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Research Of Peer Effects In Complex Networks

Posted on:2020-08-27Degree:DoctorType:Dissertation
Country:ChinaCandidate:P LuoFull Text:PDF
GTID:1367330590473108Subject:Management Science and Engineering
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The complex network model is the structuring and simolication of the complex systems that the entities are represented by nodes and relationships are represented by links.Scholars can analyze the network structure and network influence to illustrate the real world.This thesis focus on the peer effect nearby the target node.In existing peer influence literature,scholars mainly focus on friendship network and ignore the objective entity network including firm network and product network.The previous studies only examine the influence of network structure in the firm network or product network.Furthermore,as to the peer effect in social network,it only investigates the individuals which are linked to the target person and ignores the individuals which are not directly linked to the target one.Thus,this thesis focuses on the peer effect in complex networks,especially in obejective entity network(firm network and product network),and also considers the peer effect in application research such as link prediction method.Firstly,the new online platform is chosen,i.e.,online health community,to examine the peer effect.The number of channels to access the doctor is adopted as our dependent varaibels representing the participation degree of doctors in onli ne community.The peer effect is defined as the average number of accesss ways of target doctor's colleagues in the same department of the same hospital.With data from online health community,the results prove the significantly positive relationship between the peer effect and dependent variabel.Furthermore,in the same department,there is not only cooperation relationship but also competitive relationship existed among doctors.The cooperative relations is reflected by the postive effect of peer effect.In order to study the competitive relations,I try to examine the moderation effect of peer influence in the realtionship between doctor rating and dependent variable.The result shows the significant and negative moderation effect of peer influence.Then,to study the peer effect in objective entity network,I collect the social media data including the news data and baidu index data.Based on the text mining method and sentiment analysis method,I construct the firm co-mention network which is undirected and weighted and firm supporting or opposing network which directed and weighted.The thesis uses the baidu index as the firm influence measurements.With the firm network model,I define two variabels including peer number and weighted peer effect.The vector auto-regression model(VAR)is adopted to study the dynamic effect of peer influence variables and the firm stock performance including abnormal return and risk.The empirical results show the significant power of peer effect measurements in illustrating the firm performance.Compared with the variables in firm co-mention network,there is a stronger effect of peer effect metrics in supporting and opposing networks in predicting the firm performance.Next,I further to consider the effect of indirect links,i.e.,the influence of peers which are not directly linked to the target node but can access the target node.I collect the product review data and construct the multi-level network model including the product comparison network and users inter-communication network.In the product comparison network,I adopt the text comparative analysis to identy the product comparative relationship and use the sentiment analysis method to obtain the relationship weight.Moreover,I also consider the users communication structure in product review and construct the user inter-communication network.Based on our multi-level product network model,I construct the transitive peer effect which includes the influence of nodes linked to the target and nodes not linked to the target node but can access the target node.With the product sales ranking data,I use the regression and classification methods to exmaine the impact of transitive peer effect in affecting the product sales ranking.The empirical results show the significant influence of transitive peer effect and prove the strongest ability of transitive peer effect in illustrating the product sales.Lastly,I also apply the peer effect in construct link prediction methods in complex network.With the construction of node utility,I cosider the effects of different peers and construct four different link prediction models.With the existing network state,I use the logistic regression model to estimate the coefficients in the models.Then,with the real social network data,I compare the performance of our proposed link prediction methods and the existing link prediction methods.The results show the superiority of our proposed methods.I also apply our proposed link prediction methods in analyzing the evolution of social networks and friends recommendation.With collecting real data,this thesis examines the peer effect not only in the friendship network such as online health community but also in objective entity network including the product network and firm network.In friendship network and firm network,I construct the peer effect measurements including the influence of peers which are linked to the target node.While in the product network and link prediction methods,except the nodes directly linked to the target one,I also consider influence of nodes which have access to the target node.In this thesis,I prove the significant influence of peer effect in affecting the doctor behavior,firm performance in stock market and product sales ranking.More,I also construct the link prediction methods considering the peer effect and prove the validity of our methods.Our thesis not only contributes to the existing social influence and complex literature,but also provides some insights in the practical implications.
Keywords/Search Tags:peer effects, complex network, online health community, firm network, product network, link prediction
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