• Journal of Korean Society of Disaster and Security
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• v.11 no.2
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• pp.37-43
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• 2018

The storm surge is caused by an typhoons and it is not easy to predict the location, strength, route of the storm. Therefore, research using a scenario for storms occurrence has been conducted. In Korea, hazard maps for various scenarios were produced using the storm surge numerical simulation. Such a method has a disadvantage in that it is difficult to predict when other scenario occurs, and it is difficult to cope with in real time because the simulation time is long. In order to compensate for this, we developed a method to predict the storm surge damage by using research database. The risk grade prediction for the storm surge was performed predominantly in the study area of the East coast. In order to estimate the equation, COMSOL developed by COMSOL AB Corporation was utilized. Using some assumptions and limitations, the form of the basic equation was derived. the constants and coefficients in the equation were estimated by the trial and error method. Compared with the results, the spatial distribution of risk grade was similar except for the upper part of the map. In the case of the upper part of the map, it was shown that the resistance coefficient, k was calculated due to absence of elevation data. The SIND model is a method for real-time disaster prediction model and it is expected that it will be able to respond quickly to disasters caused by abnormal weather.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.5
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• pp.64-74
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• 2019

Although a non-rigid registration has high demands in clinical practice, it has a high computational complexity and it is very difficult for ensuring the accuracy and robustness of registration. This study proposes a method of applying a non-rigid registration to 3D magnetic resonance images of brain in an unsupervised learning environment by using a deep-learning network. A feature vector between two images is produced through the network by receiving both images from two different patients as inputs and it transforms the target image to match the source image by creating a displacement vector field. The network is designed based on a U-Net shape so that feature vectors that consider all global and local differences between two images can be constructed when performing the registration. As a regularization term is added to a loss function, a transformation result similar to that of a real brain movement can be obtained after the application of trilinear interpolation. This method enables a non-rigid registration with a single-pass deformation by only receiving two arbitrary images as inputs through an unsupervised learning. Therefore, it can perform faster than other non-learning-based registration methods that require iterative optimization processes. Our experiment was performed with 3D magnetic resonance images of 50 human brains, and the measurement result of the dice similarity coefficient confirmed an approximately 16% similarity improvement by using our method after the registration. It also showed a similar performance compared with the non-learning-based method, with about 10,000 times speed increase. The proposed method can be used for non-rigid registration of various kinds of medical image data.

• Tuberculosis and Respiratory Diseases
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• v.41 no.3
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• pp.270-276
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• 1994

Background: The measurement of nonspecific bronchial hyperreactivity is valuable for diagnosis and management of bronchial asthma. Methacholine or histamine is used for the pharmacologic provocation test. Usually a methacholine bronchial provocation test is performed by a dosing technique with counted number of breaths. A dosimeter is indispensable in the dosing technique. Recently a timed tidal breathing technique which dose not need an expensive dosimeter was introduced. We measured the degree of nonspecific bronchial hyperreactivity to histamine using a simple timed tidal breathing technique. Method: Forty two healthy volunteers, 12 patients with bronchial asthma(BA), 10 patients with rhinitis(RH) and 10 patients with upper respiratory infection(URI) participated in the study. The subject's nose was clipped and inhalation continued during tidal breathing for 2 minutes via a face mask. $FEV_1$ was measured at 30 seconds, 90 seconds after inhalation and inhalation of next solution was continued until there was a fall in $FEV_1$ of 20%. Histamine PC20 was defined as the concentration at 20% fall of $FEV_1$ and it was obtained from the log dose-response curve by linear interpolation. Results: Inhalation of serial dilution of histamine could be performed in all patients without significant side effects. The geometric mean${\pm}$standard deviation of histamine PC20 in healthy volunteers is $8.27{\pm}2.22mg/ml$, BA group $0.33{\pm}3.02mg/ml$, RH group $0.85{\pm}3.24mg/ml$, and URI group $1.47{\pm}1.98mg/ml$. Conclusion: Histamine bronchial provocation test using timed tidal breath method is a simple and suitable tool for management of patients with bronchial hyperreactivity.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.4
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• pp.393-403
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• 2011

In this study, we suggested the period of tide observations is proper to calculate the mean sea level(MSL) precisely on Incheon tide station using wavelet analysis, and newly determined then the vertical reference surface of Korea using the calculated MSL. In order to calculate the height difference between the calculated MSL and specific ground station (ICGP) near the Incheon tide stations, we performed the laser measurements directly to the sea surface where located below ICGP. The orthometric-height of ICGP was determined that corrected the height difference to the calculated MSL using linear interpolation method. Finally, we connected the orthometric-height of ICGP with the original benchmark (ORBM) using GPS leveling methods for determining the new orthometric-height of ORBM. As the results, there is a variation amount of 0.026m between the new MSL was calculated in this study and old MSL was calculated in 1910's. Also, there is a difference of 0.035m between the new and old orthometric-heights of ORBM. The connection (or leveling) error of 0.009m was revealed in new orthometric height of ORBM with consideration of MSL variation which may caused by the error of GPS ellipsoid height and/or geoid model. In this study, we could be determined precisely the orthometric-height of ORBM based on the new MSL of Incheon Bay using only GPS leveling method, not a spirit leveling method. Therefore, it is necessary to determine the vertical datum strictly using long-term and continuously tide observations more than 19 years and to use the GPS leveling method widely in the height leveling work for the effective changeover from the orthonormal to the orthometric in national height system.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.113-127
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• 2012

Face detection methods using image processing have been proposed in many different ways. Generally, the most widely used method for face detection is an Adaboost that is proposed by Viola and Jones. This method uses Haar-like feature for image learning, and the detection performance depends on the learned images. It is well performed to detect face images within a certain distance range, but if the image is far away from the camera, face images become so small that may not detect them with the pre-learned Haar-like feature of the face image. In this paper, we propose the far distance face detection method that combine the Aadaboost of Viola-Jones with a saliency map and user's attention information. Saliency Map is used to select the candidate face images in the input image, face images are finally detected among the candidated regions using the Adaboost with Haar-like feature learned in advance. And the user's eye-tracking information is used to select the interest regions. When a subject is so far away from the camera that it is difficult to detect the face image, we expand the small eye gaze spot region using linear interpolation method and reuse that as input image and can increase the face image detection performance. We confirmed the proposed model has better results than the conventional Adaboost in terms of face image detection performance and computational time.

