• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.347-354
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• 2012

The recovery force and displacement occur due to the phase transformation from the martensite phase to the austenite phase induced by the mechanical loading or thermal loading. These recovery force and displacement depend on an initial geometrical configuration of SMAs and loading conditions. Although the SMAs generally generates large recovery forces, the sufficient recovery displacement cannot be expected without a proper design strategy. The functionality of SMAs is limited due to the unbalance between the large recovery force and the small recovery displacement. This study suggests the double coil SMA spring in order to amplifying the recovery displacement induced by the phase transformation. By predicting the recovery displacement of doble coil SMA springs and one coil SMA springs induced by thermal loading, we show that the double coil SMA spring not only mitigate the unbalance of performance but also have a large recovery displacement for its recovery force than one coil SMA spring.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.04a
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• pp.25-33
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• 2002

Historical maps are precious materials, which show spatial distribution of land use, streets and so on at the time when the maps were produced. In analysis of historical maps, the most practical method is to compare them with the present ones, for instance by overlaying them. However, the low precision, in the geometrical sense, of the historical maps makes the task of comparison very difficult. This drawback brings us the idea to incorporate the historical maps into GIS after rubber-sheet transformation, i.e. geometric correction, of them. It makes comparing and overlaying multiple maps from different time periods. Furthermore, it gives map-scales to the historical maps, which are not in general represented on the old maps, and if we allow ourselves to ignore the changes in terrain from past to present, it will make overlaying of present contour lines on the historical maps. As a result, we can bring the points of view of quantitative consideration and three-dimensional visualization into analyses of historical map. We have addressed incorporating historical maps produced in Edo period (1603-1867) in Japan into our GIS for Tokyo. This article shows the outline of our procedures and some applications, e.g., overlaying different maps from Edo period to present, quantitative analyses of land use in Edo, and visualization of landscape of Edo.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.362-369
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• 2000

Via screw theory, a vibration mode can be geometrically interpreted as a pure rotation about the vibration center in a plane and as a twisting motion on a screw in a three dimensional space. In thi s paper, applying the conditions that can be used to diagonalize the stiffness matrix by a parallel axis congruence transformation, the vibration modes and frequency response of an elastically suspended optical disc drive have been analyzed. It is first shown that the system has one plane of symmetry, which enables one to decouple the complicated vibration modes into two sets of modes independent of each other. Having obtained the analytical solutions for the axes of vibrations, the frequency response for a given applied input force has been demonstrated. Most importantly, it has been explained that this research result could be used in the synthesis process of a linear vibration system in order to improve the frequency response.

• Korean Institute of Interior Design Journal
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• v.19 no.5
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• pp.83-94
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• 2010

Conventionally, ornament has developed around linear thinking based on Euclidean geometry, and been explained as simple and lucid natural Euclidean geometrical phenomena. The modular arrangement with vertical, horizontal and diagonal grids has been an organizing principle of classical ornament, but in digital era ornament is found not to be explained only with the principle of traditional arrangement due to the seemingly irregular complex forms. In that sense, this study presents the concept of digital ornament and examined the backgrounds of ornament in digital age, that are complex system and non-Euclidean geometry. Accordingly, the present study takes an approach by dividing new formal types of ornament into algorithmic form, hybrid form and dynamic form to find out a principle of pattern organization. Lately, architects who actively use computer for their architectural designs take the algorithmic strategies in nature and create various and complex patterns by simple rules. The patterns are not the repetition of the same, but the production of singularities. In addition, hybrid form by morphing shows a topologically flexible evolutionary transformation, and is used to create in-between transitional shapes from the source to target. Finally, the patterns by the interaction between the system components which are corresponded to the embedded forces emerge from dynamic simulation of the natural environment. Rather than objects itself, focus is given to the process of generating forms, and the ornamental patterns as the revelation of such implicit order provide not just the formal beauty but also spatial pathways for lights and air, maximizing the effects of lights.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.8
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• pp.961-968
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• 1999

In this paper we handle a system that transform sensor data to sensor information. Sensor informations from redundant accelerometers are manipulated to represent the configuration of objects carrying sensors. Basic sensor unit of the proposed systme is composed of 3 accelerometers that are aligned along x-y-z coordination axes of motion. To refine the sensor information, at first the sensor data are fused by geometrical optimization to reduce the variance of sensor information. To overcome the error caused from inexact alignment of each sensor to the coordination system, we propose a calibration technique that identifies the transformation between the coordinate axes and real sensor axes. The calibration technique make the sensor information approach real value. Also, we propose a technique that decomposes the accelerometer data into motion acceleration component and gravity acceleration component so that we can get more exact configuration of objects than in the case of raw sensor data. A set of experimental results are given to show the usefulness of the proposed method as well as the experiments in which the proposed techniques are applied to human body motion capture.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.328-336
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• 2012

