Decision support for build-to-order supply chain management through multiobjective optimization

This is the post-print version of the final paper published in International Journal of Production Economics. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.This paper aims to identify the gaps in decision-making support based on multiobjective optimization (MOO) for build-to-order supply chain management (BTO-SCM). To this end, it reviews the literature available on modelling build-to-order supply chains (BTO-SC) with the focus on adopting MOO techniques as a decision support tool. The literature has been classified based on the nature of the decisions in different part of the supply chain, and the key decision areas across a typical BTO-SC are discussed in detail. Available software packages suitable for supporting decision making in BTO supply chains are also identified and their related solutions are outlined. The gap between the modelling and optimization techniques developed in the literature and the decision support needed in practice are highlighted. Future research directions to better exploit the decision support capabilities of MOO are proposed. These include: reformulation of the extant optimization models with a MOO perspective, development of decision supports for interfaces not involving manufacturers, development of scenarios around service-based objectives, development of efficient solution tools, considering the interests of each supply chain party as a separate objective to account for fair treatment of their requirements, and applying the existing methodologies on real-life data sets.Brunel Research Initiative and Enterprise Fund (BRIEF

Decision support for build-to-order supply chain management through multiobjective optimization

This paper aims to identify the gaps in decision-making support based on multiobjective optimization for build-to-order supply chain management (BTOSCM). To this end, it reviews the literature available on modelling build-to-order supply chains (BTO-SC) with the focus on adopting multiobjective optimization (MOO) techniques as a decision support tool. The literature has been classified based on the nature of the decisions in different part of the supply chain, and the key decision areas across a typical BTO-SC are discussed in detail. Available software packages suitable for supporting decision making in BTO supply chains are also identified and their related solutions are outlined. The gap between the modelling and optimization techniques developed in the literature and the decision support needed in practice are highlighted and future research directions to better exploit the decision support capabilities of MOO are proposed

Mixed integer programming formulations and heuristics for joint production and transportation problems.

In this thesis we consider different joint production and transportation problems. We first study the simplest two-level problem, the uncapacitated two-level production-in-series lot-sizing problem (2L-S/LS-U). We give a new polynomial dynamic programming algorithm and a new compact extended formulation for the problem and for an extension with sales. Some computational tests are performed comparing several reformulations on a NP-Hard problem containing the 2L-S/LS-U as a relaxation. We also investigate the one-warehouse multi-retailer problem (OWMR), another NP-Hard extension of the 2L-S/LS-U. We study possible ways to tackle the problem effectively using mixed integer programming (MIP) techniques. We analyze the projection of a multi-commodity reformulation onto the space of the original variables for two special cases and characterize valid inequalities for the 2L-S/LS-U. Limited computational experiments are performed to compare several approaches. We then analyze a more general two-level production and transportation problem with multiple production sites. Relaxations for the problem for which reformulations are known are identified in order to improve the linear relaxation bounds. We show that some uncapacitated instances of the basic problem of reasonable size can often be solved to optimality. We also show that a hybrid MIP heuristic based on two different MIP formulations permits us to find solutions guaranteed to be within 10% of optimality for harder instances with limited transportation capacity and/or with additional sales. For instances with big bucket production or aggregate storage capacity constraints the gaps can be larger. In addition, we study a different type of production and transportation problem in which cllients place orders with different sizes and delivery dates and the transportation is performed by a third company. We develop a MIP formulation and an algorithm with a local search procedure that allows us to solve large instances effectively.

