Showing papers on "Heuristic published in 1973"

A Simple Continuous Review Deterministic One-Warehouse N-Retailer Inventory Problem

Abstract: A one-warehouse N-retailer deterministic inventory system is examined. The objective is to determine the stocking policy which minimizes average system cost per unit time over the infinite time horizon. Necessary properties of an optimal policy are derived, and optimal solutions for the one-retailer and N identical retailer problems are given. Heuristic solutions for the general problem are suggested, tested against analytical lower bounds and, on the basis of these tests, found to be near optimal.

The avoidance of (relative) catastrophe, heuristic competence, genuine dynamic weighting and computational issues in heuristic problem solving

Abstract: To solve difficult problems heuristically, requires detailed attention to computational efficiency This paper describes how a heuristic problem solving system, HPA, attempts to find a near optimal solution to the traveling salesman problem A critical innovation over previous search algorithms is an explicit dynamic weighting of the heuristic information The heuristic information is weighted inversely proportional to its depth in the search tree -- in consequence it produces a narrower depth first search than traditional weightings At the same time, dynamic weighting retains the catastrophe protection of ordinary branch and bound algorithms

A Cost-Oriented Approach to Stochastic Line Balancing1

Abstract: This paper presents a new heuristic for balancing paced assembly lines involving tasks which exhibit significant time variations Labor and incompletion costs are explicitly considered in grouping tasks into work assignments to achieve a near minimum cost line design The procedure is computationally attractive because its calculations are comparably efficient to those of heuristics which consider task times deterministically

A Heuristic Relaxation Method for Nonlinear Mapping in Cluster Analysis

Abstract: A relaxation method mapping high-dimensional sample points to low-dimensional sample points is discussed. This method tries to preserve the local interdistance of sample points. Some special heuristics have been introduced to handle the difficulty arising from a large amount of data. Experimental results with handwritten character data and Iris data show that the method runs fast, converges rapidly, and requires a small amount of memory space.

Balancing Stochastic Assembly Lines

Abstract: This paper is concerned with balancing continuous assembly lines with stochastic work elements, The primary problem is defined as follows: “Given an initial balance, a cycle time, normally distributed work element times with given means and variances, and a precedence graph, rearrange the work elements such that the probability of one or more stations exceeding the cycle time is minimized.” Four solution procedures, Trade and Transfer, Branch and Bound, Heuristic Branch and Bound and BABTAT are evaluated.

Automated exploration of the design space for register transfer (RT) systems

Abstract: A Design Automation System for the RT level of design is described. The System explores the design space by finding alternative implementations for a user given behavioral specification. The alternative solutions are obtained by transformations on a graph model. These transformations effect trade-offs between the cost of the hardware and the speed of the algorithm. Heuristic routines are used to reduce the design space by exploring only those alternatives whose characteristics approach a user given set of goals.

Set of test problems for the minimum length connection networks

Abstract: The problem of finding the shortest network connection given set of points is often referred to as the Problem of Steiner. The applications of this problem can be found in various engineering fields, typically in the design of telephone networks, in the planning of highway systems or in the design of large mining operations. In the present state of art, for 20 given points or more, one must use a heuristic method to obtain at least a suboptimum solution in a reasonable time.

A Heuristic Approach to Selecting Sales Regions and Territories

Abstract: It is argued that the typical method of selecting sales regions and territories can produce unequal allocations of work load. This paper presents a set of procedures for evaluating a sales region configuration and then successively adjusting the boundaries until work load is uniformly allocated. The logic and computation are both straightforward. The great advantage is that the procedure allows the manager to suggest which boundary adjustments he wishes to make next. In this way he has complete control of the process. A discussion of a particular application is presented.

A Heuristic Search Procedure for Estimating a Global Solution of Nonconvex Programming Problems

Abstract: This paper develops a penalty function and several techniques for searching nonconvex areas for a global optimum and presents numerical results for several small though very difficult nonconvex programming problems. No proofs of convergence have been obtained, nor has it been possible to categorize the types of problems for which these techniques are successful.

