Level of public transport service evaluation: A fuzzy set approach

The success of any enterprise, in a market-oriented economy, depends upon it's quality. This paper describes the results of a survey of commuters on the quality of services and their relative weights, and of the attributes that determine the service level of bus transport undertakings. The model uses the theory of fuzzy sets to process the information obtained. A composite index, called level-of-public transport-service (LOPTS), is defined and used to measure the service qualities. This approach is presented with guidelines for rating the quality of services, fuzzy-set representations of the linguistic grades, definition of LOPTS and its use in a public transport quality data base. An example is presents how the approach can be employed to analyse data bases generated from a quality survey. This approach is compared with the numerical rating approach with single number representation.     

Full scale measurements at magnus

The environmental and structural monitoring system on Magnus tower was designed making use of experience from previous monitoring systems on West Sole, Forties and Buchan. The paper describes the measuring systems adopted together with their calibration procedures and independent checks.

The major results in terms of environmental conditions and platform response are discussed. They are compared with the Forties results and standard design procedures. Deterministic and spectral extreme conditions are considered. Where applicable, comparisons are made with other published results.

Finally, the principal conclusions of the measurement programme are presented and discussed. These refer particularly to structural dynamics, coefficients for the Morison equation and appropriate methods of application of wave loading to a deep water structure.     

Analysis of the Stability of Braking Systems in Car and Caravan Combination

In the present article, a mathematical model of the car-caravan combination has been constructed. In simulating the transmission of forces in the articulation of the joint, special attention has been focussed on two types of action in the braking system of the caravan: the conventional braking through overrun and a prototype with hydraulic action. The model of the articulation has been compared with tests carried out on a real vehicle. This model has been constructed by means of a computer programme with different braking maneuvers with the view to analyse the influence of one system or the other on the general behaviour of the vehicle.     

MTU396系列柴油机在铁路上的应用

德国ＭＴＵ公司生产的３９６系列柴油机广泛应用于铁路电传动和液力传动内燃机车，内燃动车以及用于列车供电的发电车，至今已售出１６００多台，其中累计工作时间最长的已超过９００００ｈ。文中介绍了该系列柴油机的主要设计特点以及最近所作的技术改进，列举了若干该系列发动机的典型应用实例。     

Influence of Liquid Load Shift on the Dynamic Response of Articulated Tank Vehicles

The influence of the lateral load shift on the dynamic response characteristics of an articulated tank vehicle is investigated assuming inviscid fluid flow conditions. A quasi-dynamic roll plane model of a partially filled cleanbore tank of circular cross-section is developed and integrated to a three-dimensional model of the articulated vehicle, assuming constant forward speed. The destabilizing effects of liquid load shift are studied by comparing the directional dynamics of the partially filled tank vehicle to that of an equivalent rigid cargo vehicle subject to steady steer input. Dynamic response characteristics demonstrate that the stability of a partially filled tank vehicle is adversely affected by the Liquid load shift The distribution of cornering forces caused by the liquid load shift yield considerable deviation of the path followed by the liquid tank vehicle. The influence of the vehicle speed on the dynamics of the liquid tank vehicle is also investigated for variations in the fill levels and fluid density.     

Liner costs and pricing polices: a reconsideration of regulatory issues

A number of shipping analysts have adopted as a convenient approximations, the assumption that linear costa are homogeneous per unit of cargo. The paper points to recent evidence suggesting that considerable differences exist in the estimates of implicit marginal cost for various types of cargo, and re-evaluates the regulatory arguments which are based on the assumption of homogeneity of costs.     

Interval constraints for the treatment of the partial data problem in gravity model calibration

The problem of indeterminacy, in the solution parameters of the Evans-Kirby calibration model, is discussed. A proposal is made to alleviate this problem, in the case of missing data, by introducing interval constraints.