OPTIMASI PERENCANAAN LEVEL PRODUCTION UNTUK PERISHABLE PRODUCT MENGGUNAKAN INTEGER LINEAR PROGRAMMING (Studi Kasus : KUD Dau Malang)

Abstrak Susu pasteurisasi merupakan salah satu produk yang dihasilkan Unit KUD Dau Malang. Perusahaan memproduksi susu pasteurisasi dalam kemasan 140 cc dan 200 cc dengan menggunakan sistem produksi make to stock. Perencanaan jumlah produksi pada perishable product yang mempunyai masa umur  relatif pendek dengan permintaan berfluktuasi akan menghadapi resiko kerugian akibat produk rusak sebelum terjual. Perusahaan dihadapkan pada pilihan overstock ketika produksi melebihi permintaan dan shortage ketika jumlah permintaan melebihi jumlah produksi. KUD Dau memiliki batas penyimpanan produk hingga 2 hari, dan ketika produk masih belum terjual pada hari kedua maka barang tersebut akan dibuang.Penelitian ini mempergunakan pendekatan Integer Linear Programming untuk meminimalir total biaya akibat adanya ketidaksesuaian perencanaan produksi. Pendekatan Integer Linear Programming yang diformulasikan dengan satufungsi tujuan untuk meminimasi biaya yang meliputi biaya overstock, shortage dan scrapped.dan dibatasi beberapa fungsi kendala berkaitan dengan variabel overstock, shortage, scrapped dan semua variabel yang terdapat pada persamaan dalam bentuk bilangan non-negatif. Kata Kunci:Production planning, level production, perishable product, cost minimization, integer linear programming

Optimizing planning decisions in the fruit supply chain

La agro-indústria xilena ha experimentat un augment constant d'exportacions de fruita processada en la darrera dècada, arribant a un augment del 107% en volum total i 185% en valor. Aquest creixement significa que la cadena de subministrament de fruita fresca, ja sigui per a conserva, deshidratats, congelat i fresc de fruites o sucs, requereix suport per fer gestió cada vegada més eficient. Fins ara, alguns problemes relacionades directament amb la necessitat de millorar la competitivitat del sector no han estat encara tractats. En els últims anys els costos de producció han augmentat degut principalment a l'escassetat de mà d'obra i la mala qualitat de la fruita fresca. Això fa que millorar l'eficiència de cadena de subministrament i per tant la competitivitat agroindústria, requereixi de noves eines que serveixin de suport a la presa de decisions a la cadena de subministrament de fruita fresca. En aquest context, l'objectiu general d'aquesta recerca era desenvolupar un conjunt d'eines per donar suport a les decisions tàctiques de la cadena de subministrament de la fruita i millorar la gestió de compres, de les cambres frigorífiques i el transport. Tres importants contribucions es fan en aquest treball de recerca. La primera d'elles té a veure amb l'estat de l'art de les cadenes de subministrament, revisant els models d'optimització aplicats a les cadenes de subministrament de fruita fresca. La segona consisteix a proporcionar quatre eines per recolzar les decisions tàctiques de les cadenes de subministrament de fruita fresca, en concret, tres models matemàtics per a l'optimització de les decisions que donen suport a la selecció de productors i la compra de fruita fresca, el seu posterior emmagatzematge i transport i la proposta d'un model per a la gestió de cambres frigorífiques. Una tercera aportació és la proposta d'un sistema de suport a la presa de decisió (DSS), permeti la transparència del coneixement dels models anteriors al sector per al seu us pràctic. Destacar el valor addicional del treball a l'haver aplicat els models a casos reals. Així, tots el models proposats van ser validats amb l'ajut de l'agroindústria de la regió centre-sud de Xile que tenien problemes amb la seva cadena de subministrament.The Chilean agro-industry has experienced a steady increase of industrialized fruit exports over the last decade, reaching a total volume increase of 107% and 185% in value. This growth means that the fresh fruit supply chain, either for preserved, frozen, dehydrated, fresh fruit or juices, requires support in order to make management increasingly more efficient. So far, some problems directly related to the need to improve the sector´s competitiveness have not yet been addressed. In the last few years production costs have risen mainly due to labor shortage and poor quality of raw material (fresh fruit). That is why, improving the supply chain efficiency and thus the agro-industry competitiveness, particularly in the center-south region of the country, requires new tools that could support decisions making regarding the fresh fruit supply chain. Within this context, the general objective of this research was to develop a set of tools aiming to support tactical decisions that could enhance management of fresh fruit purchasing, cold storage, transport, and opening of cold chambers. Three important contributions are made in this research study. The first one has to do with the state-ofthe- art of supply chains management, by reviewing optimization models applied to fresh fruit supply chains. The second one consists in providing four tools to support tactical decisions regarding fresh fruit supply chains, specifically, three mathematical models for the optimization of decisions that support the selection of growers and the purchasing of fresh fruit, their subsequent storage and transportation, and the proposal of a mathematical model for cold storage management. The third contribution is the proposal of a Decision Support System (DSS), which aids in decisions about growers selection and purchasing of fresh fruit, as well as its subsequent storage and transportation. Finally, there is an important additional contribution that involves the application of the models to real cases. All models proposed were created and validated with the support of agro-industries from the centersouth region of the country having problems with their supply chain, which were addressed in this research study

