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1

Automated segmentation and dose-volume analysis with DICOMautomaton  

NASA Astrophysics Data System (ADS)

Purpose: Exploration of historical data for regional organ dose sensitivity is limited by the effort needed to (sub-)segment large numbers of contours. A system has been developed which can rapidly perform autonomous contour sub-segmentation and generic dose-volume computations, substantially reducing the effort required for exploratory analyses. Methods: A contour-centric approach is taken which enables lossless, reversible segmentation and dramatically reduces computation time compared with voxel-centric approaches. Segmentation can be specified on a per-contour, per-organ, or per-patient basis, and can be performed along either an embedded plane or in terms of the contour's bounds (e.g., split organ into fractional-volume/dose pieces along any 3D unit vector). More complex segmentation techniques are available. Anonymized data from 60 head-and-neck cancer patients were used to compare dose-volume computations with Varian's EclipseTM (Varian Medical Systems, Inc.). Results: Mean doses and Dose-volume-histograms computed agree strongly with Varian's EclipseTM. Contours which have been segmented can be injected back into patient data permanently and in a Digital Imaging and Communication in Medicine (DICOM)-conforming manner. Lossless segmentation persists across such injection, and remains fully reversible. Conclusions: DICOMautomaton allows researchers to rapidly, accurately, and autonomously segment large amounts of data into intricate structures suitable for analyses of regional organ dose sensitivity.

Clark, H.; Thomas, S.; Moiseenko, V.; Lee, R.; Gill, B.; Duzenli, C.; Wu, J.

2014-03-01

2

Early Expansion of the Intracranial CSF Volume After Palliative Whole-Brain Radiotherapy: Results of a Longitudinal CT Segmentation Analysis  

SciTech Connect

Purpose: To assess cerebral atrophy after radiotherapy, we measured intracranial cerebrospinal fluid volume (ICSFV) over time after whole-brain radiotherapy (WBRT) and compared it with published normal-population data. Methods and Materials: We identified 9 patients receiving a single course of WBRT (30 Gy in 10 fractions over 2 weeks) for ipsilateral brain metastases with at least 3 years of computed tomography follow-up. Segmentation analysis was confined to the tumor-free hemi-cranium. The technique was semiautomated by use of thresholds based on scanned image intensity. The ICSFV percentage (ratio of ICSFV to brain volume) was used for modeling purposes. Published normal-population ICSFV percentages as a function of age were used as a control. A repeated-measures model with cross-sectional (between individuals) and longitudinal (within individuals) quadratic components was fitted to the collected data. The influence of clinical factors including the use of subependymal plate shielding was studied. Results: The median imaging follow-up was 6.25 years. There was an immediate increase (p < 0.0001) in ICSFV percentage, which decelerated over time. The clinical factors studied had no significant effect on the model. Conclusions: WBRT immediately accelerates the rate of brain atrophy. This longitudinal study in patients with brain metastases provides a baseline against which the potential benefits of more localized radiotherapeutic techniques such as radiosurgery may be compared.

Sanghera, Paul [Odette Cancer Centre, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); University Hospital Birmingham, Edgbaston, Birmingham (United Kingdom); Gardner, Sandra L. [Odette Cancer Centre, Toronto, Ontario (Canada); Department of Public Health Sciences, University of Toronto, Toronto, Ontario (Canada); Scora, Daryl [R. S. McLaughlin Durham Regional Cancer Centre, Oshawa, Ontario (Canada); Davey, Phillip, E-mail: phil.davey@sunnybrook.c [Odette Cancer Centre, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada)

2010-03-15

3

Segmentation strategies for polymerized volume data sets  

E-print Network

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

Doddapaneni, Venkata Purna

2006-04-12

4

Cerebral Blood Volume Analysis in Glioblastomas Using Dynamic Susceptibility Contrast-Enhanced Perfusion MRI: A Comparison of Manual and Semiautomatic Segmentation Methods  

PubMed Central

Purpose To compare the reproducibilities of manual and semiautomatic segmentation method for the measurement of normalized cerebral blood volume (nCBV) using dynamic susceptibility contrast-enhanced (DSC) perfusion MR imaging in glioblastomas. Materials and Methods Twenty-two patients (11 male, 11 female; 27 tumors) with histologically confirmed glioblastoma (WHO grade IV) were examined with conventional MR imaging and DSC imaging at 3T before surgery or biopsy. Then nCBV (means and standard deviations) in each mass was measured using two DSC MR perfusion analysis methods including manual and semiautomatic segmentation method, in which contrast-enhanced (CE)-T1WI and T2WI were used as structural imaging. Intraobserver and interobserver reproducibility were assessed according to each perfusion analysis method or each structural imaging. Interclass correlation coefficient (ICC), Bland-Altman plot, and coefficient of variation (CV) were used to evaluate reproducibility. Results Intraobserver reproducibilities on CE-T1WI and T2WI were ICC of 0.74–0.89 and CV of 20.39–36.83% in manual segmentation method, and ICC of 0.95–0.99 and CV of 8.53–16.19% in semiautomatic segmentation method, repectively. Interobserver reproducibilites on CE-T1WI and T2WI were ICC of 0.86–0.94 and CV of 19.67–35.15% in manual segmentation method, and ICC of 0.74–1.0 and CV of 5.48–49.38% in semiautomatic segmentation method, respectively. Bland-Altman plots showed a good correlation with ICC or CV in each method. The semiautomatic segmentation method showed higher intraobserver and interobserver reproducibilities at CE-T1WI-based study than other methods. Conclusion The best reproducibility was found using the semiautomatic segmentation method based on CE-T1WI for structural imaging in the measurement of the nCBV of glioblastomas. PMID:23950891

Jung, Seung Chai; Choi, Seung Hong; Yeom, Jeong A.; Kim, Ji-Hoon; Ryoo, Inseon; Kim, Soo Chin; Shin, Hwaseon; Lee, A. Leum; Yun, Tae Jin; Park, Chul-Kee; Sohn, Chul-Ho; Park, Sung-Hye

2013-01-01

5

Multiple layer segmentation and analysis in three-dimensional spectral-domain optical coherence tomography volume scans.  

PubMed

Spectral-domain optical coherence tomography (SD-OCT) is a three-dimensional imaging technique that allows direct visualization of retinal morphology and architecture. The various retinal layers may be affected differentially by various diseases. An automated graph search algorithm is developed to sequentially segment 11 retinal surfaces in SD-OCT volumes using a three-stage approach. In stage 1, the four most easily discernible and/or distinct surfaces are identified in four-times-downsampled images and are used as a priori information to limit the graph search for the other surfaces in stage 2. Eleven surfaces were then detected in two-times-downsampled images in stage 2, and refined in the original images in stage 3 using the graph search integrating the estimated morphological shape models. Twenty macular SD-OCT volume scans from 20 normal subjects are used in this initial study. The overall mean and absolute mean differences in border positions between the automated and manual segmentation for the 11 surfaces are -0.20 ± 0.53 voxels (-0.76 ± 2.06 ?m) and 0.82 ± 0.64 voxels (3.19 ± 2.46 ?m), respectively. Intensity/reflectivity and thickness properties in various retinal layers are also investigated. This investigation in normal subjects may provide a comparative reference for subsequent adaptations in eyes with diseases. PMID:23843084

Hu, Zhihong; Wu, Xiaodong; Hariri, Amirhossein; Sadda, Srinivas R

2013-07-01

6

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

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

7

Automatic segmentation of the coronary artery in MSCT volume data  

NASA Astrophysics Data System (ADS)

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 scanned by multiple slices computed tomography (MSCT), an automatic segmentation algorithm is proposed. Firstly, detect and recognize the multiple seed points of the coronary artery in the scale space automatically from the 3D complex cardiac image datasets. Secondly, an improved layer region growing algorithm oriented to 3D tubular structure tissues is proposed to segment the coronary artery. Experiments show that the algorithm can extract coronary artery vessels effectively, which can improve the automation of coronary artery analysis, thus improve physicians' work efficiency.

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

2009-10-01

8

SEGMENTATION STRATEGIES FOR POLYMERIZED VOLUME DATA SETS PURNA DODDAPANENI  

E-print Network

SEGMENTATION STRATEGIES FOR POLYMERIZED VOLUME DATA SETS A Thesis by PURNA DODDAPANENI Submitted FOR POLYMERIZED VOLUME DATA SETS A Thesis by PURNA DODDAPANENI Submitted to Texas A&M University in partial Strategies for Polymerized Volume Data Sets (December 2004) Purna Chandra Rao Doddapaneni, B.Tech., Indian

9

Interobserver variation in clinical target volume and organs at risk segmentation in post-parotidectomy radiotherapy: can segmentation protocols help?  

PubMed Central

Objective : A study of interobserver variation in the segmentation of the post-operative clinical target volume (CTV) and organs at risk (OARs) for parotid tumours was undertaken. The segmentation exercise was performed as a baseline, and repeated after 3 months using a segmentation protocol to assess whether CTV conformity improved. Methods : Four head and neck oncologists independently segmented CTVs and OARs (contralateral parotid, spinal cord and brain stem) on CT data sets of five patients post parotidectomy. For each CTV or OAR delineation, total volume was calculated. The conformity level (CL) between different clinicians' outlines was measured using a validated outline analysis tool. The data for CTVs were reaanalysed after using the cochlear sparing therapy and conventional radiation segmentation protocol. Results : Significant differences in CTV morphology were observed at baseline, yielding a mean CL of 30% (range 25–39%). The CL improved after using the segmentation protocol with a mean CL of 54% (range 50–65%). For OARs, the mean CL was 60% (range 53–68%) for the contralateral parotid gland, 23% (range 13–27%) for the brain stem and 25% (range 22–31%) for the spinal cord. Conclusions There was low conformity for CTVs and OARs between different clinicians. The CL for CTVs improved with use of a segmentation protocol, but the CLs remained lower than expected. This study supports the need for clear guidelines for segmentation of target and OARs to compare and interpret the results of head and neck cancer radiation studies. PMID:22815423

Mukesh, M; Benson, R; Jena, R; Hoole, A; Roques, T; Scrase, C; Martin, C; Whitfield, G A; Gemmill, J; Jefferies, S

2012-01-01

10

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.

Tohka, Jussi

2014-01-01

11

Uterine fibroid segmentation and volume measurement on MRI  

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

12

Tumor volume measurement for nasopharyngeal carcinoma using knowledge-based fuzzy clustering MRI segmentation  

NASA Astrophysics Data System (ADS)

A knowledge-based fuzzy clustering (KBFC) MRI segmentation algorithm was proposed to obtain accurate tumor segmentation for tumor volume measurement of nasopharyngeal carcinoma (NPC). An initial segmentation was performed on T1 and contrast enhanced T1 MR images using a semi-supervised fuzzy c-means (SFCM) algorithm. Then, three types of anatomic and space knowledge--symmetry, connectivity and cluster center were used for image analysis which contributed the final tumor segmentation. After the segmentation, tumor volume was obtained by multi-planimetry method. Visual and quantitative validations were performed on phantom model and six data volumes of NPC patients, compared with ground truth (GT) and the results acquired using seeds growing (SG) for tumor segmentation. In visual format, KBFC showed better tumor segmentation image than SG. In quantitative segmentation quality estimation, on phantom model, the matching percent (MP) / correspondence ratio (CR) was 94.1-96.4% / 0.888-0.925 for KBFC and 94.1-96.0% / 0.884-0.918 for SG while on patient data volumes, it was 92.1+/- 2.6% / 0.884+/- 0.014 for KBFC and 87.4+/- 4.3% / 0.843+/- 0.041 for SG. In tumor volume measurement, on phantom model, measurement error was 4.2-5.0% for KBFC and 4.8-6.1% for SG while on patient data volumes, it was 6.6+/- 3.5% for KBFC and 8.8+/- 5.4% for SG. Based on these results, KBFC could provide high quality of MRI tumor segmentation for tumor volume measurement of NPC.

Zhou, Jiayin; Lim, Tuan-Kay; Chong, Vincent

2002-05-01

13

A generic video analysis and segmentation system  

Microsoft Academic Search

A generic video analysis system for supervised and unsupervised segmentation is described. The idea behind the presented concept is to integrate different advanced segmentation techniques to obtain a robust, efficient and modular segmentation system for natural video and still images. The system entails several independent modules. Each one of these modules encapsulates a complete video processing technique The intermediate results

Ebroul Izquierdo; Jianhui Xia; Roland Mech

2002-01-01

14

Active surface segmentation analysis of CCAT  

NASA Astrophysics Data System (ADS)

The Cornell Caltech Atacama Sub-millimeter Telescope (CCAT) is proposed to have 25m-diameter primary segmented active surface capable of diffraction-limited operation in the wavelength range between 200 microns to 1mm. The active surface design layout is composed of 162 "pie-shaped" segments, each fitted with three actuators that provide piston and tilt/tip control for segment positioning and orientation. We present a performance analysis for five types of segment positioning errors, e.g., piston, tilt/tips, radial and azimuth displacements, and twist errors. From these only the first two, segment piston and tilt/tip errors, are directly controllable by the actuator system. Segment tilt/tip motions may indirectly compensate radial and azimuth segment positioning errors. Residual segment twists introduce quadric phase distribution errors across the face of the segments that cannot be compensated by a simple 3-actuator/segment active surface control system. We have obtained Ruze's coefficients that relate the standard deviation of each segment positioning error type with the overall Strehl ratio of the telescope at 200 microns.

Cortés-Medellín, Germán

2006-06-01

15

Fully automated segmentation of oncological PET volumes using a combined multiscale and statistical model  

SciTech Connect

The widespread application of positron emission tomography (PET) in clinical oncology has driven this imaging technology into a number of new research and clinical arenas. Increasing numbers of patient scans have led to an urgent need for efficient data handling and the development of new image analysis techniques to aid clinicians in the diagnosis of disease and planning of treatment. Automatic quantitative assessment of metabolic PET data is attractive and will certainly revolutionize the practice of functional imaging since it can lower variability across institutions and may enhance the consistency of image interpretation independent of reader experience. In this paper, a novel automated system for the segmentation of oncological PET data aiming at providing an accurate quantitative analysis tool is proposed. The initial step involves expectation maximization (EM)-based mixture modeling using a k-means clustering procedure, which varies voxel order for initialization. A multiscale Markov model is then used to refine this segmentation by modeling spatial correlations between neighboring image voxels. An experimental study using an anthropomorphic thorax phantom was conducted for quantitative evaluation of the performance of the proposed segmentation algorithm. The comparison of actual tumor volumes to the volumes calculated using different segmentation methodologies including standard k-means, spatial domain Markov Random Field Model (MRFM), and the new multiscale MRFM proposed in this paper showed that the latter dramatically reduces the relative error to less than 8% for small lesions (7 mm radii) and less than 3.5% for larger lesions (9 mm radii). The analysis of the resulting segmentations of clinical oncologic PET data seems to confirm that this methodology shows promise and can successfully segment patient lesions. For problematic images, this technique enables the identification of tumors situated very close to nearby high normal physiologic uptake. The use of this technique to estimate tumor volumes for assessment of response to therapy and to delineate treatment volumes for the purpose of combined PET/CT-based radiation therapy treatment planning is also discussed.

Montgomery, David W. G.; Amira, Abbes; Zaidi, Habib [School of Electronics, Electrical Engineering and Computer Science, ECIT, The Queen's University of Belfast, Belfast, Northern Ireland (United Kingdom); School of Engineering and Design, Brunel University, London, Uxbridge (United Kingdom); Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva 4 (Switzerland)

2007-02-15

16

Artificial Neural Network-Based System for PET Volume Segmentation  

PubMed Central

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

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

2010-01-01

17

The evaluation of a highly automated mixture model based technique for PET tumor volume segmentation  

NASA Astrophysics Data System (ADS)

PET-based tumor volume segmentation techniques are under investigation in recent years due to the increased utilization of FDG-PET imaging in radiation therapy. We have taken the approach of using a Gaussian mixture model (GMM) to model the image intensity distribution of a selected 3D region that completely covers the tumor, called the "analysis region". The modeling is performed with a predetermined number of Gaussian classes and results in a classification of every voxel into one of these classes. The classes are then grouped together to obtain the tumor volume. The only user interaction required is the selection of the "analysis region" and then the algorithm proceeds automatically to initialize the parameters of the different classes and finds the maximum likelihood estimate with expectation maximization. We used 13 clinical and 19 phantom cases to evaluate the precision and accuracy of the segmentation. Reproducibility was within 10% of the average tumor volume estimate and accuracy was +/-35% of the true tumor volume and better when compared to two other proposed techniques. The GMM segmentation is extremely user friendly with good precision and accuracy. It has shown great potential to be used in the clinical environment.

Aristophanous, Michalis; Pelizzari, Charles A.

2008-03-01

18

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

PubMed

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

Zou, Yongning; Wang, Jue; Li, Jianwei

2013-01-01

19

Generic texture analysis applied to newspaper segmentation  

Microsoft Academic Search

This paper deals with the segmentation of grey-scale newspaper images into the distinct regions of text, picture and background. Feature vectors are obtained from the image by analysing localised textual characteristics and textual variation. Analysis is performed in a generic way making few contextual assumptions. The contrast, size, orientation and resolution of the image are accounted for by a combination

Paul Stefan Williams; Mike D. Alder

1996-01-01

20

Semiautomatic Regional Segmentation to Measure Orbital Fat Volumes in Thyroid-Associated Ophthalmopathy  

PubMed Central

Summary This study was designed to validate a novel semi-automated segmentation method to measure regional intra-orbital fat tissue volume in Graves' ophthalmopathy. Twenty-four orbits from 12 patients with Graves' ophthalmopathy, 24 orbits from 12 controls, ten orbits from five MRI study simulations and two orbits from a digital model were used. Following manual region of interest definition of the orbital volumes performed by two operators with different levels of expertise, an automated procedure calculated intra-orbital fat tissue volumes (global and regional, with automated definition of four quadrants). In patients with Graves' disease, clinical activity score and degree of exophthalmos were measured and correlated with intra-orbital fat volumes. Operator performance was evaluated and statistical analysis of the measurements was performed. Accurate intra-orbital fat volume measurements were obtained with coefficients of variation below 5%. The mean operator difference in total fat volume measurements was 0.56%. Patients had significantly higher intra-orbital fat volumes than controls (p<0.001 using Student's t test). Fat volumes and clinical score were significantly correlated (p<0.001). The semi-automated method described here can provide accurate, reproducible intra-orbital fat measurements with low inter-operator variation and good correlation with clinical data. PMID:24007725

Comerci, M.; Elefante, A.; Strianese, D.; Senese, R.; Bonavolonta, P.; Alfano, B.; Bonavolonta, G.; Brunetti, A.

2013-01-01

21

Interactive Separation of Segmented Bones in CT Volumes Using Graph Cut  

E-print Network

Interactive Separation of Segmented Bones in CT Volumes Using Graph Cut Lu Liu, David Raber, David a fast, interactive method for separating bones that have been collectively segmented from a CT volume. Given user- provided seed points, the method computes the separation as a multi- way cut on a weighted

Ju, Tao

22

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

23

Contour Segment Analysis for Human Silhouette Pre-segmentation  

E-print Network

to the various colors and positions that a person can have, it is a challenging task. The aim is to avoid user, accurate segmentation of these persons is not performed. Many applications however need it. This paper of a known class , and in partic- ular with the one of persons, is a much discussed problem. Due

Paris-Sud XI, Université de

24

Recent advances in segmented gamma scanner analysis  

SciTech Connect

The segmented gamma scanner (SGS) is used in many facilities to assay low-density scrap and waste generated in the facilities. The procedures for using the SGS can cause a negative bias if the sample does not satisfy the assumptions made in the method. Some process samples do not comply with the assumptions. This paper discusses the effect of the presence of lumps on the SGS assay results, describes a method to detect the presence of lumps, and describes an approach to correct for the lumps. Other recent advances in SGS analysis are also discussed.

Sprinkle, J.K. Jr.; Hsue, S.T.

1987-01-01

25

Volume-quantization-based neural network approach to 3D MR angiography image segmentation  

Microsoft Academic Search

Volume visualization of cerebral blood vessels is highly significant for diagnosis of the cerebral diseases. It is because the automated segmentation of the blood vessels from an MR angiography (MRA) image is a knotty problem that there are few works on it. This paper proposes an automated method to segment the blood vessels from 3D time of flight (TOF) MRA

Syoji Kobashi; Naotake Kamiura; Yutaka Hata; Fujio Miyawaki

2001-01-01

26

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

E-print Network

images is an important first step in the analysis of medical images. A lot of research has been performed for the segmentation of brain images. This paper presents a method that can segment multiple slices of an abdominal CT and challenging than brain image segmentation. Test results show that our method can handle large variations

Leow, Wee Kheng

27

Iterative threshold segmentation for PET target volume delineation  

Microsoft Academic Search

The purpose of this work is to create a rigorous method of segmenting PET images using an automated iterative technique. To this end a phantom study employing spherical targets was used to determine local (slice specific) threshold levels which produce correct cross-sections based on the contrast between target and background. Numerous target to background activity concentration ratios were investigated but

Laura Drever; Wilson Roa; Alexander McEwan; Don Robinson

2007-01-01

28

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

29

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

E-print Network

of PET in Intensity- Modulated Radiation Therapy (IMRT) treatment planning renders equally vital1 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

Paris-Sud XI, Université de

30

Learning Taxonomy for Text Segmentation by Formal Concept Analysis  

E-print Network

In this paper the problems of deriving a taxonomy from a text and concept-oriented text segmentation are approached. Formal Concept Analysis (FCA) method is applied to solve both of these linguistic problems. The proposed segmentation method offers a conceptual view for text segmentation, using a context-driven clustering of sentences. The Concept-oriented Clustering Segmentation algorithm (COCS) is based on k-means linear clustering of the sentences. Experimental results obtained using COCS algorithm are presented.

Lupea, Mihaiela; Marian, Zsuzsana

2010-01-01

31

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

32

[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

33

The Tractability of Segmentation and Scene Analysis  

Microsoft Academic Search

One of the fundamental problems in computer vision is the segmentation of an image into semantically meaningful regions, based only on image characteristics. A single segmentation can be determined using a linear number of evaluations of a uniformity predicate. However, minimising the number of regions is shown to be an NP-complete problem. We also show that the variational approach to

Martin C. Cooper

1998-01-01

34

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

35

Automated Retinal Vessel Segmentation Using Multiscale Analysis and Adaptive Thresholding  

Microsoft Academic Search

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

Qin Li; Jane You; Lei Zhang; Prabir Bhattacharya

2006-01-01

36

Topic-based document segmentation with probabilistic latent semantic analysis  

Microsoft Academic Search

This paper presents a new method for topic-based document segmentation, i.e., the identification of boundaries between parts of a document that bear on different topics. The method combines the use of the Probabilistic Latent Semantic Analysis (PLSA) model with the method of selecting segmentation points based on the similarity values between pairs of adjacent blocks. The use of PLSA allows

Thorsten Brants; Francine Chen; Ioannis Tsochantaridis

2002-01-01

37

Segmentation-free Skeletonization of Grayscale Volumes for Shape Understanding  

E-print Network

is demonstrated on both syn- thetic and medical data. Keywords: Grayscale Skeletonization; Structure Tensor; Thin--Curve, surface, solid, and object repre- sentations; I.4.8 [Image Processing and Computer Vision]: Scene Analysis-like shape components is to consider the object's skele- ton [3]. An ideal skeleton for this purpose would

Ju, Tao

38

Active surface segmentation analysis of CCAT  

Microsoft Academic Search

The Cornell Caltech Atacama Sub-millimeter Telescope (CCAT) is proposed to have 25m-diameter primary segmented active surface capable of diffraction-limited operation in the wavelength range between 200 microns to 1mm. The active surface design layout is composed of 162 \\

Germán Cortés-Medellín

2006-01-01

39

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

40

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

41

A local contrast based approach to threshold segmentation for PET target volume delineation  

SciTech Connect

Current radiation therapy techniques, such as intensity modulated radiation therapy and three-dimensional conformal radiotherapy rely on the precise delivery of high doses of radiation to well-defined volumes. CT, the imaging modality that is most commonly used to determine treatment volumes cannot, however, easily distinguish between cancerous and normal tissue. The ability of positron emission tomography (PET) to more readily differentiate between malignant and healthy tissues has generated great interest in using PET images to delineate target volumes for radiation treatment planning. At present the accurate geometric delineation of tumor volumes is a subject open to considerable interpretation. The possibility of using a local contrast based approach to threshold segmentation to accurately delineate PET target cross sections is investigated using well-defined cylindrical and spherical volumes. Contrast levels which yield correct volumetric quantification are found to be a function of the activity concentration ratio between target and background, target size, and slice location. Possibilities for clinical implementation are explored along with the limits posed by this form of segmentation.

Drever, Laura; Robinson, Don M.; McEwan, Alexander; Roa, Wilson [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, T6G 1Z2 (Canada); Department of Oncologic Imaging, Cross Cancer Institute, Edmonton, Alberta, T6G 1Z2 (Canada); Department of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta, T6G 1Z2 (Canada)

2006-06-15

42

Semiautomatic white blood cell segmentation based on multiscale analysis.  

PubMed

This paper approaches novel methods to segment the nucleus and cytoplasm of white blood cells (WBC). This information is the basis to perform higher level tasks such as automatic differential counting, which plays an important role in the diagnosis of different diseases. We explore the image simplification and contour regularization resulting from the application of the Self-Dual Multiscale Morphological Toggle (SMMT), an operator with scale-space properties. To segment the nucleus, the image preprocessing with SMMT has shown to be essential to ensure the accuracy of two well-known image segmentations techniques, namely, watershed transform and Level Set methods. To identify the cytoplasm region, we propose two different schemes, based on granulometric analysis and on morphological transformations. The proposed methods have been successfully applied to a large number of images, showing promising segmentation and classification results for varying cell appearance and image quality, encouraging future works. PMID:22855228

Dorini, L B; Minetto, R; Leite, N J

2013-01-01

43

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

44

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

45

Curvature analysis of periodically segmented waveguides using a modified BPM  

NASA Astrophysics Data System (ADS)

Periodically segmented waveguides (PSWs) are analyzed using a finite-difference beam propagation method (BPM) combined with a coordinate rotation technique. For the analysis of curved PSW, a new technique is proposed to apply the BPM to a waveguide with large propagation angle such as 40° or more, and the curvature effect is taken into consideration in the analysis. The method is applied to treating two kinds of two-dimensional (2-D) PSW, namely straight and bent waveguides with a fixed curvature. For designing 2-D straight PSW, the propagation dependence on the segment period, duty-cycle, etc. is investigated numerically.

Inoue, Masanori; Sakai, Jun-ichi

2004-07-01

46

AUTOMATIC INFERIOR VENA CAVA SEGMENTATION IN CONTRAST-ENHANCED CT VOLUMES  

E-print Network

. In clinical diagnosis and surgery planning, IVC segmentation is essential since it strongly impacts both liver that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart. Before between the IVC and liver parenchyma. Vascular analysis has been a very active field of research in image

Paris-Sud XI, Université de

47

Microscopy image segmentation tool: robust image data analysis.  

PubMed

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

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

2014-03-01

48

Systematic Error in Hippocampal Volume Asymmetry Measurement is Minimal with a Manual Segmentation Protocol  

PubMed Central

Hemispheric asymmetry of hippocampal volume is a common finding that has biological relevance, including associations with dementia and cognitive performance. However, a recent study has reported the possibility of systematic error in measurements of hippocampal asymmetry by magnetic resonance volumetry. We manually traced the volumes of the anterior and posterior hippocampus in 40 healthy people to measure systematic error related to image orientation. We found a bias due to the side of the screen on which the hippocampus was viewed, such that hippocampal volume was larger when traced on the left side of the screen than when traced on the right (p?=?0.05). However, this bias was smaller than the anatomical right?>?left asymmetry of the anterior hippocampus. We found right?>?left asymmetry of hippocampal volume regardless of image presentation (radiological versus neurological). We conclude that manual segmentation protocols can minimize the effect of image orientation in the study of hippocampal volume asymmetry, but our confirmation that such bias exists suggests strategies to avoid it in future studies. PMID:23248580

Rogers, Baxter P.; Sheffield, Julia M.; Luksik, Andrew S.; Heckers, Stephan

2012-01-01

49

Segmentation and analysis of the tissue composition of dermatological ulcers  

Microsoft Academic Search

Ulcered lesions on the legs and feet caused by venous insufficiency and other conditions require long-term clinical treatment and follow-up. To facilitate the analysis of the tissue composition of a lesion, we propose color imaging and image processing methods. Methods considering the bottom tissues are proposed for the segmentation of a given image into regions corresponding to red granulation, yellow

E. A. G. Dorileo; Marco A. C. Frade; Rangaraj M. Rangayyan; Paulo M. Azevedo-Marques

2010-01-01

50

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

51

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

52

Small rural hospitals: an example of market segmentation analysis.  

