• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.75-75
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• 2010

기존 할로겐프리 제품은 PVC와 비교하여 유연성이 크게 떨어져 PVC 사용에 대한 규제가 강화되고 있음에도 불구하고, 이를 쉽게 대체하기 곤란하다는 문제점이 있다. 이에 할로겐프리 재료만 사용하여 고난연성, 예를 들면 UL 1581 에 따른 VW-1 규정을 충족하는 고난연성을 가지면서도 경도가 낮아(경도 70수준, Shore A) 재질의 유연성이 확보된 고분자 재료를 개발하는 것이 요구된다. 실험 결과로부터 인장강도 11[Mpa], 신장율 720[%], 가열후 인장강도 잔율 90[%], 가열후 신장잔율 88[%], 산소지수 38.0, 수직난연시험 합격, 경도(Shore A) 70, 백화현상이 나타나지 않는 등 우수한 특성을 보였다.

• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.458-467
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• 2016

In this paper, a strongly coupled method for investigating the interaction between a cable and tow-fish is presented. The nodal position finite element method was utilized to analyze the nonlinear cable dynamics, and 6DOF equations of motion were employed to describe the 3D rigid body motion of the tow-fish. Combining cable and tow-fish systems into a single formulation allowed the two nonlinear systems to be strongly coupled into a unified nonlinear system. This strongly coupled system was numerically integrated in the time domain using a predictor/multi-corrector Newmark algorithm. To demonstrate the validity, efficacy, and applicability of the current approach, two different scenarios (virtual and sea trial) were simulated, and the simulation results were validated using the physical plausibility and the sea trial test.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.15-25
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• 1989

This paper presents the results of the numerical analysis on the behavior of cable-stayed bridge considering geometric nonlinearity of cables. Finite element method is used and geometric nonlinearities are considered on the analysis of cable-stayed bridge. The governing equilibrium equations are derived by the principle of virtual work, and modified Newton-Raphson method and Newmark-${\beta}$ method are employed in response calculations. The validity of this study is demonstrated by comparing the examples with analytical results by other method and testing results.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.52-61
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• 2001

The purpose of this paper is to study on the control of a self-activated cable spooling system for towed away handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specfications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

• Journal of Ocean Engineering and Technology
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• v.23 no.1
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• pp.74-80
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• 2009

In this study, the static and modal analyses to find the characteristic of eigenvalues for a towed cable were with a free boundary condition at the bottom end carried out with numerical study. The resulting numerical code with finite element method was used to study sample problems for a cable with towing speeds. After tracing the equilibrium state with a towing speed through the static analysis, modal analysis on the basis of static results was performed. The static top tension for a critical towing speed is nearly 50 percent of what it was for a free hanging pipe. From static analyses, it is found that towing speed has a noticeable effect on top tension of a towed pipe. At a high towing speed, differences between the first and second periods become larger. Compared to the fundamental period for a free hanging pipe, that for a towed pipe with a critical towing speed is approximately 1.4 times larger. This result is very important point in that the lock in condition and tension of the towed cable system with top excitation can be predicted. The corrected close form solution to solve natural periods for a towed cable was presented in this study. The code is validated by comparison of the results of theoretical and numerical studies. Two results were in very good agreement. This study can contribute to predicting the lock-in condition and tension for a towed cable or pipe with top excitation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.53-65
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• 2010

Conditional Access System (CAS) is a core security mechanism of IPTV SCP (Service and Content Protection) which enables only authenticated user to be able to watch the broadcasting contents. In the past, it was general that CAS was built in Set-Top Box (STB) as hardware or as a detachable cable card. However, numerous researches in Downloadable CAS (DCAS), where users can download CAS code in their STB through their network, have been recently conducted widely due to the lack of security and scalability problem. In this paper, the security requirements of OpenCable based DCAS which is typical example of downloadable IPTV SCP will be derived, the novel authentication and key management scheme will be proposed by using the Authentication Proxy (AP) which is the core DCAS. Also, the benefits of the proposed system will be evaluated by comparison and analysis with preceding research.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.2
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• pp.15-26
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• 1991

The lateral forces such as the earthquake and wind my cause the torsion to be coupled with the lateral bending in the gider, the cross-section of wich has only one axis of symmetry. This induces additional stresses especially in cables arranged in double-planes. Since this effect cannot be considered by using the conventional frame elements, the stiffness and the mass matrices of the geometrically nonlinear thin-walled frame element are developed in this study to model the girder. The equivalent modulus of elasticity proposed by Ernst is used for the cable elements. Verification of the present theory is made through a numerical example. Then, the free vibration of a three dimensional cable-stayed bridge is analyzed to study the coupled flexural-torsional behavior.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1585-1588
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• 2003

일반 가정에 인터넷 서비스를 제공하는 가입자 망은 다양한 종류의 접속방식과 이기종의 장비를 이용하여 일반 가정 가입자에게 단일 형태의 서비스를 제공하고 있다. 그리고 가입자 망의 접속방식에는 망의 종류에 따라서 ADSL, VDSL, DOCSIS 등 다양한 형태가 있다. 이러한 여러 가지 형태를 가지며 분산되어 있는 가입자 망을 효율적이며 집중화된 형태로 관리하기 위해서는 다양한 형태의 접속방식을 지원하는 이기종 장비 및 단말들의 상위 개념으로서 추상적이며 논리적인 객체 관리모델이 필요하다. 본 논문은 통합된 가입자망관리를 가능하게 하는 인터넷 가입자 망에 대한 계층적 모델링 구조를 제시하였다. 그리고 UML 에 근거한 객체지향 방법론을 이용하여 가입자망의 예로서 DOCSIS 의 케이블데이터 가입자망과 VDSL 가입자망에 대하여 관리모델을 적용하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.250-250
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• 2000

The purpose of this paper is to study on the control of a self-activated cable spooling system for towed array handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specifications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.2
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• pp.63-68
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• 1998

This study is aimed to predict the configuration and tension of a towing cable of a side-scan sonar which plays an important role in developing ocean resources. The governing equations of 3-D static equilibrium equations for a flexible cable are derived and solved using a finite difference method. The forces considered in this paper are effective weights, drag forces due to currents and ship moving, and the tension at both ends of the towing cable. The governing equations are non-linear, so an iteration method is applied to solve the equation. A case study is carried out for several different conditions. The result will be useful for predicting the location of a side-scan sonar and to design the towing system.