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16,300 | Please write an abstract with title: Broadband Transmission Properties of cBN-Si Interfaces, and key words: Optical attenuators, Reflectivity, Optical reflection, Optical films, Silicon, Optical filters, Optical devices. Abstract: We analyze the real and imaginary parts of cBN in a broad wavelength range both 0.5-1.0 μm and 1.36-10 μm respectively, and use both Fresnel theory and Meep software package to calculate the transmittance and reflectance. The theoretical and numerical results show that the transmision and reflection on the interfaces mentioned above have an abnormal phenomenon, and the physical mechanism is analyzed. Between 0.5 μm and 1 μm, the cBN film is transparent with the transmissivity equal to the order of 1.0. When the light wavelength is in the range of 4-9 μm, the structures made of cBN and Si, such as cBN film, cBN-Si double layer film and multiple layer film, have the same optical characteristic with the highest reflectivity and lower absorptivity and zero transmissivity. These findings can be used in the structure design of the optoelectronic devices, such as the optical bandpass filter, the optical bandstop filter, the optical attenuator, the photodetector, and the solar cell. |
16,301 | Please write an abstract with title: USV Obstacle Avoidance Based on Improved Watershed and VFH Method, and key words: Image segmentation, Collision avoidance, Navigation, Planning, Marine vehicles, Histograms, Image reconstruction. Abstract: In recent years, with the rapid development of unmanned surface vessel (USV), a real-time collision avoidance system is required to guarantee its safety navigation in the practical marine engineering. Therefore, this paper firstly uses wavelet transform technology to decompose and reconstruct the image collected by USV, so as to achieve the effect of denoising, and mark the foreground and background information. Then, the improved watershed segmentation method is used to segment the target object. Finally, a vector field histogram (VFH) method is proposed, which can solve the collision avoidance problem of USV from high dimension to low dimension based on the segmented image. The calculation burden is greatly low, and the real-time collision avoidance can be realized at the same time. |
16,302 | Please write an abstract with title: Thermal design methodology for high-heat-flux single-phase and two-phase micro-channel heat sinks, and key words: Design methodology, Heat sinks, Temperature, Heat transfer, Predictive models, Electronics cooling, Drag, Thermal conductivity, Thermal resistance, Numerical simulation. Abstract: This paper explores several issues important to the thermal design of single-phase and two-phase micro-channel heat sinks. The first part of the paper concerns single-phase heat transfer in rectangular micro-channels. Experimental results are compared with predictions based on both numerical as well as fin analysis models. While the best agreement between predictions and experimental results was achieved with numerical simulation, a few of the fin models are found to provide fairly accurate predictions. The second part of the paper focuses on predicting the incipient boiling heat flux. A comprehensive model based on bubble departure and superheat criteria is developed and validated with experimental data. The incipience model is capable of predicting the location, shape and size of bubbles departing in rectangular micro-channels. In the third part of the study, an analytical model is developed to predict pressure drop across a two-phase micro-channel heat sink. This model provides a detailed assessment of pressure drop concerns with two-phase micro-channels, including compressibility, flashing and choking. Overall, the present study provides important guidelines concerning practical implementation of micro-channel heat sinks in high-heat-flux electronic cooling applications. |
16,303 | Please write an abstract with title: Nonvolatile solid-state memory, and key words: Nonvolatile memory, Solid state circuits, Instruments, Military computing, Consumer electronics, Read only memory, Tiles, EPROM, Magnetic semiconductors, Writing. Abstract: New developments in nonvolatile solid-state memory promise users a spectrum of technologies for various degrees of programmability/reprogrammability. These advancements in such areas as low-power MOS, EPROM, EEPROM and magnetic bubbles will be discussed from the standpoint of functionality, performance, cost and availability as related to application. Long range projections of capability will also be offered. |
16,304 | Please write an abstract with title: An Active Voltage Balancing Strategy for Stacked-Inverter ICN Converters, and key words: Prototypes, Rectifiers, Switches, Resonant converters, Zero voltage switching, Control systems, Transformers. Abstract: This paper presents an active voltage balancing strategy for the impedance control network (ICN) resonant converters with stacked inverters. The stacked mode of operation of this converter is analyzed in detail and the reason for the voltage imbalance is discussed. An active voltage balancing strategy leveraging the phase-shift between the converter’s inverter and rectifier is proposed to mitigate this voltage imbalance. The impact of this voltage balancing strategy on the converter’s soft-switching capability is examined and an enhancement to this balancing strategy is also proposed to ensure soft-switching by introducing slight voltage imbalance. The proposed voltage balancing strategy and its enhanced version are experimentally validated using a 20-V, 330-W ICN ac-dc converter prototype operating at high line input (230 Vrms). This prototype achieves a peak efficiency of 93.8% at high line. |
16,305 | Please write an abstract with title: A Compressive Sensing Imaging System Using Multimode Fiber, and key words: Image coding, Laser mode locking, Imaging, Optical fiber networks, Speckle, Generators, Sensors. Abstract: A compressive sensing (CS) imaging system employing a multimode fiber is proposed. Broadband light from mode-locked laser goes through a multimode fiber and then produces speckles, which are randomly distributed and ideal for CS imaging. The proposal has the merits of low-cost and easy access compared with the traditional CS method using pseudorandom binary sequence (PRBS). What's more, the utilization of CS method and photonic time stretch (PTS) technique could achieve ultrafast CS imaging. In this work, the randomly distributed speckles are experimentally investigated and utilized to demonstrate the proposed CS imaging. The demonstrated result illustrates a 27 × 27 pixels image is recovered with varied compression ratios. |
16,306 | Please write an abstract with title: The effect of impedance mismatch on the conducted EMI emission, and key words: Impedance, Electromagnetic interference, Circuits, Zero voltage switching, Resonant inverters, Reactive power, Switches, Laboratories, Capacitors, Frequency. Abstract: The paper proposes a process to predict and analyze conducted electromagnetic interference (EMI) emission using the impedance mismatch approach. Five steps of this process are introduced and analyzed. The impedance mismatch criterion is proposed based on current and voltage waveforms in the time domain. The impedance mismatch fixtures and EMI measured results show how the impedance ratio and conducted EMI emission are related. The work was done using a class E zero-voltage switching (ZVS) resonant inverter at various load conditions - unity, lagging and leading power factors. The experimental results show good agreement with simulated results, which are accomplished by the MATLAB program. |
16,307 | Please write an abstract with title: Progress of CW and short-pulse calorimetric loads for high power millimeter-wave beams, and key words: Testing, Millimeter wave measurements, Pulse measurements, Absorption, Atmospheric waves, Atmospheric measurements, Power measurement, Wavelength measurement, Gyrotrons, Bolometers. Abstract: A family of compact matched loads for high power millimeter wavelength beams absorption, good for atmospheric and vacuum operation, suited for CW (1MW) or short pulses (2MW, 0.ls) precise measurement has been designed to test high power gyrotrons. The common origin for members of this family is a toad developed for the ECRH FTU plant (140 GHz, 0.5 s, 0.5 MW) and successfully exploited. A CW version of the load has been built and used as absorber and bolometer for the high-power test of a remote steering launcher mock-up at 140 GHz. The high-power tests have been performed with powers up to 700 kW and pulse lengths of up to 10 seconds without limitation due to the load. An investigation of the gas emission properties of the load coating material at high temperature and under vacuum has been accomplished by means of high power deposition from an electron gun. Results from these tests are presented. |
16,308 | Please write an abstract with title: Design and Analysis of PID, Type II and Type III controllers for Fourth Order Boost Converter, and key words: Fluctuations, Power supplies, Power grids, Steady-state, Performance analysis, Voltage control, Transient analysis. Abstract: There are a variety of DC-DC converters which are applied in several industrial applications such as power supplies and power grids. In such cases, the control of power converters become difficult for varying input voltage and output load currents. A classical PID controller is designed for keeping track of the voltage regulation and it has been further optimized based on the rise time and settling time to Type II and Type III controller for a comparatively better performance. The comparison of the different controllers is done for a better performance analysis. The steady state and the transient analysis of the closed loop converter are analysed in this paper. |
16,309 | Please write an abstract with title: A Review on Social Network Analysis Methods and Algorithms, and key words: Deep learning, Machine learning algorithms, Social networking (online), Multimedia Web sites, Clustering algorithms, Evolutionary computation, Nonhomogeneous media. Abstract: Social network-based applications like Facebook, Twitter, and Instagram have been used by people of all age groups and backgrounds for the last few years. It is a rich platform for sharing knowledge amongst users online. This information is shared as feelings, opinions, interests, events, or comments in large volumes and varied forms of data. Many multidisciplinary researchers have conducted studies to find out the commercial values of social media data. The reason behind this interest in research is an affluence to access data from the web, process it, and pull-out useful information from the web. Researchers have worked upon and explored the topics like information spreading, relationship analysis in groups for some or other applications. This review paper conducts a survey on community detection problem in social networks, its analysis, and a study of research done on related areas. |
16,310 | Please write an abstract with title: Cultural Tourism Management Platform Based on Personalized Recommendation Algorithm, and key words: User experience, Cultural differences, Time factors, Smart phones, Autonomous robots. Abstract: Tourism is a way for people to relax in today's era. How to learn local cultures and satisfy users' leisure experience in tourism requires the development of a tourism platform that suits the needs of tourists. According to the needs of platform development, this paper designs a cultural tourism management based on a personalized recommendation algorithm, which can be used to analyze users' travel preferences and recommend scenic spots and surrounding information. The platform integrates cultural tourism resources from all over the world, provides online browsing of cultural tourism information, and applies personalized recommendation technology to the platform to achieve precise connection of tourism resources, thereby enhancing user experience and promoting tourism market revenue. In the research and analysis of the corresponding performance test of the platform and the satisfaction survey of the recommendation results, it is shown that the performance of the platform meets the operating requirements and the user's expectations. |
16,311 | Please write an abstract with title: Research on Reactive Power Compensation Based on Magnetic Saturation Controllable Reactor, and key words: Inductors, Saturation magnetization, Reactive power, Magnetic cores, Magnetic circuits, Magnetic flux, Power systems. Abstract: With the improvement of the automation level of the power system and the development of power electronic equipment, the magnetic saturation controllable reactor will surely become indispensable reactive power compensation equipment. But there are few researches on it at home and abroad. In the power system with its superior performance the magnetic saturation controllable reactor studied in this article is a static dynamic reactive power compensation device, which mainly uses lagging inductive reactive power to offset the leading capacitive reactive power. In this paper, its structure and working principle are studied in detail, electromagnetic calculation and simulation analysis are carried out, and genetic algorithm is introduced to optimize it. From theory to practice, a thorough discussion is made to make up for the blank of this direction. |
16,312 | Please write an abstract with title: Scattering from an abruptly terminated dielectric-slab waveguide, and key words: Dielectrics, Electromagnetic waveguides, Slabs, Integral equations, Electromagnetic scattering, Surface waves, Planar waveguides, Tellurium, Magnetic fields, Refractive index. Abstract: Scattering of surface waves from an abruptly terminated dielectric-slab waveguide is investigated analytically, by means of an integral equation appropriate for the boundary-value problem of TE modes. In order to obtain a tractable solution to the equation, a Neumann Series iterative procedure is applied. Numerical results are given in several cases of abruptly ended dielectric slabs. Particular attention is directed to the behavior of electric and magnetic fields at the plane of discontinuity, since field distributions at any other region depend directly on these surface values. |
16,313 | Please write an abstract with title: SPSN: Seed Point Selection Network in Point Cloud Instance Segmentation, and key words: Three-dimensional displays, Measurement, Feature extraction, Proposals, Image segmentation, Semantics, Object detection. Abstract: The current mainstream point cloud instance segmentation methods are mainly divided into two steps. Firstly, the points of each instance are aggregated in the feature space by means of metric learning to make the features of the same instance are as similar as possible, and then the aggregated vector clusters are segmented to construct the proposal of each instance. Much of the previous work has focused on the aggregation of vectors and ignored how the instance is divided after the vector aggregation. In this paper, we propose a seed point selection network. The seed point selection network selects a better seed point generation proposal by judging the "seedness" of each point, and completes the instance-level segmentation of all points. In addition, the speed of instance segmentation effectively improved by the fast processing of the generated instance points and the low "seedness" points. In the experiment, we graft the seed point selection network onto different instance segmentation networks, and the accuracy and efficiency of segmentation are improved in different degrees. |
