• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.13-23
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• 2008

In coastal region, eutrophication, Do deficit and red tide are frequently occurred by influx of fresh water. When the fresh water containing pollutants is discharged into the sea, the surrounding water is contaminated by dispersion of freshwater flowing into coastal waters. The prediction and analysis about the dispersion process of the discharged fresh water should be conducted. A modeling system using GUI was developed to simulate hydrodynamic flow and fresh water dispersion in coastal waters and to analyze the results efficiently. The modeling module of the system includes a tide model using a finite element method and a fresh water dispersion model using a particle-tracking method. This system was applied to predict the tidal currents and fresh water dispersion in Mokpo coastal zone. To verify accuracy of the hydrodynamic model, the simulation results were compared with observed sea level and time variations of tidal currents showing a good agreement. The fresh water dispersion was verified with observed salinity distribution. The dispersion model also was verified with analytic solutions with advection-diffusion problems in 1-dimensional and 2-dimensional simple domain. The system is operated on GUI environment, to ease the model handling such as inputting data and displaying results. Therefore, anyone can use the system conveniently and observe easily and accurately the simulation results by using graphic functions included in the system. This system can be used widely to decrease the environmental disaster induced by inflow of fresh water into coastal waters.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.1 s.114
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• pp.21-36
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• 2006

This study was undertaken to analyze the effects of pavement thermal properties and water retention characteristics on the surface temperature of the gray permeable cement concrete pavement during the summer. Following is a summary of major results. 1) The hourly surface temperature of pavement could be well predicted with a heat transfer model program that incorporated the input data of major meteorological variables including solar radiation, atmospheric temperature, dew point, wind velocity, cloudiness and the evaporation rate of the pavements predicted by the time domain reflectometry (TDR) method. 2) When the albedo was changed to 0.5 from an arbitrary starting condition of 0.3, holding other variables constant, the peak surface temperature of the pavement dropped by 11.5%. When heat capacity was changed to $2.5\;kJm^{-3}K^{-1}\;from\;1.5\;kJm^{-3}K^{-1}$, surface temperature dropped by 8.0%. When daily evaporation was changed to 1 mm from 2 mm, temperature dropped by 5.7%. When heat conductivity was changed to $2.5\;Wm^{-1}K^{-1}\;from\;1.5\;Wm^{-1}K^{-1}$, the peak surface temperature of the pavement fell by 1.2%. The peak pavement surface temperature under the arbitrary basic condition was $24.46^{\circ}C$ (12 a.m.). 3) It accordingly became evident that the pavement surface temperature can be most effectively lowered by using materials with a high albedo, a high heat capacity or a high evaporation at the pavement surface. The glare situation, however, is intensified by raising of the albedo, moreover if reflected light is absorbed into surrounding physical masses, it is changed into heat. It accordingly became evident that raising the heat capacity and the evaporative capacity may be the moot acceptable measures to improve the thermal characteristics of the pavement. 4) The sensitivity of the surface temperature to major meteorological variables was as follows. When the daily average temperature changed to $0^{\circ}C\;from\;15^{\circ}C$, holding all other variables constant, the peak surface temperature of the pavement decreased by 56.1 %. When the global solar radiation changed to $200\;Wm^{-2}\;from\;600\;Wm^{-2}$, the temperature of the pavement decreased by 23.4%. When the wind velocity changed to $8\;ms^{-1}\;from\;4\;ms^{-1}$, the temperature decreased by 1.4%. When the cloudiness level changed to 1.0 from 0.5, the peak surface temperature decreased by 0.7%. The peak pavement surface temperature under the arbitrary basic conditions was $24.46^{\circ}C$ (12 a.m.)

• Economic and Environmental Geology
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• v.51 no.6
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• pp.589-593
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• 2018

Democratic Peoples' Republic of Korea (DPRK) conducted the $6^{th}$ underground nuclear test at the Punggye-ri underground nuclear test site on September 27, 2017 12 hours 30 minutes of Korean local time. Comprehensive Nuclear-Test Ban Treaty Organization (CTBTO) under U.N. announced the body wave magnitude of the event was mb 6.1 while U.S. Geological Survey (USGS)'s calculation was mb 6.3. In this study, the differences of the magnitude estimates were investigated and verified. For this purpose, a source scaling between the $5^{th}$ and $6^{th}$ event, which's epicenters are 200 meters apart, was performed using seismic data sets from 30 broadband stations. The relative amplitude variations of the $6^{th}$ event compared to the $5^{th}$ event in the frequency domain was analyzed through the scaling. The increased amount of the bodywave magnitude $m_b$ for the $6^{th}$ event was calculated at 1 Hz, which was compared to those from USGS and CTBTO's calculations.

