• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.967-969
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• 2013

In this paper, we propose an efficient mult-signature scheme based on a bilinear mapping for shared data in the cloud and prove the security of the proposed scheme using the difficulty of the computational Diffie-Hellman problem. For verification, the scheme is using the sum of the hash values of stored data rather than the entire data, which makes it feasible to reduce the size of the downloaded data.

• Journal of Korea Game Society
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• v.8 no.2
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• pp.57-68
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• 2008

Texture Mapping is a technique for adding realism to an image in 3D graphics Chip. Bilinear filtering mode of this technique needs accesses of 4 texels to process one pixel. In this paper we analyzed the access pattern of texture, and proposed the high performance texture cache which can access 4 texels simultaneously. We evaluated using simulation results of 3D game(Quake 3, Unreal Tournament 2004). Simulation results show that proposed texture cache has high performance on the case where physical size is less then or equal 8KBytes.

• Earthquakes and Structures
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• v.3 no.1
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• pp.59-81
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• 2012

A ductility inverse-mapping method for SDOF systems including passive dampers is proposed which enables one to find the maximum acceleration of ground motion for the prescribed maximum response deformation. In the conventional capacity spectrum method, the maximum response deformation is computed through iterative procedures for the prescribed maximum acceleration of ground motion. This is because the equivalent linear model for response evaluation is described in terms of unknown maximum deformation. While successive calculations are needed, no numerically unstable iterative procedure is required in the proposed method. This ductility inverse-mapping method is applied to an SDOF model of bilinear hysteresis. The SDOF models without and with passive dampers (viscous, viscoelastic and hysteretic dampers) are taken into account to investigate the effectiveness of passive dampers for seismic retrofitting of building structures. Since the maximum response deformation is the principal parameter and specified sequentially, the proposed ductility inverse-mapping method is suitable for the implementation of the performance-based design.

• The Journal of the Korea Contents Association
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• v.2 no.2
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• pp.27-35
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• 2002

This paper describes the implementation of cosmetic surgery simulation system by means of the bilinear warping and interpolation using a pair of control points in order to get the information which can be used to compare the before and the after the surgery. If an user provides a pair of control points, first of all, the system determines warping egion using the points and divides the whole region into four subregions which includes the control points as a corner ones. Then, for each subregion, it calculates warping coefficients for backward mapping using the four known comer points of each subregion. Using those calculated coefficients, the system gets the corresponding position of each pixel on the subregion of original image which matches the subregion of resulting image. Finally, a new pixel value is calculated by bilinear interpolation using the closest four pixel values of the position. The same process is applied to the remaining subregions. Through the experiments, we could find natural aesthetic results without any side effects which unnatural aesthetic results without any side effects which unnaturally distort the boundary of warping region.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.5
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• pp.27-34
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• 1998

This paper is on the discrete model reduction method over disc-type analytic domains. We define hankel singular value over the disc that is mapped by standard bilinear mapping. And the generalized singular perturbation approximation and the direct truncation are generalized to GSPA and DT over a disc. Furthermore, it is shown that the reduced order model over a smaller domaing has a smaller .inf.-norm error bound. And the poposed reduction method is used to obtain the regional pole placement property.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.2
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• pp.57-64
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• 2007

This paper proposed the low power texture cache for mobile 3D graphics accelerators. It is very important to reduce the leakage power in the standby mode for mobile 3D graphics accelerators and the memory access latency of texture mapping in the active mode which needs a large memory bandwidth. The proposed structure reduces the leakage power using variable threshold values of power mode transitions according to the selected texture filtering algorithms of application programs, which has the run time gain for texture mapping. In the trace driven cache simulation the proposed structure shows the best 7% performance gain to the previous MSA cache according to the new performance metric considering both normalized leakage power and run time impact.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.6
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• pp.335-344
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• 2014

As a kind of 2D spatial coordinate transform, image warping is a basic image processing technique utilized in various applications. Though image warping algorithm is composed of relatively simple operations such as memory accesses and computations of weighted average, real-time implementations on embedded vision systems suffer from limited computational power because the simple operations are iterated as many times as the number of pixels. This paper presents a real-time implementation of a look-up table(LUT)-based image warping using an FPGA. In order to ensure sufficient data transfer rate from memories storing mapping LUT and image data, appropriate memory devices are selected by analyzing memory access patterns in an LUT-based image warping using backward mapping. In addition, hardware structure of a parallel and pipelined architecture is proposed for fast computation of bilinear interpolation using fixed-point operations. Accuracy of the implemented hardware is verified using a synthesized test image, and an application to real-time lens distortion correction is exemplified.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.9
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• pp.3286-3301
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• 2014

Jung and Yoo proposed the first image interpolation-based reversible data hiding algorithm. Although their algorithm achieved superior interpolation results, the embedding capacity was insufficient. Lee and Huang proposed an improved algorithm to enhance the embedding capacity and the interpolation results. However, these algorithms present limitations to magnify the original image to any resolution and pixels in the boundary region of the magnified image are poorly manipulated. Furthermore, the capacity and the image quality can be improved further. This study modifies the pixel mapping scheme and adopts a bilinear interpolation to solve boundary artifacts. The modified reference pixel determination and an optimal pixel adjustment process can effectively enhance the embedding capacity and the image quality. The experimental results show our proposed algorithm achieves a higher embedding capacity under acceptable visual distortions, and can be applied to a magnified image at any resolution. Our proposed technique is feasible in reversible data hiding.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.64-68
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• 1996

In this note, we propose the discrete model reduction method over disc-type analytic domains. We define Hankel singular value over the disc that is mapped by standard bilinear mapping. And GSPA(generalized singular perturbation approximation) and DT(direct truncation) are generalized to GSPA and DT over a disc. Furthermore we show that the reduced order model over a smaller domain has a smaller L$_{\infty}$ norm error bound..

• Bulletin of the Korean Mathematical Society
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• v.34 no.2
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• pp.273-285
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• 1997

The aim of this paper is to present theorems on the exitence of zeros for mappings defined on convex subsets of topological vector spaces with values in a vector space. In addition to natural assumptions of continuity, convexity, and compactness, the mappings are subject to some geometric conditions. In the first theorem, the mapping satisfies a "Darboux-type" property expressed in terms of an auxiliary numerical function. Typically, this functions is, in this case, related to an order structure on the target space. We derive an existence theorem for "obtuse" quasiconvex mappings with values in an ordered vector space. In the second theorem, we prove the existence of a "common zero" for an arbitrary (not necessarily countable) family of mappings satisfying a general "inwardness" condition againg expressed in terms of numerical functions (these numerical functions could be duality pairings (more generally, bilinear forms)). Our inwardness condition encompasses classical inwardness conditions of Leray-Schauder, Altman, or Bergman-Halpern types.