期刊文献+
共找到86篇文章
< 1 2 5 >
每页显示 20 50 100
The Dual of the Two-Variable Exponent Amalgam Spaces (Lq(),lp())(Ω)
1
作者 Sambourou Massinanke Sékou Coulibaly Mamadou Traore 《Journal of Applied Mathematics and Physics》 2024年第2期383-431,共49页
Wiener amalgam spaces are a class of function spaces where the function’s local and global behavior can be easily distinguished. These spaces are ex-tensively used in Harmonic analysis that originated in the work of ... Wiener amalgam spaces are a class of function spaces where the function’s local and global behavior can be easily distinguished. These spaces are ex-tensively used in Harmonic analysis that originated in the work of Wiener. In this paper: we first introduce a two-variable exponent amalgam space (L<sup>q</sup><sup>()</sup>,l<sup>p</sup><sup>()</sup>)(Ω). Secondly, we investigate some basic properties of these spaces, and finally, we study their dual. 展开更多
关键词 Amalgam spaces Variable Exponent Lebesgue spaces Dual of a Vector space
下载PDF
Indirect Vector Control of Linear Induction Motors Using Space Vector Pulse Width Modulation 被引量:1
2
作者 Arjmand Khaliq Syed Abdul Rahman Kashif +5 位作者 Fahad Ahmad Muhammad Anwar Qaisar Shaheen Rizwan Akhtar Muhammad Arif Shah Abdelzahir Abdelmaboud 《Computers, Materials & Continua》 SCIE EI 2023年第3期6263-6287,共25页
Vector control schemes have recently been used to drive linear induction motors(LIM)in high-performance applications.This trend promotes the development of precise and efficient control schemes for individual motors.T... Vector control schemes have recently been used to drive linear induction motors(LIM)in high-performance applications.This trend promotes the development of precise and efficient control schemes for individual motors.This research aims to present a novel framework for speed and thrust force control of LIM using space vector pulse width modulation(SVPWM)inverters.The framework under consideration is developed in four stages.To begin,MATLAB Simulink was used to develop a detailed mathematical and electromechanical dynamicmodel.The research presents a modified SVPWM inverter control scheme.By tuning the proportional-integral(PI)controller with a transfer function,optimized values for the PI controller are derived.All the subsystems mentioned above are integrated to create a robust simulation of the LIM’s precise speed and thrust force control scheme.The reference speed values were chosen to evaluate the performance of the respective system,and the developed system’s response was verified using various data sets.For the low-speed range,a reference value of 10m/s is used,while a reference value of 100 m/s is used for the high-speed range.The speed output response indicates that themotor reached reference speed in amatter of seconds,as the delay time is between 8 and 10 s.The maximum amplitude of thrust achieved is less than 400N,demonstrating the controller’s capability to control a high-speed LIM with minimal thrust ripple.Due to the controlled speed range,the developed system is highly recommended for low-speed and high-speed and heavy-duty traction applications. 展开更多
关键词 space vector pulse width modulation linear induction motor proportional-integral controller indirect vector control electromechanical dynamic modeling
下载PDF
Near-Vector Spaces Constructed over Zp, for p a Prime
3
作者 Kelone Tefoetsile Jeromy Kalunga +3 位作者 Mathews Zimba James Muchinga Saviour Chibeti Henry M. Phiri 《Advances in Pure Mathematics》 2023年第1期11-33,共23页
The purpose of this paper is to construct near-vector spaces using a result by Van der Walt, with Z<sub>p</sub> for p a prime, as the underlying near-field. There are two notions of near-vector spaces, we ... The purpose of this paper is to construct near-vector spaces using a result by Van der Walt, with Z<sub>p</sub> for p a prime, as the underlying near-field. There are two notions of near-vector spaces, we focus on those studied by André [1]. These near-vector spaces have recently proven to be very useful in finite linear games. We will discuss the construction and properties, give examples of these near-vector spaces and give its application in finite linear games. 展开更多
关键词 Vector spaces Near Vector spaces REGULARITY Compatibility Fields Near-Fields F-Group and Quasi-Kernel
下载PDF
Word Embeddings and Semantic Spaces in Natural Language Processing
4
作者 Peter J. Worth 《International Journal of Intelligence Science》 2023年第1期1-21,共21页
