• Title/Summary/Keyword: 가우스 함수

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A Study on the Analysis of the Error in Photometric Stereo Method Caused by the General-purpose Lighting Environment (測光立體視法에서 범용조명원에 기인한 오차 해석에 관한 연구)

  • Kim, Tae-Eun;Chang, Tae-Gyu;Choi, Jong-Soo
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.11
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    • pp.53-62
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    • 1994
  • This paper presents a new approach of analyzing errors resulting from nonideal general-purpose lighting environment when the Photometric Stereo Method (PSM) is applied to estimate the surface-orientation of a three-dimensional object. The approach introduces the explicit modeling of the lighting environment including a circular-disk type irradiance object plane and the direct simulation of the error distribution with the model. The light source is modeled as a point source that has a certain amount of beam angle, and the luminance distribution on the irradiance plane is modeled as a Gaussian function with different deviation values. A simulation algorithm is devised to estimate the light source orientation computing the average luminance intensities obtained from the irradiance object planes positioned in three different orientations. The effect of the nonideal lighting model is directly reflected in such simulation, because of the analogy between the PSM and the proposed algorithm. With an instrumental tool designed to provide arbitrary orientations of the object plane at the origin of the coordinate system, experiment can be performed in a systematic way for the error analysis and compensation. Simulations are performed to find out the error distribution by widely varying the light model and the orientation set of the object plane. The simulation results are compared with those of the experiment performed in the same way as the simulation. It is confirmed from the experiment that a fair amount of errors is due to the erroneous effect of the general-purpose lighting environment.

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Improvement of the PFCM(Possibilistic Fuzzy C-Means) Clustering Method (PFCM 클러스터링 기법의 개선)

  • Heo, Gyeong-Yong;Choe, Se-Woon;Woo, Young-Woon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.1
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    • pp.177-185
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    • 2009
  • Cluster analysis or clustering is a kind of unsupervised learning method in which a set of data points is divided into a given number of homogeneous groups. Fuzzy clustering method, one of the most popular clustering method, allows a point to belong to all the clusters with different degrees, so produces more intuitive and natural clusters than hard clustering method does. Even more some of fuzzy clustering variants have noise-immunity. In this paper, we improved the Possibilistic Fuzzy C-Means (PFCM), which generates a membership matrix as well as a typicality matrix, using Gath-Geva (GG) method. The proposed method has a focus on the boundaries of clusters, which is different from most of the other methods having a focus on the centers of clusters. The generated membership values are suitable for the classification-type applications. As the typicality values generated from the algorithm have a similar distribution with the values of density function of Gaussian distribution, it is useful for Gaussian-type density estimation. Even more GG method can handle the clusters having different numbers of data points, which the other well-known method by Gustafson and Kessel can not. All of these points are obvious in the experimental results.

Exploration of underground utilities using method predicting an anomaly (이상대 판정기법을 활용한 지하매설물 탐사)

  • Ryu, Hee-Hwan;Kim, Kyoung-Yul;Lee, Kang-Ryel;Lee, Dae-Soo;Cho, Gye-Chun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.3
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    • pp.205-214
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    • 2015
  • Rapid urbanization and industrialization have caused increased demand for underground structures such as cable, and other utility tunnels. Recently, it has become very difficult to construct new underground structures in downtown areas because of civil complaints, and engineering problems related to insufficient information about existing underground structures, cable tunnels in particular. This lack of information about the location and direction-of-travel of cable tunnels is causing many problems. To solve these problems, this study was focused on the use of geophysical exploration of the ground in a way that is theoretically, different from previous electrical resistivity surveys. An electric field analysis was performed on the ground with cable tunnels using Gauss' law and the Laplace equation. The electrical resistivity equation, which is a function of the cable tunnel direction, the cable tunnel location, and the electrical conductivity of the cable tunnel, can be obtained through electrical field analysis. A field test was performed for the verification of this theoretical approach. A field test results provided meaningful data.

Human Motion Tracking by Combining View-based and Model-based Methods for Monocular Video Sequences (하나의 비디오 입력을 위한 모습 기반법과 모델 사용법을 혼용한 사람 동작 추적법)

  • Park, Ji-Hun;Park, Sang-Ho;Aggarwal, J.K.
    • The KIPS Transactions:PartB
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    • v.10B no.6
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    • pp.657-664
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    • 2003
  • Reliable tracking of moving humans is essential to motion estimation, video surveillance and human-computer interface. This paper presents a new approach to human motion tracking that combines appearance-based and model-based techniques. Monocular color video is processed at both pixel level and object level. At the pixel level, a Gaussian mixture model is used to train and classily individual pixel colors. At the object level, a 3D human body model projected on a 2D image plane is used to fit the image data. Our method does not use inverse kinematics due to the singularity problem. While many others use stochastic sampling for model-based motion tracking, our method is purely dependent on nonlinear programming. We convert the human motion tracking problem into a nonlinear programming problem. A cost function for parameter optimization is used to estimate the degree of the overlapping between the foreground input image silhouette and a projected 3D model body silhouette. The overlapping is computed using computational geometry by converting a set of pixels from the image domain to a polygon in the real projection plane domain. Our method is used to recognize various human motions. Motion tracking results from video sequences are very encouraging.

