基于CPM的项目时间定量分析的研究与应用

主要介绍CPM技术的概念和工作原理,分析旧有管理模式和技术手段的不足,提出CPM技术在项目进度控制和定量分析中的应用方法。通过一个实际的ERP项目给出了CPM技术在工程实践中的具体应用步骤。     

A novel time-depended evolutionary fuzzy SVM inference model for estimating construction project at completion

Construction projects frequently face cost overruns during the construction phase. Thus, a proactive approach is essential for monitoring project costs and detection of potential problems. In construction management, Estimate at Completion (EAC) is an indicator for assisting project managers in identifying potential problems and developing appropriate responses. This study utilizes weighted Support Vector Machine (wSVM), fuzzy logic, and fast messy Genetic Algorithm (fmGA) to handle distinct characteristics in EAC prediction. The wSVM is employed as a supervised learning technique that can address the features of time series data. The fuzzy logic is aimed to enhance the model capability of approximate reasoning and to deal with uncertainty in EAC prediction. Moreover, fmGA is utilized to optimize model's tuning parameters. Simulation results show that the new developed model has achieved a significant improvement in EAC forecasting.     

Accelerated simulation method for estimating the probability of functional failure in high-reliability systems

We consider a class of systems whose required performance is described by a stochastic process (t), t 0. An accelerated simulation method is proposed for estimating the probability that at some time instant t [0, T] the required performance exceeds the available performance. A numerical example is considered.Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 30–41, July–August, 1991.     

A simple method for estimating the duration of a resource-constrained project

In this paper, equations which relate the estimated duration of a resource-constrained project to functions of various, easily computed, network characteristics are developed and tested. Results are given for a total of 7978 single and multi-resource problems. These results indicate that in many cases a simple, easy-to-use equation could be employed in place of a sophisticated scheduling heuristic for estimating project duration.     

A novel hybrid method for improving ambulance dispatching response time through a simulation study

Response time is the most important factor in evaluating the performance of various Emergency Medical Services (EMS). In this paper, a novel hybrid method has been proposed to improve response time for ambulance dispatching. The proposed approach uses a linear hybrid metric based on network centrality measures, nearest neighbor method and first-in first-out (FIFO) policy. Other important parameters in ambulance dispatching such as the operating environment, rate of incoming emergency calls, available resources, hospitalization probability of the patients as well as distances and locations of units are all part of information used in this proposed approach. In line with the traditional metrics used in previous works, we have adopted a linear combined metric which is adjusted according to environment parameters. Results of extensive simulation experiments show reductions in response time by as much as 42% as compared to previous methods.     

A novel estimation method for failure-probability-based-sensitivity by conditional probability theorem

Structural and Multidisciplinary Optimization - By the average absolute difference between the unconditional failure probability and the conditional one on fixing an input at its realization, the...     

声矢量阵目标估计的新方法

矢量传感器的阵信号处理是研究矢量阵工程化应用的重要内容,但其运算量大.针对这一问题,提出了一种矢量阵的改进MMUSIC算法,该方法将维纳滤波引入到MMUSIC算法中,避免了矩阵的特征值分解,降低了运算量.采用矢量传感器均匀线阵研究该算法的性能,进行了仿真研究和实验验证.计算机仿真和实验结果表明:提出的算法可以清晰分辨相...     

A method for estimating the time intervals between transactions in speech-compression algorithms

A method is described for estimating the time intervals between transactions in speech-compression algorithms based on a complex Markov process, each state of which is a 2-parallel Markov process that describes the “competition” between the source of the signal that fills the buffer and the receiver of the signal that empties the buffer. The complex Markov process is transformed into an ordinary process, whose states simulate the number of buffer cells that are filled at the current time. This makes it possible to obtain a dependence connecting the probability of failure, the amount of buffer memory, and the mathematical expectations of the times of filling and emptying the buffer.     

Efficient numerical simulation methods for estimating fuzzy failure probability based importance measure indices

For the problem with a fuzzy failure state which commonly exists in degradation structures and systems, the fuzzy failure probability based importance measure indices can be used to measure the effect of the input variables on the fuzzy failure probability effectively. However, the computational cost is unaffordable for estimating the indices directly. For efficiently evaluating the fuzzy failure probability based importance measure indices, this paper proposed two numerical simulation methods, i.e., the direct Monte Carlo simulation method based on the Bayesian formula (B-DMCS) and the adaptive radial-based importance sampling method based on the Bayesian formula (B-ARBIS). The two proposed methods employ the Bayesian formula to eliminate the dependence of the computational cost on the dimensionality of the input variables. Compared with the B-DMCS method, the B-ARBIS method can enhance the computational efficiency significantly due to repeatedly utilizing the same group of samples of the input variables and the strategy to adaptively search the optimal hypersphere in the safety domain. After giving the principles and implementations of the two methods, three examples are employed to validate the effectiveness of the two proposed numerical simulation methods. The results of the examples demonstrate that the effectiveness of the two proposed methods is higher than the direct Monte Carlo method, and the B-ARBIS method can improve the efficiency obviously in contrast with the B-DMCS method.