basit döngü, $\orbs(r;n)$ içinde ne zaman null-homotopiktir? (2) $\PConway$ üzerindeki iki farklı temel basit döngü, $\orbs(r;n)$ içinde ne zaman homotopiktir? Ayrıca bu sonuçların karakter varyetelerine, McShane özdeşliğine ve 2-şeker bağlantı gruplarından Heckoid gruplarına giden epimorfizmalara uygulamalarını da duyuruyoruz.
|
tr
|
The Doppler dipole signal dominates the cosmic microwave background (CMB) anisotropy maps obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) mission, and plays a key role throughout the data processing. Previously, we discovered a timing asynchronism of -25.6ms between the timestamps of the spacecraft attitude and radiometer output in the original raw WMAP time-ordered data (TOD), which, if not corrected in following data processing, would generate an artificial quadrupole component (l=2) in recovered CMB maps (Liu, Xiong & Li 2010). Recently, Roukema (2010b) proves that there does exist a timing-offset-induced error corresponding to about -25.6ms in the WMAP calibrated TOD by studying the fluctuation variance per pixel in the temperature map recovered from the TOD as a function of assumed timing-offset. Here, we find evidence directly in the WMAP TOD for such an uncorrected timing error, possibly occurred in calculating the Doppler dipole signal during the WMAP team's TOD data processing. The amplitude is highly significant and is consistent with previous work. We also show that the uncorrected timing-offset can lead the WMAP CMB quadrupole to be substantially overestimated.
|
Tín hiệu lưỡng cực Doppler chi phối các bản đồ dị hướng bức xạ nền vi sóng vũ trụ (CMB) thu được từ sứ mệnh Wilkinson Microwave Anisotropy Probe (WMAP), và đóng vai trò then chốt trong toàn bộ quá trình xử lý dữ liệu. Trước đây, chúng tôi đã phát hiện ra một sự mất đồng bộ thời gian -25,6ms giữa các dấu thời gian của tư thế tàu vũ trụ và đầu ra của máy đo bức xạ trong dữ liệu thời gian gốc thô ban đầu của WMAP (TOD), mà nếu không được hiệu chỉnh trong quá trình xử lý dữ liệu tiếp theo, sẽ tạo ra một thành phần tứ cực giả (l=2) trong các bản đồ CMB phục hồi (Liu, Xiong & Li 2010). Gần đây, Roukema (2010b) chứng minh rằng thực sự tồn tại một sai số do lệch thời gian tương ứng khoảng -25,6ms trong dữ liệu TOD đã hiệu chuẩn của WMAP, bằng cách nghiên cứu phương sai dao động trên mỗi điểm ảnh trong bản đồ nhiệt độ phục hồi từ TOD như một hàm của độ lệch thời gian giả định. Ở đây, chúng tôi tìm thấy bằng chứng trực tiếp trong dữ liệu TOD của WMAP về lỗi lệch thời gian chưa được hiệu chỉnh như vậy, có thể xảy ra trong quá trình tính toán tín hiệu lưỡng cực Doppler trong xử lý dữ liệu TOD của nhóm WMAP. Biên độ của sai số này rất đáng kể và phù hợp với các nghiên cứu trước đó. Chúng tôi cũng chỉ ra rằng lỗi lệch thời gian chưa được hiệu chỉnh có thể dẫn đến việc ước tính quá cao đáng kể tứ cực CMB của WMAP.
|
vi
|
A growing number of learning methods are actually differentiable games whose players optimise multiple, interdependent objectives in parallel -- from GANs and intrinsic curiosity to multi-agent RL. Opponent shaping is a powerful approach to improve learning dynamics in these games, accounting for player influence on others' updates. Learning with Opponent-Learning Awareness (LOLA) is a recent algorithm that exploits this response and leads to cooperation in settings like the Iterated Prisoner's Dilemma. Although experimentally successful, we show that LOLA agents can exhibit 'arrogant' behaviour directly at odds with convergence. In fact, remarkably few algorithms have theoretical guarantees applying across all (n-player, non-convex) games. In this paper we present Stable Opponent Shaping (SOS), a new method that interpolates between LOLA and a stable variant named LookAhead. We prove that LookAhead converges locally to equilibria and avoids strict saddles in all differentiable games. SOS inherits these essential guarantees, while also shaping the learning of opponents and consistently either matching or outperforming LOLA experimentally.
|
越来越多的学习方法实际上是可微分博弈，其中参与者并行地优化多个相互依赖的目标——从生成对抗网络（GANs）和内在好奇心到多智能体强化学习均是如此。对手塑造是一种强大的方法，能够通过考虑参与者对其它参与者更新的影响，从而改善这些博弈中的学习动态。具有对手学习感知的学习算法（LOLA）是一种近期提出的算法，它利用了这种响应机制，并在诸如重复囚徒困境等场景中促成了合作行为。尽管LOLA在实验上取得了成功，但我们发现LOLA智能体可能表现出直接阻碍收敛的“傲慢”行为。事实上，极少有算法能在所有（n人、非凸）博弈中具备理论上的收敛保证。本文提出了一种名为稳定对手塑造（SOS）的新方法，该方法在LOLA与一种称为LookAhead的稳定变体之间进行插值。我们证明了LookAhead在所有可微分博弈中能够局部收敛到均衡点，并避免严格的鞍点。SOS继承了这些关键的理论保证，同时仍能对对手的学习进行塑造，并在实验中始终达到与LOLA相当或优于LOLA的表现。
|
zh
|
We present a study of analytic models of starless cores whose line profiles have ``infall asymmetry,'' or blue-skewed shapes indicative of contracting motions. We compare the ability of two types of analytical radiative transfer models to reproduce the line profiles and infall speeds of centrally condensed starless cores whose infall speeds are spatially constant and range between 0 and 0.2 km s-1. The model line profiles of HCO+ (J=1-0) and HCO+ (J=3-2) are produced by a self-consistent Monte Carlo radiative transfer code. The analytic models assume that the excitation temperature in the front of the cloud is either constant (``two-layer'' model) or increases inward as a linear function of optical depth (``hill'' model). Each analytic model is matched to the line profile by rapid least-squares fitting. The blue-asymmetric line profiles with two peaks, or with a blue shifted peak and a red shifted shoulder, can be well fit by the ``HILL5'' model (a five parameter version of the hill model), with an RMS error of 0.02 km s-1. A peak signal to noise ratio of at least 30 in the molecular line observations is required for performing these analytic radiative transfer fits to the line profiles.
|
Apresentamos um estudo de modelos analíticos de núcleos sem estrelas cujos perfis de linha apresentam "assimetria de infall", ou formas inclinadas para o azul indicativas de movimentos contráteis. Comparamos a capacidade de dois tipos de modelos analíticos de transferência radiativa em reproduzir os perfis de linha e as velocidades de infall de núcleos sem estrelas centralmente condensados cujas velocidades de infall são espacialmente constantes e variam entre 0 e 0,2 km s⁻¹. Os perfis de linha do modelo para HCO⁺ (J=1-0) e HCO⁺ (J=3-2) são gerados por um código autossistente de transferência radiativa de Monte Carlo. Os modelos analíticos assumem que a temperatura de excitação na frente da nuvem é constante (modelo de "duas camadas") ou aumenta para o interior como uma função linear da profundidade óptica (modelo de "colina"). Cada modelo analítico é ajustado ao perfil de linha por meio de ajuste rápido de mínimos quadrados. Os perfis de linha assimétricos para o azul com dois picos, ou com um pico deslocado para o azul e um ombro deslocado para o vermelho, podem ser bem ajustados pelo modelo "HILL5" (uma versão de cinco parâmetros do modelo de colina), com um erro RMS de 0,02 km s⁻¹. Uma relação sinal-ruído de pico de pelo menos 30 nas observações de linhas moleculares é necessária para realizar esses ajustes analíticos de transferência radiativa aos perfis de linha.
|
pt
|
Well-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are complied from the literature. Multiple optical emission components are extracted with power-law function fits to these lightcurves. We present a systematical analysis for statistical properties and their relations to prompt gamma-ray emission and X-ray afterglow for each component. We show that peak luminosity in the prompt and late flares are correlated and the evolution of the peak luminosity may signal the evolution of the accretion rate. No tight correlation between the shallow decay phase/plateau and prompt gamma-ray emission is found. Assuming that they are due to a long-lasting wind injected by a compact object, we show that the injected behavior favors the scenarios of a long-lasting wind after the main burst episode. The peak luminosity of the afterglow onset is tightly correlated with Eiso, and it is dimmer as peaking later. Assuming that the onset bump is due to the fireball deceleration by the external medium, we examine the Gamma_0-Eiso relation and find that it is confirmed with the current sample. Optical re-brightening is observed in 30 GRBs in our sample. It shares the same relation between the width and the peak time as found in the onset bump, but no clear correlation between the peak luminosity and Eiso as observed in the onset bumps is found. Although its peak luminosity also decays with time, the slope is much shallower than that of the onset peak. We get L t^{-1}_{p}$, being consistent with off-axis observations to an expanding external fireball in a wind-like circum medium. The late re-brightening may signal another jet component. Mixing of different emission components may be the reason for the observed chromatic breaks in different energy bands.
|
យើងបានប្រមូលផ្តុំពន្លឺដែលបានសង្កេតយ៉ាងល្អសម្រាប់ព្រឹត្តិការណ៍ផ្កាយហោះចេញពីកាំរស្មីហ្គាម៉ាចំនួន 146 (GRBs) ពីអត្ថបទដែលមានស្រាប់។ យើងបានដកយកគ្រឿងបង្ហាញពន្លឺជាច្រើនដោយប្រើអនុគមន៍ដុំថាមពល ដើម្បីធ្វើការត្រួតពិនិត្យលើកំណត់ត្រាទាំងនោះ។ យើងបានធ្វើការវិភាគប្រព័ន្ធសម្រាប់លក្ខណៈស្ថិតិ និងទំនាក់ទំនងរបស់វាទៅនឹងកាំរស្មីហ្គាម៉ាដំបូង និងកាំរស្មីអ៊ីកស៊ែរដែលនៅសល់សម្រាប់គ្រឿងបង្ហាញនីមួយៗ។ យើងបានបង្ហាញថា ភាពភ្លឺរលោងនៅពេលដំបូង និងការភ្លឺឡើងវិញនៅពេលក្រោយមានទំនាក់ទំនងគ្នា ហើយការវិវត្តនៃភាពភ្លឺរលោងអាចជាសញ្ញានៃការវិវត្តនៃអត្រាប្រមូលផ្តុំ។ យើងមិនបានរកឃើញទំនាក់ទំនងយ៉ាងជិតស្និតរវាងដំណាក់កាលធ្លាក់ចុះយឺត/ផ្ទៃរាបស្មើ និងកាំរស្មីហ្គាម៉ាដំបូងនោះទេ។ ដោយសន្មតថាវាកើតឡើងដោយសារខ្យល់ដែលបញ្ចេញយូរ ដែលបញ្ចេញដោយវត្ថុតូចមួយ យើងបានបង្ហាញថា ឥរិយាបថដែលបញ្ចេញនោះស័ក្តិសមជាមួយនឹងស្ថានភាពដែលខ្យល់បញ្ចេញយូរបន្ទាប់ពីព្រឹត្តិការណ៍ផ្កាយហោះដុំធំ។ ភាពភ្លឺរលោងនៃការចាប់ផ្តើមកាំរស្មីនៅសល់មានទំនាក់ទំនងយ៉ាងជិតស្និតជាមួយ Eiso ហើយវាភ្លឺតិចចុះកាន់តែយឺតកាន់តែភ្លឺ។ ដោយសន្មតថាការកើនឡើងភ្លឺនៅពេលចាប់ផ្តើមគឺដោយសារការយឺតរបស់ផ្កាយហោះដោយបរិស្ថានខាងក្រៅ យើងបានពិនិត្យមើលទំនាក់ទំនង Gamma_0-Eiso ហើយរកឃើញថាវាត្រូវបានបញ្ជាក់ដោយគំរូបច្ចុប្បន្ន។ ការភ្លឺឡើងវិញនៅពេលក្រោយត្រូវបានសង្កេតឃើញនៅក្នុង GRBs ចំនួន 30 ក្នុងគំរូរបស់យើង។ វាមានទំនាក់ទំនងដូចគ្នារវាងទទឹង និងពេលភ្លឺរលោងដូចដែលរកឃើញក្នុងការកើនឡើងភ្លឺនៅពេលចាប់ផ្តើម ប៉ុន្តែគ្មានទំនាក់ទំនងច្បាស់លាស់រវាងភាពភ្លឺរលោង និង Eiso ដូចដែលសង្កេតឃើញក្នុងការកើនឡើងភ្លឺនៅពេលចាប់ផ្តើមនោះទេ។ ទោះបីភាពភ្លឺរលោងរបស់វាក៏ធ្លាក់ចុះតាមពេលវេលាដែរ ប៉ុន្តែអូរធ្លាក់គឺរាបស្មើជាងអូរធ្លាក់នៃការកើនឡើងភ្លឺនៅពេលចាប់ផ្តើម។ យើងបានទទួលបាន L t^{-1}_{p} ដែលស័ក្តិសមជាមួយនឹងការសង្កេតពីក្រៅអ័ក្សទៅកាន់ផ្កាយហោះខាងក្រៅដែលកំពុងពង្រីកក្នុងបរិយាកាសដូចខ្យល់។ ការភ្លឺឡើងវិញនៅពេលក្រោយអាចជាសញ្ញានៃគ្រឿងបង្ហាញហ្សែតមួយទៀត។ ការលាយគ្នារវាងគ្រឿងបង្ហាញពន្លឺផ្សេងៗគ្នាអាចជាមូលហេតុនៃការបែកខ្ទរពណ៌ផ្សេងគ្នាដែលសង្កេតឃើញក្នុងខ្សែថាមពលផ្សេងៗគ្នា។
|
km
|
Ship detection in aerial images remains an active yet challenging task due to arbitrary object orientation and complex background from a bird's-eye perspective. Most of the existing methods rely on angular prediction or predefined anchor boxes, making these methods highly sensitive to unstable angular regression and excessive hyper-parameter setting. To address these issues, we replace the angular-based object encoding with an anchor-and-angle-free paradigm, and propose a novel detector deploying a center and four midpoints for encoding each oriented object, namely MidNet. MidNet designs a symmetrical deformable convolution customized for enhancing the midpoints of ships, then the center and midpoints for an identical ship are adaptively matched by predicting corresponding centripetal shift and matching radius. Finally, a concise analytical geometry algorithm is proposed to refine the centers and midpoints step-wisely for building precise oriented bounding boxes. On two public ship detection datasets, HRSC2016 and FGSD2021, MidNet outperforms the state-of-the-art detectors by achieving APs of 90.52% and 86.50%. Additionally, MidNet obtains competitive results in the ship detection of DOTA.
|
လေကြောင်းမှ ရရှိသော ဓာတ်ပုံများတွင် သင်္ဘောများကို စိစစ်ရှာဖွေခြင်းသည် အရာဝတ္ထုများ၏ လွတ်လပ်သော ဦးတည်မှုနှင့် ငှက်မျက်နှာပြင်မှ ရရှိသည့် ရှုပ်ထွေးသော နောက်ခံများကြောင့် လက်ရှိအချိန်တွင် ဆက်လက်လုပ်ဆောင်နေသော်လည်း စိန်ခေါ်မှုများစွာ ရှိနေဆဲဖြစ်သည်။ လက်ရှိရှိသည့် နည်းလမ်းအများစုသည် ထောင့်ပိုင်း ခန့်မှန်းခြင်း (angular prediction) သို့မဟုတ် ကြိုတင်သတ်မှတ်ထားသော အန်ကာဘောက် (anchor boxes) များကို အခြေခံထားပြီး ဤနည်းလမ်းများသည် မတည်ငြိမ်သော ထောင့်ပိုင်း ပြန်လည်တွက်ချက်မှု (angular regression) နှင့် အလွန်အကျွံ သတ်မှတ်ထားသည့် ဟိုက်ပါပါရာမီတာ (hyper-parameter) များကို အလွန်အမင်း အာရုံစိုက်မှုရှိနေသည်။ ဤပြဿနာများကို ဖြေရှင်းရန် ထောင့်ပေါ်အခြေခံသော အရာဝတ္ထု အကုဒ်သွင်းခြင်းကို အန်ကာနှင့် ထောင့်ကင်းသည့် ပုံစံ (anchor-and-angle-free paradigm) ဖြင့် အစားထိုးကာ ဗဟိုချက်တစ်ခုနှင့် အလျားလက်အလယ်ချက် လေးချက်ဖြင့် တစ်ခုချင်းစီကို အကုဒ်သွင်းသည့် သင်္ဘောအတွက် မူပိုင် စိစစ်ရှာဖွေသူ (detector) ကို ကြံစည်တီထွင်ခဲ့ပြီး ၎င်းကို MidNet ဟု ခေါ်သည်။ MidNet သည် သင်္ဘော၏ အလျားလက်အလယ်ချက်များကို မြှင့်တင်ရန် အထူးပြုထားသော အစီအစဥ်တကျ ပြောင်းလဲနိုင်သည့် ကွန်ဗြူလူးရှင်း (deformable convolution) ကို ဒီဇိုင်းထုတ်ထားပြီး သင်္ဘောတစ်စင်း၏ ဗဟိုနှင့် အလယ်ချက်များကို သက်ဆိုင်ရာ ဗဟိုမှစွန့်ပစ်အရွေ့ (centripetal shift) နှင့် ကိုက်ညီမှု အချင်းဝက် (matching radius) များကို ခန့်မှန်းကာ အလိုအလျောက် ကိုက်ညီစေသည်။ နောက်ဆုံးတွင် တိကျသော ဦးတည်မှုရှိသည့် စည်းကွပ်ဘောက် (oriented bounding boxes) များ တည်ဆောက်ရန် ဗဟိုနှင့် အလယ်ချက်များကို အဆင့်ဆင့် ပိုမိုတိကျအောင် ပြုလုပ်ပေးမည့် ရိုးရှင်းသော ခွဲခြမ်းစိတ်ဖြာသည့် ဂျီဩမေတြီ အယ်လ်ဂိုရီသမ် (analytical geometry algorithm) ကို ကြံစည်တီထွင်ခဲ့သည်။ ပြသနား သင်္ဘော စိစစ်ရှာဖွေမှု ဒေတာစုခြုံမှုနှစ်ခုဖြစ်သည့် HRSC2016 နှင့် FGSD2021 တို့တွင် MidNet သည် AP 90.52% နှင့် 86.50% ရရှိကာ လက်ရှိအကောင်းဆုံး စိစစ်ရှာဖွေသူများကို ကျော်လွန်သည်။ ထပ်မံ၍ MidNet သည် DOTA တွင် သင်္ဘော စိစစ်ရှာဖွေမှုတွင် ယှဉ်ပြိုင်နိုင်သည့် ရလဒ်များကို ရရှိခဲ့သည်။
|
my
|
Recent observation of supernovae type Ia show clearly that there is a large scale repulsive force in the Universe. Neither of the four known fundamental interactions can account for this repulsive force. Gravity is known to be the interaction responsible for the large scale structure and evolution of the Universe. The problem with gravity is that it gives rise to a force which is attractive only. Gravity theories, including General Relativity, deals with gravity as an attractive force. Although this is consistent with our experience in the solar system and other similar astrophysical systems, gravity theories fail to account for SN type Ia observation. So, we are in a real problem concerning the interpretation of these observation. This problem is only ten years old. In order to go out of this problematic situation, scientists have suggested the existence of a type of energy in the Universe that is responsible for the above mentioned repulsive force. They have given this type of energy the exotic term {\it "Dark Energy"}. Although this type of energy forms more than two thirds of the energetic contents of our Universe, its reasonable nature is missing in all gravity theories. The aim of the present work is to review the present status of the problem of dark energy. Also, to suggest a new geometric solution for this problem.
|
ការសង្កេតថ្មីៗលើផ្កាយហ៊្វង់ប្រភេទ Ia បានបង្ហាញយ៉ាងច្បាស់ថាមានកំលាំងដែលបណ្តេញចោលគ្នានៅកម្រិតធំនៅក្នុងចក្រវាឡ។ មិនមានអន្តរកម្មមូលដ្ឋានទាំងបួនដែលយើងស្គាល់អាចពន្យល់បាននូវកំលាងបណ្តេញចោលគ្នានេះទេ។ យើងស្គាល់ថាកំលាំងទំនាញគឺជាអន្តរកម្មដែលទទួលខុសត្រូវចំពោះរចនាសម្ព័ន្ធនិងដំណើរវិវត្តន៍នៅកម្រិតធំនៃចក្រវាឡ។ បញ្ហារបស់កំលាំងទំនាញគឺថាវាបង្កើតបានជាកំលាំងដែលទាញទៅរកគ្នាតែប៉ុណ្ណោះ។ ទ្រឹស្តីទំនាញ រួមទាំងទ្រឹស្តីទំនាញទូទៅ បានពិភាក្សាអំពីកំលាំងទំនាញថាជាកំលាំងទាញទៅរកគ្នា។ ទោះបីជាវាស៊ីសង្វាក់គ្នានឹងបទពិសោធន៍របស់យើងនៅក្នុងប្រព័ន្ធសុរិយាចក្រនិងប្រព័ន្ធផ្កាយអវកាសផ្សេងៗទៀតក៏ដោយ ក៏ទ្រឹស្តីទំនាញទាំងនោះបរាជ័យក្នុងការពន្យល់អំពីការសង្កេតផ្កាយហ៊្វង់ប្រភេទ Ia ដែរ។ ដូច្នេះ យើងកំពុងជួបនឹងបញ្ហាពិតប្រាកដមួយក្នុងការបកស្រាយអំពីការសង្កេតទាំងនោះ។ បញ្ហានេះមានអាយុតែដប់ឆ្នាំប៉ុណ្ណោះ។ ដើម្បីចេញពីស្ថានភាពបញ្ហានេះ អ្នកវិទ្យាសាស្ត្របានស្នើឱ្យមានថាមពលប្រភេទមួយនៅក្នុងចក្រវាឡ ដែលទទួលខុសត្រូវចំពោះកំលាំងបណ្តេញចោលគ្នាខាងលើ។ ពួកគេបានដាក់ឈ្មោះថាមពលប្រភេទនេះថា «ថាមពលងងឹត» {\it "Dark Energy"}។ ទោះបីជាថាមពលប្រភេទនេះបង្កើតបានជាច្រើនជាងពីរភាគបីនៃខ្លឹមសារថាមពលនៃចក្រវាឡយើងក៏ដោយ ក៏លក្ខណៈដែលអាចយល់បាននៃថាមពលនេះនៅខ្វះនៅក្នុងទ្រឹស្តីទំនាញទាំងអស់ដែរ។ គោលបំណងនៃការសិក្សាបច្ចុប្បន្ននេះគឺដើម្បីពិនិត្យឡើងវិញនូវស្ថានភាពបច្ចុប្បន្ននៃបញ្ហាថាមពលងងឹត។ ហើយផងដែរ ដើម្បីស្នើដំណោះស្រាយប្រភេទធរណីមាត្រថ្មីមួយសម្រាប់បញ្ហានេះ។
|
km
|
We discuss the prospects for detecting supersymmetric particles in variants of the minimal supersymmetric extension of the Standard Model (MSSM), in light of laboratory and cosmological constraints. We first assume that the lightest supersymmetric particle (LSP) is the lightest neutralino chi, and present scatter plots of the masses of the two lightest visible supersymmetric particles when the input scalar and gaugino masses are constrained to be universal (CMSSM), when the input Higgs scalar masses are non-universal (NUHM), and when the squark and slepton masses are also non-universal and the MSSM is regarded as a low-energy effective field theory valid up to the GUT scale (LEEST) or just up to 10 TeV (LEEST10). We then present similar plots in various scenarios when the LSP is the gravitino. We compare the prospects for detecting supersymmetry at linear colliders (LCs) of various energies, at the LHC, and as astrophysical dark matter. We find that, whilst a LC with a centre-of-mass energy E_{CM} <= 1000 GeV has some chance of discovering the lightest and next-to-lightest visible supersymmetric particles, E_{CM} >= 3000 GeV would be required to `guarantee' finding supersymmetry in the neutralino LSP scenarios studied, and an even higher E_{CM} might be required in certain gravitino dark matter scenarios. Direct dark matter experiments could explore part of the low-mass neutralino LSP region, but would not reveal all the models accessible to a low-energy LC.
|
Diskutujeme o možnostech detekce supersymetrických částic v rámci variant minimálního supersymetrického rozšíření standardního modelu (MSSM) s ohledem na laboratorní a kosmologické omezení. Nejprve předpokládáme, že nejlehčí supersymetrickou částicí (LSP) je nejlehčí neutrální částice chi, a prezentujeme bodové grafy hmotností dvou nejlehčích viditelných supersymetrických částic v případech, kdy vstupní skalární a gauginové hmotnosti jsou vázány na univerzálnost (CMSSM), kdy vstupní hmotnosti Higgsových skalárů jsou neuniverzální (NUHM) a kdy hmotnosti squarků a sleptonů jsou také neuniverzální a MSSM je považován za efektivní poleovou teorii platnou až po GUT stupnici (LEEST) nebo pouze po 10 TeV (LEEST10). Poté uvádíme podobné grafy pro různé scénáře, ve kterých je LSP gravitino. Porovnáváme možnosti detekce supersymetrie na lineárních urychlovačích (LC) různých energií, na LHC a jako astrofyzikální temnou hmotu. Zjistili jsme, že i když lineární urychlovač s energií v těžišťové soustavě E_{CM} <= 1000 GeV má určitou šanci objevit nejlehčí a druhou nejlehčí viditelnou supersymetrickou částici, je vyžadována energie E_{CM} >= 3000 GeV, aby bylo možné „zaručit“ objevení supersymetrie ve studovaných scénářích s neutrálním LSP, a v některých scénářích temné hmoty s gravitinem by mohla být vyžadována ještě vyšší energie E_{CM}. Přímé experimenty s temnou hmotou by mohly prozkoumat část oblasti s nízkou hmotností neutrálního LSP, ale neodhalily by všechny modely dostupné nízkoenergetickému LC.
|
cs
|
Deep neural networks (DNN) have achieved great success in the recommender systems (RS) domain. However, to achieve remarkable performance, DNN-based recommender models often require numerous parameters, which inevitably bring redundant neurons and weights, a phenomenon referred to as over-parameterization. In this paper, we plan to exploit such redundancy phenomena to improve the performance of RS. Specifically, we propose PCRec, a top-N item \underline{rec}ommendation framework that leverages collaborative training of two DNN-based recommender models with the same network structure, termed \underline{p}eer \underline{c}ollaboration. PCRec can reactivate and strengthen the unimportant (redundant) weights during training, which achieves higher prediction accuracy but maintains its original inference efficiency. To realize this, we first introduce two criteria to identify the importance of weights of a given recommender model. Then, we rejuvenate the unimportant weights by transplanting outside information (i.e., weights) from its peer network. After such an operation and retraining, the original recommender model is endowed with more representation capacity by possessing more functional model parameters. To show its generality, we instantiate PCRec by using three well-known recommender models. We conduct extensive experiments on three real-world datasets, and show that PCRec yields significantly better recommendations than its counterpart with the same model (parameter) size.
|
ເຄືອຂ່າຍປານໃຕ້ເລິກ (DNN) ໄດ້ບັນລຸຜົນສຳເລັດຢ່າງໃຫຍ່ຫຼວງໃນດ້ານລະບົບແນະນຳ (RS). ແຕ່ຢ່າງໃດກໍຕາມ, ເພື່ອບັນລຸຜົນງານທີ່ດີເດັ່ນ, ລຸ້ນ DNN ທີ່ໃຊ້ໃນລະບົບແນະນຳມັກຈະຕ້ອງການພາລາມິເຕີຈຳນວນຫຼວງຫຼາຍ, ເຊິ່ງເຮັດໃຫ້ເກີດເສັ້ນປະສາດ ແລະ ນ້ຳໜັກທີ່ຊ້ຳຊ້ອນ, ເປັນເຟື້ອນການທີ່ເອີ້ນວ່າ "ການມີພາລາມິເຕີຫຼາຍເກີນໄປ" (over-parameterization). ໃນບົດຄວາມນີ້, ພວກເຮົາມີແຜນທີ່ຈະນຳເອົາເຟື້ອນການຊ້ຳຊ້ອນນີ້ມາໃຊ້ເພື່ອປັບປຸງຜົນງານຂອງ RS. ໂດຍສະເພາະ, ພວກເຮົາຂໍເສີມຂໍ້ມູນ PCRec, ເຊິ່ງເປັນໂຄງຮ່າງການແນະນຳສິນຄ້າຕຳແໜ່ງ \underline{rec} ທຳອິດ N ທີ່ນຳໃຊ້ການຝຶກອົບຮົມຮ່ວມກັນຂອງລຸ້ນ DNN ສອງລຸ້ນທີ່ມີໂຄງສ້າງເຄືອຂ່າຍດຽວກັນ, ເຊິ່ງຖືກເອີ້ນວ່າ \underline{p}eer \underline{c}ollaboration. PCRec ສາມາດເປີດໃຊ້ຄືນ ແລະ ເຮັດໃຫ້ນ້ຳໜັກທີ່ບໍ່ສຳຄັນ (ຊ້ຳຊ້ອນ) ແຂງແຮງຂຶ້ນໃນຂະນະທີ່ຝຶກອົບຮົມ, ເຊິ່ງຊ່ວຍໃຫ້ຄວາມຖືກຕ້ອງໃນການຄາດຄະເນສູງຂຶ້ນ ແຕ່ຍັງຮັກສາປະສິດທິພາບໃນການຄຳນວນເຊັ່ນເກົ່າ. ເພື່ອບັນລຸເປົ້າໝາຍນີ້, ພວກເຮົານຳສະເໜີມາດຕະຖານສອງຢ່າງເພື່ອກຳນົດຄວາມສຳຄັນຂອງນ້ຳໜັກຂອງລຸ້ນແນະນຳໜຶ່ງ. ຕໍ່ມາ, ພວກເຮົາຟື້ນຟູນ້ຳໜັກທີ່ບໍ່ສຳຄັນໂດຍການຖ່າຍໂຍກຂໍ້ມູນຈາກພາຍນອກ (ນັ້ນກໍຄື, ນ້ຳໜັກ) ຈາກເຄືອຂ່າຍຄູ່ຮ່ວມງານຂອງມັນ. ຫຼັງຈາກດຳເນີນການດັ່ງກ່າວ ແລະ ຝຶກອົບຮົມຄືນ, ລຸ້ນແນະນຳດັ້ງເດີມຈະຖືກຕິດຕັ້ງຄວາມສາມາດໃນການແທນຂໍ້ມູນທີ່ດີຂຶ້ນໂດຍມີພາລາມິເຕີຂອງລຸ້ນທີ່ມີປະສິດທິພາບຫຼາຍຂຶ້ນ. ເພື່ອສະແດງໃຫ້ເຫັນຄວາມທົ່ວໄປຂອງມັນ, ພວກເຮົານຳ PCRec ມາໃຊ້ຈິງດ້ວຍລຸ້ນແນະນຳທີ່ຮູ້ຈັກດີສາມລຸ້ນ. ພວກເຮົາດຳເນີນການທົດລອງຢ່າງກວ້າງຂວາງໃນຂໍ້ມູນຈິງສາມຊຸດ, ແລະ ສະແດງໃຫ້ເຫັນວ່າ PCRec ສາມາດໃຫ້ຂໍ້ແນະນຳທີ່ດີກວ່າລຸ້ນທີ່ສອງທຽບເທົ່າກັນທີ່ມີຂະໜາດລຸ້ນ (ພາລາມິເຕີ) ດຽວກັນຢ່າງຫຼວງຫຼາຍ.
