• Investigative Magnetic Resonance Imaging
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• 제21권4호
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• pp.223-232
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• 2017

Purpose: To report the use of multiband accelerated echo-planar imaging (EPI) for resting-state functional MRI (rs-fMRI) to achieve rapid high temporal resolution at 3T compared to conventional EPI. Materials and Methods: rs-fMRI data were acquired from 20 healthy right-handed volunteers by using three methods: conventional single-band gradient-echo EPI acquisition (Data 1), multiband gradient-echo EPI acquisition with 240 volumes (Data 2) and 480 volumes (Data 3). Temporal signal-to-noise ratio (tSNR) maps were obtained by dividing the mean of the time course of each voxel by its temporal standard deviation. The resting-state sensorimotor network (SMN) and default mode network (DMN) were estimated using independent component analysis (ICA) and a seed-based method. One-way analysis of variance (ANOVA) was performed between the tSNR map, SMN, and DMN from the three data sets for between-group analysis. P < 0.05 with a family-wise error (FWE) correction for multiple comparisons was considered statistically significant. Results: One-way ANOVA and post-hoc two-sample t-tests showed that the tSNR was higher in Data 1 than Data 2 and 3 in white matter structures such as the striatum and medial and superior longitudinal fasciculus. One-way ANOVA revealed no differences in SMN or DMN across the three data sets. Conclusion: Within the adapted metrics estimated under specific imaging conditions employed in this study, multiband accelerated EPI, which substantially reduced scan times, provides the same quality image of functional connectivity as rs-fMRI by using conventional EPI at 3T. Under employed imaging conditions, this technique shows strong potential for clinical acceptance and translation of rs-fMRI protocols with potential advantages in spatial and/or temporal resolution. However, further study is warranted to evaluate whether the current findings can be generalized in diverse settings.

• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2182-2189
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• 2004

In the recent years, environmentally conscious design and manufacturing technologies have attracted considerable attention. The coolants, lubricants, solvents, metallic chips and discarded tools from manufacturing operations will harm our environment and the earth's ecosystem. In the present work, the Tukey method of multiple comparisons is used to select the minimum level of coolant required in a turning process. The amount of coolant is varied in 270 designed experiments and the parameters cutting temperature, surface roughness, and specific cutting energy are carefully evaluated. The effects of coolant mix ratio as well as the amount of coolant on the turning process are studied in the present work. The cutting temperature and surface roughness for different quantity of coolant are investigated by analysis of variance (ANOVA) - test and a multiple comparison method. ANOVA-test results signify that the average tool temperature and surface roughness depend on the amount of coolant. Based on Tukey's Honestly Significant Difference (HSD) method, one of the multiple comparison methods, the minimum level of coolant is 1.0 L/min with 2% mix ratio in the aspect of controlling tool temperature. F-test concludes that the amount of coolant used does not have any significant effect on specific cutting energy. Finally, Tukey method ascertains that 0.5 L/min with 6% mix ratio is the minimum level of coolant required in turning process without any serious degradation of the surface finish. Considering all aspects of cutting, the minimum coolant required is 1.0 L/min with 6% mix ratio. It is merely half the coolant currently used i.e. 2.0 L/min with 10% mix ratio. Minimal use of coolant not only economically desirable for reducing manufacturing cost but also it imparts fewer hazards to human health. Also, sparing use of coolant will eventually transform the turning process into a more environment-conscious manufacturing process.

• 한국콘텐츠학회논문지
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• 제12권9호
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• pp.211-216
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• 2012

이 연구에서는 경찰관의 조직적인 특성과 외상후 스트레스 장애 수준의 관계를 비교 분석하여 조직적 특성에 따른 외상후 스트레스 장애에 대한 영향을 확인하고자 하였다. 이를 위해 일원변량 분산분석(One-way ANOVA)을 실시하였다. 계급에 따른 외상후 스트레스 장애 수준에서는 유의미한 차이가 발견되지 않았는데, 경사, 순경 경장, 경위 이상 순이었다. 유의미한 수준은 아니지만 비간부 집단이 간부 집단보다 외상후 스트레스 장애 수준이 높게 나타났다. 근무관서에 따른 외상후 스트레스 장애 수준에서는 유의미한 차이가 발견되었는데, 지구대 파출소, 경찰서, 지방경찰청 순이었다. 이는 일선 경찰관서에서 근무하는 경우에 외상경험에 노출될 가능성이 높기 때문일 것이다. 근무부서에 따른 외상후 스트레스 장애 수준에서는 유의미한 차이가 발견되었는데, 생활안전, 수사 형사, 경비 교통, 내근 순이었다. 외근직이 외상경험에 노출될 가능성이 높기 때문에 내근직 보다 높게 나타났다. 근무기간에 따른 외상후 스트레스 장애 수준에서는 유의미한 차이가 발견되지 않았는데, 1년 이하, 2-10년, 11-19년, 20년 이상 순이었다. 특히 1년 이하 경찰관의 경우 외상후 스트레스 장애 수준이 상대적으로 매우 높게 나타났다. 근무하는 행정구역의 규모에 따른 외상후 스트레스 장애 수준에서는 유의미한 차이가 발견되지 않았고, 중소도시(50만 이상), 대도시(50만 이상), 광역시 이상, 군단위 이하 순으로 나타났다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.31-31
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• 2018

