• Korean Journal of Optics and Photonics
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• v.3 no.3
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• pp.143-147
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• 1992

1)iscussed in this paper are the effects of phase modulation on the line spread functions (LSF) and MTFs of ;I binocular objective system. The binocular objective lens is made in Korea. It has rotationally symmetric aberrations. The LSFs and MTFs are measured experimentally. The phase modulation is carried out by applying phase retardation $\pi$ on the aperture. The area where the phase is not retarded presents a double annular type. The OTF curves of phase modulated aperture are compared with that of unmodulated aperture. The comparison shows that there is the aberration compensation effect in aberration loaded system. Therefore the performance of many optical system can be improved without any loss of light energy by properly modulating the phase on the aperture.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.1-6
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• 2021

In this paper, an efficient implementation of AES encryption algorithm is presented for CCTV image security using C# language. In this approach, an efficient S-Box is first designed for reducing the computation time which is required in each round process of AES algorithm, and then an CCTV image security system is implemented on the basis of this algorithm on a composite field GF(((22)2)2). In addition, the shared S-Box structure is designed for realizing the minimized memory space, which is used in each round transformation and key scheduling processes. Through performance evaluation, it was confirmed that the proposed method is more efficient than the existing method. The proposed CCTV system in C# language using Visual studio 2010.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.164-170
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• 2021

In VLSI design, partitioning is a task of clustering objects into groups so that a given objective circuit is optimized. It is used at the layout level to find strongly connected components that can be placed together in order to minimize the layout area and propagation delay. The most popular algorithms for partitioning include the Kernighan-Lin algorithm, Fiduccia-Mattheyses heuristic and simulated annealing. In this paper, we propose a adapted genetic algorithm searching solution space for the circuit partitioning problem, and then compare it with simulated annealing and genetic algorithm by analyzing the results of implementation. As a result, it was found that an adaptive genetic algorithm approaches the optimal solution more effectively than the simulated annealing and genetic algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.878-883
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• 2018

A jamming design scheme to disturb target position estimation of a bistatic multiple-input multiple-output(MIMO) radar system is presented. The proposed method exploits the received signals from distributed multiple electronic sensors and combines them to produce a jamming signal. The proposed algorithm can eliminate the target by transmitting the delayed sum or the weighted sum of the received senor signals. Simulation results confirm the performance of the proposed method.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.4
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• pp.41-49
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• 2020

The purpose of this study was to investigate the use of the Deep Neural Networks(DNN) model to classify user's emotions, in particular Electroencephalography(EEG) toward Virtual-Reality(VR) based 3D design alternatives. Four different types of VR Space were constructed to measure a user's emotion and EEG was measured for each stimulus. In addition to the quantitative evaluation based on EEG data, a questionnaire was conducted to qualitatively check whether there is a difference between VR stimuli. As a result, there is a significant difference between plan types according to the normalized ranking method. Therefore, the value of the subjective questionnaire was used as labeling data and collected EEG data was used for a feature value in the DNN model. Google TensorFlow was used to build and train the model. The accuracy of the developed model was 98.9%, which is higher than in previous studies. This indicates that there is a possibility of VR and Fast Fourier Transform(FFT) processing would affect the accuracy of the model, which means that it is possible to classify a user's emotions toward VR based 3D design alternatives by measuring the EEG with this model.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.404-404
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• 2023

최근 국지성 집중호우 등 기상이변의 영향으로 침수피해의 위험성은 점차 증가하는 추세이고, 도시화로 인한 불투수면적의 증가, 녹지공간의 감소, 도시의 난개발 등 물순환 체계의 왜곡에 따른 침수로 인한 피해가 다수 발생하고 있다. 침수 발생 시 막대한 인적 및 물적 피해가 발생할 수 있기에 재난초기에 재난관리자원의 신속한 확보와 동원은 피해확산 방지에 매우 중요하고, 자원의 부족이나 동원의 지연으로 초기 대응이 늦어질 경우 피해가 확대될 수 있기에 침수발생 특성에 따른 필요 자원의 비축 및 동원이 필요하다. 하지만, 재난관리자원은 종류가 다양하고 요구되는 비축량이 많기에 모든 재난관리자원을 보유하고, 활용하기에는 어려움이 따른다. 따라서 침수피해재난을 중심으로 최적 자원 비축을 통한 효율적인 재난관리자원 운영 및 관리체계의 마련이 필요하다. 본 연구에서는 과거 20년(2001년~2020년) 동안 발생한 침수피해 관련 재난(호우, 태풍, 풍랑)사례를 통해 재난발생 시 동원된 자원현황을 분석하였다. 재해연보, 관련 백서 및 보고서, 침수흔적도 등의 수집 및 분석을 통해 지자체 침수피해 현황을 분류하고, 침수재난과 관련된 자원의 비축 및 운용 사례 분석을 통해 장비 28종, 자재 6종을 확인하였다. 본 연구는 침수재난 발생 시 지자체별 침수피해 규모와 필요한 재난관리자원을 도출한 점에서 그 의미가 있으며, 향후 재난관리자원의 효율적인 비축 및 관리계획 수립에 기초자료로 활용할 수 있을 것으로 기대된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.2-5
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• 2021

