• Computers and Concrete
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• v.33 no.6
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• pp.671-688
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• 2024

The modeling efficiency of concrete meso-models close to real concrete is one of the important issues that limit the accuracy of mechanical simulation. In order to improve the modeling efficiency and the closeness of the numerical aggregate shape to the real aggregate, this paper proposes a method for generating a two-dimensional concrete meso-model based on pixel matrix and skeleton theory. First, initial concrete model (a container for placing aggregate) is generated using pixel matrix. Then, the skeleton curve of the residual space that is the model after excluding the existing aggregate is obtained using a thinning algorithm. Finally, the final model is obtained by placing the aggregate according to the curve branching points. Compared with the traditional Monte Carlo placement method, the proposed method greatly reduces the number of overlaps between aggregates by up to 95%, and the placement efficiency does not significantly decrease with increasing aggregate content. The model developed is close to the actual concrete experiments in terms of aggregate gradation, aspect ratio, asymmetry, concavity and convexity, and old-new mortar ratio, cracking form, and stress-strain curve. In addition, the cracking loss process of concrete under uniaxial compression was explained at the mesoscale.

• Journal of the Korea Computer Graphics Society
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• v.24 no.3
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• pp.33-41
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• 2018

We present a secondary camera optimization method that helps the user exploring 3D virtual environment to precisely observe possible collisions between objects. The first role of our secondary camera is to automatically detect the area with the greatest possible collision. The second role is to show the detected area from a new angle of view that the current main camera cannot show. However, as the shapes of target objects are complex, the shape of the empty space between objects is also complex and narrow. It means that the space for the secondary camera position is highly constrained and its optimization can be very difficult. To avoid this difficulty and increase the efficiency of the optimization, we first compute a bisector surface between two target objects. Then, we limit the domain of the secondary camera's position on the bisector surface in the optimization process. To verify the utility of our method, we built a demonstration program in which the user can explore in a 3D virtual world and interact with objects by using a hand motion recognition device and conducted a user study.

• The korean journal of orthodontics
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• v.37 no.6
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• pp.407-420
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• 2007

The aim of this study was to compare the differences in closing extraction spaces between maxillary first premolar and second premolar extractions using 3-dimensional finite element analysis (FEA). Methods: Maxillary artificial teeth were selected according to Wheeler's dental anatomy. The size and shape of each tooth, bracket and archwire were made from captured real images by a 3D laser scanner and FEA was performed with a 10-noded tetrahedron. A $10^{\circ}$ gable bend was placed behind the bull loop on a $0.017"{\times}0.025"$ archwire. The extraction space was then closed through 12 repeated activating processes for each 2mm of space. Results and Conclusions: The study demonstrated that the retraction of anterior teeth was less for the second premolar extraction than for the first premolar extraction. The anterior teeth showed a controlled tipping movement with slight extrusion, and the posterior teeth showed a mesial-in rotational movement. For the second premolar extraction, buccal movement of posterior teeth was highly increased.

• Korean Journal of Animal Reproduction
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• v.16 no.1
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• pp.21-38
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• 1992