PubMed

In recent years, market segmentation analysis has shown increased popularity among health care marketers, although marketers tend to focus upon hospitals as sellers. The present analysis suggests that there is merit to viewing hospitals as a market of consumers. Employing a random sample of 741 small rural hospitals, the present investigation sought to determine, through the use of segmentation analysis, the variables associated with hospital success (occupancy). The results of a discriminant analysis yielded a model which classifies hospitals with a high degree of predictive accuracy. Successful hospitals have more beds and employees, and are generally larger and have more resources. However, there was no significant relationship between organizational success and number of services offered by the institution. PMID:10111266

Mainous, A G; Shelby, R L

1991-01-01

53

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

54

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

55

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

56

Survival and Prognostic Analysis of Adjacent Segments after Spinal Fusion  

PubMed Central

Background To examine the survival function and prognostic factors of the adjacent segments based on a second operation after thoracolumbar spinal fusion. Methods This retrospective study reviewed 3,188 patients (3,193 cases) who underwent a thoracolumbar spinal fusion at the author's hospital. Survival analysis was performed on the event of a second operation due to adjacent segment degeneration. The prognostic factors, such as the cause of the disease, surgical procedure, age, gender and number of fusion segments, were examined. Sagittal alignment and the location of the adjacent segment were measured in the second operation cases, and their association with the types of degeneration was investigated. Results One hundred seven patients, 112 cases (3.5%), underwent a second operation due to adjacent segment degeneration. The survival function was 97% and 94% at 5 and 10 years after surgery, respectively, showing a 0.6% linear reduction per year. The significant prognostic factors were old age, degenerative disease, multiple-level fusion and male. Among the second operation cases, the locations of the adjacent segments were the thoracolumbar junctional area and lumbosacral area in 11.6% and 88.4% of cases, respectively. Sagittal alignment was negative or neutral, positive and strongly positive in 47.3%, 38.9%, and 15.7%, respectively. Regarding the type of degeneration, spondylolisthesis or kyphosis, retrolisthesis, and neutral balance in the sagittal view was noted in 13.4%, 36.6%, and 50% of cases, respectively. There was a significant difference according to the location of the adjacent segment (p = 0.000) and sagittal alignment (p = 0.041). Conclusions The survival function of the adjacent segments was 94% at 10 years, which had decreased linearly by 0.6% per a year. The likelihood of a second operation was high in those with old age, degenerative disease, multiple-level fusion and male. There was a tendency for the type of degeneration to be spondylolisthesis or kyphosis in cases of the thoracolumbar junctional area and strongly positive sagittal alignment, but retrolisthesis in cases of the lumbosacral area and neutral or positive sagittal alignment. PMID:20808584

Ahn, Dong Ki; Choi, Dae Jung; Kim, Kwan Soo; Yang, Seung Jin

2010-01-01

57

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

58

Image segmentation and registration for the analysis of joint motion from 3D MRI  

NASA Astrophysics Data System (ADS)

We report an image segmentation and registration method for studying joint morphology and kinematics from in vivo MRI scans and its application to the analysis of ankle joint motion. Using an MR-compatible loading device, a foot was scanned in a single neutral and seven dynamic positions including maximal flexion, rotation and inversion/eversion. A segmentation method combining graph cuts and level sets was developed which allows a user to interactively delineate 14 bones in the neutral position volume in less than 30 minutes total, including less than 10 minutes of user interaction. In the subsequent registration step, a separate rigid body transformation for each bone is obtained by registering the neutral position dataset to each of the dynamic ones, which produces an accurate description of the motion between them. We have processed six datasets, including 3 normal and 3 pathological feet. For validation our results were compared with those obtained from 3DViewnix, a semi-automatic segmentation program, and achieved good agreement in volume overlap ratios (mean: 91.57%, standard deviation: 3.58%) for all bones. Our tool requires only 1/50 and 1/150 of the user interaction time required by 3DViewnix and NIH Image Plus, respectively, an improvement that has the potential to make joint motion analysis from MRI practical in research and clinical applications.

Hu, Yangqiu; Haynor, David R.; Fassbind, Michael; Rohr, Eric; Ledoux, William

2006-03-01

59

Forest Volume and Biomass Estimation Using Small-Footprint Lidar-Distributional Parameters on a Per-Segment Basis  

Microsoft Academic Search

This study assessed a lidar-based, object-oriented (segmentation) approach to forest volume and aboveground biomass modeling. The study area in the Piedmont physiographic region of Virginia is composed of temperate coniferous, deciduous, and mixed stands. Segmentation objects, hierarchical in terms of area and ranging from 0.035 to 5.632 ha\\/object, were created using a lidar-derived canopy height model. Horizontal point (basal area)

Jan A. N. van Aardt; Randolph H. Wynne; Richard G. Oderwald

60

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

NASA Technical Reports Server (NTRS)

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

1972-01-01

61

Atlas-based automatic segmentation of head and neck organs at risk and nodal target volumes: a clinical validation  

PubMed Central

Background Intensity modulated radiotherapy for head and neck cancer necessitates accurate definition of organs at risk (OAR) and clinical target volumes (CTV). This crucial step is time consuming and prone to inter- and intra-observer variations. Automatic segmentation by atlas deformable registration may help to reduce time and variations. We aim to test a new commercial atlas algorithm for automatic segmentation of OAR and CTV in both ideal and clinical conditions. Methods The updated Brainlab automatic head and neck atlas segmentation was tested on 20 patients: 10 cN0-stages (ideal population) and 10 unselected N-stages (clinical population). Following manual delineation of OAR and CTV, automatic segmentation of the same set of structures was performed and afterwards manually corrected. Dice Similarity Coefficient (DSC), Average Surface Distance (ASD) and Maximal Surface Distance (MSD) were calculated for “manual to automatic” and “manual to corrected” volumes comparisons. Results In both groups, automatic segmentation saved about 40% of the corresponding manual segmentation time. This effect was more pronounced for OAR than for CTV. The edition of the automatically obtained contours significantly improved DSC, ASD and MSD. Large distortions of normal anatomy or lack of iodine contrast were the limiting factors. Conclusions The updated Brainlab atlas-based automatic segmentation tool for head and neck Cancer patients is timesaving but still necessitates review and corrections by an expert. PMID:23803232

2013-01-01

62

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

PubMed Central

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

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

2010-01-01

63

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

PubMed

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

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

2014-12-01

64

Comparing manual and automatic segmentation of hippocampal volumes: reliability and validity issues in younger and older brains.  

PubMed

We compared hippocampal volume measures obtained by manual tracing to automatic segmentation with FreeSurfer in 44 younger (20-30 years) and 47 older (60-70 years) adults, each measured with magnetic resonance imaging (MRI) over three successive time points, separated by four months. Retest correlations over time were very high for both manual and FreeSurfer segmentations. With FreeSurfer, correlations over time were significantly lower in the older than in the younger age group, which was not the case with manual segmentation. Pearson correlations between manual and FreeSurfer estimates were sufficiently high, numerically even higher in the younger group, whereas intra-class correlation coefficient (ICC) estimates were lower in the younger than in the older group. FreeSurfer yielded higher volume estimates than manual segmentation, particularly in the younger age group. Importantly, FreeSurfer consistently overestimated hippocampal volumes independently of manually assessed volume in the younger age group, but overestimated larger volumes in the older age group to a less extent, introducing a systematic age bias in the data. Age differences in hippocampal volumes were significant with FreeSurfer, but not with manual tracing. Manual tracing resulted in a significant difference between left and right hippocampus (right > left), whereas this asymmetry effect was considerably smaller with FreeSurfer estimates. We conclude that FreeSurfer constitutes a feasible method to assess differences in hippocampal volume in young adults. FreeSurfer estimates in older age groups should, however, be interpreted with care until the automatic segmentation pipeline has been further optimized to increase validity and reliability in this age group. PMID:24532539

Wenger, Elisabeth; Mårtensson, Johan; Noack, Hannes; Bodammer, Nils Christian; Kühn, Simone; Schaefer, Sabine; Heinze, Hans-Jochen; Düzel, Emrah; Bäckman, Lars; Lindenberger, Ulman; Lövdén, Martin

2014-08-01

65

Education, Work and Employment--Volume II. Segmented Labour Markets, Workplace Democracy and Educational Planning, Education and Self-Employment.  

ERIC Educational Resources Information Center

This volume contains three studies covering separate yet complementary aspects of the problem of the relationships between the educational system and the production system as manpower user. The first monograph on the theories of the markets seeks to answer two questions: what can be learned from the work done on the segmentation of the labor…

Carnoy, Martin; And Others

66

Segmentation of multiple sclerosis lesions in MRI: an image analysis approach  

NASA Astrophysics Data System (ADS)

This paper describes an intensity-based method for the segmentation of multiple sclerosis lesions in dual-echo PD and T2-weighted magnetic resonance brain images. The method consists of two stages: feature extraction and image analysis. For feature extraction, we use a ratio filter transformation on the proton density (PD) and spin-spin (T2) data sequences to extract the white matter, cerebrospinal fluid and the lesion features. The one and two dimensional histograms of the features are then analyzed to obtain different parameters, which provide the basis for subsequent image analysis operations to detect the multiple sclerosis lesions. In the image analysis stage, the PD images of the volume are first pre-processed to enhance the lesion tissue areas. White matter and cerebrospinal fluid masks are then generated and applied on the enhanced volume to remove non- lesion areas. Segmentation of lesions is performed in two steps: conspicuous lesions are extracted in the first step, followed by the extraction of the subtle lesions.

Krishnan, Kalpagam; Atkins, M. Stella

1998-06-01

67

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

68

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

69

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

70

Nonparametric statistical methods for image segmentation and shape analysis  

E-print Network

Image segmentation, the process of decomposing an image into meaningful regions, is a fundamental problem in image processing and computer vision. Recently, image segmentation techniques based on active contour models with ...

Kim, Junmo, 1976-

2005-01-01

71

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

E-print Network

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

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

2004-04-07

72

A Cautionary Analysis of STAPLE Using Direct Inference of Segmentation Truth  

E-print Network

by different human expert raters, to fusing registration-based automatic segmentations in multi-atlas labelA Cautionary Analysis of STAPLE Using Direct Inference of Segmentation Truth Koen Van Leemput1 the average of the input segmentations. We further show that when the number of raters is small, the STAPLE re

73

An Integrated Segmentation and Classification Approach Applied to Multiple Sclerosis Analysis  

E-print Network

utility in detecting Multiple Sclerosis lesions in 3D multi-channel MRI data. Our method uses segmentation all components, EM, template driven segmentation(TDS) employing a deformable digital anatomical atlas1 An Integrated Segmentation and Classification Approach Applied to Multiple Sclerosis Analysis

74

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

Microsoft Academic Search

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

Marianne Fenech; Michel Y. Jaffrin

2004-01-01

75

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

E-print Network

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

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

2011-01-01

76

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

77

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

78

Fractal Segmentation and Clustering Analysis for Seismic Time Slices  

NASA Astrophysics Data System (ADS)

Fractal analysis has become part of the standard approach for quantifying texture on gray-tone or colored images. In this research we introduce a multi-stage fractal procedure to segment, classify and measure the clustering patterns on seismic time slices from a 3-D seismic survey. Five fractal classifiers (c1)-(c5) were designed to yield standardized, unbiased and precise measures of the clustering of seismic signals. The classifiers were tested on seismic time slices from the AKAL field, Cantarell Oil Complex, Mexico. The generalized lacunarity (c1), fractal signature (c2), heterogeneity (c3), rugosity of boundaries (c4) and continuity resp. tortuosity (c5) of the clusters are shown to be efficient measures of the time-space variability of seismic signals. The Local Fractal Analysis (LFA) of time slices has proved to be a powerful edge detection filter to detect and enhance linear features, like faults or buried meandering rivers. The local fractal dimensions of the time slices were also compared with the self-affinity dimensions of the corresponding parts of porosity-logs. It is speculated that the spectral dimension of the negative-amplitude parts of the time-slice yields a measure of connectivity between the formation's high-porosity zones, and correlates with overall permeability.

Ronquillo, G.; Oleschko, K.; Korvin, G.; Arizabalo, R. D.

2002-05-01

79

What is the best segment duration for music mood analysis ?  

Microsoft Academic Search

Music mood present the inherent emotional state of music on certain duration of music segment. However, the mood may vary in the music pieces. Thus it is important to investigate the duration of music segments which can best present the stable mood states in music. Four versions of music datasets with duration of clips from 4 seconds to 32 seconds

Zhongzhe Xiao; Emmanuel Dellandrea; Weibei Dou; Liming Chen

2008-01-01

80

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

81

Recurrence interval analysis of trading volumes  

NASA Astrophysics Data System (ADS)

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

Ren, Fei; Zhou, Wei-Xing

2010-06-01

82

Multiresolution mesh segmentation based on surface roughness and wavelet analysis  

NASA Astrophysics Data System (ADS)

During the last decades, the three-dimensional objects have begun to compete with traditional multimedia (images, sounds and videos) and have been used by more and more applications. The common model used to represent them is a surfacic mesh due to its intrinsic simplicity and efficacity. In this paper, we present a new algorithm for the segmentation of semi-regular triangle meshes, via multiresolution analysis. Our method uses several measures which reflect the roughness of the surface for all meshes resulting from the decomposition of the initial model into different fine-to-coarse multiresolution meshes. The geometric data decomposition is based on the lifting scheme. Using that formulation, we have compared various interpolant prediction operators, associated or not with an update step. For each resolution level, the resulting approximation mesh is then partitioned into classes having almost constant roughness thanks to a clustering algorithm. Resulting classes gather regions having the same visual appearance in term of roughness. The last step consists in decomposing the mesh into connex groups of triangles using region growing ang merging algorithms. These connex surface patches are of particular interest for adaptive mesh compression, visualisation, indexation or watermarking.

Roudet, Céline; Dupont, Florent; Baskurt, Atilla

2007-01-01

83

Fusing Markov random fields with anatomical knowledge and shape-based analysis to segment multiple sclerosis white matter lesions in magnetic resonance images of the brain  

NASA Astrophysics Data System (ADS)

This paper proposes an image analysis system to segment multiple sclerosis lesions of magnetic resonance (MR) brain volumes consisting of 3 mm thick slices using three channels (images showing T1-, T2- and PD -weighted contrast). The method uses the statistical model of Markov Random Fields (MRF) both at low and high levels. The neighborhood system used in this MRF is defined in three types: (1) Voxel to voxel: a low-level heterogeneous neighborhood system is used to restore noisy images. (2) Voxel to segment: a fuzzy atlas, which indicates the probability distribution of each tissue type in the brain, is registered elastically with the MRF. It is used by the MRF as a-priori knowledge to correct miss-classified voxels. (3) Segment to segment: Remaining lesion candidates are processed by a feature based classifier that looks at unary and neighborhood information to eliminate more false positives. An expert's manual segmentation was compared with the algorithm.

AlZubi, Stephan; Toennies, Klaus D.; Bodammer, N.; Hinrichs, Herman

2002-05-01

84

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

85

Automated detection, 3D segmentation and analysis of high resolution spine MR images using statistical shape models  

NASA Astrophysics Data System (ADS)

Recent advances in high resolution magnetic resonance (MR) imaging of the spine provide a basis for the automated assessment of intervertebral disc (IVD) and vertebral body (VB) anatomy. High resolution three-dimensional (3D) morphological information contained in these images may be useful for early detection and monitoring of common spine disorders, such as disc degeneration. This work proposes an automated approach to extract the 3D segmentations of lumbar and thoracic IVDs and VBs from MR images using statistical shape analysis and registration of grey level intensity profiles. The algorithm was validated on a dataset of volumetric scans of the thoracolumbar spine of asymptomatic volunteers obtained on a 3T scanner using the relatively new 3D T2-weighted SPACE pulse sequence. Manual segmentations and expert radiological findings of early signs of disc degeneration were used in the validation. There was good agreement between manual and automated segmentation of the IVD and VB volumes with the mean Dice scores of 0.89 ± 0.04 and 0.91 ± 0.02 and mean absolute surface distances of 0.55 ± 0.18 mm and 0.67 ± 0.17 mm respectively. The method compares favourably to existing 3D MR segmentation techniques for VBs. This is the first time IVDs have been automatically segmented from 3D volumetric scans and shape parameters obtained were used in preliminary analyses to accurately classify (100% sensitivity, 98.3% specificity) disc abnormalities associated with early degenerative changes.

Neubert, A.; Fripp, J.; Engstrom, C.; Schwarz, R.; Lauer, L.; Salvado, O.; Crozier, S.

2012-12-01

86

Characterization of Chelonus inanitus polydnavirus segments: sequences and analysis, excision site and demonstration of clustering  

Microsoft Academic Search

Polydnaviruses (genera Ichnovirus and Bracovirus) have a segmented genome of circular double- stranded DNA molecules, replicate in the ovary of parasitic wasps and are essential for successful parasitism of the host. Here we show the first detailed analysis of various segments of a bracovirus, the Chelonus inanitus virus (CiV). Four segments were sequenced and two of them, CiV12 and CiV14,

Stefan Wyder; Adrian Tschannen; Anita Hochuli; Andreas Gruber; Verena Saladin; Sonja Zumbach; Beatrice Lanzrein

2002-01-01

87

Molecular cytogenetic analysis of supernumerary heterochromatic segments in Rumex acetosa.  

PubMed

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

Shibata, F; Hizume, M; Kuroki, Y

2000-04-01

88

Fluorescence Correlation Spectroscopy analysis of segmental dynamics in Actin filaments  

E-print Network

We adapt Fluorescence Correlation spectroscopy (FCS) formalism to the studies of the dynamics of semi-flexible polymers and derive expressions relating FCS correlation function to the longitudinal and transverse mean square displacements of polymer segments. We use the derived expressions to measure the dynamics of actin filaments in two experimental situations: filaments labeled at distinct positions and homogeneously labeled filaments. Both approaches give consistent results and allow to measure the temporal dependence of the segmental mean-square displacement (MSD) over almost five decades in time, from ~0.04ms to 2s. These noninvasive measurements allow for a detailed quantitative comparison of the experimental data to the current theories of semi-flexible polymer dynamics. Good quantitative agreement is found between the experimental results and theories explicitly accounting for the hydrodynamic interactions between polymer segments.

Anne Bernheim-Groswasser; Roman Shusterman; Oleg Krichevsky

2006-03-12

89

REACH. Teacher's Guide, Volume III. Task Analysis.  

ERIC Educational Resources Information Center

Designed for use with individualized instructional units (CE 026 345-347, CE 026 349-351) in the electromechanical cluster, this third volume of the postsecondary teacher's guide presents the task analysis which was used in the development of the REACH (Refrigeration, Electro-Mechanical, Air Conditioning, Heating) curriculum. The major blocks of…

Morris, James Lee; And Others

90

Performance analysis of the segment alignment control system for the ten-meter telescope  

Microsoft Academic Search

A dynamic analysis of the control system used to align the 36 hexagonal segments of the primary mirror of the Keck Observatory ten-meter telescope has been performed, evaluating the effect of the interaction between the segment alignment control system, the wind disturbances, and the telescope structural dynamics on the telescope's optical performance. Actual wind velocities measured at three observatory sites

J.-N. Aubrun; K. R. Lorell; T. W. Havas; W. C. Henninger

1988-01-01

91

Segmenting casino gamblers by motivation: A cluster analysis of Korean gamblers  

Microsoft Academic Search

While past research has explored why people become problem or pathological gamblers, the motivations of the broader gambling population have been largely neglected. This study examines casino gambling motivations for a sample of Korean gamblers. Specifically, this study attempts to segment the casino gambling market using a cluster analysis, and to explore differences between segments with respect to socio-demographic and

Choong-Ki Lee; Yong-Ki Lee; Bo Jason Bernhard; Yoo-Shik Yoon

2006-01-01

92

A New Approach to Automated Retinal Vessel Segmentation Using Multiscale Analysis  

Microsoft Academic Search

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

Qin Li; Lei Zhang; David Zhang; Prabir Bhattacharya

2006-01-01

93

A New Approach to Automated Retinal Vessel Segmentation Using Multiscale Analysis  

Microsoft Academic Search

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

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

2009-01-01

94

A new method to segment playfield and its applications in match analysis in sports video  

Microsoft Academic Search

With the growing popularity of digitized sports video, automatic analysis of them need be processed to facilitate semantic summarization and retrieval. Playfield plays the fundamental role in automatically analyzing many sports programs. Many semantic clues could be inferred from the results of playfield segmentation. In this paper, a novel playfield segmentation method based on Gaussian mixture models (GMMs) is proposed.

Shuqiang Jiang; Qixiang Ye; Wen Gao; Tiejun Huang

2004-01-01

95

Preliminary analysis of the Knipovich Ridge segmentation: inuence of focused magmatism and ridge obliquity on  

E-print Network

reserved. Keywords: mid-ocean ridges; segmentation; sea-£oor spreading; gravity anomalies; sonar methods question facing modern investigation of mid-ocean ridge tectonics and geophysics [1]. Although spreadingPreliminary analysis of the Knipovich Ridge segmentation: in£uence of focused magmatism and ridge

Okino, Kyoko

96

Wavefront Control Algorithms and Analysis for a Dense Adaptive Optics System with Segmented Primary Mirror  

Microsoft Academic Search

This paper presents the development and analysis of a wavcfront control strategy for a dense adaptive optics systcm with segmented primary mirror. Systems of this type represent a substantial departure from most conventional adaptive optics systems in that the deformable clcmcnt is the segmented primary mirror and the fccdhack signal includes both the local wavefront tilt and the relative edge

Mark Milman; Amir Fijany

97

Analysis of the Yokeless And Segmented Armature Machine  

Microsoft Academic Search

This paper presents a new type of axial flux motor, the yokeless and segmented armature (YASA) topology. The YASA motor has no stator yoke, a high fill factor and short end windings which all increase torque density and efficiency of the machine. Thus, the topology is highly suited for high performance applications. The LIFEcar project is aimed at producing the

T. J. Woolmer; M. D. McCulloch

2007-01-01

98

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.

99

Analysis of piezoelectric bimorphs and plates with segmented actuators  

Microsoft Academic Search

Elastic plates with distributed or segmented piezoelectric layers have been analyzed using the classical laminated plate theory, the first-order shear deformation theory, and the results are compared with an analytical solution. The plate theories and the analytical solution take into account both the direct and the converse piezoelectric effects, and assume generalized plane strain deformations. The transverse displacements from both

Senthil S. Vel; R. C. Batra

2001-01-01

100

Analysis of segmental kinetic energy in cricket bowling  

Microsoft Academic Search

Fast bowling in cricket is an athletic motion requiring the coordination of multiple body segments in order to release a ball at high speed. The application of the kinetic link principle to bowling proposes that the optimal coordination of movement actuation follows a proximal to distal sequence, allowing the systematic and progressive transfer of angular momentum from the larger, heavier

René E. D. Ferdinands

2011-01-01

101

Comparative analysis of different focusators focusing into a segment  

Microsoft Academic Search

Computer generated diffractive optical elements, known as ‘focusators’, provide very complicated focal intensity distributions. The manufacture of such elements is very expensive and must be preceded by computer simulation of their performance. A computational experiment, with laser beam focusators focusing into a segment, is described in this paper. Estimations of power efficiency and focal line quality for various focusator phase

L. L. Doskolovich; N. L. Kazanskiy; V. A. Soifer

1995-01-01

102

Strategic and operational market segmentation: a managerial analysis  

Microsoft Academic Search

One of the most widely used and familiar theories in marketing is market segmentation — the familiar protocols for the division of markets in a variety of ways into homogeneous groups of buyers, to form differentiated targets for marketing strategies and programmes. However, the view developed in this paper is that the conventional explication of this conceptual framework ignores some

Nigel F. Piercy; Neil A. Morgan

1993-01-01

103

Semantic-event based analysis and segmentation of wedding ceremonyvideos  

Microsoft Academic Search

Wedding is one of the most important ceremonies in our lives. It symbolizes the birth and creation of a new fam- ily. In this paper, we present a system for automatically segmenting a wedding ceremony video into a sequence of recognized wedding events, e.g., the couple's wedding kiss. Our goal is to develop an automatic tool for users to effi-

Wen-Huang Cheng; Yung-Yu Chuang; Bing-Yu Chen; Ja-Ling Wu; Yin-Tzu Lin

2007-01-01

104

Document image segmentation and quality improvement by moiré pattern analysis  

Microsoft Academic Search

Moiré patterns are distortions on the results of scanning printed documents. However, the patterns can be utilized in document image segmentation and quality improvement. The moiré phenomenon comes from sampling periodical structures in images, such as halftone screens, color components, and text galleys which often appear in printed magazines and newspapers. The generated moiré patterns appear in the scanning result

James Ching-Yu Yang; Wen-Hsiang Tsai

2000-01-01

105

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

106

Multi-rigid image segmentation and registration for the analysis of joint motion from three-dimensional magnetic resonance imaging.  

PubMed

We report an image segmentation and registration method for studying joint morphology and kinematics from in vivo magnetic resonance imaging (MRI) scans and its application to the analysis of foot and ankle joint motion. Using an MRI-compatible positioning device, a foot was scanned in a single neutral and seven other positions ranging from maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation. A segmentation method combining graph cuts and level set was developed. In the subsequent registration step, a separate rigid body transformation for each bone was obtained by registering the neutral position dataset to each of the other ones, which produced an accurate description of the motion between them. The segmentation algorithm allowed a user to interactively delineate 14 foot bones in the neutral position volume in less than 30 min total (user and computer processing unit [CPU]) time. Registration to the seven other positions took approximately 10 additional minutes of user time and 5.25 h of CPU time. For validation, our results were compared with those obtained from 3DViewnix, a semiautomatic segmentation program. We achieved excellent agreement, with volume overlap ratios greater than 88% for all bones excluding the intermediate cuneiform and the lesser metatarsals. For the registration of the neutral scan to the seven other positions, the average overlap ratio is 94.25%, while the minimum overlap ratio is 89.49% for the tibia between the neutral position and position 1, which might be due to different fields of view (FOV). To process a single foot in eight positions, our tool requires only minimal user interaction time (less than 30 min total), a level of improvement that has the potential to make joint motion analysis from MRI practical in research and clinical applications. PMID:22070330

Hu, Yangqiu; Ledoux, William R; Fassbind, Michael; Rohr, Eric S; Sangeorzan, Bruce J; Haynor, David

2011-10-01

107

Sport divers and underwater parks: a market segmentation analysis  

E-print Network

and the following variables: (i) diving experience; (ii) type of activities participated in ; (iii) expressed level of satisfaction with dive sites; (iv) the type of developed site selected; (v) frequency of participation; (vi) distance travelled to dive sites...; (vii) different types, sizes, and compositions of diving social groups; (viii) resource setting preferences, 'and (ix) planning and management action preferences Understanding these different market segments of sport divers who use underwater parks...

Matheusik, Mick Eric

2012-06-07

108

An Experimental Analysis of Phoneme Blending and Segmenting Skills  

Microsoft Academic Search

In this 2-experiment study, experimental analyses of phoneme blending and segmenting skills were conducted with four-first\\u000a grade students. Intraindividual analyses were conducted to identify the effects of classroom-based instruction on blending\\u000a phonemes in Experiment 1. In Experiment 2, the effects of an individualized intervention for the student who failed to improve\\u000a in the first experiment were examined. Stimulus materials were

Edward J. Daly; Sarah Johnson; Courtney LeClair

2009-01-01

109

Fire flame detection using color segmentation and space-time analysis  

Microsoft Academic Search

This paper presents a fire flame detection using CCTV cameras based on image processing. The scheme relies on color segmentation and space-time analysis. The segmentation is performed to extract fire-like-color regions in an image. Many methods are benchmarked against each other to find the best for practical CCTV camera. After that, the space-time analysis is used to recognized fire behavior.

