• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.470-470
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• 2023

하천 및 저수지의 수량자료 수집을 위해 부자식 또는 레이더식 수위계 등의 계측기를 이용하여 수위의 변화를 측정한다. 그러나, 수량 모니터링을 위해 설치되는 계측기와 유지관리를 위한 인력소모 비용의 이유로 일부 지역에서만 제한적으로 수행되고 있어 정확한 수문 해석에 한계가 있다. 이에 본 연구에서는 저가의 센싱장비와 라즈베리파이를 활용한 ICT 기술을 수량 모니터링분야에 적용하여 수위 모니터링 기술을 개발하고자 한다. 라즈베리파이(Raspberry Pi 3 B Model)는 오픈소스 기반의 초소형 컴퓨터로 여러 센서를 연결하여 다양한 수문 인자(토양수분, 온도, 수위 등)들을 측정할 수 있으며, 통신 모듈이 기본 내장되어 있어 통신망 구축을 통해 측정데이터를 데이터베이스에 저장할 수 있다. 수위센서(eTape)와 초음파센서를 연결하여 실제 하천 유량 모니터링에 활용되고 있는 부자식 수위계 장비와 비교 분석을 통해 활용 가능성을 검증하고자 하였다. 검증방법은 인공강우실험을 위해 설치된 플륨관에 수위센서(eTape)와 초음파센서를 부착하여 기존 운영중인 부자식 수위계와 비교하였다. 부자식 수위계의 측정결과와 두 센서의 상관관계를 분석한 결과 결정계수(R²)가 0.94 이상으로 나타났다. 분석결과와 같이 기존 고가의 수위 관측장비들을 대체하여 저가의 센서 기반 모니터링 장비들의 실용화가 가능할 것이라 판단된다. 향후 연구에서는 다양한 센서(수위, 초음파, 카메라 등)를 이용하여 농업용수 물수지 분석에 활용할 계획이다. 농업용수는 수자원 총량 중 차지하는 비율이 높음에도 불구하고 정량적 데이터가 부족한 실정이며, 지역별 공급 특성이 다양하여 이를 계량화하기 위해서는 다수의 계측기가 필요하다. 따라서, 본 연구에서 개발중인 센서를 활용하여 물순환 과정의 정량적인 계측을 통해 농업용수의 효율적인 관리 및 농업용수의 하천기여도 평가 자료로 활용될 수 있을 것으로 판단된다.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.77-90
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• 2009

In this study, experimental analysis was performed about lateral load capacity and behavior of laterally loaded-bored rigid piles in muti-layered soil conditions. Lateral pile load tests were performed for muti-layerd soils consisting of different relative density. Ultimated lateral load capacities were measured from lateral load-displacement curves and compared with estimated values using theoretical methods. Bending moments and unit lateral capacity distribution of surrounding piles were measured from attached strain gauges and earth pressure sensors on the pile. It was found that ultimated lateral load capacities were different from the muti-layered soil conditions, and measured values were lower than estimated values. The bending moment distributions of the pile were similar all the time. Unit lateral capacity distributions were a little different from muti-layered soil conditions, but basically similar to the distribution proposed by Prasad and Chari (1999).

• Journal of the Korean Geotechnical Society
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• v.24 no.3
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• pp.53-63
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• 2008

The aim of this study was to validate the suitability of an digital image analysis (DIA) method to measure the degree of saturation in the unsaturated conditions. This study was carried out on the Joo-Mun-Jin standard sand. A one-dimensional sand column test was used in the constant water level condition to get the correlation equation between the color number ($C_n$) and the measured degree of saturation (5). In addition, the hanging wale. column technique to determine the soil-water charactenstic curve (SWCC) was performed in a Buchner funnel. The average degree of saturation ($S_{ave}$) in the SWCC could be obtained by substituting average color number at each suction head value with the $C_n\;-\;S$ correlation equation. Comparisons were made between the measured results by the hanging water column test and those obtained from DIA method. Results showed that the DIA method tested here provided fairly good saturation distribution values in the drying and wetting processes.

• Journal of the Korean Applied Science and Technology
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• v.40 no.2
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• pp.342-347
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• 2023

The purpose of this study was to determine the comparison of upper arm, trunk and core muscle activities according to different performance in high Plank exercise using weightless exercise equipment. Six males(age, 23.00±0.73 years; height, 172.95±2.05 cm; body mass, 66.83±2.75 kg; and BMI, 22.33±0.72 kg/m²) completed this study as the subjects. Four type's high Plank exercises using weightless exercise equipment were performed(high plank, HP; high plank with air walker, HPAW; high plank with surf board, HPSB; high plank with waist trainer, HPWT). For the EMG analysis, we measured the body muscle activities of right side on the deltoid(DT), triceps brachii(TB), latissimus dorsi(LD), and external oblique(EO). This research's results were as follows. DT, TB, LD, & EO muscle activities were greatest during HPSB(p=.000). Therefore, these results are expected to serve as basic data for high Plank exercise using weightless exercise equipment performance applications in effective exercise programs.

