• Title/Summary/Keyword: Variance/Mean Ratio

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Multistep Adaptive Smoothing Technique of Speckle Images (스펙클 영상의 다단계 적응 평활화 기법)

  • 김태균;남권문;박래홍
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.29B no.1
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    • pp.85-93
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    • 1992
  • In this paper, we propose a parameter-free smoothing method for speckle images, i.e., an adaptive least squares image smoothing technique implemented in a multistep environment. The pertinent smoothing window size at a given pixel is determined by the discontinuity measure which is defined by the ratio of the local variance and mean squares of intensity values of pixels over the smoothing window centered there. The mode of the discontinuity measure at each step is estimated to replace the noise variance parameter that is required in the adaptive smoothing. Computer simulation shows that the proposed multistep technique can smooth homogeneous regions satisfactorily while preserving fine details near boundaries.

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Estimation of Gauge R&R by Variance Components of Measurement ANOVA (측정 ANOVA의 분산성분에 의한 게이지 R&R 추정)

  • Choi, Sung-woon
    • Journal of the Korea Safety Management & Science
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    • v.12 no.1
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    • pp.199-205
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    • 2010
  • The research proposes the three-factor random measurement models for estimating the precision about operator, part, tool, and various measurement environments. The combined model with crossed and nested factors is developed to analyze the approximate F test by degrees of freedom given by Satterthwaite and point estimation of precisions from expected mean square. The model developed in this paper can be extended to the three useful models according to the type of nested designs. The study also provides the three-step procedures to evaluate the measurement precisions using three indexes such as SNR(Signal-To-Noise Ratio), R&R TR(Reproducibility&Repeatability-To-Total Precision Ratio), and PTR(Precision-To-Tolerance Ratio), The procedures include the identification of resolution, the improvement of R&R reduction, and the evaluation of precision effect.

Evaluation of Measurement Precisions Using Approximate F Tests and EMS in the Gauge R&R Studies (게이지 R&R 연구에서 근사 F검정과 EMS를 이용한 측정 정밀도의 평가)

  • Choi, Sung-Woon
    • Journal of the Korea Safety Management & Science
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    • v.11 no.3
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    • pp.209-216
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    • 2009
  • A development in method of evaluating the measurement precisions using approximate F tests and variance components from expected mean square (EMS) is investigated. The research proposes three-factor mixed measurement models with the fixed and random factors. Unrestricted and unconstrained design work was rarely studied, while restricted and constrained designs have been significantly discussed. The unrestricted and unconstrained designs assume to be an independence of interaction. The proposed evaluation method about the measurement precisions can be extended to four-factor random measurement model or mixed measurement model. The study also presents the three evaluation indexes of precisions such as R&RTR (Reproducibility & Repeatability-To-Total Precision Ratio), PTR (Precision-To-Tolerance Ratio), and SNR (Signal-To-Noise Ratio). Numerical examples are proposed to evaluate the approximate F tests with Satterthwaite degrees of freedom and three indexes using the measurement precisions from EMS.

Within- and Between-Individual Variation in Nutrient Intakes with Day of the Week and Season in Korean Adults (계절별, 요일별로 측정한 성인 남녀의 영양소 섭취량에서의 개인간 변이와 개인내 변이)

