Posts Tagged ‘Student’

spotting – Social Network-based Location Recommender System

October 29th, 2009

User interface of the spotting location recommender system

User interface of the spotting location recommender system

Several weeks ago, my student Reto Hodel who I’m supervising currently published a really cool and easy-to-use Web application that lets you find new potentially interesting locations such as bars, restaurants or clubs based on their social relationships within the Facebook community. In other words, your recommendations are generated depending on your friends, your different participating n-cliques, your explicit and implicit trusted trendsetters and other social network analysis based metrics. This Social Network-based location recommender system is called spotting.

In this master thesis, he built a Web applications that uses the people’s Social Network at Facebook to generate the location recommendations. Based on the data gathered by the Web application we analyze what SNA metrics are suitable for generating such recommendations. We are still investigating this research questions. As soon we get som e more insights we plan to add them to the Web application such that people can benefit from better recommendations.

If you are interest in having a look into the Web application then please just check out the following link:
http://seal.ifi.uzh.ch/spotting

You may want to join the spotting group at Facebook. So far, we only provide locations from Zurich.

OMORE – Personal Cross-Site Movie Recommender System Implemented as Mozilla Firefox Add-On

August 15th, 2009

OMORE recognizes a Movie Web site and adds automatically rating and recommendation functionality to a Movie Web site at Amazon.com

OMORE recognizes a Movie Web site and adds automatically rating and recommendation functionality to a Movie Web site at Amazon.com


Online stores or Web page bring information about a myriad of items such as books, CDs, restaurants or movies at the user’s fingertips. Although, the Web reduces the barrier to the information, the user is overwhelmed by the number of available items. Therefore, online stores provide recommender systems that aim to guide the user to relevant items. However, recommender systems are generally limited to the Web page’s content and the explicit or implicit ratings provided by the users on the particular Web page. User are lazy when it comes to repeat providing rating information to recommender systems on other Web pages. That is a typical lock-in situation based on high transaction costs such that people are addicted to one or at least a limited number of Web pages.
People are required to have an account on a particular Web page before being provided with interesting recommendations. People may have concerns about providing explicit or implicit ratings on items that may expose some delicate details about their privacy.
But many rather small online stores do not even provide recommendations.

Thus, we need a recommender system that (1) recognizes items over various Web pages as the same and remembers the ratings for those, (2) applies algorithms to provide recommendations and (3) smoothly integrates the rating and recommendation functionality directly in the Web site. We found the basic infrastructure for such a recommender system in the Firefox Add-on API and WEKA, a common data mining library.
We formulated these requirements as a master thesis. We were very happy to engage Tobias, an excellent master student.

The described recommender system implemented as Firefox Add-on can be downloaded at s.e.a.l. group site.

Abstract

Online stores and Web portals bring information about a myriad of items such as books, CDs, restaurants or movies at the user’s fingertips. Although, the Web reduces the barrier to the information, the user is overwhelmed by the number of available items. Therefore, recommender systems aim to guide the user to relevant items. Current recommender systems store user ratings on the server side. This way the scope of the recommendations is limited to this server only. In addition, the user entrusts the operator of the server with valuable information about his preferences.

In this thesis, we introduce our recommender system OMORE, a private, personal movie recommender, which learns the user model based on the user’s movie ratings. To preserve privacy, OMORE is implemented as a Mozilla Firefox add-on, which stores the user’s ratings and the learned user model locally at the client side. Although OMORE makes use of the movie features, which are provided by the different movie pages on the Amazon.com, Blockbuster, Netflix and Rotten Tomatoes.

Zusammenfassung

Online-Geschäfte und Web Portale bieten einem Kunden im Allgemeinen eine riesige Auswahl an Filmen oder Büchern an. Oftmals ist dieser aber mit der riesigen Auswahl an vorhandenen Artikeln überfordert und braucht Unterstützung, um die für ihn interessanten Produkte auch wirklich zu finden. Empfehlungssysteme haben sich bewährt und sind sehr erfolgreich beim Filtern von grossen Datenbeständen. Doch nur wenige Portale wie das Online-Geschäftshaus Amazon bieten einem Kunden ein solches Empfehlungssystem zur aktiven Unterstützung an.

In der Regel basieren die von einem Empfehlungssystem vorgeschlagenen Produktempfehlungen auf den Bewertungen von anderen Kunden. Diese werden in den heutzutage verfügbaren Empfehlungssystemen häufig von den Anbietern eines Web Portals individuell verwaltet, so dass sie dadurch nicht auf anderen Portalen wie zum Beispiel dem Online DVD Verleih Netflix verwendet werden können. Zudem vertraut ein Kunde einem Anbieter eines solchen Portals oft sehr vertrauliche Informationen über sein Kaufverhalten und seine Präferenzen an.

