• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2092-2095
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• 2001

In this paper, the performance of a new alternative form of three-axis attitude estimation algorithm for a rigid body is evaluated via simulation for the situation where the observed vectors are the estimated baselines of a GPS antenna array. This method is derived based on a simple iterative nonlinear least-squares with four elements of quaternion parameter. The representation of quaternion parameters for three-axis attitude of a rigid body is free from singularity problem. The performance of the proposed algorithm is compared with other eight existing methods, such as, Transformation Method (TM), Vector Observation Method (VOM), TRIAD algorithm, two versions of QUaternion ESTimator (QUEST), Singular Value Decomposition (SVD) method, Fast Optimal Attitude Matrix (FOAM), Slower Optimal Matrix Algorithm (SOMA).

• Wind and Structures
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• v.34 no.1
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• pp.1-14
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• 2022

In this work the flow through a hollow porous 5:1 rectangular cylinder made of perforated plates is numerically investigated by means of 2D URANS based simulations. Two approaches are adopted to account for the porous surfaces: in the first one the pores are explicitly modeled, so providing a detailed representation of the flow. In the second one, the porous surfaces are modeled by means of pressure jumps, which allow to take into account the presence of pores without reproducing the flow details. Results obtained by using the two aforementioned techniques are compared aiming at evaluating differences and similarities, as well as identifying the main flow features which might cause discrepancies. Results show that, even in the case of pores remarkably smaller than the immersed body, their arrangement can lead to local mechanisms able to affect the global flow arrangement, so limiting the accuracy of pressure jumps based simulations. Despite that, time-averaged fields often show a reasonable agreement between the two approaches.

• The Journal of the Korea Contents Association
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• v.5 no.4
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• pp.122-132
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• 2005

CVE(Collaborative Virtual Environment) is the virtually shared area where people cannot come together physically, but wish to discuss, collaborate on, or even dispute certain matters. In CVEs, in habitants are usually represented by humanoid embodiments, generally referred to as avatars. But most current graphical CVE systems fail to reflect the natural relationship between the avatar's gesture and the conversation that is taking place. More than 65% of the information exchanged during a person to person conversation is carried on the nonverbal band. Therefore, it is expected to be beneficial to provide such communication channels in CVEs in some way. To address this issue, this study proposes a scheme to represent avatar's gestures that can support the CVE users' communication. In the first level, this study classifies the non-verbal communication forms that can be applicable to avatar gesture design. In the second level, this study categorizes the body language according to the types of interaction with verbal language. And in the third level, this study examines gestures with relevant verbal expressions according to the body parts-from head to feet. One bodily gesture can be analyzed in the description of gesture representation, the meaning of gesture and the possible expressions, which can be used in gestural situation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.3
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• pp.248-257
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• 2011

In the present study, we proposed a new numerical wave tank model to analyze the vertical tension-leg circular floating bodies, using a 2-D Navier-Stokes solver. An IBM(Immersed Boundary Method) capable of handling interactions between waves and moving structures with complex geometry on a standard regular Cartesian grid system is coupled to the VOF(Volume of Fluid) method for tracking the free surface. Present numerical results for the motions of the floating body were compared with existing experimental data as well as numerical results based on FAVOR(Fractional Area Volume Obstacle Representation) algorithm. For detailed examinations of the present model, the additional hydraulic experiments for floating motions and free surface transformations were conducted. Further, the versatility of the proposed numerical model was verified via the numerical and physical experiments for the general rectangular floating bodies. Numerical results were compared with experiments and good agreement was archived.

• Korean Journal of Human Ecology
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• v.11 no.3
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• pp.287-299
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• 2002

Post-modernism exists with different shapes in overall cultural phenomena. Among the creative methods of composing post-modernism, there are representation, parody, plural coding, trans avant-garde etc. Summing up the influence of creative method of post-modernism on modem fashion led to the following results. 1. The phenomenon appears that value and valuelessness are easily reversed, and things with historical and traditional meanings are being ignored. 2. The boundary between higher culture and public culture is being disorganized, and mixed imitation phenomenon ignoring the differences between male and female is emerging 3. The mental and historial aspects in fashion pattern are highly thought of and the trend to understand human body from the various angles emerges. 4. In the consumer-oriented society, it appears in the form of meanings to achieve the self-achievement in individual life, to express one's idea and desire in the esthetical point of views. 5. It shows that through arranging the striking things and the distorted things, it takes the compromised method of re-appreciating the existing ideas. The phenomena in the post-modernism occurring in fashion design forced the concept of the uniformed existing fashion to be changed, creating a various fashions. That can just be called the dehumanization trend in the era of post-modernism, which is the most important formative feature in modern fashion.

