• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1279-1287
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• 2009

An increasingly competitive business environment has been concentrated on industries to reduce the operating costs. Industries such as gas, oil, petrochemical, chemical, and electric power have employed for the operation and used for large equipment or structures that require a high capital investment. In order to meet these requirements, the industries are increasingly moving toward saving the experimental verification and computer simulation. Therefore industries to reduce the maintenance costs without compromising the operational safety have been forced on finding for better and more efficient methods to inspect their equipment and structures. In this study, it focused on the development the real-time non-contract monitoring system as an efficient tool for the experimental study of weld defects based on the relationship between the measured voltage and input parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.869-874
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• 2001

In order that precision equipment using high precision industrial operate normally. vibration criteria of expected area that equipment be set up is micrometer level. that method is a trust design for apply to in field, when there attend to quantifiable method. Hence, semi -empirical method that using on the basis of experimental data about undefined information (properities of vibration source, dynamic properities of structure, etc.,) for prediction of vibration response make the use of dynamic structure design of semiconductor ＆ TFT-LCD in the inside and outside country. Like this, for doing an optimal design of dynamic about structure, it is best important to get trust data that apply to semi-empirical method that is method of prediction vibration level. In this paper, on the basis of experimental data which was offered by a manufacturing company Of precisin equipment that plan to set up in semiconductor factory, we predicted vibration response on expected area that equipment be set up.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.816-822
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• 2008

This study presents the design modification for SCR muffler of a commercial vehicle. Its main objective is the reduction of radiated noise at SCR muffler. For this study, the research of five steps were achieved by experimental and CAE analysis. First step is the measurement of radiated noise using impact-acoustic test. Second step is the source identification using experimental modal analysis. The cause of radiated noise source is confirmed by the resonance of end plates at SCR muffler. Third step confirms the possibility of resonance avoidance using SDM analysis applied the mass control. Fourth step is the suggestion of design modification which is the change of mode shape by CAE analysis. Last step is the verification of design modification using SYSNOISE analysis. Finally, the prototype product applied the countermeasure of resonance evasion was manufactured and the reduction of radiated noise at SCR muffler was confirmed by pass-by noise test.

• Computers and Concrete
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• v.21 no.1
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• pp.47-54
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• 2018

Artificial neural network models can be successfully used to simulate the complex behavior of many problems in civil engineering. As compared to conventional computational methods, this popular modeling technique is powerful when the relationship between system parameters is intrinsically nonlinear, or cannot be explicitly identified, as in the case of concrete behavior. In this investigation, an artificial neural network model was developed to assess the residual compressive strength of self-compacted concrete at elevated temperatures ($20-900^{\circ}C$) and various relative humidity conditions (28-99%). A total of 332 experimental datasets, collected from available literature, were used for model calibration and verification. Data used in model development incorporated concrete ingredients, filler and fiber types, and environmental conditions. Based on the feed-forward back propagation algorithm, systematic analyses were performed to improve the accuracy of prediction and determine the most appropriate network topology. Training, testing, and validation results indicated that residual compressive strength of self-compacted concrete, exposed to high temperatures and relative humidity levels, could be estimated precisely with the suggested model. As illustrated by statistical indices, the reliability between experimental and predicted results was excellent. With new ingredients and different environmental conditions, the proposed model is an efficient approach to estimate the residual compressive strength of self-compacted concrete as a substitute for sophisticated laboratory procedures.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.69-75
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• 2015

PURPOSES : The objective of this study is to evaluate the effectiveness of a geogrid reinforced subbase of permeable flexible pavement structures with respect to permanent deformation. METHODS : Experimental trials employing a repeated triaxial load test scheme were conducted for both a geogrid reinforced subbase material and a control specimen to obtain the permanent deformation properties based on the VESYS model. Along with this, a finite element-based numerical analysis was conducted to predict pavement performance with respect to the rutting model incorporated into the analysis. RESULTSAND CONCLUSIONS : The results of the experimental study reveal that the geogrid reinforcement seems to be effective in mitigating permanent deformation of the subbase material. The permanent deformation was mostly achieved in the early stages of loading and then rapidly reached equilibrium as the number of load applications increased. The ultimate permanent deformation due to the geogrid reinforcement was about 1.5 times less than that of the control specimen. Numerical analysis showed that the permeable, flexible pavement structure with the geogrid reinforced subbase also exhibits less development of rutting throughout the service life. This reduction in rutting led to a 20% decrease in thickness of the subbase layer, which might be beneficial to reduce construction costs unless the structural adequacy is not ensured. In the near future, further verification must be conducted, both experimentally and numerically, to support these findings.

