• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.38
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• pp.69-76
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• 1996

The Special safety systems are incorporated into the plant design to limit radioactive releases to the public in the event of accident. Wolsung 2 is better builted than Wolsung 1 by 84 design changes for new approval requirements, codes & standards changes and manufacturing changes etc. This paper analysed and discussed the design change items for nuclear reactor safety system and needs development of design engineering for digital protection system.

• Structural Engineering and Mechanics
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• v.60 no.6
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• pp.1079-1092
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• 2016

In this paper, an electromechanical integrated harmonic piezodrive system is proposed. The operating principle of the drive system is introduced. The equation of the relationship between the displacements of the flexible ring and the rotating angle of the rotor is deduced. Using the equation, the displacements of the flexible ring for the drive system and their changes along with the system parameters are investigated. The results show that the displacements of the flexible ring changes periodically along with the rotation of the vibrator; there are abrupt changes in the displacements of the flexible ring at some points where there are abrupt changes in the number of the mesh teeth pair; the length of the flexible ring, the excitation voltage, and the speed ratio have obvious effects on the displacements of the flexible ring. The results are useful for the design of the drive system. ;

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.5
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• pp.29-40
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• 2018

Even if a small amount of arsenic (As) is entering to small agricultural reservoir from upper streams, small agricultural reservoir becomes sensitive to changes in arsenic concentration depending on the water level in case of accumulation continuously because of its scale. If we want to manage arsenic concentration in small agricultural reservoir, it is very important to understand arsenic changes in agricultural reservoir. In spite of the fact that modeling is the most accurate method for analyzing arsenic concentration changes in small agricultural reservoirs, but, it is difficult to monitor arsenic change everyday. So, if data is prepared for modeling arsenic changes, water quality modeling is more effective than monitoring. Therefore, in this study, arsenic concentration changes was simulated and arsenic concentration change mechanism in small reservoir was analyzed using hydrological and water quality monitoring data and by conducting EFDC (Environment Fluid Dynamics Code)-WASP (Water Quality Analysis Simulation Program) linkage. EFDC-WASP coupling technique was very useful for modeling arsenic changes because EFDC can consider hydrodynamic and WASP can perform arsenic concentration simulation, separately. As a results of this study, during dry season, As concentration was maintained relatively high arsenic concentrations. Therefore, water level control will be needed for managing As concentration of reservoir.

• The Journal of the Acoustical Society of Korea
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• v.24 no.2E
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• pp.71-76
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• 2005

Compared to normal speech, distant-talking speech is characterized by the acoustic effect due to interfering sound and echoes as well as articulatory changes resulting from the speaker's effort to be more intelligible. In this paper, the acoustic features for distant-talking speech due to the articulatory changes will be analyzed and compared with those of the Lombard effect. In order to examine the effect of different distances and articulatory changes, speech recognition experiments were conducted for normal speech as well as distant-talking speech at different distances using HTK. The speech data used in this study consist of 4500 distant-talking utterances and 4500 normal utterances of 90 speakers (56 males and 34 females). Acoustic features selected for the analysis were duration, formants (F1 and F2), fundamental frequency, total energy and energy distribution. The results show that the acoustic-phonetic features for distant-talking speech correspond mostly to those of Lombard speech, in that the main resulting acoustic changes between normal and distant-talking speech are the increase in vowel duration, the shift in first and second formant, the increase in fundamental frequency, the increase in total energy and the shift in energy from low frequency band to middle or high bands.

• Journal of Construction Engineering and Project Management
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• v.2 no.3
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• pp.8-16
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• 2012

After the 2008 global financial crisis, the construction environment in South Korea continued change in the construction environment. Construction orders in 2011 have shown a downward trend compared with the previous year. Along with these changes in the construction market, the professional capabilities of construction project managers that are perceived as important also changed after the global financial crisis. Accordingly, this study was conducted to identify the major business capabilities of the current construction project managers and to determine which of these capabilities have undergone changes in terms of the importance accorded to them after the global financial crisis, and ultimately, to derive the construction project manager capability areas that need to be strengthened according to the changes in the construction environment. The capabilities of construction project managers were surveyed at two different time points: in 2007 and in 2010. The results show that the year 2010, after the global financial crisis, an increase in the perceived important capabilities of construction project managers compared with 2007. This results the impact of the changes in the construction environment on the importance of construction project managers. This study derived the ramifications of the early identification of systems and prospects according to the changes in the construction circumstances on more efficient onsite and human resources management, by considering the appropriate capabilities of the construction project managers.

