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18,600 | Please write an abstract with title: Obstacle detection for start-inhibit and low speed driving, and key words: Vehicle detection, Road safety, Predictive models, Machine vision, Layout, Accidents, Object detection, Cameras, Image segmentation, Pixel. Abstract: The work described in this paper has been developed in the framework of the integrated project APALACI-PReVENT, a research activity funded by the European Commission to contribute to road safety by developing and demonstrating preventive safety technologies and applications. The goal of the system presented in this work is the development of a vision system for detecting potential obstacles in front of a slowly moving or still vehicle. When the vehicle is still, a background subtraction approach is used assuming that the background keeps stationary for a limited amount of time; thus, a reference background is computed and used to detect changes into the scene. A different approach is used when the vehicle is moving. The system, by means of inertial sensors, can detect ego-motion and correct background information accordingly. A temporal stereo match technique, able to detect obstacles in moving situations, completes the system. According to experimental results, the proposed algorithm can be useful in different automotive applications, requiring real-time segmentation without assumptions on background motion. |
18,601 | Please write an abstract with title: Ultrasonic Piezoelectric Mems Speakers for In-Ear Applications: Bubbles-Like and Pistons-Like Innovative Designs, and key words: Micromechanical devices, Fabrication, Performance evaluation, Total harmonic distortion, Nonlinear distortion, Resonant frequency, Acoustics. Abstract: MEMS speakers are attracting increasing interest thanks to their reduced size, low cost and power efficiency. Research work is still needed in terms of Sound Pressure Level (SPL) improvement at low frequency and of Total Harmonic Distortion (THD) reduction to obtain devices competitive with the non-MEMS counterparts.In this work, two innovative PZT-driven MEMS speakers for in-ear applications are designed and simulated. They consist of arrays of mechanical structures excited through PZT patches properly designed that do not need any protecting membrane. Thanks to the resonance frequency in the ultrasonic regime, they represent a very promising solution for the design of high fidelity and high-performance speakers. The ultrasonic resonance of the mechanical structure indeed guarantees a flat and high SPL at low frequencies and a moderate intrinsic THD. |
18,602 | Please write an abstract with title: System Characteristics, and key words: Transient analysis, Impedance, Zinc, Synchronous generators, Switches, Steady-state, Power systems. Abstract: Fault currents in a power system depend on the impedance of the system between the generating sources and the fault location, on the prefault current flowing in a given line contributing to the total fault, and on the point on the sine wave of voltage at which the fault occurs. This chapter begins with the characteristics of short‐circuit currents themselves, and the way in which the currents are affected by the synchronous generators and ac motors on the system. It presents commonly used switching station arrangements. The chapter reviews the characteristics of the passive transmission and distribution circuits and the impedance calculations that are necessary in order to solve for fault currents. The compensation theorem from network theory provides a useful method for examining the change in the currents and voltages of a linear network when a change in impedance occurs. |
18,603 | Please write an abstract with title: Modeling of passively Q-switched Er/sup 3+//Yb/sup 3+/-codoped clad-pumped fiber lasers, and key words: Erbium, Fiber lasers, Equations, Laser modes, Optical propagation, Spontaneous emission, Power lasers, Pump lasers, Optical pulses, Space vector pulse width modulation. Abstract: We present the modeling of passively Q-switched Er/sup 3+//Yb/sup 3+/-codoped double-clad fiber lasers (EYDFL). Both two-level and three-level saturable absorbers (SAs) are used. The model is based on detailed rate equations of SAs, Er/sup 3+/, and Yb/sup 3+/ populations in the fiber, and light propagation equations including spontaneous emissions due to both Er/sup 3+/ and Yb/sup 3+/. Laser output characteristics including pulse energy, width, peak power, repetition frequency (PRF), and average power are computed as functions pump power, fiber length, single-mode/multi-mode fibers, Er/sup 3+//Yb/sup 3+/ concentrations, out-coupling reflectivity, focus area on the SA, and SA doping and length. Several transition metal-doped crystal SAs and semiconductor SA mirrors (SESAM) are considered and compared. |
18,604 | Please write an abstract with title: Position sensing for high track density recording, and key words: Magnetic heads, Equations, Disk recording, Linearity, Hardware, Disk drives, Noise level, Digital recording, Stability, Frequency. Abstract: Progress towardhigher digital areal densities is related to the data track position sensing accuracy obtainable in future disk drives. In most systems available, position sensing is done remotely from the data track and subject to different dimensional stability conditions. To obtain higher track densities, position sensing reference information must be moved near the data track. Several techniques are available to embed reference information in the data track. All the techniques described have one of two basic principles of operation. One method uses comparison of reference signal amplitudes and the second method uses arrival time differences of reference signals. The time method is relatively unknown but offers the designer some new alternatives. This paper describes an overview of several methods. Relationships are derived to relate the influence of noise on both basic methods. Linearity, relative hardware simplicity, and track capture range are also discussed. It is our conclusion that the Amplitude or Tri-Bit method offers the greatest hardware simplicity, but is limited by noise and non-linearity at high track densities. The time dependent or Chevron method requires two data channels, but offers a relatively higher noise immunity, better linearity, and higher data capacity. |
18,605 | Please write an abstract with title: Evaluating Bandwidth Efficiency and Latency of Scheduling Schemes for 5G Fronthaul over TDM-PON, and key words: Spectral efficiency, 5G mobile communication, Europe, Optical fiber communication, Complexity theory. Abstract: We propose scheduling schemes for Cooperative DBA in upstream TDM-PON to enable 5G fronthaul services and evaluate their bandwidth efficiency and latency performance against FBA and conventional DBA using a co-simulation of a 25GS-PON MAC and a 5G system level simulator. |
18,606 | Please write an abstract with title: Sustainable Learning Micro-Credential using Blockchain for Student Achievement Records, and key words: Productivity, Technological innovation, Costs, Bibliographies, Education, Documentation, Solids. Abstract: This research objective is to present assessment and management to ensure the confidentiality of documents that are permanent, transparent, and sustainable for students by utilizing Blockchain technology and can be accessed directly by students. Maintained confidentiality of documents allows students to personalize the value of education and produce permanent documentation in formal and informal learning and determine the lifelong learning path of each individual. The method in this research using the Literature Review Study to learn problems from research with the theme of blockchain-based student achievement credentials in the world of education. The implication of this research is to provide an analysis of the use of blockchain micro-credentials on student achievement records in universities using the Literature Review Study Method. The results show that blockchain guarantees a foundation for student achievement record credentials that are durable, secure, and offer solid administration in managing student credentials. They can control them on an ongoing basis. Universities are also given the advantage of increasing student file security and reducing administrative and bureaucratic costs. Further research can be carried out by combining blockchain with AI innovation and private key and decentralized cloud to address issues concerning productivity, flexibility, capacity, and tighter security. With future updates, it is hoped that the use of blockchain in student achievement credentials can become more mature and can be applied to 1000 universities in Indonesia. |
18,607 | Please write an abstract with title: Attention-Based Curiosity-Driven Exploration in Deep Reinforcement Learning, and key words: Deep learning, Conferences, Reinforcement learning, Signal processing, Probabilistic logic, Acoustics, Speech processing. Abstract: Reinforcement Learning enables to train an agent via interaction with the environment. However, in the majority of real-world scenarios, the extrinsic feedback is sparse or not sufficient, thus intrinsic reward formulations are needed to successfully train the agent. This work investigates and extends the paradigm of curiosity-driven exploration. Our aim is to develop means for the better incorporation of state-and/or action-dependent information into existing intrinsic reward formulations. First, a probabilistic approach is taken to exploit the advantages of the attention mechanism, which is successfully applied in other domains of Deep Learning. Combining them, we propose new methods, such as Attention-aided Advantage Actor-Critic, an extension of the Actor-Critic framework. Second, another curiosity-based approach - Intrinsic Curiosity Module - is extended. The proposed model utilizes attention to emphasize features for the dynamic models within Intrinsic Curiosity Module, moreover, we also modify the loss function, resulting in a new curiosity formulation, which we call rational curiosity (RCM). The corresponding implementation can be found at https://github.com/rpatrik96/AttA2C/. |
18,608 | Please write an abstract with title: Approximate processing of massive continuous quantile queries over high-speed data streams, and key words: Data mining, Query processing, Stock markets, Computer science, Computer Society, Computer applications, Application software, Data analysis, Costs, Clustering algorithms. Abstract: Quantile computation has many applications including data mining and financial data analysis. It has been shown that an /spl epsi/-approximate summary can be maintained so that, given a quantile query (/spl phi/,/spl epsi/), the data item at rank /spl lceil//spl phi/N/spl rceil/ may be approximately obtained within the rank error precision /spl epsi/N over all N data items in a data stream or in a sliding window. However, scalable online processing of massive continuous quantile queries with different /spl phi/ and /spl epsi/ poses a new challenge because the summary is continuously updated with new arrivals of data items. In this paper, first we aim to dramatically reduce the number of distinct query results by grouping a set of different queries into a cluster so that they can be processed virtually as a single query while the precision requirements from users can be retained. Second, we aim to minimize the total query processing costs. Efficient algorithms are developed to minimize the total number of times for reprocessing clusters and to produce the minimum number of clusters, respectively. The techniques are extended to maintain near-optimal clustering when queries are registered and removed in an arbitrary fashion against whole data streams or sliding windows. In addition to theoretical analysis, our performance study indicates that the proposed techniques are indeed scalable with respect to the number of input queries as well as the number of items and the item arrival rate in a data stream. |
18,609 | Please write an abstract with title: Preserving distributed systems critical properties: a model-driven approach, and key words: Quality of service, Software quality, Throughput, Availability, Scalability, Data security, Software maintenance, Software systems, Distributed computing, Testing. Abstract: The need for creating predictability in distributed systems is most often specified in terms of quality-of-service (QoS) requirements, which help define the acceptable levels of dependability with which capabilities such as processing capacity, data throughput, or service availability reach users. For longer-term properties such as scalability, maintainability, adaptability, and system security, we can similarly use persistent software attributes (PSAs) to specify how and to what degree such properties must remain intact as a network expands and evolves over time. The Skoll distributed continuous software quality assurance process helps to identify viable system and software configurations for meeting stringent QOS and PSA requirements by coordinating the use of distributed computing resources. The authors tested their process using the large, rapidly evolving ACE+TAO middleware suite. |
18,610 | Please write an abstract with title: Edge-Aware Superpixel Segmentation with Unsupervised Convolutional Neural Networks, and key words: Image segmentation, Image edge detection, Conferences, Predictive models, Prediction algorithms, Convolutional neural networks, Task analysis. Abstract: Superpixels provide an efficient representation of images, and are applicable for subsequent vision tasks. In this paper, we propose an edge-aware superpixel algorithm based on an unsupervised convolutional neural network (CNN). Noticing that to adhere the boundaries of objects is one of the most essential characteristics of superpixels, we propose an entropy-based edge-aware term, which helps fit the differential model of the pixel-superpixel soft-assignment matrix predicted from CNN to image gradients, i.e. generate boundary-aligning superpixels. The proposed algorithm yields more boundary-adhering superpixels, and experimental results on BSDS500 show the effectiveness of the proposed edge-aware term. |
18,611 | Please write an abstract with title: Two-level rolling strategy for single-machine scheduling problem with release times, and key words: Single machine scheduling, Processor scheduling, Information science, Control engineering, Mathematics, Computational efficiency, Costs. Abstract: A kind of rolling horizon procedures for single-machine scheduling problem is presented to deal with the incomplete global information at decision time. At each decision time the known information should be sufficiently considered while the size of the rolling window on the sub-problem is should be limited in order to limit computational cost. The two-level rolling horizon scheduling strategy is presented to deal with the conflict. The first-level is preliminary scheduling based on the predictive windows and the second-level is locally scheduling with terminal penalty based on the rolling windows. The estimated global performance is getting close to the ultimately realized actual cost and its getting better and better while the new information is obtained and the decision time is being put forward. |
