Developing environmentally sustainable logistics: Exploring themes and challenges from a logistics service providers’ perspective

The purpose of this paper is to explore themes and challenges in developing environmentally sustainable logistical activities.The approach is explorative with a cross sectional design that takes advantage of ten case studies out of selected logistics service providers (LSPs) operating primarily in the Scandinavian countries.The findings illustrate the major themes by analyzing current and future activities in developing environmentally sustainable logistical activities. In addition, four categories of challenges are identified: customer priorities, managerial complexity, network imbalance, and technological and legislative uncertainties. It is concluded that there is a great need for a holistic perspective where LSPs and product owners together analyze and design future logistical setups.The suggested holistic and integrative model, building on a three-dimensional concurrent engineering framework, provides new opportunities for research. Further research is needed to improve the interrelationship between LSPs and their customers in the development of sustainable logistical solutions.This paper puts forward recommendations for the sustainable development of logistics by combining the results from the case studies with a review of related literature. This will be beneficial for managers and policy makers when they approach sustainable logistical challenges. The emergence and synthesis of themes and challenges are critical for a sustainable society.     

Adaptive scheduling for real-time and temporal information services in vehicular networks

Vehicular networks represent a research area of significant importance in improving the safety, efficiency and sustainability of transportation systems. One of the key research problems in vehicular networks is real-time data dissemination, which is crucial to the satisfactory performance of many emergent applications providing real-time information services in vehicular networks. Specifically, the two issues need to be addressed in this problem are maintenance of temporal data freshness and timely dissemination of data. Most existing works only considered periodical data update via backbone wired networks in maintaining temporal data freshness. However, many applications rely on passing vehicles to upload their collected information via wireless network, which imposes new challenges as the uplink data update will have to compete with the downlink data dissemination for the limited wireless bandwidth. With such observations, we propose a temporal information service system, in which vehicles are able to collect up-to-date temporal information and upload them to the roadside units (RSU) along their trajectories. Meanwhile, RSU can disseminate its available data items to vehicles based on their specific requests. Particularly, in this paper, we first quantitatively analyze the freshness of temporal data and propose a mathematical model to evaluate the usefulness of the temporal data. Next, we give the formulation of the proposed real-time and temporal information service (RTIS) problem, and prove the NP-hardness of this problem by constructing a polynomial-time reduction from 0–1 knapsack problem. Subsequently, we establish a probabilistic model to theoretically analyze the tradeoff between timely temporal data update and requested data dissemination sharing a common communication resource, which provides a deeper insight of the proposed RTIS. Further, a heuristic algorithm, namely adaptive update request scheduling (AURS), is designed to enhance the efficacy of RTIS by synthesizing the broadcast effect, the real-time service requirement and the service quality in making scheduling decisions. The computational complexity and scalability analysis of AURS is also discussed. Last but not least, a simulation model is implemented and a comprehensive performance evaluation has been carried out to demonstrate the superiority of ARUS against several state-of-the-art approaches in a variety of application scenarios.     

轨道交通与地面公交出行信息服务协同框架体系

针对轨道交通与地面公交出行信息共享不畅通、数据质量不高、信息服务体验不佳等问题,围绕信息采集、处理和发布等关键业务环节,系统分析了信息主体、信息客体、时间与环境等信息协同核心要素,提出轨道交通与地面公交出行信息服务协同框架体系,设计了涵盖数据资源整合、后台系统和前端应用的出行信息服务系统框架。同时,在对比分析传统出行信息服务系统建设模式优劣势的基础上,提出“政府引导、企业参与”的系统建设模式和实施路径,以期为轨道交通与地面公交出行信息服务系统的设计、开发、建设和运营提供参考。     

江西省科技中介服务体系研究

通过分析科技中介服务机构的意义、国内科技中介服务体系的现状、我省科技中介服务体系近年来的发展状况,找出我省科技中介服务体系的差距以及目前所面临的问题,并提出发展和完善我省科技中介服务体系的一些建议.     

基于服务水平的公路技术标准分析与评价

针对目前公路建设项目工程可行性研究阶段技术标准论证存在的问题,结合新颁布的《公路工程技术标准》、《公路路线设计规范》,系统地论述了技术标准选择的原则、方法与研究思路;详细地讨论了如何确定适宜的公路技术标准,包括公路等级选用、车道数确定、设计速度选用;提出了基于通行能力和服务水平的技术标准分析与评价方法。应用国道324线碧冈至潮州港支线工程可行性研究为实际工程背景,具体验证了应用通行能力和服务水平评价技术标准的可行性。     

基于AM策略的道路出入口设计研究

道路出入口作为道路的重要节点,影响着整个路网的运行效率及安全。首先分析了道路出入口设计、运营过程中存在的问题,认为出入口布局选址欠规划、出入口设计不佳、出入口附近交通组织不完善等原因是造成道路出入口衔接处交通拥堵的主要原因。借鉴美国出入口管理策略中的相关技术,提出了建立出入口间距标准、采用服务性道路改善路口布局、路口采用远引调头措施等技术,能够有效地提高交通运行的效率以及行车安全性。     

利用AHP法引入服务水平的综合交通阻抗函数模型

针对交通阻抗函数模型进行研究。通过对诸如出行费用、出行时间及交通运输方式的服务水平等影响交通阻抗因素的分析,在充分利用了美国联邦公路局的BPR函数和Davidson阻抗函数的优点的同时,针对这两个函数中同时存在的没有把服务水平作为函数变量的这一不足,重点把服务水平这一影响因素融入到阻抗模型中。在服务水平的分析研究上,从安全性、舒适度和便利度3个层面进行剖析,利用两两比较法、专家评判法和AHP法对服务水平进行量化,使定性参数定量化。然后对模型进行修正,最终得到新的交通阻抗函数修正模型。     

长寿型路面设计探讨

对于黑色路面车流量大、损坏比较严重的路段,采用黑色原路面加罩白色路面结构层方法实际运用效果比较理想,能使道路寿命大大延长。该文主要介绍了长寿型路面的设计与应用实践。     

混凝土结构耐久性探析

目前,在国内的结构设计过程中主要侧重荷载作用下结构的强度需要而未能充分考虑环境作用下结构的耐久性,对于结构的耐久性只是作为一种概念受到关注而没有进行专门的耐久性设计。这就直接导致结构使用性能差、寿命短甚至频发事故的不良后果,与国际结构工程界日益重视耐久性、安全性、适用性的趋势相违背,与符合结构动态和综合经济性的要求相违背。针对这一问题,重点阐述结构设计及使用过程中耐久性的重要性,对结构裂缝的种类和产生的原因作较全面的分析、总结,找出控制裂缝的可行办法,达到增强耐久性的目的。     

轴载车型选择对路面结构设计的影响

文中介绍了轴载换算的意义、轴载换算的机理和交通统计车型及路面设计汽车的分类情况,分析了汽车型号选择对水泥混凝土路面结构设计的影响,并对轴载换算提出了建议,以提高路面的使用寿命。