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A Nonmonotone Projection Method for Constrained System of Nonlinear Equations

MATHEMATICAL PROBLEMS IN ENGINEERING 2017年第1期2017卷 1-5页

作者： Dang, Yazheng Liu, Wenwen Univ Shanghai Sci & Technol Sch Management 334 Jungong Rd Shanghai 200093 Peoples R China

This paper deals with the nonmonotone projection algorithm for constrained nonlinear equations. For some starting points, the previous projection algorithms for the problem may encounter slow convergence which is related to the monotone behavior of the iterative sequence as well as the iterative direction. To circumvent this situation, we adopt the nonmonotone technique introduced by Dang to develop a nonmonotone projection algorithm. After constructing the nonmonotone projection algorithm, we show its convergence under some suitable condition. Preliminary numerical experiment is reported at the end of this paper, from which we can see that the algorithm we propose converges more quickly than that of the usual projection algorithm for some starting points.

关键词： NONMONOTONIC logic NONLINEAR equations STOCHASTIC convergence computer algorithms NUMERICAL analysis

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Data-Driven Modeling of a Commercial Photovoltaic Microinverter

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MODELLING AND SIMULATION IN ENGINEERING 2018年第1期2018卷 1-11页

作者： Abbood, Hayder D. Benigni, Andrea Univ South Carolina Columbia SC 29208 USA

We present a data-driven modeling (DDM) approach for static modeling of commercial photovoltaic (PV) microinverters. The proposed modeling approach handles all possible microinverter operating modes, including burst mode. No prior knowledge of internal components, structure, and control algorithm is assumed in developing the model. The approach is based on Artificial Neural Network (ANN) and Fast Fourier Transform (FFT). To generate the data used to train the model, a Power Hardware in the Loop (PHIL) approach is applied. Instantaneous inputs-outputs data are collected from the terminals of a commercial PV microinverter at time domain. Then, the collected data are converted to the frequency domain using Fast Fourier Transform(FFT). The ANNs that are the core of the DDM are developed in frequency domain. The outputs of the ANNs are then converted back to time domain for validation and use in system level simulation. The comparison between measured and simulated data validates the performance of the presented approach.

关键词： Polydnaviridae TIME-DOMAIN simulated data static models Artificial neural networks burst mode Fast Fourier transform Frequency-domain analysis system level computer algorithms

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Suppression of pileup events by pulse shape discrimination using the Gatti filter

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INSTRUMENTS AND EXPERIMENTAL TECHNIQUES 2017年第2期60卷 188-192页

作者： Verbitsky, S. S. Emokhonov, V. N. Lapik, A. M. Rusakov, A. V. Tikanov, M. A. Tselebrovsky, A. N. Shilyaev, A. A. Russian Acad Sci Inst Energy Problems Chem Phys Moscow 119334 Russia Russian Acad Sci Inst Nucl Res Moscow 117312 Russia

An algorithm is proposed that provides reliable discrimination between neutrons and gamma rays in mixed fields and reduces the influence of gamma-ray pileups at a slight complication of the hardware and the algorithms. The algorithm uses a stepwise Gatti filter for two detection periods (a short period of several hundreds of nanoseconds and a long period of a few microseconds) for the same event. Using mathematical simulation of 12000 neutron and gamma-ray events, it has been demonstrated that at particle energies of similar to 128 keV in the electron equivalent (ee), the algorithm suppresses gamma-ray pileups on a level of 10(4) with a neutron loss of only approximately 1%. Due to the proposed algorithm, the counting ability is of the order of 10(5) events/s.

关键词： PULSE shaping (Digital communications) computer algorithms ELECTRONS computer programming ELECTRONIC pulse techniques

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Approach to Neonates and Young Infants with Fever without a Source Who Are at Risk for Severe Bacterial Infection

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MEDIATORS OF INFLAMMATION 2018年第1期2018卷 1-11页

作者： Esposito, Susanna Rinaldi, Victoria Elisa Argentiero, Alberto Farinelli, Edoardo Cofini, Marta D'Alonzo, Renato Mencacci, Antonella Principi, Nicola Univ Perugia Dept Surg & Biomed Sci Pediat Clin Perugia Italy Univ Perugia Dept Med Microbiol Unit Perugia Italy Univ Milan Pediat Milan Italy

