• Title, Summary, Keyword: Quantitative fluctuation

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The Influence of Iteration and Subset on True X Method in F-18-FPCIT Brain Imaging (F-18-FPCIP 뇌 영상에서 True-X 재구성 기법을 기반으로 했을 때의 Iteration과 Subset의 영향)

  • Choi, Jae-Min;Kim, Kyung-Sik;NamGung, Chang-Kyeong;Nam, Ki-Pyo;Im, Ki-Cheon
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.1
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    • pp.122-126
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    • 2010
  • Purpose: F-18-FPCIT that shows strong familiarity with DAT located at a neural terminal site offers diagnostic information about DAT density state in the region of the striatum especially Parkinson's disease. In this study, we altered the iteration and subset and measured SUV${\pm}$SD and Contrasts from phantom images which set up to specific iteration and subset. So, we are going to suggest the appropriate range of the iteration and subset. Materials and Methods: This study has been performed with 10 normal volunteers who don't have any history of Parkinson's disease or cerebral disease and Flangeless Esser PET Phantom from Data Spectrum Corporation. $5.3{\pm}0.2$ mCi of F-18-FPCIT was injected to the normal group and PET Phantom was assembled by ACR PET Phantom Instructions and it's actual ratio between hot spheres and background was 2.35 to 1. Brain and Phantom images were acquired after 3 hours from the time of the injection and images were acquired for ten minutes. Basically, SIEMENS Bio graph 40 True-point was used and True-X method was applied for image reconstruction method. The iteration and Subset were set to 2 iterations, 8 subsets, 3 iterations, 16 subsets, 6 iterations, 16 subsets, 8 iterations, 16 subsets and 8 iterations, 21 subsets respectively. To measure SUVs on the brain images, ROIs were drawn on the right Putamen. Also, Coefficient of variance (CV) was calculated to indicate the uniformity at each iteration and subset combinations. On the phantom study, we measured the actual ratio between hot spheres and back ground at each combinations. Same size's ROIs were drawn on the same slide and location. Results: Mean SUVs were 10.60, 12.83, 13.87, 13.98 and 13.5 at each combination. The range of fluctuation by sets were 22.36%, 10.34%, 1.1%, and 4.8% respectively. The range of fluctuation of mean SUV was lowest between 6 iterations 16 subsets and 8 iterations 16 subsets. CV showed 9.07%, 11.46%, 13.56%, 14.91% and 19.47% respectively. This means that the numerical value of the iteration and subset gets higher the image's uniformity gets worse. The range of fluctuation of CV by sets were 2.39, 2.1, 1.35, and 4.56. The range of fluctuation of uniformity was lowest between 6 iterations, 16 subsets and 8 iterations, 16 subsets. In the contrast test, it showed 1.92:1, 2.12:1, 2.10:1, 2.13:1 and 2.11:1 at each iteration and subset combinations. A Setting of 8 iterations and 16 subsets reappeared most close ratio between hot spheres and background. Conclusion: Findings on this study, SUVs and uniformity might be calculated differently caused by variable reconstruction parameters like filter or FWHM. Mean SUV and uniformity showed the lowest range of fluctuation at 6 iterations 16 subsets and 8 iterations 16 subsets. Also, 8 iterations 16 subsets showed the nearest hot sphere to background ratio compared with others. But it can not be concluded that only 6 iterations 16 subsets and 8 iterations 16 subsets can make right images for the clinical diagnosis. There might be more factors that can make better images. For more exact clinical diagnosis through the quantitative analysis of DAT density in the region of striatum we need to secure healthy people's quantitative values.

