Science.gov

Sample records for computed tomography-a preliminary

  1. Preliminary Experimental Results on Controlled Cardiac Computed Tomography: A Phantom Study

    PubMed Central

    Lu, Yang; Cai, Zhijun; Wang, Ge; Zhao, Jun; Bai, Er-Wei

    2010-01-01

    In this paper, we present the preliminary experimental results on controlled cardiac computed tomography (CT), which aims to reduce the motion artifacts by means of controlling the x-ray source rotation speed. An innovative cardiac phantom enables us to perform this experiment without modifying the scanner. It is the first experiment on the cardiac CT with speed controlled x-ray source. Experimental results demonstrate that the proposed method successfully separates the phantom images at different phases (improve the temporal resolution) though controlling the x-ray speed. PMID:19696470

  2. Nanoparticle Contrast Agents for Computed Tomography: A Focus on Micelles

    PubMed Central

    Cormode, David P.; Naha, Pratap C.; Fayad, Zahi A.

    2014-01-01

    Computed tomography (CT) is an X-ray based whole body imaging technique that is widely used in medicine. Clinically approved contrast agents for CT are iodinated small molecules or barium suspensions. Over the past seven years there has been a great increase in the development of nanoparticles as CT contrast agents. Nanoparticles have several advantages over small molecule CT contrast agents, such as long blood-pool residence times, and the potential for cell tracking and targeted imaging applications. Furthermore, there is a need for novel CT contrast agents, due to the growing population of renally impaired patients and patients hypersensitive to iodinated contrast. Micelles and lipoproteins, a micelle-related class of nanoparticle, have notably been adapted as CT contrast agents. In this review we discuss the principles of CT image formation and the generation of CT contrast. We discuss the progress in developing non-targeted, targeted and cell tracking nanoparticle CT contrast agents. We feature agents based on micelles and used in conjunction with spectral CT. The large contrast agent doses needed will necessitate careful toxicology studies prior to clinical translation. However, the field has seen tremendous advances in the past decade and we expect many more advances to come in the next decade. PMID:24470293

  3. X-ray diffraction computed tomography: a survey and description

    NASA Astrophysics Data System (ADS)

    Kleuker, Ulf

    1997-10-01

    Coherently scattered x-rays are mainly confined to a forward peaked cone, which exhibits, due to their coherence, structural information of the atomic arrangement in the sample. Coherent scattering in amorphous materials, which are of random short range order, therefore results in board diffraction ring patter, whereas crystalline substance show more confined diffraction rings or even Brag spots. X-ray diffraction computed tomography (XRDCT) reconstructs the intensities diffracted from extended objects on a square image grid and thus retrieves the local structure. A short survey is presented about what information can be extracted from diffraction experiments. Hereby a new method is proposed to use the Rietveld refinement for quantitative XRDCT. Also the possible use of XRDCT to reconstruct the spatial distribution of preferred orientation axis is suggested. An imaging system for XRDCT, consisting of a medical image intensifier tube and CCD readout system, is presented, which includes a modified beam stop for recording the intensity of the transmitted beam. Depending on the application this imaging system cam work in first generation or second generation tomography mode. Furthermore a new approach for the reconstruction of the differential coherent cross-section is proposed. It includes an absorption correction based on weighted sinograms. The introduced reconstruction strategy is elucidated by experimental result from a simple phantom. The measured data also validate the simulation program, written to study more complex phantoms under different experimental conditions. Finally possible applications in medical and material science are discussed. A design for a mammography setup using x-ray diffraction is presented.

  4. Neutron stimulated emission computed tomography: a Monte Carlo simulation approach.

    PubMed

    Sharma, A C; Harrawood, B P; Bender, J E; Tourassi, G D; Kapadia, A J

    2007-10-21

    A Monte Carlo simulation has been developed for neutron stimulated emission computed tomography (NSECT) using the GEANT4 toolkit. NSECT is a new approach to biomedical imaging that allows spectral analysis of the elements present within the sample. In NSECT, a beam of high-energy neutrons interrogates a sample and the nuclei in the sample are stimulated to an excited state by inelastic scattering of the neutrons. The characteristic gammas emitted by the excited nuclei are captured in a spectrometer to form multi-energy spectra. Currently, a tomographic image is formed using a collimated neutron beam to define the line integral paths for the tomographic projections. These projection data are reconstructed to form a representation of the distribution of individual elements in the sample. To facilitate the development of this technique, a Monte Carlo simulation model has been constructed from the GEANT4 toolkit. This simulation includes modeling of the neutron beam source and collimation, the samples, the neutron interactions within the samples, the emission of characteristic gammas, and the detection of these gammas in a Germanium crystal. In addition, the model allows the absorbed radiation dose to be calculated for internal components of the sample. NSECT presents challenges not typically addressed in Monte Carlo modeling of high-energy physics applications. In order to address issues critical to the clinical development of NSECT, this paper will describe the GEANT4 simulation environment and three separate simulations performed to accomplish three specific aims. First, comparison of a simulation to a tomographic experiment will verify the accuracy of both the gamma energy spectra produced and the positioning of the beam relative to the sample. Second, parametric analysis of simulations performed with different user-defined variables will determine the best way to effectively model low energy neutrons in tissue, which is a concern with the high hydrogen content in

  5. Upper crustal structure beneath East Java from ambient noise tomography: A preliminary result

    NASA Astrophysics Data System (ADS)

    Martha, Agustya Adi; Widiyantoro, Sri; Cummins, Phil; Saygin, Erdinc; Masturyono

    2015-04-01

    East Java has a fairly complex geological structure. Physiographically East Java can be divided into three zones, i.e. the Southern Mountains zone in the southern part, the Kendeng zone in the middle part, and the Rembang zone in the northern part. Most of the seismic hazards in this region are due to processes in the upper crust. In this study, the Ambient Noise Tomography (ANT) method is used to image the upper crustal structure beneath East Java. We have used seismic waveform data recorded by 8Meteorological, Climatological and Geophysical Agency (BMKG) stationary seismographic stations and 16 portable seismographs installed for 2 to 8 weeks. The data were processed to obtain waveforms fromnoise cross-correlation between pairs of seismographic stations. Our preliminary results indicate that the Kendeng zone, an area of low gravity anomaly, is associated with a low velocity zone. On the other hand, the southern mountain range, which has a high gravity anomaly, is related to a high velocity anomaly as shown by our tomographic images.

  6. Upper crustal structure beneath East Java from ambient noise tomography: A preliminary result

    SciTech Connect

    Martha, Agustya Adi; Widiyantoro, Sri; Cummins, Phil; Saygin, Erdinc; Masturyono

    2015-04-24

    East Java has a fairly complex geological structure. Physiographically East Java can be divided into three zones, i.e. the Southern Mountains zone in the southern part, the Kendeng zone in the middle part, and the Rembang zone in the northern part. Most of the seismic hazards in this region are due to processes in the upper crust. In this study, the Ambient Noise Tomography (ANT) method is used to image the upper crustal structure beneath East Java. We have used seismic waveform data recorded by 8Meteorological, Climatological and Geophysical Agency (BMKG) stationary seismographic stations and 16 portable seismographs installed for 2 to 8 weeks. The data were processed to obtain waveforms fromnoise cross-correlation between pairs of seismographic stations. Our preliminary results indicate that the Kendeng zone, an area of low gravity anomaly, is associated with a low velocity zone. On the other hand, the southern mountain range, which has a high gravity anomaly, is related to a high velocity anomaly as shown by our tomographic images.

  7. Preliminary blade design using integrated computer codes

    NASA Astrophysics Data System (ADS)

    Ryan, Arve

    1988-12-01

    Loads on the root of a horizontal axis wind turbine (HAWT) rotor blade were analyzed. A design solution for the root area is presented. The loads on the blades are given by different load cases that are specified. To get a clear picture of the influence of different parameters, the whole blade is designed from scratch. This is only a preliminary design study and the blade should not be looked upon as a construction reference. The use of computer programs for the design and optimization is extensive. After the external geometry is set and the aerodynamic loads calculated, parameters like design stresses and laminate thicknesses are run through the available programs, and a blade design optimized on basis of facts and estimates used is shown.

  8. Positive-energy D-bar method for acoustic tomography: a computational study

    NASA Astrophysics Data System (ADS)

    de Hoop, M. V.; Lassas, M.; Santacesaria, M.; Siltanen, S.; Tamminen, J. P.

    2016-02-01

    A new computational method for reconstructing a potential from the Dirichlet-to-Neumann (DN) map at positive energy is developed. The method is based on D-bar techniques and it works in absence of exceptional points—in particular, if the potential is small enough compared to the energy. Numerical tests reveal exceptional points for perturbed, radial potentials. Reconstructions for several potentials are computed using simulated DN maps with and without added noise. The new reconstruction method is shown to work well for energy values between 10-5 and 5, smaller values giving better results.

  9. Complications of chronic sinusitis on orbital sonography and craniofacial computed tomography--a case report.

    PubMed

    Osuagwu, Y U; Agunloye, A M; Adeyinka, A O; Obajimi, M O

    2011-06-01

    A 15-year-old boy without a previous history of sinusitis presented with life threatening complications from chronic pansinusitis. This report highlights the role of ultrasound and computed tomography (CT) in the diagnosis and management of occult sinusitis and its complications. PMID:22195387

  10. Comparison of Swedish and Norwegian Use of Cone-Beam Computed Tomography: a Questionnaire Study

    PubMed Central

    Strindberg, Jerker Edén; Hol, Caroline; Torgersen, Gerald; Møystad, Anne; Nilsson, Mats; Hellén-Halme, Kristina

    2015-01-01

    ABSTRACT Objectives Cone-beam computed tomography in dentistry can be used in some countries by other dentists than specialists in radiology. The frequency of buying cone-beam computed tomography to examine patients is rapidly growing, thus knowledge of how to use it is very important. The aim was to compare the outcome of an investigation on the use of cone-beam computed tomography in Sweden with a previous Norwegian study, regarding specifically technical aspects. Material and Methods The questionnaire contained 45 questions, including 35 comparable questions to Norwegian clinics one year previous. Results were based on inter-comparison of the outcome from each of the two questionnaire studies. Results Responses rate was 71% in Sweden. There, most of cone-beam computed tomography (CBCT) examinations performed by dental nurses, while in Norway by specialists. More than two-thirds of the CBCT units had a scout image function, regularly used in both Sweden (79%) and Norway (75%). In Sweden 4% and in Norway 41% of the respondents did not wait for the report from the radiographic specialist before initiating treatment. Conclusions The bilateral comparison showed an overall similarity between the two countries. The survey gave explicit and important knowledge of the need for education and training of the whole team, since radiation dose to the patient could vary a lot for the same kind of radiographic examination. It is essential to establish quality assurance protocols with defined responsibilities in the team in order to maintain high diagnostic accuracy for all examinations when using cone-beam computed tomography for patient examinations. PMID:26904179

  11. Virtual tomography: a new approach to efficient human-computer interaction for medical imaging

    NASA Astrophysics Data System (ADS)

    Teistler, Michael; Bott, Oliver J.; Dormeier, Jochen; Pretschner, Dietrich P.

    2003-05-01

    By utilizing virtual reality (VR) technologies the computer system virtusMED implements the concept of virtual tomography for exploring medical volumetric image data. Photographic data from a virtual patient as well as CT or MRI data from real patients are visualized within a virtual scene. The view of this scene is determined either by a conventional computer mouse, a head-mounted display or a freely movable flat panel. A virtual examination probe is used to generate oblique tomographic images which are computed from the given volume data. In addition, virtual models can be integrated into the scene such as anatomical models of bones and inner organs. virtusMED has shown to be a valuable tool to learn human anaotomy and to udnerstand the principles of medical imaging such as sonography. Furthermore its utilization to improve CT and MRI based diagnosis is very promising. Compared to VR systems of the past, the standard PC-based system virtusMED is a cost-efficient and easily maintained solution providing a highly intuitive time-saving user interface for medical imaging.

  12. Screening for lung cancer with low-dose computed tomography: a review of current status

    PubMed Central

    Bowman, Rayleen V.; Yang, Ian A.; Fong, Kwun M.; Berg, Christine D.

    2013-01-01

    Screening using low-dose computed tomography (CT) represents an exciting new development in the struggle to improve outcomes for people with lung cancer. Randomised controlled evidence demonstrating a 20% relative lung cancer mortality benefit has led to endorsement of screening by several expert bodies in the US and funding by healthcare providers. Despite this pivotal result, many questions remain regarding technical and logistical aspects of screening, cost-effectiveness and generalizability to other settings. This review discusses the rationale behind screening, the results of on-going trials, potential harms of screening and current knowledge gaps. PMID:24163745

  13. Stimulated dual-band infrared computed tomography: a tool to inspect the aging infrastructure

    NASA Astrophysics Data System (ADS)

    DelGrande, Nancy; Durbin, Philip F.

    1995-09-01

    We have developed stimulated dual-band infrared (IR) computed tomography as a tool to inspect the aging infrastructure. Our system has the potential to locate and quantify structural damage within airframes and bridge decks. Typically, dual-band IR detection methods improve the signal-to-noise ratio by a factor of ten, compared to single-band IR detection methods. We conducted a demonstration at Boeing using a uniform pulsed-heat source to stimulate IR images of hidden defects in the 727 fuselage. Our dual-band IR camera and image processing system produced temperature, thermal inertia, and cooling-rate maps. In combination, these maps characterized the defect site, size, depth, thickness, and type. We quantified the percent metal loss from corrosion above a threshold of 5%, with overall uncertainties of 3%. Also, we conducted a feasibility study of dual-band IR thermal imaging for bridge deck inspections. We determined the sites and relative concrete displacement of 12- in. and 4-in. deep delaminations from thin styrofoam implants in asphalt-covered concrete slabs. We demonstrated the value of dual-band IR computed tomography to quantify structural damage within flash-heated airframes and naturally heated bridge decks.

  14. Stimulated dual-band infrared computed tomography: A tool to inspect the aging infrastructure

    SciTech Connect

    Del Grande, N.K.; Durbin, P.F.

    1995-06-27

    The authors have developed stimulated dual-band infrared (IR) computed tomography as a tool to inspect the aging infrastructure. The system has the potential to locate and quantify structural damage within airframes and bridge decks. Typically, dual-band IR detection methods improve the signal-to-noise ratio by a factor of ten, compared to single-band IR detection methods. They conducted a demonstration at Boeing using a uniform pulsed-heat source to stimulate IR images of hidden defects in the 727 fuselage. The dual-band IR camera and image processing system produced temperature, thermal inertia, and cooling-rate maps. In combination, these maps characterized the defect site, size, depth, thickness and type. The authors quantified the percent metal loss from corrosion above a threshold of 5%, with overall uncertainties of 3%. Also, they conducted a feasibility study of dual-band IR thermal imaging for bridge deck inspections. They determined the sites and relative concrete displacement of 2-in. and 4-in. deep delaminations from thin styrofoam implants in asphalt-covered concrete slabs. They demonstrated the value of dual-band IR computed tomography to quantify structural damage within flash-heated airframes and naturally-heated bridge decks.

  15. Radiation doses in cone-beam breast computed tomography: A Monte Carlo simulation study

    SciTech Connect

    Yi Ying; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Shen Youtao; Liu Xinming; Ge Shuaiping; You Zhicheng; Wang Tianpeng; Shaw, Chris C.

    2011-02-15

    Purpose: In this article, we describe a method to estimate the spatial dose variation, average dose and mean glandular dose (MGD) for a real breast using Monte Carlo simulation based on cone beam breast computed tomography (CBBCT) images. We present and discuss the dose estimation results for 19 mastectomy breast specimens, 4 homogeneous breast models, 6 ellipsoidal phantoms, and 6 cylindrical phantoms. Methods: To validate the Monte Carlo method for dose estimation in CBBCT, we compared the Monte Carlo dose estimates with the thermoluminescent dosimeter measurements at various radial positions in two polycarbonate cylinders (11- and 15-cm in diameter). Cone-beam computed tomography (CBCT) images of 19 mastectomy breast specimens, obtained with a bench-top experimental scanner, were segmented and used to construct 19 structured breast models. Monte Carlo simulation of CBBCT with these models was performed and used to estimate the point doses, average doses, and mean glandular doses for unit open air exposure at the iso-center. Mass based glandularity values were computed and used to investigate their effects on the average doses as well as the mean glandular doses. Average doses for 4 homogeneous breast models were estimated and compared to those of the corresponding structured breast models to investigate the effect of tissue structures. Average doses for ellipsoidal and cylindrical digital phantoms of identical diameter and height were also estimated for various glandularity values and compared with those for the structured breast models. Results: The absorbed dose maps for structured breast models show that doses in the glandular tissue were higher than those in the nearby adipose tissue. Estimated average doses for the homogeneous breast models were almost identical to those for the structured breast models (p=1). Normalized average doses estimated for the ellipsoidal phantoms were similar to those for the structured breast models (root mean square (rms

  16. Cardiac findings on non-gated chest computed tomography: A clinical and pictorial review.

    PubMed

    Kanza, Rene Epunza; Allard, Christian; Berube, Michel

    2016-02-01

    The use of chest computed tomography (CT) as an imaging test for the evaluation of thoracic pathology has significantly increased during the last four decades. Although cardiopulmonary diseases often overlap in their clinical manifestation, radiologists tend to overlook the heart while interpreting routine chest CT. Recent advances in CT technology have led to significant reduction of heart motion artefacts and now allow for the identification of several cardiac findings on chest CT even without electrocardiogram (ECG) gating. These observations range from simple curiosity to both benign and malignant discoveries, to life-threatening discoveries. We here present a clinical and radiologic review of common and less common cardiac findings discovered on non-gated chest CT in order to draw the attention of radiologists and referring physicians to these possibilities. PMID:26781150

  17. Head trauma evaluated by magnetic resonance and computed tomography: a comparison

    SciTech Connect

    Han, J.G.; Kaufman, B.; Alfidi, R.J.

    1984-01-01

    Magnetic resonance (MR) images and computed tomograms of 25 patients with head trauma were compared. MR proved to be superior in many ways for demonstrating extracerebral as well as intracerebral traumatic lesions. Isodense subdural hemotomas, which present a diagnostic dilemma on CT images were clearly seen on MR, regardless of their varying CT densities. In a case of epidural hematoma, the dura mater was shown directly as nearly devoid of signal on MR. Direct coronal images provided excellent visualization of extracerebral collections along the peritentorial space and subtemporal area. In a patient with intracerebral hematoma CT failed to demonstrate residual parenchymal changes in a 3-month follow-up study, but MR clearly depicted the abnormalities. The superiority of MR over CT was also well illustrated in a patient with post-traumatic osteomyelitis of the calvarium.

  18. Rare appearance of an odontogenic myxoma in cone-beam computed tomography: a case report

    PubMed Central

    Dabbaghi, Arash; Nikkerdar, Nafiseh; Bayati, Soheyla; Golshah, Amin

    2016-01-01

    Odontogenic myxoma (OM) is an infiltrative benign bone tumor that occurs almost exclusively in the facial skeleton. The radiographic characteristics of odontogenic myxoma may produce several patterns, making diagnosis difficult. Cone-beam computed tomography (CBCT) may prove extremely useful in clarifying the intraosseous extent of the tumor and its effects on surrounding structures. Here, we report a case of odontogenic myxoma of the mandible in a 27-year-old female. The patient exhibited a slight swelling in the left mandible. Surgical resection was performed. No recurrence was noted. In the CBCT sections, we observed perforation of the cortical plate and radiopaque line that extended from the periosteum, resembling "sunray" appearance—a rare feature of OM—which could not be assessed by panoramic radiography. PMID:27092217

  19. Rare appearance of an odontogenic myxoma in cone-beam computed tomography: a case report.

    PubMed

    Dabbaghi, Arash; Nikkerdar, Nafiseh; Bayati, Soheyla; Golshah, Amin

    2016-01-01

    Odontogenic myxoma (OM) is an infiltrative benign bone tumor that occurs almost exclusively in the facial skeleton. The radiographic characteristics of odontogenic myxoma may produce several patterns, making diagnosis difficult. Cone-beam computed tomography (CBCT) may prove extremely useful in clarifying the intraosseous extent of the tumor and its effects on surrounding structures. Here, we report a case of odontogenic myxoma of the mandible in a 27-year-old female. The patient exhibited a slight swelling in the left mandible. Surgical resection was performed. No recurrence was noted. In the CBCT sections, we observed perforation of the cortical plate and radiopaque line that extended from the periosteum, resembling "sunray" appearance-a rare feature of OM-which could not be assessed by panoramic radiography. PMID:27092217

  20. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    SciTech Connect

    Ding Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-06-15

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of -11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis.

  1. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    PubMed Central

    Ding, Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-01-01

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of −11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis. PMID:23718593

  2. Image-Guided Drug Delivery with Single-Photon Emission Computed Tomography: A Review of Literature

    PubMed Central

    Chakravarty, Rubel; Hong, Hao; Cai, Weibo

    2014-01-01

    Tremendous resources are being invested all over the world for prevention, diagnosis, and treatment of various types of cancer. Successful cancer management depends on accurate diagnosis of the disease along with precise therapeutic protocol. The conventional systemic drug delivery approaches generally cannot completely remove the competent cancer cells without surpassing the toxicity limits to normal tissues. Therefore, development of efficient drug delivery systems holds prime importance in medicine and healthcare. Also, molecular imaging can play an increasingly important and revolutionizing role in disease management. Synergistic use of molecular imaging and targeted drug delivery approaches provides unique opportunities in a relatively new area called `image-guided drug delivery' (IGDD). Single-photon emission computed tomography (SPECT) is the most widely used nuclear imaging modality in clinical context and is increasingly being used to guide targeted therapeutics. The innovations in material science have fueled the development of efficient drug carriers based on, polymers, liposomes, micelles, dendrimers, microparticles, nanoparticles, etc. Efficient utilization of these drug carriers along with SPECT imaging technology have the potential to transform patient care by personalizing therapy to the individual patient, lessening the invasiveness of conventional treatment procedures and rapidly monitoring the therapeutic efficacy. SPECT-IGDD is not only effective for treatment of cancer but might also find utility in management of several other diseases. Herein, we provide a concise overview of the latest advances in SPECT-IGDD procedures and discuss the challenges and opportunities for advancement of the field. PMID:25182469

  3. Assessment of Mandibular Distraction Regenerate Using Ultrasonography and Cone Beam Computed Tomography: A Clinical Study.

    PubMed

    Dabas, Jitender; Mohanty, Sujata; Chaudhary, Zainab; Rani, Amita

    2016-03-01

    Distraction osteogenesis (DO) is becoming a popular method of reconstruction for maxillofacial bony deformities or defects secondary to trauma or surgical tumor ablation. However, the technique is very sensitive in terms of the rate and rhythm of distraction. Because of this, there is a need for monitoring of the distraction regenerate during the distraction as well as the consolidation period. The present study was conducted to assess the regenerate using two imaging modalities, namely, ultrasonography (USG) and cone beam computed tomography (CBCT) to determine their relative efficacies and to weigh their clinical usefulness in assessment of DO regenerate. The study was conducted on 12 patients (18 sites) who underwent mandibular distraction for correction of facial deformities. The results showed that overall USG correlated better with the condition of regenerate (r = 0.606) as compared with CBCT (r = 0.476). However, USG was less effective as compared with CBCT in assessing the regenerate once corticomedullary differentiation occurred in the bone. PMID:26889351

  4. Investigation of the adjoint-state method for ultrasound computed tomography: a numerical and experimental study

    NASA Astrophysics Data System (ADS)

    Anis, Fatima; Lou, Yang; Conjusteau, André; Su, Richard; Oruganti, Tanmayi; Ermilov, Sergey A.; Oraevsky, Alexander A.; Anastasio, Mark A.

    2014-03-01

    In this work, we investigate a novel reconstruction method for laser-induced ultrasound computed tomography (USCT) breast imaging that circumvents limitations of existing methods that rely on ray-tracing. There is currently great interest in developing hybrid imaging systems that combine optoacoustic tomography (OAT) and USCT. There are two primary motivations for this: (1) the speed-of-sound (SOS) distribution reconstructed by USCT can provide complementary diagnostic information; and (2) the reconstructed SOS distribution can be incorporated in the OAT reconstruction algorithm to improve OAT image quality. However, image reconstruction in USCT remains challenging. The majority of existing approaches for USCT breast imaging involve ray-tracing to establish the imaging operator. This process is cumbersome and can lead to inaccuracies in the reconstructed SOS images in the presence of multiple ray-paths and/or shadow zones. To circumvent these problems, we implemented a partial differential equation-based Eulerian approach to USCT that was proposed in the mathematics literature but never investigated for medical imaging applications. This method operates by directly inverting the Eikonal equation without ray-tracing. A numerical implementation of this method was developed and compared to existing reconstruction methods for USCT breast imaging. We demonstrated the ability of the new method to reconstruct SOS maps from TOF data obtained by a hybrid OAT/USCT imager built by our team.

  5. Three-dimensional maxillary and mandibular regional superimposition using cone beam computed tomography: a validation study.

    PubMed

    Koerich, L; Burns, D; Weissheimer, A; Claus, J D P

    2016-05-01

    This study aimed to validate a novel method for fast regional superimposition of cone beam computed tomography (CBCT) scans. The method can be used with smaller field of view scans, thereby allowing for a lower radiation dose. This retrospective study used two dry skulls and secondary data from 15 patients who had more than one scan taken using the same machine. Two observers tested two types of regional voxel-based superimposition: maxillary and mandibular. The registration took 10-15s. Three-dimensional surface models of the maxillas and mandibles were generated via standardized threshold segmentation, and the accuracy and reproducibility of the superimpositions were assessed using the iterative closest point technique to measure the root mean square (RMS) distance between the images. Five areas were measured and a RMS≤0.25 was considered successful. Descriptive statistics and the intra-class correlation coefficient (ICC) were used to compare the intra-observer measurement reproducibility. The ICC was ≥0.980 for all of the variables and the highest RMS found was 0.241. The inter-observer reproducibility was assessed case by case and was perfect (RMS 0) for 68% (23 out of 34) of the superimpositions done and not clinically significant (RMS≤0.25) for the other 32%. The method is fast, accurate, and reproducible and is an alternative to cranial base superimposition. PMID:26794399

  6. Relevant incidental findings at abdominal multi-detector contrast-enhanced computed tomography: A collateral screening?

    PubMed Central

    Sconfienza, Luca Maria; Mauri, Giovanni; Muzzupappa, Claudia; Poloni, Alessandro; Bandirali, Michele; Esseridou, Anastassia; Tritella, Stefania; Secchi, Francesco; Di Leo, Giovanni; Sardanelli, Francesco

    2015-01-01

    AIM: To investigate the prevalence of relevant incidental findings (RIFs) detected during routine abdominal contrast-enhanced computed tomography (CeCT). METHODS: We retrospectively evaluated the reports of a consecutive series of abdominal CeCT studies performed between January and May 2013. For each report, patients’ age and sex, admission as inpatient or outpatient, clinical suspicion as indicated by the requesting physician, availability of a previous abdominal examination, and name of the reporting radiologist were recorded. Based on the clinical suspicion, the presence and features of any RIFs (if needing additional workup) was noted. RESULTS: One thousand forty abdominal CeCT were performed in 949 patients (528 males, mean age 66 ± 14 years). No significant difference was found between inpatients and outpatients age and sex distribution (P > 0.472). RIFs were found in 195/1040 (18.8%) CeCT [inpatients = 108/470 (23.0%); outpatients = 87/570 (15.2%); P = 0.002]. RIFs were found in 30/440 (6.8%) CeCT with a previous exam and in 165/600 (27.5%) without a previous exam (P < 0.001). Radiologists’ distribution between inpatients or outpatients was significantly different (P < 0.001). RIFs prevalence increased with aging, except for a peak in 40-49 year group. Most involved organs were kidneys, gallbladder, and lungs. CONCLUSION: A RIF is detected in 1/5 patients undergoing abdominal CeCT. Risk of overdiagnosis should be taken into account. PMID:26516432

  7. Clinical significance of visceral adiposity assessed by computed tomography: A Japanese perspective

    PubMed Central

    Ryo, Miwa; Kishida, Ken; Nakamura, Tadashi; Yoshizumi, Tohru; Funahashi, Tohru; Shimomura, Iichiro

    2014-01-01

    Abdominal obesity, rather than total amount of fat, is linked to obesity-related disorders. Visceral adiposity is an important component of obesity-related disorders in Japanese individuals with a mild degree of adiposity compared with Western subjects. In 1983, our group reported techniques for body fat analysis using computed tomography (CT) and established the concept of visceral fat obesity in which intra-abdominal fat accumulation is an important factor in the development of obesity-related complications, such as diabetes, lipid disorders, hypertension and atherosclerosis. Our group also established ideal imaging conditions for determining abdominal fat area at the umbilical level CT scan. Visceral fat area (VFA) measured in a single slice at L4 level correlated significantly with the total abdominal visceral fat volume measured on multislice CT scan. In a large-scale study of a Japanese population, the mean number of obesity-related cardiovascular risk factors (hypertension, low high-density lipoprotein cholesterolemia and/or hypertriglyceridemia, and hyperglycemia) was greater than 1.0 at 100 cm2 of VFA, irrespective of gender, age and body mass index. Our group also demonstrated that reduction of visceral fat accumulation subsequent to voluntary lifestyle modification, “Hokenshido”, correlated with a decrease in the number of obesity-related cardiovascular risk factors. It is important to select the most appropriate subjects from the general population (e.g., non-obese subjects with a cluster of risk factors for the metabolic syndrome) that are most suitable for body weight reduction, with the goal of preventing atherosclerotic cardiovascular diseases. PMID:25071881

  8. Puffed-cheek computed tomography: a dynamic maneuver for imaging oral cavity tumors.

    PubMed

    Erdogan, Nezahat; Bulbul, Erdogan; Songu, Murat; Uluc, Engin; Onal, Kazim; Apaydin, Melda; Katilmis, Huseyin

    2012-09-01

    We conducted a prospective study to compare the effectiveness of conventional computed tomography (CT) and puffed-cheek CT in detecting the presence and extension of oral cavity malignant tumors. We enrolled 11 patients--5 men and 6 women, aged 32 to 85 years--who had a primary squamous cell carcinoma of the oral cavity. These tumors were located in the floor of the mouth in 4 patients, in the buccal mucosa in 4, in both the buccal mucosa and retromolar trigone in 2, and in the retromolar trigone only in 1. First, conventional contrast-enhanced axial CT was obtained through the oral cavity and neck in each patient. Next, axial imaging was obtained through the oral cavity while patients inflated their cheeks, pursed their lips, and held their breath. We found that the puffed-cheek CTs provided more information regarding the size and extent of the squamous cell carcinomas than did the conventional CTs. For example, in 8 patients, conventional CT could not differentiate the tumor from the normal mucosal surface, but puffed-cheek images clearly showed the surface of the tumor as distinct from the normal mucosa. More disconcerting was the fact that in the other 3 patients, conventional CTs were evaluated as normal, even though puffed-cheek imaging clearly showed the mass in each case. We conclude that puffed-cheek CT is superior to conventional CT for evaluating the mucosal surfaces of the oral cavity. It provides a clearer and more detailed picture with no downside. PMID:22996710

  9. Quantifying Heterogeneity in Emphysema from High Resolution Computed Tomography: A Lung Tissue Research Consortium Study

    PubMed Central

    Yilmaz, Cuneyt; Dane, Dan M.; Patel, Nova C.; Hsia, Connie C.W.

