• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1171-1181
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• 2014

Different power quality (PQ) disturbance sources can have major impacts on the power supply grid. This study proposes, for the first time, an early warning approach to identifying PQ problems and providing early warning prompts based on the monitored data of PQ disturbance sources. To establish a steady-state power quality early warning index system, the characteristics of PQ disturbance sources are analyzed and summed up. The higher order statistics anomaly detection (HOSAD) algorithm, based on skewness and kurtosis, and hierarchical power quality early warning flow, were then used to mine limit-exceeding and abnormal data and analyze their severity. Cases studies show that the proposed approach is effective and feasible, and that it is possible to provide timely power quality early warnings for limit-exceeding and abnormal data.

• 한국콘텐츠학회논문지
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• 제9권12호
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• pp.504-514
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• 2009

최근 문화재나 시설물 관리를 위한 화재 감시 응용 시스템에 대한 요구가 증대되고 있다. 이러한 화재 감시 시스템은 화재 상황을 대처할 수 있도록 지원함으로써 피해규모를 축소시킬 수 있다. 그러나 기존 시스템은 일정 주기로 화재 감시를 수행함으로써 화재 판단을 지연시키는 단점이 존재한다. 또한 감시 상황을 확인 할 수 있는 사용자 인터페이스를 제공하지 않는다. 따라서 이러한 두 가지 문제점을 해결하기 위하여 첫째, 조기 위험상황 경보를 위해 새로운 화재 판단 알고리즘(Early Fire Detection Algorithm)을 제안한다. 이는 데이터 분포를 기반으로 하여 화재 판단 시작 주기를 동적으로 설정하기 때문에, 화재 판단 시간 측면에서 기존 알고리즘 보다 우수하다. 둘째, 제안하는 화재 판단 알고리즘을 통하여 사용자 인터페이스를 제공하는 화재 감시 응용 시스템을 개발한다. 마지막으로 성능 실험을 통해, 개발된 시스템이 다양한 화재 상황에서 조기 위험상황 경보를 위해 활용될 수 있음을 보인다.

• 동력기계공학회지
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• 제20권2호
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• pp.66-72
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• 2016

As a method to improve the equipment reliability, early warning researches that can be detected fault symptom of an equipment at an early stage are being performed out among developed countries. In this paper, when abnormal signal is input to actual normal signal of a pump, early detection studies on pump's fault symptom were carried out with auto-associative kernel regression as an advanced pattern recognition algorithm. From analysis, correlations among power of motor driving pump, discharge flow of pump, power output of pump, and discharge pressure of pump are exited. When the abnormal signal is input to one of those normal signals, the other expected values are changed due to the influence of the abnormal signal. Therefore, the fault symptom of pump through the early-warning index is able to detect at an early stage.

• 종양간호연구
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• 제12권1호
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• pp.52-60
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• 2012

Purpose: This study is to determine knowledge about early detection and risk perception of cancer according to taking cancer screening tests in the general population. Methods: The participants were 151 people aged 40 years or older. A questionnaire consisted of knowledge about early detection (warning signs, cancer screening methods, general knowledge for early detection), cancer risk perception and history of cancer screening during past 2 years. Results: The percentages of correct answers were 64.7% in knowledge about warning signs, 73.7% in knowledge of cancer screening tests and 80.1% in general knowledge for early detection. Participants had the highest knowledge about screening methods for stomach cancer and the lowest for liver and colon cancer. The level of risk perception was medium. The participants who participated in cancer screening showed lower risk perception than those who did not. There was no significant relationship between knowledge and performance of cancer screening. The primary reason for not participating in cancer screening was patient's perception of their own health. Conclusion: These results suggest that cancer risk perception can affect the performance of cancer screening and we need to study how to handle this problem. Additionally screening programs should focus on liver cancer and colon cancer.

• Smart Structures and Systems
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• 제23권2호
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• pp.107-122
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• 2019

As one of the most important parameters in structural health monitoring, structural frequency has many advantages, such as convenient to be measured, high precision, and insensitive to noise. In addition, frequency-change-ratio based method had been validated to have the ability to identify the damage occurrence and location. However, building a precise enough finite elemental model (FEM) for the test structure is still a huge challenge for this frequency-change-ratio based damage detection technique. In order to overcome this disadvantage and extend the application for frequencies in structural health monitoring area, a novel method was developed in this paper by combining the cross-model cross-mode (CMCM) model updating algorithm with the frequency-change-ratio based method. At first, assuming the physical parameters, including the element mass and stiffness, of the test structure had been known with a certain value, then an initial to-be-updated model with these assumed parameters was constructed according to the typical mass and stiffness distribution characteristic of shear buildings. After that, this to-be-updated model was updated using CMCM algorithm by combining with the measured frequencies of the actual structure when no damage was introduced. Thus, this updated model was regarded as a representation of the FEM model of actual structure, because their modal information were almost the same. Finally, based on this updated model, the frequency-change-ratio based method can be further proceed to realize the damage detection and localization. In order to verify the effectiveness of the developed method, a four-level shear building was numerically simulated and two actual shear structures, including a three-level shear model and an eight-story frame, were experimentally test in laboratory, and all the test results demonstrate that the developed method can identify the structural damage occurrence and location effectively, even only very limited modal frequencies of the test structure were provided.