Information theory applied to the conversion of decision tables to computer programs

Abstract: Using ideas from information theory, this paper develops a heuristic algorithm that converts a limited entry decision table to a tree structured computer program with near minimum average processing time. The method is applicable to any limited entry decision table and does not require that actions have single rules or that the cost of testing conditions be equal. It is thus more general than the previously published heuristic algorithms. Compared to the optimal algorithm of Reinwald and Soland, this algorithm is easy to code and takes a much smaller translation time; it is thus felt that it is more useful in practice. The algorithm is well suited for manual conversion of decision tables to flowcharts.

Heuristic Methods for Mechanically Deriving Inductive Assertions.

Abstract: Current methods f o r mechanical program v e r i f i c a t i o n r e q u i r e a complete p red i ca te s p e c i f i c a t i o n on each l o o p . Because t h i s i s ted ious and e r r o r p r o n e , producing a program w i t h complete, c o r r e c t p red i ca tes i s reasonably d i f f i c u l t and would be f a c i l i t a t e d by machine ass i s t ance . This paper d iscusses h e u r i s t i c methods f o r mechanica l ly d e r i v i n g loop p r e d i ­ cates from t h e i r boundary c o n d i t i o n s and f o r mechanica l ly comple t ing p a r t i a l l y s p e c i f i e d loop p r e d i c a t e s . I n t r o d u c t i o n Mechanical v e r i f i c a t i o n o f program cor rec tness i s d e s i r a b l e and p o s s i b l e . 1 Given a program, a f i r s t o r d e r ax io tna t i za t i on o f i t s semant ics, and p red i ca tes on the i n p u t , o u t p u t , and each l o o p , v e r i f i c a t i o n o f the ou tpu t p r e d i c a t e i s a mechanical p rocess , ( c . f . [2] and [3] f o r recent su r veys ) . I npu t and ou tpu t p red i ca tes are necessary and n a t u r a l f o r a programmer to supp ly . However, comple te ly s p e c i f y i n g the p red i ca tes on loops i s t e d i o u s , e r r o r p r o n e , and redundant . I t i s ted ious due to the l a r g e amount o f s te reo typed d e t a i l r e q u i r e d . I t i s e r r o r p r o n e * p a r t l y because of the tedium and p a r t l y because the n o t a t i o n i s l ess n a t u r a l than t h a t f o r p rocedura l s t eps . I t i s redundant s ince the p red i ca tes repeat i n f o r m a t i o n which i s man i fes t in the program. The purpose o f t h i s paper i s to show t h a t loop p red i ca tes can be de r i ved mechan ica l l y * * and t h a t p a r t i a l l y s p e c i f i e d loop p red i ca tes can be completed mechan ica l l y . *An example may lend some weight of exper ience . In h i s t h e s i s 4 , K ing presents n ine programs submi t ted to the v e r i f i e r ; the most complex o f these (Example 9) has an i n c o r r e c t loop p r e d i ­ c a t e , i . e . the i n d u c t i v e a s s e r t i o n i s too weak to be c o n s i s t e n t o r to imp ly the des i red ou tpu t p r e d i c a t e . (Since the theorem