• 한국시뮬레이션학회논문지
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• 제28권1호
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• pp.11-21
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• 2019

무기효과 산출을 위해 모델링 및 시뮬레이션 방법을 많이 사용하고 있다. 포병탄에 대한 무기효과 산출도 일부 진행되었으나, 장약의 선택에 따른 영향에 관한 연구는 부족하였다. 따라서 본 논문에서는 장약에 기반한 포병탄 EFD 산출모형을 제시하고, 장약의 선택에 따른 3차원 건물표적에 대한 무기효과의 차이를 확인하고자 한다. 우선 산출모형의 입력데이터를 수집하고, 제시한 모형을 이용하여 요망효과 달성을 위한 발사탄수를 산출하였다. 마지막으로 제시된 모형의 검증을 위해 대응표본 t-검정을 실시하였다.

• 동아시아경상학회지
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• 제10권4호
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• pp.1-18
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• 2022

Purpose - Through the analysis and research of different characteristics and related mechanisms of live commerce anchors, this paper aimed to help live commerce anchors to strengthen their characteristic advantages, beautify the live broadcast environment, improve resource allocation and enhance business performance, so as to help live commerce anchors to achieve better high-quality development. Research design, data, and methodology - This study was conducted by sample survey method on 361 live commercial anchors who have experience in using major online shopping malls for more than one year. Data analysis methods were frequency analysis, confirmatory factor analysis, reliability analysis, correlation analysis, and structural equation model analysis. Result - Hypothesis 1 through Hypothesis 5 were all supported. The results of this study suggest that professionalism and mutual entertainment of live commercial anchors have a significant impact on business performance, survival strategy, resource allocation and environment selection. The resource allocation and environment selection of live commercial anchors play a mediating role in the professionalism and mutual entertainment of live commercial anchors on business performance and survival strategy. Conclusion -The results implied that the professionalism and inter entertainment of live commercial anchors have a positive impact on business performance and survival strategy. In the new situation, live commercial anchors should further improve their professionalism and mutual entertainment, so as to achieve better development.

• Journal of Sport and Applied Science
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• 제6권2호
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• pp.19-25
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• 2022

Purpose: This study attempts to investigate causal and intervening conditions for sport participation of Korean immigrants in the United States. Research design, data, and methodology: Grounded theory approach was used to develop a conceptual framework that presents the psychosocial processes that occur in immigrants' experience of sport participation. Participants were selected purposefully for information-rich cases. Korean immigrants with current experience of having periodically participated in sports were the criterion for sample selection. Based on selection criteria, 9 Korean immigrants took part in interview. The interview discussions were taped and transcribed verbatim into a Word file. The process for data analysis included four grounded theory approaches of purposive and theoretical sampling, an open and axial coding, memo writing, and finally the development of the conceptual framework. Results: Six concepts were revealed in the causal conditions that facilitate the process of immigrants' sport participation in the states: Personal experience, significant others, personality, physical environment, psychological well-being, and social connection. Three concepts were revealed as the intervening conditions that block the process of immigrants' sport participation in the states: Conflict with cultural change of organization, Pressure at workplace, and Economic constraints. Conclusions: Conceptual model presents causal and intervening factors. Further implications were discussed.

• 대한전자공학회논문지
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• 제12권2호
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• pp.1-10
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• 1975

