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1

Volume analysis of treatment response of head and neck lesions using 3D level set segmentation  

NASA Astrophysics Data System (ADS)

A computerized system for segmenting lesions in head and neck CT scans was developed to assist radiologists in estimation of the response to treatment of malignant lesions. The system performs 3D segmentations based on a level set model and uses as input an approximate bounding box for the lesion of interest. In this preliminary study, CT scans from a pre-treatment exam and a post one-cycle chemotherapy exam of 13 patients containing head and neck neoplasms were used. A radiologist marked 35 temporal pairs of lesions. 13 pairs were primary site cancers and 22 pairs were metastatic lymph nodes. For all lesions, a radiologist outlined a contour on the best slice on both the pre- and post treatment scans. For the 13 primary lesion pairs, full 3D contours were also extracted by a radiologist. The average pre- and post-treatment areas on the best slices for all lesions were 4.5 and 2.1 cm2, respectively. For the 13 primary site pairs the average pre- and post-treatment primary lesions volumes were 15.4 and 6.7 cm 3 respectively. The correlation between the automatic and manual estimates for the pre-to-post-treatment change in area for all 35 pairs was r=0.97, while the correlation for the percent change in area was r=0.80. The correlation for the change in volume for the 13 primary site pairs was r=0.89, while the correlation for the percent change in volume was r=0.79. The average signed percent error between the automatic and manual areas for all 70 lesions was 11.0+/-20.6%. The average signed percent error between the automatic and manual volumes for all 26 primary lesions was 37.8+/-42.1%. The preliminary results indicate that the automated segmentation system can reliably estimate tumor size change in response to treatment relative to radiologist's hand segmentation.

Hadjiiski, Lubomir; Street, Ethan; Sahiner, Berkman; Gujar, Sachin; Ibrahim, Mohannad; Chan, Heang-Ping; Mukherji, Suresh K.

2008-03-01

2

NSEG, a segmented mission analysis program for low and high speed aircraft. Volume 1: Theoretical development  

NASA Technical Reports Server (NTRS)

A rapid mission analysis code based on the use of approximate flight path equations of motion is presented. Equation form varies with the segment type, for example, accelerations, climbs, cruises, descents, and decelerations. Realistic and detailed characteristics were specified in tabular form. The code also contains extensive flight envelope performance mapping capabilities. Approximate take off and landing analyses were performed. At high speeds, centrifugal lift effects were accounted for. Extensive turbojet and ramjet engine scaling procedures were incorporated in the code.

Hague, D. S.; Rozendaal, H. L.

1977-01-01

3

NSEG: A segmented mission analysis program for low and high speed aircraft. Volume 3: Demonstration problems  

NASA Technical Reports Server (NTRS)

Program NSEG is a rapid mission analysis code based on the use of approximate flight path equations of motion. Equation form varies with the segment type, for example, accelerations, climbs, cruises, descents, and decelerations. Realistic and detailed vehicle characteristics are specified in tabular form. In addition to its mission performance calculation capabilities, the code also contains extensive flight envelope performance mapping capabilities. For example, rate-of-climb, turn rates, and energy maneuverability parameter values may be mapped in the Mach-altitude plane. Approximate take off and landing analyses are also performed. At high speeds, centrifugal lift effects are accounted for. Extensive turbojet and ramjet engine scaling procedures are incorporated in the code.

Hague, D. S.; Rozendaal, H. L.

1977-01-01

4

Inter-sport variability of muscle volume distribution identified by segmental bioelectrical impedance analysis in four ball sports  

PubMed Central

The aim of this study was to evaluate and quantify differences in muscle distribution in athletes of various ball sports using segmental bioelectrical impedance analysis (SBIA). Participants were 115 male collegiate athletes from four ball sports (baseball, soccer, tennis, and lacrosse). Percent body fat (%BF) and lean body mass were measured, and SBIA was used to measure segmental muscle volume (MV) in bilateral upper arms, forearms, thighs, and lower legs. We calculated the MV ratios of dominant to nondominant, proximal to distal, and upper to lower limbs. The measurements consisted of a total of 31 variables. Cluster and factor analyses were applied to identify redundant variables. The muscle distribution was significantly different among groups, but the %BF was not. The classification procedures of the discriminant analysis could correctly distinguish 84.3% of the athletes. These results suggest that collegiate ball game athletes have adapted their physique to their sport movements very well, and the SBIA, which is an affordable, noninvasive, easy-to-operate, and fast alternative method in the field, can distinguish ball game athletes according to their specific muscle distribution within a 5-minute measurement. The SBIA could be a useful, affordable, and fast tool for identifying talents for specific sports. PMID:24379714

Yamada, Yosuke; Masuo, Yoshihisa; Nakamura, Eitaro; Oda, Shingo

2013-01-01

5

Misclassified Tissue Volumes in Alzheimer Disease Patients With White Matter Hyperintensities Importance of Lesion Segmentation Procedures for Volumetric Analysis  

Microsoft Academic Search

Background and Purpose—MRI-based quantification of gray and white matter volume is common in studies involving elderly patient populations. The aim of the present study was to describe the effects of not accounting for subcortical white matter hyperintensities (WMH) on tissue volumes in Alzheimer Disease patients with varying degrees of WMH (mild: n19, moderate: n22, severe: n18). Methods—An automated tissue segmentation

Naama Levy-Cooperman; Joel Ramirez; Nancy J. Lobaugh; Sandra E. Black

2010-01-01

6

Segmentation strategies for polymerized volume data sets  

E-print Network

A new technique, called the polymerization algorithm, is described for the hierarchical segmentation of polymerized volume data sets (PVDS) using the Lblock data structure. The Lblock data structure is defined as a 3dimensional isorectangular block...

Doddapaneni, Venkata Purna

2006-04-12

7

Effect of body mass index (BMI) on estimation of extracellular volume (ECV) in hemodialysis (HD) patients using segmental and whole body bioimpedance analysis  

Microsoft Academic Search

The aim of the study was to investigate whether body mass index (BMI) influences the estimation of extracellular volume (ECV) in hemodialysis (HD) patients when using segmental bioimpedance analysis (SBIA) compared to wrist-to-ankle bioimpedance analysis (WBIA) during HD with ultrafiltration (UF). Twenty five HD patients (M:F 19:6,) were studied, and further subdivided into two groups of patients, one group with

Mary Carter; Alice T. Morris; Fansan Zhu; Wojciech Zaluska; Nathan W. Levin

2005-01-01

8

Independent Component Analysis Segmentation Algorithm  

Microsoft Academic Search

In this paper we propose and investigate a new segmentation algorithm called the ICA (independent component analysis) segmentation algorithm and compare it against other existing overlapping strokes segmentation algorithms. The ICA segmentation algorithm converts the original touching or overlapping word components into a blind source matrix and then calculates the weighted value matrix before the values are re-evaluated using a

Yan Chen; Graham Leedham

2005-01-01

9

NSEG: A segmented mission analysis program for low and high speed aircraft. Volume 2: Program users manual  

NASA Technical Reports Server (NTRS)

A rapid mission analysis code based on the use of approximate flight path equations of motion is described. Equation form varies with the segment type, for example, accelerations, climbs, cruises, descents, and decelerations. Realistic and detailed vehicle characteristics are specified in tabular form. In addition to its mission performance calculation capabilities, the code also contains extensive flight envelop performance mapping capabilities. Approximate take off and landing analyses can be performed. At high speeds, centrifugal lift effects are taken into account. Extensive turbojet and ramjet engine scaling procedures are incorporated in the code.

Hague, D. S.; Rozendaal, H. L.

1977-01-01

10

Automated volume analysis of head and neck lesions on CT scans using 3D level set segmentation  

SciTech Connect

The authors have developed a semiautomatic system for segmentation of a diverse set of lesions in head and neck CT scans. The system takes as input an approximate bounding box, and uses a multistage level set to perform the final segmentation. A data set consisting of 69 lesions marked on 33 scans from 23 patients was used to evaluate the performance of the system. The contours from automatic segmentation were compared to both 2D and 3D gold standard contours manually drawn by three experienced radiologists. Three performance metric measures were used for the comparison. In addition, a radiologist provided quality ratings on a 1 to 10 scale for all of the automatic segmentations. For this pilot study, the authors observed that the differences between the automatic and gold standard contours were larger than the interobserver differences. However, the system performed comparably to the radiologists, achieving an average area intersection ratio of 85.4% compared to an average of 91.2% between two radiologists. The average absolute area error was 21.1% compared to 10.8%, and the average 2D distance was 1.38 mm compared to 0.84 mm between the radiologists. In addition, the quality rating data showed that, despite the very lax assumptions made on the lesion characteristics in designing the system, the automatic contours approximated many of the lesions very well.

Street, Ethan; Hadjiiski, Lubomir; Sahiner, Berkman; Gujar, Sachin; Ibrahim, Mohannad; Mukherji, Suresh K.; Chan, Heang-Ping [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-0904 (United States)

2007-11-15

11

Contour Segment Analysis for Human Silhouette Pre-segmentation  

E-print Network

Contour Segment Analysis for Human Silhouette Pre-segmentation Cyrille Migniot, Pascal Bertolino of being part of a human silhouette. . .. 1 Introduction Simultaneous detection and segmentation of element the presence of a person in the window. With HOG local process, information relied on the person silhouette

Paris-Sud XI, Université de

12

Bioimpedance Measurement of Segmental Fluid Volumes and Hemodynamics  

NASA Technical Reports Server (NTRS)

Bioimpedance has become a useful tool to measure changes in body fluid compartment volumes. An Electrical Impedance Spectroscopic (EIS) system is described that extends the capabilities of conventional fixed frequency impedance plethysmographic (IPG) methods to allow examination of the redistribution of fluids between the intracellular and extracellular compartments of body segments. The combination of EIS and IPG techniques was evaluated in the human calf, thigh, and torso segments of eight healthy men during 90 minutes of six degree head-down tilt (HDT). After 90 minutes HDT the calf and thigh segments significantly (P < 0.05) lost conductive volume (eight and four percent, respectively) while the torso significantly (P < 0.05) gained volume (approximately three percent). Hemodynamic responses calculated from pulsatile IPG data also showed a segmental pattern consistent with vascular fluid loss from the lower extremities and vascular engorgement in the torso. Lumped-parameter equivalent circuit analyses of EIS data for the calf and thigh indicated that the overall volume decreases in these segments arose from reduced extracellular volume that was not completely balanced by increased intracellular volume. The combined use of IPG and EIS techniques enables noninvasive tracking of multi-segment volumetric and hemodynamic responses to environmental and physiological stresses.

Montgomery, Leslie D.; Wu, Yi-Chang; Ku, Yu-Tsuan E.; Gerth, Wayne A.; DeVincenzi, D. (Technical Monitor)

2000-01-01

13

Partial volume effect modeling for segmentation and tissue classification of brain magnetic resonance images: A review.  

PubMed

Quantitative analysis of magnetic resonance (MR) brain images are facilitated by the development of automated segmentation algorithms. A single image voxel may contain of several types of tissues due to the finite spatial resolution of the imaging device. This phenomenon, termed partial volume effect (PVE), complicates the segmentation process, and, due to the complexity of human brain anatomy, the PVE is an important factor for accurate brain structure quantification. Partial volume estimation refers to a generalized segmentation task where the amount of each tissue type within each voxel is solved. This review aims to provide a systematic, tutorial-like overview and categorization of methods for partial volume estimation in brain MRI. The review concentrates on the statistically based approaches for partial volume estimation and also explains differences to other, similar image segmentation approaches. PMID:25431640

Tohka, Jussi

2014-11-28

14

Volume Measurement of the Intracranial Aneurysm: A Discussion and Comparison of the Alternatives to Manual Segmentation  

PubMed Central

Objective Several modalities are available for volumetric measurement of the intracranial aneurysm. We discuss the challenges involved in manual segmentation, and analyze the application of alternative methods using automatic segmentation and geometric formulae in measurement of aneurysm volumes and coil packing density. Methods The volumes and morphology of 38 aneurysms treated with endovascular coiling at a single center were measured using three-dimensional rotational angiography (3DRA) reconstruction software using automatic segmentation. Aneurysm volumes were also calculated from their height, width, depth, size of neck, and assumed shape in 3DRA images using simple geometric formulae. The aneurysm volumes were dichotomized as "small" or "large" using the median volume of the studied population (54 mm3) measured by automatic segmentation as the cut-off value for further statistical analysis. Results A greater proportion of aneurysms were categorized as being "small" when geometric formulae were applied. The median aneurysm volumes obtained were 54.5 mm3 by 3DRA software, and 30.6 mm3 using mathematical equations. An underestimation of aneurysm volume with a resultant overestimation in the calculated coil packing density (p = 0.002) was observed. Conclusion Caution must be exercised in the application of simple geometric formulae in the management of intracranial aneurysms as volumes may potentially be underestimated and packing densities falsely elevated. Future research should focus on validation of automatic segmentation in volumetric measurement and improving its accuracy to enhance its application in clinical practice.

Wong, Kai-Sing Alain; Woo, Yat-Ming Peter; Chan, Kwong-Yau; Leung, Kar-Ming

2014-01-01

15

Semantic Analysis for Topical Segmentation of Videos  

Microsoft Academic Search

Topic segmentation of videos enables topic-based categorization, retrieval and browsing and also facilitates efficient video authoring. Existing video topic segmentation techniques, however, are domain specific to news or narrative videos while generic approaches based on video shot analysis generate too fine-grained micro-segments. This paper addresses this challenge through a multi-modal semantic analysis technique for recognizing topical segments. We analyze the

Ying Li

2007-01-01

16

Uterine fibroid segmentation and volume measurement on MRI  

NASA Astrophysics Data System (ADS)

Uterine leiomyomas are the most common pelvic tumors in females. The efficacy of medical treatment is gauged by shrinkage of the size of these tumors. In this paper, we present a method to robustly segment the fibroids on MRI and accurately measure the 3D volume. Our method is based on a combination of fast marching level set and Laplacian level set. With a seed point placed inside the fibroid region, a fast marching level set is first employed to obtain a rough segmentation, followed by a Laplacian level set to refine the segmentation. We devised a scheme to automatically determine the parameters for the level set function and the sigmoid function based on pixel statistics around the seed point. The segmentation is conducted on three concurrent views (axial, coronal and sagittal), and a combined volume measurement is computed to obtain a more reliable measurement. We carried out extensive tests on 13 patients, 25 MRI studies and 133 fibroids. The segmentation result was validated against manual segmentation defined by experts. The average segmentation sensitivity (true positive fraction) among all fibroids was 84.6%, and the average segmentation specificity (1-false positive fraction) was 84.3%.

Yao, Jianhua; Chen, David; Lu, Wenzhu; Premkumar, Ahalya

2006-03-01

17

Iterative threshold segmentation for PET target volume delineation  

SciTech Connect

The purpose of this work is to create a rigorous method of segmenting PET images using an automated iterative technique. To this end a phantom study employing spherical targets was used to determine local (slice specific) threshold levels which produce correct cross-sections based on the contrast between target and background. Numerous target to background activity concentration ratios were investigated but found to have minimal effect in comparison to the influence of target size. Functions were fit to this data and used to construct an iterative threshold segmentation algorithm. In all cases this approach yielded convergence within ten iterations. Iterative threshold segmentation was applied using both an axial and tri-axial approach to the spherical targets and also to two irregularly shaped volumes. Of these two approaches, the tri-axial method proved less susceptible to image noise and better at dealing with partial volume effects at the interface between target and background. For comparative purposes, single thresholds of 28% and 40% were also applied to the spherical data sets. The tri-axial iterative method was found capable of delineating cross sections with areas greater than 250 mm{sup 2} to within the maximum resolution possible (1 pixel width). Cross sections of less than 250 mm{sup 2} in area were resolved by the tri-axial method to within 2 pixel widths of their true physical extent. Local contrast based iterative threshold segmentation shows promise as a method of rigorously delineating PET target volumes with good accuracy subject to the limitations imposed by the image resolution which currently characterizes this modality.

Drever, Laura; Roa, Wilson; McEwan, Alexander; Robinson, Don [Department of Medical Physics, BC Cancer Agency, Victoria, British Columbia, V8R 6V5 (Canada); Department of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta, T6G 1Z2 (Canada); Department of Oncologic Imaging, Cross Cancer Institute, Edmonton, Alberta, T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, T6G 1Z2 (Canada)

2007-04-15

18

Artificial Neural Network-Based System for PET Volume Segmentation.  

PubMed

Tumour detection, classification, and quantification in positron emission tomography (PET) imaging at early stage of disease are important issues for clinical diagnosis, assessment of response to treatment, and radiotherapy planning. Many techniques have been proposed for segmenting medical imaging data; however, some of the approaches have poor performance, large inaccuracy, and require substantial computation time for analysing large medical volumes. Artificial intelligence (AI) approaches can provide improved accuracy and save decent amount of time. Artificial neural networks (ANNs), as one of the best AI techniques, have the capability to classify and quantify precisely lesions and model the clinical evaluation for a specific problem. This paper presents a novel application of ANNs in the wavelet domain for PET volume segmentation. ANN performance evaluation using different training algorithms in both spatial and wavelet domains with a different number of neurons in the hidden layer is also presented. The best number of neurons in the hidden layer is determined according to the experimental results, which is also stated Levenberg-Marquardt backpropagation training algorithm as the best training approach for the proposed application. The proposed intelligent system results are compared with those obtained using conventional techniques including thresholding and clustering based approaches. Experimental and Monte Carlo simulated PET phantom data sets and clinical PET volumes of nonsmall cell lung cancer patients were utilised to validate the proposed algorithm which has demonstrated promising results. PMID:20936152

Sharif, Mhd Saeed; Abbod, Maysam; Amira, Abbes; Zaidi, Habib

2010-01-01

19

Artificial Neural Network-Based System for PET Volume Segmentation  

PubMed Central

Tumour detection, classification, and quantification in positron emission tomography (PET) imaging at early stage of disease are important issues for clinical diagnosis, assessment of response to treatment, and radiotherapy planning. Many techniques have been proposed for segmenting medical imaging data; however, some of the approaches have poor performance, large inaccuracy, and require substantial computation time for analysing large medical volumes. Artificial intelligence (AI) approaches can provide improved accuracy and save decent amount of time. Artificial neural networks (ANNs), as one of the best AI techniques, have the capability to classify and quantify precisely lesions and model the clinical evaluation for a specific problem. This paper presents a novel application of ANNs in the wavelet domain for PET volume segmentation. ANN performance evaluation using different training algorithms in both spatial and wavelet domains with a different number of neurons in the hidden layer is also presented. The best number of neurons in the hidden layer is determined according to the experimental results, which is also stated Levenberg-Marquardt backpropagation training algorithm as the best training approach for the proposed application. The proposed intelligent system results are compared with those obtained using conventional techniques including thresholding and clustering based approaches. Experimental and Monte Carlo simulated PET phantom data sets and clinical PET volumes of nonsmall cell lung cancer patients were utilised to validate the proposed algorithm which has demonstrated promising results. PMID:20936152

Sharif, Mhd Saeed; Abbod, Maysam; Amira, Abbes; Zaidi, Habib

2010-01-01

20

Segmentation of 3D CT Volume Images Using a Single 2D Atlas  

E-print Network

Segmentation of 3D CT Volume Images Using a Single 2D Atlas Feng Ding1 , Wee Kheng Leow1 on the segmentation of complex CT/MR images using the atlas-based approach. Most existing methods use 3D atlases which for the segmentation of brain images. This paper presents a method that can segment multiple slices of an abdominal CT

Leow, Wee Kheng

21

A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging  

NASA Astrophysics Data System (ADS)

This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51? ± ?1.92) to (97.27? ± ?0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development.

Martin, Spencer; Brophy, Mark; Palma, David; Louie, Alexander V.; Yu, Edward; Yaremko, Brian; Ahmad, Belal; Barron, John L.; Beauchemin, Steven S.; Rodrigues, George; Gaede, Stewart

2015-02-01

22

A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging.  

PubMed

This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51? ± ?1.92) to (97.27? ± ?0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development. PMID:25611494

Martin, Spencer; Brophy, Mark; Palma, David; Louie, Alexander V; Yu, Edward; Yaremko, Brian; Ahmad, Belal; Barron, John L; Beauchemin, Steven S; Rodrigues, George; Gaede, Stewart

2015-02-21

23

3D defect segmentation on CT volume data using morphology and resample techniques.  

PubMed

Segmentation of CT volume data is important and useful in non-destructive testing and evaluating. To eliminate the artifacts influence, we propose a new approach of 3D defect segmentation using two steps. First of all, an initial segmentation using 3D morphological method is performed. The initial segmentation results include false defects. Secondly, resample in polar coordinates method is performed. The experimental results prove that our method is effective to correctly segment 3D defects and eliminate false segmentation. Some experiments on CT volume data with noise are made, the results show that our method is also useful. PMID:24191991

Zou, Yongning; Wang, Jue; Li, Jianwei

2013-01-01

24

Applicability of single muscle CSA for predicting segmental muscle volume in young men.  

PubMed

The present study aimed to evaluate the applicability of using a single slice cross-sectional area (CSA) of the skeletal muscle for estimating segmental skeletal muscle volume (SMV). By using MRI, the SMV of each of the upper arm, lower arm, upper leg, lower leg, and trunk was determined in 29 males. First, step-wise multiple regression analysis was applied to develop the equation for each segmental SMV in which the CSAs at intervals of 10% of segment length (SL) were used as independent variables. Second, simple linear regression analysis with every CSA selected in the first step was applied to predict SMV in each body segment. In each segment, the standard error of estimate (SEE) in the simple linear regression equation was greater than that in the multiple regression one. The most appropriate slice level for measuring a single CSA to estimate SMV was 30% of the upper arm SL (R2=0.800, SEE=7.4%), 60% of the lower arm SL (0.788, 10.3%), 50% of the upper leg SL (0.795, 7.0%), and 20% of the trunk SL (0.813, 6.1%). For the lower leg, muscle CSAs at multiple slice levels are required to estimate SMV without the systematic error. PMID:24408770

Tanaka, N I; Kanehisa, H

2014-06-01

25

Analysis of Numerical Methods for Level Set Based Image Segmentation  

E-print Network

Analysis of Numerical Methods for Level Set Based Image Segmentation Björn Scheuermann and Bodo image segmentation. The Chan-Vese functional for image segmentation is a general and popular variational as on real images. Furthermore, the performance of the approaches is evaluated in a segmentation benchmark

26

Brain tumor target volume determination for radiation therapy treatment planning through the use of automated MRI segmentation  

NASA Astrophysics Data System (ADS)

Radiation therapy seeks to effectively irradiate the tumor cells while minimizing the dose to adjacent normal cells. Prior research found that the low success rates for treating brain tumors would be improved with higher radiation doses to the tumor area. This is feasible only if the target volume can be precisely identified. However, the definition of tumor volume is still based on time-intensive, highly subjective manual outlining by radiation oncologists. In this study the effectiveness of two automated Magnetic Resonance Imaging (MRI) segmentation methods, k-Nearest Neighbors (kNN) and Knowledge-Guided (KG), in determining the Gross Tumor Volume (GTV) of brain tumors for use in radiation therapy was assessed. Three criteria were applied: accuracy of the contours; quality of the resulting treatment plan in terms of dose to the tumor; and a novel treatment plan evaluation technique based on post-treatment images. The kNN method was able to segment all cases while the KG method was limited to enhancing tumors and gliomas with clear enhancing edges. Various software applications were developed to create a closed smooth contour that encompassed the tumor pixels from the segmentations and to integrate these results into the treatment planning software. A novel, probabilistic measurement of accuracy was introduced to compare the agreement of the segmentation methods with the weighted average physician volume. Both computer methods under-segment the tumor volume when compared with the physicians but performed within the variability of manual contouring (28% +/- 12% for inter-operator variability). Computer segmentations were modified vertically to compensate for their under-segmentation. When comparing radiation treatment plans designed from physician-defined tumor volumes with treatment plans developed from the modified segmentation results, the reference target volume was irradiated within the same level of conformity. Analysis of the plans based on post-treatment MRI showed that the segmentation plans provided similar dose coverage to areas being treated by the original treatment plans. This research demonstrates that computer segmentations provide a feasible route to automatic target volume definition. Because of the lower variability and greater efficiency of the automated techniques, their use could lead to more precise plans and better prognosis for brain tumor patients.

Mazzara, Gloria Patrika

27

Image Segmentation Analysis for NASA Earth Science Applications  

NASA Technical Reports Server (NTRS)

NASA collects large volumes of imagery data from satellite-based Earth remote sensing sensors. Nearly all of the computerized image analysis of this data is performed pixel-by-pixel, in which an algorithm is applied directly to individual image pixels. While this analysis approach is satisfactory in many cases, it is usually not fully effective in extracting the full information content from the high spatial resolution image data that s now becoming increasingly available from these sensors. The field of object-based image analysis (OBIA) has arisen in recent years to address the need to move beyond pixel-based analysis. The Recursive Hierarchical Segmentation (RHSEG) software developed by the author is being used to facilitate moving from pixel-based image analysis to OBIA. The key unique aspect of RHSEG is that it tightly intertwines region growing segmentation, which produces spatially connected region objects, with region object classification, which groups sets of region objects together into region classes. No other practical, operational image segmentation approach has this tight integration of region growing object finding with region classification This integration is made possible by the recursive, divide-and-conquer implementation utilized by RHSEG, in which the input image data is recursively subdivided until the image data sections are small enough to successfully mitigat the combinatorial explosion caused by the need to compute the dissimilarity between each pair of image pixels. RHSEG's tight integration of region growing object finding and region classification is what enables the high spatial fidelity of the image segmentations produced by RHSEG. This presentation will provide an overview of the RHSEG algorithm and describe how it is currently being used to support OBIA or Earth Science applications such as snow/ice mapping and finding archaeological sites from remotely sensed data.

Tilton, James C.

2010-01-01

28

Segmented ray casting for data parallel volume rendering  

Microsoft Academic Search

Interactive volume rendering is important for the timely analysis of three-dimensional data, but workstations take seconds to minutes to render data sets of a few megabytes. We have developed a parallel ray-casting technique. called Sepnenred Ray Cnsting, which can render a 128x128~128 data set at 2-3 frames per second on a 4K processor DECmpp 12OOO\\/Sx Model 100. Pixel values in

William M. Hsu

1993-01-01

29

Customer Segmentation Model Based on Retail Consumer Behavior Analysis  

Microsoft Academic Search

Customer segmentation is the basis of the customer relationship management (CRM). For the retail business, customer segmentation through certain methods will help the good implementation of customer relationship management. The customer segmentation based on the purchase behavior may bean effective method of choice. Principal component analysis (PCA) is a method of multivariate statistical analysis. BP neural network is a multilayer

Minghua Han

2008-01-01

30

A comparison of automated segmentation and manual tracing for quantifying hippocampal and amygdala volumes?  

PubMed Central

Large databases of high-resolution structural MR images are being assembled to quantitatively examine the relationships between brain anatomy, disease progression, treatment regimens, and genetic influences upon brain structure. Quantifying brain structures in such large databases cannot be practically accomplished by expert neuroanatomists using hand-tracing. Rather, this research will depend upon automated methods that reliably and accurately segment and quantify dozens of brain regions. At present, there is little guidance available to help clinical research groups in choosing such tools. Thus, our goal was to compare the performance of two popular and fully automated tools, FSL/FIRST and FreeSurfer, to expert hand tracing in the measurement of the hippocampus and amygdala. Volumes derived from each automated measurement were compared to hand tracing for percent volume overlap, percent volume difference, across-sample correlation, and 3-D group-level shape analysis. In addition, sample size estimates for conducting between-group studies were computed for a range of effect sizes. Compared to hand tracing, hippocampal measurements with FreeSurfer exhibited greater volume overlap, smaller volume difference, and higher correlation than FIRST, and sample size estimates with FreeSurfer were closer to hand tracing. Amygdala measurement with FreeSurfer was also more highly correlated to hand tracing than FIRST, but exhibited a greater volume difference than FIRST. Both techniques had comparable volume overlap and similar sample size estimates. Compared to hand tracing, a 3-D shape analysis of the hippocampus showed FreeSurfer was more accurate than FIRST, particularly in the head and tail. However, FIRST more accurately represented the amygdala shape than FreeSurfer, which inflated its anterior and posterior surfaces. PMID:19162198

Morey, Rajendra A.; Petty, Christopher M.; Xu, Yuan; Hayes, Jasmeet Pannu; Wagner, H. Ryan; Lewis, Darrell V.; LaBar, Kevin S.; Styner, Martin; McCarthy, Gregory

2009-01-01

31

Greedy modular subspace segment principle component analysis  

NASA Astrophysics Data System (ADS)

Hyperspectral images collect hundreds of co-registered images of the earth surface with different wavelengths in visible and short-wave inferred region. With such high spectral resolution, many adjacent bands are highly correlated, i.e., they contain a lot redundant information. How to remove unnecessary information from this huge amount of data and preserve all the information is a challenging problem. Principal component analysis (PCA) is one of the widely used algorithms for this problem. It assumes the larger variance contains the most information, so it projects the data into the direction to maximize the variance. Most of the signals will be kept in the first several principal components, and the rest will be considered to be noise and neglected. To further reduce the redundancy, segment PCA is proposed, which first separate the whole spectral bands into blocks and then perform the original PCA in each block individually. Both these two approaches perform well for data compression, but for image classification in its feature space, they did not achieve comparable results. In this study, we adopt the greedy modular subspaces transformation (GMST) to find the optimal feature subspace for the segment PCA. It is expected to provide a comparable classification results with high compression performance.

Chen, Hsin-Ting; Ren, Hsuan; Chang, Yang-Lang

2007-09-01

32

3D robust Chan-Vese model for industrial computed tomography volume data segmentation  

NASA Astrophysics Data System (ADS)

Industrial computed tomography (CT) has been widely applied in many areas of non-destructive testing (NDT) and non-destructive evaluation (NDE). In practice, CT volume data to be dealt with may be corrupted by noise. This paper addresses the segmentation of noisy industrial CT volume data. Motivated by the research on the Chan-Vese (CV) model, we present a region-based active contour model that draws upon intensity information in local regions with a controllable scale. In the presence of noise, a local energy is firstly defined according to the intensity difference within a local neighborhood. Then a global energy is defined to integrate local energy with respect to all image points. In a level set formulation, this energy is represented by a variational level set function, where a surface evolution equation is derived for energy minimization. Comparative analysis with the CV model indicates the comparable performance of the 3D robust Chan-Vese (RCV) model. The quantitative evaluation also shows the segmentation accuracy of 3D RCV. In addition, the efficiency of our approach is validated under several types of noise, such as Poisson noise, Gaussian noise, salt-and-pepper noise and speckle noise.

Liu, Linghui; Zeng, Li; Luan, Xiao

2013-11-01

33

Midbrain volume segmentation using active shape models and LBPs  

NASA Astrophysics Data System (ADS)

In recent years, the use of Magnetic Resonance Imaging (MRI) to detect different brain structures such as midbrain, white matter, gray matter, corpus callosum, and cerebellum has increased. This fact together with the evidence that midbrain is associated with Parkinson's disease has led researchers to consider midbrain segmentation as an important issue. Nowadays, Active Shape Models (ASM) are widely used in literature for organ segmentation where the shape is an important discriminant feature. Nevertheless, this approach is based on the assumption that objects of interest are usually located on strong edges. Such a limitation may lead to a final shape far from the actual shape model. This paper proposes a novel method based on the combined use of ASM and Local Binary Patterns for segmenting midbrain. Furthermore, we analyzed several LBP methods and evaluated their performance. The joint-model considers both global and local statistics to improve final adjustments. The results showed that our proposal performs substantially better than the ASM algorithm and provides better segmentation measurements.

Olveres, Jimena; Nava, Rodrigo; Escalante-Ramírez, Boris; Cristóbal, Gabriel; García-Moreno, Carla María.

2013-09-01

34

An accurate colon residue detection algorithm with partial volume segmentation  

E-print Network

is the second leading cause of cancer-related death in the United States. Earlier detection and removal) image-segmentation framework. A Markov random field (MRF) model was developed to reflect the prior Field I. Introduction Colon cancer is the second leading cause of cancer-related death in the United

35

High volume production trial of mirror segments for the Thirty Meter Telescope  

NASA Astrophysics Data System (ADS)

The Thirty Meter Telescope is a next-generation optical/infrared telescope to be constructed on Mauna Kea, Hawaii toward the end of this decade, as an international project. Its 30 m primary mirror consists of 492 off-axis aspheric segmented mirrors. High volume production of hundreds of segments has started in 2013 based on the contract between National Astronomical Observatory of Japan and Canon Inc.. This paper describes the achievements of the high volume production trials. The Stressed Mirror Figuring technique which is established by Keck Telescope engineers is arranged and adopted. To measure the segment surface figure, a novel stitching algorithm is evaluated by experiment. The integration procedure is checked with prototype segment.

Oota, Tetsuji; Negishi, Mahito; Shinonaga, Hirohiko; Gomi, Akihiko; Tanaka, Yutaka; Akutsu, Kotaro; Otsuka, Itaru; Mochizuki, Shun; Iye, Masanori; Yamashita, Takuya

2014-07-01

36

Texture segmentation and analysis for tissue characterization  

NASA Astrophysics Data System (ADS)

Early detection of tissue changes in a disease process is of utmost interest and a challenge for non-invasive imaging techniques. Texture is an important property of image regions and many texture descriptors have been proposed in the literature. In this paper we introduce a new approach related to texture descriptors and texture grouping. There exist some applications, e.g. shape from texture, that require a more dense sampling as provided by the pseudo-Wigner distribution. Therefore, the first step to the problem is to use a modular pattern detection in textured images based on the use of a Pseudo-Wigner Distribution (PWD) followed by a PCA stage. The second scheme is to consider a direct local frequency analysis by splitting the PWD spectra following a "cortex-like" structure. As an alternative technique, the use of a Gabor multiresolution approach was considered. Gabor functions constitute a family of band-pass filters that gather the most salient properties of spatial frequency and orientation selectivity. This paper presents a comparison of time-frequency methods, based on the use of the PWD, with sparse filtering approaches using a Gabor-based multiresolution representation. Performance the current methods is evaluated for the segmentation for synthetic texture mosaics and for osteoporosis images.

Redondo, Rafael; Fischer, Sylvain; Cristobal, Gabriel; Forero, Manuel; Santos, Andres; Hormigo, Javier; Gabarda, Salvador

2004-10-01

37

Comparison of EM-based and level set partial volume segmentations of MR brain images  

NASA Astrophysics Data System (ADS)

EM and level set algorithms are competing methods for segmenting MRI brain images. This paper presents a fair comparison of the two techniques using the Montreal Neurological Institute's software phantom. There are many flavors of level set algorithms for segmentation into multiple regions (multi-phase algorithms, multi-layer algorithms). The specific algorithm evaluated by us is a variant of the multi-layer level set algorithm. It uses a single level set function for segmenting the image into multiple classes and can be run to completion without restarting. The EM-based algorithm is standard. Both algorithms have the capacity to model a variable number of partial volume classes as well as image inhomogeneity (bias field). Our evaluation consists of systematically changing the number of partial volume classes, additive image noise, and regularization parameters. The results suggest that the performances of both algorithms are comparable across noise, number of partial volume classes, and regularization. The segmentation errors of both algorithms are around 5 - 10% for cerebrospinal fluid, gray and white matter. The level set algorithm appears to have a slight advantage for gray matter segmentation. This may be beneficial in studying certain brain diseases (Multiple Sclerosis or Alzheimer's disease) where small changes in gray matter volume are significant.

Tagare, Hemant D.; Chen, Yunmei; Fulbright, Robert K.

2008-03-01

38

Texture Analysis and Segmentation Using Modulation Features, Generative Models,  

E-print Network

, image segmentation, AM-FM models, demodulation, generative models, curve evolution, cue combination. Ã? 1 by combining ideas from image analysis and probabilistic modeling. We rely on AM-FM texture models and and segmentation problems: First, at the feature extraction stage, we propose a Regularized Demodulation Algorithm

Paragios, Nikos

39

Automated Retinal Vessel Segmentation Using Multiscale Analysis and Adaptive Thresholding  

Microsoft Academic Search

Computer based analysis for automated segmentation of blood vessels in retinal images helps eye care specialists screen larger populations for vessel abnormalities. Because the width of retinal vessels can vary from very large to very small, and the local contrast of vessels is unstable especially in unhealthy ocular fundus, the automated retinal segmentation is difficult. We propose a novel method

Qin Li; Jane You; Lei Zhang; Prabir Bhattacharya

2006-01-01

40

LANDSAT-D program. Volume 2: Ground segment  

NASA Technical Reports Server (NTRS)

Raw digital data, as received from the LANDSAT spacecraft, cannot generate images that meet specifications. Radiometric corrections must be made to compensate for aging and for differences in sensitivity among the instrument sensors. Geometric corrections must be made to compensate for off-nadir look angle, and to calculate spacecraft drift from its prescribed path. Corrections must also be made for look-angle jitter caused by vibrations induced by spacecraft equipment. The major components of the LANDSAT ground segment and their functions are discussed.

1984-01-01

41

Pulmonary airways tree segmentation from CT examinations using adaptive volume of interest  

NASA Astrophysics Data System (ADS)

Airways tree segmentation is an important step in quantitatively assessing the severity of and changes in several lung diseases such as chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis. It can also be used in guiding bronchoscopy. The purpose of this study is to develop an automated scheme for segmenting the airways tree structure depicted on chest CT examinations. After lung volume segmentation, the scheme defines the first cylinder-like volume of interest (VOI) using a series of images depicting the trachea. The scheme then iteratively defines and adds subsequent VOIs using a region growing algorithm combined with adaptively determined thresholds in order to trace possible sections of airways located inside the combined VOI in question. The airway tree segmentation process is automatically terminated after the scheme assesses all defined VOIs in the iteratively assembled VOI list. In this preliminary study, ten CT examinations with 1.25mm section thickness and two different CT image reconstruction kernels ("bone" and "standard") were selected and used to test the proposed airways tree segmentation scheme. The experiment results showed that (1) adopting this approach affectively prevented the scheme from infiltrating into the parenchyma, (2) the proposed method reasonably accurately segmented the airways trees with lower false positive identification rate as compared with other previously reported schemes that are based on 2-D image segmentation and data analyses, and (3) the proposed adaptive, iterative threshold selection method for the region growing step in each identified VOI enables the scheme to segment the airways trees reliably to the 4th generation in this limited dataset with successful segmentation up to the 5th generation in a fraction of the airways tree branches.

Park, Sang Cheol; Kim, Won Pil; Zheng, Bin; Leader, Joseph K.; Pu, Jiantao; Tan, Jun; Gur, David

2009-02-01

42

Exploratory analysis of genomic segmentations with Segtools  

PubMed Central

Background As genome-wide experiments and annotations become more prevalent, researchers increasingly require tools to help interpret data at this scale. Many functional genomics experiments involve partitioning the genome into labeled segments, such that segments sharing the same label exhibit one or more biochemical or functional traits. For example, a collection of ChlP-seq experiments yields a compendium of peaks, each labeled with one or more associated DNA-binding proteins. Similarly, manually or automatically generated annotations of functional genomic elements, including cis-regulatory modules and protein-coding or RNA genes, can also be summarized as genomic segmentations. Results We present a software toolkit called Segtools that simplifies and automates the exploration of genomic segmentations. The software operates as a series of interacting tools, each of which provides one mode of summarization. These various tools can be pipelined and summarized in a single HTML page. We describe the Segtools toolkit and demonstrate its use in interpreting a collection of human histone modification data sets and Plasmodium falciparum local chromatin structure data sets. Conclusions Segtools provides a convenient, powerful means of interpreting a genomic segmentation. PMID:22029426

2011-01-01

43

Cell nuclei segmentation for histopathological image analysis  

NASA Astrophysics Data System (ADS)

In this paper, we propose a supervised method for segmenting cell nuclei from background and extra-cellular regions in pathological images. To this end, we segment the cell regions from the other areas by classifying the image pixels into either cell or extra-cellular category. Instead of using pixel color intensities, the color-texture extracted at the local neighborhood of each pixel is utilized as the input to our classification algorithm. The color-texture at each pixel is extracted by local Fourier transform (LFT) from a new color space, the most discriminant color space (MDC). The MDC color space is optimized to be a linear combination of the original RGB color space so that the extracted LFT texture features in the MDC color space can achieve the most discrimination in terms of classification (segmentation) performance. To speed up the texture feature extraction process, we develop an efficient LFT extraction algorithm based on image shifting and image integral. For evaluation, our method is compared with the state-of-the-art segmentation algorithms (Graph-cut, Mean-shift, etc.). Empirical results show that our segmentation method achieves better performance than these popular methods.

Kong, Hui; Belkacem-Boussaid, Kamel; Gurcan, Metin

2011-03-01

44

Multi-Segment Hemodynamic and Volume Assessment With Impedance Plethysmography: Aerospace Applications  

NASA Technical Reports Server (NTRS)

Definition of multi-segmental circulatory and volume changes in the human body provides an understanding of the physiologic responses to various aerospace conditions. We have developed instrumentation and testing procedures at NASA Ames Research Center that may be useful in biomedical research and clinical diagnosis. Specialized two, four, and six channel impedance systems will be described that have been used to measure calf, thigh, thoracic, arm, and cerebral hemodynamic and volume changes during various experimental investigations.

Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Webbon, Bruce W. (Technical Monitor)

1995-01-01

45

Precise segmentation of multiple organs in CT volumes using learning-based approach and information theory.  

PubMed

In this paper, we present a novel method by incorporating information theory into the learning-based approach for automatic and accurate pelvic organ segmentation (including the prostate, bladder and rectum). We target 3D CT volumes that are generated using different scanning protocols (e.g., contrast and non-contrast, with and without implant in the prostate, various resolution and position), and the volumes come from largely diverse sources (e.g., diseased in different organs). Three key ingredients are combined to solve this challenging segmentation problem. First, marginal space learning (MSL) is applied to efficiently and effectively localize the multiple organs in the largely diverse CT volumes. Second, learning techniques, steerable features, are applied for robust boundary detection. This enables handling of highly heterogeneous texture pattern. Third, a novel information theoretic scheme is incorporated into the boundary inference process. The incorporation of the Jensen-Shannon divergence further drives the mesh to the best fit of the image, thus improves the segmentation performance. The proposed approach is tested on a challenging dataset containing 188 volumes from diverse sources. Our approach not only produces excellent segmentation accuracy, but also runs about eighty times faster than previous state-of-the-art solutions. The proposed method can be applied to CT images to provide visual guidance to physicians during the computer-aided diagnosis, treatment planning and image-guided radiotherapy to treat cancers in pelvic region. PMID:23286081

Lu, Chao; Zheng, Yefeng; Birkbeck, Neil; Zhang, Jingdan; Kohlberger, Timo; Tietjen, Christian; Boettger, Thomas; Duncan, James S; Zhou, S Kevin

2012-01-01

46

Automated segmentation and measurement of global white matter lesion volume in patients with multiple sclerosis.  

PubMed

A fully automated magnetic resonance (MR) segmentation method for identification and volume measurement of demyelinated white matter has been developed. Spin-echo MR brain scans were performed in 38 patients with multiple sclerosis (MS) and in 46 healthy subjects. Segmentation of normal tissues and white matter lesions (WML) was obtained, based on their relaxation rates and proton density maps. For WML identification, additional criteria included three-dimensional (3D) lesion shape and surrounding tissue composition. Segmented images were generated, and normal brain tissues and WML volumes were obtained. Sensitivity, specificity, and reproducibility of the method were calculated, using the WML identified by two neuroradiologists as the gold standard. The average volume of "abnormal" white matter in normal subjects (false positive) was 0.11 ml (range 0-0.59 ml). In MS patients the average WML volume was 31.0 ml (range 1.1-132.5 ml), with a sensitivity of 87.3%. In the reproducibility study, the mean SD of WML volumes was 2.9 ml. The procedure appears suitable for monitoring disease changes over time. J. Magn. Reson. Imaging 2000;12:799-807. PMID:11105017

Alfano, B; Brunetti, A; Larobina, M; Quarantelli, M; Tedeschi, E; Ciarmiello, A; Covelli, E M; Salvatore, M

2000-12-01

47

Topology Adaptive Deformable Surfaces for Medical Image Volume Segmentation  

Microsoft Academic Search

Deformable models, which include deformable con- tours (the popular snakes) and deformable surfaces, are a power- ful model-based medical image analysis technique. We develop a new class of deformable models by formulating deformable sur- faces in terms of an affine cell image decomposition (ACID). Our approach significantly extends standard deformable surfaces, while retaining their interactivity and other desirable properties. In

Tim Mcinerney; Demetri Terzopoulos

1999-01-01

48

Automatic large-volume object region segmentation in LiDAR point clouds  

NASA Astrophysics Data System (ADS)

LiDAR is a remote sensing method which produces precise point clouds consisting of millions of geo-spatially located 3D data points. Because of the nature of LiDAR point clouds, it can often be difficult for analysts to accurately and efficiently recognize and categorize objects. The goal of this paper is automatic large-volume object region segmentation in LiDAR point clouds. This efficient segmentation technique is intended to be a pre- processing step for the eventual classification of objects within the point cloud. The data is initially segmented into local histogram bins. This local histogram bin representation allows for the efficient consolidation of the point cloud data into voxels without the loss of location information. Additionally, by binning the points, important feature information can be extracted, such as the distribution of points, the density of points and a local ground. From these local histograms, a 3D automatic seeded region growing technique is applied. This technique performs seed selection based on two criteria, similarity and Euclidean distance to nearest neighbors. The neighbors of selected seeds are then examined and assigned labels based on location and Euclidean distance to a region mean. After the initial segmentation step, region integration is performed to rejoin over-segmented regions. The large amount of points in LiDAR data can make other segmentation techniques extremely time consuming. In addition to producing accurate object segmentation results, the proposed local histogram binning process allows for efficient segmentation, covering a point cloud of over 9,000 points in 10 seconds.

Varney, Nina M.; Asari, Vijayan K.

2014-10-01

49

Multi-stage learning for robust lung segmentation in challenging CT volumes.  

PubMed

Simple algorithms for segmenting healthy lung parenchyma in CT are unable to deal with high density tissue common in pulmonary diseases. To overcome this problem, we propose a multi-stage learning-based approach that combines anatomical information to predict an initialization of a statistical shape model of the lungs. The initialization first detects the carina of the trachea, and uses this to detect a set of automatically selected stable landmarks on regions near the lung (e.g., ribs, spine). These landmarks are used to align the shape model, which is then refined through boundary detection to obtain fine-grained segmentation. Robustness is obtained through hierarchical use of discriminative classifiers that are trained on a range of manually annotated data of diseased and healthy lungs. We demonstrate fast detection (35s per volume on average) and segmentation of 2 mm accuracy on challenging data. PMID:22003757

Sofka, Michal; Wetzl, Jens; Birkbeck, Neil; Zhang, Jingdan; Kohlberger, Timo; Kaftan, Jens; Declerck, Jérôme; Zhou, S Kevin

2011-01-01

50

Tracking as Segmentation of Spatial-Temporal Volumes by Anisotropic Weighted TV  

NASA Astrophysics Data System (ADS)

Tracking is usually interpreted as finding an object in single consecutive frames. Regularization is done by enforcing temporal smoothness of appearance, shape and motion. We propose a tracker, by interpreting the task of tracking as segmentation of a volume in 3D. Inherently temporal and spatial regularization is unified in a single regularization term. Segmentation is done by a variational approach using anisotropic weighted Total Variation (TV) regularization. The proposed convex energy is solved globally optimal by a fast primal-dual algorithm. Any image feature can be used in the segmentation cue of the proposed Mumford-Shah like data term. As a proof of concept we show experiments using a simple color-based appearance model. As demonstrated in the experiments, our tracking approach is able to handle large variations in shape and size, as well as partial and complete occlusions.

Unger, Markus; Mauthner, Thomas; Pock, Thomas; Bischof, Horst

51

A Theoretical Solution to MAP-EM Partial Volume Segmentation of Medical Images  

PubMed Central

Voxels near tissue borders in medical images contain useful clinical information, but are subject to severe partial volume (PV) effect, which is a major cause of imprecision in quantitative volumetric and texture analysis. When modeling each tissue type as a conditionally independent Gaussian distribution, the tissue mixture fractions in each voxel via the modeled unobservable random processes of the underlying tissue types can be estimated by maximum a posteriori expectation-maximization (MAP-EM) algorithm in an iterative manner. This paper presents, based on the assumption that PV effect could be fully described by a tissue mixture model, a theoretical solution to the MAP-EM segmentation algorithm, as opposed to our previous approximation which simplified the posteriori cost function as a quadratic term. It was found out that the theoretically-derived solution existed in a set of high-order non-linear equations. Despite of the induced computational complexity when seeking for optimum numerical solutions to non-linear equations, potential gains in robustness, consistency and quantitative precision were noticed. Results from both synthetic digital phantoms and real patient bladder magnetic resonance images were presented, demonstrating the accuracy and efficiency of the presented theoretical MAP-EM solution. PMID:19768123

Wang, Su; Lu, Hongyu; Liang, Zhengrong

2009-01-01

52

Analysis of Segmental Duplications and Genome Assembly in the Mouse  

PubMed Central

Limited comparative studies suggest that the human genome is particularly enriched for recent segmental duplications. The extent of segmental duplications in other mammalian genomes is unknown and confounded by methodological differences in genome assembly. Here, we present a detailed analysis of recent duplication content within the mouse genome using a whole-genome assembly comparison method and a novel assembly independent method, designed to take advantage of the reduced allelic variation of the C57BL/6J strain. We conservatively estimate that ?57% of all highly identical segmental duplications (?90%) were misassembled or collapsed within the working draft WGS assembly. The WGS approach often leaves duplications fragmented and unassigned to a chromosome when compared with the clone-ordered-based approach. Our preliminary analysis suggests that 1.7%–2.0% of the mouse genome is part of recent large segmental duplications (about half of what is observed for the human genome). We have constructed a mouse segmental duplication database to aid in the characterization of these regions and their integration into the final mouse genome assembly. This work suggests significant biological differences in the architecture of recent segmental duplications between human and mouse. In addition, our unique method provides the means for improving whole-genome shotgun sequence assembly of mouse and future mammalian genomes. PMID:15123579

Bailey, Jeffrey A.; Church, Deanna M.; Ventura, Mario; Rocchi, Mariano; Eichler, Evan E.

2004-01-01

53

Leaf image segmentation method based on multifractal detrended fluctuation analysis  

NASA Astrophysics Data System (ADS)

To identify singular regions of crop leaf affected by diseases, based on multifractal detrended fluctuation analysis (MF-DFA), an image segmentation method is proposed. In the proposed method, first, we defend a new texture descriptor: local generalized Hurst exponent, recorded as LHq based on MF-DFA. And then, box-counting dimension f(LHq) is calculated for sub-images constituted by the LHq of some pixels, which come from a specific region. Consequently, series of f(LHq) of the different regions can be obtained. Finally, the singular regions are segmented according to the corresponding f(LHq). Six kinds of corn diseases leaf's images are tested in our experiments. Both the proposed method and other two segmentation methods—multifractal spectrum based and fuzzy C-means clustering have been compared in the experiments. The comparison results demonstrate that the proposed method can recognize the lesion regions more effectively and provide more robust segmentations.

