181,449 research outputs found
Use of implicit graph for recommending relevant videos: a simulated evaluation
In this paper, we propose a model for exploiting community based usage information for video retrieval. Implicit usage information from a pool of past users could be a valuable source to address the difficulties caused due to the semantic gap problem. We propose a graph-based implicit feedback model in which all the usage information can be represented. A number of recommendation algorithms were suggested and experimented. A simulated user evaluation is conducted on the TREC VID collection and the results are presented. Analyzing the results we found some common characteristics on the best performing algorithms, which could indicate the best way of exploiting this type of usage information
Adaptive Channel Recommendation For Opportunistic Spectrum Access
We propose a dynamic spectrum access scheme where secondary users recommend
"good" channels to each other and access accordingly. We formulate the problem
as an average reward based Markov decision process. We show the existence of
the optimal stationary spectrum access policy, and explore its structure
properties in two asymptotic cases. Since the action space of the Markov
decision process is continuous, it is difficult to find the optimal policy by
simply discretizing the action space and use the policy iteration, value
iteration, or Q-learning methods. Instead, we propose a new algorithm based on
the Model Reference Adaptive Search method, and prove its convergence to the
optimal policy. Numerical results show that the proposed algorithms achieve up
to 18% and 100% performance improvement than the static channel recommendation
scheme in homogeneous and heterogeneous channel environments, respectively, and
is more robust to channel dynamics
An Accuracy-Assured Privacy-Preserving Recommender System for Internet Commerce
Recommender systems, tool for predicting users' potential preferences by
computing history data and users' interests, show an increasing importance in
various Internet applications such as online shopping. As a well-known
recommendation method, neighbourhood-based collaborative filtering has
attracted considerable attention recently. The risk of revealing users' private
information during the process of filtering has attracted noticeable research
interests. Among the current solutions, the probabilistic techniques have shown
a powerful privacy preserving effect. When facing Nearest Neighbour attack,
all the existing methods provide no data utility guarantee, for the
introduction of global randomness. In this paper, to overcome the problem of
recommendation accuracy loss, we propose a novel approach, Partitioned
Probabilistic Neighbour Selection, to ensure a required prediction accuracy
while maintaining high security against NN attack. We define the sum of
neighbours' similarity as the accuracy metric alpha, the number of user
partitions, across which we select the neighbours, as the security metric
beta. We generalise the Nearest Neighbour attack to beta k Nearest
Neighbours attack. Differing from the existing approach that selects neighbours
across the entire candidate list randomly, our method selects neighbours from
each exclusive partition of size with a decreasing probability. Theoretical
and experimental analysis show that to provide an accuracy-assured
recommendation, our Partitioned Probabilistic Neighbour Selection method yields
a better trade-off between the recommendation accuracy and system security.Comment: replacement for the previous versio
A probabilistic model to resolve diversity-accuracy challenge of recommendation systems
Recommendation systems have wide-spread applications in both academia and
industry. Traditionally, performance of recommendation systems has been
measured by their precision. By introducing novelty and diversity as key
qualities in recommender systems, recently increasing attention has been
focused on this topic. Precision and novelty of recommendation are not in the
same direction, and practical systems should make a trade-off between these two
quantities. Thus, it is an important feature of a recommender system to make it
possible to adjust diversity and accuracy of the recommendations by tuning the
model. In this paper, we introduce a probabilistic structure to resolve the
diversity-accuracy dilemma in recommender systems. We propose a hybrid model
with adjustable level of diversity and precision such that one can perform this
by tuning a single parameter. The proposed recommendation model consists of two
models: one for maximization of the accuracy and the other one for
specification of the recommendation list to tastes of users. Our experiments on
two real datasets show the functionality of the model in resolving
accuracy-diversity dilemma and outperformance of the model over other classic
models. The proposed method could be extensively applied to real commercial
systems due to its low computational complexity and significant performance.Comment: 19 pages, 5 figure
A Personalized System for Conversational Recommendations
Searching for and making decisions about information is becoming increasingly
difficult as the amount of information and number of choices increases.
Recommendation systems help users find items of interest of a particular type,
such as movies or restaurants, but are still somewhat awkward to use. Our
solution is to take advantage of the complementary strengths of personalized
recommendation systems and dialogue systems, creating personalized aides. We
present a system -- the Adaptive Place Advisor -- that treats item selection as
an interactive, conversational process, with the program inquiring about item
attributes and the user responding. Individual, long-term user preferences are
unobtrusively obtained in the course of normal recommendation dialogues and
used to direct future conversations with the same user. We present a novel user
model that influences both item search and the questions asked during a
conversation. We demonstrate the effectiveness of our system in significantly
reducing the time and number of interactions required to find a satisfactory
item, as compared to a control group of users interacting with a non-adaptive
version of the system
Matching Users' Preference Under Target Revenue Constraints in Optimal Data Recommendation Systems
This paper focuses on the problem of finding a particular data recommendation
strategy based on the user preferences and a system expected revenue. To this
end, we formulate this problem as an optimization by designing the
recommendation mechanism as close to the user behavior as possible with a
certain revenue constraint. In fact, the optimal recommendation distribution is
the one that is the closest to the utility distribution in the sense of
relative entropy and satisfies expected revenue. We show that the optimal
recommendation distribution follows the same form as the message importance
measure (MIM) if the target revenue is reasonable, i.e., neither too small nor
too large. Therefore, the optimal recommendation distribution can be regarded
as the normalized MIM, where the parameter, called importance coefficient,
presents the concern of the system and switches the attention of the system
over data sets with different occurring probability. By adjusting the
importance coefficient, our MIM based framework of data recommendation can then
be applied to system with various system requirements and data
distributions.Therefore,the obtained results illustrate the physical meaning of
MIM from the data recommendation perspective and validate the rationality of
MIM in one aspect.Comment: 36 pages, 6 figure
- …