Electronic Structure of Iron and Molybdenum in $Li_2FeMoO_4Cl$ and Its Crystal Symmetry ($Li_2FeMoO_4Cl$의 결정구조와 Fe 및 Mo의 전자구조 연구)

  • Choy, Jin-Ho;Park, Nam-Gyu;Chang, Soon-Ho;Park, Hyung-Ho
    • Journal of the Korean Chemical Society
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    • v.39 no.6
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    • pp.446-452
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    • 1995
  • Lithium intercalates, $Li_xFeMoO_4Cl$ ($1{\leq}X{\leq}2$) prepared by electrochemical lithiation of $FeMoO_4Cl$ crystallizes in monoclinic structure for all x values as revealed by x-ray diffraction and galvanostatic discharge experiments. According to the x-ray photoelectron spectroscopic study, Fe(III) is at first reduced to Fe(II) upon lithium intercalation with the x domain of $0{\leq}X{\leq}1$, where the crystal symmetry is changed from tetragonal to monoclinic. On the other hand, Mo(VI) is reduced to lower valent state upon further lithium intercalation ($1{\leq}X{\leq}2$), where no crystal symmetry transformation and reduction of Fe(II) to lower valent state are observed. The Mo 3d spectrum for $Li_2FeMoO_4Cl$ appears as a complex shape, but can be deconvoluted into the three sets of the doublet on the basis of Gaussian function, those which correspond to Mo(VI), Mo(V) and Mo(IV) states, respectively. The mixed valent states of molybdenum after further lithiation may be due to a competitive reaction between the formation of Mo(V) and its disproportionation to Mo(IV) and Mo(VI).

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Error Performance Analysis of Digital Radio Signals in an Electromagnetic Interference (EMI) Environment of Impulsive Noise Plus Disturbance (임펄스 잡음과 방해파에 의한 전자파 장해(EMI) 환경하에서의 디지털 무선통신 신호의 오율해석)

  • Cho, Sung-Eon;Leem, Kill-Yong;Cho, Sung-Joon;Lee, Jin
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.6 no.3
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    • pp.36-54
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    • 1995
  • The error performance of digital radio signals (i.e., M-ary PSK signal, DQPSK signal, MSK signal, GMSK signal) interfered by impulsive noise and electromagnetic interference (EMI) is analyzed and discussed. In analysis at first, the error rate equations have been derived in an electromagnetic interference plus impulsive noise environment. And then, the error performance has been evaluated and shown in figures as a function of carrier-to-noise ratio, carrier-to-interference ratio, impu- lsive index, gaussian noise to impulsive noise power ratio, and interference index to measure the amount of error degradation in digital radio signals. From the obtained results we have known that in the presence of m-distributed tone interference plus inpulsive noise, the more significant the electromagnetic interference amplitude varies, the more significant performance degradation is produced. The listing the digital radio signals from the most degraded to the least is that DQPSK, GMSK, QPSK and MSK signal. In the constant amplitude tone interference plus impulsive noise environment, the effect of in- terference nearly disappears over about 20dB in CIR. The effect of constant tone interference on error rate performance is reduced more remarkably in the region from 10dB to 15dB in CIR. In both enviroments of m-distributed tone interference and constant amplitude tone interference, the more electromagnetic interference amplitude varies and CIR increases, the more error perfor- mance is improved. But it is found out that the performance can not be improved significantly even the electromagnetic interference becomes weak. This describes that the impulsive noise affects dominantly to the performance degradation.

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Conduction Path Dependent Threshold Voltage for the Ratio of Top and Bottom Oxide Thickness of Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET의 상하단 산화막 두께비에 따른 전도중심에 대한 문턱전압 의존성)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.11
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    • pp.2709-2714
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    • 2014
  • This paper has analyzed the change of threshold voltage and conduction path for the ratio of top and bottom gate oxide thickness of asymmetric double gate MOSFET. The asymmetric double gate MOSFET has the advantage that the factor to be able to control the current in the subthreshold region increases. The analytical potential distribution is derived from Poisson's equation to analyze the threshold voltage and conduction path for the ratio of top and bottom gate oxide thickness. The Gaussian distribution function is used as charge distribution. This analytical potential distribution is used to derive off-current and subthreshold swing. By observing the results of threshold voltage and conduction path with parameters of bottom gate voltage, channel length and thickness, projected range and standard projected deviation, the threshold voltage greatly changed for the ratio of top and bottom gate oxide thickness. The threshold voltage changed for the ratio of channel length and thickness, not the absolute values of those, and it increased when conduction path moved toward top gate. The threshold voltage and conduction path changed more greatly for projected range than standard projected deviation.

Dynamics of the River Plume (하천수 플룸 퍼짐의 동력학적 연구)

  • Yu, Hong-Sun;Lee, Jun;Shin, Jang-Ryong
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.6 no.4
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    • pp.413-420
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    • 1994
  • Dynamics of the river plume is a very complicated non-linear problem with the free boundary changing in time and space. Mixing with the ambient water through the boundary makes the problem more complicated. In this paper we reduced 3-dimensional problem into 1-dimensional one by using the integral analysis method. Basic equations have been integrated over the lateral and vertical variations. For these integrations we adopted the well-established assumption that the flow-axis component of plume velocity and the density difference of the plume with the ambient water have Gaussian distributions in directions which are perpendicular to the flow-axis of the plume. We also used the result of our previous study on the lateral spreading velocity of the plume derived under the same assumption. And entrainment was included as a mixing process. The resultant 1-dimensional equations were solved by Runge-Kutta numerical method. Consequently, comparatively easy method of numerical analysis is presented for the 3-dimensional river plume. The method can also be used for the analysis of the thermal plume of cooling water of power plants.

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