A filtering technique for n-way stream joins in wireless sensors networks

Purpose ”“ The join operations between data streams need more time and request more energy than traditional joins. In wireless sensor networks, energy is a critical factor. The survival of the network depends on this energy, thus it is necessary to consider, for this type of queries in such networks, the reduction of the sensors’ energy consumption. While works that have been done to treat n-way join operations between data streams are rare so far, we propose a technique, named NSLSJ (N-way Stream Local Semi-Join) to perform this type of join operations. The principal aim is to considerably reduce the consumed energy. Methodology/approach/design ”“ The technique 'N-way Stream Local Semi-Join (NSLSJ) proposed in this paper is based on an in-network execution, and on filtering tuples strategy for an important gain in energy. Findings ”“ Compared to NSLJ and Sens-Join techniques, NSLSJ shows better performances in the realized tests as it consumes less energy.Purpose ”“ The join operations between data streams need more time and request more energy than traditional joins. In wireless sensor networks, energy is a critical factor. The survival of the network depends on this energy, thus it is necessary to consider, for this type of queries in such networks, the reduction of the sensors’ energy consumption. While works that have been done to treat n-way join operations between data streams are rare so far, we propose a technique, named NSLSJ (N-way Stream Local Semi-Join) to perform this type of join operations. The principal aim is to considerably reduce the consumed energy. Methodology/approach/design ”“ The technique 'N-way Stream Local Semi-Join (NSLSJ) proposed in this paper is based on an in-network execution, and on filtering tuples strategy for an important gain in energy. Findings ”“ Compared to NSLJ and Sens-Join techniques, NSLSJ shows better performances in the realized tests as it consumes less energy.Purpose ”“ The join operations between data streams need more time and request more energy than traditional joins. In wireless sensor networks, energy is a critical factor. The survival of the network depends on this energy, thus it is necessary to consider, for this type of queries in such networks, the reduction of the sensors’ energy consumption. While works that have been done to treat n-way join operations between data streams are rare so far, we propose a technique, named NSLSJ (N-way Stream Local Semi-Join) to perform this type of join operations. The principal aim is to considerably reduce the consumed energy. Methodology/approach/design ”“ The technique 'N-way Stream Local Semi-Join (NSLSJ) proposed in this paper is based on an in-network execution, and on filtering tuples strategy for an important gain in energy. Findings ”“ Compared to NSLJ and Sens-Join techniques, NSLSJ shows better performances in the realized tests as it consumes less energy

An energy-efficiency technique for n-way stream joins in wireless sensor networks

In wireless sensor networks, the critical factor is the sensors energy. The exhaustion of this energy causes network paralysis. In wireless sensor networks, the join operation needs a lot of energy consumption. This energy is so very high for nway join queries, and more very high for nway stream queries. Little work has been done to address this problem. We present in this paper, an energy-efficiency technique for n-way joins execution between data streams in wireless sensor networks. The experiment conducted has shown good performance of the proposed technique compared to SENS-join technique

A Comparative Evaluation of Techniques for N-Way Joins in Wireless Sensors Networks

In wireless sensors networks, data are sensed and recorded as databases, and then acceded by relational queries. Joins are queries that are largely used. Joins collect data from several nodes’ table. These are operations that typically consume a lot of energy because they generate a large number of messages in the network. Researchers worked to decrease this consumed energy. Many strategies were proposed in this way, but most of them addressed only binary joins. N-way joins received few interests. N-way joins perform join operations between more than two tables. They cause greater energy consumption. Additionally, the number of execution order is very important; it grows exponentially with the number of considered tables. In this paper, a comparative study is performed between existing techniques for processing N-way joins in wireless sensor networks. These are two recent techniques: N-way Local Join and N-way Local Semi-Join, and two reference techniques, Sens-join and extern join. Several convenient parameters are selected to make this comparison. For each strategy, the ideal cases of its use are determined

A technique for n-way joins in wireless sensor networks

The join queries are operations that require more energy for their execution. In wireless sensor networks, energy is a determinant factor for the network survival. However, high energy consumption caused by such requests needs the implementation of very appropriate techniques for their execution. Research in this field considered especially binary joins. Few studies have addressed n-way joins. In this paper, we propose 'Nway Local Join', an energy-efficient technique for n-way join operations. We adopt an in-network execution at each step of the join operation. We compare our solution with an execution at the sink. NLJ shows the best performance for low selectivity factor