18,612 | Please write an abstract with title: Exact reconstruction techniques for tree-structured subband coders, and key words: Finite impulse response filter, Phase distortion, Frequency, Decoding, Speech analysis, Performance analysis, Band pass filters, Speech coding, Channel coding, Signal analysis. Abstract: In recent years, tree-structured analysis/reconstruction systems have been extensively studied for use in subband coders for speech. In such systems, it is imperative that the individual channel signals be decimated in such a way that the number of samples coded and transmitted do not exceed the number of samples in the original speech signal. Under this constraint, the systems presented in the past have sought to remove the aliasing distortion while minimizing the overall analysis/reconstruction distortion. In this paper, it is shown that it is possible to design tree-structured analysis/reconstruction systems which meet the sampling rate condition and which result in exact reconstruction of the input signal. The conditions for exact reconstruction are developed and presented. Furthermore, it is shown that these conditions are not overly restrictive and high-quality frequency division may be performed in the analysis section. A filter design procedure is presented which allows high-quality filters to be easily designed. |
18,613 | Please write an abstract with title: Official statistics, and key words: Internet, Data collection, Statistics, Sociology, Soft sensors, Market research, Data integration. Abstract: The term <i>quality of statistical data</i>, developed and used in official statistics and international organizations such as the IMF and the OECD, refers to the usefulness of summary statistics and indicators generated by producers of official statistics. Similarly, in the context of survey quality, official agencies such as Eurostat, NCSES, and Statistics Canada (Statistics Canada, 2002, Statistics Canada's Quality Assurance Framework. Statistics Canada, Ottawa) created dimensions for evaluating the ability of a survey to provide “accurate survey data.” In this chapter, we compare and contrast the InfoQ framework and dimensions with those used by statistical agencies. We discuss how the InfoQ approach can support official statistics used not only by governments for policy decision making but also by other stakeholders such as industry and service organizations by integrating official and organizational data. |
18,614 | Please write an abstract with title: Density Based Clustering Methods for Road Traffic Estimation, and key words: Object detection, Roads, Interpolation, Image resolution, Estimation, Cameras, Computational modeling. Abstract: Multiple object detection using deep neural networks can lead to transportation vehicles estimate, a necessary requirement for prediction and management of road traffic and parking lot. Highly overlapped objects that look similar and objects that are there at far distances have lesser probability of detection by state-of-art techniques. We propose techniques to estimate the traffic at regions of poor detection probability in the image based on (i) density based clustering and (ii) exclusive object detection in the regions of poor detection. The proposed techniques lead to better estimation in comparison to state-of-art by approximately 12 %. We have utilized RetinaNet and YOLOv3 networks for object detection. |
18,615 | Please write an abstract with title: Optimal design for power system dynamic stabilizer by grey prediction PID control, and key words: Power system dynamics, Three-term control, Optimal control, Control systems, Power system reliability, Power system modeling, Predictive models, Power generation, Signal generators, Design methodology. Abstract: In this paper, we proposed an effective method to design the power system stabilizers (PSS). The design of a PSS can be formulated as an optimal linear regulator control problem; however, implementing this technique requires the design of estimators. This increases the implementation and reduces the reliability of control system. Therefore, favor a control scheme that uses only some desired state variables, such as torque angle and speed. To deal with this problem, we use the optimal reduced models to reduce the power system model into two state variables system by each generator and use grey prediction PID control to find control signal of each generator. Moreover, we will apply genetic algorithms (GAs) to find the appropriate parameter values for the desired system. Finally, the advantages of the proposed method are illustrated by numerical simulation of the two machines-infinite-bus power systems. |
18,616 | Please write an abstract with title: Requirement-based design methods for adaptive communications links, and key words: Design methodology, Bit error rate, Logic design, Frequency, Voltage, CMOS logic circuits, Space technology, Clocks, Jitter, Laboratories. Abstract: High-speed communications link cores must consume low-power, feature, low bit-error-rates (BER), and address many applications. We pFsent a methodology to design adaptive link architectures, whereby the link's intemal logic complexity, frequency, and supply are simultaneously adapted to application requirements. The requirement space is mapped to the design space using requirements measurement circuits and configurable logic blocks. CMOS results indicatk that power savings of 60% versus the worst case arc Dossible. while the area overhead is keot under 5%. |
18,617 | Please write an abstract with title: Forecasting Forward Patent Citations: Comparison of Citation-Lag Distribution, Tobit Regression, and Deep Learning Approaches, and key words: Patents, Technological innovation, Forecasting, Machine learning, Telecommunications, Art, Industries. Abstract: This article aims to compare the existing approaches, such as citation-lag distribution, Tobit regression, and multilayered neural network to forecast forward patent citations as a proxy for patent technological impact. For the purpose of analysis, in this article, we focuse on estimating lifespan forward citations in the telecommunications sector because sector-specific characteristics may affect the citation patterns. Accordingly, U.S. utility patents in the telecommunications sector are collected and the patent ex-ante information (the information provided at the point of patent disclosure) along with patent ex-post information (the information available after patent disclosure) are extracted to be used for forecasting forward citations. The research findings indicate that the deep learning approach tends to outperform the other approaches only with the ex-ante information, and the performance of the deep learning approach increases significantly when the ex-post information is added to the ex-ante information. This article is expected to offer useful guidelines for choosing an appropriate approach to forecast citations based on available dataset. |
18,618 | Please write an abstract with title: A Simplified Model-Free Self-Evolving TS Fuzzy Controller for Nonlinear Systems with Uncertainties, and key words: Self-evolving fuzzy controller, model-free controller, uncertainties, adaptive control.. Abstract: This paper proposes a self-evolving Takagi-Sugeno fuzzy controller for nonlinear systems with uncertainties. The self-evolving framework is used to add and prune fuzzy rules in an online manner. Our proposed nonlinear controller is model-free and does not depend on the plant dynamics. All adjustable fuzzy parameters are tuned using a sliding surface, which is derived from the gradient descent learning method to minimize the error between the desired and the actual signals. Unlike most of the existing self-evolving controllers, where a hybrid technique is required to determine the control action, our proposed algorithm is able to construct the final control signal, which can be fed directly to control a nonlinear system. The tracking performance of our proposed controller is validated and compared with an adaptive model-based fuzzy controller in the presence of external disturbances, where better tracking results are obtained from our proposed controller. |
18,619 | Please write an abstract with title: Design and Control of an Aquatic Robot with RGB-D Sensor, and key words: Image segmentation, Aquatic robots, Navigation, Robot vision systems, Neural networks, Control systems, Organisms. Abstract: Bio-inspired robotics is a relatively new field of engineering, which aims at mimicking living organisms for various applications. It focuses on building autonomous machines that can be operated in remote, inaccessible or dangerous environments, where the presence of humans or other systems is not possible. The main goal of this work is to develop a reactive control system architecture for an aquatic robot based on the feedback acquired from a Red Green Blue-Depth (RGB-D) camera to navigate and plan the path efficiently. The proposed solution is based on image segmentation and distance estimation using the depth data. This data is then imputed to a small neural network that implements a low-level reflex controller that governs the robot’s body curvature in order to alter it’s trajectory. The so controlled robot exhibits different behaviors like avoid obstacles in an aquatic environment and detect energy sources. The design of the aquatic robot is introduced based on segments connected with two degrees of freedom joints moved by a tendons actuation system. |
18,620 | Please write an abstract with title: High-Speed Collision Avoidance using Deep Reinforcement Learning and Domain Randomization for Autonomous Vehicles, and key words: Training, Autonomous vehicles, Reinforcement learning, Neural networks, Task analysis, Collision avoidance, Feature extraction. Abstract: Recently, deep neural networks trained with Imitation-Learning techniques have managed to successfully control autonomous cars in a variety of urban and highway environments. One of the main limitations of policies trained with imitation learning that has become apparent, however, is that they show poor performance when having to deal with extreme situations at test time- like high-speed collision avoidance - since there is not enough data available from such rare cases during training. In our work, we take the stance that training complex active safety systems for vehicles should be performed in simulation and the transfer of the learned driving policy to the real vehicle should be performed utilizing simulation to-reality transfer techniques. To communicate this idea, we setup a high-speed collision avoidance scenario in simulation and train the safety system with Reinforcement Learning. We utilize Domain Randomization to enable simulation-to-reality transfer. Here, the policy is not trained on a single version of the setup but on several variations of the problem, each with different parameters. Our experiments show that the resulting policy is able to generalize much better to different values for the vehicle speed and distance from the obstacle compared to policies trained in the non-randomized version of the setup. |
18,621 | Please write an abstract with title: Depression Detection Using Asynchronous Federated Optimization, and key words: Privacy, Social networking (online), Blogs, Sociology, Depression, Collaborative work, Prediction algorithms. Abstract: With the rapid growth of population, the life pressure, and the various intensive pressures every day deepen the competition among people more intensive. Tens of millions of people have been suffering from depression every year and only a fraction receives adequate treatment. The development of social networks such as Facebook, Twitter, Weibo, and QQ provides more convenient communication and provides a new emotional release window. People communicate with their friends and share their opinions to express their feelings. It provides an opportunity to detect depression in social networks. Although using social networks to detect depression has picked an established position on a global scale, few researchers consider the data security and privacy-preserving schemes. Therefore, we propose the federated learning technique as an efficient and scalable method. With the larger number of social networks data from diverse edge devices, federated learning can process a large number of edge devices in parallel. For the study, we aim to analyze depression on Weibo collected from an online social network. We propose a novel algorithm Text-CNN Asynchronous Federated optimization (CAFed) based on federated learning to improve the communication cost and convergence rate. We have shown our proposed method can effectively protect users' privacy under the premise of ensuring the accuracy of prediction. We prove that our proposed method's convergence rate is faster than the Federated Averaging (FedAvg) for non-convex problems. Federated learning techniques identify high-quality solutions to mental health issues among Weibo users. |
18,622 | Please write an abstract with title: Reinforcement Learning Based Outdoor Navigation System for Mobile Robots, and key words: Training, Location awareness, Q-learning, Navigation, Simulation, Path planning, Mobile robots. Abstract: This paper presents a navigation system for mobile robots in outdoor environments and the preliminary robot implementation results. Objectives of the proposed navigation system include path generation on the map (2D binary image) and path following of the robot to reach the goal location. In our method there is no waypoint in the generated paths and the map. The A-Star search algorithm is employed to plan paths on the map, and the q-learning is used to train the robot to follow the generated paths. The difference between the robot positions and A-star generated random paths is used to evaluate the performance of the proposed method. Preliminary simulation results revealed the potentials of the cooperation between reinforcement learning-based algorithms and conventional path planning algorithms for robot navigation. |
18,623 | Please write an abstract with title: Efficient Feature Compression for the Object Tracking Task, and key words: Video coding, Image coding, Tensors, Codes, Neural networks, Video compression, Servers. Abstract: In object tracking systems, often clients capture video, encode it and transmit it to a server that performs the actual machine task. In this paper we propose an alternative architecture, where we instead transmit features to the server. Specifically, we partition the Joint Detection and Embedding (JDE) person tracking network into client and server side sub-networks and code the intermediate tensors i.e. features. The features are compressed for transmission using a Deep Neural Network (DNN) we design and train specifically for carrying out the tracking task. The DNN uses trainable non-uniform quantizers, conditional probability estimators, hierarchical coding; concepts that have been used in the past for neural networks based image and video compression. Additionally, the DNN includes a novel parameterized dual-path layer that comprises of an autoencoder in one path and a convolution layer in the other. The tensor output by each path is added before being consumed by subsequent layers. The parameter value for this dual-path layer controls the output channel count and correspondingly the bitrate of transmitted bitstream. We demonstrate that our model improves coding efficiency by 43.67% over state-of-the-art Versatile Video Coding standard that codes the source video in pixel domain. |
18,624 | Please write an abstract with title: Design and Implementation of a Network Coding Platform based on NetFPGA and ns-3, and key words: Wireless networks, Software algorithms, Switches, Interference, Network coding, Throughput, User experience. Abstract: In existing wireless networks, path loss and signal interference have a negative impact on the user experience. Network coding is a technique that brings higher throughput and more stable transmission.by network coding based algorithms for end-to-end network performance is seldom addressed which might limit the opportunities applying network coding in reality. In this paper, we propose a network coding platform that consist of Network Simulator 3 (ns-3) and a programmable switch (NetFPGA). The former is used to emulate a wireless network environment for an application while the latter is used to enhance the performance running the network coding based algorithms which are computationally intensive in realtime. We will demonstrate the usage of the proposed platform to evaluate the performance in terms of end-to-end throughput and latency in a WiFi network. Based on such platform, various computationally intensive algorithms can be further designed and investigated in different networks in the future. |
