• Fire Science and Engineering
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• v.28 no.6
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• pp.62-68
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• 2014

The high predictive performance of fire detector models is essentially required for the reliable design of evacuation safety using the fire modeling. The main objective of the present study is to measure input information in order to predict the accurate activation time of photoelectric smoke detector adopted in fire dynamics simulator (FDS) recognized a representative fire model. To end this, the fire detector evaluator (FDE) which could be measured the device properties of detector was used, and the input information of Heskestad and Cleary's models was obtained for a spot-type photoelectric smoke detector. In addition, the activation times of smoke detector predicted using default values into FDS and measured values in the present study were quantitatively compared. As a result, the Heskestad model could result in an inaccurate the activation time of photoelectric smoke detector compared to the Cleary model. In addition, there was a distinct difference between the default values used into FDS and the measured values in terms of device properties of smoke detector, and thus the activation time also showed a significant difference.

• Fire Science and Engineering
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• v.31 no.6
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• pp.8-15
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• 2017

Most fire victims succumb to smoke inhalation, and fire smoke toxicity from interior materials is increasing with increased use of plastics. Large amounts of hazardous effects of smoke are related to deposition of smoke particles in respiratory tracts, and deposition characteristics are influenced by size distribution of particles. Thus, it is essential to know the size distribution of smoke particles from plastics for hazard analysis of fire smoke. In a recent study, it has been shown that size distributions of smoke particles from PP are different from wood in many aspects. In order to know whether other plastics show the same characteristics as PP, size distributions of smoke particles from four plastic materials (LDPE, PA66, PMMA, and PVC) were measured in real time under each fire type with various temperature and oxygen supply. In this study, smoke particles from different plastics were generated uniformly by using steady-state tube furnace method provided in ISO/TS 19700. Their size distributions were measured by using an electrical low pressure impactor (ELPI). Results of measurements showed that size distributions of smoke particles from these four plastic materials were similar to those from PP in many aspects. However, they were distinctively different from those of wood.

• Korean Security Journal
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• no.23
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• pp.41-63
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• 2010

This study aimed to asses the relationship between shoppers' security need sufficiency and customer satisfaction on the quality of security services in Shopping Mall. This study gathered data from 485 citizen in five shopping centres at KyungKi areas. Collected data was analysed by factor analysis, reliability analysis, path analysis and multiple regression analysis with SPSS WIN 16.0. The results of the study yielded the following four perspectives. First, secure equipment and the service quality of security officers in the shopping malls have a decisive effect on customers psychological stability and crime prevention. Second, they are a strong influence upon customer satisfaction and operational security. Especially, the professionalism of the staff has a marked effect. Third, the service quality of security officers and secure equipment in the malls have an effect on operational security services and efficiency of secure services. Finally, this dissertation showed that the quality of secure equipment services and officers' mild In summary, the conclusion of this study is that secure equipment service, officers' mild manner and professionalism of the security officers affect the customer satisfaction measurement directly. They also affect customer satisfaction through psychological stability and the prevention of crime indirectly. In other words, the good quality of security in the shopping centres affects the using of facilities definitely.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.521-529
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• 2016

Since Gamma Knife(R) radiosurgery(GKRS) is based on a single-fraction high dose treatment strategy, independent verification for the results of Leksell GammaPlan(R) (LGP) is an important procedure in assuring patient safety and minimizing the risk of treatment errors. Several verification methods have been developed and reported previously. Thus these methods were tested statistically and tried on Leksell Gamma Knife(LGK) target treatments through the embodiment of the previously proposed algorithms(PPA). The purpose of this study was to apply and evaluate the accuracy of verification methods for LGK target treatments using PPA. In the study 10 patients with intracranial lesion treated by GKRS were included. We compared the data from PPA and LGP in terms of maximum dose, arbitrary point dose, and treatment time at the isocenter locations. All data were analyzed by Paired t-test, which is statistical method used to compare two different measurement techniques. No statistical significance in maximal dose at 10 cases was observed between PPA and LGP. Differences in average maximal dose ranged from -0.53 Gy to 3.71 Gy. The arbitrary point dose calculated by PPA and LGP was not statistically significant too. But we found out the statistical difference with p=0.021 between TMR and LGP for treatment time at the isocenter locations. PPA can be incorporated as part of a routine quality assurance(QA) procedure to minimize the chance of a wrong overdose. Statistical analyses demonstrated that PPA was in excellent agreement with LGP when considering the maximal dose and the arbitrary point dose for the best plan of GKRS. Due to the easy applicability we hope PPA can be widely used.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.126-133
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• 2014

