• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.421-428
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• 2017

The spatial distribution and abundance of fish species was estimate near Dok-do, East Sea of Korea by conducting midwater trawl survey with hydroacoustic method. Acoustic and midwater trawl data were collected onboard the R/V Tamgu 21 during 7-8 March 2016. Acoustic data were collected at the frequencies of 38 and 120 kHz and converted to nautical area scattering strength ($m^2/nmile^2$). Species are distributed mainly over an extent of 30-55 m, generally around southwest of Dok-do; the squid Watasenia scintillans was the dominant species found. The length-weight function and target strength of squid and other fishes were used to estimate the W. scintillans stock at 2499.1 tons and other fish at 43.8 tons during the winter season. The hydroacoustic method offers an approach for the determination of the biomass and vertical and spatial distributions of species aggregating near Dok-do, East Sea of Korea.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.283-290
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• 2011

A Raman LIDAR system has been designed and constructed for quantitative measurement of water vapor mixing ratio. The comparison with commercial microwave radiometer and global navigation satellite system(GNSS) was performed for the precipitable water vapor(PWV) profile and total PWV. The result shows that the total GNSS-PWV and LIDAR-PWV have good correlation with each other. But, there is small difference between the two methods because of maximum measurement height in LIDAR and the GNSS method. There are some significant differences between Raman and MWR when the water vapor concentration changes quickly near the boundary layer or at the edge of a cloud. Finally we have decided that MWR cannot detect spatial changes but LIDAR can measure spatial changes.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.75-83
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• 2022

Korea, which has the highest pedestrian fatality rate among OECD countries, is making efforts to improve the safe walking environment by enacting laws focusing on pedestrian. Spatial clustering was conducted with scan statistics after examining the social network data related to traffic accidents for children and seniors. The word cloud was used to examine people's recognition Campaigns for children and literature survey for seniors were in main concern. Naedang and Yongsan are the regions with the highest relative risk of weak pedestrian for children and seniors. On the contrary, Bongmu and Beomeo are the lowest relative risk region. Naedang-dong and Yongsan-dong of Daegu Metropolitan City were identified as vulnerable areas for pedestrian safety due to the high risk of pedestrian accidents for children and the elderly. This means that the scan statistics are effective in searching for traffic accident risk areas.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.8
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• pp.683-688
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• 2014

This paper presents a high-performance flexible tactile sensor based on inorganic silicon flexible electronics. We created 100 nm-thick semiconducting silicon ribbons equally distributed with 1 mm spacing and $8{\times}8$ arrays to sense the pressure distribution with high-sensitivity and repeatability. The organic silicon rubber substrate was used as a spring material to achieve both of mechanical flexibility and robustness. A thin copper layer was deposited and patterned on top of the pressure sensing layer to create a flexible temperature sensing layer. The fabricated tactile sensor was tested through a series of experiments. The results showed that the tactile sensor is capable of measuring pressure and temperature simultaneously and independently with high precision.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.640-644
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• 2009

현재 태양광 산업에서는 고정식 태양광 발전장치보다 발전 효율이 우수한 추적식 태양광 발전장치를 개발하는 연구가 활발하게 진행되고 있다. 추적식 태양광 발전장치는 고정식에 대비하여 단위면적당 일사량을 최대로 유지할 수 있을 뿐만 아니라, 일조시간을 최대로 하여 태양전지의 발전효율을 극대화할 수 있다. 따라서 정밀하면서도 저렴한 태양위치 추적장치는 태양광 발전사업의 경제성을 높이고, 성능 대비 투자비용을 낮춰 태양광 발전설비의 보급을 촉진시켜줄 수 있는 중요한 기술이다. 본 연구는 태양위치를 감지하는데 센서를 사용하지 않고 천문학과 수학을 이용하여 정밀도 1분($0.016^{\circ}$)이내의 태양위치를 계산하는 알고리즘에 관한 것이다. 본 연구에서 제안하는 알고리즘은 장치의 제작비용을 낮추어 줄 뿐 아니라, 발전효율도 높여준다. 구현된 알고리즘을 적용시킨 추적식 태양광 발전장치를 운용 실측한 결과, 최대 30초($0.0038^{\circ}$)의 오차를 보여 추적식 발전장치의 경제성을 높일 수 있고, 시간복잡도(Time Complexity)와 공간복잡도(Spatial Complexity)가 낮아 실시간 태양 추적장치에 최적임을 확인하였다.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.245-252
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• 2013

