ORiON Pub Date : 2014-11-17 DOI: 10.5784/30-2-143

Jan A. Oberholzer, J. Hattingh, T. Steyn

引用次数: 0

In-season retail sales forecasting using survival models 利用生存模型预测应季零售销售

ORiON Pub Date : 2014-11-17 DOI: 10.5784/30-2-153

M. Hattingh, DW Uys

引用次数: 3

An interior-point method for the Cartesian P * ( Κ )-linear complementarity problem over symmetric cones 对称锥上笛卡尔P * (Κ)-线性互补问题的内点法

ORiON Pub Date : 2014-06-03 DOI: 10.5784/30-1-140

B. Kheirfam

引用次数: 8

Decision support for Foodbank South Africa 为南非食品银行提供决策支持

ORiON Pub Date : 2014-06-03 DOI: 10.5784/30-1-142

Nm Watson, T. Stewart, L. Scott

引用次数: 0

Application of the multi-objective cross-entropy method to the vehicle routing problem with soft time windows 多目标交叉熵方法在带软时间窗车辆路径问题中的应用

ORiON Pub Date : 2014-06-03 DOI: 10.5784/30-1-127

C. Hauman, J. Bekker

引用次数: 4

Editorial to Volume 30(1) 第30卷(1)社论

ORiON Pub Date : 2014-06-03 DOI: 10.5784/30-1-519

S. E. Visagie

引用次数: 0

Methods of OR: A new graduate course 手术方法:一门新的研究生课程

ORiON Pub Date : 2014-01-19 DOI: 10.5784/19-0-178

P. Fourie, I. Nieuwoudt, Jh van Vuuren

引用次数: 1

A partitioning scheme for solving the 0-1 knapsack problem 求解0-1背包问题的分划方案

ORiON Pub Date : 2014-01-01 DOI: 10.5784/19-0-179

M. Kruger, J. Hattingh

{"title":"A partitioning scheme for solving the 0-1 knapsack problem","authors":"M. Kruger, J. Hattingh","doi":"10.5784/19-0-179","DOIUrl":"https://doi.org/10.5784/19-0-179","url":null,"abstract":"The application of valid inequalities to provide relaxations which can produce tight bounds, is now common practice in Combinatorial Optimisation. This paper attempts to complement current theoretical investigations in this regard. We experimentally search for \"valid\" equalities which have the potential of strengthening the problem's formulation. Recently, Martello and Toth included cardinality constraints to derive tight upper bounds for the 0-1 Knapsack Problem. Encouraged by their results, we partition the search space by using equality cardinality constraints. Instead of solving the original problem, an equivalent problem, which consists of one or more 0-1 Knapsack Problem with an exact cardinality bound, is solved. By explicitly including a bound on the cardinality, one is able to reduce the size of each subproblem and compute tight upper bounds. Good feasible solutions found along the way are employed to reduce the computational effort by reducing the number of trees searched and the size of the subsequent search trees. We give a brief description of two Lagrangian-based Branch-and-Bound algorithms proposed in Kruger for solving the exact cardinality bounded subproblems and report on results of numerical experiments with a sequential implementation. Implications for and strategies towards parallel implementation are also given.","PeriodicalId":30587,"journal":{"name":"ORiON","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74974311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Optimising investment performance through international diversification 通过国际多元化优化投资业绩

ORiON Pub Date : 2014-01-01 DOI: 10.5784/15-0-414

J. Swart

引用次数: 2

Wisselboustelsels in die Swartland

ORiON Pub Date : 2014-01-01 DOI: 10.5784/14-0-420

H. Kock, Stephan E. Visagie

{"title":"Wisselboustelsels in die Swartland","authors":"H. Kock, Stephan E. Visagie","doi":"10.5784/14-0-420","DOIUrl":"https://doi.org/10.5784/14-0-420","url":null,"abstract":"In the Swartland region farmers do not plant wheat exclusively. There are a lot of reasons for this. The main reason is that farmers who plant only one crop will end up with a situation where they will have to buy so much fertiliser that they would not be able to make any money. Every crop influences the crops on the same land later on. It is up to the farmer to decide what the influence will be. That means it is up to the farmer to decide what crop to plant on what land. The farmer ends up rotating a certain number of crops on his land. This rotation of crops is called a rotary crop system. In this situation arises the problem of what sequence of crops should be planted to ensure an optimal income to the farmer without exhausting the land. The problem could be solved by means of linear programming (LP). This problem, however, seem to get very large as the number of crops as well as the number of years over which the problem is solved is increased. By assuming that the influence of crops are only for three years and by restricting the number of years over which the problem is solved the problem is greatly reduced. If we look at the dual of the problem we find a further reduction. The solution of the dual problem also leads to the formulation of strategies. If we formulate the problem by means of the above mentioned strategies the problem reduces to a linear programming problem with only on constraint (which is the knapsack problem). The solution of this knapsack problem with help of a little game theory is then used in a computer program to assist farmers in deciding which crops to plant.","PeriodicalId":30587,"journal":{"name":"ORiON","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75739157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

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