Supply Chain Digitalization – Optimizing The Factory Material Flow

Nykypäivän kiristynyt kilpailu ja edistyneet toimitusketjut edellyttävät entistä parempaa tomistusketjun digitalisointia parantamaan tehokkuutta, toimistusvarmuutta ja yrityksen kannattavuutta. Toimitusketjun digitalisoinnin avulla voidaan tukea reaaliaikaisesti muuttuvaa kysyntää valmistusyksikössä, luomalla älykäs toimitusketju joka tukee kysyntälähtöistä arvoketjua. Tämän tutkimuksen tarkoituksena on selvittää ja esittää kohdeyritykselle mahdolliset toiminallisuudet ja tuotteet SAP S/4HANA:sta jotka tukevat kohdeyrityksen nykyisiä ja suunniteltuja toimitusketjun prosesseja. Työssä tutkitaan hankinnasta, varastonhallintaan ja valmistukseen liittyviä toiminallisuuksia. Toiminnallisuudet analysoidaan kohdeyrityksen näkökulmasta ja verrataan vaatimuksiin, joita kohdeyrityksessa nostetaan esille. Tutkielman teoreettinen osuus pohjautuu toimitusketjun ja ERP SAP uuteen tuotteeseen SAP S/4HANA. Toimitusketjun osuudessa tuodaan esille, kuinka vaatimukset Toimitusketju 4.0 ja Teollisuus 4.0 voidaan nähdä suuntaviivoina SAP S/4HANA:n kehitykselle. Empiirinen osuus jakautuu kahteen tutkimuskysymykseen: Mitkä ovat tulevaisuuden mahdollisuudet visualisoida, arvioida ja optimoida toimitusketjua SAP S/4HANA ydintoiminnoilla? Mitä hyötyä kohde-yritys voi saavuttaa ottamalla käyttöön SAP S/4HANA laajennetut toiminallisuudet? Työn tuloksena saatiin ymmärrys SAP S/4HANA tuotteesta ja sen mahdollisuuksista toimitusketjun osalta. SAP S/4HANA tuotteena tukee monia kohdeyrityksen vaatimuksia ylätasolla, mutta vaatii konkreettisempia tutkimuksia ja testausta kohdeyrityksen työskentely ympäristössä sekä pitäisi hyödyntää kohdeyrityksen dataa.Today’s increasing competition and advanced supply chain needs better digitized supply chain to improve efficiency, on time delivery and business profitability. Supply chain digitalization enable to have real- time optimized supply chain. Supply chain management supporting the variable manufacturing unit demand by creating smart supply chain that supports the demand-driven value chain. The purpose of the study is to investigate and present how the SAP S/4HANA functionalities and products could support the case company and defined supply chain processes. The study explores supply chain from purchasing, inventory management to manufacturing. Functionalities are analysed from case company perspective and are compared to requirements what case company has raised up. Theoretical chapters focus on the supply chain and ERP SAP new product SAP S/4HANA. Supply chain chapter is divided to Supply 4.0 and Industry 4.0 to bring up the view how the SAP S/4HANA is aligned with these topics. Empirical part is divided into two research questions: What are the future capabilities to visualize, evaluate and optimize the supply chain including the core functionalities of the SAP S/4HANA? What benefits the case company can achieve by implementing the extended functionalities of the SAP S/4HANA? As a result of the study a good understanding of the SAP S/4HANA product and the possibility related to supply chain was reached. SAP S/4HANA as a product supports most of the requirements from case company in high level but requires more specific research and testing in company environment with real company data

Bütünleşik tedarik zinciri çizelgeleme modelleri: Bir literatür taraması

Research on integration of supply chain and scheduling is relatively recent, and number of studies on this topic is increasing. This study provides a comprehensive literature survey about Integrated Supply Chain Scheduling (ISCS) models to help identify deficiencies in this area. For this purpose, it is thought that this study will contribute in terms of guiding researchers working in this field. In this study, existing literature on ISCS problems are reviewed and summarized by introducing the new classification scheme. The studies were categorized by considering the features such as the number of customers (single or multiple), product lifespan (limited or unlimited), order sizes (equal or general), vehicle characteristics (limited/sufficient and homogeneous/heterogeneous), machine configurations and number of objective function (single or multi objective). In addition, properties of mathematical models applied for problems and solution approaches are also discussed.Bütünleşik Tedarik Zinciri Çizelgeleme (BTZÇ) üzerine yapılan araştırmalar nispeten yenidir ve bu konu üzerine yapılan çalışma sayısı artmaktadır. Bu çalışma, bu alandaki eksiklikleri tespit etmeye yardımcı olmak için BTZÇ modelleri hakkında kapsamlı bir literatür araştırması sunmaktadır. Bu amaçla, bu çalışmanın bu alanda çalışan araştırmacılara rehberlik etmesi açısından katkı sağlayacağı düşünülmektedir. Bu çalışmada, BTZÇ problemleri üzerine mevcut literatür gözden geçirilmiş ve yeni sınıflandırma şeması tanıtılarak çalışmalar özetlenmiştir. Çalışmalar; tek veya çoklu müşteri sayısı, sipariş büyüklüğü tipi (eşit veya genel), ürün ömrü (sınırlı veya sınırsız), araç karakteristikleri (sınırlı/yeterli ve homojen/heterojen), makine konfigürasyonları ve amaç fonksiyonu sayısı (tek veya çok amaçlı) gibi özellikler dikkate alınarak kategorize edildi. Ayrıca problemler için uygulanan matematiksel modellerin özellikleri ve çözüm yaklaşımları da tartışılmıştır