|
lo
|
Swift discovered GRB 050713A and slewed promptly to begin observing with its narrow field instruments 72.6 seconds after the burst onset, while the prompt gamma-ray emission was still detectable in the BAT. Simultaneous emission from two flares is detected in the BAT and XRT. This burst marks just the second time that the BAT and XRT have simultaneously detected emission from a burst and the first time that both instruments have produced a well sampled, simultaneous dataset covering multiple X-ray flares. The temporal rise and decay parameters of the flares are consistent with the internal shock mechanism. In addition to the Swift coverage of GRB 050713A, we report on the Konus-Wind (K-W) detection of the prompt emission in the energy range 18-1150 keV, an upper limiting GeV measurement of the prompt emission made by the MAGIC imaging atmospheric Cherenkov telescope and XMM-Newton observations of the afterglow. Simultaneous observation between Swift XRT and XMM-Newton produce consistent results, showing a break in the lightcurve at T+~15ks. Together, these four observatories provide unusually broad spectral coverage of the prompt emission and detailed X-ray follow-up of the afterglow for two weeks after the burst trigger. Simultaneous spectral fits of K-W with BAT and BAT with XRT data indicate that an absorbed broken powerlaw is often a better fit to GRB flares than a simple absorbed powerlaw. These spectral results together with the rapid temporal rise and decay of the flares suggest that flares are produced in internal shocks due to late time central engine activity.
|
Swift a découvert le GRB 050713A et s'est réorienté rapidement pour commencer l'observation avec ses instruments à champ étroit 72,6 secondes après le début du sursaut, alors que l'émission gamma prompte était encore détectable dans le BAT. Une émission simultanée provenant de deux sursauts est détectée dans le BAT et le XRT. Ce sursaut marque seulement la deuxième fois que le BAT et le XRT détectent simultanément une émission d'un sursaut, et la première fois que les deux instruments produisent un ensemble de données bien échantillonné et simultané couvrant plusieurs sursauts en rayons X. Les paramètres temporels de montée et de décroissance des sursauts sont compatibles avec le mécanisme de chocs internes. Outre les observations de Swift du GRB 050713A, nous rapportons la détection par Konus-Wind (K-W) de l'émission prompte dans la gamme d'énergie de 18 à 1150 keV, une mesure en limite supérieure dans le domaine GeV de l'émission prompte effectuée par le télescope à effet Tcherenkov atmosphérique imageant MAGIC, ainsi que des observations effectuées par XMM-Newton du rayonnement résiduel. L'observation simultanée par le XRT de Swift et par XMM-Newton donne des résultats cohérents, montrant une cassure dans la courbe de lumière à T+~15 ks. Ensemble, ces quatre observatoires offrent une couverture spectrale inhabituellement large de l'émission prompte et un suivi détaillé en rayons X du rayonnement résiduel pendant deux semaines après le déclenchement du sursaut. Des ajustements spectraux simultanés des données de K-W avec celles du BAT, et des données du BAT avec celles du XRT, indiquent qu'une loi de puissance brisée absorbée correspond souvent mieux aux sursauts de sursauts gamma qu'une simple loi de puissance absorbée. Ces résultats spectraux, combinés à la montée et à la décroissance temporelle rapide des sursauts, suggèrent que les sursauts sont produits par des chocs internes dus à une activité tardive du moteur central.
|
fr
|
The routing and wavelength assignment with protection is an important problem in telecommunications. Given an optical network and incoming connection requests, a commonly studied variant of the problem aims to grant maximum number of requests by assigning lightpaths at minimum network resource usage level, while ensuring the provided services remain functional in case of a single-link failure through dedicated path protection. We consider a practically relevant version where alternative lightpaths for requests are assumed to be given as a precomputed set, and show that it is NP-hard. We formulate the problem as an integer programming (IP) model, and also use it as a foundation to develop a novel quadratic unconstrained binary optimization (QUBO) model, which can be both directly solved by a state-of-the-art solver like GUROBI. We present necessary and sufficient conditions on objective function parameters to prioritize request granting objective over wavelength-link usage for both models, and a sufficient condition to ensure the exactness of the QUBO model. Moreover, we implement a problem-specific branch-and-cut algorithm for the IP model, and employ a new quantum-inspired technology, Digital Annealer (DA), for the QUBO model. We conduct computational experiments on a large suite of instances that are hard to optimally solve in order to assess the efficiency and efficacy of all of these approaches as well as a problem-specific heuristic. The results show that the emerging technology DA outperforms the considered established techniques coupled with GUROBI, in finding mostly significantly better or as good solutions in only two minutes compared to two hours of run time, whereas the problem-specific heuristic fails to be competitive.
|
Die Routing- und Wellenlängenzuweisung mit Schutz ist ein wichtiges Problem in der Telekommunikation. Gegeben ein optisches Netzwerk und eingehende Verbindungsanfragen, zielt eine häufig untersuchte Variante des Problems darauf ab, eine maximale Anzahl von Anfragen zu realisieren, indem Lichtpfade mit minimalem Ressourcenverbrauch im Netzwerk zugewiesen werden, wobei gleichzeitig sichergestellt wird, dass die bereitgestellten Dienste im Falle eines einzelnen Linkausfalls durch dedizierte Pfadschutzmaßnahmen weiterhin funktionsfähig bleiben. Wir betrachten eine praktisch relevante Version, bei der alternative Lichtpfade für Anfragen als vorausberechnete Menge gegeben sind, und zeigen, dass dieses Problem NP-schwer ist. Wir formulieren das Problem als ganzzahliges Programmierungsmodell (IP) und verwenden es zudem als Grundlage zur Entwicklung eines neuartigen quadratischen, unbeschränkten binären Optimierungsmodells (QUBO), das direkt durch einen modernen Löser wie GUROBI gelöst werden kann. Wir stellen notwendige und hinreichende Bedingungen an die Zielfunktionsparameter auf, um für beide Modelle das Ziel der Anfrageerfüllung gegenüber der Wellenlängen-Link-Nutzung zu priorisieren, sowie eine hinreichende Bedingung, um die Exaktheit des QUBO-Modells sicherzustellen. Darüber hinaus implementieren wir einen problemspezifischen Branch-and-Cut-Algorithmus für das IP-Modell und setzen eine neue, quanteninspirierte Technologie, den Digital Annealer (DA), für das QUBO-Modell ein. Wir führen umfangreiche Berechnungsexperimente auf einer großen Menge von Instanzen durch, die schwer optimal lösbar sind, um die Effizienz und Wirksamkeit all dieser Ansätze sowie einer problemspezifischen Heuristik zu bewerten. Die Ergebnisse zeigen, dass die neuartige Technologie DA die betrachteten etablierten Verfahren in Kombination mit GUROBI übertrifft, indem sie meist deutlich bessere oder gleichwertige Lösungen innerhalb von nur zwei Minuten im Vergleich zu zwei Stunden Rechenzeit findet, während die problemspezifische Heuristik nicht konkurrenzfähig ist.
|
de
|
Recently, researchers proposed various low-precision gradient compression, for efficient communication in large-scale distributed optimization. Based on these work, we try to reduce the communication complexity from a new direction. We pursue an ideal bijective mapping between two spaces of gradient distribution, so that the mapped gradient carries greater information entropy after the compression. In our setting, all servers should share a reference gradient in advance, and they communicate via the normalized gradients, which are the subtraction or quotient, between current gradients and the reference. To obtain a reference vector that yields a stronger signal-to-noise ratio, dynamically in each iteration, we extract and fuse information from the past trajectory in hindsight, and search for an optimal reference for compression. We name this to be the trajectory-based normalized gradients (TNG). It bridges the research from different societies, like coding, optimization, systems, and learning. It is easy to implement and can universally combine with existing algorithms. Our experiments on benchmarking hard non-convex functions, convex problems like logistic regression demonstrate that TNG is more compression-efficient for communication of distributed optimization of general functions.
|
最近、大規模分散最適化における効率的な通信のために、研究者らはさまざまな低精度勾配圧縮手法を提案した。これらの研究を基に、我々は通信複雑性を新たな方向から削減することを試みる。具体的には、勾配分布の二つの空間の間に理想的な全単射写像を追求し、圧縮後の勾配がより大きな情報エントロピーを持つようにする。我々の設定では、すべてのサーバーが事前に参照勾配を共有しており、現在の勾配と参照勾配との差分または商として得られる正規化勾配を介して通信を行う。より高い信号対雑音比をもたらす参照ベクトルを各反復で動的に得るために、過去の軌道から情報を後知恵的に抽出・融合し、圧縮に最適な参照を探索する。我々はこれを軌道に基づく正規化勾配（TNG）と呼ぶ。TNGは符号化、最適化、システム、学習といった異なる分野の研究を橋渡しする。実装が容易であり、既存のアルゴリズムと普遍的に組み合わせ可能である。ロジスティック回帰のような凸問題や、ベンチマークとなる困難な非凸関数に関する実験により、TNGが一般関数の分散最適化における通信に対してより圧縮効率的であることが示された。
|
ja
|
In computer vision, superpixels have been widely used as an effective way to reduce the number of image primitives for subsequent processing. But only a few attempts have been made to incorporate them into deep neural networks. One main reason is that the standard convolution operation is defined on regular grids and becomes inefficient when applied to superpixels. Inspired by an initialization strategy commonly adopted by traditional superpixel algorithms, we present a novel method that employs a simple fully convolutional network to predict superpixels on a regular image grid. Experimental results on benchmark datasets show that our method achieves state-of-the-art superpixel segmentation performance while running at about 50fps. Based on the predicted superpixels, we further develop a downsampling/upsampling scheme for deep networks with the goal of generating high-resolution outputs for dense prediction tasks. Specifically, we modify a popular network architecture for stereo matching to simultaneously predict superpixels and disparities. We show that improved disparity estimation accuracy can be obtained on public datasets.
|
В компьютерном зрении суперпиксели широко использовались как эффективный способ уменьшения количества примитивов изображения для последующей обработки. Однако лишь немногие попытки были предприняты для их интеграции в глубокие нейронные сети. Одна из основных причин заключается в том, что стандартная операция свёртки определена на регулярных сетках и становится неэффективной при применении к суперпикселям. Вдохновляясь стратегией инициализации, обычно применяемой в традиционных алгоритмах суперпикселей, мы предлагаем новый метод, использующий простую полностью свёрточную сеть для предсказания суперпикселей на регулярной сетке изображения. Экспериментальные результаты на тестовых наборах данных показывают, что наш метод достигает современного уровня производительности сегментации на суперпиксели, работая со скоростью около 50 кадров в секунду. На основе предсказанных суперпикселей мы дополнительно разрабатываем схему прореживания и интерполяции для глубоких сетей с целью получения выходных данных высокого разрешения для задач плотного предсказания. В частности, мы модифицируем популярную архитектуру сети для стереосопоставления, чтобы одновременно предсказывать суперпиксели и диспаранты. Мы показываем, что на публичных наборах данных можно достичь повышенной точности оценки диспарантов.
|
ru
|
Neutrino-dominated accretion flows (NDAFs) around rotating stellar-mass black holes (BHs) have been theorized as the central engine of relativistic jets launched in massive star core collapse events or compact star mergers. In this work, we calculate the electron neutrino/anti-neutrino spectra of NDAFs by fully taking into account the general relativistic effects, and investigate the effects of viewing angle, BH spin, and mass accretion rate on the results. We show that even though a typical NDAF has a neutrino luminosity lower than that of a typical supernova (SN), it can reach $10^{50}-10^{51}~{\rm erg~s^{-1}}$ peaking at $\sim 10$ MeV, making them potentially detectable with the upcoming sensitive MeV neutrino detectors if they are close enough to Earth. Based on the observed GRB event rate in the local universe and requiring that at least 3 neutrinos are detected to claim a detection, we estimate a detection rate up to $\sim$ (0.10-0.25) per century for GRB-related NDAFs by the Hyper-Kamiokande (Hyper-K) detector if one neglects neutrino oscillation. If one assumes that all Type Ib/c SNe have an engine-driven NDAF, the Hyper-K detection rate would be $\sim$ (1-3) per century. By considering neutrino oscillations, the detection rate may decrease by a factor of 2-3. Detecting one such event would establish the observational evidence of NDAFs in the universe.
|
ການໄຫຼຂອງອິນທະລີນິໂຕຣນໂດດເດັ່ນ (NDAFs) ລ້ອມຮອບຮູດຳມະສາດດາວ (BHs) ທີ່ກຳລັງຫມຸນ ໄດ້ຖືກທໍລະນີຕິກັນວ່າເປັນເຄື່ອງຈັກກາງທີ່ເຮັດໃຫ້ເກີດເປັນເຈັດສຳພັດສາຍສຳພັດທີ່ຖືກຍິງອອກຈາກເຫດການຫຍຸ້ງຍາດຂອງຫົວໃຈດາວມະສາດໃຫຍ່ ຫຼື ການລວມຕົວຂອງດາວທີ່ແອອັດ. ໃນວຽກງານນີ້, ພວກເຮົາຄິດໄລ່ສະເປັກຕຼັມນິໂຕຣນ/ອາຕິ-ນິໂຕຣນອິເລັກຕອນຂອງ NDAFs ໂດຍພິຈາລະນາຜົນກະທົບຂອງທໍລະນີສຳພັດທົ່ວໄປຢ່າງຄົບຖ້ວນ, ແລະ ສຶກສາຜົນກະທົບຂອງມຸມມອງ, ການຫມຸນຂອງຮູດຳ, ແລະ ອັດຕາການດູດກິນມະສາດຕໍ່ຜົນໄດ້ຮັບ. ພວກເຮົາສະແດງໃຫ້ເຫັນວ່າ ເຖິງແມ່ນວ່າ NDAF ທົ່ວໄປຈະມີພະລັງງານນິໂຕຣນຕໍ່າກວ່າພະລັງງານຂອງຊີ້ນລະເບີດດາວ (SN) ທົ່ວໄປ, ມັນກໍສາມາດບັນລຸໄດ້ເຖິງ $10^{50}-10^{51}~{\rm erg~s^{-1}}$ ໂດຍສູງສຸດຢູ່ທີ່ $\sim 10$ MeV, ເຮັດໃຫ້ມັນອາດຈະຖືກກວດພົບໄດ້ດ້ວຍເຄື່ອງກວດພົບນິໂຕຣນ MeV ທີ່ມີຄວາມລະອຽດສູງໃນອະນາຄົດ ຖ້າຫາກວ່າມັນຢູ່ໃກ້ພຽງພໍກັບໂລກ. ອີງຕາມອັດຕາເຫດການ GRB ທີ່ສັງເກດເຫັນໃນຈັກກະວານທ້ອງຖິ່ນ ແລະ ການກຳນົດວ່າຕ້ອງການຢ່າງໜ້ອຍ 3 ນິໂຕຣນທີ່ຖືກກວດພົບເພື່ອຢືນຢັນການກວດພົບ, ພວກເຮົາຄາດຄະເນອັດຕາການກວດພົບໄດ້ສູງສຸດເຖິງ $\sim$ (0.10-0.25) ຕໍ່ຮ້ອຍປີ ສຳລັບ NDAFs ທີ່ກ່ຽວຂ້ອງກັບ GRB ໂດຍເຄື່ອງກວດພົບ Hyper-Kamiokande (Hyper-K) ຖ້າຫາກບໍ່ພິຈາລະນາການເຄື່ອນທີ່ຂອງນິໂຕຣນ. ຖ້າຫາກວ່າເຮົາຖືວ່າດາວລະເບີດປະເພດ Ib/c ທຸກຊະນິດມີ NDAF ທີ່ຂັບເຄື່ອນດ້ວຍເຄື່ອງຈັກ, ອັດຕາການກວດພົບຂອງ Hyper-K ຈະເປັນ $\sim$ (1-3) ຕໍ່ຮ້ອຍປີ. ໂດຍການພິຈາລະນາການເຄື່ອນທີ່ຂອງນິໂຕຣນ, ອັດຕາການກວດພົບອາດຈະຫຼຸດລົງເຖິງ 2-3 ເທົ່າ. ການກວດພົບເຫດການດັ່ງກ່າວຈະເປັນການຢືນຢັນພົນລະເມືອງຂອງການມີຢູ່ຂອງ NDAFs ໃນຈັກກະວານ.
|
lo
|
The dynamical response of an Ising ferromagnet to a plane polarised standing magnetic field wave is modelled and studied here by Monte Carlo simulation in two dimensions. The amplitude of standing magnetic wave is modulated along the direction x. We have detected two main dynamical phases namely, pinned and oscillating spin clusters. Depending on the value of field amplitude the system is found to undergo a phase transition from oscillating spin cluster to pinned as the system is cooled down. The time averaged magnetisation over a full cycle of magnetic field oscillations is defined as the dynamic order parameter. The transition is detected by studying the temperature dependences of the variance of the dynamic order parameter, the derivative of the dynamic order parameter and the dynamic specific heat. The dependence of the transition temperature on the magnetic field amplitude and on the wavelength of the magnetic field wave is studied at a single frequency. A comprehensive phase boundary is drawn in the plane described by the temperature and field amplitude for two different wavelengths of the magnetic wave. The variation of instantaneous line magnetisation during a period of magnetic field oscillation for standing wave mode is compared to those for the propagating wave mode. Also the probability that a spin at any site, flips, is calculated. The above mentioned variations and the probability of spin flip clearly distinguish between the dynamical phases formed by propagating magnetic wave and by standing magnetic wave in an Ising ferromagnet.
|
يتم نمذجة ودراسة الاستجابة الديناميكية لمغناطيس حديدي من نوع إيسينغ لتموج مغناطيسي واقف مستوٍ مستقطب باستخدام محاكاة مونت كارلو في بعدين. يتم تعديل سعة التموج المغناطيسي الواقف على امتداد الاتجاه x. وقد تم الكشف عن مرحلتين ديناميكيتين رئيسيتين هما: تجمعات لحظات مغناطيسية مثبتة وتجمعات لحظات مغناطيسية متذبذبة. وحسب قيمة سعة الحقل، يتبين أن النظام يمر بتحول طوري من تجمع لحظات مغناطيسية متذبذب إلى تجمع مثبت عند تبريده. ويُعرف متوسط المغناطيسية الزمني خلال دورة كاملة من تذبذبات الحقل المغناطيسي بوصفه معامل الطلب الديناميكي. ويتم الكشف عن التحول من خلال دراسة تبعية درجة الحرارة للتباين في معامل الطلب الديناميكي، ومشتقة معامل الطلب الديناميكي، والسعة الحرارية الديناميكية. وتمت دراسة تبعية درجة حرارة التحول لسعة الحقل المغناطيسي وطول موجة التموج المغناطيسي عند تردد واحد. ويتم رسم حدود طورية شاملة في المستوى المحدد بواسطة درجة الحرارة وسعة الحقل، وذلك لطولَي موجتين مختلفين للتموج المغناطيسي. وتتم مقارنة تغيرات المغناطيسية الخطية اللحظية خلال فترة تذبذب الحقل المغناطيسي لنمط التموج الواقف مع تلك الخاصة بنمط التموج المتنقل. كما يتم حساب احتمال قلب اللحظة المغناطيسية عند أي موقع. وتكشف التغيرات المذكورة أعلاه واحتمال قلب اللحظة المغناطيسية بوضوح الفرق بين المرحلتين الديناميكية الناتجتين عن التموج المغناطيسي المتنقل والتموج المغناطيسي الواقف في مغناطيس حديدي من نوع إيسينغ.
|
ar
|
Poisson Voronoi tessellations have been used in modeling many types of systems across different sciences, from geography and astronomy to telecommunications. The existing literature on the statistical properties of Poisson Voronoi cells is vast, however, little is known about the properties of Voronoi cells located close to the boundaries of a compact domain. In a domain with boundaries, some Voronoi cells would be naturally clipped by the boundary, and the cell area falling inside the deployment domain would have different statistical properties as compared to those of non-clipped Voronoi cells located in the bulk of the domain. In this paper, we consider the planar Voronoi tessellation induced by a homogeneous Poisson point process of intensity $\lambda\!>\!0$ in a quadrant, where the two half-axes represent boundaries. We show that the mean cell area is less than $\lambda^{-1}$ when the seed is located exactly at the boundary, and it can be larger than $\lambda^{-1}$ when the seed lies close to the boundary. In addition, we calculate the second moment of cell area at two locations for the seed: (i) at the corner of a quadrant, and (ii) at the boundary of the half-plane. We illustrate that the two-parameter Gamma distribution, with location-dependent parameters calculated using the method of moments, can be of use in approximating the distribution of cell area. As a potential application, we use the Gamma approximations to study the degree distribution for secure connectivity in wireless sensor networks deployed over a domain with boundaries.
|
ការបំបែកប៉ូអ៊ីស៊ើន វ៉ូរ៉ូណូយ (Poisson Voronoi tessellations) ត្រូវបានប្រើក្នុងការគំរូប្រព័ន្ធច្រើនប្រភេទនៅក្នុងវិទ្យាសាស្ត្រផ្សេងៗ ចាប់ពីភូមិសាស្ត្រ និងតារាសាស្ត្រ រហូតដល់ទូរគមនាគមន៍។ ប្រសាសន៍ស្រាវជ្រាវដែលមានស្រាប់អំពីលក្ខណៈស្ថិតិនៃកោសិកាវ៉ូរ៉ូណូយប៉ូអ៊ីស៊ើនគឺមានច្រើនសន្ធឹកសន្ធាប់ ទោះជាយ៉ាងណាក៏ដោយ ក៏មានការស្គាល់តិចតួចណាស់អំពីលក្ខណៈនៃកោសិកាវ៉ូរ៉ូណូយដែលស្ថិតនៅជិតដែនកំណត់នៃដែនដីដែលមានដែនកំណត់។ នៅក្នុងដែនដីដែលមានដែនកំណត់ កោសិកាវ៉ូរ៉ូណូយខ្លះនឹងត្រូវបានកាត់បន្ថយដោយដែនកំណត់ ហើយផ្ទៃកោសិកាដែលស្ថិតនៅខាងក្នុងដែនដីនឹងមានលក្ខណៈស្ថិតិខុសពីកោសិកាវ៉ូរ៉ូណូយដែលមិនត្រូវបានកាត់បន្ថយ ដែលស្ថិតនៅក្នុងផ្នែកខាងក្នុងនៃដែនដី។ នៅក្នុងការស្រាវជ្រាវនេះ យើងពិចារណាលើការបំបែកវ៉ូរ៉ូណូយលើផ្ទៃប្លង់ដែលបង្កឡើងដោយដំណើរការចំណុចប៉ូអ៊ីស៊ើនដែលមានភាពស្មើគ្នានៃកម្លាំង $\lambda\!>\!0$ នៅក្នុងចតុកោណ ដែលអ័ក្សពីរកន្លះតំណាងអោយដែនកំណត់។ យើងបង្ហាញថា ផ្ទៃកោសិកាមធ្យមគឺតិចជាង $\lambda^{-1}$ នៅពេលដែលគ្រាប់ពូជស្ថិតនៅត្រង់ដែនកំណត់ ហើយវាអាចធំជាង $\lambda^{-1}$ នៅពេលដែលគ្រាប់ពូជស្ថិតនៅជិតដែនកំណត់។ លើសពីនេះ យើងគណនាម៉ូម៉ង់ទីពីរនៃផ្ទៃកោសិកានៅត្រង់ទីតាំងពីរសម្រាប់គ្រាប់ពូជ៖ (i) នៅជ្រុងនៃចតុកោណ និង (ii) នៅដែនកំណត់នៃប្លង់កន្លះ។ យើងបង្ហាញថា ច្បាប់ហ្គាំម៉ាពីរប៉ារ៉ាម៉ែត្រ ដែលមានប៉ារ៉ាម៉ែត្រអាស្រ័យទីតាំងដែលគណនាដោយវិធីសាស្ត្រនៃម៉ូម៉ង់ អាចប្រើបានក្នុងការប៉ាន់ស្មានច្បាប់នៃផ្ទៃកោសិកា។ ជាកម្មវិធីសក្តានុពល យើងប្រើការប៉ាន់ស្មានហ្គាំម៉ាដើម្បីសិក្សាច្បាប់នៃដឺក្រេសម្រាប់ភាពតភ្ជាប់ដែលមានសុវត្ថិភាពនៅក្នុងបណ្តាញអំពើរាវវាលដែលត្រូវបានដំឡើងលើដែនដីដែលមានដែនកំណត់។
|
km
|
Natural populations often show enhanced genetic drift consistent with a strong skew in their offspring number distribution. The skew arises because the variability of family sizes is either inherently strong or amplified by population expansions, leading to so-called `jackpot' events. The resulting allele frequency fluctuations are large and, therefore, challenge standard models of population genetics, which assume sufficiently narrow offspring distributions. While the neutral dynamics backward in time can be readily analyzed using coalescent approaches, we still know little about the effect of broad offspring distributions on the dynamics forward in time, especially with selection. Here, we employ an exact asymptotic analysis combined with a scaling hypothesis to demonstrate that over-dispersed frequency trajectories emerge from the competition of conventional forces, such as selection or mutations, with an emerging time-dependent sampling bias against the minor allele. The sampling bias arises from the characteristic time-dependence of the largest sampled family size within each allelic type. Using this insight, we establish simple scaling relations for allele frequency fluctuations, fixation probabilities, extinction times, and the site frequency spectra that arise when offspring numbers are distributed according to a power law $~n^{-(1+\alpha)}$. To demonstrate that this coarse-grained model captures a wide variety of non-equilibrium dynamics, we validate our results in traveling waves, where the phenomenon of 'gene surfing' can produce any exponent $1<\alpha <2$. We argue that the concept of a dynamic sampling bias is useful generally to develop both intuition and statistical tests for the unusual dynamics of populations with skewed offspring distributions, which can confound commonly used tests for selection or demographic history.
|
自然种群常常表现出增强的遗传漂变，这与后代数量分布的高度偏斜一致。这种偏斜源于家族大小的变异性本身较强，或因种群扩张而被放大，从而导致所谓的“ jackpot”事件。由此产生的等位基因频率波动较大，因而对标准的群体遗传学模型提出了挑战，因为这些模型假设后代分布足够集中。虽然可以通过溯祖方法方便地分析时间倒向的中性动力学，但我们对广泛后代分布正向时间动力学的影响仍知之甚少，尤其是在存在选择的情况下。本文采用精确的渐近分析结合标度假设，证明了过度离散的频率轨迹源于传统力量（如选择或突变）与一种针对稀有等位基因的、随时间变化的抽样偏差之间的竞争。这种抽样偏差源自每种等位类型中最大抽样家族大小所具有的特征性时间依赖性。基于这一认识，我们建立了等位基因频率波动、固定概率、灭绝时间以及位点频率谱的简单标度关系，适用于后代数量服从幂律分布 $~n^{-(1+\alpha)}$ 的情形。为证明该粗粒化模型能够捕捉多种非平衡动力学行为，我们以行进波为例进行了验证，其中“基因冲浪”现象可产生任意指数 $1<\alpha <2$。我们认为，动态抽样偏差这一概念具有普遍意义，有助于建立对后代分布偏斜种群异常动力学的直观理解，并为开发相应的统计检验方法提供基础，而这类种群的动力学可能干扰常用的选择或种群历史推断检验。
|
zh
|
Let $G$ be a connected semisimple group over ${\Bbb Q}$. Given a maximal compact subgroup $K\subset G({\Bbb R})$ such that $X=G({\Bbb R})/K$ is a Hermitian symmetric domain, and a convenient arithmetic subgroup $\Gamma\subset G({\Bbb Q})$, one constructs a (connected) Shimura variety $S=S(\Gamma)=\Gamma\backslash X$. If $H\subset G$ is a connected semisimple subgroup such that $H({\Bbb R})\cap K$ is maximal compact, then $Y=H({\Bbb R})/K$ is a Hermitian symmetric subdomain of $X$. For each $g\in G({\Bbb Q})$ one can construct a connected Shimura variety $S(H,g)=(H({\Bbb Q})\cap g^{-1}\Gamma g)\backslash Y$ and a natural holomorphic map $j_g \colon S(H,g)\to S$ induced by the map $H({\Bbb A})\to G({\Bbb A}), h\mapsto gh$. Let us assume that $G$ is anisotropic, which implies that $S$ and $S(H,g)$ are compact. Then, for each positive integer $k$, the map $j_g$ induces a restriction map $$R_g \colon H^{k}(S, {\Bbb C})\to H^{k}(S(H,g), {\Bbb C}).$$ In this paper we focus on classical Hermitian domains and give explicit criterions for the injectivity of the product of the maps $R_g$ (for $g$ running through $G({\Bbb Q})$) when restricted to the strongly primitive (in the sense of Vogan and Zuckerman) part of the cohomology. In the holomorphic case we recover previous results of Clozel and Venkataramana. We also derive applications of our results to the proofs of new cases of the Hodge conjecture and of new results on the vanishing of the cohomology of some particular Shimura variety.
