• 제목/요약/키워드: Level set methods

검색결과 1,050건 처리시간 0.024초

정보통신 표준화 지수측정 모형 개발 연구

  • 이승환;박명철;이상우;구경철
    • 한국경영과학회:학술대회논문집
    • /
    • 한국경영과학회 2003년도 추계학술대회 및 정기총회
    • /
    • pp.103-106
    • /
    • 2003
  • This paper proposes an index model which can measure the degree of standardization in the Korean ICT field. We first classified ICT sector into 14 sub-sectors. Then for each sub-sector, we considered a set of important determinants to measure the level of standardization, and constructed a linear equation using this set of determinants. Finally we estimated the relative degree of importance of each determinant using the AHP methodology. The proposed model found that overall level of standardization in the Korean ICT industry is relatively low, and "IMT-2000 technology" and "computer network technology" among 14 sub-sectors are highly standardized sub-sectors, Finally, the validity of the proposed model was also partially proved using two different methods, holistic and historical approach.

  • PDF

A FAST NUMERICAL METHOD FOR SOLVING A REGULARIZED PROBLEM ASSOCIATED WITH OBSTACLE PROBLEMS

  • Yuan, Daming;Li, Xi;Lei, Chengfeng
    • 대한수학회지
    • /
    • 제49권5호
    • /
    • pp.893-905
    • /
    • 2012
  • Kirsi Majava and Xue-Cheng Tai [12] proposed a modified level set method for solving a free boundary problem associated with unilateral obstacle problems. The proximal bundle method and gradient method were applied to solve the nonsmooth minimization problems and the regularized problem, respectively. In this paper, we extend this approach to solve the bilateral obstacle problems and employ Rung-Kutta method to solve the initial value problem derived from the regularized problem. Numerical experiments are presented to verify the efficiency of the methods.

함수복잡도를 이용한 큐브선택과 이단계 리드뮬러표현의 최소화 (Cube selection using function complexity and minimizatio of two-level reed-muller expressions)

  • Lee, Gueesang
    • 전자공학회논문지A
    • /
    • 제32A권6호
    • /
    • pp.104-110
    • /
    • 1995
  • In this paper, an effective method for the minimization of two-level Reed-muller expressions by cube selection whcih considers functional complexity is presented. In contrast to the previous methods which use Xlinking operations to join two cubes for minimizatio, the cube selection method tries to select cubes one at a time until they cover the ON-set of the given function. This method works for most benchmark circuits, but for parity-type functions it shows power performance. To solve this problem, a cost function which computes the functional complexity instead of only the size of ON-set of the function is used. Therefore the optimization is performed considering how the trun minterms are grouped together so that they can be realized by only a small number of cubes. In other words, it considers how the function is changed and how the change affects the next optimization step. Experimental results shows better performance in many cases including parity-type functions compared to pervious results.

  • PDF

Bi-Level HMM을 이용한 효율적인 음성구간 검출 방법 (An Efficient Voice Activity Detection Method using Bi-Level HMM)

  • 장광우;정문호
    • 한국전자통신학회논문지
    • /
    • 제10권8호
    • /
    • pp.901-906
    • /
    • 2015
  • 본 논문에서는 Bi-Level HMM을 이용한 음성구간 검출 방법을 제안하였다. 기존의 음성 구간 검출법은 짧은 상태변화 오류(Burst Clipping)를 제거하기 위하여 별도의 후처리 과정을 거치든가, 규칙 기반 지연 프레임을 설정해야만 한다. 이러한 문제에 대처하기 위하여 기존의 HMM 모델에 상태 계층을 추가한 Bi-Level HMM을 이용하여 음성구간 판정을 위해 음성상태의 사후 확률비를 이용하였다. 사람의 청각특성을 고려한 MFCC를 특징치로 하여, 다양한 SNR의 음성 데이터에 대한 평가지표를 활용한 실험을 수행하여 기존의 음성상태 분류법보다 우수한 결과를 얻을 수 있었다.

