Simulation Modeling of Dual Warehouse System

Warehouse space allocation is a critical issue to be addressed in many firms, especially firms that have various types of products. Further, most of the owned warehouse has a limited capacity which leads to the usage of outsourcing policy for warehouse storage. In this case, a rented warehouse that has more flexibility in terms of capacity is used to store the products. Therefore, an optimal decision of warehouse configuration is required. The previous study proposed a two-stage stochastic optimization model for warehouse configuration and inventory policy for deteriorating items. Unfortunately, direct implementation of their proposed method in real case problems will incur high cost and takes up a lot of time. In this research, a simulation model is developed to monitor the real condition in the company as well as to ensure that the warehouse configuration is suitable to be implemented. A textile and apparel company is used as the study case. The result shows that simulation model can be used to monitor the real condition as well as to obtain the net profit when facing different demand possibility. Keywords: inventory control; real-time monitoring; system simulation; warehouse configuration; warehouse space allocatio

The Retail City in Greater Birmingham – The changing face of urban retail districts as a result of retail-led regeneration and containment policy

The paper critically reviews retail-led regeneration and retail containment polices and their effects on the urban retail in the UK by analysing the effect that retail-led mega-schemes regeneration projects have on the economic growth of inner cities. There is significant controversy whether mega-schemes in retail-led regeneration initiatives contribute to the growth of local economies or whether it leads to the pitch shifting and marginalisation of local retail. The research focuses on two neighbouring strategies in Birmingham and Solihull to determine differences in the application of retail-led regeneration in inner city and peripheral locations. Birmingham’s Bullring centre and Solihull’s Touchstone centre was researched using quantitative data on the growth of the retail sector in Birmingham and supplemented using interviews with key actors. The paper critically analyses whether retail-led mega-schemes have a net positive effect on the economic revitalisation of the deteriorating inner cities. The results of the research indicate that the retail-led regeneration initiative brought about a dual economy with a global inner core of national retail and the outer core of marginalised local retail. The economic motive of implementing retail-led regeneration is doubted, as the research delivers mixed results. However the research indicates that the strategic benefits of restructuring and marketing the city have become equally if of not more important in retail-led regeneration initiatives than the actual economic benefits for the local economic community.

Stochastic Optimization Models for Perishable Products

For many years, researchers have focused on developing optimization models to design and manage supply chains. These models have helped companies in different industries to minimize costs, maximize performance while balancing their social and environmental impacts. There is an increasing interest in developing models which optimize supply chain decisions of perishable products. This is mainly because many of the products we use today are perishable, managing their inventory is challenging due to their short shelf life, and out-dated products become waste. Therefore, these supply chain decisions impact profitability and sustainability of companies and the quality of the environment. Perishable products wastage is inevitable when demand is not known beforehand. A number of models in the literature use simulation and probabilistic models to capture supply chain uncertainties. However, when demand distribution cannot be described using standard distributions, probabilistic models are not effective. In this case, using stochastic optimization methods is preferred over obtaining approximate inventory management policies through simulation. This dissertation proposes models to help businesses and non-prot organizations make inventory replenishment, pricing and transportation decisions that improve the performance of their system. These models focus on perishable products which either deteriorate over time or have a fixed shelf life. The demand and/or supply for these products and/or, the remaining shelf life are stochastic. Stochastic optimization models, including a two-stage stochastic mixed integer linear program, a two-stage stochastic mixed integer non linear program, and a chance constraint program are proposed to capture uncertainties. The objective is to minimize the total replenishment costs which impact prots and service rate. These models are motivated by applications in the vaccine distribution supply chain, and other supply chains used to distribute perishable products. This dissertation also focuses on developing solution algorithms to solve the proposed optimization models. The computational complexity of these models motivated the development of extensions to standard models used to solve stochastic optimization problems. These algorithms use sample average approximation (SAA) to represent uncertainty. The algorithms proposed are extensions of the stochastic Benders decomposition algorithm, the L-shaped method (LS). These extensions use Gomory mixed integer cuts, mixed-integer rounding cuts, and piecewise linear relaxation of bilinear terms. These extensions lead to the development of linear approximations of the models developed. Computational results reveal that the solution approach presented here outperforms the standard LS method. Finally, this dissertation develops case studies using real-life data from the Demographic Health Surveys in Niger and Bangladesh to build predictive models to meet requirements for various childhood immunization vaccines. The results of this study provide support tools for policymakers to design vaccine distribution networks