Wang, Fang; Li, Jin-Wei; Shi, Wen; Liao, Gui-Ping

2013-12-01

54

Sonar Picture Segmentation using Markovian Multigrid Algorithm and Multiresolution Analysis  

E-print Network

Sonar Picture Segmentation using Markovian Multigrid Algorithm and Multiresolution Analysis C on sonar pictures. On the sea-bottom lies some natural or man made objects that we have to detect (cf section 5) or the multiresolution analysis (cf section 6 ) we proposed on real sonar picture allow

55

Motion analysis and segmentation through spatio-temporal slices processing  

Microsoft Academic Search

This paper presents new approaches in characterizing and segmenting the content of video. These approaches are developed based upon the pattern analysis of spatio-temporal slices. While tradi- tional approaches to motion sequence analysis tend to formulate computational methodologies on two or three adjacent frames, spatio-temporal slices provide rich visual patterns along a larger temporal scale. In this paper, we first

Chong-Wah Ngo; Ting-Chuen Pong; Hong-Jiang Zhang

2003-01-01

56

Segmentation and Automated Social Hierarchy Detection through Email Network Analysis ?  

E-print Network

Segmentation and Automated Social Hierarchy Detection through Email Network Analysis ? German. Social Network, Enron, Behavior Pro#12;le, Link Mining, Data Mining, Corporate Householding. 1]. ? This work is based on an earlier work: Automated Social Hierarchy Detection through Email Network Analysis

Yang, Junfeng

57

Morphometric analysis of dermal collagen by color clusters segmentation.  

PubMed

Morphometric analysis of dermal collagen can provide quantitative support to dermatologic research. The authors of this article disclose a technique of digital image analysis which allows the identification of microscopic structures by color cluster segmentation regarding the estimate intensity and density of dermal collagen fibers. PMID:20676470

Miot, Hélio Amante; Brianezi, Gabrielli

2010-01-01

58

Efficient 3D volume segmentation of MR images by a modified deterministic annealing approach  

NASA Astrophysics Data System (ADS)

This paper presents the results of applying the deterministic annealing (DA) algorithm to simulated magnetic resonance image segmentation. The applicability of this methodology for 3-D segmentation has been rigorously tested by using the simulated MRI volumes of normal brain at the Brain Web [8] for the 181 slices and whole volume of different modalities (T1, T2, and PD) without and with various levels of noise and intensity inhomogeneities. With proper thresholding of the clusters formed by the modified DA almost zero misclassification was achieved without the presence of noise. Even up to 7% addition of noise and 40% inhomogeneity, the average misclassification rates of the voxels belonging to white matter, gray matter, and cerebrospinal fluid were found to be less than 5% after median filtering. The accuracy, stability, global optimization and speed of the DA algorithm for 3-D MR image segmentation could provide a more rigorous tool for identification of diseased brain tissues from 3-D MR images than other existing 3-D segmentation techniques. Further inquiry into the DA algorithm shows that it is a Bayesian classifier with the assumption that the data to be classified follow a multivariate normal distribution. The characteristic of being a Bayesian classifier guarantees its achievement of global optimization.

Ge, Zhanyu; Mitra, Sunanda

2001-07-01

59

Automated PET-guided liver segmentation from low-contrast CT volumes using probabilistic atlas.  

PubMed

The use of the functional PET information from PET-CT scans to improve liver segmentation from low-contrast CT data is yet to be fully explored. In this paper, we fully utilize PET information to tackle challenging liver segmentation issues including (1) the separation and removal of the surrounding muscles from liver region of interest (ROI), (2) better localization and mapping of the probabilistic atlas onto the low-contrast CT for a more accurate tissue classification, and (3) an improved initial estimation of the liver ROI to speed up the convergence of the expectation-maximization (EM) algorithm for the Gaussian distribution mixture model under the guidance of a probabilistic atlas. The primary liver extraction from the PET volume provides a simple mechanism to avoid the complicated pre-processing of feature extraction as used in the existing liver CT segmentation methods. It is able to guide the probabilistic atlas to better conform to the CT liver region and hence helps to overcome the challenge posed by liver shape variability. Our proposed method was evaluated against manual segmentation by experienced radiologists. Experimental results on 35 clinical PET-CT studies demonstrated that our method is accurate and robust in automated normal liver segmentation. PMID:21855163

Li, Changyang; Wang, Xiuying; Xia, Yong; Eberl, Stefan; Yin, Yong; Feng, David Dagan

2012-08-01

60

Segmental hair analysis and estimation of methamphetamine use pattern.  

PubMed

The aim of this study was to investigate whether the results of segmental hair analysis can be used to estimate patterns of methamphetamine (MA) use. Segmental hair analysis for MA and amphetamine (AP) was performed. Hair was cut into the hair root, consecutive 1 cm length segments and 1-4 cm length segments. Whole hair was also analyzed. The hair samples were incubated for 20 h in 1 mL methanol containing 1 % hydrochloric acid after washing the hair samples. Hair extracts were evaporated and derivatization was performed using trifluoroacetic anhydride in ethylacetate at 65 °C for 30 min. Derivatized extract was analyzed by gas chromatography/mass spectrometry. The 15 subjects consisted of 13 males and two females and their ages ranged from 25 to 42 (mean, 32). MA and AP concentrations in the whole hair ranged from 3.00 to 105.10 ng/mg (mean, 34.53) and from 0.05 to 4.76 ng/mg (mean, 2.42), respectively. Based on the analysis of the 1 cm length segmental hair, the results were interpreted in a way to distinguish between continuous use of MA (n?=?10), no recent but previous use of MA (n?=?3), and recent but no previous use of MA (n?=?2). Furthermore, the individuals were interpreted as light, moderate, and heavy users based on concentration ranges previously published. PMID:22955559

Han, Eunyoung; Yang, Heejin; Seol, Ilung; Park, Yunshin; Lee, Bongwoo; Song, Joon Myong

2013-03-01

61

Microscopy image segmentation tool: robust image data analysis.  

PubMed

We present a software package called Microscopy Image Segmentation Tool (MIST). MIST is designed for analysis of microscopy images which contain large collections of small regions of interest (ROIs). Originally developed for analysis of porous anodic alumina scanning electron images, MIST capabilities have been expanded to allow use in a large variety of problems including analysis of biological tissue, inorganic and organic film grain structure, as well as nano- and meso-scopic structures. MIST provides a robust segmentation algorithm for the ROIs, includes many useful analysis capabilities, and is highly flexible allowing incorporation of specialized user developed analysis. We describe the unique advantages MIST has over existing analysis software. In addition, we present a number of diverse applications to scanning electron microscopy, atomic force microscopy, magnetic force microscopy, scanning tunneling microscopy, and fluorescent confocal laser scanning microscopy. PMID:24689586

Valmianski, Ilya; Monton, Carlos; Schuller, Ivan K

2014-03-01

62

Microscopy image segmentation tool: Robust image data analysis  

SciTech Connect

We present a software package called Microscopy Image Segmentation Tool (MIST). MIST is designed for analysis of microscopy images which contain large collections of small regions of interest (ROIs). Originally developed for analysis of porous anodic alumina scanning electron images, MIST capabilities have been expanded to allow use in a large variety of problems including analysis of biological tissue, inorganic and organic film grain structure, as well as nano- and meso-scopic structures. MIST provides a robust segmentation algorithm for the ROIs, includes many useful analysis capabilities, and is highly flexible allowing incorporation of specialized user developed analysis. We describe the unique advantages MIST has over existing analysis software. In addition, we present a number of diverse applications to scanning electron microscopy, atomic force microscopy, magnetic force microscopy, scanning tunneling microscopy, and fluorescent confocal laser scanning microscopy.

Valmianski, Ilya, E-mail: ivalmian@ucsd.edu; Monton, Carlos; Schuller, Ivan K. [Department of Physics and Center for Advanced Nanoscience, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States)] [Department of Physics and Center for Advanced Nanoscience, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States)

2014-03-15

63

A Discussion on the Evaluation of A New Automatic Liver Volume Segmentation Method for Specified CT Image Datasets  

Microsoft Academic Search

This paper presents discussions on experimental result eval- uation outcomes of a new liver volume segmentation method developed for 10 specified CT image datasets. Precise liver surface segmentation is the first step and one of the major tasks in individual surgical resection virtual reality simulations. There are five major difficulties: Firstly, the automatic initialization of liver detection is often unreliable.

Ying Chi; Peter M M Cashman; Fernando Bello; Richard I Kitney

2007-01-01

64

Analysis of self-sustained oscillation sources in segmented flows  

Microsoft Academic Search

The analysis of self-sustained oscillations in segmented flow generated through porous walls has been carried out over a wide range of velocity levels; in fact, we studied a cold gas flow induced by injection through different wall injecting blocks. We have attempted in this study to analyse the potential unstable development occurring in solid propellant rocket motors. We lay emphasis

J. Vetel; F. Plourde; S. Doan-Kim

2002-01-01

65

Hyperspectral image segmentation, deblurring, and spectral analysis for material identification  

E-print Network

Hyperspectral image segmentation, deblurring, and spectral analysis for material identification-spectral or hyperspectral imagery is generally low resolution, it is possible for pixels in the image to contain several are then tested and compared on hyperspectral images associated with space object material identification

Plemmons, Robert J.

66

A Boosted Segmentation Method for Surgical Workflow Analysis  

E-print Network

. Furthermore, systems dedicated to the training and the evaluation of the surgical staff may also benefit from International Conference on Medical Image Computing and Computer Assisted Intervention - MICCAI 2007 4791 (2007A Boosted Segmentation Method for Surgical Workflow Analysis N. Padoy1,2 , T. Blum1 , I. Essa3 , H

Paris-Sud XI, Université de

67

A novel colonic polyp volume segmentation method for computer tomographic colonography  

NASA Astrophysics Data System (ADS)

Colorectal cancer is the third most common type of cancer. However, this disease can be prevented by detection and removal of precursor adenomatous polyps after the diagnosis given by experts on computer tomographic colonography (CTC). During CTC diagnosis, the radiologist looks for colon polyps and measures not only the size but also the malignancy. It is a common sense that to segment polyp volumes from their complicated growing environment is of much significance for accomplishing the CTC based early diagnosis task. Previously, the polyp volumes are mainly given from the manually or semi-automatically drawing by the radiologists. As a result, some deviations cannot be avoided since the polyps are usually small (6~9mm) and the radiologists' experience and knowledge are varying from one to another. In order to achieve automatic polyp segmentation carried out by the machine, we proposed a new method based on the colon decomposition strategy. We evaluated our algorithm on both phantom and patient data. Experimental results demonstrate our approach is capable of segment the small polyps from their complicated growing background.

Wang, Huafeng; Li, Lihong C.; Han, Hao; Song, Bowen; Peng, Hao; Wang, Yunhong; Wang, Lihua; Liang, Zhengrong

2014-03-01

68

Fast, accurate, and reproducible automatic segmentation of the brain in T1-weighted volume MRI data.  

PubMed

A new fast automated algorithm has been developed to segment the brain from T1-weighted volume MR images. The algorithm uses automated thresholding and morphological operations. It is fully three-dimensional and therefore independent of scan orientation. The validity and the performance of the algorithm were evaluated by comparing the automatically calculated brain volume with semi-automated measurements in 10 subjects, by calculating the brain volume from repeated scans in another 10 subjects, and by visual inspection. The mean and standard deviation of the difference between semi-automated and automated measurements were 0.56% and 2.8% of the mean brain volume, respectively, which is within inter-observer variability of the semi-automated method. The mean and standard deviation of the difference between the total volumes calculated from repeated scans were 0.40% and 1.2% of the mean brain volume, respectively. Good results were also obtained from a scan of abnormal brains. PMID:10398958

Lemieux, L; Hagemann, G; Krakow, K; Woermann, F G

1999-07-01

69

Analysis of segmented human body scans  

Microsoft Academic Search

Analysis on a dataset of 3D scanned surfaces have presented prob- lems because of incompleteness on the surfaces and because of variances in shape, size and pose. In this paper, a high-resolution generic model is aligned to data in the Civilian American and Eu- ropean Surface Anthropometry Resources (CAESAR) database in order to obtain a consistent parameterization. A Radial Basis

Pengcheng Xi; Won-sook Lee; Chang Shu

2007-01-01

70

Fully automated liver segmentation for low- and high- contrast CT volumes based on probabilistic atlases  

Microsoft Academic Search

Automated liver segmentation is problematic due to variations in liver shape \\/ size and because the liver has a similar density distribution to surrounding structures. We propose a method that: 1) utilizes iteratively constructed probabilistic liver and rib cage atlases, 2) conducts the Gaussian distribution analysis to avoid incorrectly classifying the irrelevant surrounding tissues as `liver region' in the conventional

ChangYang Li; Xiuying Wang; Stefan Eberl; Michael J. Fulham; Yong Yin; David Dagan Feng

2010-01-01

71

Ionogram analysis using fuzzy segmentation and connectedness techniques  

Microsoft Academic Search

We present a new procedure for the analysis of ionograms that evolves from methods developed for image analysis and utilizes techniques based on the concepts of fuzzy segmentation and connectedness. Ionogram traces are often not ``crisply'' defined, and we demonstrate that it is possible to approximate them as fuzzy subsets within the two-dimensional space defined by the time-of-flight and the

Lung-Chih Tsai; Frank T. Berkey

2000-01-01

72

Swept Volume Parameterization for Isogeometric Analysis  

E-print Network

Swept Volume Parameterization for Isogeometric Analysis M. Aignera , C. Heinrichb , B. J for generating NURBS parameteriza- tions of swept volumes. The class of these volumes covers a number of the generated NURBS volume parameterizations. In particular we dis- cuss the influence of the chosen

Jüttler, Bert

73

An interactive system for volume segmentation in computer-assisted surgery  

NASA Astrophysics Data System (ADS)

Computer-assisted surgery aims at a decreased surgical risk and a reduced recovery time of patients. However, its use is still limited to complex cases because of the high effort. It is often caused by the extensive medical image analysis. Especially, image segmentation requires a lot of manual work. Surgeons and radiologists are suffering from usability problems of many workstations. In this work, we present a dedicated workplace for interactive segmentation integratd within the CHILI (tele-)radiology system. The software comes with a lot of improvements with respect to its graphical user interface, the segmentation process and the segmentatin methods. We point out important software requirements and give insight into the concepts which were implemented. Further examples and applications illustrate the software system.

Kunert, Tobias; Heimann, Tobias; Schroter, Andre; Schobinger, Max; Bottger, Thomas; Thorn, Matthias; Wolf, Ivo; Engelmann, Uwe; Meinzer, Hans-Peter

2004-05-01

74

Documented Safety Analysis for the B695 Segment  

SciTech Connect

This Documented Safety Analysis (DSA) was prepared for the Lawrence Livermore National Laboratory (LLNL) Building 695 (B695) Segment of the Decontamination and Waste Treatment Facility (DWTF). The report provides comprehensive information on design and operations, including safety programs and safety structures, systems and components to address the potential process-related hazards, natural phenomena, and external hazards that can affect the public, facility workers, and the environment. Consideration is given to all modes of operation, including the potential for both equipment failure and human error. The facilities known collectively as the DWTF are used by LLNL's Radioactive and Hazardous Waste Management (RHWM) Division to store and treat regulated wastes generated at LLNL. RHWM generally processes low-level radioactive waste with no, or extremely low, concentrations of transuranics (e.g., much less than 100 nCi/g). Wastes processed often contain only depleted uranium and beta- and gamma-emitting nuclides, e.g., {sup 90}Sr, {sup 137}Cs, or {sup 3}H. The mission of the B695 Segment centers on container storage, lab-packing, repacking, overpacking, bulking, sampling, waste transfer, and waste treatment. The B695 Segment is used for storage of radioactive waste (including transuranic and low-level), hazardous, nonhazardous, mixed, and other waste. Storage of hazardous and mixed waste in B695 Segment facilities is in compliance with the Resource Conservation and Recovery Act (RCRA). LLNL is operated by the Lawrence Livermore National Security, LLC, for the Department of Energy (DOE). The B695 Segment is operated by the RHWM Division of LLNL. Many operations in the B695 Segment are performed under a Resource Conservation and Recovery Act (RCRA) operation plan, similar to commercial treatment operations with best demonstrated available technologies. The buildings of the B695 Segment were designed and built considering such operations, using proven building systems, and keeping them as simple as possible while complying with industry standards and institutional requirements. No operations to be performed in the B695 Segment or building system are considered to be complex. No anticipated future change in the facility mission is expected to impact the extent of safety analysis documented in this DSA.

Laycak, D

2008-09-11

75

MRI segmentation analysis in temporal lobe and idiopathic generalized epilepsy  

PubMed Central

Background Temporal lobe epilepsy (TLE) and idiopathic generalized epilepsy (IGE) patients have each been associated with extensive brain atrophy findings, yet to date there are no reports of head to head comparison of both patient groups. Our aim was to assess and compare between tissue-specific and structural brain atrophy findings in TLE to IGE patients and to healthy controls (HC). Methods TLE patients were classified in TLE lesional (L-TLE) or non-lesional (NL-TLE) based on presence or absence of MRI temporal structural abnormalities. High resolution 3 T MRI with automated segmentation by SIENAX and FIRST tools were performed in a group of patients with temporal lobe epilepsy (11 L-TLE and 15 NL-TLE) and in15 IGE as well as in 26 HC. Normal brain volume (NBV), normal grey matter volume (NGMV), normal white matter volume (NWMV), and volumes of subcortical deep grey matter structures were quantified. Using regression analyses, differences between the groups in both volume and left/right asymmetry were evaluated. Additionally, laterality of results was also evaluated to separately quantify ipsilateral and contralateral effects in the TLE group. Results All epilepsy groups had significantly lower NBV and NWMV compared to HC (p?volume than HC and IGE (p?=?0.001), and all epilepsy groups had significantly lower amygdala volume than HC (p?

2014-01-01

76

Automatic Segmentation and Quantitative Analysis of the Articular Cartilages From Magnetic Resonance Images of the Knee  

PubMed Central

In this paper, we present a segmentation scheme that automatically and accurately segments all the cartilages from magnetic resonance (MR) images of nonpathological knees. Our scheme involves the automatic segmentation of the bones using a three-dimensional active shape model, the extraction of the expected bone-cartilage interface (BCI), and cartilage segmentation from the BCI using a deformable model that utilizes localization, patient specific tissue estimation and a model of the thickness variation. The accuracy of this scheme was experimentally validated using leave one out experiments on a database of fat suppressed spoiled gradient recall MR images. The scheme was compared to three state of the art approaches, tissue classification, a modified semi-automatic watershed algorithm and nonrigid registration (B-spline based free form deformation). Our scheme obtained an average Dice similarity coefficient (DSC) of (0.83, 0.83, 0.85) for the (patellar, tibial, femoral) cartilages, while (0.82, 0.81, 0.86) was obtained with a tissue classifier and (0.73, 0.79, 0.76) was obtained with nonrigid registration. The average DSC obtained for all the cartilages using a semi-automatic watershed algorithm (0.90) was slightly higher than our approach (0.89), however unlike this approach we segment each cartilage as a separate object. The effectiveness of our approach for quantitative analysis was evaluated using volume and thickness measures with a median volume difference error of (5.92, 4.65, 5.69) and absolute Laplacian thickness difference of (0.13, 0.24, 0.12) mm. PMID:19520633

Fripp, Jurgen; Crozier, Stuart; Warfield, Simon K.; Ourselin, Sébastien

2010-01-01

77

4-D segmentation and normalization of 3He MR images for intrasubject assessment of ventilated lung volumes  

NASA Astrophysics Data System (ADS)

Although 3He MRI permits compelling visualization of the pulmonary air spaces, quantitation of absolute ventilation is difficult due to confounds such as field inhomogeneity and relative intensity differences between image acquisition; the latter complicating longitudinal investigations of ventilation variation with respiratory alterations. To address these potential difficulties, we present a 4-D segmentation and normalization approach for intra-subject quantitative analysis of lung hyperpolarized 3He MRI. After normalization, which combines bias correction and relative intensity scaling between longitudinal data, partitioning of the lung volume time series is performed by iterating between modeling of the combined intensity histogram as a Gaussian mixture model and modulating the spatial heterogeneity tissue class assignments through Markov random field modeling. Evaluation of the algorithm was retrospectively applied to a cohort of 10 asthmatics between 19-25 years old in which spirometry and 3He MR ventilation images were acquired both before and after respiratory exacerbation by a bronchoconstricting agent (methacholine). Acquisition was repeated under the same conditions from 7 to 467 days (mean +/- standard deviation: 185 +/- 37.2) later. Several techniques were evaluated for matching intensities between the pre and post-methacholine images with the 95th percentile value histogram matching demonstrating superior correlations with spirometry measures. Subsequent analysis evaluated segmentation parameters for assessing ventilation change in this cohort. Current findings also support previous research that areas of poor ventilation in response to bronchoconstriction are relatively consistent over time.

Contrella, Benjamin; Tustison, Nicholas J.; Altes, Talissa A.; Avants, Brian B.; Mugler, John P., III; de Lange, Eduard E.

2012-03-01

78

Chest-wall segmentation in automated 3D breast ultrasound images using thoracic volume classification  

NASA Astrophysics Data System (ADS)

Computer-aided detection (CAD) systems are expected to improve effectiveness and efficiency of radiologists in reading automated 3D breast ultrasound (ABUS) images. One challenging task on developing CAD is to reduce a large number of false positives. A large amount of false positives originate from acoustic shadowing caused by ribs. Therefore determining the location of the chestwall in ABUS is necessary in CAD systems to remove these false positives. Additionally it can be used as an anatomical landmark for inter- and intra-modal image registration. In this work, we extended our previous developed chestwall segmentation method that fits a cylinder to automated detected rib-surface points and we fit the cylinder model by minimizing a cost function which adopted a term of region cost computed from a thoracic volume classifier to improve segmentation accuracy. We examined the performance on a dataset of 52 images where our previous developed method fails. Using region-based cost, the average mean distance of the annotated points to the segmented chest wall decreased from 7.57±2.76 mm to 6.22±2.86 mm.art.

Tan, Tao; van Zelst, Jan; Zhang, Wei; Mann, Ritse M.; Platel, Bram; Karssemeijer, Nico

2014-03-01

79

Machine learning based vesselness measurement for coronary artery segmentation in cardiac CT volumes  

NASA Astrophysics Data System (ADS)

Automatic coronary centerline extraction and lumen segmentation facilitate the diagnosis of coronary artery disease (CAD), which is a leading cause of death in developed countries. Various coronary centerline extraction methods have been proposed and most of them are based on shortest path computation given one or two end points on the artery. The major variation of the shortest path based approaches is in the different vesselness measurements used for the path cost. An empirically designed measurement (e.g., the widely used Hessian vesselness) is by no means optimal in the use of image context information. In this paper, a machine learning based vesselness is proposed by exploiting the rich domain specific knowledge embedded in an expert-annotated dataset. For each voxel, we extract a set of geometric and image features. The probabilistic boosting tree (PBT) is then used to train a classifier, which assigns a high score to voxels inside the artery and a low score to those outside. The detection score can be treated as a vesselness measurement in the computation of the shortest path. Since the detection score measures the probability of a voxel to be inside the vessel lumen, it can also be used for the coronary lumen segmentation. To speed up the computation, we perform classification only for voxels around the heart surface, which is achieved by automatically segmenting the whole heart from the 3D volume in a preprocessing step. An efficient voxel-wise classification strategy is used to further improve the speed. Experiments demonstrate that the proposed learning based vesselness outperforms the conventional Hessian vesselness in both speed and accuracy. On average, it only takes approximately 2.3 seconds to process a large volume with a typical size of 512x512x200 voxels.

Zheng, Yefeng; Loziczonek, Maciej; Georgescu, Bogdan; Zhou, S. Kevin; Vega-Higuera, Fernando; Comaniciu, Dorin

2011-03-01

80

An analysis of segmentation dynamics throughout embryogenesis in the centipede Strigamia maritima  

PubMed Central

Background Most segmented animals add segments sequentially as the animal grows. In vertebrates, segment patterning depends on oscillations of gene expression coordinated as travelling waves in the posterior, unsegmented mesoderm. Recently, waves of segmentation gene expression have been clearly documented in insects. However, it remains unclear whether cyclic gene activity is widespread across arthropods, and possibly ancestral among segmented animals. Previous studies have suggested that a segmentation oscillator may exist in Strigamia, an arthropod only distantly related to insects, but further evidence is needed to document this. Results Using the genes even skipped and Delta as representative of genes involved in segment patterning in insects and in vertebrates, respectively, we have carried out a detailed analysis of the spatio-temporal dynamics of gene expression throughout the process of segment patterning in Strigamia. We show that a segmentation clock is involved in segment formation: most segments are generated by cycles of dynamic gene activity that generate a pattern of double segment periodicity, which is only later resolved to the definitive single segment pattern. However, not all segments are generated by this process. The most posterior segments are added individually from a localized sub-terminal area of the embryo, without prior pair-rule patterning. Conclusions Our data suggest that dynamic patterning of gene expression may be widespread among the arthropods, but that a single network of segmentation genes can generate either oscillatory behavior at pair-rule periodicity or direct single segment patterning, at different stages of embryogenesis. PMID:24289308

2013-01-01

81

Linear test bed. Volume 1: Test bed no. 1. [aerospike test bed with segmented combustor  

NASA Technical Reports Server (NTRS)

The Linear Test Bed program was to design, fabricate, and evaluation test an advanced aerospike test bed which employed the segmented combustor concept. The system is designated as a linear aerospike system and consists of a thrust chamber assembly, a power package, and a thrust frame. It was designed as an experimental system to demonstrate the feasibility of the linear aerospike-segmented combustor concept. The overall dimensions are 120 inches long by 120 inches wide by 96 inches in height. The propellants are liquid oxygen/liquid hydrogen. The system was designed to operate at 1200-psia chamber pressure, at a mixture ratio of 5.5. At the design conditions, the sea level thrust is 200,000 pounds. The complete program including concept selection, design, fabrication, component test, system test, supporting analysis and posttest hardware inspection is described.

1972-01-01

82

Human uterine lower segment myometrial cell and nuclear volume at term: influence of maternal age.  

PubMed

Little is known about the cytoarchitecture of human myometrial cells in pregnancy, and whether or not this may be influenced by maternal characteristics such as age, parity and body mass index (BMI). The aim of this study was primarily to evaluate human myometrial smooth muscle cell (SMC) and nuclear volume in the third trimester of human pregnancy, and secondarily to investigate if these parameters are altered in relation to the maternal characteristics outlined above. Myometrial biopsies were obtained from 30 women undergoing elective caesarean delivery at term. One-micrometer sections were prepared for light microscopy and 100-nm sections for electron microscopy. The nucleator technique was used to assess nuclear volume from the light microscopy images. Point-counting methodology was used on transmission electron micrographs to assess the percentage of the cell volume occupied by the nucleus. Cell volume was calculated from these measurements. The euchromatin to heterochromatin (Eu/Het) ratio was determined to ascertain whether differences in nuclear volume were due to an increased range of genes being transcribed. The mean (±?SEM) nuclear volume was 175?±?10??m(3) , the nucleus occupied 1.5?±?0.1% of the SMC and the mean cell size was 14?047?±?1352??m(3) . The Eu/Het ratio was 7.54?±?0.4. The mean volume of heterochromatin and euchromatin in the nucleus was 21.5?±?1.7 and 149?±?9??m(3) , respectively. A multivariate regression analysis revealed that advanced maternal age was associated with an increase in the percentage of the cell occupied by nucleus (R(2) ?=?0.32, P?=?0.004). There were no other significant effects of maternal age, BMI or parity on the measured parameters. These findings provide reliable volumes for human myometrial cells and their nuclei at term gestation, and show that nuclear volume fraction may be influenced by maternal age. PMID:25265023

Sweeney, Eva M; Dockery, Peter; Crankshaw, Denis J; O'Brien, Yvonne M; Walsh, Jennifer M; Morrison, John J

2014-12-01

83

Segmentation of the Manila subduction system from migrated multichannel seismics and wedge taper analysis  

NASA Astrophysics Data System (ADS)

Based on bathymetric data and multichannel seismic data, the Manila subduction system is divided into three segments, the North Luzon segment, the seamount chain segment and the West Luzon segment starts in Southwest Taiwan and runs as far as Mindoro. The volume variations of the accretionary prism, the forearc slope angle, taper angle variations support the segmentation of the Manila subduction system. The accretionary prism is composed of the outer wedge and the inner wedge separated by the slope break. The backstop structure and a 0.5-1 km thick subduction channel are interpreted in the seismic Line 973 located in the northeastern South China Sea. The clear décollement horizon reveals the oceanic sediment has been subducted beneath the accretionary prism. A number of splay faults occur in the active outer wedge. Taper angles vary from 8.0° ± 1° in the North Luzon segment, 9.9° ± 1° in the seamount segment to 11° ± 1° in the West Luzon segment. Based on variations between the taper angle and orthogonal convergence rates in the world continental margins and comparison between our results and the global compilation, different segments of the Manila subduction system fit well the global pattern. It suggests that subduction accretion dominates the north Luzon and seamount chain segment, but the steep slope indicates in the West Luzon segment and implies that tectonic erosion could dominate the West Luzon segment.

Zhu, Junjiang; Sun, Zongxun; Kopp, Heidrun; Qiu, Xuelin; Xu, Huilong; Li, Sanzhong; Zhan, Wenhuan

2013-12-01

84

Comparative assessment of statistical brain MR image segmentation algorithms and their impact on partial volume correction in PET  

Microsoft Academic Search

Magnetic resonance imaging (MRI)-guided partial volume effect correction (PVC) in brain positron emission tomography (PET) is now a well-established approach to compensate the large bias in the estimate of regional radioactivity concentration, especially for small structures. The accuracy of the algorithms developed so far is, however, largely dependent on the performance of segmentation methods partitioning MRI brain data into its

Habib Zaidi; Torsten Ruest; Frederic Schoenahl; Marie-Louise Montandon

2006-01-01

85

THE INTEGRATON OF GRAPH-BASED KNOWLEDGE DISCOVERY WITH IMAGE SEGMENTATION HIERARCHIES FOR DATA ANALYSIS,  

E-print Network

THE INTEGRATON OF GRAPH-BASED KNOWLEDGE DISCOVERY WITH IMAGE SEGMENTATION HIERARCHIES FOR DATA-based image analysis in which hierarchical image segmentations provided by the Recursive Hierarchical we discuss our initial approach to representing the RHSEG-produced hierarchical image segmentations

Cook, Diane J.

86

Study of tracking and data acquisition system for the 1990's. Volume 4: TDAS space segment architecture  

NASA Technical Reports Server (NTRS)

Tracking and data acquisition system (TDAS) requirements, TDAS architectural goals, enhanced TDAS subsystems, constellation and networking options, TDAS spacecraft options, crosslink implementation, baseline TDAS space segment architecture, and treat model development/security analysis are addressed.

Orr, R. S.

1984-01-01

87

Three-dimensional analysis tool for segmenting and measuring the structure of telomeres in mammalian nuclei  

NASA Astrophysics Data System (ADS)

Quantitative analysis in combination with fluorescence microscopy calls for innovative digital image measurement tools. We have developed a three-dimensional tool for segmenting and analyzing FISH stained telomeres in interphase nuclei. After deconvolution of the images, we segment the individual telomeres and measure a distribution parameter we call ?T. This parameter describes if the telomeres are distributed in a sphere-like volume (?T ~ 1) or in a disk-like volume (?T >> 1). Because of the statistical nature of this parameter, we have to correct for the fact that we do not have an infinite number of telomeres to calculate this parameter. In this study we show a way to do this correction. After sorting mouse lymphocytes and calculating ?T and using the correction introduced in this paper we show a significant difference between nuclei in G2 and nuclei in either G0/G1 or S phase. The mean values of ?T for G0/G1, S and G2 are 1.03, 1.02 and 13 respectively.

Vermolen, Bart J.; Young, Ian T.; Chuang, Alice; Wark, Landon; Chuang, Tony; Mai, Sabine; Garini, Yuval

2005-03-01

88

Range image segmentation through pattern analysis of multiscale difference information  

NASA Astrophysics Data System (ADS)

This work presents an image segmentation method for range data that uses multi-scale wavelet analysis in combination with statistical pattern recognition. We train a pattern- recognition system with scale-space data from the edge points of a training image. Once trained the system can determine the degree of edgeness of points in a new image. Before designing the segmentation system we set forth several goals. We desire that the system detect boundaries of small as well as large objects, be robust, and have few or no free parameters. Edges in an image respond to edge detectors at different scales; therefore combining edge detection information at multiple scales can create a more complete and robust edge detection. Scale-space refers to a family of derived signals where the fine-scale information is successively suppressed as scale increases. Edge points in images have a specific signature over scale space. We use a pattern recognition method to analyze these signatures as 1-D signals and therefore label edges in an image based on its multi-scale response to a wavelet transform. A fuzzy pattern classifier with one class determines the degree of membership in the edge class for each pixel in the image. Assigning this degree of membership to each pixel creates a fuzzy edge map. a watershed algorithm then creates a segmentation from this edge map. We use the wavelet transform to generate the scale space of a range image. We choose a spline wavelet used by Mallat. A simple, synthetic image with added noise and known edges provides a training set for the pattern recognition system. Known edge points from the image create a probability density function indicating membership in an edge class. The results from analyzing a complex real image are shown.

Burgiss, Samuel G., Jr.; Whitaker, Ross T.; Abidi, Mongi A.

1997-09-01

89

Image segmentation by iterative parallel region growing with application to data compression and image analysis  

NASA Technical Reports Server (NTRS)

Image segmentation can be a key step in data compression and image analysis. However, the segmentation results produced by most previous approaches to region growing are suspect because they depend on the order in which portions of the image are processed. An iterative parallel segmentation algorithm avoids this problem by performing globally best merges first. Such a segmentation approach, and two implementations of the approach on NASA's Massively Parallel Processor (MPP) are described. Application of the segmentation approach to data compression and image analysis is then described, and results of such application are given for a LANDSAT Thematic Mapper image.

Tilton, James C.

1988-01-01

90

Semi-automatic segmentation for 3D motion analysis of the tongue with dynamic MRI.  

PubMed

Dynamic MRI has been widely used to track the motion of the tongue and measure its internal deformation during speech and swallowing. Accurate segmentation of the tongue is a prerequisite step to define the target boundary and constrain the tracking to tissue points within the tongue. Segmentation of 2D slices or 3D volumes is challenging because of the large number of slices and time frames involved in the segmentation, as well as the incorporation of numerous local deformations that occur throughout the tongue during motion. In this paper, we propose a semi-automatic approach to segment 3D dynamic MRI of the tongue. The algorithm steps include seeding a few slices at one time frame, propagating seeds to the same slices at different time frames using deformable registration, and random walker segmentation based on these seed positions. This method was validated on the tongue of five normal subjects carrying out the same speech task with multi-slice 2D dynamic cine-MR images obtained at three orthogonal orientations and 26 time frames. The resulting semi-automatic segmentations of a total of 130 volumes showed an average dice similarity coefficient (DSC) score of 0.92 with less segmented volume variability between time frames than in manual segmentations. PMID:25155697

Lee, Junghoon; Woo, Jonghye; Xing, Fangxu; Murano, Emi Z; Stone, Maureen; Prince, Jerry L

2014-12-01

91

Influence of cold walls on PET image quantification and volume segmentation: A phantom study  

SciTech Connect

Purpose: Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These “cold” walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in errors in the estimation of standardized uptake values. Numerous papers suggest that this is an issue for phantom work simulating tumor tissue, quality control, and calibration work. This study aims to investigate the influence of the cold plastic wall thickness on the quantification of 18F-fluorodeoxyglucose on the image activity recovery and on the performance of advanced automatic segmentation algorithms for the delineation of active regions delimited by plastic walls.Methods: A commercial set of six spheres of different diameters was replicated using a manufacturing technique which achieves a reduction in plastic walls thickness of up to 90%, while keeping the same internal volume. Both sets of thin- and thick-wall inserts were imaged simultaneously in a custom phantom for six different tumor-to-background ratios. Intensity values were compared in terms of mean and maximum standardized uptake values (SUVs) in the spheres and mean SUV of the hottest 1 ml region (SUV{sub max}, SUV{sub mean}, and SUV{sub peak}). The recovery coefficient (RC) was also derived for each sphere. The results were compared against the values predicted by a theoretical model of the PET-intensity profiles for the same tumor-to-background ratios (TBRs), sphere sizes, and wall thicknesses. In addition, ten automatic segmentation methods, written in house, were applied to both thin- and thick-wall inserts. The contours obtained were compared to computed tomography derived gold standard (“ground truth”), using five different accuracy metrics.Results: The authors' results showed that thin-wall inserts achieved significantly higher SUV{sub mean}, SUV{sub max}, and RC values (up to 25%, 16%, and 25% higher, respectively) compared to thick-wall inserts, which was in agreement with the theory. This effect decreased with increasing sphere size and TBR, and resulted in substantial (>5%) differences between thin- and thick-wall inserts for spheres up to 30 mm diameter and TBR up to 4. Thinner plastic walls were also shown to significantly improve the delineation accuracy for the majority of the segmentation methods tested, by increasing the proportion of lesion voxels detected, although the errors in image quantification remained non-negligible.Conclusions: This study quantified the significant effect of a 90% reduction in the thickness of insert walls on SUV quantification and PET-based boundary detection. Mean SUVs inside the inserts and recovery coefficients were particularly affected by the presence of thick cold walls, as predicted by a theoretical approach. The accuracy of some delineation algorithms was also significantly improved by the introduction of thin wall inserts instead of thick wall inserts. This study demonstrates the risk of errors deriving from the use of cold wall inserts to assess and compare the performance of PET segmentation methods.

Berthon, B.; Marshall, C. [Wales Research and Diagnostic Positron Emission Tomography Imaging Centre, Cardiff CF14 4XN (United Kingdom)] [Wales Research and Diagnostic Positron Emission Tomography Imaging Centre, Cardiff CF14 4XN (United Kingdom); Edwards, A.; Spezi, E. [Department of Medical Physics, Velindre Cancer Centre, Cardiff CF14 2TL (United Kingdom)] [Department of Medical Physics, Velindre Cancer Centre, Cardiff CF14 2TL (United Kingdom); Evans, M. [Velindre Cancer Centre, Cardiff CF14 2TL (United Kingdom)] [Velindre Cancer Centre, Cardiff CF14 2TL (United Kingdom)

2013-08-15

92

An online segmentation tool for cervicographic image analysis  

Microsoft Academic Search

Cervicography is an important visual screening method for cervical cancer prevention. Automatic segmentation of clinically significant regions in acquired images may provide valuable assistance toward research in cervical cancer detection. This paper presents a Web-accessible cervicographic image segmentation system that incorporates several novel segmentation algorithms developed for particular tissue types and landmarks. The system combines the advantages of two commonly

Zhiyun Xue; Sameer Antani; L. Rodney Long; George R. Thoma

2010-01-01

93

Renal Perfusional Cortex Volume for Arterial Input Function Measured by Semiautomatic Segmentation Technique Using MDCT Angiographic Data With 0.5-mm Collimation.  

PubMed

OBJECTIVE. The purpose of this study was to evaluate the usefulness of renal perfusional cortex volume for arterial input function. MATERIALS AND METHODS. This retrospective study included 45 potential kidney donors-33 patients with aortic dissection and 12 patients with renovascular hypertension-who underwent both MDCT angiography with 0.5-mm collimation and renal (99m)Tc-diethylenetriamine pentaacetic acid (DTPA) scanning using the modified Gates method. Each perfusional cortex volume for the arterial input function and parenchymal volume was measured by semiautomatic segmentation using the region-growing technique. Linear regression analysis and correlation coefficients were used to assess the impact of the cortical volume, parenchymal volume, and renal scanning glomerular filtration rate (GFR) on estimated GFR (eGFR) using a modified Modification of Diet in Renal Disease (MDRD) equation. RESULTS. The correlation coefficient was higher for the total renal DTPA GFR adjusted for body surface area, weight-adjusted perfusion cortex volume, and adjusted total parenchyma volume in rank (r = 0.712, 0.642, 0.510, respectively, p< 0.0001 for each). The coefficient of the right renal perfusional cortex volume percent with a mean value of 52.1% ± 10.1% was 0.826 (p < 0.0001) for the right renal DTPA GFR percent with a mean value of 51.0% ± 12.1% (range, 22.0-89.5%), although the value for the right renal parenchymal volume percent with a mean value of 49.5% ± 5.5% was 0.764 (p < 0.0001). CONCLUSION. Weight-adjusted perfusional cortex volume for arterial input function can be measured clinically and may replace renal DTPA scanning using the modified Gates method. PMID:25539243

Torimoto, Izumi; Takebayashi, Shigeo; Sekikawa, Zenjiro; Teranishi, Junichi; Uchida, Keiji; Inoue, Tomio

2015-01-01

94

Effect of Volume and Temperature on the Global and Segmental Dynamics in Polypropylene Glycol and 1,4-polyisoprene  

E-print Network

Published dielectric relaxation measurements on polypropylene glycol and 1,4-polyisoprene are analyzed to determine the relative effect that thermal energy and volume have on the temperature dependence of the normal mode relaxation times, and compare this to their effect on the temperature dependence of the local segmental relaxation times. We find that for both polymers at temperatures well above Tg, both relaxation modes are governed more by thermal energy than by volume, although the latter's contribution is not negligible. Such a result is consistent with an assumption underlying models for polymer viscoelasticity, such as the Rouse and tube models, that the friction coefficient governing motions over large length scales can be identified with the local segmental friction coefficient. We also show that relaxation data for both the segmental and the normal mode superimpose, when expressed as a function of the product of the temperature and the volume, the latter raised to a power. This scaling form arises from an inverse power form for the intermolecular potential. The value of the exponent on the volume for these two polymers indicates a relatively "soft" potential.

C. M. Roland; R. Casalini; M. Paluch

2004-04-07

95

Blood vessel segmentation using line-direction vector based on Hessian analysis  

NASA Astrophysics Data System (ADS)

For decision of the treatment strategy, grading of stenoses is important in diagnosis of vascular disease such as arterial occlusive disease or thromboembolism. It is also important to understand the vasculature in minimally invasive surgery such as laparoscopic surgery or natural orifice translumenal endoscopic surgery. Precise segmentation and recognition of blood vessel regions are indispensable tasks in medical image processing systems. Previous methods utilize only ``lineness'' measure, which is computed by Hessian analysis. However, difference of the intensity values between a voxel of thin blood vessel and a voxel of surrounding tissue is generally decreased by the partial volume effect. Therefore, previous methods cannot extract thin blood vessel regions precisely. This paper describes a novel blood vessel segmentation method that can extract thin blood vessels with suppressing false positives. The proposed method utilizes not only lineness measure but also line-direction vector corresponding to the largest eigenvalue in Hessian analysis. By introducing line-direction information, it is possible to distinguish between a blood vessel voxel and a voxel having a low lineness measure caused by noise. In addition, we consider the scale of blood vessel. The proposed method can reduce false positives in some line-like tissues close to blood vessel regions by utilization of iterative region growing with scale information. The experimental result shows thin blood vessel (0.5 mm in diameter, almost same as voxel spacing) can be extracted finely by the proposed method.

Nimura, Yukitaka; Kitasaka, Takayuki; Mori, Kensaku

2010-03-01

96

Cluster analysis for automatic image segmentation in dynamic scintigraphies.  

PubMed

An original and entirely automatic algorithm is proposed to select regions of interest (ROIs) on dynamic scintigrams. This algorithm is based on factor analysis and on cluster analysis. It consists of first extracting the orthogonal factor images of the series using factor analysis of correspondence. These factor images are then automatically segmented in ROIs using a hierarchical ascendant classification procedure. The distance used for the classification is the 'minimum added intra-class variance' distance. This algorithm has been implemented on a fast computer dedicated to nuclear medicine (Nodecrest Micas V system). The time of calculation on 1000 pixels from 40 images is less than 5 min when three factor images are used. This algorithm is validated using a numerical phantom and is illustrated using renal (99Tcm DTPA) and cardiac (equilibrium gated angiography) dynamic scintigraphies. The results show that the algorithm is able to recognize the bladder, the renal cavities and the renal parenchyma on the renal series, and the ventricules and the atria on the cardiac series. PMID:2371018

Hannequin, P; Liehn, J C; Valeyre, J

1990-05-01

97

Segmentation and classification of capnograms: application in respiratory variability analysis.  

PubMed

Variability analysis of respiratory waveforms has been shown to provide key insights into respiratory physiology and has been used successfully to predict clinical outcomes. The current standard for quality assessment of the capnogram signal relies on a visual analysis performed by an expert in order to identify waveform artifacts. Automated processing of capnograms is desirable in order to extract clinically useful features over extended periods of time in a patient monitoring environment. However, the proper interpretation of capnogram derived features depends upon the quality of the underlying waveform. In addition, the comparison of capnogram datasets across studies requires a more practical approach than a visual analysis and selection of high-quality breath data. This paper describes a system that automatically extracts breath-by-breath features from capnograms and estimates the quality of individual breaths derived from them. Segmented capnogram breaths were presented to expert annotators, who labeled the individual physiological breaths into normal and multiple abnormal breath types. All abnormal breath types were aggregated into the abnormal class for the purpose of this manuscript, with respiratory variability analysis as the end-application. A database of 11,526 breaths from over 300 patients was created, comprising around 35% abnormal breaths. Several simple classifiers were trained through a stratified repeated ten-fold cross-validation and tested on an unseen portion of the labeled breath database, using a subset of 15 features derived from each breath curve. Decision Tree, K-Nearest Neighbors (KNN) and Naive Bayes classifiers were close in terms of performance (AUC of 90%, 89% and 88% respectively), while using 7, 4 and 5 breath features, respectively. When compared to airflow derived timings, the 95% confidence interval on the mean difference in interbreath intervals was ± 0.18 s. This breath classification system provides a fast and robust pre-processing of continuous respiratory waveforms, thereby ensuring reliable variability analysis of breath-by-breath parameter time series. PMID:25389703

Herry, C L; Townsend, D; Green, G C; Bravi, A; Seely, A J E

2014-12-01

98

Superpixel segmentation for analysis of hyperspectral data sets, with application to Compact Reconnaissance Imaging  

E-print Network

segmentation for analysis of hyperspectral data sets, with application to Compact Reconnaissance ImagingSuperpixel segmentation for analysis of hyperspectral data sets, with application to Compact Reconnaissance Imaging Spectrometer for Mars data, Moon Mineralogy Mapper data, and Ariadnes Chaos, Mars Martha S

Royer, Dana

99

Extracellular and intracellular volume variations during postural change measured by segmental and wrist-ankle bioimpedance spectroscopy  

Microsoft Academic Search

Extracellular (ECW) and intracellular (ICW) volumes were measured using both segmental and wrist-ankle (W-A) bioimpedance spectroscopy (5-1000 kHz) in 15 healthy subjects (7 men, 8 women). In the 1st protocol, the subject, after sitting for 30 min, laid supine for at least 30 min. In the second protocol, the subject, who had been supine for 1 hr, sat up in

Marianne Fenech; Michel Y. Jaffrin

2004-01-01

100

3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head  

NASA Astrophysics Data System (ADS)

Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

2010-03-01

101

Evaluation of a Novel Approach for Automatic Volume Determination of Glioblastomas Based on Several Manual Expert Segmentations  

E-print Network

The glioblastoma multiforme is the most common malignant primary brain tumor and is one of the highest malignant human neoplasms. During the course of disease, the evaluation of tumor volume is an essential part of the clinical follow-up. However, manual segmentation for acquisition of tumor volume is a time-consuming process. In this paper, a new approach for the automatic segmentation and volume determination of glioblastomas (glioblastoma multiforme) is presented and evaluated. The approach uses a user-defined seed point inside the glioma to set up a directed 3D graph. The nodes of the graph are obtained by sampling along rays that are sent through the surface points of a polyhedron. After the graph has been constructed, the minimal s-t cut is calculated to separate the glioblastoma from the background. For evaluation, 12 Magnetic Resonance Imaging (MRI) data sets were manually segmented slice by slice, by neurosurgeons with several years of experience in the resection of gliomas. Afterwards, the manual se...

Egger, Jan; Kuhnt, Daniela; Carl, Barbara; Kappus, Christoph; Freisleben, Bernd; Nimsky, Christopher

2011-01-01

102

Analysis of segmental phosphate absorption in intact rats. A compartmental analysis approach.  

PubMed

Available information supports the dominance of the proximal intestine in inorganic phosphate (Pi) absorption. However, there is no strategy for analyzing segmental Pi absorption from a spontaneously propelled meal in an intact animal. We propose a solution using compartmental analysis. After intragastric administration of a 32P-labeled Pi liquid meal containing a nonabsorbable marker, [14C]polyethylene glycol (PEG), rats were killed at 2, 10, 20, 30, 60, 120, and 240 min. The gastrointestinal tract was removed and divided into seven segments, from which 32P and [14C]PEG were recovered. Data was expressed as a percentage of the dose fed, i.e., (32P[in segment] divided by 32P[fed]) and [14C]PEG[in segment] divided by [14C]PEG[fed]), respectively. A compartmental model was constructed and the rate constants for intersegmental transit and segmental absorption were estimated. The "goodness of fit" between the simulated model and the actual data indicates the estimated rate constants reflect in vivo events. The duodenum, with the highest transit and absorption rates, accounted for a third of the total absorption. However, the terminal ileum, with a lower absorption rate but a longer transit time, absorbed an equal amount of Pi. This approach allows the analysis of the mechanism and the regulation of Pi absorption under more authentic in vivo conditions. PMID:8450069

Kayne, L H; D'Argenio, D Z; Meyer, J H; Hu, M S; Jamgotchian, N; Lee, D B

1993-03-01

103

Recurrence interval analysis of trading volumes  

NASA Astrophysics Data System (ADS)

We study the statistical properties of the recurrence intervals ? between successive trading volumes exceeding a certain threshold q . The recurrence interval analysis is carried out for the 20 liquid Chinese stocks covering a period from January 2000 to May 2009, and two Chinese indices from January 2003 to April 2009. Similar to the recurrence interval distribution of the price returns, the tail of the recurrence interval distribution of the trading volumes follows a power-law scaling, and the results are verified by the goodness-of-fit tests using the Kolmogorov-Smirnov (KS) statistic, the weighted KS statistic and the Cramér-von Mises criterion. The measurements of the conditional probability distribution and the detrended fluctuation function show that both short-term and long-term memory effects exist in the recurrence intervals between trading volumes. We further study the relationship between trading volumes and price returns based on the recurrence interval analysis method. It is found that large trading volumes are more likely to occur following large price returns, and the comovement between trading volumes and price returns is more pronounced for large trading volumes.

Ren, Fei; Zhou, Wei-Xing

2010-06-01

104

Video Segmentation with the Assistance of Audio Content Analysis  

Microsoft Academic Search

Video structure extraction is essential to automatic content-based organization, retrieval and browsing of video. However, while many robust shot segmentation algorithms have been developed, it is still difficult to extract scene structures or group shots into scenes. In this paper, we present a novel audio assisted video segmentation scheme, in which audio and color information is integrated in video scene

Hao Jiang; Tong Lin; Hong-Jiang Zhang

2000-01-01

105

Robust analysis of feature spaces: color image segmentation  

Microsoft Academic Search

A general technique for the recovery of significant im- age features is presented. The technique is based on the mean shift algorithm, a simple nonparametric procedure for estimating density gradients. Drawbacks of the current methods (including robust clustering) are avoided. Feature space of any nature can be processed, and as an example, color image segmentation is discussed. The segmentation is

Dorin Comaniciu; Peter Meer

1997-01-01

106

Analysis of image thresholding segmentation algorithms based on swarm intelligence  

NASA Astrophysics Data System (ADS)

Swarm intelligence-based image thresholding segmentation algorithms are playing an important role in the research field of image segmentation. In this paper, we briefly introduce the theories of four existing image segmentation algorithms based on swarm intelligence including fish swarm algorithm, artificial bee colony, bacteria foraging algorithm and particle swarm optimization. Then some image benchmarks are tested in order to show the differences of the segmentation accuracy, time consumption, convergence and robustness for Salt & Pepper noise and Gaussian noise of these four algorithms. Through these comparisons, this paper gives qualitative analyses for the performance variance of the four algorithms. The conclusions in this paper would give a significant guide for the actual image segmentation.

