• Journal of information and communication convergence engineering
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• 제10권2호
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• pp.156-161
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• 2012

An increasing number of people who use a smart phone or tablet PC are accessing wireless networks in public facilities including cafes and shopping centers. For example, iPhones and Android Phones have been available since 2010. However, security incidents may occur through all sorts of malicious code infection of users' personal information during the use of an insecure wireless network. In this paper, we will describe the Wi-Fi protected access (WPA) and WPA2 encryption systems used to access a wireless network from a smart phone and tablet PC, and demonstrate the access point (AP) hacking process in a wireless network to which a password is applied on the basis of the analyzed WPA and WPA2 passwords. We will analyze the method of successful AP hacking and propose an approach to enhancing wireless LAN security. This study will contribute to enhancing the security and stability of wireless networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.3131-3149
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• 2016

In-band Full-duplex (IBFD) wireless communication allows improved throughput for wireless networks. The current Half-duplex (HD) medium access mechanism Request to Send/Clear to Send (RTS/CTS) has been directly applied to IBFD wireless networks. However, this is only able to support a symmetric dual link, and does not provide the full advantages of IBFD. To increase network throughput in a superior way to the HD mechanism, a novel three-way handshaking access mechanism RTS/SRTS (Second Request to Send)/CTS is proposed for point to multipoint (PMP) IBFD wireless networks, which can support both symmetric dual link and asymmetric dual link communication. In this approach, IBFD wireless communication only requires one channel access for two-way simultaneous packet transmissions. We first describe the RTS/SRTS/CTS mechanism and the symmetric/asymmetric dual link transmission procedure and then provide a theoretical analysis of network throughput and delay using a Markov model. Using simulations, we demonstrate that the RTS/SRTS/CTS access mechanism shows improved performance relative to that of the RTS/CTS HD access mechanism.

• International Journal of Advanced Culture Technology
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• 제6권4호
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• pp.65-70
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• 2018

Wireless data broadcasting system that can support any number of clients is the effective alternative for the challenge of scalability in ubiquitous computing in IoT environment. In the system, it is important to evaluate quickly the performance parameter, the access time that means how quickly the client access desired data items. In this paper, we derive the mathematical model for the access time in the wireless data broadcast system adopting two-tier indexing scheme. The derived model enables to evaluate the access time without the complicated simulation. In order to evaluate the model, we compare the access time by the model with the access time by the simulation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.82-86
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• 2001

This papers deals with feasibility study of wireless motion control. Wireless telecommunication advances with development of IT technology and extends more and more areas. So we selected Bluetooth out of the technologies(Bluetooth, SWAP(SharedWireless Access Protocol), IrDA(Infra Red Data Association), WLAN(Wireless Local Area Network)) which was developed for local data communication and set up simple experimental system for wireless data transfer and server and client program for wireless data transfer was wrote. We successfully transferred some data wirelessly with this program.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2085-2094
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• 2012

본 논문에서는 다수 무선 접속 기술 (Radio Access Technology; RAT)이 통합되어 운용되는 셀룰러 네트워크에서 차세대 이동통신 네트워크 진화 방향인 디지털 유닛 (DU)-라디오 유닛 (RU) 분리 구조를 기본으로 무선 액세스 네트워크 가상화 알고리즘을 제안한다. 제안 무선 액세스 네트워크 가상화 알고리즘은 크게 기본 액세스 네트워크 가상화, RAT 가상화, 액세스 경로 이주 알고리즘으로 구성되고, 순차적인 수행을 통하여 최종 무선 액세스 네트워크 가상화가 이루어진다. 제안 무선 액세스 네트워크 가상화 알고리즘은 3GPP LTE와 WiMAX의 두 무선 접속 기술을 예제로 한 시스템 레벨 시뮬레이션을 통하여 시스템 수율 측면에서 성능이 평가된다. 이 때, 네트워크 트래픽 로드의 비대칭성에 따른 두 가지 시나리오를 고려하고, 제안 무선 액세스 네트워크 가상화 알고리즘은 비대칭적 네트워크 트래픽 로드와 사용자 분포 상황에서도 상당한 성능 이득을 성취한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권4호
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• pp.1832-1853
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• 2018

