• Proceedings of the Korea Water Resources Association Conference
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• 2002.02a
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• pp.309-324
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• 2002

국내의 경우 관개용수의 대부분은 벼생육을 위한 논의 관개응수로 사용되고있다. 농업용수 이용은 약 150억㎥/year, 이는 하천유지수량을 제외한 전체 물이용량 237억㎥/year의 약 63%에 해당한다. 최근 물절약은 가장 중요한 사회, 경제적인 이슈 중의 하나로 인식되고 있다. 그러나, 국내의 경우 관개효율은 여전히 낮아 약 35%의 관개용수가 손실되는 것으로 추정되고있다. 비록 관개에서의 물절약이 시급한 문제이기는 하지만 용수손실 원인에 따른 손실량에 대한 정량적인 연구가 행해지지 않았었다. 손실 원인에 따른 손실량을 계측하기 위한 시험지구로 경기 평택의 이동지구를 선정하였다. 시험지구의 주수원공으로는 유역면적 9,440ha, 관개면적 2,027ha인 이동저수지이며 상류유역에 미산 및 용덕저수지가 위치하고 관개지구내에 원암 및 은산양수장이 있다. 시험지구의 계측시설은 강우량 계측을 위하여 자기강우계를 설치하였고 저수위, 하천수위 및 응배수로의 수위 측정을 위하여 수위계를 설치하였다. 강우계는 4개소에 설치되었으며 수위계는 26개소에 설치되었다 강우계는 지구내의 저수지 및 양수장 관리사 부근 4개소에 전도형 자기우량계를 설치하였다. 수위계 26개소 중에서 저수지의 저수위 계측지점이 3개소이며 하천수위 계측지점이 2개소 그리고 용배수로의 간선수로 시점부와 간지선 분기점 등의 주요지점에 21개소의 계측지점이 있다. 모든 계측지점의 계측기에는 자체 혹은 별도의 자료저장용 데이터로거가 부착되어 현장 계측자료를 저장하도록 설치 되어있다. 강우계는 전도형강우계(tipping bucket type)이며 수위계는 계측지점의 특징에 따라 여러종류의 수위계측기가 설치되었다 예를들어 초음파수위계(ultrasonic-wave type), 부표식수위계(float type) 그리고 압력식수위계(Pressure type)가 설치되어 있다. 현장 계측기의 전원은 한국전력 전원 혹은 태양전지 및 축전지를 사용하였다. 수위계측지점의 유량을 환산하기 위하여 계측지점의 단면조사와 유속측정을 통해서 수위-유량관계(rating curve)를 규명하였다. 시험지구의 관개효율 및 용수손실 규명 등에 관한 기본자료를 수집하기 위해서는 계측시스템의 운영은 장기간으로 지속 되어야 한다

• The KIPS Transactions:PartB
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• v.12B no.2 s.98
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• pp.157-166
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• 2005

In 3D virtual environment the description of character' s movement that has utilized the conventional key-frame technique is gradually being developed toward the application of motion control method to generate more realistic and natural motion. Even the motion control method, however, has the limitation for expression of character's motion adapted to the ground properties of virtual world. That is, the walking motions of character are not only, for the most part, so uniform simple and repeated often as to feel to be tedious, but also the unnatural motion in which the tips of the toes soak through a plane or float in the air discording with the conditions of terrain lowers the semblance of reality. This paper proposes an adaptive motion control method for human figure locomotion in virtual environments or games, in which the walking motion is dynamiccally adapted to the ground's sliding properties. We compute an optimal parameters for one cycle of walking motion adapted to the ground properties by combining the coefficient of friction and centripetal force, and therefrom we induce a set of nonskid speed corresponding to various sliding properties of the ground.

• Resources Recycling
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• v.14 no.2
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• pp.3-9
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• 2005

A study on the air and gravity separation has been performed for the removal of chlorine containing materials from ASR of end-of-life vehicles. The gravity separation was also conducted on waste plastics collected from ASR. In this work, ASR were previously shredded to pass through 8 mm sieve prior to separation tests and the gravity separation of waste plastics was conducted for three different particle sizes. The two-stage air classification was conducted with the range of air flow rate of 9~20 M$^3$/hr at first stage and 25~34 M$^3$/hr at second stage, respectively. The fraction of overflow product was remarkably increased in the 2nd stage air classification because of high air flow rate while that of underflow product obtained from 1st stage air classification was found to be 62~66%. From the results of gravity separation on waste plastics, it was also found that the amount of the float product was much greater than sink product. It is believed that the gravity separation may be used very efficiently for the removal of calorine bearing materials from waste plastics.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.105-105
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• 2016

