• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.291-307
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• 2021

There has been global efforts to prevent the further spread of the COVID-19 and get society back to normal. 'Contact tracing' is a crucial way to detect the infected person. However the contact tracing makes another concern about the privacy violation of the personal data of infected people, released by governments. Therefore Google and Apple are announcing a joint effort to enable the use of Bluetooth technology to help governments and health agencies reduce the spread of the virus, with user privacy and security central to the design. However, in order to provide the improved tracing application, it is necessary to identify potential security threats and investigate vulnerabilities for systematically. In this paper, we provide security analysis of Privacy-Preserving COVID-19 Contact Tracing App with STRIDE and LINDDUN threat models. Based on the analysis, we propose to adopt a verifiable computation scheme, Zero-knowledge Succinctness Non-interactive Arguments of Knowledges (zkSNARKs) and Public Key Infrastructure (PKI) to ensure both data integrity and privacy protection in a more practical way.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.194-196
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• 2003

적응광학은 넓은 의미로 실시간으로 빛을 제어하는 분야를 의미하며, 천문학 관련 분야에 제한하면 대기에 의해 왜곡된 빛의 파면을 실시간으로 보상시켜주는 기술을 의미한다. 적응광학은 대기과학, 광학분야, 광전자분야, 전기분야, 기계분야 등의 복합학문으로 1950년 Backcock에 의하여 제안된 후 1970～80년대 미소에 의해 고에너지레이저(HEL, High Enegry Laser)와 위성추적시스템의 구성요소로 개발되었다 1980년 일반에 공개되었다. (중략)

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.428-432
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• 2008

대수층의 저유량이 풍부한 강변여과수 개발 예정지역의 충적충(지표면하 25$\sim$35 m 구간)에서 수리전도도와 증분산지수의 규모종속효과를 규명하기 위해 양수시험과 수렴흐름 추적자시험이 수행되었다. 양수시험과 추적자시험의 규모는 2 m 와 5 m 이었으며 양수시험은 5개 공, 추적자시험은 3개 공을 이용하여 수행되었다. 양수시험은 일정한 양수율(2,500 m$^3$/day)로 수행되었으며, 양수 시작 후 경과시간에 따른 수위변화 자료를 AQTESOLV 3.5 프로그램에 입력하여 해석하였다. 시험대수층의 수리전도도는 양수정에서 1.745$\times$10$^{-3}$ m/sec, 양수정에서 이격거리가 2 m 구간에서는 2.161$\times$10$^{-3}$ m/sec와 2.270$\times$10$^{-3}$ m/sec 이었으며, 이격거리가 5 m 구간에서는 2.452$\times$10$^{-3}$ m/sec와 2.591$\times$10$^{-3}$ m/sec로 산정되었다. 그리고, 양수정에서 회복시험 시 Theis(Recovery) 방법에 의해 해석된 수리전도도는 1.603$\times$10$^{-3}$ m/sec이었다. 양수정에서 관측정의 이격거리(d)에 따른 수리전도도(K) 증가함수는 log K = 0.0693logd-2.071와 log K = 0.08171og d-2.655로 추정되었으며, 결정계수는 각각 0.965와 0.979로서 매우 높게 나타났다. 따라서 양수정에서의 이격거리가 멀수록 수리전도도가 증가하는 규모종속을 확인하였으며, 또한 시험대수층의 수리전도도가 방사상으로 유사하게 분포하고 있음을 알 수 있었다. 수렴흐름 추적자시험의 양수율은 2,500 m$^3$/day 이었으며, 2개의 주입정에 염소이온 5 kg을 순간 주입하였다. 염소이온의 농도이력곡선을 작성하여 초기도달시간과 최고농도의 차이를 분석하였으며, 누적질량회수곡선을 통해 양수 후 경과시간에 따른 염소이온의 질량회수율을 분석하였다. 그리고, 염소이온농도 대 누적질량회수율의 이력그래프를 작성하여 누적질량회수율에 따른 염소이온농도의 증가와 감소 변화를 분석하였다. 또한, 염소이온농도의 증가/감소 구간에 대한 선형회귀분석을 수행하여 농도 증가율과 감소율의 변화를 파악하였다. 양수정에서 관측된 경과시간별 염소이온농도 자료를 CATTI 코드의 "Converging Radial Flow With Instantaneous Injection" 해석법에 적용하여 종분산지수를 추정하였다. 양수정에서 이격거리가 2 m인 경우의 종분산지수는 0.4152 m, 이격거리가 5 m인 경우의 종분산지수는 3.2665 m 이었다. 따라서 양수정에서 이격거리가 멀수록 종분산지수가 증가하는 규모종속효과를 확인하였으며, 또한 이격거리에 대한 종분산지수의 비는 각각 0.21과 0.65 정도로서 증가하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.382-385
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• 2016

