Optimizing shipping company operations using business process modelling

In order to identify the elements constituting quality in services, a business process modelling methodology has been applied in the case of a Greek liner shipping company. The company operations have been identified and analysed in order to assess the complete performance of service elements and thereafter identify how to match the service performance against the user requirements. A liner container service within Europe has to compete with the road transport which, in many cases, is an alternative to the sea transportation and not complementary to it. Thus, not only the ship has to be envisaged when aiming to improve quality in services but also the whole chain, namely port authorities, land transportation enterprises, subcontractors, agents, charterers and others. A set of potential improvements within this framework are thus suggested and time and cost (examined in a specific voyage scenario) are measured before and after the implementation of these measures. Very large time and cost savings are observed after the application of the technology improvements, allowing, in fact, the shipping company to even increase the number of round trips per year in the examined route. This indicates that very large benefits can be drawn by analysing and critically adjusting business processes in modern shipping companies.     

Importance of ocean circulation in ecological modeling: An example from the North Sea

There is an increasing number of ecological models for the North Sea around. Skogen and Moll (2000) [Skogen, M.D., Moll, A. 2000. Interannual variability of the North Sea primary production: comparison from two model studies. Continental Shelf Research 20 (2), 129–151] compared the interannual variability of the North Sea primary production using two state-of-the-art ecological models, NORWECOM and ECOHAM1. Their conclusion was that the two models agreed on an annual mean primary production, its variability and the timing and size of the peak production. On the other hand, there was a low (even negative dependent of area) correlation in the production in different years between the two models.In the present work, these conclusions are brought further. To try to better understand the observed differences between the two models, the two ecological models are run in an identical physical setting. With such a set-up also the interannual variability between the two models is in agreement, and it is concluded that the single most important factor for a reliable modeling of phytoplankton and nutrient distributions and transports within the North Sea is a proper physical model.     

Dense network traffic models,travel time reliability and traffic management. Ii: Application to network reliability

This paper is the second of a pair of papers discussing two main themes concerning dense network modelling. These themes are: (1) the changing nature of traffic management technology and the underlying objectives behind traffic management practice, and (2) the use of measures of network reliability in models, especially as an element of the evaluation of alternative network configurations. This paper develops and applies the second theme, the use of network reliability concepts in the evaluation of traffic networks, through consideration of variations in travel times, distinction between local street and arterial road networks, and the definition and application of a set of reliability indices that may be used to study different trip movements in a network. It indicates how these indices may be used in appraising different traffic management plans for a dense network of local streets and arterial roads, using a case study application.     

On the feasibility of the optical steering wheel sensor: Modeling and control

This paper discusses the development of a system model for the wireless steering wheel angle sensor and steering wheel system for the evaluation of the steer by wire system in a vehicle dynamic system. The steering wheel sensor is a wireless, contact-less sensor utilizing an optical medium for angle detection. The optical medium is operated based on a photodiode and photo-detector head. A reflecting disc or code-wheel, working similar to a compact disc, is used to reflect the light from the photodiode back to the photo-detector. The beam is reflected based on the content in the reflective disc to measure the relative angle through a micro-controller. The proposed wireless steering sensor and steer by wire system is modeled using the Matlab/Simulink and their performance is investigated to evaluate the steering response, vehicle dynamics, and steering feel of the system. Finally, the feasibility of the proposed system is discussed based on the developed model and simulation results.     

Temps de transport au regard des changements démographiques en Île-de-France. Tendances passées et projections à l’horizon 2030

This paper investigates the evolution of travel time through travel time budget in the most densely populated region of Paris and its neighbouring regions, where the GDP per capita is the highest in France. Four consecutive household travel surveys available from 1976 up to 2001 allow us to compare travel time and travel time budget over the years and also to forecast Parisian mobility up to 2030. We have chosen to focus on the distinction between mandatory and non-mandatory trips, mandatory trips being defined as trips whose destinations are related to work, university or school. We have studied travel time related to demographic, socio-economic and geographical patterns in order to identify some key elements determining travel time and urban mobility.     