The present study was carried out to investigate morphologic changes in the corpus luteum of the pregnant rat by electron microscope after administration of prostaglandin F2$\alpha$(PGF2$\alpha$). Pregnant rates were treated with PGF2$\alpha$(1,500$\mu\textrm{g}$/rat) and their corpura lutea were observed morphologically. The results obtained in this study were summarized as follows ; 1. The weight of the ovaries and corpura lutea were decreased slightly at 8~24 hours after PGF2$\alpha$ administratin but no significant differences were observed. 2. The number of corpora lutea and luteal cells decreased slightly at 12~48 hours and 18~24 hours after PGF2$\alpha$ tretment but there were no signifciant differences between control and treatment. 3. The weight of uterus and the unmber of embryo decreased slightly at 96 hours and at 18~96 hours after PGF2$\alpha$ administration but no significant differences were obtained. 4. In the electron microscopic observatons, lipid droplets which are electron dense and appear in the cytoplasm moderately increased in number after PGF2$\alpha$ treatment. The lipid droplets were surrounded by mitochodria and appeared in the autophagic vacuoles. 5. Moderated and high electron dense mitochondria which are round or elongated in shape showed pleomorphism from 3 hours after PGF2$\alpha$ treatment. Destruction of tubular of vesicular cristae was observed at 6 hours after the treatment. Dense body and myelin figures in matrix of mitochondria were also appeared. 6. Well-developed smooth endoplasmic reticulum(sER) showed tubular or vesicular cisternae. A number of whorl membranes containing ribosomes, mitochondria and lipid droplets were observed at 1.5 hour after treatment. sER was abundant in luteal cells at 12 hours were treatment. 7. Well-developed Golgi pparatus appeared obviously 6 hours and more prominently at 12 hours. Those Golgi vesicles were remarkably dilated. 8. Generally, a few rough endoplasmic reticulum (rER) were appeared after treatment and cisternae showed slight dilatation. No differences among the treatments were observed. However, slight dilation of cisternae was observed at 1.5 hours after treatment. 9. Ribosomes composed of free and polyribosomes were abundant before treatment but polyribosomes were appeared at 12 to 24 hours after treatment. 10. Intercellular space were slightly extended at 3 hours and markedly extended at 12 hours. Numerous microvillous protrusions were observed at these times. Membranous multivesicular structures and autophagic vacuoles were also appeared in the intercellular space. 11. At 3 hours after the treatment, autophagic vacuoles appeared in the cytoplasm of the cell. They increased in number with time and were observed to transfer to the intercellular space. Lysosomal dense body appeared in the cytoplasm and the inclusion body was also observed in nucleus at 12 to 24 hours after treatment.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.4
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• pp.375-384
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• 2005

Three dimensional urban models are being increasingly applied for various purposes such as city planning, telecommunication cell planning, traffic analysis, environmental monitoring and disaster management. In recent years, technologies from CAD and GIS are being merged to find optimal solutions in three dimensional modeling of urban buildings. These solutions include modeling of the interior building space as well as its exterior shape visualization. Research and development effort in this area has been performed by scientists and engineers from Computer Graphics, CAD and GIS. Computer Graphics and CAD focussed on precise and efficient visualization, where as GIS emphasized on topology and spatial analysis. Complementary research effort is required for an effective model to serve both visualization and spatial analysis purposes. This study presents an efficient way of using the CAD plans included in the building register documents to reconstruct the internal space of buildings. Topological information was built in the geospatial database and merged with the geometric information of CAD plans. as well as other attributal data from the building register. The GIS network modeling method introduced in this study is expected to enable an effective 3 dimensional spatial analysis of building interior which is developing with increasing complexity and size.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.2 s.115
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• pp.80-98
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• 2006

This study originated from following questions. What can we understand the conception of deconstruction, which has been the core idea of new discourses developed in various ways since modernism? How can this question be interpreted in landscape design? What is the conceptional frame of integration the prominent hybrid post-genre movements and phenomena? The frame can be epitomized with the deconstruction phenomenon. 'Deconstruction' is the core conception appeared in late or post-modern ages in the embodiment of modernity and can be viewed as an integrating or a hybrid phenomenon between areas or genres in formative arts. Therefore, the author regards the hybrid movements widely witnessed in the post contemporary formative arts as one of the most important indicators of de-constructive signs. It is safe to say that the phenomenon of this integration or hybridism, of course, does not threaten the identity of landscape design but serves as an opportunity to extend the areas of landscape design. One of the consequences of this integration or hybridism is the voluntary participation of users who have been alienated in the production of the meanings of design works and hybrid landscape design with the hybridization of genres that is characterized with transformation in forms. This view is based on the distinction between hybridization of interactions between the designer (the subject) and the user (the object), and hybridization of synesthesia. Generally speaking, this is an act of destroying boundaries of the daily life and arts. At the same time, it corresponds to vanishing of modern aesthetics and emerging of post-contemporary aesthetics which is a new aesthetic category like sublimeness. This types of landscape design tries to restore humans' sensibility and perceptions restrained by rationality and recognition in previous approach and to express non-materialistic characteristics with precaution against excessive materialism in the modern era. In light of these backgrounds, the study aims to suggest the hybrid concept and to explorer a new landscape design approach with this concept, in order to change the design structure from 'completed' or 'closed' toward 'opened' and to understand the characteristics of interactions between users and designs. This new approach is expected to create an open-space integrating complexity and dynamics of users. At the same time, it emphasizes senses of user' body with synesthesia and non-determination. The focus is placed on user participation and sublimity rather than on aesthetic beauty, which kind of experience is called simulacre. By attaching importance to user participation, the work got free from the material characteristics, and acceptance from the old practice of simple perception and contemplation. The boundaries between the subject and object and the beautiful and ordinary, from the perspective of this approach, are vanished. Now everything ordinary can become an artistic work. Western dichotomy and discrimination is not effective any more. And there is 'de-construction' where there is perfect equality between ordinary daily life and beautiful arts. Thus today's landscape design pays attention to the user and uses newly perceived sensitivity by pursing obscure and unfamiliar things rather than aesthetic beauty. Space is accordingly defined to take place accidentally as happening and event, not as volume of shape. It's the true way to express spatiality of landscape design. That's an attempt to reject conventional concepts about forms and space, which served as the basis for landscape design, and to search for new things.