16,314 | Please write an abstract with title: Modelling of a tunnel dryer with a bond graph approach, and key words: Temperature measurement, Temperature distribution, Atmospheric modeling, Loss measurement, Electrical resistance measurement, Convection, Resistance heating. Abstract: In this research work, a bond graph model of a tunnel dryer is performed. The tunnel dryer is sustained by a centrifugal blower. A set of heating resistances are placed inside the tunnel dryer. A detailed model of the centrifugal blower is built. Special importance is attributed to the modelling of the convection between heating resistances and internal air. The resulting model is an energetic lumped approach to simulate the temperature at the output of the tunnel dryer. Data temperature acquired from an experimental tunnel dryer are confronted to the simulated one to validate the model. The simulated results match correctly the measured one. |
16,315 | Please write an abstract with title: Hybrid Entropy in the Time-Frequency Domain for Grading Electrode Sediment Identification, and key words: Sediments, Electrodes, Entropy, Feature extraction, Acoustics, Valves, Indexes. Abstract: The traditional manual periodic screening method of grading electrode sediments is prone to cause the equipment failure of high voltage direct current converter valves. Therefore, we propose to use ultrasonic time-domain reflection method to detect the sediments. However, the ultrasonic echo signals are characterized by nonlinearity and nonsmoothness, which makes it very difficult to extract effective features for sediment detection. To address this issue, we propose an intelligent detection method based on multiscale hybrid entropy characteristics in the time-frequency domain. First, a multiscale decomposition of the signal is performed. Second, the weighted form factor index is proposed to select the noise modes. Moreover, we propose to calculate the hybrid entropy in the time-frequency domain of each mode as the characteristic input bidirectional long and short-term memory network model, and verified that feature enhancement can be achieved by noise modes noise reduction. Finally, the experimental validation shows that the proposed method can achieve nondestructive testing and intelligent identification of graded electrode sediment with a correct identification rate of 94.25%. |
16,316 | Please write an abstract with title: Low-Cost Implementation of Independent Component Analysis for Biomedical Signal Separation Using Very-Large-Scale Integration, and key words: Electrocardiography, Signal processing algorithms, Source separation, Very large scale integration, Electroencephalography, Table lookup. Abstract: This brief proposes a low-cost implementation of the extended InfoMax independent component analysis (ICA) algorithm for biomedical signal separation by using very-large-scale integration (VLSI). On the basis of this algorithm, the implemented VLSI ICA core can be used to separate a mixed signal from a super-Gaussian signal source. By using mathematical operations of merging and simplification, the ICA core uses the systolic array and lookup table to implement the extended InfoMax ICA algorithm, thus achieving low cost and high speed. The measured results indicated that the ICA core consumed 9.5 mW when operated at 100 MHz using TSMC 90-nm complementary metal-oxide-semiconductor technology, with a gate count of only 36.8K. This represents a 59% reduction in area and a 35% saving in power compared with the previous design. Furthermore, the proposed ICA core was applied to mixed electrocardiogram signals, and the separated signals exhibited excellent quality. |
16,317 | Please write an abstract with title: Finite-time Attitude Tracking for Spacecraft With Unknown Boundary Disturbance and Angular Velocity, and key words: Observers, Space vehicles, Attitude control, Angular velocity, Lyapunov methods, Convergence, Symmetric matrices. Abstract: This paper investigates a velocity-free finite-time attitude control scheme for rigid spacecrafts with unknown boundary external disturbance. By using the quadratic Lyapunov function (QLF) method, a finite-time observer is designed to estimate unknown angular velocity and boundary of external disturbance. Combining adaptive control technique with adding a power integrator (AAPI), a finite-time controller is proposed. Rigorous Lyapunov-based analysis shows that both the observation errors and tracking errors can converge to the equilibrium point in finite time under the designed control law. Numerical simulation results illustrate the performance of the proposed control scheme. |
16,318 | Please write an abstract with title: On Streaming Codes With Unequal Error Protection, and key words: Codes, Delays, Error correction codes, Decoding, Low latency communication, Streaming media, Real-time systems. Abstract: Error control codes for real-time interactive applications such as audio and video streaming must operate under strict delay constraints and be resilient to burst losses. Previous works have characterized optimal streaming codes that guarantee perfect and timely recovery of all source packets when the burst loss is below a certain maximum threshold. In this work, we generalize the notion of streaming codes to the unequal error protection (UEP) setting. Toward this end, we define two natural notions of streaming codes; symbol-level UEP and packet-level UEP. In the symbol-level UEP, the symbols within each source packet have varying recoverability requirements. In the packet-level UEP scenario, packets at even time slots and odd time slots have different recovery guarantees. We discuss practical motivations for both settings and develop coding schemes. We establish optimality or near-optimality guarantees through information-theoretic converse bounds. Simulations over Gilbert and Fritchman channels show that our coding schemes outperform baseline schemes over a wide range of channel parameters. |
16,319 | Please write an abstract with title: New FPGA architecture for 8, 16 and 24 bit chaotic interleaver, and key words: VHDL, Software packages, Simulation, Forward error correction, Mathematical models, Generators, Encoding. Abstract: In a digital system, the interleaver is essential. It’s widely used to enhance the effectiveness of forward error correction codes. A lot of research has shown the efficiency of the chaotic interleaver in correcting the 2d burst error. We used this type of interleaver based on the baker map equation. The problem with using such encoding technique is in adaptive in multi standard systems stream of bit can be 8, 16, and 24 hence there is a need for three types of interleavers which increase the complexity of the system. In this paper, an efficient chaotic interleaver model was presented with a new FPGA architecture that includes 8-, 16- and 24-bit square matrix. This new design makes the system easily deal with more than one size of the matrix input to the system and this is called a multi-standard system instead of having each size separately in its own design. The results were obtained using the Xilinx ISE 14.7 design suite. In the system generator, the generated waveforms are viewed using the scope block of Simulink. |
16,320 | Please write an abstract with title: Engineering Doctoral Student Perceptions of Research Task Difficulty and the Student-Advisor Relationship, and key words: Task analysis, Medical services, Correlation, Standards, Linear regression, STEM. Abstract: The purpose of this work in progress (WIP) research paper is to examine the relationship between engineering doctoral students' perceptions of their research task difficulties and advisor relationships. We used identity-based motivation (IBM) as a theoretical framework for this study. Specifically, we consider the construct interpretation of difficulty as it can serve to motivate or demotivate students. In a nationally representative survey, students ranked the level of difficulty they experienced conducting research tasks, such as writing and presenting. They also noted how they regard different aspects of their student-advisor relationships, including communication, expertise, and overall positivity of the relationship. Linear regression was performed to examine how the participants' perceptions of their student-advisor relationships predicted their perceptions of research task difficulty (n=1152). Results showed a weak but significant correlation between these variables, suggesting that student perceptions of their advisor relationships may be one of many variables that influence students' perceptions of research task difficulty. Through better understanding of the influence of doctoral students' perceptions of their advisor relationships on their perceptions of task difficulty, we can begin to create guidelines to improve advisors' interactions with their doctoral students to address long-standing persistent issues. |
16,321 | Please write an abstract with title: An efficient 3-D spectral-element method for Schro/spl uml/dinger equation in nanodevice simulation, and key words: Equations, Numerical analysis, Sparse matrices, Transmission line matrix methods, Eigenvalues and eigenfunctions, Interpolation, Gaussian processes, Polynomials, Moment methods, Finite element methods. Abstract: A three-dimensional (3-D) spectral-element method (SEM) based on Gauss-Lobatto-Legendre (GLL) polynomials is proposed to solve the Schro/spl uml/dinger equation in nanodevice simulation. Galerkin's method is employed to obtain the system equation. The high-order basis functions employed are orthogonal and the numerical quadrature points are the same as the GLL integration points, leading to a diagonal mass matrix and a more sparse stiffness matrix. Thus, the proposed method leads to a regular eigenvalue problem, rather than a generalized eigenvalue problem, greatly reducing the computer-memory requirement and central-processing-unit (CPU) time in comparison with the conventional finite-element method (FEM). Furthermore, the SEM is implemented for high geometrical orders, where curved structures can be modeled up to the accuracy comparable to the interpolation accuracy afforded by the basis functions. Numerical examples verify a spectral accuracy with the interpolation orders, and confirm that higher geometrical orders are essential for curved structures to achieve overall spectral accuracy. Examples of quantum dots in various structures, including a waveguide, are analyzed with mixed boundary conditions. Numerical results show that the SEM is an efficient alternative to conventional FEM and to the finite-difference method (FDM) for nanodevice simulation. |
16,322 | Please write an abstract with title: Estimating the essential matrix by efficient linear techniques, and key words: Biological system modeling, Layout, Computational geometry, Linear systems, Computational efficiency, Stereo vision, Machine vision, Computer vision, Application software, Cameras. Abstract: In the problem of recovering the 3D structure of a scene from its 2D projections, a fundamental low-level computer vision task is the estimation of the epipolar geometry. Accurate estimation of the epipolar geometry uses computationally expensive iteration schemes based on nonlinear algebraic constraints to deal with the ill-posedness of the problem. Linear techniques are computationally efficient but extremely unstable. Theoretical and practical aspects of linear methods are analyzed and fundamental results are derived from the study. Two main causes of instability are considered. The first one refers to the lack of homogeneity in the input data. To deal with this problem, a highly efficient scaling approach is introduced. The optimality of the technique is proven theoretically and heuristically. It is shown that a second source of instability arises from the linear dependency between rows of the matrix of the linear system. The effect of this problem in the estimation of the essential matrix is analyzed. An additional strategy is introduced to overcome this difficulty. This strategy improves the stability and accuracy of the linear approach even further while reducing the computational cost. Numerical experiments to evaluate the effectiveness of the proposed techniques are reported. |
16,323 | Please write an abstract with title: A single-electron-transistor logic gate family and its application - Part I: basic components for binary, multiple-valued and mixed-mode logic, and key words: Logic gates, Logic circuits, CMOS technology, MOSFET circuits, Voltage, Integrated circuit technology, CMOS logic circuits, Logic devices, Circuit synthesis, Logic functions. Abstract: This paper presents a model-based study of an SET (single-electron-transistor) logic gate family for synthesizing binary and MV (multiple-valued) logic circuits. The use of SETs combined with MOS transistors allows a compact realization of basic logic functions that exhibit periodic transfer characteristics. These basic SET logic gates are useful for implementing binary logic circuits, MV logic circuits and binary-MV-mixed logic circuits in a highly flexible manner. As an example, this paper describes the design of various parallel counters for carry-propagation-free arithmetic, where MV signals are effectively used to achieve higher functionality with lower hardware complexity. |
16,324 | Please write an abstract with title: Adjusting freight train paths to infrastructure possessions, and key words: Rail transportation, Maintenance engineering, Mathematical model, Delays, Turning, Schedules, Linear programming. Abstract: This paper tackles railway timetabling with infrastructure work possessions. It introduces the integrated Passenger and Freight Train Timetable Adjustment Problem (PF-TTAP) which handles both passenger as well as freight trains. To deal with possessions, passenger trains are typically retimed, reordered or partially cancelled, while for freight trains it is important to reach their destination, possibly using an alternative path. Alternative paths for freight trains are generated using the k-shortest path algorithm. To solve the PFTTAP, a mixed integer linear programming (MILP) problem is developed to simultaneously retime, reroute and cancel trains in the network. The model aims at minimizing deviations from the original timetable and in particular selecting alternative freight paths with the least turning activities and noncommercial stops. The model was tested on the Dutch national railway network. The PF-TTAP model successfully created an alternative hour pattern satisfying all the railway stakeholders. |
