Vaccination against infectious disease is hailed as one of the great achievements in public health. However, the United States Recommended Childhood Immunization Schedule is becoming increasingly complex as it is expa...
详细信息
Vaccination against infectious disease is hailed as one of the great achievements in public health. However, the United States Recommended Childhood Immunization Schedule is becoming increasingly complex as it is expanded to cover additional diseases. Moreover, biotechnology advances have allowed vaccine manufacturers to create combination vaccines that immunize against several diseases in a single injection. All these factors are creating a combinatorial explosion of alternatives and choices (each with a different cost) for public health policy makers, pediatricians, and parents/guardians (each with a different perspective). The General Vaccine Formulary Selection Problem (GVFSP) is introduced to model general childhood immunization schedules that can be used to illuminate these alternatives and choices by selecting a vaccine formulary that minimizes the cost of fully immunizing a child and the amount of extraimmunization. Both exact algorithms and heuristics for GVFSP are presented. A computational comparison of these algorithms and heuristics is presented for the 2006 Recommended Childhood Immunization Schedule, as well as several randomly generated childhood immunization schedules that are likely to be representative of future childhood immunization schedules. The results reported here provide both fundamental insights into the structure of the GVFSP models and algorithms and practical value for the public health community.
Recently there has been considerable interest in the average-case performance of heuristics. This paper pursues that interest, where it concerns sequencing and packing problems. In particular, we survey the methods th...
详细信息
Recently there has been considerable interest in the average-case performance of heuristics. This paper pursues that interest, where it concerns sequencing and packing problems. In particular, we survey the methods that have been used to obtain formal probabilistic analyses of heuristics for makespan scheduling and one-dimensional bin packing. In so doing, we present many of the key results in these research areas.
In this paper we present a heuristic method, based on Lagrangian relaxation, for multilevel lot-sizing when there is a single bottleneck facility. A series of Lagrangian relaxations (one for each item in the product s...
详细信息
In this paper we present a heuristic method, based on Lagrangian relaxation, for multilevel lot-sizing when there is a single bottleneck facility. A series of Lagrangian relaxations (one for each item in the product structure) is imbedded in a branch and bound procedure. The objective is to find a production schedule that fits within available capacity at minimum cost. The method has two solution phases, dual and primal. In the dual phase of the procedure, implied costs of setups and production are determined based on a tentative schedule. The primal phase is repeated with these new prices and we iterate to reach a good solution.
In this survey paper we discuss the development of the simple assembly line balancing problem (SALBP); modifications and generalizations over time; present alternate 0-1 programming formulations and a general integer ...
详细信息
In this survey paper we discuss the development of the simple assembly line balancing problem (SALBP); modifications and generalizations over time; present alternate 0-1 programming formulations and a general integerprogramming formulation of the problem; discuss other well-known problems related to SALBP; describe and comment on a number of exact (i.e., optimum-seeking) methods; and present a summary of the reported computational experiences. All models discussed here are deterministic (i.e., all input parameters are assumed to be known with certainty) and all the algorithms discussed are exact. The problem is termed “simple” in the sense that no “mixed-models,” “subassembly lines,” “zoning restrictions,” etc. are considered.
The most commonly used penalty in branch and bound approaches to integerprogramming is the Driebeek–Tomlin penalty. It has been used successfully in solving fixed cost linear programs by Kennington and Unger and by ...
详细信息
The most commonly used penalty in branch and bound approaches to integerprogramming is the Driebeek–Tomlin penalty. It has been used successfully in solving fixed cost linear programs by Kennington and Unger and by Barr, Glover and Klingman. It is well known that the Driebeek–Tomlin penalty can be derived from a Lagrangean relaxation of the integerprogramming problem. We show, however, that the Lagrangean relaxation for fixed cost problems not only yields the Driebeek–Tomlin penalty, but two penalties which sometimes dominate it. We show the strength of the new penalties by solving a series of text problems and comparing the number of nodes generated on the branch and bound tree and the total computer time needed to solve each problem.
The branch and bound principle has long been established as an effective computational tool for solving mixed integer linear programming problems. This paper investigates the computational feasibility of branch and bo...
详细信息
The branch and bound principle has long been established as an effective computational tool for solving mixed integer linear programming problems. This paper investigates the computational feasibility of branch and bound methods in solving convex nonlinear integerprogramming problems. The efficiency of a branch and bound method often depends on the rules used for selecting the branching variables and branching nodes. Among others, the concepts of pseudo-costs and estimations are implemented in selecting these parameters. Since the efficiency of the algorithm also depends on how fast an upper bound on the objective minimum is attained, heuristic rules are developed to locate an integer feasible solution to provide an upper bound. The different criteria for selecting branching variables, branching nodes, and heuristics form a total of 27 branch and bound strategies. These strategies are computationally tested and the empirical results are presented.
The coach of an intercollegiate women's gymnastics team must choose a lineup to maximize the potential total team score by optimally assigning gymnasts to the different events. Manual computation of total scores p...
详细信息
The coach of an intercollegiate women's gymnastics team must choose a lineup to maximize the potential total team score by optimally assigning gymnasts to the different events. Manual computation of total scores possible from several lineups is burdensome. A bivalent integerprogramming formulation was used to establish the competitive lineup for intercollegiate matches at Utah State.
Given n items, each having a weight wi, and a container of capacity W, the Subset-Sum Problem (SSP) is to select a subset of the items whose total weight is closest to, without exceeding, W.
Given n items, each having a weight wi, and a container of capacity W, the Subset-Sum Problem (SSP) is to select a subset of the items whose total weight is closest to, without exceeding, W.
An important, recurring problem in statistics involves the determination of strata boundaries for use in stratified sampling. This paper describes a practical method for stratifying a population of observations based ...
详细信息
An important, recurring problem in statistics involves the determination of strata boundaries for use in stratified sampling. This paper describes a practical method for stratifying a population of observations based on optimal cluster analysis. The goal of stratification is constructing a partition such that observations within a stratum are homogeneous as defined by within-cluster variances for attributes that are deemed important, while observations between strata are heterogeneous. The problem is defined as a deterministic optimization model with integer variables and is solved by means of a subgradient method. Computational tests with several examples show that the within-strata variances and thus the accompanying standard errors can be substantially reduced. Since the proposed model strives to minimize standard error, it is applicable to situations where a precise sample is essential, for example, microeconomic simulation studies.
An approach for developing heuristic problem-solving procedures for solving the types of operational problems with significant combinatorial components that commonly occur in production and distribution systems is dem...
详细信息
An approach for developing heuristic problem-solving procedures for solving the types of operational problems with significant combinatorial components that commonly occur in production and distribution systems is demonstrated with a variation of the well-known one-dimensional cutting stock problem. The primary elements of the approach are identifying important solution characteristics, developing a sequential solution procedure, selecting the program control parameters, and developing a multiple-pass feature to obtain improved solutions.
暂无评论