软件开发中的风险评估及其实践

在软件项目的开发过程中,准确地识别项目中存在的风险、对风险加以分析并采取有效的预防措施是保证项目成功的关键因素之一。风险评估是软件开发风险管理的重要组成部分,目前已经发展成为软件项目开发与控制的常用管理方法。文章叙述了Boehm关于风险评估的经典理论、SEI基于问卷调查的风险评估法、基于成本估算的风险评估法以及该领域的其它最新研究进展。最后对软件开发风险评估方法的发展方向提出了自己的观点。     

稳压器卸压阀卸压效果研究

基于国际上模拟严重事故瞬态过程最详细的机理性程序SCDAP/RELAP5/MOD3.1,主要分析研究了核电站未紧急停堆的预期瞬变(ATWS)初因(失去主给水、失去厂外电和控制棒失控提升)叠加辅助给水失效导致的堆芯熔化严重事故进程,并验证阻止ATWS导致堆芯熔化进程的一次侧卸压缓解措施的充分性和有效性.计算分析结果显示,一列稳压器卸压阀不足以充分降低一回路压力,压力仍然停留在10MPa以上,存在很大高压熔堆的风险.增加一列卸压阀可把一回路压力降低到3MPa左右,安注系统得以投入,及时有效地阻止堆芯熔化进程,降低了高压熔堆风险.分析结果还显示高压安注系统的投入对一回路卸压具有重要影响.     

福州温泉生态城布局方案的情景分析法初探

城市用地布局总体框架由用地评价、情景归纳、情景模拟三个步骤组成。（1）进行用地适宜性评价;（2）分析影响土地使用规划的关键因素及其驱动力,在此基础上根据驱动力的状态分类归纳出若干情景方案;（3）进行情景模拟,在地理信息系统的支持下得到不同情景方案。在不同的发展阶段,模拟城市不同的发展情况,并提出响应各个情景的规划方案。该论文结合福州温泉生态城的实例讨论了这一方法的工作流程以及相应的技术支持。旨在探索一种实用的基于GIS的城市用地布局情景模拟与方案评价方法,为相关的研究提供一定的借鉴意义。     

基于FIR模型的多径抑制方法研究

多径效应是卫星导航系统的主要误差源之一。在现有研究中,基于最大似然估计准则的方法被认为是最佳的多径抑制技术,但是当存在多路信号且路径数量未知时,其计算尤为复杂。本文提出了一种基于FIR模型的多径抑制方法,利用基准相关函数和最小均方误差准则对接收信号进行参数估计和多径信号对消。该方法具有实现简单,易于实时信号处理,计算量与多径路数无关等优点。仿真结果表明,其性能略优于基于最大似然估计准则的MEDLL（Multipath Estimating Delay Lock Loop）技术。      

减缓·适应——应对气候变化的若干规划议题思考

通过对气候变化与城市规划关系的辨析,阐述了应对气候变化的规划内涵,构建了应对气候变化的规划研究框架。从能源利用、交通与土地使用、建筑设计与管理、水资源管理、固废处理、旧材料利用等方面提出了减缓气候变化的若干规划议题;从温度变化、海平面上升、降雨模式变化、热带风暴等方面提出了适应气候变化的若干规划议题。提出将应对气候变化规划与法定规划体系有机整合,是当前城市规划行业急需解决的问题。     

从Scenarios到状态图的算法分析*

采用Scenarios进行需求建模能够反映从用户角度观察到的系统的行为,状态图是系统行为的精确描述。从Scenario到状态图的自动转换是指软件开发过程中从UML需求模型自动生成行为模型的过程,其研究对于细化系统行为,保持开发过程中模型间的一致性有重要意义。对其研究现状及进展进行了介绍,并对现有算法进行了总结和分类,进一步指出这些算法的不足和今后需要改进的方向。     

GIS和RS技术在城市防震减灾中的应用研究

结合福州市建筑物抗震性能普查及地理信息系统建设项目,阐述了地理信息系统（GIS）和遥感（RS）技术在城市防震减灾中的应用。其中重点讲述了如何应用G1S和RS技术进行建筑物抗震性能资料的快速采集以及普查成果数据在辅助政府决策方面的应用,希望能为国内其他城市的防震减灾工作提供参考和借鉴。     

Carbon profiles of remote Australian Indigenous communities: A base for opportunities

A decision-making model was constructed to assist remote Australian Indigenous communities select appropriate climate change mitigation programs. The Resilient Community and Livelihood Asset Integration Model (ReCLAIM) comprises six steps that focus on community assets and aspirations. The second of these steps is to determine the baseline carbon profiles of communities based on six sources of carbon emissions: materials, construction processes, stationary energy, transport, water systems and waste. The methodology employed an annualised lifecycle analysis of housing materials and construction, and an annual inventory of other emission sources. Profiles were calculated for two remote communities and compared to the Australian average and also average electricity consumption by remote communities in the Northern Territory.The results, expressed in tonnes of carbon dioxide equivalent (tCO₂-e), showed that average household carbon profiles of the two communities (6.3 and 4.1 tCO₂-e/capita/yr) were generally lower than the Australian average (7.3 tCO₂-e/capita/yr). The stationary energy results revealed that infrastructure and building design could raise fuel consumption and costs, and therefore carbon emissions, despite modest lifestyles. The carbon emission categories differed between the two communities highlighting the need for an individualised approach to understanding the drivers of carbon emissions and mitigation responses.     

A study of barrier walls for mitigation of unintended releases of hydrogen

Hydrogen jet flames resulting from ignition of unintended releases can be extensive in length and pose significant radiation and impingement hazards. Depending on the leak diameter and source pressure, the resulting consequence distances can be unacceptably large. One possible mitigation strategy to reduce exposure to jet flames is to incorporate barriers around hydrogen storage and delivery equipment. An experimental and modeling program has been performed at Sandia National Laboratories to better characterize the effectiveness of barrier walls to reduce hazards. This paper describes the experimental and modeling program and presents results obtained for various barrier configurations. The experimental measurements include flame deflection using standard and infrared video and high-speed movies (500 fps) to study initial flame propagation from the ignition source. Measurements of the ignition overpressure, wall deflection, radiative heat flux, and wall and gas temperature were also made at strategic locations. The modeling effort includes three-dimensional calculations of jet flame deflection by the barriers, computations of the thermal radiation field around barriers, predicted overpressure from ignition, and the computation of the concentration field from deflected unignited hydrogen releases. The various barrier designs are evaluated in terms of their mitigation effectiveness for the associated hazards present. The results show that barrier walls are effective at deflecting jet flames in a desired direction and can help attenuate the effects of ignition overpressure and flame radiative heat flux.     

Study of acrylamide mitigation in model system: Effect of pure phenolic compounds

Many natural antioxidant extracts were reported to potentially reduce the acrylamide formation during Maillard reaction. In this work, the effect of pure antioxidant molecules on acrylamide net amount was investigated in an equimolar asparagine–glucose system (10 mM) during heating (200 °C). All experimentations were performed in the newly designed test cell. Cinnamic acid and six phenolic compounds (gallic, ferulic, coumaric, caffeic acids, catechin, and epicatechin), displaying different antioxidant capacity, were added at 5 mM to the model system. The results indicated no reduction effect of the tested compounds on acrylamide net amount. Moreover, in the case of ferulic acid a slight but significant promoting effect was observed. An increase of antioxidant activity was also noticed during heating of model solution spiked with caffeic acid but the acrylamide level was not affected.