• E2M - 전기 전자와 첨단 소재
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• 제11권11호
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• pp.1-8
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• 1998

This paper presents an arificial neuro-fuzzy technique based prtial discharge (PD) pattern classifier to power system application. This may require a complicated analysis method employ -ing an experts system due to very complex progressing discharge form under exter-nal stress. After referring briefly to the developments of artificical neural network based PD measurements, the paper outlines how the introduction of new emerging technology has resulted in the design of a number of PD diagnostic systems for practical applicaton of residual lifetime prediction. The appropriate PD data base structure and selection of learning data size of PD pattern based on fractal dimentsional and 3-D PD-normalization, extraction of relevant characteristic fea-ture of PD recognition are discussed. Some practical aspects encountered with unknown stress in the neuro-fuzzy techniques based real time PD recognition are also addressed.

• 콘크리트학회논문집
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• 제18권2호
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• pp.293-298
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• 2006

The reinforced concrete(RC) structures strengthened with fiber reinforced plastic(FRP) has been accepted by the construction engineering community for rehabilitation. FRP composites can present many advantages like a corrosion resistance, strength-weight ratio, relatively short application time, and cost effectiveness. The beams under design load, however, are cracked and result in degrading the strength. It is difficult to recognize cracks and deflections on the surface of the concrete members retrofitted with FRP through the life cycle. For these reasons, if they result in the effects, which were below the expected strength, we must monitor the state of concrete structures all the time in order to take an appropriate measure. Fiber Bragg Grating(FBG) sensor excel as monitoring of investigating the stress state of the retrofitted beams with FRP. The main objective of this study is to measure strain by experiment and analyze the behavior of RC beams retrofitted with FRP using FBG sensor. The kinds of FRP which were used in research are carbon, glass and improved hybrid FRP(IFRP) that has capacity than any other FRP. Other variables are the length of FRP, the number of sheet.

• Journal of Animal Science and Technology
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• 제66권1호
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• pp.31-56
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• 2024

Pig farming, a vital industry, necessitates proactive measures for early disease detection and crush symptom monitoring to ensure optimum pig health and safety. This review explores advanced thermal sensing technologies and computer vision-based thermal imaging techniques employed for pig disease and piglet crush symptom monitoring on pig farms. Infrared thermography (IRT) is a non-invasive and efficient technology for measuring pig body temperature, providing advantages such as non-destructive, long-distance, and high-sensitivity measurements. Unlike traditional methods, IRT offers a quick and labor-saving approach to acquiring physiological data impacted by environmental temperature, crucial for understanding pig body physiology and metabolism. IRT aids in early disease detection, respiratory health monitoring, and evaluating vaccination effectiveness. Challenges include body surface emissivity variations affecting measurement accuracy. Thermal imaging and deep learning algorithms are used for pig behavior recognition, with the dorsal plane effective for stress detection. Remote health monitoring through thermal imaging, deep learning, and wearable devices facilitates non-invasive assessment of pig health, minimizing medication use. Integration of advanced sensors, thermal imaging, and deep learning shows potential for disease detection and improvement in pig farming, but challenges and ethical considerations must be addressed for successful implementation. This review summarizes the state-of-the-art technologies used in the pig farming industry, including computer vision algorithms such as object detection, image segmentation, and deep learning techniques. It also discusses the benefits and limitations of IRT technology, providing an overview of the current research field. This study provides valuable insights for researchers and farmers regarding IRT application in pig production, highlighting notable approaches and the latest research findings in this field.

