Panayiotis Andreou

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Continuous queries in wireless sensor networks are established on the premise of a routing tree that provides each sensor with a path over which answers can be transmitted to the query processor. We found that these structures are sub-optimality constructed in predominant data acquisition systems leading to an enormous waste of energy. In this paper we(More)
—In this paper we introduce MINT (Materialized In-Network Top-k) Views, a novel framework for optimizing the execution of continuous monitoring queries in sensor networks. A typical materialized view V maintains the complete results of a query Q in order to minimize the cost of future query executions. In a sensor network context, maintaining consistency(More)
—In this paper we present MicroPulse, a novel framework for adapting the waking window of a sensing device S based on the data workload incurred by a query Q. Assuming a typical tree-based aggregation scenario, the waking window is defined as the time interval τ during which S enables its transceiver in order to collect the results from its children.(More)
This paper assumes a set of <i>n</i> mobile sensors that move in the Euclidean plane as a swarm. Our objectives are to explore a given geographic region by detecting and aggregating spatio-temporal events of interest and to store these events in the network until the user requests them. Such a setting finds applications in environments where the user (i.e.,(More)
In order to process continuous queries over Wireless Sensor Networks (WSNs), sensors are typically organized in a Query Routing Tree (denoted as T) that provides each sensor with a path over which query results can be transmitted to the querying node. We found that current methods deployed in predominant data acquisition systems construct T in a sub-optimal(More)
— This demo presents a graphical user interface and ranking system, coined KSpot, for effectively monitoring the K highest-ranked answers to a query Q in a Wireless Sensor Network. KSpot deploys state-of-the-art distributed Top-k query processing algorithms in order to realize both snapshot queries and historic queries minimizing the consumption of system(More)
The explosive number of smartphones with ever growing sensing and computing capabilities have brought a paradigm shift to many traditional domains of the computing field. Re-programming smartphones and instrumenting them for application testing and data gathering at scale is currently a tedious and time-consuming process that poses significant logistical(More)
In long-term deployments of Wireless Sensor Networks, it is often more efficient to store sensor readings locally at each device and transmit those readings to the user only when requested (i.e., in response to a user query). Many of the techniques that collect information from a sensor network require that the data is sorted on some attribute (e.g., range(More)
This paper presents an e-health mobile application, called DITIS, which supports networked collaboration for home healthcare. The system was originally developed with a view to address the difficulties of continuity of care and communication between the members of a home health care multidisciplinary team. The paper introduces the system DITIS, identifies(More)