• Journal of Korean Library and Information Science Society
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• v.48 no.2
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• pp.73-97
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• 2017

School Library is both a space and a place. The difference between space and place is the same as in the difference between house and home. Space may be described in terms of physical shape. Place is concept that formulated by personal experience. The social and cognitive developmental stages of elementary, middle and high school students are different, so the placeness or sense of place may be different. The purpose of this study is to figure out the differences in elementary and secondary school student's formative factors of placeness and examine the process that those factors are connected to the results of the user behavioral intentions through the medium of place attachment, place value perception. The data are collected from 590 students and analyzed by SPSS 19 and AMOS 19. The results of this study are as follows. The physical, active behavioral and psychological factors affect on placeness formation of elementary and secondary school students in school libraries. Elementary school students are significantly affected more by physical factors, active behavioral factors than middle and high school students. This study confirmed the process that those factors are connected to the results of the user behavior through the medium of place attachment, place value perception.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.6
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• pp.637-652
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• 2012

The protector with the shape of '${\sqcap}$' in cross section can be set up in the tunnel, which can be constructed for enlargement of cross section, to keep traffic flow in the tunnel. It is impossible to install the rockbolt in the side wall of tunnel due to a limited space between the protector and cutting surface of side wall. The objective of this study is to suggest the optimum thickness of shotcrete lining without rockbolt on the side wall and to evaluate the stability of tunnel enlarged. Numerical analysis was performed to evaluate the displacement at the center of tunnel, the convergence of tunnel, and the stress in shotcrete lining in 4-lane NATM road tunnel enlarged from 3-lane NATM road tunnel. The vertical displacement at the center of tunnel and the convergence of crown in the tunnel with rockbolt in the side wall were almost similar to those in the tunnel without rockbolt in the side wall. The convergence of bench/invert and the stress in shotcrete lining without rockbolt on the side wall were greater maximum 0.57 mm and 1,300 kN/$m^2$ than those with rockbolt in the side wall. The increased convergence and the stress in shotcrete lining can be reduced in incerasing of thickness of shotcrete lining about 20% (5 cm) of standard thickness, 25 cm, of shotcrete lining.

• Journal of Veterinary Clinics
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• v.11 no.2
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• pp.529-537
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• 1994

