• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.83-90
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• 2006

Recently, as the technology of utilization for the ocean space is being advanced, floating structures are asked for being mare and mare huge-scale. A very large floating structure(VLFS) is considered as a flexible structure, because of a quite large length-to-breadth ratio and its geometrical flexibility. The main object of this study is to develop an accurate and convenient method on the hydroelastic response analysis of very large offshore structures on the real sea states. The numerical approach for the hydorelastic responses is based on the combination of the three dimensional source distribution methods, the dynamic response analysis method and the spectral analysis method. A model is considered as many rigid bodies connected elastic beam elements. The calculated results shaw good agreement with the experimental and calculated ones by Ohta.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.335-341
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• 2011

In this paper, we proposed an automatic packing mechanism of one station concept for fastener objects where the continuous work is performed in a finite space. The proposed packing mechanism is composed of supporting frame, feeding supply, air shower device, clamping/opening device, batch charging device, sealing/cutting device and supply adjusting device. And, these mechanisms have been modularized through mechanical, dynamical, structural and fluid optimized design using the SMO(SimDesigner Motion) analysis module. Also, the virtual prototype was carried out using the 3-D CAD program. The packing process is consisted performed in the order of feeding, clamping, bottom sealing, cutting, opening, object charging, closing and the upper sealing. And the time of these cycles were designed to be completed in 15-20 seconds. This packing mechanism will be created as a prototype in the near future. In addition, it will be applied to the production scenes after going through a field test for the validation of performance.

• ETRI Journal
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• v.37 no.4
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• pp.743-751
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• 2015

Cloud gaming services are heavily dependent on the efficiency of real-time video streaming technology owing to the limited bandwidths of wire or wireless networks through which consecutive frame images are delivered to gamers. Video compression algorithms typically take advantage of similarities among video frame images or in a single video frame image. This paper presents a method for computing and extracting both graphics information and an object's boundary from consecutive frame images of a game application. The method will allow video compression algorithms to determine the positions and sizes of similar image blocks, which in turn, will help achieve better video compression ratios. The proposed method can be easily implemented using function call interception, a programmable graphics pipeline, and off-screen rendering. It is implemented using the most widely used Direct3D API and applied to a well-known sample application to verify its feasibility and analyze its performance. The proposed method computes various kinds of graphics information with minimal overhead.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.32-41
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• 1990

This paper proposes a method of using image features in serving a robot manipulator. Specifically, the con-cept 'feature' is first mathematically defined and then differential relationship between the robot motion and feature vector is derived in terms of Feature Jacobian Matrix and its generalized inverse. Also, by using more features than the number of DOFs of the robot, the visual servoing performance is shown to be improv-ed. Via various examples, the method of feature-based servoing of a robot proposed in this paper is proved to be effective for conducting object-oriented robotic tasks.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.10
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• pp.89-94
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• 2012

This research is to apply the control of neuron networks for the real-time walking control of Multi-articulated robot. Multi-articulated robot is expressed with a complicated mathematical model on account of the mechanic, electric non-linearity which each articulation of mechanism has, and includes an unstable factor in time of walking control. If such a complex expression is included in control operation, it leads to the disadvantage that operation time is lengthened. Thus, if the rapid change of the load or the disturbance is given, it is difficult to fulfill the control of desired performance. This paper proposes a new mode to implement a neural network controller by installing a real object for controlling and an algorithm for this, which can replace the existing method of implementing a neural network controller by utilizing activation function at the output node. The proposed control algorithm generated control signs corresponding to the non-linearity of Multi-articulated robot, which could generate desired motion in real time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1919-1925
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• 2013

This paper proposes a background image extraction algorithm for traffic environment analysis in a school zone. The proposed algorithm solves the problems by level changes and stationary objects to be occurred frequently in traffic environment. For the former, it renews rapidly the background image toward the current frame using a fast Sima-Delta algorithm and for the latter, it excludes the stationary objects from the background image by detecting dynamic regions using a just previous frame and a background image averaged for a long time. The results of experiments show that the proposed algorithm adapts quickly itself to level change well, and reduces about 40~80% of SAD in background region in comparison with the conventional algorithms.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3325-3327
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• 1999

A microgripper driven by E-T (electro-thermal) actuators has been designed and fabricated by surface micromachining. This microgripper consists of two E-T actuators. Each actuator has two arms with different widths joined at the end to form a 'U' shape. The wider 'cold' arm has a narrow flexure at the end (anchor or electrode side) for easy bending, This actuator can be fabricated with only two masks - one for the sacrificial layer and the other for the poly-Si structure layer. An E-T actuator bends its arm due to unequal thermal expansion between the 'cold' arm and the 'hot' arm, This actuator tip moves laterally in an arcing motion towards the cold arm side when the structure is unevenly heated by the applied current. Therefore each microgripper is actuated inwards and can hold a micro object. The fabricated E-T actuator was operated in the range of $2{\sim}12V$ and $1{\sim}5mA$. and maximum tip displacement was $13.6{\mu}m$. This device may become useful in many applications because an E-T actuator can be designed and fabricated easily, and obtain large displacement.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.175-182
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• 2005

This paper presents encryption techniques for digital right management solutions of MPEG-4 streams. MPEG-4 is a format for multimedia streaming and stored in the MPEG-4 file format. We designed three kinds of encryption methods, which encrypt macro blocks (MBs) or motion vectors (MVs) of I-, P-VOPs (Video Object Planes), extracted from the MPEG-4 file format. We used DES to encrypt MPEG-4 data Based on theses three methods, we designed and implemented a DRM solution for an Internet broadcasting service, which enabled a MPEG-4 data streaming, and then compared the results of decryption speed and quality of rendered video sequences to get an optimal encryption method.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.545-554
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• 2005

Passive velocity field control (PVFC) was previously developed for fully mechanical systems, in which the motion task was specified by behaviors in terms of a velocity field and the closed-loop was passive with respect to the supply rate given by the environment input. However, the PVFC was only applied to a single manipulator. The proposed control law was derived geometrically and the geometric and robustness properties of the closed-loop system were also analyzed. In this paper, we propose a virtual passivity-based algorithm to apply decentralized control to multiple 3­wheeled mobile robotic systems whose subsystems are under nonholonomic constraints and convey a common rigid object in a horizontal plain. Moreover, it is shown that multiple robot systems ensure stability and the velocities of augmented systems converge to a scaled multiple of each desired velocity field for cooperative mobile robot systems. Finally, the application of proposed virtual passivity-based decentralized algorithm via system augmentation is applied to trace a circle and the simulation results is presented in order to show effectiveness for the decentralized control algorithm proposed in this research.

• Journal of Korea Multimedia Society
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• v.3 no.2
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• pp.157-163
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• 2000

Introduction of motion video including live video into network virtual reality systems makes virtual spaces more attractive. To handle live video in networked virtual reality s)'stems based on VRML, the scalability of networked virtual reality systems becomes very important on the internet where the performance of the network and the end systems varies dynamically. In this paper, a new quality control algorithm suitable for scalable networked virtual reality systems with live video capability is proposed. Our approach is to introduce the notion of the importance of presence (IoP) which represents the importance of objects in virtual spaces. According to IoPs, the degree of the deterioration of each object presentation will be determined in case of the starvation of system resources.