• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.78-82
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• 2011

Ventilation rates, inside and outside weather data were measured in a arch-shape single-span plastic greenhouse growing tomatoes. On the roof of the experimental greenhouse, round windows which have a diameter of 0.6 m were installed at intervals of 8m. It showed that the number of air changes in this greenhouse were average 0.17 volumes per minute and in the range of 0.02 to 0.32 volumes per minute. These air changes are insufficient to meet the recommended ventilation rate for commercial greenhouses, and it is estimated that interval of 6 m is appropriate for spring or fall season. For summer season, it is necessary to narrow the space or to enlarge the open area of roof windows. Using the heat balance model, the evapotranspiration coefficients of greenhouse tomatoes were estimated from experimental ventilation data, overall heat transfer and solar radiation. It showed that the evapotranspiration coefficients were average 0.62 and in the 0.39 to 0.85 range. We suggest applying 0.6 as the evapotranspiration coefficient in design of ventilation for the single-span tomato greenhouses.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.51-63
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• 2023

Riverine tree management is crucial in realizing a balance between flood control and ecological preservation, which requires an accurate assessment of the impact of trees on river water elevations. In this study, eight different formulas for evaluating vegetation roughness considering the drag force acting on trees, were reviewed, and the characteristics and applicability of these methods were evaluated from a practical engineering perspective. The study compared the characteristics of vegetation roughness measurement methods for calculated roughness coefficients at different water depths and analyzed factors such as effects of tree canopy width, tree density and diameter, and tree stiffness coefficient, and water level estimation results. A comparison of roughness coefficients at the same water depths revealed that the Kouwen and Fathi-Moghadam formulas and the Fischenich formula yield excessive drag coefficients compared to other formulas. Factors such as channel geometry, tree diameter, and tree density showed varying trends depending on the formula but did not exhibit excessive outliers. Formulas considering the tree stiffness coefficient, such as the Freeman et al.'s formula and the Whittaker et al.'s formula, showed significant variations in drag coefficients depending on the stiffness coefficient. When applied to small- and medium-sized virtual rivers in South Korea using the drag coefficient results from the eight formulas, the results indicated a maximum increase in water level of approximately 0.2 to 0.4 meters. Based on this review, it was concluded that the Baptist et al., Huthoff et al., Cheng, Luhar, and Nepf's formulas, which exhibit similar characteristics and low input data uncertainties, are suitable for practical engineering applications.

• The Korean Fashion and Textile Research Journal
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• v.16 no.6
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• pp.979-986
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• 2014

This study establishes basic data for operations management by organizing processes and measuring time in the mini line for female jackets to improve productivity, ensure competitiveness, and maintain operator competency and the line process flow balance between apparel manufacturing companies. The results of this study are as follows. Sewing operations are divided into preparation functions, arrangement, partial tasks, and assembly that consist of 84 processes. The results from time measurement indicate that 3238.41seconds (sec) were required to produce a single jacket and that the average time required for operators was 231.32 sec. A control limit was established to increase the reliability of the measured value for net time. After outside values were removed, the operation time was measured to be 3176.35 sec. This accounted for 98.08% of the total operation time, with net time decreasing by 62.06. Skill and effort level coefficients were applied to measure the operator performance, the total real time was calculated to be 3415. The requirement for preparation and arrangement operations were 1233.35 sec, and 2182.22 sec for partial tasks and assembly operations. Process separation and organization were performed after the bottleneck operation was selected to identify the maximum line balance. Consequently, process efficiency of preparation and arrangement operations increased from 79.19% to 93.00%, and the partial tasks and assembly operations increased from 62.36% to 90.93%.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.7
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• pp.339-349
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• 2001

