Science.gov

Sample records for computer controlled scanning

  1. Multipurpose computer-controlled scanning photometer

    SciTech Connect

    Kleckner, E.W.; Michalsky, J.J.; Smith, L.L.; Schmelzer, J.R.; Severtsen, R.H.; Berndt, J.L.

    1981-11-01

    This paper presents a design for a multipurpose computer-controlled scanning photometer capable of measuring optical radiation ranging in intensity from the subvisual light levels associated with night sky airglow emissions to the intense flux levels of direct sunlight. The instrument has twelve interference filters for wavelength selection, a 2.5/sup 0/ field of view for nighttime observations, and a 1.5/sup 0/ field of view for daytime observations. A photomultiplier tube is used as the low light-level detector, and a silicon-PIN photodiode serves as the insolation detector. A particular measurement sequence is programmed into the instrument and can be modified by reading a cassette tape in the field. Normal operation is fully automatic.

  2. Computer-controlled optical scanning tile microscope.

    PubMed

    Wang, C; Shumyatsky, P; Zeng, F; Zevallos, M; Alfano, R R

    2006-02-20

    A new type of computer-controlled optical scanning, high-magnification imaging system with a large field of view is described that overcomes the commonly believed incompatibility of achieving both high magnification and a large field of view. The new system incorporates galvanometer scanners, a CCD camera, and a high-brightness LED source for the fast acquisition of a large number of a high-resolution segmented tile images with a magnification of 800x for each tile. The captured segmented tile images are combined to create an effective enlarged view of a target totaling 1.6 mm x 1.2 mm in area. The speed and sensitivity of the system make it suitable for high-resolution imaging and monitoring of a small segmented area of 320 microm x 240 microm with 4 microm resolution. Each tile segment of the target can be zoomed up without loss of the high resolution. This new microscope imaging system gives both high magnification and a large field of view. This microscope can be utilized in medicine, biology, semiconductor inspection, device analysis, and quality control. PMID:16523776

  3. EVALUATION OF COMPUTER-CONTROLLED SCANNING ELECTRON MICROSCOPY APPLIED TO AN AMBIENT URBAN AEROSOL SAMPLE

    EPA Science Inventory

    Concerns about the environmental and public health effects of particulate matter (PM) have stimulated interest in analytical techniques capable of measuring the size and chemical composition of individual aerosol particles. Computer-controlled scanning electron microscopy (CCSE...

  4. Scanning computed confocal imager

    DOEpatents

    George, John S.

    2000-03-14

    There is provided a confocal imager comprising a light source emitting a light, with a light modulator in optical communication with the light source for varying the spatial and temporal pattern of the light. A beam splitter receives the scanned light and direct the scanned light onto a target and pass light reflected from the target to a video capturing device for receiving the reflected light and transferring a digital image of the reflected light to a computer for creating a virtual aperture and outputting the digital image. In a transmissive mode of operation the invention omits the beam splitter means and captures light passed through the target.

  5. Implementation on a desktop computer of the real time feedback control loop of a scanning probe microscope

    NASA Astrophysics Data System (ADS)

    Aloisi, G.; Bacci, F.; Carlà, M.; Dolci, D.; Lanzi, L.

    2008-11-01

    A software package has been developed to implement the real time feedback control loop needed in scanning probe microscopy on a general purpose desktop computer of the current high-speed/multicore generation. The main features of the implementation of both the feedback loop and the control of the experiment on the same computer are discussed. The package can work with several general purpose data acquisition boards and can be extended in a modular way to further board models; timing performance has been tested with several hardware configurations and some applications common in scanning probe microscopy. The package is available under an Open Source license.

  6. Characterization of combustion-derived individual fine particulates by computer-controlled scanning electron microscopy

    SciTech Connect

    Zhang, L.; Yu, D.X.; Yao, H.; Xu, M.H.; Wang, Q.Y.; Ninomiya, Y.

    2009-11-15

    Particulate matter (PM) emission from the combustion of solid fuels potentially poses a severe threat to the environment. In this article, a novel approach was developed to examine the properties of individual particles in PM. With this method, PM emitted from combustion was first size-segregated. Subsequently, each size was characterized by computer-controlled scanning electron microscopy (CCSEM) for both bulk property and single particle analysis. Combustion of bituminous coal, dried sewage sludge (DSS) and their mixture were conducted at 1200 {sup o}C in a laboratory-scale drop tube furnace. Three individual sizes smaller than 2.5 {mu}m were investigated. The results indicate that a prior size-segregation can greatly minimize the particle size contrast and phase contrast on the backscattered images during CCSEM analysis. Consequently, high accuracy can be achieved for quantifying the sub-micron particles and their inherent volatile metals. Regarding the PM properties as attained, concentrations of volatile metals including Na, K, and Zn have a negative relationship with particle size; they are enriched in the smallest particles around 0.11 {mu}m as studied here. Strong interactions can occur during the cofiring of coal and DSS, leading to the distinct properties of PM emitted from cofiring. The method developed here and results attained from it are helpful for management of the risks relating to PM emission during coal-fired boilers.

  7. Distinguishing respirable quartz in coal fly ash using computer-controlled scanning electron microscopy

    SciTech Connect

    Nick Cprek; Naresh Shah; Frank E. Huggins; Gerald P. Huffman

    2007-05-15

    Determination and classification of quartz in coal fly ash (CFA) is a subject of interest because of the adverse health effects caused by inhalation of crystalline silica. Workers with prolonged exposure to this carcinogen can develop respiratory diseases over time. This obviously may include utility plant workers involved in the handling, loading, and hauling of CFA. In this investigation, computer-controlled scanning electron microscopy (CCSEM) and X-ray diffraction (XRD) were used to investigate Si-rich phases in CFA to develop a better approach for the determination of respirable quartz. Three CFA samples from utility boilers and a NIST glass standard CFA sample were investigated. The XRD measurements indicated that the four samples contained from 7.0 to 16.0 wt.% of quartz. The CCSEM measurements utilized both particle size distributions and a particle shape parameter, circularity, to classify the Si-rich phases in these ashes as either crystalline or amorphous (glass). The results indicated that the amount of free, respirable, quartz in these CFA samples ranged from only 0.1-1.0 vol % and showed little correlation with the XRD results for the bulk ash. These results are significant in view of the fact that XRD is the traditional method of measuring crystalline silica in dust collected from workplace atmospheres. The results provide a better understanding of studies that indicate very little evidence of a link between human exposure to CFA and silicosis and lung cancer. 24 refs., 8 figs., 4 tabs.

  8. Distinguishing respirable quartz in coal fly ash using computer-controlled scanning electron microscopy.

    PubMed

    Cprek, Nick; Shah, Naresh; Huggins, Frank E; Huffman, Gerald P

    2007-05-15

    Determination and classification of quartz in coal fly ash (CFA) is a subject of interest because of the adverse health effects caused by inhalation of crystalline silica. Workers with prolonged exposure to this carcinogen can develop respiratory diseases over time. This obviously may include utility plant workers involved in the handling, loading, and hauling of CFA. In this investigation, computer-controlled scanning electron microscopy (CCSEM) and X-ray diffraction (XRD) were used to investigate Si-rich phases in CFA to develop a better approach for the determination of respirable quartz. Three CFA samples from utility boilers and a NIST standard CFA sample were investigated. The XRD measurements indicated that the four samples contained from 7.0 to 16.0 wt.% of quartz. The CCSEM measurements utilized both particle size distributions and a particle shape parameter, circularity, to classify the Si-rich phases in these ashes as either crystalline or amorphous (glass). The results indicated that the amount of free, respirable, quartz in these CFA samples ranged from only 0.1-1.0 vol % and showed little correlation with the XRD results for the bulk ash. These results are significant in view of the factthat XRD is the traditional method of measuring crystalline silica in dust collected from workplace atmospheres. PMID:17547166

  9. Computer control of a scanning electron microscope for digital image processing of thermal-wave images

    NASA Technical Reports Server (NTRS)

    Gilbert, Percy; Jones, Robert E.; Kramarchuk, Ihor; Williams, Wallace D.; Pouch, John J.

    1987-01-01

    Using a recently developed technology called thermal-wave microscopy, NASA Lewis Research Center has developed a computer controlled submicron thermal-wave microscope for the purpose of investigating III-V compound semiconductor devices and materials. This paper describes the system's design and configuration and discusses the hardware and software capabilities. Knowledge of the Concurrent 3200 series computers is needed for a complete understanding of the material presented. However, concepts and procedures are of general interest.

  10. Inductively coupled plasma-atomic emission spectroscopy: a computer controlled, scanning monochromator system for the rapid determination of the elements

    SciTech Connect

    Floyd, M.A.

    1980-03-01

    A computer controlled, scanning monochromator system specifically designed for the rapid, sequential determination of the elements is described. The monochromator is combined with an inductively coupled plasma excitation source so that elements at major, minor, trace, and ultratrace levels may be determined, in sequence, without changing experimental parameters other than the spectral line observed. A number of distinctive features not found in previously described versions are incorporated into the system here described. Performance characteristics of the entire system and several analytical applications are discussed.

  11. EVALUATION OF COMPUTER-CONTROLLED SCANNING ELECTRON MICROSCOPY APPLIED TO AN AMBIENT URBAN AEROSOL SAMPLE

    EPA Science Inventory


    Recent interest in monitoring and speciation of particulate matter has led to increased application of scanning electron microscopy (SEM) coupled with energy-dispersive x-ray analysis (EDX) to individual particle analysis. SEM/EDX provides information on the size, shape, co...

  12. Performance of Passive Samplers Analyzed by Computer-Controlled Scanning Electron Microscopy to Measure PM10-2.5.

    PubMed

    Peters, Thomas M; Sawvel, Eric J; Willis, Robert; West, Roger R; Casuccio, Gary S

    2016-07-19

    We report on the precision and accuracy of measuring PM10-2.5 and its components with particles collected by passive aerosol samplers and analyzed by computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy. Passive samplers were deployed for week-long intervals in triplicate and colocated with a federal reference method sampler at three sites and for 5 weeks in summer 2009 and 5 weeks in winter 2010 in Cleveland, OH. The limit of detection of the passive method for PM10-2.5 determined from blank analysis was 2.8 μg m(-3). Overall precision expressed as root-mean-square coefficient of variation (CVRMS) improved with increasing concentrations (37% for all samples, n = 30; 19% for PM10-2.5 > 10 μg m(-3), n = 9; and 10% for PM10-2.5 > 15 μg m(-3), n = 4). The linear regression of PM10-2.5 measured passively on that measured with the reference sampler exhibited an intercept not statistically different than zero (p = 0.46) and a slope not statistically different from unity (p = 0.92). Triplicates with high CVs (CV > 40%, n = 5) were attributed to low particle counts (and mass concentrations), spurious counts attributed to salt particles, and Al-rich particles. This work provides important quantitative observations that can help guide future development and use of passive samplers for measuring atmospheric particulate matter. PMID:27300163

  13. Computer controlled antenna system

    NASA Technical Reports Server (NTRS)

    Raumann, N. A.

    1972-01-01

    The application of small computers using digital techniques for operating the servo and control system of large antennas is discussed. The advantages of the system are described. The techniques were evaluated with a forty foot antenna and the Sigma V computer. Programs have been completed which drive the antenna directly without the need for a servo amplifier, antenna position programmer or a scan generator.

  14. A microprocessor controlled pressure scanning system

    NASA Technical Reports Server (NTRS)

    Anderson, R. C.

    1976-01-01

    A microprocessor-based controller and data logger for pressure scanning systems is described. The microcomputer positions and manages data from as many as four 48-port electro-mechanical pressure scanners. The maximum scanning rate is 80 pressure measurements per second (20 ports per second on each of four scanners). The system features on-line calibration, position-directed data storage, and once-per-scan display in engineering units of data from a selected port. The system is designed to be interfaced to a facility computer through a shared memory. System hardware and software are described. Factors affecting measurement error in this type of system are also discussed.

  15. A single photon emission computed tomography scan study of striatal dopamine D2 receptor binding with 123I-epidepride in patients with schizophrenia and controls.

    PubMed

    Tibbo, P; Silverstone, P H; McEwan, A J; Scott, J; Joshua, A; Golberg, K

    1997-01-01

    The usefulness of 123I-epidepride as a single photon emission computed tomography (SPECT) scan D2 receptor ligand was examined in vivo in 13 medicated patients with schizophrenia and age- and sex-matched normal controls. To establish the effect of endogenous dopamine on 123I-epidepride binding, 4 of the 13 controls also received 20 mg D-amphetamine. The results showed that 123I-epidepride had high specific binding to the striatum in both patients with schizophrenia and normal controls. There was a trend for the total striatal binding of medicated patients with schizophrenia, as measured by total basal ganglia: frontal cortex (TBG:FC) ratios, to be less than the binding of controls (P = 0.053). This trend confirms previous work showing that antipsychotic medication decreases the number of D2 receptors available for binding to the radioligand. Interestingly, there was also a significant relationship between 123I-epidepride binding ratios and global functioning scales (Global Assessment of Functioning scale [GAF]) for schizophrenia (r = 0.56, P = 0.045), although there was no such relationship with the Brief Psychiatric Rating Scale (BPRS). In addition, our results showed that amphetamine-induced dopamine release did not alter 123I-epidepride binding, confirming the high specific binding of 123I-epidepride to the D2 receptor. We conclude that 123I-epidepride appears to be a very useful SPECT ligand for imaging the D2 receptor. PMID:9002391

  16. Quaternions for Galileo scan platform control

    NASA Technical Reports Server (NTRS)

    Breckenridge, W. G.; Man, G. K.

    1984-01-01

    The application of quaternions for the articulation control of the Galileo scan platform is presented in this paper. The purpose of selecting quaternions is to minimize onboard computation time and program size. Attention has been focused on performing inertial pointing while the spacecraft is in a dual spin configuration. Target quaternion and relative target quaternion are introduced and used to specify the target position of the scan platform for point-to-point absolute slews and mosaic relative slews, respectively. The pointing error of the platform is represented by an error quaternion which is converted into gimbal angular errors defining the attitude change. For path control, a moving target quaternion is generated; the corresponding tracking error quaternion and the related spacecraft motion compensation capability are also addressed. A sample slew case is used to demonstrate the implementation of these concepts.

  17. Scanning Transmission X-ray Microscope Control Program

    Energy Science and Technology Software Center (ESTSC)

    2005-08-05

    User Interface and control software or C++ to run on specifically equipped computer running Windows Operating Systems. Program performs specific control functions required to operate Interferometer controlled scanning transmission X-ray microscopes at ALS beamlines 532 and 11.0.2. Graphical user interface facilitates control, display images and spectra.

  18. Chemical Characterization of Outdoor and Subway Fine (PM2.5-1.0) and Coarse (PM10-2.5) Particulate Matter in Seoul (Korea) Computer-Controlled Scanning Electron Microscopy (CCSEM)

    EPA Science Inventory

    Outdoor and indoor (subway) samples were collected by passive sampling in urban Seoul and analyzed with computer-controlled scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (CCSEM-EDX). Soil/road dust particles accounted for 42-60% (by weight) of fin...

  19. Postoperative myocardial infarction documented by technetium pyrophosphate scan using single-photon emission computed tomography: Significance of intraoperative myocardial ischemia and hemodynamic control

    SciTech Connect

    Cheng, D.C.; Chung, F.; Burns, R.J.; Houston, P.L.; Feindel, C.M. )

    1989-12-01

    The aim of this prospective study was to document postoperative myocardial infarction (PMI) by technetium pyrophosphate scan using single-photon emission computed tomography (TcPPi-SPECT) in 28 patients undergoing elective coronary bypass grafting (CABG). The relationships of intraoperative electrocardiographic myocardial ischemia, hemodynamic responses, and pharmacological requirements to this incidence of PMI were correlated. Radionuclide cardioangiography and TcPPi-SPECT were performed 24 h preoperatively and 48 h postoperatively. A standard high-dose fentanyl anesthetic protocol was used. Twenty-five percent of elective CABG patients were complicated with PMI, as documented by TcPPi-SPECT with an infarcted mass of 38.0 +/- 5.5 g. No significant difference in demographic, preoperative right and left ventricular function, number of coronary vessels grafted, or aortic cross-clamp time was observed between the PMI and non-PMI groups. The distribution of patients using preoperative beta-adrenergic blocking drugs or calcium channel blocking drugs was found to have no correlation with the outcome of PMI. As well, no significant differences in hemodynamic changes or pharmacological requirements were observed in the PMI and non-PMI groups during prebypass or postbypass periods, indicating careful intraoperative control of hemodynamic indices did not prevent the outcome of PMI in these patients. However, the incidence of prebypass ischemia was 39.3% and significantly correlated with the outcome of positive TcPPi-SPECT, denoting a 3.9-fold increased risk of developing PMI. Prebypass ischemic changes in leads II and V5 were shown to correlate with increased CPK-MB release (P less than 0.05) and tends to occur more frequently with lateral myocardial infarction.

  20. Computer-controlled spot-scan imaging of crotoxin complex crystals with 400 keV electrons at near-atomic resolution.

    PubMed

    Brink, J; Chiu, W; Dougherty, M

    1992-10-01

    400 keV electrons yield a better relative image contrast than 100 keV electrons for a beam-sensitive organic crystal when spot-scan imaging is used [J. Brink and W. Chiu, J. Microscopy 161 (1991) 279]. A FORTRAN 77 program has been written to operate the spot-scan imaging system on a computer workstation under the VMS operating system which is interfaced serially to the JEOL4000 electron microscope. We demonstrate the application of this implementation by imaging crotoxin complex crystals embedded in either vitreous ice or glucose to 2.5 A resolution. The intensity strength of the structure factors of this protein crystal are different at low (> 10 A) resolution but similar at high resolution (< 10 A) for the two embedding media as expected from their scattering contrast difference. Based on our experience as judged from the electron diffraction patterns of highly tilted crystals, flat crystals embedded in glucose can be readily obtained. Furthermore, our spot-scan imaging system also has the option of correcting the focus gradient that is present in images of tilted specimens. PMID:1481273

  1. Evolution of the Cranial Computed Tomography Scan in Child Abuse.

    ERIC Educational Resources Information Center

    Feldman, Kenneth W.; And Others

    1995-01-01

    A retrospective review of medical charts for 34 children with a diagnosis of child abuse, who had cranial computed tomography scans performed, revealed that some scans initially interpreted as normal were subsequently reinterpreted as abnormal, and some children's repeat scannings were interpreted as abnormal, modifying the medical and legal…

  2. Tuning and scanning control system for high resolution alexandrite lasers

    NASA Technical Reports Server (NTRS)

    Smith, James C.; Schwemmer, Geary K.

    1988-01-01

    An alexandrite laser is spectrally narrowed and tuned by the use of three optical elements. Each element provides a successively higher degree of spectral resolution. The digitally controlled tuning and scanning control servo system simultaneously positions all three optical elements to provide continuous high resolution laser spectral tuning. The user may select manual, single, or continuous modes of automated scanning of ranges up to 3.00/cm and at scan rates up to 3.85/cm/min. Scanning over an extended range of up to 9.999/cm may be achieved if the highest resolution optic is removed from the system. The control system is also capable of being remotely operated by another computer or controller via standard RS-232 serial data link.

  3. SCAN+

    SciTech Connect

    Kenneth Krebs, John Svoboda

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determine the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.

  4. Computationally efficient control allocation

    NASA Technical Reports Server (NTRS)

    Durham, Wayne (Inventor)

    2001-01-01

    A computationally efficient method for calculating near-optimal solutions to the three-objective, linear control allocation problem is disclosed. The control allocation problem is that of distributing the effort of redundant control effectors to achieve some desired set of objectives. The problem is deemed linear if control effectiveness is affine with respect to the individual control effectors. The optimal solution is that which exploits the collective maximum capability of the effectors within their individual physical limits. Computational efficiency is measured by the number of floating-point operations required for solution. The method presented returned optimal solutions in more than 90% of the cases examined; non-optimal solutions returned by the method were typically much less than 1% different from optimal and the errors tended to become smaller than 0.01% as the number of controls was increased. The magnitude of the errors returned by the present method was much smaller than those that resulted from either pseudo inverse or cascaded generalized inverse solutions. The computational complexity of the method presented varied linearly with increasing numbers of controls; the number of required floating point operations increased from 5.5 i, to seven times faster than did the minimum-norm solution (the pseudoinverse), and at about the same rate as did the cascaded generalized inverse solution. The computational requirements of the method presented were much better than that of previously described facet-searching methods which increase in proportion to the square of the number of controls.

  5. Computer aided manipulator control

    NASA Technical Reports Server (NTRS)

    Bejczy, A. K.; Zawacki, R. L.

    1980-01-01

    This paper describes the hardware and software system of a dedicated mini- and microcomputer network developed at the JPL teleoperator project to aid the operator in real-time control of remote manipulators. The operator can be in series or in parallel with the control computer during operation. The purpose of the project is to develop, demonstrate and evaluate advanced supervisory control concepts and techniques for space applications. The paper concludes with a brief outline of future development plans and issues.

  6. The vertex scan: an important component of cranial computed tomography.

    PubMed

    Wing, S D; Osborn, A G; Wing, R W

    1978-04-01

    Physicians who monitor cranial computed tomography occasionally omit the most superior aspects of the brain and calvarium because of time limitations and overloaded scanning schedules. In addition, standardized CT reporting forms as well training literature distributed by some manufacturers support the concept that a complete CT series consists of three scan pairs. Omission of a vertex scan pair results in failure to visualize 10%-15% of the brain volume. We have reviewed the results of 2,000 consecutive CT studies to determine the number and variety of pathologic entities that would have been missed had a vertex scan not been obtained. The most significant or sole abnormality was present on the vertex scan alone in 3% of the cases. Examples are presented. A true vertex levels should be obtained in every routine CT examination. PMID:416693

  7. Computational fluid dynamic control

    NASA Technical Reports Server (NTRS)

    Hartley, Tom T.; Deabreu-Garcia, Alex

    1989-01-01

    A general technique is presented for modeling fluid, or gas, dynamic systems specifically for the development of control systems. The numerical methods which are generally used in computational fluid dynamics are borrowed to create either continuous-time or discrete-time models of the particular fluid system. The resulting equations can be either left in a nonlinear form, or easily linearized about an operating point. As there are typically very many states in these systems, the usual linear model reduction methods can be used on them to allow a low-order controller to be designed. A simple example is given which typifies many internal flow control problems. The resulting control is termed computational fluid dynamic control.

  8. SCAN+

    Energy Science and Technology Software Center (ESTSC)

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determinemore » the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.« less

  9. Optimal control computer programs

    NASA Technical Reports Server (NTRS)

    Kuo, F.

    1992-01-01

    The solution of the optimal control problem, even with low order dynamical systems, can usually strain the analytical ability of most engineers. The understanding of this subject matter, therefore, would be greatly enhanced if a software package existed that could simulate simple generic problems. Surprisingly, despite a great abundance of commercially available control software, few, if any, address the part of optimal control in its most generic form. The purpose of this paper is, therefore, to present a simple computer program that will perform simulations of optimal control problems that arise from the first necessary condition and the Pontryagin's maximum principle.

  10. General purpose control system for scanning laser ophthalmoscopes.

    PubMed

    Cushion, John; Reinholz, Fred N; Patterson, Brett A

    2003-06-01

    A flexible control system for scanning laser ophthalmoscopes is described that is quick and simple to configure, easily modified or adapted, and containing many useful features. The system facilitates adjustment of several parameters to account for changes to the scan position, ambient light and temperature, including both optical and electronic components, which is otherwise difficult and time-consuming to perform. The system is portable and uses custom-designed printed circuit boards. All system parameters, such as focus, scan rate,scan depth and stereo control can be digitally controlled from a computer via a single serial port. Custom software allows changes to any system parameters by simply sending the required control data to the rack. The circuit boards in the system are multilayer,incorporating good ground-plane techniques to minimize noise, programmable logic and semicustom logic for low cost and compact size, and microcontrollers with embedded firm ware for flexible operation. Retinal images demonstrate that the system performs well. PMID:12786776

  11. Propulsion controlled aircraft computer

    NASA Technical Reports Server (NTRS)

    Cogan, Bruce R. (Inventor)

    2010-01-01

    A low-cost, easily retrofit Propulsion Controlled Aircraft (PCA) system for use on a wide range of commercial and military aircraft consists of an propulsion controlled aircraft computer that reads in aircraft data including aircraft state, pilot commands and other related data, calculates aircraft throttle position for a given maneuver commanded by the pilot, and then displays both current and calculated throttle position on a cockpit display to show the pilot where to move throttles to achieve the commanded maneuver, or is automatically sent digitally to command the engines directly.

  12. Impedance feedback control for scanning electrochemical microscopy.

    PubMed

    Alpuche-Aviles, M A; Wipf, D O

    2001-10-15

    A new constant-distance imaging method based on the relationship between tip impedance and tip-substrate separation has been developed for the scanning electrochemical microscope. The tip impedance is monitored by application of a high-frequency ac voltage bias between the tip and auxiliary electrode. The high-frequency ac current is easily separated from the dc-level faradaic electrochemistry with a simple RC filter, which allows impedance measurements during feedback or generation/collection experiments. By employing a piezo-based feedback controller, we are able to maintain the impedance at a constant value and, thus, maintain a constant tip-substrate separation. Application of the method to feedback and generation/collection experiments with tip electrodes as small as 2 microm is presented. PMID:11681463

  13. A computer program for scanning transmission ion microscopy simulation

    NASA Astrophysics Data System (ADS)

    Wu, R.; Shen, H.; Mi, Y.; Sun, M. D.; Yang, M. J.

    2005-04-01

    With the installation of the Scanning Proton Microprobe system at Fudan University, we are in the process of developing a three-dimension reconstruction technique based on scanning transmission ion microscopy-computed tomography (STIM-CT). As the first step, a related computer program of STIM simulation has been established. This program is written in the Visual C++®, using the technique of OOP (Object Oriented Programming) and it is a standard multiple-document Windows® program. It can be run with all MS Windows® operating systems. The operating mode is the menu mode, using a multiple process technique. The stopping power theory is based on the Bethe-Bloch formula. In order to simplify the calculation, the improved cylindrical coordinate model was introduced in the program instead of a usual spherical or cylindrical coordinate model. The simulated results of a sample at several rotation angles are presented.

  14. Dynamic computed tomographic scans in experimental brain abscess.

    PubMed

    Enzmann, D R; Placone, R C; Britt, R H

    1984-01-01

    Dynamic computed tomographic scans were performed in an experimental brain abscess model to establish criteria that could be utilized in abscess staging. The vascular phase of the time-density curves did not differentiate cerebritis and capsule stages. The amount of residual enhancement after the first pass of an intra-arterial contrast bolus differed between major abscess stages, the greater residual enhancement being noted in the capsule stage. PMID:6462439

  15. Cosmetic and aesthetic skin photosurgery using a computer-assisted CO2 laser-scanning system

    NASA Astrophysics Data System (ADS)

    Dutu, Doru C. A.; Dumitras, Dan C.; Nedelcu, Ioan; Ghetie, Sergiu D.

    1997-12-01

    Since the first application of CO2 laser in skin photosurgery, various techniques such as laser pulsing, beam scanning and computer-assisted laser pulse generator have been introduced for the purpose of reducing tissue carbonization and thermal necrosis. Using a quite simple XY optical scanner equipped with two galvanometric driven mirrors and an appropriate software to process the scanning data and control the interaction time and energy density in the scanned area, we have obtained a device which can improve CO2 laser application in cosmetic and aesthetic surgery. The opto-mechanical CO2 laser scanner based on two total reflecting flat mirrors placed at 90 degree(s) in respect to the XY scanning directions and independently driven through a magnetic field provides a linear movement of the incident laser beam in the operating field. A DA converter supplied with scanning data by the software enables a scanning with linearity better than 1% for a maximum angular deviation of 20 degree(s). Because the scanning quality of the laser beam in the operating field is given not only by the displacement function of the two mirrors, but also by the beam characteristics in the focal plane and the cross distribution in the laser beam, the surgeon can control through software either the scanning field dimensions or the distance between two consecutive points of the vertically and/or horizontally sweep line. The development of computer-assisted surgical scanning techniques will help control the surgical laser, to create either a reproducible incision with a controlled depth or a controlled incision pattern with minimal incision width, a long desired facility for plastic surgery, neurosurgery, ENT and dentistry.

  16. Apparatus for controlling the scan width of a scanning laser beam

    DOEpatents

    Johnson, Gary W.

    1996-01-01

    Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board.

  17. Apparatus for controlling the scan width of a scanning laser beam

    DOEpatents

    Johnson, G.W.

    1996-10-22

    Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board. 8 figs.

  18. Chemical characterization of outdoor and subway fine (PM(2.5-1.0)) and coarse (PM(10-2.5)) particulate matter in Seoul (Korea) by computer-controlled scanning electron microscopy (CCSEM).

    PubMed

    Byeon, Sang-Hoon; Willis, Robert; Peters, Thomas M

    2015-02-01

    Outdoor and indoor (subway) samples were collected by passive sampling in urban Seoul (Korea) and analyzed with computer-controlled scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (CCSEM-EDX). Soil/road dust particles accounted for 42%-60% (by weight) of fine particulate matter larger than 1 µm (PM(2.5-1.0)) in outdoor samples and 18% of PM2.5-1.0 in subway samples. Iron-containing particles accounted for only 3%-6% in outdoor samples but 69% in subway samples. Qualitatively similar results were found for coarse particulate matter (PM(10-2.5)) with soil/road dust particles dominating outdoor samples (66%-83%) and iron-containing particles contributing most to subway PM(10-2.5) (44%). As expected, soil/road dust particles comprised a greater mass fraction of PM(10-2.5) than PM(2.5-1.0). Also as expected, the mass fraction of iron-containing particles was substantially less in PM(10-2.5) than in PM(2.5-1.0). Results of this study are consistent with known emission sources in the area and with previous studies, which showed high concentrations of iron-containing particles in the subway compared to outdoor sites. Thus, passive sampling with CCSEM-EDX offers an inexpensive means to assess PM(2.5-1.0) and PM(10-2.5) simultaneously and by composition at multiple locations. PMID:25689348

  19. Additive Manufacturing of Anatomical Models from Computed Tomography Scan Data.

    PubMed

    Gür, Y

    2014-12-01

    The purpose of the study presented here was to investigate the manufacturability of human anatomical models from Computed Tomography (CT) scan data via a 3D desktop printer which uses fused deposition modelling (FDM) technology. First, Digital Imaging and Communications in Medicine (DICOM) CT scan data were converted to 3D Standard Triangle Language (STL) format by using In Vaselius digital imaging program. Once this STL file is obtained, a 3D physical version of the anatomical model can be fabricated by a desktop 3D FDM printer. As a case study, a patient's skull CT scan data was considered, and a tangible version of the skull was manufactured by a 3D FDM desktop printer. During the 3D printing process, the skull was built using acrylonitrile-butadiene-styrene (ABS) co-polymer plastic. The printed model showed that the 3D FDM printing technology is able to fabricate anatomical models with high accuracy. As a result, the skull model can be used for preoperative surgical planning, medical training activities, implant design and simulation to show the potential of the FDM technology in medical field. It will also improve communication between medical stuff and patients. Current result indicates that a 3D desktop printer which uses FDM technology can be used to obtain accurate anatomical models. PMID:26336695

  20. Interferometric Synthetic Aperture Microscopy: Computed Imaging for Scanned Coherent Microscopy.

    PubMed

    Davis, Brynmor J; Marks, Daniel L; Ralston, Tyler S; Carney, P Scott; Boppart, Stephen A

    2008-06-01

    Three-dimensional image formation in microscopy is greatly enhanced by the use of computed imaging techniques. In particular, Interferometric Synthetic Aperture Microscopy (ISAM) allows the removal of out-of-focus blur in broadband, coherent microscopy. Earlier methods, such as optical coherence tomography (OCT), utilize interferometric ranging, but do not apply computed imaging methods and therefore must scan the focal depth to acquire extended volumetric images. ISAM removes the need to scan the focus by allowing volumetric image reconstruction from data collected at a single focal depth. ISAM signal processing techniques are similar to the Fourier migration methods of seismology and the Fourier reconstruction methods of Synthetic Aperture Radar (SAR). In this article ISAM is described and the close ties between ISAM and SAR are explored. ISAM and a simple strip-map SAR system are placed in a common mathematical framework and compared to OCT and radar respectively. This article is intended to serve as a review of ISAM, and will be especially useful to readers with a background in SAR. PMID:20948975

  1. Interferometric Synthetic Aperture Microscopy: Computed Imaging for Scanned Coherent Microscopy

    PubMed Central

    Davis, Brynmor. J.; Marks, Daniel. L.; Ralston, Tyler. S.; Carney, P. Scott; Boppart, Stephen. A.

    2008-01-01

    Three-dimensional image formation in microscopy is greatly enhanced by the use of computed imaging techniques. In particular, Interferometric Synthetic Aperture Microscopy (ISAM) allows the removal of out-of-focus blur in broadband, coherent microscopy. Earlier methods, such as optical coherence tomography (OCT), utilize interferometric ranging, but do not apply computed imaging methods and therefore must scan the focal depth to acquire extended volumetric images. ISAM removes the need to scan the focus by allowing volumetric image reconstruction from data collected at a single focal depth. ISAM signal processing techniques are similar to the Fourier migration methods of seismology and the Fourier reconstruction methods of Synthetic Aperture Radar (SAR). In this article ISAM is described and the close ties between ISAM and SAR are explored. ISAM and a simple strip-map SAR system are placed in a common mathematical framework and compared to OCT and radar respectively. This article is intended to serve as a review of ISAM, and will be especially useful to readers with a background in SAR. PMID:20948975

  2. Computer Software for Process Control.

    ERIC Educational Resources Information Center

    Spector, Alfred Z.

    1984-01-01

    Computer software for process control has the primary function of communicating with and governing physical devices. The structure of such software, process-control systems, multitask systems, message passing, problems of deadlock, distributed computer systems, and protection against failure in process-control systems are among the areas examined.…

  3. Chemical Characterization of Outdoor and Subway Fine (PM2.5–1.0) and Coarse (PM10–2.5) Particulate Matter in Seoul (Korea) by Computer-Controlled Scanning Electron Microscopy (CCSEM)

    PubMed Central

    Byeon, Sang-Hoon; Willis, Robert; Peters, Thomas M.

    2015-01-01

    Outdoor and indoor (subway) samples were collected by passive sampling in urban Seoul (Korea) and analyzed with computer-controlled scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (CCSEM-EDX). Soil/road dust particles accounted for 42%–60% (by weight) of fine particulate matter larger than 1 µm (PM2.5–1.0) in outdoor samples and 18% of PM2.5–1.0 in subway samples. Iron-containing particles accounted for only 3%–6% in outdoor samples but 69% in subway samples. Qualitatively similar results were found for coarse particulate matter (PM10–2.5) with soil/road dust particles dominating outdoor samples (66%–83%) and iron-containing particles contributing most to subway PM10–2.5 (44%). As expected, soil/road dust particles comprised a greater mass fraction of PM10–2.5 than PM2.5–1.0. Also as expected, the mass fraction of iron-containing particles was substantially less in PM10–2.5 than in PM2.5–1.0. Results of this study are consistent with known emission sources in the area and with previous studies, which showed high concentrations of iron-containing particles in the subway compared to outdoor sites. Thus, passive sampling with CCSEM-EDX offers an inexpensive means to assess PM2.5–1.0 and PM10-2.5 simultaneously and by composition at multiple locations. PMID:25689348

  4. A novel multimodal laser scanning microscope control system

    NASA Astrophysics Data System (ADS)

    Lai, Zhenhua; Gu, Zetong; Karasek, Stephen; McLean, James; Zhang, Xi; DiMarzio, Charles; Yin, Jihao; Xiong, Daxi

    2015-03-01

    Traditional laser scanning microscopes require complex control systems to synchronize and control image acquisition. The control system is especially cumbersome in the multimodal laser scanning microscope. We have developed a novel multimodal laser scanning microscope control system based on a National Instruments multifunction data acquisition device (DAQ), which serves as both a data acquisition device and a programmable signal generator. The novel control system is low-cost and easy-to-build, with all components off-the-shelf. We have applied the control system in a multimodal laser scanning microscope. The control system has not only significantly decreased the complexity of the microscope, but also increased the system flexibility. We have demonstrated that the system can be easily customized for various applications.

  5. Control theory for scanning probe microscopy revisited.

    PubMed

    Stirling, Julian

    2014-01-01

    We derive a theoretical model for studying SPM feedback in the context of control theory. Previous models presented in the literature that apply standard models for proportional-integral-derivative controllers predict a highly unstable feedback environment. This model uses features specific to the SPM implementation of the proportional-integral controller to give realistic feedback behaviour. As such the stability of SPM feedback for a wide range of feedback gains can be understood. Further consideration of mechanical responses of the SPM system gives insight into the causes of exciting mechanical resonances of the scanner during feedback operation. PMID:24778957

  6. Control theory for scanning probe microscopy revisited

    PubMed Central

    2014-01-01

    Summary We derive a theoretical model for studying SPM feedback in the context of control theory. Previous models presented in the literature that apply standard models for proportional-integral-derivative controllers predict a highly unstable feedback environment. This model uses features specific to the SPM implementation of the proportional-integral controller to give realistic feedback behaviour. As such the stability of SPM feedback for a wide range of feedback gains can be understood. Further consideration of mechanical responses of the SPM system gives insight into the causes of exciting mechanical resonances of the scanner during feedback operation. PMID:24778957

  7. Computer Control For Ion Engines

    NASA Technical Reports Server (NTRS)

    Brophy, John R.

    1989-01-01

    Computer system controls start-up, steady-state operation, throttling, and shutdown of pair of xenon-ion propulsion engines. Controls direction of thrust of each engine through operation of gimbal stepping motors. Controls valves in propellant-storage and propellant-distribution system. Control software establishes and maintains efficient, stable operation over entire range of operating variables, and throttles engines to any point within range. Computer operates power supplies, valves, and flow controllers of two ion engines, ion-neutralizer subsystem, and other equipment. Designed for use in interplanetary flight, system adaptable to industrial use in ion-beam deposition of thin films.

  8. Scanning ablation of root caries with acoustic feedback control

    NASA Astrophysics Data System (ADS)

    Fan, Kenneth; Fried, Daniel

    2007-02-01

    It has been previously demonstrated that short λ=355-nm laser pulses can be used for the selective removal of caries lesions and composite restorative materials from occlusal surfaces with minimal damage to the peripheral sound tooth structure. One advantage of laser-systems is they can be integrated with acoustic and optical feedback systems for the automated discrimination of dental caries and restorative materials. The objective of this study was to test the hypothesis that root caries could be selectively removed from tooth surfaces using a computer controlled laserscanning system coupled with an acoustic feedback system. Dental root caries surfaces on extracted teeth were scanned with λ=355-nm laser pulses at irradiation intensities ranging from 0.6 to 0.8 J/cm2. Acoustic feedback signals were acquired and used to control the laser output and scanning stages were used to position the laser over carious dentin until all the caries were removed to a fixed depth. Polarization optical coherence tomography (PSOCT) was used to acquire images of the root caries lesions before and after removal by the laser in order to assess if ablation was selective. The amplitude of the acoustic waves generated during the ablation of carious dentin was higher than for sound dentin allowing the acoustic feedback system to discriminate between sound and carious dentin. PS-OCT showed that caries were removed to a depth of up to 1.5-mm with minimal peripheral damage to peripheral sound dentin. The acoustic feedback was successfully used to distinguish between root caries and sound dentin, enabling the selective removal of caries from dentin surfaces using a λ=355-nm, Nd:YAG Q-switched laser system.

  9. Scanning probe microscope simulator for the assessment of noise in scanning probe microscopy controllers

    SciTech Connect

    Wutscher, T.; Niebauer, J.; Giessibl, F. J.

    2013-07-15

    We present an electronic circuit that allows to calibrate and troubleshoot scanning probe microscopy (SPM) controllers with respect to their noise performance. The control signal in an SPM is typically highly nonlinear—the tunneling current in scanning tunneling microscopy (STM) varies exponentially with distance. The exponential current-versus-voltage characteristics of diodes allow to model the current dependence in STM. Additional inputs allow to simulate the effects of external perturbations and the reactions of the control electronics. We characterized the noise performance of the feedback controller using the apparent topography roughness of recorded images. For a comparison of different STM controllers, an optimal gain parameter was determined by exploring settling times through a rectangular perturbation signal. We used the circuit to directly compare the performance of two types of SPM controllers used in our laboratory.

  10. Scanning probe microscope simulator for the assessment of noise in scanning probe microscopy controllers.

    PubMed

    Wutscher, T; Niebauer, J; Giessibl, F J

    2013-07-01

    We present an electronic circuit that allows to calibrate and troubleshoot scanning probe microscopy (SPM) controllers with respect to their noise performance. The control signal in an SPM is typically highly nonlinear-the tunneling current in scanning tunneling microscopy (STM) varies exponentially with distance. The exponential current-versus-voltage characteristics of diodes allow to model the current dependence in STM. Additional inputs allow to simulate the effects of external perturbations and the reactions of the control electronics. We characterized the noise performance of the feedback controller using the apparent topography roughness of recorded images. For a comparison of different STM controllers, an optimal gain parameter was determined by exploring settling times through a rectangular perturbation signal. We used the circuit to directly compare the performance of two types of SPM controllers used in our laboratory. PMID:23902073

  11. Nanoscale plasmonic devices for dynamically controllable beam focusing and scanning

    NASA Astrophysics Data System (ADS)

    Çetin, A. E.; Sennaroglu, A.; Müstecaplıoğlu, Ö. E.

    2010-01-01

    We have performed simulations to investigate the variable focusing and scanning capability of metallic nano-slit configurations. In a symmetric nanorod configuration inside an aperture with adjustable offset of the center rod, the focal position is found to be variable in the 0.5-3.5 μm range. In a ladder configuration of the rods, the transmitted beam is found to be deflected up to 23°. Horizontal displacement of rods allows for finer control of angular scanning up to 4°. Such slit geometries offer the potential to be controlled by using nano-positioning systems for applications in dynamic beam shaping and scanning on the nanoscale.

  12. [Optimization of the chest computed tomography scan by varying the position of the arms].

    PubMed

    Matsumoto, Yoriaki; Masuda, Takanori; Imada, Naoyuki; Maruyama, Naoya; Inada, Satoshi; Ishibashi, Tooru; Satou, Tomoyasu

    2012-01-01

    Computed tomography automatic exposure control (CT-AEC) technique is calculated from a localizer radiograph. When we perform neck and chest CT examination, at first, we acquire localizer radiograph and neck images by placing the arm in a lowered position. Next, the arm is raised for the chest scan. Therefore, the localizer radiograph and subject information are different in the chest scan. In this situation, the chest scan with the use of the CT-AEC causes radiation over-dose. The purpose of this study is to optimize the CT-AEC by controlling noise index (NI), and make a chest CT scan condition considering the position of the arms. We measured the image noise (SD) in the phantom by using CT-AEC. In addition, dose length product (DLP) was recorded. Moreover, we examined the correlation with the clinical images. The results of our experiments show that radiation dose can be reduced with the image quality kept by controlling NI. PMID:22821158

  13. Search space scanning with planar electronically-controlled array antennas

    NASA Astrophysics Data System (ADS)

    Hanle, E.

    The demands which radar installations have to satisfy are rising with increasing traffic density in the case of civil applications and a growing threat level in the case of the military sector. In many instances, these demands can only be met by adapting the value of the transmitted power to the traffic density or the magnitude of the threat. Such an approach requires the employment of computer-aided radar systems with electronically-controlled antennas. The considered systems have currently also advantages with respect to reliability and cost effectiveness. The present investigation is concerned with suitable procedures for the improvement of the energy management, taking into account mainly aspects of radar control and signal processing. The discussion is based on the consideration of a planar array antenna. Differences arising in connection with the use of other types of antennas are also briefly examined. The employment of an immobile radar antenna for ground-based airspace observation is considered. Attention is given to the appropriate selection of the width of the lobe, the scanning, the tilt of the antenna, and antenna performance characteristics.

  14. Spacelab data analysis using the space plasma computer analysis network (SCAN) system

    NASA Technical Reports Server (NTRS)

    Green, J. L.

    1984-01-01

    The Space-plasma Computer Analysis Network (SCAN) currently connects a large number of U.S. Spacelab investigators into a common computer network. Used primarily by plasma physics researchers at present, SCAN provides access to Spacelab investigators in other areas of space science, to Spacelab and non-Spacelab correlative data bases, and to large Class VI computational facilities for modeling. SCAN links computers together at remote institutions used by space researchers, utilizing commercially available software for computer-to-computer communications. Started by the NASA's Office of Space Science in mid 1980, SCAN presently contains ten system nodes located at major universities and space research laboratories, with fourteen new nodes projected for the near future. The Stanford University computer gateways allow SCAN users to connect onto the ARPANET and TELENET overseas networks.

  15. Pointing and Scanning Control of Instruments Using Rotating Unbalanced Masses

    NASA Technical Reports Server (NTRS)

    Hung, John Y.

    1996-01-01

    Motions of telescopes, satellites, and other flight bodies have been controlled by various means in the past. For example, gimbal mounted devices can use electric motors to produce pointing and scanning motions. Reaction wheels, control moment gyros, and propellant-charged reaction jets are other technologies that have also been used. Each of these methods has its advantages, but all actuator systems used in a flight environment face the challenges of minimizing weight, reducing energy consumption, and maximizing reliability. Recently, Polites invented and patented the Rotating Unbalanced Mass (RUM) device as a means for generation scanning motion on flight experiments. RUM devices have been successfully used to generate various scanning motions. The basic principle: a RUM rotating at constant annular velocity exerts a cyclic centrifugal force on the instrument or main body, thus producing a periodic scanning motion. A system of RUM devices exerts no reaction forces on the main body, requires very little energy, and is very simple to construct and control. These are significant advantages over electric motors, reaction wheels, and control moment gyroscopes. Although the RUM device very easily produces scanning motion, an auxiliary control system may be required to maintain the proper orientation, or pointing of the main body. It has been suggested that RUM devices can be used to control pointing dynamics, as well as generate the desired periodic scanning motion. The idea is that the RUM velocity will not be constant, but will vary over the period of one RUM rotation. The thought is that the changing angular velocity produces a centrifugal force having time-varying magnitude and direction. The scope of the present research project is to further study the pointing control concept, and to implement a microcontroller program to control an experimental hardware system. This report is subdivided into three themes. The basic dynamic modeling and control principles are

  16. Comparison of Image Quality and Radiation Dose of Coronary Computed Tomography Angiography Between Conventional Helical Scanning and a Strategy Incorporating Sequential Scanning

    PubMed Central

    Einstein, Andrew J.; Wolff, Steven D.; Manheimer, Eric D.; Thompson, James; Terry, Sylvia; Uretsky, Seth; Pilip, Adalbert; Peters, M. Robert

    2009-01-01

    Radiation dose from coronary computed tomography angiography may be reduced using a sequential scanning protocol rather than a conventional helical scanning protocol. Here we compare radiation dose and image quality from coronary computed tomography angiography in a single center between an initial period during which helical scanning with electrocardiographically-controlled tube current modulation was used for all patients (n=138) and after adoption of a strategy incorporating sequential scanning whenever appropriate (n=261). Using the sequential-if-appropriate strategy, sequential scanning was employed in 86.2% of patients. Compared to the helical-only strategy, this strategy was associated with a 65.1% dose reduction (mean dose-length product of 305.2 vs. 875.1 and mean effective dose of 14.9 mSv vs. 5.2 mSv, respectively), with no significant change in overall image quality, step artifacts, motion artifacts, or perceived image noise. For the 225 patients undergoing sequential scanning, the dose-length product was 201.9 ± 90.0 mGy·cm, while for patients undergoing helical scanning under either strategy, the dose-length product was 890.9 ± 293.3 mGy·cm (p<0.0001), corresponding to mean effective doses of 3.4 mSv and 15.1 mSv, respectively, a 77.5% reduction. Image quality was significantly greater for the sequential studies, reflecting the poorer image quality in patients undergoing helical scanning in the sequential-if-appropriate strategy. In conclusion, a sequential-if-appropriate diagnostic strategy reduces dose markedly compared to a helical-only strategy, with no significant difference in image quality. PMID:19892048

  17. Low-dose computed tomography image restoration using previous normal-dose scan

    SciTech Connect

    Ma, Jianhua; Huang, Jing; Feng, Qianjin; Zhang, Hua; Lu, Hongbing; Liang, Zhengrong; Chen, Wufan

    2011-10-15

    Purpose: In current computed tomography (CT) examinations, the associated x-ray radiation dose is of a significant concern to patients and operators. A simple and cost-effective means to perform the examinations is to lower the milliampere-seconds (mAs) or kVp parameter (or delivering less x-ray energy to the body) as low as reasonably achievable in data acquisition. However, lowering the mAs parameter will unavoidably increase data noise and the noise would propagate into the CT image if no adequate noise control is applied during image reconstruction. Since a normal-dose high diagnostic CT image scanned previously may be available in some clinical applications, such as CT perfusion imaging and CT angiography (CTA), this paper presents an innovative way to utilize the normal-dose scan as a priori information to induce signal restoration of the current low-dose CT image series. Methods: Unlike conventional local operations on neighboring image voxels, nonlocal means (NLM) algorithm utilizes the redundancy of information across the whole image. This paper adapts the NLM to utilize the redundancy of information in the previous normal-dose scan and further exploits ways to optimize the nonlocal weights for low-dose image restoration in the NLM framework. The resulting algorithm is called the previous normal-dose scan induced nonlocal means (ndiNLM). Because of the optimized nature of nonlocal weights calculation, the ndiNLM algorithm does not depend heavily on image registration between the current low-dose and the previous normal-dose CT scans. Furthermore, the smoothing parameter involved in the ndiNLM algorithm can be adaptively estimated based on the image noise relationship between the current low-dose and the previous normal-dose scanning protocols. Results: Qualitative and quantitative evaluations were carried out on a physical phantom as well as clinical abdominal and brain perfusion CT scans in terms of accuracy and resolution properties. The gain by the use

  18. Personal computers in accelerator control

    NASA Astrophysics Data System (ADS)

    Anderssen, P. S.

    1988-07-01

    The advent of the personal computer has created a popular movement which has also made a strong impact on science and engineering. Flexible software environments combined with good computational performance and large storage capacities are becoming available at steadily decreasing costs. Of equal importance, however, is the quality of the user interface offered on many of these products. Graphics and screen interaction is available in ways that were only possible on specialized systems before. Accelerator engineers were quick to pick up the new technology. The first applications were probably for controllers and data gatherers for beam measurement equipment. Others followed, and today it is conceivable to make personal computer a standard component of an accelerator control system. This paper reviews the experience gained at CERN so far and describes the approach taken in the design of the common control center for the SPS and the future LEP accelerators. The design goal has been to be able to integrate personal computers into the accelerator control system and to build the operator's workplace around it.

  19. Computer-controlled warmup circuit

    NASA Technical Reports Server (NTRS)

    Daeges, J. J.

    1980-01-01

    Filament of high-power radio transmitter is brought to operating temperature automatically. Pushbotton reduces operator's role to one-step command and is compatible with various forms of computer control. Filiament shutdown is initiated by "down" command from operator, failure of cooling systems, or power failure for more than few seconds.

  20. Computational approaches to motor control

    PubMed Central

    Flash, Tamar; Sejnowski, Terrence J

    2010-01-01

    New concepts and computational models that integrate behavioral and neurophysiological observations have addressed several of the most fundamental long-standing problems in motor control. These problems include the selection of particular trajectories among the large number of possibilities, the solution of inverse kinematics and dynamics problems, motor adaptation and the learning of sequential behaviors. PMID:11741014

  1. Galileo Spacecraft Scan Platform Celestial Pointing Cone Control Gain Redesign

    NASA Technical Reports Server (NTRS)

    In, C-H. C.; Hilbert, K. B.

    1994-01-01

    During September and October 1991, pictures of the Gaspra asteroid and neighboring stars were taken by the Galileo Optical Navigation (OPNAV) Team for the purpose of navigation the spacecraft for a successful Gaspra encounter. The star tracks in these pictures showed that the scan platform celestial pointing cone controller performed poorly in compensating for wobble-induced cone offsets.

  2. Scanning Tunneling Microscope Data Acquistion and Control System

    Energy Science and Technology Software Center (ESTSC)

    1995-02-01

    SHOESCAN is a PC based code that acquires and displays data for Scanning Tunneling Microscopes (STM). SHOESCAN interfaces with the STM through external electronic feedback and raster control circuits that are controlled by I/O boards on the PC bus. Data is displayed on a separate color monitor that is interfaced to the PC through an additional frame-grabber board. SHOESCAN can acquire a wide range of surface topographic information as well as surface electronic structure information.

  3. Electric-controlled scanning Luneburg lens based on metamaterials

    NASA Astrophysics Data System (ADS)

    Wang, Min; Huang, Cheng; Pu, Ming-Bo; Hu, Cheng-Gang; Pan, Wen-Bo; Zhao, Ze-Yu; Luo, Xian-Gang

    2013-05-01

    The feasibility of 360∘ scanning Luneburg lens based on electric-controlled metamaterial is analyzed. When the line source is fixed in the center of the lens, the direction of radiated beam can be tuned by adjusting the bias voltages distribution applied to the varactors in each unit cell. By introducing an artificial reflective plane, the gain of the antenna can be further enhanced. The minimal step of scanning angle obtained in simulation is only 7∘, which can be further decreased by increasing the dimension and the number of unit cell used in Luneburg lens.

  4. 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

  5. Computer control by hand gestures

    NASA Astrophysics Data System (ADS)

    Jemel, Intidhar; Ejbali, Ridha; Zaied, Mourad

    2015-12-01

    This work fits into the context of the interpretation of automatic gestures based on computer vision. The aim of our work is to transform a conventional screen in a surface that allows the user to use his hands as pointing devices. These can be summarized in three main steps. Hand detection in a video, monitoring detected hands and conversion paths made by the hands to computer commands. To realize this application, it is necessary to detect the hand to follow. A classification phase is essential, at the control part. For this reason, we resorted to the use of a neuro-fuzzy classifier for classification and a pattern matching method for detection.

  6. Analytical scanning evanescent microwave microscope and control stage

    DOEpatents

    Xiang, Xiao-Dong; Gao, Chen; Duewer, Fred; Yang, Hai Tao; Lu, Yalin

    2013-01-22

    A scanning evanescent microwave microscope (SEMM) that uses near-field evanescent electromagnetic waves to probe sample properties is disclosed. The SEMM is capable of high resolution imaging and quantitative measurements of the electrical properties of the sample. The SEMM has the ability to map dielectric constant, loss tangent, conductivity, electrical impedance, and other electrical parameters of materials. Such properties are then used to provide distance control over a wide range, from to microns to nanometers, over dielectric and conductive samples for a scanned evanescent microwave probe, which enable quantitative non-contact and submicron spatial resolution topographic and electrical impedance profiling of dielectric, nonlinear dielectric and conductive materials. The invention also allows quantitative estimation of microwave impedance using signals obtained by the scanned evanescent microwave probe and quasistatic approximation modeling. The SEMM can be used to measure electrical properties of both dielectric and electrically conducting materials.

  7. Analytical scanning evanescent microwave microscope and control stage

    DOEpatents

    Xiang, Xiao-Dong; Gao, Chen; Duewer, Fred; Yang, Hai Tao; Lu, Yalin

    2009-06-23

    A scanning evanescent microwave microscope (SEMM) that uses near-field evanescent electromagnetic waves to probe sample properties is disclosed. The SEMM is capable of high resolution imaging and quantitative measurements of the electrical properties of the sample. The SEMM has the ability to map dielectric constant, loss tangent, conductivity, electrical impedance, and other electrical parameters of materials. Such properties are then used to provide distance control over a wide range, from to microns to nanometers, over dielectric and conductive samples for a scanned evanescent microwave probe, which enable quantitative non-contact and submicron spatial resolution topographic and electrical impedance profiling of dielectric, nonlinear dielectric and conductive materials. The invention also allows quantitative estimation of microwave impedance using signals obtained by the scanned evanescent microwave probe and quasistatic approximation modeling. The SEMM can be used to measure electrical properties of both dielectric and electrically conducting materials.

  8. From 2-dimensional cephalograms to 3-dimensional computed tomography scans.

    PubMed

    Halazonetis, Demetrios J

    2005-05-01

    Computed tomography is entering the orthodontic specialty as a mainstream diagnostic modality. Radiation exposure and cost have decreased significantly, and the diagnostic value is very high compared with traditional radiographic options. However, 3-dimensional data present new challenges and need a different approach from traditional viewing of static images to make the most of the available possibilities. Advances in computer hardware and software now enable interactive display of the data on personal computers, with the ability to selectively view soft or hard tissues from any angle. Transfer functions are used to apply transparency and color. Cephalometric measurements can be taken by digitizing points in 3-dimensional coordinates. Application of 3-dimensional data is expected to increase significantly soon and might eventually replace many conventional orthodontic records that are in use today. PMID:15877045

  9. Scan Rate: A New Metric for the Analysis of Reading Behaviors in Asynchronous Computer Conferencing Environments

    ERIC Educational Resources Information Center

    Hewitt, Jim; Brett, Clare; Peters, Vanessa

    2007-01-01

    This article introduces a new computer conferencing metric called Scan Rate, which is a measure of students' and instructors' online reading speed. The term "scan" refers to the practice of either skimming through a message at an unusually rapid pace or reading a message partially and then stopping before the end is reached. It is proposed that…

  10. Characterization of Visual Scanning Patterns in Air Traffic Control

    PubMed Central

    McClung, Sarah N.; Kang, Ziho

    2016-01-01

    Characterization of air traffic controllers' (ATCs') visual scanning strategies is a challenging issue due to the dynamic movement of multiple aircraft and increasing complexity of scanpaths (order of eye fixations and saccades) over time. Additionally, terminologies and methods are lacking to accurately characterize the eye tracking data into simplified visual scanning strategies linguistically expressed by ATCs. As an intermediate step to automate the characterization classification process, we (1) defined and developed new concepts to systematically filter complex visual scanpaths into simpler and more manageable forms and (2) developed procedures to map visual scanpaths with linguistic inputs to reduce the human judgement bias during interrater agreement. The developed concepts and procedures were applied to investigating the visual scanpaths of expert ATCs using scenarios with different aircraft congestion levels. Furthermore, oculomotor trends were analyzed to identify the influence of aircraft congestion on scan time and number of comparisons among aircraft. The findings show that (1) the scanpaths filtered at the highest intensity led to more consistent mapping with the ATCs' linguistic inputs, (2) the pattern classification occurrences differed between scenarios, and (3) increasing aircraft congestion caused increased scan times and aircraft pairwise comparisons. The results provide a foundation for better characterizing complex scanpaths in a dynamic task and automating the analysis process. PMID:27239190

  11. Characterization of Visual Scanning Patterns in Air Traffic Control.

    PubMed

    McClung, Sarah N; Kang, Ziho

    2016-01-01

    Characterization of air traffic controllers' (ATCs') visual scanning strategies is a challenging issue due to the dynamic movement of multiple aircraft and increasing complexity of scanpaths (order of eye fixations and saccades) over time. Additionally, terminologies and methods are lacking to accurately characterize the eye tracking data into simplified visual scanning strategies linguistically expressed by ATCs. As an intermediate step to automate the characterization classification process, we (1) defined and developed new concepts to systematically filter complex visual scanpaths into simpler and more manageable forms and (2) developed procedures to map visual scanpaths with linguistic inputs to reduce the human judgement bias during interrater agreement. The developed concepts and procedures were applied to investigating the visual scanpaths of expert ATCs using scenarios with different aircraft congestion levels. Furthermore, oculomotor trends were analyzed to identify the influence of aircraft congestion on scan time and number of comparisons among aircraft. The findings show that (1) the scanpaths filtered at the highest intensity led to more consistent mapping with the ATCs' linguistic inputs, (2) the pattern classification occurrences differed between scenarios, and (3) increasing aircraft congestion caused increased scan times and aircraft pairwise comparisons. The results provide a foundation for better characterizing complex scanpaths in a dynamic task and automating the analysis process. PMID:27239190

  12. Improved controlled atmosphere high temperature scanning probe microscope

    NASA Astrophysics Data System (ADS)

    Hansen, K. V.; Wu, Y.; Jacobsen, T.; Mogensen, M. B.; Theil Kuhn, L.

