• Title, Summary, Keyword: semi-convergence

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Wavelet-Based Semi-Fragile Watermarking with Tamper Detection

  • Lee, Jun-Hyuk;Jung, Hun;Seo, Yeung-Su;Yu, Chun-Gun;Park, Hae-Woo
    • 한국정보컨버전스학회:학술대회논문집
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    • pp.93-97
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    • 2008
  • In this letter, a novel wavelet-based semi-fragile watermarking scheme is presented which exploiting the time-frequency feature of chaotic map. We also analyze the robustness to mild modification and fragility to malicious attack of our scheme. Its application includes tamper detection, image verification and copyright protection of multimedia content. Simulation results show the scheme can detect and localize malicious attacks with high peak signal-to-noise ratio(PSNR), while tolerating certain degree of JPEG compression and channel additive white Gaussian noise(AWGN)

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On the Semi-threading of Knot Diagrams with Minimal Overpasses

  • Chung, Jae-Wook;Jeong, Seul-Gi;Kim, Dong-Seok
    • Kyungpook Mathematical Journal
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    • v.51 no.2
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    • pp.205-215
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    • 2011
  • Given a knot diagram D, we construct a semi-threading circle of it which can be an axis of D as a closed braid depending on knot diagrams. In particular, we consider semi-threading circles of minimal diagrams of a knot with respect to overpasses which give us some information related to the braid index. By this notion, we try to give another proof of the fact that, for every nontrivial knot K, the braid index b(K) of K is not less than the minimum number l(K) of overpasses of diagrams. Also, they are the same for a torus knot.

Semi-supervised Cross-media Feature Learning via Efficient L2,q Norm

  • Zong, Zhikai;Han, Aili;Gong, Qing
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.3
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    • pp.1403-1417
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    • 2019
  • With the rapid growth of multimedia data, research on cross-media feature learning has significance in many applications, such as multimedia search and recommendation. Existing methods are sensitive to noise and edge information in multimedia data. In this paper, we propose a semi-supervised method for cross-media feature learning by means of $L_{2,q}$ norm to improve the performance of cross-media retrieval, which is more robust and efficient than the previous ones. In our method, noise and edge information have less effect on the results of cross-media retrieval and the dynamic patch information of multimedia data is employed to increase the accuracy of cross-media retrieval. Our method can reduce the interference of noise and edge information and achieve fast convergence. Extensive experiments on the XMedia dataset illustrate that our method has better performance than the state-of-the-art methods.

IMEX METHODS FOR PRICING FIXED STRIKE ASIAN OPTIONS WITH JUMP-DIFFUSION MODELS

  • Lee, Sunju;Lee, Younhee
    • East Asian mathematical journal
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    • v.35 no.1
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    • pp.59-66
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    • 2019
  • In this paper we study implicit-explicit (IMEX) methods combined with a semi-Lagrangian scheme to evaluate the prices of fixed strike arithmetic Asian options under jump-diffusion models. An Asian option is described by a two-dimensional partial integro-differential equation (PIDE) that has no diffusion term in the arithmetic average direction. The IMEX methods with the semi-Lagrangian scheme to solve the PIDE are discretized along characteristic curves and performed without any fixed point iteration techniques at each time step. We implement numerical simulations for the prices of a European fixed strike arithmetic Asian put option under the Merton model to demonstrate the second-order convergence rate.

CONVERGENCE THEOREMS FOR GENERALIZED EQUILIBRIUM PROBLEMS AND ASYMPTOTICALLY κ-STRICT PSEUDO-CONTRACTIONS IN HILBERT SPACES

  • Liu, Ying
    • East Asian mathematical journal
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    • v.29 no.3
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    • pp.303-314
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    • 2013
  • In this paper, we introduce an iterative scheme for finding a common element of the set of solutions of a generalized equilibrium problem and the set of common fixed points of a finite family of asymptotically ${\kappa}$-strict pseudo-contractions in Hilbert spaces. Weak and strong convergence theorems are established for the iterative scheme.