• Journal of information and communication convergence engineering
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• v.11 no.2
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• pp.124-131
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• 2013

Extraction and representation of postures and/or gestures from human activities in videos have been a focus of research in this area of action recognition. With various applications cropping up from different fields, this paper seeks to improve the performance of these action recognition machines by proposing a shape-based silhouette-edge descriptor for the human body. Information entropy, a method to measure the randomness of a sequence of symbols, is used to aid the selection of vital key postures from video frames. Morphological operations are applied to extract and stack edges to uniquely represent different actions shape-wise. To classify an action from a new input video, a Hausdorff distance measure is applied between the gallery representations and the query images formed from the proposed procedure. The method is tested on known public databases for its validation. An effective method of human action annotation and description has been effectively achieved.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.500-507
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• 2022

In this study, a motion planning method based on the integer representation of contact status between wheels and the ground is proposed for planning swing motion of a 6×6 wheel-legged robot to cross large obstacles and gaps. Wheel-legged robots can drive on a flat road by wheels and overcome large obstacles by legs. Autonomously crossing large obstacles requires the robot to perform complex motion planning of multi-contacts and wheel-rolling at the same time. The lift-off and touch-down status of wheels and the trajectories of legs should be carefully planned to avoid collision between the robot body and the obstacle. To address this issue, we propose a planning method for swing motion of robot legs. It combines an integer representation of discrete contact status and a trajectory optimization based on the direct collocation method, which results in a mixed-integer nonlinear programming (MINLP) problem. The planned motion is used to control the joint angles of the articulated legs. The proposed method is verified by the MuJoCo simulation and shows that over 95% and 83% success rate when the height of vertical obstacles and the length of gaps are equal to or less than 1.68 times of the wheel radius and 1.44 times of the wheel diameter, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.107-116
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• 1993

In the design and operation of robitic arm with flexible links, the equation of motion are required to exactly model the interaction between rigid body motion and elastic motion and to be formulated efficientlyl. In this paper, the flexible link is represented by applying the D-H rigid link representation method to measure the elestic deformation. And the equations of motion of robotic arm, which are configured by the generalized coordinates of elastic and rigid degrees of freedom, are formulated from the principle of virtual power. Dynamic characteristics due to elastic deformation of each link are obtained by using F. E. M to model complex shaped link acurately and by eliminating elastic modes of higher order that do not largely affect motion to reduce the number of elastic degrees of freedom. Also presented is the result of simulation of flexible robotic arms whose joints are controlled by direct or PD control.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.1067-1075
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• 2006

This paper proposes a advanced representation method of hand motion by cheremes analysis in korean sign language. The proposed method is the representation method which apply to the hand motion used in KSL(Korean Sign Language) to represent rich and united hand motion. Words or sentences in KSL are completed by combination of elements called as Cheremes, that is, a hand movement orientation, a finger shape, a hand position, etc. In this paper, Cheremes composing the KSL is divided and represented by 5 elements: the hand movement orientation(HMO), finger shape(FS), hand orientation(HO), hand position(HP) and number of using hand (HN). Each cheremes is expressed by more various characteristics. For example, The hand movement orientation means orientations which the hand move while the sign language is done and can be expressed by 17orientation components. The finger shape means various shapes which fingers can take and represented by 17 components. The Orientation of hand is expressed by 2 characteristics according to whether we use the palm of the hand or the back. The position of hand means specific regions in body which hand(s) is placed while the sign language is done and divided by 8 regions. Finally, the number of hand means whether use only one hand or both hands and is expressed by 2 characteristics. The proposed method has been tested with KSL words and sentences and the results have shown that they can be expressed completely by the proposed representation method.

• The Research Journal of the Costume Culture
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• v.19 no.4
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• pp.805-819
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• 2011

In contemporary society, heterotopia is the law dominates thoughts and is the concept reconstituted spaces calls order in chaos. And that is the place which refuses the paradoxical and social custom and sometimes poses a danger and rise in rebel. The purpose of this study is to study how forms of clothing fluid form images are expressed in modern fashion develop body around in the spatial relationship between the body and its environment. The study method consider changed characterastics of fluid space through the heterotopia thinking system of Foucault Michel. Based on this method, the heterotopia space that appeared in the plastic arts in aspects of artistic significance and aesthetic value was examined. Based on the above discussion on modern fashion Fluid Form were expressed in any formative characteristics were considered. The results of this study are as follows. Fluidity is the transformed interaction. It expanded external representation of organic body structure and reconstructed flexible forms of dynamic structures continuously. Transformation is the new space structure. It constructed invisible transformation and developed convertible dress space by combining a variety of functional overlap and fold. Deconstruction was expressed structural forms, expanding the existing forms in the open structure which have ambiguous boundaries.