    2013-07-01

    To locally access electrochemical active surfaces and interfaces in operando at the sub-micron scale at high temperatures in a reactive gas atmosphere is of great importance to understand the basic mechanisms in new functional materials, for instance, for energy technologies, such as solid oxide fuel cells and electrolyzer cells. Here, we report on advanced improvements of our original controlled atmosphere high temperature scanning probe microscope, CAHT-SPM. The new microscope can employ a broad range of the scanning probe techniques including tapping mode, scanning tunneling microscopy, scanning tunneling spectroscopy, conductive atomic force microscopy, and Kelvin probe force microscopy. The temperature of the sample can be as high as 850 °C. Both reducing and oxidizing gases such as oxygen, hydrogen, and nitrogen can be added in the sample chamber and the oxygen partial pressure (pO2) is monitored by an oxygen sensor. We present here some examples of its capabilities demonstrated by high temperature topography with simultaneously ac electrical conductance measurements during atmosphere changes, electrochemical impedance spectroscopy at various temperatures, and measurements of the surface potential. The improved CAHT-SPM, therefore, holds a great potential for local sub-micron analysis of high-temperature and gas induced changes of a wide range of materials.

  13. Early Lung Computed Tomography Scan after Allogeneic Hematopoietic Stem Cell Transplantation.

    PubMed

    Cornetto, Marie Alice; Chevret, Sylvie; Abbes, Sarah; de Margerie-Mellon, Constance; Hussenet, Claire; Sicre de Fontbrune, Flore; Tazi, Abdellatif; Ribaud, Patricia; Bergeron, Anne

    2016-08-01

    A lung computed tomography (CT) scan is essential for diagnosing lung diseases in hematopoietic stem cell transplantation (HSCT) recipients. As a result, lung CT scans are increasingly prescribed in the early phase after allogeneic HSCT, with no assessment of the added value for global patient management. Among 250 patients who underwent allogeneic HSCT in our center over a 2-year period, we evaluated 68 patients who had at least 1 lung CT scan within the first 30 days post-transplantation. The median interval between allogeneic HSCT and lung CT scan was 8.5 days. Patients who underwent an early lung CT scan were more immunocompromised and had a more severe course. Fever was the main indication for the CT scan (78%). The lung CT scan was abnormal in 52 patients, including 17 patients who had an abnormal pre-HSCT CT scan. A therapeutic change was noted in 37 patients (54%) within 24 hours after the lung CT scan. The main changes included the introduction of corticosteroids (n = 23; 62%), especially in patients with a normal CT scan (89%). In univariate models, we found that a normal pretransplantation CT scan (P = .002), the absence of either dyspnea (P = .029) or hypoxemia (P = .015), and a serum C-reactive protein level <10 mg/L (P = .004) were associated with a normal post-HSCT lung CT scan. We found that the association of these variables could predict the normality of early post-HSCT lung CT scans. Pretransplantation lung CT scans are useful for the interpretation of subsequent lung CT scans following allogeneic HSCT, which are frequently abnormal. Early post-HSCT lung CT scans are helpful in patient management, but prescriptions could be more targeted. PMID:27189110

  14. Controller for the Electronically Scanned Thinned Array Radiometer (ESTAR) instrument

    NASA Technical Reports Server (NTRS)

    Zomberg, Brian G.; Chren, William A., Jr.

    1994-01-01

    A prototype controller for the ESTAR (electronically scanned thinned array radiometer) instrument has been designed and tested. It manages the operation of the digital data subsystem (DDS) and its communication with the Small Explorer data system (SEDS). Among the data processing tasks that it coordinates are FEM data acquisition, noise removal, phase alignment and correlation. Its control functions include instrument calibration and testing of two critical subsystems, the output data formatter and Walsh function generator. It is implemented in a Xilinx XC3064PC84-100 field programmable gate array (FPGA) and has a maximum clocking frequency of 10 MHz.

  15. Sinus computed tomography scan and markers of inflammation in vocal cord dysfunction and asthma

    PubMed Central

    Peters, Edward J.; Hatley, Tina K.; Crater, Scott E.; Phillips, C. Douglas; Platts-Mills, Thomas A. E.; Borish, Larry

    2005-01-01

    Background: The inappropriate closure of the vocal cords is characteristic of vocal cord dysfunction (VCD). These patients present with wheezing and frequently receive a misdiagnosis of asthma. Objective: To demonstrate the ability of computed tomography (CT) scored for the presence and extent of sinus disease and markers of inflammation to distinguish patients with VCD from patients with asthma. Methods: Comparisons of 13 patients with VCD were made to 77 patients presenting to the emergency room with acute asthma, 31 non-acute asthmatic patients, and 65 nonasthmatic controls. Evaluation consisted of exhaled nitric oxide gas (eNO), circulating eosinophils, and total serum immunoglobulin (Ig)E, as well as the sinus CT scan. Results: Extensive sinus CT changes were present in 23 of 74 acute asthmatic patients, 5 of 29 non-acute asthmatic patients, and 2 of 59 nonasthmatic controls. In addition, absolute eosinophil counts, eNO, and total IgE were significantly elevated among the asthmatic patients. Sinus symptoms reported by questionnaire did not predict sinus CT findings. Among the patients with VCD, none had extensive sinus disease. They also had normal eNO, low IgE, and normal eosinophil count. Five of the patients presenting to the emergency room who were identified as acute asthmatic were identified with VCD by laryngoscopy and were all characterized by the absence of significant inflammation on their sinus CT scan, low IgE, and normal eosinophil count. Conclusions: Among patients presenting with intermittent or reversible airway obstruction, patients with VCD can be distinguished from asthma by minimum or absence of inflammation in their sinuses as shown by CT scan. Clinical symptom scores are not predictive of presence or extent of sinus disease in most cases. PMID:12669895

  16. CT scan

    MedlinePlus

    CAT scan; Computed axial tomography scan; Computed tomography scan ... Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, et al. eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ...

  17. Control Of Cryogenic Fourier Transform Spectrometer Scanning Mirrors

    NASA Astrophysics Data System (ADS)

    Tripathi, S. S.; Gowrinathan, S.

    1981-12-01

    The Perkin-Elmer Corporation has designed and built a cryogenically cooled Fourier transform spectrometer for spaceborne applications. In operation, the spectrometer requires mirrors moving at constant velocity in both forward and reverse directions. To maintain efficiency and accuracy, the time taken to reverse direction and the vibration induced due to this reversal must be kept within low limits. This paper deals with the control system design for maintaining a constant velocity during forward and reverse scans and for smooth direction reversals. The systems aspects of the problem are described, and time-domain techniques of modern control theory are applied for optimization of turn-around profile. The analysis leads to a suboptimal design easily implemented by using analog-type components. Test results of satisfactory performance are also included.

  18. Semi-automated method to measure pneumonia severity in mice through computed tomography (CT) scan analysis

    NASA Astrophysics Data System (ADS)

    Johri, Ansh; Schimel, Daniel; Noguchi, Audrey; Hsu, Lewis L.

    2010-03-01

    Imaging is a crucial clinical tool for diagnosis and assessment of pneumonia, but quantitative methods are lacking. Micro-computed tomography (micro CT), designed for lab animals, provides opportunities for non-invasive radiographic endpoints for pneumonia studies. HYPOTHESIS: In vivo micro CT scans of mice with early bacterial pneumonia can be scored quantitatively by semiautomated imaging methods, with good reproducibility and correlation with bacterial dose inoculated, pneumonia survival outcome, and radiologists' scores. METHODS: Healthy mice had intratracheal inoculation of E. coli bacteria (n=24) or saline control (n=11). In vivo micro CT scans were performed 24 hours later with microCAT II (Siemens). Two independent radiologists scored the extent of airspace abnormality, on a scale of 0 (normal) to 24 (completely abnormal). Using the Amira 5.2 software (Mercury Computer Systems), a histogram distribution of voxel counts between the Hounsfield range of -510 to 0 was created and analyzed, and a segmentation procedure was devised. RESULTS: A t-test was performed to determine whether there was a significant difference in the mean voxel value of each mouse in the three experimental groups: Saline Survivors, Pneumonia Survivors, and Pneumonia Non-survivors. It was found that the voxel count method was able to statistically tell apart the Saline Survivors from the Pneumonia Survivors, the Saline Survivors from the Pneumonia Non-survivors, but not the Pneumonia Survivors vs. Pneumonia Non-survivors. The segmentation method, however, was successfully able to distinguish the two Pneumonia groups. CONCLUSION: We have pilot-tested an evaluation of early pneumonia in mice using micro CT and a semi-automated method for lung segmentation and scoring system. Statistical analysis indicates that the system is reliable and merits further evaluation.

  19. The advantage of coronal scanning in cerebral computed angiotomography for diagnosis of moyamoya disease

    SciTech Connect

    Asari, S.; Satoh, T.; Sakurai, M.; Yamamoto, Y.; Sadamoto, K.

    1982-12-01

    The advantage of coronal scanning in cerebral computed angiotomography for diagnosis of and screening for moyamoya disease is demonstrated. Characteristic features on the coronal CT scan include (a) attenuation of and difficulty in following the supraclinoid internal carotid arteries and carotid fork and (b) abnormal ''nebula-like'' high-density areas consisting of irregular, tortuous, or patchy vessels arising in the basal cisterns and extending to the basal ganglia.

  20. The Galileo scan platform pointing control system - a modern control theoretic viewpoint.

    NASA Astrophysics Data System (ADS)

    Sevaston, G. E.; Macala, G. A.; Man, G. K.

    In this paper the authors review the current Galileo scan platform pointing control system, and discuss ways in which modern control concepts could contribute toward a better result. Moreover, the authors describe in detail a robust modern control system architecture and the associated design procedures.

  1. Real-time depth monitoring and control of laser machining through scanning beam delivery system

    NASA Astrophysics Data System (ADS)

    Ji, Yang; Grindal, Alexander W.; Webster, Paul J. L.; Fraser, James M.

    2015-04-01

    Scanning optics enable many laser applications in manufacturing because their low inertia allows rapid movement of the process beam across the sample. We describe our method of inline coherent imaging for real-time (up to 230 kHz) micron-scale (7-8 µm axial resolution) tracking and control of laser machining depth through a scanning galvo-telecentric beam delivery system. For 1 cm trench etching in stainless steel, we collect high speed intrapulse and interpulse morphology which is useful for further understanding underlying mechanisms or comparison with numerical models. We also collect overall sweep-to-sweep depth penetration which can be used for feedback depth control. For trench etching in silicon, we show the relationship of etch rate with average power and scan speed by computer processing of depth information without destructive sample post-processing. We also achieve three-dimensional infrared continuous wave (modulated) laser machining of a 3.96 × 3.96 × 0.5 mm3 (length × width × maximum depth) pattern on steel with depth feedback. To the best of our knowledge, this is the first successful demonstration of direct real-time depth monitoring and control of laser machining with scanning optics.

  2. Sector computed tomographic spine scanning in the diagnosis of lumbar nerve root entrapment

    SciTech Connect

    Risius, B.; Modic, M.T.; Hardy, R.W. Jr.; Duchesneau, P.M.; Weinstein, M.A.

    1982-04-01

    The diagnosis of lumbar nerve root entrapment was made by sector computed tomography (CT) scanning in 25 patients whose myelograms were normal at the site of the CT scan abnormalities. Sector CT scanning demonstrates preoperatively which neural foramina are narrow. This information, correlated with the patient's history and physical examination, indicates which foramina should be operated on and prevents unnecessary exploration of normal neutral foramina. CT findings were confirmed surgically in 14 patients. Eleven of these 14 patients had excellent postoperative results and remain pain free.

  3. Computer controlled thermal fatigue test system

    SciTech Connect

    Schmale, D.T.; Jones, W.B.

    1986-01-01

    A servo-controlled hydraulic mechanical test system has been configured to conduct computer-controlled thermal fatigue tests. The system uses induction heating, a digital temperature controller, infrared pyrometry, forced air cooling, and quartz rod extensometry. In addition, a digital computer controls the tests and allows precise data analysis and interpretation.

  4. Computer-Controlled, Motorized Positioning System

    NASA Technical Reports Server (NTRS)

    Vargas-Aburto, Carlos; Liff, Dale R.

    1994-01-01

    Computer-controlled, motorized positioning system developed for use in robotic manipulation of samples in custom-built secondary-ion mass spectrometry (SIMS) system. Positions sample repeatably and accurately, even during analysis in three linear orthogonal coordinates and one angular coordinate under manual local control, or microprocessor-based local control or remote control by computer via general-purpose interface bus (GPIB).

  5. Computers and quality control in nuclear medicine.

    PubMed

    Brookeman, V A

    1978-04-01

    The general topic of computers and nuclear medicine quality control may be approached from two main areas; controlling the quality of computerized studies, and computer applications in general nuclear medicine quality control. Overlap occurs when quality control of computer studies is performed by the computer itself. The uses of computers in record-keeping and in quality control of imaging instrumentation and in vitro studies, including radioimmunoassay, are discussed in this review. Aspects of quality control for computerized clinical cardiovascular, cerebral, and renal studies and emission computed tomography are reviewed, including consideration of difficulties and inaccuracies involved in the studies. Any automatic computer analysis program should incorporate adequate checks and error detection protocols and should illustrate results for verification. Current routine quality control procedures using the computer unfortunately are few. Quality control criteria are needed for camera/computer systems in high count rate clinical applications, and increasing emphasis should be aimed at quality control of those computerized dynamic and function studies in current clinical use. The computer has a valuable potential for nuclear medicine quality control. In vitro and computerized in vivo studies can be analyzed by readily available statistical programs, and variances can be monitored continuously. Computers can calibrate and monitor instrument performance regularly, and can handle managerial and clerical duties such as bookkeeping. PMID:684439

  6. Progressive dyspnea associated with a crazy-paving appearance on a chest computed tomography scan.

    PubMed

    Maimon, Nimrod; Paul, Narinder; Downey, Gregory P

    2006-01-01

    A 'crazy-paving' appearance of the lungs on computed tomography scanning of the chest was first described nearly 20 years ago in patients with pulmonary alveolar proteinosis, and was thought to be characteristic of this condition. However, this pattern has subsequently been reported in a variety of pulmonary diseases and is now considered to be nonspecific. The present report describes a case of a 74-year-old man in whom congestive heart failure presented with a crazy-paving appearance of the lungs on a chest computed tomography scan. This uncommon association illustrates the importance of the correlation of clinical and radiographic information. PMID:16896429

  7. Review of P-scan computer-based ultrasonic inservice inspection system. Supplement 1

    SciTech Connect

    Harris, R.V. Jr.; Angel, L.J.

    1995-12-01

    This Supplement reviews the P-scan system, a computer-based ultrasonic system used for inservice inspection of piping and other components in nuclear power plants. The Supplement was prepared using the methodology described in detail in Appendix A of NUREG/CR-5985, and is based on one month of using the system in a laboratory. This Supplement describes and characterizes: computer system, ultrasonic components, and mechanical components; scanning, detection, digitizing, imaging, data interpretation, operator interaction, data handling, and record-keeping. It includes a general description, a review checklist, and detailed results of all tests performed.

  8. COMPUTER CONTROL OF BEHAVIORAL EXPERIMENTS.

    ERIC Educational Resources Information Center

    SIEGEL, LOUIS

    THE LINC COMPUTER PROVIDES A PARTICULAR SCHEDULE OF REINFORCEMENT FOR BEHAVIORAL EXPERIMENTS BY EXECUTING A SEQUENCE OF COMPUTER OPERATIONS IN CONJUNCTION WITH A SPECIALLY DESIGNED INTERFACE. THE INTERFACE IS THE MEANS OF COMMUNICATION BETWEEN THE EXPERIMENTAL CHAMBER AND THE COMPUTER. THE PROGRAM AND INTERFACE OF AN EXPERIMENT INVOLVING A PIGEON…

  9. Control and Power in Educational Computing.

    ERIC Educational Resources Information Center

    Kahn, Peter H., Jr.; Friedman, Batya

    Educational computing based on the primacy of human agency is explored, considering ways in which power can be apportioned and exercised in order to enhance educational computing. Ideas about power and control are situated epistemologically. A first consideration is educating for human control of computer technology. Research suggests that…

  10. Computer Aided Control System Design (CACSD)

    NASA Technical Reports Server (NTRS)

    Stoner, Frank T.

    1993-01-01

    The design of modern aerospace systems relies on the efficient utilization of computational resources and the availability of computational tools to provide accurate system modeling. This research focuses on the development of a computer aided control system design application which provides a full range of stability analysis and control design capabilities for aerospace vehicles.

  11. Computer Instructional Aids for Undergraduate Control Education.

    ERIC Educational Resources Information Center

    Volz, Richard A.; And Others

    Engineering is coming to rely more and more heavily upon the computer for computations, analyses, and graphic displays which aid the design process. A general purpose simulation system, the Time-shared Automatic Control Laboratory (TACL), and a set of computer-aided design programs, Control Oriented Interactive Graphic Analysis and Design…

  12. a Pc-Controlled Ultrafast Scanning Electrochemical Detector for High Performance Liquid Chromatography.

    NASA Astrophysics Data System (ADS)

    Rhodes, Derek Frank

    This research focuses on the design, implementation and evaluation of an ultra-fast scanning Electrochemical Detector (ECD) for High Performance Liquid Chromatography, (HPLC). The scanning detector employs a microelectrode array as the working electrode. The electrode array has been designed to fit directly into a commercially available ECD cell. Microelectrodes allow very rapid changes in potential while maintaining low background currents. Rapidly scanning the potential up to 10 volts per second yields time resolved current-voltage profiles of components as they elute from a chromatographic column. Coeluting peaks in the time domain are then resolved in the potential domain by taking the differential of the electrochemical profile. Several microelectrode arrays for various electrochemical detection techniques were evaluated using gold and carbon electrodes of radius 25mum, 6.5mu m and 3mum with solutions of ferrocene and catecholamines. The detector interface, software and electronics were engineered to interface with an IBM AT or compatible computer with 640 K of memory, a hard disk and a 20 MHz analog-to-digital digital-to-analog board. The rapid potential changes and the resulting cell current were controlled and monitored using fast executing assembler routines. Computer control of the ECD system made the application of a variety of amperometric techniques possible. Extensive data reduction procedures such as signal sorting from three dimensional data (E-i-t), and data averaging and smoothing were also developed. The research also explored the effect of flow rate and solution resistance on the electrochemical cell current.

  13. To assess vascular calcification in the patients of hypoparathyroidism using multidetector computed tomography scan

    PubMed Central

    Agarwal, Pooja; Prakash, Mahesh; Singhal, Manphool; Bhadada, Sanjay Kumar; Gupta, Yashdeep; Khandelwal, Niranjan

    2015-01-01

    Background: Our pilot data showed an increased intima media thickness in the patients with sporadic idiopathic hypoparathyroidism (SIH). Alteration in homeostasis of calcium, phosphate, and parathyroid hormone (PTH) may predispose to increase the risk of cardiovascular morbidity and mortality. The data on objective assessment of this increased risk is however lacking. Objective: To assess the effect of altered calcium, phosphate, and PTH homeostasis in the patients with SIH on coronary calcium score (a marker of increase vascular risk) by multidetector computed tomography scan (MDCT). Methods: In this case-control study, we measured coronary CT calcium score in 30 patients of SIH and compared with 40 age and sex matched healthy subjects. Correlation of coronary calcium score with biochemical parameters was evaluated. Results: Three of the 30 cases (10%) with SIH were found to have coronary artery calcification (CAC) of varying degree, whereas none of the control showed CAC (P = 0.07). The patients with CAC had significantly lower serum calcium levels (albumin corrected), as compared to the patients without CAC. Inverse correlation of CAC was found with serum calcium levels. No correlation was found with other biochemical parameters. Conclusion: The vascular risk is increased in the patients with SIH as assessed by coronary calcium score measured by MDCT. Low serum calcium levels might be a predisposing factor for this increased risk. PMID:26693429

  14. Complications in CT-guided Procedures: Do We Really Need Postinterventional CT Control Scans?

    SciTech Connect

    Nattenmüller, Johanna Filsinger, Matthias Bryant, Mark Stiller, Wolfram Radeleff, Boris Grenacher, Lars Kauczor, Hans-Ullrich Hosch, Waldemar

    2013-06-19

    PurposeThe aim of this study is twofold: to determine the complication rate in computed tomography (CT)-guided biopsies and drainages, and to evaluate the value of postinterventional CT control scans.MethodsRetrospective analysis of 1,067 CT-guided diagnostic biopsies (n = 476) and therapeutic drainages (n = 591) in thoracic (n = 37), abdominal (n = 866), and musculoskeletal (ms) (n = 164) locations. Severity of any complication was categorized as minor or major. To assess the need for postinterventional CT control scans, it was determined whether complications were detected clinically, on peri-procedural scans or on postinterventional scans only.ResultsThe complication rate was 2.5 % in all procedures (n = 27), 4.4 % in diagnostic punctures, and 1.0 % in drainages; 13.5 % in thoracic, 2.0 % in abdominal, and 3.0 % in musculoskeletal procedures. There was only 1 major complication (0.1 %). Pneumothorax (n = 14) was most frequent, followed by bleeding (n = 9), paresthesia (n = 2), material damage (n = 1), and bone fissure (n = 1). Postinterventional control acquisitions were performed in 65.7 % (701 of 1,067). Six complications were solely detectable in postinterventional control acquisitions (3 retroperitoneal bleeds, 3 pneumothoraces); all other complications were clinically detectable (n = 4) and/or visible in peri-interventional controls (n = 21).ConclusionComplications in CT-guided interventions are rare. Of these, thoracic interventions had the highest rate, while pneumothoraces and bleeding were most frequent. Most complications can be detected clinically or peri-interventionally. To reduce the radiation dose, postinterventional CT controls should not be performed routinely and should be restricted to complicated or retroperitoneal interventions only.

  15. An adaptable head retention and alignment device for computed tomography scanning of Macaca mulatta.

    PubMed

    Bidez, M W; Mcloughlin, S W; Chen, Y; Lakshminarayanan, A V; Jeffcoat, M K

    1994-10-01

    An adaptable retention device has been developed for the purpose of holding and aligning the head of a sedated primate subject during computed tomography (CT) scan procedures. The device is used to obtain a close reproduction of CT scan studies at a time before and after dental implant placement in the mandibles of nine subjects. Geometric and material properties are extracted from these studies for the purpose of developing finite elements computer models. The device is constructed of low-density acrylic and consists of a horizontal base to which lateral supports are affixed. The device is placed on the CT table and axially aligned with the scan beam. Repeatable, calibrated CT studies of primate implant subjects were possible using the head holding device. PMID:7962014

  16. Micro computed tomography (CT) scanned anatomical gateway to insect pest bioinformatics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An international collaboration to establish an interactive Digital Video Library for a Systems Biology Approach to study the Asian citrus Psyllid and psyllid genomics/proteomics interactions is demonstrated. Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pic...

  17. Sparse-view computed laminography with a spherical sinusoidal scan for nondestructive testing.

    PubMed

    Abbas, Sajid; Park, Miran; Min, Jonghwan; Kim, Ho Kyung; Cho, Seungryong

    2014-07-28

    X-ray computed laminography is widely used in nondestructive testing of relatively flat objects using an oblique scanning configuration for data acquisition. In this work, a new scanning scheme is proposed in conjunction with the compressive-sensing-based image reconstruction for reducing imaging radiation dose and scanning time. We performed a numerical study comparing image qualities acquired by various scanning configurations that are practically implementable: single-arc, double-arc, oblique, and spherical-sinusoidal trajectories. A compressive-sensing-inspired total-variation (TV) minimization algorithm was used to reconstruct the images from the data acquired at only 40 projection views in those trajectories. It was successfully demonstrated that the proposed scanning scheme outperforms the others in terms of image contrast and spatial resolution, although the oblique scanning scheme showed a comparable resolution property. We believe that the proposed scanning method may provide a solution to fast and low-dose nondestructive testing of radiation-sensitive and highly integrated devices such as multilayer microelectronic circuit boards. PMID:25089394

  18. The Galileo scan platform pointing control system - A modern control theoretic viewpoint

    NASA Astrophysics Data System (ADS)

    Sevaston, G. E.; Macala, G. A.; Man, G. K.

    The current Galileo scan platform pointing control system (SPPCS) is described, and ways in which modern control concepts could serve to enhance it are considered. Of particular interest are: the multi-variable design model and overall control system architecture, command input filtering, feedback compensator and command input design, stability robustness constraint for both continuous time control systems and for sampled data control systems, and digital implementation of the control system. The proposed approach leads to the design of a system that is similar to current Galileo SPPCS configuration, but promises to be more systematic.

  19. Computers Control the Instruments of Science.

    ERIC Educational Resources Information Center

    House, James E.

    1982-01-01

    Discusses the role and use of microcomputers in scientific research, from monitoring instruments to controlling experimental processes. Included are descriptions of a computer-controlled protein sequencer and gene synthesizer, and microcomputer uses in medicine, physiology, biochemistry, and geology. (JN)

  20. A History of Computer Numerical Control.

    ERIC Educational Resources Information Center

    Haggen, Gilbert L.

    Computer numerical control (CNC) has evolved from the first significant counting method--the abacus. Babbage had perhaps the greatest impact on the development of modern day computers with his analytical engine. Hollerith's functioning machine with punched cards was used in tabulating the 1890 U.S. Census. In order for computers to become a…

  1. Detection model modeling and application for batch scans of cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Huang, Kuidong; Zhang, Dinghua; Li, Mingjun; Wang, Kuyu

    2009-07-01

    Aiming at the artifact corrections for batch scans in Cone-Beam Computed Tomography (CBCT) system, the concept of detection model is proposed. Expressing the prior knowledge of CT system and scanned object properties by the detection model, the rapid artifact corrections are achieved based on the object knowledge, which can save the machine consumption, enhance the detection efficiency and improve the correction effect. Based on the Digital Radiography (DR) imaging conditions remained basically unchanged in the batch scans, the modeling method of detection model is established by getting the relevant information through the detected scanning for one of a batch of parts. Finally, the processing flow of CBCT scans and artifact corrections of a batch of parts based on the detection model is given, and some key problems in the flow are discussed to improve the practical operability of the method. The experimental result shows that the modeling method of detection model is feasible, and the rapid CBCT scans and effective artifact corrections can be realized based on the obtained detection model.

  2. A Large Scale Computer Terminal Output Controller.

    ERIC Educational Resources Information Center

    Tucker, Paul Thomas

    This paper describes the design and implementation of a large scale computer terminal output controller which supervises the transfer of information from a Control Data 6400 Computer to a PLATO IV data network. It discusses the cost considerations leading to the selection of educational television channels rather than telephone lines for…

  3. THE INTEGRATED USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY, AND VIRTUAL REALITY TO PREDICT THE CHEMICAL REACTIVITY OF ENVIRONMENTAL SURFACES

    EPA Science Inventory

    In the last decade three new techniques scanning probe microscopy (SPM), virtual reality (YR) and computational chemistry ave emerged with the combined capability of a priori predicting the chemically reactivity of environmental surfaces. Computational chemistry provides the cap...

  4. Performance assessment of a new dynamic scan mode for perfusion computed tomography using a biological phantom

    NASA Astrophysics Data System (ADS)

    Haberland, U.; Klotz, E.,; Abolmaali, N.

    2010-04-01

    Perfusion computed tomography is increasingly being used for stroke and tumor assessment. Using continuous periodic table movement the spatial coverage can be increased beyond the detector width with a new adaptive spiral scanning technique (A4DS). The purpose of this study was to compare perfusion values acquired with the A4DS technique with results from standard dynamic scans at different temporal sampling rates. A biological perfusion phantom (preserved porcine kidney) was scanned with both techniques. In standard mode three scans were performed at adjacent overlapping positions (detector width 38.4 mm) covering the whole phantom. Data were reconstructed with temporal resolutions of 0.5, 1 and 1.5 s. The A4DS scan was performed with a cycle time of 1.5 s and scan ranges of 100 and 148 mm respectively. The phantom was not repositioned between scans in order to assure that identical image slices showed identical phantom slices. Tissue flow was calculated with a deconvolution type algorithm. Regions of interest were drawn in strongly and moderately enhancing areas and around the whole cortex in three slices in the upper, central and lower portion of the phantom. In the flow range of 40 to 100 ml/100ml/min values did not differ by more than 5 ml/100ml/min between any of the scan protocols used. The correlation between the continuous table movement modes and the 0.5 s standard mode was excellent (r2>0.98) indicating that the new mode is well suited for perfusion measurements and allows increasing the coverage by almost a factor of four.

  5. Proceedings of the 1st Space Plasma Computer Analysis Network (SCAN) Workshop. [space plasma computer networks

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Waite, J. H.; Johnson, J. F. E.; Doupnik, J. R.; Heelis, R. A.

    1983-01-01

    The purpose of the workshop was to identify specific cooperative scientific study topics within the discipline of Ionosphere Magnetosphere Coupling processes and to develop methods and procedures to accomplish this cooperative research using SCAN facilities. Cooperative scientific research was initiated in the areas of polar cusp composition, O+ polar outflow, and magnetospheric boundary morphology studies and an approach using a common metafile structure was adopted to facilitate the exchange of data and plots between the various workshop participants. The advantages of in person versus remote workshops were discussed also.

  6. Computer control for remote wind turbine operation

    SciTech Connect

    Manwell, J.F.; Rogers, A.L.; Abdulwahid, U.; Driscoll, J.

    1997-12-31

    Light weight wind turbines located in harsh, remote sites require particularly capable controllers. Based on extensive operation of the original ESI-807 moved to such a location, a much more sophisticated controller than the original one has been developed. This paper describes the design, development and testing of that new controller. The complete control and monitoring system consists of sensor and control inputs, the control computer, control outputs, and additional equipment. The control code was written in Microsoft Visual Basic on a PC type computer. The control code monitors potential faults and allows the turbine to operate in one of eight states: off, start, run, freewheel, low wind shut down, normal wind shutdown, emergency shutdown, and blade parking. The controller also incorporates two {open_quotes}virtual wind turbines,{close_quotes} including a dynamic model of the machine, for code testing. The controller can handle numerous situations for which the original controller was unequipped.

  7. Heart CT scan

    MedlinePlus

    CAT scan - heart; Computed axial tomography scan - heart; Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agaston score; Coronary calcium scan

  8. Micrometric precision of prosthetic dental crowns obtained by optical scanning and computer-aided designing/computer-aided manufacturing system

    NASA Astrophysics Data System (ADS)

    das Neves, Flávio Domingues; de Almeida Prado Naves Carneiro, Thiago; do Prado, Célio Jesus; Prudente, Marcel Santana; Zancopé, Karla; Davi, Letícia Resende; Mendonça, Gustavo; Soares, Carlos José

    2014-08-01

    The current study evaluated prosthetic dental crowns obtained by optical scanning and a computer-aided designing/computer-aided manufacturing system using micro-computed tomography to compare the marginal fit. The virtual models were obtained with four different scanning surfaces: typodont (T), regular impressions (RI), master casts (MC), and powdered master casts (PMC). Five virtual models were obtained for each group. For each model, a crown was designed on the software and milled from feldspathic ceramic blocks. Micro-CT images were obtained for marginal gap measurements and the data were statistically analyzed by one-way analysis of variance followed by Tukey's test. The mean vertical misfit was T=62.6±65.2 μm; MC=60.4±38.4 μm; PMC=58.1±38.0 μm, and RI=89.8±62.8 μm. Considering a percentage of vertical marginal gap of up to 75 μm, the results were T=71.5%, RI=49.2%, MC=69.6%, and PMC=71.2%. The percentages of horizontal overextension were T=8.5%, RI=0%, MC=0.8%, and PMC=3.8%. Based on the results, virtual model acquisition by scanning the typodont (simulated mouth) or MC, with or without powder, showed acceptable values for the marginal gap. The higher result of marginal gap of the RI group suggests that it is preferable to scan this directly from the mouth or from MC.

  9. Motion artifacts in CT scans: a study by computer simulation and mechanical phantom

    NASA Astrophysics Data System (ADS)

    Tien, Der-Chi; Lung, Jen-Kuang; Liao, Chih-Yu; Yong, Tung-Che; Hsu, Chung-Hsien; Liao, Chih-Chiang; Wu, Ren-Hong; Tseng, Kuo-Hsiung; Tsung, Tsing-Tshih

    2008-11-01

    Computed tomography (CT) is one of the most important tools in the diagnosis of thoracic tumors. However, during the scanning process, respiratory motion causes changes in the position and shape of the tumor, creating motion artifacts in the CT scan. This can lead to misdiagnosis of the size and position of the tumor, and can affect the effectiveness of treatment. This study develops a computer model of the movement of the thorax, and simulates the movement of a lung tumor caused by breathing during a CT scan. We show that adjusting the CT slice thickness is sufficient to determine the center of displacement and maximum displacement of a tumor during normal breathing. This model can be applied in the clinical diagnostic use of CT equipment. It will assist in finding the position of lung tumors from motion artifacts in CT scans. The target margin for treatment can thus be defined more accurately, so that appropriate doses of radiation can be applied to the target area, and irradiation of healthy tissue avoided.

  10. Open Source Scanning Probe Microscopy Control Software Package Gxsm

    SciTech Connect

    Zahl P.; Wagner, T.; Moller, R.; Klust, A.

    2009-08-10

    Gxsm is a full featured and modern scanning probe microscopy (SPM) software. It can be used for powerful multidimensional image/data processing, analysis, and visualization. Connected toan instrument, it is operating many different avors of SPM, e.g., scanning tunneling microscopy(STM) and atomic force microscopy (AFM) or in general two-dimensional multi channel data acquisition instruments. The Gxsm core can handle different data types, e.g., integer and oating point numbers. An easily extendable plug-in architecture provides many image analysis and manipulation functions. A digital signal processor (DSP) subsystem runs the feedback loop, generates the scanning signals and acquires the data during SPM measurements. The programmable Gxsm vector probe engine performs virtually any thinkable spectroscopy and manipulation task, such as scanning tunneling spectroscopy (STS) or tip formation. The Gxsm software is released under the GNU general public license (GPL) and can be obtained via the Internet.

  11. Detection of coronary calcifications from computed tomography scans for automated risk assessment of coronary artery disease

    SciTech Connect

    Isgum, Ivana; Rutten, Annemarieke; Prokop, Mathias; Ginneken, Bram van

    2007-04-15

    A fully automated method for coronary calcification detection from non-contrast-enhanced, ECG-gated multi-slice computed tomography (CT) data is presented. Candidates for coronary calcifications are extracted by thresholding and component labeling. These candidates include coronary calcifications, calcifications in the aorta and in the heart, and other high-density structures such as noise and bone. A dedicated set of 64 features is calculated for each candidate object. They characterize the object's spatial position relative to the heart and the aorta, for which an automatic segmentation scheme was developed, its size and shape, and its appearance, which is described by a set of approximated Gaussian derivatives for which an efficient computational scheme is presented. Three classification strategies were designed. The first one tested direct classification without feature selection. The second approach also utilized direct classification, but with feature selection. Finally, the third scheme employed two-stage classification. In a computationally inexpensive first stage, the most easily recognizable false positives were discarded. The second stage discriminated between more difficult to separate coronary calcium and other candidates. Performance of linear, quadratic, nearest neighbor, and support vector machine classifiers was compared. The method was tested on 76 scans containing 275 calcifications in the coronary arteries and 335 calcifications in the heart and aorta. The best performance was obtained employing a two-stage classification system with a k-nearest neighbor (k-NN) classifier and a feature selection scheme. The method detected 73.8% of coronary calcifications at the expense of on average 0.1 false positives per scan. A calcium score was computed for each scan and subjects were assigned one of four risk categories based on this score. The method assigned the correct risk category to 93.4% of all scans.

  12. Computational Control Workstation: Users' perspectives

    NASA Technical Reports Server (NTRS)

    Roithmayr, Carlos M.; Straube, Timothy M.; Tave, Jeffrey S.

    1993-01-01

    A Workstation has been designed and constructed for rapidly simulating motions of rigid and elastic multibody systems. We examine the Workstation from the point of view of analysts who use the machine in an industrial setting. Two aspects of the device distinguish it from other simulation programs. First, one uses a series of windows and menus on a computer terminal, together with a keyboard and mouse, to provide a mathematical and geometrical description of the system under consideration. The second hallmark is a facility for animating simulation results. An assessment of the amount of effort required to numerically describe a system to the Workstation is made by comparing the process to that used with other multibody software. The apparatus for displaying results as a motion picture is critiqued as well. In an effort to establish confidence in the algorithms that derive, encode, and solve equations of motion, simulation results from the Workstation are compared to answers obtained with other multibody programs. Our study includes measurements of computational speed.

  13. Parallel computations and control of adaptive structures

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Alvin, Kenneth F.; Belvin, W. Keith; Chong, K. P. (Editor); Liu, S. C. (Editor); Li, J. C. (Editor)

    1991-01-01

    The equations of motion for structures with adaptive elements for vibration control are presented for parallel computations to be used as a software package for real-time control of flexible space structures. A brief introduction of the state-of-the-art parallel computational capability is also presented. Time marching strategies are developed for an effective use of massive parallel mapping, partitioning, and the necessary arithmetic operations. An example is offered for the simulation of control-structure interaction on a parallel computer and the impact of the approach presented for applications in other disciplines than aerospace industry is assessed.

  14. Refurbishment program of HANARO control computer system

    SciTech Connect

    Kim, H. K.; Choe, Y. S.; Lee, M. W.; Doo, S. K.; Jung, H. S.

    2012-07-01

    HANARO, an open-tank-in-pool type research reactor with 30 MW thermal power, achieved its first criticality in 1995. The programmable controller system MLC (Multi Loop Controller) manufactured by MOORE has been used to control and regulate HANARO since 1995. We made a plan to replace the control computer because the system supplier no longer provided technical support and thus no spare parts were available. Aged and obsolete equipment and the shortage of spare parts supply could have caused great problems. The first consideration for a replacement of the control computer dates back to 2007. The supplier did not produce the components of MLC so that this system would no longer be guaranteed. We established the upgrade and refurbishment program in 2009 so as to keep HANARO up to date in terms of safety. We designed the new control computer system that would replace MLC. The new computer system is HCCS (HANARO Control Computer System). The refurbishing activity is in progress and will finish in 2013. The goal of the refurbishment program is a functional replacement of the reactor control system in consideration of suitable interfaces, compliance with no special outage for installation and commissioning, and no change of the well-proved operation philosophy. HCCS is a DCS (Discrete Control System) using PLC manufactured by RTP. To enhance the reliability, we adapt a triple processor system, double I/O system and hot swapping function. This paper describes the refurbishment program of the HANARO control system including the design requirements of HCCS. (authors)

  15. Development of a phase-controlled constant-distance scanning electrochemical microscope.

    PubMed

    Cougnon, Charles; Bauer-Espindola, Klaus; Fabre, Dimitri S; Mauzeroll, Janine

    2009-05-01

    The present shear-force constant-distance scanning electrochemical microscope regulates tip-to-substrate distance using a phase-controlled feedback mechanism that is more sensitive than the amplitude-controlled constant-distance scanning electrochemical microscopes. Phase control responds faster to frequency perturbation and presents enhance sensitivity during distance curves under constant-distance mode. PMID:19326905

  16. A PC-controlled ultrafast scanning electrochemical detector for high-performance liquid chromatography

    SciTech Connect

    Rhodes, D.F.

    1989-01-01

    This research focuses on the design, implementation and evaluation of an ultra-fast scanning Electrochemical Detector (ECD) for High Performance Liquid Chromatography, (HPLC). The scanning detector employs a microelectrode array as the working electrode. The electrode array has been designed to fit directly into a commercially available ECD cell. Microelectrodes allow very rapid changes in potential while maintaining low background currents. Rapidly scanning the potential up to 10 volts per second yields time resolved current-voltage profiles of components as they elute from a chromatographic column. Coeluting peaks in the time domain are then resolved in the potential domain by taking the differential of the electrochemical profile. Several microelectrode arrays for various electrochemical detection techniques were evaluated using gold and carbon electrodes of radius 25{mu}m, 6.5{mu}m and 3{mu}m with solutions of ferrocene and catecholamines. The detector interface, software and electronics were engineered to interface with an IBM AT or compatible computer with 640 K of memory, a hard disk and a 20 MHz analog-to-digital digital-to-analog board. The rapid potential changes and the resulting cell current were controlled and monitored using fast executing assembler routines. Computer control of the ECD system made the application of a variety of amperometric techniques possible. Extensive data reduction procedures such as signal sorting from three dimensional data (E-i-t), and data averaging and smoothing were also developed. The research also explored the effect of flow rate and solution resistance on the electrochemical cell current.

  17. Using computed tomography scans to develop an ex-vivo gastric model

    PubMed Central

    Henry, Jerome A; O’Sullivan, Gerard; Pandit, Abhay S

    2007-01-01

    The objective of this research was to use abdominal computed tomography (CT) scans to non-invasively quantify anthropometrical data of the human stomach and to concomitantly create an anatomically correct and distensible ex-vivo gastric model. Thirty-three abdominal CT scans of human subjects were obtained and were imported into reconstruction software to generate 3D models of the stomachs. Anthropometrical data such as gastric wall thickness, gastric surface area and gastric volume were subsequently quantified. A representative 3D computer model was exported into a selective laser sintering (SLS) rapid prototyping machine to create an anatomically correct solid gastric model. Subsequently, a replica wax template of the SLS model was created. A negative mould was offset around the wax template such that the offset distance was equivalent to that of the gastric wall thickness. A silicone with similar mechanical properties to the human stomach was poured into the offset. The lost wax manufacturing technique was employed to create a hollow distensible stomach model. 3D computer gastric models were generated from the CT scans. A hollow distensible silicone ex-vivo gastric model with similar compliance to that of the human stomach was created. The anthropometrical data indicated that there is no significant relationship between BMI and gastric surface area or gastric volume. There were inter- and intra-group differences between groups with respect to gastric wall thickness. This study demonstrates that abdominal CT scans can be used to both non-invasively determine gastric anthropometrical data as well as create realistic ex-vivo stomach models. PMID:17457968

  18. The Diminishing Role of Pelvic Stability Evaluation in the Era of Computed Tomographic Scanning

    PubMed Central

    Fu, Chih-Yuan; Teng, Lan-Hsuan; Liao, Chien-Hung; Hsu, Yu-Pao; Wang, Shang-Yu; Kuo, Ling-Wei; Yuan, Kuo-Ching

    2016-01-01

    Abstract Pelvic fractures can result in life-threatening hemorrhages or other associated injuries. Therefore, computed tomography (CT) scanning plays a key role in the management of pelvic fracture patients. However, CT scanning is utilized as an adjunct in secondary survey according to traditional Advanced Trauma Life Support (ATLS) guidelines, whereas pelvic x-ray is used as a primary tool to evaluate pelvic stability and the necessity of further CT scanning. In the current study, we attempted to evaluate the role of CT scanning in the era of advanced technology. The significance of pelvic stability was also analyzed. From January 2012 to December 2014, the trauma registry and medical records of pelvic fracture patients were retrospectively reviewed. A 64-slice multidetector CT scanner was used in our emergency department as a standard diagnostic tool for evaluating trauma patients. Pelvic x-ray was used as a primary tool for screening pelvic fractures, and pelvic stability was evaluated accordingly. CT scans were performed in patients with unstable pelvic fractures, suspected associated intra-abdominal injuries (IAIs), or other conditions based on the physicians’ clinical judgment. The clinical features of patients with stable and unstable pelvic fractures were compared. The patients with stable pelvic fractures were analyzed to determine the characteristics associated with retroperitoneal hemorrhage (RH) or IAIs. Patients with stable pelvic fractures were also compared based on whether they underwent a CT scan. A total of 716 patients were enrolled in this study. There were 533 (74.4%) patients with stable pelvic fractures. Of these patients, there were 66 (12.4%) and 50 (9.4%) patients with associated RH and IAI, respectively. There were no significant differences between the patients with associated RH based on their primary evaluation (vital signs, volume of blood transfusion, and hemoglobin level). Similarly, the demographics and the primary evaluation

  19. Computer controlled vent and pressurization system

    NASA Technical Reports Server (NTRS)

    Cieslewicz, E. J.

    1975-01-01

    The Centaur space launch vehicle airborne computer, which was primarily used to perform guidance, navigation, and sequencing tasks, was further used to monitor and control inflight pressurization and venting of the cryogenic propellant tanks. Computer software flexibility also provided a failure detection and correction capability necessary to adopt and operate redundant hardware techniques and enhance the overall vehicle reliability.

  20. Fast scan control for deflection type mass spectrometers

    NASA Technical Reports Server (NTRS)

    Yeager, P. R.; Gaetano, G.; Hughes, D. B. (Inventor)

    1974-01-01

    A high speed scan device is reported that allows most any scanning sector mass spectrometer to measure preselected gases at a very high sampling rate. The device generates a rapidly changing staircase output which is applied to the accelerator of the spectrometer and it also generates defocusing pulses that are applied to one of the deflecting plates of the spectrometer which when shorted to ground deflects the ion beam away from the collector. A defocusing pulse occurs each time there is a change in the staircase output.

  1. Cranial computed tomography scan findings in head trauma patients in Enugu, Nigeria

    PubMed Central

    Ohaegbulam, Samuel C.; Mezue, Wilfred C.; Ndubuisi, Chika A.; Erechukwu, Uwadiegwu A.; Ani, Chinenye O.

    2011-01-01

    Background: The choice of radiological investigations in head trauma in Africa is influenced by factors such as cost. Some patients who require computed tomography (CT) scan elsewhere are either managed blindly or do not present for it at the appropriate time. This paper evaluates the CT scan findings as they are obtained in cases of head trauma in a region of Nigeria. Methods: Prospectively recorded data of all head injury patients who presented for CT scan between January 2009 and April 2010 at Memfys Hospital for Neurosurgery (MHN), Enugu, Nigeria, were analyzed. Mobile CereTom 8-Slice CT was used in all cases. New and follow-up cases were included. Results: There were 204 CT scans for head trauma (171 new, 33 follow-up), accounting for about 34% of all head CT scans performed with this unit. The male to female ratio was 3.5:1. About 33.9% of the patients were in the third and fourth decades of life. In 19.9% cases, CT was unremarkable, while 80.1% cases had abnormal CT findings. The CT diagnosis was not in keeping with the indication of head trauma in 7%, and 13% had more than one finding. The most common CT findings were: subdural hematoma 30%, cerebral contusions and edema 30.7%, skull fractures 23.4% and extradural hematoma 8.0%. About 64% of the CT findings required surgical interventions. The overall mortality was 11.1%, but amongst the 137 patients who had abnormal CT findings, it was 13.9%. Conclusion: The high yield and diversity of CT scan findings in head trauma patients support the indication for the appropriate use of CT in diagnosis and management of head trauma even in developing countries. PMID:22276236

  2. Controlling Laboratory Processes From A Personal Computer

    NASA Technical Reports Server (NTRS)

    Will, H.; Mackin, M. A.

    1991-01-01

    Computer program provides natural-language process control from IBM PC or compatible computer. Sets up process-control system that either runs without operator or run by workers who have limited programming skills. Includes three smaller programs. Two of them, written in FORTRAN 77, record data and control research processes. Third program, written in Pascal, generates FORTRAN subroutines used by other two programs to identify user commands with device-driving routines written by user. Also includes set of input data allowing user to define user commands to be executed by computer. Requires personal computer operating under MS-DOS with suitable hardware interfaces to all controlled devices. Also requires FORTRAN 77 compiler and device drivers written by user.

  3. Managing computer-controlled operations

    NASA Technical Reports Server (NTRS)

    Plowden, J. B.

    1985-01-01

    A detailed discussion of Launch Processing System Ground Software Production is presented to establish the interrelationships of firing room resource utilization, configuration control, system build operations, and Shuttle data bank management. The production of a test configuration identifier is traced from requirement generation to program development. The challenge of the operational era is to implement fully automated utilities to interface with a resident system build requirements document to eliminate all manual intervention in the system build operations. Automatic update/processing of Shuttle data tapes will enhance operations during multi-flow processing.

  4. Human/computer control of undersea teleoperators

    NASA Technical Reports Server (NTRS)

    Sheridan, T. B.; Verplank, W. L.; Brooks, T. L.

    1978-01-01

    The potential of supervisory controlled teleoperators for accomplishment of manipulation and sensory tasks in deep ocean environments is discussed. Teleoperators and supervisory control are defined, the current problems of human divers are reviewed, and some assertions are made about why supervisory control has potential use to replace and extend human diver capabilities. The relative roles of man and computer and the variables involved in man-computer interaction are next discussed. Finally, a detailed description of a supervisory controlled teleoperator system, SUPERMAN, is presented.

  5. [Computer-assisted tomography, B-scan sonography and cerebral angiography in obliterations of the carotid artery (author's transl)].

    PubMed

    Zeitler, E; Greiling, H W; Roth, F J; Friedmann, G

    1980-05-16

    The real-time-B-scan is a new and essential method for diagnosing carotid stenoses. Whereas computer-assisted tomography shows only a minor sensitivity for detection of obliterations of cervical arteries, B-scan sonography has high sensitivity and specificity. B-scans should be increasingly performed both after uncertain clinical and computer tomographic findings prior to angiography of extracranial cerebral vessels. A more stringent indication for angiography and thus avoidance of investigational and irradiation risk can be achieved. Wide use of B-scan sonography may, through early recognition of carotid obliterations, lead to prevention of cerebral insults as patients can undergo vascular surgery at an early stage. PMID:7371550

  6. Improved computed torque control for industrial robots

    NASA Technical Reports Server (NTRS)

    Uebel, Mark; Minis, Ioannis; Cleary, Kevin

    1992-01-01

    The authors examine the computed torque control problem for a robot arm with flexible, geared, joint drive systems which are typical in many industrial robots. The standard computed torque algorithm is not directly applicable to this class of manipulators due to the dynamics introduced by the joint drive systems. The proposed approach overcomes this problem by combining a novel computed torque algorithm with simple torque controllers at each joint of the robot. The control scheme is applied to a seven degree-of-freedom industrial manipulator, and the system performance in standard tasks is evaluated using both dynamic simulation and actual experiments. The results show that the proposed controller leads to improved tracking performance over a conventional PD (proportional plus derivative) controller.

  7. A computational framework for cancer response assessment based on oncological PET-CT scans.

    PubMed

    Sampedro, Frederic; Escalera, Sergio; Domenech, Anna; Carrio, Ignasi

    2014-12-01

    In this work we present a comprehensive computational framework to help in the clinical assessment of cancer response from a pair of time consecutive oncological PET-CT scans. In this scenario, the design and implementation of a supervised machine learning system to predict and quantify cancer progression or response conditions by introducing a novel feature set that models the underlying clinical context is described. Performance results in 100 clinical cases (corresponding to 200 whole body PET-CT scans) in comparing expert-based visual analysis and classifier decision making show up to 70% accuracy within a completely automatic pipeline and 90% accuracy when providing the system with expert-guided PET tumor segmentation masks. PMID:25450224

  8. Tetrahedron-based orthogonal simultaneous scan for cone-beam computed tomography

    PubMed Central

    Ye, Ivan B.; Wang, Ge

    2013-01-01

    In this article, a cone-beam computed tomography scanning mode is designed using four x-ray sources and a spherical sample. The x-ray sources are mounted at the vertices of a regular tetrahedron. On the circumsphere of the tetrahedron, four detection panels are mounted opposite of each vertex. To avoid x-ray interference, the largest half angle of each x-ray cone beam is 27°22′, while the radius of the largest ball fully covered by all the cone beams is 0.460, when the radius of the circumsphere is 1. A proposed scanning scheme consists of two rotations about orthogonal axes, such that, each quarter turn provides sufficient data for theoretically exact and stable reconstruction. This design can be used in biomedical or industrial settings, such as when a sequence of reconstructions of an object is desired. PMID:24058220

  9. Logical Access Control Mechanisms in Computer Systems.

    ERIC Educational Resources Information Center

    Hsiao, David K.

    The subject of access control mechanisms in computer systems is concerned with effective means to protect the anonymity of private information on the one hand, and to regulate the access to shareable information on the other hand. Effective means for access control may be considered on three levels: memory, process and logical. This report is a…

  10. Distributed computation of supremal conditionally controllable sublanguages

    NASA Astrophysics Data System (ADS)

    Komenda, Jan; Masopust, Tomáš

    2016-02-01

    In this paper, we further develop the coordination control framework for discrete-event systems with both complete and partial observations. First, a weaker sufficient condition for the computation of the supremal conditionally controllable sublanguage and conditionally normal sublanguage is presented. Then we show that this condition can be imposed by synthesising a-posteriori supervisors. The paper further generalises the previous study by considering general, non-prefix-closed languages. Moreover, we prove that for prefix-closed languages the supremal conditionally controllable sublanguage and conditionally normal sublanguage can always be computed in the distributed way without any restrictive conditions we have used in the past.

  11. Exploring dinosaur neuropaleobiology: viewpoint computed tomography scanning and analysis of an Allosaurus fragilis endocast.

    PubMed

    Rogers, S W

    1998-10-01

    The unique opportunity to examine an exceptionally well-preserved natural endocranial cast (endocast) from a carnivorous dinosaur of the late Jurassic period, Allosaurus fragilis, was afforded this neurobiologist. The endocast exhibits numerous surface features including the complete vestibular apparatus. Spiral computed tomography scanning revealed multiple internal features including putative blood vessels, connective tissue-like arrays, and a prominent symmetrical density consistent with the putative brain or its cast. The evidence suggests that this organism's neurobiology resembled closely that of modern crocodylian species and should be included for consideration when examining ideas of Allosaurus evolution, behavior, and eventual extinction. PMID:9808455

  12. A universal computer control system for motors

    NASA Technical Reports Server (NTRS)

    Szakaly, Zoltan F. (Inventor)

    1991-01-01

    A control system for a multi-motor system such as a space telerobot, having a remote computational node and a local computational node interconnected with one another by a high speed data link is described. A Universal Computer Control System (UCCS) for the telerobot is located at each node. Each node is provided with a multibus computer system which is characterized by a plurality of processors with all processors being connected to a common bus, and including at least one command processor. The command processor communicates over the bus with a plurality of joint controller cards. A plurality of direct current torque motors, of the type used in telerobot joints and telerobot hand-held controllers, are connected to the controller cards and responds to digital control signals from the command processor. Essential motor operating parameters are sensed by analog sensing circuits and the sensed analog signals are converted to digital signals for storage at the controller cards where such signals can be read during an address read/write cycle of the command processing processor.

  13. The Use of Computer Vision Algorithms for Automatic Orientation of Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Markiewicz, Jakub Stefan

    2016-06-01

    The paper presents analysis of the orientation of terrestrial laser scanning (TLS) data. In the proposed data processing methodology, point clouds are considered as panoramic images enriched by the depth map. Computer vision (CV) algorithms are used for orientation, which are applied for testing the correctness of the detection of tie points and time of computations, and for assessing difficulties in their implementation. The BRISK, FASRT, MSER, SIFT, SURF, ASIFT and CenSurE algorithms are used to search for key-points. The source data are point clouds acquired using a Z+F 5006h terrestrial laser scanner on the ruins of Iłża Castle, Poland. Algorithms allowing combination of the photogrammetric and CV approaches are also presented.

  14. Computational Prediction of Alanine Scanning and Ligand Binding Energetics in G-Protein Coupled Receptors

    PubMed Central

    Boukharta, Lars; Gutiérrez-de-Terán, Hugo; Åqvist, Johan

    2014-01-01

    Site-directed mutagenesis combined with binding affinity measurements is widely used to probe the nature of ligand interactions with GPCRs. Such experiments, as well as structure-activity relationships for series of ligands, are usually interpreted with computationally derived models of ligand binding modes. However, systematic approaches for accurate calculations of the corresponding binding free energies are still lacking. Here, we report a computational strategy to quantitatively predict the effects of alanine scanning and ligand modifications based on molecular dynamics free energy simulations. A smooth stepwise scheme for free energy perturbation calculations is derived and applied to a series of thirteen alanine mutations of the human neuropeptide Y1 receptor and series of eight analogous antagonists. The robustness and accuracy of the method enables univocal interpretation of existing mutagenesis and binding data. We show how these calculations can be used to validate structural models and demonstrate their ability to discriminate against suboptimal ones. PMID:24743773

  15. Computer hardware and software for robotic control

    NASA Technical Reports Server (NTRS)

    Davis, Virgil Leon

    1987-01-01

    The KSC has implemented an integrated system that coordinates state-of-the-art robotic subsystems. It is a sensor based real-time robotic control system performing operations beyond the capability of an off-the-shelf robot. The integrated system provides real-time closed loop adaptive path control of position and orientation of all six axes of a large robot; enables the implementation of a highly configurable, expandable testbed for sensor system development; and makes several smart distributed control subsystems (robot arm controller, process controller, graphics display, and vision tracking) appear as intelligent peripherals to a supervisory computer coordinating the overall systems.

  16. Arm CT scan

    MedlinePlus

    CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... Mosby; 2013:chap 57. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  17. Sinus CT scan

    MedlinePlus

    CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... 2014:chap 67. Shaw AS, Dixon AK. Multidetector computed tomography. In: Adam A, Dixon AK, eds. Grainger & Allison's ...

  18. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... Saunders; 2012:chap 11. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  19. Pelvic CT scan

    MedlinePlus

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... gov/pubmed/18381118 . Shaw AS, Dixon AK. Multidetector computed tomography. In: Grainger RC, Allison D, Adam, Dixon AK, ...

  20. Shoulder CT scan

    MedlinePlus

    CAT scan - shoulder; Computed axial tomography scan - shoulder; Computed tomography scan - shoulder; CT scan - shoulder ... Mosby; 2012:chap 57. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  1. [HEALTH PREDICTION INDICES OBTAINED WITH LOW-DOSE COMPUTER TOMOGRAPHY SCANS].

    PubMed

    Matkevich, E i; Sinitsyn, V e; Ivanov LV

    2015-01-01

    Purpose of the investigation was to make prognostic estimations of reductions in somatic morbidity and temporal disability, and tumor pathology using low-dose computer tomography (CT) scans and to compare with standard protocols. Mean effective radiation doses were determined based on the results of 1627 diagnostic CT investigations made in 2012-2014 at the Treatment and Rehabilitation Center of the Russian Ministry of Health. Low-dose CT scans of the head and thoracic, abdominal and small pelvis organs were obtained on a GE Discovery CT750 HD, and with the help of the ASIR and MBIR algorithms of iterative reconstruction. In comparison with a standard dose, a single CT scan with a dose reduced by 10-12 mSv predicts a decrease in total morbidity by 0.84-5.52% and temporal disability by 0.55-1.65% per 100 employees over a year; total risk of tumors and genetic effects reduced in 5 to 10 times, which may be equal to 40-90 cases per 100,000 of 30 y.o. males. PMID:26934792

  2. Detection of vertical root fractures in endodontically treated teeth by a cone beam computed tomography scan.

    PubMed

    Hassan, Bassam; Metska, Maria Elissavet; Ozok, Ahmet Rifat; van der Stelt, Paul; Wesselink, Paul Rudolf

    2009-05-01

    Our aim was to compare the accuracy of cone beam computed tomography (CBCT) scans and periapical radiographs (PRs) in detecting vertical root fractures (VRFs) and to assess the influence of root canal filling (RCF) on fracture visibility. Eighty teeth were endodontically prepared and divided into four groups. The teeth in groups A and B were artificially fractured, and teeth in groups C and D were not. Groups A and C were root filled. Four observers evaluated the CBCT scans and PR images. Sensitivity and specificity for VRF detection of CBCT were 79.4% and 92.5% and for PR were 37.1% and 95%, respectively. The specificity of CBCT was reduced (p = 0.032) by the presence of RCF, but its overall accuracy was not influenced (p = 0.654). Both the sensitivity (p = 0.006) and overall accuracy (p = 0.008) of PRs were reduced by the presence of RCF. The results showed an overall higher accuracy for CBCT (0.86) scans than PRs (0.66) for detecting VRF. PMID:19410091

  3. Computationally Lightweight Air-Traffic-Control Simulation

    NASA Technical Reports Server (NTRS)

    Knight, Russell

    2005-01-01

    An algorithm for computationally lightweight simulation of automated air traffic control (ATC) at a busy airport has been derived. The algorithm is expected to serve as the basis for development of software that would be incorporated into flight-simulator software, the ATC component of which is not yet capable of handling realistic airport loads. Software based on this algorithm could also be incorporated into other computer programs that simulate a variety of scenarios for purposes of training or amusement.

