Named data networking(NDNs)is an idealized deployment of information-centric networking(ICN)that has attracted attention from scientists and scholars worldwide.A distributed in-network caching scheme can efficiently r...Named data networking(NDNs)is an idealized deployment of information-centric networking(ICN)that has attracted attention from scientists and scholars worldwide.A distributed in-network caching scheme can efficiently realize load balancing.However,such a ubiquitous caching approach may cause problems including duplicate caching and low data diversity,thus reducing the caching efficiency of NDN routers.To mitigate these caching problems and improve the NDN caching efficiency,in this paper,a hierarchical-based sequential caching(HSC)scheme is proposed.In this scheme,the NDN routers in the data transmission path are divided into various levels and data with different request frequencies are cached in distinct router levels.The aim is to cache data with high request frequencies in the router that is closest to the content requester to increase the response probability of the nearby data,improve the data caching efficiency of named data networks,shorten the response time,and reduce cache redundancy.Simulation results show that this scheme can effectively improve the cache hit rate(CHR)and reduce the average request delay(ARD)and average route hop(ARH).展开更多
In this study,a completely different approach to optimization is introduced through the development of a novel metaheuristic algorithm called the Barber Optimization Algorithm(BaOA).Inspired by the human interactions ...In this study,a completely different approach to optimization is introduced through the development of a novel metaheuristic algorithm called the Barber Optimization Algorithm(BaOA).Inspired by the human interactions between barbers and customers,BaOA captures two key processes:the customer’s selection of a hairstyle and the detailed refinement during the haircut.These processes are translated into a mathematical framework that forms the foundation of BaOA,consisting of two critical phases:exploration,representing the creative selection process,and exploitation,which focuses on refining details for optimization.The performance of BaOA is evaluated using 52 standard benchmark functions,including unimodal,high-dimensional multimodal,fixed-dimensional multimodal,and the Congress on Evolutionary Computation(CEC)2017 test suite.This comprehensive assessment highlights BaOA’s ability to balance exploration and exploitation effectively,resulting in high-quality solutions.A comparative analysis against twelve widely known metaheuristic algorithms further demonstrates BaOA’s superior performance,as it consistently delivers better results across most benchmark functions.To validate its real-world applicability,BaOA is tested on four engineering design problems,illustrating its capability to address practical challenges with remarkable efficiency.The results confirm BaOA’s versatility and reliability as an optimization tool.This study not only introduces an innovative algorithm but also establishes its effectiveness in solving complex problems,providing a foundation for future research and applications in diverse scientific and engineering domains.展开更多
Constant-step stress accelerated life test of Vacuum Fluorescent Display (VFD) was conducted with increased cathode temperature. Statistical analysis was done by applying Weibull distribution for describing the life, ...Constant-step stress accelerated life test of Vacuum Fluorescent Display (VFD) was conducted with increased cathode temperature. Statistical analysis was done by applying Weibull distribution for describing the life, and Least Square Method (LSM)for estimating Weibull parameters. Self-designed special software was used to predict the VFD life. Numerical results showed that the average life of VFD is over 30000 h, that the VFD life follows Weibull distribution, and that the life-stress relationship satisfies linear Arrhenius equation completely. Accurate calculation of the key parameter enabled rapid estimation of VFD life.展开更多
In this article,we review recent advances in the technology of writing fiber Bragg gratings(FBGs)in selected cores of multicore fibers(MCFs)by using femtosecond laser pulses.The writing technology of such a key elemen...In this article,we review recent advances in the technology of writing fiber Bragg gratings(FBGs)in selected cores of multicore fibers(MCFs)by using femtosecond laser pulses.The writing technology of such a key element as the FBG opens up wide opportunities for the creation of next generation fiber lasers and sensors based on MCFs.The advantages of the technology are shown by using the examples of 3D shape sensors,acoustic emission sensors with spatially multiplexed channels,as well as multicore fiber Raman lasers.展开更多
