• Title/Summary/Keyword: change matrix

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Multivariate control charts based on regression-adjusted variables for covariance matrix

  • Kwon, Bumjun;Cho, Gyo-Young
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.4
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    • pp.937-945
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    • 2017
  • The purpose of using a control chart is to detect any change that occurs in the process. When control charts are used to monitor processes, we want to identify this changes as quickly as possible. Many problems in quality control involve a vector of observations of several characteristics rather than a single characteristic. Multivariate CUSUM or EWMA charts have been developed to address the problem of monitoring covariance matrix or the joint monitoring of mean vector and covariance matrix. However, control charts tend to work poorly when we use the highly correlatted variables. In order to overcome it, Hawkins (1991) proposed the use of regression adjustment variables. In this paper, to monitor covariance matrix, we investigate the performance of MEWMA-type control charts with and without the use of regression adjusted variables.

Land-use Change Assessment by Permanent Sample Plots in National Forest Inventory (국가산림자원조사 고정표본점 자료를 이용한 토지이용변화 평가)

  • Yim, Jong-Su;Kim, Rae Hyun;Lee, Sun Jeoung;Son, Yeong Mo
    • Journal of Climate Change Research
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    • v.6 no.1
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    • pp.33-40
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    • 2015
  • Forests are to be recognized as an important carbon sink under the UNFCCC that consist of above- and below-biomass, dead organic matter (DOM) such as dead wood and litter, and soil organic matter (SOM). In order to asses for DOM and SOM, however, it is relevant to land-use change matrices over last 20 years for each land-use category. In this study, a land-use change matrix was produced and its uncertainty was assessed using a point sampling technique with permanent sample plots in national forest inventory at Chungbuk province. With point sampling estimated areas at 2012 year for each land-use category were significantly similar to the true areas by given six land-use categories. Relative standard error in terms of uncertainty of land-use change among land-use categories ranged in 4.3~44.4%, excluding the other land. Forest and cropland covered relatively large areas showed lower uncertainty compared to the other land-use categories. This result showed that selected permanent samples in the NFI are able to support for producing land-use change matrix at a national or province level. If the $6^{th}$ NFI data are fully collected, the uncertainty of estimated area should be improved.

Fine Needle Aspiration Cytology of Matrix Producing Carcinoma of the Breast - A Case Report - (유방의 기질형성 암종의 세침흡인 세포학적 소견 - 1예 보고 -)

  • Kim, Hyun-Jung;Park, A-Young;Kim, Dong-Won;Lee, Dong-Wha;Kwon, Kui-Hyang
    • The Korean Journal of Cytopathology
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    • v.8 no.2
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    • pp.174-178
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    • 1997
  • Matrix producing carcinoma of the breast is a variant of heterologous metaplastic carcinoma which is defined as "overt carcinoma with direct transition to a cartilaoenous and/or osseous stromal matrix without an intervening spindle cell zone or osteoclastic cells". This tumor is very rare, occuring in less than 0.2% of total breast carcinoma, but the prognosis is better than other metaplastic carcinoma. We experienced a case of fine needle aspiration(FNA) cytologic finding of matrix producing carcinoma of the breast. A 75-year old woman, who presented a right huge breast mass$(9{\times}8cm)$ during 10months, was examined. Mammography reveals right lateral mass with even density without calcification. Breast ultrasonography shows multifocal hypoechogenic cystic change in the huge mass, suggesting resolving hematoma or carcinoma or sarcoma with necrosis. On cytologic finding of FNA, myxoid matrix was the dominant feature and the rest of the material was composed of scanty isolated atypical cells with large irregular nuclei. The histologic finding was moderately differentiated adenocarcinoma with abundant cartilagenous matrix and focal squamous metaplasia.

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Wear Properties of Epoxy Matrix Nanocomposites (에폭시 기지 나노복합재료의 마모 특성)

  • Kim, J.D.;Kim, H.J.;Koh, S.W.;Kim, Y.S.
    • Journal of Power System Engineering
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    • v.14 no.6
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    • pp.83-88
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    • 2010
  • The wear behavior of epoxy matrix composites filled with nano sized silica particles is discussed in this paper. Especially, the variation of the coefficient of friction and the wear resistance according to the change of apply load and sliding velocity were investigated for these materials. Wear tests of pin-on-disc mode were carried out and the wear test results exhibited as following ; The epoxy matrix composites showed lower coefficient of friction compared to the neat epoxy through the whole sliding distance. As increasing the sliding velocity the epoxy matrix composites indicated lower coefficient of friction, whereas the neat epoxy showed higher coefficient of friction as increasing the sliding velocity. The specific friction work of both materials were increased with apply load. In case of the epoxy matrix composites, the running in periods of friction were reduced as increase in apply load. The epoxy matrix composites were improved the wear resistance by adding the nano silica particles remarkably. It is expected that the load carrying capacity of the epoxy matrix composites will be improved by increase of Pv factor.

