Search

Copyright of International Journal of Production Research is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper reviews the goal approach and the system resource approach to the study of organizational effectiveness. First, the goal approach is defended with respect to criticisms made by the users of the system resource approach. Next it is criticized for its failure to develop general measures of effectiveness. The system resource approach is then criticized because optimization is not measured, few general measures are used, and the basic rule of mutual exclusiveness is seriously violated. Finally, a general measure of effectiveness is suggested, based on Georgopoulos and Mann's (1902) study of community general hospitals. [ABSTRACT FROM AUTHOR]

This paper looks at the inventory-related models published during the last ten years from the systems point of view. A chart is given to show the broad categories of inventory models. The paper first lists eleven quantifiable and four nonquantifiable variables (and their types) that go into inventory formulas, affect inventory decisions, and have already been identified by the researchers. Next, various research papers are grouped in six categories based on similarities of approaches used by these papers. These categories are : (1) models for determining optimum inventory policies, (2) lot size optimization, (3) optimization of various specific management objectives, (4) models for optimizing highly specialized inventory situations, (5) application of advanced mathematical theories to inventory problems, and (6) models bridging the gap between theory and practice. Next a synthesized review of recently published models belonging to each individual category is presented, and salient features of individual studies are highlighted. Further, this paper discusses the difficulties that most commonly arise in applying these models to routine practical inventory situations ; and it also lists the weaknesses (or limitations) of certain assumptions commonly made by the researchers for developing inventory models. In the end, the paper makes several suggestions about how the available results of inventory models can beat be used in practice. [ABSTRACT FROM AUTHOR]

Optimization is rightly claimed to be the most significant factor distinguishing the modern approach to machining processes from the orthodox one. Practical results can be obtained from the application of mathematical modelling and optimization techniques.
The paper presents a procedure for solution of machining process optimization problems, with the use of theory of graphs and Bellman's optimum principle.
The finite graph G=(N, A) (where N denoted a set of nodes and A the set of arcs) here presents the set of feasible solutions. Each arc represents a corresponding machining operation and each path the feasible machining process.
A number can be associated with each are the increment of criterion for optimality. Using the optimum principle we can find the shortest possible path in the graph, thus solving given problems of choice for the optimal machining process.
There is a variety of ways in which the performance criterion can be formulated. In this paper only those performance measures having sufficient economical justification are considered. We may minimize the costs of machining processes, or optimize economical effectiveness of capital engaged.
The method presented can be applied with every additive criterion, as well as with some non-additive ones. A practical example illustrates the field of possible application of this method. [ABSTRACT FROM AUTHOR]

The paper discusses planning problems which arise when different products are manufactured on several assembly lines and production has to be co-ordinated with other manufacturing centres. In a limited labour market flexible production capacity requires the transfer and retraining of existing workers.
The first section of the paper explores the simplest possible planning element which still contains enough of the essence of the problems to shed some light on the nature of a solution. This model consists of the planning of production of a single product in one location, under the supposition that teams of girls may be relinquished to (or obtained from) a labour reservoir at a penalty which corresponds to retraining costs. A production planning game based on this model is constructed, and played with teams of human planners. The game is also played by means of two types of systematic decision rules:(1) a linear production smoothing rule; (2) the optimum rule for the game, developed by dynamic programming. This permits a comparison of the efficacy of human planners in comparison to automatic decision rules.
The dynamic programming model is extended in the next part of the paper to cover a more realistic model of the situation. The results of the dynamic programming analysis are shown to be a very valuable tool for the production planning of several product types in one plant, as well as for the co-ordination of different plants. [ABSTRACT FROM AUTHOR]

Copyright of INFOR is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of INFOR is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper deals with a theoretical programming method for determining conditions of unit cost reductions of dynamic technological processes. The mathematical model has been adopted for use as a dynamic programming procedure. The necessary assumptions needed to use the procedure have been formulated.
The more important part of the work is the optimum principle, enabling the solution of a wider class of problems than is possible with the commonly applied R. Bellman's Principle. In place of the assumptions on critical functional additivity (i.e. the additive nature of costs) due to several trajectory elements (e.g. technological operations), more general moments were introduced. These can be stated as 'the costs of the functional value of the first part of the trajectory causes an increase of the functional value for the entire trajectory, regardless of its second part' and 'each intermediate state required in reaching the optimum of the whole process, is to be reached in an optimal manner'. [ABSTRACT FROM AUTHOR]

