• 한국지반신소재학회논문집
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• 제23권2호
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• pp.43-52
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• 2024

최근 이상기후로 인한 급경사지 붕괴 위험이 증가되고 있으며, 급경사지 붕괴 위험의 사전 예측 및 경보 전파가 이루어지지 않아 인명과 재산 피해가 발생할 수 있다. 본 논문에서는 급경사지의 상태를 평가하기 위해 IoT 센서와 AI 기반 카메라를 융합한 급경사지 분석 시스템을 개발하였다. 시스템을 개발하기 위하여 급경사지 지반조건을 고려한 계측센서 하드웨어 및 펌웨어 설계, AI 기반 영상 분석 알고리즘 설계, 그리고 예·경보 솔루션 및 시스템 제작을 수행하였다. IoT 센서의 데이터와 AI 카메라 영상 분석을 통해 센서 데이터의 오차를 최소화하고, 데이터의 신뢰성을 향상시키고자 하였다. 또한 실제 급경사지에 적용하여 정확도(신뢰도)를 평가하였다. 그 결과, 센서 계측 오류는 0.1° 이내로 유지되었으며 계측 데이터의 전송률은 95%이상이었다. AI 기반의 영상 분석 시스템은 야간에도 부분 인식률 99%의 높은 성능을 나타내었다. 본 연구결과는 다양한 사회간접자본(SOC) 시설의 급경사지 상태 분석 및 스마트 유지관리 분야에도 적용할 수 있을 것으로 판단된다.

• 한국전산구조공학회논문집
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• 제18권1호
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• pp.93-99
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• 2005

최근, 제철소, 원자력 및 수${\cdot}$화력 발전소 등 주요 기간설비에 있어서 해당 구조물, 관련 장비들의 노후화에 따른 고장진단, 수리보수, 안전성 평가와 잔여 수명 예측을 통한 수명연장에 관련된 요구가 높아지고 있다. 손상발생 시나리오의 구축, 정밀해석기법의 확립, 위험성 혹은 신뢰성 평가기술 개발 등에 관한 연구가 이러한 요구를 반영하여 활발하게 수행되고 있다. 본 연구에서는 구조물의 안전성 평가분야에서 가장 활발하게 사용되는 유한요소해석기술을 이용하여 제철설비 구조물의 안전성을 평가하는 절차를 개발하고 실제 가동 중인 고로를 대상으로 적용하여 유용성을 검토하였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.539-542
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• 2003

A motor is the workhorse of our industry. The issues of preventive and condition-based maintenance, online monitoring, system fault detection, diagnosis, and prognosis are of increasing importance. Different internal motor faults (e.g., inter-turn short circuits, broken bearings, broken rotor bars) along with external motor faults (e.g., phase failure, mechanical overload, blocked rotor) are expected to happen sooner or later. This paper introduces the fault detection technique of induction motors based upon the stator current. The fault motors have rotor bar broken or rotor unbalance defect, respectively. The stator currents are measured by the current meters and stored by the time domain. The time domain is not suitable to represent the current signals, so the frequency domain is applied to display the signals. The Fourier Transformer is used for the conversion of the signal. After the conversion of the signals, the features of the signals have to be extracted by the signal processing methods like a wavelet analysis, a spectrum analysis, etc. The discovered features are entered to the pattern classification model such as a neural network model, a polynomial neural network, a fuzzy inference model, etc. This paper describes the fault detection results that use wavelet decomposition. The wavelet analysis is very useful method for the time and frequency domain each. Also it is powerful method to detect the features in the signals.

• 한국환경복원기술학회지
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• 제8권2호
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• pp.83-89
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• 2005