Miti Ruchanurucks; Praphin Saengngoen; Theeraphat Sajjawiso

2011-01-01

110

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

E-print Network

diagnosis and monitoring response to therapy, applications such as the use of PET in Intensity 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

111

Diffractive imaging analysis of large-aperture segmented telescope based on partial Fourier transform  

NASA Astrophysics Data System (ADS)

Large-aperture segmented primary mirror will be widely used in next-generation space-based and ground-based telescopes. The effects of intersegment gaps, obstructions, position and figure errors of segments, which are all involved in the pupil plane, on the image quality metric should be analyzed using diffractive imaging theory. Traditional Fast Fourier Transform (FFT) method is very time-consuming and costs a lot of memory especially in dealing with large pupil-sampling matrix. A Partial Fourier Transform (PFT) method is first proposed to substantially speed up the computation and reduce memory usage for diffractive imaging analysis. Diffraction effects of a 6-meter segmented mirror including 18 hexagonal segments are simulated and analyzed using PFT method. The influence of intersegment gaps and position errors of segments on Strehl ratio is quantitatively analyzed by computing the Point Spread Function (PSF). By comparing simulation results with theoretical results, the correctness and feasibility of PFT method is confirmed.

Dong, Bing; Qin, Shun; Hu, Xinqi

2013-09-01

112

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

113

SEMANTIC SEGMENTATION OF RADIO PROGRAMS USING SOCIAL NETWORK ANALYSIS AND DURATION DISTRIBUTION MODELING  

E-print Network

SEMANTIC SEGMENTATION OF RADIO PROGRAMS USING SOCIAL NETWORK ANALYSIS AND DURATION DISTRIBUTION: the first is based on Social Network Analysis, the second is based on Pois- son Stochastic Processes, the results are promising and encourage to continue with the application of Social Network Analysis

114

Broadcast News Story Segmentation Using Social Network Analysis and Hidden Markov Models  

E-print Network

Broadcast News Story Segmentation Using Social Network Analysis and Hidden Markov Models Alessandro to stories. The approach is based on Social Network Analysis (for the representation of social re]: General Terms: Experimentation. Keywords: Social Network Analysis, Hidden Markov Mod- els, Story

115

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

116

Vessel segmentation analysis of ischemic stroke images acquired with photoacoustic microscopy  

NASA Astrophysics Data System (ADS)

We have applied optical-resolution photoacoustic microscopy (OR-PAM) for longitudinal monitoring of cerebral metabolism through the intact skull of mice before, during, and up to 72 hours after a 1-hour transient middle cerebral artery occlusion (tMCAO). The high spatial resolution of OR-PAM enabled us to develop vessel segmentation techniques for segment-wise analysis of cerebrovascular responses.

Soetikno, Brian; Hu, Song; Gonzales, Ernie; Zhong, Qiaonan; Maslov, Konstantin; Lee, Jin-Moo; Wang, Lihong V.

2012-02-01

117

Health lifestyles: audience segmentation analysis for public health interventions.  

PubMed

This article is concerned with the application of market segmentation techniques in order to improve the planning and implementation of public health education programs. Seven distinctive patterns of health attitudes, social influences, and behaviors are identified using cluster analytic techniques in a sample drawn from four central California cities, and are subjected to construct and predictive validation: The lifestyle clusters predict behaviors including seatbelt use, vitamin C use, and attention to health information. The clusters also predict self-reported improvements in health behavior as measured in a two-year follow-up survey, e.g., eating less salt and losing weight, and self-reported new moderate and new vigorous exercise. Implications of these lifestyle clusters for public health education and intervention planning, and the larger potential of lifestyle clustering techniques in public health efforts, are discussed. PMID:2055779

Slater, M D; Flora, J A

1991-01-01

118

Segmental Analysis of Carotid Arterial Strain Using Speckle-Tracking  

PubMed Central

Background Increased arterial stiffness has been shown to be associated with aging and cardiovascular risk factors. Speckle-tracking algorithms are being used to measure myocardial strain. We evaluated if speckle-tracking could be used to measure carotid arterial wall strain (CAS) reproducibly in healthy volunteers and then examined if CAS was lesser in individuals with diabetes. Methods Bilateral electrocardiography-gated ultrasound scans of the distal common carotid arteries [D-CCA] (3 cardiac cycles, 14 MHz linear probe, mean 78.7 [Standard deviation (SD) 8.9]) frames per second were performed twice (2–4 days apart) on 10 healthy volunteers to test repeatability. Differences in CAS between healthy (n=20) and diabetic subjects (n=21) were examined. Peak CAS was measured in each of 6 equal segments and averages of all segments (i.e., global average), of the 3 nearest the probe, and of the 3 farthest from the probe (i.e., far wall average) were obtained. Results Global CAS (intraclass correlation coefficient [ICC]=0.40) and far wall average (ICC=0.63) had the greatest test-retest reliability. The global and far wall averaged CAS were lower in diabetics (4.29% [Standard Error (SE) 0.27%]; 4.30% [SE 0.44%], respectively) than in controls (5.48% [SE 0.29%], p=0.001; 5.58% [SE 0.44%], p=0.003, respectively). This difference persisted after adjustment for age, gender, race, and hemodynamic parameters. Conclusions Speckle-tracking for measuring carotid arterial wall strain is feasible and modestly reliable. Diabetic subjects had a lower carotid arterial wall strain obtained with speckle-tracking when compared with healthy controls. PMID:21907541

Yang, Eric Y.; Dokainish, Hisham; Virani, Salim S.; Misra, Arunima; Pritchett, Allison M.; Lakkis, Nasser; Brunner, Gerd; Bobek, Jaromir; McCulloch, Marti L.; Hartley, Craig J.; Ballantyne, Christie M.; Nagueh, Sherif F.; Nambi, Vijay

2011-01-01

119

Posterior segment laser scanning tomography: contour-line modulation in optic disk analysis  

NASA Astrophysics Data System (ADS)

Laser scanning tomography is a technique for obtaining three-dimensional morphometric measurements in vivo. Beside " volumetric" parameters for optic disk analysis eg excavation volume maximal excavation depth or third moment of frequency distribution of excavation depth readings the evaluation of a new parameter the contour-line modulation is of special interest. The contour-line defines the disk border. In laser scanning tomography each pixel of the contourline is defined three-dimensionally. The contour-line modulation is the difference in height readings between the mean height position of the contour-line in the segment under investigation and the mean height position of the contour-line of an optic disk. We analysed a series of 27 control group eyes of 27 patients (C no defects in computerized static 30 degree visual field test octopus program 32 or 38) and 38 glaucoma eyes of 38 patients (G at least three points with a relative scotoma of -1 0dB loss or greater). Within the temporal 1 800 of the optic nerve head the contour-line modulation values were +79 m for the temporal superior octant (G) and +40 m for the temporal inferior octant (G) compared to the temporal quadrant and +1 71 pm for the temporal superior octant (C) and +1 34 tm for the temporal inferior octant (C) respectively . These data suggest that contour-line modulation values may be a quantitative structural parameter for nerve fiber bundle defects. Further studies

Burk, Reinhard O. W.; Rohrschneider, Klaus; Voelcker, Hans E.

1990-11-01

120

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

121

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

122

Detection of repeated arsenical poisoning by neutron activation analysis of foot nail segments  

Microsoft Academic Search

In one case of repeated ingestions of arsenic over a period of one year, the value of sectional toe nail analysis was investigated. The arsenic determinations were performed by instrumental neutron activation analysis. After subdividing the nail transversely into segments of 0.5 mm length, several maxima and minima of arsenic concentrations were found. Taking the nail growth into consideration, these

G. Henke; A. Nucci; L. S. Queiroz

1982-01-01

123

Discrete Laplace-Beltrami Operators for Shape Analysis and Segmentation  

Microsoft Academic Search

Shape analysis plays a pivotal role in a large number of applications, ranging from traditional geometry processing to more recent 3D content management. In this scenario, spectral methods are extremely promising as they provide a natural library of tools for shape analysis, intrinsically defined by the shape itself. I n particular, the eigenfunctions of the Laplace-Beltrami o perator yield a

Martin Reuter; Silvia Biasotti; Daniela Giorgi; Giuseppe Patane; Michela Spagnuolo

124

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

NASA Technical Reports Server (NTRS)

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

Daly, R.

1983-01-01

125

Fire flame detection using color segmentation and space-time analysis  

NASA Astrophysics Data System (ADS)

This paper presents a fire flame detection using CCTV cameras based on image processing. The scheme relies on color segmentation and space-time analysis. The segmentation is performed to extract fire-like-color regions in an image. Many methods are benchmarked against each other to find the best for practical CCTV camera. After that, the space-time analysis is used to recognized fire behavior. A space-time window is generated from contour of the threshold image. Feature extraction is done in Fourier domain of the window. Neural network is used for behavior recognition. The system will be shown to be practical and robust.

Ruchanurucks, Miti; Saengngoen, Praphin; Sajjawiso, Theeraphat

2011-10-01

126

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

127

Customer decision making in fashion retailing: a segmentation analysis  

Microsoft Academic Search

Research into store image, market positioning and store choice has mainly been carried out in supermarkets or department stores and only a limited amount in speciality retailing. This study uses conjoint analysis to examine the way consumers choose where to purchase menswear fashion clothing, based on their perception and trade-off of four attributes - price, quality, selection and staff -

Grete Birtwistle; Ian Clarke; Paul Freathy

1998-01-01

128

Genetic and expression analysis of enabled in Drosophila leg segmentation  

E-print Network

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

Ramel, Marie-Christine

2012-06-07

129

24 Hour ST Segment Analysis in Transient Left Ventricular Apical Ballooning  

PubMed Central

Objective The etiologic basis of transient left ventricular apical ballooning, a novel cardiac syndrome, is not clear. Among the proposed pathomechanisms is coronary vasospasm. Long-term ST segment analysis may detect vasospastic episodes but has not been reported. Methods 30 consecutive patients with transient left ventricular apical ballooning, left ventricular dysfunction and normal or near-normal coronary arteries were investigated. A 24-hour Holter ECG was obtained after emergency admission. ST segment analysis was performed automatically in 2 leads and confirmed by visual inspection. Criteria for an ischemic event were: 1. ST elevation or 2. horizontal or down-sloping ST segments ?1 min duration and ?100 µV J+80 point deviation corrected for baseline ST-deviation. Results Patients presented with ST segment elevation (n?=?19) and/or T wave inversion (n?=?20) on admission ECG. Ejection fraction was 50±12%. No transient ST elevations were observed during Holter ECG analysis. In 3 patients, 8 transient episodes of ST depression were recorded. Durations of episodes varied between 75s and 790s (mean 229s). Maximal ST deviation averaged ?191±71 µV. Ischemic burden was ?1 to ?22 mVs (mean ?8 mVs). 27 patients showed no ischemic events. Conclusions ST segment analysis of 24 h Holter recordings revealed minor ischemic events in only 10% of patients with transient left ventricular apical ballooning. Overall, ST segment changes were not indicative of recurrent coronary spasm playing a major role in the genesis of transient left ventricular apical ballooning. PMID:23505493

Bode, Frank; Burgdorf, Christof; Schunkert, Heribert; Kurowski, Volkhard

2013-01-01

130

Robust Detection and Identification of Sparse Segments in Ultra-High Dimensional Data Analysis  

PubMed Central

Summary Copy number variants (CNVs) are alternations of DNA of a genome that results in the cell having a less or more than two copies of segments of the DNA. CNVs correspond to relatively large regions of the genome, ranging from about one kilobase to several megabases, that are deleted or duplicated. Motivated by CNV analysis based on next generation sequencing data, we consider the problem of detecting and identifying sparse short segments hidden in a long linear sequence of data with an unspecified noise distribution. We propose a computationally efficient method that provides a robust and near-optimal solution for segment identification over a wide range of noise distributions. We theoretically quantify the conditions for detecting the segment signals and show that the method near-optimally estimates the signal segments whenever it is possible to detect their existence. Simulation studies are carried out to demonstrate the efficiency of the method under different noise distributions. We present results from a CNV analysis of a HapMap Yoruban sample to further illustrate the theory and the methods. PMID:23393425

Cai, T. Tony; Jeng, X. Jessie; Li, Hongzhe

2012-01-01

131

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

132

Analysis of Hantavirus Genetic Diversity in Argentina: S Segment-Derived Phylogeny  

Microsoft Academic Search

Nucleotide sequences were determined for the complete S genome segments of the six distinct hantavirus genotypes from Argentina and for two cell culture-isolated Andes virus strains from Chile. Phylogenetic analysis indicates that, although divergent from each other, all Argentinian hantavirus genotypes group together and form a novel phylogenetic clade with the Andes virus. The previously characterized South American hantaviruses Laguna

Marlene C. Bohlman; Sergey P. Morzunov; John Meissner; Mary Beth Taylor; Kimiko Ishibashi; Joan Rowe; Silvana Levis; Delia Enria

2002-01-01

133

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

E-print Network

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

Boyer, Edmond

134

A marked point process of rectangles and segments for automatic analysis of Digital Elevation Models.  

E-print Network

1 A marked point process of rectangles and segments for automatic analysis of Digital Elevation as realizations of a spatial point process of geometrical shapes. This framework allows the incorporation. Index Terms--Image processing, Poisson point process, stochastic geometry, dense urban area, Digital

Paris-Sud XI, Université de

135

Vessel Segmentation and Analysis in Laboratory Skin Transplant Micro-angiograms  

E-print Network

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

Lübeck, Universität zu

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, Taiwan 30043 3Department of Surgery, Cathay General Hospital, Taipei, Taiwan 4Cathay Medical Research Institute, Cathay General Hospital, Taipei, Taiwan 5Graduate Institute of Statistics, National Central

Lee, H.C. Paul

137

Human action segmentation and recognition via motion and shape analysis Ling Shao a,  

E-print Network

, which can detect different exercise types and count the exercise cycles in an indoor environment an automated video analysis system which addresses segmentation and detec- tion of human actions in an indoor into temporal cycles. We also apply a novel approach for human action recognition by describing human actions

Kim, Tae-Kyun

138

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.ding,guoliang.fan}@okstate.edu Abstract We present a generative model approach to explore in- trinsic semantic structures in sport videos mul- timedia and online database applications. Major benefits of video mining range from efficient

Fan, Guoliang

139

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

Microsoft Academic Search

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

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

1998-01-01

140

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

141

Market segmentation for multiple option healthcare delivery systems--an application of cluster analysis.  

PubMed

Healthcare providers of multiple option plans may be confronted with special market segmentation problems. This study demonstrates how cluster analysis may be used for discovering distinct patterns of preference for multiple option plans. The availability of metric, as opposed to categorical or ordinal, data provides the ability to use sophisticated analysis techniques which may be superior to frequency distributions and cross-tabulations in revealing preference patterns. PMID:10105775

Jarboe, G R; Gates, R H; McDaniel, C D

1990-01-01

142

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

Microsoft Academic Search

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

Fansan Zhu; Daniel Schneditz; Nathan W. Levin

1999-01-01

143

New Software for Market Segmentation Analysis: A Chi-Square Interaction Detector. AIR 1983 Annual Forum Paper.  

ERIC Educational Resources Information Center

The advantages and disadvantages of new software for market segmentation analysis are discussed, and the application of this new, chi-square based procedure (CHAID), is illustrated. A comparison is presented of an earlier, binary segmentation technique (THAID) and a multiple discriminant analysis. It is suggested that CHAID is superior to earlier…

Lay, Robert S.

144

Mean-Field Analysis of Recursive Entropic Segmentation of Biological Sequences  

NASA Astrophysics Data System (ADS)

Horizontal gene transfer in bacteria results in genomic sequences which are mosaic in nature. An important first step in the analysis of a bacterial genome would thus be to model the statistically nonstationary nucleotide or protein sequence with a collection of P stationary Markov chains, and partition the sequence of length N into M statistically stationary segments/domains. This can be done for Markov chains of order K = 0 using a recursive segmentation scheme based on the Jensen-Shannon divergence, where the unknown parameters P and M are estimated from a hypothesis testing/model selection process. In this talk, we describe how the Jensen-Shannon divergence can be generalized to Markov chains of order K > 0, as well as an algorithm optimizing the positions of a fixed number of domain walls. We then describe a mean field analysis of the generalized recursive Jensen-Shannon segmentation scheme, and show how most domain walls appear as local maxima in the divergence spectrum of the sequence, before highlighting the main problem associated with the recursive segmentation scheme, i.e. the strengths of the domain walls selected recursively do not decrease monotonically. This problem is especially severe in repetitive sequences, whose statistical signatures we will also discuss.

Cheong, Siew-Ann; Stodghill, Paul; Schneider, David; Myers, Christopher

2007-03-01

145

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

146

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

PubMed Central

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

2014-01-01

147

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

148

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

149

Analysis, design, and test of a graphite/polyimide Shuttle orbiter body flap segment  

NASA Technical Reports Server (NTRS)

For future missions, increases in Space Shuttle orbiter deliverable and recoverable payload weight capability may be needed. Such increases could be obtained by reducing the inert weight of the Shuttle. The application of advanced composites in orbiter structural components would make it possible to achieve such reductions. In 1975, NASA selected the orbiter body flap as a demonstration component for the Composite for Advanced Space Transportation Systems (CASTS) program. The progress made in 1977 through 1980 was integrated into a design of a graphite/polyimide (Gr/Pi) body flap technology demonstration segment (TDS). Aspects of composite body flap design and analysis are discussed, taking into account the direct-bond fibrous refractory composite insulation (FRCI) tile on Gr/Pi structure, Gr/Pi body flap weight savings, the body flap design concept, and composite body flap analysis. Details regarding the Gr/Pi technology demonstration segment are also examined.

Graves, S. R.; Morita, W. H.

1982-01-01

150

Sequence analysis of 12 genome segments of mud crab reovirus (MCRV).  

PubMed

Mud crab reovirus (MCRV) is the causative agent of a serious disease with high mortality in cultured mud crab (Scylla serrata). This study sequenced and analyzed 12 genome segments of MCRV. The 12 genome segments had a total length of 24.464 kb, showing a total G+C content of 41.29% and predicted 15 ORFs. Sequence analysis showed that the majority of MCRV genes shared low homology with the counterpart genes of other reoviruses, e.g., the amino acid identity of RNA-dependent RNA polymerase (RdRp) was lower than 13.0% compared to the RdRp sequences of other reoviruses. Nucleotide and amino acid sequences of RdRp and capping enzyme suggested MCRV as a single group. Further genome-based phylogenetical analysis of conserved termini and reovirus polymerase motif indicates that this MCRV belongs to a new genus of the Reoviridae family, tentatively named as Crabreovirus. PMID:22088215

Deng, Xie-xiong; Lü, Ling; Ou, Yu-jie; Su, Hong-jun; Li, Guang; Guo, Zhi-xun; Zhang, Rui; Zheng, Pei-rui; Chen, Yong-gui; He, Jian-guo; Weng, Shao-ping

2012-01-20

151

Segmental analysis for cocaine and metabolites by HPLC in hair of suspected drug overdose cases  

Microsoft Academic Search

Hair samples of eight postmortem cases were analyzed in segments of 1 to 3 cm for cocaine, benzoylecgonine and cocaethylene. Samples were prepared for analysis by digestion in 0.1 M HCl and subsequent extraction with mixed-mode solid-phase extraction columns. Measurement was made by reversed-phase, narrow-bore HPLC and fluorescence detection using two laboratory-made internal standards. The concentrations were in the region

Karine M Clauwaert; Jan F Van Bocxlaer; Willy E Lambert; André P De Leenheer

2000-01-01

152

Non-segmental analysis and synthesis based on a speech database  

Microsoft Academic Search

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

Andrew Slater; John Coleman

1996-01-01

153

Fully Bayesian inference for structural MRI: application to segmentation and statistical analysis of T2-hypointensities.  

PubMed

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: [Formula: see text]; range, [Formula: see text]). 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

154

Texture analysis based on the Hermite transform for image classification and segmentation  

NASA Astrophysics Data System (ADS)

Texture analysis has become an important task in image processing because it is used as a preprocessing stage in different research areas including medical image analysis, industrial inspection, segmentation of remote sensed imaginary, multimedia indexing and retrieval. In order to extract visual texture features a texture image analysis technique is presented based on the Hermite transform. Psychovisual evidence suggests that the Gaussian derivatives fit the receptive field profiles of mammalian visual systems. The Hermite transform describes locally basic texture features in terms of Gaussian derivatives. Multiresolution combined with several analysis orders provides detection of patterns that characterizes every texture class. The analysis of the local maximum energy direction and steering of the transformation coefficients increase the method robustness against the texture orientation. This method presents an advantage over classical filter bank design because in the latter a fixed number of orientations for the analysis has to be selected. During the training stage, a subset of the Hermite analysis filters is chosen in order to improve the inter-class separability, reduce dimensionality of the feature vectors and computational cost during the classification stage. We exhaustively evaluated the correct classification rate of real randomly selected training and testing texture subsets using several kinds of common used texture features. A comparison between different distance measurements is also presented. Results of the unsupervised real texture segmentation using this approach and comparison with previous approaches showed the benefits of our proposal.

Estudillo-Romero, Alfonso; Escalante-Ramirez, Boris; Savage-Carmona, Jesus

2012-06-01

155

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

156

Spectral Analysis of the Volume Operator in Loop Quantum Gravity  

NASA Astrophysics Data System (ADS)

We describe preliminary results of a detailed numerical analysis of the volume operator as formulated by Ashtekar and Lewandowski.2 Due to a simplified explicit expression for its matrix elements,3 it is possible for the first time to treat generic vertices of valence greater than four. It is found that the vertex geometry characterizes the volume spectrum.

Brunnemann, J.; Rideout, D.

2008-09-01

157

Coupled-wave analysis of apodized volume gratings  

E-print Network

for both uniform and apodized volume holograms based on rigorous coupled-wave analysis. We validate. We then apply our numerical model to calculate the spectral response of apodized gratings a method for creating apodization in volume holograms with approximately Gaussian spatial refractive index

Glebov, Leon

158

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

E-print Network

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

Magdeburg, Universität

159

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

160

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

161

Development and analysis of a linearly segmented CPC collector for industrial steam generation  

SciTech Connect

This study involves the design, analysis and construction of a modular, non-imaging, trough, concentrating solar collector for generation of process steam in a tropical climate. The most innovative feature of this concentrator is that the mirror surface consists of long and narrow planar segments placed inside sealed low-cost glass tubes. The absorber is a cylindrical fin inside an evacuated glass tube. As an extension of the same study, the optical efficiency of the segmented concentrator has been simulated by means of a Monte-Carlo Ray-Tracing program. Laser Ray-Tracing techniques were also used to evaluate the possibilities of this new concept. A preliminary evaluation of the experimental concentrator was done using a relatively simple method that combines results from two experimental measurements: overall heat loss coefficient and optical efficiency. A transient behaviour test was used to measure the overall heat loss coefficient throughout a wide range of temperatures.

Figueroa, J.A.A.

1980-06-01

162

Multivariate statistical analysis as a tool for the segmentation of 3D spectral data.  

PubMed

Acquisition of three-dimensional (3D) spectral data is nowadays common using many different microanalytical techniques. In order to proceed to the 3D reconstruction, data processing is necessary not only to deal with noisy acquisitions but also to segment the data in term of chemical composition. In this article, we demonstrate the value of multivariate statistical analysis (MSA) methods for this purpose, allowing fast and reliable results. Using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) coupled with a focused ion beam (FIB), a stack of spectrum images have been acquired on a sample produced by laser welding of a nickel-titanium wire and a stainless steel wire presenting a complex microstructure. These data have been analyzed using principal component analysis (PCA) and factor rotations. PCA allows to significantly improve the overall quality of the data, but produces abstract components. Here it is shown that rotated components can be used without prior knowledge of the sample to help the interpretation of the data, obtaining quickly qualitative mappings representative of elements or compounds found in the material. Such abundance maps can then be used to plot scatter diagrams and interactively identify the different domains in presence by defining clusters of voxels having similar compositions. Identified voxels are advantageously overlaid on secondary electron (SE) images with higher resolution in order to refine the segmentation. The 3D reconstruction can then be performed using available commercial softwares on the basis of the provided segmentation. To asses the quality of the segmentation, the results have been compared to an EDX quantification performed on the same data. PMID:24035679

Lucas, G; Burdet, P; Cantoni, M; Hébert, C

2013-01-01

163

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

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

164

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

165

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

PubMed

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 segment were employed in the analysis. Results showed considerable similarities between subjects in the kinetic control of trunk rotation about the spine's longitudinal axis, but variability in the control of trunk lean both to the side and forward. The kinetics of the throwing shoulder and elbow joint were comparable between subjects, but the contribution of the non-throwing upper limb was minimal and variable. The upper trunk rotators played a key role in accelerating the ball to an early, low velocity near stride foot contact. After a brief pause they resumed acting strongly in a positive direction, though not enough to prevent trunk angular velocity slowing, as the musculature of the arm applied a load at the throwing shoulder. The interaction moment from the proximal segments assisted the forearm extensor in slowing flexion and producing rapid elbow extension near ball release. The temporal onset of muscular torques was not in a strictly successive proximal-to-distal sequence. PMID:11228423

Hong, D A; Cheung, T K; Roberts, E M

2001-04-01

166

Automatic image registration through the segmentation of images pre-processed by joint histogram analysis  

NASA Astrophysics Data System (ADS)

A wide variety of automatic image registration methods have been proposed in the last years. However, under the scope of remote sensing applications, geometric correction is still mostly a manual work. A methodology for automatic image registration is proposed, which consists in three major steps: pre-processing, segmentation, and registration. The considered pre-processing is a new method, which is an iterative process based on a joint histogram analysis. Regarding the segmentation stage, global thresholding and a new method were used. The later comprises global thresholding and distance transforms in a single method. For both methods the following object properties were extracted: area, major and minor axis lengths of the adjusted ellipse and perimeter. The registration phase incorporates the matching of corresponding objects, a template matching technique to compute the distance between each pair of matched objects, and the computation of the transformation function parameters. The used dataset consisted in the pairs ETM+/ASTER, ETM+/SPOT and Orthophoto/IKONOS. The proposed methodology allows for the registration of a pair of images with translation and rotation effects, and to some extent with different spectral content, leading to a subpixel accuracy. Furthermore, it has been shown that the proposed pre-processing method allowed for the achievement of suitable segmented objects for later matching, even using global thresholding.

Gonçalves, Hernâni; Gonçalves, José A.; Corte-Real, Luís

2009-09-01

167

Automated system for ST segment and arrhythmia analysis in exercise radionuclide ventriculography  

SciTech Connect

A computer-based system for interpretation of the electrocardiogram (ECG) in the diagnosis of arrhythmia and ST segment abnormality in an exercise system is presented. The system was designed for inclusion in a gamma camera so the ECG diagnosis could be combined with the diagnostic capability of radionuclide ventriculography. Digitized data are analyzed in a beat-by-beat mode and a contextual diagnosis of underlying rhythm is provided. Each beat is assigned a beat code based on a combination of waveform analysis and RR interval measurement. The waveform analysis employs a new correlation coefficient formula which corrects for baseline wander. Selective signal averaging, in which only normal beats are included, is done for an improved signal-to-noise ratio prior to ST segment analysis. Template generation, R wave detection, QRS window size, baseline correction, and continuous updating of heart rate have all been automated. ST level and slope measurements are computed on signal-averaged data. Arrhythmia analysis of 13 passages of abnormal rhythm by computer was found to be correct in 98.4 percent of all beats. 25 passages of exercise data, 1-5 min in length, were evaluated by the cardiologist and found to be in agreement in 95.8 percent in measurements of ST level and 91.7 percent in measurements of ST slope.

Hsia, P.W.; Jenkins, J.M.; Shimoni, Y.; Gage, K.P.; Santinga, J.T.; Pitt, B.

1986-06-01

168

Spatial spectrum analysis of wave-front correction with a segmented mirror.  

