• Journal of Electrical Engineering and Technology
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• 제6권6호
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• pp.769-775
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• 2011

Custom power devices such as dynamic voltage restorer (DVR) and DSTATCOM are used to improve the power quality in distribution systems. These devices require real power to compensate the deep voltage sag during sufficient time. An interline DVR (IDVR) consists of several DVRs in different feeders. In this paper, a neural network is proposed to control the IDVR performance to achieve optimal mitigation of voltage sags, swell, and unbalance, as well as improvement of dynamic performance. Three multilayer perceptron neural networks are used to identify and regulate the dynamics of the voltage on sensitive load. A backpropagation algorithm trains this type of network. The proposed controller provides optimal mitigation of voltage dynamic. Simulation is carried out by MATLAB/Simulink, demonstrating that the proposed controller has fast response with lower total harmonic distortion.

• 한국멀티미디어학회논문지
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• 제24권5호
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• pp.701-708
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• 2021

As one of the most widely used technology in the world right now, Face recognition has already received widespread attention by all the researcher and institutes. It has been used in many fields such as safety protection, surveillance system, crime control and even in our ordinary life such as home security and so on. This technology with today's technology has advantages such as high connectivity and real time transformation. But we still need to improve its recognition rate, reaction time and also reduce impact of different environmental status to the whole system. So in this paper we proposed a face recognition system model with improved CNN which combining the characteristics of flat network and residual network, integrated learning, simplify network structure and enhance portability and also improve the recognition accuracy. We also used AR and ORL database to do the experiment and result shows higher recognition rate, efficiency and robustness for different image conditions.

• International Journal of Computer Science & Network Security
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• 제24권4호
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• pp.170-178
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• 2024

Through the growth of the fifth-generation networks and artificial intelligence technologies, new threats and challenges have appeared to wireless communication system, especially in cybersecurity. And IoT networks are gradually attractive stages for introduction of DDoS attacks due to integral frailer security and resource-constrained nature of IoT devices. This paper emphases on detecting DDoS attack in wireless networks by categorizing inward network packets on the transport layer as either "abnormal" or "normal" using the integration of machine learning algorithms knowledge-based system. In this paper, deep learning algorithms and CNN were autonomously trained for mitigating DDoS attacks. This paper lays importance on misuse based DDOS attacks which comprise TCP SYN-Flood and ICMP flood. The researcher uses CICIDS2017 and NSL-KDD dataset in training and testing the algorithms (model) while the experimentation phase. accuracy score is used to measure the classification performance of the four algorithms. the results display that the 99.93 performance is recorded.

• 한국IT서비스학회지
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• 제17권2호
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• pp.179-190
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• 2018

This study is about the influence of authors' centrality on research outcomes in a large-scale collaborative research network. Using the social network analysis method, five types of centralities were derived. Six research outcomes of individual researchers were also derived through bibliographic information of the social science field for the last 10 years. A multivariate regression analysis was conducted to examine the causal relationship between the centrality and research outcome, and the effect of centrality on research outcomes was found to be statistically significant. The result of this study shows that the revised citation and H-index significantly influenced the authors' centrality. This result can imply that the centrality of the researcher can expect a considerable influence of the thesis as well as a certain level of productivity. The meaning of this study is to analyze the effect of centrality on the research outcomes of the large-scale collaborative research network in the past decade, and is carefully to suggest a guideline in order to support new research information services for active researchers and the advancement of collaborative research. This study has its limitation for interpreting the diverse academic fields of the social sciences in a uniform way. In future study, it is necessary to conduct studies using various weighted indices for network centrality in order to measure the influence of research.

• 컴퓨터교육학회논문지
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• 제10권2호
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• pp.77-87
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• 2007

본 연구는 오프라인 수업을 온라인 토론이 보조하는 블렌디드 러닝 형태의 대학교 수업 상황에서 학습자의 적에 미치는 사회 연결망의 효과를 분석하기 위해 수행되었다. '사이버 학습 세미나' 과목을 수강하는 36명의 교육대학교 학생들을 대상으로 교우 연결망 중심도, 조언 연결망 중심도, 그리고 적대 연결망 중심도 등 세 가지 사회 연결망 변수들을 측정한 후, 이를 기말 과제 및 시험 점수 등 학습자 성과 변수들과의 상관관계를 분석하였다. 그 결과, 조언 연결망 중심도와 교우 연결망 중심도는 학습 성과와 정적 상관관계를 보이고 있었던 반면, 적대 연결망 중심도는 대부분분의 성과 변수들과 부적 상관관계를 보였다. 온라인 토론의 양과 질은 교우 연결망 중심도 및 조언 연결망 중심도와 높은 상관을 보였으며, 특히 그 질은 조언 연결망과 매우 높은 정적 상관관계를 나타내었다.

