Choon-Sung Nam

Cluster Head Selection for Equal Cluster Size in Wireless Sensor Networks

The goal of wireless sensor networks is to collect sensing data on a specific region using wireless communication. The sink node gathers all local sensing data, processes them, and transmits them to users who use sensor networks. Generally, sensor nodes are low-cost, low power devices with limited sensing, computation and wireless communication capabilities. A sensor network applies to multi-hop communication on a large-scale network. As neighboring sensor nodes have similar data, clustering is an effective technique for ‘data-aggregation’. In the multi-hop based cluster formation technique, it is necessary that the number of cluster member nodes should be distributed equally due to the balance of cluster formation. Therefore, this paper proposes a method of cluster head selection to form equal cluster sizes in wireless sensor networks

Sensor Network Middleware for Distributed and Heterogeneous Environments

Sensor networks consist of various sensors. Existing development of sensor networks is hard to federation and communication each other because they use different data format depend on their characteristics. Thereby, it needs to middleware that can merge raw data from heterogeneous sensor networks. For that reason, we propose sensor network middleware that able to translate sensed data from sensor networks using extended markup language(XML) and provide translated data for various web applications.

Extended Hierarchical Routing over 6LoWPAN

The feature of 6LoWPAN is the capability of the dynamic assignment of 16bit short addresses. By using this dynamically assigned short address, a hierarchical routing is employed. In case of node failure, this hierarchical routing does not support a technique for path recovery. So, this paper proposes the path recovery technique for hierarchical routing over 6LoWPAN.

BLE-OTP Authorization Mechanism for iBeacon Network Security

Machine to Machine (M2M) technology has gained attention due to the fast diffusion of Internet of Things (IoT) technologies and smart devices. Most wireless network experts believe that Bluetooth Low Energy (BLE) Communications technology in an iBeacon network has amazing advantages in terms of providing communication services at a low cost in smartphone applications. Specifically, BLE does not require any pairing process during its communication phases, so it is possible to send a message to any node without incurring additional transmissions costs if they are within the BLE communication range. However, BLE does not require any security verification during communication, so it has weak security. Therefore, a security authorization process would be necessary to obtain customer confidence. To provide security functions for iBeacon, we think that the iBeacon Message Encryption process and a Decryption (Authorization) process should be designed and implemented. We therefore propose the BLE message Authorization Mechanism based on a One Time Password Algorithm (BLE-OTP). The effectiveness of our mechanism is evaluated by conducting a performance test on an attendance system based on BLE-OTP.

A compariosn of open and closed mobile platforms

The market of smartphone is growing at a remarkable rate and is one of the important emerging issues. People who use the smartphone go on increasing in the world. There are a lot of applications for the smartphone and they are more complicated. Therefore, various mobile platforms have been improved to meet such conditions. In this paper we consider desirable characteristics of open and closed mobile platforms for research. Based on these characteristics, we deal with two smartphone platforms: Android and iPhone.

Efficient path setup and recovery in wireless sensor networks by using the routing table

Interest for wireless sensor networks has being increased in ubiquitous environment. In wireless sensor networks, each node sets up self-organization network, transfer the sensing data to sink node. Sensor nodes that compose sensor network are small size, and their battery capacity is limited. So, each node also imposes a constraint on search and recovery of data-path. In this paper, we designed a method to build data-path, considering restrictive features of a sensor node. Each node uses the routing table which consists of state information of a node and neighbors, to set up the data-path. Using the routing table, they can efficiently transfer the sensing data from each node to a sink.

Agent-based sensor network middleware using reputation mechanism over heterogeneous network environments

Sensor networks consist of various sensors and have a constraint depend on its physical characteristics. The sensor network middleware can provide with abstractions of characteristics about each sensor network to user applications. Thereby, these sensor networks can cooperate easily with traditional network through sensor network middleware platform. In this manner, agents in platform interact with each other but they have a problem such as lack of reliability. So, we propose the agent-based sensor network middleware using reputation mechanism over heterogeneous network environments to provide enhanced service discovery and agent management.

Strong Authentication and Key Agreement Protocol in UMTS

3GPP (3rd Generation Partnership Project) proposed UMTS AKA (Authentication and Key Agreement) protocol, authentication and key exchange protocol, for safety wireless communication in UMTS (Universal Mobile Telecommunications System), one of 3rd mobile communication technologies. UMTS AKA, however, has problems with network bandwidth consumption, storage space overhead, synchronization of SQN and so on. In this paper, we propose the ticket based T-AKA protocol that solves the problem of UMTS AKA. The proposed protocol can support privacy protection, mutual authentication and forward security.

Design of wireless sensor networks middleware using the publish/subscribe paradigm

WSNs middleware is software positioned between applications and the operating system in sensor nodes. This middleware should have a communication function between the sensor nodes, to support good interactive functions between the users applications. It must balance the resource use between the client and server system. WSNs comprise server-side middleware and in-network middleware. Server-side middleware supports application services efficiently in the server system. In-network middleware, located between sensor nodes, is in charge of managing the inner sensing information. We choose an event-driven network, the publish and subscribe network model, to support WSN. Using this model, sensor networks could reduce unnecessary energy consumption and respond to a variety of user requests.

Multihop-Based Optimal Cluster Heads Numbers Considering Relay Node in Transmission Range of Sensor Nodes in Wireless Sensor Networks

The data transmission of sensor nodes which detect events might be affected by their neighbor nodes located in their communication range. Thus, we analyze the energy consumption of sensor networks as a function of the number of cluster heads considering the above two options, multihop-based communication and the case where a neighbor node is in the transmission range for communicating data. This helps us to elect the number of energy-efficient cluster heads in a more practical manner. Also, we determine the effect of electing the number of cluster heads by restricting the local cluster size.