• Smart Media Journal
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• v.9 no.4
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• pp.97-101
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• 2020

Using passive electric field sensor which operates in non-contact mode, we can measure the electric potential induced from the change of electric charges on a sensor caused by the movement of human body or hands. In this study, we propose a new method, which utilizes PLN induced to the sensor around the moving object, to detect one's hand movement and extract gesture frames from the detected signals. Signals from the EPS sensors include a large amount of power line noise usually existing in the places such as rooms or buildings. Using the fact that the PLN is shielded in part by human access to the sensor, signals caused by motion or hand movement are detected. PLN consists mainly of signals with frequency of 60 Hz and its harmonics. In our proposed method, signals only 120 Hz component in frequency domain are chosen selectively and exclusively utilized for detection of hand movement. We use FFT to measure a spectral-separated frequency signal. The signals obtained from sensors in this way are continued to be compared with the threshold preset in advance. Once motion signals are detected passing throng the threshold, we determine the motion frame based on period between the first threshold passing time and the last one. The motion detection rate of our proposed method was about 90% while the correct frame extraction rate was about 85%. The method like our method, which use PLN signal in order to extract useful data about motion movement from non-contact mode EPS sensors, has been rarely reported or published in recent. This research results can be expected to be useful especially in circumstance of having surrounding PLN.

• Journal of the Korean GEO-environmental Society
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• v.23 no.8
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• pp.29-36
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• 2022

The importance of subsurface information is becoming crucial in urban area due to increase of underground construction. The position of underground facilities should be identified precisely before excavation work. Geophyiscal exporation method such as ground penetration radar (GPR) can be useful to investigate the subsurface facilities. GPR transmits electromagnetic waves to the ground and analyzes the reflected signals to determine the location and depth of subsurface facilities. Unfortunately, the readability of GPR signal is not favorable. To overcome this deficiency and automate the GPR signal processing, deep learning technique has been introduced recently. The accuracy of deep learning model can be improved with abundant training data. The ground is inherently heteorogeneous and the spacially variable ground properties can affact on the GPR signal. However, the effect of ground heterogeneity on the GPR signal has yet to be fully investigated. In this study, ground heterogeneity is simulated based on the fractal theory and GPR simulation is carried out by using gprMax. It is found that as the fractal dimension increases exceed 2.0, the error of fitting parameter reduces significantly. And the range of water content should be less than 0.14 to secure the validity of analysis.

• Journal of Ginseng Research
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• v.46 no.5
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• pp.628-635
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• 2022

Background: Ulcerative colitis (UC) is the large intestine disease that results in chronic inflammation and ulcers in the colon. Rg3-enriched Korean Red Ginseng extract (Rg3-RGE) is known for its pharmacological activities. Persicaria tinctoria (PT) is also used in the treatment of various inflammatory diseases. The aim of this study is to investigate the attenuating effects of Rg3-RGE with PT on oxazolone (OXA)-induced UC in mice. Methods: A total of six groups of mice including control group, OXA (as model group, 1.5%) group, sulfasalazine (75 mg/kg) group, Rg3-RGE (20 mg/kg) group, PT (300 mg/kg) group, and Rg3-RGE (10 mg/kg) with PT (150 mg/kg) group. Data on the colon length, body weight, disease activity index (DAI), histological changes, nitric oxide (NO) assay, Real-time PCR of inflammatory factors, ELISA of inflammatory factors, Western blot, and flow cytometry analysis were obtained. Results: Overall, the combination treatment of Rg3-RGE and PT significantly improved the colon length and body weight and decreased the DAI in mice compared with the treatment with OXA. Additionally, the histological injury was also reduced by the combination treatment. Moreover, the NO production level and inflammatory mediators and cytokines were significantly downregulated in the Rg3-RGE with the PT group compared with the model group. Also, NLR family pyrin domain containing 3 (NLRP3) inflammasome and nuclear factor kappa B (NF-𝛋B) were suppressed in the combination treatment group compared with the OXA group. Furthermore, the number of immune cell subtypes of CD4⁺ T-helper cells, CD19⁺ B-cells, and CD4⁺ and CD25⁺ regulatory T-cells (Tregs) was improved in the Rg3-RGE with the PT group compared with the OXA group. Conclusion: Overall, the mixture of Rg3-RGE and PT is an effective therapeutic treatment for UC.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.991-998
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• 2022

The purpose of this study is to develop GPU (Graphics Processing Unit) acceleration technique for 2-dimensional model and to assess the effectiveness for high resolution flood simulation in wide area In this study, GPU acceleration technique was implemented in the G2D (Grid based 2-Dimensional land surface flood model) model, using implicit scheme and uniform square grid, by using CUDA. The technique was applied to flood simulation in Jinju-si. The spatial resolution of the simulation domain is 10 m × 10 m, and the number of cells to calculate is 5,090,611. Flood period by typhoon Mitag, December 2019, was simulated. Rainfall radar data was applied to source term and measured discharge of Namgang-Dam (Ilryu-moon) and measured stream flow of Jinju-si (Oksan-gyo) were applied to boundary conditions. From this study, 2-dimensional flood model could be implemented to reproduce the measured water level in Nam-gang (Riv.). The results of GPU acceleration technique showed more faster flood simulation than the serial and parallel simulation using CPU (Central Processing Unit). This study can contribute to the study of developing GPU acceleration technique for 2-dimensional flood model using implicit scheme and simulating land surface flood in wide area.

