• 한국토양비료학회지
• /
• 제50권5호
• /
• pp.336-344
• /
• 2017

The soil water characteristics curve (SWCC) represents the relation between soil water potential and soil water content. The shape and range of SWCC according to the relation could vary depending on soil characteristics. The objective of the study was to estimate SWCC depending on soil types and layers and to analyze the trend among them. To accomplish this goal, the unsaturated three soils were considered: silty clay loam, loam, and sandy loam soils. Weighable lysimeters were used for exactly measuring soil water content and soil water potential. Two fitting models, van Genuchten and Campbell, were applied. Two models entirely fitted well the measured SWCC, indicating low RMSE and high $R^2$ values. However, the large difference between the measured and the estimated was found at the 30 cm layer of the silty clay loam soil, and the gap was wider as soil water potential increased. In addition, the non-linear decrease of soil water content according to the increase of soil water potential tended to be more distinct in the sandy loam soil and at the 10 cm layer than in the silty clay loam soil and at the lower layers. These might be seen due to the various factors such as not only pore size distribution, but also cracks by high clay content and plow pan layers by compaction. This study clearly showed difficulty in the estimation of SWCC by such kind of factors.

• International Journal of Automotive Technology
• /
• 제6권2호
• /
• pp.107-117
• /
• 2005

A distributed hardware-in-the-loop simulation (HILS) platform is developed for designing an automotive engine control system. The HILS equipment consists of a widely used PC and commercial-off-the-shelf (COTS) I/O boards instead of a powerful computing system and custom-made I/O boards. The distributed structure of the HILS system supplements the lack of computing power. These features make the HILS equipment more cost-effective and flexible. The HILS uses an automatic code generation extension, REAL-TIME WORKSHOP$^{ (RTW$^{) of MATLAB$^{ tool-chain and RT-LAB$^{, which enables distributed simulation as well as the detection and generation of digital event between simulation time steps. The mean value engine model, which is used in control design phase, is imported into this HILS. The engine model is supplemented with some I/O subsystems and I/O boards to interface actual input and output signals in real-time. The I/O subsystems are designed to imitate real sensor signals with high fidelity as well as to convert the raw data of the I/O boards to the appropriate forms for proper interfaces. A lot of attention is paid to the generation of a precise crank/ earn signal which has the problem of quantization in a conventional fixed time step simulation. The detection of injection! command signal which occurs between simulation time steps are also successfully compensated. In order to prove the feasibility of the proposed environment, a simple PI controller for an air-to-fuel ratio (AFR) control is used. The proposed HILS environment and I/O systems are shown to be an efficient tool to develop various control functions and to validate the software and hardware of the engine control system.

• 전자공학회논문지
• /
• 제52권7호
• /
• pp.153-161
• /
• 2015

본 논문에서는 사회적 약자(노약자, 장애인 등)들의 사회 경제적 삶의 질 향상을 위한 기술개발(Quality of Life Technology, QoLT)의 일환으로, 다양한 실내외 환경에 대해서 안정적이고 안전한 주행이 가능한 스마트 휠체어 시스템을 개발하고, 이를 효과적으로 운영하기 위한 주행 프레임워크를 제안한다. 특히, 휠체어 탑승자(장애인, 노약자)의 인지/조작능력 부족에 따른 자동/수동 주행 시 편의성과 안전성을 보장하기 위해, 먼저 환경에 최적화된 센서들을 기반으로 사용자 중심의 스마트 휠체어 시스템을 개발하고, 다양한 주행 환경의 변화에 실시간 대응은 물론, 탑승시 안정성을 보장하기 위한 계층적 구조의 주행 프레임워크를 제안, 적용함으로써 보다 효과적인 운영이 가능하도록 하였다. 제안된 방법들에 대한 다양한 실험들을 통해 개발된 스마트 휠체어 시스템과 주행 시스템에 대한 안전성은 물론 효율성을 증명, 확인할 수 있었다.

