A Group Decision Model for Selecting Facility Layout Alternatives

1. A Group Decision Model for Selecting Facility Layout Alternatives 授課老師：林水順 老師 導讀學生：張群泓

2. Abstract • Facility layout problems (FLP) are usually treated as design problems. Lack of systematic and objective tools to compare design alternatives results in decision-making to be dominated by the experiences or preferences of designers or managers. • To increase objectivity and effectiveness of decision-making in facility layout selections, a decision support model is necessary.

3. Abstract • The enormous alternatives, various attributes, and comparison of assigned qualitative values to each attribute, form a complicated decision problem. To treat facility layout selection problems as a MADM problem, we used the linear assignment method to rank before selecting those high ranks as candidates.

4. Abstract • We modelled the application of the Nemawashi process to simulate the group decision-making procedure and help efficiently achieve agreement. • Our models are helpful to them. We use an electronics manufacturing service company to illustrate the decision-making process of our models.

5. INTRODUCTION • 1.1Facility Layouts • facility layouts,or facility layout planning, are to arrange limited space in an organization for the various use of personnel,equipments, or departments. This arrangement has great influence on the activities in the organization.

6. INTRODUCTION • 1.2 Facility Layout Problems in EMS Industry • The EMS (Electronics Manufacturing Service) industry provides OEMs (Original Equipment Manufacturers) all kinds of electronic products and customized products with lower cost and faster time-to-market. • EMS company simultaneously offers manufacture service to several OEMs. Because of product secrets, quality assurance, and other management concerns, almost all OEMs request private production areas.

7. INTRODUCTION • 1.3 Motivation and Objectives • Real facility layout planning is as follows: • Design several alternatives in a short time. New layout designs do not need to be perfect, but must be quick and flexible. • Select one of the alternatives. • Quickly execute the layout modifications. • Under this scenario, a good tool for evaluating layout alternatives is critical for making decisions and controlling modification costs

8. INTRODUCTION • 2.1 Attributes for Facility Layout Selections • After examining the shortcomings in the current decision-making process, we set these goals for developing a decision support model: • Objective decision-making. • Systematic decision making process. • Time saving. • Overall approval.

9. LITERATURE REVIEW • Lin and Sharp’s study (1999b), show that there are few studies of facility layout selection. Most studies are of facility layout design problems. • For judging facility layout alternatives, Muther (1973) proposed another set of detailed attributes. The attributes were classified into 20 groups. (P.75左邊) • Francis et al. (1992) specified 13 attributes for ranking facility layout alternatives.(P.75右邊)

10. LITERATURE REVIEW • Lin and Sharp (1999a) also developed a set of structured attributes for comparison among layout alternatives. • They classified 18 attributes into three groups. • (Including：cost，flow and environment)

11. LITERATURE REVIEW • 2.2 Qualitative Indices of Attributes

12. LITERATURE REVIEW • Lin and Sharp (1999b) also proposed some qualitative indices for his 18 attributes. • The qualitative indices are required for flow and environment groups. • In cost group, all indices use economic dollar values. Therefore, there is no need for another qualitative index.

13. LITERATURE REVIEW • 2.3 Methods for Ranking Alternatives • With this method, decision maker assigns weights to attributes, selecting the alternative with the highest score. • Since facility layout designs must satisfy various conflicting objectives, various attributes must be considered when judging among alternatives. Therefore, facility layout selection problems can be considered Multiple Attributes Decision Making (MADM) problems.

14. CONSTRUCTION OF A GROUP DECISION SUPPORT MODEL FOR FACILITY LAYOUT SELECTION

15. CONSTRUCTION OF A GROUP DECISION SUPPORT MODEL FOR FACILITY LAYOUT SELECTION • 3.2~3.3 • 這部分只要是介紹先前探討過的線性指派方法(Linear Assignment Method)並對各方案加上權重後整理出產品屬性矩陣(Product-attribute matrix)，再利用線性規劃(LP Model)方法，目的在於排序各個可選擇的方案，待方案排序完成後，最後利用Nemawashi(根回)模式來得到所有參與決策者的一致性意見。

16. CONSTRUCTION OF A GROUP DECISION SUPPORT MODEL FOR FACILITY LAYOUT SELECTION • 3.3.1 Japanese Decision Making • In general, a person or a small group is assigned the role of coordinator. This person works toward gaining consensus among participants by obtaining their opinions, carrying out negotiations, and engaging in persuasion. In Japanese, the process of gaining consensus is called Nemawashi.

17. CONSTRUCTION OF A GROUP DECISION SUPPORT MODEL FOR FACILITY LAYOUT SELECTION • After gaining consensus, the coordinator prepares a formal document detailing the proposal and circulates it among participants for consent. This document circulation stage of decision-making is called “ringi.” • This model attempts to improve the disadvantages mentioned above.

18. A Numerical Example

19. A Numerical Example • The IE engineer developed many alternatives, selecting eight possible plans. A, B, C, D, E, F, G, and H. The eight alternatives are illustrated in Figure 3. • The IE engineer applied the 18 attributes of Lin and Sharp 1999a (Table 2) and the liner assignment method of Barnade and Blin (1977) to rank these eight alternatives. • The decision maker weights each attribute in sequence. And planA-PlanH was created.

20. A Numerical Example • 在初期成本方面的改變方案排序為： • IE工程師利用前述Table2的分類與線性指派的方法，配合決策者賦予權重後排出下列順序； • Plan： C,GE,HF,D,A,B。 • 在建立產品屬性矩陣與使用LP方法後，得到最佳的計畫排序，依序為Plan：B, A, F, H, E, D, C, G。 • IE工程師挑選了前四名的計畫來做群體決策方案。 • 在相關決策者提出本身考量的意見後，IE工程師建立方案評估矩陣(E)與優先選擇條件標準的矩陣(C)，依照方案選擇矩陣(S)的結果將Plan F和Plan H剔除。

21. A Numerical Example • 承上頁 • 剩下的兩個方案(Plan A和Plan B)各有支持者，所以IE工程師必須針對這兩個方案發展新的優先選擇方案矩陣C(A)與C(B)以取得協調。 • 最後利用針對不同偏好所設計的矩陣P(A)=∣C(A)-C∣ 與P(B)=∣C(B)-C∣求出最佳方案，在此最佳方案結果為Plan A。 • Plan A為最後的決策結果。

22. CONCLUSIONS • With this model, alternatives are compared according to specific numerical values making the decision-making more objective. • This decision model considered a group decision scenario and proposed decision-making by consensus, achieving the goals of time saving and overall satisfaction. • This model will show its value once it is frequently used in the process of selecting facility layout alternatives.

23. CONCLUSIONS • We proposed a support model for selecting among facility layout alternatives in an objective and systematic way. • This model can be a useful reference in further research on facility layout selection problems.