Rapid transit system simulation with interactive graphics display

A mathematical model of a rapid transit system has been developed. The model employs computer techniques to simulate the physical system. To further enhance the results and gain management confidence in the reliability and validity of the design of the model, a TV‐like display of the computer results enables the viewer to “see” the performance of the model as it happens. The results displayed thus include: The track layout, time (simulation), train position on the track, and the number of passengers riding on each train and waiting at each platform or station. The computer printout of results is limited to summary type data, relying on the display for detailed evaluation and analysis.     

Patterns of urbanization and energy requirements: recent regulation changes and simulation studies concerning American urban areas

In recent years, the world economy has become more integrated internationally and container transportation has become increasingly more important as the proportion of all trade using containers is continuously growing. In order to adapt to the increasing containerization trend, it is essential to plan and construct adequate ports and facilities to cope with this development.

Based on the analysis of factors influencing container movements, this paper illustrates the logical relationships for a distribution model, which has been used to predict the distribution of containers among the three main Seaports near Shenzhen and Hong Kong. A fuzzy number‐based distribution model is outlined in the paper. The paper illustrates the main influencing factors and their logical relationships and proposes a primary distribution model where the attractiveness of each port has been calibrated. The results show that the Port of Hong Kong is significantly more attractive than the other two ports modelled and is likely to continue to be so in the future.     

Fisheries–Marine Protected Area–Tourism Interactions in Moalboal,Cebu, Philippines

The development of Integrated Coastal Management (ICM) in the Philippines has been underway for more than 30 years. As coastal communities continue to face dwindling resources from both the land and sea, marine protected areas (MPAs) have been regularly utilized as a community-based marine conservation tool. Recently, marine tourism has begun to exert influence as a driver utilized by local communities to promote the establishment of MPAs. Revenue generated through user-fee systems has begun to influence and shape broker–local–tourist (BLT) interactions in Moalboal, Cebu, Philippines. In this article, an account of the social dynamics surrounding MPAs is presented, sources of tension are identified, and recommendations proposed.     

Simplified p-norm-like constraint LMS algorithm for efficient estimation of underwater acoustic channels

Underwater acoustic channels are recognized for being one of the most difficult propagation media due to considerable difficulties such as: multipath, ambient noise, time-frequency selective fading. The exploitation of sparsity contained in underwater acoustic channels provides a potential solution to improve the performance of underwater acoustic channel estimation. Compared with the classic l ₀ and l ₁ norm constraint LMS algorithms, the p-norm-like (l _p ) constraint LMS algorithm proposed in our previous investigation exhibits better sparsity exploitation performance at the presence of channel variations, as it enables the adaptability to the sparseness by tuning of p parameter. However, the decimal exponential calculation associated with the p-norm-like constraint LMS algorithm poses considerable limitations in practical application. In this paper, a simplified variant of the p-norm-like constraint LMS was proposed with the employment of Newton iteration method to approximate the decimal exponential calculation. Numerical simulations and the experimental results obtained in physical shallow water channels demonstrate the effectiveness of the proposed method compared to traditional norm constraint LMS algorithms.     

The modelling of dry bulk and tanker markets: a survey

This paper provides an overview of the development of the quantitative modelling techniques that have been applied to the analysis of dry bulk shipping markets. Of necessity it will be dated by the time it is published. The principal points that emerge from the survey are fourfold: first:-reduced form rather than structural modelling, has become the standard approach in the past 15 years. Second, there is a greater focus on modelling rate variability rather than rate levels, using models that estimate the behaviour of both the conditional mean freight rate and its conditional variance. Third, the introduction of models of financial derivatives and their application to shipping markets has been very marked, as finance models of risk management have been adapted to shipping markets. Fourth, the use of segmented models of different ship types, and higher frequency data is now standard. It is argued that the relative neglect of structural models means that estimating fully specified structural econometric models may be a fruitful research agenda for the future.     

