• Title/Summary/Keyword: Experimental designs

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Hydrogen Brittleness on Welding Part for SDS Bottles (삼중수소 저장용기 이종 접합부의 수소 취성)

  • Kim, Raymund K.I.;Jung, Seok;Kang, Hyungoo;Chang, Minho;Yun, Seihun;Hong, Tae-Whan
    • Journal of Hydrogen and New Energy
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    • v.24 no.2
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    • pp.121-127
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    • 2013
  • Tritium was attracted with high energy source in neutron fusion energy systems. A number of research was performed in tritium storage materials. The Korea was raised storage and delivery systems (SDS) of international thermonuclear experimental reactor (ITER) research. However, bottles of SDS would be important because of stability. The bottles have a welding zone, this zone will be vulnerable to hydrogen embrittlement. This zone have a high thermodynamic energy and heat deterioration. Therefore bottles were studied about hydrogen embrittlement to retain stability. The heat treatment of hydrogen was carried under pressure-composition-temperature (PCT) apparatus because of checking at real time. And then, mechanical properties were evaluated by tensile test and hardness test. In results of this study, hydrogen atmosphere condition is very important by tensile test and kinetics test. The samples were evaluated, that is more weak hydrogen pressure, increasing temperature and time. This results could be useful in SDS bottle designs.

Performance evaluation on Fault Current Controller System for the Applications of Smart Grid

  • Jang, Jae-Young;Lee, Woo-Seung;Lee, Ji-Ho;Hwang, Young-Jin;Jo, Hyun-Chul;Ahn, Min-Cheol;Hur, Kyeon;Ko, Tae-Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.14 no.2
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    • pp.12-15
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    • 2012
  • This paper presents simulation and small-scale experimental tests of a fault current controller. Smart fault controller as proposed and proven conceptually in our previous work is promising technology for the smart power grid where distributed and even stochastic generation sources are prevalent and grid operations are more dynamic. Existing protection schemes simply limiting the fault current to the pre-determined set values may not show best performance and even lead to coordination failures, potentially leading to catastrophic failure. Thus, this paper designs fault current controller with a full bridge thyristor rectifier, embedding a superconducting coil for which the controller is electrically invisible during normal operation because the loss due to the coil is near-zero. When a fault occurs and the resulting current through the superconducting coil exceeds a certain value set intelligently based on the current operating condition of the grid, the magnitude of the fault current is controlled to this desired value by adjusting the firing angles of thyristors such that the overall system integrity is successfully maintained. Detailed time-domain simulations are performed and lab-scale testing circuits are built to demonstrate the desired functionality and efficacy of the proposed fault current controller.

Analysis of Research Studies Published in Journal of Korean Critical Care Nursing : 2008-2013 (중환자간호학회지 2008~2013년 게재 논문 분석)

  • Son, Youn-Jung;Kang, Jiyeon;Song, Hyo-Jeong;Park, Young-Rye;Lee, Yun-Mi;Park, Jin-Hee;Kim, Minju
    • Journal of Korean Critical Care Nursing
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    • v.6 no.2
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    • pp.78-88
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    • 2013
  • Purpose: The purpose of this study was to identify the trends in studies published in Journal of Korean Critical Care Nursing (JKCCN) from 2008 to 2013. Methods: A total of 65 studies published between 2008 to 2013 were reviewed using criteria developed by researchers. Results: Approximately 36% of studies were conducted with patients. Intensive care unit (ICU) was the most popular site as the study setting. Among 59 research papers, 42.4% were approved by institutional review board (IRB). Quantitative studies were 78.6%, while qualitative studies were 4.6%. The research designs for the quantitative studies were survey (52.3%), quasi-experimental (16.9%), and so on. There was no randomized controlled trial. The most frequently used methods to provide nursing intervention was education. In addition, "nurse" and "ICU" were most commonly used keyword. Conclusion: Considering the low rate of IRB approval, more stringent application of research ethics is necessary to improve the quality of JKCCN. In addition, more randomized controlled trials should be encouraged to support evidence-based practice in critical care.

