디지털 오디오 방송을 위한 터보 부호화된 OFDM

김한종,Kim, Han-Jong 대한전자공학회 2001 電子工學會論文誌-TC (Telecommunications) Vol.38 No.11

본 논문에서는 펑쳐드 콘볼루션 부호기와 연관정 비터비 복호기를 사용하는 기존의 COFDM DAB 시스템에서 부호 율이 1/4인 모체부호로부터 부호화 된 4비트 중 처음 한 비트는 펑쳐링되지 않고 언제나 전송된다는 사실에 근거하여 기존 COFDM DAB 시스템에서 정의된 펑쳐링 절차를 수정함이 없이 터보 부호를 적용한 TCOFDM(Turbo Coded OFDM) DAB 시스템 모델을 제안한다. COFDM DAB 시스템에 터보 부호기를 적용하기 위해 유효 자유거리가 최대인 터보 부호기를 설계하여, 기존의 펑쳐링 과정을 수정함이 없이 터보 부호기로 대체하기 위해 새로운 펑쳐링 과정을 정의한다. 또한 제안된 터보 부호기에 대한 복호기 구조를 제안하고 DAB 시스템에서 정의된 네 가지 전송모드 중에서 단일 주파수망(SFN) 방송 시스템 구성에 유리한 전송모드 I과 위성방송에 적합한 전송모드 III에 대해서 기존의 COFDM DAB 시스템과 제안된 TCOFDM DAB 시스템의 성능을 주파수 선택적 라이시안 페이딩 채널 및 주파수 선택적 레일레이 페이딩 채널 환경에서 컴퓨터 시뮬레이션을 통해 비교, 분석하여본다. The Pan-European Digital Audio Broadcasting(DAH) system's performance is characterized and improved with the aid of turbo codec. From the fact that the first bit among the four coded bits at the RCPC coding defined in the Eureka 147 DAD system is not. punctured and always transmitted, this paper proposes a new turbo coded DAB system model that replaces the existing RCPC codec by a turbo codec without modifying the puncturing procedure and puncturing vectors defined in the standard DAB system for compatibility. The performance of a new system is compared to that of the conventional system under the Rician fading channel and the Rayleigh fading channel in conjunction with DAD transmission mode I and III suitable for the terrestrial single frequency network and satellite broadcasting.

Propose and Performance Analysis of Turbo Coded New T-DMB System

김한종,Kim, Hanjong The Society of Digital Policy and Management 2014 디지털융복합연구 Vol.12 No.3

Eureka 147 디지털오디오방송(DAB) 시스템은 CD 품질의 오디오 전송을 위하여 유럽에서 개발되었으나 한국에서는 이러한 DAB 시스템을 기반으로 하여 오디오뿐 만 아니라 비디오 신호도 전송할 목적으로 지상파 디지털 멀티미디어방송(T-DMB) 시스템을 개발하였다. 이러한 T-DMB 시스템의 성능 향상을 목적으로 본 논문에서는 양립성을 위해 기존 T-DMB 시스템 표준안에 정의된 펑쳐링 절차와 평처링 벡터를 이용하면서 터보 부호가 적용된 2가지 형태의 새로운 터보부호화된 T-DMB 시스템 모델을 제시한다. 첫 번째 모델 (Type 1)은 기존의 RS 코드, 콘볼류션 인터리빙, RCPC 코드를 터보코드로 대체시킨 것이며 두 번째 모델(Type 2)은 기존 RCPC 만을 터보부호로 대체시킨 모델이다. 시뮬레이션 결과 제안된 모델은 단지 2회 반복만으로도 상당한 성능 향상을 얻을 수 있음을 알 수 있었으며 또한 두 번째 모델은 첫 번째 모델에 비해 약간 우수한 성능을 보이고 있다. The DAB system was designed to provide CD quality audio and data services for fixed, portable and mobile applications with the required BER below $10^{-4}$. However for the T-DMB system with the video service of MPEG-4 stream, BER should go down $10^{-8}$ by adding FEC blocks which consist of the Reed-Solomon (RS) encoder/decoder and convolutional interleaver/deinterleaver. In this paper we propose two types of turbo coded T-DMB system without altering the puncturing procedure and puncturing vectors defined in the standard T-DMB system for compatibility. One(Type 1) can replace the existing RS code, convolutional interleaver and RCPC code by a turbo code and the other one (Type 2) can substitute the existing RCPC code by a turbo code. Simulation results show that two new turbo coded systems are able to yield considerable performance gain after just 2 iterations. Type 2 system is better than type 1 but the amount of performance improvement is small.

