• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.257-263
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• 2019

Multilayered structures include lamination by relatively thick plies and thin interlayers. For efficient peridynamic analysis of dynamic fracturing multilayered structures, the interlayer is modeled using ghost peridynamic particles while the ply is formulated via real peridynamics. With the nonlocal ghost interlayer, one may keep the discretization resolution low for the ply. In this study, the characteristics of dynamic wave propagation through the nonlocal ghost interlayer in peridynamic analysis are investigated. It is observed that the interlayer not only binds adjacent plies, but also significantly influences energy transfer between plies, and thereby their deformation and motion. In addition, near a surface or boundary, peridynamic particles do not have a full nonlocal neighborhoods. This causes the effective material properties near the surface to be different from those in the bulk. Surface correction based on neighborhood volumes is employed. The impact of surface correction on wave propagation in multilayered structures is investigated.

• Current Optics and Photonics
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• v.5 no.2
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• pp.147-154
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• 2021

Microfluidic chip technology is a research focus in biology, chemistry, and medicine, for example. However, microfluidic chips are rarely applied in imaging, especially in ghost imaging. Thus in this work we propose a ghost-imaging system, in which we deploy a novel microfluidic chip modulator (MCM) constructed of double-layer zigzag micro pipelines. While in traditional situations a spatial light modulator (SLM) and supporting computers are required, we can get rid of active modulation devices and computers with this proposed scheme. The corresponding simulation analysis verifies good feasibility of the scheme, which can ensure the quality of data transmission and achieve convenient, fast ghost imaging passively.

• Journal of computational fluids engineering
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• v.10 no.3 s.30
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• pp.70-76
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• 2005

A two-layer incompressible time-accurate Euler solver is applied to analyze flow fields around a submerged body moving at a critical speed near a pycnocline. Discontinuities in the dependent variables across the material interface are captured without any dissipation or oscillation using the ghost fluid method on an unstructured grid. It is shown that the material interlace has significant effects on forces acting on a submerged body moving near a pycnocline regardless of the small difference in densities of two layers. Contrary to the shallow water waves, a submerged body can reach a critical speed at very low Froude number due to the small difference in the densities of the two layers.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.8-12
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• 2016

In this paper, we theoretically and experimentally analyze the impact of speckle size of pseudo-thermal light source on ghost imaging. A larger size of speckle can bring improvements in SNR and visibility. At the same time, the edge blur of the retrieved image will become more serious. We also present a setup which can mitigate the edge blur of larger speckle while maintaining the advantages of higher SNR and visibility by changing the speckle size of the object beam with a concave lens.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2C
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• pp.129-140
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• 2003

This paper is a result of the study that develops ghost eliminator which removes ghost among the ghosted analog or digital TV signal. We proposed innovative multilevel SIGN algorithm which is operated more stable and speedy than conventional LMS or SIGN algorithm. We compared its convergence speed with SIGN algorithm by experiment. We can eliminate ghost more speedy and stable than conventional method by using the multi-level SIGN algorithm which is presented in this paper. Multi-level SIGN algorithm can be used in any other applications instead of LMS or SIGN algorithm for stability and speed.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.57-58
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• 2001

플라스틱 붕장어 통발은 양승이나 투승과정의 실수로 혹은 황천시 부표나 멍의 파손 또는 저인망과 같은 다른 업종의 어선이 어구를 망가뜨리는 바람에 바다에 버려지게 된다. 그러나 이들 통발 가운데 대부분은 원래의 어구 구성에서 분리되었을 뿐이지 어구 본래의 기능은 그대로 가지고 있어, Ghost Fishing의 기회가 어느 어구보다 높다고 할 수 있다. 특히 통발에 수산 생물이 들어오는 이유에 대해서는, 대부분의 통발이 미끼를 통발 안에 넣어서 조업하고 있어 미끼에 유인된 수산생물이 통발 안으로 들어오는 것으로 생각하거나, 혹은 통발의 차폐작용 때문에 들어온다는 것 또는 통발 미끼가 통발을 통하여 다량으로 수중에 뿌려지므로 통발 속에는 먹이가 있을 것이라는 학습에 의해 미끼가 없는 통발에도 들어온다는 가설 등이 있는 만큼 통발이 온전하게 수중에 머물러 있으면, 언제든지 Ghost Fishing이 일어날 가능성이 있다. (중략)

• Journal of the Society of Naval Architects of Korea
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• v.41 no.4
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• pp.17-29
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• 2004

