• Biomolecules & Therapeutics
• /
• v.2 no.1
• /
• pp.34-38
• /
• 1994

In order to investigate the structure-activity relationships of the stereoisomers of angiotensin converting enzyme inhibitors, captopril and its derivatives were selected as model compounds. In vitro enzymatic activities of them depend on the symmetry at the asymmetric carbons. Especially, the alanyl carbon should have the S configuration to be biologically active. But the demethylated captopril having the achiral carbon also shows the activity although it is less active than captopril. Seven stereoisomers of captopril and its derivatives were chosen and their acidic and ionic forms were used for molecular dynamics simulations. Four computer simulations were practiced for each model compound in order to obtain the good condition for simulation to explain the experimental structure-activity relationships. From the computer simulation results, relativistic movements of three well-known pharmacophoric sites, carboxylate carbon, carbonyl oxygen, and sulfur atoms, were analyzed. Good results were obtained from the aqueous solution molecular dynamics simulation with ionic forms of model compounds. Active model compounds have the pharmacophoric areas of 6.08 to 6.38 $\AA$$^2$and the similarity in the geometrical data. But inactive ones have the largely deviated values of 4.51 to 4.87 $\AA$$^2$from those of active ones.

• Journal of Fisheries and Marine Sciences Education
• /
• v.28 no.4
• /
• pp.1042-1056
• /
• 2016

To evaluate the wake regions of six artificial reefs (ARs) frequently used in the marine forest creation project in Korea, we consider the effect of water flow directions on the wake regions and accordingly propose a wake region diagram, which is characterized by parameters such as wake volume fluctuations, averaged wake volume, fundamental symmetric angle, secure angle, and principal direction. To demonstrate the parameters, seven water flow directions (0 to $90^{\circ}$) were considered and consequently the variations in wake volumes were investigated by using the concept of wake volume, adopting element-based finite volume method, and utilizing numerical flow domain and boundary conditions. From the analysis results, it was shown that the wake region diagrams have a period of either 45 or $90^{\circ}$ according to the geometrical symmetry of each artificial reef. Also, it was found that the secure angle ranges fluctuate depending on the shapes and sizes of the artificial reefs considered. Thus, it is demanded to consider those parameters during installation of artificial reefs for establishing a larger wake region and accordingly attracting more marine fauna and flora in the region.

• Structural Engineering and Mechanics
• /
• v.72 no.2
• /
• pp.181-190
• /
• 2019

Topology optimization of structures seeking the best distribution of mass in a design space to improve the structural performance and reduce the weight of a structure is one of the most comprehensive issues in the field of structural optimization. In addition to structures stiffness as the most common objective function, frequency optimization is of great importance in variety of applications too. In this paper, an efficient multi-objective Bi-directional Evolutionary Structural Optimization (BESO) method is developed for topology optimization of frequency and stiffness in continuum structures simultaneously. A software package including a Matlab code and Abaqus FE solver has been created for the numerical implementation of multi-objective BESO utilizing the weighted function method. At the same time, by considering the weaknesses of the optimized structure in single-objective optimizations for stiffness or frequency problems, slight modifications have been done on the numerical algorithm of developed multi-objective BESO in order to overcome challenges due to artificial localized modes, checker boarding and geometrical symmetry constraint during the progressive iterations of optimization. Numerical results show that the proposed Multiobjective BESO method is efficient and optimal solutions can be obtained for continuum structures based on an existent finite element model of the structures.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.9
• /
• pp.1405-1417
• /
• 2006

