Objective evaluation of door-closing sound quality based on physiological acoustics

This paper presents a new method to objectively quantify the sound quality of doors closing in premium passenger cars. In previous works, psychoacoustic parameters have been used for objective quantification. However, these parameters do not agree well with subsequent subjective assessments. Therefore, the correlation between the psychoacoustic parameters and the subjective rating of door closing sounds in sampled cars is low, and it is not sufficient to use psychoacoustic parameters as an objective metric to quantify the quality of door-closing sounds. In this paper, a new method is proposed to objectively quantify the sound quality based on physiological acoustics and statistical signal processing. A gammatone filter is used as a pre-processing method in models of the auditory system and kurtosis, which is the fourth-order moment of the temporal signal and is used to extract quantitative information about the quality of door-closing sounds. The new metric obtained from the proposed method is highly correlated to subjective ratings and has been successfully applied to the quantification of door-closing sound quality.     

Effect of punch angle on energy absorbing characteristics of tube-type crash elements

As a crash energy absorber, a tube-type crash element (expansion tube) dissipates kinetic energy through the internal deformation energy of the tube and through frictional energy. In this paper, the effects of the variation of punch angles on the energy-absorbing characteristics of expansion tubes were studied by quasi-static tests using three punch angles (15°, 30°, and 45°). A finite element analysis of the tube expanding process (m = τ _max /K) was performed using a shear friction model to confirm the variation of the shear friction factor with respect to punch angles using the inverse method. Additional analyses were performed using angles of 20°, 25°, 35°, and 40° to study the effect of the punch angles on the internal deformation energy, frictional energy, and expansion ratio of the tubes. The results of the experiment and finite element analysis showed that the shear friction factor was inversely proportional to the punch angles, and a specific punch angle existed at which the absorbed energy and expansion ratio remained constant.     

Inclusion of latent variables in Mixed Logit models: Modelling and forecasting

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.     

Numerical evaluation method of lightning rod protection probability北大核心CSCD

［Objectives］Aiming at the current situation in which it is difficult to efficiently evaluate protection probability through traditional lightning rod evaluation methods, an efficient numerical evaluation algorithm is developed on the basis of an electrogeometric model (EGM) and attractive volume to realize the efficient calculation of lightning protection probability at any point in space.［Methods］This method first determines the attractive volume boundary of the lightning rod and protection object according to the interception process of the upward and downward leaders. The collection surface and exposure arc of the lightning stroke distance are then calculated, enabling the attractive risk and interception effect of the lightning rod to be quantified. Finally, the attraction and interception characteristics of the lightning rod are integrated to establish a numerical evaluation model of protection probability. To verify the accuracy of this method, the general rule of lightning rod protection probability is analyzed and the results compared with the existing analysis method.［Result］The evaluation results of this method show good agreement with those of classical leader progression model (LPM) theory.［Conclusions］ The method proposed herein has a high degree of quantification and can realize the efficient calculation of lightning protection probability at any point in space, which can provide useful references for lightning protection design work. © 2023 Authors. All rights reserved.     

Influence of external restraint distribution on welding buckling of thin plate butt joint北大核心CSCD

［Objectives］It is easy to produce buckling distortion when welding thin plate butt joints, which affects the construction period, cost and performance, but this can be controlled by applying external restraints. ［Methods ］ First, a butt welding test of a thin plate under external restraints is carried out, and the out-of-plane deformation is measured by the optical surface scanning method. At the same time, finite element (FE) models in a free state and external restraint state are established, and the thermal mechanical phenomena of the two models are subjected to thermal-elastic-plastic FE analysis (TEP FE). The influence of different external restraint distributions on the welding buckling distortion of the joints is then studied, and reasons for controlling welding buckling distortion are analyzed from the perspective of longitudinal plastic strain and longitudinal contraction force.［Results ］ The out-of-plane deformation of the corresponding model is in good agreement with the measured results, and milder than the out-of-plane deformation of the model in a free state. When external restraints are applied, the longitudinal plastic strain of the weld and its adjacent metal decreases, and the longitudinal contraction force of the thin plate also decreases.［Conclusions ］ The results verify that external restraints can effectively control welding buckling distortion, and the control effects are different depending on the external restraint distribution. © 2023 Chinese Journal of Ship Research. All rights reserved.     

