Alexandros Labrinidis

Learn More
This paper presents TiNA, a scheme for minimizing energy consumption in sensor networks by exploiting end-user tolerance to temporal coherency. TiNA utilizes temporal coherency tolerances to both reduce the amount of information transmitted by individual nodes (communication cost dominates power usage in sensor networks), and to improve quality of data when(More)
In-network aggregation has been proposed as one method for reducing energy consumption in sensor networks. In this paper, we explore two ideas related to further reducing energy consumption in the context of in-network aggregation. The first is by influencing the construction of the routing trees for sensor networks with the goal of reducing the size of(More)
Dynamically generated web pages are ubiquitous today but their high demand for resources creates a huge scalability problem at the servers. Traditional web caching is not able to solve this problem since it cannot provide any guarantees as to the freshness of the cached data. A robust solution to the problem is web materialization, where pages are cached at(More)
Typical Web-database systems receive read-only queries, that generate dynamic Web pages as a response, and write-only updates, that keep information up-to-date. Users expect short response times and low staleness. However, it may be extremely hard to apply all updates on time, i.e., keep zero staleness, and also get fast response times, especially in(More)
Personalization, advertising, and the sheer volume of online data generate a staggering amount of dynamic Web content. In addition to Web caching, view materialization has been shown to accelerate the generation of dynamic Web content. View materialization is an attractive solution as it decouples the serving of access requests from the handling of updates.(More)
Dynamic content generation poses huge resource demands on web servers, creating a scalability problem. WebView Materialization, where web pages are cached and constantly refreshed in the background, has been shown to ameliorate the scalability problem without sacrificing data freshness. In this work we present an adaptive online algorithm to select which(More)
A <i>WebView</i> is a web page automatically created from base data typically stored in a DBMS. Given the multi-tiered architecture behind database-backed web servers, we have the option of materializing a WebView inside the DBMS, at the web server, or not at all, always computing it on the fly (virtual). Since WebViews must be up to date, materialized(More)
In-network aggregation has been proposed as one method for reducing energy consumption in networked sensors. In this paper, we explore the idea of influencing the construction of the routing trees for sensor networks with the goal of reducing the size of transmitted data for networks with in-network aggregation involving Group By queries. Toward this, we(More)
Association Rule Mining algorithms operate on a data matrix (e.g., customers $\times$ products) to derive association rules [AIS93b, SA96]. We propose a new paradigm, namely, Ratio Rules, which are quantifiable in that we can measure the “goodness” of a set of discovered rules. We also propose the “guessing error” as a measure of the “goodness”, that is,(More)