• ETRI Journal
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• v.34 no.2
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• pp.292-295
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• 2012

Beyond the simple keyword matching methods in contextual advertising, we propose a rich contextual matching (CM) model adopting a classification method for topic targeting and a query expansion method for semantic ad matching. This letter reports on an investigation into the empirical effects of the CM model by comparing the click-through rates (CTRs) of two practical online news advertising systems. Based on the evaluation results from over 100 million impressions, we prove that the average CTR of our proposed model outperforms that of a traditional model.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.278-281
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• 2000

Matching pursuit algorithm is a signal expansion technique whose efficiency for motion compensated residual image has already been demonstrated in the MPEG-4 framework. However, one of the practical concerns related to applying matching pursuit algorithm to real-time scalable video coding is its massive computation required for finding dictionary elements. In this respective, this paper proposes a fast algorithm, which is composed of three sub-methods. The first method utilizes the property of symmetry in 1-D dictionary element and the second uses mathematical elimination of inner product calculation in advance, and the last one uses frequency property of 2-D dictionary. Experimental results show that our algorithm needs about 30% computational load compared to the conventional fast algorithm using separable property of 2-D gabor dictionary with negligible quality degradation.

• The Journal of Information Systems
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• v.17 no.1
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• pp.155-171
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• 2008

This thesis proposed a method that connecting step motor to image send board which can acquire image to move and remote controlling via streaming image board of PDA(personal digital assistant) based on embedded Linux which is using wireless network There are three embedded Linux system to embody movable image send board. First, though the wireless network a signal of PDA is transmitted to the board which has embedded Linux and a system which is controlled by the expansion I/O port of the board. Second, it's a system streaming realtime image at a PDA which has embedded Linux. The last is a system which controls a process of image board using TCP/IP communication and image send board at PC. These are the system which can use industrial settings and homes. It can also make use of an embodiment method about travelling image robot.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.11
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• pp.17-21
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• 2011

In this paper, we propose a pilot symbol assisted low complexity LS channel estimation method for OFDM in fast time varying channels. The proposed method shows low complexity characteristics in terms of memory space and processing time compared with conventional BEM channel model LS estimation methods.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.50.1-50.1
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• 2016

The incorporation of radiation from massive stars is essential for modeling the dynamics and chemistry of star-forming clouds, yet it is a computationally demanding task for three-dimensional problems. We describe the implementation and tests of radiative transfer module due to point sources on a three-dimensional Cartesian grid in the Eulerian MHD code Athena. To solve the integral form of the radiation transfer equation, we adopt a widely-used long characteristics method with spatially adaptive ray tracing in which rays are split when sampling of cells becomes coarse. We use a completely asynchronous communication pattern between processors to accelerate transport of rays through a computational domain, a major source of performance bottleneck. The results of strong and weak scaling tests show that our code performs well with a large number of processors. We apply our radiation hydrodynamics code to some test problems involving dynamical expansion of HII regions.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.4
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• pp.20-27
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• 1993

The E-polarized scattering problem by a resistive strip grating is analyzed by the method of moments in the spectral domain. For an E-polarized scattering, the induced current density is expected to blow up at both edges. Then the induced surface current density on the strip is expanded in a series of the multiplication of Ultraspherical polynomials with zeroth order and functions with appropriate edge condition. The expansion coefficients are calculated numerically in the spectral domain. When the resistivity of the strip becomes 0, the numerical results agree with those of a perfectly conducting strip srating. And the convergence of the moment-method solutions is very much improved using the basis functions proposed in this paper, compared with that of the existing exponential functions.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.179-188
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• 2000

Multi-disciplinary optimization design concept can provide a solution to many engineering problems. In the field of structural analysis, much development of size or topology optimization has been achieved in the application of research. This paper demonstrates an optimum design of a multi-layer cylindrical tube which behaves thermoelastically. A multi-layer cylindrical tube that has several different material properties at each layer is optimized within allowable stress and temperature range when mechanical and thermal loads are applied simultaneously. When thermal loads are applied to a multi-layer tube, stress phenomena become complicated due to each layer's thermal expansion and the layer thicknesses. Factors like temperature; stress; and material thermal thicknesses of each tube layer are very difficult undertaking. To analyze these problems using an efficient and precise method, the optimization theories are adopted to perform thermoelastic finite element analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1842-1849
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• 1996

This paper presents a full-wave, moment method analysis of a Moreno directional coupler with tow crossed-slots between two crossed rectangular waveguides. the overall structure is divided into several rectangular waveguides and cavities by the use of the equivalence principle to the complex slot regions. this enables a simple and efficient analysis involving the well-known retangular waveguide/cavity Green's functions. For a numerically efficient simulation, the roof-top basis expansion and line testing is used and an acceleration technique is applied to the series summation in the Green's functions. The numerical results are compared with the measurements to verify the correctness of the present analysis.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.566-574
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• 2000

This paper propose a heuristic algorithm based on the Branch-Exchange (BE) method to solve Optimal feeder Routing(OFR) problem for the distribution system planning. The cost function of the OFR problem is consisted of the investment cost representing the feeder installation and the system operation cost representing the system power loss. We propose a properly designed heuristic strategy, which can handle the horizon-year expansion planning problem of power distribution network. We also used the loop selection method which can define the maximum loss reduction in the network to reduce calculation time, and proposed a new index of power loss which is designed to estimate the power loss reduction in the BE. The proposed index, can be considered with both sides, the low voltage side and voltage side branch connected with tie one. The performances of the proposed algorithms and loss index were shown with 32, 69 example bus system.

• Progress in Superconductivity and Cryogenics
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• v.21 no.4
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• pp.34-38
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• 2019

Multilayered high-temperature superconductor coated conductor (CC) tapes are used in an extensive range of applications and are exposed to many stresses such as hoop stress, radial/transverse tensile stress under large Lorentz forces, and thermal stress while cooling if thermal expansion properties differ. Loads induced transversely at the tape surface inevitably create delamination phenomena in the multilayered CC tapes. Thus, delamination behaviors of CC tapes along the c-axis under transverse loading conditions, which can vary based on manufacturing process and constituent layers, must be characterized for applications. The anvil test method was used to mechanically investigate the delamination characteristics of various commercially available Ag-stabilized CC tapes at room temperature and 77 K, finding superior strength at the latter. The wide variations found depended on tape structure and fabrication technique. Fractographic morphologies of delaminated tapes supported the findings under transverse loading conditions.