Application Scenarios Recommender systems [131 Recommendations have found its usage in many emerging specific applications, such as social matching systems Graph search is a useful tool for recommendations a headhunter wants to find a biologist (Bio)to help a group of software G engineers(sEs) analyze genetic data DM1 To do this, (s)he uses an expertise HRI Bio1 recommendation network g. as Bi depicted in g, where All Al2 v a node denotes a person labeled SE1 B102 Bio3 with expertise, and SE2 DM2 an edge indicates recommendation AlI DM Alk DMK e.g., HR, recommends Bio,, and Al, recommends DM1 10Application Scenarios 10 • Recommendations have found its usage in many emerging specific applications, such as social matching systems. • Graph search is a useful tool for recommendations. Recommender systems [13] – A headhunter wants to find a biologist (Bio) to help a group of software engineers (SEs) analyze genetic data. – To do this, (s)he uses an expertise recommendation network G, as depicted in G, where ✓ a node denotes a person labeled with expertise, and ✓ an edge indicates recommendation, e.g., HR1 recommends Bio1 , and AI1 recommends DM1