Capacity estimation of torque converters with piston holes using the response surface method and an artificial neural network

In new slim torque converters, lock-up clutches are used to provide high fuel efficiency at low speed. However, the slimness of the converters causes difficulty in heat dissipation, which may damage the friction material and shorten its life span. A cooling hole in the lock-up piston reduces the heat but also reduces the torque because oil flows through the hole due to the pressure difference between the two faces of the piston. In the early stages of the development of this type of torque converter, designers must consider the minimum flow rate required to cool the friction material and the minimum torque capacity required to transmit the engine torque. This research explored two methods of estimating these parameters. In the first method, an estimation equation was derived by combining the response surface method with physical properties such as the centrifugal force, a sudden expansion, a sudden contraction, and the steady flow energy equation. The second method involved the use of an artificial neural network. The feasibility of the estimates based on statistics and on the artificial neural network were confirmed in the design stage by comparing experimental and estimated data. An estimation program was created using the C#.Net language and has been used for actual torque converter designs by the Korea Powertrain Company.     

Development of a telematics evaluation environment based on a driving simulator and its application

For developing telematics devices, traditional development methods include the unit function test, compatibility test and T-Car, which have some limitations. Telematics devices have various functions that require accounting for the interactions among three major elements of automotive electronics: the vehicle, the device unit and driver. The KAAS (KATECH Advanced Automotive Simulator) system is a virtual-reality-based test environment designed to test and analyze the three elements in one place. One of the difficult functions when constructing such VR (Virtual Reality)-based telematics test environment is to develop a test method for the LBS (Location-Based Service) function such as a car navigation demanding the GPS (Global Positioning System) satellite signals because KAAS is in a fixed laboratory. To overcome these problems, a real-time GPS simulation system, which can be integrated with KAAS, is needed because the location of the vehicle in virtual space is determined purely by the driver’s personal intention while driving virtually. This paper presents new concepts needed to construct a VR-based telematics test environment to generate a GPS RF signal, which reflects the continuously changing vehicle location during virtual driving in real-time. To construct this system, the coordinate transform must be conducted from a rectangular coordinate system that is compatible with a virtual 3D DB that is used to construct a 3D image for KAAS using a WGS84 and a longitude-latitude coordinate system compatible with a GPS simulator. Moreover, the real-time HILS (Hardware In Loop Simulation) systems and the CDMA (Code Division Multiple Access) simulation system are developed to evaluate telematics devices. Finally, we show its applications and results.     

Forecasting fishing vessel responses in coastal areas

A system for forecasting the operability of ships was developed by extending a wave forecasting system with the ship responses to the forecast sea states. The system produces 4-day wave forecasts in an implementation for the Portuguese Exclusive Economic Zone, where the vessels’ seakeeping performance is forecast, although the method presented could well be applied to any other coastal region. The proposed procedure requires the knowledge of the transfer functions for different ship speeds and headings. The computations are made for two different types of fishing vessels that currently operate in the Portuguese coast. Ship motions and derived responses are evaluated with a strip theory code and compared with the prescribed values of relevant seakeeping criteria that represent the limit conditions that still allow standard operational conditions for those vessels. For each forecast sea state at each grid point at a given time, the response spectrum is calculated and operability indexes are computed and compared with the maximum allowed values for a specific operation criterion. The results are presented as operational index maps for various areas of the Portuguese coast, and the information provided by system will help ship masters to plan the operation of their ships, namely to decide the areas to operate in anticipation. In this way, they can identify areas in which the level of operationally of their ships will be degraded due to weather conditions and avoid them.     

Establishing performance targets for shipbuilding policies

Shipbuilding is the subject of public policies in a number of countries, as it is considered a strategic industry and has an impact on employment levels in many regions. Establishing performance targets can be a challenge to shipbuilding policy makers. This paper suggests an approach to this problem, based on the Data Envelopment Analysis (DEA) technique. This approach makes it feasible to estimate productivity and building time potential, taking into account the output pattern, technological level and quality of the industrial environment of the country or region. The methodology is applied to the analysis of the competitive potential of some Brazilian shipyard models. The benchmarking analysis was carried out for a sample of shipyards from the world's principal shipbuilding blocks.     