  • Kwon Eun Sil;Ahn YounJhin;Shim Jae Eun;Paik HeeYoung;Park Chan;Kimm Kuchan;Ju Young Su;Kim Dong Hyun
    • Journal of Nutrition and Health
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    • v.37 no.10
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    • pp.917-927
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    • 2004
  • This study was performed to examine component of variance in nutrient intakes and to estimate the level of accuracy with varying degree of precision in order to achieve estimates of usual nutrient intakes. Three-day dietary records including both weekdays and weekends were collected every 4 season over a I-year period from 36 males and 93 females aged 40 - 65 y. For each nutrient, we partitioned total intake variance into weekly (weekday vs weekend), seasonal, within- and between- individual variation as components of variance, using analysis of variance. It was found that major components of variance were within- and between-individual variation. Particularly, within-individual variation (57.2 - 87.1 %) was greater than between-individual variation (12.2 - 37.4%) for all nutrients. Weekly and seasonal variation contributed small components of variance for most nutrients. For protein, fat and carbohydrate, there were a little significant weekly variation (0.00 - 1.35%) in females but not in males. For some micronutrients, there were moderately significant seasonal variation (0.15 - 5.48%) in both sexes. Ratio of within- to between- individual variation ranged 1.4 (vitamin B$_2$) -4.5 (vitamin B$_1$) in males and 1.6 (carbohydrate) -2.9 (fat) in females. With total 12-day dietary records data, the maximum percentage deviation of observed intakes from usual (true) intakes ranged 12-37%. To estimate usual individual intakes within 20% of the true mean with 90% confidence level, 3 - 9 days of dietary survey were required for energy, protein, carbohydrate, phosphorus and iron, 13 - 19 days for fat and calcium, 25 - 29 days for vitamin A and vitamin C. Correlation coefficients between observed and true nutrient intakes were 0.71 - 0.91 for males, 0.81-0.91 for females. In conclusion, mean intakes of several nutrients can be reliably measured with the record method, using a limited number of days. Both nutrients of interest and the primary objectives should be taken account when planning method of assessment and number of replicates.

Detection Algorithm of Scanning worms using network traffic characteristics (네트워크 트래픽 특성을 이용한 스캐닝 웜 탐지기법)

  • Kim, Jae-Hyun;Kang, Shin-Hun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.17 no.1
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    • pp.57-66
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    • 2007
  • Scanning worms increase network traffic load because they randomly scan network addresses to find hosts that are susceptible to infection. Since propagation speed is faster than human reaction, scanning worms cause severe network congestion. So we need to build an early detection system which can automatically detect and quarantine such attacks. We propose algorithms to detect scanning worms using network traffic characteristics such as variance, variance to mean ratio(VMR) and correlation coefficient. The proposed algorithm have been verified by computer simulation. Compared to existing algorithm, the proposed algorithm not only reduced computational complexity but also improved detection accuracy.

Adult Image Detection Using an Intensity Filter and an Improved Hough Transform (명암 필터와 개선된 허프 변환을 이용한 성인영상 검출)

  • Jang, Seok-Woo;Kim, Sang-Hee;Kim, Gye-Young
    • Journal of the Korea Society of Computer and Information
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    • v.14 no.5
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    • pp.45-54
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    • 2009
  • In this paper, we propose an adult images detection algorithm using a mean intensity filter and an improved 2D Hough Transform. This paper is composed of three major steps including a training step, a recognition step, and a verification step. The training step generates a mean nipple variance filter that will be used for detecting nipple candidate regions in the recognition step. To make the mean variance filter, we converts an input color image into a gray scale image and normalize it, and make an average intensity filter for nipple areas. The recognition step first extracts edge images and finds connected components, and decides nipple candidate regions by considering the ratio of width and height of a connected component. It then decides final nipple candidates by calculating the similarity between the learned nipple average intensity filter and the nipple candidate areas. Also, it detects breast lines of an input image through the improved 2D Hough transform. The verification step detects breast areas and identifies adult images by considering the relations between nipple candidate regions and locations of breast lines.

Voice Activity Detection with Run-Ratio Parameter Derived from Runs Test Statistic

  • Oh, Kwang-Cheol
    • Speech Sciences
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    • v.10 no.1
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    • pp.95-105
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    • 2003
  • This paper describes a new parameter for voice activity detection which serves as a front-end part for automatic speech recognition systems. The new parameter called run-ratio is derived from the runs test statistic which is used in the statistical test for randomness of a given sequence. The run-ratio parameter has the property that the values of the parameter for the random sequence are about 1. To apply the run-ratio parameter into the voice activity detection method, it is assumed that the samples of an inputted audio signal should be converted to binary sequences of positive and negative values. Then, the silence region in the audio signal can be regarded as random sequences so that their values of the run-ratio would be about 1. The run-ratio for the voiced region has far lower values than 1 and for fricative sounds higher values than 1. Therefore, the parameter can discriminate speech signals from the background sounds by using the newly derived run-ratio parameter. The proposed voice activity detector outperformed the conventional energy-based detector in the sense of error mean and variance, small deviation from true speech boundaries, and low chance of missing real utterances

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Effects of Rain Water Sampler on the Results of Analysis (雨水採取機가 雨水成分에 미치는 影響)

