• Journal of Korean Society for Quality Management
• /
• v.38 no.4
• /
• pp.504-511
• /
• 2010

A fuze detonator comprising star shells is an important device so that its failure usually leads to failure of the shells. In this paper, accelerated degradation tests of RD1333 (lead azide) using temperature stress were performed, and then degradation data of explosive power for the detonator were analyzed to predict the storage lifetime of detonator. Degradation data analysis to estimate the storage lifetime is based on a distribution-based degradation process. Statistical distribution parameters of explosive power degradation measures at each time were estimated for each temperature level, and then reliability of the detonator for each accelerated temperature level was estimated using both time-varying distribution parameters and critical level of explosive power. Arrhenius model was applied to estimate storage lifetime of the detonator under the field temperature condition. Accelerated distribution-based degradation analysis to estimate storage lifetime is explained in detail, and estimation results are compared to field data of storage lifetime in this paper.

• Proceedings of the Korean Reliability Society Conference
• /
• 2004.07a
• /
• pp.303-311
• /
• 2004

This paper presents the reliability estimation of door hinge for home appliances, which consists of bushing and shaft. The predominant failure mechanism of bushing made of polyoxymethylene(POM) is brittle fracture due to decrease of strength caused by voids existing, and that of shaft made of acrylonitrile-butadiene-styrene(ABS) is creep due to plastic deformation caused by excessive temperature and lowering of glass transition temperature by absorbed moisture. Since the brittle fracture of bushing is overstress failure mechanism, the load-strength interference model is used to estimate the failure rate of it along with failure analysis. By the way, the creep of shaft is wearout failure mechanism, and an accelerated life test is then planned and implemented to estimate its lifetime. Through the technical review about failure mechanism, temperature and humidity are selected as accelerating variables. Assuming Weibull lifetime distribution and Eyring model, the life-stress relationship and acceleration factor, B$_{10}$ life and its lower bound with 90% confidence at worst case use condition are estimated by analyzing the accelerated life test data.a.

• Korean Journal of Bronchoesophagology
• /
• v.6 no.2
• /
• pp.152-158
• /
• 2000

Backgroud and Objectives： Because the pain is subjective in human, we frequently need the objective tool for estimation of pain. The Visual Analog Scale (VAS) is a method for pain grading, but it is also a subjective method. The purpose of this study is to seek an objective method for measurement of pain. Author suggests that the estimation of local body temperature may be associated with the severity of pain in tonsillar disease and the change of it measured by Digital Infrared Thermographic Imaging (DITI), may also be correlated with the change of pain. Materials and Method : Four groups were selected and measured for VAS and body temperature in DITI. Group A and B were post-tonsillectomy groups divided by age. Group C was acute tonsillitis group. Group D was peritonsillar abscess group. Results : In Group A and B, the subjective VAS was significantly correlated with objective local body temperature (correlation coefficient r=0.673, 0.647) and significant correlation was also present in acute tonsillitis and peritonsillar abscess groups(r=0.596,0.642). Conclusion : The change of pain was strongly associated with that of local body temperature in tonsillar disease. DITI is a useful method for objective grading of pain and can be used for the study of postoperatve pain and effectiveness of pain control.

• Korean Journal of Food Science and Technology
• /
• v.22 no.5
• /
• pp.582-589
• /
• 1990

A method for application of the equivalent time and temperature point for estimating kinetic parameters was proposed. The feasibility of the method was demonstrated with both theoretical and empirical kinetic data. The theoretical kinetic data were obtained from the arbitrarily chosen time-temperature data for three chemical reactions whose kinetics are well established. The experimental kinetic data were obtained for the acid (0.0005 N HCl) catalyzed hydrolysis of sucrose(2%). The activation energy and the frequency factor determined by the proposed method were $104.74{\pm}1.87kJ/mol\;and\;5.62{\times}10^{14}\;hr^{-1}$ respectively and the results agreed well with those obtained by a different method of kinetic parameter estimation, i.e. the linearly increasing temperature method.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.440-445
• /
• 2008

In this paper, new methodology is proposed to estimate the cooling load using areas of building group and predicted weather data. Only three parameters such as maximum, minimum temperature and building area are necessary to obtain hourly distribution of cooling load for the next day. The maximum and minimum temperature that are used for input parameters can be obtained from forecasted weather data. The areas of building group are used for setting several parameters that are used for estimate cooling loads. Benchmarking building(research building) is selected to validate the performance of the proposed method, and the estimated cooling loads in hourly bases are calculated and compared with the measured data for benchmarking building. The estimated results show fairly good agreement with the measured data for benchmarking building.

