• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.469-474
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• 2009

This paper proposes an real time ray tracing system using optimized kd-tree traversal environment and ray/triangle intersection algorithm. The previous kd-tree traversal algorithms search for the upper nodes in a bottom-up manner. In a such way we need to revisit the already visited parent node or use redundant memory after failing to find the intersected primitives in the leaf node. Thus ray tracing for relatively complex scenes become more difficult. The new algorithm contains stacks implemented on GPU's local memory on CUDA framework, thus elegantly eliminate the problems of previous algorithms. After traversing the node we perform the latest CPU-based ray/triangle intersection algorithm 'Plucker coordinate test', which is further accelerated in massively parallel thanks to CUDA. Plucker test can drastically reduce the computational costs since it does not use barycentric coordinates but only simple test using the relations between a ray and the triangle edges. The entire system is consist of a single ray kernel simply and implemented without introduction of complicated synchronization or ray packets. Consequently our experiment shows the new algorithm can is roughly twice as faster as the previous.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.806-816
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• 2011

Interest about social security has recently increased in favor of safety for infrastructure. In addition, advances in computer vision and pattern recognition research are leading to video-based surveillance systems with improved scene analysis capabilities. However, such video surveillance systems, which are controlled by human operators, cannot actively cope with dynamic and anomalous events, such as having an invader in the corporate, commercial, or public sectors. For this reason, intelligent surveillance systems are increasingly needed to provide active social security services. In this study, we propose a core technique for intelligent surveillance system that is based on swarm robot technology. We present techniques for invader enclosing using swarm robots based on multiple distributed object environment. The proposed methods are composed of three main stages: location estimation of the object, specified object tracking, and decision of the cooperative behavior of the swarm robots. By using particle filter, object tracking and location estimation procedures are performed and a specified enclosing point for the swarm robots is located on the interactive positions in their coordinate system. Furthermore, the cooperative behaviors of the swarm robots are determined via the result of path navigation based on the combination of potential field and wall-following methods. The results of each stage are combined into the swarm robot-based invader-enclosing technique on multiple distributed object environments. Finally, several simulation results are provided to further discuss and verify the accuracy and effectiveness of the proposed techniques.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.11
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• pp.789-794
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• 2013

A vehicle tracking system makes it possible to induce the vehicle movement path for avoiding traffic congestion and to prevent traffic accidents in advance by recognizing traffic flow, monitoring vehicles, and detecting road accidents. To track the vehicles effectively, those which appear in a sequence of video frames need to identified by extracting the features of each object in the frames. Next, the identical vehicles over the continuous frames need to be recognized through the matching among the objects' feature values. In this paper, we identify objects by binarizing the difference image between a target and a referential image, and the labelling technique. As feature values, we use the center coordinate of the minimum bounding rectangle(MBR) of the identified object and the averages of 1D FFT(fast Fourier transform) coefficients with respect to the horizontal and vertical direction of the MBR. A vehicle is tracked in such a way that the pair of objects that have the highest similarity among objects in two continuous images are regarded as an identical object. The experimental result shows that the proposed method outperforms the existing methods that use geometrical features in tracking accuracy.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.56-60
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• 2016

Neutral or alkaline papermaking provides many advantages in paper strength and processing conditions. It also provides the opportunity of using calcium carbonate fillers in papermaking. These diverse advantages have made almost all paper machines of printing and writing papers run under neutral and alkaline conditions. On the other hand, linerboard machines, which use recycled papers as a raw material, are running under acid conditions using a rosin sizing system. Because the recycled raw materials used by the linerboard industry contain significant amounts of alkaline papers, the linerboard industry has an interest in the possibility of using the neutral or alkaline papermaking opportunity. In this study, the compatibility of the recycled linerboards under neutral or alkaline papermaking conditions was examined by recycling them under various pH conditions. The sizing degree of the papers recycled under neutral or alkaline was significantly lower than that of acid formed papers indicating that during the neutral or alkaline recycling process the rosin sized papers lost their sizing efficiency. Recycling of acid formed linerboards under neutral or alkaline conditions increased the amount of foam, and the foam contained substantial amount of solid materials derived from the acid sizing systems. Use of cationic polyelectrolytes including PEI and poly-DADMAC improved the sizing degree of the recycled papers under neutral and alkaline conditions. PEI decreased the foam generation as well while poly-DADMAC did not show any reducing effect of the foam. These results suggest that PEI forms coordinate bonds with rosin acid and precipitate them onto the surface of recycled fibers, while the reaction products between poly-DADMAC and rosin acid ions still remain water soluble under neutral or alkaline conditions.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.731-744
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• 2007

