• The Journal of Information Technology
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• v.5 no.4
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• pp.57-64
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• 2002

The system that is thermal test system for elements has been controlled generally by PID algorithm because of its characteristic. There is not a mathematical model for the system. So the system that is use the PID controller is not properly operated. To solve this problem, we propose a fuzzy algorithm that parameters and rule base is selected by self-searched algorithm for each system. The input fuzzy membership function is adapted based on the set stable range. Output membership function is nearly fixed but some parameter is adjustable. The rule base is changed under basis on the system response. The output value computed through inference and defuzzification is mapped into a value that is proper for the system operation. Through this regulation, it will be possible to prevent the temperature of system to go into the unstable temperature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.129-132
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• 2010

The objective of IM rocket motor is to minimize the probability of inadvertent initiation and severity of subsequent collateral damage, hence it is important to define personnel and equipment survivability to a rocket motor accident. The violent response probability associated with shock, impact and thermal effects be minimized. And during production, transportation/storage and stack of rocket motor, sympathetic detonation, giving severe effects of the propagation of adverse reaction on its surroundings, be reduced. Hence Reaction type also based on reaction results of the overpressure, fragment throw and heat flux.

• Steel and Composite Structures
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• v.12 no.4
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• pp.325-350
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• 2012

Concrete filled steel hollow structural sections (CFSs) are an efficient, sustainable, and attractive option for both ambient temperature and fire resistance design of columns in multi-storey buildings and are becoming increasingly common in modern construction practice around the world. Whilst the design of these sections at ambient temperatures is reasonably well understood, and models to predict the strength and failure modes of these elements at ambient temperatures correlate well with observations from tests, this appears not to be true in the case of fire resistant design. This paper reviews available data from furnace tests on CFS columns and assesses the statistical confidence in available fire resistance design models/approaches used in North America and Europe. This is done using a meta-analysis comparing the available experimental data from large-scale standard fire tests performed around the world against fire resistance predictions from design codes. It is shown that available design approaches carry a very large uncertainty of prediction, suggesting that they fail to properly account for fundamental aspects of the underlying thermal response and/or structural mechanics during fire. Current North American fire resistance design approaches for CFS columns are shown to be considerably less conservative, on average, than those used in Europe.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.2
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• pp.90-95
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• 2009

All-optical fiber-type gain flattening filer (GFF) for an EDFA (Erbium doped fiber amplifier) were fabricated by using a FBT (fiber biconical tapered) process and the performance of the GFF was tested and athermal package was proposed. Historically, the chief contributor to gain unevenness has been the EDFA. Due to the inherent gain response of the EDFA's operation, there is always a modest imbalance in the gain applied as a function of wavelength. FBT methods have been used to make fiber type couplers and WDM filter since 1980. Attractivity of this methods was simple, cost effective and thermal stability. Simulation program tool is made to design target GFF profile for this paper. Fiber coupler manufacturing machine is modified for the GFF process. The final GFF is obtained by cascading 4 unit filter that has 6 taper stage. Test result shows 1 dB of wavelength flatness in the C band. Polarization dependent loss is under 0.15dB. The center wavelength variation is below ${\pm}$0.35nm at the temperature range of $20^{\circ}C$ to $70^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.55 no.5
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• pp.284-291
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• 2022

Herein, we studied ultrathin Cu-layer-based transparent heaters embedded between a ZnO underlayer and an Al₂O₃ overlayer. The anti-reflecting functions for the ZnO and Al₂O₃ layers by independently varying the layer thicknesses, with the Cu layer thickness fixed at 8.5 nm. The smallest visible light transmittance of 11.1% was achieved when the overlayer and underlayer thicknesses were 90 and 30 nm, respectively. We conducted electrically driven Joule heating test for the Cu layers having thicknesses of 8.5 nm (R_s: 14.7 Ohm/sq.) and 19 nm (R_s: 3.4 Ohm/sq.). External voltages were increased with an interval of 2 V until irreversible failures occurred at temperatures of ~390 ℃ and 550 ℃, respectively. At each voltage increase before heater failures, the heater exhibited superior thermal response with the heater temperatures reaching over 90% of the final temperatures. The heaters also showed excellent reproducibility when turning on and off the heater repeatedly.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1448-1459
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• 2023

A key element of the safety analysis is Loss of Coolant Analysis (LOCA) which must be performed using system thermal-hydraulic codes. These codes are extensively validated against separate effect and integral experiments. RELAP/SCDAPSIM is one such code that may be used to predict LBLOCA response in a CANDU reactor. The RD-14M experiment selected for the Best Estimate Plus Uncertainty study is a 44 mm (22.7%) inlet header break test with no Emergency Coolant Injection. This work has two objectives first is to simulate pipe break with RELAP and compare these results to those available from experiment and from comparable TRACE calculations. The second objective is to quantify uncertainty in the fuel element sheath (FES) temperature arising from model coefficient as well as input parameter uncertainties using Integrated Uncertainty Analysis package. RELAP calculated results are found to be in good agreement with those of TRACE and with those of experiments. The base case maximum FES temperature is 335.5 ℃ while that of 95% confidence 95^th percentile is 407.41 ℃ for the first order Wilk's formula. The experimental measurements fall within the predicted band and the trends and sensitivities are similar to those reported for the TRACE code.

