• Convergence Security Journal
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• v.23 no.1
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• pp.3-8
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• 2023

Multi-domain optical transport networks are not fundamentally interoperable and require an integrated orchestration mechanism and path provision mechanism at the entire network level. In addition, ensuring network survivability is one of the important issues. MPLS-TP (Multi-Protocol Label Switching-Transport Profile) defines various protection/recovery methods as standards, but does not mention how to calculate and select protection/recovery paths. Therefore, an algorithm that minimizes protection/recovery collisions at the optical circuit packet integrated network level and calculates and sets a path that can be rapidly protected/recovered over the entire integrated network area is required. In this paper, we proposed an algorithm that calculates and sets up a path that can be rapidly protected and restored in a T-SDN network composed of multiple ring-mesh topology.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.65-69
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• 2010

Moving Picture Expert Group(MPEG) is the organization foundedin 1998 to establish the standards for compressing and expressing the multimedia contents. The organization has established the technological standards such as MPEG-1, MPEG-2, MPEG-4 and MPEG-7. As the 3D video related standards, there is Multiview Profile which is included in the MPEG-2 video of 1996. However, as the MPEG-2 multiview profile is the standard for compressing the videos from two viewpoints on the object, it is not enough to meet the requirement of multiviewvideo technology. In addition, it does not have the technology on the viewpoint switching that it does not provide the services such as the user interaction. This paper proposes the structure in which the specific viewpoint can be described for video switching in addition to the current MPEG-4 system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.12
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• pp.29-38
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• 2001

Recently, as Internet and its services grow rapidly, IETF(Internet Engineering Task Force) introduced a new switching mechanism, MPLS(Multi-Protocol Label Switching), to solve the problem of the scalability in Internet backbone. In this paper, we implemented the LSR loaded with VC-merging function, which causes LSR's management cost to be significantly reduced. We propose a new VC-merge function which supports differentiated services. In case of network congestion in the output buffer of each core LSR, appling link polices to the output modules of the LSR using the EPD algorithm can prevent the buffer from being overflowed. Simulation was performed for Diffserv by using multiple traffic models and investigated the impact of VC-merge method compared to non VC-merge method. The proposed switch is modeled in VHDL and fabricated using the SAMSUNG $0.5{\mu}m$ SOG process.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1330-1336
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• 2014

QoS techniques and transmitted in real-time communication with the advancement of technology a variety of applications and services are available these days, mobile devices bogeuphwa LTE technology to the development of multimedia services with high quality can be realized. In order to satisfy this condition simply with a router with an increased bandwidth expansion by considering the increase in the routing table of the network scalability problems included. Burst traffic data to be distributed according to the environment is to be centered. To do this, the destination -based routing method to transmit the current paper -based (Source routing) routing settings are required. In this paper, published by the IETF, IP switching system based on standardized protocol Label Switching Multi-Protocol Label Switching (MPLS) network by using the existing Best Effect is difficult to guarantee QoS for multimedia transmission in MPLS network environment using optimized QoS guarantees to transmit the multicast.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1791-1804
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• 2018

To achieve a fast dynamic response and to solve the multi-objective control problems of the output currents, capacitor voltages and system constraints, this paper proposes a deadbeat and hierarchical predictive control with space-vector modulation (DB-HPC-SVM) for five-level nested neutral point piloted (NNPP) converters. First, deadbeat control (DBC) is adopted to track the reference currents by calculating the deadbeat reference voltage vector (DB-RVV). After that, all of the candidate switching sequences that synthesize the DB-RVV are obtained by using the fast SVM principle. Furthermore, according to the redundancies of the switch combination and switching sequence, a hierarchical model predictive control (MPC) is presented to select the optimal switch combination (OSC) and optimal switching sequence (OSS). The proposed DB-HPC-SVM maintains the advantages of DBC and SVM, such as fast dynamic response, zero steady-state error and fixed switching frequency, and combines the characteristics of MPC, such as multi-objective control and simple inclusion of constraints. Finally, comparative simulation and experimental results of a five-level NNPP converter verify the correctness of the proposed DB-HPC-SVM.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.6
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• pp.314-324
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• 2006

In recent years, having the advantages of being small, low in cost and high in efficiency, Half-wave resonant type, (having only one output diode), is used in ZVS Half-Bridge DC/DC converter. This paper presents the operation mode by multi-resonant factors in the Half-wave type multi-resonant converter with direct Buck chopper circuit operated in discontinuous current mode. To study the characteristics of a multi-resonant operation in steady-state, the characteristic impedances in each mode and safe operation-region(S.O.R) are reported. Computer simulation and experimental data are also riven to verify the theoretical results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2359-2369
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• 2009

The study on the multi-level inverter has been increasingly progressing to reduce the switching loss and improve the THD of output current in photovoltaic inverter. Recently, the main topics of multi-level inverter are to reduce the number of devices maintaining the power quality. Therefore, the novel topology was proposed for these problem which is composed of the isolated H-bridge multi-level inverter using the three phase low frequency transformer. The proposed multi-level inverter may not be need for a independent DC power, diode and capacitor. Specially, It has a advantage in generating high voltage source. The proposed approach is verified through simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.7
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• pp.352-360
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• 2003

This paper deals with a simple method in order to analyze and compare the harmonic characteristics in the multi-level inverter. Generally, the magnitude of harmonic components becomes different according to the multi-carrier Pulse Width Modulation(PWM) techniques, the modulation index($M_i$) and the switching frequency The previous papers analyzed the harmonic characteristics from the viewpoint of the space voltage vector. Hence, the calculation of the harmonic vector becomes more difficult and complex in 4-level or over 5-level. However, the proposed method has reduced an amount of calculation and simplified the process of it, using the relationship between the reference voltage and the output phase voltage to the load neutral point. It is applied to the 5-level cascade inverter and the harmonic characteristics for each multi-carrier PWM technique are compared through the simulation.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.151-154
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• 2005

In this paper, we present the enhanced performance of resistive RAM devices with multi-step deposited and annealed oxides. By using multi-step deposition and low temperature multi-step annealins, forming-free Re-RAM is achieved with lower operation voltages and larger resistive ratio than those of conventional Re-RAM with typical single deposited oxide.

• International Journal of Control, Automation, and Systems
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• v.4 no.6
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• pp.669-681
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• 2006

In this work, a new method of design adaptive controllers for SISO systems based on multiple models and switching is presented. The controller selects the model from a given set, according to a switching rule based on output prediction errors. The goal is to design, at each sample instant, a predictive control law that ensures the robust stability of the closed-loop system and achieves the best performance for the current operating point. At each sample the proposed control scheme identifies a set of linear models that best characterizes the dynamics of the current operating region. Then, it carries out an automatic reconfiguration of the controller to achieve the best possible performance whilst providing a guarantee of robust closed-loop stability. The results are illustrated by simulations a nonlinear continuous and stirred tank reactor.