• Journal of the Institute of Convergence Signal Processing
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• v.5 no.3
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• pp.173-180
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• 2004

In this paper we provide a new image restoration method based on the multiscale regularization in the redundant wavelet transform domain. The proposed method uses the redundant wavelet transform to decompose the single-scale image restoration problem to multiscale ones and applies scale dependent regularization to the decomposed restoration problems. The proposed method recovers sharp edges by applying rather less regularization to wavelet related restorations, while suppressing the resulting noise magnification by the wavelet shrinkage algorithm. The improved performance of the proposed method over more traditional Wiener filtering is shown through numerical experiments.

• Magazine of the Korea Concrete Institute
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• v.17 no.4 s.87
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• pp.25-33
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• 2005

• Magazine of the Korea Concrete Institute
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• v.17 no.4 s.87
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• pp.34-40
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• 2005

• Magazine of the Korea Concrete Institute
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• v.5 no.2
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• pp.181-188
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• 1993

In this study, a numerical method for the material nonlinear analysis of reinforced concrete shell structures including the time dependent effects due to creep and shrinkage is developed. Degenerate shell elements with the layered approach are used. The perfect or strain hardening plasticity model in compression and the linearly elastic model in tension until cracking for concrete are employed. The reinforcing bars are considered as a steel layer of equivalent thickness. Each :steel layer has an uniaxial behaviour resisting only the axial force in the bar direction. A bilinear idealization is adopted to model elasto-plastic stress-strain relationships. For the nonlinear anaysis, incremental load method combined with unbalanced load iterations for each load increment is used. To include time dependent effects of concrete, time domain is divided into several time steps which may have different length. Some numerical examples are presented to study the validity and applicability of the present method. The results are compared with experimental and numerical results obtained by other investigator.

• Computers and Concrete
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• v.19 no.5
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• pp.579-588
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• 2017

Creep and shrinkage are the main types of volume change with time in concrete. These changes cause deflection, cracking and stresses that affect durability, serviceability, long-term reliability and structural integrity of civil engineering infrastructure. Although laboratory test may be undertaken to determine the deformation properties of concrete, these are time-consuming, often expensive and generally not a practical option. Therefore, relatively simple empirically design code models are relied to predict the creep strain. This paper reviews the accuracy of creep and shrinkage predictions of reinforced concrete (RC) shear walls structures strengthened with carbon fibre reinforced polymer (CFRP) plates, which is characterized by a widthwise varying fibre volume fraction. This review is yielded by three commonly used international "code type" models. The assessed are the: CEB-FIP MC 90 model, ACI 209 model and Bazant & Baweja (B3) model. The time-dependent behavior was investigated to analyze their seismic behavior. In the numerical formulation, the adherents and the adhesives are all modelled as shear wall elements, using the mixed finite element method. Several tests were used to demonstrate the accuracy and effectiveness of the proposed method. Numerical results from the present analysis are presented to illustrate the significance of the time-dependency of the lateral displacements and eigenfrequencies modes.

• Journal of Broadcast Engineering
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• v.16 no.4
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• pp.669-679
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• 2011

In this paper, we propose a POCS based irregularly sampled image interpolation method exploiting non-local block-based wavelet shrinkage denoising algorithm. The method provides convex sets to improve the performance. The Delaunay triangulation interpolation is first applied to interpolate the missing pixels of the irregularly sampled image into the regular grids. Then, the non-local block-based wavelet shrinkage denoising algorithm is applied, and the originally observed pixels are enforced. After iteration is performed, the denoising algorithm for non-edge areas is applied to acquire the final result. The experimental results show that the proposed method outperforms the conventional methods.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.860-865
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• 2000