    2012-01-01

    Rationale and Objective To quantify spatial distribution of emphysema using high-resolution computed tomography (HRCT), we applied semi-automated analysis with internal attenuation calibration to measure regional air volume, tissue volume, and fractional tissue volume (FTV=tissue/[air+tissue] volume) in well-characterized patients studied by the Lung Tissue Research Consortium (LTRC). Methods HRCT was obtained at supine end-inspiration and end-expiration, and prone end-inspiration from 31 patients with mild, moderate, severe, or very severe emphysema (stages II–V, FEV1>75%, 51–75%, 21–50% and ≤20% predicted, respectively). Control data were from 20 healthy non-smokers (stage I). Each lobe was analyzed separately. Heterogeneity of FTV was assessed from coefficients of variation (CV) within and among lobes, and the kurtosis and skewness of FTV histograms. Results In emphysema, lobar air volume increased up to 177% except in the right middle lobe. Lobar tissue volume increased up to 107% in mild-moderate stages then normalized in advanced stages. Normally, FTV was up to 82% higher in lower than upper lobes. In mild-moderate emphysema, lobar FTV increased by up to 74% above normal at supine inspiration. In severe emphysema FTV declined below normal in all lobes and positions in correlation with pulmonary function (p<0.05). Markers of FTV heterogeneity increased steadily with disease stage in correlation with pulmonary function (p<0.05); the pattern is distinct from that seen in interstitial lung disease (ILD). Conclusion CT-derived biomarkers differentiate the spatial patterns of emphysema distribution and heterogeneity from that in ILD. Early emphysema is associated with elevated tissue volume and FTV, consistent with hyperemia, inflammation or atelectasis. PMID:23122057

  10. Segmentation and quantification of materials with energy discriminating computed tomography: A phantom study

    SciTech Connect

    Le, Huy Q.; Molloi, Sabee

    2011-01-15

    Purpose: To experimentally investigate whether a computed tomography (CT) system based on CdZnTe (CZT) detectors in conjunction with a least-squares parameter estimation technique can be used to decompose four different materials. Methods: The material decomposition process was divided into a segmentation task and a quantification task. A least-squares minimization algorithm was used to decompose materials with five measurements of the energy dependent linear attenuation coefficients. A small field-of-view energy discriminating CT system was built. The CT system consisted of an x-ray tube, a rotational stage, and an array of CZT detectors. The CZT array was composed of 64 pixels, each of which is 0.8x0.8x3 mm. Images were acquired at 80 kVp in fluoroscopic mode at 50 ms per frame. The detector resolved the x-ray spectrum into energy bins of 22-32, 33-39, 40-46, 47-56, and 57-80 keV. Four phantoms were constructed from polymethylmethacrylate (PMMA), polyethylene, polyoxymethylene, hydroxyapatite, and iodine. Three phantoms were composed of three materials with embedded hydroxyapatite (50, 150, 250, and 350 mg/ml) and iodine (4, 8, 12, and 16 mg/ml) contrast elements. One phantom was composed of four materials with embedded hydroxyapatite (150 and 350 mg/ml) and iodine (8 and 16 mg/ml). Calibrations consisted of PMMA phantoms with either hydroxyapatite (100, 200, 300, 400, and 500 mg/ml) or iodine (5, 15, 25, 35, and 45 mg/ml) embedded. Filtered backprojection and a ramp filter were used to reconstruct images from each energy bin. Material segmentation and quantification were performed and compared between different phantoms. Results: All phantoms were decomposed accurately, but some voxels in the base material regions were incorrectly identified. Average quantification errors of hydroxyapatite/iodine were 9.26/7.13%, 7.73/5.58%, and 12.93/8.23% for the three-material PMMA, polyethylene, and polyoxymethylene phantoms, respectively. The average errors for the four

  11. Preliminary Phase Field Computational Model Development

    SciTech Connect

    Li, Yulan; Hu, Shenyang Y.; Xu, Ke; Suter, Jonathan D.; McCloy, John S.; Johnson, Bradley R.; Ramuhalli, Pradeep

    2014-12-15

    This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in

  12. Computing and information sciences preliminary engineering design study

    SciTech Connect

    Schroeder, J O; Pearson, E W; Thomas, J J; Brothers, J W; Campbell, W K; DeVaney, D M; Jones, D R; Littlefield, R J; Peterson, M J

    1991-04-01

    This document presents the preliminary design concept for the integrated computing and information system to be included in the Environmental and Molecular Sciences Laboratory (EMSL) at the Pacific Northwest Laboratory, Richland, Washington, for the US Department of Energy (DOE). The EMSL is scheduled for completion and occupancy in 1994 or 1995 and will support the DOE environmental mission, in particular hazardous waste remediation. The focus of the report is on the Computing and Information Sciences engineering task of providing a fully integrated state-of-the-art computing environment for simulation, experimentation and analysis in support of molecular research. The EMSL will house two major research organizations, the Molecular Sciences Research Center (MSRC) and part of the Environmental Sciences Research Center (ESRC). Included in the report is a preliminary description of the computing and information system to be included. The proposed system architecture is based on a preliminary understanding of the EMSL users' needs for computational resources. As users understand more about the scientific challenges they face, the definition of the functional requirements will change. At the same time, the engineering team will be gaining experience with new computing technologies. Accordingly, the design architecture must evolve to reflect this new understanding of functional requirements and enabling technologies. 3 figs., 2 tabs.

  13. Modeling the complete Otto cycle: Preliminary version. [computer programming

    NASA Technical Reports Server (NTRS)

    Zeleznik, F. J.; Mcbride, B. J.

    1977-01-01

    A description is given of the equations and the computer program being developed to model the complete Otto cycle. The program incorporates such important features as: (1) heat transfer, (2) finite combustion rates, (3) complete chemical kinetics in the burned gas, (4) exhaust gas recirculation, and (5) manifold vacuum or supercharging. Changes in thermodynamic, kinetic and transport data as well as model parameters can be made without reprogramming. Preliminary calculations indicate that: (1) chemistry and heat transfer significantly affect composition and performance, (2) there seems to be a strong interaction among model parameters, and (3) a number of cycles must be calculated in order to obtain steady-state conditions.

  14. Endodontic management of a fused mandibular second molar and paramolar with the aid of spiral computed tomography: a case report.

    PubMed

    Ballal, Suma; Sachdeva, Gurmeet Singh; Kandaswamy, Deivanayagam

    2007-10-01

    Fusion and gemination are developmental anomalies of the dental hard tissues that might require endodontic and surgical treatment for functional, orthodontic, or esthetic reasons. In this article, we report a rare case of successful endodontic management of unilateral fused mandibular second molar with a paramolar. The rarity with which this entity appears, along with its complex characteristics, often makes it difficult to diagnose and treat. The use of high-end diagnostic imaging modalities such as spiral computed tomography can help the clinician in making a confirmatory diagnosis and determining the treatment plan before undertaking the actual treatment. This case report highlights the usefulness of spiral computed tomography in accurate diagnosis and endodontic management of these unusual cases. PMID:17889700

  15. Diagnosis of simulated condylar bone defects using panoramic radiography, spiral tomography and cone-beam computed tomography: A comparison study

    PubMed Central

    Salemi, Fatemeh; Shokri, Abbas; Baharvand, Maryam

    2015-01-01

    Objectives: Radiographic examination is one of the most important parts of the clinical assessment routine for temporomandibular disorders. The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography(CBCT) with panoramic radiography and spiral computed tomography for the detection of the simulated mandibular condyle bone lesions. Study Design: The sample consisted of 10 TMJs from 5 dried human skulls. Simulated erosive and osteophytic lesions were created in 3 different sizes using round diamond bur and bone chips, respectively. Panoramic radiography, spiral tomography and cone-beam computed tomography were used in defect detection. Data were statistically analyzed with the Mann-Whitney test. The reliability and degrees of agreement between two observers were also determined by the mean of Cohen’s Kappa analysis. Results: CBCT had a statistically significant superiority than other studied techniques in detection of both erosive and osteophytic lesions with different sizes. There were significant differences between tomography and panoramic in correct detection of both erosive and osteophytic lesions with 1mm and 1.5 mm in size. However, there were no significant differences between Tomography and Panoramic in correct detection of both erosive and osteophytic lesions with 0.5 mm in size. Conclusions: CBCT images provide a greater diagnostic accuracy than spiral tomography and panoramic radiography in the detection of condylar bone erosions and osteophytes. Key words:Bone defect, Condyle, CBCT, Panoramic, radiography. PMID:25810839

  16. Emission Computed Tomography: A New Technique for the Quantitative Physiologic Study of Brain and Heart in Vivo

    DOE R&D Accomplishments Database

    Phelps, M. E.; Hoffman, E. J.; Huang, S. C.; Schelbert, H. R.; Kuhl, D. E.

    1978-01-01

    Emission computed tomography can provide a quantitative in vivo measurement of regional tissue radionuclide tracer concentrations. This facility when combined with physiologic models and radioactively labeled physiologic tracers that behave in a predictable manner allow measurement of a wide variety of physiologic variables. This integrated technique has been referred to as Physiologic Tomography (PT). PT requires labeled compounds which trace physiologic processes in a known and predictable manner, and physiologic models which are appropriately formulated and validated to derive physiologic variables from ECT data. In order to effectively achieve this goal, PT requires an ECT system that is capable of performing truly quantitative or analytical measurements of tissue tracer concentrations and which has been well characterized in terms of spatial resolution, sensitivity and signal to noise ratios in the tomographic image. This paper illustrates the capabilities of emission computed tomography and provides examples of physiologic tomography for the regional measurement of cerebral and myocardial metabolic rate for glucose, regional measurement of cerebral blood volume, gated cardiac blood pools and capillary perfusion in brain and heart. Studies on patients with stroke and myocardial ischemia are also presented.

  17. Measurement of the Interantral Bone in Implant Dentistry Using Panoramic Radiography and Cone Beam Computed Tomography: A Human Radiographic Study

    PubMed Central

    Kopecka, D; Simunek, A; Streblov, J; Slezak, R; Capek, L

    2014-01-01

    ABSTRACT Objective: To analyse the dimensions of interantral bone available for dental implant placement in the fully edentulous maxilla. Methods: Interantral bone height (IBH) was measured using panoramic radiography and computed tomography (CT). Interantral bone width (IBW) was measured by means of CT. Results: The difference between both imaging methods in IBH assessment was highly statistically significant (p < 0.001) in the canine area, whereas in other areas, it was found to not be significant. Measured in the CT scans, bone is significantly higher in the canine area compared to the area of central and lateral incisors (p < 0.001). Significant variations in IBW were found in all three locations: bone in the central incisor area is the widest, in the area of the lateral incisor, the narrowest (p < 0.001). Conclusion: Panoramic radiography is a sufficiently accurate method for IBH imaging in the incisor area, but not in the canine area. PMID:25781290

  18. Clival lesion incidentally discovered on cone-beam computed tomography: A case report and review of the literature

    PubMed Central

    Tadinada, Aditya; Rengasamy, Kandasamy; Fellows, Douglas; Lurie, Alan G.

    2014-01-01

    An osteolytic lesion with a small central area of mineralization and sclerotic borders was discovered incidentally in the clivus on the cone-beam computed tomography (CBCT) of a 27-year-old male patient. This benign appearance indicated a primary differential diagnosis of non-aggressive lesions such as fibro-osseous lesions and arrested pneumatization. Further, on magnetic resonance imaging (MRI), the lesion showed a homogenously low T1 signal intensity with mild internal enhancement after post-gadolinium and a heterogeneous T2 signal intensity. These signal characteristics might be attributed to the fibrous tissues, chondroid matrix, calcific material, or cystic component of the lesion; thus, chondroblastoma and chondromyxoid fibroma were added to the differential diagnosis. Although this report was limited by the lack of final diagnosis and the patient lost to follow-up, the incidental skull base finding would be important for interpreting the entire volume of CBCT by a qualified oral and maxillofacial radiologist. PMID:24944968

  19. Verification of In-Treatment Tumor Position Using Kilovoltage Cone-Beam Computed Tomography: A Preliminary Study

    SciTech Connect

    Nakagawa, Keiichi Yamashita, Hideomi; Shiraishi, Kenshiro; Igaki, Hiroshi; Terahara, Atsuro; Nakamura, Naoki; Ohtomo, Kuni; Saegusa, Shigeki R.T.T.; Shiraki, Takashi R.T.T.; Oritate, Takashi R.T.T.; Yoda, Kiyoshi

    2007-11-15

    Three-dimensional tumor position during rotational dose delivery was evaluated by acquiring in-treatment kilovoltage (kV) cone-beam CT (CBCT) to ensure treatment quality. The CBCT projection data of a phantom were acquired during rotational megavoltage (MV) dose delivery up to 6 Gy to evaluate image quality under MV beam irradiation. A lung tumor patient was treated with a total dose of 48 Gy in four fractions, each fraction including seven coplanar and noncoplanar beams, as well as a full-angle rotational beam. Tumor registration was performed between a planning CT image and a CBCT image immediately after patient setup. The patient couch was adjusted according to the registration results, and then the registration was repeated three times: immediately before treatment, during treatment, and immediately after treatment. The phantom image quality of the kV CBCT was not visually degraded up to the rotational MV dose of 6 Gy. Tumor position during rotational dose delivery was verified for the first time using kV CBCT.

  20. Modification of ACSYNT aircraft computer program for preliminary design

    NASA Technical Reports Server (NTRS)

    Biezad, Daniel J.; Rojos-Oviedo, Ruben

    1994-01-01

    This paper presents the development of a computer simulation of agility flight test techniques. Its purpose is to evaluate the agility of aircraft configurations early in the preliminary design phase. The simulation module is integrated into the NASA Ames aircraft synthesis design code. Trade studies using the agility module embedded within the design code to simulate the combat cycle time agility metric are illustrated using a Northrop F-20 aircraft model. Results show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can also compare the agility potential between different configurations and has the capability to optimize agility performance early in the design process.

  1. Glenohumeral joint kinematics measured by intracortical pins, reflective markers, and computed tomography: A novel technique to assess acromiohumeral distance.

    PubMed

    Dal Maso, Fabien; Blache, Yoann; Raison, Maxime; Lundberg, Arne; Begon, Mickaël

    2016-08-01

    Combination of biplane fluoroscopy and CT-scan provides accurate 3D measurement of the acromiohumeral distance (AHD) during dynamic tasks. However, participants performed only two and six trials in previous experiments to respect the recommended radiation exposure per year. Our objective was to propose a technique to assess the AHD in 3D during dynamic tasks without this limitation. The AHD was computed from glenohumeral kinematics obtained using markers fitted to pins drilled into the scapula and the humerus combined with 3D bone geometry obtained using CT-scan. Four participants performed range-of-motion, daily-living, and sports activities. Sixty-six out of 158trials performed by each participant were analyzed. Two participants were not considered due to experimental issues. AHD decreased with arm elevation. Overall, the smallest AHD occurred in abduction (1.1mm (P1) and 1.2mm (P2)). The smallest AHD were 2.4mm (P1) and 3.1mm (P2) during ADL. It was 2.8mm (P1) and 1.1mm (P2) during sports activities. The humeral head greater and lesser tuberosities came the nearest to the acromion. The proposed technique increases the number of trials acquired during one experiment compared to previous. The identification of movements maximizing AHD is possible, which may provide benefits for shoulder rehabilitation. PMID:26263837

  2. Sensitivity analysis for liver iron measurement through neutron stimulated emission computed tomography: a Monte Carlo study in GEANT4

    NASA Astrophysics Data System (ADS)

    Agasthya, G. A.; Harrawood, B. C.; Shah, J. P.; Kapadia, A. J.

    2012-01-01

    Neutron stimulated emission computed tomography (NSECT) is being developed as a non-invasive imaging modality to detect and quantify iron overload in the human liver. NSECT uses gamma photons emitted by the inelastic interaction between monochromatic fast neutrons and iron nuclei in the body to detect and quantify the disease. Previous simulated and physical experiments with phantoms have shown that NSECT has the potential to accurately diagnose iron overload with reasonable levels of radiation dose. In this work, we describe the results of a simulation study conducted to determine the sensitivity of the NSECT system for hepatic iron quantification in patients of different sizes. A GEANT4 simulation of the NSECT system was developed with a human liver and two torso sizes corresponding to small and large patients. The iron concentration in the liver ranged between 0.5 and 20 mg g-1,In this paper all iron concentrations with units mg g-1 refer to wet weight concentrations. corresponding to clinically reported iron levels in iron-overloaded patients. High-purity germanium gamma detectors were simulated to detect the emitted gamma spectra, which were background corrected using suitable water phantoms and analyzed to determine the minimum detectable level (MDL) of iron and the sensitivity of the NSECT system. These analyses indicate that for a small patient (torso major axis = 30 cm) the MDL is 0.5 mg g-1 and sensitivity is ˜13 ± 2 Fe counts/mg/mSv and for a large patient (torso major axis = 40 cm) the values are 1 mg g-1 and ˜5 ± 1 Fe counts/mg/mSv, respectively. The results demonstrate that the MDL for both patient sizes lies within the clinically significant range for human iron overload.

  3. Risk to fragmented DNA in dry, wet, and frozen states from computed tomography: a comparative theoretical study.

    PubMed

    Wanek, Johann; Rühli, Frank Jakobus

    2016-05-01

    Computed tomography represents the gold standard in forensic and palaeopathological diagnosis. However, the X-rays used may affect the DNA quality through fragmentation and loss of genetic information. Previous work showed that the effects of ionizing radiation on dry DNA are non-significant with P < 10(-8), which cannot be detected by means of polymerase chain reaction methods. In the present paper, complete analytical model that characterizes radiation effects on fragmented DNA in dry, wet, and frozen states is described. Simulation of radiation tracks in water phantom cells was performed using the Geant4-DNA toolkit. Cell hits by electrons with energies between 5 and 20 keV were simulated, and the formation of radiolytic products was assessed at a temperature of 298 K. The diffusion coefficient and the mean square displacement of reactive species were calculated by Stokes-Einstein-Smoluchowski relations at 273 K. Finally, DNA fragment damage was estimated using the density distribution of fragments calculated from atomic force microscopy images. The lowest probability of radiation-induced DNA damage was observed for dry state, with a range from 2.5 × 10(-9) to 7.8 × 10(-12) at 298 K, followed by that for frozen state, with a range from 0.9 to 4 × 10(-7) at 273 K. The highest probability of radiation-induced DNA damage was demonstrated for fragmented DNA in wet state with a range from 2 to 9 × 10(-7) at 298 K. These results significantly improve the interpretation of CT imaging in future studies in forensic and palaeopathological science. PMID:26883247

  4. Little impact of tsunami-stricken nuclear accident on awareness of radiation dose of cardiac computed tomography: A questionnaire study

    PubMed Central

    2013-01-01

    Background With the increased use of cardiac computed tomography (CT), radiation dose remains a major issue, although physicians are trying to reduce the substantial risks associated with use of this diagnostic tool. This study was performed to investigate recognition of the level of radiation exposure from cardiac CT and the differences in the level of awareness of radiation before and after the Fukushima nuclear plant accident. Methods We asked 30 physicians who were undergoing training in internal medicine to determine the equivalent doses of radiation for common radiological examinations when a normal chest X-ray is accepted as one unit; questions about the absolute radiation dose of cardiac CT data were also asked. Results According to the results, 86.6% of respondents believed the exposure to be 1 mSv at most, and 93.3% thought that the exposure was less than that of 100 chest X-rays. This finding indicates that their perceptions were far lower than the actual amounts. Even after the occurrence of such a large nuclear disaster in Fukushima, there were no significant differences in the same subjects’ overall awareness of radiation amounts. Conclusions Even after such a major social issue as the Fukushima nuclear accident, the level of awareness of the accurate radiation amount used in 64-channel multidetector CT (MDCT) by clinical physicians who order this test was not satisfactory. Thus, there is a need for the development of effective continuing education programs to improve awareness of radiation from ionizing radiation devices, including cardiac CT, and emphasis on risk-benefit evaluation based on accurate knowledge during medical training. PMID:23631688

  5. Digital characterization and preliminary computer modeling of hydrocarbon bearing sandstone

    NASA Astrophysics Data System (ADS)

    Latief, Fourier Dzar Eljabbar; Haq, Tedy Muslim

    2014-03-01

    With the advancement of three dimensional imaging technologies, especially the μCT scanning systems, we have been able to obtain three-dimensional digital representation of porous rocks in the scale of micrometers. Characterization was then also possible to conduct using computational approach. Hydrocarbon bearing sandstone has become one of interesting objects to analyze in the last decade. In this research, we performed digital characterization of hydrocarbon bearing sandstone reservoir from Sumatra. The sample was digitized using a μCT scanner (Skyscan 1173) which produced series of reconstructed images with the spatial resolution of 15 μm. Using computational approaches, i.e., image processing, image analysis, and simulation of fluid flow inside the rock using Lattice Boltzmann Method, we have been able to obtain the porosity of the sandstone, which is 23.89%, and the permeability, which is 9382 mD. Based on visual inspection, the porosity value, along with the calculated specific surface area, we produce a preliminary computer model of the rock using grain based method. This method employs a reconstruction of grains using the non-spherical model, and a purely random deposition of the grains in a virtual three dimensional cube with the size of 300 × 300 × 300. The model has porosity of 23.96%, and the permeability is 7215 mD. While the error of the porosity is very small (which is only 0.3%), the permeability has error of around 23% from the real sample which is considered very significant. This suggests that the modeling based on porosity and specific surface area is not satisfactory to produce a representative model. However, this work has been a good example of how characterization and modeling of porous rock can be conducted using a non-destructive computational approach.

  6. Estimation of effective doses to adult and pediatric patients from multislice computed tomography: A method based on energy imparted

    SciTech Connect

    Theocharopoulos, Nicholas; Damilakis, John; Perisinakis, Kostas; Tzedakis, Antonis; Karantanas, Apostolos; Gourtsoyiannis, Nicholas

    2006-10-15

    The purpose of this study is to provide a method and required data for the estimation of effective dose (E) values to adult and pediatric patients from computed tomography (CT) scans of the head, chest abdomen, and pelvis, performed on multi-slice scanners. Mean section radiation dose (d{sub m}) to cylindrical water phantoms of varying radius normalized over CT dose index free-in-air (CTDI{sub F}) were calculated for the head and body scanning modes of a multislice scanner with use of Monte Carlo techniques. Patients were modeled as equivalent water phantoms and the energy imparted ({epsilon}) to simulated pediatric and adult patients was calculated on the basis of measured CTDI{sub F} values. Body region specific energy imparted to effective dose conversion coefficients (E/{epsilon}) for adult male and female patients were generated from previous data. Effective doses to patients aged newborn to adult were derived for all available helical and axial beam collimations, taking into account age specific patient mass and scanning length. Depending on high voltage, body region, and patient sex, E/{epsilon} values ranged from 0.008 mSv/mJ for head scans to 0.024 mSv/mJ for chest scans. When scanned with the same technique factors as the adults, pediatric patients absorb as little as 5% of the energy imparted to adults, but corresponding effective dose values are up to a factor of 1.6 higher. On average, pediatric patients absorb 44% less energy per examination but have a 24% higher effective dose, compared with adults. In clinical practice, effective dose values to pediatric patients are 2.5 to 10 times lower than in adults due to the adaptation of tube current. A method is provided for the calculation of effective dose to adult and pediatric patients on the basis of individual patient characteristics such as sex, mass, dimensions, and density of imaged anatomy, and the technical features of modern multislice scanners. It allows the optimum selection of scanning

  7. PASS: A computer program for Preliminary Aircraft Structural Synthesis

    NASA Technical Reports Server (NTRS)

    Johnson, E. H.

    1977-01-01

    A computer code for Preliminary Aircraft Structural Synthesis provides rapid and accurate analysis for aircraft structures that can be adequately modeled by beam finite elements. The philosophy used in developing the program was to provide a basic framework that can be used for structural synthesis. It is anticipated that a user will need to add detail to this framework in order to perform his specific task. With this philosophy in mind, the program was written so that it is easily divided into segments, thereby making it readily adaptable. The theoretical portion of this manual describes the basic structure of the program and details the development of the unique beam element that is used. The present capability of the algorithm is stated and suggestions are made regarding enhancements to this capability. User information is also given that provides an overview of the program's construction, identifies the required inputs, describes the program output, provides some comments on the program use, and exhibits results for a simple example.

  8. Perforated duodenal ulcer presenting with a subphrenic abscess revealed by plain abdominal X-ray films and confirmed by multi-detector computed tomography: a case report

    PubMed Central

    2013-01-01

    Introduction Peptic ulcer disease is still the major cause of gastrointestinal perforation despite major improvements in both diagnostic and therapeutic strategies. While the diagnosis of a perforated ulcer is straightforward in typical cases, its clinical onset may be subtle because of comorbidities and/or concurrent therapies. Case presentation We report the case of a 53-year-old Caucasian man with a history of chronic myeloid leukemia on maintenance therapy (100mg/day) with imatinib who was found to have a subphrenic abscess resulting from a perforated duodenal ulcer that had been clinically overlooked. Our patient was febrile (38.5°C) with abdominal tenderness and hypoactive bowel sounds. On the abdominal plain X-ray films, a right subphrenic abscess could be seen. On contrast-enhanced multi-detector computed tomography, a huge air-fluid collection extending from the subphrenic to the subhepatic anterior space was observed. After oral administration of 500cm3 of 3 percent diluted diatrizoate meglumine, an extraluminal leakage of the water-soluble iodinated contrast media could then be appreciated as a result of a perforated duodenal ulcer. During surgery, the abscess was drained and extensive adhesiolysis had to be performed to expose the duodenal bulb where the ulcer was first identified by methylene blue administration and then sutured. Conclusions While subphrenic abscesses are well known complications of perforated gastric or duodenal ulcers, they have nowadays become rare thanks to advances in both diagnostic and therapeutic strategies for peptic ulcer disease. However, when peptic ulcer disease is not clinically suspected, the contribution of imaging may be substantial. PMID:24215711

  9. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... computed on preliminary term basis. 1.818-4 Section 1.818-4 Internal Revenue INTERNAL REVENUE SERVICE... Provisions § 1.818-4 Election with respect to life insurance reserves computed on preliminary term basis. (a... the life insurance reserves are computed on one of the recognized preliminary term bases to elect...

  10. Preliminary performance assessment of computer automated facial approximations using computed tomography scans of living individuals.

    PubMed

    Parks, Connie L; Richard, Adam H; Monson, Keith L

    2013-12-10

    ReFace (Reality Enhancement Facial Approximation by Computational Estimation) is a computer-automated facial approximation application jointly developed by the Federal Bureau of Investigation and GE Global Research. The application derives a statistically based approximation of a face from a unidentified skull using a dataset of ~400 human head computer tomography (CT) scans of living adult American individuals from four ancestry groups: African, Asian, European and Hispanic (self-identified). To date only one unpublished subjective recognition study has been conducted using ReFace approximations. It indicated that approximations produced by ReFace were recognized above chance rates (10%). This preliminary study assesses: (i) the recognizability of five ReFace approximations; (ii) the recognizability of CT-derived skin surface replicas of the same individuals whose skulls were used to create the ReFace approximations; and (iii) the relationship between recognition performance and resemblance ratings of target individuals. All five skin surface replicas were recognized at rates statistically significant above chance (22-50%). Four of five ReFace approximations were recognized above chance (5-18%), although with statistical significance only at the higher rate. Such results suggest reconsideration of the usefulness of the type of output format utilized in this study, particularly in regard to facial approximations employed as a means of identifying unknown individuals. PMID:24314512

  11. An integrated computer system for preliminary design of advanced aircraft.

    NASA Technical Reports Server (NTRS)

    Fulton, R. E.; Sobieszczanski, J.; Landrum, E. J.

    1972-01-01

    A progress report is given on the first phase of a research project to develop a system of Integrated Programs for Aerospace-Vehicle Design (IPAD) which is intended to automate to the largest extent possible the preliminary and detailed design of advanced aircraft. The approach used is to build a pilot system and simultaneously to carry out two major contractual studies to define a practical IPAD system preparatory to programing. The paper summarizes the specifications and goals of the IPAD system, the progress to date, and any conclusion reached regarding its feasibility and scope. Sample calculations obtained with the pilot system are given for aircraft preliminary designs optimized with respect to discipline parameters, such as weight or L/D, and these results are compared with designs optimized with respect to overall performance parameters, such as range or payload.

  12. Preliminary Evaluation of a Computer Simulation of Long Cane Use.

    ERIC Educational Resources Information Center

    Chubon, Robert A.; Keith, Ashley D.

    1989-01-01

    Developed and evaluated long cane mobility computer simulation as visual rehabilitation training device and research tool in graduate students assigned to instruction (BI) (N=10) or enhanced instruction (EI) (N=9). Found higher percentage of EI students completed simulation task. Concluded that students registered positive understanding changes,…

  13. COMPUTER ASSISTED PRELIMINARY DESIGN FOR DRINKING WATER TREATMENT PROCESS SYSTEMS

    EPA Science Inventory

    The purpose of the study was to develop an interactive computer program to aid the design engineer in evaluating the performance and cost for any proposed drinking water treatment system consisting of individual unit processes. The 25 unit process models currently in the program ...

  14. Computer-Generated Geometry Instruction: A Preliminary Study

    ERIC Educational Resources Information Center

    Kang, Helen W.; Zentall, Sydney S.

    2011-01-01

    This study hypothesized that increased intensity of graphic information, presented in computer-generated instruction, could be differentially beneficial for students with hyperactivity and inattention by improving their ability to sustain attention and hold information in-mind. To this purpose, 18 2nd-4th grade students, recruited from general…

  15. Development of X-TOOLSS: Preliminary Design of Space Systems Using Evolutionary Computation

    NASA Technical Reports Server (NTRS)

    Schnell, Andrew R.; Hull, Patrick V.; Turner, Mike L.; Dozier, Gerry; Alverson, Lauren; Garrett, Aaron; Reneau, Jarred

    2008-01-01

    Evolutionary computational (EC) techniques such as genetic algorithms (GA) have been identified as promising methods to explore the design space of mechanical and electrical systems at the earliest stages of design. In this paper the authors summarize their research in the use of evolutionary computation to develop preliminary designs for various space systems. An evolutionary computational solver developed over the course of the research, X-TOOLSS (Exploration Toolset for the Optimization of Launch and Space Systems) is discussed. With the success of early, low-fidelity example problems, an outline of work involving more computationally complex models is discussed.

  16. Analyzing high energy physics data using database computing: Preliminary report

    NASA Technical Reports Server (NTRS)

    Baden, Andrew; Day, Chris; Grossman, Robert; Lifka, Dave; Lusk, Ewing; May, Edward; Price, Larry

    1991-01-01

    A proof of concept system is described for analyzing high energy physics (HEP) data using data base computing. The system is designed to scale up to the size required for HEP experiments at the Superconducting SuperCollider (SSC) lab. These experiments will require collecting and analyzing approximately 10 to 100 million 'events' per year during proton colliding beam collisions. Each 'event' consists of a set of vectors with a total length of approx. one megabyte. This represents an increase of approx. 2 to 3 orders of magnitude in the amount of data accumulated by present HEP experiments. The system is called the HEPDBC System (High Energy Physics Database Computing System). At present, the Mark 0 HEPDBC System is completed, and can produce analysis of HEP experimental data approx. an order of magnitude faster than current production software on data sets of approx. 1 GB. The Mark 1 HEPDBC System is currently undergoing testing and is designed to analyze data sets 10 to 100 times larger.

