Browsing by Author "Kristin A. Thoney, Committee Co-Chair"

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Developing a Cost Model for Sourcing Products for Different Distribution Channels
(2010-04-27) Fiallos, Max; Jeffrey A. Joines, Committee Co-Chair; Kristin A. Thoney, Committee Co-Chair; Russell E. King, Committee Member
Apparel sourcing operations are extremely complex due to the intricacies of a global supply chain. Sourcing decisions should not be made without an exhaustive analysis of supply chain cost structures. Landed costs must be analyzed for sourcing decisions, but they must be complemented by information of the effects of supplier lead times and consumer-retail interactions, which are critical to overall supply chain performance. A focus on cost of goods alone gives insufficient importance to the negative effects related to forecast errors when sourcing from regions with long lead times. A supply chain cost model has been developed in this study. The model looks at cost structures for the entire supply chain from fiber to retail. The cost model shows the accrual of costs throughout each processing step within the textile and apparel industry. It also identifies costs related to international trade, including transportation costs and duties paid upon entry to the United States. The study examines the supply chain processes and costs for producing t-shirts and denim jeans in distinct regions of the world. Trade agreement duty provisions, world cotton market price competitiveness, export tax rebates, and labor rates significantly affect a countriesâ€™ competitiveness in the textile and apparel industry. The study helps identify the cost makeup of each process and the resources consumed. This model can assist companies to look outside their area of operation and have an appreciation of costs related to upstream and/or downstream processes within their supply chain. They can identify broad issues related to their strategic partnerships with suppliers and customers and investigate these in more detail. By combining supply chain costs, transportation time, and manufacturing responsiveness, analyses can be performed to identify scenarios where responsiveness is more critical than cost effectiveness. This study has found that a responsive supply chain can outweigh a lower cost but less responsive supply chain in certain sourcing environments.
On Scheduling Delivery in a Military Deployment Scenario
(2002-05-06) Melendez, Barbra Sue; Kristin A. Thoney, Committee Co-Chair; Yahya Fathi, Committee Member; Russell E. King, Committee Member; Thom J. Hodgson, Committee Co-Chair
The ability to rapidly and accurately perform sensitivity analysis in military deployment planning is a vital tool for force deployment planners. The Deployment Scheduling Analysis Tool (DSAT), a new software tool, provides this ability. DSAT builds the deployment scenario through a graphic user interface, invokes an adaptation of the Virtual Factory to schedule the movement and delivery of the equipment and provides meaningful output in the form of reports and graphics. The Virtual Factory is a job shop scheduling procedure developed at North Carolina State University which is proven to rapidly provide near-optimal solutions to large problems. This research focuses on evaluating both the accuracy and effectiveness of DSAT. An existing tool, the Deployment Analysis Network Tool Enhanced (DANTE), is proven to minimize the time required to deliver the equipment (Cmax). Since DANTE is a relaxation of the original problem, it establishes a lower bound for Cmax. An extension of DANTE, COMFLOW, includes due date information and establishes a lower bound on the maximum lateness of the equipment, Lmax. DSAT's schedule, in terms of Cmax and Lmax, are compared to their lower bounds. Finally, DSAT's schedule, in terms of transporation asset utilization, is compared to accepted asset utilization planning factors. This evaluation indicates that DSAT provides near optimal schedules for air deployments and good schedules for deployments including rail and sea movement.
Scheduling Supply Chains With Batchwise Fabric Dyeing Operations
(2004-07-30) Cho, Eunkyoung Gloria; Kristin A. Thoney, Committee Co-Chair; Russell E. King, Committee Co-Chair; Trevor J. Little, Committee Member; Thom J. Hodgson, Committee Member
Meeting customer due dates has become important for textile coloration firms' long-term survival due to rapidly changing business conditions and intense global competition. In this dissertation, optimization of the fiber-textile-apparel-retail chain, including batchwise fabric dyeing operations, was pursued. The performance of the Virtual Factory (VF), a job shop scheduling system developed at North Carolina State University, was tested in multi-factory, rolling horizon settings to more accurately predict how it would perform in industry by eliminating transient effects presented in previous experimentation. The VF performed well in all multi-factory supply chain environments. By taking the theoretical approach of color physics, setup matrices for dyeing operations were developed to include four indices; fabric/dye type, hue, lightness and chroma. After refining the matrices to capture the interdependency of the hue, lightness, and chroma of colors dyed within the same fabric/dye type, an existing sequence dependent scheduling algorithm was modified accordingly. The proposed algorithm and additional modifications were implemented in the VF, and a variety of one machine flowshop scenarios were tested against another algorithm found in the scheduling literature and a lower bound approximation. The proposed algorithm performed well in tight due date ranges and with a large number of jobs but not as well under other conditions. Sensitivity analysis of the initial parameters used in the proposed algorithm showed that its performance is highly dependent on these values.