Zhang, Yi; Lu, Kai; Gao, Yinghui; Yang, Bo

2013-03-01

107

Evaluation of atlas based auto-segmentation for head and neck target volume delineation in adaptive/replan IMRT  

NASA Astrophysics Data System (ADS)

IMRT for head and neck patients requires clinicians to delineate clinical target volumes (CTV) on a planning-CT (>2hrs/patient). When patients require a replan-CT, CTVs must be re-delineated. This work assesses the performance of atlas-based autosegmentation (ABAS), which uses deformable image registration between planning and replan-CTs to auto-segment CTVs on the replan-CT, based on the planning contours. Fifteen patients with planning-CT and replan-CTs were selected. One clinician delineated CTVs on the planning-CTs and up to three clinicians delineated CTVs on the replan-CTs. Replan-CT volumes were auto-segmented using ABAS using the manual CTVs from the planning-CT as an atlas. ABAS CTVs were edited manually to make them clinically acceptable. Clinicians were timed to estimate savings using ABAS. CTVs were compared using dice similarity coefficient (DSC) and mean distance to agreement (MDA). Mean inter-observer variability (DSC>0.79 and MDA<2.1mm) was found to be greater than intra-observer variability (DSC>0.91 and MDA<1.5mm). Comparing ABAS to manual CTVs gave DSC=0.86 and MDA=2.07mm. Once edited, ABAS volumes agreed more closely with the manual CTVs (DSC=0.87 and MDA=1.87mm). The mean clinician time required to produce CTVs reduced from 169min to 57min when using ABAS. ABAS segments volumes with accuracy close to inter-observer variability however the volumes require some editing before clinical use. Using ABAS reduces contouring time by a factor of three.

Speight, R.; Karakaya, E.; Prestwich, R.; Sen, M.; Lindsay, R.; Harding, R.; Sykes, J.

2014-03-01

108

A level set segmentation for computer-aided dental x-ray analysis  

NASA Astrophysics Data System (ADS)

A level-set-based segmentation framework for Computer Aided Dental X-rays Analysis (CADXA) is proposed. In this framework, we first employ level set methods to segment the dental X-ray image into three regions: Normal Region (NR), Potential Abnormal Region (PAR), Abnormal and Background Region (ABR). The segmentation results are then used to build uncertainty maps based on a proposed uncertainty measurement method and an analysis scheme is applied. The level set segmentation method consists of two stages: a training stage and a segmentation stage. During the training stage, manually chosen representative images are segmented using hierarchical level set region detection. The segmentation results are used to train a support vector machine (SVM) classifier. During the segmentation stage, a dental X-ray image is first classified by the trained SVM. The classifier provides an initial contour which is close to the correct boundary for the coupled level set method which is then used to further segment the image. Different dental X-ray images are used to test the framework. Experimental results show that the proposed framework achieves faster level set segmentation and provides more detailed information and indications of possible problems to the dentist. To our best knowledge, this is one of the first results on CADXA using level set methods.

Li, Shuo; Fevens, Thomas; Krzyzak, Adam; Li, Song

2005-04-01

109

Multivision determination of the volume of human body segments and implementation of a dynamic model  

Microsoft Academic Search

Many biomechanical models analyzing human movements require the morphological data of each body segment, such as partial mass inertial characteristics. These data may be evaluated from the three-dimensional (3-D) envelope of these segments. This study was aimed at developing a simple system compatible with routine procedures with which these 3-D envelopes could be measured. Testing was carried out with an

J. Y Ertaud; X Savatier; W Schmidt; J. M Thomine; F. H Dujardin

1999-01-01

110

An automatic variational level set segmentation framework for computer aided dental X-rays analysis in clinical environments  

Microsoft Academic Search

An automatic variational level set segmentation framework for Computer Aided Dental X-rays Analysis (CADXA) in clinical environments is proposed. Designed for clinical environments, the segmentation contains two stages: a training stage and a segmentation stage. During the training stage, first, manually chosen representative images are segmented using hierarchical level set region detection. Then the window based feature extraction followed by

Shuo Li; Thomas Fevens; Adam Krzyzak; Song Li

2006-01-01

111

An Integrated Segmentation and Classification Approach Applied to Multiple Sclerosis Analysis  

E-print Network

1 An Integrated Segmentation and Classification Approach Applied to Multiple Sclerosis Analysis utility in detecting Multiple Sclerosis lesions in 3D multi-channel MRI data. Our method uses segmentation structures focusing on 3D MRI brain data containing scans of Multiple Sclerosis (MS) patients. Manual

112

An Integrated Segmentation and Classification Approach Applied to Multiple Sclerosis Analysis  

E-print Network

An Integrated Segmentation and Classification Approach Applied to Multiple Sclerosis Analysis, and demonstrate its utility in detecting multiple sclerosis lesions in 3D MRI data. Our method uses segmentation structures focusing on 3D MRI brain data containing scans of multiple sclerosis (MS) patients. Research

113

Multi-resolution Segmentation and Shape Analysis for Remote Sensing Image Classification  

E-print Network

, agricultural and ecological studies. The usual choice for the level of processing image data has been pixel delineation of agricultural fields [9]. We model spatial information by segmenting images into spatiallyMulti-resolution Segmentation and Shape Analysis for Remote Sensing Image Classification Selim

Aksoy, Selim

114

Analysis of multichannel narrow-band filters for image texture segmentation  

Microsoft Academic Search

A model for texture analysis and segmentation using multiple oriented channel filters is analyzed in the general framework. Several different arguments are applied leading to the conclusion that the two-dimensional Gabor filters possess strong optimality properties for this task. Properties of the multiple-channel segmentation approach are analyzed. In particular, perturbations of textures from an ideal model are found to have

Alan C. Bovik

1991-01-01

115

A New Approach to Automated Retinal Vessel Segmentation Using Multiscale Analysis  

Microsoft Academic Search

Computer based analysis for automated segmentation of blood vessels in retinal images will help eye care specialists screen larger populations for vessel abnormalities. However, automated retinal segmentation is complicated by the fact that the width of retinal vessels can vary from very large to very small, and that the local contrast of vessels is unstable, especially in unhealthy ocular fundus.

Qin Li; Jane You; Lei Zhang; David Zhang; Prabir Bhattacharya

2009-01-01

116

A New Approach to Automated Retinal Vessel Segmentation Using Multiscale Analysis  

Microsoft Academic Search

Abstract Computer based analysis for automated segmentation of blood vessels in retinal images will help eye care specialists screen larger populations for vessel abnormalities. However, automated retinal segmentation is complicated by the fact that the width of retinal vessels can vary from ,very large to very small, and that the local contrast of vessels is unstable, especially in unhealthy ocular

Qin Li; Lei Zhang; David Zhang; Prabir Bhattacharya

2006-01-01

117

Analytic diffraction analysis of a 32-m telescope with hexagonal segments for high-contrast imaging  

NASA Astrophysics Data System (ADS)

Large segmented telescopes cannot be modeled accurately with fast-Fourier-transform techniques since small features such as gaps between the segments will be inadequately sampled. An analytic Fourier-transform method can be used to model any pupil configuration with straight edges, including tolerance analysis and some types of apodization. We analytically investigated a 32-m segmented primary with 18 hexagonal segments for high-contrast imaging. There are significant regions in the image in which extrasolar planets could be detected. However, the hexagonal profile of the pupil was not as useful as expected. The gaps between the segments, the secondary obscuration, and the secondary spiders must be as small as possible and their edges must be apodized. Apodizing the edges of the individual segments reduced the useful regions in the image since the gaps appeared to be wider.

Sabatke, Erin; Burge, James; Sabatke, Derek

2005-03-01

118

Molecular cytogenetic analysis of supernumerary heterochromatic segments in Rumex acetosa.  

PubMed

The dioecious plant Rumex acetosa shows intraspecific karyotype variation, caused by supernumerary heterochromatic segments or DAPI (4',6-diamidino-2 phenylindole)-bands at the ends of the short arms of three pairs of autosomes. A DNA sequence (RAE730) specific to the supernumerary heterochromatic segments was cloned and sequenced. RAE730 was about 730 bp and AT-rich (71% AT-content). Using fluorescence in situ hybridization (FISH), RAE730 was localized in the supernumerary DAPI-positive heterochromatic segments on several mitotic chromosomes and chromocenters in interphase nuclei, but not in the DAPI-bands of Y or B chromosomes. RAE730 was tandemly arranged in the genome, and the copy number varied between plants from 40000 to 304000 copies per 2C, corresponding to the relative amount of supernumerary heterochromatic segments per genome. These results indicate that the karyotype variation caused by the supernumerary heterochromatic segment was generated by amplification or reduction of the tandem repeats of RAE730. PMID:10791829

Shibata, F; Hizume, M; Kuroki, Y

2000-04-01

119

Segmentation of aortic flow in real-time spiral phase-contrast MRI for assessment of stroke volume variability Gustavo Maia Queiroz Mendona1  

E-print Network

Segmentation of aortic flow in real-time spiral phase-contrast MRI for assessment of stroke volume variability Gustavo Maia Queiroz Mendonça1 and Joao L. A. Carvalho1 1 Department of Electrical Engineering capable of non-invasively measuring the stroke volume associated with each individual heartbeat1

Carvalho, João Luiz

120

Tie-Zone Watershed, Bottlenecks, and Segmentation Robustness Analysis  

Microsoft Academic Search

In a recent paper (1), a new type of watershed (WS) transform was introduced: the tie-zone watershed (TZWS). This region-based watershed transform does not depend on arbitrary implementation and provides a unique (and thereby unbiased) optimal solution. Indeed, many optimal solutions are sometimes possible when segmenting an im- age by WS. The TZWS assigns each pixel to a catchment basin

Romaric Audigier; Roberto De Alencar Lotufo

2005-01-01

121

Applications of Recursive Segmentation to the Analysis of DNA Sequences  

Microsoft Academic Search

Recursive segmentation is a procedure that partitions a DNA sequence into domains with a homogeneous composition of the four nucleotides A, C, G and T. This procedure can also be applied to any sequence converted from a DNA sequence, such as to a binary strong(G + C)\\/weak(A+ T) sequence, to a binary sequence indicating the presence or absence of the

Wentian Li; Pedro Bernaola-galván; Fatameh Haghighi; Ivo Grosse

2002-01-01

122

Automated segmentation of tissue images for computerized IHC analysis  

Microsoft Academic Search

This paper presents two automated methods for the segmentation of immunohistochemical tissue images that overcome the limitations of the manual approach as well as of the existing computerized techniques. The first independent method, based on unsupervised color clustering, recognizes automatically the target cancerous areas in the specimen and disregards the stroma; the second method, based on colors separation and morphological

Santa Di Cataldo; Elisa Ficarra; Andrea Acquaviva; Enrico Macii

2010-01-01

123

Computed Tomographic Image Analysis Based on FEM Performance Comparison of Segmentation on Knee Joint Reconstruction  

PubMed Central

The demand for an accurate and accessible image segmentation to generate 3D models from CT scan data has been increasing as such models are required in many areas of orthopedics. In this paper, to find the optimal image segmentation to create a 3D model of the knee CT data, we compared and validated segmentation algorithms based on both objective comparisons and finite element (FE) analysis. For comparison purposes, we used 1 model reconstructed in accordance with the instructions of a clinical professional and 3 models reconstructed using image processing algorithms (Sobel operator, Laplacian of Gaussian operator, and Canny edge detection). Comparison was performed by inspecting intermodel morphological deviations with the iterative closest point (ICP) algorithm, and FE analysis was performed to examine the effects of the segmentation algorithm on the results of the knee joint movement analysis. PMID:25538950

Jang, Seong-Wook; Seo, Young-Jin; Yoo, Yon-Sik

2014-01-01

124

Theoretical analysis and experimental verification on valve-less piezoelectric pump with hemisphere-segment bluff-body  

NASA Astrophysics Data System (ADS)

Existing researches on no-moving part valves in valve-less piezoelectric pumps mainly concentrate on pipeline valves and chamber bottom valves, which leads to the complex structure and manufacturing process of pump channel and chamber bottom. Furthermore, position fixed valves with respect to the inlet and outlet also makes the adjustability and controllability of flow rate worse. In order to overcome these shortcomings, this paper puts forward a novel implantable structure of valve-less piezoelectric pump with hemisphere-segments in the pump chamber. Based on the theory of flow around bluff-body, the flow resistance on the spherical and round surface of hemisphere-segment is different when fluid flows through, and the macroscopic flow resistance differences thus formed are also different. A novel valve-less piezoelectric pump with hemisphere-segment bluff-body (HSBB) is presented and designed. HSBB is the no-moving part valve. By the method of volume and momentum comparison, the stress on the bluff-body in the pump chamber is analyzed. The essential reason of unidirectional fluid pumping is expounded, and the flow rate formula is obtained. To verify the theory, a prototype is produced. By using the prototype, experimental research on the relationship between flow rate, pressure difference, voltage, and frequency has been carried out, which proves the correctness of the above theory. This prototype has six hemisphere-segments in the chamber filled with water, and the effective diameter of the piezoelectric bimorph is 30mm. The experiment result shows that the flow rate can reach 0.50 mL/s at the frequency of 6 Hz and the voltage of 110 V. Besides, the pressure difference can reach 26.2 mm H2O at the frequency of 6 Hz and the voltage of 160 V. This research proposes a valve-less piezoelectric pump with hemisphere-segment bluff-body, and its validity and feasibility is verified through theoretical analysis and experiment.

Ji, Jing; Zhang, Jianhui; Xia, Qixiao; Wang, Shouyin; Huang, Jun; Zhao, Chunsheng

2014-05-01

125

Atlas-Based Segmentation Improves Consistency and Decreases Time Required for Contouring Postoperative Endometrial Cancer Nodal Volumes  

SciTech Connect

Purpose: Accurate target delineation of the nodal volumes is essential for three-dimensional conformal and intensity-modulated radiotherapy planning for endometrial cancer adjuvant therapy. We hypothesized that atlas-based segmentation ('autocontouring') would lead to time savings and more consistent contours among physicians. Methods and Materials: A reference anatomy atlas was constructed using the data from 15 postoperative endometrial cancer patients by contouring the pelvic nodal clinical target volume on the simulation computed tomography scan according to the Radiation Therapy Oncology Group 0418 trial using commercially available software. On the simulation computed tomography scans from 10 additional endometrial cancer patients, the nodal clinical target volume autocontours were generated. Three radiation oncologists corrected the autocontours and delineated the manual nodal contours under timed conditions while unaware of the other contours. The time difference was determined, and the overlap of the contours was calculated using Dice's coefficient. Results: For all physicians, manual contouring of the pelvic nodal target volumes and editing the autocontours required a mean {+-} standard deviation of 32 {+-} 9 vs. 23 {+-} 7 minutes, respectively (p = .000001), a 26% time savings. For each physician, the time required to delineate the manual contours vs. correcting the autocontours was 30 {+-} 3 vs. 21 {+-} 5 min (p = .003), 39 {+-} 12 vs. 30 {+-} 5 min (p = .055), and 29 {+-} 5 vs. 20 {+-} 5 min (p = .0002). The mean overlap increased from manual contouring (0.77) to correcting the autocontours (0.79; p = .038). Conclusion: The results of our study have shown that autocontouring leads to increased consistency and time savings when contouring the nodal target volumes for adjuvant treatment of endometrial cancer, although the autocontours still required careful editing to ensure that the lymph nodes at risk of recurrence are properly included in the target volume.

Young, Amy V. [Department of Radiation Oncology, Beth Israel Medical Center, New York, NY (Israel); Department of Radiation Oncology, St. Luke's-Roosevelt Hospital, New York, NY (United States); Wortham, Angela [Department of Radiation Oncology, State University of New York Health Science Center of Brooklyn, Brooklyn, NY (United States); Wernick, Iddo; Evans, Andrew [Department of Radiation Oncology, St. Luke's-Roosevelt Hospital, New York, NY (United States); Ennis, Ronald D., E-mail: REnnis@chpnet.or [Department of Radiation Oncology, St. Luke's-Roosevelt Hospital, New York, NY (United States)

2011-03-01

126

Volume analyzer SYNAPSE VINCENT for liver analysis.  

PubMed

In recent years, there has been an active movement to ensure the greater safety of actual surgeries, by simulating it preoperatively with the use of three-dimensional image visualization technologies. Along with this movement, the Ministry of Health, Labour and Welfare has named "Image-supported navigation in hepatectomy" as part of advanced medical techniques. This method aims to improve the safety during a surgery by calculating the volume of the liver dominated by each blood vessel or simulating, prior to surgery, the volume of resection zone or the remaining liver volume. These calculations and simulations are carried out using the three-dimensional images produced by extractions of the liver, vascular and tumor regions from the computed tomography images, which were collected using the tomography apparatus prior to hepatectomy. In order to facilitate the achievement of such preoperative simulations, the volume analyzer SYNAPSE VINCENT (VINCENT, hereafter) by Fujifilm, in its Liver Analysis Application, comes equipped with unique features. This paper will introduce the technologies behind those unique features and provide a direction for future research and developments. PMID:24520049

Ohshima, Shunsuke

2014-04-01

127

Volumetric brain analysis in neurosurgery: Part 1. Particle filter segmentation of brain and cerebrospinal fluid growth dynamics from MRI and CT images.  

PubMed

OBJECT Accurate edge tracing segmentation remains an incompletely solved problem in brain image analysis. The authors propose a novel algorithm using a particle filter to follow the boundary of the brain in the style often used in autonomous air and ground vehicle navigation. Their goals were to create a versatile tool to segment brain and fluid in MRI and CT images of the developing brain, lay the foundation for an intelligent automated edge tracker that is modality independent, and segment normative data from MRI that can be applied to both MRI and CT. METHODS Simulated MRI data sets were used to train and evaluate the particle filter segmentation algorithm. The method was then applied to produce normative growth curves for children and adolescents from 0 to 18 years of age for brain and fluid from MR images from the National Institutes of Health pediatric database and these data were compared to historical results. The authors further adapted this method for use with CT images of pediatric hydrocephalus and compared the results with hand-segmented data. RESULTS Segmentation of simulated MRI data with varied levels of noise (0%-9%) and spatial inhomogeneity (0%-40%) resulted in percent errors ranging from 0.06% to 5.38% for brain volume and 2.45% to 22.3% for fluid volume. The authors used this tool to create normal brain and CSF growth curves from MR images. The calculated growth curves showed excellent consistency with historical data. Additionally, compared with manual segmentation the particle filter accurately segmented brain and fluid volumes from CT scans of 5 pediatric patients with hydrocephalus (p < 0.001). CONCLUSIONS The authors have produced the first normative brain and CSF growth curves for children and adolescents 0-18 years of age. In addition, this study includes the first use of a particle filter as an edge tracker in image segmentation and offers a semiautomatic method to segment both pediatric and adult brain data from MR and CT images. The particle filter has the potential to be further automated toward a clinical rather than research tool with both of these modalities. Because of its modality independence, it has the capability to allow CT to be a more effective diagnostic tool for neurological disorders, a task of substantial importance in emergency settings and in developing countries where CT is often the only available method of brain imaging. PMID:25431902

Mandell, Jason G; Langelaan, Jack W; Webb, Andrew G; Schiff, Steven J

2015-02-01

128

Automated abdominal lymph node segmentation based on RST analysis and SVM  

NASA Astrophysics Data System (ADS)

This paper describes a segmentation method for abdominal lymph node (LN) using radial structure tensor analysis (RST) and support vector machine. LN analysis is one of crucial parts of lymphadenectomy, which is a surgical procedure to remove one or more LNs in order to evaluate them for the presence of cancer. Several works for automated LN detection and segmentation have been proposed. However, there are a lot of false positives (FPs). The proposed method consists of LN candidate segmentation and FP reduction. LN candidates are extracted using RST analysis in each voxel of CT scan. RST analysis can discriminate between difference local intensity structures without influence of surrounding structures. In FP reduction process, we eliminate FPs using support vector machine with shape and intensity information of the LN candidates. The experimental result reveals that the sensitivity of the proposed method was 82.0 % with 21.6 FPs/case.

Nimura, Yukitaka; Hayashi, Yuichiro; Kitasaka, Takayuki; Furukawa, Kazuhiro; Misawa, Kazunari; Mori, Kensaku

2014-03-01

129

Comparative Study of Segmentation of Periodic Motion Data for Mobile Gait Analysis  

E-print Network

Comparative Study of Segmentation of Periodic Motion Data for Mobile Gait Analysis Aris Valtazanos for mobile gait analysis. The first is a basic, model-based algorithm which operates directly on the joint in a hospital-based clinical study for analysing the motion of elderly patients recovering from a fall. Keywords

130

Mathematical Analysis of Space Radiator Segmenting for Increased Reliability and Reduced Mass  

NASA Technical Reports Server (NTRS)

Spacecraft for long duration deep space missions will need to be designed to survive micrometeoroid bombardment of their surfaces some of which may actually be punctured. To avoid loss of the entire mission the damage due to such punctures must be limited to small, localized areas. This is especially true for power system radiators, which necessarily feature large surface areas to reject heat at relatively low temperature to the space environment by thermal radiation. It may be intuitively obvious that if a space radiator is composed of a large number of independently operating segments, such as heat pipes, a random micrometeoroid puncture will result only in the loss of the punctured segment, and not the entire radiator. Due to the redundancy achieved by independently operating segments, the wall thickness and consequently the weight of such segments can be drastically reduced. Probability theory is used to estimate the magnitude of such weight reductions as the number of segments is increased. An analysis of relevant parameter values required for minimum mass segmented radiators is also included.

Juhasz, Albert J.

2001-01-01

131

Automated image segmentation for breast analysis using infrared images  

Microsoft Academic Search

In order to realize a fully automated thermogram analysis package for breast cancer detection, it is necessary to identify the region of interest in the thermal image prior to analysis. A nearly fully automated approach is outlined that is able to successfully locate the breast regions in most of the images analyzed. The approach consists of a sequence of Canny

N. Scales; C. Kerry; M. Prize

2004-01-01

132

Morphotectonic Index Analysis as an Indicator of Neotectonic Segmentation of the Nicoya Peninsula, Costa Rica  

NASA Astrophysics Data System (ADS)

The Nicoya Peninsula lies within the Costa Rican forearc where the Cocos plate subducts under the Caribbean plate at ~8.5 cm/yr. Rapid plate convergence produces frequent large earthquakes (~50yr recurrence interval) and pronounced crustal deformation (0.1-2.0m/ky uplift). Seven uplifted segments have been identified in previous studies using broad geomorphic surfaces (Hare & Gardner 1984) and late Quaternary marine terraces (Marshall et al. 2010). These surfaces suggest long term net uplift and segmentation of the peninsula in response to contrasting domains of subducting seafloor (EPR, CNS-1, CNS-2). In this study, newer 10m contour digital topographic data (CENIGA- Terra Project) will be used to characterize and delineate this segmentation using morphotectonic analysis of drainage basins and correlation of fluvial terrace/ geomorphic surface elevations. The peninsula has six primary watersheds which drain into the Pacific Ocean; the Río Andamojo, Río Tabaco, Río Nosara, Río Ora, Río Bongo, and Río Ario which range in area from 200 km2 to 350 km2. The trunk rivers follow major lineaments that define morphotectonic segment boundaries and in turn their drainage basins are bisected by them. Morphometric analysis of the lower (1st and 2nd) order drainage basins will provide insight into segmented tectonic uplift and deformation by comparing values of drainage basin asymmetry, stream length gradient, and hypsometry with respect to margin segmentation and subducting seafloor domain. A general geomorphic analysis will be conducted alongside the morphometric analysis to map previously recognized (Morrish et al. 2010) but poorly characterized late Quaternary fluvial terraces. Stream capture and drainage divide migration are common processes throughout the peninsula in response to the ongoing deformation. Identification and characterization of basin piracy throughout the peninsula will provide insight into the history of landscape evolution in response to differential uplift. Conducting this morphotectonic analysis of the Nicoya Peninsula will provide further constraints on rates of segment uplift, location of segment boundaries, and advance the understanding of the long term deformation of the region in relation to subduction.

Morrish, S.; Marshall, J. S.

2013-12-01

133

Scientific and clinical evidence for the use of fetal ECG ST segment analysis (STAN).  

PubMed

Fetal electrocardiogram waveform analysis has been studied for many decades, but it is only in the last 20 years that computerization has made real-time analysis practical for clinical use. Changes in the ST segment have been shown to correlate with fetal condition, in particular with acid-base status. Meta-analysis of randomized trials (five in total, four using the computerized system) has shown that use of computerized ST segment analysis (STAN) reduces the need for fetal blood sampling by about 40%. However, although there are trends to lower rates of low Apgar scores and acidosis, the differences are not statistically significant. There is no effect on cesarean section rates. Disadvantages include the need for amniotic membranes to be ruptured so that a fetal scalp electrode can be applied, and the need for STAN values to be interpreted in conjunction with detailed fetal heart rate pattern analysis. PMID:24597897

Steer, Philip J; Hvidman, Lone Egly

2014-06-01

134

Vessel Segmentation and Analysis in Laboratory Skin Transplant Micro-angiograms  

E-print Network

Vessel Segmentation and Analysis in Laboratory Skin Transplant Micro-angiograms Alexandru transplantations depends on the adequate revascularization of the trans- planted dermal matrix. To induce vessel recorded after the injection of a radiopaque substance) of tissue transplanted on the back of laboratory

Lübeck, Universität zu

135

Texture analysis and segmentation using modulation features, generative models, and weighted curve evolution.  

PubMed

In this work we approach the analysis and segmentation of natural textured images by combining ideas from image analysis and probabilistic modeling. We rely on AM-FM texture models and specifically on the Dominant Component Analysis (DCA) paradigm for feature extraction. This method provides a low-dimensional, dense and smooth descriptor, capturing essential aspects of texture, namely scale, orientation, and contrast. Our contributions are at three levels of the texture analysis and segmentation problems: First, at the feature extraction stage we propose a Regularized Demodulation Algorithm that provides more robust texture features and explore the merits of modifying the channel selection criterion of DCA. Second, we propose a probabilistic interpretation of DCA and Gabor filtering in general, in terms of Local Generative Models. Extending this point of view to edge detection facilitates the estimation of posterior probabilities for the edge and texture classes. Third, we propose the Weighted Curve Evolution scheme that enhances the Region Competition/ Geodesic Active Regions methods by allowing for the locally adaptive fusion of heterogeneous cues. Our segmentation results are evaluated on the Berkeley Segmentation Benchmark, and compare favorably to current state-of-the-art methods. PMID:19029552

Kokkinos, Iasonas; Evangelopoulos, Georgios; Maragos, Petros

2009-01-01

136

Analysis of a Segmented Brushless PM Machine Utilising Soft Magnetic Composites  

Microsoft Academic Search

Soft magnetic composites (SMC) is a magnetic material which offers the potential for innovative machine geometries and lower cost manufacturing. This paper examines the finite-element analysis and performance prediction of a segmented brushless permanent magnet machine based on SMC. Experimental results including the back-EMF waveform, iron loss and performance characteristics are used to validate the simulation results.

G. S. Liew; E. C. Y. Tsang; N. Ertugrul; W. L. Soong; D. Atkinson; D. B. Gehlert

2007-01-01

137

SHAPE-CONSTRAINED SEGMENTATION APPROACH FOR ARCTIC MULTIYEAR SEA ICE FLOE ANALYSIS  

E-print Network

SHAPE-CONSTRAINED SEGMENTATION APPROACH FOR ARCTIC MULTIYEAR SEA ICE FLOE ANALYSIS Yuliya Tarabalka Research Association, MD, USA. e-mail: yuliya.tarabalka@inria.fr ABSTRACT The melting of sea ice, it is important to investigate how rapidly sea ice floes melt. For this purpose, a new TempoSeg method

Boyer, Edmond

138

A comparison of segmental and wrist-to-ankle methodologies of bioimpedance analysis  

Microsoft Academic Search

The common approach of bioelectrical impedance analysis to estimate body water uses a wrist-to-ankle methodology which, although not indicated by theory, has the advantage of ease of application particularly for clinical studies involving patients with debilitating diseases. A number of authors have suggested the use of a segmented protocol in which the impedances of the trunk and limbs are measured

B. J. Thomas; B. H. Cornish; L. C. Ward; M. A. Patterson

1998-01-01

139

Loads analysis and testing of flight configuration solid rocket motor outer boot ring segments  

NASA Technical Reports Server (NTRS)

The loads testing on in-house-fabricated flight configuration Solid Rocket Motor (SRM) outer boot ring segments. The tests determined the bending strength and bending stiffness of these beams and showed that they compared well with the hand analysis. The bending stiffness test results compared very well with the finite element data.

Ahmed, Rafiq

1990-01-01

140

Tie-Zone Watershed, Bottlenecks and Segmentation Robustness Analysis Romaric Audigier, Roberto de Alencar Lotufo  

E-print Network

Tie-Zone Watershed, Bottlenecks and Segmentation Robustness Analysis Romaric Audigier, Roberto de.dca.fee.unicamp.br/lotufo Abstract In a recent paper [1], a new type of watershed (WS) transform was introduced: the tie-zone watershed (TZWS). This region-based watershed transform does not depend on arbitrary implementation

Cord, Aurélien

141

Reliable Cell Segmentation Based on Spectral Phasor Analysis of Hyperspectral Stimulated Raman Scattering Imaging Data  

E-print Network

Reliable Cell Segmentation Based on Spectral Phasor Analysis of Hyperspectral Stimulated Raman Scattering Imaging Data Dan Fu and X. Sunney Xie* Department of Chemistry and Chemical Biology, Harvard stimulated Raman scattering (SRS) imaging has rapidly become an emerging tool for high content analyses

Xie, Xiaoliang Sunney

142

Tip-tilt error for extremely large segmented telescopes: detailed theoretical point-spread-function analysis and numerical simulation results  

Microsoft Academic Search

We present an analysis of point-spread functions for segmented mirrors affected by random tip-tilt errors on each segment. In addition to Strehl ratio evaluation, this analysis considers key characteristics such as the intensity and the location of speckles and secondary peaks and the relative energy distribution between these features. We develop a method to describe the shape of a nonaveraged

Natalia Yaitskova; Kjetil Dohlen

2002-01-01

143

Cortical Surface-Based Analysis I. Segmentation and Surface Reconstruction  

E-print Network

cortex, which makes up the largest part of the human brain, has the topology of a 2-D sheet and a highly use of cortical surface-based analysis and visualization meth- ods in functional brain imaging. 1999 have been rou- tinely applied. Nevertheless, most approaches to analyz- ing and displaying human brain

Sereno, Martin

144

Image segmentation and analysis via multiscale gradient watershed hierarchies  

Microsoft Academic Search

Multiscale image analysis has been used successfully in a number of applications to classify image features according to their relative scales. As a consequence, much has been learned about the scale-space behavior of intensity extrema, edges, intensity ridges, and grey-level blobs. We investigate the multiscale behavior of gradient watershed regions. These regions are defined in terms of the gradient properties

John M. Gauch

1999-01-01

145

Segmentation of dynamic PET images using cluster analysis  

Microsoft Academic Search

Quantitative positron emission tomography (PET) studies provide in vivo measurements of dynamic physiological and biochemical processes in humans. A limitation of PET is an inability to provide precise anatomic localization due to relatively poor spatial resolution when compared to magnetic resonance (MR) imaging. Manual placement of region-of-interest (ROI) is commonly used in clinical and research settings in analysis of PET

Koon-Pong Wong; Dagan Feng; Steven R. Meikle; Michael J. Fulham

2002-01-01

146

Genetic and expression analysis of enabled in Drosophila leg segmentation  

E-print Network

and it is excluded from cells where N signaling is active. Ena is also shown to be enriched at the adherens junctions, suggesting a role in adherens junctions formation/maintenance or signaling at these junctions. Phenotypic analysis suggests that ena? is cell lethal...

Ramel, Marie-Christine

2001-01-01

147

Audio Feature Extraction and Analysis for Scene Segmentation and Classification  

Microsoft Academic Search

Understanding of the scene content of a video sequence is very important for content-based indexing and retrieval of multimedia databases. Research in this area in the past several years has focused on the use of speech recognition and image analysis techniques. As a complimentary effort to the prior work, we have focused on using the associated audio information (mainly the

Zhu Liu; Yao Wang; Tsuhan Chen

1998-01-01

148

Segmental analysis of indocyanine green pharmacokinetics for the reliable diagnosis of functional vascular insufficiency  

NASA Astrophysics Data System (ADS)

Accurate and reliable diagnosis of functional insufficiency of peripheral vasculature is essential since Raynaud phenomenon (RP), most common form of peripheral vascular insufficiency, is commonly associated with systemic vascular disorders. We have previously demonstrated that dynamic imaging of near-infrared fluorophore indocyanine green (ICG) can be a noninvasive and sensitive tool to measure tissue perfusion. In the present study, we demonstrated that combined analysis of multiple parameters, especially onset time and modified Tmax which means the time from onset of ICG fluorescence to Tmax, can be used as a reliable diagnostic tool for RP. To validate the method, we performed the conventional thermographic analysis combined with cold challenge and rewarming along with ICG dynamic imaging and segmental analysis. A case-control analysis demonstrated that segmental pattern of ICG dynamics in both hands was significantly different between normal and RP case, suggesting the possibility of clinical application of this novel method for the convenient and reliable diagnosis of RP.

Kang, Yujung; Lee, Jungsul; An, Yuri; Jeon, Jongwook; Choi, Chulhee

2011-03-01

149

Tracking and data acquisition system for the 1990's. Volume 5: TDAS ground segment architecture and operations concept  

NASA Technical Reports Server (NTRS)

Tracking and data acquisition system (TDAS) ground segment and operational requirements, TDAS RF terminal configurations, TDAS ground segment elements, the TDAS network, and the TDAS ground terminal hardware are discussed.

Daly, R.

1983-01-01

150

Sum of segmental bioimpedance analysis during ultrafiltration and hemodialysis reduces sensitivity to changes in body position  

Microsoft Academic Search

Sum of segmental bioimpedance analysis during ultrafiltration and hemodialysis reduces sensitivity to changes in body position.BackgroundBioimpedance, a noninvasive technique to analyze body composition, has attracted interest in determining body hydration in hemodialysis patients. However, the so-called whole-body (wrist-to-ankle) bioimpedance analysis (WBIA) is sensitive to changes in regional fluid distribution and tends to underestimate fluid changes during ultrafiltration in hemodialysis patients.

Fansan Zhu; Daniel Schneditz; Nathan W. Levin

1999-01-01

151

Segmentation of the Knee for Analysis of Osteoarthritis  

NASA Astrophysics Data System (ADS)

Osteoarthritis changes the load distribution within joints and also changes bone density and structure. Within typical timelines of clinical studies these changes can be very small. Therefore precise definition of evaluation regions which are highly robust and show little to no interand intra-operator variance are essential for high quality quantitative analysis. To achieve this goal we have developed a system for the definition of such regions with minimal user input.

Zerfass, Peter; Museyko, Oleg; Bousson, Valérie; Laredo, Jean-Denis; Kalender, Willi A.; Engelke, Klaus

152

Molecular Plant Volume 4 Number 5 Pages 922931 September 2011 RESEARCH ARTICLE Adaptive Cell Segmentation and Tracking for  

E-print Network

, Riverside, CA, USA ABSTRACT Automated segmentation and tracking of cells in actively developing tissues can in its ability to segment and track cells in densely packed tissue, the shoot apical meristem (SAM separately. Key words: Shoot apical meristem; stem cells; cell tracking; cell segmentation; integrated

Chowdhury, Amit K. Roy

153

Automated iterative neutrosophic lung segmentation for image analysis in thoracic computed tomography  

PubMed Central

Purpose: Lung segmentation is a fundamental step in many image analysis applications for lung diseases and abnormalities in thoracic computed tomography (CT). The authors have previously developed a lung segmentation method based on expectation-maximization (EM) analysis and morphological operations (EMM) for our computer-aided detection (CAD) system for pulmonary embolism (PE) in CT pulmonary angiography (CTPA). However, due to the large variations in pathology that may be present in thoracic CT images, it is difficult to extract the lung regions accurately, especially when the lung parenchyma contains extensive lung diseases. The purpose of this study is to develop a new method that can provide accurate lung segmentation, including those affected by lung diseases. Methods: An iterative neutrosophic lung segmentation (INLS) method was developed to improve the EMM segmentation utilizing the anatomic features of the ribs and lungs. The initial lung regions (ILRs) were extracted using our previously developed EMM method, in which the ribs were extracted using 3D hierarchical EM segmentation and the ribcage was constructed using morphological operations. Based on the anatomic features of ribs and lungs, the initial EMM segmentation was refined using INLS to obtain the final lung regions. In the INLS method, the anatomic features were mapped into a neutrosophic domain, and the neutrosophic operation was performed iteratively to refine the ILRs. With IRB approval, 5 and 58 CTPA scans were collected retrospectively and used as training and test sets, of which 2 and 34 cases had lung diseases, respectively. The lung regions manually outlined by an experienced thoracic radiologist were used as reference standard for performance evaluation of the automated lung segmentation. The percentage overlap area (POA), the Hausdorff distance (Hdist), and the average distance (AvgDist) of the lung boundaries relative to the reference standard were used as performance metrics. Results: The proposed method achieved larger POAs and smaller distance errors than the EMM method. For the 58 test cases, the average POA, Hdist, and AvgDist were improved from 85.4 ± 18.4%, 22.6 ± 29.4 mm, and 3.5 ± 5.4 mm using EMM to 91.2 ± 6.7%, 16.0 ± 11.3 mm, and 2.5 ± 1.0 mm using INLS, respectively. The improvements were statistically significant (p < 0.05). To evaluate the accuracy of the INLS method in the identification of the lung boundaries affected by lung diseases, the authors separately analyzed the performance of the proposed method on the cases with versus without the lung diseases. The results showed that the cases without lung diseases were segmented more accurately than the cases with lung diseases by both the EMM and the INLS methods, but the INLS method achieved better performance than the EMM method in both cases. Conclusions: The new INLS method utilizing the anatomic features of the rib and lung significantly improved the accuracy of lung segmentation, especially for the cases affected by lung diseases. Improvement in lung segmentation will facilitate many image analysis tasks and CAD applications for lung diseases and abnormalities in thoracic CT, including automated PE detection. PMID:23927326

Guo, Yanhui; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Wei, Jun; Hadjiiski, Lubomir M.; Kazerooni, Ella A.

2013-01-01

154

Predictive Value of Admission Platelet Volume Indices for In-hospital Major Adverse Cardiovascular Events in Acute ST-Segment Elevation Myocardial Infarction.  

PubMed

Although mean platelet volume (MPV) is an independent correlate of impaired angiographic reperfusion and 6-month mortality in ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI), there is less data regarding the association between platelet distribution width (PDW) and in-hospital major adverse cardiovascular events (MACEs). A total of 306 patients with STEMI pPCI were evaluated. No reflow was defined as a post-PCI thrombolysis in myocardial infarction (TIMI) flow grade of 0, 1, or 2 (group 1). Angiographic success was defined as TIMI flow grade 3 (group 2). The values of MPV and PDW were higher among patients with no reflow. In-stent thrombosis, nonfatal myocardial infarction, in-hospital mortality, and MACEs were significantly more frequent among patients with no reflow. In multivariate analysis, PDW, MPV, high-sensitivity C-reactive protein, and glucose on admission were independent correlates of in-hospital MACEs. Admission PDW and MPV are independent correlates of no reflow and in-hospital MACEs among patients with STEMI undergoing pPCI. PMID:24301422

Celik, Turgay; Kaya, Mehmet G; Akpek, Mahmut; Gunebakmaz, Ozgur; Balta, Sevket; Sarli, Bahadir; Duran, Mustafa; Demirkol, Sait; Uysal, Onur Kadir; Oguzhan, Abdurrahman; Gibson, C Michael

2015-02-01

155

Integrated Software for the Analysis of Brain PET\\/SPECT Studies with Partial-Volume-Effect Correction  

Microsoft Academic Search

We present software for integrated analysis of brain PET studies and coregistered segmented MRI that couples a module for automated placement of regions of interest (ROI) with 4 alter- native methods for partial-volume-effect correction (PVEc). The accuracy and precision of these methods have been measured using 4 simulated 18F-FDG PET studies with increasing degrees of atrophy. Methods: The software allows

Mario Quarantelli; Karim Berkouk; Anna Prinster; Brigitte Landeau; Claus Svarer; Laszlo Balkay; Bruno Alfano; Arturo Brunetti; Jean-Claude Baron; Marco Salvatore

2004-01-01

156

Relationship between Stroke Volume and Pulse Pressure during Blood Volume Perturbation: A Mathematical Analysis  

PubMed Central

Arterial pulse pressure has been widely used as surrogate of stroke volume, for example, in the guidance of fluid therapy. However, recent experimental investigations suggest that arterial pulse pressure is not linearly proportional to stroke volume. However, mechanisms underlying the relation between the two have not been clearly understood. The goal of this study was to elucidate how arterial pulse pressure and stroke volume respond to a perturbation in the left ventricular blood volume based on a systematic mathematical analysis. Both our mathematical analysis and experimental data showed that the relative change in arterial pulse pressure due to a left ventricular blood volume perturbation was consistently smaller than the corresponding relative change in stroke volume, due to the nonlinear left ventricular pressure-volume relation during diastole that reduces the sensitivity of arterial pulse pressure to perturbations in the left ventricular blood volume. Therefore, arterial pulse pressure must be used with care when used as surrogate of stroke volume in guiding fluid therapy. PMID:25006577

2014-01-01

157

Validity of a computer-assisted manual segmentation software to quantify wrist erosion volume using computed tomography scans in rheumatoid arthritis  

PubMed Central

Background To investigate the performance of conventional radiography (CR) for the detection of bone erosions of wrist in rheumatoid arthritis (RA) using multidetector computed tomography (CT) as the reference method and to evaluate the validity of a computer-assisted manual segmentation (outlining) technique to quantify erosion volume on CT scans. Methods Twenty five RA patients and six controls underwent CT and radiographic evaluation of the dominant wrist on the same day. CT was performed by using a 64 GE light Speed VCT power. Wrists images were evaluated separately and scored for the presence of erosions according to the Outcome Measures in Rheumatology Rheumatoid Arthritis MRI Scoring System (RAMRIS) and the Sharp/van der Heijde scoring method. Measurements of bone erosion volumes were obtained using OsiriX medical imaging software. The mean value of the volumes of the CT bone erosions detected at two readings was used to calculate inter-rater agreement. Results The overall sensitivity, specificity and accuracy of radiography for detecting erosions were 25.5%, 98.3% and 70.1%, respectively. Using computer-assisted manual segmentation (outlining) technique, erosion volume on CT measurements per subject was ranged from 0.001 cm3 to 2.01 cm3. Spearman’s RAMRIS score of each wrist bones in all subjects (n?=?25) were correlated with the total erosion volume on CT (p?volume and the corresponding bone volume on a percentage basis (p?segmentation showed high agreement (ICC?=?0.901). Conclusions Considering CT as the reference method, CR showed very low sensitivity. A close correlation with CT erosion volumes supports the OMERACT RAMRIS erosion score as a semiquantitative measure of joint damage in RA. Although the computer-assisted manual segmentation can be beneficial for diagnostic decision in cross-sectional CT examinations of the wrist in RA, this technique will require further evaluation in terms of responsiveness. PMID:24028158

2013-01-01

158

Stress Analysis of Bolted, Segmented Cylindrical Shells Exhibiting Flange Mating-Surface Waviness  

NASA Technical Reports Server (NTRS)

Bolted, segmented cylindrical shells are a common structural component in many engineering systems especially for aerospace launch vehicles. Segmented shells are often needed due to limitations of manufacturing capabilities or transportation issues related to very long, large-diameter cylindrical shells. These cylindrical shells typically have a flange or ring welded to opposite ends so that shell segments can be mated together and bolted to form a larger structural system. As the diameter of these shells increases, maintaining strict fabrication tolerances for the flanges to be flat and parallel on a welded structure is an extreme challenge. Local fit-up stresses develop in the structure due to flange mating-surface mismatch (flange waviness). These local stresses need to be considered when predicting a critical initial flaw size. Flange waviness is one contributor to the fit-up stress state. The present paper describes the modeling and analysis effort to simulate fit-up stresses due to flange waviness in a typical bolted, segmented cylindrical shell. Results from parametric studies are presented for various flange mating-surface waviness distributions and amplitudes.

Knight, Norman F., Jr.; Phillips, Dawn R.; Raju, Ivatury S.

2009-01-01

159

Automated segmentation of muscle and adipose tissue on CT images for human body composition analysis  

NASA Astrophysics Data System (ADS)

The ability to compute body composition in cancer patients lends itself to determining the specific clinical outcomes associated with fat and lean tissue stores. For example, a wasting syndrome of advanced disease associates with shortened survival. Moreover, certain tissue compartments represent sites for drug distribution and are likely determinants of chemotherapy efficacy and toxicity. CT images are abundant, but these cannot be fully exploited unless there exist practical and fast approaches for tissue quantification. Here we propose a fully automated method for segmenting muscle, visceral and subcutaneous adipose tissues, taking the approach of shape modeling for the analysis of skeletal muscle. Muscle shape is represented using PCA encoded Free Form Deformations with respect to a mean shape. The shape model is learned from manually segmented images and used in conjunction with a tissue appearance prior. VAT and SAT are segmented based on the final deformed muscle shape. In comparing the automatic and manual methods, coefficients of variation (COV) (1 - 2%), were similar to or smaller than inter- and intra-observer COVs reported for manual segmentation.

Chung, Howard; Cobzas, Dana; Birdsell, Laura; Lieffers, Jessica; Baracos, Vickie

2009-02-01

160

Analysis of gene expression levels in individual bacterial cells without image segmentation  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We present a method for extracting gene expression data from images of bacterial cells. Black-Right-Pointing-Pointer The method does not employ cell segmentation and does not require high magnification. Black-Right-Pointing-Pointer Fluorescence and phase contrast images of the cells are correlated through the physics of phase contrast. Black-Right-Pointing-Pointer We demonstrate the method by characterizing noisy expression of comX in Streptococcus mutans. -- Abstract: Studies of stochasticity in gene expression typically make use of fluorescent protein reporters, which permit the measurement of expression levels within individual cells by fluorescence microscopy. Analysis of such microscopy images is almost invariably based on a segmentation algorithm, where the image of a cell or cluster is analyzed mathematically to delineate individual cell boundaries. However segmentation can be ineffective for studying bacterial cells or clusters, especially at lower magnification, where outlines of individual cells are poorly resolved. Here we demonstrate an alternative method for analyzing such images without segmentation. The method employs a comparison between the pixel brightness in phase contrast vs fluorescence microscopy images. By fitting the correlation between phase contrast and fluorescence intensity to a physical model, we obtain well-defined estimates for the different levels of gene expression that are present in the cell or cluster. The method reveals the boundaries of the individual cells, even if the source images lack the resolution to show these boundaries clearly.

Kwak, In Hae; Son, Minjun [Physics Department, University of Florida, P.O. Box 118440, Gainesville, FL 32611-8440 (United States)] [Physics Department, University of Florida, P.O. Box 118440, Gainesville, FL 32611-8440 (United States); Hagen, Stephen J., E-mail: sjhagen@ufl.edu [Physics Department, University of Florida, P.O. Box 118440, Gainesville, FL 32611-8440 (United States)

2012-05-11

161

LV volume quantification via spatiotemporal analysis of real-time 3-D echocardiography.  

PubMed

This paper presents a method of four-dimensional (4-D) (3-D + Time) space-frequency analysis for directional denoising and enhancement of real-time three-dimensional (RT3D) ultrasound and quantitative measures in diagnostic cardiac ultrasound. Expansion of echocardiographic volumes is performed with complex exponential wavelet-like basis functions called brushlets. These functions offer good localization in time and frequency and decompose a signal into distinct patterns of oriented harmonics, which are invariant to intensity and contrast range. Deformable-model segmentation is carried out on denoised data after thresholding of transform coefficients. This process attenuates speckle noise while preserving cardiac structure location. The superiority of 4-D over 3-D analysis for decorrelating additive white noise and multiplicative speckle noise on a 4-D phantom volume expanding in time is demonstrated. Quantitative validation, computed for contours and volumes, is performed on in vitro balloon phantoms. Clinical applications of this spaciotemporal analysis tool are reported for six patient cases providing measures of left ventricular volumes and ejection fraction. PMID:11437106

Angelini, E D; Laine, A F; Takuma, S; Holmes, J W; Homma, S

2001-06-01

162

Segmentation of multiple sclerosis lesions in intensity corrected multispectral MRI  

Microsoft Academic Search

To segment brain tissues in magnetic resonance images of the brain, the authors have implemented a stochastic relaxation method which utilizes partial volume analysis for every brain voxel, and operates on fully three-dimensional (3-D) data. However, there are still problems with automatically or semi-automatically segmenting thick magnetic resonance (MR) slices, particularly when trying to segment the small lesions present in

B. Johnston; M. S. Atkins; B. Mackiewich; M. Anderson

1996-01-01

163

Non-segmental analysis and synthesis based on a speech database  

Microsoft Academic Search

This paper reports on experiments in non-segmental sp eech analysis and synthesis using parameters derived from a speech database of British English monosyllables. The database includes almost every onset, nucleus and coda, and almost all onset-nucleus and nucleus-consonant combinations occurring in English. Acoustic parameters including f0, formant frequencies and bandwidths, and amplitude of voicing were determined for each token in

Andrew Slater; John Coleman

1996-01-01

164

Productivity AnalysisIn the On-site Food-service Segment  

Microsoft Academic Search

On-site food service has evolved into a major segment of the multiunit restaurant industry, with 1998 sales expected to exceed $80 billion. Surprisingly, productivity analysis of on-site food service is still performed using measures that fail to capture the complexity of today's operations. Traditional partial-factor productivity measures do not account for relationships among resources. Labor productivity, in particular, is often

Dennis Reynolds

1998-01-01

165

Fetal autonomic brain age scores, segmented heart rate variability analysis, and traditional short term variability.  