  17. Computer-based thermal imaging of human gingiva: preliminary investigation.

    PubMed

    Barnett, M L; Gilman, R M; Charles, C H; Bartels, L L

    1989-11-01

    Computer-based thermal imaging techniques were used to compare the rewarming rates of normal and inflamed human gingiva following cooling. A Modified Gingival Index (MGI) score, gingival crevicular fluid (GCF) measurement, and clinical photograph were obtained from a maxillary or mandibular anterior facial region in 20 subjects, aged 25 to 44. Baseline thermograms of the marginal/papillary (M/P) and adjacent attached gingiva (AG) were recorded following an acclimatization period with the patient seated and chin resting on a positioning apparatus. The tissue was then cooled with a gentle stream of air and thermograms were recorded at 10 second intervals for 3 minutes as the tissue rewarmed. Rewarming slopes were calculated based on these thermograms. Correlation coefficients were calculated for MGI with GCF, as well as for both MGI and GCF with AG and M/P rewarming slopes. Mean baseline (SE) temperatures (degrees F) for AG were 75.9 (0.9), 78.0 (0.6), and 80.3 (1.3) for normal, mildly inflamed, and moderately-severely inflamed gingivae, respectively; corresponding mean (SE) temperature differences (degrees F) between AG and M/P were 0.5 (0.2), 0.9 (0.2), and 1.4 (0.3). Intragroup mean M/P temperatures were less than mean AG temperatures, with the mean regional differences increasing with greater severity of inflammation. Rewarming rates also increased as inflammation became more severe, with the rewarming slopes of both the AG and M/P having statistically significant correlations with the MGI and the GCF. The correlation between MGI and GCF was also statistically significant. This study suggests that computer-based thermal imaging techniques can detect both static and dynamic temperature differences between normal gingiva and gingivae with increasing severities of inflammation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2600750

  18. A preliminary study of molecular dynamics on reconfigurable computers

    SciTech Connect

    Wolinski, C.; Trouw, F. R.; Gokhale, M.

    2003-01-01

    In this paper we investigate the performance of platform FPGAs on a compute-intensive, floating-point-intensive supercomputing application, Molecular Dynamics (MD). MD is a popular simulation technique to track interacting particles through time by integrating their equations of motion. One part of the MD algorithm was implemented using the Fabric Generator (FG)[l I ] and mapped onto several reconfigurable logic arrays. FG is a Java-based toolset that greatly accelerates construction of the fabrics from an abstract technology independent representation. Our experiments used technology-independent IEEE 32-bit floating point operators so that the design could be easily re-targeted. Experiments were performed using both non-pipelined and pipelined floating point modules. We present results for the Altera Excalibur ARM System on a Programmable Chip (SoPC), the Altera Strath EPlS80, and the Xilinx Virtex-N Pro 2VP.50. The best results obtained were 5.69 GFlops at 8OMHz(Altera Strath EPlS80), and 4.47 GFlops at 82 MHz (Xilinx Virtex-II Pro 2VF50). Assuming a lOWpower budget, these results compare very favorably to a 4Gjlop/40Wprocessing/power rate for a modern Pentium, suggesting that reconfigurable logic can achieve high performance at low power on jloating-point-intensivea pplications.

  19. Preliminary Computational Analysis of the (HIRENASD) Configuration in Preparation for the Aeroelastic Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Chwalowski, Pawel; Florance, Jennifer P.; Heeg, Jennifer; Wieseman, Carol D.; Perry, Boyd P.

    2011-01-01

    This paper presents preliminary computational aeroelastic analysis results generated in preparation for the first Aeroelastic Prediction Workshop (AePW). These results were produced using FUN3D software developed at NASA Langley and are compared against the experimental data generated during the HIgh REynolds Number Aero- Structural Dynamics (HIRENASD) Project. The HIRENASD wind-tunnel model was tested in the European Transonic Windtunnel in 2006 by Aachen University0s Department of Mechanics with funding from the German Research Foundation. The computational effort discussed here was performed (1) to obtain a preliminary assessment of the ability of the FUN3D code to accurately compute physical quantities experimentally measured on the HIRENASD model and (2) to translate the lessons learned from the FUN3D analysis of HIRENASD into a set of initial guidelines for the first AePW, which includes test cases for the HIRENASD model and its experimental data set. This paper compares the computational and experimental results obtained at Mach 0.8 for a Reynolds number of 7 million based on chord, corresponding to the HIRENASD test conditions No. 132 and No. 159. Aerodynamic loads and static aeroelastic displacements are compared at two levels of the grid resolution. Harmonic perturbation numerical results are compared with the experimental data using the magnitude and phase relationship between pressure coefficients and displacement. A dynamic aeroelastic numerical calculation is presented at one wind-tunnel condition in the form of the time history of the generalized displacements. Additional FUN3D validation results are also presented for the AGARD 445.6 wing data set. This wing was tested in the Transonic Dynamics Tunnel and is commonly used in the preliminary benchmarking of computational aeroelastic software.

  20. Evaluation of a tuberculous abscess on the right side of the diaphragm with contrast-enhanced computed tomography: A case report

    PubMed Central

    DONG, PENG; CHEN, JING-JING; WANG, XI-ZHEN

    2016-01-01

    We herein investigate the case of a patient with a tuberculous diaphragmatic abscess confirmed by pathology. The patient underwent plain computed tomography (CT) examination of the chest and contrast-enhanced abdominal CT examination. The abscess appeared as hypodense mass with thick and irregular wall, which was enhanced on the contrast-enhanced CT images. The shape of the mass resembled an irregular double convex lens. No enlarged lymph nodes were detected on the CT images. The presence of a tuberculous diaphragmatic abscess should be suspected in patients with a diaphragmatic hypodense mass with enhanced thick walls, even when there is absence of enlarged lymph nodes on the CT images. PMID:27330800

  1. A preliminary transient-fault experiment on the SIFT computer system

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Elks, Carl R.

    1987-01-01

    This paper presents the results of a preliminary experiment to study the effectiveness of a fault-tolerant system's ability to handle transient faults. The primary goal of the experiment was to develop the techniques to measure the parameters needed for a reliability analysis of the SIFT computer system which includes th effects of transient faults. A key aspect of such an analysis is the determination of the effectiveness of the operating system's ability to discriminate between transient and permanent faults. A detailed description of the preliminary transient fault experiment along with the results from 297 transient fault injections are given. Although not enough data was obtained to draw statistically significant conclusions, the foundation has been laid for a large-scale transient fault experiment.

  2. OPDOT: A computer program for the optimum preliminary design of a transport airplane

    NASA Technical Reports Server (NTRS)

    Sliwa, S. M.; Arbuckle, P. D.

    1980-01-01

    A description of a computer program, OPDOT, for the optimal preliminary design of transport aircraft is given. OPDOT utilizes constrained parameter optimization to minimize a performance index (e.g., direct operating cost per block hour) while satisfying operating constraints. The approach in OPDOT uses geometric descriptors as independent design variables. The independent design variables are systematically iterated to find the optimum design. The technical development of the program is provided and a program listing with sample input and output are utilized to illustrate its use in preliminary design. It is not meant to be a user's guide, but rather a description of a useful design tool developed for studying the application of new technologies to transport airplanes.

  3. Rayleigh to Compton ratio scatter tomography applied to breast cancer diagnosis: A preliminary computational study

    NASA Astrophysics Data System (ADS)

    Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.

    2014-02-01

    In the present work, a tomographic technique based on Rayleigh to Compton scattering ratio (R/C) was studied using computational simulation in order to assess its application to breast cancer diagnosis. In this preliminary study, some parameters that affect the image quality were evaluated, such as: (i) energy beam, (ii) size and glandularity of the breast, and (iii) statistical count noise. The results showed that the R/C contrast increases with increasing photon energy and decreases with increasing glandularity of the sample. The statistical noise showed to be a significant parameter, although the quality of the obtained images was acceptable for a considerable range of noise level. The preliminary results suggest that the R/C tomographic technique has a potential of being applied as a complementary tool in the breast cancer diagnostic.

  4. Preliminary design methods for fiber reinforced composite structures employing a personal computer

    NASA Technical Reports Server (NTRS)

    Eastlake, C. N.

    1986-01-01

    The objective of this project was to develop a user-friendly interactive computer program to be used as an analytical tool by structural designers. Its intent was to do preliminary, approximate stress analysis to help select or verify sizing choices for composite structural members. The approach to the project was to provide a subroutine which uses classical lamination theory to predict an effective elastic modulus for a laminate of arbitrary material and ply orientation. This effective elastic modulus can then be used in a family of other subroutines which employ the familiar basic structural analysis methods for isotropic materials. This method is simple and convenient to use but only approximate, as is appropriate for a preliminary design tool which will be subsequently verified by more sophisticated analysis. Additional subroutines have been provided to calculate laminate coefficient of thermal expansion and to calculate ply-by-ply strains within a laminate.

  5. Comparative evaluation of soft and hard tissue dimensions in the anterior maxilla using radiovisiography and cone beam computed tomography: A pilot study

    PubMed Central

    Mallikarjun, Savita; Babu, Harsha Mysore; Das, Sreedevi; Neelakanti, Abhilash; Dawra, Charu; Shinde, Sachin Vaijnathrao

    2016-01-01

    Aims: To assess and compare the thickness of gingiva in the anterior maxilla using radiovisiography (RVG) and cone beam computed tomography (CBCT) and its correlation with the thickness of underlying alveolar bone. Settings and Design: This cross-sectional study included 10 male subjects in the age group of 20–45 years. Materials and Methods: After analyzing the width of keratinized gingiva of the maxillary right central incisor, the radiographic assessment was done using a modified technique for RVG and CBCT, to measure the thickness of both the labial gingiva and labial plate of alveolar bone at 4 predetermined locations along the length of the root in each case. Statistical Analysis Used: Statistical analysis was performed using Student's t-test and Pearson's correlation test, with the help of statistical software (SPSS V13). Results: No statistically significant differences were obtained in the measurement made using RVG and CBCT. The results of the present study also failed to reveal any significant correlation between the width of gingiva and the alveolar bone in the maxillary anterior region. Conclusions: Within the limitations of this study, it can be concluded that both CBCT and RVG can be used as valuable tools in the assessment of the soft and hard tissue dimensions. PMID:27143830

  6. Micro- and nano-X-ray computed-tomography: A step forward in the characterization of the pore network of a leached cement paste

    SciTech Connect

    Bossa, Nathan; Chaurand, Perrine; Vicente, Jérôme; Borschneck, Daniel; Levard, Clément; Aguerre-Chariol, Olivier; Rose, Jérôme

    2015-01-15

    Pore structure of leached cement pastes (w/c = 0.5) was studied for the first time from micro-scale down to the nano-scale by combining micro- and nano-X-ray computed tomography (micro- and nano-CT). This allowed assessing the 3D heterogeneity of the pore network along the cement profile (from the core to the altered layer) of almost the entire range of cement pore size, i.e. from capillary to gel pores. We successfully quantified an increase of porosity in the altered layer at both resolutions. Porosity is increasing from 1.8 to 6.1% and from 18 to 58% at the micro-(voxel = 1.81 μm) and nano-scale (voxel = 63.5 nm) respectively. The combination of both CT allowed to circumvent weaknesses inherent of both investigation scales. In addition the connectivity and the channel size of the pore network were also evaluated to obtain a complete 3D pore network characterization at both scales.

  7. A Rare Case of Type III Dens Invaginatus in a Mandibular Second Premolar and Its Nonsurgical Endodontic Management by Using Cone-beam Computed Tomography: A Case Report.

    PubMed

    Agrawal, Pritesh Kisanlal; Wankhade, Jyoti; Warhadpande, Manjusha

    2016-04-01

    Invaginated teeth present technical difficulties in clinical management because of their abnormal anatomic configuration. Endodontic clinical management of type III dens invaginatus can be greatly enhanced by newer techniques and materials such as cone-beam computed tomography (CBCT), mineral trioxide aggregate, and platelet-rich fibrin. This case report presents a 13-year-old male patient with type III dens invaginatus (DI) in left mandibular second premolar with history of recurrent swelling. Pulp testing revealed no response with the tooth. Dens invaginatus type III with an immature apex and periapical lesion was seen on radiograph. The case was diagnosed as Oehlers type III DI with pulp necrosis and chronic apical abscess. The treatment was planned and performed by using CBCT imaging. CBCT was performed to see the canal anatomy and to know the size of periapical lesion. Root canal treatment was completed in 2 visits. Calcium hydroxide dressing was placed in the first visit. In the second visit MTA was used for apexification in the main canal, and warm vertical compaction technique with gutta-percha was used in the invaginated canal. At the 2-year reevaluation, the patient was asymptomatic, and his tooth had remained functional since the treatment was completed. Radiographic assessment of the tooth showed significant osseous healing of the preoperative lesion. Three-dimensional imaging is a valuable tool for endodontic management of teeth with complex internal anatomy. PMID:26874642

  8. Analysis of C-shaped canal systems in mandibular second molars using surgical operating microscope and cone beam computed tomography: A clinical approach

    PubMed Central

    Chhabra, Sanjay; Yadav, Seema; Talwar, Sangeeta

    2014-01-01

    Aims: The study was aimed to acquire better understanding of C-shaped canal systems in mandibular second molar teeth through a clinical approach using sophisticated techniques such as surgical operating microscope and cone beam computed tomography (CBCT). Materials and Methods: A total of 42 extracted mandibular second molar teeth with fused roots and longitudinal grooves were collected randomly from native Indian population. Pulp chamber floors of all specimens were examined under surgical operating microscope and classified into four types (Min's method). Subsequently, samples were subjected to CBCT scan after insertion of K-files size #10 or 15 into each canal orifice and evaluated using the cross-sectional and 3-dimensional images in consultation with dental radiologist so as to obtain more accurate results. Minimum distance between the external root surface on the groove and initial file placed in the canal was also measured at different levels and statistically analyzed. Results: Out of 42 teeth, maximum number of samples (15) belonged to Type-II category. A total of 100 files were inserted in 86 orifices of various types of specimens. Evaluation of the CBCT scan images of the teeth revealed that a total of 21 canals were missing completely or partially at different levels. The mean values for the minimum thickness were highest at coronal followed by middle and apical third levels in all the categories. Lowest values were obtained for teeth with Type-III category at all three levels. Conclusions: The present study revealed anatomical variations of C-shaped canal system in mandibular second molars. The prognosis of such complex canal anatomies can be improved by simultaneous employment of modern techniques such as surgical operating microscope and CBCT. PMID:24944447

  9. The Square Kilometre Array Science Data Processor. Preliminary compute platform design

    NASA Astrophysics Data System (ADS)

    Broekema, P. C.; van Nieuwpoort, R. V.; Bal, H. E.

    2015-07-01

    The Square Kilometre Array is a next-generation radio-telescope, to be built in South Africa and Western Australia. It is currently in its detailed design phase, with procurement and construction scheduled to start in 2017. The SKA Science Data Processor is the high-performance computing element of the instrument, responsible for producing science-ready data. This is a major IT project, with the Science Data Processor expected to challenge the computing state-of-the art even in 2020. In this paper we introduce the preliminary Science Data Processor design and the principles that guide the design process, as well as the constraints to the design. We introduce a highly scalable and flexible system architecture capable of handling the SDP workload.

  10. On the computation of preliminary orbits for Earth satellites with radar observations

    NASA Astrophysics Data System (ADS)

    Gronchi, G. F.; Dimare, L.; Bracali Cioci, D.; Ma, H.

    2015-08-01

    We introduce a new method to perform preliminary orbit determination for satellites on low Earth orbits (LEO). This method works with tracks of radar observations: each track is composed by n ≥ 4 topocentric position vectors per pass of the satellite, taken at very short time intervals. We assume very accurate values for the range ρ, while the angular positions (i.e. the line of sight, given by the pointing of the antenna) are less accurate. We wish to correct the errors in the angular positions already in the computation of a preliminary orbit. With the information contained in a pair of radar tracks, using the laws of the two-body dynamics, we can write eight equations in eight unknowns. The unknowns are the components of the topocentric velocity orthogonal to the line of sight at the two mean epochs of the tracks, and the corrections Δ to be applied to the angular positions. We take advantage of the fact that the components of Δ are typically small. We show the results of some tests, performed with simulated observations, and compare this method with Gibbs' and the Keplerian integrals methods.

  11. Computational analysis and preliminary redesign of the nozzle contour of the Langley hypersonic CF4 tunnel

    NASA Technical Reports Server (NTRS)

    Thompson, R. A.; Sutton, Kenneth

    1987-01-01

    A computational analysis, modification, and preliminary redesign study was performed on the nozzle contour of the Langley Hypersonic CF4 Tunnel. This study showed that the existing nozzle was contoured incorrectly for the design operating condition, and this error was shown to produce the measured disturbances in the exit flow field. A modified contour was designed for the current nozzle downstream of the maximum turning point that would provide a uniform exit flow. New nozzle contours were also designed for an exit Mach number and Reynolds number combination which matches that attainable in the Langley 20-Inch Mach 6 Tunnel. Two nozzle contours were designed: one having the same exit radius but a larger mass flow rate than that of the existing CF4 Tunnel, and the other having the same mass flow rate but a smaller exit radius than that of the existing CF4 Tunnel.

  12. Development of an online automatic computed radiography dose data mining program: a preliminary study.

    PubMed

    Ng, Curtise K C; Sun, Zhonghua

    2010-01-01

    Recent studies have reported the computed radiography (CR) dose creep problem and therefore the need to have monitoring processes in place in clinical departments. The objective of this study is to provide a better technological solution to implement a regular CR dose monitoring process. An online automatic CR dose data mining program which can be applied to different systems was developed based on freeware and existing softwares in the Picture Archiving and Communication System (PACS) server. The program was tested with 69 CR images. This preliminary study shows that the program addresses the major weaknesses of some existing studies including involvement of manual procedures in the monitoring process and being only applicable to a single manufacturer's CR images. The proposed method provides an efficient and effective solution to implement a CR dose monitoring program regularly in busy clinical departments to regulate the dose creep problem so as to reinforce the 'As Low As Reasonably Achievable' (ALARA) principle. PMID:19640604

  13. Feasibility Study for a Remote Terminal Central Computing Facility Serving School and College Institutions. Volume II, Preliminary Specifications.

    ERIC Educational Resources Information Center

    International Business Machines Corp., White Plains, NY.

    Preliminary specifications of major equipment and programing systems characteristics for a remote terminal central computing facility serving 25-75 secondary schools are presented. Estimation techniques developed in a previous feasibility study were used to delineate workload demands for four model regions with different numbers of institutions…

  14. Functional Analysis and Preliminary Specifications for a Single Integrated Central Computer System for Secondary Schools and Junior Colleges. Interim Report.

    ERIC Educational Resources Information Center

    1968

    The present report proposes a central computing facility and presents the preliminary specifications for such a system. It is based, in part, on the results of earlier studies by two previous contractors on behalf of the U.S. Office of Education. The recommendations are based upon the present contractors considered evaluation of the earlier…

  15. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... revalue such reserves on a net level premium basis for the purpose of determining the amount which may be... the reserves for all such contracts had been computed on a net level premium basis (using the same mortality or morbidity assumptions and interest rates for both the preliminary term basis and the net...

  16. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... a net level premium basis for the purpose of determining the amount which may be taken into account... reserves for all such contracts had been computed on a net level premium basis (using the same mortality or morbidity assumptions and interest rates for both the preliminary term basis and the net level premium...

  17. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 8 2014-04-01 2014-04-01 false Election with respect to life insurance reserves computed on preliminary term basis. 1.818-4 Section 1.818-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Miscellaneous Provisions § 1.818-4 Election with respect...

  18. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... revalue such reserves on a net level premium basis for the purpose of determining the amount which may be... the reserves for all such contracts had been computed on a net level premium basis (using the same mortality or morbidity assumptions and interest rates for both the preliminary term basis and the net...

  19. Detection of the posterior superior alveolar artery in the lateral sinus wall using computed tomography/cone beam computed tomography: a prevalence meta-analysis study and systematic review.

    PubMed

    Varela-Centelles, P; Loira-Gago, M; Seoane-Romero, J M; Takkouche, B; Monteiro, L; Seoane, J

    2015-11-01

    A systematic search of MEDLINE, Embase, and Proceedings Web of Science was undertaken to assess the prevalence of the posterior superior alveolar artery (PSAA) in the lateral sinus wall in sinus lift patients, as identified using computed tomography (CT)/cone beam computed tomography (CBCT). For inclusion, the article had to report PSAA detection in the bony wall using CT and/or CBCT in patients with subsinus edentulism. Studies on post-mortem findings, mixed samples (living and cadaveric), those presenting pooled results only, or studies performed for a sinus pathology were excluded. Heterogeneity was checked using an adapted version of the DerSimonian and Laird Q test, and quantified by calculating the proportion of the total variance due to between-study variance (Ri statistic). Eight hundred and eleven single papers were reviewed and filtered according to the inclusion/exclusion criteria. Ten studies were selected (1647 patients and 2740 maxillary sinuses (study unit)). The pooled prevalence of PSAA was 62.02 (95% confidence interval (CI) 46.33-77.71). CBCT studies detected PSAA more frequently (78.12, 95% CI 61.25-94.98) than CT studies (51.19, 95% CI 42.33-60.05). Conventional CT revealed thicker arteries than CBCT. It is concluded that PSAA detection is more frequent when CBCT explorations are used. Additional comparative studies controlling for potential confounding factors are needed to ascertain the actual diagnostic value of radiographic explorations for assessing the PSAA prior to sinus floor elevation procedures. PMID:26215383

  20. Computer-aided detection of HER2 amplification status using FISH images: a preliminary study

    NASA Astrophysics Data System (ADS)

    Zheng, Bin; Wang, Xiao-Hui; Surti, Urvashi; Bhargava, Rohit; Gur, David

    2009-02-01

    The amplification status of human epidermal growth factor receptors 2 (HER2) genes is strongly associated with clinical outcome in patients with breast cancer. The American Society of Clinical Oncology Tumor Marker Guidelines Panel has recommended routine testing of HER2 status on all newly diagnosed metastatic breast cancers since 2001. Although fluorescent in situ hybridization (FISH) technology provides superior accuracy as compared with other approaches, current manual FISH analysis methods are somewhat subjective, tedious, and may introduce interreader variability. The goal of this preliminary study is to develop and test a computer-aided detection (CAD) scheme to assess HER2 status using FISH images. Forty FISH images were selected for this study from our genetic laboratory. The CAD scheme first applies an adaptive, iterative threshold method followed by a labeling algorithm to segment cells of possible interest. A set of classification rules is then used to identify analyzable interphase cells and discard nonanalyzable cells due to cell overlapping and/or other image staining debris (or artifacts). The scheme then maps the detected analyzable cells onto two other gray scale images corresponding to the red and green color of the original image followed by application of a raster scan and labeling algorithms to separately detect the HER-2/neu ("red") and CEP17 ("green") FISH signals. A simple distance based criterion is applied to detect and merge split FISH signals within each cell. The CAD scheme computes the ratio between independent "red" and "green" FISH signals of all analyzable cells identified on an image. If the ratio is >= 2.0, the FISH image is assumed to have been acquired from a HER2+ case; otherwise, the FISH image is assumed to have been acquired from HER2- case. When we applied the CAD scheme to the testing dataset, the average computed HER2 amplification ratios were 1.06+/-0.25 and 2.53+/-0.81 for HER2- and HER2+ samples, respectively. The

  1. Wolter X-Ray Microscope Computed Tomography Ray-Trace Model with Preliminary Simulation Results

    SciTech Connect

    Jackson, J A

    2006-02-27

    It is proposed to build a Wolter X-ray Microscope Computed Tomography System in order to characterize objects to sub-micrometer resolution. Wolter Optics Systems use hyperbolic, elliptical, and/or parabolic mirrors to reflect x-rays in order to focus or magnify an image. Wolter Optics have been used as telescopes and as microscopes. As microscopes they have been used for a number of purposes such as measuring emission x-rays and x-ray fluoresce of thin biological samples. Standard Computed Tomography (CT) Systems use 2D radiographic images, from a series of rotational angles, acquired by passing x-rays through an object to reconstruct a 3D image of the object. The x-ray paths in a Wolter X-ray Microscope will be considerably different than those of a standard CT system. There is little information about the 2D radiographic images that can be expected from such a system. There are questions about the quality, resolution and focusing range of an image created with such a system. It is not known whether characterization information can be obtained from these images and whether these 2D images can be reconstructed to 3D images of the object. A code has been developed to model the 2D radiographic image created by an object in a Wolter X-ray Microscope. This code simply follows the x-ray through the object and optics. There is no modeling at this point of other effects, such as scattering, reflection losses etc. Any object, of appropriate size, can be used in the model code. A series of simulations using a number of different objects was run to study the effects of the optics. The next step will be to use this model to reconstruct an object from the simulated data. Funding for the project ended before this goal could be accomplished. The following documentation includes: (1) background information on current X-ray imaging systems, (2) background on Wolter Optics, (3) description of the Wolter System being used, (4) purpose, limitations and development of the modeling

  2. The Development of a Computer Model for Projecting Statewide College Enrollments: A Preliminary Study.

    ERIC Educational Resources Information Center

    Rensselaer Research Corp., Troy, NY.

    The purpose of this study was to develop the schema and methodology for the construction of a computerized mathematical model designed to project college and university enrollments in New York State and to meet the future increased demands of higher education planners. This preliminary report describes the main structure of the proposed computer…

  3. Effects of Animated Computer Simulations on Inductive Learning with Adults: A Preliminary Report.

    ERIC Educational Resources Information Center

    Rieber, Lloyd P.; Parmley, M. Wayne

    The purpose of this study was to investigate the effects of interactive learning strategies in the form of visually-based, real-time computer simulations on inductive learning by adults in physical science. The subjects were 160 upperclass undergraduate students who were enrolled in an introductory computer education class. The computer based…

  4. Computer-Based Reading Programs: A Preliminary Investigation of Two Parent Implemented Programs with Students At-Risk for Reading Failure

    ERIC Educational Resources Information Center

    Pindiprolu, Sekhar S.; Forbush, David

    2009-01-01

    In 2000, National Reading Panelists (NRP) reported that computer delivered reading instruction has potential for promoting the reading skills of students at-risk for reading failure. However, panelists also noted a scarcity of data present in the literature on the effects of computer-based reading instruction. This preliminary investigation…

  5. Reducing Foreign Language Communication Apprehension with Computer-Mediated Communication: A Preliminary Study

    ERIC Educational Resources Information Center

    Arnold, Nike

    2007-01-01

    Many studies (e.g., [Beauvois, M.H., 1998. "E-talk: Computer-assisted classroom discussion--attitudes and motivation." In: Swaffar, J., Romano, S., Markley, P., Arens, K. (Eds.), "Language learning online: Theory and practice in the ESL and L2 computer classroom." Labyrinth Publications, Austin, TX, pp. 99-120; Bump, J., 1990. "Radical changes in…

  6. Applying Computer Technology to Substance Abuse Prevention Science Results of a Preliminary Examination

    ERIC Educational Resources Information Center

    Marsch, Lisa A.; Bickel, Warren K.; Badger, Gary J.

    2007-01-01

    This manuscript reports on the development and evaluation of a computer-based substance abuse prevention program for middle school-aged adolescents, called "HeadOn: Substance Abuse Prevention for Grades 6-8TM". This self-guided program was designed to deliver effective drug abuse prevention science to youth via computer-based educational…

  7. How Well Can a Computer Program Teach German Culture? Some Preliminary Findings from EthnoDeutsch.

    ERIC Educational Resources Information Center

    Ashby, Wendy; Ostertag, Veronica

    2002-01-01

    Investigates the effectiveness of an interactive, computer-mediated instructional segment designed to educate students about ethnicity in German-speaking countries. Fifty-two intermediate German students worked with computer-mediated segments and rated the segments' effectiveness on a Likert-scale questionnaire. (AS)

  8. Preliminary Computational Fluid Dynamics (CFD) Simulation of EIIB Push Barge in Shallow Water

    NASA Astrophysics Data System (ADS)

    Beneš, Petr; Kollárik, Róbert

    2011-12-01

    This study presents preliminary CFD simulation of EIIb push barge in inland conditions using CFD software Ansys Fluent. The RANSE (Reynolds Averaged Navier-Stokes Equation) methods are used for the viscosity solution of turbulent flow around the ship hull. Different RANSE methods are used for the comparison of their results in ship resistance calculations, for selecting the appropriate and removing inappropriate methods. This study further familiarizes on the creation of geometrical model which considers exact water depth to vessel draft ratio in shallow water conditions, grid generation, setting mathematical model in Fluent and evaluation of the simulations results.

  9. Preliminary study of the use of the STAR-100 computer for transonic flow calculations

    NASA Technical Reports Server (NTRS)

    Keller, J. D.; Jameson, A.

    1977-01-01

    An explicit method for solving the transonic small-disturbance potential equation is presented. This algorithm, which is suitable for the new vector-processor computers such as the CDC STAR-100, is compared to successive line over-relaxation (SLOR) on a simple test problem. The convergence rate of the explicit scheme is slower than that of SLOR, however, the efficiency of the explicit scheme on the STAR-100 computer is sufficient to overcome the slower convergence rate and allow an overall speedup compared to SLOR on the CYBER 175 computer.

  10. Comparison of different methods to compute a preliminary orbit of Space Debris using radar observations

    NASA Astrophysics Data System (ADS)

    Ma, Hélène; Gronchi, Giovanni F.

    2014-07-01

    We advertise a new method of preliminary orbit determination for space debris using radar observations, which we call Infang †. We can perform a linkage of two sets of four observations collected at close times. The context is characterized by the accuracy of the range ρ, whereas the right ascension α and the declination δ are much more inaccurate due to observational errors. This method can correct α, δ, assuming the exact knowledge of the range ρ. Considering no perturbations from the J 2 effect, but including errors in the observations, we can compare the new method, the classical method of Gibbs, and the more recent Keplerian integrals method. The development of Infang is still on-going and will be further improved and tested.

  11. Investigating the role of combined acoustic-visual feedback in one-dimensional synchronous brain computer interfaces, a preliminary study.

    PubMed

    Gargiulo, Gaetano D; Mohamed, Armin; McEwan, Alistair L; Bifulco, Paolo; Cesarelli, Mario; Jin, Craig T; Ruffo, Mariano; Tapson, Jonathan; van Schaik, André

    2012-01-01

    Feedback plays an important role when learning to use a brain computer interface (BCI), particularly in the case of synchronous feedback that relies on the interaction subject. In this preliminary study, we investigate the role of combined auditory-visual feedback during synchronous μ rhythm-based BCI sessions to help the subject to remain focused on the selected imaginary task. This new combined feedback, now integrated within the general purpose BCI2000 software, has been tested on eight untrained and three trained subjects during a monodimensional left-right control task. In order to reduce the setup burden and maximize subject comfort, an electroencephalographic device suitable for dry electrodes that required no skin preparation was used. Quality and index of improvement was evaluated based on a personal self-assessment questionnaire from each subject and quantitative data based on subject performance. Results for this preliminary study show that the combined feedback was well tolerated by the subjects and improved performance in 75% of the naïve subjects compared with visual feedback alone. PMID:23152713

  12. Preliminary Computational Study for Future Tests in the NASA Ames 9 foot' x 7 foot Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Pearl, Jason M.; Carter, Melissa B.; Elmiligui, Alaa A.; WInski, Courtney S.; Nayani, Sudheer N.

