07-06-2013, 12:20 PM
Privacy Preservation by Anonymization and Location Monitoring System for WSN
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ABSTRACT
Mobile devices are becoming the largest sensor network around the world. They could be used to collect a large amount of data with little effort and cost which is leading to a promising future for sensing networks or urban sensing. Privacy of such mobile users in any areas is very important and critical issue. If Hacker tracks the position of mobile user he can easily access user’s personal information and misuse it. To avoid such misuse of confidential data, our system provides privacy through anonymization concept. Anonymization helps user to hide amongst no of users. With the help of anonymization concept we report aggregate location of any user instead of revealing its exact location .Aggregate location monitoring has a simple form of “What is the number of objects in a certain area”. Instead of providing exact location of user our system reports group of locations So that an attacker will not be able to track the exact location of user. Along with privacy preservation user’s location can also be monitored by our system. Location monitoring is the process of a continuously receiving position that identifies the location for a device or person.
INTRODUCTION
Wireless sensor network is consists of spatially distributed autonomous sensors to monitor physical or environmental conditions to cooperatively pass their data through the network to a main location in WSN, each user is considered as a node in a network and users are connected through links which are represented as edges on the network. There are two types of sensors in wireless sensor network: 1.Counting Sensors: These sensors report the count of persons located in their network to a server. 2. Identity Sensors: These type of sensors help system to pinpoint exact location of each monitored person.
ALGORITHMS
To implement our system two algorithms are used: 4.1 Resource aware algorithm Basic idea of this algorithm is to find adequate number of persons in that network and accordingly finding a cloaked area which further referred as MBR(minimum bounded area).there are two steps in this algorithm :
Broadcast step:
In this step, Every sensor node in a network broadcasts a message to nearer sensor nodes.in this message it passes its id,its sensor area and count of objects in its sensing area.In this way every sensor node forms its own peerlist.also every sensor node checks for adequate number of objects in its sensing area and accordingly it sends notification message to the nearer sensor nodes and follows the next step.
Search space step:
Since a typical sensor network has a large number of sensor nodes, it is too costly for a sensor node m to gather the information of all the sensor nodes to compute its minimal cloaked area. To reduce communication and computational cost,m determines a search space, S, based on the input cloaked area computed by the resource-aware algorithm, such that the sensor nodes outside S cannot be part of the minimal cloaked area. 4.2.2 The Minimal Cloaked Area step: This step takes a set of peers residing in the search space, S, as an input and computes the minimal cloaked area for the sensor node m.In this step we propose two optimization techniques to reduce computational cost. The basic idea of the first optimization technique is that we do not need to examine all the combinations of the peers in S; instead, we only need to consider the combinations of at most four peers. Because atmost two sensor nodes defines width of MBR and at most two sensor nodes defines height of MBR. Thus this optimization mainly reduces computational cost by reducing the number of MBR computations among the peers in S. The second optimization technique has two properties, lattice structure and monotonicity property. In a lattice structure, a data set that contains n items can generate 2n-1 item sets excluding a null set. We generate the lattice structure from the lowest level based on a simple generation rule. The monotonicity property of a function f indicates that if X is a subset of Y , then f(X) must not exceed f(Y). For our problem, the MBR of a set of sensor nodes S has the monotonicity property,because adding sensor nodes to S must not decrease the area of the MBR of S or the number of objects within the MBR of S.
CONCLUSION
In our paper we proposed a model for privacy preservation of mobile users with the help of anonymization and aggregate location monitoring concept in a wireless sensor network.Two location anonymization algoritms namely resource-aware and quality-aware algoritms are designed to preserve personal location and provide location monitoring services.Sensor nodes execute location anonymization algorithms to provide k-anonymous aggregate locations.