|
ধরা যাক, $G$ হল ${\Bbb Q}$-এর উপর একটি সংযুক্ত অর্ধসরল গ্রুপ। একটি সর্বোচ্চ সংকুচিত উপগ্রুপ $K\subset G({\Bbb R})$ দেওয়া হল যাতে $X=G({\Bbb R})/K$ একটি হার্মিটিয়ান প্রতিসাম্য ডোমেন হয়, এবং একটি উপযুক্ত সংখ্যাতাত্ত্বিক উপগ্রুপ $\Gamma\subset G({\Bbb Q})$, একটি (সংযুক্ত) শিমুরা বহুভুজ $S=S(\Gamma)=\Gamma\backslash X$ গঠন করা হয়। যদি $H\subset G$ একটি সংযুক্ত অর্ধসরল উপগ্রুপ হয় যাতে $H({\Bbb R})\cap K$ সর্বোচ্চ সংকুচিত হয়, তবে $Y=H({\Bbb R})/K$ হবে $X$-এর একটি হার্মিটিয়ান প্রতিসাম্য উপডোমেন। প্রতিটি $g\in G({\Bbb Q})$-এর জন্য একটি সংযুক্ত শিমুরা বহুভুজ $S(H,g)=(H({\Bbb Q})\cap g^{-1}\Gamma g)\backslash Y$ এবং একটি স্বাভাবিক হলোমরফিক চিত্র $j_g \colon S(H,g)\to S$ গঠন করা যায় যা চিত্র $H({\Bbb A})\to G({\Bbb A}), h\mapsto gh$ থেকে উদ্ভূত হয়। ধরা যাক, $G$ একটি অ্যানাইসোট্রপিক, যা নির্দেশ করে যে $S$ এবং $S(H,g)$ সংকুচিত। তবে, প্রতিটি ধনাত্মক পূর্ণসংখ্যা $k$-এর জন্য, চিত্র $j_g$ একটি সীমাবদ্ধতা চিত্র নির্দেশ করে $$R_g \colon H^{k}(S, {\Bbb C})\to H^{k}(S(H,g), {\Bbb C}).$$ এই গবেষণাপত্রে আমরা ক্লাসিক্যাল হার্মিটিয়ান ডোমেনগুলির উপর মনোনিবেশ করি এবং সমষ্টিগত সময়ের শক্তিশালী প্রাথমিক (ভোগান ও জাকারম্যানের অর্থে) অংশে সীমাবদ্ধ হওয়ার সময় $R_g$ চিত্রগুলির (যেখানে $g$ $G({\Bbb Q})$-এর মধ্যে পরিবর্তিত হয়) গুণফলের এক-এক চিত্র হওয়ার জন্য স্পষ্ট শর্ত দিই। হলোমরফিক ক্ষেত্রে আমরা ক্লোজেল এবং বেঙ্কটারামানার পূর্ববর্তী ফলাফলগুলি পুনরুদ্ধার করি। আমরা হডজ অনুমানের নতুন ক্ষেত্রগুলির প্রমাণ এবং কিছু নির্দিষ্ট শিমুরা বহুভুজের সমষ্টিগত সময়ের অদৃশ্য হওয়া সম্পর্কিত নতুন ফলাফলগুলিতে আমাদের ফলাফলের প্রয়োগগুলিও উপস্থাপন করি।
|
bn
|
An integer polynomial $p$ of $n$ variables is called a \emph{threshold gate} for a Boolean function $f$ of $n$ variables if for all $x \in \zoon$ $f(x)=1$ if and only if $p(x)\geq 0$. The \emph{weight} of a threshold gate is the sum of its absolute values. In this paper we study how large a weight might be needed if we fix some function and some threshold degree. We prove $2^{\Omega(2^{2n/5})}$ lower bound on this value. The best previous bound was $2^{\Omega(2^{n/8})}$ (Podolskii, 2009). In addition we present substantially simpler proof of the weaker $2^{\Omega(2^{n/4})}$ lower bound. This proof is conceptually similar to other proofs of the bounds on weights of nonlinear threshold gates, but avoids a lot of technical details arising in other proofs. We hope that this proof will help to show the ideas behind the construction used to prove these lower bounds.
|
พหุนามจำนวนเต็ม \( p \) ของตัวแปร \( n \) ตัวเรียกว่า \emph{เกตขีดจำกัด} (threshold gate) สำหรับฟังก์ชันบูลีน \( f \) ของตัวแปร \( n \) ตัว ถ้าสำหรับทุก \( x \in \{0,1\}^n \) จะได้ว่า \( f(x)=1 \) ก็ต่อเมื่อ \( p(x)\geq 0 \) \emph{น้ำหนัก} ของเกตขีดจำกัดคือผลรวมของค่าสัมบูรณ์ของสัมประสิทธิ์ทั้งหมด ในงานวิจัยนี้ เราศึกษาถึงขนาดของน้ำหนักที่อาจจำเป็นต้องใช้ ถ้าเรากำหนดฟังก์ชันและดีกรีขีดจำกัดบางอย่างไว้ล่วงหน้า เราพิสูจน์ว่าค่าดังกล่าวมีขอบเขตล่างที่ \( 2^{\Omega(2^{2n/5})} \) ขอบเขตที่ดีที่สุดก่อนหน้านี้คือ \( 2^{\Omega(2^{n/8})} \) (Podolskii, 2009) นอกจากนี้ เรายังนำเสนอการพิสูจน์ที่ง่ายกว่าอย่างมีนัยสำคัญสำหรับขอบเขตล่างที่อ่อนกว่า \( 2^{\Omega(2^{n/4})} \) การพิสูจน์นี้มีแนวคิดพื้นฐานคล้ายคลึงกับการพิสูจน์อื่น ๆ ที่เกี่ยวกับขอบเขตล่างของน้ำหนักของเกตขีดจำกัดเชิงไม่เชิงเส้น แต่หลีกเลี่ยงรายละเอียดทางเทคนิคจำนวนมากที่ปรากฏในการพิสูจน์อื่น ๆ เราหวังว่าการพิสูจน์นี้จะช่วยให้เห็นแนวคิดเบื้องหลังการสร้างที่ใช้ในการพิสูจน์ขอบเขตล่างเหล่านี้ได้ชัดเจนยิ่งขึ้น
|
th
|
Swift discovered GRB 050713A and slewed promptly to begin observing with its narrow field instruments 72.6 seconds after the burst onset, while the prompt gamma-ray emission was still detectable in the BAT. Simultaneous emission from two flares is detected in the BAT and XRT. This burst marks just the second time that the BAT and XRT have simultaneously detected emission from a burst and the first time that both instruments have produced a well sampled, simultaneous dataset covering multiple X-ray flares. The temporal rise and decay parameters of the flares are consistent with the internal shock mechanism. In addition to the Swift coverage of GRB 050713A, we report on the Konus-Wind (K-W) detection of the prompt emission in the energy range 18-1150 keV, an upper limiting GeV measurement of the prompt emission made by the MAGIC imaging atmospheric Cherenkov telescope and XMM-Newton observations of the afterglow. Simultaneous observation between Swift XRT and XMM-Newton produce consistent results, showing a break in the lightcurve at T+~15ks. Together, these four observatories provide unusually broad spectral coverage of the prompt emission and detailed X-ray follow-up of the afterglow for two weeks after the burst trigger. Simultaneous spectral fits of K-W with BAT and BAT with XRT data indicate that an absorbed broken powerlaw is often a better fit to GRB flares than a simple absorbed powerlaw. These spectral results together with the rapid temporal rise and decay of the flares suggest that flares are produced in internal shocks due to late time central engine activity.
|
Swift entdeckte GRB 050713A und richtete seine engwinkligen Instrumente 72,6 Sekunden nach Beginn des Ausbruchs prompt aus, während die anfängliche Gammastrahlung noch im BAT nachweisbar war. Gleichzeitige Emission aus zwei Flares wurde im BAT und XRT detektiert. Dieser Ausbruch stellt erst den zweiten Fall dar, bei dem BAT und XRT gleichzeitig Emission eines Ausbruchs nachweisen konnten, und ist der erste Fall, bei dem beide Instrumente einen gut abgetasteten, simultanen Datensatz erfassten, der mehrere Röntgen-Flares abdeckt. Die zeitlichen Anstiegs- und Abklingparameter der Flares stimmen mit dem Mechanismus interner Schocks überein. Zusätzlich zur Beobachtung von GRB 050713A durch Swift berichten wir über die Detektion der anfänglichen Emission durch Konus-Wind (K-W) im Energiebereich von 18–1150 keV, eine obere Grenzbestimmung der GeV-Emission durch das bildgebende atmosphärische Cherenkov-Teleskop MAGIC sowie Beobachtungen des Nachglows durch XMM-Newton. Gleichzeitige Beobachtungen von Swift XRT und XMM-Newton liefern konsistente Ergebnisse und zeigen einen Bruch in der Lichtkurve bei T+~15 ks. Gemeinsam bieten diese vier Observatorien eine ungewöhnlich breite spektrale Abdeckung der anfänglichen Emission sowie eine detaillierte röntgenastronomische Nachbeobachtung des Nachglows für zwei Wochen nach dem Auslösen des Ausbruchs. Gleichzeitige spektrale Anpassungen von K-W mit BAT- und BAT mit XRT-Daten zeigen, dass ein absorbiertes gebrochenes Potenzgesetz häufig eine bessere Anpassung an GRB-Flares liefert als ein einfaches absorbiertes Potenzgesetz. Diese spektralen Ergebnisse zusammen mit dem schnellen zeitlichen Anstieg und Abfall der Flares deuten darauf hin, dass die Flares durch interne Schocks infolge spätzeitiger Aktivität des zentralen Motors erzeugt werden.
|
de
|
To bridge the gap between the capabilities of the state-of-the-art in factoid question answering (QA) and what users ask, we need large datasets of real user questions that capture the various question phenomena users are interested in, and the diverse ways in which these questions are formulated. We introduce ComQA, a large dataset of real user questions that exhibit different challenging aspects such as compositionality, temporal reasoning, and comparisons. ComQA questions come from the WikiAnswers community QA platform, which typically contains questions that are not satisfactorily answerable by existing search engine technology. Through a large crowdsourcing effort, we clean the question dataset, group questions into paraphrase clusters, and annotate clusters with their answers. ComQA contains 11,214 questions grouped into 4,834 paraphrase clusters. We detail the process of constructing ComQA, including the measures taken to ensure its high quality while making effective use of crowdsourcing. We also present an extensive analysis of the dataset and the results achieved by state-of-the-art systems on ComQA, demonstrating that our dataset can be a driver of future research on QA.
|
حقیقت پر مبنی سوالات کے جواب دینے (QA) کی موجودہ صلاحیتوں اور صارفین کے سوالات کے درمیان فرق کو پُر کرنے کے لیے، ہمیں حقیقی صارفین کے سوالات کے بڑے ڈیٹا سیٹ کی ضرورت ہے جو ان مختلف سوالاتی پہلوؤں کو ظاہر کریں جن میں صارفین دلچسپی رکھتے ہیں، اور ان سوالات کے مختلف اظہار کو بھی ظاہر کریں۔ ہم کوم کیو اے (ComQA) متعارف کراتے ہیں، جو حقیقی صارفین کے سوالات کا ایک بڑا ڈیٹا سیٹ ہے جس میں ترکیبیت، وقت کے حوالے سے استدلال، اور موازنہ جیسے مختلف چیلنجنگ پہلو شامل ہیں۔ کوم کیو اے کے سوالات ویکی آنسرز کمیونٹی کیو اے پلیٹ فارم سے آتے ہیں، جس میں عام طور پر وہ سوالات ہوتے ہیں جن کے جوابات موجودہ سرچ انجن ٹیکنالوجی کے ذریعے مطمئن انداز میں نہیں دیے جا سکتے۔ بڑے پیمانے پر کراؤڈ سورسنگ کے ذریعے، ہم سوالات کے ڈیٹا سیٹ کی صفائی کرتے ہیں، سوالات کو مترادف کلستروں میں گروپ کرتے ہیں، اور کلستروں کو جوابات کے ساتھ نوٹ کرتے ہیں۔ کوم کیو اے میں 11,214 سوالات 4,834 مترادف کلستروں میں گروپ کیے گئے ہیں۔ ہم کوم کیو اے کی تعمیر کے عمل کی تفصیل بیان کرتے ہیں، بشمول ان اقدامات کی وضاحت جو اعلیٰ معیار کو یقینی بنانے کے لیے کیے گئے جبکہ کراؤڈ سورسنگ کا موثر استعمال کیا گیا۔ ہم ڈیٹا سیٹ کا وسیع تجزیہ بھی پیش کرتے ہیں اور کوم کیو اے پر موجودہ دور کے نظاموں کی کارکردگی کے نتائج دیتے ہیں، جو ظاہر کرتے ہیں کہ ہمارا ڈیٹا سیٹ مستقبل کی کیو اے تحقیق کو آگے بڑھانے کا ذریعہ بن سکتا ہے۔
|
ur
|
The Broensted and Lowry acid base theory is based on the capacity of proton donation or acceptance (in the presence or absence of a solvent) whereas the Lewis acid base theory is based on the propensity of electron pair acceptance or donation. We explore through DFT calculation the obvious question whether these two theories are in conformity with each other. We use pKa as the descriptor for the Broensted and Lowry acidity. The DFT descriptors like ionization potential, electron affinity, electronegativity, hardness and global electrophilicity are computed for 58 organic and inorganic acids. The fractional electron transfer, del(N) and the associated energy change, del(E) for the reaction of these acids with trimethyl amine (a strong base) are used as the possible descriptors for the Lewis acidity. A near exponential decrease in del(N) and (-del(E)) values is observed in general with an increase in pKa values. The findings reveal that a stronger Broensted acid in most cases behaves as a stronger Lewis acid as well. However it is not necessarily true for all acids.
|
ဘရုန်စတက်နှင့် လော်ရီ အက်ဆစ်-အခြေသီအိုရီသည် ပရိုတွန်ပေးအပ်ခြင်း သို့မဟုတ် လက်ခံခြင်းစွမ်းရည် ( solvent ရှိခြင်း သို့မဟုတ် မရှိခြင်းအခြေအနေများတွင်) ကို အခြေခံသည်။ လျူးဝစ် အက်ဆစ်-အခြေသီအိုရီမှာမူ အီလက်ထရွန်အတွဲ လက်ခံခြင်း သို့မဟုတ် ပေးအပ်ခြင်း၏ စွဲလမ်းမှုကို အခြေခံသည်။ ဤသီအိုရီနှစ်ခုသည် တစ်ခုနှင့်တစ်ခု ကိုက်ညီမှုရှိမရှိကို DFT တွက်ချက်မှုဖြင့် စူးစမ်းလေ့လာပါမည်။ ဘရုန်စတက်နှင့် လော်ရီ အက်ဆစ်ဓာတ်အတွက် pKa ကို အညွှန်းကိန်းအဖြစ် အသုံးပြုပါသည်။ အော်ဂဲနစ်နှင့် အမ်အော်ဂဲနစ် အက်ဆစ် ၅၈ မျိုးအတွက် ionization potential၊ electron affinity၊ electronegativity၊ hardness နှင့် global electrophilicity ကဲ့သို့သော DFT အညွှန်းကိန်းများကို တွက်ချက်ထားသည်။ လျူးဝစ်အက်ဆစ်ဓာတ်အတွက် ဖြစ်နိုင်ခြေရှိသော အညွှန်းကိန်းများအဖြစ် trimethyl amine (အားကောင်းသော အခြေ) နှင့် ဤအက်ဆစ်များ၏ တုံ့ပြန်မှုအတွက် အပိုင်းအစ အီလက်ထရွန် လွှဲပြောင်းမှု del(N) နှင့် ဆက်စပ်စွဲအင်အား del(E) တို့ကို အသုံးပြုသည်။ pKa တန်ဖိုးများ တိုးလာသည်နှင့်အမျှ del(N) နှင့် (-del(E)) တန်ဖိုးများတွင် ချို့ယွင်းသော ထိုးမြှောက်ကျဆင်းမှုကို ယေဘုယျအားဖြင့် တွေ့ရှိရသည်။ ရလဒ်များအရ ပို၍အားကောင်းသော ဘရုန်စတက် အက်ဆစ်သည် အများအားဖြင့် ပို၍အားကောင်းသော လျူးဝစ်အက်ဆစ်အဖြစ်လည်း ပြုမူလေ့ရှိသည်။ သို့ရာတွင် အက်ဆစ်အားလုံးအတွက် မှန်ကန်ခြင်း မရှိပါ။
|
my
|
To interact seamlessly with robots, users must infer the causes of a robot's behavior and be confident about that inference. Hence, trust is a necessary condition for human-robot collaboration (HRC). Despite its crucial role, it is largely unknown how trust emerges, develops, and supports human interactions with nonhuman artefacts. Here, we review the literature on trust, human-robot interaction, human-robot collaboration, and human interaction at large. Early models of trust suggest that trust entails a trade-off between benevolence and competence, while studies of human-to-human interaction emphasize the role of shared behavior and mutual knowledge in the gradual building of trust. We then introduce a model of trust as an agent's best explanation for reliable sensory exchange with an extended motor plant or partner. This model is based on the cognitive neuroscience of active inference and suggests that, in the context of HRC, trust can be cast in terms of virtual control over an artificial agent. In this setting, interactive feedback becomes a necessary component of the trustor's perception-action cycle. The resulting model has important implications for understanding human-robot interaction and collaboration, as it allows the traditional determinants of human trust to be defined in terms of active inference, information exchange and empowerment. Furthermore, this model suggests that boredom and surprise may be used as markers for under and over-reliance on the system. Finally, we examine the role of shared behavior in the genesis of trust, especially in the context of dyadic collaboration, suggesting important consequences for the acceptability and design of human-robot collaborative systems.
|
روبوٹس کے ساتھ بے دریغ تعامل کے لیے، صارفین کو روبوٹ کے رویے کی وجوہات کا اندازہ لگانا چاہیے اور اس اندازے کے بارے میں یقین رکھنا چاہیے۔ لہٰذا، انسان اور روبوٹ کے تعاون (ایچ آر سی) کے لیے اعتماد ایک ضروری شرط ہے۔ اس کے اہم کردار کے باوجود، یہ زیادہ تر نامعلوم ہے کہ اعتماد کیسے وجود میں آتا ہے، کیسے ترقی کرتا ہے، اور انسانی تعامل کو غیر انسانی آرٹیفیکٹس کے ساتھ کیسے معاونت فراہم کرتا ہے۔ یہاں ہم اعتماد، انسان اور روبوٹ کے تعامل، انسان اور روبوٹ کے تعاون، اور عمومی طور پر انسانی تعامل پر لکھی گئی ادب کا جائزہ لیتے ہیں۔ اعتماد کے ابتدائی ماڈلز بتاتے ہیں کہ اعتماد میں نیک نیتی اور اہلیت کے درمیان ایک سودے بازی شامل ہوتی ہے، جبکہ انسان سے انسان کے تعامل کے مطالعات اعتماد کی تدریجی تعمیر میں مشترکہ رویے اور باہمی علم کے کردار پر زور دیتے ہیں۔ پھر ہم اعتماد کا ایک ماڈل پیش کرتے ہیں جس میں اعتماد کسی ایجنٹ کے لیے توسیع یافتہ موٹر پلانٹ یا شریک کے ساتھ قابل اعتماد حسی تبادلے کی بہترین وضاحت کے طور پر بیان کیا گیا ہے۔ یہ ماڈل ایکٹو انفرینس کے شعوری اعصابی سائنس پر مبنی ہے اور اس کا مشورہ ہے کہ ایچ آر سی کے تناظر میں، اعتماد کو مصنوعی ایجنٹ پر ورچوئل کنٹرول کے اصطلاحات میں پیش کیا جا سکتا ہے۔ اس سیٹنگ میں، تعاملی فیڈ بیک اعتماد کرنے والے کے ادراک اور عمل کے چکر کا ایک ضروری جزو بن جاتا ہے۔ نتیجے میں حاصل ہونے والے ماڈل کے انسانی روبوٹ تعامل اور تعاون کی تفہیم کے لیے اہم اثرات ہیں، کیونکہ یہ روایتی انسانی اعتماد کے عوامل کو ایکٹو انفرینس، معلومات کے تبادلے اور اختیار دینے کے اصطلاحات میں تعریف کرنے کی اجازت دیتا ہے۔ مزید برآں، یہ ماڈل یہ تجویز کرتا ہے کہ بوریت اور حیرت کو نظام پر کم یا زیادہ انحصار کے نشان کے طور پر استعمال کیا جا سکتا ہے۔ آخر میں، ہم اعتماد کی ابتدا میں مشترکہ رویے کے کردار کا جائزہ لیتے ہیں، خاص طور پر جوڑی وار تعاون کے تناظر میں، جو انسانی روبوٹ تعاونی نظاموں کی قبولیت اور ڈیزائن کے لیے اہم نتائج کی تجویز کرتا ہے۔
|
ur
|
We propose a new Dark Energy parametrization based on the dynamics of a scalar field. We use an equation of state $w=(x-1)/(x+1)$, with $x=E_k/V$, the ratio of kinetic energy $E_k=\dot\phi^2/2$ and potential $V$. The eq. of motion gives $x=(L/6)(V/3H^2)$ and with a solution $x=([1+2 L/3(1+y)]^{1/2}-1)(1+y)/2$ where $y\equiv \rm/V$ and $L\equiv (V'/V)^2 (1+q)^2,\, q\equiv\ddot\p/V'$. Since the universe is accelerating at present time we use the slow roll approximation in which case we have $|q|\ll 1$ and $L\simeq (V'/V)^2$. However, the derivation of $L$ is exact and has no approximation. By choosing an appropriate ansatz for $L$ we obtain a wide class of behavior for the evolution of Dark Energy without the need to specify the potential $V$. In fact $w$ can either grow and later decrease, or other way around, as a function of redshift and it is constraint between $-1\leq w\leq 1$ as for any canonical scalar field with only gravitational interaction. Furthermore, we also calculate the perturbations of DE and since the evolution of DE is motivated by the dynamics of a scalar field the homogenous and its perturbations can be used to determine the form of the potential and the nature of Dark Energy. Since our parametrization is on $L$ we can easily connect it with the scalar potential $V(\phi)$.
|
我们提出一种基于标量场动力学的新型暗能量参数化方法。我们采用状态方程 $w=(x-1)/(x+1)$，其中 $x=E_k/V$，$E_k=\dot\phi^2/2$ 为动能，$V$ 为势能。运动方程给出 $x=(L/6)(V/3H^2)$，其解为 $x=([1+2 L/3(1+y)]^{1/2}-1)(1+y)/2$，其中 $y\equiv \dot V/V$，$L\equiv (V'/V)^2 (1+q)^2$，$q\equiv\ddot\phi/V'$。由于当前宇宙处于加速膨胀状态，我们采用缓变近似，在此情况下有 $|q|\ll 1$，且 $L\simeq (V'/V)^2$。然而，$L$ 的推导是精确的，不依赖任何近似。通过为 $L$ 选择适当的试探形式，我们可以在不预先指定势能 $V$ 的情况下，获得一大类暗能量演化行为。事实上，$w$ 随红移的变化可以先增大后减小，或相反，且其值始终满足 $-1\leq w\leq 1$，这与仅存在引力相互作用的正则标量场一致。此外，我们还计算了暗能量的扰动，由于暗能量的演化源于标量场的动力学，因此其均匀部分及其扰动可用于确定势能的形式以及暗能量的本质。由于我们的参数化基于 $L$，因此可以方便地将其与标量势 $V(\phi)$ 联系起来。
|
zh
|
We present a study of analytic models of starless cores whose line profiles have ``infall asymmetry,'' or blue-skewed shapes indicative of contracting motions. We compare the ability of two types of analytical radiative transfer models to reproduce the line profiles and infall speeds of centrally condensed starless cores whose infall speeds are spatially constant and range between 0 and 0.2 km s-1. The model line profiles of HCO+ (J=1-0) and HCO+ (J=3-2) are produced by a self-consistent Monte Carlo radiative transfer code. The analytic models assume that the excitation temperature in the front of the cloud is either constant (``two-layer'' model) or increases inward as a linear function of optical depth (``hill'' model). Each analytic model is matched to the line profile by rapid least-squares fitting. The blue-asymmetric line profiles with two peaks, or with a blue shifted peak and a red shifted shoulder, can be well fit by the ``HILL5'' model (a five parameter version of the hill model), with an RMS error of 0.02 km s-1. A peak signal to noise ratio of at least 30 in the molecular line observations is required for performing these analytic radiative transfer fits to the line profiles.
|
Presentamos un estudio de modelos analíticos de núcleos sin estrellas cuyos perfiles de línea presentan «asimetría por acreción», o formas inclinadas hacia el azul indicativas de movimientos de contracción. Comparamos la capacidad de dos tipos de modelos analíticos de transferencia radiativa para reproducir los perfiles de línea y las velocidades de acreción de núcleos sin estrellas con densidad central cuya velocidad de acreción es espacialmente constante y varía entre 0 y 0.2 km s⁻¹. Los perfiles de línea modelo de HCO⁺ (J=1-0) y HCO⁺ (J=3-2) son generados mediante un código autoconsistente de transferencia radiativa Monte Carlo. Los modelos analíticos asumen que la temperatura de excitación en la parte frontal de la nube es constante (modelo de «dos capas») o aumenta hacia el interior como una función lineal de la profundidad óptica (modelo de «colina»). Cada modelo analítico se ajusta al perfil de línea mediante un ajuste rápido por mínimos cuadrados. Los perfiles de línea asimétricos hacia el azul con dos picos, o con un pico desplazado al azul y un hombro desplazado al rojo, pueden ajustarse adecuadamente mediante el modelo «HILL5» (una versión del modelo de colina con cinco parámetros), con un error RMS de 0.02 km s⁻¹. Se requiere una relación señal-ruido pico de al menos 30 en las observaciones de líneas moleculares para realizar estos ajustes analíticos de transferencia radiativa a los perfiles de línea.
|
es
|
A simple one-dimensional model for SNS weak links in the ballistic limit is presented. In the presence of a bias voltage, the quasiparticle state at any given instant of time is described as a superposition of that particular set of phase-dependent Andreev bound states that belongs to the specific phase difference present at this instant between the superconducting banks. The treatment -- basically a form of adiabatic perturbation theory -- has a strong formal similarity to the treatment of the k-space dynamics of an electron in a periodic potential under perturbation by an external electric field, sufficiently strong to cause transitions across the energy gaps between bands (Zener tunneling). It is shown that the quasiparticle wave function retains its phase information during analogous transitions between Andreev bands. The experimental observation of Shapiro steps at one-half the canonical voltage follows naturally from the model, along with some of the experimental properties of these steps, especially their much weaker temperature dependence, compared to the canonical steps.
|
បានណែនាំម៉ូដែលមួយវិមាត្រសាមញ្ញសម្រាប់តំណភ្ជាប់ខ្សោយ SNS ក្នុងដែនកំណត់បាលីស្ទិក។ ក្នុងករណីមានវ៉ុលធាតុបន្ថែម ស្ថានភាព quasiparticle នៅពេលណាមួយត្រូវបានពិពណ៌នាថាជាផលបូករបស់សំណុំជាក់លាក់មួយនៃស្ថានភាព Andreev ដែលពឹងផ្អែកលើដំណាក់កាល ដែលស្ថិតនៅក្នុងភាពខុសគ្នានៃដំណាក់កាលជាក់លាក់មួយរវាងធនាគារអ៊ីសូអេឡិចត្រិច។ ការព្យាបាលនេះ ដែលជាទម្រង់មួយនៃទ្រឹស្តីរំខានអាដៀប៉ាទិច មានសារៈស្រដៀងគ្នាផ្នែកទម្រង់យ៉ាងខ្លាំងទៅនឹងការព្យាបាលនៃដំណើរការ k-space របស់អេឡិចត្រុងមួយនៅក្នុងសក្តានុពលខួប ដោយរំខានពីវាលអគ្គិសនីខាងក្រៅ ខ្លាំងគ្រប់គ្រាន់ដើម្បីបង្កើតការផ្លាស់ប្តូរឆ្លងកាត់គ្រាប់ថាមពលរវាងខ្សែបណ្តាញ (Zener tunneling)។ បានបង្ហាញថា អនុគមន៍រលក quasiparticle រក្សាសារប្រាកដនៃដំណាក់កាលរបស់វាក្នុងអំឡុងពេលការផ្លាស់ប្តូរស្រដៀងគ្នារវាងខ្សែបណ្តាញ Andreev។ ការសង្កេតពិសោធន៍លើជំហាន Shapiro នៅពាក់កណ្តាលវ៉ុលស្តង់ដារ កើតឡើងដោយធម្មជាតិពីម៉ូដែល រួមទាំងលក្ខណៈពិសោធន៍ខ្លះរបស់ជំហានទាំងនេះ ជាពិសេសការអាស្រ័យសីតុណ្ហភាពរបស់វាខ្សោយជាងច្រើន បើធៀបនឹងជំហានស្តង់ដារ។
|
km
|
Let G be a reductive algebraic group and H a closed subgroup of G. An affine embedding of the homogeneous space G/H is an affine G-variety with an open G-orbit isomorphic to G/H. We start with some basic properties of affine embeddings and consider the cases, where the theory is well-developed: toric varieties, normal SL(2)-embeddings, S-varieties, and algebraic monoids. We discuss connections between the theory of affine embeddings and Hilbert's 14th Problem via a theorem of Grosshans. We characterize affine homogeneous spaces G/H such that any affine embedding of G/H contains a finite number of G-orbits. The maximal value of modality over all affine embeddings of a given affine homogeneous space is computed and the group of equivariant automorphisms of an embedding is studied. As applications of the theory, we describe invariant algebras on homogeneous spaces of a compact Lie group and G-algebras with finitely generated invariant subalgebras.
|
អោយ G ជាក្រុមពីជគណិតបន្ថយ និង H ជាក្រុមរងបិទនៃ G។ ការដាក់បញ្ចូលលក្ខណៈអាហ្វិននៃលំហស្មើគ្នា G/H គឺជាប្រភេទអាហ្វិន G ដែលមាន G-វិសាលភាពបើកដែលស្មើគ្នាទៅនឹង G/H។ យើងចាប់ផ្តើមជាមួយនឹងលក្ខណៈមូលដ្ឋានខ្លះនៃការដាក់បញ្ចូលលក្ខណៈអាហ្វិន ហើយពិចារណាករណី ដែលទ្រឹស្តីនេះត្រូវបានអភិវឌ្ឍយ៉ាងល្អ៖ ប្រភេទត័រីក៍ ប្រភេទ SL(2) ដែលមានលក្ខណៈធម្មតា ប្រភេទ S និងម៉ូណូអ៊ីដពីជគណិត។ យើងពិភាក្សាអំពីទំនាក់ទំនងរវាងទ្រឹស្តីនៃការដាក់បញ្ចូលលក្ខណៈអាហ្វិន និងបញ្ហាទី 14 របស់ហីលប៊ែរត៍ តាមរយៈទ្រឹស្តីបទរបស់ក្រោសហ៍។ យើងធ្វើលក្ខណៈសម្គាល់នូវលំហស្មើគ្នាអាហ្វិន G/H ដែលមានលក្ខណៈថា ការដាក់បញ្ចូលអាហ្វិនណាមួយនៃ G/H មានចំនួនកំណត់នៃ G-វិសាលភាព។ តម្លៃអតិបរមានៃលក្ខណៈម៉ូដាល់លើការដាក់បញ្ចូលអាហ្វិនទាំងអស់នៃលំហស្មើគ្នាអាហ្វិនដែលបានផ្តល់ឱ្យមួយត្រូវបានគណនា ហើយក្រុមនៃស្វ័យប្រវត្តិដែលមានលក្ខណៈសមមូលនៃការដាក់បញ្ចូលមួយត្រូវបានសិក្សា។ ក្នុងនាមជាកម្មវិធីនៃទ្រឹស្តី យើងពិពណ៌នាអំពីពីជគណិតអវកាសលើលំហស្មើគ្នារបស់ក្រុមលីដែលមានសមាជិកកំណត់ និងពីជគណិត G ដែលមានពីជគណិតអវកាសកំណត់។
|
km
|
The purpose of a program analysis is to compute an abstract meaning for a program which approximates its dynamic behaviour. A compositional program analysis accomplishes this task with a divide-and-conquer strategy: the meaning of a program is computed by dividing it into sub-programs, computing their meaning, and then combining the results. Compositional program analyses are desirable because they can yield scalable (and easily parallelizable) program analyses. This paper presents algebraic framework for designing, implementing, and proving the correctness of compositional program analyses. A program analysis in our framework defined by an algebraic structure equipped with sequencing, choice, and iteration operations. From the analysis design perspective, a particularly interesting consequence of this is that the meaning of a loop is computed by applying the iteration operator to the loop body. This style of compositional loop analysis can yield interesting ways of computing loop invariants that cannot be defined iteratively. We identify a class of algorithms, the so-called path-expression algorithms [Tarjan1981,Scholz2007], which can be used to efficiently implement analyses in our framework. Lastly, we develop a theory for proving the correctness of an analysis by establishing an approximation relationship between an algebra defining a concrete semantics and an algebra defining an analysis.
