• Journal of the Korean Society of Safety
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• v.6 no.4
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• pp.34-44
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• 1991

In this study, the general solution of heat balance equation including conductive heat loss were suggested and were determined the constants with the results of experiment in hot tunnel in order to derive the general equation for the response time and to investigate the response time index which represent the characteristics of response of sprinkler head in actual fires. Two types of test were considered, the plunge test, in which the air temperature is represented by a step function, and the ramp test, in which the air temperature increases at a constant rate. As a result, simple equations were derived, which can be predicted the response time for the ramp type fire with the rate of temperature rise and gas velocity, for the plunge type fire with temperature and gas velocity. Also other useful data, such as the effective temperature, time constant, response time index and conduction parameter were obtained.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.46-51
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• 2017

This paper presents classification of domestic fire detector using response time index. Response time is measured using fire detector distributed in Korea, and the response time index is estimated. Plunge test prescribed by FM is conducted to measure response time of fire detector. The detector used to test is fixed temperature type(thermistor and bimetal type) and rate of rise temperature type(thermistor and pneumatic type). The nominal operation temperature of fixed temperature type detector is $70^{\circ}C$ and rate of rise temperature is $15^{\circ}C/min$. The fixed temperature type is measured 7 products, and the rate of rise temperature type is measured 5 products. The results show that in case of fixed temperature type(thermistor) is classified "Quick" or "Standard" and fixed temperature type(bimetal) is not classified. The rate of rise temperature type(thermistor) is classified "Fast" or "Ultra Fast" and the rate of rise temperature type(pneumatic) is classified "Very Fast" or "Ultra Fast". The pneumatic type shows more fast response than thermistor type. Also these results indicate the fixed temperature type(bimetal) is not suitable for early stage fire detection.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.217-227
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• 2013

Objective: The purpose of this study was to analyze 'response time', 'peak response time' and 'overshoot value' for each muscle by applying the EMG signal to the vehicle response in ISO 7401 and to quantify the response of the driver according to vehicle characteristics by comparing vehicle characteristics and muscle responses of the driver. Background: The Open-loop test defined in international standards ISO 7401 is the only method for evaluating the performance of the vehicle. However, this test was focused only on mechanical responses, not driver's ones. Method: One skilled male driver(22 yrs. experience) was participated in this experiment to measure muscle activities of the driver in transient state. Then the seven muscle signals were applied to calculate 'response time', 'peak response time', and 'overshoot value'. Results: In the analyses of the EMG data, the effects of vehicle type and muscle were statistically significant on the 'response time' and 'peak response time'. Also, the effects of vehicle type, muscle, and lateral acceleration level were statistically significant on the 'overshoot value' in this study. According to the analyses of the vehicle motion data, vehicle motion variable(LatAcc, Roll, YawVel) was statistically significant on the 'response time' and vehicle type, vehicle motion variable, and lateral acceleration level were statistically significant on the 'peak response time', respectively. Conclusion: In the analyses of the 'response time' and 'overshoot value', the data of muscle activities(EMGs) was better index that could evaluate the vehicle characteristic and performance than the data of vehicle motion. In case of peak response time, both EMG and vehicle motion data were good index. Application: The EMGs data from a driver might be applicable as index for evaluation of various vehicle performances based on this study.

• Journal of the Korean Society of Safety
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• v.13 no.4
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• pp.59-70
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• 1998

In this study, response time index(RTI) of standard and quick response type sprinkler head are measured and compared through ramp and plunge test in heated wind tunnel. Also discharge rate and water distribution, actual delivered density(ADD), fire test with wood cribs are performed to compare the fire suppression capability and the operation time and temperature between standard and quick response type sprinkler head.

• Korean Journal of Human Ecology
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• v.20 no.1
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• pp.195-203
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• 2011

The purpose of this study was to define the effects of the finger temperature response according to the daily life of college student. For this study, 31 healthy female college students were taken as a subject group. To define the effects of the finger temperature response, housing style, subjective thermal sensations during daily life in the house and domestic working time were surveyed. The finger temperature response items were measured. The results were as follows. Strong, normal and weak group members were divided according to their cold resistance index(RI) 3, 8, 20 people, repectively. Subjective thermal sensations during daily life in the house affects the cold resistance index(p<.01). The cold resistance index(RI) got higher as domestic working time was increased(p<.05, F-value=3.927). The percentage wearing protective gloves during domestic work in the weak group was higher than the normal or strong groups. Subjective sensations during daily life and domestic working time effected the local cold tolerance, living in a comfortable environment continuously can weaken one's cold tolerance.