Introduction. Among neonates and infants <3 months of age with fever without a source (FWS), 5% to 15% of cases are patients with fever caused by a serious bacterial infection (SBI). To favour the differentiation between low- and high-risk infants, several algorithms based on analytical and clinical parameters have been developed. The aim of this review is to describe the management of young infants with FWS and to discuss the impact of recent knowledge regarding FWS management on clinical practice. Materials and Methods. PubMed was used to search for all of the studies published over the last 35 years using the keywords: "fever without source" or "fever of unknown origin" or "meningitis" or "sepsis" or "urinary tract infection" and "neonate" or "newborn" or "infant <90 days of life" or "infant <3 months". Results and Discussion. The selection of neonates and young infants who are <3 months old with FWS who are at risk for SBI remains a problem without a definitive solution. The old Rochester criteria remain effective for identifying young infants between 29 and 60 days old who do not have severe bacterial infections (SBIs). However, the addition of laboratory tests such as C-reactive protein (CRP) and procalcitonin (PCT) can significantly improve the identification of children with SBI. The approach in evaluating neonates is significantly more complicated, as their risk of SBIs, including bacteremia and meningitis, remains relevant and none of the suggested approaches can reduce the risk of dramatic mistakes. In both groups, the best antibiotic must be carefully selected considering the clinical findings, the laboratory data, the changing epidemiology, and increasing antibiotic resistance of the most common infectious bacteria.

关键词： BACTERIAL disease risk factors NEONATAL diseases FEVER ANTIBIOTICS computer algorithms

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Filtered Medial Surface Based Approach for 3D Collision-Free Path Planning Problem

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JOURNAL OF ROBOTICS 2018年第6-3期2018卷 4676720-4676720页

作者： Benzaid, Karima Marie, Romain Mansouri, Noura Labbani-Igbida, Ouiddad Univ Freres Mentouri Constantine 1 LARC Lab Constantine Algeria Univ Limoges UMR CNRS 7252 X Lim Inst Limoges France

This paper introduces an original 3D path planning approach for Unmanned Aerial Vehicle (UAV) applications. More specifically, the core idea is to generate a smooth and collision-free path with respect to the vehicle dimension. Given a 3D grid representation of the environment, the Generalized Voronoi Graph (GVG) is first approximated using a filtered medial surface (FMS) algorithm on the corresponding navigable space. Based on an efficient pruning criterion, the produced FMS excludes GVG portions corresponding to narrow passages unfitting safe UAV navigation constraints, and thus it defines a set of guaranteed safe trajectories within the environment. Given a set of starting and destination coordinates, an adapted A-star algorithmis then applied to compute the shortest path on the FMS. Finally, an optimization process ensures the smoothness of the final path by fitting a set of 3D Bezier curves to the initial path. For a comparative study, the A-star algorithm is applied directly on the input environment representation and relevant comparative criteria are defined to assert the proposed approach using simulation results.

关键词： Robotic path planning Drone aircraft computer algorithms Computational complexity Metaheuristic algorithms

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It's Not the Algorithm, It's the Data

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COMMUNICATIONS OF THE ACM 2017年第2期60卷 21-23页

作者： Kirkpatrick, Keith LLC Res & Consulting 4K Lynbrook NY USA

The article discusses the impact of biased data on risk assessment and predictive policing. Topics include the use of risk-based assessment tools such as COMPAS (Correctional Offender Management Profiling for Alternative Sanctions) to aid U.S. states in sentencing criminals, concerns regarding the possibility of computerized risk-assessment algorithms penalizing racial minorities by overpredicting their likelihood of recidivism, and the use of poverty, postal codes, and employment status by COMPAS.

关键词： Risk assessment computer algorithms Predictive policing Race discrimination in criminal justice administration Criminal statistics -- United States

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Shunt Active Power Filter Based on Proportional Integral and Multi Vector Resonant Controllers for Compensating Nonlinear Loads

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JOURNAL OF ELECTRICAL AND computer ENGINEERING 2018年第Pt.2期2018卷 1312064.1-1312064.11页

作者： Ye, Sen Zhang, Youbing Xie, Luyao Lu, Haiqiang Zhejiang Univ Technol Coll Informat Engn Hangzhou Zhejiang Peoples R China Jiaxing Heng Chuang Elect Equipment Co Ltd Jiaxing Peoples R China

The current tracking control strategy determines the compensation performance of shunt active power filter (SAPF). Due to inadequate compensation of the main harmonic by traditional proportional integral (PI) control, a control algorithm based on PI and multi vector resonant (VR) controllers is proposed to control SAPF. The mathematical model of SAPF is built, and basic principle of VR controller is introduced. Under the synchronous reference frame, the proposed control method based on pole zero cancellation is designed, which narrows the order of the control system and improves the system dynamic response and the control accuracy., en the feasibility of the method is demonstrated by analyzing the closed loop frequency characteristics of the system. Finally, the simulation and experimental results are carried out to verify the performance of the proposed method.