|
プログラム解析の目的は、プログラムの動的振る舞いを近似するような抽象的な意味を計算することである。構成的プログラム解析は、分割統治戦略によってこの課題を達成する。すなわち、プログラムを部分プログラムに分割し、それぞれの意味を計算してから、その結果を統合することで、プログラム全体の意味を算出する。構成的プログラム解析は、スケーラブル（かつ容易に並列化可能）なプログラム解析を提供できるため望ましい。
本論文は、構成的プログラム解析の設計、実装、およびその正当性証明を行うための代数的枠組みを提示する。本枠組みにおけるプログラム解析は、順次、選択、反復の各演算を備えた代数構造によって定義される。解析設計の観点から特に興味深い帰結の一つは、ループの意味が、ループ本体に反復演算子を適用することで計算される点である。このような構成的なループ解析のスタイルは、反復的に定義できないループ不変条件を計算する新たな手法をもたらす可能性がある。
さらに、本枠組みにおける解析を効率的に実装するために利用可能なアルゴリズムのクラス、いわゆるパス表現アルゴリズム [Tarjan1981, Scholz2007] を特定する。最後に、具体的な意味論を定義する代数と解析を定義する代数との間の近似関係を確立することで、解析の正当性を証明する理論を展開する。
|
ja
|
Quantum information theory and strongly correlated electron systems share a common theme of macroscopic quantum entanglement. In both topological error correction codes and theories of quantum materials (spin liquid, heavy fermion and high-$T_c$ systems) entanglement is implemented by means of an emergent gauge symmetry. Inspired by these connections, we introduce a simple model for fermions moving in the deconfined phase of a $\mathbb Z_2$ gauge theory, by coupling Kitaev's toric code to mobile fermions. This permits us to exactly solve the ground state of this system and map out its phase diagram. Reversing the sign of the plaquette term in the toric code, permits us to tune the groundstate between an orthogonal metal and an orthogonal semimetal, in which gapless quasiparticles survive despite a gap in the spectrum of original fermions. The small-to-large Fermi surface transition between these two states occurs in a stepwise fashion with multiple intermediate phases. By using a novel diagrammatic technique we are able to explore physics beyond the integrable point, to examine various instabilities of the deconfined phase and to derive the critical theory at the transition between deconfined and confined phases. We outline how the fermionic toric code can be implemented as a quantum circuit thus providing an important link between quantum materials and quantum information theory.
|
Lý thuyết thông tin lượng tử và các hệ electron tương quan mạnh có chung một chủ đề là sự rối lượng tử vĩ mô. Trong cả các mã sửa lỗi tôpô và các lý thuyết về vật liệu lượng tử (chất lỏng spin, fermion nặng và các hệ nhiệt độ siêu dẫn cao $T_c$), sự rối được thực hiện thông qua một đối xứng gauge nổi trội. Lấy cảm hứng từ những liên hệ này, chúng tôi giới thiệu một mô hình đơn giản cho các fermion chuyển động trong pha không bị giam giữ của một lý thuyết gauge $\mathbb Z_2$, bằng cách ghép mã toric của Kitaev với các fermion di động. Điều này cho phép chúng tôi giải chính xác trạng thái cơ bản của hệ và vẽ được biểu đồ pha của nó. Việc đảo dấu số hạng liên kết ô vuông trong mã toric cho phép điều chỉnh trạng thái cơ bản giữa một kim loại trực giao và một bán kim loại trực giao, trong đó các hạt lượng tử không có khe vẫn tồn tại mặc dù phổ của các fermion ban đầu có khe. Chuyển tiếp từ bề mặt Fermi nhỏ sang lớn giữa hai trạng thái này xảy ra từng bước với nhiều pha trung gian. Bằng cách sử dụng một kỹ thuật biểu đồ mới, chúng tôi có thể khảo sát vật lý vượt quá điểm tích phân được, kiểm tra các bất ổn khác nhau của pha không bị giam giữ và suy ra lý thuyết tới hạn tại chuyển tiếp giữa pha không bị giam giữ và pha bị giam giữ. Chúng tôi phác thảo cách thực hiện mã toric fermion như một mạch lượng tử, từ đó tạo ra một liên kết quan trọng giữa vật liệu lượng tử và lý thuyết thông tin lượng tử.
|
vi
|
This paper analyzes how candidate choice prediction improves by different psychological predictors. To investigate this question, it collected an original survey dataset featuring the popular TV series "Game of Thrones". The respondents answered which character they anticipated to win in the final episode of the series, and explained their choice of the final candidate in free text from which sentiments were extracted. These sentiments were compared to feature sets derived from candidate likeability and candidate personality ratings. In our benchmarking of 10-fold cross-validation in 100 repetitions, all feature sets except the likeability ratings yielded a 10-11% improvement in accuracy on the holdout set over the base model. Treating the class imbalance with synthetic minority oversampling (SMOTE) increased holdout set performance by 20-34% but surprisingly not testing set performance. Taken together, our study provides a quantified estimation of the additional predictive value of psychological predictors. Likeability ratings were clearly outperformed by the feature sets based on personality, emotional valence, and basic emotions.
|
Questo articolo analizza in che modo la previsione della scelta del candidato migliora grazie a diversi predittori psicologici. Per indagare questa domanda, è stato raccolto un dataset originale basato su un'indagine che riguarda la popolare serie televisiva "Game of Thrones". I partecipanti hanno indicato quale personaggio ritenevano avrebbe vinto nell'episodio finale della serie e hanno spiegato la propria scelta del candidato finale attraverso testi liberi, dai quali sono stati estratti i sentimenti. Questi sentimenti sono stati confrontati con insiemi di caratteristiche derivati dalle valutazioni di gradimento del candidato e dalle valutazioni della personalità del candidato. Nella nostra valutazione comparativa basata su una validazione incrociata 10-fold ripetuta 100 volte, tutti gli insiemi di caratteristiche, tranne le valutazioni di gradimento, hanno determinato un miglioramento dell'accuratezza del 10-11% rispetto al modello base sul set riservato. L'applicazione della tecnica SMOTE (sinteticamente aumentando il campione della classe minoritaria) ha aumentato le prestazioni sul set riservato del 20-34%, ma sorprendentemente non ha migliorato le prestazioni sul set di test. Nel complesso, il nostro studio fornisce una stima quantificata del valore predittivo aggiuntivo offerto dai predittori psicologici. Le valutazioni di gradimento sono state chiaramente superate dagli insiemi di caratteristiche basati sulla personalità, sulla valenza emotiva e sulle emozioni di base.
|
it
|
Let $k,n,m \in \mathbb{Z}^+$ integers such that $k\leq n \leq m$, let $\mathrm{G}_{n,k}\in \mathbb{F}_{q^m}^n$ be a Delsarte-Gabidulin code. Wachter-Zeh proven that codes belonging to this family cannot be efficiently list decoded for any radius $\tau$, providing $\tau$ is large enough. This achievement essentially relies on proving a lower bound for the list size of some specific words in $\mathbb{F}_{q^m}^n \setminus \mathrm{G}_{n,k}$. In 2016, Raviv and Wachter-Zeh improved this bound in a special case, i.e. when $n\mid m$. As a consequence, they were able to detect infinite families of Delsarte-Gabidulin codes that cannot be efficiently list decoded at all. In this article we determine similar lower bounds for Maximum Rank Distance codes belonging to a wider class of examples, containing Generalized Gabidulin codes, Generalized Twisted Gabidulin codes, and examples recently described by the first author and Yue Zhou. By exploiting arguments suchlike those used in the above mentioned papers, when $n\mid m$, we also show infinite families of generalized Gabidulin codes that cannot be list decoded efficiently at any radius greater than or equal to $\left\lfloor \frac{d-1}2 \right\rfloor+1$, where $d$ is its minimum distance. Nonetheless, in all other examples belonging to above mentioned class, we detect infinite families that cannot be list decoded efficiently at any radius greater than or equal to $\left\lfloor \frac{d-1}2 \right\rfloor+2$, where $d$ is its minimum distance. Finally, relying on the properties of a set of subspace trinomials recently presented by McGuire and Mueller, we are able to prove that any rank metric code of $\mathbb{F}_{q^m}^n$ of order $q^{kn}$ with $n$ dividing $m$, such that $4n-3$ is a square in $\mathbb{Z}$ and containing $\mathrm{G}_{n,2}$, is not efficiently list decodable at some values of the radius $\tau$.
|
$k,n,m \in \mathbb{Z}^+$ бүтін сандары $k\leq n \leq m$ теңсіздігін қанағаттандырсын, $\mathrm{G}_{n,k}\in \mathbb{F}_{q^m}^n$ — Делсарт-Габидулин коды болсын. Вахтер-Цех бұл тұқымдағы кодтарды $\tau$ жеткілікті үлкен болған жағдайда кез-келген $\tau$ радиусы үшін тиімді түрде тізімдік декодтауға болмайтынын дәлелдеді. Бұл нәтижеге $\mathbb{F}_{q^m}^n \setminus \mathrm{G}_{n,k}$ жиынындағы кейбір нақты сөздердің тізім өлшемі үшін төменгі бағаны дәлелдеу арқылы қол жеткізілді. 2016 жылы Равив пен Вахтер-Цех бұл бағаны $n\mid m$ болатын дербес жағдайда жақсартты. Нәтижесінде олар тиімді түрде мүлдем тізімдік декодтауға болмайтын Делсарт-Габидулин кодтарының шексіз тұқымдарын анықтай алды. Бұл мақалада біз Жалпыланған Габидулин кодтарын, Жалпыланған Бұралған Габидулин кодтарын және мақаланың бірінші авторы мен Юе Чжоу тарапынан жақында сипатталған мысалдарды қамтитын кеңірек мысалдар класына тиісті Максималды Ранг Арақашықтық кодтары үшін ұқсас төменгі бағаларды анықтаймыз. Жоғарыда аталған мақалаларда қолданылған пайымдауларды пайдалана отырып, $n\mid m$ болған кезде $d$ — оның ең кіші қашықтығы болатын $\left\lfloor \frac{d-1}2 \right\rfloor+1$-ден үлкен немесе тең кез-келген радиус үшін тиімді түрде тізімдік декодтауға болмайтын жалпыланған Габидулин кодтарының шексіз тұқымдары бар екенін көрсетеміз. Дегенмен, жоғарыда аталған класқа тиісті басқа барлық мысалдарда $d$ — оның ең кіші қашықтығы болатын $\left\lfloor \frac{d-1}2 \right\rfloor+2$-ден үлкен немесе тең кез-келген радиус үшін тиімді түрде тізімдік декодтауға болмайтын шексіз тұқымдарды анықтаймыз. Соңында, МакГуайр мен Мюллер тарапынан жақында ұсынылған кеңістіктік үшмүшеліктер жиынының қасиеттеріне сүйене отырып, $n$ саны $m$-ді бөлетін, $4n-3$ саны $\mathbb{Z}$-де толық квадрат болатын және $\mathrm{G}_{n,2}$-ні қамтитын $\mathbb{F}_{q^m}^n$-нің реті $q^{kn}$ болатын кез-келген ранг метрикалық коды кейбір $\tau$ радиусының мәндерінде тиімді түрде тізімдік декодтауға болмайтынын дәлелдейміз.
|
kk
|
Following Riley's work, for each 2-bridge link $K(r)$ of slope $r\in\QQ$ and an integer or a half-integer $n$ greater than 1, we introduce the {\it Heckoid orbifold $\orbs(r;n)$} and the {\it Heckoid group $\Hecke(r;n)=\pi_1(\orbs(r;n))$ of index $n$ for $K(r)$}. When $n$ is an integer, $\orbs(r;n)$ is called an {\it even} Heckoid orbifold; in this case, the underlying space is the exterior of $K(r)$, and the singular set is the lower tunnel of $K(r)$ with index $n$. The main purpose of this note is to announce answers to the following questions for even Heckoid orbifolds. (1) For an essential simple loop on a 4-punctured sphere $\PConway$ in $\orbs(r;n)$ determined by the 2-bridge sphere of $K(r)$, when is it null-homotopic in $\orbs(r;n)$? (2) For two distinct essential simple loops on $\PConway$, when are they homotopic in $\orbs(r;n)$? We also announce applications of these results to character varieties, McShane's identity, and epimorphisms from 2-bridge link groups onto Heckoid groups.
|
릴리의 연구에 이어, 기울기 $ r\in\QQ $를 갖는 각각의 2-교차 결합 $ K(r) $ 및 1보다 큰 정수 또는 반정수 $ n $에 대해, 우리는 $ K(r) $에 대한 지표 $ n $의 {\it 헤크오이드 오브폴드 $\orbs(r;n)$}와 {\it 헤크오이드 군 $\Hecke(r;n)=\pi_1(\orbs(r;n))$}를 도입한다. $ n $이 정수일 때, $\orbs(r;n)$은 {\it 짝수} 헤크오이드 오브폴드라 불린다. 이 경우, 그 기본 공간은 $ K(r) $의 외부이고, 특이집합은 지표가 $ n $인 $ K(r) $의 하부 터널이다. 이 논문의 주요 목적은 짝수 헤크오이드 오브폴드에 대한 다음 질문들에 대한 답을 제시하는 것이다. (1) $ K(r) $의 2-교차 구면에 의해 결정되는 $\orbs(r;n)$의 4점 제거 구면 $\PConway$ 위에 있는 본질적인 단순 고리가 $\orbs(r;n)$ 안에서 언제 호모토피적으로 자명한가? (2) $\PConway$ 위의 두 개의 서로 다른 본질적인 단순 고리가 $\orbs(r;n)$ 안에서 언제 호모토픽한가? 또한 우리는 이러한 결과들이 캐릭터 다양체, 맥셰인의 항등식, 그리고 2-교차 결합 군에서 헤크오이드 군으로의 전사준동형에 응용되는 것들에 대해서도 제시한다.
|
ko
|
An equichordal tight fusion frame (ECTFF) is a finite sequence of equi-dimensional subspaces of a finite-dimensional Hilbert space that achieves equality in Conway, Hardin and Sloane's simplex bound. Every ECTFF is a type of optimal Grassmannian code, being a way to arrange a given number of members of a Grassmannian so that the minimal chordal distance between any pair of them is as large as possible. Any nontrivial ECTFF has both a Naimark complement and spatial complement which themselves are ECTFFs. It turns out that whenever the number of subspaces is at least five, taking iterated alternating Naimark and spatial complements of one ECTFF yields an infinite family of them with distinct parameters. This makes it challenging to certify the novelty of any recently discovered ECTFF: how can one guarantee that it does not arise from any previously known construction in such a Naimark-spatial way? In this paper, we propose a solution to this problem, showing that any ECTFF is a member of a Naimark-spatial family originating from either a trivial ECTFF or one with unique "minimal" parameters. In the latter case, if its minimal parameters do not match those of any previously known ECTFF, it is certifiably new. As a proof of concept, we then use these ideas to certify the novelty of some ECTFFs arising from a new method for constructing them from difference families for finite abelian groups. This method properly generalizes King's construction of ECTFFs from semiregular divisible difference sets.
|
ایک مساوی وتری تنگ تال مُلائیہ (ایکٹی ایف ایف) متناہی البعد ہلبرٹ سپیس کے مساوی البعد ذیلی سپیس کا ایک متناہی تسلسل ہے جو کانوے، ہارڈن اور سلوان کی سادہ حد میں مساوات حاصل کرتا ہے۔ ہر ایک ایکٹی ایف ایف ایک مثالی گراس مینیئن کوڈ کی ایک قسم ہے، جو گراس مینیئن کے دیے گئے تعداد کے ارکان کو اس طرح ترتیب دینے کا ایک طریقہ ہے کہ ان میں سے کسی بھی جوڑی کے درمیان کم از کم وتری فاصلہ زیادہ سے زیادہ ہو۔ کوئی بھی غیر سادہ ایکٹی ایف ایف ایک نیمرک تکمیل اور جگہی تکمیل دونوں رکھتا ہے جو خود بخود ایکٹی ایف ایف ہوتی ہیں۔ یہ بات سامنے آئی ہے کہ جب تک ذیلی سپیس کی تعداد کم از کم پانچ ہو، ایک ایکٹی ایف ایف کی مسلسل متبادل نیمرک اور جگہی تکمیل لینے سے ان کی ایک لامحدود خاندان پیدا ہوتی ہے جس کے مختلف پیرامیٹرز ہوتے ہیں۔ اس سے کسی حالیہ دریافت شدہ ایکٹی ایف ایف کی تازگی کی تصدیق کرنا مشکل ہو جاتا ہے: کیسے یقین دلایا جا سکتا ہے کہ یہ کسی پہلے سے جانے جانے والے تعمیرات سے اس طرح کے نیمرک-جگہی طریقے سے حاصل نہیں ہوا؟ اس مقالے میں، ہم اس مسئلے کا ایک حل پیش کرتے ہیں، جس میں دکھایا گیا ہے کہ کوئی بھی ایکٹی ایف ایف ایک نیمرک-جگہی خاندان کا رکن ہوتا ہے جو یا تو ایک سادہ ایکٹی ایف ایف سے یا ایک ایسے ایکٹی ایف ایف سے نکلتا ہے جس کے منفرد "کم از کم" پیرامیٹرز ہوتے ہیں۔ اس آخری صورت میں، اگر اس کے کم از کم پیرامیٹرز کسی پہلے سے جانے جانے والے ایکٹی ایف ایف کے پیرامیٹرز سے مطابقت نہیں رکھتے، تو اس کی تازگی کی تصدیق کی جا سکتی ہے۔ تصور کی تصدیق کے طور پر، ہم پھر ان خیالات کو استعمال کرتے ہوئے بعض ایکٹی ایف ایف کی تازگی کی تصدیق کرتے ہیں جو متناہی ابیلی گروپس کے لیے فرق خاندانوں سے انہیں تعمیر کرنے کے ایک نئے طریقہ سے پیدا ہوتے ہیں۔ یہ طریقہ کنگ کی نیم منظم تقسیم پذیر فرق سیٹس سے ایکٹی ایف ایف کی تعمیر کے طریقہ کی مناسب تعمیم ہے۔
|
ur
|
Neuromorphology is crucial to identifying neuronal subtypes and understanding learning. It is also implicated in neurological disease. However, standard morphological analysis focuses on macroscopic features such as branching frequency and connectivity between regions, and often neglects the internal geometry of neurons. In this work, we treat neuron trace points as a sampling of differentiable curves and fit them with a set of branching B-splines. We designed our representation with the Frenet-Serret formulas from differential geometry in mind. The Frenet-Serret formulas completely characterize smooth curves, and involve two parameters, curvature and torsion. Our representation makes it possible to compute these parameters from neuron traces in closed form. These parameters are defined continuously along the curve, in contrast to other parameters like tortuosity which depend on start and end points. We applied our method to a dataset of cortical projection neurons traced in two mouse brains, and found that the parameters are distributed differently between primary, collateral, and terminal axon branches, thus quantifying geometric differences between different components of an axonal arbor. The results agreed in both brains, further validating our representation. The code used in this work can be readily applied to neuron traces in SWC format and is available in our open-source Python package brainlit: http://brainlit.neurodata.io/.
|
신경형태학은 뉴런 아형을 식별하고 학습을 이해하는 데 중요하며, 신경계 질환에도 관련이 있다. 그러나 기존의 형태학적 분석은 가지치기 빈도나 영역 간 연결성과 같은 거시적 특징에 초점을 맞추고 뉴런의 내부 기하 구조를 종종 소홀히 한다. 본 연구에서는 뉴런 추적 점들을 미분 가능 곡선의 샘플링으로 간주하고, 일련의 가지친 B-스플라인으로 적합시켰다. 본 연구의 표현 방식은 미분기하학의 프레네-세레 공식(Frenet-Serret formulas)을 염두에 두고 설계되었다. 프레네-세레 공식은 곡선을 완전히 특징짓는 것으로, 곡률(curvature)과 비틀림(torsion)이라는 두 가지 매개변수를 포함한다. 본 연구의 표현 방식을 통해 뉴런 추적 데이터로부터 이러한 매개변수를 닫힌 형태(closed form)로 계산할 수 있게 되었다. 이러한 매개변수들은 지그재그 정도(tortuosity)처럼 시작점과 끝점에 의존하는 다른 매개변수들과 달리 곡선을 따라 연속적으로 정의된다. 본 방법을 두 마리의 마우스 뇌에서 추적된 대뇌피질 투사 뉴런 데이터셋에 적용한 결과, 주축삭, 측지축삭, 말단축삭 가지 사이에서 매개변수의 분포가 다르게 나타나 축삭 수상돌기의 서로 다른 구성 요소 간 기하학적 차이를 정량화할 수 있었다. 두 뇌 모두에서 결과가 일치하여 본 표현 방식의 타당성이 추가로 입증되었다. 본 연구에서 사용된 코드는 SWC 형식의 뉴런 추적 데이터에 즉시 적용 가능하며, 오픈소스 파이썬 패키지 brainlit을 통해 이용할 수 있다: http://brainlit.neurodata.io/.
|
ko
|
In this work, we propose to utilize discrete graph Ricci flow to alter network entropy through feedback control. Given such feedback input can reverse entropic changes, we adapt the moniker of Maxwells Demon to motivate our approach. In particular, it has been recently shown that Ricci curvature from geometry is intrinsically connected to Boltzmann entropy as well as functional robustness of networks or the ability to maintain functionality in the presence of random fluctuations. From this, the discrete Ricci flow provides a natural avenue to rewire a particular networks underlying geometry to improve throughout and resilience. Due to the real-world setting for which one may be interested in imposing nonlinear constraints amongst particular agents to understand the network dynamic evolution, controlling discrete Ricci flow may be necessary (e.g., we may seek to understand the entropic dynamics and curvature flow between two networks as opposed to solely curvature shrinkage). In turn, this can be formulated as a natural control problem for which we employ feedback control towards discrete Ricci-based flow and show that under certain discretization, namely Ollivier-Ricci curvature, one can show stability via Lyapunov analysis. We conclude with preliminary results with remarks on potential applications that will be a subject of future work.
|
En este trabajo, proponemos utilizar el flujo de Ricci discreto en grafos para alterar la entropía de redes mediante control por retroalimentación. Dado que dicha entrada de retroalimentación puede revertir los cambios entrópicos, adoptamos el apelativo de el Demonio de Maxwell para motivar nuestro enfoque. En particular, recientemente se ha demostrado que la curvatura de Ricci proveniente de la geometría está intrínsecamente relacionada con la entropía de Boltzmann, así como con la robustez funcional de las redes o la capacidad de mantener la funcionalidad ante fluctuaciones aleatorias. A partir de esto, el flujo de Ricci discreto proporciona una vía natural para reconectar la geometría subyacente de una red particular con el fin de mejorar su rendimiento y resiliencia. Debido al contexto del mundo real en el que uno podría estar interesado en imponer restricciones no lineales entre agentes particulares para comprender la evolución dinámica de la red, puede ser necesario controlar el flujo de Ricci discreto (por ejemplo, podríamos buscar comprender la dinámica entrópica y el flujo de curvatura entre dos redes, en lugar de únicamente la contracción de la curvatura). A su vez, esto puede formularse como un problema de control natural para el cual empleamos control por retroalimentación dirigido al flujo basado en Ricci discreto, y mostramos que, bajo cierta discretización, específicamente la curvatura de Ollivier-Ricci, se puede demostrar estabilidad mediante análisis de Lyapunov. Concluimos con resultados preliminares y observaciones sobre posibles aplicaciones que serán objeto de trabajos futuros.
|
es
|
Motion planning is an essential component in most of today's robotic applications. In this work, we consider the learning setting, where a set of solved motion planning problems is used to improve the efficiency of motion planning on different, yet similar problems. This setting is important in applications with rapidly changing environments such as in e-commerce, among others. We investigate a general deep learning based approach, where a neural network is trained to map an image of the domain, the current robot state, and a goal robot state to the next robot state in the plan. We focus on the learning algorithm, and compare supervised learning methods with reinforcement learning (RL) algorithms. We first establish that supervised learning approaches are inferior in their accuracy due to insufficient data on the boundary of the obstacles, an issue that RL methods mitigate by actively exploring the domain. We then propose a modification of the popular DDPG RL algorithm that is tailored to motion planning domains, by exploiting the known model in the problem and the set of solved plans in the data. We show that our algorithm, dubbed DDPG-MP, significantly improves the accuracy of the learned motion planning policy. Finally, we show that given enough training data, our method can plan significantly faster on novel domains than off-the-shelf sampling based motion planners. Results of our experiments are shown in https://youtu.be/wHQ4Y4mBRb8.
|
Ang pagpaplano ng galaw ay isang mahalagang bahagi sa karamihan ng mga aplikasyon ng robot sa kasalukuyan. Sa gawaing ito, pinag-aaralan natin ang isang kalagayang pangkatuto, kung saan isang pangkat ng mga naresolbang problema sa pagpaplano ng galaw ang ginagamit upang mapataas ang kahusayan ng pagpaplano ng galaw sa iba't ibang ngunit magkakatulad na mga problema. Mahalaga ang ganitong kalagayan sa mga aplikasyon na may mabilis na pagbabagong kapaligiran tulad ng sa e-komersiyo, bukod sa iba pa. Sinusuri namin ang isang pangkalahatang pamamaraan batay sa malalim na pagkatuto (deep learning), kung saan isang neural network ang sinanay upang i-mapa ang isang larawan ng larangan, ang kasalukuyang kalagayan ng robot, at ang layuning kalagayan ng robot patungo sa susunod na kalagayan ng robot sa plano. Nakatuon kami sa algoritmo ng pagkatuto, at inihahambing ang mga pamamaraan ng supervised learning sa mga algorithm ng reinforcement learning (RL). Una naming itinatag na ang mga pamamaraan ng supervised learning ay mas mababa sa kanilang kawastuhan dahil sa hindi sapat na datos sa gilid ng mga hadlang, isang isyu na binabawasan ng mga pamamaraang RL sa pamamagitan ng aktibong paglalakbay sa loob ng larangan. Pagkatapos, iminumungkahi namin ang isang pagbabago sa sikat na DDPG RL algorithm na naaayon sa mga larangan ng pagpaplano ng galaw, sa pamamagitan ng paggamit ng kilalang modelo sa problema at ng pangkat ng mga naresolbang plano sa datos. Ipinapakita namin na ang aming algorithm, na tinaguriang DDPG-MP, ay malaki ang nagpapabuti sa kawastuhan ng natutunang patakaran sa pagpaplano ng galaw. Sa wakas, ipinapakita namin na sa sapat na datos sa pagsasanay, ang aming pamamaraan ay mas mabilis sa pagpaplano sa mga bagong larangan kumpara sa mga karaniwang sampling-based na mga planner ng galaw. Ang mga resulta ng aming mga eksperimento ay ipinapakita sa https://youtu.be/wHQ4Y4mBRb8.
|
tl
|
To shed more light on the nature of the observed Ly{\alpha} absorption during transits of HD 209458b and to quantify the major mechanisms responsible for the production of fast hydrogen atoms (the so called energetic neutral atoms, ENAs) around the planet, 2D hydrodynamic multifluid modeling of the expanding planetary upper atmosphere, which is driven by stellar XUV, and its interaction with the stellar wind has been performed. The model selfconsistently describes the escaping planetary wind, taking into account the generation of ENAs due to particle acceleration by the radiation pressure and by the charge exchange between the stellar wind protons and planetary atoms. The calculations in a wide range of stellar wind parameters and XUV flux values showed that under typical Sun-like star conditions, the amount of generated ENAs is too small, and the observed absorption at the level of 6-8 percent can be attributed only to the non-resonant natural line broadening. For lower XUV fluxes, e.g., during the activity minima, the number of planetary atoms that survive photoionization and give rise to ENAs increases, resulting in up to 10-15 percent absorption at the blue wing of the Lya line, caused by resonant thermal line broadening. A similar asymmetric absorption can be seen under the conditions realized during coronal mass ejections, when sufficiently high stellar wind pressure confines the escaping planetary material within a kind of bowshock around the planet. It was found that the radiation pressure in all considered cases has a negligible contribution to the production of ENAs and the corresponding absorption.
|
HD 209458b의 통과(transit) 동안 관측된 Lyα 흡수의 성질을 더 명확히 하고, 행성 주변에서 빠른 수소 원자(소위 고에너지 중성 원자, ENA) 생성의 주요 메커니즘을 정량화하기 위해, 항성의 XUV에 의해 유도되는 팽창하는 행성 고층 대기와 항성풍과의 상호작용에 대한 2차원 수중성 다중유체(hydrodynamic multifluid) 모델링을 수행하였다. 이 모델은 항성풍 양성자와 행성 원자 사이의 전하 교환 및 복사압에 의한 입자 가속으로 인한 ENA 생성을 고려하여, 탈출하는 행성풍을 자기일관적(self-consistently)으로 기술한다. 항성풍 파라미터와 XUV 플럭스 값의 넓은 범위에 걸친 계산 결과, 태양과 유사한 항성 조건에서는 생성된 ENA의 양이 너무 적어, 관측된 6-8% 수준의 흡수는 공명이 아닌 고유 스펙트럼선 확장(natural line broadening)에 기인하는 것으로 설명할 수 있었다. XUV 플럭스가 낮은 경우, 예를 들어 활동 최소기 동안에는 광이온화를 피하여 살아남는 행성 원자의 수가 증가하여, 공명 열적 스펙트럼선 확장(resonant thermal line broadening)으로 인해 Lyα 선의 파장이 짧은 쪽(청색 날개, blue wing)에서 최대 10-15%의 흡수가 발생할 수 있다. 유사한 비대칭 흡수는 코로날 질량방출(CME) 동안과 같이 충분히 높은 항성풍 압력이 행성에서 탈출하는 물질을 행성 주위의 일종의 충격파(bowshock) 내부로 제한하는 조건에서도 관측될 수 있다. 분석 결과, 고려된 모든 경우에서 복사압은 ENA 생성과 이에 상응하는 흡수에 거의 기여하지 않는 것으로 나타났다.
|
ko
|
The routing and wavelength assignment with protection is an important problem in telecommunications. Given an optical network and incoming connection requests, a commonly studied variant of the problem aims to grant maximum number of requests by assigning lightpaths at minimum network resource usage level, while ensuring the provided services remain functional in case of a single-link failure through dedicated path protection. We consider a practically relevant version where alternative lightpaths for requests are assumed to be given as a precomputed set, and show that it is NP-hard. We formulate the problem as an integer programming (IP) model, and also use it as a foundation to develop a novel quadratic unconstrained binary optimization (QUBO) model, which can be both directly solved by a state-of-the-art solver like GUROBI. We present necessary and sufficient conditions on objective function parameters to prioritize request granting objective over wavelength-link usage for both models, and a sufficient condition to ensure the exactness of the QUBO model. Moreover, we implement a problem-specific branch-and-cut algorithm for the IP model, and employ a new quantum-inspired technology, Digital Annealer (DA), for the QUBO model. We conduct computational experiments on a large suite of instances that are hard to optimally solve in order to assess the efficiency and efficacy of all of these approaches as well as a problem-specific heuristic. The results show that the emerging technology DA outperforms the considered established techniques coupled with GUROBI, in finding mostly significantly better or as good solutions in only two minutes compared to two hours of run time, whereas the problem-specific heuristic fails to be competitive.