The geometrical structures, potential energy surfaces, and energetics for the ligand exchange reactions of tetracoordinated platinum $(PtY_2L_2\;:\;Y,\;L=Cl^-,\;OH^-,\;OH_2,\;NH_3)$ complexes in the ligand-solvent interaction systems were investigated using the ab initio Hartree-Fock (HF) and Density Functional Theory (DFT) methods. The potential energy surfaces for the ligand exchange reactions used for the conversions of $(PtCl_4\;+\;H_2O)^{^\ast_\ast}\;to\;[PtCl_3(H_2O)\;+\;Cl^-]$ and $[Pt(NH_3)_2Cl_2\;+\;H_2O]$$[Pt(NH_3)_2Cl_2\;+\;H_2O]$ to $[Pt(NH_3)_2Cl(H_2O)\;+\;Cl^-] $ were investigated in detail. For these two exchange reactions, the transition states $([PtY_2L_2{\cdot}{\cdot}{\cdot}L^\prime])^{^\ast_\ast} $ correspond to complexes such as $(PtCl_4{\cdot}{\cdot}{\cdot}H_2O)^{^\ast_\ast}$ and $[Pt(NH_3)_2Cl_2{\cdot}{\cdot}{\cdot}H_2O]^{^\ast_\ast}$, respectively. In the transition state, $([PtCl_4{\cdot}{\cdot}{\cdot}H_2O]^{^\ast_\ast}$ and $[Pt(NH_3)_2Cl_2{\cdot}{\cdot}{\cdot}H_2O]]^{^\ast_\ast})$ have a kind of 6-membered $(Pt-Cl{\cdot}{\cdot}{\cdot}HOH{\cdot}{\cdot}{\cdot}Cl)$ and $(Pt-OH{\cdot}{\cdot}{\cdot}Cl{\cdot}{\cdot}{\cdot}HN)$ interactions, respectively, wherein a central Pt(II) metal directly combines with a leaving $Cl^-$ and an entering $H_2O$. Simultaneously, the entering $H_2O$ interacts with a leaving $Cl^-$. No vertical one metal-ligand interactions $([PtY_2L_2{\cdot}{\cdot}{\cdot}L^\prime]) $ are found at the axial positions of the square planar $(PtY_2L_2)$ complexes, which were formed via a vertically associative mechanism leading to $D_{3h}$ or $C_{2v}$-transition state symmetry. The geometrical structure variations, molecular orbital variations (HOMO and LUMO), and relative stabilities for the ligand exchange processes are also examined quantitatively. Schematic diagrams for the dissociation reactions of {PtCl4(H2O)n(n=2,4)} into {$PtCl_3(H_2O)_{(n-2)}\;+\;Cl^-(H_2O)_2$} and the binding energies {$PtCl_4(H_2O)_n$(n = 1-5)} of $PtCl_4$ with water molecules are drawn.

• Korean Institute of Interior Design Journal
• /
• no.28
• /
• pp.33-43
• /
• 2001

Mario Botta is one of the modern architects who established his own architectural world on the basis of the architectural spirit of Modernism. His works have been a good theme not only for those who study architecture but also for those who study the relationship between architecture and the surrounding environment and there have been many published papers and reports on his works. However, most of them stressed on the importance of the external appearance of architecture or on the relationship between architecture and the surrounding environment. There have been relatively few studies that have dealt intensively with interior space. The aim of this study is to find the characteristics of interior space in public buildings that were designed by Botta and to analyze them from the view design principles and design elements. For this purpose, the five most important public buildings were selected and the public space of the building like the central hall, the lobby, and the foyer were analyzed. Through this study, the followings are realized. A) Spatial features: $\circled1$ Refined and graceful interiors where the principle of symmetry was applied, $\circled2$ Centripetal interiors surrounded by thick walls, $\circled3$ Interior design lit by skylights above the central area, B) Formative features: $\circled1$ The shapes of the external and internal spaces are identical, $\circled2$ Simple geometrical shapes were applied in defining the shapes of internal spaces, $\circled3$ Skylights and light wells were combined and were utilized as form elements, $\circled4$ Architectural vocabularies of Corbusier such as stairs, round pillars, and bridges were developed and utilized, $\circled5$ Utilized the geometry that resembled his architecture as a form element to the furniture, C) material pattern features: $\circled1$ Plainly expressed the patterns of bricks that appear in the course of construction, $\circled2$ Made and used horizontal stripe patterns using stones of different colors.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.6C
• /
• pp.815-823
• /
• 2004

A hue-based attention operator and a combinational integral projection function(CIPF) are proposed to extract the normalized regions of face and facial features robustly against illumination variation. The face candidate regions are efficiently detected by using skin color filter, and the eyes are located accurately nil robustly against illumination variation by applying the proposed hue- and symmetry-based attention operator to the face candidate regions. And the faces are confirmed by verifying the eyes with the color-based eye variance filter. The proposed CIPF, which combines the weighted hue and intensity, is applied to detect the accurate vertical locations of the eyebrows and the mouth under illumination variations and the existence of mustache. The global face and its local feature regions are exactly located and normalized based on these accurate geometrical information. Experimental results on the AR face database［8］ show that the proposed eye detection method yields better detection rate by about 39.3% than the conventional gray GST-based method. As a result, the normalized facial features can be extracted robustly and consistently based on the exact eye location under illumination variations.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.41 no.6
• /
• pp.121-126
• /
• 2004

An efficient multi face detection technique is proposed based on hierarchical context-free attention operators in which multiple faces are efficiently detected from a noisy and complex background. A noise-tolerant generalized symmetry transform (NTSGT) is applied hierarchically, as a context free attention operator, to the input pyramidal image for the high speed global location of the regions of face candidates (ROFCs) with a single mask. For the face verification, local NTGST is applied within each ROFC to confirm the existence of the detailed facial features. First, by globally applying NTGST which introduces the average pyramid method and focusing to the input image with complex background, ROFCs with recognizable resolution are detected robustly. Morphological operations are applied only to the each detected ROFCs to emphasize the facial features like eyes and lips. Then, eyes are detected by locally appling NTGST to the ROFCs and only faces are detected by verifying the existence of the geometrical features of the faces relatively to the location of eyes. The experimental results show that the proposed method can efficiently detect multiple faces from a noisy or complex background with 93.5% detection rate.

