The plethora of talks and presentations taking place at academic conferences makes it difficult, especially for young researchers to attend the right talks or discuss with participants and potential collaborators with similar interests. Participants may not have a priori knowledge that allows them to select the right talks or informal interactions with other participants. In this paper we present the context-aware mobile recommendation services (CAMRS) based on the current context (whereabouts at the venue, popularity and activities of talks and presentations) sensed at the conference venue. Additionally, we augment the current context with the academic community context of conference participants which is inferred by using social network analysis and link prediction on large-scale co-authorship and citation networks of participants. By combining the dynamic and social context of participants, we are able to recommend talks and people that may be interesting to a particular participant. We evaluated CAMRS using data from two large digital libraries - the DBLP and CiteSeerX, and participants from two conferences - ICWL 2010 and EC-TEL 2011. The result shows that the new approach can recommend novel talks and helps participants in establishing new connections at conference venue.

1. TeLLNet
Enhancing Academic Event
Participation with Context-aware
and Social Recommendations
Manh Cuong Pham, Dejan Kovachev, Yiwei Cao,
Ghislain Manib Mbogos and Ralf Klamma
RWTH Aachen University
Advanced Community Information Systems (ACIS)
Lehrstuhl Informatik 5
(Information Systems)
{pham|kovachev|cao|manib|klamma}@dbis.rwth-aachen.de
Prof. Dr. M. Jarke
I5-CMP-0812-1 This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

2. TeLLNet Advanced Community Information
Systems (ACIS)
Responsive
Web Engineering Community
Web Analytics
Open
Visualization
Community
and
Information
Simulation
Systems
Community Community
Support Analytics
Lehrstuhl Informatik 5
Requirements
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-2
Engineering

3. TeLLNet
Motivation
 Main reasons to participate in academic conferences:
– To get informed about the state-of-the-art
– To present own research, and get reactions from peers
– To have papers published in the conference proceedings
– To meet others working in the same domain
– Quickly exchange a variety of experiences
– Establish personal relationships
– Lay the foundation for future collaboration
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-3

4. TeLLNet
Motivation
 E.g. ACM SIGGRAPH 2010
105 sessions
1000 participants
5 days Sightseeing & more
? ?
Room 342: workshop
?
Auditorium: keynote
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke Room 204: paper session Hall: poster session Room 048: round table
I5-CMP-0812-4

5. TeLLNet
Filtering and Selection: Researchers
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-5

6. TeLLNet
Filtering and Selection: Events
✔
?
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-6

7. TeLLNet
Research 2.0
 Support tools already exist in many domains
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-7

8. TeLLNet
Context-Aware Mobile Recommender
System for Conference Participants (CAMRS)
 Goals
– A mobile recommendation service for conference participants
– Talk and researcher recommendations
 Spatio-temporal context
– Whereabouts at the venue
– Popularity and activities of talks and presentations
 Social context – Academic community context
– SNA and link prediction on large-scale co-authorship and citation
networks of participants
– Analysis of the collaboration ties existing among the participants
 Mobility
Lehrstuhl Informatik 5
(Information Systems)
– The service runs on participants‘ smartphones
Prof. Dr. M. Jarke
I5-CMP-0812-8 – On-site real-time recommendations

9. TeLLNet Mobile Services for
Conference Participants
System Features
Conference Navigator Schedule, community-based talk recommendation based on
[Farzan, 2008] individuals‘ schedules
I-KNOW Conference Assistant I-KNOW conference program browsing, planning; real time
(KNOW Center, TU Graz, Austria) tracking of talks
ACM UIST Conference App ACM UIST conference program browsing, planning
(RWTH Aachen, Germany)
Conference App ICSE, MSR, etc., conference program browsing, real time
(Microsoft Research) tracking of talks
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-9

10. TeLLNet
Social Mobile Services
 Accessing online social networking services through mobile devices to
facilitate social interaction
 Current approaches
System Features Techniques
WhozThat Social networking ID sharing, content Bluetooth, WiFi, Online social
[Beach, 2008] adaptation networking access
SIM-Mee Bussiness card exchange, nearby Bluetooth, WiFi, NFC
[Albert, 2009] contacts finding
CenceMe Publishing sensing presence (status, Bluetooth, GPRS, WiFi
[Miluzzo, 2007] activities, location, etc.) of users to social
neworking sites, analysis of historical
Lehrstuhl Informatik 5
sensing data
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-10