• Fire Science and Engineering
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• v.18 no.3
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• pp.9-17
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• 2004

The values of physical properties of the inert gases of Ar, $N_2$, $CO_2$ were calculated by the empirical equations. The regression coefficients were obtained by the experimental data and the resulting calculated values. For the empirical equation with a lower regression coefficient, a new correlation was suggested. At an atmosphere pressure, the empirical equation was confirmed by the experimental values for the viscosity, density, saturated pressure, and surface tension of Ar, $N_2$, $CO_2$. The correlation coefficients of the empirical equations proposed in this work was higher than 0.99.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.1
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• pp.7-13
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• 2015

Unmanned air vehicles (UAVs) are getting popular not only as a private usage for the aerial photograph but military usage for the surveillance, reconnaissance and supply missions. For an UAV to successfully achieve these kind of missions, geolocation (localization) must be implied to track an interested target or fly by reference. In this research, we adopted multi-sensor fusion (MSF) algorithm to increase the accuracy of the geolocation and verified the algorithm using two multicopter UAVs. One UAV is equipped with an optical camera, and another UAV is equipped with an optical camera and a laser range finder. Throughout the experiment, we have obtained measurements about a fixed ground target and estimated the target position by a series of coordinate transformations and sequential Kalman filter. The result showed that the MSF has better performance in estimating target location than the case of using single sensor. Moreover, the experimental result implied that multi-sensor geolocation algorithm is able to have further improvements in localization accuracy and feasibility of other complicated applications such as moving target tracking and multiple target tracking.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.11
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• pp.943-948
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• 2016

In recent times, the requirement of a micro pattern on the surface of products has been increasing, and high precision in the fabrication of the pattern is required. Hence, in this study, dual micro patterns were fabricated on a cylindrical workpiece, and deburring was performed by magnetic abrasive deburring (MAD) process. A prediction model was developed, and the MAD process was optimized using the response surface method. When the predicted values were compared with the experimental results, the average prediction error was found to be approximately 7%. Experimental verification shows fabrication of high accuracy dual micro pattern and reliability of prediction model.

• Journal of the Korean Applied Science and Technology
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• v.24 no.4
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• pp.354-361
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• 2007

The distribution of light in a randomly scattering medium can represent problems found in many area. Particularly, in the clinical application of lasers for Photodynamic therapy(PDT) or in the fluorescence spectroscopy for biological tissue, turbidity plays a very important role. The influences of fluorophor, scatterer, and absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength. The molecular properties have been studied by laser induced fluorescence spectroscopy in scattering medium as tissue. It has been found that the effects of optical properties in scattering media could be investigated by the optical $parameters({\mu}_s$, ${\mu}_a$ ,${\mu}t)$. Experimental and Monte Carlo simulation method for modelling light transport in tissue was applied. The experimental results using a randomly distributed scattering medium were discussed and compared with those obtained through Monte Carlo simulation. It'll be also important in designing the best model for oil chemistry, medicine and application of medical engineering.

• Journal of Korean Academy of Nursing
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• v.43 no.4
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• pp.468-477
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• 2013

Purpose: This study was conducted to develop a simulation-based education program for newborn emergency care based on most needed topics found from the needs assessment. This study consisted of two phases: developing the program and evaluating its effectiveness. Methods: The effectiveness of the program was tested in July, 2012, with 49 junior nursing students from C Nursing College in Seoul, who did not have any clinical experience in newborn care. The experimental group was given a three-hour lecture, three hours of clinical training, and a two-hour simulation program, whereas the control group only had the three-hour lecture. Results: There was significant improvement in knowledge in both groups, but no significant differences according to educational methods. The experiment group was more confident of their care ($4.32{\pm}.29$) than the control group ($3.60{\pm}.29$) with the difference being significant (t=8.85, p<.001), and the experimental group was also more satisfied with the program (${\chi}^2$=4.60, p=.032). Conclusion: As the results indicate 'the neonatal emergency care program' increased learners' knowledge, confidence and satisfaction with the program, it should be integrated into clinical training in pediatric nursing curriculum and in-service programs for nurses. To increase generalization further verification studies with various learner groups are needed.