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551.
In this feasibility study, we investigate the viability of using Liquefied Natural Gas (LNG) fuel in an open type Ro-Ro passenger ferry and the associated potential challenges with regard to the vessel safety systems. We recommend an appropriate methodology for converting existing ships to run on LNG fuel, discuss all the necessary modifications to the ship’s safety systems, and also evaluate the relevant ship evacuation procedures. We outline the basic requirements with which the ship already complies for each safety system and analyze the additional restrictions that must be taken into consideration for the use of LNG fuel. Appropriate actions are recommended. Furthermore, we carry out a hazard identification study. Overall, we clearly demonstrate the technical feasibility of the investigated scenario. Minimal modifications to the ship’s safety systems are required to comply with existing safety rules for this specific type of ship. 相似文献
552.
M. A. Hannan A. Hussain A. Mohamed S. A. Samad D. A. Wahab 《International Journal of Automotive Technology》2010,11(1):57-65
The need for an embedded system that can fuse incomplete, inconsistent, and imprecise decisions from several sensing systems
is a crucial step in achieving an effective decision for occupant safety measures. This paper deals with the decision fusion
strategies of a multi-sensing embedded system to achieve significant enhancement in the reliability of occupant safety through
the fused decisions. Multi-sensing approaches to determine weight, vision, and crash sensing are developed for occupant detection,
classification, position calculation, and crash detection. A rule-based decision fusion algorithm is then developed to fuse
the multi-sensing decisions. The developed sensing systems are incorporated into an embedded device. To execute the embedded
system, a system interface between the software and hardware is developed using Lab Window/CVI with the C programming language.
The experimental results demonstrated that the real time operation of the embedded system validate the effectiveness of the
decision fusion algorithm, characterize the safety measures and monitor the decision application. Several events were tested
that prove the performance of the embedded system is robust towards occupant safety measures. 相似文献
553.
S. J. Lee 《International Journal of Automotive Technology》2010,11(4):471-479
The analytical model of an air spring can be effectively used for the design of air spring equipped vehicles to provide better
ride and handling characteristics along with various functions for passenger convenience. However, establishing a general
model of an air spring poses particular difficulties due to the severe nonlinearities in the stiffness and the hysteresis
effects, which are hardly observed in conventional coil springs. The purpose of this study is to develop a general analytic
model of an air spring — one which represents the main characteristics of stiffness and hysteresis and which can be connected
to a model of pneumatic systems desigined to control air spring height. To this end, the mathematical model was established
on the basis of thermodynamics with the assumptions that the thermodynamic parameters do not vary with the position inside
the air spring, that the air has the ideal gas property, and that the kinetic and potential energies of the air are negligible.
The analysis of the model has revealed that the stiffness is affected by the volume variation, the heat transfer, and the
variation of the air mass and the effective area. However, the hysteresis is mainly affected by the heat transfer and the
variation of the effective area. In particular, it was revealed that the increase of the volume due to the cross-sectional
area increases the stiffness, while the increase of the volume due to the other reason decreases it. In addition, the model
was used to develop the sufficient stability condition, and the stability of the model was analyzed. The paper also presents
the comparison between the simulation and experimental results to validate the established model and demonstrates the potential
of the model to be usefully employed for the development of the air spring and its algorithm for use in a pneumatic system. 相似文献
554.
