Hyun-Jong Cha

QoS routing mechanism using mobility prediction of node in ad-hoc network

MANET(Mobile Ad hoc NETwork) consists of movable only wireless nodes, except fixed station in the wired network. Not only hosts, but also routers for data packet forwarding in network topology changes. It is hard for routing algorithm using previous wired network to be applied to this ad hoc network. In the beginning, table-driven algorithm such as DSDV was shown in MANET, which resulted researches of On-demand routing protocols such as DSR, supporting mobility for mobile terminals. Recently, a routing protocol was developed, combined advantages of the former and the latter, called AODV(Ad hoc On-demand Distance Vector). However, despite advantages of AODV, it makes overall network performance weak due to nodes that move frequently, resulting considerable routing control traffic. In this paper, we propose efficient routing mechanism with route prediction of nodes for link reliability in MANET. Our work collects routes from source to destination with AOMDV. In this process, each node with GPS (Global Positioning System) predicts to move expected location by calculating nodes location and velocity. With this mechanism, it makes source node can decide the route which has the longest connection time. And due to the reason why the node can choose appropriate route to data property among multiple routes collected to AOMDV, it also can reduce unnecessary control messages in MANET. By NS2 simulation, we analyze the former routing protocols to demonstrate the superiority of our work.

A node management scheme for stable P2P service in mobile ad-hoc networks

In a mobile ad-hoc network, multiple number of nodes can communicate with one another without the need for an infrastructure network. It is used in many different types of places, including military zones and disaster or hazardous areas. In a mobile ad-hoc network, each node acts both as a main agent of communication and a relay. Furthermore, each gives a weakness to the network or is subjected to vulnerabilities from malicious attacks due to their distinctive qualities, namely mobility and limited power. Accordingly, in order for stable P2P service, it is important to maintain the reliability and connectivity of the network at a high level. With existing schemes, it has often been the case that when defective nodes or malicious nodes are detected, it also causes damage to normal nodes. In scheme suggested in this paper, those nodes that have temporary defects but otherwise normal and can recovered are kept in the network but those that are defective or malicious are eliminated from the network, using trust values. The simulation was carried out to evaluate the performance of the proposed method. As a result, the message transmission rate even if the impact of a malicious node than the conventional method was demonstrated increased keeping the stable network topology.

A Study on the Clustering Scheme for Node Mobility in Mobile Ad-hoc Network

A mobile ad-hoc network is an autonomous collection of wireless mobile nodes that organizes a temporary network without any network infrastructure. Due to node mobility, it is a challenging task to maintain the network topology. In this paper, we propose a stable clustering algorithm that uses node mobility for cluster formation. In the proposed algorithm, the node mobility is measured by counting the time of nodes entering into leaving from its transmission range. The node having the lowest mobility is selected as a cluster head. For topology maintenance with reduced control overhead, the cluster head adaptively controls the broadcasting period of hello message to the measured node mobility. Through computer simulations, it is verified that the proposed algorithm outperforms previous clustering algorithms in terms of control overhead, the rate of node mobility changes and the number of cluster head changes.

A Study on the Design of Fog Computing Architecture Using Sensor Networks

It is expected that the number of devices connecting to the Internet-of-Things (IoT) will increase geometrically in the future, with improvement of their functions. Such devices may create a huge amount of data to be processed in a limited time. Under the IoT environment, data management should play the role of an intermediate level between objects and devices that generate data and applications that access to the data for analysis and the provision of services. IoT interactively connects all communication devices and allows global access to the data generated by a device. Fog computing manages data and computation at the edge of the network near an end user and provides new types of applications and services, with low latency, high frequency bandwidth and geographical distribution. In this paper, we propose a fog computing architecture for efficiently and reliably delivering IoT data to the corresponding IoT applications while ensuring time sensitivity. Based on fog computing, the proposed architecture provides efficient power management in IoT device communication between sensors and secure management of data to be decrypted based on user attributes. The functional effectiveness and the safe data management of the method proposed are compared through experiments.

A Design of System using homomorphic encryption for multimedia data management

With the introduction of the concept of information warfare, the way military operations are done is changing quickly. Now, much more than it was in past, quick acquisition of information and effective decision making are crucial. Especially, these days the ratio of multimedia data is on the rise. A data management system has been put in place since the 1980s which encrypts information before storing it, and allowing only authorized users to gain access to it according to the proper procedures.In this paper, a secure and effective multimedia data management system that uses homomorphic operations is designed and implemented. By using homomorphic operations, it is able to quickly process stored ciphertext without a decryption process, allowing fast decision making after information gathering in a NCW environment. In order to assess the performance of the effective multimedia data management system implemented in this paper, it was compared to an ordinary system in which ciphertext has to be first decrypted before it can be modified. The secure and effective multimedia data management system for information warfare implemented in this study is highly versatile because any public encryption algorithm can be used, and has short response times thanks to the homomorphic algorithm which allows processing to be done directly on the ciphertext.

