• 제목/요약/키워드: MAR.

검색결과 1,058건 처리시간 0.029초

Iterative Metallic Artifact Reduction 알고리즘 적용 CT 재구성영상의 CT Number 변화율 분석 (The Analysis of CT Number Rate of Change of Applying The Iterative Metallic Artifact Reduction Algorithm for CT Reconstruction Image)

  • 김현주;윤준
    • 한국산학기술학회논문지
    • /
    • 제18권7호
    • /
    • pp.84-91
    • /
    • 2017
  • 본 연구는 컴퓨터 단층촬영 영상에서 제거할 수 없는 의료용 고밀도 물질을 Somatom Definition Flash(Siemens, Enlarge, Germany.)와 GE 64-MDCT (Discovery 750 HD, GE HEALTHCARE, Milwaukee, USA.)스캔 후 획득한 팬텀영상 데이터와 이미 촬영된 Raw 데이터영상을 이용하여 IMAR 알고리즘과 MAR 알고리즘 적용 및 재구성한 후 CT 재구성영상의 CT Number 변화율을 정량적으로 분석하였다. 그 결과 팬텀영상의 모든 의료용 고밀도 물질은 IMAR 알고리즘과 MAR 알고리즘 적용 시 CT Number의 변화와 영상의 차이가 있는 것으로 나타났지만(p<0.05). Stainless Steel 재질은 Black streak artifact에서 MAR 또는 IMAR 알고리즘 적용 시 재구성 영상의 변화와 CT Number의 변화차이가 없는 것으로 분석되었다(p>0.05). 또한 이미 촬영된 Raw 데이터영상 분석결과 IMAR 알고리즘 적용 시 적용 전에 비하여 영상 CT Number 변화가 있어, IMAR 알고리즘 적용은 Attenuation deviation에 영향을 미치는 것을 알 수 있었다. 이 결과를 바탕으로 향후 Implant시술 후 추적 CT검사 시 수술부위 및 주변조직의 상태를 관찰하는데 유용할 것으로 사료된다.

최대 무채색 영역을 이용한 광원의 분광분포 추정 (Estimation of Spectral Distribution of Illumination Using Maximum Achromatic Region)

  • 김희수;김윤태;이철희;하영호
    • 대한전자공학회논문지SP
    • /
    • 제38권4호
    • /
    • pp.392-400
    • /
    • 2001
  • 본 논문에서는 단일 영상에 포함된 광원의 분광분포를 추정하는 광원추정 알고리즘을 제안한다. 제안된 광원 추정 방법은 두 단계로 이루어져 있다. 첫째, 변형된 회색계 가정(modified gray world assumption)을 이용하여 부분적으로 광원의 영향을 배제한 후 밝으면서도 무채색에 가까운 최대 무채색 영역을 찾아 그 영역의 표면 분광 반사율을 구한다. 이때 최대 무채색 영역의 표면 분광 반사율은 1269개의 Munsell 색 표본에 대하여 주성분 분석 방법을 이용하여 추정하였다. 둘째, 주어진 Munsell 색 표본과 대표 광원의 조합으로 반사광의 모집단을 만들었다. 다음 최대 무채색 영역의 각 화소와 반사광 모집단과의 색차를 비교하여 최대 무채색 영역과 색차가 가장 적은 반사광 표본을 선택하고 이를 최대 무채색 영역에 대한 반사광의 분광분포로 정의한다. 최종적으로 최저 무채색 영역의 반사광 분광분포를 해당하는 표면 분광반사율로 나누어줌으로써 영상에 포함된 광원의 분광분포를 추정한다. 제안한 알고리듬의 성능을 평가하기 위하여 유색 광원에 조명된 영상에 대한 광원 추정 실험을 하였으며 기존의 방법과 추정된 광원의 분광 분포 비교 및 색차 비교를 통해 그 타당성을 검증하였다.

  • PDF

도서(섬)지역 노인의 우울정도에 따른 식행동단계와 영양소 섭취상태 조사 (A Survey on Stages of Dietary Behavior Change and Nutrient Intake Status of Old People in Islands Areas According to Depression Degree)

  • 박필숙;박경옥;정구범;천병렬;최미화;박미연
    • 한국생활과학회지
    • /
    • 제18권6호
    • /
    • pp.1349-1361
    • /
    • 2009
  • The present study was designed to analyze the relationship of dietary behavior change and nutrient intake status owing to a depression degree for 143 people over 65 years old living in Echeong and Hansan islands area, South Korea. The depression degree was classified into non depression, minor depression and depressive disorder groups using. The Center for Epidemiological Studies-Depression (CES-D) scale for 143 subjects. The results are as follows; the depression degree significantly made differences according to sex (p<.001), marital status (p<.05), self-related economic status (p<.001) and living expenses (p<.05). The stage of dietary behavior according to the depression degree was as follows; the non depression group was 57.6%, the minor group was 46.8% and the depressive disorder group was 27.1% of the subjects. The intake frequency of the cereal group (p<.05) and fruit group (p<.01) was significantly different among food group intake status owing to the depression degree. Mean adequacy ratio(MAR)[13], MAR[10], and MAR[4] of the depressive disorder group were significantly lower than that of the non depression and minor depression groups. Each average of MAR[13], MAR[10], and MAR[4] for the subjects were $0.68{\pm}0.2$, $0.67{\pm}0.2$, and $0.55{\pm}0.2$. Concerned about the nutrients over 1.0 index of nutritional quality(INQ) 8 nutrients of protein, Phosphorous, iron, zinc, vitamin A, vitamin $B_6$, niacin and vitamin C belonged to the non depression group. Additionally, 6 nutrients of protein, Phosphorous, iron, zinc, vitamin $B_6$ and niacin were included for minor depression and depressive disorder groups.