PubMed

Disturbances of fetal autonomic brain development can be evaluated from fetal heart rate patterns (HRP) reflecting the activity of the autonomic nervous system. Although HRP analysis from cardiotocographic (CTG) recordings is established for fetal surveillance, temporal resolution is low. Fetal magnetocardiography (MCG), however, provides stable continuous recordings at a higher temporal resolution combined with a more precise heart rate variability (HRV) analysis. A direct comparison of CTG and MCG based HRV analysis is pending. The aims of the present study are: (i) to compare the fetal maturation age predicting value of the MCG based fetal Autonomic Brain Age Score (fABAS) approach with that of CTG based Dawes-Redman methodology; and (ii) to elaborate fABAS methodology by segmentation according to fetal behavioral states and HRP. We investigated MCG recordings from 418 normal fetuses, aged between 21 and 40 weeks of gestation. In linear regression models we obtained an age predicting value of CTG compatible short term variability (STV) of R (2) = 0.200 (coefficient of determination) in contrast to MCG/fABAS related multivariate models with R (2) = 0.648 in 30 min recordings, R (2) = 0.610 in active sleep segments of 10 min, and R (2) = 0.626 in quiet sleep segments of 10 min. Additionally segmented analysis under particular exclusion of accelerations (AC) and decelerations (DC) in quiet sleep resulted in a novel multivariate model with R (2) = 0.706. According to our results, fMCG based fABAS may provide a promising tool for the estimation of fetal autonomic brain age. Beside other traditional and novel HRV indices as possible indicators of developmental disturbances, the establishment of a fABAS score normogram may represent a specific reference. The present results are intended to contribute to further exploration and validation using independent data sets and multicenter research structures. PMID:25505399

Hoyer, Dirk; Kowalski, Eva-Maria; Schmidt, Alexander; Tetschke, Florian; Nowack, Samuel; Rudolph, Anja; Wallwitz, Ulrike; Kynass, Isabelle; Bode, Franziska; Tegtmeyer, Janine; Kumm, Kathrin; Moraru, Liviu; Götz, Theresa; Haueisen, Jens; Witte, Otto W; Schleußner, Ekkehard; Schneider, Uwe

2014-01-01

166

Buckling Design and Analysis of a Payload Fairing One-Sixth Cylindrical Arc-Segment Panel  

NASA Technical Reports Server (NTRS)

Design and analysis results are reported for a panel that is a 16th arc-segment of a full 33-ft diameter cylindrical barrel section of a payload fairing structure. Six such panels could be used to construct the fairing barrel, and, as such, compression buckling testing of a 16th arc-segment panel would serve as a validation test of the buckling analyses used to design the fairing panels. In this report, linear and nonlinear buckling analyses have been performed using finite element software for 16th arc-segment panels composed of aluminum honeycomb core with graphiteepoxy composite facesheets and an alternative fiber reinforced foam (FRF) composite sandwich design. The cross sections of both concepts were sized to represent realistic Space Launch Systems (SLS) Payload Fairing panels. Based on shell-based linear buckling analyses, smaller, more manageable buckling test panel dimensions were determined such that the panel would still be expected to buckle with a circumferential (as opposed to column-like) mode with significant separation between the first and second buckling modes. More detailed nonlinear buckling analyses were then conducted for honeycomb panels of various sizes using both Abaqus and ANSYS finite element codes, and for the smaller size panel, a solid-based finite element analysis was conducted. Finally, for the smaller size FRF panel, nonlinear buckling analysis was performed wherein geometric imperfections measured from an actual manufactured FRF were included. It was found that the measured imperfection did not significantly affect the panel's predicted buckling response

Kosareo, Daniel N.; Oliver, Stanley T.; Bednarcyk, Brett A.

2013-01-01

167

Combined Finite Element --Finite Volume Method ( Convergence Analysis )  

E-print Network

Combined Finite Element -- Finite Volume Method ( Convergence Analysis ) M'aria Luk idea is to combine finite volume and finite element methods in an appropriate way. Thus nonlinear grid. Diffusion terms are discretized by the conforming piecewise linear finite element method

Magdeburg, Universität

168

FIELD VALIDATION OF EXPOSURE ASSESSMENT MODELS. VOLUME 2. ANALYSIS  

EPA Science Inventory

This is the second of two volumes describing a series of dual tracer experiments designed to evaluate the PAL-DS model, a Gaussian diffusion model modified to take into account settling and deposition, as well as three other deposition models. In this volume, an analysis of the d...

169

Methods of analysis of nonstationary EEGs, with emphasis on segmentation techniques: a comparative review.  

PubMed

Methods for analysis of nonstationary EEGs, that is, EEGs whose patterns undergo changes with time (e.g., alpha blocking, paroxysmal slow waves, onset of drowsiness/sleep, but excluding spikes/sharp waves) are reviewed. The concepts of stationarity and nonstationarity, and general techniques for their evaluation, are discussed. Simpler methods for monitoring for nonstationarity include running determinations of average amplitude and average period or interval. Piecewise stationary analysis includes characterization, by spectra obtained by fast Fourier transform or by autoregressive modeling, of sections of EEGs preselected to be stationary. In Kalman filtering, the autoregressive model itself becomes time-varying. Segmentation of the EEG into stationary lengths can be carried out on a fixed-interval basis (i.e., of successive, e.g., 1-s intervals), with clustering (grouping) or classification according to the features (e.g., spectra) of each interval, and concatenation of adjacent similar intervals. Alternatively, in adaptive (variable-interval) segmentation, the EEG is continuously monitored automatically for any significant departure from stationarity, and segment boundaries are placed accordingly. A number of applications of the various methods are included, with examples of succinct summary displays. Problems and prospects are discussed. PMID:3916847

Barlow, J S

1985-07-01

170

Guidance for Environmental Background Analysis Volume III: Groundwater  

E-print Network

Guidance for Environmental Background Analysis Volume III: Groundwater Prepared for: Naval This guidance document provides instructions for characterizing groundwater background conditions and comparing datasets representing groundwater impacted by an actual or potential chemical release to appropriate

171

Comparative analysis of nonlinear dimensionality reduction techniques for breast MRI segmentation  

SciTech Connect

Purpose: Visualization of anatomical structures using radiological imaging methods is an important tool in medicine to differentiate normal from pathological tissue and can generate large amounts of data for a radiologist to read. Integrating these large data sets is difficult and time-consuming. A new approach uses both supervised and unsupervised advanced machine learning techniques to visualize and segment radiological data. This study describes the application of a novel hybrid scheme, based on combining wavelet transform and nonlinear dimensionality reduction (NLDR) methods, to breast magnetic resonance imaging (MRI) data using three well-established NLDR techniques, namely, ISOMAP, local linear embedding (LLE), and diffusion maps (DfM), to perform a comparative performance analysis. Methods: Twenty-five breast lesion subjects were scanned using a 3T scanner. MRI sequences used were T1-weighted, T2-weighted, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging. The hybrid scheme consisted of two steps: preprocessing and postprocessing of the data. The preprocessing step was applied for B{sub 1} inhomogeneity correction, image registration, and wavelet-based image compression to match and denoise the data. In the postprocessing step, MRI parameters were considered data dimensions and the NLDR-based hybrid approach was applied to integrate the MRI parameters into a single image, termed the embedded image. This was achieved by mapping all pixel intensities from the higher dimension to a lower dimensional (embedded) space. For validation, the authors compared the hybrid NLDR with linear methods of principal component analysis (PCA) and multidimensional scaling (MDS) using synthetic data. For the clinical application, the authors used breast MRI data, comparison was performed using the postcontrast DCE MRI image and evaluating the congruence of the segmented lesions. Results: The NLDR-based hybrid approach was able to define and segment both synthetic and clinical data. In the synthetic data, the authors demonstrated the performance of the NLDR method compared with conventional linear DR methods. The NLDR approach enabled successful segmentation of the structures, whereas, in most cases, PCA and MDS failed. The NLDR approach was able to segment different breast tissue types with a high accuracy and the embedded image of the breast MRI data demonstrated fuzzy boundaries between the different types of breast tissue, i.e., fatty, glandular, and tissue with lesions (>86%). Conclusions: The proposed hybrid NLDR methods were able to segment clinical breast data with a high accuracy and construct an embedded image that visualized the contribution of different radiological parameters.

Akhbardeh, Alireza; Jacobs, Michael A. [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 (United States); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 (United States) and Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 (United States)

2012-04-15

172

Multiresolution Analysis Using Wavelet, Ridgelet, and Curvelet Transforms for Medical Image Segmentation  

PubMed Central

The experimental study presented in this paper is aimed at the development of an automatic image segmentation system for classifying region of interest (ROI) in medical images which are obtained from different medical scanners such as PET, CT, or MRI. Multiresolution analysis (MRA) using wavelet, ridgelet, and curvelet transforms has been used in the proposed segmentation system. It is particularly a challenging task to classify cancers in human organs in scanners output using shape or gray-level information; organs shape changes throw different slices in medical stack and the gray-level intensity overlap in soft tissues. Curvelet transform is a new extension of wavelet and ridgelet transforms which aims to deal with interesting phenomena occurring along curves. Curvelet transforms has been tested on medical data sets, and results are compared with those obtained from the other transforms. Tests indicate that using curvelet significantly improves the classification of abnormal tissues in the scans and reduce the surrounding noise. PMID:21960988

AlZubi, Shadi; Islam, Naveed; Abbod, Maysam

2011-01-01

173

Segmentation of Unstructured Datasets  

NASA Technical Reports Server (NTRS)

Datasets generated by computer simulations and experiments in Computational Fluid Dynamics tend to be extremely large and complex. It is difficult to visualize these datasets using standard techniques like Volume Rendering and Ray Casting. Object Segmentation provides a technique to extract and quantify regions of interest within these massive datasets. This thesis explores basic algorithms to extract coherent amorphous regions from two-dimensional and three-dimensional scalar unstructured grids. The techniques are applied to datasets from Computational Fluid Dynamics and from Finite Element Analysis.

Bhat, Smitha

1996-01-01

174

Multi-Modal Glioblastoma Segmentation: Man versus Machine  

PubMed Central

Background and Purpose Reproducible segmentation of brain tumors on magnetic resonance images is an important clinical need. This study was designed to evaluate the reliability of a novel fully automated segmentation tool for brain tumor image analysis in comparison to manually defined tumor segmentations. Methods We prospectively evaluated preoperative MR Images from 25 glioblastoma patients. Two independent expert raters performed manual segmentations. Automatic segmentations were performed using the Brain Tumor Image Analysis software (BraTumIA). In order to study the different tumor compartments, the complete tumor volume TV (enhancing part plus non-enhancing part plus necrotic core of the tumor), the TV+ (TV plus edema) and the contrast enhancing tumor volume CETV were identified. We quantified the overlap between manual and automated segmentation by calculation of diameter measurements as well as the Dice coefficients, the positive predictive values, sensitivity, relative volume error and absolute volume error. Results Comparison of automated versus manual extraction of 2-dimensional diameter measurements showed no significant difference (p?=?0.29). Comparison of automated versus manual segmentation of volumetric segmentations showed significant differences for TV+ and TV (p<0.05) but no significant differences for CETV (p>0.05) with regard to the Dice overlap coefficients. Spearman's rank correlation coefficients (?) of TV+, TV and CETV showed highly significant correlations between automatic and manual segmentations. Tumor localization did not influence the accuracy of segmentation. Conclusions In summary, we demonstrated that BraTumIA supports radiologists and clinicians by providing accurate measures of cross-sectional diameter-based tumor extensions. The automated volume measurements were comparable to manual tumor delineation for CETV tumor volumes, and outperformed inter-rater variability for overlap and sensitivity. PMID:24804720

Pica, Alessia; Schucht, Philippe; Beck, Jürgen; Verma, Rajeev Kumar; Slotboom, Johannes; Reyes, Mauricio; Wiest, Roland

2014-01-01

175

Segmentation of 2-D and 3-D objects from MRI volume data using constrained elastic deformations of flexible Fourier contour and surface models.  

PubMed

This paper describes a new model-based segmentation technique combining desirable properties of physical models (snakes), shape representation by Fourier parametrization, and modelling of natural shape variability. Flexible parametric shape models are represented by a parameter vector describing the mean contour and by a set of eigenmodes of the parameters characterizing the shape variation. Usually the segmentation process is divided into an initial placement of the mean model and an elastic deformation restricted to the model variability. This, however leads to a separation of biological variation due to a global similarity transform from small-scale shape changes originating from elastic deformations of the normalized model contours only. The performance can be considerably improved by building shape models normalized with respect to a small set of stable landmarks (AC-PC in our application) and by explaining the remaining variability among a series of images with the model flexibility. This way the image interpretation is solved by a new coarse-to-fine segmentation procedure based on the set of deformation eigenmodes, making a separate initialization step unnecessary. Although straightforward, the extension to 3-D is severely impeded by difficulties arising during the generation of a proper surface parametrization for arbitrary objects with spherical topology. We apply a newly developed surface parametrization which achieves a uniform mapping between object surface and parameter space. The 3-D procedure is demonstrated by segmenting deep structures of the human brain from MR volume data. PMID:9873919

Székely, G; Kelemen, A; Brechbühler, C; Gerig, G

1996-03-01

176

Dense nuclei segmentation based on graph cut and convexity-concavity analysis.  

PubMed

With the rapid advancement of 3D confocal imaging technology, more and more 3D cellular images will be available. However, robust and automatic extraction of nuclei shape may be hindered by a highly cluttered environment, as for example, in fly eye tissues. In this paper, we present a novel and efficient nuclei segmentation algorithm based on the combination of graph cut and convex shape assumption. The main characteristic of the algorithm is that it segments nuclei foreground using a graph-cut algorithm with our proposed new initialization method and splits overlapping or touching cell nuclei by simple convexity and concavity analysis. Experimental results show that the proposed algorithm can segment complicated nuclei clumps effectively in our fluorescent fruit fly eye images. Evaluation on a public hand-labelled 2D benchmark demonstrates substantial quantitative improvement over other methods. For example, the proposed method achieves a 3.2 Hausdorff distance decrease and a 1.8 decrease in the merged nuclei error per slice. PMID:24237576

Qi, J

2014-01-01

177

Local multifractal detrended fluctuation analysis for non-stationary image's texture segmentation  

NASA Astrophysics Data System (ADS)

Feature extraction plays a great important role in image processing and pattern recognition. As a power tool, multifractal theory is recently employed for this job. However, traditional multifractal methods are proposed to analyze the objects with stationary measure and cannot for non-stationary measure. The works of this paper is twofold. First, the definition of stationary image and 2D image feature detection methods are proposed. Second, a novel feature extraction scheme for non-stationary image is proposed by local multifractal detrended fluctuation analysis (Local MF-DFA), which is based on 2D MF-DFA. A set of new multifractal descriptors, called local generalized Hurst exponent (Lhq) is defined to characterize the local scaling properties of textures. To test the proposed method, both the novel texture descriptor and other two multifractal indicators, namely, local Hölder coefficients based on capacity measure and multifractal dimension Dq based on multifractal differential box-counting (MDBC) method, are compared in segmentation experiments. The first experiment indicates that the segmentation results obtained by the proposed Lhq are better than the MDBC-based Dq slightly and superior to the local Hölder coefficients significantly. The results in the second experiment demonstrate that the Lhq can distinguish the texture images more effectively and provide more robust segmentations than the MDBC-based Dq significantly.

Wang, Fang; Li, Zong-shou; Li, Jin-wei

2014-12-01

178

A marked point process of rectangles and segments for automatic analysis of digital elevation models.  

PubMed

This work presents a framework for automatic feature extraction from images using stochastic geometry. Features in images are modeled as realizations of a spatial point process of geometrical shapes. This framework allows the incorporation of a priori knowledge on the spatial repartition of features. More specifically, we present a model based on the superposition of a process of segments and a process of rectangles. The former is dedicated to the detection of linear networks of discontinuities, while the latter aims at segmenting homogeneous areas. An energy is defined, favoring connections of segments, alignments of rectangles, as well as a relevant interaction between both types of objects. The estimation is performed by minimizing the energy using a simulated annealing algorithm. The proposed model is applied to the analysis of Digital Elevation Models (DEMs). These images are raster data representing the altimetry of a dense urban area. We present results on real data provided by the IGN (French National Geographic Institute) consisting in low quality DEMs of various types. PMID:18000328

Ortner, Mathias; Descombe, Xavier; Zerubia, Josiane

2008-01-01

179

Improved disparity map analysis through the fusion of monocular image segmentations  

NASA Technical Reports Server (NTRS)

The focus is to examine how estimates of three dimensional scene structure, as encoded in a scene disparity map, can be improved by the analysis of the original monocular imagery. The utilization of surface illumination information is provided by the segmentation of the monocular image into fine surface patches of nearly homogeneous intensity to remove mismatches generated during stereo matching. These patches are used to guide a statistical analysis of the disparity map based on the assumption that such patches correspond closely with physical surfaces in the scene. Such a technique is quite independent of whether the initial disparity map was generated by automated area-based or feature-based stereo matching. Stereo analysis results are presented on a complex urban scene containing various man-made and natural features. This scene contains a variety of problems including low building height with respect to the stereo baseline, buildings and roads in complex terrain, and highly textured buildings and terrain. The improvements are demonstrated due to monocular fusion with a set of different region-based image segmentations. The generality of this approach to stereo analysis and its utility in the development of general three dimensional scene interpretation systems are also discussed.

Perlant, Frederic P.; Mckeown, David M.

1991-01-01

180

Information architecture. Volume 2, Part 1: Baseline analysis summary  

SciTech Connect

The Department of Energy (DOE) Information Architecture, Volume 2, Baseline Analysis, is a collaborative and logical next-step effort in the processes required to produce a Departmentwide information architecture. The baseline analysis serves a diverse audience of program management and technical personnel and provides an organized way to examine the Department`s existing or de facto information architecture. A companion document to Volume 1, The Foundations, it furnishes the rationale for establishing a Departmentwide information architecture. This volume, consisting of the Baseline Analysis Summary (part 1), Baseline Analysis (part 2), and Reference Data (part 3), is of interest to readers who wish to understand how the Department`s current information architecture technologies are employed. The analysis identifies how and where current technologies support business areas, programs, sites, and corporate systems.

NONE

1996-12-01

181

Computer-aided measurement of liver volumes in CT by means of geodesic active contour segmentation coupled with level-set algorithms  

SciTech Connect

Purpose: Computerized liver extraction from hepatic CT images is challenging because the liver often abuts other organs of a similar density. The purpose of this study was to develop a computer-aided measurement of liver volumes in hepatic CT. Methods: The authors developed a computerized liver extraction scheme based on geodesic active contour segmentation coupled with level-set contour evolution. First, an anisotropic diffusion filter was applied to portal-venous-phase CT images for noise reduction while preserving the liver structure, followed by a scale-specific gradient magnitude filter to enhance the liver boundaries. Then, a nonlinear grayscale converter enhanced the contrast of the liver parenchyma. By using the liver-parenchyma-enhanced image as a speed function, a fast-marching level-set algorithm generated an initial contour that roughly estimated the liver shape. A geodesic active contour segmentation algorithm coupled with level-set contour evolution refined the initial contour to define the liver boundaries more precisely. The liver volume was then calculated using these refined boundaries. Hepatic CT scans of 15 prospective liver donors were obtained under a liver transplant protocol with a multidetector CT system. The liver volumes extracted by the computerized scheme were compared to those traced manually by a radiologist, used as ''gold standard.''Results: The mean liver volume obtained with our scheme was 1504 cc, whereas the mean gold standard manual volume was 1457 cc, resulting in a mean absolute difference of 105 cc (7.2%). The computer-estimated liver volumetrics agreed excellently with the gold-standard manual volumetrics (intraclass correlation coefficient was 0.95) with no statistically significant difference (F=0.77; p(F{<=}f)=0.32). The average accuracy, sensitivity, specificity, and percent volume error were 98.4%, 91.1%, 99.1%, and 7.2%, respectively. Computerized CT liver volumetry would require substantially less completion time (compared to an average of 39 min per case by manual segmentation). Conclusions: The computerized liver extraction scheme provides an efficient and accurate way of measuring liver volumes in CT.

Suzuki, Kenji; Kohlbrenner, Ryan; Epstein, Mark L.; Obajuluwa, Ademola M.; Xu Jianwu; Hori, Masatoshi [Department of Radiology, University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637 (United States)

2010-05-15

182

Texture analysis improves level set segmentation of the anterior abdominal wall  

SciTech Connect

Purpose: The treatment of ventral hernias (VH) has been a challenging problem for medical care. Repair of these hernias is fraught with failure; recurrence rates ranging from 24% to 43% have been reported, even with the use of biocompatible mesh. Currently, computed tomography (CT) is used to guide intervention through expert, but qualitative, clinical judgments, notably, quantitative metrics based on image-processing are not used. The authors propose that image segmentation methods to capture the three-dimensional structure of the abdominal wall and its abnormalities will provide a foundation on which to measure geometric properties of hernias and surrounding tissues and, therefore, to optimize intervention.Methods: In this study with 20 clinically acquired CT scans on postoperative patients, the authors demonstrated a novel approach to geometric classification of the abdominal. The authors’ approach uses a texture analysis based on Gabor filters to extract feature vectors and follows a fuzzy c-means clustering method to estimate voxelwise probability memberships for eight clusters. The memberships estimated from the texture analysis are helpful to identify anatomical structures with inhomogeneous intensities. The membership was used to guide the level set evolution, as well as to derive an initial start close to the abdominal wall.Results: Segmentation results on abdominal walls were both quantitatively and qualitatively validated with surface errors based on manually labeled ground truth. Using texture, mean surface errors for the outer surface of the abdominal wall were less than 2 mm, with 91% of the outer surface less than 5 mm away from the manual tracings; errors were significantly greater (2–5 mm) for methods that did not use the texture.Conclusions: The authors’ approach establishes a baseline for characterizing the abdominal wall for improving VH care. Inherent texture patterns in CT scans are helpful to the tissue classification, and texture analysis can improve the level set segmentation around the abdominal region.

Xu, Zhoubing [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 (United States); Allen, Wade M. [Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States); Baucom, Rebeccah B.; Poulose, Benjamin K. [General Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37235 (United States)] [General Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37235 (United States); Landman, Bennett A. [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)

2013-12-15

183

Segmentation and Morphometric Analysis of Cells from Fluorescence Microscopy Images of Cytoskeletons  

PubMed Central

We developed a method to reconstruct cell geometry from confocal fluorescence microscopy images of the cytoskeleton. In the method, region growing was implemented twice. First, it was applied to the extracellular regions to differentiate them from intracellular noncytoskeletal regions, which both appear black in fluorescence microscopy imagery, and then to cell regions for cell identification. Analysis of morphological parameters revealed significant changes in cell shape associated with cytoskeleton disruption, which offered insight into the mechanical role of the cytoskeleton in maintaining cell shape. The proposed segmentation method is promising for investigations on cell morphological changes with respect to internal cytoskeletal structures. PMID:23762186

Ujihara, Yoshihiro; Nakamura, Masanori; Miyazaki, Hiroshi; Wada, Shigeo

2013-01-01

184

3-D segmentation of the rim and cup in spectral-domain optical coherence tomography volumes of the optic nerve head  

NASA Astrophysics Data System (ADS)

Glaucoma is a group of diseases which can cause vision loss and blindness due to gradual damage to the optic nerve. The ratio of the optic disc cup to the optic disc is an important structural indicator for assessing the presence of glaucoma. The purpose of this study is to develop and evaluate a method which can segment the optic disc cup and neuroretinal rim in spectral-domain OCT scans centered on the optic nerve head. Our method starts by segmenting 3 intraretinal surfaces using a fast multiscale 3-D graph search method. Based on one of the segmented surfaces, the retina of the OCT volume is flattened to have a consistent shape across scans and patients. Selected features derived from OCT voxel intensities and intraretinal surfaces were used to train a k-NN classifier that can determine which A-scans in the OCT volume belong to the background, optic disc cup and neuroretinal rim. Through 3-fold cross validation with a training set of 20 optic nerve head-centered OCT scans (10 right eye scans and 10 left eye scans from 10 glaucoma patients) and a testing set of 10 OCT scans (5 right eye scans and 5 left eye scans from 5 different glaucoma patients), segmentation results of the optic disc cup and rim for all 30 OCT scans were obtained. The average unsigned errors of the optic disc cup and rim were 1.155 +/- 1.391 pixels (0.035 +/- 0.042 mm) and 1.295 +/- 0.816 pixels (0.039 +/- 0.024 mm), respectively.

Lee, Kyungmoo; Niemeijer, Meindert; Garvin, Mona K.; Kwon, Young H.; Sonka, Milan; Abràmoff, Michael D.

2009-02-01

185

Patents Citing Fionn Murtagh's Work on: Factor analysis/retail data mining segmentation in a data mining system  

E-print Network

system that analyzes customer transaction data using Factor Analysis/Retail Data Mining Segmentation Bisgaard- Bohr and Scott W. Cunningham, and entitled "DATA MODEL FOR ANALYSIS OF RETAIL TRANSACTIONS USING 1 Patents Citing Fionn Murtagh's Work on: Clustering (1) Factor analysis/retail data mining

Murtagh, Fionn

186

A posteriori error analysis for a finite volume method  

E-print Network

posteriori analysis for an elliptic problem Let U be a Galerkin finite element approximation for - · au + b of nuclear fuel rods, electrical impedance tomography · Pose well known challenges for accurate numericalA posteriori error analysis for a "cut-cell" finite volume method D. Estep, M. Pernice, S. Tavener

Tavener, Simon

187

Three-Dimensional Blood Vessel Segmentation and Centerline Extraction based on Two-Dimensional Cross-Section Analysis.  

PubMed

The segmentation of tubular tree structures like vessel systems in volumetric datasets is of vital interest for many medical applications. In this paper we present a novel, semi-automatic method for blood vessel segmentation and centerline extraction, by tracking the blood vessel tree from a user-initiated seed point to the ends of the blood vessel tree. The novelty of our method is in performing only two-dimensional cross-section analysis for segmentation of the connected blood vessels. The cross-section analysis is done by our novel single-scale or multi-scale circle enhancement filter, used at the blood vessel trunk or bifurcation, respectively. The method was validated for both synthetic and medical images. Our validation has shown that the cross-sectional centerline error for our method is below 0.8 pixels and the Dice coefficient for our segmentation is 80% ± 2.7%. On combining our method with an optional active contour post-processing, the Dice coefficient for the resulting segmentation is found to be 94% ± 2.4%. Furthermore, by restricting the image analysis to the regions of interest and converting most of the three-dimensional calculations to two-dimensional calculations, the processing was found to be more than 18 times faster than Frangi vesselness with thinning, 8 times faster than user-initiated active contour segmentation with thinning and 7 times faster than our previous method. PMID:25398332

Kumar, Rahul Prasanna; Albregtsen, Fritz; Reimers, Martin; Edwin, Bjørn; Langø, Thomas; Elle, Ole Jakob

2014-11-15

188

Laser power conversion system analysis, volume 1  

NASA Technical Reports Server (NTRS)

The orbit-to-orbit laser energy conversion system analysis established a mission model of satellites with various orbital parameters and average electrical power requirements ranging from 1 to 300 kW. The system analysis evaluated various conversion techniques, power system deployment parameters, power system electrical supplies and other critical supplies and other critical subsystems relative to various combinations of the mission model. The analysis show that the laser power system would not be competitive with current satellite power systems from weight, cost and development risk standpoints.

Jones, W. S.; Morgan, L. L.; Forsyth, J. B.; Skratt, J. P.

1979-01-01

189

Laser power conversion system analysis, volume 2  

NASA Technical Reports Server (NTRS)

The orbit-to-ground laser power conversion system analysis investigated the feasibility and cost effectiveness of converting solar energy into laser energy in space, and transmitting the laser energy to earth for conversion to electrical energy. The analysis included space laser systems with electrical outputs on the ground ranging from 100 to 10,000 MW. The space laser power system was shown to be feasible and a viable alternate to the microwave solar power satellite. The narrow laser beam provides many options and alternatives not attainable with a microwave beam.

Jones, W. S.; Morgan, L. L.; Forsyth, J. B.; Skratt, J. P.

1979-01-01

190

MRI-Assessment of Tumor Perfusion and 3D Segmented Volume at Baseline, During Treatment, and at Tumor Progression in Children with Newly Diagnosed Diffuse Intrinsic Pontine Glioma  

PubMed Central

Background and Purpose Diffuse Intrinsic Pontine Glioma (DIPG) is among the most devastating brain tumors in children, necessitating the development of novel treatment strategies and advanced imaging markers such as perfusion to adequately monitor clinical trials. This study investigated tumor perfusion and 3D segmented tumor volume as predictive markers for outcome in children with newly diagnosed DIPG. Methods Imaging data were assessed at baseline, during, and after radiation therapy (RT), and every other month thereafter till progression, for 35 patients with newly diagnosed DIPG (age 2–16 years) enrolled on the phase I clinical study, NCT00472017. Patients were treated with conformal RT and vandetanib, a vascular endothelial growth factor receptor 2 inhibitor. Results Tumor perfusion increased and tumor volume decreased during combined RT and vandetanib therapy. These changes slowly diminished in follow-up scans till tumor progression. However, increased tumor perfusion and decreased tumor volume during combined therapy were associated with longer PFS. Apart from a longer OS for patients who showed elevated tumor perfusion after RT, there was no association for tumor volume and other perfusion variables with OS. Conclusion Our results suggest that tumor perfusion may be a useful predictive marker for the assessment of treatment response and tumor progression in children with DIPG treated with both RT and vandetanib. The assessment of tumor perfusion yields valuable information about tumor microvascular status and its response to therapy, which may to help better understand the biology of DIPGs and monitor novel treatment strategies in future clinical trials. PMID:23436052

Sedlacik, J.; Winchell, A.; Kocak, M.; Loeffler, R.B.; Broniscer, A.; Hillenbrand, C.M.

2014-01-01

191

Theoretical analysis of segmented Wolter/LSM X-ray telescope systems  

NASA Technical Reports Server (NTRS)

The Segmented Wolter I/LSM X-ray Telescope, which consists of a Wolter I Telescope with a tilted, off-axis convex spherical Layered Synthetic Microstructure (LSM) optics placed near the primary focus to accommodate multiple off-axis detectors, has been analyzed. The Skylab ATM Experiment S056 Wolter I telescope and the Stanford/MSFC nested Wolter-Schwarzschild x-ray telescope have been considered as the primary optics. A ray trace analysis has been performed to calculate the RMS blur circle radius, point spread function (PSF), the meridional and sagittal line functions (LST), and the full width half maximum (PWHM) of the PSF to study the spatial resolution of the system. The effects on resolution of defocussing the image plane, tilting and decentrating of the multilayer (LSM) optics have also been investigated to give the mounting and alignment tolerances of the LSM optic. Comparison has been made between the performance of the segmented Wolter/LSM optical system and that of the Spectral Slicing X-ray Telescope (SSXRT) systems.

Shealy, D. L.; Chao, S. H.

1986-01-01

192

Evolutionary analysis of the segment from helix 3 through helix 5 in vertebrate progesterone receptors.  

PubMed

The interaction between helix 3 and helix 5 in the human mineralocorticoid receptor [MR], progesterone receptor [PR] and glucocorticoid receptor [GR] influences their response to steroids. For the human PR, mutations at Gly-722 on helix 3 and Met-759 on helix 5 alter responses to progesterone. We analyzed the evolution of these two sites and the rest of a 59 residue segment containing helices 3, 4 and 5 in vertebrate PRs and found that a glycine corresponding to Gly-722 on helix 3 in human PR first appears in platypus, a monotreme. In lamprey, skates, fish, amphibians and birds, cysteine is found at this position in helix 3. This suggests that the cysteine to glycine replacement in helix 3 in the PR was important in the evolution of mammals. Interestingly, our analysis of the rest of the 59 residue segment finds 100% sequence conservation in almost all mammal PRs, substantial conservation in reptile and amphibian PRs and divergence of land vertebrate PR sequences from the fish PR sequences. The differences between fish and land vertebrate PRs may be important in the evolution of different biological progestins in fish and mammalian PR, as well as differences in susceptibility to environmental chemicals that disrupt PR-mediated physiology. PMID:22575083

Baker, Michael E; Uh, Kayla Y

2012-10-01

193

A Comparison of Amplitude-Based and Phase-Based Positron Emission Tomography Gating Algorithms for Segmentation of Internal Target Volumes of Tumors Subject to Respiratory Motion  

SciTech Connect

Purpose: To quantitatively compare the accuracy of tumor volume segmentation in amplitude-based and phase-based respiratory gating algorithms in respiratory-correlated positron emission tomography (PET). Methods and Materials: List-mode fluorodeoxyglucose-PET data was acquired for 10 patients with a total of 12 fluorodeoxyglucose-avid tumors and 9 lymph nodes. Additionally, a phantom experiment was performed in which 4 plastic butyrate spheres with inner diameters ranging from 1 to 4 cm were imaged as they underwent 1-dimensional motion based on 2 measured patient breathing trajectories. PET list-mode data were gated into 8 bins using 2 amplitude-based (equal amplitude bins [A1] and equal counts per bin [A2]) and 2 temporal phase-based gating algorithms. Gated images were segmented using a commercially available gradient-based technique and a fixed 40% threshold of maximum uptake. Internal target volumes (ITVs) were generated by taking the union of all 8 contours per gated image. Segmented phantom ITVs were compared with their respective ground-truth ITVs, defined as the volume subtended by the tumor model positions covering 99% of breathing amplitude. Superior-inferior distances between sphere centroids in the end-inhale and end-exhale phases were also calculated. Results: Tumor ITVs from amplitude-based methods were significantly larger than those from temporal-based techniques (P=.002). For lymph nodes, A2 resulted in ITVs that were significantly larger than either of the temporal-based techniques (P<.0323). A1 produced the largest and most accurate ITVs for spheres with diameters of ?2 cm (P=.002). No significant difference was shown between algorithms in the 1-cm sphere data set. For phantom spheres, amplitude-based methods recovered an average of 9.5% more motion displacement than temporal-based methods under regular breathing conditions and an average of 45.7% more in the presence of baseline drift (P<.001). Conclusions: Target volumes in images generated from amplitude-based gating are larger and more accurate, at levels that are potentially clinically significant, compared with those from temporal phase-based gating.

Jani, Shyam S., E-mail: sjani@mednet.ucla.edu [Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, California (United States); Robinson, Clifford G. [Department of Radiation Oncology, Siteman Cancer Center, Washington University in St Louis, St Louis, Missouri (United States); Dahlbom, Magnus [Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California (United States); White, Benjamin M.; Thomas, David H.; Gaudio, Sergio; Low, Daniel A.; Lamb, James M. [Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, California (United States)

2013-11-01

194

Final safety analysis report for the Galileo Mission: Volume 2, Book 2: Accident model document: Appendices  

SciTech Connect

This section of the Accident Model Document (AMD) presents the appendices which describe the various analyses that have been conducted for use in the Galileo Final Safety Analysis Report II, Volume II. Included in these appendices are the approaches, techniques, conditions and assumptions used in the development of the analytical models plus the detailed results of the analyses. Also included in these appendices are summaries of the accidents and their associated probabilities and environment models taken from the Shuttle Data Book (NSTS-08116), plus summaries of the several segments of the recent GPHS safety test program. The information presented in these appendices is used in Section 3.0 of the AMD to develop the Failure/Abort Sequence Trees (FASTs) and to determine the fuel releases (source terms) resulting from the potential Space Shuttle/IUS accidents throughout the missions.

Not Available

1988-12-15

195

Twitter Volume Spikes: Analysis and Application in Stock Trading  

E-print Network

over a half year's stock market data indicates that it achieves on average 8.6% gain in 27 trading daysTwitter Volume Spikes: Analysis and Application in Stock Trading Yuexin Mao University bing@engr.uconn.edu ABSTRACT Stock is a popular topic in Twitter. The number of tweets concern- ing

Wang, Bing

196

Cerebrospinal fluid volume analysis for hydrocephalus diagnosis and clinical research  

E-print Network

with various types of hydrocephalus in [3, 4], whereas it is limited to normal pressure hydrocephalus, iCerebrospinal fluid volume analysis for hydrocephalus diagnosis and clinical research Alain Lebreta in range [0.63, 4.61] for hydrocephalus patients. This indicates that a robust distinction between

Paris-Sud XI, Université de

197

Cost-Volume-Profit Analysis Adjusted for Learning  

Microsoft Academic Search

A model is developed for cost-volume-profit analysis which incorporates a nonlinear cost function to express the effects of employee learning. Sensitivity analysis is applied to the model to assess the impact of estimation errors in the learning rate and steady-state production time on estimated profit and break-even quantities. The paper also examines the effects on the model of (1) alternative

E. V. McIntyre

1977-01-01

198

Spectral analysis program. Volume 1: User's guide  

NASA Technical Reports Server (NTRS)

The spectral analysis program (SAP) was developed to provide the Manned Spacecraft Center with the capability of computing the power spectrum of a phase or frequency modulated high frequency carrier wave. Previous power spectrum computational techniques were restricted to relatively simple modulating signals because of excessive computational time, even on a high speed digital computer. The present technique uses the recently developed extended fast Fourier transform and represents a generalized approach for simple and complex modulating signals. The present technique is especially convenient for implementation of a variety of low-pass filters for the modulating signal and bandpass filters for the modulated signal.

Hayden, W. L.

1972-01-01

199

SD-OCT to differentiate traumatic submacular hemorrhage types using automatic three-dimensional segmentation analysis.  

PubMed

Traumatic submacular hemorrhage may present with significant decrease in vision and may have varying outcomes. Following injury, the hemorrhage can collect either between the neurosensory retina and retinal pigment epithelium (RPE) or below the RPE. This differentiation may be important to prognosticate and to guide treatment. In two patients with post-traumatic submacular hemorrhage, Cirrius spectral domain high-definition optical coherence tomography (OCT) (Carl Zeiss Meditec, Dublin, CA) was used to differentiate traumatic submacular hemorrhage types using automation three-dimensional segmentation analysis. Based on the OCT findings, the patient with sub-RPE bleed was subjected to pneumatic displacement. En face C-scan imaging just below the RPE allowed for the diagnosis of the exact location of choroidal rupture that was masked due to hemorrhage. PMID:21366180

Sampangi, Raju; Chandrakumar, H V; Somashekar, Sandhya E; Joshi, Gauri R; Ganesh, Sri

2011-01-01

200

Local label learning (LLL) for subcortical structure segmentation: application to hippocampus segmentation.  

PubMed

Automatic and reliable segmentation of subcortical structures is an important but difficult task in quantitative brain image analysis. Multi-atlas based segmentation methods have attracted great interest due to their promising performance. Under the multi-atlas based segmentation framework, using deformation fields generated for registering atlas images onto a target image to be segmented, labels of the atlases are first propagated to the target image space and then fused to get the target image segmentation based on a label fusion strategy. While many label fusion strategies have been developed, most of these methods adopt predefined weighting models that are not necessarily optimal. In this study, we propose a novel local label learning strategy to estimate the target image's segmentation label using statistical machine learning techniques. In particular, we use a L1-regularized support vector machine (SVM) with a k nearest neighbor (kNN) based training sample selection strategy to learn a classifier for each of the target image voxel from its neighboring voxels in the atlases based on both image intensity and texture features. Our method has produced segmentation results consistently better than state-of-the-art label fusion methods in validation experiments on hippocampal segmentation of over 100 MR images obtained from publicly available and in-house datasets. Volumetric analysis has also demonstrated the capability of our method in detecting hippocampal volume changes due to Alzheimer's disease. PMID:24151008

Hao, Yongfu; Wang, Tianyao; Zhang, Xinqing; Duan, Yunyun; Yu, Chunshui; Jiang, Tianzi; Fan, Yong

2014-06-01

201

Semisupervised segmentation of MRI stroke studies  

NASA Astrophysics Data System (ADS)

Fast, accurate, and reproducible image segmentation is vital to the diagnosis, treatment, and evaluation of many medical situations. We present development and application of a semi-supervised method for segmenting normal and abnormal brain tissues from magnetic resonance images (MRI) of stroke patients. The method does not require manual drawing of the tissue boundaries. It is therefore faster and more reproducible than conventional methods. The steps of the new method are as follows: (1) T2- and T1-weighted MR images are co-registered using a head and hat approach. (2) Intracranial brain volume is segmented from the skull, scalp, and background using a multi-resolution edge tracking algorithm. (3) Additive noise is suppressed (image is restored) using a non-linear edge-preserving filter which preserves partial volume information on average. (4) Image nonuniformities are corrected using a modified lowpass filtering approach. (5) The resulting images are segmented using a self organizing data analysis technique which is similar in principle to the K-means clustering but includes a set of additional heuristic merging and splitting procedures to generate a meaningful segmentation. (6) Segmented regions are labeled white matter, gray matter, CSF, partial volumes of normal tissues, zones of stroke, or partial volumes between stroke and normal tissues. (7) Previous steps are repeated for each slice of the brain and the volume of each tissue type is estimated from the results. Details and significance of each step are explained. Experimental results using a simulation, a phantom, and selected clinical cases are presented.

Soltanian-Zadeh, Hamid; Windham, Joe P.; Robbins, Linda

1997-04-01

202

Multi-atlas multi-shape segmentation of fetal brain MRI for volumetric and morphometric analysis of ventriculomegaly.  

PubMed

The recent development of motion robust super-resolution fetal brain MRI holds out the potential for dramatic new advances in volumetric and morphometric analysis. Volumetric analysis based on volumetric and morphometric biomarkers of the developing fetal brain must include segmentation. Automatic segmentation of fetal brain MRI is challenging, however, due to the highly variable size and shape of the developing brain; possible structural abnormalities; and the relatively poor resolution of fetal MRI scans. To overcome these limitations, we present a novel, constrained, multi-atlas, multi-shape automatic segmentation method that specifically addresses the challenge of segmenting multiple structures with similar intensity values in subjects with strong anatomic variability. Accordingly, we have applied this method to shape segmentation of normal, dilated, or fused lateral ventricles for quantitative analysis of ventriculomegaly (VM), which is a pivotal finding in the earliest stages of fetal brain development, and warrants further investigation. Utilizing these innovative techniques, we introduce novel volumetric and morphometric biomarkers of VM comparing these values to those that are generated by standard methods of VM analysis, i.e., by measuring the ventricular atrial diameter (AD) on manually selected sections of 2D ultrasound or 2D MRI. To this end, we studied 25 normal and abnormal fetuses in the gestation age (GA) range of 19 to 39 weeks (mean=28.26, stdev=6.56). This heterogeneous dataset was essentially used to 1) validate our segmentation method for normal and abnormal ventricles; and 2) show that the proposed biomarkers may provide improved detection of VM as compared to the AD measurement. PMID:22500924

Gholipour, Ali; Akhondi-Asl, Alireza; Estroff, Judy A; Warfield, Simon K

2012-04-15

203

Interactive 3D Analysis of Blood Vessel Trees and Collateral Vessel Volumes in Magnetic Resonance Angiograms in the Mouse Ischemic Hindlimb Model.  

PubMed

The quantitative analysis of blood vessel volumes from magnetic resonance angiograms (MRA) or ?CT images is difficult and time-consuming. This fact, when combined with a study that involves multiple scans of multiple subjects, can represent a significant portion of research time. In order to enhance analysis options and to provide an automated and fast analysis method, we developed a software plugin for the ImageJ and Fiji image processing frameworks that enables the quick and reproducible volume quantification of blood vessel segments. The novel plugin named Volume Calculator (VolCal), accepts any binary (thresholded) image and produces a three-dimensional schematic representation of the vasculature that can be directly manipulated by the investigator. Using MRAs of the mouse hindlimb ischemia model, we demonstrate quick and reproducible blood vessel volume calculations with 95 - 98% accuracy. In clinical settings this software may enhance image interpretation and the speed of data analysis and thus enhance intervention decisions for example in peripheral vascular disease or aneurysms. In summary, we provide a novel, fast and interactive quantification of blood vessel volumes for single blood vessels or sets of vessel segments with particular focus on collateral formation after an ischemic insult. PMID:24563682

Marks, Peter C; Preda, Marilena; Henderson, Terry; Liaw, Lucy; Lindner, Volkhard; Friesel, Robert E; Pinz, Ilka M

2013-10-31

204

Interactive 3D Analysis of Blood Vessel Trees and Collateral Vessel Volumes in Magnetic Resonance Angiograms in the Mouse Ischemic Hindlimb Model  

PubMed Central

The quantitative analysis of blood vessel volumes from magnetic resonance angiograms (MRA) or ?CT images is difficult and time-consuming. This fact, when combined with a study that involves multiple scans of multiple subjects, can represent a significant portion of research time. In order to enhance analysis options and to provide an automated and fast analysis method, we developed a software plugin for the ImageJ and Fiji image processing frameworks that enables the quick and reproducible volume quantification of blood vessel segments. The novel plugin named Volume Calculator (VolCal), accepts any binary (thresholded) image and produces a three-dimensional schematic representation of the vasculature that can be directly manipulated by the investigator. Using MRAs of the mouse hindlimb ischemia model, we demonstrate quick and reproducible blood vessel volume calculations with 95 – 98% accuracy. In clinical settings this software may enhance image interpretation and the speed of data analysis and thus enhance intervention decisions for example in peripheral vascular disease or aneurysms. In summary, we provide a novel, fast and interactive quantification of blood vessel volumes for single blood vessels or sets of vessel segments with particular focus on collateral formation after an ischemic insult. PMID:24563682

Marks, Peter C.; Preda, Marilena; Henderson, Terry; Liaw, Lucy; Lindner, Volkhard; Friesel, Robert E.; Pinz, Ilka M.

2014-01-01

205

Shared genomic segment analysis: the power to find rare disease variants.  

PubMed

Shared genomic segment (SGS) analysis uses dense single nucleotide polymorphism genotyping in high-risk (HR) pedigrees to identify regions of sharing between cases. Here, we illustrate the power of SGS to identify dominant rare risk variants. Using simulated pedigrees, we consider 12 disease models based on disease prevalence, minor allele frequency and penetrance to represent disease loci that explain 0.2-99.8% of total disease risk. Pedigrees were required to contain ? 15 meioses between all cases and to be HR based on significant excess of disease (P < 0.001 or P < 0.00001). Across these scenarios, the power for a single pedigree ranged widely. Nonetheless, fewer than 10 pedigrees were sufficient for excellent power in the majority of models. Power increased with the risk attributable to the disease locus, penetrance and the excess of disease in the pedigree. Sharing allowing for one sporadic case was uniformly more powerful than sharing using all cases. Furthermore, an SGS analysis using a large attenuated familial adenomatous polyposis pedigree identified a 1.96 Mb region containing the known causal APC gene with genome-wide significance. SGS is a powerful method for detecting rare variants and a valuable complement to genome-wide association studies and linkage analysis. PMID:22989048

Knight, Stacey; Abo, Ryan P; Abel, Haley J; Neklason, Deborah W; Tuohy, Therese M; Burt, Randall W; Thomas, Alun; Camp, Nicola J

2012-11-01

206

Segmental analysis of amphetamines in hair using a sensitive UHPLC-MS/MS method.  

PubMed

A sensitive and robust ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxy methamphetamine in hair samples. Segmented hair (10?mg) was incubated in 2M sodium hydroxide (80°C, 10?min) before liquid-liquid extraction with isooctane followed by centrifugation and evaporation of the organic phase to dryness. The residue was reconstituted in methanol:formate buffer pH 3 (20:80). The total run time was 4?min and after optimization of UHPLC-MS/MS-parameters validation included selectivity, matrix effects, recovery, process efficiency, calibration model and range, lower limit of quantification, precision and bias. The calibration curve ranged from 0.02 to 12.5?ng/mg, and the recovery was between 62 and 83%. During validation the bias was less than ±7% and the imprecision was less than 5% for all analytes. In routine analysis, fortified control samples demonstrated an imprecision <13% and control samples made from authentic hair demonstrated an imprecision <26%. The method was applied to samples from a controlled study of amphetamine intake as well as forensic hair samples previously analyzed with an ultra high performance liquid chromatography time of flight mass spectrometry (UHPLC-TOF-MS) screening method. The proposed method was suitable for quantification of these drugs in forensic cases including violent crimes, autopsy cases, drug testing and re-granting of driving licences. This study also demonstrated that if hair samples are divided into several short segments, the time point for intake of a small dose of amphetamine can be estimated, which might be useful when drug facilitated crimes are investigated. PMID:24817045

Jakobsson, Gerd; Kronstrand, Robert

2014-06-01

207

Automated condition-invariable neurite segmentation and synapse classification using textural analysis-based machine-learning algorithms  

PubMed Central

High-resolution live-cell imaging studies of neuronal structure and function are characterized by large variability in image acquisition conditions due to background and sample variations as well as low signal-to-noise ratio. The lack of automated image analysis tools that can be generalized for varying image acquisition conditions represents one of the main challenges in the field of biomedical image analysis. Specifically, segmentation of the axonal/dendritic arborizations in brightfield or fluorescence imaging studies is extremely labor-intensive and still performed mostly manually. Here we describe a fully automated machine-learning approach based on textural analysis algorithms for segmenting neuronal arborizations in high-resolution brightfield images of live cultured neurons. We compare performance of our algorithm to manual segmentation and show that it combines 90% accuracy, with similarly high levels of specificity and sensitivity. Moreover, the algorithm maintains high performance levels under a wide range of image acquisition conditions indicating that it is largely condition-invariable. We further describe an application of this algorithm to fully automated synapse localization and classification in fluorescence imaging studies based on synaptic activity. Textural analysis-based machine-learning approach thus offers a high performance condition-invariable tool for automated neurite segmentation. PMID:23261652

Kandaswamy, Umasankar; Rotman, Ziv; Watt, Dana; Schillebeeckx, Ian; Cavalli, Valeria; Klyachko, Vitaly

2013-01-01

208

Computerized Detection of Masses in Digitized Mammograms Using Single-Image Segmentation and a Multilayer Topographic Feature Analysis  

Microsoft Academic Search

Rationale and Objectives. We developed and evaluated a computer- aided detection (CAD) scheme for masses in digitized mammograms. Methods. A multistep CAD scheme was developed and tested. The method uses a technique of single-image segmentation with Gaussian bandpass filtering to yield a high sensitivity for mass detection. A rule- based multilayer topographic feature analysis method is then used to clas-

Bin Zheng; Yuan-Hsiang Chang; David Gur

209

Beyond Corridor Reliability Measures: Analysis of Freeway Travel Time Reliability at the1 Segment Level for Hotspot Identification2  

E-print Network

Beyond Corridor Reliability Measures: Analysis of Freeway Travel Time Reliability at the1 Segment and Bertini 2 Abstract. Travel time based performance measures are widely used for transportation systems and particularly1 freeways. However, it has become evident that travel time reliability, taking into account

Bertini, Robert L.

210

Geographic information systems and spatial analysis of market segmentation for community banks.  

E-print Network

??The purpose of this research was to determine the value of incorporating consumer behavioral datasets, specifically lifestyle market segmentation, into traditional site selection and location… (more)

Parrish, Jason S.

2009-01-01

211

A comparison between handgrip strength, upper limb fat free mass by segmental bioelectrical impedance analysis (SBIA) and anthropometric measurements in young males  

NASA Astrophysics Data System (ADS)

The mechanical function and size of a muscle may be closely linked. Handgrip strength (HGS) has been used as a predictor of functional performing. Anthropometric measurements have been made to estimate arm muscle area (AMA) and physical muscle mass volume of upper limb (ULMMV). Electrical volume estimation is possible by segmental BIA measurements of fat free mass (SBIA-FFM), mainly muscle-mass. Relationship among these variables is not well established. We aimed to determine if physical and electrical muscle mass estimations relate to each other and to what extent HGS is to be related to its size measured by both methods in normal or overweight young males. Regression analysis was used to determine association between these variables. Subjects showed a decreased HGS (65.5%), FFM, (85.5%) and AMA (74.5%). It was found an acceptable association between SBIA-FFM and AMA (r2 = 0.60) and poorer between physical and electrical volume (r2 = 0.55). However, a paired Student t-test and Bland and Altman plot showed that physical and electrical models were not interchangeable (pt<0.0001). HGS showed a very weak association with anthropometric (r2 = 0.07) and electrical (r2 = 0.192) ULMMV showing that muscle mass quantity does not mean muscle strength. Other factors influencing HGS like physical training or nutrition require more research.

Gonzalez-Correa, C. H.; Caicedo-Eraso, J. C.; Varon-Serna, D. R.

2013-04-01

212

Semi-automatic segmentation and modeling of the cervical spinal cord for volume quantification in multiple sclerosis patients from magnetic resonance images  

NASA Astrophysics Data System (ADS)

Spinal cord (SC) tissue loss is known to occur in some patients with multiple sclerosis (MS), resulting in SC atrophy. Currently, no measurement tools exist to determine the magnitude of SC atrophy from Magnetic Resonance Images (MRI). We have developed and implemented a novel semi-automatic method for quantifying the cervical SC volume (CSCV) from Magnetic Resonance Images (MRI) based on level sets. The image dataset consisted of SC MRI exams obtained at 1.5 Tesla from 12 MS patients (10 relapsing-remitting and 2 secondary progressive) and 12 age- and gender-matched healthy volunteers (HVs). 3D high resolution image data were acquired using an IR-FSPGR sequence acquired in the sagittal plane. The mid-sagittal slice (MSS) was automatically located based on the entropy calculation for each of the consecutive sagittal slices. The image data were then pre-processed by 3D anisotropic diffusion filtering for noise reduction and edge enhancement before segmentation with a level set formulation which did not require re-initialization. The developed method was tested against manual segmentation (considered ground truth) and intra-observer and inter-observer variability were evaluated.

