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In this study, various material handling methods are investigated and analyzed within a case company, a dishwasher manufacturer. The aim is to optimize order planning and lot size determination while reducing material handling costs and capital tied up in inventory. With the help of the analysis, suggestions have been formulated to achieve these objectives without compromising lead times. The focus of the study are the three highest-value parts of a certain product at the company. The items are found and selected by implementing an ABC-classification for the mentioned product and selecting the top three components in the A-category. The parts are the pre-assembly of the machine, the tank and the hood. From the results of the study it is recommended to implement a lot size of four for pre-assembly, three for the tank and four for the hood, based on the Economic Order Quantity (EOQ) principle. For the pre-assembly it is suggested to use a two-bin system to plan new orders for enhanced material management efficiency. For the tank component, Material Requirements Planning (MRP) is suggested for planning new orders, utilizing the revised lot size of three for optimal inventory management. For the hood component, it is recommended to adopt the same approach as the tank to plan new orders. These recommendations offer a systematic approach to material management, aligning with the overarching goals of cost reduction and reduced tied up capital in inventory within the dishwasher manufacturing process., I denna studie undersöks och analyseras metoder för materialhantering hos ett fallföretag som tillverkardiskmaskiner. Målet med studien är att optimera orderplanering och avgörandet av partistorlekar för attsänka materialhanteringskostnader och bundet kapital i inventarier. Med hjälp av analyserna har förslagformulerats för att nå dessa mål, utan att kompromissa med ledtider. Studiens fokus ligger på de tre delarna med högst värde till en viss produkt på fallföretaget. Delarna hittasgenom en implementering av ABC-klassificering där de tre komponenterna överst i A-kategorin väljs.Delarna är förmonteringen, tanken och huven. Från studiens resultat är det rekommenderat att implementera en partistorlek på fyra enheter för delenförmontering, tre för tanken och fyra för huven, baserat på Economic Order Quantity (EOQ). Förförmonteringen föreslås det att använda ett two-bin system för att planera nya ordrar för ökad effektivitetinom materialhanteringen. För tanken rekommenderas att använda Material Requirements Planning(MRP) för att planera nya ordrar. Den uppdaterade partistorleken tillåter effektivare lagerhantering. Förhuven rekommenderas samma metod för att planera nya ordrar som för tanken. Rekommendationernatillhandahåller en mer systematisk materialhantering som går i linje med målen att sänkamaterialhanteringskostnader och bundet kapital i lager inom tillverkningsprocessen för diskmaskiner.

In this study, various material handling methods are investigated and analyzed within a case company, a dishwasher manufacturer. The aim is to optimize order planning and lot size determination while reducing material handling costs and capital tied up in inventory. With the help of the analysis, suggestions have been formulated to achieve these objectives without compromising lead times. The focus of the study are the three highest-value parts of a certain product at the company. The items are found and selected by implementing an ABC-classification for the mentioned product and selecting the top three components in the A-category. The parts are the pre-assembly of the machine, the tank and the hood. From the results of the study it is recommended to implement a lot size of four for pre-assembly, three for the tank and four for the hood, based on the Economic Order Quantity (EOQ) principle. For the pre-assembly it is suggested to use a two-bin system to plan new orders for enhanced material management efficiency. For the tank component, Material Requirements Planning (MRP) is suggested for planning new orders, utilizing the revised lot size of three for optimal inventory management. For the hood component, it is recommended to adopt the same approach as the tank to plan new orders. These recommendations offer a systematic approach to material management, aligning with the overarching goals of cost reduction and reduced tied up capital in inventory within the dishwasher manufacturing process., I denna studie undersöks och analyseras metoder för materialhantering hos ett fallföretag som tillverkardiskmaskiner. Målet med studien är att optimera orderplanering och avgörandet av partistorlekar för attsänka materialhanteringskostnader och bundet kapital i inventarier. Med hjälp av analyserna har förslagformulerats för att nå dessa mål, utan att kompromissa med ledtider. Studiens fokus ligger på de tre delarna med högst värde till en viss produkt på fallföretaget. Delarna hittasgenom en implementering av ABC-klassificering där de tre komponenterna överst i A-kategorin väljs.Delarna är förmonteringen, tanken och huven. Från studiens resultat är det rekommenderat att implementera en partistorlek på fyra enheter för delenförmontering, tre för tanken och fyra för huven, baserat på Economic Order Quantity (EOQ). Förförmonteringen föreslås det att använda ett two-bin system för att planera nya ordrar för ökad effektivitetinom materialhanteringen. För tanken rekommenderas att använda Material Requirements Planning(MRP) för att planera nya ordrar. Den uppdaterade partistorleken tillåter effektivare lagerhantering. Förhuven rekommenderas samma metod för att planera nya ordrar som för tanken. Rekommendationernatillhandahåller en mer systematisk materialhantering som går i linje med målen att sänkamaterialhanteringskostnader och bundet kapital i lager inom tillverkningsprocessen för diskmaskiner.

