• 대한수학회지
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• 제49권4호
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• pp.703-713
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• 2012

In this paper we study ${\omega}$-limit sets and attraction of non-autonomous discrete dynamical systems. We introduce some basic concepts such as ${\omega}$-limit set and attraction for non-autonomous discrete system. We study fundamental properties of ${\omega}$-limit sets and discuss the relationship between ${\omega}$-limit sets and attraction for non-autonomous discrete dynamical systems.

• Korean Journal of Mathematics
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• 제5권2호
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• pp.211-215
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• 1997

In this paper, we introduce two notions of compactness defined by sequential convergence and compare them.

• 소성∙가공
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• 제9권6호
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• pp.604-614
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• 2000

In this paper, the mechanical characteristics and fundamental mechanism of a roll-formed tube during the hydroforming process are investigated in order to obtain the ewly localization of the tube hydroforming skills which are the core production techniques for the super light weight and high safety of the car body. Also, the theoretical influences of the material variables and the processes on the formability in the tube hydroforming are studied. In addition, the techniques to evaluate the forming limit of the bulging process of a tube are developed.

• 대한수학회지
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• 제61권4호
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• pp.761-778
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• 2024

A separable minimal surface is represented by the form of f(x) + g(y) + h(z) = 0, where f, g and h are real-valued functions of x, y and z, respectively. We provide exact equations for separable minimal surfaces with elliptic functions that are singly, doubly and triply periodic minimal surfaces and completely classify all them. In particular, parameters in the separable minimal surfaces change the shape of the surfaces, such as fundamental periods and its limit behavior, within the form f(x) + g(y) + h(z) = 0.

• Steel and Composite Structures
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• 제17권5호
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• pp.705-719
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• 2014

Composite steel-concrete box girders are frequently used in bridge construction for their economic and structural advantages. An integrated metaheuristic based optimization procedure is proposed for discrete size optimization of straight multi-span steel box girders with the objective of minimizing the self-weight of girder. The metaheuristic algorithm of choice is the Cuckoo Search (CS) algorithm. The optimum design of a box girder is characterized by geometry, serviceability and ultimate limit states specified by the American Association of State Highway and Transportation Officials (AASHTO). Size optimization of a practical design example investigates the efficiency of this optimization approach and leads to around 15% of saving in material.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.255-258
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• 2005

In this paper, we verify that the bandwidth of the optimized disk-loaded monopole antenna with electromagnetically coupled feed obtained using a genetic algorithm is broader than the theoretical bandwidth limit of 2/Q by simulation as well as by measurement. The measured bandwidth of the optimized antenna (kr : 0.599) is about 42% from 380 MHz to 580 MHz (VSWR<5.8). The efficiency measurement of the antenna is over 90% for the frequency band of operation.

• East Asian mathematical journal
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• 제36권1호
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• pp.25-34
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• 2020

The classical limit theorems like strong law of large numbers, central limit theorems and law of iterated logarithms are fundamental theories in probability and statistics. These limit theorems are proved under additivity of probabilities and expectations. In this paper, we investigate strong law of large numbers under sub-linear expectation which generalize the classical ones. We give strong law of large numbers under sub-linear expectation with respect to the partial sums and some conditions similar to Petrov's. It is an extension of the classical Chung type strong law of large numbers of Jardas et al.'s result. As an application, we obtain Chung's strong law of large number and Marcinkiewicz's strong law of large number for independent and identically distributed random variables under the sub-linear expectation. Here the sub-linear expectation and its related capacity are not additive.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.3-5
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• 2004

In order to speed up basic concept is to enhance high speed, curve limit speed, cross limit speed, acceleration/deceleration speed. It is important to optimal interface fundamental technology of vehicle, rail, electrical power, and signal system. Tilting train has advantage minimizing investment cost of infra railway system for increasing train limit speed in curve. the developed tilting train should be operated to commercial service speed 180Km/h of 200Km/h at KNR upgrade railroad. This paper proposed the basic model of system engineering for developing of TTX, tilting EMU (maximum operation speed : 180km/h) with speed-up of conventional railway system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.350-352
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• 2002

In order to speed up basic concept is to enhance high speed, curve limit speed, cross limit speed, acceleration/deceleration speed. It is important to optimal interface, fundamental technology of vehicle, rail, electrical power, and signal system. Tilting train has advantage minimizing investment cost of infra railway system for increasing train limit speed in curve. the developed tilting train should be operated to commercial service speed 180km/h of 200km/h at KNR upgrade railroad. This paper proposed the basic model of system engineering for developing of tilting EMU(maximum operation speed : 180km/h) with speed-up of conventional railway system.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.26-29
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• 2004

In order to speed up basic concept is to enhance high speed, curve limit speed, cross limit speed, acceleration/deceleration speed. It is important to optimal interface fundamental technology of vehicle, rail, electrical power, and signal system. Tilting train has advantage minimizing investment cost of infra railway system for increasing train limit speed in curve. the developed tilting train should be operated to commercial service speed 180Km/h of 200Km/h at KNR upgrade railroad. This paper proposed the basic model of system engineering for developing of tilting EMU (maximum operation speed : 180km/h) with speed-up of conventional railway system.