‘Regulated deregulation’ of local bus services—An appraisal of international developments

The deregulation of the British bus sector (outside London) in 1986 was the start of a debate on the merits of ‘deregulation’ and ‘competitive tendering’. The period that followed was rich in lessons. New Zealand was at the time the only other country engaging in a reform based upon market initiative (implemented in 1991). Other countries chose for a less extreme and more consensual way to introduce competitive incentives, choosing the fundamentally different competitive tendering (CT) path. As a result, the so-called ‘Scandinavian model’ developed, based upon the London example of route tendering. Later the Netherlands adopted a network tendering approach, resembling the French practice of network tendering though with more operator freedom.     

牵引用3300V IGBT/FRD芯片组设计与开发

针对轨道交通绝缘栅双极晶体管(IGBT)的应用特点,利用计算机仿真技术对终端结构进行优化,提高耐压特性;采用台面栅结构,提高开关速度;通过控制载流子注入效率,改善Vceon与Eoff的折中关系,降低芯片损耗;采用先进元胞设计技术,提高芯片短路能力,从而提高芯片可靠性;通过超低阳极掺杂控制阳极注入效率,免除局部寿命控制,降低FRD的反向漏电流。研究开发了3300V IGBT及其配套FRD芯片,满足轨道交通的应用要求。     

System convergence — The potential for an integrated road transport environment

This chapter discusses the potential for co-ordinating developments in Road Transport Informatics (RTI) in what could otherwise be a number of fragmented approaches, in order to approach what the DRIVE programme calls the Integrated Road Transport Environment (IRTE). The discussion is presented with particular reference to European developments such as the PROMETHEUS and DRIVE research programmes, but is intended to encompass possible progress towards worldwide standardisation.The role of consensus formation in Europe in the DRIVE projects SECFO and TARDIS is described. The importance of dynamic route guidance and of automatic debiting systems are highlighted in identifying the likely impetus towards the implementation of RTI systems. Finally, some outstanding issues are presented briefly, and the possible emergence of international standards leading to compatible systems worldwide is discussed.     

REVERSAL OF THE DOUBLE－STRANDED－RNA－INDUCED INHIBITION OF PROTEIN SYNTHESIS BY A CATALYTICALLY INACTIVE MUTANT OF THE PROTEIN

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The analysis of bus costs and revenues by time period

Bus operators serve many markets characterized both spatially and temporally. An objective of these companies is to tailor fares and service provision to these myriad markets. The past 20 years have seen an unprecedented desire by bus companies to analyse costs and revenues at the micro level to permit this tailoring. This was initially on a route‐by‐route basis and later on a time‐of‐day/day‐of‐week (or time period) basis. The methodology was developed in three stages: (1) apportioning methods for allocating costs and revenues to route level were developed in the United Kingdom and the U.S.A. in the period 1968 to 1974; (2) further developments post 1974 were chiefly in the U.S.A. and Australia and concentrated on prediction methods for incremental costs resulting from expanding/contracting service at particular times of day; and (3) there was a resurgence of interest in the U.K. post 1979 with analysis of both allocated and incremental costs and revenues. This assumed great practical interest with deregulation of the industry in 1986.

The paper traces the development of the literature over the period and indicates that costing methodologies have been extensively analysed but revenue methodologies are still in their infancy. On the costing side, two methodologies, one from the U.K. and one from Australia, are available. The paper describes these two techniques and, in comparing them, identifies a trade‐off between predictive accuracy and simplicity of application. The paper concludes that the development of micro‐level analytical techniques has proved to be both practical and desirable. Areas for potential future research are also identified.     

Commercializing management and financing of roads in developing and transition countries

The road sector reforms undertaken by a growing number of developing and transition countries during the past 10-20 years are described. The problems these countries share with industrialized countries and the additional factors that also affect them--large backlogs of deferred maintenance, an acute shortage of funds and dysfunctional road agencies--are also described. The paper then describes how these countries have restructured road management by separating planning and management of roads from implementation of works, provided road agencies with more autonomy, created more effective oversight, introduced annual performance agreements and turned the road agency into a more commercial organization paying market-based wages. In relation to road financing, road tolls and toll roads are touched on briefly before the new style road funds that have recently been set up in these countries are detailed. The paper then describes how they were established and their basic operating modalities--revenues only from charges related to road use (with one notable exception), no abstraction of revenues from other sectors, proactive management and oversight provided by a board of directors that includes members nominated by road users and the business community.     

