Showing papers on "Fleet management published in 1979"

Air Fleet and Facility Planning via Optimal Control Models

Abstract: A study is presented which is aimed at developing techniques suitable for effective planning and efficient operation of fleets of aircraft typical of the air force of a developing country. An important aspect of fleet management, the problem of resource allocation for achieving prescribed operational effectiveness of the fleet, is considered. For analysis purposes, it is assumed that the planes operate in a single flying-base repair-depot environment. The perennial problem of resource allocation for fleet and facility buildup that faces planners is modeled and solved as an optimal control problem. These models contain two "policy" variables representing investments in aircraft and repair facilities. The feasibility of decentralized control is explored by assuming the two policy variables are under the control of two independent decisionmakers guided by different and not often well coordinated objectives.

Vehicle attributes constraining present electric car applicability in the fleet market

Abstract: One strategy for reducing petroleum imports is to use electric cars in place of conventional vehicles. This paper examines obstacles which electric cars are likely to encounter in attempting to penetrate a key segment of the passenger car market, namely, the fleet market. A fleet is here defined as a group of cars operated by a corporation or a government agency. The primary data source is a questionnaire that was distributed to fleet operators by the Bobit Publishing Company in the summer of 1977. Six sectors of the fleet market were sampled: police, state and local government, utilities, taxi, rental, and business. The questionnaire was specifically designed to uncover factors limiting market penetration of unconventional vehicles, although no attempt was made to determine price elasticities. Emphasis is on vehicle attributes that are readily quantifiable and relatively projectable, including seating capacity, range, battery recharging characteristics, availability of power options, and ability to use interstate highways.

Commercial vehicle surveys

Abstract: This paper was presented at Session 37 - Freight. Most of the mass and dimension limits for commercial vehicles recommended by the NAASRA Economics of Road Vehicle Limits (ERVL) study were put into operation in Victoria in November 1976 under an extension of the permit system. The Country Roads Board conducted a limited survey on the Hume and Western highways in 1977-78 to monitor the effects of the new limits. This paper describes the organisation of the 1977-78 survey and compares the data obtained with those from earlier surveys, particularly those carried out in 1974-75 as part of the ERVL study. The latest survey indicates that there have been significant changes in the makeup of the commercial vehicle fleet over the past three years, with the proportion of large vehicles increasing dramatically. There has been a strong trend for triaxles to replace widespread tandems on the heavier articulated vehicles. Even though operators have taken advantage of the increased limits allowed by the permit system, axle loadings have not increased to the extent that significant increases in pavement damage can be attributed to the introduction of the permit loadings (a). (TRRL)

Development of efficient central management strategies for advanced group rapid transit systems

Abstract: This paper presents a summary of a computer-aided method for developing efficient central management system strategies for advanced group rapid transit systems by use of medium-sized, automatically controlled vehicles that travel on dedicated guideways. Some efficient central management system strategies developed for a test network that uses the method are presented and discussed in detail. The method consists of an iterative process in which experienced transit system operators make complex, judgmental decisions and a computer performs extensive and repetitive computations. This computer-aided method allows transit system operators to compare the consequences of various central management system strategies in terms of such measures as passenger wait times, number of passenger intermediate stops, vehicle fleet size, vehicle load factor, and vehicle flows in various guideway sections and at various passenger stations. After studying such measures, operators can develop a set of efficient and realistic central management system strategies. The computer-aided method and the associated computer simulation program are general in nature and can be used to develop central management system strategies for a variety of network configurations and trip demand data. /Author/

The role of the federal government in u.s. marine transportation

Abstract: The United States meets the world shipping crisis of the 1970s with a high-cost merchant fleet and a national maritime policy which needs clearer articulation. This paper examines the objectives, rationale and methods of implementation of the US maritime programme with attention, finally, to the question of governmental reorganization.

Airline fleet planning and airport construction

Abstract: The relationship between airline fleet planning and the construction of airports is studied to determine the use of optimization procedures in the decision process, JASPER (Joint Air Services Planning and Evaluation Review) is set out as a framework to handle the information requirements of government, airlines, and the general public. Analysis of aircraft/airport costs over time, making use of computer simulation produces an important means of determining the timing for public and private investment decisions.

Cost forecasting for international airline operations

Abstract: Cost models are constructed and calibrated to describe airline operating costs in selected international markets. These models are then used to demonstrate how operating costs can be forecast for relatively short time horizons, such as three years. The models confirm the concept that operating costs in different markets of the world air transportation system are significantly different. The reasons for this include the geographic characteristics of the different markets in terms of stage lengths and network structure and the differences in input prices for items such as fuel and labor. Fleet mix is also an important determinant of operating costs. The use of wide-body aircraft is seen to have a significant impact on reducing airline operating costs. Recently, operating costs have tended to decline in real terms but to increase in current terms. The forecasts made for a three-year period indicate that these trends might continue. These forecasts, however, are strongly dependent on assumptions regarding fuel prices. (Author)

Systems analysis for planning of air fleets and maintenance facilities

Abstract: The high cost and extraordinary demands made on sophisticated air defence systems, pose hard challenges to the managers and engineers who plan the operation and maintenance of such systems. This paper presents a study aimed at developing simulation and systems analysis techniques for the effective planning and efficient operation of small fleets of aircraft, typical of the air force of a developing country. We consider an important aspect of fleet management: the problem of resource allocation for achieving prescribed operational effectiveness of the fleet. At this stage, we consider a single flying-base, where the operationally ready aircraft are stationed, and a repair-depot, where the planes are overhauled. An important measure of operational effectiveness is ‘ availability ’, which may be defined as the expected fraction of the fleet fit for use at a given instant. The tour of aircraft in a flying-base, repair-depot system through a cycle of ‘ operationally ready ’ and ‘ scheduled overhaul ’ phases is represented first by a deterministic flow process and then by a cyclic queuing process. Initially the steady-state availability at the flying-base is computed under the assumptions of Poisson arrivals, exponential service times and an equivalent singleserver repair-depot. This analysis also brings out the effect of fleet size on availability. It defines a ‘ small ’ fleet essentially in terms of the important ‘ traffic ’ parameter of service rate/maximum arrival rate.A simulation model of the system has been developed using GPSS to study sensitivity to distributional assumptions, to validate the principal assumptions of the analytical model such as the single-server assumption and to obtain confidence intervals for the statistical parameters of interest.