• 대한토목학회논문집
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• 제28권4B호
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• pp.421-428
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• 2008

최근 들어 우리나라 전해역에 걸쳐 발생하고 있는 침식은 사회적인 문제가 되어왔다. 하지만, 해안구조물에 의한 기존의 방법으로 해안선을 보호하는 것이 "파랑장에 친화적인가?"라는 관점에서 개선의 여지가 있다. 새로운 형식의 철재형 이안제는 권혁민 등(2007)에 의해 제안되었다. 본 형식은 다수의 파일과 상부에 파랑진행방향과 수평으로 설치된 소파장치로 구성되어 있다. 본 형식은 해수유통원활, 대수심 축조수월, 공기단축 등의 장점이 있다. 본 연구는 소파제로서 철재형 이안제의 상부에 거치가 가능한 이열 조합판의 투과율을 실험적으로 평가했다. 일방향 불규칙파 시스템에 의한 모형실험을 통하여 반사율, 소파율, 투과율에 관하여 분석했다. 실험결과, 파형경사가 클수록 그리고 조합판의 폭-파장비가 클수록 투과율이 작아짐을 보였다. 본 연구는 이열 소파판 조합에 대하여 투과율 산정을 위한 직선식을 제안했다.

• 전자공학회논문지
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• 제50권7호
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• pp.68-75
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• 2013

최근 이동 ad hoc 네트워크에 적합한 ID기반 암호시스템의 구현을 위한 Weil, Tate, Ate와 같은 페어링 연산 기법에서는 밀러 알고리듬이 사용된다. 페어링 연산의 활용 영역이 넓어짐에 따라 다양한 오류 공격이 제안되고 있으며, 그중 카운터 오류 공격이 가장 강력한 위협으로 여겨진다. 따라서 본 연구에서는 카운터 오류 공격에 대한 새로운 대응책을 제안한다. 제안 기법은 중간 값을 저장하는 위치를 랜덤하게 함으로써 오류에 의한 변형 가능성을 줄이고, if 구문에 의한 부채널 특성을 제거하여 오류 공격의 시도 자체를 어렵게 한다.

• 한국통신학회논문지
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• 제30권7A호
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• pp.587-596
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• 2005

본 논문에서는 사용자를 주파수로 구분하고 데이터를 주파수 영역 확산으로 다중화하는 OFDMA/CDM 기반 셀룰라 시스템을 제안하다. 셀 구분을 위해 랜덤코드를 이용하며, 시스템 성능 향상을 위하여 전치등화를 적용한다. 송신전력이 제한된 다중셀 환경에 적합한 전치등화 방법과 효율적인 전력할당 방식을 제안한다. 다중셀 환경에서 각 등화방법 및 전력할당 방식에 따른 성능을 분석하곤 특히 셀 중심으로부터의 거리에 따른 성능 변화, 다중화 데이터 개수에 따른 성능 분석을 통괘 다중셀 환검 적용 타당성을 분석한다. 끝으로 시간지연에 따른 성능저하를 전치와 후치 등화를 모두 사용한 전/후치등화를 적용하여 줄일 수 있음을 보인다.

• 한국통신학회논문지
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• 제29권1C호
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• pp.9-17
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• 2004

본 논문에서는 일종의 멀티코드 시스템인 Binary CDMA의 성능을 향상시키기 위해 상관도 값을 평활화하는 방법을 제안한다. DS-CDMA 방식과는 달리, Binary CDMA 에서는 멀티레벨 신호를 이진 클리핑하여 전송하므로 선형성이 떨어지는 전력증폭기를 사용해도 무방하다. 그러나, 전송신호가 이진 클리핑되는 과정에서 각 채널사이의 직교성이 감소하여 수신부에서의 채널별 상관도 값은 랜덤해지며, 가장 작은 상관도 값을 갖는 채널에 의해 시스템의 평균 BER이 결정된다. 본 연구에서는 수신부 상관도 값이 불균형한 분포를 갖지 않고, 전 채널에 대해 고르게 분포하게 하는 상관도 평활화 방법을 적용하여 시스템의 평균 BER을 개선하였다. 여러 종류의 확산코드를 이용하여 실험한 결과, BER은 낮아지고 가용 채널의 수는 증가하였다.

• 한국통신학회논문지
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• 제35권7A호
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• pp.682-687
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• 2010

The IEEE 802.15.4a specification targets the low-rate (LR) Impulse-radio (IR) ultra-wideband (UWB) system which is now widely applied in the WPANs considering rather short distance communications with low complexity and power consumption. The physical (PHY) layer uses concatenated coding with mixed binary phase-shift keying and binary pulse-position modulation (BPSK-BPPM), and direct sequence spreading with time hopping in order that both coherent and non-coherent receiver architectures are supported. In this paper, the performances of multiple access schemes compliant with IEEE 802.15.4a specification are investigated with energy detection receiver, which allow avoiding the complex channel estimation needed by a coherent receiver. However, the performance of energy detection receiver is severely degraded by multi-user interference (MUI), which largely diminishes one of the most fascinating advantages of UWB, namely robustness to MUI as well as the possibility to allow parallel transmissions. So as to improve the performance of multiple access schemes, we propose to apply the novel TH sequences as well as to increase the number of TH positions. The simulation results show that our novel multiple access schemes significantly improve the performance against MUI.

