• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.406-412
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• 1996

Optimal trajectory for a robot manipulator minimizing actuator torques or energy consumption in a fixed traveling time is obtained in the presence of obstacles. All joint displacements are represented in finite terms of Fourier cosine series and the coefficients of the series are obtained optimally by nonlinear programming. Thus, the geometric path need not be prespecified and the full dynamic model is employed. To avoid the obstacles, the concept of penalty area is newly introduced and this penalty area is included in the performance index with an appropriate weighting coefficient. This optimal trajectory will be useful as a geometric path in the minimum-time trajectory planning problem.

• 대한간호학회지
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• 제40권4호
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• pp.542-550
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• 2010

Purpose: This study was done to identify the factors which influence depression for elderly people who live at home. Methods: The participants were 134 elderly people living at home in M city. Data were collected from April 2 to 30, 2009 and analyzed using SPSS/WIN 12.0 and AMOS 5.0 program. I assumed path coefficients by doing path analysis to understand synthetically causal relationship which influences on depression. Results: Social support, sleep pattern and self esteem had significant direct effects on life satisfaction and accounted for 50% of the total variance in life satisfaction. Physical symptoms, sleep pattern and life satisfaction also had significant direct effects on depression and accounted for 59% of the variance in depression. But social support, self assertiveness and self esteem were not significant for depression. Conclusion: These results provide guidance for designing useful strategies to reduce depression in elderly people living at home.

• 한국정밀공학회지
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• 제14권3호
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• pp.147-155
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• 1997

Optimal trajectory for a robot manipulator minimizing actuator torques or energy consumptions ina fixed traveling time is obtained in the presence of obstacles. All joint displacements are represented in finite terms of Fourier cosine series and the coefficients of the series are obtained optimally by nonlinear programming. Thus, the geometric path need not be prespecified and the full dynamic model is employed. To avoid the obstacles, the concept of the penalty area is newly introduced and this penalty area is includ- ed in the performance index with an appropriate weighting coefficient. This optimal trajectory will be useful as a geometric path in the minimum-time trajectory planning problem.

• 대한기계학회논문집A
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• 제22권1호
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• pp.102-110
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• 1998

The analysis of lateral hydrodynamic forces in the leakage path between a shrouded pump impeller through wear-ring seal and its housing is presented. Governing equations are derived based on Bulk-flow and Hirs' turbulent lubrication model. By using a perturbation analysis and a numerical integration method, governing equations are solved to yield leakage and rotordynamic coefficients of force developed by the impeller shroud and wear-ring seal. The variation of rotordynamic coefficients of pump impeller shroud and wear-ring seal is analyzed as parameters of rotor speed, pressure difference, shroud clearance, wear-ring seal clearance, and circumferential velocity at the entrance of impeller shroud for a typical multi-stage centrifugal pump.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1306-1311
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• 2004

The performance test apparatus of liquid-phase plate heat exchanger was installed and the computer program for design was developed in this study. The detail temperature distribution of hot and cold fluids in each path of heat exchanger was calculated by numerical method and the correlation for the heat transfer coefficient was defined. The heat transfer coefficients were measured using the working fluids of water and glycerine to investigate the effect of fluid viscosity. The measured heat transfer coefficients were compared with the calculated values obtained from the computer program and it was shown that error of the calculated values was generally less than 5%.

• 전자공학회논문지A
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• 제33A권4호
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• pp.18-26
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• 1996

In this paper we propose a new dual structured tap selection algorithm for voice echo canceller in digital cellular communication system, investigating adaptive filtering algorithms for echo cancellation in long distance telephony or mobile communication system. The proposed algorithm has a two-stage processing structure that after a dispersive region in an impulse response of an echo path is found out, the tap coefficients of a short length filter are adjusted adaptively for the region, because the impuse response has a very little portion of the dispersion. Simulation results show that the proposed algorithm with 256 taps gives a performance of convergence speed superior to both full-tap normalized least mean with 256 taps gives a performance of convergence speed superior to both full-tap normalized least mean square (NLMS) and a scrub taps waiting in a queue (STWQ) algorithms by about eighty per cent, also to a tap selection algorithm by about twenty per cent. And the resutls diplay that if the more tap coefficients are used due to a long delayed dispersive zone, the proposed algorithm produces the better performance.