18,625 | Please write an abstract with title: Computational Modeling for Surgical Reconstruction of Aortic Valve by Using Autologous Pericardium, and key words: Valves, Surgery, Image reconstruction, Pediatrics, Diseases, Heart, Hemodynamics. Abstract: The objective of this study was to evaluate the clinical effectiveness of surgical reconstruction of aortic valve using autologous pericardium, and the hemodynamic impact of matching the circumferential direction of the trimmed leaflet to inherent fiber orientation of the pericardium during surgery. A patient specific aortic valve model was built based on CTA data. The reconstructive surgery was carried out on the model following normal operating procedures. FSI simulation was performed to analyze the hemodynamic characteristics among the diseased model, normal model and three operative models with different misaligned angles between the circumferential direction of the substitute and inherent fiber orientation. The differences of EOA, velocity distribution, stress and strain on leaflets, and the valve deformation between the five models were compared and analyzed. The results showed that reconstructive surgery helps enlarge EOA, reduce abnormity of leaflet motion and blood ejection compared to diseased model. There was no significant difference between operative models with different misaligned angles in terms of leaflet motion and flow pattern, but as the misaligned angle increased, greater strain and deformation were observed on leaflets during the diastolic period. The present study demonstrated the instant clinical effectiveness of the reconstructive surgery of aortic valve by the improvement of EOA and flow pattern, and suggested that during the operation it may be unnecessary to match the circumferential direction of the substitute to inherent fiber orientation of the pericardium since the hemodynamic characteristics were insensitive to the fiber alignment, but the strain and deformation increment on the substitutes during diastolic period still raised concern about their durability. |
18,626 | Please write an abstract with title: Improving the depth resolution of STEM-ADF sectioning by 3D deconvolution, and key words: depth resolution, optical sectioning, STEM-ADF, 3D deconvolution, maximum entropy method (MEM), Richardson–Lucy algorithm. Abstract: Although the possibility of locating single atom in three dimensions using the scanning transmission electron microscope (STEM) has been discussed with the advent of aberration correction technology, it is still a big challenge. In this report we have developed deconvolution routines based on maximum entropy method (MEM) and Richardson–Lucy algorithm (RLA), which are applicable to the STEM-annular dark-field (ADF) though-focus images to improve the depth resolution. The new three-dimensional (3D) deconvolution routines require a limited defocus-range of STEM-ADF images that covers a whole sample and some vacuum regions. Since the STEM-ADF probe is infinitely elongated along the optical axis, a 3D convolution is performed with a two-dimensional (2D) convolution over xy-plane using the 2D fast Fourier transform in reciprocal space, and a one-dimensional convolution along the z-direction in real space. Using our new deconvolution routines, we have processed simulated focal series of STEM-ADF images for single Ce dopants embedded in wurtzite-type AlN. Applying the MEM, the Ce peaks are clearly localized along the depth, and the peak width is reduced down to almost one half. We also applied the new deconvolution routines to experimental focal series of STEM-ADF images of a monolayer graphene. The RLA gives smooth and high-P/B ratio scattering distribution, and the graphene layer can be easily detected. Using our deconvolution algorithms, we can determine the depth locations of the heavy dopants and the graphene layer within the precision of 0.1 and 0.2 nm, respectively. Thus, the deconvolution must be extremely useful for the optical sectioning with 3D STEM-ADF images. |
18,627 | Please write an abstract with title: Performance Comparison of AODV and DSDV In Vehicular Ad Hoc Networks, and key words: Vehicular ad hoc networks, Ubiquitous computing, Routing protocols, Reliability, AODV, Mobile computing. Abstract: Vehicle Ad-Hoc Networks (VANETs) are a special type of Mobile Ad-Hoc Network (MANETs). In VANETs, a group of vehicles communicates with each other to transfer data without a need for a fixed infrastructure. In this paper, we compare the performance of two routing protocols: Ad-hoc on Demand Distance Vector protocol (AODV) and Destination-Sequenced Distance Vector protocol (DSDV) in VANETs. We measure the reliability of each protocol in the packet delivery. |
18,628 | Please write an abstract with title: ROM integrated vibration control of stochastically parametered flexible structures, and key words: Heuristic algorithms, Computational modeling, Vibration control, Random variables, Numerical models, Mathematical model, Structural beams. Abstract: This study focusses on the vibration control of linear large scale engineering structures, modelled as continuous system, with varying system parameters. Because of manufacturing limitations or/and measurement errors, system parameters need to be modelled as random variables. Here, system parameters are modelled as non-Gaussian random variables. Mathematically, continuous system is governed by partial differential equations and solved using approximation methods. High fidelity finite element model is the starting point of the analysis. Since numerical approximation involves large number of degrees-of-freedom, solving the system in real time is computationally expensive and application of control algorithm is cumbersome. In this study, a reduced order model is developed to reduce the state space dimension of the problem and further integrated with the control algorithm. Next, controller gain is obtained using linear quadratic regulator in reduced subspace which is used as a feedback to the actuators to produce the required control force for vibration control. A numerical example of flexible cantilever beam is solved to demonstrate the efficacy of the algorithm and probabilistic characterisation is carried out using Monte Carlo simulation. |
18,629 | Please write an abstract with title: Hysteresis of granular FePt:Ag films with perpendicular anisotropy, and key words: Anisotropic magnetoresistance, Magnetic hysteresis, Magnetic films, Coercive force, Analytical models, Magnetic multilayers, Rapid thermal annealing, Nanoparticles, Silver, Magnetization. Abstract: Intergranular interactions in nanostructured FePt:Ag thin films and their effect on magnetic hysteresis are investigated. The films, produced by multilayer deposition plus rapid thermal annealing, consist of FePt nanoparticles embedded in a silver matrix. They are investigated by magnetization measurements and magnetic force microscopy. Analytical model calculations, supported by micromagnetic simulations, are used to elucidate the relation between coercivity, hysteresis-loop slope, and spatial correlations during magnetization reversal. The analytical calculations yield simple expressions for the loop slope and the coercivity as a function of the intergranular exchange. Small intergranular exchange enhances the coercivity, but for strong exchange there is a self-energy cutoff, associated with the onset of cooperative reversal and preventing alpha from becoming negative. |
18,630 | Please write an abstract with title: A Game-Theoretic and Experimental Analysis of Energy-Depleting Underwater Jamming Attacks, and key words: Jamming, Games, Transmitters, Internet of Things, Game theory, Receivers, Batteries. Abstract: Security aspects in underwater wireless networks have not been widely investigated so far, despite the critical importance of the scenarios in which these networks can be employed. For example, an attack to a military underwater network for enemy targeting or identification can lead to serious consequences. Similarly, environmental monitoring applications, such as tsunami prevention, are also critical from a public safety point of view. In this article, we assess a scenario in which a malicious node tries to perform a jamming attack, degrading the communication quality of battery-powered underwater nodes. The legitimate transmitter may use packet-level coding to increase the chances of correctly delivering packets. Because of the energy limitation of the nodes, the jammer's objective is twofold: 1) disrupting the communication and 2) reducing the lifetime of the victim by making it send more redundancy. We model the jammer and the transmitter as players in a multistage game, deriving the optimal strategies. We evaluate the performance both in a model-based scenario and using real experimental data, and perform a sensitivity analysis to evaluate the performance of the strategies if the real channel model is different from the one they use. |
18,631 | Please write an abstract with title: Supervised Machine Learning Modelling of Demand for Outpatient Health-Care Services in Kenya using Artificial Neural Networks and Regression Decision Trees, and key words: Analytical models, Biological system modeling, Medical services, Machine learning, Artificial neural networks, Predictive models, Data models. Abstract: Machine learning models are frequently gaining wide applications in different fields with an emphasis on supervised machine learning for data exploration as in healthcare provision. With an increase in demand for outpatient health care services in Kenya, the Government is faced with the problem of forecasting this type of demand. Its in this regard that this research develops a supervised machine learning model for the modeling and prediction of demand for outpatient health-care services in Kenya using artificial neural networks, Linear Regression analysis and Decision trees. The objectives of this research were to analyze, develop and evaluate machine learning models in the modeling of outpatient healthcare data. Model evaluation was via the deviance residuals and mean squared error. Data used in this research was secondary data obtained from the Kenya Household Health Expenditure Utilization Survey, 2017 in which the R statistical software was used to aid the analysis. A total of nine thousand one hundred and fifty-nine outpatients were used in the research and data attributes were age, gender, cost of outpatient health care sought and number of visits made by the outpatients. Experiment results showed that age and gender of an outpatient were significant factors in the estimation and forecasting of demand for outpatient healthcare services for which the neural network architecture was used in the data training. Cost and Visits were used as primary variables in decision tree construction for the classification and regression decision trees respectively. |
18,632 | Please write an abstract with title: Bayesian Optimization for Efficient Design of Uncertain Coupled Multidisciplinary Systems, and key words: Uncertainty, Couplings, Optimization, Bayes methods, Reliability, Gaussian processes, Approximation algorithms. Abstract: Stabilization of complex cyber-physical systems is extremely important in keeping the critical infrastructure and the environment safe. This is, in particular, critical in coupled multidisciplinary systems with several subsystems interacting with each other in an uncertain environment. The design of stabilized complex systems depends on a proper set of inputs to these subsystems, in such a way that the best stationary behavior of these systems is achieved. Despite several attempts for stabilizing the coupled multidisciplinary systems, the existing techniques still have their critical limitations and issues due to the unrealistic deterministic assumption in some cases as well as inability in handling large-scale systems. In this paper, we introduce a Bayesian framework using the combination of Bayesian optimization technique and Gibbs sampling method, which enables scalable, efficient and fast learning of the best input to achieve the best design of multidisciplinary systems. The accuracy and speed of the proposed framework will be demonstrated in numerical experiments using an aerodynamics- structures system and a mathematical example. |
18,633 | Please write an abstract with title: Design and characterization of a fast CMOS multiple linear array imager for nanosecond light pulse detections, and key words: Optical arrays, 1f noise, CMOS image sensors, Cameras, Image sensors, CMOS technology, Prototypes, Thermal sensors, Sensor phenomena and characterization, Sensor systems. Abstract: Active pixel sensors (APS) technology offers performance competitive with charge-coupled device technology, and it offers advantages in on-chip functionality, system power reduction, cost, and miniaturization. In this paper, we present the design and characterization of a fast CMOS APS imager for high-speed laser detections, which can replace streak cameras. It produces intensity information as a function of one spatial dimension and time (I=f(x,t)) from a pixel array with two spatial dimensions. The time information is obtained for the first prototype camera by delaying successively the integration phase for each pixel of the same row. The different noise sources of the APS sensors, such as shot noise due to the photo sensor, thermal noise, and flicker noise due to the readout transistors, and the photon shot noise are presented in order to determine the fundamental limits of the image sensor. The first prototype fast MOS imager (FAMOSI) consists of 64/spl times/64 active pixels. The simulation and experimental results show that a conversion gain of 6.73/spl plusmn/0.25 /spl mu/ V/e/sup -/ has been obtained with a noise level of 87/spl plusmn/3 e/sup -/ rms. The power consumption of the chip is 25 mW at 50 frames/s. The time resolution is 0.8 ns for this new concept camera. |
18,634 | Please write an abstract with title: Hybrid current-controlled VSI-IM drive, and key words: Current control, Automatic voltage control, Pulse width modulation inverters, Automation, Pulse inverters, Pulse modulation, Stators, Error correction, Strips, Automatic control. Abstract: Development of the hybrid type of control and the introduction of automation in Voltage Source Inverter switching control creates a basis for the evolution of Switching type Current Control in the direction of good compromise between Switching type Current Control and Pulse-Width Modulation features. The main premises in the design of the proposed hybrid current control are: (i) a stator current error plane in the d-q frame is divided into strip shaped regions for the selection of the controllers design (ii) stability is based on common quadratic Lyapunov function, (iii) the globally stable dynamics should guarantee uniform crossing of boundaries in the d-q frame, and (iv) superimposed automation supervises the non-Zenon VSI switching sequence. |
