电子干扰效果与效能评估的研究

在研究现有电子干扰效果与评估的基础上,提出与现代电子战相适应的新型干扰效果和评估技术,定义新型的电子干扰效果评估因子和效能评估因子的概念与表示方法。     

贮存系统的联合维修策略

为了保证贮存系统的可用性,需要对其故障与否进行检测,针对该问题提出了包含定期检查和预先更换的维修策略。为了协调部件更换和备件供应,联合考虑了连续检查的（0,1）订货策略,所以联合维修策略包括维修策略和备件供应策略。基于联合策略建立了一个规划模型,在满足可用度约束条件下最小化平均总费用。基于更新过程,推导了贮存系统服从一般寿命分布的性能指标。以威布尔寿命分布为例,结果表明联合策略比独立策略更有效。     

用心守望这片蔚蓝——就尽快淘汰单壳油轮专访中国海事局常务副局长刘功臣

2008年的“两会”期间,全国政协委员、中国海事局常务副局长刘功臣向大会提交了《关于加强溢油应急体系建设的建议》,以2007年底发生在韩国海域的“Hebei Spirit”轮污染事故为警戒,痛陈溢油事故造成海洋污染的重大危害,呼吁加快我国溢油应急力量建设,加快淘汰单壳油轮。     

钙钛矿型La（0.3）Ca（0.7）FeO3的制备及其电化学性能

采用甘氨酸-硝酸盐燃烧法制备了钙钛矿型复合氧化物La0.3Ca0.7FeO3,并用X-射线衍射分析,扫描电镜,X-射线能谱仪对纳米晶体的晶型、晶粒大小、形貌及组成进行表征.用乙炔黑为载体制备功能氧电极,采用三电极体系,测试循环伏安曲线.结果表明：800℃焙烧2 h得到完整的晶体,晶体粒子大小均匀,粒径为17.9 nm,为菱形晶系;同时该氧电极具有明显的电催化特性.     

柴油机技术现状及发展展望

文中提出了现代柴油机技术发展的关键是节能与环保,详细分析了当前柴油机在节约能源和降低排放方面的发展现状及柴油机未来的发展趋势。     

海洋核动力平台不间断逆变电源一种高可靠性工作模式

本文介绍了一种不间断逆变电源高可靠性工作模式,具体而言是海洋核动力平台不间断逆变电源以受控电流源模式在线并网输出,一方面作为交流电网的热备用,另一方面实现有源电力滤波与无功补偿功能。一旦检测到交流电网掉电,逆变电源立刻从电流源模式切换到电压源模式输出,保障负荷的不间断供电。     

Measuring quality of service in dial-a-ride operations: the case of a Canadian city

In many countries, dial-a-ride services are provided by public authorities to elderly and handicapped people who cannot use regular transit. Cost minimization is key to running these services, but one can observe a growing interest in quality measurement and improvement. A first step in improving quality is to define a quality measurement scale specific to dial-a-ride services. A second step is to incorporate quality measurements in mathematical models that serve as a basis for optimization algorithms. To this end, an extensive survey of dial-a-ride users was conducted in Longueuil, the largest suburb of Montreal, Canada. This paper describes the steps of the survey and presents its main conclusions: (1) 56 attributes were identified based on interviews, (2) the questionnaire developed has proved to be reliable and valid, (3) an exploratory factor analysis allowed us to determine 13 dimensions of quality in dial-a-ride services, (4) the most important criteria for users were identified, and (5) population segmenting variables by which subgroups of users can be categorized were also determined. Managerial implications of our results are also discussed.     

Estimating the robustness of questionnaire results: lessons from a mixed-mode survey of expectations for tele-working and road-based business travel

The robustness of questionnaire results to various forms of bias are explored in the context of a dual-mode (web and hardcopy) survey of employers’ anticipations of levels of employee commuting and business travel activity under a range of future ICT scenarios. The questionnaire incorporated several innovative features which, together with the dual-mode format, allowed an unusually wide range of analyses. For example: the robustness of respondents’ opinions was tested by examining the effect of incorporating alternative versions of a briefing text, one being very positive and one very negative, about the role of ICT; instrument bias was identified via detailed comparison of the results from the two versions of the questionnaire; and the impact of exogenous factors which are often ignored or taken as constant was assessed via special supplementary questions. Analysis showed that the robustness of opinions and expectations varied and was influenced by respondent characteristics, and that results from the two versions of the questionnaire differed significantly. It is concluded that opinions and expectations are less robust, and questionnaire results are more subject to bias and myopic interpretation, than is generally recognised and that web-based surveys seem particularly vulnerable to sampling bias. Methods are suggested for measuring robustness, for reducing bias and for validating and contextualising results. The use of contrasting briefing texts is recommended as a means of establishing the robustness of opinions and expectations while supplementary questions are recommended for validating and contextualising SP and SE exercises.

Comparative analysis of household car,motorcycle and bicycle ownership between Osaka metropolitan area,Japan and Kuala Lumpur,Malaysia

The interactions among different types of vehicle ownership including car, motorcycle and bicycle are examined by developing simultaneous vehicle ownership models in this study. Large scale person trip survey data for Osaka metropolitan area, Japan and Kuala Lumpur, Malaysia are used for empirical analysis. The results suggest that population density at residential area significantly and negatively affects car ownership for both areas, and that the effects are larger for Osaka metropolitan area than for Kuala Lumpur. Also, bicycle ownership becomes higher at higher population density area for Osaka area, while higher at lower population density area for Kuala Lumpur, which represents the different usage patterns of bicycle between the two areas.

Time taken for residents to adopt a new public transport service: examining heterogeneity through duration modelling

When a new public transport service is introduced it would be valuable for public authorities, financing organisations and transport operators to know how long it will take for people to start to use the service and what factors influence this. This paper presents results from research analysing the time taken for residents living close to a new guided bus service to start to use (or adopt) the service. Data was obtained from a sample of residents on whether they used the new service and the number of weeks after the service was introduced before they first used it. Duration modelling has been used to analyse how the likelihood of starting to use the new service changes over time (after the introduction of the service) and to examine what factors influence this. It is found that residents who have not used the new service are increasingly unlikely to use it as time passes. Those residents gaining greater accessibility benefits from the new service are found to be quicker to use the service, although the size of this effect is modest compared to that of other between-resident differences. Allowance for the possibility that there existed a proportion of the sample that would never use the new service was tested using a split population model (SPD) model. The SPD model indicates that 36% of residents will never use the new service and is informative in differentiating factors that influence whether Route 20 is used and when it is used.