• Journal of Biomedical Engineering Research
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• v.26 no.6
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• pp.383-391
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• 2005

Age-related White Matter Changes (WMC) on Magnetic Resonance Imaging (MRI) are known to appear frequently in Multiple sclerosis (MS) and Alzheimer's disease and to be related to cognitive impairment. The characterization of these WMC is very important to the study of psychology and aging. These changes consist of periventricular and subcortical types, however it is difficult to detect and segment WMC using only intensity-based methods, because their intensity, level IS similar to th~t of the gray matter (GM). In this paper, we propose a new method of segmenting periventricular WMC using K-means clustering and morphological features.

• Geomechanics and Engineering
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• v.30 no.5
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• pp.461-469
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• 2022

One of the most important factors that should be considered for using any ground improvement technique is the stability of stabilized soil and the durability of the provided solution for getting the required engineering properties. Generally, most of the earth structures that are constructed on clayey soils are exposing movements due to the long periods of drying or wetting cycles. Over time, environmental changes may result in swells or settlements for these structures. In order to mitigate this problem, this research has been performed on mixtures of high plasticity clay with traditional additives such as lime, cement and non-traditional additives such as polypropylene fiber. The purpose of the research is to assess the most appropriate ground improvement technique by using commercially available additives for resisting the developed desiccation cracks during the drying process and resisting the volume changes that may result during wet/dry cycles as an attempt to simulate the changes of environmental conditions. The results show that the fiber-reinforced samples have the lowest volumetric deformation in comparision with cement and lime stabilized samples, and the optimum fiber content is identified as 0.38%. In addition, the desiccation cracks were not visible on the samples' surface for both unreinforced and chemically stabilized samples. Regarding cracks resistance resulting from the desiccation process, it is observed, that the resistance is connected with the fiber content and increases with the increase of the fiber inclusion, and the optimum content is between 1% and 1.5%.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.246-249
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• 2003

we classified major changes into changes based on design deficiency, changes based on the different conditions between job site and contract documents, and changes based on the Owner's need. Then we compare and analyzed applicable regulations for supervision and work performance status at the site, and elicit problems of supervision performance based on mutual contradiction in regulations, bringing up a similar example. Based on the above, we brought up a way of improvement for the elicited problem, comparing and analyzing the laws/contract provisions/instructions related with the changes and the work performance at the jobsite, and verified through interviews with professionals of various fields for the improvement. Finally this study could elicit a way of improvement in the supervision work in conjunction with changes in civil works.

• Archives of Plastic Surgery
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• v.46 no.4
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• pp.386-389
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• 2019

The development of breast implant technology continues to evolve over time, but changes in breast shape after implantation have not been fully elucidated. Thus, we performed computerized finite element analysis in order to better understand the trajectory of changes and stress variation after breast implantation. The finite element analysis of changes in breast shape involved two components: a static analysis of the position where the implant is inserted, and a dynamic analysis of the downward pressure applied in the direction of gravity during physical activity. Through this finite element analysis, in terms of extrinsic changes, it was found that the dimensions of the breast implant and the position of the top-point did not directly correspond to the trajectory of changes in the breast after implantation. In addition, in terms of internal changes, static and dynamic analysis showed that implants with a lower top-point led to an increased amount of stress applied to the lower thorax. The maximum stress values were 1.6 to 2 times larger in the dynamic analysis than in the static analysis. This finding has important implications for plastic surgeons who are concerned with long-term changes or side effects, such as bottoming-out, after anatomic implant placement.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.517-523
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• 2016

Unlike household refrigerators, commercial refrigerators are composed of separate indoor and outdoor units. The outdoor unit of most commercial refrigerators is designed to run at a fixed speed, which results in low energy efficiency and loud fan noise. Moreover, it cannot respond flexibly to changing thermal load in the indoor unit. Inverter type outdoor units can address such problems through speed changes based on information obtained from the indoor unit. However, using two units from different manufacturers is often not a viable solution. If condition changes in the indoor unit can be detected without communication between the two units, it is possible to adjust the speed of the outdoor unit. This paper attempts to analyze the signal from the outdoor unit when the condition of the indoor unit changes by varying the thermal load.