최근 기후변화 위기에 따른 대책으로 하천 유량 모니터링이 제시될 정도로 유량자료의 중요성이 확대되고 있다. 하천의 유량자료는 수자원개발 및 하천 방재의 중요한 기초자료로 이용되기 때문에 유량 산정 결과에 대한 신뢰도 즉, 측정 불확도를 정량적으로 제시하기 위한 연구는 오래 전부터 많은 연구자들에 의해 수행되었다. 1963 ~ 1970년에 영국 및 미국의 다수 하천의 유량 측정자료를 활용하여 국제표준화기구(ISO)에서 제시한 ISO 748이 대표적인 지침서이다. 현재 국내 유량조사 업무에서도 ISO 748의 측정 불확도 평가 방식을 이용하여 유량 측정 결과의 신뢰도를 제시하고 있다. 하지만 하천 유량조사는 현장 상황과 측정 인력의 경험 등에 따라 차이가 크게 발생할 수 있으며, 최근 첨단 센서를 활용한 유량 측정 기법들이 다수 개발되어 사용 중일 뿐만 아니라 측정 불확도 평가 체계를 GUM(Guide to the Expression of Uncertainty in Measurement)으로 변화해가고 있는 추세 등을 고려하였을 때 기존의 ISO 748에서 제시한 유량 측정 불확도 평가 방법에 대한 재검토에 대한 요구가 증대되고 있다. 특히 국내에서 홍수 시 유량 조사 방법으로 가장 많이 사용하고 있는 부자법의 경우 ISO 748에서 제안한 방법으로 측정 불확도를 제시하고 있지만 실제적으로 현장 상황을 고려하지 못하고 있는 것이 사실이다. 예를 들어 육안으로 관측하기 어려워 부자의 유하거리를 직선으로 가정함에 따른 불확도를 포함하지 못하고 있고, 부자가 유하하는 동안 부자의 흘수가 일정하지 않음에 따른 불확도를 포함하지 못하고 있다. 특히 부자 투하 측선과 유량 측정 단면을 부자가 지나가는 측선이 다름에 따른 불확도는 반드시 포함되어야 하지만 고려할 방법이 없어 아직까지 반영되지 못하고 있는 실정이다. 이에 본 연구에서는 부자를 이용한 유속 측정 불확도 산정에 있어서 그동안 ISO 748에서 정량적으로 고려하지 못한 불확도 인자들에 대하여 영상기법을 활용한 실험적 검토를 통해 정량적인 평가 기준을 제시하고자 한다. 이를 위해 실제 하천 규모의 흐름을 재현할 수 있는 안동하천실험센터의 직선수로에서 다양한 수리조건에 대한 부자를 이용한 유속 측정을 실시하여 측정 불확도를 산정하고자 한다. 본 연구 결과는 향후 부자를 이용한 유량 측정 불확도 평가 방법을 개선할 수 있고, 더 나아가 부자를 이용한 유량 측정 방법의 문제점을 개선할 수 있기 때문에 정확도를 향상에 크게 기여할 수 있을 것으로 기대한다.

• Convergence Security Journal
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• v.18 no.1
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• pp.85-91
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• 2018

In this study, we design a marine environmental information service system with satellite images based on satellite images to reduce the damage caused by changes in the marine environment. The system provides satellite oceanographic information such as water temperature, chlorophyll, float, etc. as hierarchical texts, which is implemented as a unit module Web service so that it can be expanded in OpenAPI environment. And stability of system plug-in portability, service hours, data extraction precision and speed are used as a basis for diagnosing service stability. By securing the function and performance of the service system implemented in this study, it can be expanded to a complex technology that can customize the users by group by adding not only general services of existing systems operated by location but also information about a specific interested areas. Especially, various other items of interest including marine environment information are developed in modules, so we expect to be able to expand and service the system by plugging into the system and to spread it in technical linkage with the related institution information system.

• Journal of Korean Society on Water Environment
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• v.35 no.2
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• pp.99-104
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• 2019

The objective of this study was to investigate the relationship between the biomass of cyanobacteria and the concentration of 2-methylisoborneol (2-MIB) in the lower Gongji stream. The investigation was done using a field study that was conducted from 2015 to 2017. The 2-MIB concentration in the lower Gongji stream ranged from 0 to 153 ng/L, while the upper stream had 0 2-MIB concentration. 3 genera (Oscillatoria, Phormidium, Pseudanabaena) of cyanobacteria were detected in the lower Gongji stream with 2-MIB concentration. Among these 3 genera, an increase in Phormidium, Pseudanabaena biomass was associated with an increase in 2-MIB concentration. Accordingly, Phormidium, Pseudanabaena were regarded as the biological source of 2-MIB in that area. In October 2017, although planktonic cyanobacteria occurred less frequently, many benthic cyanobacteria mats were observed on the surface of the water body. Therefore, the high 2-MIB concentration, which exceeded 110 ng/L, can likely be attributed to the benthic cyanobacteria. In a laboratory experiment, individual Oscillatoria filaments were aggregated to form a colony with a higher density. This colony tended to float on the water surface. Cyanobacteria mats after floating aggregated mats were distributed in a net shape on the bottom.

