存貨除了可為企業帶來縮短交期的好處之外，也能夠提高企業競爭力並及時的滿足顧客需求。但過多的存貨卻造成倉儲空間的浪費、存貨成本的增加及造成企業營運資金的積壓。因此，許多管理研究都致力於建立適量、適時及成本最小化為目標的存貨模型。

      本研究即針對包含零件、半成品及成品的存貨模式進行研究，建構同時考慮以上三種存貨不同的存貨成本，並在不同時間狀態下彼此增減的存貨模型。並利用過去的歷史資料來預測未來需求，再利用窮舉法，求出最適之存貨水準。最後將本研究所求得之最適存貨水準代入實際數據，並與原固定存貨水準下所產生之成本做比較，透過數值分析確認本研究方法是否能有效降低總成本及提高效益。

      Having the necessary inventory at right time and right amount for business is helpful in shorting the delivery and improving customer service and the competitive abilities of a firm. But too much inventory leads to huge increase of costs and the waste of warehouse space. Therefore, many inventory management related studies have developed inventory models and decide when and how much to order or to manufacture so that the total costs are minimized.

      In this thesis, an inventory model is proposed that unifies the inventory problems of raw materials, sub-assemblies and finished products. The objective is to minimize the total inventory costs. This thesis uses the historical data to forecast the future order and then uses an exhaustive search method to find the optimum inventory level. Finally, it provides a numerical example to compare the inventory policy currently adopted in a real-world application and the proposed inventory policy in order to verify whether the proposed inventory policy can be used in practice.

Baldwin, C. Y. and Clark, K. B., Managing in the age of modularity, Harvard Business Review, 75(5), 84-93, 1997.

Baldwin, C. Y. and Clark, K. B., Design rules: The power of modularity, Cambridge, MA: MIT Press, 2000.

Ben-Daya, M. and Raouf A., Inventory models involving lead time as a decision variable, The Journal of the Operation Research Society, 45(5), 579-82, 1994.

Billington, P. J., The classic economic production quantity model with setup cost as function of capital expenditure, Decision Sciences, 18(1), 25-40, 1987.

Bose, S., Goswami, A. and Chaudhuri, K. S., An EOQ model for deteriorating items with linear time-dependent demand rate and shortages under inflation and time discounting, The Journal of the Operational Research Society, 46(6), 771-782, 1995.

Cárdenas-Barrón, L. E., The derivation of EOQ/EPQ inventory models with two backorders costs using analytic geometry and algebra, Applied Mathematical Modelling, 35(5), 2394-2407, 2011.

Chakrabarti, T., Giri, B. C. and Chaudhuri, K. S., An EOQ Model for Items with Weibull Distribution Deterioration, Shortages and Trended Demand: an Extension of Philips Model, Computers and Operations Research, 25(7), 649-657, 1998.

Chan, W. M., Ibrahim, R. N. and Lochert, P. B., A new EPQ model: integrating lower pricing rework and reject situations, Production Planning and Control, 14(7), 588-595, 2003.

Chang, K. J. and Tsai, S. F., On the inventory model with variable lead time and price-quantity discount, Computers & Operations Research, 28(9), 915-934, 2001.

Chang, H. C., Ouyang, L. Y., Wu, K. S., and Ho, C. H., Integrated vendor-buyer cooperative inventory models with controllable lead time and ordering cost reduction, European Journal of Operational Research, 170(2), 481-495, 2006.

Chang, H. C., and Ho, C. H., A note on solving the EOQ model with imperfect quality subject to in-house inspection, IMA Journal of Management Mathematics, 1-6, 2010.

Chen, S. H. and Wang, C. C., Backorder fuzzy inventory model under function principle, Information Sciences, 95(1-2), 71-79, 1996.

Chen, J. M., An inventory model for deteriorating items with time-proportional demand and shortages under inflation and time discounting, International Journal of Production Economics, 55(1), 21-30, 1998.

Chen, C. and Wang, L., Product platform design through clustering analysis and information theoretical approach, International Journal of Production Research
, 46(15), 4259-4284, 2008.

Cunha, C., Agard, B. and Kusiak, A., Design for cost: module-based mass customization, IEEE Transaction on Automation Science and Engineering, 4(3), 350-359, 2007.

Chung, K. J. and Hou, K. L., An Optimal Production Run Time with Imperfect Production Processes and Allowable Shortages, Computers & Operations Research, 30(4), 483-490, 2003.

Dahmus, J. B., Gonzalez-Zugasti, J. P. and Otto, K. N., Modular product architecture, ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference, September 10-13, 2000 – Baltimore, Maryland.

Erlenkotter, D., An early classic misplaced: Ford W. Harris’s economic order quantity model of 1915, Management Science, 35(7), 898-900, 1989.

Eroglu, A. and Ozdemir, G., An economic order quantity model with defective items and shortages, International Journal of Production Economics, 106(2), 544-549, 2007.

Taft, E.W., The most economical production lot, The Iron Age, 101, 1410-1412, 1918.

Ghosh, A. K., On some inventory models involving shortages under an announced price increase, International Journal of Systems Science, 34(2), 129-137, 2003.

