A local bicycle helmet ‘law’ in a Swedish municipality – the structure and process of initiation and implementation

On May 1, 1996, the Municipality of Motala in Sweden introduced a local bicycle helmet ‘law.’ It is, however, not an official law in a legal sense, but a municipally endorsed recommendation supported by promotional activities. This ‘law’ applies to children (ages 6–12), although the objective is to increase helmet use among cyclists of all ages. The study is a qualitative evaluation of the structure and process during initiation and implementation of the Motala bicycle helmet law. The aim was to describe the activities that were carried out, which actors took part and the opinions of the most closely involved actors. The results are based on analysis of written material and on interviews with eight of the actors. The mass media focused much attention on the bicycle helmet law, especially during the first six months after its introduction. The name helmet law was presumably of significance in this context. It is essential that relevant target groups provide sufficient support and that committed individuals initiate and promote the work, which, however, must not become dependent on a single individual. All issues concerning bicycle helmets should be coordinated with the law. Also, continuous engagement of the municipal government and a strategy for the control and follow-up of the law are needed. Local bicycle helmet laws of this type have a potential to produce a long-lasting effect on helmet use, provided some of the problems encountered can be avoided and some of the promotional activities are intensified.     

Modeling mobile health service delivery to Syrian migrant farm workers using call record data

A significant number of Syrian refugees under temporary protection in Turkey work in agriculture seasonally in various rural areas during several months a year. These migrant farm workers and their families are deprived of access to the regular health care system and preventive services due to their remote locations. The government supports the delivery of different types of mobile health care services, such as vaccination for children, reproductive health and screening services. While planning the mobile health care service delivery, it is critical to know where the refugees will work during what time frame; hence the demand for the services. By analyzing the call record data of a major mobile network operator in Turkey, we quantify the increase in the volume of calls made by Syrian refugees in various agricultural areas during the harvesting season of local crops. This information helps us to forecast spatial and temporal distribution of demand for mobile health care services at a fine granularity. Taking demand over multiple periods as input into a mathematical programming model, we optimize the routing of mobile clinics that visit locations close to where refugees are concentrated over the given planning horizon. We consider three hierarchical objectives. Given the availability of a number of mobile clinics at community health centers in the districts, the first objective aims to maximize the percentage of refugees that can benefit from each service type within pre-defined close distances. The second objective minimizes the number of clinics needed while covering the maximum percentage of refugees. The third objective minimizes the total travel distance of the clinics, while keeping the maximum coverage level using a minimum number of clinics to achieve this level. We quantify the benefits of centralized planning (by the province directorate) over decentralized planning (by each district separately). We also show the trade-off between the required number of clinics and coverage of potential patients.     

漂浮的公交绿岛:扬州古运河线性文化遗产的景观复兴策略

线性文化遗产指“在拥有特殊文化资源集合的线形区域内的物质和非物质的文化遗产族群,往往是出于人类特定目的而形成的重要纽带”.中国大运河在时间上延续数千年、空间上贯穿南北地区,具有明显的线性文化遗产特征.然而,城市化进程的加速给大运河沿线的文化遗产保护和两岸居民的思想观念、生活方式等带来了极大冲击.当下,对大运河线性文化遗...     

无人机视频情报的压缩传输技术

视频图像信号是无人机主要的侦察信息.文中介绍了视频图像信号的数字压缩传输技术,重点讨论了几种压缩编码方法,给出了模拟视频数字化压缩传输方案,并进行了性能分析.     

Vehicle routing optimization with soft time windows in a fuzzy random environment

This paper is concerned with a vehicle routing problem with soft time windows (VRPSTW) in a fuzzy random environment. Two objectives are considered: (1) minimize the total travel cost and (2) maximize the average satisfaction level of all customers. After setting up the model for the VRPSTW in a fuzzy random environment, the fuzzy random expected value concept is used to deal with the constraints and its equivalent crisp model is derived. The global–local–neighbor particle swarm optimization with exchangeable particles (GLNPSO-ep) is employed to solve the equivalent crisp model. A case study is also presented to illustrate the effectiveness of the proposed approach.     

A logistics model for emergency supply of critical items in the aftermath of a disaster

This paper proposes a logistics model for delivery of prioritized items in disaster relief operations. It considers multi-items, multi-vehicles, multi-periods, soft time windows, and a split delivery strategy scenario, and is formulated as a multi-objective integer programming model. To effectively solve this model we limit the number of available tours. Two heuristic approaches are introduced for this purpose. The first approach is based on a genetic algorithm, while the second approach is developed by decomposing the original problem. We compare these two approaches via a computational study. The multi-objective problem is converted to a single-objective problem by the weighted sum method. A case study is presented to illustrate the potential applicability of our model. Also, presented is a comparison of our model with that proposed in a recent paper by Balcik et al. [6]. The results show that our proposed model outperforms theirs in terms of delivering prioritized items over several time periods.     

Combining service frequency and vehicle routing for managing supplier shipments

This paper proposes a new approach to designing inbound material collection routes that considers pick-up frequency and spatial design as joint decisions to minimize total logistics (transportation plus inventory) cost. The clustering-based optimization uses an approximation to the actual cost of a routing solution without actual route construction. We show that the problem is analogous to a single-source fixed-charge facility location problem, and near-optimal solutions can be found using an efficient heuristic algorithm. Tests show the effectiveness of how this model is formulated and a case study demonstrates that substantial total cost savings can be achieved in realistic applications.     

提高DSRC道路信标定位精度的最大信号法及其工程实现

本文概述了中国外贸出口体制的改革进展和成就,探讨了WTO对出口体制的要求及中国出口体制与之相比存在的差距,并按照WTO原则和社会主义市场经济要求,对中国入世后进一步完善出口体制提出12个方面的主要措施。     

Bi-objective decision support system for routing and scheduling of hazardous materials

This paper presents a Pareto-based bi-objective optimization of hazardous materials vehicle routing and scheduling problem with time windows and shows its application to a realistic hazardous material logistics instance. A meta-heuristic solution algorithm is also proposed, which returns a set of routing solutions that approximate the frontier of the Pareto optimal solutions based on total scheduled travel time and total risk of whole transportation process. It works in a single-step fashion simultaneously constructing the vehicle route and selecting the optimal paths connecting the routed locations from a set of non-dominated paths obtained in terms of travel time and risk value.     

铁路编组站阶段计划动态调整方法研究

铁路编组站阶段计划执行过程中的不确定事件导致其无法持续最优,阶段计划动态调整方法对于提高编组站作业效率具有重要意义。研究提出包括时间预测、动态车流推算、计划调整、计划实施、实时信息采集反馈等步骤的阶段计划动态调整流程,通过计算残差相关系数进行数据属性相关性分析和降维处理,利用机器学习方法和神经网络模型预测各阶段作业过程用时,建立基于作业过程用时精准预测的动态车流推算模型,对动态车流推算过程进行符号化描述,提出模型的约束条件和目标函数,设计基于蚁群算法的编组站动态车流推算模型求解算法。结果表明,作业过程用时预测误差随训练集样本数量增大而逐渐减小,蚁群算法计算时间满足阶段计划动态调整实际应用的需要。