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1

PET functional volume segmentation: a robustness study  

Microsoft Academic Search

Current state of the art algorithms for functional volume segmentation in PET images for diagnosis, patients follow-up or radiotherapy treatment planning consist of adaptive threshold approaches. We have developed an unsupervised Bayesian segmentation algorithm for tumors in PET, namely the FLAB (for Fuzzy Locally Adaptive Bayesian) algorithm, that was previously validated on simulated images and then successfully extended and applied

M. Hatt; P. Bailly; A. Turzo; C. Roux; D. Visvikis

2008-01-01

2

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

3

Parallel Mean Shift for Interactive Volume Segmentation  

NASA Astrophysics Data System (ADS)

In this paper we present a parallel dynamic mean shift algorithm based on path transmission for medical volume data segmentation. The algorithm first translates the volume data into a joint position-color feature space subdivided uniformly by bandwidths, and then clusters points in feature space in parallel by iteratively finding its peak point. Over iterations it improves the convergent rate by dynamically updating data points via path transmission and reduces the amount of data points by collapsing overlapping points into one point. The GPU implementation of the algorithm can segment 256x256x256 volume in 6 seconds using an NVIDIA GeForce 8800 GTX card for interactive processing, which is hundreds times faster than its CPU implementation. We also introduce an interactive interface to segment volume data based on this GPU implementation. This interface not only provides the user with the capability to specify segmentation resolution, but also allows the user to operate on the segmented tissues and create desired visualization results.

Zhou, Fangfang; Zhao, Ying; Ma, Kwan-Liu

4

Segmentation-based partial volume correction for volume estimation of solid lesions in CT.  

PubMed

In oncological chemotherapy monitoring, the change of a tumor's size is an important criterion for assessing cancer therapeutics. Measuring the volume of a tumor requires its delineation in 3-D. This is called segmentation, which is an intensively studied problem in medical image processing. However, simply counting the voxels within a binary segmentation result can lead to significant differences in the volume, if the lesion has been segmented slightly differently by various segmentation procedures or in different scans, for example due to the limited spatial resolution of computed tomography (CT) or partial volume effects. This variability limits the sensitivity of size measurements and thus of therapy response assessments and it can even lead to misclassifications. We present a fast, generic algorithm for measuring the volume of solid, compact tumors in CT that considers partial volume effects at the border of a given segmentation result. The algorithm is an extension of the segmentation-based partial volume analysis proposed by Kuhnigk for the volumetry of solid lung lesions , such that it can be applied to inhomogeneous lesions and lesions with inhomogeneous surroundings. Our generalized segmentation-based partial volume correction is based on a spatial subdivision of the segmentation result, from which the fraction of tumor for each voxel is computed. It has been evaluated on phantom data, 1516 lesion segmentation pairs (lung nodules, liver metastases and lymph nodes) as well as 1851 lung nodules from the LIDC-IDRI database. The evaluations of our algorithm show a more accurate estimation of the real volume and its ability to reduce inter- and intra-observer variability significantly for each entity. Overall, the variability (interquartile range) for phantom data is reduced by 49% ( p ? 0.001) and the variability between different readers is reduced by 28% ( p ? 0.001). The average computation time is 0.2 s. PMID:24184707

Heckel, Frank; Meine, Hans; Moltz, Jan H; Kuhnigk, Jan-Martin; Heverhagen, Johannes T; Kiessling, Andreas; Buerke, Boris; Hahn, Horst K

2014-02-01

5

Assessment of Left Ventricular Function by Analysis of Volume-Time Curves of 16 Segments with Real-Time Three Dimensional Echocardiography: Left Ventricular Asynchrony as a Clinical Parameter for Patients with Heart Failure  

Microsoft Academic Search

Background and Objectives:Recent technical developments with high-resolution real-time 3-dimensional echo- cardiography (RT3DE) have facilitated the acquisition of high quality images and the analysis of segmental volume- time curves (VTCs). The purposes of this study were to assess left ventricular (LV) asynchrony with using the VTCs of 16 segments by RT3DE and to compare this with tissue Doppler imaging (TDI) as

Seong-Mi Park; Gi-Chang Kim; Min-Jae Jeon; Chang-Kun Lee; Dae-Hyeok Kim; Keum-Soo Park; Woo-Hyung Lee; Jun Kwan

2006-01-01

6

To be presented at the IEEE VR 2013 Workshop on Interactive Volume Interaction, March 2013 at Orlando, FL Interactive Coarse Segmentation and Analysis of Volume Data with a  

E-print Network

to evaluate these different 3D interaction tools for the various tasks performed by scientists for analyzing Tools Bireswar Laha* and Doug A. Bowman* ABSTRACT Manual and automatic segmentation of raw volumetric a suite of 3D interaction tools for interactive coarse segmentation of raw volumetric datasets, aimed

7

Segment-specific resistivity improves body fluid volume estimates from bioimpedance spectroscopy in hemodialysis patients.  

PubMed

Discrepancies in body fluid estimates between segmental bioimpedance spectroscopy (SBIS) and gold-standard methods may be due to the use of a uniform value of tissue resistivity to compute extracellular fluid volume (ECV) and intracellular fluid volume (ICV). Discrepancies may also arise from the exclusion of fluid volumes of hands, feet, neck, and head from measurements due to electrode positions. The aim of this study was to define the specific resistivity of various body segments and to use those values for computation of ECV and ICV along with a correction for unmeasured fluid volumes. Twenty-nine maintenance hemodialysis patients (16 men) underwent body composition analysis including whole body MRI, whole body potassium (40K) content, deuterium, and sodium bromide dilution, and segmental and wrist-to-ankle bioimpedance spectroscopy, all performed on the same day before a hemodialysis. Segment-specific resistivity was determined from segmental fat-free mass (FFM; by MRI), hydration status of FFM (by deuterium and sodium bromide), tissue resistance (by SBIS), and segment length. Segmental FFM was higher and extracellular hydration of FFM was lower in men compared with women. Segment-specific resistivity values for arm, trunk, and leg all differed from the uniform resistivity used in traditional SBIS algorithms. Estimates for whole body ECV, ICV, and total body water from SBIS using segmental instead of uniform resistivity values and after adjustment for unmeasured fluid volumes of the body did not differ significantly from gold-standard measures. The uniform tissue resistivity values used in traditional SBIS algorithms result in underestimation of ECV, ICV, and total body water. Use of segmental resistivity values combined with adjustment for body volumes that are neglected by traditional SBIS technique significantly improves estimations of body fluid volume in hemodialysis patients. PMID:16254072

Zhu, F; Kuhlmann, M K; Kaysen, G A; Sarkar, S; Kaitwatcharachai, C; Khilnani, R; Stevens, L; Leonard, E F; Wang, J; Heymsfield, S; Levin, N W

2006-02-01

8

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

9

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

PubMed Central

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

2014-01-01

10

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

11

Fast and Automatic Segmentation of Ascending Aorta in MSCT Volume Data  

Microsoft Academic Search

The segmentation of the ascending aorta from multislice computed tomography (MSCT) volume data is one of the critical steps for the quantitative analysis coronary artery. In this paper, a fast and automatic iterative method is presented. The method locates the volume of interest (VOI) of the ascending aorta and detects the seed point automatically. Then an automatic iterative procedure is

Shengjun Wang; Ling Fu; Yong Yue; Yan Kang; Jiren Liu

2009-01-01

12

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. PMID:25599044

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

2014-01-01

13

Carving: Scalable Interactive Segmentation of Neural Volume Electron Microscopy Images  

E-print Network

Carving: Scalable Interactive Segmentation of Neural Volume Electron Microscopy Images C. N electron microscopy images. We propose a supervoxel-based en- ergy function with a novel background prior that achieves these goals. This is verified by extensive experiments with a robot mimicking human interactions

Hamprecht, Fred A.

14

Segmentation Methods For Automatic Kidney Volume Quantification In Spect  

Microsoft Academic Search

Our aim is to develop an objective and reproducible kidney volume estimation using SPECT for 9gm Tc-OMSA renal imaging. For this, the major problem stems from the delineation of kidney b orders. Therefore, we used and compared three methods of segmentation : with fixed threshold, g ray level histogram and mathematical morphology technics. The first method applied to a series

J.-Y. Boire; J.-C. Cauvin; P. Cluzel; M. Lahellec; J. Maublant; M. Zanca; A. Veyre

1990-01-01

15

Segmental approach to lung volume reduction therapy for emphysema patients.  

PubMed

Emphysema is often distributed heterogeneously throughout the lungs, even at the segmental level. It is important for interventional lung volume reduction therapies to target and treat the most diseased regions of the lung while preserving the less diseased functional regions. Identification and determination of the severity of emphysema can be done using the various quantification measures reviewed in this article. However, all of these measures are similar in what they quantify and are equally good indicators of emphysema. The tissue/air ratio was chosen for our purposes. Software capable of quantifying emphysema severity at the segmental level exists, and can be utilized to identify the most diseased segments while following anatomical boundaries. The segmental heterogeneity index is a new measure being introduced to help quantify differences in emphysema severity at the segmental level. The goal of segmental targeting is to improve efficacy and safety outcomes of vapor ablation patients. The Sequential Staged Treatment of Emphysema with Upper Lobe Predominance (STEP-UP, NCT01719263) trial is currently enrolling patients with upper lobe heterogeneous emphysema using these techniques. PMID:25500669

Bandyopadhyay, Sourish; Henne, Erik; Gupta, Avina; Barry, Robert; Snell, Greg; Strange, Charlie; Herth, Felix J F

2015-01-01

16

A segmental analysis of the beetle antenna  

Microsoft Academic Search

SUMMARY - A segmental analysis of the beetle antenna - Number of antennal articles in adult and larval Coleoptera is surveyed. Eleven articles must be credited to the ground-plan of the adult beetle antenna, and three, or possibly four, to the larval one. A new model is presented, aiming at explaining, in terms of segmentation process, the origin of the

Alessandro MINELLI

17

Force Analysis for Segmental Grinding  

E-print Network

) Better lubrication 4) Segmental grinding #12;Force Modeling Fz = Fzc + Fz0 Fx = Fxc + Fx0 Fz Fx total/s Grinding wheel (Alum. Oxide) Workpiece (4140 Steel) Dynamometer Amplifier z x t Fz Fx t F=k(MRR)m+F0 #12;F 60 90 120 0 30 60 90 120 d (µm) Fz(N) v=45 mm/s v=82 mm/s v=114 mm/s v=150 mm/s #12;0 20 40 60 80 100

Endres. William J.

18

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

19

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

20

Fuzzy hidden Markov chains segmentation for volume determination and quantitation in PET.  

PubMed

Accurate volume of interest (VOI) estimation in PET is crucial in different oncology applications such as response to therapy evaluation and radiotherapy treatment planning. The objective of our study was to evaluate the performance of the proposed algorithm for automatic lesion volume delineation; namely the fuzzy hidden Markov chains (FHMC), with that of current state of the art in clinical practice threshold based techniques. As the classical hidden Markov chain (HMC) algorithm, FHMC takes into account noise, voxel intensity and spatial correlation, in order to classify a voxel as background or functional VOI. However the novelty of the fuzzy model consists of the inclusion of an estimation of imprecision, which should subsequently lead to a better modelling of the 'fuzzy' nature of the object of interest boundaries in emission tomography data. The performance of the algorithms has been assessed on both simulated and acquired datasets of the IEC phantom, covering a large range of spherical lesion sizes (from 10 to 37 mm), contrast ratios (4:1 and 8:1) and image noise levels. Both lesion activity recovery and VOI determination tasks were assessed in reconstructed images using two different voxel sizes (8 mm3 and 64 mm3). In order to account for both the functional volume location and its size, the concept of % classification errors was introduced in the evaluation of volume segmentation using the simulated datasets. Results reveal that FHMC performs substantially better than the threshold based methodology for functional volume determination or activity concentration recovery considering a contrast ratio of 4:1 and lesion sizes of <28 mm. Furthermore differences between classification and volume estimation errors evaluated were smaller for the segmented volumes provided by the FHMC algorithm. Finally, the performance of the automatic algorithms was less susceptible to image noise levels in comparison to the threshold based techniques. The analysis of both simulated and acquired datasets led to similar results and conclusions as far as the performance of segmentation algorithms under evaluation is concerned. PMID:17664555

Hatt, M; Lamare, F; Boussion, N; Turzo, A; Collet, C; Salzenstein, F; Roux, C; Jarritt, P; Carson, K; Cheze-Le Rest, C; Visvikis, D

2007-06-21

21

Automatic segmentation of the coronary artery in MSCT volume data  

Microsoft Academic Search

Extracting coronary artery is one of the vital steps in the analysis process based on the modality of computed tomography angiography (CTA), the aim of which is to recognize coronary artery from 3D volume data, and then provide evidences of analysis and quantitative measurement information for coronary artery computer aided detection. According to the structure features of coronary artery angiography

Shengjun Wang; Ling Fu; Yong Yue; Yan Kang; Jiren Liu

2009-01-01

22

Using Segment Congruence Analysis to Determine Actionability of Travel\\/Tourism Segments  

Microsoft Academic Search

We introduced in this paper an analytic technique to help the travel\\/tourism marketer determine the actionability of viable or potential tourist segments. This technique is referred to as segment congruence analysis. The study was conducted using Maine as a tourist destination. Subjects were segmented based on psychographics, tourism-specific life-style variables, and tourism-specific benefit variables. Segment congruence analysis showed that the

J. S. Johar; M Joseph Sirgy

1996-01-01

23

Contour Segment Analysis for Human Silhouette Pre-segmentation  

E-print Network

for the shortest-path cycle in a graph. Here, contour segments are an interesting support. Given that only shape detection windows. SVM [15], Fig. 2. The "descriptor/classifier" framework principle (a) and image

Paris-Sud XI, Université de

24

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

25

Spinal Cord Segmentation for Volume Estimation in Healthy and Multiple Sclerosis Subjects using Crawlers and Minimal Paths  

E-print Network

Spinal Cord Segmentation for Volume Estimation in Healthy and Multiple Sclerosis Subjects using Columbia Vancouver, Canada roger.tam@ubc.ca Abstract--Spinal cord analysis is an important problem of both healthy and pathological spinal cords from clinical MR data. This is the first study to validate

Hamarneh, Ghassan

26

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

27

Estimating Untracked Gaming Volumes by Hotel Occupancy Segment  

Microsoft Academic Search

Many Las Vegas gaming properties also operate hotels with thousands of rooms, which cannot be filled with premium gamblers every night. Given the fierce competition for premium gamblers, hotel-casino executives must pursue other segments as well. To choose segments that optimize earnings, management must compute the total value of a room night for each target segment. Customer spending traverses several

Anthony F. Lucas

2011-01-01

28

Fuzzy hidden Markov chains segmentation for volume determination and quantitation in PET  

PubMed Central

Accurate volume of interest (VOI) estimation in PET is crucial in different oncology applications such as response to therapy evaluation and radiotherapy treatment planning. The objective of our study was to evaluate the performance of the proposed algorithm for automatic lesion volume delineation; namely the Fuzzy Hidden Markov Chains (FHMC), with that of current state of the art in clinical practice threshold based techniques. As the classical Hidden Markov Chain (HMC) algorithm, FHMC takes into account noise, voxel’s intensity and spatial correlation, in order to classify a voxel as background or functional VOI. However the novelty of the fuzzy model consists of the inclusion of an estimation of imprecision, which should subsequently lead to a better modelling of the “fuzzy” nature of the object on interest boundaries in emission tomography data. The performance of the algorithms has been assessed on both simulated and acquired datasets of the IEC phantom, covering a large range of spherical lesion sizes (from 10 to 37mm), contrast ratios (4:1 and 8:1) and image noise levels. Both lesion activity recovery and VOI determination tasks were assessed in reconstructed images using two different voxel sizes (8mm3 and 64mm3). In order to account for both the functional volume location and its size, the concept of % classification errors was introduced in the evaluation of volume segmentation using the simulated datasets. Results reveal that FHMC performs substantially better than the threshold based methodology for functional volume determination or activity concentration recovery considering a contrast ratio of 4:1 and lesion sizes of <28mm. Furthermore differences between classification and volume estimation errors evaluated were smaller for the segmented volumes provided by the FHMC algorithm. Finally, the performance of the automatic algorithms was less susceptible to image noise levels in comparison to the threshold based techniques. The analysis of both simulated and acquired datasets led to similar results and conclusions as far as the performance of segmentation algorithms under evaluation is concerned. PMID:17664555

Hatt, Mathieu; Lamare, Frédéric; Boussion, Nicolas; Roux, Christian; Turzo, Alexandre; Cheze-Lerest, Catherine; Jarritt, Peter; Carson, Kathryn; Salzenstein, Fabien; Collet, Christophe; Visvikis, Dimitris

2007-01-01

29

A Unifying Framework for Inhomogeneity Correction and Partial Volume Segmentation of Brain MR Images  

E-print Network

and partial volume (PV) segmentation of multi-spectral brain magnetic resonance (MR) images. The MR data by the National Institutes of Health (grant #CA82402), the National Multiple Sclerosis Society (grant #RG3042-A-2

30

[Segment analysis of the target market of physiotherapeutic services].  

PubMed

The objective of the present study was to demonstrate the possibilities to analyse selected segments of the target market of physiotherapeutic services provided by medical and preventive-facilities of two major types. The main features of a target segment, such as provision of therapeutic massage, are illustrated in terms of two characteristics, namely attractiveness to the users and the ability of a given medical facility to satisfy their requirements. Based on the analysis of portfolio of the available target segments the most promising ones (winner segments) were selected for further marketing studies. This choice does not exclude the possibility of involvement of other segments of medical services in marketing activities. PMID:21332088

Babaskin, D V

2010-01-01

31

Fuzzy hidden Markov chains segmentation for volume determination and quantitation in PET  

E-print Network

1 Fuzzy hidden Markov chains segmentation for volume determination and quantitation in PET M. Hatt1;52(12):3467-91" DOI : 10.1088/0031-9155/52/12/010 #12;2 ABSTRACT Accurate volume of interest (VOI) estimation in PET is concerned. inserm-00150348,version1-6Apr2009 #12;3 1. Introduction Positron Emission Tomography (PET) has

Paris-Sud XI, Université de

32

Estimation of Tumor Volume with Fuzzy Connectedness Segmentation of MR Images  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Reproducible measurements of brain tumor volume are helpful in evaluating the response to therapy and the need for changing treatment plans. Our purpose was to adapt the fuzzy-connectedness segmentation technique to measure tumor volume. This technique requires only limited operator interaction. METHODS: Routine postoperative brain MR imaging was performed in 19 patients with primary malignant gliomas of

Gul Moonis; Jianguo Liu; Jayaram K. Udupa; David B. Hackney

2002-01-01

33

A Linear Program Formulation for the Segmentation of Ciona Membrane Volumes  

PubMed Central

We address the problem of cell segmentation in confocal microscopy membrane volumes of the ascidian Ciona used in the study of morphogenesis. The primary challenges are non-uniform and patchy membrane staining and faint spurious boundaries from other organelles (e.g. nuclei). Traditional segmentation methods incorrectly attach to faint boundaries producing spurious edges. To address this problem, we propose a linear optimization framework for the joint correction of multiple over-segmentations obtained from different methods. The main idea motivating this approach is that multiple over-segmentations, resulting from a pool of methods with various parameters, are likely to agree on the correct segment boundaries, while spurious boundaries are method- or parameter-dependent. The challenge is to make an optimized decision on selecting the correct boundaries while discarding the spurious ones. The proposed unsupervised method achieves better performance than state of the art methods for cell segmentation from membrane images. PMID:24505697

Delibaltov, Diana L.; Ghosh, Pratim; Rodoplu, Volkan; Veeman, Michael; Smith, William; Manjunath, B.S.

2014-01-01

34

Spinal Crawlers: Deformable Organisms for Spinal Cord Segmentation and Analysis  

E-print Network

Spinal Crawlers: Deformable Organisms for Spinal Cord Segmentation and Analysis Chris Mc, Canada {cmcintos, hamarneh}@cs.sfu.ca Abstract. Spinal cord analysis is an important problem relating to the study of various neurological diseases. We present a novel approach to spinal cord segmentation

Hamarneh, Ghassan

35

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

36

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

37

Vessel segmentation for angiographic enhancement and analysis  

E-print Network

. Proliferative diabetic retinopathy is characterized by neovascular- ization (the growth of new blood vessels retinopathy). In this paper we describe algorithms for automatic vessel segmentation in angiograms. We first

Lübeck, Universität zu

38

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

39

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

40

Automated segmentation of mesothelioma volume on CT scan  

NASA Astrophysics Data System (ADS)

In mesothelioma, response is usually assessed by computed tomography (CT). In current clinical practice the Response Evaluation Criteria in Solid Tumors (RECIST) or WHO, i.e., the uni-dimensional or the bi-dimensional measurements, is applied to the assessment of therapy response. However, the shape of the mesothelioma volume is very irregular and its longest dimension is almost never in the axial plane. Furthermore, the sections and the sites where radiologists measure the tumor are rather subjective, resulting in poor reproducibility of tumor size measurements. We are developing an objective three-dimensional (3D) computer algorithm to automatically identify and quantify tumor volumes that are associated with malignant pleural mesothelioma to assess therapy response. The algorithm first extracts the lung pleural surface from the volumetric CT images by interpolating the chest ribs over a number of adjacent slices and then forming a volume that includes the thorax. This volume allows a separation of mesothelioma from the chest wall. Subsequently, the structures inside the extracted pleural lung surface, including the mediastinal area, lung parenchyma, and pleural mesothelioma, can be identified using a multiple thresholding technique and morphological operations. Preliminary results have shown the potential of utilizing this algorithm to automatically detect and quantify tumor volumes on CT scans and thus to assess therapy response for malignant pleural mesothelioma.

Zhao, Binsheng; Schwartz, Lawrence; Flores, Raja; Liu, Fan; Kijewski, Peter; Krug, Lee; Rusch, Valerie

2005-04-01

41

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

42

Similarity enhancement for automatic segmentation of cardiac structures in computed tomography volumes.  

PubMed

The aim of this research is proposing a 3-D similarity enhancement technique useful for improving the segmentation of cardiac structures in Multi-Slice Computerized Tomography (MSCT) volumes. The similarity enhancement is obtained by subtracting the intensity of the current voxel and the gray levels of their adjacent voxels in two volumes resulting after preprocessing. Such volumes are: a. - a volume obtained after applying a Gaussian distribution and a morphological top-hat filter to the input and b. - a smoothed volume generated by processing the input with an average filter. Then, the similarity volume is used as input to a region growing algorithm. This algorithm is applied to extract the shape of cardiac structures, such as left and right ventricles, in MSCT volumes. Qualitative and quantitative results show the good performance of the proposed approach for discrimination of cardiac cavities. PMID:22256220

Vera, Miguel; Bravo, Antonio; Garreau, Mireille; Medina, Rubén

2011-01-01

43

Similarity enhancement for automatic segmentation of cardiac structures in computed tomography volumes  

PubMed Central

The aim of this research is proposing a 3–D similarity enhancement technique useful for improving the segmentation of cardiac structures in Multi-Slice Computerized Tomography (MSCT) volumes. The similarity enhancement is obtained by subtracting the intensity of the current voxel and the gray levels of their adjacent voxels in two volumes resulting after preprocessing. Such volumes are: a.- a volume obtained after applying a Gaussian distribution and a morphological top-hat filter to the input and b.- a smoothed volume generated by processing the input with an average filter. Then, the similarity volume is used as input to a region growing algorithm. This algorithm is applied to extract the shape of cardiac structures, such as left and right ventricles, in MSCT volumes. Qualitative and quantitative results show the good performance of the proposed approach for discrimination of cardiac cavities. PMID:22256220

Vera, Miguel; Bravo, Antonio; Garreau, Mireille; Medina, Rubén

2011-01-01

44

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

45

Video Segmentation Through Multiscale Texture Analysis  

Microsoft Academic Search

Segmenting a video sequence into different coherent scenes requires analyzing those aspects which allow fi nding the changes where a transition is to be found. Textures are an important feature when we try to identify or classify elements in as cene and, therefore, can be very helpful to find those frames where there is a transition. Furthermore, an- alyzing the

Miguel Alemán-flores; Luis Álvarez-león

2004-01-01

46

Toward accurate segmentation of the LV myocardium and chamber for volumes  

E-print Network

extraction from the images. New algo- rithms for segmenting the heart left ventricle myocardium and chamber to the high level of noise and the signal drops resulting of insufficiently perfused regions. The LV chamber for the estimation of the heart wall thickness and the chamber volume variation during the heart cycle

Paris-Sud XI, Université de

47

Segments.  

ERIC Educational Resources Information Center

Presents a market taxonomy for higher education, including what it reveals about the structure of the market, the model's technical attributes, and its capacity to explain pricing behavior. Details the identification of the principle seams separating one market segment from another and how student aspirations help to organize the market, making…

Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

2001-01-01

48

Segmentation Algorithm for Diesel Spray Image Analysis  

NASA Astrophysics Data System (ADS)

An algorithm for segmentation of diesel spray images has been developed. Its most important feature is robustness against experimental setups that fail to guarantee images whose histograms show two distinct peaks. According to the approach presented, only the peak from the background is used, and it is assumed that the background peak is narrow enough not to include too much of the spray. The algorithm has proved successful for evaluation of images from a pressurized vessel as well as from an engine with optical access, with no need for adjusting the tuning parameters. By adjusting them, one may tune the noise sensitivity.

Cronhjort, Andreas; Wåhlin, Fredrik

2004-11-01

49

Segmentation algorithm for diesel spray image analysis.  

PubMed

An algorithm for segmentation of diesel spray images has been developed. Its most important feature is robustness against experimental setups that fail to guarantee images whose histograms show two distinct peaks. According to the approach presented, only the peak from the background is used, and it is assumed that the background peak is narrow enough not to include too much of the spray. The algorithm has proved successful for evaluation of images from a pressurized vessel as well as from an engine with optical access, with no need for adjusting the tuning parameters. By adjusting them, one may tune the noise sensitivity. PMID:15587725

Cronhjort, Andreas; Wåhlin, Fredrik

2004-11-10

50

Automatic segmentation of tumor-laden lung volumes from the LIDC database  

NASA Astrophysics Data System (ADS)

The segmentation of the lung parenchyma is often a critical pre-processing step prior to application of computer-aided detection of lung nodules. Segmentation of the lung volume can dramatically decrease computation time and reduce the number of false positive detections by excluding from consideration extra-pulmonary tissue. However, while many algorithms are capable of adequately segmenting the healthy lung, none have been demonstrated to work reliably well on tumor-laden lungs. Of particular challenge is to preserve tumorous masses attached to the chest wall, mediastinum or major vessels. In this role, lung volume segmentation comprises an important computational step that can adversely affect the performance of the overall CAD algorithm. An automated lung volume segmentation algorithm has been developed with the goals to maximally exclude extra-pulmonary tissue while retaining all true nodules. The algorithm comprises a series of tasks including intensity thresholding, 2-D and 3-D morphological operations, 2-D and 3-D floodfilling, and snake-based clipping of nodules attached to the chest wall. It features the ability to (1) exclude trachea and bowels, (2) snip large attached nodules using snakes, (3) snip small attached nodules using dilation, (4) preserve large masses fully internal to lung volume, (5) account for basal aspects of the lung where in a 2-D slice the lower sections appear to be disconnected from main lung, and (6) achieve separation of the right and left hemi-lungs. The algorithm was developed and trained to on the first 100 datasets of the LIDC image database.

O'Dell, Walter G.

2012-03-01

51

AMASS: Algorithm for MSI Analysis by Semi-supervised Segmentation  

PubMed Central

Mass Spectrometric Imaging (MSI) is a molecular imaging technique that allows the generation of 2D ion density maps for a large complement of the active molecules present in cells and sectioned tissues. Automatic segmentation of such maps according to patterns of co-expression of individual molecules can be used for discovery of novel molecular signatures (molecules that are specifically expressed in particular spatial regions). However, current segmentation techniques are biased towards the discovery of higher abundance molecules and large segments; they allow limited opportunity for user interaction and validation is usually performed by similarity to known anatomical features. We describe here a novel method, AMASS (Algorithm for MSI Analysis by Semi-supervised Segmentation). AMASS relies on the discriminating power of a molecular signal instead of its intensity as a key feature, uses an internal consistency measure for validation, and allows significant user interaction and supervision as options. An automated segmentation of entire leech embryo data images resulted in segmentation domains congruent with many known organs, including heart, CNS ganglia, nephridia, nephridiopores, and lateral and ventral regions, each with a distinct molecular signature. Likewise, segmentation of a rat brain MSI slice data set yielded known brain features, and provided interesting examples of co-expression between distinct brain regions. AMASS represents a new approach for the discovery of peptide masses with distinct spatial features of expression. PMID:21800894

Bruand, Jocelyne; Alexandrov, Theodore; Sistla, Srinivas; Wisztorski, Maxence; Meriaux, Céline; Becker, Michael; Salzet, Michel; Fournier, Isabelle; Macagno, Eduardo; Bafna, Vineet

2011-01-01

52

AMASS: algorithm for MSI analysis by semi-supervised segmentation.  

PubMed

Mass Spectrometric Imaging (MSI) is a molecular imaging technique that allows the generation of 2D ion density maps for a large complement of the active molecules present in cells and sectioned tissues. Automatic segmentation of such maps according to patterns of co-expression of individual molecules can be used for discovery of novel molecular signatures (molecules that are specifically expressed in particular spatial regions). However, current segmentation techniques are biased toward the discovery of higher abundance molecules and large segments; they allow limited opportunity for user interaction, and validation is usually performed by similarity to known anatomical features. We describe here a novel method, AMASS (Algorithm for MSI Analysis by Semi-supervised Segmentation). AMASS relies on the discriminating power of a molecular signal instead of its intensity as a key feature, uses an internal consistency measure for validation, and allows significant user interaction and supervision as options. An automated segmentation of entire leech embryo data images resulted in segmentation domains congruent with many known organs, including heart, CNS ganglia, nephridia, nephridiopores, and lateral and ventral regions, each with a distinct molecular signature. Likewise, segmentation of a rat brain MSI slice data set yielded known brain features and provided interesting examples of co-expression between distinct brain regions. AMASS represents a new approach for the discovery of peptide masses with distinct spatial features of expression. Software source code and installation and usage guide are available at http://bix.ucsd.edu/AMASS/ . PMID:21800894

Bruand, Jocelyne; Alexandrov, Theodore; Sistla, Srinivas; Wisztorski, Maxence; Meriaux, Céline; Becker, Michael; Salzet, Michel; Fournier, Isabelle; Macagno, Eduardo; Bafna, Vineet

2011-10-01

53

Skin segmentation using color pixel classification: analysis and comparison.  

PubMed

This paper presents a study of three important issues of the color pixel classification approach to skin segmentation: color representation, color quantization, and classification algorithm. Our analysis of several representative color spaces using the Bayesian classifier with the histogram technique shows that skin segmentation based on color pixel classification is largely unaffected by the choice of the color space. However, segmentation performance degrades when only chrominance channels are used in classification. Furthermore, we find that color quantization can be as low as 64 bins per channel, although higher histogram sizes give better segmentation performance. The Bayesian classifier with the histogram technique and the multilayer perceptron classifier are found to perform better compared to other tested classifiers, including three piecewise linear classifiers, three unimodal Gaussian classifiers, and a Gaussian mixture classifier. PMID:15628277

Phung, Son Lam; Bouzerdoum, Abdesselam; Chai, Douglas

2005-01-01

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

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

56

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

57

Segment clustering methodology for unsupervised Holter recordings analysis  

NASA Astrophysics Data System (ADS)

Cardiac arrhythmia analysis on Holter recordings is an important issue in clinical settings, however such issue implicitly involves attending other problems related to the large amount of unlabelled data which means a high computational cost. In this work an unsupervised methodology based in a segment framework is presented, which consists of dividing the raw data into a balanced number of segments in order to identify fiducial points, characterize and cluster the heartbeats in each segment separately. The resulting clusters are merged or split according to an assumed criterion of homogeneity. This framework compensates the high computational cost employed in Holter analysis, being possible its implementation for further real time applications. The performance of the method is measure over the records from the MIT/BIH arrhythmia database and achieves high values of sensibility and specificity, taking advantage of database labels, for a broad kind of heartbeats types recommended by the AAMI.

