• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.3
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• pp.217-223
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• 2013

A digital retrodirective antenna system is easy to modify and upgrade because it can control the phase information of the output signal toward opposite direction to input signal without a priori knowledge of the arrival direction. Due to this advantage, it is possible to perform fast beam tracking. In this paper, a design digital retrosirective array antenna system according to the number of antenna array by using only one digital PLL which finds angle of delayed phase and we test BER performance of this system. When we transmit data at actual communication system, the data modulated onto carrier frequency in order to shift spectrum from base band to another band. So we simulate system considering carrier frequency according to the number of antenna array. As a result, carrier frequency has no impact on the performance.

• Digital Contents
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• no.4 s.119
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• pp.163-166
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• 2003

XML 저작툴은 유사한 특성을 갖고 있다. 이 툴들의 차이는 '아키텍처 측면'이다. 일부 툴은 강력한 서버가 지원하는 분산 환경에 적합하며, 다른 제품은 데스크탑용을 겨냥하고 있다. 설계 요소에 관계업이 XML 편집 툴은 구조에서 콘텐츠에 이르기까지 정보의 형성, 편집, 제작 및 재사용을 통제할 수 있다. XML 편집과 저작 기능을 조정하는 제품이 견고할수록 백-엔드 시스템을 갖춘 기업의 흥미를 끌 수 있다. Arbortext와 어도비 저작툴의 특징과 마이크로소프트가 경쟁자로 떠오르면서 업계의 변화를 따라가 보자.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1994.11a
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• pp.14-23
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• 1994

현재 운용되고 있는 대부분의 MHS는 송신자가 수신자에게 메세지를 전달하는 과정에서 적절한 보안서비스를 제공하지 못하고 있기 때문에 민감하거나 비밀스런 자료에 적합하지 못하며, 특히 여러 사람이 문서에 서명을 해야 하는데는 문제점을 안고 있다. 본 연구에서는 네트워크상에서 송신자의 신분인증과 메세지 인증 뿐만 아니라 전자문서를 일반문서와 같이 처리할 수 있는 디지털 다중서명을 MHS에서 구현할 수 있는 방안을 제시하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.8
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• pp.327-336
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• 2007

Lots of effort toward design optimizations have been paid for a cost-effective system design in various ways from a transistor level to RTL designs. In this paper, we propose a bit level optimization of an adder design for expanding its design space. For the bit-level optimization, a heterogeneous adder organization utilizing a mixture of carry propagation schemes is proposed to design a delay-area efficient adder which were not available in an ordinary design space. Then, we develop an optimization method based on Integer Linear Programming to search the expanded design space of the heterogeneous adder. The novelty of the Proposed architecture and optimization method is introducing a bit level reconstruction/recombination of IPs which have same functionality but different speed and area characteristics for producing more find-grained delay-area optimization.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1760-1766
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• 2009

Digital broadcasting and digital CATV and IPTV will continue in the competition, regardless of how the content of the program was broadcast over the Internet distribution and the damage of piracy is also growing. Excellent quality of the content of the digital CATV sales of DVD and high-density storage media because there is no difference in content and quality is the problem of illegal distribution. However, users can record and reuse program in the position of the guaranteed rights, and the purpose of training in fair and illegal recording and distribution needs to be separate from it. In this paper using a digital certificate recorded by the user and the process to ensure the purpose of illegal distribution of pharmaceutical distribution system design and implementation of the program was broadcast.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1564-1570
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• 2004

Recently, The Analog TV has been being replaced by digital TV. This dues to the advantage of digital TV that sends data as well as audio/video stream to the receiver. But there are no standards or rules for processing the data. So, most companies or developers process the data in separate methods. This absence of standards or rules for processing the data causes many confusions and waste of time, money, man power. This Thesis proposes the solution of the problem not based on standardized respect but methodological respect. This solution is using XML in producing and playing the broadcasted multimedia contents and data. We believe that this solution saves much man power, time, money and increase reusability of expensive broadcasting contents.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.643-650
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• 2013

This study was conducted to examine the effects of low-density exercise on physical and psychological function of the frail elderly. The research design was nonequivalent control group pretest-posttest design. Data were analyzed using descriptive statistics, x2-test, Mann-Whitney U test and Cronbach's ${\alpha}$ with SPSS/Win 17.0 program. There was a significant improvement in Lt. Grip strength(U=56.00, p<.000), Rt. Grip strength(U=40.00, p<.000), TUG(U=95.00, p<.022), Depression(U=94.00, p<.011) in the experimental group compared to the control group. The low-density exercise program showed the effects to improve the physical and psychological functions of the frail elderly. In recommendation, this exercise program could be utilized as a health promoting program for the frail elderly.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.72-79
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• 2016

In this paper, we propose a Service-adaptive Tactical Data Transmission Protocol (STTS) based on Satellite Communications with narrow bandwidth. STTS is designed to provide additional field for scalability and scheduler for reliability of transport stream protocol based on digital broadcasting standard, DVB-S and DVB-S2. It is also verified the effects of lost data packets with narrow bandwidth through the simulator by traffic model and re-transmission of critical data, and checked the design considerations based on STTS system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.5
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• pp.30-34
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• 1981

This paper deals with the testability evaluation method for the digital systems. This method uses two factors: the complexity and the accessibility. The complexity depends on the ratio in combinational and sequential circuits, number of input/output terminals, and the circuit count by using the gate input level method. The accessibility is how easily to handle the data from I/O terminals. The system testability has a normalized value. Thus, analyzing the testability evaluation, and redesigning the circuit to improve testability, the systems increase interests for the maintenance and have high reliability. Finally, in comparison with Stephenson and Grason's technique, this technique gives sufficiently accurate results for much less computation effort.

• Journal of Digital Convergence
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• v.13 no.6
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• pp.165-175
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• 2015

Methods to design programs which implement IT systems have been developed in various forms from flowchart to activity diagram of UML. However, program design tools and methods developed so far have not been efficient comparing to program coding tools and methods. In addition, Program design methods and tools developed until now have been difficult to support the bidirectional conversion between program design and coding, and the improvement of development productivity and maintainability. Therefore, in this study, we propose Convergence Development Method to enable working with wide bandwidth through fusing the program design and coding phase by using SOC and supporting tool named SETL which automatizes the convergence of design and coding. Thus, by using SETL, it is expected that the efficiency gap between the program design and coding phase is reduced, and development productivity and maintainability is increased. key words.