基于网络特性分析的时间费用权衡问题研究

发布时间：2019-06-09 16:08

【摘要】：随着经济的发展,项目管理在社会发展中的地位越来越重要,项目管理的三大目标是时间、成本和质量管理,时间、成本管理是紧密联系、相互制约的,对时间和费用进行综合优化的时间-费用权衡问题是项目管理中一个非常重要的方面,在实际中有着重要意义。求解时间-费用权衡问题的方法很多,本论文主要研究如何充分结合关键路线法(Critical Path Method,简称CPM)网络计划的特点,特别是机动时间的特性规律,实现对求解时间-费用权衡问题的有效求解。对时间-费用权衡问题的研究始于上世纪六十年代初,并且所涉及的范围在随后的几十年中大为扩展,但在问题的解决上却一直未取得突破性进展,最主要的瓶颈就是解决该类问题时所遇到的高复杂度和大计算量。为了消除该瓶颈,本论文采用新的思路,通过简化问题所涉及的计算对象来降低求解时所面临的高复杂度和大计算量,而不是去设计或改进解决问题的算法。本论文用关键路线法网络计划技术作为工具,在机动时间特性研究的基础上,把超大型工序网络化简为等效的简单网络,从而使不可计算的问题转化为可计算的问题,使很复杂的问题转化为比较简单的问题,尤其是利用化简后的网络求解时间-费用权衡问题,无论使用任何一种算法其计算量都会大大减小。因此,本论文的研究不仅具有重要的理论意义,而且具有极大的实用价值。除了等效化简,本文进一步采用了另外两个措施来简化时间-费用权衡问题的求解过程,一个是确定每部压缩的最大有效压缩量,另一个是修正各工序的工期压缩量。确定每部压缩的最大有效压缩量,目的是为了用最少的压缩步骤实现对总工期最有效的压缩,原理为,在一步压缩中,压缩网络中的关键路线,当网络中出现新的关键路线时,停止压缩,此时压缩的量就是该步压缩的最大有效压缩量。修正各工序的工期压缩量,主要是根据全局优化的一个基本原理,即,步步最优不等于全局最优。即使每部压缩都用最低的压缩费用,并且压缩量也都是最大有效压缩量,但是最终的压缩效果仍然可能不是最优的,甚至可能是最差的,因此,为了实现全局最优的压缩效果,需要对各工序的压缩量进行修正,使其成为真正最优的压缩量。修正压缩量的主要原理是,如果某关键工序的压缩量最优,那么它被压缩后必定仍是关键工序；如果它被压缩后成为非关键工序,则此时的压缩量必定不是最优的,需要进行修正,也就是将其工期延长,直到该工序重新成为关键工序为止。本论文研究的主要内容如下： 1.对关键路线法进行了拓展。传统关键路线法可用于确定各工序时间的可取范围,各工序的时间参数通常自身没有严格限制,而是受总工期和其它工序的限制,并且用关键路线法表示出来。但是如果某些工序的时间参数自身带有一定限制,如只能在某时刻开始,或某时刻结束,那么在它的影响下,其它工序的时间参数会有什么样的变化,运用传统关键路线法无法得知。因此,本文对这类情况进行了分析,提出了拓展的关键路线法,用于求解在该情况下各工序时间参数的取值范围。 2.运用CPM网络计划并结合网络流算法是当前使用最广泛的求解时间-费用权衡问题的方法,具有一定的优越性,但是也具有较明显的缺点。本文针对其优点和缺点,指出了要想提高该方法的求解效果和准确性,应对哪些方面进行改进,并且提出了对这些方面进行改进的原理。 3.提出直接法的改进方法来求解时间-费用权衡问题。根据直接法的改进原理,提出了改进措施,例如,提出了新的等效化简时间-费用权衡问题的方法,提出了确定工期压缩过程中每步压缩的最大有效压缩量,以及工期压缩量的合理修正等,并利用这些措施提出了直接法的两种改进方法。 4.提出求解连续型时间-费用权衡问题的新算法。借鉴直接法的改进原理和思路,从新的角度对时间-费用权衡问题进行分析,给出了新的求解思路和方法。
[Abstract]:With the development of economy, the position of project management in social development is becoming more and more important, and the three main objectives of project management are time, cost and quality management, time and cost management are closely related and mutually restricted. The time-cost trade-off problem of comprehensive optimization of time and cost is a very important aspect in project management, which is of great significance in practice. In order to solve the problem of time-cost trade-off, this paper mainly studies how to fully integrate the characteristics of the Critical Path Method (CPM) network plan, especially the characteristics of the maneuver time, and realize the effective solution to the problem of time-cost trade-off. The study of time-to-cost trade-off began in the early 1960s and the scope involved was greatly expanded in the following decades, but there has been no breakthrough in the solution of the problem, The most important bottleneck is to solve the high complexity and the large amount of computation encountered in this type of problem. In order to eliminate the bottleneck, this paper adopts a new approach to reduce the computational objects involved in solving the problem to reduce the high complexity and the large amount of calculation, and not to design or improve the solution to the problem. This paper uses the key route method network planning technology as a tool, and on the basis of the study of the mobile time characteristic, the network of the super-large process is simplified into the equivalent simple network, so that the non-computable problem can be converted into a computable question. The problem is that the complex problem can be transformed into a relatively simple problem, especially using the network to solve the time-cost trade-off problem after the simplification, and the calculation amount of any algorithm can be greatly reduced Therefore, the research of this paper not only has important theoretical significance, but also has great practical price. In addition to the equivalent simplification, the paper further adopts two other measures to simplify the time-cost trade-off process, one is to determine the maximum effective compression amount of each