The main source of bridge destruction is due to scour. The bridge scour is the result of erosive action of flowing water taking away ground materials from near the abutment or pier. Furthermore, the water level must be also monitored whiling flooding, because it dangers not only the stability of bridge itself, but the safety of bridge users. This study is intended to develop a new measuring system for bridge scour by overcoming the current limitation of scour measurement technique. This measuring system is confirmed its excellence and validity through this study. The newly developed measuring system finds the distance between the water surface and the ground surface by detecting temperature difference along the abutment vertically. The measuring mechanism for monitoring the bridge scour and water level is based on identifying the temperature difference among mediums, including air, water and ground. In order to validate the new measuring system, the lab experiments and the field tests are conducted and compared. It has been confirmed that this system can effectively measure the bridge scour and the water level by analyzing the temperature distribution between mediums and the temperature variation over time.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.3
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• pp.242-248
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• 2015

Maximum mouth opening is regarded as an important tool used to evaluate the clinical function of temporomandibular joint and the masticatory system. It has been reported that children can also exhibit severe dysfunction or pain in some cases of temporomandibular disorder. The purpose of this study was to measure the normal maximum mouth opening in Korean children and to analyze the correlations between mouth opening and the associated factors. Maximum mouth opening was measured from 151 healthy children between the ages of 2 and 6 years old. Age, height, weight, and mouth width were also recorded. As a result, the mean maximum mouth-opening was $37.72{\pm}5.10mm$. While the values were greater in boys than in girls without statistical significance, the increases of maximum mouth opening based on age, height, weight, and mouth width were significant (p < 0.05). In children, positive correlation coefficients were observed between maximum mouth opening and the associated factors and height showed the highest correlation. In conclusion, we collected data of the normal range of maximum mouth opening in Korean children, and this study can be utilized as a basis in diagnosing pediatric temporomandibular disorder and safety standard of mouth opening during dental procedures.

• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.263-268
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• 2004

Using the Monte Carlo simulation, a study on the lion-proportionality of the prototype phoswich detector with $2'{\times}2'$ CSI(Tl) and plastic scintillator, which was made by KAERI, has been carried. The defector response functions (DRFs) calculated by simulations were compared with the experimental measurement on the $^{137}Cs\;and\;^{60}Co$. To precisely simulate the DRF for the phoswich, the CSI(Tl) non-proportionality was calculated using the electron response and the simplified electron cascade sequence for treating the photoelectric absorption event. The resulting DRFs of $^{137}Cs\;and\;^{60}Co$ sources obtained by simulations were compared with experiments for verification. For $^{137}Cs$, gamma-ray responses simulated by MCNP5 are generally good agreement with the measured ones. But the DRF of $^{60}Co$ does not match well with the results of experiment in the energy region below second peak due to the coincidence effect of two gamma-rays (1.17 MeV and 1.33 MeV). Through the analysis of the non-proportionality of CsI(Tl) in the prototype phoswich, the improved DRFs considering non-proportionality were produced and the simulation results were verified using the experimental measurements. However, to more precisely reproduce the DRF for the phoswich, further studies in relation to the electron channeling effect and the Doppler broadening effect of a scintillator are still needed as well as considering that effect of the transfer contribution.

• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.426-435
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• 2010

The object of this study was to develop an index of service quality of waterparks and verify the validity and reliability of the index. This study represents the waterparks user population in 2009, and 250 people were extracted by using the purposive sampling method. In other words, five locations have major waterparks were chosen and 50 people per each location were collected. Conference, panel survey, exploratory factor analysis and confirmatory factor analysis were performed to verify the validity of the questionnaire while item analysis, interrater reliability and internal consistency reliability were conducted to probate the reliability. Through these methods and procedures, the results of this study like these; (i) Validity of this index was significantly high and the index include amenity/cleanness, safety, price, programs, facilities, accessibility and promotion. Among them, amenity/cleanness was the major factor for the validity value; (ii) Reliability of this index was also high. There are high correlations between questions and fields and questions and total score. And the Cronbach's $\alpha$ values of the internal consistency reliability was over 0.603 except in the case of promotion which was below 0.6. After all the analysis, the index of service quality proved to be very proper and reliable index. Therefore, the major factors of service quality have to be figured out and reflected to the management innovation to improve service quality of waterparks.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.357-365
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• 2011

Exposure measurement of agricultural worker to pesticide is one of important part of health risk assessment of pesticide. Therefore exposure matrices, apparatus, instruments and methods must be validated in advance to field experiment. In this study, method validation with an organophosphorus insecticide fenthion was carried out for exposure monitoring of agricultural worker. LOD and LOQ were 0.01 and 0.05 ng, respectively. Calibration curve linearity ($R^2$ > 0.999) and reproducibility (C.V. < 3%) were also excellent. Recovery at LOQ, 10LOQ and 100LOQ levels from gloves, socks, mask, patch, solid sorbent, glass fiber filter was 76~113% (C.V. < 3%). Trapping efficiency was 95~105% while no breakthrough was observed. Method validation for the exposure monitoring was established successfully through several experiments. Such method validation can be usually performed in laboratory and not much different for each pesticide so that, this techniques will be applied widely in research for pesticide exposure monitoring by combination with body surface area and respiration rates.

• Journal of Distribution Science
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• v.16 no.8
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• pp.79-89
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• 2018

Purpose - This research aims to investigate the factors that influence consumer's overseas online shopping behavior. Consumers adopt overseas online shopping as a new buying way and more and more consumers prefer overseas online shopping than traditional shopping ways. Consumers' behaviors in this shopping experience can be different from other shopping experiences. With the increase of overseas online shopping, we need to find antecedents and results of overseas online shopping. Especially there would be positive or negative factors which influence overseas online shopping motivation. To find the relationship, this study examines self-efficacy and impulsivity as major factors which influence overseas online shopping. We also suggest that several attitude factors increase self-efficacy and it is positively related to customer satisfaction. On the other hand, we assume that overseas online shopping factors influence impulsivity of buying and it will decrease customer satisfaction. Research design, data, and methodology - This empirical study data were collected from Korean people who experience overseas online shopping. The subjects for this study were confined to shoppers who used overseas online shopping within the past six months. A total of 267 responses were gathered. SPSS 23.0, PLS 2.0 software were used in the data analysis. Descriptive statistics were used to show sample characteristics. We examined reliability, validity test for constructs. All measurement items used seven-point scales(1= very strong disagree, 7 = very strongly agree) drawn from previously published papers. Partial Least Square method was applied to find the relationship between antecedent factors and dependent factors and hypotheses were estimated. Results - Results show that perceived superiority, perceived ease of use, perceived transaction safety, perceived behavioral control positively affect self-efficacy. Self-efficacy influences positively to consumer's post purchase satisfaction. Perceived monetary benefit and perceived uniqueness motivated impulse buying. This can make consumer's post purchase dissatisfaction. Conclusions - This paper attempted to confirm the existence of both the positive and negative faces of overseas online shopping. The result reveals that self-efficacy is a major factor which may increase satisfaction in the overseas online shopping. Usually, we can think monetary benefit and uniqueness of products motivate overseas online shopping. But it can also intrigue impulse buying and negatively affect customer relationship. Therefore companies should provide enough products information to their potential customers and they might apply adequate processes such as recommendation, comparing systems to build long term relationship with their customers.