Heat exchanger/catalytic system for reducing the exhaust emissions from diesel engines

A system has been researched over the past 3 years for reducing the exhaust pollutants from diesel engines for light commercial vehicles. The system researched achieves Euro 6 standards for reduction of polluting gases (CO, HC, PM, NO). It consists of 4 main sections: 1. A heater and heat exchanger (HE); 2. A CO/HC oxidising catalyst (D°C); 3. Pt catalyst on a diesel particulate filter (DPF); 4. A NO reducing reaction (SCR) within the DPF. The system operates as follows. The exhaust gas contains oxidising gases, namely both O₂ and NO₂. The levels of CO and HC are oxidised by O₂ to CO₂ for temperatures above 200°C. Carbon (PM) is oxidised to CO₂ by NO₂ but requires a temperature above 250°C. The operating exhaust temperature of 300°C is ideal for the removal of NO by using the Pt catalyst and the CO generated within the DPF. The heater is required to be able to raise the exhaust temperature at any time to 300°C in order to optimise the performance of the system, since diesel engine exhaust temperatures vary between 160°C (slow speeds) to 350°C (high speeds). Considerable heat is required (??3 kW) to maintain the exhaust gas for a 2l engine at 300°C for engine idle conditions. Therefore a heat exchanger is required to re-circulate the input heat and thereby reduce the maximum power consumption to a maximum of 500W over the engine full operating test cycle. This energy is supplied by the engine battery and alternator. Experimental results have been obtained for the exhaust from a Kubota diesel engine and the reductions in exhaust emissions of 83% (CO/ HC), 58% (NOx) and 99% (PM) were obtained. The PM was continuously cleaned so that there was no build up of back pressure.     

Introduction

The papers in this special issue on transportation network design were first presented at a workshop held at the University of Illinois in September 1977 under the auspices of the Mathematical Social Science Board with the support of the National Science Foundation. The participants in the workshop included most of the leading research workers on formal models of transportation network design. The extensive discussions of the papers that ensued during the two-day workshop led to several suggestions that may be useful in stimulating new research directions and increased research activity on design models.     

Traffic assignment in a two-dimensional continuous representation of a traffic network with flow-dependent speeds

The work deals with the assignment of traffic to a two-dimensional continuous representation of a traffic network. An important aspect of the treatment is that the reciprocal of the speed on each road in the network is at all times a linear function of the flow on that road. This speed-flow relationship is generalized to two-dimensional space using travel intensities and taking account of road densities, so that there is direct dependence of speeds upon flows at all points regardless of their location. There is also dependence of flows upon speeds at all points because Wardrop's first assignment principle is adopted. That is, for a given O-D pair, journey times on all routes actually used are identical, and less than journey times on all other possible routes. This results in the identification for each O-D pair of an “assignment zone”, an area within which all trips between that O-D pair are made, and beyond which no such trips are made. For a single O-D pair the assignment zone is identified by ?_m, the maximum angular divergence of a path from the straight line between O and D. Paths are then assumed to be bilinear so that for a single O-D pair the assignment zone is a parallelogram. Journey times, speeds, lateral displacement and other related quantities are obtained as functions of the flow Q between O and D. The work is extended to three O-D pairs located at the extremities of an equilateral triangle and four O-D pairs located at the corners of a square. At low flows these two configurations are trivial extensions of the single O-D pair problem because assignment zones do not overlap. At higher flows account is taken of this tendency to overlapping, so that although they do not overlap they do touch, becoming kite-shaped. Origins and destinations are assumed to be at the periphery of small circles of arbitrary radius. The work is inelegant to the extent that it involves a numerical integration but it is possible that this might eventually be circumvented.     

锰粉加工工人心血管功能的调查研究

对 ５５ 名锰粉加工工人和 ５６ 名对照工人的调查结果显示，工人工作地点 Ｍｎ Ｏ２ 浓度几何均值为 １９６ ｍ ｇ／ｍ ３ （锰尘 ０１７～２２．２４ ｍ ｇ／ｍ ３ ），样品超标率 ８８７％ 。接触组头晕头痛、睡眠障碍、容易疲劳和记忆不良的主诉率明显高于对照组（ Ｐ＜００５～００１）。接触组和对照组的心电图异常、高血压和低舒张压检出率未见显著性差异，其心率、 Ｐ Ｒ间期、 Ｑ Ｒ Ｓ波、收缩压和舒张压的均值比较也没有显著性差异。接触组心电图异常和低舒张压的 Ｏ Ｒ分别是 １．５６（９５％ 可信区间为 ０７０～３．５０）和 ２．０８（９５％ 可信区间为 ０１８～２３．５７）。     

High Performance ACC System Based on Sensor Fusion with Distance Sensor, Image Processing Unit, and Navigation System

Curve sensors used in first generation “Adaptive Cruise Control” systems (ACC) are based on steering angle sensors, lateral accelerometers or yaw rate sensors. The disadvantage of these curve sensors is that they do not have any preview characteristics. This leads in many driving situations to misinterpretations by the ACC system, e.g. wrong path assignments of vehicles ahead because of non-constant curve radii particularly in the beginning and ending of curves. The consequence is that the ACC car brakes due to vehicles in adjacent lanes or it ignores relevant obstacles. In the following a second generation ACC system will be presented whose curve sensor is realized by a real time image processing system with the support of a GPS-based navigation system. This multi-sensor fusion system is now suitable for collision avoidance and stop and go applications.