• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.502-507
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• 1998

Two different types the CANDU fuel bundles hue been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void paction distributions in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From calculated mixture enthalpy distribution at the exit of fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful assessing thermal behavior of the fuel bundle that could be used in CANDU reactors.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.215-218
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• 2013

In this paper, we proposed a method for enhancement of color images with sky regions. The input image is converted into HSV space and then sky and non-sky regions are separated. For sky region, saturation enhancement is performed for each pixel based on the enhancement factor calculated from the average saturation of its local neighborhood. On the other hand, for the non-sky region, the enhancement is applied only on the luminance value (V) component of the HSV color image, which is performed in two steps. The luminance enhancement, which is also called as dynamic range compression, is carried out using nonlinear transfer function. Again, each pixel is further enhanced for the adjustment of the image contrast depending upon the center pixel and its neighborhood pixel values. At last, the original H and V component image and enhanced S component image for the sky region, and original H and S component image and enhanced V component image for the non-sky region are converted back to RGB image.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.1 s.256
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• pp.99-108
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• 2007

In this study, the NOx formation characteristics of one-dimensional $CH_4$/Air premixed flame using detailed-kinetic chemistry are examined numerically. The combustor length and the amount of heat loss are varied to investigate the effect of residence time and heat loss on the NOx formation in a post-flame region. In the flame region, NO is mainly produced by the Prompt NO mechanism including $N_2$O-intermediate NO mechanism over all equivalence ratios. However, thermal NO mechanism is more important than Prompt NO mechanism in the post-flame region. In the case of adiabatic condition, the increase of combustor length causes the remarkable increase of NO emission at the exit due to the increase of residence time. On the other hand, NO reaches the equilibrium state in the vicinity of flame region, considering radiation and conduction heat losses. Furthermore the NO, in the case of $\phi$=1.2, is gradually reduced in the downstream region as the heat loss is increased. From these results, it can be concluded that the controls of residence time and heat loss in a combustor should be recognized as an important NOx reduction technology.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.11-18
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• 2018

To interact with a virtual object in immersive virtual environment, the target object should be selected quickly and accurately. Conventional 3D ray casting method using a direction of user's hand or head allows the user to select an object quickly. However, accuracy problem occurs when selecting an object using conventional methods among occlusion of objects. In this paper, we propose a region of interest based selection method that enables to select an object among occlusion of objects using a combination of gaze tracking and hand gesture recognition. When a user looks at a group of occlusion of objects, the proposed method recognizes user's gaze input, and then region of interest is set by gaze input. If the user wants to select an object among them, the user gives an activation hand gesture. Then, the proposed system relocates and visualizes all objects on a virtual active window. The user can select an object by a selecting hand gesture. Our experiment verified that the user can select an object correctly and accurately.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.4
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• pp.145-154
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• 2008

In this paper, we propose the pet robot control system using hand gesture recognition in image sequences acquired from a camera affixed to the pet robot. The proposed system consists of 4 steps; hand detection, feature extraction, gesture recognition and robot control. The hand region is first detected from the input images using the skin color model in HSI color space and connected component analysis. Next, the hand shape and motion features from the image sequences are extracted. Then we consider the hand shape for classification of meaning gestures. Thereafter the hand gesture is recognized by using HMMs (hidden markov models) which have the input as the quantized symbol sequence by the hand motion. Finally the pet robot is controlled by a order corresponding to the recognized hand gesture. We defined four commands of sit down, stand up, lie flat and shake hands for control of pet robot. And we show that user is able to control of pet robot through proposed system in the experiment.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.3
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• pp.103-114
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• 2004

This paper deals with a system that is capable of recognizing hand-signals in 3-dimensional space. The system uses 2 color cameras as input devices. Vision-based gesture recognition system is known to be user-friendly because of its contact-free characteristic. But as with other applications using a camera as an input device, there are difficulties under complex background and varying illumination. In order to detect hand region robustly from a input image under various conditions without any special gloves or markers, the paper uses previous position information and adaptive hand color model. The paper defines a hand-signal as a combination of two basic elements such as 'hand pose' and 'hand trajectory'. As an extensive classification method for hand pose, the paper proposes 2-stage classification method by using 'small group concept'. Also, the paper suggests a complementary feature selection method from images from two color cameras. We verified our method with a hand-signal application to our driving simulator.

