• Title, Summary, Keyword: 종결식

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Historical analysis of System of Equations-Focused on Resultant (연립방정식 풀이의 역사발생적 고찰-종결식을 중심으로)

  • Choi, Eun Mi
    • Journal for History of Mathematics
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    • v.26 no.2_3
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    • pp.149-161
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    • 2013
  • The history of finding solutions of linear equations went back to some thousand years ago, and has been steadily developed to solve systems of higher degree polynomials. The method to eliminate variables came into use around the 17th and 18th century. This technique has been extended to the resultant theory that was laid in the 19th century by outstanding mathematicians as Euler, Sylvester, and B$\acute{e}$zout. In this paper we discuss the historical reflection about the development of solving system of polynomials. We add a special emphasis on E. B$\acute{e}$zout who gave the first account on the resultant which is a generalization of discriminant and Gauss elimination method.

The Differential Effects of Cultural Disposition and Need for Cognitive Closure on Framing Effects (문화성향과 종결욕구에 따른 틀효과에서의 차이)

  • Joo, Mijung;Lee, Jaesik
    • Korean Journal of Cognitive Science
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    • v.24 no.2
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    • pp.173-201
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    • 2013
  • This study aimed to investigate the differential effects of individual's cultural disposition (individualism-collectivism or horizontal-vertical thinking) and need for cognitive closure(NFC) on framing effects. For this purpose, the participants were divided into 4 different cultural disposition groups based on Singelis et al.'s[1] INDCOL scale, and 2 different NFC groups based on Lee's[2] NFC Scale, and then asked to respond on 5 decision making scenarios. The results can be summarized as followings. First, participants preferred risk-avoidant option in gain frame, whereas risk-seeking option in loss frame. Second, there are no difference of cultural disposition on framing effects, but high NFC group showed larger framing effects than low NFC group in loss frame. Third, collectivism and vertical thinking in high NFC condition showed larger framing effects than low NFC condition.

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An Analysis of the Relative Importance of Processes in the Closure Phase of Construction Program (건설프로그램 종결단계 업무프로세스의 상대적 중요도 분석)

  • Lee, Woo-Yeon;Lee, Seung-Hoon;Cha, Yongwoon;Hyun, Chang-Taek
    • Korean Journal of Construction Engineering and Management
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    • v.21 no.4
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    • pp.62-71
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    • 2020
  • Various studies on program management have been attempted due to recent changes in the environment of the construction market, and the importance of closure phase in each phase of the construction program is increasing. However, the reality is that the related research is insufficient and the field has been managed in a rule of thumb according to individual capabilities. Therefore, in order to successfully close the construction program and enhance satisfaction of stakeholders in the closure phase of the construction program, the key stakeholders were identified using the Power and Interest Matrix. The relative importance of the closure phase process was analyzed using AHP analysis method. It was also verified through on-site surveys and interviews about the proposed importance of the closure stakeholder and the relative importance of the process. It is expected that this study will increase the satisfaction of stakeholders and contribute to a successful closure if the user puts a lot of resources into the process that has a high priority in the closure phase of the construction program proposed in this study.

Development and Implementation of Algebraic Elimination Algorithm for the Synthesis of 5-SS Spatial Seven-bar Motion Generator (5-SS 공간 7절 운동생성기 합성을 위한 대수적 소거 알고리듬의 개발과 구현)

  • Lee, Tae-Yeong;Sim, Jae-Gyeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1
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    • pp.225-231
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    • 2000
  • Dimensional synthesis of planar and spatial mechanisms mostly requires solution-finding, procedure for a system of polynomial equations. In case the system is nonlinear, numerical techniques like Newton-Raphson are often used. But there are no logical ways for finding all possible solutions in such iterative methods. In this paper, algebraic elimination is used to get all solutions for the synthesis of 5-SS spatial mechanism with seven prescribed positions. The proposed algorithm is more suitable for computer implementation and takes less time than existing one. Two numerical examples are given to demonstrate the implemented algorithm.

Design Method for Asynchronous Circuit (비동기식 회로 설계 기술)

  • Oh, M.H.;Kim, Y.W.;Shin, C.H.;Kim, S.N.
    • Electronics and Telecommunications Trends
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    • v.24 no.6
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    • pp.110-120
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    • 2009
  • 비동기식 회로는 전역 클록이 없이 모듈끼리의 핸드셰이크 프로토콜에 의해 데이터를 동기화하고, 전송하는 회로로 전역 클록에 기반한 동기식 회로에 비해 전역 클록으로 인한 문제점들, 예를 들면, 타이밍 종결 문제, 전력 소모 문제, 다중 클록 도메인 설계 문제 등에서 이점을 갖는다. 최근에는 이 두 가지 회로의 장점을 모아 서로 다른 클록에 기반한 비교적 작은 규모의 동기식 모듈을 기반으로 모듈끼리의 데이터 전송을 비동기식으로 수행하는 GALS 구조도 많이 연구되고 있다. 본 고에서는 이러한 비동기식 회로를 위한 설계 방식을 설명하기 위해 먼저, 비동기식 회로의 특성과 설계 동향, 설계 방식에 영향을 미치는 핸드셰이크 프로토콜 및 지연 모델을 소개한다. 그리고, 크게 세가지의 설계 방식을 간단한 예제를 통해 설명한다.