• 한국해양학회지:바다
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• 제21권1호
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• pp.44-47
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• 2016

Real-time PCR을 적조출현주의보 발령에 활용하였다. Cochlodinium polykrikoides 적조예보를 위해 $10cells\;mL^{-1}$ 이상에서 적조출현주의보를 발령하였는데 현미경 검경은 저밀도에서 정확도가 낮기 때문에 이를 보완하기 위해 C. polykrikoides 특이적 real-time PCR을 사용하였다. 6월 말경에 C. polykrikoides이 통영, 남해 해역에 저밀도로 광범위하게 출현하였고 2015년 8월 2일 적조출현주의보를 발령하였다.

• 상하수도학회지
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• 제20권6호
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• pp.849-855
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• 2006

Taste and odor (T&O) problems in drinking water supplies caused by eutrophication have become increasingly important because aesthetic qualities are the primary measures by which consumers estimate the quality of their drinking water. In order to overcome T&O problem, it is necessary to early detection method for T&O compounds before these compounds enter to water treatment plant. In this background, a early waming device for T&O compounds was developed and its performance tested under different operating condition. According to the experimental results on the adsorption efficiency of T&O compounds, when the raw water flowrate was 5 mL/min, the optimum stripping time and air flowrate were 5 hrs and 0.5 L/min, respectively. Comparison of activated carbon showed that foreign activated carbon was better than domestic activated carbon in terms of adsorption efficiency.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 사면안정 학술발표회
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• pp.60-76
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• 2000

Early detection in real-time response of slope movements ensures tremendous saving of lives and repair costs from catastrophic disaster Therefore, it is essential to constantly monitor the performance and integrity of slope-stabilizing structures such as Rock bolt, Nail and Pile during or after installation. We developed a novel monitoring system using Fiber Bragg Grating (FBG)sensor. It's advantages are highly sensitivity, small dimension and electro-magnetic immunity. capability of multiplexing, system integrity, remote sensing - these serve real-time health monitoring of the structures. Real-time strain measurement by the signal processing program is shown graphically and it gives a warning sound when the monitored strain state exceeds a given threshold level so that any sign of abnormal disturbance on the spot can be easily perceived.

• 한국가스학회지
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• 제17권2호
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• pp.28-35
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• 2013

대도시 내에 밀집하여 증가하고 있는 대형 복합 건축물은 그 규모와 복잡성으로 인해 유해가스 관련 사고발생시 대형 재난으로의 확대 가능성이 상존한다. 이에 대한 대응책으로, 다종의 유해가스를 감지하는 복합 가스 센서와 이로부터 수집한 정보를 활용한 조기 경보 시스템이 연구되고 있다. 이와 같은 센서 기반 재난 전조 감시 시스템의 효과적인 적용과 운영을 위해서는 적합한 기준이 먼저 마련되어야 한다. 본 연구에서는 유해가스의 감지와 조기 경보 발령을 위한 경보 기준 농도를 제시하고, 각 경보 단계별로 대응 활동과 정보 전파 등 재난 대응 체계를 제안하였다. 재난 감시 기준을 통해 유해가스 관련사고 발생 시 조기에 위험을 감지하여 사고의 경과에 따라 효과적인 대응을 이끌어 낼 수 있다.

• Smart Structures and Systems
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• 제6권4호
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• pp.405-421
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• 2010

This paper proposes a method for early warning of hazard for pipelines. Many pipelines transport dangerous contents so that any damage incurred might lead to catastrophic consequences. However, most of these damages are usually a result of surrounding third-party activities, mainly the constructions. In order to prevent accidents and disasters, detection of potential hazards from third-party activities is indispensable. This paper focuses on recognizing the running of construction machines because they indicate the activity of the constructions. Acoustic information is applied for the recognition and a novel pipeline monitoring approach is proposed. Principal Component Analysis (PCA) is applied. The obtained Eigenvalues are regarded as the special signature and thus used for building feature vectors. One-class Support Vector Machine (SVM) is used for the classifier. The denoising ability of PCA can make it robust to noise interference, while the powerful classifying ability of SVM can provide good recognition results. Some related issues such as standardization are also studied and discussed. On-site experiments are conducted and results prove the effectiveness of the proposed early warning method. Thus the possible hazards can be prevented and the integrity of pipelines can be ensured.