자동 초음파 검사를 위한 결함 영상 처리 시스템의 설계 및 구현

김한종,박종훈,김철원,Kim, Han-Jong,Park, Jong-Hoon,Kim, Chul-Won 한국정보통신학회 2010 한국정보통신학회논문지 Vol.14 No.1

용접부 내에 존재하는 결함의 형태, 위치, 크기 등의 정보를 정량적으로 파악하기 위하여 초음파 탐상 검사가 많이 활용되는데, 최근 들어 용접부의 결함 탐상을 위해, 검사과정을 기계적 스캐너로 자동화한 자동 초음파 탐상 시스템이 많은 산업 분야에서 활용되고 있고, 특히 배관 용접부의 건전성 평가를 위한 비파괴안전진단에서 그 활용 폭이 커지고 있다. 본 논문에서는 배관 용접부의 자동 초음파 검사를 위한 알고리즘 구현과 결함 영상을 보정하여 주는 결함영상 처리 시스템을 설계 및 구현하였다. 적용된 기법으로는 초음파 A-Scan 압축 알고리즘, Synthetic Aperture Focusing 알고리즘, 결함영상증폭 알고리즘과 이와 관련된 소프트웨어 설계 및 구현에 대하여 논한다. In this study, an automated ultrasonic testing system and post signal and image processing techniques are developed in order to construct ultrasonic flaw images in weldments. Image processing algorithms are built into the flaw image processing system for the automated ultrasonic testing system. The developed signal and image analysis algorithms addressed in this study include an A-Scan data compression algorithm, ultrasonic image amplification algorithm and B-scan flaw image correction algorithm(SAFT). This flaw image processing system for the automated ultrasonic testing system can be applied to various inspection fields.

전동기 과전압 억제용 OUTPUT REACTOR의 최적 설계

김한종(Han-Jong Kim),이근호(Geun-Ho Lee),장철호(Cheol-Ho Jang),이제필(Jea-Pil Lee) 전력전자학회 1999 전력전자학술대회 논문집 Vol.1999 No.7

In this paper, the cost-effective design of output reactor which IS used to suppress the over-voltage at the motor terminal in the Adjustable Speed Drives(ASD) application is proposed In the elevator drive system, the power cable length is relatively shorter than other ASD applications and then the over-voltage at the motor terminal depends on the frequency characteristics of the output reactor at the over-voltage operating frequency The over-voltage suppression mechanism of output reactor m ASD application is analyzed and the dominant parameters of output reactor for the over-voltage suppression are extracted Using these parameters as the design values and considering the high frequency characteristics of Iron core In the reactor, a new cost-effective structure of output reactor is proposed Experimental results of the conventional reactor and the proposed reactor with a 15kW induction motor are given to verify the proposed scheme.

항공기용 열교환기 매니폴드의 위상최적화 설계

김한종(Hanjong Kim),허민혁(Minhyuk Heo),한창완(Changwan Han),박성훈(Seonghun Park) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

The heat exchanger manifold of the aircraft serves to evenly distribute the fluid coming in through the inlet and then out to the heat transfer unit. To meet this requirement, the manifold must be designed to be lightweight and to withstand high internal pressures. Therefore, this study aims at minimizing the weight of the heat exchanger manifold through topology optimization. To optimize the topology, the initial design space was first determined considering the inner surface of the existing manifold model with the outer surface shaped by a solid cube. A finite element model of the initial design space was created in ANSYS Workbench. Upper side of the manifold was then fixed to represent the welding joints of the manifold and an inner pressure of 5.5 MPa was applied on the inner surface of the manifold as boundary conditions. Six case studies were performed with different weight targets to obtain a minimized shape with maximum stiffness at a given volume, resulting in the key structure of the manifold being identified. By observing the change in manifold structure due to weight reduction, we were able to select the key structure to distribute the load on the manifold. Currently, we further simply the shape of the topology optimised manifold reflecting the key structure identified in the case study results and we also plan to use the 3D metal printing process to manufacture the manifold optimised and simplified.

