• Journal of Mechanical Science and Technology
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• v.14 no.1
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• pp.84-92
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• 2000

A new bounce back boundary method of the second order in error is proposed for the lattice Boltzmann fluid simulation. This new method can be used for the arbitrarily irregular lattice geometry of a non-slip boundary. The traditional bounce back boundary condition for the lattice Boltzmann simulation is of the first order in error. Since the lattice Boltzmann method is the second order scheme by itself, a boundary technique of the second order has been desired to replace the first order bounce back method. This study shows that, contrary to the common belief that the bounce back boundary condition is unilaterally of the first order, the second order bounce back boundary condition can be realized. This study also shows that there exists a generalized bounce back technique that can be characterized by a single interpolation parameter. The second order bounce back method can be obtained by proper selection of this parameter in accordance with the detailed lattice geometry of the boundary. For an illustrative purpose, the transient Couette and the plane Poiseuille flows are solved by the lattice Boltzmann simulation with various boundary conditions. The results show that the generalized bounce back method yields the second order behavior in the error of the solution, provided that the interpolation parameter is properly selected. Coupled with its intuitive nature and the ease of implementation, the bounce back method can be as good as any second order boundary method.

• Korean Management Science Review
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• v.21 no.3
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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.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.1
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• pp.43-53
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• 1996

This study was initiated to investigate (1) the current sizing system for mail-order clothing, (2) consumers' preference for sizing systems, and (3) consumers' satisfaction with garment size. The apparel items and the sizes available at various mail-order companies in Korea were also reviewed. This investigation of consumers' preferences for various size description systems includes a survey of 410 men and women who had purchased garments by mail-order. The data were analyzed by Statistical Analysis System/pc. The major results are as follows; 1. The sizing system of mail-order clothing was different by garment items. The number of apparel sizes available for mail-order purchasing was three or less. The most mail∼order garments were labeled by the numerical size codes of body girth nleasurements or letter code (S, M, L). 2. The size description system most prefered by female subjects(N : 360) was the numerical size code of a body measurement(55.4%). The combination of bust-hips-height measurements size codes were prefered by 13.3% . The pictogram was least premiered by the subjects. 3. The apparel items that subjects wanted to buy using mail-order were underwear, home -weat and night-wear. The heavy users of mail-order purchasing, however, also wanted to purchase expensive garments requiring precise fit. The subjects aged from 20's to 80's wanted to purchase childern's wear by mail. 4. The desire for diversity of garment item and size of mail-order apparel was relatively high. The subjets also wanted to purchase special size garments by mail-order, e. g., garment sizes for full or tall figure.

• Journal for History of Mathematics
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• v.20 no.2
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• pp.59-72
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• 2007

There are three kinds of order of instruction in mathematics, that is, historical order, theoretical organization and lecturing organization-order. Simply speaking, each lecturing organization-order is a combination of two preceding orders. The problem is how to combine between them. In a recent paper, we concretely considered this problem for the case of the concept of angle. The present paper analogously discuss with the concept of vectors. To begin with, we investigate theoretical organization and historical order of the concept of vectors as materials for the construction of its lecturing organization-order. It enables us to establish 4 stages in historical order of the concept of vectors proper to its theoretical organization. As a consequence, we suggest several criteria and forms for constructing its lecturing organization-order.

• Journal of Navigation and Port Research
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• v.33 no.7
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• pp.477-482
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• 2009

In this paper the order picking problem in warehouses is considered, a topic which has received considerable attention from the international academic body in recent years. The order picking problem deals with the retrieval of order items from prespecified locations in the warehouse, and its objective is usually the minimization of travel time or travel distance. Hence, a well-thought order picking policy in combination with an appropriate storage policy will enhance warehouse efficiency and reduce operational costs. This paper starts with a literature overview summarizing approaches to routing order pickers, assigning stock-keeping units to pick locations and designing warehouse layouts. Since the layout design might affect both storage and routing policies, the three factors are interdependent with respect to order picking performance. To test these interdependencies, a simulation experiment was set up, involving two types of warehouse layout, four types of storage policy, five well-known heuristics and five sizes of order picking list. Our results illustrate that from the point of view of order picking distance minimization it is recommended to equip the warehouse with a third cross aisle, although this comes at the cost of a certain space loss. Additionally, we propose a set of most appropriate matches between order picking heuristics and storage policies. Finally, we give some directions for further research and recommend an integrated approach involving all factors that affect warehouse efficiency.

• Journal of applied mathematics & informatics
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• v.32 no.1_2
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• pp.153-159
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• 2014

In this paper, we introduce a pair of higher-order symmetric dual models/problems. Weak, strong and converse duality theorems for this pair are established under the assumption of higher-order invexity. Moreover, self duality theorem is also discussed.

• The Pure and Applied Mathematics
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• v.25 no.3
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• pp.193-201
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• 2018

In this paper, we discuss central index oriented and slowly changing function based some growth properties of composite entire functions.

• Korean Journal of Mathematics
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• v.26 no.3
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• pp.405-424
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• 2018

In this paper we study some comparative growth properties of composite entire functions on the basis of relative (p, q)-th order and relative (p, q)-th lower order of entire function with respect to another entire function where p and q are any two positive integers.

• ICROS
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• v.1 no.1
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• pp.50-50
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• 1995

It has been pointed out in the literature that the Routh approximation method for order reduction has limitations in treating transfer functions with the denominator-numerator order difference not equal to one. The purpose of this paper is to present a new algorithm based on the Routh approximation method that can be applied to general rational transfer functions, yielding reduced models with arbitrary order.

• Kyungpook Mathematical Journal
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• v.18 no.1
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• pp.37-46
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• 1978

The first part of this note is concerned with a neighbourhood base characterisation of locally order-convex spaces. The notions of order*-inductive limits and order ultrabornologicity in the class of locally order-convex spaces are introduced and studied in the latter part. These are the non-convex generalisation of o-inductive limits and o-bornological spaces.