• International Journal of Automotive Technology
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• v.8 no.4
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• pp.521-531
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• 2007

Measurement of the vibration transmitted through rotating shafts such as half shafts in vehicles is of interest in applications such as noise transfer analysis and the study of operating deflections. Vibration signals transmitted through a rotating shaft usually include six degree-of-freedom components, thus making the measurement of vibration a challenging task. In the present work, a new measurement method is presented, one that resolves the minimum of only two one-axis accelerometer signals into all components of vibration with reasonable accuracy. The method utilizes the Dopplerized signals obtained from accelerometers attached to a rotating shaft and a Void-Kalman order tracking filter to decompose signals into orders of different vibration components. The new method proposed in the present work is verified by simulated run-up test data and applied to an experimentally obtained data set.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.6
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• pp.287-293
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• 2005

Equations have been derived for computing electromagnetic forces by using the Continuum Design Sensitivity Analysis based on the Continuum Mechanics and the Virtual Work Principle. The resultant expressions have similar terms relating to the Korteweg-Holmholz force density, Maxwell Stress Tensor and Magnetic Charge Method but numerical implementation of the proposed scheme leads to efficient calculation and improved accuracy. In addition, the method can be easily applied to computing the magnetic force distribution as well as the global force. Results show the aforementioned advantages in comparison with the conventional methods.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.2
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• pp.299-306
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• 1996

This work presents an analytical model, so called modified LMTD method, to predict the thermal performance of finned-tube heat exchanger under frosting conditions. In this model, the total heat transfer coefficient and effective thermal conductivity of the frost layer were defined as a function of frost surface temperature. The surface temperature of the frost layer formed on the heat exchanger was calculated through the analysis of the heat and mass transfer process in the air and frost layer. To examine the validity of this analytical model, the computed results from the present model, such as heat transfer rate, frost mass and thickness of frost, were compared with the ones of the expermental work and LMED method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.3 s.246
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• pp.302-309
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• 2006

Effective mixing plays a crucial role in microfluidics for biochemical applications. Owing to the small device scale and its entailing the low Reynolds number, the mixing in microchannels proceeds very slowly. In this work, we optimize the configuration of obstacles in the Y-channel mixer in order to attain maximum mixing efficiency. Before the optimum design, mixing characteristics are investigated using unstructured grid CFD method. Then, the analysis method is employed to construct the approximate analysis model to be used in the optimization procedure. The main optimization tool in the present work is sequential quadratic programming method. Using this approximate optimization procedure, we may obtain the optimum layout of obstacles in the Y-channel mixer in an efficient manner, which gives the maximum mixing efficiency.

• Journal of Urban Science
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• v.9 no.2
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• pp.51-56
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• 2020

The installation of soft ground instruments and the performance of measurement and management of the measurement shall be carried out in order to ensure the safety of the construction work and to improve the quality of the construction work. The purpose of the pressure density deposition calculation is to determine the stability of the foundation ground and the formulation by measuring and calculating the density conditions generated on the soil through the period of neglect after completion of the soil at each stage. In practice, it is judged that the analysis by the hyperbolic method can be applied to the safety side.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.517-522
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• 2000

When a body including a crack inside is subjected to the compressive forces, the crack is closed and sliding occurs on the crack surfaces. In this work, a subsurface crack subjected to a static or moving compressive load is analyzed with the finite element method considering friction on the crack surface. The friction on the crack surface is assumed to follow the Coulomb friction law. A numerical method based on the finite element method and iterative method is applied in this work. And the result is compared with the frictional contact of crack by ANSYS using contact 12 element. The numerical results of two methods are compared with the wellknown analytical solutions, and the accuracy of iterative method is checked..