18,635 | Please write an abstract with title: Optimal Virtual Power Plant Operational Regime Under Reserve Uncertainty, and key words: Uncertainty, Dispatching, Real-time systems, Stochastic processes, Optimization, Renewable energy sources, Probability distribution. Abstract: Virtual power plant (VPP) has become an important resource for reserve provision owing to its fast-responding capability. In this paper, an optimal VPP operational regime considering reserve uncertainty is proposed, which includes a novel day-ahead offering strategy and a real-time dispatching model. At the day-ahead stage, the offering strategy gives the VPP’s price-dependent offers in the energy market under multiple uncertainties on market price, renewable generation, and calls of reserve deployment. A hybrid stochastic minimax regret (MMR) model is proposed to facilitate making offering decisions in the electricity market. At the real-time dispatching stage, generation scheduling can be realized based on the MMR criterion in an online fashion. To alleviate the intrinsic conservativeness of the dispatching model, a self-adaptive algorithm is also proposed to instantly modify the confidence bounds. The proposed regime is comprehensively tested through extensive case studies, which demonstrate the effectiveness of our method in obtaining operational decisions that are less conservative. |
18,636 | Please write an abstract with title: New Ideas and Methods of Coping Mechanism for Infectious Diseases Based on Big Data: A Critical Literature Review, and key words: Analytical models, Infectious diseases, Statistical analysis, Big Data, Inspection, Data models, Security. Abstract: Based on big data analysis, we discuss how to formulate an optimal coping mechanism for infectious diseases, especially major and emerging infectious diseases. First, by combining big data analysis and statistical analysis model and deducing whether the emerging disease is contagious, the strength of the contagion effect and the possible consequences, this study will determine whether the corresponding coping strategies should be implemented for infectious diseases, especially major and emerging infectious diseases. Secondly, according to the inspection results and actual situation, the optimal coping strategy is formulated to minimize the loss of life and property security of the country and the society by using the optimization principle and the objective management in management science. Finally, the statistical analysis method and the six sigma principle are combined to develop a feedback mechanism to evaluate whether the formulated coping strategies can achieve the expected results in practice. Our research has improved the research framework of infectious diseases in theory and provided scientific reference and experience for the major and emerging infectious diseases in practice for the future. |
18,637 | Please write an abstract with title: Overview of recent results from the triggered plasma opening switch experiment, and key words: Switches, Plasma devices, Plasma density, Magnetic fields, Plasma sources, Plasma measurements, Coils, Cathodes, Magnetic field measurement, Laboratories. Abstract: Summary form only given. The Triggered Plasma Opening Switch (TPOS) at Sandia National Laboratories is a unique device that exploits the high conductance and zero tensile strength of plasma. The purpose of the TPOS is to take the initial /spl sim/.8 MA (/spl sim/250 ns rise time) storage inductor current and deliver /spl sim/.5 MA, with a rise time of approximately 10 ns, to a load of about 5-10 /spl Omega/. Advantages of this configuration include low current jitter, power gain, low resistive voltage drop, and minimization of trigger input power as the result of using stages. First, plasma is introduced into the TPOS's A-K gap from plasma flash board sources. Current then flows through the plasma effectively shorting the A-K gap. Next, the switch is triggered when a pulse (50-150 ns rise time) is sent through a magnetic field coil. The energized coil gives rise to an axial magnetic field that pushes the plasma away from the cathode via the j/spl times/B force. (Clearly, this assumes that the magnetic field does not substantially penetrate the plasma, and that the plasma is azimuthally uniform.) Finally, the device triggers another similar stage in series with the first thus creating power amplification. The two stage design is novel, and this experiment is the first to implement magnetically triggered stages. In order for the switch to open correctly the plasma must travel sufficiently far away from the cathode. The plasma travels at the Alfven speed which is proportional to the magnetic field strength and inversely proportional to the density and mass of the plasma. Small percentages of water and oxygen exist, but the plasma is assumed to be dominantly composed of carbon. Therefore, since the mass and magnetic field are known, it is possible to infer the density by observing the opening speed. This is accomplished by measuring the plasmas location combined with the knowledge of the time dependent inductance and electron current. Specifically, if one assumes an axial field of /spl sim/1T, and an Alfven speed of approximately 1/spl times/10/sup 5/ to 1/spl times/10/sup 6/ m/s, this equates to a density of roughly 4/spl times/10/sup 21/ to 4/spl times/10/sup 19/ m/sup -3/. If the density is much higher, the switch may not open properly since the plasma's velocity is not sufficient to traverse the gap in the allotted time. Careful study of these characteristics is being carried out via side apparatus and magnetic field calculations. Hopefully, analysis leads to an ample characterization of the switch and ultimately a better understanding of the manner in which the two stages function. |
18,638 | Please write an abstract with title: Sensor Virtualization and Data Orchestration in Internet of Vehicles (IoV), and key words: Temperature distribution, Systems operation, Transportation, Tools, Safety, Virtualization, Monitoring. Abstract: The idea of the Internet of Vehicles (IoV) has begun with the emergence of the Internet of things (IoT) and big data. This concept of IoV allows for information exchange between vehicles-to-anything (V2X), such as other vehicles, pedestrians, and mobile devices to enhance road safety and traffic management. However, network operation and management become more complex with an increase in the number of IoV devices. Although virtualization is a key enabler to providing flexible and automated network management and network resources optimization for vehicular services, a continuous information gathering from roadside infrastructure is greatly required. To this end, in this paper, a system is proposed to exploit the potential of Mobile Edge Computing (MEC) and virtualization technologies to maintain the status of the underlying network on the intermediate layer. This would lead to enhanced data processing performance as well as the availability of pre-processed or real-time data of the vehicular network to the newly introduced services despite the disconnection periods of vehicles. |
18,639 | Please write an abstract with title: Graph Matching Via the Lens of Supermodularity, and key words: Linear programming, Optimization, Approximation algorithms, Bipartite graph, Indexes, Proteins, Approximation methods. Abstract: Graph matching, the problem of aligning a pair of graphs so as to minimize their edge disagreements, has received widespread attention owing to its broad spectrum of applications in data science. As the problem is NP–hard in the worst-case, a variety of approximation algorithms have been proposed for obtaining high quality, suboptimal solutions. In this article, we approach the task of designing an efficient polynomial-time approximation algorithm for graph matching from a previously unconsidered perspective. Our key result is that graph matching can be formulated as maximizing a monotone, supermodular set function subject to matroid intersection constraints. We leverage this fact to apply a discrete optimization variant of the minorization-maximization algorithm which exploits supermodularity of the objective function to iteratively construct and maximize a sequence of global lower bounds on the objective. At each step, we solve a maximum weight matching problem in a bipartite graph. Differing from prior approaches, the algorithm exploits the combinatorial structure inherent in the problem to generate a sequence of iterates featuring monotonically non-decreasing objective value while always adhering to the combinatorial matching constraints. Experiments on real-world data demonstrate the empirical effectiveness of the algorithm relative to the prevailing state-of-the-art. |
18,640 | Please write an abstract with title: Low-cost Smart Home Energy Management System based on Decentralized Real-Time Pricing, and key words: Bluetooth, decentralized markets, edge computing, real-time pricing, smart home energy management. Abstract: With ever increasing DERs and the associated volatility, top-down and centralized architectures fail. Reliance on communication systems drastically drops the resiliency of the system and exposes the systems to single points of failure. Demand management and smart load scheduling is key to managing wide variations in supply-demand ratios. Smart home devices often react to real-time prices performing arbitrage, demand optimization and smart scheduling. However, these devices rely on pricing mechanisms that need heavy centralized computation and low-latency communication infrastructure. The resulting smart home devices become quite expensive and unable to work in remote locations without connectivity. This paper proposes a first true integration of a low-cost hardware platform capable of edge intelligence, full AMI functionality and a decentralized transactional architecture that allows real-time prices to be generated locally based on system frequency. The smart home energy devices work with intermittent connectivity, by using mobile ad-hoc networks. The proposed platform shows great potential for consumer savings while implementing a highly resilient and fractal architecture. |
18,641 | Please write an abstract with title: An Optimized Rotor Design of Synchronous Reluctance Motor for Improved Torque Characteristics, and key words: Torque, Design methodology, Rotors, Stators, Permanent magnet motors, Electric vehicles, Finite element analysis. Abstract: Permanent Magnet Synchronous Motors (PMSM) are known to be preferred over other motors in electric vehicle (EV) application. However, due to over-dependence of expensive rare-earth magnets in these motors, lookout for alternate motors is on the anvil. In this paper, an optimized rotor design of Synchronous Reluctance Motor (SynRM) that is devoid of rare-earth materials is proposed in order to demonstrate its suitability in the EV category. Firstly, an analytical design method to determine the dimension of the stator and rotor structure of the SynRM is introduced. Without altering the stator design, an optimized design of rotor structure using the unit-less variables is proposed in this paper with the dual aim of maximizing the electromagnetic torque of the SynRM and minimizing torque ripple in it. Finite element analysis (FEA) is used to verify the analytical design and optimization of the rotor structure. The results of the SynRM design and optimization are presented to showcase the effectiveness of the envisaged design methodology. |
18,642 | Please write an abstract with title: Anomaly Detection Method for Aggregated Cellular Operator Data, and key words: Technological innovation, Machine learning algorithms, Sensitivity, Urban areas, Sociology, Statistics, Anomaly detection. Abstract: According to the research of the international agency “We are social” in April 2020, there are 5.16 billion mobile phone users in the world. This is 66% of the total population. This article is devoted to the search for anomalies in traffic data received from cellular operators. The first part of the article tells about what data is collected by cellular operators, how they are processed. A brief overview of methods for analyzing these data is provided. Further, the structure of the data that is collected from cellular operators by a special department of the city of Moscow is presented. In the second part of the article, methods for anomaly detection are analyzed, taking into account the specifics of the available data, and the advantages and disadvantages of its use are revealed. Then, a proprietary method for anomaly detection is proposed, which is based on the properties of traffic data. The work of the proposed method is demonstrated in several computational experiments. Further directions of work in the field of aggregated data analysis of cellular operators are proposed. |
18,643 | Please write an abstract with title: A Novel Structure and Route Algorithm for Hybrid DCN Network Based on ExCCC-DCN, and key words: Wireless communication, Data centers, Millimeter wave technology, Millimeter wave communication, Servers, Routing, Multicast algorithms. Abstract: With the rapid development of data center network (DCN) technology, researchers have cleverly combined wireless connection and wired DCN to form a new structure, hybrid data center network (HDCN). Exchanged Cube-Connected Cycles (ExCCC) has high scalability and relatively low construction cost and operation energy consumption, which is very suitable for the deployment of large-scale data center. In this paper a novel hybrid ExCCC-DCN structure is proposed by combining the communication characteristics of 60GHz millimeter-wave technology. The transformed hybrid network not only inherits the original structural characteristics of ExCCC-DCN structure, but also effectively reduces the network data traffic and improves the network throughput. We divide the hybrid ExCCC-DCN into several units (pods), and propose a new cluster-based multicast routing algorithm. Comparative experiments prove that the algorithm can effectively reduce the number of multicast links and improve the data throughput during multicast communication when constructing a multicast tree. |
18,644 | Please write an abstract with title: Fisheye Camera Calibration with Indoor 3D Calibration Field, and key words: Solid modeling, Three-dimensional displays, Cameras, Distortion, Mathematical models, Real-time systems, Calibration. Abstract: Cameras equipped with fisheye lenses have large distortion, and conventional camera calibration methods are no longer applicable. In this paper, we considered the radial distortion, tangential distortion, and thin lenses distortion of fisheye camera. we take the equidistant projection imaging model of fisheye camera as an example to derive the three-point common line constraint model under equidistant projection, namely spatial resection model of fisheye camera. Firstly, the fisheye camera spatial resection model is derived, the initial values of fisheye image radius and image center coordinates are calculated by curve fitting method, then the intrinsic parameters of fisheye lenses are calculated accurately by least square method, and finally spatial intersection is carried out to calculate the ground control point coordinates for verification. Our method takes a short time, is simple and satisfies the requirements of real-time calibration. |
18,645 | Please write an abstract with title: Independently Tunable Dual Band Antenna loaded with modified Split Ring Resonator with Circular Polarization Characteristics for Wireless Applications, and key words: Wireless sensor networks, Slot antennas, Split ring resonators, Resonant frequency, Dual band, Microstrip antennas, Bandwidth. Abstract: In this work, a circularly polarized (CP) dual band corner extended slot antenna loaded with a split ring resonator (SRR), which is modified in its structure, is presented. The antenna operates in two bands. The lower resonance frequency is obtained due to the slot dimension. The slot antenna is excited using them microstrip feed line. The corner extended slot antenna produce two degenerative modes which are require to obtain CP in the lower resonant frequency. An SRR is etched on a corner of the slot structure to obtain the upper resonance frequency. The slot antenna produce magnetic field which is axial in direction to modified SRR and excites it. To achieve CP in the upper frequency band, strips with asymmetric in nature are introduced in the SRR which creates equal magnitude with a 90° phase. The CP antenna with dual band characteristics is capable of tuning the resonance frequencies and polarization sense independently in each frequency band. The designed antenna is operated at 1.58 GHz and 1.95 GHz. The simulated results shows that the lower resonant frequency has a −10 dB impedance bandwidth from 1.47GHz-1.62GHz and upper resonant frequency from 1.84 GHz-2.08 GHz. A 200MHz of axial ratio (<3dB) bandwidth in the lower resonant frequency and 130MHz in the upper resonant frequency is obtained respectively. The simulated radiation efficiency of >75% is achieved in both bands. |