PubMed

An expression is derived for the spatial power spectrum of wave-front errors after correction with a segmented mirror. This includes estimates of the spectral contributions of segment piston and tilt corrections and spatial aliasing by a regular array of segments. The approach allows rapid computation of wave-front error spectra in systems with highly segmented mirrors. PMID:12868805

Padin, Stephen

2003-07-01

169

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

170

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

171

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

PubMed Central

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

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

2013-01-01

172

Analysis of the ST-segment in terms of principal components: application on multichannel magnetocardiographic recordings.  

PubMed

Parameterization of the ST-segment is used as a tool for risk stratification for patients to suffer from ventricular tachycardia. This parameterization is performed in terms of Principal Component Analysis (PCA) applied on multichannel magnetocardiographic (MCG) recordings. 55-channel MCG was recorded from 14 normal persons, 10 patients with CHD, 14 patients with MI, and six patients with VT. We found a significantly (p < 0.05) lower PCA-score in patients with MI compared to normals. The lowest PCA-score was found in VT patients. Significant differences can be found between VT patients and normals and also between VT patients and CHD patients. PMID:14965858

Schless, B G; Müller, H-P; DeMelis, M; Pasquarelli, A; Erné, S N; Hombach, V

2004-01-01

173

Image segmentation and dynamic lineage analysis in single-cell fluorescence microscopy  

PubMed Central

An increasingly common component of studies in synthetic and systems biology is analysis of dynamics of gene expression at the single-cell level, a context that is heavily dependent on the use of time-lapse movies. Extracting quantitative data on the single-cell temporal dynamics from such movies remains a major challenge. Here, we describe novel methods for automating key steps in the analysis of single-cell, fluorescent images – segmentation and lineage reconstruction – to recognize and track individual cells over time. The automated analysis iteratively combines a set of extended morphological methods for segmentation, and uses a neighborhood-based scoring method for frame-to-frame lineage linking. Our studies with bacteria, budding yeast and human cells, demonstrate the portability and usability of these methods, whether using phase, bright field or fluorescent images. These examples also demonstrate the utility of our integrated approach in facilitating analyses of engineered and natural cellular networks in diverse settings. The automated methods are implemented in freely available, open-source software. PMID:19845017

Wang, Quanli; Niemi, Jarad; Tan, Chee-Meng; You, Lingchong; West, Mike

2009-01-01

174

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

175

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

PubMed Central

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

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

2014-01-01

176

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

177

Lagged segmented Poincaré plot analysis for risk stratification in patients with dilated cardiomyopathy.  

PubMed

The objectives of this study were to introduce a new type of heart-rate variability analysis improving risk stratification in patients with idiopathic dilated cardiomyopathy (DCM) and to provide additional information about impaired heart beat generation in these patients. Beat-to-beat intervals (BBI) of 30-min ECGs recorded from 91 DCM patients and 21 healthy subjects were analyzed applying the lagged segmented Poincaré plot analysis (LSPPA) method. LSPPA includes the Poincaré plot reconstruction with lags of 1-100, rotating the cloud of points, its normalized segmentation adapted to their standard deviations, and finally, a frequency-dependent clustering. The lags were combined into eight different clusters representing specific frequency bands within 0.012-1.153 Hz. Statistical differences between low- and high-risk DCM could be found within the clusters II-VIII (e.g., cluster IV: 0.033-0.038 Hz; p = 0.0002; sensitivity = 85.7 %; specificity = 71.4 %). The multivariate statistics led to a sensitivity of 92.9 %, specificity of 85.7 % and an area under the curve of 92.1 % discriminating these patient groups. We introduced the LSPPA method to investigate time correlations in BBI time series. We found that LSPPA contributes considerably to risk stratification in DCM and yields the highest discriminant power in the low and very low-frequency bands. PMID:22689265

Voss, Andreas; Fischer, Claudia; Schroeder, Rico; Figulla, Hans R; Goernig, Matthias

2012-07-01

178

Programming model Network Structue Analysis of the Cost-Effectiveness of Fish Tagging Technologies and Programs Segment code Segment Name RKM  

E-print Network

and Programs Segment code Segment Name RKM 1 1 Segment bifurcations COLR1 Lower Columbia 29 29 Segment of river SNAK 12 SALMF5 Pahsimeroi 1,318 X X SNAK 12 SALMF6 Upper Salmon 1,427 X X #12;CRIPTION FEBRUARY 13, 201

179

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

180

Segmentation and visual analysis of whole-body mouse skeleton microSPECT.  

PubMed

Whole-body SPECT small animal imaging is used to study cancer, and plays an important role in the development of new drugs. Comparing and exploring whole-body datasets can be a difficult and time-consuming task due to the inherent heterogeneity of the data (high volume/throughput, multi-modality, postural and positioning variability). The goal of this study was to provide a method to align and compare side-by-side multiple whole-body skeleton SPECT datasets in a common reference, thus eliminating acquisition variability that exists between the subjects in cross-sectional and multi-modal studies. Six whole-body SPECT/CT datasets of BALB/c mice injected with bone targeting tracers (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) and (99m)Tc-hydroxymethane diphosphonate ((99m)Tc-HDP) were used to evaluate the proposed method. An articulated version of the MOBY whole-body mouse atlas was used as a common reference. Its individual bones were registered one-by-one to the skeleton extracted from the acquired SPECT data following an anatomical hierarchical tree. Sequential registration was used while constraining the local degrees of freedom (DoFs) of each bone in accordance to the type of joint and its range of motion. The Articulated Planar Reformation (APR) algorithm was applied to the segmented data for side-by-side change visualization and comparison of data. To quantitatively evaluate the proposed algorithm, bone segmentations of extracted skeletons from the correspondent CT datasets were used. Euclidean point to surface distances between each dataset and the MOBY atlas were calculated. The obtained results indicate that after registration, the mean Euclidean distance decreased from 11.5±12.1 to 2.6±2.1 voxels. The proposed approach yielded satisfactory segmentation results with minimal user intervention. It proved to be robust for "incomplete" data (large chunks of skeleton missing) and for an intuitive exploration and comparison of multi-modal SPECT/CT cross-sectional mouse data. PMID:23152834

Khmelinskii, Artem; Groen, Harald C; Baiker, Martin; de Jong, Marion; Lelieveldt, Boudewijn P F

2012-01-01

181

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

182

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

183

Chapman-Enskog Analysis of Finite Volume Lattice Boltzmann Schemes  

E-print Network

In this paper, we provide a systematic analysis of some finite volume lattice Boltzmann schemes in two dimensions. A complete iteration cycle in time evolution of discretized distribution functions is formally divided into collision and propagation (streaming) steps. Considering mass and momentum conserving properties of the collision step, it becomes obvious that changes in the momentum of finite volume cells is just due to the propagation step. Details of the propagation step are discussed for different approximate schemes for the evaluation of fluxes at the boundaries of the finite volume cells. Moreover, a full Chapman-Enskog analysis is conducted allowing to recover the Navier-Stokes equation. As an important result of this analysis, the relation between the lattice Boltzmann relaxation time and the kinematic viscosity of the fluid is derived for each approximate flux evaluation scheme. In particular, it is found that the constant upwind scheme leads to a positive numerical viscosity while the central sc...

Siboni, Nima H; Varnik, Fathollah

2014-01-01

184

Dynamic customer segmentation analysis based on customer value in electronic business environment  

Microsoft Academic Search

In this paper, we broaden traditional marketplace segmentation index by creating a dynamic index system based on customer value, as in today's changing electronic business environment, customer purchasing behavior is more complicated, diversified and fast changing with more channels to choose. BP neural network is applied to create dynamic customer segmentation model. This segmentation model helps to categorize customer type

Peng Jia; Li Changqing; Liu Jia

2011-01-01

185

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

186

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

187

Spectral analysis program. Volume 1: User's guide  

NASA Technical Reports Server (NTRS)

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

Hayden, W. L.

1972-01-01

188

Analysis of vocal folds movement in high speed videoendoscopy based on level set segmentation and image registration  

Microsoft Academic Search

Computer analysis of high-speed videoendoscopy (HSV) recordings is becoming increasingly useful in functional evaluation of vocal fold pathology. In this work we present two new approaches for the vocal fold HSV-based analysis that have not been previously reported. First, segmentation of vocal fold edges is performed in our method using the level set algorithm. Second, having two vocal fold contours

Andrzej Skalski; T. Zielinki; Dimitar Deliyski

2008-01-01

189

Automated 3D Segmentation of Intraretinal Surfaces in SD-OCT Volumes in Normal and Diabetic Mice  

PubMed Central

Purpose To describe an adaptation of an existing graph-theoretic method (initially developed for human optical coherence tomography [OCT] images) for the three-dimensional (3D) automated segmentation of 10 intraretinal surfaces in mice scans, and assess the accuracy of the method and the reproducibility of thickness measurements. Methods Ten intraretinal surfaces were segmented in repeat spectral domain (SD)-OCT volumetric images acquired from normal (n = 8) and diabetic (n = 10) mice. The accuracy of the method was assessed by computing the border position errors of the automated segmentation with respect to manual tracings obtained from two experts. The reproducibility was statistically assessed for four retinal layers within eight predefined regions using the mean and SD of the differences in retinal thickness measured in the repeat scans, the coefficient of variation (CV) and the intraclass correlation coefficients (ICC; with 95% confidence intervals [CIs]). Results The overall mean unsigned border position error for the 10 surfaces computed over 97 B-scans (10 scans, 10 normal mice) was 3.16 ± 0.91 ?m. The overall mean differences in retinal thicknesses computed from the normal and diabetic mice were 1.86 ± 0.95 and 2.15 ± 0.86 ?m, respectively. The CV of the retinal thicknesses for all the measured layers ranged from 1.04% to 5%. The ICCs for the total retinal thickness in the normal and diabetic mice were 0.78 [0.10, 0.92] and 0.83 [0.31, 0.96], respectively. Conclusion The presented method (publicly available as part of the Iowa Reference Algorithms) has acceptable accuracy and reproducibility and is expected to be useful in the quantitative study of intraretinal layers in mice. Translational Relevance The presented method, initially developed for human OCT, has been adapted for mice, with the potential to be adapted for other animals as well. Quantitative in vivo assessment of the retina in mice allows changes to be measured longitudinally, decreasing the need for them. PMID:25346873

Antony, Bhavna J.; Jeong, Woojin; Abramoff, Michael D.; Vance, Joseph; Sohn, Elliott H.; Garvin, Mona K.

2014-01-01

190

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

191

Principle component analysis on photoplethysmograms: blood oxygen saturation estimation and signal segmentation.  

PubMed

Most pulse oximeters determine blood oxygen saturation (SpO(2)) after calculating a coefficient, R, that represents the normalized ratiometric contributions of the pulsatile red and near-infrared photoplethysmograms (PPGs) acquired by the sensor. This paper presents a new approach that uses principle component analysis (PCA) to separate the signal and noise components of unfiltered PPGs and provide the determination of R. Also, rather than use peak-to-valley time intervals to obtain R, this technique uses eigenvalue and eigenvector data obtained during PCA to optimize these time intervals and improve the R calculation. Early analyses on unfiltered PPGs from 16 subjects indicate that these R values compare to those obtained from FFT-based methods and yield SpO(2) values consistent with those reported by a commercial unit. All signal data are considered during the PCA process, so this technique shows promise to precisely segment clean versus noise-corrupted PPGs. PMID:22255992

Li, Kejia; Warren, Steve

2011-01-01

192

A model-based circular binary segmentation algorithm for the analysis of array CGH data  

PubMed Central

Background Circular Binary Segmentation (CBS) is a permutation-based algorithm for array Comparative Genomic Hybridization (aCGH) data analysis. CBS accurately segments data by detecting change-points using a maximal-t test; but extensive computational burden is involved for evaluating the significance of change-points using permutations. A recent implementation utilizing a hybrid method and early stopping rules (hybrid CBS) to improve the performance in speed was subsequently proposed. However, a time analysis revealed that a major portion of computation time of the hybrid CBS was still spent on permutation. In addition, what the hybrid method provides is an approximation of the significance upper bound or lower bound, not an approximation of the significance of change-points itself. Results We developed a novel model-based algorithm, extreme-value based CBS (eCBS), which limits permutations and provides robust results without loss of accuracy. Thousands of aCGH data under null hypothesis were simulated in advance based on a variety of non-normal assumptions, and the corresponding maximal-t distribution was modeled by the Generalized Extreme Value (GEV) distribution. The modeling results, which associate characteristics of aCGH data to the GEV parameters, constitute lookup tables (eXtreme model). Using the eXtreme model, the significance of change-points could be evaluated in a constant time complexity through a table lookup process. Conclusions A novel algorithm, eCBS, was developed in this study. The current implementation of eCBS consistently outperforms the hybrid CBS 4× to 20× in computation time without loss of accuracy. Source codes, supplementary materials, supplementary figures, and supplementary tables can be found at http://ntumaps.cgm.ntu.edu.tw/eCBSsupplementary. PMID:21985277

2011-01-01

193

Segmentation of Fluorescence Microscopy Images for Quantitative Analysis of Cell Nuclear Architecture  

PubMed Central

Abstract Considerable advances in microscopy, biophysics, and cell biology have provided a wealth of imaging data describing the functional organization of the cell nucleus. Until recently, cell nuclear architecture has largely been assessed by subjective visual inspection of fluorescently labeled components imaged by the optical microscope. This approach is inadequate to fully quantify spatial associations, especially when the patterns are indistinct, irregular, or highly punctate. Accurate image processing techniques as well as statistical and computational tools are thus necessary to interpret this data if meaningful spatial-function relationships are to be established. Here, we have developed a thresholding algorithm, stable count thresholding (SCT), to segment nuclear compartments in confocal laser scanning microscopy image stacks to facilitate objective and quantitative analysis of the three-dimensional organization of these objects using formal statistical methods. We validate the efficacy and performance of the SCT algorithm using real images of immunofluorescently stained nuclear compartments and fluorescent beads as well as simulated images. In all three cases, the SCT algorithm delivers a segmentation that is far better than standard thresholding methods, and more importantly, is comparable to manual thresholding results. By applying the SCT algorithm and statistical analysis, we quantify the spatial configuration of promyelocytic leukemia nuclear bodies with respect to irregular-shaped SC35 domains. We show that the compartments are closer than expected under a null model for their spatial point distribution, and furthermore that their spatial association varies according to cell state. The methods reported are general and can readily be applied to quantify the spatial interactions of other nuclear compartments. PMID:19383481

Russell, Richard A.; Adams, Niall M.; Stephens, David A.; Batty, Elizabeth; Jensen, Kirsten; Freemont, Paul S.

2009-01-01

194

A new approach of graph cuts based segmentation for thermal IR image analysis  

NASA Astrophysics Data System (ADS)

Thermal Infra Red images are one of the most investigated and popular data modalities whose usage has grown exponentially from humble origins to being one of the most extensively harnessed imaging forms. Instead of capturing the radiometry in visible spectra, the thermal Images focus on the near to mid Infrared spectra thereby producing a scene structure quite different from their visual counterpart images. Also traditionally the spatial resolution of the infra red images has been typically lower than traditional color images. The above reasons have contributed to the past trend of minimal automated analysis of thermal images wherein intensity (which corresponds to heat content) and to a lesser extent spatiality formed the primary features of interest in an IR image. In this work we extend the automated processing of Infra red images by using an advanced image analysis technique called Graph cuts. Graph cuts have the unique property of providing global optimal segmentation which has contributed to its popularity. We side step the extensive computational requirements of a Graph cuts procedure (which consider pixels as the vertices of graphs) by performing preprocessing by performing initial segmentation to obtain a short list of candidate regions. Features extracted on the candidate regions are then used as an input for the graph cut procedure. Appropriate energy functions are used to combine traditionally used graph cuts feature like intensity feature with new salient features like gradients. The results show the effectiveness of using the above technique for automated processing of thermal infrared images especially when compared with traditional techniques like intensity thresholding.

Hu, Xuezhang; Chakravarty, Sumit

2012-12-01

195

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

196

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

197

Cost-Volume-Profit Analysis Adjusted for Learning  

Microsoft Academic Search

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

E. V. McIntyre

1977-01-01

198

An extensive log-file analysis of step-and-shoot intensity modulated radiation therapy segment delivery errors.  

PubMed

We present a study to evaluate the monitor unit (MU), dosimetric, and leaf-motion errors found in the delivery of 91 step-and-shoot IMRT treatment plans performed at three nominal dose rates using a dual modality high energy Linac (Varian 2100 C/D, Varian Medical Systems Inc., Palo Alto, CA) equipped with a 120-leaf multileaf collimator (MLC). The analysis was performed by studying log files generated by the MLC controller system. Recent studies by our group have validated that the automatically generated MLC log files accurately record the actual system delivery. A total of 635 beams were delivered at three nominal dose rates: 100, 300, and 600 MU/min. The log files were manually retrieved and analysis software was developed to extract the recorded MU delivery and leaf positions for each segment. Our analysis revealed that the magnitude of segment MU errors were independent of the planned segment MUs. Segment MU errors were found to increase with dose rate having maximum errors per segment of +/-1.8 MU at 600 MU/min, +/-0.8 MU at 300 MU/min, and +/-0.5 MU at 100 MU/min. The total absolute MU error in each plan was observed to increase with the number of plan segments, with the trend increasing more rapidly for higher dose rates. Three dimensional dose distributions were recomputed based on the observed segment MU errors for three plans with large cumulative absolute MU errors. Comparison with the original treatment plans indicated no clinically significant consequences due to these errors. In addition, approximately 80% of the total segment deliveries reported at least one collimator leaf moving at least 1 mm (projected at isocenter) during segment delivery. Such errors occur near the end of segment delivery and have been previously observed by our group using a fast video-based electronic portal imaging device. At 600 MU/min, between 5% and 23% of the plan MUs were delivered during leaf motion that had exceeded a 1 mm position tolerance. These leaf motion errors were not included in the treatment plan recalculations performed in this study. PMID:15259664

Stell, Anthony M; Li, Jonathan G; Zeidan, Omar A; Dempsey, James F

2004-06-01

199

Segmentation propagation using a 3D embryo atlas for high-throughput MRI phenotyping: comparison and validation with manual segmentation.  

PubMed

Effective methods for high-throughput screening and morphometric analysis are crucial for phenotyping the increasing number of mouse mutants that are being generated. Automated segmentation propagation for embryo phenotyping is an emerging application that enables noninvasive and rapid quantification of substructure volumetric data for morphometric analysis. We present a study to assess and validate the accuracy of brain and kidney volumes generated via segmentation propagation in an ex vivo mouse embryo MRI atlas comprising three different groups against the current "gold standard"--manual segmentation. Morphometric assessment showed good agreement between automatically and manually segmented volumes, demonstrating that it is possible to assess volumes for phenotyping a population of embryos using segmentation propagation with the same variation as manual segmentation. As part of this study, we have made our average atlas and segmented volumes freely available to the community for use in mouse embryo phenotyping studies. These MRI datasets and automated methods of analyses will be essential for meeting the challenge of high-throughput, automated embryo phenotyping. PMID:22556102

Norris, Francesca C; Modat, Marc; Cleary, Jon O; Price, Anthony N; McCue, Karen; Scambler, Peter J; Ourselin, Sebastien; Lythgoe, Mark F

2013-03-01

200

VascuSynth: simulating vascular trees for generating volumetric image data with ground-truth segmentation and tree analysis.  

PubMed

Automated segmentation and analysis of tree-like structures from 3D medical images are important for many medical applications, such as those dealing with blood vasculature or lung airways. However, there is an absence of large databases of expert segmentations and analyses of such 3D medical images, which impedes the validation and training of proposed image analysis algorithms. In this work, we simulate volumetric images of vascular trees and generate the corresponding ground-truth segmentations, bifurcation locations, branch properties, and tree hierarchy. The tree generation is performed by iteratively growing a vascular structure based on a user-defined (possibly spatially varying) oxygen demand map. We describe the details of the algorithm and provide a variety of example results. PMID:20656456

Hamarneh, Ghassan; Jassi, Preet

2010-12-01

201

Standard guide for measuring the wear volumes of piston ring segments run against flat coupons in reciprocating wear tests  

E-print Network

1.1 This guide covers and describes a profiling method for use accurately measuring the wear loss of compound-curved (crowned) piston ring specimens that run against flat counterfaces. It does not assume that the wear scars are ideally flat, as do some alternative measurement methods. Laboratory-scale wear tests have been used to evaluate the wear of materials, coatings, and surface treatments that are candidates for piston rings and cylinder liners in diesel engines or spark ignition engines. Various loads, temperatures, speeds, lubricants, and durations are used for such tests, but some of them use a curved piston ring segment as one sliding partner and a flat or curved specimen (simulating the cylinder liner) as its counterface. The goal of this guide is to provide more accurate wear measurements than alternative approaches involving weight loss or simply measuring the length and width of the wear marks. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its ...

American Society for Testing and Materials. Philadelphia

2011-01-01

202

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

203

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

204

Identifying Like-Minded Audiences for Global Warming Public Engagement Campaigns: An Audience Segmentation Analysis and Tool Development  

PubMed Central

Background Achieving national reductions in greenhouse gas emissions will require public support for climate and energy policies and changes in population behaviors. Audience segmentation – a process of identifying coherent groups within a population – can be used to improve the effectiveness of public engagement campaigns. Methodology/Principal Findings In Fall 2008, we conducted a nationally representative survey of American adults (n?=?2,164) to identify audience segments for global warming public engagement campaigns. By subjecting multiple measures of global warming beliefs, behaviors, policy preferences, and issue engagement to latent class analysis, we identified six distinct segments ranging in size from 7 to 33% of the population. These six segments formed a continuum, from a segment of people who were highly worried, involved and supportive of policy responses (18%), to a segment of people who were completely unconcerned and strongly opposed to policy responses (7%). Three of the segments (totaling 70%) were to varying degrees concerned about global warming and supportive of policy responses, two (totaling 18%) were unsupportive, and one was largely disengaged (12%), having paid little attention to the issue. Certain behaviors and policy preferences varied greatly across these audiences, while others did not. Using discriminant analysis, we subsequently developed 36-item and 15-item instruments that can be used to categorize respondents with 91% and 84% accuracy, respectively. Conclusions/Significance In late 2008, Americans supported a broad range of policies and personal actions to reduce global warming, although there was wide variation among the six identified audiences. To enhance the impact of campaigns, government agencies, non-profit organizations, and businesses seeking to engage the public can selectively target one or more of these audiences rather than address an undifferentiated general population. Our screening instruments are available to assist in that process. PMID:21423743

Maibach, Edward W.; Leiserowitz, Anthony; Roser-Renouf, Connie; Mertz, C. K.

2011-01-01

205

Quantitative Analysis of the Drosophila Segmentation Regulatory Network Using Pattern Generating Potentials  

PubMed Central

Cis-regulatory modules that drive precise spatial-temporal patterns of gene expression are central to the process of metazoan development. We describe a new computational strategy to annotate genomic sequences based on their “pattern generating potential” and to produce quantitative descriptions of transcriptional regulatory networks at the level of individual protein-module interactions. We use this approach to convert the qualitative understanding of interactions that regulate Drosophila segmentation into a network model in which a confidence value is associated with each transcription factor-module interaction. Sequence information from multiple Drosophila species is integrated with transcription factor binding specificities to determine conserved binding site frequencies across the genome. These binding site profiles are combined with transcription factor expression information to create a model to predict module activity patterns. This model is used to scan genomic sequences for the potential to generate all or part of the expression pattern of a nearby gene, obtained from available gene expression databases. Interactions between individual transcription factors and modules are inferred by a statistical method to quantify a factor's contribution to the module's pattern generating potential. We use these pattern generating potentials to systematically describe the location and function of known and novel cis-regulatory modules in the segmentation network, identifying many examples of modules predicted to have overlapping expression activities. Surprisingly, conserved transcription factor binding site frequencies were as effective as experimental measurements of occupancy in predicting module expression patterns or factor-module interactions. Thus, unlike previous module prediction methods, this method predicts not only the location of modules but also their spatial activity pattern and the factors that directly determine this pattern. As databases of transcription factor specificities and in vivo gene expression patterns grow, analysis of pattern generating potentials provides a general method to decode transcriptional regulatory sequences and networks. PMID:20808951

Richards, Adam; McCutchan, Michael; Wakabayashi-Ito, Noriko; Hammonds, Ann S.; Celniker, Susan E.; Kumar, Sudhir; Wolfe, Scot A.; Brodsky, Michael H.; Sinha, Saurabh

2010-01-01

206

Sequence Analysis of the Segmental Duplication Responsible for Paris Sex-Ratio Drive in Drosophila simulans  

PubMed Central

Sex-ratio distorters are X-linked selfish genetic elements that facilitate their own transmission by subverting Mendelian segregation at the expense of the Y chromosome. Naturally occurring cases of sex-linked distorters have been reported in a variety of organisms, including several species of Drosophila; they trigger genetic conflict over the sex ratio, which is an important evolutionary force. However, with a few exceptions, the causal loci are unknown. Here, we molecularly characterize the segmental duplication involved in the Paris sex-ratio system that is still evolving in natural populations of Drosophila simulans. This 37.5 kb tandem duplication spans six genes, from the second intron of the Trf2 gene (TATA box binding protein-related factor 2) to the first intron of the org-1 gene (optomotor-blind-related-gene-1). Sequence analysis showed that the duplication arose through the production of an exact copy on the template chromosome itself. We estimated this event to be less than 500 years old. We also detected specific signatures of the duplication mechanism; these support the Duplication-Dependent Strand Annealing model. The region at the junction between the two duplicated segments contains several copies of an active transposable element, Hosim1, alternating with 687 bp repeats that are noncoding but transcribed. The almost-complete sequence identity between copies made it impossible to complete the sequencing and assembly of this region. These results form the basis for the functional dissection of Paris sex-ratio drive and will be valuable for future studies designed to better understand the dynamics and the evolutionary significance of sex chromosome drive. PMID:22384350

Fouvry, Lucie; Ogereau, David; Berger, Anne; Gavory, Frederick; Montchamp-Moreau, Catherine

2011-01-01

207

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

PubMed

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

Jakobsson, Gerd; Kronstrand, Robert

2014-06-01

208

Method for measuring anterior chamber volume by image analysis  

NASA Astrophysics Data System (ADS)

Anterior chamber volume (ACV) is very important for an oculist to make rational pathological diagnosis as to patients who have some optic diseases such as glaucoma and etc., yet it is always difficult to be measured accurately. In this paper, a method is devised to measure anterior chamber volumes based on JPEG-formatted image files that have been transformed from medical images using the anterior-chamber optical coherence tomographer (AC-OCT) and corresponding image-processing software. The corresponding algorithms for image analysis and ACV calculation are implemented in VC++ and a series of anterior chamber images of typical patients are analyzed, while anterior chamber volumes are calculated and are verified that they are in accord with clinical observation. It shows that the measurement method is effective and feasible and it has potential to improve accuracy of ACV calculation. Meanwhile, some measures should be taken to simplify the handcraft preprocess working as to images.

Zhai, Gaoshou; Zhang, Junhong; Wang, Ruichang; Wang, Bingsong; Wang, Ningli

2007-12-01

209

Integrated segmentation of cellular structures  

NASA Astrophysics Data System (ADS)

Automatic segmentation of cellular structures is an essential step in image cytology and histology. Despite substantial progress, better automation and improvements in accuracy and adaptability to novel applications are needed. In applications utilizing multi-channel immuno-fluorescence images, challenges include misclassification of epithelial and stromal nuclei, irregular nuclei and cytoplasm boundaries, and over and under-segmentation of clustered nuclei. Variations in image acquisition conditions and artifacts from nuclei and cytoplasm images often confound existing algorithms in practice. In this paper, we present a robust and accurate algorithm for jointly segmenting cell nuclei and cytoplasm using a combination of ideas to reduce the aforementioned problems. First, an adaptive process that includes top-hat filtering, Eigenvalues-of-Hessian blob detection and distance transforms is used to estimate the inverse illumination field and correct for intensity non-uniformity in the nuclei channel. Next, a minimum-error-thresholding based binarization process and seed-detection combining Laplacian-of-Gaussian filtering constrained by a distance-map-based scale selection is used to identify candidate seeds for nuclei segmentation. The initial segmentation using a local maximum clustering algorithm is refined using a minimum-error-thresholding technique. Final refinements include an artifact removal process specifically targeted at lumens and other problematic structures and a systemic decision process to reclassify nuclei objects near the cytoplasm boundary as epithelial or stromal. Segmentation results were evaluated using 48 realistic phantom images with known ground-truth. The overall segmentation accuracy exceeds 94%. The algorithm was further tested on 981 images of actual prostate cancer tissue. The artifact removal process worked in 90% of cases. The algorithm has now been deployed in a high-volume histology analysis application.