    2016-01-01

    The NASA Advanced Air Vehicles Program, Commercial Supersonics Technology Project seeks to advance tools and techniques to make over-land supersonic flight feasible. In this study, preliminary computational results are presented for future tests in the NASA Ames 9 foot x 7 foot supersonic wind tunnel to be conducted in early 2016. Shock-plume interactions and their effect on pressure signature are examined for six model geometries. Near- field pressure signatures are assessed using the CFD code USM3D to model the proposed test geometries in free-air. Additionally, results obtained using the commercial grid generation software Pointwise Reigistered Trademark are compared to results using VGRID, the NASA Langley Research Center in-house mesh generation program.

  13. Psychological underpinnings of intrafamilial computer-mediated communication: a preliminary exploration of CMC uptake with parents and siblings.

    PubMed

    Goby, Valerie Priscilla

    2011-06-01

    This preliminary study investigates the uptake of computer-mediated communication (CMC) with parents and siblings, an area on which no research appears to have been conducted. Given the lack of relevant literature, grounded theory methodology was used and online focus group discussions were conducted in an attempt to generate suitable hypotheses for further empirical studies. Codification of the discussion data revealed various categories of meaning, namely: a perceived inappropriateness of CMC with members of family of origin; issues relating to the family generational gap; the nature of the offline sibling/parent relationship; the non-viability of online affordances such as planned self-disclosure, deception, identity construction; and disinhibition in interactions with family-of-origin members. These themes could be molded into hypotheses to assess the psychosocial limitations of CMC and to determine if it can indeed become a ubiquitous alternative to traditional communication modes as some scholars have claimed. PMID:21114409

  14. SIFT - A preliminary evaluation. [Software Implemented Fault Tolerant computer for aircraft control

    NASA Technical Reports Server (NTRS)

    Palumbo, D. L.; Butler, R. W.

    1983-01-01

    This paper presents the results of a performance evaluation of the SIFT computer system conducted in the NASA AIRLAB facility. The essential system functions are described and compared to both earlier design proposals and subsequent design improvements. The functions supporting fault tolerance are found to consume significant computing resources. With SIFT's specimen task load, scheduled at a 30-Hz rate, the executive tasks such as reconfiguration, clock synchronization and interactive consistency, require 55 percent of the available task slots. Other system overhead (e.g., voting and scheduling) use an average of 50 percent of each remaining task slot.

  15. Cognitive Styles among Computer Systems Students: Preliminary Findings from New Arrivals to University.

    ERIC Educational Resources Information Center

    Moore, Sarah; O'Maidin, Donncha; McElligot, Annette

    2003-01-01

    Explored the relationship among cognitive style, performance, gender, and communication among computer students. Found a significant relationship between performance and cognitive style; students whose cognitive style scores indicated a preference for analytical thinking had better performance scores when entering college than those with a…

  16. Computer-Animated Instruction and Students' Conceptual Change in Electrochemistry: Preliminary Qualitative Analysis

    ERIC Educational Resources Information Center

    Talib, Othman; Matthews, Robert; Secombe, Margaret

    2005-01-01

    This paper discusses the potential of applying computer-animated instruction (CAnI) as an effective conceptual change strategy in teaching electrochemistry in comparison to conventional lecture-based instruction (CLI). The core assumption in this study is that conceptual change in learners is an active, constructive process that is enhanced by the…

  17. Monitor Tone Generates Stress in Computer and VDT Operators: A Preliminary Study.

    ERIC Educational Resources Information Center

    Dow, Caroline; Covert, Douglas C.

    A near-ultrasonic pure tone of 15,570 Herz generated by flyback transformers in computer and video display terminal (VDT) monitors may cause severe non-specific irritation or stress disease in operators. Women hear higher frequency sounds than men and are twice as sensitive to "too loud" noise. Pure tones at high frequencies are more annoying than…

  18. Computational implementation of a systems prioritization methodology for the Waste Isolation Pilot Plant: A preliminary example

    SciTech Connect

    Helton, J.C.; Anderson, D.R.; Baker, B.L.

    1996-04-01

    A systems prioritization methodology (SPM) is under development to provide guidance to the US DOE on experimental programs and design modifications to be supported in the development of a successful licensing application for the Waste Isolation Pilot Plant (WIPP) for the geologic disposal of transuranic (TRU) waste. The purpose of the SPM is to determine the probabilities that the implementation of different combinations of experimental programs and design modifications, referred to as activity sets, will lead to compliance. Appropriate tradeoffs between compliance probability, implementation cost and implementation time can then be made in the selection of the activity set to be supported in the development of a licensing application. Descriptions are given for the conceptual structure of the SPM and the manner in which this structure determines the computational implementation of an example SPM application. Due to the sophisticated structure of the SPM and the computational demands of many of its components, the overall computational structure must be organized carefully to provide the compliance probabilities for the large number of activity sets under consideration at an acceptable computational cost. Conceptually, the determination of each compliance probability is equivalent to a large numerical integration problem. 96 refs., 31 figs., 36 tabs.

  19. Computer-Mediated Communication and the Gallaudet University Community: A Preliminary Report

    ERIC Educational Resources Information Center

    Hogg, Nanette M.; Lomicky, Carol S.; Weiner, Stephen F.

    2008-01-01

    The study examined the use of computer-mediated communication (CMC) among individuals involved in a conflict sparked by the appointment of an administrator as president-designate of Gallaudet University in 2006. CMC was defined to comprise forms of communication used for transmitting (sharing) information through networks with digital devices.…

  20. MANIPULATION PAD--PRELIMINARY REPORT ON A STUDENT-COMPUTER INTERFACE DEVICE FOR PROGRAMMED INSTRUCTION.

    ERIC Educational Resources Information Center

    BALL, J.R.; AND OTHERS

    AN INVESTIGATION WAS MADE OF SOME ENTIRELY NEW INPUT-OUTPUT DEVICES DESIGNED TO SOLVE SOME FUNCTIONAL AND ECONOMIC PROBLEMS THAT ARE PRESENT IN EXISTING COMPUTER-CONTROLLED INSTRUCTION EQUIPMENT. THREE FORMS OF MANIPULATION PAD WERE STUDIED. INFORMATION ABOUT SPECIALLY PREPARED OBJECTS PLACED ON THE FLAT SURFACE OF THE PAD WAS SUPPLIED TO A…

  1. Keewatin Region Educational Authority Pilot Education Project: Computer-Assisted Learning. Preliminary Final Report.

    ERIC Educational Resources Information Center

    Wolter, Heidi; And Others

    A project was conducted to improve and expand academic upgrading, job readiness, and special skill training for adults in the Keewatin Region through the implementation of computer-assisted learning (CAL). It was intended as a response to the special needs of unemployed Inuit who were not reached in the past by traditional training programs and…

  2. Single-photon emission computed tomography in human immunodeficiency virus encephalopathy: A preliminary report

    SciTech Connect

    Masdeu, J.C.; Yudd, A.; Van Heertum, R.L.; Grundman, M.; Hriso, E.; O'Connell, R.A.; Luck, D.; Camli, U.; King, L.N. )

    1991-08-01

    Depression or psychosis in a previously asymptomatic individual infected with the human immunodeficiency virus (HIV) may be psychogenic, related to brain involvement by the HIV or both. Although prognosis and treatment differ depending on etiology, computed tomography (CT) and magnetic resonance imaging (MRI) are usually unrevealing in early HIV encephalopathy and therefore cannot differentiate it from psychogenic conditions. Thirty of 32 patients (94%) with HIV encephalopathy had single-photon emission computed tomography (SPECT) findings that differed from the findings in 15 patients with non-HIV psychoses and 6 controls. SPECT showed multifocal cortical and subcortical areas of hypoperfusion. In 4 cases, cognitive improvement after 6-8 weeks of zidovudine (AZT) therapy was reflected in amelioration of SPECT findings. CT remained unchanged. SPECT may be a useful technique for the evaluation of HIV encephalopathy.

  3. Computer code for preliminary sizing analysis of axial-flow turbines

    NASA Technical Reports Server (NTRS)

    Glassman, Arthur J.

    1992-01-01

    This mean diameter flow analysis uses a stage average velocity diagram as the basis for the computational efficiency. Input design requirements include power or pressure ratio, flow rate, temperature, pressure, and rotative speed. Turbine designs are generated for any specified number of stages and for any of three types of velocity diagrams (symmetrical, zero exit swirl, or impulse) or for any specified stage swirl split. Exit turning vanes can be included in the design. The program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, flow angles, and last stage absolute and relative Mach numbers. An analysis is presented along with a description of the computer program input and output with sample cases. The analysis and code presented herein are modifications of those described in NASA-TN-D-6702. These modifications improve modeling rigor and extend code applicability.

  4. High-accuracy computation of Delta V magnitude probability densities - Preliminary remarks

    NASA Technical Reports Server (NTRS)

    Chadwick, C.

    1986-01-01

    This paper describes an algorithm for the high accuracy computation of some statistical quantities of the magnitude of a random trajectory correction maneuver (TCM). The trajectory correction velocity increment Delta V is assumed to be a three-component random vector with each component being a normally distributed random scalar having a possibly nonzero mean. Knowledge of the statitiscal properties of the magnitude of a random TCM is important in the planning and execution of maneuver strategies for deep-space missions such as Galileo. The current algorithm involves the numerical integration of a set of differential equations. This approach allows the computation of density functions for specific Delta V magnitude distributions to high accuracy without first having to generate large numbers of random samples. Possible applications of the algorithm to maneuver planning, planetary quarantine evaluation, and guidance success probability calculations are described.

  5. X-ray phase computed tomography for nanoparticulated imaging probes and therapeutics: preliminary feasibility study

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Yang, Yi; Tang, Shaojie

    2011-03-01

    With the scientific progress in cancer biology, pharmacology and biomedical engineering, the nano-biotechnology based imaging probes and therapeutical agents (namely probes/agents) - a form of theranostics - are among the strategic solutions bearing the hope for the cure of cancer. The key feature distinguishing the nanoparticulated probes/agents from their conventional counterparts is their targeting capability. A large surface-to-volume ratio in nanoparticulated probes/agents enables the accommodation of multiple targeting, imaging and therapeutic components to cope with the intra- and inter-tumor heterogeneity. Most nanoparticulated probes/agents are synthesized with low atomic number materials and thus their x-ray attenuation are very similar to biological tissues. However, their microscopic structures are very different, which may result in significant differences in their refractive properties. Recently, the investigation in the x-ray grating-based differential phase contrast (DPC) CT has demonstrated its advantages in differentiating low-atomic materials over the conventional attenuation-based CT. We believe that a synergy of x-ray grating-based DPC CT and nanoparticulated imaging probes and therapeutic agents may play a significant role in extensive preclinical and clinical applications, or even become a modality for molecular imaging. Hence, we propose to image the refractive property of nanoparticulated imaging probes and therapeutical agents using x-ray grating-based DPC CT. In this work, we conduct a preliminary feasibility study with a focus to characterize the contrast-to-noise ratio (CNR) and contrast-detail behavior of the x-ray grating-based DPC CT. The obtained data may be instructive to the architecture design and performance optimization of the x-ray grating-based DPC CT for imaging biomarker-targeted imaging probes and therapeutic agents, and even informative to the translation of preclinical research in theranostics into clinical applications.

  6. An integrated computer-program-system for the preliminary design of advanced hypersonic aircraft (PrADO-Hy)

    NASA Astrophysics Data System (ADS)

    Kossira, H.; Bardenhagen, A.; Heinze, W.

    The design program system PrADO-Hy (Preliminary Aircraft Design and Optimization - Hypersonic) for computer-aided conceptional hypersonic aircraft design, developed by the Institute of Aircraft Design and Structural Mechanics (IFL, TU Braunschweig), is introduced. The modular program simulates, controlled by a data management system, in its kernel the design process with the interactions between the different disciplines (aerodynamics, propulsion, structure, flight mechanics, etc.). The design process is superimposed by a multivariable optimization loop. This paper describes the organization of the PrADO system, the data management technique, and as an example of the program library the weight and balance module for the estimation of structural mass. The practical application and the capabilities of the program system are demonstrated by a design study of a TSTO (two-stage-to-orbit) vehicle, which should transfer a space payload of 3.3 tons to a low-earth-orbit (80 km/450 km). The computational results of some investigations will be presented.

  7. Preliminary results of very fast computation of Moment Magnitude and focal mechanism in the context of tsunami warning

    NASA Astrophysics Data System (ADS)

    Schindelé, François; Roch, Julien; Rivera, Luis

    2015-04-01

    Various methodologies were recently developed to compute the moment magnitude and the focal mechanism, thanks to the real time access to numerous broad-band seismic data. Several methods were implemented at the CENALT, in particular the W-Phase method developed by H. Kanamori and L. Rivera. For earthquakes of magnitudes in the range 6.5-9.0, this method provides accurate results in less than 40 minutes. The context of the tsunami warning in Mediterranean, a small basin impacted in less than one hour, and with small sources but some with high tsunami potential (Boumerdes 2003), a comprehensive tsunami warning system in that region should include very fast computation of the seismic parameters. The results of the values of Mw, the focal depth and the type of fault (reverse, normal, strike-slip) are the most relevant parameters expected for the tsunami warning. Preliminary results will be presented using data in the North-eastern and Mediterranean region for the recent period 2010-2014. This work is funded by project ASTARTE - - Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839

  8. A Comparison between the Occurrence of Pauses, Repetitions and Recasts under Conditions of Face-to-Face and Computer-Mediated Communication: A Preliminary Study

    ERIC Educational Resources Information Center

    Cabaroglu, Nese; Basaran, Suleyman; Roberts, Jon

    2010-01-01

    This study compares pauses, repetitions and recasts in matched task interactions under face-to-face and computer-mediated conditions. Six first-year English undergraduates at a Turkish University took part in Skype-based voice chat with a native speaker and face-to-face with their instructor. Preliminary quantitative analysis of transcripts showed…

  9. Computed tomography of the meniscus of the temporomandibular joint: preliminary observations

    SciTech Connect

    Helms, C.A.; Morrish, R.B. Jr.; Kircos, L.T.; Dolwick, M.F.

    1982-12-01

    Anterior displacement of the meniscus of the temporomandibular joint (TMJ) was diagnosed in nine patients who had undergone arthrography, and they were later examined with computed tomography (CT) to see if this modality could supplant arthrography in some patients with TMJ dysfunction. The anteriorly displaced menisci were visualizsed in all nine patients by using sagittal reformations and blink mode. Four of the nine patients had the diagnosis confirmed at surgery. The precise protocol for the CT examination and how to interpret it are discussed. We are optimistic that CT may replace TMJ arthrography in selected patients.

  10. A preliminary computer pattern analysis of satellite images of mature extratropical cyclones

    NASA Technical Reports Server (NTRS)

    Burfeind, Craig R.; Weinman, James A.; Barkstrom, Bruce R.

    1987-01-01

    This study has applied computerized pattern analysis techniques to the location and classification of features of several mature extratropical cyclones that were depicted in GOES satellite images. These features include the location of the center of the cyclone vortex core and the location of the associated occluded front. The cyclone type was classified in accord with the scheme of Troup and Streten. The present analysis was implemented on a personal computer; results were obtained within approximately one or two minutes without the intervention of an analyst.

  11. Feature Extraction on Brain Computer Interfaces using Discrete Dyadic Wavelet Transform: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Gareis, I.; Gentiletti, G.; Acevedo, R.; Rufiner, L.

    2011-09-01

    The purpose of this work is to evaluate different feature extraction alternatives to detect the event related evoked potential signal on brain computer interfaces, trying to minimize the time employed and the classification error, in terms of sensibility and specificity of the method, looking for alternatives to coherent averaging. In this context the results obtained performing the feature extraction using discrete dyadic wavelet transform using different mother wavelets are presented. For the classification a single layer perceptron was used. The results obtained with and without the wavelet decomposition were compared; showing an improvement on the classification rate, the specificity and the sensibility for the feature vectors obtained using some mother wavelets.

  12. Computed nasal resistance compared with patient-reported symptoms in surgically treated nasal airway passages: A preliminary report

    PubMed Central

    Garcia, Guilherme J. M.; Frank, Dennis O.; Cannon, Daniel E.; Pawar, Sachin S.; Rhee, John S.

    2012-01-01

    Background: Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. Methods: Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). Results: In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. Conclusion: These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated. PMID:22643935

  13. Experience with computed tomography (CT) pelvimetry in Ibadan, Nigeria: a preliminary report.

    PubMed

    Obajimi, M O; Omigbodun, A O; Ogunseyinde, A O; Adekunle, A O

    2001-09-01

    Computed tomography (CT) pelvimetry has largely replaced conventional radiography in the antenatal assessment of pelvic dimensions, but its usefulness in the Nigerian setting is yet to be assessed. This study was undertaken to ascertain if there is a relationship between antenatal CT pelvimetric measurements and the mode of delivery at the end of the pregnancy. A group of thirty-one patients who had antenatal pelvimetry were categorised into two groups depending on whether they achieved vaginal delivery or not and the pelvimetric and other obstetrrc characteristics of the two groups were compared. The only parameters that showed statistically significant differences between the groups were the higher maternal height and the lower head circumference in the neonates of women achieving vaginal delivery. The findings suggest that fetal parameters may be more predictive of mode of delivery than absolute pelvic measurements. PMID:14510137

  14. Development of a Computer Program for Analyzing Preliminary Aircraft Configurations in Relationship to Emerging Agility Metrics

    NASA Technical Reports Server (NTRS)

    Bauer, Brent

    1993-01-01

    This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition, one study illustrates the module's ability to optimize a configuration's agility performance.

  15. Identification of false‐negative and false‐positive diagnoses of lymph node metastases in non‐small cell lung cancer patients staged by integrated 18F‐fluorodeoxyglucose‐positron emission tomography/computed tomography: A retrospective cohort study

    PubMed Central

    Watanabe, Ken‐ichi; Asakura, Keisuke; Kazama, Akio; Ozawa, Yukihiko

    2016-01-01

    Background The aim of this study was to evaluate the diagnostic accuracy of integrated 18 F‐fluorodeoxyglucose positron emission tomography/computed tomography (FDG‐PET/CT) in hilar and mediastinal lymph node (HMLN) staging of non‐small cell lung cancer (NSCLC), and to investigate potential risk factors for false‐negative and false‐positive HMLN metastases. Methods We examined the data of 388 surgically resected NSCLC patients preoperatively staged by integrated FDG‐PET/CT. Risk factors for false‐negative and false‐positive HMLN metastases were analyzed using univariate and multivariate analyses of clinicopathological factors. Results The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of integrated FDG‐PET/CT in detecting HMLN metastases were 47.4%, 91.0%, 56.3%, 87.7%, and 82.5%, respectively. On multivariate analysis, the maximum standardized uptake value (SUVmax) of the tumor (P = 0.042), adenocarcinoma (P = 0.003), and tumor size (P = 0.017) were risk factors for false‐negative HMLN metastases, and history of lung disease (P = 0.006) and tumor location (central; P = 0.025) were risk factors for false‐positive HMLN metastases. Conclusions The present study identified risk factors for false‐negative and false‐positive HMLN metastases in NSCLC patients staged by preoperative integrated FDG‐PET/CT. These findings would be helpful in selecting appropriate candidates for mediastinoscopy or endobronchial ultrasound‐guided transbronchial needle aspiration.

  16. Functionalized synchrotron in-line phase-contrast computed tomography: a novel approach for simultaneous quantification of structural alterations and localization of barium-labelled alveolar macrophages within mouse lung samples.

    PubMed

    Dullin, Christian; dal Monego, Simeone; Larsson, Emanuel; Mohammadi, Sara; Krenkel, Martin; Garrovo, Chiara; Biffi, Stefania; Lorenzon, Andrea; Markus, Andrea; Napp, Joanna; Salditt, Tim; Accardo, Agostino; Alves, Frauke; Tromba, Giuliana

    2015-01-01

    Functionalized computed tomography (CT) in combination with labelled cells is virtually non-existent due to the limited sensitivity of X-ray-absorption-based imaging, but would be highly desirable to realise cell tracking studies in entire organisms. In this study we applied in-line free propagation X-ray phase-contrast CT (XPCT) in an allergic asthma mouse model to assess structural changes as well as the biodistribution of barium-labelled macrophages in lung tissue. Alveolar macrophages that were barium-sulfate-loaded and fluorescent-labelled were instilled intratracheally into asthmatic and control mice. Mice were sacrificed after 24 h, lungs were kept in situ, inflated with air and scanned utilizing XPCT at the SYRMEP beamline (Elettra Synchrotron Light Source, Italy). Single-distance phase retrieval was used to generate data sets with ten times greater contrast-to-noise ratio than absorption-based CT (in our setup), thus allowing to depict and quantify structural hallmarks of asthmatic lungs such as reduced air volume, obstruction of airways and increased soft-tissue content. Furthermore, we found a higher concentration as well as a specific accumulation of the barium-labelled macrophages in asthmatic lung tissue. It is believe that XPCT will be beneficial in preclinical asthma research for both the assessment of therapeutic response as well as the analysis of the role of the recruitment of macrophages to inflammatory sites. PMID:25537601

  17. Using Gender Schema Theory to Examine Gender Equity in Computing: a Preliminary Study

    NASA Astrophysics Data System (ADS)

    Agosto, Denise E.

    Women continue to constitute a minority of computer science majors in the United States and Canada. One possible contributing factor is that most Web sites, CD-ROMs, and other digital resources do not reflect girls' design and content preferences. This article describes a pilot study that considered whether gender schema theory can serve as a framework for investigating girls' Web site design and content preferences. Eleven 14- and 15-year-old girls participated in the study. The methodology included the administration of the Children's Sex-Role Inventory (CSRI), Web-surfing sessions, interviews, and data analysis using iterative pattern coding. On the basis of their CSRI scores, the participants were divided into feminine-high (FH) and masculine-high (MH) groups. Data analysis uncovered significant differences in the criteria the groups used to evaluate Web sites. The FH group favored evaluation criteria relating to graphic and multimedia design, whereas the MH group favored evaluation criteria relating to subject content. Models of the two groups' evaluation criteria are presented, and the implications of the findings are discussed.

  18. Preliminary validation of computational procedures for a new atmospheric ionizing radiation (AIR) model.

    PubMed

    Clem, John M; De Angelis, Giovanni; Goldhagen, Paul; Wilson, John W

    2003-01-01

    A new computational procedure to determine particle fluxes in the Earth's atmosphere is presented. The primary cosmic ray spectrum has been modeled through an analysis of simultaneous proton and helium measurements made on high altitude balloon flights and spacecraft. An improved global fit to the data was achieved through applying a unique technique utilizing the Fokker-Plank equation with a non-linear rigidity-dependent diffusion coefficient. The propagation of primary particles through the Earth's atmosphere is calculated with a three-dimensional Monte Carlo transport program called FLUKA. Primary protons and helium nuclei (alphas) are generated within the rigidity range of 0.5 GV-20 TV uniform in cos2 theta. For a given location, primaries above the effective cutoff rigidity are transported through the atmosphere. Alpha particles are initially transported with a separate package called HEAVY to simulate fragmentation. This package interfaces with FLUKA to provide interaction starting points for each nucleon originating from a helium nucleus. Results from this calculation are presented and compared to measurements. PMID:14727659

  19. A preliminary analysis of quantifying computer security vulnerability data in "the wild"

    NASA Astrophysics Data System (ADS)

    Farris, Katheryn A.; McNamara, Sean R.; Goldstein, Adam; Cybenko, George

    2016-05-01

    A system of computers, networks and software has some level of vulnerability exposure that puts it at risk to criminal hackers. Presently, most vulnerability research uses data from software vendors, and the National Vulnerability Database (NVD). We propose an alternative path forward through grounding our analysis in data from the operational information security community, i.e. vulnerability data from "the wild". In this paper, we propose a vulnerability data parsing algorithm and an in-depth univariate and multivariate analysis of the vulnerability arrival and deletion process (also referred to as the vulnerability birth-death process). We find that vulnerability arrivals are best characterized by the log-normal distribution and vulnerability deletions are best characterized by the exponential distribution. These distributions can serve as prior probabilities for future Bayesian analysis. We also find that over 22% of the deleted vulnerability data have a rate of zero, and that the arrival vulnerability data is always greater than zero. Finally, we quantify and visualize the dependencies between vulnerability arrivals and deletions through a bivariate scatterplot and statistical observations.

  20. Preliminary Computational Hemodynamics Study of Double Aortic Aneurysms under Multistage Surgical Procedures: An Idealised Model Study

    PubMed Central

    Otsuki, Yosuke; Bui Minh, Nhat; Ohtake, Hiroshi; Watanabe, Go; Matsuzawa, Teruo

    2013-01-01

    Double aortic aneurysm (DAA) falls under the category of multiple aortic aneurysms. Repair is generally done through staged surgery due to low invasiveness. In this approach, one aneurysm is cured per operation. Therefore, two operations are required for DAA. However, post-first-surgery rupture cases have been reported. Although the problems involved with managing staged surgery have been discussed for more than 30 years, investigation from a hemodynamic perspective has not been attempted. Hence, this is the first computational fluid dynamics approach to the DAA problem. Three idealized geometries were prepared: presurgery, thoracic aortic aneurysm (TAA) cured, and abdominal aortic aneurysm (AAA) cured. By applying identical boundary conditions for flow rate and pressure, the Navier-Stokes equation and continuity equations were solved under the Newtonian fluid assumption. Average pressure in TAA was increased by AAA repair. On the other hand, average pressure in AAA was decreased after TAA repair. Average wall shear stress was decreased at the peak in post-first-surgery models. However, the wave profile of TAA average wall shear stress was changed in the late systole phase after AAA repair. Since the average wall shear stress in the post-first-surgery models decreased and pressure at TAA after AAA repair increased, the TAA might be treated first to prevent rupture. PMID:24348172

  1. Use of ultrafast computed tomography to quantitate regional myocardial perfusion: a preliminary report

    SciTech Connect

    Rumberger, J.A.; Feiring, A.J.; Lipton, M.J.; Higgins, C.B.; Ell, S.R.; Marcus, M.L.

    1987-01-01

    The purpose of this study was to assess the potential for rapid acquisition computed axial tomography (Imatron C-100) to quantify regional myocardial perfusion. Myocardial and left ventricular cavity contrast clearance curves were constructed after injecting nonionic contrast (1 ml/kg over 2 to 3 seconds) into the inferior vena cava of six anesthetized, closed chest dogs (n = 14). Independent myocardial perfusion measurements were obtained by coincident injection of radiolabeled microspheres into the left atrium during control, intermediate and maximal myocardial vasodilation with adenosine (0.5 to 1.0 mg/kg per min, intravenously, respectively). At each flow state, 40 serial short-axis scans of the left ventricle were taken near end-diastole at the midpapillary muscle level. Contrast clearance curves were generated and analyzed from the left ventricular cavity and posterior papillary muscle regions after excluding contrast recirculation and minimizing partial volume effects. The area under the curve (gamma variate function) was determined for a region of interest placed within the left ventricular cavity. Characteristics of contrast clearance data from the posterior papillary muscle region that were evaluated included the peak myocardial opacification, area under the contrast clearance curve and a contrast clearance time defined by the full width/half maximal extent of the clearance curve. Myocardial perfusion (microspheres) ranged from 35 to 450 ml/100 g per min (mean 167 +/- 125).

  2. Is early response by 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography a predictor of long-term outcome in patients with metastatic colorectal cancer?

    PubMed Central

    Fanelli, Marcello Ferretti; Dettino, Aldo Lourenço Abadde; Nicolau, Ulisses Ribaldo; Cavicchioli, Marcelo; Lima, Eduardo Nóbrega Pereira; de Mello, Celso Abdon Lopes

    2016-01-01

    Background Identify in advance responder patients to chemotherapy in metastatic colorectal cancer (CRC) would allow prompt interruption of ineffective therapies in non-responder patients. Hence, predictive markers are sought in numerous trials to detect responder patients, including tumor shrinkage measured by imaging methods. Usually, Response Evaluation Criteria in Solid Tumors (RECIST) is used to evaluate tumor response in metastatic CRC, but these criteria are questionable with use of biological agents associated to chemotherapy. Our aim was correlate early metabolic response by 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (18FDG-PET-CT) with long-term outcome in metastatic CRC in first-line therapy. Methods We prospectively evaluated 36 patients with metastatic CRC in first-line treatment with 5-fluorouracil, leucovorin (folinic acid), oxaliplatin (FOLFOX) or 5-fluorouracil, leucovorin (folinic acid), irinotecan (FOLFIRI) associated with cetuximab or bevacizumab. 18FDG-PET-CT was performed at baseline and after two cycles of chemotherapy. The early metabolic response [standardized uptake value (SUV)] was measured to identify responder and non-responder patients and correlated with overall survival (OS) and progression-free survival (PFS). Results Median age was 58.5 years (range, 41–74 years). PFS was 15.5 months for responder and 13.3 months for non-responder (P=0.42), OS was 55.7 months for responder and not reached for non-responder. There was no correlation between delta-SUV and clinical and pathological variables analyzed. In the subgroup of patients who did not undergo resection of metastasis (45%), PFS was higher for responders (15.3×6.8 months, P=0.02). Conclusions According to our findings, early response by 18FDG-PET-CT was not a predictor of long-term outcome for patients with metastatic CRC treated in the first-line chemotherapy with a monoclonal antibody. PMID:27284468

  3. A noninvasive computational method for fluid resuscitation monitoring in pediatric burns: a preliminary report.

    PubMed

    Stewart, Camille L; Mulligan, Jane; Grudic, Greg Z; Pyle, Laura; Moulton, Steven L

    2015-01-01

    The fluid resuscitation needs of children with small area burns are difficult to predict. The authors hypothesized that a novel computational algorithm called the compensatory reserve index (CRI), calculated from the photoplethysmogram waveform, would correlate with percent total body surface area (%TBSA) and fluid administration in children presenting with ≤20% TBSA burns. The authors recorded photoplethysmogram waveforms from burn-injured children that were later processed by the CRI algorithm. A CRI of 1 represents supine normovolemia; a CRI of 0 represents the point at which a subject is predicted to experience hemodynamic decompensation. CRI values from the first 10 minutes of monitoring were compared to clinical data. Waveform data were available for 27 children with small to moderate sized burns (4-20 %TBSA). The average age was 6.3 ± 1.1 years, the average %TBSA was 10.4 ± 0.8%, and the average CRI was 0.36 ± 0.03. CRI inversely correlated with the %TBSA (P < .001). Twenty children were transferred with an average reported %TBSA of 16.5 ± 1.4%, which was significantly higher than the actual %TBSA (P < .001). CRI correlated better with actual %TBSA compared to reported %TBSA (P = .02). CRI correlated with the amount of fluid resuscitation given at the time of CRI measurement (P = .02) and was inversely related to total fluids given per 24 hours for children with adequate urine output (>0.5 ml/kg/hr) (P < .001). The CRI is decreased in children with small to moderate size burns, and correlates with %TBSA and fluid administration. This suggests that the CRI may be useful for fluid resuscitation guidance, warranting further study. PMID:25383980

  4. Application of Computed Tomography Virtual Noncontrast Spectral Imaging in Evaluation of Hepatic Metastases: A Preliminary Study

    PubMed Central

    Tian, Shi-Feng; Liu, Ai-Lian; Liu, Jing-Hong; Sun, Mei-Yu; Wang, He-Qing; Liu, Yi-Jun

    2015-01-01

    Objective: The objective was to qualitatively and quantitatively evaluate hepatic metastases using computed tomography (CT) virtual noncontrast (VNC) spectral imaging in a retrospective analysis. Methods: Forty hepatic metastases patients underwent CT scans including the conventional true noncontrast (TNC) and the tri-phasic contrast-enhanced dual energy spectral scans in the hepatic arterial, portal venous, and equilibrium phases. The tri-phasic spectral CT images were used to obtain three groups of VNC images including in the arterial (VNCa), venous (VNCv), and equilibrium (VNCe) phase by the material decomposition process using water and iodine as a base material pair. The image quality and the contrast-to-noise ratio (CNR) of metastasis of the four groups were compared with ANOVA analysis. The metastasis detection rates with the four nonenhanced image groups were calculated and compared using the Chi-square test. Results: There were no significant differences in image quality among TNC, VNCa and VNCv images (P > 0.05). The quality of VNCe images was significantly worse than that of other three groups (P < 0.05). The mean CNR of metastasis in the TNC and VNCs images was 1.86, 2.42, 1.92, and 1.94, respectively; the mean CNR of metastasis in VNCa images was significantly higher than that in other three groups (P < 0.05), while no statistically significant difference was observed among VNCv, VNCe and TNC images (P > 0.05). The metastasis detection rate of the four nonenhanced groups with no statistically significant difference (P > 0.05). Conclusions: The quality of VNCa and VNCv images is identical to that of TNC images, and the metastasis detection rate in VNC images is similar to that in TNC images. VNC images obtained from arterial phase show metastases more clearly. Thus, VNCa imaging may be a surrogate to TNC imaging in hepatic metastasis diagnosis. PMID:25698191

  5. Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Wuu, Cheng-Shie

    2013-02-01

    The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub-millimeter accuracy of

  6. [ECT versus transcranial magnetic stimulation (TMS): preliminary data of computer modeling].