Application of Non-hydrostatic Free Surface Model for Three-Dimensional Viscous Flows (비정수압 자유수면 모형의 3차원 점성 흐름에의 적용)

  • Choi, Doo-Yong
    • Journal of Korea Water Resources Association
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    • v.45 no.4
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    • pp.349-360
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    • 2012
  • A horizontally curvilinear non-hydrostatic free surface model that was applicable to three-dimensional viscous flows was developed. The proposed model employed a top-layer equation to close kinematic free-surface boundary condition, and an isotropic k-${\varepsilon}$ model to close turbulence viscosity in the Reynolds averaged Navier-Stokes equation. The model solved the governing equations with a fractional step method, which solved intermediate velocities in the advection-diffusion step, and corrects these provisional velocities by accounting for source terms including pressure gradient and gravity acceleration. Numerical applications were implemented to the wind-driven currents in a two-dimensional closed basin, the flow in a steep-sided trench, and the flow in a strongly-curved channel accounting for secondary current by the centrifugal force. Through the numerical simulations, the model showed its capability that were in good agreement with experimental data with respect to free surface elevation, velocity, and turbulence characteristics.

Extraction characteristics of extraction resins containing PC88A (PC88A를 함유한 추출레진의 추출 특성)

  • Park, Kye-Sung;Lee, Jin-Young;Yoon, Ho-Sung;Kim, Chul-Joo;Eom, Hyoung-Choon;Kim, Joon-Soo
    • Proceedings of the Korean Institute of Resources Recycling Conference
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    • pp.168-172
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    • 2005
  • 동일한 추출제가 함유된 3종의 추출레진을 대상으로 중희토류인 Gd의 추출특성을 비교하였다. 실험조건은 $20^{\circ}C$에서 평형 pH, Gd 농도, 추출시간으로 하여 다음과 같은 결과를 얻었다. 추출레진에서 추출시간 5분이내에 $Gd^{3+}$ 이온이 90%이상 추출되며, 추출시간 30분 이후에 변화가 거의 없어 추출반응이 종결된 것으로 판단된다. 평형 pH. 2.2이하에서 분배비는 평형 pH에 대해 선형적으로 감소하였다. Freundlich's 흡착등온식을 도입하여 3종의 추출레진에 대해 적용해 본 결과 결정계수$(R^2)$ 0.95이상으로 나와, Freundlich's 흡착등온식에 부합됨을 알 수 있었다.

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유아 대상 영양교육 프로그램의 개발 및 효과평가

  • 신은경;이연경
    • Proceedings of the KSCN Conference
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    • pp.1054.1-1054
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    • 2003
  • 유아기의 올바른 식습관 형성은 일생동안의 건강상태에 영향을 미치므로 이 시기의 영양교육은 특별히 중요할 뿐 아니라, 보육시설에서도 유아 영양교육의 필요성은 인식하고 있으나 영양교육 프로그램의 개발이 부족한 현실이다. 본 연구에서는 유아 대상 영양교육 매체를 개발하여 2003년 3월부터 8월까지 6개월간 구미시 24개 보육시설을 직접 방문하여 4-6세 810명의 유아들을 대상으로 영양교육을 1회 20-30분씩 5회에 걸쳐 실시하고 그 효과를 평가하였다. 개발한 영양교육 매체로는 동영상 CD-ROM(1), 패널(5), 비디오테이프(1), 포스터(4), 표어(2), 리플릿(2), 그림판(2), 손인형 및 보상용 스티커와 책받침 등이며, 교육 내용은 ‘식사 전에 손을 씻어요’ ‘식품과 친해져요’ ‘골고루 먹어요’ ‘즐겁게 식사해요’ ‘올바른 식습관을 가져요’ 등 5가지로 구성하였다. 영양교육 방법은 도입단계에서는 2~3분 정도의 애니메이션으로 동기유발 시켰으며, 전개단계에서는 흥미를 돋우기 위하여 간단한 동영상으로 교육하고, 종결단계에서는 재미있는 퀴즈를 풀면서 마무리하도록 하였다. 또한 보육시설 원장과 교사를 대상으로 하여 2회에 걸친 영양교육을 실시하였으며, 영양사의 영양교육 후 동일 내용을 교사들이 유아들에게 비디오 테이프를 보여 주면서 반복 학습시켰다. 교육 효과를 평가하기 위해 위생 및 영양지식도 조사지(손위생 2문항, 식품군 3문항, 균형식 2문항, 소화과정 1문항, 올바른 식습관 5문항)를 이용하여 사전 사후검사를 실시하였다. 대상 아동은 평균 신장 108cm, 체중 19kg이었고, 평균 헤마토크리트치는 37%, 헤모글로빈은 12g/㎗, 총 콜레스테롤은 156mg/㎗로 정상범위에 속했으며 여아는 남아보다 체지방량과 총 콜레스테를 농도가 유의하게 높았다(p<0.05). 유아들의 위생 및 영양교육 전후의 지식도를 비교해보면 교육 전에는 총 13문항 중 정답수간 평균 7문제로 정답율이 53.3% 였으나 교육 후 정답수가 평균 11문제로 정답율이 84.6%로 향상되었다. 영양지식도는 교육 전에 비해 교육 후 남아와 여아 모두 유의하게 증가하였다(p<0.05). 따라서 본 연구에서 개발한 영양교육 프로그램은 유아들의 영양지식도를 향상시키는데 효과적임이 밝혀졌다. 그러나 본 연구에서는 유아들의 식품선택에 대한 태도 변화를 측정하지 못한 한계점을 가지므로 앞으로의 연구에서는 더 많은 유아용 동영상 영양교육 매체들이 다양한 주제로 개발되고 지식, 태도, 실천면에서 그 효과가 평가되어지기를 제언한다.

