Fuzzy and adaptive fuzzy control for the automobiles' active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

Approximate Dynamic Shimmy Response of Pneumatic Tires*

An improved approximation of the theory of the dynamic frequency response of side force and aligning torque acting upon the rolling wheel when the latter is moved laterally and swivelled about the vertical axis, is presented. The method is particularly suitable for application in vibration problems of steering and suspension systems of automobiles and aircraft where relatively high speed and high frequency phenomena play a role. The theoretical results show satisfactory agreement with experimental data. Calculations indicate that the inertia of the tire decreases the tendency to shimmy at higher frequencies and speeds of travel. For castered wheels however, tire inertia may have an adverse effect due to its unfavorable influence upon the side force response to swivel motions.     

罐车牵引梁失效容限分析全尺寸验证试验

介绍了用铁道车辆的全尺寸多轴液压伺服台－－模拟加载器，以及建立在裂纹分析方法基础上的失效容限分析，并以北美铁路摧车工业所承担的罐车牵引梁研究项目为例，采用模拟加载器来验证失效容限分析。     

Seasonal phytoplankton responses to environmental factors in a shallow Mediterranean lagoon

Phytoplankton community structure was investigated in a 1-year study period from January to December 2006 in the Tunis North Lagoon (South Mediterranean). Twice a month, sampling was carried out from the whole water column. Phytoplankton species composition showed seasonal dynamics following the general environmental variable trends in the study area, with variation in species abundance levels within each season characterised by the presence of different phytoplankton communities. Analysis of environmental variables indicated that phytoplankton-dominant communities were associated with various water physicochemical characteristics, especially water temperature and salinity. Accordingly, significant correlation was recorded between water temperature and dinoflagellates (r = 0.35; p < 0.05) in summer and diatoms (r = 0.69; p < 0.05) in autumn, whereas euglenophytes, cyanophytes and chlorophytes were slightly correlated with temperature in autumn. Salinity was positively correlated with dichtyophytes (r = 0.41; p < 0.05) in winter and with diatoms (r = 0.65; p < 0.05) and euglenophytes (r = 0.57; p < 0.05) in autumn. On the other hand, relationships between high nitrogen nutrient concentration and phytoplankton concentration were recorded for diatoms (r = 0.43; p < 0.05 with NO₂; r = 0.49; p < 0.05 with NO₃) in winter. Silicate concentration supported proliferation of diatoms (r = 0.58; p < 0.05) in autumn in our study period. In contrast, increase of dinoflagellate concentration was associated with the decrease of these parameters in spring and summer.     

Evaluating the impacts of shared automated mobility on-demand services: an activity-based accessibility approach

Transportation - Autonomous vehicle (AV) technologies are under constant improvement with pilot programs now underway in several urban areas worldwide. Modeling and field-testing efforts are...     

Analysis of airline operating strategies under stochastic demand

Variability in the demand for air travel is studied with respect to stochastic and time varying components which affect the distribution of passengers who will want to travel on a particular day. The problem is then cast as one of optimizing the total capacity offered in a given time period using operating net revenues as the objective. The distribution of demand is assumed to be normal, and passengers lost on those days when demand is high are assumed to travel on another airline or a different mode. An airline must therefore balance the costs of increased capacity against the benefits of carrying more people. Tradeoffs are studied parametrically, with particular emphasis on the effect the variance of the distribution of demand has on different relationships. Also shown is a simple procedure for estimating actual market mean and variance given the mean and variance of the number of passengers actually flown, which has a truncated distribution.     

Seamen, drink and social structure

Drinking among seafarers is an age-old and insufficiently studied problem. This paper is not concerned with alcoholism but with normal social drinking, its effects on suicide and accident rates, and its considerable value as an integrating factor in shipboard life. The author distinguishes sharply between sea-drinking and port-drinking and summarizes the research that relates personality traits, particularly dependence, to the use and abuse of alcohol.     

Transportation benefits from containerized cargo movements on the Trinity River, Texas

The future of waterborne commerce on the Trinity River, Texas, depends on the extent to which the waterborne transport system constitutes a definite cost saving over alternate transportation modes. This paper outlines the results of a study conducted in the area, the purpose of which was to establish potential transportation savings from containerized commodity movements on the Trinity River.     

隧道衬砌结构可靠指标计算方法的研究

本文采用有限元－响应面法及Ｍｏｎｔｅ－Ｃａｒｌｏ模拟获得衬砌结构内力的特征参数，并以此为基础，利用五种结构可靠度分析法计算明洞与隧道衬砌结构可靠指标，经对比得出Ｔｒｙｍ法求出的隧道衬砌结构可靠指标最小，为今后进一步寻求隧道结构设计安全系数与可靠指标之间的对应关系奠定基础。