• Environmental and Resource Economics Review
• /
• v.27 no.2
• /
• pp.287-313
• /
• 2018

This paper measures and analyzes cooling and heating demand in Korean electricity demand using time-varying temperature response functions and cooling and heating temperature effects. We fit the model to Korean data for residential and commercial sector over 1999:01~2016:12 and the estimation results show that the growth rate of heating demand is much higher than that of base and cooling demand, and especially the growth rate of heating demand in commercial sector is much higher. And we define the temperature-normalized demand conditioning that monthly temperatures are assumed as average monthly temperatures. The growth rate of heating demand in the estimated temperature-normalized demand is higher than that in the real demand. Our results are expected to be a base data for Winter Demand Management and short-term electricity demand forecasting.

• Journal of Climate Change Research
• /
• v.6 no.2
• /
• pp.95-104
• /
• 2015

To discuss whether we have credible estimations about historical surface temperature evolution since industrial revolution or not, present study investigates consistencies and differences of averaged surface air temperature since 1900 between the multiple data sources: Hadley Center Climate Research Unit (HadCRU4) surface air temperature data, ECMWF 20 Century Reanalysis data (ERA20CR), and NCEP 20 Century Reanalysis data (NCEP20CR). Averaged surface temperatures are obtained for the global, polar (90S~60S, 60N~0N), midlatitude (60S~30S, 30N~60N), tropical (30S~30N) region, separately. From the analysis, we show that: 1) spatio-temporal inhomogenity and scarcity of HadCRU4 data are not major obstacles in the reliable estimation of global surface air temperature. 2) Globally averaged temperature variability is largely contributed by those of tropical and midlatitude, which occupy more than 70% of earth surface in area. 3) Both data show consistent temperature variability in tropical region. 4) ERA20CR does not capture warm period over Arctic region in early 1900s, which is obvious feature in HadCRU4 data. Discrepancies among datasets suggest that high-level caution is needed especially in the interpretation of large Arctic warming in the early 1900s, which is often regarded as a natural variability in the Arctic region.

• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.5
• /
• pp.359-364
• /
• 2013

This study was conducted to develop a model to estimate crop leaf surface temperature. The results were as following; A definition for the daily time based on elapsed time from the midnight (00:00) as "E&E time" with the unit of Kmin. was suggested. The model to estimate the scaled temperature ($T^*e$) of crop leaf surface temperature by scale factor ($T^*$) according to the "E&E time : Kmin."(X) was developed as eq. (1) $T^*e=0.5{\cdot}sin(X+780)+0.5$ (2) $T^*=(Tx-Tn)/(Tm-Tn)$, Tx : Daily leaf temperature, Tm : Daily maximum leaf temperature, Tn : Daily minimum leaf temperature. Relative sensitivity of the measured temperature compared to the estimated temperature of red pepper, soybean and persimmon was 1.078, 1.033 and 0.973, respectively.

• Journal of Navigation and Port Research
• /
• v.35 no.5
• /
• pp.401-406
• /
• 2011

In the near future, the marine resort development will increase because people's requirements of marine leisure are raising. Instead of marine resort development by reclamation which causes environmental disruption, it is expected that marine resort development using floating structures increases. And the requirement of floating hotel that is main facilities of marine resort grows too. It is necessary to investigate the load estimation of floating hotel. The floating hotel has two characteristics, both hotel and ship. Accordingly, this study examines the consideration points for planning the load estimation of floating hotel, and the results of load estimation of ship and hote are investigated.

• Journal of Korean Society of Rural Planning
• /
• v.23 no.4
• /
• pp.153-168
• /
• 2017

The main objective of this study was to assess reference evapotranspiration based on multiple GCMs (General Circulation Models) and estimation methods. In this study, 10 GCMs based on the RCP (Representative Concentration Pathway) 4.5 scenario were used to estimate reference evapotranspiration. 54 ASOS (Automated Synoptic Observing System) data were constructed by statistical downscaling techniques. The meteorological variables of precipitation, maximum temperature and minimum temperature, relative humidity, wind speed, and solar radiation were produced using GCMs. For the past and future periods, we estimated reference evapotranspiration by GCMs and analyzed the statistical characteristics and analyzed its uncertainty. Five methods (BC: Blaney-Criddle, HS: Hargreaves-Samani, MK: Makkink, MS: Matt-Shuttleworth, and PM: Penman-Monteith) were selected to analyze the uncertainty by reference evapotranspiration estimation methods. We compared the uncertainty of reference evapotranspiration method by the variable expansion and analyzed which variables greatly influence reference evapotranspiration estimation. The posterior probabilities of five methods were estimated as BC: 0.1792, HS: 0.1775, MK: 0.2361, MS: 0.2054, and PM: 0.2018. The posterior probability indicated how well reference evapotranspiration estimated with 10 GCMs for five methods reflected the estimated reference evapotranspiration using the observed data. Through this study, we analyzed the overall characteristics of reference evapotranspiration according to GCMs and reference evapotranspiration estimation methods The results of this study might be used as a basic data for preparing the standard method of reference evapotranspiration to derive the water management method under climate change.