• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.58-66
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• 2012

Even after establishment of H.264/AVC standard, the video coding experts group (VCEG) of ITU-T has researched on development of promising coding techniques to increase coding efficiency based on the key technology area (KTA) software. Recently, the joint collaboration team video coding (JCT-VC) which was composed of the VCEG and the motion picture experts group (MPEG) of ISO/IEC is developing a next-generation video standard namely HEVC intended to gain twice efficiency than H.264/AVC. An adaptive interpolation technique, one of various next-generation techniques, reported higher coding efficiency. However, it has high computational complexity and does not deal with various error characteristics for videos. In this paper, we investigate characteristics of interpolation filters and propose an effective fixed interpolation filter bank including diverse properties of error. Experimental results is shown that the proposed method achieved bitrate reduction by 0.7% and 1.3% compared to fixed directional interpolation filter (FDIF) of the KTA and the directional interpolation filter (DIF) of the HEVC test model, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.103-110
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• 2008

When there is uncertainty in topological rate of change, motility model and terrain condition, the performance severely degrades in MANET. The concept of transition of routing protocol on the fly according to the network parameters such as coverage, connectivity and mobility etc. may counterbalance the problems stated above. The mathematical modeling of feedback parameters has been derived, and the architecture for the multi-routing protocol system providing an adaptation from one routing protocol to another is also investigated. This paper is extensively devoted on the analysis of mobility, connectivity and their effects on the network and finally transition into another routing protocol according to them.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4C
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• pp.277-282
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• 2012

In this paper, we present a real-time eye contact system for realistic telepresence using a Kinect depth camera. In order to generate the eye contact image, we capture a pair of color and depth video. Then, the foreground single user is separated from the background. Since the raw depth data includes several types of noises, we perform a joint bilateral filtering method. We apply the discontinuity-adaptive depth filter to the filtered depth map to reduce the disocclusion area. From the color image and the preprocessed depth map, we construct a user mesh model at the virtual viewpoint. The entire system is implemented through GPU-based parallel programming for real-time processing. Experimental results have shown that the proposed eye contact system is efficient in realizing eye contact, providing the realistic telepresence.

• Computational Structural Engineering
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• v.10 no.4
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• pp.217-228
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• 1997

The high precision analysis by the p-version of the finite element method are fairly well established as highly efficient method for linear elastic problems, especially in the presence of stress singularity. It has been noted that the merits of the p-version are accuracy, modeling simplicity, robustness, and savings in user's and CPU time. However, little has been done to exploit their benefits in elasto-plastic analysis. In this paper, the p-version finite element model is proposed for the materially nonlinear analysis that is based on the incremental theory of plasticity using the constitutive equation for work-hardening materials, and the associated flow rule. To obtain the solution of nonlinear equation, the Newton-Raphson method and initial stiffness method, etc are used. Several numerical examples are tested with the help of the square plates with cutout, the thick-walled cylinder under internal pressure, and the circular plate with uniformly distributed load. Those results are compared with the theoretical solutions and the numerical solutions of ADINA

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.783-790
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• 2016

One of the main factors related to the deterioration of estimation accuracy in inertial measurement unit (IMU)-based orientation determination is the object's acceleration. This is because accelerometer signals under accelerated motion conditions cannot be longer reference vectors along the vertical axis. In order to deal with this issue, some orientation estimation algorithms adopt acceleration-compensating mechanisms. Such mechanisms include the simple switching techniques, mechanisms with adaptive estimation of acceleration, and acceleration model-based mechanisms. This paper compares these three mechanisms in terms of estimation accuracy. From experimental results under accelerated dynamic conditions, the following can be concluded. (1) A compensating mechanism is essential for an estimation algorithm to maintain accuracy under accelerated conditions. (2) Although the simple switching mechanism is effective to some extent, the other two mechanisms showed much higher accuracies, particularly when test conditions were severe.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.75-81
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• 2012

This paper has proposed Message Count Control Mechanism based Link State Update(LSU) Algorithm that has not had a strong influence on the depreciation of QoS routing performance. Most existing LSU algorithms have the limit that cannot control the count of LSU message. Especially, adaptive algorithms have a bad performance when traffic are excessive and fickle. We classify as the importance of LSU message that have a influence on available bandwidth and determine the transmission of the message according to update rate per a unit of time. We have evaluated the performance of the proposed model and the existing algorithms on MCI simulation network using the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.2
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• pp.69-78
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• 2002