• Composites Research
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• v.22 no.4
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• pp.33-40
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• 2009

Fiber orientation effects on the impact surface fracture of the glass plates coated with the glass fiber/epoxy lamina layer were investigated using a small-diameter steel-ball impact experiment. Four kinds of materials were used: soda-lime glass plates, unidirectional glass fiber/epoxy layer(one ply, two plies)-coated, crossed glass tiber/epoxy layer (two plies)-coated glass plates. The maximum stress and absorbed fracture energy were measured on the back surface of glass plates during the impact. With increasing impact velocity, various surface cracks such as ring, cone, radial and lateral cracks appeared near the impacted site of glass plates. Cracks in the plate drastically diminished by glass fiber coating. The tiber orientation guided the directions of delamination and plastic deformation zones between the tiber layer and the glass plate. Impact surface-fracture indices expressed in terms of the maximum stress and absorbed energy could be used as an effective evaluation parameter of the surface resistance.

• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.49-56
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• 2009

In this paper, we present a daily activity monitoring system by using a wireless sensor network. The proposed system is installed in glove for activity monitoring. The RFID reader, to send data by using sensor network platform and RFID tag are small size, the shape of quadrangle, and operate in the frequency of 13.56 MHz. The sensor node can read RFID tags on the various objects used in daily living such as furniture, medicines, and kitchenwares. The sensor node reads the data of RFID tags, it transmits wireless packets to the sink node. The sink node sends the received packet immediately to a server system. The data from each RFID system is collected into a database, and then the data are processed to visualize the measurement of daily living activities of users. We provide a web-based monitoring system, and can see the number of RFID tag readings per day as bar charts. The result of experiments demonstrates that the way we propose can help to check the situation of life for people who live alone.

• Journal of the Korean Applied Science and Technology
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• v.39 no.2
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• pp.335-339
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• 2022

The purpose of this research was to investigate the comparison of core muscle activities according to different performance in static Plank exercise. Ten "J" University's males(age, 23.20±0.65 years; height, 174.54±1.51 cm; body mass, 70.00±2.24 kg; and BMI, 22.94±0.51 kg/m²) completed this study as the subjects. Four type's static Plank motions were performed(full Plank, FP; elbow Plank, EP; side Plank, SP; reverse Plank, RP). For the EMG analysis, we measured the core muscle activities of right side on the rectus abdominis(RA), external oblique(EO), latissimus dorsi(LD), and erector spinae(ES). This research's results were as follows. LD and ES muscle activities were greatest during RP(p<.001). RA and EO muscle activities were greatest during EP(p<.001). Therefore, this results are anticipated to serve as basic data for static Plank performance applications in effective exercise programs.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.839-849
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• 2017

Recently, the role of the kitchen has evolved from the space for previous survival to the space that shows the present life and culture. Along with these changes, the use of IoT technology is spreading. As a result, the development and diffusion of new smart devices in the kitchen is being achieved. The user experience for using these smart devices is also becoming important. For a natural interaction between a user and a computer, better interactions can be expected based on context awareness. This paper examines the Natural User Interface (NUI) that does not touch the device based on the user interface (UI) of the smart device used in the kitchen. In this method, we use the image processing technology to recognize the user's hand gesture using the camera attached to the device and apply the recognized hand shape to the interface. The gestures used in this study are proposed to gesture according to the user's context and situation, and 5 kinds of gestures are classified and used in the interface.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.221-228
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• 2010

External bonding of carbon fiber reinforced polymer (CFRP) sheets has been widely accepted as a popular method for strengthening of deteriorated RC structures. The long-term behavior of CFRP-strengthened RC structure is often affected by that of the interface between CFRP sheets and concrete. This study aims at applying a viscoelastic model to describe the creep behaviour of the adhesive layer bonding CFRP sheet to concrete, the CFRP-concrete interface. Reviews of available models on concrete creep behavior have been first carried out and then new FE analysis model is proposed. The proposed FE analysis model based on the maxwell model has been verified by previous experimental results. It is shown that the creep effect of interfacial adhesive layer is very important on the long-term behavior of concrete structures strengthened with CFRP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.400-403
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• 2021

Algorithms for predicting the optimal route of vehicles are being actively sudied with the recent development of autonomous driving technology. Companies such as SK, Kakao, and Naver provide services that navigate the optimal route. They predicts the optimal path with information from the users in real time. However, they can predict the optimal route, but not optimal lane route. We proposes a system that navigates the optimal lane path with coordinates data from vehicles using Lidar sensor. The proposed method is a system that guides smooth lanes by acquiring time series coordinate data of a vehicle after performing the Lidar-based object detection method. we demonstrates the performance using actual acquired data from the experimental results.