Value stream mapping in project management: A case study

This article describes the application of value stream mapping to analyze and redesign the way of managing the materials procurement stage of a project. A framework based on integrated definition (IDEF) methodology, the stream analysis approach, activity‐based costing, and discrete event simulation is presented. The stream analysis approach is used to analyze, diagnose, and manage process changes represented using an IDEF model. A dynamic simulation is used to evaluate the impact of the changes considered, to support the analysis of the process, and to model the performance of the proposed process. The overall methodology is demonstrated by applying it to a company whose core business is the design and construction of offshore oil rigs. The company specializes in engineering, procurement, and construction projects and has an annual portfolio of about six projects. Many of these projects have common features in terms of design and components, and they are all also characterized by a short “time to delivery.” For this reason, this study was aimed at assessing the possible effects that the application of new materials management policies could have on reducing both project completion time and the resources required.     

The co-evolution of third stream activities in UK higher education

This paper explores the co-evolution of third stream activities in UK higher education from 1970 to 2008. Drawing on interviews and archival analysis it identifies four distinct periods through which third stream activities have co-evolved. The research suggests that the co-evolution of the third stream mission in universities is inextricably linked to the emerging requirement for universities to demonstrate they have a purpose in society. It concludes that the rise of third stream activities has presented both universities and government with a means of doing this.     

《情歌》不见情 只有颓废人——《情歌》的主题分析

《J·阿尔弗雷德·普鲁弗洛克的情歌》的主题可划分为表层主题和深层主题。其表层主题是主人公的爱情之歌,但是爱情悲歌;其深层主题是反映了19世纪初西方社会的空虚和人的精神危机。     

高维数据流子空间聚类发现及维护算法

近年来由于数据流应用的大量涌现,基于数据流模型的数据挖掘算法研究已成为重要的应用前沿课题.提出一种基于Hoeffding界的高维数据流的子空间聚类发现及维护算法--SHStream.算法将数据流分段（分段长度由Hoeffding界确定）,在数据分段上进行子空间聚类,通过迭代逐步得到满足聚类精度要求的聚类结果,同时针对数据流的动态性,算法对聚类结果进行调整和维护.算法可以有效地处理高雏数据流和对任意形状分布数据的聚类问题.基于真实数据集与仿真数据集的实验表明,算法具有良好的适用性和有效性.     

醋酸乙烯及下游产品的供需现状

文章介绍了醋酸乙烯国内外生产现状及下游产品的消费结构和我国醋酸乙烯主要下游产品的供需动向。     

3G手机密码服务中间件平台技术研究

密码服务中间件平台是保障3G手机终端安全的重要技术手段,具有较好的市场前景。本文对3G安全手机平台以及密码服务中间件平台进行研究,主要涉及安全手机平台、密码中间件两大部分。密码服务中间件平台是实现3G安全手机平台的核心部分,集成密码运算和安全存储能力,目的是直接供上层应用调用,提供方便易懂的密码应用接口,保障3G手机终端应用安全。     

Cash Stream Valuation In the Face of Transaction Costs and Taxes

The usual notion of every future cash stream having a net present value determined from a single term structure breaks down when transaction costs are taken into account, especially the sizable costs associated with short-borrowing. the difficulties are compounded by taxes, which can lead to paradoxes of disequilibrium if elementary NPV is assumed to be a rational basis for decision making. This paper systematically develops a theory of valuation which overcomes these shortcomings by accepting the multiplicity of no-arbitrage term structures that may be present for each tax class of investors, and uses the entire set of them to impute both a "long price" and a "short price" for every cash stream, regardless of the sign of the future payments. the valuation operators giving these prices are nonlinear but readily calculated from linear programming formulas.     

Arbitrage and Growth Rate for Riskless Investments in a Stationary Economy

A sequential investment is a vector of payments over time, ( a ₀, a ₁, ... , a_n ), where a payment is made to or by the investor according as a_i is positive or negative. Given a collection of such investments it may be possible to assemble a portfolio from which an investor can get "something for nothing," meaning that without investing any money of his own he can receive a positive return after some finite number of time periods. Cantor and Lipmann (1995) have given a simple necessary and sufficient condition for a set of investments to have this property. We present a short proof of this result. If arbitrage is not possible, our result leads to a simple derivation of the expression for the long–run growth rate of the set of investments in terms of its "internal rate of return."     

乙酸乙酯装置精馏系统的工艺优化

针对乙醛缩合法制乙酸乙酯的装置精馏系统中出现的因反应液中乙醛含量低而影响乙醛回收塔操作,以及因反应液中催化剂破坏液加入量不易控制而导致乙醇回收塔操作不稳定等问题,采取了暂时放弃乙醛回收,将乙醛回收塔顶液作为破坏液使用以稳定精馏系统操作等措施,确保产出合格乙酸乙酯成品。在此基础上,采取了从乙醛回收塔的塔顶回收乙醛,将侧线出料用作破坏液;使成品塔塔顶液全部回流,从侧线采出成品乙酸乙酯,加大塔釜液排放量并对其进行回收处理等一系列工艺优化措施,解决了因放弃乙醛回收而造成的成品乙酸乙酯质量下降和乙醛单耗上升等问题。     

并行环境下Java哈希机制的对比及重构

针对并行环境下出现的非线程安全问题,以哈希机制的Hashtable和ConcurrentHashMap的线程安全问题为切入点,设计了可改变线程总数和读写线程数的测试程序,分析了线程安全的ConcurrentHashMap和Hashtable的性能差异。根据性能差异,设计了从Hashtable到ConcurrentHashMap的程序自动重构插件,进而在Hashtable封装数据的情况下,通过对比传统多线程处理方式和Java8中的并行流处理方式的性能差异,分析了流处理方式相对普通多线程处理方式的高效性。对比结果显示,ConcurrentHashMap在并行程序中的性能要优于Hashtable。研究结果为多线程程序开发提出了解决非线程安全提供了较为可行的新思路,对于并行编程具有借鉴意义。