• Kyungpook Mathematical Journal
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• v.55 no.3
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• pp.541-548
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• 2015

In this paper, concepts of quasi-normal and dually quasi-normal relations are introduced. Characterizations of these relations are obtained. In addition, particulary we show that the anti-order relation ${\nleqslant}$ ($={\leqslant}^C$) is a (dually) quasi-normal relation if and only if the partially ordered set (X, ${\leqslant}$) is an anti-chain.

• Korean Journal of Computational Design and Engineering
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• v.11 no.1
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• pp.1-10
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• 2006

This paper addresses B-spline curve approximation of a set of ordered points to a specified toterance. The important issue in this problem is to reduce the number of control points while keeping the desired accuracy in the resulting B-spline curve. In this paper we propose a new method for error-bounded B-spline curve approximation based on adaptive selection of dominant points. The method first selects from the given points initial dominant points that govern the overall shape of the point set. It then computes a knot vector using the dominant points and performs B-spline curve fitting to all the given points. If the fitted B-spline curve cannot approximate the points within the tolerance, the method selects more points as dominant points and repeats the curve fitting process. The knots are determined in each step by averaging the parameters of the dominant points. The resulting curve is a piecewise B-spline curve of order (degree+1) p with $C^{(p-2)}$ continuity at each knot. The shape index of a point set is introduced to facilitate the dominant point selection during the iterative curve fitting process. Compared with previous methods for error-bounded B-spline curve approximation, the proposed method requires much less control points to approximate the given point set with the desired shape fidelity. Some experimental results demonstrate its usefulness and quality.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.1
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• pp.59-64
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• 2011

In 2001, the notion of a fuzzy poset defined on a set X via a triplet (L, G, I) of functions with domain X ${\times}$ X and range [0, 1] satisfying a special condition L+G+I = 1 is introduced by J. Negger and Hee Sik Kim, where L is the 'less than' function, G is the 'greater than' function, and I is the 'incomparable to' function. Using this approach, we are able to define a special class of fuzzy posets, and define the 'skeleton' of a fuzzy poset in view of major relation. In this sense, we define the linear discrepancy of a fuzzy poset of size n as the minimum value of all maximum of I(x, y)${\mid}$f(x)-f(y)${\mid}$ for f ${\in}$ F and x, y ${\in}$ X with I(x, y) > $\frac{1}{2}$, where F is the set of all injective order-preserving maps from the fuzzy poset to the set of positive integers. We first show that the definition is well-defined. Then, it is shown that the optimality appears at the same injective order-preserving maps in both cases of a fuzzy poset and its skeleton if the linear discrepancy of a skeleton of a fuzzy poset is 1.

• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.71-76
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• 2018

The purpose of this study is to analyze the factors affecting the roundabout accidents near schools. This study gives particular attentions discussing characteristics by pedestrian accident severity using the ordered logit models. In pursuing the above, 63 roundabouts installed before 2014 are surveyed for modeling. the traffic accident data from 2014 to 2016 are collected from TAAS data set of Road Traffic Authority. Such 35variables explaining the accidents as environment, human, geometries, school and roundabout factor are selected from literature reviews. The main results are as follows. First, the ordered logit models (${\rho}^2$ of 0.272, $x^2$ of 24.723) which is statistically significant have been developed. Second, environment factor variable is analyzed to be day or night ($X_1$ ), human factor variables are evaluated to be driver gender($X_4$), older driver($X_5$), pedestrian gender($X_7$) and children pedestrian($X_8$ ). Third, geometries factor variable are analyzed to be speed limit sign($X_{16}$) and median barrier($X_{21}$), school factor variables are evaluated to be hump-type crosswalk($X_{25}$), CCTV($X_{26}$) and school zone sign($X_{27}$), roundabout factor are analyzed to be roundabout sign($X_{30}$) and number of circulatory roadway lane($X_{32}$). Finally, this study could give some implications to decreasing the accidents severity at roundabout near schools.