prover r e j e c t e d the loop p r e d i c a t e due to an i n a b i l i t y to handle m u l t i p l e q u a n t i f i c a t i o n , the p r e d i c a t e e r r o r was over looked . ) * * I n one sense, t h i s i s t r i v i a l . A l l w e l l formed p r e d i c a t e expressions f o r each loop can be enumerated and p roo fs of co r rec tness d o v e t a i l e d u n t i l one succeeds. I f every v a l i d theorem o f the sub jec t domain i s p rovab le , t h i s w i l l e v e n t u a l l y v e r i f y the program; o the rw i se , mechanical v e r i f i c a t i o n i s no t poss ib l e i n g e n e r a l . Such a procedure i s , however, compu ta t i ona l l y i n t r a c t i b l e . tA l so a t Harvard U n i v e r s i t y , Cambridge, Mass. E lspas , Green, L e v i t t , and Wald inger 5 have independent ly worked on t h i s problem us ing d i f f e r e n c e equat ions as an a i d to s p e c i f y i n g a s s e r t i o n s . Cooper has p r e v i o u s l y s t u d i e d the problem and observed t h a t an i n d u c t i v e a s s e r t i o n can be ob ta ined by hand by c o n s t r u c t ­ i n g the f i r s t few terms i n the loop expansion, which g e n e r a l l y shows what the i n f i n i t e un ion must be . Our method uses a d i f f e r e n t approach. To generate loop p red i ca tes where none are s u p p l i e d , the ou tpu t p red i ca te i s dragged backward through the program and mod i f i ed when pass ing through program u n i t s , to produce t r i a l loop p r e d i c a t e s . T r i a l l oop p red i ca tes which are loop i n c o n s i s t e n t are mod i f i ed accord ing t o va r ious h e u r i s t i c s , t o generate b e t t e r t r i a l p r e d i c a t e s . Hence, i t i s a l so p o s s i b l e to accept a programmer-suppl ied i n d u c t i v e a s s e r t i o n which g ives the " e s s e n t i a l " idea o f some loop and mechanica l ly f i l l i n the d e t a i l s to a r r i v e a t a complete, c o r r e c t loop p r e d i c a t e . Many of the h e u r i s t i c s are domain s p e c i f i c , t h i s paper uses i n t e g e r s and i n t ege r a r rays as the sub jec t domain. The paper i s d i v i d e d i n t o f i v e s e c t i o n s . Sec t ion 2 i l l u s t r a t e s our approach w i t h two s imple examples. Sec t ion 3 d iscusses the genera l method, domain-independent h e u r i s t i c s , and h e u r i s t i c s s p e c i f i c t o the i n t e g e r s . Sec t ion 4 t r e a t s a number of complex examples to show how the h e u r i s t i c s are used and e x h i b i t t h e i r c o u p l i n g . Sec t ion 5 d iscusses implementat ion and a p p l i c a t i o n o f t h i s method. N o t a t i o n . Throughout, a s imple f l o w c h a r t language i s used. The i n p u t p red i ca te i s denoted by o; the ou tpu t p red i ca te by w. Unprimed (primed) v a r i a b l e s and p red ica tes denote values and p red i ca tes on these va lues be fo re ( a f t e r ) c o n t r o l f lows through a se t o f f l o w c h a r t boxes. The t r a n s f o r m a t i o n due to a f l o w c h a r t path A ^ i A £ 2 ' * A i n i s denoted by 6 { i i , i , , . . . £ ) . ' l ' 2

