• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.208-213
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• 2021

There is a lack of studies comparing the internal quality of fruit with its external quality. However, issues of internal quality of fruit such as internal browning are important. We propose a method of classifying normal apples and internally browned apples using a near-infrared (NIR) non-destructive system. Specifically, we found the optimal wavelength and characteristics of the spectra for determining the internal browning of Fuji apples. The NIR spectra of apples were obtained in the wavelength range of 470-1150 nm. A group of normal apples and a group of internally browned apples were identified using principal component analysis (PCA), and a partial least squares regression (PLSR) analysis was performed to develop and evaluate the discriminant model. The PCA analysis revealed a clear difference between the normal and internally browned apples. From the PLSR, the correlation coefficient of the predictive model without pretreatment was determined to be 0.902 with an RMSE value of 0.157. The correlation coefficient of the predictive model with pretreatment was 0.906 with an RMSE value of 0.154. The results show that this model is suitable for classifying normal and internally browned apples and that it can be applied for the sorting and evaluation of agricultural products for internal and external defects.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.10 no.1
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• pp.75-81
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• 2014

A simulation of eddy current testing has been utilized for predicting the signal characteristics to the various defects and developing the probes. Especially, CIVA which is a simulation tool dedicated to nondestructive testing has a good accuracy and speed, and provides a three-dimensional graphical user interface for improved visualization and familiar data displays consistent with NDE technique. Although internal validations have been performed by the CIVA software development specialists, an independent validation study is necessary for the accuracy assessment of the software prior to practical use. For this purpose, in this study, eddy current testing signals of ASME FBH calibration standard tube for bobbin probe were simulated using CIVA and the results were compared to the experimental inspected signals based on the relationship between each flaw signal in terms of amplitude and phase, and the shape of the Lissajous curve. And then we verified the accuracy of the simulated signals and the possible range for simulation. Overall, there is a good qualitative agreement between the CIVA simulated and experimental results in the absolute and differential modes at the two inspection frequencies.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.6
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• pp.595-601
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• 2010

Desktop virtualization technology running on the local computing system in the process of resource depletion or degradation, such as upgrading the system to solve problems and manage critical information and systems must be protected. In addition, a virtualized environment by constructing a convenient stand-virtualized infrastructure and user space, and security from external attack or internal flaw or a problem, even if the service fails to respond quickly and should help to recover. In this paper, a comprehensive virtualization technology based on the client's desktop virtualization technology elements needed to find a local computing environment more comfortable and stable in the proposed new virtualization technologies.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1753-1761
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• 2014

Due to the inherent inhomogeneous and anisotropy nature of the composite materials, the detection of internal defects in these materials with non-destructive techniques is an important requirement both for quality checks during the production phase and in service inspection during maintenance operations. The estimation of the time-of-arrival (TOA) and/or time-of-flight (TOF) of the ultrasonic echoes is essential in ultrasonic non-destructive testing (NDT). In this paper, we used split-spectrum processing (SSP) combined with matching pursuit signal decomposition (MPSD) to develop a dedicated ultrasonic detection system. SSP algorithm is used for Signal-to-Noise Ratio (SNR) enhancement, and the MPSD algorithm is used to decompose backscattered signals into a linear expansion of chirplet echoes and estimate the chirplet parameters. Therefore, the combination of SSP and MPSD (SSP-MPSD) presents a powerful technique for ultrasonic NDT. The SSP algorithm is achieved by using Gaussian band pass filters. Then, MPSD algorithm uses the Maximum Likelihood Estimation. The good performance of the proposed method is experimentally verified using ultrasonic traces acquired from three specimens of carbon fibre reinforced polymer multi-layered composite materials (CFRP).

• Journal of the Korean Society for Precision Engineering
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• v.29 no.1
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• pp.48-55
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• 2012

Pressure vessels in vehicle industries, power plants, and chemical industries are often affected by flaw and defect generated inside the pressure vessels due to production processes or being used. It is very important to detect such internal defects of pressure vessel because they sometimes bring out serious problems. In this paper, an optical defect detection method using digital shearography is used. This method has advantages that the inspection can be performed at a real time measurement and is less sensitive to environmental noise. Shearography is a laser-based technique for full-field, non-contacting measurement of surface deformation (displacement or strain). The ultimate goal of this paper is to detect flaws in pressure vessels and to measure the lengths of the flaws by using unwrapping, phase images which are only obtained by Phase map. Through this method, we could decrease post-processing (next processing). Real length of a pixel can be calculated by comparing minimum and maximum unwrapping images with shearing angle. Through measuring several specimen defects which have different lengths and depths of defect, it can be possible to interpret quantitatively by calculating gray level.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.4
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• pp.304-312
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• 1998