Rodríguez-Sotelo, Jose Luis; Peluffo-Ordoñez, Diego; Castellanos Dominguez, German

2015-01-01

58

A fuzzy locally adaptive Bayesian segmentation approach for volume determination in PET.  

PubMed

Accurate volume estimation in positron emission tomography (PET) is crucial for different oncology applications. The objective of our study was to develop a new fuzzy locally adaptive Bayesian (FLAB) segmentation for automatic lesion volume delineation. FLAB was compared with a threshold approach as well as the previously proposed fuzzy hidden Markov chains (FHMC) and the fuzzy C-Means (FCM) algorithms. The performance of the algorithms was assessed on acquired datasets of the IEC phantom, covering a range of spherical lesion sizes (10-37 mm), contrast ratios (4:1 and 8:1), noise levels (1, 2, and 5 min acquisitions), and voxel sizes (8 and 64 mm(3)). In addition, the performance of the FLAB model was assessed on realistic nonuniform and nonspherical volumes simulated from patient lesions. Results show that FLAB performs better than the other methodologies, particularly for smaller objects. The volume error was 5%-15% for the different sphere sizes (down to 13 mm), contrast and image qualities considered, with a high reproducibility (variation < 4%). By comparison, the thresholding results were greatly dependent on image contrast and noise, whereas FCM results were less dependent on noise but consistently failed to segment lesions < 2 cm. In addition, FLAB performed consistently better for lesions < 2 cm in comparison to the FHMC algorithm. Finally the FLAB model provided errors less than 10% for nonspherical lesions with inhomogeneous activity distributions. Future developments will concentrate on an extension of FLAB in order to allow the segmentation of separate activity distribution regions within the same functional volume as well as a robustness study with respect to different scanners and reconstruction algorithms. PMID:19150782

Hatt, Mathieu; Cheze le Rest, Catherine; Turzo, Alexandre; Roux, Christian; Visvikis, Dimitris

2009-06-01

59

Analysis of recent segmental duplications in the bovine genome  

Technology Transfer Automated Retrieval System (TEKTRAN)

Duplicated sequences are an important source of gene innovation and structural variation within mammalian genomes. We describe the first systematic and genome-wide analysis of segmental duplications in the modern domesticated cattle (Bos taurus). Using two distinct computational analyses, we estimat...

60

A Lifestyle Segmentation Analysis of the Backpacker Market in Scotland  

Microsoft Academic Search

The purpose of the research outlined in this article is to provide a travel lifestyle segmentation analysis of one particular tourist group, commonly known as 'backpackers', who reside in Scottish Youth Hostel Association hostels. This research was undertaken due to the lack of understanding and knowledge of this market in the United Kingdom, specifically their needs, wants and motivations. Five

Maree Thyne; Sylvie Davies; Rob Nash

2005-01-01

61

Segmented Trend Analysis for Stimulus Generalization Studies.  

ERIC Educational Resources Information Center

An analysis of variance model is recommended for data which display a peaked trend. These data are particularly common in psychological studies of stimulus generalization. A variety of hypotheses are suggested, and the testing of these hypotheses is illustrated. (Author/JKS)

Halperin, Silas

1978-01-01

62

Spinal crawlers: Deformable organisms for spinal cord segmentation and analysis  

E-print Network

Abstract. Spinal cord analysis is an important problem relating to the study of various neurological diseases. We present a novel approach to spinal cord segmentation in magnetic resonance images. Our method uses 3D “deformable organisms ” (DefOrg) an artificial life framework for medical image analysis that complements classical deformable models (snakes and deformable meshes) with high-level, anatomically-driven control mechanisms. The DefOrg framework allows us to model the organism’s body as a growing generalized tubular spring-mass system with an adaptive and predominantly elliptical cross section, and to equip them with spinal cord specific sensory modules, behavioral routines and decision making strategies. The result is a new breed of robust DefOrgs, “spinal crawlers”, that crawl along spinal cords in 3D images, accurately segmenting boundaries, and providing sophisticated, clinically-relevant structural analysis. We validate our method through the segmentation of spinal cords in clinical data and provide comparisons to other segmentation techniques. 1

2006-01-01

63

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

64

Semi-automated segmentation of carotid artery total plaque volume from three dimensional ultrasound carotid imaging  

NASA Astrophysics Data System (ADS)

Carotid artery total plaque volume (TPV) is a three-dimensional (3D) ultrasound (US) imaging measurement of carotid atherosclerosis, providing a direct non-invasive and regional estimation of atherosclerotic plaque volume - the direct determinant of carotid stenosis and ischemic stroke. While 3DUS measurements of TPV provide the potential to monitor plaque in individual patients and in populations enrolled in clinical trials, until now, such measurements have been performed manually which is laborious, time-consuming and prone to intra-observer and inter-observer variability. To address this critical translational limitation, here we describe the development and application of a semi-automated 3DUS plaque volume measurement. This semi-automated TPV measurement incorporates three user-selected boundaries in two views of the 3DUS volume to generate a geometric approximation of TPV for each plaque measured. We compared semi-automated repeated measurements to manual segmentation of 22 individual plaques ranging in volume from 2mm3 to 151mm3. Mean plaque volume was 43+/-40mm3 for semi-automated and 48+/-46mm3 for manual measurements and these were not significantly different (p=0.60). Mean coefficient of variation (CV) was 12.0+/-5.1% for the semi-automated measurements.

Buchanan, D.; Gyacskov, I.; Ukwatta, E.; Lindenmaier, T.; Fenster, A.; Parraga, G.

2012-03-01

65

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

66

Can voxel based morphometry, manual segmentation and automated segmentation equally detect hippocampal volume differences in acute depression?  

Microsoft Academic Search

ContextAccording to meta-analyses, depression is associated with a smaller hippocampus. Most magnetic resonance imaging (MRI) studies among middle aged acute depressed patients are based on manual segmentation of the hippocampus. Few studies used automated methods such as voxel-based morphometry (VBM) or automated segmentation that can overcome certain drawbacks of manual segmentation (essentially intra- and inter-rater variability and operator time consumption).

Loretxu Bergouignan; Marie Chupin; Yvonne Czechowska; Serge Kinkingnéhun; Cédric Lemogne; Guillaume Le Bastard; Martin Lepage; Line Garnero; Olivier Colliot; Philippe Fossati

2009-01-01

67

Whole-body and segmental muscle volume are associated with ball velocity in high school baseball pitchers.  

PubMed

The aim of the study was to examine the relationship between pitching ball velocity and segmental (trunk, upper arm, forearm, upper leg, and lower leg) and whole-body muscle volume (MV) in high school baseball pitchers. Forty-seven male high school pitchers (40 right-handers and seven left-handers; age, 16.2 ± 0.7 years; stature, 173.6 ± 4.9 cm; mass, 65.0 ± 6.8 kg, years of baseball experience, 7.5 ± 1.8 years; maximum pitching ball velocity, 119.0 ± 9.0 km/hour) participated in the study. Segmental and whole-body MV were measured using segmental bioelectrical impedance analysis. Maximum ball velocity was measured with a sports radar gun. The MV of the dominant arm was significantly larger than the MV of the non-dominant arm (P < 0.001). There was no difference in MV between the dominant and non-dominant legs. Whole-body MV was significantly correlated with ball velocity (r = 0.412, P < 0.01). Trunk MV was not correlated with ball velocity, but the MV for both lower legs, and the dominant upper leg, upper arm, and forearm were significantly correlated with ball velocity (P < 0.05). The results were not affected by age or years of baseball experience. Whole-body and segmental MV are associated with ball velocity in high school baseball pitchers. However, the contribution of the muscle mass on pitching ball velocity is limited, thus other fundamental factors (ie, pitching skill) are also important. PMID:24379713

Yamada, Yosuke; Yamashita, Daichi; Yamamoto, Shinji; Matsui, Tomoyuki; Seo, Kazuya; Azuma, Yoshikazu; Kida, Yoshikazu; Morihara, Toru; Kimura, Misaka

2013-01-01

68

Whole-body and segmental muscle volume are associated with ball velocity in high school baseball pitchers  

PubMed Central

The aim of the study was to examine the relationship between pitching ball velocity and segmental (trunk, upper arm, forearm, upper leg, and lower leg) and whole-body muscle volume (MV) in high school baseball pitchers. Forty-seven male high school pitchers (40 right-handers and seven left-handers; age, 16.2 ± 0.7 years; stature, 173.6 ± 4.9 cm; mass, 65.0 ± 6.8 kg, years of baseball experience, 7.5 ± 1.8 years; maximum pitching ball velocity, 119.0 ± 9.0 km/hour) participated in the study. Segmental and whole-body MV were measured using segmental bioelectrical impedance analysis. Maximum ball velocity was measured with a sports radar gun. The MV of the dominant arm was significantly larger than the MV of the non-dominant arm (P < 0.001). There was no difference in MV between the dominant and non-dominant legs. Whole-body MV was significantly correlated with ball velocity (r = 0.412, P < 0.01). Trunk MV was not correlated with ball velocity, but the MV for both lower legs, and the dominant upper leg, upper arm, and forearm were significantly correlated with ball velocity (P < 0.05). The results were not affected by age or years of baseball experience. Whole-body and segmental MV are associated with ball velocity in high school baseball pitchers. However, the contribution of the muscle mass on pitching ball velocity is limited, thus other fundamental factors (ie, pitching skill) are also important. PMID:24379713

Yamada, Yosuke; Yamashita, Daichi; Yamamoto, Shinji; Matsui, Tomoyuki; Seo, Kazuya; Azuma, Yoshikazu; Kida, Yoshikazu; Morihara, Toru; Kimura, Misaka

2013-01-01

69

Risk analysis of shield tunnel segment failure based on Fuzzy Fault Tree method  

Microsoft Academic Search

Through analyzing and summarizing the types of shield tunnel segment failure and the relevant causes of the accident, Fuzzy Fault Tree Analysis (FTA) was employed to study the failure risk of segment and the Fuzzy Fault Tree system model of segment and segment-related systems were established. The potential failure modes of risk accidents and their influencing factors were discussed through

Dong-an Zhao; Jun-jie Zheng; Ye-wei Zheng

2010-01-01

70

Automatic segmentation and quantitative analysis of the articular cartilages from magnetic resonance images of the knee.  

PubMed

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

71

Continuous maximum flow segmentation method for nanoparticle interaction analysis.  

PubMed

In recent years, tomographic three-dimensional reconstruction approaches using electrons rather than X-rays have become popular. Such images produced with a transmission electron microscope make it possible to image nanometre-scale materials in three-dimensional. However, they are also noisy, limited in contrast and most often have a very poor resolution along the axis of the electron beam. The analysis of images stemming from such modalities, whether fully or semiautomated, is therefore more complicated. In particular, segmentation of objects is difficult. In this paper, we propose to use the continuous maximum flow segmentation method based on a globally optimal minimal surface model. The use of this fully automated segmentation and filtering procedure is illustrated on two different nanoparticle samples and provide comparisons with other classical segmentation methods. The main objectives are the measurement of the attraction rate of polystyrene beads to silica nanoparticle (for the first sample) and interaction of silica nanoparticles with large unilamellar liposomes (for the second sample). We also illustrate how precise measurements such as contact angles can be performed. PMID:21707616

Marak, L; Tankyevych, O; Talbot, H

2011-10-01

72

Automatic comic page image understanding based on edge segment analysis  

NASA Astrophysics Data System (ADS)

Comic page image understanding aims to analyse the layout of the comic page images by detecting the storyboards and identifying the reading order automatically. It is the key technique to produce the digital comic documents suitable for reading on mobile devices. In this paper, we propose a novel comic page image understanding method based on edge segment analysis. First, we propose an efficient edge point chaining method to extract Canny edge segments (i.e., contiguous chains of Canny edge points) from the input comic page image; second, we propose a top-down scheme to detect line segments within each obtained edge segment; third, we develop a novel method to detect the storyboards by selecting the border lines and further identify the reading order of these storyboards. The proposed method is performed on a data set consisting of 2000 comic page images from ten printed comic series. The experimental results demonstrate that the proposed method achieves satisfactory results on different comics and outperforms the existing methods.

Liu, Dong; Wang, Yongtao; Tang, Zhi; Li, Luyuan; Gao, Liangcai

2013-12-01

73

A Unified Video Segmentation Benchmark: Annotation, Metrics and Analysis Fabio Galasso1  

E-print Network

A Unified Video Segmentation Benchmark: Annotation, Metrics and Analysis Fabio Galasso1 , Naveen segmentation and that is large enough to avoid overfitting. Consequently, there is little analysis of video such an analysis based on annotations of a large video dataset, where each video is manually segmented by multiple

74

Segmented canonical discriminant analysis of in situ hyperspectral data for identifying 13 urban tree species  

Microsoft Academic Search

A total of 458 in situ hyperspectral data were collected from 13 urban tree species in the City of Tampa, FL, USA using a spectrometer. The 13 species include 11 broadleaf and two conifer species. Three different techniques, segmented canonical discriminant analysis (CDA), segmented principal component analysis (PCA) and segmented stepwise discriminate analysis (SDA), were applied and compared for dimension

Ruiliang Pu; Desheng Liu

2011-01-01

75

Automated 3D Segmentation of Multiple Surfaces with a Shared Hole: Segmentation of the Neural Canal Opening in SD-OCT Volumes  

PubMed Central

The need to segment multiple interacting surfaces is a common problem in medical imaging and it is often assumed that such surfaces are continuous within the confines of the region of interest. However, in some application areas, the surfaces of interest may contain a shared hole in which the surfaces no longer exist and the exact location of the hole boundary is not known a priori. The boundary of the neural canal opening seen in spectral-domain optical coherence tomography volumes is an example of a “hole” embedded with multiple surrounding surfaces. Segmentation approaches that rely on finding the surfaces alone are prone to failures as deeper structures within the hole can “attract” the surfaces and pull them away from their correct location at the hole boundary. With this application area in mind, we present a graph-theoretic approach for segmenting multiple surfaces with a shared hole. The overall cost function that is optimized consists of both the costs of the surfaces outside the hole and the cost of boundary of the hole itself. The constraints utilized were appropriately adapted in order to ensure the smoothness of the hole boundary in addition to ensuring the smoothness of the non-overlapping surfaces. By using this approach, a significant improvement was observed over a more traditional two-pass approach in which the surfaces are segmented first (assuming the presence of no hole) followed by segmenting the neural canal opening. PMID:25333185

Antony, Bhavna J.; Miri, Mohammed S.; Abràmoff, Michael D.; Kwon, Young H.; Garvin, Mona K.

2015-01-01

76

Dextrocardia--value of segmental analysis in its categorisation.  

PubMed Central

Dextrocardia can be defined as a heart in the right chest with the major axis to the right. This definition, however, conveys no information regarding the chamber arrangements and internal anatomy of the heart. Of 40 patients satisfying this definition in the files of the Brompton Hospital, 33 had angiocardiographic data adequate for complete analysis in terms of connections, relations, and morphology of cardiac segments. They form the subject of this report. There were 16 (48%) patients with situs solitus, 11 (33%) with situs inversus, and six (18%) with situs ambiguus. Of the cases of situs ambiguus, four exhibited laevoisomerism and two dextroisomerism. Of the 16 patients with situs solitus, six had two ventricles and 10 had univentricular hearts; two patients had concordant and three discordant ventriculoarterial connections, seven had double outlet ventricle, and four a single outlet heart. Of the 11 patients with situs inversus, nine had two ventricles and two a univentricular heart of right ventricular type; the arterial connection was concordant in two, discordant in two, double outlet in six, and single outlet in one. Of the six patients with situs ambiguus and laevo or dextroisomerism, four had two ventricles, and two univentricular hearts; the arterial connection was concordant in one, double outlet in three, and single outlet in two. Segmental analysis and the use of basic descriptive terms are essential to define the complex anatomy of such hearts. Images PMID:518773

Calcaterra, G; Anderson, R H; Lau, K C; Shinebourne, E A

1979-01-01

77

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 ANALYSIS, DATA MINING AND KNOWLEDGE DISCOVERY James C. Tilton* , Diane J. Cook+ , and Nikhil Ketkar+ * Code of image segmentations. An approach capable of discovering patterns in the segmented image data is needed

Cook, Diane J.

78

3D Volume Segmentation of MRA Data Sets Using Level Sets Aly A. Farag, Ph.D. 1  

E-print Network

3D Volume Segmentation of MRA Data Sets Using Level Sets Aly A. Farag, Ph.D. 1 , Hossam Hassan, M.S. 1 , Robert Falk, M.D.2 and Stephen G. Hushek, Ph.D. 3 1 Computer Vision and Image Processing Laboratory, University of Louisville, Louisville, KY 40292 2 Director, Medical Imaging Division Jewish

Farag, Aly A.

79

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

80

SEMI-AUTOMATIC SEGMENTATION OF THE TONGUE FOR 3D MOTION ANALYSIS WITH DYNAMIC MRI  

PubMed Central

Accurate segmentation is an important preprocessing step for measuring the internal deformation of the tongue during speech and swallowing using 3D dynamic MRI. In an MRI stack, manual segmentation of every 2D slice and time frame is time-consuming due to the large number of volumes captured over the entire task cycle. In this paper, we propose a semi-automatic segmentation workflow for processing 3D dynamic MRI of the tongue. The steps comprise seeding a few slices, seed propagation by deformable registration, random walker segmentation of the temporal stack of images and 3D super-resolution volumes. This method was validated on the tongue of two 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 52 volumes showed an average dice similarity coefficient (DSC) score of 0.9 with reduced segmented volume variability compared to manual segmentations. PMID:24443699

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

2013-01-01

81

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

82

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

83

A New Video Analysis Approach for Coherent Key-frame Extraction and Object Segmentation  

E-print Network

A New Video Analysis Approach for Coherent Key-frame Extraction and Object Segmentation Xiaomu Song Email: {xiaomu.song, guoliang.fan}@okstate.edu Abstract-- We discuss a new video analysis approach for coherent key-frame extraction and object segmentation. As two basic units for content-based video analysis

Fan, Guoliang

84

Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation  

PubMed Central

Purpose We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). Materials and Methods The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. Results VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). Conclusion It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

Kang, Sung-Won; Lee, Woo-Jin; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe

2015-01-01

85

Three dimensional level set based semiautomatic segmentation of atherosclerotic carotid artery wall volume using 3D ultrasound imaging  

NASA Astrophysics Data System (ADS)

3D segmentation of carotid plaque from ultrasound (US) images is challenging due to image artifacts and poor boundary definition. Semiautomatic segmentation algorithms for calculating vessel wall volume (VWV) have been proposed for the common carotid artery (CCA) but they have not been applied on plaques in the internal carotid artery (ICA). In this work, we describe a 3D segmentation algorithm that is robust to shadowing and missing boundaries. Our algorithm uses distance regularized level set method with edge and region based energy to segment the adventitial wall boundary (AWB) and lumen-intima boundary (LIB) of plaques in the CCA, ICA and external carotid artery (ECA). The algorithm is initialized by manually placing points on the boundary of a subset of transverse slices with an interslice distance of 4mm. We propose a novel user defined stopping surface based energy to prevent leaking of evolving surface across poorly defined boundaries. Validation was performed against manual segmentation using 3D US volumes acquired from five asymptomatic patients with carotid stenosis using a linear 4D probe. A pseudo gold-standard boundary was formed from manual segmentation by three observers. The Dice similarity coefficient (DSC), Hausdor distance (HD) and modified HD (MHD) were used to compare the algorithm results against the pseudo gold-standard on 1205 cross sectional slices of 5 3D US image sets. The algorithm showed good agreement with the pseudo gold standard boundary with mean DSC of 93.3% (AWB) and 89.82% (LIB); mean MHD of 0.34 mm (AWB) and 0.24 mm (LIB); mean HD of 1.27 mm (AWB) and 0.72 mm (LIB). The proposed 3D semiautomatic segmentation is the first step towards full characterization of 3D plaque progression and longitudinal monitoring.

Hossain, Md. Murad; AlMuhanna, Khalid; Zhao, Limin; Lal, Brajesh K.; Sikdar, Siddhartha

2014-03-01

86

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

87

The Analysis of Image Segmentation Hierarchies with a Graph-based Knowledge Discovery System  

NASA Technical Reports Server (NTRS)

Currently available pixel-based analysis techniques do not effectively extract the information content from the increasingly available high spatial resolution remotely sensed imagery data. A general consensus is that object-based image analysis (OBIA) is required to effectively analyze this type of data. OBIA is usually a two-stage process; image segmentation followed by an analysis of the segmented objects. We are exploring an approach to OBIA in which hierarchical image segmentations provided by the Recursive Hierarchical Segmentation (RHSEG) software developed at NASA GSFC are analyzed by the Subdue graph-based knowledge discovery system developed by a team at Washington State University. In this paper we discuss out initial approach to representing the RHSEG-produced hierarchical image segmentations in a graphical form understandable by Subdue, and provide results on real and simulated data. We also discuss planned improvements designed to more effectively and completely convey the hierarchical segmentation information to Subdue and to improve processing efficiency.

Tilton, James C.; Cooke, diane J.; Ketkar, Nikhil; Aksoy, Selim

2008-01-01

88

Unsupervised Segmentation Using Gabor Wavelets and Statistical Features in LIDAR Data Analysis  

E-print Network

filters have been used widely in image texture analysis due to their nature of spatial localityUnsupervised Segmentation Using Gabor Wavelets and Statistical Features in LIDAR Data Analysis Hong information, e.g. houses, vegetation, flat field, river, basin, etc. Our aim in this paper is to segment

Reading, University of

89

Analysis on Market Segmentation and Marketing Strategy of Vegetables Consumption - A Case Study in Changsha  

Microsoft Academic Search

The paper has studied the beneficial segmentation status of vegetable consumption market with the statistical methods of factor analysis and cluster analysis. Its purpose is to promote the development of vegetable industry and its marketing strategy in Hunan province by deeply exploring the purchasing behavior and demography characteristics of vegetables purchasers in different segment market. The results indicate that the

Sun Yan-hua; Zhou Fa-ming; Liu Xiang-hui

2009-01-01

90

Market Segmentation Analysis of Preferences for GM Derived Animal Foods in the UK  

Microsoft Academic Search

This paper undertakes a detailed market segmentation analysis of the demand for GM derived animal foods in the UK with the aim of illustrating how this analysis can provide distinct information that can assists in evaluating the welfare impacts of proposed changes to the EU's GM labelling policy. The specific modelling approach employed was the latent segment (LS) model which

Andreas Kontoleon; Mitsuyasu Yabe

2006-01-01

91

Object Segmentation by Long Term Analysis of Point Trajectories  

E-print Network

results in temporally consistent segmentations of moving objects in a video shot. In contrast to multi-body factorization, points and even whole objects may appear or disappear during the shot. We provide a benchmark necessary? Animals or infants are not supplied bounding boxes or segmented training images when they learn

Kim, Tae-Kyun

92

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

93

Quantitative analysis of the conservation of the tertiary structure of protein segments.  

PubMed

The publication of the crystallographic structure of calmodulin protein has offered an example leading us to believe that it is possible for many protein sequence segments to exhibit multiple 3D structures referred to as multi-structural segments. To this end, this paper presents statistical analysis of uniqueness of the 3D-structure of all possible protein sequence segments stored in the Protein Data Bank (PDB, Jan. of 2003, release 103) that occur at least twice and whose lengths are greater than 10 amino acids (AAs). We refined the set of segments by choosing only those that are not parts of longer segments, which resulted in 9297 segments called a sponge set. By adding 8197 signature segments, which occur uniquely in the PDB, into the sponge set we have generated a benchmark set. Statistical analysis of the sponge set demonstrates that rotating, missing and disarranging operations described in the text, result in the segments becoming multi-structural. It turns out that missing segments do not exhibit a change of shape in the 3D-structure of a multi-structural segment. We use the root mean square distance for unit vector sequence (URMSD) as an improved measure to describe the characteristics of hinge rotations, missing, and disarranging segments. We estimated the rate of occurrence for rotating and disarranging segments in the sponge set and divided it by the number of sequences in the benchmark set which is found to be less than 0.85%. Since two of the structure changing operations concern negligible number of segment and the third one is found not to have impact on the structure, we conclude that the 3D-structure of proteins is conserved statistically for more than 98% of the segments. At the same time, the remaining 2% of the sequences may pose problems for the sequence alignment based structure prediction methods. PMID:16957991

Ruan, Jishou; Chen, Ke; Tuszynski, Jack A; Kurgan, Lukasz A

2006-07-01

94

Improving the clinical correlation of multiple sclerosis black hole volume change by paired-scan analysis.  

PubMed

The change in T 1-hypointense lesion ("black hole") volume is an important marker of pathological progression in multiple sclerosis (MS). Black hole boundaries often have low contrast and are difficult to determine accurately and most (semi-)automated segmentation methods first compute the T 2-hyperintense lesions, which are a superset of the black holes and are typically more distinct, to form a search space for the T 1w lesions. Two main potential sources of measurement noise in longitudinal black hole volume computation are partial volume and variability in the T 2w lesion segmentation. A paired analysis approach is proposed herein that uses registration to equalize partial volume and lesion mask processing to combine T 2w lesion segmentations across time. The scans of 247 MS patients are used to compare a selected black hole computation method with an enhanced version incorporating paired analysis, using rank correlation to a clinical variable (MS functional composite) as the primary outcome measure. The comparison is done at nine different levels of intensity as a previous study suggests that darker black holes may yield stronger correlations. The results demonstrate that paired analysis can strongly improve longitudinal correlation (from -0.148 to -0.303 in this sample) and may produce segmentations that are more sensitive to clinically relevant changes. PMID:24179734

Tam, Roger C; Traboulsee, Anthony; Riddehough, Andrew; Li, David K B

2012-01-01

95

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

96

Recurrence interval analysis of trading volumes.  

PubMed

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. PMID:20866478

Ren, Fei; Zhou, Wei-Xing

2010-06-01

97

Swept Volume Parameterization for Isogeometric Analysis  

Microsoft Academic Search

Isogeometric Analysis uses NURBS representations of the domain for performing numerical simulations. The first part of this\\u000a paper presents a variational framework for generating NURBS parameterizations of swept volumes. The class of these volumes\\u000a covers a number of interesting free-form shapes, such as blades of turbines and propellers, ship hulls or wings of airplanes.\\u000a The second part of the paper

C. Heinrich; Bert Jüttler; Elisabeth Pilgerstorfer; B. Simeon; A. v. Vuong; Martin Aigner

2009-01-01

98

Direct incremental model-based image motion segmentation for video analysis  

Microsoft Academic Search

Dynamic analysis of image sequences is an important task in object-oriented video applications. It often relies on the segmentation of each image of the sequence into region entities of apparent homogeneous motion. In this paper, we present an original motion segmentation algorithm based on 2D polynomial motion models, a multiresolution robust estimator to compute these motion models, and appropriate local

Jean-Marc Odobez; Patrick Bouthemy

1998-01-01

99

Segmentation, Content Extraction and Visualization of Broadcast News Video using Multistream Analysis  

Microsoft Academic Search

This paper reports the development of a broadcast news video corpora and novel techniques to automatically segment stories, extract proper names, and visualize associated metadata. We report story segmentation and proper name extraction results using an information retrieval inspired evaluation methodology, measuring the precision and recall performance of our techniques. We briefly describe our implementation of a Broadcast News Analysis

Mark Maybury; Andrew Merlino; James Rayson

100

ANALYSIS OF GRADIENT FLOW OF A REGULARIZED MUMFORDSHAH FUNCTIONAL FOR IMAGE SEGMENTATION AND IMAGE INPAINTING #  

E-print Network

, and adopted by Esedoglu and Shen [20] for image inpainting. It is shown that the gradient flow with L 2 � L = o(h 1 2 ). Key words. Image segmentation and inpainting, Mumford­Shah model, elliptic approximationANALYSIS OF GRADIENT FLOW OF A REGULARIZED MUMFORD­SHAH FUNCTIONAL FOR IMAGE SEGMENTATION AND IMAGE

101

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

102

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

103

Bayesian Hidden Markov model for DNA Sequence Segmentation : A prior sensitivity analysis  

E-print Network

Bayesian Hidden Markov model for DNA Sequence Segmentation : A prior sensitivity analysis Darfiana in a hidden Markov model describing homogeneous segments of DNA sequences. An intron from the chimpanzee estimates obtained under a Bayesian hidden Markov model are indeed sensitive to the specification

Paris-Sud XI, Université de

104

Quantitative Analysis of Peristaltic and Segmental Motion In Vivo in the Rat Small Intestine Using Dynamic  

E-print Network

Quantitative Analysis of Peristaltic and Segmental Motion In Vivo in the Rat Small Intestine Using of nutrients that takes place within the small intestine. The normal processes of the small intestine are known been used extensively to study segments of the intestine that have been exteriorized from animals

Brasseur, James G.

105

Segmentation-based and rule-based spectral mixture analysis for estimating urban imperviousness  

NASA Astrophysics Data System (ADS)

For detailed estimation of urban imperviousness, numerous image processing methods have been developed, and applied to different urban areas with some success. Most of these methods, however, are global techniques. That is, they have been applied to the entire study area without considering spatial and contextual variations. To address this problem, this paper explores whether two spatio-contextual analysis techniques, namely segmentation-based and rule-based analysis, can improve urban imperviousness estimation. These two spatio-contextual techniques were incorporated to a classic urban imperviousness estimation technique, fully-constrained linear spectral mixture analysis (FCLSMA) method. In particular, image segmentation was applied to divide the image to homogenous segments, and spatially varying endmembers were chosen for each segment. Then an FCLSMA was applied for each segment to estimate the pixel-wise fractional coverage of high-albedo material, low-albedo material, vegetation, and soil. Finally, a rule-based analysis was carried out to estimate the percent impervious surface area (%ISA). The developed technique was applied to a Landsat TM image acquired in Milwaukee River Watershed, an urbanized watershed in Wisconsin, United States. Results indicate that the performance of the developed segmentation-based and rule-based LSMA (S-R-LSMA) outperforms traditional SMA techniques, with a mean average error (MAE) of 5.44% and R2 of 0.88. Further, a comparative analysis shows that, when compared to segmentation, rule-based analysis plays a more essential role in improving the estimation accuracy.

Li, Miao; Zang, Shuying; Wu, Changshan; Deng, Yingbin

2015-03-01

106

Structured Time Series Analysis for Human Action Segmentation and Recognition.  

PubMed

We address the problem of structure learning of human motion to recognize actions from a continuous monocular motion sequence of an arbitrary person from an arbitrary viewpoint. Human motion sequences are represented by multivariate time series in the joint trajectories space. Under this structured time series framework, we first propose Kernelized Temporal Cut (KTC), an extension of previous works on change-point detection by incorporating Hilbert space embedding of distributions, to handle the nonparametric and high dimensionality issues. Experimental results demonstrate the effectiveness of our approach, which yields realtime segmentation, and produces high action segmentation accuracy. Second, a spatio-temporal manifold framework is proposed to model the latent structure of time series data. Then an efficient spatio-temporal alignment algorithm Dynamic Manifold Warping (DMW) is proposed for time series to calculate motion similarity between action sequences (segments). Furthermore, by combining the temporal segmentation algorithm and the alignment algorithm, online action recognition can be performed by associating a few labeled examples from motion capture data. The results on human motion capture data and 3D depth sensor data demonstrate the effectiveness of the proposed approach in segmenting and recognizing motion sequences, and its ability to handle noisy and partially occluded data, in the transfer learning module. PMID:24344075

Gong, Dian; Medioni, Gérard; Zhao, Xuemei

2013-12-11

107

Meteorological analysis models, volume 2  

NASA Technical Reports Server (NTRS)

As part of the SEASAT program, two sets of analysis programs were developed. One set of programs produce 63 x 63 horizontal mesh analyses on a polar stereographic grid. The other set produces 187 x 187 third mesh analyses. The parameters analyzed include sea surface temperature, sea level pressure and twelve levels of upper air temperature, height and wind analyses. Both sets use operational data provided by a weather bureau. The analysis output is used to initialize the primitive equation forecast models also included.

