浅论建设项目投资控制的重点

建设项目控制的重点应放在投资决策和设计阶段中,否则会造成巨大的损失。这不仅需要人们改革组织结构和管理体制,更需要从根本上转变思想观念。     

An integer concave minimization approach for the minimum concave cost capacitated flow problem on networks

Formulating the minimum concave cost capacitated network flow problem as an integer concave minimization problem, we establish finite branch and bound algorithms, in which the branching operation is the so–called integral rectangular partition and the bounding procedure is performed by the classical minimum linear cost flow problem on subnetworks. For the special case that the flow cost function is concave on a fixed number of arcs and linear on the others, an upper bound of the running time is given. Received: 19 July 1996 / Accepted: 8 July 1997     

软件开发成本估算模型的研究

软件成本准确地估算和管理控制是软件项目开发成功的基础。该文分析了影响软件开发成本估算准确性的因素,并详细介绍了IBM模型、Putnam模型和COCOMO模型三种经验估算模型,探讨了软件开发成本估算的新需求。     

基于马尔科夫链的组密钥更新代价分析方法

组密钥管理机制大多基于树结构或星结构。在这两种结构中,成员的加入和离开均对密钥更新代价影响很大。提出基于连续时间马可夫链的代价更新分析方法,利用连续时间马可夫链来模拟成员动态变化,并对星结构和树结构的组播密钥管理方案进行更新代价仿真分析,并比较了两者的性能差异。仿真结果表明,组成员离开的概率和速率是影响星结构和树结构密钥管理方案在密钥更新代价上差异的主要因素。因此,在动态变化的环境下,应使用星结构和树结构相结合的组密钥管理机制。     

基于损失自注意力机制的立体匹配算法研究

针对现有的立体匹配算法在阴影、物体边缘和光照反射等区域匹配困难且存在大量错误结果的问题,设计了一种可拆卸的损失自注意力网络（loss self-attention net,LSAnet）查找图像中的匹配困难区域。LSAnet的网络各层相互稠密连接,应用了空洞卷积来扩大感受野,并以立体匹配算法生成的损失分布为标签,能够动态地进行有监督训练,最终生成匹配困难区域掩膜辅助立体匹配网络进行更好的优化;同时,改进了立体匹配网络中经典的特征匹配代价卷结构,降低了后续3D卷积的计算负荷,提高了匹配效率。实验结果表明,该算法相比于基准算法精度更高,并且可以提高算法对于匹配困难区域的鲁棒性。     

流域水电开发生态环保全过程管理探索

近年来,我国生态文明建设形势发生了根本性变化,国家对水电开发提出了更高的生态环保要求,只有加强建设项目环境影响评价事中事后的监管,才能形成了水电开发与生态环境和谐发展的流域水电开发新格局。笔者结合工程实际,从环保规划、体系建设、专项设计、措施落实、监督管理等角度,分析金沙江上游川藏段水电开发生态环保全过程管理的探索性工作,总结了建设单位强化自我监管、全面保障环保措施落实取得的初步成效,对推进“绿色水电”发展具有重要意义。     

沙特房建项目水电安装设计优化与成本控制探讨

以沙特阿美吉赞应急响应中心工程建设为例,阐述项目图纸会审阶段的设计优化处理、施工工艺、材料比选、安装方法等方面的成本控制措施,从而为今后类似工程施工提供参考和借鉴。     

Group technology based adaptive cell formation using predator-prey genetic algorithm

In recent years, there has been a considerable growth of application of group technology in cellular manufacturing. This has led to investigation of the primary cell formation problem (CFP), both in classical and soft-computing domain. Compared to more well-known and analytical techniques like mathematical programming which have been used rigorously to solve CFPs, heuristic approaches have yet gained the same level of acceptance. In the last decade we have seen some fruitful attempts to use evolutionary techniques like genetic algorithm (GA) and Ant Colony Optimization to find solutions of the CFP. The primary aim of this study is to investigate the applicability of a fine grain variant of the predator-prey GA (PPGA) in CFPs. The algorithm has been adapted to emphasize local selection strategy and to maintain a reasonable balance between prey and predator population, while avoiding premature convergence. The results show that the algorithm is competitive in identifying machine-part clusters from the initial CFP matrix with significantly less number of iterations. The algorithm scaled efficiently for large size problems with competitive performance. Optimal cluster identification is then followed by removal of the bottleneck elements to give a final solution with minimum inter-cluster transition cost. The results give considerable impetus to study similar NP-complete combinatorial problems using fine-grain GAs in future.     

一种新的修正恒模算法

阐述了恒模算法(CMA)、修正恒模算法(MCMA)和判决引导(DD)算法的基本原理。针对CMA和MCMA收敛速度慢,固定步长条件下收敛速度和剩余误差之间存在矛盾的缺陷,在分析CMA误差特性的基础上,利用DD算法误差函数的模值和判决器输出构造新的误差函数,提出了一种新的变步长MCMA。新算法在加快收敛速度的同时保持小的剩余误差。仿真结果表明,新算法比CMA和MCMA收敛速度快,均衡输出剩余码间干扰(ISI)小而且能克服相位偏移,具有很好的实用性。     

浅议进一步发挥军事代表在武器装备全寿命费用管理中的作用

阐述了军事代表参与武器装备全寿命费用管理的现状和作用,提出了提高军事代表费用管理参与率的措施.