• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1149-1149
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• 2006

The leakage characteristic is an important factor in power plant. However, most of power plant have efficiency problem which is occurred leaking between high pressure steam turbine axle and stator. The labyrinth seal which is used between the main turbine axle and stator in the power plant. Because it is able to be non-contact seal and it is minimize clearance to decrease the leakage. But its actual system is too huge to experiment. Therefore, most steam turbine seal performance tests were conducted by air similarity test. This paper described a test facility and program for air similarity test of high pressure steam turbine seal. A test facility has been designed and built to evaluate leakage verification of labyrinth seal. The test facility consist of air compressor, anti-swirl labyrinth seal for 1/3 air similarity model, pressure transducer, air flow measure system, instrumentation and auxiliary system. For evaluation of steam turbine seal performance, the air similarity test of labyrinth seal leakage verification was conducted and we compared experiment data and analysis result.

• The Journal of the Korean dental association
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• v.58 no.1
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• pp.19-26
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• 2019

Purpose: The purpose of this study is to compare the adhesion of Candida albicans according to build angle in 3D printing denture base resin. Methods: The 3D printing was performed by setting the build angle of the disk type specimen designed by CAD program at 0 degree, 30 degrees, 60 degrees, and 90 degrees. Surface roughness was measured using a non-contact 3D microsurface profiler. The specimens were incubated in Candida albicans suspension for 24 hours. The attached Candida albicans were detached by cell scraper. The suspension of detached C. albicans was serially diluted and plated on Trypticase soy broth. After 48 hours of incubation, total colony forming unit was counted. Results: There was no significant difference in surface roughness(Sa) between the test groups, but the interlayer boundary was observed. There was no statistically significant difference in total colony forming units of Candida albicans between the test groups. Conclusion: There was no difference in the average surface roughness and adhesion of Candida albicans between the specimens. It is considered that the setting of the build angle should be set considering the accuracy or strength rather than the roughness of the surface.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.573-586
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• 2021

As the proportion of non-contact work is increasing in the situation of COVID-19 pandemic, the collaboration program market is growing rapidly. As the size of the market grows, vulnerabilities in collaborative programs are constantly being disclosed which increases interest in the security of collaborative tools. In this paper, we introduce the results of vulnerability analysis on Electron-based collaboration programs, noting that a number of collaboration programs are based on the Electron framework, and propose countermeasures to enhance the security of Electron-based applications.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.3
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• pp.191-210
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• 2023

The purpose of this study is to draw implications through domestic and international best case studies of library programs, and to suggest ways to improve a public library reading programs through analysis based on the 3rd Reading Culture Promotion Basic Plan in line with the changing role of future libraries. there is To this end, first, prior studies were analyzed from various angles to derive clustering standards for library programs. Based on this, programs of various domestic and foreign libraries were analyzed based on clustering criteria. And based on the clustering criteria of library programs and the 13 key tasks under the 4 strategies of the 3rd Reading Culture Promotion Basic Plan, the status of a specific public library reading programs was analyzed. Through this, in consideration of the demand of users in the era of the 4th Industrial Revolution, participatory reading promotion programs are expanded, and in response to the post-COVID-19 era, beyond face-to-face library services, non-face-to-face and non-contact library services are also considered. A development plan was presented. It is expected that this analysis and application attempt will ultimately go beyond the unit library and contribute to improving the public library service in Korea into a library program closely related to the lives of users.

• Korean Journal of Oriental Medicine
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• v.16 no.3
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• pp.67-75
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• 2010

Objectives : In order to study the standardization of Qi-gong, and the important spread of education in Qi-gong, we investigated to the cognition of Qi-gong. Method : The descriptive investigation was accomplished to examine the level about the standardization of Qi-gong and the propensity with the Qi-gong training specialist, Qi-gong experience people and non-experience people on a national scale. The data of 572 question papers (140 specialists, 132 Qi-gong experience people, 300 non experience people) were analyzed. The period of the data collection was from Jun, 1, 2009 to Jun, 30, 2009. Result : The motives of Qi-gong participation were Qi-gong training and the individual health. The merit of Qi-gong was beneficial to health. The difficulties of Qi-gong training were the serial motion and doing training alone. And in order to popularize Qi-gong, the motion must simple and the spread of Qi-gong need. The reason of non-participation was the deficiency of the contact opportunity and the reason of participation was beneficial to health. In the future, the national policy for the activation of Qi-gong was the spread of the national exercise through the standardization of Qi-gong. Qi-gong was used in the side of the prevention and the principle of Qi-gong need the modern reinterpretation. And the effect of Qi-gong was more effective in musculoskeletal disease and the valuable part of Qi-gong was the health-longevity. Conclusion : With this, in order to develop the value of Qi-gong, the national support policy will be necessary. And the standardization of Qi-gong motion and program, the development of easy exercise, the educational prevalance, and publicity campaign will be necessary.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.310-315
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• 2007