Comparison of Activity Capacity Change and GFR Value Change According to Matrix Size during 99mTc-DTPA Renal Dynamic Scan (99mTc-DTPA 신장 동적 검사(Renal Dynamic Scan) 시 동위원소 용량 변화와 Matrix Size 변경에 따른 사구체 여과율(Glomerular Filtration Rate, GFR) 수치 변화 비교)

  • Kim, Hyeon;Do, Yong-Ho;Kim, Jae-Il;Choi, Hyeon-Jun;Woo, Jae-Ryong;Bak, Chan-Rok;Ha, Tae-Hwan
    • The Korean Journal of Nuclear Medicine Technology
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    • v.24 no.1
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    • pp.27-32
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    • 2020
  • Purpose Glomerular Filtration Rate(GFR) is an important indicator for evaluating renal function and monitoring the progress of renal disease. Currently, the method of measuring GFR in clinical trials by using serum creatinine value and 99mTc-DTPA(diethylenetriamine pentaacetic acid) renal dynamic scan is still useful. After the Gates method of formula was announced, when 99mTc-DTPA Renal dynamic scan is taken, it is applied the GFR is measured using a gamma camera. The purpose of this paper is to measure the GFR by applying the Gates method of formula. It is according to effect activity and matrix size that is related in the GFR. Materials and Methods Data from 5 adult patients (patient age = 62 ± 5, 3 males, 2 females) who had been examined 99mTc-DTPA Renal dynamic scan were analyzed. A dynamic image was obtained for 21 minutes after instantaneous injection of 99mTc-DTPA 15 mCi into the patient's vein. To evaluate the glomerular filtration rate according to changes in activity and matrix size, total counts were measured after setting regions of interest in both kidneys and tissues in 2-3 minutes. The distance from detector to the table was maintained at 30cm, and the capacity of the pre-syringe (PR) was set to 15, 20, 25, 30 mCi, and each the capacity of post-syringe (PO) was 1, 5, 10, 15 mCi is set to evaluate the activity change. And then, each matrix size was changed to 32 × 32, 64 × 64, 128 × 128, 256 × 256, 512 × 512, and 1024 × 1024 to compare and to evaluate the values. Results As the activity increased in matrix size, the difference in GFR gradually decreased from 52.95% at the maximum to 16.67% at the minimum. The GFR value according to the change of matrix size was similar to 2.4%, 0.2%, 0.2% of difference when changing from 128 to 256, 256 to 512, and 512 to 1024, but 54.3% of difference when changing from 32 to 64 and 39.43% of difference when changing from 64 to 128. Finally, based on the presently used protocol, 256 × 256, PR 15 mCi and PO 1 mCi, the GFR value was the largest difference with 82% in PR 15 mCi and PO 1 mCi. conditions, and at the least difference is 0.2% in the conditions of PR 30 mCi and PO 15 mCi. Conclusion Through this paper, it was confirmed that when measuring the GFR using the gate method in the 99mTc-DTPA renal dynamic scan. The GFR was affected by activity and matrix size changes. Therefore, it is considered that when taking the 99mTc-DTPA renal dynamic scan, is should be careful by applying appropriate parameters when calculating GFR in the every hospital.

Development and Evaluation of a Texture-Based Urban Change Detection Method Using Very High Resolution SAR Imagery (고해상도 SAR 영상을 활용한 텍스처 기반의 도심지 변화탐지 기법 개발 및 평가)

  • Kang, Ah-Reum;Byun, Young-Gi;Chae, Tae-Byeong
    • Korean Journal of Remote Sensing
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    • v.31 no.3
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    • pp.255-265
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    • 2015
  • Very high resolution (VHR) satellite imagery provide valuable information on urban change monitoring due to multi-temporal observation over large areas. Recently, there has been increased interest in the urban change detection technique using VHR Synthetic Aperture Radar (SAR) imaging system, because it can take images regardless of solar illumination and weather condition. In this paper, we proposed a texture-based urban change detection method using the VHR SAR texture features generated from Gray-Level Co-Occurrence Matrix (GLCM). In order to evaluate the efficiency of the proposed method, the result was compared, visually and quantitatively, with the result of Non-Coherent Change Detection (NCCD) which is widely used for the change detection of VHR SAR image. The experimental results showed the greater detection accuracy and the visually satisfactory result compared with the NCCD method. In conclusion, the proposed method has shown a great potential for the extraction of urban change information from VHR SAR imagery.