关键词： Poles and zeros power filters control systems Proportional integral Variable reluctance Shunts (electrical) shunt Control Methods nonlinear load computer algorithms undercompensation control accuracy active power filter Controllers

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Approximating hidden chaotic attractors via parameter switching

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CHAOS 2018年第1期28卷 013127-013127页

作者： Danca, Marius-F. Kuznetsov, Nikolay V. Chen, Guanrong Avram Iancu Univ Cluj Napoca Dept Math & Comp Sci Cluj Napoca Romania Romanian Inst Sci & Technol Cluj Napoca Romania St Petersburg State Univ Dept Appl Cybernet St Petersburg Russia Univ Jyvaskyla Dept Math Informat Technol Jyvaskyla 40014 Finland City Univ Hong Kong Dept Elect Engn Hong Kong Hong Kong Peoples R China

In this paper, the problem of approximating hidden chaotic attractors of a general class of nonlinear systems is investigated. The parameter switching (PS) algorithm is utilized, which switches the control parameter within a given set of values with the initial value problem numerically solved. The PS-generated attractor approximates the attractor obtained by averaging the control parameter with the switched values, which represents the hidden chaotic attractor. The hidden chaotic attractors of a generalized Lorenz system and the Rabinovich-Fabrikant system are simulated for illustration. Published by AIP Publishing.

关键词： CHAOS theory APPROXIMATION theory ATTRACTORS (Mathematics) SWITCHING systems (Telecommunication) computer algorithms NONLINEAR systems

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A Triangular Personalized Recommendation Algorithm for Improving Diversity

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DISCRETE DYNAMICS IN NATURE AND SOCIETY 2018年第1期2018卷 1-11页

作者： Cai, Biao Yang, Xiaowang Huang, Yusheng Li, Hongjun Sang, Qiang Chengdu Univ Technol Coll Informat Sci & Technol Dept Digital Media Technol Chengdu Sichuan Peoples R China Chengdu Univ Technol Coll Informat Sci & Technol Chengdu Sichuan Peoples R China

Recommendation systems are used when searching online databases. As such they are very important tools because they provide users with predictions of the outcomes of different potential choices and help users to avoid information overload. They can be used on e-commerce websites and have attracted considerable attention in the scientific community. To date, many personalized recommendation algorithms have aimed to improve recommendation accuracy from the perspective of vertex similarities, such as collaborative filtering and mass diffusion. However, diversity is also an important evaluation index in the recommendation algorithm. In order to study both the accuracy and diversity of a recommendation algorithm at the same time, this study introduced a "third dimension" to the commonly used user/product two-dimensional recommendation, and a recommendation algorithm is proposed that is based on a triangular area (TR algorithm). Hie proposed algorithm combines the Markov chain and collaborative filtering method to make recommendations for users by building a triangle model, making use of the triangulated area. Additionally, recommendation algorithms based on a triangulated area are parameter-free and are more suitable for applications in real environments. Furthermore, the experimental results showed that the TR algorithm had better performance on diversity and novelty for real datasets of MovieLens-100K and MovieLens-lM than did the other benchmark methods.

关键词： RECOMMENDER systems (Information filtering) DATABASE searching ONLINE databases SCIENTIFIC community computer algorithms MARKOV processes

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An Application of a Model-Prediction-Based Reference Modification Algorithm to Engine Air Path Control

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SAE INTERNATIONAL JOURNAL OF COMMERCIAL VEHICLES 2017年第1期10卷 291-298页

作者： Shirai, Hayato Nakada, Hayato Matsunaga, Akio Tominaga, Hiroyuki Toyota Motor Co Ltd Shizuoka Japan

In real-world automotive control, there are many constraints to be considered. In order to explicitly treat the constraints, we introduce a model-prediction-based algorithm called a reference governor (RG). The RG generates modified references so that predicted future variables in a closed-loop system satisfy their constraints. One merit of introducing the RG is that effort required in control development and calibration would be reduced. In the preceding research work by Nakada et al., only a single reference case was considered. However, it is difficult to extend the previous work to more complicated systems with multiple references such as the air path control of a diesel engine due to interference between the boosting and exhaust gas recirculation (EGR) systems. Moreover, in the air path control, multiple constraints need to be considered to ensure hardware limits. Hence, it is quite beneficial to cultivate RG methodologies to deal with multiple references and constraints. In this paper, we develop the RG algorithm based on gradient descent method to allow for multiple references and constraints. We demonstrate the effectiveness of the presented RG algorithm in a transient driving cycle experiment using a real engine, in which constraints are enforced on maximal boost pressure, turbine speed, compressor surge and maximal and minimal EGR rates. The experiment implies that we have expanded the applicability of an RG to system with multiple references compared to the previous work for only a single reference.

关键词： AUTOMOBILE engines computer algorithms EXHAUST gas recirculation AUTOMOBILE emissions AUTOMOBILES & the environment

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