• Journal of the Korean Ceramic Society
• /
• v.47 no.4
• /
• pp.308-311
• /
• 2010

Porous SiC samples were prepared with three types of wood (poplar, pine, big cone pine) by simply embedding the wood charcoal in a powder mixture of Si and $SiO_2$ at 1600 and $1700^{\circ}C$. The basic engineering properties such as density, porosity, pore size and distribution, and strength were characterized. The samples showed full conversion to mostly $\beta$-SiC with good retention of the cellular structure of the original wood. More rigid SiC struts were developed for $1700^{\circ}C$. They showed similar bulk density ($0.5{\sim}0.6\;g/cm^3$) and porosity (81~84%) irrespective of the type of wood. The poplar sample showed three pore sizes (1, 8, $60\;{\mu}m$) with a main size of $60\;{\mu}m$. The pine sample showed a single pore size ($20\;{\mu}m$). The big cone pine sample showed two pore sizes (10, $80\;{\mu}m$) with a main size of $10\;{\mu}m$. The bend strength was 2.5 MPa for poplar, 5.7 MPa for pine, 2.8 MPa for big cone pine, indicating higher strength with pine.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.4
• /
• pp.41-49
• /
• 2014

In this study, experimental research was carried out to evaluate the structural performance of the reinforced concrete beam using hybrid retrofitting with two materials (groove and embedding FRP rod, CFRP sheet) in existing reinforced concrete buildings. Seven reinforced concrete beams, retrofitted groove and embedding FRP rod (NER series) and groove and embedding FRP rod with CFRP sheet (NERL series), and standard specimen (NBS) were constructed and tested under monotonic loading. Design parameters of test specimens are the amount of groove and embedding FRP rod and lapping CFRP sheet. Test results showed that the maximum load carrying capacity of specimens with groove and embedding FRP rod and groove and embedding FRP rod with CFRP sheet (NERL series) were increased the by 12~46% and 22~77% respectively in comparison with the standard specimen NBS. Test specimens NER series were failed with the adhesion slip and concrete cover separation. And test specimens NERL series were failed with the adhesion slip due to the confining effect of lapping CFRP sheet.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.7
• /
• pp.51-62
• /
• 2015

Of recent interests on high capacity DNA storage, DNA watermarking for DNA copyright protection, and DNA steganography for DNA secret communication are augmented, the reversible DNA watermarking is much needed both to embed the watermark without changing the functionality of organism and to perfectly recover the host DNA sequence. In this paper, we address two ways of DE based reversible DNA watermarking using noncoding DNA sequence. The reversible DNA watermarking should consider the string structure of a DNA sequence, the organism functionality, the perfect recovery, and the high embedding capacity. We convert the string sequence of four characters in noncoding region to the decimal coded values and embed the watermark bit into coded values by two ways; DE based multiple bits embedding (DE-MBE) using pairs of neighbor coded values and consecutive DE-MBE (C-DE-MBE). Two ways process the comparison searching to prevent the false start codon that produces false coding region. Experimental results verified that our ways have more high embedding capacity than conventional methods and produce no false start codon and recover perfectly the host sequence without the reference sequence. Especially C-DE-MBE can embed more high two times than DE-MBE.

• Journal of Korea Water Resources Association
• /
• v.33 no.S1
• /
• pp.37-47
• /
• 2000

The method of delays is widely used for reconstruction chaotic attractors from experimental observations. Many studies have used a fixed delay time ${\tau}_d$ as the embedding dimension m is increased, but this is not necessarily the best choice for obtaining good convergence of the correlation dimension. Recently, some researchers have suggested that it is better to fix the delay time window ${\tau}_w$ instead. Unfortunately, ${\tau}_w$ cannot be estimated using either the autocorrelation function or the mutual information, and no standard procedure for estimating ${\tau}_w$ has yet emerged. However, a new technique, called the C-C method, can be used to estimate either ${\tau}_d\;or\;{\tau}_w$. Using this method, we show that, for small data sets, fixing ${\tau}_w$, rather than ${\tau}_d$, does indeed lead to a more rapid convergence of the correlation dimension as the embedding dimension m in increased.

• The Pure and Applied Mathematics
• /
• v.6 no.1
• /
• pp.39-45
• /
• 1999

The concept of pseudoLindelof spaces is introduced. It is shown that the followings are equivalent: (a) for any two disjoint zero-sets in X, at least one of them is Lindelof, (b) $\mid$vX{\;}-{\;}X$\mid${\leq}{\;}1$, and (c) for any space T with $X{\;}{\subseteq}{\;}T$, there is an embedding $f{\;}:{\;}vX{\;}{\rightarrow}{\;}vT$ such that f(x) = x for all $x{\;}{\in}{\;}X$ and that if $X{\;}{\times}{\;}Y$ is a z-embedded pseudoLindelof subspace of $vX{\;}{\times}{\;}vY,{\;}then{\;}v(X{\;}{\times}{\;}Y){\;}={\;}vX{\;}{\times}{\;}vY$.