• 농업생명과학연구
• /
• 제51권1호
• /
• pp.205-212
• /
• 2017

경운기 시뮬레이터 운전자가 가상환경에서 교육에 몰입할 수 있도록 현실세계에 가상 물체를 겹쳐 보여주는 증강 현실 기술을 구현하였다. 3D 카메라 입력 장치로부터 초당 30 frame 이상 속도로 경운기 모의 운전 장치의 영상을 획득한다. 획득된 현실 영상을 크로마키 처리하여 가상 현실과 결합하였다. RGB 영상의 HSI 변환 실험결과 색상 최대값 0.52, 최소값 0.153, 채도 최대값 0.57, 최소값 0.16, 명도 최대값 1, 최소값 0.12이 크로마키 처리를 위해 최적값이었다. 본 연구에서는 키패드를 이용하여 크로마키 처리된 현실 영상의 위치를 전 후 상 하 좌 우를 버튼으로 조정하여 초기 결합위치를 조정할 수 있고 최종 조정된 값은 저장하여 유지 관리되도록 하였다. 이를 토대로 초당 30프레임 이상의 속도로 가상현실과 크로마키 처리 영상을 결합한 증강현실 구현이 가능함을 보였다.

• PNF and Movement
• /
• 제20권3호
• /
• pp.451-459
• /
• 2022

Purpose: Temporomandibular disorder (TMD) is a common musculoskeletal problem that causes pain in and disability of masticatory muscles, the temporo-mandibular joint (TMJ), and related structures. The purpose of this study was to compare pressure pain thresholds (PPTs) of masticatory muscles, cervical ranges of motion (ROM), and pelvic mobility during gait of subjects with or without TMD. Methods: In this study, pain thresholds and changes in the mobility of the cervical vertebrae and pelvis were measured in 25 patients with TMD and 25 healthy controls. Using a pressure algometer, the pressure pain thresholds (PPTs) of the masseter and temporalis muscles were measured in both groups. A gyroscope sensor with a mobile application was used to determine cervical ROM in the frontal and sagittal planes. A 3D-motion analysis system was used to evaluate pelvic mobility in the sagittal, frontal, and transverse planes during gait. Results: The TMD group showed significantly decreased PPTs of masseter and temporalis muscles compared with the control group (p < 0.05). Cervical ROM in flexion, extension, and lateral bending were significantly decreased in the TMD group compared with the control group (p < 0.05). In addition, antero-posterior pelvic tilt was significantly decreased in the TMD group (p < 0.05). Conclusion: The results of the current study suggest that there are close anatomical and functional relationships between TMD and muscle chains related to the cervical spine and pelvis. Therefore, more comprehensive body posture assessments, especially of painful areas, should be undertaken when studying TMD patients.

• 한국전문물리치료학회지
• /
• 제30권1호
• /
• pp.15-22
• /
• 2023

Background: Delivery workers repeatedly get in and out of trucks and walk or run to deliver packages during work. Iliotibial band syndrome (ITBS) is a well-known non-traumatic overuse injury of the lateral side of the knee caused by frequent knee flexion and extension. Hip muscle strength is among the factors that prevent lower extremity injuries. Although many studies have examined the relationship between ITBS and hip muscle strengths, there was no study comparing hip muscle strength and ratio between delivery workers with and without ITBS. Objects: This study aimed to compare hip muscle strength and hip internal/external rotator and adductor/abductor strength ratios between delivery workers with and without ITBS. Methods: Fourteen delivery workers with ITBS matched inclusion criteria in the present study among 20 participants. Because total sample size was required 28 subjects by G*power program (ver. 3.1.9.4; University of Trier), 14 delivery workers without ITBS were recruited. Hip muscle strengths were measured in a side-lying position using a Smart KEMA pulling sensor (KOREATECH Co. Ltd.). An independent t-test was used to compare hip muscle strengths and hip internal/external rotator and hip adductor/abductor strength ratios between delivery workers with and without ITBS. Results: The adductor/abductor strength ratio was significantly greater in delivery workers without ITBS than in those with ITBS (p < 0.05). The strengths of the hip abductor, hip adductor, hip internal rotator, hip external rotator, and the ratio of internal/external rotator strengths were not significantly different between the delivery workers with and without ITBS (p > 0.05). Conclusion: This study's findings showed that delivery workers with ITBS had significantly lesser adductor/abductor strength ratio, while the strengths of the hip abductor and adductor muscles did not differ significantly. These results suggest that adductor/abductor strength ratio should be considered when evaluating and treating ITBS in delivery workers.