Optimization techniques are widely used in many areas and frequently developments of a technique in one area open up opportunity for its use in other areas. This paper presents examples of how the newer techniques have contributed to the improvement in technological processes.
After a brief discussion of optimization, available optimization techniques are classified and the principles of constraint and uncertainty programming outlined.
The application of current techniques to design problems in various production disciplines are then discussed and the Appendix presents some problem solutions. [ABSTRACT FROM AUTHOR]

This paper discusses the use of the geometric programming technique to determine the cutting speed and feed which yield minimum production cost. The method provides for simultaneous determination of the cost optimum values of speed and feed and allows for the incorporation of restrictions on the allowable levels of the machining variables. [ABSTRACT FROM AUTHOR]

This paper gives the results of computations, for a chosen production control model, yielding the extra costs incurred when information about a change in mean demand level becomes available at some rime relative to the time of the change. These extra costs are zero if the information is available from prehistoric times and increase monotonically as the detection moment shifts to later points of time. Only "jumplike" changes of mean demand level are considered. It is found that the extra costs as a function of the detection moment N approach a linear asymptote for high N. The points of contact of these results with control chart theory, especially the optimization of control charts as a link between predictors and production control, are mentioned. [ABSTRACT FROM AUTHOR]

Copyright of INFOR is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Experimental design considerations have been virtually ignored by economists who have conducted computer simulation experiments with models of economic systems. The objective of this paper is to spell out in detail the relationship between existing experimental design techniques and techniques of data analysis and the design of simulation experiments with economic systems. We begin by defining the problem of experimental design as applied to computer simulation experiments. With the aid of an example model, we explore several techniques of data analysis and a number of specific experimental design problems. Although this paper is oriented towards the design of computer simulation experiments in economics, the techniques which are discussed are of a general nature and should be applicable to the design of simulation experiments in other disciplines. [ABSTRACT FROM AUTHOR]

This paper discusses a type of multimode monopulse feed using corrugated circular waveguide. The 'difference' or error-signals are derived from the TE and/or TM modes, whereas the 'sum' or reference-signal is provided by the so-called hybrid modes. The optimization of the overall tracking performance is carried out in two steps. The horn dimensions are first chosen to give the optimum 'difference' mode illumination, then the 'sum' mode efficiency is optimized by shaping the ' sum ' pattern with the aid of higher-order hybrid modes. It is shown that the performance of a corrugated waveguide monopulse feed is, in many respects, superior to that of its conventional counterpart. [ABSTRACT FROM AUTHOR]

The performance of corrugated waveguide borns for paraboloidal reflector antennas is optimized by shaping the radiation pattern with the aid of a high speed digital computer. The same basic program can be used for either the efficiency or signal-to-noise ratio of the system. It is shown that the effect of spill-over loss is to increase the contribution of ambient or ground temperature to the overall system noise. In addition, for the same reflector the optimum waveguide size required to give the maximum signal-to-noise ratio will increase as the ambient temperature increases. Results related to the overall efficiency are found to agree with those of published work. Finally, although the antenna performance is quite frequency sensitive, experimental results indicate that high performance corrugated feeds can in fact be realized.
Problems related to large radiotelescopes can be grouped into two main categories: those connected with antenna structure and surface irregularities, and those related to feed design. At present the feed problems have received increasingly more attention because, although the antenna gain can be increased simply by increasing the reflector diameter, the high cost of building these large antennas makes them uneconomical for certain applications. On the other hand, an efficient feed can significantly increase the capability of a smaller but more accurately built reflector. For this reason this paper only discusses some aspects of the problem of designing efficient feed horns using corrugated waveguide. This type of waveguide structure can support hybrid modes, and its radiation pattern is axially symmetric with zero cross-polarization (Minnett and Thomas 1966). For completeness, problems related to both efficiency and signal-to-noise ratio will be examined. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present the theory and develop an algorithm associated with the exploration of a dual response surface system. The approach is to find conditions on a set of independent or "design" variables which maximize (or minimize) a "primary response" function subject to the condition that a "constraint response" function takes on some specified or desirable value. A method is outlined whereby a user can generate simple two dimensional plots to determine the conditions of constrained maximum primary response regardless of the number of independent variables in the system. He thus is able to reduce to simple plotting the complex task of exploring the dual response system. The procedure that is used to generate the plots depends on the nature of the individual univariate response functions. In certain situations it becomes necessary to apply the additional constraint that the located operating conditions are a certain "distance" from the origin of the independent variables (or the center of the experimental design). The methods derived and discussed in the paper are applicable only to quadratic response functions. [ABSTRACT FROM AUTHOR]