In dieser Arbeit soll daher ein portalunabhängiges Empfehlungssystem entwickelt werden, welches direkt im Web-Browser integriert ist. Das von uns auf den Namen OMORE getaufte Empfehlungssystem, ist ein auf Sicherheit ausgerichtetes personalisiertes Empfehlungssystem für Filmliebhaber, welches als Erweiterung für den Mozilla Firefox Browser angeboten wird. Es lernt die Benutzerpräferenzen basierend auf den Filmbewertungen eines Benutzers und speichert das gelernte Model der Benutzerpräferenzen lokal auf dem System des Benutzers ab. Dadurch wird sichergestellt, dass die Benutzerpräferenzen vor unbefugtem Zugriff geschützt sind. OMORE bietet einem Benutzer portalübergreifende Empfehlungen an, wobei die aktuelle Implementierung die Filmseiten von Amazon.com, Blockbuster, der Internet Movie Database, Netflix und Rotten Tomatoes umfasst.

Tobias Bannwart: “OMORE – Private, Personal Movie Recommendations implemented in a Mozilla Firefox Add-on“, ed. by Amancio Bouza, Gerald Reif and Harald C. Gall, University of Zurich, July 2009. (master thesis)

Downloads:

My first Bachelor student finished his thesis about “Purple Leaf – Evaluation of the Adoption of New Features in a Web-Based Social Network”

January 4th, 2009

Visitors of Purple Leaf parties. People in the center visited quite all parties. The outliers generally only visited few ones.

Participants resp. party people on the various partys


Together with Marc Vontobel’s main advisor Gerald Reif, I successfully advised and supported Marc with his bachelor thesis. He was my first student I advised at all. He reenginered Purple Leaf – a party portal – and investigated the impact of social relations among people with respect to acceptance rate of new features on a web page. At the time he finished with his thesis, the community of Purple Leaf consisted of several thousands of people.
It seems that one rather accepts and adopts a new feature when a friend already adopted it. It seems that the inhibition threshold is much lower due to the fact, that people trust their friends and thus, trust the feature and it added value. Marc did a great job that could not be expected from a Bachelor student, starting from the software engineering skills to the data gathering and complex Social Network Analysis (SNA). But he was already prepared from our precedent seminar on “Trust and Recommendation in Social Networks”.

We were surprised as he delivered not only his thesis but also a complete picture book with fantastic analysis of differenc aspects of his party community. He discovered the core group of party people being on most parties, the latent semantics among different music styles and drinks.

Abstract

Purple Leaf is a social network which offers its member several possibilities to personalize its exclusive events by providing them unique online services. After the size of our platform suddenly increased from 300 initially invited guests to a multiple, we were obliged to completely revise the platform and enlarge our range of services. To embed these new services smoothly into the existing web presence, we fully restructured the application and changed the basis to a modern web framework. After that makeover, we designed five other services which we targeted to increase the customer loyalty and the entertainment value of our platform. Because new features are often not instantly accepted by existing users, we developed an integrated concept for boosting the acceptance of novel functionality. This concept is based on the technology acceptance model which was developed by Davis (1986). The model postulates that the actual use of a new feature is solely based on external factors. On the one hand, there are factors which influence the ‘perceived ease-of-use’ and on the other hand some that have impact on the ‘perceived usefulness’. In order to foster the perceived ease-of-use, we developed several usability concepts and tried to figure out how Web 2.0 features can help to simplify different processes. Beside the creation of intuitive user interfaces and plain procedures, we worked on an elaborated data and application structure which itself also contributed a big part to the simplicity of the new functionality. After we had embedded the services into our Internet portal, we started to analyze the acceptance of one new feature: ‘The most favored Guest’. This service allows every sign up member to define his personal list of favored guests for an upcoming event. Once the selected users are informed about their election, they, in turn, have the chance to define their own list. After a first round of selection, we tried to boost the personal acceptance of our members by providing specific incentives. Beside the active interventions into the process of adoption, we also analyzed a passive phenomenon: Does some kind of peer pressure exist within virtual cliques? If so, there might emerge some interesting changes in common marketing strategies which could narrow down the target audience to some single users of the network. In addition, we visualized some of the encountered situations and putted them together in an illustrated book as supplement to this paper.

Marc Vontobel: “Purple Leaf – Evaluation of the Adoption of New Features in a Web-Based Social Network”, ed. by Gerald Reif, Amancio Bouza, Harald C. Gall, University of Zurich, December 2008. (bachelorsthesis)