• The Pure and Applied Mathematics
• /
• v.22 no.1
• /
• pp.35-56
• /
• 2015

In this paper, we classify all nonconstant smooth CR maps from a sphere $S_{n,1}{\subset}\mathbb{C}^n$ with n > 3 to the Shilov boundary $S_{p,q}{\subset}\mathbb{C}^{p{\times}q}$ of a bounded symmetric domain of Cartan type I under the condition that p - q < 3n - 4. We show that they are either linear maps up to automorphisms of $S_{n,1}$ and $S_{p,q}$ or D'Angelo maps. This is the first classification of CR maps into the Shilov boundary of bounded symmetric domains other than sphere that includes nonlinear maps.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2000.05a
• /
• pp.37-47
• /
• 2000

The method of delays is widely used fur reconstructing chaotic attractors from experimental observations. Many studies have used a fixed delay time ${\tau}_d$ as the embedding dimension m is increased, but this is not necessarily the best choice for obtaining good convergence of the correlation dimension. Recently, some researchers have suggested that it is better to fix the delay time window ${\tau}_w$ instead. Unfortunately, ${\tau}_w$ cannot be estimated using either the autocorrelation function or the mutual information, and no standard procedure for estimating ${\tau}_w$has yet emerged. However, a new technique, called the C-C method, can be used to estimate either ${\tau}_d{\;}or{\;}{\tau}_w$. Using this method, we show that, for small data sets, fixing ${\tau}_w$, rather than ${\tau}_d$, does indeed lead to a more rapid convergence of the correlation dimension as the embedding dimension m is increased.

• Korean Journal of Veterinary Research
• /
• v.56 no.2
• /
• pp.85-89
• /
• 2016

We tested a set of conditions for obtaining optimal tissue quality in preparation for histology in samples of mouse brain. C57BL/6J mice were sacrificed and perfused with 4% paraformaldehyde, after which the brains were removed and dehydrated in 30% sucrose solution. The brains were then divided into four groups according to freezing temperature and usage of optimal cutting temperature (OCT) compound. Next, we stained the sectioned brain tissues with Harris hematoxylin and eosin Y and immunohistochemistry was performed for doublecortin. The best quality tissue was obtained at $-25^{\circ}C$ and by not embedding with the OCT compound. When frozen at $-25^{\circ}C$, the embedded tissue was significantly damaged by crystals, while at $-80^{\circ}C$ there were no meaningful differences between qualities of embedded- and non-embedded tissues. Overall, we identified a set of conditions to obtain quality frozen brain sections. Our developed protocol will help resolve matters associated with damage caused to sectioned brain tissue by crystal formation during freezing.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.17 no.7
• /
• pp.964-969
• /
• 2007

In this paper, we propose the image watermarking method for good compression ratio and satisfactory image quality of the cover image and the embedding image. This method is based on the singular value decomposition and the vector quantization using fuzzy c-mean clustering. Experimental results show that the embedding image has invisibility and robustness to various serious attacks. The advantage of this watermarking method is that we can achieve both the compression and the watermarking method for the copyright protection simultaneously.

• Communications of the Korean Mathematical Society
• /
• v.34 no.1
• /
• pp.279-286
• /
• 2019

Complex Grassmann manifolds $G_{n,k}$ are a generalization of complex projective spaces and have many important features some of which are captured by the $Pl{\ddot{u}}cker$ embedding $f:G_{n,k}{\rightarrow}{\mathbb{C}}P^{N-1}$ where $N=\(^n_k\)$. The problem of existence of cross sections of fibrations can be studied using the Gottlieb group. In a more generalized context one can use the relative evaluation subgroup of a map to describe the cohomology of smooth fiber bundles with fiber the (complex) Grassmann manifold $G_{n,k}$. Our interest lies in making use of techniques of rational homotopy theory to address problems and questions involving applications of Gottlieb groups in general. In this paper, we construct the Sullivan minimal model of the (complex) Grassmann manifold $G_{n,k}$ for $2{\leq}k<n$, and we compute the rational evaluation subgroup of the embedding $f:G_{n,k}{\rightarrow}{\mathbb{C}}P^{N-1}$. We show that, for the Sullivan model ${\phi}:A{\rightarrow}B$, where A and B are the Sullivan minimal models of ${\mathbb{C}}P^{N-1}$ and $G_{n,k}$ respectively, the evaluation subgroup $G_n(A,B;{\phi})$ of ${\phi}$ is generated by a single element and the relative evaluation subgroup $G^{rel}_n(A,B;{\phi})$ is zero. The triviality of the relative evaluation subgroup has its application in studying fibrations with fibre the (complex) Grassmann manifold.