遗传算法在舰载机弹药转运任务优化配置中的应用

针对舰载机弹药转运任务要求特殊,建立了优化模型。将任务配置方案模型合理地描述为遗传算法的表达形式,并对其操作因子进行改进,得到了最优的转运任务配置方案。实例仿真结果验证了优化配置模型的正确性,以及改进遗传算法的有效性。     

构形冗余概念及传感器系统冗余综合评估与配置

复杂控制系统中存在大量不同机理和作用方式的功能和硬件冗余,主动开发和配置这 种冗余是控制系统设计的重要课题.本文提出新的"构形冗余"概念,对不同的系统冗余提供了统 一的理解角度和通用冗余指标,可以综合评价系统中蕴涵的各种冗余,因而指导对这些冗余的统 一配置,提供新的系统主动生存性设计依据.构形冗余概念被具体用于传感器系统,给出了其构 形冗余指标的具体计算方法,并通过若干实例验证了上述方法在冗余综合评估与配置中的应用 效果.     

基于UML与CCSP的产品配置方法

为了有效开发易维护可重用的产品配置模型以及实现配置问题的快速求解,提出了结合面向对象建模技术与条件约束满足问题理论的产品配置方法。给出了条件约束满足问题理论模型;提出了基于统一建模语言和条件约束满足问题的产品配置建模与求解方法;通过定义统一建模语言表示的产品配置概念模型与条件约束满足问题之间的映射规则集,建立了基于条件约束满足问题的产品配置模型。以某可配置医用监测器为应用实例,阐述了所提方法应用于配置模型构建与求解的可行性和有效性。     

满足货物承载能力约束的集装箱装载问题研究

本文采用基于矩阵的货物空间约束表达形式和货物承载能力约束表达形式以及简单块生成策略,对基于Beam Search算法的集装箱装载算法进行了改进,以使其能够有效进行满足货物承载能力约束的集装箱装载问题的优化计算,实验结果表明了该算法的有效性。     

面向产品线交互配置不一致性修复的差分IBEA算法

在大规模复杂系统产品线工程中,人工配置难免会导致配置的不一致,即,配置数据会违背预定义的约束(也可以称为一致性约束).对于大规模复杂系统产品线体系结构,比如信息物理系统产品线,往往存在成百上千的可变点以及约束,而且约束与可变点之间存在复杂的依赖关系,为不一致配置的修复带来很大的挑战.为了解决这个问题,针对前期提出的基于多目标搜索以及约束求解技术的自动不一致配置修复推荐框架(Zen-Fix),提出一种改进的IBEA算法(De IBEA).De IBEA通过将差分引入IBEA算法,搜索过程中,基于可行解和不可行解的差分变异产生后代,最终为用户推荐符合预定义约束并且对于配置效率来说最优的配置修复方案.基于一个工业案例海底油田采控系统产品线为例,通过模拟一个产品的配置过程,产生了10 189个优化问题,结果表明:Zen-Fix框架结合De IBEA算法,可以实时地为用户提供较优的不一致配置修复方案.此外,通过对这10 189个问题的推荐方案进行对比,证明了De IBEA算法无论从时间效率还是搜索性能上都优于原始的IBEA算法.     

基于隐实体建模模式的分布式约束数据库系统

在传统对象关系数据库中采用扩充基于隐实体建模模式的空间逻辑运算和空间分析运算功能,建立了用于虚拟现实应用的分布式约束数据库系统。隐实体建模模式采用符号表达式方法表达空间物体,提高了数据的表现力,消除了数据冗余,减少了记录的数量,处理空间数据的实时性显著增强。采用与关系数据一致的空间数据表达形式可将空间数据与关系数据一同存储,保证了数据的完整性。构造树方式管理隐实体数据使数据库中物体间的空间逻辑关系的表达更清晰,空间分析和运算更简洁。     

工作流技术在基于web的信息资源审核流程中的应用

现有的内容管理系统的资源审核功能相对简单,面对非结构化数据时难以实现过程可配置、人员可调整的审核过程,严重影响了系统效率。本文在对现有审核机制的缺点及存在问题进行分析的基础上,提出了一种引入了流程驱动思想的审核模型,对资源审核进行了重新划分和定义,以XML作为审核过程描述文档,实现灵活有效并可配置的审核,进而在分析模型过程中给出实例并进行总结。     

Vague熵的约束准则及计算公式

通过对Vague集的模糊度本质进行分析,结合现有的Vague熵的约束准则,给出了改良的Vague熵的约束准则以及能够体现未知性和模糊性的Vague熵公式,并通过实例验证其合理性.     