This paper suggests an optimal identification method for complex and nonlinear system modeling that is based on Fuzzy-Neural Networks(FNN). The proposed Hybrid Identification Algorithm is based on Yamakawa's FNN and uses the simplified inference as fuzzy inference method and Error Back Propagation Algorithm as learning rule. In this paper, the FNN modeling implements parameter identification using HCM algorithm and hybrid structure combined with two types of optimization theories for nonlinear systems. We use a HCM(Hard C-Means) clustering algorithm to find initial apexes of membership function. The parameters such as apexes of membership functions, learning rates, and momentum coefficients are adjusted using hybrid algorithm. The proposed hybrid identification algorithm is carried out using both a genetic algorithm and the improved complex method. Also, an aggregated objective function(performance index) with weighting factor is introduced to achieve a sound balance between approximation and generalization abilities of the model. According to the selection and adjustment of a weighting factor of an aggregate objective function which depends on the number of data and a certain degree of nonlinearity(distribution of I/O data), we show that it is available and effective to design an optimal FNN model structure with mutual balance and dependency between approximation and generalization abilities. To evaluate the performance of the proposed model, we use the time series data for gas furnace, the data of sewage treatment process and traffic route choice process.

• The Journal of Korean Medicine
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• v.37 no.3
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• pp.27-38
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• 2016

Objectives: According to Korean Medicine theory, the skin color of LU10 serves as a diagnostic clue to dyspeptic symptoms. The aims of this study were (1) to find the difference of skin color in LU10 region between functional dyspepsia (FD) and healthy control (HC) and (2) to examine the relationship between LU10 skin color parameters and dyspeptic symptoms. Methods: 39 participants (29 FD and 10 HC) have participated in this study. They were asked to complete gastrointestinal scale (GIS), gastrointestinal symptom rating scale (GSRS), Nepean dyspepsia index (NDI), functional dyspepsia-related quality of life (FD-QoL), visual analogue scale (VAS) for dyspeptic symptoms, food retention questionnaire (FRQ) and cold heat questionnaire (CHQ). $L^*$ (luminance), $a^*$ (red-green balance) and $b^*$ (yellow-blue balance) values of LU10 region were calculated through digital images of the participant's hand. Then we evaluated test-retest reliability of $L^*$, $a^*$ and $b^*$ values of LU10 region. Additionally, we compared $L^*$, $a^*$ and $b^*$ values of LU10 between FD and HC, and examined the relationship between LU10 color parameters and seven questionnaires scores. Results: Only $L^*$ values in LU10 region were significantly higher in FD compared with HC. GIS scores and the subset scores of NDI had a positive correlation with $L^*$ values significantly. Correlation coefficients of test-retest reliability of skin color measurement of LU10 ranged from 0.871 to 0.936 representing very strongly statistically significant (P<0.001). Conclusions: We confirmed the difference of skin color in LU10 region between FD and HC, and relationship between LU10 skin color parameters and dyspeptic symptoms.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.607-612
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• 2007

In this study, we investigated the variations of the kinetic coefficients and Chemical Oxygen Demand (COD), N and P mass used for assimilation of a sequencing batch reactor (SBR) system with the variation of SRTs; SRTs of 7.5, 10.0, 12.5, 15.0 and 20.0 days were tested in one cycle of SBR operation to determine the optimum conditions for the operation of the SBR and estimate its COD, nitrogen and phosphorus removal efficiencies. The SBR system was operated under the conditions as follows: an operation time of 6 hours per cycle, a hydraulic retention time (HRT) of 12 hours, an influent COD loading of $0.4kg/m^3/day$, and an influent nitrogen loading of $0.068kgT-N/m^3/day$. The yield coefficient (Y) and decay rate coefficient ($k_d$) were estimated to be 0.4198 kgMLVSS/kgCOD and $0.0107day^{-1}$ by calculating the removal rate of substrate according to the variation of SRT. Considering total nitrogen amount removed by sludge waste process, eliminated by denitrification, and in clarified water effluent with reference to 150 mg/cycle of influent nitrogen amount, the percentage of nitrogen mass balance from the ratio of the nitrogen amount in effluent (N output) to that in influent (N input) for Runs 1~5 were 95.5, 97.0, 95.5, 99.5, and 95.5%, respectively, which is well accounted for, with mass balances close to 100%.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.10 no.1
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• pp.47-61
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• 2015

