摘要：The design of telecommunication network with capacity constraints of links, routers and ports of routers is considered in this paper. Specially, we limit each demand flow traversed through a pre-specified maximal number of links (called hops) under node failure scenarios in IP layer network. Such a design must be the most cost-effective and ensure that feasible flows continue to exist even when any relay node of the network fails. We propose a reliable mixed-integer programming (MIP) model with multi-scenario constraints to optimally design a minimum-cost survivable IP network that continues to support a good communication under any node failure scenario. Then we transform the MIP model into many single scenario models, that is, simplified MIPs, nonlinear programming (NLP) models and MIP models under Benders decomposition Then we transform the MIP model into many single scenario models, that is, simplified MIPs, nonlinear programming (NLP) models and MIP models under Benders decomposition. Three heuristic methods are proposed to solve these models including branch-and-bound algorithm, global algorithm for NLP, and heuristic algorithm based on benders decomposition. We mainly study the application of Benders decomposition method, where dual model and bounding procedures are given for each MIP model under Benders decomposition at each scenario. The results of our computational experiments validate the effectiveness of the proposed models and algorithms.

摘要：The design and performance evaluation of a sustained load creep testing machine was undertaken in this research. The design was motivated by the need to make locally available, a cost effective, technically efficient, and easily operated creep testing facility;for creep behaviour studies of materials. Design drawings and purchase of materials and components for the design were undertaken after thorough evaluation of the following design and materials selection criteria: design principle and theory, local availability of raw materials and components required for the design, material properties, cost of materials and design, ease of utilization and maintenance, and basis of testing and data capture. The machine casing and frame, heating chamber (consisting of the furnace and a dual specimen mounting stage), load lever and hanger system, and the electro-technical components;were fabricated and coupled following the produced design specifications. The machine was tested and its performance was assessed using its heating efficiency, repeatability and reproducibity of experimental test results, maintainability and cost-effectiveness as criteria. It was observed from repeat tests that the machine has the capacity of generating reliable data for computing creep strain-time results. The efficiency and temperature regulating capacity of the heating unit of the machine were also observed to be very satisfactory. The cost of the design was about 112,000 Naira ($700.00) which is cheaper in comparison to similar commercial creep testing machines from abroad. The machine was also found not to pose maintenance or repairs challenges.

摘要：我其实很少说impossible,几乎不太会有人从我的口中听到‘做不到’三个字。"奥美中国广告总裁薄荣蓉(Melinda Po)说。恰如她非常喜欢的保罗·柯艾略(Paulo Coelho)的一本书《牧羊少年的奇幻之旅》(The Alchemist)中所言,"There is only one thing that makes a dream impossible to achieve:the fear of failure.

摘要：Gravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape, mass and strength of the concrete. The purposes of dam construction may include navigation, flood damage reduction, hydroelectric power generation, fish and wildlife enhancement, water quality, water supply, and recreation. The design and evaluation of concrete gravity dam for earthquake loading must be based on appropriate criteria that reflect both the desired level of safety and the choice of the design and evaluation procedures. In Bangladesh, the entire country is divided into 3 seismic zones, depending upon the severity of the earthquake intensity. Thus, the main aim of this study is to design high concrete gravity dams based on the U.S.B.R. recommendations in seismic zone II of Bangladesh, for varying horizontal earthquake intensities from 0.10 g - 0.30 g with 0.05 g increment to take into account the uncertainty and severity of earthquake intensities and constant other design loads, and to analyze its stability and stress conditions using analytical 2D gravity method and finite element method. The results of the horizontal earthquake intensity perturbation suggest that the stabilizing moments are found to decrease significantly with the increment of horizontal earthquake intensity while dealing with the U.S.B.R. recommended initial dam section, indicating endanger to the dam stability, thus larger dam section is provided to increase the stabilizing moments and to make it safe against failure. The vertical, principal and shear stresses obtained using ANSYS 5.4 analyses are compared with those obtained using 2D gravity method and found less compares to 2D gravity method, except the principal stresses at the toe of the gravity dam for 0.10 g - 0.15 g. Although, it seems apparently that smaller dam section may be sufficient for stress analyses using ANSYS 5.4, it would not be possible to achieve the required factors of safety with smaller dam s