元组关系演算的语义研究

针对一些文献存在的问题，规范了特性谓词在元组关系演算中的表达形式，研究了完整性约束及空值对元组关系演算语义的影响，并通过实例加以说明。     

分布式数据库服务器系统及其自适应配置管理策略

服务器冗余技术在解决传统分布式环境的可用性和性能瓶颈问题的同时,给系统的管理带来了新的挑战．介绍了一种分布式数据库服务器DDSS的构成原理及工作模型．为了解决当前冗余服务系统的配置管理中存在的冗余资源动态可扩展性不强的问题,针对服务器DDSS(模型把系统中的每种服务抽象成为一个对象类,并提出同一个服务对象类的多个实例互为冗余服务),对冗余资源的配置管理问题进行讨论,并提出基于移动代理技术的自适应配置管理ACM(adaptive configuration management)策略,在保证系统可用性的前提下提高系统的性能,减少资源浪费．在ACM中,通过定义奖惩函数(对于静态配置)和用户请求到达率(对于动态配置)来作为配置依据,对冗余实例进行动态增加或删除．最后,对算法的性能进行了分析、测试,并与传统算法进行了比较．     

A dynamic constraint satisfaction approach for configuring structural products under mass customization

Configuring structured products poses new challenges to the solving technologies for product configuration. This paper presents a novel and direct approach to encoding configuration models into the Dynamic Constraint Satisfaction Problems (DCSP). In the presented approach, components are encoded as DCSP variables while structural relationships are represented as DCSP activity constraints. Furthermore, the configuration constraints such as the requisition and exclusion constraints are treated as DCSP compatibility constraints, which allow a low-level component to join in the solving process only after its high-level component is selected in the configuration. The presented method allows a more compact encoding representation, compared to CSP and generative CSP. Experimental study shows that the presented DCSP encoding approach makes a significant improvement in the performance of product configuration.     

Extended object model for product configuration design

This paper presents an extended object model for case-based reasoning (CBR) in product configuration design. In the extended object model, a few methods of knowledge expression are adopted, such as constraints, rules, objects, etc. On the basis of extended object model, case representation model for CBR is applied to product configuration design system. The product configuration knowledge can be represented by the extended object. The model can support all the processes of CBR in product configuration design, such as case representation, indexing, retrieving, and case revising. The presented model is an extension of the traditional object-oriented model by including the relationship class used to express the relation between the cases, constraints class used in the product configuration knowledge representation, index class used in case retrieving, and solution class used in case revising. Therefore, the product configuration knowledge used in the product configuration design can be represented by using this model. In the end, a metering pump product configuration design system is developed on the basis of the proposed product configuration model to support customized products.     

串并联系统中支持实时替换的混合冗余策略优化

在需要长时间可靠运行的软件系统中,由于持续运行时间和任务响应速度的要求增加,工作组件在被探测到失效后将被冗余组件实时替换.但现有可靠性优化研究通常假设冷备份冗余在所有积极冗余组件失效后才使用.针对支持实时替换的混合冗余策略,对其冗余度优化分配进行研究.该策略不仅能够保障系统可靠性,而且能够保障系统性能,故选用实时可用性和任务完成效率两类约束条件,建立冗余配置代价最小化模型.基于马尔可夫链理论对可靠性及性能两类系统指标进行定量分析;采用数值计算方法对非线性的状态分析模型进行计算;改进二元组编码遗传算法对上述优化问题进行求解.采用实例对串并联系统中实时可用性及任务完成效率的分析进行了说明,并对优化冗余分配模型进行了验证.实验结果表明,在相同冗余度下,支持实时替换的混合冗余策略在任务完成效率方面优于传统的混合冗余策略.所以,在相同约束条件下不同混合冗余策略需要采用不同的冗余优化配置方案.     