• The KIPS Transactions:PartA
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• v.16A no.6
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• pp.419-426
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• 2009

To realistically simulate fluid, the Navier-Stokes equations are generally used. Solving these Navier-Stokes equations on the Eulerian framework, the non-linear advection terms invoke heavy computation and thus Semi-Lagrangian methods are used as an approximated way of solving them. In the Semi-Lagrangian methods, the locations of advection sources are traced and the physical values at the traced locations are interpolated. In the case of Stam's method, there are relatively many chances of numerical losses, and thus there have been efforts to correct these numerical errors. In most cases, they have focused on the numerical interpolation processes, even simultaneously using particle-based methods. In this paper, we propose a new approach to reduce the numerical losses, through improving the tracing method during the advection calculations, without any modifications on the Eulerian framework itself. In our method, we trace the grids with the velocities which will let themselves to be moved to the current target position, differently from the previous approaches, where velocities of the current target positions are used. From the intuitive point of view, we adopted the simple physical observation: the physical quantities at a specific position will be moved to the new location due to the current velocity. Our method shows reasonable reduction on the numerical losses during the smoke simulations, finally to achieve real-time processing even with enhanced realities.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.26-36
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• 2006

In this paper, we propose a cost-effective color filter may (CFA) demosaicing method for digital still cameras in which a single CCD or CMOS image sensor is used. Since a CFA is adopted, we must interpolate missing color values in the red, green and blue channels at each pixel location. While most state-of-the-art algorithms invest a great deal of computational effort in the enhancement of the reconstructed image to overcome the color artifacts, we focus on eliminating the color artifacts with low computational complexity. Using spatial correlation of the adjacent pixels, the edge-directional information of the neighbor pixels is used for determining the edge direction of the current pixel. We apply our method to the state-of-the-art algorithms which use edge-directed methods to interpolate the missing color channels. The experiment results show that the proposed method enhances the demosaiced image qualify from $0.09{\sim}0.47dB$ in PSNR depending on the basis algorithm by removing most of the color artifacts. The proposed method was implemented and verified successfully using verilog HDL and FPGA. It was synthesized to gate-level circuits using 0.25um CMOS standard cell library. The total logic gate count is 12K, and five line memories are used.

• Journal of the Korea Society of Computer and Information
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• v.19 no.8
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• pp.35-44
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• 2014

This paper proposes a 3D pointing interface that is designed for the efficient application of a hand mouse. The proposed method uses depth images to secure high-quality results even in response to changes in lighting and environmental conditions and uses the normal vector of the palm of the hand to perform 3D pointing. First, the hand region is detected and tracked using the existing conventional method; based on the information thus obtained, the region of the palm is predicted and the region of interest is obtained. Once the region of interest has been identified, this region is approximated by the plane equation and the normal vector is extracted. Next, to ensure stable control, interpolation is performed using the extracted normal vector and the intersection point is detected. For stability and efficiency, the dynamic weight using the sigmoid function is applied to the above detected intersection point, and finally, this is converted into the 2D coordinate system. This paper explains the methods of detecting the region of interest and the direction vector and proposes a method of interpolating and applying the dynamic weight in order to stabilize control. Lastly, qualitative and quantitative analyses are performed on the proposed 3D pointing method to verify its ability to deliver stable control.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.187-193
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• 2012

Digital X-ray image detector has been applied for medical and industrial fields. Photoconductors have been used to convert the X-ray energy to electrical signal on the direct digital X-ray image detector and amorphous selenium (a-Se) has been used as a photoconductor, normally. In this work, we use 2-dimensional device (2-D) simulator to study about physical phenomena in the a-Se, when we irradiate electromagnetic radiation (${\lambda}=486nm$) on the a-Se surface. We evaluate the electron-hole generation rate, electron-hole recombination rate, and electron/hole distribution in the a-Se using 2-D simulator. This simulator divides the device into triangle and calculates using interpolation method. This simulation method has been proposed for the first time and we expect that it will be applied for the development of digital X-ray image detector.

• Smart Media Journal
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• v.2 no.4
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• pp.60-65
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• 2013

In this paper, we propose a high-resolution disparity map generation method using a low-resolution time-of-flight (TOF) depth camera and color camera. The TOF depth camera is efficient since it measures the range information of objects using the infra-red (IR) signal in real-time. It also quantizes the range information and provides the depth image. However, there are some problems of the TOF depth camera, such as noise and lens distortion. Moreover, the output resolution of the TOF depth camera is too small for 3D applications. Therefore, it is essential to not only reduce the noise and distortion but also enlarge the output resolution of the TOF depth image. Our proposed method generates a depth map for a color image using the TOF camera and the color camera simultaneously. We warp the depth value at each pixel to the color image position. The color image is segmented using the mean-shift segmentation method. We define a cost function that consists of color values and segmented color values. We apply a weighted average filter whose weighting factor is defined by the random walk probability using the defined cost function of the block. Experimental results show that the proposed method generates the depth map efficiently and we can reconstruct good virtual view images.