View
218
Download
0
Category
Tags:
Preview:
Citation preview
The Power of Indirect Ties in Friend-to-Friend Storage Systems
Xiang Zuo1, Jeremy Blackburn2, Nicolas Kourtellis3, John Skvoretz1 and Adriana Iamnitchi1
IEEE International Conference on Peer-to-Peer Computing 2014
1University of South Florida – Florida, USA 2Telefonica Research – Barcelona, Spain 3Yahoo Labs – Barcelona, Spain
Friend-to-Friend (F2F) Storage Systems
Users share storage resources only with friends and expect their friends behave cooperatively.
2
Limitations:
Low available storage
Low data availabilitySmall number of friends
Poor Service
Solution: Use Socially Close Indirect Relationships to Expand a User’s Friendsets
3
Question: How do we select FoFs with incentives for cooperative storage in F2F storage systems?
Answer: • Social Strength (SS) metric to measure the
strength of indirect ties.• Friendset expansion algorithm to select FoFs
with incentives.
Intuition: In real life, people rely on friends of friends (FoFs) for recommendations.
Observations from Sociology
4
The strength of a direct tie is related to the amount
of interactions.
Multiple types of interactions result in a stronger
relationship than only with one type.
The strength of an indirect tie decreases with the
length of the shortest path between the two users.
SSn(A, B) ≠SSn(B, A).
Friendset Expansion Algorithm
6
Our Friendsets Expansion Algorithm:
NOT all indirect ties of a user have incentives for cooperative storage.
i’s friendset: j, k
Social Strength
SS2(i,m)=0.39>0.33, then i’s friendset: j, k and m
i
j
k
m0.67
0.55
0.33 0.8
SS2(i,m)=0.39
n
SS2 (i,n)=0.05
2 8j
k
m
4 6
n
1
i
Each user uses a user-specific, local information of the graph that is needed in the distributed computing of F2F systems.
Improved Data AvailabilityDataset: TF2 and Friends expansion on 2 and 3 hops
7
TF2 players’ real-world average
Online/Offline traces of a week.
Timestamps are represented in
PST.
6.5 times
8
Imbalanced Workload Distribution
High-degree users are allocated higher workload than
low-degree users.
Solution: Low Degree then Low Workload (LDLW)
Summary
Proposed an indirect tie measurement—Social Strength
metric—and a friendset expansion algorithm.
Expanded friendsets improve the performance of F2F
storage systems.
Social Strength metric and the expansion algorithm can
also be used for more general socially aware systems.
10
Recommended