16,325 | Please write an abstract with title: Soft Sensor for VFA Concentration in Anaerobic Digestion Process for Treating Kitchen Waste Based on DSTHELM, and key words: Feature extraction, Mathematical model, Data mining, Monitoring, Neurons, Biological neural networks, Training. Abstract: Kitchen waste is both a pollutant and an available resource. The anaerobic digestion (AD) technology can effectively treat waste and generate biogas. The concentration of volatile fatty acids (VFA) is one of the essential quality monitoring indicators in the anaerobic digestion process of kitchen waste and is difficult to measure online. In this paper, the hierarchical extreme learning machine (HELM) is applied to the soft sensor for the concentration of VFA considering the shortcomings of traditional soft sensor. The combined feature information is extracted by the multi-layer extreme learning machine-autoencoder (ELM-AE) structure in the HELM. Besides, the last layer is the combined manifold regularization extreme learning machine (ELM) and used to predict and mine the data structure of labeled data and unlabeled data. Considering that the characteristics of system operating conditions are prone to change in the actual production process of anaerobic digestion, the domain space transfer hierarchical extreme learning machine (DSTHELM) is used to solve the data drift problem caused by different initial conditions in the actual data; this is different from the traditional hierarchical extreme learning machine. This method increases the accuracy by 14.31% and 9.67% in training set and test set compared with HELM, indicating that the model possesses higher prediction accuracy and better generalization performance. |
16,326 | Please write an abstract with title: Combining KPCA with support vector machine for time series forecasting, and key words: Support vector machines, Principal component analysis, Feature extraction, Kernel, Contracts, Risk management, Training data, Covariance matrix, High performance computing, Upper bound. Abstract: Recently, support vector machine (SVM) has become a popular tool in time series forecasting. In developing a successful SVM forecaster, the first important step is feature extraction. This paper applies kernel principal component analysis (KPCA) to SVM for feature extraction. KPCA is a nonlinear PCA developed by using the kernel method. It firstly transforms the original inputs into a high dimensional feature space and then calculates PCA in the high dimensional feature space. By examining the sunspot data and one real futures contract, the experiment shows that SVM by feature forms much better than that extraction using KPCA per without feature extraction. In comparison with PCA, there is also superior performance in KPCA. |
16,327 | Please write an abstract with title: A Novel 600V Lateral RESURF 4H-SiC MESFET with Sloped Field Plate for High Power and High Frequency Applications, and key words: Silicon carbide, Photonic band gap, Logic gates, MESFETs, Semiconductor process modeling, Electric fields, Passivation. Abstract: Silicon carbide (SiC) possesses a high breakdown field of 4×106 V/cm, high saturated electron drift velocity of 2×107 cm/s and excellent thermal conductivity of 4.9 W/cm' K attributing from its wide bandgap. These characteristics make this material attractive for incorporating new approaches in device design such as the RESURF (Reduced Surface Field) technology, which is an innovative method for designing lateral high-voltage, low onresistance devices. We have demonstrated a 600V Lateral RESURF 4H-SiC MESFET with sloped passivation which shows significantly higher power density as opposed to conventional RF GaAs devices and silicon LDMOS transistors. A sloped field plate structure is utilized to drain, source, and gate electrodes to reduce the surface electric field and significantly improve breakdown voltage up to 560V without sacrificing forward on-resistance. |
16,328 | Please write an abstract with title: Towards Model-Centric Security for IoT Systems, and key words: Data models, Security, Mathematical model, Computational modeling, Medical services, Robot sensing systems. Abstract: In this paper, we make a case for a novel model-centric security approach to the IoT application systems. We thus depart from the popular device-centric and data-centric schemes. Our proposal is based on the premise that the trained model, rather than the fine-grained input and output data streams, plays the pivotal role in many IoT application systems. We thus seek to obfuscate the model directly, but not the individual data items or sensory data streams. We present our initial design of sampling-based model obfuscation. Both evaluations and analysis have partially confirmed our design to date. |
16,329 | Please write an abstract with title: Improvement of the depth of interaction detector for PET on full energy pulse height uniformity, and key words: Detectors, Positron emission tomography, Optical pulses, Sensor arrays, Crystals, Cathodes, Surface finishing, Optical coupling, Histograms, Pulse circuits. Abstract: As part of the next generation PET project, uniformity of full energy pulse height for all crystal elements was improved in the depth of interaction (DOI) detector constructed of three-dimensional crystal arrays. In our previous report, we found that the DOI detector constructed of four stages of a 2 /spl times/ 2 Gd/sub 2/SiO/sub 5/:Ce (GSO) crystal array provides good crystal identification performance but poor uniformity of the energy pulse height distribution. The upper stage crystal elements which stay further from the photocathode of a PMT have a tendency to show lower energy pulse height. For example, the ratio of the full energy peak of the top stage crystal to the bottom stage one was about 0.3. We designed a new DOI detector improved in the uniformity. By optimizing crystal surface finishes, reflector configurations, and optical coupling between crystal elements, we got comparable energy pulse height from the upper stage crystals to the bottom stage crystals. Despite this change of detector conditions, good separation between each area corresponding to crystal elements is maintained on two-dimensional histograms obtained by Anger-type position calculation. The uniform full energy pulse height of every stage crystal allows a narrower dynamic range of the electrical circuits, and may give a great advantage in getting an accurate scatter correction. It also improves energy and timing resolution. |
16,330 | Please write an abstract with title: FedIM: An Anti-attack Federated Learning Based on Agent Importance Aggregation, and key words: Training, Privacy, Data privacy, Training data, Machine learning, Collaborative work, Data models. Abstract: Federated learning (FL) is a distributed framework for machine learning (ML) model training. Training agents upload local model parameters rather than original training data, and the central server performs parameter aggregation. FL can protect user data privacy and break the information island when training the ML model. Federated Average (FedAvg) is an aggregation method commonly used in the FL training task. The central server calculates the mean value of the local model parameters to obtain the new global parameters. FedAvg assumes that all the training agents are honest, which means the central server lacks terminal agents' knowability. When there are attackers in the training agents, the global model's performance may be deeply affected, and the training task cannot be completed normally. To solve this problem, we propose a Federated Learning method with aggregation based on the Importance of training agent (FedIM), in which the central server performs pre-evaluation on the agent parameters before aggregation, calculates the weights of parameters according to the historical behavior records of training terminals and performs federated aggregation to improve the anti-poisoning ability of learning task. Experiments show that our method can effectively improve the global model's anti-poisoning ability and accelerate the training speed compared with the FedAvg method when malicious agents are involved. |
16,331 | Please write an abstract with title: Spectroscopy of a single Al/sup +/ ion via coupling to Be/sup +/, and key words: Spectroscopy, Cooling, Clocks, Laser transitions, Optical scattering, Particle beam optics, Optical sensors, Laser modes, Stationary state, Frequency. Abstract: We perform precision spectroscopy on /sup 27/Al/sup +/ with the aid of a /sup 9/Be/sup +/ ion. Using sympathetic cooling and quantum state transfer, we efficiently interrogate the /sup 1/So /spl rarr/ /sup 3/Pi and /sup 1/So /spl rarr/ /sup 3/Po transitions. |
16,332 | Please write an abstract with title: FrAG: A Framework for the Analysis of Games, and key words: AI, reinforcement learning, binary reverse engineering, Atari 2600, archaeology, archaeogaming. Abstract: FrAG is a Framework for the Analysis of Games, allowing us to harness game-playing AI techniques to assist in the reverse engineering of historical video games for which the binary form of the game is the only thing remaining. Moreover, FrAG allows us to perform this task at scale, and search for patterns of game development that might otherwise be overlooked. Game development is done by humans, of course; our interdisciplinary approach is not exclusively technical, and also involves the field of archaeology and its well-established theories of humans and technology. Here we present FrAG’s architecture along with our preliminary results using the framework on a test suite of Atari 2600 games. |
16,333 | Please write an abstract with title: Novel highly nonlinear bismuth oxide fiber for supercontinuum generation, and key words: Bismuth, Supercontinuum generation, Optical fiber communication, Ultrafast optics, Biomedical optical imaging, Fiber nonlinear optics, Dispersion, Optical refraction, Nonlinear optics, Biomedical imaging. Abstract: Supercontinuum generation is observed in highly nonlinear bismuth-oxide fiber with normal dispersion. The small effective area and high nonlinearity allow generation of smooth, spectrally-unstructured spectra from 1300 nm to > 1700 nm with sub-0.5 nJ pulse energies at 1540 nm. |
16,334 | Please write an abstract with title: Inpatient Transportation System Simulation for Porter Work Scheduling Analysis: A Case Study, and key words: Hospitals, Software, Transportation, Computational modeling, Resource management, Context modeling, Data models. Abstract: Special service system to transport inpatients to a health treatment location has been implemented in several countries such as America and South Korea. The problem in transporting patient is an un-even distribution of the workload of porters between shifts and zones. This situation raises a challenge to determine the appropriate number of workers/porters in each shift to ensure an even distribution of workload. The simulation model is built and studied on Flexsim with several steps. Furthermore, several scenarios are carried out by paying attention to workload parameters, by also considering the waiting time experienced by inpatients before being picked up. Workload parameters are defined as the porter's utility and porter's travel distance. There is a correlation between porter's utility and porter's travel distance parameters in the inpatient transportation system. The appropriate scenario that could balance the workload is by allocating more porter in shifts and zones that have more transfer request. This solution balance porter's utility and travel distance and patient's wait time. |
16,335 | Please write an abstract with title: Using histogram correlation to create consistent laser scan maps, and key words: Histograms, Wheelchairs, Sensor systems, Mobile robots, Rotation measurement, Real time systems, Remotely operated vehicles, Hospitals, Error correction, Robotics and automation. Abstract: The paper presents an approach to generate consistent maps in real-time using a laser range sensor. Its application scenario is the Bremen Autonomous Wheelchair "Rolland" that is developed as an autonomous transport vehicle for hospitals. The paper consists of two parts. First, a laser scan matching method is presented that improves an algorithm originally proposed by Weiss et al. (1994) in several aspects. Then, a mapping approach is introduced that is based on the scan matching method. Using a laser scanner mounted on the wheelchair, it generates consistent maps, i.e. maps that do not have discontinuities resulting from the accumulation of errors in the mapping process. As such accumulations cannot be avoided, the resulting errors are corrected whenever the wheelchair returns to areas already mapped An important property of the presented approach is its real-time capability. The mapping is performed on the fly and, thus, the resulting maps can immediately be employed for self-localization. |
16,336 | Please write an abstract with title: IoT-based Predictive Maintenance for Smart Manufacturing Systems, and key words: Industries, Predictive maintenance, Welding, Sensors, Monitoring. Abstract: Manufacturers have been practicing traditional preventive maintenance for many years. However, it is not cost-effective. To avoid ineffective maintenance routine and costs, manufacturers can leverage Industrial IoT and data science. This paper presents a method to optimize the manufacturing processes by using IoT-based predictive maintenance. It illustrates how an IIoT solution can be used to predict a manufacturing defect. The data is collected from multiple smart sensors stored on this welding machine. It is monitored using Statistical process control methods. Machine learning algorithms are applied to reveal hidden correlations in the data sets and detect abnormal data patterns. The recognized data patterns are then reflected in predictive models, classification approaches are used to identify the type of manufacturing processes, namely normal and welding problem. The variables that contribute the most to the failure are identified. |
16,337 | Please write an abstract with title: Considerations for a Distributed GraphBLAS API, and key words: Context, Parallel processing, Libraries, Data structures, Task analysis, Message systems, Electronics packaging. Abstract: The GraphBLAS emerged from an international effort to standardize linear-algebraic building blocks for computing on graphs and graph-structured data. The GraphBLAS is expressed as a C API and has paved the way for multiple implementations. The GraphBLAS C API, however, does not define how distributed-memory parallelism should be handled. This paper reviews various approaches for a GraphBLAS API for distributed computing. This work is guided by our experience with existing distributed memory libraries. Our goal for this paper is to highlight the pros and cons of different approaches rather than to advocate for one particular choice. |