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Recognition of Unconstrained Handwtitten Numerals Based on Modular Design and Pipeline Connection (모듈러 설계 및 파이프라인 연결에 기반한 무제약 필기 숫자의 인식)

  • Oh, Il-Seok;Choi, Soon-Man;Hong, Ki-Cheon;Lee, Jin-Seon
    • Korean Journal of Cognitive Science
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    • v.7 no.1
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    • pp.75-84
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    • 1996
  • In this paper we emphasize the importance of architectural aspects of designing a handwritten numeral recognition program. and describe two architectural design.First, we describe the modular design of a numeral recognition program, and mention its advantages.In this design, a recognizer is composed of 10 binary subrecognizers each of which is responsible for only one class.Rule-based training and neural-based training are presented.Second, we connect two(or more)recognizers serially which we call pipelining connection.The second recognizer may act as verifier for the patterns recognized by the forst recognizer, or as second chance recognizer for the patterns rejected by the first recognizer.Our experimental results obtained till now show the merits of the proposed architectural designs.

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Statistical Optimization of the Growth Factors for Chaetoceros neogracile Using Fractional Factorial Design and Central Composite Design

  • Jeong, Sung-Eun;Park, Jae-Kweon;Kim, Jeong-Dong;Chang, In-Jeong;Hong, Seong-Joo;Kang, Sung-Ho;Lee, Choul-Gyun
    • Journal of Microbiology and Biotechnology
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    • v.18 no.12
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    • pp.1919-1926
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    • 2008
  • Statistical experimental designs; involving (i) a fractional factorial design (FFD) and (ii) a central composite design (CCD) were applied to optimize the culture medium constituents for production of a unique antifreeze protein by the Antartic micro algae Chaetoceros neogracile. The results of the FFD suggested that NaCl, KCl, $MgCl_2$, and ${Na}_{2}{SiO}_{3}$ were significant variables that highly influenced the growth rate and biomass production. The optimum culture medium for the production of an antifreeze protein from C. neogracile was found to be Kalle's artificial seawater, pH of $7.0{\pm}0.5$, consisting of 28.566 g/l of NaCl, 3.887 g/l of $MgCl_2$, 1.787 g/l of $MgSO_4$, 1.308 g/l of $CaSO_4$, 0.832 g/l of ${K_2}{SO_4}$, 0.124 g/l of $CaCO_3$, 0.103 g/l of KBr, 0.0288 g/l of $SrSO_4$, and 0.0282 g/l of ${H_3}{BO_3}$. The antifreeze activity significantly increased after cells were treated with cold shock (at $-5^{\circ}C$) for 14 h. To the best of our knowledge, this is the first report demonstrating an antifreeze-like protein of C. neogracile.

A Study of April Greiman's Work (에이프릴 그레이만의 작품에 관한 연구)

  • 홍석일
    • Archives of design research
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    • v.9
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    • pp.1201-1208
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    • 1994
  • During the 1970s, as Los Angeles-based designer April Greiman made her professional way, her work was popularly labeled "New Wave: The term no longer seems to fit. Today, Greiman refers to her brand of design as "hybrid imagery." For combining photography, drawing, video, computer-generated images and typography in her designs, she creates a crossbreed that blends but is unlike any of its parts. To her credit, Greiman was one of the first designers who saw potential in the "textures" of video and computer-based imagery, and was brave enough to integrate this new visual language into the mainstream design work she was creating. She was also one of the designers to use the Macintosh computer as her primary design tool. Despite her pioneering work, she refuses the label of "experimental" designer. She prefers to say she, is interested in process, in layering images to evoke both a thoughtful and emotional response. thoughtful and emotional response.

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The Effect of Aspect Ratio on the Aerodynamic Characteristics of an Insect-based Flapping Wing (곤충 모방형 플래핑 날개의 공력특성에 관한 가로세로비 효과)

  • Han, Jong-Seob;Chang, Jo-Won;Jeon, Chang-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.8
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    • pp.662-669
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    • 2012
  • The effect of aspect ratio (AR) on the aerodynamic characteristics of a flapping wing was examined to analyze the design parameters of an insect-based MAV. The experimental model constructed with 4-bar linkages was operated in a water tank with the condition of a low Reynolds number. A water-proof micro-force load cell was fabricated and installed at the root of the wing which is made of a plexiglas. The wing shapes were based on the planform of a fruit fly wing. The ARs selected were 1.87, 3.74 and 7.48 and the Reynolds number was fixed at $10^4$. For AR=1.87 and 3.74, distinct lift peaks which indicate unsteady effects such as 'wake-capture' were observed at the moment of the start of the wing-stroke. However, for AR=7.48, no unsteady effects were observed. These phenomena were also observed in the delayed rotation case. The results indicate that a larger AR provides better aerodynamic performance for the insect-based flapping wing which can be applied in MAV designs.