Sonkova, Pavlina; Evangelou, Iordanis E.; Gallo, Antonio; Cantor, Fredric K.; Ohayon, Joan; McFarland, Henry F.; Bagnato, Francesca

2008-03-01

213

Reducing pervasive false-positive identical-by-descent segments detected by large-scale pedigree analysis.  

PubMed

Analysis of genomic segments shared identical-by-descent (IBD) between individuals is fundamental to many genetic applications, from demographic inference to estimating the heritability of diseases, but IBD detection accuracy in nonsimulated data is largely unknown. In principle, it can be evaluated using known pedigrees, as IBD segments are by definition inherited without recombination down a family tree. We extracted 25,432 genotyped European individuals containing 2,952 father-mother-child trios from the 23andMe, Inc. data set. We then used GERMLINE, a widely used IBD detection method, to detect IBD segments within this cohort. Exploiting known familial relationships, we identified a false-positive rate over 67% for 2-4 centiMorgan (cM) segments, in sharp contrast with accuracies reported in simulated data at these sizes. Nearly all false positives arose from the allowance of haplotype switch errors when detecting IBD, a necessity for retrieving long (>6 cM) segments in the presence of imperfect phasing. We introduce HaploScore, a novel, computationally efficient metric that scores IBD segments proportional to the number of switch errors they contain. Applying HaploScore filtering to the IBD data at a precision of 0.8 produced a 13-fold increase in recall when compared with length-based filtering. We replicate the false IBD findings and demonstrate the generalizability of HaploScore to alternative data sources using an independent cohort of 555 European individuals from the 1000 Genomes project. HaploScore can improve the accuracy of segments reported by any IBD detection method, provided that estimates of the genotyping error rate and switch error rate are available. PMID:24784137

Durand, Eric Y; Eriksson, Nicholas; McLean, Cory Y

2014-08-01

214

Reducing Pervasive False-Positive Identical-by-Descent Segments Detected by Large-Scale Pedigree Analysis  

PubMed Central

Analysis of genomic segments shared identical-by-descent (IBD) between individuals is fundamental to many genetic applications, from demographic inference to estimating the heritability of diseases, but IBD detection accuracy in nonsimulated data is largely unknown. In principle, it can be evaluated using known pedigrees, as IBD segments are by definition inherited without recombination down a family tree. We extracted 25,432 genotyped European individuals containing 2,952 father–mother–child trios from the 23andMe, Inc. data set. We then used GERMLINE, a widely used IBD detection method, to detect IBD segments within this cohort. Exploiting known familial relationships, we identified a false-positive rate over 67% for 2–4 centiMorgan (cM) segments, in sharp contrast with accuracies reported in simulated data at these sizes. Nearly all false positives arose from the allowance of haplotype switch errors when detecting IBD, a necessity for retrieving long (>6 cM) segments in the presence of imperfect phasing. We introduce HaploScore, a novel, computationally efficient metric that scores IBD segments proportional to the number of switch errors they contain. Applying HaploScore filtering to the IBD data at a precision of 0.8 produced a 13-fold increase in recall when compared with length-based filtering. We replicate the false IBD findings and demonstrate the generalizability of HaploScore to alternative data sources using an independent cohort of 555 European individuals from the 1000 Genomes project. HaploScore can improve the accuracy of segments reported by any IBD detection method, provided that estimates of the genotyping error rate and switch error rate are available. PMID:24784137

Durand, Eric Y.; Eriksson, Nicholas; McLean, Cory Y.

2014-01-01

215

Multi-Scale and Object-Oriented Analysis for Mountain Terrain Segmentation and Geomorphological Assessment  

NASA Astrophysics Data System (ADS)

Digital terrain analysis of mountain topography is widely utilized for mapping landforms, assessing the role of surface processes in landscape evolution, and estimating the spatial variation of erosion. Numerous geomorphometry techniques exist to characterize terrain surface parameters, although their utility to characterize the spatial hierarchical structure of the topography and permit an assessment of the erosion/tectonic impact on the landscape is very limited due to scale and data integration issues. To address this problem, we apply scale-dependent geomorphometric and object-oriented analyses to characterize the hierarchical spatial structure of mountain topography. Specifically, we utilized a high resolution digital elevation model to characterize complex topography in the Shimshal Valley in the Western Himalaya of Pakistan. To accomplish this, we generate terrain objects (geomorphological features and landform) including valley floors and walls, drainage basins, drainage network, ridge network, slope facets, and elemental forms based upon curvature. Object-oriented analysis was used to characterize object properties accounting for object size, shape, and morphometry. The spatial overlay and integration of terrain objects at various scales defines the nature of the hierarchical organization. Our results indicate that variations in the spatial complexity of the terrain hierarchical organization is related to the spatio-temporal influence of surface processes and landscape evolution dynamics. Terrain segmentation and the integration of multi-scale terrain information permits further assessment of process domains and erosion, tectonic impact potential, and natural hazard potential. We demonstrate this with landform mapping and geomorphological assessment examples.

Marston, B. K.; Bishop, M. P.; Shroder, J. F.

2009-12-01

216

Stereophotogrammetrie Mass Distribution Parameter Determination Of The Lower Body Segments For Use In Gait Analysis  

NASA Astrophysics Data System (ADS)

Inclusion of mass distribution information in biomechanical analysis of motion is a requirement for the accurate calculation of external moments and forces acting on the segmental joints during locomotion. Regression equations produced from a variety of photogrammetric, anthropometric and cadaeveric studies have been developed and espoused in literature. Because of limitations in the accuracy of predicted inertial properties based on the application of regression equation developed on one population and then applied on a different study population, the employment of a measurement technique that accurately defines the shape of each individual subject measured is desirable. This individual data acquisition method is especially needed when analyzing the gait of subjects with large differences in their extremity geo-metry from those considered "normal", or who may possess gross asymmetries in shape in their own contralateral limbs. This study presents the photogrammetric acquisition and data analysis methodology used to assess the inertial tensors of two groups of subjects, one with spastic diplegic cerebral palsy and the other considered normal.

Sheffer, Daniel B.; Schaer, Alex R.; Baumann, Juerg U.

1989-04-01

217

Interactive 3D segmentation of the prostate in magnetic resonance images using shape and local appearance similarity analysis  

NASA Astrophysics Data System (ADS)

3D segmentation of the prostate in medical images is useful to prostate cancer diagnosis and therapy guidance, but is time-consuming to perform manually. Clinical translation of computer-assisted segmentation algorithms for this purpose requires a comprehensive and complementary set of evaluation metrics that are informative to the clinical end user. We have developed an interactive 3D prostate segmentation method for 1.5T and 3.0T T2-weighted magnetic resonance imaging (T2W MRI) acquired using an endorectal coil. We evaluated our method against manual segmentations of 36 3D images using complementary boundary-based (mean absolute distance; MAD), regional overlap (Dice similarity coefficient; DSC) and volume difference (?V) metrics. Our technique is based on inter-subject prostate shape and local boundary appearance similarity. In the training phase, we calculated a point distribution model (PDM) and a set of local mean intensity patches centered on the prostate border to capture shape and appearance variability. To segment an unseen image, we defined a set of rays - one corresponding to each of the mean intensity patches computed in training - emanating from the prostate centre. We used a radial-based search strategy and translated each mean intensity patch along its corresponding ray, selecting as a candidate the boundary point with the highest normalized cross correlation along each ray. These boundary points were then regularized using the PDM. For the whole gland, we measured a mean+/-std MAD of 2.5+/-0.7 mm, DSC of 80+/-4%, and ?V of 1.1+/-8.8 cc. We also provided an anatomic breakdown of these metrics within the prostatic base, mid-gland, and apex.

Shahedi, Maysam; Fenster, Aaron; Cool, Derek W.; Romagnoli, Cesare; Ward, Aaron D.

2013-03-01

218

Edge preserving smoothing and segmentation of 4-D images via transversely isotropic scale-space processing and fingerprint analysis  

SciTech Connect

Enhancements are described for an approach that unifies edge preserving smoothing with segmentation of time sequences of volumetric images, based on differential edge detection at multiple spatial and temporal scales. Potential applications of these 4-D methods include segmentation of respiratory gated positron emission tomography (PET) transmission images to improve accuracy of attenuation correction for imaging heart and lung lesions, and segmentation of dynamic cardiac single photon emission computed tomography (SPECT) images to facilitate unbiased estimation of time-activity curves and kinetic parameters for left ventricular volumes of interest. Improved segmentation of lung surfaces in simulated respiratory gated cardiac PET transmission images is achieved with a 4-D edge detection operator composed of edge preserving 1-D operators applied in various spatial and temporal directions. Smoothing along the axis of a 1-D operator is driven by structure separation seen in the scale-space fingerprint, rather than by image contrast. Spurious noise structures are reduced with use of small-scale isotropic smoothing in directions transverse to the 1-D operator axis. Analytic expressions are obtained for directional derivatives of the smoothed, edge preserved image, and the expressions are used to compose a 4-D operator that detects edges as zero-crossings in the second derivative in the direction of the image intensity gradient. Additional improvement in segmentation is anticipated with use of multiscale transversely isotropic smoothing and a novel interpolation method that improves the behavior of the directional derivatives. The interpolation method is demonstrated on a simulated 1-D edge and incorporation of the method into the 4-D algorithm is described.

Reutter, Bryan W.; Algazi, V. Ralph; Gullberg, Grant T; Huesman, Ronald H.

2004-01-19

219

Welsh Hotel: Cost-Volume-Profit Analysis and Uncertainty  

Microsoft Academic Search

Hotels tend to have a high level of fixed costs, which means that high losses will result if revenue is significantly reduced below the break-even point. Hence, the traditional cost-volume-profit (CVP) model, which is widely used within the hotel sector to determine break-even analysis, is an important managerial tool. However, is the basic CVP model adequate, bearing in mind that

Paul A. Phillips

1994-01-01

220

Dealing with Fuzziness in Cost-Volume-Profit Analysis  

Microsoft Academic Search

A major limitation of the traditional cost-volume-profit (CVP) analysis is its inability to account for uncertainty and risk. This deficiency has been resolved by the development of probabilistic and stochastic CVP models which require precise numerical assessment of uncertainties in sales demand. There remains, however, imprecision in the expert's assessment of the sales demand distribution. Sub-optimal decisions may result because

Y. Lilian Chan; Yufei Yuan

1990-01-01

221

Automated segmentation and fractal analysis of high-resolution non-invasive capillary perfusion maps of the human retina  

PubMed Central

The retina provides a window to study the pathophysiology of cerebrovascular diseases. Pathological retinal microvascular changes may reflect microangiopathic processes in the brain. Recent advances in optical imaging techniques have enabled imaging of the retinal microvasculature at the capillary level, and the generation of high-resolution, non-invasive capillary perfusion maps (nCPMs) with the Retinal Function Imager (RFI). However, the lack of quantitative analyses of the nCPMs may limit the wider application of the method in clinical research. The goal of this project was to demonstrate the feasibility of automated segmentation and fractal analysis of nCPMs. We took two nCPMs of each subject in a group of 6 healthy volunteers and used our segmentation algorithm to do the automated segmentation for monofractal and multifractal analyses. The monofractal dimension was 1.885 ± 0.020, and the multifractal dimension was 1.876 ± 0.010 (P =0.108). The coefficient of repeatability was 0.070 for monofractal analysis and 0.026 for multifractal analysis. This study demonstrated that the automatic segmentation of nCPMs is feasible for fractal analyses. Both monofractal and multifractal analyses yielded similar results. The quantitative analyses of microvasculature at the capillary level may open up a new era for studying the microvascular diseases such as cerebral small vessel disease. PMID:23806780

Jiang, Hong; DeBuc, Delia Cabrera; Rundek, Tatjana; Lam, Byron L; Wright, Clinton B.; Shen, Meixiao; Tao, Aizhu; Wang, Jianhua

2013-01-01

222

UNSUPERVISED MINING OF AUDIOVISUALLY CONSISTENT SEGMENTS IN VIDEOS WITH APPLICATION TO STRUCTURE ANALYSIS  

E-print Network

UNSUPERVISED MINING OF AUDIOVISUALLY CONSISTENT SEGMENTS IN VIDEOS WITH APPLICATION TO STRUCTURE technique is proposed to discover repeating video segments exhibiting audio and visual con- sistency accurate detection of the underlying event throughout the video. Event min- ing is applied to unsupervised

Paris-Sud XI, Université de

223

Manjari I. Rao Analysis of a Locally Varying Intensity Template for Segmentation of  

E-print Network

of Kidneys in CT Images (Under the supervision of Edward L. Chaney, PhD) The purpose of this study was to evaluate the use of a locally varying intensity template for automatic segmentation of kidneys in CT images. Kidney segmentation is often difficult because the surrounding soft tissue has varying contrast across

North Carolina at Chapel Hill, University of

224

Understanding the market for geographic information: A market segmentation and characteristics analysis  

NASA Technical Reports Server (NTRS)

Findings and results from a marketing research study are presented. The report identifies market segments and the product types to satisfy demand in each. An estimate of market size is based on the specific industries in each segment. A sample of ten industries was used in the study. The scientific study covered U.S. firms only.

Piper, William S.; Mick, Mark W.

1994-01-01

225

A Theoretical Analysis of How Segmentation of Dynamic Visualizations Optimizes Students' Learning  

ERIC Educational Resources Information Center

This article reviews studies investigating segmentation of dynamic visualizations (i.e., showing dynamic visualizations in pieces with pauses in between) and discusses two not mutually exclusive processes that might underlie the effectiveness of segmentation. First, cognitive activities needed for dealing with the transience of dynamic…

Spanjers, Ingrid A. E.; van Gog, Tamara; van Merrienboer, Jeroen J. G.

2010-01-01

226

A Unified Set of Analysis Tools for Uterine Cervix Image Segmentation  

PubMed Central

Segmentation is a fundamental component of many medical image processing applications, and it has long been recognized as a challenging problem. In this paper, we report our research and development efforts on analyzing and extracting clinically meaningful regions from uterine cervix images in a large database created for the study of cervical cancer. In addition to proposing new algorithms, we also focus on developing open source tools which are in synchrony with the research objectives. These efforts have resulted in three Web-accessible tools which address three important and interrelated sub-topics in medical image segmentation, respectively: the BMT (Boundary Marking Tool), CST (Cervigram Segmentation Tool), and MOSES (Multi-Observer Segmentation Evaluation System). The BMT is for manual segmentation, typically to collect “ground truth” image regions from medical experts. The CST is for automatic segmentation, and MOSES is for segmentation evaluation. These tools are designed to be a unified set in which data can be conveniently exchanged. They have value not only for improving the reliability and accuracy of algorithms of uterine cervix image segmentation, but also promoting collaboration between biomedical experts and engineers which are crucial to medical image processing applications. Although the CST is designed for the unique characteristics of cervigrams, the BMT and MOSES are very general and extensible, and can be easily adapted to other biomedical image collections. PMID:20510585

Xue, Zhiyun; Long, Rodney; Antani, Sameer; Neve, Leif; Zhu, Yaoyao; Thoma, George

2010-01-01

227

Microfluidic Chip for High Efficiency Electrophoretic Analysis of Segmented Flow from a Microdialysis Probe and in Vivo Chemical Monitoring  

PubMed Central

An effective method for in vivo chemical monitoring is to couple sampling probes, such as microdialysis, to on-line analytical methods. A limitation of this approach is that in vivo chemical dynamics may be distorted by flow and diffusion broadening during transfer from sampling probe to analytical system. Converting a homogenous sample stream to segmented flow can prevent such broadening. We have developed a system for coupling segmented microdialysis flow with chip-based electrophoresis. In this system, the dialysis probe is integrated with a PDMS chip that merges dialysate with fluorogenic reagent and segments the flow into 8–10 nL plugs at 0.3–0.5 Hz separated by perfluorodecalin. The plugs flow to a glass chip where they are extracted to an aqueous stream and analyzed by electrophoresis with fluorescence detection. The novel extraction system connects the segmented flow to an electrophoresis sampling channel by a shallow and hydrophilic extraction bridge that removes the entire aqueous droplet from the oil stream. With this approach, temporal resolution was 35 s and independent of distance between sampling and analysis. Electrophoretic analysis produced separation with 223,000 ± 21,000 theoretical plates, 4.4% RSD in peak height, and detection limits of 90–180 nM for six amino acids. This performance was made possible by three key elements: 1) reliable transfer of plug flow to a glass chip; 2) efficient extraction of aqueous plugs from segmented flow; and 3) electrophoretic injection suitable for high efficiency separation with minimal dilution of sample. The system was used to detect rapid concentration changes evoked by infusing glutamate uptake inhibitor into the striatum of anesthetized rats. These results demonstrate the potential of incorporating segmented flow into separations-based sensing schemes for studying chemical dynamics in vivo with improved temporal resolution. PMID:19803495

Wang, Meng; Roman, Gregory T.; Perry, Maura L.; Kennedy, Robert T.

2009-01-01

228

Structural and Functional Analysis of Transmembrane Segment IV of the Salt Tolerance Protein Sod2*  

PubMed Central

Sod2 is the plasma membrane Na+/H+ exchanger of the fission yeast Schizosaccharomyces pombe. It provides salt tolerance by removing excess intracellular sodium (or lithium) in exchange for protons. We examined the role of amino acid residues of transmembrane segment IV (TM IV) (126FPQINFLGSLLIAGCITSTDPVLSALI152) in activity by using alanine scanning mutagenesis and examining salt tolerance in sod2-deficient S. pombe. Two amino acids were critical for function. Mutations T144A and V147A resulted in defective proteins that did not confer salt tolerance when reintroduced into S. pombe. Sod2 protein with other alanine mutations in TM IV had little or no effect. T144D and T144K mutant proteins were inactive; however, a T144S protein was functional and provided lithium, but not sodium, tolerance and transport. Analysis of sensitivity to trypsin indicated that the mutations caused a conformational change in the Sod2 protein. We expressed and purified TM IV (amino acids 125–154). NMR analysis yielded a model with two helical regions (amino acids 128–142 and 147–154) separated by an unwound region (amino acids 143–146). Molecular modeling of the entire Sod2 protein suggested that TM IV has a structure similar to that deduced by NMR analysis and an overall structure similar to that of Escherichia coli NhaA. TM IV of Sod2 has similarities to TM V of the Zygosaccharomyces rouxii Na+/H+ exchanger and TM VI of isoform 1 of mammalian Na+/H+ exchanger. TM IV of Sod2 is critical to transport and may be involved in cation binding or conformational changes of the protein. PMID:23836910

Ullah, Asad; Kemp, Grant; Lee, Brian; Alves, Claudia; Young, Howard; Sykes, Brian D.; Fliegel, Larry

2013-01-01

229

Magnetic Field Analysis of Lorentz Motors Using a Novel Segmented Magnetic Equivalent Circuit Method  

PubMed Central

A simple and accurate method based on the magnetic equivalent circuit (MEC) model is proposed in this paper to predict magnetic flux density (MFD) distribution of the air-gap in a Lorentz motor (LM). In conventional MEC methods, the permanent magnet (PM) is treated as one common source and all branches of MEC are coupled together to become a MEC network. In our proposed method, every PM flux source is divided into three sub-sections (the outer, the middle and the inner). Thus, the MEC of LM is divided correspondingly into three independent sub-loops. As the size of the middle sub-MEC is small enough, it can be treated as an ideal MEC and solved accurately. Combining with decoupled analysis of outer and inner MECs, MFD distribution in the air-gap can be approximated by a quadratic curve, and the complex calculation of reluctances in MECs can be avoided. The segmented magnetic equivalent circuit (SMEC) method is used to analyze a LM, and its effectiveness is demonstrated by comparison with FEA, conventional MEC and experimental results. PMID:23358368

Qian, Junbing; Chen, Xuedong; Chen, Han; Zeng, Lizhan; Li, Xiaoqing

2013-01-01

230

Clonal analysis of segmental and compartmental homoeotic transformations in polycomb mutants of Drosophila melanogaster.  

PubMed

We describe two new effects of Polycomb mutations on the determination of compartments in the wing of Drosophila. Ventral and posterior wing compartments are transformed partially to their dorsal and anterior counterparts. Although these new phenotypes are most strongly expressed in lethal pharate adults heteroallelic for Pc2 and a new allele PcT2, they are also found regularly but with low expressivity as dominant phenotypes of all the other Pc alleles we tested. Several different intersegmental homoeotic transformations caused by Polycomb have previously been described, leading to the hypothesis that Polycomb regulates the activity of certain selector genes normally active in specific segments. We now show that the degree of expression of the inter- and intrasegmental transformations are highly correlated in a range of different Pc genotypes, and that more than one determinative decision can be affected in a single compartment. This suggests that the wild-type Pc product may act as a general regulator of several different selector genes so as to influence both early embryonic and later determinative decisions in the imaginal discs. To test this idea we used clonal analysis to look at the effects of Pc on clonal restrictions at the dorsoventral and anterioposterior compartment boundaries, and its time of action with respect to each phenotype. PMID:1976555

Tiong, S Y; Russell, M A

1990-10-01

231

Volume analysis of heat-induced cracks in human molars: A preliminary study  

PubMed Central

Context: Only a few methods have been published dealing with the visualization of heat-induced cracks inside bones and teeth. Aims: As a novel approach this study used nondestructive X-ray microtomography (micro-CT) for volume analysis of heat-induced cracks to observe the reaction of human molars to various levels of thermal stress. Materials and Methods: Eighteen clinically extracted third molars were rehydrated and burned under controlled temperatures (400, 650, and 800°C) using an electric furnace adjusted with a 25°C increase/min. The subsequent high-resolution scans (voxel-size 17.7 ?m) were made with a compact micro-CT scanner (SkyScan 1174). In total, 14 scans were automatically segmented with Definiens XD Developer 1.2 and three-dimensional (3D) models were computed with Visage Imaging Amira 5.2.2. The results of the automated segmentation were analyzed with an analysis of variance (ANOVA) and uncorrected post hoc least significant difference (LSD) tests using Statistical Package for Social Sciences (SPSS) 17. A probability level of P < 0.05 was used as an index of statistical significance. Results: A temperature-dependent increase of heat-induced cracks was observed between the three temperature groups (P < 0.05, ANOVA post hoc LSD). In addition, the distributions and shape of the heat-induced changes could be classified using the computed 3D models. Conclusion: The macroscopic heat-induced changes observed in this preliminary study correspond with previous observations of unrestored human teeth, yet the current observations also take into account the entire microscopic 3D expansions of heat-induced cracks within the dental hard tissues. Using the same experimental conditions proposed in the literature, this study confirms previous results, adds new observations, and offers new perspectives in the investigation of forensic evidence. PMID:25125923

Sandholzer, Michael A.; Baron, Katharina; Heimel, Patrick; Metscher, Brian D.

2014-01-01

232

Fast segmentation and high-quality three-dimensional volume mesh creation from medical images for diffuse optical tomography  

NASA Astrophysics Data System (ADS)

Multimodal approaches that combine near-infrared (NIR) and conventional imaging modalities have been shown to improve optical parameter estimation dramatically and thus represent a prevailing trend in NIR imaging. These approaches typically involve applying anatomical templates from magnetic resonance imaging/computed tomography/ultrasound images to guide the recovery of optical parameters. However, merging these data sets using current technology requires multiple software packages, substantial expertise, significant time-commitment, and often results in unacceptably poor mesh quality for optical image reconstruction, a reality that represents a significant roadblock for translational research of multimodal NIR imaging. This work addresses these challenges directly by introducing automated digital imaging and communications in medicine image stack segmentation and a new one-click three-dimensional mesh generator optimized for multimodal NIR imaging, and combining these capabilities into a single software package (available for free download) with a streamlined workflow. Image processing time and mesh quality benchmarks were examined for four common multimodal NIR use-cases (breast, brain, pancreas, and small animal) and were compared to a commercial image processing package. Applying these tools resulted in a fivefold decrease in image processing time and 62% improvement in minimum mesh quality, in the absence of extra mesh postprocessing. These capabilities represent a significant step toward enabling translational multimodal NIR research for both expert and nonexpert users in an open-source platform.

Jermyn, Michael; Ghadyani, Hamid; Mastanduno, Michael A.; Turner, Wes; Davis, Scott C.; Dehghani, Hamid; Pogue, Brian W.

2013-08-01

233

Segmental Quantitative MR Imaging Analysis of Diurnal Variation of Water Content in the Lumbar Intervertebral Discs  

PubMed Central

Objective To investigate the changes in water content in the lumbar intervertebral discs by quantitative T2 MR imaging in the morning after bed rest and evening after a diurnal load. Materials and Methods Twenty healthy volunteers were separately examined in the morning after bed rest and in the evening after finishing daily work. T2-mapping images were obtained and analyzed. An equally-sized rectangular region of interest (ROI) was manually placed in both, the anterior and the posterior annulus fibrosus (AF), in the outermost 20% of the disc. Three ROIs were placed in the space defined as the nucleus pulposus (NP). Repeated-measures analysis of variance and paired 2-tailed t tests were used for statistical analysis, with p < 0.05 as significantly different. Results T2 values significantly decreased from morning to evening, in the NP (anterior NP = -13.9 ms; central NP = -17.0 ms; posterior NP = -13.3 ms; all p < 0.001). Meanwhile T2 values significantly increased in the anterior AF (+2.9 ms; p = 0.025) and the posterior AF (+5.9 ms; p < 0.001). T2 values in the posterior AF showed the largest degree of variation among the 5 ROIs, but there was no statistical significance (p = 0.414). Discs with initially low T2 values in the center NP showed a smaller degree of variation in the anterior NP and in the central NP, than in discs with initially high T2 values in the center NP (10.0% vs. 16.1%, p = 0.037; 6.4% vs. 16.1%, p = 0.006, respectively). Conclusion Segmental quantitative T2 MRI provides valuable insights into physiological aspects of normal discs.

Zhu, Tingting; Ai, Tao; Zhang, Wei; Li, Tao

2015-01-01

234

Automatic Segmentation of Blood Vessels in Colour Retinal Images using Spatial Gabor Filter and Multiscale Analysis  

Microsoft Academic Search

Retinal blood vessels are significant anatomical structures in ophthalmic images. Automatic segmentation of blood vessels\\u000a is one of the important steps in computer aided diagnosis system for the detection of diseases such as Diabetic Retinopathy\\u000a that affect human retina. We propose a method for the segmentation of retinal blood vessels using Spatial Gabor filters as\\u000a they can be tuned to

P. C. Siddalingaswamy; K. Gopalakrishna Prabhu

235

An approach to a comprehensive test framework for analysis and evaluation of text line segmentation algorithms.  

PubMed

The paper introduces a testing framework for the evaluation and validation of text line segmentation algorithms. Text line segmentation represents the key action for correct optical character recognition. Many of the tests for the evaluation of text line segmentation algorithms deal with text databases as reference templates. Because of the mismatch, the reliable testing framework is required. Hence, a new approach to a comprehensive experimental framework for the evaluation of text line segmentation algorithms is proposed. It consists of synthetic multi-like text samples and real handwritten text as well. Although the tests are mutually independent, the results are cross-linked. The proposed method can be used for different types of scripts and languages. Furthermore, two different procedures for the evaluation of algorithm efficiency based on the obtained error type classification are proposed. The first is based on the segmentation line error description, while the second one incorporates well-known signal detection theory. Each of them has different capabilities and convenience, but they can be used as supplements to make the evaluation process efficient. Overall the proposed procedure based on the segmentation line error description has some advantages, characterized by five measures that describe measurement procedures. PMID:22164106

Brodic, Darko; Milivojevic, Dragan R; Milivojevic, Zoran N

2011-01-01

236

Cell segmentation by multi-resolution analysis and maximum likelihood estimation (MAMLE)  

PubMed Central

Background Cell imaging is becoming an indispensable tool for cell and molecular biology research. However, most processes studied are stochastic in nature, and require the observation of many cells and events. Ideally, extraction of information from these images ought to rely on automatic methods. Here, we propose a novel segmentation method, MAMLE, for detecting cells within dense clusters. Methods MAMLE executes cell segmentation in two stages. The first relies on state of the art filtering technique, edge detection in multi-resolution with morphological operator and threshold decomposition for adaptive thresholding. From this result, a correction procedure is applied that exploits maximum likelihood estimate as an objective function. Also, it acquires morphological features from the initial segmentation for constructing the likelihood parameter, after which the final segmentation is obtained. Conclusions We performed an empirical evaluation that includes sample images from different imaging modalities and diverse cell types. The new method attained very high (above 90%) cell segmentation accuracy in all cases. Finally, its accuracy was compared to several existing methods, and in all tests, MAMLE outperformed them in segmentation accuracy. PMID:24267594

2013-01-01

237

An Approach to a Comprehensive Test Framework for Analysis and Evaluation of Text Line Segmentation Algorithms  

PubMed Central

The paper introduces a testing framework for the evaluation and validation of text line segmentation algorithms. Text line segmentation represents the key action for correct optical character recognition. Many of the tests for the evaluation of text line segmentation algorithms deal with text databases as reference templates. Because of the mismatch, the reliable testing framework is required. Hence, a new approach to a comprehensive experimental framework for the evaluation of text line segmentation algorithms is proposed. It consists of synthetic multi-like text samples and real handwritten text as well. Although the tests are mutually independent, the results are cross-linked. The proposed method can be used for different types of scripts and languages. Furthermore, two different procedures for the evaluation of algorithm efficiency based on the obtained error type classification are proposed. The first is based on the segmentation line error description, while the second one incorporates well-known signal detection theory. Each of them has different capabilities and convenience, but they can be used as supplements to make the evaluation process efficient. Overall the proposed procedure based on the segmentation line error description has some advantages, characterized by five measures that describe measurement procedures. PMID:22164106

Brodic, Darko; Milivojevic, Dragan R.; Milivojevic, Zoran N.

2011-01-01

238

Airway segmentation and analysis for the study of mouse models of lung disease using micro-CT  

NASA Astrophysics Data System (ADS)

Animal models of lung disease are gaining importance in understanding the underlying mechanisms of diseases such as emphysema and lung cancer. Micro-CT allows in vivo imaging of these models, thus permitting the study of the progression of the disease or the effect of therapeutic drugs in longitudinal studies. Automated analysis of micro-CT images can be helpful to understand the physiology of diseased lungs, especially when combined with measurements of respiratory system input impedance. In this work, we present a fast and robust murine airway segmentation and reconstruction algorithm. The algorithm is based on a propagating fast marching wavefront that, as it grows, divides the tree into segments. We devised a number of specific rules to guarantee that the front propagates only inside the airways and to avoid leaking into the parenchyma. The algorithm was tested on normal mice, a mouse model of chronic inflammation and a mouse model of emphysema. A comparison with manual segmentations of two independent observers shows that the specificity and sensitivity values of our method are comparable to the inter-observer variability, and radius measurements of the mainstem bronchi reveal significant differences between healthy and diseased mice. Combining measurements of the automatically segmented airways with the parameters of the constant phase model provides extra information on how disease affects lung function.

Artaechevarria, X.; Pérez-Martín, D.; Ceresa, M.; de Biurrun, G.; Blanco, D.; Montuenga, L. M.; van Ginneken, B.; Ortiz-de-Solorzano, C.; Muñoz-Barrutia, A.

2009-11-01

239

Mitochondrial DNA diversity in Atherina boyeri populations as determined by RFLP analysis of three mtDNA segments  

Microsoft Academic Search

The genetic differentiation and the phylogenetic relationships of eight Atherina boyeri Greek populations have been investigated at the mtDNA level. The populations studied are from two different lakes, a lagoon, the interface zone between the lagoon and the sea, and four marine sites. RFLP analysis of three mtDNA segments (12s rRNA, 16s rRNA and D-loop) amplified by PCR was used.

E Klossa-Kilia; M Prassa; V Papasotiropoulos; S Alahiotis; G Kilias

2002-01-01

240

Simplifying the spectral analysis of the volume operator  

E-print Network

The volume operator plays a central role in both the kinematics and dynamics of canonical approaches to quantum gravity which are based on algebras of generalized Wilson loops. We introduce a method for simplifying its spectral analysis, for quantum states that can be realized on a cubic three-dimensional lattice. This involves a decomposition of Hilbert space into sectors transforming according to the irreducible representations of a subgroup of the cubic group. As an application, we determine the complete spectrum for a class of states with six-valent intersections.

R. Loll

1997-06-13

241

Parallel runway requirement analysis study. Volume 1: The analysis  

NASA Technical Reports Server (NTRS)

The correlation of increased flight delays with the level of aviation activity is well recognized. A main contributor to these flight delays has been the capacity of airports. Though new airport and runway construction would significantly increase airport capacity, few programs of this type are currently underway, let alone planned, because of the high cost associated with such endeavors. Therefore, it is necessary to achieve the most efficient and cost effective use of existing fixed airport resources through better planning and control of traffic flows. In fact, during the past few years the FAA has initiated such an airport capacity program designed to provide additional capacity at existing airports. Some of the improvements that that program has generated thus far have been based on new Air Traffic Control procedures, terminal automation, additional Instrument Landing Systems, improved controller display aids, and improved utilization of multiple runways/Instrument Meteorological Conditions (IMC) approach procedures. A useful element to understanding potential operational capacity enhancements at high demand airports has been the development and use of an analysis tool called The PLAND_BLUNDER (PLB) Simulation Model. The objective for building this simulation was to develop a parametric model that could be used for analysis in determining the minimum safety level of parallel runway operations for various parameters representing the airplane, navigation, surveillance, and ATC system performance. This simulation is useful as: a quick and economical evaluation of existing environments that are experiencing IMC delays, an efficient way to study and validate proposed procedure modifications, an aid in evaluating requirements for new airports or new runways in old airports, a simple, parametric investigation of a wide range of issues and approaches, an ability to tradeoff air and ground technology and procedures contributions, and a way of considering probable blunder mechanisms and range of blunder scenarios. This study describes the steps of building the simulation and considers the input parameters, assumptions and limitations, and available outputs. Validation results and sensitivity analysis are addressed as well as outlining some IMC and Visual Meteorological Conditions (VMC) approaches to parallel runways. Also, present and future applicable technologies (e.g., Digital Autoland Systems, Traffic Collision and Avoidance System II, Enhanced Situational Awareness System, Global Positioning Systems for Landing, etc.) are assessed and recommendations made.

Ebrahimi, Yaghoob S.

1993-01-01

242

Sequence analysis on the information of folding initiation segments in ferredoxin-like fold proteins  

PubMed Central

Background While some studies have shown that the 3D protein structures are more conservative than their amino acid sequences, other experimental studies have shown that even if two proteins share the same topology, they may have different folding pathways. There are many studies investigating this issue with molecular dynamics or Go-like model simulations, however, one should be able to obtain the same information by analyzing the proteins’ amino acid sequences, if the sequences contain all the information about the 3D structures. In this study, we use information about protein sequences to predict the location of their folding segments. We focus on proteins with a ferredoxin-like fold, which has a characteristic topology. Some of these proteins have different folding segments. Results Despite the simplicity of our methods, we are able to correctly determine the experimentally identified folding segments by predicting the location of the compact regions considered to play an important role in structural formation. We also apply our sequence analyses to some homologues of each protein and confirm that there are highly conserved folding segments despite the homologues’ sequence diversity. These homologues have similar folding segments even though the homology of two proteins’ sequences is not so high. Conclusion Our analyses have proven useful for investigating the common or different folding features of the proteins studied. PMID:24884463

2014-01-01

243

Chromosome segmental dosage analysis of maize morphogenesis using B-A-A translocations.  

PubMed

The B-A-A translocations have enabled us to simultaneously assess the possible dosage-sensitive interactions of two nonhomologous chromosome segments in affecting maize plant development. Maize B-A-A translocations contain segments of two nonhomologous essential A chromosomes in tandem arrangement attached to a segment of the long arm of a supernumerary B chromosome. By utilizing the frequent nondisjunction of the B centromere at the second pollen mitosis we produced plants containing an extra copy of the two A chromosome segments. We compared these hyperploid plants with nonhyperploid plants by measuring leaf width, plant height, ear height, internode length, stalk circumference, leaf length, and tassel-branch number in 20 paired families that involved one of the chromosome arms 1S, 1L, 4L, 5S, and 10L. One or more of the seven measured traits displayed dosage sensitivity among 17 of the 20 B-A-A translocations, which included the involvement of chromosome arms 2L, 3L, 5L, 6L, and 7L. The most obvious effect of an increased dosage of the B-A-A translocation was a significant decrease in the traits in the hyperploid plants. These effects may be either the additive effects of hyperploidy for the two chromosome segments or a result of gene interaction between them. PMID:18780743

Sheridan, William F; Auger, Donald L

2008-10-01

244

Tumor Burden Analysis on Computed Tomography by Automated Liver and Tumor Segmentation  

PubMed Central

The paper presents the automated computation of hepatic tumor burden from abdominal CT images of diseased populations with images with inconsistent enhancement. The automated segmentation of livers is addressed first. A novel three-dimensional (3D) affine invariant shape parameterization is employed to compare local shape across organs. By generating a regular sampling of the organ's surface, this parameterization can be effectively used to compare features of a set of closed 3D surfaces point-to-point, while avoiding common problems with the parameterization of concave surfaces. From an initial segmentation of the livers, the areas of atypical local shape are determined using training sets. A geodesic active contour corrects locally the segmentations of the livers in abnormal images. Graph cuts segment the hepatic tumors using shape and enhancement constraints. Liver segmentation errors are reduced significantly and all tumors are detected. Finally, support vector machines and feature selection are employed to reduce the number of false tumor detections. The tumor detection true position fraction of 100% is achieved at 2.3 false positives/case and the tumor burden is estimated with 0.9% error. Results from the test data demonstrate the method's robustness to analyze livers from difficult clinical cases to allow the temporal monitoring of patients with hepatic cancer. PMID:22893379

Linguraru, Marius George; Richbourg, William J.; Liu, Jianfei; Watt, Jeremy M.; Pamulapati, Vivek; Wang, Shijun; Summers, Ronald M.

2013-01-01

245

An analysis of methods for the selection of atlases for use in medical image segmentation  

NASA Astrophysics Data System (ADS)

The use of atlases has been shown to be a robust method for segmentation of medical images. In this paper we explore different methods of selection of atlases for the segmentation of the quadriceps muscles in magnetic resonance (MR) images, although the results are pertinent for a wide range of applications. The experiments were performed using 103 images from the Osteoarthritis Initiative (OAI). The images were randomly split into a training set consisting of 50 images and a testing set of 53 images. Three different atlas selection methods were systematically compared. First, a set of readers was assigned the task of selecting atlases from a training population of images, which were selected to be representative subgroups of the total population. Second, the same readers were instructed to select atlases from a subset of the training data which was stratified based on population modes. Finally, every image in the training set was employed as an atlas, with no input from the readers, and the atlas which had the best initial registration, judged by an appropriate registration metric, was used in the final segmentation procedure. The segmentation results were quantified using the Zijdenbos similarity index (ZSI). The results show that over all readers the agreement of the segmentation algorithm decreased from 0.76 to 0.74 when using population modes to assist in atlas selection. The use of every image in the training set as an atlas outperformed both manual atlas selection methods, achieving a ZSI of 0.82.

Prescott, Jeffrey W.; Best, Thomas M.; Haq, Furqan; Jackson, Rebecca; Gurcan, Metin

2010-03-01

246

Biomechanical comparison of mono-segment transpedicular fixation with short-segment fixation for treatment of thoracolumbar fractures: A finite element analysis.  

PubMed

Mono-segment transpedicular fixation is a method for the treatment of certain types of thoracolumbar spinal fracture. Finite element models were constructed to evaluate the biomechanics of mono-segment transpedicular fixation of thoracolumbar fracture. Spinal motion (T10-L2) was scanned and used to establish the models. The superior half of the cortical bone of T12 was removed and the superior half of the cancellous bone of the T12 body was assigned the material properties of injured bone to mimic vertebral fracture. Transpedicular fixation of T11 and T12 was performed to produce a mono-segment fixation model; T11 and L1 were fixed to produce a short-segment fixation model. Motion differences between functional units and von Mises stress on the spine and implants were measured under axial compression, anterior bending, extensional bending, lateral bending and axial rotation. We found no significant difference between mono- and short-segment fixations in the motion of any functional unit. Stress on the T10/T11 nucleus pulposus and T10/T11 and L1/L2 annulus fibrosus increased significantly by about 75% on anterior bending, extensional bending and lateral bending. In the fracture model, stress was increased by 24% at the inferior endplate of T10 and by 43% at the superior endplate of L2. All increased stresses were reduced after fixation and lower stress was observed with mono-segment fixation. In summary, the biomechanics of mono-segment pedicle screw instrumentation was similar to that of conventional short-segment fixation. As a minimally invasive treatment, mono-segment fixation would be appropriate for the treatment of selected thoracolumbar spinal fractures. PMID:25267283

Xu, Guijun; Fu, Xin; Du, Changling; Ma, Jianxiong; Li, Zhijun; Tian, Peng; Zhang, Tao; Ma, Xinlong

2014-10-01

247

Biomechanical analysis of C4-C6 spine segment considering anisotropy of annulus fibrosus.  

PubMed

Based on computed tomography scanning images of human cervical spine, this paper develops a detailed and anatomically accurate finite element model for C4-C6 motion segment to investigate its biomechanical responses. The model includes vertebrae, intervertebral disc, and various ligaments. The annulus fibrosus is characterized by using a previously developed nonlinear, anisotropic, hyperelastic fiber-reinforced model with fiber-matrix shear interaction considered. Other materials are simplified as linear or nonlinear elastic. The proposed cervical model is first validated by comparing numerical force-displacement relationship and intradiscal pressure under axial compression with experimental data available in the literature. The biomechanical responses of the spine segment under axial compression and rotation are then investigated. It is found that the fiber matrix-shear interaction of the annulus fibrosis plays an important role on appropriately predicting the biomechanical behavior of the cervical spine segment. PMID:23924518

Wang, Yu; Peng, Xiongqi; Guo, Zaoyang

2013-08-01

248

Multimodal Retinal Vessel Segmentation from Spectral-Domain Optical Coherence Tomography and Fundus Photography  

PubMed Central

Segmenting retinal vessels in optic nerve head (ONH) centered spectral-domain optical coherence tomography (SD-OCT) volumes is particularly challenging due to the projected neural canal opening (NCO) and relatively low visibility in the ONH center. Color fundus photographs provide a relatively high vessel contrast in the region inside the NCO, but have not been previously used to aid the SD-OCT vessel segmentation process. Thus, in this paper, we present two approaches for the segmentation of retinal vessels in SD-OCT volumes that each take advantage of complimentary information from fundus photographs. In the first approach (referred to as the registered-fundus vessel segmentation approach), vessels are first segmented on the fundus photograph directly (using a k-NN pixel classifier) and this vessel segmentation result is mapped to the SD-OCT volume through the registration of the fundus photograph to the SD-OCT volume. In the second approach (referred to as the multimodal vessel segmentation approach), after fundus-to-SD-OCT registration, vessels are simultaneously segmented with a k-NN classifier using features from both modalities. Three-dimensional structural information from the intraretinal layers and neural canal opening obtained through graph-theoretic segmentation approaches of the SD-OCT volume are used in combination with Gaussian filter banks and Gabor wavelets to generate the features. The approach is trained on 15 and tested on 19 randomly chosen independent image pairs of SD-OCT volumes and fundus images from 34 subjects with glaucoma. Based on a receiver operating characteristic (ROC) curve analysis, the present registered-fundus and multimodal vessel segmentation approaches [area under the curve (AUC) of 0.85 and 0.89, respectively] both perform significantly better than the two previous OCT-based approaches (AUC of 0.78 and 0.83, p < 0.05). The multimodal approach overall performs significantly better than the other three approaches (p < 0.05). PMID:22759443

Hu, Zhihong; Niemeijer, Meindert; Abràmoff, Michael D.; Garvin, Mona K.

2014-01-01

249

Volume  

NSDL National Science Digital Library

This interactive applet demonstrates volume as the number of unit cubes needed to fill a rectangular solid. The learner sees an animation and answers questions about the capacity of a box. The student can then ask for other problems where just the 3D dimensions are given and the volume is requested.

2011-01-01

250

Immunofluorescence laser micro-dissection of specific nephron segments in the mouse kidney allows targeted downstream proteomic analysis.  

PubMed

Laser micro-dissection (LMD) is a very useful tool that allows the isolation of finite areas from tissue specimens for downstream analysis of RNA and protein. Although LMD has been adapted for use in kidney tissue, the use of this powerful tool has been limited by the diminished ability to identify specific tubular segments in the kidney. In this study, we describe a major improvement in the methodology to isolate specific cells in the mouse kidney using immunofluorescence LMD (IF-LMD). Using IF-LMD, we can reproducibly isolate not only glomeruli, but also S1-S2 proximal segments, S3 tubules, and thick ascending limbs. We also demonstrate the utility of a novel rapid immunofluorescence staining technique, and provide downstream applications for IF-LMD such as real-time PCR and cutting-edge proteomic studies. This technical breakthrough may become an invaluable tool for understanding cellular and molecular events in the heterogeneous kidney milieu. PMID:25677553

Micanovic, Radmila; Khan, Shehnaz; El-Achkar, Tarek M

2015-02-01

251

Brain MRI Segmentation with Multiphase Minimal Partitioning: A Comparative Study  

PubMed Central

This paper presents the implementation and quantitative evaluation of a multiphase three-dimensional deformable model in a level set framework for automated segmentation of brain MRIs. The segmentation algorithm performs an optimal partitioning of three-dimensional data based on homogeneity measures that naturally evolves to the extraction of different tissue types in the brain. Random seed initialization was used to minimize the sensitivity of the method to initial conditions while avoiding the need for a priori information. This random initialization ensures robustness of the method with respect to the initialization and the minimization set up. Postprocessing corrections with morphological operators were applied to refine the details of the global segmentation method. A clinical study was performed on a database of 10 adult brain MRI volumes to compare the level set segmentation to three other methods: “idealized” intensity thresholding, fuzzy connectedness, and an expectation maximization classification using hidden Markov random fields. Quantitative evaluation of segmentation accuracy was performed with comparison to manual segmentation computing true positive and false positive volume fractions. A statistical comparison of the segmentation methods was performed through a Wilcoxon analysis of these error rates and results showed very high quality and stability of the multiphase three-dimensional level set method. PMID:18253474

Angelini, Elsa D.; Song, Ting; Mensh, Brett D.; Laine, Andrew F.

2007-01-01

252

Subcortical volume analysis in traumatic brain injury: the importance of the fronto-striato-thalamic circuit in task switching.  

PubMed

Traumatic brain injury (TBI) is associated with neuronal loss, diffuse axonal injury and executive dysfunction. Whereas executive dysfunction has traditionally been associated with prefrontal lesions, ample evidence suggests that those functions requiring behavioral flexibility critically depend on the interaction between frontal cortex, basal ganglia and thalamus. To test whether structural integrity of this fronto-striato-thalamic circuit can account for executive impairments in TBI we automatically segmented the thalamus, putamen and caudate of 25 patients and 21 healthy controls and obtained diffusion weighted images. We assessed components of executive function using the local-global task, which requires inhibition, updating and switching between actions. Shape analysis revealed localized atrophy of the limbic, executive and rostral-motor zones of the basal ganglia, whereas atrophy of the thalami was more global in TBI. This subcortical atrophy was related to white matter microstructural organization in TBI, suggesting that axonal injuries possibly contribute to subcortical volume loss. Global volume of the nuclei showed no clear relationship with task performance. However, the shape analysis revealed that participants with smaller volume of those subregions that have connections with the prefrontal cortex and rostral motor areas showed higher switch costs and mixing costs, and made more errors while switching. These results support the idea that flexible cognitive control over action depends on interactions within the fronto-striato-thalamic circuit. PMID:24290948

Leunissen, Inge; Coxon, James P; Caeyenberghs, Karen; Michiels, Karla; Sunaert, Stefan; Swinnen, Stephan P

2014-02-01

253

Complexity of genome evolution by segmental rearrangement in Brassica rapa revealed by sequence-level analysis  

Microsoft Academic Search

BACKGROUND: The Brassica species, related to Arabidopsis thaliana, include an important group of crops and represent an excellent system for studying the evolutionary consequences of polyploidy. Previous studies have led to a proposed structure for an ancestral karyotype and models for the evolution of the B. rapa genome by triplication and segmental rearrangement, but these have not been validated at

Martin Trick; Soo-Jin Kwon; Su Ryun Choi; Fiona Fraser; Eleni Soumpourou; Nizar Drou; Zhi Wang; Seo Yeon Lee; Tae-Jin Yang; Jeong-Hwan Mun; Andrew H Paterson; Christopher D Town; J Chris Pires; Yong Pyo Lim; Beom-Seok Park; Ian Bancroft

2009-01-01

254

Segmentation based on customer profitability — retrospective analysis of retail bank customer bases  

Microsoft Academic Search

Segmentation continues to be an important marketing concept also in a relationship marketing context. Relationship marketing is, however, more interested in enhancing the existing customer relationships and this generates a need for a better understanding of the existing customer base. The paper argues that “retrospective” or historical analyses, that facilitate the calculation of customer relationship profitability, form an excellent starting

Kaj Storbacka

1997-01-01

255

Segmental and Positional Effects on Children's Coda Production: Comparing Evidence from Perceptual Judgments and Acoustic Analysis  

ERIC Educational Resources Information Center

Children's early productions are highly variable. Findings from children's early productions of grammatical morphemes indicate that some of the variability is systematically related to segmental and phonological factors. Here, we extend these findings by assessing 2-year-olds' production of non-morphemic codas using both listener decisions and…

Theodore, Rachel M.; Demuth, Katherine; Shattuck-Hufnagel, Stephanie

2012-01-01

256

CT-scan images preprocessing and segmentation to improve bioprosthesis leaflets morphological analysis  

E-print Network

with other imaging techniques, we hypothesized that the processing of multi-detector CT images would allow, filtering, segmentation). Studied degenerated aortic bioprostheses were represented by two Carpentier techniques and valve durability are likely to have fueled this increase. On the other hand, the mortality

Paris-Sud XI, Université de

257

Flow Analysis on a Limited Volume Chilled Water System  

SciTech Connect

LANL Currently has a limited volume chilled water system for use in a glove box, but the system needs to be updated. Before we start building our new system, a flow analysis is needed to ensure that there are no high flow rates, extreme pressures, or any other hazards involved in the system. In this project the piping system is extremely important to us because it directly affects the overall design of the entire system. The primary components necessary for the chilled water piping system are shown in the design. They include the pipes themselves (perhaps of more than one diameter), the various fitting used to connect the individual pipes to form the desired system, the flow rate control devices (valves), and the pumps that add energy to the fluid. Even the most simple pipe systems are actually quite complex when they are viewed in terms of rigorous analytical considerations. I used an 'exact' analysis and dimensional analysis considerations combined with experimental results for this project. When 'real-world' effects are important (such as viscous effects in pipe flows), it is often difficult or impossible to use only theoretical methods to obtain the desired results. A judicious combination of experimental data with theoretical considerations and dimensional analysis are needed in order to reduce risks to an acceptable level.

