• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.97-102
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• 1997

A new method based on the alternating conditional expectation (ACE) algorithm is developed to calculate axial shape index (ASI) for the 3-level excore detector. The ACE algorithm, a type of non-parametric regression algorithms, yields an optimal relationship between a dependent variable and multiple independent variables. In this study, the simple correlation between ASI and excore detector signals is developed using the Younggwang nuclear power plant unit 3 (YGN-3) data without any preprocessing on the relationships between independent variables and dependent variable. The numerical results show that simple correlations exist between the three excore signals and ASI of the core. The accuracy of the new method is much better than those of the current CPC and COLSS algorithms.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.49-59
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• 1997

This study was performed to analyze the purity of technical grade ${\alpha}$-naphthylamine, to establish optimal analytical condition of ${\alpha}$-naphthylamine in urine and to determine the urine sample of workers exposed to ${\alpha}$-naphthylamine. The purity of technical grade ${\alpha}$-naphthylamine were $96.5{\pm}2.38%$, $94.1{\pm}0.97%$, $97.0{\pm}0.02%$ by gas chromatography-mass selective detector. To analyze ${\alpha}$-naphthylamine in urine, high performance liquid chromatography-electrochemical detector and gas chromatography-electron capture detector operating conditions have been optimized by preliminary expriment. In high performance liquid chromatography-electrochemical detector, the mobile phase was consisted of acetonitrile(35%) and water(65%), and the flow rate was maintained at 1.0ml per minute. Optimal detective condition was 9.0V(10nA/V) of electrochemical detector. The recovery of sep-pak treatment method was highly estimated as pretreatment of ${\alpha}$-naphthylamine in urine. The free amine was isolated by gas chromatography-electron capture detector after basic hydrosis, sep-pak treatment, toluene elution and HFBA(heptafluoro-butyric anhydride) derivatization of urine. The recovery of ${\alpha}$-naphthylamine in urine was $98.73{\pm}3.29%$ by gas chromatography-electron capture detector. The sensitivity was more higher than that of high performance liquid chromatography-electrochemical detector. Urinary ${\alpha}$-naphthylamine was detected in only one worker among nine workers. The level of ${\alpha}$-naphthylamine in urine was 6.42 ng/ml.

• Fire Science and Engineering
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• v.28 no.1
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• pp.26-30
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• 2014

A Compensation-type fire detector (CFD) is operated with two functions of a differential-temperature detector and as a fixed-temperature detector. The differential-temperature detector observes a rate of temperature increase, and the fixed-temperature detector measures a given fixed temperature. The differential-temperature detector does not observe the outbreak of fire in slowly increasing temperature conditions, whereas the fixed-temperature detector is not able to observe the outbreak of fire in conditions under predetermined temperature level. We developed a CFD to compensate for weaknesses of both detectors. To compensate for the disadvantages, a sensor of the sensor metal-insulator-transition critical-temperature sensor was used. Temperature coefficient of resistance is the sensitivity for sensor. At $55^{\circ}C$, temperature coefficient of resistance of metal-insulator-transition critical-temperature sensor was 14.15%. Temperature coefficient of resistance of thermistor was about 0.5%. This CFD was operated as two ways that fixed-temperature detector and differential-temperature detector in one sensor.

• Fire Science and Engineering
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• v.34 no.4
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• pp.29-35
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• 2020

This study was conducted to examine the performance in the space for a single alarm type detector installed in a single house. Three types of houses were used, including two types of one-story and two-story houses. A computer simulation program was used to predict the sound pressure level in response to the occurrence of an alarm sound in a residential space. The characteristics of the sound source applied to the simulation were directly measured and used as input data. As a result of simulation, it was found that the sound pressure level in the kitchen and living room generally met the standard when the alarm sound of the detector occurred. However, the sound pressure level in the bedroom was predicted to be at least 20 dB (A) lower than the American Fire Protection Association standard of 75 dB (A). Therefore, a plan should be prepared to maintain a sufficient sound level in the bedroom space inside the house, and efforts will be needed to ensure safe evacuation in case of fire by establishing relevant standards.

• Journal of KIISE:Software and Applications
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• v.31 no.6
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• pp.792-798
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• 2004

In this paper, we will introduce a new corner detector for the wafer die position recognition. The die position recognition procedure is necessary for WSCSP(Wafer Scale Chip Scale Packaging) technology, decide the accuracy of post-procedure. We present a hierarchical gray level corner detection method for the recognition of the die position from a wafer image. The new corner detector divides the corner region into many homocentric circles, and calculates the comer response and the angle of direction about each circle to get an accurate toner point. The new corner detector has a hierarchical structure so it can detect comer point more quickly than general gray level corner detector.

