Application of Bernstein Expansion to the Solution of Control Problems

We survey some recent applications of Bernstein expansion to robust stability, viz. checking robust Hurwitz and Schur stability of polynomials with polynomial parameter dependency by testing determinantal criteria and by inspection of the value set. Then we show how Bernstein expansion can be used to solve systems of strict polynomial inequalities.     

嵌入式系统程序优化方法的研究

嵌入式系统往往对实时性、系统功耗和程序代码长度有特殊的要求，本文从程序设计的角度讨论满足这些要求的程序代码优化方法。文中首先讨论了程序执行时间的优化方法，随后讨论了程序代码长度的优化方法，最后讨论了程序功耗的优化方法。     

Applications of Symbolic Execution to Program Testing

The advanced method of symbolic evaluation can be applied to program testing situations with results close to those of formal correctness proofs–but without the high cost.     

Formalization of Bernstein Polynomials and Applications to Global Optimization

This paper presents a formalization in higher-order logic of a practical representation of multivariate Bernstein polynomials. Using this representation, an algorithm for finding lower and upper bounds of the minimum and maximum values of a polynomial has been formalized and verified correct in the Prototype Verification System (PVS). The algorithm is used in the definition of proof strategies for formally and automatically solving polynomial global optimization problems.     

Symbolic Semantics and Program Reduction

A class of transformations of functional programs based on symbolic execution and simplification of conditionals is presented. The operational symbolic semantics of a family of functional languages is defined exploiting a set-theoretic notion of symbolic constants. An effective transformation able to simplify a functional program via removal of conditionals is discussed. Finally, it is shown that a structural approach, based on abstract data type specifications, provides a suitable representation for symbolic constants.     

An Approach to Reachability Determination for Static Analysis Defects with the Help of Dynamic Symbolic Execution

Programming and Computer Software - Program analysis methods for error detection are conventionally divided into two groups: static analysis methods and dynamic analysis methods. In this paper, we...     

Program Behavior at the Symbolic Level

No application programmer writes machine-language programs–i.e., strings of ones and zeroes. That primitive pursuit has long been reserved for those few who create the very first modules of a software system for new hardware. Instead, programmers make use of a wide spectrum of symbolic programming languages, ranging from assembly code to high-level languages such as Fortran, Cobol, and the Algol family. Every programming language has semantics which define some abstract machine. For the assembly-language programmer this machine bears a great resemblance to the actual hardware on which the program will be interpreted, but even here the programmer will frequently use system-defined subroutines or macros which represent extensions of the base hardware facilities. The high-level language programmer's abstract machine reflects the control mechanisms and data structures characteristic of the language. The Fortran programmer, for example, can think in terms of multidimensional array structures, DO loops, subprogram facilities, and so on. In principle he need never be concerned with the manner in which his abstract Fortran machine is to be realized by a particular hardware and software system. The user of a modern electronic hand calculator needs no knowledge of the works inside the box, and a modern high-level language system should present to its users an equally consistent environment, completely defined in terms of the syntax and semantics of the source language.     

An Approximate Simulation Approach to Symbolic Control

This paper introduces a methodology for the symbolic control of nonlinear systems based on an approximate notion of simulation relation. This notion generalizes existing exact notions of simulation and is completely characterized in terms of known stabilizability concepts. Equipped with this notion we show how, under certain stabilizability assumptions, we can construct finite or symbolic models for nonlinear control systems. Synthesizing controllers for the original control system can then be done by using supervisory control techniques on the finite models and by refining the resulting finite controllers to hybrid controllers enforcing the specification on the original continuous control system. The proposed design methodology can be seen as a correct-by-design way of obtaining both the feedback control laws as well as the control software responsible for deciding which law is executed and when.      

PVM并行程序向GAMMA迁移的方法

首先分析了PVM消息传递的通信机制以及影响其通信效率的原因,然后介绍了一种基于主动消息技术的通信系统GAMMA。在此基础上提出了将PVM程序迁移到GAMMA的方法。     

Space-Time Domain Expansion Approach to VLSI and Its Application to Hierarchical Scene Matching

VLSI technology has recently received increasing attention due to its high performance and high reliability. Designing a VLSI structure systematically for a given task becomes a very important problem to many computer engineers. In this paper, we present a method to transform a recursive computation task into a VLSI structure systematically. The main advantages of this approach are its simplicity and completeness. Several examples, such as vector inner product, matrix multiplication, convolution, comparison operations in relational database and fast Fourier transformation (FFT), are given to demonstrate the transformation procedure. Finally, we apply the proposed method to hierarchical scene matching. Scene matching refers to the process of locating or matching a region of an image with a corresponding region of another view of the same image taken from a different viewing angle or at a different time. We first present a constant threshold estimation for hierarchical scene matching. The VLSI implementation of the hierarchical scene matching is then described in detail.     