Zheng, Lin [Los Alamos National Laboratory

2012-07-31

258

Segmental Analysis of Right Ventricular Longitudinal Deformation in Children before and after Percutaneous Closure of Atrial Septal Defect  

PubMed Central

Background The aim of study is to identify the dependence of right ventricular (RV) free wall longitudinal deformation on ventricular loading through segmental approach in relatively large number of patients with atrial septal defect (ASD). Methods Patients with ASD (n = 114) and age matched healthy children (n = 60) were echocardiographically examined the day before percutaneous device closure and within 24 hours afterwards. RV free wall deformation parameters, strain (?) and strain rate (SR), were analyzed in the apical (?A, SRA) and basal (?B, SRB) segments. Measured deformation parameters were adjusted for RV size (?AL, SRAL, ?BL, SRBL) by multiplying by body surface area indexed RV longitudinal dimension. Regression analyses determined the relationships of these deformation parameters with RV loading parameters that were measured by catheterization. Results ?BL and SRBL were not different between pre-closure patients and controls (p = 0.245, p = 0.866), and were decreased post-closure (p = 0.001, p = 0.018). Post-closure ?BL was lower than in controls (p = 0.001). Pre-closure ?AL and SRAL were higher than in controls (p = 0.001, p < 0.001), but decreased after closure (all p < 0.001). The pulmonary to systemic flow ratio was related to procedural differences of ?BL (p = 0.017) and of SRBL (p = 0.019). RV end diastolic pressure was negatively related to post-closure ?BL (p = 0.020) and post-closure SRBL (p = 0.012), and the procedural SRBL difference (p = 0.027). Conclusion The longitudinal deformation of the RV basal segment is dependent and its remodeling is also dependent on volume loading in children with ASD.

Ko, Hong Ki; Cho, Eun Kyung; Kang, So Yeon; Seo, Chang Deok; Baek, Jae Suk; Kim, Young-Hwue; Ko, Jae-Kon

2014-01-01

259

Automatic moment segmentation and peak detection analysis of heart sound pattern via short-time modified Hilbert transform.  

PubMed

This paper proposes a novel automatic method for the moment segmentation and peak detection analysis of heart sound (HS) pattern, with special attention to the characteristics of the envelopes of HS and considering the properties of the Hilbert transform (HT). The moment segmentation and peak location are accomplished in two steps. First, by applying the Viola integral waveform method in the time domain, the envelope (E(T)) of the HS signal is obtained with an emphasis on the first heart sound (S1) and the second heart sound (S2). Then, based on the characteristics of the E(T) and the properties of the HT of the convex and concave functions, a novel method, the short-time modified Hilbert transform (STMHT), is proposed to automatically locate the moment segmentation and peak points for the HS by the zero crossing points of the STMHT. A fast algorithm for calculating the STMHT of E(T) can be expressed by multiplying the E(T) by an equivalent window (W(E)). According to the range of heart beats and based on the numerical experiments and the important parameters of the STMHT, a moving window width of N=1s is validated for locating the moment segmentation and peak points for HS. The proposed moment segmentation and peak location procedure method is validated by sounds from Michigan HS database and sounds from clinical heart diseases, such as a ventricular septal defect (VSD), an aortic septal defect (ASD), Tetralogy of Fallot (TOF), rheumatic heart disease (RHD), and so on. As a result, for the sounds where S2 can be separated from S1, the average accuracies achieved for the peak of S1 (AP?), the peak of S2 (AP?), the moment segmentation points from S1 to S2 (AT??) and the cardiac cycle (ACC) are 98.53%, 98.31% and 98.36% and 97.37%, respectively. For the sounds where S1 cannot be separated from S2, the average accuracies achieved for the peak of S1 and S2 (AP??) and the cardiac cycle ACC are 100% and 96.69%. PMID:24657095

Sun, Shuping; Jiang, Zhongwei; Wang, Haibin; Fang, Yu

2014-05-01

260

A Rapid and Efficient 2D/3D Nuclear Segmentation Method for Analysis of Early Mouse Embryo and Stem Cell Image Data  

PubMed Central

Summary Segmentation is a fundamental problem that dominates the success of microscopic image analysis. In almost 25 years of cell detection software development, there is still no single piece of commercial software that works well in practice when applied to early mouse embryo or stem cell image data. To address this need, we developed MINS (modular interactive nuclear segmentation) as a MATLAB/C++-based segmentation tool tailored for counting cells and fluorescent intensity measurements of 2D and 3D image data. Our aim was to develop a tool that is accurate and efficient yet straightforward and user friendly. The MINS pipeline comprises three major cascaded modules: detection, segmentation, and cell position classification. An extensive evaluation of MINS on both 2D and 3D images, and comparison to related tools, reveals improvements in segmentation accuracy and usability. Thus, its accuracy and ease of use will allow MINS to be implemented for routine single-cell-level image analyses. PMID:24672759

Lou, Xinghua; Kang, Minjung; Xenopoulos, Panagiotis; Muñoz-Descalzo, Silvia; Hadjantonakis, Anna-Katerina

2014-01-01

261

Style, content and format guide for writing safety analysis documents. Volume 1, Safety analysis reports for DOE nuclear facilities  

SciTech Connect

The purpose of Volume 1 of this 4-volume style guide is to furnish guidelines on writing and publishing Safety Analysis Reports (SARs) for DOE nuclear facilities at Sandia National Laboratories. The scope of Volume 1 encompasses not only the general guidelines for writing and publishing, but also the prescribed topics/appendices contents along with examples from typical SARs for DOE nuclear facilities.

Not Available

1994-06-01

262

Coal gasification systems engineering and analysis. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

Feasibility analyses and systems engineering studies for a 20,000 tons per day medium Btu (MBG) coal gasification plant to be built by TVA in Northern Alabama were conducted. Major objectives were as follows: (1) provide design and cost data to support the selection of a gasifier technology and other major plant design parameters, (2) provide design and cost data to support alternate product evaluation, (3) prepare a technology development plan to address areas of high technical risk, and (4) develop schedules, PERT charts, and a work breakdown structure to aid in preliminary project planning. Volume one contains a summary of gasification system characterizations. Five gasification technologies were selected for evaluation: Koppers-Totzek, Texaco, Lurgi Dry Ash, Slagging Lurgi, and Babcock and Wilcox. A summary of the trade studies and cost sensitivity analysis is included.

1980-01-01

263

Oil-spill risk analysis: Cook inlet outer continental shelf lease sale 149. Volume 2: Conditional risk contour maps of seasonal conditional probabilities. Final report  

SciTech Connect

The Federal Government has proposed to offer Outer Continental Shelf (OCS) lands in Cook Inlet for oil and gas leasing. Because oil spills may occur from activities associated with offshore oil production, the Minerals Management Service conducts a formal risk assessment. In evaluating the significance of accidental oil spills, it is important to remember that the occurrence of such spills is fundamentally probabilistic. The effects of oil spills that could occur during oil and gas production must be considered. This report summarizes results of an oil-spill risk analysis conducted for the proposed Cook Inlet OCS Lease Sale 149. The objective of this analysis was to estimate relative risks associated with oil and gas production for the proposed lease sale. To aid the analysis, conditional risk contour maps of seasonal conditional probabilities of spill contact were generated for each environmental resource or land segment in the study area. This aspect is discussed in this volume of the two volume report.

Johnson, W.R.; Marshall, C.F.; Anderson, C.M.; Lear, E.M.

1994-08-01

264

Segmentation of thin section images for grain size analysis using region competition and edge-weighted region merging  

NASA Astrophysics Data System (ADS)

Microscopic thin section images are a major source of information on physical properties, crystallization processes, and the evolution of rocks. Extracting the boundaries of grains is of special interest for estimating the volumetric structure of sandstone. To deal with large datasets and to relieve the geologist from a manual analysis of images, automated methods are needed for the segmentation task. This paper evaluates the region competition framework, which also includes region merging. The procedure minimizes an energy functional based on the Minimum Description Length (MDL) principle. To overcome some known drawbacks of current algorithms, we present an extension of MDL-based region merging by integrating edge information between adjacent regions. In addition, we introduce a modified implementation for region competition for overcoming computational complexities when dealing with multiple competing regions. Commonly used methods are based on solving differential equations for describing the movement of boundaries, whereas our approach implements a simple updating scheme. Furthermore, we propose intensity features for reducing the amount of data. They are derived by comparing theoretical values obtained from a model function describing the intensity inside uniaxial crystals with measured data. Error, standard deviation, and phase shift between the model and intensity measurements preserve sufficient information for a proper segmentation. Additionally, identified objects are classified into quartz grains, anhydrite, and reaction fringes by these features. This grouping is, in turn, used to improve the segmentation process further. We illustrate the benefits of this approach by four samples of microscopic thin sections and quantify them in a comparison of a segmentation result and a manually obtained one.

Jungmann, Matthias; Pape, Hansgeorg; Wißkirchen, Peter; Clauser, Christoph; Berlage, Thomas

2014-11-01

265

Flow cytometric and karyological analysis of polysomaty and polyploidization during callus formation from leaf segments of various potato genotypes.  

PubMed

Flow cytometry and karyological analysis were used to study polysomaty and polyploidization during the first 15 days of callus formation in leaf segments from shoot cultures and greenhouse-grown plants of various lines and genotypes of Solanum tuberosum and S. phureja. The greenhouse-grown plants showed a higher degree of polysomaty (77% and 49% of polyploidized nuclei) than the shoot cultures (< 3%). During the in vitro culture period, polyploidization occurred through endoreduplication. Segments of the five shoot cultures showed up to 87%, 53%, 59%, 45% and 56% polyploidization, respectively; the DNA content of corresponding interphase nuclei amounted to 8C, 16C, 16C, 16C and 8C, and the chromosome numbers to 96. Segments from the two greenhouse-grown genotypes showed up to 87% and 84% polyploidization; the DNA content amounted to 32C and 16C, and the chromosome numbers to 192 and 96. The number of reduplication cycles was species-dependent; the degree of polyploidization was dependent on the initial ploidy level of the genotypes. Cell proliferation did not take place at a constant rate. The maximum frequencies of metaphases (52-171 per segment) occurred after 1 week of culture and were correlated with the ploidy level of the genotypes. Cells were triggered to mitosis rather than to endoreduplication. Cell cycles with normal monochromosomes could be shorter than 1 day, and those with diplochromosomes lasted at least 1 day. Polysomaty, degree of polyploidization and abnormal nuclear processes are discussed in relation to the origin of genetic instability early in culture. PMID:24232481

Pijnacker, L P; Sree Ramulu, K; Dijkhuis, P; Ferwerda, M A

1989-01-01

266

Modeling and analysis of passive dynamic bipedal walking with segmented feet and compliant joints  

NASA Astrophysics Data System (ADS)

Passive dynamic walking has been developed as a possible explanation for the efficiency of the human gait. This paper presents a passive dynamic walking model with segmented feet, which makes the bipedal walking gait more close to natural human-like gait. The proposed model extends the simplest walking model with the addition of flat feet and torsional spring based compliance on ankle joints and toe joints, to achieve stable walking on a slope driven by gravity. The push-off phase includes foot rotations around the toe joint and around the toe tip, which shows a great resemblance to human normal walking. This paper investigates the effects of the segmented foot structure on bipedal walking in simulations. The model achieves satisfactory walking results on even or uneven slopes.

Huang, Yan; Wang, Qi-Ning; Gao, Yue; Xie, Guang-Ming

2012-10-01

267

Shape-Constrained Segmentation Approach for Arctic Multiyear Sea Ice Floe Analysis  

NASA Technical Reports Server (NTRS)

The melting of sea ice is correlated to increases in sea surface temperature and associated climatic changes. Therefore, it is important to investigate how rapidly sea ice floes melt. For this purpose, a new Tempo Seg method for multi temporal segmentation of multi year ice floes is proposed. The microwave radiometer is used to track the position of an ice floe. Then,a time series of MODIS images are created with the ice floe in the image center. A Tempo Seg method is performed to segment these images into two regions: Floe and Background.First, morphological feature extraction is applied. Then, the central image pixel is marked as Floe, and shape-constrained best merge region growing is performed. The resulting tworegionmap is post-filtered by applying morphological operators.We have successfully tested our method on a set of MODIS images and estimated the area of a sea ice floe as afunction of time.

Tarabalka, Yuliya; Brucker, Ludovic; Ivanoff, Alvaro; Tilton, James C.

2013-01-01

268

Design and Analysis of Modules for Segmented X-Ray Optics  

NASA Technical Reports Server (NTRS)

Future X-ray astronomy missions demand thin, light, and closely packed optics which lend themselves to segmentation of the annular mirrors and, in turn, a modular approach to the mirror design. The modular approach to X-ray Flight Mirror Assembly (FMA) design allows excellent scalability of the mirror technology to support a variety of mission sizes and science objectives. This paper describes FMA designs using slumped glass mirror segments for several X-ray astrophysics missions studied by NASA and explores the driving requirements and subsequent verification tests necessary to qualify a slumped glass mirror module for space-flight. A rigorous testing program is outlined allowing Technical Development Modules to reach technical readiness for mission implementation while reducing mission cost and schedule risk.

McClelland, Ryan S.; BIskach, Michael P.; Chan, Kai-Wing; Saha, Timo T; Zhang, William W.

2012-01-01

269

Spatial Sampling for Image Segmentation  

E-print Network

Spatial Sampling for Image Segmentation MARIANO RIVERA1 , OSCAR DALMAU1 , WASHINGTON MIO2 in interactive image segmentation, automatic stereo analysis, and denoising of brain water diffusion multi-tensor fields demonstrate the capabilities of our approach. Keywords: Image segmentation, Early computer vision

Rivera, Mariano

270

Sensitivity field distributions for segmental bioelectrical impedance analysis based on real human anatomy  

NASA Astrophysics Data System (ADS)

In this work, an adaptive unstructured tetrahedral mesh generation technology is applied for simulation of segmental bioimpedance measurements using high-resolution whole-body model of the Visible Human Project man. Sensitivity field distributions for a conventional tetrapolar, as well as eight- and ten-electrode measurement configurations are obtained. Based on the ten-electrode configuration, we suggest an algorithm for monitoring changes in the upper lung area.

Danilov, A. A.; Kramarenko, V. K.; Nikolaev, D. V.; Rudnev, S. G.; Salamatova, V. Yu; Smirnov, A. V.; Vassilevski, Yu V.

2013-04-01

271

Quantitative morphological analysis of curvilinear network for microscopic image based on individual fibre segmentation (IFS).  

PubMed

Microscopic images of curvilinear fibre network structure like cytoskeleton are traditionally analysed by qualitative observation, which can hardly provide quantitative information of their morphological properties. However, such information is crucially contributive to the understanding of important biological events, even helps to learn about the inner relations hard to perceive. Individual fibre segmentation-based curvilinear structure detector proposed in this study can identify each individual fibre in the network, as well as connections between different fibres. Quantitative information of each individual fibre, including length, orientation and position, can be extracted; so are the connecting modes in the fibre network, such as bifurcation, intersection and overlap. Distribution of fibres with different morphological properties is also presented. No manual intervening or subjective judging is required in the analysing process. Both synthesized and experimental microscopic images have verified that the detector is capable to segment curvilinear network at the subcellular level with strong noise immunity. The proposed detector is finally applied to the morphological study on cytoskeleton. It is believed that the individual fibre segmentation-based curvilinear structure detector can greatly enhance our understanding of those biological images generated from tons of biological experiments. PMID:25243901

Qiu, J; Li, F-F

2014-12-01

272

On the development of weighting factors for ballast ranking prioritization & development of the relationship and rate of defective segments based on volume of missing ballast  

NASA Astrophysics Data System (ADS)

This thesis explores the effects of missing ballast on track behavior and degradation. As ballast is an integral part of the track structure, the hypothesized effect of missing ballast is that defects will be more common which in turn leads to more derailments. In order to quantify the volume of missing ballast, remote sensing technologies were used to provide an accurate profile of the ballast. When the existing profile is compared to an idealized profile, the area of missing ballast can be computed. The area is then subdivided into zones which represent the area in which the ballast performs a key function in the track structure. These areas are then extrapolated into the volume of missing ballast for each zone based on the distance between collected profiles. In order to emphasize the key functions that the zones previously created perform, weighting factors were developed based on common risk-increasing hazards, such as curves and heavy axle loads, which are commonly found on railways. These weighting factors are applied to the specified zones' missing ballast volume when such a hazard exists in that segment of track. Another set of weighting factors were developed to represent the increased risk, or preference for lower risk, for operational factors such as the transport of hazardous materials or for being a key route. Through these weighting factors, ballast replenishment can be prioritized to focus on the areas that pose a higher risk of derailments and their associated costs. For the special cases where the risk or aversion to risk comes from what is being transported, such as the case with hazardous materials or passengers, an economic risk assessment was completed in order to quantify the risk associated with their transport. This economic risk assessment looks at the increased costs associated with incidents that occur and how they compare to incidents which do not directly involve the special cargos. In order to provide support for the use of the previously developed weightings as well as to quantify the actual impact that missing ballast has on the rate of geometry defects, analyses which quantified the risk of missing ballast were performed. In addition to quantifying the rate of defects, analyses were performed which looked at the impact associated with curved track, how the location of missing ballast impacts the rate of geometry defects and how the combination of the two compared with the previous analyses. Through this research, the relationship between the volume of missing ballast and ballast-related defects has been identified and quantified. This relationship is positive for the aggregate of all ballast-related defects but does not always exist for individual defects which occasionally have unique behavior. For the non-ballast defects, a relationship between missing ballast and their rate of occurrence did not always appear to exist. The impact of curves was apparent, showing that the rate of defects was either similar to or exceeded the rate of defects for tangent track. For the analyses which looked at the location of ballast in crib or shoulder, the results were quite similar to the previous analyses. The development, application and improvements of a risk-based ballast maintenance prioritization system provides a relatively low-cost and effective method to improve the operational safety for all railroads.

Cronin, John

273

A computer program for comprehensive ST-segment depression/heart rate analysis of the exercise ECG test.  

PubMed

The ST-segment depression/heart rate (ST/HR) analysis has been found to improve the diagnostic accuracy of the exercise ECG test in detecting myocardial ischemia. Recently, three different continuous diagnostic variables based on the ST/HR analysis have been introduced; the ST/HR slope, the ST/HR index and the ST/HR hysteresis. The latter utilises both the exercise and recovery phases of the exercise ECG test, whereas the two former are based on the exercise phase only. This present article presents a computer program which not only calculates the above three diagnostic variables but also plots the full diagrams of ST-segment depression against heart rate during both exercise and recovery phases for each ECG lead from given ST/HR data. The program can be used in the exercise ECG diagnosis of daily clinical practice provided that the ST/HR data from the ECG measurement system can be linked to the program. At present, the main purpose of the program is to provide clinical and medical researchers with a practical tool for comprehensive clinical evaluation and development of the ST/HR analysis. PMID:8835841

Lehtinen, R; Vänttinen, H; Sievänen, H; Malmivuo, J

1996-06-01

274

MR image segmentation using vector decomposition and probability techniques: a general model and its application to dual-echo images.  

PubMed

A general model is developed for segmenting magnetic resonance images using vector decomposition and probability techniques. Each voxel is assigned fractional volumes of q tissues from p differently weighted images (q < or = p + 1) in the presence of partial-volume mixing, random noise, and other tissues. Compared with the eigenimage method, fewer differently weighted images are needed for segmenting the q tissues, and the contrast-to-noise ratio in the calculated fractional volumes is improved. The model can produce composite tissue-type images similar to that of the probability methods, by comparing the fractional volumes assigned to different tissues on each voxel. A three-tissue (p = 2, q = 3) model is illustrated for segmenting three tissues from dual-echo images. It provides statistical analysis to the algebraic method. A three-compartment phantom is segmented for validation. Two clinical examples are presented. PMID:8771029

Kao, Y H; Sorenson, J A; Winkler, S S

1996-01-01

275

3D digital cleansing using segmentation rays  

Microsoft Academic Search

We propose a novel approach for segmentation and digital cle ans- ing of endoscopic organs. Our method can be used for a variety of segmentation needs with little or no modification. It aimsat fulfilling the dual and often conflicting requirements of a fast and accurate segmentation and also eliminates the undesirable partial volume effect which contemporary approaches cannot. For se

Sarang Lakare; Ming Wan; Mie Sato; Arie E. Kaufman

2000-01-01

276

Carbon Prices during the EU ETS Phase II: Dynamics and Volume Analysis  

E-print Network

1 Carbon Prices during the EU ETS Phase II: Dynamics and Volume Analysis Julien Chevallier1, and details the carbon price dynamics during Phase II (2008-2012), along with an analysis of traded volumes in the medium-term in integrated `world' carbon markets between various regional and/or national ETS. Keywords

Boyer, Edmond

277

Segmentation and detection of breast cancer in mammograms combining wavelet analysis and genetic algorithm.  

PubMed

In Brazil, the National Cancer Institute (INCA) reports more than 50,000 new cases of the disease, with risk of 51 cases per 100,000 women. Radiographic images obtained from mammography equipments are one of the most frequently used techniques for helping in early diagnosis. Due to factors related to cost and professional experience, in the last two decades computer systems to support detection (Computer-Aided Detection - CADe) and diagnosis (Computer-Aided Diagnosis - CADx) have been developed in order to assist experts in detection of abnormalities in their initial stages. Despite the large number of researches on CADe and CADx systems, there is still a need for improved computerized methods. Nowadays, there is a growing concern with the sensitivity and reliability of abnormalities diagnosis in both views of breast mammographic images, namely cranio-caudal (CC) and medio-lateral oblique (MLO). This paper presents a set of computational tools to aid segmentation and detection of mammograms that contained mass or masses in CC and MLO views. An artifact removal algorithm is first implemented followed by an image denoising and gray-level enhancement method based on wavelet transform and Wiener filter. Finally, a method for detection and segmentation of masses using multiple thresholding, wavelet transform and genetic algorithm is employed in mammograms which were randomly selected from the Digital Database for Screening Mammography (DDSM). The developed computer method was quantitatively evaluated using the area overlap metric (AOM). The mean ± standard deviation value of AOM for the proposed method was 79.2 ± 8%. The experiments demonstrate that the proposed method has a strong potential to be used as the basis for mammogram mass segmentation in CC and MLO views. Another important aspect is that the method overcomes the limitation of analyzing only CC and MLO views. PMID:24513228

Pereira, Danilo Cesar; Ramos, Rodrigo Pereira; do Nascimento, Marcelo Zanchetta

2014-04-01

278

Functional analysis of centipede development supports roles for Wnt genes in posterior development and segment generation.  

PubMed

The genes of the Wnt family play important and highly conserved roles in posterior growth and development in a wide range of animal taxa. Wnt genes also operate in arthropod segmentation, and there has been much recent debate regarding the relationship between arthropod and vertebrate segmentation mechanisms. Due to its phylogenetic position, body form, and possession of many (11) Wnt genes, the centipede Strigamia maritima is a useful system with which to examine these issues. This study takes a functional approach based on treatment with lithium chloride, which causes ubiquitous activation of canonical Wnt signalling. This is the first functional developmental study performed in any of the 15,000 species of the arthropod subphylum Myriapoda. The expression of all 11 Wnt genes in Strigamia was analyzed in relation to posterior development. Three of these genes, Wnt11, Wnt5, and WntA, were strongly expressed in the posterior region and, thus, may play important roles in posterior developmental processes. In support of this hypothesis, LiCl treatment of S. maritima embryos was observed to produce posterior developmental defects and perturbations in AbdB and Delta expression. The effects of LiCl differ depending on the developmental stage treated, with more severe effects elicited by treatment during germband formation than by treatment at later stages. These results support a role for Wnt signalling in conferring posterior identity in Strigamia. In addition, data from this study are consistent with the hypothesis of segmentation based on a "clock and wavefront" mechanism operating in this species. PMID:25627713

Hayden, Luke; Schlosser, Gerhard; Arthur, Wallace

2015-01-01

279

Comparing Market-segment-profitability Analysis with Department-Profitability Analysis as Hotel Marketing-decision Tools  

Microsoft Academic Search

Although marketing managers would appreciate financial data that more directly support their activities, the financial data generated by hotel accounting systems are aimed at apportioning department-related expenses and reflecting financial picture of overall operation. Given the industry’s increased focus on the profit generated by a given customer or market segment, a more useful form of financial data would allow hotel

Islam Karadag; Woo Gon Kim

2006-01-01

280

A Posteriori Error Analysis of a Cell-centered Finite Volume Method for Semilinear Elliptic Problems  

SciTech Connect

In this paper, we conduct an a posteriori analysis for the error in a quantity of interest computed from a cell-centered finite volume scheme. The a posteriori error analysis is based on variational analysis, residual error and the adjoint problem. To carry out the analysis, we use an equivalence between the cell-centered finite volume scheme and a mixed finite element method with special choice of quadrature.

Michael Pernice

2009-11-01

281

Air segmented amplitude modulated multiplexed flow analysis with software-based phase recognition: determination of phosphate ion.  

PubMed

Amplitude modulated multiplexed flow analysis (AMMFA) has been improved by introducing air segmentation and software-based phase recognition. Sample solutions, the flow rates of which are respectively varied at different frequencies, are merged. Air is introduced to the merged liquid stream in order to limit the dispersion of analytes within each liquid segment separated by air bubbles. The stream is led to a detector with no physical deaeration. Air signals are distinguished from liquid signals through the analysis of detector output signals, and are suppressed down to the level of liquid signals. Resulting signals are smoothed based on moving average computation. Thus processed signals are analyzed by fast Fourier transform. The analytes in the samples are respectively determined from the amplitudes of the corresponding wave components obtained. The developed system has been applied to the simultaneous determinations of phosphate ions in water samples by a Malachite Green method. The linearity of the analytical curve (0.0-31.0 ?mol dm(-3)) is good (r(2)>0.999) and the detection limit (3.3 ?) at the modulation period of 30s is 0.52 ?mol dm(-3). Good recoveries around 100% have been obtained for phosphate ions spiked into real water samples. PMID:24274279

Ogusu, Takeshi; Uchimoto, Katsuya; Takeuchi, Masaki; Tanaka, Hideji

2014-01-01

282

A genetic analysis of brain volumes and IQ in children  

Microsoft Academic Search

In a population-based sample of 112 nine-year old twin pairs, we investigated the association among total brain volume, gray matter and white matter volume, intelligence as assessed by the Raven IQ test, verbal comprehension, perceptual organization and perceptual speed as assessed by the Wechsler Intelligence Scale for Children-III. Phenotypic correlations between the brain volumes and intelligence traits ranged between .20

Marieke van Leeuwen; Jiska S. Peper; Stéphanie M. van den Berg; Rachel M. Brouwer; Hilleke E. Hulshoff Pol; René S. Kahn; Dorret I. Boomsma

2009-01-01

283

Analysis on the use of Multi-Sequence MRI Series for Segmentation of Abdominal Organs  

NASA Astrophysics Data System (ADS)

Segmentation of abdominal organs from MRI data sets is a challenging task due to various limitations and artefacts. During the routine clinical practice, radiologists use multiple MR sequences in order to analyze different anatomical properties. These sequences have different characteristics in terms of acquisition parameters (such as contrast mechanisms and pulse sequence designs) and image properties (such as pixel spacing, slice thicknesses and dynamic range). For a complete understanding of the data, computational techniques should combine the information coming from these various MRI sequences. These sequences are not acquired in parallel but in a sequential manner (one after another). Therefore, patient movements and respiratory motions change the position and shape of the abdominal organs. In this study, the amount of these effects is measured using three different symmetric surface distance metrics performed to three dimensional data acquired from various MRI sequences. The results are compared to intra and inter observer differences and discussions on using multiple MRI sequences for segmentation and the necessities for registration are presented.

Selver, M. A.; Selvi, E.; Kavur, E.; Dicle, O.

2015-01-01

284

Phylogenetic analysis, genomic diversity and classification of M class gene segments of turkey reoviruses.  

PubMed

From 2011 to 2014, 13 turkey arthritis reoviruses (TARVs) were isolated from cases of swollen hock joints in 2-18-week-old turkeys. In addition, two isolates from similar cases of turkey arthritis were received from another laboratory. Eight turkey enteric reoviruses (TERVs) isolated from fecal samples of turkeys were also used for comparison. The aims of this study were to characterize turkey reovirus (TRV) based on complete M class genome segments and to determine genetic diversity within TARVs in comparison to TERVs and chicken reoviruses (CRVs). Nucleotide (nt) cut off values of 84%, 83% and 85% for the M1, M2 and M3 gene segments were proposed and used for genotype classification, generating 5, 7, and 3 genotypes, respectively. Using these nt cut off values, we propose M class genotype constellations (GCs) for avian reoviruses. Of the seven GCs, GC1 and GC3 were shared between the TARVs and TERVs, indicating possible reassortment between turkey and chicken reoviruses. The TARVs and TERVs were divided into three GCs, and GC2 was unique to TARVs and TERVs. The proposed new GC approach should be useful in identifying reassortant viruses, which may ultimately be used in the design of a universal vaccine against both chicken and turkey reoviruses. PMID:25655814

Mor, Sunil K; Marthaler, Douglas; Verma, Harsha; Sharafeldin, Tamer A; Jindal, Naresh; Porter, Robert E; Goyal, Sagar M

2015-03-23

285

Probabilistic analysis of activation volumes generated during deep brain stimulation.  

PubMed

Deep brain stimulation (DBS) is an established therapy for the treatment of Parkinson's disease (PD) and shows great promise for the treatment of several other disorders. However, while the clinical analysis of DBS has received great attention, a relative paucity of quantitative techniques exists to define the optimal surgical target and most effective stimulation protocol for a given disorder. In this study we describe a methodology that represents an evolutionary addition to the concept of a probabilistic brain atlas, which we call a probabilistic stimulation atlas (PSA). We outline steps to combine quantitative clinical outcome measures with advanced computational models of DBS to identify regions where stimulation-induced activation could provide the best therapeutic improvement on a per-symptom basis. While this methodology is relevant to any form of DBS, we present example results from subthalamic nucleus (STN) DBS for PD. We constructed patient-specific computer models of the volume of tissue activated (VTA) for 163 different stimulation parameter settings which were tested in six patients. We then assigned clinical outcome scores to each VTA and compiled all of the VTAs into a PSA to identify stimulation-induced activation targets that maximized therapeutic response with minimal side effects. The results suggest that selection of both electrode placement and clinical stimulation parameter settings could be tailored to the patient's primary symptoms using patient-specific models and PSAs. PMID:20974269

Butson, Christopher R; Cooper, Scott E; Henderson, Jaimie M; Wolgamuth, Barbara; McIntyre, Cameron C

2011-02-01

286

Multiresolution Medical Image Segmentation Based on Wavelet Transform  

Microsoft Academic Search

The wavelet transform always is used to analyze image. The watershed transformation is a useful morphological segmentation tool for a variety of grey-scale image. In this paper, an efficient segmentation method for medical image analysis is presented, which combines pyramidal image segmentation with hierarchical watershed segmentation algorithm. The segmentation procedure consists of pyramid representation, image segmentation, region merging and region

Haihua Liu; Zhouhui Chen; Xinhao Chen; Yaguang Chen

2005-01-01

287

Analysis of flexible aircraft longitudinal dynamics and handling qualities. Volume 1: Analysis methods  

NASA Technical Reports Server (NTRS)

As aircraft become larger and lighter due to design requirements for increased payload and improved fuel efficiency, they will also become more flexible. For highly flexible vehicles, the handling qualities may not be accurately predicted by conventional methods. This study applies two analysis methods to a family of flexible aircraft in order to investigate how and when structural (especially dynamic aeroelastic) effects affect the dynamic characteristics of aircraft. The first type of analysis is an open loop model analysis technique. This method considers the effects of modal residue magnitudes on determining vehicle handling qualities. The second method is a pilot in the loop analysis procedure that considers several closed loop system characteristics. Volume 1 consists of the development and application of the two analysis methods described above.

Waszak, M. R.; Schmidt, D. S.

1985-01-01

288

Segmental hair analysis for 11-nor-??-tetrahydrocannabinol-9-carboxylic acid and the patterns of cannabis use.  

PubMed

Cannabis is the most widely abused drug in the world. The purpose of this study is to detect 11-nor-9-carboxy-??-tetrahydrocannabinol (THCCOOH) in segmental hair and to evaluate the patterns of cannabis use. We investigated the relationship between the concentrations of THCCOOH in hair and the self-reported use data and the route of administration. For this purpose, the hair samples were washed, digested with 1 mL of 1 M NaOH at 85°C for 30 min along with the internal standard, THCCOOH-d? (2.5 pg/mg) and extracted in 2 mL of n-hexane-ethyl acetate (9:1) twice after adding 1 mL of 0.1N sodium acetate buffer (pH = 4.5) and 200 µL of acetic acid. The organic extract was transferred and evaporated and the mixture was derivatized with 50 µL of pentafluoropropionic anhydride and 25 µL of pentafluoropropanol for 30 min at 70°C. Reconstituted final extract was injected into the gas chromatography-tandem mass spectrometer operating in the negative chemical ionization mode. In segmental hair analysis, the concentrations of THCCOOH decreased from the proximal to distal segments. The concentrations of THCCOOH in hair and the self-reported dose and frequency of administration from cannabis users were not well correlated because of the low accuracy and reliability of the self-reported data. However, this study provides preliminary information on the dose and frequency of administration among cannabis users in our country. PMID:22417835

Han, Eunyoung; Chung, Heesun; Song, Joon Myong

2012-04-01

289

Determination of fiber volume in graphite/epoxy materials using computer image analysis  

NASA Technical Reports Server (NTRS)

The fiber volume of graphite/epoxy specimens was determined by analyzing optical images of cross sectioned specimens using image analysis software. Test specimens were mounted and polished using standard metallographic techniques and examined at 1000 times magnification. Fiber volume determined using the optical imaging agreed well with values determined using the standard acid digestion technique. The results were found to agree within 5 percent over a fiber volume range of 45 to 70 percent. The error observed is believed to arise from fiber volume variations within the graphite/epoxy panels themselves. The determination of ply orientation using image analysis techniques is also addressed.

Viens, Michael J.

1990-01-01

290

One year follow-up after operative ankle fractures: a prospective gait analysis study with a multi-segment foot model.  

PubMed

Ankle fractures are one of the most common lower limb traumas. Several studies reported short- and long-term post-operative results, mainly determined by radiographic and subjective functional evaluations. Three-dimensional gait analysis with a multi-segment foot model was used in the current study to quantify the inter-segment foot motions in 18 patients 1 year after surgically treated ankle fractures. Data were compared to that from gender- and age-matched healthy controls. The correlations between Olerud/Molander ankle score and kinematics were also evaluated. Patients with ankle fractures showed less plantarflexion and smaller range of motion in the injured talocrural joint, which were believed to be a sign of residual joint stiffness after surgery and immobilization. Moreover, the forefoot segment had smaller sagittal and transverse ranges of motion, less plantarflexion and the hallux segment had less dorsiflexion and smaller sagittal range of motion. The deviations found in the forefoot segment may contribute to the compensation mechanisms of the injured ankle joint. Findings of our study show that gait analysis with a multi-segment foot model provides a quantitative and objective way to perform the dynamic assessment of post-operative ankle fractures, and makes it possible to better understand not only how the injured joint is affected, but also the surrounding joints. PMID:19942435

Wang, Ruoli; Thur, Charlotte K; Gutierrez-Farewik, Elena M; Wretenberg, Per; Broström, Eva

2010-02-01

291

EPA RREL'S MOBILE VOLUME REDUCTION UNIT -- APPLICATIONS ANALYSIS REPORT  

EPA Science Inventory

The volume reduction unit (VRU) is a pilot-scale, mobile soil washing system designed to remove organic contaminants from the soil through particle size separation and solubilization. The VRU removes contaminants by suspending them in a wash solution and by reducing the volume of...

292

Fractal Analysis of Laplacian Pyramidal Filters Applied to Segmentation of Soil Images  

PubMed Central

The laplacian pyramid is a well-known technique for image processing in which local operators of many scales, but identical shape, serve as the basis functions. The required properties to the pyramidal filter produce a family of filters, which is unipara metrical in the case of the classical problem, when the length of the filter is 5. We pay attention to gaussian and fractal behaviour of these basis functions (or filters), and we determine the gaussian and fractal ranges in the case of single parameter a. These fractal filters loose less energy in every step of the laplacian pyramid, and we apply this property to get threshold values for segmenting soil images, and then evaluate their porosity. Also, we evaluate our results by comparing them with the Otsu algorithm threshold values, and conclude that our algorithm produce reliable test results. PMID:25114957

de Castro, J.; Méndez, A.; Tarquis, A. M.

2014-01-01

293

Transient ischemic stunning of the myocardium in stress thallium-201 gated SPET myocardial perfusion imaging: segmental analysis of myocardial perfusion, wall motion and wall thickening changes.  

PubMed

Prolonged and persistent myocardial stunning has recently been demonstrated using technetium-99m sestamibi gated single-photon emission tomography (SPET) myocardial perfusion imaging post exercise or pharmacological stress test. In this study, we investigated the early postischemic transient myocardial stunning on early and delayed poststress thallium-201 gated SPET myocardial perfusion imaging using segmental wall motion (WM) and wall thickening (WT) analysis. A total of 1,680 segments from 84 patients' studies (53 men and 31 women, mean age 60 years) were evaluated on both early and delayed thallium-201 gated SPET treadmill exercise (59) or dobutamine stress (25) myocardial perfusion imaging. Semiquantitative analysis of perfusion, WM and WT in all segments was performed by two observers. Segments were classified according to changes in WM and WT between early and delayed images into normal, fixed abnormality, or improved abnormality (transient stunning), and were further classified according to changes in perfusion into normal, fixed defects, or ischemic. There were significant correlations between perfusion and WM, perfusion and WT, and WM and WT segmental scores on both early and delayed images. Transient stunning was seen significantly ( P < 0.001) more often in ischemic segments than were normal or fixed perfusion defects using WM (58%) and WT (50%) assessments. There was also a significant correlation between the severity of ischemia and transient stunning with either WM ( P < 0.05) or WT ( P < 0.005) evaluation. Segmental myocardial contractility assessment from gated SPET (201)Tl myocardial perfusion imaging using WM and WT was comparable, and results correlated well with the myocardial perfusion assessment. Early transient myocardial stunning was frequently observed in ischemic segments and was related to the severity of myocardial ischemia. PMID:12173009

Santiago, Jonas Francisco Y; Heiba, Sherif I; Jana, Suman; Mirzaitehrane, Majid; Dede, Fuat; Abdel-Dayem, Hussein M

2002-08-01

294

A link-segment model of upright human posture for analysis of head-trunk coordination  

NASA Technical Reports Server (NTRS)

Sensory-motor control of upright human posture may be organized in a top-down fashion such that certain head-trunk coordination strategies are employed to optimize visual and/or vestibular sensory inputs. Previous quantitative models of the biomechanics of human posture control have examined the simple case of ankle sway strategy, in which an inverted pendulum model is used, and the somewhat more complicated case of hip sway strategy, in which multisegment, articulated models are used. While these models can be used to quantify the gross dynamics of posture control, they are not sufficiently detailed to analyze head-trunk coordination strategies that may be crucial to understanding its underlying mechanisms. In this paper, we present a biomechanical model of upright human posture that extends an existing four mass, sagittal plane, link-segment model to a five mass model including an independent head link. The new model was developed to analyze segmental body movements during dynamic posturography experiments in order to study head-trunk coordination strategies and their influence on sensory inputs to balance control. It was designed specifically to analyze data collected on the EquiTest (NeuroCom International, Clackamas, OR) computerized dynamic posturography system, where the task of maintaining postural equilibrium may be challenged under conditions in which the visual surround, support surface, or both are in motion. The performance of the model was tested by comparing its estimated ground reaction forces to those measured directly by support surface force transducers. We conclude that this model will be a valuable analytical tool in the search for mechanisms of balance control.

Nicholas, S. C.; Doxey-Gasway, D. D.; Paloski, W. H.

1998-01-01

295

Applications of MR Image Segmentation  

Microsoft Academic Search

After the introduction of digital imaging devices in medicine computerized tissue recognition and classification (i.e., segmentation) have become important in research and clinical applications. Segmented data can be applied among numerous research fields including volumetric analysis of particular tissues and structures, construction of anatomical models, three-dimensional (3D) visualization, and multimodal visualization, hence making segmentation essential in modern image analysis. In

Tomi Heinonen; Prasun Dastidar; Harry Frey; Hannu Eskola

296

Body composition in heavy smokers: comparison of segmental bioelectrical impedance analysis and dual-energy x-ray absorptiometry.  

PubMed

Smokers tend to have lower body mass index, on one hand, and increased abdominal obesity, on the other hand. Also, low levels of lean mass (LM) and bone mineral content (BMC) were found among older smokers compared with non-smokers. This altered body composition and its consequences raise the need for simple and reliable methods for assessment of body composition in smokers. This study aimed to compare body composition assessment by segmental bioelectrical impedance analysis (sBIA) with the reference method, dual energy X-ray absorptiometry (DEXA). Body composition was measured by sBIA (Tanita BC-545) and DEXA (Hologic) in 49 heavy smokers (>15 cigarettes/day, mean age 43.8?±?12.0). The comparison included correlations and differences between measurements obtained using the two methods as well as the Blande-Altman analysis. Whole-body fat mass (FM) and LM measured by the two methods were found to be highly correlated (r?>?0.9, p?analysis revealed a good agreement for whole-body FM and LM, but a poor agreement for BMC. The segmental FM percentage and LM were also highly correlated (r?>?0.9, p?

Rom, O; Reznick, A Z; Keidar, Z; Karkabi, K; Aizenbud, D

2015-01-01

297

Cargo Logistics Airlift Systems Study (CLASS). Volume 1: Analysis of current air cargo system  

NASA Technical Reports Server (NTRS)

The material presented in this volume is classified into the following sections; (1) analysis of current routes; (2) air eligibility criteria; (3) current direct support infrastructure; (4) comparative mode analysis; (5) political and economic factors; and (6) future potential market areas. An effort was made to keep the observations and findings relating to the current systems as objective as possible in order not to bias the analysis of future air cargo operations reported in Volume 3 of the CLASS final report.

Burby, R. J.; Kuhlman, W. H.

1978-01-01

298

Urinary bladder segmentation in CT urography (CTU) using CLASS  

PubMed Central

Purpose: The authors are developing a computerized system for bladder segmentation on CTU, as a critical component for computer aided diagnosis of bladder cancer. Methods: A challenge for bladder segmentation is the presence of regions without contrast (NC) and filled with intravenous contrast (C). The authors have designed a Conjoint Level set Analysis and Segmentation System (CLASS) specifically for this application. CLASS performs a series of image processing tasks: preprocessing, initial segmentation, 3D and 2D level set segmentation, and postprocessing, designed according to the characteristics of the bladder in CTU. The NC and the C regions of the bladder were segmented separately in CLASS. The final contour is obtained in the postprocessing stage by the union of the NC and C contours. With Institutional Review Board (IRB) approval, the authors retrospectively collected 81 CTU scans, in which 40 bladders contained lesions, 26 contained diffuse wall thickening, and 15 were considered to be normal. The bladders were segmented by CLASS and the performance was assessed by rating the quality of the contours on a 10-point scale (1 = “very poor,” 5 = “fair,” 10 = “perfect”). For 30 bladders, 3D hand-segmented contours were obtained and the segmentation accuracy of CLASS was evaluated and compared to that of a single level set method in terms of the average minimum distance, average volume intersection ratio, average volume error and Jaccard index. Results: Of the 81 bladders, the average quality rating for CLASS was 6.5 ± 1.3. Thirty nine bladders were given quality ratings of 7 or above. Only five bladders had ratings under 5. The average minimum distance, average volume intersection ratio, average volume error, and average Jaccard index for CLASS were 3.5 ± 1.3 mm, (79.0 ± 8.2)%, (16.1 ± 16.3)%, and (75.7 ± 8.4)%, respectively, and for the single level set method were 5.2 ± 2.6 mm, (78.8 ± 16.3)%, (8.3 ± 33.1)%, (71.0 ± 15.4)%, respectively. Conclusions: The results demonstrate the potential of CLASS for segmentation of the bladder. PMID:24320439

Hadjiiski, Lubomir; Chan, Heang-Ping; Cohan, Richard H.; Caoili, Elaine M.; Law, Yuen; Cha, Kenny; Zhou, Chuan; Wei, Jun

2013-01-01

299

A registration-based segmentation method with application to adiposity analysis of mice microCT images  

NASA Astrophysics Data System (ADS)

Obesity is a global health problem, particularly in the U.S. where one third of adults are obese. A reliable and accurate method of quantifying obesity is necessary. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) are two measures of obesity that reflect different associated health risks, but accurate measurements in humans or rodent models are difficult. In this paper we present an automatic, registration-based segmentation method for mouse adiposity studies using microCT images. We co-register the subject CT image and a mouse CT atlas. Our method is based on surface matching of the microCT image and an atlas. Surface-based elastic volume warping is used to match the internal anatomy. We acquired a whole body scan of a C57BL6/J mouse injected with contrast agent using microCT and created a whole body mouse atlas by manually delineate the boundaries of the mouse and major organs. For method verification we scanned a C57BL6/J mouse from the base of the skull to the distal tibia. We registered the obtained mouse CT image to our atlas. Preliminary results show that we can warp the atlas image to match the posture and shape of the subject CT image, which has significant differences from the atlas. We plan to use this software tool in longitudinal obesity studies using mouse models.

Bai, Bing; Joshi, Anand; Brandhorst, Sebastian; Longo, Valter D.; Conti, Peter S.; Leahy, Richard M.

2014-04-01

300

Interactive Exploration and Analysis of Large Scale Simulations Using Topology-based Data Segmentation  

E-print Network

Interactive Exploration and Analysis of Large Scale Simulations Using Topology-based Data and engineering phenomena. As a result, advanced visualization and data analysis are also becoming an integral such a characterization will help to evaluate the conclusions of the analysis as a whole. We present a new topological

Tierny, Julien

301

Cell Based Volume Integration for Boundary Integral Analysis  

SciTech Connect

The evaluation of volume integrals that arise in boundary integral formulations for non-homogeneous problems is considered. Using the 'Galerkin vector' to represent the Green's function, the volume integral is decomposed into a boundary integral plus a simpler volume integral wherein the source function is everywhere zero on the boundary. This new volume integral can be evaluated using a regular grid of cells covering the domain, with all cell integrals, including partial cells at the boundary, evaluated by simple linear interpolation of vertex values. For grid vertices that lie close to the boundary, the near-singular integrals are handled by partial analytic integration. The method employs a Galerkin approximation and is presented in terms of the 3D Poisson problem. An axi-symmetric formulation is also presented, and in this setting, the solution of a nonlinear problem is considered.

Koehler, Matthew [Vanderbilt University; Yang, Ruoke [ORNL; Gray, Leonard J [ORNL

2012-01-01

302

COAL CONVERSION CONTROL TECHNOLOGY. VOLUME III. ECONOMIC ANALYSIS; APPENDIX  

EPA Science Inventory

This volume is the product of an information-gathering effort relating to coal conversion process streams. Available and developing control technology has been evaluated in view of the requirements of present and proposed federal, state, regional, and international environmental ...

303

PREDICTION OF MINERAL QUALITY OF IRRIGATION RETURN FLOW. VOLUME IV. DATA ANALYSIS UTILITY PROGRAMS  

EPA Science Inventory

This volume of the report contains a description of the data analysis subroutines developed to support the modeling effort described in Volume III. The subroutines were used to evaluate and condition data used in the conjunctive use model. The subroutines include (1) regression a...

304

A STANDARD PROCEDURE FOR COST ANALYSIS OF POLLUTION CONTROL OPERATIONS. VOLUME II. APPENDICES  

EPA Science Inventory

Volume I is a user guide for a standard procedure for the engineering cost analysis of pollution abatement operations and processes. The procedure applies to projects in various economic sectors: private, regulated, and public. Volume II, the bulk of the document, contains 11 app...

305

Image-based segmentation for characterization and quantitative analysis of the spinal cord injuries by using diffusion patterns  

NASA Astrophysics Data System (ADS)

In medical imaging, magnetic resonance imaging sequences are able to provide information of the damaged brain structure and the neuronal connections. The sequences can be analyzed to form 3D models of the geometry and further including functional information of the neurons of the specific brain area to develop functional models. Modeling offers a tool which can be used for the modeling of brain trauma from images of the patients and thus information to tailor the properties of the transplanted cells. In this paper, we present image-based methods for the analysis of human spinal cord injuries. In this effort, we use three dimensional diffusion tensor imaging, which is an effective method for analyzing the response of the water molecules. This way, our idea is to study how the injury affects on the tissues and how this can be made visible in the imaging. In this paper, we present here a study of spinal cord analysis to two subjects, one healthy volunteer and one spinal cord injury patient. We have done segmentations and volumetric analysis for detection of anatomical differences. The functional differences are analyzed by using diffusion tensor imaging. The obtained results show that this kind of analysis is capable of finding differences in spinal cords anatomy and function.

Hannula, Markus; Olubamiji, Adeola; Kunttu, Iivari; Dastidar, Prasun; Soimakallio, Seppo; Öhman, Juha; Hyttinen, Jari

2011-03-01

306

A detailed phenotypic analysis of immune cell populations in the bronchoalveolar lavage fluid of atopic asthmatics after segmental allergen challenge  

PubMed Central

Background Atopic asthma is characterized by intermittent exacerbations triggered by exposure to allergen. Exacerbations are characterized by an acute inflammatory reaction in the airways, with recruitment of both innate and adaptive immune cells. These cell populations as well as soluble factors are critical for initiating and controlling the inflammatory processes in allergic asthma. Detailed data on the numbers and types of cells recruited following allergen challenge is lacking. In this paper we present an extensive phenotypic analysis of the inflammatory cell infiltrate present in the bronchoalveolar lavage (BAL) fluid following bronchoscopically directed allergen challenge in mild atopic asthmatics. Methods A re-analysis of pooled data obtained prior to intervention in our randomized, placebo controlled, double blinded study (costimulation inhibition in asthma trial [CIA]) was performed. Twenty-four subjects underwent bronchoscopically directed segmental allergen challenge followed by BAL collection 48 hours later. The BAL fluid was analyzed by multi-color flow cytometry for immune cell populations and multi-plex ELISA for cytokine detection. Results Allergen instillation induced pro-inflammatory cytokines (IL-6) and immune modulating cytokines (IL-2, IFN-?, and IL-10) along with an increase in lymphocytes and suppressor cells (Tregs and MDSC). Interestingly, membrane expression of CD30 was identified on lymphocytes, especially Tregs, but not eosinophils. Soluble CD30 was also detected in the BAL fluid after allergen challenge in adult atopic asthmatics. Conclusions After segmental allergen challenge of adult atopic asthmatics, cell types associated with a pro-inflammatory as well as an anti-inflammatory response are detected within the BAL fluid of the lung. PMID:24330650

2013-01-01

307

Comparative analysis of the distribution of segmented filamentous bacteria in humans, mice and chickens  

PubMed Central

Segmented filamentous bacteria (SFB) are indigenous gut commensal bacteria. They are commonly detected in the gastrointestinal tracts of both vertebrates and invertebrates. Despite the significant role they have in the modulation of the development of host immune systems, little information exists regarding the presence of SFB in humans. The aim of this study was to investigate the distribution and diversity of SFB in humans and to determine their phylogenetic relationships with their hosts. Gut contents from 251 humans, 92 mice and 72 chickens were collected for bacterial genomic DNA extraction and subjected to SFB 16S rRNA-specific PCR detection. The results showed SFB colonization to be age-dependent in humans, with the majority of individuals colonized within the first 2 years of life, but this colonization disappeared by the age of 3 years. Results of 16S rRNA sequencing showed that multiple operational taxonomic units of SFB could exist in the same individuals. Cross-species comparison among human, mouse and chicken samples demonstrated that each host possessed an exclusive predominant SFB sequence. In summary, our results showed that SFB display host specificity, and SFB colonization, which occurs early in human life, declines in an age-dependent manner. PMID:23151642

Yin, Yeshi; Wang, Yu; Zhu, Liying; Liu, Wei; Liao, Ningbo; Jiang, Mizu; Zhu, Baoli; Yu, Hongwei D; Xiang, Charlie; Wang, Xin

2013-01-01

308

Who Will More Likely Buy PHEV: A Detailed Market Segmentation Analysis  

SciTech Connect

Understanding the diverse PHEV purchase behaviors among prospective new car buyers is key for designing efficient and effective policies for promoting new energy vehicle technologies. The ORNL MA3T model developed for the U.S. Department of Energy is described and used to project PHEV purchase probabilities by different consumers. MA3T disaggregates the U.S. household vehicle market into 1458 consumer segments based on region, residential area, driver type, technology attitude, home charging availability and work charging availability and is calibrated to the EIA s Annual Energy Outlook. Simulation results from MA3T are used to identify the more likely PHEV buyers and provide explanations. It is observed that consumers who have home charging, drive more frequently and live in urban area are more likely to buy a PHEV. Early adopters are projected to be more likely PHEV buyers in the early market, but the PHEV purchase probability by the late majority consumer can increase over time when PHEV gradually becomes a familiar product. Copyright Form of EVS25.