Aquest TFG té com a objectiu principal ampliar les funcionalitats de Odoo i DDMRP, i específicament, modificar la secció de prioritize share d'Odoo per aconseguir que l'abastiment dels buffers es pugui fer mitjançant transferències entre ells. Per resoldre aquesta problemàtica, s'ha utilitzat programació lineal entera mixta. Els resultats obtinguts són positius, ja que s'ha obtingut la funcionalitat desitjada sense afectar el temps d'execució de manera significativa. Aquesta millora és essencial per a moltes empreses, perquè els permet estalviar temps i diners en el transport de productes entre magatzems., This bachelor thesis aims to expand the functionalities of Odoo and DDMRP, specifically, to modify the prioritize share section of Odoo to enable replenishment of buffers through transfers between them. To solve this problem, mixed integer linear programming has been used. The results obtained are positive, as the desired functionality has been achieved without significantly affecting the execution time. This improvement is essential for many companies, as it allows them to save time and money in the transportation of products between warehouses.

El món de la gestió empresarial és un món que està en constant evolució, i és per aquest motiu que s'ha d'estar al dia de les novetats. En tot moment emergeixen noves metodologies disruptives que canvien la forma del joc. En aquest cas, el projecte s'enquadra en un nou model de negoci dirigit per la demanda. Aquest model de negoci canvia el paradigma convencional centrat en subministrament i costos, per un altre centrat en la demanda i flux d'informació i materials. A través d'un estudi de factors com: la llista de materials dels productes, la variabilitat de la demanda i subministrament que rep l'empresa, els temps de moviment de productes o la complexitat en les operacions internes; s'aconsegueix crear un disseny que desacobla en diferents parts tota la logística interna. Així, l'empresa és capaç d'adaptar-se contínuament a una cadena de subministrament cada vegada més complexa i volàtil. El Demand Driven Institute, institució formadora d'aquest nou model, marca uns criteris per definir si una companyia compleix els requisits per a ser totalment guiada per la demanda. Un d'aquests requisits és la capacitat de realitzar projeccions o simulacions de l'estat d'inventari en un període futur. Aleshores, a partir d'aquesta projecció és possible extreure diverses conclusions sobre les necessitats del negoci a més a més d'un pla previ d'actuació. Així doncs, aquest document detalla el procés d'implementació d'un conjunt de millores en un simulador de negoci dirigit per la demanda. La implementació és en Odoo, un ERP de codi obert utilitzat per milers d'empreses arreu del món., The world of business management is a world that is constantly evolving, and it is for this reason that you must be up to date with what is new. New disruptive methodologies are emerging at all times, changing the shape of the game. In this case, the project is part of a new business model driven by demand. This business model changes the conventional paradigm focused on supply and costs, for another focused on the demand and flow of information and materials. Through a study of factors such as: the list of materials of the products, the variability of the demand and supply received by the company, product lead times or complexity in internal operations; it is possible to create a design that decouples all the internal logistics in different parts. Thus, the company can continuously adapt to an increasingly complex and volatile supply chain. The Demand Driven Institute, the institution that created this new model, establishes criteria to define whether a company meets the requirements to be fully demand-driven. One of these requirements is the ability to make projections or simulations of the inventory status in a future period. Then, from this projection it is possible to draw various conclusions about the needs of the business, in addition to a previous plan of action. Thus, this document details the implementation process of a set of improvements in a demand-driven business simulator. The implementation is in Odoo, an open source ERP used by thousands of companies around the world.