The Qualified Function Approach to Analysis of Program Behavior and Performance

The notion of a qualified function is introduced as a general means of representing the parameters of dynamic systems. Two specific types of qualified functions are defined for the analysis of the behavior and performance of structured programs. Transformation functions represent the values of variables during execution and timing algorithms express the execution times of programs symbolically. Complete rules of derivation for transformation functions and timing algorithms are given for the control mechanisms of sequence, selection, fixed loop, and while statement. Deterministic and stochastic simplification of transformation functions and timing algorithms are investigated and methods of eliminating recursion for expressions corresponding to while statements are studied.     

进化算法与符号执行结合的程序复杂度分析方法

程序的最坏执行路径是计算程序复杂度的一项重要指标,有助于发现系统可能存在的复杂性漏洞.近年来将符号执行应用于程序复杂度分析的研究取得了不小的进展,但现有方法存在通用性较差、分析时间较长的问题.文中提出一种面向最坏路径探测的进化算法——EvoWca,其核心思想是利用程序在较小输入规模下的已知最坏路径特征指导较大输入规模下初始路径集合的构建,然后模拟进化算法,对路径进行组合、突变和选择迭代,使得在搜索范围内探测到的最坏路径逼近于最坏时间复杂度对应的路径.基于该算法实现了一个用于程序复杂度分析的原型工具EvoWca2j,使用该工具和已有技术对一组Java程序进行最坏路径探索和执行效率评估,实验结果表明,相比现有方法,EvoWca2j的通用性和探索效率都有明显提高.     

A Symbolic Approach to Freeform Parametric Surface Blends

This paper presents a symbolic approach to the computation of blend surfaces across piecewise polynomial and rational surfaces. Curves in the parameter space of the primary surfaces can be specified as the rail curves, also known as trimlines, of the blend. Several techniques which require various levels of user interaction are presented for defining the cross-boundary tangent curves along the rail curves. The resulting blend is represented as a polynomial surface having tangent plane continuity with the primary surfaces to an accuracy bounded only by the machine precision. Also presented is a normalization method that approximates unit vector fields, an approach that might benefit other applications such as offset approximation and animation curve construction. © 1997 by John Wiley & Sons, Ltd.     

高校计算机实验室网络防护初探

计算机和网络两者在当今飞速发展,高校计算中心的发展却总是比较滞后.而企业的网络安全问题由来已久.所以对于企业级别的网络管理模式结合计算中心的实际情况进行了研究,从软、硬、管三方面入手,找到了一条科学配置中心人力资源、硬件资源和管理资源,从而更好的让网络资源给教学和科研服务之路.     

C 在聚类分析中的应用

本文主要介绍了聚类分析的K-MEANS算法,并且给出了K-MEANS算法的C 实现,最后通过一个实例加以说明.     

中国京剧艺术符号解析及延伸应用

本论文以京剧文化为对象,从分析符号学理论系统与京剧艺术的本质联系开始,重点阐述了京剧作为国粹存在的价值,京剧艺术中符号特性的表现以及京剧艺术符号的意指关系。并结合北京奥运的时代背景,初步探讨了北京08奥运背景下进行京剧文化的创意设计。     

Bacterial Foraging Optimization Approach to Portfolio Optimization

In this paper we propose a heuristic approach based on bacterial foraging optimization (BFO) in order to find the efficient frontier associated with the portfolio optimization (PO) problem. The PO model with cardinality and bounding constraints is a mixed quadratic and integer programming problem for which no exact algorithms can solve in an efficient way. Consequently, various heuristic algorithms, such as genetic algorithms and particle swarm optimization, have been proposed in the past. This paper aims to examine the potential of a BFO algorithm in solving the PO problem. BFO is a new swarm intelligence technique that has been successfully applied to several real world problems. Through three operations, chemotaxis, reproduction, and elimination-dispersal, the proposed BFO algorithm can effectively solve a PO problem. The performance of the proposed approach was evaluated in computational tests on five benchmark data sets, and the results were compared to those obtained from existing heuristic algorithms. The proposed BFO algorithm is found to be superior to previous heuristic algorithms in terms of solution quality and time.     

3D SoC测试结构优化与测试调度的博弈模型

硅通孔技术是实现三维系统芯片的一种新兴的方法.而作为测试基础,测试访问机制和测试外壳则方便了三维系统芯片模块化测试,测试结构优化问题是研究的热点.提出基于博弈论的3D SoC测试结构优化技术,使基于核的三维系统芯片测试时间最少,TAM带宽最大,并且满足TSV数目约束.提出的方法利用二人合作博弈论方法的优点,对测试结构和测试调度问题进行建模,给出了基于博弈实现3D SoC测试结构优化的算法.用ITC02 SoC测试基准电路搭建成堆叠SoC,并在其上对提出的算法进行了模拟.实验结果显示,与之前的2D IC上开发的方法相比较,本文提出的测试结构优化与测试调度方法结果更优越.     

复杂电路分析的最优化程序方法与应用

应用最优化基本原理,提出了以支路电流和节点位为设计变量,以电路平衡条件为目标函数的任意复杂电路分析的框架式目标函数化程序方法,该方法所构造的框架式目标函数,将根据具体电路输入参数,合理地设计变量分配与排序和完成目标函数的累积运算,可快速实现任意组合电路的分析计算。电路问题算例验证了这种程序方法的可行性和通用性。