• Journal for History of Mathematics
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• v.14 no.1
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• pp.73-82
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• 2001

In this article we studied one of the greatest mathematicians and pedagogues, A.N. Kolmogorov. He wrote about five hundreds o( books and articles in the fields of pure mathematics and mathematics education. In this paper we in detail introduced Kolmogorov's history of mathematics education and his theory of mathematical abilities, and elaborated this theory. In addition, we suggested some materials which are aimed to develop mathematical abilities in correspondence to the theory of Kolmogorov.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.03a
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• pp.93-98
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• 1998

본 논문에서는 양자화 결합 네트워크의 시계열 패턴의 기억 특성을 뉴로-칩 상에서 검토하기 위하여, 결합 하중이 $\pm$1 및 0로프로그램 가능한 네트워크를 설계하고 집적화 하였다. 제작된 칩 사이즈는 2.2mm $\times$2.2mm이며 1.2um CMOS 설계기술을 이용하여 7개의 뉴런과 49개의 시냅스 회로를 내장한다. 측정 결과, 설계된 네트워크는 동적 패턴을 성공적으로 기억한다. 또한, 특정한 리미트사이클을 네트워크에 기억시킬 수 있는 결합 하중의 구성방법을 제안한다. 이 방법은 간단한 결합하중과 정밀도의 관점에서 하드웨어 구성에 유용하다.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.564-567
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• 1997

Various ropes used at the industrial fields can be used to experiment analyze tension tester development and also as an educational experiment tool. There fore the purpose of this paper is about rope tension tester development satisfying both safety and educational terms.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.63-65
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• 2004

본 논문은 엘리베이터의 승객보호를 배가하는 안전장치에 관한 것으로 3차원 유한요소해석 코드인 ANSYS를 활용한 구조해석 결과를 설계의 기초 데이터로 사용하였으며, 기존의 제품과 다른 방식을 도입하여 승객과 설비를 보호할 수 있는 설계방법을 제시하고 설계방법에 준한 제작을 통해 안전한 설계를 도모하였다.

• Proceedings of the KIEE Conference
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• summer
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• pp.433-435
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• 2004

본 논문에서는 기존의 가공지선(GW, Ground Wire)을 OPGW(Optical Ground Wire)로 교체공사를 할 경우 나타나는 절연로프에서의 건조대 아크현상을 수치적인 모델링를 통하여 해석할 수 있는 프로그램을 제작하고 현장조건을 입력하여 문제점을 판단하고 해결할 수 있는 방안을 제시하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.49-61
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• 2015

This is the second of two companion papers that describe the performance assessment for flexible rockfall protection systems. Described in a companion paper is the criteria to assess the performance of flexible rockfall protection systems. In this study the performance assessment of domestic rockfall protection fences was implemented using the criteria suggested in the companion paper. It was investigated that the rockfall protection fences for express highways performed well to resist the rockfall energy of 50kJ and the deformed rockfall protection fences right after impacting would not obstruct the vehicle traffic. However, to dissipate the rockfall energy of 50kJ with the level of European standards constantly, the spacing of wireropes was adjusted to be 200mm up to the 8th wirerope from the bottom and spacing-maintainers should be extended to the 8th wirerope. It was figured out that the rockfall protection fences for general highways were required to install spacing-maintainers as those for express highways because they, which did not have spacing-maintenance members, were very prone to the penetration of rockfall even for the very small rockfall impact energies.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.10
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• pp.869-877
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• 2013

Tension force of hanger ropes has been recognized and utilized as an important parameter for health monitoring of suspension bridges. Conventional vibration method based on string theory has been utilized to estimate tension forces of relatively long hanger ropes without any problem, however it is convinced that the vibration method is not applicable for shorter hanger ropes in which the influence of flexural stiffness is not ignorable. Therefore, as an alternative of vibration method, a number of feasibility studies of system identification(SI) technique considering flexural stiffness of the hanger ropes are recently performed. In this study, the influence of support condition of the finite element model utilized for the SI method is investigated with numerical examples. The numerical examples are prepared with the specification of the Kwang-Ahn bridge hanger ropes, and it is revealed that the estimation result of the tension force can be varied from -21.6 % to +35.3 % of the exact value according to the consideration of the support condition of FE model. Therefore, it is concluded that the rotational stiffness of the support spring should be included to the list of the identification parameters of the FE model to improve the result of tension estimation.

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.17-21
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• 2020

Over 60% of South Korea's land consists of mountainous topography, and recently, due to earthquakes, localized heavy rains and road development, the risks of rockfalls are getting higher. As of now, rockfall prevention facilities are being constructed in 70% of Korean roads cut slope and rockfall protections account for about 20% of them. Rockfall protection's supporting capacity is defined by combining performance of wire mesh, pillars and wire ropes. For the existing constructed rockfall protection, standards of pillars that can absorb 48~61 kJ amount of energy, wire ropes and wire mesh are presented in Guidelines for the installation and management of traffic safety facilities, Rockfall prevention facilities by Ministry of Land, Transport and Maritime Affairs (2008). However, each factor's correlation of absorption energy is not presented so it is uncertain. This study will conduct vertical drop test and identify adequacy of rockfall protection net of displacement quantity calculation factor which is delta and evaluate rockfall protection net's absorbable energy through standards of overseas performance evaluation criteria.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.105-110
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• 2017

This paper introduces a heave compensation system for offshore crane when it subjected to unexpected disturbances such as ocean waves, tidal currents or winds and their external force. The dynamic model consists of a crane which is considered to behave in the same manner as a rigid body, a hydraulic driven winch, an elastic rope and a payload. To keep the payload from moving upwards and downwards, PD(Proportional-Derivative) control was applied by using linearization. In order to achieve a better performance, the sliding mode control and the nonlinear generalized predictive control algorithm was applied according to the time-delay. As a result, the oscillating amplitude of the payload was reduced by the control algorithm. Considering the time-delay involved in the system to be one second, nonlinear generalized predictive controller with a robust controller was a suitable control algorithm for this heave compensation system because it made the position of te payload reach the desired position with the minimum error. This paper presented a control algorithm using the robust control and its simulation results.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.589-600
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• 1998

This study was planned to verify the usefulness of Latin square design method in fatigue tests of cables and to see the axial fatigue behavior of wire ropes being used as hangers in suspension bridges. Three parameters : mean stress, stress range. and specimen length, were adopted for verification. The effects of these parameters are in argument except for stress range. Three classes in each parameter were used. Triple replication was performed in each cell to increase the number of replication (or degree of freedoms). The major cause of fatigue failure was fretting fatigue at trellis contact point. Three chosen parameters were proved to be significant. It was verified that the effect of stress range was in agreement with expectation, but the effect of specimen length was contrary to the expectation. It was also observed that the effect of mean stress depended upon the chosen level. Therefore Latin square design method is effective for verifying the parameters that affect fatigue behaviour under orthogonality conditions.