Drivers' route choice and learning mechanism under bounded information environment

In this paper, we propose the theory of Rational Beliefs as the model of expectations that extends the theory of rational expectations to the postulated environments. Under the rational beliefs paradigm, drivers do not have structural knowledge of traffic conditions and they choose their routes based only on personal experiences and decision‐making rules. We found that if drivers have different decision‐making rules and experiences, then they form different beliefs of traffic conditions (e.g. average travel time) even though they have the same public information and use the same routes. Under the rational beliefs model, drivers are not motivated to renew their beliefs because the beliefs are compatible with their experiences. Therefore, the heterogeneity of beliefs does not disappear even though they have long‐term learning. In order to investigate how drivers form their beliefs of traffic conditions under bounded information environments, numerical experiment is carried out.     

叉车液压转向系统的改造

在现代港口中,叉车数量多.应用广,是装卸机械的主力.叉车的转向系统直接影响到叉车使用的灵活性和安全性.     

Method to simplify ship outfitting and offshore plant equipment three-dimensional (3-D) computer-aided design (CAD) data for construction of an equipment catalog

The construction of an equipment catalog is necessary in ship outfitting and offshore plant design. We investigated the present status of equipment catalogs in shipyards and revealed several requirements for the catalogs, which are manually created and time-consuming. We defined the requirements by analyzing the construction procedure of the equipment catalog and conducted interviews with shipyard employees. In addition, problems with conventional equipment catalog construction are described, and a new procedure for the construction of an equipment catalog is introduced. By analyzing shipyard requirements, criteria for simplification (including volume, ports, and the outer boundary) are defined. Further analysis of technological factors for simplification is performed, and the results of implementing the simplification system are described. The proposed system is verified using three test cases used on site.     

A structural equation model of activity participation and travel behavior using longitudinal data

Abstract

This paper presents a dynamic structural equation model (SEM) that explicitly addresses complicated causal relationships among socio-demographics, activity participation, and travel behavior. The model assumes that activity participation and travel patterns in the current year are affected by those in previous years. Using the longitudinal dataset collected from Puget sound transportation panel ‘wave 3’ and ‘wave 4,’ these assumptions are tested with suggested SEMs. Within each wave, the model is structured to have a three-level causal relationship that describes interactions among endogenous variables under time-budget constraints. The resulting coefficients representing the activity durations indicate that people tend to allocate their time according to the importance and the obligation of the activity level. Results from the dynamic SEM confirm the fact that people's current activity and travel behavior do have effects on those in the future. The resulting model also shows that activity participation and travel behavior in ‘wave 3’ are closely related to those in ‘wave 4.’ These explicit explanations of relationships among variables could provide important perspectives in the activity-based approach which becomes recognized as a better analytical tool for the transportation planning and policy making process.     

耦合非线性三维海洋立管的边界控制(英文)

This paper presents a design of boundary controllers implemented at the top end for global stabilization of a marine riser in a three dimensional space under environmental loadings. Based on the energy approach, nonlinear partial differential equations of motion, including bending-bending and longitudinal-bending couplings for the risers are derived. The couplings cause mutual effects between the three independent directions in the riser’s motions, and make it difficult to minimize its vibrations. The Lyapunov direct method is employed to design the boundary controller. It is shown that the proposed boundary controllers can effectively reduce the riser’s vibration. Stability analysis of the closed-loop system is performed using the Lyapunov direct method. Numerical simulations illustrate the results.     

Effect of various LPG supply systems on exhaust particle emission in spark-ignited combustion engine

The particle size distribution and particle number (PN) concentration emitted by internal combustion engine are a subject of significant environmental concern because of their adverse health effects and environmental impact. This subject has recently attracted the attention of the Particle Measurement Programme (PMP). In 2007, the UN-ECE GRPE PMP proposed a new method to measure particle emissions in the diluted exhaust of automotive engines and a regulation limit (<6.0×10¹¹ #/km, number of particles). The specific PN regulation of spark-ignited combustion engine will be regulated starting on September 1, 2014 (EURO 6). In this study, three types of LPG supply systems (a mixer system and a multi-point injection system with gas-phase or liquid-phase LPG fuel) were used for a comparison of the particulate emission characteristics, including the nano-sized particle number density. Each of the three LPG vehicles with various LPG injection systems contained a multi-cylinder engine with same displacement volumes of 2,000 cm³ and a three-way catalytic converter. The test fuel that was used in this study for the spark-ignited combustion engine was n-butane basis LPG fuel, which is primarily used for taxi vehicles in Korea. The characteristics of nano-particle size distribution and number concentration of particle sizes ranging from 20 to 1,000 nm (aerodynamic diameter) that were emitted from the three LPG vehicles with various LPG supply systems were investigated by using a condensation particle counter (CPC), which is recommended by the PMP under both the NEDC and FTP-75 test modes on a chassis dynamometer. The experimental results indicate that the PN emission characteristics that were obtained by the CPC system using the PMP procedure are sufficiently reliable compared to other regulated emissions. Additionally, the sources of PN emissions in ascending order of magnitude are as follows: mixer type, gas-phase LPG injection (LPGi) and liquid-phase LPG injection (LPLi) passenger vehicles. The liquid-phase LPG injection system produced relatively large particle sizes and number concentrations compared to the gaseous system, regardless of the vehicle driving cycle. This phenomenon can be explained by unburned micro-fuel droplets that were generated due to a relatively short homogeneous fuel-air mixture duration in the engine intake manifold. Also the particle number emissions from the LPG vehicle were influenced by the vehicle driving cycle.     

Emissions simulation in a 7000 kg-grade diesel hybrid electric vehicle

Hybrids combine a combustion engine with an electric motor and battery. The two technologies can be combined to reduce fuel consumption and exhaust emissions. This paper presents the concept of hybrid electric vehicles (HEVs) applied to truck or van vehicles with diesel engines. The simulation results from the advanced vehicle simulator (ADVISOR) demonstrate that the required power may be properly shared between the internal combustion engine and electric motor. The simulation can also be used to prove that the technique is useful for improvements in driving performance; additionally, the technique is suitable for hybrid electric vehicles, allowing for good fuel economy and low emissions performance.     

Characterization of driving patterns and development of a driving cycle in a military area

This study develops a gradient-sensitive driving cycle for vehicles in military areas with paved and unpaved roads over steep and undulating terrain. The methodology develops the driving cycle using micro-trips extracted from real-world data taking into account factors that affect fuel consumption. The accuracy of cycle depended on the root mean square error and information value.     

Exposure of urban populations to road traffic noise in Hong Kong

This article examines the exposure of Hong Kong’s population to road traffic noise and whether there is class-biased inequality in this. The socio-economic characteristics of residents of public and private building are taken from census data and the noise exposure levels from 3-D noise mapping. Using decile plots and binary logistic regression analysis, we find that in general the socially deprived groups tend to live in building groups exposed to higher noise levels. This is particularly pronounced in private housing estates where older, less educated, those engaged in craftsman and elementary jobs, and non-owners of their dwellings are exposing to higher levels of traffic noise. Inequality is less conspicuous in public housing estates.