Decision model for allocating human resources in information system projects

Human resource allocation (HRA) can be viewed as core processes of the project management of information systems. Both in organizations, the business of which is to provide solutions for Information Systems, as in units of companies that work with Information Systems (IS), there are frequent demands for human resources to be allocated to IS projects. However, this is not a simple task and becomes more complex as the numbers of projects and professionals, including the range of expertise required, increase. This paper presents a methodology, based on dynamic programming, to assign human resources to software development projects. The methodology takes into account the complexity of each project and the existing capabilities of staff and the skills required for the project. A simulation is used to demonstrate the decision model.     

通过结构优化设计提高房屋抗震性能

在设计中进行结构优化是必须的,但不能简单地理解为仅仅是减少钢筋和混凝土的用量,应当从建筑方案设计阶段就开始结构方案的初选,通过多种方案的计算比较才能获得建筑、结构协调一致的最优方案,从而为业主提供最佳的产品。     

Seismic reliability of electric power networks: methodology and application

This paper proposes a model and implements a computational procedure to assess the reliability of electric power networks subjected to seismic load. A general electric network is first described and its functioning under ordinary conditions and under seismic action is analyzed. A reliability model to assemble small into larger components is proposed, which drastically simplifies the analysis. Power flow equations in the network are presented and modified to account for the current configuration of the network under seismic action. Seismic hazard is computed with the Cornell model. The whole procedure is applied to a real electric network and a simulation procedure is used to assess its reliability, measured via the probability distributions of suitable performance indexes.     

后张预应力混凝土结构抗震优化

跨度较大的梁由于弯矩较大,现阶段设计人员已普遍采用预应力混凝土,通过预应力的等效弯矩,部分减少各跨中、支座截面的拉应力,以达到同时满足抗裂和极限承载的要求,但如果设计施工不当,可能造成梁端弯矩远大于柱端,梁柱节点遭到削弱,以及柱抗震能力下降等不利于抗震的情况,本文主要针对这些问题从设计和施工两方面采取的优化措施进行论述。     

Seismic performances of dyke on liquefiable soils

Various field investigations of earthquake disaster cases have confirmed that earthquake-induced liquefaction is a main factor causing significant damage to dyke, research on seismic performances of dyke is thus of great importance. In this paper, seismic responses of dyke on liquefiable soils were investigated by means of dynamic centrifuge model tests and three-dimensional (3D) effective stress analysis method which is based on a multiple shear mechanism model and a liquefaction front. For the prototype scale centrifuge tests, sine wave input motions with peak accelerations 0.806 m/s², 1.790 m/s² and 3.133 m/s² of varied amplitudes were adopted to study the seismic performances of dyke on the saturated soil layer foundation with relative density of approximately 30%. Then, corresponding numerical simulations were conducted to investigate the distribution and variations of deformation, acceleration, excess pore-water pressure (EPWP), and behaviors of shear dilatancy in the dyke and the liquefiable soil foundation. Moreover, detailed discussions and comparisons between numerical simulations and centrifuge tests were also presented. It is concluded that the computed results have a good agreement with the measured results by centrifuge tests. The physical and numerical models both indicate that the dyke hosted on liquefiable soils subjected to earthquake motions has exhibited larger settlement and lateral spread: the stronger the motion is, the larger the dyke deformation is. Compared to soils in the deep ground under the dyke and the free field, the EPWP ratio is much smaller in the shallow liquefiable soil beneath the dyke in spite of large deformation produced. For the same overburden depth soil from free site and the liquefiable foundation beneath dyke, the characteristics of effective stress path and stress–strain relations are different. All these results may be of theoretical and practical significance for seismic design of the dyke on liquefiable soils.     

Seismic response of a continuous bridge with bearing protection devices

Unseating of bridges during earthquakes results from the failure of bearings and insufficient seat length. In case of elastomeric bearings, large deformations of the superstructure occur, under severe earthquake ground motions and additional protection measures are necessary. The combination of a displacement restraining device with the elastomeric bearing can prevent bearing failure. This paper evaluates the performance of four different types of protection devices to limit the displacement of the superstructure during earthquakes: (1) rigid stopper device, (2) yielding stopper device, (3) steel restrainer, and (4) superelastic shape memory alloy (SMA) restrainer. Analytical models for all the protection devices have been developed and seismic response of an existing bridge with elastomeric bearings and different protection devices has been evaluated for five strong ground motion records scaled in the frequency domain. The results show that all the protection devices have comparable performance in preventing the failure of bearing during an earthquake.     