IMPLEMENTATION OF A SECOND-ORDER INTERPOLATION SCHEME FOR THE CONVECTIVE TERMS OF A SEMI-IMPLICIT TWO-PHASE FLOW ANALYSIS SOLVER (물-기체 2상 유동 해석을 위한 Semi-Implicit 방법의 대류항에 대한 2차 정확도 확장)

  • Cho, H.K.;Lee, H.D.;Park, I.K.;Jeong, J.J.
    • Journal of computational fluids engineering
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    • v.14 no.4
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    • pp.13-22
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    • 2009
  • A two-phase (gas and liquid) flow analysis solver, named CUPID, has been developed for a realistic simulation of transient two-phase flows in light water nuclear reactor components. In the CUPID solver, a two-fluid three-field model is adopted and the governing equations are solved on unstructured grids for flow analyses in complicated geometries. For the numerical solution scheme, the semi-implicit method of the RELAP5 code, which has been proved to be very stable and accurate for most practical applications of nuclear thermal hydraulics, was used with some modifications for an application to unstructured non-staggered grids. This paper is concerned with the effects of interpolation schemes on the simulation of two-phase flows. In order to stabilize a numerical solution and assure a high numerical accuracy, the second-order upwind scheme is implemented into the CUPID code in the present paper. Some numerical tests have been performed with the implemented scheme and the comparison results between the second-order and first-order upwind schemes are introduced in the present paper. The comparison results among the two interpolation schemes and either the exact solutions or the mesh convergence studies showed the reduced numerical diffusion with the second-order scheme.

An Verification of the Effect of Structured Cognitive Behavioral Intervention Program for Elementary School Students with High Risk Behavior (고위험 문제행동을 보이는 초등학생을 위한 구조화된 인지행동 중재 프로그램의 효과 검증)

  • Lee, A-Reum;Song, Won-Young
    • Journal of the Korea Convergence Society
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    • v.9 no.1
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    • pp.241-251
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    • 2018
  • The study is a preliminary study of the effectiveness of the structured cognitive behavioral arbitration program targeting elementary school students who perform high risk problems based on schools for convergence with local communities. The program is designed to be practiced by semi-trained professionals. To screen high-risk students, total 102 students were tested K-CBCL and those who scored over 60T on problem behavior syndrome scale were recruited. 32 students were selected and devided into intervention group and control group. Intervention group was received 90-minutes-sessions per week, for nine weeks. The program was done by graduate students and undergraduate students majoring counseling and supervised by school psychologist. The internalization group showed significantly lower score in Internalization, anxiety/depression, and externalization group showed externalization, aggressive behavior. but mixed group didn't showed significantly lower score. Implications of the results, limitations and suggestions for future study were mentioned.

A Development of Semi-automatic Trawl-net Surfaces Reconstruction System using Motion Equations and User Interactions (운동 방정식과 사용자 상호작용을 적용한 반자동 트롤 그물 표면 재구축 시스템 개발)

  • Yoon, Joseph;Park, Keon-Kuk;Kwon, Oh-Seok;Kim, Young-Bong
    • Journal of Korea Multimedia Society
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    • v.20 no.8
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    • pp.1447-1455
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    • 2017
  • In a trawl-net simulation, it is very important to process the physical phenomenons resulting from real collisions between a net and fishes. However, because it is very difficult to reconstruct the surface with mass points, many researchers have generally detect the collision using an approximation model employing a sphere, a cube or a cylinder. These approaches occur often result in inaccurate movements of a fish due to the difference between a real-net and a designed-net. So, many systems have manually adjusted a net surface based on actual measurements of mass points. These methods are very inefficient because it needs much times in an adjustment and also causes more incorrect inputs according to a rapid increment in the number of points. Therefore, in this paper, we propose a reconstruction method that it semi-automatically reconstructed trawl-net surfaces using the equation of motion at each mass point in a mass-spring model. To get an easy start in a beginning step of the spread, it enables users to get interactive adjustment on each mass point. We had designed a trawl-net model using geometrical structures of trawl-net and then automatically reconstructed the trawl-net surface using scale-space meshing techniques. Last, we improve the accuracy of reconstructed result by correction user interaction.

MULTIGRID METHOD FOR AN ACCURATE SEMI-ANALYTIC FINITE DIFFERENCE SCHEME

  • Lee, Jun-S.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.7 no.2
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    • pp.75-81
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    • 2003
  • Compact schemes are shown to be effective for a class of problems including convection-diffusion equations when combined with multigrid algorithms [7, 8] and V-cycle convergence is proved[5]. We apply the multigrid algorithm for an semianalytic finite difference scheme, which is desinged to preserve high order accuracy despite of singularities.

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