The axial-flow type blood pump(XVAD) which has been developed in our group consists of mechanical parts (an impeller, a diffuser and a flow straightener) and electrical parts (a motor and a magnetic bearing). The magnetic bearing system fully levitates the impeller to remove mechanical coupling with other parts of the pump with constant gap, which needs non-contact type gap sensing. Conventional gap sensors are too large to be adopted to the implantable axial -flow type blood pump. Thus, in this paper, the compact eddy current type gap sensor system proper for the implantable axial-flow type blood pump was developed and its performance was evaluated in vitro. The developed eddy current type gap sensor system is a transformer type and has a differential probe. Sensor coil(probe) has small dimensions(6 mm diameter, 2 mm thickness) and its optimal inductance was determined as 0.068 mH for the measurement range of $0\sim3mm$. It could be manufactured with 130 turns of the 0.04 mm diameter copper coil. The characteristics of the developed eddy current type gap sensor system was evaluated by in vitro experiment. At experiment, it showed satis(actory performance to apply to the magnetic bearing system of the XVAD. It could measure the gap up to 3mm, but the linearity was decreased at the range of $1.8\sim3.0mm$. Moreover, it showed no difference in different media such as the water and the blood at the temperature range of $35\sim40^{\circ}C$.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.2
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• pp.127-133
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• 2011

A LabVIEW program has been developed together with simple infrared thermography(IRT) system to control the lock-in conditions of the system efficiently. The IR imaging software was designed to operate both of infrared camera and halogen lamp by synchronizing them with periodic sine signal based on thyristor(SCR) circuits. LabVIEW software was programmed to provide users with screen-menu functions by which it can change the period and energy of heat source, operate the camera to acquire image, and monitor the state of the system on the computer screen. In experiment, lock-in IR image for a specimen with artificial hole defects was obtained by the developed IRT system and compared with optical image.

• Ocean and Polar Research
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• v.36 no.4
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• pp.495-503
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• 2014

This paper focuses on the dynamic responses of a tracked vehicle crawling on extremely cohesive soft soil, each side of which is composed of two parallel tracks. The tracked vehicle consisted of 2 bodies. One body is the tracked vehicle body, which is assumed to be a rigid body with 6 DOFs. The other body is the buoy body. The two bodies are connected by a revolute joint. In order to evaluate the travelling performance of a 7 DOFs vehicle, a dynamic analysis program for the tracked vehicle was developed using Newmark's method and the incremental-iterative method. The effects of road wheels on the track and soil are not taken into account. A terra-mechanics model of extremely cohesive soft soil is implemented in form of relationships: normal pressure to sinkage, shear resistance to shear displacement, and dynamic sinkage to shear displacement. Pressure-sinkage relationship and shear displacement-stress relationship should represent the non-linear characteristics of extremely soft soil. Especially, since the shear resistance of soft soil is very sensitive to shear displacement, spatial distribution of shear displacement occurring at the contact area of the tracks should be calculated precisely. The proposed program is developed in FORTRAN.

• Journal of Biomedical Engineering Research
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• v.43 no.6
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• pp.424-433
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• 2022

As the proportion of non-contact telemedicine increases and the number of electrocardiogram (ECG) data measured using portable ECG monitors increases, the demand for automatic algorithms that can precisely analyze vast amounts of ECG is increasing. Since the P, QRS, and T waves of the ECG have different shapes depending on the location of electrodes or individual characteristics and often have similar frequency components or amplitudes, it is difficult to distinguish P, QRS and T waves and measure each parameter. In order to measure the widths, intervals and areas of P, QRS, and T waves, a new algorithm that recognizes the start and end points of each wave and automatically measures the time differences and amplitudes between each point is required. In this study, the start and end points of the P, QRS, and T waves were measured using six Deep Neural Networks (DNN) that recognize the start and end points of each wave. Then, by synthesizing the results of all DNNs, 12 parameters for ECG characteristics for each heartbeat were obtained. In the ECG waveform of 10 subjects provided by Physionet, 12 parameters were measured for each of 660 heartbeats, and the 12 parameters measured for each heartbeat well represented the characteristics of the ECG, so it was possible to distinguish them from other subjects' parameters. When the ECG data of 10 subjects were combined into one file and analyzed with the suggested algorithm, 10 types of ECG waveform were observed, and two types of ECG waveform were simultaneously observed in 5 subjects, however, it was not observed that one person had more than two types.

• Journal of Korean Library and Information Science Society
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• v.47 no.2
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• pp.99-124
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• 2016

Regardless of area, public libraries should establish its status as the knowledge and information service center, cultural enjoyment and lifelong learning space in close contact with everyday life. To do this, it is necessary to survey the citizen's perception of the public library. In this study, researchers investigated and analyzed the perception of Daegu citizens including the weight and importance of public libraries, library use status and reasons for non-use, reading program participation and reasons for non-participation, and regions that require new library facilities. Based on these results, researchers suggested the measures to strengthen the infrastructure of public library and to increase its use in conjunction with other relevant data, that is, domestic and international researches, related laws, national reading survey, national cultural infrastructure overview, Daegu citizen survey, Daegu city brand perception survey, and the status of public libraries in national and Daegu Metropolitan City.