• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2843-2852
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• 2013

In the nested mobile network environment, the mobile node selects one of multiple mobile routers. The MR(Mobile Router) by existing top-down or bottom-up methods may not be the optimal MR if the numbers of mobile nodes and routers are substantially increased, and the scale of the network is increased drastically. Since an inappropriate MR decision causes handover or binding renewal to mobile nodes, determining of the optimal MR is important for efficiency. In this paper, we propose an algorithm that decides on the optimal MR using MR QoS(Quality of Service) information, and we describe how to understand the various structured MLP(Multi-Layered Perceptron) based on the algorithm. In conclusion, we prove the ability of the suggested neural network for a nesting mobile network through the performance analysis of each learned MLP.

• Journal of KIISE:Information Networking
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• v.36 no.3
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• pp.204-211
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• 2009

Proxy Mobile IPv6(PMIPv6) is that network-based mobility management protocol that network supports mobile node's mobility on behalf of the Mobile Node(MN). In PMIPv6 network, data packets from a Correspondent Node(CN) to a MN will always traverse the MN's Local Mobility Anchor(LMA). Even though, CN and MN might be located close to each other or within the same PMIPv6 domain. To solve this problem, several PMIPv6 Route Optimization(RO) schemes have been proposed. However, these RO schemes may result in a high signaling cost when MN moves frequently between MAGs. For this reason, we propose an adaptive route optimization(ARO) scheme. We analyze the performance of the ARO. Analytical results indicate that the ARO outperforms previous schemes in terms of signaling overhead.

• Journal of Power Electronics
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• v.17 no.3
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• pp.821-834
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• 2017

This paper reports on a single-inductor multiple-output step-up converter with digital control. A systematic analog-to-digital-controller design is explained. The number of digital blocks in the feedback path of the proposed converter has been decreased. The simpler digital pulse-width modulation (DPWM) architecture is then utilized to reduce the power consumption. This architecture has several advantages because counters and a complex digital design are not required. An initially designed unit-delay cell is adopted recursively for the construction of coarse, intermediate, and fine delay blocks. A digital limiter is then designed to allow only useful code for the DPWM. The input voltage is 1.8 V, whereas output voltages are 2 V and 2.2 V. A co-simulation was also conducted utilizing PowerSim and Matlab/Simulink, whereby the 55 nm process was employed in the experimental results to evaluate the performance of the architecture.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2195-2200
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• 2008

The use of WLAN technology specially 802.11 b and g has seen huge subscriber growth in a relatively short time period due to low cost and ease of installation of WLAN hardware. These technologies provide multiple data rates ranging from 1 to 54 Mbps depending on modulation used in physical layer. This paper presents the performance of 802.11b and g under different data rates in mobile IPv4 environment. OPNET is used in the study as the network simulator. The performance metrics used in this wort is data traffic received by a WLAN station roaming amongst Access Point(AP) of different ESSs. It is found that much data packets are lost during handover between mobile agents. The traffic received by the roaming station varies based on the data rates provided by two different WLAN technologies.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.85-94
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• 2008

As a variety of wireless network services, such as WLAN, WiBro, cdma2000, and HSDPA, are provided and the range of users' choices for the wireless services are broaden, MCoA (Multiple Car-of Address) concepts that enable users to use wireless interfaces simultaneously have been presented in IETF MONAMI6 WG. Through this scheme, users can access several networks simultaneously by using multiple wireless interfaces. Such various wireless connection technologies continue to advance as they are connected and integrated to All-IP-based core network, and at the same time, heterogeneous networks are being managed overlaid according to the coverage of the wireless connection technologies. Under such circumstances, needs for an integrated architecture have arisen, and thus Wireless service framework is required that effectively manages heterogeneous networks which coexist with next generation's networks for 4G. In this paper, a wireless service framework is suggested in the consideration of current wireless service environment, and the framework covers the schemes to minimize the packet loss caused by handover, and also modified Multiple Care-of Address that helps to select most effective network by considering characteristics of various interfaces as well as users' preferences.

