• Title/Summary/Keyword: 원거리장

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Augmented Reality Based Remote 3D Collaborative Design Workspace (증강현실 기반의 원격 3차원 디자인 협업 환경에 관한 연구)

  • SaKong, Kyung;Nam, Tek-Jin
    • 한국HCI학회:학술대회논문집
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    • 2006.02b
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    • pp.221-226
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    • 2006
  • 원격 3차원 디자인 협업 환경이란 원거리에 있는 디자이너들이 3차원 모델을 함께 동시적으로 다루는 협업 환경으로서, 제품 개발 프로세스의 비용과 시간을 단축하는데 매우 중요한 역할을 한다. 그러나 이에 대한 연구는 아직 미비한 실정이며 기존의 연구들도 2차원 데스크탑 환경에 제한된 문제점이 있다. 따라서 본 연구는 새로운 협업 환경의 제안을 통해 지리적으로 떨어진 디자이너들간의 3D 모델에 관한 원활한 협업을 촉진하는 것을 목표로 한다. 본 연구에서 제안한 증강현실 기반의 원격 3차원 디자인 협업 환경은 3D 모델의 공유를 위한 회전 원반(turntable)과 상대의 위치 및 제스처 정보를 제공하는 가상 그림자(virtual shadows)로 구성된다. 동시적으로 회전하는 회전원반은 물리적인 매개체로서 가상물체와 실제 세계를 자연스럽게 연결하는 동시에 상대의 실재감을 높인다. 가상그림자는 가상물체 주위로 보여지는 사람들의 손과 팔의 움직임을 시각화하여 공유하는 것으로, 상대의 위치뿐 아니라 지시, 제스처 등 행동에 대한 인식이 지속적으로 이루어지게 한다. 프로토타입을 제작하고 사용자 평가 실험을 실시하여 3차원 모델을 검토하는 단계에 그 유용성이 있음을 확인하였다. 데스크탑 환경의 모델링 툴에 익숙한 사용자들은 실제 공간에서 가상물체를 조작할 수 있음에 긍정적인 반응을 보였고 회전원반과 가상그림자의 제공은 태스크 수행의 정확도를 높이며 협업을 촉진하는 결과를 보였다. 본 연구는 환경적 제약으로 원활하게 이루어지지 못했던 3D 모델에 관한 원격 협업에 의사소통의 장을 마련하고 이를 촉진시킨다는 점에서 그 의의가 있다. 본 환경에서 제시한 상대방과 협업대상물에 대한 심리적, 물리적 공유 감을 증대시키는 방법들은 3D 모델에 관한 디자인 협업에서 확장되어 다른 원격 협업을 지원하는 데도 적용될 수 있을 것이다.

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Region-Based Reconstruction Method for Resolution Enhancement of Low-Resolution Facial Image (저해상도 얼굴 영상의 해상도 개선을 위한 영역 기반 복원 방법)

  • Park, Jeong-Seon
    • Journal of KIISE:Software and Applications
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    • v.34 no.5
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    • pp.476-486
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    • 2007
  • This paper proposes a resolution enhancement method which can reconstruct high-resolution facial images from single-frame, low-resolution facial images. The proposed method is derived from example-based reconstruction methods and the morphable face model. In order to improve the performance of the example-based reconstruction, we propose the region-based reconstruction method which can maintain the characteristics of local facial regions. Also, in order to use the capability of the morphable face model to face resolution enhancement problems, we define the extended morphable face model in which an extended face is composed of a low-resolution face, its interpolated high-resolution face, and the high-resolution equivalent, and then an extended face is separated by an extended shape vector and an extended texture vector. The encouraging results show that the proposed methods can be used to improve the performance of face recognition systems, particularly to enhance the resolution of facial images captured from visual surveillance systems.

