• 한국전자파학회논문지
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• 제14권10호
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• pp.1096-1103
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• 2003

본 논문에서는 시간영역 PMCHW 적분방정식을 이용하여 3차원 유전체로부터의 전자기 과도 응답을 해석하기 위한 새로운 해법을 제안한다. 이를 위하여 공간 및 시간 시험 과정으로 분리한 갤러킨 방법을 적용한다. 3차원 임의 형태의 유전체 표면을 삼각형으로 분할한 다음, 공간에 대한 등가전류의 전개 및 시험 함수로서 삼각형 벡터 함수를 사용한다. 시간영역의 미지 계수를 라게르 함수로부터 유도된 기저함수로 근사하며, 이 함수를 시간영역의 시험함수로도 사용한다. 제안된 방법에 의하여 계산된 유전체의 등가전류 및 원거리장의 수치 결과들을 보인다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.490-495
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• 2009

An approach to 3D visualization of multiple sound sources has been developed with the application of a moving array technique. Frequency-domain beamforming algorithm is used to generate a beam power map and the sound source is modeled as a point source. When a conventional delay and sum beamformer is used, it is considered that 2D distribution of sensors leads to have deficiency in spatial resolution along a measurement distance. The goal of moving an array in this study is to form 3D array aperture surrounding multiple sound sources so that the improved spatial resolution in a virtual space can be expected. Numerical simulation was made to examine source localization capabilities of various shapes of array. The 3D beam power maps of hemispherical and spherical distribution are found to have very sharp resolution. For experiments, two sound sources were placed in the middle of defined virtual space and arc-shaped line array was rotated around the sources. It is observed that spherical array show the most accurate determination of multiple sources' positions.

• 한국소음진동공학회논문집
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• 제19권9호
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• pp.907-914
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• 2009

An approach to 3D visualization of multiple sound sources has been developed with the application of a moving array technique. Frequency domain beamforming algorithm is used to generate a beam power map and the sound source is modeled as a point source. When a conventional delay and sum beamformer is used, it is considered that 2D distribution of sensors leads to have deficiency in spatial resolution along a measurement distance. The goal of moving an array in this study is to form 3D array aperture surrounding multiple sound sources so that the improved spatial resolution in a virtual space can be expected. Numerical simulation was made to examine source localization capabilities of various shapes of array. The 3D beam power maps of hemispherical and spherical distribution are found to have very sharp resolution. For experiments, several sound sources were placed in the middle of defined virtual space and arc-shaped line array was rotated around the sources. It is observed that spherical array shows the most accurate determination of multiple sources' positions.

• ETRI Journal
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• 제39권5호
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• pp.672-682
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• 2017

Video compression exploits statistical, spatial, and temporal redundancy, as well as transform and quantization. In particular, the transform in a frequency domain plays a major role in energy compaction of spatial domain data into frequency domain data. The high efficient video coding standard uses the type-II discrete cosine transform (DCT-II) and type-VII discrete sine transform (DST-VII) to improve the coding efficiency of residual data. However, the DST-VII is applied only to the Intra $4{\times}4$ residual block because it yields relatively small gains in the larger block than in the $4{\times}4$ block. In this study, after rearranging the data of the residual block, we apply the DST-VII to the inter-residual block to achieve coding gain. The rearrangement of the residual block data is similar to the arrangement of the basis vector with a the lowest frequency component of the DST-VII. Experimental results show that the proposed method reduces the luma-chroma (Cb+Cr) BD rates by approximately 0.23% to 0.22%, 0.44% to 0.58%, and 0.46% to 0.65% for the random access, low delay B, and low delay P configurations, respectively.

• 한국정보통신학회논문지
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• 제7권8호
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• pp.1684-1690
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• 2003

본 논문에서는 H.263 부호기에서 적정 화질과 일정한 전송율을 유지하는 양자화 변수 추정을 위한 퍼지 제어기를 제안하였다. 퍼지화 방법으로는 Mamdani 방법을 이용하며, 역퍼지화는 무게중심법을 이용하였다. 움직임 벡터에 따른 시간적 특성을 추정할 때 공간영역에서 분산과 엔트로피는 시각적 특성과 상관관계가 있다. 따라서 퍼지 입력변수로 영상의 분산값, 엔트로피 및 움직임 벡터를 이용하였다. 퍼지 소속함수를 유도하고, 시각적 특성에 적합한 퍼지감도를 결정하였으며, FAM 뱅크를 설계하였다. 실제 동영상 압축에 퍼지 규칙을 적용하였으며, 퍼지 양자화를 이용하여 효율적인 율제어와 최적의 비트할당 및 주관적 화질 특성이 유지되는 결과를 얻었다.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.127-136
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• 2021