터널 순응휘도와 경계부 휘도의 관계 연구 (Relationship between Adaptation Luminance and Threshold Zone Luminance for Vehicular Traffic Tunnels)

  • 조원범;정준화
    • 한국도로학회논문집
    • /
    • 제16권3호
    • /
    • pp.85-99
    • /
    • 2014
  • PURPOSES : This study has been performed with the objective to determine threshold zone luminance of adaptation luminance by target safety level in a vehicular traffic tunnel with design speed set at 100km/h. METHODS : The study made a miniature capable of portraying changes in luminance distribution within $2{\times}10^{\circ}$ conical field of view of the driver approaching to the tunnel for the test. Test conditions were set based on justifications for CIE 88-1990's threshold zone luminance used as a reference by domestic tunnel light standards (KS C 3703 : 2010). Luminance contrast of object background and object is 23%, object presentation duration is 0.5 seconds, and size of the object background is $7.3{\times}11.5m^2$ RESULTS : Threshold zone luminance was set within adaptation luminance of $100{\sim}3,000cd/m^2$. Adaptation luminance and threshold zone luminance based on 50%, 75% and 90% target safety level all showed a relatively high linear relationship. According to findings in the study, it is not appropriate to specify the relationship between adaptation luminance and threshold zone luminance as luminance ratio. Rather, direct utilization of the linear relationship gained from the study findings appears to be the better solution. CONCLUSIONS : Findings of this study may be used to determine operation of threshold zone luminance based on target safety level. However, a proper verification and validity of test results are required. Furthermore, a study to determine proper threshold zone luminance level considering target safety level reviewed in this study and various decision-making factors such as economic conditions in Korea and energy-related policies should be carried out in addition. Additional tests on adaptation luminance greater than $3,000cd/m^2$ will be performed, through which application scope of the test findings will be broadened.

Image Processing-based Validation of Unrecognizable Numbers in Severely Distorted License Plate Images

  • Jang, Sangsik;Yoon, Inhye;Kim, Dongmin;Paik, Joonki
    • IEIE Transactions on Smart Processing and Computing
    • /
    • 제1권1호
    • /
    • pp.17-26
    • /
    • 2012
  • This paper presents an image processing-based validation method for unrecognizable numbers in severely distorted license plate images which have been degraded by various factors including low-resolution, low light-level, geometric distortion, and periodic noise. Existing vehicle license plate recognition (LPR) methods assume that most of the image degradation factors have been removed before performing the recognition of printed numbers and letters. If this is not the case, conventional LPR becomes impossible. The proposed method adopts a novel approach where a set of reference number images are intentionally degraded using the same factors estimated from the input image. After a series of image processing steps, including geometric transformation, super-resolution, and filtering, a comparison using cross-correlation between the intentionally degraded reference and the input images can provide a successful identification of the visually unrecognizable numbers. The proposed method makes it possible to validate numbers in a license plate image taken under low light-level conditions. In the experiment, using an extended set of test images that are unrecognizable to human vision, the proposed method provides a successful recognition rate of over 95%, whereas most existing LPR methods fail due to the severe distortion.

  • PDF

밝기 정보와 곡선전개 기반의 활성 모델 (Intensity Information and Curve Evolution Based Active Contour Model)

  • 김성곤
    • 정보처리학회논문지B
    • /
    • 제10B권5호
    • /
    • pp.521-526
    • /
    • 2003
  • 본 논문에서는 영역의 경계를 추출하기 위해 영상의 밝기 정보와 곡선전개 방식을 이용한 기하 활성 모델을 제안한다. 영역의 경계를 추출하는 문제를 추출한 영역의 평균 밝기 값과 전개중인 폐곡선 영역의 밝기 값의 차론 최소화시키는 것으로 설정한다. 최적의 해를 구하는 방법으로 레벨세트 이론을 적용한 곡선전개 방법을 이용한다. 이 방식은 일반적인 활성 모델에 비해 초기 곡선 설정에 제약이 없고 동시에 여러 영역의 경계 추출이 가능하다. 제안 모델은 에지 정보가 충분치 못한 영상의 경우에도 일반적인 에지 기반 방식에 비해 추출 결과가 양호하였다. 비등방성 확산 필터를 사용하여 영상을 전처리 함으로써 보다 나은 추출이 수행되었다. CT나 MRI 영상을 이용하여 모델의 성능을 확인하였다.