|
Koruma ile birlikte yönlendirme ve dalga boyu ataması, telekomünikasyon alanında önemli bir problemdir. Optik bir ağ ve gelen bağlantı istekleri verildiğinde, bu problemin yaygın olarak incelenen bir varyantı, tek bir bağlantı arızası durumunda özel yol koruması aracılığıyla sağlanan hizmetlerin işlevsel kalmasını sağlarken, minimum ağ kaynak kullanımı düzeyinde ışık yolları atayarak mümkün olan en fazla sayıda isteği kabul etmeyi amaçlar. İstekler için alternatif ışık yollarının önceden hesaplanmış bir küme olarak verildiği pratikte önemli olan bir versiyonu ele alırız ve bu problemin NP-zor olduğunu gösteririz. Problemi tamsayılı programlama (IP) modeli olarak formüle ederiz ve bu modeli temel alarak, GUROBI gibi gelişmiş bir çözücü ile doğrudan çözülebilecek yeni bir karesel kısıtsız ikili optimizasyon (QUBO) modeli geliştiririz. Her iki model için de istek kabul edilme amacının dalga boyu-bağlantı kullanımı amacına göre öncelik kazanmasını sağlayan amaç fonksiyonu parametreleri üzerinde gerekli ve yeterli koşulları sunarız ve QUBO modelinin kesinliğini garanti eden yeterli bir koşul belirtiriz. Ayrıca, IP modeli için problem özel bir dal-kesme algoritması uygularız ve QUBO modeli için yeni bir kuantum-ilahtechnoloji olan Dijital Tavlama (DA) yöntemini kullanırız. Tüm bu yaklaşımların ve problem özel bir sezgiselin etkinliğini ve verimliliğini değerlendirmek amacıyla, optimal olarak çözmek zor olan büyük bir örnek kümesi üzerinde hesaplamalı deneyler gerçekleştiririz. Sonuçlar, ortaya çıkan teknoloji olan DA'nın, iki saatlik çalışma süresine kıyasla yalnızca iki dakikada çoğunlukla önemli ölçüde daha iyi ya da aynı düzeyde çözümler bulması bakımından GUROBI ile birleştirilen mevcut tekniklerden üstün olduğunu gösterirken, problem özel sezgisel yöntemin rekabetçi olamadığını ortaya koymaktadır.
|
tr
|
Usual analyses based on scans of the seesaw parameter-space can be biassed since they do not cover in a fair way the complete parameter-space. More precisely, we show that in the common "R-parametrization", many acceptable R-matrices, compatible with the perturbativity of Yukawa couplings, are normally disregarded from the beginning, which produces biasses in the results. We give a straightforward procedure to scan the space of complex R-matrices in a complete way, giving a very simple rule to incorporate the perturbativity requirement as a condition for the entries of the R-matrix, something not considered before. As a relevant application of this, we show that the extended believe that BR(mu --> e, gamma) in supersymmetric seesaw models depends strongly on the value of theta_13 is an "optical effect" produced by such biassed scans, and does not hold after a careful analytical and numerical study. When the complete scan is done, BR(mu --> e, gamma) gets very insensitive to theta_13. Moreover, the values of the branching ratio are typically larger than those quoted in the literature, due to the large number of acceptable points in the parameter-space which were not considered before. Including (unflavoured) leptogenesis does not introduce any further dependence on theta_13, although decreases the typical value of BR(mu --> e, gamma).
|
ပုံဆွဲမှုနယ်ပြင်၏ ပုံဆွဲမှုများအပေါ်အခြေခံသည့် ပုံမှန်ခွဲခြမ်းစိတ်ဖြာမှုများသည် ပုံမှန်အားဖြင့် ပုံဆွဲမှုနယ်ပြင်၏ လုံးဝကျော်လွန်သော နယ်ပြင်ကို တရားမျှတစွာ ဖြည့်ဆည်းပေးခြင်းမရှိသောကြောင့် ဘီယက်စ် (biassed) ဖြစ်နိုင်ပါသည်။ ပို၍တိကျစွာဆိုရသော် "R-ပြောင်းလဲမှုအမျိုးအစား" တွင် ယူကားဝါ ဆက်သွယ်မှုများ၏ ပုံမှန်ဖြစ်မှုနှင့် ကိုက်ညီသော R-matrix အများအပြားကို ပုံမှန်အားဖြင့် အစပိုင်းတွင် လျစ်လျူရှုလေ့ရှိပြီး ထိုသို့သော ဘီယက်စ်များက ရလဒ်များတွင် ဘီယက်စ်များကို ဖြစ်ပေါ်စေပါသည်။ R-matrix များ၏ ရှုပ်ထွေးသောနယ်ပြင်ကို လုံးဝပုံဆွဲရန် လွယ်ကူသော လုပ်ငန်းစဉ်တစ်ခုကို ကျွန်ုပ်တို့ပေးပို့ပါသည်။ R-matrix ၏ အဝင်အထွက်များအတွက် အခြေအနေအဖြစ် ပုံမှန်ဖြစ်မှုလိုအပ်ချက်ကို ထည့်သွင်းရန် အလွန်ရိုးရှင်းသော စည်းမျဉ်းတစ်ခုကို ပေးပို့ပါသည်။ ယခင်က ထည့်သွင်းစဉ်းစားခြင်းမရှိပါ။ ထို့ကြောင့် အရေးပါသော အသုံးချမှုအဖြစ် ကျွန်ုပ်တို့သည် စူပါစီမက္ကကြီးများရှိ seesaw မော်ဒယ်များတွင် BR(mu --> e, gamma) သည် theta_13 ၏တန်ဖိုးအပေါ် အလွန်မျှော်လင့်နေသည်ဟု တိုးချဲ့ယုံကြည်မှုသည် ထိုကဲ့သို့သော ဘီယက်စ်များဖြင့် ဖြစ်ပေါ်သော "အလင်းရောင်သက်ရောက်မှု" ဖြစ်ပြီး ဂျီအိုမဲတြိက်နှင့် ဂဏန်းသင်္ချာဆိုင်ရာ လေ့လာမှုများအပြီးတွင် မမှန်ကန်ကြောင်း ပြသပါသည်။ ပုံဆွဲမှုနယ်ပြင်ကို လုံးဝပြုလုပ်သောအခါ BR(mu --> e, gamma) သည် theta_13 အပေါ် အလွန်အားနည်းစွာသာ တုံ့ပြန်ပါသည်။ ထို့အပြင် ပုံဆွဲမှုနယ်ပြင်တွင် ယခင်က ထည့်သွင်းစဉ်းစားခြင်းမရှိသော လက်ခံနိုင်သည့် အမှတ်များ၏ အရေအတွက်များပြားမှုကြောင့် ကွဲပြားမှု၏ တန်ဖိုးများသည် စာပေများတွင် ဖော်ပြထားသည့် တန်ဖိုးများထက် ပိုမိုများပြားလေ့ရှိပါသည်။ (မဖြစ်မှု) လီပ်တိုဂျင်နက်စစ်ကို ထည့်သွင်းခြင်းသည် theta_13 အပေါ် အပိုဆောင်းမှီခိုမှုကို မဖြစ်ပေါ်စေပါ။ သို့သော် BR(mu --> e, gamma) ၏ ပုံမှန်တန်ဖိုးကို လျှော့ချပေးပါသည်။
|
my
|
Recent studies indicated that helical organic molecules, such as DNA and $\alpha$-helical protein, can behave as Thouless quantum pumps when a rotating electric field is applied perpendicularly to their helical axes. Here we investigate the influence of long-range hoppings on this topological pumping of electrons in single-helical organic molecules. Under variation of the long-range hoppings governed by a decay exponent $\mu$, we find an energy gap in the molecular band structure closes at a critical value $\mu_c$ of the decay exponent and reopens for $\mu$ deviating from $\mu_c$. The relevant bulk bands in a pumping cycle acquire different Chern numbers in the strong ($\mu<\mu_c$) and weak ($\mu>\mu_c$) long-range hopping regimes, with a sudden jump at criticality. This topological phase transition is also shown to separate two distinct behaviors of the midgap end states in the pumping process. The end states carry quantized current pumped by the rotating electric field and the current forms a plateau by sweeping the Fermi energy over the gap. In the strong hopping phase, the quantized current plateau is positive, which is reversed to a negative one with smaller amplitude in the weak hopping phase. However, the reversal is a smooth crossover, not a sharp transition, due to the finite sizes of the molecules. We show that these transport characteristics of the topological phase transition could also be observed at finite temperatures.
|
সদ্য পরিচালিত কয়েকটি গবেষণায় উল্লেখ করা হয়েছে যে ডিএনএ এবং $\alpha$-হেলিকাল প্রোটিনের মতো হেলিকাল জৈব অণুগুলি থাউলেস কোয়ান্টাম পাম্পের মতো আচরণ করতে পারে যখন এদের হেলিকাল অক্ষের সাথে লম্বভাবে একটি ঘূর্ণনশীল তড়িৎক্ষেত্র প্রয়োগ করা হয়। এখানে আমরা একক হেলিকাল জৈব অণুতে ইলেকট্রনের এই টপোলজিক্যাল পাম্পিং-এ দীর্ঘ-পাল্লার হপিংয়ের প্রভাব নিয়ে গবেষণা করি। একটি হ্রাসমান সূচক $\mu$ দ্বারা নিয়ন্ত্রিত দীর্ঘ-পাল্লার হপিংয়ের পরিবর্তনের সাথে সাথে আমরা পাই যে অণুর ব্যান্ড গঠনে একটি শক্তি ফাঁক হ্রাসমান সূচকের একটি সংকটময় মান $\mu_c$-এ বন্ধ হয় এবং $\mu_c$ থেকে বিচ্যুত হওয়ার সাথে সাথে পুনরায় খুলে যায়। পাম্পিং চক্রে সংশ্লিষ্ট বাল্ক ব্যান্ডগুলি শক্তিশালী ($\mu<\mu_c$) এবং দুর্বল ($\mu>\mu_c$) দীর্ঘ-পাল্লার হপিং অঞ্চলে ভিন্ন চার্ন সংখ্যা লাভ করে, যেখানে সংকটময় মানে হঠাৎ লাফ দেখা যায়। পাম্পিং প্রক্রিয়ায় মধ্য-ফাঁকের শেষ অবস্থাগুলির দুটি আলাদা আচরণকে পৃথক করার জন্য এই টপোলজিক্যাল পর্যায় রূপান্তরটিও দেখানো হয়েছে। শেষ অবস্থাগুলি ঘূর্ণনশীল তড়িৎক্ষেত্র দ্বারা পাম্প করা কোয়ান্টাইজড তড়িৎপ্রবাহ বহন করে এবং ফাঁকের মধ্যে ফার্মি শক্তি পরিবর্তন করলে প্রবাহটি একটি সমতল গঠন করে। শক্তিশালী হপিং পর্যায়ে, কোয়ান্টাইজড প্রবাহের সমতলটি ধনাত্মক হয়, যা দুর্বল হপিং পর্যায়ে কম পরিমাণে ঋণাত্মক হয়ে উল্টে যায়। তবে, অণুগুলির সীমিত আকারের কারণে উল্টে যাওয়াটি একটি তীক্ষ্ণ রূপান্তর নয়, বরং একটি মসৃণ ক্রসওভার। আমরা দেখাই যে সীমিত তাপমাত্রাতেও এই টপোলজিক্যাল পর্যায় রূপান্তরের এই পরিবহন বৈশিষ্ট্যগুলি পর্যবেক্ষণ করা যেতে পারে।
|
bn
|
Swift discovered GRB 050713A and slewed promptly to begin observing with its narrow field instruments 72.6 seconds after the burst onset, while the prompt gamma-ray emission was still detectable in the BAT. Simultaneous emission from two flares is detected in the BAT and XRT. This burst marks just the second time that the BAT and XRT have simultaneously detected emission from a burst and the first time that both instruments have produced a well sampled, simultaneous dataset covering multiple X-ray flares. The temporal rise and decay parameters of the flares are consistent with the internal shock mechanism. In addition to the Swift coverage of GRB 050713A, we report on the Konus-Wind (K-W) detection of the prompt emission in the energy range 18-1150 keV, an upper limiting GeV measurement of the prompt emission made by the MAGIC imaging atmospheric Cherenkov telescope and XMM-Newton observations of the afterglow. Simultaneous observation between Swift XRT and XMM-Newton produce consistent results, showing a break in the lightcurve at T+~15ks. Together, these four observatories provide unusually broad spectral coverage of the prompt emission and detailed X-ray follow-up of the afterglow for two weeks after the burst trigger. Simultaneous spectral fits of K-W with BAT and BAT with XRT data indicate that an absorbed broken powerlaw is often a better fit to GRB flares than a simple absorbed powerlaw. These spectral results together with the rapid temporal rise and decay of the flares suggest that flares are produced in internal shocks due to late time central engine activity.
|
Swift mengesan GRB 050713A dan segera melakukan slew untuk mula membuat pemerhatian dengan instrumen medan sempitnya 72.6 saat selepas permulaan letupan, ketika pancaran sinar-gamma awal masih dapat dikesan oleh BAT. Pancaran serentak daripada dua nyalaan dikesan oleh BAT dan XRT. Letupan ini menandakan kali kedua sahaja BAT dan XRT secara serentak mengesan pancaran daripada satu letupan, dan kali pertama kedua-dua instrumen itu menghasilkan set data serentak yang dikumpul dengan baik merangkumi pelbagai nyalaan sinar-X. Parameter kenaikan dan penghuraian masa nyalaan adalah konsisten dengan mekanisme kejutan dalaman. Selain liputan Swift terhadap GRB 050713A, kami melaporkan pengesanan pancaran awal oleh Konus-Wind (K-W) dalam julat tenaga 18–1150 keV, ukuran had atas GeV terhadap pancaran awal yang dibuat oleh teleskop Cherenkov atmosfera imej MAGIC, dan pemerhatian XMM-Newton terhadap pancaran susulan. Pemerhatian serentak antara XRT Swift dan XMM-Newton menghasilkan keputusan yang konsisten, menunjukkan pecahan dalam lengkung cahaya pada T+~15ks. Secara keseluruhan, keempat-empat observatori ini menyediakan liputan spektrum yang luar biasa luas terhadap pancaran awal dan susulan terperinci sinar-X selama dua minggu selepas pencetus letupan. Penyesuaian spektrum serentak K-W dengan data BAT dan BAT dengan data XRT menunjukkan bahawa kuasa hukum patah terlarap sering memberikan penyesuaian yang lebih baik kepada nyalaan GRB berbanding kuasa hukum tunggal terlarap. Keputusan spektrum ini bersama-sama dengan kenaikan dan penghuraian masa nyalaan yang pantas mencadangkan bahawa nyalaan dihasilkan melalui kejutan dalaman akibat aktiviti enjin pusat pada fasa kemudian.
|
ms
|
Using the fact that flat space with a boundary is related by a Weyl transformation to anti-de Sitter (AdS) space, one may study observables in boundary conformal field theory (BCFT) by placing a CFT in AdS. In addition to correlation functions of local operators, a quantity of interest is the free energy of the CFT computed on the AdS space with hyperbolic ball metric, i.e. with a spherical boundary. It is natural to expect that the AdS free energy can be used to define a quantity that decreases under boundary renormalization group (RG) flows. We test this idea by discussing in detail the case of the large $N$ critical $O(N)$ model in general dimension $d$, as well as its perturbative descriptions in the epsilon-expansion. Using the AdS approach, we recover the various known boundary critical behaviors of the model, and we compute the free energy for each boundary fixed point, finding results which are consistent with the conjectured $F$-theorem in a continuous range of dimensions. Finally, we also use the AdS setup to compute correlation functions and extract some of the BCFT data. In particular, we show that using the bulk equations of motion, in conjunction with crossing symmetry, gives an efficient way to constrain bulk two-point functions and extract anomalous dimensions of boundary operators.
|
یہ بات استعمال کرتے ہوئے کہ ایک سرحد والی تخت جگہ کو اینٹی ڈی سٹر (ایڈی ایس) جگہ سے ایک ویل تبدیلی کے ذریعے مربوط کیا جا سکتا ہے، باؤنڈری کانفارمل فیلڈ تھیوری (بی سی ایف ٹی) میں مشاہداتی اقدار کا مطالعہ ایڈی ایس میں ایک سی ایف ٹی رکھ کر کیا جا سکتا ہے۔ مقامی آپریٹرز کی تعلقیاتی افعال کے علاوہ، ایک دلچسپ مقدار وہ فری انرجی ہے جو ہائپربولک بال میٹرک والی ایڈی ایس جگہ پر سی ایف ٹی کی حساب کتاب کی جاتی ہے، یعنی کروی سرحد کے ساتھ۔ یہ توقع کرنا قدرتی ہے کہ باؤنڈری رینورملائزیشن گروپ (آر جی) فلو کے تحت کم ہونے والی مقدار کی تعریف کے لیے ایڈی ایس فری انرجی کا استعمال کیا جا سکتا ہے۔ ہم اس خیال کی جانچ مختلف بعد d میں بڑے N اہم O(N) ماڈل کے معاملے کو تفصیل سے بحث کر کے کرتے ہیں، اس کے علاوہ ایپسیلون توسیع میں اس کی تفریقی وضاحتوں کا بھی جائزہ لیتے ہیں۔ ایڈی ایس کے نقطہ نظر کا استعمال کرتے ہوئے، ہم ماڈل کے مختلف معلوم باؤنڈری اہم رویے کو حاصل کرتے ہیں، اور ہر باؤنڈری فکسڈ پوائنٹ کے لیے فری انرجی کا حساب لگاتے ہیں، جس سے ابعاد کی مسلسل حد تک فرضیہ F-تھیورم کے ساتھ مطابقت رکھنے والے نتائج حاصل ہوتے ہیں۔ آخر میں، ہم بی سی ایف ٹی کے ڈیٹا کو حاصل کرنے کے لیے مشاہداتی افعال کی حساب کتاب کے لیے ایڈی ایس سیٹ اپ کا بھی استعمال کرتے ہیں۔ خاص طور پر، ہم دکھاتے ہیں کہ بیچ کے مساوات حرکت کا استعمال، کراسنگ سمتی کے ساتھ مل کر، بیچ کے دو اشارہ افعال کو محدود کرنے اور باؤنڈری آپریٹرز کے غیر معمولی بعد حاصل کرنے کا ایک موثر طریقہ ہے۔
|
ur
|
The Doppler dipole signal dominates the cosmic microwave background (CMB) anisotropy maps obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) mission, and plays a key role throughout the data processing. Previously, we discovered a timing asynchronism of -25.6ms between the timestamps of the spacecraft attitude and radiometer output in the original raw WMAP time-ordered data (TOD), which, if not corrected in following data processing, would generate an artificial quadrupole component (l=2) in recovered CMB maps (Liu, Xiong & Li 2010). Recently, Roukema (2010b) proves that there does exist a timing-offset-induced error corresponding to about -25.6ms in the WMAP calibrated TOD by studying the fluctuation variance per pixel in the temperature map recovered from the TOD as a function of assumed timing-offset. Here, we find evidence directly in the WMAP TOD for such an uncorrected timing error, possibly occurred in calculating the Doppler dipole signal during the WMAP team's TOD data processing. The amplitude is highly significant and is consistent with previous work. We also show that the uncorrected timing-offset can lead the WMAP CMB quadrupole to be substantially overestimated.
|
Le signal du dipôle Doppler domine les cartes d'anisotropie du fond diffus cosmologique (CMB) obtenues par la mission Wilkinson Microwave Anisotropy Probe (WMAP), et joue un rôle clé tout au long du traitement des données. Précédemment, nous avons découvert un décalage temporel de -25,6 ms entre les horodatages de l'orientation du vaisseau spatial et la sortie des radiomètres dans les données brutes initiales de WMAP (TOD), lequel, s'il n'est pas corrigé lors du traitement ultérieur des données, générerait une composante quadrupolaire artificielle (l=2) dans les cartes CMB reconstruites (Liu, Xiong & Li 2010). Récemment, Roukema (2010b) a démontré qu'il existe effectivement une erreur induite par un décalage temporel correspondant à environ -25,6 ms dans les données TOD calibrées de WMAP, en étudiant la variance des fluctuations par pixel dans la carte de température reconstruite à partir des données TOD en fonction du décalage temporel supposé. Ici, nous trouvons une preuve directe, dans les données TOD de WMAP, d'une telle erreur de synchronisation non corrigée, survenue probablement lors du calcul du signal du dipôle Doppler au cours du traitement des données TOD par l'équipe WMAP. L'amplitude est très significative et concorde avec les travaux antérieurs. Nous montrons également qu'un décalage temporel non corrigé peut entraîner une surestimation substantielle du quadrupôle CMB de WMAP.
|
fr
|
Groundwater is a precious natural resource. Groundwater level (GWL) forecasting is crucial in the field of water resource management. Measurement of GWL from observation-wells is the principle source of information about the aquifer and is critical to its evaluation. Most part of the Udupi district of Karnataka State in India consists of geological formations: lateritic terrain and gneissic complex. Due to the topographical ruggedness and inconsistency in rainfall, the GWL in Udupi region is declining continually and most of the open wells are drying-up during the summer. Hence, the current research aimed at developing a groundwater level forecasting model by using hybrid Long Short-term Memory-Lion Algorithm (LSTM-LA). The historical GWL and rainfall data from an observation well from Udupi district, located in Karnataka state, India, were used to develop the model. The prediction accuracy of the hybrid LSTM-LA model was better than that of the Feedforward Neural network (FFNN) and the isolated LSTM models. The hybrid LSTM-LA based forecasting model is promising for a larger dataset.
|
ទឹកក្រោមដីគឺជាធនធានធម្មជាតិដ៏មានតម្លៃ។ ការទស្សន៍ទាយកម្រិតទឹកក្រោមដី (GWL) គឺជាកត្តាសំខាន់នៅក្នុងវិស័យគ្រប់គ្រងធនធានទឹក។ ការវាស់វែងកម្រិតទឹកក្រោមដីពីកន្លែងសង្កេតការណ៍គឺជាប្រភពព័ត៌មានសំខាន់បំផុតអំពីអាកុយអ៊ឺរ៍ ហើយវាមានសារៈសំខាន់ខាងការវាយតម្លៃ។ ភាគច្រើននៃស្រុកអ៊្វ៉េឌូពី នៃរដ្ឋការ៉ណាតកៈ នៅប្រទេសឥណ្ឌា មានរូបរាងភូមិសាស្ត្រ៖ ដីប៉ុស្តិ៍ និងស្មុគស្មាញនៃថ្មហួត។ ដោយសារតែភាពអាក្រក់នៃរូបរាងដី និងភាពមិនស្ថិតស្ថេរនៃបរិមាណទឹកភ្លៀង កម្រិតទឹកក្រោមដីនៅតំបន់អ៊្វ៉េឌូពីកំពុងធ្លាក់ចុះជាបន្តបន្ទាប់ ហើយភាគច្រើននៃប្រភទកន្លែងដែលបើកចំហ កំពុងស្ងួតនៅរដូវក្តៅ។ ដូច្នេះ ការស្រាវជ្រាវបច្ចុប្បន្ននេះ មានគោលបំណងបង្កើតគំរូទស្សន៍ទាយកម្រិតទឹកក្រោមដី ដោយប្រើប្រាស់ប្រព័ន្ធប្រវត្តិរយៈពេលខ្លី-វែង លាយឡំជាមួយនឹងក្បួនដោះស្រាយសេវ៉ា (LSTM-LA)។ ទិន្នន័យប្រវត្តិសាស្ត្រនៃកម្រិតទឹកក្រោមដី និងទឹកភ្លៀងពីកន្លែងសង្កេតការណ៍មួយក្នុងស្រុកអ៊្វ៉េឌូពី ដែលស្ថិតនៅរដ្ឋការ៉ណាតកៈ ប្រទេសឥណ្ឌា ត្រូវបានប្រើដើម្បីបង្កើតគំរូនេះ។ ភាពត្រឹមត្រូវនៃការទស្សន៍ទាយរបស់គំរូលាយឡំ LSTM-LA គឺល្អជាងគំរូបណ្តាញប្រសព្វប្រទាន (FFNN) និងគំរូ LSTM ដែលដាច់ដោយឡែក។ គំរូទស្សន៍ទាយដែលផ្អែកលើប្រព័ន្ធលាយឡំ LSTM-LA គឺសន្យាល្អសម្រាប់ការប្រើប្រាស់ជាមួយទិន្នន័យច្រើន។
|
km
|
A new wave of decision-support systems are being built today using AI services that draw insights from data (like text and video) and incorporate them in human-in-the-loop assistance. However, just as we expect humans to be ethical, the same expectation needs to be met by automated systems that increasingly get delegated to act on their behalf. A very important aspect of an ethical behavior is to avoid (intended, perceived, or accidental) bias. Bias occurs when the data distribution is not representative enough of the natural phenomenon one wants to model and reason about. The possibly biased behavior of a service is hard to detect and handle if the AI service is merely being used and not developed from scratch, since the training data set is not available. In this situation, we envisage a 3rd party rating agency that is independent of the API producer or consumer and has its own set of biased and unbiased data, with customizable distributions. We propose a 2-step rating approach that generates bias ratings signifying whether the AI service is unbiased compensating, data-sensitive biased, or biased. The approach also works on composite services. We implement it in the context of text translation and report interesting results.
|
Isang bagong alon ng mga sistema ng suporta sa desisyon ang kasalukuyang itinatayo gamit ang mga serbisyong AI na kumuha ng mga insight mula sa datos (tulad ng teksto at video) at isinasama ang mga ito sa tulong kung saan kasali ang tao. Gayunpaman, tulad ng pag-asa natin sa mga tao na maging etikal, ang parehong inaasahan ay dapat matugunan ng mga awtomatikong sistema na unti-unting pinapagawa upang kumilos sa kanilang ngalan. Ang isang napakahalagang aspeto ng etikal na pag-uugali ay ang pag-iwas sa bias (sinadya, napapansin, o aksidental). Ang bias ay nangyayari kapag ang distribusyon ng datos ay hindi sapat na kumakatawan sa likas na penomenong nais modelohin at bigyang-katwiran. Mahirap tukuyin at harapin ang posibleng may bias na pag-uugali ng isang serbisyo kung ang serbisyong AI ay ginagamit lamang at hindi binuo mula sa simula, dahil hindi available ang dataset na ginamit sa pagsanay. Sa sitwasyong ito, isinasapuso namin ang isang rating agency mula sa ikatlong partido na malaya sa tagagawa o tagagamit ng API at may sariling hanay ng may bias at walang bias na datos, na may mga distribusyon na maaaring i-customize. Iminumungkahi namin ang isang dalawahang hakbang na pamamaraan sa pagrarate na lumilikha ng mga rating ng bias upang ipahiwatig kung ang serbisyong AI ay walang bias at kompensado, sensitibo sa datos ngunit may bias, o may bias. Ang pamamaraan ay gumagana rin sa mga kompositong serbisyo. Ito ay aming isinagawa sa konteksto ng pagsasalin ng teksto at inilahad ang ilang kawili-wiling resulta.
|
tl
|
Recent radio images of the BL Lac object ON231 (W Com, 1219+285) show remarkable new features in the source structure compared to those previously published. The images were obtained from observations made with the European VLBI Network plus MERLIN at 1.6 GHz and 5 GHz after the exceptional optical outburst occurred in Spring 1998. The up-to-date B band historic light curve of ON231 is also presented together with the R band luminosity evolution in the period 1994--1999. We identify the source core in the radio images with the brightest component having the flattest spectrum. A consequence of this assumption is the existence of a two--sided emission in ON231 not detected in previous VLBI images. A further new feature is a large bend in the jet at about 10 mas from the core. The emission extends for about 20 mas after the bend, which might be due to strong interaction with the environment surrounding the nucleus. We suggest some possible interpretations to relate the changes in the source structure with the optical and radio flux density variation in the frame of the unification model.
|
Nedávné rádiové snímky objektu BL Lac ON231 (W Com, 1219+285) ukazují výrazné nové rysy ve struktuře zdroje ve srovnání s dříve publikovanými. Snímky byly získány pozorováním pomocí Evropské sítě VLBI a MERLINu na frekvencích 1,6 GHz a 5 GHz po výjimečném optickém výbuchu, ke kterému došlo na jaře 1998. Je rovněž prezentována aktuální historická světelná křivka ON231 v pásmu B spolu s vývojem jasnosti v pásmu R v období 1994–1999. Jádro zdroje na rádiových snímcích identifikujeme s nejjasnější komponentou s nejrovnanějším spektrem. Důsledkem tohoto předpokladu je existence dvoustranné emise v ON231, která nebyla v předchozích VLBI snímcích pozorována. Dalším novým rysem je výrazný ohyb v proudu na vzdálenosti přibližně 10 mas od jádra. Emise pokračuje po ohybu asi po vzdálenost 20 mas, což může být způsobeno silnou interakcí s prostředím obklopujícím jádro. Navrhujeme některé možné interpretace, které vysvětlují změny ve struktuře zdroje ve vztahu k variacím optické a rádiové hustoty toku v rámci modelu unifikace.
|
cs
|
When building a global brand of any kind -- a political actor, clothing style, or belief system -- developing widespread awareness is a primary goal. Short of knowing any of the stories or products of a brand, being talked about in whatever fashion -- raw fame -- is, as Oscar Wilde would have it, better than not being talked about at all. Here, we measure, examine, and contrast the day-to-day raw fame dynamics on Twitter for US Presidents and major US Presidential candidates from 2008 to 2020: Barack Obama, John McCain, Mitt Romney, Hillary Clinton, Donald Trump, and Joe Biden. We assign ``lexical fame'' to be the number and (Zipfian) rank of the (lowercased) mentions made for each individual across all languages. We show that all five political figures have at some point reached extraordinary volume levels of what we define to be ``lexical ultrafame'': An overall rank of approximately 300 or less which is largely the realm of function words and demarcated by the highly stable rank of `god'. By this measure, `trump' has become enduringly ultrafamous, from the 2016 election on. We use typical ranks for country names and function words as standards to improve perception of scale. We quantify relative fame rates and find that in the eight weeks leading up the 2008 and 2012 elections, `obama' held a 1000:757 volume ratio over `mccain' and 1000:892 over `romney', well short of the 1000:544 and 1000:504 volumes favoring `trump' over `hillary' and `biden' in the 8 weeks leading up to the 2016 and 2020 elections. Finally, we track how only one other entity has more sustained ultrafame than `trump' on Twitter: The K-pop (Korean pop) band BTS. We chart the dramatic rise of BTS, finding their Twitter handle `@bts\_twt' has been able to compete with `a' and `the'. Our findings for BTS more generally point to K-pop's growing economic, social, and political power.