Purpose: Demand Driven Material Requirements Planning (DDMRP) aims to deal with variability byadjusting inventory levels while maintaining, or even increasing, customer service levels. This approachbridges the push and pull approaches. Even though it first made its appearance in 2011, research in thisfield remains relatively limited. This paper aims to analyze the temporal evolution of the DDMRP, itscontext of implementation, and the research themes studied in that field to identify areas that still need tobe addressed by future researchers.Design/methodology/approach: The systematic literature review approach used in this paper examinesresearch dealing with the DDMRP published in different languages between 2011 and 2020. To date,published papers focused on performance analysis and comparison of the DDMRP with other methods.This study focuses on the DDMRP itself and its capacity to answer the different operations managementfunctions under a broader vision (context, implementation, setting, etc.). Thus, we analyze the evolution ofthe method in the literature, considering different languages, and present a taxonomy of publishedscientific works. Then, we identify gaps that require further research.Findings: DDMRP is not sufficiently studied in the literature and the proposed tools still need to betested. More research is required to evaluate its adaptability in different and complex environments, addressits ability to cope with product variety, complex BOMs, and other methods. A proposal of new approachesto define and adjust DDMRP parameters and evaluate their sensitivity is also required to make the methodmore scientifically sound. Originality/value: Based on the analysis of papers published in different languages, this paper outlinesthe current state of the art of DDMRP, its shortcomings, and identifies further research to make DDMRPmore robust from both a scientific and industrial perspective, Peer Reviewed

A Master of Science thesis in Engineering Systems Management by Hessa Almatroushi entitled, "Integrated Material Lot Sizing and Multi-Resource Leveling Models with Activity Splitting," submitted in January 2015. Thesis advisor is Dr. Moncer Hariga and thesis co-advisor is Dr. Rami As'ad. Available are both soft and hard copies of the thesis., In the project management literature, project scheduling and material procurement problems are often studied separately and are addressed following a sequential approach. The few papers in the literature that integrated both problems assumed that materials are ordered and received prior to their needed activities. This research will contribute to the project management literature by developing mathematical models that integrate project scheduling and material lot sizing decisions when dealing with renewable and consumable resources having constant and variable consumption rates. The formulated models minimize renewable resource leveling related costs and material ordering and inventory associated costs for consumable resources. The models allow activity splitting to smooth the utilization of renewable resources and to optimally schedule the ordering of consumable resources. Both models with time independent and dependent rates of consumption are formulated as mixed integer linear programs. Sensitivity analysis is performed to assess the effect of varying the problem's parameters on the total project cost savings realized after the integration of leveling and ordering decisions. The results show that under certain values of the problem parameters, the integrated decision approach achieved significant cost savings compared to the sequential decision approach. While low holding costs resulted in low cost savings, high holding costs significantly boosted cost savings. Furthermore, the numerical results show that the time-variation of the resource utilization rates has an effect on cost savings. The results of the sensitivity analysis also show that reductions in both resource leveling and material ordering related costs are realized when non-critical activities are allowed to split. Among all input parameters analyzed, the ordering and holding costs had the greatest effect on the total project costs. However, for large values of the ordering and holding costs, cost savi, College of Engineering, Department of Industrial Engineering

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-14078-0_7, [EN] In this paper, a mixed-integer mathematical programming model is proposed to address a production and routing problem related to inbound logistics processes in supply chains environments. This model is also enriched with sustainable issues related to routing decisions by introducing additional fuel consumption and pollutants emissions calculations into the objective function. For the solution methodology, a two-phase decoupled solution procedure based on exact algorithms for the production model and a tabu search algorithm for the routing model is adopted. Results of computational experiments performed with a realworld automotive supply chain confirm the efficiency of the proposed solution method in terms of total cost, fuel consumptions and CPU time.

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-14078-0_7, [EN] In this paper, a mixed-integer mathematical programming model is proposed to address a production and routing problem related to inbound logistics processes in supply chains environments. This model is also enriched with sustainable issues related to routing decisions by introducing additional fuel consumption and pollutants emissions calculations into the objective function. For the solution methodology, a two-phase decoupled solution procedure based on exact algorithms for the production model and a tabu search algorithm for the routing model is adopted. Results of computational experiments performed with a realworld automotive supply chain confirm the efficiency of the proposed solution method in terms of total cost, fuel consumptions and CPU time.