Langland, R. A.; Stark, D. L.

1976-01-01

108

Importance-performance analysis with benefit segmentation of spa goers  

Microsoft Academic Search

Purpose – Spas have become increasingly popular with consumers and have emerged as important profit centers for hotels. However, the uniqueness of this market has been largely overlooked in hospitality literature. The purpose of this paper is to fill the research gap by identifying different market segments among spa goers, based on a set of benefit variables. Design\\/methodology\\/approach – A

Suna Koh; Joanne Jung-Eun Yoo; Carl A. Boger Jr

2010-01-01

109

Diffraction analysis of LAMOST - two segmented mirrors included  

Microsoft Academic Search

LAMOST is a special reflecting Schmidt telescope. Both the reflecting Schmidt plate MA and the spherical primary mirror MB are segmented mirrors. These two cofocus but not co-phase. The diffraction of the optical system is decided by the shape overlapping of MA and MB. This paper describes the diffraction calculating results with different declination and different field angle. The diffraction

Wenli Xu

1996-01-01

110

Ethical segmentation of consumers in developing countries: a comparative analysis  

Microsoft Academic Search

Purpose – The purpose of this study is to segment the consumer Gulf market based on actionable and strategy yielding marketing variables (i.e. ethical orientations, trust, opportunisms and Machiavellianism). Design\\/methodology\\/approach – Consumers from Saudi Arabia, Oman and Kuwait were asked to complete a survey which incorporated scales to measure consumers' ethical beliefs, Machiavellianism, ethical orientation, opportunism, trust, as well as

Jamal A. Al-Khatib; Angela D'Auria Stanton; Mohammed Y. A. Rawwas

2005-01-01

111

Health Lifestyles: Audience Segmentation Analysis for Public Health Interventions.  

ERIC Educational Resources Information Center

This paper is concerned with the application of market research techniques to segment large populations into homogeneous units in order to improve the reach, utilization, and effectiveness of health programs. The paper identifies seven distinctive patterns of health attitudes, social influences, and behaviors using cluster analytic techniques in a…

Slater, Michael D.; Flora, June A.

112

Computer-assisted continuous ST-segment analysis for clinical research: methodological issues.  

PubMed

Continuous ST-segment monitoring has been used to detect acute myocardial ischemia, determine the success of the reperfusion therapy, and predict outcomes in both research and a variety of clinical settings. However, analyzing the abundant electrocardiography (ECG) data recorded using continuous multilead ST-segment monitoring techniques is time consuming and requires expertise. Experienced data interpreters in dedicated ECG core laboratories handle many continuous ECG data records from large clinical trials. Little information on measurement issues for computer-assisted ST-segment analysis is available for individual investigators. Unsupervised or inexperienced computer analysis of ST-segment deviations can, under certain circumstances, yield invalid or unreliable summary indices. The goal of this article is to discuss basic ST-segment measurement principles in evaluating acute myocardial ischemia and methodological issues surrounding the use of computer-assisted ST-segment analysis for continuous ECG data. Variables affecting ST-segment measurements will be examined. Sources and examples of variability for these potential errors will be identified. PMID:11931524

Wung, S F

2001-10-01

113

Failure analysis for model-based organ segmentation using outlier detection  

NASA Astrophysics Data System (ADS)

During the last years Model-Based Segmentation (MBS) techniques have been used in a broad range of medical applications. In clinical practice, such techniques are increasingly employed for diagnostic purposes and treatment decisions. However, it is not guaranteed that a segmentation algorithm will converge towards the desired solution. In specific situations as in the presence of rare anatomical variants (which cannot be represented) or for images with an extremely low quality, a meaningful segmentation might not be feasible. At the same time, an automated estimation of the segmentation reliability is commonly not available. In this paper we present an approach for the identification of segmentation failures using concepts from the field of outlier detection. The approach is validated on a comprehensive set of Computed Tomography Angiography (CTA) images by means of Receiver Operating Characteristic (ROC) analysis. Encouraging results in terms of an Area Under the ROC Curve (AUC) of up to 0.965 were achieved.

Saalbach, Axel; Wächter Stehle, Irina; Lorenz, Cristian; Weese, Jürgen

2014-03-01

114

Computed tomographic image analysis based on FEM performance comparison of segmentation on knee joint reconstruction.  

PubMed

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; Kim, Yoon Sang

2014-01-01

115

Who avoids going to the doctor and why? Audience segmentation analysis for application of message development.  

PubMed

This exploratory study examines the prevalent and detrimental health care phenomenon of patient delay in order to inform formative research leading to the design of communication strategies. Delayed medical care diminishes optimal treatment choices, negatively impacts prognosis, and increases medical costs. Various communication strategies have been employed to combat patient delay, with limited success. This study fills a gap in research informing those interventions by focusing on the portion of patient delay occurring after symptoms have been assessed as a sign of illness and the need for medical care has been determined. We used CHAID segmentation analysis to produce homogeneous segments from the sample according to the propensity to avoid medical care. CHAID is a criterion-based predictive cluster analysis technique. CHAID examines a variety of characteristics to find the one most strongly associated with avoiding doctor visits through a chi-squared test and assessment of statistical significance. The characteristics identified then define the segments. Fourteen segments were produced. Age was the first delineating characteristic, with younger age groups comprising a greater proportion of avoiders. Other segments containing a comparatively larger percent of avoiders were characterized by lower income, lower education, being uninsured, and being male. Each segment was assessed for psychographic properties associated with avoiding care, reasons for avoiding care, and trust in health information sources. While the segments display distinct profiles, having had positive provider experiences, having high health self-efficacy, and having an internal rather than external or chance locus of control were associated with low avoidance among several segments. Several segments were either more or less likely to cite time or money as the reason for avoiding care. And several older aged segments were less likely than the remaining sample to trust the government as a source for health information. Implications for future research are discussed. PMID:25062466

Kannan, Viji Diane; Veazie, Peter J

2015-07-01

116

Finite Volume Methods: Foundation and Analysis  

NASA Technical Reports Server (NTRS)

Finite volume methods are a class of discretization schemes that have proven highly successful in approximating the solution of a wide variety of conservation law systems. They are extensively used in fluid mechanics, porous media flow, meteorology, electromagnetics, models of biological processes, semi-conductor device simulation and many other engineering areas governed by conservative systems that can be written in integral control volume form. This article reviews elements of the foundation and analysis of modern finite volume methods. The primary advantages of these methods are numerical robustness through the obtention of discrete maximum (minimum) principles, applicability on very general unstructured meshes, and the intrinsic local conservation properties of the resulting schemes. Throughout this article, specific attention is given to scalar nonlinear hyperbolic conservation laws and the development of high order accurate schemes for discretizing them. A key tool in the design and analysis of finite volume schemes suitable for non-oscillatory discontinuity capturing is discrete maximum principle analysis. A number of building blocks used in the development of numerical schemes possessing local discrete maximum principles are reviewed in one and several space dimensions, e.g. monotone fluxes, E-fluxes, TVD discretization, non-oscillatory reconstruction, slope limiters, positive coefficient schemes, etc. When available, theoretical results concerning a priori and a posteriori error estimates are given. Further advanced topics are then considered such as high order time integration, discretization of diffusion terms and the extension to systems of nonlinear conservation laws.

Barth, Timothy; Ohlberger, Mario

2003-01-01

117

Rapid quantification of regurgitant flow through mitral valve models using the control volume method with segmented k-space magnetic resonance velocimetry  

Microsoft Academic Search

New approaches for the assessment of mitral regurgitation have focused on the quantification of the regurgitant flow volume, but they are accompanied by uncertainties. Recently, a control volume (CV) method applied via multi-slice and 3-directional magnetic resonance phase velocity mapping (MRPVM) showed potential for accurate quantification of the regurgitant volume. A limitation of conventional non-segmented MRPVM is its relatively long

H. Zhang; S. S. Halliburton; R. D. White; G. P. Chatzimavroudis

2002-01-01

118

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

119

A Linear Program Formulation for the Segmentation of Ciona Membrane Volumes  

E-print Network

-uniform and patchy membrane staining and faint spurious boundaries from other organelles (e.g. nuclei). Traditional stained [10]. 1 This work addresses the problem of cell segmentation, which is necessary to quantify059217 and NSF III-0808772. 1 The Ciona embryos were fixed, stained with Bodipy-FL phallicidin to label

California at Santa Barbara, University of

120

Segmental Hidden Markov Models for View-based Sport Video Analysis Yi Ding and Guoliang Fan  

E-print Network

Segmental Hidden Markov Models for View-based Sport Video Analysis Yi Ding and Guoliang Fan School in the game, e.g., advancing the ball. As a fundamental semantic structure, view-based sport video analysis field (www.okstate.com). There are mainly two methodologies for semantic-based video analysis, i

Fan, Guoliang

121

CONSUMER RESPONSE TO GENETICALLY MODIFIED FOODS: MARKET SEGMENT ANALYSIS AND IMPLICATIONS FOR PRODUCERS AND POLICY MAKERS  

Microsoft Academic Search

Conjoint analysis is used to elicit consumer preferences for attributes of genetically modified foods. Market segments are identified based on a cluster analysis of respondents' preferences for brand, price, and GMO content. A logit analysis is used to analyze consumer characteristics associated with the acceptance of GMO foods. Those consumers who were most risk averse, most likely to believe that

Gregory A. Baker; Thomas A. Burnham

2001-01-01

122

Combined texture feature analysis of segmentation and classification of benign and malignant tumour CT slices.  

PubMed

A computer software system is designed for the segmentation and classification of benign from malignant tumour slices in brain computed tomography (CT) images. This paper presents a method to find and select both the dominant run length and co-occurrence texture features of region of interest (ROI) of the tumour region of each slice to be segmented by Fuzzy c means clustering (FCM) and evaluate the performance of support vector machine (SVM)-based classifiers in classifying benign and malignant tumour slices. Two hundred and six tumour confirmed CT slices are considered in this study. A total of 17 texture features are extracted by a feature extraction procedure, and six features are selected using Principal Component Analysis (PCA). This study constructed the SVM-based classifier with the selected features and by comparing the segmentation results with the experienced radiologist labelled ground truth (target). Quantitative analysis between ground truth and segmented tumour is presented in terms of segmentation accuracy, segmentation error and overlap similarity measures such as the Jaccard index. The classification performance of the SVM-based classifier with the same selected features is also evaluated using a 10-fold cross-validation method. The proposed system provides some newly found texture features have an important contribution in classifying benign and malignant tumour slices efficiently and accurately with less computational time. The experimental results showed that the proposed system is able to achieve the highest segmentation and classification accuracy effectiveness as measured by jaccard index and sensitivity and specificity. PMID:23094909

Padma, A; Sukanesh, R

2013-01-01

123

FUZZY VERSUS HARD HIDDEN MARKOV CHAINS SEGMENTATION FOR VOLUME DETERMINATION AND QUANTITATION IN NOISY PET IMAGES  

E-print Network

IN NOISY PET IMAGES M. Hatt1 , N. Boussion1 , Member IEEE, F. Lamare1 , Student Member IEEE, C. Collet2 , F-conducteurs (PHASE), ULP, Strasbourg, France. ABSTRACT Accurate volume contouring in PET is crucial for quantitation for automatic lesion volume delineation that permit noise modelling and have not previously been applied to PET

124

Teeth segmentation of dental periapical radiographs based on local singularity analysis.  

PubMed

Teeth segmentation for periapical raidographs is one of the most critical tasks for effective periapical lesion or periodontitis detection, as both types of anomalies usually occur around tooth boundaries and dental radiographs are often subject to noise, low contrast, and uneven illumination. In this paper, we propose an effective scheme to segment each tooth in periapical radiographs. The method consists of four stages: image enhancement using adaptive power law transformation, local singularity analysis using Hölder exponent, tooth recognition using Otsu's thresholding and connected component analysis, and tooth delineation using snake boundary tracking and morphological operations. Experimental results of 28 periapical radiographs containing 106 teeth in total and 75 useful for dental examination demonstrate that 105 teeth are successfully isolated and segmented, and the overall mean segmentation accuracy of all 75 useful teeth in terms of (TP, FP) is (0.8959, 0.0093) with standard deviation (0.0737, 0.0096), respectively. PMID:24252317

Lin, P L; Huang, P Y; Huang, P W; Hsu, H C; Chen, C C

2014-02-01

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

Analysis of radially cracked ring segments subject to forces and couples  

NASA Technical Reports Server (NTRS)

Results of planar boundary collocation analysis are given for ring segment (C shaped) specimens with radial cracks, subjected to combined forces and couples. Mode I stress intensity factors and crack mouth opening displacements were determined for ratios of outer to inner radius in the range 1.1 to 2.5, and ratios of crack length to segment width in the range 0.1 to 0.8.

Gross, B.; Strawley, J. E.

1975-01-01

127

Two-stage neural network for volume segmentation of medical images  

Microsoft Academic Search

We present a system to segment and label CT\\/MRI brain slices using feature extraction and unsupervised clustering. In this technique, each voxel is assigned a feature pattern consisting of a scaled family of differential geometrical invariant features. The invariant feature pattern is then assigned to a specific region using a two-stage neural network system. The first stage is a self-organizing

Mohamed N. Ahmed; Aly A. Farag

1997-01-01

128

Analysis of wear mechanism and influence factors of drum segment of hot rolling coiler  

NASA Astrophysics Data System (ADS)

Because the work environment of segment is complex, and the wear failures usually happen, the wear mechanism corresponding to the load is a key factor for the solution of this problem. At present, many researchers have investigated the failure of segment, but have not taken into account the compositive influences of matching and coiling process. To investigate the wear failure of the drum segment of the hot rolling coiler, the MMU-5G abrasion tester is applied to simulate the wear behavior under different temperatures, different loads and different stages, and the friction coefficients and wear rates are acquired. Scanning electron microscopy(SEM) is used to observe the micro-morphology of worn surface, X-ray energy dispersive spectroscopy(EDS) is used to analyze the chemical composition of worn surface, finally the wear mechanism of segment in working process is judged and the influence regulars of the environmental factors on the material wear behaviors are found. The test and analysis results show that under certain load, the wear of the segment changes into oxidation wear from abrasive wear step by step with the temperature increases, and the wear degree reduces; under certain temperature, the main wear mechanism of segment changes into spalling wear from abrasive wear with the load increases, and the wear degree slightly increases. The proposed research provides a theoretical foundation and a practical reference for optimizing the wear behavior and extending the working life of segment.

Zhang, Jian; Peng, Yan; Liu, Hongmin; Liu, Yunfei

2013-03-01

129

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

PubMed

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 principal component analysis (PCA) is applied and results are used to train a support vector machine (SVM) classifier. During the segmentation stage, dental X-rays are classified first by the trained SVM. The classifier provides initial contours which are close to correct boundaries for three coupled level sets driven by a proposed pathologically variational modeling which greatly accelerates the level set segmentation. Based on the segmentation results and uncertainty maps that are built based on a proposed uncertainty measurement, a computer aided analysis scheme is applied. The experimental results show that the proposed method is able to provide an automatic pathological segmentation which naturally segments those problem areas. Based on the segmentation results, the analysis scheme is able to provide indications of possible problem areas of bone loss and decay to the dentists. As well, the experimental results show that the proposed segmentation framework is able to speed up the level set segmentation in clinical environments. PMID:16500077

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

2006-03-01

130

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

131

Automatic segmentation of the colon  

NASA Astrophysics Data System (ADS)

Virtual colonoscopy is a minimally invasive technique that enables detection of colorectal polyps and cancer. Normally, a patient's bowel is prepared with colonic lavage and gas insufflation prior to computed tomography (CT) scanning. An important step for 3D analysis of the image volume is segmentation of the colon. The high-contrast gas/tissue interface that exists in the colon lumen makes segmentation of the majority of the colon relatively easy; however, two factors inhibit automatic segmentation of the entire colon. First, the colon is not the only gas-filled organ in the data volume: lungs, small bowel, and stomach also meet this criteria. User-defined seed points placed in the colon lumen have previously been required to spatially isolate only the colon. Second, portions of the colon lumen may be obstructed by peristalsis, large masses, and/or residual feces. These complicating factors require increased user interaction during the segmentation process to isolate additional colon segments. To automate the segmentation of the colon, we have developed a method to locate seed points and segment the gas-filled lumen with no user supervision. We have also developed an automated approach to improve lumen segmentation by digitally removing residual contrast-enhanced fluid resulting from a new bowel preparation that liquefies and opacifies any residual feces.

Wyatt, Christopher L.; Ge, Yaorong; Vining, David J.

1999-05-01

132

Semiautomated three-dimensional segmentation software to quantify carpal bone volume changes on wrist CT scans for arthritis assessment  

PubMed Central

Rapid progression of joint destruction is an indication of poor prognosis in patients with rheumatoid arthritis. Computed tomography (CT) has the potential to serve as a gold standard for joint imaging since it provides high resolution three-dimensional (3D) images of bone structure. The authors have developed a method to quantify erosion volume changes on wrist CT scans. In this article they present a description and validation of the methodology using multiple scans of a hand phantom and five human subjects. An anthropomorphic hand phantom was imaged with a clinical CT scanner at three different orientations separated by a 30-deg angle. A reader used the semiautomated software tool to segment the individual carpal bones of each CT scan. Reproducibility was measured as the root-mean-square standard deviation (RMMSD) and coefficient of variation (CoV) between multiple measurements of the carpal volumes. Longitudinal erosion progression was studied by inserting simulated erosions in a paired second scan. The change in simulated erosion size was calculated by performing 3D image registration and measuring the volume difference between scans in a region adjacent to the simulated erosion. The RMSSD for the total carpal volumes was 21.0 mm3 (CoV=1.3%) for the phantom, and 44.1 mm3 (CoV=3.0%) for the in vivo subjects. Using 3D registration and local volume difference calculations, the RMMSD was 1.0?3.0 mm3. The reader time was approximately 5 min per carpal bone. There was excellent agreement between the measured and simulated erosion volumes. The effect of a poorly measured volume for a single erosion is mitigated by the large number of subjects that would comprise a clinical study and that there will be many erosions measured per patient. CT promises to be a quantifiable tool to measure erosion volumes and may serve as a gold standard that can be used in the validation of other modalities such as magnetic resonance imaging. PMID:18649465

Duryea, J.; Magalnick, M.; Alli, S.; Yao, L.; Wilson, M.; Goldbach-Mansky, R.

2008-01-01

133

Analysis of reassortment of genome segments in mice mixedly infected with rotaviruses SA11 and RRV.  

PubMed Central

Seven-day-old CD-1 mice born to seronegative dams were orally inoculated with a mixture of wild-type simian rotavirus SA11 and wild-type rhesus rotavirus RRV. At various times postinfection, progeny clones were randomly isolated from intestinal homogenates by limiting dilution. Analysis of genome RNAs by polyacrylamide gel electrophoresis was used to identify and genotype reassortant progeny. Reassortment of genome segments was observed in 252 of 662 (38%) clones analyzed from in vivo mixed infections. Kinetic studies indicated that reassortment was an early event in the in vivo infectious cycle; more than 25% of the progeny clones were reassortant by 12 h postinfection. The frequency of reassortant progeny increased to 80 to 100% by 72 to 96 h postinfection. A few reassortants with specific constellations of SA11 and RRV genome segments were repeatedly isolated from different litters or different animals within single litters, suggesting that these genotypes were independently and specifically selected in vivo. Analysis of segregation of individual genome segments among the 252 reassortant progeny revealed that, although most segments segregated randomly, segments 3 and 5 nonrandomly segregated from the SA11 parent. The possible selective pressures active during in vivo reassortment of rotavirus genome segments are discussed. Images PMID:3001336

Gombold, J L; Ramig, R F

1986-01-01

134

A robust and fast line segment detector based on top-down smaller eigenvalue analysis  

NASA Astrophysics Data System (ADS)

In this paper, we propose a robust and fast line segment detector, which achieves accurate results with a controlled number of false detections and requires no parameter tuning. It consists of three steps: first, we propose a novel edge point chaining method to extract Canny edge segments (i.e., contiguous chains of Canny edge points) from the input image; second, we propose a top-down scheme based on smaller eigenvalue analysis to extract line segments within each obtained edge segment; third, we employ Desolneux et al.'s method to reject false detections. Experiments demonstrate that it is very efficient and more robust than two state of the art methods—LSD and EDLines.

Liu, Dong; Wang, Yongtao; Tang, Zhi; Lu, Xiaoqing

2014-01-01

135

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

E-print Network

video structure analysis, using simple heuristics on occurrence patterns of the events discoveredUNSUPERVISED MINING OF AUDIOVISUALLY CONSISTENT SEGMENTS IN VIDEOS WITH APPLICATION TO STRUCTURE ANALYSIS Mathieu Ben INRIA Rennes 35042 Rennes Cedex, France mathieu.ben@inria.fr Guillaume Gravier IRISA

Paris-Sud XI, Université de

136

Error-tracking clustering gives quantitative statistics to DNA segmentation analysis  

E-print Network

Error-tracking clustering gives quantitative statistics to DNA segmentation analysis Chih-Hao Chen1 Abstract Inferences acquired by applying clustering analysis of microarrays cannot be reliably assessed present a novel and fast clustering technique, pair-wise Gaussian merging (PGM), suited for this purpose

Lee, H.C. Paul

137

Segmenting Business Students Using Cluster Analysis Applied to Student Satisfaction Survey Results  

ERIC Educational Resources Information Center

This paper demonstrates a new application of cluster analysis to segment business school students according to their degree of satisfaction with various aspects of the academic program. The resulting clusters provide additional insight into drivers of student satisfaction that are not evident from analysis of the responses of the student body as a…

Gibson, Allen

2009-01-01

138

Services considered important to business customers and determinants of bank selection in Kuwait: a segmentation analysis  

Microsoft Academic Search

Examines various segmentation analysis tools for bank marketing strategies. Aims to identify the relative importance of banking services to business customers’ needs, and to find out the true determinants of bank selection decisions. Profile analysis results revealed that Kuwaiti, non-Kuwaiti, and joint business firms are significantly different in their perceptions of the relative importance of many services offered by Kuwaiti

Thabet A. Edris

1997-01-01

139

Segmental hair analysis can demonstrate external contamination in postmortem cases.  

PubMed

Excluding laboratory mistakes, a false positive hair result can be observed in case of contamination from environmental pollution (external contamination) or after drug incorporation into the hair from the individual body fluids, such as sweat or putrefactive fluid (post mortem artifact). From our 20 years experience of hair testing, it appears that artifact(s) cannot be excluded in some post mortem cases, despite a decontamination procedure. As a consequence, interpretation of the results is a challenge that deserves particular attention. Our strategy will be reviewed in this paper, based on six cases. In all cases, a decontamination procedure with two washes of 5 ml of dichloromethane for 5 min was performed and the last dichloromethane wash was negative for each target drug. From the histories, there was no suspicion of chronic drug use. In all six cases, the concentrations detected were similar along the hair shaft, irrespective of the tested segment. We have considered this as indicative of external contamination and suggested to the forces or the judges that it is not possible to indicate exposure before death. In contrast to smoke, it seems that contamination due to aqueous matrices (sweat, putrefactive fluid, blood) is much more difficult to remove. To explain potential incorporation of 7-aminoflunitrazepam via putrefactive material, the author incubated negative hair strands in blood spiked at 100 ng/ml and stored at +4°C, room temperature and +40 °C for 7, 14 and 28 days. After routine decontamination, 7-aminoflunitrazepam tested positive in hair, irrespective of the incubation temperature, as early as after 7 days (233-401 pg/mg). In all periods, maximum concentrations were observed after incubation at room temperature. The highest concentration (742 pg/mg) was observed after 28 days incubation at room temperature. It is concluded that a standard decontamination procedure is not able to completely remove external contamination in case of post mortem specimens. Homogenous segmental analyses can be probably indicative of external contamination and therefore a single hair result should not be used to discriminate long-term exposure to a drug. Nor should the presence of a metabolite be considered as a discrimination tool, as it can also be present in putrefactive material. PMID:21354729

Kintz, Pascal

2012-02-10

140

Expression analysis of cloned chromosomal segments of Escherichia coli.  

PubMed Central

The novel transcription system of bacteriophage T7 was used to express Escherichia coli genes preferentially with a new low-copy-number plasmid vector, pFN476, to minimize toxic gene effects. Selected E. coli chromosomal fragments from an ordered genomic library (Y. Kohara, K. Ikiyama, and K. Isono, Cell 50:495-508, 1987) were recloned into this vector, and their genes were preferentially expressed in vivo utilizing its T7 promoter. The protein products were analyzed by two-dimensional gel electrophoresis. By using DNA sequence information, the gel migration was predicted for the protein products of open reading frames from these segments, and this information was used to identify gene products visualized as spots on two-dimensional gels. Even in the absence of DNA sequence information, this approach offers the opportunity to identify all gene products of E. coli and map their genes to within 10 kb on the E. coli genome; with sequence information, this approach can produce a definitive expression map of the E. coli genome. Images PMID:8349554

Sankar, P; Hutton, M E; VanBogelen, R A; Clark, R L; Neidhardt, F C

1993-01-01

141

Microreactors with integrated UV/Vis spectroscopic detection for online process analysis under segmented flow.  

PubMed

Combining reaction and detection in multiphase microfluidic flow is becoming increasingly important for accelerating process development in microreactors. We report the coupling of UV/Vis spectroscopy with microreactors for online process analysis under segmented flow conditions. Two integration schemes are presented: one uses a cross-type flow-through cell subsequent to a capillary microreactor for detection in the transmission mode; the other uses embedded waveguides on a microfluidic chip for detection in the evanescent wave field. Model experiments reveal the capabilities of the integrated systems in real-time concentration measurements and segmented flow characterization. The application of such integration for process analysis during gold nanoparticle synthesis is demonstrated, showing its great potential in process monitoring in microreactors operated under segmented flow. PMID:24178763

Yue, Jun; Falke, Floris H; Schouten, Jaap C; Nijhuis, T Alexander

2013-12-21

142

3-D segmentation and quantitative analysis of inner and outer walls of thrombotic abdominal aortic aneurysms  

NASA Astrophysics Data System (ADS)

An abdominal aortic aneurysm (AAA) is an area of a localized widening of the abdominal aorta, with a frequent presence of thrombus. A ruptured aneurysm can cause death due to severe internal bleeding. AAA thrombus segmentation and quantitative analysis are of paramount importance for diagnosis, risk assessment, and determination of treatment options. Until now, only a small number of methods for thrombus segmentation and analysis have been presented in the literature, either requiring substantial user interaction or exhibiting insufficient performance. We report a novel method offering minimal user interaction and high accuracy. Our thrombus segmentation method is composed of an initial automated luminal surface segmentation, followed by a cost function-based optimal segmentation of the inner and outer surfaces of the aortic wall. The approach utilizes the power and flexibility of the optimal triangle mesh-based 3-D graph search method, in which cost functions for thrombus inner and outer surfaces are based on gradient magnitudes. Sometimes local failures caused by image ambiguity occur, in which case several control points are used to guide the computer segmentation without the need to trace borders manually. Our method was tested in 9 MDCT image datasets (951 image slices). With the exception of a case in which the thrombus was highly eccentric, visually acceptable aortic lumen and thrombus segmentation results were achieved. No user interaction was used in 3 out of 8 datasets, and 7.80 +/- 2.71 mouse clicks per case / 0.083 +/- 0.035 mouse clicks per image slice were required in the remaining 5 datasets.

Lee, Kyungmoo; Yin, Yin; Wahle, Andreas; Olszewski, Mark E.; Sonka, Milan

2008-03-01

143

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

144

A COMPREHENSIVE ANALYSIS OF SWIFT XRT DATA. II. DIVERSE PHYSICAL ORIGINS OF THE SHALLOW DECAY SEGMENT  

E-print Network

Observations of the gamma-ray burst (GRB) phenomenon with the Swift satellite (Gehrels et al. 2004) haveA COMPREHENSIVE ANALYSIS OF SWIFT XRT DATA. II. DIVERSE PHYSICAL ORIGINS OF THE SHALLOW DECAY ABSTRACT The origin of the shallow decay segment in Swift XRT light curves remains a puzzle. We analyze

Zhang, Bing

145

Smoothly continuous road centre-line segments as a basis for road network analysis  

Microsoft Academic Search

This paper presents the use of smoothly continuous road centre-line segments - which are here termed strokes - as a useful basis for the analysis of street and road networks. The decomposition of networks into linear strokes, which show good continuation of direction and continuity of character (width or type), has been found to provide a basis for robust, effective,

Robert C. Thomson

146

3D segmentation using interval analysis and pre-attentive behaviour for a humanoid robot  

Microsoft Academic Search

This paper presents a 3D object segmentation algorithm based on dense 3D map provided by a stereoscopic vision system. The novelty of this paper is to use interval analysis for deciding to which region a 3D point should be merged with. This algorithm is used to implement an exploration behaviour on the HRP-2 humanoid robot

Olivier Stasse; Benoît Telle; Kazuhito Yokoi

2005-01-01

147

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

148

Three-dimensional segmented poincare plot analysis - A new approach of cardiovascular and cardiorespiratory regulation analysis.  

PubMed

Hypertensive pregnancy disorders affect 6 to 8 percent of all pregnancies which can cause severe complications for the mother and the fetus. The aim of this study was to develop a new method suitable for a three dimensional coupling analysis. Therefore, the three-dimensional segmented Poincare? plot analysis (SPPA3) is introduced that represents the Poincare analysis based on a cubic box model representation. The box representing the three dimensional phase space is (based on the SPPA method) subdivided into 12×12×12 equal cubelets according to the predefined range of signals and all single probabilities of occurring points in a specific cubelet related to the total number of points are calculated. From 10 healthy non-pregnant women, 66 healthy pregnant women and 56 hypertensive pregnant women suffering from chronic hypertension, gestational hypertension and preeclampsia, 30 minutes of beat-to-beat intervals (BBI), noninvasive blood pressure and respiration (RESP) were continuously recorded and analyzed. Couplings between the different signals were analyzed. The ability of SPPA3 for a screening could be confirmed by multivariate discriminant analysis differentiating between all pregnant woman and preeclampsia (index BBI3_SBP9_RESP6/ BBI8_SBP11_RESP4 leads to an area under the ROC curve of AUC=91.2%). In conclusion, SPPA3 could be a useful method for enhanced risk stratification in pregnant women. PMID:25571367

Fischer, Claudia; Voss, Andreas

2014-01-01

149

Mathematical analysis on deformation and movement features with stressed lap to off-axis segment  

NASA Astrophysics Data System (ADS)

Through mathematical analysis and calculation, the author considers that the former mechanical structure(used to axial-symmetrical asphere) must be modified when being used to off-axis segment. This point is different from Dr. H.M.Martin[3]. The author puts forward two mechanical structures, electrical control types, and draws up feature graphs of movement, deformation and hoist etc. then to analyze the moving and deforming features of stressed lap on off-axis segment. At last the author gives new imagination for look-up tables and how to read out data.

