• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.208-211
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• 2000

We prepared Co-Cr-Ta and Co-Cr-Ta/Ti thin film for perpendicular magnetic recording media by facing targets sputtering system (FTS system). Ti underlayer effects on crystallographic and magnetic characteristics of Co-Cr-Ta perpendicular magnetic recording media have been investigated. Crystallgraphic and magnetic characteristic of prepared thin films were evaluated by x-ray diffractometry(XRD), vibrating sample magnetometer(VSM) and kerr hysteresis loop measurement. The coercivity and anisotropy field increase by introduced Ti underlayer when substrate temperature is higher than 150$^{\circ}C$. The c-axis dispersion angle and grain size of Co-Cr-Ta/Ti thin film is decrease than Co-Cr-Ta when substrate temperature is higher than 100$^{\circ}C$. Consequently, the use of a Ti underlayer highly orientated can be improved crystallographic and magnetic characteristics of Co-Cr -Ta perpendicular media layer.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.260-263
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• 2021

코로나19로 인해 출입 관련 시스템도 비대면으로 변화하고 있다. 변화에 맞추어 비대면으로 출입자를 관리할 수 있는 프로그램을 개발하여 접촉 위험을 줄이고 출입자 모니터링에 실용성을 제공하고자 한다. 본 연구에서는 Raspberry Pi 카메라에 Alchera Face Authentication API를 적용하여 얼굴인식을 실시하며 정보를 AWS 클라우드에서 저장·관리 하는 시스템을 개발하였다. 챗봇 서비스를 통해 출입자를 확인할 수 있으며 메신저에서 쉽게 클라우드에 접근하여 정보를 확인할 수 있게 하였다. 이를 통해, 특정 장소를 비대면으로 관리하며 간편하게 출입자를 모니터링할 수 있을 것으로 기대한다.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.4
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• pp.568-576
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• 2017

This paper presents a clock and data recovery circuit with an adaptive loop bandwidth calibration scheme and the idle power saved frequency acquisition. The loop bandwidth calibration adaptively controls injection currents of the main loop with a trimmable bandgap reference circuit and trains the VCO to operate in the linear frequency control range. For stand-by power reduction of the phase detector, a clock gating circuit blocks 8-phase clock signals from the VCO and cuts off the current paths of current mode D-flip flops and latches during the frequency acquisition. 77.96% reduction has been accomplished in idle power consumption of the phase detector. In the jitter experiment, the proposed scheme reduces the jitter tolerance variation from 0.45-UI to 0.2-UI at 1-MHz as compared with the conventional circuit.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1264-1274
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• 2015

Human action recognition received many interest in the computer vision community. Most of the existing methods focus on either construct robust descriptor from the temporal domain, or computational method to exploit the discriminative power of the descriptor. In this paper we explore the idea of using local action attributes to form an action descriptor, where an action is no longer characterized with the motion changes in the temporal domain but the local semantic description of the action. We propose an novel framework where introduces local action attributes to represent an action for the final human action categorization. The local action attributes are defined for each body part which are independent from the global action. The resulting attribute descriptor is used to jointly model human action to achieve robust performance. In addition, we conduct some study on the impact of using body local and global low-level feature for the aforementioned attributes. Experiments on the KTH dataset and the MV-TJU dataset show that our local action attribute based descriptor improve action recognition performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.529-546
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• 2012

To address the need for autonomous control of remote and distributed mobile systems, Machine-to-Machine (M2M) communications are rapidly gaining attention from both academia and industry. M2M communications have recently been deployed in smart grid, home networking, health care, and vehicular networking environments. This paper focuses on M2M communications in the vehicular networking context and investigates areas where M2M principles can improve vehicular networking. Since connected vehicles are essentially a network of machines that are communicating, preferably autonomously, vehicular networks can benefit a lot from M2M communications support. The M2M paradigm enhances vehicular networking by supporting large-scale deployment of devices, cross-platform networking, autonomous monitoring and control, visualization of the system and measurements, and security. We also present some of the challenges that still need to be addressed to fully enable M2M support in the vehicular networking environment. Of these, component standardization and data security management are considered to be the most significant challenges.