Ajemba, Peter; Al-Kofahi, Yousef; Scott, Richard; Donovan, Michael; Fernandez, Gerardo

2011-03-01

210

Quantitative analysis of volume images: electron microscopic tomography of HIV  

NASA Astrophysics Data System (ADS)

Three-dimensional objects should be represented by 3D images. So far, most of the evaluation of images of 3D objects have been done visually, either by looking at slices through the volumes or by looking at 3D graphic representations of the data. In many applications a more quantitative evaluation would be valuable. Our application is the analysis of volume images of the causative agent of the acquired immune deficiency syndrome (AIDS), namely human immunodeficiency virus (HIV), produced by electron microscopic tomography (EMT). A structural analysis of the virus is of importance. The representation of some of the interesting structural features will depend on the orientation and the position of the object relative to the digitization grid. We describe a method of defining orientation and position of objects based on the moment of inertia of the objects in the volume image. In addition to a direct quantification of the 3D object a quantitative description of the convex deficiency may provide valuable information about the geometrical properties. The convex deficiency is the volume object subtracted from its convex hull. We describe an algorithm for creating an enclosing polyhedron approximating the convex hull of an arbitrarily shaped object.

Nystroem, Ingela; Bengtsson, Ewert W.; Nordin, Bo G.; Borgefors, Gunilla

1994-05-01

211

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

NASA Astrophysics Data System (ADS)

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

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

1989-04-01

212

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

213

Unconventional Word Segmentation in Emerging Bilingual Students' Writing: A Longitudinal Analysis  

ERIC Educational Resources Information Center

This study explores cross-language and longitudinal patterns in unconventional word segmentation in 25 emerging bilingual students' (Spanish/English) writing from first through third grade. Spanish and English writing samples were collected annually and analyzed for two basic types of unconventional word segmentation: hyposegmentation, in…

Sparrow, Wendy

2014-01-01

214

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

215

Market Segmentation Analysis Using Attitudes Toward Transportation: Exploring the Differences Between Men and Women  

Microsoft Academic Search

Traveler attitudes and preferences as well as demographic variables are important components of travel behavior. By using travel attitudes, factor and cluster analyses were conducted to segment the sample. Six distinct groups were extracted: transit enthusiasts, anxious status seekers, carless riders, green cruisers, frugal travelers, and obstinate drivers. The segments showed unique combinations of attitudes with distinct travel behaviors and

Gabriela Beirao; Jose Sarsfield Cabral

2008-01-01

216

Application of gray relative analysis method in the market segment alternatives of auto components  

Microsoft Academic Search

With the increasingly keen competition of automobile market, the auto component enterprises pay more and more attention to the market segment alternatives, in order to suit the demand of market. Market segment is the important step of the alternatives of target market, and the key factor related to the success of the enterprises. Thus it becomes an important assignment the

Hong-li Yu; Yan Yu

2010-01-01

217

Broadcast news story segmentation using social network analysis and hidden markov models  

Microsoft Academic Search

This paper presents an approach for the segmentation of broadcast news into stories. The main novelty of this work is that the segmentation process does not take into account the content of the news, i.e. what is said, but rather the structure of the social relationships between the persons that in the news are involved. The main rationale behind such

Alessandro Vinciarelli; Sarah Favre

2007-01-01

218

LEARNING TO SEGMENT SONGS WITH ORDINAL LINEAR DISCRIMINANT ANALYSIS Brian McFee  

E-print Network

genres or styles. Pop music relies heavily on a verse/chorus structure, and is well characterized method is applied to music segmen- tation, in which a song is partitioned into functional or locally-- Music, automatic segmentation, learning 1. INTRODUCTION Automatic music segmentation algorithms take

Ellis, Dan

219

Concept Area Two Objectives and Test Items (Rev.) Part One, Part Two. Economic Analysis Course. Segments 17-49.  

ERIC Educational Resources Information Center

A multimedia course in economic analysis was developed and used in conjunction with the United States Naval Academy. (See ED 043 790 and ED 043 791 for final reports of the project evaluation and development model.) This report deals with the second concept area of the course and focuses on macroeconomics. Segments 17 through 49 are presented,…

Sterling Inst., Washington, DC. Educational Technology Center.

220

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

PubMed Central

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

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

2013-01-01

221

Segmenting consumers based on how they spend a tax rebate: An analysis of the Australian stimulus payment  

Microsoft Academic Search

Tax rebates are instruments for stimulating consumer spending during recessions. Previous research assessed whether consumers use tax rebates for saving or, alternatively, purchasing goods and services. These studies concentrated on aggregate estimations. Based on the saving motive hierarchy suggested in the economic psychology literature, other theories on saving motives, and acquisition pattern analysis, we propose that consumers can be segmented

Harmen Oppewal; Leonard J. Paas; Geoffrey I. Crouch; Twan Huybers

2010-01-01

222

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

223

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

PubMed

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

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

2014-08-01

224

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

225

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

226

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

227

Three-dimensional freehand ultrasound: Image reconstruction and volume analysis  

Microsoft Academic Search

A system is described that rapidly produces a regular 3-dimensional (3-D) data block suitable for processing by conventional image analysis and volume measurement software. The system uses electromagnetic spatial location of 2-dimensional (2-D) freehand-scanned ultrasound B-mode images, custom-built signal-conditioning hardware, UNIX-based computer processing and an efficient 3-D reconstruction algorithm. Utilisation of images from multiple angles of insonation, “compounding”, reduces speckle

C. D. Barry; C. P. Allott; N. W. John; P. M. Mellor; P. A. Arundel; D. S. Thomson; J. C. Waterton

1997-01-01

228

The finite volume flic method and its stability analysis  

Microsoft Academic Search

In this study, a general finite volume Fluid-in-cell method (FVFLIC) for solving the Navier—Stokes equations is introduced. The stability of the numerical method is then analysed by directly using two-dimensional Euler equations instead of a linear model equation. This direct approach to the analysis of non-linear stability is based on the Taylor expansion of the discretized Euler equations and some

Y Mao; D. E Winterbone

1995-01-01

229

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

230

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

231

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

PubMed Central

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

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

2013-01-01

232

Study on the application of MRF and the D-S theory to image segmentation of the human brain and quantitative analysis of the brain tissue  

NASA Astrophysics Data System (ADS)

The features of the spatial information of Markov random field image was used in image segmentation. It can effectively remove the noise, and get a more accurate segmentation results. Based on the fuzziness and clustering of pixel grayscale information, we find clustering center of the medical image different organizations and background through Fuzzy cmeans clustering method. Then we find each threshold point of multi-threshold segmentation through two dimensional histogram method, and segment it. The features of fusing multivariate information based on the Dempster-Shafer evidence theory, getting image fusion and segmentation. This paper will adopt the above three theories to propose a new human brain image segmentation method. Experimental result shows that the segmentation result is more in line with human vision, and is of vital significance to accurate analysis and application of tissues.

Guan, Yihong; Luo, Yatao; Yang, Tao; Qiu, Lei; Li, Junchang

2012-01-01

233

Effect-directed analysis by high-performance liquid chromatography with gas-segmented enzyme inhibition.  

PubMed

A reversed-phase high-performance liquid chromatography system with UV-detector was equipped with an on-line acetylcholinesterase inhibition assay to achieve effect-directed analysis of potentially toxic samples. The enzyme activity was detected colorimetrically using Ellman's reagent. The inhibition and substrate conversion took place in glass capillaries at a 100 microL/min flow rate. Extra-column band spreading in the reaction coils reduces the sensitivity and separation power of biochemical detectors severely. Knitted reactors exhibited no reduction of longitudinal dispersion in the tested flow range. The implementation of air-segmentation allowed an extended inhibition and substrate conversion time without a significant loss of chromatographic resolution. The limit of detection of two model compounds carbofuran (carbamate) and paraoxon-ethyl (organophosphate) was determined to be 13 ng (injected mass) and 7.4 ng, respectively, applying an isocratic chromatography method. A mixture of five insecticides was separated by a gradient elution and the inhibitory effect on the enzyme activity could be detected with high resolution. The band width at half height of the enzyme inhibition detector signal after a reaction time of about 8 min or 4.2 m of capillary, respectively, increased only by a factor of 1.4 compared to the UV-detector signal. PMID:16197955

Fabel, Susanne; Niessner, Reinhard; Weller, Michael G

2005-12-16

234

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

235

Magnetic field analysis of Lorentz motors using a novel segmented magnetic equivalent circuit method.  

PubMed

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

236

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

PubMed Central

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

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

2014-01-01

237

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

238

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

239

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

E-print Network

) noninvasively. Dynamic images of the GI tract after oral gavage with a Gd contrast agent were acquired at a rate that propagates the chyme from the oral to aboral ends of the GI tract. In contrast, segmental motions represent

Brasseur, James G.

240

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

Microsoft Academic Search

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

P. C. Siddalingaswamy; K. Gopalakrishna Prabhu

241

Analysis of DNA Sequences through Segmentation: Exploring the Mosaic via Statistical Measures  

NASA Astrophysics Data System (ADS)

The Jensen-Shannon divergence provides a quantitative entropic measure through which genomic DNA can be divided into compositionally distinct domains by a standard recursive segmentation procedure. In this article we show the scaling behaviour observed in domain length distribution and further explore the significance of these domains in the context of gene location, in application to the segmentation of a complete bacterial genome. We also show that this entropic measure has the potential of detecting the horizontally transferred genes in a genome.

Ramaswamy, Ramakrishna; Azad, Rajeev K.

242

Characterization of Transmembrane Segments 3, 4, and 5 of MalF by Mutational Analysis  

Microsoft Academic Search

MalF and MalG are the cytoplasmic membrane components of the binding protein-dependent ATP binding cassette maltose transporter in Escherichia coli. They are thought to form the transport channel and are thus of critical importance for the mechanism of transport. To study the contributions of individual transmembrane segments of MalF, we isolated 27 point mutations in membrane-spanning segments 3, 4, and

ANGELIKA STEINKE; SANDRA GRAU; AMY DAVIDSON; ECKHARD HOFMANN; MICHAEL EHRMANN

2001-01-01

243

Application of Control Volume Analysis to Cerebrospinal Fluid Dynamics  

NASA Astrophysics Data System (ADS)

Hydrocephalus is among the most common birth defects and may not be prevented nor cured. Afflicted individuals face serious issues, which at present are too complicated and not well enough understood to treat via systematic therapies. This talk outlines the framework and application of a control volume methodology to clinical Phase Contrast MRI data. Specifically, integral control volume analysis utilizes a fundamental, fluid dynamics methodology to quantify intracranial dynamics within a precise, direct, and physically meaningful framework. A chronically shunted, hydrocephalic patient in need of a revision procedure was used as an in vivo case study. Magnetic resonance velocity measurements within the patient's aqueduct were obtained in four biomedical state and were analyzed using the methods presented in this dissertation. Pressure force estimates were obtained, showing distinct differences in amplitude, phase, and waveform shape for different intracranial states within the same individual. Thoughts on the physiological and diagnostic research and development implications/opportunities will be presented.

Wei, Timothy; Cohen, Benjamin; Anor, Tomer; Madsen, Joseph

2011-11-01

244

Segmental analysis of the renal tubule in buffer production and net acid formation.  

PubMed

Papillary and surface micropuncture in Munich-Wistar rats was used to assess the role of proximal segments of superficial and juxtamedullary (JM) nephrons, the distal tubule of superficial nephrons, and the terminal collecting duct in acid excretion. The relative role of these segments in ammonium production, bicarbonate reclamation, and net acid formation was assessed under hydropenic conditions and after a chronic acid load. In these two settings the proximal segment of both kinds of nephrons is the major site of ammonium production and bicarbonate reclamation. However, this segment's contribution to net acid formation was only significant during acidosis. On the other hand, segments beyond the distal tubule appear to be the major site of acid formation. In situ pH measurements were lower in these nephron segments and fell even more after the induction of an acidosis. Ammonia appears to enter fluid between the end of the distal tubule and the base of the collecting duct. In vivo pH measurements made near the bend of Henle's loop of JM nephrons were more alkaline than near the end of the proximal tubule of superficial nephrons. It is postulated that this difference in pH allows ammonium to dissociate, permitting the movement of ammonia out of the tubule lumen and into collecting duct fluid where it is protonated and, therefore, reentrapped. This process is enhanced by the ingestion of a chronic acid load. PMID:6837741

Buerkert, J; Martin, D; Trigg, D

1983-04-01

245

Genetic properties of medium (M) and small (S) genomic RNA segments of Seoul hantavirus isolated from Rattus norvegicus and antigenicity analysis of recombinant nucleocapsid protein  

Microsoft Academic Search

A novel isolate of Seoul (SEO) hantaviruses was detected and identified in Rattus norvegicus in Shandong Province, China and designated as JUN5-14. The partial M segment and the coding region of nucleocapsid protein\\u000a (NP) in the S segment of JUN5-14 were PCR-amplified and sequenced. Nucleotide sequence analysis of the partial M segment (300 bp)\\u000a revealed that JUN5-14 isolate was closely related

Zexin Tao; Zhiyu Wang; Shaoxia Song; Hongling Wen; Guijie Ren; Guiting Wang

2007-01-01

246

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

PubMed

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

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

2014-10-01

247

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

248

Analysis of Hantavirus Genetic Diversity in Argentina: S Segment-Derived Phylogeny  

PubMed Central

Nucleotide sequences were determined for the complete S genome segments of the six distinct hantavirus genotypes from Argentina and for two cell culture-isolated Andes virus strains from Chile. Phylogenetic analysis indicates that, although divergent from each other, all Argentinian hantavirus genotypes group together and form a novel phylogenetic clade with the Andes virus. The previously characterized South American hantaviruses Laguna Negra virus and Rio Mamore virus make up another clade that originates from the same ancestral node as the Argentinian/Chilean viruses. Within the clade of Argentinian/Chilean viruses, three subclades can be defined, although the branching order is somewhat obscure. These are made of (i) “Lechiguanas-like” virus genotypes, (ii) Maciel virus and Pergamino virus genotypes, and (iii) strains of the Andes virus. Two hantavirus genotypes from Brazil, Araraquara and Castello dos Sonhos, were found to group with Maciel virus and Andes virus, respectively. The nucleocapsid protein amino acid sequence variability among the members of the Argentinian/Chilean clade does not exceed 5.8%. It is especially low (3.5%) among oryzomyine species-associated virus genotypes, suggesting recent divergence from the common ancestor. Interestingly, the Maciel and Pergamino viruses fit well with the rest of the clade although their hosts are akodontine rodents. Taken together, these data suggest that under conditions in which potential hosts display a high level of genetic diversity and are sympatric, host switching may play a prominent role in establishing hantavirus genetic diversity. However, cospeciation still remains the dominant factor in the evolution of hantaviruses. PMID:11907216

Bohlman, Marlene C.; Morzunov, Sergey P.; Meissner, John; Taylor, Mary Beth; Ishibashi, Kimiko; Rowe, Joan; Levis, Silvana; Enria, Delia; St. Jeor, Stephen C.

2002-01-01

249

Synfuel program analysis. Volume I. Procedures-capabilities  

SciTech Connect

This is the first of the two volumes describing the analytic procedures and resulting capabilities developed by Resource Applications (RA) for examining the economic viability, public costs, and national benefits of alternative synfuel projects and integrated programs. 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 specifiy cases and interpret outputs. It also contains an explicit description (with examples) of the types of results which can be obtained when applied to: 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. In all cases, 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

250

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

PubMed Central

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

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

2014-01-01

251

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

252

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

253

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

254

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

255

Concepts and analysis for precision segmented reflector and feed support structures  

NASA Technical Reports Server (NTRS)

Several issues surrounding the design of a large (20-meter diameter) Precision Segmented Reflector are investigated. The concerns include development of a reflector support truss geometry that will permit deployment into the required doubly-curved shape without significant member strains. For deployable and erectable reflector support trusses, the reduction of structural redundancy was analyzed to achieve reduced weight and complexity for the designs. The stiffness and accuracy of such reduced member trusses, however, were found to be affected to a degree that is unexpected. The Precision Segmented Reflector designs were developed with performance requirements that represent the Reflector application. A novel deployable sunshade concept was developed, and a detailed parametric study of various feed support structural concepts was performed. The results of the detailed study reveal what may be the most desirable feed support structure geometry for Precision Segmented Reflector/Large Deployable Reflector applications.

Miller, Richard K.; Thomson, Mark W.; Hedgepeth, John M.

1990-01-01

256

Motion analysis of knee joint using dynamic volume images  

NASA Astrophysics Data System (ADS)

Acquisition and analysis of three-dimensional movement of knee joint is desired in orthopedic surgery. We have developed two methods to obtain dynamic volume images of knee joint. One is a 2D/3D registration method combining a bi-plane dynamic X-ray fluoroscopy and a static three-dimensional CT, the other is a method using so-called 4D-CT that uses a cone-beam and a wide 2D detector. In this paper, we present two analyses of knee joint movement obtained by these methods: (1) transition of the nearest points between femur and tibia (2) principal component analysis (PCA) of six parameters representing the three dimensional movement of knee. As a preprocessing for the analysis, at first the femur and tibia regions are extracted from volume data at each time frame and then the registration of the tibia between different frames by an affine transformation consisting of rotation and translation are performed. The same transformation is applied femur as well. Using those image data, the movement of femur relative to tibia can be analyzed. Six movement parameters of femur consisting of three translation parameters and three rotation parameters are obtained from those images. In the analysis (1), axis of each bone is first found and then the flexion angle of the knee joint is calculated. For each flexion angle, the minimum distance between femur and tibia and the location giving the minimum distance are found in both lateral condyle and medial condyle. As a result, it was observed that the movement of lateral condyle is larger than medial condyle. In the analysis (2), it was found that the movement of the knee can be represented by the first three principal components with precision of 99.58% and those three components seem to strongly relate to three major movements of femur in the knee bend known in orthopedic surgery.

Haneishi, Hideaki; Kohno, Takahiro; Suzuki, Masahiko; Moriya, Hideshige; Mori, Sin-ichiro; Endo, Masahiro

2006-03-01

257

Analysis of Segmented Reflector Antenna for a Large Millimeter Wave Radio Telescope.  

NASA Astrophysics Data System (ADS)

We have developed a computational tool which serves to characterize the performance of large segmented reflector antennas under different sets of conditions. We have applied this tool to the characterization of a large millimeter telescope. A 50 meter diameter instrument of this type specified to operate to wavelengths as short as 1 mm is being design with an actively controlled main surface consisting of 126 hexagonal segments. To simulate the effect of the necessarily imperfect control system, we generate samples of tilt and piston errors for the segments from which the antenna radiation patterns and aperture efficiencies are calculated. We make a comparison of these results with models of antenna tolerance theory developed by Ruze, which relates the aperture efficiency to the rms phase error. We find that Ruze's formula have a different range of validity when the aperture rms phase error, rather than the rms surface error, is used as a parameter. When appreciable tilt errors are present in large segmented antennas, the aperture rms phase error tends to a constant value, independent of the aperture illumination and of the shape of the segments. We conclude that the antenna rms surface error is a better tracer of the aperture efficiency than is the aperture rms phase error when Ruze's formula is used. We find that this well -known expression stands as a lower limit to the performance of large segmented reflector antennas. We have analyzed the effect that gaps between the segments of the active surface of this antenna as well as the imperfect positioning of the subreflector surface have on the aperture efficiency, antenna gain and radiation pattern of this antenna. We have found that the gaps produce a series of grating lobes distributed in a regular pattern in the far field of this antenna, whose relative position is correlated with the size and shape of the segments. We have found that the large millimeter telescope is very sensitive to axial subreflector positioning errors, requiring that the subreflector actuators be able to maintain is optimum position within a small fraction of a wavelength. With the interest to use a focal plane array in the LMT, we have made a comparative study of the imaging properties of the LMT with that of two aplanatic Cassegrain designs, namely, the Schwarzschild and the Ritchey-Chretien telescope. We found that operating at millimeter wavelengths the three Cassegrain systems have an equivalent performance. This study also revealed the potential benefits of an aplanatic configuration at shorter wavelengths or smaller system focal ratios.

Cortes-Medellin, German

1993-11-01

258

The Segmented Prony method for the analysis of non-stationary time series  

NASA Astrophysics Data System (ADS)

An extension of the classic Prony method for fitting a sum of damped sinusoids to experimental data is proposed. This new method, called the Segmented Prony's Method or SPM, is particularly suited to studying time-varying phenomena. It is based on a division of the observational interval into several short segments, where the signal can be assumed stationary. A model for the data, dependent on a set of parameters, is estimated by means of an efficient algorithm based on well-known recursions for the estimation of the autoregressive coefficients. An application to an X-ray observation of the active galaxy NGC 7314 is discussed.

Barone, P.; Massaro, E.; Polichetti, A.

1989-01-01

259

Automatic partitioning of head CTA for enabling segmentation  

NASA Astrophysics Data System (ADS)

Radiologists perform a CT Angiography procedure to examine vascular structures and associated pathologies such as aneurysms. Volume rendering is used to exploit volumetric capabilities of CT that provides complete interactive 3-D visualization. However, bone forms an occluding structure and must be segmented out. The anatomical complexity of the head creates a major challenge in the segmentation of bone and vessel. An analysis of the head volume reveals varying spatial relationships between vessel and bone that can be separated into three sub-volumes: "proximal", "middle", and "distal". The "proximal" and "distal" sub-volumes contain good spatial separation between bone and vessel (carotid referenced here). Bone and vessel appear contiguous in the "middle" partition that remains the most challenging region for segmentation. The partition algorithm is used to automatically identify these partition locations so that different segmentation methods can be developed for each sub-volume. The partition locations are computed using bone, image entropy, and sinus profiles along with a rule-based method. The algorithm is validated on 21 cases (varying volume sizes, resolution, clinical sites, pathologies) using ground truth identified visually. The algorithm is also computationally efficient, processing a 500+ slice volume in 6 seconds (an impressive 0.01 seconds / slice) that makes it an attractive algorithm for pre-processing large volumes. The partition algorithm is integrated into the segmentation workflow. Fast and simple algorithms are implemented for processing the "proximal" and "distal" partitions. Complex methods are restricted to only the "middle" partition. The partitionenabled segmentation has been successfully tested and results are shown from multiple cases.

Suryanarayanan, Srikanth; Mullick, Rakesh; Mallya, Yogish; Kamath, Vidya; Nagaraj, Nithin

2004-05-01

260

A fully-automatic caudate nucleus segmentation of brain MRI: Application in volumetric analysis of pediatric attention-deficit/hyperactivity disorder  

PubMed Central

Background Accurate automatic segmentation of the caudate nucleus in magnetic resonance images (MRI) of the brain is of great interest in the analysis of developmental disorders. Segmentation methods based on a single atlas or on multiple atlases have been shown to suitably localize caudate structure. However, the atlas prior information may not represent the structure of interest correctly. It may therefore be useful to introduce a more flexible technique for accurate segmentations. Method We present Cau-dateCut: a new fully-automatic method of segmenting the caudate nucleus in MRI. CaudateCut combines an atlas-based segmentation strategy with the Graph Cut energy-minimization framework. We adapt the Graph Cut model to make it suitable for segmenting small, low-contrast structures, such as the caudate nucleus, by defining new energy function data and boundary potentials. In particular, we exploit information concerning the intensity and geometry, and we add supervised energies based on contextual brain structures. Furthermore, we reinforce boundary detection using a new multi-scale edgeness measure. Results We apply the novel CaudateCut method to the segmentation of the caudate nucleus to a new set of 39 pediatric attention-deficit/hyperactivity disorder (ADHD) patients and 40 control children, as well as to a public database of 18 subjects. We evaluate the quality of the segmentation using several volumetric and voxel by voxel measures. Our results show improved performance in terms of segmentation compared to state-of-the-art approaches, obtaining a mean overlap of 80.75%. Moreover, we present a quantitative volumetric analysis of caudate abnormalities in pediatric ADHD, the results of which show strong correlation with expert manual analysis. Conclusion CaudateCut generates segmentation results that are comparable to gold-standard segmentations and which are reliable in the analysis of differentiating neuroanatomical abnormalities between healthy controls and pediatric ADHD. PMID:22141926

2011-01-01

261

Hospital benefit segmentation.  

PubMed

Market segmentation is an important topic to both health care practitioners and researchers. The authors explore the relative importance that health care consumers attach to various benefits available in a major metropolitan area hospital. The purposes of the study are to test, and provide data to illustrate, the efficacy of one approach to hospital benefit segmentation analysis. PMID:10280370

Finn, D W; Lamb, C W

1986-12-01

262

Adaptive neonate brain segmentation.  

PubMed

Babies born prematurely are at increased risk of adverse neurodevelopmental outcomes. Recent advances suggest that measurement of brain volumes can help in defining biomarkers for neurodevelopmental outcome. These techniques rely on an accurate segmentation of the MRI data. However, due to lack of contrast, partial volume (PV) effect, the existence of both hypo- and hyper-intensities and significant natural and pathological anatomical variability, the segmentation of neonatal brain MRI is challenging. We propose a pipeline for image segmentation that uses a novel multi-model Maximum a posteriori Expectation Maximisation (MAP-EM) segmentation algorithm with a prior over both intensities and the tissue proportions, a B0 inhomogeneity correction, and a spatial homogeneity term through the use of a Markov Random Field. This robust and adaptive technique enables the segmentation of images with high anatomical disparity from a normal population. Furthermore, the proposed method implicitly models Partial Volume, mitigating the problem of neonatal white/grey matter intensity inversion. Experiments performed on a clinical cohort show expected statistically significant correlations with gestational age at birth and birthweight. Furthermore, the proposed method obtains statistically significant improvements in Dice scores when compared to the a Maximum Likelihood EM algorithm. PMID:22003722

Cardoso, M Jorge; Melbourne, Andrew; Kendall, Giles S; Modat, Marc; Hagmann, Cornelia F; Robertson, Nicola J; Marlow, Neil; Ourselin, Sebastien

2011-01-01

263

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

264

Lineament analysis of satellite images using a Segment Tracing Algorithm (STA)  

Microsoft Academic Search

Regional fault patterns contribute important information for preliminary exploration for mineralized areas and characterization of geologic structure. Faults may correspond with lineaments appearing on remotely sensed images. In this paper, a new lineament identification method, namely the Segment Tracing Algorithm (STA), is proposed, and its application in mountainous areas of southwestern Japan is discussed. The principle of the STA is

Katsuaki Koike; Shuichi Nagano; Michito Ohmi

1995-01-01

265

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

266

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

267

Road Sign Detection and Recognition using Colour Segmentation, Shape Analysis and Template Matching  

Microsoft Academic Search

The paper presents a system for detection and recognition of road signs with red boundaries and black symbols inside. The detection is invariant to varying lighting conditions and shadows. The algorithm is tested on RGB images taken from camera. These images are converted to HSV colour space. Colour segmentation for red regions is applied on the whole image. All red

RABIA MALIK; JAVAID KHURSHID; SANA NAZIR AHMAD

2007-01-01

268

Influence of Pressure on Chain and Segmental Dynamics in Polyisoprene  

SciTech Connect

We present detailed studies of variation in segmental and chain dynamics of polyisoprene under pressure. Samples with two molecular weights (MW), 2.4 and 25 kg/mol (below and above entanglement), were investigated. Dielectric spectroscopy measurements at isobaric and isothermal conditions exhibit clear differences in temperature and pressure dependencies of chain and segmental relaxation times. Moreover, application of pressure increases time separation between the segmental and normal (chain) modes at the isochronic conditions. This increase can be explained by an effective increase in number of Rouse segments under compression at the same segmental relaxation time. Our analysis also reveals that the thermodynamic scaling of the relaxation times (log vs TV , V is volume) does not work well simultaneously for both processes.

