美军物流关键技术的应用及启示

现代战争是高技术条件下非线式、非对称的局部战争。战争爆发的突然性,作战进程加快和作战空间膨胀都使战时物资消耗量剧增,使得军事物流面临更加艰巨的任务。无论是海湾战争,还是伊拉克战争,美军都采用了先进的军事物流技术,确保了战时后勤效能的发挥。美军若干物流关键技术的成功运用,可为我军构建现代军事物流系统提供有益启示。1美军现代军事物流的关键技术1)电子数据交换技术。为处理军事物流作业过程中产生的种类繁多、数量巨大的相关信息,推动电子商务的应用,美军已开发出了完善、成熟的电子数据交换(Electronic D ata Interchange…     

萎缩性胃炎胃泌酸储备功能的研究

采用五肽胃泌素刺激试验对47例慢性萎缩性胃炎（CAG）进行胃液分析，并和49例慢性浅表性胃炎（CSG）进行对照，以测定CAG患者胃酸分泌的储备功能。结果：①CAG患者BAO、MAO和PAO均明显降低，平均壁细胞数4．9亿个。非分泌状态的储备壁细胞3．7亿个。CSG平均壁细胞数8．1亿个，6．5亿个是非分泌状态的储备壁细胞，大约是CAG的1．7倍，表明CAG胃泌酸储备功能降低。②CGG患者胃液分泌量明显减少，但空腹胃液及五肽胃泌素刺激后胃液［H+］和CSG相同，说明CAG现存壁细胞的功能正常。③五肽胃泌素刺激后［H+］及胃液分泌量在CAG和CSG均明显增加，说明H+分泌速率代偿性增强，因此胃泌酸储备功能包括二个方面即壁细胞的数量和壁细胞对H+的分泌速率。     

Assessing the CO2 impact of current and future rail track in the UK

This paper investigates the CO₂ impact of current and future UK rail track and estimates the material, process and transport emissions associated with construction, maintenance and end-of-life activities for designs at high and low traffic loads. Analysis shows that for current track configurations, track with concrete sleepers has the lowest CO₂ impact, followed by steel, hardwood and softwood. Several potential future rail track designs have been analysed including embedded rail and double and quadruple-headed rail. All future track designs have a lower impact than current designs, but this improvement is more marked at high traffic loads. Up to a 40% reduction in CO₂ impact could be achieved if the UK rail network was to move from conventional track design to a double-headed embedded rail design. Key levers for reducing the CO₂ impact of track are identified as service life extension, traffic load reduction and the selection of low impact track designs.     

An integrated model system and policy evaluation tool for maximizing mobility under environmental capacity constraints: A case study in Dalian City,China

This paper presents an integrated model system for mobility maximization based on a quantified specification of environmental capacity, and evaluates policy interaction and effectiveness by simulating a number of policy scenarios. The system is designed to specify the maximum level of car ownership and number of trips by private and public modes subject to an environmental capacity constraint defined as the frontier emission under maximum system efficiency. Four types of hypothetical policies (population change, urban sprawl, land-use pattern and network improvement) are designed and the effects of 13 policy scenarios are simulated using data of Dalian City, China. Results reveal that the integrated model system reacts sensitively to policy interventions. The urban sprawl reflected in a changing residential distribution from central to suburban areas is most instrumental from the perspective of pollution alleviation. If the goal is to simultaneously reduce emissions while accommodating mobility, two combinational policy scenarios outperform all others.     

Contracting in highway maintenance and rehabilitation: Are spatial effects important?

Highway agencies around the world strive to improve practices for infrastructure maintenance and rehabilitation, using project delivery policies that range from total ‘in-house’ responsibility to complete privatization, with a number of flexible contracting policies such as performance-based contracting, variants of design-build-maintain, and lane rentals among others between these two extremes. In this paper, we present a methodology that duly accounts for underlying spatial effects and estimates the expected cost savings of innovative contracting policies for highway maintenance and rehabilitation relative to in-house execution of these activities. Spatial econometric modeling is used to analyze highway contract data from 49 countries. We also investigate the marginal effects of key explanatory variables on contract cost savings using spatial multipliers. Our findings show that there are significant relationships between cost savings and contract characteristics, and that there is an apparent direct relationship between the average cost savings of contracts in a country and contract average cost savings and contract sizes in neighboring countries.     

Red-light cameras at intersections: Estimating preferences using a stated choice model

Red-light cameras placed at intersections have the potential to increase safety, but they are often viewed as an invasion of privacy. Preferences for these cameras were explored using a stated choice model that presents key attributes of camera placements. Stated choice models involve careful experimental design, akin to experimental control in laboratory settings. A variety of design approaches were used, settling on a composition of the choice sets people face in the survey. To illustrate the approach, an internet survey was used with a convenience sample containing a high percentage of college students. The results show that while not the case independently, as the number of cameras and fines for violators are simultaneously increased, the preferences for one particular red light cameras program are likely to improve.     

Economic analysis of Japanese air pollution regulation: An optimal retirement problem under the vehicle type regulation in the NOx–particulate matter law

This paper examines the vehicle type regulation that was introduced under the Automobile Nitrogen Oxides–Particulate Matter Law to mitigate air pollution in Japanese metropolitan areas. The vehicle type regulation effectively sets the timing for vehicle retirement by initial registration year and type. However, there was no consideration of cost or efficiency in choosing the timing of retirement. We solve an optimal problem to maximize the social net benefit under the current framework of the vehicle type regulation. The analysis finds that the net benefit can more than double if the optimal retirement timing is chosen. Further, we find that even a simple alteration of the retirement timing can increase the social net benefit by 13%.     

Evaluation of factors for carrier selection in the China Pearl River delta

The efficient integration of logistics modes is critical for international cargo shipping. The local transportation connecting to the export port then plays a vital role in such integration. This paper investigates the problems of carrier selection in the China Pearl River delta area, with respect to international shipping. The analytical hierarchy process (AHP) model is constructed based on a comprehensive industrial interviews and statistical analysis. Rather than simply ranking the given alternatives, we use AHP is used to analyse the weakness and strength of impacting factors in carrier selection. The model is implemented under different types of shipper. Seven criteria are statistically summarized from the questionnaire for evaluating eight different modes. The results are useful to those liner companies serving the PRD region in relationship to port selection and fleet deployment.