• ETRI Journal
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• v.24 no.2
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• pp.69-81
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• 2002

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP-centric signaling and control architecture based on the generalized multi-protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross-connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS-based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user-network interface and network-network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to generalized MPLS signaling.

• IE interfaces
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• v.9 no.3
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• pp.72-80
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• 1996

As the fiber optic technology is rapidly being deployed in telecommunication networks, particular emphasis is placed on the survivability in designing networks. Most of the survivable network design models proposed to date have connectivity constraints, which cannot precisely define a network topology owing to the multiplicity of feasible ones. In this paper, we propose a k-link survivable network design model incorporating traffic-based survivability constraints which restrict the lost traffic due to a network failure under a prescribed level. Our model is shown to include the existing connectivity models as special cases. Then we present its integer programming formulation, analyze the structural properties, and develop a heuristic for obtaining low cost survivable networks.

• Computers and Concrete
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• v.16 no.3
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• pp.415-428
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• 2015

Study on flexural retrofitting of RC beams using external bars with additional intermediate anchorages at soffit is reported in this paper. Effects of varying number of anchorages in the external bars at soffit were studied by finite element analysis using ANSYS 12.0 software. The results were also compared with available experimental results for beam with only two end anchorages. Two sets of reference and retrofitted beam specimens with two, three, four and five anchorages were analysed and the results are reported. FE modeling and non-linear analysis was carried out by discrete reinforcement modeling using Solid65, Solid45 and Link8 elements. Combin39 spring elements were used for modeling the frictional contact between the soffit and the external bars. The beam specimens were subjected to four-point bending and incremental loading was applied till failure. The entire process of modeling, application of incremental loading and generation of output in text and graphical format were carried out using ANSYS Parametric Design Language.

• Journal of Applied Reliability
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• v.5 no.4
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• pp.465-486
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• 2005

A unreliable network system results in unsatisfied performance. A performance criterion of a network is throughput and availability. One of the most compelling technological advances of this decade has been the advent of deploying wireless networks of heterogeneous smart sensor nodes for complex information gathering tasks, The advancement and popularization of wireless communication technologies make more efficiency to network devices with wireless technology than with wired technology. Recently, the research of wireless sensor network has been drawing much attentions. In this paper, We evaluate throughput and availability of wireless sensor network, which have hierarchical structure based on clustering and estimate the maximum hroughput, average throughput and availability of the network considering several link failure patterns likely to happen at a cluster consisted of sensor nodes. Also increasing a number of sensor nodes in a cluster, We analysis the average throughput and availability of the network.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.513-518
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• 1998

In this paper, a robust fault-tolerant control scheme for robot manipulators overcoming actuator failures is presented. The joint(or actuator) fault considered in this paper is the free-swinging joint failure and causes the loss of torque on a joint. The presented fault-tolerant control framework includes a normal control with normal(non-failed) operation, a fault detection and a fault-tolerant control to achieve task completion. For both no uncertainty case and uncertainty case, a stable normal con-troller and an on-line fault detection scheme are presented. After the detection and identification of joint failures, the robot manipulator becomes the underactuated robot system with failed actuators. A robust adaptive control scheme of robot manipulators with the detected failed-actuators using the brakes equipped at the failed(passive) joints is proposed in the presence of parametric uncertainty and external disturbances. To illustrate the feasibility and validity of the proposed fault-tolerant control scheme, simulation results for a three-link planar robot arm with a failed joint are presented.

• Journal of Korean Vacuum Science & Technology
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• v.7 no.2
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• pp.39-44
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• 2003

Recent ULSI and multilevel structure trends in microelectronic devices minimize the line width down to a quarter micron and below, which results in the high current densities in thin film interconnections. Under high current densities, an EM(electromigration) induced failure becomes one of the critical problems in a microelectronic device. This study is to improve thin film interconnection materials by investigating the EM characteristics in PSG(phosphosilicate glass)/SiO$_2$ passivated Al-l%Si thin film interconnections. Straight line patterns, wide and narrow link type patterns, and meander type patterns, etc. were fabricated by a standard photholithography process. The main results are as follows. The current crowding effects result in the decrease of the lifetime in thin film interconnections. The electric field effects accelerate the decrease of lifetime in the double-layered thin film interconnections. The lifetime of interconnections also depends upon the current conditions of P.D.C.(pulsed direct current) frequencies applied at the same duty factor.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.425-428
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• 2004

Nonlinear finite element analysis is conducted to predict the structural behavior of precast concrete column and steel beam connected by using bolted connections. The Nonlinear FEM program is based on the modified compression field theory which has good accuracy in the concrete structures. The link element is properly used to model the discontinuity between precast concrete column and steel beam. Predictions from the proposed model are compared with experimental results and it is concluded that structural behaviors of the composite structures, such as strength capacity, crack pattern and failure mode, can be predicted quite successfully.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.743-746
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• 2005

The address selection mechanisms have been suggested under the circumstance occurring link failure already. But this paper proposes various considerations to address selection for load sharing without presenting address selection mechanism clearly. The goal of this document is merely referred various situation that have to consider when we make out address selection mechanism in the context of load sharing.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.364-367
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• 2008

Many different types of network equipments are deployed in a large-scale IP network. In this operating environment, network service providers suffer from difficulty in controlling various equipments simultaneously in case network faults happen in their overall or regional network due to physical link failure or abnormal traffic. This paper presents a policy-based methodology to control many different types of network equipments at the same time in abnormal cases. The key idea is that NMS(Network Management System) keeps vendor-neutral control policies in normal times and that when an abnormal case occurs in network, NMS transforms the selected policy into vendor-specific control commands and enforces them to various equipments simultaneously.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.595-598
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• 2014

원전 디지털 계측제어시스템에서 공통원인고장(Common cause failure)의 발생 가능성이 증가함에 따라 이를 방지하기 위해 프로그래머블 논리소자(Field Programmable Gate Array)를 이용한 제어기가 개발되어 활용되고 있다. 그러나, FPGA-기반의 제어기를 구현하는데 사용되는 하드웨어 기술 언어는 그래픽 언어를 이용한 PLC 기반의 개발을 하던 대부분의 원전 계측제어 엔지니어에게 친숙하지 않아 제어기의 구현에 어려움이 있다. 따라서 엔지니어에게 친숙한 그래픽 언어를 이용하여 FPGA 용 제어 프로그램을 작성할 수 있는 통합개발환경이 필요하다. 본 논문에서 구현한 VerilogLinker 는 제어프로그램의 개발을 위한 통합개발환경의 일부로 통합개발환경을 이용한 제어 프로그램의 개발과정 중에서 생성된 Verilog 파일을 FPGA 공급자가 제공하는 상용 소프트웨어인 Libero SoC 와 연결하는 기능을 제공한다.