Use Of Genetic Algorithms in Supply Chain Management. Literature Review and Current Trends

For the past few decades SCM has been one of the main objectives in research and practice. Since that time researchers have developed a lot of methods and procedures which optimized this process. To create an efficient supply chain network the resources and factories must be tightly integrated. The most supply chain network designs have multiple layers, members, periods, products, and comparative resources constraints exist between different layers. Supply chain networks design is related to the problems which are very popular in literature. The subject of this paper is to present the variants, configurations and parameters of genetic algorithm (GA) for solving supply chain network design problems. We focus on references from 2000 to 2011. Furthermore, current trends are introduced and discussed

Civil tiltrotor missions and applications. Phase 2: The commercial passenger market

The commercial passenger market for the civil tiltrotor was examined in phase 2. A market responsive commercial tiltrotor was found to be technically feasible, and a significant worldwide market potential was found to exist for such an aircraft, especially for relieving congestion in urban area-to-urban area service and for providing cost effective hub airport feeder service. Potential technical obstacles of community noise, vertiport area navigation, surveillance, and control, and the pilot/aircraft interface were determined to be surmountable. Nontechnical obstacles relating to national commitment and leadership and development of ground and air infrastructure were determined to be more difficult to resolve; an innovative public/private partnership is suggested to allow coordinated development of an initial commercial tiltrotor network to relieve congestion in the crowded US Northeast corridor by the year 2000

Sustainable practices implemented in the supply chain of multinational companies

This master thesis aims to examine the strategies that multinational companies are implementing to become more sustainable in their supply chain, to create more value and be more competitive in the market. Through a qualitative approach, I conducted a comparative case study of three multinational companies that have sustainability as part of their corporate objectives. The findings suggest that even though every multinational company is applying different practices, the main strategy of all is to highly invest in new technologies and innovate their processes to reduce their carbon footprint and switch to a more circular economy. Additionally, companies are also paying attention to the source of their raw materials and how to create final products that can be recycled for future use.Esta tese de mestrado tem como objetivo examinar as estratégias que as empresas multinacionais estão a implementar para se tornarem mais sustentáveis na sua cadeia de suprimentos, para criarem mais valor e serem mais competitivas no mercado. Por meio de uma abordagem qualitativa, realizei um estudo de caso comparativo em três empresas multinacionais que têm a sustentabilidade como parte de seus objetivos corporativos. Os resultados sugerem que, embora cada empresa multinacional esteja a aplicar práticas diferentes, a principal estratégia de todas é investir fortemente em novas tecnologias e inovar os seus processos para reduzir sua pegada de carbono e mudar para uma economia mais circular. Além disso, todas as empresas também estão atentas à origem de suas matérias-primas e a como criar produtos finais que possam ser reciclados para uso futuro

Commodity Market Dynamics and the Joint Executive Committee (1880-1886)

Using weekly spot and future commodity prices in Chicago and New York, we construct expected transportation rates for grain between these two cities, expected inventory levels in New York, and realized errors in the expectations of such variables. We incorporate these exogenous com- modity market dynamics into Porter’s (1983) structural modeling of the Joint Executive Committee Railroad Cartel. As in Porter, we model mar- ginal cost as a parametric function of (instrumented) output, among other factors. Unlike Porter, we model pricing over marginal cost as a nonparamet- ric function of a set of variables, which include expectations of deterministic demand cycles and cartel stability. We estimate the pricing and demand equation simultaneously and semiparametrically. Our estimated weekly markups during periods of cartel stability are shown to reflect optimal collu- sive pricing over deterministic business cycles, as modeled in Haltiwanger and Harrington (1991). Periods of cartel instability are proven to be triggered by realized mistakes in expectations of New York grain prices