16,338 | Please write an abstract with title: Ultra-wideband Absorber Based on Graphene Metamaterial, and key words: Graphene, Absorption, Metamaterials, Bandwidth, Silicon compounds, Conductivity, Magnetic materials. Abstract: Due to the periodic unit cell, the metamaterial absorber has a wide bandwidth and is easier to achieve perfect absorption characteristics. In this paper, we propose a graphene metamaterial absorber. The unit structure of the absorber is composed of gold as a substrate, silica as a dielectric layer and a portion of the upper surface of the structure coated with graphene. The desired pattern is etched on a single layer of graphene, making it simpler to process. Besides, it can be seen from the simulation results that the graphene metamaterial absorber has an ultra-bandwidth of 7.4 THz, which makes it have wider application valuable in the terahertz band. Large angle absorption characteristics and polarization independence of the absorber further boost its practical application value. According to results of the structural optimization, the thickness of the silicon dioxide layer is set to be 7 µm, and the outer ring and inner ring radius of the pattern on the upper surface of the structure are 2.4 µm and 2.1 µm, respectively. At this time, the bandwidth with absorption rate of the absorber larger than 90% is 3.85 THz. The maximum absorption rate is as high as 99.99% and the absorber actualizes perfect absorption characteristics. The bandwidth of the metamaterial absorber is mainly influenced by the thickness of the dielectric layer. The incident wave on the upper surface of the structure is coherently superimposed with the reflected wave of the metal substrate, and the light wave is converted into other forms of energy so as to achieve the purpose of absorption. The absorber has significant application potential in stealth technology, solar cell conversion and optical switch. |
16,339 | Please write an abstract with title: Power Injection Attacks in Smart Distribution Grids with Photovoltaics, and key words: Photovoltaic systems, Substations, Europe, Benchmark testing, Physical layer, Smart grids, Numerical models. Abstract: In order to protect smart distribution grids from intrusions, it is important to understand possible risks and impacts of attacks. We study the worst-case attack strategy of a power injection attack against the physical layer of a smart distribution grid with a high penetration of photovoltaic resources. We derive both the worst attack signal and worst attack location: The worst attack signal is a step function which switches its sign at the final stage, and the worst attack location is the node with the largest impedance to the grid substation. Numerical examples on a European benchmark model verify the developed results. Finally, both theoretical and numerical results are used to discuss feasible defense strategies against power injection attacks. |
16,340 | Please write an abstract with title: Measurement Errors in Range-Based Localization Algorithms for UAVs: Analysis and Experimentation, and key words: Drones, Global Positioning System, Distance measurement, Measurement errors, Antenna radiation patterns, Antenna measurements, Measurement uncertainty. Abstract: Localizing ground devices (GDs) is an important requirement for a wide variety of applications, such as infrastructure monitoring, precision agriculture, search and rescue operations, to name a few. To this end, unmanned aerial vehicles (UAVs) or drones offer a promising technology due to their flexibility. However, the distance measurements performed using a drone, an integral part of a localization procedure, incur several errors that affect the localization accuracy. In this paper, we provide analytical expressions for the impact of different kinds of measurement errors on the ground distance between the UAV and GDs. We review three range-based and three range-free localization algorithms, identify their source of errors, and analytically derive the error bounds resulting from aggregating multiple inaccurate measurements. We then extend the range-free algorithms for improved accuracy. We validate our theoretical analysis and compare the observed localization error of the algorithms after collecting data from a testbed using ten GDs and one drone, equipped with ultra wide band (UWB) antennas and operating in an open field. Results show that our analysis closely matches with experimental localization errors. Moreover, compared to their original counterparts, the extended range-free algorithms significantly improve the accuracy. |
16,341 | Please write an abstract with title: Wavelet Transform and Machine Learning-Based Biometric Authentication Using EEG Evoked by Invisible Visual Stimuli, and key words: Electroencephalography, Authentication, Visualization, Feature extraction, Wavelet transforms, Time-frequency analysis, Support vector machines. Abstract: In this study, we propose the authentication of individuals using electroencephalograms (EEGs) evoked by the application of invisible visual stimuli. In our previous study, we introduced a wavelet transform, which is a time-frequency analysis method, and applied it to extract features, including time information, to enable more accurate discrimination between individuals. An equal error rate (EER) of 9.4 % was achieved using Euclidean distance matching. In this paper, we introduce a machine learning-based approach in order to further improve the verification performance. An EER of 8.1 % is achieved by the proposed method after training the constituent neural networks using ensemble learning with 30 networks. |
16,342 | Please write an abstract with title: Automation of Program Code Analysis Using Machine Learning Methods, and key words: Codes, Automation, Publishing, Computer bugs, Neural networks, Machine learning, Transformers. Abstract: The paper presents a description of the developed approach and service for analyzing source code in Python. The service allows you to reduce the time spent on the code review process by partially automating this process. After publishing a changeset to a remote Git repository, the service starts checking the changeset and publishes reports of bugs and duplicates found in changeset comment format. A neural network with an original architecture is used for automatic code reviews. PyTorch, Scikit-learn and Transformers libraries are also used. The testing performed did not reveal any errors that affect the operation. All the main functions of the system are performed correctly. |
16,343 | Please write an abstract with title: Generative Feature Replay with Orthogonal Weight Modification for Continual Learning, and key words: Neural networks, Memory, Approximation algorithms, Stability analysis, Data models, Intelligent agents, Task analysis. Abstract: The ability of intelligent agents to learn and remember multiple tasks sequentially is crucial to achieving artificial general intelligence. Many continual learning (CL) methods have been proposed to overcome catastrophic forgetting which results from non i.i.d data in the sequential learning of neural networks. In this paper we focus on class incremental learning, a challenging CL scenario. For this scenario, generative replay is a promising strategy which generates and replays pseudo data for previous tasks to alleviate catastrophic forgetting. However, it is hard to train a generative model continually for relatively complex data. Based on recently proposed orthogonal weight modification (OWM) algorithm which can approximately keep previously learned feature invariant when learning new tasks, we propose to 1) replay penultimate layer feature with a generative model; 2) leverage a self-supervised auxiliary task to further enhance the stability of feature. Empirical results on several datasets show our method always achieves substantial improvement over powerful OWM while conventional generative replay always results in a negative effect. Meanwhile our method beats several strong baselines including one based on real data storage. In addition, we conduct experiments to study why our method is effective. |
16,344 | Please write an abstract with title: Rain Water Harvesting for Smart Water Management Using IoT, and key words: Irrigation, Rain, Program processors, Urban areas, Containers, Rocks, Control systems. Abstract: Rain water harvesting is used to store the rainwater for any future purposes. By incorporating a smart water management system, Rainwater harvesting will gain the ability to store the excess water in a smarter way by utilizing new technology, which deals with the modules like sensors, Arduino processors etc. In this project, the water gets stored in the top of the roof or catchment and later it is brought down through pipes by guttering and stent down process to store in a container. The collected unfiltered water can be used for irrigation and different applications besides of our daily needs like drinking water and livestock. Instead of getting the water dirtied by overflowing of rainwater, it can be stored and used for irrigation and many other purposes like underground rock storage [3]–[6]. By using the different sensors for different applications like water level, distance management, pumping water, filters etc. The proposed model utilizes the rain water in proper way. |
16,345 | Please write an abstract with title: On symbol timing for OFDM based mobile communications systems, and key words: Timing, OFDM, Mobile communication, Wireless LAN, Frequency estimation, Frequency synchronization, Telecommunication standards, Autocorrelation, Digital video broadcasting, Doppler shift. Abstract: This paper deals with symbol timing synchronization issue for broadband OFDM based mobile communication system. A symbol timing approach using adaptive threshold is proposed. Several OFDM training symbol formats and the corresponding timing metrics are evaluated. Simulations am carried out using Rayleigh fading model at 5 GHz band, with the velocity being 100 km/h and 150 km/h. The performances of the simulation results demonstrate that the proposed symbol timing method is feasible for mobile telecommunications. |
16,346 | Please write an abstract with title: Automation of Crude Oil Distillation in a Rectification Column, and key words: Temperature measurement, Automation, Transducers, Oils, Distillation equipment, Refining, Process control. Abstract: In order to optimize the control system and reduce the impact on the environment, an automated control system has been developed for the technological process of primary oil refining in the distillation column. The tasks of installing process control tools, improving the reliability of the emergency protection system, expanding the functions of automatic and automated control and management, improving the quality of process control, and improving the quality of the analysis of the facility’s operation were solved. Brief theoretical information about the process of atmospheric distillation of oil with its single evaporation using a distillation column is given. An analysis of the thermal and material balance of the mass transfer process in the distillation column was made. Equations of dynamics and statics are obtained, which determine a number of features for the heat balance in the vapor phase. The technological mode of parameters of the mass transfer process has been developed. The composition and necessary information support of the oil refining control system have been determined. The processes of collecting and transmitting information from the flow, pressure and temperature transducers installed on the measuring lines of the metering units of the production site are described. Based on the optimization carried out, a SCADA system and a mnemonic diagram for controlling a distillation column in the Trace Mode 6 package were developed, which provides information output to the operator’s automated workplace. |
16,347 | Please write an abstract with title: Coupled-field thermal analysis of high-speed permanent magnetic generator applied in micro-turbine generator, and key words: Couplings, Magnetic analysis, Magnetic flux, Computational fluid dynamics, Thermal stability, Magnetohydrodynamics, Cooling, Temperature distribution, Stators, Steady-state. Abstract: This paper presents a kind of investigative method with thermal stability of high-speed permanent magnetic generator through a simplified model employing a air-cooling system. Given the certain circumstance, the losses and air flux is known, it is easy to estimate the heat rate took away by the cooling air, and easy to obtain the temperature distribution of the stator at a steady-state. Using computational fluid dynamics (CFD) soft package embedded in Ansys/sup /spl reg// software, the author gives the simulation of the problem, and some important conclusions are achieved as well. |
16,348 | Please write an abstract with title: Ultracapacitors modeling improvement using an experimental characterization based on step and frequency responses, and key words: Supercapacitors, Frequency, Circuit testing, Electrochemical impedance spectroscopy, Capacitors, Hybrid electric vehicles, Circuit simulation, Conductors, Electrodes, Resistors. Abstract: This paper deals with ultracapacitors modeling that has been improved for high power source purpose such as in hybrid and electric vehicles applications. An experimental method based on the combination of step and frequency response has been implemented and used in a dedicated test bench. First, a critical overview of available ultracapacitors models is made and a new approach is proposed. Then, after constant current and impedance spectroscopy tests, the experimental results are presented and discussed. Finally, the exploitation of the tests results leads to the identification of a proposed model parameters. This electric circuit is validated by comparing simulation to experimental curves. |
16,349 | Please write an abstract with title: Focal Triplet Loss for Multi-Object Tracking, and key words: Training, Measurement, Target tracking, Computational modeling, Detectors, Feature extraction, Computers and information processing. Abstract: Modern multi-object tracking methods tend to focus on similarity metrics for instances. Existing methods adopt the mainstream triplet loss to help deep networks learn instance similarity. However, triplet loss easily ignores samples with abnormal similarity and difficult samples; thus, the networks have limited ability to extract object features for similarity calculation. In this paper, we propose a novel focal triplet loss (FTL) to solve such problems. FTL pays considerable attention to objects of the same ID with low similarity and different IDs with high similarity. In addition, FTL can assign additional reasonable loss weights to difficult samples, making the networks extract more discriminative feature embeddings to calculate instance similarity and improve tracking accuracy. We also propose a new joint detection and embedding model integrating a detector and an embedding model into a single network. Results show that our method achieves state-of-the-art performance, specifically MOTA of 87.28% on the KITTI dataset. |
16,350 | Please write an abstract with title: ECG frequency domain features extraction: a new characteristic for arrhythmias classification, and key words: Electrocardiography, Frequency domain analysis, Feature extraction, Analysis of variance, Databases, Fibrillation, Statistical analysis, Signal processing algorithms, Application software, Rhythm. Abstract: This article describes a new ECG spectrum feature that allows the classification of dangerous arrhythmia. In order to check the classification effectiveness of this variable, the statistical method known as ANOVA has been used. The results obtained show that this parameter could be an effective classification feature of dangerous arrhythmia with an approximated probability of error of 0.00%. |