Reconstruction of High-Resolution Facial Image Based on Recursive Error Back-Projection of Top-Down Machine Learning (하향식 기계학습의 반복적 오차 역투영에 기반한 고해상도 얼굴 영상의 복원)

  • Park, Jeong-Seon;Lee, Seong-Whan
    • Journal of KIISE:Software and Applications
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    • v.34 no.3
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    • pp.266-274
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    • 2007
  • This paper proposes a new reconstruction method of high-resolution facial image from a low-resolution facial image based on top-down machine learning and recursive error back-projection. A face is represented by a linear combination of prototypes of shape and that of texture. With the shape and texture information of each pixel in a given low-resolution facial image, we can estimate optimal coefficients for a linear combination of prototypes of shape and those that of texture by solving least square minimizations. Then high-resolution facial image can be obtained by using the optimal coefficients for linear combination of the high-resolution prototypes. In addition, a recursive error back-projection procedure is applied to improve the reconstruction accuracy of high-resolution facial image. The encouraging results of the proposed method show that our method can be used to improve the performance of the face recognition by applying our method to reconstruct high-resolution facial images from low-resolution images captured at a distance.

Resonance Characteristics and Radiation Characteristics of a Spherical Patch on a Dielectric Sphere (구형 유전체 위에 있는 구형 패치의 공진 특성과 방사 특성)

  • Jeong, Yi-Ru;Hong, Ic-Pyo;Lee, Myung-Gun;Chun, Hueng-Jae;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.4
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    • pp.515-523
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    • 2012
  • In this paper, the resonance characteristics and radiation characteristics of a spherical patch on a dielectric sphere are analyzed. Resonance characteristics can be obtained from the resonant frequency and the quality factor. Radiation characteristics can be also analyzed from the E-field in the far region. In order to calculate these parameters, spectral domain analysis method is applied. Algebraic equation can be obtained in spectral domain through Vector Legendre transform pair and Galerkin's method. So, efficient calculation is possible numerically. It is investigated that radius, curvature of a spherical patch, and dielectric constant of a dielectric sphere have an effect on characteristics of a spherical patch.

Remote Field Eddy Current Testing for Detection of Stress Corrosion Cracks in Gas Transmission Pipelines (가스 파이프라인 상의 압력 부식에 의한 흠집 검사를 위한 원격 와전류 탐상 기술)

  • Kim, Dae-Won
    • Journal of the Korean Magnetics Society
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    • v.16 no.6
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    • pp.305-308
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    • 2006
  • Magnetic flux leakage (MFL) pigs are traditionally used for the detection of gross corrosion on steel pipelines used for the transmission of natural gas. Alternative nondestructive evaluation (NDE) modalities are required for the detection of stress corrosion cracking (SCC) which tends to exist in colonies oriented axially along the length of the pipeline. This paper describes the use of multiphase rotating magnetic fields in the remote region of the probe as a possible SCC detection mechanism. Details of a prototype pig and test rig are given and the challenges associated with the finite element modeling of the device are discussed. Initial experimental results show that this novel NDE modality is sensitive to axially oriented tight cracks.

Performance Analysis of Face Recognition by Face Image resolutions using CNN without Backpropergation and LDA (역전파가 제거된 CNN과 LDA를 이용한 얼굴 영상 해상도별 얼굴 인식률 분석)

  • Moon, Hae-Min;Park, Jin-Won;Pan, Sung Bum
    • Smart Media Journal
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    • v.5 no.1
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    • pp.24-29
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    • 2016
  • To satisfy the needs of high-level intelligent surveillance system, it shall be able to extract objects and classify to identify precise information on the object. The representative method to identify one's identity is face recognition that is caused a change in the recognition rate according to environmental factors such as illumination, background and angle of camera. In this paper, we analyze the robust face recognition of face image by changing the distance through a variety of experiments. The experiment was conducted by real face images of 1m to 5m. The method of face recognition based on Linear Discriminant Analysis show the best performance in average 75.4% when a large number of face images per one person is used for training. However, face recognition based on Convolution Neural Network show the best performance in average 69.8% when the number of face images per one person is less than five. In addition, rate of low resolution face recognition decrease rapidly when the size of the face image is smaller than $15{\times}15$.

Aeroacoustic Analysis of UAM Aircraft in Ground Effect for Take-off/Landing on Vertiport (버티포트 이착륙을 고려한 지면 효과를 받는 UAM 항공기에 대한 공력소음 해석 연구)

  • Jin-Yong Yang;Hyeok-Jin Lee;Min-Je Kang;Eunmin Kim;Rho-Shin Myong;Hakjin Lee
    • Journal of Aerospace System Engineering
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    • v.17 no.2
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    • pp.26-37
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    • 2023
  • Urban air mobility (UAM) is being developed as part of the next-generation aircraft, which could be a viable solution to entrenched problems of urban traffic congestion and environmental pollution. A new airport platform called vertiport as a space where UAM can take off and land vertically is also being introduced. Noise regulations for UAM will be strict due to its operation in a highly populated urban area. Ground effects caused by vertiport can directly affect aerodynamic forces and noise characteristics of UAM. In this study, ground effects of vertiport on aerodynamic loads, vorticity field, and far-field noise were analyzed using Lattice-Boltzmann Method (LBM) simulation and Ffowcs Williams and Hawkings (FW-H) acoustic analogy with a permeable surface method.

