Young-Ju Han

CHEF: Cluster Head Election mechanism using Fuzzy logic in Wireless Sensor Networks

In designing the wireless sensor networks, the energy is the most important consideration because the lifetime of the sensor node is limited by the battery of it. To overcome this demerit many research have been done. The clustering is the one of the representative approaches. In the clustering, the cluster heads gather data from nodes, aggregate it and send the information to the base station. In this way, the sensor nodes can reduce communication overheads that may be generated if each sensor node reports sensed data to the base station independently. LEACH is one of the most famous clustering mechanisms. It elects a cluster head based on probability model. This approach may reduce the network lifetime because LEACH does not consider the distribution of sensor nodes and the energy remains of each node. However, using the location and the energy information in the clustering can generate big overheads. In this paper we introduce CHEF - cluster head election mechanism using fuzzy logic. By using fuzzy logic, collecting and calculating overheads can be reduced and finally the lifetime of the sensor networks can be prolonged. To prove efficiency of CHEF, we simulated CHEF compared with LEACH using the matlab. Our simulation results show that CHEF is about 22.7% more efficient than LEACH.

The Concentric Clustering Scheme for Efficient Energy Consumption in the PEGASIS

The wireless sensor network is a type of the wireless ad-hoc networks. It is composed of a collection of sensor nodes. Sensor nodes collect and deliver necessary data in response to users specific requests. It is expected to apply the wireless sensor network technology to various application areas such as the health, military and home. However, because of several limitations of sensor nodes, the routing protocols used in the wireless ad-hoc network are not suitable for the wireless sensor networks. For this reasons, many novel routing protocols for the wireless sensor networks are proposed recently. One of these protocols, the PEGASIS (power-efficient gathering in sensor information systems) protocol is a chain-based protocol. In general, the PEGASIS protocol presents twice or more performance in comparison with the LEACH (low energy adaptive clustering hierarchy) protocol. However, the PEGASIS protocol causes the redundant data transmission since one of nodes on the chain is selected as the head node regardless of the base stations location. In this paper, we propose the enhanced PEGASIS protocol based on the concentric clustering scheme to solve this problem. The main idea of the concentric clustering scheme is to consider the location of the base station to enhance its performance and to prolong the lifetime of the wireless sensor networks. As simulation results, the enhanced PEGASIS protocol using the concentric clustering scheme performs better than the current PEGASIS protocol by about 35%.

Context-Role based access control for context-aware application

The rapid growth of wireless network technology and the deployment of mobile computing devices have enabled the construction of pervasive computing environment. In pervasive computing environment, it is proliferated that many new applications that provide active and intelligent services by context information are collected by pervasive sensor devices. These new applications called context-aware applications must require new security mechanisms and policies different from typical ones. Specially, access control mechanism supports security policy that is based on context information, in order to provide automating context-aware services. So, this paper analyzes various access control mechanisms and proposes a context-role based access control mechanism for context-aware application.

Active Cyber Attack Model for Network System's Vulnerability Assessment

In this paper, we architected active cyber attack model for assessing network systems vulnerability. As simulating cyber attack model in network system, we can identify the weakest point and inspect security policy. It also improved the capability of information collection and attack action, as using autonomous agents. Attack action agents which introduced attack a set of sequence number can reduce transmission overhead and hide attack scenarios information. We built attack scenario for attack process and technique of attack action agents. It is composed of attack pattern and tree. Action controller uses nodes attack success percent(ASP) to choose the second best attack scenario after the first attack was failed. ASP is calculated with the ratio of all achieved events until the sub-node over all nodes of the attack tree.

Risk Assessment Method Based on Business Process-Oriented Asset Evaluation for Information System Security

We presented risk assessment methodology focused on business-process oriented asset evaluation and qualitative risk analysis method. The business process-oriented asset evaluation is to evaluate assets value by the degree of asset contribution related to business process. Namely, assets value is different according to the importance of department to which asset belongs, the contribution of assets business, and security safeguard, etc. We proposed new assets value evaluation applied to the weight of above factors. The weight is decided by evaluation matrix by Delphi team. We assess risk by qualitative method applied to the improved international standard method which is added the effectiveness of operating safeguard at information system. It reflects an assumption that they can reduce risk level when existent safeguards are established appropriately. Our model derives to practical risk assessment method than existent risk assessment method, and improves reliability of risk analysis.