In this paper, we propose a robust fingertip extraction and extended Continuously Adaptive Mean Shift (CAMSHIFT) based robust hand gesture recognition for natural human-like HRI (Human-Robot Interaction). Firstly, for efficient and rapid hand detection, the hand candidate regions are segmented by the combination with robust $YC_bC_r$ skin color model and haar-like features based adaboost. Using the extracted hand candidate regions, we estimate the palm region and fingertip position from distance transformation based voting and geometrical feature of hands. From the hand orientation and palm center position, we find the optimal fingertip position and its orientation. Then using extended CAMSHIFT, we reliably track the 2D hand gesture trajectory with extracted fingertip. Finally, we applied the conditional density propagation (CONDENSATION) to recognize the pre-defined temporal motion trajectories. Experimental results show that the proposed algorithm not only rapidly extracts the hand region with accurately extracted fingertip and its angle but also robustly tracks the hand under different illumination, size and rotation conditions. Using these results, we successfully recognize the multiple hand gestures.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.147-154
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• 2004

In this paper, Inverted Coordinates Image Space (ICIS) is proposed as a solution for the problem of the unbounded accumulator space in the automatic detection of the finite/infinite vanishing points in image space. Since the ICIS is based on the direct transformation from the image space, it does not lose any geometrical information from the original image and it does not require camera calibration as opposed to the Gaussian sphere based methods. Moreover, the proposed method can accurately detect both the finite and infinite vanishing points under a small fixed memory amount as opposed to the conventional image space based methods. Experiments are conducted on various real images in architectural environments to show the advantages of the proposed approach over conventional methods.

• Research in Mathematical Education
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• v.8 no.2
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• pp.107-114
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• 2004

University teachers of linear algebra often feel annoyed and disarmed when faced with the inability of their students to cope with concepts that they consider to be very simple. Usually, they lay the blame on the impossibility for the students to use geometrical intuition or the lack of practice in basic logic and set theory. J.-L. Dorier [(2002): Teaching Linear Algebra at University. In: T. Li (Ed.), Proceedings of the International Congress of Mathematicians (Beijing: August 20-28, 2002), Vol. III: Invited Lectures (pp. 875-884). Beijing: Higher Education Press] mentioned that the situation could not be improved substantially with the teaching of Cartesian geometry or/and logic and set theory prior to the linear algebra. In East Asian countries, science-orientated mathematics curricula of the high schools consist of calculus with many other materials. To understand differential and integral calculus efficiently or for other reasons, students have to learn a lot of content (and concepts) in linear algebra, such as ordered pairs, n-tuple numbers, planar and spatial coordinates, vectors, polynomials, matrices, etc., from an early age. The content of linear algebra is spread out from grades 7 to 12. When the high school teachers teach the content of linear algebra, however, they do not concern much about the concepts of content. With small effort, teachers can help the students to build concepts of vocabularies and languages of linear algebra.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.23-30
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• 2014

Feature matching using image descriptors is robust method used recently. However, mismatches occur in 3D transformed images, illumination-changed images and repetitive-pattern images. In this paper, we observe that there are a lot of mismatches in the images which have repetitive patterns. We analyze it and propose a method to eliminate these mismatches. MDMF(Multiple Descriptors-based Mismatch Filtering) eliminates mismatches by using descriptors of nearest several features of one specific feature point. In experiments, for geometrical transformation like scale, rotation, affine, we compare the match ratio among SIFT, ASIFT and MDMF, and we show that MDMF can eliminate mismatches successfully.

• The Research Journal of the Costume Culture
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• v.17 no.6
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• pp.972-980
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• 2009

This study was aimed to develop ume flower image into a competitive fashion culture product image by reinterpreting the image in modern terms, manufacturing patterns and applying them to various items. In terms of method, ume flower petal was used as a motive and developed into a pattern, using Adobe Illustrator 10, a computer design program. Based on the symbolic image and realist form of ume flower, three new basic motives of new figurative image were set using form omission, simplification, overlapping, repetition and graphic elements. Each motive developed transformed patterns through the change, transformation, combination of colors. The repetitive unit of each motive set expressed geometrical patterns and combination of flower patterns using pattern repetition and $45^{\circ}$ repetition technique in combination with the check arrangement using quadrangle, and set the direction of design that would fit for each item of fashion culture products. Also, consistency and practicality were sought in the goods planning composition of each item by applying motive pattern results to the fashion culture goods, such as neckties, scarves, T-shirts that can be consumed in everyday life. It seems that more creative culture goods including ume flowers will be developed by seeing our own cultural elements as well as flower patterns like ume flower with modern trends.