The present study focuses on the relationship of hardness with grain size for commercially pure titanium （CpTi） and ultra fine grained titanium （UFG-Ti） produced by equal channel angular process （ECAP） of Cp-Ti...The present study focuses on the relationship of hardness with grain size for commercially pure titanium （CpTi） and ultra fine grained titanium （UFG-Ti） produced by equal channel angular process （ECAP） of Cp-Ti）.Vickers and Knoop indentations of UFG-Ti at different loads was ～2.5 times harder than those of Cp-Ti.Xray diffraction （XRD） analysis showed peak broadening in UFG-Ti due to reduced grain size and micro-lattice strains.Scanning electron microscopy （SEM） revealed that ECAP had reduced the grain size of Cp-Ti by ～10 times.Weibull statistics showed UFG-Ti with lower dispersion in hardness values compare to Cp-Ti indicating a more uniform microstructure.展开更多
Under the hypotheses that the second-order and third-order derivatives of a function are bounded, an estimate of the radius of the convergence ball of Ostrowski-Traub＇s method is obtained. An error analysis is given ...Under the hypotheses that the second-order and third-order derivatives of a function are bounded, an estimate of the radius of the convergence ball of Ostrowski-Traub＇s method is obtained. An error analysis is given which matches the convergence order of the method. Finally, two examples are provided to show applications of our theorem.展开更多
The technique of organic exhaust gas decomposition with impulse corono dischrge plasma has been investigated in this study. It has been discovered that the impulse electric field affected the decomposition efficiency ...The technique of organic exhaust gas decomposition with impulse corono dischrge plasma has been investigated in this study. It has been discovered that the impulse electric field affected the decomposition efficiency with the secondary electron emission coefficient (δ) of the corona electrode as an intermediary: when the impulse voltage power ( W ) was fixed the corona electrode material with higher δ could induce higher decomposition efficiency. In these experiments, wolfram electrode which has the highest δ has really induced the highest decomposition efficiency.展开更多
This paper presents a novel carrier frequency offset estimation (CFO) algorithm for orthogonal frequency division multiplexing (OFDM)-based Wireless Local Area Networks (WLANs). Compared with previous approaches, this...This paper presents a novel carrier frequency offset estimation (CFO) algorithm for orthogonal frequency division multiplexing (OFDM)-based Wireless Local Area Networks (WLANs). Compared with previous approaches, this paper extends the whole frequency offset acquisition range by embedding a synthetic algorithm according to the preamble structure of WLANs symbols. The numerical results presented support the effectiveness of this algorithm by which the estimation error of the whole carrier frequency offset in the WLANs is effectively decreased.展开更多
PV modules are used as stand alone power sources for agricultural equipments such as lifting pumps in farms, where the power infrastructure is not yet improved. In order to expand the agricultural use of PV module, th...PV modules are used as stand alone power sources for agricultural equipments such as lifting pumps in farms, where the power infrastructure is not yet improved. In order to expand the agricultural use of PV module, the cost of PV generation should be reduced. In this paper, the power output performance of a commercial PV module was improved by using a sunlight concentrator that could be assembled inexpensively and a simple sun-tracking method.展开更多
We present an improved approach to determine the zero-dispersion wavelength by measurement of the four-wave mixing （FWM） effect employing the two-tunable-laser scanning method. The FWM behaviour of combined fibres w...We present an improved approach to determine the zero-dispersion wavelength by measurement of the four-wave mixing （FWM） effect employing the two-tunable-laser scanning method. The FWM behaviour of combined fibres with two different zero-dispersion wavelengths is investigated theoretically and experimentally. The results are compared with those by regular zero-dispersion wavelength test instrument using phase shift technique. The theoretical and experimental results confirm the feasibility of determination of zero-dispersion wavelength by FWM.展开更多
Considering cross-phase modulation,fiber loss and pulse walk off,the author studied analytically the evolutwn of the Stokes wave pumped by elementary soliton propagating in optical fiber.Cross-phase modulation leads t...Considering cross-phase modulation,fiber loss and pulse walk off,the author studied analytically the evolutwn of the Stokes wave pumped by elementary soliton propagating in optical fiber.Cross-phase modulation leads to the periodical amplification of the Stokes wave.There exists a maximum amplification distance due to soliton fiber loss.展开更多