One of the critical hurdles, and breakthroughs, in the field of Natural Language Processing (NLP) in the last two decades has been the development of techniques for text representation that solves the so-called curse ... One of the critical hurdles, and breakthroughs, in the field of Natural Language Processing (NLP) in the last two decades has been the development of techniques for text representation that solves the so-called curse of dimensionality, a problem which plagues NLP in general given that the feature set for learning starts as a function of the size of the language in question, upwards of hundreds of thousands of terms typically. As such, much of the research and development in NLP in the last two decades has been in finding and optimizing solutions to this problem, to feature selection in NLP effectively. This paper looks at the development of these various techniques, leveraging a variety of statistical methods which rest on linguistic theories that were advanced in the middle of the last century, namely the distributional hypothesis which suggests that words that are found in similar contexts generally have similar meanings. In this survey paper we look at the development of some of the most popular of these techniques from a mathematical as well as data structure perspective, from Latent Semantic Analysis to Vector Space Models to their more modern variants which are typically referred to as word embeddings. In this review of algoriths such as Word2Vec, GloVe, ELMo and BERT, we explore the idea of semantic spaces more generally beyond applicability to NLP. 展开更多
关键词 Natural Language Processing Vector space Models Semantic spaces Word Embeddings Representation Learning Text Vectorization Machine Learning Deep Learning
下载PDF
EMBEDDING THEOREMS ON CAMPANATO-MORREY SPACES FOR VECTOR FIELDS OF HoRMANDER TYPE 被引量:3
5
作者 Guozhen Lu (Wright State University, USA) 《Analysis in Theory and Applications》 1998年第1期69-80,共12页
This paper deals with embedding theorems on Campanato-Marrey spaces formed by degenerate vector fields, which include Honnander and Grushin type of vector fields. These embedding theorems are somewhat different from t... This paper deals with embedding theorems on Campanato-Marrey spaces formed by degenerate vector fields, which include Honnander and Grushin type of vector fields. These embedding theorems are somewhat different from the known Poincare estimates. The main ingredients of the proofs rely on the fractional maximal functions. These results evidently have applications to the regularity of subelliptic PDE. 展开更多
关键词 EMBEDDING THEOREMS ON CAMPANATO-MORREY spaceS FOR VECTOR FIELDS OF HoRMANDER TYPE MATH
下载PDF
Dynamic Vector Space Secret Sharing Based on Certificates 被引量:1
6
作者 XU Chunxiang LI Jiajia LIU Dongsu 《Wuhan University Journal of Natural Sciences》 CAS 2006年第5期1253-1256,共4页
A vector space secret sharing scheme based on certificates is proposed in this paper. The difficulties of solving discrete logarithm assure confidential information's security, and the use of each participant's cert... A vector space secret sharing scheme based on certificates is proposed in this paper. The difficulties of solving discrete logarithm assure confidential information's security, and the use of each participant's certificate makes the dealer have no need to transfer secret information to the participants. The proposed scheme is dynamic. It can effectively check cheaters and does not have secure channel requirements. 展开更多
关键词 vector space secret sharing dynamic secret sharing CERTIFICATE
下载PDF
Composition Operators with Linear Fractional Symbols on Vector-Valued Bergman Spaces 被引量:1
7
作者 WangMao-fa UuPei-de ZhouShao-bo 《Wuhan University Journal of Natural Sciences》 CAS 2003年第03A期759-764,共6页
Let φ and ψ be linear fractional self\|maps of the unit disk D and X a separable Hilbert space. In this paper we completely characterize the weak compactness of the product operators of a composition operation C φ... Let φ and ψ be linear fractional self\|maps of the unit disk D and X a separable Hilbert space. In this paper we completely characterize the weak compactness of the product operators of a composition operation C φ with another one's adjoint C * ψ on the vector\|valued Bergman space B 1(X) for forms C φC * ψ and C * ψC φ. 展开更多
关键词 vector\|valued Bergman space composition operator linear fractional map angular derivative weak compactness
下载PDF
A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM 被引量:1
8
《变频器世界》 2006年第12期26-27,共2页
Ⅰ. INTRODUCTION MULTILEVEL inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters, such as lower common-mode voltage, lower d... Ⅰ. INTRODUCTION MULTILEVEL inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters, such as lower common-mode voltage, lower dv/dt, lower harmonics in output voltage and current, and reduced voltage on the power switches. 展开更多