The personal health record (PHR) system is a promising application that provides precise information and customized services for health care. To flexibly protect sensitive data, attribute-based encryption has been widely applied for PHR access control. However, escrow, exposure and abuse of private keys still hinder its practical application in the PHR system. In this paper, we propose a coordinated ciphertext policy attribute-based access control with user accountability (CCP-ABAC-UA) for the PHR system. Its coordinated mechanism not only effectively prevents the escrow and exposure of private keys but also accurately detects whether key abuse is taking place and identifies the traitor. We claim that CCP-ABAC-UA is a user-side lightweight scheme. Especially for PHR receivers, no bilinear pairing computation is needed to access health records, so the practical mobile PHR system can be realized. By introducing a novel provably secure construction, we prove that it is secure against selectively chosen plaintext attacks. The analysis indicates that CCP-ABAC-UA achieves better performance in terms of security and user-side computational efficiency for a PHR system.

• Journal of Ubiquitous Convergence Technology
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• 제2권1호
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• pp.51-55
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• 2008

A digital home is a ubiquitous environment that is expected to be realized in the near future. All information appliances in a house are connected to each other through wired and/or wireless home networks. Authenticated user can access the various services provided by the digital home, and the access is not restricted by equipment, time, or location. The technologies that form the digital home can be grouped into two categories: wired networking technologies and wireless networking technologies. For the purpose of ubiquitous environments, wireless-networks offer suitable and seamless high-quality services. A wireless LAN can be created simply by equipping a single access point. For that reason, the cost of establishing such a network is low and using it is easy. Of course, there is an exciting new wireless technology. It is the Ultra Wide Band (UWB). However, it is not enough to bring wireless convenience, although offering a broad range of high-speed data transfer capabilities, Because of unstable. Thus, of the wireless-networking systems, we focus on the wireless LAN. We quantitatively analyze its capabilities. The dynamic and adaptive wireless LAN provides a foundation for the evolution toward the next generation of wireless and adaptive networks. The difference between wired LAN and wireless LAN in upload and download rates is small. Although the wireless LAN experiences a greater loss rate than the wired LAN, the difference is minimal. We conclude that a wireless LAN is suitable for use in an apartment environment.

• 산업기술연구
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• 제28권B호
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• pp.33-37
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• 2008

Recently, there have been intensive researches on the wireless Internet access through WiFi WLAN using WiRro network as backhaul link in the Internet service providing business area. However, in the wireless Internet access method, we need to solve the compatibility problem for different user authentications between licensed WiBro network and unlicensed WiFi network for billing and user management. In this paper, we propose an authentication method for WiFi users by BWAN operators through WiNNERs which is RS connecting the two networks, and discuss the effectiveness of the method.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2150-2162
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• 2012

차세대 모바일 인터넷의 진화에 따라 2G, 3G, 4G, B4G 이동통신 무선접속네트워크가 공존하게 되며, 기존의 통신 서비스 제공자들은 통합 서비스 제공자로 융합되고, 다수의 가상 서비스 제공자들이 발생하게 될 것으로 예상된다. 이러한 복잡한 미래의 융합 서비스를 제공하기 위해서 미래 인터넷에서는 무선 액세스 네트워크가 융합되고 다양한 서비스 제공자들에 의해 공유되는 무선 네트워크 가상화가 필수적이다. 따라서 본 논문에서는 미래 무선 액세스 네트워크 상에서 여러 서비스 제공자들의 다양한 무선 액세스 기술들이 유연하게 통합 운영될 수 있는 무선 액세스 네트워크 가상화를 위한 망 구조와 가상화 시나리오에 대해서 고찰한다. 본 논문에서 도출된 차세대 이동통신 네트워크를 위한 무선 액세스 망 구조 및 가상화 시나리오는 앞으로 무선 액세스 네트워크 가상화 알고리즘 개발을 위한 기틀 역할을 할 수 있을 것으로 기대된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.209-211
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• 2005

This paper proposes a adaptive medium-access control(MAC) protocol designed for low-power wireless multi-hop sensor networks which is used for connecting physical world and cyber computing space. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining inactive for long time, but becoming suddenly active when specific event is detected. These characteristics of multi-hop sensor networks and applications motivate a MAC that is different from traditional wireless MACs about power conservation scheme, such as IEEE 802.11. Proposed MAC uses a few techniques to reduce energy consumption. Result show that proposed MAC obtains more energy savings.