APPLICATION OF THE EXTENDED MRP THEORY TO A BABY FOOD COMPANY

Actual markets require companies to think about new ways to improve their business or to get additional advantages from their existing competences. Such improvements should not be limited to optimisation of individual activity cells but should be the result of broader analyses. Companies should consider their whole supply chains and make deep observation of dependencies between individual activity cells. Material requirements planning (MRP) Theory has proved to be a successful tool for describing and evaluating multistage, multilevel production systems with the use of Net Present Value (NPV) calculation. Recently, this theory has been extended in a way that it also deals with other vital parts of global supply chains, such as distribution, consumption and the reverse logistics. We call this approach the Extended MRP Theory (EMRP Theory). This paper shows how EMRP Theory can be used in analysing business processes for a Spanish company dedicated to baby food production

Net present value evaluation of energy production and consumption in repeated reverse logistics

The paper is based on Grubbström’s MRP theory previously used in analysis of production processes “under one roof ”. This theory has recently been extended to model global supply chains by Bogataj and Grubbström, both scientists from the MEDIFAS faculty. Every production cycle is followed by distribution, consumption and recycling activities. In broad supply chains, transportation costs between pairs of activity cells have a significant impact on the overall net present value of the system. Possible flows inside or between subsystems can all be described with input-output matrices H and G. Recently published papers of the above mentioned authors describe the presentation of supply chains in a generalized form. Generalized input and output matrices H( )s ( and ( )s ( G hold technical coefficients and lead times. Lead times are split into 2 parts: production and transportation. As presented in the publication of R. W. Grubbström, L. Bogataj and M. Bogataj, and further research of these authors, the results of recycling activities in the extended MRP model are the recovered and the waste items, but in their model the recycling of the items is not repeated. Recovered items could be reused several times in future production cycles, reducing the need to purchase new items on the market as considered here. The waste items must be disposed of, requiring environmental taxes which vary among regions, depending on local environmental policy. If recovered, items must be delivered from the recycling facility back to production, and waste items must be sent to landfills. This process requires an expenditure of human resources, and energy at each activity cell plays an important role. In this article we show how the location of recycling facilities, the prices and quantity of energy needed and the environmental taxes can drastically influence the net present value for the entire system. We also present the method for evaluating cases where energy can be recovered during recycling or decomposition processes at landfills. It is also assumed that energy recovery can be stimulated with subsidized purchase prices, but generally, lower quality energy can be expected as an output of these processes. This paper introduces generalized input and output energy matrices, which describe these energy flows and their impact on environmental sustainability through the net present value of the system, which is the novelty in the extended MRP theory. First published online: 17 Sep 201

International Logistics

In this study guide the essence, the basic conceptions and the role of international logistics in economic development, the international and organizational aspects of procurement logistics, international warehousing, conceptual foundations of distribution logistics and inernational transport logistics are examined. This study guide is intended for students of specialty “International Economic Relations”

A New Extended MILP MRP Approach to Production Planning and Its Application in the Jewelry Industry

It is important to manage reverse material flows such as recycling, reusing, and remanufacturing in a production environment. This paper addresses a production planning problem which involves reusing of scrap and recycling of waste that occur in the various stages of the production process and remanufacturing/recycling of returns in a closed-loop supply chain environment. An extended material requirement planning (MRP) is proposed as a mixed integer linear programming (MILP) model which includes-beside forward-these reverse material flows. The proposed model is developed for the jewelry industry in Turkey, which uses gold as the primary resource of production. The aim is to manage these reverse material flows as a part of production planning to utilize resources. Considering the mostly unpredictable nature of reverse material flows, the proposed model is likewise transformed into a fuzzy model to provide a better review of production plan for the decision maker. The suggested model is examined through a case study to test the applicability and efficiency

Supply Chain

Traditionally supply chain management has meant factories, assembly lines, warehouses, transportation vehicles, and time sheets. Modern supply chain management is a highly complex, multidimensional problem set with virtually endless number of variables for optimization. An Internet enabled supply chain may have just-in-time delivery, precise inventory visibility, and up-to-the-minute distribution-tracking capabilities. Technology advances have enabled supply chains to become strategic weapons that can help avoid disasters, lower costs, and make money. From internal enterprise processes to external business transactions with suppliers, transporters, channels and end-users marks the wide range of challenges researchers have to handle. The aim of this book is at revealing and illustrating this diversity in terms of scientific and theoretical fundamentals, prevailing concepts as well as current practical applications