compression, and the other is to correct the construction period of each process. The amount of compression is determined. The maximum effective amount of compression for each compression is determined to achieve the most efficient compression of the total duration in order to achieve the most efficient compression of the total duration with the least compression step, in principle, in one-step compression, the critical route in the compressed network, when a new critical route appears in the network, stops The amount of compression is the maximum effect of the step compression at this time. The amount of compression used to correct the construction period of each process is mainly based on a basic principle of global optimization, that is, the step of step is not equal to full The Bureau is optimal. Even if each compression is at the lowest compression cost, and the amount of compression is also the maximum effective compression, the final compression effect may not be optimal or even worse, and therefore, in order to achieve a global optimum pressure, It is necessary to correct the compression amount of each process to make it truly optimal. The main principle of correcting the amount of compression is that if the amount of compression of a critical process is optimal, it must still be a critical step after it is compressed; if it is compressed to become a non-critical step, the amount of compression at this time must not be optimal, and it is necessary to make a correction, that is, to work it The period is extended until the process is re-established as a key. The subject of this paper. The content is as follows:1. For critical paths the line method is extended. The traditional key route method can be used to determine the desirable range of each process time. The time parameters of each process are not strictly limited by themselves, but are limited by the total construction period and other processes, and are critical The route method is shown. However, if the time parameters of certain processes have a certain limit, such as only at a certain moment, or at some point of time, the time parameters of the other processes will change in the influence of it, and the use of the traditional key The route method can't be known. Therefore, this paper makes an analysis of this kind of situation, and puts forward the key route method of the expansion, which is used to solve the process time in this situation. 2. Using the CPM network plan and combining the network flow algorithm is the most widely used method to solve the time-cost trade-off problem, but it has some advantages, but In this paper, the advantages and disadvantages of this method are pointed out in this paper. In this paper, it is pointed out that the solution effect and the accuracy of the method are to be improved, and the improvement is made. The principle of improvement is presented in this paper.3. An improved method of direct method is proposed. In order to solve the problem of time-cost trade-off, according to the improvement of the direct method, the improvement measures are put forward, for example, a new method of equivalent simplification time-cost trade-off is put forward, and the maximum effective amount of compression for each step in the construction period compression is proposed. The reasonable correction of the amount of time limit of the construction period, etc., and make use of these measures Two methods of improving the direct method are presented.4. The solution of continuous type is proposed. The new algorithm of time-cost trade-off problem. The time-cost trade-off problem is analyzed from a new angle based on the improvement principle and the thought of the direct method.
【学位授予单位】：华北电力大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TP301.6

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