• Journal of Sensor Science and Technology
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• v.21 no.5
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• pp.352-358
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• 2012

A sensor network system can be an efficient tool for healthcare telemetry for multiple users due to its power efficiency. One drawback is its limited data size. This paper proposed a real-time application of data compression/decompression method in u-Health monitoring system in order to improve the network efficiency. Our high priority was given to maintain a high quality of signal reconstruction since it is important to receive undistorted waveform. Our method consisted of down sampling coding and differential Huffman coding. Down sampling was applied based on the Nyquist-Shannon sampling theorem and signal amplitude was taken into account to increase compression rate in the differential Huffman coding. Our method was successfully tested in a ZigBee and WLAN dual network. Electrocardiogram (ECG) had an average compression ratio of 3.99 : 1 with 0.24% percentage root mean square difference (PRD). Photoplethysmogram (PPG) showed an average CR of 37.99 : 1 with 0.16% PRD. Our method produced an outstanding PRD compared to other previous reports.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.692-695
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• 2011

미디어 서비스 및 디스커버리 관련 기술 개발은 주로 DTV, 인터넷, 개인 모바일 멀티 미디어 기기 중심의 미디어 서비스가 주를 이루고, 이러한 미디어 서비스들은 홈 네트워크 환경과 융합하여 홈 미디어 서비스의 새로운 서비스를 창출하고 있다. 개인들은 이미 많은 이동형 멀티미디어 기기들을 소유하기 시작했고, 각 기기마다 플레이 가능한 컨텐츠 포맷, 라이선스 구조, 상세정보를 기술하는 정보들이 서로 상이하게 제공되기도 한다. 이런 멀티디미어 환경의 발달과 함께, 개인간 또는 개인이 소유한 기기간 컨텐츠를 공유하고자 하는 요구가 생겨나고, 개인 맞춤을 위한 서비스를 받고자 소유한 개인 컨텐츠 포맷 및 라이선스 파일들 개인정보와 콘텐츠를 기술하는 메타 데이터들은 DRM 정보, 개인의 습성 및 취향 등에 대한 개인 정보를 포함하고 있어 보안 및 보호가 필요하다. 따라서 IPTV 환경에서 이종 DRM이 설치된 기기사이에 컨텐츠 상호 연동 방에 대한 연구를 하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.689-691
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• 2011

Due to the rapid development of Information and communication, the technology of multimedia presentation technology is evolving into the service that user can actively, realistically enjoy and play based on user's preference and taste not only for User's passive service. Especially, the industry related the realistic multimedia service that supports targeting Human emotion with the property of Human hearing is expected to be formed of the high value-added premium market. Audio technology is affected on human's emotion and the viewing environment around than video technology. Also the audio technology compared to video technology is a research part that appeals to human emotion and emphasize on psychological aspects. With this viewpoint, the development of intelligent and realistic audio technology needs highly specialty. In this study, "intelligent real-sound presentation technology" that support high quality and realistic audio and the "core technologies" that are composing of this will be introduced.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.685-688
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• 2011

앞으로의 멀티미디어 기기시장은 기존의 단순 복합 디지털 기기들이 아닌 사용자 감성 및 취향 제어가 가능한 인간 친화적 지능형 멀티미디어 기기가 주류를 이룰 것이다. 이미 IT 기능이 기존의 '정보의 소통'에서 '감성의 소통'으로 진화 중에 있으며, 미래시대에는 느낌까지 디지털 신호로 전달 가능한 기술이 발달 될 것이다. 이에 맞추어 사람의 감성, 주변 분위기, 섬세한 공간 정보를 전달하는 사실적인 오디오 개발 및 인프라가 구축되어 모든 멀티미디어 제품에 적용된다면, 사용자는 보다 현장감 있게 멀티미디어를 즐길 수 있을 것이다. 최근 스마트폰의 확산과 더불어 각종 다양한 음악서비스를 제고하는 웹/앱 형태의 어플리케이션이 증대되고 있는 바, 본 논문에서는 안드로이드 기반 스마트 모바일 기기에서 다양한 오디오 정보를 청취자에게 제공하고 이를 활용하여 청취자가 다양하게 오디오 재생 / 제어하여, 일방적으로 청취자가 오디오를 듣는 수준이 아니라 청취자 취향에 따라 다양하게 오디오를 감상 할 수 있는 서비스를 구현하였다.

• International Commerce and Information Review
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• v.6 no.2
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• pp.85-105
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• 2004

International electronic commerce is different with international commerce in the aspect using electronic media and non-face transaction so there are some problems as authentication, integrity and non-reputation. These problems of electronic document and signature are resolved from electronic certification system. To introduce and develop the electronic certification in the international electronic commerce, it needs to authorize and operate certification authority under the uniform regulation base. But, because the laws and guidelines that related to electronic certification system are different among the nations and international organizations, it needs to compare each nation's law or guideline. In conclusion, to resolve problems of certification and develop certification system in the international electronic commerce, we make uniform rule of international electronic certification and harmonize the technology of electronic certification.