دانلود رایگان ترجمه مقاله حل مسئله برنامه ریزی تولید و مسئله زمان بندی در اسکله های بارگیری فله (نشریه الزویر 2016)

روش سلسله مراتبی برای حل مسئله برنامه ریزی تولید و مسئله زمان بندی در اسکله های بارگیری فله

A hierarchical approach to solve a production planning and scheduling problem in bulk cargo terminal

Abstract

The integration of planning and scheduling decisions is key to obtain an efficient and reliable production operation in a modern manufacturing and service company. In this work we propose a mathematical model for this integration, the model is defined considering logistic operations at bulk port, however is generic enough to be adapted to several situations. The integration takes place in a hierarchical scheme where the problems exchange data and they are solved through a commercial solver and heuristics. When scheduling is not feasible, capacity information is forwarded to production planning to adjust or indicate the use of new tasks. The model and algorithms are validated considering data from a real case. Computational results show the efficiency of the approach, producing strong bounds for large instances.

1 Introduction

In production systems, production planning and scheduling problems are critical for profitability of companies, correct use of resources and to meet deadlines. These problems are applicable in a broad range of sectors, such as the casting industry (Camargo, Mattiolli, & Toledo, 2012; de Souza, Jr, Bretas, & Ravetti, 2015), the food industry (Rocco & Morabito, 2014), and cargo transportation in port terminals (Robenek, Umang, & Bierlaire, 2014). Even though planning and scheduling belong to two different decision levels (from strategic to operational), there is a strong relation between them and there is extensive literature on solution models and strategies (Drexl & Kimms, 1997; Meyr & Mann, 2013; Phanden, Jain, & Verma, 2013; Ramezanian, SaidiMehrabad, & Teimoury, 2013). Published strategies can be divided into hierarchical and integrated approaches.

In a broad sense the production planning decides when and how many products must be produced, and the decisions are usually associated to cost trade-offs. Instead, scheduling problems take into account shop-floor settings and determine how the production must be executed. Their objectives are usually time-related. The independent optimization of these problems can clearly lead to non-optimal solutions, thus the need to combine the decisions levels. Integrated methods consider both problems simultaneously; that brings better solutions in exchange of a greater computational complexity. Another approach is a heuristic procedure, where in a hierarchical fashion the production planning and scheduling problems and solutions exchange data.

The problem motivating this research can be defined as follows: lets consider a variety of products arriving at a logistics terminal (supply), they need to be transferred to meet the demand or to a local storage area. To make this transfer, products need a feasible route of equipment. On the one hand, the planning problem must take decisions regarding when to move the material and where to move it. On the other hand, the scheduling problem deals with making the planning feasible, that is, determining a route of equipment to be use at each time period. Different routes have different capacities. They may share equipment creating conflicts when used during the same time period.

The focus of our work and the main contributions of this article are related to the integrated solution methodology to deal with a complex problem with real size instances. In this manuscript, we propose the use of a hierarchical framework to solve a production planning and scheduling problem for the delivery of products. The methodology uses a combination of heuristics and mathematical formulations; the novelty of the method is on the combination of this algorithms to deal with the trade-off between medium and short term decisions. Moreover, based on the scheduling solution additional constraints are generated to strengthen the production planning. To link this problem with two levels of information we use the capacity of the routes.

In addition, to this contribution, the hierarchical framework, and a mathematical model are built to address a real storage and transportation problem, that occurs in a Brazilian bulk terminal. This problem is also common in iron ore port terminals and has not been fully investigated in the literature. The experiments are validated considering data from a real case and the computational results show the effectiveness of algorithms and model.

The remainder of this article is structured as follows: Section 2 presents the literature review. Section 3 defines the problem on which a mathematical programming model is based. Section 4 presents some sets and variables used in the mathematical formulation (the complete model is available in the appendix). Section 5 discusses the solution strategy applied and the main algorithms developed. Section 6 is dedicated to computational results and the manuscript ends with conclusions and future research directions.