The advantage of fuzzy controllers in working with inaccurate and nonlinear inputs is that there is no need for an accurate mathematical model and fast convergence and minimal fluctuations in the maximum power point d...The advantage of fuzzy controllers in working with inaccurate and nonlinear inputs is that there is no need for an accurate mathematical model and fast convergence and minimal fluctuations in the maximum power point detector.The capability of online fuzzy tracking systems is maximum power,resistance to radiation and temperature changes,and no need for external sensors to measure radiation intensity and temperature.However,the most important issue is the constant changes in the amount of sunlight that cause the maximum power point to be constantly changing.The controller used in the maximum power point tracking(MPPT)circuit must be able to adapt to the new radiation conditions.Therefore,in this paper,to more accurately track the maximumpower point of the solar system and receive more electrical power at its output,an adaptive fuzzy control was proposed,the parameters of which are optimized by the whale algorithm.The studies have repeated under different irradiation conditions and the proposed controller performance has been compared with perturb and observe algorithm(P&O)method,which is a practical and high-performance method.To evaluate the performance of the proposed algorithm,the particle swarm algorithm optimized the adaptive fuzzy controller.The simulation results show that the adaptive fuzzy control system performs better than the P&O tracking system.Higher accuracy and consequently more production power at the output of the solar panel is one of the salient features of the proposed control method,which distinguishes it from other methods.On the other hand,the adaptive fuzzy controller optimized by the whale algorithm has been able to perform relatively better than the controller designed by the particle swarm algorithm,which confirms the higher accuracy of the proposed algorithm.展开更多
The present work focuses mainly on an in vivo evaluation of ultra fine grained titanium （UFG-Ti） obtained by severe plastic deformation （SPD）. The SPD on commercially produced Grade 2 titanium （Cp-Ti） resulted i...The present work focuses mainly on an in vivo evaluation of ultra fine grained titanium （UFG-Ti） obtained by severe plastic deformation （SPD）. The SPD on commercially produced Grade 2 titanium （Cp-Ti） resulted in the refinement of the grain size by several orders of magnitude. Polished surfaces having similar roughness from both UFG-Ti and Cp-Ti were prepared. In vitro test revealed the presence of fibronectin, which was involved in the attachment of the cells to the substrate. Phase contrast micrographs showed the highest signal of fibronectin in UFG-Ti, indicating that it is more cytocompatible than Cp-Ti. In vivo tests, by subcutaneous implantation of the metals in the rats showed the better biocompatibility of UFG-Ti over Cp-Ti. The improved biocompatibility of UFG-Ti was attributed to the presence of surface discontinuities （in the form of nano-defects）, surface energy, higher wettability, surface stress and stable TiO2 films, which increased the protein adsorption on the surface.展开更多
In this paper,a K-line location algorithm for building block cells in LSI/VLSI ispresented.When the relative positions of rectangular cells are given,there are 2 states accordingto the two orientations of a cell.It is...In this paper,a K-line location algorithm for building block cells in LSI/VLSI ispresented.When the relative positions of rectangular cells are given,there are 2 states accordingto the two orientations of a cell.It is proved that to find the optimum solution from the 2~N statescan be reduced to calculate the N states in K-line algorithm.So the algorithm is shown veryeffective and can be used with association for cluster method in BBL placement.Under certainconditions,this method can also be used to pesudo BBL placement directly.展开更多
The present study suggests that series voltage injection is more effective than parallel current injection to improve voltage quality on the load side.The line voltage can be accurately symmetrized at the connection p...The present study suggests that series voltage injection is more effective than parallel current injection to improve voltage quality on the load side.The line voltage can be accurately symmetrized at the connection point by creating and controlling a series voltage component in each phase.This is more reliable and effective than parallel current injection.A dynamic voltage restorer(DVR)and a distribution static synchronous compensator(DSTATCOM)were utilized to provide the required power.The DVR is an effective andmodern device utilized in parallel within the grid and can protect sensitive loads from voltage problems in the grid by injecting voltage.The DVR and D-STATCOM were used to improve voltage stability in faults.A standard 13-bus system was studied in the presence of a wind farm.The simulation results demonstrated that single and three-phase overloads dramatically altered the voltage of the system,making it necessary to use compensators to improve voltage stability.The DVR and D-STATCOM showed similar performance under normal conditions and somewhat improved grid voltage unbalance.However,the DVR outperformed D-STATCOM under asymmetric faults conditions and led to lower voltage variations.展开更多