Emergence of ‘new professionalism’ among Chinese seafarers: empirical evidence and policy implications

In this paper some of the factors that were influential in establishing a Canadian shipping policy position à proposissues raised by the UNCTAD V meeting are examined. The first of these issues was the question of early ratification and entry in force of the Conventin on a Code of Conduct for Liner Conferences. The second involved the relationship between flages of convenience and fleet expansion in the developing countries (LDCs). The third concerned LDC participation in the carriage of bulk cargoes. The author concludes that Canada's stance was determined by the fact that she was a major user of shipping withouta significant fleet of her own, and shows how she attempted to balance her sympathy with Third World aspirations with the demands of her own national interests.     

Analyzing aviation safety: Problems,challenges, opportunities

This paper reviews the economic literature relating to aviation safety; analyzes the safety record of commercial passenger aviation in the United States and abroad; examines aviation security as a growing dimension of aviation safety; and identifies emerging issues in airline safety and challenges for aviation safety research. Commercial airline safety has improved dramatically since the industry's birth over a century ago. Fatal accident rates for large scheduled jet airlines have fallen to the level where (along many dimensions) aviation is now the safest mode of commercial transportation. However, safety performance has not been evenly distributed across all segments of commercial aviation, nor among all countries and regions of the world. The finding that developing countries have much poorer safety records has been a persistent conclusion in aviation safety research and continues to be the case. Unfortunately, operations data are not available for many of the airlines that experience fatal accidents, so it is not possible to calculate reliable fatality rates for many segments of the worldwide aviation industry. Without more complete information, it will likely be difficult to make substantial improvements in the safety of these operations. Challenges to improving aviation security include: how much to focus on identifying the terrorists as opposed to identifying the tools they might use; determining how to respond to terrorist threats; and determining the public versus private roles in providing aviation security. The next generation of safety challenges now require development and understanding of new forms of data to improve safety in other segments of commercial aviation, and moving from a reactive, incident-based approach toward a more proactive, predictive and systems-based approach.     

Book reviews

Practice, Politics and Policies—"The Politics of Transport”. By Enid Wistrich. (Harlow, Essex: Longman Group Limited, 1983.) [Pp. 185, with index.] £4·25.

Econometric Analysis and Railway Costing. By W. G. Waters, II and A. D. Woodland. (North Oxford Academic, 1984.) [Pp.132.] £12·95.     

A multi-criteria decision support methodology for implementing truck operation strategies

This study proposes a multi-criteria decision support methodology to enable the prioritization of potential alternative transportation system operations strategies and then demonstrates the effectiveness of the methodology using a case study involving truck operations. The primary feature of this methodology is its ability to help policymakers consider economic, public, and private sector standpoints simultaneously. The economic criterion is cost to the public sector where four criteria related to truck impacts on the transportation system are incorporated. These are traffic congestion, safety hazards, air pollution, and pavement damage. In addition, reliability and productivity are regarded as metrics representing the private sector viewpoint since they can significantly affect profitability. The methodology combines qualitative and quantitative aspects of these standpoints. In order to demonstrate the applicability of this methodology, a corridor with some of the highest truck traffic in the US is selected as a case study and three forms of left lane restrictions for trucks are considered. For qualitative analysis, survey data were collected from two groups classified as public agency and transportation industry professionals who are experts in trucking. In addition, a micro traffic simulation model was used to produce various performance measurements that can describe quantitative impacts. As a result, the methodology provides a rational argument for prioritizing potential alternative truck strategies.     

Airline Jet Fuel Hedging: Theory and Practice

Abstract

Most international airlines hedge fuel costs, but the theoretical justification behind this action is weak. The paper explores the nature and extent of airline fuel hedging and asks why airlines hedge. The availability of hedging instruments is first discussed, with the most liquid markets in crude and exchange traded contracts. Aviation fuel contracts are possible, but with counter‐party risk. Most major passenger airlines with sufficient cash and credit now hedge at least part of their future needs. Hedging does protect profits against a sudden upturn in crude prices caused by political and consumer uncertainty leading to slower economic growth. However, if higher oil prices are induced by strong economic growth and oil supply constraints, hedging increases volatility with hedging gains reinforcing improved profits from higher traffic and improved yields. If hedging does not reduce volatility, it may still have an accounting role in moving profits from one time period to another, insure against bankruptcy, and signal the competence of management to investors and other stakeholders.