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Simultaneous Unwrapping Phase and Error Recovery from Inhomogeneity (SUPER) for Quantitative Susceptibility Mapping of the Human Brain

  • Yang, Young-Joong;Yoon, Jong-Hyun;Baek, Hyun-Man;Ahn, Chang-Beom
    • Investigative Magnetic Resonance Imaging
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    • v.22 no.1
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    • pp.37-49
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    • 2018
  • Purpose: The effect of global inhomogeneity on quantitative susceptibility mapping (QSM) was investigated. A technique referred to as Simultaneous Unwrapping Phase with Error Recovery from inhomogeneity (SUPER) is suggested as a preprocessing to QSM to remove global field inhomogeneity-induced phase by polynomial fitting. Materials and Methods: The effect of global inhomogeneity on QSM was investigated by numerical simulations. Three types of global inhomogeneity were added to the tissue susceptibility phase, and the root mean square error (RMSE) in the susceptibility map was evaluated. In-vivo QSM imaging with volunteers was carried out for 3.0T and 7.0T MRI systems to demonstrate the efficacy of the proposed method. Results: The SUPER technique removed harmonic and non-harmonic global phases. Previously only the harmonic phase was removed by the background phase removal method. The global phase contained a non-harmonic phase due to various experimental and physiological causes, which degraded a susceptibility map. The RMSE in the susceptibility map increased under the influence of global inhomogeneity; while the error was consistent, irrespective of the global inhomogeneity, if the inhomogeneity was corrected by the SUPER technique. In-vivo QSM imaging with volunteers at 3.0T and 7.0T MRI systems showed better definition in small vascular structures and reduced fluctuation and non-uniformity in the frontal lobes, where field inhomogeneity was more severe. Conclusion: Correcting global inhomogeneity using the SUPER technique is an effective way to obtain an accurate susceptibility map on QSM method. Since the susceptibility variations are small quantities in the brain tissue, correction of the inhomogeneity is an essential element for obtaining an accurate QSM.

Independent Component Analysis of Mixels in Agricultural Land Using An Airborne Hyperspectral Sensor Image

  • Kosaka, Naoko;Shimozato, Masao;Uto, Kuniaki;Kosugi, Yukio
    • Proceedings of the KSRS Conference
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    • pp.334-336
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    • 2003
  • Satellite and airborne hyperspectral sensor images are suitable for investigating the vegetation state in agricultural land. However, image data obtained by an optical sensor inevitably includes mixels caused by high altitude observation. Therefore, mixel analysis method, which estimates both the pure spectra and the coverage of endmembers simultaneously, is required in order to distinguish the qualitative spectral changes due to the chlorophyll quantity or crop variety, from the quantitative coverage change. In this paper, we apply our agricultural independent component analysis (ICA) model to an airborne hyperspectral sensor image, which includes noise and fluctuation of coverage, and estimate pure spectra and the mixture ratio of crop and soil in agricultural land simultaneously.

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Large Eddy Simulation of Shock-Boundary Layer Interaction

  • Teramoto, Susumu
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.426-432
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    • 2004
  • Large-Eddy Simulation (LES) is applied for the simulation of compressible flat plate boundary with Reynolds number up to 5 X 10$^{5}$ . Numerical examples include shock/boundary layer interaction and boundary layer transition, aiming future application to the analysis of transonic fan/compressor cascades. The present LES code uses hybrid com-pact/WENO scheme for the spatial discretization and compact diagonalized implicit scheme for the time integration. The present code successfully predicted the bypass transition of subsonic boundary layer. As for supersonic turbulent boundary layer, mean and fluctuation velocity of the attached boundary, as well as the evolution of the friction coefficient and the displacement thickness both upstream and downstream of the separation region are all in good agreement with experiment. The separation point also agreed with the experiment. In the simulation of the shock/laminar boundary layer interaction, the dependence of the transition upon the shock strength is reproduced qualitatively, but the extent of the separation region is overpredicted. These numerical examples show that LES can predict the behavior of boundary layer including transition and shock interaction, which are hardly managed by the conventional Reynolds-averaged Navier-Stokes approach, although there needs to be more effort before achieving quantitative agreement.

