• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.253-271
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• 2017

In this paper, considering that perfect channel state information (CSI) is hard to achieve in practice, the downlink capacity of distributed antenna systems (DAS) with imperfect CSI and multiple receive antennas is investigated over composite Rayleigh fading channel. According to the performance analysis, using the numerical calculation, the probability density function (PDF) of the effective output SNR is derived. With this PDF, accurate closed-form expressions of ergodic capacity and outage probability of DAS with imperfect CSI are, respectively, obtained, and they include the ones under perfect CSI as special cases. Besides, the outage capacity of DAS in the presence of imperfect CSI is also derived, and a Newton's method based practical iterative algorithm is proposed to find the accurate outage capacity. By utilizing the Gaussian distribution approximation, another approximate closed-form expression of outage capacity is also derived, and it may simplify the calculation of accurate outage capacity. These theoretical expressions can provide good performance evaluation for downlink DAS for both perfect and imperfect CSI. Simulation results verify the effectiveness of the theoretical analysis, and the system capacity can be improved by increasing the receive antennas, and decreasing the estimation error or path loss. Moreover, the system can tolerate the estimation error variance up to about 0.01 with a slight degradation in the capacity.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.56-61
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• 2014

Two erosive burning models were applied to compare analysis results of ballistic for the internal ballistics of solid rocket motors. By comparing motor tests with results of analysis, the variance of a grain shape was analyzed and coefficients of erosive burning were drawn. Results of comparison presents that the coefficient of erosive burning was proportional to the change of burning area, while inversely proportional to the change of cross area.

• Journal of muscle and joint health
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• v.14 no.1
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• pp.33-41
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• 2007

Purpose: The purpose of the study was to identify the pain patterns and factors affecting low back pain in middle-aged women with backache. Method: A descriptive research design was utilized. The participants were middle-aged women who visited to two back pain clinics in Wonju from October, 2006 through February, 2007. A total of 195 low back pain patients agreed to participate in this study, and data from 177 were analyzed. Data were collected using a questionnaire which included a modified short-form Korean pain rating scale, demographic factors, factors related to low back pain and health behavior. Descriptive statistics and multiple regression analysis was utilized in the analysis. Results: The mean score for low back pain was relatively low(M=21.57, SD=11.44). Among pain patterns, scores for dull pain were the highest of all the dimensions. In the regression analysis, significant factors affecting low back pain were found to be age, level of education, religion, BMI, experience of pregnancy, delivery type and exercise. These variables explained 24.8% of variance in low back pain(F=3.79, p<.001). Conclusion: These results suggest that nurses need for assessment and intervention to take into consideration pain patterns as well as factors affecting middle-age women with backache.

• The KSFM Journal of Fluid Machinery
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• v.16 no.4
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• pp.22-27
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• 2013

The purpose of this paper is to perform the structural design of the small scale vertical-axis wind turbine (VAWT) blade using a response surface method(RSM). First, the four design factors that have a strong influence on the structural response of blade were selected. Analysis conditions were calculated by using the central composite design(CCD), which is a typical design of experiment for the response surface method(RSM). Also, the significance of the central composite design(CCD) was verified using analysis of variance(ANOVA). The finite element analysis was performed for the selected analytical conditions for the application of response surface method(RSM). Finally, a optimization problem was solved with a objective function of blade weight and a constraint of allowable stress to achieve a optimal structural design of blade.

• Journal of the Korean Society of Food Culture
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• v.31 no.6
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• pp.624-633
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• 2016

This study identified the sensory properties of samples of pizza dough at three pizza companies and three masonry oven pizzerias from Seoul, Korea and compared consumer acceptability among panels of university students. Six pizza dough samples were prepared (pan pizzas from Pizza Hut, Mr.pizza, and Dominos pizza, masonry oven baked pizzas from Appleteen, Mr.Lee's, and Pizza factory). Consumer tests were employed involving 97 Korean consumers. Consumers evaluated overall liking (OL), liking of appearance (APPL), odor (ODL), flavor (FLL), and texture (TXTL), willing to try (WT), and willing to recommend (WR) for the samples using a nine-point hedonic scale. Analysis of variance (ANOVA) indicated that HutP, MrP, and DomP samples had significantly (p<0.05) high scores for roughness, porosity, crust color, grain size, brownness, dairy food aroma, savory taste, and yeast aroma, which had the highest OL, ODL, and FLL scores. LeeP, ATeenP, and PFacP samples had high elasticity, cohesiveness, and adhesiveness. Consumers favored the appearance characteristics and color, dairy product flavor, and savory flavor of the pan pizza and preferred cohesiveness, toughness, and stickiness of masonry oven baked pizza.