Methods for Adding Demand Response Capability to a Thermostatically Controlled Load with an Existing On-off Controller

  • Jin, Young Gyu;Yoon, Yong Tae
    • Journal of Electrical Engineering and Technology
    • /
    • 제10권3호
    • /
    • pp.755-765
    • /
    • 2015
  • A thermostatically controlled load (TCL) can be one of the most appropriate resources for demand response (DR) in a smart grid environment. DR capability can be effectively implemented in a TCL with various intelligent control methods. However, because traditional on-off control is still a commonly used method in a TCL, it is useful to develop a method for adding DR capability to the TCL with an existing on-off controller. As a specific realization of supervisory control for implementing DR capability in the TCL, two methods are proposed - a method involving the changing of a set point and a method involving the paralleling of an identified system without delay. The proposed methods are analyzed through the simulations with an electric heater for different power consumption levels in the on-state. Considerable cost benefit can be achieved with the proposed methods when compared with the case without DR. In addition, the observations suggest that a medium power consumption level, instead of the maximum power, in the on-state should be used for consistently obtaining the cost benefit without severe temperature deviation from the specified temperature range for DR.

How to improve oil consumption forecast using google trends from online big data?: the structured regularization methods for large vector autoregressive model

  • Choi, Ji-Eun;Shin, Dong Wan
    • Communications for Statistical Applications and Methods
    • /
    • 제29권1호
    • /
    • pp.41-51
    • /
    • 2022
  • We forecast the US oil consumption level taking advantage of google trends. The google trends are the search volumes of the specific search terms that people search on google. We focus on whether proper selection of google trend terms leads to an improvement in forecast performance for oil consumption. As the forecast models, we consider the least absolute shrinkage and selection operator (LASSO) regression and the structured regularization method for large vector autoregressive (VAR-L) model of Nicholson et al. (2017), which select automatically the google trend terms and the lags of the predictors. An out-of-sample forecast comparison reveals that reducing the high dimensional google trend data set to a low-dimensional data set by the LASSO and the VAR-L models produces better forecast performance for oil consumption compared to the frequently-used forecast models such as the autoregressive model, the autoregressive distributed lag model and the vector error correction model.

산초(山椒)의 이물허용치에 대한 각국의 약전 비교연구 (The Comparative Study on Zanthoxylum Peel's Impurity Tolerance Based on Pharmacopoeia by Countries)

  • 박수진;김인락
    • 대한본초학회지
    • /
    • 제25권1호
    • /
    • pp.45-54
    • /
    • 2010
  • Objectives : The purpose of this study is to determine the impurity tolerance of Zanthoxylum Peel. Methods : Compare with medicinal Herb Books and the Pharmacopoeia of 6 nations. Results : Current Pharmacopoeia show different Zanthoxylum Peel's Purity, such as 2.0% of seeds and fruit stalk, etc. in North Korea, 2% of seeds in Vietnam, totally 3% in China. On the other hand, Korea and Japan set the total number 26.0% including the specific numbers such as 20.0% of seeds, 5.0% of fruit stalk, 1.0% of the other foreign matter. This Zanthoxylum Peel's Purity, 26.0%, is too high compared to that of other medical matters specified by The Korean Pharmacopoeia Ninth Edition. When The Japanese Pharmacopoeia Sixth Edition firstly set the Zanthoxylum Peel's Purity, the herbal name was Fructus. However, since the part for medical usage in origin is well-ripen pericarp, not seed, the permissible level, 30.0%, is supposed to be simple error range, 3.0%. Conclusions : As a result, I think bills concerning the Zanthoxylum Peel's Purity should be revised to the total number 3.0% or specifically set the level 2.0% of seeds, 1.0% of fruit stalk, twig and so on.