  4. Control electronics for a multi-laser/multi-detector scanning system

    NASA Technical Reports Server (NTRS)

    Kennedy, W.

    1980-01-01

    The Mars Rover Laser Scanning system uses a precision laser pointing mechanism, a photodetector array, and the concept of triangulation to perform three dimensional scene analysis. The system is used for real time terrain sensing and vision. The Multi-Laser/Multi-Detector laser scanning system is controlled by a digital device called the ML/MD controller. A next generation laser scanning system, based on the Level 2 controller, is microprocessor based. The new controller capabilities far exceed those of the ML/MD device. The first draft circuit details and general software structure are presented.

  5. NIF Integrated Computer Controls System Description

    SciTech Connect

    VanArsdall, P.

    1998-01-26

    This System Description introduces the NIF Integrated Computer Control System (ICCS). The architecture is sufficiently abstract to allow the construction of many similar applications from a common framework. As discussed below, over twenty software applications derived from the framework comprise the NIF control system. This document lays the essential foundation for understanding the ICCS architecture. The NIF design effort is motivated by the magnitude of the task. Figure 1 shows a cut-away rendition of the coliseum-sized facility. The NIF requires integration of about 40,000 atypical control points, must be highly automated and robust, and will operate continuously around the clock. The control system coordinates several experimental cycles concurrently, each at different stages of completion. Furthermore, facilities such as the NIF represent major capital investments that will be operated, maintained, and upgraded for decades. The computers, control subsystems, and functionality must be relatively easy to extend or replace periodically with newer technology.

  6. Modern control centers and computer networking

    SciTech Connect

    Dy-Liacco, T.E.

    1994-10-01

    The automation of power system operation is generally achieved with the implementation of two control centers, one for the operation of the generation-transmission system and the other for the operation of the distribution system. These control centers are referred to, respectively, as the energy management system (EMS) and the distribution management system (DMS). The EMS may consist of several control centers in a hierarchy. The DMS may be made up of several independent distribution control centers. This article features the fundamental design aspects of modern EMS and DMS control centers (computer networks, distributed processing, and distributed databases), the linking of computer networks, and the communications that support such internetworking. The extension of such networking beyond the confines of system operation to other corporate networks is now made practical by the maturing concepts of client-server architectures and by the availability of modern communication technologies.

  7. ASTEC: Controls analysis for personal computers

    NASA Technical Reports Server (NTRS)

    Downing, John P.; Bauer, Frank H.; Thorpe, Christopher J.

    1989-01-01

    The ASTEC (Analysis and Simulation Tools for Engineering Controls) software is under development at Goddard Space Flight Center (GSFC). The design goal is to provide a wide selection of controls analysis tools at the personal computer level, as well as the capability to upload compute-intensive jobs to a mainframe or supercomputer. The project is a follow-on to the INCA (INteractive Controls Analysis) program that has been developed at GSFC over the past five years. While ASTEC makes use of the algorithms and expertise developed for the INCA program, the user interface was redesigned to take advantage of the capabilities of the personal computer. The design philosophy and the current capabilities of the ASTEC software are described.

  8. A pixel-connecting algorithm for enhancement and segmentation of computed tomography scans

    SciTech Connect

    Yanof, J.H.

    1990-01-01

    The objective of the study was to enhance and segment X-ray Computerized Tomography (CT) scans. To deal with the noise and spatial complexity of these images, a relaxation algorithm was developed in order to link pixels together into homogeneous regions. Each pixel is assigned a set of weighted links to its nearest neighbors. The links are initially isotropic, and are arranged into stochastic link matrices. By computing powers of the link matrix, an object-dependent weighting mask for each pixel over an expanded neighborhood is found. The masks are used to compute a similarity measure between pixels in order to adjust the interlinks. The edges, which segment the image, are identified by the below-threshold links, and the displayed mask-weighted averages result in an enhanced image. The algorithm seems robust w.r.t. the five images tested: the images based on the weighted averages have a smooth appearance with sharpened edges. The algorithm has successfully segmented primary liver tumors of varying sizes and shapes. The links which drop below threshold highlight anatomical details of the scans which are difficult to visualize with the unaided eye.

  9. Utilizing computed tomography scans for analysis of motorcycle helmets in real-world crashes - biomed 2011.

    PubMed

    Loftis, Kathryn L; Moreno, Daniel P; Tan, Joshua; Gabler, Hampton C; Stitzel, Joel D

    2011-01-01

    In 2008, there were more than 5,000 motorcycle crash fatalities in the United States. Many states have motorcycle helmet laws that are meant to protect riders during a crash. After recruiting motorcycle occupants injured in crashes, a protocol was established to scan three different types of motorcycle helmets commonly worn (cap, ¾ shield, and full face shield) using a computed tomography (CT) scanner. The protocol developed was for a GE 64 slice PET/CT Discovery VCT scanner with axial images from anterior to posterior helmet acquired in helical mode. It had 512x512 resolution and the full face and ¾ face shield helmets were scanned with greater voxels in the axial plane compared to the skull cap helmets. New helmets were scanned as exemplary images for comparison with helmets involved in motorcycle crashes. After CT scans were gathered, three-dimensional reconstructions were made to visualize scratches and impacts to the exterior of the helmets. Initial work was also conducted in analyzing interior components, and a trend was seen in decreased thickness between the interior foam and shell with sides of the exterior helmet thought to have contacted roadside barriers or the ground during motorcycle crashes. These helmet analysis methods have been established, and will be used to investigate multiple motorcycle crashes in conjunction with occupant injuries and direct head impacts to improve helmet design and the understanding of head injuries. This work also establishes the basis for development of finite element models of three of the most common helmet types. PMID:21525626

  10. Computed Tomography (CT) Scanning Facilitates Early Identification of Neonatal Cystic Fibrosis Piglets

    PubMed Central

    Guillon, Antoine; Chevaleyre, Claire; Barc, Celine; Berri, Mustapha; Adriaensen, Hans; Lecompte, François; Villemagne, Thierry; Pezant, Jérémy; Delaunay, Rémi; Moënne-Loccoz, Joseph; Berthon, Patricia; Bähr, Andrea; Wolf, Eckhard; Klymiuk, Nikolai; Attucci, Sylvie; Ramphal, Reuben; Sarradin, Pierre; Buzoni-Gatel, Dominique; Si-Tahar, Mustapha; Caballero, Ignacio

    2015-01-01

    Background Cystic Fibrosis (CF) is the most prevalent autosomal recessive disease in the Caucasian population. A cystic fibrosis transmembrane conductance regulator knockout (CFTR-/-) pig that displays most of the features of the human CF disease has been recently developed. However, CFTR-/- pigs presents a 100% prevalence of meconium ileus that leads to death in the first hours after birth, requiring a rapid diagnosis and surgical intervention to relieve intestinal obstruction. Identification of CFTR-/- piglets is usually performed by PCR genotyping, a procedure that lasts between 4 to 6 h. Here, we aimed to develop a procedure for rapid identification of CFTR-/- piglets that will allow placing them under intensive care soon after birth and immediately proceeding with the surgical correction. Methods and Principal Findings Male and female CFTR+/- pigs were crossed and the progeny was examined by computed tomography (CT) scan to detect the presence of meconium ileus and facilitate a rapid post-natal surgical intervention. Genotype was confirmed by PCR. CT scan presented a 94.4% sensitivity to diagnose CFTR-/- piglets. Diagnosis by CT scan reduced the birth-to-surgery time from a minimum of 10 h down to a minimum of 2.5 h and increased the survival of CFTR-/- piglets to a maximum of 13 days post-surgery as opposed to just 66 h after later surgery. Conclusion CT scan imaging of meconium ileus is an accurate method for rapid identification of CFTR-/- piglets. Early CT detection of meconium ileus may help to extend the lifespan of CFTR-/- piglets and, thus, improve experimental research on CF, still an incurable disease. PMID:26600426

  11. Characterization of landslide ground surface kinematics from terrestrial laser scanning and strain field computation

    NASA Astrophysics Data System (ADS)

    Teza, Giordano; Pesci, Arianna; Genevois, Rinaldo; Galgaro, Antonio

    2008-05-01

    Assessment and mitigation of the risk induced by landslide activation need an appropriate phenomenon investigation, to obtain useful information about the failure processes. The first step is the complete kinematics characterization of the landslide ground surface, by evaluating the involved displacement and deformation patterns. A dense displacement field can be obtained from comparison of a series of multi-temporal observations performed by means of terrestrial laser scanning. Subsequently, the strain field can be computed from displacement vectors. In this paper, a modified least square technique is employed to compute the strain on the nodes of a regular grid (2D approach) or on the points of a digital terrain model (3D approach). Such a computation takes into account the displacements, their spatial distribution, as well as the measurement and modelling errors. A scale factor is introduced in order to emphasize the contributions of the experimental points on the basis of their distance from each computation point, and to recognize possible scale-depending behaviours. This method has been implemented in Matlab and applied on two landslides located in the northeastern Italian Alps (Lamosano and Perarolo di Cadore). The experiments show that different kinematics can be recognized, and the presence and influence of eventual discontinuities can be revealed.

  12. Scanning, Scanning, Everywhere.

    ERIC Educational Resources Information Center

    Ekhaml, Leticia; Myers, Brenda

    1997-01-01

    Discusses uses of scanning (process of copying or converting text, images, and objects into information that the computer can recognize and manipulate) in schools and notes possible desktop publishing projects. Describes popular scanners and ways to edit a scanned image. A sidebar gives costs and telephone numbers for nine scanners. (AEF)

  13. Intermittent control: a computational theory of human control.

    PubMed

    Gawthrop, Peter; Loram, Ian; Lakie, Martin; Gollee, Henrik

    2011-02-01

    The paradigm of continuous control using internal models has advanced understanding of human motor control. However, this paradigm ignores some aspects of human control, including intermittent feedback, serial ballistic control, triggered responses and refractory periods. It is shown that event-driven intermittent control provides a framework to explain the behaviour of the human operator under a wider range of conditions than continuous control. Continuous control is included as a special case, but sampling, system matched hold, an intermittent predictor and an event trigger allow serial open-loop trajectories using intermittent feedback. The implementation here may be described as "continuous observation, intermittent action". Beyond explaining unimodal regulation distributions in common with continuous control, these features naturally explain refractoriness and bimodal stabilisation distributions observed in double stimulus tracking experiments and quiet standing, respectively. Moreover, given that human control systems contain significant time delays, a biological-cybernetic rationale favours intermittent over continuous control: intermittent predictive control is computationally less demanding than continuous predictive control. A standard continuous-time predictive control model of the human operator is used as the underlying design method for an event-driven intermittent controller. It is shown that when event thresholds are small and sampling is regular, the intermittent controller can masquerade as the underlying continuous-time controller and thus, under these conditions, the continuous-time and intermittent controller cannot be distinguished. This explains why the intermittent control hypothesis is consistent with the continuous control hypothesis for certain experimental conditions. PMID:21327829

  14. Computer-Controlled HVAC -- at Low Cost

    ERIC Educational Resources Information Center

    American School and University, 1974

    1974-01-01

    By tying into a computerized building-automation network, Schaumburg High School, Illinois, slashed its energy consumption by one-third. The remotely connected computer controls the mechanical system for the high school as well as other buildings in the community, with the cost being shared by all. (Author)

  15. Central control element expands computer capability

    NASA Technical Reports Server (NTRS)

    Easton, R. A.

    1975-01-01

    Redundant processing and multiprocessing modes can be obtained from one computer by using logic configuration. Configuration serves as central control element which can automatically alternate between high-capacity multiprocessing mode and high-reliability redundant mode using dynamic mode switching in real time.

  16. Multiaxis Computer Numerical Control Internship Report

    ERIC Educational Resources Information Center

    Rouse, Sharon M.

    2012-01-01

    (Purpose) The purpose of this paper was to examine the issues associated with bringing new technology into the classroom, in particular, the vocational/technical classroom. (Methodology) A new Haas 5 axis vertical Computer Numerical Control machining center was purchased to update the CNC machining curriculum at a community college and the process…

  17. Scanning tunnelling microscope fabrication of arrays of phosphorus atom qubits for a silicon quantum computer

    NASA Astrophysics Data System (ADS)

    O'Brien, J. L.; Schofield, S. R.; Simmons, M. Y.; Clark, R. G.; Dzurak, A. S.; Curson, N. J.; Kane, B. E.; McAlpine, N. S.; Hawley, M. E.; Brown, G. W.

    2002-10-01

    Recognition of the potentially massive computational power of a quantum computer has driven a considerable experimental effort to build such a device. Of the various possible physical implementations, silicon-based architectures are attractive for the long spin relaxation times involved, their scalability, and ease of integration with existing silicon technology. However, their fabrication requires construction at the atomic scale - an immense technological challenge. Here we outline a detailed strategy for the construction of a phosphorus in silicon quantum computer and demonstrate the first significant step towards this goal - the fabrication of atomically precise arrays of single phosphorus bearing molecules on a silicon surface. After using a monolayer hydrogen resist to passivate a silicon surface we apply pulsed voltages to a scanning tunnelling microscope tip to selectively desorb individual hydrogen atoms with atomic resolution. Exposure of this surface to the phosphorus precursor phosphine results in precise placement of single phosphorus atoms on the surface. We also describe preliminary studies into a process to incorporate these surface phosphorus atoms into the silicon crystal at the array sites.

  18. National Ignition Facility integrated computer control system

    NASA Astrophysics Data System (ADS)

    Van Arsdall, Paul J.; Bettenhausen, R. C.; Holloway, Frederick W.; Saroyan, R. A.; Woodruff, J. P.

    1999-07-01

    The NIF design team is developing the Integrated Computer Control System (ICCS), which is based on an object-oriented software framework applicable to event-driven control system. The framework provides an open, extensive architecture that is sufficiently abstract to construct future mission-critical control systems. The ICCS will become operational when the first 8 out of 192 beams are activated in mid 2000. THe ICCS consists of 300 front-end processors attached to 60,000 control points coordinated by a supervisory system. Computers running either Solaris or VxWorks are networked over a hybrid configuration of switched fast Ethernet and asynchronous transfer mode (ATM). ATM carries digital motion video from sensor to operator consoles. Supervisory software is constructed by extending the reusable framework components for each specific application. The framework incorporates services for database persistence, system configuration, graphical user interface, status monitoring, event logging, scripting language, alert management, and access control. More than twenty collaborating software applications are derived from the common framework. The framework is interoperable among different kinds of computers and functions as a plug-in software bus by leveraging a common object request brokering architecture (CORBA). CORBA transparently distributes the software objects across the network. Because of the pivotal role played, CORBA was tested to ensure adequate performance.

  19. Computation and control with neural nets

    SciTech Connect

    Corneliusen, A.; Terdal, P.; Knight, T.; Spencer, J.

    1989-10-04

    As energies have increased exponentially with time so have the size and complexity of accelerators and control systems. NN may offer the kinds of improvements in computation and control that are needed to maintain acceptable functionality. For control their associative characteristics could provide signal conversion or data translation. Because they can do any computation such as least squares, they can close feedback loops autonomously to provide intelligent control at the point of action rather than at a central location that requires transfers, conversions, hand-shaking and other costly repetitions like input protection. Both computation and control can be integrated on a single chip, printed circuit or an optical equivalent that is also inherently faster through full parallel operation. For such reasons one expects lower costs and better results. Such systems could be optimized by integrating sensor and signal processing functions. Distributed nets of such hardware could communicate and provide global monitoring and multiprocessing in various ways e.g. via token, slotted or parallel rings (or Steiner trees) for compatibility with existing systems. Problems and advantages of this approach such as an optimal, real-time Turing machine are discussed. Simple examples are simulated and hardware implemented using discrete elements that demonstrate some basic characteristics of learning and parallelism. Future microprocessors' are predicted and requested on this basis. 19 refs., 18 figs.

  20. National Ignition Facility integrated computer control system

    SciTech Connect

    Van Arsdall, P.J., LLNL

    1998-06-01

    The NIF design team is developing the Integrated Computer Control System (ICCS), which is based on an object-oriented software framework applicable to event-driven control systems. The framework provides an open, extensible architecture that is sufficiently abstract to construct future mission-critical control systems. The ICCS will become operational when the first 8 out of 192 beams are activated in mid 2000. The ICCS consists of 300 front-end processors attached to 60,000 control points coordinated by a supervisory system. Computers running either Solaris or VxWorks are networked over a hybrid configuration of switched fast Ethernet and asynchronous transfer mode (ATM). ATM carries digital motion video from sensors to operator consoles. Supervisory software is constructed by extending the reusable framework components for each specific application. The framework incorporates services for database persistence, system configuration, graphical user interface, status monitoring, event logging, scripting language, alert management, and access control. More than twenty collaborating software applications are derived from the common framework. The framework is interoperable among different kinds of computers and functions as a plug-in software bus by leveraging a common object request brokering architecture (CORBA). CORBA transparently distributes the software objects across the network. Because of the pivotal role played, CORBA was tested to ensure adequate performance.

  1. A Monte Carlo tool for raster-scanning particle therapy dose computation

    NASA Astrophysics Data System (ADS)

    Jelen, U.; Radon, M.; Santiago, A.; Wittig, A.; Ammazzalorso, F.

    2014-03-01

    Purpose of this work was to implement Monte Carlo (MC) dose computation in realistic patient geometries with raster-scanning, the most advanced ion beam delivery technique, combining magnetic beam deflection with energy variation. FLUKA, a Monte Carlo package well-established in particle therapy applications, was extended to simulate raster-scanning delivery with clinical data, unavailable as built-in feature. A new complex beam source, compatible with FLUKA public programming interface, was implemented in Fortran to model the specific properties of raster-scanning, i.e. delivery by means of multiple spot sources with variable spatial distributions, energies and numbers of particles. The source was plugged into the MC engine through the user hook system provided by FLUKA. Additionally, routines were provided to populate the beam source with treatment plan data, stored as DICOM RTPlan or TRiP98's RST format, enabling MC recomputation of clinical plans. Finally, facilities were integrated to read computerised tomography (CT) data into FLUKA. The tool was used to recompute two representative carbon ion treatment plans, a skull base and a prostate case, prepared with analytical dose calculation (TRiP98). Selected, clinically relevant issues influencing the dose distributions were investigated: (1) presence of positioning errors, (2) influence of fiducial markers and (3) variations in pencil beam width. Notable differences in modelling of these challenging situations were observed between the analytical and Monte Carlo results. In conclusion, a tool was developed, to support particle therapy research and treatment, when high precision MC calculations are required, e.g. in presence of severe density heterogeneities or in quality assurance procedures.

  2. Computational Controls Workstation: Algorithms and hardware

    NASA Technical Reports Server (NTRS)

    Venugopal, R.; Kumar, M.

    1993-01-01

    The Computational Controls Workstation provides an integrated environment for the modeling, simulation, and analysis of Space Station dynamics and control. Using highly efficient computational algorithms combined with a fast parallel processing architecture, the workstation makes real-time simulation of flexible body models of the Space Station possible. A consistent, user-friendly interface and state-of-the-art post-processing options are combined with powerful analysis tools and model databases to provide users with a complete environment for Space Station dynamics and control analysis. The software tools available include a solid modeler, graphical data entry tool, O(n) algorithm-based multi-flexible body simulation, and 2D/3D post-processors. This paper describes the architecture of the workstation while a companion paper describes performance and user perspectives.

  3. Scanning protocol optimization and dose evaluation in coronary stenosis using multi-slices computed tomography

    NASA Astrophysics Data System (ADS)

    Huang, Yung-hui; Chen, Chia-lin; Sheu, Chin-yin; Lee, Jason J. S.

    2007-02-01

    Cardiovascular diseases are the most common incidence for premature death in developed countries. A major fraction is attributable to atherosclerotic coronary artery disease, which may result in sudden cardiac failure. A reduction of mortality caused by myocardial infarction may be achieved if coronary atherosclerosis can be detected and treated at an early stage before symptoms occur. Therefore, there is need for an effective tool that allows identification of patients at increased risk for future cardiac events. The current multi-detector CT has been widely used for detection and quantification of coronary calcifications as a sign of coronary atherosclerosis. The aim of this study is to optimize the diagnostic values and radiation exposure in coronary artery calcium-screening examination using multi-slice CT (MSCT) with different image scan protocols. The radiation exposure for all protocols is evaluated by using computed tomography dose index (CTDI) phantom measurements. We chose an optimal scanning protocol and evaluated patient radiation dose in the MSCT coronary artery screenings and preserved its expecting diagnostic accuracy. These changes make the MSCT have more operation flexibility and provide more diagnostic values in current practice.

  4. A negative cranial computed tomographic scan is not adequate to support a diagnosis of pseudotumor cerebri.

    PubMed

    Said, Rana R; Rosman, N Paul

    2004-08-01

    A 10-year-old boy with daily headache for 1 month and intermittent diplopia for 1 week was found to have a unilateral partial abducens palsy and bilateral papilledema; otherwise, his neurologic examination showed no abnormalities. A cranial computed tomographic (CT) scan was normal. Lumbar puncture disclosed a markedly elevated opening pressure of > 550 mm of cerebrospinal fluid with normal cerebrospinal fluid. Medical therapy with acetazolamide for presumed pseudotumor cerebri was begun. Magnetic resonance imaging (MRI) of the brain, done several days later because of continuing symptoms, unexpectedly showed multiple hyperintensities of cerebral white matter on T2-weighted and fluid-attenuated inversion recovery images. Despite high-dose intravenous methylprednisolone for possible demyelinating disease, he failed to improve. A left temporal brain biopsy followed and disclosed an anaplastic oligodendroglioma. In a patient with features indicating pseudotumor cerebri, a negative cranial CT scan is not adequate to rule out underlying pathology; thus, MRI of the brain should probably always be performed. A revised definition of pseudotumor cerebri could better include "normal MRI of the brain" rather than "normal neuroimaging." PMID:15605471

  5. Examination of Scanning Electron Microscope and Computed Tomography Images of PICA

    NASA Technical Reports Server (NTRS)

    Lawson, John W.; Stackpoole, Margaret M.; Shklover, Valery

    2010-01-01

    Micrographs of PICA (Phenolic Impregnated Carbon Ablator) taken using a Scanning Electron Microscope (SEM) and 3D images taken with a Computed Tomography (CT) system are examined. PICA is a carbon fiber based composite (Fiberform ) with a phenolic polymer matrix. The micrographs are taken at different surface depths and at different magnifications in a sample after arc jet testing and show different levels of oxidative removal of the charred matrix (Figs 1 though 13). CT scans, courtesy of Xradia, Inc. of Concord CA, were captured for samples of virgin PICA, charred PICA and raw Fiberform (Fig. 14). We use these images to calculate the thermal conductivity (TC) of these materials using correlation function (CF) methods. CF methods give a mathematical description of how one material is embedded in another and is thus ideally suited for modeling composites like PICA. We will evaluate how the TC of the materials changes as a function of surface depth. This work is in collaboration with ETH-Zurich, which has expertise in high temperature materials and TC modeling (including CF methods).

  6. Abdominal computed tomographic scan-merits and demerits over ultrasonography: evaluation of 70 cases.

    PubMed

    Obajimi, M O; Ogunseyinde, A O; Agunloye, A M

    2002-06-01

    Computed tomography (CT) and Ultrasonography (USS) are commonly used to ascertain the cause of abdominal symptoms. In a retrospective study of 70 Nigerian patients who had abdominal ultrasonography prior to abdominal CT scans, the most frequent clinical feature was abdominal pain, which was reported in 20.8% of the patients. The prevalent ultrasonographic finding was hepatomegaly (12.2%) while bowel displacement was the most frequently reported CT finding (18.3%). There was no correlation between USS and CT findings in 11 patients (15.7%). There was some agreement in the findings of both tests in 75.7% of cases. Additional findings were noted in 38 (54.3%) of the latter group of patients on CT scans. Hundred percent agreement was reported in both imaging techniques in 5 radiological findings namely: dilated gall bladder, renal cysts, ascites, adrenal mass and utero-cervical mass. These findings suggest a high yield of diagnostic accuracy from abdominal sonography and increased diagnostic details provided by CT imaging. Our overall impression is that the diagnostic information provided by the two techniques are complimentary. PMID:12518911

  7. Computer morphing of scanning electron micrographs: an adjunct to embryology teaching.

    PubMed

    Watt, M E; McDonald, S W; Watt, A

    1996-01-01

    Traditional embryology courses demand considerable expenditure of time and effort from students to master the spatial awareness skills necessary to create three-dimensional mental images from two-dimensional serial sections. Then students must imagine a movie sequence of the changes which take place during normal development. Further steps are required to relate this information to the clinical situation. As more medical and dental schools move towards problem-based curricula, more efficient methods of improving understanding of embryology are needed. The development of many organs can be studied using scanning electron micrographs of embryos at different ages. These high quality images are more easily interpreted by our students than histological sections and the understanding achieved more readily applied to clinical problems. Still more beneficial would be the provision of moving images showing the actual changes happening. We decided to use computer morphing techniques to prepare movie sequences showing development of the face and plate. For each, four scanning electron micrographs of appropriately-sized sheep embryo heads were taken at the same magnification and orientation to use as start and end points of morphing sequences. After using retouching techniques to colour the separate processes, further sequences were prepared. The discipline of maintaining the same magnification throughout and the possibility of directly observing changes between stages revealed some surprising growth patterns. This technique is adaptable to any area of biological development where pre- and post-illustrations are available. Animations can be presented on computer or on video and incorporated into programs. Student feedback has been very favourable. PMID:8983113

  8. GMXPBSA 2.0: A GROMACS tool to perform MM/PBSA and computational alanine scanning

    NASA Astrophysics Data System (ADS)

    Paissoni, C.; Spiliotopoulos, D.; Musco, G.; Spitaleri, A.

    2014-11-01

    GMXPBSA 2.0 is a user-friendly suite of Bash/Perl scripts for streamlining MM/PBSA calculations on structural ensembles derived from GROMACS trajectories, to automatically calculate binding free energies for protein-protein or ligand-protein complexes. GMXPBSA 2.0 is flexible and can easily be customized to specific needs. Additionally, it performs computational alanine scanning (CAS) to study the effects of ligand and/or receptor alanine mutations on the free energy of binding. Calculations require only for protein-protein or protein-ligand MD simulations. GMXPBSA 2.0 performs different comparative analysis, including a posteriori generation of alanine mutants of the wild-type complex, calculation of the binding free energy values of the mutant complexes and comparison of the results with the wild-type system. Moreover, it compares the binding free energy of different complexes trajectories, allowing the study the effects of non-alanine mutations, post-translational modifications or unnatural amino acids on the binding free energy of the system under investigation. Finally, it can calculate and rank relative affinity to the same receptor utilizing MD simulations of proteins in complex with different ligands. In order to dissect the different MM/PBSA energy contributions, including molecular mechanic (MM), electrostatic contribution to solvation (PB) and nonpolar contribution to solvation (SA), the tool combines two freely available programs: the MD simulations software GROMACS and the Poisson-Boltzmann equation solver APBS. All the calculations can be performed in single or distributed automatic fashion on a cluster facility in order to increase the calculation by dividing frames across the available processors. The program is freely available under the GPL license. Catalogue identifier: AETQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETQ_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing

  9. Open questions in computational motor control.

    PubMed

    Karniel, Amir

    2011-09-01

    Computational motor control covers all applications of quantitative tools for the study of the biological movement control system. This paper provides a review of this field in the form of a list of open questions. After an introduction in which we define computational motor control, we describe: a Turing-like test for motor intelligence; internal models, inverse model, forward model, feedback error learning and distal teacher; time representation, and adaptation to delay; intermittence control strategies; equilibrium hypotheses and threshold control; the spatiotemporal hierarchy of wide sense adaptation, i.e., feedback, learning, adaptation, and evolution; optimization based models for trajectory formation and optimal feedback control; motor memory, the past and the future; and conclude with the virtue of redundancy. Each section in this paper starts with a review of the relevant literature and a few more specific studies addressing the open question, and ends with speculations about the possible answer and its implications to motor neuroscience. This review is aimed at concisely covering the topic from the author's perspective with emphasis on learning mechanisms and the various structures and limitations of internal models. PMID:21960308

  10. Computational modeling and multilevel cancer control interventions.

    PubMed

    Morrissey, Joseph P; Lich, Kristen Hassmiller; Price, Rebecca Anhang; Mandelblatt, Jeanne

    2012-05-01

    This chapter presents an overview of computational modeling as a tool for multilevel cancer care and intervention research. Model-based analyses have been conducted at various "beneath the skin" or biological scales as well as at various "above the skin" or socioecological levels of cancer care delivery. We review the basic elements of computational modeling and illustrate its applications in four cancer control intervention areas: tobacco use, colorectal cancer screening, cervical cancer screening, and racial disparities in access to breast cancer care. Most of these models have examined cancer processes and outcomes at only one or two levels. We suggest ways these models can be expanded to consider interactions involving three or more levels. Looking forward, a number of methodological, structural, and communication barriers must be overcome to create useful computational models of multilevel cancer interventions and population health. PMID:22623597

  11. Cerebral metabolic rate of glucose computed by Bayes regression of deoxyglucose PET scans

    SciTech Connect

    Wilson, P.D.; Links, J.M.; Huang, S.C.; Douglass, K.H.; Wong, D.F.; Frost, J.J.; Wagner, H.N. Jr.

    1984-01-01

    Local cerebral metabolic rate of glucose (LCMRG) is currently measured using a PET scan of deoxyglucose at 40-60 min postinjection and computed using assumed mean normal rate constants. While the method is accurate in normal tissue, another study showed that for ischemic regions the use of mean normal rate constants underestimated LCMRG by 50%. The authors used computer simulation to study the use of Bayes Regression, a useful method for combining prior information with patient data to estimate the patient's LCMRG. Prior information (means and variances of rate constants in the population) is combined with the patient's data with weighting factors determined by the variances of the rate constants in the population and the noise in the data. The authors simulated noisy data from both a normal and an ischemic population. Each simulation was based on different randomly-selected rate constants from the parent population. They compared the current method with Bayes Regression in each of 100 simulated experiments in each of 3 cases: (1) normal patient, normal prior; (2) ischemic patient, ischemic prior; (3) ischemic patient, normal prior. In patients with ischemic, Bayes Regression appears to provide truer estimates of LCMRG.

  12. Vibration Pattern Imager (VPI): A control and data acquisition system for scanning laser vibrometers

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A.; Brown, Donald E.; Shaffer, Thomas A.

    1993-01-01

    The Vibration Pattern Imager (VPI) system was designed to control and acquire data from scanning laser vibrometer sensors. The PC computer based system uses a digital signal processing (DSP) board and an analog I/O board to control the sensor and to process the data. The VPI system was originally developed for use with the Ometron VPI Sensor, but can be readily adapted to any commercially available sensor which provides an analog output signal and requires analog inputs for control of mirror positioning. The sensor itself is not part of the VPI system. A graphical interface program, which runs on a PC under the MS-DOS operating system, functions in an interactive mode and communicates with the DSP and I/O boards in a user-friendly fashion through the aid of pop-up menus. Two types of data may be acquired with the VPI system: single point or 'full field.' In the single point mode, time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and is stored by the PC. The position of the measuring point (adjusted by mirrors in the sensor) is controlled via a mouse input. The mouse input is translated to output voltages by the D/A converter on the I/O board to control the mirror servos. In the 'full field' mode, the measurement point is moved over a user-selectable rectangular area. The time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and converted to a root-mean-square (rms) value by the DSP board. The rms 'full field' velocity distribution is then uploaded for display and storage on the PC.

  13. A COMPUTATIONAL NEUROANATOMY FOR MOTOR CONTROL

    PubMed Central

    Shadmehr, Reza; Krakauer, John W.

    2008-01-01

    The study of patients to infer normal brain function has a long tradition in neurology and psychology. More recently, the motor system has been subject to quantitative and computational characterization. The purpose of this review is to argue that the lesion approach and theoretical motor control can mutually inform each other. Specifically, one may identify distinct motor control processes from computational models and map them onto specific deficits in patients. Here we review some of the impairments in motor control, motor learning and higher-order motor control in patients with lesions of the corticospinal tract, the cerebellum, parietal cortex, the basal ganglia, and the medial temporal lobe. We attempt to explain some of these impairments in terms of computational ideas such as state estimation, optimization, prediction, cost, and reward. We suggest that a function of the cerebellum is system identification: to built internal models that predict sensory outcome of motor commands and correct motor commands through internal feedback. A function of the parietal cortex is state estimation: to integrate the predicted proprioceptive and visual outcomes with sensory feedback to form a belief about how the commands affected the states of the body and the environment. A function of basal ganglia is related to optimal control: learning costs and rewards associated with sensory states and estimating the “cost-to-go” during execution of a motor task. Finally, functions of the primary and the premotor cortices are related to implementing the optimal control policy by transforming beliefs about proprioceptive and visual states, respectively, into motor commands. PMID:18251019

  14. A computer-based digital feedback control of frequency drift of multiple lasers

    NASA Astrophysics Data System (ADS)

    Zhao, W. Z.; Simsarian, J. E.; Orozco, L. A.; Sprouse, G. D.

    1998-11-01

    We report a method to monitor and control laser frequencies with an optical cavity and a digital feedback system. A frequency-stabilized He-Ne laser provides the reference that is transferred to several other lasers using a scanning Fabry-Pérot cavity. A personal computer-based multifunction data acquisition system generates the scan wave form, and reads the detector outputs synchronously with the cavity scan. The computer determines the positions of all of the peaks in the scan, and generates output signals to control the laser frequencies. It also provides a visual display of cavity spectra. We have successfully used the setup to achieve a long-term lock of the lasers for magneto-optical trapping of radioactive francium atoms.

  15. Zeno effect for quantum computation and control.

    PubMed

    Paz-Silva, Gerardo A; Rezakhani, A T; Dominy, Jason M; Lidar, D A

    2012-02-24

    It is well known that the quantum Zeno effect can protect specific quantum states from decoherence by using projective measurements. Here we combine the theory of weak measurements with stabilizer quantum error correction and detection codes. We derive rigorous performance bounds which demonstrate that the Zeno effect can be used to protect appropriately encoded arbitrary states to arbitrary accuracy while at the same time allowing for universal quantum computation or quantum control. PMID:22463507

  16. Adapting Inspection Data for Computer Numerical Control

    NASA Technical Reports Server (NTRS)

    Hutchison, E. E.

    1986-01-01

    Machining time for repetitive tasks reduced. Program converts measurements of stub post locations by coordinate-measuring machine into form used by numerical-control computer. Work time thus reduced by 10 to 15 minutes for each post. Since there are 600 such posts on each injector, time saved per injector is 100 to 150 hours. With modifications this approach applicable to machining of many precise holes on large machine frames and similar objects.

  17. Computer control of rf at SLAC

    SciTech Connect

    Schwarz, H.D.

    1985-03-01

    The Stanford Linear Accelerator is presently upgraded for the SLAC Linear Collider project. The energy is to be increased from approximately 31 GeV to 50 GeV. Two electron beams and one positron beam are to be accelerated with high demands on the quality of the beams. The beam specifications are shown. To meet these specifications, all parameters influencing the beams have to be under tight control and continuous surveillance. This task is accomplished by a new computer system implemented at SLAC which has, among many other functions, control over rf accelerating fields. 13 refs., 8 figs., 2 tabs.

  18. Computer controls for the WITCH experiment

    NASA Astrophysics Data System (ADS)

    Tandecki, M.; Beck, D.; Beck, M.; Brand, H.; Breitenfeldt, M.; De Leebeeck, V.; Friedag, P.; Herlert, A.; Kozlov, V.; Mader, J.; Roccia, S.; Soti, G.; Traykov, E.; Van Gorp, S.; Wauters, F.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

    2011-02-01

    The WITCH experiment is a medium-scale experimental set-up located at ISOLDE/CERN. It combines a double Penning trap system with a retardation spectrometer for energy measurements of recoil ions from β decay. For a correct operation of such a set-up a whole range of different devices is required. Along with the installation and optimization of the set-up a computer control system was developed to control these devices. The CS-Framework that is developed and maintained at GSI, was chosen as a basis for this control system as it is perfectly suited to handle the distributed nature of a control system.We report here on the required hardware for WITCH, along with the basis of this CS-Framework and the add-ons that were implemented for WITCH.

  19. Predictors of unsuccessful magnetic resonance imaging scanning in older generalized anxiety disorder patients and controls.

    PubMed

    Mohlman, Jan; Eldreth, Dana A; Price, Rebecca B; Chazin, Daniel; Glover, Dorie A

    2012-02-01

    A thorough understanding of the neurobiology of late life anxiety is likely to depend on the use of brain imaging techniques such as magnetic resonance imaging (MRI). Generalized anxiety disorder (GAD) is one of the most prevalent anxiety disorders in older adults, and is thus a focus for neurobiological studies using MRI. This study tested 1-3 weeks predictors of unsuccessful scan outcomes (i.e., scan trials in which the participant moved excessively or prematurely terminated the scan) in older adults with GAD (n = 39) and age- and sex-matched nonanxious controls (n = 21). It was hypothesized that successful completion of a prior MRI scan, clinical status (GAD versus control), and scores on the Anxiety Sensitivity Index (ASI; Peterson et al. 1986), a measure tapping psychological aspects of medical interventions, would predict scan outcome when current diagnoses of claustrophobia were controlled. In logistic regression analyses, unsuccessful scan outcome was predicted by prior MRI completion and ASI Mental Concerns subscale scores, but not clinical status. This model correctly classified 91% of successful and 71% of unsuccessful scans. An alternative model that included a single ASI item rather than Mental Concerns subscale scores showed similar performance, and a model including categorical anxiety sensitivity groups was also effective but slightly less accurate. Implications for improving the success rates of MRI with older adults are discussed. PMID:21318410

  20. Computer Interfaced Image Tube Intensified Self-Scanned Array Cameras And Instruments

    NASA Astrophysics Data System (ADS)

    Johnson, C. B.; Blank, R. E.

    1984-01-01

    Image tube intensified linear and area self-scanned array (SSA) readout detector assemblies are becoming increasingly important for automatic inspection systems and machine vision. Proximity focused diode and microchannel plate (MCP) image intensifier tubes are being used in conjunction with SSAs because they can be electronically gated, they are physically small, they do not introduce image distortion, and for several other reasons 11,12,30-33. Even single photon events can be detected by using high gain MCP image tubes. Image intensified linear SSA (IL/SSA) detector assemblies can now provide successive 100% duty cycle optical samples in time periods as short as 1 ms for up to 1024 linear array pixels with 8 or 12 bit parallel output. Image intensified area SSA (IA/SSA) detector assemblies with, for example, 488 x 380 pixels in the active image area, can be read out in 33 ms. Both IL/SSA and IA/SSA detector assemblies can be interfaced to computers directly, or through conventional data acquisition systems (DASs) 14,15,35,45,48,51. Depending upon the maximum input data rate to the computer, the DAS either operates in the continuous-mode or in the burst-mode. Virtually any type of linear or area SSA can be image tube intensified and computer interfaced using the methods described 38,42. A new 512 or 1024 pixel IL/SSA instrument detector assembly, the F4560, coupled to an HP-85 microcomputer through an HP-6942A DAS has been developed.

  1. A voice coil motor based measuring force control system for tactile scanning profiler

    NASA Astrophysics Data System (ADS)

    Feng, Shengdong; Liu, Xiaojun; Chen, Liangzhou; Zhou, Liping; Lu, Wenlong

    2015-02-01

    In tactile scanning profiler, the measuring force would change in a wide range when it was used for profile measurement in a large range, which could possibly destroy the measured surface. To solve the problem, measuring force control system for tactile scanning profiler was needed. In the paper, a voice coil motor-based measuring force control system for tactile scanning profiler was designed. In the design, a low stiffness coefficient spring was used to provide contact force, while a voice coil motor (VCM) to balance the spring force so that the contact force could be kept for constant measuring force. A VCM was designed specially, and for active measuring force control, a precision current source circuit under the control of a DSP unit was designed to drive the VCM. The performance of voice coil motor based measuring force control system had been tested, and its good characteristics were verified.

  2. Measurement of Optimal Insertion Angle for Iliosacral Screw Fixation Using Three-Dimensional Computed Tomography Scans

    PubMed Central

    Kim, Jung-Jae; Jung, Chul-Young; Eastman, Jonathan G.

    2016-01-01

    Background Percutaneous iliosacral screw fixation can provide stable fixation with a minimally invasive surgical technique for unstable posterior pelvic ring injuries. This surgical technique is not limited by cases of difficult fracture patterns, sacral dysplasia, and small sacral pedicles that can occur in Asians. The purpose of this study was to investigate the incidence of the sacral dysplasia in the Korean population and determine the optimal direction of iliosacral screws by analyzing pelvic three-dimensional computed tomography (3D-CT) scans. Methods One hundred adult patients who had pelvic 3D-CT scans were evaluated. The upper sacral morphology was classified into three groups, i.e., normal, transitional, and dysplastic groups; the cross-sectional area of the safe zone was measured in each group. S1 pedicle with a short width of more than 11 mm was defined as safe pedicle. The incidences of safe pedicles at different angles ranging from 0° to 15° were investigated in order to determine optimal angle for screw direction. Results The incidence of normal, transitional, and dysplastic group was 46%, 32%, and 22%, respectively. There were significant increases of the cross-sectional area of the safe zones by increasing the angles from 0° to 15° in all groups. The incidence of safe pedicles increased similar to the changes in cross-sectional area. The overall incidence of safe pedicles was highest at the 10° tilt angle. Conclusions The incidence of sacral dysplasia in Koreans was 54%, which is higher than previous studies for Western populations. The cross-sectional area of the safe zone can be increased by anteromedial direction of the iliosacral screw. Considering the diversity of sacral morphology present in the Korean population, a tilt angle of 10° may be the safest angle. PMID:27247736

  3. High-resolution X-ray computed tomography scanning of primate copulatory plugs.

    PubMed

    Parga, Joyce A; Maga, Murat; Overdorff, Deborah J

    2006-04-01

    In this study, high-resolution computed tomography X-ray scanning was used to scan ring-tailed lemur (Lemur catta) copulatory plugs. This method produced accurate measures of plug volume and surface area, but was not useful for visualizing plug internal structure. Copulatory plug size was of interest because it may relate to male fertilization success. Copulatory plugs form from coagulated ejaculate, and are routinely displaced in this species by the penis of a subsequent mate during copulation (Parga [2003] Int. J. Primatol. 24:889-899). Because one potential function of these plugs may be to preclude or delay other males' successful insemination of females, we tested the hypothesis that larger plugs are more difficult for subsequent males to displace. Plugs were collected opportunistically upon displacement during data collection on L. catta mating behavior on St. Catherines Island, Georgia (USA) during two subsequent breeding seasons. Copulatory plugs exhibited a wide range of volumes: 1,758-5,013.6 mm3 (n = 9). Intraindividual differences in plug volume were sometimes greater than interindividual differences. Contrary to predictions, larger plugs were not more time-consuming for males to displace via penile intromission during copulation. Nor were plugs with longer vaginal residence times notably smaller than plugs with shorter residence times, as might be expected if plugs disintegrate while releasing sperm (Asdell [1946] Patterns of Mammalian Reproduction; Ithaca: Comstock). We found a significant inverse correlation between number of copulatory mounts leading to ejaculation and copulatory plug volume. This may indicate that if males are sufficiently sexually aroused to reach ejaculation in fewer mounts, they tend to produce ejaculates of greater volume. PMID:16345065

  4. A computer-controlled x-ray imaging scanner using a kinestatic charge detector

    NASA Astrophysics Data System (ADS)

    Wagenaar, Douglas J.; DiBianca, Frank A.; Tenney, Charles R.; Vance, Joseph E.; Reed, Mark S. C.; Wilson, Donald W.; Dollas, Apostolos; McDaniel, David L.; Granfors, Paul; Petrick, Scott

    1990-02-01

    A prototype scanning imaging system which employs a kinestatic charge detector (KCD) and is under the control of a VAXstation II/GPX computer is described. The operating principles and advantages of the KCD method are reviewed. The detector is a 256-channel ionization drift chamber which creates a two-dimensional x-ray projection image by scanning the detector past the object of interest. The details of the drift chamber design, the signal collection electrodes (channels), and the Frisch grid geometry are given. Also described are the scanning gantry design, computer-controlled drive motor circuit, and safety features. The data acquisition system for the capture of a 1 M byte digital image is presented. This includes amplification, filtration, analog-to-digital conversion, data buffering, and transfer to the VAXstation II computer. The image processing and display techniques specific to the KCD are outlined and the first two-dimensional image taken with this system is presented.

  5. Operator control of interneural computing machines.

    PubMed

    Shih, Mau-Hsiang; Tsai, Feng-Sheng

    2013-12-01

    A dynamic representation of neural population responses asserts that motor cortex is a flexible pattern generator sending rhythmic, oscillatory signals to generate multiphasic patterns of movement. This raises a question concerning the design and control of new computing machines that mimic the oscillatory patterns and multiphasic patterns seen in neural systems. To address this issue, we design an interneural computing machine (INCM) made of plastic random interneural connections. We develop a mechanical way to measure collective ensemble firing of neurons in INCM. Two sorts of plasticity operators are derived from the measure of synchronous neural activity and the measure of self-sustaining neural activity, respectively. Such plasticity operators conduct activity-dependent operation to modify the network structure of INCM. The activity-dependent operation meets the neurobiological perspective of Hebbian synaptic plasticity and displays the tendency toward circulation breaking aiming to control neural population dynamics. We call such operation operator control of INCM and develop a population analysis of operator control for measuring how well single neurons of INCM can produce rhythmic, oscillatory activity, but at the level of neural ensembles, generate multiphasic patterns of population responses. PMID:24805217

  6. Superadiabatic Controlled Evolutions and Universal Quantum Computation

    PubMed Central

    Santos, Alan C.; Sarandy, Marcelo S.

    2015-01-01

    Adiabatic state engineering is a powerful technique in quantum information and quantum control. However, its performance is limited by the adiabatic theorem of quantum mechanics. In this scenario, shortcuts to adiabaticity, such as provided by the superadiabatic theory, constitute a valuable tool to speed up the adiabatic quantum behavior. Here, we propose a superadiabatic route to implement universal quantum computation. Our method is based on the realization of piecewise controlled superadiabatic evolutions. Remarkably, they can be obtained by simple time-independent counter-diabatic Hamiltonians. In particular, we discuss the implementation of fast rotation gates and arbitrary n-qubit controlled gates, which can be used to design different sets of universal quantum gates. Concerning the energy cost of the superadiabatic implementation, we show that it is dictated by the quantum speed limit, providing an upper bound for the corresponding adiabatic counterparts. PMID:26511064

  7. Superadiabatic Controlled Evolutions and Universal Quantum Computation

    NASA Astrophysics Data System (ADS)

    Santos, Alan C.; Sarandy, Marcelo S.

    2015-10-01

    Adiabatic state engineering is a powerful technique in quantum information and quantum control. However, its performance is limited by the adiabatic theorem of quantum mechanics. In this scenario, shortcuts to adiabaticity, such as provided by the superadiabatic theory, constitute a valuable tool to speed up the adiabatic quantum behavior. Here, we propose a superadiabatic route to implement universal quantum computation. Our method is based on the realization of piecewise controlled superadiabatic evolutions. Remarkably, they can be obtained by simple time-independent counter-diabatic Hamiltonians. In particular, we discuss the implementation of fast rotation gates and arbitrary n-qubit controlled gates, which can be used to design different sets of universal quantum gates. Concerning the energy cost of the superadiabatic implementation, we show that it is dictated by the quantum speed limit, providing an upper bound for the corresponding adiabatic counterparts.

  8. Knee CT scan

    MedlinePlus

    CAT scan - knee; Computed axial tomography scan - knee; Computed tomography scan - knee ... Saunders; 2015:chap 93. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  9. Lumbar spine CT scan

    MedlinePlus

    CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... stopping.) A computer creates separate images of the spine area, called slices. These images can be stored, ...

  10. Upgrade for the NSTX Control Computer

    SciTech Connect

    D. Mueller; D.A. Gates; J.R. Ferron

    1999-06-01

    The National Spherical Torus Experiment (NSTX) is a proof of scientific principle experiment as a magnetic fusion containment device. A primary goal of NSTX operations is control of the plasma current, position and shape in real time for a wide range of plasma pressure and current density profiles. In order to employ the best calculation of the plasma current, position and shape, it is planned to implement the equilibrium analysis code, EFIT, in real-time, RTEFIT. EFIT inverts the Grad-Shafranov equation and performs a least squares fit to the magnetics data. RTEFIT is also capable of providing the plasma current profile and the plasma pressure profile from analysis of diagnostic data. The calculation time for RTEFTI using the present NSTX control computer system is comparable to the expected energy confinement time on NSTX and is thus slower than desired. A computer upgrade based upon 604e processors will permit the RTEFIT calculation loop to complete in about 3 ms. The presence of the passive plates further complicates the control algorithm to be used in conjunction with RTEFIT. The planned approach is to measure the eddy currents in the passive plates and to use the transient response of the coils to minimize the total shell current effect.

  11. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

    2014-09-01

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

  12. Cephalometric Angular Measurements of the Mandible Using Three-Dimensional Computed Tomography Scans in Koreans

    PubMed Central

    Kim, Yong Hyun; Kang, Seok Joo

    2016-01-01

    Background We conducted this study to analyze the values of the key cephalometric angular measurements of the mandible using 3-dimensional (3D) computed tomography scans. Methods In the 106 enrolled patients, a 3D cephalometric analysis was performed to measure the angular variables of the mandible. These values were compared between the two sides and between the two sexes. Results The frontal measurements revealed that the mandibular body curve angle was larger on the left (Lt) side (right [Rt], 141.24±7.54; Lt, 142.68±6.94; P=0.002) and the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P<0.001). The sagittal measurements showed that the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P>0.05). Further, the transverse measurements revealed that the mandibular body curve angle was larger on the right side (Rt, 140.28±7.05; Lt, 137.56±6.23; P<0.001). Conclusions These results provide an average of the mandibular angular measurements for the Korean population, establishing a standard for determining surgical patient groups and outcome evaluations in the field of mandible contour surgery. PMID:26848443

  13. Unveiling Stability Criteria of DNA-Carbon Nanotubes Constructs by Scanning Tunneling Microscopy and Computational Modeling

    DOE PAGESBeta

    Kilina, Svetlana; Yarotski, Dzmitry A.; Talin, A. Alec; Tretiak, Sergei; Taylor, Antoinette J.; Balatsky, Alexander V.

    2011-01-01

    We present a combined approach that relies on computational simulations and scanning tunneling microscopy (STM) measurements to reveal morphological properties and stability criteria of carbon nanotube-DNA (CNT-DNA) constructs. Application of STM allows direct observation of very stable CNT-DNA hybrid structures with the well-defined DNA wrapping angle of 63.4 ° and a coiling period of 3.3 nm. Using force field simulations, we determine how the DNA-CNT binding energy depends on the sequence and binding geometry of a single strand DNA. This dependence allows us to quantitatively characterize the stability of a hybrid structure with an optimal π-stacking between DNA nucleotides andmore » the tube surface and better interpret STM data. Our simulations clearly demonstrate the existence of a very stable DNA binding geometry for (6,5) CNT as evidenced by the presence of a well-defined minimum in the binding energy as a function of an angle between DNA strand and the nanotube chiral vector. This novel approach demonstrates the feasibility of CNT-DNA geometry studies with subnanometer resolution and paves the way towards complete characterization of the structural and electronic properties of drug-delivering systems based on DNA-CNT hybrids as a function of DNA sequence and a nanotube chirality.« less

  14. Computer simulation of RF liver ablation on an MRI scan data

    NASA Astrophysics Data System (ADS)

    Kosturski, N.; Margenov, S.; Vutov, Y.

    2012-10-01

    Radio-frequency (RF) ablation is a low invasive technique for treatment of liver tumors. An RF-probe is inserted in the patient's liver and a ground pad is applied to the skin. Then the tumor is heated with RF current. The heat causes the destruction of tumor cells. We use the finite element method (FEM) to simulate and analyze various aspects of the procedure. A 3D image of the patient's liver is obtained from a magnetic resonance imaging (MRI) scan. Then, the geometry for the RFprobe and the ground pad is added. Our focus is on the influence of the position of the ground pads on the ablation process. Our simulation is based on an unstructured mesh. The size of the mesh is large due to the complexity of the domain. We discretize and solve the problem on a parallel computer using MPI for the parallelization. The presented numerical tests are performed on IBM Blue Gene/P machine at BGSC. The parallel efficiency of the incorporated Boomer AMG solver is demonstrated as well.

  15. Multiaxis, Lightweight, Computer-Controlled Exercise System

    NASA Technical Reports Server (NTRS)

    Haynes, Leonard; Bachrach, Benjamin; Harvey, William

    2006-01-01

    The multipurpose, multiaxial, isokinetic dynamometer (MMID) is a computer-controlled system of exercise machinery that can serve as a means for quantitatively assessing a subject s muscle coordination, range of motion, strength, and overall physical condition with respect to a wide variety of forces, motions, and exercise regimens. The MMID is easily reconfigurable and compactly stowable and, in comparison with prior computer-controlled exercise systems, it weighs less, costs less, and offers more capabilities. Whereas a typical prior isokinetic exercise machine is limited to operation in only one plane, the MMID can operate along any path. In addition, the MMID is not limited to the isokinetic (constant-speed) mode of operation. The MMID provides for control and/or measurement of position, force, and/or speed of exertion in as many as six degrees of freedom simultaneously; hence, it can accommodate more complex, more nearly natural combinations of motions and, in so doing, offers greater capabilities for physical conditioning and evaluation. The MMID (see figure) includes as many as eight active modules, each of which can be anchored to a floor, wall, ceiling, or other fixed object. A cable is payed out from a reel in each module to a bar or other suitable object that is gripped and manipulated by the subject. The reel is driven by a DC brushless motor or other suitable electric motor via a gear reduction unit. The motor can be made to function as either a driver or an electromagnetic brake, depending on the required nature of the interaction with the subject. The module includes a force and a displacement sensor for real-time monitoring of the tension in and displacement of the cable, respectively. In response to commands from a control computer, the motor can be operated to generate a required tension in the cable, to displace the cable a required distance, or to reel the cable in or out at a required speed. The computer can be programmed, either locally or via

  16. Computer-controlled radiation monitoring system

    SciTech Connect

    Homann, S.G.

    1994-09-27

    A computer-controlled radiation monitoring system was designed and installed at the Lawrence Livermore National Laboratory`s Multiuser Tandem Laboratory (10 MV tandem accelerator from High Voltage Engineering Corporation). The system continuously monitors the photon and neutron radiation environment associated with the facility and automatically suspends accelerator operation if preset radiation levels are exceeded. The system has proved reliable real-time radiation monitoring over the past five years, and has been a valuable tool for maintaining personnel exposure as low as reasonably achievable.

  17. GMXPBSA 2.0: A GROMACS tool to perform MM/PBSA and computational alanine scanning

    NASA Astrophysics Data System (ADS)

    Paissoni, C.; Spiliotopoulos, D.; Musco, G.; Spitaleri, A.

    2014-11-01

    GMXPBSA 2.0 is a user-friendly suite of Bash/Perl scripts for streamlining MM/PBSA calculations on structural ensembles derived from GROMACS trajectories, to automatically calculate binding free energies for protein-protein or ligand-protein complexes. GMXPBSA 2.0 is flexible and can easily be customized to specific needs. Additionally, it performs computational alanine scanning (CAS) to study the effects of ligand and/or receptor alanine mutations on the free energy of binding. Calculations require only for protein-protein or protein-ligand MD simulations. GMXPBSA 2.0 performs different comparative analysis, including a posteriori generation of alanine mutants of the wild-type complex, calculation of the binding free energy values of the mutant complexes and comparison of the results with the wild-type system. Moreover, it compares the binding free energy of different complexes trajectories, allowing the study the effects of non-alanine mutations, post-translational modifications or unnatural amino acids on the binding free energy of the system under investigation. Finally, it can calculate and rank relative affinity to the same receptor utilizing MD simulations of proteins in complex with different ligands. In order to dissect the different MM/PBSA energy contributions, including molecular mechanic (MM), electrostatic contribution to solvation (PB) and nonpolar contribution to solvation (SA), the tool combines two freely available programs: the MD simulations software GROMACS and the Poisson-Boltzmann equation solver APBS. All the calculations can be performed in single or distributed automatic fashion on a cluster facility in order to increase the calculation by dividing frames across the available processors. The program is freely available under the GPL license. Catalogue identifier: AETQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETQ_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing

  18. Feedback/feedforward control of hysteresis-compensated piezoelectric actuators for high-speed scanning applications

    NASA Astrophysics Data System (ADS)

    Liu, Yanfang; Shan, Jinjun; Gabbert, Ulrich

    2015-01-01

    This paper presents the control system design for a piezoelectric actuator (PEA) for a high-speed trajectory scanning application. First nonlinear hysteresis is compensated for by using the Maxwell resistive capacitor model. Then the linear dynamics of the hysteresis-compensated piezoelectric actuator are identified. A proportional plus integral (PI) controller is designed based on the linear system, enhanced by feedforward hysteresis compensation. It is found that the feedback controller does not always improve tracking accuracy. When the input frequency exceeds a certain value, feedforward control only may result in better control performance. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

  19. PREDICTING CHEMICAL REACTIVITY OF HUMIC SUBSTANCES FOR MINERALS AND XENOBIOTICS: USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY AND VIRTUAL REALITY

    EPA Science Inventory

    In this chapter we review the literature on scanning probe microscopy (SPM), virtual reality (VR), and computational chemistry and our earlier work dealing with modeling lignin, lignin-carbohydrate complexes (LCC), humic substances (HSs) and non-bonded organo-mineral interactions...

  20. Optimization and quality control of computed radiography

    NASA Astrophysics Data System (ADS)

    Willis, Charles E.; Weiser, John C.; Leckie, Robert G.; Romlein, John R.; Norton, Gary S.

    1994-05-01

    Computed radiography (CR) is a relatively new technique for projection radiography. Few hospitals have CR devices in routine service and only a handful have more than one CR unit. As such, the clinical knowledge base does not yet exist to establish quality control (QC) procedures for CR devices. Without assurance that CR systems are operating within nominal limits, efforts to optimize CR performance are limited in value. A complete CR system includes detector plates that vary in response, cassettes, an electro-optical system for developing the image, computer algorithms for processing the raw image, and a hard copy output device. All of these subsystems are subject to variations in performance that can degrade image quality. Using CR manufacturer documentation, we have defined acceptance protocols for two different Fuji CR devices, the FCR 7000 and the AC1+, and have applied these tests to ten individual machines. We have begun to establish baseline performance measures and to determine measurement frequencies. CR QC is only one component of the overall quality control for totally digital radiology departments.

  1. A novel quality control procedure for the evaluation of laser scanning data segmentation

    NASA Astrophysics Data System (ADS)

    Lari, Z.; Al-Durgham, K.; Habib, A.

