• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1965-1966
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• 2008

The manipulation of Boolean functions is a fundamental part of computer science, and many problems in the design and testing of digital systems can be expressed as a sequence of operations. It is mainly a paper of our research on the techniques of Boolean function manipulation using Binary Decision Diagram(BDDs) and their applications for VLSI CAD System. In many practical applications related to digital system design, it is a basic technique to use ternary-valued functions. In this paper, we discuss the methods for representing logical values.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.356-363
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• 2006

The demand for digital multimedia service using Ka band satellite communication are growing rapidly. So, in this paper, we have analyzed rain attenuation with typical model, and proposed prediction model of rain attenuation in high frequency(20 GHz). This paper illustrates Korea rain attenuation characteristics at the Ka band Koreasat beacon frequency based on the theoretical and empirical approaches and seek for efficient techniques by rain attenuation estimate and analyzed performance of adaptive modulation system. Propose prediction model of rain attenuation and parameter of satellite link can be available for the Ka band satellite communication.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.397-398
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• 2014

최근 공공장소에서 디지털액자와 같은 디스플레이 제품에 대한 상용화가 늘어나는 추세이다. 버스, 지하철 등 교통정보를 표시하는 디스플레이 장치에 광고가 사진이나 문자 형태로 보여 지게 된다. 하지만 이러한 시스템들은 해당 기기들의 관리자에 의해 PC로 제어하게 되는데 그 방법과 장소가 다소 제한적이기 때문에 불편 할 수 있다. 따라서, 본 논문에서는 스마트 폰으로 TCP/IP 통신을 통해서 무선네트워크 방식으로 디지털액자를 쉽고 편리하게 제어 하고자 한다. 추가적으로 가정이나 회사 등의 환경에서도 적용하여 손쉽게 누구나 디지털액자에 모바일 애플리케이션을 이용하여 이미지를 등록, 편집 등 편리하게 관리 할 수 있도록 디지털액자와 모바일 애플리케이션을 설계 및 구현하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1934-1939
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• 2006

Current digital communication system is selecting very various digital Modulation way. Need linear power amplifier necessarily to reduce interference for contiguity channel maximum in this communication system and at the same time, power amplifier of high efficiency is required. In this paper Compare with result of equilibrium power amplifier that design Doherty power amplifier of way that linearity and efficiency are improved at the same time through simulation optimization techniques and at the same time design through simulation, efficiency 20% linearity showed 10dB that is improved.

• ETRI Journal
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• v.33 no.3
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• pp.326-334
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• 2011

This paper outlines the time jitter effect of a sampling clock on a software-defined radio technology-based digital intermediate frequency (IF) transceiver for a mobile communication base station. The implemented digital IF transceiver is reconfigurable to high-speed data packet access (HSDPA) and three bandwidth profiles: 1.75 MHz, 3.5 MHz, and 7 MHz, each incorporating the IEEE 802.16d worldwide interoperability for microwave access (WiMAX) standard. This paper examines the relationship between the signal-to-noise ratio (SNR) characteristics of a digital IF transceiver with an under-sampling scheme and the sampling jitter effect on a multichannel orthogonal frequency-division multiplexing (OFDM) signal. The simulation and experimental results show that the SNR of the OFDM system with narrower band profiles is more susceptible to sampling clock jitter than systems with relatively wider band profiles. Further, for systems with a comparable bandwidth, HSDPA outperforms WiMAX, for example, a 5 dB error vector magnitude improvement at 15 picoseconds time jitter for a bandwidth of WiMAX 3.5 MHz profile.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.448-453
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• 2005

For under-water communication system, due to limit of bandwidth and reflect of under-water wave, it is difficult to implement high-reliability high-speed digital communication system. To apply high-reliability and high-speed communication system for under-water system, the efficient combine the channel design with the use of multiple transmit and/or receive antennas. Therefore this paper analyze the space time coded system for under-water communication environment.

• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.57-64
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• 2022

In this paper, the definition and overview of digital health care that has emerged recently, core technology, and We would like to propose a plan to establish a next-generation information protection system that can protect digital healthcare devices and data from cyber attacks. Various vulnerabilities exist for digital healthcare devices and data, and cyber attacks are possible for those vulnerabilities. Through an attack on digital health care devices and information and communication networks, it can directly adversely affect human life and health, Since digital healthcare data contains sensitive and personal information, it is essential to safely protect it from cyber attacks. In the case of this proposal, for continuous safe management of data and cyber attacks on equipment and communication networks for digital health devices, It is expected to be able to respond more effectively and continuously through the establishment of the next-generation information protection system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1-2
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• 2008

Korea Electric Power Research Institute has carried out verification of communication conformance on IEC 61850 based IEDs related to power IT project "Development of Prototype for Advanced Substation Automation System based on the Digital Control Technology". Owing to IEC 61850 international standard and digital substation automation system, IED testing process should be changed from the conventional way to the new way described in the paper. This paper describes IED testing procedures based on substation automation system using UML.

• Journal of Korea Multimedia Society
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• v.24 no.12
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• pp.1682-1692
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• 2021

Digital Twin, one of the core technologies of the Fourth Industrial Revolution, is attracting attention as a very suitable technology for disaster monitoring such as fires and earthquakes. In this paper, we implement a system equipped with UWB RTLS(Ultra-Wideband Real Time Location System), real-time remote control, and video streaming, which are element technologies for disaster monitoring digital twin. Since the proposed system structure is based on a cloud server, the actual location of the UWB indoor positioning-based client is transmitted to the user device in real time and stored on the cloud server for statistical and data analysis. In addition, we demonstrate through experiments that outliers occurs when the value of RSSI(Received Signal Strength Indicator) decreases due to communication collisions between UWB Tags, and propose an RSSI outlier correction algorithm to solve this problem.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.9
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• pp.495-503
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• 2000

In this paper we propose a design procedure of loop-shaping two-degree-of-freedom H$\infty$ digital controller for sampled-data system. We extend the continuous time loop-shaping two-degree-of-freedom H$\infty$ control problem to sampled-data system. The configuration of generalized plant is modified for sampled-data system. And then using continuous lifting we obtain the digital controller. In the final stage of loop-shaping procedure the problem of absorbing weighting functions is discussed. We summarize this study to the design procedure and illustrate the application for an inverted pendulum on the cart.