• 한국지반공학회논문집
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• 제18권3호
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• pp.113-125
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• 2002

지반의 지표침하를 예측하는 여러가지 경험식들이 있지만, 관련인자들을 동시에 고려하지 못함으로 인하여 불확실한 예측결과를 가져온다. 본 연구에서는 113개의 현장계측자료를 이용한 인공신경 망으로 조건에 따른 터널현장의 지표침하를 예측하였다. 지표침하 예측을 위한 현장자료의 입력양식을 제안하였으며, 인자학습을 통해 최적의 인공신경 망 모델을 구성하고 RSE의 개념을 통해 터널굴착으로 인한 지표침하에 영향을 미치는 주요인자들을 분석하였다. 본 연구에서 구성한 데이터베이스를 이용하여 인공신경 망 엔진을 학습하고 두 가지 현장자료를 통해 검증한 결과, 계측자료의 특성을 효과적으로 반영하는 것을 확인하였다.

• 디지털융복합연구
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• 제9권1호
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• pp.61-70
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• 2011

Ultimately, this research will focus on the activity traits of future customers in the convergence age. To accomplish that, firstly, researcher develop measures for assessing the convergence level of digital devices and digital services. Next, this will investigate the behavioral traits of people who use specific devices or services on the internet or mobile networks. This study proposed five convergence measures each for devices and services. For digital devices, measures such as converged functions, accessibility to network, portability, immediate communicability, and expandibility of functions were utilized. For digital measures such as scope of users, newness, social network level, ease-of use on mobile networks, and expandibility of information were used. We believe that the research results can provide insights for those wishing to explore the convergence level of devices and services and those developing high-level converged devices and digital services.

• 한국건축시공학회지
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• 제14권1호
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• pp.102-109
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• 2014

The purpose of this study is to analyze collaborative relationship between members of a building construction organization. For the analysis of collaborative relationship, this researcher collected data by conducting a questionnaire survey with members of three large building construction organizations for apartment housing. The analyzed contents of collaborative relationship were the 'frequency of communication between organizational members' and their 'reliability'. According to the analysis of communication network, construction managers had low frequency of communication, whereas those responsible for each area, like construction deputy managers, had high frequency of communication. It indicates that middle managers are at the center of communication related to construction work in construction organizations. According to the analysis of reliability network, construction managers showed highest reliability, and employees at the top level in an organizational map also showed high reliability. Since they generally have a lot of experience, are some older of age, and assume responsibility for work, they are considered to receive reliability from other organizational members. This study proved that it was possible to numerically express reliability of organizational members, which is an abstract concept, and analyze it. Therefore, it is expected that the analysis result will highly be likely to be used in the area of construction management.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.521-526
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• 2004

It is necessary to analyze the unsteady flow in the pipe network for the better operation and controls, but there are some problems in actual pipe network simulation, such as collecting a large amount of information in the field, operating highly upgraded computer system, and keeping a big storage device to run analysis program. The skeletonization method is used to cope with the problems in this paper. It is expected to reduce computation time, researcher's efforts, and costs for the analyzing the pipe network. The impact of individual pipe elements to the behavior of the water distribution system can be accounted in the process of skeletonization. However it is also important to study continuously about how to apply the skeletonization method for each of different cases, because inadequate uses may bring simulation to a false result. This paper introduces basic theories and skeletonizing examples in the actual pipe network in Dae-gu city.

• Journal of Information Science Theory and Practice
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• 제9권2호
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• pp.47-65
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• 2021

This study aims to identify specific topics, trends, and structural characteristics of scholarly communication research, based on 1,435 articles published from 1970 to 2018 in the Scopus database through Latent Dirichlet Allocation topic modeling, serial analysis, and network analysis. Topic modeling, time series analysis, and network analysis were used to analyze specific topics, trends, and structures, respectively. The results were summarized into three sets as follows. First, the specific topics of scholarly communication research were nineteen in number, including research resource management and research data, and their research proportion is even. Second, as a result of the time series analysis, there are three upward trending topics: Topic 6: Open Access Publishing, Topic 7: Green Open Access, Topic 19: Informal Communication, and two downward trending topics: Topic 11: Researcher Network and Topic 12: Electronic Journal. Third, the network analysis results indicated that high mean profile association topics were related to the institution, and topics with high triangle betweenness centrality, such as Topic 14: Research Resource Management, shared the citation context. Also, through cluster analysis using parallel nearest neighbor clustering, six clusters connected with different concepts were identified.