Leaf area index (LAI) is important in explaining the ability of crops to intercept solar energy for biomass production, amount of plant transpiration, and in understanding the impact of crop management practices on crop growth. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal series of RapidEye imagery obtained from 2010 to 2012 using empirical models in a rice plain in Seosan, Chungcheongnam-do. Rice plants were sampled every two weeks to investigate LAI, fresh and dry biomass from late May to early October. RapidEye images were taken from June to September every year and corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). Linear, exponential, and expolinear models were developed to relate temporal satellite NDVIs to measured LAI. The expolinear model provided more accurate results to predict LAI than linear or exponential models based on root mean square error. The LAI distribution was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when RapidEye imagery was applied to expolinear model. The spatial trend of LAI corresponded with the variation in the vegetation growth condition.

• ETRI Journal
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• v.26 no.6
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• pp.565-574
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• 2004

Differential unitary space-time modulation (DUSTM) has emerged as a promising technique to obtain spatial diversity without intractable channel estimation. This paper presents a study of the application of DUSTM on multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems with frequency-selective fading channels. From the view of a correlation analysis between subcarriers of OFDM, we obtain the maximum achievable diversity of DUSTM on MIMO-OFDM systems. Moreover, an efficient implementation strategy based on subcarrier reconstruction is proposed, which transmits all the signals of one signal matrix in one OFDM transmission and performs differential processing between two adjacent OFDM blocks. The proposed method is capable of obtaining both spatial and multipath diversity while reducing the effect of time variation of channels to a minimum. The performance improvement is confirmed by simulation results.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.11a
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• pp.81-86
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• 2005

이 논문에서는 산불 발생의 패턴을 예측하기 위해 데이터 마이닝의 클러스터링 기법을 이용하여 산불 데이터를 그룹화하고 그 결과를 이용하여 산불 데이터의 상관관계를 분석하는 방법을 제안하였다. 즉, 클러스터링 기법을 이용하여 산불 데이터를 사용자가 원하는 수의 그룹으로 분류하고, 생성된 산불 데이터 클러스터 모델을 이용하여 새로운 유형의 산불패턴을 예측 할 수 있도록 하였다. 또한 결과 클러스터의 생성을 위해 이전의 산불 분포 데이터를 저장 관리하여 클러스터 간의 상관관계 분석을 통해 시퀀스를 생성하였고, 생성된 각각의 클러스터 시퀀스를 통합하여 클러스터들의 시퀀스를 추출하여 산불이 발생한 이후의 향후 발생 가능한 산불 유형을 예측하기 위한 방법을 제공하였다. 이는 과거에 발생된 산불의 유형뿐만 아니라 새로운 형태의 산불 유형 분류나 분석에 이용 가능하다.

• Journal of applied mathematics & informatics
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• v.32 no.5_6
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• pp.585-598
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• 2014

In this paper we consider the nonlinear parabolic problems with mixed boundary condition. Under comparatively mild conditions of the coefficients related to the problem, we construct the discontinuous Galerkin approximation of the solution to the nonlinear parabolic problem. We discretize spatial variables and construct the finite element spaces consisting of discontinuous piecewise polynomials of which the semidiscrete approximations are composed. We present the proof of the convergence of the semidiscrete approximations in $L^{\infty}(H^1)$ and $L^{\infty}(L^2)$ normed spaces.

• Korean Institute of Interior Design Journal
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• no.3
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• pp.38-45
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• 1994

The purpose of the present study is to suggest some directions intehdesign fo the hotel's lobby-lounge for public functions. In this study, some theoretical backgrounds reviewed from some literature were applied, and some results of the analysis of spatial features and utilized forms of public function for each sector respectively. with a review of some case studies were applied to this study as well, and thereby based on such application, it was attempted to experimentarily design the hotel's most desirable lobby-lounge for public functions. Specially in such design, expansion of the scale of the hotel's lobby-lounge, division of the line of a flow , the open front, approachability to the front desk, graudal arrangement of seats , formation of a walkway, and were service facilities were considered. In conclusion , since the hotel's lobby-lunge for public functions is a space which can accomodate various functions different from any other public space, thereby having a unique spatial system, it should be designed in consideration of the characteristics of function for each sector respectively.