Objectives : The purpose of this study is body parameters characteristics through posture analysis system of musculoskeletal problem patient Methods : Posture analysis system were performed for 164 patients to measure body parameters such as Q-angle, body inclination, neck inclination, PCMT(posterior cervical muscle tension), Knee flexion and posture balance. Statistical analysis using statistical analysis techniques and Pearson correlation coefficients was performed to assess the body parameters obtained by posture analysis system. Results : More than half of people out of 164 reported low back pain, 34.8% of the total was found to have neck pain. There was not a significant difference between genders from the characteristics of gender based body parameters expect for the statistical difference in Q angle, PCMT. There was a significant correlation between low back pain and multiple response status. There was a significant correlations between knee pain and Q angle. Also There was a significant correlations between pelvic pain and posture balance of ankle. Conclusions : Posture analysis system can be used to perform the analysis in place of X-ray measuring body posture and clinical parameters. The results of this study are expected to be the basis for further research on the clinical application of posture analysis system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.468-477
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• 2014

In this research, how a solar powered HALE (high altitude long endurance) UAV (Unmanned Aerial Vehicle) can climb and reach mission altitude, 18km, starting from the ground using only solar energy. A glider type aircraft was assumed as a baseline configuration which has wing area of $35.98m^2$ and aspect ratio of 25. Configuration parameters, lift and drag coefficients were calculated using OpenVSP and XFLR5 that are NASA open source programs, and climb flights were predicted through energy balance between available energy from solar power and energy necessary for a climb flight. Minimum time climb flight was obtained by minimizing flight velocities at each altitude and total time and total energy consumption to reach the mission altitude were predicted for different take off time. Also, aircraft moving distances due to westerly wind and flight speed were calculated.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.1
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• pp.29-37
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• 2012

Purpose : The purpose of this study was to establish intra-rater, inter-rater, test-retest reliability, and concurrent validity of figure-of-8 walk test in people with stroke. Methods : The subjects of this study were 17 patients who were diagnosed with a stroke. Subjects were tested twice by the same raters, with 1 day between tests. Subjects were assessed by two physical therapists. Test-retest reliability was calculated using intraclass correlation coefficients (ICC). The concurrent validity was demonstrated by spearman correlation of F8WT with 10m walking test (10MWT), timed up and go test (TUG), Berg balance scale (BBS), dynamic gait index (DGI) and four square step test (FSST). Results : Intra-rater, inter-rater, test- retest of F8WT time, showed high reliability. Intra-rater, inter-rater, test-retest of F8WT steps demonstrated high reliability. Intra-rater, inter-rater, test-retest of F8WT total smoothness score showed below moderate reliability. There was a significant positive correlation of F8WT time with 10MWT, TUG, FSST. There was a significant negative correlation of F8WT time with DGI, BBS. There was a significant positive correlation of F8WT steps with 10MWT, TUG, FSST. There was a significant negative correlation of F8WT steps with DGI. There was a significant positive correlation of F8WT test total smoothness score with BBS. Conclusion : The time, and number of steps in F8WT show high inter, intra-rater, test-retest reliability. The F8WT smoothness shows below moderate reliability. The F8WT shows high concurrent validity with other comparable balance, and walking tests. The F8WT is a valid and reliable measure for assessing walking function in patients with a stroke.

• Journal of Korean Academy of Nursing
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• v.49 no.4
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• pp.386-397
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• 2019

Purpose: This study examined the effect of hospitals' family-friendly management on married female nurses' retention intention. The focus was the mediating effects of the work-family interface (work-family conflict, work-family enrichment and work-family balance). Methods: This study was a cross-sectional study. The participants were 307 nurses working at five public and five private hospitals with more than 200 beds in Seoul. Data were collected using structured questionnaires from September 10 to September 17, 2018 and analyzed with SPSS 24.0. Data were analyzed using an independent t-test, a one-way ANOVA, Pearson's correlation coefficients, and multiple regression following the Baron and Kenny method and Sobel test for mediation. Results: There were significant correlations among family-friendly management, the work-family interface, and retention intention. Work-family conflict showed a partial mediating effect on the relationship between family-friendly management and retention intention. Work-family enrichment showed a partial mediating effect on the relationship between family-friendly management and retention intention. Work-family balance showed a partial mediating effect on the relationship between family-friendly management and retention intention. Conclusion: These findings indicate that both hospitals' family-friendly management and nurses' work-family interface are important factors associated with nurses' retention intention. Therefore, hospitals should actively implement family-friendly management for nurses and establish strategies to enhance nurses' work-family interface for effective human resource management.