在生活上我們有常常會看到婚紗街、店子街、精品街等店家群聚在一起開店。這種商業型態能夠提高顧客的便利性，像是顧客在店家和店家之間的移動成本降低、店家越多找尋到喜愛物品的機率提高。店家群聚群聚在一起開店最主要的目的是能夠吸引更多的消費者前往購買，能讓他們的利潤比單獨開設店面時能獲取更多的利潤。但是並不是店家只要群聚在一起開店就能獲取更多的利潤，店家彼此之間會互相瓜分顧客，或是實行價格戰，低價促銷，導致獲得的利潤比單獨開設店面時能獲取更多的利潤還低，使得店家寧願選擇單獨開設店面，不參與群聚。
我們發展舊有的消費者剩餘模型，試圖去解釋群聚效應對顧客所帶來的正面效用，且所發展出來的新模型有部分是類似牛頓的萬有引力模型的概念。之後我們假設顧客均勻分布於市場，利用這個新模型我們發現店家是否有受到群聚效應的影響，找尋店家的潛在顧客可以讓店家做有效的行銷，新店家若要進入此市場，在市場的已知店家數目下、價格未知或已知的情況下，選擇和原有店家群聚在一起開店，或選擇遠離單獨開店。之後我們試圖去分析在一個市場內店家的數目影響店家群聚或選擇遠離單獨開店和群聚效應他所影響的範圍，利用店家和店家的距離來依據。
最後我們的研究目的就是希望能幫助店家找尋能獲得最大利潤的位置。在過去的文獻中敘述群聚效應大部分著重於工業的群聚效應，對於商業的群聚效應著墨較少，發展數學模型更是少，而這正是我們這篇研究所著重的部分。

　　In our life, we usually find Weeding Street, Electronic Street, and Jewelers’ Row on where the stores run the shop together. In this business type, customer could be much more convenient. Such as the cost of move between stores can decrease and if there are more stores, customers find their buyable product increasingly. For stores, the main reason is that they can attract more customers coming and purchasing. It means the stores can get more profits than when they run the shop alone. But store cluster does not represent to get more profits certainly. Between stores, they could divvy up customers, or price competition. Above could cause that stores choose not to cluster because the profit is less than when they run the shop alone.
　　We develop original customer surplus to explain cluster effect make positive for customers. And the idea is similar to Newton’s law of gravity. We assume customers are distributed the plane according to uniform distribution. We use the new model to find stores are influenced by cluster effect. We find potential customers to advertise effectively. Find the best location when the new store wants to enter this market. We try to analysis the number of stores influences store cluster and distance/range is influenced by cluster effect.
　　Finally, our research objective is search the best location where the stores could get more profits. In the past literatures, they states industry cluster effect much. But store cluster effect and developing mathematics model is less, and this is our main concept in our study.

1.André De Palma, Victor Ginsburgh and Jacques-François Thisse, (1987), “On Existence of Location Equilibria in the 3-Firm Hotelling Problem”. The Journal of Industrial Economics, Vol. 36, No. 2, pp. 245-252.
2.Dan O’dono Ghue and Bill Gleave, (2002), “A note on Methods for Measuring Industrial Agglomeration”. Regional Studies, Vol. 38. 4, pp.419-427.
3.Hideo Konishi, (2005), “Concentration of Competing Retail Stores”. Journal of Urban Economics, Vol. 58, pp. 488-512.
4.Ian Ayres, (1985), “Rationalizing Antitrust Cluster Markets”. The Yale Law Journal, Vol. 95, No.1, pp.109-125.
5.Jeffrey H. Fischer and Joseph E. Harrington, (1996), “Product Variety and Firm Agglomeration”. The RAND Journal of Economics, Vol. 27, No. 2, pp. 281-309.
6.Jacques-Franc_ois Thisse, (1998), “Competition in Multi-characteristics Spaces: Hotelling Was Almost Right”. Journal of Economic Theory, Vol. 78, pp. 76-102.
7.Joel A. C. Baum and Heather A. Haveman, (1997), “Love they Neighbor? Differentiation and Agglomeration in the Manhattan Hotel Industry, 1898-1990”. Administrative Science Quarterly, Vol. 42, No. 2, pp. 304-338.
8.Ji Nian, Hu Jia, Yu Qian, (2010), “Expanded Hotelling Model with Introduction of Informative Advertising”. IEEE, Vol. 1, pp.493-496.
9.Kelvin Lancaster, (1990), “The Economics of Product Variety: A Survey”. Marketing Science, Vol. 9, No. 3, pp. 189-206.
10.K. Sivakumar, (1995), “Role of Price and Quality Tiers on the Cluster Effect in Brand Choice”. Marketing Letters, Vol. 6, pp. 265-273.
11.Luca Lambertini, (1997), ”Unicity of the Equilibrium in the Unconstrained Hotelling model”. Regional Science and Urban Economics, Vol. 27, pp. 785-798.
12.Luiz A. Dasilva, (2000), “Pricing For Qos-enabled Networks : A Survey”. IEEE, Vol. 3, pp. 2-8.
13.Maria Ana Vitorino, (2012), “Empirical Entry Games with Complementarities: An Application to Shopping Center Industry”. Journal of Marketing Research Vol. XLIX, pp. 175-191.
14.Newton, (1687), “Philosophiæ Naturalis Principia Mathematica”.
15.Paul Benneworth and Nick Henry, (2003), “Where Is the Value Added in the Cluster Approach? Hermeneutic Theorising, Economic Geography and Clusters as a Multiperspectival Approach”. Urban Studies, Vol. 41, pp. 1011–1023.
16.Ronald Balvers, LaZLO Szerb, (1994), “Location in the Hotelling Duopoly Model with Demand Uncertainty”. European Economic Review Vol. 40, pp. 1453-1461.
17.Steffen Brenner, (2001) “Hotelling Games with Three, Four, and More Players”. International Journal of Industrial Organization, Vol. 18, pp. 7-22.
18.Su, X and Zhang, F, (2008), “Strategic Customer Behavior, Commitment, and Supply Chain Performance”. Management Science, Vol. 54, No. 10, PP. 1759-1773.
19.Wiley Periodicals, (2005), “Consumers in a Multichannel Environment: Product utility, Process utility, and Channel choice”. Journal of Interactive Marketing Vol.19 pp.12-30.