• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.25-30
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• 2022

Since Tim Berners-Lee introduced the idea of the web to the world in the late 1980s, the way information is produced, accessed and used has been constantly changing. This was once again an era of upheaval after Apple's Steve Jobs introduced the smartphone to the world in the mid-2000s. Before the advent of smart devices, web browsing was mainly done using desktops. After the advent of this device, the era of solving almost all human needs with a small PC in the palm of your hand has arrived. The necessity of seamless connectivity between devices, which are constantly emerging and evolving, asks our attention more than ever. In this study, we will discuss a case of design and development of a national open access website, which is optimized for dynamic online user behaviors with diverse devices. Our goal is to provide one true web for people to use in their environment. Device makers need to provide products identical to the desktop environment as much as possible. Service providers should also provide services optimized for each device in hyper-connected environments. Providing a web, optimized for user's online context, will eventually result in a sustainable user experience.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.320-323
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• 2008

Due to the improvement of mobile device capabilities, a demand for various contents service is increasing. But the differences from heterogeneous mobile devices force to develop contents which is dependent on a mobile. To solve this problem, adaptation course that reorganize contents by the device capability is needed. In this course, device description is described using device description language but there are some problems that is absence of device description repository and the way to get device description data. In this paper, I suggest device description acquisition module and define the interfaces to access device description repository that I designed and implemented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.7
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• pp.571-579
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• 2013

This paper proposes an energy-efficient mode selection and power allocation scheme in device-to-device (D2D) communication system as an underlay coexistence with cellular networks. We analyze the energy efficiency which is defined as the summation of the energy efficiencies for all devices. The proposed scheme consists of two steps. First, we calculate the transmission power maximizing the energy efficiency for all possible modes of each device. Although the proposed power cannot maximize the system capacity, we prove that the proposed transmission power is the optimal power which maximizes the energy efficiency. In the second step, we select a mode which has the maximal energy efficiency among all possible mode combinations of the devices. Then we can jointly obtain the transmission power and the mode which can maximize the energy efficiency. The proposed scheme has the optimal performance with respect to the energy efficiency and outperforms the conventional schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2091-2096
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• 2008

Due to the improvement of mobile device capabilities, a demand for various contents service is increasing. But the differences from heterogeneous mobile devices force to develop contents which is dependent on a mobile. To solve this problem, adaptation course that reorganize contents by the device capability is hooded. In this course, device description is described using device description language but there are some problems that is absence of device description repository and the way to get device description data. In this paper, I suggest device description acquisition module and define the interfaces to access device description repository that I designed and implemented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.497-505
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• 2015

Existing Wi-Fi networks require users to follow network settings of the AP (Access Point), resulting in inconveniences for users, and the password of the AP is shared by all users connected to the AP, causing security information leaks as time goes by. We propose, in this work, a personalized secure Wi-Fi network, in which each user is assigned her own virtual Wi-Fi network. One virtual Wi-Fi per user makes the user-centric network configuration possible. A user sets a pair of her own SSID and password on her device a priori, and the AP publishes its public key in a suitable way. The AP also maintains an open Wi-Fi channel, to which users can connect anytime. On user's request, the user device sends a connection request message containing a pair of SSID and password encrypted with the AP's public key. Receiving the connection request message, the AP instantiates a new virtual AP secured with the pair of SSID and password, which is dedicated to that single user device. This virtual network is securer because the password is not shared among users. It is more convenient because the network adapts itself to the user device. Experiments show that these advantages are obtained with negligible degradation in the throughput performance.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.305-310
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• 2013

To provide medical services to patients who have a terminal illness, recent hospital patients to monitor the state of the device attached to the body, the body insertion device is. U-Healthcare Environment and hospital officials indiscriminately exploited by the patient's vital information, however, could threaten the patient's life problems are appearing. In this paper, depending on the level of authority, hospital officials, Union of ID-based authentication model is proposed to use a patient's vital information. Union proposed model identify different authentication system is used in hospitals that exist in various forms in a number of ID information, health / medical information sharing between hospitals without exposure to unnecessary personal information, you can be assured of the anonymity. In particular, with easy access to patient information, hospital officials about the malicious act to protect patient information to access level for the rights granted by third parties to prevent easy access.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.7-13
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• 2020