농촌 장수마을 여자 노인의 식행동 변화단계 모형에 따른 식품 및 영양소 섭취상태 비교 (A Comparison of Food and Nutrient Intake Status of Aged Females in A Rural Long Life Community by the Stage Model of Dietary Behavior Change)

  • 박미연;천병렬;조순재;정구범;허철회;김금란;박필숙
    • 대한지역사회영양학회지
    • /
    • 제13권1호
    • /
    • pp.34-45
    • /
    • 2008
  • For the correct dietary habit and balanced dietary intake of aged people, the nutrition management that fits to the dietary behavior change stage has to be accomplished. In order to do so, in this paper, we chose 175 women that are aged more than 65 years old who are rural long life community residents and surveyed the dietary intake for 2 days including a twice depth interview and the 24 hour recall method. Also, for the sake of our aim, using the transtheoretical model, the dietary behavior change stage group was divided into the contemplation stage group, the preparation stage group, the action stage group and the maintenance stage group. The results are as follows: In the intake amount of protein (p < 0.01), vitamin $B_1$ (p < 0.05) and vitamin $B_6$ (p < 0.05), the intake amount of these nutrients in the action stage group and the maintenance stage group were significantly larger than the intake amount in the contemplation stage group and the preparation stage group. The nutrition evaluation according to the dietary behavior change stage, the ratio of subjects who took insufficient amount of energy, protein, vitamin A, and vitamin C were low as the dietary behavior change stage was upgraded. The subjects of maintenance stage group were most likely to consume vegetables more than once a day, and consume fruits and milk and milk products more than 5 times/week. MAR [13], MAR [10] and MAR [4] of subjects in the action stage group and the maintenance stage group were significantly higher than MAR [13], MAR [10] and MAR [4] of subjects in the contemplation stage group and the preparation stage group (p < 0.001). From the above results, there were differences of nutrient intakes according to the dietary behavior change stage. Therefore, it is considered that the intervention for the dietary behavior motivation induction has to be advanced before accomplishing the individually fitting intervention at the time of nutrient management intervention.

2월과 3월의 난류분포에 대한 연구 (The study of the turbulence distribution of Feb. and Mar.)

  • 신대원
    • 한국항공운항학회지
    • /
    • 제13권2호
    • /
    • pp.27-34
    • /
    • 2005
  • This study is performed to analyze the turbulence distribution of Fev. & Mar. in 2000 by the analysis of the parameters related with flight data of FDR(Flight Data Recorder). In the analysis, we selected the Solid State Flight Data Recorder(SSFDR) & Universal Flight Data Recorder(UFDR) flight data of the exact same aircraft(capacity 120 persons). Through this study, we verified that turbulence is concerned with configuration of the ground and flight situation of aircraft.

  • PDF

STATIONARITY AND β-MIXING PROPERTY OF A MIXTURE AR-ARCH MODELS

  • Lee, Oe-Sook
    • 대한수학회보
    • /
    • 제43권4호
    • /
    • pp.813-820
    • /
    • 2006
  • We consider a MAR model with ARCH type conditional heteroscedasticity. MAR-ARCH model can be derived as a smoothed version of the double threshold AR-ARCH model by adding a random error to the threshold parameters. Easy to check sufficient conditions for strict stationarity, ${\beta}-mixing$ property and existence of moments of the model are given via Markovian representation technique.

LAGUERRE EXPANSIONS AND PRODUCTS OF DISTRIBUTIONS

  • Catuogno, Pedro;Martinez, Federico;Molina, Sandra
    • 대한수학회논문집
    • /
    • 제23권2호
    • /
    • pp.201-209
    • /
    • 2008
  • In this paper we introduce two products of tempered distributions with positive support. These products are based in the Laguerre representation of distributions. We calculate some products as, $[{\delta}]x^{\lambda}_+={\delta}[x^{\lambda}_+]=0\;and\;[x^{\lambda}_+]x^{\mu}_+=x^{{\lambda}+{\mu}}_+$ for appropriate ${\lambda}$ and ${\mu}$.

Ni기 초내열합금의 일방향 응고에서 탄화물의 Trapping과 성장 거동 (A Study of Carbide Thapping and Growth in the Directional Solidification of MAR-M247 LC Super alloy)

  • 이재현;진건;이용태;최승주
    • 연구논문집
    • /
    • 통권26호
    • /
    • pp.95-102
    • /
    • 1996
  • The carbide growth behavior of MAR-M247 LC alloy was investigated by directional solidification and quench method. The carbide volume fraction, trapping and growth behavior were correlated with the growth rate. It was found that the carbide volume fraction decreases at slower growth rate. This decreasing was caused by lower solid-liquid interface trapping ability at the slower growth rate.

  • PDF