• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.99-105
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• 2018

As the Internet of Thing(IoT) technology recently has become a big issue, many researches have been carried out to link the Internet of things with the home network system. Various home network systems are being implemented to connect many devices used in the home with the Internet and to control and operate the devices using a smart phone. However, existing protocols that operate on the Internet are not suitable for a limited environment such as low power, low capacity, and low performance. Therefore, the Internet Engineering Task Force (IETF) Working Group proposed the CoAP/6LoWPAN technology as a suitable protocol for internetworking IoT devices with the Internet in a limited environment and adopting it as a standard. In this paper, a smart home network system is implemented to control and operate various IoT devices in a home using CoAP/6LoWPAN in mobile environment. The performance of HTTP and CoAP such as data transmission time, data transmission rate is analyzed.

• Journal of Electrical Engineering and information Science
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• v.1 no.1
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• pp.82-90
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• 1996

In this paper, we present an analysis of the IS-95 authentication protocol for the Code Division Multiple Access(CDMA) mobile communication network. We propose a mutual authentication protocol, AP-6, to improve the security and correctness. Formal description and verification of the proposed AP-6 are also presented on the basis of the formal logic. It is shown that the proposed AP-6 is more secure and correct than the IS-95 authentication protocol.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.1 no.1
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• pp.51-64
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• 2002

This paper analyzes performance measures of a Bluetooth_based mobile home network system. The home network system consists of terminals with Bluetooth interfaces, access points (AP), a home PC, and a gateway A mobile host in wireless terminals uses Mobile IP for supporting the mobility This paper considers four types of data traffic, which are new connection traffic, handoff traffic, Internet data traffic, and control data traffic and suggests a queueing system model of the home network system, where the AP and the home PC are modeled as M/G/1 with four priority queues and the gateway is modeled as M/G/1 with a single queue The generation rate and service time of individual traffic influence their performance measures. Based ell the suggested model, we propose the elapsed time of data traffic in terms of the number of cells, the number of Home PCs, arrival rates of four types of traffic and the service rates of AP/Home PCs/Gateway To analyze influences on the elapsed time with respect to arrival rate of four types of traffic, some examples are given.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.2811-2830
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• 2017

In this paper, we study the problem of mobile data offloading for a network that contains multiple mobile network operators (MNOs), multiple WiFi or femtocell access points (APs) and multiple mobile users (MUs). MNOs offload their subscribed MUs' data traffic by leasing the unused Internet connection bandwidth of third party APs. We propose a combinatorial auction-based two-stage matching mechanism comprised of MU-AP matching and AP-MNO matching. The MU-AP matching is designed to match the MUs to APs in order to maximize the total offloading data traffic and achieve better MU satisfaction. Conversely, for AP-MNO matching, MNOs compete for APs' service using the Nash bargaining solution (NBS) and the Vickrey auction theories and, in turn, APs will receive monetary compensation. We demonstrated that the proposed mechanism converges to a distributed stable matching result. Numerical results demonstrate that the proposed algorithm well capture the tradeoff among the total data traffic, social welfare and the QoS of MUs compared to other schemes. Moreover, the proposed mechanism can considerably offload the total data traffic and improve the network social welfare with less computation complexity and communication overhead.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.87-95
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• 2014

Under only authorized AP is allowable environment, rogue AP which is generated by a smartphone tethering can be a serious security breach. To solve rogue AP problem, this paper proposes classifying algorithm of Kernel Support Vector Machine using features of RTT data. Through our experiment, we can detect rogue AP from LTE mobile network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.91-96
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• 2018

Recently, as artificial intelligence technology becomes popular, demand for wireless traffic is rapidly increasing. In order to provide services in response to the increase in demand for wireless traffic, telecommunication companies are generalizing the installation of public APs. In order to provide convenience of using wireless APs between communication companies, it is necessary to share the use of APs in public places to efficiently use wireless resources in a public place, to pre-authenticate between wireless APs in a mobile communication service, So as to increase the convenience of the user. In this paper, we propose to share APs in public places through handoff between APs and pre-authentication between carriers in mobile communication services. The simulation results show that the handoff latency is improved by 35.1% and the bandwidth used by the AP selected by the pre-authentication method can utilize more bandwidth than the method of automatically selecting the AP.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.45-51
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• 2010

Appearance of a cloned AP(Access Point) causes MS(Mobile Station) to break an association with a normal AP(Access Point). If signal power of the cloned AP is stronger than that of the normal AP, MS associates with the cloned AP. Therefore, MS is easily exposed to attackers who installed the cloned AP. In this paper, we distinguish cloned AP from normal AP by using the association time and frame sequence number between normal AP and MS, then isolates the cloned AP. The simulation by NS-2 shows that our mechanism isolates efficiently a cloned AP and builds safer wireless LAN environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.595-598
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• 2014

In order to provide the Mobile Stations operating in IEEE 802.11 Wireless LAN network with seamless handover, a comprehensive study on the functions of handover considering various networking environments and characteristics of Mobile Stations is required. Note that the channel scan process finding a new AP takes the major portion of handover time, and this is the most significant issue with seamless handover for real-time multimedia service in WLAN environment. In this paper the functions required to provide seamless handover in IEEE 802.11 WLAN network are identified, and a new scanning technique is proposed with which the Mobile Stations can selectively scan the channels to reduce the channel scan time in various network environments. Here each Mobile Station awares of the channels the neighbor APs are using by scanning them in advance according to the proposed technique. Afterwards, when handover is actually required, the optimal AP is decided quickly by scanning only the predetemined group of channels and order of scan without unnecessary scan of all the channels. In addition, proposes to enter the Scan Trigger Value and Handover Threshold Value in mobile phones in order to prevent the phenomenon can not handover.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.53-61
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• 2018

Recently, technologies related to the Internet of Things have developed rapidly and research on mobile environment home network systems is actively in progress. The Internet Engineering Task Force (IETF) Working Group proposed the CoAP/6LoWPAN technology as a suitable protocol for internetworking IoT devices with the Internet in a limited environment and adopting it as a standard. However, the existing home network systems hardly include security protocols. IETF recommends DTLS(Datagram Transport Layer Security) on UDP as security protocol suitable for IoT environments. In this paper, smart home network system based on CoAP/6LoWPAN by using DTLS is implemented in mobile environments. The data transfer time is measured according to each procedure of the DTLS protocol and the need to improve DTLS protocol is suggested.

• Journal of Information Processing Systems
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• v.2 no.3 s.4
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• pp.159-162
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• 2006

Wireless LANs are becoming more widespread because of the rapid advance of wireless technologies and mobile computers. In this paper, we present the design and implementation of a system to help mobile users to select the most competent AP. By monitoring the network traffic of APs within the local LAN in real time, this system offers the mobile user the network utilizations, locations, and signal strengths of APs online. Based on the information, the user can select a competent AP with a high wireless bandwidth. Finally, we verified the accuracy of monitoring and calculating with regard to the utilizations of APs through real experiments.