    2014-11-01

    Over the past few years, laser scanning systems have been acknowledged as the leading tools for the collection of high density 3D point cloud over physical surfaces for many different applications. However, no interpretation and scene classification is performed during the acquisition of these datasets. Consequently, the collected data must be processed to extract the required information. The segmentation procedure is usually considered as the fundamental step in information extraction from laser scanning data. So far, various approaches have been developed for the segmentation of 3D laser scanning data. However, none of them is exempted from possible anomalies due to disregarding the internal characteristics of laser scanning data, improper selection of the segmentation thresholds, or other problems during the segmentation procedure. Therefore, quality control procedures are required to evaluate the segmentation outcome and report the frequency of instances of expected problems. A few quality control techniques have been proposed for the evaluation of laser scanning segmentation. These approaches usually require reference data and user intervention for the assessment of segmentation results. In order to resolve these problems, a new quality control procedure is introduced in this paper. This procedure makes hypotheses regarding potential problems that might take place in the segmentation process, detects instances of such problems, quantifies the frequency of these problems, and suggests possible actions to remedy them. The feasibility of the proposed approach is verified through quantitative evaluation of planar and linear/cylindrical segmentation outcome from two recently-developed parameter-domain and spatial-domain segmentation techniques.

  2. Assessment of cardiac single-photon emission computed tomography performance using a scanning linear observer

    SciTech Connect

    Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana

    2013-01-15

    Purpose: Single-photon emission computed tomography (SPECT) is widely used to detect myocardial ischemia and myocardial infarction. It is important to assess and compare different SPECT system designs in order to achieve the highest detectability of cardiac defects. Methods: Whitaker et al.'s study ['Estimating random signal parameters from noisy images with nuisance parameters: linear and scanning-linear methods,' Opt. Express 16(11), 8150-8173 (2008)] on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than with reconstruction data. Thus, this observer model assesses the overall hardware performance independent of any reconstruction algorithm. In addition, the computation time of image quality studies is significantly reduced. In this study, three systems based on the design of the GE cadmium zinc telluride-based dedicated cardiac SPECT camera Discovery 530c were assessed. This design, which is officially named the Alcyone Technology: Discovery NM 530c, was commercialized in August, 2009. The three systems, GE27, GE19, and GE13, contain 27, 19, and 13 detectors, respectively. Clinically, a human heart can be virtually segmented into three coronary artery territories: the left-anterior descending artery, left-circumflex artery, and right coronary artery. One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can accurately predict in which territory the defect exists [http://www.asnc.org/media/PDFs/PPReporting081511.pdf, Guideline from American Society of Nuclear Cardiology]. A good estimation of the extent of the defect from the projection images is also very helpful for determining the seriousness of the myocardial ischemia. In this study, both the location and extent of defects were estimated by the SLO, and the system performance was assessed by localization

  3. Assessment of cardiac single-photon emission computed tomography performance using a scanning linear observer

    PubMed Central

    Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana

    2013-01-01

    Purpose: Single-photon emission computed tomography (SPECT) is widely used to detect myocardial ischemia and myocardial infarction. It is important to assess and compare different SPECT system designs in order to achieve the highest detectability of cardiac defects. Methods:Whitaker ’s study [“Estimating random signal parameters from noisy images with nuisance parameters: linear and scanning-linear methods,” Opt. Express 16(11), 8150–8173 (2008)]10.1364/OE.16.008150 on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than with reconstruction data. Thus, this observer model assesses the overall hardware performance independent of any reconstruction algorithm. In addition, the computation time of image quality studies is significantly reduced. In this study, three systems based on the design of the GE cadmium zinc telluride-based dedicated cardiac SPECT camera Discovery 530c were assessed. This design, which is officially named the Alcyone Technology: Discovery NM 530c, was commercialized in August, 2009. The three systems, GE27, GE19, and GE13, contain 27, 19, and 13 detectors, respectively. Clinically, a human heart can be virtually segmented into three coronary artery territories: the left-anterior descending artery, left-circumflex artery, and right coronary artery. One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can accurately predict in which territory the defect exists [http://www.asnc.org/media/PDFs/PPReporting081511.pdf, Guideline from American Society of Nuclear Cardiology]. A good estimation of the extent of the defect from the projection images is also very helpful for determining the seriousness of the myocardial ischemia. In this study, both the location and extent of defects were estimated by the SLO, and the system performance was assessed by

  4. GMXPBSA 2.1: A GROMACS tool to perform MM/PBSA and computational alanine scanning

    NASA Astrophysics Data System (ADS)

    Paissoni, C.; Spiliotopoulos, D.; Musco, G.; Spitaleri, A.

    2015-01-01

    GMXPBSA 2.1 is a user-friendly suite of Bash/Perl scripts for streamlining MM/PBSA calculations on structural ensembles derived from GROMACS trajectories, to automatically calculate binding free energies for protein-protein or ligand-protein complexes [R.T. Bradshaw et al., Protein Eng. Des. Sel. 24 (2011) 197-207]. GMXPBSA 2.1 is flexible and can easily be customized to specific needs and it is an improvement of the previous GMXPBSA 2.0 [C. Paissoni et al., Comput. Phys. Commun. (2014), 185, 2920-2929]. Additionally, it performs computational alanine scanning (CAS) to study the effects of ligand and/or receptor alanine mutations on the free energy of binding. Calculations require only for protein-protein or protein-ligand MD simulations. GMXPBSA 2.1 performs different comparative analyses, including a posteriori generation of alanine mutants of the wild-type complex, calculation of the binding free energy values of the mutant complexes and comparison of the results with the wild-type system. Moreover, it compares the binding free energy of different complex trajectories, allowing the study of the effects of non-alanine mutations, post-translational modifications or unnatural amino acids on the binding free energy of the system under investigation. Finally, it can calculate and rank relative affinity to the same receptor utilizing MD simulations of proteins in complex with different ligands. In order to dissect the different MM/PBSA energy contributions, including molecular mechanic (MM), electrostatic contribution to solvation (PB) and nonpolar contribution to solvation (SA), the tool combines two freely available programs: the MD simulations software GROMACS [S. Pronk et al., Bioinformatics 29 (2013) 845-854] and the Poisson-Boltzmann equation solver APBS [N.A. Baker et al., Proc. Natl. Acad. Sci. U.S.A 98 (2001) 10037-10041]. All the calculations can be performed in single or distributed automatic fashion on a cluster facility in order to increase the

  5. Establishment of optimal scan delay for multi-phase computed tomography using bolus-tracking technique in canine pancreas.

    PubMed

    Choi, Soo-Young; Choi, Ho-Jung; Lee, Ki-Ja; Lee, Young-Won

    2015-09-01

    To establish a protocol for a multi-phase computed tomography (CT) of the canine pancreas using the bolus-tracking technique, dynamic scan and multi-phase CT were performed in six normal beagle dogs. The dynamic scan was performed for 60 sec at 1-sec intervals after the injection (4 ml/sec) of a contrast medium, and intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were measured. The multi-phase CT with 3 phases was performed three times using a bolus-tracking technique. Scan delays were 0, 15 and 30 in first multi-phase scan; 5, 20 and 35 in second multi-phase scan; and 10, 25 and 40 sec in third multi-phase scan, respectively. Attenuation values and contrast enhancement pattern were analyzed from the aorta, pancreas and portal vein. The intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were 3.8 ± 0.7, 8.7 ± 0.9 and 13.3 ± 1.5 sec, respectively. The maximum attenuation values of the aorta, pancreatic parenchyma and portal vein were present at scan sections with no scan delay, a 5-sec delay and a 10-sec delay, respectively. When a multi-phase CT of the canine pancreas is triggered at aortic enhancement appearance using a bolus-tracking technique, the recommended optimal delay times of the arterial and pancreatic parenchymal phases are no scan delay and 5 sec, respectively. PMID:25843155

  6. Comparison of ultrasonography, computed tomography and 99mTc liver scan in diagnosis of Budd-Chiari syndrome.

    PubMed Central

    Gupta, S; Barter, S; Phillips, G W; Gibson, R N; Hodgson, H J

    1987-01-01

    Ultrasonography, computed tomography and 99mTc liver scanning are all useful in diagnosis of patients with the Budd-Chiari syndrome. In a study to determine their comparative value characteristic findings were recorded in all nine patients at ultrasonography and in seven patients at computed tomography. In contrast 99mTc liver scan showed a characteristic pattern in only one of eight patients. In our experience intrahepatic venous abnormalities were seen better at ultrasonography than at computed tomography. In addition, abnormality in the direction of blood flow could be detected by pulsed Doppler examination. Ultrasonography is relatively inexpensive, readily accessible, does not require administration of radiation or contrast agents and therefore should be the primary non-invasive investigation of patients with Budd-Chiari syndrome, or those at risk of developing it. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:3552905

  7. Digital computer control of a 30-cm mercury ion thruster

    NASA Technical Reports Server (NTRS)

    Low, C. A., Jr.

    1975-01-01

    The major objective was to define the exact role of an onboard spacecraft computer in the control of ion thrusters. An initial computer control system with accurate high speed capability was designed, programmed, and tested with the computer as the sole control element for an operating ion thruster. The command functions and a code format for a spacecraft digital control system were established. A second computer control system was constructed to operate with these functions and format. A throttle program sequence was established and tested. A two thruster array was tested with these computer control systems and the results reported.

  8. Digital computer control of a 30 cm mercury ion thruster

    NASA Technical Reports Server (NTRS)

    Low, C. A., Jr.

    1975-01-01

    The major objective of this program was to define the exact role of an on-board spacecraft computer in the control of ion thrusters. An initial computer control system with accurate high speed capability was designed, programmed, and tested with the computer as the sole control element for an operating ion thruster. The command functions and a code format for a spacecraft digital control system were established. A second computer control system was constructed to operate with these functions and format. A throttle program sequence was established and tested. A two thruster array was tested with these computer control systems and the results reported.

  9. A COMPUTER-CONTROLLED VAPOR-DILUTION OLFACTOMETER

    EPA Science Inventory

    A computer-controlled olfactometer with several innovations leading to closer control over the stimulus parameters and minimization of nonolfactory cues is presented. A microcomputer is used to control the stimulus duration and interstimulus interval. Electronic mass flow control...

  10. A flexible implementation of scanning probe microscopy utilizing a multifunction system linked to a PC-Pentium controller

    NASA Astrophysics Data System (ADS)

    Barchesi, C.; Cricenti, A.; Generosi, R.; Giammichele, C.; Luce, M.; Rinaldi, M.

    1997-10-01

    A flexible electronic setup on a PC platform and the software implementation in Windows Microsoft environment, for a multipurpose head for scanning probe microscopy (SPM), has been developed. The integrated, multiapplication data acquisition system is linked to a PC-Pentium controller, through a digital I/O board, and consists of: (i) an asynchronous acquisition for real time removal of following error from SPM images; (ii) a three-axes, computer controlled micropositioning stage; (iii) software for electronic control, data acquisition, and graphics elaboration performed through subroutines of Visual Basic (Visual Basic Programming System Professional edition for Windows is a registered trademark of Microsoft Corporation, USA.), and PV-WAVE personal edition. (PV-WAVE Personal edition for Windows is a registered trademark of Visual Numerics, USA.)

  11. Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight

    PubMed Central

    2011-01-01

    Background The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose. Methods One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population. Results Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters. Conclusions A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques. PMID:22004072

  12. Determination of dominant fibre orientations in fibre-reinforced high-strength concrete elements based on computed tomography scans

    NASA Astrophysics Data System (ADS)

    Vicente, Miguel A.; González, Dorys C.; Mínguez, Jesús

    2014-04-01

    Computed tomography (CT) is a nondestructive technique, based on absorbing X-rays, that permits the visualisation of the internal structure of materials in micron-range resolution. In this paper, the CT scan is used to determine the position and orientation of the fibres in steel fibre-reinforced high-strength concrete elements. The aim of this paper was to present a numerical procedure, automated through a MATLAB routine specially developed by the authors, which enables, fast and reliable, to obtain the orientation of each and every one of the fibres and their centre of gravity. The procedure shown is directly extrapolated to any type of fibre-reinforced material, only if there is a wide difference between density of fibres and density of matrix. The mathematical basis of this procedure is very simple and robust. The result is a fast algorithm and a routine easy to use. In addition, the validation tests show that the error is almost zero. This algorithm can help the industry to implement the technology of CT in the protocols of product quality control.

  13. Unusual cause for recurrent Cushing syndrome and its diagnosis by computed tomography and NP-59 radiocholesterol scanning

    SciTech Connect

    Harris, R.D.; Herwig, K.R. )

    1990-09-01

    Cushing syndrome can recur following an adrenalectomy. One of the primary causes is recurrence of adrenal carcinoma either locally or from metastases. Hyperplasia and hyperfunction of adrenal remnants may also occur if there is pituitary stimulation. We have a patient in whom recurrent Cushing syndrome developed from small nonmalignant deposits of adrenal tissue in the perirenal adipose tissue following adrenalectomy of a benign adenoma. These deposits were identifiable by computed tomography. A false-negative NP-59 iodocholesterol scan was instructive in pointing out some problems in the interpretation of this type of scan for adrenal tissue.

  14. A 4D dose computation method to investigate motion interplay effects in scanned ion beam prostate therapy

    NASA Astrophysics Data System (ADS)

    Ammazzalorso, F.; Jelen, U.

    2014-06-01

    In particle therapy, the interplay between beam scanning and target motion during treatment delivery may result in dose deterioration. Interplay effects have been studied for targets exhibiting periodic respiratory motion, however, they are not well understood for irregular motion patterns, such as those exhibited by the prostate. In this note, we propose and validate a 4D dose computation method, which enables estimation of effective dose delivered to the prostate by scanning ion beams in presence of intrafraction motion, as well as facilitates investigation of various motion interplay countermeasures.

  15. INFLUENCE OF LOCALIZER AND SCAN DIRECTION ON THE DOSE-REDUCING EFFECT OF AUTOMATIC TUBE CURRENT MODULATION IN COMPUTED TOMOGRAPHY.

    PubMed

    Franck, C; Bacher, K

    2016-06-01

    The purpose of this study was to investigate the influence of the localizer and scan direction on the dose-reducing efficacy of the automatic tube current modulation (ATCM) in computed tomography (CT). Craniocaudal and caudocranial chest CT scans, based on anterior-posterior (AP), posterior-anterior (PA), lateral (LAT) or dual AP/LAT localizers, of an anthropomorphic phantom containing thermoluminescent dosimeters (TLDs), were made on three Siemens systems. TLD readings were converted to lung and thyroid doses. A second dose estimation was performed based on Monte Carlo simulations. In addition, the ATCM behaviour of GE and Toshiba was evaluated based on AP, PA and LAT localizers. Compared with AP, tube currents of PA and AP/LAT scans were on average 20 % higher and 40 % lower, respectively, for the Siemens systems. Consequently, thyroid and lung doses increased with 60 % with a PA instead of an AP/LAT scan, with significant differences in image noise. Moreover, the thyroid dose halves by taking the scan in caudocranial direction. Noise values were not significantly different when changing scan direction. PMID:27056145

  16. Evaluation of post-mortem lateral cerebral ventricle changes using sequential scans during post-mortem computed tomography.

    PubMed

    Hasegawa, Iwao; Shimizu, Akinobu; Saito, Atsushi; Suzuki, Hideto; Vogel, Hermann; Püschel, Klaus; Heinemann, Axel

    2016-09-01

    In the present study, we evaluated post-mortem lateral cerebral ventricle (LCV) changes using computed tomography (CT). Subsequent periodical CT scans termed "sequential scans" were obtained for three cadavers. The first scan was performed immediately after the body was transferred from the emergency room to the institute of legal medicine. Sequential scans were obtained and evaluated for 24 h at maximum. The time of death had been determined in the emergency room. The sequential scans enabled us to observe periodical post-mortem changes in CT images. The series of continuous LCV images obtained up to 24 h (two cases)/16 h (1 case) after death was evaluated. The average Hounsfield units (HU) within the LCVs progressively increased, and LCV volume progressively decreased over time. The HU in the cerebrospinal fluid (CSF) increased at an individual rate proportional to the post-mortem interval (PMI). Thus, an early longitudinal radiodensity change in the CSF could be potential indicator of post-mortem interval (PMI). Sequential imaging scans reveal post-mortem changes in the CSF space which may reflect post-mortem brain alterations. Further studies are needed to evaluate the proposed CSF change markers in correlation with other validated PMI indicators. PMID:27048214

  17. Direct control and characterization of a Schottky barrier by scanning tunneling microscopy

    NASA Technical Reports Server (NTRS)

    Bell, L. D.; Kaiser, W. J.; Hecht, M. H.; Grunthaner, F. J.

    1988-01-01

    Scanning tunneling microscopy (STM) methods are used to directly control the barrier height of a metal tunnel tip-semiconductor tunnel junction. Barrier behavior is measured by tunnel current-voltage spectroscopy and compared to theory. A unique surface preparation method is used to prepare a low surface state density Si surface. Control of band bending with this method enables STM investigation of semiconductor subsurface properties.

  18. Three-Dimensional Reconstruction of Human Vocal Folds and Standard Laryngeal Cartilages Using Computed Tomography Scan Data

    PubMed Central

    Bakhshaee, Hani; Moro, Christina; Kost, Karen; Mongeau, Luc

    2013-01-01

    Summary Three-dimensional (3D) computer models of the human larynx are useful tools for research and for eventual clinical applications. Recently, computed tomography (CT) scanning and magnetic resonance imaging (MRI) have been used to recreate realistic models of human larynx. In the present study, CT images were used to create computer models of vocal folds, vocal tract, and laryngeal cartilages, and the procedure to create solid models are explained in details. Vocal fold and vocal tract 3D models of healthy and postsurgery larynges during phonation and respiration were created and morphometric parameters were quantified. The laryngeal framework of eight patients was also reconstructed from CT scan images. For each cartilage, morphometric landmarks were measured on the basis of their importance for biomechanical modeling. A quantitative comparison was made between measured values from the reconstructions and those from human excised larynges in literature. The good agreement between these measurements supports the accuracy of CT scan-based 3D models. Generic standard models of the laryngeal framework were created using known features in modeling softwares. They were created based on the morphometric landmark dimensions previously defined, preserving all biomechanically important dimensions. These models are accessible, subject independent, easy to use for computational simulations, and make the comparisons between different studies possible. PMID:24119643

  19. Instrument scanning and controlling: Using eye movement data to understand pilot behavior and strategies

    NASA Technical Reports Server (NTRS)

    Dick, A. O.

    1980-01-01

    Eye movement data and other parameters including instrument readings, aircraft state and position variables, and control maneuvers were recorded while pilots flew ILS simulations in a B 737. The experiment itself employed seven airline pilots, each of whom flew approximately 40 approach/landing sequences. The simulator was equipped with a night visual scene but the scene was fogged out down to approximately 60 meters (200 ft). The instrument scanning appeared to follow aircraft parameters not physical position of instruments. One important implication of the results is: pilots look for categories or packets of information. Control inputs were tabulated according to throttle, wheel position, column, and pitch trim changes. Three seconds of eye movements before and after the control input were then obtained. Analysis of the eye movement data for the controlling periods showed clear patterns. The results suggest a set of miniscan patterns which are used according to the specific details of the situation. A model is developed which integrates scanning and controlling. Differentiations are made between monitoring and controlling scans.

  20. Radiology of pulmonary disease. Chest radiography, computed tomography, and gallium scanning

    SciTech Connect

    Golden, J.A.; Sollitto, R.A.

    1988-09-01

    A review of the radiologic manifestations of AIDS pulmonary diseases, with an emphasis on the utility of gallium scanning in the context of the normal or equivocal chest x-ray, is presented.99 references.

  1. Novel control scheme for a high-speed metrological scanning probe microscope

    NASA Astrophysics Data System (ADS)

    Vorbringer-Dorozhovets, N.; Hausotte, T.; Manske, E.; Shen, J. C.; Jäger, G.

    2011-09-01

    Some time ago, an interferometer-based metrological scanning probe microscope (SPM) was developed at the Institute of Process Measurement and Sensor Technology of the Ilmenau University of Technology, Germany. The specialty of this SPM is the combined deflection detection system that comprises an interferometer and a beam deflection. Due to this system it is possible to simultaneously measure the displacement, bending and torsion of the probe (cantilever). The SPM is integrated into a nanopositioning and nanomeasuring machine (NPM machine) and allows measurements with a resolution of 0.1 nm over a range of 25 mm × 25 mm × 5 mm. Excellent results were achieved for measurements of calibrated step height and lateral standards and these results are comparable to the calibration values from the Physikalisch-Technische Bundesanstalt (PTB) (Dorozhovets N et al 2007 Proc. SPIE 6616 661624-1-7). The disadvantage was a low attainable scanning speed and accordingly large expenditure of time. Control dynamics and scanning speed are limited because of the high masses of the stage and corner mirror of the machine. For the vertical axis an additional high-speed piezoelectric drive is integrated in the SPM in order to increase the measuring dynamics. The movement of the piezoelectric drive is controlled and traceable measured by the interferometer. Hence, nonlinearity and hysteresis in the actuator do not affect the measurement. The outcome of this is an improvement of the bending control of the cantilever and much higher scan speeds of up to 200 µm s-1.

  2. Frequency-Controls of Electromagnetic Multi-Beam Scanning by Metasurfaces

    PubMed Central

    Li, Yun Bo; Wan, Xiang; Cai, Ben Geng; Cheng, Qiang; Cui, Tie Jun

    2014-01-01

    We propose a method to control electromagnetic (EM) radiations by holographic metasurfaces, including to producing multi-beam scanning in one dimension (1D) and two dimensions (2D) with the change of frequency. The metasurfaces are composed of subwavelength metallic patches on grounded dielectric substrate. We present a combined theory of holography and leaky wave to realize the multi-beam radiations by exciting the surface interference patterns, which are generated by interference between the excitation source and required radiation waves. As the frequency changes, we show that the main lobes of EM radiation beams could accomplish 1D or 2D scans regularly by using the proposed holographic metasurfaces shaped with different interference patterns. This is the first time to realize 2D scans of antennas by changing the frequency. Full-wave simulations and experimental results validate the proposed theory and confirm the corresponding physical phenomena. PMID:25370447

  3. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial ... or other growth (mass) Cerebral atrophy (loss of brain tissue) ... with the hearing nerve Stroke or transient ischemic attack (TIA)

  4. Development of a computer-aided diagnostic scheme for detection of interval changes in successive whole-body bone scans

    SciTech Connect

    Shiraishi, Junji; Li Qiang; Appelbaum, Daniel; Pu Yonglin; Doi, Kunio

    2007-01-15

    Bone scintigraphy is the most frequent examination among various diagnostic nuclear medicine procedures. It is a well-established imaging modality for the diagnosis of osseous metastasis and for monitoring osseous tumor response to chemotherapy and radiation therapy. Although the sensitivity of bone scan examinations for detection of bone abnormalities has been considered to be relatively high, it is time consuming to identify multiple lesions such as bone metastases of prostate and breast cancers. In addition, it is very difficult to detect subtle interval changes between two successive abnormal bone scans, because of variations in patient conditions, the accumulation of radioisotopes during each examination, and the image quality of gamma cameras. Therefore, we developed a new computer-aided diagnostic (CAD) scheme for the detection of interval changes in successive whole-body bone scans by use of a temporal subtraction image which was obtained with a nonlinear image-warping technique. We carried out 58 pairs of successive bone scans in which each scan included both posterior and anterior views. We determined 107 'gold-standard' interval changes among the 58 pairs based on the consensus of three radiologists. Our computerized scheme consisted of seven steps, i.e., initial image density normalization on each image, image matching for the paired images, temporal subtraction by use of the nonlinear image-warping technique, initial detection of interval changes by use of temporal-subtraction images, image feature extraction of candidates of interval changes, rule-based tests by use of 16 image features for removing some false positives, and display of the computer output for identified interval changes. One hundred seven gold standard interval changes included 71 hot lesions (uptake was increased compared with the previous scan, or there was new uptake in the current scan) and 36 cold lesions (uptake was decreased or disappeared) for anterior and posterior views. The

  5. Development of a computer-aided diagnostic scheme for detection of interval changes in successive whole-body bone scans.

    PubMed

    Shiraishi, Junji; Li, Qiang; Appelbaum, Daniel; Pu, Yonglin; Doi, Kunio

    2007-01-01

    Bone scintigraphy is the most frequent examination among various diagnostic nuclear medicine procedures. It is a well-established imaging modality for the diagnosis of osseous metastasis and for monitoring osseous tumor response to chemotherapy and radiation therapy. Although the sensitivity of bone scan examinations for detection of bone abnormalities has been considered to be relatively high, it is time consuming to identify multiple lesions such as bone metastases of prostate and breast cancers. In addition, it is very difficult to detect subtle interval changes between two successive abnormal bone scans, because of variations in patient conditions, the accumulation of radioisotopes during each examination, and the image quality of gamma cameras. Therefore, we developed a new computer-aided diagnostic (CAD) scheme for the detection of interval changes in successive whole-body bone scans by use of a temporal subtraction image which was obtained with a nonlinear image-warping technique. We carried out 58 pairs of successive bone scans in which each scan included both posterior and anterior views. We determined 107 "gold-standard" interval changes among the 58 pairs based on the consensus of three radiologists. Our computerized scheme consisted of seven steps, i.e., initial image density normalization on each image, image matching for the paired images, temporal subtraction by use of the nonlinear image-warping technique, initial detection of interval changes by use of temporal-subtraction images, image feature extraction of candidates of interval changes, rule-based tests by use of 16 image features for removing some false positives, and display of the computer output for identified interval changes. One hundred seven gold standard interval changes included 71 hot lesions (uptake was increased compared with the previous scan, or there was new uptake in the current scan) and 36 cold lesions (uptake was decreased or disappeared) for anterior and posterior views. The

  6. COMSAC: Computational Methods for Stability and Control. Part 1

    NASA Technical Reports Server (NTRS)

    Fremaux, C. Michael (Compiler); Hall, Robert M. (Compiler)

    2004-01-01

    Work on stability and control included the following reports:Introductory Remarks; Introduction to Computational Methods for Stability and Control (COMSAC); Stability & Control Challenges for COMSAC: a NASA Langley Perspective; Emerging CFD Capabilities and Outlook A NASA Langley Perspective; The Role for Computational Fluid Dynamics for Stability and Control:Is it Time?; Northrop Grumman Perspective on COMSAC; Boeing Integrated Defense Systems Perspective on COMSAC; Computational Methods in Stability and Control:WPAFB Perspective; Perspective: Raytheon Aircraft Company; A Greybeard's View of the State of Aerodynamic Prediction; Computational Methods for Stability and Control: A Perspective; Boeing TacAir Stability and Control Issues for Computational Fluid Dynamics; NAVAIR S&C Issues for CFD; An S&C Perspective on CFD; Issues, Challenges & Payoffs: A Boeing User s Perspective on CFD for S&C; and Stability and Control in Computational Simulations for Conceptual and Preliminary Design: the Past, Today, and Future?

  7. The analysis of control trajectories using symbolic and database computing

    NASA Technical Reports Server (NTRS)

    Grossman, Robert

    1991-01-01

    The research broadly concerned the symbolic computation, mixed numeric-symbolic computation, and data base computation of trajectories of dynamical systems, especially control systems. It was determined that trees can be used to compute symbolically series which approximate solutions to differential equations.

  8. Computer Instructional Aids for Undergraduate Control Education. 1978 Edition.

    ERIC Educational Resources Information Center

    Volz, Richard A.; And Others

    This work represents the development of computer tools for undergraduate students. Emphasis is on automatic control theory using hybrid and digital computation. The routine calculations of control system analysis are presented as students would use them on the University of Michigan's central digital computer and the time-shared graphic terminals…

  9. Role of Extracranial Carotid Duplex and Computed Tomography Perfusion Scanning in Evaluating Perfusion Status of Pericarotid Stenting

    PubMed Central

    Lin, Chih-Ming; Chang, Yu-Jun; Liu, Chi-Kuang; Yu, Cheng-Sheng

    2016-01-01

    Carotid stenting is an effective treatment of choice in terms of treating ischemic stroke patients with concomitant carotid stenosis. Though computed tomography perfusion scan has been recognized as a standard tool to monitor/follow up this group of patients, not everyone could endure due to underlying medical illness. In contrast, carotid duplex is a noninvasive assessment tool and could track patient clinical condition in real time. In this study we found that “resistance index” of the carotid ultrasound could detect flow changes before and after the stenting procedure, thus having great capacity to replace the role of computed tomography perfusion exam. PMID:27051669

  10. Controlling data transfers from an origin compute node to a target compute node

    DOEpatents

    Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

    2011-06-21

    Methods, apparatus, and products are disclosed for controlling data transfers from an origin compute node to a target compute node that include: receiving, by an application messaging module on the target compute node, an indication of a data transfer from an origin compute node to the target compute node; and administering, by the application messaging module on the target compute node, the data transfer using one or more messaging primitives of a system messaging module in dependence upon the indication.

  11. Frequency scanning interferometry with nanometer precision using a vertical-cavity surface-emitting laser diode under scanning speed control

    NASA Astrophysics Data System (ADS)

    Kakuma, Seiichi

    2015-12-01

    Frequency scanning interferometry technique with a nanometer precision using a vertical-cavity surface-emitting laser diode (VCSEL) is presented. Since the frequency scanning of the VCSEL is linearized by the phase-locked-loop technique, the gradient of the interference fringe order can be precisely determined using linear least squares fitting. This enables a length measurement with a precision better than a quarter wavelength, and the absolute fringe number including the integer part at the atomic transition spectrum (rubidium-D2 line) is accurately determined. The validity of the method is demonstrated by excellent results of block gauge measurement with a root mean square error better than 5 nm.

  12. Computed tomography scanning can monitor the effects of soil medium on root system development: an example of salt stress in corn.

    PubMed

    Subramanian, Sowmyalakshmi; Han, Liwen; Dutilleul, Pierre; Smith, Donald L

    2015-01-01

    Seeds and young seedlings often encounter high soluble salt levels in the upmost soil layers, impeding vigorous growth by affecting root establishment. Computed tomography (CT) scanning used at low X-ray doses can help study root development in such conditions non-destructively, because plants are allowed to grow throughout the experiment. Using a high-resolution Toshiba XVision CT scanner, we studied corn (Zea mays L.) root growth under optimal and salt-stressed conditions in 3D and on a weekly basis over 3 weeks. Two groups of three corn plants were grown in the controlled environment of a growth chamber, in mid-sized plastic pots filled with sieved and autoclaved sand. Seedlings were subjected to first CT scanning 1 week after seed planting. Our main research objectives concerning root systems were: (i) to quantify structural complexity from fractal dimensions estimated on skeletal 3-D images built from CT scanning data; (ii) to measure growth from volumes and lengths and the derived relative rates and increments, after isolating primary and secondary roots from the soil medium in CT scanning data; and (iii) to assess differences in complexity and growth per week and over Weeks 1-3 for groups of corn plants. Differences between groups were present from Week 1; starting in Week 2 secondary roots were present and could be isolated, which refined the complexity and growth analyses of root systems. Besides expected Week main effects (P < 0.01 or 0.05), Week × Group interaction (P < 0.05 or 0.10), and Group main effects were observed. Graphical, quantitative, and statistical analyses of CT scanning data were thus completed at an unprecedented level, and provided new and important insights regarding root system development. Repeated CT scanning is the key to a better understanding of the establishment in the soil medium of crop plants such as corn and the assessment of salt stress effects on developing root systems, in complexity, volume, and length. PMID:25972876

  13. Computed tomography scanning can monitor the effects of soil medium on root system development: an example of salt stress in corn

    PubMed Central

    Subramanian, Sowmyalakshmi; Han, Liwen; Dutilleul, Pierre; Smith, Donald L.

    2015-01-01

    Seeds and young seedlings often encounter high soluble salt levels in the upmost soil layers, impeding vigorous growth by affecting root establishment. Computed tomography (CT) scanning used at low X-ray doses can help study root development in such conditions non-destructively, because plants are allowed to grow throughout the experiment. Using a high-resolution Toshiba XVision CT scanner, we studied corn (Zea mays L.) root growth under optimal and salt-stressed conditions in 3D and on a weekly basis over 3 weeks. Two groups of three corn plants were grown in the controlled environment of a growth chamber, in mid-sized plastic pots filled with sieved and autoclaved sand. Seedlings were subjected to first CT scanning 1 week after seed planting. Our main research objectives concerning root systems were: (i) to quantify structural complexity from fractal dimensions estimated on skeletal 3-D images built from CT scanning data; (ii) to measure growth from volumes and lengths and the derived relative rates and increments, after isolating primary and secondary roots from the soil medium in CT scanning data; and (iii) to assess differences in complexity and growth per week and over Weeks 1–3 for groups of corn plants. Differences between groups were present from Week 1; starting in Week 2 secondary roots were present and could be isolated, which refined the complexity and growth analyses of root systems. Besides expected Week main effects (P < 0.01 or 0.05), Week × Group interaction (P < 0.05 or 0.10), and Group main effects were observed. Graphical, quantitative, and statistical analyses of CT scanning data were thus completed at an unprecedented level, and provided new and important insights regarding root system development. Repeated CT scanning is the key to a better understanding of the establishment in the soil medium of crop plants such as corn and the assessment of salt stress effects on developing root systems, in complexity, volume, and length. PMID:25972876

  14. Adaptive AFM scan speed control for high aspect ratio fast structure tracking

    SciTech Connect

    Ahmad, Ahmad; Schuh, Andreas; Rangelow, Ivo W.

    2014-10-15

    Improved imaging rates in Atomic Force Microscopes (AFM) are of high interest for disciplines such as life sciences and failure analysis of semiconductor wafers, where the sample topology shows high aspect ratios. Also, fast imaging is necessary to cover a large surface under investigation in reasonable times. Since AFMs are composed of mechanical components, they are associated with comparably low resonance frequencies that undermine the effort to increase the acquisition rates. In particular, high and steep structures are difficult to follow, which causes the cantilever to temporarily loose contact to or crash into the sample. Here, we report on a novel approach that does not affect the scanner dynamics, but adapts the lateral scanning speed of the scanner. The controller monitors the control error signal and, only when necessary, decreases the scan speed to allow the z-piezo more time to react to changes in the sample's topography. In this case, the overall imaging rate can be significantly increased, because a general scan speed trade-off decision is not needed and smooth areas are scanned fast. In contrast to methods trying to increase the z-piezo bandwidth, our method is a comparably simple approach that can be easily adapted to standard systems.

  15. Reliable timing systems for computer controlled accelerators

    NASA Astrophysics Data System (ADS)

    Knott, Jürgen; Nettleton, Robert

    1986-06-01

    Over the past decade the use of computers has set new standards for control systems of accelerators with ever increasing complexity coupled with stringent reliability criteria. In fact, with very slow cycling machines or storage rings any erratic operation or timing pulse will cause the loss of precious particles and waste hours of time and effort of preparation. Thus, for the CERN linac and LEAR (Low Energy Antiproton Ring) timing system reliability becomes a crucial factor in the sense that all components must operate practically without fault for very long periods compared to the effective machine cycle. This has been achieved by careful selection of components and design well below thermal and electrical limits, using error detection and correction where possible, as well as developing "safe" decoding techniques for serial data trains. Further, consistent structuring had to be applied in order to obtain simple and flexible modular configurations with very few components on critical paths and to minimize the exchange of information to synchronize accelerators. In addition, this structuring allows the development of efficient strategies for on-line and off-line fault diagnostics. As a result, the timing system for Linac 2 has, so far, been operating without fault for three years, the one for LEAR more than one year since its final debugging.

  16. Computer-controlled endoscopic performance assessment system.

    PubMed

    Hanna, G B; Drew, T; Clinch, P; Hunter, B; Cuschieri, A

    1998-07-01

    We have devised an advanced computer-controlled system (ADEPT) for the objective evaluation of endoscopic task performance. The system's hardware consists of a dual gimbal mechanism that accepts a variety of 5.0-mm standard endoscopic instruments for manipulation in a precisely mapped and enclosed work space. The target object consists of a sprung base plate incorporating various tasks. It is covered by a sprung perforated transparent top plate that has to be moved and held in the correct position by the operator to gain access to the various tasks. Standard video endoscope equipment provides the visual interface between the operator and the target-instrument field. Different target modules can be used, and the level of task difficulty can be adjusted by varying the manipulation, elevation, and azimuth angles. The system's software is designed to (a) prompt the surgeon with the information necessary to perform the task, (b) collect and collate data on performance during execution of specified tasks, and (c) save the data for future analysis. The system was alpha and beta tested to ensure that all functions operated correctly. PMID:9632879

  17. Computer control of a microgravity mammalian cell bioreactor

    NASA Technical Reports Server (NTRS)

    Hall, William A.

    1987-01-01

    The initial steps taken in developing a completely menu driven and totally automated computer control system for a bioreactor are discussed. This bioreactor is an electro-mechanical cell growth system cell requiring vigorous control of slowly changing parameters, many of which are so dynamically interactive that computer control is a necessity. The process computer will have two main functions. First, it will provide continuous environmental control utilizing low signal level transducers as inputs and high powered control devices such as solenoids and motors as outputs. Secondly, it will provide continuous environmental monitoring, including mass data storage and periodic data dumps to a supervisory computer.

  18. Robotic Automation in Computer Controlled Polishing

    NASA Astrophysics Data System (ADS)

    Walker, D. D.; Yu, G.; Bibby, M.; Dunn, C.; Li, H.; Wu, Y.; Zheng, X.; Zhang, P.

    2016-02-01

    We first present a Case Study - the manufacture of 1.4 m prototype mirror-segments for the European Extremely Large Telescope, undertaken by the National Facility for Ultra Precision Surfaces, at the OpTIC facility operated by Glyndwr University. Scale-up to serial-manufacture demands delivery of a 1.4 m off-axis aspheric hexagonal segment with surface precision < 10 nm RMS every four days, compared with a typical year or more for an one-off part. This requires a radically-new approach to large optics fabrication, which will inevitably propagate into wider industrial optics. We report on how these ambitious requirements have stimulated an investigation into the synergy between robots and computer numerically controlled ('CNC') polishing machines for optical fabrication. The objective was not to assess which is superior. Rather, it was to understand for the first time their complementary properties, leading us to operate them together as a unit, integrated in hardware and software. Three key areas are reported. First is the novel use of robots to automate currently-manual operations on CNC polishing machines, to improve work-throughput, mitigate risk of damage to parts, and reduce dependence on highly-skilled staff. Second is the use of robots to pre-process surfaces prior to CNC polishing, to reduce total process time. The third draws the threads together, describing our vision of the automated manufacturing cell, where the operator interacts at cell rather than machine level. This promises to deliver a step-change in end-to-end manufacturing times and costs, compared with either platform used on its own or, indeed, the state-of-the-art used elsewhere.

  19. Computer-aided design of flight control systems

    NASA Technical Reports Server (NTRS)

    Stengel, Robert F.; Sircar, Subrata

    1991-01-01

    A computer program is presented for facilitating the development and assessment of flight control systems, and application to a control design is discussed. The program is a computer-aided control-system design program based on direct digital synthesis of a proportional-integral-filter controller with scheduled linear-quadratic-Gaussian gains and command generator tracking of pilot inputs. The FlightCAD system concentrates on aircraft dynamics, flight-control systems, stability and performance, and has practical engineering applications.

  20. Just Scan It!-Weapon Reconstruction in Computed Tomography on Historical and Current Swiss Military Guns.

    PubMed

    Franckenberg, Sabine; Binder, Thomas; Bolliger, Stephan; Thali, Michael J; Ross, Steffen G

    2016-09-01

    Cross-sectional imaging, such as computed tomography, has been increasingly implemented in both historic and recent postmortem forensic investigations. It aids in determining cause and manner of death as well as in correlating injuries to possible weapons. This study illuminates the feasibility of reconstructing guns in computed tomography and gives a distinct overview of historic and recent Swiss Army guns. PMID:27454744

  1. SCADA computer sytem controls major Saudi Aramco crude oil pipeline

    SciTech Connect

    Dempsey, J.; Al-Habib, R.

    1996-12-31

    A replacement Supervisory Control and Data Acquisition (SCADA) computer system which monitors and controls two 1,100 kilometer pipelines and eleven associated pump stations is described. The SCADA system was designed to meet two objectives: (1) decentralize the overall control system and provide a distributed control system capable of regulatory control at each pump and pressure reducing station, and (2) provide system wide monitoring and supervisory control function during normal operations at the crude oil terminal. The SCADA computer system hardware (host computers and consoles), software modules, and applications are overviewed. A data flow diagram and a hardware configuration diagram are provided. 3 figs.

  2. Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

    PubMed Central

    Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin

    2016-01-01

    Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. Results All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. Conclusions The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken. PMID:27226958

  3. Image processing of computed tomography scan data for automated structure identification and stress analysis

    SciTech Connect

    Meagher, J.M.

    1988-01-01

    This research investigates a non-invasive method to determine trabecular architecture, and its incorporation into FEM automatically generated from CT scan data. Part of the image processing involves a general method to remove beam hardening error from CT scan data without requiring the original projection data. A FEM of a canine femur is used to investigate bone stress-morphology relationships, and their sensitivity to load distribution, beam hardening errors, and anisotropic modeling of bone. The method to identify bone uses sequential application of edge gradient masks. CT span predictions were verified using histologic sections. The area fraction of bone and trabecular orientation were determined within 10% and 15 degrees when the pixel size was smaller than the intratrabecular spacing. Beam hardening is removed from CT scan data using simulated projections through the uncorrected image. Linearity of the reconstruction algorithm is used to add reconstructed projection corrections to the uncorrected image. The error in theoretical attenuation for a test phantom decreased from 30% to 5% with virtual elimination of the streak artifact. The image improvement equals that achieved with corrections based on the original projection data when all beam hardening occurs within the reconstruction space.

  4. Bilateral control-based compensation for rotation in imaging in scan imaging systems

    NASA Astrophysics Data System (ADS)

    Tian, Dapeng; Wang, Yutang; Wang, Fuchao; Zhang, Yupeng

    2015-12-01

    Scan imaging systems rely on the rotation of a mirror to scan an image. The rotation in the resulting image must be compensated to prevent information loss. Satisfactory performance of an imaging system is difficult to achieve when employing the methods of mechanical transmission and unilateral tracking control, especially when the system suffers from nonlinear factors, disturbances, and dynamic uncertainties. This paper proposes a compensation method based on bilateral control derived from the field of haptic robots. A two-loop disturbance observer was designed to guarantee that the dynamic characteristics of the motor are close to those of the nominal model. The controllers were designed on the basis of the small gain theorem. Experiments were conducted for a comparison with the traditional unilateral control-based compensation. The comparison showed a reduction of 99.83% in the L2 norm of error, which validates the method. The proposed method improves the accuracy of compensation for rotation in imaging, and demonstrates that bilateral control has feasibility for application in various fields, including photogrammetry.

  5. Using a Computer to Control Stuttering.

    ERIC Educational Resources Information Center

    Williams, John

    1983-01-01

    A computer was used to help a man who stuttered severely most of his 37 years. The criterion based treatment used a specifically designed program (Speech Flow Acquisition Program) to train him to speak smoothly. (SEW)

  6. BioSCAN: a network sharable computational resource for searching biosequence databases.

    PubMed

    Singh, R K; Hoffman, D L; Tell, S G; White, C T

    1996-06-01

    We describe a network sharable, interactive computational tool for rapid and sensitive search and analysis of biomolecular sequence databases such as GenBank, GenPept, Protein Identification Resource, and SWISS-PROT. The resource is accessible via the World Wide Web using popular client software such as Mosaic and Netscape. The client software is freely available on a number of computing platforms including Macintosh, IBM-PC, and Unix workstations. PMID:8872387

  7. Comparison of Control Algorithms for a MEMS-based Adaptive Optics Scanning Laser Ophthalmoscope

    PubMed Central

    Li, Kaccie Y.; Mishra, Sandipan; Tiruveedhula, Pavan; Roorda, Austin

    2010-01-01

    We compared four algorithms for controlling a MEMS deformable mirror of an adaptive optics (AO) scanning laser ophthalmoscope. Interferometer measurements of the static nonlinear response of the deformable mirror were used to form an equivalent linear model of the AO system so that the classic integrator plus wavefront reconstructor type controller can be implemented. The algorithms differ only in the design of the wavefront reconstructor. The comparisons were made for two eyes (two individuals) via a series of imaging sessions. All four controllers performed similarly according to estimated residual wavefront error not reflecting the actual image quality observed. A metric based on mean image intensity did consistently reflect the qualitative observations of retinal image quality. Based on this metric, the controller most effective for suppressing the least significant modes of the deformable mirror performed the best. PMID:20454552

  8. Automatic exposure control for a slot scanning full field digital mammography system

    SciTech Connect

    Elbakri, Idris A.; Lakshminarayanan, A.V.; Tesic, Mike M.

    2005-09-15

    Automatic exposure control (AEC) is an important feature in mammography. It enables consistently optimal image exposure despite variations in tissue density and thickness, and user skill level. Full field digital mammography systems cannot employ conventional AEC methods because digital receptors fully absorb the x-ray beam. In this paper we describe an AEC procedure for slot scanning mammography. With slot scanning detectors, our approach uses a fast low-resolution and low-exposure prescan to acquire an image of the breast. Tube potential depends on breast thickness, and the prescan histogram provides the necessary information to calculate the required tube current. We validate our approach with simulated prescan images and phantom measurements. We achieve accurate exposure tracking with thickness and density, and expect this method of AEC to reduce retakes and improve workflow.

  9. Human hand-transmitted vibration measurements on pedestrian controlled tractor operators by a laser scanning vibrometer.

    PubMed

    Deboli, R; Miccoli, G; Rossi, G L

    1999-06-01

    A first application of a new measurement technique to detect vibration transmitted to the human body in working conditions is presented. The technique is based on the use of a laser scanning vibrometer. It was previously developed, analysed and tested using laboratory test benches with electrodynamical exciters, and comparisons with traditional measurement techniques based on accelerometers were made. First, results of tests performed using a real machine generating vibration are illustrated. The machine used is a pedestrian-controlled tractor working in a fixed position. Reference measurements by using the accelerometer have been simultaneously performed while scanning the hand surface by the laser-based measurement system. Results achieved by means of both measurement techniques have been processed, analysed, compared and used to calculate transmissibility maps of the hands of three subjects. PMID:10340028

  10. Computer Control For Gas/Tungsten-Arc Welding

    NASA Technical Reports Server (NTRS)

    Andersen, Kristinn; Springfield, James F.; Barnett, Robert J.; Cook, George E.

    1994-01-01

    Prototype computer-based feedback control system developed for use in gas/tungsten arc welding. Beyond improving welding technician's moment-to-moment general control of welding process, control system designed to assist technician in selecting appropriate welding-process parameters, and provide better automatic voltage control. Modular for ease of reconfiguration and upgrading. Modularity also reflected in software. Includes rack-mounted computer, based on VME bus, containing Intel 80286 and 80386 processors.

  11. Immediate Implant Placement in Anterior Aesthetic Region and Assessment using Cone-Beam Computed Tomography Scan Technology

    PubMed Central

    Joshi, Vaibhav; Gupta, Shalini

    2015-01-01

    The esthetics and functional integrity of the periodontal tissues may be compromised by the dental loss. Dental implants have become an additional tool in the armamentarium of treatment options to offer the patient for the replacement of a missing tooth or teeth. Diagnosis and treatment planning is the key factors in achieving the successful outcome after placing and restoring implants placed immediately after tooth extraction. The introduction of cone-beam computed tomography (CBCT) for the maxillofacial region provides opportunities for dental practitioners to request multiplanar imaging. This case report demonstrates the use of CBCT scan technology in immediate implant placement in the maxillary anterior teeth region. PMID:26668494

  12. Dwell time calculation for computer controlled large tool

    NASA Astrophysics Data System (ADS)

    Fan, Bin; Burge, James H.; Martin, Hubert; Zeng, Zhige; Li, Xiaojin; Zhou, Jiabin

    2012-09-01

    The Computer-controlled Large-tool such as the stressed-lap which firstly developed in the Steward Observatory Mirror Lab (SOML) [1]and the Computer controlled active lap which developed in the IOE (Institute of Optics and Electronics, Chinese Academy of Science), those large tools are controlled by computer to manufacturing large optics, especially for grinding with loose abrasive and polishing with slurry. Comparing the fixed orbital lap, computer-controlled largetool can bend its lap surface timely to match the local sub-aperture, so it always strike the high area preferentially, due to its large diameter , computer-controlled large-tool possess highly remove efficiency and generate less middle-frequency and high-frequency errors comparing some small tools such as computer controlled optical surface (CCOS), but on the other hand how to calculate the dwell time for those computer-controlled large-tool becomes a challenge comparing those small tools. Based on the mathematical removal equation for computer controlled active lap we have none negative least square algorithm to calculate the dwell time, after the simulation, a optimized algorithm based on none negative least square is provided, the dwell time calculated by this optimized algorithm meet the wanted removal volume with little residual errors.

  13. Stimulus Control with Computer Assisted Learning

    ERIC Educational Resources Information Center

    Navarro, Jose I.; Marchena, Esperanza; Alcalde, Concepcion; Ruiz, Gonzalo

    2004-01-01

    Computer Assisted Learning (CAL) has been shown to be an efficient learning-teaching procedure. Although there is an extensive educational software tradition using CAL approaches, few of them have demonstrated a better student performance than standard drill and practice methods. The purpose of this study was (a) to evaluate the effectiveness of…

  14. Novel method for controlled wetting of materials in the environmental scanning electron microscope.

    PubMed

    Jansson, Anna; Nafari, Alexandra; Sanz-Velasco, Anke; Svensson, Krister; Gustafsson, Stefan; Hermansson, Anne-Marie; Olsson, Eva

    2013-02-01

    Environmental scanning electron microscopy has been extensively used for studying the wetting properties of different materials. For some types of investigation, however, the traditional ways of conducting in situ dynamic wetting experiments do not offer sufficient control over the wetting process. Here, we present a novel method for controlled wetting of materials in the environmental scanning electron microscope (ESEM). It offers improved control of the point of interaction between the water and the specimen and renders it more accessible for imaging. It also enables the study of water transport through a material by direct imaging. The method is based on the use of a piezo-driven nanomanipulator to bring a specimen in contact with a water reservoir in the ESEM chamber. The water reservoir is established by local condensation on a Peltier-cooled surface. A fixture was designed to make the experimental setup compatible with the standard Peltier cooling stage of the microscope. The developed technique was successfully applied to individual cellulose fibers, and the absorption and transport of water by individual cellulose fibers were imaged. PMID:23332145

  15. Modification and Development of a Control Mechanism for the Scanning Microwave Limb Sounder

    NASA Technical Reports Server (NTRS)

    Greene, Zach

    2011-01-01

    The scanning microwave limb sounder (SMLS) is the latest instrument to probe the Earth's atmosphere to come out of the Microwave Limb Sounder (MLS) team. Once deployed to the upper stratosphere, it will use microwave detection to measure geo-atmospheric variables such as temperature, pressure, and chemical composition. In addition to previous missions that used vertical limb scans to observe altitudinal variations, the SMLS will rotate laterally allowing it to establish two-dimensional variable dependencies with a single run. A program was originated by a previous intern that will automatically control the movement of the two rotational axes along with a switching mirror and chopper once the instrument is in flight. However, it lacked the code essential to control system's ability to function fully and reliably. By modifying and rewriting parts of the code I sought to have a finished ready-for-flight control system that would be easy to navigate. Three of the major alterations I made including instituting a gyroscope, implementing a restart button, and instigating the automatic creation of a file log with each run to record the position and orientation of the SMLS.

  16. A High Precision Scanning Control System For A VUV Fourier Transform Spectrometer

    SciTech Connect

    De Oliveira, N.; Nahon, L.; Polack, F.; Joyeux, D.; Phalippou, D.; Rodier, J. C.; Vervloeet, M.

    2007-01-19

    A VUV Fourier transform spectrometer based on a wavefront division interferometer has been built. Our ultimate goal is to provide a high resolution absorption spectrometer in the 140 - 40 nm range using the new third generation French synchrotron source Soleil as the background continuum. Here, we present the design and latest performance of the instrument scanning control system. It is based on multiple reflections of a monomode, frequency-stabilized HeNe laser between two plane mirrors allowing the required sensitivity on the displacement of the interferometer mobile arm. The experimental results on the sampling precision show an rms error below 5 nm for a travel length of 7.5 mm.

  17. Serial cranial computed-tomography scans in children with leukemia given two different forms of central nervous system therapy

    SciTech Connect

    Ochs, J.J.; Parvey, L.S.; Whitaker, J.N.; Bowman, W.P.; Ch'ien, L.; Campbell, M.; Coburn, T.

    1983-12-01

    Cranial computed tomography (CT) was used to estimate the frequency and permanence of brain abnormalities in 108 consecutive children with acute lymphoblastic leukemia (ALL). Fifty-five patients received cranial irradiation (1,800 rad) with intrathecal methotrexate (RT group) and 53 patients received intravenous and intrathecal methotrexate without irradiation (IVIT group). Continuation treatment included sequential drug pairs for the RT group and periodic IVIT methotrexate for the other group. After 12 to 24 months of serial evaluation, five (9%) of the 55 patients in the RT group have had CT scan abnormalities, compared to 10 (19%) of 52 in the IVIT group (p . 0.171). Fourteen of the 15 patients with CT scan abnormalities had focal or diffuse white-matter hypodensity; these have reverted to normal in most cases, reflecting a dynamic process. While such CT findings are of concern and may be an early indicator of central nervous system toxicity, this remains to be proven. Therapy should not be altered on the basis of abnormal CT scans alone but in the context of the entire clinical situation.

  18. Image reconstruction based on total-variation minimization and alternating direction method in linear scan computed tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Han-Ming; Wang, Lin-Yuan; Yan, Bin; Li, Lei; Xi, Xiao-Qi; Lu, Li-Zhong

    2013-07-01

    Linear scan computed tomography (LCT) is of great benefit to online industrial scanning and security inspection due to its characteristics of straight-line source trajectory and high scanning speed. However, in practical applications of LCT, there are challenges to image reconstruction due to limited-angle and insufficient data. In this paper, a new reconstruction algorithm based on total-variation (TV) minimization is developed to reconstruct images from limited-angle and insufficient data in LCT. The main idea of our approach is to reformulate a TV problem as a linear equality constrained problem where the objective function is separable, and then minimize its augmented Lagrangian function by using alternating direction method (ADM) to solve subproblems. The proposed method is robust and efficient in the task of reconstruction by showing the convergence of ADM. The numerical simulations and real data reconstructions show that the proposed reconstruction method brings reasonable performance and outperforms some previous ones when applied to an LCT imaging problem.

  19. Towards practical control design using neural computation

    NASA Technical Reports Server (NTRS)

    Troudet, Terry; Garg, Sanjay; Mattern, Duane; Merrill, Walter

    1991-01-01

    The objective is to develop neural network based control design techniques which address the issue of performance/control effort tradeoff. Additionally, the control design needs to address the important issue if achieving adequate performance in the presence of actuator nonlinearities such as position and rate limits. These issues are discussed using the example of aircraft flight control. Given a set of pilot input commands, a feedforward net is trained to control the vehicle within the constraints imposed by the actuators. This is achieved by minimizing an objective function which is the sum of the tracking errors, control input rates and control input deflections. A tradeoff between tracking performance and control smoothness is obtained by varying, adaptively, the weights of the objective function. The neurocontroller performance is evaluated in the presence of actuator dynamics using a simulation of the vehicle. Appropriate selection of the different weights in the objective function resulted in the good tracking of the pilot commands and smooth neurocontrol. An extension of the neurocontroller design approach is proposed to enhance its practicality.

  20. Comparing algorithms for automated vessel segmentation in computed tomography scans of the lung: the VESSEL12 study.

    PubMed

    Rudyanto, Rina D; Kerkstra, Sjoerd; van Rikxoort, Eva M; Fetita, Catalin; Brillet, Pierre-Yves; Lefevre, Christophe; Xue, Wenzhe; Zhu, Xiangjun; Liang, Jianming; Öksüz, Ilkay; Ünay, Devrim; Kadipaşaoğlu, Kamuran; Estépar, Raúl San José; Ross, James C; Washko, George R; Prieto, Juan-Carlos; Hoyos, Marcela Hernández; Orkisz, Maciej; Meine, Hans; Hüllebrand, Markus; Stöcker, Christina; Mir, Fernando Lopez; Naranjo, Valery; Villanueva, Eliseo; Staring, Marius; Xiao, Changyan; Stoel, Berend C; Fabijanska, Anna; Smistad, Erik; Elster, Anne C; Lindseth, Frank; Foruzan, Amir Hossein; Kiros, Ryan; Popuri, Karteek; Cobzas, Dana; Jimenez-Carretero, Daniel; Santos, Andres; Ledesma-Carbayo, Maria J; Helmberger, Michael; Urschler, Martin; Pienn, Michael; Bosboom, Dennis G H; Campo, Arantza; Prokop, Mathias; de Jong, Pim A; Ortiz-de-Solorzano, Carlos; Muñoz-Barrutia, Arrate; van Ginneken, Bram

    2014-10-01

    The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of different algorithms to identify vessels in thoracic computed tomography (CT) scans. Vessel segmentation is fundamental in computer aided processing of data generated by 3D imaging modalities. As manual vessel segmentation is prohibitively time consuming, any real world application requires some form of automation. Several approaches exist for automated vessel segmentation, but judging their relative merits is difficult due to a lack of standardized evaluation. We present an annotated reference dataset containing 20 CT scans and propose nine categories to perform a comprehensive evaluation of vessel segmentation algorithms from both academia and industry. Twenty algorithms participated in the VESSEL12 challenge, held at International Symposium on Biomedical Imaging (ISBI) 2012. All results have been published at the VESSEL12 website http://vessel12.grand-challenge.org. The challenge remains ongoing and open to new participants. Our three contributions are: (1) an annotated reference dataset available online for evaluation of new algorithms; (2) a quantitative scoring system for objective comparison of algorithms; and (3) performance analysis of the strengths and weaknesses of the various vessel segmentation methods in the presence of various lung diseases. PMID:25113321

  1. Feasibility study of in-process weld quality control by means of scanning laser profilometry

    NASA Astrophysics Data System (ADS)

    Jezeršek, Matija; Polajnar, Ivan; Diaci, Janez

    2007-06-01

    We have developed a scanning laser system based on the optical triangulation principle for the shape measurement of fusion weld surfaces. The system integrates a triangulation module consisting of a laser line projector and a digital video camera with a mechanical scanning stage and an industrial computer. The system is small and rugged, suitable for application in industrial environment. The system can sample a weld surface at a rate of up to 30 profiles per second achieving 0.1mm accuracy. Software was developed which analyses the captured weld surface shape in real time determining the characteristic shape parameters (length, width, height, cross section, volume, starting position,...) which are then used for automated classification of the welds into acceptable and unacceptable. The software also detects surface defects such as undercutting, holes or melt splash, etc. The system has been tested in a robotized welding cell for automotive parts in an industrial production facility. Weld classification obtained by the system was compared to an independent classification determined by a trained weld inspector on the basis of visual inspection and to another one determined on the basis of metallographic analysis of the weld. Using the metallographic based classification as the reference we find that the developed weld inspection system can achieve better classification reliability than a trained visual weld inspector.

  2. Computationally Efficient Steady-State Solution of the Bloch Equations for Rapid Sinusoidal Scans Based on Fourier Expansion in Harmonics of the Scan Frequency

    PubMed Central

    Tseitlin, Mark; Eaton, Gareth R.; Eaton, Sandra S.

    2014-01-01

    Rapid-scan EPR has been shown to improve the signal-to-noise ratio relative to conventional continuous wave spectroscopy. Equations are derived for the steady-state solution to the Bloch equations as a Fourier expansion in the harmonics of the scan frequency. This simulation method is about two orders of magnitude faster than time-domain numerical integration. PMID:24678142

  3. Scalable quantum computation via local control of only two qubits

    SciTech Connect

    Burgarth, Daniel; Maruyama, Koji; Murphy, Michael; Montangero, Simone; Calarco, Tommaso; Nori, Franco; Plenio, Martin B.

    2010-04-15

    We apply quantum control techniques to a long spin chain by acting only on two qubits at one of its ends, thereby implementing universal quantum computation by a combination of quantum gates on these qubits and indirect swap operations across the chain. It is shown that the control sequences can be computed and implemented efficiently. We discuss the application of these ideas to physical systems such as superconducting qubits in which full control of long chains is challenging.

