An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing
-
Upload
alejandro-rivero -
Category
Science
-
view
36 -
download
0
Transcript of An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing
![Page 1: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/1.jpg)
An Initial Homophily Indicator to Reinforce Context-Aware Semantic
ComputingA. Rivero-Rodriguez, P. Pileggi, O. Nykänen
Tampere University of TechnologyTampere, Finland
June 3, 2015Riga, LatviaCICSyN 2015: Computational Intelligence, Communication Systems and Networks
![Page 2: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/2.jpg)
This talk describes the benefits of using social network analysis, in particular homophily, in context-aware systems
Context SNA/Homophily Indicators
2
3.6.2015
![Page 3: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/3.jpg)
What is context?
Context is any information that can be used to characterize the situation of an entity, where an entity can be a person, places, or physical or computational object1.
Context is the sum total of what is known about an individual along with what he or she is currently experiencing.
3
3.6.20157th International Conference CICSyN 2015
Context
![Page 4: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/4.jpg)
Context-aware system can be found everywhere, even in your phone…
4
3.6.20157th International Conference CICSyN 2015
Context
![Page 5: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/5.jpg)
Social Network Analysis
Social Network Analysis (SNA) focuses on the discovery and evolution of relations among entities (people, organizations, activities, etc.) [21].
We want to use SNA techniques to understand existing systems. It can be used for modelling for link prediction etc.
SNA is not solely useful for understanding a system, but for others tasks such as Prediction, Recommendation, etc. For example, Amazon’s recommender system.
5
3.6.2015
SNA
![Page 6: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/6.jpg)
Homophily states that connections between similar people happens at a higher rate than among dissimilar people
6
3.6.2015
SNA
Network that exhibits homophily
![Page 7: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/7.jpg)
Homophily is ubiquitous in social systems.
Network of romantic relationships in a highschool exhibits:inverse homophily according to genderdirect homophily according to age
Two mechanisms underlying homophilySelectionSocial influence (socialization)
7
3.6.2015
SNA
![Page 8: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/8.jpg)
Measuring Homophily in social network
8
3.6.2015
Indicator
n number of present edges in G.p number of possible edges in G.Proportion of edges in the network
Proportion of homophily edges.
Proportion of heterophily edges.
![Page 9: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/9.jpg)
Comparison of homophily indicators
Existing affinity indicator Our homophily indicator
9
3.6.2015
Indicator
+1
-1
0
Homophily
Heterophily+1
∞
0Heterophily
Homophily
Difficult to interpret and utilizeWhat is aff value for a system with only homophilic connections?
Easier to interpret.Homophily and heterophily are equally important.
![Page 10: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/10.jpg)
Experimenting with hom indicators. Description of the nodobo dataset
Smartphone social interaction data27 senior high-school studentsData collected for 5 months: Sep’10 – Feb’11 (only considered 105 days with data)We used the bluetooth data and build a graph G
• Each user is a node in G• There is a link between two users if they have been in
proximity for more than 60 min a day. (preanalysos)
10
3.6.2015
Indicator
![Page 11: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/11.jpg)
Experiment settings
Homophily conditions: Two users are expected to be connected if they have more than f friends in common
We have discretize the 105 days of data into W periods of lenght L, so that
11
3.6.2015
Indicator
![Page 12: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/12.jpg)
Experiment settings
Homophily conditions: Two users are expected to be connected if they have more than f friends in common
We have discretize the 105 days of data into W periods of lenght L, so that
Several experiments, such as:• Experiment A: W=15, f=2• Experiment B: W=5, f=3
12
3.6.2015
Indicator
System parameters
![Page 13: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/13.jpg)
Results & Observations13
3.6.2015
Indicator
Figure 2. Aff and Hom indicator values reported for Experiment A.
Figure 3. Aff and Hom indicator values reported for Experiment B.
![Page 14: An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing](https://reader035.fdocuments.net/reader035/viewer/2022070523/58ed94a61a28ab62018b4681/html5/thumbnails/14.jpg)
Conclusions & Future Work
We propose an homophily indicator that overcomes the weaknesses of others proposed in the literature. It is easier to understand and interpret, potentially useful in existing context-aware systems.
Future work includes• the extension of the indicator to account for time periods, • the development of model driven solutions based for
context inference based on our Hom indicator.
14
3.6.2015
Indicator
Alejandro [email protected]