• The Journal of the Acoustical Society of Korea
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• v.42 no.4
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• pp.329-344
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• 2023

In this study, we comprehensively analyze the generalization performance of various deep learning-based active sonar target classifiers when applied to small and imbalanced active sonar datasets. To generate the active sonar datasets, we use data from two different oceanic experiments conducted at different times and ocean. Each sample in the active sonar datasets is a time-frequency domain image, which is extracted from audio signal of contact after the detection process. For the comprehensive analysis, we utilize 22 Convolutional Neural Networks (CNN) models. Two datasets are used as train/validation datasets and test datasets, alternatively. To calculate the variance in the output of the target classifiers, the train/validation/test datasets are repeated 10 times. Hyperparameters for training are optimized using Bayesian optimization. The results demonstrate that shallow CNN models show superior robustness and generalization performance compared to most of deep CNN models. The results from this paper can serve as a valuable reference for future research directions in deep learning-based active sonar target classification.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.67-67
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• 2022

국가 물관리 측면에서 증발산량과 토양수분량은 자연계 손실로서 국내 수자원 총량의 약43%(563억 m³/년)를 차지하며, 수자원의 계획과 개발, 물순환 과정 규명 및 다양한 수재해 분석 등을 위한 수문 요소이다. 정부는 2005년 「수문조사 선진화 5개년 계획」과 2008년 「제1차 수문조사기본계획(2010~2019년)」을 통해 2019년까지 증발산량과 토양수분량 관측소 확대(각각 25개 지점) 기반을 마련하였고 「수자원의 조사·계획 및 관리에 관한 법률」에 따라 매년 공인 수문 자료로 증발산량과 토양수분량을 측정하고 있다. 증발산량과 토양수분량은 댐 유역의 정밀한 물순환 해석에도 매우 중요한 정보로서 현재 K-water에서의 관측은 일부 시험유역(용담댐 유역)의 flux tower에 의한 에디공분산법(Eddy Covariance Method) 및 토양수분 센서(TDR, Time Domain Reflectometery)에 의한 지점 자료의 생산만 각각 이루어지고 있다. 본 연구에서는 K-water 댐 유역의 증발산량 및 토양수분량 관측 현황과 그간 관측된 자료의 특성을 각종 경향성 분석 등과 함께 소개하고자 한다, 증발산량의 경우는 2개소의 flux tower를운영(덕유산 지점 2011년 이후, 용담 지점 2017년 이후)하고 있으며, 토양수분량은 총 7개소(계북, 천천, 상전, 안천, 부귀, 주천 지점 2013년 이후, 장계 지점 2017년 이후)에 TDR센서를 설치, 계측 운영 중이다. 이렇게 관측된 자료는 매년 홍수통제소 주관 관련 전문가 공인심사를 통해 일자료 기준으로 한국수문조사연보에 수록되고 있으며, K-water에서도 연보를 통해 공개된 자료를 기준으로 공공데이터포털(data.go.kr) 등과 연계하여 온라인 자료 서비스 중이다. 한편, 최근 2020년 「제2차 수문조사 기본계획(2020~2029년)」에서는 수자원 위성 개발연구와 연계하여 위성을 활용한 증발산량과 토양수분량 산정 연구의 필요성이 강조되고 있다. 하지만 본 연구에서 살펴본 지점 자료만으로는 댐 유역을 포함한 광역단위의 시계열 공간정보를 생산하기 한계가 있으며, 댐 유역과 국내 전 지역의 공간 시계열 증발산량 및 토양수분량 자료 산정과 활용 방안에 대해 정립하고, 나아가 위성영상을 활용한 댐 유역 증발산량·토양수분량 관측 가이드라인 마련 등을 위해서는 국가적으로 많은 재원의 투입과 노력이 필요한 상황이다.

• Korean Journal of Social Welfare Studies
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• v.41 no.2
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• pp.247-278
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• 2010

There are three main purposes of this study: (a) to investigate the developmental trajectories of psychological resilience, social resilience, and school resilience of adolescents in poverty, (b) to identify the longitudinal relationship of three resiliences and (c) to examine the protective factors that help adolescents to develop successfully in the face of poverty. Data were drawn from Korea Youth Panel Survey(KYPS), a longitudinal panel study on Middle school students in the second grade. Sample consists of 648 adolescents in poverty who particiipated in the KYPS. Latent Growth Curve Model(LGM) was used to analyze intraindividual changes in resiliences and interindividual differences in these changes. And AMOS 7.0 and SPSS 15.0 were used. In this study, it is concluded that the resilience of adolescents in poverty is the construct that has uni-dimensionality and multi-dimensionality at the same time. Therefore, in order to improve resilience of adolescents in poverty, protective factors associated with each resilience have to be increased. Those findings have provided various theoretical and practical implications for social workers and professionals helping adolescents in poverty.