An Energy Efficient Concentric Clustering Scheme in Wireless Sensor Networks

In wireless sensor networks, sensor nodes have limited power so the lifetime of the networks is very important design factor. The chain-based routing scheme is one of the famous routing schemes that are proposed for reducing energy dissipation of communication in the networks. The chain-based routing schemes construct the chains for routing path. The chain-based routing schemes can reduce energy dissipation of transmitting data to base station by using the concept of multi-hop routing. PEGASIS, concentric-clustering routing scheme, and extended concentric-clustering routing scheme belong to the chain-based routing schemes. PEGASIS and concentric-clustering routing scheme do not balance energy dissipation among the sensor nodes. Especially the extended concentric-clustering routing scheme can distribute energy dissipation among each cluster. The extended concentric-clustering routing scheme fixes the number of sensor nodes in each cluster for balancing of energy dissipation among each cluster. Therefore the extended concentric-clustering routing scheme is able to make lifetime of the networks longer than the other chain-based routing schemes. However the extended concentric-clustering routing scheme still has limitation. This scheme cannot distribute energy dissipation. This difference is occurred by difference among transmitting data size of each cluster head. Because of this difference, energy dissipations are unbalanced and lifetime of the sensor networks is reduced. To overcome these problems, we propose an energy efficient concentric-clustering scheme. In our scheme, the number of sensor nodes is differently deployed to balance energy dissipation. As the simulation results, our scheme can distribute energy dissipation among the whole networks better than the extended concentric-clustering routing scheme.

SecDEACH: secure and resilient dynamic clustering protocol preserving data privacy in WSNs

Clustering scheme enabling the efficient utilization of the limited energy resources of the deployed sensor nodes can effectively prolong lifetime of wireless sensor networks. Like most of the protocols for wireless sensor networks, a clustering scheme is vulnerable to a number of security attacks. Especially, attacks involving cluster-heads are the most damaging since cluster-based schemes rely on their cluster-heads for routing and data aggregation. Several studies have proposed a secure clustering scheme and a resilient cluster leader election protocol in wireless sensor networks. However, most of resilient clustering schemes do not support dynamic clustering and most of secure clustering schemes are not robust and resilient against node(specially, cluster-heads) capture. In this paper, we present a secure and resilient clustering protocol on the basis of dynamic clustering protocol. Our scheme provides both a secure clustering and a resilient cluster-head election preserving dynamic clustering unlike the existing secure clustering schemes. In addition, our scheme provides data privacy through the concealed data aggregation. The analysis shows that our scheme offers the security services against both an inside attack and an outside attack while having the little memory, computation and communication overheads. The comparison with related works shows that our scheme has a great improvement in security and the reduction of the overheads compared to the existing schemes.

Architecture of context-aware integrated security management systems for smart home environment

The smart home technology is a noticeable area of study in various studies on the ubiquitous computing technology. This paper presents the security management system to provide context-aware security service. The system supports the management and enforcement of context-aware security and the management of the context of users and resources. This system provides the security service functions such as the partial credential based user authentication and context-aware access control, and the security policy management functions. In addition, the system provides the policy enforcement simulation function to test and validate the security policy. This simulator can cover all security service in the smart home environment.

Energy-efficient distance based clustering routing scheme for wireless sensor networks

Clustering scheme enabling the efficient utilization of the limited energy resources of the deployed sensor nodes can effectively prolong the lifetime of wireless sensor networks. The most common technique in famous clustering schemes is a probabilistic clustering scheme based on a randomized cluster-head rotation for distributing the energy consumption among nodes in each cluster. Because most of those schemes utilize mainly the residual energy of each node as the criterion of cluster-head election, those schemes have demerit which the unbalanced energy consumption among cluster-heads is occurred. To overcome this demerit, we consider a distance from the base station to cluster-heads as well as the residual energy as the criterion of cluster-head election for balanced energy consumption among cluster-heads. Our scheme provides fully distributed manner by utilizing local information and good energy-efficiency by load balanced clustering scheme. Through simulation experiments, we showed that the proposed scheme is more effective than LEACH and EECS in prolonging the lifespan of wireless sensor networks.

New binding update method using GDMHA in hierarchical mobile IPv6

Mobile IPv6 is a protocol that guarantees mobility of mobile node within the IPv6 environment. However current Mobile IPv6 supports simple the mobility of the mobile nodes and does not offer any special mechanism to reduce the handoff delay. For the purpose of reducing the handoff delay, Hierarchical Mobile IPv6 has been studied. However Hierarchical Mobile IPv6 supports the micro mobility only in the area managed by mobility anchor point. Therefore, the handoff delay problem still has been unsolved when mobile node moves to another mobility anchor point. In this paper, we propose GDMHA (Geographically Distributed Multiple HAs) mechanism to provide macro mobility between the mobility anchor points. Using this mechanism, a mobile node performs Binding Update with the nearest Home Agent, so that the delay of Binding Update process can be reduced. It also reduces the handoff delay.