• 한국응급구조학회지
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• 제10권3호
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• pp.71-85
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• 2006

Purpose: The purpose of this study is to investigate the relationship among the variables, personality type, stress, and job satisfaction in firefighters. Methods: The questionnaire research was conducted for field service firefighters who work in two cities for the period of June 20, 2005 through July 20, 2005. A total number of 308 data were used for this analysis. For analysis of the data, the SPSSWIN 10.0 program was used to analyze descriptive statistics, correlation analysis, t-test and one-way ANOVA. Results: The mean score of subjects' stress was 3.30 and the mean score of job satisfaction was 2.86. There were significant differences on stress and job satisfaction by general characteristics. Stress was significantly differed by field of working. Job satisfaction was significantly differed by marital status and field of working. Also, there were significant differences on stress and job satisfaction by characteristics related to working. Stress was significantly differed by sleeping time at night shift, witness their superior's or companion's death or injury, and a threat to death or injury. Job satisfaction was significantly differed by an aptitude for field of working and wish to change the field of working. But there was no significant differences on stress and job satisfaction by personality type. There was statistically significant negative correlation between stress and job satisfaction. Conclusion: Strategies that can decrease their stress need to be developed to increase job satisfaction.

• 대한기계학회논문집
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• 제12권2호
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• pp.373-380
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• 1988

본 연구의 목적은 음장의 입자속도가 기류의 평균속도와 비슷한 크기인 경우에 원통으로부터 열전달의 동특성과 한 사이클의 평균값인 평균열전달이 음장에 의하여 어떠한 영향을 받는가를 구하기 위한 것이다.

• Composites Research
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• 제36권3호
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• pp.205-210
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• 2023

본 연구에서는 폼 구조의 효율적인 유효 기계적 물성 및 열전도율 예측을 위한 균질화 데이터 기반 전이학습 프레임워크를 개발하였다. Eshelby 텐서 기반의 평균장 균질화(Mean-field homogenization, MFH)는 타원체 형태의 공동을 포함하는 다공성 구조의 물성을 효율적으로 예측할 수 있지만, 셀룰러(cellular) 폼 구조의 물성은 정확하게 예측하기 어렵다. 한편, 유한요소 균질화(Finite element homogenization, FEH)는 정확성은 높지만 상대적으로 높은 해석 시간을 동반한다. 본 논문에서는 평균장 균질화와 유한요소 균질화의 장점을 결합한 데이터 기반 전이학습 프레임워크(Framework)를 제안하였다. 구체적으로, 대량의 평균장 균질화 데이터를 도출하여 사전학습 모델(Pre-trained model)을 구축하고, 상대적으로 소량의 유한요소 균질화 데이터를 이용하여 미세 조정(Fine-tuning) 하였다. 제안된 프레임워크를 검증하기 위한 수치 예제를 수행하였으며, 해석 정확도를 확인하였다. 본 연구의 결과는 다양한 폼 구조를 가진 재료의 해석에 적용할 수 있을 것으로 기대한다.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2732-2741
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• 2000

Combination of magnetic recording technology and optical recording technology such as Near Field Optical Recording is watched recently. In order to accomplish this technology, the development of an electromagnetic driven mm-sized mirror shifting laser beam in track direction have to needed. In Near Field Optical Recording System, shifting laser beam in track direction mean as fine tracking and means as coarse tracking. Therefore in Near Field Optical Recording, 2-stage actuator is composed of servo controller in reading or recording information on disc layer. In our research, through design and simulation process of driven mm-sized mirror, we arrange systematically design process of driven mm-sized mirror having good frequency transfer characteristics. Design and simulation processes included modal analysis of spring, calculation of magnetic moment according to the number of turns and geometric configuration of coil and magnetic circuit analysis meaning that calculation of magnetic flux density in air gap of magnetic circuit. After that we design and make parts of driven mm-sized mirror, assemble and evaluate our electriomagnetic driven mm-sized mirror. we compared design values with actual characteristic values and present solution scheme. Through these processes we performed manufacturing of an electromagnetic driven mm-sized mirror having good frequency-domain characteristics and high sensitivity characteristics.

