Integrated Risk of Progress-Based Costs and Schedule Delays in Construction Projects

This article aims to explore the impact of the integration of risk factors into delayed milestones for construction projects. A simulation model was developed to determine the impact of schedule variability on cost estimation. To generate random scenarios a Monte Carlo Simulation (MCS) technique was applied. The developed model computes the cost impact of delayed milestone in the expected budget. Using a risk integration approach revealed the critical time frame that may lead to a budget deficit for a project. As a result, a number of cost-sensitive risk factors and schedule delays were identified for the critical time period where the risk of budget deficit increases. The method of integration proposed in this article highlights the priority of risk factors and schedule delays for construction contracts involving Payments at Event Occurrences (PEO). Consequently, the developed method can be useful for practitioners in anticipation of potential increase of costs, hence, prevention of failure due to budget deficit.     

浅海环境下的单-双基地联合声探测研究

浅海水域的高频声纳探测是近年来发展迅速、研究活跃的水声技术领域之一,它的研究为实现小目标的有效探测提供了重要的技术支撑。浅海声场存在多途干扰,会影响声纳探测的效果。本文介绍了一种单-双基地联合探测方法,并分析了浅海多途干扰对单-双基地联合探测的影响,最后用MATLAB进行仿真和分析。     

一种适用于移动节点的事件驱动分簇算法

提出一种适用于移动无线传感器网络节点的事件驱动分簇算法,使用簇头间能量筛选法选举簇头,并加入事件驱动机制,能够使节点在有突发事件发生的情况下,对网络中的簇进行基于事件区域的重组,以减少数据冗余。建立相应的仿真实验模型,对运动节点的分簇情况进行动态跟踪及分析。实验结果表明,该算法能够满足事件驱动分簇的要求,能量消耗比经典算法更均衡。     

基于空间和属性数据的联合索引技术

传统联合查询通常需要空间数据库对2个索引进行检索,通过集合运算得到最终结果,运算效率较低。针对该缺陷,提出基于空间和属性数据的联合索引技术,在索引目录项中加入属性数据提高联合检索速度。实验结果表明,该技术对于属性与空间位置有较高相关度的数据,具有较高查询效率。     

基于混合模型的CCD镜头畸变精校正算法

针对机器视觉检测和高精度图像测量中使用的CCD镜头都存在不同程度光学畸变的问题,提出基于混合模型的CCD镜头畸变校正算法。用经典模型对畸变图像进行初次校正,用多面函数拟合法进行二次精校正,用三次B样条函数进行灰度重建。实验结果表明,该方法在不依赖摄像机内部参数条件下,相比单一的镜头畸变校正模型,精度提高,鲁棒性增强,校正后径向均方根误差为0.3个像素。     

基于乘积季节模型的GPRS小区流量预测

针对GPRS小区流量预测问题,提出一种基于乘积季节自回归移动平均模型的解决方法。该方法分析GPRS小区流量的变化情况,利用小区流量以天为周期变化的特点,应用该模型进行建模,得到GPRS小区的流量变化预测模型。该预测模型可以根据GPRS小区过去的流量情况,预测将来某一时间的流量,为提前采取措施保持GPRS小区性能提供一定的决策依据。     

绘画艺术与心理的完美结合

艺术是一种用形象来反映现实但比现实有典型性的社会意识形态,而其中的绘画艺术作为一种非语言的沟通工具,可以让观察者了解语言文字无法揭示的东西,同时绘画艺术的存在是与心理完美结合着的,共同服务于人类社会。     

运输任务分配与路径选择的组合优化模型

针对运输任务分配与路径选择的组合优化问题,提出基于二维染色体结构的改进遗传求解算法。采用自然数编码,设计选择、交叉、变异、检查算子,以及算法的控制参数和算法终止条件,给出遗传算法的求解模型。开发基于C#的实验平台进行验证,结果证明,该算法具有较好的求解性能。     

Combined planning and scheduling in a divergent production system with co-production: A case study in the lumber industry

Many research initiatives carried out in production management consider process planning and operations scheduling as two separate and sequential functions. However, in certain contexts, the two functions must be better integrated. This is the case in divergent production systems with co-production (i.e. production of different products at the same time from a single product input) when alternative production processes are available. This paper studies such a context and focuses on the case of drying and finishing operations in a softwood lumber facility. The situation is addressed using a single model that simultaneously performs process planning and scheduling. We evaluate two alternative formulations. The first one is based on mixed integer programming (MIP) and the second on constraint programming (CP). We also propose a search procedure to improve the performance of the CP approach. Both approaches are compared with respect to their capacity to generate good solutions in short computation time.