본 논문은 사진데이타에 쉽게 적용할수있는 한 adaptive data compression 방법을 노표시하였다. 이웃 sample data 사이의 높은 correlation때문에 발생할 부호화 복잡성을 간편한 sample difference data로 대처하였으며, 자단의 statistical nonstationarity에 적응키 위해서 여덟가지 부호(code)로 구성된 code set중에서 최적부호를 선택토록 하였다. code erst는 두가지 등장부호와 여섯가지 보완형 Shannon-Fanro 부호로 되었다. difference data의 확률분포는 Laplacian model로, entropy의 확률분포는 Gaussian model대 하였다. 부호선별 Paranleter로서 entropy와 Pr[차이값=0]=Po를 비교하였다. 콤퓨타 실험결과 이 adaptive coding 방법으로 2대 1의 데이타 감축비를 얻었다. 이 방법은 fixed coding에 비해서 데이타 감축비와 부호화효율에서 약 10%와 15%의 이득을 주었다. 또한 도는 entropy보다 휠신 편리한 부호선별 parameter인 중시에 entropy 경우와 1% 내외의 좋은 결과를 얻을수 있음이 확인되었다. This paper presents an adaptive data compression algorithm for video data. The coling complexity due to the high correlation in the given data sequence is alleviated by coding the difference data, sequence rather than the data sequence itself. The adaptation to the nonstationary statistics of the data is confined within a code set, which consists of two constant length cades and six modified Shannon·Fano codes. lt is assumed that the probability distributions of tile difference data sequence and of the data entropy are Laplacian and Gaussion, respectively. The adaptive coding performance is compared for two code selection criteria: entropy and pr[difference value=0]=po. It is shown that data compression ratio 2 : 1 is achievable with the adaptive coding. The gain by the adaptive coding over the fixed coding is shown to be about 10% in compression ratio and 15% in code efficiency. In addition, po is found to he not only a convenient criterion for code selection, but also such efficient a parameter as to perform almost like entropy.

• 대한전자공학회논문지SP
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• 제37권5호
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• pp.64-75
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• 2000

본 논문에서는 출력 장치의 색역에 대하여 균일한 분포를 갖는 색표본(color sample) 생성 방법을 제안하고, 이를 이용한 색재현 방법을 소개한다. 즉 기존의 방법인 RGB(red, green, and blue) 혹은 CMY(cyan, magenta, yellow) 등 장치 의존형 색공간에서 균일한 색표본을 선택하는 것이 아니라 장치 독립형 균등 색공간인 CIELAB공간에서 균등 색표본을 선택하는 방법을 제안한다 또한 제안된 색표본의 성능을 평가하기 위하여 회귀 모델과 신경망을 이용한 색공간 변환을 수행하였다 동일한 크기의 색표본의 경우, 제안된 색표본을 이용한 색공간 변환 방법이 신경망, 회귀 모델 모두에서 색차를 줄일 수 있었다.

• 대한수의학회지
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• 제47권2호
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• pp.139-145
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• 2007

Measurement uncertainty could play an important role in the assessment of test results in laboratories and industries. We investigated measurement uncertainties possibly included in determination of flubendazole, a benzimidazole anthelmintic, in pork by HPLC. The concentration of flubendazole was 62.69 ng/g in a sample of pork. Uncertainty was estimated in the analytical procedure of flubendazole. A model equation was made for determination of flubendazole in pork. The four uncertainty components such as weight of sample, volume of sample, calibration curve, and recovery were selected to estimate measurement uncertainties. Standard uncertainty was calculated for each component and all the standard uncertainties were combined. The combined standard uncertainty was expanded to a sample population as an expanded uncertainty. The expanded uncertainty was calculated using k value on Student's t-table and effective degrees of freedom from Welch-Satterthwaite formula. The expanded uncertainty was calculated as 3.45 with the combined standard uncertainty, 1.584 6 and the k value, 2.18. The final expression can be ($62.69{\pm}3.45$) ng/g (confidence level 95%, k = 2.18). The uncertainty value might be estimated differently depending on the selection of the uncertainty components. It is difficult to estimate all the uncertainty factors. Therefore, it is better to take several big effecting components instead of many small effecting components.

• 천문학회보
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• 제35권2호
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• pp.31.2-31.2
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• 2010

We have performed a spectroscopic study of globular cluster (GC) system associated with the Virgo cD galaxy M87 using the Subaru/FOCAS MOS mode. We derive ages, metallicities and abundance ratios from the GC spectra using Simple Stellar Population (SSP) models. The metallicity distribution function (MDF) obtained empirically based on Milky Way GCs is consistent with the MDF derived from SSP models. A comparison with a meta-analysis using literature data sample of 15 other GC systems shows good agreement with our results. The properties of GCs acquired from the spectra will be used to test the recent theoretical prediction of a significant inflection along the colour-metallicity relations (Yoon et al. 2006). If confirmed, the non-linearity of the relations would shed new light on the interpretation of the GC colour bimodality. The robustness of our results is being tested against the choice of a SSP model, measurement errors and sample selection towards the goal of better understanding the formation history of GCs and host galaxy.