    PubMed

    Zyss, T; Krawczyk, A; Drzymała, P; Starzyński, J

    1999-01-01

    The essential issue of electroshock therapy (ECT) is the activity of physical stimulus, i.e., the electric current, on the disturbed structures of the brain. ECT sessions--when chronically applied for evoking antidepressive effects--are responsible for the appearance of excessive incitement in the neuronal net in the brain tissue in a form of self-sustaining after-discharge (SSAD) (convulsive attack characteristic for ECT). The study presents the computer research on basic biophysical phenomena of electroshock therapy (flow of electric current in the structures of the head just before convulsive attack). Five-layer 3-D model of the head was created in OPERA-3D (Vector Fields Ltd., Oxford), general 3 dimensional issues solver. Geometrical dimensions and electrophysical properties of each layer correspond with natural properties. The model was subjected to the action of electric stimulation (parameters identical to those applied in clinical conditions). Analysis of the flow in particular layers revealed the crawling/spreading effect present not only in the scalp layer but also in the layer of cerebrospinal fluid. The effect is conditioned by "deeper situated" lesser conduction of electricity-respectively skull bones, brain tissue. Crawling effect is the reason why only 5-15% of the electricity applied on the surface of the head reaches the surface of the brain. Electro-stimulation examinations also showed that the values of the so called density of the current in layers of brain tissue balanced between 1-10 mA/mm2. The current parameters of ECT were effective in evoking subsequent convulsive attack and safe for the brain tissue. The model was subjected to the action of magnetic stimulation according to the parameters of neurologic technique of transcranial magnetic stimulation (TMS). ELECTRA module was used to solve wire-current issues. The examination showed more regular distribution of current vectors in all layers of the head. The density of cerebral cortex was 0

  7. Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results.

    PubMed

    Xu, Y; Wuu, Cheng-Shie

    2013-02-01

    The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub

  8. Cloud Computing-based Platform for Drought Decision-Making using Remote Sensing and Modeling Products: Preliminary Results for Brazil

    NASA Astrophysics Data System (ADS)

    Vivoni, E.; Mascaro, G.; Shupe, J. W.; Hiatt, C.; Potter, C. S.; Miller, R. L.; Stanley, J.; Abraham, T.; Castilla-Rubio, J.

    2012-12-01

    Droughts and their hydrological consequences are a major threat to food security throughout the world. In arid and semiarid regions dependent on irrigated agriculture, prolonged droughts lead to significant and recurring economic and social losses. In this contribution, we present preliminary results on integrating a set of multi-resolution drought indices into a cloud computing-based visualization platform. We focused our initial efforts on Brazil due to a severe, on-going drought in a large agricultural area in the northeastern part of the country. The online platform includes drought products developed from: (1) a MODIS-based water stress index (WSI) based on inferences from normalized difference vegetation index and land surface temperature fields, (2) a volumetric water content (VWC) index obtained from application of the NASA CASA model, and (3) a set of AVHRR-based vegetation health indices obtained from NOAA/NESDIS. The drought indices are also presented in terms of anomalies with respect to a baseline period. Since our main objective is to engage stakeholders and decision-makers in Brazil, we incorporated other relevant geospatial data into the platform, including irrigation areas, dams and reservoirs, administrative units and annual climate information. We will also present a set of use cases developed to help stakeholders explore, query and provide feedback that allowed fine-tuning of the drought product delivery, presentation and analysis tools. Finally, we discuss potential next steps in development of the online platform, including applications at finer resolutions in specific basins and at a coarser global scale.

  9. Experience gained on IBM 360 computer in the preliminary processing of telemetry data recorded on magnetic tape

    NASA Technical Reports Server (NTRS)

    Bratkovska, K.

    1975-01-01

    Telemetry data from the 'Copernicus' experiment stored on magnetic tape on the Ural-IX computer are transcribed to the internal memory of the IBM 360 computer. Operations involved in this process are described.

  10. Preliminary TRIGA fuel burn-up evaluation by means of Monte Carlo code and computation based on total energy released during reactor operation

    SciTech Connect

    Borio Di Tigliole, A.; Bruni, J.; Panza, F.; Alloni, D.; Cagnazzo, M.; Magrotti, G.; Manera, S.; Prata, M.; Salvini, A.; Chiesa, D.; Clemenza, M.; Pattavina, L.; Previtali, E.; Sisti, M.; Cammi, A.

    2012-07-01

    Aim of this work was to perform a rough preliminary evaluation of the burn-up of the fuel of TRIGA Mark II research reactor of the Applied Nuclear Energy Laboratory (LENA) of the Univ. of Pavia. In order to achieve this goal a computation of the neutron flux density in each fuel element was performed by means of Monte Carlo code MCNP (Version 4C). The results of the simulations were used to calculate the effective cross sections (fission and capture) inside fuel and, at the end, to evaluate the burn-up and the uranium consumption in each fuel element. The evaluation, showed a fair agreement with the computation for fuel burn-up based on the total energy released during reactor operation. (authors)

  11. Computer-Assisted Learning in Anatomy at the International Medical School in Debrecen, Hungary: A Preliminary Report

    ERIC Educational Resources Information Center

    Kish, Gary; Cook, Samuel A.; Kis, Greta

    2013-01-01

    The University of Debrecen's Faculty of Medicine has an international, multilingual student population with anatomy courses taught in English to all but Hungarian students. An elective computer-assisted gross anatomy course, the Computer Human Anatomy (CHA), has been taught in English at the Anatomy Department since 2008. This course focuses on an…

  12. Preliminary Analysis of a Randomized Trial of Computer Attention Training in Children with Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Steiner, N.; Sidhu, T. K.; Frenette, E. C.; Mitchell, K.; Perrin, E. C.

    2011-01-01

    Clinically significant attention problems among children present a significant obstacle to increasing student achievement. Computer-based attention training holds great promise as a way for schools to address this problem. The aim of this project is to evaluate the efficacy of two computer-based attention training systems in schools. One program…

  13. Monitoring the Microgravity Environment Quality On-board the International Space Station Using Soft Computing Techniques. Part 2; Preliminary System Performance Results

    NASA Technical Reports Server (NTRS)

    Jules, Kenol; Lin, Paul P.; Weiss, Daniel S.

    2002-01-01

    This paper presents the preliminary performance results of the artificial intelligence monitoring system in full operational mode using near real time acceleration data downlinked from the International Space Station. Preliminary microgravity environment characterization analysis result for the International Space Station (Increment-2), using the monitoring system is presented. Also, comparison between the system predicted performance based on ground test data for the US laboratory "Destiny" module and actual on-orbit performance, using measured acceleration data from the U.S. laboratory module of the International Space Station is presented. Finally, preliminary on-orbit disturbance magnitude levels are presented for the Experiment of Physics of Colloids in Space, which are compared with on ground test data. The ground test data for the Experiment of Physics of Colloids in Space were acquired from the Microgravity Emission Laboratory, located at the NASA Glenn Research Center, Cleveland, Ohio. The artificial intelligence was developed by the NASA Glenn Principal Investigator Microgravity Services Project to help the principal investigator teams identify the primary vibratory disturbance sources that are active, at any moment of time, on-board the International Space Station, which might impact the microgravity environment their experiments are exposed to. From the Principal Investigator Microgravity Services' web site, the principal investigator teams can monitor via a dynamic graphical display, implemented in Java, in near real time, which event(s) is/are on, such as crew activities, pumps, fans, centrifuges, compressor, crew exercise, structural modes, etc., and decide whether or not to run their experiments, whenever that is an option, based on the acceleration magnitude and frequency sensitivity associated with that experiment. This monitoring system detects primarily the vibratory disturbance sources. The system has built-in capability to detect both known

  14. Computer-designed selective laser sintering surgical guide and immediate loading dental implants with definitive prosthesis in edentulous patient: A preliminary method

    PubMed Central

    Giacomo, Giovanni Di; Silva, Jorge; Martines, Rodrigo; Ajzen, Sergio

    2014-01-01

    Objective: The aim of this study was to analyze a preliminary method of immediately loading dental implants and a definitive prosthesis based on the computer-aided design/computer-aided manufacturing systems, after 2 years of clinical follow-up. Materials and Methods: The study comprised one patient in good general health with edentulous maxilla. Cone beam computer tomography (CBCT) was performed using a radiographic template. The surgical plan was made using the digital imaging and communications in medicine protocol with ImplantViewer (version 1.9, Anne Solutions, Sao Paulo, SP, Brazil), the surgical planning software. These data were used to produce a selective laser sintering surgical template. A maxilla prototype was used to guide the prosthesis technician in producing the prosthesis. Eight dental implants and a definitive prosthesis were installed on the same day. A post-operative CBCT image was fused with the image of the surgical planning to calculate the deviation between the planned and the placed implants positions. Patient was followed for 2 years. Results: On average, the match between the planned and placed angular deviation was within 6.0 ± 3.4° and the difference in coronal deviation was 0.7 ± 0.3 mm. At the end of the follow-up, neither the implant nor the prosthesis was lost. Conclusions: Considering the limited samples number, it was possible to install the dental implants and a definitive prosthesis on the same day with success. PMID:24966755

  15. The Opinions of the Kindergarten Teachers in Relation to the Introduction of Computers to Nursery Schools: Preliminary Approach

    ERIC Educational Resources Information Center

    Sivropoulou, Irene; Tsapakidou, Aggeliki; Kiridis, Argyris

    2009-01-01

    Computers were introduced in Greek kindergartens of our country with the new curricula for kindergarten, "Inter-disciplinary Integrated Framework of Study Programs," ("Official Journal of the Hellenic Republic," 376 t.B/18-10-2001, article 6), in order to contribute to the spherical growth of children and to extend their…

  16. A Framework for Measuring Student Learning Gains and Engagement in an Introductory Computing Course: A Preliminary Report of Findings

    ERIC Educational Resources Information Center

    Lim, Billy; Hosack, Bryan; Vogt, Paul

    2012-01-01

    This paper describes a framework for measuring student learning gains and engagement in a Computer Science 1 (CS 1) / Information Systems 1 (IS 1) course. The framework is designed for a CS1/IS1 course as it has been traditionally taught over the years as well as when it is taught using a new pedagogical approach with Web services. It enables the…

  17. Preliminary Development of a Workstation for Craniomaxillofacial Surgical Procedures: Introducing a Computer-Assisted Planning and Execution System

    PubMed Central

    Gordon, Chad R.; Murphy, Ryan J.; Coon, Devin; Basafa, Ehsan; Otake, Yoshito; Al Rakan, Mohammed; Rada, Erin; Susarla, Sriniras; Swanson, Edward; Fishman, Elliot; Santiago, Gabriel; Brandacher, Gerald; Liacouras, Peter; Grant, Gerald; Armand, Mehran

    2014-01-01

    Introduction Facial transplantation represents one of the most complicated scenarios in craniofacial surgery because of skeletal, aesthetic, and dental discrepancies between donor and recipient. However, standard off-the-shelf vendor computer-assisted surgery systems may not provide custom features to mitigate the increased complexity of this particular procedure. We propose to develop a computer-assisted surgery solution customized for preoperative planning, intraoperative navigation including cutting guides, and dynamic, instantaneous feedback of cephalometric measurements/angles as needed for facial transplantation. Methods We developed the Computer-Assisted Planning and Execution (CAPE) workstation to assist with planning and execution of facial transplantation. Preoperative maxillofacial computed tomography (CT) scans were obtained on 4 size-mismatched miniature swine encompassing 2 live face-jaw-teeth transplants. The system was tested in a laboratory setting using plastic models of mismatched swine, after which the system was used in 2 live swine transplants. Postoperative CT imaging was obtained and compared with the preoperative plan and intraoperative measures from the CAPE workstation for both transplants. Results Plastic model tests familiarized the team with the CAPE workstation and identified several defects in the workflow. Live swine surgeries demonstrated utility of the CAPE system in the operating room, showing submillimeter registration error of 0.6 ± 0.24 mm and promising qualitative comparisons between intraoperative data and postoperative CT imaging. Conclusions The initial development of the CAPE workstation demonstrated integration of computer planning and intraoperative navigation for facial transplantation are possible with submillimeter accuracy. This approach can potentially improve preoperative planning, allowing ideal donor-recipient matching despite significant size mismatch, and accurate surgical execution. PMID:24406592

  18. An analysis of Space Shuttle countdown activities: Preliminaries to a computational model of the NASA Test Director

    NASA Technical Reports Server (NTRS)

    John, Bonnie E.; Remington, Roger W.; Steier, David M.

    1991-01-01

    Before all systems are go just prior to the launch of a space shuttle, thousands of operations and tests have been performed to ensure that all shuttle and support subsystems are operational and ready for launch. These steps, which range from activating the orbiter's flight computers to removing the launch pad from the itinerary of the NASA tour buses, are carried out by launch team members at various locations and with highly specialized fields of expertise. The liability for coordinating these diverse activities rests with the NASA Test Director (NTD) at NASA-Kennedy. The behavior is being studied of the NTD with the goal of building a detailed computational model of that behavior; the results of that analysis to date are given. The NTD's performance is described in detail, as a team member who must coordinate a complex task through efficient audio communication, as well as an individual taking notes and consulting manuals. A model of the routine cognitive skill used by the NTD to follow the launch countdown procedure manual was implemented using the Soar cognitive architecture. Several examples are given of how such a model could aid in evaluating proposed computer support systems.

  19. Design and preliminary evaluation of the FINGER rehabilitation robot: controlling challenge and quantifying finger individuation during musical computer game play

    PubMed Central

    2014-01-01

    Background This paper describes the design and preliminary testing of FINGER (Finger Individuating Grasp Exercise Robot), a device for assisting in finger rehabilitation after neurologic injury. We developed FINGER to assist stroke patients in moving their fingers individually in a naturalistic curling motion while playing a game similar to Guitar Hero®a. The goal was to make FINGER capable of assisting with motions where precise timing is important. Methods FINGER consists of a pair of stacked single degree-of-freedom 8-bar mechanisms, one for the index and one for the middle finger. Each 8-bar mechanism was designed to control the angle and position of the proximal phalanx and the position of the middle phalanx. Target positions for the mechanism optimization were determined from trajectory data collected from 7 healthy subjects using color-based motion capture. The resulting robotic device was built to accommodate multiple finger sizes and finger-to-finger widths. For initial evaluation, we asked individuals with a stroke (n = 16) and without impairment (n = 4) to play a game similar to Guitar Hero® while connected to FINGER. Results Precision design, low friction bearings, and separate high speed linear actuators allowed FINGER to individually actuate the fingers with a high bandwidth of control (−3 dB at approximately 8 Hz). During the tests, we were able to modulate the subject’s success rate at the game by automatically adjusting the controller gains of FINGER. We also used FINGER to measure subjects’ effort and finger individuation while playing the game. Conclusions Test results demonstrate the ability of FINGER to motivate subjects with an engaging game environment that challenges individuated control of the fingers, automatically control assistance levels, and quantify finger individuation after stroke. PMID:24495432

  20. Design of a Tablet Computer App for Facilitation of a Molecular Blood Culture Test in Clinical Microbiology and Preliminary Usability Evaluation

    PubMed Central

    Pape-Haugaard, Louise; Meltzer, Michelle C; Fuchs, Martin; Schønheyder, Henrik C; Hejlesen, Ole

    2016-01-01

    Background User mobility is an important aspect of the development of clinical information systems for health care professionals. Mobile phones and tablet computers have obtained widespread use by health care professionals, offering an opportunity for supporting the access to patient information through specialized applications (apps) while supporting the mobility of the users. The use of apps for mobile phones and tablet computers may support workflow of complex tasks, for example, molecular-based diagnostic tests in clinical microbiology. Multiplex Blood Culture Test (MuxBCT) is a molecular-based diagnostic test used for rapid identification of pathogens in positive blood cultures. To facilitate the workflow of the MuxBCT, a specialized tablet computer app was developed as an accessory to the diagnostic test. The app aims to reduce the complexity of the test by step-by-step guidance of microscopy and to assist users in reaching an exact bacterial or fungal diagnosis based on blood specimen observations and controls. Additionally, the app allows for entry of test results, and communication thereof to the laboratory information system (LIS). Objective The objective of the study was to describe the design considerations of the MuxBCT app and the results of a preliminary usability evaluation. Methods The MuxBCT tablet app was developed and set up for use in a clinical microbiology laboratory. A near-live simulation study was conducted in the clinical microbiology laboratory to evaluate the usability of the MuxBCT app. The study was designed to achieve a high degree of realism as participants carried out a scenario representing the context of use for the MuxBCT app. As the MuxBCT was under development, the scenario involved the use of molecular blood culture tests similar to the MuxBCT for identification of microorganisms from positive blood culture samples. The study participants were observed, and their interactions with the app were recorded. After the study, the

  1. Computer simulations of comet- and asteroidlike bodies passing through the Venusian atmosphere: Preliminary results on atmospheric and ground shock effects

    NASA Technical Reports Server (NTRS)

    Roddy, D.; Hatfield, D.; Hassig, P.; Rosenblatt, M.; Soderblom, L.; Dejong, E.

    1992-01-01

    We have completed computer simulations that model shock effects in the venusian atmosphere caused during the passage of two cometlike bodies 100 m and 1000 m in diameter and an asteroidlike body 10 km in diameter. Our objective is to examine hypervelocity-generated shock effects in the venusian atmosphere for bodies of different types and sizes in order to understand the following: (1) their deceleration and depth of penetration through the atmosphere; and (2) the onset of possible ground-surface shock effects such as splotches, craters, and ejecta formations. The three bodies were chosen to include both a range of general conditions applicable to Venus as well as three specific cases of current interest. These calculations use a new multiphase computer code (DICE-MAZ) designed by California Research & Technology for shock-dynamics simulations in complex environments. The code was tested and calibrated in large-scale explosion, cratering, and ejecta research. It treats a wide range of different multiphase conditions, including material types (vapor, melt, solid), particle-size distributions, and shock-induced dynamic changes in velocities, pressures, temperatures (internal energies), densities, and other related parameters, all of which were recorded in our calculations.

  2. Preliminary studies of coolant by-pass flows in a prismatic very high temperature reactor using computational fluid dynamics

    SciTech Connect

    Hiroyuki Sato; Richard Johnson; Richard Schultz

    2009-09-01

    Three dimensional computational fluid dynamic (CFD) calculations of a typical prismatic very high temperature gas-cooled reactor (VHTR) were conducted to investigate the influence of gap geometry on flow and temperature distributions in the reactor core using commercial CFD code FLUENT. Parametric calculations changing the gap width in a whole core length model of fuel and reflector columns were performed. The simulations show the effects of core by-pass flows in the heated core region by comparing results for several gap widths including zero gap width. The calculation results underline the importance of considering inter-column gap width for the evaluation of maximum fuel temperatures and temperature gradients in fuel blocks. In addition, it is shown that temperatures of core outlet flow from gaps and channels are strongly affected by the gap width of by-pass flow in the reactor core.

  3. A preliminary study of a cloud-computing model for chronic illness self-care support in an underdeveloped country

    PubMed Central

    Piette, John D.; Mendoza-Avelares, Milton O.; Ganser, Martha; Mohamed, Muhima; Marinec, Nicolle; Krishnan, Sheila

    2013-01-01

    Background Although interactive voice response (IVR) calls can be an effective tool for chronic disease management, many regions of the world lack the infrastructure to provide these services. Objective This study evaluated the feasibility and potential impact of an IVR program using a cloud-computing model to improve diabetes management in Honduras. Methods A single group, pre-post study was conducted between June and August 2010. The telecommunications infrastructure was maintained on a U.S. server, and calls were directed to patients’ cell phones using VoIP. Eighty-five diabetes patients in Honduras received weekly IVR disease management calls for six weeks, with automated follow-up emails to clinicians, and voicemail reports to family caregivers. Patients completed interviews at enrollment and a six week follow-up. Other measures included patients’ glycemic control (A1c) and data from the IVR calling system. Results 55% of participants completed the majority of their IVR calls and 33% completed 80% or more. Higher baseline blood pressures, greater diabetes burden, greater distance from the clinic, and better adherence were related to higher call completion rates. Nearly all participants (98%) reported that because of the program, they improved in aspects of diabetes management such as glycemic control (56%) or foot care (89%). Mean A1c’s decreased from 10.0% at baseline to 8.9% at follow-up (p<.01). Most participants (92%) said that if the service were available in their clinic they would use it again. Conclusions Cloud computing is a feasible strategy for providing IVR services globally. IVR self-care support may improve self-care and glycemic control for patients in under-developed countries. PMID:21565655

  4. The use of non-contrast computed tomography and color Doppler ultrasound in the characterization of urinary stones - preliminary results

    PubMed Central

    Bulakçı, Mesut; Tefik, Tzevat; Akbulut, Fatih; Örmeci, Mehmet Tolgahan; Beşe, Caner; Şanlı, Öner; Oktar, Tayfun; Salmaslıoğlu, Artür

    2015-01-01

    Objective To investigate the role of density value in computed tomography (CT) and twinkling artifact observed in color Doppler analysis for the prediction of the mineral composition of urinary stones. Material and methods A total of 42 patients who were operated via percutaneous or endoscopic means and had undergone abdominal non-contrast CT and color Doppler ultrasonography examinations were included in the study. X-ray diffraction method was utilized to analyze a total of 86 stones, and the correlations between calculated density values and twinkling intensities with stone types were investigated for each stone. Results Analyses of extracted stones revealed the presence of 40 calcium oxalate monohydrate, 12 calcium oxalate dihydrate, 9 uric acid, 11 calcium phosphate, and 14 cystine stones. The density values were calculated as 1499±269 Hounsfield Units (HU) for calcium oxalate monohydrate, 1505±221 HU for calcium oxalate dihydrate, 348±67 HU for uric acid, 1106±219 HU for calcium phosphate, and 563±115 HU for cystine stones. The artifact intensities were determined as grade 0 in 15, grade 1 in 32, grade 2 in 24, and grade 3 in 15 stones. Conclusion In case the density value of the stone is measured below 780 HU and grade 3 artifact intensity is determined, it can be inferred that the mineral composition of the stone tends to be cystine. PMID:26623143

  5. Are patterns of bone loss in anorexic and postmenopausal women similar? Preliminary results using high resolution peripheral computed tomography.

    PubMed

    Milos, Gabriella; Häuselmann, Hans-Jörg; Krieg, Marc-Antoine; Rüegsegger, Peter; Gallo, Luigi M

    2014-01-01

    This study intended to compare bone density and architecture in three groups of women: young women with anorexia nervosa (AN), an age-matched control group of young women, and healthy late postmenopausal women. Three-dimensional peripheral quantitative high resolution computed-tomography (HR-pQCT) at the ultradistal radius, a technology providing measures of cortical and trabecular bone density and microarchitecture, was performed in the three cohorts. Thirty-six women with AN aged 18-30 years (mean duration of AN: 5.8 years), 83 healthy late postmenopausal women aged 70-81 as well as 30 age-matched healthy young women were assessed. The overall cortical and trabecular bone density (D100), the absolute thickness of the cortical bone (CTh), and the absolute number of trabecules per area (TbN) were significantly lower in AN patients compared with healthy young women. The absolute number of trabecules per area (TbN) in AN and postmenopausal women was similar, but significantly lower than in healthy young women. The comparison between AN patients and post-menopausal women is of interest because the latter reach bone peak mass around the middle of the fertile age span whereas the former usually lose bone before reaching optimal bone density and structure. This study shows that bone mineral density and bone compacta thickness in AN are lower than those in controls but still higher than those in postmenopause. Bone compacta density in AN is similar as in controls. However, bone inner structure in AN is degraded to a similar extent as in postmenopause. This last finding is particularly troubling. PMID:24084384

  6. Preliminary assessment of facial soft tissue thickness utilizing three-dimensional computed tomography models of living individuals.

    PubMed

    Parks, Connie L; Richard, Adam H; Monson, Keith L

    2014-04-01

    Facial approximation is the technique of developing a representation of the face from the skull of an unknown individual. Facial approximation relies heavily on average craniofacial soft tissue depths. For more than a century, researchers have employed a broad array of tissue depth collection methodologies, a practice which has resulted in a lack of standardization in craniofacial soft tissue depth research. To combat such methodological inconsistencies, Stephan and Simpson 2008 [15] examined and synthesized a large number of previously published soft tissue depth studies. Their comprehensive meta-analysis produced a pooled dataset of averaged tissue depths and a simplified methodology, which the researchers suggest be utilized as a minimum standard protocol for future craniofacial soft tissue depth research. The authors of the present paper collected craniofacial soft tissue depths using three-dimensional models generated from computed tomography scans of living males and females of four self-identified ancestry groups from the United States ranging in age from 18 to 62 years. This paper assesses the differences between: (i) the pooled mean tissue depth values from the sample utilized in this paper and those published by Stephan 2012 [21] and (ii) the mean tissue depth values of two demographically similar subsets of the sample utilized in this paper and those published by Rhine and Moore 1984 [16]. Statistical test results indicate that the tissue depths collected from the sample evaluated in this paper are significantly and consistently larger than those published by Stephan 2012 [21]. Although a lack of published variance data by Rhine and Moore 1984 [16] precluded a direct statistical assessment, a substantive difference was also concluded. Further, the dataset presented in this study is representative of modern American adults and is, therefore, appropriate for use in constructing contemporary facial approximations. PMID:24529417

  7. Computer-aided detection of hepatocellular carcinoma in multiphase contrast-enhanced hepatic CT: a preliminary study

    NASA Astrophysics Data System (ADS)

    Xu, Jian-Wu; Suzuki, Kenji; Hori, Masatoshi; Oto, Aytekin; Baron, Richard

    2011-03-01

    Malignant liver tumors such as hepatocellular carcinoma (HCC) account for 1.25 million deaths each year worldwide. Early detection of HCC is sometimes difficult on CT images because the attenuation of HCC is often similar to that of normal liver parenchyma. Our purpose was to develop computer-aided detection (CADe) of HCC using both arterial phase (AP) and portal-venous phase (PVP) of contrast-enhanced CT images. Our scheme consisted of liver segmentation, tumor candidate detection, feature extraction and selection, and classification of the candidates as HCC or non-lesions. We used a 3D geodesic-active-contour model coupled with a level-set algorithm to segment the liver. Both hyper- and hypo-dense tumors were enhanced by a sigmoid filter. A gradient-magnitude filter followed by a watershed algorithm was applied to the tumor-enhanced images for segmenting closed-contour regions as HCC candidates. Seventy-five morphologic and texture features were extracted from the segmented candidate regions in both AP and PVP images. To select most discriminant features for classification, we developed a sequential forward floating feature selection method directly coupled with a support vector machine (SVM) classifier. The initial CADe before the classification achieved a 100% (23/23) sensitivity with 33.7 (775/23) false positives (FPs) per patient. The SVM with four selected features removed 96.5% (748/775) of the FPs without any removal of the HCCs in a leave-one-lesion-out cross-validation test; thus, a 100% sensitivity with 1.2 FPs per patient was achieved, whereas CADe using AP alone produced 6.4 (147/23) FPs per patient at the same sensitivity level.

  8. Biological characterization of the skin of shortfin mako shark Isurus oxyrinchus and preliminary study of the hydrodynamic behaviour through computational fluid dynamics.

    PubMed

    Díez, G; Soto, M; Blanco, J M

    2015-07-01

    This study characterized the morphology, density and orientation of the dermal denticles along the body of a shortfin mako shark Isurus oxyrinchus and identified the hydrodynamic parameters of its body through a computational fluid-dynamics model. The study showed a great variability in the morphology, size, shape, orientation and density of dermal denticles along the body of I. oxyrinchus. There was a significant higher density in dorsal and ventral areas of the body and their highest angular deviations were found in the lower part of the mouth and in the areas between the pre-caudal pit and the second dorsal and pelvic fins. A detailed three-dimensional geometry from a scanned body of a shark was carried out to evaluate the hydrodynamic properties such as drag coefficient, lift coefficient and superficial (skin) friction coefficient of the skin together with flow velocity field, according to different roughness coefficients simulating the effect of the dermal denticles. This preliminary approach contributed to detailed information of the denticle interactions. As the height of the denticles was increased, flow velocity and the effect of lift decreased whereas drag increased. The highest peaks of skin friction coefficient were observed around the pectoral fins. PMID:26044174

  9. Hemodynamic analysis of renal artery stenosis using computational fluid dynamics technology based on unenhanced steady-state free precession magnetic resonance angiography: preliminary results.

    PubMed

    Zhang, Weisheng; Qian, Yi; Lin, Jiang; Lv, Peng; Karunanithi, Kaavya; Zeng, Mengsu

    2014-02-01

    This study aims to evaluate the feasibility of computational fluid dynamics (CFD) technology in analysis of renal artery stenosis (RAS) based on unenhanced MR angiography (MRA). Thirty hypertensive patients with unilateral RAS, and 10 normal volunteers, underwent unenhanced MRA on a 1.5 T MR scanner. 12 of 30 patients also underwent ultrasound (US) to detect peak systolic velocity. The patient-specific CFD based on MRA was carried out thereafter. Stenosis grades and hemodynamic variables at the stenosis of main renal artery, including pressure difference (PD), velocity and mass flow rate (MFR), were analysed. And the hemodynamic indices of stenoses were compared with the parameters of normal renal arteries and available US velocity profile. High intraclass correlation coefficient (value 0.995) and no significant difference (p > 0.05) was shown between maximum velocity of CFD and peak systolic velocity of US in 12 patients. For normal renal arteries, the average PD, velocity and MFR were all in the reported normal physiological range. However, for stenotic arteries, the translesional PD and velocity of main renal arteries increased with the severity of stenotic degrees, while the MFR decreased. 50 % diameter stenosis was the threshold at which all three hemodynamic parameters experienced significant changes (p < 0.01). This preliminary study shows that unenhanced-MRA-based CFD can be utilized to noninvasively analyse hemodynamic parameters of RAS. The acquired variables may provide meaningful information regarding stratification of the stenosis and further therapeutic treatment. PMID:24318538

  10. On-line computer system to minimize laser injuries during surgery: preliminary system layout and proposal of the key features.