• Journal of electromagnetic engineering and science
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• 제17권1호
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• pp.39-43
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• 2017

In this paper, a systematic and statistical calibration technique was implemented to calibrate a high-speed signal converting system containing multiple digital-to-analog converters (DACs). The systematic error (especially the imbalance between DACs) in the current combining network of the multi-DAC system was modeled and corrected by calculating the path coefficients for individual DACs with wideband reference signals. Furthermore, by applying a Kalman filter to suppress noise from quantization and clock jitter, accurate coefficients with minimum noise were identified. For correcting an arbitrary waveform generator with two DACs, a co-simulation platform was implemented to estimate the system degradation and its corrected performance. Simulation results showed that after correction with 4.8 Gbps QAM signal, the signal-to-noise-ratio improved by approximately 4.5 dB and the error-vector-magnitude improved from 4.1% to 1.12% over 0.96 GHz bandwidth.

• Asian Journal of Business Environment
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• 제9권3호
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• pp.21-26
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• 2019

Purpose - This study aims to investigate the effect of brand image and trust of a home meal replacement (HMR) industry on customer satisfaction and repurchase during online shopping. Research design, data, and methodology - With 217 questionnaires, this study was conducted by AMOS 20.0, and the Structural Equation Model (SEM) as statistical method was used for examining the hypotheses in this study. Factors such as brand image and brand trust in customer shopping for HMR products online were tested, and relationships between satisfaction and repurchase were studied. Results - Brand image and brand trust in terms of online shopping for HMR were found to affect satisfaction significantly; in addition, the path where satisfaction leads to repurchase was found to be significant. However, brand image and brand trust for HMR in online shopping differed depending on customer age groups. The path-coefficients from brand image of HMR in online shopping to satisfaction were more significant in the older age group; meanwhile, the path-coefficient from brand trust to satisfaction was significant in the younger age group. Conclusions - Results of the study suggested the importance of the attributes for buying HMR products online and provided meaningful implications of difference between age groups when they choose the products.

• 지역사회간호학회지
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• 제27권4호
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• pp.399-409
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• 2016

Purpose: The purpose of this study was to analyze factors influencing health-related quality of life (HRQoL) among male adults. Methods: Participants were 196 male adults who were recruited from June to July 2016. Seven variables related to HRQoL including age, perceived stress, physical activities, problem drinking, social support, self-esteem, depression were measured. Data were analyzed using the SPSS/WIN 20.0 program and Amos 18.0 for descriptive statistics, Pearson correlation coefficients and path analysis. Results: The mean for HRQoL was 80.14. The path analysis showed that depression had the greatest direct effect on HRQoL. It was found that perceived stress had direct and total effects on HRQoL. It also mediated the paths of social support and self-esteem to HRQoL. These factors account for 68% of the total variance, and the fit indices of the model satisfied the criteria of fitness. Conclusion: The results indicate that these factors influencing HRQoL should be considered when developing programs to improve HRQoL for male adults.

• 지역사회간호학회지
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• 제29권2호
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• pp.184-193
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• 2018

Purpose: The aim of this study is to examine a path model on the relationship among social capital, physical activity and subjective health status in the community indwelling elderly. Methods: The study was conducted utilizing the 2014 Seoul Survey, in the method of analyzing cross-sectional design and secondary data. Among 45,497 participants in total, the data of 4578 adults aged 65 or above was analyzed. Social capital was measured by social trust and social participation. Physical activity was measured by regular exercise. Additionally, a numerical rating scale was used to assess subjective health status. The data were analyzed using descriptive statistics, Pearson's correlation coefficients and path analysis. Results: Social participation and physical activity showed a direct effect on subjective health status in community indwelling elderly while social trust and physical activity showed an indirect effect on their subjective health status. The hypothetical path model of community indwelling elderly's subjective health status was proved correct. Conclusion: Findings from this study indicate that health-promoting intervention for community indwelling elderly should consider social trust and participation.