The development of safe riding guidelines for young riders – A case study of Phu Yen,Vietnam

Phu Yen is a small province located in the central part of Vietnam and is suffering from a tremendous number of traffic casualties, compared with other cities in Vietnam and developed countries. Young riders take a large proportion, accounting for 47.6% in total traffic crashes. To resolve this issue, the present study aims to (i) analyze young riders' behavior and their attitudes towards traffic safety and to (ii) propose a procedure to develop a book of safe riding guidelines to reduce their involvement in dangerous situations. A set of 73 questions in the questionnaire survey have been conducted to determine the risk-taking behavior and attitude towards traffic safety of 300 individuals, who are using bicycles, e-bikes, mopeds, scooters, and motorcycles less than 150 cc. The statistical results indicate that there are significant differences among riding behavior and attitudes of respondents towards traffic safety regarding the regional factor (rural, suburb, and urban), the demographic factor (gender and age), and the travel distance factor. The guidelines designed based on the questionnaire survey are used to alter adolescents' riding behavior and attitudes and so help them recognize, avoid, and handle risks in demanding traffic situations. An analysis of the before and after the traffic safety training workshop to evaluate the effectiveness of the proposed guidelines indicated that there was a significant increment in the perceived risks of young riders after training them by using this book.     

Crosswind Feedforward Control - A Measure to Improve Vehicle Crosswind Behaviour

The theory of crosswind feedforward control was explained using the example of a vehicle with active front-wheel steering. Beforehand, the calculation formulas and frequency responses of the transient crosswind force and of the wind yaw moment acting on the vehicle were derived using the example of a simple vehicle fluid model. The influence of the transiency of crosswind disturbance on the dynamic crosswind behaviour of a vehicle was then presented. The results of simulation confirmed the analyses carried out in the frequency domain for feedforward control with front, rear and all-wheel steering. With front-wheel steering, the influence of crosswind on one of the vehicle movement variables (lateral acceleration or yaw rate) could be almost completely compensated by dynamic feedforward control. With rear-wheel steering, it is only possible to compensate directly for the influence on the yawing rate. Due to the setting of the side force in the same direction as the lateral wind force at the start, active rear-wheel steering is not so successful as active front-wheel steering. Nevertheless, the crosswind behaviour of a vehicle can be considerably enhanced by feedforward control with rear-wheel steering. The best crosswind behaviour was obtained with active all-wheel steering: the vehicle hardly responds at all to crosswinds and remains on course despite heavy gusts of wind.     

Applications of a new ecosystem model to study the dynamics of phytoplankton and nutrients in the Ariake Sea,west coast of Kyushu,Japan

In this study, we present the development and application of a new ecosystem model coupled with a hydrodynamic model to describe the important physical, chemical and biological processes of an ecosystem in the marine environment, the Ariake Sea in the west coast of Kyushu, Japan. The model was calibrated and validated using in-situ field measurements from various monitoring stations in the sea. The presented results covered the period from January 1991 to December 2000. The results showed that chlorophyll-a, nutrients and dissolved oxygen levels varied seasonally in response to weather and boundary condition. Through this study, the model was shown to be able to handle the flooding and drying processes that usually exist and play an essential role over the estuarine-tidal flats of the sea.     

Urban travel demand: The impact of Box-Cox transformations with nonspherical residual errors

We develop an algorithm for solving regression models with Box-Cox transformations on both the dependent and independent variables, while simultaneously taking into account corrections for serial correlation of several orders and for heteroscedasticity. The latter correction is of a general form which contains as special cases most specifications of heteroscedasticity found in practice. We apply the procedure to three urban travel demand functions, two of which are currently used in their linear form by the Montreal Transit Authority, and analyze more than 100 specifications. Our results show that taking into account nonsphericalness of the residuals has a major impact on model parameter estimates, notably on those which determine the functional form of the model, and that, conversely, modifications of the functional form have strong implications for both the structure of autocorrelation and the importance of heteroscedasticity; moreover, we find interactions between autocorrelation and heteroscedasticity structures. We introduce a special measure of elasticity for variables which contain zero observations, particularly dummy variables. Moreover, we find that elasticities of demand and implicit values of time depend to a large extent on the stochastic specification of the model.     