증권집단소송제도의 활성화방안에 관한 연구

김한종 ( Han Jong Kim ) 홍익대학교 법학연구소 2009 홍익법학 Vol.10 No.3

여성기업 지원법제에 대한 입법론적 개선방안

김한종 ( Han Jong Kim ) 홍익대학교 법학연구소 2011 홍익법학 Vol.12 No.3

사물인터넷(IoT)을 위한 무선통신 교육장비 개발

김한종 ( Han-jong Kim ) 한국실천공학교육학회 2021 실천공학교육논문지 Vol.13 No.2

무선통신은 사물인터넷(IoT)을 구성하는 핵심기술이나 사물인터넷에 활용되고 있는 다양한 무선통신 기술들을 실습을 통해 학습할 수 있는 적합한 교육장비가 존재하지 않는다. 본 논문에서는 다양한 IoT 무선통신 실습을 수행해 볼 수 있는 첨단교육훈련장비 개발을 다룬다. 다양한 센서들을 제어하기 위한 디바이스로 아두이노 메가 보드를 사용하며 센싱한 데이터를 무선으로 송수신하기 위한 IoT 무선네트워크 기술로 WPAN 기술 중 RFID/NFC, Bluetooth 무선네트워크 기술, WLAN 기술 중 WiFi기술을 사용하며 WWAN 기술 중 LoRa와 2.4GHz 무선 트랜시버를 사용한다. 그 밖에 GPS, 적외선통신, I2C 통신, SPI 통신에 대하여 실습을 통해 다양한 IoT 무선통신 기술들을 학습할 수 있도록 구성하였다. 또한 본 논문에서 개발한 교육장비는 2개의 디바이스를 장착하고 있어 장비내에서 무선네트워크 기술에 대한 송수신 실험을 수행해 볼 수 있도록 설계하였다. Wireless communication is a core technology constituting the Internet of Things (IoT), but there is no suitable educational equipment to learn various wireless communication technologies used in the Internet of Things through practice. This paper deals with the development of advanced education and training equipment that can perform various IoT wireless communication practices. It uses an Arduino mega board as a device to control various sensors. As wireless network technologies to send and receive the sensing date wirelessly, it makes use of RFID/NFC and Bluetooth among WPAN technologies, WiFi among WLAN technologies and LoRa and 2.4GHz wireless transceiver among WWAN technologies. In addition, GPS, infrared communication, I2C communication, and SPI communication are organized so that various IoT wireless communication technologies can be learned through practice. In addition, since the educational equipment developed in this paper is equipped with two devices, it is designed to perform transmission and reception experiments for wireless network technology within the equipment.

상법상 주식회사의 사외이사제도에 관한 연구 -상장회사 사외이사의 독립성 제고방안을 중심으로-

김한종 ( Han Jong Kim ) 홍익대학교 법학연구소 2016 홍익법학 Vol.17 No.1

Korea’s outside director system was introduced in 1998 and 18 years have passed since. But the evaluation of the outside director system’s establishment and system management is mostly negative. Many causes are pointed out as the problem of the current outside director system’s critical evaluation. Most of all, the lack of independence of the outside director can be seen as the core problem. Therefore, securing maximum independence of the outside director will be the shortcut to solve the problem of the outside director system and to maximize the efficiency of the system. The independence of outside director should be secured primarily from the electing stage. First of all, an independent person should be nominated as the outside director candidate, and electing process should have minimum influence from controlling shareholders or executives and be as objective and fair as it can be. And after being elected as the outside director, independent environment should be provided for conduction of business. Not only should the outside director easily acquire company information like financial documents, but also legal environment should be prepared for the company to actively provide ample information for the outside director. Also, the outside director can independently perform one’s duty as long as the director is free from layoff problem and position of the outside director is stably maintained. The perspective of the independence of the outside director is the most essential premise for securing effectiveness of the outside director system. However, improving outside director’s independence can not solve all problems. Therefore, effort is needed to grasp the outside director system generally and provide improvement plan to raise the effectiveness of the system and to establish it successfully.

역사교육 내용선정 기준 - ‘의미 있는 역사’의 개념 탐색 -

김한종 ( Kim Han-jong ) 역사교육학회 2021 역사교육논집 Vol.77 No.-

This study explored the concept of “significant” history as the criterion for selecting content for school history. “Significant” histories are facts that have had a far-reaching or profound impact on historical actors and the society in those times based on historical discipline. History that is “significant” to students is history that is relevant to their lives. What is relevant to the lives of students is not only experienced or directly experienced, but also includes things that are the subject of thought and the basis of practice. Rather than past knowledge, teachers consider historical facts that can be applied practically to understand the present day and solve the problems of modern society as significant history. This concept of “significant history” gives the following implications for constructing the contents of history and national curriculum. First, in the syllabus organization of the curriculum, it is necessary to approach the problem of “what and how” to teach rather than only “what” to teach. And “how” refers to a viewpoint and approach to viewing historical facts rather than teaching and learning techniques. Second, we need to teach students “what is significant to them” rather than “what they can understand”. “Significant” history is one in which historical facts themselves are important, experienced or embodied in the lives of students, and connected to pupil’s social practices. Third, we need to allow students to experience history. Experiencing history implies experimental historical thinking instead of repeating past human behaviors.