    PubMed

    Canestri, F

    1999-01-01

    The aim of this paper is to investigate some new user interface ideas and related application packages which aim to improve the degree of safety in an operating room during surgical operations in which an invasive laser beam is deployed. The overall value of the proposition is that a means is provided which ensures the successful completion of the surgical case while minimizing the risk of thermal and mechanical injuries to healthy tissues adjacent to the surgical field. According to surgeons operating with a variety of CO2 lasers available at both the National Cancer Institute in Milan, Italy, and the Sackler School of Medicine, Tel Aviv University, Israel, each laser device presents different cutting and coagulation properties. In order to identify which 'ideal' procedure might corroborate the subjective impression of each surgeon and also to provide one common tool to ensure procedures with a high level of safety, the author has worked for several months with surgeons and technicians of both Institutions to define the general design of a new on-line surgical operation planning and design system to be used during the pre-operative briefing activities and also as a consultation tool during operation. This software package will be developed and tested on both 'C' and FORTRAN compilers running on a commercially available PC which is driving a continuous wave (CW) CO2 laser device via its Instrument Bus interface. The present proposal describes the details of a software package called LCA (Laser-beam Controller and Adviser) which performs several controls in parallel on the key output parameters of a laser beam device during its utilization in delicate surgical operations. The required performances of this device needed during a given surgical operation are pre-simulated and compared against the well-known safety limits, which are stored in the computer's mass storage. If the surgeon's decision about the laser device set-up are considered to be too close to the

  11. Computer simulations of large asteroid impacts into oceanic and continental sites--preliminary results on atmospheric, cratering and ejecta dynamics

    USGS Publications Warehouse

    Roddy, D.J.; Schuster, S.H.; Rosenblatt, M.; Grant, L.B.; Hassig, P.J.; Kreyenhagen, K.N.

    1987-01-01

    Computer simulations have been completed that describe passage of a 10-km-diameter asteroid through the Earth's atmosphere and the subsequent cratering and ejecta dynamics caused by impact of the asteroid into both oceanic and continental sites. The asteroid was modeled as a spherical body moving vertically at 20 km/s with a kinetic energy of 2.6 ?? 1030 ergs (6.2 ?? 107 Mt ). Detailed material modeling of the asteroid, ocean, crustal units, sedimentary unit, and mantle included effects of strength and fracturing, generic asteroid and rock properties, porosity, saturation, lithostatic stresses, and geothermal contributions, each selected to simulate impact and geologic conditions that were as realistic as possible. Calculation of the passage of the asteroid through a U.S. Standard Atmosphere showed development of a strong bow shock wave followed by a highly shock compressed and heated air mass. Rapid expansion of this shocked air created a large low-density region that also expanded away from the impact area. Shock temperatures in air reached ???20,000 K near the surface of the uplifting crater rim and were as high as ???2000 K at more than 30 km range and 10 km altitude. Calculations to 30 s showed that the shock fronts in the air and in most of the expanding shocked air mass preceded the formation of the crater, ejecta, and rim uplift and did not interact with them. As cratering developed, uplifted rim and target material were ejected into the very low density, shock-heated air immediately above the forming crater, and complex interactions could be expected. Calculations of the impact events showed equally dramatic effects on the oceanic and continental targets through an interval of 120 s. Despite geologic differences in the targets, both cratering events developed comparable dynamic flow fields and by ???29 s had formed similar-sized transient craters ???39 km deep and ???62 km across. Transient-rim uplift of ocean and crust reached a maximum altitude of nearly

  12. Development and preliminary user testing of the DCIDA (Dynamic computer interactive decision application) for ‘nudging’ patients towards high quality decisions

    PubMed Central

    2014-01-01

    Background Patient decision aids (PtDA) are developed to facilitate informed, value-based decisions about health. Research suggests that even when informed with necessary evidence and information, cognitive errors can prevent patients from choosing the option that is most congruent with their own values. We sought to utilize principles of behavioural economics to develop a computer application that presents information from conventional decision aids in a way that reduces these errors, subsequently promoting higher quality decisions. Method The Dynamic Computer Interactive Decision Application (DCIDA) was developed to target four common errors that can impede quality decision making with PtDAs: unstable values, order effects, overweighting of rare events, and information overload. Healthy volunteers were recruited to an interview to use three PtDAs converted to the DCIDA on a computer equipped with an eye tracker. Participants were first used a conventional PtDA, and then subsequently used the DCIDA version. User testing was assessed based on whether respondents found the software both usable: evaluated using a) eye-tracking, b) the system usability scale, and c) user verbal responses from a ‘think aloud’ protocol; and useful: evaluated using a) eye-tracking, b) whether preferences for options were changed, and c) and the decisional conflict scale. Results Of the 20 participants recruited to the study, 11 were male (55%), the mean age was 35, 18 had at least a high school education (90%), and 8 (40%) had a college or university degree. Eye-tracking results, alongside a mean system usability scale score of 73 (range 68–85), indicated a reasonable degree of usability for the DCIDA. The think aloud study suggested areas for further improvement. The DCIDA also appeared to be useful to participants wherein subjects focused more on the features of the decision that were most important to them (21% increase in time spent focusing on the most important feature

  13. SUPER-RESOLUTION ULTRASOUND TOMOGRAPHY: A PRELIMINARY STUDY WITH A RING ARRAY

    SciTech Connect

    HUANG, LIANJIE; SIMONETTI, FRANCESCO; DURIC, NEBOJSA; RAMA, OLSI

    2007-01-18

    Ultrasound tomography attempts to retrieve the structure of an objective by exploiting the interaction of acoustic waves with the object. A fundamental limit of ultrasound tomography is that features cannot be resolved if they are spaced less than {lambda}/2 apart, where {lambda} is wavelength of the probing wave, regardless of the degree of accuracy of the measurements. Therefore, since the attenuation of the probing wave with propagation distance increases as {lambda} decreases, resolution has to be traded against imaging depth. Recently, it has been shown that the {lambda}/2 limit is a consequence of the Born approximation (implicit in the imaging algorithms currently employed) which neglects the distortion of the probing wavefield as it travels through the medium to be imaged. On the other hand, such a distortion, which is due to the multiple scattering phenomenon, can encode unlimited resolution in the radiating component of the scattered field. Previously, a resolution better than {lambda}/3 has been reported in these proceedings [F. Simonetti, pp. 126 (2006)] in the case of elastic wave probing. In this paper, they demonstrate experimentally a resolution better than {lambda}/4 for objects immersed in a water bth probed by means of a ring array which excites and detects pressure waves in a full view configuration.

  14. Prospective computer-assisted voice analysis for patients with early stage glottic cancer: A preliminary report of the functional result of laryngeal irradiation

    SciTech Connect

    Harrison, L.B.; Solomon, B.; Miller, S.; Fass, D.E.; Armstrong, J.; Sessions, R.B. )

    1990-07-01

    In January 1987 we began a prospective study aimed at evaluating objective parameters of vocal function for all patients treated with RT for early glottic cancer. All patients underwent vocal analysis using a voice analyzer interfaced with a computer. This allowed for the determination of percent voicing (%V) (normal = presence of phonation = 90-100%V). Other parameters such as breathiness and strain were also measured. Patients were recorded before RT, weekly during RT, and at set intervals after RT. There have been 25 patients studied. Eighteen (18) are evaluable at 9 months after treatment. All patients were male and ranged from 45-84 years old. Fourteen (14) and T1 lesions and received 66 GY/33 fractions to their larynx and 4 had T2 tumors and received 66-70 Gy/33-35 fractions. To date, all patients are locally controlled. Three distinct patterns of %V changes have been encountered. However, all patients demonstrated normal phonation pattern by 3 months after RT, and this is sustained at 9 months follow-up. In addition, 94% of patients have had significant decrease in breathiness after RT, which objectively documents diminished hoarseness. In 83%, breathiness is normal after RT. Most patients have had increased strain after RT, which documents increased vocal cord tension. However, strain remained within normal limits in 89%. Our preliminary analysis suggests that the majority of patients irradiated for early glottic cancer demonstrate a decrease in breathiness and an increase in strain after RT, and enjoy a resultant voice that has normal phonation maintained at 9 months after RT. Our data also demonstrate three distinct phonation patterns. Further follow-up will allow us to determine the prognostic significance, if any, of these patterns, and to continue to follow objective vocal parameters on larger numbers of patient.

  15. Prospective computer-assisted voice analysis for patients with early stage glottic cancer: a preliminary report of the functional result of laryngeal irradiation.

    PubMed

    Harrison, L B; Solomon, B; Miller, S; Fass, D E; Armstrong, J; Sessions, R B

    1990-07-01

    In January 1987 we began a prospective study aimed at evaluating objective parameters of vocal function for all patients treated with RT for early glottic cancer. All patients underwent vocal analysis using a voice analyzer interfaced with a computer. This allowed for the determination of percent voicing (%V) (normal = presence of phonation = 90-100%V). Other parameters such as breathiness (air turbulence or hoarseness) and strain (vocal cord tension) were also measured. Patients were recorded before RT, weekly during RT, and at set intervals after RT. There have been 25 patients studied. Eighteen (18) are evaluable at 9 months after treatment. All patients were male and ranged from 45-84 years old. Fourteen (14) and T1 lesions and received 66 GY/33 fractions to their larynx and 4 had T2 tumors and received 66-70 Gy/33-35 fractions. To date, all patients are locally controlled. Three distinct patterns of %V changes have been encountered. However, all patients demonstrated normal phonation pattern by 3 months after RT, and this is sustained at 9 months follow-up. In addition, 94% of patients have had significant decrease in breathiness after RT, which objectively documents diminished hoarseness. In 83%, breathiness is normal after RT. Most patients have had increased strain after RT, which documents increased vocal cord tension. However, strain remained within normal limits in 89%. Our preliminary analysis suggests that the majority of patients irradiated for early glottic cancer demonstrate a decrease in breathiness and an increase in strain after RT, and enjoy a resultant voice that has normal phonation maintained at 9 months after RT. Our data also demonstrate three distinct phonation patterns. Further follow-up will allow us to determine the prognostic significance, if any, of these patterns, and to continue to follow objective vocal parameters on larger numbers of patient. PMID:2380077

  16. SU-E-I-74: Image-Matching Technique of Computed Tomography Images for Personal Identification: A Preliminary Study Using Anthropomorphic Chest Phantoms

    SciTech Connect

    Matsunobu, Y; Shiotsuki, K; Morishita, J

    2015-06-15

    Purpose: Fingerprints, dental impressions, and DNA are used to identify unidentified bodies in forensic medicine. Cranial Computed tomography (CT) images and/or dental radiographs are also used for identification. Radiological identification is important, particularly in the absence of comparative fingerprints, dental impressions, and DNA samples. The development of an automated radiological identification system for unidentified bodies is desirable. We investigated the potential usefulness of bone structure for matching chest CT images. Methods: CT images of three anthropomorphic chest phantoms were obtained on different days in various settings. One of the phantoms was assumed to be an unidentified body. The bone image and the bone image with soft tissue (BST image) were extracted from the CT images. To examine the usefulness of the bone image and/or the BST image, the similarities between the two-dimensional (2D) or threedimensional (3D) images of the same and different phantoms were evaluated in terms of the normalized cross-correlation value (NCC). Results: For the 2D and 3D BST images, the NCCs obtained from the same phantom assumed to be an unidentified body (2D, 0.99; 3D, 0.93) were higher than those for the different phantoms (2D, 0.95 and 0.91; 3D, 0.89 and 0.80). The NCCs for the same phantom (2D, 0.95; 3D, 0.88) were greater compared to those of the different phantoms (2D, 0.61 and 0.25; 3D, 0.23 and 0.10) for the bone image. The difference in the NCCs between the same and different phantoms tended to be larger for the bone images than for the BST images. These findings suggest that the image-matching technique is more useful when utilizing the bone image than when utilizing the BST image to identify different people. Conclusion: This preliminary study indicated that evaluating the similarity of bone structure in 2D and 3D images is potentially useful for identifying of an unidentified body.

  17. Differentiating Small (≤1 cm) Focal Liver Lesions as Metastases or Cysts by means of Computed Tomography: A Case-Study to Illustrate a Fuzzy Logic-Based Method to Assess the Impact of Diagnostic Confidence on Radiological Diagnosis

    PubMed Central

    Zanella, Gloria; Pullini, Serena; Como, Giuseppe; Bazzocchi, Massimo

    2014-01-01

    Purpose. To quantify the impact of diagnostic confidence on radiological diagnosis with a fuzzy logic-based method. Materials and Methods. Twenty-two oncologic patients with 20 cysts and 30 metastases ≤1 cm in size found at 64-row computed tomography were included. Two readers (R1/R2) expressed diagnoses as a subjective level of confidence P(d) in malignancy within the interval [0,1] rather than on a “crisp” basis (malignant/benign); confidence in benignancy was 1 − p(d). When cross-tabulating data according to the standard of reference, 2 × 2 table cells resulted from the aggregation between p(d)/1 − p(d) and final diagnosis. We then assessed (i) readers diagnostic performance on a fuzzy and crisp basis; (ii) the “divergence” δ(F, C) (%) as a measure of how confidence impacted on crisp diagnosis. Results. Diagnoses expressed with lower confidence increased fuzzy false positives compared to crisp ones (from 0 to 0.2 for R1; from 1 to 2.4 for R2). Crisp/fuzzy accuracy was 94.0%/93.6% (R1) and 94.0/91.6% (R2). δ(F, C) (%) was larger in the case of the less experienced reader (R2) (up to +7.95% for specificity). According to simulations, δ(F, C) (%) was negative/positive depending on the level of confidence in incorrect diagnoses. Conclusion. Fuzzy evaluation shows a measurable effect of uncertainty on radiological diagnoses. PMID:24587815

  18. The Use of Computer Assistance in Curriculum Planning. A Report of the Curriculum and Timetable Strategies Preliminary Research Project, 1976-1978.

    ERIC Educational Resources Information Center

    Pratt, Simon

    This experiment in using computer-assisted curriculum planning in two British secondary schools tested the practicability of using computers not only in the annual compilation of school timetables but, more radically, in the characterization of constraints that "knock-on" from one year's timetable to the next. The Oxford School Timetabling System…

  19. Anatomical optical coherence tomography: a safe and effective tool for quantitative long-term monitoring of upper airway size and shape

    NASA Astrophysics Data System (ADS)

    Armstrong, J. J.; Becker, S.; McLaughlin, R. A.; Leigh, M. S.; Williamson, J.; Walsh, J. H.; Hillman, D. R.; Eastwood, P. R.; Sampson, D. D.

    2008-02-01

    Anatomical optical coherence tomography (aOCT) is an endoscopic optical technique that enables continuous, quantitative assessment of hollow organ size and shape in three dimensions. It is a powerful alternative to X-ray computed tomography, magnetic resonance imaging, and video endoscopy for the assessment of gross hollow-organ anatomy. This paper reviews our instrument and its application to the upper and lower airway, and includes a number of new results.

  20. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D

    2010-11-23

    The American College of Cardiology Foundation, along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research. PMID:20975004

  1. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D; Kramer, Christopher M; Berman, Daniel; Brown, Alan; Chaudhry, Farooq A; Cury, Ricardo C; Desai, Milind Y; Einstein, Andrew J; Gomes, Antoinette S; Harrington, Robert; Hoffmann, Udo; Khare, Rahul; Lesser, John; McGann, Christopher; Rosenberg, Alan; Schwartz, Robert; Shelton, Marc; Smetana, Gerald W; Smith, Sidney C

    2010-11-23

    The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research. PMID:21087721

  2. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D

    2010-01-01

    The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research. PMID:21232696

  3. Preliminary considerations for the computer analysis of fringe maps generated when holographic interferometry is applied as an NDT tool for airframe structures

    NASA Astrophysics Data System (ADS)

    Mew, Jacqueline M.; Webster, John M.; Hand, Steve; Schmidt, Timothy E.

    1998-09-01

    The temptation when presented with the requirement to interpret holographic interferograms of aluminum aircraft structures derived through a non-destructive testing technique is to examine the whole interferogram. Computers are renowned for their ability to process large amounts of data accurately and speedily, therefore there is a strong temptation to harness their particular powers. This is not only time-consuming and wasteful of computing resources, it is also unnecessary. However, before work can begin on interpreting an interferogram by computer the problem itself must be defined. In this particular example the interferogram is from a sample taken from one of the world's aging passenger airline fleet. The sample is from an aluminum stabilizer in which faults have been induced or have occurred during the service lifetime of the aircraft. All faults have been confirmed by destructive evaluation or by alternative techniques. Thus the problem domain is known. When a human expert examines an interferogram s/he concentrates on areas where faults are likely to occur namely, the areas immediately surrounding the stringers and frames as well as the stringers and frames themselves. The faults are typically caused through endless pressurization cycles or through corrosion. These faults have been induced to show themselves by a distinctive pattern of interference fringes across stringers and frames, where normally no fringes should be expected to occur. Therefore the human expert search concentrates on these areas, using the fringe count density or shape over the whole of the interferogram simply for comparison or control. The computer aims to emulate the human search. However, difficulties have been identified that could prove problematic for the computer that are elementary for the human brain. In our early work the sample interferograms for computer analysis have been selected because, to a human, they are uncomplicated and relatively noise-free sample in which faults

  4. Computer-Enhanced Interventions for Drug Use and HIV Risk in the Emergency Room: Preliminary Results on Psychological Precursors of Behavior Change

    PubMed Central

    Bonar, Erin E.; Walton, Maureen A.; Cunningham, Rebecca M.; Chermack, Stephen T.; Bohnert, Amy S.B.; Barry, Kristen L.; Booth, Brenda M.; Blow, Frederic C.

    2013-01-01

    This paper describes process data from a randomized controlled trial among 781 adults recruited in the Emergency Department who reported recent drug use and were randomized to: intervener-delivered brief intervention (IBI) assisted by computer, computerized BI (CBI), or enhanced usual care (EUC). Analyses examined differences between baseline and post-intervention on psychological constructs theoretically related to changes in drug use and HIV risk: importance, readiness, intention, help-seeking, and confidence. Compared to EUC, participants receiving the IBI significantly increased in confidence and intentions; CBI patients increased importance, readiness, confidence, and help-seeking. Both groups increased relative to the EUC in likelihood of condom use with regular partners. Examining BI components suggested that benefits of change and tools for change were associated with changes in psychological constructs. Delivering BIs targeting drug use and HIV risk using computers appears promising for implementation in healthcare settings. This trial is ongoing and future work will report behavioral outcomes. PMID:24035142

  5. A web-based remote radiation treatment planning system using the remote desktop function of a computer operating system: a preliminary report.

    PubMed

    Suzuki, Keishiro; Hirasawa, Yukinori; Yaegashi, Yuji; Miyamoto, Hideki; Shirato, Hiroki

    2009-01-01

    We developed a web-based, remote radiation treatment planning system which allowed staff at an affiliated hospital to obtain support from a fully staffed central institution. Network security was based on a firewall and a virtual private network (VPN). Client computers were installed at a cancer centre, at a university hospital and at a staff home. We remotely operated the treatment planning computer using the Remote Desktop function built in to the Windows operating system. Except for the initial setup of the VPN router, no special knowledge was needed to operate the remote radiation treatment planning system. There was a time lag that seemed to depend on the volume of data traffic on the Internet, but it did not affect smooth operation. The initial cost and running cost of the system were reasonable. PMID:19948709

  6. An Overview of Preliminary Computational and Experimental Results for the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Perry, Boyd, III; Florance, James R.; Sanetrik, Mark D.; Wieseman, Carol D.; Stevens, William L.; Funk, Christie J.; Hur, Jiyoung; Christhilf, David M.; Coulson, David A.

    2011-01-01

    A summary of computational and experimental aeroelastic and aeroservoelastic (ASE) results for the Semi-Span Super-Sonic Transport (S4T) wind-tunnel model is presented. A broad range of analyses and multiple ASE wind-tunnel tests of the S4T have been performed in support of the ASE element in the Supersonics Program, part of NASA's Fundamental Aeronautics Program. The computational results to be presented include linear aeroelastic and ASE analyses, nonlinear aeroelastic analyses using an aeroelastic CFD code, and rapid aeroelastic analyses using CFD-based reduced-order models (ROMs). Experimental results from two closed-loop wind-tunnel tests performed at NASA Langley's Transonic Dynamics Tunnel (TDT) will be presented as well.

  7. Computed Tomography Versus Magnetic Resonance Imaging-Based Contouring in Cervical Cancer Brachytherapy: Results of a Prospective Trial and Preliminary Guidelines for Standardized Contours

    SciTech Connect

    Viswanathan, Akila N.; Dimopoulos, Johannes . E-mail: Johannes.dimopoulos@akhwien.at; Kirisits, Christian; Berger, Daniel; Poetter, Richard

    2007-06-01

    Purpose: To compare the contours and dose-volume histograms (DVH) of the tumor and organs at risk (OAR) with computed tomography (CT) vs. magnetic resonance imaging (MRI) in cervical cancer brachytherapy. Methods and Materials: Ten patients underwent both MRI and CT after applicator insertion. The dose received by at least 90% of the volume (D{sub 90}), the minimal target dose (D{sub 100}), the volume treated to the prescription dose or greater for tumor for the high-risk (HR) and intermediate-risk (IR) clinical target volume (CTV) and the dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} for the OARs were evaluated. A standardized approach to contouring on CT (CT{sub Std}) was developed, implemented (HR- and IR-CTV{sub CTStd}), and compared with the MRI contours. Results: Tumor height, thickness, and total volume measurements, as determined by either CT or CT{sub Std} were not significantly different compared with the MRI volumes. In contrast, the width measurements differed in HR-CTV{sub CTStd} (p = 0.05) and IR-CTV{sub CTStd} (p = 0.01). For the HR-CTV{sub CTStd}, this resulted in statistically significant differences in the volume treated to the prescription dose or greater (MRI, 96% vs. CT{sub Std}, 86%, p = 0.01), D{sub 100} (MRI, 5.4 vs. CT{sub Std}, 3.4, p <0.01), and D{sub 90} (MRI, 8.7 vs. CT{sub Std}, 6.7, p <0.01). Correspondingly, the IR-CTV DVH values on MRI vs. CT{sub Std}, differed in the D{sub 100} (MRI, 3.0 vs. CT{sub Std}, 2.2, p = 0.01) and D{sub 90} (MRI, 5.6 vs. CT{sub Std}, 4.6, p = 0.02). The MRI and CT DVH values of the dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} for the OARs were similar. Conclusion: Computed tomography-based or MRI-based scans at brachytherapy are adequate for OAR DVH analysis. However, CT tumor contours can significantly overestimate the tumor width, resulting in significant differences in the D{sub 90}, D{sub 100}, and volume treated to the prescription dose or greater for the HR-CTV compared with that using

  8. Effects of brain-computer interface-based functional electrical stimulation on balance and gait function in patients with stroke: preliminary results

    PubMed Central

    Chung, EunJung; Park, Sang-In; Jang, Yun-Yung; Lee, Byoung-Hee

    2015-01-01

    [Purpose] The purpose of this study was to determine the effects of brain-computer interface (BCI)-based functional electrical stimulation (FES) on balance and gait function in patients with stroke. [Subjects] Subjects were randomly allocated to a BCI-FES group (n=5) and a FES group (n=5). [Methods] The BCI-FES group received ankle dorsiflexion training with FES according to a BCI-based program for 30 minutes per day for 5 days. The FES group received ankle dorsiflexion training with FES for the same duration. [Results] Following the intervention, the BCI-FES group showed significant differences in Timed Up and Go test value, cadence, and step length on the affected side. The FES group showed no significant differences after the intervention. However, there were no significant differences between the 2 groups after the intervention. [Conclusion] The results of this study suggest that BCI-based FES training is a more effective exercise for balance and gait function than FES training alone in patients with stroke. PMID:25729205

  9. Comparison of Contrast-Enhanced Ultrasound and Computed Tomography in Classifying Endoleaks After Endovascular Treatment of Abdominal Aorta Aneurysms: Preliminary Experience

    SciTech Connect

    Carrafiello, Gianpaolo Lagana, Domenico; Recaldini, Chiara; Mangini, Monica; Bertolotti, Elena; Caronno, Roberto; Tozzi, Matteo; Piffaretti, Gabriele; Annibale Genovese, Eugenio; Fugazzola, Carlo

    2006-12-15

    The purpose of the study was to assess the effectiveness of contrast-enhanced ultrasonography (CEUS) in endoleak classification after endovascular treatment of an abdominal aortic aneurysm compared to computed tomography angiography (CTA). From May 2001 to April 2003, 10 patients with endoleaks already detected by CTA underwent CEUS with Sonovue (registered) to confirm the CTA classification or to reclassify the endoleak. In three conflicting cases, the patients were also studied with conventional angiography. CEUS confirmed the CTA classification in seven cases (type II endoleaks). Two CTA type III endoleaks were classified as type II using CEUS and one CTA type II endoleak was classified as type I by CEUS. Regarding the cases with discordant classification, conventional angiography confirmed the ultrasound classification. Additionally, CEUS documented the origin of type II endoleaks in all cases. After CEUS reclassification of endoleaks, a significant change in patient management occurred in three cases. CEUS allows a better attribution of the origin of the endoleak, as it shows the flow in real time. CEUS is more specific than CTA in endoleak classification and gives more accurate information in therapeutic planning.

  10. Analysis of vector models in quantification of artifacts produced by standard prosthetic inlays in Cone-Beam Computed Tomography (CBCT)--a preliminary study.

    PubMed

    Różyło-Kalinowska, Ingrid; Miechowicz, Sławomir; Sarna-Boś, Katarzyna; Borowicz, Janusz; Kalinowski, Paweł

    2014-01-01

    Cone-beam computed tomography (CBCT) is a relatively new, but highly efficient imaging method applied first in dentistry in 1998. However, the quality of the obtained slices depends among other things on artifacts generated by dental restorations as well as orthodontic and prosthetic appliances. The aim of the study was to quantify the artifacts produced by standard prosthetic inlays in CBCT images. The material consisted of 17 standard prosthetic inlays mounted in dental roots embedded in resin. The samples were examined by means of a large field of view CBCT unit, Galileos (Sirona, Germany), at 85 kV and 14 mAs. The analysis was performed using Able 3DDoctor software for data in the CT raster space as well as by means of Materialise Magics software for generated vector models (STL). The masks generated in the raster space included the area of the inlays together with image artifacts. The region of interest (ROI) of the raster space is a set of voxels from a selected range of Hounsfield units (109-3071). Ceramic inlay with zirconium dioxide (Cera Post) as well as epoxy resin inlay including silica fibers enriched with zirconium (Easy Post) produced the most intense artifacts. The smallest image distortions were created by titanium inlays, both passive (Harald Nordin) and active (Flexi Flange). Inlays containing zirconium generated the strongest artifacts, thus leading to the greatest distortions in the CBCT images. Carbon fiber inlay did not considerably affect the image quality. PMID:25404623

  11. Numerical computation of gravitational field of infinitely thin axisymmetric disc with arbitrary surface mass density profile and its application to preliminary study of rotation curve of M33

    NASA Astrophysics Data System (ADS)

    Fukushima, Toshio

    2016-03-01

    We developed a numerical method to compute the gravitational field of an infinitely thin axisymmetric disc with an arbitrary surface mass density profile. We evaluate the gravitational potential by a split quadrature using the double exponential rule and obtain the acceleration vector by numerically differentiating the potential by Ridder's algorithm. The new method is of around 12 digit accuracy and sufficiently fast because requiring only one-dimensional integration. By using the new method, we show the rotation curves of some non-trivial discs: (i) truncated power-law discs, (ii) discs with a non-negligible centre hole, (iii) truncated Mestel discs with edge softening, (iv) double power-law discs, (v) exponentially damped power-law discs, and (vi) an exponential disc with a sinusoidal modulation of the density profile. Also, we present a couple of model fittings to the observed rotation curve of M33: (i) the standard deconvolution by assuming a spherical distribution of the dark matter and (ii) a direct fit of infinitely thin disc mass with a double power-law distribution of the surface mass density. Although the number of free parameters is a little larger, the latter model provides a significantly better fit. The FORTRAN 90 programs of the new method are electronically available.

  12. Mosaic tile model to compute gravitational field for infinitely thin non axisymmetric objects and its application to preliminary analysis of gravitational field of M74

    NASA Astrophysics Data System (ADS)

    Fukushima, Toshio

    2016-04-01

    Using the analytical expressions of the Newtonian gravitational potential and the associated acceleration vector for an infinitely thin uniform rectangular plate, we developed a method to compute the gravitational field of a general infinitely thin object without assuming its axial symmetry when its surface mass density is known at evenly spaced rectangular grid points. We utilized the method in evaluating the gravitational field of the HI gas, dust, red stars, and blue stars components of M74 from its THINGS, 2MASS, PDSS1, and GALEX data. The non axisymmetric feature of M74 including an asymmetric spiral structure is seen from (i) the contour maps of the determined gravitational potential, (ii) the vector maps of the associated acceleration vector, and (iii) the cross section views of the gravitational field and the surface mass density along different directions. An x-mark pattern in the gravitational field is detected at the core of M74 from the analysis of its dust and red stars components. Meanwhile, along the east-west direction in the central region of the angular size of 1', the rotation curve derived from the radial component of the acceleration vector caused by the red stars component matches well with that observed by the VENGA project. Thus the method will be useful in studying the dynamics of particles and fluids near and inside spiral galaxies with known photometry data. Electronically available are the table of the determined gravitational fields of M74 on its galactic plane as well as the Fortran 90 programs to produce them.

  13. Mosaic tile model to compute gravitational field for infinitely thin non-axisymmetric objects and its application to preliminary analysis of gravitational field of M74

    NASA Astrophysics Data System (ADS)

    Fukushima, Toshio

    2016-07-01

    Using the analytical expressions of the Newtonian gravitational potential and the associated acceleration vector for an infinitely thin uniform rectangular plate, we developed a method to compute the gravitational field of a general infinitely thin object without assuming its axial symmetry when its surface mass density is known at evenly spaced rectangular grid points. We utilized the method in evaluating the gravitational field of the H I gas, dust, red stars, and blue stars components of M74 from its THINGS, 2MASS, PDSS1, and GALEX data. The non-axisymmetric feature of M74 including an asymmetric spiral structure is seen from (i) the contour maps of the determined gravitational potential, (ii) the vector maps of the associated acceleration vector, and (iii) the cross-section views of the gravitational field and the surface mass density along different directions. An x-mark pattern in the gravitational field is detected at the core of M74 from the analysis of its dust and red stars components. Meanwhile, along the east-west direction in the central region of the angular size of 1 arcmin, the rotation curve derived from the radial component of the acceleration vector caused by the red stars component matches well with that observed by the VENGA project. Thus the method will be useful in studying the dynamics of particles and fluids near and inside spiral galaxies with known photometry data. Electronically available are the table of the determined gravitational fields of M74 on its galactic plane as well as the FORTRAN 90 programs to produce them.

  14. Optimizing Hybrid Occlusion in Face-Jaw-Teeth Transplantation: A Preliminary Assessment of Real-Time Cephalometry as Part of the Computer-Assisted Planning and Execution Workstation for Craniomaxillofacial Surgery

    PubMed Central

    Murphy, Ryan J.; Basafa, Ehsan; Hashemi, Sepehr; Grant, Gerald T.; Liacouras, Peter; Susarla, Srinivas M.; Otake, Yoshito; Santiago, Gabriel; Armand, Mehran; Gordon, Chad R.