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Studies on the Intertidal Macrofauna Community at Yong-ho Bay, Busan, Korea (용호만 조간대의 동물군집에 관한 연구)

  • YI Soon Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.8 no.3
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    • pp.133-149
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    • 1975
  • 1. A quantitative ecological investigation of the intertidal sand beach at Yong-ho Bay, located about 6km NE of Busan Harbour was carried out from February, 1974 to February, 1975. Composition of the fauna, diversity, faunal affinity and distributions in time and space were studied. Some ecological factors influencing to the community also discussed. 2. The beach can be classified as a fine-sand beach which is dominated by Armandia lanceolata and Nephtys sp. (A). Thirty two species of animals representing 29 genera were found. In number, two polychaetes, A. lanceolata and Nephtys sp. (A) were dominant, while one polychaete, Neanthes japonica and one bivalvia, Laternula limicela were dominant in weight. 3. Distribution of the fauna was devided into three areas of different faunal compositions with sediment types particularly by mud fraction content, and it well agreed with faunal affinity and diversity index value. 4. Seasonal fluctuation of the three dominant species, A. lanceolata, Nephtys sp. (A) and N. japonica was studied. Except Nephtys sp. (A), the fluctuation were closely related to the brooding time. 5. There was no relationship between faunal distribution and organic matter content. Submergence time affected the distribution of some species but the influence to the whole-community was little.

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A Search for the Factor on Productivity Fluctuation in Korean Manufacturing Industries (우리나라 제조업의 생산성 변동원인 규명)

  • 강규철
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.22 no.51
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    • pp.175-187
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    • 1999
  • The notion of productivity has been extended from the quantitative change of input factors to the efficiency change meaning efficient use of resources, and to the technical change meaning the qualitative improvement of input resources. In this way, the technical change is termed as total factor productivity in the individual businesses or the manufacturing industries. They should efficiently respond to the variations of economic environment and at the same time, have to make the efforts to improve productivity by increasing managerial efficiency and rasing the level of technology change for the continuous growth. Considering the growing importance of productivity, this study closely examines the factors influctuation on the productivity, fluctuation using total factor productivity in korean manufacturing industries. For the objective this study investigates the methods of measurement about total factor productivity, establishes the hypotheses based on the preceding research and finding. The results are obtained through the examination on the outcoms of regression analysis and related data. The results can be summarized as follows, First, in the progress of korean industrialization, the qualitative growth does not depend on the total factor productivity of the technical advance, and does not lead to the industry expansion. That is, the contribution of total factor productivity turns out to be relatively low. Second, it is necessary for the manufacturing industry to improve the level of technology and to emphasize the innovation of business, since the capital investment does not completely become fixed in the growth rate of productivity. Finally, continuous R&D investment should be made to increase total factor productivity. Namely, the regulation of industrial structure with an intensive technical development is essential and should be based on scientific and technical knowledge.

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Trends in the Growth of Literature on Hepatitis(1984-2003): Quantitative Analysis (간염에 관한 문헌의 증가추세(1984-2003): 계량적 분석)

  • Babu, B. Ramesh;Ramakrishnan, J.
    • Journal of Korean Library and Information Science Society
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    • v.38 no.2
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    • pp.31-50
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    • 2007
  • This paper presents a scientometric analysis of the growth of literature output in the field of Hepatitis covered in three bibliographic databases namely MEDLINE, CINAHL and IPA. The literature covered in three databases for the period 1984-2003 was considered. MEDLINE covered the maximum of 75750 records during the study period 1984 to 2003. This is followed by CINAHL and IPA databases. It is found that the annual growth rate of literature in a particular field of knowledge will not be uniform and in order to measure the rate of growth from year after year, the application of RGR is quite appropriate. The RGR has shown a decreasing trend, with a slight fluctuation of growth rate for the years 1985 and 1997. The output by colleges, universities, corporate sector and research institutions with reference to RGR and Dt has shown mixed results such as increasing trend, decreasing trend and fluctuation trend. Hepatitis research indicates a different picture when the RGR and Dt were calculated by year-wise both in terms of number of papers and number of pages.