16,351 | Please write an abstract with title: DyCo3D: Robust Instance Segmentation of 3D Point Clouds through Dynamic Convolution, and key words: Convolutional codes, Three-dimensional displays, Convolution, Semantics, Refining, Pipelines, Transformers. Abstract: Previous top-performing approaches for point cloud in-stance segmentation involve a bottom-up strategy, which often includes inefficient operations or complex pipelines, such as grouping over-segmented components, introducing additional steps for refining, or designing complicated loss functions. The inevitable variation in the instance scales can lead bottom-up methods to become particularly sensitive to hyper-parameter values. To this end, we propose in-stead a dynamic, proposal-free, data-driven approach that generates the appropriate convolution kernels to apply in response to the nature of the instances. To make the kernels discriminative, we explore a large context by gathering homogeneous points that share identical semantic categories and have close votes for the geometric centroids. Instances are then decoded by several simple convolutional layers. Due to the limited receptive field introduced by the sparse convolution, a small light-weight transformer is also devised to capture the long-range dependencies and high-level interactions among point samples. The proposed method achieves promising results on both ScanetNetV2 and S3DIS, and this performance is robust to the particular hyper-parameter values chosen. It also improves inference speed by more than 25% over the current state-of-the-art. Code is available at: https://git.io/DyCo3D |
16,352 | Please write an abstract with title: Identification of long-term scenarios of electricity network development, and key words: Power generation, Character generation, Power system economics, Power generation economics, Economic forecasting, Environmental economics, Fuel economy, Uncertainty, Electricity supply industry, Fossil fuels. Abstract: This paper describes a process for generating scenarios of future electricity network development, and of technologies which might be applied in the electricity supply industry under different future circumstances. The process begins by considering scenarios at the most distant timeframe desired, and then working backwards to identify a set of shorter-term scenarios which interpolate between the long-term picture and current circumstances and trends. The paper discusses important factors which are taken into account in the initial long-term scenario generation, and in the identification of their corresponding shorter-term counterparts. The process is illustrated using its results in generating sets of scenarios, addressing the years 2020 and 2050, of future development of the electricity system in Great Britain. Examples of the resulting medium and long-term scenarios are described and illustrated pictorially |
16,353 | Please write an abstract with title: Gird-Forming Distributed Generation Inverter Control for A Smooth Transition from Grid-Connected to Islanded Operation Mode in Microgrids, and key words: Reactive power, Simulation, Microgrids, Power system stability, Stability analysis, Inverters, Hardware. Abstract: One of attractive features of microgrids (MGs) is their capability to meet the local load demands uninterruptedly even during islanding events. To realize a smooth transition from the grid-connected (GC) operation mode to islanded (IS) mode in MGs, two different grid-forming control strategies, featuring stability enhanced grid-support functionalities, were proposed in this paper for grid-tied inverters (GTIs) of distributed generations (DGs). With proposed controls, GTIs are able to ride through IS events with very slight fluctuations as well as regulate the MG frequency and voltage under IS mode. The corresponding MG operation mode transition behaviors were studied and compared under a high penetration from inverter-interfaced DGs, including a flexible combined heat and power (F-CHP) cogeneration plant and a photovoltaic (PV) generation plant. Simulation results based on a 13-bus test feeder in the MATLAB-Simulink platform are provided to verify the effectiveness of the proposed control paradigms. Also, a simplified hardware testbed with modular power converters was implemented, experimental results under different operating scenarios are presented for validation purposes. |
16,354 | Please write an abstract with title: Efficient Identification of Acoustic Linear Systems, and key words: Linear systems, Wiener filters, Echo cancellers, Estimation, Acoustics, Matrix decomposition, Iterative methods. Abstract: The identification of acoustic linear systems is a critical issue in numerous applications related to acoustic en-vironments. A major difficulty that arises in this context is the long length of impulse responses. In this paper, we present an efficient method to address this issue, using the nearest Kronecker product decomposition of the impulse response, along with low-rank approximations, which can be further improved by using a proper permutation matrix. As a result, we develop an iterative Wiener filter using this method, with superior performances with respect to the conventional Wiener filter, especially in the case with small amount of data available for the estimation of the required statistics. Simulations performed in the context of stereophonic acoustic echo cancellation support the advantages of the proposed solution. |
16,355 | Please write an abstract with title: Reconstruction and Upscaling of 3D Models from Single or Multiple Views, and key words: Solid modeling, Three-dimensional displays, Image resolution, Computational modeling, Conferences, Feature extraction, Data engineering. Abstract: In recent years research related to 3D reconstruction from 2D images has gained traction and several approaches have been introduced. However, most conventional methods for 3D reconstruction are time consuming and tedious. Additionally, they produce low resolution results and have their own limitations. Our approach attempts to resolve these limitations by using a modified encoder-decoder architecture which generates a low resolution 3D coarse volume from a set of 2D images of an object. In order to improve the quality of the generated model, a pseudo high resolution 3D volume is generated by upsampling the low resolution volume which has multiple missing features. Parallelly, RGB-D images from different angles are generated using the Blender software. Furthermore, these RGB-D images are upscaled to high resolution images using a CNN-image upscaler and a depth map is extracted. These newly generated depth values assist in identifying the missing features from the pseudo 3D volume thereby generating a final high quality 3D coarse volume. Our results show that this approach outperforms the existing methods. |
16,356 | Please write an abstract with title: Optimising the selection of samples for robust lidar camera calibration, and key words: Measurement, Laser radar, Codes, Conferences, Pipelines, Estimation, Software. Abstract: We propose a robust calibration pipeline that optimises the selection of calibration samples for the estimation of calibration parameters that fit the entire scene. We minimise user error by automating the data selection process according to a metric, called Variability of Quality (VOQ) that gives a score to each calibration set of samples. We show that this VOQ score is correlated with the estimated calibration parameter's ability to generalise well to the entire scene, thereby overcoming the overfitting problems of existing calibration algorithms. Our approach has the benefits of simplifying the calibration process for practitioners of any calibration expertise level and providing an objective measure of the quality for our calibration pipeline's input and output data. We additionally use a novel method of assessing the accuracy of the calibration parameters. It involves computing reprojection errors for the entire scene to ensure that the parameters are well fitted to all features in the scene. Our proposed calibration pipeline takes 90s, and obtains an average reprojection error of 1-1.2cm, with standard deviation of 0.4-0.5cm over 46 poses evenly distributed in a scene. This process has been validated by experimentation on a high resolution, software definable lidar, Baraja Spectrum-Scan™; and a low, fixed resolution lidar, Velodyne VLP-16. We have shown that despite the vast differences in lidar technologies, our proposed approach manages to estimate robust calibration parameters for both. Our code and data set used for this paper are made available at https://github.com/acfr/cam_lidar_calibration. |
16,357 | Please write an abstract with title: A generalized window approach to spectral estimation, and key words: Autocorrelation, Stochastic processes, Entropy, Meteorology, Signal analysis, Mean square error methods, Convolution, Telecommunications, Convergence. Abstract: An approach to spectral estimation is developed. The estimator is constructed from only two starting requirements: closeness to an original autocorrelation estimate and planarity, i.e., smoothness, of the corresponding spectral estimator. The inverse of the variance of the original autocorrelation estimate enters as a weight. By making various a priori assumptions about the variance, and by selecting two mathematical formulations of the planarity requirement, both the classical window and the maximum entropy methods result as special cases. Thus, the two methods are put together since they follow from the same starting requirements. Attention is given to the case where both the variance is estimated in terms of the original autocorrelation estimate, and planarity is forced by the minimization of a functional involving the absolute value of the power spectrum derivatives. A window method results but with a variance dependent window involving two parameters, the order of the derivative and a parameter equivalent to the window width. An application to a meteorological process is included as an illustration. |
16,358 | Please write an abstract with title: ICEBIN: Image Contrast Enhancement Based on Induced Norm and Local Patch Approaches, and key words: Lighting, Reflectivity, Histograms, Image color analysis, Image enhancement, Dynamic range, Retina. Abstract: Traditional histogram equalization may cause degraded results of over-enhanced images under uneven illuminations. In this paper, a simple and effective image contrast enhancement method is proposed to achieve high dynamic range imaging. First, the illumination of each pixel is estimated by using an induced norm of a patch of the image. Second, a pre-gamma correction is proposed to enhance the contrast of the illumination component appropriately. The parameters of gamma correction are set dynamically based on the local patch of the image. Third, an automatic Contrast-Limited Adaptive Histogram Equalization (CLAHE) whose clip point is automatically set is applied to the processed image for further image contrast enhancement. Fourth, a noise reduction algorithm based on the local patch is developed to reduce image noise and increase image quality. Finally, a post-gamma correction is applied to slightly enhance the dark regions of images and not affect the brighter areas. Experimental results show that the proposed method has its superiority over several state-of-the-art enhancement quality techniques by using qualitative and quantitative evaluations. |
16,359 | Please write an abstract with title: Fuzzy adaptation two-degrees-of-freedom PID control, and key words: Fuzzy control, Three-term control, Automatic control, Fuzzy logic, Machinery, Robust control, Automation. Abstract: This paper presents a method of fuzzy adaptation two-degrees-of-freedom PID control which combines fuzzy logic control with two-degrees-of-freedom PID control. The simulation results show that this new method can suppress the effect of parameter variations and obtain good dynamic responses in both command tracking characteristic and disturbance rejection. |
16,360 | Please write an abstract with title: Micromagnetic simulation of finite and infinite-size Fe nanowire arrays, and key words: Geometry, Anisotropic magnetoresistance, Shape, Magnetization, Wires, Magnetic hysteresis, Raw materials. Abstract: The article presents some results of ICPE-CA research for the development of new permanent magnets based on nano ferromagnetic wires without rare earths or other expensive raw materials. The paper presents the results of the modeling of some spatial arrangements of the iron nanowires. Several ratios between the base area and the length of the wire are considered. Hysteresis loops show how the properties of the entire configuration are influenced depending on the geometry of the nanowires and their arrangement. The micromagnetism model started from the definition of the types of energies that compete with each other and that define the magnetic properties. The simulations show that for nanowires with aspect ratio L/ℓ ≥ 10 they can be treated as infinitely long nanowires. Study of finite and infinite-size arrays of nanowires shows that the hysteresis loops converge to an oblique shaped loop with coercive field larger than 100 kA/m. |
16,361 | Please write an abstract with title: State Space Disturbance Observer Considering Residual Disturbance, and key words: Asymptotic stability, Mathematical model, Estimation, Stability analysis, Estimation error, Control systems, Robust control. Abstract: This paper presents a novel disturbance observer (DOB) for overcoming the limitation of uniformly bounded stability in existing DOB-based control systems and to attain asymptotic stability. The DOB is derived by considering the residual disturbance remaining after disturbance decoupling is performed. It focuses on the elimination of the residual disturbance as well as minimization of the estimation error. By considering the system state and the residual disturbance simultaneously in a Lyapunov stability function, the proposed DOB cancels the residual disturbance term and attains asymptotic stability. In contrast, existing DOBs consider these factors separately in different Lyapunov functions. A basic novel DOB is initially derived for achieving asymptotic stability and is later combined with the existing DOB. This forms a novel extended DOB that achieves a better estimation rate and better performance with regard to DOB-based control than those of existing DOBs. |
16,362 | Please write an abstract with title: Analysis and optimization of the picking up medicine queuing system for a medical warehouse - a case study of Shenzhen Jianhua Medical Company, and key words: Queueing analysis, Computer aided software engineering, Performance analysis, Marketing and sales, Companies, Hospitals, Cities and towns, Costs, Counting circuits, Telephony. Abstract: This paper, based on the warehouse operations of Shenzhen Jianhua Medical company, describes the elements of the picking up medicine queueing system, identifies the characteristics of the probability distribution of customer interarrival times and service times, determines which queueing model is most appropriate for the Jianhua company, applies M/Ms model and M/M/s nonpreemptive priorities model to obtain the key measures of performance for this queueing system, applies economic analysis to decide how many servers should be provided to minimize the total cost, and gives the optimal design to improve the behavior of the warehouse operations for Jianhua Company. |
