A stochastic passenger loading model of airline schedule performance

The passenger loading problem is defined as that of determining the distribution of passengers that will be carried on each flight in a given market over the course of the day. This problem is stochastic in nature, and must take into account the fact that as some flights become booked up, passengers may spill to adjacent flights, or may choose not to fly on that airline. A precise model of the loading process is developed and solved using an efficient numerical procedure. Several approximations are introduced and tested which further improve the overall efficiency. The model represents a more rigorous solution approach than has appeared previously in the literature, and as such could be used to evaluate simpler approximations. It is fast enough, however, to be used as an interactive schedule evaluation and design tool.     

迎接高速公路时代—中国汽车相关技术问题的考察

中国正迎来高速公路时代，高速公路时代安全行车在技术因素方面涉及车辆的构造，道路设施与运行管理，在人的因素方面涉及驾驶习惯。保养与车检，安全运行的宣传教育与管理等。     

Research on the Influence of Small Distance Subway Tunnel Passing through Buildings at Short DistanceEI北大核心

Research purposes: At present, the urban subway is developing rapidly in our country, among which there are many problems. This paper takes a seven-story frame structure office building as research object. In view of the phenomenon that the dome subsidence and the land subsidence rate exceed the early warning in the field construction of the left line tunnel, combing theoretical analysis with the MIDAS-GTS numerical simulation, we took the "building-stratum-tunnel" as the research object, analyzed the influence of small distance tunnel construction process of mine method on the adjacent buildings, and analyzed the influence difference of the construction sequence of the left and right lines. Finally we put forward the relevant engineering technical measures. Research conclusions:(1) The tunnel construction makes the building in the tensile zone, and the structure is easy to be damaged. When the structure is far away from the influence of the excavation, the order of tunnel excavation is not significant. (2) When the surrounding rock is broken and close to the building, it is better to excavate the tunnel far away from the side of the building. At the same time, we should pay attention to taking the reinforcement measures near the side of the building and the intermediate rock column. (3) The research results can be applied to the field of shield construction in subway, and have a good guiding effect on the shield tunnel passing through buildings at close distance. © 2018, Editorial Department of Journal of Railway Engineering Society. All right reserved.     

汽车部件对污染的敏感性

污染敏感性分析是实现对整个机械系统污染控制的重要步骤。通过对污染的分析、测试、建模及模拟分析可有助于减少污染物或微小颗粒对机械系统造成的污染，避免因污染而导致的系统故障。对有关汽车机械系统污染的问题进行了分类讨论并进行了相关性分析，对测试及计算机建模方法进行了论述。给出了污染敏感性分析流程，最后通过几个典型实例阐明了污染敏感性分析的意义。     

Activity settings and travel behaviour: A social contact perspective

Using time-use data from Canada, Norway, and Sweden, this study briefly outlines the essence of the activity setting approach and illustrates one aspect of its usefulness by exploring the impact of social contact on travel behaviour. The activity system approach views behaviour in context. Activity settings are generic components of the activity system and studying them using time-use diaries can provide major insights into travel behaviour. Focusing on social contact, this paper characterizes the social environment in terms of social circle (interaction partners) and social space (location). The analysis shows that there are clear differences in the levels of social interaction across various groups, including those who work at home. The 1992 Canadian data showed people working at the workplace spend relatively more time with others, about 50% of total time awake. Working at home reduced the time with others to a low of 15.7%. when people worked at home the family benefited, almost doubling the time spent with them compared to those working at the workplace. Persons working at home only spend the most time alone. There is a tendency for persons with low social interaction to travel more. It is argued that individual need, or want, social contact and if they cannot find it at the workplace they will seek it elsewhere thus generating travel. Whether this is the result of need or opportunity is of minor relevance, what it does suggest is that working in isolation at home will not necessarily diminish travel but rather may simply change its purpose. This revised version was published online in June 2006 with corrections to the Cover Date.     

Integrated Environmental Modeling and Assessment of Coastal Ecosystems: Application for Aquaculture Management

This article presents an approach that couples coastal ecosystem modeling with integrated environmental assessment methodologies to support coastal management. The focus is to support the development of an ecosystem approach to aquaculture management including interactions with watershed substance loading. A Chinese bay, with intense aquaculture and multiple catchment uses, and where significant modeling efforts were undertaken is used as a case study. The ecosystem model developed for this bay is used to run scenarios that test the local management strategy for nutrient reduction. The corresponding ecological and economic impacts of the managers’ scenarios are analyzed by means of the Differential Drivers-Pressure-State-Impact-Response (ΔDPSIR) analysis. Emphasis is given to the analysis of the eutrophication process in the bay including present eutrophic condition and the expected changes due to the simulated scenarios. For this purpose, the Assessment of Estuarine Trophic Status (ASSETS) screening model is a valuable tool to interpret and classify the data and model outputs regarding eutrophication condition and to evaluate the manageable level of the nutrient loading entering in the bay.     

An evaluation of Councils on Aging dial-a-ride systems in Massachusetts

In many cities and towns in the Commonwealth of Massachusetts, Councils on Aging are running dial-a-ride services for elderly residents. A survey of these organizations was made to determine the service characteristics of their transportation systems. While the Council on Aging dial-a-rides do not achieve productivities as high as those achieved by public transit dial-a-rides, lower operating costs are achieved on a per hour basis. Thus the costs per passenger trip are very close to those for the public transit systems. The major advantage of the Council on Aging systems is their ability to employ volunteer or inexpensive labor. These systems are thus very attractive in areas with unused volunteer resources.     

Experimental study on liquefied petroleum gas fueled homogeneous charge compression ignition engine

International Journal of Automotive Technology - EGR (Exhaust Gas Recirculation) is one of the most effective techniques currently available for reducing NOx emissions from compression ignition...     

New energy recovery H∞ robust controller for electric bicycles

The electric controller is one of the most crucial components in an electric bicycle. The overall performance of the whole system heavily depends on the properties of the controller. The authors use the robust control theory to design a new H_∞ robust controller for the closed speed-current dual-loop driving and braking system. The designed controller also incorporates the driving and energy recovery braking circuit. Therefore, it has energy recovery ability, which coverts the kinetic energy wasted in braking into electric energy to recharge the battery. This prolongs the driving distance per battery charge. The simulations and experiments show that the new H_∞ robust controller out-performs the traditional PID controller in many respects including stability, error, responding speed and driving distance per battery charge.