Validating the results of a route choice simulator

This paper describes the validation of a route choice simulator known as VLADIMIR (Variable Legend Assessment Device for Interactive Measurement of Individual Route choice). VLADIMIR is an interactive computer-based tool designed to study drivers’ route choice behaviour. It has been extensively used to obtain data on route choice in the presence of information sources such as Variable Message Signs or In-Car Navigation devices. The simulator uses a sequence of digitized photographs to portray a real network with junctions, links, landmarks and road signs. Subject drivers are invited to make journeys between specified origins and destinations under a range of travel scenarios, during which the simulator automatically records their route choices. This paper describes validation experiments carried out during the period Summer 1994 to Autumn 1995 and reports on the results obtained. Each experiment involved a comparison of routes selected in real life with those driven under simulated conditions in VLADIMIR. The analysis included investigation of the subjects’ own assessment of the realism of the VLADIMIR routes they had chosen, a comparison of models based on the real life routes with models based on VLADIMIR routes, and a statistical comparison of the two sets of routes. After an extensive series of data collection exercises and analyses, we have concluded that a well designed simulator is able to replicate real life route choices with a very high degree of detail and accuracy. Not only was VLADIMIR able to precisely replicate the route choices of drivers who were familiar with the network but it also appears capable of representing the kind of errors made and route choice strategies adopted by less familiar drivers. Furthermore, evidence is presented to suggest that it can accurately replicate route choice responses to roadside VMS information.     

Transport studies research in U.K. universities

British universities have entered a period of crisis. The outward manifestation of the current malady has appeared as a general cut-back in university spending. Until two or three years ago, most universities looked forward to a modest growth in activity. This has now been changed and the expectations of growth have been replaced by the reality of consolidation and modest decline. However, the universities are not alone in their dilemma. The general downturn in economic prosperity has left few institutions unscathed. Most universities, both in Britain and abroad, have therefore been forced to review their expectations and their ongoing commitments in teaching and research. The review of university activity goes much deeper than the immediate problems of finance. The current soul-searching has been sparked off by the crisis of finance, but has roots which go much deeper and touch on the very fundamentals of university education itself. In a sense, one is witnessing a belated form of public accountability: what is the purpose of a university; should its subjects be demonstrably relevant (both in themselves, as well as in their capacity to prepare students for a career); should universities engage in research and, if so, should it complement their teaching functions or be additional to it? These, and many other issues, are currently being discussed, and it is specifically with reference to their role in the field of transport research that this paper is addressed.     

The biogeochemical cycling of methane in Ria de Vigo, NW Spain: Sediment processing and sea–air exchange

Methane (CH₄) concentrations were measured in the water column, in sediment porewaters, and in atmospheric air, in the Ría de Vigo, NW Spain, during both the onset (April 2003) and at the end of (September 2004) seasonal upwelling. In addition, CH₄ concentration and stable isotopic signatures (δ¹³CH₄) were measured in porewaters, and sediment methanogenesis and aerobic oxidation of CH₄ were determined in sediment incubations. Surface water column CH₄ (2 m depth) was in the range 3–180 nmol l^− 1 (110–8500% saturation) and followed a generally landward increase but with localised maxima in both the inner and middle Ría. These maxima were consistent with CH₄ inputs from underlying porewaters in which CH₄ concentrations were up to 3 orders of magnitude higher (maximum 350 μmol l^− 1). Surface water CH₄ concentrations were approximately three times higher in September than in April, consistent with a significant benthic CH₄ flux driven by enhanced sediment methanogenesis following the summer productivity maximum. CH₄ and δ¹³CH₄ in sediment porewaters and in incubated sediment slurries (20 °C) revealed significant sediment CH₄ oxidation, with an apparent isotopic fractionation factor (r_c) of  1.004. Using turbulent diffusion models of air–sea exchange we estimate an annual emission of atmospheric CH₄ from the Ría de Vigo of 18–44 × 10⁶ g (1.1–2.7 × 10⁶ mol). This estimate is approximately 1–2 orders of magnitude lower than a previous estimate based on a bubble transport model.     

The importance of polynyas, ice edges, and leads to marine mammals and birds

The correlation between areas of open water in ice-covered seas and increased biological productivity has been noted for some time. To date, most attention has been focused on larger polynyas, such as the Northeast Water and the Northwater. Although spectacular in their own right, these large polynyas represent only part of a vitally important continuum of biological productivity that varies significantly between geographic areas and ice habitats, that includes the multi-year pack of the polar ocean and small localized polynyas in annual ice. Surveys of the distribution and abundance of ringed seals in the Canadian Arctic Archipelago have shown differences in density that are correlated with the presence or absence of polynyas. There is also significant variation in the biological productivity of polynya areas of the Canadian High Arctic Archipelago and northern Greenland, all of which receive inflow from the polar basin. Long-term studies of polar bears and ringed seals in western Hudson Bay and the eastern Beaufort Sea show significant but dissimilar patterns of change in condition and reproductive rates between the two regions and suggest that fundamentally different climatic or oceanographic processes may be involved. Projections of climate models suggest that, if warming occurs, then the extent of ice cover in Hudson Bay may be among the first things affected. Long-term studies of polar bears and ringed seals in the eastern Beaufort Sea and Hudson Bay would suggest these two species to be suitable indicators of significant climatic or oceanographic changes in the marine ecosystem.