• Journal for History of Mathematics
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• v.24 no.2
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• pp.17-30
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• 2011

This study inquires into the change between two method of indivisibles, which Cavalier suggested. To cope with the objection of use of indivisibles, he modified his first method of indivisibles. Through the analysis of this transition, this study reveals the feature that Cavalier changed into reflecting the density of the figures so as to avoid the paradox related to the indivisibles and this change has the aspect of incomplete lemma-incorporation method according to Lakatos' theory.

• Communications of the Korean Mathematical Society
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• v.28 no.2
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• pp.243-267
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• 2013

This paper is dedicated to study a new class of general nonlinear random A-maximal $m$-relaxed ${\eta}$-accretive (so called (A, ${\eta}$)-accretive [49]) equations with random relaxed cocoercive mappings and random fuzzy mappings in $q$-uniformly smooth Banach spaces. By utilizing the resolvent operator technique for A-maximal $m$-relaxed ${\eta}$-accretive mappings due to Lan et al. and Chang's lemma [13], some new iterative algorithms with mixed errors for finding the approximate solutions of the aforesaid class of nonlinear random equations are constructed. The convergence analysis of the proposed iterative algorithms under some suitable conditions are also studied.

• Communications of Mathematical Education
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• v.20 no.3 s.27
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• pp.361-372
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• 2006

This study was extended as one of the properties of isosceles triangles to polygons(n-angles) by conjectures-proofs-reputations-reformations and developed teaching-learning materials which can be used in high-level classes for middle and high school students.

• Journal of the Korean Mathematical Society
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• v.61 no.3
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• pp.565-602
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• 2024

We study the collective behaviors of two second-order nonlinear consensus models with a bonding force, namely the Kuramoto model and the Cucker-Smale model with inter-particle bonding force. The proposed models contain feedback control terms which induce collision avoidance and emergent consensus dynamics in a suitable framework. Through the cooperative interplays between feedback controls, initial state configuration tends to an ordered configuration asymptotically under suitable frameworks which are formulated in terms of system parameters and initial configurations. For a two-particle system on the real line, we show that the relative state tends to the preassigned value asymptotically, and we also provide several numerical examples to analyze the possible nonlinear dynamics of the proposed models, and compare them with analytical results.

• School Mathematics
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• v.7 no.4
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• pp.353-373
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• 2005

The purpose of this paper is to analysis the basic network problem which can be applied to the mathematically gifted students in elementary school. Mainly, we discuss didactic transpositions of the double counting principle, the game of sprouts, Eulerian graph problem, and the minimum connector problem. Here the double counting principle is related to the handshaking lemma; in any graph, the sum of all the vertex-degree is equal to the number of edges. The selection of these subjects are based on the viewpoint; to familiar to graph theory, to raise algorithmic thinking, to apply to the real-world problem. The theoretical background of didactic transpositions of these subjects are based on the Polya's mathematical heuristics and Lakatos's philosophy of mathematics; quasi-empirical, proofs and refutations as a logic of mathematical discovery.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.5
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• pp.817-832
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• 2015

This paper presents a state feedback based backstepping control algorithm to address the trajectory tracking problem of an underactuated Unmanned Surface Vessel (USV) in the horizontal plane. A nonlinear three Degree of Freedom (DOF) underactuated dynamic model for USV is considered, and trajectory tracking controller that can track both curve trajectory and straight line trajectory with high accuracy is designed as the well known Persistent Exciting (PE) conditions of yaw velocity is completely relaxed in our study. The proposed controller has further been enriched by incorporating an integral action additionally for enhancing the steady state performance and control precision of the USV trajectory tracking control system. Global stability of the overall system is proved by Lyapunov theory and Barbalat's Lemma, and then simulation experiments are carried out to demonstrate the effectiveness of the controller designed.

• Korean Journal of Plant Taxonomy
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• v.41 no.1
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• pp.81-86
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• 2011

Two unrecorded Poaceae species, Anthoxanthum glabrum and Saccharum arundinaceum, are herein newly reported from Korea. Anthoxanthum glabrum (Ae-Gi-Hyang-Mo) was found in Ansan-si, Gyeonggi-do, Sangju-si, Gyeongsangbuk-do and Hwasun-gun, Jeollanam-do. It is distinguished from A. nitens by the length of its spikelet, glume and lemma. Saccharum arundinaceum (Keun-Gae-Sa-Tang-Su-Su) was found in Mapo-gu, Gangnam-gu, Seoul, and Hwasun-gun, Jeollanam-do. It is distinguished from S. spontaneum by hair on the lower glume and according to the length of the hair on the callus of its spikelet. In this study, a description and illustrations of the species and photos of the habitat are provided.