"This is an Accepted Manuscript of an article published in International Journal of Production Research on December 2014, available online: http://www.tandfonline.com/10.1080/00207543.2014.920115.", In this paper, we formulate the material requirements planning) problem of a first-tier supplier in an automobile supply chain through a fuzzy multi-objective decision model, which considers three conflictive objectives to optimise: minimisation of normal, overtime and subcontracted production costs of finished goods plus the inventory costs of finished goods, raw materials and components; minimisation of idle time; minimisation of backorder quantities. Lack of knowledge or epistemic uncertainty is considered in the demand, available and required capacity data. Integrity conditions for the main decision variables of the problem are also considered. For the solution methodology, we use a fuzzy goal programming approach where the importance of the relations among the goals is considered fuzzy instead of using a crisp definition of goal weights. For illustration purposes, an example based on modifications of real-world industrial problems is used.

This paper presents a technique that mathematically models relationships between operations and materials, which amends the usual technique used to model materials and resources requirement planning through mathematical programming. This technique represents operations and materials requirement planning by extending the bill of materials concept beyond the Gozinto structure. This so-called generic materials and operations planning (GMOP) problem is based on the 'stroke' concept. The decision variables are the operations (strokes) each resource is capable of, and not materials or resources. This form extends modelling capacity to transformation operations, resource and product substitution, and material transportation. It considers most conventional bills of materials types (direct, alternative and reverse BOMs, alternative resources and routings) with the same data structure. It contemplates multi-level problem modelling, and even packaging and alternative transport modes. The same data structure represents these characteristics. The problem, its mathematical modelling approach and examples illustrating its use are provided.

This paper presents a technique that mathematically models relationships between operations and materials, which amends the usual technique used to model materials and resources requirement planning through mathematical programming. This technique represents operations and materials requirement planning by extending the bill of materials concept beyond the Gozinto structure. This so-called generic materials and operations planning (GMOP) problem is based on the 'stroke' concept. The decision variables are the operations (strokes) each resource is capable of, and not materials or resources. This form extends modelling capacity to transformation operations, resource and product substitution, and material transportation. It considers most conventional bills of materials types (direct, alternative and reverse BOMs, alternative resources and routings) with the same data structure. It contemplates multi-level problem modelling, and even packaging and alternative transport modes. The same data structure represents these characteristics. The problem, its mathematical modelling approach and examples illustrating its use are provided.

Bakalářská práce je zaměřena na problematiku operativního plánování výroby v průmyslovém podniku. Tato práce obecně charakterizuje plánování výroby v podniku. Dále podrobně popisuje konkrétní metody a systémy pro plánování výroby a zabývá se softwarem pro plánování výroby. Praktická část bakalářské práce se zabývá plánováním výroby v konkrétním podniku., The bachelor´s thesis is focused on a operative production planning in an industrial company. This paperwork generally describes production planning in a company. It describes particular methods and systems for a production planning and deals with software for production planning. The practical part of the bachelor´s thesis deals with the production planning in a particular company., Katedra ekonomiky a managementu chemického a potravinářského průmyslu, Je některý z prezentovaných pokročilých systémů plánování výroby implementované ve zkoumaném podniku? Jaké je portfolio vyráběných produktů ve zkoumaném podniku? Jakým způsobem probíhá plánování výroby ve sledovaném podniku? Studentka otázky zodpověděla.

Information system integration, which integrates information systems of trading partners throughout the supply chain, is an important aspect of supply chain integration and optimization. For example, information system integration has been shown to mitigate the bullwhip effect in supply chains. Enterprises face important challenges integrating information systems (e.g. safety issues, rapidly evolving technologies and business environments). Using (business and enterprise) ontologies as a foundation for information system integration might help overcome these challenges. In order to evaluate this approach, this paper presents an elementary material requirements planning (MRP) tool that is founded in the REA ontology as a proof of concept for building ontology-based applications that support information system integration. The purpose of this paper is to report our findings applying the ontological foundation approach while building an MRP application as part of an integrated information system.