Real-time human recognition is a challenging task, as the images are captured in an unconstrained environment with different poses, makeups, and styles. This limitation is addressed by generating several facial images with poses, makeup, and styles with a single reference image of a person using Generative Adversarial Networks (GAN). In this paper, we propose deep learning-based human recognition using integration of GAN and Spatial Domain Techniques. A novel concept of human recognition based on face depiction approach by generating several dissimilar face images from single reference face image using Domain Transfer Generative Adversarial Networks (DT-GAN) combined with feature extraction techniques such as Local Binary Pattern (LBP) and Histogram is deliberated. The Euclidean Distance (ED) is used in the matching section for comparison of features to test the performance of the method. A database of millions of people with a single reference face image per person, instead of multiple reference face images, is created and saved on the centralized server, which helps to reduce memory load on the centralized server. It is noticed that the recognition accuracy is 100% for smaller size datasets and a little less accuracy for larger size datasets and also, results are compared with present methods to show the superiority of proposed method.

• 정보보호학회논문지
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• 제15권2호
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• pp.113-122
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• 2005

본 논문에서는 악의적인 공격에는 워터마크가 쉽게 깨어지고 비악의적인 공격에는 워터마크가 쉽게 깨어지지 않도록 하는 투 가지 목적을 동시에 만족시키기 위한 다중 워터마킹 알고리즘을 제안한다. Discrete Wavelet Transform(DWT)의 계수를 이용해 이미지를 인증하는 기법으로, 워터마크로 사용될 이진 이미지와 LL3 영역에서 추출된 특징을 조합하여 이미지에 삽입될 정보를 생성한다 이미지의 공간영역과 주파수영역에 정보를 다중으로 삽입하여 공간영역에서 일어날 수 있는 악의적인 공격에 대응할 뿐만 아니라 주파수영역에서의 blurring, sharpening 및 JPEG 압축과 간은 비 악의적인 공격을 허용하는 기법이다. 공간영역에서는 이미지 블록의 모든 픽셀의 Least Significant Bit(LSB)에 정보를 삽입하고, 주파수영역에서는 삽입할 정보에 따라 LH2와 HL2의 계수를 조절하므로 정보를 삽입하게 된다.

• 한국공간구조학회논문집
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• 제2권1호
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• pp.67-73
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• 2002

Measurement of fluctuating pressure by tube system is carefully designed due to the organ-pipe resonance. It is necessary to correct the pressure before analysis. The three method for correction the distortion fluctuation pressure short tube length and the frequency response functions and insert a restrictor in the tube to increase the damping. The first method is useful when the tube length is short. In second method, the distorted signal through the tubing transformed into the frequency domain, dividing by transfer function and inverse fourier transforming back into the time domain gives the required pressure signal. In this paper three types of tubing which have different length of 100cm, 150cm, 200cm were experimented the distorted signal and correct the distortion signal

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.266-269
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• 2003

In this work, a new formulation is presented for analyzing the transient electromagnetic response from wire antennas using the time-domain integral equation. The solution method is based on the Galerkin's method that involves separate spatial and temporal testing procedures. Piecewise triangle basis functions have been used for spatial expansion functions for arbitrarily shaped wire structures. The time-domain variation is approximated by a set of orthonormal basis functions that are derived from the Laguerre polynomials. The method presented in this paper results in very stable transient responses from wire antennas.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1320-1326
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• 2002

In a one-dimensional heat conduction domain with heated and insulated walls, an integral approach is proposed to estimate time-dependent boundary heat flux without internal measurements. It is assumed that the expression of the heat flux is not known a priori. Hence, the present inverse heat conduction problem is classified as a function estimation problem. The spatial temperature distribution is approximated as a third-order polynomial of position, whose four coefficients are determined from the heat fluxes and the temperatures at both ends at each measurement. After integrating the heat conduction equation over spatial and time domain, respectively, a simple and non-iterative recursive equation to estimate the time-dependent boundary heat flux is derived. Several examples are introduced to show the effectiveness of the present approach.