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Calibration of Parameters in QUAL2E using the Least-squares Method (최소지승법에 의한 QUAL2E 모델 반응계수 보정)

  • Kim, Kyung-Sub;Yoon, Dong-Gu;Lee, Gi-Young
    • Journal of Korea Water Resources Association
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    • v.37 no.9
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    • pp.719-727
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    • 2004
  • Water quality models can be applied to manage the regional water quality problems and to estimate the target and allowable pollution load in watershed effectively. The optimization of state variables in the given water quality model Is necessary to build up more effective model. The least-squares method is applied to fit field observations in QUAL2E developed by U.S. EPA, which is most widely used one in the world to simulate the stream water quality, and the optimization model with constraints is constructed to estimate the parameters. The objective function of the optimization model is solved by Solver in Microsoft Excel and Monte Carlo simulation is conducted to know the influence of parameter in conventional pollutants. It is found that this technique is easily implemented and rapidly convergent computational procedure to calibrate the parameters after appling this approach in Anyang stream located in Kyonggi province mainly.

Numerical Simulation of Wave Deformation due to a Submerged Structure with a Second-order VOF Method (2차 정확도 VOF기법을 활용한 수중구조물에 의한 파랑변화 예측)

  • Ha, Tae-Min;Cho, Yong-Sik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.1
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    • pp.111-117
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    • 2010
  • A three-dimensional numerical model is employed to investigate wave deformation due to a submerged structure. The three-dimensional numerical model solves the spatially averaged Navier-Stokes equations for two-phase flows. The LES(large-eddy-simulation) approach is adopted to model the turbulence effect by using the Smagorinsky SGS(sub-grid scale) closure model. The two-step projection method is employed in the numerical solutions, aided by the Bi-CGSTAB technique to solve the pressure Poisson equation for the filtered pressure field. The second-order accurate VOF(volume-of-fluid) method is used to track the distorted and broken free surface. A simple linear wave is generated on a constant depth and compared with analytical solutions. The model is then applied to study wave deformation due to a submerged structure and the predicted results are compared with available laboratory measurements.

A Comparison of the Nurses Image according to Clinical Practice Experience of Nursing Students (간호대학생의 임상실습 경험에 따른 간호사 이미지 비교)

  • Kang, Mi-Ran;Jeong, Kyeong-Sook
    • The Journal of the Korea Contents Association
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    • v.17 no.4
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    • pp.342-349
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    • 2017
  • The purpose of this study was to compare nurses' image perceived by two group of nursing students as clinical practice experience and non-clinical practice experience. This study used 400 questionnaires from nursing students in C city to collect data from September 2 to September 9, 2014 The data were analyzed by SPSS/WIN 18.0 program using descriptive statistics, ${\chi}^2$-test, t-test, ANOVA, ANCOVA. According to the result, The nurse image was significantly different between the two groups(F=4750.2, p<.001). Also, the traditional image(F=3631.5, p<.001), social image(F=2872.5, p<.001), professional image(F=4022.9, p<.001), and personal image(F=1812.9, p<.001) of the nurse image sub-domain showed statistically significant differences. Therefore, In order to enhance the image of nurses after clinical practice of nursing college students, continuous efforts will be needed not only in clinical field and nursing college's efforts but also in policy support for nurses' independent work expansion.

Development and Application of a Subject Substitute STEAM Lesson in Elementary School Science Education (초등과학교육에서 차시대체형 STEAM 수업 개발 및 적용)

  • Chae, Dong-Hyun;Moon, Byoung-Chan;Kim, Eun-Jeong
    • Journal of the Korean Society of Earth Science Education
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    • v.7 no.3
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    • pp.327-337
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    • 2014
  • In this research, a subject substitute STEAM program was developed in context of a trend of STEAM education and a new science contents in a 2009 revised curriculum, which can replace the 2009 revised curriculum contents of 'Sound' unit in the third and the fourth grade. The developed program was taught to the 4th graders in a field. After applying the program, how students acknowledge the subject substitute STEAM program was analyzed through questionnaire. The research results were as follows. First, the subject substitute STEAM program of 3 sub programs was developed with centered around 'sound' unit for 4th graders. Second, students made a positive estimation of the STEAM program because of various activities and learning subject related to daily life. Third, they considered difficult term, necessary craft skills in creative design, understanding scientific principle and a lot of necessary time as difficulties of the STEAM program. And they also recognized that making stuff activity and learning aid material like activity sheet, picture and video helped to understand a lesson. Lastly, students had a positive thinking or negative thinking about STEAM program before they learn. But after learning the STEAM program, all of them showed their positive attitude to the STEAM program.

