• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.892-899
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• 2006

In this paper, we propose an automatic switching technology between the ad-hoc and the infrastructure modes without user intervention in the IEEE 802.11b wireless LAN. Also, we design our proposed technology and implemented on the Linux machine. For this operation, the area within an Access Point (AP) coverage is defined as a switching area, and a node without any transmission in this area is assumed to be able to relay frames between the AP and nodes in the shaded area that is outside the coverage and cannot reach the AP. By using the proposed technology, it is possible to provide the seamless Internet access service to nodes at the ad-hoc mode in the shaded area. In this paper, we explains the operation of the detection method of the switching area, presents the flowchart and implementation environment. To prove the operation of our technology, we obtain the results of captured packets transmitted between nodes and throughput results through ftp transmission experiment. Hence, we can see that our proposed scheme can be improve the wireless access service in wireless and mobile networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.441-450
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• 2006

WiBro(Portable Internet Service) is service being capable to provide a high data rate wireless internet access with Personal Subscriber Station under the stationary or mobile environment, anytime and any where. It will fill the gap between very high data rate wireless local area networks and very high mobility cellular systems. The security is an important point of WiBro providing high data and mobile wireless services. This paper proposes user authentication mechanism of WiBro wireless networks applied EAP-AKA authentication protocol. As a result of Wireless authentication based on EAP-AKA, this mechanism is capable to be used in WiBro-WLAN-3GPP interworking scenario as well as the WiBro authentication mechanism.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.69-77
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• 2013

This research validates the correlation between usability and functional attributes whilst comparing the degree of satisfaction of information framework used in museum mobile apps via usability evaluation in pre-visit setting. In cases of Bilbao Guggenheim and American Natural History Museum apps, the degree of satisfaction measured for information service, functional attributes, motivation for actual museum visit and during-visit usability of the apps were all highly evaluated. Such evaluation data indicates the increased usability of apps when mobile applications take user-friendly design that intuitively reflect users' interests and needs. After thorough analysis of correlation between usability and fictional attributes, data pointed to more meaning relationships existed in non-intrusiveness and personalization than other functional attributes. In conclusion, we were able to acknowledge the usability of museum mobile apps depends upon the interaction between content and functional attributes rather than entertainment factor and technology.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.167-174
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• 2005

With the progress of portable appliances such as cell phone and handhold PC, the popularization of Personal Area Network (PAN) and the diversification of services that are based on Personal Mobile Gateway (PMG) . To use home services at any time regardless of their Position, it needs a virtual home network that a home network and outside networks are finally integrated. Although interoperability among home appliances reached their service stage, research for services and middleware for new small scale network such as PAN is at an early stage. Traditional home network service/connection methods, terminal control schemes, and middlewares must be extended to accommodate PMG-based PAM. In this paper, we propose an integrated virtual home network Platform that guarantees seamless connections between home network and PAM. We also analyze indispensable functions and presents functions that should be added existent home gateway or home sewer by function.

• Journal of Digital Contents Society
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• v.16 no.6
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• pp.871-882
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• 2015

AIS-ASM is one of the studies to provide a variety of maritime safety information as well as the information on a ship's position that is their own function, and AIS-ASM has been implemented with adjustment of the relevant regulations since 2004. However, it was reported that the increased use of ASM message on the existing AIS channel affects the part of the existing AIS own function such as the transmission of the ship's position and safe-related information. Also, seamless MSP service is difficult to provide at a low transmission rate of the existing AIS channel. This study aims to reduce the marine officer's workload through automating captain's mandatory reporting items using the one of the next maritime digital communication technology (ASM2.0). For this purpose, we designed and realized the ASM2.0 protocol through analyzing domestic regulations about passenger flight and AIS-ASM message.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.4
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• pp.78-85
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• 2011

In vehicle ad-hoc network (VANET) environments, traffic related information such as accident information, emergency information and real time traffic condition have to be delivered to on-board-unit (OBU) or/and road-side-equipment (RSE) for preventing traffic accidents in advance. In this paper, we introduce a Multi-Channel MAC (MCM) since the existing single channel operation may cause packet transmission delay and unexpected communication failure. To offer a seamless safety message transmission during the various services, it is necessary to manage the MAC scheduler in wireless access in vehicular environments (WAVE) systems. The MCM consists of MAC softwares and MAC hardwares where the former and the later ones are implemented with real time operation system based C language and FPGA module with VHDL language, respectively. The performance and QoS are verified by practical measurements and compared with the scheme using single channel operation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.411-419
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• 2008

As the set of new mobile data networking service technologies, such as WiBro, mobile WiMAX and WCDMA-HSDPA, have been introduced in recent years, IP mobility management protocols which aim to provide seamless IP service over the mobile networking environment become one of the important building blocks for the successful mobile networks. IETF has introduced a basic mobility management protocol over IPv6 (MIPv6) and a set of enhanced protocols such as FMIPv6 and HMIPv6, followed by FHMIPv6, S-MIPv6 and HIMIPv6 which combine the benefits of the basic protocols. We have studied the impact of the various IP mobility management protocols over TCP sessions through extensive simulations with ns-2. Our simulation results show that TCP performance with the HIMIPv6 outperforms MIPv6, FMIPv6 and HMIPv6 over the various TCP protocols, due to its efficient combination of the hierarchical mobility management scheme of the HMIPv6, the predictive handover scheme of the FMIPv6 and the fast simulcasting scheme of the S-MIP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.652-662
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• 2016

This paper proposes a user mobility management scheme which supports seamless service even if a user changes his accessing terminal in service in IP-based convergence network. Most of ongoing researches concerning mobility management as well as the existing mobility schemes have been focused to support terminal mobility. It is limited to support a variety of mobility types such as user mobility. The proposed scheme uses the mapping relationship between UID(User Identifier), user specific identifier and TID(Terminal Identifier), specific terminal identifier and forms packet address with user specific permanent 3 layer address for session continuity in case of user mobility. We numerically analyze and compare handover signaling cost between the existing user mobility scheme and the proposed scheme. The result shows that the proposed scheme has lower handover signaling cost than the existing one, [1].

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.1-7
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• 2019

Recently, multimedia streaming service has been activated, and the demand for high-quality multimedia convergence contents services is predicted to increase significantly in the future. The issues of the increasing network load due to the rise of multimedia streaming traffic must be addressed in order to provide QoS guaranteed services. To do this, an efficient network resource management and mobility support technologies are needed through seamless mobility support for heterogeneous networks. Therefore, in this paper, an MIH technology was used to recognize the network situation information in advance and reduce packet loss due to handover delays, and an ACLMIH-FHPMIPv6 is designed that can provide an intelligent interface through introducing a hierarchical mobility management technique in FPMIPv6 integrated network.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.330-336
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• 2023

Rapid urbanization is rapidly progressing around the world, and urban problems such as traffic congestion, environmental pollution, and noise pollution are emerging, due to this urban concentration phenomenon, logistics and transportation costs are increasing. Urban Air Mobility(UAM) is a three-dimensional futuristic urban transportation that is expected to become an important transportation axis of smart cities as a service(MaaS) linked to roads, railways, and personal transportation. However, as of July 2023, research on airspace systems, Bertieport design, navigation, and communication for UAM operation is actively being conducted, but little research has been conducted on the concept of pilot education and training and education and training programs. Therefore, this paper aims to present a suitable plan for the domestic pilot training system through SWOT analysis of vertical takeoff and landing(VTOL) pilot education and training programs in the United States and Europe.