• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.222-225
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• 2001

Policy introducing open access to the wireless network has been under discussion in the Korean mobile telecommunications industry. The policy, which directs mobile operators to allow mobile portals other than their own ones to access their network and subscribers, is expected to vitalize mobile Internet market through competition among portals. This study analyzes the impact of the policy in terms of welfare of mobile Internet users and profit of mobile contents providers. We also cover the influence of mobile Internet fee on anticipated results of the policy

• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1545-1554
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• 2018

In order to support the mobility of the wireless devices, at least two APs (Access Points) must be arranged in a single AP area to maintain communication area. In the WLAN (Wireless LAN) environment, seamless handover is one of the most important issues in terms of effective utilization of wireless networks and maximization of services for users. On the other hand, SDN (Software-Defined Networking), which is emerging rapidly in recent years, is revolutionizing network management in terms of flexibility, fine control, and convenience. SDN originally reduces latency time or increases network robustness by real-time flow table control reducing or bypassing paths between switches in LAN-based data centers. In this study, we apply OpenFlow, a SDN platform focused on wired LAN, to a dense WLAN environment using legacy APs to implement and evaluate seamless handover for streaming services of digital contents.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.115-129
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• 2007

The ubiquitous and autonomic computing environments is open and dynamic providing the universal wireless access through seamless integration of software and system architectures. The ubiquitous computing have to offer the user-centric pervasive services according to the wireless access. Therefore the roaming services with the predefined security associations among all of the mobile devices in various networks is especially complex and difficult. Furthermore, there has been little study of security coordination for realistic autonomic system capable of authenticating users with different kinds of user interfaces, efficient context modeling with user profiles on Smart Cards, and providing pervasive access service by setting roaming agreements with a variety of wireless network operators. This paper proposes a Roaming Coordinator-based security management framework that supports the capability of interoperator roaming with the pervasive security services among the push service based network domains. Compared to traditional mobile systems in which a Universal Subscriber Identity Module(USIM) is dedicated to one service domain only, our proposed system with Roaming Coordinator is more open, secure, and easy to update for security services throughout the different network domains such as public wireless local area networks(PWLANs), 3G cellular networks and wireless metropolitan area networks(WMANs).

• ETRI Journal
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• v.37 no.4
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• pp.804-812
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• 2015

Energy harvesting (EH) technology in the field of wireless sensor networks (WSNs) is gaining increasing popularity through removing the burden of having to replace/recharge depleted energy sources by energy harvester devices. EH provides an alternative source of energy from the surrounding environment; therefore, by exploiting the EH process, WSNs can achieve a perpetual lifetime. In view of this, emphasis is being placed on the design of new medium access control (MAC) protocols that aim to maximize the lifetime of WSNs by using the maximum possible amount of harvested energy instead of saving any residual energy, given that the rate of energy harvested is greater than that which is consumed. Various MAC protocols with the objective of exploiting ambient energy have been proposed for energy-harvesting WSNs (EH-WSNs). In this paper, first, the fundamental properties of EH-WSN architecture are outlined. Then, several MAC protocols proposed for EH-WSNs are presented, describing their operating principles and underlying features. To give an insight into future research directions, open research issues (key ideas) with respect to design trade-offs are discussed at the end of this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1996-2001
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• 2006

Open System Authentication Method, Shared Key Method, Mac Based Authentication Method are very hard to use in wireless network that needs security. So now, many researches have been performed about 802.1x and user authentication method applying PKI. but certificate verification protocol has been used abolished list called CRL since it's first usage of PKI, there were still has a problem about distribution point. This paper applied CVS to use CA direct not to use CRL and OSCP server in order to improve this problems. Also It suggested the system that can make authentication steps more shorter using authentication server and Mutual authentication system by public certificate(small size/low speed wireless terminal can access to wireless network fast and safely)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.241-244
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• 2013

These days wireless network devices (smartphones, tablet PC, laptop) are being utilized more frequently. In line with the increasing number of users of a wireless network, the usage of wireless access points is also increasing. Nowadays as nationwide wireless network services being made available, wireless networks are increasingly being used due to the lower costs of building faster and affordable private or carrier networks. However wireless security is not keeping up with this development. Many use open networks where anyone can join, meanwhile for those using wireless security protocols there is the problem of managing the password. In this paper, we analyze the problems of trying to build a user authentication system using an access point and the RADIUS server.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1143-1150
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• 2017

In this paper, we proposed a method to display a hazard warning of hacking in the UX(: User Experience) concept level for non experts in the open Wi-Fi access area. According to the dangers of the AP raised by capture, we developed an application that provides a warning pop-up on the danger of hacking before using for APs that are distinguished by color and selected.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.275-276
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• 2015

네트워크 가상화를 위한 대표적인 개방적 아키텍처로 OpenFow를 들 수 있다. OpenfFow는 가상 네트워크(Software Defined Network) 개념을 실현하기 위한 랜 스위치 제어 프로토콜의 집합체로서 데이터 센터 등 주로 유선랜 환경을 목표로 설계되어 활용되고 있다. 이 논문에서는 OpenFlow를 무선랜의 AP(Access Point)에 적용하여 WiFi 디바이스들로 구성된 가상 무선 네트워크 관리 프레임을 구현한다. 구현된 관리 프레임은 WiFi 디바이스들의 토폴로지와 트래픽 상황을 중앙 관제 센터에서 모니터링할 수 있고, 플로우 경로를 설정함으로써 라우터를 경유하지 않고 AP 수준에서 스위칭(라우팅)이 가능하여 전체적인 트래픽 혼잡을 크게 줄일 수 있다.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.47-58
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• 1999

In this paper, we design the radio interface protocols of wideband Wireless Local Loop(WLL) that uses wideband Code Division Multiple Access(CDMA), and propose the random access procedures on access channel and analyze the performance of the channel. The structure of radio interface protocols are designed by three modular parts to meet the requirements of IMT-2000 : radio resource controlling part that depends on the radio resources, connection controlling part that is independent of the radio resources, and application part that supports the interface between different parts and user terminals. In addition, we propose the random access procedures on access channel and analyze the performance of the channel. We assume that both near-far effect and shadow fading can be compensated by open loop power control. We observe that the number of access probes(delay) depend on the initial mobile transmission power and power increment, and the poor estimation of initial mobile transmission power might increase the average number of access probes.

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.562-566
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• 2011

As telecommunication technologies in telemedicine services are developed, the expeditious development of wireless and mobile networks has stimulated wide applications of mobile electronic healthcare systems. However, security is an essential system requirement since many patients have privacy concerns when it comes to releasing their personal information over the open wireless channels. Due to the invisible feature of mobile signals, hackers have easier access to hospital networks than wired network systems. This may result in several security incidents unless security protocols are well prepared. In this paper, we analyzed authentication and authorization procedures for healthcare system architecture to apply secure M-health systems in the hospital environment. From the analyses, we estimate optimal requirements as a countermeasure to its vulnerabilities.