  4. Controlled-Resonant Surface Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

    SciTech Connect

    Lorenz, Matthias; Ovchinnikova, Olga S; Kertesz, Vilmos; Van Berkel, Gary J

    2014-01-01

    This paper reports on the advancement of a controlled-resonance surface tapping-mode single capillary liquid junction extraction/ESI emitter for mass spectrometry imaging. The basic instrumental setup and the general operation of the system were discussed and optimized performance metrics were presented. The ability to spot sample, lane scan and chemically image in an automated and controlled fashion were demonstrated. Rapid, automated spot sampling was demonstrated for a variety of compound types including the cationic dye basic blue 7, the oligosaccharide cellopentaose, and the protein equine heart cytochrome c. The system was used for lane scanning and chemical imaging of the cationic dye crystal violet in inked lines on glass and for lipid distributions in mouse brain thin tissue sections. Imaging of the lipids in mouse brain tissue under optimized conditions provided a spatial resolution of approximately 35 m based on the ability to distinguish between features observed both in the optical and mass spectral chemical images. The sampling spatial resolution of this system was comparable to the best resolution that has been reported for other types of atmospheric pressure liquid extraction-based surface sampling/ionization techniques used for mass spectrometry imaging.

  5. Radiation Dose to the Lens of the Eye from Computed Tomography Scans of the Head

    NASA Astrophysics Data System (ADS)

    Januzis, Natalie Ann

    While it is well known that exposure to radiation can result in cataract formation, questions still remain about the presence of a dose threshold in radiation cataractogenesis. Since the exposure history from diagnostic CT exams is well documented in a patient's medical record, the population of patients chronically exposed to radiation from head CT exams may be an interesting area to explore for further research in this area. However, there are some challenges in estimating lens dose from head CT exams. An accurate lens dosimetry model would have to account for differences in imaging protocols, differences in head size, and the use of any dose reduction methods. The overall objective of this dissertation was to develop a comprehensive method to estimate radiation dose to the lens of the eye for patients receiving CT scans of the head. This research is comprised of a physics component, in which a lens dosimetry model was derived for head CT, and a clinical component, which involved the application of that dosimetry model to patient data. The physics component includes experiments related to the physical measurement of the radiation dose to the lens by various types of dosimeters placed within anthropomorphic phantoms. These dosimeters include high-sensitivity MOSFETs, TLDs, and radiochromic film. The six anthropomorphic phantoms used in these experiments range in age from newborn to adult. First, the lens dose from five clinically relevant head CT protocols was measured in the anthropomorphic phantoms with MOSFET dosimeters on two state-of-the-art CT scanners. The volume CT dose index (CTDIvol), which is a standard CT output index, was compared to the measured lens doses. Phantom age-specific CTDIvol-to-lens dose conversion factors were derived using linear regression analysis. Since head size can vary among individuals of the same age, a method was derived to estimate the CTDIvol-to-lens dose conversion factor using the effective head diameter. These conversion

  6. Radiation Dose to the Lens of the Eye from Computed Tomography Scans of the Head

    NASA Astrophysics Data System (ADS)

    Januzis, Natalie Ann

    While it is well known that exposure to radiation can result in cataract formation, questions still remain about the presence of a dose threshold in radiation cataractogenesis. Since the exposure history from diagnostic CT exams is well documented in a patient's medical record, the population of patients chronically exposed to radiation from head CT exams may be an interesting area to explore for further research in this area. However, there are some challenges in estimating lens dose from head CT exams. An accurate lens dosimetry model would have to account for differences in imaging protocols, differences in head size, and the use of any dose reduction methods. The overall objective of this dissertation was to develop a comprehensive method to estimate radiation dose to the lens of the eye for patients receiving CT scans of the head. This research is comprised of a physics component, in which a lens dosimetry model was derived for head CT, and a clinical component, which involved the application of that dosimetry model to patient data. The physics component includes experiments related to the physical measurement of the radiation dose to the lens by various types of dosimeters placed within anthropomorphic phantoms. These dosimeters include high-sensitivity MOSFETs, TLDs, and radiochromic film. The six anthropomorphic phantoms used in these experiments range in age from newborn to adult. First, the lens dose from five clinically relevant head CT protocols was measured in the anthropomorphic phantoms with MOSFET dosimeters on two state-of-the-art CT scanners. The volume CT dose index (CTDIvol), which is a standard CT output index, was compared to the measured lens doses. Phantom age-specific CTDIvol-to-lens dose conversion factors were derived using linear regression analysis. Since head size can vary among individuals of the same age, a method was derived to estimate the CTDIvol-to-lens dose conversion factor using the effective head diameter. These conversion

  7. Ex Vivo Anatomical Characterization of Handsewn or Stapled Jejunocecal Anastomosis in Horses by Computed Tomography Scan

    PubMed Central

    Giusto, Gessica; Iotti, Bryan; Sammartano, Federica; Valazza, Alberto; Gandini, Marco

    2014-01-01

    The aim of this study is to compare handsewn and stapled jejunocecal anastomosis with different stomal lengths in terms of anatomical differences. Group 1 underwent a two-layer handsewn jejunocecal side-to-side anastomosis (HS); Group 2 received a stapled jejunocecal side-to-side anastomosis (GIA). Each group was divided into two subgroups (HS80 and HS100, GIA80 and GIA100). Specimens were inflated and CT scanned. The stomal/jejunal area ratio and blind end pouch volume/area were measured and compared. Effective length of the stoma was measured and compared with the initial length. Stomal/jejunal area ratio was 1.1 for both 80 techniques, 1.6 for the GIA100, and 1.9 for the HS100 technique. Both HS and GIA techniques produced a blind end pouch and exhibited a mean increase of the final stomal length ranging from 6 to 11% greater than the original stomal length. All techniques will exhibit a length increase of the final stomal length compared to the intended stomal length, with a consequent increase in stomal area. Stapled techniques consistently produced a large distal blind end pouch. Length of a jejunocecal anastomosis should be selected in accordance with the diameter of afferent jejunum, and the 80 mm stomal length could be deemed sufficient in horses. PMID:26464922

  8. Role of optical computers in aeronautical control applications

    NASA Technical Reports Server (NTRS)

    Baumbick, R. J.

    1981-01-01

    The role that optical computers play in aircraft control is determined. The optical computer has the potential high speed capability required, especially for matrix/matrix operations. The optical computer also has the potential for handling nonlinear simulations in real time. They are also more compatible with fiber optic signal transmission. Optics also permit the use of passive sensors to measure process variables. No electrical energy need be supplied to the sensor. Complex interfacing between optical sensors and the optical computer is avoided if the optical sensor outputs can be directly processed by the optical computer.

  9. Prospects for titanium alloy comparison control by electron beam scan frequency manipulation

    SciTech Connect

    Powell, A.; Pal, U.; Avyle, J.V.D.; Damkroger, B.

    1996-12-31

    Using mathematical modelling, the authors evaluate the prospects for using beam spot size and scan frequency to control titanium-aluminum alloy composition in electron beam melting and refining. Composition control is evaluated in terms of attainable steady-state extremes of composition, and the time scales required to change hearth and mold composition between those extremes. Mathematical models predict spot size-evaporation and frequency-evaporation relationships by simulating heat transfer in the surface of the melt, and predict overall composition change using simplifying assumptions about the fluid flow field in a melting hearth. Corroborating experiments were run on the electron beam furnace at Sandia National Laboratories in order to verify predicted relationships between frequency and evaporation and to calculate activity coefficients of aluminum and vanadium in titanium.

  10. Controller for computer control of brushless dc motors. [automobile engines

    NASA Technical Reports Server (NTRS)

    Hieda, L. S. (Inventor)

    1981-01-01

    A motor speed and torque controller for brushless d.c. motors provides an unusually smooth torque control arrangement. The controller provides a means for controlling a current waveform in each winding of a brushless dc motor by synchronization of an excitation pulse train from a programmable oscillator. Sensing of torque for synchronization is provided by a light beam chopper mounted on the motor rotor shaft. Speed and duty cycle are independently controlled by controlling the frequency and pulse width output of the programmable oscillator. A means is also provided so that current transitions from one motor winding to another is effected without abrupt changes in output torque.

  11. Emergency Flight Control Using Computer-Controlled Thrust

    NASA Technical Reports Server (NTRS)

    Burcham, Frank W., Jr.; Fullerton, C. Gordon; Stewart, James F.; Gilyard, Glenn B.; Conley, Joseph A.

    1995-01-01

    Propulsion Controlled Aircraft (PCA) systems are digital electronic control systems undergoing development to provide limited maneuvering ability through variations of individual engine thrusts in multiple-engine airplanes. Provide landing capability when control surfaces inoperable. Incorporated on existing and future airplanes that include digital engine controls, digital flight controls, and digital data buses, adding no weight for additional hardware to airplane. Possible to handle total failure of hydraulic system, depending on how surfaces respond to loss of hydraulic pressure, and broken control cables or linkages. Future airplanes incorporate data from Global Positioning System for guidance to any suitable emergency runway in world.

  12. Registration of central paths and colonic polyps between supine and prone scans in computed tomography colonography: Pilot study

    SciTech Connect

    Li Ping; Napel, Sandy; Acar, Burak; Paik, David S.; Jeffrey, R. Brooke Jr.; Beaulieu, Christopher F.

    2004-10-01

    Computed tomography colonography (CTC) is a minimally invasive method that allows the evaluation of the colon wall from CT sections of the abdomen/pelvis. The primary goal of CTC is to detect colonic polyps, precursors to colorectal cancer. Because imperfect cleansing and distension can cause portions of the colon wall to be collapsed, covered with water, and/or covered with retained stool, patients are scanned in both prone and supine positions. We believe that both reading efficiency and computer aided detection (CAD) of CTC images can be improved by accurate registration of data from the supine and prone positions. We developed a two-stage approach that first registers the colonic central paths using a heuristic and automated algorithm and then matches polyps or polyp candidates (CAD hits) by a statistical approach. We evaluated the registration algorithm on 24 patient cases. After path registration, the mean misalignment distance between prone and supine identical anatomic landmarks was reduced from 47.08 to 12.66 mm, a 73% improvement. The polyp registration algorithm was specifically evaluated using eight patient cases for which radiologists identified polyps separately for both supine and prone data sets, and then manually registered corresponding pairs. The algorithm correctly matched 78% of these pairs without user input. The algorithm was also applied to the 30 highest-scoring CAD hits in the prone and supine scans and showed a success rate of 50% in automatically registering corresponding polyp pairs. Finally, we computed the average number of CAD hits that need to be manually compared in order to find the correct matches among the top 30 CAD hits. With polyp registration, the average number of comparisons was 1.78 per polyp, as opposed to 4.28 comparisons without polyp registration.

  13. Universal computer control system (UCCS) for space telerobots

    NASA Technical Reports Server (NTRS)

    Bejczy, Antal K.; Szakaly, Zoltan

    1987-01-01

    A universal computer control system (UCCS) is under development for all motor elements of a space telerobot. The basic hardware architecture and software design of UCCS are described, together with the rich motor sensing, control, and self-test capabilities of this all-computerized motor control system. UCCS is integrated into a multibus computer environment with direct interface to higher level control processors, uses pulsewidth multiplier power amplifiers, and one unit can control up to sixteen different motors simultaneously at a high I/O rate. UCCS performance capabilities are illustrated by a few data.

  14. Optimal control of a delayed SLBS computer virus model

    NASA Astrophysics Data System (ADS)

    Chen, Lijuan; Hattaf, Khalid; Sun, Jitao

    2015-06-01

    In this paper, a delayed SLBS computer virus model is firstly proposed. To the best of our knowledge, this is the first time to discuss the optimal control of the SLBS model. By using the optimal control strategy, we present an optimal strategy to minimize the total number of the breakingout computers and the cost associated with toxication or detoxication. We show that an optimal control solution exists for the control problem. Some examples are presented to show the efficiency of this optimal control.

  15. Computational architecture for integrated controls and structures design

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith; Park, K. C.

    1989-01-01

    To facilitate the development of control structure interaction (CSI) design methodology, a computational architecture for interdisciplinary design of active structures is presented. The emphasis of the computational procedure is to exploit existing sparse matrix structural analysis techniques, in-core data transfer with control synthesis programs, and versatility in the optimization methodology to avoid unnecessary structural or control calculations. The architecture is designed such that all required structure, control and optimization analyses are performed within one program. Hence, the optimization strategy is not unduly constrained by cold starts of existing structural analysis and control synthesis packages.

  16. Computational methods to obtain time optimal jet engine control

    NASA Technical Reports Server (NTRS)

    Basso, R. J.; Leake, R. J.

    1976-01-01

    Dynamic Programming and the Fletcher-Reeves Conjugate Gradient Method are two existing methods which can be applied to solve a general class of unconstrained fixed time, free right end optimal control problems. New techniques are developed to adapt these methods to solve a time optimal control problem with state variable and control constraints. Specifically, they are applied to compute a time optimal control for a jet engine control problem.

  17. Nasal Anthropometry on Facial Computed Tomography Scans for Rhinoplasty in Koreans

    PubMed Central

    Moon, Kyung Min; Cho, Geon; Sung, Ha Min; Jung, Min Su; Tak, Kyoung Seok; Jung, Sung-Won; Lee, Hoon-Bum

    2013-01-01

    Background Cephalometric analysis is essential for planning treatment in maxillofacial and aesthetic facial surgery. Although photometric analysis of the Korean nose has been attempted in the past, anthropometry of the deeper nasal structures in the same population based on computerized tomography (CT) has not been published. We therefore measured three anthropometric parameters of the nose on CT scans in our clinical series of patients. Methods We conducted the current retrospective study of a total of 100 patients (n=100) who underwent a CT-guided radiological measurement at our institution during a period ranging from January of 2008 to August of 2010. In these patients, we took three anthropometric measurements: the nasofrontal angle, the pyramidal angle, and the linear distance between the nasion and the tip of the nasal bone. Results The mean nasofrontal angle was 131.14° in the male patients and 140.70° in the female patients. The mean linear distance between the nasion and the tip of the nasal bone was 21.28 mm and 18.02 mm, respectively. The mean nasal pyramidal angle was 112.89° and 103.25° at the level of the nasal root, 117.49° and 115.60° at the middle level of the nasal bone, and 127.99° and 125.04° at the level of the tip of the nasal bone, respectively. Conclusions In conclusion, our data will be helpful in the preparation of silicone implants for augmentation and/or corrective rhinoplasty in ethnic Korean people. PMID:24086818

  18. High-Speed Photography with Computer Control.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1991-01-01

    Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

  19. Integrated computer control system architectural overview

    SciTech Connect

    Van Arsdall, P.

    1997-06-18

    This overview introduces the NIF Integrated Control System (ICCS) architecture. The design is abstract to allow the construction of many similar applications from a common framework. This summary lays the essential foundation for understanding the model-based engineering approach used to execute the design.

  20. Quality and accuracy of cone beam computed tomography gated by active breathing control

    SciTech Connect

    Thompson, Bria P.; Hugo, Geoffrey D.

    2008-12-15

    The purpose of this study was to evaluate the quality and accuracy of cone beam computed tomography (CBCT) gated by active breathing control (ABC), which may be useful for image guidance in the presence of respiration. Comparisons were made between conventional ABC-CBCT (stop and go), fast ABC-CBCT (a method to speed up the acquisition by slowing the gantry instead of stopping during free breathing), and free breathing respiration correlated CBCT. Image quality was assessed in phantom. Accuracy of reconstructed voxel intensity, uniformity, and root mean square error were evaluated. Registration accuracy (bony and soft tissue) was quantified with both an anthropomorphic and a quality assurance phantom. Gantry angle accuracy was measured with respect to gantry speed modulation. Conventional ABC-CBCT scan time ranged from 2.3 to 5.8 min. Fast ABC-CBCT scan time ranged from 1.4 to 1.8 min, and respiratory correlated CBCT scans took 2.1 min to complete. Voxel intensity value for ABC gated scans was accurate relative to a normal clinical scan with all projections. Uniformity and root mean square error performance degraded as the number of projections used in the reconstruction of the fast ABC-CBCT scans decreased (shortest breath hold, longest free breathing segment). Registration accuracy for small, large, and rotational corrections was within 1 mm and 1 degree sign . Gantry angle accuracy was within 1 degree sign for all scans. For high-contrast targets, performance for image-guidance purposes was similar for fast and conventional ABC-CBCT scans and respiration correlated CBCT.

  1. Quality and accuracy of cone beam computed tomography gated by active breathing control

    PubMed Central

    Thompson, Bria P.; Hugo, Geoffrey D.

    2008-01-01

    The purpose of this study was to evaluate the quality and accuracy of cone beam computed tomography (CBCT) gated by active breathing control (ABC), which may be useful for image guidance in the presence of respiration. Comparisons were made between conventional ABC-CBCT (stop and go), fast ABC-CBCT (a method to speed up the acquisition by slowing the gantry instead of stopping during free breathing), and free breathing respiration correlated CBCT. Image quality was assessed in phantom. Accuracy of reconstructed voxel intensity, uniformity, and root mean square error were evaluated. Registration accuracy (bony and soft tissue) was quantified with both an anthropomorphic and a quality assurance phantom. Gantry angle accuracy was measured with respect to gantry speed modulation. Conventional ABC-CBCT scan time ranged from 2.3 to 5.8 min. Fast ABC-CBCT scan time ranged from 1.4 to 1.8 min, and respiratory correlated CBCT scans took 2.1 min to complete. Voxel intensity value for ABC gated scans was accurate relative to a normal clinical scan with all projections. Uniformity and root mean square error performance degraded as the number of projections used in the reconstruction of the fast ABC-CBCT scans decreased (shortest breath hold, longest free breathing segment). Registration accuracy for small, large, and rotational corrections was within 1 mm and 1°. Gantry angle accuracy was within 1° for all scans. For high-contrast targets, performance for image-guidance purposes was similar for fast and conventional ABC-CBCT scans and respiration correlated CBCT. PMID:19175117

  2. Computer control of a robotic satellite servicer

    NASA Technical Reports Server (NTRS)

    Fernandez, K. R.

    1980-01-01

    The advantages that will accrue from the in-orbit servicing of satellites are listed. It is noted that in a concept in satellite servicing which holds promise as a compromise between the high flexibility and adaptability of manned vehicles and the lower cost of an unmanned vehicle involves an unmanned servicer carrying a remotely supervised robotic manipulator arm. Because of deficiencies in sensor technology, robot servicing would require that satellites be designed according to a modular concept. A description is given of the servicer simulation hardware, the computer and interface hardware, and the software. It is noted that several areas require further development; these include automated docking, modularization of satellite design, reliable connector and latching mechanisms, development of manipulators for space environments, and development of automated diagnostic techniques.

  3. Rare Root Canal Configuration of Bilateral Maxillary Second Molar Using Cone-beam Computed Tomographic Scanning.

    PubMed

    Zeng, Chang; Shen, Ya; Guan, Xiaoyue; Wang, Xin; Fan, Mingwen; Li, Yuhong

    2016-04-01

    The aim of this article was to present a right maxillary second molar with an unusual root canal morphology of 4 roots and 5 canals as confirmed by cone-beam computed tomographic (CBCT) imaging. The tooth had a C-shaped mesiobuccal root (CBCT imaging revealed that the root was closer to the palate than the buccal side) with 2 canals, 2 fused distobuccal roots with 2 separate canals, and 1 normal bulky palatal root with 1 canal. After thoroughly examining the rare anatomy, root canal treatment was applied on the tooth. This article shows the complexity of maxillary second molar variation and shows the significance of CBCT imaging in the confirmation of the 3-dimensional anatomy of teeth and endodontic treatment. PMID:26920931

  4. Broad Ligament Fibroid Mimicking as Ovarian Tumor on Ultrasonography and Computed Tomography Scan

    PubMed Central

    Rajanna, Dayananda Kumar; Pandey, Vaibhav; Janardhan, Sujit; Datti, Sujatha N

    2013-01-01

    Giant fibroids are known to arise from the uterus, and very rarely from the broad ligament. Large fibroids often undergo hyaline, cystic, and at times, red degeneration. In the present case, cystic degeneration with intervening septations in an adnexal mass raised the suspicion of ovarian neoplasm as the ovaries were not seen as separate from the lesion. The ultrasonographic and contrast-enhanced computed tomographic findings of this case were characteristic of ovarian neoplasm. The differential diagnosis included rare possibility of giant fibroid with cystic degeneration. The diagnosis was confirmed on histopathological examination. The patient underwent excision of the broad ligament fibroid, hysterectomy, and bilateral salpingo-oophorectomy. Magnetic resonance imaging has a role in the diagnosis of such lesions. PMID:23607077

  5. Computational Control of Flexible Aerospace Systems

    NASA Technical Reports Server (NTRS)

    Sharpe, Lonnie, Jr.; Shen, Ji Yao

    1994-01-01

    The main objective of this project is to establish a distributed parameter modeling technique for structural analysis, parameter estimation, vibration suppression and control synthesis of large flexible aerospace structures. This report concentrates on the research outputs produced in the last two years of the project. The main accomplishments can be summarized as follows. A new version of the PDEMOD Code had been completed. A theoretical investigation of the NASA MSFC two-dimensional ground-based manipulator facility by using distributed parameter modelling technique has been conducted. A new mathematical treatment for dynamic analysis and control of large flexible manipulator systems has been conceived, which may provide a embryonic form of a more sophisticated mathematical model for future modified versions of the PDEMOD Codes.

  6. Robust semi-automatic segmentation of pulmonary subsolid nodules in chest computed tomography scans

    NASA Astrophysics Data System (ADS)

    Lassen, B. C.; Jacobs, C.; Kuhnigk, J.-M.; van Ginneken, B.; van Rikxoort, E. M.

    2015-02-01

    The malignancy of lung nodules is most often detected by analyzing changes of the nodule diameter in follow-up scans. A recent study showed that comparing the volume or the mass of a nodule over time is much more significant than comparing the diameter. Since the survival rate is higher when the disease is still in an early stage it is important to detect the growth rate as soon as possible. However manual segmentation of a volume is time-consuming. Whereas there are several well evaluated methods for the segmentation of solid nodules, less work is done on subsolid nodules which actually show a higher malignancy rate than solid nodules. In this work we present a fast, semi-automatic method for segmentation of subsolid nodules. As minimal user interaction the method expects a user-drawn stroke on the largest diameter of the nodule. First, a threshold-based region growing is performed based on intensity analysis of the nodule region and surrounding parenchyma. In the next step the chest wall is removed by a combination of a connected component analyses and convex hull calculation. Finally, attached vessels are detached by morphological operations. The method was evaluated on all nodules of the publicly available LIDC/IDRI database that were manually segmented and rated as non-solid or part-solid by four radiologists (Dataset 1) and three radiologists (Dataset 2). For these 59 nodules the Jaccard index for the agreement of the proposed method with the manual reference segmentations was 0.52/0.50 (Dataset 1/Dataset 2) compared to an inter-observer agreement of the manual segmentations of 0.54/0.58 (Dataset 1/Dataset 2). Furthermore, the inter-observer agreement using the proposed method (i.e. different input strokes) was analyzed and gave a Jaccard index of 0.74/0.74 (Dataset 1/Dataset 2). The presented method provides satisfactory segmentation results with minimal observer effort in minimal time and can reduce the inter-observer variability for segmentation of

  7. Real time computer controlled weld skate

    NASA Technical Reports Server (NTRS)

    Wall, W. A., Jr.

    1977-01-01

    A real time, adaptive control, automatic welding system was developed. This system utilizes the general case geometrical relationships between a weldment and a weld skate to precisely maintain constant weld speed and torch angle along a contoured workplace. The system is compatible with the gas tungsten arc weld process or can be adapted to other weld processes. Heli-arc cutting and machine tool routing operations are possible applications.

  8. Computational control of flexible aerospace systems

    NASA Technical Reports Server (NTRS)

    Sharpe, Lonnie, Jr.; Shen, Ji Yao

    1994-01-01

    The main objective of this project is to establish a distributed parameter modeling technique for structural analysis, parameter estimation, vibration suppression and control synthesis of large flexible aerospace structures. This report concentrates on the research outputs produced in the last two years. The main accomplishments can be summarized as follows. A new version of the PDEMOD Code had been completed based on several incomplete versions. The verification of the code had been conducted by comparing the results with those examples for which the exact theoretical solutions can be obtained. The theoretical background of the package and the verification examples has been reported in a technical paper submitted to the Joint Applied Mechanics & Material Conference, ASME. A brief USER'S MANUAL had been compiled, which includes three parts: (1) Input data preparation; (2) Explanation of the Subroutines; and (3) Specification of control variables. Meanwhile, a theoretical investigation of the NASA MSFC two-dimensional ground-based manipulator facility by using distributed parameter modeling technique has been conducted. A new mathematical treatment for dynamic analysis and control of large flexible manipulator systems has been conceived, which may provide an embryonic form of a more sophisticated mathematical model for future modified versions of the PDEMOD Codes.

  9. Controlling High Power Devices with Computers or TTL Logic Circuits

    ERIC Educational Resources Information Center

    Carlton, Kevin

    2002-01-01

    Computers are routinely used to control experiments in modern science laboratories. This should be reflected in laboratories in an educational setting. There is a mismatch between the power that can be delivered by a computer interfacing card or a TTL logic circuit and that required by many practical pieces of laboratory equipment. One common way…

  10. Computer and control applications in a vegetable processing plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are many advantages to the use of computers and control in food industry. Software in the food industry takes 2 forms - general purpose commercial computer software and software for specialized applications, such as drying and thermal processing of foods. Many applied simulation models for d...

  11. Students' Attitudes towards Control Methods in Computer-Assisted Instruction.

    ERIC Educational Resources Information Center

    Hintze, Hanne; And Others

    1988-01-01

    Describes study designed to investigate dental students' attitudes toward computer-assisted teaching as applied in programs for oral radiology in Denmark. Programs using personal computers and slide projectors with varying degrees of learner and teacher control are described, and differences in attitudes between male and female students are…

  12. Software For Computer-Aided Design Of Control Systems

    NASA Technical Reports Server (NTRS)

    Wette, Matthew

    1994-01-01

    Computer Aided Engineering System (CAESY) software developed to provide means to evaluate methods for dealing with users' needs in computer-aided design of control systems. Interpreter program for performing engineering calculations. Incorporates features of both Ada and MATLAB. Designed to be flexible and powerful. Includes internally defined functions, procedures and provides for definition of functions and procedures by user. Written in C language.

  13. Integrated evolutionary computation neural network quality controller for automated systems

    SciTech Connect

    Patro, S.; Kolarik, W.J.

    1999-06-01

    With increasing competition in the global market, more and more stringent quality standards and specifications are being demands at lower costs. Manufacturing applications of computing power are becoming more common. The application of neural networks to identification and control of dynamic processes has been discussed. The limitations of using neural networks for control purposes has been pointed out and a different technique, evolutionary computation, has been discussed. The results of identifying and controlling an unstable, dynamic process using evolutionary computation methods has been presented. A framework for an integrated system, using both neural networks and evolutionary computation, has been proposed to identify the process and then control the product quality, in a dynamic, multivariable system, in real-time.

  14. 15. Interior view of unoccupied controlled computer room looking at ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Interior view of unoccupied controlled computer room looking at exit door and office; northwest corner of unoccupied portion; view to south. - Ellsworth Air Force Base, Mess & Administration Building, 2279 Risner Drive, Blackhawk, Meade County, SD

  15. LabVIEW control software for scanning micro-beam X-ray fluorescence spectrometer.

    PubMed

    Wrobel, Pawel; Czyzycki, Mateusz; Furman, Leszek; Kolasinski, Krzysztof; Lankosz, Marek; Mrenca, Alina; Samek, Lucyna; Wegrzynek, Dariusz

    2012-05-15

    Confocal micro-beam X-ray fluorescence microscope was constructed. The system was assembled from commercially available components - a low power X-ray tube source, polycapillary X-ray optics and silicon drift detector - controlled by an in-house developed LabVIEW software. A video camera coupled to optical microscope was utilized to display the area excited by X-ray beam. The camera image calibration and scan area definition software were also based entirely on LabVIEW code. Presently, the main area of application of the newly constructed spectrometer is 2-dimensional mapping of element distribution in environmental, biological and geological samples with micrometer spatial resolution. The hardware and the developed software can already handle volumetric 3-D confocal scans. In this work, a front panel graphical user interface as well as communication protocols between hardware components were described. Two applications of the spectrometer, to homogeneity testing of titanium layers and to imaging of various types of grains in air particulate matter collected on membrane filters, were presented. PMID:22483897

  16. An autonomous molecular computer for logical control of gene expression

    NASA Astrophysics Data System (ADS)

    Benenson, Yaakov; Gil, Binyamin; Ben-Dor, Uri; Adar, Rivka; Shapiro, Ehud

    2004-05-01

    Early biomolecular computer research focused on laboratory-scale, human-operated computers for complex computational problems. Recently, simple molecular-scale autonomous programmable computers were demonstrated allowing both input and output information to be in molecular form. Such computers, using biological molecules as input data and biologically active molecules as outputs, could produce a system for `logical' control of biological processes. Here we describe an autonomous biomolecular computer that, at least in vitro, logically analyses the levels of messenger RNA species, and in response produces a molecule capable of affecting levels of gene expression. The computer operates at a concentration of close to a trillion computers per microlitre and consists of three programmable modules: a computation module, that is, a stochastic molecular automaton; an input module, by which specific mRNA levels or point mutations regulate software molecule concentrations, and hence automaton transition probabilities; and an output module, capable of controlled release of a short single-stranded DNA molecule. This approach might be applied in vivo to biochemical sensing, genetic engineering and even medical diagnosis and treatment. As a proof of principle we programmed the computer to identify and analyse mRNA of disease-related genes associated with models of small-cell lung cancer and prostate cancer, and to produce a single-stranded DNA molecule modelled after an anticancer drug.

  17. Present and future utility of computed tomography scanning in the assessment and management of COPD.

    PubMed

    Ostridge, Kristoffer; Wilkinson, Tom M A

    2016-07-01

    Computed tomography (CT) is the modality of choice for imaging the thorax and lung structure. In chronic obstructive pulmonary disease (COPD), it used to recognise the key morphological features of emphysema, bronchial wall thickening and gas trapping. Despite this, its place in the investigation and management of COPD is yet to be determined, and it is not routinely recommended. However, lung CT already has important clinical applications where it can be used to diagnose concomitant pathology and determine which patients with severe emphysema are appropriate for lung volume reduction procedures. Furthermore, novel quantitative analysis techniques permit objective measurements of pulmonary and extrapulmonary manifestations of the disease. These techniques can give important insights into COPD, and help explore the heterogeneity and underlying mechanisms of the condition. In time, it is hoped that these techniques can be used in clinical trials to help develop disease-specific therapy and, ultimately, as a clinical tool in identifying patients who would benefit most from new and existing treatments. This review discusses the current clinical applications for CT imaging in COPD and quantification techniques, and its potential future role in stratifying disease for optimal outcome. PMID:27230448

  18. Spontaneous Acute Mesenteroaxial Gastric Volvulus Diagnosed by Computed Tomography Scan in a Young Man.

    PubMed

    Jabbour, Gaby; Afifi, Ibrahim; Ellabib, Mohamed; El-Menyar, Ayman; Al-Thani, Hassan

    2016-01-01

    BACKGROUND Acute gastric volvulus is a surgical emergency that requires early recognition and treatment. Acute idiopathic mesenteroaxial gastric volvulus is a rare sub-type and there are few cases reported in children and there are even fewer reports in adults. CASE REPORT We report a rare case of a 23-year-old man who presented with a 1-day history of vomiting, epigastric pain, distention, and constipation. The diagnosis for mesenteroaxial type gastric volvulus was confirmed by abdominal radiography and computed tomography. The patient was successfully treated by laparotomy with resection of the ischemic stomach wall and anastomosis. Acute spontaneous mesenteroaxial gastric volvulus is rare in adults and early diagnosis is challenging due to non-specific symptoms. A missed or delayed diagnosis may result in serious complications due to gastric obstruction. CONCLUSIONS A patient presenting with severe epigastric pain and clinical evidence of gastric outlet obstruction should be considered as a surgical emergency to rule out gastric volvulus. High index of suspicion, early diagnosis and prompt surgical management are important for favorable outcome in patients with acute spontaneous gastric volvulus. PMID:27112797

  19. Spontaneous Acute Mesenteroaxial Gastric Volvulus Diagnosed by Computed Tomography Scan in a Young Man

    PubMed Central

    Jabbour, Gaby; Afifi, Ibrahim; Ellabib, Mohamed; El-Menyar, Ayman; Al-Thani, Hassan

    2016-01-01

    Patient: Male, 23 Final Diagnosis: Acute spontaneous gastric volvulus Symptoms: — Medication: — Clinical Procedure: Laparotomy Specialty: Gastroenterology and Hepatology Objective: Rare disease Background: Acute gastric volvulus is a surgical emergency that requires early recognition and treatment. Acute idiopathic mesenteroaxial gastric volvulus is a rare sub-type and there are few cases reported in children and there are even fewer reports in adults. Case Report: We report a rare case of a 23-year-old man who presented with a 1-day history of vomiting, epigastric pain, distention, and constipation. The diagnosis for mesenteroaxial type gastric volvulus was confirmed by abdominal radiography and computed tomography. The patient was successfully treated by laparotomy with resection of the ischemic stomach wall and anastomosis. Acute spontaneous mesenteroaxial gastric volvulus is rare in adults and early diagnosis is challenging due to non-specific symptoms. A missed or delayed diagnosis may result in serious complications due to gastric obstruction. Conclusions: A patient presenting with severe epigastric pain and clinical evidence of gastric outlet obstruction should be considered as a surgical emergency to rule out gastric volvulus. High index of suspicion, early diagnosis and prompt surgical management are important for favorable outcome in patients with acute spontaneous gastric volvulus. PMID:27112797

  20. The Effects of Compensatory Scanning Training on Mobility in Patients with Homonymous Visual Field Defects: A Randomized Controlled Trial

    PubMed Central

    de Haan, Gera A.; Melis-Dankers, Bart J. M.; Brouwer, Wiebo H.; Tucha, Oliver; Heutink, Joost

    2015-01-01

    Introduction Homonymous visual field defects (HVFD) are a common consequence of postchiasmatic acquired brain injury and often lead to mobility-related difficulties. Different types of compensatory scanning training have been developed, aimed at decreasing consequences of the HVFD by changing visual scanning. Aim The aim of the present study is to examine the effects of a compensatory scanning training program using horizontal scanning on mobility-related activities and participation in daily life. Method The main interest of this study is to assess the effectiveness of training on mobility-related activities and participation in daily life. Visual scanning tests, such as dot counting and visual search, and control measures for visual functions and reading have been included as well. First, it is examined how performance on scanning and mobility-related measures is affected in patients with HVFD by comparing scores with scores of a healthy control group (n = 25). Second, the effect of training is assessed using an RCT design, in which performance of 26 patients before and after training is compared to performance of 23 patients in a waiting list control group. Results Self-reported improvements after training were found, accompanied by improvements in detecting peripheral stimuli and avoiding obstacles during walking, especially in dual task situations in which a second task limits the attentional capacity available for compensatory scanning. Training only improved mobility-related activities in which detection of peripheral stimuli is important, while no improvement was found on tests that require other visual skills, such as reading, visual counting and visual search. Conclusion This is the first RCT to evaluate the effects of a compensatory scanning training that is based on a systematic horizontal scanning rhythm. This training improved mobility-related activities. The results suggest that different types of compensatory scanning strategies are appropriate for

  1. Treatment planning for resected abdominal tumors: Differences in organ position between diagnostic and radiation-planning computed tomography scans

    SciTech Connect

    Chen, Aileen B.; Mamon, Harvey . E-mail: hmamon@lroc.harvard.edu

    2005-12-01

    Purpose: To evaluate whether organ location, determined from preoperative diagnostic computed tomography scans (CTs), accurately reflects organ location when patients are positioned for radiation therapy. Methods and Materials: We identified patients with upper abdominal malignancies treated with surgery and/or radiation therapy. Comparisons of organ position relative to fixed bony landmarks were made among preoperative diagnostic CTs, postoperative diagnostic CTs, and radiation-planning CTs. We studied 18 patients who had CTs differing only in scanning technique, 11 patients who had CTs differing only in operative state, and 7 patients with CTs differing in both scanning technique and operative state. Results: For patients with diagnostic CTs and radiation-planning CTs that were either both preoperative or both postoperative, mean organ position, measured relative to a fixed bony landmark, ranged from 1.9 to 3.2 cm superior on radiation-planning CTs compared with diagnostic CTs (p < 0.0001). Mean organ position ranged from 0.9 to 1.7 cm posterior on radiation-planning CTs compared with diagnostic CTs (p {<=} 0.008). Shifts in the right-left direction were small and variable. For patients with pre- and postoperative diagnostic CTs, organ shifts were variable and not significant. Organ shifts for patients with preoperative diagnostic CTs and postoperative radiation-planning CTs were similar to shifts observed for the first group. Conclusions: Relative to bony landmarks, there are superior and posterior shifts in organ position for radiation-planning CTs compared with diagnostic CTs. These shifts should be considered during treatment planning for resected abdominal tumors.

  2. Strategies for efficient scanning and reconstruction methods on very large objects with high-energy x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Reims, Nils; Schoen, Tobias; Boehnel, Michael; Sukowski, Frank; Firsching, Markus

    2014-09-01

    X-ray computed tomography (CT) is an established tool for industrial non-destructive testing purposes. Yet conventional CT devices pose limitations regarding specimen dimensions and material thicknesses. Here we introduce a novel CT system capable of inspecting very large objects (VLO) like automobiles or sea freight containers in 3-D and discuss strategies for efficient scanning and reconstruction methods. The system utilizes a 9 MeV linear accelerator to achieve high penetration lengths in both dense and high-Z materials. The line detector array has an overall length of 4 meters. The presented system allows for reconstruction volumes of 3.2 meters in diameter and 5 meters in height. First we outline the general capabilities of high energy CT imaging and compare it with state of the art 450 kV X-ray systems. The imaging performance is shown based on experimental results. The second part addresses the problem of considerably higher scanning times when using line detectors compared to area detectors. Reducing the number of projections considerably causes image artifacts with standard reconstruction methods like filtered back projection (FBP). Alternative methods which can provide significantly better results are algebraic reconstruction techniques (ART). One of these is compressed sensing (CS) based ART which we discuss regarding its suitability in respect to FBP. We could prove the feasibility of inspecting VLOs like complete automobiles based on experimental data. CS allows for achieving sufficient image quality in terms of spatial and contrast resolution while reducing the number of projections significantly resulting in faster scanning times.

  3. High-stroke silicon-on-insulator MEMS nanopositioner: Control design for non-raster scan atomic force microscopy

    SciTech Connect

    Maroufi, Mohammad Fowler, Anthony G. Bazaei, Ali Moheimani, S. O. Reza

    2015-02-15

    A 2-degree of freedom microelectromechanical systems nanopositioner designed for on-chip atomic force microscopy (AFM) is presented. The device is fabricated using a silicon-on-insulator-based process and is designed as a parallel kinematic mechanism. It contains a central scan table and two sets of electrostatic comb actuators along each orthogonal axis, which provides displacement ranges greater than ±10 μm. The first in-plane resonance modes are located at 1274 Hz and 1286 Hz for the X and Y axes, respectively. To measure lateral displacements of the stage, electrothermal position sensors are incorporated in the design. To facilitate high-speed scans, the highly resonant dynamics of the system are controlled using damping loops in conjunction with internal model controllers that enable accurate tracking of fast sinusoidal set-points. To cancel the effect of sensor drift on controlled displacements, washout controllers are used in the damping loops. The feedback controlled nanopositioner is successfully used to perform several AFM scans in contact mode via a Lissajous scan method with a large scan area of 20 μm × 20 μm. The maximum scan rate demonstrated is 1 kHz.

  4. High-stroke silicon-on-insulator MEMS nanopositioner: control design for non-raster scan atomic force microscopy.

    PubMed

    Maroufi, Mohammad; Fowler, Anthony G; Bazaei, Ali; Moheimani, S O Reza

    2015-02-01

    A 2-degree of freedom microelectromechanical systems nanopositioner designed for on-chip atomic force microscopy (AFM) is presented. The device is fabricated using a silicon-on-insulator-based process and is designed as a parallel kinematic mechanism. It contains a central scan table and two sets of electrostatic comb actuators along each orthogonal axis, which provides displacement ranges greater than ±10 μm. The first in-plane resonance modes are located at 1274 Hz and 1286 Hz for the X and Y axes, respectively. To measure lateral displacements of the stage, electrothermal position sensors are incorporated in the design. To facilitate high-speed scans, the highly resonant dynamics of the system are controlled using damping loops in conjunction with internal model controllers that enable accurate tracking of fast sinusoidal set-points. To cancel the effect of sensor drift on controlled displacements, washout controllers are used in the damping loops. The feedback controlled nanopositioner is successfully used to perform several AFM scans in contact mode via a Lissajous scan method with a large scan area of 20 μm × 20 μm. The maximum scan rate demonstrated is 1 kHz. PMID:25725850

  5. Collateral findings during computed tomography scan for atrial fibrillation ablation: Let’s take a look around

    PubMed Central

    Perna, Francesco; Casella, Michela; Narducci, Maria Lucia; Dello Russo, Antonio; Bencardino, Gianluigi; Pontone, Gianluca; Pelargonio, Gemma; Andreini, Daniele; Vitulano, Nicola; Pizzamiglio, Francesca; Conte, Edoardo; Crea, Filippo; Tondo, Claudio

    2016-01-01

    The growing number of atrial fibrillation catheter ablation procedures warranted the development of advanced cardiac mapping techniques, such as image integration between electroanatomical map and cardiac computed tomography. While scanning the chest before catheter ablation, it is frequent to detect cardiac and extracardiac collateral findings. Most collateral findings are promptly recognized as benign and do not require further attention. However, sometimes clinically relevant collateral findings are detected, which often warrant extra diagnostic examinations or even invasive procedure, and sometimes need to be followed-up over time. Even though reporting and further investigating collateral findings has not shown a clear survival benefit, almost all the working groups providing data on collateral findings reported some collateral findings eventually coming out to be malignancies, sometimes at an early stage. Therefore, there is currently no clear agreement about the right strategy to be followed. PMID:27152143

  6. Estimation of air void and aggregate spatial distributions in concrete under uniaxial compression using computer tomography scanning

    SciTech Connect

    Wong, R.C.K. . E-mail: rckwong@ucalgary.ca; Chau, K.T.

    2005-08-01

    Normal- and high-strength concrete cylinders (designed compressive strengths of 30 and 90 MPa at 28 days) were loaded uniaxially. Computer tomography (CT) scanning technique was used to examine the evolution of air voids inside the specimens at various loading states up to 85% of the ultimate compressive strength. The normal-strength concrete yielded a very different behaviour in changes of internal microstructure as compared to the high-strength concrete. There were significant instances of nucleation and growth in air voids in the normal-strength concrete specimen, while the increase in air voids in the high-strength concrete specimen was insignificant. In addition, CT images were used for mapping the aggregate spatial distributions within the specimens. No intrinsic anisotropy was detected from the fabric analysis.

  7. Improving limited-projection-angle fluorescence molecular tomography using a co-registered x-ray computed tomography scan

    NASA Astrophysics Data System (ADS)

    Radrich, Karin; Ale, Angelique; Ermolayev, Vladimir; Ntziachristos, Vasilis

    2012-12-01

    We examine the improvement in imaging performance, such as axial resolution and signal localization, when employing limited-projection-angle fluorescence molecular tomography (FMT) together with x-ray computed tomography (XCT) measurements versus stand-alone FMT. For this purpose, we employed living mice, bearing a spontaneous lung tumor model, and imaged them with FMT and XCT under identical geometrical conditions using fluorescent probes for cancer targeting. The XCT data was employed, herein, as structural prior information to guide the FMT reconstruction. Gold standard images were provided by fluorescence images of mouse cryoslices, providing the ground truth in fluorescence bio-distribution. Upon comparison of FMT images versus images reconstructed using hybrid FMT and XCT data, we demonstrate marked improvements in image accuracy. This work relates to currently disseminated FMT systems, using limited projection scans, and can be employed to enhance their performance.

  8. Computed-tomography scan-based finite element analysis of stress distribution in premolars restored with composite resin

    NASA Astrophysics Data System (ADS)

    Kantardžić, I.; Vasiljević, D.; Blažić, L.; Puškar, T.; Tasić, M.

    2012-05-01

    Mechanical properties of restorative material have an effect on stress distribution in the tooth structure and the restorative material during mastication. The aim of this study was to investigate the influence of restorative materials with different moduli of elasticity on stress distribution in the three-dimensional (3D) solid tooth model. Computed tomography scan data of human maxillary second premolars were used for 3D solid model generation. Four composite resins with a modulus of elasticity of 6700, 9500, 14 100 and 21 000 MPa were considered to simulate four different clinical direct restoration types. Each model was subjected to a resulting force of 200 N directed to the occlusal surface, and stress distribution and maximal von Mises stresses were calculated using finite-element analysis. We found that the von Mises stress values and stress distribution in tooth structures did not vary considerably with changing the modulus of elasticity of restorative material.

  9. Variability in Distal Femoral Anatomy in Patients Undergoing Total Knee Arthroplasty: Measurements on 13,546 Computed Tomography Scans.

    PubMed

    Meric, Gokhan; Gracitelli, Guilherme C; Aram, Luke J; Swank, Michael L; Bugbee, William D

    2015-10-01

    Proper mechanical and rotational alignment plays an important role in achieving the success of the total knee arthroplasty (TKA). The purpose of the present study was to retrospectively determine with computed tomography (CT) the distal femoral valgus angle (DFVA) and femoral rotation angle (FRA). Our cohort included 13,546 CT scans of patients undergoing TKA. The average DFVA was 5.7 ± 2.3° (range from 1 to -16°) with 13.8% of patients identified as outliers. The distal FRA angle average was 3.3 ± 1.5° (range from -3 to 11°) with 2.8% of patients identified as outliers. These data can be useful in making orthopedic surgeons aware of the variability of femoral anatomy. Using the same cutting angle may lead to malposition of the femoral component. PMID:26021904

  10. Study of carpal bone morphology and position in three dimensions by image analysis from computed tomography scans of the wrist.

    PubMed

    Canovas, F; Roussanne, Y; Captier, G; Bonnel, F

    2004-06-01

    The morphology and positioning of the carpal bones were studied in three dimensions in 18 normal adults on computed tomography (CT) scans of the wrist. The digital data from each CT scan were processed to extract the carpal bones and to automatically characterize their geometry (geometric centroid, principal axes of inertia) using specific software tools. Biometric and angular parameters were defined for this purpose, and most of these parameters showed a normal distribution. The mean distance between the geometric centroid of the capitate and that of the triquetrum, expressed as a relationship to the length of the first principal axis of inertia of the capitate, was found to be the greatest (157.6%+/-8.4%), whereas the smallest mean distance was between the hamate and triquetrum (91.4%+/-7.3%). In the sagittal plane, the first principal axis of inertia of the bones of the first carpal row projected in front of the vertical axis of the orthogonal reference system, whereas the first principal axis of the capitate projected behind it. Measurements using this methodology are far more numerous than those from standard plain radiographs and have the additional advantage of being independent of the examiner. Future investigations on normal wrists should provide a normal range for each quantitative parameter, and comparative study of normal and pathologic wrist measurements should help to define the most relevant parameters for specific traumatic pathologies of the wrist. PMID:15173959

  11. Diagnostic Yield of Computed Tomography Scan for Pediatric Hearing Loss: A Systematic Review

    PubMed Central

    Chen, Jenny X.; Kachniarz, Bart; Shin, Jennifer J.

    2015-01-01

    Background Computed tomography (CT) has been used in the assessment of pediatric hearing loss, but concern regarding radiation risk and increased utilization of magnetic resonance imaging (MRI) have prompted us toward a more quantitative and sophisticated understanding of CT’s potential diagnostic yield. Objective To perform a systematic review to analyze the diagnostic yield of CT for pediatric hearing loss, including subgroup evaluation according to impairment severity and laterality, as well as the specific findings of enlarged vestibular aqueduct and narrow cochlear nerve canal. Data Sources PubMed, EMBASE, and the Cochrane Library were assessed from the date of their inception to December 2013. In addition, manual searches of bibliographies were performed and topic experts were contacted. Review Methods Data from studies describing the use of CT in the diagnostic evaluation of pediatric patients with hearing loss of unknown etiology were evaluated, according to a priori inclusion/exclusion criteria. Two independent evaluators corroborated the extracted data. Heterogeneity was evaluated according to the I2 statistic. Results In 50 criteria-meeting studies, the overall diagnostic yield of CT ranged from 7% to 74%, with the strongest and aggregate data demonstrating a point estimate of 30%. This estimate corresponded to a number needed to image of 4 (range, 2–15). The most commonly identified findings were enlarged vestibular aqueduct and cochlear anomalies. The largest studies showed a 4% to 7% yield for narrow cochlear nerve canal. Conclusion These data, along with similar analyses of radiation risk and risks/benefits of sedated MRI, may be used to help guide the choice of diagnostic imaging. PMID:25186339

  12. Ultrasound-guided versus computed tomography-scan guided biopsy of pleural-based lung lesions

    PubMed Central

    Khosla, Rahul; McLean, Anna W; Smith, Jessica A

    2016-01-01

    Background: Computed tomography (CT) guided biopsies have long been the standard technique to obtain tissue from the thoracic cavity and is traditionally performed by interventional radiologists. Ultrasound (US) guided biopsy of pleural-based lesions, performed by pulmonologists is gaining popularity and has the advantage of multi-planar imaging, real-time technique, and the absence of radiation exposure to patients. In this study, we aim to determine the diagnostic accuracy, the time to diagnosis after the initial consult placement, and the complications rates between the two different modalities. Methods: A retrospective study of electronic medical records was done of patients who underwent CT-guided biopsies and US-guided biopsies for pleural-based lesions between 2005 and 2014 and the data collected were analyzed for comparing the two groups. Results: A total of 158 patients underwent 162 procedures during the study period. 86 patients underwent 89 procedures in the US group, and 72 patients underwent 73 procedures in the CT group. The overall yield in the US group was 82/89 (92.1%) versus 67/73 (91.8%) in the CT group (P = 1.0). Average days to the procedure was 7.2 versus 17.5 (P = 0.00001) in the US and CT group, respectively. Complication rate was higher in CT group 17/73 (23.3%) versus 1/89 (1.1%) in the US group (P < 0.0001). Conclusions: For pleural-based lesions the diagnostic accuracy of US guided biopsy is similar to that of CT-guided biopsy, with a lower complication rate and a significantly reduced time to the procedure. PMID:27625440

  13. Oxidation of GaSb(100) and its control studied by scanning tunneling microscopy and spectroscopy

    SciTech Connect

    Mäkelä, J. E-mail: pekka.laukkanen@utu.fi Tuominen, M.; Yasir, M.; Dahl, J.; Punkkinen, M. P. J.; Laukkanen, P. E-mail: pekka.laukkanen@utu.fi Kokko, K.; Kuzmin, M.; Wallace, R. M. E-mail: pekka.laukkanen@utu.fi

    2015-08-10

    Atomic-scale knowledge and control of oxidation of GaSb(100), which is a potential interface for energy-efficient transistors, are still incomplete, largely due to an amorphous structure of GaSb(100) oxides. We elucidate these issues with scanning-tunneling microscopy and spectroscopy. The unveiled oxidation-induced building blocks cause defect states above Fermi level around the conduction-band edge. By interconnecting the results to previous photoemission findings, we suggest that the oxidation starts with substituting second-layer Sb sites by oxygen. Adding small amount of indium on GaSb(100), resulting in a (4 × 2)-In reconstruction, before oxidation produces a previously unreported, crystalline oxidized layer of (1 × 3)-O free of gap states.

  14. Oxidation of GaSb(100) and its control studied by scanning tunneling microscopy and spectroscopy

    NASA Astrophysics Data System (ADS)

    Mäkelä, J.; Tuominen, M.; Yasir, M.; Kuzmin, M.; Dahl, J.; Punkkinen, M. P. J.; Laukkanen, P.; Kokko, K.; Wallace, R. M.

    2015-08-01

    Atomic-scale knowledge and control of oxidation of GaSb(100), which is a potential interface for energy-efficient transistors, are still incomplete, largely due to an amorphous structure of GaSb(100) oxides. We elucidate these issues with scanning-tunneling microscopy and spectroscopy. The unveiled oxidation-induced building blocks cause defect states above Fermi level around the conduction-band edge. By interconnecting the results to previous photoemission findings, we suggest that the oxidation starts with substituting second-layer Sb sites by oxygen. Adding small amount of indium on GaSb(100), resulting in a (4 × 2)-In reconstruction, before oxidation produces a previously unreported, crystalline oxidized layer of (1 × 3)-O free of gap states.

  15. Ku-Band Traveling Wave Slot Array Using Simple Scanning Control

    NASA Technical Reports Server (NTRS)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix A.

    2015-01-01

    This poster introduces a feeding concept aimed at simplifying the backend (phase shifters) of traditional phased arrays. As an alternative to traditional phased arrays, we employ a traveling wave array (TWA) using a single feedline whose propagation constant is controlled via a single, small mechanical movement without a need for phase shifters to enable scanning. Specifically, a dielectric plunger is positioned within a parallel plate waveguide (PPW) transmission line (TL) that feeds the TWA. By adjusting the position of the dielectric plunger within the PPW feeding the TWA, beam steering is achieved. A 20-element array is designed at 13 gigaherz shown to give stable realized gain across the angular range of minus 25 degrees less than or equal to theta and less than or equal to 25 degrees. A proof of concept array is fabricated and measured to demonstrate and validate the concept's operation.

  16. Ku-Band Traveling Wave Slot Array Using Simple Scanning Control

    NASA Technical Reports Server (NTRS)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix A.

    2015-01-01

    This paper introduces a feeding concept aimed at simplifying the backend (phase shifters) of traditional phased arrays. As an alternative to traditional phased arrays, we employ a traveling wave array (TWA) using a single feedline whose propagation constant is controlled via a single, small mechanical movement without a need for phase shifters to enable scanning. Specifically, a dielectric plunger is positioned within a parallel plate waveguide (PPW) transmission line (TL) that feeds the TWA. By adjusting the position of the dielectric plunger within the PPW feeding the TWA, beam steering is achieved. A 20 element array is designed at 13GHz shown to give stable realized gain across the angular range of -25 deg. less than or equal to theta less than or equal to 25 deg. A proof of concept array is fabricated and measured to demonstrate and validate the concept's operation.

  17. An Annotated and Cross-Referenced Bibliography on Computer Security and Access Control in Computer Systems.

    ERIC Educational Resources Information Center

    Bergart, Jeffrey G.; And Others

    This paper represents a careful study of published works on computer security and access control in computer systems. The study includes a selective annotated bibliography of some eighty-five important published results in the field and, based on these papers, analyzes the state of the art. In annotating these works, the authors try to be…

  18. Shared resource control between human and computer

    NASA Technical Reports Server (NTRS)

    Hendler, James; Wilson, Reid

    1989-01-01

    The advantages of an AI system of actively monitoring human control of a shared resource (such as a telerobotic manipulator) are presented. A system is described in which a simple AI planning program gains efficiency by monitoring human actions and recognizing when the actions cause a change in the system's assumed state of the world. This enables the planner to recognize when an interaction occurs between human actions and system goals, and allows maintenance of an up-to-date knowledge of the state of the world and thus informs the operator when human action would undo a goal achieved by the system, when an action would render a system goal unachievable, and efficiently replans the establishment of goals after human intervention.

  19. Computational Analysis of Dual Radius Circulation Control Airfoils

    NASA Technical Reports Server (NTRS)

    Lee-Rausch, E. M.; Vatsa, V. N.; Rumsey, C. L.

    2006-01-01

    The goal of the work is to use multiple codes and multiple configurations to provide an assessment of the capability of RANS solvers to predict circulation control dual radius airfoil performance and also to identify key issues associated with the computational predictions of these configurations that can result in discrepancies in the predicted solutions. Solutions were obtained for the Georgia Tech Research Institute (GTRI) dual radius circulation control airfoil and the General Aviation Circulation Control (GACC) dual radius airfoil. For the GTRI-DR airfoil, two-dimensional structured and unstructured grid computations predicted the experimental trend in sectional lift variation with blowing coefficient very well. Good code to code comparisons between the chordwise surface pressure coefficients and the solution streamtraces also indicated that the detailed flow characteristics were matched between the computations. For the GACC-DR airfoil, two-dimensional structured and unstructured grid computations predicted the sectional lift and chordwise pressure distributions accurately at the no blowing condition. However at a moderate blowing coefficient, although the code to code variation was small, the differences between the computations and experiment were significant. Computations were made to investigate the sensitivity of the sectional lift and pressure distributions to some of the experimental and computational parameters, but none of these could entirely account for the differences in the experimental and computational results. Thus, CFD may indeed be adequate as a prediction tool for dual radius CC flows, but limited and difficult to obtain two-dimensional experimental data prevents a confident assessment at this time.

  20. Safety Metrics for Human-Computer Controlled Systems

    NASA Technical Reports Server (NTRS)

    Leveson, Nancy G; Hatanaka, Iwao

    2000-01-01

    The rapid growth of computer technology and innovation has played a significant role in the rise of computer automation of human tasks in modem production systems across all industries. Although the rationale for automation has been to eliminate "human error" or to relieve humans from manual repetitive tasks, various computer-related hazards and accidents have emerged as a direct result of increased system complexity attributed to computer automation. The risk assessment techniques utilized for electromechanical systems are not suitable for today's software-intensive systems or complex human-computer controlled systems.This thesis will propose a new systemic model-based framework for analyzing risk in safety-critical systems where both computers and humans are controlling safety-critical functions. A new systems accident model will be developed based upon modem systems theory and human cognitive processes to better characterize system accidents, the role of human operators, and the influence of software in its direct control of significant system functions Better risk assessments will then be achievable through the application of this new framework to complex human-computer controlled systems.

  1. Pattern of computed tomography scan findings in children with Wilms’ tumor in a tertiary hospital in Lagos, Nigeria

    PubMed Central

    Olukayode, A. Adegboyega; Richard, I. Osuoji; Rachael, A. Akinola; Babajide, O. Balogun; Ireti, O. Faturoti; Gbolahan, O. Awosanya

    2014-01-01

    Context: Abnormal abdominal distension in a child is usually a source of great concern and apprehension in both the parents and the pediatric surgeon. Although Wilms’ tumor is the most common malignant abdominal childhood tumor, usually causing abdominal distension, many other less common causes can also result in abdominal distension. Therefore, early diagnosis of Wilms’ tumor and distinguishing it from all these other causes is essential. Aims: We intend to document the pattern of computed tomography (CT) scan findings in patients with Wilms’ tumor and the peculiarity of its radiological presentation in this environment, highlighting its accuracy and advantages over other imaging modalities. Settings and Design: This is a prospective descriptive study conducted between January, 2011 to January 2012, where all infants, 6-96 months of age, who were suspected to have Wilms’ tumor were made to undergo CT scan examination as part of their management work-up. It was carried out in a teaching hospital. Subjects and Methods: The study performed on 12 children age range of 6-96 months old underwent abdominal CT scans as part of their clinical work-up using a GE Hi-speed dual CT scanner®. Pre- and post-contrast images were acquired and assessed by the radiologists. They were operated and their radiological and histopathology results were correlated. Statistical Analysis: All data was entered into a Microsoft word excel spread sheet and analyzed by simple analysis. Percentages and proportions were determined for categorical variables. Results: Of the 12 patients seen, nearly 75% were males, with a male to female ratio of 3:1 and an average age of 37 months. The right sided tumors were slightly more than the left and nearly 25% were bilateral. Approximately 17% showed punctuate calcifications. Heterogeneous contrast enhancement was seen in all the cases, vascular encasement in three and lymphadenopathy in six cases. There was no bony involvement in any of them but

  2. Control in the cockpit: crews vs. computers.

    PubMed

    Ropelewski, R

    1996-08-01

    In the no-holds-barred competition between Boeing and Europe's Airbus Industrie for dominance in the world's commercial jet airliner markets, the question of who--or what--is in charge in the cockpit has been a significant selling point. Airbus, which pioneered highly automated flight controls with its A320 narrow-body transport in the late 1980s, likes to emphasize the "protection" features built into the aircraft through those automated systems. Boeing, which employs many of the same concepts in its new 777 twin-engine widebody transport, tends to put more emphasis on crew involvement in the operation of that aircraft. Is there a difference? In fact, the question has broader implications than those involving the marketing battle between Boeing and Airbus. Airlines, aircraft manufacturers, flight training specialists, human factors gurus, and aviation authorities in various countries are struggling with the isse as automation becomes more and more prevalent on passenger and cargo-carrying aircraft around the world. PMID:11538995

  3. Computer simulation of vasectomy for wolf control

    USGS Publications Warehouse

    Haight, R.G.; Mech, L.D.