Studies on the Evolution of the Surface Roughness with Development of Surface Compound Layer in Salt Bath Nitrocarburising (Tufftride) (침질침탄시 화합물층의 성장에 따른 표면조도 변화에 관한 연구)

  • Song, K.S.;Moon, K.I.;Kim, S.W.
    • Journal of the Korean Society for Heat Treatment
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    • v.16 no.5
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    • pp.253-259
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    • 2003
  • In this study, to find out the reason of deterioration in surface roughness of steel and cast iron after Tufftride, it has been investigated on the relation between the surface roughness and various factors such as the evolution of compound layer, surface morphology, and surface hardness, and change of pore ratio in the compound layer during Tufftride at $580^{\circ}C$. It is found that the surface roughness was increased with the evolution of compound layer during Tufftride of steel and cast iron. The change of surface roughness after Tufftride was reduced with decreasing tho content of carbon and cementite ($Fe_3C$) in the materials. in the cast irons, the various shaped graphites that was exposed to the surface should induce the discontinuous growth of the compound layer, and this resulted in the incoherent interfaces between matrix and compound layer and the deterioration of surface roughness. In the steels, the existence of cementites in the matrix resulted in the incoherent interfaces between matrix and compound layer. It is considered that during Tufftride the surface roughness must be mainly influenced by the formation of the incoherent interface between compound layer and matrix that is affected by some factors such as the microstructure, the composition, and the hardness of the matrix.

SCANNING ELECTRON MICROSCOPY ANALYSIS OF FUEL/MATRIX INTERACTION LAYERS IN HIGHLY-IRRADIATED U-Mo DISPERSION FUEL PLATES WITH Al AND Al-Si ALLOY MATRICES

  • Keiser, Dennis D. Jr.;Jue, Jan-Fong;Miller, Brandon D.;Gan, Jian;Robinson, Adam B.;Medvedev, Pavel;Madden, James;Wachs, Dan;Meyer, Mitch
    • Nuclear Engineering and Technology
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    • v.46 no.2
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    • pp.147-158
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    • 2014
  • In order to investigate how the microstructure of fuel/matrix-interaction (FMI) layers change during irradiation, different U-7Mo dispersion fuel plates have been irradiated to high fission density and then characterized using scanning electron microscopy (SEM). Specifially, samples from irradiated U-7Mo dispersion fuel elements with pure Al, Al-2Si and AA4043 (~4.5 wt.%Si) matrices were SEM characterized using polished samples and samples that were prepared with a focused ion beam (FIB). Features not observable for the polished samples could be captured in SEM images taken of the FIB samples. For the Al matrix sample, a relatively large FMI layer develops, with enrichment of Xe at the FMI layer/Al matrix interface and evidence of debonding. Overall, a significant penetration of Si from the FMI layer into the U-7Mo fuel was observed for samples with Si in the Al matrix, which resulted in a change of the size (larger) and shape (round) of the fission gas bubbles. Additionally, solid fission product phases were observed to nucleate and grow within these bubbles. These changes in the localized regions of the microstructure of the U-7Mo may contribute to changes observed in the macroscopic swelling of fuel plates with Al-Si matrices.

The effects of matrix aging and residual stress changes on $Avimid^{(R)}$ K3B/IM7 laminates (수지 노화와 잔류응력 변화가 $Avimid^{(R)}$ K3B/IM7 복합재 적층에 미치는 영향)

  • Kim, Hyung-Won
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.3 s.22
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    • pp.124-130
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    • 2005
  • In this paper, the effects of matrix hygrothermal aging and residual stress changes on $Avimid^{(R)}$ K3B/IM7 laminates in $80^{\circ}C$ water were studied. The factors causing the $80^{\circ}C$ water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses. After 500 hours fully saturated aging of the neat resin, the weight gain was 1.55% increase with the diffusion coefficient $7{\times}10^{-6}m^2/s$ and the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the $[+45/0/-45/90]_s$ K3B/IM7 laminates in $80^{\circ}C$ water, the weight gain was 0.41% increase with the diffusion coefficient $1{\times}10^{-6}m^2/s$ and the loss of the microcracking fracture toughness was 43.8% of the original toughness. To see whether the residual stress influenced the fracture toughness, two ply $[90^{\circ}/0^{\circ}]$ laminates were put in $80^{\circ}C$ water from 2 hours to 8 hours. The changes in residual stress in 8 hours are less than 3MPa. Because the 3MPa change is not sufficient to degrade the laminates, the main factor to degrade the microcracking fracture toughness was the degradation of the matrix fracture toughness.

Vibration analysis of asymmetric shear wall and thin walled open section structures using transfer matrix method

  • Bozdogan, Kanat Burak;Ozturk, Duygu
    • Structural Engineering and Mechanics
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    • v.33 no.1
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    • pp.95-107
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    • 2009
  • A method for vibration analysis of asymmetric shear wall and Thin walled open section structures is presented in this paper. The whole structure is idealized as an equivalent bending-warping torsion beam in this method. The governing differential equations of equivalent bending-warping torsion beam are formulated using continuum approach and posed in the form of simple storey transfer matrix. By using the storey transfer matrices and point transfer matrices which consider the inertial forces, system transfer matrix is obtained. Natural frequencies can be calculated by applying the boundary conditions. The structural properties of building may change in the proposed method. A numerical example has been solved at the end of study by a program written in MATLAB to verify the presented method. The results of this example display the agreement between the proposed method and the other valid method given in literature.