|
မည်သည့်အမျိုးအစား ကမ္ဘာလုံးဆိုင်ရာ အမှတ်တံဆိပ်တစ်ခုကိုမဆို တည်ဆောက်ရာတွင်—နိုင်ငံရေးသမား၊ အဝတ်အစားစတိုင် သို့မဟုတ် ယုံကြည်မှုစနစ်— ကျယ်ပြန့်စွာ သတိပြုမိမှုကို ဖွံ့ဖြိုးတိုးတက်စေရန်သည် အဓိကရည်မှန်းချက်ဖြစ်သည်။ အမှတ်တံဆိပ်၏ ဇာတ်လမ်း သို့မဟုတ် ထုတ်ကုန်များကို သိရှိမှုမရှိဘဲ မည်သည့်နည်းနှင့်မဆို ဆွေးနွေးပြောဆိုခြင်း— ရိုးရှင်းသော ကျော်ကြားမှု— သည် အိုစကာ့ဝိုက်ဒ် ပြောသလို လုံးဝ မပြောဆိုခြင်းထက် ပိုကောင်းပါသည်။ ဤနေရာတွင် ၂၀၀၈ မှ ၂၀၂၀ အထိ အမေရိကန်သမ္မတများနှင့် အဓိက အမေရိကန်သမ္မတလောင်းများဖြစ်သည့် ဘာရက်အိုဘားမား၊ ဂျွန်မက်ကိန်း၊ မစ်ရိုမီးနီ၊ ဟီလာရီခလင်တန်၊ ဒေါ်နယ်ထရမ့်နှင့် ဂျိုဘိုင်ဒင်တို့အတွက် တွစ်တာတွင် နေ့စဥ် ရိုးရှင်းသော ကျော်ကြားမှု အပြောင်းအလဲများကို တိုင်းတာ၍ စစ်ဆေး နှိုင်းယှဉ်ပါသည်။ တစ်ဦးချင်းစီကို ဘာသာစကားအားလုံးတွင် ဖော်ပြမှုအရေအတွက်နှင့် (ဇစ်ဘ်းဖီယန်) အဆင့်အတန်းကို အသုံးပြု၍ ကျွန်ုပ်တို့သည် "အသံဖလှယ်မှု ကျော်ကြားမှု" ကို သတ်မှတ်ပါသည်။ ကျွန်ုပ်တို့သည် လုပ်ဆောင်ချက်စကားလုံးများ၏ နယ်ပယ်ဖြစ်ပြီး `god` ၏ အလွန်တည်ငြိမ်သော အဆင့်အတန်းဖြင့် သတ်မှတ်ထားသည့် စုစုပေါင်းအဆင့် ၃၀၀ နီးပါး သို့မဟုတ် ထို့ထက်နည်းသည့် အဆင့်ကို သတ်မှတ်ကာ ကျွန်ုပ်တို့ သတ်မှတ်ထားသည့် "အသံဖလှယ်မှု အလွန်ကျော်ကြားမှု" ၏ များပြားလွန်းသော အဆင့်များသို့ နိုင်ငံရေးသမားငါးဦးလုံးသည် အချိန်တစ်ခုခုတွင် ရောက်ရှိခဲ့ကြကြောင်း ပြသပါသည်။ ဤနည်းအားဖြင့် `trump` သည် ၂၀၁၆ ရွေးကောက်ပွဲမှစ၍ ကာလရှည် အလွန်ကျော်ကြားလာခဲ့ပါသည်။ အဆင့်အတန်း၏ အရွယ်အစားကို ပိုမိုနားလည်ရန် နိုင်ငံအမည်များနှင့် လုပ်ဆောင်ချက်စကားလုံးများ၏ ပုံမှန်အဆင့်အတန်းများကို စံနှုန်းများအဖြစ် အသုံးပြုပါသည်။ ဆက်စပ်ကျော်ကြားမှုနှုန်းများကို တိုင်းတာရာတွင် ၂၀၀၈ နှင့် ၂၀၁၂ ရွေးကောက်ပွဲများကို ဦးတည်သော ရက်သတ္တပတ်ရှစ်ပတ်အတွင်း `obama` သည် `mccain` ကို ၁၀၀၀:၇၅၇ အချိုးနှီးဖြင့် နှင့် `romney` ကို ၁၀၀၀:၈၉၂ အချိုးနှီးဖြင့် ကျော်လွန်နေပြီး ၂၀၁၆ နှင့် ၂၀၂၀ ရွေးကောက်ပွဲများကို ဦးတည်သော ရက်သတ္တပတ်ရှစ်ပတ်အတွင်း `trump` သည် `hillary` နှင့် `biden` ကို ၁၀၀၀:၅၄၄ နှင့် ၁၀၀၀:၅၀၄ အချိုးနှီးဖြင့် ကျော်လွန်နေသည့် အဆင့်ကို မရောက်ရှိသေးကြောင်း တွေ့ရှိရပါသည်။ နောက်ဆုံးအနေဖြင့် တွစ်တာတွင် `trump` ထက် ပိုမိုတည်ငြိမ်သော အလွန်ကျော်ကြားမှုရှိသည့် အင်တီတီတီတစ်ခုသာ ရှိကြောင်း ခြေရာခံတွေ့ရှိပါသည်။ ထိုအင်တီတီတီမှာ K-pop (ကိုရီးယားပေါ့) ဘန်း BTS ဖြစ်ပါသည်။ BTS ၏ အလွန်အမင်းတိုးတက်လာမှုကို ခြေရာခံပြီး ၎င်းတို့၏ တွစ်တာ လက်ကိုင်အမည် `@bts_twt` သည် `a` နှင့် `the` တို့နှင့် ယှဉ်ပြိုင်နိုင်ကြောင်း တွေ့ရှိပါသည်။ ယေဘုယျအားဖြင့် BTS အတွက် ကျွန်ုပ်တို့၏ ရှာဖွေတွေ့ရှိမှုများသည် K-pop ၏ စီးပွားရေး၊ လူမှုရေး နှင့် နိုင်ငံရေးအင်အား တိုးတက်လာမှုကို ညွှန်ပြနေပါသည်။
|
my
|
We use the SnIa Gold dataset to compare LCDM with 10 representative parametrizations of the recent Hubble expansion history $H(z)$. For the comparison we use two statistical tests; the usual $\chi_{min}^2$ which is insensitive to the parametrization number of parameters, and a statistic we call the p-test which depends on both the value of $\chi_{min}^2$ and the number $n$ of the parametrization parameters. The p-test measures the confidence level to which the parameter values corresponding to LCDM are excluded from the viewpoint of the parametrization tested. For example, for a linear equation of state parametrization $w(z)=w_0 + w_1 z$ the LCDM parameter values ($w_0=-1$, $w_1=0$) are excluded at 75% confidence level. We use a flat prior and $\Omega_{0m}=0.3$. All parametrizations tested are consistent with the Gold dataset at their best fit. According to both statistical tests, the worst fits among the 10 parametrizations, correspond to the Chaplygin gas, the brane world and the Cardassian parametrizations. The best fit is achieved by oscillating parametrizations which can exclude the parameter values corresponding to LCDM at 85% confidence level. Even though this level of significance does not provide a statistically significant exclusion of LCDM (it is less than $2\sigma$) and does not by itself constitute conclusive evidence for oscillations in the cosmological expansion, when combined with similar independent recent evidence for oscillations coming from the CMB and matter power spectra it becomes an issue worth of further investigation.
|
我们利用SnIa Gold数据集，将LCDM模型与10种代表性的哈勃膨胀历史参数化形式$H(z)$进行比较。在比较中，我们使用了两种统计检验方法：一种是通常的$\chi_{min}^2$检验，它对参数化形式的参数数量不敏感；另一种是我们称为p检验的统计量，它同时依赖于$\chi_{min}^2$的取值和参数化形式的参数数量$n$。p检验用于衡量从被检验的参数化形式的角度看，LCDM对应的参数值被排除的置信水平。例如，对于线性状态方程参数化形式$w(z)=w_0 + w_1 z$，LCDM的参数值（$w_0=-1$，$w_1=0$）在75%的置信水平下被排除。我们采用平坦先验，并设定$\Omega_{0m}=0.3$。所有被检验的参数化形式在其最佳拟合下均与Gold数据集相容。根据这两种统计检验，这10种参数化形式中拟合最差的是Chaplygin气体、膜世界和Cardassian参数化形式。最佳拟合由振荡型参数化形式实现，其可将对应于LCDM的参数值在85%的置信水平下排除。尽管这一显著性水平尚不足以在统计上明确排除LCDM（低于$2\sigma$），也不能单独构成宇宙膨胀中存在振荡的确凿证据，但当其与来自CMB和物质功率谱的类似独立的近期证据相结合时，这一问题便值得进一步研究。
|
zh
|
The surface phase behavior of binary mixtures of colloidal hard rods in contact with a solid substrate (hard wall) is studied, with special emphasis on the region of the phase diagram that includes the smectic A phase. The colloidal rods are modelled as hard cylinders of the same diameter and different lengths, in the approximation of perfect alignment. A fundamental--measure density functional is used to obtain equilibrium density profiles and thermodynamic properties such as surface tensions and adsorption coefficients. The bulk phase diagram exhibits nematic-smectic and smectic-smectic demixing, with smectic phases having different compositions; in some cases they are microfractionated. The calculated surface phase diagram of the wall-nematic interface shows a very rich phase behavior, including layering transitions and complete wetting at high pressures, whereby an infinitely thick smectic film grows at the wall via an infinite sequence of stepwise first--order layering transitions. For lower pressures complete wetting also obtains, but here the smectic film grows in a continuous fashion. Finally, at very low pressures, the wall-nematic interface exhibits critical adsorption by the smectic phase, due to the second-order character of the bulk nematic-smectic transition.
|
Исследуется поверхностное фазовое поведение бинарных смесей коллоидных жестких стержней, находящихся в контакте с твердой подложкой (жесткая стенка), с особым акцентом на область фазовой диаграммы, включающую фазу смектика A. Коллоидные стержни моделируются как жесткие цилиндры одинакового диаметра, но различной длины в приближении идеальной ориентационной упорядоченности. Для получения равновесных профилей плотности и термодинамических свойств, таких как поверхностное натяжение и коэффициенты адсорбции, используется функционал плотности на основе фундаментальных мер. Объемная фазовая диаграмма демонстрирует расслоение на нематик-смектик и смектик-смектик, причем смектические фазы имеют различный состав; в некоторых случаях наблюдается микродробление. Рассчитанная поверхностная фазовая диаграмма границы раздела стенка-нематик показывает чрезвычайно разнообразное фазовое поведение, включая переходы слоения и полное смачивание при высоких давлениях, при котором на стенке образуется бесконечно толстая пленка смектика посредством бесконечной последовательности ступенчатых фазовых переходов первого рода. При более низких давлениях полное смачивание также имеет место, однако в этом случае пленка смектика растет непрерывным образом. Наконец, при очень низких давлениях граница раздела стенка-нематик демонстрирует критическую адсорбцию со стороны смектической фазы, обусловленную характером объемного фазового перехода второго рода между нематической и смектической фазами.
|
ru
|
Purpose: To understand the influence of various acquisition parameters on the ability of CEST MR-Fingerprinting (MRF) to discriminate different chemical exchange parameters and to provide tools for optimal acquisition schedule design and parameter map reconstruction. Methods: Numerical simulations were conducted using a parallel-computing implementation of the Bloch-McConnell equations, examining the effect of TR, TE, flip-angle, water T$_{1}$ and T$_{2}$, saturation-pulse duration, power, and frequency on the discrimination ability of CEST-MRF. A modified Euclidean-distance matching metric was evaluated and compared to traditional dot-product matching. L-Arginine phantoms of various concentrations and pH were scanned at 4.7T and the results compared to numerical findings. Results: Simulations for dot-product matching demonstrated that the optimal flip-angle and saturation times are 30$^{\circ}$ and 1100 ms, respectively. The optimal maximal saturation power was 3.4 $\mu$T for concentrated solutes with a slow exchange-rate, and 5.2 $\mu$T for dilute solutes with medium-to-fast exchange-rates. Using the Euclidean-distance matching metric, much lower maximum saturation powers were required (1.6 and 2.4 $\mu$T, respectively), with a slightly longer saturation time (1500 ms) and 90$^{\circ}$ flip-angle. For both matching metrics, the discrimination ability increased with the repetition time. The experimental results were in agreement with simulations, demonstrating that more than a 50% reduction in scan-time can be achieved by Euclidean-distance-based matching. Conclusion: Optimization of the CEST-MRF acquisition schedule is critical for obtaining the best exchange parameter accuracy. The use of Euclidean-distance-based matching of signal trajectories simultaneously improved the discrimination ability and reduced the scan time and maximal saturation power required.
|
Objetivo: Comprender la influencia de diversos parámetros de adquisición en la capacidad de la resonancia magnética con huella de intercambio químico (CEST-MRF) para discriminar diferentes parámetros de intercambio químico y proporcionar herramientas para el diseño óptimo del protocolo de adquisición y la reconstrucción de mapas de parámetros. Métodos: Se realizaron simulaciones numéricas utilizando una implementación paralela de las ecuaciones de Bloch-McConnell, examinando el efecto del TR, TE, ángulo de giro, tiempos T$_{1}$ y T$_{2}$ del agua, duración, potencia y frecuencia del pulso de saturación sobre la capacidad de discriminación del CEST-MRF. Se evaluó una métrica modificada de coincidencia por distancia euclidiana y se comparó con la coincidencia tradicional por producto escalar. Se escanearon fantasmas de L-arginina con diversas concentraciones y pH a 4,7 T, y los resultados se compararon con los hallazgos numéricos. Resultados: Las simulaciones con coincidencia por producto escalar mostraron que el ángulo de giro óptimo y el tiempo de saturación óptimo son 30$^{\circ}$ y 1100 ms, respectivamente. La potencia máxima óptima de saturación fue de 3,4 $\mu$T para solutos concentrados con tasas lentas de intercambio, y de 5,2 $\mu$T para solutos diluidos con tasas de intercambio medias a rápidas. Utilizando la métrica de coincidencia por distancia euclidiana, se requirieron potencias máximas de saturación mucho menores (1,6 y 2,4 $\mu$T, respectivamente), con un tiempo de saturación ligeramente mayor (1500 ms) y un ángulo de giro de 90$^{\circ}$. Para ambas métricas de coincidencia, la capacidad de discriminación aumentó con el tiempo de repetición. Los resultados experimentales coincidieron con las simulaciones, demostrando que mediante la coincidencia basada en la distancia euclidiana se puede lograr una reducción superior al 50 % en el tiempo de escaneo. Conclusión: La optimización del protocolo de adquisición del CEST-MRF es fundamental para obtener la máxima precisión en los parámetros de intercambio. El uso de la coincidencia basada en la distancia euclidiana de las trayectorias de señal mejoró simultáneamente la capacidad de discriminación, redujo el tiempo de escaneo y disminuyó la potencia máxima de saturación requerida.
|
es
|
We compute the first curvature corrections to the spectrum of light-cone gauge type IIA string theory that arise in the expansion of $AdS_4\times \mathbb{CP}^3$ about a plane-wave limit. The resulting spectrum is shown to match precisely, both in magnitude and degeneration that of the corresponding solutions of the all-loop Gromov--Vieira Bethe Ansatz. The one-loop dispersion relation correction is calculated for all the single oscillator states of the theory, with the level matching condition lifted. It is shown to have all logarithmic divergences cancelled and to leave only a finite exponentially suppressed contribution, as shown earlier for light bosons. We argue that there is no ambiguity in the choice of the regularization for the self-energy sum, since the regularization applied is the only one preserving unitarity. Interaction matrices in the full degenerate two-oscillator sector are calculated and the spectrum of all two light magnon oscillators is completely determined. The same finite-size corrections, at the order 1/J, where $J$ is the length of the chain, in the two-magnon sector are calculated from the all loop Bethe Ansatz. The corrections obtained by the two completely different methods coincide up to the fourth order in $\lambda' =\lambda/J^2$. We conjecture that the equivalence extends to all orders in $\lambda$ and to higher orders in 1/J.
|
យើងគណនាការកែតម្រូវនៃកំណាត់ដំបូងទៅលើវគ្គពន្លឺនៃទ្រឹស្តីខ្សែបែប IIA ក្នុងប្រព័ន្ធមាត្រា light-cone ដែលកើតឡើងក្នុងការពង្រីក $AdS_4\times \mathbb{CP}^3$ អំពីដែនកំណត់រលកយន្តហោះ។ វគ្គពន្លឺដែលទទួលបានបង្ហាញថាពិតប្រាកដត្រូវគ្នាទាំងទំហំ និងការបំបែកដែលស្របគ្នាជាមួយដំណោះស្រាយដែលពាក់ព័ន្ធនៃសមីការប្រមាណវិធី Bethe គ្រប់វដ្ត Gromov--Vieira។ ការកែតម្រូវទំនាក់ទំនងរាយការណ៍មួយវដ្តត្រូវបានគណនាសម្រាប់រដ្ឋរំញ័រតែមួយទាំងអស់នៃទ្រឹស្តី ដោយលើកលែងលក្ខខណ្ឌផ្គូផ្គងកម្រិត។ វាត្រូវបានបង្ហាញថាមានការលុបចោលទាំងស្រុងនូវភាពប៉ះពាល់ឡូហ្គារីត ហើយទុកចោលតែការរួមចំណែកដែលត្រូវបានគេបន្ថយដោយអ៊ិចស្ប៉ូណង់ស្យែល ដូចដែលបានបង្ហាញពីមុនសម្រាប់ផូតុងពន្លឺ។ យើងអះអាងថាគ្មានភាពច្របូកច្របល់អំពីការជ្រើសរើសការកំណត់រចនាសម្ព័ន្ធសម្រាប់ផលបូកថាមពលខ្លួនឯងទេ ដោយសារការកំណត់រចនាសម្ព័ន្ធដែលអនុវត្តគឺជាការតែមួយគត់ដែលរក្សាភាពត្រឹមត្រូវ។ ម៉ាទ្រីសអន្តរកម្មក្នុងផ្នែករំញ័រពីរដែលបំបែកទាំងស្រុងត្រូវបានគណនា ហើយវគ្គពន្លឺរបស់រំញ័រពន្លឺម៉ាញ៉េតុងពីរទាំងអស់ត្រូវបានកំណត់យ៉ាងពេញលេញ។ ការកែតម្រូវទំហំតូចដូចគ្នានៅកម្រិត 1/J ដែល J គឺជាប្រវែងនៃខ្សែ ក្នុងផ្នែកម៉ាញ៉េតុងពីរត្រូវបានគណនាពីសមីការប្រមាណវិធី Bethe គ្រប់វដ្ត។ ការកែតម្រូវដែលទទួលបានដោយវិធីសាស្ត្រពីរដែលខុសគ្នាទាំងស្រុងគ្នានេះ ពិតប្រាកដត្រូវគ្នាលើការ៉េទីបួនក្នុង $\lambda' =\lambda/J^2$។ យើងសន្មតថាភាពស្មើគ្នានេះពង្រីកទៅគ្រប់កម្រិតនៅក្នុង $\lambda$ និងទៅកម្រិតខ្ពស់ជាងនៅក្នុង 1/J។
|
km
|
We report a fully quantum-dynamical study of the intramolecular vibrational energy redistribution (IVR) in the electronic ground state of carbonyl sulfide (OCS), which is a prototype of an isolated many-body quantum system with strong internal couplings and non-Rice-Ramsperger-Kassel-Marcus (RRKM) behavior. We pay particular attention to the role of many-body localization and the approach to thermalization, which currently are topics of considerable interest, as they pertain to the very foundations of statistical mechanics and thermodynamics. We employ local-mode (valence) coordinates and consider initial excitations localized in one local mode, with energies ranging from low to near the dissociation threshold, where the classical dynamics have been shown to be chaotic. We propagate the nuclear wavepacket on the potential energy surface by means of the numerically exact multiconfiguration time-dependent Hartree method and employ mean local energies, time-dependent and time-averaged populations in quantum number space, energy distributions, entanglement entropies, local population distributions, microcanonical averages, and dissociation probabilities, as diagnostic tools. This allows us to identify a continuous localization $\rightarrow$ delocalization transition in the energy flow, associated with the onset of quantum chaos, as the excitation energy increases up to near the dissociation threshold. Moreover, we find that at this energy and $\sim$1 ps the molecule nearly thermalizes. Furthermore, we observe that IVR is so slow that the molecule begins to dissociate well before such quasi-thermalization is complete, in accordance with earlier classical-mechanical predictions of non-RRKM behavior.
|
نُبلِغ عن دراسة كمومية ديناميكية كاملة لإعادة توزيع الطاقة الاهتزازية داخل الجزيء (IVR) في الحالة الإلكترونية الأساسية لمركب كربونيل سلفيد (OCS)، الذي يُعد نموذجًا مثاليًا لنظام كمومي معزول متعدد الأجسام يتميز بروابط داخلية قوية وسلوك غير تابع لنموذج رايس-رامسبرغر-كاسل-ماركوس (RRKM). ونولي اهتمامًا خاصًا لدور التموضع المتعدد الأجسام (many-body localization) والاقتراب من حالة التوازن الحراري، وهي موضوعات تحظى حاليًا باهتمام بالغ، نظرًا لارتباطها بالأسس نفسها للديناميكا الإحصائية والحرارية. نستخدم إحداثيات الوضع الموضعي (valence) وننظر في اهتياجات أولية متمركزة في وضع موضعي واحد، بمستويات طاقة تتراوح من المنخفضة وحتى القريبة من حد التفكك، حيث أُثبت أن السلوك الديناميكي الكلاسيكي يكون فوضويًا. نُجري تطور الحزمة الموجية النووية على سطح طاقة الوضع باستخدام طريقة هارتري المعتمدة على التكوين المتعدد (multiconfiguration time-dependent Hartree) الدقيقة عدديًا، ونستخدم كأدوات تشخيصية: الطاقات المحلية المتوسطة، والتعدادات المعتمدة على الزمن والمتوسطة زمنيًا في فضاء الأعداد الكمومية، وتوزيعات الطاقة، وانتروبيات التشابك، وتوزيعات التعداد المحلي، والمتوسطات الميكروكانونية، واحتمالات التفكك. ويتيح لنا هذا التحليل التعرف على انتقال مستمر من التموضع إلى الانتشار في تدفق الطاقة، يرتبط بظهور الفوضى الكمية، مع زيادة طاقة الاهتياج حتى تقترب من حد التفكك. علاوةً على ذلك، نجد أنه عند هذه الطاقة وعند زمن يقارب 1 بيكسو ثانية (ps)، يقترب الجزيء من حالة التوازن الحراري تقريبًا. وبالإضافة إلى ذلك، نلاحظ أن إعادة توزيع الطاقة الاهتزازية داخل الجزيء (IVR) بطيئة جدًا لدرجة أن الجزيء يبدأ بالتفكك قبل أن تكتمل هذه الحالة شبه الحرارية، بما يتماشى مع تنبؤات سابقة قُدمت في إطار الميكانيكا الكلاسيكية حول السلوك غير الخاضع لنموذج RRKM.
|
ar
|
If any violation of Lorentz symmetry exists in the hadron sector, its ultimate origins must lie at the quark level. We continue the analysis of how the theories at these two levels are connected, using chiral perturbation theory. Considering a two-flavor quark theory, with dimension-4 operators that break Lorentz symmetry, we derive a low-energy theory of pions and nucleons that is invariant under local chiral transformations and includes the coupling to external fields. The pure meson and baryon sectors, as well as the couplings between them and the couplings to external electromagnetic and weak gauge fields, contain forms of Lorentz violation which depend on linear combinations of quark-level coefficients. In particular, at leading order the electromagnetic couplings depend on the very same combinations as appear in the free particle propagators. This means that observations of electromagnetic processes involving hadrons--such as vacuum Cerenkov radiation, which may be allowed in Lorentz-violating theories--can only reliably constrain certain particular combinations of quark coefficients.
|
Если в секторе адронов существует какое-либо нарушение симметрии Лоренца, его конечное происхождение должно лежать на уровне кварков. Мы продолжаем анализ связи между теориями на этих двух уровнях, используя теорию хиральных возмущений. Рассматривая двухфлейворную кварковую теорию с операторами размерности 4, нарушающими симметрию Лоренца, мы выводим теорию низких энергий для пионов и нуклонов, инвариантную относительно локальных хиральных преобразований и включающую связь со внешними полями. Секторы чистых мезонов и барионов, а также их взаимосвязи и связи со внешними электромагнитными и слабыми калибровочными полями содержат формы нарушения симметрии Лоренца, зависящие от линейных комбинаций коэффициентов на уровне кварков. В частности, на главном порядке электромагнитные связи зависят от тех же самых комбинаций, которые появляются в пропагаторах свободных частиц. Это означает, что наблюдения электромагнитных процессов с участием адронов — таких как вакуумное излучение Черенкова, которое может быть допустимо в теориях с нарушением симметрии Лоренца — могут надёжно ограничивать лишь определённые конкретные комбинации кварковых коэффициентов.
|
ru
|
Motion planning is an essential component in most of today's robotic applications. In this work, we consider the learning setting, where a set of solved motion planning problems is used to improve the efficiency of motion planning on different, yet similar problems. This setting is important in applications with rapidly changing environments such as in e-commerce, among others. We investigate a general deep learning based approach, where a neural network is trained to map an image of the domain, the current robot state, and a goal robot state to the next robot state in the plan. We focus on the learning algorithm, and compare supervised learning methods with reinforcement learning (RL) algorithms. We first establish that supervised learning approaches are inferior in their accuracy due to insufficient data on the boundary of the obstacles, an issue that RL methods mitigate by actively exploring the domain. We then propose a modification of the popular DDPG RL algorithm that is tailored to motion planning domains, by exploiting the known model in the problem and the set of solved plans in the data. We show that our algorithm, dubbed DDPG-MP, significantly improves the accuracy of the learned motion planning policy. Finally, we show that given enough training data, our method can plan significantly faster on novel domains than off-the-shelf sampling based motion planners. Results of our experiments are shown in https://youtu.be/wHQ4Y4mBRb8.
|
Plánování pohybu je klíčovou součástí většiny dnešních robotických aplikací. V této práci uvažujeme scénář učení, kdy je sada vyřešených problémů plánování pohybu využita k zlepšení efektivity plánování pohybu u jiných, avšak podobných problémů. Tento scénář je důležitý v aplikacích s rychle se měnícím prostředím, například v e-obchodu a dalších oblastech. Zkoumáme obecný přístup založený na hlubokém učení, kdy je neuronová síť trénována tak, aby z obrazu domény, aktuálního stavu robota a cílového stavu robota předpověděla další stav robota v plánu. Zaměřujeme se na algoritmus učení a porovnáváme metody učení s učitelem s algoritmy učení se posílením (RL). Nejprve ukazujeme, že metody učení s učitelem jsou v přesnosti horší kvůli nedostatečným datům na hranicích překážek, což je problém, který metody RL řeší aktivním zkoumáním domény. Poté navrhujeme modifikaci oblíbeného RL algoritmu DDPG, která je přizpůsobena doménám plánování pohybu využitím známého modelu problému a sady vyřešených plánů v datech. Ukazujeme, že náš algoritmus, který jsme označili jako DDPG-MP, výrazně zlepšuje přesnost naučené politiky plánování pohybu. Nakonec ukazujeme, že při dostatečném množství trénovacích dat dokáže naše metoda plánovat výrazně rychleji na nových doménách než standardní vzorkovací plánovače pohybu. Výsledky našich experimentů jsou zobrazeny na https://youtu.be/wHQ4Y4mBRb8.
|
cs
|
Supernova 1987A offers a unique opportunity to study an evolving supernova in unprecedented detail over several decades. The X-ray emission is dominated by interactions between the ejecta and the circumstellar medium, primarily the equatorial ring (ER). We analyze 3.3 Ms of NuSTAR data obtained between 2012 and 2020, and two decades of XMM-Newton data. Since ${\sim}$2013, the flux below 2 keV has declined, the 3-8 keV flux has increased, but has started to flatten, and the emission above 10 keV has remained nearly constant. The spectra are well described by a model with three thermal shock components. Two components at 0.3 and 0.9 keV are associated with dense clumps in the ER, and a 4 keV component may be a combination of emission from diffuse gas in the ER and the surrounding low-density H II region. We disfavor models that involve non-thermal X-ray emission and place constraints on non-thermal components, but cannot firmly exclude an underlying power law. Radioactive lines show a $^{44}$Ti redshift of $670^{+520}_{-380}$ km s$^{-1}$, $^{44}$Ti mass of $1.73_{-0.29}^{+0.27}\times{}10^{-4}$ solar masses, and $^{55}$Fe mass of $<4.2\times{}10^{-4}$ solar masses. The 35-65 keV luminosity limit on the compact object is $2\times{}10^{34}$ erg s$^{-1}$, and $<15$% of the 10-20 keV flux is pulsed. Considering previous limits, we conclude that there are currently no indications of a compact object, aside from a possible hint of dust heated by a neutron star in recent ALMA images.
|
সুপারনোভা 1987A একাধিক দশক ধরে অভূতপূর্ব বিস্তারিতভাবে একটি পরিবর্তনশীল সুপারনোভার অধ্যয়নের একটি অনন্য সুযোগ প্রদান করে। এক্স-রে নির্গমনটি মূলত নিক্ষিপ্ত পদার্থ এবং তার চারপাশের মাধ্যমের মধ্যে মিথস্ক্রিয়ার দ্বারা প্রভাবিত হয়, বিশেষ করে নাভিক বলয় (ER)। আমরা 2012 থেকে 2020 সালের মধ্যে প্রাপ্ত 3.3 মেগাসেকেন্ডের NuSTAR তথ্য এবং দুই দশকের XMM-নিউটন তথ্য বিশ্লেষণ করি। প্রায় 2013 সাল থেকে, 2 keV এর নিচের ফ্লাক্স কমেছে, 3-8 keV ফ্লাক্স বেড়েছে, কিন্তু এখন সমতল হওয়া শুরু করেছে, এবং 10 keV এর উপরের নির্গমন প্রায় স্থির রয়েছে। স্পেক্ট্রাগুলি তিনটি তাপীয় সংঘাত উপাদান সহ একটি মডেল দ্বারা ভালোভাবে বর্ণিত হয়। 0.3 এবং 0.9 keV এ দুটি উপাদান ER-এর ঘন গুচ্ছগুলির সাথে সম্পর্কিত, এবং 4 keV উপাদানটি ER-এর বিস্তৃত গ্যাস এবং চারপাশের কম ঘনত্বের H II অঞ্চল থেকে নির্গত নির্গমনের সমন্বয় হতে পারে। আমরা অ-তাপীয় এক্স-রে নির্গমন জড়িত মডেলগুলি পছন্দ করি না এবং অ-তাপীয় উপাদানগুলির উপর সীমাবদ্ধতা আরোপ করি, তবে একটি অন্তর্নিহিত পাওয়ার ল বাদ দিতে পারি না। তেজস্ক্রিয় রেখাগুলি $^{44}$Ti-এর 670$^{+520}_{-380}$ km s$^{-1}$ লোহিত সরণ, $^{44}$Ti-এর ভর 1.73$_{-0.29}^{+0.27}\times{}10^{-4}$ সৌর ভর এবং $^{55}$Fe-এর ভর <4.2$\times{}10^{-4}$ সৌর ভর দেখায়। কম্প্যাক্ট বস্তুর জন্য 35-65 keV আলোকমাত্রার সীমা হল 2$\times{}10^{34}$ erg s$^{-1}$, এবং 10-20 keV ফ্লাক্সের <15% পালস করা হয়। পূর্ববর্তী সীমাগুলি বিবেচনা করে, আমরা উপসংহারে আসি যে সদ্য ALMA ছবিগুলিতে নিউট্রন তারা দ্বারা উত্তপ্ত ধূলিকণার সম্ভাব্য ইঙ্গিত ছাড়া বর্তমানে কোনো কম্প্যাক্ট বস্তুর লক্ষণ নেই।
|
bn
|
We consider some crucial problems related to the secure and reliable operation of power systems with high renewable penetrations: how much reserve should we procure, how should reserve resources distribute among different locations, and how should we price reserve and charge uncertainty sources. These issues have so far been largely addressed empirically. In this paper, we first develop a scenario-oriented energy-reserve co-optimization model, which directly connects reserve procurement with possible outages and load/renewable power fluctuations without the need for empirical reserve requirements. Accordingly, reserve can be optimally procured system-wide to handle all possible future uncertainties with the minimum expected system total cost. Based on the proposed model, marginal pricing approaches are developed for energy and reserve, respectively. Locational uniform pricing is established for energy, and the similar property is also established for the combination of reserve and re-dispatch. In addition, properties of cost recovery for generators and revenue adequacy for the system operator are also proven.