    1997-01-01

    Recovering gray wolf (Canis lupus) populations in the Lake Superior region of the United States are prompting state management agencies to consider strategies to control population growth. In addition to wolf removal, vasectomy has been proposed. To predict the population effects of different sterilization and removal strategies, we developed a simulation model of wolf dynamics using simple rules for demography and dispersal. Simulations suggested that the effects of vasectomy and removal in a disjunct population depend largely on the degree of annual immigration. With low immigration, periodic sterilization reduced pup production and resulted in lower rates of territory recolonization. Consequently, average pack size, number of packs, and population size were significantly less than those for an untreated population. Periodically removing a proportion of the population produced roughly the same trends as did sterilization; however, more than twice as many wolves had to be removed than sterilized. With high immigration, periodic sterilization reduced pup production but not territory recolonization and produced only moderate reductions in population size relative to an untreated population. Similar reductions in population size were obtained by periodically removing large numbers of wolves. Our analysis does not address the possible effects of vasectomy on larger wolf populations, but it suggests that the subject should be considered through modeling or field testing.

  4. SU-E-T-314: The Application of Cloud Computing in Pencil Beam Scanning Proton Therapy Monte Carlo Simulation

    SciTech Connect

    Wang, Z; Gao, M

    2014-06-01

    Purpose: Monte Carlo simulation plays an important role for proton Pencil Beam Scanning (PBS) technique. However, MC simulation demands high computing power and is limited to few large proton centers that can afford a computer cluster. We study the feasibility of utilizing cloud computing in the MC simulation of PBS beams. Methods: A GATE/GEANT4 based MC simulation software was installed on a commercial cloud computing virtual machine (Linux 64-bits, Amazon EC2). Single spot Integral Depth Dose (IDD) curves and in-air transverse profiles were used to tune the source parameters to simulate an IBA machine. With the use of StarCluster software developed at MIT, a Linux cluster with 2–100 nodes can be conveniently launched in the cloud. A proton PBS plan was then exported to the cloud where the MC simulation was run. Results: The simulated PBS plan has a field size of 10×10cm{sup 2}, 20cm range, 10cm modulation, and contains over 10,000 beam spots. EC2 instance type m1.medium was selected considering the CPU/memory requirement and 40 instances were used to form a Linux cluster. To minimize cost, master node was created with on-demand instance and worker nodes were created with spot-instance. The hourly cost for the 40-node cluster was $0.63 and the projected cost for a 100-node cluster was $1.41. Ten million events were simulated to plot PDD and profile, with each job containing 500k events. The simulation completed within 1 hour and an overall statistical uncertainty of < 2% was achieved. Good agreement between MC simulation and measurement was observed. Conclusion: Cloud computing is a cost-effective and easy to maintain platform to run proton PBS MC simulation. When proton MC packages such as GATE and TOPAS are combined with cloud computing, it will greatly facilitate the pursuing of PBS MC studies, especially for newly established proton centers or individual researchers.

  5. A computer simulation approach to measurement of human control strategy

    NASA Technical Reports Server (NTRS)

    Green, J.; Davenport, E. L.; Engler, H. F.; Sears, W. E., III

    1982-01-01

    Human control strategy is measured through use of a psychologically-based computer simulation which reflects a broader theory of control behavior. The simulation is called the human operator performance emulator, or HOPE. HOPE was designed to emulate control learning in a one-dimensional preview tracking task and to measure control strategy in that setting. When given a numerical representation of a track and information about current position in relation to that track, HOPE generates positions for a stick controlling the cursor to be moved along the track. In other words, HOPE generates control stick behavior corresponding to that which might be used by a person learning preview tracking.

  6. Computer-Assisted Instruction in AIDS Infection Control for Physicians.

    ERIC Educational Resources Information Center

    Garrett, T. J.; And Others

    1990-01-01

    A microcomputer program to provide health care workers with instruction in Acquired Immune Deficiency Syndrome (AIDS) infection control was assessed by medical residents. The experimental group (n=24) acquired more knowledge than controls (n=33). Response to the method was positive, and computer-assisted instruction is seen as useful for AIDS…

  7. Control Law Design in a Computational Aeroelasticity Environment

    NASA Technical Reports Server (NTRS)

    Newsom, Jerry R.; Robertshaw, Harry H.; Kapania, Rakesh K.

    2003-01-01

    A methodology for designing active control laws in a computational aeroelasticity environment is given. The methodology involves employing a systems identification technique to develop an explicit state-space model for control law design from the output of a computational aeroelasticity code. The particular computational aeroelasticity code employed in this paper solves the transonic small disturbance aerodynamic equation using a time-accurate, finite-difference scheme. Linear structural dynamics equations are integrated simultaneously with the computational fluid dynamics equations to determine the time responses of the structure. These structural responses are employed as the input to a modern systems identification technique that determines the Markov parameters of an "equivalent linear system". The Eigensystem Realization Algorithm is then employed to develop an explicit state-space model of the equivalent linear system. The Linear Quadratic Guassian control law design technique is employed to design a control law. The computational aeroelasticity code is modified to accept control laws and perform closed-loop simulations. Flutter control of a rectangular wing model is chosen to demonstrate the methodology. Various cases are used to illustrate the usefulness of the methodology as the nonlinearity of the aeroelastic system is increased through increased angle-of-attack changes.

  8. Generating dynamic simulations of movement using computed muscle control.

    PubMed

    Thelen, Darryl G; Anderson, Frank C; Delp, Scott L

    2003-03-01

    Computation of muscle excitation patterns that produce coordinated movements of muscle-actuated dynamic models is an important and challenging problem. Using dynamic optimization to compute excitation patterns comes at a large computational cost, which has limited the use of muscle-actuated simulations. This paper introduces a new algorithm, which we call computed muscle control, that uses static optimization along with feedforward and feedback controls to drive the kinematic trajectory of a musculoskeletal model toward a set of desired kinematics. We illustrate the algorithm by computing a set of muscle excitations that drive a 30-muscle, 3-degree-of-freedom model of pedaling to track measured pedaling kinematics and forces. Only 10 min of computer time were required to compute muscle excitations that reproduced the measured pedaling dynamics, which is over two orders of magnitude faster than conventional dynamic optimization techniques. Simulated kinematics were within 1 degrees of experimental values, simulated pedal forces were within one standard deviation of measured pedal forces for nearly all of the crank cycle, and computed muscle excitations were similar in timing to measured electromyographic patterns. The speed and accuracy of this new algorithm improves the feasibility of using detailed musculoskeletal models to simulate and analyze movement. PMID:12594980

  9. Control and characterization of cyclopentene unimolecular dissociation on Si(100) with scanning tunneling microscopy.

    PubMed

    Yoder, Nathan L; Fakonas, James S; Hersam, Mark C

    2009-07-29

    Dissociation of individual cyclopentene molecules on the Si(100) surface is induced and investigated using cryogenic ultrahigh vacuum scanning tunneling microscopy (STM). Using a secondary feedback loop during elevated tunneling current and sample biasing conditions, the cyclopentene dissociation products are isolated and then characterized with atomic-scale spatial resolution. Using multibias STM and density functional theory, the cyclopentene dissociation products are shown to consist of a C(5)H(7) fragment and an individual H atom. The C(5)H(7) fragment contains a C=C double bond and is bound to the Si(100) surface via a single Si-C covalent bond, while the individual H atom can be induced to hop between two sites on a single silicon dimer with the STM tip. This study shows that the use of feedback control during STM-induced single molecule reactions allows transient reaction products to be captured and thus more thoroughly studied. While demonstrated here for cyclopentene on Si(100), this feedback-controlled approach can likely be applied to a wide array of chemical reactions on semiconductor surfaces. PMID:19572713

  10. Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules.

    PubMed

    Leinen, Philipp; Green, Matthew F B; Esat, Taner; Wagner, Christian; Tautz, F Stefan; Temirov, Ruslan

    2015-01-01

    Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM) is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM) introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926-1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf) of the non-contact atomic force microscope (NC-AFM) tuning fork sensor as well as the magnitude of the electric current (I) flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111) surface. PMID:26665087

  11. Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules

    PubMed Central

    Leinen, Philipp; Green, Matthew F B; Esat, Taner; Wagner, Christian; Tautz, F Stefan

    2015-01-01

    Summary Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM) is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM) introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926–1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf) of the non-contact atomic force microscope (NC-AFM) tuning fork sensor as well as the magnitude of the electric current (I) flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111) surface. PMID:26665087

  12. Design and Implementation of a Mechanical Control System for the Scanning Microwave Limb Sounder

    NASA Technical Reports Server (NTRS)

    Bowden, William

    2011-01-01

    The Scanning Microwave Limb Sounder (SMLS) will use technological improvements in low noise mixers to provide precise data on the Earth's atmospheric composition with high spatial resolution. This project focuses on the design and implementation of a real time control system needed for airborne engineering tests of the SMLS. The system must coordinate the actuation of optical components using four motors with encoder readback, while collecting synchronized telemetric data from a GPS receiver and 3-axis gyrometric system. A graphical user interface for testing the control system was also designed using Python. Although the system could have been implemented with a FPGA-based setup, we chose to use a low cost processor development kit manufactured by XMOS. The XMOS architecture allows parallel execution of multiple tasks on separate threads-making it ideal for this application and is easily programmed using XC (a subset of C). The necessary communication interfaces were implemented in software, including Ethernet, with significant cost and time reduction compared to an FPGA-based approach. For these reasons, the XMOS technology is an attractive, cost effective, alternative to FPGA-based technologies for this design and similar rapid prototyping projects.

  13. Arranging computer architectures to create higher-performance controllers

    NASA Technical Reports Server (NTRS)

    Jacklin, Stephen A.

    1988-01-01

    Techniques for integrating microprocessors, array processors, and other intelligent devices in control systems are reviewed, with an emphasis on the (re)arrangement of components to form distributed or parallel processing systems. Consideration is given to the selection of the host microprocessor, increasing the power and/or memory capacity of the host, multitasking software for the host, array processors to reduce computation time, the allocation of real-time and non-real-time events to different computer subsystems, intelligent devices to share the computational burden for real-time events, and intelligent interfaces to increase communication speeds. The case of a helicopter vibration-suppression and stabilization controller is analyzed as an example, and significant improvements in computation and throughput rates are demonstrated.

  14. Effect of various environments and computed tomography scanning parameters on renal volume measurements in vitro: A phantom study

    PubMed Central

    Liu, Wangyan; Zhu, Yinsu; Tang, Lijun; Zhu, Xiaomei; Xu, Yi; Yang, Guanyu

    2016-01-01

    Kidney volume is an important parameter in clinical practice, and accurate assessment of kidney volume is vital. The aim of the present study was to evaluate the effect of various environments, tube voltages, tube currents and slice thicknesses on the accuracy of a novel segmentation software in determining renal volume on computed tomography (CT) images. The volumes of potatoes and porcine kidneys were measured on CT images and compared with the actual volumes, which were determined by a water displacement method. CT scans were performed under various situations, including different environments (air or oil); tube voltages/tube currents (80 kVp/200 mAs, 120 kVp/200 mAs, 120 kVp/100 mAs); and reconstructed slice thicknesses (0.75 or 1.5 mm). Percentage errors (PEs) relative to the reference standards were calculated. In addition, attenuation and image noise under different CT scanning parameters were compared. Student's t-test was also used to analyze the effect of various conditions on image quality and volume measurements. The results indicated that the volumes measured in oil were closer to the actual volumes (P<0.05). Furthermore, attenuation and image noise significantly increased when using a tube voltage of 80 kVp, while the mean PEs between 120 and 80 kVp voltages were not significantly different. The mean PEs were greater when using a tube current of 100 mAs compared with a current of 200 mAs (P<0.05). In addition, the volumes measured on 1.5 mm slice thickness were closer to the actual volumes (P<0.05). In conclusion, different environments, tube currents and slice thicknesses may affect the volume measurements. In the present study, the most accurate volume measurements were obtained at 120 kVp/200 mAs and a slice thickness of 1.5 mm. PMID:27446271

  15. Comparisons of Derived Metrics from Computed Tomography (CT) Scanned Images of Fluvial Sediment from Gravel-Bed Flume Experiments

    NASA Astrophysics Data System (ADS)

    Voepel, Hal; Ahmed, Sharif; Hodge, Rebecca; Leyland, Julian; Sear, David

    2016-04-01

    Uncertainty in bedload estimates for gravel bed rivers is largely driven by our inability to characterize arrangement, orientation and resultant forces of fluvial sediment in river beds. Water working of grains leads to structural differences between areas of the bed through particle sorting, packing, imbrication, mortaring and degree of bed armoring. In this study, non-destructive, micro-focus X-ray computed tomography (CT) imaging in 3D is used to visualize, quantify and assess the internal geometry of sections of a flume bed that have been extracted keeping their fabric intact. Flume experiments were conducted at 1:1 scaling of our prototype river. From the volume, center of mass, points of contact, and protrusion of individual grains derived from 3D scan data we estimate 3D static force properties at the grain-scale such as pivoting angles, buoyancy and gravity forces, and local grain exposure. Here metrics are derived for images from two flume experiments: one with a bed of coarse grains (>4mm) and the other where sand and clay were incorporated into the coarse flume bed. In addition to deriving force networks, comparison of metrics such as critical shear stress, pivot angles, grain distributions, principle axis orientation, and pore space over depth are made. This is the first time bed stability has been studied in 3D using CT scanned images of sediment from the bed surface to depths well into the subsurface. The derived metrics, inter-granular relationships and characterization of bed structures will lead to improved bedload estimates with reduced uncertainty, as well as improved understanding of relationships between sediment structure, grain size distribution and channel topography.

  16. Cone-Beam Computed Tomography: Imaging Dose during CBCT Scan Acquisition and Accuracy of CBCT Based Dose Calculations

    NASA Astrophysics Data System (ADS)

    Giles, David Matthew

    Cone beam computed tomography (CBCT) is a recent development in radiotherapy for use in image guidance. Image guided radiotherapy using CBCT allows visualization of soft tissue targets and critical structures prior to treatment. Dose escalation is made possible by accurately localizing the target volume while reducing normal tissue toxicity. The kilovoltage x-rays of the cone beam imaging system contribute additional dose to the patient. In this study a 2D reference radiochromic film dosimetry method employing GAFCHROMIC(TM) model XR-QA film is used to measure point skin doses and dose profiles from the Elekta XVI CBCT system integrated onto the Synergy linac. The soft tissue contrast of the daily CBCT images makes adaptive radiotherapy possible in the clinic. In order to track dose to the patient or utilize on-line replanning for adaptive radiotherapy the CBCT images must be used to calculate dose. A Hounsfield unit calibration method for scatter correction is investigated for heterogeneity corrected dose calculation in CBCT images. Three Hounsfield unit to density calibration tables are used for each of four cases including patients and an anthropomorphic phantom, and the calculated dose from each is compared to results from the clinical standard fan beam CT. The dose from the scan acquisition is reported and the effect of scan geometry and total output of the x-ray tube on dose magnitude and distribution is shown. The ability to calculate dose with CBCT is shown to improve with the use of patient specific density tables for scatter correction, and for high beam energies the calculated dose agreement is within 1%.

  17. Determination of Internal Target Volume From a Single Positron Emission Tomography/Computed Tomography Scan in Lung Cancer

    SciTech Connect

    Chang Guoping; Chang Tingting; Pan Tinsu; Clark, John W.; Mawlawi, Osama R.

    2012-05-01

    Purpose: The use of four-dimensional computed tomography (4D-CT) to determine the tumor internal target volume (ITV) is usually characterized by high patient radiation exposure. The objective of this study was to propose and evaluate an approach that relies on a single static positron emission tomography (PET)/CT scan to determine the ITV, thereby eliminating the need for 4D-CT and thus reduce patient radiation dose. Methods and Materials: The proposed approach is based on the concept that the observed PET image is the result of a joint convolution of an ideal PET image (free from motion and partial volume effect) with a motion-blurring kernel (MBK) and partial volume effect. In this regard, the MBK and tumor ITV are then estimated from the deconvolution of this joint model. To test this technique, phantom and patient studies were performed using different sphere/tumor sizes and motion trajectories. In all studies, a 4D-CT and a PET/CT image of the sphere/tumor were acquired. The ITV from the proposed technique was then compared to the maximum intensity projection (MIP) volume of the 4D-CT images. A Dice coefficient of the two volumes was calculated to represent the similarity between the two ITVs. Results: The average ITVs of the proposed technique were 97.2% {+-} 0.3% and 81.0% {+-} 16.7% similar to the MIP volume in the phantom and patient studies, respectively. The average dice coefficients were 0.87 {+-} 0.05 and 0.73 {+-} 0.16, respectively, for the two studies. Conclusion: Using the proposed approach, a single static PET/CT scan has the potential to replace a 4D-CT to determine the tumor ITV. This approach has the added advantage of reducing patient radiation exposure and determining the tumor MBK compared to 4D-CT/MIP-CT.

  18. HelioScan: a software framework for controlling in vivo microscopy setups with high hardware flexibility, functional diversity and extendibility.

    PubMed

    Langer, Dominik; van 't Hoff, Marcel; Keller, Andreas J; Nagaraja, Chetan; Pfäffli, Oliver A; Göldi, Maurice; Kasper, Hansjörg; Helmchen, Fritjof

    2013-04-30

    Intravital microscopy such as in vivo imaging of brain dynamics is often performed with custom-built microscope setups controlled by custom-written software to meet specific requirements. Continuous technological advancement in the field has created a need for new control software that is flexible enough to support the biological researcher with innovative imaging techniques and provide the developer with a solid platform for quickly and easily implementing new extensions. Here, we introduce HelioScan, a software package written in LabVIEW, as a platform serving this dual role. HelioScan is designed as a collection of components that can be flexibly assembled into microscope control software tailored to the particular hardware and functionality requirements. Moreover, HelioScan provides a software framework, within which new functionality can be implemented in a quick and structured manner. A specific HelioScan application assembles at run-time from individual software components, based on user-definable configuration files. Due to its component-based architecture, HelioScan can exploit synergies of multiple developers working in parallel on different components in a community effort. We exemplify the capabilities and versatility of HelioScan by demonstrating several in vivo brain imaging modes, including camera-based intrinsic optical signal imaging for functional mapping of cortical areas, standard two-photon laser-scanning microscopy using galvanometric mirrors, and high-speed in vivo two-photon calcium imaging using either acousto-optic deflectors or a resonant scanner. We recommend HelioScan as a convenient software framework for the in vivo imaging community. PMID:23416135

  19. A computer controlled signal preprocessor for laser fringe anemometer applications

    NASA Technical Reports Server (NTRS)

    Oberle, Lawrence G.

    1987-01-01

    The operation of most commercially available laser fringe anemometer (LFA) counter-processors assumes that adjustments are made to the signal processing independent of the computer used for reducing the data acquired. Not only does the researcher desire a record of these parameters attached to the data acquired, but changes in flow conditions generally require that these settings be changed to improve data quality. Because of this limitation, on-line modification of the data acquisition parameters can be difficult and time consuming. A computer-controlled signal preprocessor has been developed which makes possible this optimization of the photomultiplier signal as a normal part of the data acquisition process. It allows computer control of the filter selection, signal gain, and photo-multiplier voltage. The raw signal from the photomultiplier tube is input to the preprocessor which, under the control of a digital computer, filters the signal and amplifies it to an acceptable level. The counter-processor used at Lewis Research Center generates the particle interarrival times, as well as the time-of-flight of the particle through the probe volume. The signal preprocessor allows computer control of the acquisition of these data.Through the preprocessor, the computer also can control the hand shaking signals for the interface between itself and the counter-processor. Finally, the signal preprocessor splits the pedestal from the signal before filtering, and monitors the photo-multiplier dc current, sends a signal proportional to this current to the computer through an analog to digital converter, and provides an alarm if the current exceeds a predefined maximum. Complete drawings and explanations are provided in the text as well as a sample interface program for use with the data acquisition software.

  20. The analysis of control trajectories using symbolic and database computing

    NASA Technical Reports Server (NTRS)

    Grossman, Robert

    1995-01-01

    This final report comprises the formal semi-annual status reports for this grant for the periods June 30-December 31, 1993, January 1-June 30, 1994, and June 1-December 31, 1994. The research supported by this grant is broadly concerned with the symbolic computation, mixed numeric-symbolic computation, and database computation of trajectories of dynamical systems, especially control systems. A review of work during the report period covers: trajectories and approximating series, the Cayley algebra of trees, actions of differential operators, geometrically stable integration algorithms, hybrid systems, trajectory stores, PTool, and other activities. A list of publications written during the report period is attached.

  1. Computer controlled fluorometer device and method of operating same

    DOEpatents

    Kolber, Z.; Falkowski, P.

    1990-07-17

    A computer controlled fluorometer device and method of operating same, said device being made to include a pump flash source and a probe flash source and one or more sample chambers in combination with a light condenser lens system and associated filters and reflectors and collimators, as well as signal conditioning and monitoring means and a programmable computer means and a software programmable source of background irradiance that is operable according to the method of the invention to rapidly, efficiently and accurately measure photosynthetic activity by precisely monitoring and recording changes in fluorescence yield produced by a controlled series of predetermined cycles of probe and pump flashes from the respective probe and pump sources that are controlled by the computer means. 13 figs.

  2. Computer controlled fluorometer device and method of operating same

    DOEpatents

    Kolber, Zbigniew; Falkowski, Paul

    1990-01-01

    A computer controlled fluorometer device and method of operating same, said device being made to include a pump flash source and a probe flash source and one or more sample chambers in combination with a light condenser lens system and associated filters and reflectors and collimators, as well as signal conditioning and monitoring means and a programmable computer means and a software programmable source of background irradiance that is operable according to the method of the invention to rapidly, efficiently and accurately measure photosynthetic activity by precisely monitoring and recording changes in fluorescence yield produced by a controlled series of predetermined cycles of probe and pump flashes from the respective probe and pump sources that are controlled by the computer means.

  3. Emotor control: computations underlying bodily resource allocation, emotions, and confidence.

    PubMed

    Kepecs, Adam; Mensh, Brett D

    2015-12-01

    Emotional processes are central to behavior, yet their deeply subjective nature has been a challenge for neuroscientific study as well as for psychiatric diagnosis. Here we explore the relationships between subjective feelings and their underlying brain circuits from a computational perspective. We apply recent insights from systems neuroscience-approaching subjective behavior as the result of mental computations instantiated in the brain-to the study of emotions. We develop the hypothesis that emotions are the product of neural computations whose motor role is to reallocate bodily resources mostly gated by smooth muscles. This "emotor" control system is analagous to the more familiar motor control computations that coordinate skeletal muscle movements. To illustrate this framework, we review recent research on "confidence." Although familiar as a feeling, confidence is also an objective statistical quantity: an estimate of the probability that a hypothesis is correct. This model-based approach helped reveal the neural basis of decision confidence in mammals and provides a bridge to the subjective feeling of confidence in humans. These results have important implications for psychiatry, since disorders of confidence computations appear to contribute to a number of psychopathologies. More broadly, this computational approach to emotions resonates with the emerging view that psychiatric nosology may be best parameterized in terms of disorders of the cognitive computations underlying complex behavior. PMID:26869840

  4. Emotor control: computations underlying bodily resource allocation, emotions, and confidence

    PubMed Central

    Kepecs, Adam; Mensh, Brett D.

    2015-01-01

    Emotional processes are central to behavior, yet their deeply subjective nature has been a challenge for neuroscientific study as well as for psychiatric diagnosis. Here we explore the relationships between subjective feelings and their underlying brain circuits from a computational perspective. We apply recent insights from systems neuroscience—approaching subjective behavior as the result of mental computations instantiated in the brain—to the study of emotions. We develop the hypothesis that emotions are the product of neural computations whose motor role is to reallocate bodily resources mostly gated by smooth muscles. This “emotor” control system is analagous to the more familiar motor control computations that coordinate skeletal muscle movements. To illustrate this framework, we review recent research on “confidence.” Although familiar as a feeling, confidence is also an objective statistical quantity: an estimate of the probability that a hypothesis is correct. This model-based approach helped reveal the neural basis of decision confidence in mammals and provides a bridge to the subjective feeling of confidence in humans. These results have important implications for psychiatry, since disorders of confidence computations appear to contribute to a number of psychopathologies. More broadly, this computational approach to emotions resonates with the emerging view that psychiatric nosology may be best parameterized in terms of disorders of the cognitive computations underlying complex behavior. PMID:26869840

  5. Issues in human/computer control of dexterous remote hands

    NASA Technical Reports Server (NTRS)

    Salisbury, K.

    1987-01-01

    Much research on dexterous robot hands has been aimed at the design and control problems associated with their autonomous operation, while relatively little research has addressed the problem of direct human control. It is likely that these two modes can be combined in a complementary manner yielding more capability than either alone could provide. While many of the issues in mixed computer/human control of dexterous hands parallel those found in supervisory control of traditional remote manipulators, the unique geometry and capabilities of dexterous hands pose many new problems. Among these are the control of redundant degrees of freedom, grasp stabilization and specification of non-anthropomorphic behavior. An overview is given of progress made at the MIT AI Laboratory in control of the Salisbury 3 finger hand, including experiments in grasp planning and manipulation via controlled slip. It is also suggested how we might introduce human control into the process at a variety of functional levels.

  6. Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images

    PubMed Central

    Kim, Jooseong

    2016-01-01

    Objective The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Conclusions Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis. PMID:26877978

  7. Computer-Assisted and Patient-Controlled Sedation Platforms.

    PubMed

    Pambianco, Daniel; Niklewski, Paul

    2016-07-01

    As the number and complexity of endoscopic procedures increase, the role of sedation has been integral in patient and physician satisfaction. This article discusses the advances of computer-assisted and patient-controlled platforms. These computer-assisted and patient-controlled platforms use different anesthetics and analgesics, all with the intent of achieving improved consistency in the level of sedation, appropriate to the needs of patients, while also improving patient safety. These systems have been around for decades; however, few are approved for use in the United States, and several still require further study before broad clinical application. PMID:27372778

  8. Progress Towards Computational Method for Circulation Control Airfoils

    NASA Technical Reports Server (NTRS)

    Swanson, R. C.; Rumsey, C. L.; Anders, S. G.

    2005-01-01

    The compressible Reynolds-averaged Navier-Stokes equations are solved for circulation control airfoil flows. Numerical solutions are computed with both structured and unstructured grid solvers. Several turbulence models are considered, including the Spalart-Allmaras model with and without curvature corrections, the shear stress transport model of Menter, and the k-enstrophy model. Circulation control flows with jet momentum coefficients of 0.03, 0.10, and 0.226 are considered. Comparisons are made between computed and experimental pressure distributions, velocity profiles, Reynolds stress profiles, and streamline patterns. Including curvature effects yields the closest agreement with the measured data.

  9. Morphology and growth pattern of Amazon deep-sea fan: a computer-processed GLORIA side-scan mosaic

    SciTech Connect

    Flood, R.D.; Damuth, J.E.

    1984-04-01

    Deep-sea fans have become increasingly important targets for exploration because of their favorable facies associations. A better understanding of deep-sea fans is needed to successfully exploit these complex sediment bodies. Recent studies of the Amazon fan, using long-range side-scan sonar (GLORIA) and single-channel seismic data, provide an overall view of channel patterns of this fan and demonstrate the relationship between successive channel/levee systems. The digitally collected GLORIA data have been computer processed to produce a mosaic of the fan. Computer processing has corrected the records for slant range and ship navigation, and targets have been enhanced. Many features of the modern fan system are readily apparent on the sonar mosaic. The 1.5 to 0.5-km (5000 to 1600-ft) wide channels meander intensely across the fan with sinuosities up to 2.5. Because of these meanders, the channel gradients decrease regularly across the fan despite changes in regional slope. Other channel-related targets include cutoff meanders, overbank deposits (especially small debris flows), and channel branchings. Other debris flows cover large areas of the fan and override channel/levee systems. Air-gun records show that this fan is built of a series of channel/levee systems that overlay one another. Channels from at least 6 of these systems are visible at the surface now, but apparently only one channel at a time has been active. The length of time needed to build a single channel/levee system is not known, but it appears to be rapid.

  10. Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope.

    PubMed

    Green, Matthew F B; Esat, Taner; Wagner, Christian; Leinen, Philipp; Grötsch, Alexander; Tautz, F Stefan; Temirov, Ruslan

    2014-01-01

    One of the paramount goals in nanotechnology is molecular-scale functional design, which includes arranging molecules into complex structures at will. The first steps towards this goal were made through the invention of the scanning probe microscope (SPM), which put single-atom and single-molecule manipulation into practice for the first time. Extending the controlled manipulation to larger molecules is expected to multiply the potential of engineered nanostructures. Here we report an enhancement of the SPM technique that makes the manipulation of large molecular adsorbates much more effective. By using a commercial motion tracking system, we couple the movements of an operator's hand to the sub-angstrom precise positioning of an SPM tip. Literally moving the tip by hand we write a nanoscale structure in a monolayer of large molecules, thereby showing that our method allows for the successful execution of complex manipulation protocols even when the potential energy surface that governs the interaction behaviour of the manipulated nanoscale object(s) is largely unknown. PMID:25383304

  11. Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope

    PubMed Central

    Green, Matthew F B; Esat, Taner; Wagner, Christian; Leinen, Philipp; Grötsch, Alexander; Tautz, F Stefan

    2014-01-01

    Summary One of the paramount goals in nanotechnology is molecular-scale functional design, which includes arranging molecules into complex structures at will. The first steps towards this goal were made through the invention of the scanning probe microscope (SPM), which put single-atom and single-molecule manipulation into practice for the first time. Extending the controlled manipulation to larger molecules is expected to multiply the potential of engineered nanostructures. Here we report an enhancement of the SPM technique that makes the manipulation of large molecular adsorbates much more effective. By using a commercial motion tracking system, we couple the movements of an operator's hand to the sub-angstrom precise positioning of an SPM tip. Literally moving the tip by hand we write a nanoscale structure in a monolayer of large molecules, thereby showing that our method allows for the successful execution of complex manipulation protocols even when the potential energy surface that governs the interaction behaviour of the manipulated nanoscale object(s) is largely unknown. PMID:25383304

  12. Deconvolution of complex differential scanning calorimetry profiles for protein transitions under kinetic control.

    PubMed

    Toledo-Núñez, Citlali; Vera-Robles, L Iraís; Arroyo-Maya, Izlia J; Hernández-Arana, Andrés

    2016-09-15

    A frequent outcome in differential scanning calorimetry (DSC) experiments carried out with large proteins is the irreversibility of the observed endothermic effects. In these cases, DSC profiles are analyzed according to methods developed for temperature-induced denaturation transitions occurring under kinetic control. In the one-step irreversible model (native → denatured) the characteristics of the observed single-peaked endotherm depend on the denaturation enthalpy and the temperature dependence of the reaction rate constant, k. Several procedures have been devised to obtain the parameters that determine the variation of k with temperature. Here, we have elaborated on one of these procedures in order to analyze more complex DSC profiles. Synthetic data for a heat capacity curve were generated according to a model with two sequential reactions; the temperature dependence of each of the two rate constants involved was determined, according to the Eyring's equation, by two fixed parameters. It was then shown that our deconvolution procedure, by making use of heat capacity data alone, permits to extract the parameter values that were initially used. Finally, experimental DSC traces showing two and three maxima were analyzed and reproduced with relative success according to two- and four-step sequential models. PMID:27402175

  13. Computation of records of streamflow at control structures

    USGS Publications Warehouse

    Collins, Dannie L.

    1977-01-01

    Traditional methods of computing streamflow records on large, low-gradient streams require a continuous record of water-surface slope over a natural channel reach. This slope must be of sufficient magnitude to be accuratly measured with available stage measuring devices. On highly regulated streams, this slope approaches zero during periods of low flow and accurate measurement is difficult. Methods are described to calibrate multipurpose regulating control structures to more accurately compute streamflow records on highly-regulated streams. Hydraulic theory, assuming steady, uniform flow during a computational interval, is described for five different types of flow control. The controls are: Tainter gates, hydraulic turbines, fixed spillways, navigation locks, and crest gates. Detailed calibration procedures are described for the five different controls as well as for several flow regimes for some of the controls. The instrumentation package and computer programs necessary to collect and process the field data are discussed. Two typical calibration procedures and measurement data are presented to illustrate the accuracy of the methods. (Woodard-USGS)

  14. Frequency response modeling and control of flexible structures: Computational methods

    NASA Technical Reports Server (NTRS)

    Bennett, William H.

    1989-01-01

    The dynamics of vibrations in flexible structures can be conventiently modeled in terms of frequency response models. For structural control such models capture the distributed parameter dynamics of the elastic structural response as an irrational transfer function. For most flexible structures arising in aerospace applications the irrational transfer functions which arise are of a special class of pseudo-meromorphic functions which have only a finite number of right half place poles. Computational algorithms are demonstrated for design of multiloop control laws for such models based on optimal Wiener-Hopf control of the frequency responses. The algorithms employ a sampled-data representation of irrational transfer functions which is particularly attractive for numerical computation. One key algorithm for the solution of the optimal control problem is the spectral factorization of an irrational transfer function. The basis for the spectral factorization algorithm is highlighted together with associated computational issues arising in optimal regulator design. Options for implementation of wide band vibration control for flexible structures based on the sampled-data frequency response models is also highlighted. A simple flexible structure control example is considered to demonstrate the combined frequency response modeling and control algorithms.

  15. A computer-aided approach to nonlinear control systhesis

    NASA Technical Reports Server (NTRS)

    Wie, Bong; Anthony, Tobin

    1988-01-01

    The major objective of this project is to develop a computer-aided approach to nonlinear stability analysis and nonlinear control system design. This goal is to be obtained by refining the describing function method as a synthesis tool for nonlinear control design. The interim report outlines the approach by this study to meet these goals including an introduction to the INteractive Controls Analysis (INCA) program which was instrumental in meeting these study objectives. A single-input describing function (SIDF) design methodology was developed in this study; coupled with the software constructed in this study, the results of this project provide a comprehensive tool for design and integration of nonlinear control systems.

  16. Open Sinus Lift Surgery and the Importance of Preoperative Cone-Beam Computed Tomography Scan: A Review

    PubMed Central

    Rahpeyma, Amin; Khajehahmadi, Saeedeh

    2015-01-01

    Open sinus lift surgery is a form of pre-prosthetic surgery for increasing the quality and quantity of bone in the posterior region of the maxilla. Pre-operative assessment of the maxillary sinus is essential for the success of this surgery. PubMed search was carried out in English language literature for open sinus lift surgery and cone-beam computed tomography (CBCT). The results focused on anatomic variants, vascular anatomy, complications, osteotomy/ostectomy window dimensions and thickness of the Schneiderian Membrane. 59 articles were included in this review. Features other than the height and the width of the residual alveolar ridge that should be evaluated in preoperative CBCT scan include the thickness of the lateral maxillary sinus wall, the presence of the alveolar antral artery and its diameter, the maxillary sinus floor width and angulation, irregularity of sinus floor, intimate relation of Schneiderian membrane with the roots of the adjacent teeth, sinus septum, and the quality of subantral bone. Other conditions that occasionally may be observed in special situations are also explained. More than ten parameters should be checked in evaluating CBCT images of paranasal sinuses other than the width and the length of the residual ridge in the posterior region of the maxilla. Each of them may have a significant impact on the results of the open sinus lift surgery. PMID:26435632

  17. Segmentation of large periapical lesions toward dental computer-aided diagnosis in cone-beam CT scans

    NASA Astrophysics Data System (ADS)

    Rysavy, Steven; Flores, Arturo; Enciso, Reyes; Okada, Kazunori

    2008-03-01

    This paper presents an experimental study for assessing the applicability of general-purpose 3D segmentation algorithms for analyzing dental periapical lesions in cone-beam computed tomography (CBCT) scans. In the field of Endodontics, clinical studies have been unable to determine if a periapical granuloma can heal with non-surgical methods. Addressing this issue, Simon et al. recently proposed a diagnostic technique which non-invasively classifies target lesions using CBCT. Manual segmentation exploited in their study, however, is too time consuming and unreliable for real world adoption. On the other hand, many technically advanced algorithms have been proposed to address segmentation problems in various biomedical and non-biomedical contexts, but they have not yet been applied to the field of dentistry. Presented in this paper is a novel application of such segmentation algorithms to the clinically-significant dental problem. This study evaluates three state-of-the-art graph-based algorithms: a normalized cut algorithm based on a generalized eigen-value problem, a graph cut algorithm implementing energy minimization techniques, and a random walks algorithm derived from discrete electrical potential theory. In this paper, we extend the original 2D formulation of the above algorithms to segment 3D images directly and apply the resulting algorithms to the dental CBCT images. We experimentally evaluate quality of the segmentation results for 3D CBCT images, as well as their 2D cross sections. The benefits and pitfalls of each algorithm are highlighted.

  18. Rapid protein structure classification using one-dimensional structure profiles on the bioSCAN parallel computer.

    PubMed

    Hoffman, D L; Laiter, S; Singh, R K; Vaisman, I I; Tropsha, A

    1995-12-01

    Rapid growth of protein structures database in recent years requires an effective approach for objective comparison and classification of deposited protein structures. We describe a novel method for structure comparison and classification based on the alignment of one-dimensional structure profiles. These profiles are obtained by calculating the OCCO pseudodihedral angles (formed by O-C-C-O atoms of carbonyl groups of consecutive amino acid residues) from protein three-dimensional coordinates. These angle measurements are then converted into a 24 letter alphabet, and the protein structures are represented by sequences of letter from this alphabet. The BioSCAN parallel computer, designed for primary sequence alignment, is used to rapidly align and classify these one-dimensional structure profiles. We have developed and implemented weighted scoring matrix to identify structural classes based on commonly found structural motifs. The results of our experiments are in good agreement with the traditional protein structure classification schemes. One-dimensional structure profiles significantly improve efficiency of structure comparison and classification. PMID:8808584

  19. Computation of robustly stabilizing PID controllers for interval systems.

    PubMed

    Matušů, Radek; Prokop, Roman

    2016-01-01

    The paper is focused on the computation of all possible robustly stabilizing Proportional-Integral-Derivative (PID) controllers for plants with interval uncertainty. The main idea of the proposed method is based on Tan's (et al.) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space. Refinement of the existing method by consideration of 16 segment plants instead of 16 Kharitonov plants provides an elegant and efficient tool for finding all robustly stabilizing PID controllers for an interval system. The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example in which the uncertain mathematical model of an experimental oblique wing aircraft is robustly stabilized. PMID:27350931

  20. Closed-loop control of a 2-D mems micromirror with sidewall electrodes for a laser scanning microscope system

    NASA Astrophysics Data System (ADS)

    Chen, Hui; Chen, Albert; Jie Sun, Wei; Sun, Zhen Dong; Yeow, John TW

    2016-01-01

    This article presents the development and implementation of a robust nonlinear control scheme for a 2-D micromirror-based laser scanning microscope system. The presented control scheme, built around sliding mode control approach and augmented an adaptive algorithm, is proposed to improve the tracking accuracy in presence of cross-axis effect. The closed-loop controlled imaging system is developed through integrating a 2-D micromirror with sidewall electrodes (SW), a laser source, NI field-programmable gate array (FPGA) hardware, the optics, position sensing detector (PSD) and photo detector (PD). The experimental results demonstrated that the proposed scheme is able to achieve accurate tracking of a reference triangular signal. Compared with open-loop control, the scanning performance is significantly improved, and a better 2-D image is obtained using the micromirror with the proposed scheme.

  1. Techniques used for the analysis of oculometer eye-scanning data obtained from an air traffic control display

    NASA Technical Reports Server (NTRS)

    Crawford, Daniel J.; Burdette, Daniel W.; Capron, William R.

    1993-01-01

    The methodology and techniques used to collect and analyze look-point position data from a real-time ATC display-format comparison experiment are documented. That study compared the delivery precision and controller workload of three final approach spacing aid display formats. Using an oculometer, controller lookpoint position data were collected, associated with gaze objects (e.g., moving aircraft) on the ATC display, and analyzed to determine eye-scan behavior. The equipment involved and algorithms for saving, synchronizing with the ATC simulation output, and filtering the data are described. Target (gaze object) and cross-check scanning identification algorithms are also presented. Data tables are provided of total dwell times, average dwell times, and cross-check scans. Flow charts, block diagrams, file record descriptors, and source code are included. The techniques and data presented are intended to benefit researchers in other studies that incorporate non-stationary gaze objects and oculometer equipment.

  2. Control of Computer Room Air Conditioning using IT Equipment Sensors

    SciTech Connect

    Bell, Geoffrey C.; Storey, Bill; Patterson, Michael K.

    2009-09-30

    The goal of this demonstration was to show how sensors in IT equipment could be accessed and used to directly control computer room air conditioning. The data provided from the sensors is available on the IT network and the challenge for this project was to connect this information to the computer room air handler's control system. A control strategy was developed to enable separate control of the chilled water flow and the fans in the computer room air handlers. By using these existing sensors in the IT equipment, an additional control system is eliminated (or could be redundant) and optimal cooling can be provided saving significant energy. Using onboard server temperature sensors will yield significant energy reductions in data centers. Intel hosted the demonstration in its Santa Clara, CA data center. Intel collaborated with IBM, HP, Emerson, Wunderlich-Malec Engineers, FieldServer Technologies, and LBNL to install the necessary components and develop the new control scheme. LBNL also validated the results of the demonstration.

  3. Temporal Evolution of Spatial Computations for Visuomotor Control.

    PubMed

    Franklin, David W; Reichenbach, Alexandra; Franklin, Sae; Diedrichsen, Jörn

    2016-02-24

    Goal-directed reaching movements are guided by visual feedback from both target and hand. The classical view is that the brain extracts information about target and hand positions from a visual scene, calculates a difference vector between them, and uses this estimate to control the movement. Here we show that during fast feedback control, this computation is not immediate, but evolves dynamically over time. Immediately after a change in the visual scene, the motor system generates independent responses to the errors in hand and target location. Only about 200 ms later, the changes in target and hand positions are combined appropriately in the response, slowly converging to the true difference vector. Therefore, our results provide evidence for the temporal evolution of spatial computations in the human visuomotor system, in which the accurate difference vector computation is first estimated by a fast approximation. PMID:26911681

  4. Computer-Numerical-Control and the EMCO Compact 5 Lathe.

    ERIC Educational Resources Information Center

    Mullen, Frank M.

    This laboratory manual is intended for use in teaching computer-numerical-control (CNC) programming using the Emco Maier Compact 5 Lathe. Developed for use at the postsecondary level, this material contains a short introduction to CNC machine tools. This section covers CNC programs, CNC machine axes, and CNC coordinate systems. The following…

  5. Computer used to program numerically controlled milling machine

    NASA Technical Reports Server (NTRS)

    Harris, T. C.

    1967-01-01

    Computer program automatically directs a numerically controlled milling machine through a series of cutting and trimming actions. It accepts engineering data points, passes smooth curve segments through the points, breaks the resulting curves into a series of closely spaced points, and transforms these points into the form required by the mechanism.

  6. Computer codes for evaluation of control room habitability (HABIT)

    SciTech Connect

    Stage, S.A.

    1996-06-01

    This report describes the Computer Codes for Evaluation of Control Room Habitability (HABIT). HABIT is a package of computer codes designed to be used for the evaluation of control room habitability in the event of an accidental release of toxic chemicals or radioactive materials. Given information about the design of a nuclear power plant, a scenario for the release of toxic chemicals or radionuclides, and information about the air flows and protection systems of the control room, HABIT can be used to estimate the chemical exposure or radiological dose to control room personnel. HABIT is an integrated package of several programs that previously needed to be run separately and required considerable user intervention. This report discusses the theoretical basis and physical assumptions made by each of the modules in HABIT and gives detailed information about the data entry windows. Sample runs are given for each of the modules. A brief section of programming notes is included. A set of computer disks will accompany this report if the report is ordered from the Energy Science and Technology Software Center. The disks contain the files needed to run HABIT on a personal computer running DOS. Source codes for the various HABIT routines are on the disks. Also included are input and output files for three demonstration runs.

  7. A COMPUTER CONTROL AND ACQUISITION SYSTEM FOR ATOMIC ABSORPTION DATA

    EPA Science Inventory

    A system is presented that controls and acquires data from a Perkin-Elmer 603 or similar atomic absorption spectrophotometer operating in the flame mode and equipped with a 200 place auto-sampler. The hardware consists of a PDP11 computer with minimum peripheral equipment and a s...

  8. ANL computer controlled target storage system: Status report

    SciTech Connect

    Klimczak, G.W.; Nardi, B.G.; Travis, D.J.

    1986-01-01

    Design and operation of an isotopic target storage system is described. Due to the cost and effort associated with nuclear target production, it is necessary to protect them. The storage system described was designed to protect up to 90 hydroscopic and readily oxidizing targets under vacuum of 10/sup -6/ torr. The computer controller maintains system integrity during normal use and emergency situations. (JDH)

  9. View southeast of computer controlled energy monitoring system. System replaced ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View southeast of computer controlled energy monitoring system. System replaced strip chart recorders and other instruments under the direct observation of the load dispatcher. - Thirtieth Street Station, Load Dispatch Center, Thirtieth & Market Streets, Railroad Station, Amtrak (formerly Pennsylvania Railroad Station), Philadelphia, Philadelphia County, PA

  10. 8. DETAIL OF COMPUTER SCREEN AND CONTROL BOARDS: LEFT SCREEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. DETAIL OF COMPUTER SCREEN AND CONTROL BOARDS: LEFT SCREEN TRACKS RESIDUAL CHLORINE; INDICATES AMOUNT OF SUNLIGHT WHICH ENABLES OPERATOR TO ESTIMATE NEEDED CHLORINE; CENTER SCREEN SHOWS TURNOUT STRUCTURES; RIGHT SCREEN SHOWS INDICATORS OF ALUMINUM SULFATE TANK FARM. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

  11. Computer numerical control grinding of spiral bevel gears

    NASA Technical Reports Server (NTRS)

    Scott, H. Wayne

    1991-01-01

    The development of Computer Numerical Control (CNC) spiral bevel gear grinding has paved the way for major improvement in the production of precision spiral bevel gears. The object of the program was to decrease the setup, maintenance of setup, and pattern development time by 50 percent of the time required on conventional spiral bevel gear grinders. Details of the process are explained.

  12. Three-dimensional reconstructions from computed tomographic scans on smartphones and tablets: a simple tutorial for the ward and operating room using public domain software.

    PubMed

    Ketoff, Serge; Khonsari, Roman Hossein; Schouman, Thomas; Bertolus, Chloé

    2014-11-01

    Handling 3-dimensional reconstructions of computed tomographic scans on portable devices is problematic because of the size of the Digital Imaging and Communications in Medicine (DICOM) stacks. The authors provide a user-friendly method allowing the production, transfer, and sharing of good-quality 3-dimensional reconstructions on smartphones and tablets. PMID:25438270

  13. Human-computer interface including haptically controlled interactions

    DOEpatents

    Anderson, Thomas G.

    2005-10-11

    The present invention provides a method of human-computer interfacing that provides haptic feedback to control interface interactions such as scrolling or zooming within an application. Haptic feedback in the present method allows the user more intuitive control of the interface interactions, and allows the user's visual focus to remain on the application. The method comprises providing a control domain within which the user can control interactions. For example, a haptic boundary can be provided corresponding to scrollable or scalable portions of the application domain. The user can position a cursor near such a boundary, feeling its presence haptically (reducing the requirement for visual attention for control of scrolling of the display). The user can then apply force relative to the boundary, causing the interface to scroll the domain. The rate of scrolling can be related to the magnitude of applied force, providing the user with additional intuitive, non-visual control of scrolling.

  14. Overview of computational control research at UT Austin

    NASA Technical Reports Server (NTRS)

    Bong, Wie

    1989-01-01

    An overview of current research activities at UT Austin is presented to discuss certain technical issues in the following areas: (1) Computer-Aided Nonlinear Control Design: In this project, the describing function method is employed for the nonlinear control analysis and design of a flexible spacecraft equipped with pulse modulated reaction jets. INCA program has been enhanced to allow the numerical calculation of describing functions as well as the nonlinear limit cycle analysis capability in the frequency domain; (2) Robust Linear Quadratic Gaussian (LQG) Compensator Synthesis: Robust control design techniques and software tools are developed for flexible space structures with parameter uncertainty. In particular, an interactive, robust multivariable control design capability is being developed for INCA program; and (3) LQR-Based Autonomous Control System for the Space Station: In this project, real time implementation of LQR-based autonomous control system is investigated for the space station with time-varying inertias and with significant multibody dynamic interactions.

  15. Are Prenatal Ultrasound Scans Associated with the Autism Phenotype? Follow-Up of a Randomised Controlled Trial

    ERIC Educational Resources Information Center

    Stoch, Yonit K.; Williams, Cori J.; Granich, Joanna; Hunt, Anna M.; Landau, Lou I.; Newnham, John P.; Whitehouse, Andrew J. O.

    2012-01-01

    An existing randomised controlled trial was used to investigate whether multiple ultrasound scans may be associated with the autism phenotype. From 2,834 single pregnancies, 1,415 were selected at random to receive ultrasound imaging and continuous wave Doppler flow studies at five points throughout pregnancy (Intensive) and 1,419 to receive a…

  16. Computer controlled techniques for high emission density mapping of thermionic cathodes

    NASA Astrophysics Data System (ADS)

    Gibson, J. W.; Thomas, R. E.

    1985-12-01

    Some of the techniques commonly used (e.g. SLEEP and thermionic emission microscope) for measuring emission or work function uniformity of thermionic cathode surfaces require the use of very low or near zero current densities, thus the cathode is characterized at current densities and temperatures much lower than that of a normally operating cathode. The system reported on here uses a high voltage pulse technique and is capable of measuring emission densities in the range 1 to 80 A/cm 2 at normal cathode operating temperatures. The cathode surface is scanned with an anode having a 0.025 mm aperture whose position is controlled by computer operated stepping motors. The current through the aperture to a collector electrode is measured using a sample-and-hold amplifier. Pulsing and sampling are computer synchronized with the scanning, and data for each pulse are accumulated and can be processed and displayed in several ways using the computer, including a detailed "three-dimensional" map of either the electron emission density or work function variations. The entire surface of the cathode or any portion of it can be mapped in steps as small as 0.001 mm (1μm), but typically steps of 5-100 μm were used. Measurements are presented illustrating the uniformity or nonuniformity of the electron emission densities and work functions for type-B and type-M cathodes.

  17. Closed loop computer control for an automatic transmission

    DOEpatents

    Patil, Prabhakar B.

    1989-01-01

    In an automotive vehicle having an automatic transmission that driveably connects a power source to the driving wheels, a method to control the application of hydraulic pressure to a clutch, whose engagement produces an upshift and whose disengagement produces a downshift, the speed of the power source, and the output torque of the transmission. The transmission output shaft torque and the power source speed are the controlled variables. The commanded power source torque and commanded hydraulic pressure supplied to the clutch are the control variables. A mathematical model is formulated that describes the kinematics and dynamics of the powertrain before, during and after a gear shift. The model represents the operating characteristics of each component and the structural arrangement of the components within the transmission being controlled. Next, a close loop feedback control is developed to determine the proper control law or compensation strategy to achieve an acceptably smooth gear ratio change, one in which the output torque disturbance is kept to a minimum and the duration of the shift is minimized. Then a computer algorithm simulating the shift dynamics employing the mathematical model is used to study the effects of changes in the values of the parameters established from a closed loop control of the clutch hydraulic and the power source torque on the shift quality. This computer simulation is used also to establish possible shift control strategies. The shift strategies determined from the prior step are reduced to an algorithm executed by a computer to control the operation of the power source and the transmission.

  18. System for computer controlled shifting of an automatic transmission

    DOEpatents

    Patil, Prabhakar B.

    1989-01-01

    In an automotive vehicle having an automatic transmission that driveably connects a power source to the driving wheels, a method to control the application of hydraulic pressure to a clutch, whose engagement produces an upshift and whose disengagement produces a downshift, the speed of the power source, and the output torque of the transmission. The transmission output shaft torque and the power source speed are the controlled variables. The commanded power source torque and commanded hydraulic pressure supplied to the clutch are the control variables. A mathematical model is formulated that describes the kinematics and dynamics of the powertrain before, during and after a gear shift. The model represents the operating characteristics of each component and the structural arrangement of the components within the transmission being controlled. Next, a close loop feedback control is developed to determine the proper control law or compensation strategy to achieve an acceptably smooth gear ratio change, one in which the output torque disturbance is kept to a minimum and the duration of the shift is minimized. Then a computer algorithm simulating the shift dynamics employing the mathematical model is used to study the effects of changes in the values of the parameters established from a closed loop control of the clutch hydraulic and the power source torque on the shift quality. This computer simulation is used also to establish possible shift control strategies. The shift strategies determine from the prior step are reduced to an algorithm executed by a computer to control the operation of the power source and the transmission.

  19. Soft Real-Time PID Control on a VME Computer

    NASA Technical Reports Server (NTRS)

    Karayan, Vahag; Sander, Stanley; Cageao, Richard

    2007-01-01

    microPID (uPID) is a computer program for real-time proportional + integral + derivative (PID) control of a translation stage in a Fourier-transform ultraviolet spectrometer. microPID implements a PID control loop over a position profile at sampling rate of 8 kHz (sampling period 125microseconds). The software runs in a strippeddown Linux operating system on a VersaModule Eurocard (VME) computer operating in real-time priority queue using an embedded controller, a 16-bit digital-to-analog converter (D/A) board, and a laser-positioning board (LPB). microPID consists of three main parts: (1) VME device-driver routines, (2) software that administers a custom protocol for serial communication with a control computer, and (3) a loop section that obtains the current position from an LPB-driver routine, calculates the ideal position from the profile, and calculates a new voltage command by use of an embedded PID routine all within each sampling period. The voltage command is sent to the D/A board to control the stage. microPID uses special kernel headers to obtain microsecond timing resolution. Inasmuch as microPID implements a single-threaded process and all other processes are disabled, the Linux operating system acts as a soft real-time system.

  20. Note: Computer controlled rotation mount for large diameter optics

    NASA Astrophysics Data System (ADS)

    Rakonjac, Ana; Roberts, Kris O.; Deb, Amita B.; Kjærgaard, Niels

    2013-02-01

    We describe the construction of a motorized optical rotation mount with a 40 mm clear aperture. The device is used to remotely control the power of large diameter laser beams for a magneto-optical trap. A piezo-electric ultrasonic motor on a printed circuit board provides rotation with a precision better than 0.03° and allows for a very compact design. The rotation unit is controlled from a computer via serial communication, making integration into most software control platforms straightforward.

  1. View northeast of a microchip based computer control system installed ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View northeast of a microchip based computer control system installed in the early 1980's to replace Lamokin Tower, at center of photograph; panels 1 and 2 at right of photograph are part of main supervisory board; panel 1 controlled Allen Lane sub-station #7; responsiblity for this portion of the system was transferred to southeast Pennsylvania transit authority (septa) in 1985; panel 2 at extreme right controls catenary switches in a coach storage yard adjacent to the station - Thirtieth Street Station, Power Director Center, Thirtieth & Market Streets in Amtrak Railroad Station, Philadelphia, Philadelphia County, PA

  2. VPI - VIBRATION PATTERN IMAGER: A CONTROL AND DATA ACQUISITION SYSTEM FOR SCANNING LASER VIBROMETERS

    NASA Technical Reports Server (NTRS)

    Rizzi, S. A.

    1994-01-01

    The Vibration Pattern Imager (VPI) system was designed to control and acquire data from laser vibrometer sensors. The PC computer based system uses a digital signal processing (DSP) board and an analog I/O board to control the sensor and to process the data. The VPI system was originally developed for use with the Ometron VPI Sensor (Ometron Limited, Kelvin House, Worsley Bridge Road, London, SE26 5BX, England), but can be readily adapted to any commercially available sensor which provides an analog output signal and requires analog inputs for control of mirror positioning. VPI's graphical user interface allows the operation of the program to be controlled interactively through keyboard and mouse-selected menu options. The main menu controls all functions for setup, data acquisition, display, file operations, and exiting the program. Two types of data may be acquired with the VPI system: single point or "full field". In the single point mode, time series data is sampled by the A/D converter on the I/O board at a user-defined rate for the selected number of samples. The position of the measuring point, adjusted by mirrors in the sensor, is controlled via a mouse input. In the "full field" mode, the measurement point is moved over a user-selected rectangular area with up to 256 positions in both x and y directions. The time series data is sampled by the A/D converter on the I/O board and converted to a root-mean-square (rms) value by the DSP board. The rms "full field" velocity distribution is then uploaded for display and storage. VPI is written in C language and Texas Instruments' TMS320C30 assembly language for IBM PC series and compatible computers running MS-DOS. The program requires 640K of RAM for execution, and a hard disk with 10Mb or more of disk space is recommended. The program also requires a mouse, a VGA graphics display, a Four Channel analog I/O board (Spectrum Signal Processing, Inc.; Westborough, MA), a break-out box and a Spirit-30 board (Sonitech

  3. Controlling Combinatorial Complexity in Software and Malware Behavior Computation

    SciTech Connect

    Pleszkoch, Mark G; Linger, Richard C

    2015-01-01

    Virtually all software is out of intellectual control in that no one knows its full behavior. Software Behavior Computation (SBC) is a new technology for understanding everything software does. SBC applies the mathematics of denotational semantics implemented by function composition in Functional Trace Tables (FTTs) to compute the behavior of programs, expressed as disjoint cases of conditional concurrent assignments. In some circumstances, combinatorial explosions in the number of cases can occur when calculating the behavior of sequences of multiple branching structures. This paper describes computational methods that avoid combinatorial explosions. The predicates that control branching structures such as ifthenelses can be organized into three categories: 1) Independent, resulting in no behavior case explosion, 2) Coordinated, resulting in two behavior cases, or 3) Goaloriented, with potential exponential growth in the number of cases. Traditional FTT-based behavior computation can be augmented by two additional computational methods, namely, Single-Value Function Abstractions (SVFAs) and, introduced in this paper, Relational Trace Tables (RTTs). These methods can be applied to the three predicate categories to avoid combinatorial growth in behavior cases while maintaining mathematical correctness.

  4. The Use of Passwords for Controlled Access to Computer Resources. Computer Science & Technology.

    ERIC Educational Resources Information Center

    Wood, Helen M.

    This paper considers the generation of passwords and their effective application to the problem of controlling access to computer resources. After describing the need for and uses of passwords, password schemes are categorized according to selection technique, lifetime, physical characteristics, and information content. Password protection, both…

  5. Personal Computer Based Controller For Switched Reluctance Motor Drives

    NASA Astrophysics Data System (ADS)

    Mang, X.; Krishnan, R.; Adkar, S.; Chandramouli, G.

    1987-10-01

    Th9, switched reluctance motor (SRM) has recently gained considerable attention in the variable speed drive market. Two important factors that have contributed to this are, the simplicity of construction and the possibility of developing low cost con-trollers with minimum number of switching devices in the drive circuits. This is mainly due to the state-of-art of the present digital circuits technology and the low cost of switching devices. The control of this motor drive is under research. Optimized performance of the SRM motor drive is very dependent on the integration of the controller, converter and the motor. This research on system integration involves considerable changes in the control algorithms and their implementation. A Personal computer (PC) based controller is very appropriate for this purpose. Accordingly, the present paper is concerned with the design of a PC based controller for a SRM. The PC allows for real-time microprocessor control with the possibility of on-line system parameter modifications. Software reconfiguration of this controller is easier than a hardware based controller. User friendliness is a natural consequence of such a system. Considering the low cost of PCs, this controller will offer an excellent cost-effective means of studying the control strategies for the SRM drive intop greater detail than in the past.