11. TeLLNet Context-Aware Mobile
Recommendation Services
 Multidimensional recommendation model (MD) [Adomavicius 2005]
- CF: 2-dimensions, e.g., user and item
- MD: n-dimentions, e.g., user, item, time, location, etc.
- Incorporate contextual information: reduce n to two dimentions
 Current approaches
System Features Techniques
CARS Learning user context from interaction Follows MD model
[Bouzeghoub, 2009] history, building active user profiles
UbiComp Display people information in RFID tags and readers
[McCarthy, 2001] presentation, discussion and other social
(informal events) at conferences
PeerHood Dynamically creates and manages social Bluetooth, WLAN, GPRS
Lehrstuhl Informatik 5
[Karki, 2009] network of mobile devices based on communication
(Information Systems)
Prof. Dr. M. Jarke
dynamic profile matching
I5-CMP-0812-11

12. TeLLNet Conflation of Contextual
and Social Information
 Dynamic preference matrix
- User-talk matrix: schedule and location of
participants
- Projection of user-talk matrix on time
dimension
 Neighborhood formulation
- Pre-compute similarity using link-
prediction measure Jaccard based on
citation and co-authorship networks
- Select top k similar authors
CAMRS recommendation process
 Recommendation generation:
- Talk recommendation: apply CF on preference matrix
Lehrstuhl Informatik 5
(Information Systems)
- People recommendation: top similar authors (no-direct links) nearby
Prof. Dr. M. Jarke
I5-CMP-0812-12

13. TeLLNet
Neighborhood Formulation
 Link prediction on co-authorship and citation networks
 Two types of neighbor
- Direct peer: two authors who are directly connected, similarity equal to 1
- In-direct peer: Jaccard measure (other measures are possible)
| (u ) (v ) |
S (u , v )
| (u ) (v ) |
where (u ) is the set of direct peer of author u
 Overall similarity: linear combination of link prediction measures on two
networks
S (u, v) * Scoauthor (u, v) (1 ) * Scitation (u, v)
Lehrstuhl Informatik 5
(Information Systems)
where 0 1 is the parameter to control the strength of coauthorship. In the
Prof. Dr. M. Jarke
I5-CMP-0812-13 evaluation, we set 0.7

14. TeLLNet
CAMRS Prototype
 RESTful Web Service
 Oracle 11g database
 Android app
 Location sensing:
- At least at room level
- Currently used a QR code scanner on
Android smartphones
- Other possible techniques:
RFID, WiFi, etc.
 Conference program
- XML schema to handle conference program CAMRS Mobile Client
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-14

15. TeLLNet
Data Sets
 DBLP (http://www.informatik.uni-trier.de/~ley/db/)
- 788,259 author’s names
- 1,226,412 publications
- 3,490 series (conferences, workshops, journals)
 CiteSeerX (http://citeseerx.ist.psu.edu/)
- 7,385,652 publications (including publications in reference lists)
- 22,735,240 citations
- Over 4 million author’s names
 Combination
- Canopy clustering [McCallum 2000]
- Result: 864,097 matched pairs
- On average: series cite 2306 and are cited 2037 times
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-15

16. TeLLNet Knowledge Network:
the Visualization
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-16 - AERCS (http://bosch.informatik.rwth-aachen.de:5080/AERCS/)

17. TeLLNet Evaluation 1:
ICWL 2010 Simulation
 Testbed setup
- Choose 6 evaluators equipped with Android smartphones
- Program: 15 tracks (3 keynotes, 6 paper sections, 6 workshops) with 128
participants
- Three rooms with QR code
 Procedure
- Conference program was run in real time
- Evaluators moved around between three rooms
- Recommendations were logged for later analysis
 Results
- Real time recommendations
- Performance:
- Talk recommendations are helpful
Lehrstuhl Informatik 5 - People recommendation: some are known; evaluators agreed to interact with recommended
(Information Systems)
Prof. Dr. M. Jarke
(unknown) people
I5-CMP-0812-17

18. TeLLNet Evaluation 2:
ECTEL 2011
 Testbed setup
- A poster was presented in ECTEL 2011
- ECTEL program was imported into CAMRS
- Android smartphones were available to participants at the conference
 Procedure
- Conference program was run in real time
- Participants can login and get recommendations
- Mobility was not evaluated
- A survey was sent after the conference
 Results
- 20 feedbacks with positive comments
- „The talk recommendations were strikingly accurate“,
„ Some of the recommendations were surprising, but it remains unclear, why they have been
chosen“, etc.
Lehrstuhl Informatik 5
(Information Systems) - People recommendation: some are known personally;
Prof. Dr. M. Jarke
I5-CMP-0812-18

19. TeLLNet
Conclusions and Future Work
 Combination of research history and contextual information
– Link prediction on co-authorship and citation networks to find similar researchers
– Dynamic implicit preference data of users on talks/presentations
 Two case studies verify the recommendations
 Open issues
– Topic drift: user interest changes over time
– Diversity in user interest: user may be interested in different topics
 On-going work
– Community mining from citation and collaboration networks: non-overlapping and
overlapping communities
– Topic modeling: enhance communities with topics
– Further evaluations on more conferences
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-19

20. TeLLNet
Thank you for your attention!
Questions?
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-CMP-0812-20