• Particle and aerosol research
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• v.16 no.4
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• pp.73-94
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• 2020

Particulate infectious sources, including infectious viruses, can float in the air, causing airborne infections. To prevent indoor airborne infection, dilution control by ventilation and indoor air cleaners are frequently used. In this study, the risk of airborne infection by the operation of these two techniques was evaluated. In case of dilution control by ventilation, a high efficiency air filter was embedded at the inlet of supply air. In this study, infectious source reduction devices such as indoor air cleaner include all kinds of mechanical-filters, UV-photo catalysts and air ionizers through which air flow is forced by fans. Two mathematical models for influenza virus were applied in an infant care room where infants and young children are active, and the risk reduction efficiency was compared. As a result, in the case of individually operating the ventilator or the infectious source reduction device, the airborne infection risk reduction efficiencies were 55.2~61.2% and 53.8~59.9%, respectively. When both facilities were operated, it was found that the risk of airborne infection was reduced about 72.2~76.8%. Therefore, simultaneous operation of ventilation equipment and infectious source reduction device is the most effective method for safe environment that minimizes the risk of airborne infection of respiratory infectious diseases. In the case of a space where sufficient ventilation operation is difficult, it was found that the operation of an infectious source reduction device is important to prevent the spread of infectious diseases. This study is meaningful in that it provides an academic basis for strategies for preventing airborne infection of respiratory infectious diseases.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1477-1482
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• 2022

Haze is a local weather phenomenon in which very small droplets float in the atmosphere, and the amount and characteristics of haze may vary depending on the region. In particular, these haze reduce visibility, which can cause air traffic interference and vehicle traffic accidents, and degrade the quality of security CCTVs and so on. Therefore, in the past 10 years, research on haze removal has been actively conducted to reduce damage caused by haze. In this study, local haze removal is performed by weight generation using a haziness degree evaluator to adaptively respond to haze-free, homogeneous haze, and non-homogeneous haze cases. And the proposed method improves the limitations of the existing static haze removal method, which assumes that there is haze in the input image and removes the haze. We also demonstrate the superiority of the proposed method through quantitative and qualitative performance evaluations with benchmark algorithms.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.175-182
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• 2022

In our daily life, we come across different types of information, for example in the format of multimedia and text. We all need different types of information for our common routines as watching/reading the news, listening to the radio, and watching different types of videos. However, sometimes we could run into problems when a certain type of information is required. For example, someone is listening to the radio and wants to listen to jazz, and unfortunately, all the radio channels play pop music mixed with advertisements. The listener gets stuck with pop music and gives up searching for jazz. So, the above example can be solved with an automatic audio classification system. Deep Learning (DL) models could make human life easy by using audio classifications, but it is expensive and difficult to deploy such models at edge devices like nano BLE sense raspberry pi, because these models require huge computational power like graphics processing unit (G.P.U), to solve the problem, we proposed DL model. In our proposed work, we had gone for a low complexity model for Audio Event Detection (AED), we extracted Mel-spectrograms of dimension 128×431×1 from audio signals and applied normalization. A total of 3 data augmentation methods were applied as follows: frequency masking, time masking, and mixup. In addition, we designed Convolutional Neural Network (CNN) with spatial dropout, batch normalization, and separable 2D inspired by VGGnet [1]. In addition, we reduced the model size by using model quantization of float16 to the trained model. Experiments were conducted on the updated dataset provided by the Detection and Classification of Acoustic Events and Scenes (DCASE) 2020 challenge. We confirm that our model achieved a val_loss of 0.33 and an accuracy of 90.34% within the 132.50KB model size.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.233-240
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• 2023

p-type Tunnel Oxide Passivating Contacts (TOPCon) solar cell is fabricated with a poly-Si/SiO_x structure. It simultaneously achieves surface passivation and enhances the carriers' selective collection, which is a promising technology for conventional solar cells. The quality of passivation is depended on the quality of the tunnel oxide layer at the interface with the c-Si wafer, which is affected by the bond of SiO formed during the subsequent annealing process. The highest cell efficiency reported to date for the laboratory scale has increased to 26.1%, fabricated by the Institute for Solar Energy Research. The cells used a p-type float zone silicon with an interdigitated back contact (IBC) structure that fabricates poly-Si and SiO_x layer achieves the highest implied open-circuit voltage (iV_oc) is 750 mV, and the highest level of edge passivation is 40%. This review presents an overview of p-type TOPCon technologies, including the ultra-thin silicon oxide layer (SiO_x) and poly-silicon layer (poly-Si), as well as the advancement of the SiO_x and poly-Si layers. Subsequently, the limitations of improving efficiency are discussed in detail. Consequently, it is expected to provide a basis for the simplification of industrial mass production.