18,646 | Please write an abstract with title: Lifetime reduction due to insertion devices at BESSY II, and key words: Resonance, Intrusion detection, Tuned circuits, Frequency, Undulators, Optical distortion, Monitoring, Light sources, Optical losses, Optical sensors. Abstract: After closing insertion devices at BESSY II to smallest gaps beside appearance of a vertical tune-shift due to the natural focusing of the IDs, it is observed that beam lifetime is considerably reduced, up to 30 %. The reduction neither depends on machine tune nor on the settings of the four BESSY II harmonic sextupole circuits. Here measurements and analytical results to explain and cure this effect are presented. |
18,647 | Please write an abstract with title: Recognizing and responding to "bad smells" in extreme programming, and key words: Programming, Signal processing, Permission, Best practices, Software quality, Life testing, Project management, Books, Asset management, Contracts. Abstract: The agile software development process called Extreme Programming (XP) is a set of best practices which, when used, promises swifter delivery of quality software than one finds with more traditional methodologies. In this paper, we describe a large software development project that used a modified XP approach, identifying several unproductive practices that we detected over its two-year life that threatened the swifter project completion we had grown to expect. We have identified areas of trouble in the entire life cycle, including analysis, design, development, and testing. For each practice we identify, we discuss the solution we implemented to correct it and, more importantly, examine the early symptoms of those poor practices ("bad smells") that project managers, analysts, and developers need to look out for in order to keep an XP project on its swifter track. |
18,648 | Please write an abstract with title: A Computationally Cheap Error Estimator for the 3D Eddy Current Problem Using a MSFEM Approach Based on the A-Formulation, and key words: Three-dimensional displays, Estimation, Adaptive mesh refinement, Finite element analysis, Electromagnetic fields, Eddy currents. Abstract: The multiscale finite element method allows for the efficient calculation of eddy currents in laminated cores. This paper presents an error estimator which can be calculated on the same coarse mesh as the multiscale solution, making it computationally cheap while providing an accurate estimation of the error for both linear and nonlinear materials. Because of its local structure, this estimator enables adaptive mesh refinement. |
18,649 | Please write an abstract with title: Enabling information integration and workflows in a grid environment with automatic wrapper generation, and key words: Mesh generation, Data analysis, Data structures, Resource management, Databases, Computer science, Data engineering, Grid computing, Project management, Bioinformatics. Abstract: With a growing trend towards grid-based data repositories and data analysis services, scientific data analysis often involves accessing multiple data sources, and analyzing the data using a variety of analysis programs. One critical challenge in this, however, is that data sources often hold the same type of data in a number of different formats, and also, the formats expected and generated by various data analysis services are often distinct. We believe that the traditional approach for dealing with this problem, which is using hand-written wrappers, is not an effective and scalable solution for a grid environment. This paper presents a new approach, which involves generating wrappers automatically for enabling grid-based information integration and workflows. In this approach, a layout descriptor is used for describing the data format for each data source, as well as the input and output format for each tool or service. Efficient wrappers are then generated automatically for translation between any two data formats. Our design separates wrapper generation service from the wrapper execution. The wrapper generation service analyzes the layout descriptors and generates a WRAPINFO data structure. The wrapper comprises a set of application independent modules which take the WRAPINFO data structure as the input. We demonstrate our wrapper generation tool with two real case studies. Besides showing the effectiveness of our system, the experiments results from these two case studies show that the wrapper generation overhead is very small, automatically generated wrappers scale well to large datasets, and for the one case where this comparison was possible, the execution time of our wrapper was within 30% of that of a hand-written one. |
18,650 | Please write an abstract with title: Pymoo: Multi-Objective Optimization in Python, and key words: Optimization, Python, Tools, Task analysis, Data visualization, Evolutionary computation. Abstract: Python has become the programming language of choice for research and industry projects related to data science, machine learning, and deep learning. Since optimization is an inherent part of these research fields, more optimization related frameworks have arisen in the past few years. Only a few of them support optimization of multiple conflicting objectives at a time, but do not provide comprehensive tools for a complete multi-objective optimization task. To address this issue, we have developed pymoo, a multi-objective optimization framework in Python. We provide a guide to getting started with our framework by demonstrating the implementation of an exemplary constrained multi-objective optimization scenario. Moreover, we give a high-level overview of the architecture of pymoo to show its capabilities followed by an explanation of each module and its corresponding sub-modules. The implementations in our framework are customizable and algorithms can be modified/extended by supplying custom operators. Moreover, a variety of single, multi- and many-objective test problems are provided and gradients can be retrieved by automatic differentiation out of the box. Also, pymoo addresses practical needs, such as the parallelization of function evaluations, methods to visualize low and high-dimensional spaces, and tools for multi-criteria decision making. For more information about pymoo, readers are encouraged to visit: https://pymoo.org. |
18,651 | Please write an abstract with title: ROBUST AND EFFICIENT AGGREGATION FOR DISTRIBUTED LEARNING, and key words: Computer aided instruction, Distance learning, Computational modeling, Perturbation methods, Signal processing algorithms, Signal processing, Data models. Abstract: Distributed learning paradigms, such as federated and decentralized learning, allow for the coordination of models across a collection of agents, and without the need to exchange raw data. Instead, agents compute model updates locally based on their available data, and subsequently share the update model with a parameter server or their peers. This is followed by an aggregation step, which traditionally takes the form of a (weighted) average. Distributed learning schemes based on averaging are known to be susceptible to outliers. A single malicious agent is able to drive an averaging-based distributed learning algorithm to an arbitrarily poor model. This has motivated the development of robust aggregation schemes, which are based on variations of the median and trimmed mean. While such procedures ensure robustness to outliers and malicious behavior, they come at the cost of significantly reduced sample efficiency. This means that current robust aggregation schemes require significantly higher agent participation rates to achieve a given level of performance than their mean-based counterparts in non-contaminated settings. In this work we remedy this drawback by developing statistically efficient and robust aggregation schemes for distributed learning. |
18,652 | Please write an abstract with title: Investigations of Reed Switch Dynamics and Discharge Phenomena When Switching Intermediate and Heavy Loads, and key words: Switches, Blades, Power system dynamics, Contacts, Arc discharges, Magnetic flux, Elasticity, Current density, Hybrid power systems, Oscilloscopes. Abstract: Studies of reed switch dynamics and discharge phenomena when switching intermediate and large inductive currents are reported. The initial interactions of the reed dynamics and the dynamics of the electrical discharge in the contact gap during both opening and closing have been investigated. The investigations have been carried out using both oscilloscope studies and high speed photography of both dry and mercury-wetted reeds. Conclusions about the applications of reed switches for intermediate and large inductive currents are formulated. |
18,653 | Please write an abstract with title: Magnetically biased development of magnetographic images, and key words: Magnetic analysis, Permanent magnets, Analytical models, Computer simulation, Image analysis, Couplings, Performance analysis, Graphics, Magnetic heads, Microscopy. Abstract: The effect of magnetic bias fields on magnetographic development is studied. An analytical model of image field and associated force on toner particles is modified to incorporate bias fields of either direct or reverse polarity with respect to the dots magnetization. Using simple series expansions derived from the model, the main mechanisms of biased development are first identified. Based on the full model, 3-D computer simulations of the particles equilibrium on the imaged media, while exposed to bias fields of various intensity and polarity, are then provided and shown to reproduce quite reliably the real observed behavior. |
18,654 | Please write an abstract with title: Design of Partial-discharge-free Busbar for More-electric Aircraft Application with Low Pressure Condition, and key words: Partial discharges, Insulation, Inductance, Motor drives, Statistical analysis, Design methodology, Aerospace electronics. Abstract: This paper proposes an insulation design and optimization methodology for laminated busbars in more-electric aircraft (MEA) motor drive system. The design assumes that the converter works at around 11-km altitude with decompressed air pressure, which expedites partial discharge (PD) compared to it at sea-level. The trade-off between the insulation margin and power-loop stray inductance is revealed and optimized. By using the method, a busbar for a 450-kVA 3-level T-type neutral-point-clamped (3L-TNPC) converter is designed. Its partial discharge inception voltage (PDIV) is 43% higher than the rated voltage at the air pressure of 0.2 atm and 170% higher at normal air pressure. Busbar stray inductance of 12.0 nH is achieved, lower than published literature of 3-level converters. |
18,655 | Please write an abstract with title: Increasing utilization of the transmission grid requires new reliability criteria and comprehensive reliability assessment, and key words: Power system reliability, Risk management, Councils, Relays, Stress, Guidelines, Reliability engineering, Power engineering and energy, Systems engineering and theory, Power system planning. Abstract: Transmission grids are generally designed and operated in accordance with deterministic N-1 criteria. These have ensured adequate reliability in the past in large measure because of existing margins in the system. These margins have generally been sufficient to retain system reliability in the face of N-2 disturbances such as simultaneous outages of parallel lines caused by proximity or relay miss-operation. In the US, operating margins against events "beyond criteria" are being eroded by various means such as the use of parallel flow balancing devices, new generators placed to utilize the existing system, and pressure from transmission users to increase transfer limits. Flows on parallel paths are being equalized towards maximum capability making ever-larger numbers of N-2 events critical events, increasing the risk for serious trouble not recognized by present criteria. An effective means of recognizing and protecting against events not covered by N-1 criteria are needed. |
18,656 | Please write an abstract with title: Approaching optimal peer-to-peer overlays, and key words: Peer to peer computing, Algorithm design and analysis, Telecommunication network topology, Delay, Computer science, Computational modeling, Distributed computing, Costs, Network topology, NP-hard problem. Abstract: In unstructured peer-to-peer (P2P) systems, there exists a serious topology mismatch problem between physical and logical network. We first analyze the relationship between the property of the overlay and the corresponding message duplications incurred by queries in a given overlay, and prove that computing an optimal overlay with global knowledge is an NP-hard problem. Motivated by the analysis results, we design a distributed overlay optimization algorithm, THANCS, to attack topology mismatch. We demonstrate its performance by comprehensive simulations in dynamic environments. The proposed THANCS has three major strengths. First, it does not need any global knowledge. Second, its optimization convergent speed is fast. Third, it is orthogonal with other types of advanced search approaches. |
18,657 | Please write an abstract with title: A hybrid intelligent intrusion detection system to recognize novel attacks, and key words: Hybrid intelligent systems, Intrusion detection, Neural networks, Fuzzy neural networks, Computer networks, Engines, Computer architecture, Feedforward systems, Feedforward neural networks, Fuzzy reasoning. Abstract: We propose a hybrid intelligent intrusion detection system to recognize novel attacks. Current works in intrusion detection solve the anomaly detection and the misuse detection. The misuse detection cannot recognize the new types of intrusions; while the abnormal detection also suffers from the false alarms. The mechanism to detect new forms of attacks in the systems will be the most important issue for intrusion detection For this purpose, we apply the neural network approach to learn the attack definitions and the fuzzy inference approach to describe the relations of attack properties for recognition This study concentrates the focus on detecting distributed denial of service attacks to develop this system. Experiment results will verify the performance of the model. |
18,658 | Please write an abstract with title: Flexible Phased Array Shape Reconstruction, and key words: Phased arrays, Antenna measurements, Phase measurement, Shape, Dipole antennas, Array signal processing, Shape measurement. Abstract: Lightweight, flexible phased arrays enable new applications by dynamically changing shape during deployment and operation. However, these shape changes must be tracked and accounted for by changing the element excitation in order for the array to continue proper operation. We propose a framework for reconstructing the shape of a flexible phased array using only measurements of mutual coupling between the antennas in the array. The framework is demonstrated using a passive 2.5 GHz phased array and fixed to 8 different frames of known radii of convex and concave curvature. Our results show the ability to reconstruct shape to within ≈ 0.04λ position error, even in cases where the phased array is bent dramatically, without any advanced knowledge or additional information. The framework is modular and can be easily adapted to other phased array systems with different antennas, frequencies, and physical constraints. |