Determination of optimal target reliabilities for design and upgrading of structures

A systematic approach is proposed for formulating risk-based cost-effective criteria for the design and upgrading of structures with special reference to earthquake protection. Target reliabilities (or acceptable risks) for damage control and life safety are determined on the basis of minimum expected life-cycle cost and from which risk-consistent criteria for design or upgrading are developed. The approach is illustrated for a specific class of reinforced concrete buildings in Mexico City.     

浅谈热工保护系统在新建机组中的可靠应用

主要介绍了在电建施工阶段调试运行期间针对如何提高热工保护系统的可靠性和稳定性提出的相应控制措施,为电建施工行业在新机组调试运行期间的生产管理和安全生产提供有益的帮助。     

南京新世纪中心顶部钢塔结构动力特性及地震响应分析

本文首先介绍了江苏省第一高楼南京新世纪中心顶部钢塔的三维模型的建立，然后通过模态分析计算了主体结构和顶部钢塔的动力特性，以及二者之间的相互影响。在此基础上采用振型分解反应谱法对钢塔在地震力作用下的响应进行了计算分析，并提出该钢塔鞭梢效应的放大系数。     

Seismic response of stainless steel braced frames

The present paper investigates the feasibility of the application of stainless steel (SS) in the seismic design of braced frames, either concentrically (CBFs) or eccentrically (EBFs) braced. A sample of regular multi-storey CBFs and EBFs was designed in compliance with modern seismic standards based on capacity-design rules. The results of pushover and inelastic response history analyses demonstrate that systems employing SSs exhibit enhanced plastic deformations and excellent energy absorbing capacity with respect to mild steel braced frames. The augmented strain hardening of SS, which is nearly twice that of carbon steels, is beneficial to prevent local buckling in steel members, especially those subjected to high axial compression. The performed analyses also demonstrate that in CBFs with SS braces and columns the increase in overstrength is about 40% with respect to the configuration in mild steel. For EBFs, the use of SS in the diagonals or in braces and links increases the global overstrength of the lateral resisting system by 20%. When the EBFs employ braces and columns in SS the increase can be as high as 50%.     

Seismic performance and collapse prevention of concrete-filled thin-walled steel tubular arches

The primary objective of this paper is to investigate the seismic behaviour of concrete-filled steel tubular (CFST) arches using incremental dynamic analysis (IDA). A nonlinear elastic–plastic finite element model is developed using OpenSees software and is verified with a shaking table test. Single-record IDA studies indicate that a CFST arch undergoes global dynamic instability when subjected to ground motions of increasing intensity levels. During this process, either dynamic elastic buckling or dynamic elastic–plastic buckling may occur. Dynamic strength, which is defined as the capacity for preventing global dynamic instabilities of CFST arches, is determined with a series of multi-record IDA calculations. A lower bound equation that takes into account the effect of slenderness ratio, axial compression ratio, and included angle is proposed for the prediction of the dynamic strength of CFST arches.     

建筑结构轻钢屋面板抗震试验和加固

对9个轻钢屋面板试件进行试验研究,以评估其抗震性能。根据当前的隔板设计方法,隔板能够提高承受动力荷载的剪切强度,而不是剪切刚度。此外,随着振幅增大,剪切刚度降低。使用较厚的面板或面板的安装方向与荷载方向平行时,隔板延性将降低。大多数损坏的隔板维修后可达到其初始强度,抗震加固措施能够有效增加电弧点焊/按钮冲隔板的剪切强度和刚度。     

Wastewater reuse potential analysis: implications for China's water resources management

It has been recognized that wastewater reuse or reclamation serves as an efficient and valuable way to cope with the scarcity of water resources and severity of water pollution. This paper presents the systematic framework of wastewater reuse potential estimation. Based on the regional disparities in China, a linear programming optimization model is developed to explore the potential wastewater reuse quantities, under physical and economic constraints. Sensitivity analysis and Robust Counterpart (RC) optimization are performed to discuss the influences of key parameters and the reuse quantity's decision making under uncertainty. Based on the model, effectiveness of different policy scenarios of water price changes are simulated and evaluated, providing information regarding China's water and wastewater management.     