• International Journal of Reliability and Applications
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• 제13권1호
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• pp.19-35
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• 2012

This paper presents an optimum design of step-stress partially accelerated life test (PALT) plan which allows the test condition to be changed from use to accelerated condition on the occurrence of fixed number of failures. Various life distribution models such as exponential, Weibull, log-logistic, Burr type-Xii, etc have been used in the literature to analyze the PALT data. The need of different life distribution models is necessitated as in the presence of a limited source of data as typically occurs with modern devices having high reliability, the use of correct life distribution model helps in preventing the choice of unnecessary and expensive planned replacements. Truncated distributions arise when sample selection is not possible in some sub-region of sample space. In this paper it is assumed that the lifetimes of the items follow Truncated Logistic distribution truncated at point zero since time to failure of an item cannot be negative. Optimum step-stress PALT plan that finds the optimal proportion of units failed at normal use condition is determined by using the D-optimality criterion. The method developed has been explained using a numerical example. Sensitivity analysis and comparative study have also been carried out.

• Smart Structures and Systems
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• 제29권1호
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• pp.153-166
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• 2022

Identifying fine cracks in steel bridge facilities is a challenging task of structural health monitoring (SHM). This study proposed an end-to-end crack image segmentation framework based on a one-step Convolutional Neural Network (CNN) for pixel-level object recognition with high accuracy. To particularly address the challenges arising from small object detection in complex background, efforts were made in loss function selection aiming at sample imbalance and module modification in order to improve the generalization ability on complicated images. Specifically, loss functions were compared among alternatives including the Binary Cross Entropy (BCE), Focal, Tversky and Dice loss, with the last three specialized for biased sample distribution. Structural modifications with dilated convolution, Spatial Pyramid Pooling (SPP) and Feature Pyramid Network (FPN) were also performed to form a new backbone termed CrackDet. Models of various loss functions and feature extraction modules were trained on crack images and tested on full-scale images collected on steel box girders. The CNN model incorporated the classic U-Net as its backbone, and Dice loss as its loss function achieved the highest mean Intersection-over-Union (mIoU) of 0.7571 on full-scale pictures. In contrast, the best performance on cropped crack images was achieved by integrating CrackDet with Dice loss at a mIoU of 0.7670.

• 노동경제논집
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• 제40권2호
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• pp.31-68
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• 2017

본 연구는 그동안 우리나라에서는 연구가 상대적으로 미진하였던 부업에 관한 실증분석을 수행하였다. 25세부터 65세까지의 유배우자 임금근로자를 대상으로 분석한 결과, 부업 참여율은 1.4% 정도이고, 부업 참여자들은 주업에서 주당 40시간, 부업에서 20시간 등 주당 총 60시간의 장시간 근로를 하고 있는 것으로 나타났다. 부업 참여에 대한 고정효과 로짓 모델의 추정 결과에서는 주업의 시간당 임금 및 근로시간이 부업 참여에 부정적인 영향을 미치며, 주업의 일자리 안전성이 하락할수록 부업 참여 확률이 높아지는 것으로 분석되었다. 부업의 근로시간에 대한 고정효과 모형 분석 결과에서는, 주업의 근로시간은 부업의 근로시간에 부정적인 영향을 미치지만 주업의 임금은 부업의 근로시간에 유의한 영향을 미치지 않는 것으로 분석되었다. 흥미롭게도 부업의 임금이 증가할수록 부업의 근로시간은 감소하는 것으로 나타났는데, 이는 장시간 근로를 하고 있는 부업 근로자들의 상황 때문인 것으로 보인다.