Background Loading efficiency within logistics is a research area which has been given a lot of attention by researchers during recent years. Pallet Loading Problem has been presented as a mean to tackle the loading efficiency issue in this area. Loading efficiency can be measured in terms of fill rate of the load and the number of reclaimed gods. Different loading methods presents advantages and disadvantages regarding the two presented areas fill rate and returned gods.      Purpose The purpose with this study is to examine the different issues related to implementing an efficient pallet loading method, with the help of a comparative study of alternative loading methods. In order to accomplish this, different key factors are located and identified in which the relation between these factors is displayed. Research in this area has highlighted that a streamlining of the loading process has assisted organizations in reducing their costs. The cost reduction is an effect of the reduced transport and reclaimed gods.   Methods In this comparative study of alternative loading methods, key factors in different loading methods were identified and analyzed. The data for the three key factors were collected through archival research, unstructured interviews and observations of the different procedures. The analytic tests of the data where conducted through SPSS with the likes of descriptive statistic, non-parametric t-test, correlation and logistic regression.     Results In the result of this thesis, the differences of studied loading methods are presented based on the defined key factors. Each loading method is individually analysed and later compared to the other alternative loading method in order to decide which method is the most efficient, based on the presented key factors. The analyses in the tests presents a connection between fill rate and claims but also between claims and loading method.     Conclusions Between the two presented loading methods, free pallet loading and standing pallet loading, there’s a significant difference based on the analysed key factors. Free pallet loading is concluded to be the more efficient loading method in each of the analysed categories fill rate, claims and cost of claims. This concludes free pallet loading to be the more sustainable and economically beneficial loading method. / Bakgrund Lastningseffektivitet inom logistiken är ett område som dem senaste år fått mycket uppmärksamhet där pallastning av produkter är ett centralt område. En lastningseffektivitet kan mätas i den totala fyllnadsgraden för lastningen samt vilken skaderisk det medför. Två centrala begrepp vilka studerats för lastning är Pallet Loading Problem samt Reclaimed Gods.            Ovanstående ämnesområden presenterar fördelar samt nackdelar med olika lastningsmetoder.   Syfte Syftet med denna studie är att undersöka problematiken kring att tillämpa en effektiv pallastning med hjälp av en jämförelsestudie kring alternativa lastningsmetoder. Detta då för att identifiera och kartlägga nyckelfaktorer samt sambandet mellan dessa i en lastningsprocess. Forskning visar på att en effektivisering av lastningsprocessen har hjälpt olika företag att reducera sina kostnader, genom en minskning av transport samt minimering av skaderisk för det lastade godset.   Metod Tillvägagångssättet för denna studie var att göra en jämförelsestudie där nyckelfaktorer i olika lastningsmetoder skall analyseras. Tre olika faktorer för lastning analyserades, där underlag för analysen införskaffades ur organisationens datasamling genom arkivforskning, observationer samt ostrukturerade intervjuer. Analyserna gjordes i SPSS genom de olika dataanalystesterna, deskriptiv statistik, icke parametriskt t-test, korrelation samt logistisk regression.   Resultat Resultatet av studien visar hur lastning skiljer sig åt med avseende på de tre olika nyckelkoncepten beroende på vilken metod som ligger till grund. Respektive lastningsmetod analyseras för sig själv för att sedan jämföras, detta då för att identifiera vilken som är effektivast beroende på nyckelfaktorer. Resultatet presenterar ett samband mellan claims och fyllnadsgraden samt mellan claims och metodval.    Slutsats Slutsatsen av denna studie är att bland de två presenterade lastningsmetoderna, löst liggande samt stående pallastning finns en signifikant skillnad sett till nyckelfaktorerna vilka undersökts. Löst liggande pallastning är en effektivare modell sett till samtliga av de undersökta nyckelfaktorerna det vill säga fyllnadsgrad, claims samt kostnaden vilken uppkommer i samband med claims. Detta medför att löst liggande lastning är den mer gynnsamma lastmetoden sett till både ett hållbarhets och ekonomiskt perspektiv.

