• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.164-169
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• 2010

Proper Orthogonal Decomposition (POD) is applied to the analysis of 2-dimensional cylinder wake flow. Time histories of flow variables were obtained by the incompressible CFD analysis. By using the method of snapshots the correlation matrix was constructed, and then eigenvalues, POD modes and time coefficients were calculated. Finally the flow field was reconstructed by using a few of the lower POD modes, and compared to the original ones.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.102-107
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• 2007

Since the Matrix Pencil (MP) method can be performed to estimate multiple DOAs by using only single snapshot, this method is suitable for short data length or when the environment is dynamic. As the number of array increases, the computational load increases due to complex number computation. This paper presents an approach based on a unitary matrix pencil (MP) algorithm to reduce the computational load. Unitary transformation for the MP method has been suggested and formulated successfully. The computer simulation shows that the error rate of proposed method agree with that of MP for different SNR values.

• ETRI Journal
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• v.36 no.3
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• pp.460-468
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• 2014

This paper addresses the problem of joint time of arrival (TOA) and direction of arrival (DOA) estimation in impulse radio ultra-wideband systems with a two-antenna receiver and links the joint estimation of TOA and DOA to the sparse representation framework. Exploiting this link, an orthogonal matching pursuit algorithm is used for TOA estimation in the two antennas, and then the DOA parameters are estimated via the difference in the TOAs between the two antennas. The proposed algorithm can work well with a single measurement vector and can pair TOA and DOA parameters. Furthermore, it has better parameter-estimation performance than traditional propagator methods, such as, estimation of signal parameters via rotational invariance techniques algorithms matrix pencil algorithms, and other new joint-estimation schemes, with one single snapshot. The simulation results verify the usefulness of the proposed algorithm.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.2
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• pp.141-159
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• 2009

In this article, we consider a weighted CVT-based reduced-order modelling for Burgers equation. Brief review of the CVT (centroidal Voronoi tessellation) approaches to reduced-order bases are provided. In CVT-reduced order modelling, we start with a snapshot set just as is done in a POD (Proper Orthogonal Decomposition)-based setting. So far, the CVT was researched with uniform density ($\rho$(y) = 1) to determine the basis elements for the approximatin subspaces. Here, we shall investigate the technique of CVT with nonuniform density as a procedure to determine the basis elements for the approximating subspaces. Some numerical experiments including comparison of two CVT (CVT-uniform and CVT-nonuniform)-based algorithm with numerical results obtained from FEM(finite element method) and POD-based algorithm are reported.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.97-97
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• 2000

In this paper, a signal processing algorithm for software GPS receiver is proposed. The signal processor takes snapshot of the sampled If signal from the RF section of the GPS receiver. All the processing for code and carrier tracking and correlation are implemented using the digital signal processing techniques. In order to achieve fast code acquisition, correlation of the incoming GPS signal is performed using the FFT method, After code acquisition, to reduce the Doppler shift effect and increase the accuracy, the interpolation or the tracking are performed. The performance of the proposed processing algorithm is first evaluated using matlab/simulink. A signal acquisition board for sampling and logging GPS IF signal form the Mitel GPS RF chip set is constructed. In order to analyze the performance of the designed algorithm the experiments are performed and the results are analyzed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.272-277
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• 2006

High speed electric trains have nonlinear loads including converters and inverters for the contol synchronous motors. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. Direct application of the harmonic assessment to the snapshot measurements would result in ambiguous conclusions depending on which instant is sampled. A cumulative probablistic approach is the most commonly used method to solve time varying harmonics. This paper provides an in depth analysis on harmonics field measurement of the high speed electric train loads, harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE std. 519-1992, and harmonics simulation using EDSA program for the case study.

• Journal of Public Diplomacy
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• v.1 no.1
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• pp.36-56
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• 2021

The Amazon fires in summer 2019 triggered an incendiary Twitter debate between French president Emmanuel Macron and Brazilian president Jair Bolsonaro that engaged political leaders, celebrities, and audiences worldwide. Currently, diplomats-in-chief connect to the global public through completely open debates, often without proper advice from foreign-affairs ministers, which may result in misunderstandings and conflicts among world leaders. Hence, this study argues that these interactions must be supported by Nicholas Cull's seven lessons in public diplomacy. The main topic on hand is presidential public diplomacy performed through digital means in cyberspace. Thus, after distinguishing cyberspace, digital diplomacy, and cyberdiplomacy, the literature review focuses on presidential public diplomacy, presidential diplomacy on Twitter, and Cull's seven lessons. Subsequently, the case study method provides a snapshot of the debate between Macron and Bolsonaro over the Amazon fires. This study concludes by answering the research question and indicating grist for the mill with regard to future developments.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.11a
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• pp.350-362
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• 2002

A new architecture called the Storage Area Network(SAN) was developed in response to the requirements of high availability of data, scalable growth and system performance In order to use SAN more efficiently, must SAN operating systems support storage virtualization concepts that allow users to view physical storage devices attached to SAN as a large volume virtually. A logical volume manager Days a key role in storage virtualization it realizes the storage virtualization by mapping logical addresses to physical addresses. In this paper, we design and implement an efficient and flexible mapping method for logical volume manager. The mapping method in this paper supports a snapshot that preserves a volume image at certain time and on-line reorganization to allow users to add or remove storage devices to SAN even while the system is running.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.350-362
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• 2002

A new architecture called the Storage Area Network(SAN) was developed in response to the requirements of high availability of data scalable growth, and system performance. In order to use SAN more efficiently, most SAN operating systems support storage virtualization concepts that allow users to view physical storage devices attached to SAN as a large volume virtually. A logical volume manager plays a key role in storage virtualization. It realizes the storage virtualization by mapping logical addresses to physical addresses. In this paper, we design and implement an efficient and flexible mapping method for logical volume manager. The nin method in this paper supports a snapshot that preserves a volume image at certain time and on-line reorganization to allow users to add or remove storage devices to SAN even while the system is running.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.718-731
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• 2003

SAN(Storage Area Network) was developed in response to the requirements of high availability of data, scalable growth, and system performance. In order to use the SAN more efficiently, most of the SAN operating software supports storage virtualization concepts that allow users to view physical storage devices of the SAN as a large volume. A logical volume manager plays a key role in storage virtualization. It realizes the storage virtualization by mapping logical addresses to physical addresses. In this paper, we design and implement an efficient and flexible mapping method for the logical volume manager. Additionally we also design and implement a free space management method for flexible mapping. Our mapping method supports a snapshot that preserves a volume image at certain time and on-line reorganization to allow users to add or remove storage devices to and from the SAN even while the system is running. To justify our mapping method, we compare it with the mapping method of the GFS (Global File System) through various experiments.