Pawlus, Sebastian [University of Silesia, Uniwersytecka, Katowice, Poland; Sokolov, Alexei P [ORNL; Paluch, Marian [University of Silesia, Uniwersytecka, Katowice, Poland; Mierzwa, Michal [University of Silesia, Uniwersytecka, Katowice, Poland

2010-01-01

269

Vessel Segmentation with Automatic Centerline Extraction Using Tubular Tree Segmentation  

E-print Network

-uniform image intensity along the ves- sel, and the branching and thinning geometry of the vessel tree. We hand need an explicit step for skeletonization of the vessel volume after segmentation. Another bene segmentation is vital to surgery planning and the diagnosis of cardio- vascular disorders

Paris-Sud XI, Université de

270

Value and limitations of segmental analysis of stress thallium myocardial imaging for localization of coronary artery disease  

SciTech Connect

This study was done to determine the value of thallium-201 myocardial scintigraphic imaging (MSI) for identifying disease in the individual coronary arteries. Segmental analysis of rest and stress MSI was performed in 133 patients with ateriographically proved coronary artery disease (CAD). Certain scintigraphic segments were highly specific (97 to 100%) for the three major coronary arteries: anterior wall and septum for the left anterior descending (LAD) coronary artery; the inferior wall for the right coronary artery (RCA); and the proximal lateral wall for the circumflex (LCX) artery. Perfusion defects located in the anterolateral wall in the anterior view were highly specific for proximal disease in the LAD involving the major diagonal branches, but this was not true for septal defects. The apical segments were not specific for any of the three major vessels. Although MSI was abnormal in 89% of these patients with CAD, it was less sensitive for identifying individual vessel disease: 63% for LAD, 50% for RCA, and 21% for LCX disease (narrowings > = 50%). Sensitivity increased with the severity of stenosis, but even for 100% occlusions was only 87% for LAD, 58% for RCA and 38% for LCX. Sensitivity diminished as the number of vessels involved increased: with single-vessel disease, 80% of LAD, 54% of RAC and 33% of LCX lesions were detected, but in patients with triple-vessel disease, only 50% of LAD, 50% of RCA and 16% of LCX lesions were identified. Thus, although segmented analysis of MSI can identify disease in the individual coronary arteries with high specificity, only moderate sensitivity is achieved, reflecting the tendency of MSI to identify only the most severely ischemic area among several that may be present in a heart. Perfusion scintigrams display relative distributions rather than absolute values for myocardial blood flow.

Rigo, P.; Bailey, I.K.; Griffith, L.S.C.; Pitt, B.; Borow, R.D.; Wagner, H.N.; Becker, L.C.

1980-05-01

271

Individual Trabecula Segmentation (ITS)-Based Morphological Analyses and Micro Finite Element Analysis of HR-pQCT Images Discriminate Postmenopausal Fragility Fractures Independent of DXA Measurements  

PubMed Central

Osteoporosis is typically diagnosed by dual energy x-ray absorptiometry (DXA) measurements of areal bone mineral density (aBMD). Emerging technologies, such as high-resolution peripheral quantitative computed tomography (HR-pQCT), may increase the diagnostic accuracy of DXA and enhance our mechanistic understanding of decreased bone strength in osteoporosis. Women with (n=68) and without (n=101) a history of postmenopausal fragility fracture had aBMD measured by DXA, trabecular plate and rod microarchitecture measured by HR-pQCT image-based individual trabeculae segmentation (ITS) analysis, and whole bone and trabecular bone stiffness by micro finite element analysis (?FEA) of HR-pQCT images at the radius and tibia. DXA T-scores were similar in women with and without fractures at the spine, hip and 1/3 radius, but lower in fracture subjects at the ultradistal radius. Trabecular microarchitecture of fracture subjects was characterized by preferential reductions in trabecular plate bone volume, number, and connectivity over rod trabecular parameters, loss of axially aligned trabeculae, and a more rod-like trabecular network. In addition, decreased thickness and size of trabecular plates were observed at the tibia. The differences between groups were greater at the radius than the tibia for plate number, rod bone volume fraction and number and plate-rod and rod-rod junction densities. Most differences between groups remained after adjustment for T-score by DXA. At a fixed bone volume fraction, trabecular plate volume, number and connectivity were directly associated with bone stiffness. In contrast, rod volume, number and connectivity were inversely associated with bone stiffness. In summary, HR-pQCT-based ITS and ?FEA measurements discriminate fracture status in postmenopausal women independent of DXA measurements. Moreover, these results suggest that preferential loss of plate-like trabeculae contribute to lower trabecular bone and whole bone stiffness in women with fractures. We conclude that HR-pQCT-based ITS and ?FEA measurements increase our understanding of the microstructural pathogenesis of fragility fracture in postmenopausal women. PMID:22072446

Liu, X. Sherry; Stein, Emily M.; Zhou, Bin; Zhang, Chiyuan A.; Nickolas, Thomas L.; Cohen, Adi; Thomas, Valerie; McMahon, Donald J.; Cosman, Felicia; Nieves, Jeri; Shane, Elizabeth; Guo, X. Edward

2011-01-01

272

Individual trabecula segmentation (ITS)-based morphological analyses and microfinite element analysis of HR-pQCT images discriminate postmenopausal fragility fractures independent of DXA measurements.  

PubMed

Osteoporosis is typically diagnosed by dual-energy X-ray absorptiometry (DXA) measurements of areal bone mineral density (aBMD). Emerging technologies, such as high-resolution peripheral quantitative computed tomography (HR-pQCT), may increase the diagnostic accuracy of DXA and enhance our mechanistic understanding of decreased bone strength in osteoporosis. Women with (n = 68) and without (n = 101) a history of postmenopausal fragility fracture had aBMD measured by DXA, trabecular plate and rod microarchitecture measured by HR-pQCT image-based individual trabecula segmentation (ITS) analysis, and whole bone and trabecular bone stiffness by microfinite element analysis (µFEA) of HR-pQCT images at the radius and tibia. DXA T-scores were similar in women with and without fractures at the spine, hip, and 1/3 radius, but lower in fracture subjects at the ultradistal radius. Trabecular microarchitecture of fracture subjects was characterized by preferential reductions in trabecular plate bone volume, number, and connectivity over rod trabecular parameters, loss of axially aligned trabeculae, and a more rod-like trabecular network. In addition, decreased thickness and size of trabecular plates were observed at the tibia. The differences between groups were greater at the radius than the tibia for plate number, rod bone volume fraction and number, and plate-rod and rod-rod junction densities. Most differences between groups remained after adjustment for T-score by DXA. At a fixed bone volume fraction, trabecular plate volume, number, and connectivity were directly associated with bone stiffness. In contrast, rod volume, number, and connectivity were inversely associated with bone stiffness. In summary, HR-pQCT-based ITS and µFEA measurements discriminate fracture status in postmenopausal women independent of DXA measurements. Moreover, these results suggest that preferential loss of plate-like trabeculae contribute to lower trabecular bone and whole bone stiffness in women with fractures. We conclude that HR-pQCT-based ITS and µFEA measurements increase our understanding of the microstructural pathogenesis of fragility fracture in postmenopausal women. PMID:22072446

Liu, X Sherry; Stein, Emily M; Zhou, Bin; Zhang, Chiyuan A; Nickolas, Thomas L; Cohen, Adi; Thomas, Valerie; McMahon, Donald J; Cosman, Felicia; Nieves, Jeri; Shane, Elizabeth; Guo, X Edward

2012-02-01

273

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

274

A spatiotemporal-based scheme for efficient registration-based segmentation of thoracic 4-D MRI.  

PubMed

Dynamic three-dimensional (3-D) (four-dimensional, 4-D) magnetic resonance (MR) imaging is gaining importance in the study of pulmonary motion for respiratory diseases and pulmonary tumor motion for radiotherapy. To perform quantitative analysis using 4-D MR images, segmentation of anatomical structures such as the lung and pulmonary tumor is required. Manual segmentation of entire thoracic 4-D MRI data that typically contains many 3-D volumes acquired over several breathing cycles is extremely tedious, time consuming, and suffers high user variability. This requires the development of new automated segmentation schemes for 4-D MRI data segmentation. Registration-based segmentation technique that uses automatic registration methods for segmentation has been shown to be an accurate method to segment structures for 4-D data series. However, directly applying registration-based segmentation to segment 4-D MRI series lacks efficiency. Here we propose an automated 4-D registration-based segmentation scheme that is based on spatiotemporal information for the segmentation of thoracic 4-D MR lung images. The proposed scheme saved up to 95% of computation amount while achieving comparable accurate segmentations compared to directly applying registration-based segmentation to 4-D dataset. The scheme facilitates rapid 3-D/4-D visualization of the lung and tumor motion and potentially the tracking of tumor during radiation delivery. PMID:24058039

Yang, Y; Van Reeth, E; Poh, C L; Tan, C H; Tham, I W K

2014-05-01

275

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

276

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

277

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

278

Flood - Volume Analysis and Efficiency of The Dam Spillways  

NASA Astrophysics Data System (ADS)

Past experience and statistical data show that extreme floods constitute an important risk for the hydrological safety of dams. Overtopping represents more than 40% of dam failures in the world, and has been also cause of many other accidents. For this reason, the problem of selecting the appropriate design flood is a constant concern to dam engineering. This concern is even more important for those dams that are also explicitly committed to flood control target. In the present talk we investigate the hydrological safety of dams checking the efficiency of the dam spillways. A new statistical procedure based on the flood-volume analysis is developed. An application to Ceppo Morelli dam, on Anza river basin, in Piedmont, Italy, is given.

Canossi, M.; de Michele, C.; Petaccia, A.; Rosso, R.

279

Segmental neurofibromatosis  

PubMed Central

Segmental neurofibromatosis is a rare disorder, characterized by neurofibromas or caf?-au-lait macules limited to one region of the body. Its occurrence on the face is extremely rare and only few cases of segmental neurofibromatosis over the face have been described so far. We present a case of segmental neurofibromatosis involving the buccal mucosa, tongue, cheek, ear, and neck on the right side of the face.

Galhotra, Virat; Sheikh, Soheyl; Jindal, Sanjeev; Singla, Anshu

2014-01-01

280

Congenital Aortic Disease: 4D Magnetic Resonance Segmentation and Quantitative Analysis  

PubMed Central

Automated and accurate segmentation of the aorta in 4D (3D+time) cardiovascular magnetic resonance (MR) image data is important for early detection of congenital aortic disease leading to aortic aneurysms and dissections. A computer-aided diagnosis method is reported that allows one to objectively identify subjects with connective tissue disorders from sixteen-phase 4D aortic MR images. Starting with a step of multi-view image registration, our automated segmentation method combines level-set and optimal surface segmentation algorithms in a single optimization process so that the final aortic surfaces in all 16 cardiac phases are determined. The resulting aortic lumen surface is registered with an aortic model followed by calculation of modal indices of aortic shape and motion. The modal indices reflect the differences of any individual aortic shape and motion from an average aortic behavior. A Support Vector Machine (SVM) classifier is used for the discrimination between normal and connective tissue disorder subjects. 4D MR image data sets acquired from 104 normal and connective tissue disorder MR datasets were used for development and performance evaluation of our method. The automated 4D segmentation resulted in accurate aortic surfaces in all 16 cardiac phases, covering the aorta from the aortic annulus to the diaphragm, yielding subvoxel accuracy with signed surface positioning errors of ?0.07 ± 1.16 voxel (?0.10 ± 2.05 mm). The computer aided diagnosis method distinguished between normal and connective tissue disorder subjects with a classification correctness of 90.4%. PMID:19303351

Zhao, Fei; Zhang, Honghai; Wahle, Andreas; Thomas, Matthew T.; Stolpen, Alan H.; Scholz, Thomas D.; Sonka, Milan

2009-01-01

281

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

282

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

Microsoft Academic Search

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

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

2011-01-01

283

Analysis of multiscale texture segmentation using wavelet-domain hidden Markov models  

Microsoft Academic Search

Wavelet-domain hidden Markov tree (HMT) models are powerful tools for modeling the statistical properties of wavelet transforms. By characterizing the joint statistics of the wavelet coefficients, HMTs efficiently capture the characteristics of a large class of real-world signals and images. In this paper, we apply this multiscale statistical description to the texture segmentation problem. We also show how the Kullback-Leibler

Hyeokho Choi; Brent Hendricks; R. Baraniuk

1999-01-01

284

Intravenous Electron-Beam Computed Tomographic Coronary Angiography for Segmental Analysis of Coronary Artery Stenoses  

Microsoft Academic Search

Objectives. We sought to identify and localize significant coronary stenoses on a segmental basis by electron-beam computed tomography (EBCT) and intravenous administration of a contrast agent.Background. The clinical applicability and limitations of intravenous EBCT coronary angiography have not been defined.Methods. EBCT was performed within 24 h of selective coronary angiography (SCA) in 28 patients (19 men and 9 women, mean

Axel Schmermund; Benno J Rensing; Patrick F Sheedy; Malcolm R Bell; John A Rumberger

1998-01-01

285

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

PubMed

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

Qiu, J; Li, F-F

2014-12-01

286

A geometric analysis of mastectomy incisions: Optimizing intraoperative breast volume  

PubMed Central

INTRODUCTION: The advent of acellular dermis-based tissue expander breast reconstruction has placed an increased emphasis on optimizing intraoperative volume. Because skin preservation is a critical determinant of intraoperative volume expansion, a mathematical model was developed to capture the influence of incision dimension on subsequent tissue expander volumes. METHODS: A mathematical equation was developed to calculate breast volume via integration of a geometrically modelled breast cross-section. The equation calculates volume changes associated with excised skin during the mastectomy incision by reducing the arc length of the cross-section. The degree of volume loss is subsequently calculated based on excision dimensions ranging from 35 mm to 60 mm. RESULTS: A quadratic relationship between breast volume and the vertical dimension of the mastectomy incision exists, such that incrementally larger incisions lead to a disproportionally greater amount of volume loss. The vertical dimension of the mastectomy incision – more so than the horizontal dimension – is of critical importance to maintain breast volume. Moreover, the predicted volume loss is more profound in smaller breasts and primarily occurs in areas that affect breast projection on ptosis. CONCLUSIONS: The present study is the first to model the relationship between the vertical dimensions of the mastectomy incision and subsequent volume loss. These geometric principles will aid in optimizing intra-operative volume expansion during expander-based breast reconstruction. PMID:22654531

Chopp, David; Rawlani, Vinay; Ellis, Marco; Johnson, Sarah A; Buck, Donald W; Khan, Seema; Bethke, Kevin; Hansen, Nora; Kim, John YS

2011-01-01

287

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

288

Genomic sequence analysis of the MHC class I G/F segment in common marmoset (Callithrix jacchus).  

PubMed

The common marmoset (Callithrix jacchus) is a New World monkey that is used frequently as a model for various human diseases. However, detailed knowledge about the MHC is still lacking. In this study, we sequenced and annotated a total of 854 kb of the common marmoset MHC region that corresponds to the HLA-A/G/F segment (Caja-G/F) between the Caja-G1 and RNF39 genes. The sequenced region contains 19 MHC class I genes, of which 14 are of the MHC-G (Caja-G) type, and 5 are of the MHC-F (Caja-F) type. Six putatively functional Caja-G and Caja-F genes (Caja-G1, Caja-G3, Caja-G7, Caja-G12, Caja-G13, and Caja-F4), 13 pseudogenes related either to Caja-G or Caja-F, three non-MHC genes (ZNRD1, PPPIR11, and RNF39), two miscRNA genes (ZNRD1-AS1 and HCG8), and one non-MHC pseudogene (ETF1P1) were identified. Phylogenetic analysis suggests segmental duplications of units consisting of basically five (four Caja-G and one Caja-F) MHC class I genes, with subsequent expansion/deletion of genes. A similar genomic organization of the Caja-G/F segment has not been observed in catarrhine primates, indicating that this genomic segment was formed in New World monkeys after the split of New World and Old World monkeys. PMID:24600031

Kono, Azumi; Brameier, Markus; Roos, Christian; Suzuki, Shingo; Shigenari, Atsuko; Kametani, Yoshie; Kitaura, Kazutaka; Matsutani, Takaji; Suzuki, Ryuji; Inoko, Hidetoshi; Walter, Lutz; Shiina, Takashi

2014-04-01

289

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

290

Comparative analysis of operational forecasts versus actual weather conditions in airline flight planning, volume 3  

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 3 of the four major tasks included in the study. Task 3 compares flight plans developed on the Suitland forecast with actual data observed by the aircraft (and averaged over 10 degree segments). The results show that the average difference between the forecast and observed wind speed is 9 kts. without considering direction, and the average difference in the component of the forecast wind parallel to the direction of the observed wind is 13 kts. - both indicating that the Suitland forecast underestimates the wind speeds. The Root Mean Square (RMS) vector error is 30.1 kts. The average absolute difference in direction between the forecast and observed wind is 26 degrees and the temperature difference is 3 degree Centigrade. These results indicate that the forecast model as well as the verifying analysis used to develop comparison flight plans in Tasks 1 and 2 is a limiting factor and that the average potential fuel savings or penalty are up to 3.6 percent depending on the direction of flight.

Keitz, J. F.

1982-01-01

291

National Evaluation of Family Support Programs. Final Report Volume A: The Meta-Analysis.  

ERIC Educational Resources Information Center

This volume is part of the final report of the National Evaluation of Family Support Programs and details findings from a meta-analysis of extant research on programs providing family support services. Chapter A1 of this volume provides a rationale for using meta-analysis. Chapter A2 describes the steps of preparation for the meta-analysis.…

Layzer, Jean I.; Goodson, Barbara D.; Bernstein, Lawrence; Price, Cristofer

292

Multimodal retinal vessel segmentation from spectral-domain optical coherence tomography and fundus photography.  

PubMed

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

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

2012-10-01

293

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

294

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

295

Risk for Adjacent Segment and Same Segment Reoperation After Surgery for Lumbar Stenosis: A subgroup analysis of the Spine Patient Outcomes Research Trial (SPORT)  

PubMed Central

Study Design Subgroup analysis of prospective, randomized database. Objective The purpose of this study was to compare surgical or patient characteristics, such as fusion, instrumentation, or obesity, to identify whether these factors were associated with increased risk of reoperation for spinal stenosis. This prognostic information would be valuable to patients, healthcare professionals, and society as strategies to reduce reoperation, such as motion preservation, are developed. Summary of Background Data Reoperation due to recurrence of index level pathology or adjacent segment disease is a common clinical problem. Despite multiple studies on the incidence of reoperation, there have been few comparative studies establishing risk factors of reoperation after spinal stenosis surgery. The hypothesis of this subgroup analysis was that lumbar fusion or particular patient characteristics, such as obesity, would render patients with lumbar stenosis more susceptible to reoperation at the index or adjacent levels. Methods The study population combined the randomized and observational cohorts enrolled in SPORT for treatment of spinal stenosis. The surgically treated patients were stratified according to those who had reoperation (n=54) or no-reoperation (n= 359). Outcome measures were assessed at baseline, 1 year, 2 years, 3 years, and 4 years. The difference in improvement between those who had reoperation and those who did not was determined at each follow-period. Results Of the 413 patients who underwent surgical treatment for spinal stenosis, 54 patients had a reoperation within four years. At baseline, there were no significant differences in demographic characteristics or clinical outcome scores between reoperation and non-reoperation groups. Furthermore, between groups there were no differences in the severity of symptoms, obesity, physical examination signs, levels of stenosis, location of stenosis, stenosis severity, levels of fusion, levels of laminectomy, levels decompressed, operation time, intraoperative or postoperative complications. There was an increased percentage of patients with duration of symptoms greater than 12 months in the reoperation group (56% reoperation vs 36% no-reoperation, p<0.008). At final follow-up, there was significantly less improvement in the outcome of the reoperation group in SF36 PF (14.4 vs 22.6, p < 0.05), ODI (?12.4 vs. ?21.1, p < 0.01), and Sciatica Bothersomeness Index (?5 vs ?8.1, p < 0.006). Conclusion Lumbar fusion and instrumentation were not associated with increased rate of reoperation at index or adjacent levels compared to nonfusion techniques. The only specific risk factor for reoperation after treatment of spinal stenosis was duration of pretreatment symptoms > 12 months. The overall incidence of reoperations for spinal stenosis surgery was 13% and reoperations were equally distributed between index and adjacent lumbar levels. Reoperation may be related to the natural history of spinal degenerative disease. PMID:23154835

Radcliff, Kris; Curry, Patrick; Hilibrand, Alan; Kepler, Chris; Lurie, Jon; Zhao, Wenyan; Albert, Todd; Weinstein, James

2013-01-01

296

Mass segmentation of dense breasts on digitized mammograms: analysis of a probability-based function  

NASA Astrophysics Data System (ADS)

In this study, a segmentation algorithm based on the steepest changes of a probabilistic cost function was tested on non-processed and pre-processed dense breast images in an attempt to determine the efficacy of pre-processing for dense breast masses. Also, the inter-observer variability between expert radiologists was studied. Background trend correction was used as the pre-processing method. The algorithm, based on searching the steepest changes on a probabilistic cost function, was tested on 107 cancerous masses and 98 benign masses with density ratings of 3 or 4 according to the American College of Radiology's density rating scale. The computer-segmented results were validated using the following statistics: overlap, accuracy, sensitivity, specificity, Dice similarity index, and kappa. The mean accuracy statistic value ranged from 0.71 to 0.84 for cancer cases and 0.81 to 0.86 for benign cases. For nearly all statistics there were statistically significant differences between the expert radiologists.

Kinnard, Lisa M.; Lo, Shih-Chung B.; Duckett, Eva; Makariou, Erini; Osicka, Teresa; Freedman, Matthew T.; Chouikha, Mohamed F.

2005-04-01

297

Knowledge-based 3D segmentation of the brain in MR images for quantitative multiple sclerosis lesion tracking  

NASA Astrophysics Data System (ADS)

Brain segmentation in magnetic resonance (MR) images is an important step in quantitative analysis applications, including the characterization of multiple sclerosis (MS) lesions over time. Our approach is based on a priori knowledge of the intensity and three-dimensional (3D) spatial relationships of structures in MR images of the head. Optimal thresholding and connected-components analysis are used to generate a starting point for segmentation. A 3D radial search is then performed to locate probable locations of the intra-cranial cavity (ICC). Missing portions of the ICC surface are interpolated in order to exclude connected structures. Partial volume effects and inter-slice intensity variations in the image are accounted for automatically. Several studies were conducted to validate the segmentation. Accuracy was tested by calculating the segmented volume and comparing to known volumes of a standard MR phantom. Reliability was tested by comparing calculated volumes of individual segmentation results from multiple images of the same subject. The segmentation results were also compared to manual tracings. The average error in volume measurements for the phantom was 1.5% and the average coefficient of variation of brain volume measurements of the same subject was 1.2%. Since the new algorithm requires minimal user interaction, variability introduced by manual tracing and interactive threshold or region selection was eliminated. Overall, the new algorithm was shown to produce a more accurate and reliable brain segmentation than existing manual and semi-automated techniques.

Fisher, Elizabeth; Cothren, Robert M., Jr.; Tkach, Jean A.; Masaryk, Thomas J.; Cornhill, J. Fredrick

1997-04-01

298

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

299

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

300

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] [Nevada Univ., Las Vegas, NV (United States). Transportation Research Center

1991-05-31

301

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

302

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

303

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

304

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

Microsoft Academic Search

Ankle fractures are one of the most common lower limb traumas. Several studies reported short- and long-term post-operative results, mainly determined by radiographic and subjective functional evaluations. Three-dimensional gait analysis with a multi-segment foot model was used in the current study to quantify the inter-segment foot motions in 18 patients 1 year after surgically treated ankle fractures. Data were compared

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

2010-01-01

305

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

306

Quantitative trait locus analysis of leaf dissection in tomato using Lycopersicon pennellii segmental introgression lines.  

PubMed Central

Leaves are one of the most conspicuous and important organs of all seed plants. A fundamental source of morphological diversity in leaves is the degree to which the leaf is dissected by lobes and leaflets. We used publicly available segmental introgression lines to describe the quantitative trait loci (QTL) controlling the difference in leaf dissection seen between two tomato species, Lycopersicon esculentum and L. pennellii. We define eight morphological characteristics that comprise the mature tomato leaf and describe loci that affect each of these characters. We found 30 QTL that contribute one or more of these characters. Of these 30 QTL, 22 primarily affect leaf dissection and 8 primarily affect leaf size. On the basis of which characters are affected, four classes of loci emerge that affect leaf dissection. The majority of the QTL produce phenotypes intermediate to the two parent lines, while 5 QTL result in transgression with drastically increased dissection relative to both parent lines. PMID:14668401

Holtan, Hans E E; Hake, Sarah

2003-01-01

307

Analysis of Photoreceptor Rod Outer Segment Phagocytosis by RPE Cells In Situ  

PubMed Central

Counting rhodopsin-positive phagosomes residing in the retinal pigment epithelium (RPE) in the eye at different times of day allows a quantitative assessment of engulfment and digestion phases of diurnal RPE phagocytosis, which efficiently clears shed photoreceptor outer segment fragments (POS) from the neural retina. Comparing such activities among age- and background-matched experimental wild-type and mutant mice or rats serves to identify roles for specific proteins in the phagocytic process. Here, we describe experimental procedures for mouse eye harvest, embedding, sectioning, immunofluorescence labeling of rod POS phagosomes in RPE cells in sagittal eye sections, imaging of POS phagosomes in the RPE by laser scanning confocal microscopy, and POS quantification. PMID:23150373

Sethna, Saumil; Finnemann, Silvia C.

2013-01-01

308

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

309

Estimation of thigh muscle cross-sectional area by single- and multifrequency segmental bioelectrical impedance analysis in the elderly.  

PubMed

Bioelectrical impedance analysis (BIA) has been used to estimate skeletal muscle mass, but its application in the elderly is not optimal. The accuracy of BIA may be influenced by the expansion of extracellular water (ECW) relative to muscle mass with aging. Multifrequency BIA (MFBIA) can evaluate the distribution between ECW and intracellular water (ICW), and thus may be superior to single-frequency BIA (SFBIA) to estimate muscle mass in the elderly. A total of 58 elderly participants aged 65-85 years were recruited. Muscle cross-sectional area (CSA) was obtained from computed tomography scans at the mid-thigh. Segmental SFBIA and MFBIA were measured for the upper legs. An index of the ratio of ECW and ICW was calculated using MFBIA. The correlation between muscle CSA and SFBIA was moderate (r = 0.68), but strong between muscle CSA and MFBIA (r = 0.85). ECW/ICW index was significantly and positively correlated with age (P < 0.001). SFBIA tends to significantly overestimate muscle CSA in subjects who had relative expansion of ECW in the thigh segment (P < 0.001). This trend was not observed for MFBIA (P = 0.42). Relative expansion of ECW was observed in older participants. The relative expansion of ECW affects the validity of traditional SFBIA, which is lowered when estimating muscle CSA in the elderly. By contrast, MFBIA was not affected by water distribution in thigh segments, thus rendering the validity of MFBIA for estimating thigh muscle CSA higher than SFBIA in the elderly. PMID:24114698

Yamada, Yosuke; Ikenaga, Masahiro; Takeda, Noriko; Morimura, Kazuhiro; Miyoshi, Nobuyuki; Kiyonaga, Akira; Kimura, Misaka; Higaki, Yasuki; Tanaka, Hiroaki

2014-01-15

310

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

E-print Network

events, weather events, other energy market prices' influences and macroeconomic determinants (Alberola1 Carbon Prices during the EU ETS Phase II: Dynamics and Volume Analysis Julien Chevallier1, and details the carbon price dynamics during Phase II (2008-2012), along with an analysis of traded volumes

Boyer, Edmond

311

Engineering Analysis and Evaluation of the Centralia Mine Fire. Volume 2.  

National Technical Information Service (NTIS)

Provided in volume 2 is an analysis of the mine fire, which defines fire conditions, identifies ventilation patterns, and determines the progression of the fire. Options to control and/or extinguish the fire are examined, based on the analysis.

1983-01-01

312

Engineering analysis and evaluation of the Centralia mine fire. Volume 2  

SciTech Connect

Provided in volume 2 is an analysis of the mine fire, which defines fire conditions, identifies ventilation patterns, and determines the progression of the fire. Options to control and/or extinguish the fire are examined, based on the analysis.

