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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.
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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。
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ja
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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.
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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。
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ja
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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.
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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.
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lo
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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.
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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.
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ru
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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.
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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.
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ar
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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.
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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.
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vi
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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.
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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.
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ar
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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.
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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۔
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ur
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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.
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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.
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ru
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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.
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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。
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zh
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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 $r$.
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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 $r$.
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cs
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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.
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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។
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km
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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.
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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.
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cs
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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.
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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।
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bn
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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.
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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۔
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ur
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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.
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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.
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pt
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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.
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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.
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tl
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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.
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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.
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lo
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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.
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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.
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cs
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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.
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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។
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km
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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.
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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।
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bn
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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.
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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.
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cs
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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.
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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
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th
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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.
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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.
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tr
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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.
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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.
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vi
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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.
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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。
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zh
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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.
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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.
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pt
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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.
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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។
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km
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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.
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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။
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my
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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.
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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។
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km
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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.
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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.
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cs
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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.
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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.
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lo
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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.
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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.
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fr
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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.
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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.
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de
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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.
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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。
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ja
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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.
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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.
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ru
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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.
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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.
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lo
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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.
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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.
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ar
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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.
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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។
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km
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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.
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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。
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zh
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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.
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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।
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bn
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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.
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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
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th
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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.
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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.
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de
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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.
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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۔
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ur
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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.
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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။
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my
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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.
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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۔
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ur
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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 $V(\phi)$.
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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。
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zh
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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.
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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.
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es
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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.
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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។
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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.
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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។
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