关键词 A space Vector PWM Scheme for Multilevel Inverters Based on Two-Level space Vector PWM In
下载PDF
Realization of Space Vector Pulse Width Modulation Method Based on DSP
9
作者 HAN Rukun ZHAO Yulin 《Journal of Northeast Agricultural University(English Edition)》 CAS 2008年第3期56-59,共4页
In order to compensate for the deficiency of Sine Pulse Width Modulation(SPWM), on the base of analyzing the principle of space w tot pulse width modulation and being compared with SPWM, the method of solving workin... In order to compensate for the deficiency of Sine Pulse Width Modulation(SPWM), on the base of analyzing the principle of space w tot pulse width modulation and being compared with SPWM, the method of solving working time of adjacent vector and the method of generate space voltage vector were introduced. The experiment to the inverter which consists of IGBT proves that SVPWM centrol algorithm can reduce harmonic effectively, it is beneficial to enhancing the utilization rate of voltage source inverter direct current power supply. 展开更多
关键词 space vector pulse width modulation DSP space vector
下载PDF
ON THE SYMPLECTIC INVARIANTS OF A SUBSPACE OF A VECTOR SPACE~*
10
作者 万哲先 《Acta Mathematica Scientia》 SCIE CSCD 1991年第3期251-253,共3页
Let F be any commutative field. Let v be an integer≥1 and be a fixed 2v × 2v nonsingular alternate matrix over F. Define Sp(F)={T: 2v×2v matrix over F|TKT~T=K}. It is well-known that Sp(F) is a group with r... Let F be any commutative field. Let v be an integer≥1 and be a fixed 2v × 2v nonsingular alternate matrix over F. Define Sp(F)={T: 2v×2v matrix over F|TKT~T=K}. It is well-known that Sp(F) is a group with respect to the matrix multiplication and is called the symplectic group of degree 2v over F 展开更多
关键词 OVER PR ON THE SYMPLECTIC INVARIANTS OF A SUBspace OF A VECTOR space
下载PDF
COVERING PROPERTIES ON H-SPACES AND APPLICATIONS
11
作者 丁协平 陈国强 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1993年第12期1079-1088,共10页
Several theorems on closed (resp. open) covering properties of H-spaces are obtained which improve and generalize the corresponding results of Sperner, Klee, Alexandroff-Pasynkoff, Berge, Ghouila-Houri, Danzer-Grunbau... Several theorems on closed (resp. open) covering properties of H-spaces are obtained which improve and generalize the corresponding results of Sperner, Klee, Alexandroff-Pasynkoff, Berge, Ghouila-Houri, Danzer-Grunbaum-Klee, Ky Fan, Shih-Tan, Horvath and Lassonde. As application an almost fixed point theorem for lower semi-continuous map in l.c.-spaces and a generalization of Tychonoffs fixed point theorem are proved in l.c.-spaces which improve those results of Ky Fan and Horvath. 展开更多
关键词 covering property H-space H-convex H-convex hull almost fixed point lower semi-continuous l.c.-space SIMPLEX uniform structure topological vector space locally convex space contractible
下载PDF
MAXIMAL ELEMENTS OF CONDENSING PREFERENCE MAPS IN LOCALLY CONVEX HAUSDORFF SPACES
12
作者 丁协平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1991年第8期741-744,共4页
Two existence theorems of maximal elements of condensing preference maps in locally convex Hausdorff spaces are proved which generalize the recent results of Mehta. One of them positively answers the open problem ment... Two existence theorems of maximal elements of condensing preference maps in locally convex Hausdorff spaces are proved which generalize the recent results of Mehta. One of them positively answers the open problem mentioned by Mehta. 展开更多
关键词 topological vector space condensing preference map maximal element
下载PDF
Harmonic Domain Modelling of Space Vector Based STATCOM
13
作者 Devendra Manikrao Holey Vinod Kumar Chandrakar 《Energy and Power Engineering》 2016年第4期195-203,共9页
This paper presents frequency domain method for harmonic analysis of space vector based STATCOM. Space Vector Pulse Width Modulation (SVPWM) method is an advanced PWM method. It is a best method among all the PWM tech... This paper presents frequency domain method for harmonic analysis of space vector based STATCOM. Space Vector Pulse Width Modulation (SVPWM) method is an advanced PWM method. It is a best method among all the PWM techniques. It provides a freedom in a switching cycle for placement space vector. In this paper, the SVPWM is used for switching of STATCOM. The harmonic (or frequency) domain is a steady-state form of harmonic analysis method, which represents converters to their harmonic spectra. This paper presents harmonic analysis by means of harmonic domain for space vector based Static shunt converter (STATCOM). Performance of the STATCOM is evaluated in harmonic domain simulation studies in MATLAB environment. 展开更多
