This paper makes an analytical and empirical study of distributing items by trucks from a supplier to many customers located in a surrounding region. The total logistic cost of a supplier and customers is formulated and minimized to determine the optimal time between dispatches. Customer service must be simultaneously considered for logistics management and its factors are represented by both average lead-time and the time between deliveries to each customer. The empirical analysis of trade-off between logistic cost and customer service implies that a supplier tries to gurantee higher level of customer service than that achieved by total cost minimization. This is a feature of Just-in-Time distribution strategies.
For the purpose of increasing visibility of road markings at night, glass beads are mixed in and sprayed on the road markings. Almost all past studies on the retro-reflective characteristics of the glass beads are executed by means of experimental approaches. Here, a technique of three-dimensional numerical analysis is proposed, and the proposed method is developed to be applicable to various condition of road markings, such as: material of road markings, quality and quantity of glass beads, and geometric and traffic features of road. It is ascertained that the numerical results are fairly well agree with the observed ones. And we make clear how to fix glass beads in road markings for the purpose of getting efficient visibility.
It is said that some evacuation places in urban areas are threatened by fire spreading. In this paper, first four systems (1, 2, 3, and 4) are drawn up as alternatives of the risk assessment system based on several fundamental models. Then, a verification test of them is done using two experimental criteria, and System 2 and 4 are selected as promising ones. Next, comparative simulation analyses are done and the following is shown: i) System 2 places a greater estimate on risk than does System 4. ii) System 2 is sensitive to “velocity of wind”, while System 4 is sensitive to “size of fire”. Finally, application studies are carried out and the zone of about 50 or 70m from flare is assessed to be at danger in the case by either system.
Large cities face the serious congestion problem of urban mass transportation, e. g. over 250% in the rush hour. An offer of good service such as the introduction of the train of the good quality is considered as an urgent necessity. Thus the purpose of this paper is threefold; 1) to estimate the users willingness to pay for high quality services, 2) to find the choice behavior of high-graded train and ordinal train by constructing the discrete choice model based upon the stated preference data and 3) to estimate the social surplus taking account of the cost for the introduction of this new service. The study finds that the introduction of the service with the price of 600yen per trip generates considerable social benefit.
This paper discusses evaluation measures for flexibility of “opportunity sets”, from which a consumer chooses objects over time. In particular, it concerns binary relations on the opportunity sets which satisfy an axiom for “preference for flexibility”; a consumer is assumed to possess state dependent preferences for objects; a set x is supposed to be preferred to x'; in terms of flexibility in choice, if and only if, no matter what state ensues, there is something in x as good as everything in x'. We present a general form of evaluation indices for flexibility in choice, which are relevant numerical representations of an underlying preference on sets. Log-sum utility measures derived from random utility theory may belong to the general class of indices for the evaluation of flexibility in choice.
Fuzzy inflow control model was introduced as an advanced control method on urban expressway. Though reality of the model was confirmed in some previous studies, variation of control method should be discussed to use the model in general aspects. First, fuzzy inflow control model was rebuilt considering practical application in the study. Database, explanatory variables, rule-base, and membership functions were investigated. Second, the control model combined with traffic simulation was proposed to show effects of rules defined for control action. Three case studies were displayed to use the model practically.
The merging probability is often calculated to evaluate the capacity or the level of service of on-ramp terminals of expressway systems. The probability is, however, mostly the probability of single merges. On the merging area of heavily loaded urban expressways such as the Hanshin Expressway, however, two or three vehicles often merge into a through traffic gap all at once. In this study, attention was given to the multiple merging phenomena and the computation process of the multiple merging probability. Traffic survey was conducted at merging terminal of the Hanshin Expressway using a television camera. The multiple merging probability can be computed by evaluate the difference of the shoulder lane gap and the sum of the gaps between vehicles that make multiple merging from the ramp. The multiple merging probability was compared with actual data.
In this paper the causes of decrease in the number of bus passengers are analyzed using the data of public bus enterprises in Japan. Although the spread of private-car owners looks like one of the most important factors, it is nothing but a primary one. The passengers' behavior has been influenced more directly by the fare rises. The passengers decrease consists of the short-term one and the long-term one which have their own mechanism. The latter has begun at a “turning point” when the fare level overtook the consumer's price level. After that point there is a correlation between the rate of fare rise (X) and the rate of decrease (Y) as shown by Y=1-exp[-0.47X].
Trip generation model have generally received less attention than other aspects of travel decision making. This paper presents some explorations into structure of trip decisions for non-grocery shopping and a possibility of applying choice model for trip decisions. Firstly, we assume the nested-choice-structure of shopping behavior, which consists of three dimensional decisions with frequency choice at top level. Secondly, we examine two choice models to describe frequency choice; one is “Ordered Logit Model” by Sheffi (1979), another is “Repeated Logit Model” based upon binomial distribution. Using data of monthly shopping trips on holiday, we present the validity of this nested structure, and the effectiveness of two choice models in this structure, comparing with general linear model. And we propose “Partially Constrained O. L. Model” that is a more effective version of “O. L. Model”.
Precedence Network model originally developed by Crandall, K. C. has been revised as to permit two types of time lag values for each FS, FF, SS, SF relation. Though the revised Precedence Network model can be, of course, solved by introducing forward pass and backward pass calculation algorithm of PERT, formulating as Linear Programming problem is proposed to both cases that job-interruption is not permitted and freely permitted. First of all, the revised PN model is compared with PERT model from some points of view and then theoretical inquiry is observed for the solution of PERT model as LP problem. The revised PN model is also formulated as LP problem and applied to a small project network.
This paper provides an analytical framework to investigate the structure of local service markets with entry barriers, and to assess the viability of the local markets. Except in the short run, both market structure and service quality are endogenous; both depend on basic ingredients, such as technology of R & D, demand conditions, natures of factor markets, knowledge accessibility and basic functions of local human networks. In our markets of non-daily consumed services, services are supposed to be horizontally differentiated per se; firms are assumed to maximize their collusive profits. A theoretical model is presented to explain the relationships between market structure and market environment. Two measures, IUs (Indirect Utility Indices) and NNEs (Normalized numbers of entrants), are proposed to investigate the market viability. An empirical research is also carried out to illustrate the applicability of our indices.
Urban Economics has a long history of dealing with spatially differentiated markets, where consumers face their choice of both quality and quantity. Although there have been both theoretical and empirical researches, the general aspects of the problem have not been investigated. The aim of this note is to propose a general framework of dealing with the consumer's choice of quality and quantity. We apply our approach to housing markets to propose a residential equilibrium model, in which the equilibrium rent function emerges from the interaction between the supplier and demander of the housing lots. A simple comparative analysis is carried to investigate the impacts of increases in population on the gradient of the housing rent and land price.
A technique for estimating the number of intra-zonal work trips for each zone around the downtown areas has been dealt with in the authors' last paper. But there has been left a question to be studied in detail: How would the number of railway lines run radiately from each zone affect the number of intra-zonal work trips? In this study, the above question is mainly examined. A finding in this study is that the number of railway lines is not a basic factor which determines the number of intra-zonal work trips for each zone around the downtown areas. Therefore, the basic factors are the employment density and the zone area. The estimated numbers of intra-zonal work trips for 1980 from the model calibrated for the base year (1970) are compared to the actual figures in 1980. This comparison gives us a high degree of correlation.