摘要：摘要：充血性心力衰竭（congestive heart failure，CHF）影响了相当一部分成年人，包括既往没有冠心病的人群。CHF的病因还不完全清楚，但是微血管病是可能的因素之一。目的：明确视网膜病作为全身微血管疾病的一个标志与CHF的关系。设计、地点、参试者：应用动脉粥样硬化危险社区研究资料库，在美国4个社区进行的长达7年的人群前瞻性队列研究。参试者（n=1l612，年龄49—73岁）于1993—1995年曾行视网膜照相。视网膜照相根据标准按照视网膜病（如微血管瘤、视网膜出血、软渗出）、动静脉压迹、局限性小动脉狭窄和普遍小动脉狭窄分级。主要结局指标：视网膜病与CHF的关系，后者经由住院及死亡记录证实。结果：7年累计CHF发生率为5．4％（492例）。与没有视网膜病的参试者比较，有视网膜病的参试者CHF的发生率较高（15．1比4．8，P〈0．001）。在校正年龄、性别、种族、已有冠心病、平均动脉压、糖尿病、血糖水平、胆固醇水平、吸烟、体重指数（BMI）和研究地点后，视网膜病的存在与CHF发病危险增加2倍相关（相对危险，1．96；95％可信区间，1．51—2．54）。在既往没有冠心病、糖尿病或高血压的参试者中，有视网膜病者发生CHF的危险增加3倍（相对危险，2．98；95％可信区间，1．50—2．92）。结论：视网膜病是CHF的独立危险预测因素，即使是在没有冠心病、糖尿病或高血压的人群。这提示，微血管疾病可能对普通人群心力衰竭的发病具有重要的作用。某些眼科检查发现无症状视网膜病的患者，可从进一步的CHF危险评估受益。

摘要：Under the new media,the dissemination and the influence of public events are often far more profound than traditional ***,it has gained a high degree of social *** take the apology mistakes in public events as an example,sort out the types and causes of the mistakes into a context,and propose some relevant strategies.

摘要：背景：肺动脉导管（pulmonary artery catheterization，PACs）已用于指导多种疾病的治疗。但是最近的研究认为，PACs可能会增加住院患者的死亡率。目的：确定使用PAC是否安全。是否会改善重症患者和心力衰竭复发住院患者的临床预后。设计、地点及参试者：充血性心力衰竭与肺动脉插管作用评估研究（Evaluation Study of Congestive Heart failure and Pulmonary Artery Catheterization Effectiveness，ESCAPE）是一项随机对照试验。试验于2000年1月18日至2003年11月17日在26家医院中的433例患者中进行。患者分为两组。一组根据临床诊断和PAC指导治疗，另一组仅根据临床诊断指导治疗。两组患者的治疗目标均为充血性心力衰竭临床症状缓解，PAC组的目标还包括肺毛细血管楔压降至15mmHg和右心房压力降至8mmHg。治疗药物无特殊规定，但是不鼓励使用影响心肌收缩力的药物。主要观测指标：主要终点为出院后6个月内的存活天数，次要终点包括运动耐力、生活质量、生化指标以及超声心动图改变。结果：疾病的严重程度通过以下指标加以评估：左心室平均射血分数，19％；收缩压，106mmHg；血钠浓度，137mEq／L；血尿素氮，35mg／dL（12．40mmHg）；血肌酐，1．5mg／dL（132．6μmol／L）。两组患者经治疗后，临床症状、颈静脉压和水肿均明显缓解。使用PAC对主要终点出院后6个月内存活天数（133天比135天；风险比[hazard ratio，HR]，1．00；95％可信区间[confidence interval，CI]，0．82～1．21；P=0．99）、死亡率（43例[10％]比38例[9％]；优势比[oddsratio，OR]，1．26；95％CI，0．78～2．03；P=0．35）以及住院天数（8．7天比8．3天；HR，1．04；95％CI，0．86～1．27；P=0．67）无明显影响。PAC组患者住院不良事件更为常见（47[21．9％]比25[11．5％]；P=0，04）。未见到与PAC使用相关的死亡事件，住院和30天总死亡率没有差异（10[4．7％]比11例[5。0％]；OR，0，97[95％CI。0．38—2．22]；P=0．97）。两组患者运动和生活质量均获改善，PAC组具改善更趋明显，这一趋势在随机后各时间点均达到显著水平。结论：住院期间对心力衰竭患者进行降低容量负荷的治疗（不论是否使用Pac）均能显著改善充盈压升高引起的临床症状和体征。在仔细进行临床评估的基础上加用PAC可增加预期不良事件的发生，但对总死亡率和住院率没有影响。将来的试验应该研究、验证特殊治疗策略的非介入评估方法。以便根据患者存活时间和生存质量评估结果来制定更好的治疗措施。