16,363 | Please write an abstract with title: CW ruby laser pumped by an argon ion laser, and key words: Pump lasers, Laser excitation, Argon, Laser noise, Acoustic beams, Laser beams, Power lasers, Mirrors, Amplitude modulation, Reflectivity. Abstract: A simple CW ruby laser pumped by a 514.5-nm argon ion laser, utilizing an uncoated ruby rod (no external mirrors), is described. The output does not exhibit spiking, but does show a low amplitude ∼1 percent) of modulation. |
16,364 | Please write an abstract with title: Timing optimization of nested loops considering code size for DSP applications, and key words: Timing, Digital signal processing, Pipeline processing, Parallel processing, Application software, Embedded software, Embedded system, Software performance, Multidimensional systems, Software algorithms. Abstract: Software pipelining for nested loops remains a challenging problem for embedded system design. The existing software pipelining techniques for single loops can only explore the parallelism of the innermost loop, so the final timing performance is inferior. While multidimensional (MD) retiming can explore the outer loop parallelism, it introduces large overheads in loop index generation and code size due to transformation. We use MD retiming to model the software pipelining problem of nested loops. We show that the computation time and code size of a software-pipelined loop nest is affected by execution sequence and retiming function. The algorithm of software pipelining for nested loops technique (SPINE) is proposed to generate fully parallelized loops efficiently with the overheads as small as possible. The experimental results show that our technique outperforms both the standard software pipelining and MD retiming significantly. |
16,365 | Please write an abstract with title: Performance Evaluation and Field Test of Automatic Voltage Control System for a Wind Farm, and key words: Reactive power, Voltage fluctuations, Wind farms, Power system stability, Automatic voltage control, Regulation, Wind turbines. Abstract: As the capacity of the wind farm is being increasing, the grid-connected stability problems caused by reactive power and voltage fluctuation cannot be ignored, one effective solution is to adopt the automatic voltage control system (AVCS) in the wind farm. This paper briefly describes the structure and control strategy of AVCS, and introduces an operation scheme for AVCS including the voltage control and reactive power regulation principles. Especially, communication modes of AVCS are introduced. The proposed operation scheme can regulate the voltage of the bus within the scope of dispatching requirements in the wind farm. Also, it can flexibly coordinate the output reactive power of every wind turbine generator and reactive power compensation device in the wind farm. Finally, this paper evaluates the control effect and dynamic response characteristic of the AVCS by the field test, the effectiveness of the proposed operation scheme is verified. |
16,366 | Please write an abstract with title: New class of impulsive noise reduction filters based on kernel density estimation, and key words: Noise reduction, Filters, Kernel, Colored noise, Color, Histograms, Filtering, Probability density function, Shape, Multidimensional systems. Abstract: The paper presents a new filtering scheme for the removal of impulsive noise in color images. It is based on estimating the probability density function for color pixels in a filter window by means of the kernel density estimation method. A quantitative comparison of the proposed filter with the vector median filter shows its excellent ability to reduce noise while simultaneously preserving fine image details. |
16,367 | Please write an abstract with title: Safety Assured Online Guidance With Airborne Separation for Urban Air Mobility Operations in Uncertain Environments, and key words: Aircraft, Uncertainty, Safety, Trajectory, Heuristic algorithms, Multi-agent systems, Aerospace control. Abstract: The concept of Urban Air Mobility (UAM) proposes to use revolutionary new electrical vertical takeoff and landing (eVTOL) aircraft to provide efficient and on-demand air transportation service between places previously underserved by the current aviation market. A key challenge for the success of UAM is how to manage large-scale autonomous flight operations with safety guarantee in high-density, dynamic and uncertain airspace environments. In this paper, a safety assured decentralized online guidance algorithm with airborne self-separation capability is proposed and analyzed for multi-aircraft autonomous flight operations under uncertainties. The problem is formulated as a multi-agent Markov Decision Process with continuous action space and is solved by a customized decentralized online algorithm based on Monte Carlo Tree Search (MCTS). To guarantee the safety of real-time autonomous flight operations in uncertain environments, the formulation of loss of chance constrained separation is introduced and integrated with the proposed MCTS algorithm. In addition, Gaussian process regression along with Bayesian optimization is employed to discretize the continuous action space, which helps shorten the flight time. A comprehensive numerical study shows that the proposed algorithm can provide safe onboard guidance with guaranteed low near mid-air collision probability in uncertain and high-density airspace environments. |
16,368 | Please write an abstract with title: Using Q-Learning to Personalize Pedagogical Policies for Addition Problems, and key words: COVID-19, Q-learning, Education, Machine learning, Signal processing, Markov processes, Standards. Abstract: The prevalence of COVID-19 has illuminated the need for practical digital education tools over the past year. With students studying from home, teachers have struggled to provide their students with adequately challenging coursework. Our project aims to solve this issue in the context of math. More specifically, our goal is to encourage thoughtful learning by supplying students with personalized two-number addition problems that take time to solve but expect the student to answer correctly still. Our solution is to model the process of selecting a math problem to give a student as a Markov Decision Process (MDP) and then use Q-learning to determine the best policy for arriving at the most optimally challenging two-number addition problem for that student. The project creates three student simulators based on group member data. We show that it took student one: $(162 \pm 134)$ iterations to give appropriate level problems where the first entry is mean and the second is the standard deviation. Student two took $(230 \pm 205)$ iterations, and student three took $(247 \pm 236)$ iterations. Lastly, we demonstrate that pre-training our model on students two and three and testing on student one showed a significant improvement from $(162 \pm 134)$ iterations to $(35 \pm 44)$ iterations. |
16,369 | Please write an abstract with title: Control of a centrifugal pump as a turbine in an energy recovery system, and key words: Meters, Reactive power, Delays, Prototypes, Mathematical model, Tools, Internet of Things. Abstract: In this paper, the control of an energy recovery system is analyzed. The energy recovery system is built with a pump working as a turbine (PAT), an asynchronous generator, and a four-quadrants converter that connects the system to the electrical network. This system regulates the water pressure at the output of the PAT and, because of the drop in pressure, it injects the recovered energy in the electrical grid. Furthermore, a controller is designed for the system shaping the dynamic response of the system using a Bessel polynomial and practical considerations. The design of the controller is validated through simulations. |
16,370 | Please write an abstract with title: Root-Cause Analysis with Interactive Decision Trees, and key words: Prototypes, Software, Pattern recognition, Manufacturing, Decision trees, Quality management, Automotive engineering. Abstract: When manufacturing products fail, root-cause analysis is essential to improve the affected products and processes. However, finding the relevant influences among numerous possible factors can be a challenge. Computer-aided methods for anomaly detection and pattern recognition can significantly speed up this process to provide great benefits in quality management applications. We introduce a method for root-cause analysis employing interactive decision trees. Improving upon an existing concept, we developed a software prototype that utilizes a lean yet powerful representation of relationships and influences. Several interactive options allow quality data analysts to integrate their expert domain knowledge into the pattern recognition process and quickly identify anomalies among the product attributes of defective vehicles. |
16,371 | Please write an abstract with title: Hamming Distance Encoding Multihop Relation Knowledge Graph Completion, and key words: Tensors, Hamming distance, Computational modeling, Task analysis, Encoding, Data models, Data mining. Abstract: Knowledge graphs (KGs) play an important role in many real-world applications like information retrieval, question answering, relation extraction, etc. To reveal implicit knowledge from a knowledge graph (KG), viz. knowledge graph completion (KGC), is a crucial task for the downstream applications based on KG. For this purpose various embedding-based approaches have been proposed recently. This paper proposes a new approach named HRESCAL to KGC. It extends the well-known embedding-based approach RESCAL by introducing Hamming distance-based encoder to capture implicit multihop and partial inverse relation features in a KG. Experimental results on widely used KGC benchmarks show that the new approach achieves state-of-the-art or is competitive AUC performance. |
16,372 | Please write an abstract with title: Android based Optimization and Queue System at Passenger Vessel Services Crossings, and key words: Queue, tickets, ferry, Android, waiting time. Abstract: Samosir is one of the islands surrounded by the largest lake (lake Toba) in Indonesia. To connect Samosir Island with other areas outside the Samosir Island, a ferry is needed. However, at every peak holiday season the queue of vehicles to and from Samosir Island is very high. This study aims to design and develop an Android-based queue application that can be downloaded at every smartphone application store. By using the built-in application, passengers can order tickets online so there will be no need to queue. Passengers only need to go to the counter until when the queue number is available. Simulation results show that passengers only need an average waiting time of less than one hour compared to conventional about more than 12 hours. |
16,373 | Please write an abstract with title: Research on Human Action Recognition Based on Improved Pooling Algorithm, and key words: Stochastic pooling, Dropout, Model average, 3DCNN. Abstract: With the rapid development of deep learning, human behavior recognition has become a focus of research. When using various artificial neural network training models to recognize human behavior, the problem of overfitting has always been a difficult point that hinders the improvement of the accuracy of recognition. This paper combines stochastic pooling and Dropout, proposes an improved stochastic pooling method based on Dropout, and applies it to a 3D convolutional neural network for human behavior recognition to solve the problem of overfitting. In the training phase, the Dropout method is introduced into the pooling layer of the 3DCNN, and the unit values of the pooling layer are randomly suppressed, so that more sub-models are generated on the pooling layer. During the testing phase, the idea of double probability weighting method is introduced The idea of combining the weight of the activation value of the selected neuron and the activation value of the selected neuron is introduced to obtain an approximate model of all sub-models. Finally, the trained model was input into the UCF101 data set for verification, and an accuracy rate of 70.09% was obtained. Experimental results show that this method can extract more general features, enhance generalization ability, effectively suppress overfitting, and improve accuracy. |
16,374 | Please write an abstract with title: Controllable Image Restoration for Under-Display Camera in Smartphones, and key words: Degradation, Cameras, Optical imaging, Image restoration, Optical reflection, Optical noise, Kernel. Abstract: Under-display camera (UDC) technology is essential for full-screen display in smartphones and is achieved by removing the concept of drilling holes on display. However, this causes inevitable image degradation in the form of spatially variant blur and noise because of the opaque display in front of the camera. To address spatially variant blur and noise in UDC images, we propose a novel controllable image restoration algorithm utilizing pixel-wise UDC-specific kernel representation and a noise estimator. The kernel representation is derived from an elaborate optical model that reflects the effect of both normal and oblique light incidence. Also, noise-adaptive learning is introduced to control noise levels, which can be utilized to provide optimal results depending on the user preferences. The experiments showed that the proposed method achieved superior quantitative performance as well as higher perceptual quality on both a real-world dataset and a monitor-based aligned dataset compared to conventional image restoration algorithms. |
16,375 | Please write an abstract with title: Investigating Echo State Network Performance with Biologically-Inspired Hierarchical Network Structure, and key words: Network topology, Sociology, Neural networks, Standards organizations, Training data, Stochastic processes, Organizations. Abstract: The nervous systems of animals exhibit complex recurrent topologies. These networks often show key properties like small-worldness and clustering, forming a complex hierarchical topology that is very different from many standard random graphs. Current machine learning techniques are dominated by feed-forward networks without recurrent connectivity, or specialized architectures for gated recurrent connectivity (such as Long-Short Term Memory Networks). Reservoir computing networks, such as echo state networks, represent an exciting alternative form of recurrent networks, which require limited training data compared to other recurrent networks. Echo state networks, however, typically use randomized network topologies. We introduce a novel reservoir computing network, with a hierarchical network structure inspired by organization of biological networks, utilizing hierarchical stochastic block models. We demonstrate the use of this network for predicting dynamic system evolution, and we compare this network to existing echo state network topologies. We find that the best performing networks utilize our new topology, and, for Mackey-Glass system prediction as well as MNIST classification, the overall distribution of solutions is improved. For the Mackey-Glass system, the median population NRMSE improved from 0.856 to 0.08, and for MNIST the median population accuracy increased from 92.5% to 96.8%. This may be preliminary indication of improving network function through changing network topology. The spectral radii of the produced HSBM topologies do not always obey the echo state property, and we show that both the spectral radius as well as common graph metrics do not predict the best performing networks. This argues for further investigation into the structural properties of high performing networks utilizing reservoir computing. |