This Paper Proposes the test pieces of X, Y and Z axes to compensate the shape distortion of Selective Laser Sintering(SLS) parts resulting from the phase change during the sintering process. In no case of the proposed compensation test pieces of X, Y axes the accurate rates of shrinkage can be measured with the reduction of curling which is obtained from adjustment of build orientation and the formula used to get scale factors are proposed with the shrinkage rates of them. The scale factors of X, Y and Z axes are generated by building up proposed compensation test pieces. The generated scale iactors are required to satisfy the dimensional accuracy even if there are changes of the build position and the size of SLS parts in the build chamber. For this reason, it is proposed that the build positions and the size be considered to be noise factors against the compensation test pieces and a method is also proposed that scale factors be selected to robustly maintain the dimensional accuracy of SLS parts under the actual operating conditions with the application of the Taguchi Method.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.5
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• pp.496-503
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• 2007

Although weld-induced deformation is inevitable in shipbuilding, it is important to reduce it as low as possible during fabrication for a more efficient production of ships' blocks. The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates, and in addition internal and external constraints much more influence upon weld-induced deformation of thin plates. This paper deals with the application of the mechanical tensioning method to butt weld of thin plates to reduce the transverse and longitudinal deformation. in order to investigate the quantitative effect of tensioning method upon the reduction of angular deformation and shrinkage in longitudinal and transverse direction of weld line, butt welding test have been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. Numerical simulation has been also carried out to compare the weld-induced deformation and residual stress. From the present study, it has been found that the tensioning method is very effective on reduction of weld-induced residual stress as well as weld-induced deformation.

• Journal of Sericultural and Entomological Science
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• v.28 no.2
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• pp.65-73
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• 1986

These studies are carried out to improve silk availability for anticrease by useing methacrylate monomer polymerization method with in silk fiber. For this purpose, degree of anticrease, stiffness and shrinkage of various silk fabrics, included finish or not, after repeat of washings and polyster fabric was compared as standard. The adopted samples are ; 1. Polyester, Georgette, Woven density…90cm-85g/m 2. Silk, Twill, Degumed, Light, Woven density…90cm-90g/m 3. Silk, Twill, Degumed, Heavy, Woven density…90cm-200g/m 4. Silk, Stain, Degumed, Light, Woven density…90cm-90g/m The reached results are as followings. 1. The results of improving on anticrease by the finished method were about ten per cent increase against their original samples. 2. The light density silks showed satisfactory improve for anticrease, but the heavy one remained as rather poor condition. 3. The results for degree of textile stiffness were investigated to make sure reserve their textile feeling and observed to be good condition upon the finish work. 4. Textile shrinkage after the repeat of soap wash was investigated on indivisual test sample and silk fabrics showed more shrinkage than polyester which it seemed to be tentering shrinkage druning their general finishing processes. 5. The investigation showed that anticrease, stiffness and shrinkage of the sample textile were more or less deteriorated regardless silk or polyester by the repeat of washings. These matters are considered that such results were obtained because of the fiber fatigue nature. 6. The report reached that silk textiles should be used by dry cleaning methed after finish of any resin finish to reserve their improved anticrease nature.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.195-201
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• 2014

Purpose: This study was designed to compare the amount of polymerization shrinkage of dual-cure resin cements according to different polymerization modes and to determine the effect of light activation on the degree of polymerization. Materials and methods: Four kinds of dual-cure resin cements were investigated: Smartcem 2, Panavia F 2.0, Clearfil SA Luting and Zirconite. Each material was tested in three different polymerization modes: self-polymerization only, immediate light polymerization and 5 minutes-delayed light polymerization. The time-dependent polymerization shrinkage-strain was evaluated for 30 minutes by Bonded-disk method at $37^{\circ}C$. Five recordings of each material with three different modes were taken. Data were analyzed using one-way ANOVA and multiple comparison Scheffe′test (${\alpha}$=.05). Results: All materials, except Panavia F 2.0, exhibited the highest polymerization shrinkage-strain through delayed light-activated polymerization. No significant difference between light activation modes was found with Panavia F 2.0. All materials exhibited more than 90% of polymerization rate in the immediate or delayed light activated group within 10 minutes. Conclusion: As a clinical implication of this study, the application of delayed light activation mode to dual-cure resin cements is advantageous in terms of degree of polymerization.