格拉斯磁环匀强磁场分析

以毕奥-萨伐尔定律为基础,建立亥姆霍兹线圈以及格拉斯磁环中心磁场分布模型,并计算了它们内部的轴向磁感应强度分布,绘出了空间分布图,分析了轴向磁感应强度与x、y坐标的关系,分析结果得到了亥姆霍兹线圈和格拉斯磁环内部匀强磁场分布区域,通过比较得到格拉斯磁环内部的匀强磁场区域比亥姆霍兹线圈内部的匀强磁场分布区域更大的结论。     

Locating emergency vehicles with an approximate queuing model and a meta-heuristic solution approach

In this paper, the location of emergency service (ES) vehicles is studied on fully connected networks. Queuing theory is utilized to obtain the performance metrics of the system. An approximate queuing model the (AQM) is proposed. For the AQM, different service rate formulations are constructed. These formulations are tested with a simulation study for different approximation levels. A mathematical model is proposed to minimize the mean response time of ES systems based on AQM. In the model, multiple vehicles are allowed at a single location. The objective function of the model has no closed form expression. A genetic algorithm is constructed to solve the model. With the help of the genetic algorithm, the effect of assigning multiple vehicles on the mean response time is reported.     

放宽条件定点集结模式下编组站车辆 集结排队系统分析

集结模式决定了货车集结过程的结束条件，定点集结是一种高效率的集结方式，有利于提高运输质量.针对放宽条件定点集结模式下编组站车辆集结过程，建立离散时间批到达批服务排队模型，利用嵌入式马尔可夫链方法求得离去时刻瞬时系统集结车辆队长分布，并求得任意时刻车辆集结队长分布，在此基础上分别分析了最小编成辆数，车组大小分布，车流到达强度，服务时间间隔分布对车辆平均集结队长，集结延误时间，效率，一昼夜发送车流量等系统指标的影响.分析结果表明，各因素对车辆集结排队系统影响明显.因此，利用本文提出的模型能为编组站的精细化管理和车流组织优化提供决策参考.     

高速公路路基施工及其防护技术探讨

结合某高速公路施工实例,提出公路路基施工前的准备工作,探讨公路路基的施工技术,同时提出高速路路基防护可采取的技术措施,为同类工程提供指导的同时也对以后公路路基施工环节开展更深层次的研究起到一定的参考作用.     

桥梁模板施工技术应用性研究

桥梁模板是桥梁施工中的重要工具。通过搜集国内外桥梁模板资料,研究总结并提出解决模板工程在桥梁施工中存在各种问题的办法,将对提高工程质量、加快施工速度、提高劳动生产率、降低工程成本和实现桥梁工程的文明施工起到一定的推动作用。     

论孔子人才观的历史定位与普适价值

孔子的人才观虽然产生于春秋时期动荡的社会背景下,却揭示了人才的最本质内涵———＂仁、智、勇＂。三者作为人才内涵的核心三要素,形成一个内在的三角稳定结构,它能够持久地推动包括成才在内的人的生命境界的发展,因而具有超越时代和社会阶层的普适价值。     

变邻域搜索求解公共交通乘务调度问题

公共交通乘务调度问题是一个将车辆工作切分为一组合法班次的过程,它是NP难问题,许多求解方法的效率都与班次评价密不可分,本文通过裁剪TOPSIS方法(Technique for Order Preference by Similarity to an Ideal Solution)设计了TOPSIS班次评价方法.此外,通过裁剪变邻域搜索算法使之适合求解乘务调度问题,提出了基于变邻域搜索的乘务调度方法(Crew Scheduling Approach Based on Variable Neighbourhood Search,VNS),其中,并入了TOPSIS班次评价方法在调度过程中进行班次评价,设计了两种带概率的复合邻域结构以增加搜索的多样性,帮助跳出局部最优,在VNS中利用模拟退火算法进行局部搜索.利用中国公共交通中的11组实例进行了测试,测试结果表明,VNS优于两种新近提出的乘务调度方法,且其结果关于班次数接近于下界.     

Compliance with MARPOL Annex VI regulation 14 by ships in the Gulf of Guinea sub-region: Issues,challenges and opportunities

The negative environmental and health impacts association with high sulphur dioxide emissions from shipboard machineries have been raised by various stakeholders within the marine transportation sector. It is against this backdrop that the International Maritime Organisation under the MARPOL Annex VI regulation 14 has capped sulphur emission to 0.1% for Sulphur Emission Control Areas and 0.5% for the other shipping nations. However, ship owners in the Gulf of Guinea (GoG) sub-region are facing multitudes of challenges in meeting up with this new IMO regulation. This paper aims to identify the main barriers hampering effective compliance to this new regulation by ships operating in the GoG, rank the barriers, and then discuss the possible opportunities that may arise as a result of addressing the challenges. To identify the main barriers, experts with several years of experience in the maritime industry from Ghana and Cameroun were used while multi-criteria decision-making (MCDM) method combining analytic hierarchy process (AHP) and technique for order preference by similarity to ideal solution (TOPSIS) was employed to rank the barriers. Other methods such as fuzzy AHP (FAHP), rank-order centroid (ROC) and TOPSIS were combined to validate the result of the study. The findings indicate that lack of infrastructure, lack of comprehensive marine air pollution laws and high capital and operational costs of sulphur reduction solutions emerged as the top three ranked barriers. The findings of this study can be useful to ship owners and policy makers in dealing with the issues of marine air pollution.     

Adoption of alternative fuel vehicles: Influence from neighbors,family and coworkers

During the last years, many governments have set targets for increasing the share of biofuels in the transportation sector. Understanding consumer behavior is essential in designing policies that efficiently increase the uptake of cleaner technologies. In this paper we analyze adopters and non-adopters of alternative fuel vehicles (AFVs). We use diffusion of innovation theory and the established notion that the social system and interpersonal influence play important roles in adoption. Based on a nationwide database of car owners we analyze interpersonal influence on adoption from three social domains: neighbors, family and coworkers. The results point primarily at a neighbor effect in that AFV adoption is more likely if neighbors also have adopted. The results also point at significant effects of interpersonal influence from coworkers and family members but these effects weaken or disappear when income, education level, marriage, age, gender and green party votes are controlled for. The results extend the diffusion of innovation and AFV literature with empirical support for interpersonal influence based on objective data where response bias is not a factor. Implications for further research, environmental and transport policy, and practitioners are discussed.     

公路工程施工管理质量研究

公路工程施工管理直接关系到工程项目的质量,在施工中加强管理控制是十分必要的,结合公路工程施工管理的特点,对影响公路工程管理质量的因素进行分析,并提出具体解决对策,对类似工程施工有一定的指导意义.