In many situations, approximation of a set of data by a polygonal curve is more advantageous than approximation by a polynomial. If the join points of the polygonal curve are known, the problem is quite simple. If, however, they are to be chosen in some expeditious fashion, considerable numerical difficulties can arise if the curve-fitting problem is approached directly. In this paper it is shown that dynamic programming offers a simple direct approach to the determination of an optimal fit. [ABSTRACT FROM AUTHOR]

In [1] a design, referred to as a Factor Sequencing Design (FSD), and analysis are presented for 2[sup p] factorial experiments where the factors are applied sequentially and where order of application may be of importance. The number of units required for an FSD is pi, which may be prohibitively large for p is greater than or equal to 4. This paper presents a method for fractionating the FSI) and gives specific designs with their associated analyses for p equal 3, 4, 5, and 6. [ABSTRACT FROM AUTHOR]

This paper deals with methods of "cluster analysis". In particular we attack the problem of exploring the structure of multivariate data in search of "clusters". The approach taken is to use a computer procedure to obtain the "best" partition of n objects into g groups. A number of mathematical criteria for "best" are discussed and related to statistical theory. A procedure for optimizing the criteria is outlined. Some of the criteria are compared with respect to their behavior on actual data. Results of data analysis are presented and discussed. [ABSTRACT FROM AUTHOR]

The designing of some multi-factor "analytical" studies of survey data is considered in this paper. It is assumed that, for each factor, there are two categories of interest and these are to be compared. The main objective is to allocate the sample so that the desired precision for the specified contrasts is obtained at minimum cost. It is assumed that one may sample independently in each of the sub-populations under investigation. A model is employed to facilitate designing and analyzing such a survey. We discuss the relevance of this model for "analytical studies," and a few examples are presented. Several survey objectives are explored, and an optimal allocation is obtained for each. Two, three and four-factor studies are considered explicitly. [ABSTRACT FROM AUTHOR]

It is claimed that the reasons for using matrices of derivatives, in appropriate situations, are as compelling as those for using matrices. This paper provides basic material for such use. Different types of matrix derivatives are defined and illustrated. Simple and easy techniques are then derived and are shown to be applicable to a considerable collection of matrix functions. Applications are made to such problems as establishing matrix integrals from scalar ones, determining maximum likelihood estimates for complex likelihood functions, optimizing matrix functions when there are matrices of side conditions, and evaluating the Jacobians of certain classes of transformations. The emphasis is on simplicity of derivation and on breadth of application. [ABSTRACT FROM AUTHOR]

Tins paper illustrates, through a special case, an effect of non-independent numerators on F-test's in an analysis of variance. Symmetrical balanced incomplete block designs are considered with "blocks" a random effect and no interaction. The joint density of the adjusted sums of squares is determined under the null hypothesis of no treatment effect. Given the result of testing for the block effect, the conditional probability of a Type I error when testing the null hypothesis concerning the treatment effect is evaluated for a number of designs. [ABSTRACT FROM AUTHOR]

The first section of this paper compares the theoretical production function framework of the current study with that of predecessors. The second section considers the development of theoretical micro-production and cost functions for water treatment plants. In economic theory the production function is a mathematical statement relating quantitatively the purely technological relationship between the output of a process and the inputs of the factors of production, the chief purpose of which is to display the possibilities of substitution between the factors of production to achieve a given output. The distinct kinds of goods and services which are usable in a production technology are referred to as the factors of production of that technology and for any set of inputs of these factors, the production function is interpreted to define the maximal output realizable there from. The production function is regarded here as a mathematical construction for some well defined production technology. The technology consists of a family of conceivable and feasible engineering arrangements, not restricted necessarily to particular realizations found in practice and possibly spanning historical changes in the application of the technology.

This paper deals with problems of response surface optimization in which the control variables and responses are subject to costs and constraints. Relationships between control variables and the cost or constraint functions are treated as additional response surfaces if explicit algebraic models are unavailable. Optimization methods are suggested which are based on gradient search and nonlinear programming techniques. To assure operating conditions within the specified constraint set a method based on feasible directions is used to control the search pattern. A scale-invariant gradient search method is suggested. Because it leads to an economical path to the maximum point the method has been dubbed "cheapest ascent." The selection of measurement scales for the control variables is also discussed. [ABSTRACT FROM AUTHOR]

Presents an optimization approach for machining for a fixed demand. Determination of the cutting conditions for minimum overall machining cost; Emphasis on the technological constraints related to each operation in machining; Economic effects of batch- and machine-idle time and of other disturbing events.