Balancing Demand and Supply in Complex Manufacturing Operations: Tactical-Level Planning Processes

By balancing medium-term demand and supply, tactical planning enables manufacturing firms to realize strategic, long-term business objectives. However, such balancing in engineer-to-order (ETO) and configured-to-order (CTO) operations, due to the constant pressure of substantial complexity (e.g., volatility, uncertainty, and ambiguity), induces frequent swings between over- and undercapacity and thus considerable financial losses. Manufacturers respond to such complexity by using planning processes that address the business’s needs and risks at various medium-term horizons, ranging from 3 months to 3 years. Because the importance of decision-making increases exponentially as the horizon shrinks, understanding the interaction between complexity and demand-supply balancing requires extending findings reported in the literature on operations and supply chain planning and control. Therefore, this thesis addresses complexity’s impact on planning medium-term demand-supply balancing on three horizons: the strategic– tactical interface, the tactical level, and the tactical–operational interface.To explore complexity’s impact on demand–supply balancing in planning processes, the thesis draws on five studies, the first two of which addressed customer order fulfillment in ETO operations. Whereas Study I, an in-depth single-case study, examined relevant tactical-level decisions, planning activities, and their interface with the complexity affecting demand–supply balancing at the strategic–tactical interface, Study II, an in-depth multiple-case study, revealed the cross-functional mechanisms of integration affecting those decisions and activities and their impact on complexity. Next, Study III, also an in-depth multiple-case study, investigated areas of uncertainty, information-processing needs (IPNs), and information-processing mechanisms (IPMs) within sales and operations planning in ETO operations. By contrast, Studies IV and V addressed material delivery schedules (MDSs) in CTO operations; whereas Study IV, another in-depth multiple-case study, identified complexity interactions causing MDS instability at the tactical–operational interface, Study V, a case study, quantitatively explained how several factors affect MDS instability.Compiling six papers based on those five studies, the thesis contributes to theory and practice by extending knowledge about relationships between complexity and demand–supply balancing within a medium-term horizon. Its theoretical contributions, in building upon and supporting the limited knowledge on tactical planning in complex manufacturing operations, consist of a detailed tactical-level planning framework, identifying IPNs generated by uncertainty, pinpointing causal and moderating factors of MDS instability, and balancing complexity-reducing and complexity-absorbing strategies, cross-functional integrative mechanisms, IPMs, and dimensions of planning process quality. Meanwhile, its practical contributions consist of concise yet holistic descriptions of relationships between complexity in context and in demand– supply balancing. Manufacturers can readily capitalize on those descriptions to develop and implement context-appropriate tactical-level planning processes that enable efficient, informed, and effective decision-making

Application of lean scheduling and production control in non-repetitive manufacturing systems using intelligent agent decision support

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Lean Manufacturing (LM) is widely accepted as a world-class manufacturing paradigm, its currency and superiority are manifested in numerous recent success stories. Most lean tools including Just-in-Time (JIT) were designed for repetitive serial production systems. This resulted in a substantial stream of research which dismissed a priori the suitability of LM for non-repetitive non-serial job-shops. The extension of LM into non-repetitive production systems is opposed on the basis of the sheer complexity of applying JIT pull production control in non-repetitive systems fabricating a high variety of products. However, the application of LM in job-shops is not unexplored. Studies proposing the extension of leanness into non-repetitive production systems have promoted the modification of pull control mechanisms or reconfiguration of job-shops into cellular manufacturing systems. This thesis sought to address the shortcomings of the aforementioned approaches. The contribution of this thesis to knowledge in the field of production and operations management is threefold: Firstly, a Multi-Agent System (MAS) is designed to directly apply pull production control to a good approximation of a real-life job-shop. The scale and complexity of the developed MAS prove that the application of pull production control in non-repetitive manufacturing systems is challenging, perplex and laborious. Secondly, the thesis examines three pull production control mechanisms namely, Kanban, Base Stock and Constant Work-in-Process (CONWIP) which it enhances so as to prevent system deadlocks, an issue largely unaddressed in the relevant literature. Having successfully tested the transferability of pull production control to non-repetitive manufacturing, the third contribution of this thesis is that it uses experimental and empirical data to examine the impact of pull production control on job-shop performance. The thesis identifies issues resulting from the application of pull control in job-shops which have implications for industry practice and concludes by outlining further research that can be undertaken in this direction