• Journal of Elementary Mathematics Education in Korea
• /
• v.21 no.3
• /
• pp.531-546
• /
• 2017

This study explores the basis for determining priority among the four arithmetical operations in order to provide useful pedagogical content knowledge for teaching the order of operations. The study also discusses the perspective for viewing the order of operations. It presents the following five suggestions based on the results of the discussion. First, teachers should be made to realize that the same result can be obtained on calculation even when subtraction and division are performed first in mixed operations of addition and subtraction and mixed operations of multiplication and division. Second, teachers should understand why the rule of calculating sequentially from the left side of an equation has become customary. Third, teachers should be offered an explanation for the driver of the rule setting that multiplication takes precedence over addition in mixed operations of multiplication and addition. Fourth, the significance of the quantity within parenthesis must be emphasized to teachers. Fifth, teachers must gain an in-depth understanding about the order of operations by getting a description of all the customary and conceptual perspectives on the order of operations when describing the same in the teacher's guide.

• International Journal of Reliability and Applications
• /
• v.8 no.1
• /
• pp.95-109
• /
• 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.

• Journal of Power Electronics
• /
• v.13 no.6
• /
• pp.1008-1015
• /
• 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.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.305-305
• /
• 1996

• Korean Management Science Review
• /
• v.21 no.3
• /
• pp.101-113
• /
• 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.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.473-476
• /
• 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.

• Journal of the military operations research society of Korea
• /
• v.5 no.2
• /
• pp.39-54
• /
• 1979

• Journal of the military operations research society of Korea
• /
• v.5 no.2
• /
• pp.15-25
• /
• 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.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.14 no.1
• /
• pp.108-118
• /
• 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.

• IE interfaces
• /
• v.11 no.2
• /
• pp.199-209
• /
• 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.