• Structural Monitoring and Maintenance
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• v.4 no.3
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• pp.221-236
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• 2017

In this study, the feasibility of vibration-based damage alarming algorithms are numerically evaluated for wind turbine tower structures which are subjected to harmonic force excitation. Firstly, the algorithm of vibration-based damage alarming for the wind turbine tower (WTT) is visited. The natural frequency change, modal assurance criterion (MAC) and frequency-response-ratio assurance criterion (FRRAC) are utilized to recognize changes in dynamic characteristics due to a structural damage. Secondly, a finite element model based on a real wind turbine tower is established in a structural analysis program, Midas FEA. The harmonic force is applied at the rotor level as presence of excitation. Several structural damage scenarios are numerically simulated in segmental joints of the wind turbine model. Finally, the natural frequency change, MAC and FRRAC algorithm are employed to identify the structural damage occurred in the finite element model. The results show that these criteria could be used as promising damage existence indicators for the damage alarming in wind turbine supporting structures.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.1096-1099
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• 2014

스마트폰의 보급률에 맞물려 스마트폰 사용으로 인한 보행자 교통사고가 증가함에 따라 전세계적으로 이에 관한 연구 또한 꾸준히 증가 추세임에도 불구하고 인구대비 스마트폰 보급률이 세계 최고인 국내에서는 이에 대한 연구가 아직 미흡한 실정이다. 본 연구에서는 보행 중 교통사고 중에서 큰 비중을 차지하고 있는 젊은층의 산만 보행에 관해 알아보고자 하였다. 본 연구는 정신과학 분야의 주의 네트워크 연구를 바탕으로 보행자의 안전도 향상은 물론, 스마트폰 이용자의 사용성을 고려한 depth-based alarming 서비스를 제안한다.-본 연구는 스마트폰 애플리케이션을 제작하여 국내 20대 스마트폰 이용자를 대상으로 피험자내 설계로 진행되었고, 보행자의 안전도에 관련한 무선조종 자동차에 대한 반응속도와 충돌여부를 측정하였고, 또한 앱 사용성에 관련한 방해도 및 만족도를 설문을 통해 측정하였다. 본 연구는 위험 상황을 알리는 alarm 을 제공하기 전에 미리 pre-alarm 을 제공하는 depth-based alarming 을 디자인 하였다. 본 연구는 실험을 통해 pre-alarm 제공시 alarm 에 대한 보행자의 반응 속도가 1.446 초 향상됨을 통계적 유의성을 통해 입증함으로써 pre-alarm 을 제공하는 depth-based alarming 서비스의 필요성을 제시한다.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.73-78
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• 2005

A fire is occurring increasingly every you and the damage is bigger in proportion to the number. Therefore a fire is classified as a serious calamity. It is important to evacuate and fight a fire by early Perception. However, if the alarming sound is not perceived when a fire breaks out the damage could be expanded. From this point of view, this study aims to analyse the correlation between alarming sound sources and sound quality parameters through psycho-acoustic experiment using Korean vocabularies extracted by existing study. The sound sources more dangerous, tense and urgent were chosen. The results from this study are as follows: 1. airraid, klaxon2 and S.O.S got a point more than conventional alarming sound.2. correlation coefficient between Loudness(L) and Unbiased Annoyance(UA) was highest with 0.63 md Sharpness(S) and Roughness(R) was -0.40 and Fluctuation Strength(FL) and Tonality(T).

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1721-1723
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• 2002

This paper deals with the analysis of field condition for earth leakage current alarming system in the stage lighting, stage sound stage machinery installation. These analyses of field condition were carried out in accordance with investigating an installation of earth leakage current alarming system with respect to a main line of power source, dimmer, sound equipment, machinery mobile unit equipment and so on. As a result of analyses. The earth leakage current alarming system has been installed only a part of the main line of power source and the probability of places which were installed was less than 50(%). Therefore, it is desirable that the earth leakage current alarming system is installed at places which are suitable, for example, dimmer, each kind machinery etc. in order to prevent electrical hazard.