  • 李敏熙;韓義正;辛燦基;韓振錫
    • Journal of Korean Society for Atmospheric Environment
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    • v.3 no.2
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    • pp.53-61
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    • 1987
  • Automatic and manual rain smaplers wre installed at the roof of National Institute of Environmental Research (NIER), and the rain sampling and measurement were conducted during the period April to August 31, 1987. The rain sampling and measurement were carried out in the following manners: The 1st : Acidity and conductivity were measured entirely by automatic rain sampler (continuous measurement) The 2nd : Acidity and conductivity wrer measured in the laboratory with the sample that was taken out of automatic rain sampler. The 3rd : Acidity and conductivity were measured in the laboratory with the sample that was taken out of manual rain sampler. Afterwards, those different measurement values were compared each other and the following conclusions were obtained: 1) The pH of the continous measurement by the automatic sampler was lower than that of the laboratory measurement, and it was reversed in case of the conductivity. 2) The significance was recognized at 5% risk ratio for the population mean of difference of the measurement values of the pH and conductivity from both samples. 3) The significance was not recognized at 5% risk ratio by the analysis of variance by one way layout for the pH and conductivity. 4) The significance was recognized at 5% risk ratio by the analysis of variance by two way layouts for the pH conductivity. 5) The significance was recognized at 5% rrisk ratio for the differences of the pH values obtained by oboth samplers, and no significance was recognized for conductivity. 6) In comparison of the measurement values from the two samplers were shown a good correlation for pH; correlation coefficient (r) = 0.63, and regression equation Y = 0.53X + 2.78. For conductivity, the correlation was also excellent; correlation coefficient (r) = 0.53 and regression equation Y = 0.63X + 5.65.

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Spatial Distribution and Sampling Plan for Pink Citrus Rust Mite, Aculops pelekassi (Acari: Eriophyidae) in Citrus Orchard (감귤원에서 귤녹응애 공간분포 분석과 표본조사법 개발)

  • Song, Jeong-Heub;Hong, Soon-Yeong;Lee, Shin-Chan
    • Korean journal of applied entomology
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    • v.51 no.2
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    • pp.91-97
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    • 2012
  • The dispersion indices, spatial pattern and sampling plan for pink citrus rust mite (PCRM), Aculops pelekassi, monitoring was investigated. Dispersion indices of PCRM indicated the aggregated spatial pattern. Taylor's power law provided better description of variance-mean relationship than Iwao's patchiness regression. Fixed-precision levels (D) of a sequential sampling plan were developed using by Taylor's power law parameters generated from PCRM on fruit sample (cumulated number of PCRM in $cm^2$ of fruit). Based on Kono-Sugino's empirical binomial the mean density per $cm^2$ could be estimated from fruit ratio with more than 12 rust mites per $cm^2$: $ln(m)=4.61+1.23ln[-ln(1-p_{12})]$. To determine the optimal tally threshold, the variance (var(lnm)) for mean (lnm) in Kono-Sugino equation was estimated. The lower and narrow ranged change of variance for esimated mean showed at a tally threshold of 12. To estimate PCRM mean density per $cm^2$ at fixed precision level 0.25, the required sample number was 13 trees, 5 fruits per tree and 2 points per fruit (total 130 samples).

The Optimization of the Production Ratio by the Mean-variance Analysis of the Chemical Products Prices (화학 제품 가격의 변동으로 인한 위험을 최소화하며 수익을 극대화하기 위한 생산 비율 최적화에 관한 연구)

  • Park, Jeong-Ho;Park, Sun-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.12
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    • pp.1169-1172
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    • 2006
  • The prices of chemical products are fluctuated by several factors. The chemical companies can't predict and be ready to all of these changes, so they are exposed to the risk of a profit fluctuation. But they can reduce this risk by making a well-diversified product portfolio. This problem can be thought as the optimization of the product portfolio. We assume that the profits come from the 'spread' between a naphtha and a chemical product. We calculate a mean and a variation of each spread and develop an automatic module to calculate the optimal portion of each product. The theory is based on the Markowitz portfolio management. It maximizes the expected return while minimizing the volatility. At last we draw an investment selection curve to compare each alternative and to demonstrate the superiority. And we suggest that an investment selection curve can be a decision-making tool.