Gao, Bilie

2007-12-01

150

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

E-print Network

segmentation in a data mining system United States Patent 7069197 Abstract: A computer-implemented data mining system that analyzes customer transaction data using Factor Analysis/Retail Data Mining Segmentation 1 Patents Citing Fionn Murtagh's Work on: Clustering (1) Factor analysis/retail data mining

Murtagh, Fionn

151

Segmentation of Video by Clustering and Graph Analysis  

Microsoft Academic Search

Many video programs have story structures that can be recognized through the clustering of video contents based on low-level visual primitives and the analysis of high-level structures imposed by temporal arrangement of composing elements. In this paper we propose techniques and formulations to match and cluster video shots of similar visual contents, taking into account the visual characteristics and temporal

Minerva M. Yeung; Boon-lock Yeo; Bede Liu

1998-01-01

152

Unsupervised synthetic aperture radar image segmentation with superpixels in independent space based on independent component analysis  

NASA Astrophysics Data System (ADS)

Synthetic aperture radar (SAR) image segmentation is a challenging problem in recent years because of the speckle noise. An unsupervised SAR image segmentation with superpixels by independent component analysis (ICA) is proposed. ICA independent space is proposed to represent SAR images for feature extraction effectively. First, the SAR image is divided into small regions by mean-shift algorithm and then those regions are merged in region adjacent graph and full-connected graph based on the Mining Spanning Tree theory, which balances the speed and quality of segmentation. Finally, experiments on X-band TerraSAR images and comparisons with simple linear iterative clustering and graph-cut illustrate the excellent performance of the new method.

Ji, Jian; Li, Xiao-yuan

2014-01-01

153

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

154

Comparison of Acute and Chronic Traumatic Brain Injury Using Semi-Automatic Multimodal Segmentation of MR Volumes  

PubMed Central

Abstract Although neuroimaging is essential for prompt and proper management of traumatic brain injury (TBI), there is a regrettable and acute lack of robust methods for the visualization and assessment of TBI pathophysiology, especially for of the purpose of improving clinical outcome metrics. Until now, the application of automatic segmentation algorithms to TBI in a clinical setting has remained an elusive goal because existing methods have, for the most part, been insufficiently robust to faithfully capture TBI-related changes in brain anatomy. This article introduces and illustrates the combined use of multimodal TBI segmentation and time point comparison using 3D Slicer, a widely-used software environment whose TBI data processing solutions are openly available. For three representative TBI cases, semi-automatic tissue classification and 3D model generation are performed to perform intra-patient time point comparison of TBI using multimodal volumetrics and clinical atrophy measures. Identification and quantitative assessment of extra- and intra-cortical bleeding, lesions, edema, and diffuse axonal injury are demonstrated. The proposed tools allow cross-correlation of multimodal metrics from structural imaging (e.g., structural volume, atrophy measurements) with clinical outcome variables and other potential factors predictive of recovery. In addition, the workflows described are suitable for TBI clinical practice and patient monitoring, particularly for assessing damage extent and for the measurement of neuroanatomical change over time. With knowledge of general location, extent, and degree of change, such metrics can be associated with clinical measures and subsequently used to suggest viable treatment options. PMID:21787171

Chambers, Micah C.; Alger, Jeffry R.; Filippou, Maria; Prastawa, Marcel W.; Wang, Bo; Hovda, David A.; Gerig, Guido; Toga, Arthur W.; Kikinis, Ron; Vespa, Paul M.; Van Horn, John D.

2011-01-01

155

Development of an automated 3D segmentation program for volume quantification of body fat distribution using CT.  

PubMed

The objective of this study was to develop a computing tool for full-automatic segmentation of body fat distributions on volumetric CT images. We developed an algorithm to automatically identify the body perimeter and the inner contour that separates visceral fat from subcutaneous fat. Diaphragmatic surfaces can be extracted by model-based segmentation to match the bottom surface of the lung in CT images for determination of the upper limitation of the abdomen. The functions for quantitative evaluation of abdominal obesity or obesity-related metabolic syndrome were implemented with a prototype three-dimensional (3D) image processing workstation. The volumetric ratios of visceral fat to total fat and visceral fat to subcutaneous fat for each subject can be calculated. Additionally, color intensity mapping of subcutaneous areas and the visceral fat layer is quite obvious in understanding the risk of abdominal obesity with the 3D surface display. Preliminary results obtained have been useful in medical checkups and have contributed to improved efficiency in checking obesity throughout the whole range of the abdomen with 3D visualization and analysis. PMID:18840956

Ohshima, Shunsuke; Yamamoto, Shuji; Yamaji, Taiki; Suzuki, Masahiro; Mutoh, Michihiro; Iwasaki, Motoki; Sasazuki, Shizuka; Kotera, Ken; Tsugane, Shoichiro; Muramatsu, Yukio; Moriyama, Noriyuki

2008-09-20

156

The Impact of Policy Guidelines on Hospital Antibiotic Use over a Decade: A Segmented Time Series Analysis  

PubMed Central

Introduction Antibiotic pressure contributes to rising antibiotic resistance. Policy guidelines encourage rational prescribing behavior, but effectiveness in containing antibiotic use needs further assessment. This study therefore assessed the patterns of antibiotic use over a decade and analyzed the impact of different modes of guideline development and dissemination on inpatient antibiotic use. Methods Antibiotic use was calculated monthly as defined daily doses (DDD) per 100 bed days for nine antibiotic groups and overall. This time series compared trends in antibiotic use in five adjacent time periods identified as ‘Segments,’ divided based on differing modes of guideline development and implementation: Segment 1– Baseline prior to antibiotic guidelines development; Segment 2– During preparation of guidelines and booklet dissemination; Segment 3– Dormant period with no guidelines dissemination; Segment 4– Booklet dissemination of revised guidelines; Segment 5– Booklet dissemination of revised guidelines with intranet access. Regression analysis adapted for segmented time series and adjusted for seasonality assessed changes in antibiotic use trend. Results Overall antibiotic use increased at a monthly rate of 0.95 (SE?=?0.18), 0.21 (SE?=?0.08) and 0.31 (SE?=?0.06) for Segments 1, 2 and 3, stabilized in Segment 4 (0.05; SE?=?0.10) and declined in Segment 5 (?0.37; SE?=?0.11). Segments 1, 2 and 4 exhibited seasonal fluctuations. Pairwise segmented regression adjusted for seasonality revealed a significant drop in monthly antibiotic use of 0.401 (SE?=?0.089; p<0.001) for Segment 5 compared to Segment 4. Most antibiotic groups showed similar trends to overall use. Conclusion Use of overall and specific antibiotic groups showed varied patterns and seasonal fluctuations. Containment of rising overall antibiotic use was possible during periods of active guideline dissemination. Wider access through intranet facilitated significant decline in use. Stakeholders and policy makers are urged to develop guidelines, ensure active dissemination and enable accessibility through computer networks to contain antibiotic use and decrease antibiotic pressure. PMID:24647339

Chandy, Sujith J.; Naik, Girish S.; Charles, Reni; Jeyaseelan, Visalakshi; Naumova, Elena N.; Thomas, Kurien; Lundborg, Cecilia Stalsby

2014-01-01

157

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

158

Brain MRI Segmentation Using an Expectation-Maximization  

E-print Network

-dimensional (3-D) High soft tissue contrast High spatial resolution Possibly multi-spectral Non-rater variability multi-spectral input is hard to interpret Routine analysis is impractical Need for automated Modeling MR bias fields Multiple Sclerosis lesion segmentation Partial volume segmentation Discussion

159

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

160

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

161

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

162

Segmentation fusion for connectomics  

Microsoft Academic Search

We address the problem of automatic 3D segmentation of a stack of electron microscopy sections of brain tissue. Unlike previous efforts, where the reconstruction is usually done on a section-to-section basis, or by the agglomerative clustering of 2D segments, we leverage information from the entire volume to obtain a globally optimal 3D segmentation. To do this, we formulate the segmentation

Amelio Vazquez-Reina; Michael Gelbart; Daniel Huang; Jeff Lichtman; Eric Miller; Hanspeter Pfister

2011-01-01

163

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

PubMed Central

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 R2 = 0.200 (coefficient of determination) in contrast to MCG/fABAS related multivariate models with R2 = 0.648 in 30 min recordings, R2 = 0.610 in active sleep segments of 10 min, and R2 = 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 R2 = 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

164

Histological analysis of the callogenesis and organogenesis from root segments of Curcuma zedoaria Roscoe  

Microsoft Academic Search

Callus was induced from root segments taken from in vitro grown plants of Curcuma zedoaria Roscoe. The explants were cultured on agar-solidified Murashige and Skoog medium supplemented with 13.4?M of ?-naphthaleneacetic acid and 2.2?M of 6-benzylaminopurine at 25ºC in the dark. Histological analysis revealed that callus was formed from the hypertrophied cortical parenchyma cells of the explant. Some of these

Marcia O. Mello; Murilo Melo; Beatriz Appezzato-da-Glória

2001-01-01

165

Hemodynamic segmentation of MR brain perfusion images using independent component analysis, thresholding, and Bayesian estimation  

Microsoft Academic Search

Dynamic-susceptibility-contrast MR perfusion imaging is a widely used imaging tool for in vivo study of cerebral blood perfusion. However, visualization of different hemodynamic compartments is less investigated. In this work, independent component analysis, thresholding, and Bayesian estimation were used to concurrently segment different tissues, i.e., artery, gray matter, white matter, vein and sinus, choroid plexus, and cerebral spinal fluid, with

Yi-Hsuan Kao; Wan-Yuo Guo; Yu-Te Wu; Kuo-Ching Liu; Wen-Yen Chai; Chiao-Yuan Lin; Yi-Shuan Hwang; Adrain Jy-Kang Liou; Hsiu-Mei Wu; Hui-Cheng Cheng; Tzu-Chen Yeh; Jen-Chuen Hsieh; Michael Mu Huo Teng

2003-01-01

166

A multi-scale segmentation\\/object relationship modelling methodology for landscape analysis  

Microsoft Academic Search

Natural complexity can best be explored using spatial analysis tools based on concepts of landscape as process continuums that can be partially decomposed into objects or patches. We introduce a five-step methodology based on multi-scale segmentation and object relationship modelling. Hierarchical patch dynamics (HPD) is adopted as the theoretical framework to address issues of heterogeneity, scale, connectivity and quasi-equilibriums in

C. Burnett; Thomas Blaschke

2003-01-01

167

Fully Bayesian Inference for Structural MRI: Application to Segmentation and Statistical Analysis of T2-Hypointensities  

PubMed Central

Aiming at iron-related T2-hypointensity, which is related to normal aging and neurodegenerative processes, we here present two practicable approaches, based on Bayesian inference, for preprocessing and statistical analysis of a complex set of structural MRI data. In particular, Markov Chain Monte Carlo methods were used to simulate posterior distributions. First, we rendered a segmentation algorithm that uses outlier detection based on model checking techniques within a Bayesian mixture model. Second, we rendered an analytical tool comprising a Bayesian regression model with smoothness priors (in the form of Gaussian Markov random fields) mitigating the necessity to smooth data prior to statistical analysis. For validation, we used simulated data and MRI data of 27 healthy controls (age: ; range, ). We first observed robust segmentation of both simulated T2-hypointensities and gray-matter regions known to be T2-hypointense. Second, simulated data and images of segmented T2-hypointensity were analyzed. We found not only robust identification of simulated effects but also a biologically plausible age-related increase of T2-hypointensity primarily within the dentate nucleus but also within the globus pallidus, substantia nigra, and red nucleus. Our results indicate that fully Bayesian inference can successfully be applied for preprocessing and statistical analysis of structural MRI data. PMID:23874537

Schmidt, Paul; Schmid, Volker J.; Gaser, Christian; Buck, Dorothea; Bührlen, Susanne; Förschler, Annette; Mühlau, Mark

2013-01-01

168

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

169

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

170

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

171

Optimal analysis for segmented mirror capture and alignment in space optics system  

Microsoft Academic Search

A great deal segmented mirror errors consisting of piston and tip-tilt exist when space large aperture segmented optics system deploys. These errors will result in the departure of segmented mirrors images from the view. For that, proper scanning function should be adopted to control actuators rotating the segmented mirror, so that the images of segmented mirror can be put into

Xiaofang Zhang; Xin Yu; Xia Wang; Lei Zhao

2008-01-01

172

FEM correlation and shock analysis of a VNC MEMS mirror segment  

NASA Astrophysics Data System (ADS)

Microelectromechanical systems (MEMS) are becoming more prevalent in today's advanced space technologies. The Visible Nulling Coronagraph (VNC) instrument, being developed at the NASA Goddard Space Flight Center, uses a MEMS Mirror to correct wavefront errors. This MEMS Mirror, the Multiple Mirror Array (MMA), is a key component that will enable the VNC instrument to detect Jupiter and ultimately Earth size exoplanets. Like other MEMS devices, the MMA faces several challenges associated with spaceflight. Therefore, Finite Element Analysis (FEA) is being used to predict the behavior of a single MMA segment under different spaceflight-related environments. Finite Element Analysis results are used to guide the MMA design and ensure its survival during launch and mission operations. A Finite Element Model (FEM) has been developed of the MMA using COMSOL. This model has been correlated to static loading on test specimens. The correlation was performed in several steps—simple beam models were correlated initially, followed by increasingly complex and higher fidelity models of the MMA mirror segment. Subsequently, the model has been used to predict the dynamic behavior and stresses of the MMA segment in a representative spaceflight mechanical shock environment. The results of the correlation and the stresses associated with a shock event are presented herein.

Aguayo, Eduardo J.; Lyon, Richard; Helmbrecht, Michael; Khomusi, Sausan

2014-08-01

173

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

174

Phylogenetic and recombination analysis of rice black-streaked dwarf virus segment 9 in China.  

PubMed

Rice black-streaked dwarf virus (RBSDV) is an economically important virus that causes maize rough dwarf disease and rice black-streaked dwarf disease in East Asia. To study RBSDV variation and recombination, we examined the segment 9 (S9) sequences of 49 RBSDV isolates from maize and rice in China. Three S9 recombinants were detected in Baoding, Jinan, and Jining, China. Phylogenetic analysis showed that Chinese RBSDV isolates could be classified into two groups based on their S9 sequences, regardless of host or geographical origin. Further analysis suggested that S9 has undergone negative and purifying selection. PMID:25633210

Zhou, Yu; Weng, Jian-Feng; Chen, Yan-Ping; Liu, Chang-Lin; Han, Xiao-Hua; Hao, Zhuan-Fang; Li, Ming-Shun; Yong, Hong-Jun; Zhang, De-Gui; Zhang, Shi-Huang; Li, Xin-Hai

2015-04-01

175

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

176

Multiresolution analysis using wavelet, ridgelet, and curvelet transforms for medical image segmentation.  

PubMed

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

177

Analysis of an open crown conical shell segment for edge loadings and a linearly varying normal surface loading  

E-print Network

ANALYSIS OF AN OPEN CROWN CONICAL SHELL SEGMENT FOR EDGE LOADIHGS AND A LINEARLY VARYING NORMAL SURFACE LOADING A Thesis DONALD GABLE HERVEY Submitted to the Graduate College of the Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1965 Ma/or Subject: Mechanical Engineering ANALYSIS OF AN OPEN CROWN CONICAL SHELL SEGMENT FOR EDGE LOADINGS AND A LINEARLY VARYING NORMAL SURFACE LOADING A Thesis by DONALD GABLE HERVEY Approved...

Hervey, Donald Gable

1965-01-01

178

Profiling the different needs and expectations of patients for population-based medicine: a case study using segmentation analysis  

PubMed Central

Background This study illustrates an evidence-based method for the segmentation analysis of patients that could greatly improve the approach to population-based medicine, by filling a gap in the empirical analysis of this topic. Segmentation facilitates individual patient care in the context of the culture, health status, and the health needs of the entire population to which that patient belongs. Because many health systems are engaged in developing better chronic care management initiatives, patient profiles are critical to understanding whether some patients can move toward effective self-management and can play a central role in determining their own care, which fosters a sense of responsibility for their own health. A review of the literature on patient segmentation provided the background for this research. Method First, we conducted a literature review on patient satisfaction and segmentation to build a survey. Then, we performed 3,461 surveys of outpatient services users. The key structures on which the subjects’ perception of outpatient services was based were extrapolated using principal component factor analysis with varimax rotation. After the factor analysis, segmentation was performed through cluster analysis to better analyze the influence of individual attitudes on the results. Results Four segments were identified through factor and cluster analysis: the “unpretentious,” the “informed and supported,” the “experts” and the “advanced” patients. Their policies and managerial implications are outlined. Conclusions With this research, we provide the following: – a method for profiling patients based on common patient satisfaction surveys that is easily replicable in all health systems and contexts; – a proposal for segments based on the results of a broad-based analysis conducted in the Italian National Health System (INHS). Segments represent profiles of patients requiring different strategies for delivering health services. Their knowledge and analysis might support an effort to build an effective population-based medicine approach. PMID:23256543

2012-01-01

179

An analysis of the segmentation threshold used in axial-shear strain elastography.  

PubMed

Axial-shear strain elastography was introduced recently to image the tumor-host tissue boundary bonding characteristics. The image depicting the axial-shear strain distribution in a tissue under axial compression was termed as an axial-shear strain elastogram (ASSE). It has been demonstrated through simulation, tissue-mimicking phantom experiments, and retrospective analysis of in vivo breast lesion data that metrics quantifying the pattern of axial-shear strain distribution on ASSE can be used as features for identifying the lesion boundary condition as loosely-bonded or firmly-bonded. Consequently, features from ASSE have been shown to have potential in non-invasive breast lesion classification into benign versus malignant. Although there appears to be a broad concurrence in the results reported by different groups, important details pertaining to the appropriate segmentation threshold needed for - (1) displaying the ASSE as a color-overlay on top of corresponding Axial Strain Elastogram (ASE) and/or sonogram for feature visualization and (2) ASSE feature extraction are not yet fully addressed. In this study, we utilize ASSE from tissue mimicking phantom (with loosely-bonded and firmly-bonded inclusions) experiments and freehand - acquired in vivo breast lesion data (7 benign and 9 malignant) to analyze the effect of segmentation threshold on ASSE feature value, specifically, the "fill-in" feature that was introduced recently. We varied the segmentation threshold from 20% to 70% (of the maximum ASSE value) for each frame of the acquisition cine-loop of every data and computed the number of ASSE pixels within the lesion that was greater than or equal to this threshold value. If at least 40% of the pixels within the lesion area crossed this segmentation threshold, the ASSE frame was considered to demonstrate a "fill-in" that would indicate a loosely-bonded lesion boundary condition (suggestive of a benign lesion). Otherwise, the ASSE frame was considered not to demonstrate a "fill-in" indicating a firmly-bonded lesion boundary condition (suggestive of a malignant lesion). The results demonstrate that in the case of in vivo breast lesion data the appropriate range for the segmentation threshold value seems to be 40-60%. It was noted that for a segmentation threshold within this range (for example, at 50%) all of the analyzed breast lesion cases can be correctly classified into benign and malignant, based on the percentage number of frames within the acquisition cine-loop that demonstrate a "fill-in". PMID:25173068

Thittai, Arun K; Xia, Rongmin

2015-01-01

180

Coupled-wave analysis of apodized volume gratings  

E-print Network

a method for creating apodization in volume holograms with approximately Gaussian spatial refractive indexCoupled-wave analysis of apodized volume gratings J.M. Tsui and C. Thompson University: This work presents the use of longitudinal refractive index modulation (apodization) in photosensitive glass

Glebov, Leon

181

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

182

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

PubMed Central

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 analysing 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 expression 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. PMID:22487793

Kwak, In Hae; Son, Minjun; Hagen, Stephen J.

2012-01-01

183

Advanced finite element analysis of L4-L5 implanted spine segment  

NASA Astrophysics Data System (ADS)

In the paper finite element (FE) analysis of implanted lumbar spine segment is presented. The segment model consists of two lumbar vertebrae L4 and L5 and the prosthesis. The model of the intervertebral disc prosthesis consists of two metallic plates and a polyurethane core. Bone tissue is modelled as a linear viscoelastic material. The prosthesis core is made of a polyurethane nanocomposite. It is modelled as a non-linear viscoelastic material. The constitutive law of the core, derived in one of the previous papers, is implemented into the FE software Abaqus®. It was done by means of the User-supplied procedure UMAT. The metallic plates are elastic. The most important parts of the paper include: description of the prosthesis geometrical and numerical modelling, mathematical derivation of stiffness tensor and Kirchhoff stress and implementation of the constitutive model of the polyurethane core into Abaqus® software. Two load cases were considered, i.e. compression and stress relaxation under constant displacement. The goal of the paper is to numerically validate the constitutive law, which was previously formulated, and to perform advanced FE analyses of the implanted L4-L5 spine segment in which non-standard constitutive law for one of the model materials, i.e. the prosthesis core, is implemented.

Pawlikowski, Marek; Doma?ski, Janusz; Suchocki, Cyprian

2014-03-01

184

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

185

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

186

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

187

Segmentation of biological target volumes on multi-tracer PET images based on information fusion for achieving dose painting in radiotherapy.  

PubMed

Medical imaging plays an important role in radiotherapy. Dose painting consists in the application of a nonuniform dose prescription on a tumoral region, and is based on an efficient segmentation of biological target volumes (BTV). It is derived from PET images, that highlight tumoral regions of enhanced glucose metabolism (FDG), cell proliferation (FLT) and hypoxia (FMiso). In this paper, a framework based on Belief Function Theory is proposed for BTV segmentation and for creating 3D parametric images for dose painting. We propose to take advantage of neighboring voxels for BTV segmentation, and also multi-tracer PET images using information fusion to create parametric images. The performances of BTV segmentation was evaluated on an anthropomorphic phantom and compared with two other methods. Quantitative results show the good performances of our method. It has been applied to data of five patients suffering from lung cancer. Parametric images show promising results by highlighting areas where a high frequency or dose escalation could be planned. PMID:23285594

Lelandais, Benoît; Gardin, Isabelle; Mouchard, Laurent; Vera, Pierre; Ruan, Su

2012-01-01

188

Sequence analysis of Indian iris yellow spot virus ambisense genome segments: evidence of interspecies RNA recombination.  

PubMed

The nucleotide sequence of M- and S-RNA segments of an Indian iris yellow spot virus (IYSV) were determined. Sequence comparisons showed that both of these sequences shared less than 95 % identity with those other known IYSV isolates. Phylogenetic analysis revealed that the S- and M-RNA sequences of known IYSV isolates clustered with those of the tospoviruses, tomato yellow ring virus, polygonum ringspot virus and hippeastrum chlorotic ringspot virus. Further, multiple recombination detection methods detected inter- and intra-species recombination events that clustered primarily within the intergenic regions of S- and M-RNA, suggesting that these are possibly recombination hotspots in IYSV and closely related tospoviruses. PMID:25655262

Gawande, S J; Gurav, V S; Ingle, A A; Martin, D P; Asokan, R; Gopal, J

2015-05-01

189

Surface Analysis from Video Volumes for Fetal Alcohol Syndrome Classification  

Microsoft Academic Search

3D shape reconstruction is often a necessary step to obtain geometric information from multiple 2D images for shape analysis. In this paper, a new shape analysis technique is proposed using surface features derived directly from the video volume of 2D images. It avoids the explicit 3D reconstruction process, which is often not very robust and accurate for surface feature analysis.

Shiaofen Fang; Ying Liu; Sophia Vinci-Booher; Bruce Anthony; Feng Zhou

2010-01-01

190

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

191

Volume accumulator design analysis computer codes  

NASA Technical Reports Server (NTRS)

The computer codes, VANEP and VANES, were written and used to aid in the design and performance calculation of the volume accumulator units (VAU) for the 5-kwe reactor thermoelectric system. VANEP computes the VAU design which meets the primary coolant loop VAU volume and pressure performance requirements. VANES computes the performance of the VAU design, determined from the VANEP code, at the conditions of the secondary coolant loop. The codes can also compute the performance characteristics of the VAU's under conditions of possible modes of failure which still permit continued system operation.

Whitaker, W. D.; Shimazaki, T. T.

1973-01-01

192

Internet Segmentation  

Microsoft Academic Search

Two of the most interesting and useful aspects of the Internet marketplace are providing research and targeting specific marketing segments. A plethora of free information on Net users and their habits exists on the Web. In addition, marketers can conduct their own online research inexpensively through e-mail and a variety of Websites analysis tools. Target marketing on the Web means

Susie Chang

1998-01-01

193

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

194

An automated target recognition technique for image segmentation and scene analysis  

SciTech Connect

Automated target recognition software has been designed to perform image segmentation and scene analysis. Specifically, this software was developed as a package for the Army`s Minefield and Reconnaissance and Detector (MIRADOR) program. MIRADOR is an on/off road, remote control, multi-sensor system designed to detect buried and surface-emplaced metallic and non-metallic anti-tank mines. The basic requirements for this ATR software were: (1) an ability to separate target objects from the background in low S/N conditions; (2) an ability to handle a relatively high dynamic range in imaging light levels; (3) the ability to compensate for or remove light source effects such as shadows; and (4) the ability to identify target objects as mines. The image segmentation and target evaluation was performed utilizing an integrated and parallel processing approach. Three basic techniques (texture analysis, edge enhancement, and contrast enhancement) were used collectively to extract all potential mine target shapes from the basic image. Target evaluation was then performed using a combination of size, geometrical, and fractal characteristics which resulted in a calculated probability for each target shape. Overall results with this algorithm were quite good, though there is a trade-off between detection confidence and the number of false alarms. This technology also has applications in the areas of hazardous waste site remediation, archaeology, and law enforcement.

Baumgart, C.W.; Ciarcia, C.A.

1994-02-01

195

Sequence and phylogenetic analysis of M-class genome segments of novel duck reovirus NP03.  

PubMed

We report the sequence and phylogenetic analysis of the entire M1, M2, and M3 genome segments of the novel duck reovirus (NDRV) NP03. Alignment between the newly determined nucleotide sequences as well as their deduced amino acid sequences and the published sequences of avian reovirus (ARV) was carried out with DNASTAR software. Sequence comparison showed that the M2 gene had the most variability among the M-class genes of DRV. Phylogenetic analysis of the M-class genes of ARV strains revealed different lineages and clusters within DRVs. The 5 NDRV strains used in this study fall into a well-supported lineage that includes chicken ARV strains, whereas Muscovy DRV (MDRV) strains are separate from NDRV strains and form a distinct genetic lineage in the M2 gene tree. However, the MDRV and NDRV strains are closely related and located in a common lineage in the M1 and M3 gene trees, respectively. PMID:25852231

Wang, Shao; Chen, Shilong; Cheng, Xiaoxia; Chen, Shaoying; Lin, FengQiang; Jiang, Bing; Zhu, Xiaoli; Li, Zhaolong; Wang, Jinxiang

2015-04-01

196

Design and analysis of modules for segmented X-ray optics  

NASA Astrophysics Data System (ADS)

Lightweight and high resolution mirrors are needed for future space-based X-ray telescopes to achieve advances in high-energy astrophysics. The slumped glass mirror technology in development at NASA GSFC aims to build X-ray mirror modules with an area to mass ratio of ~17 cm2/kg at 1 keV and a resolution of 10 arc-sec Half Power Diameter (HPD) or better at an affordable cost. As the technology nears the performance requirements, additional engineering effort is needed to ensure the modules are compatible with space-flight. This paper describes Flight Mirror Assembly (FMA) designs for several X-ray astrophysics missions studied by NASA and defines generic driving requirements and subsequent verification tests necessary to advance technology readiness for mission implementation. The requirement to perform X-ray testing in a horizontal beam, based on the orientation of existing facilities, is particularly burdensome on the mirror technology, necessitating mechanical over-constraint of the mirror segments and stiffening of the modules in order to prevent self-weight deformation errors from dominating the measured performance. This requirement, in turn, drives the mass and complexity of the system while limiting the testable angular resolution. Design options for a vertical X-ray test facility alleviating these issues are explored. An alternate mirror and module design using kinematic constraint of the mirror segments, enabled by a vertical test facility, is proposed. The kinematic mounting concept has significant advantages including potential for higher angular resolution, simplified mirror integration, and relaxed thermal requirements. However, it presents new challenges including low vibration modes and imperfections in kinematic constraint. Implementation concepts overcoming these challenges are described along with preliminary test and analysis results demonstrating the feasibility of kinematically mounting slumped glass mirror segments.

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

2012-09-01

197

Segmentation and volumetric measurement of renal cysts and parenchyma from MR images of polycystic kidneys using multi-spectral analysis method  

NASA Astrophysics Data System (ADS)

For segmentation and volume measurement of renal cysts and parenchyma from kidney MR images in subjects with autosomal dominant polycystic kidney disease (ADPKD), a semi-automated, multi-spectral anaylsis (MSA) method was developed and applied to T1- and T2-weighted MR images. In this method, renal cysts and parenchyma were characterized and segmented for their characteristic T1 and T2 signal intensity differences. The performance of the MSA segmentation method was tested on ADPKD phantoms and patients. Segmented renal cysts and parenchyma volumes were measured and compared with reference standard measurements by fluid displacement method in the phantoms and stereology and region-based thresholding methods in patients, respectively. As results, renal cysts and parenchyma were segmented successfully with the MSA method. The volume measurements obtained with MSA were in good agreement with the measurements by other segmentation methods for both phantoms and subjects. The MSA method, however, was more time-consuming than the other segmentation methods because it required pre-segmentation, image registration and tissue classification-determination steps.

Bae, K. T.; Commean, P. K.; Brunsden, B. S.; Baumgarten, D. A.; King, B. F., Jr.; Wetzel, L. H.; Kenney, P. J.; Chapman, A. B.; Torres, V. E.; Grantham, J. J.; Guay-Woodford, L. M.; Tao, C.; Miller, J. P.; Meyers, C. M.; Bennett, W. M.

2008-03-01

198

Visual versus Computerized Analysis of Upsloping ST Segment Depression in the Exercise Electrocardiogram  

Microsoft Academic Search

A slowly upsloping ST segment depression is an abnormal, and a rapidly upsloping ST segment depression is a normal exercise ECG response. We investigated the agreement of expert physicians on the visual classification of the ST segment depression, and compared the (majority) vote with the computer-generated ST slope. A total of 206 exercise ECG leads with an amplitude of the

Markku A. Walamies; Tiit Kööbi; Liisa I. Hämäläinen; Esa A. Ahonen

1999-01-01

199

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

200

Birefringence and large mode area analysis of segmented cladding index-guiding photonic crystal fibers  

NASA Astrophysics Data System (ADS)

High birefringence and large mode area are the two paramount requirements of single-mode fibers to control polarization mode dispersion and nonlinear effects. We have investigated the birefringence, higher-order mode coupling loss of a fundamental mode (FM), and numerical aperture of index-guiding segmented cladding photonic crystal fibers in continuation to our previous analysis of the design for FM confinement and V parameter. High birefringence on the order of 10-4 to 10-3 over the near-infrared to short-wavelength infrared (0.75 to 2.3 ?m) spectral range has been obtained. The finite difference time domain method has been used for simulation. The center defect in the lattice forms the core and the remaining part represents the cladding. With phosphate glass (ngl=1.56) as a base material, cladding consists of different segments formed by varying the air hole diameter resulting in strong form birefringence and reduced numerical aperture which leads to a large mode area. We inferred a relation between fiber symmetry and birefringence by varying the duty cycle of the designs. A significant reduction in beat lengths shows reduced power losses in the FM due to higher-order mode coupling.

Kanungo, Vinay; Janyani, Vijay; Salim, Mohammad

2015-02-01

201

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

202

Segmental hair analysis after a single dose of zolpidem: comparison with a previous study.  