Hai Yang C.S. Fung K.I. Wong S.C. Wong 《Transportation Research Part A: Policy and Practice》2010,44(5):337-348
This paper examines the effects of nonlinear fare structures in taxi markets using an extended taxi model with an explicit consideration of perceived profitability. The expected profit, defined as the profit per unit time (inclusive of both occupied and vacant taxi times), that a taxi driver expects to receive from picking up a customer in a particular zone or location, has great impact on the taxi driver’s choice of location in the search for customers. The fare structure directly governs the profitability of taxi rides of different distances originating from different locations. With these explicit considerations, the extended model is intended to look into the market effects of adopting a nonlinear fare structure with declining incremental charges. The proposed nonlinear fare structure could help restore a level-playing field for taxi operators whose businesses have been affected by some taxi drivers who resort to practices such as offering fare discounts or accepting requests for discounted fares from passengers for long-haul trips. Analysis of sensitivity of social welfare and profit gain as well as taxi/customer wait/search times is conducted with respect to the parameters in the nonlinear fare structure for the Hong Kong taxi market, and Pareto-improving nonlinear fare amendments are identified that neither disadvantage any customer nor reduce the taxi operators’ profits. 相似文献
555.
M.F. Yáñez S. Raveau J. de D. Ortúzar 《Transportation Research Part A: Policy and Practice》2010,44(9):744-753
Travel demand models typically use mainly objective modal attributes as explanatory variables. Nevertheless, it has been well known for many years that attitudes and perceptions also influence users’ behaviour. The use of hybrid discrete choice models constitutes a good alternative to incorporate the effect of subjective factors. We estimated hybrid models in a short-survey panel context for data among many alternatives. The paper analyses the results of applying these models to a real urban case study, and also proposes an approach to forecasting using these models. Our results show that hybrid models are clearly superior to even highly flexible traditional models that ignore the effect of subjective attitudes and perceptions. 相似文献
556.
557.
This paper is concerned with the connection design for a two-floating beam system for minimum hydroelastic response. The frequency domain approach is used for the hydroelastic analysis. The fluid is modelled as an ideal fluid, and the floating beams are modelled by the Euler–Bernoulli beam theory. The boundary element method (BEM) and the finite element method (FEM) are applied to solve the governing equation of the fluid motion and the beam equation of motion, respectively. The study aims to investigate the optimum location and rotational stiffness of the connection for the two-floating beam system with the view to minimize the compliance. The study also investigates the effects of relative beam stiffnesses on the hydroelastic response of the two-floating beam system. 相似文献
558.
W. E. Misselhorn N. J. Theron P. S. Els 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2006,44(1):65-81
Hardware-in-the-loop (HiL) is a testing method in which real-time measurements on physical hardware replace the mathematical model of the particular hardware during simulation. The development of a semi-active suspension prompted the need for such capability. HiL, implemented on a PC with a dSpaceTM board in conjunction with a hydrodynamic actuator, was compared to software simulations of single degree of freedom (DOF) and two DOF systems. HiL was also compared to a physical (ballast-based) two DOF system, comprising the rear suspension of a motorcycle. Comparisons between the HiL and software responses showed its suitability for testing suspension systems, thus providing a viable alternative to ballast-based suspension tests, using available hardware. The research also showed that actuator dynamics, filter types and amounts, and signal reference levels required special consideration. 相似文献
559.
Z.L. Yang D. Zhang O. Caglayan I.D. Jenkinson S. Bonsall J. Wang M. Huang X.P. Yan 《Transportation Research Part D: Transport and Environment》2012,17(6):478-486
This paper develops a subjective generic methodology for providing ship owners with a transparent evaluation tool for selecting their preferred NOx and SOx control techniques. We quantitatively analyse the merits of the control methods available in marine air pollution control practice using data collected from shipping companies, shipyards and maritime academies. We also prioritize the applicable control techniques with respect to operational shipping environments. 相似文献
560.
Paul S. Szwed 《WMU Journal of Maritime Affairs》2011,10(2):183-208
Given the inherent complexity of the maritime transportation system, developing effective policy can be challenging. Using
risk factors identified by an elicitation and aggregation of expert judgment, a relative-risk rating scheme was developed
in the theory-building tradition of the social sciences. The model was empirically evaluated using 18 months of data from
the US small passenger vessel sector. The model identified that the top 10% of relatively highest risk vessels accounted for
50% of all marine casualties during the period of examination. A policy for deploying the model nationally is proposed. 相似文献