关键词 Harmonic Domain Voltage Source Converter (VSC) space Vector Modulation (SVM) Static Shunt Compensator (STATCOM)
下载PDF
Dynamic Harmonic Domain Modelling of Space Vector Based SSSC
14
作者 Devendra M. Holey Vinod Kumar Chandrakar 《Energy and Power Engineering》 2016年第3期152-160,共9页
This paper presents analytical frequency domain method for harmonic modeling and evaluation of Space Vector Pulse Width Modulation (SVPWM) based static synchronous series converter (SSSC). SVPWM is the best among all ... This paper presents analytical frequency domain method for harmonic modeling and evaluation of Space Vector Pulse Width Modulation (SVPWM) based static synchronous series converter (SSSC). SVPWM is the best among all the PWM techniques. It gives a degree of freedom of space vector placement in a switching cycle. Dynamic modeling technique is used for space vector modulation (SVM) based voltage source converter that is adapted as a static synchronous series converter (SSSC) for harmonic analysis using dynamic harmonic domain. Performance of the SSSC is evaluated in dynamic harmonic domain simulation studies in MATLAB environment. The switching function spectra are necessary for harmonic transfer matrix which is calculated using Fourier series. This paper presents the analysis of harmonics for space vector based SSSC during steady state and dynamic condition. 展开更多
关键词 Dynamics Harmonic Domain Voltage Source Converter (VSC) space Vector Modulation (SVM) Static Synchronus Series Compensator (SSSC)
下载PDF
ON THE DECOMPOSITION OF COMPLEX VECTOR SPACES AND THE JORDAN CANONICAL FORM OF COMPLEX LINEAR TRANSFORMATIONS
15
作者 肖衡 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第11期997-1003,共7页
New objects characterizing the structure of complex linear transformations areintroduced. These new objects yield a new result for the decomposition of complexvector spaces relative to complex lrnear transformations a... New objects characterizing the structure of complex linear transformations areintroduced. These new objects yield a new result for the decomposition of complexvector spaces relative to complex lrnear transformations and provide all Jordan basesby which the Jordan canonical form is constructed. Accordingly, they can result in thecelebrated Jordan theorem and the third decomposition theorem of space directly. and,moreover, they can give a new deep insight into the exquisite and subtle structure ofthe Jordan form. The latter indicates that the Jordan canonical form of a complexlinear transformation is an invariant structure associated with double arbitrary. choices. 展开更多
关键词 complex vector space complex linear transformation. decompo-sition theorems. Jordan canonical form
下载PDF
On Irresolute Topological Vector Spaces
16
作者 Moizud Din Khan Muhammad Asad Iqbal 《Advances in Pure Mathematics》 2016年第2期105-112,共8页
In this paper, our focus is to investigate the notion of irresolute topological vector spaces. Irresolute topological vector spaces are defined by using semi open sets and irresolute mappings. The notion of irresolute... In this paper, our focus is to investigate the notion of irresolute topological vector spaces. Irresolute topological vector spaces are defined by using semi open sets and irresolute mappings. The notion of irresolute topological vector spaces is analog to the notion of topological vector spaces, but mathematically it behaves differently. An example is given to show that an irresolute topological vector space is not a topological vector space. It is proved that: 1) Irresolute topological vector spaces possess open hereditary property;2) A homomorphism of irresolute topological vector spaces is irresolute if and only if it is irresolute at identity element;3) In irresolute topological vector spaces, the scalar multiple of semi compact set is semi compact;4) In irresolute topological vector spaces, every semi open set is translationally invariant. 展开更多
关键词 Topological Vector space Irresolute Topological Vector space Irresolue Mapping Semi Open Set
下载PDF
Construction of PBIB Desings by Using Subspace of Vector Space over Finite Fields
17
作者 Wei Wandi (Dept. of Math. Sichuan University, Chengdu 610014)Yang Benfu ( Dept.of Math. Chengdu Teachers College, Pengzhou 611930) 《西华大学学报(哲学社会科学版)》 1998年第3期1-4,共4页
A new transitivity theorem of the general linear group GLn(Fq)is proved. A kind of new PBIB desings is constructed.