A study on mobile ad-hoc network for reliable multimedia streaming services

With innovative developments made in the research of wireless communication network technologies, many different types of cutting-edge wireless systems are being developed and used today. This paper focuses on the development of a MANET(Mobile Ad-hoc network) scheme intended to be used for delivery of wireless multimedia streaming services. MANET don’t use a fixed infrastructure network but mobile devices form the network themselves autonomously. But owing to un-stability in the state of the wireless channel formed in this way, there will be frequent transmission delays and data losses. In ordinary routing schemes available for data transmission, the greater the amount of data transmitted by the devices, the more severe the quality degradation. Therefore, these schemes are not suitable for streaming multimedia data. This paper suggests a stable protocol that takes into account mobility of nodes, in order to provide an efficient scheme for streaming video content in a MANET. The suggested protocol handles movements of nodes particularly well compared to the existing MP-AOMDV(Mobility Prediction Ad-hoc on-demand Multipath Distance Vector) scheme. The test results show the performance of the suggested protocol. In a large network, it has a short response time and a high transmission success rate. Use of the suggested protocol increases the reliability of the transmission paths, thereby resulting in more organic or flexible handling of changes to the network topology. Furthermore, multimedia streaming services can be delivered more stably compared to when existing systems or schemes are used.

mVoIP for P2P service based authentication system using AA authentication server

VoIP (Voice over Internet Protocol), which provides voice calls as well as additional services at cheaper prices than PSTN (Public Switched Telephone Network), is gaining ground over the latter, which had been the dominant telephone network in the past. This kind of a VoIP service is evolving into a dedicated mVoIP service for the smartphone which allows calls to be made at cheap prices using a WiFi network, as the number of smartphone users is skyrocketing as of late. While an increase in the user base is expected for mVoIP, a packet network is an open network which means anyone can easily gain access and so there can be various problems. To mitigate this, in this paper an authentication system is designed which has an AA (Attribute Authority) server added to VoIP in order to increase security and discriminate user access. In this paper a system for addressing security vulnerabilities from the increase in the use of VoIP services and providing differentiated services according to user access privileges is designed. This paper is organized as follows: Chapter 1 gives the introduction; Chapter 2 is on related research; Chapter 3 describes the proposed technique and system; Chapter 4 implements the system and analyzes its the performance; and Chapter 5 gives the conclusions.

A Study on Optimization for Acquisition and Processing of Massive Battlefield Information for Korean NCW

The future warfare will universalize the operation of a combined weapon system that utilizes this technology and create an operational environment that is centered on a network requiring a high level of interoperability between combat elements as well as a high level of operation speed. Therefore, the study attempts to draw out a Korean measurement plan concerning battlefield environment changes in the future by investigating and analyzing all problems occurring during the mass acquisition and processing of battlefield information in battlefield situations of network centric warfare currently conducted by the US military in Afghanistan and Iraq.

The design of reliable routing protocols in wireless mesh networks

Wireless Mesh Networks provide much flexibility in establishing a network compared to existing wire networks. A higher level of security is required for a wireless environment that makes the network accessible by anyone. Compared to MANET, Wireless Mesh Networks is less portable, and have less sensitivity to electric power. This enables the adoption of a higher level of security. This study takes advantage of the PKI (Public Key Infrastructure) security algorithm to optimize a Wireless Mesh Network, so that it is applicable to a Wireless Mesh Network environment. A Pre-Shared Key, which is dynamically created and utilizes the hash function, is adopted as the routing authentication method of the mesh router and for the distribution of Keys necessary for data encryption. Each router node of a Wireless Mesh Network encrypts a random number data for electronic signature. The techniques for supervision, detection and avoidance of malicious nodes between router nodes on a Wireless Mesh Network are presented. The security technique is applied in this environment.

A Study of Information Protection Development Direction in Network Center Environment

According as Information Technology develops, in conventional type war that aspect of war depends on Performance of individuation inorganic substance network by NCW (Network Centric Warfare) that consist of cooperation form worming between each inorganic substance to base change. NCW has patience tactics for successful, effective tactics self-discipline and do improvement of military strength through connection between constituents by purpose guaranteeing share of information utilizing data processing ability of computer and ability of technology of communications that is linked to network. This War about Network Centric tactics that is NCW key concept. So, we wish to examine, and present about information protection development direction hereafter through requirement to keep information protection about information protection threat in network center tactics environment that is based on network in this paper.