Dynamic load balancing with learning model for Sudoku solving system

This paper proposes a dynamic load balancing with learning model for a Sudoku problem solving system that has multiple workers and multiple solvers. The objective is to minimise the total processing time of problem solving. Our load balancing with learning model distributes each Sudoku problem to an appropriate pair of worker and solver when it is received by the system. The information of the estimated solution time for a specific number of given input values, the estimated finishing time of each worker, and the idle status of each worker is used to determine the worker-solver pairs. In addition, the proposed system can estimate the waiting period for each problem. Test results show that the system has shorter processing time than conventional alternatives.     

基于FPGA的直序扩频系统的同步设计

针对直序扩频系统中伪随机码同步捕获的问题,提出了一种扩频码捕获方法,来解决低信噪比条件下伪码序列的捕获问题。首先对直接序列扩频系统做了讨论,而后重点研究了匹配滤波器法的原理及其功能,研究了利用数字匹配滤波器法对扩频码序列进行同步捕获,从而解决了在扩频系统中对伪码的快速捕获,并在Altera公司的Quartus Ⅱ软件平...     

Graph theoretical considerations of channel offset systems in acellular mobile system

The problem of assigning channels in a channel-offset-type of cellular mobile radio communication system is formulated as a problem of assigning channels to the vertices of a network. It is shown that the assignment problem in a network is a generalized graph coloring problem. When the interchannel interference function is a rational number, the optimal channel offset scheme is obtained. and upper and lower bounds of the minimum total bandwidth in a channel-offset scheme are derived. These factors give basic and useful knowledge for designing a channel-offset system of a cellular mobile system, and they are useful not only for a fixed channel assignment but also for a dynamic channel assignment and rearrangement     

Energy‐Efficient Power Allocation for Cognitive Radio Networks with Joint Overlay and Underlay Spectrum Access Mechanism

Traditional designs of cognitive radio (CR) focus on maximizing system throughput. In this paper, we study the joint overlay and underlay power allocation problem for orthogonal frequency‐division multiple access–based CR. Instead of maximizing system throughput, we aim to maximize system energy efficiency (EE), measured by a “bit per Joule” metric, while maintaining the minimal rate requirement of a given CR system, under the total power constraint of a secondary user and interference constraints of primary users. The formulated energy‐efficient power allocation (EEPA) problem is nonconvex; to make it solvable, we first transform the original problem into a convex optimization problem via fractional programming, and then the Lagrange dual decomposition method is used to solve the equivalent convex optimization problem. Finally, an optimal EEPA allocation scheme is proposed. Numerical results show that the proposed method can achieve better EE performance.     

A Cost-Based Availability Allocation Algorithm

This paper develops a cost-based procedure for allocating the availability parameters (repair times and failure rates) to the various components that make up a system. The allocation is handled as a cost minimization problem, subject to the constraint of meeting a system availability requirement. The problem is solved using Lagrange multipliers and an example is stated and solved. This technique is applicable in the early stages of system design to determine the detailed component availability specifications (repair times and failure rates) that will allow a system requirement to be met. Furthermore, the technique is useful in the latter stages of system design when initial specifications have fallen short of the required goal, and modifications and improvements are required. The technique points out the problem components and defines the amount of improvement necessary.     

Resource allocation algorithm in LTE uplink SC-FDMA system for time-varying channel with imperfect channel state information

In long term evolution (LTE) uplink single carrier frequency division multiple access (SC-FDMA) system, the restriction that multiple resource blocks (RBs) allocated to a user should be adjacent, makes the resource allocation problem hard to solve. Moreover, with the practical constraint that perfect channel state information (CSI) cannot be obtained in time-varying channel, the resource allocation problem will become more difficult. In this paper, an efficient resource allocation algorithm is proposed in LTE uplink SC-FDMA system with imperfect CSI assumption. Firstly, the resource allocation problem is formulated as a mixed integer programming problem. Then an efficient algorithm based on discrete stochastic optimization is proposed to solve the problem. Finally, simulation results show that the proposed algorithm has desirable system performance.     

