• ETRI Journal
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• v.41 no.5
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• pp.637-647
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• 2019

Separating highly correlated users can reduce the loss caused by spatial correlation (SC) in multiuser multiple-input multiple-output (MU-MIMO) systems. However, few accurate analyses of the loss caused by SC have been conducted. In this study, we define signal-to-interference-plus-noise ratio (SINR) loss to characterize it in multiuser multiple-input single-output (MU-MISO) systems, and use coefficient of correlation (CoC) to describe the SC between users. A formula is deduced to show the accurate relation between SINR loss and CoC. Based on this relation, we propose a user selection method that utilizes CoC to minimize the average SINR loss of users in massive MU-MISO systems. Simulation results verify the correctness of the relation and show that the proposed user selection method is very effective at reducing the loss caused by SC in massive MU-MISO systems.

• Progress in Superconductivity and Cryogenics
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• v.25 no.4
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• pp.40-44
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• 2023

For high-temperature superconducting power applications that need large current capacity, a large current conductor manufactured using multiple superconducting tape is required. Conductors being studied for large currents capacity such as CORC, TSTC, and RACC have advantages and disadvantages, and in order to use these conductors in coil form and apply them to AC power devices, research on magnetization loss occurring in superconductors due to external magnetic fields is essential. To accurately measure magnetization loss in a conductor that is twisted by stacking straight conductors like TSTC, the correlation between the measuring system and the shape of the sample must be clearly known to accurately measure the loss. In this paper, we will confirm the difference in magnetization loss measurement values according to the correlation between the length of the pickup coil and the twist pitch of the sample in CORC and TSTC shapes, and review considerations for accurate magnetization loss measurement from the results.

• Journal of Distribution Science
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• v.15 no.11
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• pp.21-29
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• 2017

Purpose - Relationship between farm and county losses determines whether the county program provides too little, too much, or similar amount of assistance relative to the loss on an individual farm. A review of the literature finds limited analysis of the determinants of this relationship. This paper conducts such an analysis using farm-level yield data. Research design, data, and methodology - Farm-level yield data from Illinois and Kansas farm business management associations are used for to calculate the correlation between farm and county loss and the share of farm loss systemic with county loss, and also for the regression analysis. Results - Average share of farm loss systemic with the county loss lies between 42% and 68%. The correlation between farm and county yield/revenue deviation from expected value is statistically significant in all four models. The coefficient is positive, implying the higher the correlation, the larger the share of farm loss that is systemic with the county loss. Conclusions - The findings of this study are consistent with the existing literature which argues that county variability may not be closely associated with farm variability. The findings of this study thus raise questions about the efficacy of area yield and revenue insurance products in helping farmers manage their risk.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.1089-1098
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• 2008

The principal objective of this study was to reveal the relationship between the menu management indicators and menu performance indicators in contract-foodservice operations. Menu indicators differed according to the type of business, type of contract, type of serving, and number of service lines. In accordance with the results of our correlation analysis, we noted significant correlations between menu performance indicators and menu management indicators. The first of these was the correlation between the food cost ration and meal counts, food loss, and the use of prepared vegetables. The second of these was the correlation between food cost per meal and forecasting error, food loss, and inventory turnover. The last of these correlations was the negative correlation between menu CSI(customer satisfaction index) and the use of prepared vegetables. According to the results of our canonical correlation analysis, 2 significant functions were identified. In the first function, we noted significant correlations between meal counts, use of prepared vegetables, food loss, and food cost ratio. Additionally, we noted significant correlations between forecasting error, inventory turnover, food loss, and food cost per meal in the second function. Menu management indicators had no influence on customer satisfaction.

• Journal of Acupuncture Research
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• v.25 no.2
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• pp.189-197
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• 2008

Objectives : This study was performed in order to investigate the effectiveness of electromyography and the Heart Rate Variability(HRV) test as prognosis factors, and to clarify correlation between Electromyography and the Heart Rate Variability test. Methods : 44 Bell's palsy patients who were graded V on the House-Brackmann scale and underwent HRV and EMG testing were retrospectively reviewed based on medical records. Results from both tests were analyzed via simple linear regression, and bivariate correlation analysis was performed to investigate the correlation between results from the two tests. The severity of the facial palsy at onset and at 2 weeks after treatment were evaluated with the H-B grade and Yanagihara grading system, and was converted into improvement scores. Results : Mean axonal loss according to electromyography showed a statistically significant correlation in predicting peripheral facial palsy improvement(p<0.01). HR, SDNN, TP, LF, HF, VLF, and LF/HF ratio on the Heart Rate Variability test showed no significant correlation in predicting peripheral facial palsy improvement. Mean axonal loss determined by electromyography, and HR, SDNN, TP, LF, HF, VLF, and LF/HF ratio recorded with the Heart Rate Variability test was analyzed with the bivariate correlation analysis method. Mean axonal loss and SDNN showed a statistically significant correlation(p<0.01) Conclusions : The Heart Rate Variability test has no statistical significance in predicting peripheral facial palsy improvement. SDNN has a statistically significant correlation with mean axonal loss as determined by electromyography.