Sector scanner which has a conical end is used to image through the intercostal space because heart is protected by the ribs. Cardiac data published all around the world were also obtained by sector scanner. Although scanners being used in every small animal practice and animal hospital at college in Korea include convex ape and linear type, linear type is not appropriate f3r cardiac scan because of a wide contact surface. The purpose of this study is to establish ultrasonographic images of normal cardiac structures by measuring shape, size of reflectable cardiac structure according to restraint position in scanning normal heart of the puppies with 6.5 MHz convex scanner(SonoAce 4500, Medison, Korea) used in our veterinary teaching hospital, Seoul national university. Seventeen male and female puppies considered having healthy hear by X-ray and clinical examination are used feom April to July 1994. Scanning point selection of probe head and the distinction of imaged cardiac structures were accomplished by necropsy and cardiac scanning performed through thoracotomy under general anesthesia. At 10 o'clock position of transducer(at an angle of 30$^{\circ}$ between imaginary line from elbow joint to 3rd sternum and probe head, 60$^{\circ}$ from body surface, 4th intercostal space of right thorax) with the marker of scanner toward the head of dogs right atrium, left atrium and left ventricle were observed in 2, 3, 4, 5 intercostal space(2cm from the sternum) of experimental dog positioned ventrodorsally under general anesthesia. Under these conditions, the numerical values of imaged diastolic hear are as follows : the distance from skin to apex(mean$\pm$S.D) 47.53$\pm$6.94mm, thickness of left ventricular wall 6.00$\pm$1.60mm, length of left ventricle 16.27$\pm$5.31mm, width of left ventricle 15,33$\pm$4.25mm, length of left atrium 12.33$\pm$3.82mm, width of left atrium 11. 33$\pm$3.94mm, length of right atrium 1.00$\pm$2.41mm, width of right atrium 11.21$\pm$2.76mm and the area of left ventricle 270.92$\pm$109.81mm$^2$, area of left atrium 98.00$\pm$41.08mm$^2$, area of right atrium 62.75$\pm$21.04mm$^2$.

• The Research Journal of the Costume Culture
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• v.18 no.2
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• pp.261-276
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• 2010

The analysis of an art trend in the principle dimension starts by observing the object of work in the perspective of formative composition and recognizing it as a universal system. It can be said that it is consistent with an interpretation method for a form theory of formal history by Heinrich W$\ddot{o}$lfflin, a leading form critic in art criticism. Hence, the purpose of this study was to find out what are the formative principles in Renaissance Classicism as a design principle to be applicable to modern fashion by reviewing the formative characteristics of Renaissance Classicism Architecture with which W$\ddot{o}$lfflin directly dealt. As for the theoretical literature review, I used W$\ddot{o}$lfflin's theoretical framework and looked at the Renaissance Classicism Architecture that he studied and examined the possibility of utilizing his theory as a layout principle and the characteristics. As for analysis of design cases, I applied the aforementioned architecture layout principle to modern fashion and conducted case study analysis to delve into distinctive layout principles found in fashion. The study showed that the Renaissance Classicism Architectural Style is marked by linearity, planarity, closing and multiple unity: linearity was expressed in the observation form in fixed frontal view and an emphasis on a tangible silhouette homeogenous and definite line structures; planarity was achieved in the form of paralleled layers of frontal view element, planarity style, and identical and proportional repetition of various sizes.; closing signified the pursuit of complete and clear regularity, and architecture developed in a constructive phase through organizational inevitability and absolute invariability.; multiple unity was expressed in self-completedness and independent parallel of discrete forms and harmony of emphasized individual elements in a totality. Applying these layout characteristics of the Renaissance Classicism Architectural style and to see their individual expressive features, I found out that in adopting layout principles of the Renaissance Classicism Architecture to modern fashion, it turned out to be an emphasis of individual silhouettes, a flattened space, completed objects, organic harmony among independent parts: the emphasis of individual silhouettes was expressed in individual definitiveness of formative lines of clothes in accordance with body joints and an emphasis on formative lines of clothes; the flattened space was marked by single layer structure, planarity of elements of clothes, and listing arrangement by appropriate proportion.; the completedness of the objects was expressed by the stationary state where overall image is fixed, the construction of homogeneous and complete space, and absolute inevitability of internal layout in proportion; lastly, organic harmony of independent parts was stressed in independent completedness of each detail, and organic harmony of the whole. The expressive features would lead to a unique expression style of linear emphasis, proportion, constructive forms, and two-dimensional arrangement. The meaning of this study is follows: The characteristics of art school of thought are given shape by appling & analysing the architectural layout principles of historical art school of thought to modern fashion in the view point of formal construction dimension. The applied possibility of historical art school of thought as the source of inspiration about the fashion design is extended.