Improving Cost Estimates of Construction Projects Using Phased Cost Factors

Central to cost-based competition is the capability to accurately predict the cost of delivering a project. Most literature on cost estimation focuses on specific estimation methods as generic techniques and little attention has been paid to the unique requirements at each project stage. This note attempts to identify the critical factors for effective estimation at various stages of typical construction projects. Drawing from organization control theory and cost estimating literature, this note develops a theoretical framework that identifies the critical factors for effective cost estimation during each project phase of a conventional construction project. The underlying logic is that as a cost estimating effort progresses, both task programmability and output measurability improve. As a result, control effort will shift from input-oriented control to a combination of output and behavior control.     

试论普通高校成人高等教育的地位和现状

文章首先分析成人高等教育在构建终身教育体系中的地位和作用,指出成人高等教育是我国高等教育的重要组成部分,在实现大众化教育过程中起着重要且不可或缺的作用.然后,结合我国入世后全面参与全球化的大背景,在向市场经济转轨,经济和社会实现跨越式发展的关键时期,在普通高校不断扩招的形势下,论述我国成人高等教育的发展所面临的一系列挑战.     

预测油气田产量的β模型

通过对油气田产量变化规律进行系统研究，推导建立了预测油气田产量的β模型。该模型不但可以预测油气田产量、累积产量随生产时间的变化，而且可以预测可采储量、最高年产量及其发生的时间。实例检验该模型是可信的。     

微滤膜清洗的研究

用次氯酸钠溶液、氢氧化钠溶液和盐酸溶液对小型微滤膜进行化学清洗试验,比较试验结果认为,用次氯酸钠溶液对受污染的微滤膜清洗更为有效,从而为鄂尔多斯羊绒集团污水处理厂中的大型连续微滤化学清洗提供依据.     

通用串行总线(USB)数据传输模型

USB作为一种数据传输接口，了解它的通信传输机制是正确利用USB利用数据传输的基础，分层次结构对USB数据传输模型加以分析，可以使读者建立起USB体系结构、通信模型和总线事务的框架和概念，并最终对USB传输工作流程有一个清晰的认识。     

快速二阶BP网络及其在城市用水量预测中的应用

针对BP网络收敛速度慢，易导致局部极小值的缺点，提出一种快速二阶BP网络，并以城市年用水量预测为例，与BP网络对比，结果表明，该方法加快了收敛速度，提出了结果的准确度。     

Ion irradiation—induced structure damage to botanic samples using the ion transmission energy spectrum

1 INTRODUCTIONThe new aPplications of low energy heavy ion beam in irradi4ted botanical materialswere studied in recellt yeaxs. The beaminduced mutation effect on crop seeds has causedthe attention of physicist and biologists.[1l:] FOr examPle, 1ow energy ions can induceremarkable mutation to rice seeds.[3] There are many special phenomena when heavyions bombard botanic sW1e due to its special structure. Some studies showed that tllepenetration depths of some ions were far larger than t…     

框架剪力墙结构工程主体施工

要保证高层建筑的施工质量、技术要求、加快施工速度 ,关键是要解决好高层施工中的模板、钢筋、脚手架搭设以及轴线的竖向传递等几项技术 ,通过工程实践对这几项施工技术进行了总结 ,该技术既满足了施工高层建筑的要求 ,又取得了降低工程成本的效果。     

New balance ground relay for parallel four-circuit transmission lines

A 66-kV network generally is grounded through a neutral grounding resistor. In this network a single-phase ground-fault current is limited to as small as 100 to 400 A. There are parallel four-circuit transmission lines mounted on the same tower in the 66-kV network. In such transmission lines, the load and the fault currents could induce circulating current that flows through the lines. Since the circulating current has zero-phase-sequence and negative-phase-sequence components, it could cause unwanted operation of a balance ground relay using zero-phase-sequence current. However, it is difficult to compensate for the circulating current by the conventional vector compensation scheme. This paper presents a new balance ground relay to deal with the circulating current. In the relay from the ground-fault inception until first tripping, the difference current Δ3I_2d of negative-phase-sequence current 3I_2d of the differential current between two protected lines is used as an input current. The Δ3I_2d is the difference current of 3I_2d between, before and during faults. After the first tripping, the difference current of positive-phase-sequence load current and zero-phase-sequence current of the forementioned differential current are used as an input current. Consequently, a higher sensitivity of the ground-fault protection for these lines has been achieved. The correct operation of the new balance ground relay was confirmed when a single-phase-ground-fault occurred in the parallel four-circuit transmission lines, to which the relay is applied.     

Different susceptibility to phospholipase A2 treatment of the fluorescence intensity changes in the vicinity of Cys-964 and Lys-501 in the alpha-chain of probe-labeled Na+,K(+)-ATPase

Phospholipase A2 [EC 3.1.1.4] treatment of pig kidney Na+,K(+)-ATPase [EC 3.6.1.3] labeled with fluorescence probes at the alpha-chain reduced the extent of the fluorescence intensity change of an N-[p-(2-benzimidazolyl)phenyl]maleimide (BIPM) probe at Cys-964 to below one-third of the control level accompanying the accumulation of phosphoenzymes. However, it only induced a slight decrease in that of a fluorescence isothiocyanate (FITC) probe at Lys-501 with a large decrease in the rate of change. The addition of phosphatidylserine (PS) or phosphatidylinositol (PI) to the phospholipase-treated BIPM-FITC-labeled enzyme increased the rate of the FITC fluorescence change. Phospholipase treatment of the BIPM-enzyme greatly reduced the Na+,K(+)-ATPase activity. The addition of PS or PI to the treated enzyme induced reactivation. These data and others suggest that Cys-964 and Glu-953 (Rb+ protectable dicyclohexyl carbodiimide binding site) are located in the vicinity of the surface area of the enzyme where hydrocarbon chains of phospholipids are present, and conserved H-bonding amino acids, Thr-955 and Ser-962, are located rather near the center of a domain forming a cation binding route or cage with other hydrophobic transmembrane segments. These data may indicate that the interaction between the BIPM probe and the hydrocarbon chains of phospholipids changes in such a way as to sense the change in the binding state of various ligands accompanying the sequential appearance of reaction intermediates of the enzyme.