• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(3)
• /
• pp.47-50
• /
• 2000

Recently many efforts on the development of automatic processing system for delivery sequence sorting have been performed in ETRI , which requires the use of postal 4-state bar code system to encode delivery points. The 4-state bar code called postal 4-state bar code for high speed processing that has been specifically designed for information processing of logistics and automatic processing of the mail items. This paper describes a method of Reed-Solomon encoding for creating error correction codeword of 4-state bar code.

• 한국산업정보학회논문지
• /
• 제11권4호
• /
• pp.112-120
• /
• 2006

다중 반송파 기술과 CDMA 기술이 결합된 MC-CDMA 시스템은 주파수 선택적 페이딩에 의한 신호감쇄를 완화시키면서 높은 전송률에 대한 요구를 만족시킬 수 있는 전송방식이다. 본 논문에서는 전송률이 서로 다른 다양한 서비스들을 지원하기 위한 새로운 비동기 MC-CDMA 시스템을 제안한다. 제안한 시스템에서는 W-CDMA 하향링크에 사용되는 채널화 코드인 orthogonal variable spreding factor(OVSF) 코드의 생성특성을 이용하여 발생된 OVSF 코드를 다중전송률 MC-CDMA의 확산부호로 사용한다. 사용자의 전송률에 따라 길이가 다른 OVSF 코드를 확산부호로 사용하며 OVSF 코드 트리에서 같은 가지에 속한 코드들을 사용하는 사용자들을 모아 그룹화를 한다. 제안된 다중 전송률 비동기 MC-CDMA 시스템을 위한 모델을 제시하길 이에 따른 시스템 성능분석을 행한다. 제안된 시스템과 직교부호를 확산부호로 사용하는 단일 전송률 MC-CDMA시스템의 성능과 비교 분석한다.

• 컴퓨터교육학회논문지
• /
• 제5권4호
• /
• pp.123-133
• /
• 2002

이 논문에서는 교육용 컨텐츠 개발 방법인 EduCODE를 제안하고 이를 지원하는 시스템을 설계 및 구현하였다. EduCODE는 영역 모델, 항해 모델, 추상 인터페이스 모델, 애셋 모델 등 4개의 모델로 구성하였으며, 컨텐츠의 구성을 다이어그램으로 표현할 수 있는 표기법을 제안하였다. EduCODE를 지원하기 위한 자동화 시스템은 저작 모듈과 실행 모듈로 구성되어 있으며, 저작 모듈에서 생성된 각 명세서는 국제적인 교육용 컨텐츠 표준인 ADL SCORM XML 코드를 자동으로 생성하고 실행 모듈과 웹 서버를 통해 서비스된다.

• Journal of electromagnetic engineering and science
• /
• 제7권1호
• /
• pp.1-6
• /
• 2007

Recently, Mc(Multi-code) modulation/demodulation(modem) technique has been explored for high speed data transmission in wireless environment. The conventional Mc modem generates some side effects such as allocating Walsh codes, which motivates to propose a novel Mc modem method with sub-code. Our proposed system should expanded the size of sub-code to provide high-rate data transmission, which also affect adversely to the performance of the system with high PAPR(Peak to Average Power Ratio). Thus, in this paper, we propose a novel pre-coded Multi-Dimensional HCOC(High Capacity Orthogonal Code) Mc modem technique to reduce the high PAPR, which enables the performance improvement. This proposed system can be easily designed by concatenating HCOC Mc modem with the generic Mc modem. The pre-coding technique that is used in this paper is CAC(Constant Amplitude Coding), that helps the system maintain the constant transmission power and reduce the maximum transmission power.

• 방송공학회논문지
• /
• 제24권7호
• /
• pp.1221-1227
• /
• 2019

This paper describes a low-density parity-check (LDPC) coded index modulated orthogonal frequency division multiplexing with quasi-orthogonal sequence (IM-OFDM-QOS) and provides performance evaluations of the proposed system. By using QOS as the spreading code, IM-OFDM-QOS scheme can improve the reception performance than IM-OFDM-SS scheme for a given data rate. On the other hand, LDPC code is widely used to the latest wireless communication systems as forward error correction (FEC) scheme and has Shannon-limit approaching performance. Therefore, by applying LDPC code to IM-OFDM-QOS system as FEC scheme, the reception performance can be further improved. Simulation results show that significant signal-to-noise ratio (SNR) gains can be obtained for LDPC coded IM-OFDM-QOS system compared to the LDPC coded IM-OFDM-SS system and the SNR gain increases with the higher code rate.