Made available in DSpace on 2014-06-11T19:26:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-02Bitstream added on 2014-06-13T19:34:52Z : No. of bitstreams: 1 kitamura_bla_me_sjrp.pdf: 1729439 bytes, checksum: 6d17806c8b0fa8114efec74fe7820cab (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo deste trabalho é estudar um caso particular dos problemas de corte e empacotamento, denominado Problema de Carregamento de Paletes do Produtor. Inicialmente, uma formulação proposta na literatura é avaliada com um pacote computacional. Posteriormente, as heurísticas lagrangiana e surrogate são estudadas e um método de atualização dos multiplicadores surrogate é adaptado para este problema. A importância em se estudar o Problema de Carregamento de Paletes do Produtor é que, devido à escala e extensão de certos sistemas logísticos, um pequeno aumento do número de produtos a serem carregados sobre cada palete pode resultar em economias substanciais. A motivação em se estudar o método de atualização surrogate proposto é que, além da adaptação do presente trabalho não ter sido realizada na literatura, uma posterior aplicação desta heurística em conjunto com um procedimento branch and bound poderá render melhores resultados que outras heurísticas. / The aim of this work is studying a particular case of cutting and packing problem, so-called the Manufacturer’s Pallet Loading Problem. Initially, a formulation proposed in the literature is evaluated with a computer package. Subsequently, the lagrangian and surrogate heuristics are studied and a method to update the surrogate multiplier is adapted for this problem. The importance of studying the manufacturer’s pallet loading problem is that, due to the scale and scope of some logistics systems, a small increase in the number of products to be loaded on each pallet can result in substantial savings. The motivation of studying the proposed method of updating the surrogate multipliers is that, besides the adaptation of this work has not been carried out in the literature, further application of heuristics within a procedure branch and bound can yield better results than other heuristics.

Orientador: Silvio Alexandre de Araujo / Banca: Reinaldo Morabito / Banca: Geraldo Nunes Silva / Resumo: O objetivo deste trabalho é estudar um caso particular dos problemas de corte e empacotamento, denominado Problema de Carregamento de Paletes do Produtor. Inicialmente, uma formulação proposta na literatura é avaliada com um pacote computacional. Posteriormente, as heurísticas lagrangiana e surrogate são estudadas e um método de atualização dos multiplicadores surrogate é adaptado para este problema. A importância em se estudar o Problema de Carregamento de Paletes do Produtor é que, devido à escala e extensão de certos sistemas logísticos, um pequeno aumento do número de produtos a serem carregados sobre cada palete pode resultar em economias substanciais. A motivação em se estudar o método de atualização surrogate proposto é que, além da adaptação do presente trabalho não ter sido realizada na literatura, uma posterior aplicação desta heurística em conjunto com um procedimento branch and bound poderá render melhores resultados que outras heurísticas. / Abstract: The aim of this work is studying a particular case of cutting and packing problem, so-called the Manufacturer's Pallet Loading Problem. Initially, a formulation proposed in the literature is evaluated with a computer package. Subsequently, the lagrangian and surrogate heuristics are studied and a method to update the surrogate multiplier is adapted for this problem. The importance of studying the manufacturer's pallet loading problem is that, due to the scale and scope of some logistics systems, a small increase in the number of products to be loaded on each pallet can result in substantial savings. The motivation of studying the proposed method of updating the surrogate multipliers is that, besides the adaptation of this work has not been carried out in the literature, further application of heuristics within a procedure branch and bound can yield better results than other heuristics. / Mestre

Made available in DSpace on 2016-06-02T19:50:17Z (GMT). No. of bitstreams: 1 TeseLKO.pdf: 834201 bytes, checksum: 994d7b70c6b1001f9dec962fafc8b72e (MD5) Previous issue date: 2004-12-13 / Universidade Federal de Sao Carlos / The purpose of this work is to develop exact methods, based on Lagrangean and Surrogate relaxation, with good performance to solve the manufacturer s pallet loading problem. This problem consists of orthogonally arranging the maximum number of rectangles of sizes (l,w) and (w,l) into a larger rectangle (L,W) without overlapping. Such methods involve a tree search procedure of branch and bound type and they use, in each node of the branch and bound tree, bounds derived from Lagrangean and/or Surrogate relaxations of a 0-1 linear programming formulation. Subgradient optimization algorithms are used to optimize such bounds. Problem reduction tests and Lagrangean and Surrogate heuristics are also applied in the subgradient optimization to obtain good feasible solution. Computational experiments were performed with instances from the literature and also real instances obtained from a carrier. The results show that the methods are able to solve these instances, on average, more quickly than other exact methods, including the software GAMS/CPLEX. / O objetivo deste trabalho é desenvolver métodos exatos, baseados em relaxação Lagrangiana e Surrogate, com bom desempenho para resolver o problema de carregamento de paletes do produtor. Tal problema consiste em arranjar ortogonalmente e sem sobreposição o máximo número de retângulos de dimensões ( , ) l w ou ( , ) w l sobre um retângulo maior ( , ) L W . Tais métodos exatos são procedimentos de busca em árvore do tipo branch and bound que, em cada nó, utilizam limitantes derivados de relaxações Lagrangiana e/ou Surrogate de uma formulação de programação linear 0 1 − . Algoritmos de otimização do subgradiente são usados para otimizar estes limitantes. São aplicados ainda testes de redução do problema e heurísticas Lagrangiana e Surrogate na otimização do subgradiente para obter boas soluções factíveis. Testes computacionais foram realizados utilizando exemplos da literatura e exemplos reais, obtidos de uma transportadora. Os resultados mostram que os métodos são capazes de resolvê-los, em média, mais rapidamente do que outros métodos exatos, incluindo o software GAMS/CPLEX.