    2016-01-01

    Background The aesthetic and functional outcomes surrounding Le Fort–based, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and “hybrid malocclusion.” Therefore, a novel technology—real-time cephalometry—was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Methods Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Results Compared with postoperative data, the real-time cephalometry–calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Conclusion Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring “hybrid occlusion” in face-jaw-teeth transplantation and other orthognathic surgical procedures. PMID:26218382

  15. Preliminary experience on the implementation of computed tomography (CT)-based image guided brachytherapy (IGBT) of cervical cancer using high-dose-rate (HDR) Cobalt-60 source in University of Malaya Medical Centre (UMMC)

    NASA Astrophysics Data System (ADS)

    Jamalludin, Z.; Min, U. N.; Ishak, W. Z. Wan; Malik, R. Abdul

    2016-03-01

    This study presents our preliminary work of the computed tomography (CT) image guided brachytherapy (IGBT) implementation on cervical cancer patients. We developed a protocol in which patients undergo two Magnetic Resonance Imaging (MRI) examinations; a) prior to external beam radiotherapy (EBRT) and b) prior to intra-cavitary brachytherapy for tumour identification and delineation during IGBT planning and dosimetry. For each fraction, patients were simulated using CT simulator and images were transferred to the treatment planning system. The HR-CTV, IR-CTV, bladder and rectum were delineated on CT-based contouring for cervical cancer. Plans were optimised to achieve HR-CTV and IR-CTV dose (D90) of total EQD2 80Gy and 60Gy respectively, while limiting the minimum dose to the most irradiated 2cm3 volume (D2cc) of bladder and rectum to total EQD2 90Gy and 75Gy respectively. Data from seven insertions were analysed by comparing the volume-based with traditional point- based doses. Based on our data, there were differences between volume and point doses of HR- CTV, bladder and rectum organs. As the number of patients having the CT-based IGBT increases from day to day in our centre, it is expected that the treatment and dosimetry accuracy will be improved with the implementation.

  16. Preliminary Report: Results of Computed Tracer Concentrations over Eastern China, South Korea, and Japan for 01 March to 30 May 2007 Daily Simulated Releases from Taiyuan, China

    SciTech Connect

    Vogt, P

    2007-08-07

    In order to prepare for a proposed long range tracer experiment in China for the spring of 2008 time period, NARAC computed hypothetical PMCH concentrations over Eastern China, South Korea and Japan for simulated releases from Taiyuan, China. Normalized 1 kg of PMCH source strength releases were made twice a day, with wind input from global forecast weather model. We used 6-hour analysis fields valid at the start of each model run, resulting in four wind fields per day. The selected domain encompassed the region of interest over eastern Asia and the Western Pacific. Screening runs were made for each day at 0000 and 1200 UTC from 01 April, 2007 through 29 May, 2007 for a total of 90 days and 180 cases. 24-hour average air concentrations were evaluated at 22 sample cities in the three regions of interest for each case. 15 sample cities were selected to help quantify modeling results for experiment objectives. Any case that resulted in model predicted air concentrations exceeding 2.0E-02 fL/L at a sample city in all three regions was then selected for a detailed model run with source times six hours before and after evaluated in addition to the case time. The detailed runs used the same wind fields and model domain, but 6-hour average air concentrations were generated and analyzed for the 15 sample cities. Each of the 180 cases were ranked subjectively, based on whether or not the model prediction indicated the possibility that a release on that date and time might achieve the long range experiment objectives. Ranks used are High, Good, Low, Poor, and Bad. Of the 180 cases run, NARAC dispersion models predicted 6 instances of High possibility, 8 cases of Good, 32 of Low, 74 of Poor, and 60 cases of Bad probability. Detailed model runs were made for all 14 High or Good probability cases, a total of only 7.8% of all analyzed. Based on the results of this study we have identified a few dates on which a release of a reasonable amount of PMCH tracer (on the order of 500 kg

  17. A Preliminary Jupiter Model

    NASA Astrophysics Data System (ADS)

    Hubbard, W. B.; Militzer, B.

    2016-03-01

    In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen-helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses and a hydrogen-helium-rich envelope with approximately three times solar metallicity.

  18. Computer Guided Instructional Design.

    ERIC Educational Resources Information Center

    Merrill, M. David; Wood, Larry E.

    1984-01-01

    Describes preliminary efforts to create the Lesson Design System, a computer-guided instructional design system written in Pascal for Apple microcomputers. Its content outline, strategy, display, and online lesson editors correspond roughly to instructional design phases of content and strategy analysis, display creation, and computer programing…

  19. Neuroanatomy of cranial computed tomography

    SciTech Connect

    Kretschmann, H.J.; Weinrich, W.

    1985-01-01

    Based on the fundamental structures visualized by means of computed tomography, the authors present the functional systems which are relevant in neurology by means of axial cross-sections. All drawings were prepared from original preparations by means of a new technique which is similar to the grey values of X-ray CT and nuclear magnetic resonance tomography. A detailed description is given of the topics of neurofunctional lesions.

  20. Preliminary DIAL model

    SciTech Connect

    Gentry, S.; Taylor, J.; Stephenson, D.

    1994-06-01

    A unique end-to-end LIDAR sensor model has been developed supporting the concept development stage of the CALIOPE UV DIAL and UV laser-induced-fluorescence (LIF) efforts. The model focuses on preserving the temporal and spectral nature of signals as they pass through the atmosphere, are collected by the optics, detected by the sensor, and processed by the sensor electronics and algorithms. This is done by developing accurate component sub-models with realistic inputs and outputs, as well as internal noise sources and operating parameters. These sub-models are then configured using data-flow diagrams to operate together to reflect the performance of the entire DIAL system. This modeling philosophy allows the developer to have a realistic indication of the nature of signals throughout the system and to design components and processing in a realistic environment. Current component models include atmospheric absorption and scattering losses, plume absorption and scattering losses, background, telescope and optical filter models, PMT (photomultiplier tube) with realistic noise sources, amplifier operation and noise, A/D converter operation, noise and distortion, pulse averaging, and DIAL computation. Preliminary results of the model will be presented indicating the expected model operation depicting the October field test at the NTS spill test facility. Indications will be given concerning near-term upgrades to the model.

  1. Simultaneous whole body 18F-fluorodeoxyglucose positron emission tomography magnetic resonance imaging for evaluation of pediatric cancer: Preliminary experience and comparison with 18F-fluorodeoxyglucose positron emission tomography computed tomography

    PubMed Central

    Pugmire, Brian S; Guimaraes, Alexander R; Lim, Ruth; Friedmann, Alison M; Huang, Mary; Ebb, David; Weinstein, Howard; Catalano, Onofrio A; Mahmood, Umar; Catana, Ciprian; Gee, Michael S

    2016-01-01

    AIM: To describe our preliminary experience with simultaneous whole body 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography and magnetic resonance imaging (PET-MRI) in the evaluation of pediatric oncology patients. METHODS: This prospective, observational, single-center study was Health Insurance Portability and Accountability Act-compliant, and institutional review board approved. To be eligible, a patient was required to: (1) have a known or suspected cancer diagnosis; (2) be under the care of a pediatric hematologist/oncologist; and (3) be scheduled for clinically indicated 18F-FDG positron emission tomography-computed tomography (PET-CT) examination at our institution. Patients underwent PET-CT followed by PET-MRI on the same day. PET-CT examinations were performed using standard department protocols. PET-MRI studies were acquired with an integrated 3 Tesla PET-MRI scanner using whole body T1 Dixon, T2 HASTE, EPI diffusion-weighted imaging (DWI) and STIR sequences. No additional radiotracer was given for the PET-MRI examination. Both PET-CT and PET-MRI examinations were reviewed by consensus by two study personnel. Test performance characteristics of PET-MRI, for the detection of malignant lesions, including FDG maximum standardized uptake value (SUVmax) and minimum apparent diffusion coefficient (ADCmin), were calculated on a per lesion basis using PET-CT as a reference standard. RESULTS: A total of 10 whole body PET-MRI exams were performed in 7 pediatric oncology patients. The mean patient age was 16.1 years (range 12-19 years) including 6 males and 1 female. A total of 20 malignant and 21 benign lesions were identified on PET-CT. PET-MRI SUVmax had excellent correlation with PET-CT SUVmax for both benign and malignant lesions (R = 0.93). PET-MRI SUVmax > 2.5 had 100% accuracy for discriminating benign from malignant lesions using PET-CT reference. Whole body DWI was also evaluated: the mean ADCmin of malignant lesions (780.2 + 326.6) was

  2. Absorbed Radiation Dose in Radiosensitive Organs Using 64- and 320-Row Multidetector Computed Tomography: A Comparative Study

    PubMed Central

    Khan, Atif N.; Nikolic, Boris; Khan, Mohammad K.; Kang, Jian; Khosa, Faisal

    2014-01-01

    Aim. To determine absorbed radiation dose (ARD) in radiosensitive organs during prospective and full phase dose modulation using ECG-gated MDCTA scanner under 64- and 320-row detector modes. Methods. Female phantom was used to measure organ radiation dose. Five DP-3 radiation detectors were used to measure ARD to lungs, breast, and thyroid using the Aquilion ONE scanner in 64- and 320-row modes using both prospective and dose modulation in full phase acquisition. Five measurements were made using three tube voltages: 100, 120, and 135 kVp at 400 mA at heart rate (HR) of 60 and 75 bpm for each protocol. Mean acquisition was recorded in milligrays (mGy). Results. Mean ARD was less for 320-row versus 64-row mode for each imaging protocol. Prospective EKG-gated imaging protocol resulted in a statistically lower ARD using 320-row versus 64-row modes for midbreast (6.728 versus 19.687 mGy, P < 0.001), lung (6.102 versus 21.841 mGy, P < 0.001), and thyroid gland (0.208 versus 0.913 mGy; P < 0.001). Retrospective imaging using 320- versus 64-row modes showed lower ARD for midbreast (10.839 versus 43.169 mGy, P < 0.001), lung (8.848 versus 47.877 mGy, P < 0.001), and thyroid gland (0.057 versus 2.091 mGy; P < 0.001). ARD reduction was observed at lower kVp and heart rate. Conclusions. Dose reduction to radiosensitive organs is achieved using 320-row compared to 64-row modes for both prospective and retrospective gating, whereas 64-row mode is equivalent to the same model 64-row MDCT scanner. PMID:25170427

  3. Preliminary Drill Sites

    DOE Data Explorer

    Lane, Michael

    2013-06-28

    Preliminary locations for intermediate depth temperature gradient holes and/or resource confirmation wells based on compilation of geological, geophysical and geochemical data prior to carrying out the DOE-funded reflection seismic survey.

  4. Preliminary Response Analysis of AUV

    NASA Astrophysics Data System (ADS)

    Hariri, Azian; Basharie, Siti Mariam; Ghani, Mohamad Hanifah Abd.

    2010-06-01

    Development of Autonomous Unmanned Vehicle (AUV) involves a great task to fully understand the overall working principles of an UAV that needed time, experience and a wide range of intelligence to cover the entire scientific facts. This study is done by means to acquire the fundamental knowledge in understanding the stability and response of an UAV. The longitudinal response and stability of UAV owing to deflection of stern plane during trimmed equilibrium motion can be computed by solving the AUV equation of motion. In this study, the AUV equations of motion were rederived and the solution was computed with the aid of Matlab software. From the existing AUV, a new dimension, weight and speed were specified to be used in the rederivation of the linearised AUV longitudinal equations of motion. From the analysis done, the longitudinal response AUV shows the stern plane and thrust has relatively steady longitudinal control power and quick response characteristic. The results had successfully given a preliminary insight of the specified AUV response and dynamic stability.

  5. Catehol-O-Methyltransferase gene Val158Met polymorphism as a potential predictor of response to computer-assisted delivery of cognitive-behavioral therapy among cocaine-dependent individuals: Preliminary findings from a randomized controlled trial

    PubMed Central

    Carroll, Kathleen M.; Herman, Aryeh; DeVito, Elise E.; Frankforter, Tami L.; Potenza, Marc N; Sofuoglu, Mehmet

    2015-01-01

    Background Findings from uncontrolled studies suggest that the COMT Val108/158Met polymorphism may affect response to cognitive behavioral therapy (CBT) in some populations. Using data from a randomized controlled trial evaluating computerized CBT (CBT4CBT), we evaluated treatment response by COMT genotype, with the a priori hypothesis that Val carriers would have improved response to computerized delivery of CBT. Methods 101 cocaine-dependent individuals, of whom 81 contributed analyzable genetic samples, were randomized to standard methadone maintenance treatment plus CBT4CBT or standard treatment alone in an 8-week trial. Results There was a significant genotype by time effect on frequency of cocaine use from baseline to the end of the 6-month follow-up, suggesting greater reductions over time for Val carriers relative to individuals with the Met/Met genotype. There was a significant treatment condition by genotype interactions for rates of participants attaining 21 or more days of continuous abstinence as well as self-reported percent days of abstinence, suggesting less cocaine use among Val carriers when assigned to CBT compared to standard treatment. Exploration of possible mechanisms using measures of attentional biased also pointed to greater change over time in these measures among the Val carriers assigned to CBT. Conclusion These are the first data from a randomized controlled trial indicating significant interactions of COMT polymorphism and behavioral therapy condition on treatment outcome, where Val carriers appeared to respond particularly well to computerized CBT. These preliminary data point to a potential biomarker of response to CBT linked to its putative mechanism of action, enhanced cognitive control. PMID:25930952

  6. Computers and Computer Resources.

    ERIC Educational Resources Information Center

    Bitter, Gary

    1980-01-01

    This resource directory provides brief evaluative descriptions of six popular home computers and lists selected sources of educational software, computer books, and magazines. For a related article on microcomputers in the schools, see p53-58 of this journal issue. (SJL)

  7. Genesis Preliminary Examination Plans

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.; Stansbery, E. K.

    2004-01-01

    The purpose of preliminary examination of the Genesis sample collectors is to provide information on the condition and availability of collector materials to the science community as a basis for allocation requests. Similarly, the information will be used by the Genesis Sample Allocation sub-committee of CAPTEM to determine the optimum allocation scheme, and by the Genesis Curator to determine the processing sequence for allocation production. The plan includes a decision process and detailed examination and documentation protocol for whole arrays and individual collectors (wafers, concentrator targets, bulk metallic glass, gold foil, and polished aluminum). It also includes a plan for communicating the information obtained to the scientific community. The plan does not include a detailed plan for preliminary examination of the SRC lid foil collectors, the process for removal of individual collectors from their frames, or for the subsequent subdivision of collector materials for allocation.

  8. On Preliminary Breakdown

    NASA Astrophysics Data System (ADS)

    Beasley, W. H.; Petersen, D.

    2013-12-01

    The preliminary breakdown phase of a negative cloud-to-ground lightning flash was observed in detail. Observations were made with a Photron SA1.1 high-speed video camera operating at 9,000 frames per second, fast optical sensors, a flat-plate electric field antenna covering the SLF to MF band, and VHF and UHF radio receivers with bandwidths of 20 MHz. Bright stepwise extensions of a negative leader were observed at an altitude of 8 km during the first few milliseconds of the flash, and were coincident with bipolar electric field pulses called 'characteristic pulses'. The 2-D step lengths of the preliminary processes were in excess of 100 meters, with some 2-D step lengths in excess of 200 meters. Smaller and shorter unipolar electric field pulses were superposed onto the bipolar electric field pulses, and were coincident with VHF and UHF radio pulses. After a few milliseconds, the emerging negative stepped leader system showed a marked decrease in luminosity, step length, and propagation velocity. Details of these events will be discussed, including the possibility that the preliminary breakdown phase consists not of a single developing lightning leader system, but of multiple smaller lightning leader systems that eventually join together into a single system.

  9. Computer-Based Education at Cedarville College: A White Paper.

    ERIC Educational Resources Information Center

    Rogers, Rex M.

    In order to provide a framework for addressing computer literacy and program development considerations, this document discusses issues in computer implementation on higher education campuses and outlines a preliminary plan for Cedarville College to meet computer-related needs of faculty and students. The growth of the computer industry and the…

  10. Automated CPX support system preliminary design phase

    NASA Technical Reports Server (NTRS)

    Bordeaux, T. A.; Carson, E. T.; Hepburn, C. D.; Shinnick, F. M.

    1984-01-01

    The development of the Distributed Command and Control System (DCCS) is discussed. The development of an automated C2 system stimulated the development of an automated command post exercise (CPX) support system to provide a more realistic stimulus to DCCS than could be achieved with the existing manual system. An automated CPX system to support corps-level exercise was designed. The effort comprised four tasks: (1) collecting and documenting user requirements; (2) developing a preliminary system design; (3) defining a program plan; and (4) evaluating the suitability of the TRASANA FOURCE computer model.

  11. Modeling the complete Otto cycle - Preliminary version

    NASA Technical Reports Server (NTRS)

    Zeleznik, F. J.; Mcbride, B. J.

    1977-01-01

    A description is given of the equations and the computer program being developed to model the complete Otto cycle. The program incorporates such important features as: (1) heat transfer, (2) finite combustion rates, (3) complete chemical kinetics in the burned gas, (4) exhaust gas recirculation, and (5) manifold vacuum or supercharging. Changes in thermodynamic, kinetic and transport data as well as model parameters can be made without reprogramming. Preliminary calculations indicate that: (1) chemistry and heat transfer significantly affect composition and performance, (2) there seems to be a strong interaction among model parameters, and (3) a number of cycles must be calculated in order to obtain steady-state conditions.

  12. Preliminary System Design of the SWRL Financial System.

    ERIC Educational Resources Information Center

    Ikeda, Masumi

    The preliminary system design of the computer-based Southwest Regional Laboratory's (SWRL) Financial System is outlined. The system is designed to produce various management and accounting reports needed to maintain control of SWRL operational and financial activities. Included in the document are descriptions of the various types of system…

  13. The ASTRO-1 preliminary design review coupled load analysis

    NASA Technical Reports Server (NTRS)

    Mcghee, D. S.

    1984-01-01

    Results of the ASTRO-1 preliminary design review coupled loads analysis are presented. The M6.0Y Generic Shuttle mathematical models were used. Internal accelerations, interface forces, relative displacements, and net e.g., accelerations were recovered for two ASTRO-1 payloads in a tandem configuration. Twenty-seven load cases were computed and summarized. Load exceedences were found and recommendations made.

  14. Environmental Survey preliminary report

    SciTech Connect

    Not Available

    1988-04-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Sandia National Laboratories conducted August 17 through September 4, 1987. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Sandia National Laboratories-Albuquerque (SNLA). The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at SNLA, and interviews with site personnel. 85 refs., 49 figs., 48 tabs.

  15. Assessment of Lipiodol Deposition and Residual Cancer for Hepatocellular Carcinoma After Transcatheter Arterial Chemoembolization via Iodine-Based Material Decomposition Images with Spectral Computed Tomography Imaging: A Preliminary Study

    PubMed Central

    Xu, Yanhong; Xiao, An; Yang, Jia; Zhang, Zaixian; Zhang, Guixiang

    2015-01-01

    Background: It is critical to follow up hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) in clinical practice. Computed tomography (CT) is used to assess lipiodol deposition, whereas it is difficult to assess hypovascular residual cancer masked by lipiodol. In contrast, magnetic resonance imaging (MRI) is superior to CT in showing residual cancer, but cannot display lipiodol deposition. Objectives: The aim of this study was to investigate the value of spectral CT imaging in both lipiodol deposition and residual cancer for HCC patients after TACE. Patients and Methods: Ten HCC patients after treated with TACE underwent Discovery CT750 HD and MRI750 3T examination. Receiver operating characteristic (ROC) curves of iodine-based material decomposition images, monochromatic images and conventional CT images were generated. Results: Consequently, 30 residual lesions were detected in MRI of 10 patients. They were found in iodine-based images and monochromatic images versus 29 in conventional CT images. The area under ROC curves for the lesion-to-normal parenchyma ratio (LNR) on arterial phase (AP) in iodine-based material decomposition images, monochromatic images and conventional CT images were 0.933, 0.833 and 0.817, respectively. Conclusion: The study data highlighted good value of iodine-based material decomposition images of spectral CT in assessment of both lipiodol deposition and residual cancer for follow-up of HCC patients previously treated with TACE. PMID:26715981

  16. Preliminary Results from the Application of Automated Adjoint Code Generation to CFL3D

    NASA Technical Reports Server (NTRS)

    Carle, Alan; Fagan, Mike; Green, Lawrence L.

    1998-01-01

    This report describes preliminary results obtained using an automated adjoint code generator for Fortran to augment a widely-used computational fluid dynamics flow solver to compute derivatives. These preliminary results with this augmented code suggest that, even in its infancy, the automated adjoint code generator can accurately and efficiently deliver derivatives for use in transonic Euler-based aerodynamic shape optimization problems with hundreds to thousands of independent design variables.

  17. Preliminary ISIS users manual

    NASA Technical Reports Server (NTRS)

    Grantham, C.

    1979-01-01

    The Interactive Software Invocation (ISIS), an interactive data management system, was developed to act as a buffer between the user and host computer system. The user is provided by ISIS with a powerful system for developing software or systems in the interactive environment. The user is protected from the idiosyncracies of the host computer system by providing such a complete range of capabilities that the user should have no need for direct access to the host computer. These capabilities are divided into four areas: desk top calculator, data editor, file manager, and tool invoker.

  18. Cost and Effectiveness of Computer Based Training.

    ERIC Educational Resources Information Center

    Fletcher, J. D.

    The methodology and results of cost-effectiveness evaluations of computer based instruction used in military training are discussed. Methodological issues center on decisions about what cost elements and what effectiveness measures should be included, and how they should be combined. Preliminary results suggest that, in general, computer based…

  19. Topics in computational physics

    NASA Astrophysics Data System (ADS)

    Monville, Maura Edelweiss

    Computational Physics spans a broad range of applied fields extending beyond the border of traditional physics tracks. Demonstrated flexibility and capability to switch to a new project, and pick up the basics of the new field quickly, are among the essential requirements for a computational physicist. In line with the above mentioned prerequisites, my thesis described the development and results of two computational projects belonging to two different applied science areas. The first project is a Materials Science application. It is a prescription for an innovative nano-fabrication technique that is built out of two other known techniques. The preliminary results of the simulation of this novel nano-patterning fabrication method show an average improvement, roughly equal to 18%, with respect to the single techniques it draws on. The second project is a Homeland Security application aimed at preventing smuggling of nuclear material at ports of entry. It is concerned with a simulation of an active material interrogation system based on the analysis of induced photo-nuclear reactions. This project consists of a preliminary evaluation of the photo-fission implementation in the more robust radiation transport Monte Carlo codes, followed by the customization and extension of MCNPX, a Monte Carlo code developed in Los Alamos National Laboratory, and MCNP-PoliMi. The final stage of the project consists of testing the interrogation system against some real world scenarios, for the purpose of determining the system's reliability, material discrimination power, and limitations.

  20. Computer Music

    NASA Astrophysics Data System (ADS)

    Cook, Perry R.

    This chapter covers algorithms, technologies, computer languages, and systems for computer music. Computer music involves the application of computers and other digital/electronic technologies to music composition, performance, theory, history, and the study of perception. The field combines digital signal processing, computational algorithms, computer languages, hardware and software systems, acoustics, psychoacoustics (low-level perception of sounds from the raw acoustic signal), and music cognition (higher-level perception of musical style, form, emotion, etc.).

  1. Computer Music

    NASA Astrophysics Data System (ADS)

    Cook, Perry

    This chapter covers algorithms, technologies, computer languages, and systems for computer music. Computer music involves the application of computers and other digital/electronic technologies to music composition, performance, theory, history, and perception. The field combines digital signal processing, computational algorithms, computer languages, hardware and software systems, acoustics, psychoacoustics (low-level perception of sounds from the raw acoustic signal), and music cognition (higher-level perception of musical style, form, emotion, etc.). Although most people would think that analog synthesizers and electronic music substantially predate the use of computers in music, many experiments and complete computer music systems were being constructed and used as early as the 1950s.

  2. Time-lapse electrical resistivity tomography: a powerful tool for landslide monitoring?

    NASA Astrophysics Data System (ADS)

    Perrone, A.

    2011-12-01

    The extreme rainfall events and the quick snowmelt occurrences play an important role in the triggering of the landslides. The occurrence of one of these factors can determine the variation of water content in the first layers of the subsoil and as a consequence a quick soil saturation inducing both an increase in pore-water pressures and the overloaded of the slopes progressively collapsing. The electrical resistivity, self-potential, electromagnetic induction and GPR methods can be considered as the most appropriate for assessing the presence of water in the underground. Such methods allow us to study the behavior of water content over much wider and deeper areas than those offered by traditional methods (thermo-gravimetric, tensiometric, TDR, etc) based on spot measures and concerning small volumes. In particular, the Electrical Resistivity Tomography (ERT), which has already proved to be a powerful tool both for the geometrical reconstruction of a landslide body (location of sliding surface, estimation of the thickness of the slide material) and the individuation of high water content areas, can be considered as an alternative tool to be employed for a qualitative and quantitative water content monitoring in the first layers of the subsoil. Indeed, time-lapse 2D ERT can be tested in order to gather information on the temporal and spatial patterns of water infiltration processes and water content variation. This work reports the preliminary results from a new prototype system planned to obtain time-lapse 2D ERTs, TDR and precipitation measurements in two landslide areas located in the Southern Apennine chain (Italy). The system was planned with the aim to estimate the variation of the resistivity parameter on a long period considering the water content variation, the rain water infiltration and the seasonal changes. The prototype system, linked to a pc used for storing data and managing the time interval acquisition, consists of: a resistivimeter connected to a

  3. Preliminary Analysis of Photoreading

    NASA Technical Reports Server (NTRS)

    McNamara, Danielle S.

    2000-01-01

    The purpose of this project was to provide a preliminary analysis of a reading strategy called PhotoReading. PhotoReading is a technique developed by Paul Scheele that claims to increase reading rate to 25,000 words per minute (Scheele, 1993). PhotoReading itself involves entering a "relaxed state" and looking at, but not reading, each page of a text for a brief moment (about I to 2 seconds). While this technique has received attention in the popular press, there had been no objective examinations of the technique's validity. To examine the effectiveness of PhotoReading, the principal investigator (i.e., trainee) participated in a PhotoReading workshop to learn the technique. Parallel versions of two standardized and three experimenter-created reading comprehension tests were administered to the trainee and an expert user of the PhotoReading technique to compare the use of normal reading strategies and the PhotoReading technique by both readers. The results for all measures yielded no benefits of using the PhotoReading technique. The extremely rapid reading rates claimed by PhotoReaders were not observed; indeed, the reading rates were generally comparable to those for normal reading. Moreover, the PhotoReading expert generally showed an increase in reading time when using the PhotoReading technique in comparison to when using normal reading strategies to process text. This increase in reading time when PhotoReading was accompanied by a decrease in text comprehension.

  4. Enhanced preliminary assessment

    SciTech Connect

    Not Available

    1992-02-01

    An Enhanced Preliminary Assessment was conducted at Fort Benjamin Harrison (FBH) Indiana, which is located approximately 12 miles from downtown Indianapolis in Lawrence Township, Marion County. FBH contains 2,501 acres, of which approximately 1,069 acres is covered by woodlands. Activities at FBH include administration, training, housing, and support. Sensitive environments at FBH include wetlands, habitat areas for the endangered Indiana bat, endangered plants, and historically and archeologically significant areas. FBH is a U.S. Army Soldier Support Center under the jurisdiction of the U.S. Army Training and Doctrine Command (TRADOC). Based on information obtained during and subsequent to a site visit (15 through 18 October 1991), 36 types of Areas Requiring Environmental Evaluation (AREEs) were identified and grouped by the following categories: Facility Operations; Maintenance/Fueling Operations; Water Treatment Operations; Training Areas; Hazardous Materials Storage/Waste Handling Areas; Sanitary Wastewater Treatment Plants; Storage Tanks; Landfills/Incinerators; Medical Facilities; Burn Pit Areas; Spill Areas; Ammunition Storage; Coal Storage; and Facility-wide AREEs. This report presents a summary of findings for each AREE and recommendations for further action.

  5. Computer Applications Planning. A Guide to Planning and Implementing a District-Wide Computer Program.

    ERIC Educational Resources Information Center

    Mojkowski, Charles

    Designed to help school districts move from exploring the use of computers in the classroom to the comprehensive planning and development of computer education programs, this guide is organized around five steps essential to the process of developing a district program. Phase 1 includes the following preliminary activities involved in planning for…

  6. Optical computer motherboards

    NASA Astrophysics Data System (ADS)

    Jannson, Tomasz P.; Xu, Guoda; Bartha, John M.; Gruntman, Michael A.

    1997-09-01

    In this paper, we investigate the application of precision plastic optics into a communication/computer sub-system, such as a hybrid computer motherboard. We believe that using optical waveguides for next-generation computer motherboards can provide a high performance alternative for present multi-layer printed circuit motherboards. In response to this demand, we suggest our novel concept of a hybrid motherboard based on an internal-fiber-coupling (IFC) wavelength-division-multiplexing (WDM) optical backplane. The IFC/WDM backplane provides dedicated Tx/Rx connections, and applies low-cost, high-performance components, including CD LDs, GRIN plastic fibers, molding housing, and nonimaging optics connectors. Preliminary motherboard parameters are: speed 100 MHz/100 m, or 1 GHz/10 m; fiber loss approximately 0.01 dB/m; almost zero fan-out/fan-in optical power loss, and eight standard wavelength channels. The proposed hybrid computer motherboard, based on innovative optical backplane technology, should solve low-speed, low-parallelism bottlenecks in present electric computer motherboards.

  7. Pygmalion's Computer.

    ERIC Educational Resources Information Center

    Peelle, Howard A.

    Computers have undoubtedly entered the educational arena, mainly in the areas of computer-assisted instruction (CAI) and artificial intelligence, but whether educators should embrace computers and exactly how they should use them are matters of great debate. The use of computers in support of educational administration is widely accepted.…

  8. Preliminary development of an intelligent computer assistant for engine monitoring

    NASA Technical Reports Server (NTRS)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1989-01-01

    As part of the F-18 high-angle-of-attack vehicle program, an AI method was developed for the real time monitoring of the propulsion system and for the identification of recovery procedures for the F404 engine. The aim of the development program is to provide enhanced flight safety and to reduce the duties of the propulsion engineers. As telemetry data is received, the results are continually displayed in a number of different color graphical formats. The system makes possible the monitoring of the engine state and the individual parameters. Anomaly information is immediately displayed to the engineer.

  9. Synthesis, preliminary bioevaluation and computational analysis of caffeic acid analogues.

    PubMed

    Liu, Zhiqian; Fu, Jianjun; Shan, Lei; Sun, Qingyan; Zhang, Weidong

    2014-01-01

    A series of caffeic acid amides were designed, synthesized and evaluated for anti-inflammatory activity. Most of them exhibited promising anti-inflammatory activity against nitric oxide (NO) generation in murine macrophage RAW264.7 cells. A 3D pharmacophore model was created based on the biological results for further structural optimization. Moreover, predication of the potential targets was also carried out by the PharmMapper server. These amide analogues represent a promising class of anti-inflammatory scaffold for further exploration and target identification. PMID:24857914

  10. Synthesis, Preliminary Bioevaluation and Computational Analysis of Caffeic Acid Analogues

    PubMed Central

    Liu, Zhiqian; Fu, Jianjun; Shan, Lei; Sun, Qingyan; Zhang, Weidong

    2014-01-01

    A series of caffeic acid amides were designed, synthesized and evaluated for anti-inflammatory activity. Most of them exhibited promising anti-inflammatory activity against nitric oxide (NO) generation in murine macrophage RAW264.7 cells. A 3D pharmacophore model was created based on the biological results for further structural optimization. Moreover, predication of the potential targets was also carried out by the PharmMapper server. These amide analogues represent a promising class of anti-inflammatory scaffold for further exploration and target identification. PMID:24857914

  11. Preliminary orbital parallax catalog

    NASA Technical Reports Server (NTRS)

    Halliwell, M.