Modelling of Coordinating Production and Inventory Cycles in A Manufacturing Supply Chain Involving Reverse Logistics

In today’s global and competitive markets selling products at competitive prices, coordination of supply chain configuration, and environmental and ecological consciousness and responsibility become important issues for all companies around the world. The price of products is affected by costs, one of which is inventory cost. Inventory does not give any added value to products but must be kept in order to fulfill the customer demand in time. Therefore, this cost must be kept at the minimum level. In order to reduce the amount of inventory across a supply chain, coordination of decisions among all players in the chain is necessary. Coordination is needed not only for a two-level supply chain involving a manufacturer and its customers, but also for a complex supply chain of multiple tiers involving many players. With increasing attention being placed to environmental and ecological consciousness and responsibility, companies are keen to have a reverse supply chain where used products are collected and usable components remanufactured and reused in production to minimize negative impacts on the environment, adding further complexity to decision making across a supply chain. To deal with the above issues, this thesis proposes and develops the mathematical models and solution methods for coordinating the production inventory system in a complex manufacturing supply chain involving reverse logistics and multiple products. The supply chain consists of tier-2 suppliers for raw materials, tier-1 suppliers for parts, a manufacturer who manufactures and assembles parts into finished products, distributors, retailers and a third party who collects the used products and returns usable parts to the system. The models consider a limited contract period among all players, capacity constraints in transportation units and stochastic demand. The solution methods for solving the models are proposed based on decentralized, semi-centralized and centralized decision making processes. Numerical examples are used by adopting data from the literature to demonstrate, test, analyse and discuss the models. The results show that centralised decision making process is the best way to coordinate all players in the supply chain which minimise total cost of the supply chain as a whole. The results also show that the selection of the length of limited horizon/ contract period will be one of the main factors which will determine the type of coordination (decentralised, centralised or semi-centralised) among all players in the supply chain. We also found that the models developed can be viewed as generalised models for multi-level supply chain by examining the models using systems of different tiers from the literature. We conclude that the models are insensitive to changes of input parameters since percentage changes of the supply chain’s total cost are less than percentage changes of input parameters for the scenarios studied

An economic order quantity model for imperfect and deteriorating items with freshness and inventory level-dependent demand

Dissertation (MEng (Industrial Engineering))--University of Pretoria, 2023.Consumer purchasing behaviour is influenced by many factors. Depending on the circumstances, these factors may become relevant drivers of important supply chain decisions. Expiration dates have an influence on the purchasing decision of consumers for perishable goods. Another behavioural influence that stimulates demand is the volume of goods that are available on display as part of the purchase transaction. Furthermore, the fact that certain goods deteriorate over time must also be evaluated within the context of the study of perishable goods. The market is increasingly seeking goods that have no inherent defects or imperfections. This investigation seeks to determine the impact of imperfect quality, deterioration, freshness and inventory level and also, how those issues can be improved upon in workable situations. This paper proposes an inventory model that stipulates the demand as a function of freshness and the inventory level. In addition, the inventory depletes through both deterioration and demand, and the product quality is not always perfect. The objective of the inventory model is to maximise the system’s profit, hence the study has developed a theoretical mathematical model for imperfect and deteriorating items with freshness and inventory level-dependent demand. A numerical example was used to illustrate the practical application of the model in a real life environment. Sensitivity studies were conducted to determine the impact of changes or variations to the inputs that are used in the model. The findings were that the date of expiry, the elasticity of demand and the selling price of the perfect products are the main constituents that affect the profitability.Industrial and Systems EngineeringMEng (Industrial Engineering)Unrestricte