Analytical techniques and Liapunov method were used for the estimation of the attraction domain of memory patterns and local exponential stability of neural networks. The results were used to design efficient continuo...Analytical techniques and Liapunov method were used for the estimation of the attraction domain of memory patterns and local exponential stability of neural networks. The results were used to design efficient continuous feedback associative memory neural networks. The neural network synthesis procedure ensured the gain of large exponential convergence rate without reduction of the attraction domain.展开更多
The realization of security wired network is very critical when the network itself must be installed in an environment full of restrictions and constrains such as historical palaces, characterized by unique architectu...The realization of security wired network is very critical when the network itself must be installed in an environment full of restrictions and constrains such as historical palaces, characterized by unique architectural features. The purpose of this paper is to illustrate an advanced installation design technique of security wired network based on genetic algorithm optimisation that is capable of ensuring high performances of the network itself and significant reduction of the costs. The same technique can be extended to safety system such as fire signalling.展开更多
Wave reflection and refraction at the interface between a normal media and a one-dimensional left-handed material （1 DLHM） with a hyperbolic dispersion relationship is studied. It is found that in a special case tha...Wave reflection and refraction at the interface between a normal media and a one-dimensional left-handed material （1 DLHM） with a hyperbolic dispersion relationship is studied. It is found that in a special case that the boundary is perpendicular to one asymptotic line of the hyperbola, phase matching cannot be achieved unless the 1 DLHM is regarded to be intrinsically lossy. After introducing a small loss factor to the 1 DLHM, a reasonable solution for the phase matching is obtained. According to the analytical result, a wave confined to a thin layer near the boundary is found, which can be excited at the interface as a reflected wave or a refracted wave attenuating drastically away from the boundary inside the 1 DLHM in both cases.Wave reflection and refraction at the interface between a normal media and a one-dimensional left-handed material （1 DLHM） with a hyperbolic dispersion relationship is studied. It is found that in a special case that the boundary is perpendicular to one asymptotic fine of the hyperbola, phase matching cannot be achieved unless the 1 DLHM is regarded to be intrinsically lossy. After introducing a small loss factor to the 1 DLHM, a reasonable solution for the phase matching is obtained. According to the analytical result, a wave confined to a thin layer near the boundary is found, which can be excited at the interface as a reflected wave or a refracted wave attenuating drastically away from the boundary inside the 1 DLHM in both cases.展开更多
Considering the phenomenon of Latch-up in CMOS device,some patterns of manifestation about Latch-up in electronic system are analyzed with three actual circuits,meanwhile the correlative solving methods are also provi...Considering the phenomenon of Latch-up in CMOS device,some patterns of manifestation about Latch-up in electronic system are analyzed with three actual circuits,meanwhile the correlative solving methods are also provided. To avoid Latch-up,some general principles are proposed. The analyzing and solving processes derived from practical system design are verified simple and ef-fective in large number of products,and to some extend have general reference value in anti-latch-up design of application systems.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 61972424 and 62372479in part by the High Value Intellectual Property Cultivation Project of Hubei Province,China,under grant D2021002094+1 种基金in part by JSPS KAKENHI under Grants JP16K00117 and JP19K20250in part by the Leading Initiative for Excellent Young Researchers(LEADER),MEXT,Japan,and KDDI Foundation.
文摘Named data networking(NDNs)is an idealized deployment of information-centric networking(ICN)that has attracted attention from scientists and scholars worldwide.A distributed in-network caching scheme can efficiently realize load balancing.However,such a ubiquitous caching approach may cause problems including duplicate caching and low data diversity,thus reducing the caching efficiency of NDN routers.To mitigate these caching problems and improve the NDN caching efficiency,in this paper,a hierarchical-based sequential caching(HSC)scheme is proposed.In this scheme,the NDN routers in the data transmission path are divided into various levels and data with different request frequencies are cached in distinct router levels.The aim is to cache data with high request frequencies in the router that is closest to the content requester to increase the response probability of the nearby data,improve the data caching efficiency of named data networks,shorten the response time,and reduce cache redundancy.Simulation results show that this scheme can effectively improve the cache hit rate(CHR)and reduce the average request delay(ARD)and average route hop(ARH).
