The Complexity of Multiterminal Cuts
SIAM Journal on Computing
Approximation of k-set cover by semi-local optimization
STOC '97 Proceedings of the twenty-ninth annual ACM symposium on Theory of computing
Directed diffusion: a scalable and robust communication paradigm for sensor networks
MobiCom '00 Proceedings of the 6th annual international conference on Mobile computing and networking
Introduction to Linear Optimization
Introduction to Linear Optimization
Rumor routing algorthim for sensor networks
WSNA '02 Proceedings of the 1st ACM international workshop on Wireless sensor networks and applications
Offering a Precision-Performance Tradeoff for Aggregation Queries over Replicated Data
VLDB '00 Proceedings of the 26th International Conference on Very Large Data Bases
Data-centric storage in sensornets
ACM SIGCOMM Computer Communication Review
Faster and Simpler Algorithms for Multicommodity Flow and other Fractional Packing Problems.
FOCS '98 Proceedings of the 39th Annual Symposium on Foundations of Computer Science
The Cougar Project: a work-in-progress report
ACM SIGMOD Record
Data-centric routing and storage in sensor networks
Wireless sensor networks
Revisiting the TTL-based controlled flooding search: optimality and randomization
Proceedings of the 10th annual international conference on Mobile computing and networking
Maximum lifetime routing in wireless sensor networks
IEEE/ACM Transactions on Networking (TON)
Combs, needles, haystacks: balancing push and pull for discovery in large-scale sensor networks
SenSys '04 Proceedings of the 2nd international conference on Embedded networked sensor systems
TinyDB: an acquisitional query processing system for sensor networks
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2003
Operator placement for in-network stream query processing
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Distributed Cross-Layer Scheduling for In-Network Sensor Query Processing
PERCOM '06 Proceedings of the Fourth Annual IEEE International Conference on Pervasive Computing and Communications
CAPS: Energy-Efficient Processing of Continuous Aggregate Queries in Sensor Networks
PERCOM '06 Proceedings of the Fourth Annual IEEE International Conference on Pervasive Computing and Communications
Network-Aware Operator Placement for Stream-Processing Systems
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
Fundamental scaling laws for energy-efficient storage and querying in wireless sensor networks
Proceedings of the 7th ACM international symposium on Mobile ad hoc networking and computing
Energy and quality aware query processing in wireless sensor database systems
Information Sciences: an International Journal
Network-aware query processing for stream-based applications
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
Query Processing in Sensor Networks
IEEE Pervasive Computing
Adaptive and decentralized operator placement for in-network query processing
IPSN'03 Proceedings of the 2nd international conference on Information processing in sensor networks
Comparative analysis of push-pull query strategies for wireless sensor networks
DCOSS'06 Proceedings of the Second IEEE international conference on Distributed Computing in Sensor Systems
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Monitoring applications emerge as one of the most important applications of wireless sensor networks (WSNs). Such applications typically have long-running complex queries that are continuously evaluated over the sensor measurement streams. Due to the limited energy of the sensors in WSNs, energy efficient query evaluation is critical to prolong the system lifetime - the earliest time that the network can not perform its intended task anymore. We model complex queries by expression trees and consider the problem of maximizing the lifetime of a wireless sensor network for the continuous in-network evaluation of an expression trees T, so the value of its root is available at the base station. In-network evaluation means that the evaluation of the operators of T may be pushed to the network nodes, and continuous means the repeated evaluation of T (once at each round). Continuous in-network evaluation of T entails addressing the following two coupled aspects of the problem: (a) the placement of the operators, variables, and constants of T to network nodes and (b) the routing of their values to the appropriate network nodes that needed them to evaluate the operators. We analyze the complexity and provide a simple and effective algorithm for the placement of the nodes of T onto the sensor nodes of a WSN. Our algorithm of operator placement attempts to minimize the total amount of data that need to be communicated. A placement of T induces a certain Maximum Lifetime Concurrent Flow (mlcf) problem. We provide an efficient algorithm that finds near-optimal integral solutions to the mlcf problem, where a solution is a collection of paths on which certain amount of integral flow is routed. Our approach to the continuous in-network evaluation of T consists of utilizing both our placement and routing algorithms above. We demonstrate experimentally that our approach consistently and effectively find the maximum lifetime solutions for the continuous in-network evaluation of expression trees in wireless sensor networks.