The multilevel lot-sizing (MLLS) problem is a key production planning problem in the material requirement planning (MRP) system. The MLLS problem deals with determining the production lot sizes of various items appearing in the product structure over a given finite planning horizon to minimize the production cost, inventory carrying cost, backordering cost, etc. In a previous study, a particle swarm optimization (PSO) algorithm integrated with flexible inertial weight (WPSO-MLLS) was proposed for uncapacitated MLLS problems by embedding the characteristics of the MLLS problem, a coding system and redefinitions of operators for 'velocity' plus 'velocity', 'position' plus 'velocity', and 'position' subtract 'position'. This research further investigates the suitability of WPSO-MLLS by comparing the solving performance of WPSO-MLLS with a PSO algorithm without inertial weight (PSO-MLLS) and two extended hybrid versions of PSO, which are WPSO-MLLS integrated with crossover and mutation operators of a genetic algorithm (GA) (HWPSO-MLLS) and PSO-MLLS integrated with crossover and mutation operators of GA (HPSO-MLLS). Some benchmarking testing instances are adopted to compare these PSO algorithms.

The multilevel lot-sizing (MLLS) problem is a key production planning problem in the material requirement planning (MRP) system. The MLLS problem deals with determining the production lot sizes of various items appearing in the product structure over a given finite planning horizon to minimize the production cost, inventory carrying cost, backordering cost, etc. In a previous study, a particle swarm optimization (PSO) algorithm integrated with flexible inertial weight (WPSO-MLLS) was proposed for uncapacitated MLLS problems by embedding the characteristics of the MLLS problem, a coding system and redefinitions of operators for 'velocity' plus 'velocity', 'position' plus 'velocity', and 'position' subtract 'position'. This research further investigates the suitability of WPSO-MLLS by comparing the solving performance of WPSO-MLLS with a PSO algorithm without inertial weight (PSO-MLLS) and two extended hybrid versions of PSO, which are WPSO-MLLS integrated with crossover and mutation operators of a genetic algorithm (GA) (HWPSO-MLLS) and PSO-MLLS integrated with crossover and mutation operators of GA (HPSO-MLLS). Some benchmarking testing instances are adopted to compare these PSO algorithms.

Material Requirements Theory (MRP Theory) combines the use of Input-Output Analysis and Laplace transforms, enabling the development of a theoretical background for multi-level, multi-stage production-inventory systems together with their economic evaluation, in particular applying the Net Present Value (NPV) principle. The time scale may be continuous ("bucketless" in MRP terminology) or discrete. Since the average cost measure may be viewed as an approximation of NPV, the theory may be applied to cases, when average costs are preferred as the objective function.

In this thesis, capacity-constrained aspects of multi-level, multi-stage productionplanning are investigated. The aim has been to extend Material Requirements Planning Theory (MRP Theory) to cover more general problems dealing with capacity constraints, in particular when non-zero lead times are present and the processes take place in continuous time. MRP Theory deals with multi-level production systems with multiple items taking place either within a discrete or continuous time framework. External demand is considered either deterministic or stochastic. Lead times are assumed to be given constants, and the Net Present Value Principle has been applied as the objective function. The Bill-of-Materials, capturing component as well as capacity requirements, in volume as well as in advanced timing due to lead times, has been described using a generalised input matrix involving Laplace transforms or z transforms. In order to be able to apply Dynamic Programming as a solution method, the system state has been defined and designed in terms of a matrix, in which historical values of cumulative production and cumulative demand are given state variables. A high power computer has been used to calculate solutions to numerical examples. Moreover, this thesis examines the fundamental equations of MRP Theory in order to analyse the possibility to obtain closed-form expressions for the time development of the system, when standard ordering rules of MRP are applied. In addition, capacity-constrained production planning problems and procedures in a paper mill have been surveyed and are presented in the form of a case study.

