ACM Transactions on Information Systems

Social media provides valuable resources to analyze user behaviors and capture user preferences. This article focuses on analyzing user behaviors in social media systems and designing a latent class statistical mixture model, named temporal context-...

We design algorithms that, given a collection of documents and a distribution over user queries, return a small subset of the document collection in such a way that we can efficiently provide high-quality answers to user queries using only the selected ...

We present in this article an external memory algorithm, called disk SA-IS (DSA-IS), to exactly emulate the induced sorting algorithm SA-IS previously proposed for sorting suffixes in RAM. DSA-IS is a new disk-friendly method for sequentially retrieving ...

Hierarchies serve as browsing tools to access information in document collections. This article explores techniques to derive browsing hierarchies that can be used as an information map for task-based search. It proposes a novel minimum-evolution ...

An online community consists of a group of users who share a common interest, background, or experience, and their collective goal is to contribute toward the welfare of the community members. Several websites allow their users to create and manage ...

Compression algorithms are important for data-oriented tasks, especially in the era of “Big Data.” Modern processors equipped with powerful SIMD instruction sets provide us with an opportunity for achieving better compression performance. Previous ...