关键词 OVER Construction of PBIB Desings by Using Subspace of Vector space over Finite Fields
下载PDF
ANFIS Based Space Vector Modulation-DTC for Switched Reluctance Motor Drive
18
作者 T. Srihari R. Jeyabaharath P. Veena 《Circuits and Systems》 2016年第10期2940-2947,共9页
Direct torque control (DTC) of Switched reluctance motor is known straightforward control structure with similar execution to that of field situated control strategies. In any case, the part of ideal determination of ... Direct torque control (DTC) of Switched reluctance motor is known straightforward control structure with similar execution to that of field situated control strategies. In any case, the part of ideal determination of the voltage space vector is one of the weakest focuses in a routine DTC drive because of adjustable switching frequency and high torque ripple. In this paper, ideal choice of voltage space vectors is accomplished utilizing ANFIS (Adaptive Neuro Fuzzy Inference System) with space vector Modulation. SVM-DTC gives consistent switching frequency and the proposed ANFIS controller’s structure manages the torque and stator flux error signals through the fuzzy deduction to get a yield that takes the type of space voltage vector. Simulation results accept the proposed evolutionary system with quick torque and flux reaction with minimized torque ripple and flux ripple. 展开更多
关键词 ANFIS Direct Torque Control Flux Control space Vector Modulation Switched Reluctance Motor
下载PDF
An Improved Hybrid Space Vector PWM Technique for IM Drives
19
作者 P. Muthukumar P. Melba Mary S. Jeevananthan 《Circuits and Systems》 2016年第9期2120-2131,共13页
In this paper, an improved hybrid space vector pulse width modulation (HSVPWM) technique is proposed for IM (induction motor) drives. The basic principle involved in the proposed random pulse width modulation (RPWM) c... In this paper, an improved hybrid space vector pulse width modulation (HSVPWM) technique is proposed for IM (induction motor) drives. The basic principle involved in the proposed random pulse width modulation (RPWM) cuddled SVPWM is amalgamating the pre-calculated switching timings for various sections of hexagonal space vector boundary and the random selection of carrier between two triangular signals, in order to disband acoustic switching noise spectrum with improved fundamental component. The arbitrary selection between triangular carriers, which is decided by digital signal states (Low or High) of the linear feedback shift register (LFSR) based pseudo random binary sequence (PRBS) generator. The SVPWM offers a control degree of freedom in terms of positioning of vectors inside every sampling interval and hence it has six possible variants of the voltage vectors arrangements in each sector. The developed HSVPWM is thoroughly analyzed in using the MATLAB? based simulation for all SVPWM variants. From the simulation and experimental results viz. harmonic spectrum, harmonic spread factor (HSF), total harmonic distortion (THD) etc., and the superiority of the proposed scheme such as better utilization of DC bus and the randomization of the harmonic power are evidenced. For the practical implementation, Xilinx XC3S500E FPGA device has been used. 展开更多
关键词 Harmonic Spread Factor Hybrid space Vector Pulse Width Modulation Pseudo Random Binary Sequence Random Pulse Width Modulation
下载PDF
THD Reduction for Permanent Magnet Synchronous Motor Using Simulated Annealing
20
作者 R.Senthil Rama C.R.Edwin Selva Rex +1 位作者 N.Herald Anantha Rufus J.Annrose 《Intelligent Automation & Soft Computing》 SCIE 2023年第2期2325-2336,共12页
Any nonlinear behavior of the system is analyzed by a useful way of Total Harmonic Distortion(THD)technique.Reduced THD achieves lower peak current,higher efficiency and longer equipment life span.Simulated annealing(S... Any nonlinear behavior of the system is analyzed by a useful way of Total Harmonic Distortion(THD)technique.Reduced THD achieves lower peak current,higher efficiency and longer equipment life span.Simulated annealing(SA)is applied due to the effectiveness of locating solutions that are close to ideal and to challenge large-scale combinatorial optimization for Permanent Magnet Synchronous Machine(PMSM).The parameters of direct torque controllers(DTC)for the drive are automatically adjusted by the optimization algorithm.Advantages of the PI-Fuzzy-SA algorithm are retained when used together.It also improves the rate of system convergence.Speed response improvement and har-monic reduction is achieved with SA-based DTC for PMSM.This mechanism is known to be faster than other algorithms.Also,it is observed that as compared to other algorithms,the projected algorithm yields a reduced total harmonic distor-tion.As a result of the employment of Space Vector Modulation(SVM)techni-que,the system is resistant to changes in motor specifications and load torque.Through MATLAB&Simulink simulation,the experiment is done and the per-formance is calculated for the controller. 展开更多
关键词 PMSM simulated annealing space vector modulation direct torque control THD
下载PDF
上一页 1 2 5 下一页 到第
使用帮助 返回顶部