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11.
考虑了牵引车空驶、带空挂车行驶和带重挂车行驶所引起的成本差异,定义了牵引车运行成本的概念,将总运行成本最小作为调度方案优劣的判别指标,并同时考虑牵引车数量最少。将牵引任务分为四种类型,定义了任务链、虚拟任务、链内交叉和链间交叉的概念,提出了一种求解该类单车场甩挂运输车辆调度无时间窗约束的启发式算法,包括初始调运方案、链内优化、空车调运交叉、牵引车数量优化和链间交叉。最后给出了仿真算例,算法优化后的最终方案与初始方案相比,牵引车数量减少,总运行成本降低,验证了算法的有效性和可行性。  相似文献   
12.
Land use change is strongly modifying the traditional landscape of hilly productive Mediterranean sites. An example of these circumstances is the Langhe region (Piemonte, NW Italy), where woody plantations such as vineyards and orchards have been cultivated on hillslopes for centuries. In this paper we assess landscape changes occurred in the Diano study area (2651 ha) in the 1954–2000 period and we ascertain land use transition paths and rates of this rural ecosystem. Land use mapping obtained from object-oriented analysis of aerial photographs was used to quantify land use changes between 1954 and 2000. To examine the spatio-temporal patterns of land use change over time, a set of spatial statistics capturing different dimensions of landscape change was identified. An increase of landscape heterogeneity from 1954 to the present was observed due to the expansion of orchards and the fragmentation of field crops. A significant portion (55%) of current orchards surface is represented by former field crops, 24% by vineyards and 15% by forests. The strong expansion of hazelnut orchards concurred to the fragmentation of traditional rural landscape was dominated by vineyards, field crops and forests. Hazelnut orchards expansion was mainly located in places where grapes cultivation was less remunerative. A further expansion of hazelnut in the area should be planned, discussed and carefully monitored through change detection studies in order to avoid potential unsustainable use of the land.  相似文献   
13.
This paper analyzes the effects of cell phone usage and economic freedom on motor vehicle death rates by estimating regression models on data for three years across 38 countries. The models incorporate a representative set of motor vehicle fatality determinants. Results indicate that cell phone use has a statistically significant nonlinear impact on highway death rates and that economic freedom does not appear to have an effect.  相似文献   
14.
Electric vehicles (EVs) are energy efficient and often presented as a zero-emission transport mode to achieve long-term decarbonization visions in the transport sector. The implementation of a sustainable transportation environment through EV utilization, however, requires the addressing of certain cost and environmental concerns such as limited driving range and battery-charging issues before its full potential can be realized. Nevertheless, a specific type of use of EVs, namely in taxi services, may elicit positive public opinion, as it promises a commitment toward sustainability in urban life. In light of this, this study proposes an integrated approach that combines EV operation with a conceptual design for shared-ride taxi services. As some productivity loss may be naturally expected due to the time spent in charging, it is important to look at whether such performance loss from the passenger and system standpoints can be offset with ingenuity in operational design. In this study, an EV taxi charge-replenishing scheme that can be coupled with a real-time taxi-dispatch algorithm is designed. The proposed EV charging schemes for taxi services are studied via simulations and the effects of the limited driving range and battery-charging details are examined from a system performance viewpoint. The simulation study also reveals illustrative results on the impact of the EV taxi fleet's operation on the charging system. Next, a real-time shared-taxi operation scheme that allows ride sharing with other passengers is proposed to maximize the operational efficiency. The simulation results suggest that the shared-taxi concept can be a viable option to improve on the limitations caused by EV operation. In addition, the importance of projected charging demands and queue delays at different charging locations are also addressed. Some limitations and a future research agenda are also discussed.  相似文献   
15.
