• Journal of Computing Science and Engineering
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• v.12 no.1
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• pp.1-11
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• 2018

Human activities recognition is a challenging task due to its complexity of human movements and the variety performed by different subjects for the same action. This paper presents a recognition algorithm by using skeleton information generated from depth maps. Concatenating motion features and temporal constraint feature produces feature vector. Reducing dictionary scale proposes an improved fast classifier based on sparse representation. The developed method is shown to be effective by recognizing different activities on the UTD-MHAD dataset. Comparison results indicate superior performance of our method over some existing methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.764-767
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• 2009

Motion capture systems allow to measure the precise position of markers on the human body in real time. These captured motion data, the marker position data, have to be fitted by a human skeleton model to represent the motion of the human. Typical human skeleton models approximate the joints using a ball joint model. However, because this model cannot represent the human skeleton precisely, errors between the motion data and the movements of the simplified human skeleton model happen. We propose in this paper a method for measuring a translation component of wrist, and elbow joints on upper limb using optical motion capture system. Then we study the errors between the ball joint model and acquired motion data. In addition, we discuss the problem to estimate motion of human joint using optical motion capture system.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.451-459
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• 2019

This study is aims to examine how the skeleton character in Pixar's Animation is visualized for the narrative of the film and suggests the direction of attractive character development corresponding to the story. First of all, it was conducted the case studies on the narrative of animation, character design, character's emotion expression, and animations featuring skeleton character. Based on this study, it was derived the visual representation of the skeleton character featuring in and analyzed the role and function in the animation. As a result, the expressions by the skeleton's eyes, eyebrows, mouth, lips, and jaw played the most important role for the emotional expression and lines in , and the major characteristic for human facial expression was reflected in the design of the skeleton character. In addition, the various props were used to provide the detailed informations of the skeleton's character, and it was expressed the movement emphasizing its essential attribute. Finally, the skeleton's symbolic image was strengthened by composing and arranging the skeleton's image through Mise en scene. It is expected that this study will be used as a reference for the animation character related researchers and practitioners in the business and it helps develop attractive characters fir the narrative animation in the future.

• ETRI Journal
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• v.29 no.4
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• pp.507-515
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• 2007

Skeleton transform of which the medial axis transform is the most popular has been proposed as a useful shape abstraction tool for the representation and modeling of human posture. This paper explains this proposition with a description of the areas in which skeletons could serve to enable the representation of shapes. We present algorithms for two-dimensional posture modeling using the developed simplified shock graph (SSG). The efficacy of SSG extracted feature vectors as shape descriptors are also evaluated using three different classifiers, namely, decision tree, multilayer perceptron, and support vector machine. The paper concludes with a discussion of the issues involved in using shock graphs to model and classify human postures.

• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.165-181
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• 2009

This paper presents an effective representation scheme for the shape analysis of the hippocampal structure and a stereoscopic-haptic environment to enhance sense of realism. The parametric model and the 3D skeleton represent various types of hippocampal shapes and they are stored in the Octree data structure. So they can be used for the interactive shape analysis. And the 3D skeleton-based pose normalization allows us to align a position and an orientation of the 3D hippocampal models constructed from multimodal medical imaging data. We also have trained Support Vector Machine (SVM) for classifying between the normal controls and epileptic patients. Results suggest that the presented representation scheme provides various level of shape representation and the SVM can be a useful classifier in analyzing the shape differences between two groups. A stereoscopic-haptic virtual environment combining an auto-stereoscopic display with a force-feedback (or haptic) device takes an advantage of 3D applications for medicine because it improves space and depth perception.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.358-377
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• 2015

In this paper, we propose a novel approach for trajectory recovery. Our system uses a triangulation procedure for skeletonization and graph theory to extract the trajectory. Skeletonization extracts the polyline skeleton according to the polygonal contours of the handwritten characters, and as a result, the junction becomes clear and the characters that are touching each other are separated. The approach for the trajectory recovery is based on graph theory to find the optimal path in the graph that has the best representation of the trajectory. An undirected graph model consisting of one or more strokes is constructed from a polyline skeleton. By using the polyline skeleton, our approach accelerates the process to search for an optimal path. In order to evaluate the performance, we built our own dataset, which includes testing and ground-truth. The dataset consist of thousands of handwritten characters and word images, which are extracted from five handwritten documents. To show the relative advantage of our skeletonization method, we first compare the results against those from Zhang-Suen, a state-of-the-art skeletonization method. For the trajectory recovery, we conduct a comparison using the Root Means Square Error (RMSE) and Dynamic Time Warping (DTW) in order to measure the error between the ground truth and the real output. The comparison reveals that our approach has better performance for both the skeletonization stage and the trajectory recovery stage. Moreover, the processing time comparison proves that our system is faster than the existing systems.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.539-544
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• 1991

In order to verify robot motions for a desired work, it is necessary to visualize it on a computer screen. This paper presents a simulation algorithm for robot manipulator motion. Kinematic description is based on the Denavit- Hartenberg link representation. In order to be applied to various types of the robot manipulator, inverse kinematics make use of the Newton-Raphson iterative method with the least squares method. Joint variables are interpolated by the lowest polynomial segment satisfying acceleration continuity. The robot motions are generated and then animated on a computer screen in the form of skeleton type.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.722-725
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• 1990

This paper proposes a new path planning method for obstacle avoidance of mobile robot. In order to achieve easy planning of the path, a simple representation of the empty space is achieved based on thinning algorithm. The proposed Planning technique facilitates the direct use of information obtained by camera. Comparing to the V-graph method, the task of determining the shortest path from the resulting skeleton of empty space is optimized in terms of number of computation steps. The usefulness of the proposed method is ascertained by simulation.

• Journal of the Korea Society for Simulation
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• v.4 no.1
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• pp.1-11
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• 1995

The model of a FMS (Flexible Manufacturing System) admits to a natural hierarchical decomposition of highly decoupled units with similar structure and control. The FMS fractal architecture model represents a hierarchical structure built from elements of a single basic design. A SES (System Entity Structure) is a structural knowledge representation scheme that contains knowledge of decomposition, taxonomy, and coupling relationships of a system necessary to direct model synthesis. A substructure of a SES is extracted for use as the skeleton for a model. This substructure is called pruned SES and the extraction operation of a pruned SES from a SES is called pruning (or pruning operation). This paper presents a pruning operation called recursive pruning. It is applied to SES for generating a model structure whose sub-structure contains copies if itself as in FMS fractal architecture. Another pruning operation called delay pruning is also presented. Combined with recursive pruning the delay pruningis a useful tool for representing and constructing complex systems.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.904-907
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• 1996

In this paper, we propose an efficient collision-free path planning method of two cooperating robot manipulators grasping a common object rigidly. For given two robots and an object, the procedure is described which constructs the reduced dimensional configuration space by the kinematic analysis of two cooperating robot manipulators. A path planning algorithm without explicit representation of configuration obstacles is also described. The primary steps of the algorithm is as follows. First, we compute a graph which represents the skeleton of the free configuration space. Second, a connection between an initial and a goal configuration to the graph is searched to find a collision-free path.