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8371-8376
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• 2014

Background: The use of statistical methods has become an imperative tool in breast cancer survival data analysis. The purpose of this study was to develop the best statistical probability model using the Bayesian method to predict future survival times for the black non-Hispanic female breast cancer patients diagnosed during 1973-2009 in the U.S. Materials and Methods: We used a stratified random sample of black non-Hispanic female breast cancer patient data from the Surveillance Epidemiology and End Results (SEER) database. Survival analysis was performed using Kaplan-Meier and Cox proportional regression methods. Four advanced types of statistical models, Exponentiated Exponential (EE), Beta Generalized Exponential (BGE), Exponentiated Weibull (EW), and Beta Inverse Weibull (BIW) were utilized for data analysis. The statistical model building criteria, Akaike Information Criteria (AIC), Bayesian Information Criteria (BIC), and Deviance Information Criteria (DIC) were used to measure the goodness of fit tests. Furthermore, we used the Bayesian approach to obtain the predictive survival inferences from the best-fit data based on the exponentiated Weibull model. Results: We identified the highest number of black non-Hispanic female breast cancer patients in Michigan and the lowest in Hawaii. The mean (SD), of age at diagnosis (years) was 58.3 (14.43). The mean (SD), of survival time (months) for black non-Hispanic females was 66.8 (30.20). Non-Hispanic blacks had a significantly increased risk of death compared to Black Hispanics (Hazard ratio: 1.96, 95%CI: 1.51-2.54). Compared to other statistical probability models, we found that the exponentiated Weibull model better fits for the survival times. By making use of the Bayesian method predictive inferences for future survival times were obtained. Conclusions: These findings will be of great significance in determining appropriate treatment plans and health-care cost allocation. Furthermore, the same approach should contribute to build future predictive models for any health related diseases.

• Journal of the Ergonomics Society of Korea
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• v.30 no.2
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• pp.349-356
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• 2011

Objective: The purpose of this study was to analyze the risk factors of the musculoskeletal workload of mid-old-age female caregivers by identifying work postures and subjective symptoms. Method: This study was carried out on a total of 206 subjects 206 mid-old-age caregivers(45~65 years old) from November 2009 to April 2010: 206 mid-old-age caregivers (45~65 years old) at the long-term hospital. A questionnaires survey on general factors and subjective symptoms of subjects was conducted. The risk factors of the musculoskeletal workload evaluation method is based on OWAS, RULA, REBA according to occupation properties. Results: The analysis of the rates of the subjective symptoms showed that 78.6% subjects experience low back pain. The analysis of the work type showed that transfer is the highest rate(36.3%) and position change is the second(18.2%). The analysis of the work postures showed that the thrusted back with twisting position over $20^{\circ}$ is highest rate(37.4%), the bended back forward with twisting position is the second(27.5%). Conclusion: This study suggested that the need of preventive education for caregivers and workload improve. It is hoped that subsequent study on the difference of subjective symptoms between educated caregivers and non educated caregivers will be conducted.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.75-80
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• 2005

The present work was undertaken to numerically analyze the defrosting phenomena of windshield glass. In order to analysis the phase change from frost to water on windshield glass by discharging hot air from a defroster nozzle, the flow and the temperature field of the cabin interior, the heat transfer through the windshield glass, and the phase change of frost should be solve simultaneously. In the present work, the flow field was obtained by solving 3-D incompressible Navier-Stokes equations, and the temperature field was computed from the incompressible energy equation. The phase change process was solved by the enthalpy method. For the code validation, the temperature and the phase change of the driven cavity were calculated. The calculation showed a good agreement with other numerical results. Then, the present code was applied to the defrosting problem of a real automobile, and a good agreement with the experimental data was also obtained.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.349-352
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• 2015

This paper estimates electrical fire damage cost-effect to analyze electrical safety efficiency by applying a cost-benefit analysis method for analyzing the efficiency of a business public interest. Electrical fire loss statistics data was presented as direct costs and casualties, including deaths due to an electrical fire, this paper adds overhead "Incidental Cost of Accidents to the Employer" by W. H. Heinrich was applied to estimate the cost of economic loss. Also wounded, including the loss of human deaths by referring to the car accident insurance claims costs and human development estimated the losses caused by an electrical fire. And to perform a cost-benefit analysis of the electrical safety as a result of future work. In this paper, the economic effect of the electric field of safety and public interest work to systematically presented.