• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.367-370
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• 2001

본 논문에서는 영상 합성을 위해 실시간으로 움직임 물체를 추출하고 움직임 물체의 홀이나 외곽선의 손실을 최소화하고 복원하는 알고리즘을 제안한다. 움직임은 기준영상과 현재 입력된 영상의 차이를 계산함으로써 검출 된다. 따라서 여기서 적당한 기준 영상과 검출 문턱치 방법의 선택이 필요하게 된다. 몇 가지 문턱치 선택 방법들이 연구되었나, 본 논문에서는 회귀적인 문턱치들을 이용한다. 그레이 영상을 통해 구해진 영역에서 칼라 값의 비교를 통해 손실된 영역을 복구하고 최종 실루엣 영상을 얻는다. 얻어진 움직임 물체의 실루엣 영상은 영상 합성에 이용한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.789-794
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• 2017

Subthreshold current model is presented using analytical potential distribution of junctionless cylindrical surrounding-gate (CSG) MOSFET and threshold voltage shift is analyzed by this model. Junctionless CSG MOSFET is significantly outstanding for controllability of gate to carrier flow due to channel surrounded by gate. Poisson's equation is solved using parabolic potential distribution, and subthreshold current model is suggested by center potential distribution derived. Threshold voltage is defined as gate voltage corresponding to subthreshold current of $0.1{\mu}A$, and compared with result of two dimensional simulation. Since results between this model and 2D simulation are good agreement, threshold voltage shift is investigated for channel dimension and doping concentration of junctionless CSG MOSFET. As a result, threshold voltage shift increases for large channel radius and oxide thickness. It is resultingly shown that threshold voltage increases for the large difference of doping concentrations between source/drain and channel.

• Journal of the Korea society of information convergence
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• v.7 no.2
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• pp.7-12
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• 2014

Many filters are made in order to dectect the accurate signal. The performance of the filter is evaluated as to remove the noise effectively. It is necessary to determine the threshold value for the accurate evaluation of the filter effectively. In this study, we investigated the optimization of the threshold value. It was used for the triangular wave signal and the power supply noise. SNR change according to the number of samples was studied. As the number of samples increases, SNR saw also stabilizde.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.9
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• pp.729-737
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• 1990

This paper presents a new method of multilevel estimation of dithered images. A dithered picture, a two-tone picture which gives the illusion of picture with many shades of gray, is obtained by comparing the gray-level picture which gives the illusion of picture with a position-dependent threshold. When the intensity of a picture element exeeds the threshold it is classified as white: otherwise it is black. In the new estimation scheme, the simulation results show the SNR of the new method is improved 0.7dB compared with the old method. And we propose a new progressive image transmission by employing thie method.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1641-1644
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• 2004

3차원 볼륨데이터에서 분할 대상영역의 밝기 값이 다양하면서 밝기 값이 유사한 영역과 인접한 경우 3차원 영역확장(region growing) 방법을 사용하여 영역을 분할하기 위해서는 영역확장의 중요한 요인인 동질성 기준 값의 적절한 선택이 요구된다. 본 논문에서는 영역 복셀(voxel)의 1차 미분 값의 크기인 기울기 크기(gradient magnitude)만으로 영역의 경계를 찾기가 쉽지않은 대상의 분할을 위해 볼륨데이터의 지역적인 밝기 값의 변화의 특징을 고려하면서 분할 대상영역의 복셀의 2차 미분(second partial derivation)을 행렬의 요소(element)로 갖는 Hessian 행렬의 고유치(eigenvalue)를 영역확장의 문턱치 결정에 이용하였다. 제안한 알고리즘은 3차원 영역확장의 결과에 가장 큰 영향을 미치는 적절한 문턱치의 선택으로 대상영역의 분할을 성공적으로 수행하여 3차원 영역확장의 단점을 보완하였다.

• The KIPS Transactions:PartB
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• v.17B no.5
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• pp.363-374
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• 2010

In this paper, we propose the method for extracting Homogeneity Threshold($H_T$) and for segmenting homogeneous regions by USRG(Unseeded Region Growing) with $H_T$. The $H_T$ is a criterion to distinguish homogeneity in neighbor pixels and is computed automatically from the original image by proposed method. Theoretical background for proposed method is based on the Otsu's single level threshold method. The method is used to divide a small local part of original image int o two classes and the sum($\sigma_c$) of standard deviations for the classes to satisfy special conditions for distinguishing as different regions from each other is used to compute $H_T$. To find validity for proposed method, we compare the original image with the image that is regenerated with only the segmented homogeneous regions and show up the fact that the difference between two images is not exist visually and also present the steps to regenerate the image in order the size of segmented homogeneous regions and in order the intensity that includes pixels. Also, we show up the validity of proposed method with various results that is segmented using the homogeneity thresholds($H^*_T$) that is added a coefficient ${\alpha}$ for adjusting scope of $H_T$. We expect that the proposed method can be applied in various fields such as visualization and animation of natural image, anatomy and biology and so on.

• The Journal of the Acoustical Society of Korea
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• v.22 no.7
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• pp.539-544
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• 2003

This paper describes how to reduce the effect of an occupation threshold by that the transform of mixture components of HMM parameters is controlled in hierarchical tree structure to prevent from over-adaptation. To reduce correlations between data elements and to remove elements with less variance, we employ PCA (Principal component analysis) and ICA (independent component analysis) that would give as good a representation as possible, and decline the effect of over-adaptation. When we set lower occupation threshold and increase the number of transformation function, ordinary MLLR adaptation algorithm represents lower recognition rate than SI models, whereas the proposed MLLR adaptation algorithm represents the improvement of over 2% for the word recognition rate as compared to performance of SI models.

• Korean Journal of Optics and Photonics
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• v.10 no.6
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• pp.487-493
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• 1999

In this paper, we studied the characteristics of a soliton coupler using a bent nonlinear waveguide. The bent soliton coupler has very ,harp switching characteristic like the conventional soliton coupler due to the threshold effect of soliton emi,sion from the nonlinear waveguide. By using the bent structure, we can reduce the threshold power for the soliton emission. We consider the saturation effect of nonlinearity and the loss in the medium for more accurate and practical numerical analysis in wave propagation through the bent soliton coupler. The simulation results show that the consideration of the saturation effect and the ]os~ may be very important in the analyses and design of the nonlinear waveguide devices. The bent structure is useful for the emission of the spatial soliton with the low threshold power, when we consider the saturation and the loss effect. ffect.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.79-83
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• 2004

The purpose of ATM traffic management is to protect the network using minimum resources and guarantee the requred QoS and also it is desirable to provide fairness between input channels. In this paper, we propose the TBBM(threshold based buffer management) algorithm to improve fairness between input channels and utilization of ATM networks. TBBM algorithm controls output cell rate dynamically based on threshold. The result shows that the required bandwidth of the TBBM algorithm is 14.3% lower in audio traffic and 41.8% lower in video traffic than that of theoretically calculated equivalent capacity method. and also reveals that the TBBM algorithm provide improved CLR fairness between input channels

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6C
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• pp.532-540
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• 2005

In this paper, a sequential detection scheme is proposed as a combination of a novel weak-signal and a locally optimum(LO) detection schemes. In Part 1, we propose a novel sequential detection scheme for weak signals and show some interesting threshold properties and examples. In Part 2, the performance of the proposed sequential detection scheme is compared with that of the fixed sample size(FSS) test, sequential probability ratio test (SPRT), and truncated sequential probability ratio test(TSPRT).