赢得值管理在工程总承包项目中的应用

本文以工程总承包工程项目中的赢得值管理为研究对象,目前的工程项目对进度、造价控制提出了更高的要求,采用科学的赢得值管理,可以将项目的进度与成本有机地结合起来,对开展总承包项目具有一定的应用意义。     

Modeling cascade dynamics of railway networks under inclement weather

Understanding the cascade dynamics of delay propagation under inclement weather is crucial to proactive railway management. In this paper, we proposed a Switching Max-Plus System (SMPS) to model the delay propagation on railway networks, which extends the conventional MPS by incorporating multiple system matrices to capture the dynamic impacts of inclement weather. An algorithm based on the All-Paired Critical-Path (APCP) graph was developed to solve the SMPS, which calculates secondary delays without backtracking the precedent events. The proposed model and its solution algorithm were validated using discrete-time simulations on both artificial and empirical networks. The robustness of railway services was also analyzed using the concepts of vulnerability and diffusivity.     

CPR1000项目核岛阀门采购进度控制分析

核岛阀门是核电厂重要的系统组成设备,涉及上下游的工作量大而广,其供应及时性对项目进度的有序推进尤为重要,本文针对岭澳二期、红沿河项目一期工程核岛阀门的供应状况进行研究,提出了针对性的进度控制优化策略。     

ARBITRAGE BOUNDS FOR PRICES OF WEIGHTED VARIANCE SWAPS

We develop a theory of robust pricing and hedging of a weighted variance swap given market prices for a finite number of co‐maturing put options. We assume the put option prices do not admit arbitrage and deduce no‐arbitrage bounds on the weighted variance swap along with super‐ and sub‐replicating strategies that enforce them. We find that market quotes for variance swaps are surprisingly close to the model‐free lower bounds we determine. We solve the problem by transforming it into an analogous question for a European option with a convex payoff. The lower bound becomes a problem in semi‐infinite linear programming which we solve in detail. The upper bound is explicit. We work in a model‐independent and probability‐free setup. In particular, we use and extend Föllmer's pathwise stochastic calculus. Appropriate notions of arbitrage and admissibility are introduced. This allows us to establish the usual hedging relation between the variance swap and the “log contract” and similar connections for weighted variance swaps. Our results take the form of a FTAP: we show that the absence of (weak) arbitrage is equivalent to the existence of a classical model which reproduces the observed prices via risk‐neutral expectations of discounted payoffs.     

一种基于有限元计算的半挂车强度分析

用有限元计算方法对某型半挂车车架的强度进行了分析计算。通过有限元仿真计算,提出在进行局部加强的同时,采用细而密的横梁结构的优化方案,解决了原来结构的应力集中现象,确保半挂车的结构强度。     

Grey Critical Chain project scheduling technique and its application

Based on the idea of Grey System and interval number coefficient notation, a Grey Critical Chain scheduling approach is studied. According to Grey system Theory, the time of project or task completion can be considered as the object that extension is definite but intension is uncertain, which is coincident with the character of the project management. The Grey Critical Chain Scheduling Technique mainly aims at the single project time management, but the management idea can also be applied to the other knowledge areas of the project management. In this technique, we improve the selection method of the buffer time in the Critical Chain, in order to obtain reasonable Feeding Buffer time and Project Buffer time. In this paper, we will use an example to discuss the Grey Critical Chain Scheduling Technique, compare Grey Critical Chain with Program Evaluation and Review Technique, Critical Chain and Fuzzy Critical Chain, and analyze the advantages, disadvantages and applicable scope of their own.     

项目进度绩效指标的改进及其动态性预测

传统的挣值方法中,进度指标的预测多表现单期、静态的特性,存在严重的局限性。为了改进和完善挣值管理方法中进度指标体系,在考虑时间序列的基础上,将统计方法引入挣值管理进度指标体系中,用更加科学的方法对项目进度指标进行描述,并在此基础上基于贝叶斯推断方法,加入专家意见,从统计学的角度提出了进度绩效指数的动态预测模型,因而,可以为项目管理者提供科学的据侧依据。     

大型冶金建设工程项目进度控制研究

研究大型冶金建设工程项目进度控制对提高冶金建设质量水平、控制建设投资具有重要的现实意义。     

使用FOB术语的五个问题分析

FOB术语是现今使用最多的贸易术语之一，本文详细分析了使用FOB术语需要特别注意的五个问题：船货衔接问题、装船和装船费用问题、卖方代买方租船订舱问题、风险转移问题和单证问题。     

Estimating persistent and transient technical efficiency and their determinants in the presence of heterogeneity and endogeneity

We develop an estimation procedure that generates consistent estimates of the technology parameters, long-run (persistent) and short-run (transient) technical inefficiencies and the marginal effects of their determinants for the stochastic frontier model developed by Colombi et al. (2014, Journal of Productivity Analysis 42, 123) and Kumbhakar et al. (2014, Journal of Productivity Analysis 41, 321). Our approach accounts for three sources of potential endogeneity: (i) unobserved heterogeneity; (ii) simultaneity of input use with both types of technical efficiency; (iii) potential correlation of the noise term with the regressors. Using this approach we examine the effect of direct payments and farm size on the persistent and transient technical efficiency of French crop farms before and after the European Union's Common Agricultural Policy decoupling reform of 2003. Our results show that subsidy payments per hectare of utilised agricultural land had a significant positive effect on persistent technical efficiency and a significant negative effect on transient technical efficiency during the period before decoupling. For the period after the reform, the effect of subsidies is found to be significantly negative for persistent technical efficiency and insignificant for transient technical efficiency. The overall effect of subsidies on technical efficiency is found to be negative in both periods, albeit substantially lower in the period after decoupling. The effect of farm size on technical efficiency is found to be significant only for the period prior to the reform: it reduced persistent technical inefficiency but increased transient technical inefficiency during that period.