Internal waves are computed using a ghost fluid method on an unstructured grid. Discontinuities in density and dynamic pressure are captured in one cell without smearing or oscillations along a multimaterial interface. A time-accurate incompressible Navier-Stokes/Euler solver is developed based on a three-point backward difference formula for the physical time marching. Artificial compressibility is introduced with respect to pseudotime and an implicit method is used for the pseudotime iteration. To track evolution of an interface, a level set function is coupled with the governing equations. Roe's flux difference splitting method is used to calculate numerical fluxes of the coupled equations. To get higher order accuracy, dependent variables are reconstructed based on gradients which are calculated using Gauss theorem. For each edge crossing an interface, dynamic pressure is assigned for a ghost node to enforce the continuity of total pressure along the interface. Solitary internal waves are computed and the results are compared with other computational and experimental results.

• Archives of Pharmacal Research
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• v.18 no.6
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• pp.402-409
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• 1995

The effects of calcium channel blockers (CAB's) verapamil, diltiazem and nicardipine, on erythrocyte ghost membranes have been studied. Using the fluorospectroscopic method, it was observed that the fluidity of the inner layer of ghost membranes was increased with an increase of drug concentrations but did not any changes in the fluidity of the outer layer. These drugs showed protectuve effect against hypotonic hemolysis of erythrocytes. Thus, the expansion of surface area in response to corpuscular volume of erythrocytes in the presence of CAB's is seemed to play an important role in protecting hypotonic hemolysis of erythrocytes.

• Archives of Pharmacal Research
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• v.17 no.3
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• pp.182-189
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• 1994

The effect of lipophilicity on the mechanisms of drug absorption through biomembranes was investigated empolying HPLC system and the fluorescence technique. Human erythrocyte ghost membranes were used as a model biomembrane. A series of four parabens (methyl, ethyl, rpopyl, and butyl) and p-hydroxybenzoic acid were used as the model drugs for lipophilicities and their partition coefficients were measured in Sorensen's phosphate buffer solution (pH 5)/octanol system. Absorption amount of parabens through erythrocyte ghost membranes increased with an increase of lipophilicity resulted from the addition of methylene group to the n-alkyl chain of parabens. And the effect of parabens on the fluidity of ghost membrane also increased with an increase of their lipophilicities.

• Journal of architectural history
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• v.10 no.3 s.27
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• pp.7-23
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• 2001

We Koreans are very proud of this nation's cultural history over some five millenniums. But most of the relics found in the nation date back up to two thousand years. Under this circumstance, we are wondering the gap and missing of three thousand years. In our traditional literature of history, [Chiwoo] was a military god of supreme dignity and virtue. He was a symbol of brave and strong warriors and since the antiquity, he has been kept alive deeply in the mind of the Korean race. Considering findings through this study, the researcher could provide a conclusion as described below. 1) The name of Paekje's designed tiles was initially made by a Japanese scholar who had first found the antique relic. According to studies by a few of Korean researchers, the name is usually called despite its relation with a historical background of the excavated objects has not been fully studied. 2) After the patterned objects of the Korean antique Kingdom, Japanese researchers reported that [Chiwoo] was a military god as exorcist and probably represented something in the form of a ghost, although there were arguments that the military god was the very being to influence the image of the ghost. This report suggests that the Japanese community didn't downgrade the military god onto the level of a ghost. 3) One of our antique nations, Paekje at that time sought to determine the origin and culture of the Koreans by making multiple exchange relations with China, and probably accepting cultures of the Chinese Han nation and those of the Chinese South and North Dynasty period. Based on findings from a relevant literature, [Sulyigi], people of Paekje attempted to show express the image of Chiwoo in their own unique ways and then deliver the strong bravery of [Chiwoo] to us, or their descendents. This can explain that those findings as above mentioned are consistent with the designed tiles of Paekje, and that the tiles should not be named as the design of ghost. 4) The designed tiles involved elements of Taoism and Buddhism and substantially considered the spirit of four gods which was mobilized for the tomb construction and selection at that time. But this should never be a reason why all of the horned figures seen in tomb wall paintings are collectively treated as ghosts. 5) From the view of historic literature, we can no doubt say that the Heavenly Emperor [Chiwoo] was our ancestor. It is not better to say that the relic stuffs as excavated should be referred to the design of ghost image only in that they have yet to be associated historically with other relics. This claim would be newly changed as it becomes clear with historical remains that our antique ancestors kept doing positive activities along the coast of the antique kingdom, Balhae.