In this thesis, capacity-constrained aspects of multi-level, multi-stage productionplanning are investigated. The aim has been to extend Material Requirements Planning Theory (MRP Theory) to cover more general problems dealing with capacity constraints, in particular when non-zero lead times are present and the processes take place in continuous time. MRP Theory deals with multi-level production systems with multiple items taking place either within a discrete or continuous time framework. External demand is considered either deterministic or stochastic. Lead times are assumed to be given constants, and the Net Present Value Principle has been applied as the objective function. The Bill-of-Materials, capturing component as well as capacity requirements, in volume as well as in advanced timing due to lead times, has been described using a generalised input matrix involving Laplace transforms or z transforms. In order to be able to apply Dynamic Programming as a solution method, the system state has been defined and designed in terms of a matrix, in which historical values of cumulative production and cumulative demand are given state variables. A high power computer has been used to calculate solutions to numerical examples. Moreover, this thesis examines the fundamental equations of MRP Theory in order to analyse the possibility to obtain closed-form expressions for the time development of the system, when standard ordering rules of MRP are applied. In addition, capacity-constrained production planning problems and procedures in a paper mill have been surveyed and are presented in the form of a case study.

A number of different standard ordering policies are presented within the methodology of Material Requirements Planning (MRP), such as Lot-For-Lot (L4L), Fixed Order Quantity (FOQ), Fixed Period Requirements (FPR), etc. In MRP theory the time development of the production-inventory system is determined by a set of fundamental equations for available inventory, total inventory and backlogs using Input-Output Analysis for capturing the Bill of Materials and Laplace transforms for describing the advanced timing requirements. This paper aims at formally introducing standard ordering policies into the fundamental equations of MRP Theory in order to analyse the possibility to obtain closed-form expressions for the time development of the system, when such rules are applied.

In this thesis, capacity-constrained aspects of multi-level, multi-stage productionplanning are investigated. The aim has been to extend Material Requirements Planning Theory (MRP Theory) to cover more general problems dealing with capacity constraints, in particular when non-zero lead times are present and the processes take place in continuous time. MRP Theory deals with multi-level production systems with multiple items taking place either within a discrete or continuous time framework. External demand is considered either deterministic or stochastic. Lead times are assumed to be given constants, and the Net Present Value Principle has been applied as the objective function. The Bill-of-Materials, capturing component as well as capacity requirements, in volume as well as in advanced timing due to lead times, has been described using a generalised input matrix involving Laplace transforms or z transforms. In order to be able to apply Dynamic Programming as a solution method, the system state has been defined and designed in terms of a matrix, in which historical values of cumulative production and cumulative demand are given state variables. A high power computer has been used to calculate solutions to numerical examples. Moreover, this thesis examines the fundamental equations of MRP Theory in order to analyse the possibility to obtain closed-form expressions for the time development of the system, when standard ordering rules of MRP are applied. In addition, capacity-constrained production planning problems and procedures in a paper mill have been surveyed and are presented in the form of a case study.

In this thesis, capacity-constrained aspects of multi-level, multi-stage productionplanning are investigated. The aim has been to extend Material Requirements Planning Theory (MRP Theory) to cover more general problems dealing with capacity constraints, in particular when non-zero lead times are present and the processes take place in continuous time. MRP Theory deals with multi-level production systems with multiple items taking place either within a discrete or continuous time framework. External demand is considered either deterministic or stochastic. Lead times are assumed to be given constants, and the Net Present Value Principle has been applied as the objective function. The Bill-of-Materials, capturing component as well as capacity requirements, in volume as well as in advanced timing due to lead times, has been described using a generalised input matrix involving Laplace transforms or z transforms. In order to be able to apply Dynamic Programming as a solution method, the system state has been defined and designed in terms of a matrix, in which historical values of cumulative production and cumulative demand are given state variables. A high power computer has been used to calculate solutions to numerical examples. Moreover, this thesis examines the fundamental equations of MRP Theory in order to analyse the possibility to obtain closed-form expressions for the time development of the system, when standard ordering rules of MRP are applied. In addition, capacity-constrained production planning problems and procedures in a paper mill have been surveyed and are presented in the form of a case study.

A great deal of research has been done on capacity-constrained production–inventory systems, most of which concerns deterministic demand situations and single-product systems. In this paper we present a model of a multi-level capacity-constrained system when external demand is stochastic. Unlike the traditional total cost objective, adopted in the vast majority of capacity-constrained production–inventory models, the (expected) Net Present Value is here used as the objective function. Dynamic programming is chosen as the solution procedure. Numerical examples are given to explain the model and to illustrate features when changing available capacity. The Laplace transform together with input–output analysis are employed as tools to construct the model. This approach has been used in previous research to formulate a theoretical base for Material Requirements Planning (MRP) systems. The paper provides a further argument for the use of transforms in combination with matrix representations of product structures and capacity requirements, and it extends previous theory in the direction of capacity considerations combined with uncertainty in external demand. Dynamic programming is also shown to be a practical method for the multi-stage optimisation involved. The numerical examples further illustrate, for instance, the natural propensity for subordinate items to be lot sized in a more lumpy way than their parents, and also how the marginal benefit of capacity increments follows the law of diminishing returns. Also comparisons are made with solutions from the deterministic equivalence model, using average demand as a proxy.