The purpose of this study was to statistically analyze amylose and protein content of rice variety resources collected from China (1,542), Japan (1,409), Korea (413), and India (287). The statistical analysis was conducted using ANOVA and DMRT based on the data obtained from NIRS analysis. The average amylose contents were 18.85% in Japanese, 19.99% in Korean, 20.27% in Chinese, and 25.46% in Indian resources. The average protein contents were 7.23% in Korean, 7.73% in Japanese, 8.01% in Chinese, and 8.17% in Indian resources. The amylose and protein content using ANOVA showed significant differences at the level of 0.01. The F-test for amylose content was 158.34, and for protein content was 53.95 compared to critical value 3.78. The amylose and protein content using DMRT (p<0.01) showed significant difference between countries. The value of statistical treatment was divided into three groups such as $China^a$, $Korea^a$, $Japan^b$, $India^c$ in amylose and $China^a$, $India^a$, $Japan^b$, $Korea^c$ in protein. Japanese resources had the lowest level of amylose contents, whereas, the lowest level of protein content was found in Korean resources compared to other origins. Indian resources showed the highest level of amylose and protein contents. It is recommended that these results could be helpful to future breeding experiments.

• 한국산업정보학회논문지
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• 제28권5호
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• pp.55-66
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• 2023

최근 국내 은행 산업은 인터넷전문은행, 오픈뱅킹, 금융 마이데이터 등의 제도가 시행되면서 디지털을 기반으로 하는 신규 시장 참여가 확대되고 있다. 이러한 새로운 경쟁 환경에 대응하기 위해 국내외 대부분의 은행들은 기존의 대면채널(지점)을 축소하고 인터넷, 모바일과 같은 비대면 채널을 활성화하는 방안을 추진하고 있다. 지점은 은행의 핵심 채널로 지점의 축소는 타 채널 이용에도 영향을 줄 수 있음에도 불구하고, 대부분의 은행들은 이에 대한 면밀한 분석 없이 지점을 축소하는 전략을 이어가고 있다. 본 연구는 은행의 다섯 가지 채널(창구, 자동화기기, 텔레뱅킹, 인터넷뱅킹, 모바일뱅킹)별 주 이용 고객의 특성과, 각 채널의 이용에 영향을 주는 요인을 분석한다. 이를 위해, A지방은행의 고객 데이터를 활용해 ANOVA 및 다중회귀분석을 수행한다. 분석 결과, 지점 창구 거래의 주 고객은 1, 2등급의 은행의 수익성에 영향이 큰 집단이고, 특히 50대 이상의 그룹인 것으로 확인되었다. 한편, 고객의 여신, 수신, 금융상품보유개수가 늘어날수록 창구거래도 늘어나는 영향을 주는 반면, 모바일뱅킹 이용에는 여신, 수신이 감소할수록 거래량이 늘어나는 것으로 확인 되었다.

• 유통과학연구
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• 제12권4호
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• pp.23-30
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• 2014

Purpose - The purpose of this study is to analyze the efficiency of retail businesses by dividing domestic retailers into discount stores, super supermarkets (SSMs), and department stores. It suggests retail-business investment strategies by using data environment analysis (DEA) to analyze how input elements such as store area, parking lot area, number of employees, and sales management expenses for the convenience of customers positively affect business performance measurements such as sales and visiting customers per day. Research Design, Data, and Methodology - The DEA model calculates a ratio of the weighted mean of various inputs to the weighted mean of various outputs and measures the efficiency of a specific decision making unit (DMU). The study included 19 companies (five discount store DMUs, ten SSM DMUs, and four department store DMUs). Because the business elements and sizes of retail store DMUs used in this analysis are different, average per-store input and output variables were used. Data were collected from "The Yearbook of Retail Industry in Korea (2012)." DEA analysis was used to determine differences in efficiency among discount stores, SSMs, and department stores in terms of the business elements of each retail business. It was also used to determine what business elements were excessively invested in by comparing and analyzing efficiency by business elements using SPSS software's ANOVA (Analysis of Variance). Results - The CCR and BCC efficiency analysis found that the efficiency of discount stores is low. We believe that the saturation state of discount stores is a major factor. The ANOVA analysis confirms the VRS hypothesis with a statistically significant difference among the three groups, based on an analysis confidence interval of 95%. CRS and SE were not found to be significantly different among the three groups. As for the post hoc test, which concretely shows differences by group, the Scheffe's multiple comparison analysis test found the average differences between group 1 (discount stores) and group 2 (SSM) to be statistically significant. Conclusions - The DEA efficiency analysis implies that investment in input elements, including store area, parking lot area, and sales management expenses, were excessive in the case of discount stores, while SSMs need to invest more in promotion activities such as gifts, events, and coupons for customer management. Department stores have found that small companies invest excessively in input elements. Department stores need to invest in differentiated shopping mall complexes. This study was limited in acquiring statistical data; various input variables which might have shown more secure customer management and promotional expenses could not be applied. As the study was limited in various aspects of the efficiency analyses because financial analyses of the companies and of causal relationships, including satisfaction and loyalty of visiting customers, were not done, these aspects will be examined in the next study.