Sequential Use of COMSOL Multiphysics® and PyLith for Poroelastic Modeling of Fluid Injection and Induced Earthquakes (COMSOL Multiphysics®와 PyLith의 순차 적용을 통한 지중 유체 주입과 유발지진 공탄성 수치 모사 기법 연구)

  • Jang, Chan-Hee;Kim, Hyun Na;So, Byung-Dal
    • The Journal of Engineering Geology
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    • v.32 no.4
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    • pp.643-659
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    • 2022
  • Geologic sequestration technologies such as CCS (carbon capture and storage), EGS (enhanced geothermal systems), and EOR (enhanced oil recovery) have been widely implemented in recent years, prompting evaluation of the mechanical stability of storage sites. As fluid injection can stimulate mechanical instability in storage layers by perturbing the stress state and pore pressure, poroelastic models considering various injection scenarios are required. In this study, we calculate the pore pressure, stress distribution, and vertical displacement along a surface using commercial finite element software (COMSOL); fault slips are subsequently simulated using PyLith, an open-source finite element software. The displacement fields, are obtained from PyLith is transferred back to COMSOL to determine changes in coseismic stresses and surface displacements. Our sequential use of COMSOL-PyLith-COMSOL for poroelastic modeling of fluid-injection and induced-earthquakes reveals large variations of pore pressure, vertical displacement, and Coulomb failure stress change during injection periods. On the other hand, the residual stress diffuses into the remote field after injection stops. This flow pattern suggests the necessity of numerical modeling and long-term monitoring, even after injection has stopped. We found that the time at which the Coulomb failure stress reaches the critical point greatly varies with the hydraulic and poroelastic properties (e.g., permeability and Biot-Willis coefficient) of the fault and injection layer. We suggest that an understanding of the detailed physical properties of the surrounding layer is important in selecting the injection site. Our numerical results showing the surface displacement and deviatoric stress distribution with different amounts of fault slip highlight the need to test more variable fault slip scenarios.

Far Distance Face Detection from The Interest Areas Expansion based on User Eye-tracking Information (시선 응시 점 기반의 관심영역 확장을 통한 원 거리 얼굴 검출)

  • Park, Heesun;Hong, Jangpyo;Kim, Sangyeol;Jang, Young-Min;Kim, Cheol-Su;Lee, Minho
    • 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.

Comparison of the sound source localization methods appropriate for a compact microphone array (소형 마이크로폰 배열에 적용 가능한 음원 위치 추정법 비교)

  • Jung, In-Jee;Ih, Jeong-Guon
    • The Journal of the Acoustical Society of Korea
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    • v.39 no.1
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    • pp.47-56
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    • 2020
  • The sound source localization technique has various application fields in the era of internet-of-things, for which the probe size becomes critical. The localization methods using the acoustic intensity vector has an advantage of downsizing the layout of the array owing to a small finite-difference error for the short distance between adjacent microphones. In this paper, the acoustic intensity vector and the Time Difference of Arrival (TDoA) method are compared in the viewpoint of the localization error in the far-field. The comparison is made according to the change of spacing between adjacent microphones of the three-dimensional microphone array arranged in a tetrahedral shape. An additional test is conducted in the reverberant field by varying the reverberation time to verify the effectiveness of the methods applied to the actual environments. For estimating the TDoA, the Generalized Cross Correlation-Phase transform (GCC-PHAT) algorithm is adopted in the computation. It is found that the mean localization error of the acoustic intensimetry is 2.9° and that of the GCC-PHAT is 7.3° for T60 = 0.4 s, while the error increases as 9.9°, 13.0° for T60 = 1.0 s, respectively. The data supports that a compact array employing the acoustic intensimetry can localize of the sound source in the actual environment with the moderate reflection conditions.