scholarly journals PEMROGRAMAN LINEAR INTEGER DENGAN ENAM VARIABEL ORIENTASI KARGO UNTUK MASALAH MINIMISASI BIAYA PEMUATAN MULTI-KONTAINER

2020 ◽  
Vol 15 (3) ◽  
pp. 162-168
Author(s):  
Dian Pratiwi Sahar ◽  
Mohammad Thezar Afifudin

Penelitian ini bertujuan untuk mengembangkan model matematika untuk masalah minimisasi biaya pemuatan multi-kontainer dengan enam variabel orientasi kargo. Masalah ini dirumuskan sebagai model pemrograman linier biner integer untuk meminimalkan biaya. Faktor-faktor yang dipertimbangkan dalam formulasi termasuk alokasi kargo, lokasi kargo, hubungan kargo, dan orientasi kargo. Sedangkan, biaya yang dipertimbangkan termasuk biaya muatan volume kontainer ke kargo dan biaya transportasi kargo ke kontainer. Validasi model dilakukan melalui percobaan numerik pada ukuran kecil kargo dan kontainer. Hasil penelitian menunjukkan bahwa model dengan konsep orientasi kargo yang dikembangkan dapat menyelesaikan masalah sesuai dengan parameter numerik yang diberikan. Abstract[Integer Linear Programming with Six Cargo Orientation Variables for Multi-Container Loading Cost Minimization Problem] This research aims to develop the mathematic model for multi-container loading cost minimization problems with six cargo orientation variables. The problem is formulated as a binary integer linear programming model to minimize costs. The factors considered in the formulation include cargo allocation, cargo location, cargo relations, and cargo orientation. Whereas, the costs considered include the container volume load cost to cargo and the cargo transport cost to the container. Model validation is performed through numerical experiments on the small size of cargo and containers. The results show that the model with developed cargo orientation concept can solve the problem according to the given numerical parameters.Keywords: integer programming; cargo orientation; container loading; cost minimization

Logistics ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 19
Author(s):  
Aspasia Koutsokosta ◽  
Stefanos Katsavounis

Quantifying the benefits of construction supply chain management through prescriptive models is a challenging and fast-growing research area that still lacks standardized optimization models with full integrative potential. In response to the needs and the peculiarities of the construction industry, this paper proposes an innovative model that merges temporal and project-based supply chains into a sustainable network with repetitive flows, large scope contracts, strategic alliances and economies of scale. It is a dynamic mixed-integer linear programming model for cost minimization of a three-echelon supply chain serving multiple sites with multiple products over a time horizon. Its novelty lies in yielding optimal decisions on network design, product quantities to be purchased and transported, shipments and inventory levels in all echelons under any logistics system in a multi-period, multi-product and multi-project environment with discount schemes and strategic preferences. The model is general enough to be implemented by any general contractor acting as a system integrator but also allows customization with logical constraints. All these features constitute an innovative, versatile and flexible managerial decision making tool. Model implementation is based on a spreadsheet optimization software and is followed by post-solution analysis, sensitivity analysis and multiple parameterized optimizations.


2021 ◽  
Vol 11 (1) ◽  
pp. 232-240
Author(s):  
Alexander V. Khorkov ◽  
Shamil I. Galiev

Abstract A numerical method for investigating k-coverings of a convex bounded set with circles of two given radii is proposed. Cases with constraints on the distances between the covering circle centers are considered. An algorithm for finding an approximate number of such circles and the arrangement of their centers is described. For certain specific cases, approximate lower bounds of the density of the k-covering of the given domain are found. We use either 0–1 linear programming or general integer linear programming models. Numerical results demonstrating the effectiveness of the proposed methods are presented.


2020 ◽  
Vol 12 (3) ◽  
pp. 1131
Author(s):  
Wenliang Zhou ◽  
Xiaorong You ◽  
Wenzhuang Fan

To avoid conflicts among trains at stations and provide passengers with a periodic train timetable to improve service level, this paper mainly focuses on the problem of multi-periodic train timetabling and routing by optimizing the routes of trains at stations and their entering time and leaving time on each chosen arrival–departure track at each visited station. Based on the constructed directed graph, including unidirectional and bidirectional tracks at stations and in sections, a mixed integer linear programming model with the goal of minimizing the total travel time of trains is formulated. Then, a strategy is introduced to reduce the number of constraints for improving the solved efficiency of the model. Finally, the performance, stability and practicability of the proposed method, as well as the impact of some main factors on the model are analyzed by numerous instances on both a constructed railway network and Guang-Zhu inter-city railway; they are solved using the commercial solver WebSphere ILOG CPLEX (International Business Machines Corporation, New York, NY, USA). Experimental results show that integrating multi-periodic train timetabling and routing can be conducive to improving the quality of a train timetable. Hence, good economic and social benefits for high-speed rail can be achieved, thus, further contributing to the sustained development of both high-speed railway systems and society.


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