基于AOP架构的业务约束检测

利用运行时验证这样一种新兴的轻量级验证技术和AOP的框架结合,检测业务约束之间存在的冗余和冲突。首先对业务约束进行定义,利用约束理论（TOC）中的现实树（RT）将约束提取出来放在AOP的切入点（pointcut）中,然后利用命题语言表示约束的监控性质,再通过合并真值表的方法来检测约束中存在的冗余和冲突,最终提高软件的可靠性。     

Modelling distributed crewing in commercial aircraft with STAMP for a rapid decompression hazard

Abstract

Changes to crewing configurations in commercial airlines are likely as a means of reducing operating costs. To consider the safety implications for a distributed crewing configuration, system theoretic accident model and processes (STAMP) was applied to a rapid decompression hazard. High level control structures for current operations and distributed crewing are presented. The CONOPS generated by STAMP-STPA for distributed crewing, and design constraints associated with unsafe control actions (UCAs) are offered to progress in the route to certification for distributed crewing, and improve safety in current operations. Control loops between stakeholders were created using system-theoretic process analysis (STPA). The factors leading to the Helios 255 incident demonstrated the redundancy that a ground station could offer without the risk of hypoxia, during a decompression incident. STPA analysis also highlighted initial UCAs that could occur within the hypothetical distributed crewing configuration, prompting consideration of design constraints and new CONOPS for ground station design.

Practitioner Summary: SPO in commercial aircraft is likely as a means to reduce costs. This paper makes a case for distributed crewing using STAMP-STPA. Comparing current operations with a distributed crewing configuration, the redundancy offered by a ground station is demonstrated. Design constraints and new CONOPs for distributed crewing, and current operations are proposed.     

Formal properties of net-based knowledge representation schemes

In the spirit of integrating database and artificial intelligence techniques, a number of concepts widely used in relational database theory are introduced in a knowledge representation scheme. A simple network model, which allows the representation of types, is-a-relationships and disjointness constraints is considered. The concepts of consistency and redundancy are introduced and characterized by means of implication of constraints and systems of inference rules, and by means of graph theoretic concepts.     

Identifying redundancy in multi-dimensional knapsack constraints based on surrogate constraints

Redundancy identification techniques play an important role in improving the solvability of a linear program. In this paper, we address the redundancy in multi-dimensional knapsack constraints by proposing a new redundancy identification method. The proposed method is based on the constraint intercepts of Paulraj, Chellappan, and Natesan [A heuristic approach for identification of redundant constraints in linear programming models, Int. J. Comput. Math. 83 (2006), pp. 675–683] and surrogate constraints. In it, feasibility problems are constructed in order to determine the redundancy of the constraints, and are solved by a heuristic algorithm, which is developed to check the redundancy fast. The results of computational experiments show that the proposed method may be used in a preprocessing stage in order to reduce the number of knapsack constraints.     

Evolving structural design solutions using an implicit redundant Genetic Algorithm

Performing synthesis during conceptual design provides substantial cost savings by selecting an efficient design topology and geometry, in addition to selecting the structural member properties. A new evolutionary-based representation, which combines redundancy and implicit fitness constraints, is introduced to represent and search for design solutions in an unstructured, multi-objective structural frame problem. The implicit redundant representation genetic algorithm, in tandem with the unstructured problem domain definition, allows the evaluation of diverse frame topologies and geometries. The IRR GA allows the representation of a variable number of location independent parameters, which overcomes the fixed parameter limitations of standard GAs. The novel frame designs evolved by the IRR GA synthesis design method compare favourably with traditional frame design solutions calculated by trial and error. Received May 27, 1999     

Implicit representation in genetic algorithms using redundancy

A new representation combining redundancy and implicit fitness constraints is introduced that performs better than a simple genetic algorithm (GA) and a structured GA in experiments. The implicit redundant representation (IRR) consists of a string that is over-specified, allowing for sections of the string to remain inactive during function evaluation. The representation does not require the user to prespecify the number of parameters to evaluate or the location of these parameters within the string. This information is obtained implicitly by the fitness function during the GA operations. The good performance of the IRR can be attributed to several factors: less disruption of existing fit members due to the increased probability of crossovers and mutation affecting only redundant material; discovery of fit members through the conversion of redundant material into essential information; and the ability to enlarge or reduce the search space dynamically by varying the number of variables evaluated by the fitness function. The IRR GA provides a more biologically parallel representation that maintains a diverse population throughout the evolution process. In addition, the IRR provides the necessary flexibility to represent unstructured problem domains that do not have the explicit constraints required by fixed representations.     

基于有向超图的参数代表示模型及其实现

本文提出了一种基于有向超图的参数化图形表示模型．它不仅能够表示图形的尺寸约束和几何约束，而且能够支持图形拓扑结构变化和工程设计约束的表示．在交互绘制图形对象的同时直接建立参数化图形约束模型．由于在图形构造的每一步都保证约束的一致性，因此，不会出现过约束或欠约束的情况．经实践表明，该模型具有实用方便、高效可行的特点，适合于系列化产品的参数化ＣＡＤ系统建模和绘图．