Not Available

1983-07-01

313

Microstructural analysis of pineal volume using trueFISP imaging  

PubMed Central

AIM: To determine the spectrum of pineal microstructures (solid/cystic parts) in a large clinical population using a high-resolution 3D-T2-weighted sequence. METHODS: A total of 347 patients enrolled for cranial magnetic resonance imaging were randomly included in this study. Written informed consent was obtained from all patients. The exclusion criteria were artifacts or mass lesions prohibiting evaluation of the pineal gland in any of the sequences. True-FISP-3D-imaging (1.5-T, isotropic voxel 0.9 mm) was performed in 347 adults (55.4 ± 18.1 years). Pineal gland volume (PGV), cystic volume, and parenchyma volume (cysts excluded) were measured manually. RESULTS: Overall, 40.3% of pineal glands were cystic. The median PGV was 54.6 mm3 (78.33 ± 89.0 mm3), the median cystic volume was 5.4 mm3 (15.8 ± 37.2 mm3), and the median parenchyma volume was 53.6 mm3 (71.9 ± 66.7 mm3). In cystic glands, the standard deviation of the PGV was substantially higher than in solid glands (98% vs 58% of the mean). PGV declined with age (r = -0.130, P = 0.016). CONCLUSION: The high interindividual volume variation is mainly related to cysts. Pineal parenchyma volume decreased slightly with age, whereas gender-related effects appear to be negligible. PMID:23671752

Bumb, Jan M; Brockmann, Marc A; Groden, Christoph; Nolte, Ingo

2013-01-01

314

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

SciTech Connect

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

Michael Pernice

2009-11-01

315

Design and analysis of district heating systems. Volume 1. Executive summary. Final report  

SciTech Connect

This report summarizes the methodology for assessment of district heating technical and economic feasibility, and the results of site-specific studies performed for the cities of Lansing, Michigan; Providence, Rhode Island; and Springfield, Massachusetts. Requirements for research and development in district heating are also identified. This report is volume 1 of a 4 volume research project entitled Design and Analysis of District Heating Systems. Volume 2 presents the results of a site-specific study for Lansing, Michigan; volume 3 presents the site-specific results for Providence, Rhode Island, and volume 4 presents the site-specific results for Springfield, Massachusetts.

Oliker, I.; Buffa, W.; Silaghy, F.

1985-02-01

316

DESCRIPTIVE ANALYSIS OF PITCH VOLUME IN SOUTHEASTERN CONFERENCE BASEBALL PITCHERS  

PubMed Central

Background: Representative data on typical pitch volume for collegiate pitchers functioning in their specific roles is sparse and is needed for training specificity. Objective: To report pitch volumes in Division I collegiate pitchers. The authors hypothesize that pitcher role will result in different pitch volumes. Methods: Pitchers from twelve Division I collegiate baseball teams pitch volume during the 2009 baseball season was retrospectively reviewed through each team's website. The number of pitches and innings pitched for each pitcher were recorded. Pitchers were categorized based on their role as “Starter-only” (n=15), “Reliever-only” (n=76), or “Combined Starter/Reliever” (n=94) and compared using ANOVA. Results: “Starter-only” pitchers threw the most pitches (97±10) and pitched the most innings (6.0±1.0) per appearance (p=<.001). “Combined Starter/Reliever” functioning as a starter threw significantly more pitches (68±19) and pitched more innings (4.0±1.3) per appearance compared to “Combined Starter/Reliever” functioning as a reliever and “Reliever-only” pitchers (p=<.001). The cumulative volume during a 13 week regular season revealed that “Starter-only” pitchers threw significantly more total pitches (1204±387) compared to “Combined Starter/Reliever” pitchers (613±182) who threw significantly more than “Reliever-only” pitchers (254±77) (P<.001). Discussion: Pitcher's specific roles and representative volumes should be used to design training and rehabilitation programs. Comparison of this data to reported adolescent pitch volumes reveal that adolescent pitch volume per appearance approaches collegiate levels. Conclusions: Collegiate pitcher roles dictate their throwing volume. Starter-only pitchers (8%) throw the greatest cumulative number of pitches and should be trained differently than the majority of college pitchers (92%) who function primarily as a reliever or in combination starter/reliever roles that on average only requires approximately 40 pitches per appearance. PMID:21655377

Love, Shawn; Aytar, Aydan; Bush, Heather

2010-01-01

317

SEGMENTATION OF MITOCHONDRIA IN ELECTRON MICROSCOPY IMAGES USING ALGEBRAIC CURVES  

PubMed Central

High-resolution microscopy techniques have been used to generate large volumes of data with enough details for understanding the complex structure of the nervous system. However, automatic techniques are required to segment cells and intracellular structures in these multi-terabyte datasets and make anatomical analysis possible on a large scale. We propose a fully automated method that exploits both shape information and regional statistics to segment irregularly shaped intracellular structures such as mitochondria in electron microscopy (EM) images. The main idea is to use algebraic curves to extract shape features together with texture features from image patches. Then, these powerful features are used to learn a random forest classifier, which can predict mitochondria locations precisely. Finally, the algebraic curves together with regional information are used to segment the mitochondria at the predicted locations. We demonstrate that our method outperforms the state-of-the-art algorithms in segmentation of mitochondria in EM images. PMID:25132915

Seyedhosseini, Mojtaba; Ellisman, Mark H.; Tasdizen, Tolga

2014-01-01

318

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

319

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

320

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

EPA Science Inventory

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

321

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

322

A combined machine-learning and graph-based framework for the segmentation of retinal surfaces in SD-OCT volumes  

PubMed Central

Optical coherence tomography is routinely used clinically for the detection and management of ocular diseases as well as in research where the studies may involve animals. This routine use requires that the developed automated segmentation methods not only be accurate and reliable, but also be adaptable to meet new requirements. We have previously proposed the use of a graph-theoretic approach for the automated 3-D segmentation of multiple retinal surfaces in volumetric human SD-OCT scans. The method ensures the global optimality of the set of surfaces with respect to a cost function. Cost functions have thus far been typically designed by hand by domain experts. This difficult and time-consuming task significantly impacts the adaptability of these methods to new models. Here, we describe a framework for the automated machine-learning based design of the cost function utilized by this graph-theoretic method. The impact of the learned components on the final segmentation accuracy are statistically assessed in order to tailor the method to specific applications. This adaptability is demonstrated by utilizing the method to segment seven, ten and five retinal surfaces from SD-OCT scans obtained from humans, mice and canines, respectively. The overall unsigned border position errors observed when using the recommended configuration of the graph-theoretic method was 6.45 ± 1.87 ?m, 3.35 ± 0.62 ?m and 9.75 ± 3.18 ?m for the human, mouse and canine set of images, respectively. PMID:24409375

Antony, Bhavna J.; Abramoff, Michael D.; Harper, Matthew M.; Jeong, Woojin; Sohn, Elliott H.; Kwon, Young H.; Kardon, Randy; Garvin, Mona K.

2013-01-01

323

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

324

Interactive algorithms for the segmentation and quantitation of 3-D MRI brain scans.  

PubMed

Interactive algorithms are an attractive approach to the accurate segmentation of 3D brain scans as they potentially improve the reliability of fully automated segmentation while avoiding the labour intensiveness and inaccuracies of manual segmentation. We present a 3D image analysis package (MIDAS) with a novel architecture enabling highly interactive segmentation algorithms to be implemented as add on modules. Interactive methods based on intensity thresholding, region growing and the constrained application of morphological operators are also presented. The methods involve the application of constraints and freedoms on the algorithms coupled with real time visualisation of the effect. This methodology has been applied to the segmentation, visualisation and measurement of the whole brain and a small irregular neuroanatomical structure, the hippocampus. We demonstrate reproducible and anatomically accurate segmentations of these structures. The efficacy of one method in measuring volume loss (atrophy) of the hippocampus in Alzheimer's disease is shown and is compared to conventional methods. PMID:9113464

Freeborough, P A; Fox, N C; Kitney, R I

1997-05-01

325

Exploratory trend and pattern analysis of 1981 through 1983 Licensee Event Report data. Appendices. Volume 2  

SciTech Connect

This volume contains appendixes supporting Volume 1, ''Exploratory Trends and Patterns Analysis of 1981 through 1983 Licensee Event Report Data.'' Together, Volumes 1 and 2 document research performed for the United States Nuclear Regulatory Commission's Office for Analysis and Evaluation of Operational Data (AEOD) as a part of its Trends and Patterns Analysis of Operational Data Program. Volume 1 contains the main findings of this study and a discussion of the results and how they were obtained. The primary purpose of this volume is to present tables of data that support those findings. In addition, there is an appendix with a discussion on variations in LER reporting among plants. The last appendix, provided by AEOD, contains a memo showing AEOD's response to the major issues raised as a result of this analysis.

Hester, O.V.; Groh, M.R.; Farmer, F.G.

1986-10-01

326

Comparative Study of Adaptive Segmentation Techniques for Gesture Analysis in Unconstrained Environments  

Microsoft Academic Search

This paper discusses the importance of providing non- invasive techniques in the analysis of the complex movements performed by musicians and athletes. Current gesture analysis systems are insufficient and do not succeed in providing quality performance measurements without imposing strict environmental and operational constraints on individuals. Computer vision offers the means with which such techniques can be made possible without

Martin Côté; Pierre Payeur; Gilles Comeau

2006-01-01

327

Segmented combustor  

NASA Technical Reports Server (NTRS)

A combustor liner segment includes a panel having four sidewalls forming a rectangular outer perimeter. A plurality of integral supporting lugs are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls. A plurality of integral bosses are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls, with the bosses being shorter than the lugs. In one embodiment, the lugs extend through supporting holes in an annular frame for mounting the liner segments thereto, with the bosses abutting the frame for maintaining a predetermined spacing therefrom.

Halila, Ely E. (Inventor)

1994-01-01

328

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

329

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

330

Segmenting the online consumer market  

Microsoft Academic Search

Purpose – The internet has become mainstream in everyday communications and transactions. This research aims to provide a segmentation analysis for the online market based on the various uses of the internet. Design\\/methodology\\/approach – A review of the online consumer segmentation literature is first conducted. Survey method and cluster analysis techniques are used in the empirical study. A sample of

Muhammad Aljukhadar; Sylvain Senecal

2011-01-01

331

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

332

Segmentation, Registration, and Deformation Analysis of 3D MR Images of Mice  

E-print Network

for Sick Children, Toronto, ON, M5G 1X8, Canada 2 Faculty of Pharmacy, University of Toronto, Toronto, ON) microscopy. In our current work we apply a number of computational image analysis tech- niques in an effort

Hamarneh, Ghassan

333

Partial volume correction and image analysis methods for intersubject comparison of FDG-PET studies  

NASA Astrophysics Data System (ADS)

Partial volume effect is an artifact mainly due to the limited imaging sensor resolution. It creates bias in the measured activity in small structures and around tissue boundaries. In brain FDG-PET studies, especially for Alzheimer's disease study where there is serious gray matter atrophy, accurate estimate of cerebral metabolic rate of glucose is even more problematic due to large amount of partial volume effect. In this dissertation, we developed a framework enabling inter-subject comparison of partial volume corrected brain FDG-PET studies. The framework is composed of the following image processing steps: (1)MRI segmentation, (2)MR-PET registration, (3)MR based PVE correction, (4)MR 3D inter-subject elastic mapping. Through simulation studies, we showed that the newly developed partial volume correction methods, either pixel based or ROI based, performed better than previous methods. By applying this framework to a real Alzheimer's disease study, we demonstrated that the partial volume corrected glucose rates vary significantly among the control, at risk and disease patient groups and this framework is a promising tool useful for assisting early identification of Alzheimer's patients.

Yang, Jun

2000-12-01

334

Plasma volume considerations for analysis of gaseous and aerosol samples using laser-induced breakdown spectroscopy  

E-print Network

of laser- induced plasma-particle interactions. Due to plasma non-homogeneity, the particle vaporizationPlasma volume considerations for analysis of gaseous and aerosol samples using laser and diffusion, and is considered in terms of an equivalent emitting plasma volume. Introduction Laser

Hahn, David W.

335

Volume 18, number 4 CHEMICAL PHYSICS LETTERS 15February 1973 ANALYSIS OF POLYATOMIC $PECTRA  

E-print Network

Volume 18, number 4 CHEMICAL PHYSICS LETTERS 15February 1973 ANALYSIS OF POLYATOMIC $PECTRA USING. technical assistance. 46.5 #12;Volume 18. number 4 CHEMiCAL PHYSICS LETTERS 15 February 1973 ETALON BEAM TUNABLE LASER-INDUCED FLUORESCENCE: APPLICATIONS TO THE NO, VISIBLE BAND SYSTEM" C.G. STEVENS, h1.W

Zare, Richard N.

336

Comparison of CLASS and ITK-SNAP in segmentation of urinary bladder in CT urography  

NASA Astrophysics Data System (ADS)

We are developing a computerized method for bladder segmentation in CT urography (CTU) for computeraided diagnosis of bladder cancer. We have developed a Conjoint Level set Analysis and Segmentation System (CLASS) consisting of four stages: preprocessing and initial segmentation, 3D and 2D level set segmentation, and post-processing. In case the bladder contains regions filled with intravenous (IV) contrast and without contrast, CLASS segments the noncontrast (NC) region and the contrast (C) filled region separately and conjoins the contours. In this study, we compared the performance of CLASS to ITK-SNAP 2.4, which is a publicly available software application for segmentation of structures in 3D medical images. ITK-SNAP performs segmentation by using the edge-based level set on preprocessed images. The level set were initialized by manually placing a sphere at the boundary between the C and NC parts of the bladders with C and NC regions, and in the middle of the bladders that had only C or NC region. Level set parameters and the number of iterations were chosen after experimentation with bladder cases. Segmentation performances were compared using 30 randomly selected bladders. 3D hand-segmented contours were obtained as reference standard, and computerized segmentation accuracy was evaluated in terms of the average volume intersection %, average % volume error, average absolute % volume error, average minimum distance, and average Jaccard index. For CLASS, the values for these performance metrics were 79.0±8.2%, 16.1±16.3%, 19.9±11.1%, 3.5±1.3 mm, 75.7±8.4%, respectively. For ITK-SNAP, the corresponding values were 78.8±8.2%, 8.3±33.1%, 24.2±23.7%, 5.2±2.6 mm, 71.0±15.4%, respectively. CLASS on average performed better and exhibited less variations than ITK-SNAP for bladder segmentation.

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

2014-03-01

337

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 the current effectiveness of advertising engines. ­ Advertising engines might use different strategies a new ad- vertisement could potentially receive in the current market? This ques- tion, called the click

Lifshits, Yury

338

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

339

Evaluation of atlas based mouse brain segmentation  

NASA Astrophysics Data System (ADS)

Magentic Reasonance Imaging for mouse phenotype study is one of the important tools to understand human diseases. In this paper, we present a fully automatic pipeline for the process of morphometric mouse brain analysis. The method is based on atlas-based tissue and regional segmentation, which was originally developed for the human brain. To evaluate our method, we conduct a qualitative and quantitative validation study as well as compare of b-spline and fluid registration methods as components in the pipeline. The validation study includes visual inspection, shape and volumetric measurements and stability of the registration methods against various parameter settings in the processing pipeline. The result shows both fluid and b-spline registration methods work well in murine settings, but the fluid registration is more stable. Additionally, we evaluated our segmentation methods by comparing volume differences between Fmr1 FXS in FVB background vs C57BL/6J mouse strains.

Lee, Joohwi; Jomier, Julien; Aylward, Stephen; Tyszka, Mike; Moy, Sheryl; Lauder, Jean; Styner, Martin

2009-02-01

340

Evaluation of Atlas based Mouse Brain Segmentation  

PubMed Central

Magentic Reasonance Imaging for mouse phenotype study is one of the important tools to understand human diseases. In this paper, we present a fully automatic pipeline for the process of morphometric mouse brain analysis. The method is based on atlas-based tissue and regional segmentation, which was originally developed for the human brain. To evaluate our method, we conduct a qualitative and quantitative validation study as well as compare of b-spline and fluid registration methods as components in the pipeline. The validation study includes visual inspection, shape and volumetric measurements and stability of the registration methods against various parameter settings in the processing pipeline. The result shows both fluid and b-spline registration methods work well in murine settings, but the fluid registration is more stable. Additionally, we evaluated our segmentation methods by comparing volume differences between Fmr1 FXS in FVB background vs C57BL/6J mouse strains. PMID:20640188

Lee, Joohwi; Jomier, Julien; Aylward, Stephen; Tyszka, Mike; Moy, Sheryl; Lauder, Jean; Styner, Martin

2010-01-01

341

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

342

Applying principal components analysis to image time series: effects on scene segmentation and spatial structure  

Microsoft Academic Search

Principal components analysis (PCA) has been applied to multitemporal data for over a decade, frequently in preparation for land cover classification. With the increasing availability of standardized multitemporal datasets, such as Pathfinder AVHRR Land products and the maximum biweekly AVHRR NDVI composites for the conterminous US, the authors wondered about the efficacy of using PCA to identify the dominant spatio-temporal

Geoffrey M. Henebry; Donna R. Rieck

1996-01-01

343

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

E-print Network

and Statistical Analysis of T2-Hypointensities. PLoS ONE 8(7): e68196. doi:10.1371/journal.pone.0068196 Editor Abstract Aiming at iron-related T2-hypointensity, which is related to normal aging and neurodegenerative@lrz.tum.de Introduction This work was motivated by the aim to analyze iron-related T2- hypointensity automatically

Gaser, Christian

344

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

Microsoft Academic Search

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

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

1998-01-01

345

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

E-print Network

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

346

Impact Study Report. Volume II. An Analysis of Findings for Each Region.  

National Technical Information Service (NTIS)

Volume II of the Impact Study Report presents an analysis of findings for each region. The major components of the results are included: the extent of technical assistance activity, the perceived value, and the objectives accomplished and specific changes...

1979-01-01

347

Journal of Quantitative Analysis in Volume 6, Issue 3 2010 Article 8  

E-print Network

Journal of Quantitative Analysis in Sports Volume 6, Issue 3 2010 Article 8 A Point-Mass Mixture@gmail.com Kellogg School of Management, Northwestern University, b- mcshane@kellogg.northwestern.edu University

Jensen, Shane T.

348

Fast Segmentation of Cervical Cells by Using Spectral Imaging Analysis Techniques  

Microsoft Academic Search

Cervical cancer is the second most common cancer among women worldwide. Early detection of cervical cancer is very important\\u000a for successful treatment and increasing survival. We report a spectral imaging microscopic system for Papanicolaou smear analysis\\u000a for early detection of cervical cancer. Different from traditional color imaging method, we use spectral imaging techniques\\u000a for image acquisition, which can simultaneously record

Libo Zeng; Qiongshui Wu

2006-01-01

349

Remote sensing data acquisition analysis and archival. Volume 2. Appendices  

SciTech Connect

The project specialized in the acquisition and dissemination of satellite imagery and its utilization for case-specific and statistical analyses of offshore environmental conditions, particularly those involving sea ice. The topics included: Kasegaluk Lagoon transport, the effect of winter storms on arctic ice, the relationship between ice surface temperatures as measured by buoys and passive microwave imagery, unusual cloud forms following lead-openings, and analyses of Chukchi and Bering sea polynyas. The report is the appendices to Volume 1.

Stringer, W.J.; Dean, K.G.; Groves, J.E.

1993-03-25

350

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.

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

2014-01-01

351

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

352

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

353

The Extent of Pyrene Excimer Fluorescence Emission Is a Reflector of Distance and Flexibility: Analysis of the Segment Linking the LDL  

E-print Network

of apolipoprotein E3 (apoE3). Fluorescence spectral analysis revealed an intense excimer band when the probes were 5 in the tetrameric configuration of apoE. We infer that oligomerization via the C-terminal domain juxtaposes the linker segments from neighboring apoE molecules. This study offers new insights into the conformation

Sorin, Eric J.

354

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

E-print Network

62 LINCOLN LABORATORY JOURNAL VOLUME 20, NUMBER 1, 2013 SOCIAL NETWORK ANALYSIS WITH CONTENT AND GRAPHS Social Network Analysis with Content and Graphs William M. Campbell, Charlie K. Dagli in social network analysis. The quantity of content-based data created every day by traditional and social

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

Segmentation and Tracking of Multiple Moving Objects for Intelligent Video Analysis  

NASA Astrophysics Data System (ADS)

In recent years, there has been considerable interest in visual surveillance of a wide range of indoor and outdoor sites by various parties. This is manifested by the widespread and unabated deployment of CCTV cameras in public and private areas. In particular, the increasing connectivity of broadband wired and wireless IP networks, and the emergence of IP-CCTV systems with smart sensors, enabling centralised or distributed remote monitoring, have further fuelled this trend. It is not uncommon nowadays to see a bank of displays in an organisation showing the activities of dozens of surveillance sites simultaneously. However, the limitations and deficiencies, together with the costs associated with human operators in monitoring the overwhelming video sources, have created urgent demands for automated video analysis solutions. Indeed, the ability of a system to automatically analyse and interpret visual scenes is of increasing importance to decision making, offering enormous business opportunities in the sector of information and communications technologies.

Xu, L.-Q.; Landabaso, J. L.; Lei, B.

357

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

E-print Network

(traditional whole head GE HiSpeed RP CT scanner and the new dental CT Newtom 9000); 2) manual integration Reyes Enciso°*, MS, PhD,, Ahmed Memon°, BSEE, James Mah°, DDS, DMSc °Craniofacial Virtual Reality, memon, jamesmah} @usc.edu Keywords: 3D Visualization, volume rendering, CT, dentition models, jaw

Shahabi, Cyrus

358

Multifractal and singularity analysis of highway volume data  

NASA Astrophysics Data System (ADS)

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

Dai, Meifeng; Zhang, Cheng; Zhang, Danping

2014-08-01

359

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

360

Relationship between ST-segment resolution and anterior infarct size after primary percutaneous coronary intervention: analysis from the INFUSE-AMI trial  

PubMed Central

Aims: ST-segment resolution (STR) after reperfusion therapy has been shown to correlate with prognosis in patients with ST-segment elevation myocardial infarction (STEMI). We investigated whether acute ECG measurements also correlate with ultimate infarct size. Methods and Results: The INFUSE-AMI trial randomized 452 patients with anterior STEMI to intracoronary bolus abciximab vs. no abciximab, and to thrombus aspiration vs. no aspiration. Infarct size as percentage of total LV mass was calculated by cardiac magnetic resonance imaging (MRI) 30 days post intervention. Five ECG methods were analysed for their ability to predict MRI infarct mass: (1) summed STR across all infarct-related ECG leads (?STR); (2) STR in the single lead with maximum baseline ST-segment elevation (maxSTR); (3) summed residual ST-segment elevation across all infarct-related leads at 60 min post intervention (?ST residual); (4) maximum residual ST-segment elevation in the worst single lead at 60 min post intervention (maxST residual); (5) number of new significant Q-waves (Qwave) at 60 min. All ECG methods strongly correlated with 30-day MRI infarct mass (all p<0.003). Simpler ECG measurements such as maxSTresidual and Qwave were as predictive as more complex measurements. A subset analysis of 158 patients who had microvascular obstruction (MVO) determined by MRI 5 days post intervention also showed strong correlations of MVO with the ECG measures. Conclusions: ST-segment and Q-wave changes after primary PCI in anterior STEMI strongly correlated with 30-day infarct size by MRI. In particular, maxST residual and Qwave at 60 min are simple ECG parameters that offer rapid analysis for prognostication. PMID:24562806

Brener, Sorin J; Maehara, Akiko; Witzenbichler, Bernard; Biviano, Angelo; Godlewski, Jacek; Parise, Helen; Dambrink, Jan-Henk; Mehran, Roxana; Gibson, C Michael; Stone, Gregg W

2014-01-01

361

STEPS: Similarity and Truth Estimation for Propagated Segmentations and its application to hippocampal segmentation and brain parcelation.  

PubMed

Anatomical segmentation of structures of interest is critical to quantitative analysis in medical imaging. Several automated multi-atlas based segmentation propagation methods that utilise manual delineations from multiple templates appear promising. However, high levels of accuracy and reliability are needed for use in diagnosis or in clinical trials. We propose a new local ranking strategy for template selection based on the locally normalised cross correlation (LNCC) and an extension to the classical STAPLE algorithm by Warfield et al. (2004), which we refer to as STEPS for Similarity and Truth Estimation for Propagated Segmentations. It addresses the well-known problems of local vs. global image matching and the bias introduced in the performance estimation due to structure size. We assessed the method on hippocampal segmentation using a leave-one-out cross validation with optimised model parameters; STEPS achieved a mean Dice score of 0.925 when compared with manual segmentation. This was significantly better in terms of segmentation accuracy when compared to other state-of-the-art fusion techniques. Furthermore, due to the finer anatomical scale, STEPS also obtains more accurate segmentations even when using only a third of the templates, reducing the dependence on large template databases. Using a subset of Alzheimer's Disease Neuroimaging Initiative (ADNI) scans from different MRI imaging systems and protocols, STEPS yielded similarly accurate segmentations (Dice=0.903). A cross-sectional and longitudinal hippocampal volumetric study was performed on the ADNI database. Mean±SD hippocampal volume (mm(3)) was 5195 ± 656 for controls; 4786 ± 781 for MCI; and 4427 ± 903 for Alzheimer's disease patients and hippocampal atrophy rates (%/year) of 1.09 ± 3.0, 2.74 ± 3.5 and 4.04 ± 3.6 respectively. Statistically significant (p<10(-3)) differences were found between disease groups for both hippocampal volume and volume change rates. Finally, STEPS was also applied in a multi-label segmentation propagation scenario using a leave-one-out cross validation, in order to parcellate 83 separate structures of the brain. Comparisons of STEPS with state-of-the-art multi-label fusion algorithms showed statistically significant segmentation accuracy improvements (p<10(-4)) in several key structures. PMID:23510558

Jorge Cardoso, M; Leung, Kelvin; Modat, Marc; Keihaninejad, Shiva; Cash, David; Barnes, Josephine; Fox, Nick C; Ourselin, Sebastien

2013-08-01

362

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

NASA Technical Reports Server (NTRS)

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

1980-01-01

363

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

364

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

365

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

366

Cost-volume-profit and net present value analysis of health information systems.  

PubMed

The adoption of any information system should be justified by an economic analysis demonstrating that its projected benefits outweigh its projected costs. Analysis differ, however, on which methods to employ for such a justification. Accountants prefer cost-volume-profit analysis, and economists prefer net present value analysis. The article explains the strengths and weaknesses of each method and shows how they can be used together so that well-informed investments in information systems can be made. PMID:10181911

McLean, R A

1998-08-01

367

A Fuzzy, Nonparametric Segmentation Framework for DTI and MRI Analysis: With Applications to DTI-Tract Extraction  

Microsoft Academic Search

Abstract—This paper presents a novel fuzzy-segmentation method for diffusion tensor (DT) and magnetic resonance (MR) images. Typical fuzzy-segmentation schemes, e.g., those based on fuzzy C means (FCM), incorporate Gaussian class models that are inherently biased towards ellipsoidal clusters characterized by a mean element and a covariance matrix. Tensors in fiber bundles, however, inherently lie on specific manifolds in Riemannian spaces.

Suyash P. Awate; Hui Zhang; James C. Gee

2007-01-01

368

Do skeletal cephalometric characteristics correlate with condylar volume, surface and shape? A 3D analysis  

PubMed Central

Objective The purpose of this study was to determine the condylar volume in subjects with different mandibular divergence and skeletal class using cone-beam computed tomography (CBCT) and analysis software. Materials and methods For 94 patients (46 females and 48 males; mean age 24.3?±?6.5?years), resultant rendering reconstructions of the left and right temporal mandibular joints (TMJs) were obtained. Subjects were then classified on the base of ANB angle the GoGn-SN angle in three classes (I, II, III) . The data of the different classes were compared. Results No significant difference was observed in the whole sample between the right and the left sides in condylar volume. The analysis of mean volume among low, normal and high mandibular plane angles revealed a significantly higher volume and surface in low angle subjects (p?volume and surface than class I and class II subjects, although the difference was not significant. Conclusions Higher condylar volume was a common characteristic of low angle subjects compared to normal and high mandibular plane angle subjects. Skeletal class also appears to be associated to condylar volume and surface. PMID:22587445

2012-01-01

369

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

PubMed

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

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

2012-12-01

370

Underground Test Area Subproject Phase I Data Analysis Task. Volume IV - Hydrologic Parameter Data Documentation Package  

SciTech Connect

Volume IV 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 hydrologic parameter 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

1996-09-01

371

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

372

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

373

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

374

Influence of loading cycle profile and frequency on a biomechanical parameter of a model of a balloon kyphoplasty-augmented lumbar spine segment: a finite element analysis study.  