• 한국전자거래학회지
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• 제22권2호
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• pp.1-18
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• 2017

오늘날 감정 표현이 서툰 영유아가 처한 극도의 스트레스 상태를 자동적으로 파악하는 것은 영유아의 안전을 위협하며 지속적으로 발생하는 위험 상황의 실시간적인 인지를 위해 반드시 필요한 기술이다. 따라서 본 논문에서는 생체신호를 활용하여 영유아의 스트레스 상태를 분류하기 위한 기계학습 기반의 모델과 생체신호 수집용 스마트 밴드 및 모니터링용 모바일 어플리케이션을 제안한다. 구체적으로 본 연구에서는 영유아의 감정을 나타내는 주요한 요인이 되는 음성 및 심박 데이터의 조합을 활용하여 기존에 널리 알려진 데이터 마이닝 기법을 통해 영유아의 스트레스 상태 패턴을 학습하고 예측한다. 본 연구를 통해 생체신호를 활용하여 영유아의 스트레스 상태 식별을 자동화할 수 있는 가능성을 확인하였으며 나아가서 궁극적으로 영유아의 위험 상황 예방에 활용될 수 있을 것으로 기대된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.442-451
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• 2008

The evaluation of field degree of consolidation on soft clays has been an important problem in geotechnical areas. Monitoring either settlements or pore water pressures has been widely applied in the filed, but occasionally they have some problems. This study addresses the suggestion and application of another method for evaluating the degree of consolidation using shear wave velocities. A research site where soft clay layers were consolidated by surcharging loads was chosen. Laboratory tests were performed to determine the relation between shear wave velocity and effective stress. Field seismic tests were conducted several times during the consolidation of the clay layers. The tests results show that the shear wave velocity increased significantly as clays consolidated. The shear wave velocities at each field stress states were derived from the laboratory results and the degree of consolidation was evaluated by comparing the shear wave velocities obtained by laboratory and field seismic methods. In most stress states, the degree of consolidation evaluated using the shear wave velocity matched well with that obtained from field settlement record, showing the potential of applying the method using shear waves in the evaluation of field degree of consolidation on soft clay deposits.

• Geomechanics and Engineering
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• 제22권1호
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• pp.1-9
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• 2020

This paper presents an investigation of the ground response of a gob-side gateroad suffering mining stress induced by a 21 m-thick coal seam extraction. A field observation, including entry convergence and stress changes monitoring, was first conducted in the tailgate 8209. The observation results of entry convergence showed that, during the adjacent panel 8210 retreating period, the deformation of the gob-side gateroad experienced a continuous increase stage, subsequently, an accelerating increase stage, and finally, a slow increase stage. However, strong ground response, including roof bending deflection, rib extrusion and floor heave, occurred during the current panel 8209 retreating period, and the maximum floor heave reached 1530 mm. The stress changes within coal mass of the two ribs demonstrated that the gateroad was always located in the stress concentrated area, which responsible for the strong response of the tailgate 8209. Subsequently, a hydraulic fracture technique was proposed to pre-fracture the two hard roofs above the tailgate 8209, thus decreasing the induced disturbance on the tailgate. The validity of the above roof treatment was verified via field application. The finding of this study could be a reference for understanding the stability control of the gob-side gateroad in extra thick coal seams mining.

• Ocean and Polar Research
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• 제30권1호
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• pp.109-117
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• 2008

해양환경 건강성 평가에서 바이오마커의 적용은 상대적으로 새로운 분야이다. 국립학술원 및 세계보건기구에 따르면 바이오마커는 노출바이오마커, 영향바이오마커 및 민감바이오마커 등 3가지로 나누어진다. 해양생태계에 대한 환경오염물질의 노출 및 영향을 평가하기 위하여 다음과 같은 바이오마커들이 시험되고 있다: 해독, 산화스트레스, 분해산물, 스트레스 반응, 세포사멸, 물질대사, 신경반응, 생식, 스테로이드 호르몬, 항산화물질, 유전적 변형. 1990년대 초부터 여러 바이오마커 연구그룹들은 해양생물의 건강지수를 개발하여 해양환경의 상태를 평가하기 위한 수단으로 활용해 왔다. 바이오마커 지수는 생물학적 효과에 대한 모니터링활동으로부터 얻어진 자료의 해석에 사용될 수 있다. 본 총설에서는 이제까지 보고된 바이오마커 지수 관련 연구 중 대표적인 건강평가지수(Health assessment Index), 바이오마커 지수(Biomarker Index), 생물영향평가지수(Bioeffect Assessment Index) 및 일반화된 선형모델(Generalized Linear Model) 등의 연구를 요약하였다. 오염된 지역에 서식하는 해양생물의 바이오마커 반응 측정 및 바이오마커 지수 개발은 다양한 측면의 해양생태계 위해성 평가를 위해 고안된 환경모니터링 프로그램에 공헌할 수 있는 정보를 제공해 줄 수 있을 것이다.

