• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3623-3627
• /
• 2012

The modern society has become full-fledged entry into the information age since spread of Internet. In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4GHz band which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 5GHz band came to be interested. In this paper, we studied the design and fabrication of u-slot microstrip patch antenna to be used in wireless communication systems operating at around 5GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, u-slot microstrip patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.1
• /
• pp.120-130
• /
• 2009

In recent years, many mobile wireless communication devices and applications have been deployed on the planet. The mobile multi-hop wireless network models appeared to provide means to access to networks where few infrastructure exists. However, the mobile multi-hop wireless networks have weaker points in attacks and intrusions than the wired and one-hop wireless networks. In this paper, the secure routing issues in most mobile multi-hop wireless network models are surveyed in depth. The state-of-the-art technologies and research activities are explained. Finally, the issues and technologies for the secure routing specific to a maritime network model are sufficiently discussed as conclusions.

• International Journal of Contents
• /
• v.6 no.3
• /
• pp.59-64
• /
• 2010

The world mobile service is growing sharply and became bigger market than wired. So it is very needed to find the political way to promote mobile industry. The United States government recently decided to introduce new mobile policies for promoting mobile industry. Until now the telecommunications policies of the United States have affected policy developments for many countries including Korea. In this context, we studied the validity of introducing new mobile policies of the United States in Korea. We found that new mobile policies can cause the change of mobile market environment; mobile market power will be dispersed from network to content, application and devise, and new mobile market environment where consumers freely select and use network as well as content, application and devise will be made. Also we found empirically that if new policies are introduced in Korea, mobile industry will be promoted as Korean consumers use mobile services and goods quite actively in new mobile market. We think our results provide reasonable evidence to introduce new mobile policies in Korea.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.8
• /
• pp.22-33
• /
• 2009

Mobile Ad Hoc Networks (MANETs) are self-organized networks that do not rely in their operation on wired infrastructure. As in any networking technology, security is an essential element in MANET as well, for proliferation of this type of networks. But supporting secure communication in MANETs proved to be a significant challenge, mainly due to the fact that the set of nodes in the network can change frequently and rapidly and due to the lack of access to the wired infrastructure. In particular, the trust model and the authentication protocols, which were developed for wired and infrastructure-based networks, cannot be used in MANETs. In [1], we addressed the problem of efficient authentication of distributed mobile users in geographically large networks and proposed a new authentication scheme for this case of MANETs. The proposed scheme exploits randomized groups to efficiently share authentication information among nodes that together implement the function of a distributive Certification Authority(CA). In this paper, we analyze numerically the performance of authentication method using randomized groups and compare with the simulation result.

• Journal of Communications and Networks
• /
• v.7 no.2
• /
• pp.222-230
• /
• 2005

This article presents a field evaluation of an IP-based architecture for heterogeneous environments that has been developed under the aegis of the Moby Dick project, covering UMTS-like (universal mobile telecommunications system) TD-CDMA (time division-code division multiple access) wireless access technology, wireless and wired LANs. The architecture treats all transmission capabilities as basic physical and data-link layers, and replaces all higher-level tasks by IP-based strategies. The Moby Dick architecture incorporates mobile IPv6, fast handovers, AAA-control (authentication, authorisation, accounting), charging and quality of service (QoS) in an integrated framework. The architecture further allows for optimised control on the radio link layer resources. It has been implemented and tested by expert users, and evaluated by real users on field trials with multiple services available.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.2 no.3
• /
• pp.325-333
• /
• 1998

In this paper, conventional STM(Synchronous Transfer Mode) supports another traffics by using idle channels. Proposed mobile terminals are distributed independently at the BSA(Basic Service Area). So, MAC(Medium Access Control) specified on the wireless ATM networks, which is managing statistics multiplewing functions, idle channel's ultilization is maximized and multimedia service characteristic for conventional wired networks based fixed assignment scheme(connection-oriented) and random assignment scheme(connection-oriented) improving on dynamic reservation based MAC protocol.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1998.05a
• /
• pp.132-137
• /
• 1998

In this paper, conventional STM(Synchronous Transfer Mode) supports another traffics by using idle channels Proposed mobile terminals are distributed independently at the BSA(Basic Service Area). So, MAC(Medium Access Control) specified on the wireless ATM networks, which is managing statistics multiplexing functions, idle channel's utilization is maximized and multimedia service characteristic for conventional wired networks based fixed assignment scheme(connection-oriented) and random assignment scheme(connectionless) improving on dynamic reservation based MAC protocol.

• International Journal of Advanced Culture Technology
• /
• v.10 no.2
• /
• pp.225-232
• /
• 2022

When we drive a vehicle in an IoT environment, there is a problem in that information of car users is collected without permission. The security measures used in the existing wired network environment cannot solve the security problem of cars running in the Internet of Things environment. Information should only be shared with entities that have been given permission to use it. In this paper, we intend to propose a method to prevent the illegal use of vehicle information. The method we propose is to use attribute-based encryption and dynamic threshold encryption. Real-time processing technology and cooperative technology are required to implement our proposed method. That's why we use fog computing's proxy servers to build smart gateways in cars. Proxy servers can collect information in real time and then process large amounts of computation. The performance of our proposed algorithm and system was verified by simulating it using NS2.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.6
• /
• pp.1443-1448
• /
• 2015

Most of access control systems for underground utility tunnel work through wired network between central system and the automatic switch control unit. However, there are several issues regarding the absence of network infrastructure and an outdoor reader in a relatively unique environment. To solve these issues we propose an authenticated key based smart phone control system for secure access to the underground utility tunnel and this scheme is anticipated providing us with crucial information about a systemic entrance history and effective management procedures of utility tunnel. In addition, the proposed scheme enables to access to secured control system in smart phone based bluetooth network and it provides information about systemic control and history management for the switch controls through smart phone applications.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.3B
• /
• pp.314-324
• /
• 2004

Recently, high-speed internet subscribers have grown continuously, and reached up to 10 millions. But existing network management that is responsible only for user access is confronted with many difficulties, since user access network(xDSL, Cable, B-WILL, and so on) has diversified and value added wired/wireless contents service has developed. In this paper propose the Agent based Inter Networking platform as object-oriented hierarchical system that can provide various service such as access QoS(Quality of Service), customized application service and security service according to user on demand. This system has divided into two parts(user agent and agent management system ＆ local and central management systems). Management system periodically receive status information such as bandwidth, download speed, delay, current service, and so on, and process them, then build a policy based on processed information. According to personal user profile that is generated by this policy, the customized service can be provided for users. And This system adopt the object-oriented modeling in case that system migration and integration, and implement a system that is robust and stable for security through hierarchical server system.