|
Біз қайтымды энергияның жоғары деңгейде пайдаланылатын электр жүйелерінің қауіпсіз және сенімді жұмыс істеуіне байланысты кейбір маңызды мәселелерді қарастырамыз: біз қанша резерв алуымыз керек, резерв ресурстары әртүрлі орындарда қалай таралуы тиіс және резервке қанша ақы төлейміз және анықталмағандық көздеріне қанша ақы төлейміз. Бұл мәселелерге дейінгі уақытта негізінен эмпирикалық тұрғыдан жауап берілді. Бұл мақалада біз алдымен сценарийге бағытталған энергия-резерв бірлескен оптимизациялау моделін әзірлейміз, бұл модель эмпирикалық резерв талаптарына қажеттіліксіз резерв алу процесін мүмкін болатын сөндірулер мен жүктеме/қайтымды энергия қуатының тербелістерімен тікелей байланыстырады. Сәйкесінше, резерв барлық мүмкін болатын болашақтағы анықталмағандықтарды ең аз күтілетін жүйе жалпы құнымен есепке ала отырып, жүйенің бүкіл аумағында оптималды түрде алынуы мүмкін. Ұсынылған модельге негізделе отырып, энергия мен резерв үшін шектік баға белгілеу әдістері әзірленді. Энергия үшін орындық бірыңғай баға белгілеу енгізілді және резерв пен қайта жоспарлаудың үйлесімі үшін де осыған ұқсас қасиет орнатылды. Сонымен қатар, генераторлар үшін шығындарды қайтару мен жүйе операторы үшін табыстың жеткіліктілігі қасиеттері де дәлелденді.
|
kk
|
We present a study of analytic models of starless cores whose line profiles have ``infall asymmetry,'' or blue-skewed shapes indicative of contracting motions. We compare the ability of two types of analytical radiative transfer models to reproduce the line profiles and infall speeds of centrally condensed starless cores whose infall speeds are spatially constant and range between 0 and 0.2 km s-1. The model line profiles of HCO+ (J=1-0) and HCO+ (J=3-2) are produced by a self-consistent Monte Carlo radiative transfer code. The analytic models assume that the excitation temperature in the front of the cloud is either constant (``two-layer'' model) or increases inward as a linear function of optical depth (``hill'' model). Each analytic model is matched to the line profile by rapid least-squares fitting. The blue-asymmetric line profiles with two peaks, or with a blue shifted peak and a red shifted shoulder, can be well fit by the ``HILL5'' model (a five parameter version of the hill model), with an RMS error of 0.02 km s-1. A peak signal to noise ratio of at least 30 in the molecular line observations is required for performing these analytic radiative transfer fits to the line profiles.
|
Kami memaparkan sebuah kajian mengenai model analitik inti tanpa bintang yang memiliki profil garis dengan "asimetri jatuh ke dalam," atau bentuk miring ke biru yang mengindikasikan gerakan mengkerut. Kami membandingkan kemampuan dua jenis model transfer radiasi analitik untuk mereproduksi profil garis dan kecepatan jatuh ke dalam dari inti tanpa bintang yang terkondensasi di pusat, dengan kecepatan jatuh ke dalam yang konstan secara spasial dan berkisar antara 0 hingga 0,2 km s⁻¹. Profil garis model untuk HCO⁺ (J=1-0) dan HCO⁺ (J=3-2) dihasilkan oleh kode transfer radiasi Monte Carlo yang konsisten secara mandiri. Model analitik ini mengasumsikan bahwa suhu eksitasi di bagian depan awan bernilai konstan ("model dua lapisan") atau meningkat ke arah dalam sebagai fungsi linier dari kedalaman optik (model "bukit"). Setiap model analitik dicocokkan dengan profil garis melalui pencocokan kuadrat terkecil yang cepat. Profil garis asimetris ke biru dengan dua puncak, atau dengan puncak yang bergeser ke biru dan bahu yang bergeser ke merah, dapat dicocokkan dengan baik menggunakan model "HILL5" (versi model bukit dengan lima parameter), dengan kesalahan RMS sebesar 0,02 km s⁻¹. Rasio sinyal terhadap derau puncak minimal 30 pada pengamatan garis molekuler diperlukan untuk melakukan pencocokan transfer radiasi analitik terhadap profil garis tersebut.
|
id
|
Subspace models play an important role in a wide range of signal processing tasks, and this paper explores how the pairwise geometry of subspaces influences the probability of misclassification. When the mismatch between the signal and the model is vanishingly small, the probability of misclassification is determined by the product of the sines of the principal angles between subspaces. When the mismatch is more significant, the probability of misclassification is determined by the sum of the squares of the sines of the principal angles. Reliability of classification is derived in terms of the distribution of signal energy across principal vectors. Larger principal angles lead to smaller classification error, motivating a linear transform that optimizes principal angles. The transform presented here (TRAIT) preserves some specific characteristic of each individual class, and this approach is shown to be complementary to a previously developed transform (LRT) that enlarges inter-class distance while suppressing intra-class dispersion. Theoretical results are supported by demonstration of superior classification accuracy on synthetic and measured data even in the presence of significant model mismatch.
|
Кеңістіктің ішкі кеңістіктері моделі сигналды өңдеудің кең тарап кеткен міндеттерінде маңызды рөл атқарады және бұл мақалада ішкі кеңістіктердің жұптық геометриясы қате классификация ықтималдығына қалай әсер ететіні зерттеледі. Сигнал мен модель арасындағы сәйкессіздік өте аз болған кезде, қате классификация ықтималдығы ішкі кеңістіктер арасындағы бас бұрыштардың синустарының көбейтіндісі арқылы анықталады. Ал сәйкессіздік біраз көп болған кезде, қате классификация ықтималдығы бас бұрыштардың синустарының квадраттарының қосындысы арқылы анықталады. Классификация сенімділігі бас векторлар бойынша сигнал энергиясының таралуы тұрғысынан шығарылады. Үлкен бас бұрыштар классификация қатесін азайтады, сондықтан бас бұрыштарды оптималдауға мүмкіндік беретін сызықтық түрлендіру ұсынылады. Бұл жерде ұсынылған түрлендіру (TRAIT) әрбір жеке класстың кейбір нақты сипаттамаларын сақтайды және бұл тәсіл әлдеқашан әзірленген және кластар арасындағы қашықтықты ұлғайтатын, бірақ кластар ішіндегі шашырауды басып тұратын түрлендіруге (LRT) қосымша болып табылады. Теориялық нәтижелер синтетикалық және өлшенген деректерде, тіпті біраз көп модель сәйкессіздігі болған жағдайда да жоғарырақ классификация дәлдігін көрсету арқылы дәлелденеді.
|
kk
|
Enhanced diffusion of gold atoms into silicon substrate has been studied in Au thin films of various thicknesses (2.0, 5.3, 10.9 and 27.5 nm) deposited on Si(111) and followed by irradiation with 1.5 MeV Au2+ at a flux of 6.3x10^12 ions cm-2 s-1 and fluence up to 1x10^15 ions cm-2. The high resolution transmission electron microscopy measurements showed the presence of gold silicide formation for the above-mentioned systems at fluence greater than equal to 1x1014 ions cm-2. The maximum depth to which the gold atoms have been diffused at a fluence of 1x10^14 ions cm-2 for the cases of 2.0, 5.3, 10.9 and 27.5 nm thick films has been found to be 60, 95, 160 and 13 nm respectively. Interestingly, at higher fluence of 1x1015 ions cm-2 in case of 27.5 nm thick film, gold atoms from the film transported to a maximum depth of 265 nm in the substrate. The substrate silicon is found to be amorphous at the above fluence values where unusually large mass transport occurred. Enhanced diffusion has been explained on the basis of ion beam induced, flux dependent amorphous nature of the substrate, and transient beam induced temperature effects. This work confirms the absence of confinement effects that arise from spatially confined structures and existence of thermal and chemical reactions during ion irradiation.
|
Ang pinahusay na pagkalat ng mga atom ng ginto sa substrato ng silicon ay pinag-aralan sa mga manipis na pelikula ng Au na may iba't ibang kapal (2.0, 5.3, 10.9 at 27.5 nm) na inihulma sa Si(111) at sinusundan ng pagsusuyod gamit ang 1.5 MeV Au2+ sa isang daloy na 6.3x10^12 ions cm-2 s-1 at fluence hanggang 1x10^15 ions cm-2. Ang mga pagsukat gamit ang mataas na resolusyong transmisyon na mikroskopya ng electron ay nagpakita ng pagkakaroon ng pagsisilbi ng ginto na silicide para sa mga nabanggit na sistema sa fluence na higit sa o katumbas ng 1x10^14 ions cm-2. Ang pinakamataas na lalim kung saan napadalu ang mga atom ng ginto sa fluence na 1x10^14 ions cm-2 para sa mga pelikulang may kapal na 2.0, 5.3, 10.9 at 27.5 nm ay natagpuang 60, 95, 160 at 13 nm ayon sa pagkakabanggit. Kakaiba, sa mas mataas na fluence na 1x10^15 ions cm-2 sa kaso ng 27.5 nm kapal na pelikula, ang mga atom ng ginto mula sa pelikula ay nailipat sa pinakamalalim na 265 nm sa loob ng substrato. Natagpuang walang istrukturang kristal (amorphous) ang substratong silicon sa mga nabanggit na halaga ng fluence kung saan naganap ang hindi kadalasang malaking paglilipat ng masa. Ang pinahusay na pagkalat ay ipinaliwanag batay sa ion beam-induced, daloy-dependent na amorphous na kalikasan ng substrato, at sa pansamantalang beam-induced na epekto ng temperatura. Ang gawaing ito ay nagpapatibay sa kawalan ng mga epekto ng pagkakapiit na nagmumula sa spatially confined na mga istruktura at sa pag-iral ng thermal at kemikal na reaksyon habang nagaganap ang ion irradiation.
|
tl
|
In this work, we propose to utilize discrete graph Ricci flow to alter network entropy through feedback control. Given such feedback input can reverse entropic changes, we adapt the moniker of Maxwells Demon to motivate our approach. In particular, it has been recently shown that Ricci curvature from geometry is intrinsically connected to Boltzmann entropy as well as functional robustness of networks or the ability to maintain functionality in the presence of random fluctuations. From this, the discrete Ricci flow provides a natural avenue to rewire a particular networks underlying geometry to improve throughout and resilience. Due to the real-world setting for which one may be interested in imposing nonlinear constraints amongst particular agents to understand the network dynamic evolution, controlling discrete Ricci flow may be necessary (e.g., we may seek to understand the entropic dynamics and curvature flow between two networks as opposed to solely curvature shrinkage). In turn, this can be formulated as a natural control problem for which we employ feedback control towards discrete Ricci-based flow and show that under certain discretization, namely Ollivier-Ricci curvature, one can show stability via Lyapunov analysis. We conclude with preliminary results with remarks on potential applications that will be a subject of future work.
|
Neste trabalho, propomos utilizar o fluxo de Ricci discreto em grafos para alterar a entropia da rede por meio de controle por realimentação. Dado que essa entrada de realimentação pode reverter mudanças entrópicas, adaptamos o apelido do Demônio de Maxwell para motivar nossa abordagem. Em particular, foi recentemente demonstrado que a curvatura de Ricci proveniente da geometria está intrinsecamente ligada à entropia de Boltzmann, bem como à robustez funcional de redes, ou seja, à capacidade de manter a funcionalidade na presença de flutuações aleatórias. A partir disso, o fluxo de Ricci discreto fornece uma via natural para reconectar a geometria subjacente de uma rede particular, a fim de melhorar sua capacidade de throughput e resiliência. Devido ao contexto do mundo real no qual se pode estar interessado em impor restrições não lineares entre agentes específicos para compreender a evolução dinâmica da rede, o controle do fluxo de Ricci discreto pode ser necessário (por exemplo, pode-se buscar compreender a dinâmica entrópica e o fluxo de curvatura entre duas redes, em vez de apenas a contração da curvatura). Por sua vez, isso pode ser formulado como um problema de controle natural, para o qual empregamos controle por realimentação voltado ao fluxo baseado em Ricci discreto, mostrando que, sob certa discretização, nomeadamente a curvatura de Ollivier-Ricci, é possível demonstrar estabilidade por meio de análise de Lyapunov. Concluímos com resultados preliminares e observações sobre possíveis aplicações, que serão objeto de trabalhos futuros.
|
pt
|
Poisson Voronoi tessellations have been used in modeling many types of systems across different sciences, from geography and astronomy to telecommunications. The existing literature on the statistical properties of Poisson Voronoi cells is vast, however, little is known about the properties of Voronoi cells located close to the boundaries of a compact domain. In a domain with boundaries, some Voronoi cells would be naturally clipped by the boundary, and the cell area falling inside the deployment domain would have different statistical properties as compared to those of non-clipped Voronoi cells located in the bulk of the domain. In this paper, we consider the planar Voronoi tessellation induced by a homogeneous Poisson point process of intensity $\lambda\!>\!0$ in a quadrant, where the two half-axes represent boundaries. We show that the mean cell area is less than $\lambda^{-1}$ when the seed is located exactly at the boundary, and it can be larger than $\lambda^{-1}$ when the seed lies close to the boundary. In addition, we calculate the second moment of cell area at two locations for the seed: (i) at the corner of a quadrant, and (ii) at the boundary of the half-plane. We illustrate that the two-parameter Gamma distribution, with location-dependent parameters calculated using the method of moments, can be of use in approximating the distribution of cell area. As a potential application, we use the Gamma approximations to study the degree distribution for secure connectivity in wireless sensor networks deployed over a domain with boundaries.
|
ການຈັດຮູບພາບໂວໂລໄນ (Voronoi) ຂອງໂປອິດຊັງ (Poisson) ໄດ້ຖືກນຳໃຊ້ໃນການສ້າງຮູບແບບຂອງລະບົບຕ່າງໆ ໃນຂົງເຂດວິທະຍາສາດທີ່ແຕກຕ່າງກັນ ເຊັ່ນ: ພູມິສາດ, ດາລາສາດ ແລະ ການສື່ສານ. ມີບົດຄວາມວິຊາການຈຳນວນຫຼວງຫຼາຍກ່ຽວກັບຄຸນສົມບັດທາງສະຖິຕິຂອງເຊວໂວໂລໄນ (Voronoi cells) ຂອງໂປອິດຊັງ, ແຕ່ກໍຍັງມີຄວາມຮູ້ໜ້ອຍກ່ຽວກັບຄຸນສົມບັດຂອງເຊວໂວໂລໄນທີ່ຕັ້ງຢູ່ໃກ້ກັບເສັ້ນຊາຍແດນຂອງເຂດທີ່ມີຂອບເຂດຈຳກັດ. ໃນເຂດທີ່ມີເສັ້ນຊາຍແດນ, ເຊວໂວໂລໄນບາງອັນຈະຖືກຕັດສັ້ນໂດຍເສັ້ນຊາຍແດນໂດຍທຳມະຊາດ, ແລະ ເນື້ອທີ່ຂອງເຊວທີ່ຢູ່ພາຍໃນເຂດຈະມີຄຸນສົມບັດທາງສະຖິຕິທີ່ແຕກຕ່າງຈາກເຊວໂວໂລໄນທີ່ບໍ່ຖືກຕັດ ແລະ ຕັ້ງຢູ່ໃນສ່ວນກາງຂອງເຂດ. ໃນບົດຄວາມນີ້, ພວກເຮົາພິຈາລະນາການຈັດຮູບພາບໂວໂລໄນໃນແບບສອງມິຕິ ທີ່ຖືກສ້າງຂຶ້ນໂດຍຂະບວນການຈຸດໂປອິດຊັງທີ່ເປັນເອກະພາບ ທີ່ມີຄວາມເຂັ້ມຂົ້ນ $\lambda\!>\!0$ ໃນເຂດຈະກອງ, ໂດຍທີ່ແກນເຄິ່ງທັງສອງແຖວເປັນຕົວແທນໃຫ້ກັບເສັ້ນຊາຍແດນ. ພວກເຮົາສະແດງໃຫ້ເຫັນວ່າ ເນື້ອທີ່ສະເລ່ຍຂອງເຊວຈະນ້ອຍກວ່າ $\lambda^{-1}$ ເມື່ອຈຸດກາງ (seed) ຕັ້ງຢູ່ທີ່ເສັ້ນຊາຍແດນຢ່າງແທ້ຈິງ, ແລະ ມັນອາດຈະໃຫຍ່ກວ່າ $\lambda^{-1}$ ເມື່ອຈຸດກາງຕັ້ງຢູ່ໃກ້ກັບເສັ້ນຊາຍແດນ. ນອກຈາກນັ້ນ, ພວກເຮົາຍັງຄຳນວນຄ່າຂອງອະນຸພາກທີສອງ (second moment) ຂອງເນື້ອທີ່ເຊວໃນສອງຕຳແໜ່ງຂອງຈຸດກາງ: (i) ທີ່ມຸມຂອງເຂດຈະກອງ, ແລະ (ii) ທີ່ເສັ້ນຊາຍແດນຂອງເຂດເຄິ່ງແຜ່ນດິນ. ພວກເຮົາສະແດງໃຫ້ເຫັນວ່າ ການແຈກຢາຍກາມມາ (Gamma distribution) ທີ່ມີສອງພາລາມິເຕີ, ໂດຍທີ່ພາລາມິເຕີຂຶ້ນກັບຕຳແໜ່ງ ແລະ ຖືກຄຳນວນໂດຍໃຊ້ວິທີຂອງອະນຸພາກ (method of moments), ສາມາດນຳໃຊ້ເພື່ອປະມານການແຈກຢາຍຂອງເນື້ອທີ່ເຊວ. ເປັນການນຳໃຊ້ທີ່ເປັນໄປໄດ້, ພວກເຮົາໃຊ້ການປະມານກາມມາເພື່ອສຶກສາການແຈກຢາຍຂອງກະແສ (degree distribution) ສຳລັບການເຊື່ອມຕໍ່ທີ່ປອດໄພໃນເຄືອຂ່າຍເຊັນເຊີບໍລວມທີ່ຖືກຕິດຕັ້ງໃນເຂດທີ່ມີເສັ້ນຊາຍແດນ.
|
lo
|
The relationship between variability, luminosity and redshift in the South Galactic Pole QSO sample is examined in an effort to disentangle the effects of luminosity and redshift in the amplitude of the optical variations. The anticorrelation between variability and luminosity found by other authors is confirmed. Our analysis also supports claims that variability increases with redshift, most likely due to an anticorrelation between variability and wavelength. In particular, our parametric fits show that the QSO variability-wavelength relation is consistent with that observed in low-luminosity nearby active galactic nuclei. The results are used to constrain Poissonian-type models. We find that if QSO variability results from a random superposition of pulses, then the individual events must have B-band energies between $\sim 10^{50}$ and a few times $10^{51}$ erg and time-scales of $\sim 2$ yr. Generalized Poissonian models in which the pulse energy and lifetime scale with luminosity are also discussed.
|
Ang ugnayan sa pagitan ng pagbabago, kaliwanagan, at redshift sa sample ng QSO sa South Galactic Pole ay sinuri upang paghiwalayin ang epekto ng kaliwanagan at redshift sa antas ng mga pagbabago sa optical. Tinatanggap ang negatibong ugnayan sa pagitan ng pagbabago at kaliwanagan na natuklasan ng iba pang mga may-akda. Sumusuporta rin ang aming pagsusuri sa mga panawagan na tumataas ang pagbabago kasama ang redshift, na marahil ay dahil sa negatibong ugnayan sa pagitan ng pagbabago at haba ng alon. Partikular, ipinapakita ng aming parametric fits na ang ugnayan ng QSO variability-wavelength ay tugma sa obserbasyon sa mga malapit na aktibong galactic nuclei na may mababang kaliwanagan. Ginamit ang mga resulta upang limitahan ang mga modelo na katulad ng Poissonian. Natagpuan namin na kung ang pagbabago ng QSO ay nagmumula sa random na pagsusunod-sunod ng mga pulso, ang bawat pangyayari ay dapat magkaroon ng B-band na enerhiya sa pagitan ng ∼10⁵⁰ at ilang beses na 10⁵¹ erg at mga oras na may sukat na ∼2 taon. Tinatalakay din ang mga pangkalahatang modelo ng Poissonian kung saan ang enerhiya at tagal ng pulso ay nakasakop sa kaliwanagan.
|
tl
|
A simple one-dimensional model for SNS weak links in the ballistic limit is presented. In the presence of a bias voltage, the quasiparticle state at any given instant of time is described as a superposition of that particular set of phase-dependent Andreev bound states that belongs to the specific phase difference present at this instant between the superconducting banks. The treatment -- basically a form of adiabatic perturbation theory -- has a strong formal similarity to the treatment of the k-space dynamics of an electron in a periodic potential under perturbation by an external electric field, sufficiently strong to cause transitions across the energy gaps between bands (Zener tunneling). It is shown that the quasiparticle wave function retains its phase information during analogous transitions between Andreev bands. The experimental observation of Shapiro steps at one-half the canonical voltage follows naturally from the model, along with some of the experimental properties of these steps, especially their much weaker temperature dependence, compared to the canonical steps.
|
ব্যালিস্টিক সীমার মধ্যে SNS দুর্বল সংযোগগুলির জন্য একটি সরল এক-মাত্রিক মডেল উপস্থাপন করা হয়েছে। একটি বায়াস ভোল্টেজ উপস্থিত থাকলে, কোনো নির্দিষ্ট সময়ে কোয়াসিপার্টিকেল অবস্থাকে সুপারকন্ডাক্টিং ব্যাঙ্কগুলির মধ্যে এই মুহূর্তে উপস্থিত নির্দিষ্ট ফেজ পার্থক্যের সাথে সম্পর্কিত ফেজ-নির্ভর অ্যান্ড্রিউ বাউন্ড স্টেটগুলির একটি নির্দিষ্ট সেটের উপরিপাতন হিসাবে বর্ণনা করা হয়। এই চিকিৎসা—মূলত এক ধরনের অ্যাডিয়াবেটিক বিক্ষোভ তত্ত্ব—বাহ্যিক তড়িৎ ক্ষেত্র দ্বারা বিক্ষুব্ধ হওয়া একটি পর্যায়বৃত্ত সম্ভাব্যতার মধ্যে একটি ইলেকট্রনের k-স্পেস গতিবিদ্যার চিকিৎসার সাথে শক্তিশালী আনুষ্ঠানিক সাদৃশ্য রাখে, যা ব্যান্ডগুলির মধ্যে শক্তির ফাঁকগুলির মধ্য দিয়ে সংক্রমণ ঘটানোর জন্য যথেষ্ট শক্তিশালী (জেনার টানেলিং)। দেখানো হয়েছে যে অ্যান্ড্রিউ ব্যান্ডগুলির মধ্যে এই ধরনের সংক্রমণের সময় কোয়াসিপার্টিকেল তরঙ্গ ফাংশন তার ফেজ তথ্য ধরে রাখে। ক্যাননিকাল ভোল্টেজের ঠিক অর্ধেক ভোল্টেজে শ্যাপিরো ধাপগুলির পরীক্ষামূলক পর্যবেক্ষণ মডেল থেকে স্বাভাবিকভাবেই অনুসরণ করে, এই ধাপগুলির কিছু পরীক্ষামূলক বৈশিষ্ট্যসহ, বিশেষ করে ক্যাননিকাল ধাপগুলির তুলনায় তাদের অনেক দুর্বল তাপমাত্রা নির্ভরশীলতা।
|
bn
|
We present a study of analytic models of starless cores whose line profiles have ``infall asymmetry,'' or blue-skewed shapes indicative of contracting motions. We compare the ability of two types of analytical radiative transfer models to reproduce the line profiles and infall speeds of centrally condensed starless cores whose infall speeds are spatially constant and range between 0 and 0.2 km s-1. The model line profiles of HCO+ (J=1-0) and HCO+ (J=3-2) are produced by a self-consistent Monte Carlo radiative transfer code. The analytic models assume that the excitation temperature in the front of the cloud is either constant (``two-layer'' model) or increases inward as a linear function of optical depth (``hill'' model). Each analytic model is matched to the line profile by rapid least-squares fitting. The blue-asymmetric line profiles with two peaks, or with a blue shifted peak and a red shifted shoulder, can be well fit by the ``HILL5'' model (a five parameter version of the hill model), with an RMS error of 0.02 km s-1. A peak signal to noise ratio of at least 30 in the molecular line observations is required for performing these analytic radiative transfer fits to the line profiles.
|
Nous présentons une étude de modèles analytiques de cœurs sans étoile dont les profils de raies présentent une « asymétrie d'effondrement », ou des formes penchées vers le bleu, indicatives de mouvements de contraction. Nous comparons la capacité de deux types de modèles analytiques de transfert radiatif à reproduire les profils de raies et les vitesses d'effondrement de cœurs sans étoile à condensation centrale dont les vitesses d'effondrement sont spatialement constantes et varient entre 0 et 0,2 km s⁻¹. Les profils de raies modélisés pour HCO⁺ (J=1-0) et HCO⁺ (J=3-2) sont produits par un code auto-cohérent de transfert radiatif de type Monte Carlo. Les modèles analytiques supposent que la température d'excitation à l'avant du nuage est soit constante (modèle « à deux couches »), soit augmente vers l'intérieur selon une fonction linéaire de la profondeur optique (modèle « en colline »). Chaque modèle analytique est ajusté au profil de raie par une méthode rapide des moindres carrés. Les profils de raies asymétriques vers le bleu, présentant deux pics, ou un pic décalé vers le bleu et une bosse décalée vers le rouge, peuvent être bien ajustés par le modèle « HILL5 » (une version à cinq paramètres du modèle en colline), avec une erreur RMS de 0,02 km s⁻¹. Un rapport signal sur bruit au pic d'au moins 30 dans les observations des raies moléculaires est nécessaire pour réaliser ces ajustements analytiques de transfert radiatif aux profils de raies.
|
fr
|
The dynamical response of an Ising ferromagnet to a plane polarised standing magnetic field wave is modelled and studied here by Monte Carlo simulation in two dimensions. The amplitude of standing magnetic wave is modulated along the direction x. We have detected two main dynamical phases namely, pinned and oscillating spin clusters. Depending on the value of field amplitude the system is found to undergo a phase transition from oscillating spin cluster to pinned as the system is cooled down. The time averaged magnetisation over a full cycle of magnetic field oscillations is defined as the dynamic order parameter. The transition is detected by studying the temperature dependences of the variance of the dynamic order parameter, the derivative of the dynamic order parameter and the dynamic specific heat. The dependence of the transition temperature on the magnetic field amplitude and on the wavelength of the magnetic field wave is studied at a single frequency. A comprehensive phase boundary is drawn in the plane described by the temperature and field amplitude for two different wavelengths of the magnetic wave. The variation of instantaneous line magnetisation during a period of magnetic field oscillation for standing wave mode is compared to those for the propagating wave mode. Also the probability that a spin at any site, flips, is calculated. The above mentioned variations and the probability of spin flip clearly distinguish between the dynamical phases formed by propagating magnetic wave and by standing magnetic wave in an Ising ferromagnet.
|
Dynamická odezva Isingova feromagnetu na rovinnou polarizovanou stojatou magnetickou vlnu je zde modelována a studována metodou Monte Carlo ve dvou rozměrech. Amplituda stojaté magnetické vlny je modulována ve směru x. Detekovali jsme dvě hlavní dynamické fáze, a to připevněné a oscilující shluky spinů. V závislosti na hodnotě amplitudy pole bylo zjištěno, že systém při ochlazování prochází fázovým přechodem z oscilujících shluků spinů do připevněných. Časově průměrovaná magnetizace přes jednu plnou periodu oscilací magnetického pole je definována jako dynamický parametr pořádku. Přechod je detekován prostřednictvím studia teplotní závislosti variance dynamického parametru pořádku, derivace dynamického parametru pořádku a dynamické měrné tepelné kapacity. Závislost přechodové teploty na amplitudě magnetického pole a na vlnové délce magnetické vlny je studována při jediné frekvenci. Pro dvě různé vlnové délky magnetické vlny je sestrojena komplexní fázová hranice v rovině popsané teplotou a amplitudou pole. Variace okamžité čárové magnetizace během jedné periody oscilací magnetického pole pro režim stojaté vlny je porovnána s případem postupné vlny. Dále je vypočtena pravděpodobnost, že se spin na libovolném místě přepne. Výše uvedené variace a pravděpodobnost překlopení spinu jasně rozlišují mezi dynamickými fázemi vytvořenými postupnou magnetickou vlnou a stojatou magnetickou vlnou v Isingově feromagnetu.
|
cs
|
The Doppler dipole signal dominates the cosmic microwave background (CMB) anisotropy maps obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) mission, and plays a key role throughout the data processing. Previously, we discovered a timing asynchronism of -25.6ms between the timestamps of the spacecraft attitude and radiometer output in the original raw WMAP time-ordered data (TOD), which, if not corrected in following data processing, would generate an artificial quadrupole component (l=2) in recovered CMB maps (Liu, Xiong & Li 2010). Recently, Roukema (2010b) proves that there does exist a timing-offset-induced error corresponding to about -25.6ms in the WMAP calibrated TOD by studying the fluctuation variance per pixel in the temperature map recovered from the TOD as a function of assumed timing-offset. Here, we find evidence directly in the WMAP TOD for such an uncorrected timing error, possibly occurred in calculating the Doppler dipole signal during the WMAP team's TOD data processing. The amplitude is highly significant and is consistent with previous work. We also show that the uncorrected timing-offset can lead the WMAP CMB quadrupole to be substantially overestimated.