PubMed

Hair is a useful aid and sometimes even the only matrix in the analytical strategy in drug-facilitated crime (DFC) investigations. In this novel study, segmental hair analysis was performed after a single 10 mg dose of zolpidem was given to 20 Chinese volunteers. Hair was collected 1 month after administration and was analyzed using ultra-high-pressure liquid chromatography/electrospray ionization tandem mass spectrometry. Zolpidem concentrations were found to be in the range of 135.0-554.6 pg/mg in the proximal 0-2 cm segments. These results were markedly different from those reported by Villain et al., who used volunteers administered equal doses of zolpidem. The analytical method used, as well as the volunteers' hair color, inter-individual variations such as metabolic capacity, hair growth rate, drug incorporation rates, physical state of the hair, age, gender, body weight, etc. and diffusion from sweat or other secretions are all factors that should be considered when interpreting the DFC results. PMID:23657838

Cui, Xiaopei; Xiang, Ping; Zhang, Jingshuo; Shi, Yan; Shen, Baohua; Shen, Min

2013-01-01

203

GGO nodule volume-preserving nonrigid lung registration using GLCM texture analysis.  

PubMed

In lung cancer screening, benign and malignant nodules can be classified through nodule growth assessment by the registration and, then, subtraction between follow-up computed tomography scans. During the registration, the volume of nodule regions in the floating image should be preserved, whereas the volume of other regions in the floating image should be aligned to that in the reference image. However, ground glass opacity (GGO) nodules are very elusive to automatically segment due to their inhomogeneous interior. In other words, it is difficult to automatically define the volume-preserving regions of GGO nodules. In this paper, we propose an accurate and fast nonrigid registration method. It applies the volume-preserving constraint to candidate regions of GGO nodules, which are automatically detected by gray-level cooccurrence matrix (GLCM) texture analysis. Considering that GGO nodules can be characterized by their inner inhomogeneity and high intensity, we identify the candidate regions of GGO nodules based on the homogeneity values calculated by the GLCM and the intensity values. Furthermore, we accelerate our nonrigid registration by using Compute Unified Device Architecture (CUDA). In the nonrigid registration process, the computationally expensive procedures of the floating-image transformation and the cost-function calculation are accelerated by using CUDA. The experimental results demonstrated that our method almost perfectly preserves the volume of GGO nodules in the floating image as well as effectively aligns the lung between the reference and floating images. Regarding the computational performance, our CUDA-based method delivers about 20× faster registration than the conventional method. Our method can be successfully applied to a GGO nodule follow-up study and can be extended to the volume-preserving registration and subtraction of specific diseases in other organs (e.g., liver cancer). PMID:21775252

Park, Seongjin; Kim, Bohyoung; Lee, Jeongjin; Goo, Jin Mo; Shin, Yeong-Gil

2011-10-01

204

Introduction to Psychology and Leadership. Part Two; Individual Behavior. Segments I, II, III, IV, & V, Volume II-B.  

ERIC Educational Resources Information Center

The second volume of the introduction to psychology and leadership course (see the final reports which summarize the development projects, EM 010 418, EM 010 419, and EM 010 484) concentrates on the psychology of individual behavior and is divided into three separate documents. Like Volume One (EM 010 420), it is also a self-instructional,…

Westinghouse Learning Corp., Annapolis, MD.

205

Introduction to Psychology and Leadership. Part Five; Military Management. Segments VII, VIII, IX & X, Volume V-C.  

ERIC Educational Resources Information Center

The fifth volume of the introduction to psychology and leadership course (see the final reports which summarize the development project, EM 010 418, EM 010 419, and EM 010 484) concentrates on military management and is presented in three separate documents. Like Volume One (EM 010 420), this document is a self-instructional syndactic text with…

Westinghouse Learning Corp., Annapolis, MD.

206

Screening Analysis : Volume 1, Description and Conclusions.  

SciTech Connect

The SOR consists of three analytical phases leading to a Draft EIS. The first phase Pilot Analysis, was performed for the purpose of testing the decision analysis methodology being used in the SOR. The Pilot Analysis is described later in this chapter. The second phase, Screening Analysis, examines all possible operating alternatives using a simplified analytical approach. It is described in detail in this and the next chapter. This document also presents the results of screening. The final phase, Full-Scale Analysis, will be documented in the Draft EIS and is intended to evaluate comprehensively the few, best alternatives arising from the screening analysis. The purpose of screening is to analyze a wide variety of differing ways of operating the Columbia River system to test the reaction of the system to change. The many alternatives considered reflect the range of needs and requirements of the various river users and interests in the Columbia River Basin. While some of the alternatives might be viewed as extreme, the information gained from the analysis is useful in highlighting issues and conflicts in meeting operating objectives. Screening is also intended to develop a broad technical basis for evaluation including regional experts and to begin developing an evaluation capability for each river use that will support full-scale analysis. Finally, screening provides a logical method for examining all possible options and reaching a decision on a few alternatives worthy of full-scale analysis. An organizational structure was developed and staffed to manage and execute the SOR, specifically during the screening phase and the upcoming full-scale analysis phase. The organization involves ten technical work groups, each representing a particular river use. Several other groups exist to oversee or support the efforts of the work groups.

Bonneville Power Administration; Corps of Engineers; Bureau of Reclamation

1992-08-01

207

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

208

Improved helicopter aeromechanical stability analysis using segmented constrained layer damping and hybrid optimization  

NASA Astrophysics Data System (ADS)

Aeromechanical stability plays a critical role in helicopter design and lead-lag damping is crucial to this design. In this paper, the use of segmented constrained damping layer (SCL) treatment and composite tailoring is investigated for improved rotor aeromechanical stability using formal optimization technique. The principal load-carrying member in the rotor blade is represented by a composite box beam, of arbitrary thickness, with surface bonded SCLs. A comprehensive theory is used to model the smart box beam. A ground resonance analysis model and an air resonance analysis model are implemented in the rotor blade built around the composite box beam with SCLs. The Pitt-Peters dynamic inflow model is used in air resonance analysis under hover condition. A hybrid optimization technique is used to investigate the optimum design of the composite box beam with surface bonded SCLs for improved damping characteristics. Parameters such as stacking sequence of the composite laminates and placement of SCLs are used as design variables. Detailed numerical studies are presented for aeromechanical stability analysis. It is shown that optimum blade design yields significant increase in rotor lead-lag regressive modal damping compared to the initial system.

Liu, Qiang; Chattopadhyay, Aditi

2000-06-01

209

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

210

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

211

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

212

Swept Volume Parameterization for Isogeometric Analysis  

E-print Network

of interesting free-form shapes, such as blades of turbines and propellers, ship hulls or wings of airplanes for performing numerical simulations. The first part of this paper presents a variational framework. The second part of the paper reports the results of isogeometric analysis which were obtained with the help

Jüttler, Bert

213

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

214

Vessel segmentation in 3D spectral OCT scans of the retina  

NASA Astrophysics Data System (ADS)

The latest generation of spectral optical coherence tomography (OCT) scanners is able to image 3D cross-sectional volumes of the retina at a high resolution and high speed. These scans offer a detailed view of the structure of the retina. Automated segmentation of the vessels in these volumes may lead to more objective diagnosis of retinal vascular disease including hypertensive retinopathy, retinopathy of prematurity. Additionally, vessel segmentation can allow color fundus images to be registered to these 3D volumes, possibly leading to a better understanding of the structure and localization of retinal structures and lesions. In this paper we present a method for automatically segmenting the vessels in a 3D OCT volume. First, the retina is automatically segmented into multiple layers, using simultaneous segmentation of their boundary surfaces in 3D. Next, a 2D projection of the vessels is produced by only using information from certain segmented layers. Finally, a supervised, pixel classification based vessel segmentation approach is applied to the projection image. We compared the influence of two methods for the projection on the performance of the vessel segmentation on 10 optic nerve head centered 3D OCT scans. The method was trained on 5 independent scans. Using ROC analysis, our proposed vessel segmentation system obtains an area under the curve of 0.970 when compared with the segmentation of a human observer.

Niemeijer, Meindert; Garvin, Mona K.; van Ginneken, Bram; Sonka, Milan; Abràmoff, Michael D.

2008-03-01

215

Segmentation with Area Constraints  

PubMed Central

Image segmentation approaches typically incorporate weak regularity conditions such as boundary length or curvature terms, or use shape information. High-level information such as a desired area or volume, or a particular topology are only implicitly specified. In this paper we develop a segmentation method with explicit bounds on the segmented area. Area constraints allow for the soft selection of meaningful solutions, and can counteract the shrinking bias of length-based regularization. We analyze the intrinsic problems of convex relaxations proposed in the literature for segmentation with size constraints. Hence, we formulate the area-constrained segmentation task as a mixed integer program, propose a branch and bound method for exact minimization, and use convex relaxations to obtain the required lower energy bounds on candidate solutions. We also provide a numerical scheme to solve the convex subproblems. We demonstrate the method for segmentations of vesicles from electron tomography images. PMID:23084504

Niethammer, Marc; Zach, Christopher

2012-01-01

216

A Comparison of Two Commercial Volumetry Software Programs in the Analysis of Pulmonary Ground-Glass Nodules: Segmentation Capability and Measurement Accuracy  

PubMed Central

Objective To compare the segmentation capability of the 2 currently available commercial volumetry software programs with specific segmentation algorithms for pulmonary ground-glass nodules (GGNs) and to assess their measurement accuracy. Materials and Methods In this study, 55 patients with 66 GGNs underwent unenhanced low-dose CT. GGN segmentation was performed by using 2 volumetry software programs (LungCARE, Siemens Healthcare; LungVCAR, GE Healthcare). Successful nodule segmentation was assessed visually and morphologic features of GGNs were evaluated to determine factors affecting segmentation by both types of software. In addition, the measurement accuracy of the software programs was investigated by using an anthropomorphic chest phantom containing simulated GGNs. Results The successful nodule segmentation rate was significantly higher in LungCARE (90.9%) than in LungVCAR (72.7%) (p = 0.012). Vascular attachment was a negatively influencing morphologic feature of nodule segmentation for both software programs. As for measurement accuracy, mean relative volume measurement errors in nodules ? 10 mm were 14.89% with LungCARE and 19.96% with LungVCAR. The mean relative attenuation measurement errors in nodules ? 10 mm were 3.03% with LungCARE and 5.12% with LungVCAR. Conclusion LungCARE shows significantly higher segmentation success rates than LungVCAR. Measurement accuracy of volume and attenuation of GGNs is acceptable in GGNs ? 10 mm by both software programs. PMID:23901328

Kim, Hyungjin; Lee, Sang Min; Lee, Hyun-Ju; Goo, Jin Mo

2013-01-01

217

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

218

ANALYSIS OF GRADIENT FLOW OF A REGULARIZED MUMFORD-SHAH FUNCTIONAL FOR IMAGE SEGMENTATION AND IMAGE INPAINTING  

E-print Network

by Esedoglu and Shen [20] for image inpainting. It is shown that the gradient flow with L2 Ã? L initial dataANALYSIS OF GRADIENT FLOW OF A REGULARIZED MUMFORD-SHAH FUNCTIONAL FOR IMAGE SEGMENTATION AND IMAGE INPAINTING XIAOBING FENG AND ANDREAS PROHL Abstract. This paper studies the gradient flow of a regularized

219

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.

220

Bivariate segmentation of SNP-array data for allele-specific copy number analysis in tumour samples  

PubMed Central

Background SNP arrays output two signals that reflect the total genomic copy number (LRR) and the allelic ratio (BAF), which in combination allow the characterisation of allele-specific copy numbers (ASCNs). While methods based on hidden Markov models (HMMs) have been extended from array comparative genomic hybridisation (aCGH) to jointly handle the two signals, only one method based on change-point detection, ASCAT, performs bivariate segmentation. Results In the present work, we introduce a generic framework for bivariate segmentation of SNP array data for ASCN analysis. For the matter, we discuss the characteristics of the typically applied BAF transformation and how they affect segmentation, introduce concepts of multivariate time series analysis that are of concern in this field and discuss the appropriate formulation of the problem. The framework is implemented in a method named CnaStruct, the bivariate form of the structural change model (SCM), which has been successfully applied to transcriptome mapping and aCGH. Conclusions On a comprehensive synthetic dataset, we show that CnaStruct outperforms the segmentation of existing ASCN analysis methods. Furthermore, CnaStruct can be integrated into the workflows of several ASCN analysis tools in order to improve their performance, specially on tumour samples highly contaminated by normal cells. PMID:23497144

2013-01-01

221

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

222

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

223

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

224

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

225

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

226

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

227

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

228

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

229

Incorporation of texture-based features in optimal graph-theoretic approach with application to the 3D segmentation of intraretinal surfaces in SD-OCT volumes  

NASA Astrophysics Data System (ADS)

While efficient graph-theoretic approaches exist for the optimal (with respect to a cost function) and simultaneous segmentation of multiple surfaces within volumetric medical images, the appropriate design of cost functions remains an important challenge. Previously proposed methods have used simple cost functions or optimized a combination of the same, but little has been done to design cost functions using learned features from a training set, in a less biased fashion. Here, we present a method to design cost functions for the simultaneous segmentation of multiple surfaces using the graph-theoretic approach. Classified texture features were used to create probability maps, which were incorporated into the graph-search approach. The efficiency of such an approach was tested on 10 optic nerve head centered optical coherence tomography (OCT) volumes obtained from 10 subjects that presented with glaucoma. The mean unsigned border position error was computed with respect to the average of manual tracings from two independent observers and compared to our previously reported results. A significant improvement was noted in the overall means which reduced from 9.25 +/- 4.03?m to 6.73 +/- 2.45?m (p < 0.01) and is also comparable with the inter-observer variability of 8.85 +/- 3.85?m.

Antony, Bhavna J.; Abràmoff, Michael D.; Sonka, Milan; Kwon, Young H.; Garvin, Mona K.

2012-02-01

230

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

231

Dual-Modality PET-CT Visualization using Real-Time Volume Rendering and Image Fusion with Interactive 3D Segmentation of Anatomical Structures.  

PubMed

Recent advances in medical imaging have resulted in the introduction of dual-modality scanners which can simultaneously acquire two independent imaging modalities, such as positron emission tomography (PET) and computed tomography (CT) image data in a single session. These multi-dimensional PET-CT data contain both the functional and anatomical information of the human body, thus, providing the ability to identify anatomical structures of interest and then overlaying the result onto the corresponding functional structure, as an example. The utilization of the combined functional and anatomical information has been proven to be an effective approach in diagnosis and interpretation of certain medical conditions. However, the increase in image dimensions has not been accompanied with new visualization techniques, with the use of two-dimensional (2D) display being the norm. In this study, we propose a new approach to three-dimensional (3D) visualization of dual-modality PET-CT data in order to complement the 2D visualization and potentially improve medical diagnosis and interpretation. We have design and implemented a prototype visualization technique using real-time volume rendering and image fusion running on a commodity graphics card. We further propose the application of interactive segmentation of 3D anatomical structures from CT data which can be used to identify the corresponding functional structure in volume visualization. PMID:17282264

Kim, Jinman; Cai, Weidong; Feng, Dagan

2005-01-01

232

Impact of intracoronary bone marrow cell therapy on left ventricular function in the setting of ST-segment elevation myocardial infarction: a collaborative meta-analysis  

PubMed Central

Aims The objective of the present analysis was to systematically examine the effect of intracoronary bone marrow cell (BMC) therapy on left ventricular (LV) function after ST-segment elevation myocardial infarction in various subgroups of patients by performing a collaborative meta-analysis of randomized controlled trials. Methods and results We identified all randomized controlled trials comparing intracoronary BMC infusion as treatment for ST-segment elevation myocardial infarction. We contacted the principal investigator for each participating trial to provide summary data with regard to different pre-specified subgroups [age, diabetes mellitus, time from symptoms to percutaneous coronary intervention, infarct-related artery, LV end-diastolic volume index (EDVI), LV ejection fraction (EF), infarct size, presence of microvascular obstruction, timing of cell infusion, and injected cell number] and three different endpoints [change in LVEF, LVEDVI, and LV end-systolic volume index (ESVI)]. Data from 16 studies were combined including 1641 patients (984 cell therapy, 657 controls). The absolute improvement in LVEF was greater among BMC-treated patients compared with controls: [2.55% increase, 95% confidence interval (CI) 1.83–3.26, P < 0.001]. Cell therapy significantly reduced LVEDVI and LVESVI (?3.17 mL/m², 95% CI: ?4.86 to ?1.47, P < 0.001; ?2.60 mL/m², 95% CI ?3.84 to ?1.35, P < 0.001, respectively). Treatment benefit in terms of LVEF improvement was more pronounced in younger patients (age <55, 3.38%, 95% CI: 2.36–4.39) compared with older patients (age ?55 years, 1.77%, 95% CI: 0.80–2.74, P = 0.03). This heterogeneity in treatment effect was also observed with respect to the reduction in LVEDVI and LVESVI. Moreover, patients with baseline LVEF <40% derived more benefit from intracoronary BMC therapy. LVEF improvement was 5.30%, 95% CI: 4.27–6.33 in patients with LVEF <40% compared with 1.45%, 95% CI: 0.60 to 2.31 in LVEF ?40%, P < 0.001. No clear interaction was observed between other subgroups and outcomes. Conclusion Intracoronary BMC infusion is associated with improvement of LV function and remodelling in patients after ST-segment elevation myocardial infarction. Younger patients and patients with a more severely depressed LVEF at baseline derived most benefit from this adjunctive therapy. PMID:24026778

Delewi, Ronak; Hirsch, Alexander; Tijssen, Jan G.; Schächinger, Volker; Wojakowski, Wojciech; Roncalli, Jérôme; Aakhus, Svend; Erbs, Sandra; Assmus, Birgit; Tendera, Michal; Goekmen Turan, R.; Corti, Roberto; Henry, Tim; Lemarchand, Patricia; Lunde, Ketil; Cao, Feng; Huikuri, Heikki V.; Sürder, Daniel; Simari, Robert D.; Janssens, Stefan; Wollert, Kai C.; Plewka, Michal; Grajek, Stefan; Traverse, Jay H.; Zijlstra, Felix; Piek, Jan J.

2014-01-01

233

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

234

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

235

An Intergrated Data Mining and Survival Analysis Model for Customer Segmentation  

Microsoft Academic Search

\\u000a More and more literatures have researched the application of data mining technology in customer segmentation, and achieved\\u000a sound effects. One of the key purposes of customer segmentation is customer retention. But the application of single data\\u000a mining technology mentioned in previous literatures is unable to identify customer churn trend for adopting different actions\\u000a on customer retention. This paper focus on

Guozheng Zhang; Yun Chen

2007-01-01

236

Elementary forms for land surface segmentation: The theoretical basis of terrain analysis and geomorphological mapping  

NASA Astrophysics Data System (ADS)

Land surface morphology is fundamental to geomorphological mapping and many GIS applications. Review and comparison of various approaches to segmentation of the land surface reveals common features, and permits development of a broad theoretical basis for segmentation and for characterization of segments and their boundaries. Within the context of defining landform units that maximise internal homogeneity and external differences, this paper introduces the concept of elementary forms (segments, units) defined by constant values of fundamental morphometric properties and limited by discontinuities of the properties. The basic system of form-defining properties represents altitude and its derivatives, constant values of which provide elementary forms with various types of homogeneity. Every geometric type of elementary form can be characterized by a defining function, which is a specific case of the general polynomial fitted function. Various types of boundary discontinuity and their connections and transformations into other types of morphological unit boundaries are analysed. The wealth of types of elementary forms and their boundaries is potentially unbounded and thus is sufficient to cover the real variety of landforms. Elementary forms in the basic set proposed here have clear potential for genetic and dynamic interpretation. A brief worked example documents the possibility of analytical computation of various models of ideal elementary forms for particular segments of landform. Ideal elementary forms can be considered as attractors, to which the affinity of surface segments can be measured by multivariate statistical methods. The use of the concept of elementary forms in landscape segmentation is promising and it could be adapted for elementary segmentation of various other spatial fields.

Minár, Jozef; Evans, Ian S.

2008-03-01

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

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

239

Fiber composite analysis and design. Volume 2: Structures  

SciTech Connect

Recent years have witnessed a significant increase in the understanding and utilization of fibrous composite materials. There has also been a much larger increase in the amount of published literature in this field. This book builds upon existing literature to present a review of the available capability for composite structural design and analysis. The aim is to provide guidance for one who seeks to become familiar with the tools required for designing with fibrous composites. Thus, the book identifies the key concepts associated with the use of these unique materials. This second volume addresses the design and analysis of structural configurations for the practical and efficient utilization of fiber composite materials.

Rosen, B.W.

1998-09-01

240

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

241

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

PubMed Central

Abstract. 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. PMID:23942632

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

2013-01-01

242

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

PubMed

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. PMID:23942632

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

2013-08-01

243

Biomechanical Analysis of Fusion Segment Rigidity Upon Stress at Both the Fusion and Adjacent Segments: A Comparison between Unilateral and Bilateral Pedicle Screw Fixation  

PubMed Central

Purpose The purpose of this study was to investigate the effects of unilateral pedicle screw fixation on the fusion segment and the superior adjacent segment after one segment lumbar fusion using validated finite element models. Materials and Methods Four L3-4 fusion models were simulated according to the extent of decompression and the method of pedicle screws fixation in L3-4 lumbar fusion. These models included hemi-laminectomy with bilateral pedicle screw fixation in the L3-4 segment (BF-HL model), total laminectomy with bilateral pedicle screw fixation (BF-TL model), hemi-laminectomy with unilateral pedicle screw fixation (UF-HL model), and total laminectomy with unilateral pedicle screw fixation (UF-TL model). In each scenario, intradiscal pressures, annulus stress, and range of motion at the L2-3 and L3-4 segments were analyzed under flexion, extension, lateral bending, and torsional moments. Results Under four pure moments, the unilateral fixation leads to a reduction in increment of range of motion at the adjacent segment, but larger motions were noted at the fusion segment (L3-4) in the unilateral fixation (UF-HL and UF-TL) models when compared to bilateral fixation. The maximal von Mises stress showed similar patterns to range of motion at both superior adjacent L2-3 segments and fusion segment. Conclusion The current study suggests that unilateral pedicle screw fixation seems to be unable to afford sufficient biomechanical stability in case of bilateral total laminectomy. Conversely, in the case of hemi-laminectomy, unilateral fixation could be an alternative option, which also has potential benefit to reduce the stress of the adjacent segment. PMID:25048501

Kim, Ho-Joong; Kang, Kyoung-Tak; Chang, Bong-Soon; Lee, Choon-Ki; Kim, Jang-Woo

2014-01-01

244

Wireless capsule endoscopy video segmentation using an unsupervised learning approach based on probabilistic latent semantic analysis with scale invariant features.  

PubMed

Since wireless capsule endoscopy (WCE) is a novel technology for recording the videos of the digestive tract of a patient, the problem of segmenting the WCE video of the digestive tract into subvideos corresponding to the entrance, stomach, small intestine, and large intestine regions is not well addressed in the literature. A selected few papers addressing this problem follow supervised leaning approaches that presume availability of a large database of correctly labeled training samples. Considering the difficulties in procuring sizable WCE training data sets needed for achieving high classification accuracy, we introduce in this paper an unsupervised learning approach that employs Scale Invariant Feature Transform (SIFT) for extraction of local image features and the probabilistic latent semantic analysis (pLSA) model used in the linguistic content analysis for data clustering. Results of experimentation indicate that this method compares well in classification accuracy with the state-of-the-art supervised classification approaches to WCE video segmentation. PMID:22010158

Shen, Yao; Guturu, Parthasarathy Partha; Buckles, Bill P

2012-01-01

245

Heart Rate Variability Analysis of Ischemic and Heart Rate Related ST-segment Deviation Episodes Based on Time-frequency Method  

Microsoft Academic Search

ST-segment deviation is the routine method for the diagnosis of coronary heart diseases. However, other phenomena, such as heart rate changes and a posture change can cause similar manifestations in the ST segment, lowing the sensitivity and specificity of the detection. In this study, a different method, based on time-frequency analysis of heart rate variability, was proposed to evaluate the

Wang Xing; Xu Liang; Sun Zhongwei; Yang Zibin; Peng Yi

2007-01-01

246

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

247

Analysis of a genomic segment of white spot syndrome virus of shrimp containing ribonucleotide reductase genes and repeat regions  

Microsoft Academic Search

White spot syndrome is a worldwide disease of penaeid shrimp. The disease agent is a bacilliform, enveloped virus, white spot syndrome virus (WSSV), with a double-stranded DNA genome that probably contains well over 200 kb. Analysis of a 12?3 kb segment of WSSV DNA revealed eight open reading frames (ORFs), including the genes for the large (RR1) and small (RR2)

Hulten van M. C. W; Meng-feng Tsai; Christel A. Schipper; Chu-fang Lo; Guang-hsiung Kou; Just M. Vlak

2000-01-01

248

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

249

Global Warming’s Six Americas: An Audience Segmentation Analysis (Invited)  

NASA Astrophysics Data System (ADS)

One of the first rules of effective communication is to “know thy audience.” People have different psychological, cultural and political reasons for acting - or not acting - to reduce greenhouse gas emissions, and climate change educators can increase their impact by taking these differences into account. In this presentation we will describe six unique audience segments within the American public that each responds to the issue in its own distinct way, and we will discuss methods of engaging each. The six audiences were identified using a nationally representative survey of American adults conducted in the fall of 2008 (N=2,164). In two waves of online data collection, the public’s climate change beliefs, attitudes, risk perceptions, values, policy preferences, conservation, and energy-efficiency behaviors were assessed. The data were subjected to latent class analysis, yielding six groups distinguishable on all the above dimensions. The Alarmed (18%) are fully convinced of the reality and seriousness of climate change and are already taking individual, consumer, and political action to address it. The Concerned (33%) - the largest of the Six Americas - are also convinced that global warming is happening and a serious problem, but have not yet engaged with the issue personally. Three other Americas - the Cautious (19%), the Disengaged (12%) and the Doubtful (11%) - represent different stages of understanding and acceptance of the problem, and none are actively involved. The final America - the Dismissive (7%) - are very sure it is not happening and are actively involved as opponents of a national effort to reduce greenhouse gas emissions. Mitigating climate change will require a diversity of messages, messengers and methods that take into account these differences within the American public. The findings from this research can serve as guideposts for educators on the optimal choices for reaching and influencing target groups with varied informational needs, values and beliefs.

Roser-Renouf, C.; Maibach, E.; Leiserowitz, A.

2009-12-01

250

Parallel runway requirement analysis study. Volume 2: Simulation manual  

NASA Technical Reports Server (NTRS)

This document is a user manual for operating the PLAND_BLUNDER (PLB) simulation program. This simulation is based on two aircraft approaching parallel runways independently and using parallel Instrument Landing System (ILS) equipment during Instrument Meteorological Conditions (IMC). If an aircraft should deviate from its assigned localizer course toward the opposite runway, this constitutes a blunder which could endanger the aircraft on the adjacent path. The worst case scenario would be if the blundering aircraft were unable to recover and continue toward the adjacent runway. PLAND_BLUNDER is a Monte Carlo-type simulation which employs the events and aircraft positioning during such a blunder situation. The model simulates two aircraft performing parallel ILS approaches using Instrument Flight Rules (IFR) or visual procedures. PLB uses a simple movement model and control law in three dimensions (X, Y, Z). The parameters of the simulation inputs and outputs are defined in this document along with a sample of the statistical analysis. This document is the second volume of a two volume set. Volume 1 is a description of the application of the PLB to the analysis of close parallel runway operations.

Ebrahimi, Yaghoob S.; Chun, Ken S.

1993-01-01

251

Comparative analysis of operational forecasts versus actual weather conditions in airline flight planning, volume 4  

NASA Technical Reports Server (NTRS)

The impact of more timely and accurate weather data on airline flight planning with the emphasis on fuel savings is studied. This volume of the report discusses the results of Task 4 of the four major tasks included in the study. Task 4 uses flight plan segment wind and temperature differences as indicators of dates and geographic areas for which significant forecast errors may have occurred. An in-depth analysis is then conducted for the days identified. The analysis show that significant errors occur in the operational forecast on 15 of the 33 arbitrarily selected days included in the study. Wind speeds in an area of maximum winds are underestimated by at least 20 to 25 kts. on 14 of these days. The analysis also show that there is a tendency to repeat the same forecast errors from prog to prog. Also, some perceived forecast errors from the flight plan comparisons could not be verified by visual inspection of the corresponding National Meteorological Center forecast and analyses charts, and it is likely that they are the result of weather data interpolation techniques or some other data processing procedure in the airlines' flight planning systems.

Keitz, J. F.

1982-01-01

252

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

253

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

254

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

255

Liver segmentation in contrast enhanced CT data using graph cuts and interactive 3D segmentation refinement methods  

SciTech Connect

Purpose: Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. Methods: A graph cuts segmentation method was combined with a three-dimensional virtual reality based segmentation refinement approach. The developed interactive segmentation system allowed the user to manipulate volume chunks and/or surfaces instead of 2D contours in cross-sectional images (i.e, slice-by-slice). The method was evaluated on twenty routinely acquired portal-phase contrast enhanced multislice computed tomography (CT) data sets. An independent reference was generated by utilizing a currently clinically utilized slice-by-slice segmentation method. After 1 h of introduction to the developed segmentation system, three experts were asked to segment all twenty data sets with the proposed method. Results: Compared to the independent standard, the relative volumetric segmentation overlap error averaged over all three experts and all twenty data sets was 3.74%. Liver segmentation required on average 16 min of user interaction per case. The calculated relative volumetric overlap errors were not found to be significantly different [analysis of variance (ANOVA) test, p = 0.82] between experts who utilized the proposed 3D system. In contrast, the time required by each expert for segmentation was found to be significantly different (ANOVA test, p = 0.0009). Major differences between generated segmentations and independent references were observed in areas were vessels enter or leave the liver and no accepted criteria for defining liver boundaries exist. In comparison, slice-by-slice based generation of the independent standard utilizing a live wire tool took 70.1 min on average. A standard 2D segmentation refinement approach applied to all twenty data sets required on average 38.2 min of user interaction and resulted in statistically not significantly different segmentation error indices (ANOVA test, significance level of 0.05). Conclusions: All three experts were able to produce liver segmentations with low error rates. User interaction time savings of up to 71% compared to a 2D refinement approach demonstrate the utility and potential of our approach. The system offers a range of different tools to manipulate segmentation results, and some users might benefit from a longer learning phase to develop efficient segmentation refinement strategies. The presented approach represents a generally applicable segmentation approach that can be applied to many medical image segmentation problems.