PubMed

For patients who are suffering debilitating and persistent pain due to vertebral compression fracture(s) and for whom conservative therapies have not provided relief, balloon kyphoplasty (BKP) is used as a surgical option. There are only a very few literature reports on the use of the finite element analysis (FEA) method to obtain biomechanical parameters of models of spine segments that include BKP augmentation at a given level. In each of these studies, the applied loading used was quasi-static. During normal activities of daily living, the patient's spine would be subject to dynamically-applied loading. Thus, the question of the influence of the characteristics of a dynamically-applied loading cycle on biomechanical parameters of a spine that includes BKP-augmented segment(s) is germane; however, a study of this issue is lacking. We investigated this issue in the present FEA work, with the spine segment model being the L1-L3 motion segment units (MSUs) (a segment that is commonly augmented using BKP) and prophylactic BKP simulated at L2. The dynamic load was the compressive load-versus-time cycle to which the L3-L4 MSU is subjected during gait. Four cases of the cycle were considered, corresponding to slow-, normal-, fast- and very fast-paced gait. The loading cycle was applied to the superior surface of L1 while the inferior surface of L3 was fully constrained. It was found that (1) the global mean von Mises stress during the loading cycle (?VMG), in each tissue in the model increased in going from a slow-paced gait cycle to a very fast-paced gait cycle; and (2) for the slow-paced gait cycle, with increase in frequency of the cycle, f (1 ? f ? 3 Hz), ?VMG in each of these tissues increased. Potential uses of the present findings are identified. PMID:21263181

Li, Yuan; Lewis, Gladius

2010-01-01

375

Photovoltaic Venture Analysis. Final Report. Volume II. Appendices.  

National Technical Information Service (NTIS)

A description of the integrating model for photovoltaic venture analysis is given; input assumptions for the model are described; and the integrating model program listing is given. The integrating model is an explicit representation of the interactions b...

D. Costello, D. Posner, D. Schiffel, J. Doane, C. Bishop

1978-01-01

376

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

377

Dose-volume analysis for quality assurance of interstitial brachytherapy for breast cancer  

Microsoft Academic Search

Purpose\\/Objective: The use of brachytherapy in the management of breast cancer has increased significantly over the past several years. Unfortunately, few techniques have been developed to compare dosimetric quality and target volume coverage concurrently. We present a new method of implant evaluation that incorporates computed tomography-based three-dimensional (3D) dose-volume analysis with traditional measures of brachytherapy quality. Analyses performed in this

Frank A. Vicini; Larry L. Kestin; Gregory K. Edmundson; David A. Jaffray; John W. Wong; Vijay R. Kini; Peter Y. Chen; Alvaro A. Martinez

1999-01-01

378

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

379

Reduced field-of-view DTI segmentation of cervical spine tissue.  

PubMed

The number of diffusion tensor imaging (DTI) studies regarding the human spine has considerably increased and it is challenging because of the spine's small size and artifacts associated with the most commonly used clinical imaging method. A novel segmentation method based on the reduced field-of-view (rFOV) DTI dataset is presented in cervical spinal canal cerebrospinal fluid, spinal cord grey matter and white matter classification in both healthy volunteers and patients with neuromyelitis optica (NMO) and multiple sclerosis (MS). Due to each channel based on high resolution rFOV DTI images providing complementary information on spinal tissue segmentation, we want to choose a different contribution map from multiple channel images. Via principal component analysis (PCA) and a hybrid diffusion filter with a continuous switch applied on fourteen channel features, eigen maps can be obtained and used for tissue segmentation based on the Bayesian discrimination method. Relative to segmentation by a pair of expert readers, all of the automated segmentation results in the experiment fall in the good segmentation area and performed well, giving an average segmentation accuracy of about 0.852 for cervical spinal cord grey matter in terms of volume overlap. Furthermore, this has important applications in defining more accurate human spinal cord tissue maps when fusing structural data with diffusion data. rFOV DTI and the proposed automatic segmentation outperform traditional manual segmentation methods in classifying MR cervical spinal images and might be potentially helpful for detecting cervical spine diseases in NMO and MS. PMID:23993792

Tang, Lihua; Wen, Ying; Zhou, Zhenyu; von Deneen, Karen M; Huang, Dehui; Ma, Lin

2013-11-01

380

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

381

Compatibility of segmented thermoelectric generators  

NASA Technical Reports Server (NTRS)

It is well known that power generation efficiency improves when materials with appropriate properties are combined either in a cascaded or segmented fashion across a temperature gradient. Past methods for determining materials used in segmentation weremainly concerned with materials that have the highest figure of merit in the temperature range. However, the example of SiGe segmented with Bi2Te3 and/or various skutterudites shows a marked decline in device efficiency even though SiGe has the highest figure of merit in the temperature range. The origin of the incompatibility of SiGe with other thermoelectric materials leads to a general definition of compatibility and intrinsic efficiency. The compatibility factor derived as = (Jl+zr - 1) a is a function of only intrinsic material properties and temperature, which is represented by a ratio of current to conduction heat. For maximum efficiency the compatibility factor should not change with temperature both within a single material, and in the segmented leg as a whole. This leads to a measure of compatibility not only between segments, but also within a segment. General temperature trends show that materials are more self compatible at higher temperatures, and segmentation is more difficult across a larger -T. The compatibility factor can be used as a quantitative guide for deciding whether a material is better suited for segmentation orcascading. Analysis of compatibility factors and intrinsic efficiency for optimal segmentation are discussed, with intent to predict optimal material properties, temperature interfaces, and/or currentheat ratios.

Snyder, J.; Ursell, T.

2002-01-01

382

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

383

SLUDGE TREATMENT PROJECT ALTERNATIVES ANALYSIS SUMMARY REPORT [VOLUME 1  

SciTech Connect

Highly radioactive sludge (containing up to 300,000 curies of actinides and fission products) resulting from the storage of degraded spent nuclear fuel is currently stored in temporary containers located in the 105-K West storage basin near the Columbia River. The background, history, and known characteristics of this sludge are discussed in Section 2 of this report. There are many compelling reasons to remove this sludge from the K-Basin. These reasons are discussed in detail in Section1, and they include the following: (1) Reduce the risk to the public (from a potential release of highly radioactive material as fine respirable particles by airborne or waterborn pathways); (2) Reduce the risk overall to the Hanford worker; and (3) Reduce the risk to the environment (the K-Basin is situated above a hazardous chemical contaminant plume and hinders remediation of the plume until the sludge is removed). The DOE-RL has stated that a key DOE objective is to remove the sludge from the K-West Basin and River Corridor as soon as possible, which will reduce risks to the environment, allow for remediation of contaminated areas underlying the basins, and support closure of the 100-KR-4 operable unit. The environmental and nuclear safety risks associated with this sludge have resulted in multiple legal and regulatory remedial action decisions, plans,and commitments that are summarized in Table ES-1 and discussed in more detail in Volume 2, Section 9.

FREDERICKSON JR; ROURK RJ; HONEYMAN JO; JOHNSON ME; RAYMOND RE

2009-01-19

384

Viscous wing theory development. Volume 1: Analysis, method and results  

NASA Technical Reports Server (NTRS)

Viscous transonic flows at large Reynolds numbers over 3-D wings were analyzed using a zonal viscid-inviscid interaction approach. A new numerical AFZ scheme was developed in conjunction with the finite volume formulation for the solution of the inviscid full-potential equation. A special far-field asymptotic boundary condition was developed and a second-order artificial viscosity included for an improved inviscid solution methodology. The integral method was used for the laminar/turbulent boundary layer and 3-D viscous wake calculation. The interaction calculation included the coupling conditions of the source flux due to the wing surface boundary layer, the flux jump due to the viscous wake, and the wake curvature effect. A method was also devised incorporating the 2-D trailing edge strong interaction solution for the normal pressure correction near the trailing edge region. A fully automated computer program was developed to perform the proposed method with one scalar version to be used on an IBM-3081 and two vectorized versions on Cray-1 and Cyber-205 computers.

Chow, R. R.; Melnik, R. E.; Marconi, F.; Steinhoff, J.

1986-01-01

385

Finite element analysis of laminated plates and shells, volume 1  

NASA Technical Reports Server (NTRS)

The finite element method is used to investigate the static behavior of laminated composite flat plates and cylindrical shells. The analysis incorporates the effects of transverse shear deformation in each layer through the assumption that the normals to the undeformed layer midsurface remain straight but need not be normal to the mid-surface after deformation. A digital computer program was developed to perform the required computations. The program includes a very efficient equation solution code which permits the analysis of large size problems. The method is applied to the problem of stretching and bending of a perforated curved plate.

Seide, P.; Chang, P. N. H.

1978-01-01

386

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

387

Morphotectonic segmentation and spatial variability of neotectonic activity along the Narmada-Son Fault, Western India: Remote sensing and GIS analysis  

NASA Astrophysics Data System (ADS)

Morphotectonic analysis of landscape using remote sensing and GIS is an effective way of deducing the pattern and spatial variation of neotectonic activity along poorly investigated active faults. In this paper, we evaluate the neotectonic activity along a part of the seismically active but poorly understood Narmada-Son Fault (NSF), a more than 1000 km long ENE-WSW trending fault transecting through the central part of the Indian plate. The NSF in the study area is geomorphologically expressed as an ENE-WSW trending line of north facing scarps that delimit the rugged mountainous topography of the uplands to the south and the alluvial basin to the north which prominently slope away from the scarps. The scarps are developed in the south dipping basaltic flows belonging to the Deccan Trap Formation of the late Cretaceous-Eocene and continue westward into Tertiary rocks and further as a paleobank of the Narmada River. Field studies have revealed that the NSF in the study area is divisible into four morphotectonic segments (I to IV), which is attributed to the Tilakwada, Karjan, Madhumati and Rajpardi Faults cutting across the NSF. We characterize the neotectonic activity of the segments through DEM analysis, using geomorphic indices which include the mountain front sinuosity, hypsometric curves, hypsometric integral, asymmetry factor, stream length-gradient index and channel sinuosity. Interpretations of morphometric data are well supported by field data. Both the entire length of the NSF and the cross faults are found to be neotectonically active. We demonstrate that segment II has undergone the highest intensity of neotectonic activity followed by segments III, I and IV. This is corroborated by the highest elevation of scarps and the alluvial deposits, the deepest incision (~ 40 m depth) and steep northward slope of the alluvial plain in segment II. We infer that the NSF is characterized by differential uplift in recent past which agrees with the high angle reverse faulting with oblique-slip movements along the cross faults.

Joshi, Parul N.; Maurya, D. M.; Chamyal, L. S.

2013-01-01

388

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

389

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

390

Spaceborne power systems preference analyses. Volume 2: Decision analysis  

NASA Technical Reports Server (NTRS)

Sixteen alternative spaceborne nuclear power system concepts were ranked using multiattribute decision analysis. The purpose of the ranking was to identify promising concepts for further technology development and the issues associated with such development. Four groups were interviewed to obtain preference. The four groups were: safety, systems definition and design, technology assessment, and mission analysis. The highest ranked systems were the heat-pipe thermoelectric systems, heat-pipe Stirling, in-core thermionic, and liquid-metal thermoelectric systems. The next group contained the liquid-metal Stirling, heat-pipe Alkali Metal Thermoelectric Converter (AMTEC), heat-pipe Brayton, liquid-metal out-of-core thermionic, and heat-pipe Rankine systems. The least preferred systems were the liquid-metal AMTEC, heat-pipe thermophotovoltaic, liquid-metal Brayton and Rankine, and gas-cooled Brayton. The three nonheat-pipe technologies selected matched the top three nonheat-pipe systems ranked by this study.

Smith, J. H.; Feinberg, A.; Miles, R. F., Jr.

1985-01-01

391

Passive solar design handbook. Volume 3: Passive solar design analysis  

NASA Astrophysics Data System (ADS)

Simple analytical methods concerning the design of passive solar heating systems are presented with an emphasis on the average annual heating energy consumption. Key terminology and methods are reviewed. The solar load ratio (SLR) is defined, and its relationship to analysis methods is reviewed. The annual calculation, or Load Collector Ratio (LCR) method, is outlined. Sensitivity data are discussed. Information is presented on balancing conservation and passive solar strategies in building design. Detailed analysis data are presented for direct gain and sunspace systems, and details of the systems are described. Key design parameters are discussed in terms of their impact on annual heating performance of the building. These are the sensitivity data. The SLR correlations for the respective system types are described. The monthly calculation, or SLR method, based on the SLR correlations, is reviewed. Performance data are given for 9 direct gain systems and 15 water wall and 42 Trombe wall systems.

Jones, R. W.; Bascomb, J. D.; Kosiewicz, C. E.; Lazarus, G. S.; McFarland, R. D.; Wray, W. O.

1982-07-01

392

Integrated operations/payloads/fleet analysis. Volume 2: Payloads  

NASA Technical Reports Server (NTRS)

The payloads for NASA and non-NASA missions of the integrated fleet are analyzed to generate payload data for the capture and cost analyses for the period 1979 to 1990. Most of the effort is on earth satellites, probes, and planetary missions because of the space shuttle's ability to retrieve payloads for repair, overhaul, and maintenance. Four types of payloads are considered: current expendable payload; current reusable payload; low cost expendable payload, (satellite to be used with expendable launch vehicles); and low cost reusable payload (satellite to be used with the space shuttle/space tug system). Payload weight analysis, structural sizing analysis, and the influence of mean mission duration on program cost are also discussed. The payload data were computerized, and printouts of the data for payloads for each program or mission are included.

1971-01-01

393

Prevention of altered hemodynamics after spinal anesthesia: A comparison of volume preloading with tetrastarch, succinylated gelatin and ringer lactate solution for the patients undergoing lower segment caesarean section  

PubMed Central

Background: Spinal anesthesia has replaced general anesthesia in obstetric practice. Hemodynamic instability is a common, but preventable complication of spinal anesthesia. Preloading the circulation with intravenous fluids is considered a safe and effective method of preventing hypotension following spinal anesthesia. We had conducted a study to compare the hemodynamic stability after volume preloading with either Ringer's lactate (RL) or tetrastarch hydroxyethyl starch (HES) or succinylated gelatin (SG) in the patients undergoing cesarean section under spinal anesthesia. Materials and Methods: It was a prospective, double-blinded and randomized controlled study. Ninety six ASA-I healthy, nonlaboring parturients were randomly divided in 3 groups HES, SG, RL (n = 32 each) and received 10 ml/kg HES 130/0.4; 10 ml/kg SG (4% modified fluid gelatin) and 20 ml/kg RL respectively prior to SA scheduled for cesarean section. Heart rate, blood pressure (BP), oxygen saturation was measured. Results: The fall in systolic blood pressure (SBP) (<100 mm Hg) noted among 5 (15.63%), 12 (37.5%) and 14 (43.75%) parturients in groups HES, SG, RL respectively. Vasopressor (phenylephrine) was used to treat hypotension when SBP <90 mm Hg. Both the results and APGAR scores were comparable in all the groups. Lower preloading volume and less intra-operative vasopressor requirement was noted in HES group for maintaining BP though it has no clinical significance. Conclusion: RL which is cheap, physiological and widely available crystalloid can preload effectively and maintain hemodynamic stability well in cesarean section and any remnant hypotension can easily be manageable with vasopressor.

Mitra, Tapobrata; Das, Anjan; Majumdar, Saikat; Bhattacharyya, Tapas; Mandal, Rahul Deb; Hajra, Bimal Kumar

2014-01-01

394

Satellite services system analysis study. Volume 5: Programmatics  

NASA Technical Reports Server (NTRS)

The overall program and resources needed for development and operation of a Satellite Services System is reviewed. Program requirements covered system operations through 1993 and were completed in preliminary form. Program requirements were refined based on equipment preliminary design and analysis. Schedules, costs, equipment utilization, and facility/advanced technology requirements were included in the update. Equipment user charges were developed for each piece of equipment and for representative satellite servicing missions.

1981-01-01

395

Space tug economic analysis study. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

An economic analysis of space tug operations is presented. The space tug is defined as any liquid propulsion stage under 100,000 pounds propellant loading that is flown from the space shuttle cargo bay. Two classes of vehicles are the orbit injection stages and reusable space tugs. The vehicle configurations, propellant combinations, and operating modes used for the study are reported. The summary contains data on the study approach, results, conclusions, and recommendations.

1972-01-01

396

Genetic differentiation and phylogenetic relationships among Greek Salmo trutta L. (brown trout) populations as revealed by RFLP analysis of PCR amplified mitochondrial DNA segments  

Microsoft Academic Search

The genetic differentiation and phylogenetic relationships of 13 populations (11 from Greece, one from Albania and one from France) of brown trout (Salmo trutta L.) were investigated at the mtDNA level. RFLP analysis of four segments of mitochondrial DNA (D-loop, cytochrome b and ND-5\\/6) amplified by PCR was used. Seven of 14 restriction endonucleases were found to detect variability in

A P Apostolidis; Y Karakousis; C Triantaphyllidis

1996-01-01

397

Random harmonic analysis program, L221 (TEV156). Volume 2: Supplemental system design and maintenenace document  

NASA Technical Reports Server (NTRS)

Volume 2 of a two volume document is presented. A computer program, L222 (TEV 156), available for execution on the CDC 6600 computer is described. The program is capable of calculating steady-state solutions for linear second-order differential equations due to sinusoidal forcing functions. From this, steady-state solutions, generalized coordinates, and load frequency responses may be determined. Statistical characteristics of loads for the forcing function spectral shape may also be calculated using random harmonic analysis techniques. The particular field of application of the program is the analysis of airplane response and loads due to continuous random air turbulence.

Graham, M. L.; Clemmons, R. E.; Miller, R. D.

1979-01-01

398

Segmenting the mental health care market.  

PubMed

The authors report the results of a segmentation study of the mental health care market. A random sample of 387 residents of a western city were interviewed by telephone. Cluster analysis of the data identified six market segments. Each is described according to the mental health care services to which it is most sensitive. Implications for targeting the segments are discussed. PMID:10104017

Stone, T R; Warren, W E; Stevens, R E

1990-03-01

399

Mining reference tables for automatic text segmentation  

Microsoft Academic Search

Automatically segmenting unstructured text strings into structured records is necessary for importing the information contained in legacy sources and text collections into a data warehouse for subsequent querying, analysis, mining and integration. In this paper, we mine tables present in data warehouses and relational databases to develop an automatic segmentation system. Thus, we overcome limitations of existing supervised text segmentation

Eugene Agichtein; Venkatesh Ganti

2004-01-01

400

Segmenting Images Corrupted by Correlated Noise  

Microsoft Academic Search

Image segmentation is fundamental to many image analysis problems. It aims to partition a digital image into a set of non-overlapping homogeneous regions. This paper describes a new segmentation procedure which is designed to segment images corrupted by correlated noise. This procedure is based on Rissanen's (1989) minimum description length principle

Thomas C. M. Lee

1997-01-01

401

Segmenting Images Corrupted by Correlated Noise  

Microsoft Academic Search

Image segmentation is fundamental to many image analysis problems. It aims topartition a digital image into a set of non--overlapping homogeneous regions. The maincontribution of this paper is the development of a new segmentation procedure whichis designed to segment images corrupted by correlated noise. This new segmentationprocedure is based on Rissanen's minimum description length (MDL) principle andconsists of two components:

Thomas C. M. Lee

1998-01-01

402

Analysis of space tug operating techniques. Volume 2: Study results  

NASA Technical Reports Server (NTRS)

The design requirements for space tug systems and cost analysis of the refurbishment phases are discussed. The vehicle is an integral propulsion stage using liquid hydrogen and liquid oxygen as propellants and is capable of operating either as a fully or a partially autonomous vehicle. Structural features are an integral liquid hydrogen tank, a liquid oxygen tank, a meteoroid shield, an aft conical docking and structural support ring, and a staged combustion main engine. The vehicle is constructed of major modules for ease of maintenance. Line drawings and block diagrams are included to explain the maintenance requirements for the subsystems.

1972-01-01

403

Development of a rotorcraft. Propulsion dynamics interface analysis, volume 2  

NASA Technical Reports Server (NTRS)

A study was conducted to establish a coupled rotor/propulsion analysis that would be applicable to a wide range of rotorcraft systems. The effort included the following tasks: (1) development of a model structure suitable for simulating a wide range of rotorcraft configurations; (2) defined a methodology for parameterizing the model structure to represent a particular rotorcraft; (3) constructing a nonlinear coupled rotor/propulsion model as a test case to use in analyzing coupled system dynamics; and (4) an attempt to develop a mostly linear coupled model derived from the complete nonlinear simulations. Documentation of the computer models developed is presented.

Hull, R.

1982-01-01

404

County: Bannock Station # 074 District: 05 Route: US91 Ascending Direction: Northwest Segment Code and Milepost: 002350 041.517 1.0 Miles S.E. of Jct I-15 (Virginia) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 25 1.5% 5 0.3% 8 0.5% 8 0.4% 7 0.4% 15 0.7% 20 1.0% 7 0.4% 22 1.2%

Sunday Monday

2007-01-01

405

County: Lincoln Station # 014 District: 04 Route: SH75 Ascending Direction: North Segment Code and Milepost: 002230 079.670 6.0 Miles North of North Rail St (Shoshone) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 37 0.9% 16 0.4% 12 0.3% 13 0.3% 21 0.5% 22 0.4% 35 0.8% 16 0.4% 36 0.8%

Sunday Monday

2005-01-01

406

County: Ada Station # 010 District: 03 Route: SH55 Ascending Direction: North Segment Code and Milepost: 001990 047.830 3.3 Miles North of Jct SH44 (Dry Creek) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 58 0.6% 33 0.4% 32 0.5% 22 0.4% 23 0.3% 34 0.4% 58 0.7% 28 0.4% 58 0.7%

Sunday Monday

2005-01-01

407

Station # 182 District: 03 Route: SH55 Ascending Direction: North Segment Code and Milepost: 001990 078.864 230 Ft N of Garden Valley Road (N. Banks) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 10 0.3% 6 0.3% 6 0.4% 6 0.4% 7 0.4% 7 0.2% 12 0.3% 6 0.3% 11 0.3%

Sunday Monday

2009-01-01

408

Station # 114 District: 01 Route: US2 Ascending Direction: Southeast Segment Code and Milepost: 001590 079.389 1.9 Miles N.W. of Idaho\\/Montana State Line (Moyie Springs) Volumes and Percent of Daily Traffic  

Microsoft Academic Search

Hour Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day Volume % of day 0:00 9 0.8% 5 0.5% 10 0.9% 9 0.8% 10 0.8% 9 0.7% 9 0.8% 8 0.7% 9 0.8%

Sunday Monday

2006-01-01

409

Choroidal volume variations with age, axial length, and sex in healthy subjects: a three-dimensional analysis  

PubMed Central

Purpose To demonstrate the three-dimensional choroidal volume distribution in healthy subjects using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT) and to evaluate its association with age, sex, and axial length. Design Retrospective case series. Participants One hundred and seventy six eyes from 114 subjects with no retinal or choroidal disease. Methods EDI SD-OCT imaging studies for healthy patients who had undergone a 31-raster scanning protocol on a commercial SD-OCT device were reviewed. Manual segmentation of the choroid was performed by two retinal specialists. Macular choroidal volume map and three-dimensional topography were automatically created by the built-in software of the device. Mean choroidal volume was calculated for each Early Treatment Diabetic Retinopathy Study (ETDRS) subfield. Regression analyses were used to evaluate the correlation between macular choroidal volume and age, sex, and axial length. Main Outcome Measures Three-dimensional topography and ETDRS-style volume map of the choroid. Results Three-dimensional topography of the choroid and volume map was obtained in all cases. The mean choroidal volume was 0.228 ± 0.077 mm3 for the center ring and 7.374 ± 2.181 mm3 for the total ETDRS grid. The nasal quadrant showed the lowest choroidal volume, and the superior quadrant the highest. The temporal and inferior quadrants did not show different choroidal volume values. Choroidal volume in all the EDTRS rings was significantly correlated with axial length after adjustment for age (P<0.0001), with age after adjustment for axial length (P<0.0001) and with sex after adjustment for axial length (P<0.05). Choroidal volume decreases by 0.54 mm3 (7.32%) for every decade and by 0.56 mm3 (7.59%) for every mm of axial length. Males have a 7.37% greater choroidal volume compared to that of females. Conclusions EDI SD-OCT is non-invasive and well-tolerated procedure with an excellent ability to visualize three-dimensional topography of the choroid and to measure choroidal volume at the posterior pole using manual segmentation. Age and axial length are inversely correlated with choroidal volume, most likely leading to changes in retinal metabolic support in old and high myopic patients. Sexual differences should be considered when interpreting an EDI SD-OCT scan of the choroid. PMID:22921388

Barteselli, Giulio; Chhablani, Jay; El-Emam, Sharif; Wang, Haiyan; Chuang, Janne; Kozak, Igor; Cheng, Lingyun; Bartsch, Dirk-Uwe; Freeman, William R.

2012-01-01

410

Oil-spill risk analysis: Cook inlet outer continental shelf lease sale 149. Volume 1. The analysis. Final report  

SciTech Connect

This report summarizes results of an oil-spill risk analysis (OSRA) conducted for the proposed lower Cook Inlet Outer Continental Shelf (OCS) Lease Sale 149. The objective of this analysis was to estimate relative oil-spill risks associated with oil and gas production from the leasing alternatives proposed for the lease sale. The Minerals Management Service (MMS) will consider the analysis in the environmental impact statement (EIS) prepared for the lease sale. The analysis for proposed OCS Lease Sale 149 was conducted in three parts corresponding to different aspects of the overall problem. The first part dealt with the probability of oil-spill occurrence. The second dealt with trajectories of oil spills from potential spill sites to various environmental resources or land segments. The third part combined the results of the first two parts to give estimates of the overall oil-spill risk if there is oil production as a result of the 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 (see vol. 2).

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

1994-08-01

411

Wind tunnel test IA300 analysis and results, volume 1  

NASA Technical Reports Server (NTRS)

The analysis and interpretation of wind tunnel pressure data from the Space Shuttle wind tunnel test IA300 are presented. The primary objective of the test was to determine the effects of the Space Shuttle Main Engine (SSME) and the Solid Rocket Booster (SRB) plumes on the integrated vehicle forebody pressure distributions, the elevon hinge moments, and wing loads. The results of this test will be combined with flight test results to form a new data base to be employed in the IVBC-3 airloads analysis. A secondary objective was to obtain solid plume data for correlation with the results of gaseous plume tests. Data from the power level portion was used in conjunction with flight base pressures to evaluate nominal power levels to be used during the investigation of changes in model attitude, eleveon deflection, and nozzle gimbal angle. The plume induced aerodynamic loads were developed for the Space Shuttle bases and forebody areas. A computer code was developed to integrate the pressure data. Using simplified geometrical models of the Space Shuttle elements and components, the pressure data were integrated to develop plume induced force and moments coefficients that can be combined with a power-off data base to develop a power-on data base.

Kelley, P. B.; Beaufait, W. B.; Kitchens, L. L.; Pace, J. P.

1987-01-01

412

Improved Inference in Bayesian Segmentation Using Monte Carlo Sampling: Application to Hippocampal Subfield Volumetry  

PubMed Central

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; Leemput, Koen Van

2013-01-01

413

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

414

Review of Department of Defense Education Activity (DoDEA) Schools. Volume II: Quantitative Analysis of Educational Quality. IDA Paper.  

ERIC Educational Resources Information Center

This volume compiles, and presents in integrated form, the Institute for Defense Analyses' (IDA) quantitative analysis of educational quality provided by the Department of Defense's dependent schools. It covers the quantitative aspects of volume 1 in greater detail and presents some analyses deemed too technical for that volume. The first task in…

Anderson, Lowell Bruce; Bracken, Jerome; Bracken, Marilyn C.

415

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