In order to assure the reliability and integrity of structures such as bridges, Power and petrochemical plants, nondestructive evaluation techniques are recently playing more important roles. Among the various kinds of nondestructive evaluation techniques, ultrasonic technique is one of the most widely used methods for nondestructive inspection of internal defects in structures. For the reliable quantitative evaluation of internal defects from the experimental ultrasonic signals, a numerical analysis of ultrasonic scattering field due to a defect distribution is absolutely required. In this paper, the SH-wave scattering by multi-cavity defects using elastodynamic boundary element method is studied. The effects of shape of defects on transmitted and reflected fields are considered. The interaction of multi-cavity defects in 50-wave scattering is also investigated. Numerical calculation by the boundary element method has been carried out to predict near field solution of scattered fields of ultrasonic SH-wave. The presented results would be useful to improve the sensitivity of flaw defection for inverse analysis and pursue quantitative nondestructive evaluation for inverse problem.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.173-182
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• 2018

Reservoirs, facilities to store water, are being used in several fields for their ability to hold back a large quantity of water for a long time before the water is actually used. However, at the same time, the reservoirs are considered to have a flaw: the longer they store water, the more the quality of water in these reservoirs deteriorates. Further, when the reservoirs are large, they are more likely to have dead-water regions in out-of-the way spots far from either an in-current or an ex-current canal. This study conducted a Computational Fluid Dynamic (CFD) simulation and tried to figure out the internal flow inside each of the reservoirs with different in-current canals built by the multiple hoe screw nozzle method and the drop in-current method. The drop in-current method is more frequently used. According to the analysis of the internal flow inside each reservoir with the different methods applied, we found that the reservoir with the drop in-current canal would have two rotary currents in the lower region of the reservoir and that the velocity of flow would decrease. For a reservoir with the screw nozzle method, a single rotary current occurred, and inside the reservoir, regardless of height, the current turned out to flow in a regular manner.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.364-377
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• 2020

Although it is never easy to create charming characters that people can relate to, well-formed characters have the power to enable the audience to not only empathize but identify with them. Thus, there is a need for us to examine the parts that make up a well-formed character. According to empathy theory, when the character in the play has a human face that is not different from me, I can feel familiarity and human empathy. Rather than perfection without loopholes, I relate to and sympathize with someone who looks similar to me, with many mistakes and some lack. This study aims to examine the attractiveness of characters in narrative dramas in terms of defects and internal growth. To do this, we tried to compare the setting, evaluation, and performance of characters based on the movie worldviews of two famous brands (DC and Marble), which can be compared directly. I looked at it. In conclusion, the work of hero character but human character setting based on internal growth not only has high evaluation and public evaluation, but also high sales, and thus direct and indirect correlation with the public favorability is significant.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.95-99
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• 2015

The IRR(internal rate of return) is often used by investors for the evaluation of engineering projects. Unfortunately, it has serial flaws: (1) multiple real-valued IRRs may arise; (2) complex-valued IRRs may arise; (3) the IRR is, in special cases, incompatible with the net present value (NPV) in accept/reject decisions. The efforts of management scientists and economists in providing a reliable project rate of return have generated over the decades an immense amount of contributions aiming to solve these shortcomings. Especially, multiple internal rate of returns (IRRs) have a fatal flaw when we decide to accep it or not. To solve it, some researchers came up with external rate of returns (ERRs) such as ARR (Average Rate of Return) or MIRR (MIRR, Modified Internal Rate of Return). ARR or MIRR. will also always yield the same decision for a engineering project consistent with the NPV criterion. The ERRs are to modify the procedure for computing the rate of return by making explicit and consistent assumptions about the interest rate at which intermediate receipts from projects may be invested. This reinvestment could be either in other projects or in the outside market. However, when we use traditional ERRs, a volume of capital investment is still unclear. Alternatively, the productive rate of return (PRR) can settle these problems. Generally, a rate of return is a profit on an investment over a period of time, expressed as a proportion of the original investment. The time period is typically the life of a project. The PRR is based on the full life of the engineering project. but has been annualised to project one year. And the PRR uses the effective investment instead of the original investment. This method requires that the cash flow of an engineering project must be separated into 'investment' and 'loss' to calculate the PRR value. In this paper, we proposed a tabulated form for easy calculation of the PRR by modifing the profit and loss statement, and the cash flow statement.

• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.153-158
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• 2005

In order to investigate the short-term performance of polyethylene electrofusion joints, the mechanical tests and stress analysis have been conducted to the artificially defected weld joints. The defects of lack of fusion with a square-type were fabricated with 10, 20, 30, 40, 50, 60$\%$ size of the width of heat-ing wire zone, respectively. In this defect sires range, both tensile and bending test results showed the dependence of defect size to the electrofusion joints performance, but both sustained pressure and crush test results didn't. The numerical stress analysis results including the soil and internal pressures, tensile and bend-ing stresses clearly showed the dependence of fusion defect size. Based on both mechanical test and stress analysis results, the maximum acceptable defect size in polyethylene electrofusion joints is discussed.