• 한국주거학회논문집
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• 제18권4호
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• pp.59-67
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• 2007

The purposes of this study were to make clear the present condition of the TVOC and HCHO concentration after renovation in apartment houses. The field measurements of TVOC and HCHO concentration according to the Korea Test Method Standard for Indoor Air Quality were carried out in 4 subject apartment houses. The results are as follows; the TVOC concentration after renovation in apartment houses ranged from mean 0.35ppm to mean 5.08ppm and increased of $0.35{\sim}5.08ppm$. The TVOC concentration of 3 subjects exceeded the Indoor Air Quality Management standard for the newly-built apartment houses (0.58ppm). The HCHO concentration after renovation ranged from mean 0.13ppm to mean 0.43ppm and increased of $0.06{\sim}0.26ppm$. The HCHO concentration of 2 subjects exceeded the Standard (0.17ppm). As results of analysis on the relation of concentrated ascension and renovation elements, the amount and the types of finishing materials and adhesives affected concentrated ascension. Also, production method for installed or purchased furniture had certain effect on the TVOC and HCHO concentration ascension.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.19-27
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• 2014

Software reliability in the software development process is an important issue. Software process improvement helps in finishing with reliable software product. Infinite failure NHPP software reliability models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, proposes the reliability model with log type mean value function (Musa-Okumoto and log power model), which made out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on mean square error (MSE) and coefficient of determination($R^2$), for the sake of efficient model, was employed. Analysis of failure using real data set for the sake of proposing log type mean value function was employed. This analysis of failure data compared with log type mean value function. In order to insurance for the reliability of data, Laplace trend test was employed. In this study, the log type model is also efficient in terms of reliability because it (the coefficient of determination is 70% or more) in the field of the conventional model can be used as an alternative could be confirmed. From this paper, software developers have to consider the growth model by prior knowledge of the software to identify failure modes which can be able to help.

• 산업기술연구
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• 제22권A호
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• pp.9-17
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• 2002

This analysis is aimed to find out how the conditions of secondary air injection affects the residence time and the turbulence energy of flue gas and flow field in a small incinerator. A commercial code, PHOENICS, is used to simulate the flow field of an Incinerator. The computational grid system is constructed in a cartesian coordinate system In this numerical experiment, an independent numerical variable is the conditions of secondary air injection and dependants are the residence time of flue gas and the mean value of turbulence energy in a primary combustion chamber. The flow field and the distribution of turbulence energy are analysed to evaluate the residence time of flue gas and the turbulence energy The computational results say that the tangential injection of secondary air make the residence time much longer than the radial injection and that the radial injection of secondary make turbulence much stronger than the tangential injection.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.192-197
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• 2003

It can be said that rock mass properties are characterized not by a mean value but by values with variation due to its characteristic uncertainty. This characteristic is one of the most important parts for the design of underground structures, but yet to be fully examined. Stochastic finite element method (SFEM) has been developed in order to take the randomness of structural systems into account. Using SFEM, the response variability of structural system can be obtained and it leads probabilistic stability of structure to be analyzed. In this study, displacements response variability of circular opening with hydrostatic stress field are analyzed in terms of rock mass properties having a certain mean and a standard deviation using the SFEM. The analyzed response variability shows that the necessity of probabilistic stability analysis of underground structures using reliable mean value and standard deviation of deformation modulus.

• 한국군사과학기술학회지
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• 제9권2호
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• pp.51-59
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• 2006

The purpose of this paper is to present reliability analysis procedures for repairable systems and apply the procedures for assessing the reliabilities of two subsystems of a specific group of military equipment based on field failure data. The mean cumulative function, M(t), the average repair rate, ARR(t), and analytic test methods are used to determine whether a failure process follows a renewal or non-renewal process. For subsystem A, the failure process turns out to follow a homogeneous Poisson process, and subsequently, its mean time between failures, availability, and the necessary number of spares are estimated. For subsystem B, the corresponding M(t) plot shows an increasing trend, indicating that its failure process follows a non-renewal process. Therefore, its M(t) is modeled as a power function of t, and a preventive maintenance policy is proposed based on the annual mean repair cost.

• 한국동물위생학회지
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• 제35권2호
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• pp.91-97
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• 2012

The strategy for infectious bursal disease (IBD) control and its success rate under field conditions depends on hygiene management, IBD field pressure, level, and variation in maternally derived IBD antibodies. This study investigated the level of IBD-specific antibody by ELISA and the prevalence of IBD virus by PCR in broilers, white-semi broilers, and Korean native chickens raised in Jeongeup, Jeonbuk. IBD-specific maternally derived antibodies were measured from 698 chickens and the mean titers of maternal antibodies were $3,572{\pm}1,402$ in broilers, $1,262{\pm}762$ in white-semi broilers, and $1,932{\pm}912$ in Korean native chickens. At 2 weeks after vaccination, the geometric mean antibody titers of broiler, white-semi broiler, and Korean native chicken were $582{\pm}427$, $3255{\pm}1,080$, and $1,023{\pm}499$, respectively. According to sequence analysis of the variable virion protein 2 gene, 4 isolates were found to be very virulent IBDV, 9 isolates classical virulent, and 2 isolates intermediate plus vaccine strain.