Beichel, Reinhard; Bornik, Alexander; Bauer, Christian; Sorantin, Erich [Departments of Electrical and Computer Engineering and Internal Medicine, Iowa Institute for Biomedical Imaging, University of Iowa, Iowa City, Iowa 52242 (United States); Institute for Computer Graphics and Vision, Graz University of Technology, Inffeldgasse 16, A-8010 Graz (Austria); Department of Electrical and Computer Engineering, Iowa Institute for Biomedical Imaging, University of Iowa, Iowa City, Iowa 52242 (United States); Department of Radiology, Medical University Graz, Auenbruggerplatz 34, A-8010 Graz (Austria)

2012-03-15

256

Liver segmentation in contrast enhanced CT data using graph cuts and interactive 3D segmentation refinement methods  

PubMed Central

Purpose: Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. Methods: A graph cuts segmentation method was combined with a three-dimensional virtual reality based segmentation refinement approach. The developed interactive segmentation system allowed the user to manipulate volume chunks and/or surfaces instead of 2D contours in cross-sectional images (i.e, slice-by-slice). The method was evaluated on twenty routinely acquired portal-phase contrast enhanced multislice computed tomography (CT) data sets. An independent reference was generated by utilizing a currently clinically utilized slice-by-slice segmentation method. After 1 h of introduction to the developed segmentation system, three experts were asked to segment all twenty data sets with the proposed method. Results: Compared to the independent standard, the relative volumetric segmentation overlap error averaged over all three experts and all twenty data sets was 3.74%. Liver segmentation required on average 16 min of user interaction per case. The calculated relative volumetric overlap errors were not found to be significantly different [analysis of variance (ANOVA) test,p?=?0.82] between experts who utilized the proposed 3D system. In contrast, the time required by each expert for segmentation was found to be significantly different (ANOVA test, p?=?0.0009). Major differences between generated segmentations and independent references were observed in areas were vessels enter or leave the liver and no accepted criteria for defining liver boundaries exist. In comparison, slice-by-slice based generation of the independent standard utilizing a live wire tool took 70.1 min on average. A standard 2D segmentation refinement approach applied to all twenty data sets required on average 38.2 min of user interaction and resulted in statistically not significantly different segmentation error indices (ANOVA test, significance level of 0.05). Conclusions: All three experts were able to produce liver segmentations with low error rates. User interaction time savings of up to 71% compared to a 2D refinement approach demonstrate the utility and potential of our approach. The system offers a range of different tools to manipulate segmentation results, and some users might benefit from a longer learning phase to develop efficient segmentation refinement strategies. The presented approach represents a generally applicable segmentation approach that can be applied to many medical image segmentation problems. PMID:22380370

Beichel, Reinhard; Bornik, Alexander; Bauer, Christian; Sorantin, Erich

2012-01-01

257

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

PubMed Central

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

2015-01-01

258

Analysis of volume holographic storage allowing large-angle illumination  

NASA Astrophysics Data System (ADS)

Advanced technological developments have stimulated renewed interest in volume holography for applications such as information storage and wavelength multiplexing for communications and laser beam shaping. In these and many other applications, the information-carrying wave fronts usually possess narrow spatial-frequency bands, although they may propagate at large angles with respect to each other or a preferred optical axis. Conventional analytic methods are not capable of properly analyzing the optical architectures involved. For mitigation of the analytic difficulties, a novel approximation is introduced to treat narrow spatial-frequency band wave fronts propagating at large angles. This approximation is incorporated into the analysis of volume holography based on a plane-wave decomposition and Fourier analysis. As a result of the analysis, the recently introduced generalized Bragg selectivity is rederived for this more general case and is shown to provide enhanced performance for the above indicated applications. The power of the new theoretical description is demonstrated with the help of specific examples and computer simulations. The simulations reveal some interesting effects, such as coherent motion blur, that were predicted in an earlier publication.

Shamir, Joseph

2005-05-01

259

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

260

User's operating procedures. Volume 2: Scout project financial analysis program  

NASA Technical Reports Server (NTRS)

A review is presented of the user's operating procedures for the Scout Project Automatic Data system, called SPADS. SPADS is the result of the past seven years of software development on a Prime mini-computer located at the Scout Project Office, NASA Langley Research Center, Hampton, Virginia. SPADS was developed as a single entry, multiple cross-reference data management and information retrieval system for the automation of Project office tasks, including engineering, financial, managerial, and clerical support. This volume, two (2) of three (3), provides the instructions to operate the Scout Project Financial Analysis program in data retrieval and file maintenance via the user friendly menu drivers.

Harris, C. G.; Haris, D. K.

1985-01-01

261

A three-dimensional, six-segment chain analysis of forceful overarm throwing  

Microsoft Academic Search

A three-dimensional, six-segment model was applied to the pitching motion of three professional pitchers to analyze the kinematics and kinetics of the hips, upper trunk, humerus and forearm plus hand of both the upper limbs. Subjects were filmed at 250 frames per second. An inverse dynamics approach and angular momentum principle with respect to the proximal endpoint of a rigid

Di-An Hong; Tak K Cheung; Elizabeth M Roberts

2001-01-01

262

Analysis of bleb morphology after trabeculectomy with Visante anterior segment optical coherence tomography  

Microsoft Academic Search

Background: To describe the use of anterior segment optical coherence tomography (OCT) in imaging intrableb morphology after trabeculectomy.Methods: 14 post-trabeculectomy eyes from 11 primary open angle glaucoma and 3 primary angle closure glaucoma subjects were studied. The blebs were classified with reference to slit lamp morphology and bleb function. They included diffuse filtering (n = 7), cystic (n = 2),

Christopher Kai-shun Leung; Doris Wai-fong Yick; Yolanda Yuen-ying Kwong; Felix Chi-hong Li; Dexter Yu-lung Leung; Shaheeda Mohamed; Clement Chee-yung Tham; Chi Chung-chai; Dennis Shun-Chiu Lam

2007-01-01

263

Analysis of gradient flow of a regularized Mumford-Shahfunctional for image segmentation and image inpainting  

Microsoft Academic Search

This paper studies the gradient flow of a regularized Mumford-Shah functional proposed by Ambrosio and Tortorelli (1990, 1992) for image segmentation, and adopted by Esedoglu and Shen (2002) for image inpainting. It is shown that the gradient flow with L2×L? initial data possesses a global weak solution, and it has a unique global in time strong solution, which has at

Xiaobing Feng; Andreas Prohl

2004-01-01

264

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

265

Segmentation of hyper-pigmented spots in human skin using automated cluster analysis  

NASA Astrophysics Data System (ADS)

The appearance and color distribution of skin are important characteristics that affect the human perception of health and vitality. Dermatologists and other skin researchers often use color and appearance to diagnose skin conditions and monitor the efficacy of procedures and treatments. Historically, most skin color and chromophore measurements have been performed using reflectance spectrometers and colorimeters. These devices acquire a single measurement over an integrated area defined by an aperture, and are therefore poorly suited to measure the color of pigmented lesions or other blemishes. Measurements of spots smaller than the aperture will be washed out with background, and spots that are larger may not be adequately sampled unless the blemish is homogenous. Recently, multispectral imaging devices have become available for skin imaging. These devices are designed to image regions of skin and provide information about the levels of endogenous chromophores present in the image field of view. This data is presented as four images at each measurement site including RGB color, melanin, collagen, and blood images. We developed a robust segmentation technique that can segment skin blemishes in these images and provide more precise values of melanin, blood, and collagen by only analyzing the segmented region of interest. Results from hundreds of skin images show this to be a robust automated segmentation technique over a range of skin tones and shades.

Gossage, Kirk W.; Weissman, Jesse; Velthuizen, Robert

2009-02-01

266

Bayesian analysis of cell nucleus segmentation by a Viterbi search based active contour  

Microsoft Academic Search

An image segmentation scheme is shown to be exceptionally successful through the application of high-level knowledge of the required image objects (cell nuclei). By tuning the algorithm's single parameter it is shown that the performance can be maximised for the dataset, but leads to individual failures that may require alternative choices. A second stage is introduced to process each of

Pascal Bamford; Brian Lovell

1998-01-01

267

Infants' Early Ability to Segment the Conversational Speech Signal Predicts Later Language Development: A Retrospective Analysis  

ERIC Educational Resources Information Center

Two studies examined relationships between infants' early speech processing performance and later language and cognitive outcomes. Study 1 found that performance on speech segmentation tasks before 12 months of age related to expressive vocabulary at 24 months. However, performance on other tasks was not related to 2-year vocabulary. Study 2…

Newman, Rochelle; Ratner, Nan Bernstein; Jusczyk, Ann Marie; Jusczyk, Peter W.; Dow, Kathy Ayala

2006-01-01

268

Laser Capture Microdissection-Microarray Analysis of Focal Segmental Glomerulosclerosis Glomeruli  

Microsoft Academic Search

Focal segmental glomerulosclerosis (FSGS) is a major cause of end-stage renal disease. In this report we used laser capture microdissection to purify diseased glomeruli, and microarrays to provide universal gene expression profiles. The results provide a deeper understanding of the molecular mechanisms of the disease process and suggest novel therapeutic strategies. Consistent with earlier studies, molecular markers of the differentiated

Michael R. Bennett; Kimberly A. Czech; Lois J. Arend; David P. Witte; Prasad Devarajan; S. Steven Potter

2007-01-01

269

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

270

The analysis of a segmented paraboloidal reflector with hexagonal flat sections  

Microsoft Academic Search

Segmented reflectors are an important sub-category of reflector antennas where the smooth compound curvature of the reflector is approximated by many small flat sections. The general dynamics (GD) paraboloidal truss antenna described by Fager and Garriot (1969) consists of a large number of hexagonal flats. This antenna was initially intended for space deployment, but this antenna appears to be suitable

1995-01-01

271

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

272

Sequence and phylogenetic analysis of the S1 Genome segment of turkey-origin reoviruses  

Technology Transfer Automated Retrieval System (TEKTRAN)

Based on previous reports characterizing the turkey-origin avian reovirus (TRV) sigma-B (sigma-2) major outer capsid protein gene, the TRVs may represent a new group within the fusogenic orthoreoviruses. However, no sequence data from other TRV genes or genome segments has been reported. The sigma...

273

Performance Analysis of CATR Reflector with Super Hybrid Modulated Segmented Exponential Serrated Edges  

Microsoft Academic Search

This paper presented a theoretical and numerical investigation of the Compact Antenna Test Range (CATR) equipped with Super Hybrid Modulated Segmented Exponential Serrations (SHMSES). The investigation was based on diffraction theory and, more specifically, the Fresnel diffraction formulation. The CATR provides uniform illumination within the Fresnel region to test antenna. Application of serrated edges has been shown to be a

T. Venkata Rama Krishna; P. Siddaiah; B. Prabhakara Rao

2007-01-01

274

The effect of lead selection on traditional and heart rate–adjusted ST segment analysis in the detection of coronary artery disease during exercise testing  

Microsoft Academic Search

Several methods of heart rate–adjusted ST segment (ST\\/HR) analysis have been suggested to improve the diagnostic accuracy of exercise electrocardiography in the identification of coronary artery disease compared with traditional ST segment analysis. However, no comprehensive comparison of these methods on a lead-by-lead basis in all 12 electrocardographic leads has been reported. This article compares the diagnostic performance of ST\\/HR

Jari Viik; Rami Lehtinen; Väinö Turjanmaa; Kari Niemelä; Jaakko Malmivuo

1997-01-01

275

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. PMID:25580192

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

2014-01-01

276

Treatment Response Assessment of Head and Neck Cancers on CT Using Computerized Volume Analysis  

PubMed Central

Background and Purpose Head and neck cancer can cause substantial morbidity and mortality Our aim was to evaluate the potential usefulness of a computerized system for segmenting lesions in head and neck CT scans and for estimation of volume change of head and neck malignant tumors in response to treatment. Materials and Methods CT scans from a pretreatment examination and a post 1-cycle chemotherapy examination of 34 patients with 34 head and neck primary-site cancers were collected. The computerized system was developed in our laboratory. It performs 3D segmentation on the basis of a level-set model and uses as input an approximate bounding box for the lesion of interest. The 34 tumors included tongue, tonsil, vallecula, supraglottic, epiglottic, and hard palate carcinomas. As a reference standard, 1 radiologist outlined full 3D contours for each of the 34 primary tumors for both the pre- and posttreatment scans and a second radiologist verified the contours. Results The correlation between the automatic and manual estimates for both the pre- to post-treatment volume change and the percentage volume change for the 34 primary-site tumors was 0.95, with an average error of ?2.4 ± 8.5% by automatic segmentation. There was no substantial difference and specific trend in the automatic segmentation accuracy for the different types of primary head and neck tumors, indicating that the computerized segmentation performs relatively robustly for this application. Conclusions The tumor size change in response to treatment can be accurately estimated by the computerized segmentation system relative to radiologists' manual estimations for different types of head and neck tumors. PMID:20595363

Hadjiiski, L.; Mukherji, S.K.; Gujar, S.K.; Sahiner, B.; Ibrahim, M.; Street, E.; Moyer, J.; Worden, F.P.; Chan, H.-P.

2013-01-01

277

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

278

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

279

Multi-resolution Shape Analysis via Non-Euclidean Wavelets: Applications to Mesh Segmentation and Surface Alignment Problems  

PubMed Central

The analysis of 3-D shape meshes is a fundamental problem in computer vision, graphics, and medical imaging. Frequently, the needs of the application require that our analysis take a multi-resolution view of the shape’s local and global topology, and that the solution is consistent across multiple scales. Unfortunately, the preferred mathematical construct which offers this behavior in classical image/signal processing, Wavelets, is no longer applicable in this general setting (data with non-uniform topology). In particular, the traditional definition does not allow writing out an expansion for graphs that do not correspond to the uniformly sampled lattice (e.g., images). In this paper, we adapt recent results in harmonic analysis, to derive Non-Euclidean Wavelets based algorithms for a range of shape analysis problems in vision and medical imaging. We show how descriptors derived from the dual domain representation offer native multi-resolution behavior for characterizing local/global topology around vertices. With only minor modifications, the framework yields a method for extracting interest/key points from shapes, a surprisingly simple algorithm for 3-D shape segmentation (competitive with state of the art), and a method for surface alignment (without landmarks). We give an extensive set of comparison results on a large shape segmentation benchmark and derive a uniqueness theorem for the surface alignment problem. PMID:24390194

Kim, Won Hwa; Chung, Moo K.; Singh, Vikas

2013-01-01

280

Automated subcortical segmentation using FIRST: test-retest reliability, interscanner reliability, and comparison to manual segmentation.  

PubMed

Multiple techniques exist for the automated segmentation of magnetic resonance images (MRIs). The validity of these techniques can be assessed by evaluating test-retest reliability, interscanner reliability, and consistency with manual segmentation. We evaluate these measures for the FSL/FIRST subcortical segmentation tool. We retrospectively analyzed 190 MRI scans from 87 subjects with mood or anxiety disorders and healthy volunteers scanned multiple times on different platforms (N = 56) and/or the same platform (N = 45, groups overlap), and 146 scans from subjects who underwent both high-resolution and whole brain imaging in a single session, for comparison with manual segmentation of the hippocampus. The thalamus, caudate, putamen, hippocampus, and pallidum were reliably segmented in different sessions on the same scanner (Intraclass correlation coefficient (ICC) > 0.83 scanners and diagnostic groups pooled). In these regions, the range of between platform reliabilities were lower (0.527 < ICC < 0.953), although values below 0.7 were due to systematic differences between platforms or low reliability in the hippocampus between eight- and single-channel coil platforms. Accumbens and amygdala segmentations were generally unreliable within and between scanning platforms. ICC values for hippocampal volumes between automated and manual segmentations were acceptable (ICC > 0.7, groups pooled), and both methods detected significant differences between genders. In addition, FIRST segmentations were consistent with manual segmentations (in a subset of images; N = 20) in the left caudate and bilateral putamen. This retrospective analysis assesses realistic performance of the algorithm in conditions like those found in multisite trials or meta-analyses. In addition, the inclusion of psychiatric patients establishes reliability in subjects exhibiting volumetric abnormalities, validating patient studies. PMID:22815187

Nugent, Allison C; Luckenbaugh, David A; Wood, Suzanne E; Bogers, Wendy; Zarate, Carlos A; Drevets, Wayne C

2013-09-01

281

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

282

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

283

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

284

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

285

Analysis of indole-3-butyric acid-induced adventitious root formation on Arabidopsis stem segments  

Microsoft Academic Search

Root induction by auxins is still not well understood at the molecular level. In this study a system has been devised which distinguishes between the two active auxins indole-3-butyric acid (IBA) and indole-3- acetic acid (IAA). IBA, but not IAA, efficiently induced adventitious rooting in Arabidopsis stem segments at a concentration of 10 lM. In wild-type plants, roots formed exclusively

Jutta Ludwig-Muller; Amy Vertocnik; Christopher D. Town

2005-01-01

286

Full-Range Analysis of Multi-Span Prestressed Concrete Segmental Bridges  

Microsoft Academic Search

The in-situ concrete stitches of prestressed concrete segmental bridge are locations of potential weakness for the entire bridge deck but relatively little work has been carried out in this area. The effects of the performance of in-situ stitches on the global behaviour of bridge deck are not well understood. As most existing techniques cannot cope with such full-range analyses, a

Francis T. K. Au; Cliff C. Y. Leung

2011-01-01

287

Abyssal Hill Segmentation: Quantitative analysis of the East Pacific Rise flanks 7°S-9°S  

NASA Astrophysics Data System (ADS)

The recent R/V Maurice Ewing EW9105 Hydrosweep survey of the East Pacific Rise (EPR) and adjacent flanks between 7°S and 9°S provides an excellent opportunity to explore the causal relationship between the ridge and the abyssal hills which form on its flanks. These data cover 100% of the flanking abyssal hills to 115 km on either side of the axis. We apply the methodology of Goff and Jordan (1988) for estimating statistical characteristics of abyssal hill morphology (rms height, characteristic lengths and widths, plan view aspect ratio, azimuthal orientation, and fractal dimension). Principal observations include the following: (1) the rms height of abyssal hill morphology is negatively correlated with the width of the 5- to 20-km-wide crestal high, consistent with the observations of Goff (1991) for northern EPR abyssal hill morphology; (2) the characteristic abyssal hill width displays no systematic variation with position relative to ridge segmentation within the EW9105 survey area, in contrast with observations of Goff (1991) for northern EPR abyssal hill morphology in which characteristic widths tend to be smallest at segment ends and largest toward the middle of segments; (3) abyssal hill rms heights and characteristic widths are very large just north of a counterclockwise rotating "nannoplate", suggesting that the overlap region is being pushed northward in response to microplate-style tectonics; and (4) within the 7°12'S-8°38'S segment, abyssal hill lineaments are generally parallel to the ridge axis, while south of this area, abyssal hill lineaments rotate with a larger "radius of curvature" than does the EPR axis approaching the EPR-Wilkes ridge-transform intersection.

Goff, John A.; Malinverno, Alberto; Fornari, Daniel J.; Cochran, James R.

1993-08-01

288

The analysis of segmental mobility with different lumbar radiographs in symptomatic patients with a spondylolisthesis  

Microsoft Academic Search

Purpose   Lumbar flexion–extension radiographs in standing position (SFE) are the most commonly used imaging method to evaluate segmental\\u000a mobility. Many surgeons use SFE to disclose abnormal vertebral motion and base their decision for surgical fusion on its results.\\u000a We tested the hypothesis that imaging in standing and recumbent position (SRP) reveals a higher sagittal translation (ST)\\u000a and sagittal rotation (SR)

Mario Cabraja; Ellafi Mohamed; Daniel Koeppen; Stefan Kroppenstedt

289

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

290

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

291

Three-dimensional volume analysis of vasculature in engineered tissues  

NASA Astrophysics Data System (ADS)

Three-dimensional textural and volumetric image analysis holds great potential in understanding the image data produced by multi-photon microscopy. In this paper, an algorithm that quantitatively analyzes the texture and the morphology of vasculature in engineered tissues is proposed. The investigated 3D artificial tissues consist of Human Umbilical Vein Endothelial Cells (HUVEC) embedded in collagen exposed to two regimes of ultrasound standing wave fields under different pressure conditions. Textural features were evaluated using the normalized Gray-Scale Cooccurrence Matrix (GLCM) combined with Gray-Level Run Length Matrix (GLRLM) analysis. To minimize error resulting from any possible volume rotation and to provide a comprehensive textural analysis, an averaged version of nine GLCM and GLRLM orientations is used. To evaluate volumetric features, an automatic threshold using the gray level mean value is utilized. Results show that our analysis is able to differentiate among the exposed samples, due to morphological changes induced by the standing wave fields. Furthermore, we demonstrate that providing more textural parameters than what is currently being reported in the literature, enhances the quantitative understanding of the heterogeneity of artificial tissues.

YousefHussien, Mohammed; Garvin, Kelley; Dalecki, Diane; Saber, Eli; Helguera, María.

2013-01-01

292

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

293

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

294

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

295

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

296

Blood volume analysis by radioisotopic dilution techniques: state of the art.  

PubMed

In the last years, there has been a growing recognition of the importance of blood volume abnormalities in the pathophysiology of several conditions and, consequently, a growing interest of accurate and rapid volume status assessment. Accordingly, there has been a surge of interest in blood volume analysis by radioisotopic dilution technique. However, there are still some controversies about this technique, such as the use of the f-cell ratio, the errors associated with the method and the reference values. This review aims to revise and discuss the theoretical and methodological aspects of this technique and also to discuss their controversies. Furthermore, it is questioned whether red cell volume or plasma volume can be accurately estimated once the other quantity has been measured or should red cell volume and plasma volume be directly measured. As a conclusion, blood volume analysis by radioisotopic dilution technique is still valid and very useful. PMID:25479437

Gómez Perales, Jesús Luis

2015-02-01

297

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

298

Texture-based segmentation and analysis of emphysema depicted on CT images  

NASA Astrophysics Data System (ADS)

In this study we present a texture-based method of emphysema segmentation depicted on CT examination consisting of two steps. Step 1, a fractal dimension based texture feature extraction is used to initially detect base regions of emphysema. A threshold is applied to the texture result image to obtain initial base regions. Step 2, the base regions are evaluated pixel-by-pixel using a method that considers the variance change incurred by adding a pixel to the base in an effort to refine the boundary of the base regions. Visual inspection revealed a reasonable segmentation of the emphysema regions. There was a strong correlation between lung function (FEV1%, FEV1/FVC, and DLCO%) and fraction of emphysema computed using the texture based method, which were -0.433, -.629, and -0.527, respectively. The texture-based method produced more homogeneous emphysematous regions compared to simple thresholding, especially for large bulla, which can appear as speckled regions in the threshold approach. In the texture-based method, single isolated pixels may be considered as emphysema only if neighboring pixels meet certain criteria, which support the idea that single isolated pixels may not be sufficient evidence that emphysema is present. One of the strength of our complex texture-based approach to emphysema segmentation is that it goes beyond existing approaches that typically extract a single or groups texture features and individually analyze the features. We focus on first identifying potential regions of emphysema and then refining the boundary of the detected regions based on texture patterns.

Tan, Jun; Zheng, Bin; Wang, Xingwei; Lederman, Dror; Pu, Jiantao; Sciurba, Frank C.; Gur, David; Leader, J. Ken

2011-03-01

299

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

300

Segmentation of acute pyelonephritis area on kidney SPECT images using binary shape analysis  

NASA Astrophysics Data System (ADS)

Acute pyelonephritis is a serious disease in children that may result in irreversible renal scarring. The ability to localize the site of urinary tract infection and the extent of acute pyelonephritis has considerable clinical importance. In this paper, we are devoted to segment the acute pyelonephritis area from kidney SPECT images. A two-step algorithm is proposed. First, the original images are translated into binary versions by automatic thresholding. Then the acute pyelonephritis areas are located by finding convex deficiencies in the obtained binary images. This work gives important diagnosis information for physicians and improves the quality of medical care for children acute pyelonephritis disease.

Wu, Chia-Hsiang; Sun, Yung-Nien; Chiu, Nan-Tsing

1999-05-01

301

Efficacy of bronchoscopic lung volume reduction: a meta-analysis  

PubMed Central

Background Over the last several years, the morbidity, mortality, and high costs associated with lung volume reduction (LVR) surgery has fuelled the development of different methods for bronchoscopic LVR (BLVR) in patients with emphysema. In this meta-analysis, we sought to study and compare the efficacy of most of these methods. Methods Eligible studies were retrieved from PubMed and Embase for the following BLVR methods: one-way valves, sealants (BioLVR), LVR coils, airway bypass stents, and bronchial thermal vapor ablation. Primary study outcomes included the mean change post-intervention in the lung function tests, the 6-minute walk distance, and the St George’s Respiratory Questionnaire. Secondary outcomes included treatment-related complications. Results Except for the airway bypass stents, all other methods of BLVR showed efficacy in primary outcomes. However, in comparison, the BioLVR method showed the most significant findings and was the least associated with major treatment-related complications. For the BioLVR method, the mean change in forced expiratory volume (in first second) was 0.18 L (95% confidence interval [CI]: 0.09 to 0.26; P<0.001); in 6-minute walk distance was 23.98 m (95% CI: 12.08 to 35.88; P<0.01); and in St George’s Respiratory Questionnaire was -8.88 points (95% CI: ?12.12 to ?5.64; P<0.001). Conclusion The preliminary findings of our meta-analysis signify the importance of most methods of BLVR. The magnitude of the effect on selected primary outcomes shows noninfe-riority, if not equivalence, when compared to what is known for surgical LVR. PMID:24868153

Iftikhar, Imran H; McGuire, Franklin R; Musani, Ali I

2014-01-01

302

Synfuel program analysis. Volume 1: Procedures-capabilities  

NASA Astrophysics Data System (ADS)

The analytic procedures and capabilities developed by Resource Applications (RA) for examining the economic viability, public costs, and national benefits of alternative are described. This volume is intended for Department of Energy (DOE) and Synthetic Fuel Corporation (SFC) program management personnel and includes a general description of the costing, venture, and portfolio models with enough detail for the reader to be able to specify cases and interpret outputs. It contains an explicit description (with examples) of the types of results which can be obtained when applied for the analysis of individual projects; the analysis of input uncertainty, i.e., risk; and the analysis of portfolios of such projects, including varying technology mixes and buildup schedules. The objective is to obtain, on the one hand, comparative measures of private investment requirements and expected returns (under differing public policies) as they affect the private decision to proceed, and, on the other, public costs and national benefits as they affect public decisions to participate (in what form, in what areas, and to what extent).

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

1980-07-01

303

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

304

Techniques in helical scanning, dynamic imaging and image segmentation for improved quantitative analysis with X-ray micro-CT  

NASA Astrophysics Data System (ADS)

This paper reports on recent advances at the micro-computed tomography facility at the Australian National University. Since 2000 this facility has been a significant centre for developments in imaging hardware and associated software for image reconstruction, image analysis and image-based modelling. In 2010 a new instrument was constructed that utilises theoretically-exact image reconstruction based on helical scanning trajectories, allowing higher cone angles and thus better utilisation of the available X-ray flux. We discuss the technical hurdles that needed to be overcome to allow imaging with cone angles in excess of 60°. We also present dynamic tomography algorithms that enable the changes between one moment and the next to be reconstructed from a sparse set of projections, allowing higher speed imaging of time-varying samples. Researchers at the facility have also created a sizeable distributed-memory image analysis toolkit with capabilities ranging from tomographic image reconstruction to 3D shape characterisation. We show results from image registration and present some of the new imaging and experimental techniques that it enables. Finally, we discuss the crucial question of image segmentation and evaluate some recently proposed techniques for automated segmentation.

Sheppard, Adrian; Latham, Shane; Middleton, Jill; Kingston, Andrew; Myers, Glenn; Varslot, Trond; Fogden, Andrew; Sawkins, Tim; Cruikshank, Ron; Saadatfar, Mohammad; Francois, Nicolas; Arns, Christoph; Senden, Tim

2014-04-01

305

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

306

Full automation of morphological segmentation of retinal images: a comparison with human-based analysis  

NASA Astrophysics Data System (ADS)

Age-Related Macular Degeneration (ARMD) is the leading cause of irreversible visual loss among the elderly in the US and Europe. A computer-based system has been developed to provide the ability to track the position and margin of the ARMD associated lesion; drusen. Variations in the subject's retinal pigmentation, size and profusion of the lesions, and differences in image illumination and quality present significant challenges to most segmentation algorithms. An algorithm is presented that first classifies the image to optimize the variables of a mathematical morphology algorithm. A binary image is found by applying Otsu's method to the reconstructed image. Lesion size and area distribution statistics are then calculated. For training and validation, the University of Wisconsin provided longitudinal images of 22 subjects from their 10 year Beaver Dam Study. Using the Wisconsin Age-Related Maculopathy Grading System, three graders classified the retinal images according to drusen size and area of involvement. The percentages within the acceptable error between the three graders and the computer are as follows: Grader-A: Area: 84% Size: 81%; Grader-B: Area: 63% Size: 76%; Grader-C: Area: 81% Size: 88%. To validate the segmented position and boundary one grader was asked to digitally outline the drusen boundary. The average accuracy based on sensitivity and specificity was 0.87 for thirty four marked regions.

Wilson, Mark P.; Yang, Shuyu; Mitra, Sunanda; Raman, Balaji; Nemeth, Sheila C.; Soliz, Peter

2003-05-01

307

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

308

Support trusses for large precision segmented reflectors: Preliminary design and analysis  

NASA Technical Reports Server (NTRS)

Precision Segmented Reflector (PSR) technology is currently being developed for a range of future applications such as the Large Deployable Reflector. The structures activities at NASA-Langley are outlined in support of the PSR program. Design concepts are explored for erectable and deployable support structures which are envisioned to be the backbone of these precision reflectors. Important functional requirements for the support trusses related to stiffness, mass, and surface accuracy are reviewed. Proposed geometries for these structures and factors motivating the erectable and deployable designs are discussed. Analytical results related to stiffness, dynamic behavior, and surface accuracy are presented and considered in light of the functional requirements. Results are included for both a 4-meter-diameter prototype support truss which is currently being designed as the Test Bed for the PSR technology development program, and for two 20-meter support structures.

Collins, Timothy J.; Fichter, W. B.

1989-01-01

309

Analysis of different material theories used in a FE model of a lumbar segment motion.  

PubMed

In this study, a nonlinear poroelastic model of intervertebral disc as an infrastructure was developed. Moreover, a new element was defined consisting a disc (Viscoelastic Euler Beam Element) and a vertebra (Rigid Link) as a unit element. Using the new element, three different viscoelastic finite element models were prepared for lumbar motion segment (L4/L5). Prolonged loading (short-term and longterm creep) and cyclic loading were applied to the models and the results were compared with results of in vivo tests. Simplification of the models by using the new element leads to reduction of the runtime of the models in dynamic analyses to few minutes without losing the accuracy in the results. PMID:23952458

Gohari, Ehsan; Nikkhoo, Mohammad; Haghpanahi, Mohammad; Parnianpour, Mohammad

2013-01-01

310

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

311

The Integraton of Graph-Based Knowledge Discovery with Image Segmentation Hierarchies for Data Analysis, Data Mining and Knowledge Discovery  

Microsoft Academic Search

We will present a progress report on a project that seeks to integrate a graph based knowledge discovery system called Subdue with image segmentation hierarchies produced by a hierarchical image segmentation approach called RHSEG. It is expected that RHSEG segmentations will abstract the image pixel data into region objects from which Subdue will be able to discover or identify meaningful

James C. Tilton; Diane J. Cook; Nikhil S. Ketkar

2008-01-01

312

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<0.001). Compared with DEXA, sBIA significantly overestimated whole-body LM and BMC (1,126 g and 382 g, respectively, p<0.01). The Bland-Altman 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<0.001). However, sBIA significantly overestimated LM of the trunk and legs and underestimated the appendicular FM percentage. Verified by DEXA, sBIA provides reliable measures of whole-body LM, FM, and trunk FM in heavy smokers. A lesser degree of agreement was found for BMC, appendicular LM, and FM. PMID:25315614

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

2015-01-01

313

Yucca Mountain transportation routes: Preliminary characterization and risk analysis; Volume 2, Figures [and] Volume 3, Technical Appendices  

SciTech Connect

This report presents appendices related to the preliminary assessment and risk analysis for high-level radioactive waste transportation routes to the proposed Yucca Mountain Project repository. Information includes data on population density, traffic volume, ecologically sensitive areas, and accident history.

Souleyrette, R.R. II; Sathisan, S.K.; di Bartolo, R. [Nevada Univ., Las Vegas, NV (United States). Transportation Research Center

1991-05-31

314

Incorporation of learned shape priors into a graph-theoretic approach with application to the 3D segmentation of intraretinal surfaces in SD-OCT volumes of mice  

NASA Astrophysics Data System (ADS)

Spectral-domain optical coherence tomography (SD-OCT) finds widespread use clinically for the detection and management of ocular diseases. This non-invasive imaging modality has also begun to find frequent use in research studies involving animals such as mice. Numerous approaches have been proposed for the segmentation of retinal surfaces in SD-OCT images obtained from human subjects; however, the segmentation of retinal surfaces in mice scans is not as well-studied. In this work, we describe a graph-theoretic segmentation approach for the simultaneous segmentation of 10 retinal surfaces in SD-OCT scans of mice that incorporates learned shape priors. We compared the method to a baseline approach that did not incorporate learned shape priors and observed that the overall unsigned border position errors reduced from 3.58 +/- 1.33 ?m to 3.20 +/- 0.56 ?m.