16,376 | Please write an abstract with title: The Web Challenges in the Training Process – The humansoft Case Study, and key words: Training, Customer satisfaction, Companies, User experience, Task analysis, Standards, Interoperability. Abstract: The constant evolution of web technologies has led to the appearance of platforms that ease the management of users' tasks today. To maximize customer satisfaction and provide solutions according to current market standards, companies must adapt their products, with a particular focus on web-based solutions, considering the increase of the user experience. In this way, this paper presents a web development real case study, in the humansoft company, where several modules were developed related to the two main products of the company, namely, humantrain, which is a system for managing the training process, and humanportal, which is a web application that allows the interoperability among humantrain and the web. Both applications allow training providers and/or companies to profit from the management of their resources, both at a pedagogical and financial level. |
16,377 | Please write an abstract with title: Optimal Antenna Array Pattern Synthesis via Hybrid Optimization, and key words: Continuous wavelet transforms, Digital TV, Lead, Gold. Abstract: The synthesis of a shaped beams by means of given fixed-geometry arrays is a canonical open problem relevant in many engineering areas. In fact, several approaches have been proposed for optimizing as much as possible some performance parameters or the dimensions of the arrays, but they all suffer from several drawbacks which are effectively tackled by the proposed approach. In this contribution, we propose an innovative approach to the mask-constrained power synthesis of shaped beams through fixed-geometry antenna arrays having whatever layout and element patterns. In particular, we are able to formulate the problem as the global optimization of a very small number of parameters, and we propose and discuss two different solution procedures. |
16,378 | Please write an abstract with title: Cyclicity and controlability in linear time-invariant systems, and key words: Control systems, Polynomials, Controllability, Observability, System testing, Vectors. Abstract: A number of results, involving the notions of controllability (observability) and cyclicity in a linear time-invariant control system, are derived using a new basic theorem. New tests of cyclicity and controllability (observabllity), together with new algorithms to evaluate the controllable (observable) modes and the minimal polynomial are also presented. |
16,379 | Please write an abstract with title: MiniDelay: Multi-Strategy Timing-Aware Layer Assignment for Advanced Technology Nodes, and key words: Wires, Delays, Routing, Couplings, Two dimensional displays, Metals. Abstract: Layer assignment, a major step in global routing of integrated circuits, is usually performed to assign segments of nets to multiple layers. Besides the traditional optimization goals such as overflow and via count, interconnect delay plays an important role in determining chip performance and has been attracting much attention in recent years. Accordingly, in this paper, we propose MiniDelay, a timing-aware layer assignment algorithm to minimize delay for advanced technology nodes, taking both wire congestion and coupling effect into account. MiniDelay consists of the following three key techniques: 1) a non-default-rule routing technique is adopted to reduce the delay of timing critical nets, 2) an effective congestion assessment method is proposed to optimize delay of nets and via count simultaneously, and 3) a net scalpel technique is proposed to further reduce the maximum delay of nets, so that the chip performance can be improved in a global manner. Experimental results on multiple benchmarks confirm that the proposed algorithm leads to lower delay and few vias, while achieving the best solution quality among the existing algorithms with the shortest runtime. |
16,380 | Please write an abstract with title: A lightweight multi-session synchronous multimedia collaborative environment, and key words: Collaboration, Collaborative software, Java, Multimedia systems, Information technology, Software design, Collaborative work, Application software, Delay, Network servers. Abstract: Summary form only given. We present a software framework designed to provide transparent latecomer support and session recorder to a synchronous collaboration environment written in Java. The objective of this work is to develop a generic framework that can be easily integrated into other similar systems. The system supports not only Java applications and applets, but also Java media framework player allowing sharing of multimedia applications in a transparent way. In the meantime, we developed client synchronization for the system in order to minimize the network transmission latency and let all the clients see the same view of the shared application at the same time. In our design, we add a session recorder to the system. The collaboration server is responsible for recording events while clients send events to others through it. |
16,381 | Please write an abstract with title: AgGa/sub 1-x/In/sub x/Se/sub 2/ nonlinear crystals for noncritical phase matching processes, and key words: Crystallization, Solids, Chemicals, Temperature, Phase measurement, Wavelength measurement, Optical harmonic generation, Optical frequency conversion, Anisotropic magnetoresistance, Nonlinear optics. Abstract: Main problem while growing solid solution crystals consists in obtaining samples, which are homogeneous in chemical composition. In order to reduce chemical heterogeneity during crystallization of a solid solution in the AgGaSe/sub 2/-AgInSe/sub 2/ system, we made experiments in re-crystallization of an equilibrium solid phase with melt equilibrium with this phase under an insignificant temperature differential. Composition of the crystal being grown and the melt as well as crystallization temperature were determined according to a connode. In order to establish said correlation, we grew solid solution AgGa/sub 1-x/In/sub x/Se/sub 2/ crystals. On the elements cut from these crystals, we measured both wavelength of the second harmonic generation of the oo-e type with noncritical phase matching and wavelength of the anisotropy. SHG with nonlinear phase matching for different AgGa/sub 1-x/In/sub x/Se/sub 2/ elements was measured at working wavelengths 9.66, 10.18 and 10.72 /spl mu/m. More comprehensive investigations were performed on an AgGa/sub 1-x/In/sub x/Se/sub 2/ sample with x=0.25 concerning determination of its optical characteristics. |
16,382 | Please write an abstract with title: Pattern Sensing Based Digital Predistortion of RF Power Amplifiers under Dynamical Signal Transmission, and key words: Sensors, Predistortion, Radio frequency, 5G mobile communication, Indexes, Table lookup, Real-time systems. Abstract: In this paper, a pattern sensing based digital predistortion (DPD) technique for radio frequency (RF) power amplifiers (PAs) under dynamical signal transmission is proposed. Unlike conventional methods where real time re-calibration is required, this approach utilizes a low resolution amplitude-modulation to amplitude-modulation (AM/AM) pattern to sense PA characteristics and then quickly select proper DPD coefficients to linearize the PA. Experimental results show that the proposed method can provide an efficient a nd effective w ay to deal with complex dynamic signal transmission scenarios and maintain very good linearization performance, which is very suitable for future 5G applications. |
16,383 | Please write an abstract with title: A Kalman filter-based radar track data fusion algorithm applied to a select ICBM case, and key words: Radar tracking, Kalman filters, Computer aided software engineering, Radar measurements, Trajectory, Missiles, Sensor arrays, Computational modeling, Analytical models, Fusion power generation. Abstract: A Kalman filter-based approach for fusing track data from two separate phased array radar sensors is developed and applied to a select ICBM case to demonstrate the potential enhancement of position and velocity estimates over a single radar. When compared to a theoretical assessment based on steady state filter performance, the Kalman filter approach yielded performance enhancements within 7% of theoretical prediction. The theoretical assessment indicated a 33% improvement in position accuracy and a 29% improvement in velocity accuracy for an assumed bias error in both radars. The simulation yielded a 29% improvement in position accuracy and a 22% improvement in velocity accuracy with the same bias assumption. The improvement was computed relative to the radar with twice the beamwidth and the same sensitivity as the second "fused" radar. The two radars were assumed to be collocated at the terminal area of ICBM flight. |
16,384 | Please write an abstract with title: UAVs as an Intelligent Service: Boosting Edge Intelligence for Air-Ground Integrated Networks, and key words: Wireless communication, Training, 6G mobile communication, Computational modeling, Atmospheric modeling, Computer architecture, Unmanned aerial vehicles. Abstract: The air-ground integrated network is a key component of future sixth generation (6G) networks to support seamless and near-instant super-connectivity. There is a pressing need to intelligently provision various services in 6G networks, which is challenging. To meet this need, in this article, we propose a novel architecture called UaalS, that is, unmanned aerial vehicles (UAVs) as a intelligent service for the air-ground integrated network, featuring the UAV as a key enabler to boost edge intelligence with the help of machine learning (ML) techniques. We envision that the proposed UaalS architecture could intelligently provision wireless communication service, edge computing service, and edge caching service by a network of UAVs, making full use of UAVs' flexible deployment and diverse ML techniques. We also conduct a case study where UAVs participate in the model training of distributed ML among multiple terrestrial users, whose result shows that the model training is efficient with low energy consumption of UAVs. Finally, we discuss the challenges and some open research issues in UaaIS. |
16,385 | Please write an abstract with title: Ant Colony Optimization with Simulated Annealing Algorithm for Google Maps, and key words: Ant Colong Optimzation, Heuristic, Particle Swarm optimziation, Simulated Anneling algorithm, localization, Cost Value, Hill Climbing, Global Minima. Abstract: In the article that is being suggested, a brandnew, sophisticated route optimization is created using cuttingedge software that makes use of Google APIs and unsupervised machine learning. Since Google Maps and its API have improved recently, outmoded solutions have been decommissioned. Therefore, route optimization is carried out in this study using a heuristic method by merging three approaches, including ant colony optimization (ACO), simulated annealing algorithm (SA), and updated Google APIs. Along with executing route optimization, these three techniques-based ACO-SA-Google Maps (ASG) API will be contrasted with other approaches including genetic algorithms, K-means clustering, particle swarm optimization (PSO), etc. to assess performance, cost, and carbon emissions. The demand for home delivery, travel, and other necessities is increasing as a result of population increase and a developing technology lifestyle, necessitating the use of contemporary equipment by the average person. To increase performance, the ASG technique will develop route optimization using a modernized methodology. Route optimization eventually aims to be used in a variety of contexts, from uber applications to Amazon deliveries. Variation coefficient and relative percentage difference are two types of statistical indicators that are employed in the process of studying and verifying this model. To display and contrast the findings, the execution times in seconds are also considered. |
16,386 | Please write an abstract with title: GPS time synchronization in school-network cosmic ray detectors, and key words: Global Positioning System, Data acquisition, Satellite broadcasting, Detectors, Synchronization, Large-scale systems, Atomic clocks, Educational institutions, Nuclear physics, Nuclear electronics. Abstract: The QuarkNet DAQ card for school-network cosmic ray detectors provides a low-cost alternative to using standard particle and nuclear physics fast pulse electronics modules. The board, which can be produced at a cost of less than US$500, produces trigger time and pulse edge time data for 2 to 4-fold coincidence levels via a universal RS232 serial port interface, usable with any PC. Individual detector stations, each consisting of 4 scintillation counter modules, front-end electronics, and a GPS receiver, produce a stream of data in form of ASCII text strings in identifiable set of formats for different functions. The card includes a low-cost GPS receiver module, which permits timestamping event triggers to about 50 nanosecond accuracy in UTC between widely separated sites. The technique used for obtaining precise GPS time employs the 1PPS signal, which is not normally available to users of the commercial GPS module. We had the stock model slightly custom-modified to access this signal. The method for deriving time values was adapted from the procedure developed for the K2K long-baseline neutrino experiment]. |
16,387 | Please write an abstract with title: Design, Fabrication and Performance Evaluation of Conductors in Tube Cables, and key words: Superconducting cables, Power cables, Bending, High-temperature superconductors, Critical current density (superconductivity), Electron tubes, Superconducting films. Abstract: With excellent mechanical properties and electromagnetic properties, compact superconducting cables are considered as potential candidates for large capacity power applications and fusion magnets. In this paper, the concept of a novel compact cable, conductors in tube (CIT) cable is introduced from the aspect of design, fabrication, and performance evaluation, respectively. The principal advantages of CIT cables are that the cable can release the residual stress created from the fabrication process, and the outer former of the cable can be used as both the supporter as well as the container of refrigerant liquid. Firstly, the topological structure and the detailed fabrication process of a CIT cable are presented. Then, a typical CIT cable is manufactured. The feasibility of this new structure is verified by its critical current test. Moreover, bending characteristics of CIT cables are evaluated and compared with Conductors on Round Core (CORC) cables from the aspect of both simulation and experiments. The superior bending performance enables it to be potential in the future compact magnet application. |