文摘In this study,a completely different approach to optimization is introduced through the development of a novel metaheuristic algorithm called the Barber Optimization Algorithm(BaOA).Inspired by the human interactions between barbers and customers,BaOA captures two key processes:the customer’s selection of a hairstyle and the detailed refinement during the haircut.These processes are translated into a mathematical framework that forms the foundation of BaOA,consisting of two critical phases:exploration,representing the creative selection process,and exploitation,which focuses on refining details for optimization.The performance of BaOA is evaluated using 52 standard benchmark functions,including unimodal,high-dimensional multimodal,fixed-dimensional multimodal,and the Congress on Evolutionary Computation(CEC)2017 test suite.This comprehensive assessment highlights BaOA’s ability to balance exploration and exploitation effectively,resulting in high-quality solutions.A comparative analysis against twelve widely known metaheuristic algorithms further demonstrates BaOA’s superior performance,as it consistently delivers better results across most benchmark functions.To validate its real-world applicability,BaOA is tested on four engineering design problems,illustrating its capability to address practical challenges with remarkable efficiency.The results confirm BaOA’s versatility and reliability as an optimization tool.This study not only introduces an innovative algorithm but also establishes its effectiveness in solving complex problems,providing a foundation for future research and applications in diverse scientific and engineering domains.
基金Project supported by the Postdoctoral Scientific Research Foundation of Zhejiang Province of China, and the Special Fund of Cooperation between Shaoxing City and Zhejiang University of China
文摘Constant-step stress accelerated life test of Vacuum Fluorescent Display (VFD) was conducted with increased cathode temperature. Statistical analysis was done by applying Weibull distribution for describing the life, and Least Square Method (LSM)for estimating Weibull parameters. Self-designed special software was used to predict the VFD life. Numerical results showed that the average life of VFD is over 30000 h, that the VFD life follows Weibull distribution, and that the life-stress relationship satisfies linear Arrhenius equation completely. Accurate calculation of the key parameter enabled rapid estimation of VFD life.
基金supported by the Russian Ministry of Science and Higher Education (14.Y26.31.0017)Russian Foundation for Basic Research(18-52-7822)the work concerning MCF fiber Raman lasers was supported by Russian Science Foundation (21-72-30024)
文摘In this article,we review recent advances in the technology of writing fiber Bragg gratings(FBGs)in selected cores of multicore fibers(MCFs)by using femtosecond laser pulses.The writing technology of such a key element as the FBG opens up wide opportunities for the creation of next generation fiber lasers and sensors based on MCFs.The advantages of the technology are shown by using the examples of 3D shape sensors,acoustic emission sensors with spatially multiplexed channels,as well as multicore fiber Raman lasers.
文摘The present study focuses on the relationship of hardness with grain size for commercially pure titanium （CpTi） and ultra fine grained titanium （UFG-Ti） produced by equal channel angular process （ECAP） of Cp-Ti）.Vickers and Knoop indentations of UFG-Ti at different loads was ～2.5 times harder than those of Cp-Ti.Xray diffraction （XRD） analysis showed peak broadening in UFG-Ti due to reduced grain size and micro-lattice strains.Scanning electron microscopy （SEM） revealed that ECAP had reduced the grain size of Cp-Ti by ～10 times.Weibull statistics showed UFG-Ti with lower dispersion in hardness values compare to Cp-Ti indicating a more uniform microstructure.
基金Supported by the National Natural Science Foundation of China (10871178)the Natural Science Foundation(Y606154)the Foundation of the Eduction Department of Zhejiang Province of China (Y200804008)
文摘Under the hypotheses that the second-order and third-order derivatives of a function are bounded, an estimate of the radius of the convergence ball of Ostrowski-Traub＇s method is obtained. An error analysis is given which matches the convergence order of the method. Finally, two examples are provided to show applications of our theorem.
文摘The technique of organic exhaust gas decomposition with impulse corono dischrge plasma has been investigated in this study. It has been discovered that the impulse electric field affected the decomposition efficiency with the secondary electron emission coefficient (δ) of the corona electrode as an intermediary: when the impulse voltage power ( W ) was fixed the corona electrode material with higher δ could induce higher decomposition efficiency. In these experiments, wolfram electrode which has the highest δ has really induced the highest decomposition efficiency.