Antony, Bhavna J.; Song, Qi; Abràmoff, Michael D.; Sohn, Eliott; Wu, Xiaodong; Garvin, Mona K.

2014-03-01

315

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

316

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

317

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

318

Segmentation and Tracking of Adherens Junctions in 3D for the Analysis of Epithelial Tissue Morphogenesis  

PubMed Central

Epithelial morphogenesis generates the shape of tissues, organs and embryos and is fundamental for their proper function. It is a dynamic process that occurs at multiple spatial scales from macromolecular dynamics, to cell deformations, mitosis and apoptosis, to coordinated cell rearrangements that lead to global changes of tissue shape. Using time lapse imaging, it is possible to observe these events at a system level. However, to investigate morphogenetic events it is necessary to develop computational tools to extract quantitative information from the time lapse data. Toward this goal, we developed an image-based computational pipeline to preprocess, segment and track epithelial cells in 4D confocal microscopy data. The computational pipeline we developed, for the first time, detects the adherens junctions of epithelial cells in 3D, without the need to first detect cell nuclei. We accentuate and detect cell outlines in a series of steps, symbolically describe the cells and their connectivity, and employ this information to track the cells. We validated the performance of the pipeline for its ability to detect vertices and cell-cell contacts, track cells, and identify mitosis and apoptosis in surface epithelia of Drosophila imaginal discs. We demonstrate the utility of the pipeline to extract key quantitative features of cell behavior with which to elucidate the dynamics and biomechanical control of epithelial tissue morphogenesis. We have made our methods and data available as an open-source multiplatform software tool called TTT (http://github.com/morganrcu/TTT) PMID:25884654

Cilla, Rodrigo; Mechery, Vinodh; Hernandez de Madrid, Beatriz; Del Signore, Steven; Dotu, Ivan; Hatini, Victor

2015-01-01

319

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

PubMed

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

2013-03-01

320

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

321

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

322

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

323

Linkage disequilibrium analysis by searching for shared segments: Mapping a locus for benign recurrent intrahepatic cholestasis (BRIC)  

SciTech Connect

The lod score method of linkage analysis has two important drawbacks: parameters must be specified for the transmission of the disease (e.g. penetrance), and large numbers of genetically informative individuals must be studied. Although several robust non-parametric methods are available, these also require large sample sizes. The availability of dense genetic maps permits genome screening to be conducted by linkage disequilibrium (LD) mapping methods, which are statistically powerful and non-parametric. Lander & Botstein proposed that LD mapping could be employed to screen the human genome for disease loci; we have now applied this strategy to map a gene for an autosomal recessive disorder, benign recurrent intrahepatic cholestatis (BRIC). Our approach to LD mapping was based on identifying chromosome segments shared between distantly related patients; we used 256 microsatellite markers to genotype three affected individuals, and their parents, from an isolated town in The Netherlands. Because endogamy occurred in this population for several generations, all of the BRIC patients are known to be distantly related to each other, but the pedigree structure and connections could not be certainly established more than three generations before the present, so lod score analysis was impossible. A 20 cM region on chromosome 18 is shared by 5/6 patient chromosomes; subsequently, we noted that 6/6 chromosomes shared an interval of about 3 cM in this region. Calculations indicate that it is extremely unlikely that such a region could be inherited by chance rather than by descent from a common ancestor. Thus, LD mapping by searching for shared chromosomal segments is an extremely powerful approach for genome screening to identify disease loci.

Freimer, N.; Baharloo, S.; Blankenship, K. [Univ. of California, San Francisco, CA (United States)] [and others

1994-09-01

324

A Genetic Analysis of Brain Volumes and IQ in Children  

ERIC Educational Resources Information Center

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…

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

2009-01-01

325

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...

326

Conjoint Analysis of Study Abroad Preferences: Key Attributes, Segments and Implications for Increasing Student Participation  

ERIC Educational Resources Information Center

An adaptive conjoint analysis was performed on the study abroad preferences of a sample of undergraduate college students. The results indicate that trip location, cost, and time spent abroad are the three most important determinants of student preference for different study abroad trip scenarios. The analysis also uncovered four different study…

Garver, Michael S.; Divine, Richard L.

2008-01-01

327

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

328

Local analysis of human cortex in MRI brain volume.  

PubMed

This paper describes a method for subcortical identification and labeling of 3D medical MRI images. Indeed, the ability to identify similarities between the most characteristic subcortical structures such as sulci and gyri is helpful for human brain mapping studies in general and medical diagnosis in particular. However, these structures vary greatly from one individual to another because they have different geometric properties. For this purpose, we have developed an efficient tool that allows a user to start with brain imaging, to segment the border gray/white matter, to simplify the obtained cortex surface, and to describe this shape locally in order to identify homogeneous features. In this paper, a segmentation procedure using geometric curvature properties that provide an efficient discrimination for local shape is implemented on the brain cortical surface. Experimental results demonstrate the effectiveness and the validity of our approach. PMID:24688452

Bourouis, Sami

2014-01-01

329

Risk factors for neovascular glaucoma after carbon ion radiotherapy of choroidal melanoma using dose-volume histogram analysis  

SciTech Connect

Purpose: To determine the risk factors for neovascular glaucoma (NVG) after carbon ion radiotherapy (C-ion RT) of choroidal melanoma. Methods and Materials: A total of 55 patients with choroidal melanoma were treated between 2001 and 2005 with C-ion RT based on computed tomography treatment planning. All patients had a tumor of large size or one located close to the optic disk. Univariate and multivariate analyses were performed to identify the risk factors of NVG for the following parameters; gender, age, dose-volumes of the iris-ciliary body and the wall of eyeball, and irradiation of the optic disk (ODI). Results: Neovascular glaucoma occurred in 23 patients and the 3-year cumulative NVG rate was 42.6 {+-} 6.8% (standard error), but enucleation from NVG was performed in only three eyes. Multivariate analysis revealed that the significant risk factors for NVG were V50{sub IC} (volume irradiated {>=}50 GyE to iris-ciliary body) (p = 0.002) and ODI (p = 0.036). The 3-year NVG rate for patients with V50{sub IC} {>=}0.127 mL and those with V50{sub IC} <0.127 mL were 71.4 {+-} 8.5% and 11.5 {+-} 6.3%, respectively. The corresponding rate for the patients with and without ODI were 62.9 {+-} 10.4% and 28.4 {+-} 8.0%, respectively. Conclusion: Dose-volume histogram analysis with computed tomography indicated that V50{sub IC} and ODI were independent risk factors for NVG. An irradiation system that can reduce the dose to both the anterior segment and the optic disk might be worth adopting to investigate whether or not incidence of NVG can be decreased with it.

Hirasawa, Naoki [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba (Japan) and Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya (Japan)]. E-mail: naoki_h@nirs.go.jp; Tsuji, Hiroshi [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba (Japan); Ishikawa, Hitoshi [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba (Japan); Koyama-Ito, Hiroko [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba (Japan); Kamada, Tadashi [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba (Japan); Mizoe, Jun-Etsu [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba (Japan); Ito, Yoshiyuki [Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Naganawa, Shinji [Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Ohnishi, Yoshitaka [Departments of Ophthalmology, Wakayama Medical University, Wakayama (Japan); Tsujii, Hirohiko [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba (Japan)

2007-02-01

330

Improving image segmentation performance and quantitative analysis via a computer-aided grading methodology for optical coherence tomography retinal image analysis  

NASA Astrophysics Data System (ADS)

We demonstrate quantitative analysis and error correction of optical coherence tomography (OCT) retinal images by using a custom-built, computer-aided grading methodology. A total of 60 Stratus OCT (Carl Zeiss Meditec, Dublin, California) B-scans collected from ten normal healthy eyes are analyzed by two independent graders. The average retinal thickness per macular region is compared with the automated Stratus OCT results. Intergrader and intragrader reproducibility is calculated by Bland-Altman plots of the mean difference between both gradings and by Pearson correlation coefficients. In addition, the correlation between Stratus OCT and our methodology-derived thickness is also presented. The mean thickness difference between Stratus OCT and our methodology is 6.53 ?m and 26.71 ?m when using the inner segment/outer segment (IS/OS) junction and outer segment/retinal pigment epithelium (OS/RPE) junction as the outer retinal border, respectively. Overall, the median of the thickness differences as a percentage of the mean thickness is less than 1% and 2% for the intragrader and intergrader reproducibility test, respectively. The measurement accuracy range of the OCT retinal image analysis (OCTRIMA) algorithm is between 0.27 and 1.47 ?m and 0.6 and 1.76 ?m for the intragrader and intergrader reproducibility tests, respectively. Pearson correlation coefficients demonstrate R2>0.98 for all Early Treatment Diabetic Retinopathy Study (ETDRS) regions. Our methodology facilitates a more robust and localized quantification of the retinal structure in normal healthy controls and patients with clinically significant intraretinal features.

Cabrera Debuc, Delia; Salinas, Harry M.; Ranganathan, Sudarshan; Tátrai, Erika; Gao, Wei; Shen, Meixiao; Wang, Jianhua; Somfai, Gábor M.; Puliafito, Carmen A.

2010-07-01

331

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

332

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. PMID:24935086

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

2015-02-01

333

Genetic characterization of Indian peste des petits ruminants virus (PPRV) by sequencing and phylogenetic analysis of fusion protein and nucleoprotein gene segments  

Microsoft Academic Search

Peste des petits ruminants (PPR) is an important viral disease of sheep and goats, endemic in India. The study was undertaken to characterize the local PPRV by sequencing fusion (F) protein and nucleoprotein (N) gene segments and phylogenetic analysis, so as to focus on genetic variation in the field viruses. Selected regions of PPRV genome were amplified from clinical samples

N. Kerur; M. K. Jhala; C. G. Joshi

2008-01-01

334

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...

335

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

336

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

337

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...

338

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...

339

Segmentations of MRI Images of the Female Pelvic Floor: A Study of Inter- and Intra-reader Reliability  

PubMed Central

Purpose To describe the inter- and intra-operator reliability of segmentations of female pelvic floor structures. Materials and Methods Three segmentation specialists were asked to segment out the female pelvic structures in 20 MR datasets on three separate occasions. The STAPLE algorithm was used to compute inter- and intra-segmenter agreement of each organ in each dataset. STAPLE computed the sensitivity, specificity, and positive predictive values (PPV) for inter- and intra-segmenter repeatability. These parameters were analyzed using intra-class correlation analysis. Correlation of organ volume to PPV and sensitivity was also computed. Results Mean PPV of the segmented organs ranged from 0.82 to 0.99, and sensitivity ranged from 33 to 96%. Intra-class correlation ranged from 0.07 to 0.98 across segmenters. Pearson correlation of volume to sensitivity were significant across organs, ranging from 0.54 to 0.91. Organs with significant correlation of PPV to volume were bladder (?0.69), levator ani (?0.68), and coccyx (?0.63). Conclusion Undirected manual segmentation of the pelvic floor organs are adequate for locating the organs, but poor at defining structural boundaries. PMID:21563253

Hoyte, Lennox; Ye, Wen; Brubaker, Linda; Fielding, Julia R.; Lockhart, Mark E.; Heilbrun, Marta E.; Brown, Morton B.; Warfield, Simon K.

2015-01-01

340

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

341

Automated segmentation of the lamina cribrosa using Frangi's filter: a novel approach for rapid identification of tissue volume fraction and beam orientation in a trabeculated structure in the eye.  

PubMed

The lamina cribrosa (LC) is a tissue in the posterior eye with a complex trabecular microstructure. This tissue is of great research interest, as it is likely the initial site of retinal ganglion cell axonal damage in glaucoma. Unfortunately, the LC is difficult to access experimentally, and thus imaging techniques in tandem with image processing have emerged as powerful tools to study the microstructure and biomechanics of this tissue. Here, we present a staining approach to enhance the contrast of the microstructure in micro-computed tomography (micro-CT) imaging as well as a comparison between tissues imaged with micro-CT and second harmonic generation (SHG) microscopy. We then apply a modified version of Frangi's vesselness filter to automatically segment the connective tissue beams of the LC and determine the orientation of each beam. This approach successfully segmented the beams of a porcine optic nerve head from micro-CT in three dimensions and SHG microscopy in two dimensions. As an application of this filter, we present finite-element modelling of the posterior eye that suggests that connective tissue volume fraction is the major driving factor of LC biomechanics. We conclude that segmentation with Frangi's filter is a powerful tool for future image-driven studies of LC biomechanics. PMID:25589572

Campbell, Ian C; Coudrillier, Baptiste; Mensah, Johanne; Abel, Richard L; Ethier, C Ross

2015-03-01

342

A Framework for Audio Analysis based on Classification and Temporal Segmentation  

Microsoft Academic Search

Abstract Existing audio tools handle the increasing amount of computer audio data inadequately. The typical tape-recorder paradigm for audio interfaces is inflexible and time consuming, especially for large data sets. On the other hand, completely automatic audio analysis and annotation is impossible using current techniques. Alternative solutions are semi-automatic user interfaces that let users interact with sound in flexible ways

George Tzanetakis; Perry R. Cook

1999-01-01

343

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

344

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

345

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

E-print Network

for mobile gait analysis. The first is a basic, model-based algorithm which operates directly on the joint angles computed by the Orient sensor devices. The second is a model-free, Latent Space algo- rithm, which in a hospital-based clinical study for analysing the motion of elderly patients recovering from a fall. Keywords

346

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

347

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

348

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

349

Quantitative analysis using the star volume method applied to skeleton patterns extracted with a morphological filter  

Microsoft Academic Search

In this study, a morphological filter was combined with star volume analysis and applied to digital images to determine\\u000a its potential usefulness in assessing trabecular structure. Three digital \\

Akitoshi Ikuta; Satsuki Kumasaka; Isamu Kashima

2000-01-01

350

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

351

Intelligent marketing strategies for the Hard Rock Hotel and Casino, Las Vegas; market segmentation and customer analysis  

Microsoft Academic Search

The Hard Rock Hotel & Casino (HRHC) in Las Vegas, NV hopes to implement customer relationship management (CRM) strategies to increase overall customer value. This paper discusses our process of analyzing historical customer data and creating incentives tests in order to create accurate and useful customer segments. These customer segments can be used to target customers based on their interests,

Leah M. Churinske; Taylor Lee; Nivaan Linhares; Selenge Turbat; Francesca Wolf; W. T. Scherer

2010-01-01

352

Automatic MRI 2D brain segmentation using graph searching technique.  

PubMed

Accurate and efficient segmentation of the whole brain in magnetic resonance (MR) images is a key task in many neuroscience and medical studies either because the whole brain is the final anatomical structure of interest or because the automatic extraction facilitates further analysis. The problem of segmenting brain MRI images has been extensively addressed by many researchers. Despite the relevant achievements obtained, automated segmentation of brain MRI imagery is still a challenging problem whose solution has to cope with critical aspects such as anatomical variability and pathological deformation. In the present paper, we describe and experimentally evaluate a method for segmenting brain from MRI images basing on two-dimensional graph searching principles for border detection. The segmentation of the whole brain over the entire volume is accomplished slice by slice, automatically detecting frames including eyes. The method is fully automatic and easily reproducible by computing the internal main parameters directly from the image data. The segmentation procedure is conceived as a tool of general applicability, although design requirements are especially commensurate with the accuracy required in clinical tasks such as surgical planning and post-surgical assessment. Several experiments were performed to assess the performance of the algorithm on a varied set of MRI images obtaining good results in terms of accuracy and stability. PMID:23757180

Pedoia, Valentina; Binaghi, Elisabetta

2013-09-01

353

Fast prostate segmentation for brachytherapy based on joint fusion of images and labels  

NASA Astrophysics Data System (ADS)

Brachytherapy as one of the treatment methods for prostate cancer takes place by implantation of radioactive seeds inside the gland. The standard of care for this treatment procedure is to acquire transrectal ultrasound images of the prostate which are segmented in order to plan the appropriate seed placement. The segmentation process is usually performed either manually or semi-automatically and is associated with subjective errors because the prostate visibility is limited in ultrasound images. The current segmentation process also limits the possibility of intra-operative delineation of the prostate to perform real-time dosimetry. In this paper, we propose a computationally inexpensive and fully automatic segmentation approach that takes advantage of previously segmented images to form a joint space of images and their segmentations. We utilize joint Independent Component Analysis method to generate a model which is further employed to produce a probability map of the target segmentation. We evaluate this approach on the transrectal ultrasound volume images of 60 patients using a leave-one-out cross-validation approach. The results are compared with the manually segmented prostate contours that were used by clinicians to plan brachytherapy procedures. We show that the proposed approach is fast with comparable accuracy and precision to those found in previous studies on TRUS segmentation.

Nouranian, Saman; Ramezani, Mahdi; Mahdavi, S. Sara; Spadinger, Ingrid; Morris, William J.; Salcudean, Septimiu E.; Abolmaesumi, Purang

2014-03-01

354

The power-proportion method for intracranial volume correction in volumetric imaging analysis  

PubMed Central

In volumetric brain imaging analysis, volumes of brain structures are typically assumed to be proportional or linearly related to intracranial volume (ICV). However, evidence abounds that many brain structures have power law relationships with ICV. To take this relationship into account in volumetric imaging analysis, we propose a power law based method—the power-proportion method—for ICV correction. The performance of the new method is demonstrated using data from the PREDICT-HD study. PMID:25414635

Liu, Dawei; Johnson, Hans J.; Long, Jeffrey D.; Magnotta, Vincent A.; Paulsen, Jane S.

2014-01-01

355

Design and experimental gait analysis of a multi-segment in-pipe robot inspired by earthworm's peristaltic locomotion  

NASA Astrophysics Data System (ADS)

This paper reports the experimental progress towards developing a multi-segment in-pipe robot inspired by earthworm's body structure and locomotion mechanism. To mimic the alternating contraction and elongation of a single earthworm's segment, a robust, servomotor based actuation mechanism is developed. In each robot segment, servomotor-driven cords and spring steel belts are utilized to imitate the earthworm's longitudinal and circular muscles, respectively. It is shown that the designed segment can contract and relax just like an earthworm's body segment. The axial and radial deformation of a single segment is measured experimentally, which agrees with the theoretical predictions. Then a multisegment earthworm-like robot is fabricated by assembling eight identical segments in series. The locomotion performance of this robot prototype is then extensively tested in order to investigate the correlation between gait design and dynamic locomotion characteristics. Based on the principle of retrograde peristalsis wave, a gait generator is developed for the multi-segment earthworm-like robot, following which gaits of the robot can be constructed. Employing the generated gaits, the 8-segment earthworm-like robot can successfully perform both horizontal locomotion and vertical climb in pipes. By changing gait parameters, i.e., with different gaits, locomotion characteristics including average speed and anchor slippage can be significantly tailored. The proposed actuation method and prototype of the multi-segment in-pipe robot as well as the gait generator provide a bionic realization of earthworm's locomotion with promising potentials in various applications such as pipeline inspection and cleaning.

Fang, Hongbin; Wang, Chenghao; Li, Suyi; Xu, Jian; Wang, K. W.

2014-03-01

356

Vibration damping for the Segmented Mirror Telescope  

NASA Astrophysics Data System (ADS)

The Segmented Mirror Telescope (SMT) at the Naval Postgraduate School (NPS) in Monterey is a next-generation deployable telescope, featuring a 3-meter 6-segment primary mirror and advanced wavefront sensing and correction capabilities. In its stowed configuration, the SMT primary mirror segments collapse into a small volume; once on location, these segments open to the full 3-meter diameter. The segments must be very accurately aligned after deployment and the segment surfaces are actively controlled using numerous small, embedded actuators. The SMT employs a passive damping system to complement the actuators and mitigate the effects of low-frequency (<40 Hz) vibration modes of the primary mirror segments. Each of the six segments has three or more modes in this bandwidth, and resonant vibration excited by acoustics or small disturbances on the structure can result in phase mismatches between adjacent segments thereby degrading image quality. The damping system consists of two tuned mass dampers (TMDs) for each of the mirror segments. An adjustable TMD with passive magnetic damping was selected to minimize sensitivity to changes in temperature; both frequency and damping characteristics can be tuned for optimal vibration mitigation. Modal testing was performed with a laser vibrometry system to characterize the SMT segments with and without the TMDs. Objectives of this test were to determine operating deflection shapes of the mirror and to quantify segment edge displacements; relative alignment of ?/4 or better was desired. The TMDs attenuated the vibration amplitudes by 80% and reduced adjacent segment phase mismatches to acceptable levels.

Maly, Joseph R.; Yingling, Adam J.; Griffin, Steven F.; Agrawal, Brij N.; Cobb, Richard G.; Chambers, Trevor S.

2012-09-01

357

A new method of cardiographic image segmentation based on grammar  

NASA Astrophysics Data System (ADS)

The measurement of the most common ultrasound parameters, such as aortic area, mitral area and left ventricle (LV) volume, requires the delineation of the organ in order to estimate the area. In terms of medical image processing this translates into the need to segment the image and define the contours as accurately as possible. The aim of this work is to segment an image and make an automated area estimation based on grammar. The entity "language" will be projected to the entity "image" to perform structural analysis and parsing of the image. We will show how the idea of segmentation and grammar-based area estimation is applied to real problems of cardio-graphic image processing.

Hamdi, Salah; Ben Abdallah, Asma; Bedoui, Mohamed H.; Alimi, Adel M.

2011-10-01

358

Estimation of the Click Volume by Large Scale Regression Analysis  

E-print Network

advertisement can potentially receive in the current market? We call this the click volume estimation problem. In the latter case an AE can skip some ad request even if advertisers mark it as belonging to their target group advertisers to understand whether their target description is good enough. ­ Assuming we have a purchase

Lifshits, Yury

359

Learning static object segmentation from motion segmentation  

E-print Network

This thesis describes the SANE (Segmentation According to Natural Examples) algorithm for learning to segment objects in static images from video data. SANE uses background subtraction to find the segmentation of moving ...

Ross, Michael G. (Michael Gregory), 1975-

2005-01-01

360

An approach to dissecting the congenitally malformed heart in the forensic autopsy: the value of sequential segmental analysis.  

PubMed

The demonstration of congenital heart disease at autopsy necessitates the careful preservation and examination of the heart, the vessels, and their connections. Techniques preserving these connections and using a reproducible and systematic approach are preferred. The Rokitansky method of organ block dissection, in combination with a system of heart examination termed sequential segmental analysis, provides such an approach. This study is based on the examination of heart specimens accessioned into the Frank E. Sherman, M.D., and Cora C. Lenox, M.D., Heart Museum (containing approximately 2400 specimens) of the Pathology Department, Children's Hospital of Pittsburgh. Specimens received in consultation during a 25-year period from hospitals and coroners'/medical examiners' offices were examined, and the corresponding reports were reviewed. Of 46 total heart specimens examined (1975-1999), 29 (63%) were dissected properly or left intact for dissection at Children's Hospital of Pittsburgh, and 17 (37%) were incorrectly dissected for the demonstration of congenital heart disease. Of these 17 cases, 11 (24%) displayed dissection errors, which did not hinder a complete diagnosis, 3 cases (6.5%) had errors that enabled only an incomplete diagnosis, and in 3 cases (6.5%), no diagnosis of congenital heart disease could be made. Dissection mistakes and means of avoiding them are discussed. Review of medical and family history, external and internal examination, and a reproducible and sequential method of examining the heart and its connections enables documentation of even the most complex cardiovascular anomalies. PMID:11764911

Horn, K D; Devine, W A

2001-12-01

361

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

362

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

363

Micro-computed tomography-based highly automated 3D segmentation of the rat spine for quantitative analysis of metastatic disease.  

PubMed

Noninvasive evaluation of metastatic disease in the spine has generally been limited to 2D qualitative or semiquantitative analysis techniques. This study aims to develop and evaluate a highly automated micro-CT-based quantitative analysis tool that can measure the architectural impact of metastatic involvement in whole vertebrae. Micro-CT analysis of rat whole vertebrae was conducted using a combination of demons deformable registration, level set curvature evolution, and intensity based thresholding techniques along with upsampling and edge enhancement techniques. The algorithm was applied to 6 lumbar vertebrae (L1-3) from 6 rnu/rnu rats (3 healthy rats and 3 with metastatic involvement). Osteolytic metastatic involvement was modeled via MT1 human breast cancer cells. Excellent volumetric concurrency was achieved in comparing the automated micro-CT-based segmentations of the whole vertebrae, trabecular centrums, and individual trabecular networks to manual segmentations (98.9%, 96.1%, and 98.3%, respectively; 6 specimens), and the automated segmentations were achieved in a fraction of the time. The algorithm successfully accounted for discontinuities in the cortical shell caused by vasculature and osteolytic destruction. As such, this work demonstrates the potential of this highly automated segmentation tool to permit rapid precise quantitative structural analysis of the spine with minimum user interaction in the analysis of both healthy and pathological (metastatically involved) vertebrae. Future optimization and the incorporation of lower-resolution imaging parameters may allow automated analysis of clinical CT-based measures in addition to preclinical micro-CT-based analyses of the structural impact and progression of pathological processes in the spine. PMID:20809732

Hojjat, Seyed-Parsa; Hardisty, Michael R; Whyne, Cari M

2010-09-01

364

Price-volume multifractal analysis and its application in Chinese stock markets  

NASA Astrophysics Data System (ADS)

An empirical research on Chinese stock markets is conducted using statistical tools. First, the multifractality of stock price return series, ri(ri=ln(Pt+1)-ln(Pt)) and trading volume variation series, vi(vi=ln(Vt+1)-ln(Vt)) is confirmed using multifractal detrended fluctuation analysis. Furthermore, a multifractal detrended cross-correlation analysis between stock price return and trading volume variation in Chinese stock markets is also conducted. It is shown that the cross relationship between them is also found to be multifractal. Second, the cross-correlation between stock price Pi and trading volume Vi is empirically studied using cross-correlation function and detrended cross-correlation analysis. It is found that both Shanghai stock market and Shenzhen stock market show pronounced long-range cross-correlations between stock price and trading volume. Third, a composite index R based on price and trading volume is introduced. Compared with stock price return series ri and trading volume variation series vi, R variation series not only remain the characteristics of original series but also demonstrate the relative correlation between stock price and trading volume. Finally, we analyze the multifractal characteristics of R variation series before and after three financial events in China (namely, Price Limits, Reform of Non-tradable Shares and financial crisis in 2008) in the whole period of sample to study the changes of stock market fluctuation and financial risk. It is found that the empirical results verified the validity of R.

Yuan, Ying; Zhuang, Xin-tian; Liu, Zhi-ying

2012-06-01

365

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

366

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

367

Electric-generation expansion-analysis system. Volume 3. Computer program user's manual. Final report  

SciTech Connect

EGEAS is a modular state-of-the-art capacity expansion software package. It contains five capacity expansion analysis options ranging from preliminary analysis tools based on screening curves and linear programming to sophisticated non-linear analysis tools utilizing a Generalized Benders' Decomposition algorithm and a Dynamic Programming algorithm. A stand alone, detailed probabilistic production costing algorithm is also available for prespecified expansion plan production cost and reliability analysis. The multiple EGEAS analysis options are incorporated into a single control analysis program allowing users to match the analysis options selected to a particular problem's requirements and complexity. At the same time, the implementation of a flexible modular and extendable data base common to all five analysis options simplifies data input and maintenance, and rules out input-related inconsistencies among the analysis options. The development and implementation of a detailed but nevertheless efficient probabilistic production costing algorithm made possible the addition to EGEAS of a number of advanced features. These features include maintenance scheduling, economy interchange and reserve sharing, storage and limited energy unit modeling as well as Non-Dispatchable Generation and Load Management analysis. Sensitivity, uncertainty and trade-off analyses are also available in EGEAS. The structure and capabilities of EGEAS as well as the results of a testing and validation effort exercise are presented in Volume 1. Volume 2 includes mathematical appendices and a detailed description of the three generating systems used for testing and validating EGEAS. Volume 3 is the User's Manual, Volume 4 the Programmer's Manual, Volume 5 the Validation Manual, and Volume 6 is the Installation Manual.

Fleck, W.; Charny, L.

1983-03-01

368

Electric Generation Expansion Analysis System. Volume 6. Installation manual. Final report  

SciTech Connect

EGEAS is a modular state-of-the-art capacity expansion software package. It contains five capacity expansion analysis options ranging from preliminary analysis tools based on screening curves and linear programming to sophisticated nonlinear analysis tools utilizing a Generalized Benders' Decomposition algorithm and a Dynamic Programming algorithm. A stand alone, detailed probabilistic production costing algorithm is also available for prespecified expansion plan production cost and reliability analysis. The multiple EGEAS analysis options are incorporated into a single control analysis program allowing users to match the analysis option selected to a particular problem's requirements and complexity. At the same time, the implementation of a flexible modular and extendable data base common to all five analysis options simplifies data input and maintenance, and rules out input-related inconsistencies among the analysis options. The development and implementation of a detailed but nevertheless efficient probabilistic production costing algorithm made possible the addition to EGEAS of a number of advanced features. These features include maintenance scheduling, economy interchange and reserve sharing, storage and limited energy unit modeling as well as Non-Dispatchable Generation and Load Management analysis. Sensitivity, uncertainty and trade-off analyses are also available in EGEAS. The structure and capabilities of EGEAS as well as the results of a testing and validation effort exercise are presented in Volume 1. Volume 2 includes mathematical appendices and a detailed description of the three generating systems used for testing and validating EGEAS. Volume 3 is the User's Manual, Volume 4 the Programmer's Manual, Volume 5 the Validation Manual, and Volume 6 is the Installation Manual.

Fleck, W.D.; Charny, L.

1984-03-01

369

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

NASA Astrophysics Data System (ADS)

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 ten 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.

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

2012-10-01

370

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

371

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

372

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

373

Radiation therapy: posterior segment complications.  

PubMed

Therapeutic radiation to the posterior segment of the eye is a common option for posterior segment tumors. Such tumors are often malignant, but sometimes, benign neoplasms are treated with ionizing radiation. Also, non-neoplastic intraocular lesions like wet age-related macular degeneration may be treated with radiotherapy. Orbital disease, both neoplastic lesions like optic nerve sheath meningioma and non-neoplastic entities like Graves' ophthalmopathy may be treated with radiotherapy and this may include radiation of the optic nerve and posterior segment of the eye. Occasionally, radiotherapy of extraocular malignant disease, involving, e.g. the paranasal sinuses, may cause significant radiation damage to the eye. Complications after radiation to the posterior segment of the eye are largely related to the radiation dose to the posterior segment. The amount of irradiated volume of normal tissue and fractionation are also important for the development of radiation complications to the posterior segment. Radiation retinopathy is the most common complication of the posterior segment, but radiation optic neuropathy also occurs frequently. Radiation scleral necrosis is less frequent probably due to the radioresistance of the scleral collagen. These complications have the potential to cause blindness (radiation retinopathy and optic neuropathy) or enucleation of the eye (scleral necrosis). Although numerous treatments have been advocated, management of radiation-induced damage remains controversial. Efficacy for any treatment still needs to be proven and, if possible, the best option by far is to minimize radiation changes to normal tissue. PMID:23989132

Seregard, Stefan; Pelayes, David E; Singh, Arun D

2013-01-01

374

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

375

Electric-Generation-Expansion Analysis System. Volume 5. Validation manual. Final report  

SciTech Connect

EGEAS, a modular state-of-the-art capacity expansion software package, contains five capacity expansion analysis options ranging from preliminary analysis tools based on screening curves and linear programming to sophisticated nonlinear analysis tools utilizing a Generalized Benders' Decomposition algorithm and a Dynamic Programming algorithm. A stand-alone, detailed probabilistic production costing algorithm is also available. The development and implementation of a efficient probabilistic production costing algorithm made possible the addition to EGEAS of a number of advanced features: maintenance scheduling, economy interchange and reserve sharing, storage and limited energy unit modeling as well as Non-Dispatchable Generation and Load Management analysis. Sensitivity, uncertainty and trade-off analyses are also available in EGEAS. The structure and capabilities of EGEAS as well as the results of a testing and validation effort exercise are presented in Volume 1. Volume 2 includes mathematical appendices and a detailed description of the three generating systems used for testing and validating EGEAS. Volume 3 is the User's Manual, Volume 4 the Programmer's Manual, Volume 5 the Validation Manual, and Volume 6 is the Installation Manual.