16,388 | Please write an abstract with title: Circuit model for given reflectance data constructed with mixed lumped and distributed elements for high speed/high frequency communication systems, and key words: Circuits, Reflectivity, Frequency, Interpolation, Reflection, Transmission line measurements, Distributed computing, Physics computing, Inductors, Shunt (electrical). Abstract: In this paper, a reflectance-based "nonlinear interpolation method" is presented to model the measured or computed data, obtained from a "passive one-port physical device" using mixed lumped and distributed elements. Mixed element model is constructed with cascade connection of series inductors [L], commensurate transmission lines or so called unit elements [UE| and shunt capacitors [C]. Basis of the new model rests on the numerical generation of the scattering parameters of the lossless two-port constructed with cascade connection of simple [L]-[UE]-[C] elements which describes a lossless 2-port in Darlington sense. The new modeling technique does not require direct optimization of the circuit elements of the selected topology. Rather, two-variable reflection coefficient is directly determined by means of a nonlinear but "convergence guaranteed" interpolation process to best fit the given data. A low-pass filter input reflection coefficient modeling example is included to exhibit the utilization of the proposed modeling method. |
16,389 | Please write an abstract with title: Combined Deep Learning With Directed Acyclic Graph SVM for Local Adjustment of Age Estimation, and key words: Estimation, Faces, Face recognition, Feature extraction, Support vector machines, Deep learning, Active appearance model. Abstract: In order to further improve the accuracy of age estimation, a locally adjusted age estimation algorithm based on deep learning and directed acyclic graph SVM is proposed. In the training phase, SE-ResNet-50 network pre-trained by the VGGFace2 dataset is first fine-tuned. Once the network converges, and the vector consisting of the parameters of the last fully connected layer is used as a representation and train multiple One-Versus-One SVMs. In the test phase, we first sent the face image to be estimated into SE-ResNet-50 to obtain a rough age estimation value, then set the specific neighborhood, and finally combined the trained SVM into a directed acyclic graph SVM and set specific neighborhood with the global estimate as the center for accurate age estimate. In order to show the universality of the proposed coarse-to-fine or/and global-to-local method, experiments were carried out on MORPH and AFAD images of different races, and the results verified the effectiveness of the algorithm. |
16,390 | Please write an abstract with title: Two dimensional timeline and its application to Conversant Media system, and key words: Electronic learning, Prototypes, Streaming media, Databases, Histograms, Feedback, Workstations, Watches, Video sharing, Delay. Abstract: We present a two dimensional timeline to replace the conventional 1D timeline used in video annotation systems. The extra dimension is augmented to represent the text annotations from user input and link them to the corresponding video time. A histogram of user annotations is developed over time. Not only does it highlight the history of prior user interaction with the video annotation system, it also gives a bird's eye view of how annotations are distributed along the video timeline. Users can then quickly find the annotation hotspots. Using this unique 2D timeline, we have developed a video annotation system prototype, Conversant Media (CM). Experimental trials conducted at two educational institutes on presentation skill training yield encouraging feedback, one of which concluded that CM can become a potential alternative to classroom visits for trainee teachers |
16,391 | Please write an abstract with title: Mapping High-Resolution Global Impervious Surface Area: Status and Trends, and key words: Remote sensing, Spatial resolution, Earth, Artificial satellites, Land surface, Classification tree analysis, Surface topography. Abstract: Impervious surface area (ISA) mapping at the global scale has entered a new era. Currently, the number of high-resolution global ISA products is gradually increasing; however, a literature review that systematically investigates these ISA products is still lacking, which limits the application of these products. Thus, we provide a comprehensive analysis of the existing high-resolution global ISA products, concentrating on the aspects of the data sources, training samples, features, and methods. Moreover, we evaluate these products at multitemporal and multispatial scales, using a series of independent test samples. The results demonstrate that the multitemporal accuracy of the ISA products presents an increasing trend, due to the increase of the available sensors. Among the continuous time-series products [e.g., the updated new global impervious surface area (GISA 2.0), the global impervious surface area (GISA), global annual urban dynamics, global human settlement layer, and global artificial impervious areas], the accuracy of the GISA 2.0 outperforms the others at global, continental, and regional scales. However, the mapping performance of these products in small towns and arid and rural regions needs to be enhanced. In particular, we focus on the spatio-temporal disagreement of the ISA products. We show that the high disagreement regions are predominantly concentrated in eastern Asia, western Europe, and eastern North America. In addition, the high disagreement regions are characterized by low ISA density, high vegetation coverage, and high albedo bare ground coverage. Additionally, this article concludes with some remarks about the future directions of global ISA mapping. |
16,392 | Please write an abstract with title: A Thermal Failure Model for MOSFETs Under Repetitive Electromagnetic Pulses, and key words: MOSFET, Heating systems, Semiconductor device modeling, Silicon, Mathematical model, Electromagnetics, Electrodes. Abstract: A thermal failure model for MOSFETs under repetitive electromagnetic pulses is investigated in this paper. The analytic equation to analyze the relationship between the temperature rise and pulse parameters is given by a theoretical derivation. The electro-thermal process of a 180 nm MOSFET is simulated as an example. It shows that the model agrees well with the technology computer aided design (TCAD) results. Some discussions on the influence of the dissipation performance and on the electro-thermal coupled effect are given. Both the theoretical model and the TCAD results indicate that most of the failures occur in 1 or 2 cycles. Further increase in the pulse number does not change the failure probability. Influence of heat dissipation performance of the substrate is discussed. This work is useful for further failure analysis, and is also helpful in protection design for the MOSFET device and circuit under HPMs and other repetitive electromagnetic pulses. |
16,393 | Please write an abstract with title: Region-of-Interest video coding by fuzzy control for H.263+ standard, and key words: Video coding, Fuzzy control, Teleconferencing, Image coding, Humans, Face, Video codecs, Quantization, Fuzzy logic, Communication system control. Abstract: This paper proposes an Region-of-Interest(ROI) video coding algorithm based on H.263+. The ability to give higher priority to ROI is the emerging functionality for video coding nowadays. In most videoconferencing and videophony, most existing compression schemes treat the entire image uniformly. However, the background is much less critical than the foreground, i.e., human face, moving objects, etc., for communication. A region-based video codec based on the H.263+ with the optional mode of modified quantization is set up. A new algorithm based on TMN8 utilizes a fuzzy logic control method to give adaptively weighted factors to each macroblock(MB) and allocate different bits to each MB according to the complexity and the variance variation in the rate-and-distortion model. From experimental results, the proposed method can significantly improve the quality at ROI and multiple ROI functionality also has been implemented. Our method is suitable for real time videoconferencing. |
16,394 | Please write an abstract with title: Evaluation of HMM training algorithms for letter hand gesture recognition, and key words: Hidden Markov models, Application software, Computer vision, Digital cameras, Streaming media, Smoothing methods, Viterbi algorithm, Databases, Handheld computers, Mobile handsets. Abstract: The paper introduces an application using computer vision for letter hand gesture recognition. A digital camera records a video stream of hand gestures. The hand is automatically segmented, the position of the hand centroid is calculated in each frame, and a trajectory of the hand is determined. After smoothing the trajectory, a sequence of angles of motion along the trajectory is calculated and quantized to form a discrete observation sequence. Hidden Markov models (HMMs) are used to recognize the letters. Baum Welch and Viterbi path counting algorithms are applied for training the HMMs. Our system recognizes all 26 letters from A to Z and the database contains 30 example videos of each letter gesture. We achieve an average recognition rate of about 90 percent. A motivation for the development of this system is to provide an alternate text input mechanism for camera enabled handheld devices, such as video mobile phones and PDAs. |
16,395 | Please write an abstract with title: Steganographic Information Hiding Method based on Continuous Wavelet Transform, and key words: Steganography, Embedded computing, Continuous wavelet transforms, Image processing, Arrays, Matlab. Abstract: This article considers continuous wavelet transforms as a method of steganographic embedding of confidential information in an image. The relevance of steganography is shown by the example of hiding information in a jpg file. The paper shows data hiding algorithm, the theoretical justification of the presented method, Matlab implementation of the presented algorithm and analysis of the results of the study. |
16,396 | Please write an abstract with title: Building distributed embedded systems with RTLinux-GPL, and key words: Embedded system, Linux, TCPIP, Real time systems, File systems, Hardware, Kernel, Time factors, Yarn, Guidelines. Abstract: Linux has revealed in the last few years as an appealing option for developing embedded systems but there are some extra requirements of embedded systems that Linux does not fulfill, such as real-time capabilities, file system size and specific hardware support. Real-time features can be achieved with Real-Time Linux GPL (hereafter RTLinux), which is a small, deterministic, real-time kernel that handles time-critical tasks and runs Linux as its lowest priority execution thread. However RTLinux has also important drawbacks. One of them is that real-time tasks cannot make use of Linux services and, in particular, TCP/IP networking. This paper describes RTL-lwIP, which is a TCP/IP stack for embedded systems based on the lwIP (lightweight) TCP/IP stack that runs on RTLinux and can be used by real-time tasks. RTL-lwIP allows real-time tasks to communicate directly with remote real-time tasks or even with Linux user processes. The importance of introducing TCP/IP on RTLinux is that it enables the possibility of developing real-time distributed embedded systems based on CORBA, thus allowing interoperability with other platforms and Web-integration. This paper describes the porting of the lwIP TCP/IP stack to RTLinux and gives some guidelines in order to implement RTLinux drivers for Ethernet cards using as example the implementation of a RTLinux driver for the 3Com905C-X NIC (Network Interface Card). |
16,397 | Please write an abstract with title: Noise of Negative Resistance Oscillators at High Modulation Frequencies, and key words: Oscillators, Frequency modulation, Superconducting device noise, Impedance, Circuit noise, Polynomials, Diodes, Fluctuations, Bandwidth, Equivalent circuits. Abstract: The theory of AM and FM noise in oscillators of the negative resistance type is extended to higher modulation frequencies, i.e., to modulation frequencies beyond the bandwidth of the stabilizing cavity. The results are expressed in terms of the input impedance of the stabilizing cavity and are found to agree well with measurements. |
16,398 | Please write an abstract with title: Audio watermarking under desynchronization and additive noise attacks, and key words: Watermarking, Additive noise, Robustness, Distortion, Game theory, Context, Signal processing, Degradation, Payloads, Interference. Abstract: Digital watermarking is often modeled as the transmission of a message over a noisy channel denoted as "watermark channel". Distortions introduced by the watermark channel result mainly from attacks and may include interference from the original signal. One of the main differences with classical transmission situations stems from the fact that perceived distortions have to be taken into account. However, measuring the perceived impact an attack has on a watermarked signal is currently an unsolved problem. Possible means of circumventing this problem would be 1) to define the distortion in a so-called "perceived domain" and define an "ad hoc" equivalence between objective and perceived distortion or 2) to define an "equivalent distortion" by removing from the attack noise the part that is correlated to the host signal. This paper concentrates on the second approach and first shows that the resulting "equivalent" attack is a particular case of a thoroughly studied channel: filtering plus additive noise. However, the approach in this paper emphasizes the fact that the additive noise in the model has to be decorrelated with the signal. Then, the formalism is applied to (desynchronization plus noise) attacks on audio signals. In this context, this paper provides the corresponding capacities, as well as optimal "attack" and "defense" strategies in a game theory context. |
16,399 | Please write an abstract with title: Video coding with flexible MCTF structures for low end-to-end delay, and key words: Video coding, Filters, Delay effects, Encoding, Telecommunications, Codecs, Spatial resolution, Signal resolution, Filtering, Research and development. Abstract: Some of the most powerful schemes for scalable video coding are based on the so-called (t + 2D) paradigm and provide coding performance competitive with state-of-the-art codecs. However, the temporal multiresolution schemes used in such codecs introduce a non-negligible delay, preventing their use in applications which require low latency, like video conferencing or video streaming. In this paper, we provide a flexible approach to reduce the end-to-end delay involved in motion-compensated temporal filtering schemes. We show by simulations results the trade-offs observed between coding efficiency and low end-to-end delay. |
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