Comparative analysis of the Lyapunov function for different strategies of analogue circuits design

Generalized methodology has been developed for analogue circuits design based on applying the optimal control theory. The problem of time optimal system design was defined as a classical functional optimization problem of the optimal design theory. In this case the process of analogue circuits design is mathematically defined as a dynamic control system. In this context the minimization problem of the processor time of designing can be formulated as a minimization problem of the response time of dynamic system. In order to analyze the properties of such a system, it is proposed to use the concept of the Lyapunov dynamic system function. Using this function and its time derivative a special function has been built that allows us to predict the total processor time of circuit design by using the characteristics of the initial period of designing. Numerical results indicate the possibility of predicting the processor time of different design strategies in terms of the special function behavior.     

基于约束总体最小二乘的单站DOA/TDOA联合误差校正与定位算法

多基外辐射源雷达定位系统受系统偏差影响较大。该文针对多基外辐射源雷达到达角度(DOA)和到达时差(TDOA)联合定位系统,提出一种基于约束总体最小二乘(CTLS)的无源定位和误差校正算法。首先引入辅助变量,将DOA和TDOA非线性观测方程进行线性化处理。考虑伪线性化后定位方程中噪声矩阵各分量统计相关特性,将无源定位与误差校正联合优化问题建立为CTLS模型,并采用牛顿迭代方法对模型求解。在此基础上,考虑辅助变量与目标位置的关联性,设计关联最小二乘算法改进目标位置估计值,采用后验迭代方法进一步提高系统偏差估计精度。最后推导了算法的理论误差。仿真结果表明:该算法能够有效地估计目标位置和系统偏差。     

Using Linear Relations Between Experimental Characteristics in Stiff Identification Problems of Linear Circuit Theory

The paper treats an inverse problem posed in the time domain for a circuit described by a stiff system of ordinary differential equations (ODEs). Identification of model parameters (circuit elements) is performed by processing transient characteristics measured in the circuit. An illustrative example discussed throughout the paper shows that reducing the identification problem to curve fitting, which is the most general way, may be hardly used for a stiff model due to a ravine shape of the objective functional. Moreover, a necessity of solving the stiff ODE system to get a functional value makes the inverse problem be practically unsolvable. It has been shown that the initial inverse problem may be simplified significantly by taking into account linear relations which are observed between the experimental characteristics measured for a stiff system. The relation coefficients are discussed in the paper with regard to the accuracy of the approximation. Finally the initial identification problem has been reduced to a nonlinear system of algebraic equations which may be easily solved considering different sensitivity of the relation coefficients to the model parameters. The final solution is presented for different levels of "measurement" error involved in the simulation.     

不准确CSI下智能反射表面辅助的多用户系统物理层安全方案设计

该文研究智能反射表面(Intelligent Reflecting Surface, IRS)辅助的多用户下行系统中的物理层安全的优化问题。多个用户之间的信息需要相互保密,每个时隙,非信息传输的目标用户视为窃听者,因此这是一个多窃听者的安全传输系统。由于信道的时变性,基站拥有窃听信道的信道状态信息(Channel State Information,CSI)为与真实的CSI间存在误差的过时信息。在此条件下,以系统最坏情况下的保密速率最大化为目标,对基站发射信息信号和人工噪声波束成形矢量,以及IRS的相移矩阵进行联合优化。原始优化问题为非凸半正定规划问题,利用松弛变量、惩罚函数、Charnes-Cooper变换和交替迭代优化等方法将原问题转化为凸问题并求解。仿真结果显示,相较于基准方案,该文所提出的优化算法能有效提高系统的保密速率。     

二维H型四终端量子点阵列的量子输运

利用一个基于紧束缚模型的散射区格点上能量波动的二终端系统的透射和反射系数的一般计算方法,然后提出了基于实空间格点的H型四终端量子点阵列的系统,将其转化成二终端量子点阵列模型去探讨,通过利用实空间格林函数,计算了H型四终端量子点阵列的透射率,研究其量子输运问题。     