  6. Computerized Automated Quantification of Subcutaneous and Visceral Adipose Tissue From Computed Tomography Scans: Development and Validation Study

    PubMed Central

    Kim, Young Jae; Park, Ji Won; Kim, Jong Wan; Park, Chan-Soo; Gonzalez, John Paul S; Lee, Seung Hyun

    2016-01-01

    Background Computed tomography (CT) is often viewed as one of the most accurate methods for measuring visceral adipose tissue (VAT). However, measuring VAT and subcutaneous adipose tissue (SAT) from CT is a time-consuming and tedious process. Thus, evaluating patients’ obesity levels during clinical trials using CT scans is both cumbersome and limiting. Objective To describe an image-processing-based and automated method for measuring adipose tissue in the entire abdominal region. Methods The method detects SAT and VAT levels using a separation mask based on muscles of the human body. The separation mask is the region that minimizes the unnecessary space between a closed path and muscle area. In addition, a correction mask, based on bones, corrects the error in VAT. Results To validate the method, the volume of total adipose tissue (TAT), SAT, and VAT were measured for a total of 100 CTs using the automated method, and the results compared with those from manual measurements obtained by 2 experts. Dice’s similarity coefficients (DSCs) between the first manual measurement and the automated result for TAT, SAT, and VAT are 0.99, 0.98, and 0.97, respectively. The DSCs between the second manual measurement and the automated result for TAT, SAT, and VAT are 0.98, 0.98, and 0.97, respectively. Moreover, intraclass correlation coefficients (ICCs) between the automated method and the results of the manual measurements indicate high reliability as the ICCs for the items are all .99 (P<.001). Conclusions The results described in this paper confirm the accuracy and reliability of the proposed method. The method is expected to be both convenient and useful in the clinical evaluation and study of obesity in patients who require SAT and VAT measurements. PMID:26846251

  7. Analysis of β-tricalcium phosphate granules prepared with different formulations by nano-computed tomography and scanning electron microscopy.

    PubMed

    Terranova, Lisa; Libouban, Hélène; Mallet, Romain; Chappard, Daniel

    2015-12-01

    Among biomaterials used for filling bone defects, beta-tricalcium phosphate (β-TCP) is suitable in non-bearing bones, particularly in dental implantology, oral and maxillofacial surgery. When β-TCP granules are placed in a bone defect, they occupy the void 3D volume. Little is known about the 3D arrangement of the granules, which depends on the nature and size of the granules. The aim of this study was to examine the 3D architecture of porous β-TCP granules. Granules were prepared with different concentrations of β-TCP powder in slurry (10, 11, 15, 18, 21, and 25 g of β-TCP powder in distilled water). Granules were prepared by the polyurethane foam method. They were analyzed by nano-computed tomography (nanoCT) and compared with scanning electron microscopy (SEM). Commercial granules of hydroxyapatite-β-TCP prepared by the same methodology were also used. The outer and inner architectures of the granules were shown by nanoCT which evidenced macroporosity, internal porosity and microporosity between the sintered grains. Macroporosity was reduced at high concentration and conversely, numerous concave surfaces were observed. Internal porosity, related to the sublimation of the polyurethane foam, was present in all the granules. Microporosity at the grain joints was evidenced by SEM and on 2D nanoCT sections. Granules presented a heterogeneous aspect due to the different mineralization degree of the sintered powder grains in the β-TCP granules; the difference between hydroxyapatite and β-TCP was also evidenced. NanoCT is an interesting method to analyze the fine morphology of biomaterials with a resolution close to synchrotron and better than microcomputed tomography. PMID:25899237

  8. Measurement of endotracheal tube secretions volume by micro computed tomography (MicroCT) scan: an experimental and clinical study

    PubMed Central

    2014-01-01

    Background Biofilm accumulates within the endotracheal tube (ETT) early after intubation. Contaminated secretions in the ETT are associated with increased risk for microbial dissemination in the distal airways and increased resistance to airflow. We evaluated the effectiveness of micro computed tomography (MicroCT) for the quantification of ETT inner volume reduction in critically ill patients. Methods We injected a known amount of gel into unused ETT to simulate secretions. We calculated the volume of gel analyzing MicroCT scans for a length of 20 cm. We then collected eleven ETTs after extubation of critically ill patients, recording clinical and demographical data. We assessed the amount of secretions by MicroCT and obtained ETT microbiological cultures. Results Gel volumes assessed by MicroCT strongly correlated with injected gel volumes (p < 0.001, r2 = 0.999). MicroCT revealed the accumulation of secretions on all the ETTs (median 0.154, IQR:0.02-0.837 mL), corresponding to an average cross-sectional area reduction of 1.7%. The amount of secretions inversely correlated with patients’ age (p = 0.011, rho = −0.727) but not with days of intubation, SAPS2, PaO2/FiO2 assessed on admission. Accumulation of secretions was higher in the cuff region (p = 0.003). Microbial growth occurred in cultures from 9/11 ETTs, and did not correlate with secretions amount. In 7/11 cases the same microbes were identified also in tracheal aspirates. Conclusions MicroCT appears as a feasible and precise technique to measure volume of secretions within ETTs after extubation. In patients, secretions tend to accumulate in the cuff region, with high variability among patients. PMID:24678963

  9. Parallel and vector computation for stochastic optimal control applications

    NASA Technical Reports Server (NTRS)

    Hanson, F. B.

    1989-01-01

    A general method for parallel and vector numerical solutions of stochastic dynamic programming problems is described for optimal control of general nonlinear, continuous time, multibody dynamical systems, perturbed by Poisson as well as Gaussian random white noise. Possible applications include lumped flight dynamics models for uncertain environments, such as large scale and background random atmospheric fluctuations. The numerical formulation is highly suitable for a vector multiprocessor or vectorizing supercomputer, and results exhibit high processor efficiency and numerical stability. Advanced computing techniques, data structures, and hardware help alleviate Bellman's curse of dimensionality in dynamic programming computations.

  10. Temporal Evolution of Spatial Computations for Visuomotor Control

    PubMed Central

    Reichenbach, Alexandra; Franklin, Sae; Diedrichsen, Jörn

    2016-01-01

    Goal-directed reaching movements are guided by visual feedback from both target and hand. The classical view is that the brain extracts information about target and hand positions from a visual scene, calculates a difference vector between them, and uses this estimate to control the movement. Here we show that during fast feedback control, this computation is not immediate, but evolves dynamically over time. Immediately after a change in the visual scene, the motor system generates independent responses to the errors in hand and target location. Only about 200 ms later, the changes in target and hand positions are combined appropriately in the response, slowly converging to the true difference vector. Therefore, our results provide evidence for the temporal evolution of spatial computations in the human visuomotor system, in which the accurate difference vector computation is first estimated by a fast approximation. SIGNIFICANCE STATEMENT The dominant view regarding the neural control of reaching is that the visuomotor system controls movement based on the difference vector—the difference between the positions of the hand and target. We directly test this theory by measuring the responses to visual perturbations over a large range of possible variations in both target and hand displacements. By modeling the nonlinearity of the feedback response, we were able to reveal the temporal evolution of the underlying computations. The visuomotor system first uses an approximation to the difference vector computation, simply combining the nonlinear responses to cursor and target displacements, only arriving at the correct difference vector calculation 200 ms later. PMID:26911681

  11. 68Ga-DOTATATE positron emission tomography/computed tomography scan in the detection of bone metastases in pediatric neuroendocrine tumors

    PubMed Central

    Goel, Reema; Shukla, Jaya; Bansal, Deepak; Sodhi, Kushaljit; Bhattacharya, Anish; Marwaha, Ram Kumar; Mittal, Bhagwant Rai

    2014-01-01

    Aim: The aim of this study is to evaluate the role of 68Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) scan for the detection of bone metastases in pediatric neuroendocrine tumors (NETs) and to compare it with CT scan. Materials and Methods: A total of 30 patients (18 were males and 12 were females; age range: 1-18 years; mean age 7.6 years) with histologically confirmed NETs referred to our department were retrospectively analyzed. All patients underwent 68Ga-DOTATATE PET/CT scan at the time of diagnosis for primary staging. Contrast enhanced CT (CECT) performed at the time of PET scan acquisition was used for comparison with PET data. Imaging results were analyzed on a per-patient and on a per-lesion basis. Clinical follow-up of all patients and repeat PET/CT imaging (n = 10) was taken as the reference standard. Results: Out of the 30 patients, 17 had no evidence of bone metastases on any imaging modality or on clinical follow-up while the rest of 13 patients showed evidence of bone metastases (nine showing positivity both on 68Ga-DOTATATE PET and CT scan while four showing positivity only on 68Ga-DOTATATE PET). Compared with CT scan, 68Ga-DOTATATE PET detected bone metastases at a significantly higher rate (P = 0.0039). On a per lesion analysis, out of a total of 225 lesions detected by 68Ga-DOTATATE PET, only 84 lesions could be detected by CT scan. Conclusion: 68Ga-DOTATATE PET/CT scan is more useful than CECT scan for the early detection of bone metastases in pediatric NETs. PMID:24591776

  12. Application of computer algebra-techniques to metabolic control analysis.

    PubMed

    Bayram, Mustafa; Celik, Ercan

    2003-05-01

    For practical purposes the calculation of rate constants is not particularly valuable, since their physical significance is not clear. Of greater practical use are metabolic control coefficients and elasticities. Given the definition of the flux control coefficients C(E)(J), concentration control coefficient C(E)(X) and elasticity epsilon (X)(v(1)). We can calculate symbolic formulae for these using computer algebra-techniques. These are then functions of V(max), K(m), K(i) enzyme and concentrations. Having derived estimates of V(max), K(m), K(i) using the fitting method we can then calculate values of the control coefficients and elasticities. Furthermore we can calculate the metabolic control parameters using symbolic values for the conventional kinetic parameters. Using these we have verified the summation and connectivity theorems. This is a useful cross check on the reliability of the calculations. PMID:12821311

  13. Computer-aided analysis of airway trees in micro-CT scans of ex vivo porcine lung tissue.

    PubMed

    Bauer, Christian; Adam, Ryan; Stoltz, David A; Beichel, Reinhard R

    2012-12-01

    We present a highly automated approach to obtain detailed structural models of airway trees from ex vivo porcine lung tissue imaged with a high resolution micro-CT scanner. Such information is an important prerequisite to systematically study models of lung disease that affect airway morphology. The method initially identifies all tubular airway-like structures in the lung. In a second processing step, these structures are grouped into a connected airway tree by utilizing prior knowledge about the airway trees branching pattern. The method was evaluated on 12 micro-CT scans from four tracheal lobes of piglets imaged at three different inflation levels. For this study, two control piglets and two cystic fibrosis piglets were used. For systematic validation of our approach, an airway nomenclature was developed for the pig airway tree. Out of more than 3500 airway tree segments assessed during evaluation, 88.45% were correctly identified by the method. No false positive airway branches were found. A detailed performance analysis for different airway tree hierarchy levels, lung inflation levels and piglets with/without cystic fibrosis is presented in the paper. PMID:22959430

  14. Fault tolerant computer control for a Maglev transportation system

    NASA Astrophysics Data System (ADS)

    Lala, Jaynarayan H.; Nagle, Gail A.; Anagnostopoulos, George

    1994-05-01

    Magnetically levitated (Maglev) vehicles operating on dedicated guideways at speeds of 500 km/hr are an emerging transportation alternative to short-haul air and high-speed rail. They have the potential to offer a service significantly more dependable than air and with less operating cost than both air and high-speed rail. Maglev transportation derives these benefits by using magnetic forces to suspend a vehicle 8 to 200 mm above the guideway. Magnetic forces are also used for propulsion and guidance. The combination of high speed, short headways, stringent ride quality requirements, and a distributed offboard propulsion system necessitates high levels of automation for the Maglev control and operation. Very high levels of safety and availability will be required for the Maglev control system. This paper describes the mission scenario, functional requirements, and dependability and performance requirements of the Maglev command, control, and communications system. A distributed hierarchical architecture consisting of vehicle on-board computers, wayside zone computers, a central computer facility, and communication links between these entities was synthesized to meet the functional and dependability requirements on the maglev. Two variations of the basic architecture are described: the Smart Vehicle Architecture (SVA) and the Zone Control Architecture (ZCA). Preliminary dependability modeling results are also presented.

  15. Fault tolerant computer control for a Maglev transportation system

    NASA Technical Reports Server (NTRS)

    Lala, Jaynarayan H.; Nagle, Gail A.; Anagnostopoulos, George

    1994-01-01

    Magnetically levitated (Maglev) vehicles operating on dedicated guideways at speeds of 500 km/hr are an emerging transportation alternative to short-haul air and high-speed rail. They have the potential to offer a service significantly more dependable than air and with less operating cost than both air and high-speed rail. Maglev transportation derives these benefits by using magnetic forces to suspend a vehicle 8 to 200 mm above the guideway. Magnetic forces are also used for propulsion and guidance. The combination of high speed, short headways, stringent ride quality requirements, and a distributed offboard propulsion system necessitates high levels of automation for the Maglev control and operation. Very high levels of safety and availability will be required for the Maglev control system. This paper describes the mission scenario, functional requirements, and dependability and performance requirements of the Maglev command, control, and communications system. A distributed hierarchical architecture consisting of vehicle on-board computers, wayside zone computers, a central computer facility, and communication links between these entities was synthesized to meet the functional and dependability requirements on the maglev. Two variations of the basic architecture are described: the Smart Vehicle Architecture (SVA) and the Zone Control Architecture (ZCA). Preliminary dependability modeling results are also presented.

  16. Computer-controlled cryogenic-temperature controller. Final report, September 1982-January 1984

    SciTech Connect

    Perrin, R.E.

    1990-01-10

    In laboratories which do materials characterization it is necessary to have a temperature controller which can be computer controlled, is accurate to within .1-.2K, can control temperature from 15-350K with a drift of no more than .1, and is relatively unaffected by the presence of a magnetic field on the sample container. The subject controller uses two thermometers to meet these requirements. One is a commercially available calibrated silicon diode manufactured expressly for this type of application. The second thermometer is used for control. Once the sample has reached the setpoint according to the calibrated thermometer the control thermometer's value is sampled and used as the new setpoint. Since the control thermometer should be insensitive to a mag field the sample will remain at the desired temperature when the magnetic field is applied. Cryogenic, Computer control, Magnetic field, Cryogenics, Cryogenic storage devices.

  17. Automated quantification of pulmonary emphysema from computed tomography scans: comparison of variation and correlation of common measures in a large cohort

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.

    2010-03-01

    The purpose of this work was to retrospectively investigate the variation of standard indices of pulmonary emphysema from helical computed tomographic (CT) scans as related to inspiration differences over a 1 year interval and determine the strength of the relationship between these measures in a large cohort. 626 patients that had 2 scans taken at an interval of 9 months to 15 months (μ: 381 days, σ: 31 days) were selected for this work. All scans were acquired at a 1.25mm slice thickness using a low dose protocol. For each scan, the emphysema index (EI), fractal dimension (FD), mean lung density (MLD), and 15th percentile of the histogram (HIST) were computed. The absolute and relative changes for each measure were computed and the empirical 95% confidence interval was reported both in non-normalized and normalized scales. Spearman correlation coefficients are computed between the relative change in each measure and relative change in inspiration between each scan-pair, as well as between each pair-wise combination of the four measures. EI varied on a range of -10.5 to 10.5 on a non-normalized scale and -15 to 15 on a normalized scale, with FD and MLD showing slightly larger but comparable spreads, and HIST having a much larger variation. MLD was found to show the strongest correlation to inspiration change (r=0.85, p<0.001), and EI, FD, and HIST to have moderately strong correlation (r = 0.61-0.74, p<0.001). Finally, HIST showed very strong correlation to EI (r = 0.92, p<0.001), while FD showed the least strong relationship to EI (r = 0.82, p<0.001). This work shows that emphysema index and fractal dimension have the least variability overall of the commonly used measures of emphysema and that they offer the most unique quantification of emphysema relative to each other.

  18. Programmable scan/read circuitry for charge coupled device imaging detectors. [spcecraft attitude control and star trackers

    NASA Technical Reports Server (NTRS)

    Salomon, P. M.; Smilowitz, K.

    1984-01-01

    A circuit for scanning and outputting the induced charges in a solid state charge coupled device (CCD) image detector is disclosed in an image detection system for use in a spacecraft attitude control system. The image detection system includes timing control circuitry for selectively controlling the output of the CCD detector so that video outputs are provided only with respect to induced charges corresponding to predetermined sensing element lines of the CCD detector. The timing control circuit and the analog to digital converter are controlled by a programmed microprocessor which defines the video outputs to be converted and further controls the timing control circuit so that no video outputs are provided during the delay associated with analog to digital conversion.

  19. Control aspects of quantum computing using pure and mixed states

    PubMed Central

    Schulte-Herbrüggen, Thomas; Marx, Raimund; Fahmy, Amr; Kauffman, Louis; Lomonaco, Samuel; Khaneja, Navin; Glaser, Steffen J.

    2012-01-01

    Steering quantum dynamics such that the target states solve classically hard problems is paramount to quantum simulation and computation. And beyond, quantum control is also essential to pave the way to quantum technologies. Here, important control techniques are reviewed and presented in a unified frame covering quantum computational gate synthesis and spectroscopic state transfer alike. We emphasize that it does not matter whether the quantum states of interest are pure or not. While pure states underly the design of quantum circuits, ensemble mixtures of quantum states can be exploited in a more recent class of algorithms: it is illustrated by characterizing the Jones polynomial in order to distinguish between different (classes of) knots. Further applications include Josephson elements, cavity grids, ion traps and nitrogen vacancy centres in scenarios of closed as well as open quantum systems. PMID:22946034

  20. COMSAC: Computational Methods for Stability and Control. Part 2

    NASA Technical Reports Server (NTRS)

    Fremaux, C. Michael (Compiler); Hall, Robert M. (Compiler)

    2004-01-01

    The unprecedented advances being made in computational fluid dynamic (CFD) technology have demonstrated the powerful capabilities of codes in applications to civil and military aircraft. Used in conjunction with wind-tunnel and flight investigations, many codes are now routinely used by designers in diverse applications such as aerodynamic performance predictions and propulsion integration. Typically, these codes are most reliable for attached, steady, and predominantly turbulent flows. As a result of increasing reliability and confidence in CFD, wind-tunnel testing for some new configurations has been substantially reduced in key areas, such as wing trade studies for mission performance guarantees. Interest is now growing in the application of computational methods to other critical design challenges. One of the most important disciplinary elements for civil and military aircraft is prediction of stability and control characteristics. CFD offers the potential for significantly increasing the basic understanding, prediction, and control of flow phenomena associated with requirements for satisfactory aircraft handling characteristics.

  1. Latent-failure risk estimates for computer control

    NASA Technical Reports Server (NTRS)

    Dunn, William R.; Folsom, Rolfe A.; Green, Owen R.

    1991-01-01

    It is shown that critical computer controls employing unmonitored safety circuits are unsafe. Analysis supporting this result leads to two additional, important conclusions: (1) annual maintenance checks of safety circuit function do not, as widely believed, eliminate latent failure risk; (2) safety risk remains even if multiple, series-connected protection circuits are employed. Finally, it is shown analytically that latent failure risk is eliminated when continuous monitoring is employed.

  2. Computer model of cardiovascular control system responses to exercise

    NASA Technical Reports Server (NTRS)

    Croston, R. C.; Rummel, J. A.; Kay, F. J.

    1973-01-01

    Approaches of systems analysis and mathematical modeling together with computer simulation techniques are applied to the cardiovascular system in order to simulate dynamic responses of the system to a range of exercise work loads. A block diagram of the circulatory model is presented, taking into account arterial segments, venous segments, arterio-venous circulation branches, and the heart. A cardiovascular control system model is also discussed together with model test results.

  3. Robot Control Through Brain Computer Interface For Patterns Generation

    NASA Astrophysics Data System (ADS)

    Belluomo, P.; Bucolo, M.; Fortuna, L.; Frasca, M.

    2011-09-01

    A Brain Computer Interface (BCI) system processes and translates neuronal signals, that mainly comes from EEG instruments, into commands for controlling electronic devices. This system can allow people with motor disabilities to control external devices through the real-time modulation of their brain waves. In this context an EEG-based BCI system that allows creative luminous artistic representations is here presented. The system that has been designed and realized in our laboratory interfaces the BCI2000 platform performing real-time analysis of EEG signals with a couple of moving luminescent twin robots. Experiments are also presented.

  4. Introduction to Computational Methods for Stability and Control (COMSAC)

    NASA Technical Reports Server (NTRS)

    Hall, Robert M.; Fremaux, C. Michael; Chambers, Joseph R.

    2004-01-01

    This Symposium is intended to bring together the often distinct cultures of the Stability and Control (S&C) community and the Computational Fluid Dynamics (CFD) community. The COMSAC program is itself a new effort by NASA Langley to accelerate the application of high end CFD methodologies to the demanding job of predicting stability and control characteristics of aircraft. This talk is intended to set the stage for needing a program like COMSAC. It is not intended to give details of the program itself. The topics include: 1) S&C Challenges; 2) Aero prediction methodology; 3) CFD applications; 4) NASA COMSAC planning; 5) Objectives of symposium; and 6) Closing remarks.

  5. Computer simulation of multigrid body dynamics and control

    NASA Technical Reports Server (NTRS)

    Swaminadham, M.; Moon, Young I.; Venkayya, V. B.

    1990-01-01

    The objective is to set up and analyze benchmark problems on multibody dynamics and to verify the predictions of two multibody computer simulation codes. TREETOPS and DISCOS have been used to run three example problems - one degree-of-freedom spring mass dashpot system, an inverted pendulum system, and a triple pendulum. To study the dynamics and control interaction, an inverted planar pendulum with an external body force and a torsional control spring was modeled as a hinge connected two-rigid body system. TREETOPS and DISCOS affected the time history simulation of this problem. System state space variables and their time derivatives from two simulation codes were compared.

  6. Computational Study on Temperature Control Systems for Thermoelectric Refrigerators

    NASA Astrophysics Data System (ADS)

    Astrain, D.; Martínez, A.; Gorraiz, J.; Rodríguez, A.; Pérez, G.

    2012-06-01

    Thermoelectric refrigeration has the outstanding advantage of allowing accurate temperature control. However, on the market there are thermoelectric refrigerators which include on/off temperature control systems, because of their simplicity and low cost. The major problem with this system is that, when the thermoelectric modules are switched off, the heat stored in the heat exchanger at the hot end of the modules goes back into the refrigerator, forming a thermal bridge. In this work, we use a computational model, presented and validated in previous papers, to study alternative control systems. A new system is introduced based on idling voltages; that is, once the temperature of the refrigerator reaches the lower limit, the thermoelectric modules are not switched off but supplied with minimum voltage. Computational results prove that this system reduces the electric power consumption of the refrigerator by at least 40% with respect to that obtained with on/off control systems, and the coefficient of performance increases close to the maximum provided by any other control system.

  7. Computation of a controlled store separation from a cavity

    NASA Technical Reports Server (NTRS)

    Atwood, Christopher A.

    1993-01-01

    Coupling of the Reynolds-averaged Navier-Stokes equations, rigid-body dynamics, and a pitch attitude control law is demonstrated in two- and three-dimensions. The application problem was the separation of a canard-controlled store from an open-flow rectangular cavity bay at a freestream Mach number of 1.2. The transient flowfield was computed using a diagonal scheme in an overset mesh framework, with the resultant aerodynamic loads used as the forcing functions in the nonlinear dynamics equations. The proportional and rate gyro sensitivities were computed a priori using pole placement techniques for the linearized dynamical equations. These fixed gain values were used in the controller for the nonlinear simulation. Reasonable comparison between the full and linearized equations for a perturbed two-dimensional missile was found. Also in two-dimensions, a controlled store was found to possess improved separation characteristics over a canard-fixed store. In three-dimensions, trajectory comparisons with wind-tunnel data for the canard-fixed case will be made. In addition, it will be determined if a canard-controlled store is an effective means of improving cavity store separation characteristics.

  8. Use of Soft Computing Technologies For Rocket Engine Control

    NASA Technical Reports Server (NTRS)

    Trevino, Luis C.; Olcmen, Semih; Polites, Michael

    2003-01-01

    The problem to be addressed in this paper is to explore how the use of Soft Computing Technologies (SCT) could be employed to further improve overall engine system reliability and performance. Specifically, this will be presented by enhancing rocket engine control and engine health management (EHM) using SCT coupled with conventional control technologies, and sound software engineering practices used in Marshall s Flight Software Group. The principle goals are to improve software management, software development time and maintenance, processor execution, fault tolerance and mitigation, and nonlinear control in power level transitions. The intent is not to discuss any shortcomings of existing engine control and EHM methodologies, but to provide alternative design choices for control, EHM, implementation, performance, and sustaining engineering. The approaches outlined in this paper will require knowledge in the fields of rocket engine propulsion, software engineering for embedded systems, and soft computing technologies (i.e., neural networks, fuzzy logic, and Bayesian belief networks), much of which is presented in this paper. The first targeted demonstration rocket engine platform is the MC-1 (formerly FASTRAC Engine) which is simulated with hardware and software in the Marshall Avionics & Software Testbed laboratory that

  9. CRionScan: A stand-alone real time controller designed to perform ion beam imaging, dose controlled irradiation and proton beam writing

    NASA Astrophysics Data System (ADS)

    Daudin, L.; Barberet, Ph.; Serani, L.; Moretto, Ph.

    2013-07-01

    High resolution ion microbeams, usually used to perform elemental mapping, low dose targeted irradiation or ion beam lithography needs a very flexible beam control system. For this purpose, we have developed a dedicated system (called “CRionScan”), on the AIFIRA facility (Applications Interdisciplinaires des Faisceaux d'Ions en Région Aquitaine). It consists of a stand-alone real-time scanning and imaging instrument based on a Compact Reconfigurable Input/Output (Compact RIO) device from National Instruments™. It is based on a real-time controller, a Field Programmable Gate Array (FPGA), input/output modules and Ethernet connectivity. We have implemented a fast and deterministic beam scanning system interfaced with our commercial data acquisition system without any hardware development. CRionScan is built under LabVIEW™ and has been used on AIFIRA's nanobeam line since 2009 (Barberet et al., 2009, 2011) [1,2]. A Graphical User Interface (GUI) embedded in the Compact RIO as a web page is used to control the scanning parameters. In addition, a fast electrostatic beam blanking trigger has been included in the FPGA and high speed counters (15 MHz) have been implemented to perform dose controlled irradiation and on-line images on the GUI. Analog to Digital converters are used for the beam current measurement and in the near future for secondary electrons imaging. Other functionalities have been integrated in this controller like LED lighting using Pulse Width Modulation and a “NIM Wilkinson ADC” data acquisition.

  10. Iterative learning control for synchronization of reticle stage and wafer stage in step-and-scan lithographic equipment

    NASA Astrophysics Data System (ADS)

    Li, Lan-lan; Hu, Song; Zhao, Li-xin; Ma, Ping

    2013-08-01

    Lithographic equipments are highly complex machines used to manufacture integrated circuits (ICs). To make larger ICs, a larger lens is required, which, however, is prohibitively expensive. The solution to this problem is to expose a chip not in one flash but in a scanning fashion. For step-and-scan lithographic equipment (wafer scanner), the image quality is decided by many factors, in which synchronization of reticle stage and wafer stage during exposure is a key one. In this paper, the principle of reticle stage and wafer stage was analyzed through investigating the structure of scanners, firstly. While scanning, the reticle stage and wafer stage should scan simultaneously at a high speed and the speed ratio is 1:4. Secondly, an iterative learning controller (ILC) for synchronization of reticle stage and wafer stage is presented. In the controller, a master-slave structure is used, with the wafer stage acting as the master, and the reticle stage as the slave. Since the scanning process of scanner is repetitive, ILC is used to improve tracking performance. A simple design procedure is presented which allows design of the ILC system for the reticle stage and wafer stage independently. Finally, performance of the algorithm is illustrated by simulated on the virtual stages (the reticle stage and wafer stage).The results of simulation experiments and theory analyzing demonstrate that using the proposed controller better synchronization performance can be obtained for the reticle stage and wafer stage in scanner. Theory analysis and experiment shows the method is reasonable and efficient.

  11. Computer-aided diagnosis of pulmonary nodules on CT scans: Segmentation and classification using 3D active contours

    PubMed Central

    Way, Ted W.; Hadjiiski, Lubomir M.; Sahiner, Berkman; Chan, Heang-Ping; Cascade, Philip N.; Kazerooni, Ella A.; Bogot, Naama; Zhou, Chuan

    2009-01-01

    We are developing a computer-aided diagnosis (CAD) system to classify malignant and benign lung nodules found on CT scans. A fully automated system was designed to segment the nodule from its surrounding structured background in a local volume of interest (VOI) and to extract image features for classification. Image segmentation was performed with a three-dimensional (3D) active contour (AC) method. A data set of 96 lung nodules (44 malignant, 52 benign) from 58 patients was used in this study. The 3D AC model is based on two-dimensional AC with the addition of three new energy components to take advantage of 3D information: (1) 3D gradient, which guides the active contour to seek the object surface, (2) 3D curvature, which imposes a smoothness constraint in the z direction, and (3) mask energy, which penalizes contours that grow beyond the pleura or thoracic wall. The search for the best energy weights in the 3D AC model was guided by a simplex optimization method. Morphological and gray-level features were extracted from the segmented nodule. The rubber band straightening transform (RBST) was applied to the shell of voxels surrounding the nodule. Texture features based on run-length statistics were extracted from the RBST image. A linear discriminant analysis classifier with stepwise feature selection was designed using a second simplex optimization to select the most effective features. Leave-one-case-out resampling was used to train and test the CAD system. The system achieved a test area under the receiver operating characteristic curve (Az) of 0.83±0.04. Our preliminary results indicate that use of the 3D AC model and the 3D texture features surrounding the nodule is a promising approach to the segmentation and classification of lung nodules with CAD. The segmentation performance of the 3D AC model trained with our data set was evaluated with 23 nodules available in the Lung Image Database Consortium (LIDC). The lung nodule volumes segmented by the 3D AC

  12. Perceptions of Control and Use of Control Options in Computer-Assisted Video Instruction.

    ERIC Educational Resources Information Center

    Gay, Geri; And Others

    1988-01-01

    Discussion of the effectiveness of learner control in computer assisted instruction focuses on a study of undergraduates at Cornell University using an interactive videodisc lesson on waterfowl identification. Opportunities for students to modify the delivery of the program are described, and the effects of student expectations of control on…

  13. Computer Numerical Control: Instructional Manual. The North Dakota High Technology Mobile Laboratory Project.

    ERIC Educational Resources Information Center

    Sinn, John W.

    This instructional manual contains five learning activity packets for use in a workshop on computer numerical control for computer-aided manufacturing. The lessons cover the following topics: introduction to computer-aided manufacturing, understanding the lathe, using the computer, computer numerically controlled part programming, and executing a…

  14. INVESTIGATION OF PRIMARY FINE PARTICULATE MATTER FROM COAL COMBUSTION BY COMPUTER-CONTROLLED SCANNING ELECTRON MICROSCOPY

    EPA Science Inventory

    The particle size distributions, morphologies, and chemical composition distributions of 14 coal fly ash (CFA) samples produced by the combustion of four western U.S. coals (two subbituminous, one lignite, and one bituminous) and three eastern U.S. coals (all bituminous) have bee...

  15. JPL control/structure interaction test bed real-time control computer architecture

    NASA Technical Reports Server (NTRS)

    Briggs, Hugh C.

    1989-01-01

    The Control/Structure Interaction Program is a technology development program for spacecraft that exhibit interactions between the control system and structural dynamics. The program objectives include development and verification of new design concepts - such as active structure - and new tools - such as combined structure and control optimization algorithm - and their verification in ground and possibly flight test. A focus mission spacecraft was designed based upon a space interferometer and is the basis for design of the ground test article. The ground test bed objectives include verification of the spacecraft design concepts, the active structure elements and certain design tools such as the new combined structures and controls optimization tool. In anticipation of CSI technology flight experiments, the test bed control electronics must emulate the computation capacity and control architectures of space qualifiable systems as well as the command and control networks that will be used to connect investigators with the flight experiment hardware. The Test Bed facility electronics were functionally partitioned into three units: a laboratory data acquisition system for structural parameter identification and performance verification; an experiment supervisory computer to oversee the experiment, monitor the environmental parameters and perform data logging; and a multilevel real-time control computing system. The design of the Test Bed electronics is presented along with hardware and software component descriptions. The system should break new ground in experimental control electronics and is of interest to anyone working in the verification of control concepts for large structures.

  16. A computer controlled 100 kV pulse generator

    SciTech Connect

    Kupferman, S.L.; Booker, S.R.; Meissner, H.J.

    1989-01-01

    A high voltage pulse generator used primarily for calibrating precision high voltage dividers has been redesigned and rebuilt for state of the art operation. It now has the capability to run a divider calibration, compare the results with historical data for the divider, and then print a calibration certificate, all under computer control. Thirteen component instruments are controlled via three IEEE 488 buses. A voice synthesizer is used to inform the operator of the progress of the calibration. Measurement precision is in the 0.1 % range. A heat exchanger is used to control the temperature of the oil bath to allow calibration of dividers between 13/degree/C (55/degree/F) and 21/degree/C (70/degree/F). Positive or negative pulse polarity may be selected and pulse magnitude is settable from less than 10 kV to greater than 300 kV. 1 ref., 8 figs., 1 tab.

  17. Full phase and amplitude control in computer-generated holography.

    PubMed

    Fratz, Markus; Fischer, Peer; Giel, Dominik M

    2009-12-01

    We report what we believe to be the first realization of a computer-generated complex-valued hologram recorded in a single film of photoactive polymer. Complex-valued holograms give rise to a diffracted optical field with control over its amplitude and phase. The holograms are generated by a one-step direct laser writing process in which a spatial light modulator (SLM) is imaged onto a polymer film. Temporal modulation of the SLM during exposure controls both the strength of the induced birefringence and the orientation of the fast axis. We demonstrate that complex holograms can be used to impart arbitrary amplitude and phase profiles onto a beam and thereby open new possibilities in the control of optical beams. PMID:19953153

  18. Integrated command, control, communications and computation system functional architecture

    NASA Technical Reports Server (NTRS)

    Cooley, C. G.; Gilbert, L. E.

    1981-01-01

    The functional architecture for an integrated command, control, communications, and computation system applicable to the command and control portion of the NASA End-to-End Data. System is described including the downlink data processing and analysis functions required to support the uplink processes. The functional architecture is composed of four elements: (1) the functional hierarchy which provides the decomposition and allocation of the command and control functions to the system elements; (2) the key system features which summarize the major system capabilities; (3) the operational activity threads which illustrate the interrelationahip between the system elements; and (4) the interfaces which illustrate those elements that originate or generate data and those elements that use the data. The interfaces also provide a description of the data and the data utilization and access techniques.

  19. Scanning ARM Cloud Radars. Part II: Data Quality Control and Processing

    SciTech Connect

    Kollias, Pavlos; Jo, Ieng; Borque, Paloma; Tatarevic, Aleksandra; Lamer, Katia; Bharadwaj, Nitin; Widener, Kevin B.; Johnson, Karen L.; Clothiaux, Eugene E.

    2014-03-01

    The Scanning ARM Cloud Radars (SACR’s) are the primary instruments for documenting the four-dimensional structure and evolution of clouds within a 20-30 km radius from the ARM fixed and mobile sites. Here, the post-processing of the calibrated SACR measurements is discussed. First, a feature mask algorithm that objectively determines the presence of significant radar returns is described. The feature mask algorithm is based on the statistical properties of radar receiver noise. It accounts for atmospheric emission and is applicable even for SACR profiles with few or no signal-free range gates. Using the nearest-in-time atmospheric sounding, the SACR radar reflectivities are corrected for gaseous attenuation (water vapor and oxygen) using a line-by-line absorption model. Despite having a high pulse repetition frequency, the SACR has a narrow Nyquist velocity limit and thus Doppler velocity folding is commonly observed. An unfolding algorithm that makes use of a first guess for the true Doppler velocity using horizontal wind measurements from the nearest sounding is described. The retrieval of the horizontal wind profile from the HS-RHI SACR scan observations and/or nearest sounding is described. The retrieved horizontal wind profile can be used to adaptively configure SACR scan strategies that depend on wind direction. Several remaining challenges are discussed, including the removal of insect and second-trip echoes. The described algorithms significantly enhance SACR data quality and constitute an important step towards the utilization of SACR measurements for cloud research.

  20. Dental image replacement on cone beam computed tomography with three-dimensional optical scanning of a dental cast, occlusal bite, or bite tray impression.

    PubMed

    Kang, S-H; Lee, J-W; Lim, S-H; Kim, Y-H; Kim, M-K

    2014-10-01

    The goal of the present study was to compare the accuracy of dental image replacement on a cone beam computed tomography (CBCT) image using digital image data from three-dimensional (3D) optical scanning of a dental cast, occlusal bite, and bite tray impression. A Bracket Typodont dental model was used. CBCT of the dental model was performed and the data were converted to stereolithography (STL) format. Three experimental materials, a dental cast, occlusal bite, and bite tray impression, were optically scanned in 3D. STL files converted from the CBCT of the Typodont model and the 3D optical-scanned STL files of the study materials were image-registered. The error range of each methodology was measured and compared with a 3D optical scan of the Typodont. For the three materials, the smallest error observed was 0.099±0.114mm (mean error±standard deviation) for registering the 3D optical scan image of the dental cast onto the CBCT dental image. Although producing a dental cast can be laborious, the study results indicate that it is the preferred method. In addition, an occlusal bite is recommended when bite impression materials are used. PMID:25015906

  1. Quantifying Appropriate PTV Setup Margins: Analysis of Patient Setup Fidelity and Intrafraction Motion Using Post-Treatment Megavoltage Computed Tomography Scans

    SciTech Connect

    Drabik, Donata M.; MacKenzie, Marc A.; Fallone, Gino B. . E-mail: ginofall@cancerboard.ab.ca

    2007-07-15

    Purpose: To present a technique that can be implemented in-house to evaluate the efficacy of immobilization and image-guided setup of patients with different treatment sites on helical tomotherapy. This technique uses an analysis of alignment shifts between kilovoltage computed tomography and post-treatment megavoltage computed tomography images. The determination of the shifts calculated by the helical tomotherapy software for a given site can then be used to define appropriate planning target volume internal margins. Methods and Materials: Twelve patients underwent post-treatment megavoltage computed tomography scans on a helical tomotherapy machine to assess patient setup fidelity and net intrafraction motion. Shifts were studied for the prostate, head and neck, and glioblastoma multiforme. Analysis of these data was performed using automatic and manual registration of the kilovoltage computed tomography and post-megavoltage computed tomography images. Results: The shifts were largest for the prostate, followed by the head and neck, with glioblastoma multiforme having the smallest shifts in general. It appears that it might be more appropriate to use asymmetric planning target volume margins. Each margin value reported is equal to two standard deviations of the average shift in the given direction. Conclusion: This method could be applied using individual patient post-image scanning and combined with adaptive planning to reduce or increase the margins as appropriate.

  2. [Computer-assisted control of a public health inventory].

    PubMed

    Beckmann, W; Dörr, M; Höhmann, J

    1989-04-01

    To cope with its tasks more efficiently, the Public Health Office of the "Märkische Kreis" in 1985 installed an information system on the basis of electronic data processing, the so-called "hygiene inventory". Initially, the introduction of this system into the local Public Health Office is described. The structure and organization of the programme and its performance are then discussed and exemplified by the control of drinking water supply plants. The disadvantages of computer use are by no means overlooked. The latter include the necessity to initially put in a considerable number of data and to constantly store new results, initial acceptance problems and the poor autonomy of the system. The most important advantages of computer-aided processing are optimum evaluation possibilities, centralised scheduling, automated production of letters, efficient drafting of the annual health report and the possibility of exchanging data media. PMID:2525684

  3. Image quality evaluation and control of computer-generated holograms

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Hiroshi; Yamaguchi, Takeshi; Uetake, Hiroki

    2016-03-01

    Image quality of the computer-generated holograms are usually evaluated subjectively. For example, the re- constructed image from the hologram is compared with other holograms, or evaluated by the double-stimulus impairment scale method to compare with the original image. This paper proposes an objective image quality evaluation of a computer-generated hologram by evaluating both diffraction efficiency and peak signal-to-noise ratio. Theory and numerical experimental results are shown on Fourier transform transmission hologram of both amplitude and phase modulation. Results without the optimized random phase show that the amplitude transmission hologram gives better peak signal-to noise ratio, but the phase transmission hologram provides about 10 times higher diffraction efficiency to the amplitude type. As an optimized phase hologram, Kinoform is evaluated. In addition, we investigate to control image quality by non-linear operation.

  4. Computational investigation of slot blowing for fuselage forebody flow control

    NASA Technical Reports Server (NTRS)

    Murman, Scott M.; Rizk, Yehia M.; Schiff, Lewis B.; Cummings, Russell M.

    1992-01-01

    This paper presents a computational investigation of a tangential slot blowing concept for generating lateral control forces on an aircraft fuselage forebody. The effects of varying both the jet width and jet exit velocity for a fixed location slot are analyzed. This work is aimed at aiding researchers in designing future experimental and computational models of tangential slot blowing. The primary influence on the resulting side force of the forebody is seen to be the jet mass flow rate. This influence is sensitive to different combinations of slot widths and jet velocities over the range of variables considered. Both an actuator plane and an overset grid technique are used to model the tangential slot. The overset method successfully resolves the details of the actual slot geometry, extending the generality of the numerical method. The actuator plane concept predicts side forces similar to those produced by resolving the actual slot geometry.

  5. Diagnostic Phase of Calcium Scoring Scan Applied as the Center of Acquisition Window of Coronary Computed Tomography Angiography Improves Image Quality in Minimal Acquisition Window Scan (Target CTA Mode) Using the Second Generation 320-Row CT

    PubMed Central

    Maeda, Eriko; Kanno, Shigeaki; Ino, Kenji; Tomizawa, Nobuo; Akahane, Masaaki; Torigoe, Rumiko; Ohtomo, Kuni

    2016-01-01

    Objective. To compare the image quality of coronary computed tomography angiography (CCTA) acquired under two conditions: 75% fixed as the acquisition window center (Group 75%) and the diagnostic phase for calcium scoring scan as the center (CS; Group CS). Methods. 320-row cardiac CT with a minimal acquisition window (scanned using “Target CTA” mode) was performed on 81 patients. In Group 75% (n = 40), CS was obtained and reconstructed at 75% and the center of the CCTA acquisition window was set at 75%. In Group CS (n = 41), CS was obtained at 75% and the diagnostic phase showing minimal artifacts was applied as the center of the CCTA acquisition window. Image quality was evaluated using a four-point scale (4-excellent) and the mean scores were compared between groups. Results. The CCTA scan diagnostic phase occurred significantly earlier in CS (75.7 ± 3.2% vs. 73.6 ± 4.5% for Groups 75% and CS, resp., p = 0.013). The mean Group CS image quality score (3.58 ± 0.63) was also higher than that for Group 75% (3.19 ± 0.66, p < 0.0001). Conclusions. The image quality of CCTA in Target CTA mode was significantly better when the center of acquisition window is adjusted using CS. PMID:26977449

  6. Optical scanning cryptography

    NASA Astrophysics Data System (ADS)

    Poon, Ting-Chung

    2004-01-01

    We introduce a technique called optical scanning cryptography (OSC). The technique can perform encryption on-the-fly using laser beams and can be implemented using an optical heterodyne scanning. We shall first describe the optical heterodyne scanning system and then provide some computer simulations to clarify and confirm the idea of encryption and decryption.

  7. Upgrading NASA/DOSE laser ranging system control computers

    NASA Technical Reports Server (NTRS)

    Ricklefs, Randall L.; Cheek, Jack; Seery, Paul J.; Emenheiser, Kenneth S.; Hanrahan, William P., III; Mcgarry, Jan F.

    1993-01-01

    Laser ranging systems now managed by the NASA Dynamics of the Solid Earth (DOSE) and operated by the Bendix Field Engineering Corporation, the University of Hawaii, and the University of Texas have produced a wealth on interdisciplinary scientific data over the last three decades. Despite upgrades to the most of the ranging station subsystems, the control computers remain a mix of 1970's vintage minicomputers. These encompass a wide range of vendors, operating systems, and languages, making hardware and software support increasingly difficult. Current technology allows replacement of controller computers at a relatively low cost while maintaining excellent processing power and a friendly operating environment. The new controller systems are now being designed using IBM-PC-compatible 80486-based microcomputers, a real-time Unix operating system (LynxOS), and X-windows/Motif IB, and serial interfaces have been chosen. This design supports minimizing short and long term costs by relying on proven standards for both hardware and software components. Currently, the project is in the design and prototyping stage with the first systems targeted for production in mid-1993.

  8. Computational motor control as a window to understanding schizophrenia.

    PubMed

    Izawa, Jun; Asai, Tomohisa; Imamizu, Hiroshi

    2016-03-01

    In addition to mental disorders such as attention, emotion, delusions, hallucinations, and difficulties in social skills, the patients with schizophrenia exhibits significant abnormality in sensorimotor perception and control. To seek a neurobiological cause of the heterogeneous symptoms in schizophrenia, we focused on the impaired inference mechanism of the self-agency of the schizophrenia's brain where the sensory outcome generated by the self-initiated action was misattributed to the other agent's action. By developing a novel computational model of agency experience using a Bayesian decision making framework, we united the computational mechanisms of agency and motor control via internal model: a model for one to predict the sensory consequence of action. Our theory based on optimal feedback control with Kalman filtering successfully predicted a variety of schizophrenia's motor abnormalities assuming a deformed internal model. To discuss the plausibility of these model predictions, we reviewed literature that might support these predictions. We further proposed some experiments that potentially examine the proposed model of schizophrenia. Our approach in investigating a problem of mind by projecting it on the coordinates system of the embodiment effectively shed light on a central neuropathology of this disease that had been latent behind the observed behaviors. PMID:26592778

  9. Quantitative assessment of computed radiography quality control parameters.

    PubMed

    Rampado, O; Isoardi, P; Ropolo, R

    2006-03-21

    Quality controls for testing the performance of computed radiography (CR) systems have been recommended by manufacturers and medical physicists' organizations. The purpose of this work was to develop a set of image processing tools for quantitative assessment of computed radiography quality control parameters. Automatic image analysis consisted in detecting phantom details, defining regions of interest and acquiring measurements. The tested performance characteristics included dark noise, uniformity, exposure calibration, linearity, low-contrast and spatial resolution, spatial accuracy, laser beam function and erasure thoroughness. CR devices from two major manufacturers were evaluated. We investigated several approaches to quantify the detector response uniformity. We developed methods to characterize the spatial accuracy and resolution properties across the entire image area, based on the Fourier analysis of the image of a fine wire mesh. The implemented methods were sensitive to local blurring and allowed us to detect a local distortion of 4% or greater in any part of an imaging plate. The obtained results showed that the developed image processing tools allow us to implement a quality control program for CR with short processing time and with absence of subjectivity in the evaluation of the parameters. PMID:16510964

  10. Computer simulation of residual stresses/distortion and structural change in the course of scanning induction hardening

    SciTech Connect

    Ikuta, F.; Arimoto, K.; Inoue, T.

    1996-12-31

    Simulated results of structural change, residual stresses and distortion are presented for carbon steel cylinder in the scanning-type induction hardening process by a CAE system {open_quotes}HEARTS (HEAt tReaTment Simulation system){close_quotes}. The system HEARTS has been developed to simulate heat treatment processes based on {open_quotes}metallo-thermo-mechanics{close_quotes} available for describing the coupling effect between metallurgical change due to phase transformation, temperature and inelastic stress/strain. A steel cylinder is treated as an axisymmetric model with scanning internal heat generation and convection boundary. The results under different scanning velocity and magnitude of the heat source from induction coil are compared with experimental data of distortions, volume fraction of metallic phases as well as residual stresses.

  11. Safety issues of manipulator systems under computer control

    NASA Technical Reports Server (NTRS)

    Andary, James F.; Carter, Ruth C.; Halterman, Karen; Spidaliere, Peter D.; Tasevoli, Michael; Rad, Adrian L.

    1992-01-01

    An overview of the development test flight (DTF-1) mission is presented, and the system design, safety requirements, and safety features are described. The lessons that were learned during the design and early development stages are also presented. The DTF-1 mission objectives are to evaluate: the overall man-machine performance in zero G, Flight Telerobotic Service manipulator design, and workstation design, including handcontrollers and displays. The payload bay and aft flight deck elements, and computer control of the DTF-1 are described. Recommendations for developing and implementing a safety system are presented, and some design alternatives for the next space-qualified telerobotic system are suggested.

  12. Characterization of a Recoverable Flight Control Computer System

    NASA Technical Reports Server (NTRS)

    Malekpour, Mahyar; Torres, Wilfredo

    1999-01-01

    The design and development of a Closed-Loop System to study and evaluate the performance of the Honeywell Recoverable Computer System (RCS) in electromagnetic environments (EME) is presented. The development of a Windows-based software package to handle the time-critical communication of data and commands between the RCS and flight simulation code in real-time while meeting the stringent hard deadlines is also submitted. The performance results of the RCS and characteristics of its upset recovery scheme while exercising flight control laws under ideal conditions as well as in the presence of electromagnetic fields are also discussed.

  13. Structural mode significance using INCA. [Interactive Controls Analysis computer program

    NASA Technical Reports Server (NTRS)

    Bauer, Frank H.; Downing, John P.; Thorpe, Christopher J.

    1990-01-01

    Structural finite element models are often too large to be used in the design and analysis of control systems. Model reduction techniques must be applied to reduce the structural model to manageable size. In the past, engineers either performed the model order reduction by hand or used distinct computer programs to retrieve the data, to perform the significance analysis and to reduce the order of the model. To expedite this process, the latest version of INCA has been expanded to include an interactive graphical structural mode significance and model order reduction capability.

  14. Computer model of one-dimensional equilibrium controlled sorption processes

    USGS Publications Warehouse

    Grove, D.B.; Stollenwerk, K.G.

    1984-01-01

    A numerical solution to the one-dimensional solute-transport equation with equilibrium-controlled sorption and a first-order irreversible-rate reaction is presented. The computer code is written in FORTRAN language, with a variety of options for input and output for user ease. Sorption reactions include Langmuir, Freundlich, and ion-exchange, with or without equal valance. General equations describing transport and reaction processes are solved by finite-difference methods, with nonlinearities accounted for by iteration. Complete documentation of the code, with examples, is included. (USGS)

  15. Scanning ARM Cloud Radars Part II. Data Quality Control and Processing

    SciTech Connect

    Kollias, Pavlos; Jo, Ieng; Borque, Paloma; Tatarevic, Aleksandra; Lamer, Katia; Bharadwaj, Nitin; Widener, Kevin B.; Johnson, Karen; Clothiaux, Eugene E.

    2013-10-04

    The Scanning ARM Cloud Radars (SACR’s) are the primary instruments for documenting the four-dimensional structure and evolution of clouds within a 20-30 km radius from the ARM fixed and mobile sites. Here, the post-processing of the calibrated SACR measurements is discussed. First, a feature mask algorithm that objectively determines the presence of significant radar returns is described. The feature mask algorithm is based on the statistical properties of radar receiver noise. It accounts for atmospheric emission and is applicable even for SACR profiles with few or no signal-free range gates. Using the nearest-in-time atmospheric sounding, the SACR radar reflectivities are corrected for gaseous attenuation (water vapor and oxygen) using a line-by-line absorption model. Despite having a high pulse repetition frequency, the SACR has a narrow Nyquist velocity limit and thus Doppler velocity folding is commonly observed. An unfolding algorithm that makes use of a first guess for the true Doppler velocity using horizontal wind measurements from the nearest sounding is described. The retrieval of the horizontal wind profile from the Hemispherical Sky – Range Height Indicator SACR scan observations and/or nearest sounding is described. The retrieved horizontal wind profile can be used to adaptively configure SACR scan strategies that depend on wind direction. Several remaining challenges are discussed, including the removal of insect and second-trip echoes. The described algorithms significantly enhance SACR data quality and constitute an important step towards the utilization of SACR measurements for cloud research.

  16. Controlling the False-Positive Rate in Multilocus Genome Scans for Selection

    PubMed Central

    Thornton, Kevin R.; Jensen, Jeffrey D.

    2007-01-01

    Rapid typing of genetic variation at many regions of the genome is an efficient way to survey variability in natural populations in an effort to identify segments of the genome that have experienced recent natural selection. Following such a genome scan, individual regions may be chosen for further sequencing and a more detailed analysis of patterns of variability, often to perform a parametric test for selection and to estimate the strength of a recent selective sweep. We show here that not accounting for the ascertainment of loci in such analyses leads to false inference of natural selection when the true model is selective neutrality, because the procedure of choosing unusual loci (in comparison to the rest of the genome-scan data) selects regions of the genome with genealogies similar to those expected under models of recent directional selection. We describe a simple and efficient correction for this ascertainment bias, which restores the false-positive rate to near-nominal levels. For the parameters considered here, we find that obtaining a test with the expected distribution of P-values depends on accurately accounting both for ascertainment of regions and for demography. Finally, we use simulations to explore the utility of relying on outlier loci to detect recent selective sweeps. We find that measures of diversity and of population differentiation are more effective than summaries of the site-frequency spectrum and that sequencing larger regions (2.5 kbp) in genome-scan studies leads to more power to detect recent selective sweeps. PMID:17110489

  17. Effective Control of Computationally Simulated Wing Rock in Subsonic Flow

    NASA Technical Reports Server (NTRS)

    Kandil, Osama A.; Menzies, Margaret A.

    1997-01-01

    The unsteady compressible, full Navier-Stokes (NS) equations and the Euler equations of rigid-body dynamics are sequentially solved to simulate the delta wing rock phenomenon. The NS equations are solved time accurately, using the implicit, upwind, Roe flux-difference splitting, finite-volume scheme. The rigid-body dynamics equations are solved using a four-stage Runge-Kutta scheme. Once the wing reaches the limit-cycle response, an active control model using a mass injection system is applied from the wing surface to suppress the limit-cycle oscillation. The active control model is based on state feedback and the control law is established using pole placement techniques. The control law is based on the feedback of two states: the roll-angle and roll velocity. The primary model of the computational applications consists of a 80 deg swept, sharp edged, delta wing at 30 deg angle of attack in a freestream of Mach number 0.1 and Reynolds number of 0.4 x 10(exp 6). With a limit-cycle roll amplitude of 41.1 deg, the control model is applied, and the results show that within one and one half cycles of oscillation, the wing roll amplitude and velocity are brought to zero.

  18. Simulation of human gait using computed torque control.

    PubMed

    Unver, N F; Tümer, S T; Ozgören, M K

    2000-01-01

    This paper presents a method for the mathematical modeling of both the single and double support phases of the human gait. The governing equations are obtained by considering the linkage model to be in a floating state and the foot-ground interaction is imposed in the form of geometric constraints. Two stages for the single support phase and one stage for the double support phase are considered, each described by a different foot-ground constraint. Feedback controller functioning according to the computed torque control method is used to achieve the normal gait described by the hip and ankle trajectories. Weighted least square optimization is used to solve the redundancy of control torques during the double support phase. The geometric simulation indicates that the imposed trajectories can be realized by the proposed model with some deviations in joint motions. The control strategy is tested by artificially perturbing the trajectories. The corrective actions are able to resume the desired pattern within half cycle, but with control torque magnitudes considerably away from reasonable limits. This is attributed to the insufficiency of the planar kinematic model and the assumption that the joint torques are unbounded. PMID:10942991

  19. (Man-machine interface of computer controlled reactors)

    SciTech Connect

    Knee, H.E.

    1989-11-10

    The traveler and Mr. J.D. White, also of ORNL, met with management and research personnel at the Halden Reactor Project (HRP) in Halden, Norway to assess the potential for future collaborative research between ORNL and the HRP in the areas of advanced controls and man-machine interface. The travelers were provided with two-and-a-half days of briefings and demonstrations that addressed a number of computer-oriented support systems (COSSs) and an integrated surveillance and control system (ISACS). The purpose of the ISACs is to integrate the various COSSs into a super'' support environment for the human operator of a nuclear power plant. The HRP has not only developed a number of COSSs over the past decade, it has also built an experimental environment in which to evaluate the emerging support systems, and to examine the impact on human performance. Most of their research has focused on nuclear-oriented informational displays for the operator, with little to no emphasis on control. The Halden experimental environment and expertise in displays, coupled with ORNL's recognized expertise in the area of advanced controls, could provide strong control system/room design support for DOE's Advanced Reactor Designs, especially the Advanced Liquid Metal Concept.

  20. Region based Brain Computer Interface for a home control application.

    PubMed

    Akman Aydin, Eda; Bay, Omer Faruk; Guler, Inan

    2015-08-01

    Environment control is one of the important challenges for disabled people who suffer from neuromuscular diseases. Brain Computer Interface (BCI) provides a communication channel between the human brain and the environment without requiring any muscular activation. The most important expectation for a home control application is high accuracy and reliable control. Region-based paradigm is a stimulus paradigm based on oddball principle and requires selection of a target at two levels. This paper presents an application of region based paradigm for a smart home control application for people with neuromuscular diseases. In this study, a region based stimulus interface containing 49 commands was designed. Five non-disabled subjects were attended to the experiments. Offline analysis results of the experiments yielded 95% accuracy for five flashes. This result showed that region based paradigm can be used to select commands of a smart home control application with high accuracy in the low number of repetitions successfully. Furthermore, a statistically significant difference was not observed between the level accuracies. PMID:26736451

  1. 3D light scanning macrography.

    PubMed

    Huber, D; Keller, M; Robert, D

    2001-08-01

    The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences. PMID:11489078

  2. Growth Control and Disease Mechanisms in Computational Embryogeny

    NASA Technical Reports Server (NTRS)

    Shapiro, Andrew A.; Yogev, Or; Antonsson, Erik K.

    2008-01-01

    This paper presents novel approach to applying growth control and diseases mechanisms in computational embryogeny. Our method, which mimics fundamental processes from biology, enables individuals to reach maturity in a controlled process through a stochastic environment. Three different mechanisms were implemented; disease mechanisms, gene suppression, and thermodynamic balancing. This approach was integrated as part of a structural evolutionary model. The model evolved continuum 3-D structures which support an external load. By using these mechanisms we were able to evolve individuals that reached a fixed size limit through the growth process. The growth process was an integral part of the complete development process. The size of the individuals was determined purely by the evolutionary process where different individuals matured to different sizes. Individuals which evolved with these characteristics have been found to be very robust for supporting a wide range of external loads.

  3. Computer-controlled preparation of thin tungsten layers

    NASA Astrophysics Data System (ADS)

    Folger, Helmut; Hartmann, Willi; Klemm, Josef; Lommel, Bettina; Thalheimer, Werner

    1997-02-01

    Tungsten layers of 1-6 mg/cm 2 with diameters of 10 mm are needed as heavy-ion targets and as flat or domed windows for in-beam ion sources. They are prepared by a high-vacuum evaporation-deposition process carried out in a computer-controlled apparatus. The tungsten, placed in the water-cooled crucible of an electron-beam gun, is gradually heated and evaporates at about its melting point ( Tm = 3643 K). The tungsten is deposited onto 9 mg/cm 2 copper backings which are preheated by the thermal radiation from the evaporant. The deposition rate is controlled by a quartz crystal monitor. After the high-vacuum deposition process, the copper backings are removed by selective etching and the self-supported tungsten foils are characterized by their areal mass. The features of the commercially available evaporation unit used are discussed by way of this deposition process.

  4. Computational Analysis of the Hypothalamic Control of Food Intake

    PubMed Central

    Tabe-Bordbar, Shayan; Anastasio, Thomas J.