Analysis of ultimate uniaxial compressive strength of stiffened panel considering influence of shear load北大核心CSCD

［Objective］This study aims to explore the law of the critical compression stress of stiffened panels under the influence of in-plane shear load, and whether in-plane shear load combined with lateral pressure will introduce a strong coupling effect. ［Method ］ To this end, nonlinear finite element (FE) software ABAQUS is used to perform numerical simulation analysis under combined loads on a group of FE models. A limit state equation/curve is then derived from the dimensionless calculation results based on the minimum square error method. ［Results］The results show that the influence law of in-plane shear load on the critical compression stress of stiffened panels is clarified, and a limit state equation of stiffened panels that considers the effect of shear load is obtained. ［Conclusion］The limit state equation in this paper can provide references for modifying the ultimate strength of stiffened panels under the influence of in-plane shear load. © 2023 Chinese Journal of Ship Research. All rights reserved.     

A computerized household activity scheduling survey

Household activity scheduling is widely regarded as the underlying mechanism through which people respond to emerging travel demand management policies. Despite this, very little fundamental research has been conducted into the underlying scheduling process to improve our understanding and ability forecast travel. The experimental survey approach presented in this paper attempts to fill this gap. At the core of the survey is a Computerized Household Activity Scheduling (CHASE) software program. The program is unique in that it runs for a week long period during which time all adult household members login daily to record their scheduling decisions as they occur over time. An up-front interview is used to define a household's activity agenda and mode availability. A sample of 41 households (66 adults and 14 children) was used to assess the performance of the survey. Analysis focuses on times to completion, daily scheduling steps, activity-travel patterns, and scheduling time horizons. Overall, the results show that the computer-based survey design was successful in gathering an array of information on the underlying process, while minimizing the burden on respondents. The survey was also capable of tracing traditionally observed activity-travel outcomes over a multi-day period with minimal fatigue effects. The paper concludes with a detailed discussion on future survey design, including issues of instrument bias, use of the Internet, and improved tracing of spatial behaviour. Future use of the survey methodology to enhance activity-travel diary surveys and stated responses experiments is also discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

A real-time multi-vehicle simulator for longitudinal controller design

This paper presents a new multi-vehicle simulator for platoon simulation. The main new feature of the developed simulator is a network structure for the real-time simulation of multiple vehicles, each with a detailed powertrain and engine model. It has a small initial delay, which is determined by the number of connected PCs, but the actual simulation is performed and displayed in real-time after this initial and one-time delay. Several longitudinal controllers, including a PID controller with gain scheduling, an adaptive controller, and a fuzzy controller, are also implemented in the simulator. Various system parameters can be modified interactively in the simulator screen, which is very useful for simulating a platoon of heterogeneous vehicles, in which vehicles with different dynamics and different longitudinal controllers may be involved. The simulator provides an excellent tool to develop vehicle longitudinal controllers and to study platoon behaviors. The developed simulator is also effective in testing the effects of nonlinearities neglected in the controller design phase, such as actuator delays and gear shifting schedule.     

Distribution and diet of larval and juvenile Arctic cod (Boreogadus saida) in the shallow Canadian Beaufort Sea

The distribution and diet of larval and juvenile Arctic cod (Boreogadus saida) were studied during summer 2005 in the coastal Canadian Beaufort Sea. A total of 275 individuals were captured and the highest abundance was observed at station depths of 20–30 m. This corresponds well with the location of the frontal zone where the Mackenzie River plume water and open sea water meet. Diet examinations were performed on 220 Arctic cod, which were found undamaged from sampling. We observed a gradual decrease in prey number per fish and increase in prey size as larvae grew which corresponded to a shift from Rotifera and nauplii towards larger copepodid stages. However, at all sizes, the larvae remain generalists and feed on a broad range of organisms. Environmental changes due to climate warming could have a two-fold impact on fish larvae feeding in the studied region. First, the potential for increased primary production may lead to increased zooplankton production that may impact the feeding and nutrition positively. On the other hand, greater discharge of turbid water from the Mackenzie River may reduce light penetration in the water column that may negatively influence the ability of visual predators to successively forage.     

EFFECTS OF NITRIC OXIDE SYNTHESIS INHIBITION WITH OR WITHOUT NITRIC OXIDE IN

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