• Fire Science and Engineering
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• v.7 no.1
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• pp.11-16
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• 1993

Fixed temperature heat detectors that respond to the heat generated in fire plume and alarm when the temperature reaches a specified point, give a great influences to the loss of life and property according to their reaction sensitivity. In this study, hot wind tunnel tests and compartment fire experiments were performed to investigate the response time and temperature of fixed temperature heat detector. As a result, simple equations were derived which can be predicted the response time and temperature of the fixed temperature heat detector for the ramp type fire. Also other useful data, such as the effective temperature, time constant, response time index(RTI) were obtained.

• Structural Engineering and Mechanics
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• v.26 no.3
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• pp.315-341
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• 2007

A sudden change of stiffness in a structure, associated with the events such as weld fracture and brace breakage, will cause a discontinuity in acceleration response time histories recorded in the vicinity of damage location at damage time instant. A new damage index is proposed and implemented in this paper to detect the damage time instant, location, and severity of a structure due to a sudden change of structural stiffness. The proposed damage index is suitable for online structural health monitoring applications. It can also be used in conjunction with the empirical mode decomposition (EMD) for damage detection without using the intermittency check. Numerical simulation using a five-story shear building under different types of excitation is executed to assess the effectiveness and reliability of the proposed damage index and damage detection approach for the building at different damage levels. The sensitivity of the damage index to the intensity and frequency range of measurement noise is also examined. The results from this study demonstrate that the damage index and damage detection approach proposed can accurately identify the damage time instant and location in the building due to a sudden loss of stiffness if measurement noise is below a certain level. The relation between the damage severity and the proposed damage index is linear. The wavelet-transform (WT) and the EMD with intermittency check are also applied to the same building for the comparison of detection efficiency between the proposed approach, the WT and the EMD.

• Journal of the Society of Disaster Information
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• v.11 no.2
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• pp.203-209
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• 2015

The heat detector detects heat in the fire and is an important core element of the automatic fire alarm system used generally for every fire prevention objects. The heat detector is distinguished in spot type and spread type and in spot type, there are differential and thermistor types. These heat detectors give a great influence on the loss of people and property according to the sensitivity of response such as operation time and operation temperature in actual fire and in overseas people apply it for the development of products that can be operated in the early stage of fire including certification, quality management, and comparison standard by introducing response time index through the theory of heat balance that considers the heat loss and ventilation tests. In Korea, the response time index is introduced and used in the head of sprinkler products, but it is not applied to the heat detector at present. It is necessary to introduce the response time index that shows the sensitivity of response of the heat detector the installation standard for the heat detector that the response time index is applied should be different according to the fire weight, danger degree of fire, and shape of buildings. Through this study, it tries to help reduce lives and property of people through the swift warning by installing detectors suitable for the building structure.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.2
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• pp.144-155
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• 1992

A design of a highly stable current-controlled power supply combining the phase-controlled rectifier (PCR), passive filter and active filter is investigated. A digital phase-looked voltage control (PLVC) with a capability of compensating the thyristor firing angles under unvalanced power source is proposed` otherwise the PCR output voltage has low-order subharmonics whose suppression requires a bulky passive filter. The digital PLVC has a fast dynamic characteristics as an inner control loop of the PCR. To suppress further the output ripple, an active filter using a transformer is introduced and its design is described through the frequency domain analysis. An optimal integral, proportional and measurable variable feedback (IPM) controller is designed using the time-weighted performance index based on the time domain analysis. The design method based on the time-weighted performance index gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives good dynamic and static performances.

• Fire Science and Engineering
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• v.10 no.3
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• pp.51-57
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• 1996

반응시간지수(Response Rime Index : RTI)를 사용하여 스프링클러의 열응답(thermal response) 특성을 분류할 수 있다. 반응시간지수는 plunge test에서 균일한 고온의 공기속도의 제곱근과 스프링클러 열감지부의 시정수(time constant)의 곱으로 나타낼 수 있다. 고온의 주위 공기온도에서 스프링클러가 작동하는 시간을 측정하므로서 열감지부의 시정수를 계산할 수 있다. 스프링클러의 RTI가 시정수에 비하여 실험조건에 따른 변화 폭이 적으므로 실제 화재시의 스프링클러 자동시간을 예측하는데에는 RTI가 사용된다. 스프링클러의 작동시간 예측을 위해서는 RTI값과 스프링클러 열감지부 주위의 유속이 필요하며, 유속은 화재의 발열량과 스프링클러가 설치된 구획의 높이로부터 실험식으로 결정된다. 따라서 Plunge test를 이용하여 얻은 스프링클러 열감지부의 기본자료로부터 실화재시의 스프링클러 작동시간을 예측하게 되며, ZONE 모델과 같은 화재 simulation 프로그램과 같이 사용된다면 스프링클러 작동시의 연층의 높이도 예측 가능하게 된다.