• Structural Engineering and Mechanics
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• v.54 no.2
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• pp.337-362
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• 2015

This paper presents a feasibility study on structural damage alarming and localization of long-span cable-supported bridges using multi-novelty indices formulated by monitoring-derived modal parameters. The proposed method which requires neither structural model nor damage model is applicable to structures of arbitrary complexity. With the intention to enhance the tolerance to measurement noise/uncertainty and the sensitivity to structural damage, an improved novelty index is formulated in terms of auto-associative neural networks (ANNs) where the output vector is designated to differ from the input vector while the training of the ANNs needs only the measured modal properties of the intact structure under in-service conditions. After validating the enhanced capability of the improved novelty index for structural damage alarming over the commonly configured novelty index, the performance of the improved novelty index for damage occurrence detection of large-scale bridges is examined through numerical simulation studies of the suspension Tsing Ma Bridge (TMB) and the cable-stayed Ting Kau Bridge (TKB) incurred with different types of structural damage. Then the improved novelty index is extended to formulate multi-novelty indices in terms of the measured modal frequencies and incomplete modeshape components for damage region identification. The capability of the formulated multi-novelty indices for damage region identification is also examined through numerical simulations of the TMB and TKB.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.487-491
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• 2007

Recently, rainfall induced hazard has been increased gradually, for example, typhoon Rusa in 2002 and Maemi in 2003. In addition, localized heavy rainfall has been also caused tremendous damage to railroad systems. Measured data from the Meteorological Adminstration sometimes, However, are not in accordance with those of rain gauges in local area, because of its good distance. This study develop automatic alarming software to estimate and prevent these kind of rainfall induced hazards in railroad system with online transportation.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.339-348
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• 2010

As part of preparing for future earthquakes near three LNG receiving terminals located in coastal regions of Korea, acceleration monitoring systems were installed at four free field sites and on a pile foundation beneath a storage tank in a receiving terminal. Several equipments and accessories were devised to successfully install and operate the monitoring system at LNG receiving terminals. Synthetic earthquake-alarming software systems designed for decisionmaking, based on peak ground acceleration computed using the measured data, were developed for rapid response during earthquakes, not only in each local terminal area but also in the central control division. In addition, a framework software linking nationwide data on peak ground accelerations was included in the integrated earthquake alarming system in the central division, for various future applications. The earthquake alarming systems developed in this research for LNG receiving terminals, based on acceleration monitoring, represent a useful framework for industrial facilities located in coastal regions, where geotechnical conditions may show marked spatial variations.

• Journal of IKEEE
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• v.19 no.3
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• pp.311-318
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• 2015

This dissertation proposes method for development technology of voice and SMS(Short Message Service) alarming system based on modbus protocol. The proposed technology is composed of the following 3 stages; hardware development based on microprocessor, development of input and output driver for modem, mp3 decoder, making modbus protocol stack. In the stage of hardware development based on microprocessor, we develop hardware which receives alarm from modbus master and transmit sms message, play mp3. In the stage of development of input / ouput device driver such as modem, mp3 decoder, we develop program which control each devices. In the stage of making modbus protocol stack, voice and sms alarm system is made for receiving alarm via modbus protocol. To evaluate performance of proposed technology, we issued alarm to voice and sms alarming system on purpose. As a result, response speed of detecting alarm was 10.7ms, communication distance was 1.2Km, operating temperature was from $-25^{\circ}C$ to $70^{\circ}C$, we confirmed supporting modbus protocol. And we verified that proposed voice and sms alarming system in the thesis has a performance to be used as an industrial building alarming system.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.157-160
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• 2008

This study analyzed on the area of Samcheok, Kangwondo about forest fire alarming area and enlargement of the area. Then, visible area by unattended watching camera and watchtower for forest fire which were run by Samcheok was cross-checked with geographic information system, and it could be whether effective on watching the area where the forest fire risk was high enough and also it could be expanded to larger forest fire. The result of study, the visible area by watching facilities only holds for 13.4% of the whole forest fire alarming area, but the forest fire can be observed even though it is occurred in small valley because of smoke and all the forest fire have been occurred in daytime. Therefore, it can be determined that watching area will be extended around 50.3% while the observation radii of watching facilities raise by 4km. However, Samcheok has much greater area of mountain area in compared to any other cities or counties, watching facilities should be installed and run additionally for extinguishing the forest fire from the beginning.

• The KIPS Transactions:PartB
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• v.18B no.4
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• pp.213-220
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• 2011

This paper proposes an effective, four-stage smoke detection method based on video that provides emergency response in the event of unexpected hazards in early fire-alarming systems. In the first phase, an approximate median method is used to segment moving regions in the present frame of video. In the second phase, a color segmentation of smoke is performed to select candidate smoke regions from these moving regions. In the third phase, a feature extraction algorithm is used to extract five feature parameters of smoke by analyzing characteristics of the candidate smoke regions such as area randomness and motion of smoke. In the fourth phase, extracted five parameters of smoke are used as an input for a K-nearest neighbor (KNN) algorithm to identify whether the candidate smoke regions are smoke or non-smoke. Experimental results indicate that the proposed four-stage smoke detection method outperforms other algorithms in terms of smoke detection, providing a low false alarm rate and high reliability in open and large spaces.