• 한국전문물리치료학회지
• /
• 제30권2호
• /
• pp.144-151
• /
• 2023

Background: The gluteus maximus (GM) muscle comprise the lumbo-pelvic complex and is an important stabilizing muscle during leg extension. In patients with low back pain (LBP) with weakness of the GM, spine leads to compensatory muscle activities such as instantaneous increase of the erector spinae (ES) muscle activity. Four-point kneeling arm and leg lift (FKALL) is most common types of lumbopelvic and GM muscles strengthening exercise. We assumed that altered hip position during FKALL may increase thoraco-lumbar stabilizer like GM activity more effectively method. Objects: The purpose of this study was investigated that effects of the three exercise postures on the right-sided GM, internal oblique (IO), external oblique (EO), and multifidus (MF) muscle activities and pelvic kinematic during FKALL. Methods: Twenty eight healthy individuals participated in this study. The exercises were performed three conditions of FKALL (pure FKALL, FKALL with 120° hip flexion of the supporting leg, FKALL with 30° hip abduction of the lifted leg). Participants performed FKALL exercises three times each condition, and motion sensor used to measure pelvic tilt and rotation angle. Results: This study demonstrated that no significant change in pelvic angle during hip movement in the FKALL (p > 0.05). However, the MF and GM muscle activities in FKALL with hip flexion and hip abduction is greater than pure FKALL position (p < 0.001). Conclusion: Our finding suggests that change the posture of the hip joint to facilitate GM muscle activation during trunk stabilization exercises such as the FKALL.

• 대한원격탐사학회지
• /
• 제36권6_2호
• /
• pp.1509-1521
• /
• 2020

다목적실용위성(KOMPSAT-3A: Korea Multi-Purpose Satellite 3A)으로부터 산출된 지표 반사도 성과의 검정 작업을 위하여 분광 반사도 측정값을 제공하고 있는 포털인 Radiometric Calibration Network(RadCalNet)에서 제공하는 4 개의 사이트 자료 중에서 중국 바오터우(Baotou: BTCN) 데이터를 이용한 실험을 수행하였다. 실험을 위한 반사도 성과는 대기 반사도와 지표 반사도를 일괄적으로 처리할 수 있도록 재설계하고 구현한 오픈소스 Orfeo ToolBox(OTB)의 확장 프로그램(Extension)을 이용하여 생성하였다. 절대 대기 보정에 적용되는 두 가지의 센서 모델 변수를 고려하여 2016년, 2017년, 2018년 자료 1개씩 총 3개의 영상 자료를 실험에 적용하였다. 한편 각각 USGS LaSRC 알고리즘과 SNAP Sen2Cor 프로그램을 이용하여 Landsat-8과 Sentinel-2B 영상정보로부터 산출한 반사도 성과와의 비교 검증 작업을 수행하여 센서 별 차이를 확인하고자 하였다. 대기 반사도와 지표 반사도를 대상으로 절대 대기 보정을 위한 필수 입력 값인 Gain과 Offset에 대한 센서 모델 변수 값을 적용한 결과로, 2019년에 발표된 변수 값을 사용한 성과에 비하여 2017년 변수 값을 사용한 성과가 RadCalNet BTCN 자료에 비교적 잘 부합되는 것으로 나타났다. RadCalNet BTCN 자료를 기준으로 KOMPSAT-3A 영상정보의 지표 반사도 성과와의 차이는 밴드 별로 B 밴드(-0.031 ~ 0.034), G 밴드(-0.001 ~ 0.055), R 밴드(-0.072 ~ 0.037), NIR 밴드(-0.060 ~ 0.022)로 일치도가 높은 것으로 나타났고, Landsat-8 영상과 Sentinel-2B 영상의 지표 반사도의 경우도 KOMPSAT-3A 영상의 지표 반사도 성과의 정확도와 유사한 수준인 것으로 나타났다. 이번 연구 결과는 고해상도 위성에서 지표 반사도 값에 대한 분석 대기 데이터(Analysis Ready Data: ARD) 적용 가능성을 확인한 것에 의미가 있다.