基金Project supported by the National Natural Science Foundation of China (No. 2004012F33AA), and Education Foundation of Zhe- jiang Education Department (No. 20040125-66), China
文摘This paper presents a novel carrier frequency offset estimation (CFO) algorithm for orthogonal frequency division multiplexing (OFDM)-based Wireless Local Area Networks (WLANs). Compared with previous approaches, this paper extends the whole frequency offset acquisition range by embedding a synthetic algorithm according to the preamble structure of WLANs symbols. The numerical results presented support the effectiveness of this algorithm by which the estimation error of the whole carrier frequency offset in the WLANs is effectively decreased.
基金Supported by Curriculum for Practical Overseas Education in La Paz, Mexico
文摘PV modules are used as stand alone power sources for agricultural equipments such as lifting pumps in farms, where the power infrastructure is not yet improved. In order to expand the agricultural use of PV module, the cost of PV generation should be reduced. In this paper, the power output performance of a commercial PV module was improved by using a sunlight concentrator that could be assembled inexpensively and a simple sun-tracking method.
文摘We present an improved approach to determine the zero-dispersion wavelength by measurement of the four-wave mixing （FWM） effect employing the two-tunable-laser scanning method. The FWM behaviour of combined fibres with two different zero-dispersion wavelengths is investigated theoretically and experimentally. The results are compared with those by regular zero-dispersion wavelength test instrument using phase shift technique. The theoretical and experimental results confirm the feasibility of determination of zero-dispersion wavelength by FWM.
文摘Considering cross-phase modulation,fiber loss and pulse walk off,the author studied analytically the evolutwn of the Stokes wave pumped by elementary soliton propagating in optical fiber.Cross-phase modulation leads to the periodical amplification of the Stokes wave.There exists a maximum amplification distance due to soliton fiber loss.
文摘The advantage of fuzzy controllers in working with inaccurate and nonlinear inputs is that there is no need for an accurate mathematical model and fast convergence and minimal fluctuations in the maximum power point detector.The capability of online fuzzy tracking systems is maximum power,resistance to radiation and temperature changes,and no need for external sensors to measure radiation intensity and temperature.However,the most important issue is the constant changes in the amount of sunlight that cause the maximum power point to be constantly changing.The controller used in the maximum power point tracking(MPPT)circuit must be able to adapt to the new radiation conditions.Therefore,in this paper,to more accurately track the maximumpower point of the solar system and receive more electrical power at its output,an adaptive fuzzy control was proposed,the parameters of which are optimized by the whale algorithm.The studies have repeated under different irradiation conditions and the proposed controller performance has been compared with perturb and observe algorithm(P&O)method,which is a practical and high-performance method.To evaluate the performance of the proposed algorithm,the particle swarm algorithm optimized the adaptive fuzzy controller.The simulation results show that the adaptive fuzzy control system performs better than the P&O tracking system.Higher accuracy and consequently more production power at the output of the solar panel is one of the salient features of the proposed control method,which distinguishes it from other methods.On the other hand,the adaptive fuzzy controller optimized by the whale algorithm has been able to perform relatively better than the controller designed by the particle swarm algorithm,which confirms the higher accuracy of the proposed algorithm.
文摘The present work focuses mainly on an in vivo evaluation of ultra fine grained titanium （UFG-Ti） obtained by severe plastic deformation （SPD）. The SPD on commercially produced Grade 2 titanium （Cp-Ti） resulted in the refinement of the grain size by several orders of magnitude. Polished surfaces having similar roughness from both UFG-Ti and Cp-Ti were prepared. In vitro test revealed the presence of fibronectin, which was involved in the attachment of the cells to the substrate. Phase contrast micrographs showed the highest signal of fibronectin in UFG-Ti, indicating that it is more cytocompatible than Cp-Ti. In vivo tests, by subcutaneous implantation of the metals in the rats showed the better biocompatibility of UFG-Ti over Cp-Ti. The improved biocompatibility of UFG-Ti was attributed to the presence of surface discontinuities （in the form of nano-defects）, surface energy, higher wettability, surface stress and stable TiO2 films, which increased the protein adsorption on the surface.