Lin, Zhenhong [ORNL] [ORNL; Greene, David L [ORNL] [ORNL

2010-01-01

309

Molecular combing in the analysis of developmentally regulated amplified segments of Bradysia hygida.  

PubMed

Molecular combing technology is an important new tool for the functional and physical mapping of genome segments. It is designed to identify amplifications, microdeletions, and rearrangements in a DNA sequence and to study the process of DNA replication. This technique has recently been used to identify and analyze the dynamics of replication in amplified domains. In Bradysia hygida, multiple amplification initiation sites are predicted to exist upstream of the BhC4-1 gene. However, it has been impossible to identify them using the available standard techniques. The aim of this study was to optimize molecular combing technology to obtain DNA fibers from the polytene nuclei of the salivary glands of B. hygida to study the dynamics of DNA replication in this organism. Our results suggest that combing this DNA without prior purification of the polytene nuclei is possible. The density, integrity, and linearity of the DNA fibers were analyzed, fibers 50 to 300 kb in length were detected, and a 9-kb fragment within the amplified region was visualized using biotin detected by Alexa Fluor 488-conjugated streptavidin technique. The feasibility of physically mapping these fibers demonstrated in this study suggests that molecular combing may be used to identify the replication origin of the BhC4-1 amplicon. PMID:22911590

Passos, K J R; Togoro, S Y; Carignon, S; Koundrioukoff, S; Lachages, A-M; Debatisse, M; Fernandez, M A

2012-01-01

310

ANALYSIS OF THE MAPS OF REGIONS OF THE EUROPEAN UNION PUBLISHED IN THE VOLUME \\  

Microsoft Academic Search

A detailed analysis from cartographic point of view has been performed of 51 color maps of regions in the 25 Member States of the European Union and the 2 candidate countries, published in the special volume of Eurostat \\

VENETA KOTSEVA

311

Site-SpecificAnalysis&Management Agronomy Journal Volume 100, Issue 5 2008 1463  

E-print Network

Site-SpecificAnalysis&Management Agronomy Journal · Volume 100, Issue 5 · 2008 1463 Published of Agronomy, 677 South Segoe Road, Madison, WI 53711. All rights reserved. No part of this periodical may

312

Computer Assisted Data Analysis in the Dye Dilution Technique for Plasma Volume Measurement.  

ERIC Educational Resources Information Center

Describes a method for undergraduate physiology students to measure plasma volume by the dye dilution technique, in which a computer is used to interpret data. Includes the computer program for the data analysis. (CS)

Bishop, Marvin; Robinson, Gerald D.

1981-01-01

313

A detailed analysis of 16S ribosomal RNA gene segments for the diagnosis of pathogenic bacteria.  

PubMed Central

Bacterial 16S ribosomal RNA (rRNA) genes contain nine “hypervariable regions” (V1 – V9) that demonstrate considerable sequence diversity among different bacteria. Species-specific sequences within a given hypervariable region constitute useful targets for diagnostic assays and other scientific investigations. No single region can differentiate among all bacteria; therefore, systematic studies that compare the relative advantage of each region for specific diagnostic goals are needed. We characterized V1 - V8 in 110 different bacterial species including common blood borne pathogens, CDC-defined select agents and environmental microflora. Sequence similarity dendrograms were created for hypervariable regions V1 – V8, and for selected combinations of regions or short segments within individual hypervariable regions that might be appropriate for DNA probing and real-time PCR. We determined that V1 best differentiated among Staphylococcus aureus and coagulase negative Staphylococcus sp. V2 and V3 were most suitable for distinguishing all bacterial species to the genus level except for closely related enterobacteriaceae. V2 best distinguished among Mycobacterial species and V3 among Haemophilus species. The 58 nucleotides-long V6 could distinguish among most bacterial species except enterobacteriaceae. V6 was also noteworthy for being able to differentiate among all CDC-defined select agents including Bacillus anthracis, which differed from B. cereus by a single polymorphism. V4, V5, V7 and V8 were less useful targets for genus or species-specific probes. The hypervariable sequence-specific dendrograms and the “MEGALIGN” files provided online will be highly useful tools for designing specific probes and primers for molecular assays to detect pathogenic bacteria, including select agents. PMID:17391789

Chakravorty, Soumitesh; Helb, Danica; Burday, Michele; Connell, Nancy; Alland, David

2007-01-01

314

Oesophageal motility, luminal pH, and electrocardiographic-ST segment analysis during spontaneous episodes of angina like chest pain.  

PubMed Central

The relation between oesophageal motility, luminal pH, and spontaneous pain events in 47 patients with recurrent angina like pain and normal coronary arteries was investigated. Preliminary investigation by conventional station pull through manometry (SPTM), was followed by a 24 hour period of ambulatory oesophageal motility and luminal pH monitoring. Computerised analysis of motility and pH data recorded during chest pain was then compared with pre-elected control samples taken before and after symptoms. Concurrent real time electrocardiographic (ECG)-ST segment analysis was performed to catalogue any ECG-STT wave changes indicative of myocardial ischaemia. SPTM showed a high group percentage incidence of simultaneous contractions (mean (SD) 11.1 (2.3)%) and a raised lower oesophageal sphincter tone (57.4 (15.2) mm Hg). During ambulatory monitoring, 35 patients experienced one or more episode of angina, providing a total of 59 pain events, although no significant change in group motility and reflux parameters peculiar to episodes of chest pain were found. Ischaemic ECG changes were detected in 10 (21%) patients, but were accompanied by pain in only two. Independent analysis of the ECG traces corresponding to these purported ischaemic ECG events determined them unequivocal in three patients and probable in a further two. No apparent correlation was noted, however, between these ECG events and corresponding patterns of motility or reflux. PMID:1740283

Hick, D G; Morrison, J F; Casey, J F; al-Ashhab, W; Williams, G J; Davies, G A

1992-01-01

315

Automated segmentation of the lungs from high resolution CT images for quantitative study of chronic obstructive pulmonary diseases  

NASA Astrophysics Data System (ADS)

Chronic obstructive pulmonary diseases (COPD) are debilitating conditions of the lung and are the fourth leading cause of death in the United States. Early diagnosis is critical for timely intervention and effective treatment. The ability to quantify particular imaging features of specific pathology and accurately assess progression or response to treatment with current imaging tools is relatively poor. The goal of this project was to develop automated segmentation techniques that would be clinically useful as computer assisted diagnostic tools for COPD. The lungs were segmented using an optimized segmentation threshold and the trachea was segmented using a fixed threshold characteristic of air. The segmented images were smoothed by a morphological close operation using spherical elements of different sizes. The results were compared to other segmentation approaches using an optimized threshold to segment the trachea. Comparison of the segmentation results from 10 datasets showed that the method of trachea segmentation using a fixed air threshold followed by morphological closing with spherical element of size 23x23x5 yielded the best results. Inclusion of greater number of pulmonary vessels in the lung volume is important for the development of computer assisted diagnostic tools because the physiological changes of COPD can result in quantifiable anatomic changes in pulmonary vessels. Using a fixed threshold to segment the trachea removed airways from the lungs to a better extent as compared to using an optimized threshold. Preliminary measurements gathered from patient"s CT scans suggest that segmented images can be used for accurate analysis of total lung volume and volumes of regional lung parenchyma. Additionally, reproducible segmentation allows for quantification of specific pathologic features, such as lower intensity pixels, which are characteristic of abnormal air spaces in diseases like emphysema.

Garg, Ishita; Karwoski, Ronald A.; Camp, Jon J.; Bartholmai, Brian J.; Robb, Richard A.

2005-04-01

316

Three stage level set segmentation of mass core, periphery, and spiculations for automated image analysis of digital mammograms  

NASA Astrophysics Data System (ADS)

In this dissertation, level set methods are employed to segment masses in digital mammographic images and to classify land cover classes in hyperspectral data. For the mammography computer aided diagnosis (CAD) application, level set-based segmentation methods are designed and validated for mass-periphery segmentation, spiculation segmentation, and core segmentation. The proposed periphery segmentation uses the narrowband level set method in conjunction with an adaptive speed function based on a measure of the boundary complexity in the polar domain. The boundary complexity term is shown to be beneficial for delineating challenging masses with ill-defined and irregularly shaped borders. The proposed method is shown to outperform periphery segmentation methods currently reported in the literature. The proposed mass spiculation segmentation uses a generalized form of the Dixon and Taylor Line Operator along with narrowband level sets using a customized speed function. The resulting spiculation features are shown to be very beneficial for classifying the mass as benign or malignant. For example, when using patient age and texture features combined with a maximum likelihood (ML) classifier, the spiculation segmentation method increases the overall accuracy to 92% with 2 false negatives as compared to 87% with 4 false negatives when using periphery segmentation approaches. The proposed mass core segmentation uses the Chan-Vese level set method with a minimal variance criterion. The resulting core features are shown to be effective and comparable to periphery features, and are shown to reduce the number of false negatives in some cases. Most mammographic CAD systems use only a periphery segmentation, so those systems could potentially benefit from core features.

Ball, John Eugene

317

Segmental hair analysis for differentiation of tilidine intake from external contamination using LC-ESI-MS/MS and MALDI-MS/MS imaging.  

PubMed

Segmental hair analysis has been used for monitoring changes of consumption habit of drugs. Contamination from the environment or sweat might cause interpretative problems. For this reason, hair analysis results were compared in hair samples taken 24?h and 30?days after a single tilidine dose. The 24-h hair samples already showed high concentrations of tilidine and nortilidine. Analysis of wash water from sample preparation confirmed external contamination by sweat as reason. The 30-day hair samples were still positive for tilidine in all segments. Negative wash-water analysis proved incorporation from sweat into the hair matrix. Interpretation of a forensic case was requested where two children had been administered tilidine by their nanny and tilidine/nortilidine had been detected in all hair segments, possibly indicating multiple applications. Taking into consideration the results of the present study and of MALDI-MS imaging, a single application as cause for analytical results could no longer be excluded. Interpretation of consumption behaviour of tilidine based on segmental hair analysis has to be done with caution, even after typical wash procedures during sample preparation. External sweat contamination followed by incorporation into the hair matrix can mimic chronic intake. For assessment of external contamination, hair samples should not only be collected several weeks but also one to a few days after intake. MALDI-MS imaging of single hair can be a complementary tool for interpretation. Limitations for interpretation of segmental hair analysis shown here might also be applicable to drugs with comparable physicochemical and pharmacokinetic properties. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24935086

Poetzsch, Michael; Baumgartner, Markus R; Steuer, Andrea E; Kraemer, Thomas

2015-02-01

318

Validity of segmental multiple-frequency bioelectrical impedance analysis to estimate body composition of adults across a range of body mass indexes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Objective: Compare estimates of body composition using segmental, multiple frequency bioelectrical impedance analysis (MF-BIA) with dual x-ray absorptiometry (DXA) in healthy adults across a range of body mass index (BMI). Methods: Percent body fat (%BF), fat-mass (FM), and fat-free mass (FFM) asses...

319

Managing the long-term profit yield from market segments in a hotel environment: a case study on the implementation of customer profitability analysis  

Microsoft Academic Search

Customer profitability analysis (CPA) is a technique which assesses the profit yield from market segments, primarily to provide management with information that will enhance long-term yield decisions. This paper documents the findings of a study which was carried out in order to test the feasibility of implementing a customer profitability system in a hotel environment. The test site chosen for

Breffni Noone; Peter Griffin

1999-01-01

320

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 4: Mission peculiar spacecraft segment and module specifications  

NASA Technical Reports Server (NTRS)

The specifications for the Earth Observatory Satellite (EOS) peculiar spacecraft segment and associated subsystems and modules are presented. The specifications considered include the following: (1) wideband communications subsystem module, (2) mission peculiar software, (3) hydrazine propulsion subsystem module, (4) solar array assembly, and (5) the scanning spectral radiometer.

1974-01-01

321

Coupled-wave analysis of apodized volume gratings  

E-print Network

, "Description and use of LSODE, the Livermore Solver for Ordinary Differential Equations", NASA reference a method for creating apodization in volume holograms with approximately Gaussian spatial refractive index interconnects", Photonics Switching and Inter- connects, A. Marrakchi (ed.), Marcel Dekker, New York, 249

Glebov, Leon

322

Partial volume correction using an energy multiresolution analysis  

Microsoft Academic Search

Position Emission Tomography (PET) allows the in-vivo monitoring of functional processes in the body. However its limited spatial resolution induces Partial Volume Effect (PVE), which leads to a loss of signal in tissues of size similar to the Point Spread Function (PSF) of the imaging device and induces activity spillover between adjacent structures with different amounts of activity. The aim

Francisca P. Figueiras; Xavier Jimenez; Deborah Pareto; Juan D. Gispert

2009-01-01

323

Subcortical brain segmentation of two dimensional T1-weighted data sets with FMRIB's Integrated Registration and Segmentation Tool (FIRST)  

PubMed Central

Brain atrophy has been identified as an important contributing factor to the development of disability in multiple sclerosis (MS). In this respect, more and more interest is focussing on the role of deep grey matter (DGM) areas. Novel data analysis pipelines are available for the automatic segmentation of DGM using three-dimensional (3D) MRI data. However, in clinical trials, often no such high-resolution data are acquired and hence no conclusions regarding the impact of new treatments on DGM atrophy were possible so far. In this work, we used FMRIB's Integrated Registration and Segmentation Tool (FIRST) to evaluate the possibility of segmenting DGM structures using standard two-dimensional (2D) T1-weighted MRI. In a cohort of 70 MS patients, both 2D and 3D T1-weighted data were acquired. The thalamus, putamen, pallidum, nucleus accumbens, and caudate nucleus were bilaterally segmented using FIRST. Volumes were calculated for each structure and for the sum of basal ganglia (BG) as well as for the total DGM. The accuracy and reliability of the 2D data segmentation were compared with the respective results of 3D segmentations using volume difference, volume overlap and intra-class correlation coefficients (ICCs). The mean differences for the individual substructures were between 1.3% (putamen) and ?25.2% (nucleus accumbens). The respective values for the BG were ?2.7% and for DGM 1.3%. Mean volume overlap was between 89.1% (thalamus) and 61.5% (nucleus accumbens); BG: 84.1%; DGM: 86.3%. Regarding ICC, all structures showed good agreement with the exception of the nucleus accumbens. The results of the segmentation were additionally validated through expert manual delineation of the caudate nucleus and putamen in a subset of the 3D data. In conclusion, we demonstrate that subcortical segmentation of 2D data are feasible using FIRST. The larger subcortical GM structures can be segmented with high consistency. This forms the basis for the application of FIRST in large 2D MRI data sets of clinical trials in order to determine the impact of therapeutic interventions on DGM atrophy in MS. PMID:25610766

Amann, Michael; And?lová, Michaela; Pfister, Armanda; Mueller-Lenke, Nicole; Traud, Stefan; Reinhardt, Julia; Magon, Stefano; Bendfeldt, Kerstin; Kappos, Ludwig; Radue, Ernst-Wilhelm; Stippich, Christoph; Sprenger, Till

2014-01-01

324

Bayesian blocks in two or more dimensions: Image segmentation and cluster analysis  

NASA Astrophysics Data System (ADS)

I describe an extension, to higher dimensions, of the Bayesian Blocks algorithm for estimating signals in noisy time series data [17,18]. We seek the partition of the data space with the maximum posterior for a model consisting of a homogeneous Poisson process in each partition element. Model Mn, attributing the data within region n of the data space to a Poisson process with a fixed event rate ?n, has a global posterior depending on only N, the number of data points in the region, and V, its volume: P(Mn)=?(N,V)=?(N+1)?(V-N+1)/?(V+2)=N!(V-N)!/(V+1)!. (1) Note that ?n does not appear, since it has been marginalized, using a flat, improper prior. Other priors yield similar formulas. This expression is valid for a data space of any dimension. Suppose two regions, described by N1, V1 and N2, V2, are candidates for being merged into one. The Bayes merge factor, giving the posterior ratio for merged and not merged, respectively, is: P=?(N1+N2,V1+V2)/?(N1,V1)?(N2,V2). (2) Then collect data points into blocks with this cell coalescence algorithm: (1) Identify each cell of the Voronoi tessellation of the data as a block (2) Iteratively merge the pair of blocks with the largest merge factor (3) Halt when the maximum merge factor falls below 1 In many applications it convenient to restrict mergers to neighboring blocks. This algorithm partitions the space into a set of relatively few blocks, each having a density equal to the number of its data points divided by its volume. Adjacent high-density blocks can be collected into clusters. This method allows detection of clusters in high-dimensional data spaces, with the following properties: • The number of clusters is determined, not assumed • Clusters can have any shape: - Avoid the conventional Gaussian assumption - Shapes can include both concavities and convexities - Blocks and clusters do not even have to be simply connected • Cluster density profiles are estimated, not just the boundaries • Any slowly varying background is automatically identified • No binning of the raw data is necessary

Scargle, Jeffrey D.

2002-05-01

325

Adjunctive Manual Thrombus Aspiration during ST-Segment Elevation Myocardial Infarction: A Meta-Analysis of Randomized Controlled Trials  

PubMed Central

Objective The aim of this study was to synthesize evidence by examining the effects of manual thrombus aspiration on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Methods and Results A total of 26 randomized controlled trials (RCTs), enrolling 11,780 patients, with 5,869 patients randomized to manual thrombus aspiration and 5,911 patients randomized to conventional percutaneous coronary intervention (PCI), were included in the meta-analysis. Separate clinical outcome analyses were based on different follow-up periods. There were no statistically reductions in the incidences of mortality (risk ratio [RR], 0.86 [95% confidence interval [CI]: 0.73 to 1.02]), reinfarction (RR, 0.62 [CI, 0.31 to 1.32]) or target vessel revascularization (RR, 0.89 [CI, 0.75 to 1.05]) in the manual thrombus aspiration arm at 12 to 24 months of follow-up. The composite major adverse cardiac events (MACEs) outcomes were significantly lower in the manual thrombus aspiration arm over the long-term follow-up (RR, 0.76 [CI, 0.63 to 0.91]). A lower incidence of reinfarction was observed in the hospital to 30 days (RR, 0.59 [CI, 0.37 to 0.92]). Conclusion The present meta-analysis suggested that there was no evidence that using manual thrombus aspiration in patients with STEMI could provide distinct benefits in long-term clinical outcomes. PMID:25405874

Deng, Song-Bai; Wang, Jing; Xiao, Jun; Wu, Ling; Jing, Xiao-Dong; Yan, Yu-Ling; Du, Jian-Lin; Liu, Ya-Jie; She, Qiang

2014-01-01

326

The ACODEA Framework: Developing Segmentation and Classification Schemes for Fully Automatic Analysis of Online Discussions  

ERIC Educational Resources Information Center

Research related to online discussions frequently faces the problem of analyzing huge corpora. Natural Language Processing (NLP) technologies may allow automating this analysis. However, the state-of-the-art in machine learning and text mining approaches yields models that do not transfer well between corpora related to different topics. Also,…

Mu, Jin; Stegmann, Karsten; Mayfield, Elijah; Rose, Carolyn; Fischer, Frank

2012-01-01

327

Interactive Exploration and Analysis of Large-Scale Simulations Using Topology-Based Data Segmentation  

Microsoft Academic Search

Large-scale simulations are increasingly being used to study complex scientific and engineering phenomena. As a result, advanced visualization and data analysis are also becoming an integral part of the scientific process. Often, a key step in extracting insight from these large simulations involves the definition, extraction, and evaluation of features in the space and time coordinates of the solution. However,

Peer-Timo Bremer; Gunther H. Weber; Julien Tierny; Valerio Pascucci; Marcus S. Day; John B. Bell

2011-01-01

328

Conformational analysis of peptide analogues of silkmoth chorion protein segments using CD, NMR and molecular modelling  

Microsoft Academic Search

Silkmoth proteins secreted from the follicular cells that surround the oocyte form a large extracellular assembly which is important for protecting and sustaining the structure of the oocyte and the developing embryo. These proteins have been classified into two major families (A and B). Sequence analysis showed conservation of a central domain containing long stretches of six amino acid residue

Dimitra C. Benaki; Emmanuel Mikros; Stavros J. Hamodrakas

2004-01-01

329

Appendicular skeletal muscle mass: prediction from multiple frequency segmental bioimpedance analysis  

Microsoft Academic Search

Objectives: Bioimpedance analysis (BIA) methods have potential to predict appendicular skeletal muscle mass (SM), although available 50 kHz prediction models include, in addition to impedance (Z), an independent age term. An age term in models is undesirable as it reflects incomplete understanding of underlying conduction physiology. This study tested the hypothesis, based on fluid distribution models related to aging, that

A Pietrobelli; P Morini; N Battistini; G Chiumello; C Nuñez; SB Heymsfield

1998-01-01

330

Potential market segments for genetically modified food: Results from cluster analysis  

Microsoft Academic Search

The commercial success of genetically modified (GM) food may be improved with appropriately targeted marketing. To that end, data from a survey of supermarket shoppers in New Zealand were analysed with a cluster analysis. A six-cluster solution found three clusters with positive intentions to purchase GM apples and three clusters with negative intentions. Positive intentions appeared to result from either

William Kaye-Blake; Anna OConnell; Charles Lamb

2007-01-01

331

An analysis of light-induced admittance changes in rod outer segments  

PubMed Central

1. Measurements were made of the time course and amplitude of the change in real part of admittance, ?G, of a suspension of frog rod outer segments, following a flash of light bleaching about 1% of the rhodopsin content of the rods. The measurements, based on the use of a specially designed marginal oscillator, covered the frequency range between 500 Hz and 17 MHz. 2. The components of response, previously described for rods prepared by a method involving exposure to strongly hypertonic sucrose solutions, are present in similar form when rods are isolated and maintained in isotonic solutions made up with equi-osmotic concentrations of NaCl and sucrose or with Na2SO4. 3. Component I, identified as a slowly developing positive ?G apparent at very low frequencies, is frequency-independent up to the characteristic frequency of admittance for the suspension, fY (about 2 MHz for rods suspended in a solution having the conductivity of Ringer solution), but decreases at still higher frequencies. 4. Component II, identified as a rapidly developing positive ?G which appears only above a critical frequency about 2·5 decades below fY, increases approximately logarithmically with frequency to reach a limiting amplitude in the region of fY. 5. The amplitude of component II, ?GII, measured in the region of fY, varies linearly with the conductivity of the suspending medium, Go, under conditions in which the conductivity of the rod interior is also a linear function of the external conductivity. The relation for a flash bleaching 1% of the rhodopsin content of the dark-adapted rod is [Formula: see text] 6. Measurements made on rods suspended in a low-conductivity solution, which has the effect of reducing the conductivity of the rod interior to about one ninth its value for rods suspended in Ringer solution, reveal a decline in component II for frequencies above 8 MHz. 7. To explain the frequency dependence of component II and its dependence on conductivity, it is proposed that component II arises from a light-induced increase in conductance of the disk membranes which obstruct the longitudinal flow of current through the rod interior except at very high frequencies. 8. The disk-membrane conductance increase for rods suspended in a solution having the conductivity of Ringer solution is calculated to be 4·3 × 10-11 mho/rhodpsin molecule bleached, a value which is similar to what has been found for ionic channels operated by membrane potential change in the nerve membrane and by synaptic transmitter in the postjunctional membrane. 9. No component of response has been observed which could be reliably attributed to a surface membrane conductance decrease of the type observed in receptor cells in the retina. PMID:4540195

Falk, G.; Fatt, P.

1973-01-01

332

Volumetric brain analysis in neurosurgery: Part 2. Brain and CSF volumes discriminate neurocognitive outcomes in hydrocephalus.  

PubMed

OBJECT The evaluation of hydrocephalus remains focused on ventricular size, yet the goal of treatment is to allow for healthy brain development. It is likely that brain volume is more related to cognitive development than is fluid volume in children with hydrocephalus. This study tests this hypothesis by comparing brain and fluid volumes with neurocognitive outcome in pediatric patients with hydrocephalus. METHODS Warf and colleagues previously acquired CT scans for pediatric patients in Uganda with myelomeningocele, measured frontal-occipital horn ratio (FOHR), and administered the modified Bayley Scales of Infant Development, third edition (BSID-III) to measure neurocognitive outcome that did not correlate with FOHR. In this present study, brain and fluid volumes were measured in 33 of these patients, 26 of whom required surgical treatment for hydrocephalus. Linear discrimination analysis (LDA) was used to test whether age-normalized brain and fluid volumes can discriminate neurocognitive outcome. RESULTS Hydrocephalic patients show normal to small brain volumes and substantially larger fluid volumes compared with normal values. FOHR correlates highly with fluid volume (r = 0.84, p < 0.001) and substantially less with brain volume (r = -0.37, p = 0.03), while brain and fluid volumes do not correlate with each other (p = 0.99). Brain and CSF volumes correlated best with fine motor (p = 0.03, p = 0.01), cognitive (p = 0.05, p = 0.09), and expressive communication (p = 0.08, p = 0.08) scores. A combination of these 3 scores was used as a multivariate measure of neurocognitive outcome. Brain volume alone, unlike fluid volume, could discriminate high from low cognitive outcome (by t-test and ANOVA). It was shown that a combination of age-normalized brain and fluid volumes can discriminate neurocognitive outcome by 2-way LDA (p < 0.01) and 3-way LDA (p < 0.01). The multivariate LDA demonstrated the contribution of large fluid volume to a decrement in cognition. CONCLUSIONS Hydrocephalus is treated by normalizing CSF, but normal brain development depends on brain growth. A combination of brain and CSF volumes appears to be significantly more powerful at predicting good versus poor neurocognitive outcomes in patients with hydrocephalus than either volume alone. PMID:25431901

Mandell, Jason G; Kulkarni, Abhaya V; Warf, Benjamin C; Schiff, Steven J

2014-11-28

333

Dynamic analysis of the activley controlled segmented mirror of the W. M. Keck ten-meter telescope  

Microsoft Academic Search

The W. M. Keck Observatory and Telescope are presently under construction on Mauna Kea, Hawaii. When completed in 1990, the telescope will be the world's largest instrument for astronomical observations at visible and infrared wavelengths. The primary mirror has a diameter of 10 m and consists of a mosaic of 36 hexagonal segments, with the orientation of each segment actively

Jean-Noel Aubrun; Kenneth R. Lorell; Terry S. Mast; J. Nelson

1987-01-01

334

Industrial process heat data analysis and evaluation. Volume 2  

SciTech Connect

The Solar Energy Research Institute (SERI) has modeled seven of the Department of Energy (DOE) sponsored solar Industrial Process Heat (IPH) field experiments and has generated thermal performance predictions for each project. Additionally, these performance predictions have been compared with actual performance measurements taken at the projects. Predictions were generated using SOLIPH, an hour-by-hour computer code with the capability for modeling many types of solar IPH components and system configurations. Comparisons of reported and predicted performance resulted in good agreement when the field test reliability and availability was high. Volume I contains the main body of the work; objective model description, site configurations, model results, data comparisons, and summary. Volume II contains complete performance prediction results (tabular and graphic output) and computer program listings.

Lewandowski, A; Gee, R; May, K

1984-07-01

335

Industrial process heat data analysis and evaluation. Volume 1  

SciTech Connect

The Solar Energy Research Institute (SERI) has modeled seven of the Department of Energy (DOE) sponsored solar Industrial Process Heat (IPH) field experiments and has generated thermal performance predictions for each project. Additionally, these performance predictions have been compared with actual performance measurements taken at the projects. Predictions were generated using SOLIPH, an hour-by-hour computer code with the capability for modeling many types of solar IPH components and system configurations. Comparisons of reported and predicted performance resulted in good agreement when the field test reliability and availability was high. Volume I contains the main body of the work: objective, model description, site configurations, model results, data comparisons, and summary. Volume II contains complete performance prediction results (tabular and graphic output) and computer program listings.

Lewandowski, A; Gee, R; May, K

1984-07-01

336

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 3: General purpose spacecraft segment and module specifications  

NASA Technical Reports Server (NTRS)

The specifications for the Earth Observatory Satellite (EOS) general purpose aircraft segment are presented. The satellite is designed to provide attitude stabilization, electrical power, and a communications data handling subsystem which can support various mission peculiar subsystems. The various specifications considered include the following: (1) structures subsystem, (2) thermal control subsystem, (3) communications and data handling subsystem module, (4) attitude control subsystem module, (5) power subsystem module, and (6) electrical integration subsystem.

1974-01-01

337

Logitboost weka classifier speech segmentation  

Microsoft Academic Search

Segmenting the speech signals on the basis of time-frequency analysis is the most natural approach. Boundaries are located in places where energy of some frequency subband rapidly changes. Speech segmentation method which bases on dis- crete wavelet transform, the resulting power spectrum and its derivatives is presented. This information allows to locate the boundaries of phonemes. A statistical classification method

Bartosz Ziólko; Suresh Manandhar; Richard C. Wilson; Mariusz Ziólko

2008-01-01

338

Complete Genomic Sequence and Comparative Analysis of the Genome Segments of Sweet Potato Chlorotic Stunt Virus in China  

PubMed Central

Background Sweet potato chlorotic stunt virus (family Closteroviridae, genus Crinivirus) features a large bipartite, single-stranded, positive-sense RNA genome. To date, only three complete genomic sequences of SPCSV can be accessed through GenBank. SPCSV was first detected from China in 2011, only partial genomic sequences have been determined in the country. No report on the complete genomic sequence and genome structure of Chinese SPCSV isolates or the genetic relation between isolates from China and other countries is available. Methodology/Principal Findings The complete genomic sequences of five isolates from different areas in China were characterized. This study is the first to report the complete genome sequences of SPCSV from whitefly vectors. Genome structure analysis showed that isolates of WA and EA strains from China have the same coding protein as isolates Can181-9 and m2-47, respectively. Twenty cp genes and four RNA1 partial segments were sequenced and analyzed, and the nucleotide identities of complete genomic, cp, and RNA1 partial sequences were determined. Results indicated high conservation among strains and significant differences between WA and EA strains. Genetic analysis demonstrated that, except for isolates from Guangdong Province, SPCSVs from other areas belong to the WA strain. Genome organization analysis showed that the isolates in this study lack the p22 gene. Conclusions/Significance We presented the complete genome sequences of SPCSV in China. Comparison of nucleotide identities and genome structures between these isolates and previously reported isolates showed slight differences. The nucleotide identities of different SPCSV isolates showed high conservation among strains and significant differences between strains. All nine isolates in this study lacked p22 gene. WA strains were more extensively distributed than EA strains in China. These data provide important insights into the molecular variation and genomic structure of SPCSV in China as well as genetic relationships among isolates from China and other countries. PMID:25170926

Qin, Yanhong; Wang, Li; Zhang, Zhenchen; Qiao, Qi; Zhang, Desheng; Tian, Yuting; Wang, Shuang; Wang, Yongjiang; Yan, Zhaoling

2014-01-01

339

Conferences on Orthodontics Advances in Science and Technology, Monterey, September 2002 (in 3D Visualization of the Craniofacial Patient: Volume Segmentation, Data  

E-print Network

, memon, jamesmah} @usc.edu Keywords: 3D Visualization, volume rendering, CT, dentition models, jaw in this area, with a previous method described using spherical markers placed on the skeleton and dentition

Shahabi, Cyrus

340

Underground Test Area Subproject Phase I Data Analysis Task. Volume II - Potentiometric Data Document Package  

SciTech Connect

Volume II of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the potentiometric data. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

None

1996-12-01

341

Underground Test Area Subproject Phase I Data Analysis Task. Volume VI - Groundwater Flow Model Documentation Package  

SciTech Connect

Volume VI of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the groundwater flow model data. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

None

1996-11-01

342

Underground Test Area Subproject Phase I Data Analysis Task. Volume VII - Tritium Transport Model Documentation Package  

SciTech Connect

Volume VII of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the tritium transport model documentation. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

None

1996-12-01

343

62 LINCOLN LABORATORY JOURNAL VOLUME 20, NUMBER 1, 2013 SOCIAL NETWORK ANALYSIS WITH CONTENT AND GRAPHS  

E-print Network

in social network analysis. The quantity of content-based data created every day by traditional and social inferences from social networks. Network construction from general, real-world data presents several62 LINCOLN LABORATORY JOURNAL VOLUME 20, NUMBER 1, 2013 SOCIAL NETWORK ANALYSIS WITH CONTENT

344

Synfuel program analysis. Volume 2: VENVAL users manual  

NASA Astrophysics Data System (ADS)

This volume is intended for program analysts and is a users manual for the VENVAL model. It contains specific explanations as to input data requirements and programming procedures for the use of this model. VENVAL is a generalized computer program to aid in evaluation of prospective private sector production ventures. The program can project interrelated values of installed capacity, production, sales revenue, operating costs, depreciation, investment, dent, earnings, taxes, return on investment, depletion, and cash flow measures. It can also compute related public sector and other external costs and revenues if unit costs are furnished.

Muddiman, J. B.; Whelan, J. W.

1980-07-01

345

Multifractal and singularity analysis of highway volume data  

NASA Astrophysics Data System (ADS)

Recent work has shown that the mathematics of multifractal can be used to provide a quantitative signature in many fields. In this paper, we investigate the traffic time series for volume data observed on Guangshen highway. Firstly, we find there exists a multifractal behavior in the traffic data, and the data on both work days and rest days have similar multifractality. Then, we study the singularity of these data. A singularity exponent method based on multifractal theory is proposed to extract or classify singular data, which is more precise and clear than the Hölder exponent method.

Dai, Meifeng; Zhang, Cheng; Zhang, Danping

2014-08-01

346

An analysis of malar fat volume in two age groups: implications for craniofacial surgery.  

PubMed

Objective?To evaluate how malar fat pad (MFP) volumes vary with age, after controlling for gender and body mass index (BMI). Study Design?A prospective case-control study evaluating volume of the MFP in women of two age groups. Methods?Soft tissue dimensions were measured in eight subjects using magnetic resonance imaging. A multiplanar localizing sequence, followed in sagittal and coronal orientations using a turbo spin echo sequence, was performed to define the MFP. Volumetric calculations were then performed using a 3D image analysis application (Dextroscope, Volume Interactions, Republic of Singapore) to circumscribe areas, orient dimensions, and calculate volumes of the MFP. Results?These data reveal no significant difference in the mean (standard deviation) right MFP (p?=?0.50), left MFP (p?=?0.41), or total MFP (p?=?0.45) volumes when comparing the two age groups. In addition, these data indicate that there was no correlation between age and total MFP volume (Pearson correlation coefficient 0.27). Moreover, there was no correlation between age and the ratio of total volume/BMI (Pearson correlation coefficient -0.18). Conclusions?Although the sample size of this study was small, these data indicate that ptosis of midfacial fat is more important than volume loss in midfacial aging. These data would suggest repositioning as the primary modality for craniofacial reconstruction. PMID:24294406

Corey, Christina L; Popelka, Gerald R; Barrera, Jose E; Most, Sam P

2012-12-01

347

Differential expression analysis of miRNA in peripheral blood mononuclear cells of patients with non-segmental vitiligo.  

PubMed

Vitiligo is a common depigmentary skin disease that may follow a pattern of multifactorial inheritance. The essential factors of its immunopathogenesis is thought to be the selective destruction of melanocytes. As a new class of microregulators of gene expression, miRNA have been reported to play vital roles in autoimmune diseases, metabolic diseases and cancer. This study sought to characterize the different miRNA expression pattern in the peripheral blood mononuclear cells (PBMC) of patients with non-segmental vitiligo (NSV) and healthy individuals and to examine their direct responses to thymosin ?1 (T?1) treatment. The miRNA expression profile in the PBMC of patients with NSV was analyzed using Exiqon's miRCURY LNA microRNA Array. The differentially expressed miRNA were validated by real-time quantitative polymerase chain reaction. We found that the expression levels of miR-224-3p and miR-4712-3p were upregulated, and miR-3940-5p was downregulated in the PBMC. The common clinical immune modulator T?1 changed the miRNA expression profile. Our analysis showed that differentially expressed miRNA were associated with the mechanism of immune imbalance of vitiligo and that T?1 could play an important role in changing the expression of these miRNA in the PBMC of patients with NSV. This study provided further evidence that miRNA may serve as novel drug targets for vitiligo therapeutic evaluation. PMID:25495156

Wang, Yi; Wang, Keyu; Liang, Jianhua; Yang, Hong; Dang, Ningning; Yang, Xi; Kong, Yi

2015-02-01

348

Theoretical analysis of curved Bragg diffraction images from plane wave reference volume holograms.  

PubMed

We analyze the shape of Bragg diffraction images from plane wave reference volume holograms in a 4-f geometry. When the volume hologram is probed by out-of-plane probe beams, the diffraction images become curved lines. Exploiting the k-sphere formulation and Fourier optics analysis, we present both geometrical and analytical solutions of the curved shape, which are distorted ellipses. Parameters and conditions related to the curvature are characterized, and experimental evidence is presented. PMID:19881666

Oh, Se Baek; Watson, Jonathan M; Barbastathis, George

2009-11-01

349

Driving Change in Community Colleges. Volume 1: Building Systems for Advancement to Self-Sufficiency; Volume 2: An Analysis of Change in Two Community Colleges.  

ERIC Educational Resources Information Center

This report contains two volumes: "Building Systems for Advancement to Self-Sufficiency," and "An Analysis of Change in Two Community Colleges." Volume 1 addresses the following topics: (1) the need and opportunity for change; (2) from promising practices toward systems for advancement; (3) institutional change strategies; (4) levers for…

Liebowitz, Marty; Haynes, Leslie; Milley, Jane

350

Improved inference in Bayesian segmentation using Monte Carlo sampling: application to hippocampal subfield volumetry.  

PubMed

Many segmentation algorithms in medical image analysis use Bayesian modeling to augment local image appearance with prior anatomical knowledge. Such methods often contain a large number of free parameters that are first estimated and then kept fixed during the actual segmentation process. However, a faithful Bayesian analysis would marginalize over such parameters, accounting for their uncertainty by considering all possible values they may take. Here we propose to incorporate this uncertainty into Bayesian segmentation methods in order to improve the inference process. In particular, we approximate the required marginalization over model parameters using computationally efficient Markov chain Monte Carlo techniques. We illustrate the proposed approach using a recently developed Bayesian method for the segmentation of hippocampal subfields in brain MRI scans, showing a significant improvement in an Alzheimer's disease classification task. As an additional benefit, the technique also allows one to compute informative "error bars" on the volume estimates of individual structures. PMID:23773521

Iglesias, Juan Eugenio; Sabuncu, Mert Rory; Van Leemput, Koen

2013-10-01

351

Registration-based segmentation of murine 4D cardiac micro-CT data using symmetric normalization  

PubMed Central

Micro-CT can play an important role in preclinical studies of cardiovascular disease because of its high spatial and temporal resolution. Quantitative analysis of 4D cardiac images requires segmentation of the cardiac chambers at each time point, an extremely time consuming process if done manually. To improve throughput this study proposes a pipeline for registration-based segmentation and functional analysis of 4D cardiac micro-CT data in the mouse. Following optimization and validation using simulations, the pipeline was applied to in vivo cardiac micro-CT data corresponding to 10 cardiac phases acquired in C57BL/6 mice (n = 5). After edge-preserving smoothing with a novel adaptation of 4D bilateral filtration, one phase within each cardiac sequence was manually segmented. Deformable registration was used to propagate these labels to all other cardiac phases for segmentation. The volumes of each cardiac chamber were calculated and used to derive stroke volume, ejection fraction, cardiac output, and cardiac index. Dice coefficients and volume accuracies were used to compare manual segmentations of two additional phases with their corresponding propagated labels. Both measures were, on average, >0.90 for the left ventricle and >0.80 for the myocardium, the right ventricle, and the right atrium, consistent with trends in inter- and intra-segmenter variability. Segmentation of the left atrium was less reliable. On average, the functional metrics of interest were underestimated by 6.76% or more due to systematic label propagation errors around atrioventricular valves; however, execution of the pipeline was 80% faster than performing analogous manual segmentation of each phase. PMID:22971564

Clark, Darin; Badea, Alexandra; Liu, Yilin; Johnson, G. Allan; Badea, Cristian T.

2013-01-01

352

Comparative analysis of geodynamic activity of the Caucasian and Eastern Mediterranean segments of the Alpine-Himalayan convergence zone  

NASA Astrophysics Data System (ADS)

The Alpine-Himalayan convergence zone (AHCZ) underwent recent transverse shortening under the effect of collisional compression. The process was accompanied by rotation of separate microplates. The Caucasian and Eastern Mediterranean regions are segments of the of the AHCZ and are characterized by intensive endogenous and exogenous geodynamic processes, which manifest themselves in occurrence of powerful (with magnitude of 8-9) earthquakes accompanied by development of secondary catastrophic processes. Large landslides, rock falls, avalanches, mud flows, etc. cause human deaths and great material losses. The development of the aforesaid endogenous processes is set forth by peculiarities of the deep structure of the region and an impact of deep geological processes. The Caucasus is divided into several main tectonic terranes: platform (sub-platform, quasi-platform) and fold-thrust units. Existing data enable to perform a division of the Caucasian region into two large-scale geological provinces: southern Tethyan and northern Tethyan located to the south of and to the north of the Lesser Caucasian ophiolite suture, respectively. The recent investigations show that the assessments of the seismic hazard in these regions are not quite correct - for example in the West Caucasus the seismic hazard can be significantly underestimated, which affects the corresponding risk assessments. Integrated analysis of gravity, magnetic, seismic and thermal data enables to refine the assessment of the seismic hazard of the region, taking into account real rates of the geodynamic movements. Important role play the last rheological constructions. According to Reilinger et al. (2006) tectonic scheme, the West flanking of the Arabian Plate manifests strike-slip motion, when the East Caucasian block is converging and shortening. The Eastern Mediterranean is a tectonically complex region located in the midst of the progressive Afro-Eurasian collision. The recent increasing geotectonic activity in this region highlights the need for combined analysis of seismo-neotectonic signatures. For this purpose, this article presents the key features of the tectonic zonation of the Eastern Mediterranean. Map of derivatives of the gravity field retracked from the Geosat satellite and novel map of the Moho discontinuity illustrate the most important tectonic features of the region. The Post-Jurassic map of the deformation of surface leveling reflects the modern tectonic stage of Eastern Mediterranean evolution. The developed tectono-geophysical zonation map integrates the potential geophysical field analysis and seismic section utilization, as well as tectonic-structural, paleogeographical and facial analyses. Tectonically the map agrees with the earlier model of continental accretion (Ben-Avraham and Ginzburg, 1990). Overlaying the seismicity map of the Eastern Mediterranean tectonic region (for the period between 1900 and 2012) on the tectonic zonation chart reveals the key features of the seismo-neotectonic pattern of the Eastern Mediterranean. The results have important implications for tectonic-seismological analysis in this region (Eppelbaum and Katz, 2012). A difference in the geotectonic patterns makes interesting comparison of geodynamic activity and seismic hazard of the Caucasian and Eastern Mediterranean segments of the AHCZ.

Chelidze, Tamaz; Eppelbaum, Lev

2013-04-01

353

STS-1 operational flight profile. Volume 6: Abort analysis  

NASA Technical Reports Server (NTRS)

The abort analysis for the cycle 3 Operational Flight Profile (OFP) for the Space Transportation System 1 Flight (STS-1) is defined, superseding the abort analysis previously presented. Included are the flight description, abort analysis summary, flight design groundrules and constraints, initialization information, general abort description and results, abort solid rocket booster and external tank separation and disposal results, abort monitoring displays and discussion on both ground and onboard trajectory monitoring, abort initialization load summary for the onboard computer, list of the key abort powered flight dispersion analysis.

1980-01-01

354

Adaptive Breast Radiation Therapy Using Modeling of Tissue Mechanics: A Breast Tissue Segmentation Study  

SciTech Connect

Purpose: To validate and compare the accuracy of breast tissue segmentation methods applied to computed tomography (CT) scans used for radiation therapy planning and to study the effect of tissue distribution on the segmentation accuracy for the purpose of developing models for use in adaptive breast radiation therapy. Methods and Materials: Twenty-four patients receiving postlumpectomy radiation therapy for breast cancer underwent CT imaging in prone and supine positions. The whole-breast clinical target volume was outlined. Clinical target volumes were segmented into fibroglandular and fatty tissue using the following algorithms: physical density thresholding; interactive thresholding; fuzzy c-means with 3 classes (FCM3) and 4 classes (FCM4); and k-means. The segmentation algorithms were evaluated in 2 stages: first, an approach based on the assumption that the breast composition should be the same in both prone and supine position; and second, comparison of segmentation with tissue outlines from 3 experts using the Dice similarity coefficient (DSC). Breast datasets were grouped into nonsparse and sparse fibroglandular tissue distributions according to expert assessment and used to assess the accuracy of the segmentation methods and the agreement between experts. Results: Prone and supine breast composition analysis showed differences between the methods. Validation against expert outlines found significant differences (P<.001) between FCM3 and FCM4. Fuzzy c-means with 3 classes generated segmentation results (mean DSC = 0.70) closest to the experts' outlines. There was good agreement (mean DSC = 0.85) among experts for breast tissue outlining. Segmentation accuracy and expert agreement was significantly higher (P<.005) in the nonsparse group than in the sparse group. Conclusions: The FCM3 gave the most accurate segmentation of breast tissues on CT data and could therefore be used in adaptive radiation therapy-based on tissue modeling. Breast tissue segmentation methods should be used with caution in patients with sparse fibroglandular tissue distribution.

Juneja, Prabhjot, E-mail: Prabhjot.Juneja@icr.ac.uk [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom)] [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom); Harris, Emma J. [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom)] [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom); Kirby, Anna M. [Department of Academic Radiotherapy, Royal Marsden National Health Service Foundation Trust, Sutton (United Kingdom)] [Department of Academic Radiotherapy, Royal Marsden National Health Service Foundation Trust, Sutton (United Kingdom); Evans, Philip M. [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom)] [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom)

2012-11-01

355

Space tug economic analysis study. Volume 2: Tug concepts analysis. Part 2: Economic analysis  

NASA Technical Reports Server (NTRS)

An economic analysis of space tug operations is presented. The subjects discussed are: (1) cost uncertainties, (2) scenario analysis, (3) economic sensitivities, (4) mixed integer programming formulation of the space tug problem, and (5) critical parameters in the evaluation of a public expenditure.

1972-01-01

356

Patterns of magma ow in segmented silicic dikes at Summer Coon volcano, Colorado: AMS and thin section analysis  

E-print Network

Patterns of magma £ow in segmented silicic dikes at Summer Coon volcano, Colorado: AMS and thin of a radial swarm at Summer Coon, an eroded stratovolcano in southern Colorado. The two intrusions are broken

357

Analysis of the Wnt gene repertoire in an onychophoran provides new insights into the evolution of segmentation  

PubMed Central

Background The Onychophora are a probable sister group to Arthropoda, one of the most intensively studied animal phyla from a developmental perspective. Pioneering work on the fruit fly Drosophila melanogaster and subsequent investigation of other arthropods has revealed important roles for Wnt genes during many developmental processes in these animals. Results We screened the embryonic transcriptome of the onychophoran Euperipatoides kanangrensis and found that at least 11 Wnt genes are expressed during embryogenesis. These genes represent 11 of the 13 known subfamilies of Wnt genes. Conclusions Many onychophoran Wnt genes are expressed in segment polarity gene-like patterns, suggesting a general role for these ligands during segment regionalization, as has been described in arthropods. During early stages of development, Wnt2, Wnt4, and Wnt5 are expressed in broad multiple segment-wide domains that are reminiscent of arthropod gap and Hox gene expression patterns, which suggests an early instructive role for Wnt genes during E. kanangrensis segmentation. PMID:24708787

2014-01-01

358

Space shuttle navigation analysis. Volume 2: Baseline system navigation  

NASA Technical Reports Server (NTRS)

Studies related to the baseline navigation system for the orbiter are presented. The baseline navigation system studies include a covariance analysis of the Inertial Measurement Unit calibration and alignment procedures, postflight IMU error recovery for the approach and landing phases, on-orbit calibration of IMU instrument biases, and a covariance analysis of entry and prelaunch navigation system performance.

Jones, H. L.; Luders, G.; Matchett, G. A.; Rains, R. G.

1980-01-01

359

A Finite-Volume "Shaving" Method for Interfacing NASA/DAO''s Physical Space Statistical Analysis System to the Finite-Volume GCM with a Lagrangian Control-Volume Vertical Coordinate  

NASA Technical Reports Server (NTRS)

Toward the development of a finite-volume Data Assimilation System (fvDAS), a consistent finite-volume methodology is developed for interfacing the NASA/DAO's Physical Space Statistical Analysis System (PSAS) to the joint NASA/NCAR finite volume CCM3 (fvCCM3). To take advantage of the Lagrangian control-volume vertical coordinate of the fvCCM3, a novel "shaving" method is applied to the lowest few model layers to reflect the surface pressure changes as implied by the final analysis. Analysis increments (from PSAS) to the upper air variables are then consistently put onto the Lagrangian layers as adjustments to the volume-mean quantities during the analysis cycle. This approach is demonstrated to be superior to the conventional method of using independently computed "tendency terms" for surface pressure and upper air prognostic variables.

Lin, Shian-Jiann; DaSilva, Arlindo; Atlas, Robert (Technical Monitor)

2001-01-01

360

Metric Learning to Enhance Hyperspectral Image Segmentation  

NASA Technical Reports Server (NTRS)

Unsupervised hyperspectral image segmentation can reveal spatial trends that show the physical structure of the scene to an analyst. They highlight borders and reveal areas of homogeneity and change. Segmentations are independently helpful for object recognition, and assist with automated production of symbolic maps. Additionally, a good segmentation can dramatically reduce the number of effective spectra in an image, enabling analyses that would otherwise be computationally prohibitive. Specifically, using an over-segmentation of the image instead of individual pixels can reduce noise and potentially improve the results of statistical post-analysis. In this innovation, a metric learning approach is presented to improve the performance of unsupervised hyperspectral image segmentation. The prototype demonstrations attempt a superpixel segmentation in which the image is conservatively over-segmented; that is, the single surface features may be split into multiple segments, but each individual segment, or superpixel, is ensured to have homogenous mineralogy.

Thompson, David R.; Castano, Rebecca; Bue, Brian; Gilmore, Martha S.

2013-01-01

361

Measurement and analysis of grain boundary grooving by volume diffusion  

NASA Technical Reports Server (NTRS)

Experimental measurements of isothermal grain boundary grooving by volume diffusion are carried out for Sn bicrystals in the Sn-Pb system near the eutectic temperature. The dimensions of the groove increase with a temporal exponent of 1/3, and measurement of the associated rate constant allows the determination of the product of the liquid diffusion coefficient D and the capillarity length Gamma associated with the interfacial free energy of the crystal-melt interface. The small-slope theory of Mullins is generalized to the entire range of dihedral angles by using a boundary integral formulation of the associated free boundary problem, and excellent agreement with experimental groove shapes is obtained. By using the diffusivity measured by Jordon and Hunt, the present measured values of Gamma are found to agree to within 5 percent with the values obtained from experiments by Gunduz and Hunt on grain boundary grooving in a temperature gradient.