Gonzalez-Zugasti, J. P. & Otto, K. N., Modular platform-based product family design, Proceedings of DETC’00 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference Baltimore, 10-13 September, Maryland, 2000.

Goyal, S. K., Morin, D. and Nebebe,F., The finite horizon trended inventory replenishment problem with shortages, Journal of the Operational Research Society, 43(12), 1173-1178, 1992.

Goyal, S. K., An Integrated Inventory Model for a Single Product System, Operation Research Quarterly, 28(3), 539-545, 1977.

Goyal, S. K. and Cárdenas-Barrón, L. E., Note on: economic production quantity model for items with imperfect quality – a practical approach, International Journal of Production Economics, 77(1), 85-87, 2002.

Hata, T., Kato S. and Kimura, F., Design of Product Modularity for Life Cycle Management, Department of Precision Engineering, University of Tokyo, Hongo, 7-3-1, 2001.

Hsu, W. K. and Yu, H. F., EOQ model for imperfective items under a one-time-only discount, Omega, 37(5), 1018-1026, 2009.

Hsu, W. K. and Yu, H. F., An EOQ model with imperfective quality items under an announced price increase, Journal of the Chinese Institute of Industrial Engineers, 28(1), 34-44, 2011.

Huang, C. C. and Kusiak, A., Modularity in design of products and systems, IEEE Transactions on Systems, Man, and Cybernetics-Part-A: Systems and Humans, 28(1), 66-77, 1998.

Jiao, J., Simpson, T. W. and Siddique, Z., Product family design and platform-based product development: a state-of-the-art review, Journal of Intelligent Manufacturing, 18(1), 5-29, 2007.

Jose, A. and Tollenaere, M., Modular and platform methods for product family design: literature analysis, Journal of Intelligent Manufacturing, 16(3), 371-390, 2005.

Khan, M., Jaber, M. Y. and Wahab, M. I. M., Economic order quantity model for items with imperfect quality with learning in inspection, International Journal of Production Economics, 124(1), 87-96, 2010.

Khouja, M. and Park, S., Optimal lot sizing under continuous price decrease, Omega, 31(6), 539-545, 2003.

Lau, K. W., Yam, C. M., Tang, P. Y. and Sun, H. Y., Factors influencing the relationship between product modularity and supply chain integration, International Journal of Operations & Production Management, 30(9), 951-977, 2010.

Lee, W. C., Wu, J. W., and Lei, C. L., Computational algorithmic procedure for optimal inventory policy involving ordering cost reduction and back - order discounts when lead time demand is controllable, Applied Mathematics and Computation, 189(1), 186-200, 2007.

Liao, C. J. and Shyu, C. H., Analytical determination of lead time with normal demand, International Journal of Operations and Production Management, 11(9), 72-78, 1991.

Meyer, M. H. and Utterback, J. M., The product family and the dynamics of core capability, Sloan Management Review, 34(3), 29-47, 1993.

Meyer, M. H. and Lehnerd, A. P., The power of product platforms, building value and cost leadership, New York, Free Press, 1997.

Mikkola, J. H., Product architecture design: implications for modularization and interface management, Paperwork presented at LINK Workshop, 15 May, Organizing processes of Learning, Copenhagen Business School, Denmark, 2001.

Moon, I. and Choi, S., A note on lead time and distributional assumptions in continuous review inventory models, Computers & Operations Research , 25(11), 1007-1012, 1998.

Muffato, M., Introducing a platform strategy in product development, International Journal of Product Economics, 60-61, 145-153, 1999.

O’Grady, P. and Liang, W. Y., An Object Oriented Approach to Design with Modules, Computer Integrated Manufacturing System, 11(4), 267-283, 1998.

Otto, K., Identifying product family architecture modularity using function and variety heuristics, PaperWork Center for Innovation on Product Development, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA, 2001.

Ouyang, L. Y., Yeh, N. C., and Wu, K. S., Mixture inventory model with backorders and lost sales for variable lead time, Journal of the Operational Research Society, 47(6), 829-832, 1996.

Ouyang, L. Y., and Chang, H. C., Impact of investing in quality improvement on (Q,r,L) model involving the imperfect production process, Production Planning & Control: The Management of Operations, 11(6), 598-607, 2000.

Ouyang, L. Y., and Chang, H. C., Lot size reorder point inventory model with controllable lead time and set -up cost, International Journal of Systems Science,
33(8), 635-642, 2002.

Ouyang, L. Y., Chen, C. K., and Chang, H. C., Quality improvement, setup cost and lead-time reductions in lot size reorder point models with an imperfect production process, Computers & Operations Research, 29(12), 1701-1717, 2002.

Ouyang, L. Y., Wu, K. S. and Ho, C. H., Integrated vendor-buyer cooperative model with stochastic demand in controllable lead time, International Journal of Production Economics, 92(3), 255-266, 2004.

Pan, J. C. H., Hsiao, Y. C., and Lee, C. J., Inventory models with fixed and variable lead time crash costs considerations, Journal of the Operational Research Society, 53(9), 1048-1053, 2002.