• Journal of the Korean Society of School Health
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• v.35 no.3
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• pp.123-132
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• 2022

Purpose: The purpose of this study is to identify factors related to hand washing practice among adolescents before and after the outbreak of the COVID-19 pandemic. Methods: The study was conducted using data from the 15th~16th (2019~2020) Korea Youth Risk Behavior Web-based Survey, and the subjects of the study were 57,303 and 54,948 people who participated in the 2019 and 2020 study, respectively. The data were analyzed with frequency test, rao-scott 𝑥² test and multiple logistic regression analysis using SPSS 27.0. Results: Changes in the hand washing practice rate were observed before and after the COVID-19 pandemic in all five behaviors; before eating in school, after using the toilet in school, before eating at home, after using the toilet at home, and after returning home. The study found that the hand washing practice rate increased by 1.21-2.43 times after the COVID-19 pandemic. In addition, as a result of logistic regression analysis, the hand washing practice rate before and after the COVID-19 pandemic was related to gender, region, school grade, school type, economic status, health status, and personal hygiene education experience. Conclusion: This study confirmed the importance of hand washing education to improve the hand washing practice rate in adolescents. It is necessary to develop and apply an effective youth hand washing education program in consideration of various variables that appeared as significant factors influencing the hand washing practice rate before and after the COVID-19 pandemic.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.586-589
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• 2015

A computer presentation system by using hand-motion identification rules is proposed. To identify hand motions of a presenter, a face region is extracted first using haar classifier. A motion status(patterns) and position of hands is discriminated using the center of gravities of user's face and hand after segmenting the hand area on the YCbCr color model. User's hand is applied to the motion detection rules and then presentation control command is then executed. The proposed system utilizes the motion identification rules without the use of additional equipment and it is then capable of controlling the presentation and does not depend on the complexity of the background. The proposed algorithm confirmed the stable control operation via the presentation of the experiment in the dark illumination range of indoor atmosphere (lx) 15-20-30.

• The Journal of Korean Physical Therapy
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• v.31 no.3
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• pp.157-160
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• 2019

Purpose: We compared the activation pattern of the mirror neurons (MN) between two types of hand movement according to action observation using functional MRI. Methods: Twelve right-handed healthy subjects (5 male and 7 female, mean age $21.92{\pm}2.02years$) participated in the experiment. During fMRI scanning, subjects underwent two different stimuli on the screen: 1) video clips showing repeated grasping and releasing of the ball via simple hand movement (SHM), and (2) video clips showing an actor performing a Purdue Pegboard test via complex hand movement (CHM). paired t-test in statistical parametric mapping (SPM) was used to compare the activation differences between the two types of hand movement. Results: CHM as compared with the SHM produced a higher blood oxygen level dependent (BOLD) signal response in the right superior frontal gyrus, left inferior and superior parietal lobules, and lingual gyrus. However, no greater BOLD signal response was found by SHM compared with CHM (FWE corrected, p<0.05). Conclusion: Our findings provided that the activation patterns for observation of SHM and CHM are different. CHM also elicited boarder or stronger activations in the brain, including inferior parietal lobule called the MN region.

• The Journal of the Korea Contents Association
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• v.18 no.4
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• pp.398-405
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• 2018

In the HCI, hand gesture recognition is attracting attention as a method for interaction and information exchange between users and devices along with the development of IT devices. In hand gesture recognition through image processing, palm region detection is a key process contributing to improvement of processing speed and recognition rate. In this paper, we propose a new method for image segmentation between the hand and wrist for palm area detection. The anatomical characteristics of the hand are used to calculate the distance between the iliac bones of the thumb and little finger, which have the widest width, by the horizontal projection histogram of the hand image, and then the palm area is detected by drawing a circle having the width as the diameter. In order to verify the superiority of this method, multiple stage template matching is used to compare and evaluate recognition performance against the four conventional methods for 10 hand gestures. Note that the literatures to offer palm area detection performance evaluation are few although there are many studies on hand gesture recognition.