In this paper, we study the detailed coordination problem in a two-level assembly system with stochastic lead times for lower-level items and constant and deterministic demand for the finished item. General formulae are developed for solving the optimal planned lead times with the objective to minimise total stockout and inventory holding costs. Consequently, we obtain the optimal safety lead time, which is the difference between planned and expected lead time. A solution procedure for the optimal planned lead times is discussed. Numerical examples are then given to illustrate the model. Moreover, the influence of the mean value and variance of actual lead times on the system performance and optimal control variables (such as the total cost of the system and planned lead times) is studied using our numerical results. © 2002 Elsevier Science B.V. All rights reserved.

Summary: The Material Requirement Planning System (MRP) is a key module in the Enterprise Resources Planning (ERP) systems. Finding better ways of developing systems leads to a robust MRP system and provides prototypes which can be expanded to other modules of the ERP systems. This thesis will provide an object-oriented model of a MRP system which was created and presented by using the Object Modeling Technique (OMT). The model consisted of three parts, the object model, dynamic model, and functional model. An innovative way to handle the static bill of materials (BOM) data with a more flexible dynamic item class was developed. To demonstrate the flexibility, extendability, and reusability of the object-oriented MRP model, two major business change scenarios were applied to the model. Minor changes to the design were required to accommodate major changes on the functionality of the MRP system., College of Engineering and Computer Science, Collection: FAU Electronic Theses and Dissertations Collection, Thesis (M.S.)--Florida Atlantic University, 1999.

The United States Navy is currently implementing a plan to consolidate the wholesale supply functions of the Naval Air Station at Alameda and the Naval Supply Center at Oakland. Improving supply support of the Naval Air Rework Facility Alameda in general and stock availability in particular is a vital part of the plan. Demand forecasting by workload driven material requirements planning (MRP) is being considered as a means to improve stock availability. This thesis begins with an overview of the MRP technique and the current supply support of NARF Alameda. It proceeds with the description and evaluation of a temporary MRP system that is currently implemented and uses it as a background for development of an MRP system that is designed to operate in a maintenance oriented environment in general and at NARF Alameda in particular. Finally, suggestions are made for transition from the temporary to the proposed system. (Author)

Effective manpower planning becomes complex and critical in high technology environments. In such environments, operators and maintenance personnel must be highly trained and skilled to assure that equipment will be effectively used, and changes can be rapidly implemented. The manpower planning problem becomes one of determining requirements for skilled employees early enough to ascertain training needs, to select candidates for training, to educate and train technicians before a shortage of manpower occurs, and to achieve this without excessive manpower costs. This investigation examined a new approach to the manpower planning problems--material requirements planning (MRP), which has been successfully applied in other kinds of planning problems. The general hypothesis tested was the MRP will be a more effective procedure than traditional extrapolation techniques. The test of the hypothesis involved comparing a manpower planning model using MRP concepts with one using traditional extrapolation concepts through a model of a simulated Air Force weapon system.

Inventory management techniques have gained in importance in the past few years because of the cash crunch being faced by most companies. Material Requirements Planning (MRP) is gaining rapidly in popularity, specially after the APICS (American Production and Inventory Control Society) MRP Crusade. The technique is being presented as if it were the cure for all ills. The purpose of this report is to identify a number of issues that are relevant to MRP and, wherever possible, to propose an approach. Another purpose is to study how firms tackle these issues and to present real-life implementation characteristics. With this in mind, seven firms were interviewed personally. The study concludes that the issues are largely unresolved in industry and whatever benefits are accruing are mostly due only to better timing information generated by the explosion process rather than any other formal procedures. It follows that further benefits are achievable if the issues are tackled in a scientific manner.