Query-issuing Node Research Articles

An Efficient Identification of Malicious Node in Top-k Query Processing

In mobile ad hoc networks (MANETs), data items can be retrieved effectively by using top-k query processing method. The environment which contains malicious nodes cannot provide an accurate result. This paper assumes that the malicious node tries to attempt an attack called data replacement attack in which the necessary data sets are replaced by unnecessary data sets. The proposed work includes node grouping method in top-k query processing for detecting the malicious node. The accuracy of the query result can be maintained by forwarding the data sets along multiple routes and based on the information attached to the reply message the query-issuing node can detect the attack. By exchanging the message, single malicious node can be identified. To identify multiple malicious nodes, it’s necessary to share the information of identified malicious node to other nodes. In this method, nodes are grouped based on the similarity of the identified malicious node. Simulation experiments are conducted by using a network simulator, NS2, to verify that this method provides high accuracy and identifies multiple malicious nodes.

Top-k Query Processing and Malicious Node Identification Based on Node Grouping in MANETs

In mobile ad hoc networks (MANETs), it is effective to retrieve data items using top-k query. However, accurate results may not be acquired in environments when malicious nodes are present. In this paper, we assume that malicious nodes attempt to replace necessary data items with unnecessary ones (we call these data replacement attacks), and propose methods for top-k query processing and malicious node identification based on node grouping in MANETs. In order to maintain the accuracy of the query result, nodes reply with k data items with the highest score along multiple routes, and the query-issuing node tries to detect attacks from the information attached to the reply messages. After detecting attacks, the query-issuing node tries to identify the malicious nodes through message exchanges with other nodes. When multiple malicious nodes are present, the query-issuing node may not be able to identify all malicious nodes at a single query. It is effective for a node to share information about the identified malicious nodes with other nodes. In our method, each node divides all nodes into groups by using the similarity of the information about the identified malicious nodes. Then, it identifies malicious nodes based on the information on the groups. We conduct simulation experiments by using a network simulator, QualNet5.2, to verify that our method achieves high accuracy of the query result and identifies malicious nodes.

<inline-formula> <tex-math notation="LaTeX">\(K\) </tex-math></inline-formula> NN Query Processing Methods in Mobile Ad Hoc Networks

In this paper, we propose two beacon-less kNN query processing methods for reducing traffic and maintaining high accuracy of the query result in mobile ad hoc networks (MANETs). In these methods, the query-issuing node first forwards a kNN query using geo-routing to the nearest node from the point specified by the query (query point). Then, the nearest node from the query point forwards the query to other nodes close to the query point, and each node receiving the query replies with the information on itself. In this process, we adopt two different approaches: the Explosion (EXP) method and the Spiral (SPI) method. In the EXP method, the nearest node from the query point floods the query to nodes within a specific circular region, and each node receiving the query replies with information on itself. In the SPI method, the nearest node from the query point forwards the query to other nodes in a spiral manner, and the node that collects a satisfactory kNN result transmits the result to the query-issuing node. Experimental results show that our proposed methods reduce traffic and achieve high accuracy of the query result, in comparison with existing methods.

Top-k query processing for replicated data in mobile peer to peer networks

In mobile ad hoc peer to peer (M-P2P) networks, since nodes are highly resource constrained, it is effective to retrieve data items using a top-k query, in which data items are ordered by the score of a particular attribute and the query-issuing node acquires data items with the k highest scores. However, when network partitioning occurs, the query-issuing node cannot connect to some nodes having data items included in the top-k query result, and thus, the accuracy of the query result decreases. To solve this problem, data replication is a promising approach. However, if each node sends back its own data items (replicas) responding to a query without considering replicas held by others, same data items are sent back to the query-issuing node more than once through long paths, which results in increase of traffic. In this paper, we propose a top-k query processing method considering data replication in M-P2P networks. This method suppresses duplicate transmissions of same data items through long paths. Moreover, an intermediate node stops transmitting a query message on-demand.