The historical changes of seeding work in Japan, the typical slope revegetation method, is possible to divide into five periods as follows; 1) The early period after creation(1927-1948) 2) The spreading period of modern revegetation work with manpower(1947-1958) 3) The spreading period of rapid revegetation technique using exotic grasses with machineries(1959-1985${\dots}$) 4) The spreading period of rapid reforestation technique by fast growing species mainly using leguminous shrub species(1986-1995${\dots}$) 5)The developing period of nature restoration technique using endemic arborous species(1996-) The evaluation basis of vegetated condition after slope seeding has been described to a official guide book, "The Standards of Slope Stabilizing Works" It was mainly revised three times after first edition in 1972, and also the point of evaluation basis changed from the vegetation coverage to the density of woody plant through the 3rd period and the 4th period Recently main purpose of slope seeding has been developing from the erosion protection to the nature restoration in the current of the 5th period, and "The tentative guidelines of slope nature restoration" was announced by The Slope Revegetation Section of Japanese Society of Revegetation Technology in 2004. It was proposed the planning techniques of using suitable seeds/plants based on the preservation level at the real each construction sites Consequently, at present the importance of advanced monitoring methods for vegetation maintenance and plant sociologic survey to evaluate the plant succession is increasing.

• Structural Monitoring and Maintenance
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• 제2권1호
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• pp.19-34
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• 2015

One of the main causes of a limited use of nondestructive evaluation (NDE) technologies in bridge deck assessment is the speed of data collection and analysis. The paper describes development and implementation of the RABIT (Robotics Assisted Bridge Inspection Tool) for data collection using multiple NDE technologies. The system is designed to characterize three most common deterioration types in concrete bridge decks: rebar corrosion, delamination, and concrete degradation. It implements four NDE technologies: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW) method. The technologies are used in a complementary way to enhance the interpretation. In addition, the system utilizes advanced vision to complement traditional visual inspection. Finally, the RABIT collects data at a significantly higher speed than it is done using traditional NDE equipment. The robotic system is complemented by an advanced data interpretation. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. This paper concentrates on the validation and field implementation of two NDE technologies. The first one is IE used in the delamination detection and characterization, while the second one is the USW method used in the assessment of concrete quality. The validation of performance of the two methods was conducted on a 9 m long and 3.6 m wide fabricated bridge structure with numerous artificial defects embedded in the deck.

• 지질공학
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• 제20권1호
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• pp.1-12
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• 2010

본 연구에서는 인천 해안 LPG공동의 수리화학적 안정성을 평가하기 위해 공동 유출수 및 주변 지하수에 대한 수리지구화학적 및 미생물학적 특성을 평가하였다. 수질특성을 파악하기 위하여 2007년 2월, 5월, 8월, 10월에 걸쳐 시료채취 및 수질분석을 실시하였다. 프로판공동 지하수의 경우 pH는 8.1~12.4의 높은 값을 보였으며 이는 공동건설 및 관측정설치에 사용된 시멘트 그라우팅 물질의 용해영향으로 사료된다. 전기전도도는 시료채취 시기별로 큰 차이를 보였으며, 음의 산화환원전위는 유출수 및 지하수가 환원환경에 있음을 지시하였다. 수질분석결과 유출수 및 지하수의 수질유형은 모두 Na-Cl type으로 나타났으며 이는 해수의 영향으로 판단된다. 호기성세균, 혐기성세균, 점액질세균, 황산환원세균 모두 500 CFU/mL 미만으로 낮은 값을 보였으며 급격한 미생물 성장은 관찰되지 않았다. 현재로선 공동 운영에 지장을 주는 특이적 수리화학적 현상이 발견되지는 않았으나 지속적인 모니터링이 필요하다.

• Weed & Turfgrass Science
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• 제4권1호
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• pp.65-70
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• 2015

영국갯끈풀(Spartina anglica)은 영국 남부해안 원산의 다년생 염생 잡초로, 2012년 강화도 동막 해변에서 분포가 최초로 확인되었다. 이에 분포 및 확산실태를 보고하며 식별을 위한 식물학적 특성을 제시하였다. Spartina 속은 중국을 포함한 세계 여러 나라에 도입되어 생태공학적 측면의 장점이 인정되었으나, 갯벌을 단일 초지화시키면서 염습지의 생태적 기능을 상실시키는 침입성이 강한 식물로 알려졌고, 제거가 쉽지 않아 관리에 어려움을 겪고 있다. 한국의 서해안 갯벌에서 출현한 영국갯끈풀의 확산은 국내 갯벌 생태계에 심각한 위협을 초래할 수 있으므로 적극적인 제거방안 수립과 지속적인 관찰이 필요하다.