Coordination mechanisms in improving hinterland accessibility: empirical analysis in the port of Rotterdam

Hinterland accessibility is one of the main determinants in port competition. Improving hinterland accessibility is a complex process in which many actors are involved and many factors play a role. It requires coordination mechanisms beyond the price mechanism; conditions of complexity can become such that assistance is needed from other coordination mechanisms, such as introduction of incentives, creation of an interfirm alliance, changing scope, and creating collective action. The goal of this paper is to gain a better understanding on coordination in hinterland chains. Based on the insights of Transaction Cost Economics, a set of variables is explicated in order to understand when, by whom, and under which conditions and situations coordination arrangements are chosen. The variables can be divided into variables related to the complexity of the coordination problem and variables related to the coordination arrangement. The variables are used in an empirical analysis of coordination arrangements in hinterland transport from and to the port of Rotterdam. This analysis provides insight into the patterns and conditions of the emergence of different coordination arrangements that improve hinterland accessibility.     

2 kHz high power smart transducer for acoustic sub-bottom profiling applications

In this study,a 2kHz Tonpilz projector was designed using a Terfenol-D and modeled in ATILA.For the purpose of modeling studies,it has been determined that a radiating head mass exhibits better transmitting current response（TCR） at 136 mm diameter,where the resonance occurs at 2.4kHz and the peak value of 118 dB re 1 μPa/A at 1 m occurs at 12 kHz.Also bolt at a 46mm distance from the center of the head mass offers resonance at 2.4kHz,and the peak value of 115.3 dB re 1 μPa/A at 1m occurs at 11.5kHz.This optimized design is fabricated and molded with polyurethane of 3mm thickness.The prototype was tested at the Acoustic Test Facility（ATF） of National Institute of Ocean Technology（NIOT） for its underwater performances.Based on the result,the fundamental resonance was determined to be 2.18kHz and the peak value of TCR of 182 dB re 1 μPa/A at 1m occurs at 14 kHz.The maximum value of the RS was found to be -190 dB re 1V/μPa at 1m at a frequency of 2.1kHz.     

船舶SOFC燃料电池与汽轮机联合动力装置能效分析(英文)

Strong restrictions on emissions from marine power plants(particularly SOx,NOx)will probably be adopted in the near future.In this paper,a combined solid oxide fuel cell(SOFC)and steam turbine fuelled by natural gas is proposed as an attractive option to limit the environmental impact of the marine sector.The analyzed variant of the combined cycle includes a SOFC operated with natural gas fuel and a steam turbine with a single-pressure waste heat boiler.The calculations were performed for two types of tubular and planar SOFCs,each with an output power of 18 MW.This paper includes a detailed energy analysis of the combined system.Mass and energy balances are performed not only for the whole plant but also for each component in order to evaluate the thermal efficiency of the combined cycle.In addition,the effects of using natural gas as a fuel on the fuel cell voltage and performance are investigated.It has been found that a high overall efficiency approaching 60%may be achieved with an optimum configuration using the SOFC system.The hybrid system would also reduce emissions,fuel consumption,and improve the total system efficiency.     

Yaw rate and side-slip control considering vehicle longitudinal dynamics

Most conventional vehicle stability controllers operate on the basis of many simplifying assumptions, such as a small steering wheel angle, constant longitudinal velocity and a small side-slip angle. This paper presents a new approach for controlling the yaw rate and side-slip of a vehicle without neglecting its longitudinal dynamics and without making simplifying assumptions about its motion. A sliding-mode controller is used to develop a differential braking controller for tracking a desired vehicle yaw rate for a given steering wheel angle, while keeping the vehicle’s side-slip angle as small as possible. The trade-off that exists between yaw rate and side-slip control is described. Conventional and proposed algorithms are presented, and the effectiveness of the proposed controller is investigated using a seven-degree-of-freedom vehicle dynamics model. The simulation results demonstrate that the proposed controller is more effective than the conventional one.     

中国城市轨道交通未来十年发展趋势及政策导向

分析了我国城市轨道交通的发展现状、特点和问题.结合城市轨道交通的发展趋势,探讨了发展过程中的政策缺陷.从综合性、公交优先、国产化、标准化、市场化以及一体化等方面提出了发展我国城市轨道交通的导向政策.