18,659 | Please write an abstract with title: Loop removal from LDPC codes, and key words: Parity check codes, Australia, Network address translation, Equations, Bipartite graph, Belief propagation, Iterative decoding, Telecommunication computing, Iterative algorithms, Degradation. Abstract: It is hypothesised that small loops in the graphical representations of low-density parity-check codes are detrimental to the code's performance. We demonstrate a procedure for removing such loops from the codes. An algorithm based on the code's adjacency matrix is used to locate unwanted loops, and then certain edges within the graph are exchanged to eliminate those loops (without simultaneously creating any others). This process can be repeated until there are no loops remaining with a size less than a particular limit. A comparison of some theoretical and experimental values for this limit is given. |
18,660 | Please write an abstract with title: Fuzzy Adaptive Sliding Mode Controller for A Chaotic System with Uncertainties and Disturbances, and key words: Asymptotic stability, Adaptive systems, Uncertainty, Simulation, Stability analysis, Trajectory, Sliding mode control. Abstract: In this paper, a fuzzy adaptive sliding mode control (FASMC) technique is used to control a new chaotic system. Using sliding mode control, a unique sliding manifold is considered, and the control law is achieved. The adaptive sliding mode control (ASMC) law is to make the system states track the desired signal and guarantee the property of asymptotical stability. In addition, the designed controller can control the uncertain chaotic features to the desired states stability, it can also reduce the chattering effect noticeably. The simulation results demonstrates the effectiveness and the accuarcy of the proposed control scheme. |
18,661 | Please write an abstract with title: Neural-network-based adaptive hybrid-reflectance model for 3-D surface reconstruction, and key words: Surface reconstruction, Image reconstruction, Shape, Neural networks, Brightness, Pixel, Computer vision, Light sources, Cost function, Supervised learning. Abstract: This paper proposes a novel neural-network-based adaptive hybrid-reflectance three-dimensional (3-D) surface reconstruction model. The neural network automatically combines the diffuse and specular components into a hybrid model. The proposed model considers the characteristics of each point and the variant albedo to prevent the reconstructed surface from being distorted. The neural network inputs are the pixel values of the two-dimensional images to be reconstructed. The normal vectors of the surface can then be obtained from the output of the neural network after supervised learning, where the illuminant direction does not have to be known in advance. Finally, the obtained normal vectors are applied to enforce integrability when reconstructing 3-D objects. Facial images and images of other general objects were used to test the proposed approach. The experimental results demonstrate that the proposed neural-network-based adaptive hybrid-reflectance model can be successfully applied to objects generally, and perform 3-D surface reconstruction better than some existing approaches. |
18,662 | Please write an abstract with title: A new analog oscillator electronics applied to a piezoelectric vibrating gyro, and key words: Oscillators, Vibration measurement, Gyroscopes, Equivalent circuits, Readout electronics, Drives, Angular velocity, Velocity measurement, Phase measurement, Circuit simulation. Abstract: This paper deals with a new analog oscillator applied to a piezoelectric vibratory gyroscope developed at ONERA. The equivalent circuit of the gyro and the readout electronics are presented. Then, the influence of phase and amplitude drifts of the drive mode vibration on the angular velocity measurements are discussed theoretically and experimentally. Finally, simulations of the new analog oscillator electronics including phase and amplitude control loops are shown. |
18,663 | Please write an abstract with title: Analysis of Secrecy Performance over Correlated η - µ Fading Channels, and key words: Correlation, Fading channels, Receiving antennas, Multicast communication, Monte Carlo methods. Abstract: In a multiple antenna network, correlation among the antennas tends to reduce the system capacity. In this paper, the effect of correlation on the secrecy performance over η - μ fading channel has been analyzed considering a multicast network in the presence of multiple eavesdroppers. Simple closed-form analytical expressions of the ergodic secrecy multicast capacity and the secure outage probability for multicasting are derived to numerically quantify the effect of correlation. The consequence of changing the number of receiving antennas on correlation has been observed and the secrecy performance of some commonly used channels like Gaussian channel, Rayleigh and Nakagami- m fading channels which can be found as a special case of the η - μ fading channel, have also been investigated. The derived expressions are finally verified through Monte-Carlo simulations. |
18,664 | Please write an abstract with title: Discriminative analysis of pixel difference towards picture quality prediction, and key words: Humans, Signal analysis, PSNR, Distortion measurement, Testing, Pixel, Error analysis, Decoding, Visual system, Image analysis. Abstract: This paper is devoted to discriminate pixel difference in the context of visual signal for picture quality prediction, according to human perceptual characteristics. The new quality predictor as the result of the analysis remedies one oversight in all the previous metrics, and proves to be more accurate and consistent in visual quality prediction then the best metrics in the VQEG tests. |
18,665 | Please write an abstract with title: Experimental comparison of the RZ-DPSK and NRZ-DPSK modulation formats, and key words: Modulation, Channel spacing, Optical transmitters, Wavelength measurement, Optical filters, Q factor, Differential quadrature phase shift keying, Power measurement, Signal to noise ratio, Optical noise. Abstract: The RZ-DPSK and NRZ-DPSK modulation formats were experimentally compared using installed undersea fiber links. Our results show a 1-1.5 dB RZ benefit with optimized RZ modulation depth for both 25-GHz and 33-GHz spaced channels. |
18,666 | Please write an abstract with title: Shape estimation of 3-D DNA molecules from stereo cryo-electron micro-graphs, and key words: Shape, DNA, Active contours, Skeleton, Transmission electron microscopy, Image reconstruction, Jacobian matrices, Ice, Degradation, Biomedical imaging. Abstract: We introduce a 3-D parametric active contour algorithm for the shape estimation of DNA molecules from stereo cryo-electron micrographs. We consider a 3-D filament (consisting of a B-spline skeleton and a specified radial profile) and match its projections with the micrographs using an optimization algorithm. To accelerate the evaluation of the projections, we approximate the global model locally by an elongated blob-like template that is designed to be projection-steerable. This means that the 2-D projections of the template at any 3-D orientation can be expressed as a linear combination of a few basis functions. Thus, the matching of the template projections is reduced to evaluating a weighted sum of the inner-products between the basis functions and the micrographs. We choose an internal energy term that penalizes the total curvature magnitude of the curve. We also use a constraint energy term that forces the curve to have a specified length. The sum of these terms along with the image energy obtained from the matching process is minimized using a conjugate-gradient algorithm. We validate the algorithm using real as well as simulated data. |
18,667 | Please write an abstract with title: Scattering by an infinite periodic array of thin conductors on a dielectric sheet, and key words: Scattering, Conductors, Dielectrics, Apertures, Integral equations, Boundary conditions, Magnetic fields, Geometry, Shape, Slabs. Abstract: The solution to the problem of scattering of a plane wave by an infinite periodic array of thin conductors on a dielectric slab is formulated in this paper. Numerical results are given as well as a comparison of this theory with experimental data. |
18,668 | Please write an abstract with title: Transmission Characteristics of Surface Waves in Defective Absorbing Layers, and key words: Surface waves, Optical surface waves, Surface impedance, Electromagnetics, Surface treatment, Electromagnetic scattering. Abstract: Magnetic loss materials have been extensively used as surface waves attenuation materials. Transmission characteristics of surface waves in defective absorbing layers were rarely reported. Herein, the transmission attenuation of surface waves on defective flexible magnetic loss-absorbing materials had been studied extensively. By comparison, the transmission performance of the surface wave on materials with defects was obviously deteriorated. The results demonstrated that the slot length was less than half the wavelength of the incident plane wave, the defect did not matter on the monostatic radar cross section. Once the length was larger than half wavelength, the scattering of the surface wave was obvious. Non-specular scattering occurs at the defects, causing an increase in the radar cross section. In order to further reduce the radar cross section caused by non-specular scattering, some effective repair schemes would be needed. |
18,669 | Please write an abstract with title: Scaling up SDM transmission capacity, and key words: Integrated circuits, Costs, Scalability, Transceivers, Space division multiplexing, Photonics. Abstract: We outline our vision to introduce ground-breaking programmable spatial multiplexing in novel transceivers capable of interfacing advanced multi-mode/core fibres with hundreds of spatial pathways and enabling scalability of all data pathways to reduce the cost and energy-consumption per bit. |
18,670 | Please write an abstract with title: A plated wire read only memory module, and key words: Wire, Read only memory, Voltage, Cables, Transistors, Ferrites, Anisotropic magnetoresistance, Magnetic films, Automatic control, Stability. Abstract: An electrically alterable read only memory module using NDRO plated wire cables has been designed to store the fixed programs of electronic exchange systems. The capacity of the memory system is 1080 kbits (4 modules) and the read cycle time 1.44 μs. The magnetic film of plated wire consists of five layers (Permalloy and Ni-Co films) on 0.1-mm-diameter Be-Cu wire. The 72-pair plated wires 50 m long are laminated between polyester tapes and are formed as a plated wire cable. A pair wire forms a bit (2 cross point/bit). The memory module consists of 16 memory planes stacked and involves 8192 33-bit words (270 336 bits) in total. An address has 8 words and is selected through a diode matrix built in the module. The plated wire cables are folded with no interconnection like the twister module. The digit (Id) and word current (Iw) operating ranges in this module are 68 to 92 mA and 270 to 320 mA, respectively. 5 mV is specified as an allowable minimum output voltage. The ambient temperature range of this module is from 10 to 40°C. The temperature coefficient of the output voltage is approximately 0.0065/°C. |
18,671 | Please write an abstract with title: The Comparison of Classification of Stress Level Related to Student's Menstrual Cycle Irregularities with Support Vector Machine and Decision Tree Algorithm, and key words: Support vector machines, Support vector machine classification, Human factors, Mental health, Classification algorithms, Information and communication technology, Decision trees. Abstract: Stress is a major problem that affects both physical and mental health. The menstrual cycle is one of the stress effects. Some of the studies only focused on their relationship. Menstrual cycle irregularity becomes more severe when the stress level is high. This study proposed the stress classification related to menstrual cycle by comparing SVM and Decision Tree. Start with data collection, preprocessing data (SMOTE), splitting dataset, classifying with SVM (kernel RBF) and Decision Tree (Gini index) and analyzing the result (confusion matrix). The results show that the accuracy was increased after adding the menstrual variable. This study found that the performance of SVM is better than the Decision Tree. The accuracy for the data without menstrual was 95.88% for SVM and 90.72% for the Decision Tree. But, when the menstrual variable was added the accuracy was 96.91% for SVM and 93.81% for the Decision Tree. The highest level was experienced by the final year with medium stress level. |
18,672 | Please write an abstract with title: A cryogenic open-cavity sapphire reference oscillator with low spurious mode density, and key words: Cryogenics, Stability, Microwave oscillators, Frequency measurement, Resonance, Laboratories, ISO standards, Dielectric losses, Q factor, Hydrogen. Abstract: In this paper, we describe the implementation of a microwave cryogenic sapphire oscillator (CSO) at the Laboratoire de Physique et Metrologie des Oscillateurs. In our realization we solved the problem of the spurious modes by operating the sapphire resonator in an open cavity. The CSO compared to a hydrogen maser demonstrates a frequency stability better than 3/spl times/10/sup -14/ at short term. Its long-term frequency instability of the order of 3/spl times/10/sup -12/ / day is limited by a random walk process. A first attempt to use this reference oscillator to characterize other signal sources is presented. |
18,673 | Please write an abstract with title: A Scalable Buffer Queue Sizing Algorithm for Latency Insensitive Systems, and key words: Throughput, Relays, Clocks, Optimization, Integrated circuit interconnections, Timing, System-on-chip. Abstract: Timing violations in high performance communication channels in system-on-chips (SoC) may occur in the late stages of the physical design process. To address that, latency insensitive systems (LISs) employ pipelining in the communication channels through the insertion of relay stations. Although the functionality of an LIS is robust with respect to the communication latencies, imbalances in relay station insertion may degrade the throughput of the system. While having a large number of buffer queues can eliminate such performance loss, the system may not have adequate area to accommodate these buffers. The problem of buffer queue sizing for maximizing throughput while meeting buffer area constraints has been solved using a mixed-integer linear program (MILP) formulation; however, such an approach is not scalable. In this work, we formulate the buffer queue sizing problem as a parameterized graph optimization problem where for every communication channel there is a parameterized edge with buffer counts as the edge weight. We then use a minimum cycle mean algorithm to determine from which edges buffers can be removed safely. Experimental results on large LISs suggest that the proposed approach is scalable. Moreover, quality of the solutions, in terms of the throughput and the size of buffer queues, is observed to be as good as that of the MILP-based approach. |
