• Title/Summary/Keyword: order of operations

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우리나라 초등학교 수학에서의 혼합계산 순서에 대한 연구 (A Study on the Order of Mixed Calculations in Korean Elementary School Mathematics)

  • 고준석;최종현;이승은;박교식
    • 한국초등수학교육학회지
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    • 제21권3호
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    • pp.531-546
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    • 2017
  • 본 연구에서는 계산 순서를 지도하는데 유용한 교수법적 내용 지식을 제공하기 위해 사칙계산 사이의 우선권은 어떠한 근거로 결정되었는지 살펴보고, 계산 순서를 바라보는 입장에 관해 논의하였다. 이러한 논의 결과를 바탕으로 다음 다섯 가지 제언을 결론으로 제시한다. 첫째, 교사들에게 덧셈과 뺄셈의 혼합계산 및 곱셈과 나눗셈의 혼합계산의 경우, 각각 뺄셈과 나눗셈부터 계산해도 동일한 계산 결과를 구할 수 있다는 것을 확인하는 기회를 제공할 필요가 있다. 둘째, 교사들에게 식의 왼쪽부터 차례대로 계산하는 규칙이 관습으로 자리 잡은 이유에 관해 논의할 수 있는 기회를 제공할 필요가 있다. 셋째, 교사들에게 덧셈과 곱셈의 혼합계산에서 곱셈이 덧셈보다 우선한다는 규칙 설정의 동인을 설명해 보는 기회를 제공할 필요가 있다. 넷째, 교사들에게 괄호가 있는 식에서 하나의 수량이라는 괄호의 의미를 강조할 필요가 있다. 다섯째, 교사용 지도서에서 계산 순서의 입장을 기술할 때는 계산 순서의 관습적, 개념적 입장을 모두 기술하여 교사들의 계산 순서에 대한 이해를 심화시킬 필요가 있다.

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On Some New Stochastic Orders of Interest in Reliability Theory

  • Kayid, M.;El-Bassiouny, A.H.;Al-Wasel, I.A.
    • International Journal of Reliability and Applications
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    • 제8권1호
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    • pp.95-109
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    • 2007
  • The purpose of this paper is to study new notions of stochastic comparisons and ageing classes based on the total time on test transform order. We give relationships to other stochastic orders and aging classes given previously. Several preservation properties under the reliability operations of random minima and series system are given.

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Modeling and Analysis of the Fractional Order Buck Converter in DCM Operation by using Fractional Calculus and the Circuit-Averaging Technique

  • Wang, Faqiang;Ma, Xikui
    • Journal of Power Electronics
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    • 제13권6호
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    • pp.1008-1015
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    • 2013
  • By using fractional calculus and the circuit-averaging technique, the modeling and analysis of a Buck converter with fractional order inductor and fractional order capacitor in discontinuous conduction mode (DCM) operations is investigated in this study. The equivalent averaged circuit model of the fractional order Buck converter in DCM operations is established. DC analysis is conducted by using the derived DC equivalent circuit model. The transfer functions from the input voltage to the output voltage, the duty cycle to the output voltage, the input impedance, and the output impedance of the fractional order Buck converter in DCM operations are derived from the corresponding AC-equivalent circuit model. Results show that the DC equilibrium point, voltage ratio, and all derived transfer functions of the fractional order Buck converter in DCM operations are affected by the inductor order and/or capacitor order. The fractional order inductor and fractional order capacitor are designed, and PSIM simulations are performed to confirm the correctness of the derivations and theoretical analysis.

실시간 주문 확답을 위한 데이터 마이닝 기반 운용 계획 모델 (Applications of Data Mining Techniques to Operations Planning for Real Time Order Confirmation)

  • 한현수;오동하
    • 경영과학
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    • 제21권3호
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    • pp.101-113
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    • 2004
  • In the rapidly propagating Internet based electronic transaction environment. the importance of real time order confirmation has been more emphasized, In this paper, using data mining techniques, we develop intelligent operations decision model to allow real time order confirmation at the time the customer places an order with required delivery terms. Among various operation plannings used for order fulfillment. mill routing is the first interface decision point to link the order receiving at the marketing with the production planning for order fulfillment. Though linear programming based mathematical optimization techniques are mostly used for mill routing problems, some early orders should wait until sufficient orders are gathered for optimization. And that could effect longer order fulfillment lead-time, and prevent instant order confirmation of delivery terms. To cope with this problem, we provide the intelligent decision model to allow instant order based mill routing decisions. Data mining techniques of decision trees and neural networks. which are more popular in marketing and financial applications, are used to develop the model. Through diverse computational trials with the industrial data from the steel company. we have reported that the performance of the proposed approach is effective compared to the present heuristic only mill routing results. Various issues of data mining techniques application to the mill routing problems having linear programming characteristics are also discussed.

재취급을 최소화하기 위한 수출컨테이너 장치위치 결정법 (Locating export containers in order to minimize the number of rehandles)

  • 김갑환;박영만
    • 한국경영과학회:학술대회논문집
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    • 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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    • pp.473-476
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    • 1996
  • In order to reduce the number of rehandles during the loading operation of export containers in port container terminals, the storage location of each arriving container should be determined considering of its weight. We formulate the problem by a dynamic programming model to get the optimal storage location.

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Single-period Stochastic Inventory Problems with Quadratic Costs

  • Song, Moon-Ho
    • 한국국방경영분석학회지
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    • 제5권2호
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    • pp.15-25
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    • 1979
  • Single-period inventory problems such as the newspaper boy problem having quadratic cost functions for both shortages and overage are examined to determine the optimal order level under various principles of choice such as minimum expected cost, aspiration level, and minimax regret. Procedures for finding the optimum order levels are developed for both continuous and discrete demand patterns.

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다차원 개체를 위한 차이등급 clustering (The Difference Order Clustering for Multi-dimensional Entities)

  • 이철;강석호
    • 한국경영과학회지
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    • 제14권1호
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    • pp.108-118
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    • 1989
  • The clustering problem for multi-dimensional entities is investigated. A heuristic method, which is named as Difference Order Clustering (DOC) is developed for the grouping of multi-dimensional entities DOC method has an advantage of identifying the bottle-neck entities. Comparisons among the proposed DOC method, modified rank order clustering (MODROC) method, and lexicographical rank order clustering using minimum spanning tree (lexico-MMSTROC) are illustrated by a part type selection problems.

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전동기 제조업의 공정과 자재의 동기화에 관한 연구 (Synchronization of Production Operations and Material Supplies in the Electric Motor Manufacturing)

  • 송정수;김재균;이지형
    • 산업공학
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    • 제11권2호
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    • pp.199-209
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    • 1998
  • In manufacturing industries, one of the critical issues is to synchronize the sequence of production operations with materials needed at each operation to improve productivity. In order to solve this synchronization problem. We develop a code system entitled 'Work-Order-Number' for automated storage/retrieval systems(AS/RS) in this paper. The Work-Order-Number is designed for the purpose of integrating the engineering information. material handling, production and operations scheduling, point of production, and AS/RS systems. This paper implemented the Work-Order-Number in the electric motor manufacturing. The results of the implementation showed the reduction of the number of workers in material handling and cost-loss due lo a late delivery.

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