Constructing Monothetic and Polythetic Typologies By the Heuristic Method

Abstract: Past students of heuristic types such as the ideal or constructed types have often proposed that empirical cases be studied by comparison with the heuristic type. However, they have provided no spe...

The Effectiveness of Three Heuristic Rules for Job Sequencing in a Single Production Facility

Abstract: This paper examines the effectiveness of three heuristic rules used in production sequencing where the objective is to minimize the downtime due to setup changes. The effectiveness of these heuristic rules was evaluated under various conditions of job size and setup time distribution. The results of this analysis indicate that job conditions do affect the effectiveness of these three rules.

A Heuristic Method for Finding Most Extrema of a Nonlinear Functional

Abstract: A heuristic search is described which has the aim of finding practically all the extrema of a given nonlinear functional. A standard unimodal descent algorithm is employed for finding individual extrema. This basic algorithm is applied repeatedly using various computed initial points and starting directions. Through the additional use of several learning cycles most of the available extrema can be found. Numerical experiments indicate that the method is very efficient for the functionals of dimensions 15-20 with 20-25 extrema.

A rationale for heuristic program selection and evaluation

Abstract: In the past, great claims have been set forth as to the potential of the heuristic procedure or "heuristic programming," References 1 and 2. As early as 1958 Simon and Newell, Reference 2, wrote of "Heuristic Problem Solving: The Next Advance in Operations Research." However, and this is strictly the opinion of the authors (although it is shared by most others we have discussed the matter with), rather than seeing a relative increase in heuristic program solution techniques in the literature, the converse appears to be true. Most of the journals dealing with operations research, management science, industrial engineering, and related fields have evolved (or perhaps dissolved, depending on one's point of view) into journals of mathematics, or perhaps abstract mathematics. The fundamental idea of engineering as being directed toward real world applications often seems to have been lost. As a result, we (industrial engineers/operations researchers) are now caustically described as pseudo-mathematicians, and the field has been defined as the "science of providing elegant solutions to trivial problems." OR has even been credited with such things as our poor performance and defeats in the Indo-China war, Reference 5, cost overruns on defense contracts and so on. Such criticism comes from both outside and within our profession, References 3, 4, 5.

Heuristic decision policies for the control of reversible traffic links

Abstract: Mathematical models of the delays incurred in a traffic link with reversible lanes, as a function of demands for service and allocation decisions, are constructed assuming that the state of the operation is reviewed periodically. There is a penalty associated with each allocation change that is manifested as a loss of capacity. Heuristic algorithms are derived that enable the determination of decision policies that minimize the delay per vehicle during some horizon. The first phase of the determination is performed upon a basic model, in which the reversal penalties are ignored, and results in a sequence of optimal periodwise decisions. This policy is then subjected to a second phase, performed upon the lost time model, in which reversal penalties are included. Progressively better policies are generated in this phase according to the heuristic notion that an optimal policy does not differ much from the policy obtained in the first phase. The solution of the models is illustrated in a case study using act...

Reaction path synthesis strategies

Abstract: A system is offered for the mathematical representation of the functional and structural features of organic molecules and their reactions. Two basic synthesis strategies, an antithetic method anda synthetic method, are defined and compared. The use of heuristic information in guiding synthesis is evaluated. A synthetic method which uses dynamic programming is presented and applied to the synthesis of bihelical DNA. Possible extensions to other classes of compounds are presented.

A note on sub-expression ordering in the execution of arithmetic expressions

Abstract: A counterexample to the supposed optimality of an algorithm for generating schedules for trees of tasks with unequal execution times is presented. A comparison with the “critical path” heuristic is discussed.

Heuristic Selection of Advanced Bases for a Class of Linear Programming Models

Abstract: This paper describes a procedure for selecting a starting basis for a class of large linear programming models. This class, a generalization of the transportation problem, is the product of a matrix generator described elsewhere. The procedure is joined to the matrix-generator process and uses structural criteria and implicit knowledge of the model being generated to assess the attractiveness of vectors for an optimal solution. Additionally, it allows the analyst to describe, through a set of multipliers, the general features of the expected optimal solution. The multipliers are employed heuristically in conjunction with the other criteria to select a set of vectors, both logical and structural, for submission to a standard mathematical programming computational system as a starting basis. Examples of applications of the basis selector and possible extensions are presented.

Scheduling of computer programs for optimal machine utilization

Abstract: This paper discusses the problem of developing schedules for the execution of computer programs in a batch oriented multiprogramming environment. An approximate approach to the problem is developed by heuristically reducing the dimensionality of the problem to a sequential optimization problem. The superiority of this heuristic criterion over five other commonly used criteria is shown. A numerical example is given.

A Heuristic Program to Discover Syntheses for Complex Organic Molecules.

Abstract: : Organic chemical synthesis is found to be a suitable problem for developing machine intelligence. The present article aims to describe the program organization as a heuristic search, the design of the Problem Solving Tree and the search procedures in condiserable detail. Examples of syntheses discovered and the problem solving tree developed are given. The programs are written mostly in PL1(F) applicable to an IBM 360/67 and the timings (batch mode) indicate that it is a fast and efficient practical systems. (Modified author abstract)

Tan-Like State Assignments ror Synchronous Sequential Machines

Abstract: Recently, Tan developed a heuristic state assignment algorithm for asynchronous sequential machines. In this paper a state assignment algorithm based on Tan's is developed for synchronous sequential machines. It shares with Tan's algorithm the advantages of simplicity of execution and economy of logic elements in the resulting realizations.