Planning and Scheduling Optimization

Although planning and scheduling optimization have been explored in the literature for many years now, it still remains a hot topic in the current scientific research. The changing market trends, globalization, technical and technological progress, and sustainability considerations make it necessary to deal with new optimization challenges in modern manufacturing, engineering, and healthcare systems. This book provides an overview of the recent advances in different areas connected with operations research models and other applications of intelligent computing techniques used for planning and scheduling optimization. The wide range of theoretical and practical research findings reported in this book confirms that the planning and scheduling problem is a complex issue that is present in different industrial sectors and organizations and opens promising and dynamic perspectives of research and development

A Three-dimensional Matching Model for Perishable Production Scheduling

AbstractIn the production of perishable goods, particular stress is often given to performance indicators generally less critical in such manufacturing settings as metal-cutting, or mechanical/electronic assembly. For instance, in food or biochemical productions, a prominent interest of the producer is to reduce the time from distribution to the so-called best-before end. A scheduling problem with a goal of this sort is here addressed. The decision variables considered are launching and completion times of parts in a production line with critical aspects in the initial and/or final stages. The basic problem is to find an assignment of a maximum number of products to launching and completion times, so that no two products are assigned the same launching or completion time: feasible solutions have therefore the form of three-dimensional matchings. The problem is studied under two independent respects, assuming either (i) the relative perishability of products or (ii) the feasibility of launching/completion time pairs not affected by the intermediate transformation stage. We show that the problem is NP-Complete, even under such a ranking assumption as (i), whereas is in P under assumption (ii). Polynomial-time algorithms are also proposed to solve other optimization versions of the problem (in two cases, based on the identification of a matroid structure)

Integrierte Produktions- und Distributionsplanung mit Routingentscheidungen

Die zentrale Problemstellung dieser Arbeit entstammt dem operationellen Supply Chain Management. Es liegen Bestellungen von Kunden vor, für die jeweils zu entscheiden ist, ob sie angenommen werden sollen. Die angenommenen Bestellungen sind auf einem vorhandenen Maschinenpark zu produzieren und fertiggestellte Bestellungen sind an den jeweiligen Kunden auszuliefern. Zu diesem Zwecke steht eine Transporterflotte bereit, wobei die Auslieferung in der Form "Sammelauslieferung mit Rundreise" erfolgen soll. Diese allgemeine Problemstellung lässt sich anhand von 13 Eigenschaften, die unterschiedlich ausgeprägt sein können, weiter präzisieren. Es wird ein Modellierungsbaukasten entwickelt, um jede spezielle Problemstellung modellieren und mit Hilfe des MIP-Solvers CPLEX hinreichend schnell lösen zu können. Zu den weiteren Kernpunkten dieser Arbeit gehören die Entwicklung eines Branch&Bound-Verfahrens für eine spezielle Problemstellung und die Konzeption neuer, hinsichtlich ihrer Laufzeit verbesserter Modelle für das "Split Delivery Vehicle Routing Problem" sowie das "Vehicle Routing Problem With Time Windows And Multiple Use Of vehicles". This thesis addresses the field of operational supply chain management. Customers place orders which have to be accepted or declined. If an order is accepted, it has to be produced in an existing plant. Completed orders have to be shipped to the corresponding customer by an existing fleet of vehicles, using the method "batch delivery with routing". This very general problem is stated more precisely by identifying 13 properties and their possible characteristics. A tool kit is developed for modelling each of the possible problem types and solving the respective problem by the MIP solver CPLEX efficiently. Furthermore, the contribution develops a branch and bound algorithm for a specific problem type and improved models for the "Split Delivery Vehicle Routing Problem" and the "Vehicle Routing Problem With Time Windows And Multiple Use Of vehicles"