• Smart Structures and Systems
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• 제1권4호
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• pp.385-404
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• 2005

The paper presents a model to calculate reinforcement strain using measured crack width in members under applied tension, flexure, and/or shear stress. Crack mapping using a new type of distributed coaxial cable sensors for health monitoring of large-scale civil engineering infrastructure was recently proposed and developed by the authors. This paper shows the results and performance of such sensors mounted on near surface of two flexural beams and a large scale reinforced concrete box girder that was subjected to cyclic combined shear and torsion. The main objectives of this health monitoring study was to correlate the sensor's response to strain in the member, and show that magnitude of the signal's reflection coefficient is related to increases in applied load, repeated cycles, cracking, and reinforcement yielding. The effect of multiple adjacent cracks, and signal loss was also investigated. The results shown in this paper are an important step in using the sensors for crack mapping and determining reinforcement strain for in-situ structures.

• Structural Monitoring and Maintenance
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• 제9권3호
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• pp.259-270
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• 2022

This study explores the use of the recently developed "strain-sensing smart skin" (S⁴) method for noncontact strain measurements on cement-based samples. S⁴ sensors are single-wall carbon nanotubes dilutely embedded in thin polymer films. Strains transmitted to the nanotubes cause systematic shifts in their near-infrared fluorescence spectra, which are analyzed to deduce local strain values. It is found that with cement-based materials, this method is hampered by spectral interference from structured near-infrared cement luminescence. However, application of an opaque blocking layer between the specimen surface and the nanotube sensing film enables interference-free strain measurements. Tests were performed on cement, mortar, and concrete specimens with such modified S⁴ coatings. When specimens were subjected to uniaxial compressive stress, the spectral peak separations varied linearly and predictably with induced strain. These results demonstrate that S⁴ is a promising emerging technology for measuring strains down to ca. 30 𝜇𝜀 in concrete structures.

• 한국수자원학회논문집
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• 제36권5호
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• pp.839-849
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• 2003

가뭄은 주요 자연 재해 중의 하나이다. 가뭄 파악을 위하여 주로 강우량과 같은 기상자료를 주요 입력 자료로 활용하여 분석하고 있으나 이러한 기상 자료는 한정된 기상 관측소로부터 얻어진 점자료에 해당된다. 따라서, 기상자료를 이용한 분석에서는 시간적 혹은 공간적으로 원하는 자료의 제공이 원활하게 이루어지지 않을 수 있다. 원격탐사 자료는 가뭄분석을 위하여 기상자료에서 포착할 수 없는 이러한 문제점을 보완하기 위한 자료로 활용될 수 있다. 따라서, 본 연구에서는NOAA 위성에 탑재되어 있는 AVHRR 센서로부터 얻어지는 자료를 이용하여 가뭄 파악을 위한 분석을 실시하였다. 특히 본 연구에서는 NOAA/AVHRR로부터 얻어진 식생지수(NDVI)와 이로부터 얻을 수 있는 식생상태지수(VCI)를 이용하여 가뭄 분석을 실시하였으며, 이들 지수는 가뭄으로부터 기인된 식생 스트레스를 파악하는데 유용하게 이용될 수 있음을 알 수 있었다. 본 연구를 통하여 가뭄에 대한 시간적, 공간적 특성을 파악하는데 위성자료가 유용하게 이용될 수 있음을 알 수 있었으며, VCI를 통하여 가뭄 지역도 작성이 가능함을 보여주고 있다.