본 연구는 포털사이트의 효율적이고 경험 디자인(User Experience Design : UX 디자인)적 설계가 가능하도록 제작하기 위하여 와이어 프레임에 대한 사용자의 시각궤적과 주시빈도를 확인한다. 국내 주요 포털 사이트를 점유비율에 따라 세 가지를 제시하고 로고의 유무에 따른 와이어 프레임을 제작하여 각 사이트의 화면분할과 정보영역을 분석한다. 시선추적 장치를 통해 총 6가지 와이어 프레임의 시각궤적 및 주시빈도를 확인하여 시선이 머무는 히트맵을 제시한다. 이를 통해 웹사이트의 디자인 설계시 페이지나 화면에 보이는 요소들의 효율적 배치를 위한 주시영역을 살펴본다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.11
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• pp.945-954
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• 1990

In this paper, we presents a robust adaptive control system design method in the work coordinate of the robot arm for conveyor tracking. In the design, if the weighting function $L_K$ is smaller than the design parameter then the transient characteristics of system becomes stable, if $L_K$ is larger than then the system becomes unstable. Proposed design method presented here is based on model referenece adaptive control and Popov stability theorem. By the utiliza/tion of an auxilary input, it is improved the transent characteristics of the system in comparison with the conventional model reference adptive control, since the rate of V and V(t) is large. The usefulness of a proposed design method has been confirmed by computer simulations.

• The Journal of the Acoustical Society of Korea
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• v.20 no.4
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• pp.5-11
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• 2001

Acoustic characteristics of the wedge-shaped anechoic tiles, used as absorbing lining materials for an anechoic water tank, were investigated for different wedge-apex angles. The anechoic tile base has the dimensions of 400mm x 385mm x 15.5mm. In order to investigate anechoic effect, the wedge-apex angles 30° and 60° were selected by using a ray-tracing method. The reflection loss of the anechoic tiles with and without wedges were experimentally studied at normal incident sound waves in water. In this experiment, the reflection loss of wedge-shaped anechoic tiles with the optimum wedge-apex angle 30° is larger than one with the angle 60° and one without wedges. The experimental results show that the wedge-shaped anechoic tiles with the wedge-apex angle 30°, optimized by using ray-tracing method, turn out better absorbing lining materials of an anechoic water tank.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.253-257
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• 2006

The objectives of this paper are to estimate home range and core habitat area of wild bores in Jirisan National Park of Korea. A radio-telemetry study was carried out on 5 wild boar individuals (3 females and 2 males). Except one individual whose enough data could not be collected, the mean home range size of 4 individuals was $5.13km^2$ (95% kernel) and mean core habitat area was $1.18{\pm}0.31km^2$ (50% kernel). Home-range sizes of 2 females were $6.21km^2\;and\;5.45km^2$ each, and that of 2 males were $5.15km^2\;and\;3.72km^2$ each, which means home-ranges of female boars were larger than those of male boars in this research. This result is presumed to have been caused by the fact that the males were sub adult individuals weighing 40 kg and 19 kg when they were captured for this research.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.115-124
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• 2008

In vehicular networks, vehicles should be able to authenticate each other to securely communicate with network-based infrastructure, and their locations and identifiers should not be exposed from the communication messages. however, when an accident occurs, the investigating authorities have to trace down its origin. As vehicles communicate not only with RSUs(Road Side Units) but also with other vehicles, it is important to minimize the number of communication flows among the vehicles while the communication satisfies the several security properties such as anonymity, authenticity, and traceability. In our paper, when the mutual authentication protocol is working between vehicles and RSUs, the protocol offers the traceability with privacy protection using pseudonym and MAC (Message Authentication Code) chain. And also by using MAC-chain as one-time pseudonyms, our protocol does not need a separate way to manage pseudonyms.

• The KIPS Transactions:PartB
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• v.18B no.4
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• pp.201-212
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• 2011

In this paper, we suggest a system of detecting a vehicle with lane violation, which can detect the vehicle with lane violation, by using the feature point tracking. The whole algorism in the suggested system of detecting a vehicle with lane violation is composed of three stages such as feature extraction, register and tracking in feature for the tracking-targeted vehicle, and detecting a vehicle with lane violation. The feature is extracted from the morphological gradient image, which results in constructing robust detection system against shadows, weather conditions, head lights and illumination conditions without distinction day and night. The system shows excellent performance for the data captured at day time, night time, and rainy night time as much as 99.49% for positive recognition ratio and 0.51% for error ratio. Also the system is so fast as much as 91.34 frames per second in average that it may be possible for real-time processing.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.36-42
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• 2001

This paper propose new sound localization algorithm that detects the sound source bearing in a closed office environment using two microphone array. The proposed Subband CPSP (Cross Power Spectrum Phase) algorithm is a development of previously Down CPSP method using subband approach. It first split the received microphone signals into subbands and then calculates subband CPSP which result in possible source bearings. This type of algorithm, Subband CPSP, can provide more robust and reliable sound localization system because it limits the effects of environmental noise within each subband. To verify the performance of the proposed Subband CPSP algorithm, a real time simulation was conducted and it was compared with previous CPSP method. From the simulation results, the proposed Subband CPSP is superior to previous CPSP algorithm more than 5％ average accuracy for sound source detection.