線上社會網絡連結強度之衡量

Abstract

在過去關於社會網絡的研究中，發現了許多它所具備的特性，例如小世界現象、群聚現象等，讓人們得以認識這個由「人」所構成的網絡，並將之運用在其他各種領域。但是，大部分的研究僅僅考慮連結的存在與否，關於連結強度的探討卻是較為缺乏的，由於人與人之間的關係並非一致或對等的，我們將網絡視為有方向性、且連結帶有「重量」的，試著從中觀察連結強度在社會網絡巨觀特性中所扮演的角色。於是，我們蒐集了部落格網站中的資料，記錄使用者間各種互動，定義了不同的關係，並計算其互動的次數作為連結的強度。我們首先觀察在不同的關係定義之下，連結強度的分布狀況，接著比較使用者所擁有的連結數和其強度總和，提出了另一種衡量使用者的方法。我們也在計算平均最短路徑、群聚係數時，將連結強度一起考慮進來，發現了過去未曾注意到的有趣現象。最後，我們首次比較了兩節點間雙方面的連結強度，證明了在社會網絡中使用者間的互動是有其對稱性和相關性的。我們相信這份關於連結強度的實證研究，讓我們對於社會網絡的巨觀現象能有進一步的了解，也給後續的研究一個新的方向。

In the previous studies, people have found many properties of social network, such as “small world phenomenon” and high clustering. But, most of the researches merely consider whether this is a tie, rather than the strength of tie. Since the relationship between people is not identical or symmetric, we regard the network as a directed graph, and the tie on it have its “weight”. Under this circumstance, we wonder what is the role of tie strength in those properties of social network. Therefore we parse data of a blogging site, and record the interaction between the users on it. After defining different types of relationship, we then count the times of action as the strength of tie. First, we examine the distribution of tie strength, from both network and users’ view, and then compare to the distribution of link degree. To evaluate the node, we propose a new measurement, calculated by the strength of tie. Next, we take tie strength into account of average shortest path and cluster coefficient. We find out some interesting characteristics people did not pay attention to before. Finally, we examine the symmetry of the network and analyze the correlation between tie strength of nodes for the first time. We believe that this empirical study of tie strength can help us further understand the macro characteristics of social network, and provide a new perspective for the future researches.