• 대한장애인치과학회지
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• 제5권1호
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• pp.18-22
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• 2009

A 26-year-old female patient with Down syndrome visited to recieve dental treatment under gnenral anesthesia 6 years ago. The patient had difficulties in oral examination, radiograph taking and laboratory test. The patient had congenital heart disease and medical consultation based on the echocardiography was provided by a cardiologist indicating that the patient could tolearte general anesthesia during dental treatment. And two times of general anesthesia were administered during a dental treament with the interval of 3 years and no postoperpative complicaton was reported. At the third dental operation, the patient had a relatively good condition and her prescreening test revealed no abnormalities. Without further consultation with a cardiologist, general anesthesia was administered to the patient. Anaesthesia was based on thiopental and ventilation of desflurane and $N_2O$ in oxygen via an endotracheal tube with an appropriate monitoring. During the maintenance of anesthesia, the blood pressure of the patient started to drop and the oxygen saturation also began to decrease. Consequently, the proceding operation was discontinued and also inhalation anesthesia was ceased. As the patient was recovered from anesthesia, her systemic conditions were alleviated. After the complete recovery of the patient, she visited the cardiologist, and the cardiologic test revealed her severe right ventricular dilatation. In the anesthesia of patients with congenital heart disease, information on their systemic conditions needs to be undated from the medical consultation, which assures the safety of treatment.

• 인간식물환경학회지
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• 제23권3호
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• pp.333-345
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• 2020

Background and objective: The purpose of this study was to provide basic data on trees that can be used for planting design and construction for permanently shaded areas by grasping the growth status of trees according to the daylight conditions of the outdoor spaces of apartment complexes. Methods: On the recently completed apartment complexes, daylight conditions were analyzed by using daylight simulations utilizing Solar Access Analysis of Ecotect Analysis. With a criteria for assessment of tree condition, the defect rate of trees planted in permanently shaded areas and green spaces with good daylight conditions was analyzed to suggest trees applicable to permanently shaded areas. The first tree survey was conducted from November 18, 2019 to February 15, 2020, focusing on trees planted in permanently shaded areas, and the second tree survey of all the trees planted on the study sites including permanently shaded areas was conducted from March 16 to March 30, 2020. Results: Evergreen trees which are classified as shade intolerant trees including Pinus densiflora, Thuja occidentalis, and Abies holophylla showed a higher defect rate of trees among the trees planted in permanently shaded areas. Taxus cuspidata, Zelkova serrata, Cornus kousa, Chionanthus retusus and Acer palmatum which are classified as shade tolerant trees and shade moderate tolerance trees seemed to be able to be used in the plant design of permanently shaded areas in apartment complexes because the trees showed good growth and a low tree defect rate. In addition, although it was excluded from the analysis due to a small number of samples, Sorbus commixta and Prunus cerasifera var. atropurpurea also can be used for planting in permanently shaded areas. Conclusion: The daylight simulation technique used to analyze permanent shaded areas in this study can be used as an analysis tool considering the daylight environment at the stages of design and construction, and additional research will be required to analyze tree growth according to daylight conditions through data accumulation and monitoring by managing records throughout the entire life cycle of trees in the process of planting and maintenance.

• 대한토목학회논문집
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• 제43권3호
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• pp.297-308
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• 2023

구조물의 변위는 안전성 및 성능 평가에 있어서 가장 중요한 요소 중의 하나로서 교량의 안전진단 및 유지관리에 활용하기 위해 외력에 의한 변위를 측정한다. 이러한 변위는 일반적으로 LVDT, 레이저 또는 GNSS를 이용하여 측정하고 있지만 교량의 환경조건 또는 비용적 측면에서 문제점을 가지고 있다. 따라서 본 연구에서는 이러한 문제점을 해결하기 위해 경사계에 의한 회전각 계측데이터를 이용하여 변위를 산정하였으며 알고리즘 검증을 위해 모형시험 및 현장시험을 수행하였다. 그 결과 본 연구에서 제시된 알고리즘을 통해 케이블교량의 차량하중 및 온도하중에 의한 수직변위를 적절하게 산정할 수 있었다. 따라서 차량재하시험에 의한 변위 측정 또는 장기적인 변위 모니터링에 본 연구의 변위 산정 알고리즘이 활용될 수 있을 것으로 기대된다.