• 한국통신학회논문지
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• 제30권7C호
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• pp.666-674
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• 2005

이동국에서 받은 되먹임 정보를 바탕으로 하는 차단 적응 전송 기법을 쓸 때, 여러 반송파 부호분할 다중접속/주파수분할 다중방식의(multi carrier code division multiple access/frequency division multiplexing: MC CDMA/FDM 내림 연결 성능을 알아본다. 셀이 하나일 때 직교 서명수열을 쓰면, 제안한 기법은 여러 반송파 직접 수연 부호분할 다중접속(direct sequence/code division multiple access: MC DS/CDMA) 방식과 적응 주파수 뜀/직접 수열(frequency hopping/direct sequence: FH/DS) 방식보다 성능이 더 좋다. 셀이 여럿일 때에도 직교 서명수열이나 확률 서명수열을 쓰면, 제안한 기법이 적응 주파수 뜀/직접 수열 방식보다 성능이 더 좋다.

• 한국IT서비스학회지
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• 제15권4호
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• pp.1-24
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• 2016

With the innovation of information technology, non-face-to-face robo advisor with high accessibility and convenience is spreading. The current robot advisor recommends appropriate investment products after understanding the investment propensity based on the structured data entered directly or indirectly by individuals. However, it is an inconvenient and obtrusive way for financial consumers to inquire or input their own subjective propensity to invest. Hence, this study proposes a way to deduce the propensity to invest in unstructured data that customers voluntarily exposed during consultation or online. Since prediction performance based on unstructured document differs according to the characteristics of text, in this study, classification algorithm optimized for the characteristic of text left by financial consumers is selected by performing prediction performance evaluation of various learning discrimination algorithms and proposed an intelligent method that automatically recommends investment products. User tests were given to MBA students. After showing the recommended investment and list of investment products, satisfaction was asked. Financial consumers' satisfaction was measured by dividing them into investment propensity and recommendation goods. The results suggest that the users high satisfaction with investment products recommended by the method proposed in this paper. The results showed that it can be applies to non-face-to-face robo advisor.

• International Journal of Computer Science & Network Security
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• 제21권7호
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• pp.133-149
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• 2021

The purpose of this study is to explore the role of information systems in the implementation of knowledge management, at King Abdul-Aziz University (KAU) in Jeddah, by highlighting the importance of information systems and their implementation of the knowledge processes. The researcher used the case-study method to explore the importance of information systems in supporting the implementation of knowledge management at the university. Moreover, the study has used the questionnaire as a tool for collecting information and obtaining feedbacks from the administrators at the university, and a random sample was chosen to identify the study community. The study resulted that there is a statistical indication of the importance and degree of the use of electronic systems in the university by the administrators. The study sample members believe that the university is keen to provide information systems, where systems analyze data and convert them into knowledge information that benefits the senior management at the university. Members of the study sample emphasize the importance of electronic information systems at the university, which in turn saves time and effort in extracting information, reports, statistics and providing them easily to senior management. The study also concluded with some recommendations, such as emphasizing the importance of knowledge management as one of its top priorities, spreading the knowledge culture, instilling a vision of knowledge among individuals, and emphasizing the importance of information systems.

• 한국IT서비스학회지
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• 제18권1호
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• pp.219-234
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• 2019

Fake news threaten democratic elections and causes social conflicts, resulting in major damage. However, the concept of fake news is hard to define, as there is a saying, "News is not fake, fake is not news." Fake news, however, has irreversible characteristics that can not be recovered or reversed completely through post-punishment of economic and political benefits. It is also rapidly spreading in the early days. Therefore, it is very important to preemptively detect these types of articles and prevent their blind proliferation. The existing countermeasures are focused on reporting fake news, raising the level of punishment, and the media & academia to determine the authenticity of the news. Researchers are also trying to determine the authenticity by analyzing its contents. Apart from the contents of fake news, determining the behavioral characteristics of the promoters and its qualities can help identify the possibility of having fake news in advance. The online community has a fake news interception and response tradition through its long-standing community-based activities. As a result, I attempted to model the fake news by analyzing the affirmation-denial analysis and posting behavior by securing the web board crawl of the 'M community' bulletin board during the 2017 Korean presidential election period. Random forest algorithm deemed significant. The results of this research will help counteract fake news and focus on preemptive blocking through behavioral analysis rather than post-judgment after semantic analysis.

• International Journal of Knowledge Content Development & Technology
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• 제11권4호
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• pp.35-51
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• 2021

This study measured the effects of fake news and propaganda on managing information on COVID-19 among the Nigerian citizenry. This study examined sources of information on COVID-19 available to the people, evaluated reasons behind spreading fake news, examined how fake news has affected the spread of COVID-19 pandemic in Nigeria, established the consequences of fake news on managing COVID-19 pandemic and as well identified ways to contain fake news at a time like this in Nigeria.It is a survey with a sample size of 375 participants selected using simple random technique. Instrument of data gathering was questionnaire widely distributed in the six geo-political zones of Nigeria using Survey monkey. Data was analysed using frequencies, counts and percentages, tables and charts. Findings revealed that people rely more on radio, television, and social media for information on COVID-19. Fake news is spread by people mostly for political reasons and intention to cause panic. In Nigeria, fake news has led to disbelief of the existence of the virus thereby leading to violation of precautionary measures among the citizenry and lack of trust in the government. Concerted effort on the part of the government is required to give public enlightenment on the danger of fake news. Also, directorate of anti-fake news should be established to censor and reprimand sources of fake news. People should always check source of information to confirm its credibility and be weary of sharing unconfirmed information especially on the social media.