18,674 | Please write an abstract with title: Topology inference in the presence of anonymous routers, and key words: Network topology, Probes, Intelligent networks, Protocols, Optimization, Large-scale systems, Internet, Privacy. Abstract: Many topology discovery systems rely on traceroute to discover path information in public networks. However, for some routers, traceroute detects their existence but not their address; we term such routers anonymous routers. This paper considers the problem of inferring the network topology in the presence of anonymous routers. We illustrate how obvious approaches to handle anonymous routers lead to incomplete, inflated, or inaccurate topologies. We formalize the topology inference problem and show that producing both exact and approximate solutions is intractable. Two heuristics are proposed and evaluated through simulation. These heuristics have been used to infer the topology of the 6Bone, and could be incorporated into existing tools to infer more comprehensive and accurate topologies. |
18,675 | Please write an abstract with title: Stream-Based Active Learning with Multiple Kernels, and key words: Radio frequency, Hilbert space, Kernel, Task analysis. Abstract: Online multiple kernel learning (OMKL) has provided an attractive performance in nonlinear function learning tasks. Leveraging a random feature (RF) approximation, the major drawback of OMKL, known as the curse of dimensionality, has been recently alleviated. These advantages enable RF-based OMKL to be considered in practice. In this paper we introduce a new research problem, named stream-based active multiple kernel learning (AMKL), where a learner is allowed to label some selected data from an oracle according to a selection criterion. This is necessary in many real-world applications since acquiring a true label is costly or time-consuming. We theoretically prove that the proposed AMKL achieves an optimal sublinear regret $\mathcal{O}(\sqrt{T})$ as in OMKL with little labeled data, implying that the proposed selection criterion indeed avoids unnecessary label-requests. |
18,676 | Please write an abstract with title: GIC Effect on 400 kV Grid Transformers of Bangladesh Power System Network, and key words: Reactive power, Power transmission lines, Storms, Windings, Power grids, Sensor systems, Sensors. Abstract: Geomagnetically induced current (GIC) is lower in the low and middle latitude areas than in the auroral and sub-auroral areas. However, this may not be the case during intense solar storms. Long high voltage transmission lines may be severely affected by GIC. Using another grounded winding transformer, it enters the grid and back to the Earth through the grounded winding transformer. Transformers' reactive power consumption may also be significant if severe GMD occurs. The Bangladesh power system network is expanding. Several 400 kV transmission lines are in operation. The 400 kV grid of the Bangladesh power system is taken as a good test case for studying GIC effects in the low latitude region. This paper deals with the simulated response of the 400 kV power grid of BPSN during GMD events. |
18,677 | Please write an abstract with title: Enhancing BERT Representation With Context-Aware Embedding for Aspect-Based Sentiment Analysis, and key words: Bit error rate, Sentiment analysis, Task analysis, Feature extraction, Neural networks, Semantics, Encoding. Abstract: Aspect-based sentiment analysis, which aims to predict the sentiment polarities for the given aspects or targets, is a broad-spectrum and challenging research area. Recently, pre-trained models, such as BERT, have been used in aspect-based sentiment analysis. This fine-grained task needs auxiliary information to distinguish each aspect. But the input form of BERT is only a words sequence which can not provide extra contextual information. To address this problem, we introduce a new method named GBCN which uses a gating mechanism with context-aware aspect embeddings to enhance and control the BERT representation for aspect-based sentiment analysis. Firstly, the input texts are fed into BERT and context-aware embedding layer to generate BERT representation and refined context-aware embeddings separately. These refined embeddings contain the most correlated information selected in the context. Then, we employ a gating mechanism to control the propagation of sentiment features from BERT output with context-aware embeddings. The experiments of our model obtain new state-of-the-art results on the SentiHood and SemEval-2014 datasets, achieving a test F1 of 88.0 and 92.9 respectively. |
18,678 | Please write an abstract with title: Annotation-Efficient Learning for Medical Image Segmentation Based on Noisy Pseudo Labels and Adversarial Learning, and key words: Image segmentation, Training, Annotations, Shape, Biomedical imaging, Noise measurement, Deep learning. Abstract: Despite that deep learning has achieved state-of-the-art performance for medical image segmentation, its success relies on a large set of manually annotated images for training that are expensive to acquire. In this paper, we propose an annotation-efficient learning framework for segmentation tasks that avoids annotations of training images, where we use an improved Cycle-Consistent Generative Adversarial Network (GAN) to learn from a set of unpaired medical images and auxiliary masks obtained either from a shape model or public datasets. We first use the GAN to generate pseudo labels for our training images under the implicit high-level shape constraint represented by a Variational Auto-encoder (VAE)-based discriminator with the help of the auxiliary masks, and build a Discriminator-guided Generator Channel Calibration (DGCC) module which employs our discriminator’s feedback to calibrate the generator for better pseudo labels. To learn from the pseudo labels that are noisy, we further introduce a noise-robust iterative learning method using noise-weighted Dice loss. We validated our framework with two situations: objects with a simple shape model like optic disc in fundus images and fetal head in ultrasound images, and complex structures like lung in X-Ray images and liver in CT images. Experimental results demonstrated that 1) Our VAE-based discriminator and DGCC module help to obtain high-quality pseudo labels. 2) Our proposed noise-robust learning method can effectively overcome the effect of noisy pseudo labels. 3) The segmentation performance of our method without using annotations of training images is close or even comparable to that of learning from human annotations. |
18,679 | Please write an abstract with title: E-Voting Using Blockchain: A Systematic Literature Review, and key words: e-voting, blockchain, website 3.0. Abstract: The emergence of information technology has made many traditional systems start implementing technology, specifically voting systems. In addition, there is a lack of transparency and security that have been experienced in carrying out traditional voting. To support a transparent electronic-based voting system, decentralized blockchain technology is used. Therefore, transparency and security could be effectively implemented. This paper was created to provide insight to readers regarding the implementation of blockchain in e-voting systems. Based on 32 papers carried out by conducting a Systematic Literature Review (SLR) that have been collected and reviewed, this paper will discuss e-voting, blockchain, and blockchain implementation in e-voting systems. Performed SLR make it to identify the process of blockchain implementation in e-voting applications. |
18,680 | Please write an abstract with title: A 0.7-V MOSFET-only switched-opamp /spl Sigma//spl Delta/ modulator in standard digital CMOS technology, and key words: CMOS technology, Digital modulation, MOSFETs, MOS capacitors, MOS devices, Circuits, CMOS process, Threshold voltage, Boosting, Signal to noise ratio. Abstract: A 0.7-V MOSFET-only /spl Sigma//spl Delta/ modulator for voice band applications is presented. The second-order modulator is realized using a switched-opamp technique. All capacitors are realized using compensated MOS devices operated in the depletion region. A combination of parallel and series compensated depletion-mode MOSCAPs is used to obtain high area efficiency. The circuit is fabricated in a 0.18-/spl mu/m CMOS process. The only components used are standard n-MOS and p-MOS transistors with threshold voltages of approximately 400 mV. All transistors are operated within the supply voltage window of 0.7 V; voltage boosting techniques are not used. The active area is 0.082 mm/sup 2/. The modulator achieves 67-dB signal-to-noise-and-distortion ratio, 70-dB signal-to-noise ratio, and 75-dB dynamic range at 8-kHz signal bandwidth and consumes 80 /spl mu/W of power. |
18,681 | Please write an abstract with title: Deep-Learning-Based Signal Enhancement of Low-Resolution Accelerometer for Fall Detection Systems, and key words: Accelerometers, Power demand, Fall detection, Batteries, Signal resolution, Feature extraction, Degradation. Abstract: In the last two decades, fall detection (FD) systems have been developed as a popular assistive technology. To support long-term FD services, various power-saving strategies have been implemented. Among them, a reduced sampling rate is a common approach for an energy-efficient system in the real world. However, the performance of FD systems is diminished owing to low-resolution (LR) accelerometer signals. To improve the detection accuracy with LR accelerometer signals, several technical challenges must be considered, including mismatch of effective features and the degradation effects. In this work, a deep-learning-based accelerometer signal enhancement (ASE) model is proposed as a front-end processor to help typical LR-FD systems achieve better detection performance. The proposed ASE model based on a deep denoising convolutional autoencoder architecture reconstructs high-resolution (HR) signals from the LR signals by learning the relationship between the LR and HR signals. The results show that the FD system using support vector machine (SVM) and the proposed ASE model at an extremely low sampling rate (sampling rate < 2 Hz) achieved 97.34% and 90.52% accuracies in the SisFall and FallAllD data sets, respectively, while those without ASE models only achieved 95.92% and 87.47% accuracies in the SisFall and FallAllD data sets, respectively. The results also demonstrate that the proposed ASE mode can be suitably combined with deep-learning-based FD systems. |
18,682 | Please write an abstract with title: Demonstration of 100Gbit/s Real-Time Ultra High Definition Video Transmission Over Free Space Optical Communication Links, and key words: Power measurement, Atmospheric measurements, Urban areas, Streaming media, Real-time systems, Optical fiber communication. Abstract: The real-time FSO transmission of 100Gbps 4K-UHD video streams over 2.1km horizontal atmospheric link is successfully demonstrated. Results show that 100Gbps 4K-UHD video can be transmitted with negligible errors in 1000 seconds. |
18,683 | Please write an abstract with title: The N.2 System, and key words: Microcomputers, Runtime, Very large scale integration, Computational modeling, Microprocessors, Assembly, LAN interconnection, Fault detection, Programmable logic arrays, Graphics. Abstract: The N.2 System is described. N.2 is a simulation based design environment which is built upon the N.mPc System [1]. Major enhancements are presented, as well as a system overview. Areas covered include a hierarchical description facility, expanded port interconnection primitives, fault insertion/detection, a PLA description language, and increased use of graphics. |
18,684 | Please write an abstract with title: Perspective Algorithms in Control of Turbojet Engines, and key words: Microprocessors, Conferences, Safety, Large-scale systems, Reliability, Engines, Centralized control. Abstract: Turbojet engines are nowadays mostly controlled by full authority digital engine control (FADEC) systems using electronic engine control units. Microprocessor based control systems allow application of sophisticated control algorithms. The aim of the presentation is to show the state-of-the-art control systems and perspective algorithms based on integrated situational control methodology, which are aimed to increase the efficiency, reliability, and safety of operation of turbojet engines. Situational control is applied in this case in control and management of turbojet engines under all operational conditions including atypical ones using intelligent elements and strong integration with diagnostic systems. The concept of highly integrated control and diagnostic system is leading to a novel modular control framework with morphing structure and a degree of intelligence. It will be presented for application on general turbojet engines with specific implementation tested on a small turbojet engine in laboratory conditions as a proof of concept with positive results. These algorithms are designed as modular and robust with perspective applications in control of other large scale systems. |
18,685 | Please write an abstract with title: A New Fault-Tolerant Scheme for Switch Failures in Dual Active Bridge DC-DC Converter, and key words: Circuit faults, Fault tolerant systems, Fault tolerance, Bridge circuits, Switches, Transformers, DC-DC power converters. Abstract: The dual active bridge (DAB) dc-dc converter is widely investigated for applications such as solid-state transformers (SSTs), battery energy storage systems, and electric vehicle (EV) chargers. Failures in active devices of the DAB can cause reduced terminal voltages or uncontrollable currents eventually leading to converter disconnection. The above-mentioned consequences cannot be corrected by disabling the complementary switches of the faulty leg or reconfiguring the full-bridge (FB) DAB to a half-bridge (HB) DAB topology. In this article, a new fault-tolerant (FT) approach is proposed that works for both short-circuit (SC) or open-circuit (OC) failures in the active devices of the DAB dc-dc converter. Parallel combination of a fault-tolerant capacitor and a fast acting fuse, known as fault-tolerant unit, is connected in series with the primary as well as secondary of the transformer. Once the fault is detected, the output voltage is boosted to its pre-fault value through the incorporation of fault-tolerant capacitors along with variation in control parameters, ensuring the continuity of operation. The proposed post-fault reconfiguration scheme is validated experimentally using a 1 kW, 250 V DAB prototype. |
18,686 | Please write an abstract with title: Towards Deep Learning Assisted Autonomous UAVs for Manipulation Tasks in GPS-Denied Environments, and key words: Deep learning, Wireless communication, State feedback, Unmanned aerial vehicles, Task analysis, Grippers, Visual perception. Abstract: In this work, we present a pragmatic approach to enable unmanned aerial vehicle (UAVs) to autonomously perform highly complicated tasks of object pick and place. This paper is largely inspired by challenge-2 of MBZIRC 2020 and is primarily focused on the task of assembling large 3D structures in outdoors and GPS-denied environments. Primary contributions of this system are: (i) a novel computationally efficient deep learning based unified multi-task visual perception system for target localization, part segmentation, and tracking, (ii) a novel deep learning based grasp state estimation, (iii) a retracting electromagnetic gripper design, (iv) a remote computing approach which exploits state-of-the-art MIMO based high speed (5000Mb/s) wireless links to allow the UAVs to execute compute intensive tasks on remote high end compute servers, and (v) system integration in which several system components are weaved together in order to develop an optimized software stack. We use DJI Matrice-600 Pro, a hexrotor UAV and interface it with the custom designed gripper. Our framework is deployed on the specified UAV in order to report the performance analysis of the individual modules. Apart from the manipulation system, we also highlight several hidden challenges associated with the UAVs in this context. |
