Integrated Control Methodologies for Road Vehicles

Summary This paper considers the scope, methodologies and architectures for the design and development of interacting control systems in road vehicles. The increasing use of electronic controls leads inevitably to an increase in overall system complexity. Given the time and economic constraints of the modern automotive industry, it is not feasible to synthesise and validate the full set of vehicle controls in the form of a unified and centralized controller. On the other hand a fully decentralized approach to control system development and operation will induce performance limitations from un-modelled or unexpected interactions; at worst, such interactions can cause instability and loss of function. There is now increasing pressure to achieve control coordination whilst maintaining a modular approach to the overall system design. With this in mind, the paper provides a framework to review current practice in integrated vehicle control, assesses recent developments in control integration methodologies that are most relevant to the vehicle application, and formulates an enhanced multi-layer architecture that includes explicit coordination functionality. Overall emphasis is placed on the role of control system architecture, the resulting flow of control information and the implications for control system design. An example from handling dynamics is presented, demonstrating the viability of new and flexible approaches. In conclusion a number of outstanding research problems are highlighted.     

Public/private-sector cooperation in urban transportation: Lessons from ridesharing experiences in Connecticut

An important characteristic of urban transportation policy and planning today is the increasing role that the private sector is playing in identifying and implementing transportation projects. For example, a recent examination of the possible forms of such involvement found that there were four major categories of action that could be used to classify recent private-sector efforts in urban transportation: (1) aid to and/or provision of transportation services; (2) formation of advocacy or advisory groups whose purpose is to influence public policy; (3) sponsorship of transportation studies; and (4) provision of management assistance to public agencies (Gordon, 1982). In many of these efforts, the successful implementation of a project or program required close cooperation between public and private-sector officials. The purpose of this paper is to examine the characteristics of this interaction and explore the implications for transportation planning and policy.Examples of public/private-sector interaction in two Connecticut cities, Hartford and Stamford, are used to illustrate the characteristics of successful transportation program implementation. Although the examples are limited to two cities, and are mainly concerned with one major category of action (ridesharing), the characteristics of the process used and of the results can be applied to other situations where public/privatesector interaction is desired.     

Highway and transportation planning in England

This article presents an overview of highway and transportation planning in England. It covers the division of responsibilities between central and local government; the organisation of the Department of Transport; the planning, financing and implementation of road schemes, both local and national. A very brief review of transport legislation is included.NOTE: This paper was printed before the UK General Election of May 1979. The Department of Transport is now responsible to the Minister of Transport. The Minister has similar responsibilities to those previously exercised by the Secretary of State for Transport as referred to in this paper. The views expressed in this paper are those of the writer and are not necessarily those of the Department of Transport.     

Port system evolution – the emergence of second-tier hubs

Some evidence has emerged of second-tier hubs inserting themselves between hubs and feeder ports, producing a new hierarchy of port networks. This article aims to establish the dynamics of this process based on illustrative cases in Asia, South America, and Europe. Findings reveal spatial factors to include a cluster of small ports with minimal sailing distance within a given range, suitable channel and berth depth, and ideally high capacity inland links. From the economic perspective, demand-side factors include a local captive market and aggregated demand to be captured from other ports, while supply-side factors include diseconomies of scale at traditional hubs, an increase in direct services, an increase in large feeder vessels calling from first-tier hubs which are then transhipped to smaller feeders for serving local ports, and an increase in overland servicing of local smaller ports. From a strategic perspective, vertical and horizontal integration in the shipping sector has produced extensive network economies, whereby shipping lines look to create group-specific port hierarchies, enhanced in the presence of aggressive management strategies and supportive policies. This finding suggests that proactive port stakeholders can in certain circumstances seize the opportunity to capture this role within their port range.     

Port-centric logistics,dry ports and offshore logistics hubs: strategies to overcome double peripherality?

Scotland's low accessibility is reflected in the limited share of Scottish unitised freight traffic coming through Scottish ports. This paper will discuss site development strategies to overcome Scotland's double peripherality (i.e. both physically and institutionally) by restructuring transport chains of large shippers through new corridors. Three competing logistics concepts will be discussed, beginning with the existing load centre terminal that provides direct access to the distant main ports. Second, port-centric logistics based at Scottish ports, and finally, offshore port-centric logistics utilising maritime links to a port-based distribution centre in Zeebrugge. The paper has two interlinked aims. First, to provide a firm theoretical grounding for recent maritime transport geography concepts, which has been lacking in the literature. This will be achieved by examining peripherality and responses to this by states at different scales, thus exploring how the three concepts in this paper can be viewed as attempts at spatial fixes of mobile capital. The second aim develops out of the first, and will explore how the perspective of space is treated in maritime geography as compared with other areas of geography. As a result, the paper pursues a cross-disciplinary approach by utilising theory from economic geography and political geography.     

A Comparison of Adaptive LQG and Nonlinear Controllers for Vehicle Suspension Systems

A design feature of many computer-controlled suspension systems, is their ability to adapt control law parameters to suit prevailing road conditions. Here, for systems employing high bandwidth actuators and state variable feedback control, the benefits of such adaptation are shown to be at best marginal. An optimal adaptive LQG system is compared with a fixed structure nonlinear feedback controller in the context of a simple quarter-vehicle suspension model. Performance comparisons are made, and trends considered under more realistic conditions. In consequence the overall usefulness of this type of adaptation is called into question.     

The coastal barrier resources act of 1982: An assessment of legislative intent,process, and exemption alternatives

Recent coastal barrier legislation demonstrates a growing national concern to protect fragile undeveloped coastal barriers and to prevent the expenditure of federal monies used in promoting their development. The Coastal Barrier Resources Act of 1982 bases designations of undeveloped coastal barriers on previous federal legislation and Department of the Interior rule‐making. This paper examines the legislative intent of Congress and how it was interpreted through the designation process. Alternative strategies to achieve exemption from the Coastal Barrier legislation are discussed as a process, and an analysis is made of an exemption as it occurred in Texas.     

中国的先行者

州数码在北京、上海、广州设有主要分销中心，在各省和省会城市设有10个分销点。为了进一步加强在三、四线城市的覆盖力度神州数码于2005—06年在分销网络中又增加了29个城市,其大陆的分销商总数达到了8．225个，同比增长35％。