Automatic control of clutches and simulations for parallel hybrid vehicles

This paper is a continuation of a previous paper titled ??Modeling and Model Predictive Control for Hybrid Vehicle?? published on IJAT/2011 describing a mathematical model and design for a model predictive controller for tracking speeds and simulations. The present paper further describes a fuzzy logic controller for the smooth and quick engagement of an automatic clutch. The described controller uses both fuzzy logic and slip control algorithms to enable automatic clutch engagement. Clutch engagement and comprehensive simulations for the hybrid vehicle are conducted in MATLAB R2009s. The research described herein offers theoretical solutions for how to better control clutch slip and engagement within realistic parameters used for hybrid vehicles. Algorithms and operations of this fuzzy logic controller can be implemented in electronic control units for automatic clutch engagements and gear-shifting processes.     

越南海防城市交通现状分析及改善策略

在交通运输方面,海防港是越南北方进出口货物的中转站,海防市是越南的北方交通枢纽,与外省市交通联系有重要的位置。近年来,随着经济的迅速发展,海防市的交通矛盾日益突出．本文通过对海防市城市交通现状进行分析,找出其目前存在的主要问题,即路网密度低,基础设施条件差,居民出行以自行车、摩托车为主,公共交通为辅,进而提出发展海防市城市交通的相应对策。     

Factors influencing home-based telework in Hanoi (Vietnam) during and after the COVID-19 era

Transportation - During the era of COVID-19 (COronaVIrus Disease of 2019), telework has been adopted extensively in developing countries for the first time. This study analyzes data of 355...     

Long-term behavior of particulate matters at urban roadside and background locations in Seoul,Korea

The concentrations of particulate matter, PM_2.5, PM₁₀, and TSP at an urban roadside and an urban background station are analyzed. Data collected over a 10 year period are analyzed. The concentrations of the particulates measured at the urban site are systematically larger than at the background station. The mean PM values at the former also exhibit a slight fall over the decade unlike those at the background station. Overall, the particulate matters at both locations are in an intermediate range of global level, e.g., approximately two times lower than those in other Asian regions but higher than in Europe.     

Empirical Equilibrium Beach Profiles Along the Eastern Tombolo of Giens

Beaches along the eastern branch of the Giens double tombolo are subject to coastal erosion. Prediction of the behavior of the beach profile configuration in response to natural and anthropogenic changes using the concept of equilibrium beach profile (EBP) could be useful in finding the most suitable measure to address the erosion problem. Field investigation data of 11 beaches along the eastern tombolo were supplied for this study, and a nonlinear fitting technique was applied to estimate the best parameter values of seven empirical formulations of the relevant EBP. All of the observed beach profiles could be described by a single function, but a single EBP was inadequate to represent all of the beach profiles observed. The variation found could be explained in terms of longshore variation of bathymetry, sediment size, and wave parameters. Analysis of the validity of the EBPs revealed that a representative EBP of each beach is governed by different equilibrium parameters.     

法国日安东连岛沙洲沿岸海滩剖面经验平衡（英文）

Beaches along the eastern branch of the Giens double tombolo are subject to coastal erosion. Prediction of the behavior of the beach profile configuration in response to natural and anthropogenic changes using the concept of equilibrium beach profile(EBP) could be useful in finding the most suitable measure to address the erosion problem. Field investigation data of 11 beaches along the eastern tombolo were supplied for this study, and a nonlinear fitting technique was applied to estimate the best parameter values of seven empirical formulations of the relevant EBP. All of the observed beach profiles could be described by a single function, but a single EBP was inadequate to represent all of the beach profiles observed. The variation found could be explained in terms of longshore variation of bathymetry, sediment size, and wave parameters. Analysis of the validity of the EBPs revealed that a representative EBP of each beach is governed by different equilibrium parameters.