• 한국통신학회논문지
• /
• 제32권4C호
• /
• pp.370-378
• /
• 2007

The most appropriate low density parity check (LDPC) code for hybrid automatic repeat request (HARQ) system suitable for future multimedia communication systems is presented in this paper. HARQ system with punctured LDPC code is investigated at first. And two transmission schemes with parallel concatenated LDPC code are also presented and their performances are analyzed according to the various values of mean column weight (MCW). As a result, the parallel concatenated LDPC code with the diversity effect of information bit is considered to be more appropriate for HARQ system considering the throughput as well as error performance.

• International Journal of Advanced Culture Technology
• /
• 제8권2호
• /
• pp.289-296
• /
• 2020

Software copyright are written in text form of documents and stored as files, so it is easy to expose on an illegal copyright. The IOT framework configuration and service environment are also evaluated in software structure and revealed to replication environments. Illegal copyright can be easily created by intelligently modifying the program code in the framework system. This paper deals with similarity comparison to determine the suspicion of illegal copying. In general, original source code should be provided for similarity comparison on both. However, recently, the suspected developer have refused to provide the source code, and comparative evaluation are performed only with executable code. This study dealt with how to analyze the similarity with the execution code and the circuit configuration and interface state of the system without the original source code. In this paper, we propose a method of analyzing the data of the object without source code and verifying the similarity comparison result through evaluation examples.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 추계종합학술대회 논문집
• /
• pp.17-20
• /
• 1999

In this Paper, we discuss reducing the number of orthogonal code in Multi-Code CDMA (MC-CDMA) system. MC-CDMA system is highlighted for multi-media communication services, but conventional MC-CDMA(CMC-CDMA) system are needed many more orthogonal codes compared to traditional direct sequence CDMA(DS-CDMA) systems. in this paper, we propose the system which can reduce the number of orthogonal codes using sub-orthogonal code(SOC) technique. We certificate that the performance of the proposed system shows the almost same result under gaussian noise environment as compared to CMC-CDMA system through Monte-Curio computer simulation method.

• 한국통신학회논문지
• /
• 제25권3A호
• /
• pp.391-398
• /
• 2000

In this paper, MRC(Maximum Ratio Combine) diversity, (23, 12) Golay code, (7, 5) Reed-Solomon code, and (3, 1) majority selection code are employed to improve the performance of DS/CDMA BRSK in Nakagami fading channel. and MRC diversity combined with other coding techniques is suggested, with which, the performance of DS/CDMA BRSK is compared and analyzed. Also, system required Eb/N0 to meet BER=10-5 for multi user data communication is obtained according to each techniques. From the results, when each techniques is employed to DS/CDMA BRSK system. coding employed system shows better performance than diversity employed system. Especially, Golay code shows better performance than oter codes. also MRC diversity is employed, the number of multiple access user to meet data communication requirement of BER=10-5 can accomodate up to 8 users. and when each code is employed, Golay code, majority selection code, and Reed-Solomon code shows the capacity of 14, 12, and 10 user respectively. But MRC diversity combined with coding techniques can reduce restriction of multiple access user. However, it is desirable these combined technique are employed according to service types and requirements provided.

• 해양환경안전학회지
• /
• 제9권1호
• /
• pp.33-40
• /
• 2003

이 논문은 해상보안체제의 도입방향을 연구하기 위한 것이다. 최근 2, 3년 사이에, 몇 편의 논문이 ISPS Code에 관한 연구를 다루고 있다. 2002년 12월 런던에서 개최된 해상보안에 관한 외교회의에서는 해상보안의 강화를 위하여 1974년 해상인명안전협약의 새로운 규정 및 본 보안규칙을 채택하였다. 이러한 새로운 요건들을 통하여 선박과 항만이 서로 협력하는 가운데 해상수송 분야의 보안을 위협하는 행위들을 감지하고 막을 있는 국제적인 체제가 형성되어질 수 있도록 하였다. 따라서 이 논문의 목적은 ISPS Code를 이해하고 해상보안체제의 도입방향을 제시하는 데 있다.