The Effects of Somatosensory Stimulation of the Hands on the Hand Functions and Visuomotor Coordination Function of Children with Developmental Disabilities

  • Kong, Nam Ho;Lee, Jun Cheol;Lee, Han Ki
    • Journal of International Academy of Physical Therapy Research
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    • v.5 no.1
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    • pp.652-660
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    • 2014
  • In the present study, to examine the effects of somatosensory stimulation of the hands on the hand functions and visuomotor coordination of children with developmental disabilities, a total of 24 sessions of experiments were conducted with three children with developmental disabilities for 60 minutes per session, three sessions per week from January 7, 2013 to March 11, 2013. To examine the effects of somatosensory stimulation of the hands on grasping and visuomotor coordination which are sub-areas of PDMS-2, the A-B study design was used which is a single case study method out of single-subject experimental research designs. Somatosensory stimulation of the hands was shown to be effective in improving the hand functions of children with developmental disabilities. Somatosensory stimulation of the hands showed positive effects on the raw scores and standardized scores of grasping and visuomotor coordination in all the three subject children. Visuomotor coordination functions showed higher scores in post-hoc tests in all three children. In particular, ring throws showed high scores at right $90^{\circ}$, right $45^{\circ}$, center, left $45^{\circ}$, and left $90^{\circ}$ among visual directions. In the present study conducted with children with developmental disabilities, ring throws were performed to examine visuomotor coordination. In particular, the numbers of successes of ring throws on the front, left, and right were shown to be high. Therefore, somatosensory stimulation of the hands was effective on the hand functions and visuomotor coordination functions of children with developmental disabilities.

Exploratory Research on the Fidelity Management and the Digitalization of New Product Development Process (신제품 개발과정의 디지털화와 현실반영 정확도 관리에 대한 탐색적 연구)

  • Im, Chae-Seong;Kim, U-Bong
    • Journal of Technology Innovation
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    • v.16 no.2
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    • pp.65-94
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    • 2008
  • There has been rapid diffusion of digital innovation technology(DIT) such as 3 D CAD, CAE, simulation software which enable firms to see the future results of intended product designs through 3 D diagram and simulated results. This technology helps firms to reduce trial and error process by solving later stage problems in earlier stages. The DIT being the technology reflecting the real world, as a tool representing the simplified form of the real world, the degree of reflecting the real world(fidelity) is important in utilizing the DIT. This study is an exploratory research examining the process of reviewing the fidelity of the DITs and developing the complementary process necessary for utilizing the DIT with 'not good enough' fidelity. This study could draw out, from its case study, an exploratory hypothesis about the process of developing the complementary process. In the process, there is an analysis of the corresponding relationship between the actual data and the output data of the DIT, e.g. simulated result. Then the input data or output data are adjusted on the basis of the analysis of the corresponding relationship so that the discrepancy between the actual data and the expected interpretation of the output data, through the adjustment, of the DIT, can be reduced. This process is sometimes accompanied by the process of generating experimental data, which reflect the unique situation of the product development process of a company, to be put to the data base of DIT. The complementary process is the process requiring knowledge sharing and adjustment activities across different divisions. This study draw outs implications for effective management of the fidelity of DIT tools.

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Methodology of Springback Prediction of Automotive Parts Applied 3rd Generation AHSS Using the Progressive Meta Model (프로그레시브 메타모델을 이용한 3세대 초고장력강판 적용 차체 부품의 스프링백 예측 방법론)

  • Yoon, J.I.;Oh, K.H.;Lee, S.R.;Yoo, J.H.;Kim, T.J.
    • Transactions of Materials Processing
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    • v.29 no.5
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    • pp.241-250
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    • 2020
  • In this study, the methodology of the springback prediction of automotive parts applied 3rd generation AHSS was investigated using the response surface model analysis based on a regression model, and the meta model analysis based on a Kriging model. To design the learning data set for constructing the springback prediction models, and the experimental design was conducted at three levels for each processing variable using the definitive screening designs method. The hat-shaped member, which is the basic shape of the member parts, was selected and the springback values were measured for each processing type and processing variable using the finite element analysis. When the nonlinearity of the variables is small during the hat-shaped member forming, the response surface model and the meta model can provide the same processing parameter. However, the accuracy of the springback prediction of the meta model is better than the response surface model. Even in the case of the simple shape parts forming, the springback prediction accuracy of the meta model is better than that of the response surface model, when more variables are considered and the nonlinearity effect of the variables is large. The efficient global optimization algorithm-based Kriging is appropriate in resolving the high computational complexity optimization problems such as developing automotive parts.