• Journal of KIISE:Databases
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• v.32 no.3
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• pp.326-333
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• 2005

Many XML applications use XPath Patterns as a query language for XML documents. Two XPath patterns may have containment relationship, and the containment problem between two XPath patterns is a problem that determines whether one XPath pattern contains another XPath Pattern. Although the containment problem occurs in many applications, it is known as a co-NP complete. A homomorphism problem, which is a sufficient condition for the containment problem, is solved in polynomial time. We first discuss applications that replace the containment problem with the homomorphism problem, and maintaining homomorphism information among XPath patterns will benefit those applications. Then, we propose a lattice structure, called POX (Partially Ordered Set of XPath Patterns), and develop algorithms for maintaining it. As our analyses show, the algorithms can efficiently maintain POX in polynomial time.

• Communications of the Korean Mathematical Society
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• v.19 no.2
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• pp.355-373
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• 2004

An extended directed triple system of order v, denoted by EDTS(v), is a pair (V, (equation omitted)) where V is a v-set and (equation omitted) is a set of transitive triples of elements of V such that every ordered pair of elements of V is contained in exactly one member of (equation omitted). We obtain a necessary and sufficient condition for the existence of cyclic EDTS(v)s, and when k=1 or 2, we also obtain a necessary and sufficient condition for the existence of k-rotational EDTS(v)s.

• Journal of applied mathematics & informatics
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• v.3 no.1
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• pp.11-24
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• 1996

The focus of this research is the class of sequential al-gorithms called predictive sorting algorithms for sorting a given set of n elements using pairwise comparisons. The order in which these pairwise comparisons are made is defined by a fixed sequence of all un-ordered pairs of distinct integers{1,2 ···,n} called a sort sequence. A predictive sorting algorithm associated with a sort sequence spec-ifies pairwise comparisons of elements in the input set in the order defined by the sort sequence except that the comparisons whose out-comes can be inferred from the preceding pairs of comparisons are not performed. in this paper predictive sorting algorithms are obtained based on known sorting algorithms and are shown to be required on the average O(n log n) comparisons.

• East Asian Journal of Business Economics (EAJBE)
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• v.3 no.2
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• pp.21-25
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• 2015

Investment process on startup companies faces several difficulties based on the characteristics of this type of companies, such as lack of historical data, current operating losses and absence of comparable companies. In this paper we focus in a new methodology based on ordered weighted averaging (OWA) operators. OWA operators are useful instruments that enable the aggregation of information; in other words, from a data set we are able to obtain a single representative value of that set. The investment methodology presented consists on the application of OWA operators to the targeted startup companies based on the capacity of cash-flow generation and also on the planned scenario of future growth for each company. This paper shows that the methodology proposed can serve as a valuable tool, complementing the qualitative criteria (which, obviously, should not be ignored) for assessing and selecting a start-up investment.

• Communications of the Korean Mathematical Society
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• v.30 no.4
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• pp.349-361
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• 2015

A fence is an ordered set that the order forms a path with alternating orientation. Let F = (F;${\leq}$) be a fence and let OT(F) be the semigroup of all order-preserving self-mappings of F. We prove that OT(F) is coregular if and only if ${\mid}F{\mid}{\leq}2$. We characterize all coregular elements in OT(F) when F is finite. For any subfence S of F, we show that the set COTS(F) of all order-preserving self-mappings in OT(F) having S as their range forms a coregular subsemigroup of OT(F). Under some conditions, we show that a union of COTS(F)'s forms a coregular subsemigroup of OT(F).

• Journal of Astronomy and Space Sciences
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• v.38 no.2
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• pp.93-103
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• 2021

In this work, the problem of resonance caused by some gravitational potentials due to Mercury and a third body, namely the Sun, together with some non-gravitational perturbations, specifically coronal mass ejections and solar wind in addition to radiation pressure, are investigated. Some simplifying assumptions without loss of accuracy are employed. The considered force model is constructed. Then the Delaunay canonical set is introduced. The Hamiltonian of the problem is obtained then it is expressed in terms of the Deluanay canonical set. The Hamiltonian is re-ordered to adopt it to the perturbation technique used to solve the problem. The Lie transform method is surveyed. The Hamiltonian is doubly averaged. The resonance capture is investigated. Finally, some numerical simulations are illustrated and are analyzed. Many resonant inclinations are revealed.