• Journal of Fashion Business
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• v.25 no.4
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• pp.79-91
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• 2021

Currently, chatbot, a conversational platform based on artificial intelligence, is drawing attention as a new marketing channel. This study attempted to verify the effect of the anthropomorphism, message type, and media self-efficacy level on purchase intention. The experimental design of this study was a 2 (anthropomorphism level of shopping chatbot: low vs. high) × 2 (message type: factual vs. evaluative) × 2 (media self-efficacy: low vs. high) three-way mixed analysis of variance (ANOVA). This study conducted a survey by the convenience sampling method of 402 women in their 20s and 30s living in Seoul and the Gyeonggi area who were aware of chatbot services. For the final analysis, 388 questionnaires were used. Data were analyzed with the SPSS 23 program and three-way ANOVA. Simple main effects analysis was conducted. The results of this study were as follows. First, there were statistically significant differences in purchase intention according to anthropomorphism level, message type, and media self-efficacy. Second, message type and media self-efficacy showed statistically significant interaction effects on purchase intention. Lastly, anthropomorphism and the media self-efficacy level and the message type of the shopping chatbots showed significant three-way interaction effects on purchase intention.

• The Journal of the Acoustical Society of Korea
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• v.40 no.4
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• pp.290-296
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• 2021

The purpose of this study was to examine the perceived emotion of music according to cognitive styles of music listening. A total of 91 music-related graduate students participated in this study. They were given a questionnaire about perceived emotions of music, musical elements, and Music Empathizing-Music Systemizing Inventory. To analyze statistically, Descriptive statistics, paired t-test, ANalysis Of VAriance (ANOVA), multi-variate analysis, and Pearson correlation analysis were conducted. Results showed that participants had relatively universal experience in perceived emotions of both types of music, and also showed that musical elements contributed to the experience differed by cognitive styles of music listening.

• Journal of Home Health Care Nursing
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• v.27 no.3
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• pp.271-283
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• 2020

Purpose: This study aimed to develop a scale measuring the Tae-Wom in nurses. Methods: The initial items were based on an extensive literature review and in-depth interviews with seven nurses with varied careers. Thirty-five items were derived from a pilot survey. Data were collected from 196 hospital nurses, and analyzed to identify items of the scale as well as to verify the exploratory factor analysis, reliability, and validity of the scale. Results: The results of the exploratory factor analysis showed that six factors contained 26 items and 65.2% of the total explained variance. These six factors comprised negative behavior exhibited by the Tae-Wom recipient, personal character of the Tae-Wom giver, personal character of nursing unit managers, work attitude of the Tae-Wom giver, overwhelming workload, and unskilled relationships. Furthermore, convergent and discriminant validity testing verified these items. The internal consistency reliability was acceptable (Cronbach's α= .93), and Cronbach's α for each factor ranged from .62 to .90. Conclusion: The developed Tae-Wom scale will serve as a tool for verifying the Tae-Wom state in nursing organizations. Therefore, this scale is expected to mitigate the negative effects of the Tae-Wom.

• Korean Journal of Exercise Nutrition
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• v.24 no.2
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• pp.38-46
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• 2020

[Purpose] This study aimed to investigate the effects of leucine-enriched essential amino acid (LEAA) supplementation on muscle fatigue and the level of inflammatory cytokines in wheelchair basketball players after a basketball game and interval training. [Methods] Of the ten recruited wheelchair basketball players (aged 34.5±8.9 years; lean body mass of 34.3±10.0 kg) who had spinal cord injury (SCI) and had undergone amputation, nine participated in the final test. These nine athletes received LEAA supplements (3 times 4.0 g/day) or placebo treatment in a double-blind, randomized, crossover study. We measured variables related to muscular fatigue and inflammatory response before the intense exercise and 4 days after recovery. [Results] The significant effect of LEAA supplementation was inhibition of circulating IL-6 levels in the LEAA-treated group compared with the placebo group (P < .05). However, no changes were observed in the TNF-α and creatinine kinase levels. Moreover, analysis of variance analysis showed no significant difference in the relative values of muscle soreness. However, the effect size analysis with Cohen's d reported a significant improvement in the relative values of whole body and back muscle soreness. [Conclusion] Our results revealed that LEAA supplementation before and after intense exercise could help reduce muscle soreness and IL-6 levels in wheelchair basketball players.

• Journal of Korean Academy of Nursing
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• v.44 no.6
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• pp.630-638
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• 2014

Purpose: The purpose of this study was to develop a scale to evaluate stress in elderly patients with coronary artery diseases (CAD) and to examine validity and reliability of the scale. Methods: The development process for the preliminary scale included construction of a conceptual framework and initial items, verification of content analysis, sentence correction, and pilot study. This study was conducted using a questionnaire survey with one-to-one interviews during January and February, 2012. Participants were 240 elderly patients with CAD. Data were analyzed using item analysis, factor analysis, criterion related validity, and internal consistency. Results: The developed scale consisted of 32 items and 6 factors - aging and disease (7 items), family relations (5 items), anxiety and withdrawal (9 items), management of daily living (3 items), compliance of medical regimen (4 items), poverty and finance (4 items), and explained 68.5% of total variance. The scale had significantly positive correlation with the Korean Perceived Stress Scale (KPSS). Cronbach's alpha was .96, and Guttman split half coefficient was .91. Conclusion: Results indicate that the Stress Scale for Elderly Patients with CAD has validity and reliability, and is a suitable scale in health care settings to assess stress in elderly patients with CAD.