Reachability determination in acyclic Petri nets by cell enumeration approach

Reachability is one of the most important behavioral properties of Petri nets. We propose in this paper a novel approach for solving the fundamental equation in the reachability analysis of acyclic Petri nets, which has been known to be NP-complete. More specifically, by adopting a revised version of the cell enumeration method for an arrangement of hyperplanes in discrete geometry, we develop an efficient solution scheme to identify firing count vector solution(s) to the fundamental equation on a bounded integer set, with a complexity bound of O((nu)^n−m), where n is the number of transitions, m is the number of places and u is the upper bound of the number of firings for all individual transitions.     

Optimization for limited angle tomography in medical image processing

This paper aims to reduce the problems of incomplete data in computed tomography, which happens frequently in medical image process and analysis, e.g., when the high-density region of objects can only be penetrated by X-rays at a limited angular range. As the projection data are available only in an angular range, the incomplete data problem can be attributed to the limited angle problem, which is an ill-posed inverse problem. Image reconstruction based on total variation (TV) reduces the problem and gives better performance on edge-preserving reconstruction; however, the artificial parameter can only be determined through considerable experimentation. In this paper, an effective TV objective function is proposed to reduce the inverse problem in the limited angle tomography. This novel objective function provides a robust and effective reconstruction without any artificial parameter in the iterative processes, using the TV as a multiplicative constraint. The results demonstrate that this reconstruction strategy outperforms some previous ones.     

增强战斗力的有效途径:虚拟战争

在军事领域中,随着军事斗争的复杂性的不断增加,人们一直在寻求一种能在实验条件下“预先实践战争”的方法,来深入地研究未来战争的规律。现代科学技术的飞速发展,使得人们这一愿望得以实现。在虚拟现实技术基础上发展起来的“虚拟战争”方法,正是研究增强军队战斗力的有效途径。本文对这一课题作了概要的阐述。     

B/S模式应用系统的一种新型结构及其实现

由于目前Ｂ／Ｓ模式应用系统的缺陷,提出了一种新型的系统结构并从原理上阐述了它的合理性,最后从模块间的通信。处理线程和数据库操作程间的同步和互斥以及系统等方面讲述系统的实现。     

Control theoretic smoothing splines

Some of the relationships between optimal control and statistics are examined. We produce generalized, smoothing splines by solving an optimal control problem for linear control systems, minimizing the L²-norm of the control signal, while driving the scalar output of the control system close to given, prespecified interpolation points. We then prove a convergence result for the smoothing splines, using results from the theory of numerical quadrature. Finally, we show, in simulations, that our approach works in practice as well as in theory     

计算机犯罪侦查途径的探讨

近年来计算机犯罪案件呈迅速增长趋势,为有效控制和侦破此类案件,急需寻找一套行之有效的侦查办案途径.归纳各种犯罪手段,分别针对单机犯罪、专用网络犯罪和互联网犯罪,提出三种解决方案.     

实时信息系统的虚拟分层设计方案

本文借助软件系统分层设计的思想,提出了虚拟层的概念,并给出了一个实时信息系统虚拟分层设计方案,这为实际应用中各种规模的系列系统提供了一个组态灵活的开发方法。实践证明,这个方案取得了很好的效果,并具有很强的灵活性。     

智能仪表的可靠性设计与评估技术

本文主要探讨智能仪表设计中最常采用的几种可靠性设计技术及其具体应用,详细介绍了其中的可靠性预计与可靠性分配技术具体方法和步骤,比较了现有的几种可靠性评估技术.     

Output intersampling approach to direct closed-loop identification

A new direct closed-loop identification method, which uses the output intersampling technique, is proposed in this note. By using the intersampled plant input-output data, the proposed method removes the traditional restrictive identifiability condition, and does not require an external persistently exciting (PE) test signal