文摘In this paper,a K-line location algorithm for building block cells in LSI/VLSI ispresented.When the relative positions of rectangular cells are given,there are 2 states accordingto the two orientations of a cell.It is proved that to find the optimum solution from the 2~N statescan be reduced to calculate the N states in K-line algorithm.So the algorithm is shown veryeffective and can be used with association for cluster method in BBL placement.Under certainconditions,this method can also be used to pesudo BBL placement directly.
基金International Research Partnership“Electrical Engineering-Thai French Research Center(EE-TFRC)”under the project framework of the Lorraine Universitéd’Excellence(LUE)in cooperation between Universitéde Lorraine and King Mongkut’s University of Technology North Bangkok and in part by the National Research Council of Thailand(NRCT)under Senior Research Scholar Program under Grant No.N42A640328National Science,Research and Innovation Fund(NSRF)under King Mongkut’s University of Technology North Bangkok under Grant No.KMUTNB-FF-65-20.
文摘The present study suggests that series voltage injection is more effective than parallel current injection to improve voltage quality on the load side.The line voltage can be accurately symmetrized at the connection point by creating and controlling a series voltage component in each phase.This is more reliable and effective than parallel current injection.A dynamic voltage restorer(DVR)and a distribution static synchronous compensator(DSTATCOM)were utilized to provide the required power.The DVR is an effective andmodern device utilized in parallel within the grid and can protect sensitive loads from voltage problems in the grid by injecting voltage.The DVR and D-STATCOM were used to improve voltage stability in faults.A standard 13-bus system was studied in the presence of a wind farm.The simulation results demonstrated that single and three-phase overloads dramatically altered the voltage of the system,making it necessary to use compensators to improve voltage stability.The DVR and D-STATCOM showed similar performance under normal conditions and somewhat improved grid voltage unbalance.However,the DVR outperformed D-STATCOM under asymmetric faults conditions and led to lower voltage variations.
文摘Analytical techniques and Liapunov method were used for the estimation of the attraction domain of memory patterns and local exponential stability of neural networks. The results were used to design efficient continuous feedback associative memory neural networks. The neural network synthesis procedure ensured the gain of large exponential convergence rate without reduction of the attraction domain.
文摘The realization of security wired network is very critical when the network itself must be installed in an environment full of restrictions and constrains such as historical palaces, characterized by unique architectural features. The purpose of this paper is to illustrate an advanced installation design technique of security wired network based on genetic algorithm optimisation that is capable of ensuring high performances of the network itself and significant reduction of the costs. The same technique can be extended to safety system such as fire signalling.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60531020, 60201001, 60277018 and 60371010.
文摘Wave reflection and refraction at the interface between a normal media and a one-dimensional left-handed material （1 DLHM） with a hyperbolic dispersion relationship is studied. It is found that in a special case that the boundary is perpendicular to one asymptotic line of the hyperbola, phase matching cannot be achieved unless the 1 DLHM is regarded to be intrinsically lossy. After introducing a small loss factor to the 1 DLHM, a reasonable solution for the phase matching is obtained. According to the analytical result, a wave confined to a thin layer near the boundary is found, which can be excited at the interface as a reflected wave or a refracted wave attenuating drastically away from the boundary inside the 1 DLHM in both cases.Wave reflection and refraction at the interface between a normal media and a one-dimensional left-handed material （1 DLHM） with a hyperbolic dispersion relationship is studied. It is found that in a special case that the boundary is perpendicular to one asymptotic fine of the hyperbola, phase matching cannot be achieved unless the 1 DLHM is regarded to be intrinsically lossy. After introducing a small loss factor to the 1 DLHM, a reasonable solution for the phase matching is obtained. According to the analytical result, a wave confined to a thin layer near the boundary is found, which can be excited at the interface as a reflected wave or a refracted wave attenuating drastically away from the boundary inside the 1 DLHM in both cases.
基金A Project Supported by Scientific Research Fund of Zhejiang Provincial Education Department. Project name:Research and Design on Network Communication Controller for Fiber Cable TV.Project number:20061473.
文摘Considering the phenomenon of Latch-up in CMOS device,some patterns of manifestation about Latch-up in electronic system are analyzed with three actual circuits,meanwhile the correlative solving methods are also provided. To avoid Latch-up,some general principles are proposed. The analyzing and solving processes derived from practical system design are verified simple and ef-fective in large number of products,and to some extend have general reference value in anti-latch-up design of application systems.