高墩大跨度连续刚构桥的抗震分析

本文以一座高墩大跨度连续刚构桥的设计实例为背景,建立起动力分析模型,对桥梁结构的动力特性进行了计算分析;并采用线性时程方法,输入实际地震波激励,对该结构在地震作用下的时程响应进行了分析研究,探明了高墩连续刚构桥在纵向、横向和竖向多维地震动作用下的响应特点,为该类结构的抗震设计提供参考。     

罕遇地震作用下高架桥抗震性能评估与加固

为了评估罕遇地震作用下高架桥的抗震性能,提出了一套抗震性能评估流程并对一座在役高架桥进行评估.首先建立了高架桥非线性动力时程分析模型;然后进行了模态分析,在综合考虑了有效质量系数和振型图后,选取了用于计算Rayleigh系数的参考振型;最后对动力时程分析结果中各墩的弯曲变形能力和抗剪强度进行评估,并根据评估结果提出了加...     

Seismic behaviour of reinforced embankments in dynamic centrifuge model tests

A series of dynamic centrifuge model tests was conducted to investigate the effects of reinforcement on the seismic behaviour of hillside embankments consisting of sandy soils and resting on stiff base slopes. In total, three types of seismic reinforcements, namely, large-scale gabions, drainage-reinforcing piles, and ground anchors with pressure plates, were employed in the tests. The test results showed that: (1) the seismic performance of both lower and higher embankments was remarkably improved by installing large-scale gabions at the toe as they restrained the completion of the formation of sliding planes; (2) the installation of drainage-reinforcing piles at the embankment toe was rather effective in reducing the overall earthquake-induced deformation due to their high permeability and restraint effect against sliding displacement at the reinforced region; and (3) the embankments improved by ground anchors with pressure plates were not vulnerable to earthquake-induced damage due to their constraint effects even under high water table conditions. The improvement effects by the above-mentioned three types of reinforcements were presented by evaluating the global safety factors based on the results of a series of triaxial compression tests.     

Seismic displacements of landfills and deformation of geosynthetics due to base sliding

Seismic design of waste landfills has been a subject of intense research over the past two decades, primarily due to the severe environmental impact of a potential failure. The majority of the related studies have been focused on the stability assessment of landfills utilizing permanent deformation methods. However, previous investigations have not fully addressed the impact of the composite liner system on the seismic performance of the geostructure, mainly expressed as potential sliding development, which is greatly affected by the geometry and the resulting initial static stress state of the landfill. Therefore, the aforementioned issues are investigated via a detailed parametric study, where the dynamic behaviour of the composite liner system is examined both analytically and numerically. The conducted coupled analyses indicated that the most significant parameters of the complex dynamic response of waste landfills can be reduced in two ratios that comprise functions of the main characteristics of the geostructure and of the excitation. Moreover, two distinct failure patterns have been identified with respect to the characteristics of the distribution of the permanent displacements along the interface and the axial deformation along the geosynthetic. The occurrence conditions of these failure patterns can be determined in terms of the two abovementioned ratios as verified by the analytical results of the critical acceleration of a simple SDOF system.     

半地下贮液池结构抗震分析方法的修正系数研究

半地下贮液池作为一种特殊的地下结构,在地震作用下可能发生的震害也较为多样.该半地下贮液池结构复杂,有限元模型单元和节点数量多,难以采用时程分析法进行计算;拟静力法计算简单,但不能得出结构在动态的地震波下的最大响应,因此提出一个修正系数用以拟静力法与时程分析法结果的互相转换.本文在建立半地下贮液池实际有限元模型的基础上建...     

用持续时间分析法对钢储液箱进行抗震分析

持续时间(ET)法是基于时程分析法,对结构进行高强度动态激励从而进行抗震评估的一种方法。运用此方法对钢储液箱进行了分析。对采用ET法对钢储液箱的抗震评估进行了研究。该方法已经在3个不同尺寸、具有特定支座的钢储液箱的有限元非线性分析中得到了应用,并将分析结果与常规设计规程进行了对比。分析结果表明,用该方法评估钢储液箱的地震反应的准确性和各种复杂条件下加强钢储液箱设计方法的适用性。阐述了利用地面运动对底部嵌固和非嵌固的钢储液箱的地震反应的对比研究。还讨论了该方法的优势和不足之处。     

Seismic safety of lifelines—an optimum design method

Lifeline systems are vulnerable to two types of hazards arising from potential earthquake sources. These are the hazard of a fault-rupture strike on elements of a lifeline system and the hazard of overstress induced in different elements of the system because of the ground vibration. An optimum design method is presented in this paper for the design of a lifeline system for a maximum accepted probability of failure because of any of the two modes of failure. The method may be used to determine an optimum path between a number of fixed points which represent supply or demand stations in the system.