Hardy, S. C.; Mcfadden, G. B.; Coriell, S. R.; Voorhees, P. W.; Sekerka, R. F.

1991-01-01

362

Particle filtration: An analysis using the method of volume averaging  

SciTech Connect

The process of filtration of non-charged, submicron particles is analyzed using the method of volume averaging. The particle continuity equation is represented in terms of the first correction to the Smoluchowski equation that takes into account particle inertia effects for small Stokes numbers. This leads to a cellular efficiency that contains a minimum in the efficiency as a function of the particle size, and this allows us to identify the most penetrating particle size. Comparison of the theory with results from Brownian dynamics indicates that the first correction to the Smoluchowski equation gives reasonable results in terms of both the cellular efficiency and the most penetrating particle size. However, the results for larger particles clearly indicate the need to extend the Smoluchowski equation to include higher order corrections. Comparison of the theory with laboratory experiments, in the absence of adjustable parameters, provides interesting agreement for particle diameters that are equal to or less than the diameter of the most penetrating particle.

Quintard, M. [L.E.P.T.-ENSAM (UA CNRS), Talence (France); Whitaker, S. [Univ. of California, Davis, CA (United States). Dept. of Chemical Engineering

1994-12-01

363

Segmentation Of Polarimetric SAR Data  

NASA Technical Reports Server (NTRS)

Report presents one in continuing series of studies of segmentation of polarimetric synthetic-aperture-radar, SAR, image data into regions. Studies directed toward refinement of method of automated analysis of SAR data.

Rignot, Eric J. M.; Chellappa, Rama

1994-01-01

364

Random harmonic analysis program, L221 (TEV156). Volume 2: Supplemental system design and maintenenace document  

NASA Technical Reports Server (NTRS)

Volume 2 of a two volume document is presented. A computer program, L222 (TEV 156), available for execution on the CDC 6600 computer is described. The program is capable of calculating steady-state solutions for linear second-order differential equations due to sinusoidal forcing functions. From this, steady-state solutions, generalized coordinates, and load frequency responses may be determined. Statistical characteristics of loads for the forcing function spectral shape may also be calculated using random harmonic analysis techniques. The particular field of application of the program is the analysis of airplane response and loads due to continuous random air turbulence.

Graham, M. L.; Clemmons, R. E.; Miller, R. D.

1979-01-01

365

Image segmentation through reasoning about optics  

E-print Network

Image segmentation through reasoning about optics Bruce A. Maxwell University of North Dakota Grand, and most important tasks in single image analysis is segmentation: grouping pixels that appear to "belong" together. A segmentation provides regions of an image that can be reasoned about and analyzed as a whole

Maxwell, Bruce

366

Estimating Image Segmentation Difficulty Dingding Liu  

E-print Network

Estimating Image Segmentation Difficulty Dingding Liu Yingen Xiong Kari Pulli Linda Shapiro has produced a market for mobile image analysis, including image segmentation to separate out objects of interest. Auto- matic image segmentation algorithms, when employed by many different users for multiple

Shapiro, Linda

367

Demand modelling of passenger air travel: An analysis and extension, volume 2  

NASA Technical Reports Server (NTRS)

Previous intercity travel demand models in terms of their ability to predict air travel in a useful way and the need for disaggregation in the approach to demand modelling are evaluated. The viability of incorporating non-conventional factors (i.e. non-econometric, such as time and cost) in travel demand forecasting models are determined. The investigation of existing models is carried out in order to provide insight into their strong points and shortcomings. The model is characterized as a market segmentation model. This is a consequence of the strengths of disaggregation and its natural evolution to a usable aggregate formulation. The need for this approach both pedagogically and mathematically is discussed. In addition this volume contains two appendices which should prove useful to the non-specialist in the area.

Jacobson, I. D.

1978-01-01

368

A Bland-Altman Analysis of the Bias Between Computed Tomography and Ultrasound Prostate Volume Measurements  

SciTech Connect

This study assesses the agreement between computed tomography (CT) measurements of prostate volume and those obtained by ultrasound (US), a well-established non-invasive technique. Twenty-six patients aged between 58 and 74 years were evaluated for prostate seed implant therapy using both CT and US measurements. The level of agreement between these 2 methods, which were strongly correlated (R{sup 2} = 0.828; p < 0.0001), was determined through Bland-Altman analysis. The mean prostate volume ({+-} one standard deviation) of the sample was 31.8 {+-} 10.5 cc for the CT method and 27.0 {+-} 8.2 cc for the US method. The prostate volumes obtained by CT were, on average, 17% larger than the corresponding volumes determined by US. The average bias between the 2 imaging methods is 4.80 cc or 15%, which is significantly larger than the clinically acceptable margin of 10%.

Gloi, Aime [Department of Radiation Oncology, St. Vincent Hospital, Green Bay, WI (United States)], E-mail: agloi@stvgb.org; McCourt, Stephen; Zuge, Corrie; Goettler, AnnDrea; Schlise, Sally; Cooley, Greg [Department of Radiation Oncology, St. Vincent Hospital, Green Bay, WI (United States)

2008-10-01

369

A phonetic-context controlled strategy for segmentation and phonetic labeling of speech  

Microsoft Academic Search

This paper considers a sequential strategy for acoustic-phonetic speech analysis. Each analysis process is applied to an appropriately labeled speech segment and results in a possible sub-segmentation of the original segment. The segments resulting from the analysis are labeled according to the analysis results. The advantages of the strategy are that no more segments are considered than those actually differentiated

P. Mermelstein

1975-01-01

370

Example based lesion segmentation  

NASA Astrophysics Data System (ADS)

Automatic and accurate detection of white matter lesions is a significant step toward understanding the progression of many diseases, like Alzheimer's disease or multiple sclerosis. Multi-modal MR images are often used to segment T2 white matter lesions that can represent regions of demyelination or ischemia. Some automated lesion segmentation methods describe the lesion intensities using generative models, and then classify the lesions with some combination of heuristics and cost minimization. In contrast, we propose a patch-based method, in which lesions are found using examples from an atlas containing multi-modal MR images and corresponding manual delineations of lesions. Patches from subject MR images are matched to patches from the atlas and lesion memberships are found based on patch similarity weights. We experiment on 43 subjects with MS, whose scans show various levels of lesion-load. We demonstrate significant improvement in Dice coefficient and total lesion volume compared to a state of the art model-based lesion segmentation method, indicating more accurate delineation of lesions.

Roy, Snehashis; He, Qing; Carass, Aaron; Jog, Amod; Cuzzocreo, Jennifer L.; Reich, Daniel S.; Prince, Jerry; Pham, Dzung

2014-03-01

371

Microfabrication of a Segmented-Involute-Foil Regenerator, Testing in a Sunpower Stirling Convertor and Supporting Modeling and Analysis  

NASA Technical Reports Server (NTRS)

Under Phase II of a NASA Research Award contract, a prototype nickel segmented-involute-foil regenerator was microfabricated via LiGA and tested in the NASA/Sunpower oscillating-flow test rig. The resulting figure-of-merit was about twice that of the approx.90% porosity random-fiber material currently used in the small 50-100 W Stirling engines recently manufactured for NASA. That work was reported at the 2007 International Energy Conversion Engineering Conference in St. Louis, was also published as a NASA report, NASA/TM-2007-2149731, and has been more completely described in a recent NASA Contractor Report, NASA/CR-2007-2150062. Under a scaled-back version of the original Phase III plan, a new nickel segmentedinvolute- foil regenerator was microfabricated and has been tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator been made from a low-conductivity material. Also the FTB convertor was not reoptimized to take full advantage of the microfabricated regenerator's low flow resistance; thus the efficiency would likely have been even higher had the FTB been completely reoptimized. This report discusses the regenerator microfabrication process, testing of the regenerator in the Stirling FTB convertor, and the supporting analysis. Results of the pre-test computational fluid dynamics (CFD) modeling of the effects of the regenerator-test-configuration diffusers (located at each end of the regenerator) is included. The report also includes recommendations for accomplishing further development of involute-foil regenerators from a higher-temperature material than nickel.

Ibrahim, Mounir B.; Tew, Roy C.; Gedeon, David; Wood, Gary; McLean, Jeff

2008-01-01

372

Ceramic component development analysis -- Volume 1. Final report  

SciTech Connect

The development of advanced filtration media for advanced fossil-fueled power generating systems is a critical step in meeting the performance and emissions requirements for these systems. While porous metal and ceramic candle-filters have been available for some time, the next generation of filters will include ceramic-matrix composites (CMCs) (Techniweave/Westinghouse, Babcock and Wilcox (B and W), DuPont Lanxide Composites), intermetallic alloys (Pall Corporation), and alternate filter geometries (CeraMem Separations). The goal of this effort was to perform a cursory review of the manufacturing processes used by 5 companies developing advanced filters from the perspective of process repeatability and the ability for their processes to be scale-up to produce volumes. Given the brief nature of the on-site reviews, only an overview of the processes and systems could be obtained. Each of the 5 companies had developed some level of manufacturing and quality assurance documentation, with most of the companies leveraging the procedures from other products they manufacture. It was found that all of the filter manufacturers had a solid understanding of the product development path. Given that these filters are largely developmental, significant additional work is necessary to understand the process-performance relationships and projecting manufacturing costs.

Boss, D.E.

1998-06-09

373

SLUDGE TREATMENT PROJECT ALTERNATIVES ANALYSIS SUMMARY REPORT [VOLUME 1  

SciTech Connect

Highly radioactive sludge (containing up to 300,000 curies of actinides and fission products) resulting from the storage of degraded spent nuclear fuel is currently stored in temporary containers located in the 105-K West storage basin near the Columbia River. The background, history, and known characteristics of this sludge are discussed in Section 2 of this report. There are many compelling reasons to remove this sludge from the K-Basin. These reasons are discussed in detail in Section1, and they include the following: (1) Reduce the risk to the public (from a potential release of highly radioactive material as fine respirable particles by airborne or waterborn pathways); (2) Reduce the risk overall to the Hanford worker; and (3) Reduce the risk to the environment (the K-Basin is situated above a hazardous chemical contaminant plume and hinders remediation of the plume until the sludge is removed). The DOE-RL has stated that a key DOE objective is to remove the sludge from the K-West Basin and River Corridor as soon as possible, which will reduce risks to the environment, allow for remediation of contaminated areas underlying the basins, and support closure of the 100-KR-4 operable unit. The environmental and nuclear safety risks associated with this sludge have resulted in multiple legal and regulatory remedial action decisions, plans,and commitments that are summarized in Table ES-1 and discussed in more detail in Volume 2, Section 9.

FREDERICKSON JR; ROURK RJ; HONEYMAN JO; JOHNSON ME; RAYMOND RE

2009-01-19

374

Numerical analysis of volume holograms with spherical reference wave based on Born approximation  

NASA Astrophysics Data System (ADS)

Holographic Data Storage (HDS) is one of the next generation storage technologies that can actualize high data capacity and high data transfer rate. Since information is recorded 3-dimensionally in a thick medium, data capacity of the HDS is not constrained by diffraction limit. However, behavior of wavefront in an inhomogeneous thick medium is highly complex, and it is hard to handle propagation of wavefront in the medium analytically. Therefore, we establish a numerical technique for analysis of volume holograms. The proposed technique is based on the scalar diffraction theory, which is described as the volume integral equation. By applying Born approximation and angular spectrum method to the volume integral equation, the technique can be applicable for various problems. We analyze characteristics of the volume hologram with spherical reference wave, and confirm effectiveness of the proposed technique. Compared to conventional techniques such as coupled wave analysis, beam propagation method, and finite-difference time domain method, the proposed technique has application potentiality for various problems, and it is easy to implement. In this study, we show effectiveness of the proposed technique by applying to analysis of the volume hologram with spherical reference wave. It can be expected that the proposed technique may become a tool for design of HDS systems.

Yoshida, S.; Yamamoto, M.

2013-05-01

375

Finite element analysis of laminated plates and shells, volume 1  

NASA Technical Reports Server (NTRS)

The finite element method is used to investigate the static behavior of laminated composite flat plates and cylindrical shells. The analysis incorporates the effects of transverse shear deformation in each layer through the assumption that the normals to the undeformed layer midsurface remain straight but need not be normal to the mid-surface after deformation. A digital computer program was developed to perform the required computations. The program includes a very efficient equation solution code which permits the analysis of large size problems. The method is applied to the problem of stretching and bending of a perforated curved plate.

Seide, P.; Chang, P. N. H.

1978-01-01

376

Segmented testing  

NASA Technical Reports Server (NTRS)

The fraction of faults detected for a digital network is frequently high for the first few input combinations applied out of a set of test vectors. When the particular ordering of test patterns does not appreciably change the shape of the coverage curve, there appears to be an advantage to splitting the test into segments which are applied at different times. It is shown that the expected time to error detection and the probability of an undetected double error can be reduced. The amount of reduction is dependent on the shape of the fault coverage curve. It is conjectured that such a reduction can be obtained for VLSI networks.

Robinson, J. P.

1985-01-01

377

Segmented testing  

NASA Technical Reports Server (NTRS)

The fraction of faults detected for a digital network is frequently high for the first few input combinations applied out of a set of test vectors. When the particular ordering of test patterns does not appreciably change the shape of the coverage curve, there appears to be an advantage to splitting the test into segments which are applied at different times. It is shown that the expected time to error detection and the probability of an undetected double error can be reduced. The amount of reduction is dependent on the shape of the fault coverage curve. It is conjectured that such a reduction can be obtained for VLSI networks.

Robinson, J. P.

1984-01-01

378

Segmental neurofibromatosis  

PubMed Central

Segmental neurofibromatosis or type V neurofibromatosis is a rare genodermatosis characterized by neurofibromas, café-au-lait spots and neurofibromas limited to a circumscribed body region. The disease may be associated with systemic involvement and malignancies. The disorder has not been reported yet in the Polish medical literature. A 63-year-old Caucasian woman presented with a 20-year history of multiple, flesh colored, dome-shaped, soft to firm nodules situated in the right lumbar region. A histopathologic evaluation of three excised tumors revealed neurofibromas. No neurological and ophthalmologic symptoms of neurofibromatosis were diagnosed. PMID:25610358

Dobosz-Kawa?ko, Magdalena; Michaj?owski, Igor; P?ksa, Rafa?; Nowicki, Roman

2014-01-01

379

Automatic 3-D Grayscale Volume Matching and Shape Analysis  

Microsoft Academic Search

Recently, shape matching in three dimensions (3-D) has been gaining importance in a wide variety of fields such as computer graphics, computer vision, medicine, and biology, with applications such as object recognition, medical diagnosis, and quantitative morphological analysis of biological operations. Automatic shape matching techniques developed in the field of computer graphics handle object surfaces, but ignore intensities of inner

Gregoire Guetat; Matthieu Maitre; Laurene Joly; Sen-lin Lai; Tzumin Lee; Yoshihisa Shinagawa

2006-01-01

380

Quantitative analysis of volume images -electron microscopic tomography of HIV  

E-print Network

viruses to non-infectious ones. 2 THE APPLICATION The HIV has the geometry of a sphere with a diameter to assist in the structural analysis of the causative virus of the AIDS disease, HIV. Especially interesting is a study of the internal morphology of the virus at di#11;erent stages and a comparison of infectious

Nyström, Ingela

381

Generic method for automatic bladder segmentation on cone beam CT using a patient-specific bladder shape model  

SciTech Connect

Purpose: The aim of this study is to develop and validate a generic method for automatic bladder segmentation on cone beam computed tomography (CBCT), independent of gender and treatment position (prone or supine), using only pretreatment imaging data. Methods: Data of 20 patients, treated for tumors in the pelvic region with the entire bladder visible on CT and CBCT, were divided into four equally sized groups based on gender and treatment position. The full and empty bladder contour, that can be acquired with pretreatment CT imaging, were used to generate a patient-specific bladder shape model. This model was used to guide the segmentation process on CBCT. To obtain the bladder segmentation, the reference bladder contour was deformed iteratively by maximizing the cross-correlation between directional grey value gradients over the reference and CBCT bladder edge. To overcome incorrect segmentations caused by CBCT image artifacts, automatic adaptations were implemented. Moreover, locally incorrect segmentations could be adapted manually. After each adapted segmentation, the bladder shape model was expanded and new shape patterns were calculated for following segmentations. All available CBCTs were used to validate the segmentation algorithm. The bladder segmentations were validated by comparison with the manual delineations and the segmentation performance was quantified using the Dice similarity coefficient (DSC), surface distance error (SDE) and SD of contour-to-contour distances. Also, bladder volumes obtained by manual delineations and segmentations were compared using a Bland-Altman error analysis. Results: The mean DSC, mean SDE, and mean SD of contour-to-contour distances between segmentations and manual delineations were 0.87, 0.27 cm and 0.22 cm (female, prone), 0.85, 0.28 cm and 0.22 cm (female, supine), 0.89, 0.21 cm and 0.17 cm (male, supine) and 0.88, 0.23 cm and 0.17 cm (male, prone), respectively. Manual local adaptations improved the segmentation results significantly (p < 0.01) based on DSC (6.72%) and SD of contour-to-contour distances (0.08 cm) and decreased the 95% confidence intervals of the bladder volume differences. Moreover, expanding the shape model improved the segmentation results significantly (p < 0.01) based on DSC and SD of contour-to-contour distances. Conclusions: This patient-specific shape model based automatic bladder segmentation method on CBCT is accurate and generic. Our segmentation method only needs two pretreatment imaging data sets as prior knowledge, is independent of patient gender and patient treatment position and has the possibility to manually adapt the segmentation locally.

Schoot, A. J. A. J. van de, E-mail: a.j.schootvande@amc.uva.nl; Schooneveldt, G.; Wognum, S.; Stalpers, L. J. A.; Rasch, C. R. N.; Bel, A. [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands)] [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Hoogeman, M. S. [Department of Radiation Oncology, Daniel den Hoed Cancer Center, Erasmus Medical Center, Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands)] [Department of Radiation Oncology, Daniel den Hoed Cancer Center, Erasmus Medical Center, Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands); Chai, X. [Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Palo Alto, California 94305 (United States)] [Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Palo Alto, California 94305 (United States)

2014-03-15

382

On 3-D inelastic analysis methods for hot section components. Volume 1: Special finite element models  

NASA Technical Reports Server (NTRS)

This Annual Status Report presents the results of work performed during the third year of the 3-D Inelastic Analysis Methods for Hot Section Components program (NASA Contract NAS3-23697). The objective of the program is to produce a series of new computer codes that permit more accurate and efficient three-dimensional analysis of selected hot section components, i.e., combustor liners, turbine blades, and turbine vanes. The computer codes embody a progression of mathematical models and are streamlined to take advantage of geometrical features, loading conditions, and forms of material response that distinguish each group of selected components. This report is presented in two volumes. Volume 1 describes effort performed under Task 4B, Special Finite Element Special Function Models, while Volume 2 concentrates on Task 4C, Advanced Special Functions Models.

Nakazawa, S.

1987-01-01

383

Segmented binary control of multi-axis SMA array actuators  

Microsoft Academic Search

A new approach to designing and controlling multiple artificial muscle actuators using Segmented Binary Control (SBC) is presented and is implemented using shape memory alloys (SMA). SMA actuators are segmented into many independently controlled, spatially discrete volumes, each contributing a small displacement to create a large motion. The segmented architecture of SMA wires is extended to a multi-axis actuator array

Kyu-Jin Cho; Brian Selden; H. Harry Asada

2005-01-01

384

Stochastic watershed segmentation Jess Angulo and Dominique Jeulin  

E-print Network

Stochastic watershed segmentation Jesús Angulo and Dominique Jeulin Centre de Morphologie.angulo,dominique.jeulin@ensmp.fr Abstract This paper introduces a watershed-based stochastic segmentation methodology. The approach is based is then segmented by volumic watershed for den- ing the R most signicant regions. It over-performs the standard

Angulo,Jesús

385

Space tug economic analysis study. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

An economic analysis of space tug operations is presented. The space tug is defined as any liquid propulsion stage under 100,000 pounds propellant loading that is flown from the space shuttle cargo bay. Two classes of vehicles are the orbit injection stages and reusable space tugs. The vehicle configurations, propellant combinations, and operating modes used for the study are reported. The summary contains data on the study approach, results, conclusions, and recommendations.

1972-01-01

386

Structural analysis of cylindrical thrust chambers, volume 3  

NASA Technical Reports Server (NTRS)

A system of three computer programs is described for use in conjunction with the BOPAGE finite element program. The programs are demonstrated by analyzing cumulative plastic deformation in a regeneratively cooled rocket thrust chamber. The codes provide the capability to predict geometric and material nonlinear behavior of cyclically loaded structures without performing a cycle-by-cycle analysis over the life of the structure. The program set consists of a BOPACE restart tape reader routine, and extrapolation program and a plot package.

Pearson, M. L.

1981-01-01

387

nature genetics volume 25 june 2000 239 Gene Index analysis of the human genome estimates  

E-print Network

letter nature genetics · volume 25 · june 2000 239 Gene Index analysis of the human genome should be addressed to J.Q. (e-mail: johnq@tigr.org). Although sequencing of the human genome will soon,000,000 human ESTs in dbEST provide an important resource for gene identification and genome annota- tion

Salzberg, Steven

388

Waste Isolation Pilot Plant Geotechnical Analysis Report for July 2005 - June 2006, Volume 2, Supporting Data  

SciTech Connect

This report is a compilation of geotechnical data presented as plots for each active instrument installed in the underground at the Waste Isolation Pilot Plant (WIPP) through June 30, 2006. A summary of the geotechnical analyses that were performed using the enclosed data is provided in Volume 1 of the Geotechnical Analysis Report (GAR).

Washington TRU Solutions LLC

2007-03-25

389

Automotive manufacturing assessment system. Volume IV: engine manufacturing analysis. Final report Jun 77Aug 78  

Microsoft Academic Search

Volume IV represents the results of one of four major study areas under the Automotive Manufacturing Assessment System (AMAS) sponsored by the DOT\\/Transportation Systems Center. AMAS was designed to assist in the evaluation of industry's capability to produce fuel efficient vehicles. An analysis of automotive engine manufacturing was conducted in order to determine the impact of regulatory changes on tooling

T. Jr

1979-01-01

390

CRIME PATTERNS AND ANALYSIS VOLUME 3, NUMBER 1 51 SIMULATING THE DYNAMICAL INTERACTION OF  

E-print Network

and spatial dynamics of such offender, target and guardian processes is paramount for the occurrence of crimeCRIME PATTERNS AND ANALYSIS VOLUME 3, NUMBER 1 51 SIMULATING THE DYNAMICAL INTERACTION OF OFFENDERS Within the routine activity paradigm (Cohen & Felson, 1979; Felson, 2008), it is argued that crime takes

Bosse, Tibor

391

The Journal of Fourier Analysis and Applications Volume 4, Issue 6, 1998  

E-print Network

support contained in E U F. Our technique applies, in particular, to the Shannon and Journe wavelet setsThe Journal of Fourier Analysis and Applications Volume 4, Issue 6, 1998 On Wavelet Sets Eugen J that associated with every wavelet set is a closely related "regularized" wavelet set which has very nice

Larson, David R.

392

Chemical laser systems: An engineering approach. Volume 1: Chemical laser analysis program  

Microsoft Academic Search

The Chemical Laser Analysis Program presented in this report is a computer program for the rapid, parametric evaluation of high energy, chemical laser systems, including the combustion chemistry, laser devices gas dynamics, various diffuser-ejector pressure recovery subsystems, and system volume\\/mass estimates. The program does not calculate specific laser power but relies on experimental data for scaling information. The FORTRAN EXTENDED

C. D. Mikkelsen; B. J. Walker

1979-01-01

393

Chemical laser systems: an engineering approach. Volume I. Chemical laser analysis program. Technical report  

Microsoft Academic Search

The Chemical Laser Analysis Program presented in this report is a computer program for the rapid, parametric evaluation of high energy, chemical laser systems including the combustion chemistry, laser devices gas dynamics, various diffuser-ejector pressure recovery subsystems, and system volume\\/mass estimates. The program does not calculate specific laser power but relies on experimental data for scaling information. The FORTRAN EXTENDED

C. D. Mikkelsen; B. J. Walker

1979-01-01

394

A STANDARD PROCEDURE FOR COST ANALYSIS OF POLLUTION CONTROL OPERATIONS. VOLUME I. USER GUIDE  

EPA Science Inventory

Volume I is a user guide for a standard procedure for the engineering cost analysis of pollution abatement operations and processes. The procedure applies to projects in various economic sectors: private, regulated, and public. The models are consistent with cost evaluation pract...

395

Fast Analysis of Intracranial Aneurysms based on Interactive Direct Volume Rendering and CTA  

E-print Network

Fast Analysis of Intracranial Aneurysms based on Interactive Direct Volume Rendering and CTA P of intracranial aneurysms and the planning of related interventions is effectively assisted by spiral CT and aneurysms directly within the 3D viewer. Thereby, the expensive material required for coil- ing procedures

Blanz, Volker

396

SOLVENT-BASED TO WATERBASED ADHESIVE-COATED SUBSTRATE RETROFIT - VOLUME I: COMPARATIVE ANALYSIS  

EPA Science Inventory

This volume represents the analysis of case study facilities' experience with waterbased adhesive use and retrofit requirements. (NOTE: The coated and laminated substrate manufacturing industry was selected as part of NRMRL'S support of the 33/50 Program because of its significan...

397

Volume 15, number 5 June/July 2010 markets products analysis research forecasts  

E-print Network

Volume 15, number 5 June/July 2010 highlights markets products analysis research forecasts CliCk here to visit our website (www.woodmarkets.com)! international Wood markets Group inc. is pleased to provide you with an overview of our monthly 12-page WOOD Markets newsletter. The excerpts displayed

398

Volume 15, number 3 april 2010 markets products analysis research forecasts  

E-print Network

Volume 15, number 3 april 2010 highlights markets products analysis research forecasts Cli and fractured. This is a widespread phenomenon that is showing up in many products, channels and markets around the world in almost all wood products. While WOOD MARKETS' supply and demand models have been

399

Journal of Quantitative Analysis in Volume 6, Issue 3 2010 Article 8  

E-print Network

Journal of Quantitative Analysis in Sports Volume 6, Issue 3 2010 Article 8 A Point-Mass Mixture, Blakeley B. McShane, and Shane T. Jensen Abstract A plethora of statistics have been proposed to measure), some have gained currency only recently (e.g., WHIP, K/BB). Some of these metrics may have predictive

Jensen, Shane T.

400

Contrastive Textology: Comparative Discourse Analysis in Applied Linguistics. Studies in Descriptive Linguistics, Volume 5.  

ERIC Educational Resources Information Center

This volume is one in a series of studies in linguistics that is intended to supplement the "International Review of Applied Linguistics." Discourse analysis, or looking at language as text in context, is presented in the first chapter. This is correlated with what is known about the differences between languages in a second chapter on contrastive…

Hartmann, R. R. K.

401

Economic impact of energy shortages on commercial air transportation and aviation manufacture. Volume 1. Impact analysis  

Microsoft Academic Search

The economic impact of energy shortages on commercial air transportation and aviation manufacture is assessed in this study. Volume 1 presents: 1) the impact analysis of energy scarcity on the air transportation industry; and 2) the summary and conclusions of the entire report. Both near-term and long-term effects of energy shortages are investigated. The forces of change at work in

J. E. Gorham; D. Gross; J. C. Snipes

1975-01-01

402

Driver Education Task Analysis. Volume IV: The Development of Instructional Objectives. Final Report.  

ERIC Educational Resources Information Center

This report is the fourth in a series of four reports dealing with the development of performance-oriented driver education objectives through an analysis of the driver's tasks. Described in this volume are the methods used to develop a set of instructional objectives for driver education courses and an evaluation instrument for evaluating…

McKnight, A. James; Hundt, Alan G.

403

Aoristic Signatures and the Spatio-Temporal Analysis of High Volume Crime Patterns  

Microsoft Academic Search

The spatial analysis of crime and the current focus on hotspots has pushed the area of crime mapping to the fore, especially in regard to high volume offenses such as vehicle theft and burglary. Hotspots also have a temporal component, yet police recorded crime databases rarely record the actual time of offense as this is seldom known. Police crime data

Jerry H. Ratcliffe

2002-01-01

404

A generic approach to pathological lung segmentation.  

PubMed

In this study, we propose a novel pathological lung segmentation method that takes into account neighbor prior constraints and a novel pathology recognition system. Our proposed framework has two stages; during stage one, we adapted the fuzzy connectedness (FC) image segmentation algorithm to perform initial lung parenchyma extraction. In parallel, we estimate the lung volume using rib-cage information without explicitly delineating lungs. This rudimentary, but intelligent lung volume estimation system allows comparison of volume differences between rib cage and FC based lung volume measurements. Significant volume difference indicates the presence of pathology, which invokes the second stage of the proposed framework for the refinement of segmented lung. In stage two, texture-based features are utilized to detect abnormal imaging patterns (consolidations, ground glass, interstitial thickening, tree-inbud, honeycombing, nodules, and micro-nodules) that might have been missed during the first stage of the algorithm. This refinement stage is further completed by a novel neighboring anatomy-guided segmentation approach to include abnormalities with weak textures, and pleura regions. We evaluated the accuracy and efficiency of the proposed method on more than 400 CT scans with the presence of a wide spectrum of abnormalities. To our best of knowledge, this is the first study to evaluate all abnormal imaging patterns in a single segmentation framework. The quantitative results show that our pathological lung segmentation method improves on current standards because of its high sensitivity and specificity and may have considerable potential to enhance the performance of routine clinical tasks. PMID:25020069

Mansoor, Awais; Bagci, Ulas; Xu, Ziyue; Foster, Brent; Olivier, Kenneth N; Elinoff, Jason M; Suffredini, Anthony F; Udupa, Jayaram K; Mollura, Daniel J

2014-12-01

405

Analysis of the high water wave volume for the Sava River near Zagreb  

NASA Astrophysics Data System (ADS)

The paper analyses volumes of the Sava River high water waves near Zagreb during the period: 1926-2008 (N = 83 years), which is needed for more efficient control of high and flood waters. The primary Sava flood control structures in the City of Zagreb are dikes built on both riverbanks, and the Odra Relief Canal with lateral spillway upstream from the City of Zagreb. Intensive morphological changes in the greater Sava area near Zagreb, and anthropological and climate variations and changes at the Sava catchment up to the Zagreb area require detailed analysis of the water wave characteristics. In one analysis, maximum annual volumes are calculated for high water waves with constant duration of: 10, 20, 30, 40, 50 and 60 days. Such calculations encompass total quantity of water (basic and surface runoff). The log Pearson III distribution is adapted for this series of maximum annual volumes. Based on the results obtained, the interrelations are established between the wave volume as function of duration and occurrence probability. In addition to the analysis of maximum volumes of constant duration, it is interesting to carry out the analyses of maximum volume in excess of the reference discharge since it is very important for the flood control. To determine the reference discharges, a discharge of specific duration is used from an average discharge duration curve. The adopted reference discharges have durations of 50, 40, 30, 20 and 10%. Like in the previous case, log Pearson III distribution is adapted to the maximum wave data series. For reference discharge Q = 604 m3/s (duration 10%), a linear trend is calculated of maximum annual volumes exceeding the reference discharge for the Sava near Zagreb during the analyzed period. The analysis results show a significant decrease trend. A similar analysis is carried out for the following three reference discharges: regular flood control measures at the Sava near Zagreb, which are proclaimed when the water level is 350 cm (Q = 2114 m3/s), extraordinary flood control measures taken when the water level is 450 cm (Q = 2648 m3/s), and the discharge at the deterministic inlet into the Odra Canal of approximately Q = 2300 m3/s. The results of these analyses have shown that water wave volumes higher than the reference discharges occurred in a comparatively small number of years, and that their duration was one to two days.

Trninic, Dusan

2010-05-01

406

Comparison of gray matter volume and thickness for analysis of cortical changes in Alzheimer's disease  

NASA Astrophysics Data System (ADS)

Gray matter volume and cortical thickness are two indices of concern in brain structure magnetic resonance imaging research. Gray matter volume reflects mixed-measurement information of cerebral cortex, while cortical thickness reflects only the information of distance between inner surface and outer surface of cerebral cortex. Using Scaled Subprofile Modeling based on Principal Component Analysis (SSM_PCA) and Pearson's Correlation Analysis, this study further provided quantitative comparisons and depicted both global relevance and local relevance to comprehensively investigate morphometrical abnormalities in cerebral cortex in Alzheimer's disease (AD). Thirteen patients with AD and thirteen age- and gender-matched healthy controls were included in this study. Results showed that factor scores from the first 8 principal components accounted for ~53.38% of the total variance for gray matter volume, and ~50.18% for cortical thickness. Factor scores from the fifth principal component showed significant correlation. In addition, gray matter voxel-based volume was closely related to cortical thickness alterations in most cortical cortex, especially, in some typical abnormal brain regions such as insula and the parahippocampal gyrus in AD. These findings suggest that these two measurements are effective indices for understanding the neuropathology in AD. Studies using both gray matter volume and cortical thickness can separate the causes of the discrepancy, provide complementary information and carry out a comprehensive description of the morphological changes of brain structure.

Liu, Jiachao; Li, Ziyi; Chen, Kewei; Yao, Li; Wang, Zhiqun; Li, Kunchen; Guo, Xiaojuan

2011-03-01

407

An investigation of wing buffeting response at subsonic and transonic speeds. Phase 1: F-111A flight data analysis. Volume 3: Tabulated power spectra  

NASA Technical Reports Server (NTRS)

Volume 3 of this three volume report is presented. This volume presents power spectral density in tabular form for the convenience of those who might wish to perform additional analysis. Some of the information contained in Volume 1 is again repeated (as in volume 2) in this volume to allow the reader to identify the specific conditions appropriate to each tabular listing and for further analysis.

Benepe, D. B.; Cunningham, A. M., Jr.; Dunmyer, W. D.

1978-01-01

408

Development of a rotorcraft. Propulsion dynamics interface analysis, volume 1  

NASA Technical Reports Server (NTRS)

The details of the modeling process and its implementation approach are presented. A generic methodology and model structure for performing coupled propulsion/rotor response analysis that is applicable to a variety of rotorcraft types was developed. A method for parameterizing the model structure to represent a particular rotorcraft is defined. The generic modeling methodology, the development of the propulsion system and the rotor/fuselage models, and the formulation of the resulting coupled rotor/propulsion system model are described. A test case that was developed is described.

Hull, R.

1982-01-01

409

Lobar analysis of collapsibility indices to assess functional lung volumes in COPD patients  

PubMed Central

Background We investigated correlations between lung volume collapsibility indices and pulmonary function test (PFT) results and assessed lobar differences in chronic obstructive pulmonary disease (COPD) patients, using paired inspiratory and expiratory three dimensional (3D) computed tomography (CT) images. Methods We retrospectively assessed 28 COPD patients who underwent paired inspiratory and expiratory CT and PFT exams on the same day. A computer-aided diagnostic system calculated total lobar volume and emphysematous lobar volume (ELV). Normal lobar volume (NLV) was determined by subtracting ELV from total lobar volume, both for inspiratory phase (NLVI) and for expiratory phase (NLVE). We also determined lobar collapsibility indices: NLV collapsibility ratio (NLVCR) (%) = (1 ? NLVE/NLVI) × 100%. Associations between lobar volumes and PFT results, and collapsibility indices and PFT results were determined by Pearson correlation analysis. Results NLVCR values were significantly correlated with PFT results. Forced expiratory volume in 1 second, measured as percent of predicted results (FEV1%P) was significantly correlated with NLVCR values for the lower lobes (P<0.01), whereas this correlation was not significant for the upper lobes (P=0.05). FEV1%P results were also moderately correlated with inspiratory, expiratory ELV (ELVI,E) for the lower lobes (P<0.05). In contrast, the ratio of the diffusion capacity for carbon monoxide to alveolar gas volume, measured as percent of predicted (DLCO/VA%P) results were strongly correlated with ELVI for the upper lobes (P<0.001), whereas this correlation with NLVCR values was weaker for upper lobes (P<0.01) and was not significant for the lower lobes (P=0.26). Conclusion FEV1%P results were correlated with NLV collapsibility indices for lower lobes, whereas DLCO/VA%P results were correlated with NLV collapsibility indices and ELV for upper lobes. Thus, evaluating lobar NLV collapsibility might be useful for estimating pulmonary function in COPD patients. PMID:25525352

Kitano, Mariko; Iwano, Shingo; Hashimoto, Naozumi; Matsuo, Keiji; Hasegawa, Yoshinori; Naganawa, Shinji

2014-01-01

410

Computed Tomography Colonography Technique: The Role of Intracolonic Gas Volume  

PubMed Central

Introduction. Poor distention decreases the sensitivity and specificity of CTC. The total volume of gas administered will vary according to many factors. We aim to determine the relationship between the volume of retained gas at the time of image acquisition and colonic distention and specifically the presence of collapsed bowel segments at CTC. Materials and Methods. All patients who underwent CTC over a 12-month period at a single institution were included in the study. Colonic luminal distention was objectively scored by 2 radiologists using an established 4-point scale. Quantitative analysis of the volume of retained gas at the time of image acquisition was conducted using the threshold 3D region growing function of OsiriX. Results. 108 patients were included for volumetric analysis. Mean retained gas volume was 3.3?L. 35% (38/108) of patients had at least one collapsed colonic segment. Significantly lower gas volumes were observed in the patients with collapsed colonic segments when compared with those with fully distended colons 2.6?L versus 3.5?L (P = 0.031). Retained volumes were significantly higher for the 78% of patients with ileocecal reflux at 3.4?L versus 2.6?L without ileocecal reflux (P = 0.014). Conclusion. Estimation of intraluminal gas volume at CTC is feasible using image segmentation and thresholding tools. An average of 3.5?L of retained gas was found in diagnostically adequate CTC studies with significantly lower mean gas volume observed in patients with collapsed colonic segments. PMID:24455246

McLaughlin, Patrick D.; Murphy, Kevin P.; Crush, Lee; O'Connor, Owen J.; Coyle, Joseph P.; Brennan, Cressida R.; Suhail, Attiya; Kelly, Denis; Maher, Michael M.

2013-01-01

411

Small V/STOL aircraft analysis, volume 1  

NASA Technical Reports Server (NTRS)

A study has been made of the economic viability of advanced V/STOL aircraft concepts in performing general aviation missions. A survey of general aviation aircraft users, operators, and manufacturers indicated that personnel transport missions formulated around business executive needs, commuter air service, and offshore oil supply are the leading potential areas of application using VTOL aircraft. Advanced VTOL concepts potentially available in the late 1970 time period were evaluated as alternatives to privately owned contemporary aircraft and commercial airline service in satisfying these personnel transport needs. Economic analysis incorporating the traveler's value of time as the principle figure of merit were used to identify the relative merits of alternative VTOL air transportation concepts.

Smith, K. R., Jr.; Belina, F. W.

1974-01-01

412

Low-Dose Micro-CT Imaging for Vascular Segmentation and Analysis Using Sparse-View Acquisitions  

PubMed Central

The aim of this study is to investigate whether reliable and accurate 3D geometrical models of the murine aortic arch can be constructed from sparse-view data in vivo micro-CT acquisitions. This would considerably reduce acquisition time and X-ray dose. In vivo contrast-enhanced micro-CT datasets were reconstructed using a conventional filtered back projection algorithm (FDK), the image space reconstruction algorithm (ISRA) and total variation regularized ISRA (ISRA-TV). The reconstructed images were then semi-automatically segmented. Segmentations of high- and low-dose protocols were compared and evaluated based on voxel classification, 3D model diameters and centerline differences. FDK reconstruction does not lead to accurate segmentation in the case of low-view acquisitions. ISRA manages accurate segmentation with 1024 or more projection views. ISRA-TV needs a minimum of 256 views. These results indicate that accurate vascular models can be obtained from micro-CT scans with 8 times less X-ray dose and acquisition time, as long as regularized iterative reconstruction is used. PMID:23840893

Vandeghinste, Bert; Vandenberghe, Stefaan; Vanhove, Chris; Staelens, Steven; Van Holen, Roel

2013-01-01

413

[cDNA cloning and sequence analysis of genome segment S7 of rice black-streaked dwarf virus].  

PubMed

Genome segments 7 of zhejiang and Hebei isolates of rice black-streaked dwarf virus (RBSDV) were amplified and sequenced. Segment 7 of Zhejiang isolate was consisted of 2193 nts (EMBL accession no. AJ297427) in length and that of Hebei isolate was 2190 nts (AJ297428). Both segments contained two non-overlapping open reading frames (ORFs), which encoded two polypeptides with molecular weights of 41 kD and 36 kD. These two segments shared 99% nucleotide identity, 100% and 94.4% amino acid identities of ORF1 and ORF2, shared 93.5% and 93.8% identities at nucleotide level, 98.1% (ORF1) and 96.5%/97.8% (ORF2) at amino acid level with S7 of Japanese RBSDV, and shared 85.1% and 85.3% identities at nucleotide level, 92.3% (ORF1), 85.5%/86.8% (ORF2) at amino acid level with S6 of Italian MRDV. PMID:12557397

Zhang, Hengmu; Chen, Jianping; Lei, Juanli; Cheng, Ye; Xue, Qingzhong

2002-04-01

414

Analysis of neural elements in head-mutant Drosophila embryos suggests segmental origin of the optic lobes  

Microsoft Academic Search

We describe the development of 20 sensory organs in the embryonic Drosophila head, which give rise to 7 sensory nerves of the peripheral nervous system (PNS), and 4 ganglia of the stomatogastric nervous system (SNS). Using these neural elements and the optic lobes as well as expression domains of the segment polarity gene engrailed in the wild-type head of Drosophila

Urs Schmidt-Ott; Marcos González-Gaitán; Gerhard M. Technau

1995-01-01

415

RFLP analysis of the size of chromosomal segments retained around the Tm2 locus of tomato during backcross breeding  

Microsoft Academic Search

Genes introduced into cultivated plants by backcross breeding programs are flanked by introgressed segments of DNA derived from the donor parent. This phenomenon is known as linkage drag and is frequently thought to affect traits other than the one originally targeted. The Tm-2 gene of Lycopersicon peruvianum, which confers resistance to tobacco mosaic virus, was introduced into several different tomato

N. D. Young; S. D. Tanksley

1989-01-01

416

County: Ada Station # 010 District: 03 Route: SH55 Ascending Direction: North Segment Code and Milepost: 001990 047.830 3.3 Miles North of Jct SH44 (Dry Creek) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 58 0.6% 33 0.4% 32 0.5% 22 0.4% 23 0.3% 34 0.4% 58 0.7% 28 0.4% 58 0.7%

Sunday Monday

2005-01-01

417

Station # 043 District: 03 Route: SH55 Ascending Direction: North Segment Code and Milepost: 001990 127.720 3.6 Miles South of Roseberry Rd (Donnelly) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 11 0.4% 9 0.3% 6 0.2% 9 0.3% 8 0.3% 7 0.2% 12 0.5% 8 0.3% 12 0.4%

Sunday Monday

2009-01-01

418

County: Ada Station # 080 District: 03 Route: SMA 7643 Ascending Direction: North Segment Code and Milepost: 002140 004.144 0.5 Miles South of Warm Springs Ave, Boise (Eckert Road) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 29 1.0% 14 0.4% 9 0.2% 14 0.4% 34 0.9% 16 0.4% 25 0.7% 18 0.5% 27 0.9%

Sunday Monday

2009-01-01

419

County: Idaho Station # 150 District: 02 Route: US95 Ascending Direction: North Segment Code and Milepost: 001540 188.915 5.7 Miles South Salmon River Rd, Riggins (Sheep Creek) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 8 0.3% 9 0.4% 6 0.3% 7 0.3% 8 0.3% 13 0.4% 13 0.6% 8 0.4% 10 0.4%

Sunday Monday

2007-01-01

420

Station # 182 District: 03 Route: SH55 Ascending Direction: North Segment Code and Milepost: 001990 078.864 230 Ft N of Garden Valley Road (N. Banks) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 10 0.3% 6 0.3% 6 0.4% 6 0.4% 7 0.4% 7 0.2% 12 0.3% 6 0.3% 11 0.3%

Sunday Monday

2009-01-01

421

County: Bannock Station # 074 District: 05 Route: US91 Ascending Direction: Northwest Segment Code and Milepost: 002350 041.517 1.0 Miles S.E. of Jct I-15 (Virginia) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 25 1.5% 5 0.3% 8 0.5% 8 0.4% 7 0.4% 15 0.7% 20 1.0% 7 0.4% 22 1.2%

Sunday Monday

2007-01-01

422

Feasibility analysis and residual evaluation of automated planar segmentation results of large-scale Martian surface structures  

NASA Astrophysics Data System (ADS)

As increasingly larger coverage of DTMs is available for the Martian surface, not only the number of studies on individual specific Martian features increase, but the need for large-scale geomorphometric evaluation is amplified as well. The computer power and the increasingly sophisticated methods are about to allow such extensive studies. Our DTM segmentation method that has been tailored and tested recently for various geoscientific applications, now allows to process large DTMs created within the framework of ESA Mars Express HRSC project. The implementation uses computation parallelization, kd-tree approach for storage and several sophisticated techniques in seeking for seed points to improve performance. Test runs on high-capacity multi-core computers demonstrate that now processing of complete DTMs of an orbit is feasible. The possibility to process large areas also implies that the segmentation results in high number of planar facets, typically several thousand features. Furthermore, the segmentation is often sensitive to the initial parameters (number of points to calculate local normal vectors, point-to-plane distance, angular tolerance, etc.) and also the use of splitting segments parameter has typically a stronger influence on the corresponding segmentation pattern. This complexity may complicate the evaluation of the results. In order to recognize the general behaviour a number of test runs have been carried out. The resulting sets of planar facets were then evaluated whether the segmentation fulfilled the original purpose (e.g., in the case of the modeling of an impact crater, its typical features should be modeled. In case of unsatisfying coverage or residual values those models have been sorted out. Model results considered to be satisfying are then analysed from the point of view of the residual values (the pointwise difference of measured height and modeled height). The distributions of the residuals are sometimes asymmetric, but the results are typically still acceptable. Asymmetric and non-continuous segmentations arise if the area is complex, composed of various landforms. This may also imply the need to process the area with various parameter sets, in order to cover features like impact craters, volcanoes, topographic scarps, debris slopes and landslides. According to our experience it is not easy to have low residuals, a good coverage of all features and high percentage of meaningful planar facets. However, this type of result can be achieved by the introduction of successive segmentation phases; the phases process a given number of points and the remaining points will be put into the next segmentation step. The final goal of the whole segmentation is the geostatistical evaluation of the parameters planar features (size, slope, aspect, average of residual values, etc.). This is a co-investigator contribution of the ESA Mars Express High Resolution Stereo Camera research group (principal investigator G. Neukum), and the TMIS.ascrea project has been supported by the Austrian Research Promotion Agency (FFG).

Székely, B.; Dorninger, P.; Koma, Zs.; Jansa, J.; Kovács, G.; Nothegger, C.

2012-04-01

423

Computational fluid dynamics analysis of drag and convective heat transfer of individual body segments for different cyclist positions.  

PubMed

This study aims at investigating drag and convective heat transfer for cyclists at a high spatial resolution. Such an increased spatial resolution, when combined with flow-field data, can increase insight in drag reduction mechanisms and in the thermo-physiological response of cyclists related to heat stress and hygrothermal performance of clothing. Computational fluid dynamics (steady Reynolds-averaged Navier-Stokes) is used to evaluate the drag and convective heat transfer of 19 body segments of a cyclist for three different cyclist positions. The influence of wind speed on the drag is analysed, indicating a pronounced Reynolds number dependency on the drag, where more streamlined positions show a dependency up to higher Reynolds numbers. The drag and convective heat transfer coefficient (CHTC) of the body segments and the entire cyclist are compared for all positions at racing speeds, showing high drag values for the head, legs and arms and high CHTCs for the legs, arms, hands and feet. The drag areas of individual body segments differ markedly for different cyclist positions whereas the convective heat losses of the body segments are found to be less sensitive to the position. CHTC-wind speed correlations are derived, in which the power-law exponent does not differ significantly for the individual body segments for all positions, where an average value of 0.84 is found. Similar CFD studies can be performed to assess drag and CHTCs at a higher spatial resolution for applications in other sport disciplines, bicycle equipment design or to assess convective moisture transfer. PMID:21497817

Defraeye, Thijs; Blocken, Bert; Koninckx, Erwin; Hespel, Peter; Carmeliet, Jan

2011-06-01

424

A hydrogen energy carrier. Volume 2: Systems analysis  

NASA Technical Reports Server (NTRS)

A systems analysis of hydrogen as an energy carrier in the United States indicated that it is feasible to use hydrogen in all energy use areas, except some types of transportation. These use areas are industrial, residential and commercial, and electric power generation. Saturation concept and conservation concept forecasts of future total energy demands were made. Projected costs of producing hydrogen from coal or from nuclear heat combined with thermochemical decomposition of water are in the range $1.00 to $1.50 per million Btu of hydrogen produced. Other methods are estimated to be more costly. The use of hydrogen as a fuel will require the development of large-scale transmission and storage systems. A pipeline system similar to the existing natural gas pipeline system appears practical, if design factors are included to avoid hydrogen environment embrittlement of pipeline metals. Conclusions from the examination of the safety, legal, environmental, economic, political and societal aspects of hydrogen fuel are that a hydrogen energy carrier system would be compatible with American values and the existing energy system.

Savage, R. L. (editor); Blank, L. (editor); Cady, T. (editor); Cox, K. (editor); Murray, R. (editor); Williams, R. D. (editor)

1973-01-01

425

Collinear segment detection using HT neighborhoods.  

PubMed

In this paper, geometrical analysis is used to extract novel straight line segment features from the wings around the peaks of the Hough Transform (HT). Based on these features, a practical segment detection method is proposed which has the ability to determine complete straight line segment parameters including the location of the center, length, slope and the Euclidean distance to the origin. The proposed method does not rely on edge point verification in the image space, i.e., the complete set of segment features are determined only using the information embodied in the HT data. The proposed method can distinguish between highly collinear straight line segments. Segment detection is robust to disturbing edge points, especially ones collinear with the object. A predefined collinear segment resolution that provides a theoretical criterion to determine straight line contiguity is derived. Image processing and analysis experiments show consistent robust performance. PMID:21606034

Du, Shengzhi; Tu, Chunling; van Wyk, Barend Jacobus; Chen, Zengqiang

2011-12-01

426

Small-Volume Analysis of Cell–Cell Signaling Molecules in the Brain  

PubMed Central

Modern science is characterized by integration and synergy between research fields. Accordingly, as technological advances allow new and more ambitious quests in scientific inquiry, numerous analytical and engineering techniques have become useful tools in biological research. The focus of this review is on cutting edge technologies that aid direct measurement of bioactive compounds in the nervous system to facilitate fundamental research, diagnostics, and drug discovery. We discuss challenges associated with measurement of cell-to-cell signaling molecules in the nervous system, and advocate for a decrease of sample volumes to the nanoliter volume regimen for improved analysis outcomes. We highlight effective approaches for the collection, separation, and detection of such small-volume samples, present strategies for targeted and discovery-oriented research, and describe the required technology advances that will empower future translational science. PMID:23748227

Romanova, Elena V; Aerts, Jordan T; Croushore, Callie A; Sweedler, Jonathan V

2014-01-01

427

Variational approach to image segmentation  

NASA Astrophysics Data System (ADS)

This paper deals with a class of variational problems rising from image segmentation. After introducing the mathematical model of this question, we analysis it's rationality in details. At the same time, two numerical methods will be proposed to solve it. Furthermore, the equivalence of these two equations will be proved briefly. At last, we shall apply this result to approximate a minimum problem that was introduced by D.Mumford and J.Shah to Study image Segmentation.

Tian, Yan; Xu, Hongbo; Liu, Jianguo

2001-09-01