• Journal of the Korean Society for Precision Engineering
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• v.14 no.7
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• pp.144-153
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• 1997

The inverse kinematics problem of a reclaimer which excavates and transports raw materials in a raw yard is investigated. Because of the geometric feature of the equipment in which scooping buckets are attached around the rotating disk, kinematic redundancy occurs in determining joint variable. Link coordinates are introduced following the Denavit-Hartenbery representation. For a given excavation point the forward kinematics yields 3 equations, however the number of involved joint variables in the equations is four. It is shown that the rotating disk at the end of the boom provides an extra passive degree of freedom. Two approaches are investigated in obtaining inverse kinematics solutions. The first method pre-assigns the height of excavation point which can be determined through path planning. A closed form solution is obtained for the first approach. The second method exploits the orthogonality between the normal vector at the excavation point and the z axis of the end-effector coordinate system. The geometry near the reclaiming point has been approximated as a plane, and the plane equation has been obtained by the least square method considering 8 adjacent points near the point. A closed form solution is not found for the second approach, however a linear approximate solution is provided.

• Journal of the Korea Furniture Society
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• v.26 no.4
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• pp.314-327
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• 2015

20th century, beginning of modern, the style of art and design, separated reasonable and sensitive code. Art form including cubism, constructivism, futurism and different form including fauvism, expressionism, surrealism and abstract expressionism coexist two code in early modern. But the style of design was separated each period with geometric and organic form, reasonable and sensitive code. Replacement timing on two design style was the transition period of the production-oriented step to the sale-oriented step in marketing. In early stage modern it was stable production-oriented step. Geometric style include G. Rietvevld (Red and Blue chair), M. Breuer (Wassily chair), Fanizon and Martinelli (I-Ching) was simple and functional, received the absolute support. An aggressive demand generation and sales promotion for the design change was needed so that excess supply in the market with a stable production. In sale-oriented step for sales promotion in mid modernism, it was accepted transitions to the sensual organic volume with elegant and sleek style include C. Eames (LCW chair), V. Panton (Panton chair) and C. Mollino (Arabesco Tea table).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.325-328
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• 2011

In this paper, we present a new and simple derivation of the Craig representation for the two-dimensional (2-D) Gaussian Q-function in the viewpoint of geometry. The geometric derivation also leads to an alternative Craig form for the 2-D Gaussian Q-function. The derived Craig form is newly obtained from the geometry of two wedge-shaped regions generated by the rotation of Cartesian coordinates over two correlated Gaussian noises. The presented Craig form can play a important role in computing the probability represented by the 2-D Gaussian Q-function.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.52-59
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• 2009

In the study will look into how Baroque concepts are expressed in architectural space by analyzing the concepts of Baroque formative vocabularies applied in his architecture through a Spanish architect Paolo Portoghesi. Baroque is regarded as the philosophical thought that means enlargement toward diversity of a firm and fixed trend beyond the concept of a certain epochal form of 16th and 17th century architecture. In addition, it is from the free attitude and the intelligent and formal stereotype, and signifies common conditions more than one style in architecture history. Paolo Portoghesi proposes to express gestalt approach by Baroque precedent in his architecture through plasticity and geometric collision technique. Here, the expression of plasticity means the effect that gives formative rhythm to Baroque curved structures. That is the method to expand the formative possibility by changing various materials such as bricks, concrete, and timbers. Second, the geometric collision technique is the technique to constitute the flat form of overall space through the juxtaposition technique, Baroque symmetrical and homogeneous geometric manipulation technique. Accordingly, this study will overcome Inlimitation of formative monotony and expression of abstraction that modernism architecture has, and examine formative waste and conflicts which may be derived from impractical architectural languages of the concept of excessive disorder or the minimum form. This discussion is considered as the first step to tune balance between productivity and formativeness in modern architecture.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.237-242
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• 2001

In this paper, we theoretically analyzed the NRRO(the non-repeatable run-out) of a ball bearing with ball geometric imperfection. The quasi-static and dynamic analysis of a ball bearing was performed to calculate the displacement of shaft center caused by the ball form errors while the shaft is rotating. From consideration of the generating mechanism of NRRO, it is found that the size and form errors of ball generate vibrations with (equation omitted)$\_$c/ and n(equation omitted)$\_$b/${\pm}$(equation omitted)$\_$c/(where n is even) components, respectively. The ball form errors of a ball bearing were precisely measured and NRRO of a ball bearing was calculated using the measured data. A statistical approach was peformed to analyze NRRO of ball bearings with radial errors.

• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.121-144
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• 2005

In this paper, we propose unconstrained and constrained posynomial Geometric Programming (GP) problem with negative or positive integral degree of difficulty. Conventional GP approach has been modified to solve some special type of GP problems. In specific case, when the degree of difficulty is negative, the normality and the orthogonality conditions of the dual program give a system of linear equations. No general solution vector exists for this system of linear equations. But an approximate solution can be determined by the least square and also max-min method. Here, modified form of geometric programming method has been demonstrated and for that purpose necessary theorems have been derived. Finally, these are illustrated by numerical examples and applications.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.6
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• pp.30-36
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• 2003

To improve survivability of damaged ship, assessment of stability and structural safety, and behavior analysis in wave is required. Prediction of sinking time, damage stability and structural strength considering progressive flooding and dynamic force in wave is very important. To do it, a geometric model which can be express damaged ship is prepared. This paper described the geometric modeler for survivability assessment of damaged ship. The modeler is developed based on 3-D geometric modeling kernel, ACIS. The hull form and compartment definition is available fundamentally. And requirement for modeler contains data generation and interface for hydrostatic calculation, behavior analysis, and longitudinal strength analysis and so on. To easy access modeling system by conventional user such as crew, user interface is developing.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.12 s.148
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• pp.1582-1594
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• 2005

The purpose of this study is to rediscover the value of form in fashion design by developing a new perspective of design appreciation. By examining and modifying the theories of Wolfflin and Belong, this paper tries to of for a new perspective for analyzing the characteristics of form in fashion designers' works. The three new perspective, Flat & Rounded, Closed & Opened and Part & Whole, can be used to analyze the formative aesthetic character of Vionnet's and Dior's works. Ten of Vionnet's and eleven of Dior's representative works selected and applied Delong's visual priority diagram to analyze their character. Vionnet and Dior, emphasized form and construction in their design and applied geometric shapes in their works. The main differences between Vionnet and Dior is that Vionnet's work transforms from geometric shapes in 2-dimentional space to drapery shapes in 3-dimensional space, Dior's work displays geometric shapes in 3-dimensional space. Vionnet created new formative art through the relationship between the clothes and human body. Vionnet's work has distinctively different qualities depending on whether the space is 2-dimensional or 3-dimensional showing transposition of form. In 2-dimensional space, Vionnet's works consist of triangles, rectangles and circles which are 'flat' and 'closed' in quality. These transform to solid forms by draping bias fabrics, which have a 'rounded' and 'open' quality. Dior tended to show artificial form rather than the natural lines of the body which is very different with Vionnet. Dior created clothes by using solid geometric form such as spheres, prisms, cylinders, pyramids and cubes in 3-dimensional space, which were visualized through constructive technique such as dart manipulation, boning, gathering, tucking, pleating, shirring and layering. Dior's works have their own form which does not relate with body shape. So his Works have a 'rounded' and 'closed' quality.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.1-7
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• 2013

This paper aims at contributing to the field of ship design by introducing new systematic variation methods for ship hull forms. Hull form design is generally carried out in two stages. The first is the global variation considering the sectional area curve. Because the geometric properties of a sectional area curve have a decisive effect on the global hydrodynamic properties of ships, the design of a sectional area curve that satisfies various global design conditions, e.g., the displacement, longitudinal center of buoyancy, etc., is important in the initial hull form design stage. The second stage involves the local design of section forms. Section forms affect the local hydrodynamic properties, e.g., the local pressure in the fore- and aftbody. This paper deals with a new method for the systematic variation of sectional area curves. The longitudinal volume distribution of a ship depends on the sectional area curve, which can geometrically be controlled using parametric variation and a variation that uses the modification function. Based on these methods, we suggest a more generalized method in connection with the derivation of the lines for a new design compared to those for similar ships. This is the so-called the volumetric balanced variation (VOB) method for ship forms using a B-spline modification function and an optimization technique. In this paper the global geometric properties of hull forms are totally controlled by the form parameters. We describe the new method and some application examples in detail.

• The Journal of Art Theory & Practice
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• no.9
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• pp.151-170
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• 2010

As an art group, De Stijl (1917-1931) led a total art movement encompassing painting, sculpture, design, and architecture. Among these, architecture, as a model of the total art pursued by the group, was encapsulated by the term 'plastic architecture.' The term reflects architecture's shared features with plastic art, especially its pictorial characteristics. Firstly, De Stijl architecture shares geometric form with painting. Assembled in simple, clear and rational structures, the geometric forms signified universal forms, and extended the pictorial experimentation that Mondrian exercised through Neo-Plasticism to architecture. Constructed with colour fields made of concrete wall, De Stijl architecture is geometric abstract painting embodied in space. Together with such pictorial characteristics, large plate glass windows, narrow window frames, and cantilever structure minimize the building's visual weight. De Stijl architecture, which appears suspended in the air, is an architectural version of the abstract paintings of the era that revealed unknown spaces beyond perspective. De Stijl architecture is also an 'open' architecture, where the units placed as if radiating from the center form relations with each other flexibly and organically. The observer in such a space is encouraged to experience space within time, as his/her physical and visual mobility and extension are maximized. De Stijl architecture is an example of how the time-space continuum, represented within picture frame through Cubism, Futurism, and abstract art, can be realized in space. By transforming the ideal space of painting into real space in this way, 'plastic architecture' turned out to be an architectural manifestation of the utopianism of the era, aimed at building a society in 'perfect harmony.' However, such rationalism and universalism are not free from the violence of totalization that deletes various differences. This is evident in the history that followed as the geometric form of architecture and urban planning proliferated across the globe, engulfing the diverse natural landscapes and local cultures.