NETCAP: a capacity planning tool for practical content distribution network designs

This paper describes a capacity planning tool NETCAP, which is a prototype software program for automatically planning and integrating application‐specific content‐distribution networks (CDNs). The CDN integration problem consists of two problems: data management system design problem and network topology design problem. The data management system design problem comprises of the server placement and file allocation problems, where the network topology design problem involves determining the network topology with network technology considerations. The CDN integration problem has been formulated as an optimization problem; where the objective function is to optimize a network topology that satisfies both the servers' access requirements and clients' communications. An evolutionary technique is used in NETCAP to search the design space. The experimental results for a CDN integration problem described here demonstrate the effectiveness of NETCAP in finding good CDN designs from a large design space in a few minutes. Copyright © 2006 John Wiley & Sons, Ltd.     

一种旋转式相位干涉仪测角系统研究

相位干涉仪测角是反辐射雷达导引头较常采用的一种测向体制,通常采用长、短基线的方式解决测角模糊问题。论述一种旋转式干涉仪测角系统能够利用弹体自身旋转解决测角模糊问题,通过数字仿真说明了该系统的正确性。该系统中可变延迟线的特性直接影响测角性能,提出的数字化方案能够较好地解决该问题。     

基于效用最大化的IEEE 802.11 DCF性能分析及改进

针对802.11 DCF在系统负载较大时不能有效利用带宽资源的缺点,该文提出一种基于效用函数的DCF优化机制(U-DCF)。通过设置站点吞吐量的对数效用函数,将带宽资源的有效利用问题建模为系统效用最大化问题;应用最优化理论将此系统问题等效为可分布式求解的用户问题,即各站点只须独立选择最大化其净效用的竞争参数(CWmin),则系统整体效用也获得最大化。仿真结果表明:与标准DCF相比,U-DCF通过预估系统的当前平均分组长度和竞争站点数来调整竞争参数CWmin,能够显著提高系统的饱和吞吐量,减小分组发送时延和丢帧率。     

An interactive authoring system for video object segmentation and annotation

An interactive authoring system is proposed for semi-automatic video object (VO) segmentation and annotation. This system features a new contour interpolation algorithm, which enables the user to define the contour of a VO on multiple frames while the computer interpolates the missing contours of this object on every frame automatically. Typical active contour (snake) model is adapted and the contour interpolation problem is decomposed into a two-directional contour tracking problem and a merging problem. In addition, new user interaction models are designed for the user to interact with the computer. Experiments indicate that this system offers a good balance between algorithm complexity and user interaction efficiency.     

码分多址系统中的多用户检测

CDMA通信系统是一个自干扰受限系统，如何克服CDMA系统中的多址干扰问题已成为提高CDMA系统容量的关键。多用户检测是克服CDMA多址干扰最有潜力的关键技术之一。本文研究了CDMA移动通信系统中几种常见的多用户检测技术，分析了他们的原理，并对各种多用户检测的优缺点进行了比较。     

被动传感器系统分层快速关联算法

被动传感器系统的核心问题是测量数据关联问题.在被动传感器系统中,多维分配算法是一种有效的关联算法,但多维分配本身是一个NP-hard问题并且建立候选分配树需耗费大量时间.为解决被动传感器系统中测量数据快速关联问题,本文提出了分层快速关联算法.该算法通过统计量检验减少候选关联,分层搜索寻找正确关联.仿真实验结果表明,分层快速关联算法是一种有效的关联算法,正确关联率高于拉格朗日松驰算法.     

基于FPGA的相控阵雷达波控系统设计

为了解决目前相控阵雷达波控系统的处理速度问题，提出了一种基于FPGA的雷达波控系统设计方法。阐述了如何利用DSP Builder设计波控系统运算模块，并对设计过程中关于资源优化和算法改进等问题进行了详细介绍，最后通过对仿真结果深入分析和对比发现，该系统完全满足现有大型平面相控阵雷达波控系统的速度要求，具有一定的普适性和推广价值。