Electric vehicles (EV) use an eco-friendly technology that limits the greenhouse gas emissions of the transport sector, but the limited battery capacity and the density of the battery are the major barriers to the widespread adoption of EV. To mitigate this, a good method seems to be the innovative wireless charging technology called ‘On-Line EV (OLEV)’, which is a contactless electric power transfer technology. This EV technology has the potential to charge the vehicle’s battery dynamically while the vehicle is in motion. This system helps to reduce not only the size of the battery but also its cost, and it also contributes to extending the driving range before the EV has to stop. The high cost of this technology requires an optimal location of the infrastructure along the route. For this reason, the objective of this paper is to study the problem of the location of the wireless charging infrastructure in a transport network composed of multiple routes between the origin and the destination. To find a strategic solution to this problem, we first and foremost propose a nonlinear integer programming solution to reach a compromise between the cost of the battery, which is related to its capacity, and the cost of installing the power transmitters, while maintaining the quality of the vehicle’s routing. Second, we adapt the multi-objective particle swarm optimization (MPSO) approach to our problem, as the particles were robust in solving nonlinear optimization problems. Since we have a multi-objective problem with two binary variables, we combine the binary and discrete versions of the particle swarm optimization approach with the multi-objective one. The port of Le Havre is presented as a case study to illustrate the proposed methodology. The results are analyzed and discussed in order to point out the efficiency of our resolution method.  相似文献   
16.
本文为了解决物联网所连接对象的多样性带来的标识体系存在不兼容、相互矛盾的问题,基于车联网RFID汽车电子标识的使用特点,创造性地提出将OID编码和汽车电子标识编码相结合的方案。首先简单介绍了基于发证机构及时间和基于汽车VIN码的两种OID编码规则;然后提出了OID编码在汽车电子标识芯片中的规划,主要是内存分配方案;最后介绍了相应区域的读写操作的具体方法。  相似文献   
17.
周翠兰 《价值工程》2014,(11):324-325
本文介绍了汽车尾气对人类健康和生态环境的危害,及其生成机理和影响因素并简述汽车尾气治理与发展。  相似文献   
18.
In a bid to reduce greenhouse gas emissions, several countries worldwide are implementing policies to promote electric vehicles (EVs). However, contrary to expectations, the diffusion speed of EVs has been rather slow in South Korea. This study analyzes consumer preferences for the technological and environmental attributes of EVs and derives policy and environmental implications to promote market diffusion of EVs in South Korea. We conduct a choice‐based conjoint survey of 1,008 consumers in South Korea and estimate the consumer utility function using a mixed logit model considering consumer heterogeneity. Based on the consumer utility function, we analyze consumers' willingness‐to‐pay (WTP) for EV attributes such as driving range, charging method, charging time, autonomous driving function, carbon dioxide (CO2) reduction rate, and purchase price. The results indicate that the current low acceptance of EVs is due to their relatively high price and lack of a battery charging technology that satisfies consumers' expectations of the charging method and time. One interesting finding is that Korean consumers have a relatively higher WTP for the CO2 reduction rate of EVs than consumers in other countries; however, they do not consider CO2 reduction over other technological attributes when choosing EVs. This implies that the rate of CO2 reduction of EVs is not an important factor for South Korean consumers when buying EVs. We also calculate the effect of CO2 reduction with the market penetration of EVs and find that CO2 reduction through the diffusion of EVs depends on the country's electricity generation mix.  相似文献   
19.
As in other emerging nations, in Brazil, the motor vehicle industry is considered to be strategically important for economic development because of its backward and forward linkages and possibilities for export-led growth. This study analyses prospects for the industry by estimating an industry-level cost function that includes output of both vehicles and component parts with capital, labour and intermediate goods as inputs. The cost elasticity of output (an indicator of scale properties) and the elasticity relationships among inputs are explored. One unexpected outcome of the work that appears to be robust is that during early years of the study period, the industry had constant returns or even diseconomies of scale. However, during later years, when output was greater, there were economies of scale. This finding is likely the result of some combination of the entry of new firms, the development of new models or technological change. The study concludes that if firm output can be increased, economies of scale can be expected to strengthen the position of the Brazilian industry in the international marketplace.  相似文献   
20.
传统的无线定位方法直接应用于车辆自组织网络(VANET)时,会被窃听方利用定位信息,从而导致严重的安全隐患。为此,提出基于Bancroft方法的双群组合定位算法,用于保障车辆自组织网络中车辆定位的安全性和准确性。算法利用两个群组的智能车辆节点分别进行定位,利用两组解分别反求伪距值,如果所获得的伪距值与经过节点钟差修正后的原始伪距值基本一致,则认为这一组解为最终的定位结果,从而保证了定位的正确性。同时,双群定位的信息分散性保证了系统整体的安全性。理论分析及算法仿真表明,双群联合定位算法可使窃听方的误码率稳定在较高水平。  相似文献   
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