This paper addresses a method to automatically detect out a person's face from a given image that consists of a hair and face view of the person and a complex background scene. Out method involves an effective detection algorithm that exploits the spatial distribution characteristics of human skin color via an adaptive fuzzy color classifier (AFCC), The universal skin-color map is derived on the chrominance component of human skin color in Cb, Cr and their corresponding luminance. The desired fuzzy system is applied to decide the skin color regions and those that are not. We use RGB model for extracting the hair color regions because the hair regions often show low brightness and chromaticity estimation of low brightness color is not stable. After some preprocessing, we apply convex-hull to each region. Consequent face detection is made from the relationship between a face's convex-hull and a head's convex-hull. The algorithm using the convex-hull shows better performance than the algorithm using pattern method. The performance of the proposed algorithm is shown by experiment. Experimental results show that the proposed algorithm successfully and efficiently detects the faces without constrained input conditions in color images.

• Journal of Korean Biological Nursing Science
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• v.17 no.1
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• pp.37-43
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• 2015

Purpose: Stress, depending on its intensity and duration, results in either adaptive or maladaptive physiological and psychological changes in humans. Also, it was found that stressful experiences increase the signs of behavioral despair in rodents. On the other hand, exercise and melatonin treatment is believed to have many beneficial effects on health. Thus, this study was designed to evaluate the anti-depressant effects of physical activity and melatonin against chronic stress-induced depression in rats. Methods: Adult male Sprague-Dawley(SD) rats(200-250g, 7 weeks of age) were subjected to depression induced by chronic stress. Chronic depression was induced with forced-swim stress (FSS) and repeated change of light-dark cycle for 4 weeks. In the last 2 weeks, some rats were confined in a cage enriched with a running wheel, seesaw and chewed a ball from 19:00 to 07:00 every day. Melatonin was injected intra-peritoneally (I.P), and the rats received intraperitoneal injections of melatonin (15 mg/kg). The Forced Swim Test (FST) was performed to evaluate the immobility behaviors of rats for a 5 min test. Results: It was found that, the immobility time in FST was significantly (p<.05) lower in physical exercise ($M=58.83{\pm}22.73$) and melatonin ($M=67.33{\pm}37.73$) than in depressive rats ($M=145.93{\pm}63.16$) without physical activity. Also, TPH positive cell in dorsal raphe was significantly (p<.05) higher in exercise ($M=457.38{\pm}103.21$) and melatonin ($M=425.38{\pm}111.56$) than in depressive rats ($M=258.25{\pm}89.13$). Conclusion: This study suggests that physical activity and melatonin produces antidepressant-like effect on stress-induced depression in rats. So, physical exercise and melatonin may be a good intervention in depression patients.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.3
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• pp.262-268
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• 2010

In this paper, this study restores the distorted image to its original image by compensating for the distortion of image from a fixed-focus camera lens. The various developments and applications of the imaging devices and the image sensors used in a wide range of industries and expanded use, but due to the needs of the small size and light weight of the camera, the distortion from acquiring images of the distorted curvature of the lens tends to affect many. In particular, the three-dimensional imaging camera, each different distortion of left and right lens cause the degradation of three-dimensional sensitivity and left-right image distortion ratio. we approached the way of generalizing the approximate equations to restore each part of left-right camera images to the coordinators of the original images. The adaptive Neuro-Fuzzy Inference System is configured for it. This system is divided from each membership function and is inferred by 1st order Sugeno Fuzzy model. The result is that the compensated images close to the left, right original images. Using low-cost and compact imaging lens by which also determine the exact three-dimensional image-sensing capabilities and will be able to expect from this study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.431-435
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• 2005

Mobile Ad-Hoc network is the network(MANET) of mobile nodes which has no fixed infrastructure, and mobile node in MANET can move and communicate freely each other. Recently, many researches for mobility management of mobile nodes are actively carried out by using the location information of mobile nodes. The location management is an important issue in MANET because location information of mobile node is frequently changed in MANET. In this paper, an adaptive mobility management scheme using fuzzy-logic based GQS by considering the mobile locality is proposed in order to manage location information of mobile nodes in MANET efficiently. The proposed scheme selects mobility databases adaptively from GQS by considering the locality of mobile node. The performance of the mobility management scheme proposed in this paper is evaluated by an analytic model and compared with that of existing UQS based mobility management scheme.