• 천문학회보
• /
• 제40권1호
• /
• pp.54.3-54.3
• /
• 2015

To probe the star formation in local and early Universe, the NISS with a capability of imaging spectroscopy in the near-infrared is being developed by KASI. The main scientific targets are nearby galaxies, galaxy clusters, star-forming regions and low background regions. The off-axis optical design of the NISS with 15cm aperture was optimized to obtain a wide field of view (FoV) of $2deg.{\times}2deg.$ as well as a wide spectral coverage from 0.9 to $3.8{\mu}m$. The opto-mechanical structure was designed to be safe enough to endure in both the launching condition and the space environment. The dewar will operate $1k{\times}1k$ infrared sensor at 80K stage. The NISS will be launched in 2017 and explore the large areal near-infrared sky up to $200deg.^2$ in order to get both spatial and spectral information for astronomical objects. As an extension of the NISS, KASI is planning to participate in a new small space mission together with NASA. The promising candidate, SPHEREx (Spectro-Photometer for the History of the Universe Epoch of Reionization, and Ices Explorer) is an all-sky survey satellite designed to reveal the origin of the Universe and water in the planetary systems and to explore the evolution of galaxies. Though the survey concept is similar to that of the NISS, the SPHEREx will perform the first near-infrared all-sky imaging spectroscopic survey with the wider spectral range from 0.7 to $5{\mu}m$ and the wider FoV of $3.5deg.{\times}7deg.$ Here, we report the current status of the NISS and introduce new mission for the near-infrared imaging spectroscopic survey.

• 대한원격탐사학회지
• /
• 제36권2_1호
• /
• pp.167-178
• /
• 2020

2015년 발사된 이후 KOMPSAT-3A 영상정보가 여러 분야에서 활용되고 있다. 그러나 실제 육상 환경의 분석에 필요한 지표 반사도를 얻을 수 있는 도구 개발이 이루어지지 않아서 식생 지수 산정 등과 같이 이러한 자료를 적용하는 과학적 분석과 응용 분야의 확산에는 한계가 있었다. 지표 반사도는 절대 대기 보정 처리 과정을 수행하여 얻어지는 성과물이다. 이 연구에서는 OTB 오픈 소스 확장 프로그램으로부터 KOMPSAT-3A 영상정보의 대기 반사도와 지표 반사도를 구하고, 국제 검보정 포털 RadCalNet에서 제공하는 대기 반사도와 지표 반사도 현장 측정 자료를 이용하여 정확도를 비교 검증하고자 한다. 또한 같은 지역의 Landsat-8 OLI 영상으로부터 지표 반사도를 구하고 비교 검증 실험에 같이 적용하였다. 검증 실험 결과로 KOMPSAT-3A 영상의 대기 반사도는 같은 분광대역에 해당하는 RadCalNet 자료의 평균값과 비교했을 때 0.00에서 1.00까지의 범위에서 최대 ± 0.02 차이가 보이는 것을 확인할 수 있었다. KOMPSAT-3A 영상의 지표 반사도 산출 결과는 RadCalNet 자료와 0.02에서 0.04까지의 차이 값을 갖는 높은 일치도를 보이는 것으로 나타났다. 이 결과들은 KOMPSAT-3A 영상의 분석대기자료(Analysis Ready Data)로서의 활용 가능성을 증가시키는 기본 자료로 사용할 수 있다. 또한 이 연구에서 개발된 도구와 연구 방법은 향후 국토, 농업, 산림 활용을 위한 차세대 중형 위성 영상자료의 각 센서 모델에 맞는 확장 프로그램 개발과 검증에도 적용이 가능할 것으로 생각한다.