A Study on Public Property of the Regional Museum Design- Focused on the 21st Century Museum of Contemporary Art, Kanazawa, Ishikawaken in Japan - (지역 미술관디자인의 공공성에 관한 연구 - 일본 석천현 금택 21C 현대미술관을 대상으로 -)

  • Son Kwang-Ho;Kim Kang-Sub
    • Korean Institute of Interior Design Journal
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    • v.14 no.6 s.53
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    • pp.177-184
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    • 2005
  • The 21st Century Museum of Contemporary Art, Kanazawa as a regional public culture facility is the place where it is possible to think over the roles and meanings of a museum. The urn of this research is to provide information for exploring a desirable direction of the design of a regional museum by analyzing the architectural meanings and public property of the 21st Century Museum of Contemporary Art, Kanazawa. In addition, we arranged the totes and meanings of a regional museum and the concept of the public property in architecture. We also analyzed the architectural quality and the expression of the public property in this museum, as well as the value and meaning of a museum through field researches. The results of this research are as follows. First, this museum breaks with the existing stereotyped Idea to be a space open to the citizens. It secures a wide public space and provides the convenience of access and every facility for citizens. Second, the floor plan is divided into the interchanging area for citizens and an exhibition area; the outskirts of the inside of the museum are planned to be used free of charge for an interchanging space of citizens as a public-owned space of citizens. Third, the public-owned space of citizens includes a citizen exhibition hall, an art library, a kids studio and rest space, which ate all designed lot everyone to enjoy freely. Last, the exterior shape of the museum is simple but harmonize with the surroundings. It has an unique shape showing the local identity, and its most special properties are the convenience of access, introduction of a free space inside, and security of a huge space for children and citizens.

High Performance Control of IPMSM using SV-PWM Method Based on HAI Controller (HAI 제어기반 SV PWM 방식을 이용하나 IPMSM의 고성능 제어)

  • Choi, Jung-Sik;Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.8
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    • pp.33-40
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    • 2009
  • This paper presents the high performance control of interior permanent magnet synchronous motor(IPMSM) using space vector(SV) PWM method based on hybrid artificial intelligent(HAI) controller. The HAI controller combines the advantages between adaptive fuzzy control and neural network The SV PWM method is applied to a speed control system of motor in the industry field until now and is feasible to improve harmonic rate of output current, switching frequency and response characteristics. This HAI controller is used instead of conventional PI controller in order to solve problems happening when calculating a reference voltage. The HAI controller improves speed performance by hybrid combination of reference model-based adaptive mechanism method, fuzzy control and neural network. This paper analyzes response characteristics of parameter variation, steady-state and transient-state using proposed HAI controller and this controller compares with conventional fuzzy neural network(FNN) and PI controller. Also, this paper proves validity of HAI controller.

Long-term Outlook and Implications of the Marine Biotechnology Market in Korea and Abroad (국내외 해양생명공학 산업시장의 장기예측 및 함의)

  • Jang, Duckhee;Kang, Gilmo;Chae, Gi-Young;Kim, Soo-Ji;Jo, Min-Ju;Cha, Jeong-Mi;Ham, Hyun-Kyung
    • Ocean and Polar Research
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    • v.35 no.2
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    • pp.93-105
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    • 2013
  • The marine biotechnology industry is very significant as compared to other industries as one of the driving forces for economic growth in the next generation in Korea. However, the marine biotechnology market has been considered as a component of the biotechnology industry market which made difficult for creating separate research areas in relation to the scope of the relevant industry market as well as making it difficult to establish its own R&D policy strategies. Accordingly, this study was executed to estimate the future long-term market value of the marine biotechnology within the limit of industrial field and to verify the importance of national R&D investment in marine biotechnology on the basis of estimations within the industrial perspective. To this end, we classified the marine biotechnology industry into the four sub-sectors and estimated the domestic and global industrial market in 2010 and 2024. According to the results, the domestic and global market of the marine biotechnology industry will see a remarkable growth by 2024. In particular, the bio-energy, pharmaceutical and functional foods industry markets will achieve astonishing advances. On the basis of the analysis results, Korea has to establish more progressive and aggressive R&D investment strategies to strengthen national competitiveness through the marine biotechnology industry.