IoT which is the core IT of the 4^th industrial revolution, is providing various services from users in the conversion with other industries. The IoT convergence technology is leading the communication paradigm of communication environment in accordance with the increase of convenience for users. However, it is urgently needed to establish the security measures for the rapidly-developing IoT convergence technology. As IoT is closely related to digital ethics and personal information protection, other industries should establish the measures for coping with threatening elements in accordance with the introduction of IoT. In case when security incidents occur, there could be diverse problems such as information leakage, damage to image, monetary loss, and casualty. Thus, this paper suggests a certificate management technique for safe control over access in IoT-based Cloud convergence environment. This thesis designed the device/user registration, message communication protocol, and device renewal/management technique. On top of performing the analysis on safety in accordance with attack technique and vulnerability, in the results of conducting the evaluation of efficiency compared to the existing PKI-based certificate management technique, it showed about 32% decreased value.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.348-357
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• 2012

Recently, smartphone, notebook, PC and other supporting wireless LAN device have come into wide use. By increasing user that use wireless LAN device, wireless traffic also increased. If wireless traffic through one AP is increase, it causes throughput decrease. To solve this problem, wireless LAN service provider install more AP where overload occurred. But this is not enough. Because stations can't know AP's load factor, and APs do nothing for load balancing. In this paper, we propose Multi-Interface Access Point(MIAP) to solve this problem. MIAP operate same as multiple APs with multi-interface, and MIAP measure each interface's load periodically. If MIAP detect overloaded interface, MIAP transfer station from overloaded interface to under-loaded interface. We conducted an experiment for verifying existing problem, and we found this problem occurred. We plan an experiment scenario for a comparison between existing AP and MIAP, and excute these experiment. In the result, we show MIAP with load balancing can improve total throughput about 72% and stabilize delay jitter than existing AP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2014-2020
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• 2016

In general, automatic access control management system using smart door-lock must be always exposed to security vulnerability during wireless communication based on Bluetooth. In particular, important information such as a secrete key can be exposed to the attacker when the authentication protocol has been operating in the wireless section. Therefore important information exchanged in the radio section needs to be properly encrypted. In order to analyze security vulnerability for automatic access control management system of public facilities such as subway vent, GNU Radio platform and HackRF device will be considered and experimented. Proposed experimental system to perform software based power analysis attack could be very effectively applied. As a result, important information such as packet type, CRC, length of data, and data value can be easily decoded from wireless packet obtained from HackRF device on GNU Radio platform. Constructed experimental system will be applied to avoid some security problems.

• Korean Journal of Materials Research
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• v.32 no.9
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• pp.384-390
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• 2022

A spin coating process for RRAM, which is a TiN/TiO₂/FTO structure based on a PTC sol solution, was developed in this laboratory, a method which enables low-temperature and eco-friendly manufacturing. The RRAM corresponds to an OxRAM that operates through the formation and extinction of conductive filaments. Heat treatment was selected as a method of controlling oxygen vacancy (V_O), a major factor of the conductive filament. It was carried out at 100 ℃ under moisture removal conditions and at 300 ℃ and 500 ℃ for excellent phase stability. XRD analysis confirmed the anatase phase in the thin film increased as the heat treatment increased, and the Ti³⁺ and OH- groups were observed to decrease in the XPS analysis. In the I-V analysis, the device at 100 ℃ showed a low primary SET voltage of 5.1 V and a high ON/OFF ratio of 10⁴. The double-logarithmic plot of the I-V curve confirmed the device at 100 ℃ required a low operating voltage. As a result, the 100 ℃ heat treatment conditions were suitable for the low voltage driving and high ON/OFF ratio of TiN/TiO₂/FTO RRAM devices and these results suggest that the operating voltage and ON/OFF ratio required for OxRAM devices used in various fields under specific heat treatment conditions can be compromised.