1,864 research outputs found
A network-aware framework for energy-efficient data acquisition in wireless sensor networks
Wireless sensor networks enable users to monitor the physical world at an extremely high fidelity. In order to collect the data generated by these tiny-scale devices, the data management community has proposed the utilization of declarative data-acquisition frameworks. While these frameworks have facilitated the energy-efficient retrieval of data from the physical environment, they were agnostic of the underlying network topology and also did not support advanced query processing semantics. In this paper we present KSpot+, a distributed network-aware framework that optimizes network efficiency by combining three components: (i) the tree balancing module, which balances the workload of each sensor node by constructing efficient network topologies; (ii) the workload balancing module, which minimizes data reception inefficiencies by synchronizing the sensor network activity intervals; and (iii) the query processing module, which supports advanced query processing semantics. In order to validate the efficiency of our approach, we have developed a prototype implementation of KSpot+ in nesC and JAVA. In our experimental evaluation, we thoroughly assess the performance of KSpot+ using real datasets and show that KSpot+ provides significant energy reductions under a variety of conditions, thus significantly prolonging the longevity of a WSN
Mint views: Materialized in-network top-k views in sensor networks
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 between V and the underlying and distributed base relation R is very expensive in terms of communication. Thus, our approach focuses on a subset V(sube. V) that unveils only the k highest-ranked answers at the sink for some user defined parameter k. We additionally provide an elaborate description of energy-conscious algorithms for constructing, pruning and maintaining such recursively- defined in-network views. Our trace-driven experimentation with real datasets show that MINT offers significant energy reductions compared to other predominant data acquisition models
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Recording Victim Video Statements as Evidence to Advance Legal Outcomes in Family Violence Cases (ReVEAL)
This Implementation Guide provides an overview of the video-recording practices currently in place across several Texas jurisdictions. It provides guidance and considerations for jurisdictions in the collection and use of video evidence in family violence cases. This guide is divided into seven sections, including this Background and Overview. The second section includes information for law enforcement on the purpose of video statements, how to develop and implement a video program, and considerations for sustaining a program. The third section focuses on prosecutorial practices for the use of video statements including legal considerations, coordination with partners, and victim engagement around the video statement. The fourth section provides specific information for victim advocates and includes considerations for victim privacy and confidentiality. The fifth section focuses on technology and equipment, with information on type of equipment, technology infrastructure, and efficient transfer of evidence between agencies. The sixth section is the Summary Report of the ReVEAL project. The Summary Report is a technical overview of the evaluation that includes major findings and links to the ReVEAL reports that were previously released. The seventh and final section is comprised of the appendices and provides sample protocols, site overviews, equipment charts, and additional resources that may be helpful to users of this guide. Throughout this guide, there are several examples of cases and practices that illustrate the specific issues that may present themselves when launching a video-recording program. These
examples highlight the complexities of the practice while using real world examples of how video impacts family violence cases,
victim safety, and privacy.IC2 Institut
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