• Journal of Periodontal and Implant Science
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• v.23 no.2
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• pp.331-344
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• 1993

The purpose of this study was to investigate the change of tooth mobility and bite force according to periodontal disease severity. Tooth mobility and biting force due to change of viscoelastic property of periodontium were influenced by inflammation of periodontal tissue. 30 patients participated in this study, the periodontal disease severity is evaluated with SBI and attachment loss. SBI and attachment loss were examined by periodontal probe. Tooth mobility was tested two times to each tooth using periotest (Siemens Co, Germany) and bite force was evaluated with MPM-3000 (Nihon Kohden Co, Japan). Statistical analysis was applied to correlation ($r^2$) and regression analysis. The obtained results were as follows : 1. As the attachment loss increased, tooth mobility increased with significance, and they had highly positive correlation ($r^2=0.68$) on entire dentition. 2. As the SBI increased, tooth mobility increased with significance, and they had positive correlation ($r^2=0.37$) on entire dentition. 3. As the attachment loss increased, bite force decreased with significance, and they had highly negative correlation ($r^2=0.42$) on maxillary anterior dentition but low negative correlation ($r^2=0.20$) on the other portion of dentition. 4. As the SBI increased, bite force decreased with significance, and they had highly negative correlation ($r^2=0.31$) on maxillary anterior dentition but low negative correlation ($r^2=0.16$) on the other portion of dentition. 5. As tooth mobility increased, bite force decreased with significance, and they had highly negative correlation ($r^2=0.32$) on maxillary anterior dentition but low negative correlation ($r^2=0.16$) on the other portion of dentition.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.114-119
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• 2009

Field test was conducted to investigate primary factors reducing rapeseed harvesting using a reciprocating cutter-bar of combine. The results showed that the correlation between crop moisture content and yield loss had a U-type, which indicated that the yield reduction increased at too high and too low crop moisture contents. The proper ranges of crop moisture contents were 27${\sim}$35%, 21${\sim}$56%, and 62${\sim}$73% in case of grain, pod and stem, respectively. Crop moisture content was negatively correlated with header loss, but positively correlated with threshing loss. In contrary, stem moisture content showed positive correlations with total loss, threshing loss and separation loss. Working speed was positively correlated with header loss. Total flow rate, pod flow rate and stem flow rate were highly correlated with threshing loss and separation loss. However, grain flow rate did not show any correlation with total loss. According to the principal component analysis, two principal components were derived as components with eigenvalues greater than 1.0. The contribution rates of the first and the second components were 52.7% and 38.9%, which accounted for 91.6% of total variance. As a contributive factor influencing total loss of rapeseed mechanical harvesting, a crop moisture content factor was greater than a crop flow rate factor. The stepwise multiple regression analysis for total loss was conducted using crop moisture content factor, crop flow rate factor and coefficient. However, the model did not show any correlation among independent and dependent factors ($R^2$=0.060).

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.44-52
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• 2002

To understand the relationship among different quantitative traits, correlation studies were performed by utilizing eighty-eight inbred strains of silkworm, Bombyx mori L. on twelve economic characters. Analysis resulted in correlation of 5th instar period with total larval period (r ＝ 0.7882), cocoon weight with shell weight (r ＝ 0.8326), shell weight with shell ratio (r ＝ 0.5067), shell ratio with raw silk ％ (r ＝ 0.7570), raw silk ％ with filament length (r ＝ 0.3490), filament size (denier) with reelability (r ＝ 0.3193) and boil-off loss % (r ＝ 0.2792). Negative correlation was observed among filament length with filament size (r ＝ 0.7582) and reelability with boil-off loss % (r ＝ -0.3236). Correlation of different quantitative characters for quality silk production is discussed.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1298-1308
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• 2023

This study collected 245 questionnaires from college students in Gyeonggi-do and analyzed them using SPSS statistical packages, with the aim of identifying the status of hair loss perception due to the relationship between stress and hair loss received by college students and analyzing the correlation between stress and hair loss perception by type. As a result of the study, it was analyzed that the biggest problem caused by hair loss was 'loss of confidence', and in particular, people who were stressed about career/employment and studies were analyzed to consider the problem of 'loss of confidence' the most serious. As a result of cross-analysis of the general characteristics of awareness and the 'most recent stress' item, and as a result of correlation analysis between stress by type and hair loss status that constitutes hair loss awareness, it was analyzed that all types of stress affect hair loss in college students. Among them, career/employment stress and academic stress were found to be the most influential stress, and in the event of hair loss, it was analyzed that they were more willing to engage in hair loss treatment for career/employment, study, and appearance before interpersonal relationships or economic problems. Therefore, this study is of great significance in that it classified stress by type and analyzed the correlation through empirical research methods by specifying the contents of hair loss recognition into three categories: hair loss status, hair loss management, and hair loss treatment.

• Journal of Korean Academy of Nursing
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• v.41 no.6
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• pp.758-767
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• 2011

Purpose: This study was done to examine the threshold value of estimated height loss at which the risk of osteoporosis increases and to verify its discriminative ability in the detection of osteoporosis. Methods: It was conducted based on epidemiological descriptive methods on 732 Korean women at a public healthcare center in Seoul between July and November 2010. ANOVA, Pearson correlation, logistic regression analysis and receiver operating characteristics (ROC) curve were used for data analysis. Results: There was an age-related correlation between bone mineral density (lumbar spine: F=37.88, p<.001; femur: F=54.27, p<.001) and estimated height loss (F=27.68, p<.001). Estimated height loss increased significantly with decreasing bone mineral density (lumbar spine: r=-.23, p<.001; femur: r=-.34, p<.001). The odds ratio for the point at which the estimated height loss affects the occurrence of osteoporosis was found to increase at a cut-off value of 2 cm and the area under ROC curve was .71 and .82 in lumbar spine and femur, respectively. Conclusion: The optimal cut-off value of the estimated height loss for detection of osteoporosis was 2 cm. Height loss is therefore a useful indicator for the self-assessment and prognosis of osteoporosis.