• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.5
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• pp.377-384
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• 2002

For economic evaluation of cooling plant equipments, it is necessary to simplify energy Prediction method, which should includes efficiency corrected by part-load ratio. This study proposed simplified method with regression equations of time-average partial loads and refrigerator capacity. DOE-2 Program was used to carry out a parametric study of twelve design variables. Five input variables were considered to be significant and were used in the regression equations. To test accuracy of simplified method, calculated results were compared with DOE-2 simulated results. Test result showes a good agreement with the simulation result with an error of 5.9∼7.6%. It is expected that this method can be used as an easy prediction tool for comparing energy use of different cooling plants during the early design stage.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2271-2273
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• 1999

The manufacturing technology of XLPE power cable ( e.g. gas curing, triple common extrusion, clean room, super-clean compound, etc.) had been developed in 1960's and the design parameter of insulation thickness for EHV XLPE power cable at present was determined in 1960's. But, the quality of XLPE power cable has been improved up to now. The re-evaluation of design parameter for insulation thickness reductions is required and so we performed weibull plotting test using model cable. This paper describes the evaluation details of the insulation characteristics according to weibull plotting test.

• Journal of Satellite, Information and Communications
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• v.2 no.1
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• pp.41-47
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• 2007

Software GNSS digitized IF signal simulator is being developed by ETRI as a part of development of software-based GNSS Test & evaluation Facility which will provide test and evaluation environment for various software level application and navigation algorithm in GNSS. Software GNSS IF signal simulator will provide digitized GNSS signal including GPS and Galileo. The requirement analysis and conceptual design for the Software GNSS IF signal simulator is presented in this paper.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.24 no.2
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• pp.118-127
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• 2017

Purpose: The purpose of this study was to identify effects of self-evaluation using smartphone recording on competency in nursing skills, satisfaction and learning motivations in nursing students'. The setting was the open laboratory hours. Methods: A quasi-experimental pre/post-test design was conducted in September 2015. The participants were 82 sophomore nursing students from one University. The experimental group did self-evaluation by watching recorded video clips of their performance. The control group did not have any self-evaluation. The primary outcomes were scores from the foley catheterization checklist, scores from a student satisfaction tool, and scores from a learning motivation tool. Data were analyzed using ${\chi}^2$ test, Fisher's exact test, independent t-test, and paired t-test. Results: There was a significant higher mean score in levels of satisfaction by students in the experimental group compared to the control group (t=2.26, p=.027). In addition, improvement in communication skills by the experimental group was significantly higher than improvement in the control group (t=3.96, p<.001). Conclusion: Findings show that self-evaluation using smartphone recordings has positive effects on increasing both communication skills and satisfaction with practice during open laboratory hours. These results indicate that, self-evaluation using smartphone recording is useful as a supplement to traditional open laboratory education.

• Journal of the Korean Society of Safety
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• v.30 no.1
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• pp.52-59
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• 2015

The aim of the paper is to introduce the statistical definition of the specified compressive strength of the concrete to be used for safety evaluation of the existing structure in domestic practice and to present the practical method to obtain the specified strength by utilizing the non-destructive test data as well as the limited number of core test data. The statistical definition of the specified compressive strength of concrete in the design codes is reviewed and the consistent formulations to statistically estimate the specified strength for assessment are described. In order to prevent estimating an unrealistically small value of the specified strength due to limited number of data, it is proposed that the information from the non-destructive test data is combined to that of the minimum core test data. The the sample mean, standard deviation and total number of concrete test are obtained from combined test data. The proposed procedures are applied to an example test data composed of the artificial numerical values and the actual evaluation data collected from the bridge assessment reports. The calculation results show that the proposed statistical estimation procedures yield reasonable values of the specified strength for assessment by applying the non-destructive test data in addition to the limited number of core test data.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.7 s.184
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• pp.130-137
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• 2006

TFT-LCD(Thin Film Transistor Liquid Crystal Display) module is representative commercial product of FPD(Flat Panel Display). Thickness of TFT-LCD module is very thin. It is adopted for major display unit for IT devices such as Cellular Phone, Camcorder, Digital camera and etc. Due to the harsh user environment of mobile IT devices, it requires complicated structure and tight assembly. And user requirements for the mechanical functionalities of TFT-LCD module become more strict. However, TFT-LCD module is normally weak to high level transient mechanical shock. Since it uses thin crystallized panel. Therefore, anti-shock performance is classified as one of the most important design specifications. Traditionally, the product reliability against mechanical shock is confirmed by empirical method in the design-prototype-drop/impact test-redesign paradigm. The method is time-consuming and expensive process. It lacks scientific insight and quantitative evaluation. In this article, a systematic design evaluation of TFT-LCD module for mobile IT devices is presented with combinations of FEA and testing to support the optimal shock proof display design procedure.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.162-169
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• 2009

This paper describes a study on dynamic characteristics analysis and dynamic compliance evaluation of a 5-axis multi-tasking machine tool of ram-head type. Structural dynamics analysis and evaluation are necessary to machine tool design and development to secure good machine tool performance against tough and harsh machining conditions. In this study, natural frequencies and corresponding vibration modes of the machine tool structure were analyzed by using both F.E.M. modal analysis and impulse hammer test. Furthermore, dynamic compliance of the machine tool was analyzed by using F.E.M. and also measured by using a hydraulic exciter test. Both the theoretical analysis and experimental test results showed good agreement with each other.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.8
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• pp.1052-1063
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• 1998

The performance database of small-sized centrifugal compressors is needed for the design of high performance machines and also for the verification of design tools and analysis software. An impeller is designed, manufactured and tested. The effects of several parameters on the evaluation of performance are investigated and the performance test of parallel diffuser is also carried out. The proper estimation of static pressure, total temperature and blockage at the impeller exit is important for performance evaluation. 4 method in cooperation with 3-D calculation is suggested. The measured performances are in a good agreement with the predicted results. However, there are some discrepancies in efficiency.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.446-449
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• 2002

Recently, advanced manufacturing system with high speed and intelligent have been developed for the betterment of machining ability. In this case, reliability prediction work with motion characteristic evaluation of sliding cover has also important roll from design procedure to manufacturing and assembly process. Accordingly in this study, H/W test -bed system for reliability evaluation of sliding cover has been developed to obtain proper reference data for design of new model, and also prevention trouble, quality and life cycle improvement extremely for advanced mother machinary.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.59-62
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• 2008

Scour vulnerability evaluation for shallow foundations was performed to assure bridge safety against scour in the national capital region. The case studies for 26 shallow foundations consisted of site investigation including boring test, bridge scour analysis for the design flood, bearing capacity evaluation of the bridge foundation before and after scour, and comprehensive evaluation of bridge scour vulnerability. Bridge scour vulnerability was determined based on the interdisciplinary concept considering predicted scour depth for the design floods and bearing capacity of foundation as well as dimensions of foundation. Nine of 26 shallow foundations showed the potential future vulnerability to scour with significant decrease in the bearing capacity of foundations due to scour and the remaining 17 were expected to maintain their stability against scour.