    1981-01-01

    The study is undertaken to calibrate the more reliable parallaxes derived from a comparison of visual and spectroscopic orbits and to encourage observational studies of other promising binaries. The methodological techniques used in computing orbital parallaxes are analyzed. Tables summarizing orbital data and derived system properties are then given. Also given is a series of detailed discussions of the 71 individual systems included in the tables. Data are listed for 57 other systems which are considered promising candidates for eventual orbital parallax determination.

  12. We Teach the Children: Computer Literacy as a Feminist Issue.

    ERIC Educational Resources Information Center

    Rampy, Leah Moran

    Preliminary research on the distribution and use of computers in public schools indicates the existance of socioeconomic, regional, and sex inequalities. Inequity is found in the ownership of computers by non-Southern schools and by schools serving students from middle and high socioeconomic levels. Within schools owning computers, inequity is…

  13. Computed tomography of electronics

    NASA Astrophysics Data System (ADS)

    Bossi, Richard H.; Kruse, Robert J.; Knutson, Benjamin W.

    1989-12-01

    The application of Computed Tomography (CT) and laminography was tested on a variety of electronic components. The effort was performed as a preliminary testing task assignment in the Advanced Development of X ray Computed Tomography Application program. A key area for testing was printed circuit boards for the inspection of solder bonds and in particular for leadless chip carrier devices. During the course of the task assignment several other categories of electronic devices were examined including transformers, connectors, switches from solution and contrast sensitivity phantoms developed for the programs were used to establish quantitative measures of capability used to generate images. This preliminary testing of electronics lead to the conclusion that higher resolution CT scanning is needed to resolve details of interest. CT testing on commercially available system could resolve high contrast details in the range of 2 to 4 lp/mm; however, in many electronic components finer resolution is needed to detect microcracking, voiding and other features. Further testing on high resolution system is recommended. Two areas of immediate potential economic payback for electronics inspection were identified; the inspection of high volume printed circuit board production using high speed laminography and nondestructive failure analysis studies components using high-resolution CT.

  14. In Situ Cryo-Electron Tomography: A Post-Reductionist Approach to Structural Biology.

    PubMed

    Asano, Shoh; Engel, Benjamin D; Baumeister, Wolfgang

    2016-01-29

    Cryo-electron tomography is a powerful technique that can faithfully image the native cellular environment at nanometer resolution. Unlike many other imaging approaches, cryo-electron tomography provides a label-free method of detecting biological structures, relying on the intrinsic contrast of frozen cellular material for direct identification of macromolecules. Recent advances in sample preparation, detector technology, and phase plate imaging have enabled the structural characterization of protein complexes within intact cells. Here, we review these technical developments and outline a detailed computational workflow for in situ structural analysis. Two recent studies are described to illustrate how this workflow can be adapted to examine both known and unknown cellular complexes. The stage is now set to realize the promise of visual proteomics-a complete structural description of the cell's native molecular landscape. PMID:26456135

  15. Preliminary design report for the prototypical fuel rod consolidation system

    SciTech Connect

    Rosa, J.M.

    1986-12-03

    This report documents NUTECH's preliminary design of a dry, spent fuel rod consolidation system. This preliminary design is the result of Phase I of a planned four phase project. The present report on this project provides a considerable amount of detail for a preliminary design effort. The design and all of its details are described in this Preliminary Design Report (PDR). The NUTECH dry rod consolidation system described herein is remotely operated. It provides for automatic operation, but with operator hold points between key steps in the process. The operator has the ability to switch to a manual operation mode at any point in the process. The system is directed by the operator using an executive computer which controls and coordinates the operation of the in-cell equipment. The operator monitors the process using an in-cell closed circuit television (CCTV) system with audio output and equipment status displays on the computer monitor. The in-cell mechanical equipment consists of the following: (1) two overhead cranes with manipulators; (2) a multi-degree of freedom fuel handling table and its clamping equipment; (3) a fuel assembly end fitting removal station and its tools; (4) a consolidator (which pulls rods, assembles the consolidated bundle and loads the canister); (5) a canister end cap welder and weld inspection system; (6) decontamination systems; and (7) the CCTV and microphone systems.

  16. Positron emission tomography: a technology assessment of PET imaging--past, present, and future.

    PubMed

    Frazee, David

    2004-01-01

    Emerging from its origins in the basements of research laboratories, positron emission tomography (PET), has established itself as a premier clinical imaging modality. It just took 50 years to get there. PET and the ever-popular, dual imaging modality combination of positron emission tomography/computed tomography (PET/CT) have taken hold of the spotlight at the national meetings of the Radiological Society of North America (RSNA) and the Society of Nuclear Medicine (SNM)--and they are not about to give it up. Many major imaging manufacturers--those companies that make up the majority of imaging sales in the US--now offer some type of PET and or PET/CT scanner. The technology of PET imaging continues to improve in image resolution, speed, and acceptance by its skeptical, but continually growing, referral base. With the increasing number of regional cyclotron facilities throughout the US each year, the abundance of mobile PET companies competing for business, and, most important, the number of clinical procedures that now qualify for reimbursement, more facilities now have the ability to implement PETimaging. This article discusses the progress of PET, from its beginnings 50 years ago, to where it is today--and the direction it is headed in the future. PMID:15633509

  17. Tomography: A window on the role of sulfur in the structure of micrometeorites

    NASA Astrophysics Data System (ADS)

    Taylor, Susan; Jones, Keith W.; Herzog, Gregory F.; Hornig, Claire E.

    2011-10-01

    To determine the role played by sulfides in the formation of vesicles and FeNi metal beads, we mapped the locations and tabulated the numbers of sulfides, metal beads, and vesicles in 1583 sectioned micrometeorites (MMs) using conventional microscopy and in 190 whole MMs using synchrotron computed microtomography (SCMT). Both the section and the SCMT images show that sulfides melt, coalesce, and migrate to the MMs surface. The decomposition of sulfides may occur during all these stages. Given the sulfide morphologies and compositions that we see in section, we think the breakdown of Ni sulfides produces the FeNi beads. The SCMT images show that metal beads are common in melted MMs, >50% have them. Vesicles in porphyritic and scoriaceous MMs are also probably formed as sulfides decompose. Not only do sulfides abut the vesicles but also the temperatures at which sulfides decompose overlap those at which MM surfaces first melt and temporarily seal, suggesting that S gases could produce most of these vesicles. As the vesicle shapes and patterns of distribution differ among MM classes, tomography can be used to nondestructively screen for specific types of MMs. Tomography is a powerful tool for visualizing the three-dimensional distribution of metal beads, sulfides, mean densities, and vesicles in MMs.

  18. Reproducibility of Tear Meniscus Measurement by Fourier-Domain Optical Coherence Tomography: A Pilot Study

    PubMed Central

    Zhou, Sheng; Li, Yan; Lu, Ake Tzu-Hui; Liu, Pengfei; Tang, Maolong; Yiu, Samuel C.; Huang, David

    2009-01-01

    BACKGROUND AND OBJECTIVE To study the reproducibility of tear meniscus measurement with high-speed high-resolution Fourier-domain optical coherence tomography (FD-OCT). PATIENTS AND METHODS Twenty normal participants were enrolled in this prospective study. The lower tear meniscus in the right eye of each subject was imaged by vertical scans centered on the inferior cornea and the lower eyelid using an FD-OCT system (RTVue; Optovue, Inc., Fremont, CA) with a corneal adaptor. The system performs 26,000 axial scans per second and has a 5-micron axial resolution. Each subject was examined at two visits 30 to 60 days apart. Each eye was scanned twice on each visit. The scans were taken 2 seconds after a blink. The lower meniscus height, depth, and cornea-meniscus angle were measured with a computer caliper. The cross-sectional area was calculated using a two-triangle approximation. RESULTS The between-visits coefficient of variation was 17.5%, 18.0%, 35.5%, and 12.2% for meniscus height, depth, area, and angle, respectively. The intraclass correlations for these parameters were 0.605, 0.558, 0.567, and 0.367, respectively. CONCLUSION FD-OCT measures lower tear meniscus dimensions and area with higher between-visits reproducibility than previous OCT instruments. FD-OCT may be a useful way to measure dry eye severity and treatment effectiveness. PMID:19772266

  19. Multimode electromagnetic target discriminator: preliminary data results

    NASA Astrophysics Data System (ADS)

    Black, Christopher J.; McMichael, Ian T.; Nelson, Carl V.

    2004-09-01

    This paper describes the Multi-mode Electromagnetic Target Discriminator (METD) sensor and presents preliminary results from recent field experiments. The METD sensor was developed for the US Army RDECOM NVESD by The Johns Hopkins University Applied Physics Laboratory. The METD, based on the technology of the previously developed Electromagnetic Target Discriminator (ETD), is a spatial scanning electromagnetic induction (EMI) sensor that uses both the time-domain (TD) and the frequency-domain (FD) for target detection and classification. Data is collected with a custom data acquisition system and wirelessly transmitted to a base computer. We show that the METD has a high signal-to-noise ratio (SNR), the ability to detect voids created by plastic anti-tank (AT) mines, and is practical for near real-time data processing.

  20. Bacterial Identification Using Light Scattering Measurements: a Preliminary Report

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.

    1971-01-01

    The light scattering properties of single bacterial cells were examined as a possible means of identification. Three species were studied with streptococcus faecalis exhibiting a unique pattern; the light-scattering traces for staphylococcus aureus and escherichia coli were quite similar although differences existed. Based on preliminary investigations, the light scattering approach appeared promising with additional research needed to include a wide variety of bacterial species, computer capability to handle and analyze data, and expansion of light scattering theory to include bacterial cells.

  1. Preliminary result of Indonesian strain map based on geodetic measurements

    NASA Astrophysics Data System (ADS)

    Susilo, Meilano, Irwan; Abidin, Hasanuddin Z.; Sapiie, Benyamin; Efendi, Joni; Wijanarto, Antonius B.

    2016-05-01

    GPS measurements from 1993 until 2014 across Indonesia region are providing longer time series at 2 - 3 millimetre-level precision from which surface velocity estimates are derived. In this study, we use this GPS velocities field to construct a crustal strain rate map and not including the physical model yet. In our preliminary result, we only compute the magnitude of the strain rate. The strain map is useful to construct the deformation model in Indonesia and to support the Indonesia datum.

  2. Computational dosimetry

    SciTech Connect

    Siebert, B.R.L.; Thomas, R.H.

    1996-01-01

    The paper presents a definition of the term ``Computational Dosimetry`` that is interpreted as the sub-discipline of computational physics which is devoted to radiation metrology. It is shown that computational dosimetry is more than a mere collection of computational methods. Computational simulations directed at basic understanding and modelling are important tools provided by computational dosimetry, while another very important application is the support that it can give to the design, optimization and analysis of experiments. However, the primary task of computational dosimetry is to reduce the variance in the determination of absorbed dose (and its related quantities), for example in the disciplines of radiological protection and radiation therapy. In this paper emphasis is given to the discussion of potential pitfalls in the applications of computational dosimetry and recommendations are given for their avoidance. The need for comparison of calculated and experimental data whenever possible is strongly stressed.

  3. COMPUTATIONAL TOXICOLOGY

    EPA Science Inventory

    Over the last several years, there has been increased pressure to utilize novel technologies derived from computational chemistry, molecular biology and systems biology in toxicological risk assessment. This new area has been referred to as "Computational Toxicology". Our resear...

  4. Cloud Computing

    SciTech Connect

    Pete Beckman and Ian Foster

    2009-12-04

    Chicago Matters: Beyond Burnham (WTTW). Chicago has become a world center of "cloud computing." Argonne experts Pete Beckman and Ian Foster explain what "cloud computing" is and how you probably already use it on a daily basis.

  5. Computer Recreations.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1989-01-01

    Reviews the performance of computer programs for writing poetry and prose, including MARK V. SHANEY, MELL, POETRY GENERATOR, THUNDER THOUGHT, and ORPHEUS. Discusses the writing principles of the programs. Provides additional information on computer magnification techniques. (YP)

  6. Computational Toxicology

    EPA Science Inventory

    Computational toxicology’ is a broad term that encompasses all manner of computer-facilitated informatics, data-mining, and modeling endeavors in relation to toxicology, including exposure modeling, physiologically based pharmacokinetic (PBPK) modeling, dose-response modeling, ...

  7. Spectral-element global waveform tomography: A second-generation upper-mantle model

    NASA Astrophysics Data System (ADS)

    French, S. W.; Lekic, V.; Romanowicz, B. A.

    2012-12-01

    The SEMum model of Lekic and Romanowicz (2011a) was the first global upper-mantle VS model obtained using whole-waveform inversion with spectral element (SEM: Komatitsch and Vilotte, 1998) forward modeling of time domain three component waveforms. SEMum exhibits stronger amplitudes of heterogeneity in the upper 200km of the mantle compared to previous global models - particularly with respect to low-velocity anomalies. To make SEM-based waveform inversion tractable at global scales, SEMum was developed using: (1) a version of SEM coupled to 1D mode computation in the earth's core (C-SEM, Capdeville et al., 2003); (2) asymptotic normal-mode sensitivity kernels, incorporating multiple forward scattering and finite-frequency effects in the great-circle plane (NACT: Li and Romanowicz, 1995); and (3) a smooth anisotropic crustal layer of uniform 60km thickness, designed to match global surface-wave dispersion while reducing the cost of time integration in the SEM. The use of asymptotic kernels reduced the number of SEM computations considerably (≥ 3x) relative to purely numerical approaches (e.g. Tarantola, 1984), while remaining sufficiently accurate at the periods of interest (down to 60s). However, while the choice of a 60km crustal-layer thickness is justifiable in the continents, it can complicate interpretation of shallow oceanic upper-mantle structure. We here present an update to the SEMum model, designed primarily to address these concerns. The resulting model, SEMum2, was derived using a crustal layer that again fits global surface-wave dispersion, but with a more geologically consistent laterally varying thickness: approximately honoring Crust2.0 (Bassin, et al., 2000) Moho depth in the continents, while saturating at 30km in the oceans. We demonstrate that this approach does not bias our upper mantle model, which is constrained not only by fundamental mode surface waves, but also by overtone waveforms. We have also improved our data-selection and

  8. Lesion quantification in oncological positron emission tomography: a maximum likelihood partial volume correction strategy.

    PubMed

    De Bernardi, Elisabetta; Faggiano, Elena; Zito, Felicia; Gerundini, Paolo; Baselli, Giuseppe

    2009-07-01

    A maximum likelihood (ML) partial volume effect correction (PVEC) strategy for the quantification of uptake and volume of oncological lesions in 18F-FDG positron emission tomography is proposed. The algorithm is based on the application of ML reconstruction on volumetric regional basis functions initially defined on a smooth standard clinical image and iteratively updated in terms of their activity and volume. The volume of interest (VOI) containing a previously detected region is segmented by a k-means algorithm in three regions: A central region surrounded by a partial volume region and a spill-out region. All volume outside the VOI (background with all other structures) is handled as a unique basis function and therefore "frozen" in the reconstruction process except for a gain coefficient. The coefficients of the regional basis functions are iteratively estimated with an attenuation-weighted ordered subset expectation maximization (AWOSEM) algorithm in which a 3D, anisotropic, space variant model of point spread function (PSF) is included for resolution recovery. The reconstruction-segmentation process is iterated until convergence; at each iteration, segmentation is performed on the reconstructed image blurred by the system PSF in order to update the partial volume and spill-out regions. The developed PVEC strategy was tested on sphere phantom studies with activity contrasts of 7.5 and 4 and compared to a conventional recovery coefficient method. Improved volume and activity estimates were obtained with low computational costs, thanks to blur recovery and to a better local approximation to ML convergence. PMID:19673203

  9. Computer Corner.

    ERIC Educational Resources Information Center

    Hampel, Paul J.

    1984-01-01

    Presents: (1) a computer program which will change a fraction into a decimal; (2) a program in which students supply missing lines to create the output given; and (3) suggestions for adding computer awareness to classrooms, including use of used punch cards and old computer-generated printouts. (JN)

  10. Computer Literacy.

    ERIC Educational Resources Information Center

    San Marcos Unified School District, CA.

    THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: After viewing many computer-literacy programs, we believe San Marcos Junior High School has developed a unique program which will truly develop computer literacy. Our hope is to give all students a comprehensive look at computers as they go through their two years here. They will not only learn the…

  11. Computer Literacy.

    ERIC Educational Resources Information Center

    Hunter, Beverly

    The concept of computer literacy is examined as it applies to two-year colleges. The paper begins with definitions of the term, emphasizing the skills, knowledge, and attitudes toward computers that are considered criteria for computer literacy. The paper continues by describing a conference at which educators attempted to visualize the technology…

  12. Computer Manual.

    ERIC Educational Resources Information Center

    Illinois State Office of Education, Springfield.

    This manual designed to provide the teacher with methods of understanding the computer and its potential in the classroom includes four units with exercises and an answer sheet. Unit 1 covers computer fundamentals, the mini computer, programming languages, an introduction to BASIC, and control instructions. Variable names and constants described…

  13. DNA computing.

    PubMed

    Gibbons, A; Amos, M; Hodgson, D

    1997-02-01

    DNA computation is a novel and exciting recent development at the interface of computer science and molecular biology. We describe the current activity in this field following the seminal work of Adleman, who recently showed how techniques of molecular biology may be applied to the solution of a computationally intractable problem. PMID:9013647

  14. Computer Starters!

    ERIC Educational Resources Information Center

    Instructor, 1983

    1983-01-01

    Instructor's Computer-Using Teachers Board members give practical tips on how to get a classroom ready for a new computer, introduce students to the machine, and help them learn about programing and computer literacy. Safety, scheduling, and supervision requirements are noted. (PP)

  15. Parallel Computing in SCALE

    SciTech Connect

    DeHart, Mark D; Williams, Mark L; Bowman, Stephen M

    2010-01-01

    The SCALE computational architecture has remained basically the same since its inception 30 years ago, although constituent modules and capabilities have changed significantly. This SCALE concept was intended to provide a framework whereby independent codes can be linked to provide a more comprehensive capability than possible with the individual programs - allowing flexibility to address a wide variety of applications. However, the current system was designed originally for mainframe computers with a single CPU and with significantly less memory than today's personal computers. It has been recognized that the present SCALE computation system could be restructured to take advantage of modern hardware and software capabilities, while retaining many of the modular features of the present system. Preliminary work is being done to define specifications and capabilities for a more advanced computational architecture. This paper describes the state of current SCALE development activities and plans for future development. With the release of SCALE 6.1 in 2010, a new phase of evolutionary development will be available to SCALE users within the TRITON and NEWT modules. The SCALE (Standardized Computer Analyses for Licensing Evaluation) code system developed by Oak Ridge National Laboratory (ORNL) provides a comprehensive and integrated package of codes and nuclear data for a wide range of applications in criticality safety, reactor physics, shielding, isotopic depletion and decay, and sensitivity/uncertainty (S/U) analysis. Over the last three years, since the release of version 5.1 in 2006, several important new codes have been introduced within SCALE, and significant advances applied to existing codes. Many of these new features became available with the release of SCALE 6.0 in early 2009. However, beginning with SCALE 6.1, a first generation of parallel computing is being introduced. In addition to near-term improvements, a plan for longer term SCALE enhancement

  16. Stardust Interstellar Preliminary Examination

    NASA Astrophysics Data System (ADS)

    Westphal, A.; Stardust Interstellar Preliminary Examation Team: http://www. ssl. berkeley. edu/~westphal/ISPE/

    2011-12-01

    A. J. Westphal, C. Allen, A. Ansari, S. Bajt, R. S. Bastien, H. A. Bechtel, J. Borg, F. E. Brenker, J. Bridges, D. E. Brownlee, M. Burchell, M. Burghammer, A. L. Butterworth, A. M. Davis, P. Cloetens, C. Floss, G. Flynn, D. Frank, Z. Gainsforth, E. Grün, P. R. Heck, J. K. Hillier, P. Hoppe, G. Huss, J. Huth, B. Hvide, A. Kearsley, A. J. King, B. Lai, J. Leitner, L. Lemelle, H. Leroux, R. Lettieri, W. Marchant, L. R. Nittler, R. Ogliore, F. Postberg, M. C. Price, S. A. Sandford, J.-A. Sans Tresseras, T. Schoonjans, S. Schmitz, G. Silversmit, A. Simionovici, V. A. Solé, R. Srama, T. Stephan, V. Sterken, J. Stodolna, R. M. Stroud, S. Sutton, M. Trieloff, P. Tsou, A. Tsuchiyama, T. Tyliszczak, B. Vekemans, L. Vincze, D. Zevin, M. E. Zolensky, >29,000 Stardust@home dusters ISPE author affiliations are at http://www.ssl.berkeley.edu/~westphal/ISPE/. In 2000 and 2002, a ~0.1m2 array of aerogel tiles and alumi-num foils onboard the Stardust spacecraft was exposed to the interstellar dust (ISD) stream for an integrated time of 200 days. The exposure took place in interplanetary space, beyond the orbit of Mars, and thus was free of the ubiquitous orbital debris in low-earth orbit that precludes effective searches for interstellar dust there. Despite the long exposure of the Stardust collector, <<100 ISD particles are expected to have been captured. The particles are thought to be ~1μm or less in size, and the total ISD collection is probably <10-6 by mass of the collection of cometary dust parti-cles captured in the Stardust cometary dust collector from the coma of the Jupiter-family comet Wild 2. Thus, although the first solid sample from the local interstellar medium is clearly of high interest, the diminutive size of the particles and the low numbers of particles present daunting challenges. Nevertheless, six recent developments have made a Preliminary Examination (PE) of this sample practical: (1) rapid automated digital optical scanning microscopy for three

  17. Quantum Computing

    NASA Astrophysics Data System (ADS)

    Steffen, Matthias

    2013-03-01

    Quantum mechanics plays a crucial role in many day-to-day products, and has been successfully used to explain a wide variety of observations in Physics. While some quantum effects such as tunneling limit the degree to which modern CMOS devices can be scaled to ever reducing dimensions, others may potentially be exploited to build an entirely new computing architecture: The quantum computer. In this talk I will review several basic concepts of a quantum computer. Why quantum computing and how do we do it? What is the status of several (but not all) approaches towards building a quantum computer, including IBM's approach using superconducting qubits? And what will it take to build a functional machine? The promise is that a quantum computer could solve certain interesting computational problems such as factoring using exponentially fewer computational steps than classical systems. Although the most sophisticated modern quantum computing experiments to date do not outperform simple classical computations, it is increasingly becoming clear that small scale demonstrations with as many as 100 qubits are beginning to be within reach over the next several years. Such a demonstration would undoubtedly be a thrilling feat, and usher in a new era of controllably testing quantum mechanics or quantum computing aspects. At the minimum, future demonstrations will shed much light on what lies ahead.

  18. Computer sciences

    NASA Technical Reports Server (NTRS)

    Smith, Paul H.

    1988-01-01

    The Computer Science Program provides advanced concepts, techniques, system architectures, algorithms, and software for both space and aeronautics information sciences and computer systems. The overall goal is to provide the technical foundation within NASA for the advancement of computing technology in aerospace applications. The research program is improving the state of knowledge of fundamental aerospace computing principles and advancing computing technology in space applications such as software engineering and information extraction from data collected by scientific instruments in space. The program includes the development of special algorithms and techniques to exploit the computing power provided by high performance parallel processors and special purpose architectures. Research is being conducted in the fundamentals of data base logic and improvement techniques for producing reliable computing systems.

  19. Computer software.

    PubMed

    Rosenthal, L E

    1986-10-01

    Software is the component in a computer system that permits the hardware to perform the various functions that a computer system is capable of doing. The history of software and its development can be traced to the early nineteenth century. All computer systems are designed to utilize the "stored program concept" as first developed by Charles Babbage in the 1850s. The concept was lost until the mid-1940s, when modern computers made their appearance. Today, because of the complex and myriad tasks that a computer system can perform, there has been a differentiation of types of software. There is software designed to perform specific business applications. There is software that controls the overall operation of a computer system. And there is software that is designed to carry out specialized tasks. Regardless of types, software is the most critical component of any computer system. Without it, all one has is a collection of circuits, transistors, and silicone chips. PMID:3536223

  20. Computer Literacy: Teaching Computer Ethics.

    ERIC Educational Resources Information Center

    Troutner, Joanne

    1986-01-01

    Suggests learning activities for teaching computer ethics in three areas: (1) equal access; (2) computer crime; and (3) privacy. Topics include computer time, advertising, class enrollments, copyright law, sabotage ("worms"), the Privacy Act of 1974 and the Freedom of Information Act of 1966. (JM)

  1. Technetium removal: preliminary flowsheet options

    SciTech Connect

    Eager, K.M.

    1995-10-24

    This document presents the results of a preliminary investigation into options for preliminary flowsheets for 99Tc removal from Hanford Site tank waste. A model is created to show the path of 99Tc through pretreatment to disposal. The Tank Waste Remediation (TWRS) flowsheet (Orme 1995) is used as a baseline. Ranges of important inputs to the model are developed, such as 99Tc inventory in the tanks and important splits through the TWRS flowsheet. Several technetium removal options are discussed along with sensitivities of the removal schemes to important model parameters

  2. PRELIMINARY DESIGN ANALYSIS OF AXIAL FLOW TURBINES

    NASA Technical Reports Server (NTRS)

    Glassman, A. J.

    1994-01-01

    A computer program has been developed for the preliminary design analysis of axial-flow turbines. Rapid approximate generalized procedures requiring minimum input are used to provide turbine overall geometry and performance adequate for screening studies. The computations are based on mean-diameter flow properties and a stage-average velocity diagram. Gas properties are assumed constant throughout the turbine. For any given turbine, all stages, except the first, are specified to have the same shape velocity diagram. The first stage differs only in the value of inlet flow angle. The velocity diagram shape depends upon the stage work factor value and the specified type of velocity diagram. Velocity diagrams can be specified as symmetrical, zero exit swirl, or impulse; or by inputting stage swirl split. Exit turning vanes can be included in the design. The 1991 update includes a generalized velocity diagram, a more flexible meanline path, a reheat model, a radial component of velocity, and a computation of free-vortex hub and tip velocity diagrams. Also, a loss-coefficient calibration was performed to provide recommended values for airbreathing engine turbines. Input design requirements include power or pressure ratio, mass flow rate, inlet temperature and pressure, and rotative speed. The design variables include inlet and exit diameters, stator angle or exit radius ratio, and number of stages. Gas properties are input as gas constant, specific heat ratio, and viscosity. The program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, flow angles, blading angles, and last stage absolute and relative Mach numbers. This program is written in FORTRAN 77 and can be ported to any computer with a standard FORTRAN compiler which supports NAMELIST. It was originally developed on an IBM 7000 series computer running VM and has been implemented on IBM PC computers and compatibles running MS-DOS under Lahey FORTRAN, and

  3. Computer Jet-Engine-Monitoring System

    NASA Technical Reports Server (NTRS)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1992-01-01

    "Intelligent Computer Assistant for Engine Monitoring" (ICAEM), computer-based monitoring system intended to distill and display data on conditions of operation of two turbofan engines of F-18, is in preliminary state of development. System reduces burden on propulsion engineer by providing single display of summary information on statuses of engines and alerting engineer to anomalous conditions. Effective use of prior engine-monitoring system requires continuous attention to multiple displays.

  4. A Computer-Based Dietary Counseling System.

    ERIC Educational Resources Information Center

    Slack, Warner V.; And Others

    1976-01-01

    The preliminary trial of a program in which principles of patient-computer dialogue have been applied to dietary counseling is described. The program was designed to obtain historical information from overweight patients and to provide instruction and guidance regarding dietary behavior. Beginning with a teaching sequence, 25 non-overweight…

  5. Computational psychiatry

    PubMed Central

    Montague, P. Read; Dolan, Raymond J.; Friston, Karl J.; Dayan, Peter

    2013-01-01

    Computational ideas pervade many areas of science and have an integrative explanatory role in neuroscience and cognitive science. However, computational depictions of cognitive function have had surprisingly little impact on the way we assess mental illness because diseases of the mind have not been systematically conceptualized in computational terms. Here, we outline goals and nascent efforts in the new field of computational psychiatry, which seeks to characterize mental dysfunction in terms of aberrant computations over multiple scales. We highlight early efforts in this area that employ reinforcement learning and game theoretic frameworks to elucidate decision-making in health and disease. Looking forwards, we emphasize a need for theory development and large-scale computational phenotyping in human subjects. PMID:22177032

  6. Computational aerothermodynamics

    NASA Technical Reports Server (NTRS)

    Deiwert, George S.; Green, Michael J.

    1987-01-01

    Computational aerothermodynamics (CAT) has in the past contributed to the understanding of real-gas flows encountered by hypervelocity reentry vehicles. With advances in computational fluid dynamics, in the modeling of high temperature phenomena, and in computer capability, CAT is an enabling technology for the design of many future space vehicles. An overview of the current capabilities of CAT is provided by describing available methods and their applications. Technical challenges that need to be met are discussed.

  7. Development of computer graphics

    SciTech Connect

    Nuttall, H.E.

    1989-07-01

    The purpose of this project was to screen and evaluate three graphics packages as to their suitability for displaying concentration contour graphs. The information to be displayed is from computer code simulations describing air-born contaminant transport. The three evaluation programs were MONGO (John Tonry, MIT, Cambridge, MA, 02139), Mathematica (Wolfram Research Inc.), and NCSA Image (National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign). After a preliminary investigation of each package, NCSA Image appeared to be significantly superior for generating the desired concentration contour graphs. Hence subsequent work and this report describes the implementation and testing of NCSA Image on both an Apple MacII and Sun 4 computers. NCSA Image includes several utilities (Layout, DataScope, HDF, and PalEdit) which were used in this study and installed on Dr. Ted Yamada`s Mac II computer. Dr. Yamada provided two sets of air pollution plume data which were displayed using NCSA Image. Both sets were animated into a sequential expanding plume series.

  8. Computer Software.

    ERIC Educational Resources Information Center

    Kay, Alan

    1984-01-01

    Discusses the nature and development of computer software. Programing, programing languages, types of software (including dynamic spreadsheets), and software of the future are among the topics considered. (JN)

  9. Computed Tomography

    NASA Astrophysics Data System (ADS)

    Castellano, Isabel; Geleijns, Jacob

    After its clinical introduction in 1973, computed tomography developed from an x-ray modality for axial imaging in neuroradiology into a versatile three dimensional imaging modality for a wide range of applications in for example oncology, vascular radiology, cardiology, traumatology and even in interventional radiology. Computed tomography is applied for diagnosis, follow-up studies and screening of healthy subpopulations with specific risk factors. This chapter provides a general introduction in computed tomography, covering a short history of computed tomography, technology, image quality, dosimetry, room shielding, quality control and quality criteria.

  10. Concentrating solar collector subsystem: Preliminary design package

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Preliminary design data are presented for a concentrating solar collector including an attitude controller. Provided are schedules, technical status, all documents required for preliminary design, and other program activities.