• Fashion & Textile Research Journal
• /
• v.15 no.2
• /
• pp.173-181
• /
• 2013

This research analyzed the expression trend about the slit which composes the open space by the visual concept and then introduced the imbedded aesthetic value in it. Based on it, this work aims at showing the evidence on the slit as a utilizing tool for various design applications and providing the basic materials in order to develop the creative design production in the fashion area in the future. Specifically, for the theoretical background in this research, the concept of slit and its chronological changes were reviewed through literature. For the empirical analysis on the slit, a total of 226 designs with its application were analyzed from collection pieces in the four major collections including Paris, Milan, New York, and London from 2006S/S to 2012S/S. As a result of analysis, types of slit appeared as a slash, opening, slit, or a mix of them. These were applied to many different items of clothing, and among which, one-piece or dress was adopted most for application. In regard to space form, perpendicularity was used most frequently. But other various forms like cross and geometrical pattern were also used as well as curve, oblique line and horizontality. As to the arrangement of slit, single type was most frequently used. However, in addition to it, other types were also applied, producing both the functionality and the decorative detail such as bilateral symmetry, free irregularity, and a combination of regular and repeated layout which makes an effect of single pattern. Aesthetic values imbedded in slit were revealed as functionality, sensuality, spatiality, and decorativeness.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.3 no.3
• /
• pp.177-182
• /
• 2002

In this paper, we present a mathematical theory and algorithm consoucting some fractal sets. Among such fractal sets, the degree-n bifurcation set as well as the Julia sets is defined by extending the concept of the Mandelbrot set to the complex polynomial $Z^n$+c($c{\epsilon}C$, $n{\ge}2$). Some properties of the degree-n bifurcation set and the Julia sets have been theoretically investigated including the symmetry, periodicity, boundedness, and connectedness. An efficient algorithm constructing both the degree-n bifurcation let and the Julia sets is proposed using theoretical results. The mouse-operated software called "MANJUL" has been developed for the effective construction of the degree-n bifurcation set and the Julia sets in graphic environments with C++ programming language under the windows operating system. Simple mouse operations can construct ann magnify the degree-n bifurcation set as well af the Julia sets. They not only compute the component period but also save the images of the degree-n bifurcation set and the Julia sets to visually confirm various properties and the geometrical structure of the sets. A demonstration has verified the useful versatility of MANJUL.of MANJUL.

• The Journal of Korean Academy of Prosthodontics
• /
• v.42 no.5
• /
• pp.524-534
• /
• 2004

Statement of problem: The meaning of the beauty has a little different nature according to a time, culture, and nation. Purpose : This study was undertaken to estimate the geometric esthetic criteria for Korean woman by analysis of facial photograph in a smiling. Material and methods: The facial photographs of 678 Korean beautiful woman were collected from Miss Korea candidates(from 1971 to 2003 year). The dento-facial composition was measured and analyzed geometrically on computer monitor using $Adobe^{(R)}$ $Photoshop^{(R)}$ 7.0. The statistical significance of the differences among the 4 decade groups was estimated by a $x^2$ test. Result : The Korean beautiful woman skewed the geometric characteristics such as the 'coincidence' (83.0%) between facial midline and dental midline, the 'normal' (96.9%) alignment and arrangement of upper anterior teeth. the 'average' (79.1%) position and 'upward' (53.4%) curvature of upper lip, the 'parallel' (85.7%) relationship between the lower lip and upper anterior incisal curvature, the 'touching' (49.9%) and 'not-touching' (44.8%) relationship between upper anterior incisor and towel lip, the 'first premolar' (54.1%) and 'second premolar' (38.9%) displayed in a smile, and the 'symmetry' (89.4%) of smile. There was statistical significance among the 4 decades in the respect of the upper lip curvature, the relationship between upper anterior incisor and lower lip, and the most posterior teeth displayed in a smile (p<0.05). Conclusion : The Korean beautiful woman showed similar results to the western esthetic criteria in the some respects and the tendency that the Korean woman had more active smiling recently.