• Nuclear Engineering and Technology
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• v.21 no.4
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• pp.294-301
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• 1989

The Axial Power Distribution Monitoring System(APDMS) program was developed to calculate a detailed axial power distribution using two-level excore detector, cold leg temperature and control rod position signals. The unnormalized two-level excore detector signals were corrected for the rod shadowing factor determined by control rod position and for the temperature shadowing factor calculated based on cold leg temperature. A shape annealing matrix was then applied to the corrected excore detector response to yield peripheral power. After the core average power was obtained using linear relationship bet-ween core average and peripheral power, the boundary point power correction coefficient was applied to core average power in order to obtain boundary power for both upper and lower core axial boundaries. Then, the axial power distribution was synthesized by spline approximation. In spite of burnup, power level, control rod postion and axial offset changes, the comparisons of axial power distributions between BOXER simulation program and APDMS results showed good agreements within 5% root mean square error for Kori Unit 3 Cycle 4.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.159-165
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• 2005

The characterization of radiological contamination inside pipes generated during the decommission of a nuclear facility is necessary before pipes can be recycled or disposed. But, existing direct measurements of radioactive contamination level using the survey-meter can not estimate the characteristic of contamination on a local area such as the pipe inside. Moreover, the measurement of surface contamination level using the indirect methods has many problems of an application because of the difficulty of collecting sample and contamination possibility of a worker when collecting sample. In this work, plastic scintillator was simulated by using Monte Carlo simulation method for detection of beta radiation emitted from internal surfaces of small diameter pipe. Simulation results predicted the optimum thickness and geometry of plastic scintillator at which energy absorption for beta radiation was maximized. In addition, the problem of scintillator processing and transferring the detector into the pipe inside was considered when fabricating the plastic detector on the basis of simulation results. The characteristic of detector fabricated was also estimated. As a result, it was confirmed that detector capability was suitable for the measurement of contamination level. Also, the development of a detector for estimating the radiological characteristic of contamination on a local area such as the pipe inside was proven to be feasible.

• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.231-236
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• 2004

An imaging plate(IP) detector, a two-dimensional digital radiation detector that can acquire image of radioactivity distribution in a sample, has been applied in many fields; for industrial radiography, medical diagnosis, X-ray diffraction test, etc. In this study, the possibility of IP detector to be used lot measuring radioactivity of sample is explored using its high sensitivity, higher spatial resolution, wider dynamic range and screen uniformity for several kinds radiations. First, the IP detector is applied to measure the surface uniformity for area source. Surface uniformity is measured rapidly and nondestructively by measuring the radioactivity distribution of common standard area source$(^{241}Am)$. Next, the IP is employed to study the possibility of measuring an extremely low-level activity of environmental sample. For this study the screen uniformity, shield effect of background radiation, linear dynamic range and fading effect of the IP detector is investigated. The potato, banana, radish and carrot samples are chosen to measure ultra low-level activity of $^{40}K$ isotope. The efficiency calibration of IP detector is carried out using the standard source.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.89-94
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• 2013

The fire testing performed for smoke detector model approval in Korea tests only one kind of fire smoke. A photoelectric spot-type smoke detector using Mie scattering is affected by the wavelength of light beam and the particle diameter. According to UL (Underwriters Laboratories Inc.) 268 standard, this paper analyze the characteristic of the response for a photoelectric spot-type smoke detector on sale in Korea using various fire smokes. Probability that the response time is included in non-defective range is 100% in paper fire, 90% in wood fire and 75% in flammable liquid fire, 90% in wood fire and 75% in flammable liquid fire. According to the estimation for population mean of the response time choosing a confidence level of 99%, a maximum of 19% for wood fire and that of 38% for flammable liquid fire are defective. As the result of analysis of smoke particle, this paper is found that these results are caused by the smoke particles are wide variations in size or have very black.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.421-424
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• 2017

This paper describes a full-wave rectifiers for energy harvesting circuit using vibration detector. The designed circuit operates only when the vibration is detected through the vibration detector and the active diode. When there is no vibration, the comparator is turned off to prevent leakage of energy stored in the $C_{STO}$. The energy stored in the capacitor is used to drive the level converter and the active diode. The energy stored in the capacitor is supplied to an active diode designed as an output power. The vibration detector is implemented with Schmitt Trigger and Peak Detector with Hysteresis function. The proposed circuit is designed in a CMOS 0.35um technology and its functionality has been verified through extensive simulations. The designed chip occupies $590{\mu}m{\times}583{\mu}m$.