• Fire Science and Engineering
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• v.23 no.5
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• pp.57-65
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• 2009

This study was intended to conduct a Real-scale fire test to predict the fire behavior by unit space at the apartment building where a huge casualties and injuries are likely. After setting the inflammables inside the house, the test aimed to identify the fire characteristics to each unit item was carried out. The house was divided into 4 unit space such as kitchen, living room, bedroom and a study for a real scale fire test. As a result, bedroom reached to flashover state in 5minutes after setting the fire, indicating a rapid fire growth such as 7433.3kW of maximum thermal emissivity, 578.6ppm of carbon monoxide, 1.25ppm of carbon dioxide and $1,350^{\circ}C$ of maximum indoor temperature. Particularly, the fire growth was made up to critical temperature which might cause a severe damage to the people within 3minutes, if the fire were not extinguished at inflammable space at the early stage of fire, which stressed the need of early response. The result of a real scale fire test could be compared with the outcome of expanded simulation test and used in predicting the fire spread at the space for different use.

• Korean Journal of Human Ecology
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• v.10 no.1
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• pp.101-111
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• 2001

The purpose of this study was to investigate using and evaluative criteria for purchasing of sleepwear in winter. Subjects were 523 males and females aged from twenties to fifties, living in Chongju and Taejon. For data analysis, frequency, descriptive analysis, t-test, and F-test were used. The results are as follows. First, the ownership of sleepwear was sweat suits with zippered top, pajamas, T-shirts/pants, underwear, and nightgown in order. The mean of using sweat suits was used the highest, and subjects used more home wear than sleepwear in winter. Second, the using or sleepwear had a significant difference in cold-sensitiveness and body types. Cold-sensitive group used sweat suit and T-shirts/pants more than cold-insensitive group. Also, groups who are thin wore sweat suit the most while groups who are corpulent, used underwear the most when they slept. Third, subjects, who are married women and use bed, used nightgown, but pajamas were used by groups who are older, married, and professional. Sweat suits and T-shirts/pants were used the most by single aged twenties. Forth, consumers considered the wearing comfort when they purchased sleepwear for winter, and they evaluated washing/management, fabric, design/style, economic, service, brand, and others' response in order, for judging the quality of sleepwear. Also, the evaluative criteria had a significant difference in demographic variables such as sex, occupation, and marital state. These results implied that sleepwear would be needed for winter in terms of behavioral temperature regulation. Especially, cold-sensitive and thin group would wear knitted and two-piece sleepwear for thermal comfort when they sleep in winter. Also, Using and evaluative criteria of sleepwear would be different in demographic characteristics. For winter, sleepwear should be develop based on physiologic as well as demographic variables.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.343-359
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• 2016

Objective:In this study, we designed working clothes for livestock farmers to wear in spring and autumn to improve their work efficiency, conducted a physiological test on their performance, and evaluated their comfort. Background: In recent years, livestock farming in Korea has expanded, yet farmers' safety and sanitation levels remain low in hazardous environments that include organic dust, toxic gas, and heat stress, as well as the risk of accidents. Furthermore, most livestock farmers wear ordinary or dust-resistant clothes that are unsuitable for rearing livestock and compromise their safety and health. Thus, it is important to design specialized working clothes for livestock farmers that are comfortable and that minimize their health and safety risks. Method: To this end, we examined the literature on livestock (poultry, swine, and cattle) farmers' safety and sanitation issues, designed appropriate working clothes, and tested them in terms of sensory feel, physiological response, and subjective comfort. Results: The respondents expressed satisfaction with the new working clothes. The results of a physiological test showed a decline in temperature and humidity inside the clothes, a lower pulse rate, and a lower oxygen intake compared to the measurements taken when famers wore their previous working clothes. This indicates a fall in heat stress and fatigue, which was mostly consistent with the results of the assessment of subjective comfort. Conclusion: The results of the analysis show an improvement in the comfort of the new working clothes compared to the dust-resistant clothes that are widely worn. Based on this study, the new working clothes need to be further tested and evaluated to improve the design. Application: This study is expected to contribute to designing better working clothes for livestock farmers.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.1
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• pp.21-25
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• 2004

People in tropics have the ability to tolerate heat by residential permanence in the tropics. Previously, we have shown that African and Thai subjects who lived for whole their lives in only their respective countries sweat less under hot conditions than South Koreans who also lived whole their lives in Korea. The difference in sweating responses was attributed to the dissimilar central and peripheral sweating mechanisms operating in people from both groups. In the present study, acetylcholine (ACh), the primary transmitter for the sudomotor functions, was iontophoretically administered to South Koreans and Africans to determine the characteristic sudorific responses of their acclimatized biologic make-up to their respective environments. Using quantitative sudomotor axon reflex test (QSART), direct (DIR) and axon reflex (AXR) responses were evaluated. The findings revealed that the sweat onset-time among South Koreans was 0.91 min earlier than among Africans (P<0.01). The axon reflex sweat volume of nicotine receptor activity AXR(1) and sweat volume of muscarinic receptor activity DIR(2) among South Koreans were 79% and 53% greater (P<0.01), respectively. These results indicate that the reduced thermal sweating among Africans is at least in part attributed to the diminished sensitivity of sweat glands to ACh.