With the recent development of the Internet of Things (IoT) technology, various terminals are being connected to the Internet. As a result, the amount of IoT data is also increasing, and an index key that can efficient analyze the large-scale IoT data is proposed. Existing index keys have only time and space information, so if data stored in index tables and instance tables were queried using repetition or join operation, IoT data was embedded in the index key of the proposal to create OLAP-based big tables to minimize the number of repetitions or join times.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.107-108
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• 2023

기업 및 공공기관의 클라우드 서비스 도입이 확산되면서 업무 시스템에 대한 보안 요구사항이 변화하고 있다. 기존에는 보호해야 할 정보자산이 물리적으로 외부와 분리된 내부 공간에 집중되었다면 클라우드 환경에서는 자산의 분포 범위가 넓어지면서 내부와 외부의 경계가 모호해진다. 따라서 경계 기반의 전통적인 보안 방식은 클라우드 기반 업무환경에 적합하지 않으며 정보 서비스를 이용하는 전 주기에서 암묵적인 신뢰를 배제하고 지속적으로 검증을 수행하는 제로 트러스트 기반의 업무 시스템 운영이 필요하다. 본 논문에서는 스토리지 클라우드 서비스인 아마존 웹 서비스 S3(Simple Storage Service)에 대하여 제로 트러스트 모델을 설계하고, 직접 서비스를 운영하며 제안된 제로 트러스트 모델의 안전성을 검증한다. 제로 트러스트 모델은 스토리지에 접근하는 사용자에 대한 인증 및 식별 기술, 스토리지 암호화 기술, 암호화 키 관리 기술을 활용하여 설계하였으며 제로 트러스트 기술 적용 시, 스토리지 보안성이 향상되는 것을 실제 서비스 운영을 통한 실험을 통해 확인하였다.

• Annual Conference of KIPS
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• 2008.11a
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• pp.1500-1503
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• 2008

H.264와 같은 고압축 비디오처리 기법의 등장으로 기존의 MPEG2와 같은 비디오 압축에서 H.264로의 비디오 트랜스코딩이 증가되고 있지만, 고압축 비디오 콘텐츠의 온라인과 오프라인에서 불법배포는 현재 문제가 되고 있다. 본 논문에서는 다이렉트쇼 환경 기반에서 고압축과 저작권 보호를 위한 비디오 트랜스 코딩과 워터마킹을 구현한다. 제안한 방법은 다이렉트쇼의 필터를 이용하여 MPG,WMV를 H.264로 비디오 트랜스코딩을 하고 이와 함께 비디오의 공간영역 특성을 이용하여 저작권 보호를 위한 강인한 워터마킹을 구현한다. 실험 결과 MPG,WMV를 H.264로 트랜스코딩에서 H.264의 QP(Quantization parameter)를 15로 하고 화면간 반복을 10프레임으로 하였을 경우 저작권 보호를 위하여 삽입된 워터마크는 평균 99% 검출됨을 확인하였고, 또한 트랜스코딩중 워터마크삽입에 따른 시간지연은 전체 트랜스코딩시간의 5.7%가 됨을 확인할 수 있었다. 제안한 방법은 저작권 삽입 기능가지는 트랜스코딩 소프트웨어를 필요로 하는 Digital TV방송, IPTV, DVD 사업에 사용 될 수 있을 것이다.

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.197-208
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• 2020

This study was carried out to analyze spatial and temporal incidence characteristics of scrub typhus and predict the future incidence of scrub typhus since the incidences of scrub typhus have been rapidly increased among vector-borne diseases. A maximum entropy (MaxEnt) ecological model was implemented to predict spatial distribution and incidence rate of scrub typhus using spatial data sets on environmental and social variables. Additionally, relationships between the incidence of scrub typhus and critical spatial data were analyzed. Elevation and temperature were analyzed as dominant spatial factors which influenced the growth environment of Leptotrombidium scutellare (L. scutellare) which is the primary vector of scrub typhus. A temporal number of diseases by scrub typhus was predicted by a deep neural network (DNN). The model considered the time-lagged effect of scrub typhus. The DNN-based prediction model showed that temperature, precipitation, and humidity in summer had significant influence factors on the activity of L. scutellare and the number of diseases at fall. Moreover, the DNN-based prediction model had superior performance compared to a conventional statistical prediction model. Finally, the spatial and temporal models were used under climate change scenario. The future characteristics of scrub typhus showed that the maximum incidence rate would increase by 8%, areas of the high potential of incidence rate would increase by 9%, and disease occurrence duration would expand by 2 months. The results would contribute to the disease management and prediction for the health of residents in terms of public health.