|
Il segnale Doppler dipolare domina le mappe dell'anisotropia della radiazione cosmica di fondo a microonde (CMB) ottenute dalla missione Wilkinson Microwave Anisotropy Probe (WMAP) e svolge un ruolo chiave in tutto il processo di elaborazione dei dati. In precedenza, abbiamo scoperto un'asincronia temporale di -25,6 ms tra i timestamp dell'assetto del veicolo spaziale e l'uscita del radiometro nei dati originali grezzi di WMAP (TOD), la quale, se non corretta nell'elaborazione successiva dei dati, genererebbe una componente quadrupolare artificiale (l=2) nelle mappe CMB ricostruite (Liu, Xiong & Li 2010). Recentemente, Roukema (2010b) ha dimostrato che esiste effettivamente un errore indotto da uno scostamento temporale corrispondente a circa -25,6 ms nei dati TOD calibrati di WMAP, analizzando la varianza delle fluttuazioni per pixel nella mappa di temperatura ricostruita dai dati TOD in funzione dello scostamento temporale ipotizzato. Qui, troviamo evidenza diretta nei dati TOD di WMAP di tale errore temporale non corretto, verificatosi probabilmente nel calcolo del segnale Doppler dipolare durante l'elaborazione dei dati TOD da parte del team di WMAP. L'ampiezza è altamente significativa ed è coerente con i risultati precedenti. Mostriamo inoltre che lo scostamento temporale non corretto può portare a un sovrastima sostanziale del quadrupolo CMB di WMAP.
|
it
|
We prove Abelian magnetic monopole dominance in the string tension of QCD. Abelian and monopole dominance in low energy physics of QCD has been confirmed for various quantities by recent Monte Carlo simulations of lattice gauge theory. In order to prove this dominance, we use the reformulation of continuum Yang-Mills theory in the maximal Abelian gauge as a deformation of a topological field theory of magnetic monopoles, which was proposed in the previous article by the author. This reformulation provides an efficient way for incorporating the magnetic monopole configuration as a topological non-trivial configuration in the functional integral. We derive a version of the non-Abelian Stokes theorem and use it to estimate the expectation value of the Wilson loop. This clearly exhibits the role played by the magnetic monopole as an origin of the Berry phase in the calculation of the Wilson loop in the manifestly gauge invariant manner. We show that the string tension derived from the diagonal (abelian) Wilson loop in the topological field theory (studied in the previous article) converges to that of the full non-Abelian Wilson loop in the limit of large Wilson loop. Therefore, within the above reformulation of QCD, this result (together with the previous result) completes the proof of quark confinement in QCD based on the criterion of the area law of the full non-Abelian Wilson loop.
|
ہم کیو سی ڈی کی سٹرنگ تناؤ میں ایبلین میگنیٹک مونوپول کی بالادستی کو ثابت کرتے ہیں۔ کیو سی ڈی کی کم توانائی فزکس میں ایبلین اور مونوپول کی بالادستی کی تصدیق حالیہ مونٹی کارلو سیمیولیشنز کے ذریعے لیٹس گیج تھیوری کی مختلف کمیتوں کے لیے کی گئی ہے۔ اس بالادستی کو ثابت کرنے کے لیے، ہم مکسویمل ایبلین گیج میں کنٹینیم یانگ-ملز تھیوری کی دوبارہ تشکیل کا استعمال کرتے ہیں جو میگنیٹک مونوپولز کی ٹوپولوجیکل فیلڈ تھیوری کی تبدیلی کی صورت میں ہے، جو مصنف کے پچھلے مضمون میں تجویز کی گئی تھی۔ یہ دوبارہ تشکیل فنکشنل انٹیگرل میں ٹوپولوجیکلی غیر معمولی کنفیگریشن کے طور پر میگنیٹک مونوپول کنفیگریشن کو شامل کرنے کا ایک مؤثر طریقہ فراہم کرتی ہے۔ ہم غیر ایبلین اسٹوکس تھیورم کا ایک ورژن وضع کرتے ہیں اور اس کا استعمال وِلسن لوپ کی توقع کی قیمت کا اندازہ لگانے کے لیے کرتے ہیں۔ یہ وِلسن لوپ کے حساب کتاب میں بیری فیز کے ماخذ کے طور پر میگنیٹک مونوپول کے کردار کو واضح طور پر ظاہر کرتا ہے، جو مکمل طور پر گیج ان ویریئنٹ انداز میں ہوتا ہے۔ ہم دکھاتے ہیں کہ ٹوپولوجیکل فیلڈ تھیوری میں قُطْبی (ایبلین) وِلسن لوپ سے حاصل کردہ سٹرنگ تناؤ بڑے وِلسن لوپ کی حد میں مکمل غیر ایبلین وِلسن لوپ کے سٹرنگ تناؤ کی طرف رجحان رکھتا ہے۔ اس لیے، کیو سی ڈی کی مذکورہ بالا دوبارہ تشکیل کے اندر، یہ نتیجہ (پچھلے نتیجے کے ساتھ مل کر) مکمل غیر ایبلین وِلسن لوپ کے ایریا لا کے معیار پر مبنی کیو سی ڈی میں کوارک کنفائنمنٹ کی ثبوت کو مکمل کرتا ہے۔
|
ur
|
The routing and wavelength assignment with protection is an important problem in telecommunications. Given an optical network and incoming connection requests, a commonly studied variant of the problem aims to grant maximum number of requests by assigning lightpaths at minimum network resource usage level, while ensuring the provided services remain functional in case of a single-link failure through dedicated path protection. We consider a practically relevant version where alternative lightpaths for requests are assumed to be given as a precomputed set, and show that it is NP-hard. We formulate the problem as an integer programming (IP) model, and also use it as a foundation to develop a novel quadratic unconstrained binary optimization (QUBO) model, which can be both directly solved by a state-of-the-art solver like GUROBI. We present necessary and sufficient conditions on objective function parameters to prioritize request granting objective over wavelength-link usage for both models, and a sufficient condition to ensure the exactness of the QUBO model. Moreover, we implement a problem-specific branch-and-cut algorithm for the IP model, and employ a new quantum-inspired technology, Digital Annealer (DA), for the QUBO model. We conduct computational experiments on a large suite of instances that are hard to optimally solve in order to assess the efficiency and efficacy of all of these approaches as well as a problem-specific heuristic. The results show that the emerging technology DA outperforms the considered established techniques coupled with GUROBI, in finding mostly significantly better or as good solutions in only two minutes compared to two hours of run time, whereas the problem-specific heuristic fails to be competitive.
|
Penugasan rute dan panjang gelombang dengan perlindungan merupakan masalah penting dalam telekomunikasi. Diberikan sebuah jaringan optik dan permintaan koneksi yang masuk, salah satu varian masalah yang banyak diteliti bertujuan untuk memenuhi sebanyak mungkin permintaan dengan menetapkan lightpath pada tingkat penggunaan sumber daya jaringan seminimal mungkin, sekaligus memastikan layanan yang disediakan tetap berfungsi dalam kondisi terjadi kegagalan satu-sambungan melalui perlindungan jalur khusus (dedicated path protection). Kami mempertimbangkan versi yang relevan secara praktis, di mana lightpath alternatif untuk permintaan dianggap telah diberikan sebagai himpunan yang telah diperhitungkan sebelumnya, dan menunjukkan bahwa versi ini termasuk NP-hard. Kami merumuskan masalah ini sebagai model pemrograman bulat (integer programming/IP), serta menggunakan model tersebut sebagai dasar untuk mengembangkan model optimasi biner tanpa batasan kuadratik (quadratic unconstrained binary optimization/QUBO) yang baru, yang dapat langsung diselesaikan oleh solver mutakhir seperti GUROBI. Kami menyajikan kondisi perlu dan cukup terhadap parameter fungsi objektif untuk memprioritaskan tujuan pemenuhan permintaan dibandingkan penggunaan panjang gelombang-tautan pada kedua model, serta kondisi cukup untuk menjamin keakuratan model QUBO. Selain itu, kami mengimplementasikan algoritma cabang-dan-potong (branch-and-cut) khusus masalah untuk model IP, serta menggunakan teknologi inspirasi kuantum yang baru, Digital Annealer (DA), untuk model QUBO. Kami melakukan eksperimen komputasi pada sejumlah besar instans yang sulit diselesaikan secara optimal guna menilai efisiensi dan efektivitas semua pendekatan ini, serta sebuah heuristik khusus masalah. Hasil menunjukkan bahwa teknologi yang sedang berkembang, DA, melampaui teknik-teknik mapan yang dipasangkan dengan GUROBI, dengan menemukan solusi yang umumnya jauh lebih baik atau setara dalam waktu hanya dua menit dibandingkan dua jam waktu eksekusi, sementara heuristik khusus masalah gagal bersaing.
|
id
|
High-quality long-distance entanglement is essential for both quantum communication and scalable quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it plays a key role in quantum repeaters. The previous significant entanglement purification experiments require two pairs of low-quality entangled states and were demonstrated in table-top. Here we propose and report a high-efficiency and long-distance entanglement purification using only one pair of hyperentangled states. We also demonstrate its practical application in entanglement-based quantum key distribution (QKD). One pair of polarization spatial-mode hyperentanglement was distributed over 11 km multicore fiber (noisy channel). After purification, the fidelity of polarization entanglement arises from 0.771 to 0.887 and the effective key rate in entanglement-based QKD increases from 0 to 0.332. The values of Clauser-Horne-Shimony-Holt (CHSH) inequality of polarization entanglement arises from 1.829 to 2.128. Moreover, by using one pair of hyperentanglement and deterministic controlled-NOT gate, the total purification efficiency can be estimated as 6.6x10^3 times than the experiment using two pairs of entangled states with spontaneous parametric down-conversion (SPDC) sources. Our results offer the potential to be implemented as part of a full quantum repeater and large scale quantum network.
|
高质量的长距离纠缠对于量子通信和可扩展的量子网络都至关重要。纠缠纯化是指在噪声环境中从低质量纠缠态中提纯出高质量纠缠态，它在量子中继器中起着关键作用。以往重要的纠缠纯化实验需要两对低质量纠缠态，且仅在桌面系统中实现。本文中，我们提出并实现了一种仅使用一对超纠缠态的高效率、长距离纠缠纯化方案，并展示了其在基于纠缠的量子密钥分发（QKD）中的实际应用。一对偏振-空间模式超纠缠态被分发到11公里长的多芯光纤（噪声信道）中。经过纯化后，偏振纠缠的保真度从0.771提升至0.887，基于纠缠的QKD的有效密钥率从0提升至0.332。偏振纠缠的Clauser-Horne-Shimony-Holt（CHSH）不等式值从1.829提升至2.128。此外，通过使用一对超纠缠态和确定性的受控非门，总纯化效率估计可达到使用两对纠缠态和自发参量下转换（SPDC）光源实验的6.6×10³倍。我们的结果为实现完整的量子中继器和大规模量子网络提供了潜在的技术路径。
|
zh
|
Following Riley's work, for each 2-bridge link $K(r)$ of slope $r\in\QQ$ and an integer or a half-integer $n$ greater than 1, we introduce the {\it Heckoid orbifold $\orbs(r;n)$} and the {\it Heckoid group $\Hecke(r;n)=\pi_1(\orbs(r;n))$ of index $n$ for $K(r)$}. When $n$ is an integer, $\orbs(r;n)$ is called an {\it even} Heckoid orbifold; in this case, the underlying space is the exterior of $K(r)$, and the singular set is the lower tunnel of $K(r)$ with index $n$. The main purpose of this note is to announce answers to the following questions for even Heckoid orbifolds. (1) For an essential simple loop on a 4-punctured sphere $\PConway$ in $\orbs(r;n)$ determined by the 2-bridge sphere of $K(r)$, when is it null-homotopic in $\orbs(r;n)$? (2) For two distinct essential simple loops on $\PConway$, when are they homotopic in $\orbs(r;n)$? We also announce applications of these results to character varieties, McShane's identity, and epimorphisms from 2-bridge link groups onto Heckoid groups.
|
Sunod sa gawa ni Riley, para sa bawat 2-tulay na link $K(r)$ na may lihis na $r\in\QQ$ at isang buong bilang o kalahating buong bilang na $n$ na mas malaki kaysa 1, ipinakikilala namin ang {\it orbifold na Heckoid $\orbs(r;n)$} at ang {\it grupong Heckoid $\Hecke(r;n)=\pi_1(\orbs(r;n))$ na may indeks na $n$ para sa $K(r)$}. Kapag ang $n$ ay isang buong bilang, ang $\orbs(r;n)$ ay tinatawag na {\it even} (panghaba) na orbifold na Heckoid; sa kasong ito, ang pangunahing espasyo ay ang panlabas ng $K(r)$, at ang singular na set ay ang mas mababang tunel ng $K(r)$ na may indeks na $n$. Ang pangunahing layunin ng tala na ito ay ipahayag ang mga sagot sa mga sumusunod na tanong para sa mga even na orbifold na Heckoid. (1) Para sa isang mahalagang simpleng loop sa isang 4-pinauhaw na esferang $\PConway$ sa $\orbs(r;n)$ na natutukoy ng 2-tulay na esfera ng $K(r)$, kailan ito null-homotopiko sa $\orbs(r;n)$? (2) Para sa dalawang magkaibang mahahalagang simpleng loop sa $\PConway$, kailan sila homotopiko sa $\orbs(r;n)$? Ipinahahayag din namin ang mga aplikasyon ng mga resultang ito sa mga character variety, sa identidad ni McShane, at sa mga epimorphism mula sa mga grupong 2-tulay na link patungo sa mga grupong Heckoid.
|
tl
|
The Doppler dipole signal dominates the cosmic microwave background (CMB) anisotropy maps obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) mission, and plays a key role throughout the data processing. Previously, we discovered a timing asynchronism of -25.6ms between the timestamps of the spacecraft attitude and radiometer output in the original raw WMAP time-ordered data (TOD), which, if not corrected in following data processing, would generate an artificial quadrupole component (l=2) in recovered CMB maps (Liu, Xiong & Li 2010). Recently, Roukema (2010b) proves that there does exist a timing-offset-induced error corresponding to about -25.6ms in the WMAP calibrated TOD by studying the fluctuation variance per pixel in the temperature map recovered from the TOD as a function of assumed timing-offset. Here, we find evidence directly in the WMAP TOD for such an uncorrected timing error, possibly occurred in calculating the Doppler dipole signal during the WMAP team's TOD data processing. The amplitude is highly significant and is consistent with previous work. We also show that the uncorrected timing-offset can lead the WMAP CMB quadrupole to be substantially overestimated.
|
Sinyal dipol Doppler mendominasi peta anisotropi latar belakang gelombang mikro kosmik (CMB) yang diperoleh dari misi Wilkinson Microwave Anisotropy Probe (WMAP), serta memainkan peran penting selama proses pengolahan data. Sebelumnya, kami menemukan ketidaksinkronan waktu sebesar -25,6 ms antara cap waktu dari sikap pesawat luar angkasa dan keluaran radiometer dalam data terurut waktu (TOD) mentah WMAP asli, yang jika tidak dikoreksi dalam pengolahan data selanjutnya, akan menghasilkan komponen kuadrupol buatan (l=2) dalam peta CMB yang diperoleh kembali (Liu, Xiong & Li 2010). Baru-baru ini, Roukema (2010b) membuktikan bahwa memang terdapat kesalahan akibat offset waktu yang sesuai dengan sekitar -25,6 ms dalam data TOD terkalibrasi WMAP dengan mempelajari varians fluktuasi per piksel dalam peta suhu yang diperoleh dari TOD sebagai fungsi dari offset waktu yang diasumsikan. Di sini, kami menemukan bukti langsung dalam data TOD WMAP mengenai kesalahan waktu yang tidak dikoreksi tersebut, yang kemungkinan terjadi dalam perhitungan sinyal dipol Doppler selama pengolahan data TOD oleh tim WMAP. Amplitudonya sangat signifikan dan konsisten dengan penelitian sebelumnya. Kami juga menunjukkan bahwa offset waktu yang tidak dikoreksi dapat menyebabkan kuadrupol CMB WMAP diperkirakan secara berlebihan.
|
id
|
We report the discovery of the minor planet 2003 VB12 (popularly named Sedna), the most distant object ever seen in the solar system. Pre-discovery images from 2001, 2002, and 2003 have allowed us to refine the orbit sufficiently to conclude that 2003 VB12 is on a highly eccentric orbit which permanently resides well beyond the Kuiper belt with a semimajor axis of 480$\pm$40 AU and a perihelion of 76$\pm$4AU. Such an orbit is unexpected in our current understanding of the solar system, but could be the result of scattering by a yet-to-be-discovered planet, perturbation by an anomalously close stellar encounter, or formation of the solar system within a cluster of stars. In all of these cases a significant additional population is likely present, and in the two most likely cases 2003 VB12 is best considered a member of the inner Oort cloud, which then extends to much smaller semimajor axes than previously expected. Continued discovery and orbital characterization of objects in this inner Oort cloud will verify the genesis of this unexpected population.
|
我们报告发现了小行星2003 VB12（通俗称为塞德娜），这是迄今为止在太阳系中观测到的最遥远的天体。通过2001年、2002年和2003年的早期影像资料，我们得以充分精确地确定其轨道，从而得出结论：2003 VB12运行在一个高度偏心的轨道上，该轨道始终位于柯伊伯带之外，其半长轴为480±40天文单位，近日点为76±4天文单位。根据我们目前对太阳系的理解，这样的轨道是出乎意料的，但它可能是由一颗尚未发现的行星的散射作用、一颗异常接近的恒星近距离飞掠的扰动，或太阳系在恒星团中形成所致。在所有这些情况下，很可能存在一个显著的额外天体群体；而在其中两种最可能的情形下，2003 VB12应被视为内奥尔特云的成员，这意味着内奥尔特云延伸至比此前预期小得多的半长轴范围。持续发现并确定这类内奥尔特云天体的轨道特征，将有助于验证这一意外群体的起源。
|
zh
|
The focus of this paper is directed towards optimal control of multi-agent systems consisting of one leader and a number of followers in the presence of noise. The dynamics of every agent is assumed to be linear, and the performance index is a quadratic function of the states and actions of the leader and followers. The leader and followers are coupled in both dynamics and cost. The state of the leader and the average of the states of all followers (called mean-field) are common information and known to all agents; however, the local state of the followers are private information and unknown to other agents. It is shown that the optimal distributed control strategy is linear time-varying, and its computational complexity is independent of the number of followers. This strategy can be computed in a distributed manner, where the leader needs to solve one Riccati equation to determine its optimal strategy while each follower needs to solve two Riccati equations to obtain its optimal strategy. This result is subsequently extended to the case of the infinite horizon discounted and undiscounted cost functions, where the optimal distributed strategy is shown to be stationary. A numerical example with $100$ followers is provided to demonstrate the efficacy of the results.
|
O foco deste artigo está voltado para o controle ótimo de sistemas multiagentes compostos por um líder e um número de seguidores na presença de ruído. Assume-se que a dinâmica de cada agente é linear, e o índice de desempenho é uma função quadrática dos estados e ações do líder e dos seguidores. O líder e os seguidores estão acoplados tanto na dinâmica quanto no custo. O estado do líder e a média dos estados de todos os seguidores (chamada campo médio) são informações comuns e conhecidas por todos os agentes; no entanto, o estado local dos seguidores é informação privada e desconhecida aos demais agentes. Demonstra-se que a estratégia ótima de controle distribuído é linear variante no tempo, e sua complexidade computacional é independente do número de seguidores. Essa estratégia pode ser calculada de maneira distribuída, em que o líder precisa resolver uma única equação de Riccati para determinar sua estratégia ótima, enquanto cada seguidor precisa resolver duas equações de Riccati para obter sua estratégia ótima. Este resultado é posteriormente estendido ao caso de funções de custo com horizonte infinito com e sem desconto, em que a estratégia ótima distribuída é mostrada ser estacionária. Um exemplo numérico com $100$ seguidores é apresentado para demonstrar a eficácia dos resultados.
|
pt
|
We further develop a thermal LB model for multiphase flows. In the improved model, we propose to use the FFT scheme to calculate both the convection term and external force term. The usage of FFT scheme is detailed and analyzed. By using the FFT algorithm spatiotemporal discretization errors are decreased dramatically and the conservation of total energy is much better preserved. A direct consequence of the improvement is that the unphysical spurious velocities at the interfacial regions can be damped to neglectable scale. Together with the better conservation of total energy, the more accurate flow velocities lead to the more accurate temperature field which determines the dynamical and final states of the system. With the new model, the phase diagram of the liquid-vapor system obtained from simulation is more consistent with that from theoretical calculation. Very sharp interfaces can be achieved. The accuracy of simulation results are also verified by the Laplace law. The FFT scheme can be easily applied to other models for multiphase flows.
|
เราได้พัฒนาแบบจำลองแลตทิซโบลต์ซมันน์เชิงความร้อนสำหรับการไหลแบบหลายเฟสเพิ่มเติม สำหรับแบบจำลองที่ปรับปรุงนี้ เราเสนอให้ใช้ขั้นตอนวิธีเอฟเอฟที (FFT) ในการคำนวณทั้งเทอมการพาความร้อนและเทอมแรงภายนอก ได้มีการอธิบายและวิเคราะห์การใช้ขั้นตอนวิธีเอฟเอฟทีอย่างละเอียด โดยการใช้ขั้นตอนวิธีเอฟเอฟที ความผิดพลาดจากการแบ่งช่วงเชิงพื้นที่และเวลาจะลดลงอย่างมาก และการอนุรักษ์พลังงานรวมก็ถูกคงไว้ได้ดียิ่งขึ้น ผลโดยตรงของการปรับปรุงนี้คือ ความเร็วเทียมที่ไม่เป็นจริงในบริเวณแนวแบ่งเฟสสามารถลดลงจนเกือบเป็นศูนย์ ร่วมกับการอนุรักษ์พลังงานรวมที่ดีขึ้น ความเร็วของการไหลที่แม่นยำยิ่งขึ้นจึงนำไปสู่สนามอุณหภูมิที่แม่นยำยิ่งขึ้น ซึ่งเป็นตัวกำหนดสถานะพลวัตและสถานะสุดท้ายของระบบ ด้วยแบบจำลองใหม่นี้ แผนภาพเฟสของระบบของเหลว-ไอที่ได้จากการจำลองมีความสอดคล้องกับผลการคำนวณเชิงทฤษฎีมากยิ่งขึ้น นอกจากนี้ยังสามารถได้รับแนวแบ่งเฟสที่คมชัดมากอีกด้วย ความแม่นยำของผลการจำลองยังได้รับการยืนยันเพิ่มเติมจากกฎของลาปลาซ ขั้นตอนวิธีเอฟเอฟทีสามารถนำไปประยุกต์ใช้กับแบบจำลองอื่นๆ สำหรับการไหลแบบหลายเฟสได้อย่างง่ายดาย
|
th
|
The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry, and hallmarks the issue for future colliders. As part of its HL-LHC upgrade program, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The ECAL and a large fraction of HCAL will be based on hexagonal silicon sensors of 0.5-1cm$^{2}$ cell size, with the remainder of the HCAL based on highly-segmented scintillators with SiPM readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection. An overview of the HGCAL project is presented, covering motivation, engineering design, readout and trigger concepts, and performance (simulated and from beam tests).
|
اعلیٰ شدت LHC (HL-LHC) LHC کے مقابلے میں 10 گنا زیادہ شدت کو یکجا کرے گا، جس سے خصوصاً فارورڈ کیلوری میٹری کے لیے ڈیٹیکٹرز پر تابکاری برداشت کرنے اور واقعات کے ڈھیر ہونے کے لحاظ سے نمایاں چیلنجز جنم لیں گے، اور مستقبل کے کولائیڈرز کے لیے اس مسئلے کی نشاندہی کرے گا۔ اپنے HL-LHC اپ گریڈ پروگرام کے حصے کے طور پر، CMS تعاون ایک اعلیٰ ذرّہ کیلوری میٹر کی تجویز پر کام کر رہا ہے جو موجودہ اینڈ کیپ کیلوری میٹرز کی جگہ لے گا۔ اس میں برقی مقناطیسی (ECAL) اور ہیڈرونک (HCAL) دونوں خانوں کے لیے بے مثال عرضی اور طویل عرصے تک تقسیم کی خصوصیت ہوگی۔ اس سے ذرّہ کے بہاؤ کی کیلوری میٹری کو آسانی ہوگی، جہاں شاورز کی باریک ساخت کو ناپا جا سکے گا اور ڈھیر ہونے کی مستردگی اور ذرّہ کی شناخت کو بہتر بنانے کے لیے استعمال کیا جا سکے گا، جبکہ توانائی کی اچھی درستگی حاصل کی جاتی رہے گی۔ ECAL اور HCAL کا ایک بڑا حصہ 0.5-1cm$^{2}$ خانے کے سائز والے شش ضلعی سلیکان سینسرز پر مبنی ہوگا، جبکہ HCAL کا باقی حصہ SiPM ریڈ آؤٹ کے ساتھ شدید طور پر تقسیم شدہ سائنسیلیٹرز پر مبنی ہوگا۔ سلیکان سینسرز کی اندرونی اعلیٰ درستگی والی ٹائمنگ کی صلاحیت واقعہ کی تعمیر میں ایک اضافی بعد شامل کرے گی، خاص طور پر ڈھیر ہونے کی مستردگی کے لحاظ سے۔ HGCAL منصوبے کا ایک جائزہ پیش کیا گیا ہے، جس میں حوصلہ افزائی، انجینئرنگ کی تجویز، ریڈ آؤٹ اور ٹرگر کے تصورات، اور کارکردگی (تشبیہاتی اور بیم ٹیسٹس سے حاصل شدہ) کا احاطہ کیا گیا ہے۔
|
ur
|
We report a fully quantum-dynamical study of the intramolecular vibrational energy redistribution (IVR) in the electronic ground state of carbonyl sulfide (OCS), which is a prototype of an isolated many-body quantum system with strong internal couplings and non-Rice-Ramsperger-Kassel-Marcus (RRKM) behavior. We pay particular attention to the role of many-body localization and the approach to thermalization, which currently are topics of considerable interest, as they pertain to the very foundations of statistical mechanics and thermodynamics. We employ local-mode (valence) coordinates and consider initial excitations localized in one local mode, with energies ranging from low to near the dissociation threshold, where the classical dynamics have been shown to be chaotic. We propagate the nuclear wavepacket on the potential energy surface by means of the numerically exact multiconfiguration time-dependent Hartree method and employ mean local energies, time-dependent and time-averaged populations in quantum number space, energy distributions, entanglement entropies, local population distributions, microcanonical averages, and dissociation probabilities, as diagnostic tools. This allows us to identify a continuous localization $\rightarrow$ delocalization transition in the energy flow, associated with the onset of quantum chaos, as the excitation energy increases up to near the dissociation threshold. Moreover, we find that at this energy and $\sim$1 ps the molecule nearly thermalizes. Furthermore, we observe that IVR is so slow that the molecule begins to dissociate well before such quasi-thermalization is complete, in accordance with earlier classical-mechanical predictions of non-RRKM behavior.
|
Iniuulat namin ang isang ganap na pagsusuri batay sa quantum-dinamika ng intramolecular vibrational energy redistribution (IVR) sa elektronikong pundamental na estado ng carbonyl sulfide (OCS), na siyang isang prototipo ng bulagsak na maramihang katawan na sistemang quantum na may malalakas na panloob na ugnayan at di-Rice-Ramsperger-Kassel-Marcus (RRKM) na pag-uugali. Binibigyang-pansin namin nang husto ang papel ng maramihang katawan na lokalizasyon at ang pagtungo patungo sa thermalization, na kasalukuyang mga paksa ng malaking interes dahil nauugnay ito sa mismong pundasyon ng istatistikal na mekanika at thermodynamics. Gumagamit kami ng local-mode (valence) na mga koordinado at isinasaalang-alang ang paunang mga pagkabigla na nakalokalisa sa isang local mode, na may enerhiya mula mababa hanggang malapit sa threshold ng dissociation, kung saan ang klasikal na dinamika ay ipinakita nang magkaos. Pinapalaganap namin ang nukleyar na wavepacket sa ibabaw ng potensyal na enerhiya sa pamamagitan ng numerikal na eksaktong multiconfiguration time-dependent Hartree na paraan at gumagamit ng mean local na enerhiya, time-dependent at time-averaged na populasyon sa quantum number space, pamamahagi ng enerhiya, entanglement entropies, pamamahagi ng lokal na populasyon, microcanonical averages, at mga posibilidad ng dissociation, bilang mga kasangkapan sa pagsusuri. Nang dahil dito, nakilala namin ang tuluy-tuloy na transisyon mula lokalizasyon patungo sa delokalizasyon sa daloy ng enerhiya, na kaugnay ng pagsisimula ng quantum chaos, habang tumataas ang enerhiya ng pagkabigla hanggang malapit sa threshold ng dissociation. Bukod dito, natuklasan namin na sa enerhiyang ito at ∼1 ps, halos naa-thermalize na ang molekula. Higit pa rito, napansin namin na ang IVR ay napakabagal kaya ang molekula ay nagsisimulang mag-dissociate nang maaga bago pa man kumpletuhin ang ganitong kahalintulad ng thermalization, ayon sa mga naunang klasikal-mekanikal na prediksyon ng di-RRKM na pag-uugali.
|
tl
|
The relationship between variability, luminosity and redshift in the South Galactic Pole QSO sample is examined in an effort to disentangle the effects of luminosity and redshift in the amplitude of the optical variations. The anticorrelation between variability and luminosity found by other authors is confirmed. Our analysis also supports claims that variability increases with redshift, most likely due to an anticorrelation between variability and wavelength. In particular, our parametric fits show that the QSO variability-wavelength relation is consistent with that observed in low-luminosity nearby active galactic nuclei. The results are used to constrain Poissonian-type models. We find that if QSO variability results from a random superposition of pulses, then the individual events must have B-band energies between $\sim 10^{50}$ and a few times $10^{51}$ erg and time-scales of $\sim 2$ yr. Generalized Poissonian models in which the pulse energy and lifetime scale with luminosity are also discussed.
|
Исследуется связь между изменчивостью, светимостью и красным смещением в выборке квазизвёздных объектов в области Южного галактического полюса с целью разделения влияния светимости и красного смещения на амплитуду оптических вариаций. Подтверждается антикорреляция между изменчивостью и светимостью, обнаруженная другими авторами. Наш анализ также поддерживает утверждения о том, что изменчивость возрастает с красным смещением, вероятнее всего из-за антикорреляции между изменчивостью и длиной волны. В частности, наши параметрические аппроксимации показывают, что зависимость изменчивости квазизвёздных объектов от длины волны согласуется с той, которая наблюдается в близких активных галактических ядрах низкой светимости. Полученные результаты используются для ограничения моделей пуассоновского типа. Мы обнаружили, что если изменчивость квазизвёздных объектов обусловлена случайным наложением импульсов, то отдельные события должны иметь энергии в B-диапазоне между ∼10⁵⁰ и несколькими 10⁵¹ эрг и временные масштабы около 2 лет. Также обсуждаются обобщённые пуассоновские модели, в которых энергия импульса и его продолжительность зависят от светимости.
|
ru
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.