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Development and Evaluation of a Left-Turn Actuated Traffic Signal Control Strategy using Image Detectors (영상검지기를 이용한 좌회전 감응식 신호제어전략 개발)

  • Eun, Ji-Hye;O, Yeong-Tae;Yun, Il-Su;Lee, Cheol-Gi;Kim, Nam-Seon;Han, Ung-Gu
    • Journal of Korean Society of Transportation
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    • v.29 no.2
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    • pp.111-121
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    • 2011
  • This paper discusses a method for optimizing the semi-actuated traffic signal control system by adjusting the initial interval according to the number of vehicles waiting for the green light in the actuated phase. We also present a Left-Turn actuated traffic signal control strategy that examines the vehicular noise in the detection area and determines the phase extension and the gap-out. In order to detect the vehicles in real-time, an image detector's Video Image Tracking technology was adopted. A 'Zone in Zone'method was implemented, and the image detection area is segmented into three zones: 1) Zone1 for verifying a vehicles obligatory presence, 2) Zone2 for counting the standby vehicles, and 3) Zone3 for examining the number of vehicles that have passed. The on-site assessment of the Left Turn Actuated Control is carried out using CORSIM, and the results show that the Control Delay decreased by 23.10%, 15.06%, and 4.34% compared to the delays resulted from pre-timed control, semi-actuated control-1 and semi-actuated control-2 traffic signal control systems respectively. The Queue Time also decreased by 36.24%, 20.10% and the Total Time by 14.36%, 7.02% for the same scenario. Which clearly demonstrates the operational efficiency. A sensitivity analysis reveals that the improvement from the propose traffic control strategy tends to increase as the through traffic volume reaches a saturated condition and the left-turn traffic volume decreases.

Enhancement of ${\beta}$-1,3-Glucan Functionality by Batch and Semi-continuous Typed Specific Carboxylation (회분식 및 반연속식 특이적 카르복실화 반응에 의한 ${\beta}$-1,3-glucan의 기능성 향상)

  • Jeong, Suk-Yun;Kim, Sang-Woo;Lee, Yong-Hwan;Lee, Jae-Hwan;Chang, Pahn-Shick
    • Korean Journal of Food Science and Technology
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    • v.40 no.2
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    • pp.146-151
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    • 2008
  • In this study, batch or semi-continuous reactions, introducing site-specific carboxylic acids in ${\beta}$-1,3-glucan structures, were performed to increase water solubility and gel forming ability, using TEMPO/hypobromite with or without NaBr as catalysts. Regio-selective carboxylic acid formations were determined with infrared (IR) and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopic analyses. The regio-selective reactions with and without NaBr gave oxidation yields of 92.5 and 85.6%, respectively, in the batch type, and yields of 93.9 and 86.4%, respectively, in the semi-continuous type. The reaction times in the batch and semi-continuous reactions without NaBr were delayed by 100 and 150%, respectively, as compared to those with NaBr. A combination of IR and $^{13}C$ NMR analyses were used to confirm the formation of carboxylic acids in ${\beta}$-1,3-glucan. From the batch reactions with and without NaBr, the water solubilities of oxidized products were 50.0 and 55.6%, respectively, and in the semi-continuous reactions they were 52.6 and 53.5%, respectively; while the water solubility of the native ${\beta}$-1,3-glucan was less than 1.0%. Finally, as compared to the native ${\beta}$-1,3-glucan, the gel forming ability of the reaction products was greatly increased irrespective of the presence of NaBr or the reaction type.