A method for dynamic analysis and design calculation of a Powertrain Mounting System(PMS) including Hydraulic Engine Mounts(HEM) is developed with the aim of controlling powertrain motion and reducing low-frequency vibration in pitch and bounce modes. Here the pitch mode of the powertrain is defined as the mode rotating around the crankshaft of an engine for a transversely mounted powertrain. The powertrain is modeled as a rigid body connected to rigid ground by rubber mounts and/or HEMs. A mount is simplified as a three-dimensional spring with damping elements in its Local Coordinate System(LCS). The relation between force and displacement of each mount in its LCS is usually nonlinear and is simplified as piecewise linear in five ranges in this paper. An equation for estimating displacements of the powertrain center of gravity(C.G.) under static or quasi-static load is developed using Newton's second law, and an iterative algorithm is presented to calculate the displacements. Also an equation for analyzing the dynamic response of the powertrain under ground and engine shake excitations is derived using Newton's second law. Formulae for calculating reaction forces and displacements at each mount are presented. A generic PMS with four rubber mounts or two rubber mounts and two HEMs are used to validate the dynamic analysis and design calculation methods. Calculated displacements of the powertrain C.G. under static or quasi-static loads show that a powertrain motion can meet the displacement limits by properly selecting the stiffness and coordinates of the tuning points of each mount in its LCS using the calculation methods developed in this paper. Simulation results of the dynamic responses of a powertrain C.G. and the reaction forces at mounts demonstrate that resonance peaks can be reduced effectively with HEMs designed on the basis of the proposed methods.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.1
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• pp.97-105
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• 1997

In order to conserve architecture accurately as original feature, we need to get the data which is measured in detail about the information of size, position, type, shape, and other terms for architectures. Recently, we need to get data fast and correctly, to compose and to update the database of geographic information system, but using existing method. it is difficult to update the data effectively in the rapid development of information industry. In this study, therefore, It is measured precisely architecture using accurate close-range photogrammetry The aims of this study are real-measured plan by processing acquired image through multi-image matching method if photogrammetry, suggesting the method which is able to draw in detail front plane and plane of well-established architecture, and giving data to obtain accurate size and 3-D coordinate using analytical method.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.303-308
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• 2006

In this paper, the authors calculated manoeuvring motions of a large container vessel approaching to the newly built container piers to get alongside to her berth in Busan harbour. The motion calculations were done by using fixed coordinate system and the object of the calculations is to check the manoeuvring motions are safe or not for berthing the large vessel to her berth. The result of calculations manifested that a large container vessel can get alongside to the piers without any difficulty under normal weather conditions by using 2 Z. Peller tug boats of 4500 H.P. each and also these demonstrated it is difficult to conduct and get her alongside to the piers under rough weather conditions of wind force 16.9m/sec or more. Under rough weather conditions of 6 by beaufort scale the average wind velocity is about 13.5m and if we add 25% increase of the normal velocity to it, the wind will becomes a gust of 16.9m/sec. So it is advisable to avoid conducting a large container vessel to the pier under the rough weather conditions of 6 or more by beaufort scale. Also, I is better to use 3 Z. peller tug boats of 4500 HP. each under the above mentioned rough weather in a case of unavoidable circumstances.

• Journal of Korea Multimedia Society
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• v.17 no.7
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• pp.818-828
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• 2014

After emerging of Microsoft Kinect, the interest in three-dimensional (3D) depth image was significantly increased. Depth image data of an object can be converted to 3D coordinates by simple arithmetic calculation and then can be reconstructed as a 3D model on computer. However, because the surface coordinates can be acquired only from the front area facing Kinect, total solid which has a closed surface cannot be reconstructed. In this paper, 3D registration method for multiple Kinects was suggested, in which surface information from each Kinect was simultaneously collected and registered in real time to build 3D total solid. To unify relative coordinate system used by each Kinect, 3D perspective transform was adopted. Also, to detect control points which are necessary to generate transformation matrix, 3D randomized Hough transform was used. Once transform matrices were generated, real time 3D reconstruction of various objects was possible. To verify the usefulness of suggested method, human arms were 3D reconstructed and the volumes of them were measured by using four Kinects. This volume measuring system was developed to monitor the level of lymphedema of patients after cancer treatment and the measurement difference with medical CT was lower than 5%, expected CT reconstruction error.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2365-2370
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• 2017

In this paper, we propose a motion and position recognition technique considering an experiential VR environment. Motion recognition attaches a plurality of AHRS devices to a body part and defines a coordinate system based on this. Based on the 9 axis motion information measured from each AHRS device, the user's motion is recognized and the motion angle is corrected by extracting the joint angle between the body segments. The location recognition extracts the walking information from the inertial sensor of the AHRS device, recognizes the relative position, and corrects the cumulative error using the BLE fingerprint. To realize the proposed motion and position recognition technique, AHRS-based position recognition and joint angle extraction test were performed. The average error of the position recognition test was 0.25m and the average error of the joint angle extraction test was $3.2^{\circ}$.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.216-219
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• 2004

In this study, the concept and techniques to generate the level lA, lB and 2A image products have been reviewed. In particular, radiometric and geometric corrections and bands registration used to generate level lA, lB and 2A products have been focused in this study. Radiometric correction is performed to take into account radiometric gain and offset calculated by compensating the detector response non-uniformity. And, in order to compensate satellite altitude, attitude, skew effects, earth rotation and earth curvature, some geometric parameters for geometric corrections are computed and applied. Bands registration process using the matching function between a geometry, which is called 'reference geometry', and another one which is corresponds to the image to be registered is applied to images in case of multi-spectral imaging mode. In order to generate level-lA image products, a simple radiometric processing is applied to a level-0 image. Level-lB image has the same radiometry correction as a level-lA image, but is also issued from some geometric corrections in order to compensate skew effects, Earth rotation effects and spectral misregistration. Level-2A image is generated using some geo-referencing parameters computed by ephemeris data, orbit attitudes and sensor angles. Level lA image is tested by visual analysis. The difference between distances calculated level 1 B image and distances of real coordinate is tested. Level 2A image is tested Using checking points.