我国粮食物流园区运作研究

随着粮食物流业的发展,粮食物流园区的地位和作用也日益受到重视。如何做好具有现代物流和供应链管理理念的粮食物流园区运作,已成为关注的焦点。本文分析了我国粮食物流园区建设的必要性和可行性、发展现状及存在的问题,并在此基础上提出了我国粮食物流园区运作的几点建议。     

From broken windows to a renovated research agenda: A review of the literature on vandalism and graffiti in the rail industry

The execution of vandalism and graffiti on rail property has a significant impact on rail authorities, the patronisation of rail services, expenditure, and the timely operation of services. There are also important social costs which stem from passengers feeling unsafe, not to mention the environmental costs of removing graffiti and repairing vandalism. In this review paper, we focus on the social, non-technical determinants of and deterrents to vandalism and graffiti in the rail industry. First, we consider the definitions of graffiti and vandalism that are often conflated. After providing some clarification on terminology, and proposing a media-centred approach to vandalism and graffiti, we consider various theorisations of the psychosocial determinants of vandalism and graffiti behaviour. We then turn to an empirical discussion of different technical and social, non-technical prevention programmes that have been trialled. With a focus on identifying what works and under what circumstances, we refer to international case studies of successful vandalism reduction initiatives from Europe, the United Kingdom, the United States of America and Australia. Based on a review of literature and practice, we outline a future research agenda to address vandalism and graffiti. We recommend lines of further research covering: theory, empirical data collection and practical initiatives. Specifically, we note the need for a trans-theoretical model of vandalism and graffiti, further ethnographic research and improved evaluation and benchmarking strategies. This is the first review dedicated to the topic of vandalism and graffiti in the rail industry and the first review of non-technical, social deterrents to vandalism and graffiti broadly.     

Roadmap for free-floating bikeshare research and practice in North America

ABSTRACT

The deployment of smartphone-operated, non-station-based bicycle fleets (“dockless” or “free-floating” bikeshare) represents a new generation of bikesharing. Users locate bikes in these free-floating systems using Global Positioning Systems (GPS) and lock bikes in place at their destinations. In this paper, we review current free-floating bikesharing systems in North America and discuss priorities for future research and practice. Since launching in 2017, free-floating bikeshare has expanded rapidly to encompass 200+ systems operating 40,000+ bikes within 150+ cities. In contrast with previous systems, free-floating systems operate almost exclusively using commercial “for-profit” models, amidst concerns of financial sustainability. Governance for these systems is in early stages and can include operating fees, fleet size caps, safety requirements, parking restrictions, data sharing, and equity obligations. We identify research and practice gaps within the themes of usage, equity, sharing resources, business model, and context. While some existing bikesharing literature translates to free-floating systems, novel topics arise due to the ubiquity, fluidity, and business models of these new systems. Systems have numerous obstacles to overcome for long-term sustainability, including barriers common to station-based systems: limited supportive infrastructure, equity, theft or vandalism, and funding. Other unique obstacles arise in free-floating bikeshare around parking, sidewalk right of ways, varied bicycle types, and data sharing. This review offers background in and critical reflection on the rapidly evolving free-floating bikeshare landscape, including priorities for future research and practice. If concerns can be overcome, free-floating bikeshare may provide unprecedented opportunities to bypass congested streets, encourage physical activity, and support urban sustainability.     

百米先锋--两冲程巨人杀手的回归

这是一款纯粹的非常优秀的专用跑车,它的优秀表现来自雅马哈RD350双缸发动机,47．8KW的功率,10000r/min的转速,使这款重约125kg的大家伙优美地跑动起来。     

系统控制器--用戴勒·爱哈德方案注入了氮的新哈利--一位美国人的杰作

哈利骑士拉斯·拉森在全国汽车比赛协会上炫耀:他的车能够以322km的时速奔跑.确实让人难以置们.当他谈论到--一种小型的65ml的发动机,它每小时能产生32000转数,并且能产生7.68kW的能量时,你的困惑释然.     

Drift At Sea

数百年前,航海家们靠着"自然动力"的帆船搏击大海,探究地球的另一端,成就发现新大陆的丰功伟业。而此后的数百年间,人类则步入了一个"人定胜天"的新时代,自然动力与人力渐渐退至一隅,海上驶过的是邮轮,供娱乐的则有游艇,快艇。在蔚蓝的地中海,帆船已经融入生活。     

腐败成因之文化探析

人们熟知"经济贫穷"和"制度不健全"是腐败产生的两大原因,但本文通过对家庭主义的深厚历史和家庭主义的特征两方面进行理论和实证分析,以文化是一种态度、信念、价值观为标准,认为由于家庭主义核心价值是强调家庭义务和家族忠诚,家族主义作为一种文化是腐败产生的一个不可忽视的重要原因.     

Modeling and simulation of vehicle projection arrival–discharge process in adaptive traffic signal controls

Real‐time signal control operates as a function of the vehicular arrival and discharge process to satisfy a pre‐specified operational performance. This process is often predicted based on loop detectors placed upstream of the signal. In our newly developed signal control for diamond interchanges, a microscopic model is proposed to estimate traffic flows at the stop‐line. The model considers the traffic dynamics of vehicular detection, arrivals, and departures, by taking into account varying speeds, length of queues, and signal control. As the signal control is optimized over a rolling horizon that is divided into intervals, the vehicular detection for and projection into the corresponding horizon intervals are also modeled. The signal control algorithm is based on dynamic programming and the optimization of signal policy is performed using a certain performance measure involving delays, queue lengths, and queue storage ratios. The arrival–discharge model is embedded in the optimization algorithm and both are programmed into AIMSUN, a microscopic stochastic simulation program. AIMSUN is then used to simulate the traffic flow and implement the optimal signal control by accessing internal data including detected traffic demand and vehicle speeds. Sensitivity analysis is conducted to study the effect of selecting different optimization criteria on the signal control performance. It is concluded that the queue length and queue storage ratio are the most appropriate performance measures in real‐time signal control of interchanges. Copyright © 2010 John Wiley & Sons, Ltd.