• Journal of Fashion Business
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• v.25 no.4
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• pp.61-78
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• 2021

Gianni Versace is one of the most influential Italian designers between the 1980s and 1990s and a representative person to add sexiness and splendour to Italian fashion. This study aimed to analyze the design identity that resulted in the successful handover to Donatella Versace and to review how effectively differentiated and unique heritage elements of Versace were transferred and operated. Literature reviews were performed to find Gianni Versace's design identity and archive. The scope of this study was Donatella's collection from 2018 to 2020. In particular, Signature, the most remarkable design identity of luxury brands with a visual identity that includes the mark, logo and symbol and design elements such as the item, colour, materials, details, etc., were the special focus. In this study, the elements of the visual identity of the signature were classified with the logo, icon, silhouette, materials, patterns, colours, and changes in details that were applied with the uniqueness and philosophy of the differentiated brand. Donatella Versace empathized with Versace's heritage as the brand heritage recalling Versace's honour in the 1990s and reproduced his honour again by reinterpretation of Versace's design images. Donatella is considered an excellent creative director who leads the brand by keeping the heritage and applying the trends of the times. This study as a case study of Versace has the meaning that Versace has maintained the brand identity starting from Gianni Versace as the first generation and successful takeover after the change of directors upon recreation to meet the modern times.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.81-92
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• 2009

Recently, there is a drastic increase in users interested in real-time multimedia services in the WLAN environment, as the demand of IEEE 802.11 WLAN-based services increases. However, the handoff delay based on 802.11i security policy is not acceptable for the seamless real-time multimedia services provided to MS frequently moving in the WLAN environment, and there is a possibility of DoS attacks against session key derivation process and handoff mechanism. In this paper, a secure and efficient handoff mechanism in the centralized WLAN environment is introduced to solve the security problems. The 4-way Handshake for both mutual authentication and session key derivation is replaced by the 2-way Reassociation process.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.1
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• pp.51-61
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• 2010

Koinonia system is designed to fully utilize the advantage of Binary CDMA so as to guarantee QoS in wireless networks. In this paper, we propose the new network structure based on this system and refer to it as BLAN(Binary CDMA LAN). Although BLAN is similar structure to IEEE 802.11 WLAN, it will ensure the fast handover and QoS. We also propose the AKA(Authentication and Key Agreement) protocol and Reauthentication protocol to be used for communication in BLAN. These protocols are securely and efficiently designed using the user identity module to support the more powerful authentication. Hence, BLAN, including the proposed protocols, will support the high mobility and security. In conclusion, we expect that BLAN can be applied to future infrastructure on special environment, and it can be helpful showing the new network model which alternate WLAN.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.1026-1031
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• 2022

Cognitive Radio Ad-Hoc Networks (CRAHNs) enable to overcome the shortage of frequency resources due to the increase of radio services. In order to avoid interference with the primary user in CRANH, channel sensing to check the idle channel is required, and when the primary user appears, the time delay due to handover should be minimized through fast idle channel selection. In this paper, throughput was improved by reducing the number of channel sensing and preferentially sensing a channel with a high probability of being idle, using reinforcement learning. In addition, we proposed a multi-channel MAC (Medium Access Control) protocol that can minimize the possibility of collision with the primary user by sensing the channel at the time of data transmission without performing periodic sensing. The performance was compared and analyzed through computer simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.65-71
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• 2023

In this paper, the design, fabrication and verification steps of an electronically scanned array antenna(AESA) for a photonics-based Ku-band FMCW radar system is described. The presented system consists of a transmitter and a receiver respectively, which has a same antenna in the transceiver. The designed antenna has 2×8 array configuration and operates at Ku-band. The VSWR(Voltage Standing Wave Ratio) of each 16-radiators and the coupling power between radiators is measured. Also, in order to minimize the radar system damage because of handover power from the transmitter antenna to the receiver antenna when the transmitter works, the isolation between the transmitter antenna and the receiver antenna is optimized by test. As a result, beamwidth, side lobe level and beam steering characteristic are obtained by synthesizing each radiator pattern measurement data after each beam pattern of 16-radiators is measured in the near-field chamber.