• Journal of Periodontal and Implant Science
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• 제30권3호
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• pp.699-707
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• 2000

The purpose of this study was to analyze the statistical errors of articles in the Journal of Korean Academy of Periodontology from 1973 to 1999. Of the 662 articles examined, 263 were included which analyzed the data. They were classified into 2 groups with time lapse; group 1: 1973∼1989, group 2: 1990∼1999. Authors made checklists for analyzing the data and detecting the errors and analyzed them with professional statistician. The results were as follows: 1. Of 263 atricles which applied statistical method, 40(19.3%) was in group 1, 223(49.0%) in group2. 2. In the number of statistical method applied, 170(64.6%) were analyzed with 1 statistical method, 73(27.8%) with 2 methods, 18(6.8%) with 3 methods, and 2(0.8%) with 4 methods 3. The number of statistical methods applied was 14, and they were applied in order of 119 of ANOVA, 72 of Student t-test, 63 of Paired t-test, 36 of CORRELATION, and 21 of Mann- Whitney U test. 4. In 87(33.1%) of 263 articles and in 18 error items, statistical errors were found out. In group I, 9 items (55%) of error were found out, and were in order of 5 of Student t-test instead of Paired t-test, and 4 of unnecessary statistical analysis. In group II, 16 items (29.1%) of error were found out, and were in order of 22 of Student t-test instead of Paired t-test, 7 of no multiple comparison test after ANOVA, 6 of Student t-test instead of ANOVA, 6 of unnecessary statistical analysis, and 5 of ANOVA instead of Paired t-test. In conclusion, the results noted that statistical analyses were increased, but statistical errors were decreased with time. But authors suggest that researchers should refer to standard statistical texts and seek advice from professional statisticians to avoid the statistical errors.

• 한국안전학회지
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• 제21권4호
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• pp.127-133
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• 2006

이 논문의 주요 목적은 안전 분위기를 확인하여 공장과 근로자의 안전문화 수준에 영향을 주는 변수들을 찾아내고 더 나아가 화학공장의 안전문화를 향상시킬 수 있는 영향요소를 찾는데 있다. 이 논문에 사용된 질문표는 영국의 HSE(Health and Safety Executive) 의 질문표를 근간으로 문헌 조사를 통하여 경영자와 근로자로 분류하여 개발하였다. 안전문화 수준을 확인하기 위해 빈도수 분석을 하였으며 공장규모, 사고 발생, 사고 및 상해 경험과 심각성, 그리고 고용기간 등과 같은 영향변수들은 ANOVA(Analysis of Variance) 분석을 적용하여 테스트하였다. 빈도수 분석의 결과 일반적으로 경영자와 근로자 모두가 안전문화의 수준이 높게 나타났으며 주된 문제점들로는 부적당한 안전 보건 절차와 규칙, 생산에 대한 압력, 그리고 규칙위반으로 나타났다. 또한 ANOVA 분석결과에 의하면, '고용기간'은 다른 안전 문화의 수준을 만드는 유일한 변수인 것으로 나타났다. 그리고 안전문화의 조사로부터 공장들의 안전 문화요소에 대한 주요 3가지 문제점과 안전문화수준을 발견하였으며 안전 이행 능력을 향상시킬 수 있는 2가지 영향요소를 제안하였다.

• 기술혁신연구
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• 제5권1호
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• pp.44-66
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• 1997

This study is a critical assessment of research productivity through publication among scientists and engineers. Through the analysis of the 223 mail questionnaires collected from professors of mechanical engineering, electrical engineering, chemistry and physics, this study obtains the particular determinants of publication productivity at the science and engineering schools in Korea. The data are analyzed using correlation, ANOVA, multiple regression analysis and path analysis. The result shows that early research productivity and the number of doctoral students are very important to publish good research articles. Also the qualities of professors' Ph.D. institution and the quality of employing university are critical influencing factors to publication productivity.

• 한국정밀공학회지
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• 제24권3호
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• pp.84-90
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• 2007

As a result of vehicle maintenance of rocker arm shaft for 4-cylinder SOHC engine, failure stress analysis of rocker arm shaft is needed. Because more than 30% of vehicles investigated have been fractured. Failure stress analysis is classified into an naked eyes, microscope, striation and X-ray fractography etc. Failure stress analysis by using striation is already established technology as means for seeking cause of fracture. But, although it is well known that striation spacing corresponds to the crack growth rate da/dN, it is not possible to determine ${\sigma}_{max}\;and\;{\sigma}_{min}$ under service loading only from striation spacing. This is because the value of striation spacing is influenced not only by ${\Delta}K$ but also by the stress ratio R. In the present paper, we determine the stress ratio using orthogonal array and ANOVA, and propose a prediction method of failure stress which is combined with FEM and striation.