18,687 | Please write an abstract with title: Fitting ATE channels with scan chains: a comparison between a test data compression technique and serial loading of scan chains, and key words: Test data compression, Circuit testing, System testing, Performance evaluation, Automatic test pattern generation, Switches, Feeds, Decoding, Robots, Costs. Abstract: Since systems-on-chip (SoCs) keep on being more and more complex, test data compression has become essential to reduce test costs. In particular, a common technique for reducing test time is to use multiple scan chains. Nevertheless, this possibility is limited by the number of available ATE (automatic test equipment) channels. In this context, horizontal compression allows to fit the number of available ATE channels with the number of scan chains. But to achieve compression, these methods rely on the presence of don't care bits (X's) in the test sequences. Therefore, the length of these sequences is significantly greater than ones with fully specified bits. Conversely, serialization based methods allow to use fully specified test sequences, that are significantly smaller. This paper first presents a new method for horizontal test data compression and secondly proposes an answer to the question: is there really a benefit in terms of test application time (TAT) and test data volume of using compression instead of a simple serialization of test data?. |
18,688 | Please write an abstract with title: Analysis of Relationship Between Non-Identifiable TV Viewing History Data and Web Search Trends, and key words: TV, Television, TV viewing data, Big data, Viewer behavior, Visualization, Internet search, IoT. Abstract: Non-identifiable viewing history data can be collected from internet-connected TVs, and it is possible to grasp information such as IP addresses and viewing times without identifying individuals. Yomiuri Telecasting Corporation has collected data from approximately 3.5 million TV units, but it has been considered challenging to find new value from these data alone. Therefore, in this study, we combined non-identifiable viewing history data with internet search data, such as Google Trends, to analyze the impact of TV commercials on viewers’ internet search behavior. As a result, we found that as the number of commercial broadcasts increased, search behavior also increased, and we were able to identify the broadcast times of commercials that efficiently led to search behavior. |
18,689 | Please write an abstract with title: Time-of-Use-Aware Priority-Based Multi-Mode Online Charging Scheme for EV Charging Stations, and key words: Processor scheduling, Simulation, Urban areas, Pricing, Charging stations, Prediction algorithms, Electric vehicle charging. Abstract: Electric vehicle charging stations (EVCS) play a vital role in providing charging support to EV users. In order to facilitate users in terms of charging speed, two different charging modes (L2 and L3) are currently available at public charging stations. L3 mode provides quick charging with higher power, whereas L2 mode offers moderate charging speed with low power. The integration of an EVCS into the power grid requires coordinated charging strategies in order to reduce the electricity bill for a profitable operation. However, the effective utilization of the multi-mode charging strategy to serve the maximum number of EVs for a small charging station with limited charging capacity and spots is an open issue. To this end, we propose a priority-based online charging scheme, namely PBOS, which is based on real-time information and does not depend on future knowledge. The objective is to serve as many vehicles as possible in a day while fulfilling their charging requirements under a multi-mode EVCS setting and reducing the charging costs by utilizing the time-of-use pricing based demand response strategy. Simulation results show that the proposed algorithm can increase profit for EVCS by up to 42% with a 20% lower rejection rate when compared with other schemes. |
18,690 | Please write an abstract with title: Gallium-diffused ridge waveguides in sapphire, and key words: Optical waveguides, Waveguide transitions, Optimized production technology, Optical device fabrication, Optical planar waveguides, Planar waveguides, Glass, Titanium, Waveguide lasers, Refractive index. Abstract: Summary form only given. It has been shown that Ga:sapphire channel waveguides with small mode sizes may be realized by diffusion and ion-beam milling. Co-doping of sapphire with titanium and gallium is expected to lead to waveguide lasers with improved performance, as the gallium-diffused waveguide yields a small mode size for low pump power threshold and the titanium concentration may be flexibly adjusted for optimum laser operation. The realization of a passive waveguide technology in sapphire is also expected to allow the integration of passive devices for wavelength selection and tuning gain sections locally doped with titanium. |
18,691 | Please write an abstract with title: Disturbed Augmentation Invariance for Unsupervised Visual Representation Learning, and key words: Unsupervised learning, self-supervised learning, representation learning, contrastive learning, convolutional neural network. Abstract: Contrastive learning has gained great prominence recently, which achieves excellent performance by simple augmentation invariance. However, the simple contrastive pairs suffer from lacking of diversity due to the mechanical augmentation strategies. In this paper, we propose Disturbed Augmentation Invariance (DAI for abbreviation), which constructs disturbed contrastive pairs by generating appropriate disturbed views for each augmented view in the feature space to increase the diversity. In practice, we establish a multivariate normal distribution for each augmented view, whose mean is corresponding augmented view and covariance matrix is estimated from its nearest neighbors in the dataset. Then we sample random vectors from this distribution as the disturbed views to construct disturbed contrastive pairs. In order to avoid extra computational cost with the increase of disturbed contrastive pairs, we utilize an upper bound of the trivial disturbed augmentation invariance loss to construct the DAI loss. In addition, we propose Bottleneck version of Disturbed Augmentation Invariance (BDAI for abbreviation) inspired by the Information Bottleneck principle, which further refines the extracted information and learns a compact representation by additionally increasing the variance of the original contrastive pair. In order to make BDAI work effectively, we design a statistical strategy to control the balance between the amount of the information shared by all disturbed contrastive pairs and the compactness of the representation. Our approach gets a consistent improvement over the popular contrastive learning methods on a variety of downstream tasks, e.g. image classification, object detection and instance segmentation. |
18,692 | Please write an abstract with title: Silver-Sintering for Die-Attachment in HT-Sensor Applications – Materials and Reliability, and key words: Substrates, Silicon, Steel, Metallization, Temperature sensors, Ceramics, Photomicrography. Abstract: This work will give an overview of silver-sintered joints between typical materials and different surface metallizations for sensor applications. A pressure-less, a low-pressure and a standard pressure-assisted paste were compared during the investigation. Using shear tests and micrographs, the feasibility of the sinter process of silicon dies on silicon, ceramic and steel substrates was demonstrated. The strength and reliability of these joints was tested using high temperature storage for 24 h up to 300 °C and thermal cycling between 50 C and 250 °C. For the low-pressure paste, the stability increased after a storage of 200 °C but dropped at temperatures above. During the cycling, all of the pastes showed a response to the large CTE-mismatch of the silicon dies on the steel substrate. The pressure-assisted paste showed the most stable results with only a slight drop in the shear strength after 200 cycles on the steel substrate. For temperatures up to 300 °C and cycling on the ceramic and silicon substrate, the shear strength remained on the same level. |
18,693 | Please write an abstract with title: Simulation of magnetic properties versus temperature for RE-TM based amorphous alloys, and key words: Magnetic properties, Temperature, Amorphous materials, Atomic measurements, Neodymium, Magnetic moments, Iron alloys, Magnetic anisotropy, Electrons, Micromagnetics. Abstract: This paper presents two approaches for modeling the magnetic properties of some Fe-Nd-based alloys. Both micromagnetic models used in the paper give results which are in qualitative agreement with the experimental observations. This study confirms the hypothesis that the iron clusters play a key role in defining the magnetic properties of the alloys and their temperature dependence. |
18,694 | Please write an abstract with title: The GDST Frame and Inverse Transforms, and key words: GDST, time-frequency analysis, frame, invert transform, Discrete Stockwell Transform. Abstract: Generalization of the Discrete Stockwell Transform (GDST) provides a constructive framework to unify and expand various existing discrete Stockwell transforms. Under the developed framework, we are able to flexibly adjust the time/frequency sampling resolution, tailor the amount of information redundancy and computational complexity, reserve the absolutely reference phases as well. In this paper, we propose an admissible condition and prove that any GDST satisfy this condition will constitute a frame in the Hilbert Space, which guides us to derive the explicit formula for the inverse of GDST through finding its canonical dual frame. |
18,695 | Please write an abstract with title: A Learning Distributed Gaussian Process Approach for Target Tracking over Sensor Networks, and key words: Wireless sensor networks, Target tracking, Uncertainty, Scalability, Gaussian processes, Numerical models, Trajectory. Abstract: Tracking manoeuvring targets often relies on complex models with non-stationary parameters. Gaussian process (GP) based model-free methods can achieve accurate performance in a data-driven manner but face scalability challenges. Aiming to address such challenges, this paper proposes a distributed GP-based tracking approach able to learn the kernel hyperparameters in an online manner, to improve the tracking performance and scalability. It caters to the inherent distributed feature of sensor networks and does not need measurements to be transmitted among sensors for target states predictions. Theoretical upper confidence bounds about the tracking error are derived within the regret bound setting. Through this theoretical analysis, the tracking error per time step is upper bounded as a function of predictive variances from local sensors. The theoretical results are supported by simulation based ones over a case study for tracking over wireless sensor networks. With evaluation on challenging target trajectories, a comparison on state-of-the-art centralised and distributed GP approaches, numerical results demonstrate that the proposed approach achieves competitively high and robust tracking performance. |
18,696 | Please write an abstract with title: A 5-GHz monolithic silicon bipolar down-converter with a 3.2-dB noise figure, and key words: Silicon, Noise figure, Wireless LAN, Linearity, Inductors, Low-noise amplifiers, Performance gain, Impedance matching, Amplitude modulation, Radio frequency. Abstract: A monolithic 5-GHz down-converter consisting of a low noise amplifier (LNA) and a double-balanced mixer was designed using a 46-GHz-f/sub T/ silicon bipolar process. The down-converter exhibits a SSB noise figure as low as 3.2 dB, a 24-dB power gain, and an input compression point of -23 dBm. It was assembled in a 4 /spl times/ 4 mm = low-cost QFN 16-lead plastic package and draws only 18 mA from a 3-V power supply. |
18,697 | Please write an abstract with title: Fully Distributed Adaptive Event-Triggered Leaderless Consensus Protocol for Physically Interconnected Multi-agent Systems, and key words: Protocols, Multi-agent systems, Artificial neural networks, Adaptive control, Graph theory, Industries. Abstract: In this study, the leaderless consensus issue is considered for general linear multi-agent systems with physically interconnected network under an undirected connected graph. Based on the local states information feedback, a novel fully distributed controller that uses adaptive event-triggered protocol is developed, which can ensure that every agent achieve consensus without requiring continuous communication and global network information. Meanwhile, it is proved that the Zeno behavior isn't exhibited by demonstrating the lower-bound of minimum inter-event interval is strictly positive under the proposed control protocol. Compared to the existing related papers, the salient feature of this paper is that both physically interconnected network and communication interconnected network of the multi-agent systems are considered on the premise that the designed event-triggered consensus protocol are fully distributed, asynchronous. Therefore, this makes the systems are more comprehensive and practical. Finally, the performance and effectiveness of the protocol are displayed by a example. |
18,698 | Please write an abstract with title: Gain and bandwidth enhancement of a 2.4 GHz singly-fed cross-aperture coupled patch antenna, and key words: Bandwidth, Patch antennas, Impedance, Microstrip antennas, Polarization, Antenna measurements, Permittivity, Frequency, Apertures, Artificial satellites. Abstract: This paper presents techniques to improve the gain and bandwidths of a singly-fed cross-aperture coupled patch antenna at 2.4 GHz for circular polarisation. The experimental and simulated results on the antenna are presented. The antenna has a gain bandwidth of 15.5% with a mean gain of 9.32 dBic. The impedance bandwidth (VSWR/spl les/2) and 3 dB axial ratio bandwidth are obtained as 14.4% and 2.7%, respectively. The measured cross-polarisation, front-to-back ratio and half-power beamwidths are also examined. |
18,699 | Please write an abstract with title: Improved MIMO Modeling and Enhanced Transient Performance of Phase-Locked Loop During Grid Fault, and key words: Phase locked loops, MIMO communication, Voltage control, Couplings, Power system harmonics, Power system dynamics, Harmonic analysis. Abstract: A phase-locked loop (PLL) is commonly used in grid-connected power converter for synchronization. A single input single output (SISO) linear model of PLL with the phase angle of the point of common coupling (PCC) voltage as input and the estimated phase angle as the output is generally used in the PLL analysis and design. However, an undesirable coupling between the magnitude and phase of the input voltage is present when a filtering stage is incorporated before the control loop, which a SISO model cannot capture, and could result in a significant disturbance in the PLL estimated phase during grid faults. This paper proposes a generalized multi-input multi-output (MIMO) linear model that captures the complete PLL dynamics during symmetrical faults for a PLL equipped with any prefilter. Furthermore, a compensation method that decouples the magnitude dynamics of the input voltage from the phase dynamics is proposed in this paper. The proposed compensation improves the PLL's phase tracking performance by ensuring that the prefiltered PLL acts only on the PCC voltage phase changes. A vital application of the proposed compensation method for PLL is during a grid fault case, wherein the converters are expected to contribute to the fault current, which requires an accurate measurement of the PCC voltage phase. The compensation method's effectiveness is demonstrated using power hardware in the loop simulation of a hardware voltage source converter interfaced to a distribution system simulated in real-time. |
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