Beyond Markets and Hierarchies: Toward a New Synthesis of American Business History

We sketch a new synthesis of American business history to replace (and subsume) that put forward by Alfred D. Chandler, Jr., most famously in his book The Visible Hand (1977). We see the broader subject as the history of the institutions of coordination in the economy, with the management of information and the addressing of problems of informational asymmetries representing central problems for firm- and relationship design. Our analysis emphasizes the endogenous adoption of coordination mechanisms in the context of evolving but specific operating conditions and opportunities. This naturally gives rise both to change and to heterogeneity in the population of coordination mechanisms to be observed in use at any moment in time. In discussing the changes in the population of mechanisms over time, we seek to avoid the tendency, exemplified by Chandler's work but characteristic of the field, to see history of adoption in teleological rather than evolutionary perspective. We see a richer set of mechanisms in play than is conventional and a more complex historical process at work, in particular a process in which hierarchical institutions have both risen and, more recently, declined in significance.

Impact of RFID information-sharing coordination over a supply chain with reverse logistics

Companies have adopted environmental practices such as reverse logistics over the past few decades. However, studies show that aligning partners inside the green supply chain can be a substantial problem. This lack of coordination can increase overall supply chain cost. Information technology such as Radio Frequency Identification (RFID) has the potential to enable decentralized supply chain coordinate their information. Even though there are research that address RFID on traditional supply chain, few researches address how to coordinate RFID information sharing in a green supply chain. We study, through simulation experiments, two types of RFID information-sharing coordination under different configurations related with their inventory policies: basic and advanced. Statistical analyses show that better results can be presented in advanced RFID configuration given new coordination and inventory policy decisions presented. In addition, these findings shows what are the RFID information-sharing coordination that can provide better system improvement depending on the supply chain scenarios and factors

Peace Dividend: The War Assets Corporation and the Disposal of Canada\u27s Munitions and Supplies, 1943-1948

This dissertation is the first full-length study to explore how the Canadian government and military disposed of surplus munitions and supplies after the Second World War. By investigating how the state planned and implemented its disposal program from 1943 to 1948, this thesis places objects at the centre of attention and demonstrates their profound political, social, and economic significance. By examining the extended social lives of munitions and supplies in relationship to their postwar impact on civilian life, this study offers a new and innovative perspective that links material culture with postwar reconstruction, rehabilitation, and demobilization. What follows is a history of how Canadians turned swords into plowshares that contributes to the fields of military history, Canadian history, material culture, and disarmament studies. Disposal was an important element of Canada’s exit strategy for the Second World War because the objects accumulated to fight survived long after hostilities ended and required diligent procedures to demobilize or destroy. In November 1943, the Canadian government established the Crown Assets Allocation Committee (CAAC) and the War Assets Corporation (WAC) to plan, control, and implement its disposal program. This study elaborates on four critical themes: 1) the continuous and evolving nature of public pressure for government action on disposal; 2) the role of the CAAC and WAC in controlling disposal operations; 3) the way the objects of war require stewardship from one use to the next; and 4) the process through which munitions and supplies were reduced, reused, recycled, and upcycled into new forms, functions, and intentions. This thesis argues that through the CAAC and WAC surplus assets were disposed of to support, and not hinder, postwar reconstruction and rehabilitation. Although disposal was not perfect and left behind some dangerous environmental legacies, the conversion of surplus assets into peacetime purposes ensured that objects gained new uses and meanings thereby mitigating their threatening nature to economic stability, political authority, and public safety. Keywords: Canadian history; military history; munitions disposal; material culture; demobilization; disarmament; reconstruction; rehabilitation; peace