Pan, J. C. H. and Yang, J. S., A study of an integrated inventory with controllable lead time, International Journal of Production Research, 40(5), 1263-1273, 2002.

Pan, J. C. H. and Hsiao, Y. C., Integrated inventory models with controllable lead time and backorder discount considerations, International Journal of Production Economics, 93-94, 387-397, 2005

Salameh, M. K. and Jaber, M. Y., Economic production quantity model for items with imperfect quality, International Journal of Production Economics, 64(1-3), 59-64, 2000.

Salvador, F., Toward a product system modularity construct: literature review and reconceptualization, IEEE Transactions on Engineering Management, 54(2), 219-40, 2007.

Sana, S. S., Goyal , S. K. and Chauduri K., An imperfect production process in a volume flexible inventory model, International Journal of Production Economics, 105(2), 548-559, 2007.

Sana, S. S., Goyal , S. K. and Chauduri, K., On a volume flexible inventory model for items with an imperfect production system, International Journal of Operational Research, 2(1), 64-80, 2007.

Sarker, B. R. and Pan, H., Effects of inflation and the time value of money on order quantity and allowable shortage, International Journal of Production Economics, 34(1), 65-72, 1994.

Sarker, B. R., and Coates, E. R., Manufacturing setup cost reduction under variable
lead times and finite opportunities for investment, International Journal of Production Economics, 49(3), 237-247, 1997.

Sarker, B. R., Jammal, A. M. M., and Wang, S., Supply chain models for perishable products under inflateion and permissible delay in payment, Computers & Operations Research, 27(1), 59-75, 2000.

Sarker, B. R. and Al Kindi, M., Optimal ordering policy in response to a discount offer, International Journal of Production Economics, 100(2), 195-211, 2006.

Sawhney, M. S., Leveraged high-variety strategies: From portfolio thinking to platform thinking, Journal of the Academy of Marketing Science, 26(1), 54-61, 1998.
Schilling, M. A., Toward a general modular systems theory and its application to interfirm product modularity, Academy of Management Review, 25(2), 312-334, 2000.

Shehab, E. M. and Abdalla, H. S., Manufacturing cost modelling for concurrent product development, Robotics and Computer Integrated Manufacturing, 17(4), 341-353, 2001.

Shirlely, G. V., Modular Design and Manufacturing for Competitive manufacturing, Integrating Design and Manufacturing for Competitive Advantage, 88-103, 1992.

Silver, E. A., Pyke, D. F., Peterson, R., Inventory Management and Production Planning and Scheduling, John Wiley (New York), 1998.

Simpson, T.W., Maier, J.R.A. and Mistree, F., Product platform design: Method and Application, Res. Eng. Design, 13(1), 2-22, 2001

Starr, M. K., Modular Production-A New Concept, Harvard Business Review, 43(6), 131-142, 1965.

Sundgren, N., Introducing interface management in product family development, Journal of Production Innovation Management, 16(1), 40-51, 1999.

Taylor, S. G. and Bradley, C. E., Optimal ordering strategies for announced price increases, Operations Research, 33(2), 312-325, 1985.

Tseng, M. M., Jiao, J. and Merchant, M. E., Design for mass customization, CIRP Annals - Manufacturing Technology,
45(1), 153-156, 1996.

Rosenblatt, M. J. and Lee, H. L., Economic production cycles with imperfect production process, IIE Transactions, 18(1), 48-55, 1986.

Ulrich, T. K. and Eppinger, S. D., Product Design and Development, 2nd edition, New York: McGraw-Hill, Inc, 2000.

Wahab, M. I. M. and Jaber, M. Y., Economic order quantity model for items with imperfect quality, different holding costs, and learning effects: a note, Computers & Industrial Engineering, 58(1), 186-190, 2010.

Wee, H. M., Economic production lot size model for deteriorating items with partial backordering, Computers & Industrial Engineering, 24, 449-458, 1993.

Wee, H. M., Deteriorating inventory model with quality discount, pricing and partial backordering, International Journal of Production Economics, 59(1-3), 511-518, 1999.

Wee, H. M., Law, S. T., Replenishment and pricing policy for deteriorating items taking into account the time-value of money, International Journal of Production Economics, 71(1-3), 213-220, 2001.

Wee, H. M., Yu, J. and Chen, M. C., Optimal inventory model for items with imperfect quality and shortage backordering, Omega, 35(1), 7-11, 2007.

Wilhelm, B., Platform and modular concepts at Volkswagen-their effects on the assembly process, Transforming Automobile Assembly-Experience in Automation and Work
Organization, K. Shimokawa, U. Juergens and T. Fujimoto (eds), Springer, Berlin, 146-156, 1997

Yang, J. S. and Pan, C. H., Just-in-time purchasing: an integrated inventory model involving deterministic variable lead time and quality improvement investment, International Journal of Production Research, 42(5), 853-863, 2004.

Zhou, Y. W., Optimal production policy for an item with shortages and increasing time-varying demand, Journal of the Operational Research Society, 47(9), 1175-1183, 1996.