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Evaluation of Drought Effect on Groundwater System using Groundwater Level Data in Jeju Island (지하수위 자료를 이용한 제주도 지하수계의 가뭄 영향 평가)

  • Song, Sung-Ho;Lee, Byung-Sun;Choi, Kwang-Jun;Kim, Jin-Sung;Kim, Gi-Pyo
    • Journal of Environmental Science International
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    • v.23 no.4
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    • pp.637-647
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    • 2014
  • Quantitative assessment of groundwater level change under extreme event is important since groundwater system is directly affected by drought. Substantially, groundwater level fluctuation reveals to be delayed from several hours to few months after raining according to the aquifer characteristics. Groundwater system in Jeju Island would be also affected by drought and almost all regions were suffered from a severe drought during summer season (July to September) in 2013. To estimate the effect of precipitation to groundwater system, monthly mean groundwater levels in 2013 compared to those in the past from 48 monitoring wells belong to be largely affected by rainfall(Dr) over Jeju Island were analyzed. Mean groundwater levels during summer season recorded 100 mm lowered of precipitation compared to the past 30 years became decreased to range from 2.63 m to 5.42 m in southern region compared to the past and continued to December. These decreasing trends are also found in western(from -1.21 m to -4.06 m), eastern(-0.91 m to -3.24 m), and northern region(from 0.58 m to -4.02 m), respectively. Moreover, the response of groundwater level from drought turned out to be -3.80 m in August after delaying about one month. Therefore, severe drought in 2013 played an important role on groundwater system in Jeju Island and the effect of drought for groundwater level fluctuation was higher in southern region than other ones according to the regional difference of precipitation decrease.

Measuring depth of anesthesia with Bispectrum and DFA analysis of the EEG (뇌파의 바이스펙트럼과 DFA 분석을 이용한 마취심도 측정)

  • Ye, Soo-Young;Eum, Sang-hee
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.397-400
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    • 2015
  • Due to the anesthesia process is inappropriate on the operation, awakening state was appeared. Because of that patients suffered from severe mental and physical pain. To prevent the state, it is necessary to monitor the patients by measuring the depth of anesthesia. In this study, we investigate the possibility of the development of actual surgery available quantitative indicators. The DFA(detrended fluctuation analysis) which is included the correlation property of the EEG is used to analysis the depth of anesthesia and bispctrum index. In the results, at the pre-operation, the peak of bispectrum was widely distributed, DFA value was decreased. At the during operation, bispectrum was concentrically appeared in the low frequency area. At the post operation, bispectrum and DFA was both returned to the pre-operation state. As a result, we confirmed to be close correlation between the peaks of the bispectrum and DFA value.

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Study on the Status Change in Rural Landscape Planning and Landscape Project in the General Agriculture Fishing Village Development Project (일반농산어촌개발사업에 있어 농촌경관계획과 경관사업부문의 위상변화에 관한 연구)

  • Lee, Su Hyun;Cho, Tong Buhm
    • Journal of Korean Society of Rural Planning
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    • v.25 no.4
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    • pp.119-128
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    • 2019
  • Although the General Agricultural Fishing Village Development Project had a significant impact on the landscape formation and management in rural area, the rural landscape planning and project sectors was not stable by fluctuation variables. On the basic understanding the institutional status of rural landscape planning, some conclusions could be discussed as follows through the analysis of quantitative and qualitative changes and the background factors. The rural landscape plan lacked its own legal and institutional foundations, and the landscape project of the General Agricultural Fishing Village Development Project was mainly focused on the environment-improving H/W project for expanding the basic living infrastructures. In order to reflect the characteristics of the region and become independent rural landscape management, it is necessary to change the contents so that the S/W business such as the deepening landscape awareness and empowerment linked with improving the physical landscape. To this end, it is necessary to establish a foundation for the rural landscape planning system to have its own status, and it seems to seek to supplement with what is included S/W contents reflecting the context of higher level landscape planning. The landscape sector of the General Agricultural Fishing Village Development Project proved to be in the process of shrinking in both quantity and quality, despite the temporary expansion in the past. In addition, considering the distortion of the contents of landscape projects in rural sites, it seems that the rural landscape-related public project are now in a position to seek a new phase change beyond quantitative expansion. In particular, along with institutional improvements to secure the independent status of rural landscape planning that contributes to village community regeneration and social sustainability through the role of intermediary support organizations in landscape management activities. Through the integrated landscape plan, which is established in advance and led by the residents in the early stages, there is a need to change the direction to enhance meaning of the landscape planning goes beyond the facility design or space improvement.