Fleck, W.D.; Charny, L.

1983-05-01

376

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

377

The biomechanical properties of the cornea and anterior segment parameters  

PubMed Central

Background To investigate the biomechanical properties of the cornea measured with the Ocular Response Analyzer (ORA) and their association with the anterior segment parameters representing the geometric dimensions including the corneal volume and anterior chamber volume. Methods A retrospective review of 1020 patients who visited the BGN Eye Clinic was done. The mean radius of the corneal curvature, corneal astigmatism, corneal volume, anterior chamber depth, and anterior chamber volume were measured with an anterior segment tomographer. The central corneal thickness (CCT) was measured with an ultrasonic pachymeter. The corneal diameter was measured with an Orbscan as White to White. Cornea hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOPg), and cornea-compensated IOP (IOPcc) were measured with an ORA. Multiple linear regression models were constructed with CH and CRF as the dependent variables and age, gender, and the anterior segment parameters as the covariates. Results 958 eyes from 958 patients (mean age 26.7 years; male 43.4%) were included in this study after excluding some eyes according to the exclusion criteria. The mean CH and CRF were 10.1 and 9.9 mmHg, respectively. The mean IOPg and IOPcc were 14.8 and 15.8 mmHg. The multivariate analysis showed that CH was negatively associated with the mean radius of the cornea curvature (regression coefficient?=?-?0.481, p?=?0.023) and positively associated with CCT (regression coefficient =0.015, p?volume (regression coefficient =0.059, p?=?0.014). The association between CH and the corneal diameter, anterior chamber depth, and anterior chamber volume were not statistically significant. The evaluation of CRF showed that CRF was negatively associated with the mean radius of the cornea curvature (regression coefficient?=?-?0.540, p?=?0.013), and positively associated with CCT (??=?0.026, p?volume, anterior chamber depth, and anterior chamber volume were not statistically significant. Conclusion The CH was shown to be positively associated with the corneal volume and the association between CH and the anterior chamber volume were not significant. The associations of CRF with the corneal volume or anterior chamber volume were not significant. PMID:24083664

2013-01-01

378

The Journal of Geometric Analysis Volume 7, Number 3, 1997  

E-print Network

by Mean Curvature,I: Convergence By Halil Mete Soner ABSTRACT. In this paper we study the asymptotic for Nonlinear Analysis. @ 1997 The Journal of Geometric Analysis ISSN 1050-6926 #12;438 Halil Mete Soner 1

Soner, Halil Mete

379

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

380

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

381

Underground Test Area Subproject Phase I Data Analysis Task. Volume VIII - Risk Assessment Documentation Package  

SciTech Connect

Volume VIII 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 risk assessment 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

382

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

383

Passive solar design handbook. Volume two of two volumes: passive solar design analysis  

SciTech Connect

A manual for the design and performance evaluation and analysis of passive solar heating systems is presented. Two passive solar building types are analyzed: direct gain and thermal storage walls. Rules of thumb for the schematic design phase and simplified procedures for the design development phase are described. Analysis methods for the construction documents phase are given. The design procedure for fan-forced rock beds for hybrid systems is presented. Economic analysis methods for passive solar buildings are described. Tables of monthly average solar radiation, temperature, and degree-days for various locations in the US and southern Canada are included. (WHK)

Balcomb, J.D.; Barley, D.; McFarland, R.; Perry, J. Jr.; Wray, W.; Noll, S.

1980-01-01

384

Analysis of Tidal Breathing Flow Volume Loops for Automated Lung-Function Diagnosis in Infants  

Microsoft Academic Search

Lung-function analysis in the age group below 5 years has not yet found its way into clinical routine. One possible candidate for routine lung testing in this age group is the analysis of tidal breathing flow-volume (TBFV) loops, a technique that has not yet proven to be capable of detecting obstructive and other lung disorders at an early stage. We

Steffen Leonhardt; Peter Ahrens; Vojislav Kecman

2010-01-01

385

Bivariate analysis of flood peaks and volumes using copulas. An application to the Danube River  

NASA Astrophysics Data System (ADS)

A multivariate analysis on flood variables such as flood peaks, volumes and durations, is essential for hydrotechnical projects design. A lot of authors have suggested the use of bivariate distributions for the frequency analysis of flood peaks and volumes due to the supposition that the marginal probability distribution type is the same for these variables. The application of Copulas, which are becoming gradually widespread, can overcome this constraint. The selection of the appropriate copula type/families is not extensively treated in the literature and it remains a challenge in copula analysis. In this study a bivariate copula analysis with the use of different copula families is carried out on the basis of flood peak and the corresponding volumes along a river. This bivariate analysis of flood peaks and volumes is based on streamflow daily data of a time-series more than 100 years from several gauged stations of the Danube River. The methodology applied using annual maximum flood peaks (AMF) with the independent annual maximum volumes of fixed durations at 5, 10, 15,20,25,30 and 60 days. The discharge-volume pairs correlation are examined using Kendall's tau correlation analysis. The copulas families that selected for the bivariate modeling of the extracted pairs discharge and volumes are the Archimedean, Extreme-value and other copula families. The evaluation of the copulas performance achieved with the use of scatterplots of the observed and bootstrapped simulated pairs and formal tests of goodness of fit. Suitability of copulas was statistically compared. Archimedean (e.g. Frank and Clayton) copulas revealed to be more capable for bivariate modeling of floods than the other examined copula families at the Danube River. Results showed in general that copulas are effective tools for bivariate modeling of the two study random variables.

Papaioannou, George; Bacigal, Tomas; Jeneiova, Katarina; Kohnová, Silvia; Szolgay, Jan; Loukas, Athanasios

2014-05-01

386

Thermal characterization and analysis of microliter liquid volumes using the three-omega method  

NASA Astrophysics Data System (ADS)

Thermal phenomena in many biological systems offer an alternative detection opportunity for quantifying relevant sample properties. While there is substantial prior work on thermal characterization methods for fluids, the push in the biology and biomedical research communities towards analysis of reduced sample volumes drives a need to extend and scale these techniques to these volumes of interest, which can be below 100 pl. This work applies the 3? technique to measure the temperature-dependent thermal conductivity and heat capacity of de-ionized water, silicone oil, and salt buffer solution droplets from 24 to 80 °C. Heater geometries range in length from 200 to 700 ?m and in width from 2 to 5 ?m to accommodate the size restrictions imposed by small volume droplets. We use these devices to measure droplet volumes of 2 ?l and demonstrate the potential to extend this technique down to pl droplet volumes based on an analysis of the thermally probed volume. Sensitivity and uncertainty analyses provide guidance for relevant design variables for characterizing properties of interest by investigating the tradeoffs between measurement frequency regime, device geometry, and substrate material. Experimental results show that we can extract thermal conductivity and heat capacity with these sample volumes to within less than 1% of thermal properties reported in the literature.

Roy-Panzer, Shilpi; Kodama, Takashi; Lingamneni, Srilakshmi; Panzer, Matthew A.; Asheghi, Mehdi; Goodson, Kenneth E.

2015-02-01

387

Robust parallel clustering algorithm for image segmentation  

NASA Astrophysics Data System (ADS)

This paper describes a hierarchical parallel implementation of two clustering algorithms applied to the segmentation of multidimensional images and range images. The proposed hierarchical parallel implementation results in a fast robust segmentation algorithm that can be applied in a number of practical computer vision problems. The clustering process is divided in two basic steps. First, a fast sequential clustering algorithm performs a simple analysis of the image data, which results in a sub optimal classification of the image features. Second, the resulting clusters are analyzed using the minimum volume ellipsoid estimator. The second step is to merge the similar clusters using the number and shape of the ellipsoidal clusters that best represents the data. Both algorithms are implemented in a parallel computer architecture that speeds up the classification task. The hierarchical clustering algorithm is compared against the fuzzy k-means clustering algorithm showing that both approaches gave comparable segmentation results. The hierarchical parallel implementation is tested in synthetic multidimensional images and real range images.

Tamez-Pena, Jose G.; Perez, Arnulfo

1996-02-01

388

Computational analysis of blood volume curves and risk of intradialytic morbid events in hemodialysis  

Microsoft Academic Search

Computational analysis of blood volume curves and risk of intradialytic morbid events in hemodialysis.BackgroundBlood volume (BV) curves have been used to prevent intradialytic morbid events (IMEs) caused by hypotensive episodes in hemodialysis treatment. However, no standardized parameter is available to describe BV dynamics and to enable online interference with ultrafiltration rates in unselected patients. Moreover, only time-dependent BV reduction and

Joachim Beige; Jeremiah Sone; Arya M. Sharma; Martin Rudwaleit; Gerd Offermann; Armin Distler; Lothar Preuschof

2000-01-01

389

Satellite power systems (SPS) concept definition study. Volume 7: SPS program plan and economic analysis, appendixes  

NASA Technical Reports Server (NTRS)

Three appendixes in support of Volume 7 are contained in this document. The three appendixes are: (1) Satellite Power System Work Breakdown Structure Dictionary; (2) SPS cost Estimating Relationships; and (3) Financial and Operational Concept. Other volumes of the final report that provide additional detail are: Executive Summary; SPS Systems Requirements; SPS Concept Evolution; SPS Point Design Definition; Transportation and Operations Analysis; and SPS Technology Requirements and Verification.

Hanley, G.

1978-01-01

390

Genetic and Cytogenetic Analysis of the 43AE Region Containing the Segment Polarity Gene costa and the Cellular Polarity Genes prickle and spiny-legs in Drosophila melanogaster  

Microsoft Academic Search

A cytogenetic analysis of the 43A-E region of chromosome 2 in Drosophila melanogaster is presented. Within this interval 27 complementation groups have been identified by extensive F2 screens and ordered by deletion mapping. The region includes the cellular polarity genes prickle and spiny-legs, the segmentation genes costa and torso, the morphogenetic locus sine oculis and is bounded on its distal

Pascal Heitzler; Darin Coulson; Maria-Theresa Saenz-Robles; Michael Ashburner; John Roote; Pat Simpson; David Gubbt

391

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

392

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

393

Combined Biomarker Analysis for Risk of Acute Kidney Injury in Patients with ST-Segment Elevation Myocardial Infarction  

PubMed Central

Background Acute kidney injury (AKI) complicating ST-segment elevation myocardial infarction (STEMI) increases subsequent morbidity and mortality. We combined the biomarkers of heart failure (HF; B-type natriuretic peptide [BNP] and soluble ST2 [sST2]) and renal injury (NGAL [neutrophil gelatinase-associated lipocalin] and cystatin C) in predicting the development of AKI in patients with STEMI undergoing primary percutaneous coronary intervention (PCI). Methods and Results From March 2010 to September 2013, 189 STEMI patients were sequentially enrolled and serum samples were collected at presentation for BNP, sST2, NGAL and cystatin C analysis. 37 patients (19.6%) developed AKI of varying severity within 48 hours of presentation. Univariate analysis showed age, Killip class ?2, hypertension, white blood cell counts, hemoglobin, estimated glomerular filtration rate, blood urea nitrogen, creatinine, and all the four biomarkers were predictive of AKI. Serum levels of the biomarkers were correlated with risk of AKI and the Acute Kidney Injury Network (AKIN) stage and all significantly discriminated AKI (area under the receiver operating characteristic [ROC] curve: BNP: 0.86, sST2: 0.74, NGAL: 0.75, cystatin C: 0.73; all P < 0.05). Elevation of ?2 of the biomarkers higher than the cutoff values derived from the ROC analysis improved AKI risk stratification, regardless of the creatine level (creatinine < 1.24 mg/dL: odds ratio [OR] 11.25, 95% confidence interval [CI] 1.63-77.92, P = 0.014; creatinine ? 1.24: OR 15.0, 95% CI 1.23-183.6, P = 0.034). Conclusions In this study of STEMI patients undergoing primary PCI, the biomarkers of heart failure (BNP and sST2) and renal injury (NGAL and cystatin C) at presentation were predictive of AKI. High serum levels of the biomarkers were associated with an elevated risk and more advanced stage of AKI. Regardless of the creatinine level, elevation of ?2 of the biomarkers higher than the cutoff values indicated a further rise in AKI risk. Combined biomarker approach may assist in risk stratification of AKI in patients with STEMI. PMID:25853556

Tung, Ying-Chang; Chang, Chih-Hsiang; Chen, Yung-Chang; Chu, Pao-Hsien

2015-01-01

394

Experimental focal neocortical epilepsy is associated with reduced white matter volume growth: results from multiparametric MRI analysis.  

PubMed

Focal epilepsy has recently been associated with remote white matter damage, including reduced white matter volume. Longitudinal assessment of these white matter changes, in relation to functional mechanisms and consequences, may be ideally done by in vivo neuroimaging in well-controlled experimental animal models. We assessed whether advanced machine learning algorithm models could accurately detect volumetric changes in white matter from multiparametric MR images, longitudinally collected in a neocortical focal epilepsy rat model. We measured classification accuracy in two supervised segmentation models: i.e. the generalized linear model and the nonlinear random forest model-by comparing computed white matter probabilities with actual neuroanatomically identified white matter. We found excellent overall discriminatory power for both models. However, the random forest model demonstrated a superior goodness-of-fit calibration plot that was close to the ideal calibration line. Based on this model, we measured that total white matter volume increased in young adult control and epileptic rats over a period of 10 weeks, but the average white matter volume was significantly lower in the focal epilepsy group. Changes in gray matter volume were not significantly different between control and epileptic rats. Our results (1) indicate that recurrent spontaneous seizures have an adverse effect on global white matter growth and (2) show that individual whole brain white matter volume can be accurately determined using a combination of multiparametric MRI and supervised segmentation models, offering a powerful tool to assess white matter volume changes in preclinical studies of neurological disease. PMID:24013878

Otte, Willem M; van Meer, Maurits P A; van der Marel, Kajo; Zwartbol, René; Viergever, Max A; Braun, Kees P J; Dijkhuizen, Rick M

2015-01-01

395

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

396

Comparison of retinal thickness by Fourier-domain optical coherence tomography and OCT retinal image analysis software segmentation analysis derived from Stratus optical coherence tomography images  

PubMed Central

Purpose: To compare thickness measurements between Fourier-domain optical coherence tomography (FD-OCT) and time-domain OCT images analyzed with a custom-built OCT retinal image analysis software (OCTRIMA). Methods: Macular mapping (MM) by StratusOCT and MM5 and MM6 scanning protocols by an RTVue-100 FD-OCT device are performed on 11 subjects with no retinal pathology. Retinal thickness (RT) and the thickness of the ganglion cell complex (GCC) obtained with the MM6 protocol are compared for each early treatment diabetic retinopathy study (ETDRS)-like region with corresponding results obtained with OCTRIMA. RT results are compared by analysis of variance with Dunnett post hoc test, while GCC results are compared by paired t-test. Results: A high correlation is obtained for the RT between OCTRIMA and MM5 and MM6 protocols. In all regions, the StratusOCT provide the lowest RT values (mean difference 43 ± 8 ?m compared to OCTRIMA, and 42 ± 14 ?m compared to RTVue MM6). All RTVue GCC measurements were significantly thicker (mean difference between 6 and 12 ?m) than the GCC measurements of OCTRIMA. Conclusion: High correspondence of RT measurements is obtained not only for RT but also for the segmentation of intraretinal layers between FD-OCT and StratusOCT-derived OCTRIMA analysis. However, a correction factor is required to compensate for OCT-specific differences to make measurements more comparable to any available OCT device. PMID:21639572

Tátrai, Erika; Ranganathan, Sudarshan; Ferencz, Mária; DeBuc, Delia Cabrera; Somfai, Gábor Márk

2011-01-01

397

Comparison of retinal thickness by Fourier-domain optical coherence tomography and OCT retinal image analysis software segmentation analysis derived from Stratus optical coherence tomography images  

NASA Astrophysics Data System (ADS)

Purpose: To compare thickness measurements between Fourier-domain optical coherence tomography (FD-OCT) and time-domain OCT images analyzed with a custom-built OCT retinal image analysis software (OCTRIMA). Methods: Macular mapping (MM) by StratusOCT and MM5 and MM6 scanning protocols by an RTVue-100 FD-OCT device are performed on 11 subjects with no retinal pathology. Retinal thickness (RT) and the thickness of the ganglion cell complex (GCC) obtained with the MM6 protocol are compared for each early treatment diabetic retinopathy study (ETDRS)-like region with corresponding results obtained with OCTRIMA. RT results are compared by analysis of variance with Dunnett post hoc test, while GCC results are compared by paired t-test. Results: A high correlation is obtained for the RT between OCTRIMA and MM5 and MM6 protocols. In all regions, the StratusOCT provide the lowest RT values (mean difference 43 +/- 8 ?m compared to OCTRIMA, and 42 +/- 14 ?m compared to RTVue MM6). All RTVue GCC measurements were significantly thicker (mean difference between 6 and 12 ?m) than the GCC measurements of OCTRIMA. Conclusion: High correspondence of RT measurements is obtained not only for RT but also for the segmentation of intraretinal layers between FD-OCT and StratusOCT-derived OCTRIMA analysis. However, a correction factor is required to compensate for OCT-specific differences to make measurements more comparable to any available OCT device.

Tátrai, Erika; Ranganathan, Sudarshan; Ferencz, Mária; Debuc, Delia Cabrera; Somfai, Gábor Márk

2011-05-01

398

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

399

BAC-Pool Sequencing and Analysis of Large Segments of A12 and D12 Homoeologous Chromosomes in Upland Cotton  

PubMed Central

Although new and emerging next-generation sequencing (NGS) technologies have reduced sequencing costs significantly, much work remains to implement them for de novo sequencing of complex and highly repetitive genomes such as the tetraploid genome of Upland cotton (Gossypium hirsutum L.). Herein we report the results from implementing a novel, hybrid Sanger/454-based BAC-pool sequencing strategy using minimum tiling path (MTP) BACs from Ctg-3301 and Ctg-465, two large genomic segments in A12 and D12 homoeologous chromosomes (Ctg). To enable generation of longer contig sequences in assembly, we implemented a hybrid assembly method to process ~35x data from 454 technology and 2.8-3x data from Sanger method. Hybrid assemblies offered higher sequence coverage and better sequence assemblies. Homology studies revealed the presence of retrotransposon regions like Copia and Gypsy elements in these contigs and also helped in identifying new genomic SSRs. Unigenes were anchored to the sequences in Ctg-3301 and Ctg-465 to support the physical map. Gene density, gene structure and protein sequence information derived from protein prediction programs were used to obtain the functional annotation of these genes. Comparative analysis of both contigs with Arabidopsis genome exhibited synteny and microcollinearity with a conserved gene order in both genomes. This study provides insight about use of MTP-based BAC-pool sequencing approach for sequencing complex polyploid genomes with limited constraints in generating better sequence assemblies to build reference scaffold sequences. Combining the utilities of MTP-based BAC-pool sequencing with current longer and short read NGS technologies in multiplexed format would provide a new direction to cost-effectively and precisely sequence complex plant genomes. PMID:24116150

Buyyarapu, Ramesh; Kantety, Ramesh V.; Yu, John Z.; Xu, Zhanyou; Kohel, Russell J.; Percy, Richard G.; Macmil, Simone; Wiley, Graham B.; Roe, Bruce A.; Sharma, Govind C.

2013-01-01

400

Price-volume cross-correlation analysis of CSI300 index futures  

NASA Astrophysics Data System (ADS)

We investigate the cross-correlation between price returns and trading volumes for the China Securities Index 300 (CSI300) index futures, which are the only stock index futures traded on the China Financial Futures Exchange (CFFEX). The basic statistics suggest that distributions of these two time series are not normal but exhibit fat tails. Based on the detrended cross-correlation analysis (DCCA), we obtain that returns and trading volumes are long-range cross-correlated. The existence of multifractality in the cross-correlation between returns and trading volumes has been proven with the multifractal detrended cross-correlation analysis (MFDCCA) algorithm. The multifractal analysis also confirms that returns and trading volumes have different degrees of multifractality. We further perform a cross-correlation statistic to verify whether the cross-correlation significantly exists between returns and trading volumes for CSI300 index futures. In addition, results of the test for lead-lag effect demonstrate that contemporaneous cross-correlation of return and trading volume series is stronger than cross-correlations of leaded or lagged series.

Wang, Dong-Hua; Suo, Yuan-Yuan; Yu, Xiao-Wen; Lei, Man

2013-03-01

401

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

402

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

403

Accounting for segment correlations in segmented gamma-ray scans  

SciTech Connect

In a typical segmented gamma-ray scanner (SGS), the detector`s field of view is collimated so that a complete horizontal slice or segment of the desired thickness is visible. Ordinarily, the collimator is not deep enough to exclude gamma rays emitted from sample volumes above and below the segment aligned with the collimator. This can lead to assay biases, particularly for certain radioactive-material distributions. Another consequence of the collimator`s low aspect ratio is that segment assays at the top and bottom of the sample are biased low because the detector`s field of view is not filled. This effect is ordinarily countered by placing the sample on a low-Z pedestal and scanning one or more segment thicknesses below and above the sample. This takes extra time, however, We have investigated a number of techniques that both account for correlated segments and correct for end effects in SGS assays. Also, we have developed an algorithm that facilitates estimates of assay precision. Six calculation methods have been compared by evaluating the results of thousands of simulated, assays for three types of gamma-ray source distribution and ten masses. We will report on these computational studies and their experimental verification.

Sheppard, G.A.; Prettyman, T.H.; Piquette, E.C.

1994-08-01

404

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

405

Defining a rat blood pressure quantitative trait locus to a <81.8 kb congenic segment: comprehensive sequencing and renal transcriptome analysis  

PubMed Central

Evidence from multiple linkage and genome-wide association studies suggest that human chromosome 2 (HSA2) contains alleles that influence blood pressure (BP). Homologous to a large segment of HSA2 is rat chromosome 9 (RNO9), to which a BP quantitative trait locus (QTL) was previously mapped. The objective of the current study was to further resolve this BP QTL. Eleven congenic strains with introgressed segments spanning <81.8 kb to <1.33 Mb were developed by introgressing genomic segments of RNO9 from the Dahl salt-resistant (R) rat onto the genome of the Dahl salt-sensitive (S) rat and tested for BP. The congenic strain with the shortest introgressed segment spanning <81.8 kb significantly lowered BP of the hypertensive S rat by 25 mmHg and significantly increased its mean survival by 45 days. In contrast, two other congenic strains had increased BP compared with the S. We focused on the <81.8 kb congenic strain, which represents the shortest genomic segment to which a BP QTL has been mapped to date in any species. Sequencing of this entire region in both S and R rats detected 563 variants. The region did not contain any known or predicted rat protein coding genes. Furthermore, a whole genome renal transcriptome analysis between S and the <81.8 kb S.R congenic strain revealed alterations in several critical genes implicated in renal homeostasis. Taken together, our results provide the basis for future studies to examine the relationship between the candidate variants within the QTL region and the renal differentially expressed genes as potential causal mechanisms for BP regulation. PMID:20716646

Gopalakrishnan, K.; Saikumar, J.; Peters, C. G.; Kumarasamy, S.; Farms, P.; Yerga-Woolwine, S.; Toland, E. J.; Schnackel, W.; Giovannucci, D. R.

2010-01-01

406

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

407

Economic analysis of the space shuttle system, volume 1  

NASA Technical Reports Server (NTRS)

An economic analysis of the space shuttle system is presented. The analysis is based on economic benefits, recurring costs, non-recurring costs, and ecomomic tradeoff functions. The most economic space shuttle configuration is determined on the basis of: (1) objectives of reusable space transportation system, (2) various space transportation systems considered and (3) alternative space shuttle systems.

1972-01-01

408

Guidance for Environmental Background Analysis Volume III: Groundwater  

E-print Network

follow U.S. EPA's Guidance for the Data Quality Objectives Process and Guidance for Data Quality Assessment: Practical Methods for Data Analysis. Groundwater background analysis is an integral component to background should be reviewed and assessed during the initial phase of an investigation. The operational

409

Computerized detection of pulmonary embolism in computed tomographic pulmonary angiography (CTPA): improvement of vessel segmentation  

NASA Astrophysics Data System (ADS)

Vessel segmentation is a fundamental step in an automated pulmonary embolism (PE) detection system. The purpose of this study is to improve the segmentation scheme for pulmonary vessels affected by PE and other lung diseases. We have developed a multiscale hierarchical vessel enhancement and segmentation (MHES) method for pulmonary vessel tree extraction based on the analysis of eigenvalues of Hessian matrices. However, it is difficult to segment the pulmonary vessels accurately when the vessel is occluded by PEs and/or surrounded by lymphoid tissues or lung diseases. In this study, we developed a method that combines MHES with level set refinement (MHES-LSR) to improve vessel segmentation accuracy. The level set was designed to propagate the initial object contours to the regions with relatively high gray-level, high gradient, and high compactness as measured by the smoothness of the curvature along vessel boundaries. Two and eight CTPA scans were randomly selected as training and test data sets, respectively. Forty volumes of interest (VOI) containing "representative" vessels were manually segmented by a radiologist experienced in CTPA interpretation and used as reference standard. The results show that, for the 32 test VOIs, the average percentage volume error relative to the reference standard was improved from 31.7+/-10.9% using the MHES method to 7.7+/-4.7% using the MHES-LSR method. The correlation between the computer-segmented vessel volume and the reference standard was improved from 0.954 to 0.986. The accuracy of vessel segmentation was improved significantly (p<0.05). The MHES-LSR method may have the potential to improve PE detection.

Zhou, Chuan; Chan, Heang-Ping; Kuriakose, Jean W.; Chughtai, Aamer; Hadjiiski, Lubomir M.; Wei, Jun; Patel, Smita; Kazerooni, Ella A.

2011-03-01

410

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

411

Scram discharge volume break studies accident sequence analysis  

SciTech Connect

This paper is a summary of a report describing the predicted response of Unit 1 at the Tennessee Valley Authority (TVA) Browns Ferry Nuclear Plant to a hypothetical small break loss of coolant accident (SBLOCA) outside of containment. The accident studied would be initiated by a break in the scram discharge volume (SDV) piping when it is pressurized to full reactor vessel pressure as a normal consequence of a reactor scram. If the scram could be reset, the scram outlet valves would close to isolate the SDV and the piping break from the reactor vessel. However, reset is possible only if the conditions that caused the scram have cleared; it has been assumed in this study that the scram signal remains in effect over a long period of time.

Harrington, R.M.; Hodge, S.A.

1982-01-01

412

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

413

[Application of hair analysis of selected psychoactive substances for medico-legal purposes. Part I. Segmental hair analysis in cases of fatal opioids and amphetamines poisoning].  

PubMed

The present experimental investigations were inspired by the necessity of standardizing the procedures and analytical methods employed in hair analysis aiming at a retrospective evaluation of ingestion of various xenobiotics. Thus, in keeping with the principal premises, the main objective of the study was development of unique, novel chemico-toxicological procedures for analyzing hair content of psychoactive substances in two basic groups of substances of abuse: opioids (morphine, 6-monoacetylmorphine, codeine) and amphetamines (amphetamine, methamphetamine, MDA, MDMA, MDEA) by HPLC-APCI-MS-MS, followed by verification of the thus worked out procedures in medico-legal practice through opinionating in selected group of patients deceased due to fatal psychoactive substance poisoning (cause of death determination). Determinations of opioids and amphetamines in the hair biological matrix were performed using high performance liquid chromatography - atmospheric pressure chemical ionization - tandem mass spectrometry (HPLC-APCI-MS-MS). In the group of fatal poisonings by ,,Polish heroine", hair segmental analysis confirmed the abuse profile of the opiate or mixed (opiate-amphetamine) type, which to some measure is characteristic of Polish drug addiction, indicating the presence of these xenobiotics in the investigating hair samples in the premortem period. PMID:20860298

Rojek, Sebastian; K?ys, Ma?gorzata; Konopka, Tomasz

2009-01-01

414

Analysis of cell concentration, volume concentration, and colony size of Microcystis via laser particle analyzer.  

PubMed

The analysis of the cell concentration, volume concentration, and colony size of Microcystis is widely used to provide early warnings of the occurrence of blooms and to facilitate the development of predictive tools to mitigate their impact. This study developed a new approach for the analysis of the cell concentration, volume concentration, and colony size of Microcystis by applying a laser particle analyzer. Four types of Microcystis samples (55 samples in total) were analyzed by a laser particle analyzer and a microscope. By the application of the laser particle analyzer (1) when n = 1.40 and k = 0.1 (n is the intrinsic refractive index, whereas k is absorption of light by the particle), the results of the laser particle analyzer showed good agreement with the microscopic results for the obscuration indicator, volume concentration, and size distribution of Microcystis; (2) the Microcystis cell concentration can be calculated based on its linear relationship with obscuration; and (3) the volume concentration and size distribution of Microcystis particles (including single cells and colonies) can be obtained. The analytical processes involved in this new approach are simpler and faster compared to that by microscopic counting method. From the results, it was identified that the relationship between cell concentration and volume concentration depended on the colony size of Microcystis because the intercellular space was high when the colony size was high. Calculation of cell concentration and volume concentration may occur when the colony size information is sufficient. PMID:24570208

Li, Ming; Zhu, Wei; Gao, Li

2014-05-01

415

Analysis of Cell Concentration, Volume Concentration, and Colony Size of Microcystis Via Laser Particle Analyzer  

NASA Astrophysics Data System (ADS)

The analysis of the cell concentration, volume concentration, and colony size of Microcystis is widely used to provide early warnings of the occurrence of blooms and to facilitate the development of predictive tools to mitigate their impact. This study developed a new approach for the analysis of the cell concentration, volume concentration, and colony size of Microcystis by applying a laser particle analyzer. Four types of Microcystis samples (55 samples in total) were analyzed by a laser particle analyzer and a microscope. By the application of the laser particle analyzer (1) when n = 1.40 and k = 0.1 ( n is the intrinsic refractive index, whereas k is absorption of light by the particle), the results of the laser particle analyzer showed good agreement with the microscopic results for the obscuration indicator, volume concentration, and size distribution of Microcystis; (2) the Microcystis cell concentration can be calculated based on its linear relationship with obscuration; and (3) the volume concentration and size distribution of Microcystis particles (including single cells and colonies) can be obtained. The analytical processes involved in this new approach are simpler and faster compared to that by microscopic counting method. From the results, it was identified that the relationship between cell concentration and volume concentration depended on the colony size of Microcystis because the intercellular space was high when the colony size was high. Calculation of cell concentration and volume concentration may occur when the colony size information is sufficient.

Li, Ming; Zhu, Wei; Gao, Li

2014-05-01

416

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

417

Nucleotide Sequence Analysis of the M Genomic Segment of El Moro Canyon Hantavirus: Antigenic Distinction from Four Corners Hantavirus  

Microsoft Academic Search

El Moro Canyon hantavirus (ELMC, previously known as HMV-1) is associated with the western harvest mouse Reithrodontomys megalotis. The interpretation that ELMC is a novel hantavirus was based upon comparisons of the nucleotide sequence of the S genomic segment with those of other hantaviruses. We now show that the ELMC M genome, like the S genome, is genetically similar to

Norah Torrez-Martinez; Wanmin Song; Brian Hjelle

1995-01-01

418

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