Weighted Integral Method for an Estimation of Displacement COV of Laminated Composite Plates (복합적층판의 변위 변동계수 산정을 위한 가중적분법)

  • Noh, Hyuk-Chun
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.1 no.2
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    • pp.29-35
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    • 2010
  • In addition to the Young's modulus, the Poisson's ratio is also at the center of attention in the field stochastic finite element analysis since the parameters play an important role in determining structural behavior. Accordingly, the sole effect of this parameter on the response variability is of importance from the perspective of estimation of uncertain response. To this end, a formulation to determine the response variability in laminate composite plates due to the spatial randomness of Poisson's ratio is suggested. The independent contributions of random Poisson's ratiocan be captured in terms of sub-matrices which include the effect of the random parameter in the same order, which can be attained by using the Taylor's series expansion about the mean of the parameter. In order to validate the adequacy of the proposed formulation, several example analyses are performed, and then the results are compared with Monte Carlo simulation (MCS). A good agreement between the suggested scheme and MCS is observed showing the adequacy of the scheme.

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A Basic Study of Hexapod Walking Robot (6족 보행로봇에 관한 기초연구)

  • Kang, D.H.;Min, Y.B.;Iida, M.;Umeda, M.
    • Journal of Biosystems Engineering
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    • v.32 no.5
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    • pp.339-347
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    • 2007
  • A hexapod walking robot had been developed for gathering information in the field. The developed robot was $260{\times}260{\times}130$ ($W{\times}L{\times}H$, mm) in size and 14.7 N in weight. The legs had nineteen degrees of freedom. A leg has three rotational joints actuated by small servomotors. Two servomotors placed at ankle and knee played the roles of vertical joint for up and down motions of the leg and the other one placed at coxa played the role of horizontal joint for forward and backward motions. In addition, a servomotor placed at thorax between the front legs and the middle legs played the role of vertical joint for pumping the two front legs to climb stair or inclination. Walking motion of the robot was executed by tripod gait. The robot was controlled by manual remote-controller communicated by an infrared ray. Two controllers were equipped to control the walking of the robot. The sub-controller using PIC microcomputer (Microchips, PIC16F84A) received the 16 bit command signal from the manual remote controller, decoded it to 8bit and transmitted it to the main microcomputer (RENESAS, SH2/7045), which controlled the 19 servomotors using the PWM command signals. Walking speeds were controlled by adjusting the period of command cycle and the stride. Forward walking speed were within 100 cm/min to 300 cm/min. However, experimental walking speed had the error of 4-40 cm/min to compare with the theoretical one, because of slippage of the leg and the circular arc motion of servomotor of coxa.

Analyzing the Disaster Management Service in the Perspective of Disaster Victims as a Demander: An Approach Based on Grounded Theory (재난관리서비스에 대한 수요자의 반응분석: 근거이론적 접근)

  • Yoo, Hyun-Jung;Lee, Jae-Eun
    • The Journal of the Korea Contents Association
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    • v.9 no.5
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    • pp.265-276
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    • 2009
  • Many disaster management actors participate in the disaster sites and they do their best for the best result in their given position. They recover the disaster-stricken area, endeavor to prevent the disaster's relapse, and to rescue and protect the disaster victims. Ultimately, the purpose of their role and effort is to support a physical aid as well as material aid for that disaster victims can return their living condition to the original one before the disaster. However, the disaster management services have been provided in the supplier's view till now. Subsequently, despite significant efforts, providers have failed to comprehend what would be the victim's demand and how to reflect that in the disaster management service. In this paper, we approached and analyzed the recent disaster management service in the way of grounded theory, and endeavored to find the solution which disaster victims preferred. As a result of analysis, we found 184 concepts, 28 sub-categories, and 9 categories which could explain the victims' desired solution. We found that "an imperfect restoration which causes disaster" and "pain of the disaster field" would be main categories among them.