    2016-01-01

    Food-intake control is mediated by a heterogeneous network of different neural subtypes, distributed over various hypothalamic nuclei and other brain structures, in which each subtype can release more than one neurotransmitter or neurohormone. The complexity of the interactions of these subtypes poses a challenge to understanding their specific contributions to food-intake control, and apparent consistencies in the dataset can be contradicted by new findings. For example, the growing consensus that arcuate nucleus neurons expressing Agouti-related peptide (AgRP neurons) promote feeding, while those expressing pro-opiomelanocortin (POMC neurons) suppress feeding, is contradicted by findings that low AgRP neuron activity and high POMC neuron activity can be associated with high levels of food intake. Similarly, the growing consensus that GABAergic neurons in the lateral hypothalamus suppress feeding is contradicted by findings suggesting the opposite. Yet the complexity of the food-intake control network admits many different network behaviors. It is possible that anomalous associations between the responses of certain neural subtypes and feeding are actually consistent with known interactions, but their effect on feeding depends on the responses of the other neural subtypes in the network. We explored this possibility through computational analysis. We made a computer model of the interactions between the hypothalamic and other neural subtypes known to be involved in food-intake control, and optimized its parameters so that model behavior matched observed behavior over an extensive test battery. We then used specialized computational techniques to search the entire model state space, where each state represents a different configuration of the responses of the units (model neural subtypes) in the network. We found that the anomalous associations between the responses of certain hypothalamic neural subtypes and feeding are actually consistent with the known structure

  5. Applications of Computational Methods for Dynamic Stability and Control Derivatives

    NASA Technical Reports Server (NTRS)

    Green, Lawrence L.; Spence, Angela M.

    2004-01-01

    Initial steps in the application o f a low-order panel method computational fluid dynamic (CFD) code to the calculation of aircraft dynamic stability and control (S&C) derivatives are documented. Several capabilities, unique to CFD but not unique to this particular demonstration, are identified and demonstrated in this paper. These unique capabilities complement conventional S&C techniques and they include the ability to: 1) perform maneuvers without the flow-kinematic restrictions and support interference commonly associated with experimental S&C facilities, 2) easily simulate advanced S&C testing techniques, 3) compute exact S&C derivatives with uncertainty propagation bounds, and 4) alter the flow physics associated with a particular testing technique from those observed in a wind or water tunnel test in order to isolate effects. Also presented are discussions about some computational issues associated with the simulation of S&C tests and selected results from numerous surface grid resolution studies performed during the course of the study.

  6. A comparison study of 11C-methionine and 18F-fluorodeoxyglucose positron emission tomography-computed tomography scans in evaluation of patients with recurrent brain tumors

    PubMed Central

    Sharma, Rajnish; D’Souza, Maria; Jaimini, Abhinav; Hazari, Puja Panwar; Saw, Sanjeev; Pandey, Santosh; Singh, Dinesh; Solanki, Yachna; Kumar, Nitin; Mishra, Anil K.; Mondal, Anupam

    2016-01-01

    Introduction: 11C-methonine ([11C]-MET) positron emission tomography-computed tomography (PET-CT) is a well-established technique for evaluation of tumor for diagnosis and treatment planning in neurooncology. [11C]-MET reflects amino acid transport and has been shown to be more sensitive than magnetic resonance imaging (MRI) in stereotactic biopsy planning. This study compared fluorodeoxyglucose (FDG) PET-CT and MET PET-CT in the detection of various brain tumors. Materials and Methods: Sixty-four subjects of brain tumor treated by surgery, chemotherapy, and/or radiotherapy were subjected to [18F]-FDG, [11C]-MET, and MRI scan. The lesion was analyzed semiquantitatively using tumor to normal contralateral ratio. The diagnosis was confirmed by surgery, stereotactic biopsy, clinical follow-up, MRI, or CT scans. Results: Tumor recurrence was found in 5 out of 22 patients on [F-18] FDG scan while [11C]-MET was able to detect recurrence in 18 out of 22 patients in low-grade gliomas. Two of these patients were false positive for the presence of recurrence of tumor and later found to be harboring necrosis. Among oligodendroglioma, medulloblastoma and high-grade glioma out of 42 patients 39 were found to be concordant MET and FDG scans. On semiquantitative analysis, mean T/NT ratio was found to be 2.96 ± 0.94 for lesions positive for recurrence of tumors and 1.18 ± 0.74 for lesions negative for recurrence of tumor on [11C]-MET scan. While the ratio for FDG scan on semiquantitative analysis was found to be 2.05 ± 1.04 for lesions positive for recurrence of tumors and 0.52 ± 0.15 for lesions negative for recurrence of tumors. Conclusion: The study highlight that [11C]-MET is superior to [18F]-FDG PET scans to detect recurrence in low-grade glioma. A cut-off value of target to nontarget value of 1.47 is a useful parameter to distinguish benign from malignant lesion on an [11C]-MET Scan. Both [18F]-FDG and [11C]-MET scans were found to be useful in high-grade astrocytoma

  7. Hydro- abrasive jet machining modeling for computer control and optimization

    NASA Astrophysics Data System (ADS)

    Groppetti, R.; Jovane, F.

    1993-06-01

    Use of hydro-abrasive jet machining (HAJM) for machining a wide variety of materials—metals, poly-mers, ceramics, fiber-reinforced composites, metal-matrix composites, and bonded or hybridized mate-rials—primarily for two- and three-dimensional cutting and also for drilling, turning, milling, and deburring, has been reported. However, the potential of this innovative process has not been explored fully. This article discusses process control, integration, and optimization of HAJM to establish a plat-form for the implementation of real-time adaptive control constraint (ACC), adaptive control optimiza-tion (ACO), and CAD/CAM integration. It presents the approach followed and the main results obtained during the development, implementation, automation, and integration of a HAJM cell and its computer-ized controller. After a critical analysis of the process variables and models reported in the literature to identify process variables and to define a process model suitable for HAJM real-time control and optimi-zation, to correlate process variables and parameters with machining results, and to avoid expensive and time-consuming experiments for determination of the optimal machining conditions, a process predic-tion and optimization model was identified and implemented. Then, the configuration of the HAJM cell, architecture, and multiprogramming operation of the controller in terms of monitoring, control, process result prediction, and process condition optimization were analyzed. This prediction and optimization model for selection of optimal machining conditions using multi-objective programming was analyzed. Based on the definition of an economy function and a productivity function, with suitable constraints relevant to required machining quality, required kerfing depth, and available resources, the model was applied to test cases based on experimental results.

  8. Flexible structure control experiments using a real-time workstation for computer-aided control engineering

    NASA Technical Reports Server (NTRS)

    Stieber, Michael E.

    1989-01-01

    A Real-Time Workstation for Computer-Aided Control Engineering has been developed jointly by the Communications Research Centre (CRC) and Ruhr-Universitaet Bochum (RUB), West Germany. The system is presently used for the development and experimental verification of control techniques for large space systems with significant structural flexibility. The Real-Time Workstation essentially is an implementation of RUB's extensive Computer-Aided Control Engineering package KEDDC on an INTEL micro-computer running under the RMS real-time operating system. The portable system supports system identification, analysis, control design and simulation, as well as the immediate implementation and test of control systems. The Real-Time Workstation is currently being used by CRC to study control/structure interaction on a ground-based structure called DAISY, whose design was inspired by a reflector antenna. DAISY emulates the dynamics of a large flexible spacecraft with the following characteristics: rigid body modes, many clustered vibration modes with low frequencies and extremely low damping. The Real-Time Workstation was found to be a very powerful tool for experimental studies, supporting control design and simulation, and conducting and evaluating tests withn one integrated environment.

  9. A Virtualized Computing Platform For Fusion Control Systems

    SciTech Connect

    Frazier, T; Adams, P; Fisher, J; Talbot, A

    2011-03-18

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a stadium-sized facility that contains a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for multiple experimental diagnostics. NIF is the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion (ICF) and matter at extreme energy densities and pressures. NIF's laser beams are designed to compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. 2,500 servers, 400 network devices and 700 terabytes of networked attached storage provide the foundation for NIF's Integrated Computer Control System (ICCS) and Experimental Data Archive. This talk discusses the rationale & benefits for server virtualization in the context of an operational experimental facility, the requirements discovery process used by the NIF teams to establish evaluation criteria for virtualization alternatives, the processes and procedures defined to enable virtualization of servers in a timeframe that did not delay the execution of experimental campaigns and the lessons the NIF teams learned along the way. The virtualization architecture ultimately selected for ICCS is based on the Open Source Xen computing platform and 802.1Q open networking standards. The specific server and network configurations needed to ensure performance and high availability of the control system infrastructure will be discussed.

  10. Brain-computer interface control along instructed paths

    NASA Astrophysics Data System (ADS)

    Sadtler, P. T.; Ryu, S. I.; Tyler-Kabara, E. C.; Yu, B. M.; Batista, A. P.

    2015-02-01

    Objective. Brain-computer interfaces (BCIs) are being developed to assist paralyzed people and amputees by translating neural activity into movements of a computer cursor or prosthetic limb. Here we introduce a novel BCI task paradigm, intended to help accelerate improvements to BCI systems. Through this task, we can push the performance limits of BCI systems, we can quantify more accurately how well a BCI system captures the user’s intent, and we can increase the richness of the BCI movement repertoire. Approach. We have implemented an instructed path task, wherein the user must drive a cursor along a visible path. The instructed path task provides a versatile framework to increase the difficulty of the task and thereby push the limits of performance. Relative to traditional point-to-point tasks, the instructed path task allows more thorough analysis of decoding performance and greater richness of movement kinematics. Main results. We demonstrate that monkeys are able to perform the instructed path task in a closed-loop BCI setting. We further investigate how the performance under BCI control compares to native arm control, whether users can decrease their movement variability in the face of a more demanding task, and how the kinematic richness is enhanced in this task. Significance. The use of the instructed path task has the potential to accelerate the development of BCI systems and their clinical translation.

  11. The Effectiveness of Gaze-Contingent Control in Computer Games.

    PubMed

    Orlov, Paul A; Apraksin, Nikolay

    2015-01-01

    Eye-tracking technology and gaze-contingent control in human-computer interaction have become an objective reality. This article reports on a series of eye-tracking experiments, in which we concentrated on one aspect of gaze-contingent interaction: Its effectiveness compared with mouse-based control in a computer strategy game. We propose a measure for evaluating the effectiveness of interaction based on "the time of recognition" the game unit. In this article, we use this measure to compare gaze- and mouse-contingent systems, and we present the analysis of the differences as a function of the number of game units. Our results indicate that performance of gaze-contingent interaction is typically higher than mouse manipulation in a visual searching task. When tested on 60 subjects, the results showed that the effectiveness of gaze-contingent systems over 1.5 times higher. In addition, we obtained that eye behavior stays quite stabile with or without mouse interaction. PMID:26562927

  12. Brain-computer interface control along instructed paths

    PubMed Central

    Sadtler, P T; Ryu, S I; Tyler-Kabara, E C; Yu, B M; Batista, A P

    2015-01-01

    Objective Brain-computer interfaces (BCIs) are being developed to assist paralyzed people and amputees by translating neural activity into movements of a computer cursor or prosthetic limb. Here we introduce a novel BCI task paradigm, intended to help accelerate improvements to BCI systems. Through this task, we can push the performance limits of BCI systems, we can quantify more accurately how well a BCI system captures the user’s intent, and we can increase the richness of the BCI movement repertoire. Approach We have implemented an instructed path task, wherein the user must drive a cursor along a visible path. The instructed path task provides a versatile framework to increase the difficulty of the task and thereby push the limits of performance. Relative to traditional point-to-point tasks, the instructed path task allows more thorough analysis of decoding performance and greater richness of movement kinematics. Main results We demonstrate that monkeys are able to perform the instructed path task in a closed-loop BCI setting. We further investigate how the performance under BCI control compares to native arm control, whether users can decrease their movement variability in the face of a more demanding task, and how the kinematic richness is enhanced in this task. Significance The use of the instructed path task has the potential to accelerate the development of BCI systems and their clinical translation. PMID:25605498

  13. Secure Dynamic access control scheme of PHR in cloud computing.

    PubMed

    Chen, Tzer-Shyong; Liu, Chia-Hui; Chen, Tzer-Long; Chen, Chin-Sheng; Bau, Jian-Guo; Lin, Tzu-Ching

    2012-12-01

    With the development of information technology and medical technology, medical information has been developed from traditional paper records into electronic medical records, which have now been widely applied. The new-style medical information exchange system "personal health records (PHR)" is gradually developed. PHR is a kind of health records maintained and recorded by individuals. An ideal personal health record could integrate personal medical information from different sources and provide complete and correct personal health and medical summary through the Internet or portable media under the requirements of security and privacy. A lot of personal health records are being utilized. The patient-centered PHR information exchange system allows the public autonomously maintain and manage personal health records. Such management is convenient for storing, accessing, and sharing personal medical records. With the emergence of Cloud computing, PHR service has been transferred to storing data into Cloud servers that the resources could be flexibly utilized and the operation cost can be reduced. Nevertheless, patients would face privacy problem when storing PHR data into Cloud. Besides, it requires a secure protection scheme to encrypt the medical records of each patient for storing PHR into Cloud server. In the encryption process, it would be a challenge to achieve accurately accessing to medical records and corresponding to flexibility and efficiency. A new PHR access control scheme under Cloud computing environments is proposed in this study. With Lagrange interpolation polynomial to establish a secure and effective PHR information access scheme, it allows to accurately access to PHR with security and is suitable for enormous multi-users. Moreover, this scheme also dynamically supports multi-users in Cloud computing environments with personal privacy and offers legal authorities to access to PHR. From security and effectiveness analyses, the proposed PHR access

  14. Simulation Analysis of Computer-Controlled pressurization for Mixture Ratio Control

    NASA Technical Reports Server (NTRS)

    Alexander, Leslie A.; Bishop-Behel, Karen; Benfield, Michael P. J.; Kelley, Anthony; Woodcock, Gordon R.

    2005-01-01

    A procedural code (C++) simulation was developed to investigate potentials for mixture ratio control of pressure-fed spacecraft rocket propulsion systems by measuring propellant flows, tank liquid quantities, or both, and using feedback from these measurements to adjust propellant tank pressures to set the correct operating mixture ratio for minimum propellant residuals. The pressurization system eliminated mechanical regulators in favor of a computer-controlled, servo- driven throttling valve. We found that a quasi-steady state simulation (pressure and flow transients in the pressurization systems resulting from changes in flow control valve position are ignored) is adequate for this purpose. Monte-Carlo methods are used to obtain simulated statistics on propellant depletion. Mixture ratio control algorithms based on proportional-integral-differential (PID) controller methods were developed. These algorithms actually set target tank pressures; the tank pressures are controlled by another PID controller. Simulation indicates this approach can provide reductions in residual propellants.

  15. Cryogenic Control Architecture for Large-Scale Quantum Computing

    NASA Astrophysics Data System (ADS)

    Hornibrook, J. M.; Colless, J. I.; Conway Lamb, I. D.; Pauka, S. J.; Lu, H.; Gossard, A. C.; Watson, J. D.; Gardner, G. C.; Fallahi, S.; Manfra, M. J.; Reilly, D. J.

    2015-02-01

    Solid-state qubits have recently advanced to the level that enables them, in principle, to be scaled up into fault-tolerant quantum computers. As these physical qubits continue to advance, meeting the challenge of realizing a quantum machine will also require the development of new supporting devices and control architectures with complexity far beyond the systems used in today's few-qubit experiments. Here, we report a microarchitecture for controlling and reading out qubits during the execution of a quantum algorithm such as an error-correcting code. We demonstrate the basic principles of this architecture using a cryogenic switch matrix implemented via high-electron-mobility transistors and a new kind of semiconductor device based on gate-switchable capacitance. The switch matrix is used to route microwave waveforms to qubits under the control of a field-programmable gate array, also operating at cryogenic temperatures. Taken together, these results suggest a viable approach for controlling large-scale quantum systems using semiconductor technology.

  16. Mechanical and dosimetric quality control for computer controlled radiotherapy treatment equipment.

    PubMed

    Thompson, A V; Lam, K L; Balter, J M; McShan, D L; Martel, M K; Weaver, T A; Fraass, B A; Ten Haken, R K

    1995-05-01

    Modern computer controlled radiotherapy treatment equipment offers the possibility of delivering complex, multiple field treatments with minimal operator intervention, thus making multiple field conformal therapy practical. Conventional quality control programs are inadequate for this new technology, so new quality control procedures are needed. A reasonably fast, sensitive, and complete daily quality control program has been developed in our clinic that includes nearly automated mechanical as well as dosimetric tests. Automated delivery of these quality control fields is performed by the control system of the MM50 racetrack microtron, directed by the CCRS sequence processor [D. L. McShan and B. A. Fraass, Proceedings of the XIth International Conference on the use of computers in Radiation Therapy, 20-24 March 1994, Manchester, U.K. (North Western Medical Physics Department, Manchester, U.K., 1994), pp. 210-211], which controls the treatment process. The mechanical tests involve multiple irradiations of a single film to check the accuracy and reproducibility of the computer controlled setup of gantry and collimator angles, table orientation, collimator jaws, and multileaf collimator shape. The dosimetric tests, which involve multiple irradiations of an array of ionization chambers in a commercial dose detector (Keithly model 90100 Tracker System) rigidly attached to the head of the treatment gantry, check the output and symmetry of the treatment unit as a function of gantry and collimator angle and other parameters. For each of the dosimetric tests, readings from the five ionization chambers are automatically read out, stored, and analyzed by the computer, along with the geometric parameters of the treatment unit for that beam.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7643792

  17. Soft tissue-preserving computer-aided impression: a novel concept using ultrasonic 3D-scanning.

    PubMed

    Vollborn, Thorsten; Habor, Daniel; Pekam, Fabrice Chuembou; Heger, Stefan; Marotti, Juliana; Reich, Sven; Wolfart, Stefan; Tinschert, Joachim; Radermacher, Klaus

    2014-01-01

    Subgingival preparations are often affected by blood and saliva during impression taking, regardless of whether one is using compound impression techniques or intraoral digital scanning methods. The latter are currently based on optical principles and therefore also need clean and dry surfaces. In contrast, ultrasonic waves are able to non-invasively penetrate gingiva, saliva, and blood, leading to decisive advantages, as cleaning and drying of the oral cavity becomes unnecessary. In addition, the application of ultrasound may facilitate the detection of subgingival structures without invasive manipulation, thereby reducing the risk of secondary infection and treatment time, and increasing patient comfort. Ultrasound devices commonly available for medical application and for the testing of materials are only suitable to a limited extent, as their resolution, precision, and design do not fulfill the requirements for intraoral scanning. The aim of this article is to describe the development of a novel ultrasound technology that enables soft tissue-preserving digital impressions of preparations for the CAD/CAM-based production of dental prostheses. The concept and development of the high-resolution ultrasound technique and the corresponding intraoral scanning system, as well as the integration into the CAD/CAM process chain, is presented. PMID:25643460

  18. Emulation of computer mouse control with a noninvasive brain-computer interface

    PubMed Central

    McFarland, Dennis J.; Krusienski, Dean J.; Sarnacki, William A.; Wolpaw, Jonathan R.

    2009-01-01

    Brain-computer interface (BCI) technology can provide nonmuscular communication and control to people who are severely paralyzed. BCIs can use noninvasive or invasive techniques for recording the brain signals that convey the user’s commands. Although noninvasive BCIs are used for simple applications, it has frequently been assumed that only invasive BCIs, which use electrodes implanted in the brain, will be able to provide multidimensional sequential control of a robotic arm or a neuroprosthesis. The present study shows that a noninvasive BCI using scalp-recorded EEG activity and an adaptive algorithm can provide people, including people with spinal cord injuries, with two-dimensional cursor movement and target selection. Multiple targets were presented around the periphery of a computer screen, with one designated as the correct target. The user’s task was to use EEG to move a cursor from the center the screen to the correct target and then to use an additional EEG feature to select the target. If the cursor reached an incorrect target, the user was instructed not to select it. Thus, this task emulated the key features of mouse operation. The results indicate that people with severe motor disabilities could use brain signals for sequential multidimensional movement and selection. PMID:18367779

  19. Proceedings of the Workshop on Computational Aspects in the Control of Flexible Systems, part 1

    NASA Technical Reports Server (NTRS)

    Taylor, Lawrence W., Jr. (Compiler)

    1989-01-01

    Control/Structures Integration program software needs, computer aided control engineering for flexible spacecraft, computer aided design, computational efficiency and capability, modeling and parameter estimation, and control synthesis and optimization software for flexible structures and robots are among the topics discussed.

  20. Multimedia computer support for a course in ground control

    SciTech Connect

    Summers, D.A.; Unal, A.

    1996-12-31

    A prototype multimedia compact disc (CD) was created using the facilities at the Rock Mechanics and Explosives Research Center (RMERC) of the University of Missouri-Rolla (UMR) to teach a portion of a course in Ground Control. Multimedia computers offer an environment where audio-visual presentations can be made in an interactive fashion. Together with relevant animation clips, video clips, and 3-D representations, the difficulties in describing mining processes and earth structures can be overcome. This paper describes the experience gained in preparing interactive multimedia lectures on computers. The hardware and software used in creating the sound commentary, 3-D graphics, animation clips, video clips, and movies are listed. The structure of the program and how interactivity was achieved is explained in detail. Such an instructional tool is not only an excellent supplement to regular courses but it also is an inexpensive and effective way of providing distance education for mining engineers working at remote locations scattered all over the country.

  1. Trace contaminant control simulation computer program, version 8.1

    NASA Technical Reports Server (NTRS)

    Perry, J. L.

    1994-01-01

    The Trace Contaminant Control Simulation computer program is a tool for assessing the performance of various process technologies for removing trace chemical contamination from a spacecraft cabin atmosphere. Included in the simulation are chemical and physical adsorption by activated charcoal, chemical adsorption by lithium hydroxide, absorption by humidity condensate, and low- and high-temperature catalytic oxidation. Means are provided for simulating regenerable as well as nonregenerable systems. The program provides an overall mass balance of chemical contaminants in a spacecraft cabin given specified generation rates. Removal rates are based on device flow rates specified by the user and calculated removal efficiencies based on cabin concentration and removal technology experimental data. Versions 1.0 through 8.0 are documented in NASA TM-108409. TM-108409 also contains a source file listing for version 8.0. Changes to version 8.0 are documented in this technical memorandum and a source file listing for the modified version, version 8.1, is provided. Detailed descriptions for the computer program subprograms are extracted from TM-108409 and modified as necessary to reflect version 8.1. Version 8.1 supersedes version 8.0. Information on a separate user's guide is available from the author.

  2. Cell sorting in a Petri dish controlled by computer vision

    PubMed Central

    Környei, Z.; Beke, S.; Mihálffy, T.; Jelitai, M.; Kovács, K. J.; Szabó, Z.; Szabó, B.

    2013-01-01

    Fluorescence-activated cell sorting (FACS) applying flow cytometry to separate cells on a molecular basis is a widespread method. We demonstrate that both fluorescent and unlabeled live cells in a Petri dish observed with a microscope can be automatically recognized by computer vision and picked up by a computer-controlled micropipette. This method can be routinely applied as a FACS down to the single cell level with a very high selectivity. Sorting resolution, i.e., the minimum distance between two cells from which one could be selectively removed was 50–70 micrometers. Survival rate with a low number of 3T3 mouse fibroblasts and NE-4C neuroectodermal mouse stem cells was 66±12% and 88±16%, respectively. Purity of sorted cultures and rate of survival using NE-4C/NE-GFP-4C co-cultures were 95±2% and 62±7%, respectively. Hydrodynamic simulations confirmed the experimental sorting efficiency and a cell damage risk similar to that of normal FACS. PMID:23336070

  3. Computational optimization of a pneumatic forebody flow control concept

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Tavella, Domingo; Schiff, Lewis B.

    1991-01-01

    The effectiveness of a tangential slot blowing concept for generating lateral control forces on an aircraft forebody is analyzed using computational fluid dynamics. The flow about a fighter forebody is computed using a multiple-zone, thin-layer Navier-Stokes code. Tangential slot blowing is modeled by the use of an actuator plane. The effects of slot location and slot length on the efficiency of the system are analyzed. Results of the study indicate that placement of the slot near the nose of the aircraft greatly enhances the efficiency of the system, while the length and circumferential location of the slot are of secondary importance. Efficiency is defined by the amount of side force or yawing moment obtained per unit blowing coefficient. The effect of sideslip on the system is also analyzed. The system is able to generate incremental changes in forces and moments in flows with sideslip angles up to 10 deg comparable to those obtained at zero sideslip. These results are used to determine a baseline configuration for an experimental study of the tangential slot blowing concept.

  4. Computational Analysis of Cryogenic Flow Through a Control Valve

    NASA Technical Reports Server (NTRS)

    Danes, Russell; Woods, Jody; Sulyma, Peter

    2003-01-01

    The initial efforts to develop the capability to model valves used in rocket engine component testing at Stennis Space Center are documented. An axisymmetric model of a control valve with LN2 as the working fluid was developed. The goal was to predict the effect of change in the plug/sear region of the valve prior to testing. The valve flow coefficient was predicted for a range of plug positions. Verification of the calculations was carried out to quantify the uncertainty in the numerical answer. The modeled results compared well qualitatively to experimental trends. Additionally, insights into the flow processes in the valve were obtained. Benefits from the verification process included the ability to use coarser grids and insight into ways to reduce computational time by using double precision accuracy and non-integer grid ratios. Future valve modeling activities will include shape optimization of the valve/seat region and dynamic grid modeling.

  5. Carbon nanofiber electrodes and controlled nanogaps for scanning electrochemical microscopy experiments.

    PubMed

    Tel-Vered, Ran; Walsh, Darren A; Mehrgardi, Masoud A; Bard, Allen J

    2006-10-01

    The electrochemical behavior of electrodes made by sealing carbon nanofibers in glass or with electrophoretic paint has been studied by scanning electrochemical microscopy (SECM). Because of their small electroactive surface area, conical geometry with a low aspect ratio and high overpotential for proton and oxygen reduction, carbon nanofiber (CNF) electrodes are promising candidates for producing electrode nanogaps, imaging with high spatial resolution and for the electrodeposition of single metal nanoparticles (e.g., Pt, Pd) for studies as electrocatalysts. By using the feedback mode of the SECM, a CNF tip can produce a gap that is smaller than 20 nm from a platinum disk. Similarly, the SECM used in a tip-collection substrate-generation mode, which subsequently shows a feedback interaction at short distances, makes it possible to detect a single CNF by another CNF and then to form a nanometer gap between the two electrodes. This approach was used to image vertically aligned CNF arrays. This method is useful in the detection in a homogeneous solution of short-lifetime intermediates, which can be electrochemically generated at one electrode and collected at the second at distances that are equivalent to a nanosecond time scale. PMID:17007521

  6. Single Cell Adhesion Assay Using Computer Controlled Micropipette

    PubMed Central

    Salánki, Rita; Hős, Csaba; Orgovan, Norbert; Péter, Beatrix; Sándor, Noémi; Bajtay, Zsuzsa; Erdei, Anna; Horvath, Robert; Szabó, Bálint

    2014-01-01

    Cell adhesion is a fundamental phenomenon vital for all multicellular organisms. Recognition of and adhesion to specific macromolecules is a crucial task of leukocytes to initiate the immune response. To gain statistically reliable information of cell adhesion, large numbers of cells should be measured. However, direct measurement of the adhesion force of single cells is still challenging and today’s techniques typically have an extremely low throughput (5–10 cells per day). Here, we introduce a computer controlled micropipette mounted onto a normal inverted microscope for probing single cell interactions with specific macromolecules. We calculated the estimated hydrodynamic lifting force acting on target cells by the numerical simulation of the flow at the micropipette tip. The adhesion force of surface attached cells could be accurately probed by repeating the pick-up process with increasing vacuum applied in the pipette positioned above the cell under investigation. Using the introduced methodology hundreds of cells adhered to specific macromolecules were measured one by one in a relatively short period of time (∼30 min). We blocked nonspecific cell adhesion by the protein non-adhesive PLL-g-PEG polymer. We found that human primary monocytes are less adherent to fibrinogen than their in vitro differentiated descendants: macrophages and dendritic cells, the latter producing the highest average adhesion force. Validation of the here introduced method was achieved by the hydrostatic step-pressure micropipette manipulation technique. Additionally the result was reinforced in standard microfluidic shear stress channels. Nevertheless, automated micropipette gave higher sensitivity and less side-effect than the shear stress channel. Using our technique, the probed single cells can be easily picked up and further investigated by other techniques; a definite advantage of the computer controlled micropipette. Our experiments revealed the existence of a sub

  7. Brushless DC motor control system responsive to control signals generated by a computer or the like

    NASA Technical Reports Server (NTRS)

    Packard, Douglas T. (Inventor); Schmitt, Donald E. (Inventor)

    1987-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The rotor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor may be regulated by applying a separate control signal to each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  8. Brushless DC motor control system responsive to control signals generated by a computer or the like

    NASA Technical Reports Server (NTRS)

    Packard, D. T. (Inventor)

    1985-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The motor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor be regulated by applying a separate control signal and each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  9. High-speed assembly language (80386/80387) programming for laser spectra scan control and data acquisition providing improved resolution water vapor spectroscopy

    NASA Technical Reports Server (NTRS)

    Allen, Robert J.

    1988-01-01

    An assembly language program using the Intel 80386 CPU and 80387 math co-processor chips was written to increase the speed of data gathering and processing, and provide control of a scanning CW ring dye laser system. This laser system is used in high resolution (better than 0.001 cm-1) water vapor spectroscopy experiments. Laser beam power is sensed at the input and output of white cells and the output of a Fabry-Perot. The assembly language subroutine is called from Basic, acquires the data and performs various calculations at rates greater than 150 faster than could be performed by the higher level language. The width of output control pulses generated in assembly language are 3 to 4 microsecs as compared to 2 to 3.7 millisecs for those generated in Basic (about 500 to 1000 times faster). Included are a block diagram and brief description of the spectroscopy experiment, a flow diagram of the Basic and assembly language programs, listing of the programs, scope photographs of the computer generated 5-volt pulses used for control and timing analysis, and representative water spectrum curves obtained using these programs.

  10. FibroScan (vibration-controlled transient elastography): where does it stand in the United States practice.

    PubMed

    Tapper, Elliot B; Castera, Laurent; Afdhal, Nezam H

    2015-01-01

    With widespread screening and increasingly effective treatments for patients with viral hepatitis as well as the increasing prevalence of nonalcoholic fatty liver disease, the population presenting to the care of gastroenterologists and hepatologists is certain to increase. Assessment of advanced liver disease is traditionally invasive and expensive. Vibration-controlled transient elastography, commonly delivered by the FibroScan device, is an option recently approved by the Food and Drug Administration for the noninvasive assessment of liver disease at the point of care. Herein, we review the promise and pitfalls of vibration-controlled transient elastography with the aim of providing clinicians with a framework to interpret its results and apply this technology to the changing needs of our patients. PMID:24909907

  11. Imaging of enzyme activity by scanning electrochemical microscope equipped with a feedback control for substrate-probe distance.

    PubMed

    Oyamatsu, Daisuke; Hirano, Yu; Kanaya, Norihiro; Mase, Yoshiaki; Nishizawa, Matsuhiko; Matsue, Tomokazu

    2003-08-01

    The enzymatic activity of diaphorase (Dp) immobilized on a solid substrate was characterized using a scanning electrochemical microscope (SECM) with shear force feedback to control the substrate-probe distance. The shear force between the substrate and the probe was monitored with a tuning fork-type quartz crystal and used as the feedback control to set the microelectrode probe close to the substrate surface. The sensitivity and the contrast of the SECM image were improved in the constant distance mode (distance, 50 nm) with the shear force feedback compared to the image in the constant height mode without the feedback. By using this system, the SECM and topographic images of the immobilized diaphorase were simultaneously measured. The microelectrode tip used in this study was ground aslant like a syringe needle in order to obtain the shaper topographic images. This shape was also effective for avoiding the interference during the diffusion of the enzyme substrates. PMID:12893317

  12. A computer-controlled multi-electrode switch.

    PubMed

    Santos, F J; Santos, M S

    1999-01-01

    A computer-actuated switch was built to control, simultaneously, two automatic titration assemblies each consisting of an electrode pair and a burette, and using only one measuring device. This switch is modular, simple and versatile allowing easy adaptation and expansion; apart from its application in multiple-titration systems, this device can also be used for standard addition analysis and multi-component analysis using ion-selective electrodes (ISE). The repeatability as well as the accuracy of the measurements made with this switch were ensured using high-quality relays, and very high electrical insulation, attained through the use of two separate printed circuit boards (pcb) of good quality and careful design of these pcbs. This low-cost multi-electrode switch is controlled through the parallel port of a PC that collects the data via an inexpensive 12-bit ADC board (8-bit ISA type), and is easily programmable in any high-level language. This type of device allows the collection of a large amount of data in relatively short periods, which can be analysed later allowing the choice of the best compromise of time versus accuracy for the study of any particular system. PMID:18924850

  13. Design of a new high precision computer numerical control

    SciTech Connect

    Sweeney, D.J.; Weinert, G.F.

    1988-06-23

    The purpose of this project is to produce a generic high precision computer numerical controller (CNC) for use on microinch- and sub-microinch-resolution machine tools at the Lawrence Livermore National Laboratory. In order to fully utilize the potential of these machine tools, the CNC must include the ability to use multiple feedback sensors on each machine axis, incorporate corrections for quasistatic geometric errors (such as straightness, and squareness), be able to function over a relatively large range of motion (in excess of 60 inches per axis), and be able to produce motion updates at a rate sufficient to take advantage of the high bandwidth of the servo systems. At present, no commercially available CNC can presently meet all of the resolution, feed rate, and length of travel requirements of these machines. In order to minimize the complexity of the system, and thereby increase its reliability and maintainability, the programming was done in a high level language. The number of processors was kept as small as possible while still maintaining the performance requirements. We also used commercially available hardware in preference to building, in order to increase both reliability and maintainability. Special emphasis was given to making the CNC's operator interface as friendly as possible. We have completed a prototype control. We plan to install and test it in 1988. 4 figs.

  14. Synchronized computational architecture for generalized bilateral control of robot arms

    NASA Technical Reports Server (NTRS)

    Szakaly, Zoltan F. (Inventor)

    1991-01-01

    A master six degree of freedom Force Reflecting Hand Controller (FRHC) is available at a master site where a received image displays, in essentially real time, a remote robotic manipulator which is being controlled in the corresponding six degree freedom by command signals which are transmitted to the remote site in accordance with the movement of the FRHC at the master site. Software is user-initiated at the master site in order to establish the basic system conditions, and then a physical movement of the FRHC in Cartesean space is reflected at the master site by six absolute numbers that are sensed, translated and computed as a difference signal relative to the earlier position. The change in position is then transmitted in that differential signal form over a high speed synchronized bilateral communication channel which simultaneously returns robot-sensed response information to the master site as forces applied to the FRHC so that the FRHC reflects the feel of what is taking place at the remote site. A system wide clock rate is selected at a sufficiently high rate that the operator at the master site experiences the Force Reflecting operation in real time.

  15. Scanning to the Beep: A Teacher-Tested Computer-Based Observational Assessment Tool for the Distance Education Classroom.

    ERIC Educational Resources Information Center

    Hausafus, Cheryl O.; Torrie, Margaret

    1995-01-01

    Discusses results of a study that examined preservice and inservice teachers' use of hand-held Computer-Based Observational Assessment Tools (CBOATs) in a distance education environment using the Iowa Communications Network. The CBOAT studied was Learner Profile, which included a small bar-code reader and data management software. (LRW)

  16. A digital computer propulsion control facility: Description of capabilities and summary of experimental program results

    NASA Technical Reports Server (NTRS)

    Zeller, J. R.; Arpasi, D. J.; Lehtinen, B.

    1976-01-01

    Flight weight digital computers are being used today to carry out many of the propulsion system control functions previously delegated exclusively to hydromechanical controllers. An operational digital computer facility for propulsion control mode studies has been used successfully in several experimental programs. This paper describes the system and some of the results concerned with engine control, inlet control, and inlet engine integrated control. Analytical designs for the digital propulsion control modes include both classical and modern/optimal techniques.

  17. Commissioning dose computation models for spot scanning proton beams in water for a commercially available treatment planning system

    PubMed Central

    Zhu, X. R.; Poenisch, F.; Lii, M.; Sawakuchi, G. O.; Titt, U.; Bues, M.; Song, X.; Zhang, X.; Li, Y.; Ciangaru, G.; Li, H.; Taylor, M. B.; Suzuki, K.; Mohan, R.; Gillin, M. T.; Sahoo, N.

    2013-01-01

    Purpose: To present our method and experience in commissioning dose models in water for spot scanning proton therapy in a commercial treatment planning system (TPS). Methods: The input data required by the TPS included in-air transverse profiles and integral depth doses (IDDs). All input data were obtained from Monte Carlo (MC) simulations that had been validated by measurements. MC-generated IDDs were converted to units of Gy mm2/MU using the measured IDDs at a depth of 2 cm employing the largest commercially available parallel-plate ionization chamber. The sensitive area of the chamber was insufficient to fully encompass the entire lateral dose deposited at depth by a pencil beam (spot). To correct for the detector size, correction factors as a function of proton energy were defined and determined using MC. The fluence of individual spots was initially modeled as a single Gaussian (SG) function and later as a double Gaussian (DG) function. The DG fluence model was introduced to account for the spot fluence due to contributions of large angle scattering from the devices within the scanning nozzle, especially from the spot profile monitor. To validate the DG fluence model, we compared calculations and measurements, including doses at the center of spread out Bragg peaks (SOBPs) as a function of nominal field size, range, and SOBP width, lateral dose profiles, and depth doses for different widths of SOBP. Dose models were validated extensively with patient treatment field-specific measurements. Results: We demonstrated that the DG fluence model is necessary for predicting the field size dependence of dose distributions. With this model, the calculated doses at the center of SOBPs as a function of nominal field size, range, and SOBP width, lateral dose profiles and depth doses for rectangular target volumes agreed well with respective measured values. With the DG fluence model for our scanning proton beam line, we successfully treated more than 500 patients from

  18. Commissioning dose computation models for spot scanning proton beams in water for a commercially available treatment planning system

    SciTech Connect

    Zhu, X. R.; Poenisch, F.; Lii, M.; Sawakuchi, G. O.; Titt, U.; Bues, M.; Song, X.; Zhang, X.; Li, Y.; Ciangaru, G.; Li, H.; Taylor, M. B.; Suzuki, K.; Mohan, R.; Gillin, M. T.; Sahoo, N.

    2013-04-15

    Purpose: To present our method and experience in commissioning dose models in water for spot scanning proton therapy in a commercial treatment planning system (TPS). Methods: The input data required by the TPS included in-air transverse profiles and integral depth doses (IDDs). All input data were obtained from Monte Carlo (MC) simulations that had been validated by measurements. MC-generated IDDs were converted to units of Gy mm{sup 2}/MU using the measured IDDs at a depth of 2 cm employing the largest commercially available parallel-plate ionization chamber. The sensitive area of the chamber was insufficient to fully encompass the entire lateral dose deposited at depth by a pencil beam (spot). To correct for the detector size, correction factors as a function of proton energy were defined and determined using MC. The fluence of individual spots was initially modeled as a single Gaussian (SG) function and later as a double Gaussian (DG) function. The DG fluence model was introduced to account for the spot fluence due to contributions of large angle scattering from the devices within the scanning nozzle, especially from the spot profile monitor. To validate the DG fluence model, we compared calculations and measurements, including doses at the center of spread out Bragg peaks (SOBPs) as a function of nominal field size, range, and SOBP width, lateral dose profiles, and depth doses for different widths of SOBP. Dose models were validated extensively with patient treatment field-specific measurements. Results: We demonstrated that the DG fluence model is necessary for predicting the field size dependence of dose distributions. With this model, the calculated doses at the center of SOBPs as a function of nominal field size, range, and SOBP width, lateral dose profiles and depth doses for rectangular target volumes agreed well with respective measured values. With the DG fluence model for our scanning proton beam line, we successfully treated more than 500 patients

  19. Scintigraphic thyroid abnormalities after radiation. A controlled study with /sup 99m/Tc pertechnetate scanning

    SciTech Connect

    Gonzalez-Villalpando, C.; Frohman, L.A.; Bekerman, C.; Favus, M.J.; Pinsky, S.; Ryo, U.Y.; Shore-Freedman, E.; Schneider, A.B.

    1982-07-01

    We did /sup 99/mTc-pertechnetate thyroid scintigraphy on 99 subjects with no history of therapeutic irradiation to the head or neck. They were compared with 198 irradiated patients selected from a group of over 1700 who were evaluated because of radiation treatment for benign head and neck conditions during childhood. The two groups were similar with respect to age and sex distribution. There were significantly more abnormal scintigrams in the irradiated group (55 of 198 patients versus one of 99 controls). Even after patients and controls with palpable nodules were excluded from the analysis there were still more abnormal scintigrams in the irradiated group (16 of 150 irradiated versus one of 97 control subjects). We conclude that thyroid nodules, including the smaller, nonpalpable nodules discovered by scintigraphy, are related to previous radiation therapy. For persons at substantial risk, such as those who received high-dose treatment (greater than 700 R) during childhood, the data support the use of screening scintigraphy, even with normal findings on palpation.

  20. WBC scan

    MedlinePlus

    ... in the body. It is a type of nuclear scan . How the Test is Performed Blood will ... radiation. Due to the slight radiation exposure, most nuclear scans (including WBC scan) are not recommended for ...

  1. Nuclear Scans

    MedlinePlus

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  2. Differentiation of the ILO boundary chest roentgenograph (0/1 to 1/0) in asbestosis by high-resolution computed tomography scan, alveolitis, and respiratory impairment.

    PubMed

    Harkin, T J; McGuinness, G; Goldring, R; Cohen, H; Parker, J E; Crane, M; Naidich, D P; Rom, W N

    1996-01-01

    High-resolution computed tomography (HRCT) scans have been advocated as providing greater sensitivity in detecting parenchymal opacities in asbestos-exposed individuals, especially in the presence of pleural fibrosis, and having excellent inter- and intraobserver reader interpretation. We compared the 1980 International Labor Organization (ILO) International Classification of the Radiographs of the Pneumoconioses for asbestosis with the high-resolution CT scan using a grid scoring system to better differentiate normal versus abnormal in the ILO boundary 0/1 to 1/0 chest roentgenograph. We studied 37 asbestos-exposed individuals using the ILO classification, HRCT grid scores, respiratory symptom questionnaires, pulmonary function tests, and bronchoalveolar lavage. We used Pearson correlation coefficients to evaluate the linear relationship between outcome variables and each roentgenographic method. The normal HRCT scan proved to be an excellent predictor of "normality," with pulmonary function values close to 100% for forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), total lung capacity (TLC), and carbon monoxide diffusing capacity (DLCO) and no increase in BAL inflammatory cells. Concordant HRCT/ILO abnormalities were associated with reduced FEV1/FVC ratio, reduced diffusing capacity, and alveolitis consistent with a definition of asbestosis. In our study, the ILO classification and HRCT grid scores were both excellent modalities for the assessment of asbestosis and its association with impaired physiology and alveolitis, with their combined use providing statistical associations with alveolitis and reduced diffusing capacity. PMID:8871331

  3. Analysis and control of computer cooling fan noise

    NASA Astrophysics Data System (ADS)

    Wong, Kam

    This thesis is divided into three parts: the study of the source mechanisms and their separation, passive noise control, and active noise control. The mechanisms of noise radiated by a typical computer cooling fan is investigated both theoretically and experimentally focusing on the dominant rotor-stator interaction. The unsteady force generated by the aerodynamic interaction between the rotor blades and struts is phase locked with the blade rotation and radiates tonal noise. Experimentally, synchronous averaging with the rotation signal extracts the tones made by the deterministic part of the rotor-strut interaction mechanism. This averaged signal is called the rotary noise. The difference between the overall noise and rotary noise is defined as random noise which is broadband in the spectrum. The deterministic tonal peaks are certainly more annoying than the broadband, so the suppression of the tones is the focus of this study. Based on the theoretical study of point force formulation, methods are devised to separate the noise radiated by the two components of drag and thrust forces on blades and struts. The source separation is also extended to the leading and higher order modes of the spinning pressure pattern. By using the original fan rotor and installing it in various casings, the noise sources of the original fan are decomposed into elementary sources through directivity measurements. Details of the acoustical directivity for the original fan and its various modifications are interpreted. For the sample fan, two common features account for most of the tonal noise radiated. The two features are the inlet flow distortion caused by the square fan casing, and the large strut carrying the electric wires for the motor. When the inlet bellmouth is installed and the large strut is trimmed down to size, a significant reduction of 12 dB in tonal sound power is achieved. These structural corrections constitute the passive noise control. However, the end product still

  4. Reduced state feedback gain computation. [optimization and control theory for aircraft control

    NASA Technical Reports Server (NTRS)

    Kaufman, H.

    1976-01-01

    Because application of conventional optimal linear regulator theory to flight controller design requires the capability of measuring and/or estimating the entire state vector, it is of interest to consider procedures for computing controls which are restricted to be linear feedback functions of a lower dimensional output vector and which take into account the presence of measurement noise and process uncertainty. Therefore, a stochastic linear model that was developed is presented which accounts for aircraft parameter and initial uncertainty, measurement noise, turbulence, pilot command and a restricted number of measurable outputs. Optimization with respect to the corresponding output feedback gains was performed for both finite and infinite time performance indices without gradient computation by using Zangwill's modification of a procedure originally proposed by Powell. Results using a seventh order process show the proposed procedures to be very effective.

  5. Measurement and Control of the Variability of Scanning Pressure Transducer Measurements

    NASA Technical Reports Server (NTRS)

    Kuhl, David D.; Everhart, Joel L.; Hallissy, James B.

    2003-01-01

    This paper describes the new wall pressure measurement system and data-quality monitoring software installed at 14x22 Ft subsonic tunnel at the NASA Langley Research Center. The monitoring software was developed to enable measurement and control of the variability of the reference pressures and approximately 400 tunnel wall pressure measurements. Variability of the system, based upon data acquired over a year of wind tunnel tests and calibrations, is presented. The level of variation of the wall pressure measurements is shown to be predictable.

  6. A Command of PASCAL Will Help Kids Control Computers.

    ERIC Educational Resources Information Center

    dePillis, S. E.

    1984-01-01

    Argues against using prepared computer programs for school instruction and proposes PASCAL as the most instructionally apt choice for a first computer language. Includes tips on resources for teacher training and textbooks in PASCAL. (JW)

  7. Assessment of CT numbers in limited and medium field-of-view scans taken using Accuitomo 170 and Veraviewepocs 3De cone-beam computed tomography scanners

    PubMed Central

    Oliveira, Matheus L.; Tosoni, Guilherme M.; Lindsey, David H.; Mendoza, Kristopher; Tetradis, Sotirios

    2014-01-01

    Purpose To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Materials and Methods Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K2HPO4 solutions were measured. The relationship between CT number and K2HPO4 concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. Results The relationship between K2HPO4 concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. Conclusion There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship. PMID:25473635

  8. Manufacturing models of fetal malformations built from 3-dimensional ultrasound, magnetic resonance imaging, and computed tomography scan data.

    PubMed

    Werner, Heron; Rolo, Liliam Cristine; Araujo Júnior, Edward; Dos Santos, Jorge Roberto Lopes

    2014-03-01

    Technological innovations accompanying advances in medicine have given rise to the possibility of obtaining better-defined fetal images that assist in medical diagnosis and contribute toward genetic counseling offered to parents during the prenatal period. In this article, we show our innovative experience of diagnosing fetal malformations through correlating 3-dimensional ultrasonography, magnetic resonance imaging, and computed tomography, which are accurate techniques for fetal assessment, with a fetal image reconstruction technique to create physical fetal models. PMID:24901782

  9. Short-Range Six-Axis Interferometer Controlled Positioning for Scanning Probe Microscopy

    PubMed Central

    Lazar, Josef; Klapetek, Petr; Valtr, Miroslav; Hrabina, Jan; Buchta, Zdenek; Cip, Onrej; Cizek, Martin; Oulehla, Jindrich; Sery, Mojmir

    2014-01-01

    We present a design of a nanometrology measuring setup which is a part of the national standard instrumentation for nanometrology operated by the Czech Metrology Institute (CMI) in Brno, Czech Republic. The system employs a full six-axis interferometric position measurement of the sample holder consisting of six independent interferometers. Here we report on description of alignment issues and accurate adjustment of orthogonality of the measuring axes. Consequently, suppression of cosine errors and reduction of sensitivity to Abbe offset is achieved through full control in all six degrees of freedom. Due to the geometric configuration including a wide basis of the two units measuring in y-direction and the three measuring in z-direction the angle resolution of the whole setup is minimize to tens of nanoradians. Moreover, the servo-control of all six degrees of freedom allows to keep guidance errors below 100 nrad. This small range system is based on a commercial nanopositioning stage driven by piezoelectric transducers with the range (200 × 200 × 10) μm. Thermally compensated miniature interferometric units with fiber-optic light delivery and integrated homodyne detection system were developed especially for this system and serve as sensors for othogonality alignment. PMID:24451463

  10. Lung Texture in Serial Thoracic Computed Tomography Scans: Correlation of Radiomics-based Features With Radiation Therapy Dose and Radiation Pneumonitis Development

    SciTech Connect

    Cunliffe, Alexandra; Armato, Samuel G.; Castillo, Richard; Pham, Ngoc; Guerrero, Thomas; Al-Hallaq, Hania A.

    2015-04-01

    Purpose: To assess the relationship between radiation dose and change in a set of mathematical intensity- and texture-based features and to determine the ability of texture analysis to identify patients who develop radiation pneumonitis (RP). Methods and Materials: A total of 106 patients who received radiation therapy (RT) for esophageal cancer were retrospectively identified under institutional review board approval. For each patient, diagnostic computed tomography (CT) scans were acquired before (0-168 days) and after (5-120 days) RT, and a treatment planning CT scan with an associated dose map was obtained. 32- × 32-pixel regions of interest (ROIs) were randomly identified in the lungs of each pre-RT scan. ROIs were subsequently mapped to the post-RT scan and the planning scan dose map by using deformable image registration. The changes in 20 feature values (ΔFV) between pre- and post-RT scan ROIs were calculated. Regression modeling and analysis of variance were used to test the relationships between ΔFV, mean ROI dose, and development of grade ≥2 RP. Area under the receiver operating characteristic curve (AUC) was calculated to determine each feature's ability to distinguish between patients with and those without RP. A classifier was constructed to determine whether 2- or 3-feature combinations could improve RP distinction. Results: For all 20 features, a significant ΔFV was observed with increasing radiation dose. Twelve features changed significantly for patients with RP. Individual texture features could discriminate between patients with and those without RP with moderate performance (AUCs from 0.49 to 0.78). Using multiple features in a classifier, AUC increased significantly (0.59-0.84). Conclusions: A relationship between dose and change in a set of image-based features was observed. For 12 features, ΔFV was significantly related to RP development. This study demonstrated the ability of radiomics to provide a quantitative, individualized

  11. Lung Texture in Serial Thoracic Computed Tomography Scans: Correlation of Radiomics-based Features With Radiation Therapy Dose and Radiation Pneumonitis Development

    PubMed Central

    Cunliffe, Alexandra; Armato, Samuel G.; Castillo, Richard; Pham, Ngoc; Guerrero, Thomas; Al-Hallaq, Hania A.

    2015-01-01

    Purpose To assess the relationship between radiation dose and change in a set of mathematical intensity- and texture-based features and to determine the ability of texture analysis to identify patients who develop radiation pneumonitis (RP). Methods and Materials A total of 106 patients who received radiation therapy (RT) for esophageal cancer were retrospectively identified under institutional review board approval. For each patient, diagnostic computed tomography (CT) scans were acquired before (0–168 days) and after (5–120 days) RT, and a treatment planning CT scan with an associated dose map was obtained. 32- × 32-pixel regions of interest (ROIs) were randomly identified in the lungs of each pre-RT scan. ROIs were subsequently mapped to the post-RT scan and the planning scan dose map by using deformable image registration. The changes in 20 feature values (ΔFV) between pre- and post-RT scan ROIs were calculated. Regression modeling and analysis of variance were used to test the relationships between ΔFV, mean ROI dose, and development of grade ≥2 RP. Area under the receiver operating characteristic curve (AUC) was calculated to determine each feature’s ability to distinguish between patients with and those without RP. A classifier was constructed to determine whether 2- or 3-feature combinations could improve RP distinction. Results For all 20 features, a significant ΔFV was observed with increasing radiation dose. Twelve features changed significantly for patients with RP. Individual texture features could discriminate between patients with and those without RP with moderate performance (AUCs from 0.49 to 0.78). Using multiple features in a classifier, AUC increased significantly (0.59–0.84). Conclusions A relationship between dose and change in a set of image-based features was observed. For 12 features, ΔFV was significantly related to RP development. This study demonstrated the ability of radiomics to provide a quantitative, individualized

  12. A computer program for the algebraic determination of control coefficients in Metabolic Control Analysis.

    PubMed

    Thomas, S; Fell, D A

    1993-06-01

    A computer program (MetaCon) is described for the evaluation of flux control, concentration control and branch-point distribution control coefficients of a metabolic pathway. Requiring only the reaction scheme as input, the program produces algebraic expressions for the control coefficients in terms of elasticity coefficients, metabolite concentrations and pathway fluxes. Any of these variables can be substituted by numeric or simple algebraic expressions; the expressions will then be automatically rearranged in terms of the remaining unknown variables. When all variables have been substituted, numeric values will be obtained for the control coefficients. The program is a computerized implementation of the matrix method for the determination of control coefficients. The features of MetaCon are compared with those of other programs available to workers in Metabolic Control Analysis. Potential benefits of, and methods of using, MetaCon are discussed. The mathematical background and validity of the matrix method rules are discussed, and the algorithm used by MetaCon is described. The matrix method is shown to be a specific case of a previously described general formalism for calculating control coefficients. PMID:8503870

  13. Classification Accuracy of Serum Apo A-I and S100B for the Diagnosis of Mild Traumatic Brain Injury and Prediction of Abnormal Initial Head Computed Tomography Scan

    PubMed Central

    Blyth, Brian J.; He, Hua; Mookerjee, Sohug; Jones, Courtney; Kiechle, Karin; Moynihan, Ryan; Wojcik, Susan M.; Grant, William D.; Secreti, LaLainia M.; Triner, Wayne; Moscati, Ronald; Leinhart, August; Ellis, George L.; Khan, Jawwad

    2013-01-01

    Abstract The objective of the current study was to determine the classification accuracy of serum S100B and apolipoprotein (apoA-I) for mild traumatic brain injury (mTBI) and abnormal initial head computed tomography (CT) scan, and to identify ethnic, racial, age, and sex variation in classification accuracy. We performed a prospective, multi-centered study of 787 patients with mTBI who presented to the emergency department within 6 h of injury and 467 controls who presented to the outpatient laboratory for routine blood work. Serum was analyzed for S100B and apoA-I. The outcomes were disease status (mTBI or control) and initial head CT scan. At cutoff values defined by 90% of controls, the specificity for mTBI using S100B (0.899 [95% confidence interval (CI): 0.78–0.92]) was similar to that using apoA-I (0.902 [0.87–0.93]), and the sensitivity using S100B (0.252 [0.22–0.28]) was similar to that using apoA-I (0.249 [0.22–0.28]). The area under the receiver operating characteristic curve (AUC) for the combination of S100B and apoA-I (0.738, 95% CI: 0.71, 0.77), however, was significantly higher than the AUC for S100B alone (0.709, 95% CI: 0.68, 0.74, p=0.001) and higher than the AUC for apoA-I alone (0.645, 95% CI: 0.61, 0.68, p<0.0001). The AUC for prediction of abnormal initial head CT scan using S100B was 0.694 (95%CI: 0.62, 0.77) and not significant for apoA-I. At a S100B cutoff of <0.060 μg/L, the sensitivity for abnormal head CT was 98%, and 22.9% of CT scans could have been avoided. There was significant age and race-related variation in the accuracy of S100B for the diagnosis of mTBI. The combined use of serum S100B and apoA-I maximizes classification accuracy for mTBI, but only S100B is needed to classify abnormal head CT scan. Because of significant subgroup variation in classification accuracy, age and race need to be considered when using S100B to classify subjects for mTBI. PMID:23758329

  14. Proceedings of the Workshop on Computational Aspects in the Control of Flexible Systems, part 2

    NASA Technical Reports Server (NTRS)

    Taylor, Lawrence W., Jr. (Compiler)

    1989-01-01

    The Control/Structures Integration Program, a survey of available software for control of flexible structures, computational efficiency and capability, modeling and parameter estimation, and control synthesis and optimization software are discussed.

  15. Analog computation system for plasma position and shape control

    SciTech Connect

    Haskovec, J.S.; Kellman, A.G.; Moore, C.D.; Strait, E.J.; Taylor, T.S.

    1987-10-01

    Part of the DIII-D upgrade of the Doublet III. Fusion experiment involves incorporation of more extensive feedback control of various plasma parameters. More than 200 sensors and measuring instruments generate the primary analog signals during the experiment. These signals are conditioned and transformed to standard voltages by amplifiers, integrators, and sometimes more complicated circuits. To obtain suitable feedback control variables, subsets of primary signals are combined in the form of mathematical functions. A five-input summing amplifier, a two-input divider/two-input multiplier, and a three-input summing amplifier with a two-input multiplier are the standard module functions. In order to eliminate stability problems in feedback loops, the transfer function of the computing circuits must introduce minimal time delay in the required frequency band, even if multiple cascading is used. Long term stability and accuracy is also required, along with high reliability, to save limited maintenance resources and minimize shutdown time of the experiment. During the initial stage of implementation, high flexibility in the circuit configuration and programming was required because of the empirical nature of many of the parameters. Digital and analog solutions were considered before a modular analog system was selected. The VME mechanical standard was chosen mainly because of the high density backplane connectors and availability of shielded backplanes and flat cables, which provide easy and inexpensive signal routing to any module in the system. All inputs are single-ended. Low output noise levels permit daisy chaining of modules which allows implementation of complicated functions. All inputs and outputs are also accessible via miniature coaxial connectors on the front panel, together with polarity and range switches and ten turn precision potentiometers for constant factor selection. 3 figs.

  16. Optimization of removal function in computer controlled optical surfacing

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Guo, Peiji; Ren, Jianfeng

    2010-10-01

    The technical principle of computer controlled optical surfacing (CCOS) and the common method of optimizing removal function that is used in CCOS are introduced in this paper. A new optimizing method time-sharing synthesis of removal function is proposed to solve problems of the removal function being far away from Gaussian type and slow approaching of the removal function error that encountered in the mode of planet motion or translation-rotation. Detailed time-sharing synthesis of using six removal functions is discussed. For a given region on the workpiece, six positions are selected as the centers of the removal function; polishing tool controlled by the executive system of CCOS revolves around each centre to complete a cycle in proper order. The overall removal function obtained by the time-sharing process is the ratio of total material removal in six cycles to time duration of the six cycles, which depends on the arrangement and distribution of the six removal functions. Simulations on the synthesized overall removal functions under two different modes of motion, i.e., planet motion and translation-rotation are performed from which the optimized combination of tool parameters and distribution of time-sharing synthesis removal functions are obtained. The evaluation function when optimizing is determined by an approaching factor which is defined as the ratio of the material removal within the area of half of the polishing tool coverage from the polishing center to the total material removal within the full polishing tool coverage area. After optimization, it is found that the optimized removal function obtained by time-sharing synthesis is closer to the ideal Gaussian type removal function than those by the traditional methods. The time-sharing synthesis method of the removal function provides an efficient way to increase the convergence speed of the surface error in CCOS for the fabrication of aspheric optical surfaces, and to reduce the intermediate- and high

  17. Distributed computing environments for future space control systems

    NASA Technical Reports Server (NTRS)

    Viallefont, Pierre

    1993-01-01

    The aim of this paper is to present the results of a CNES research project on distributed computing systems. The purpose of this research was to study the impact of the use of new computer technologies in the design and development of future space applications. The first part of this study was a state-of-the-art review of distributed computing systems. One of the interesting ideas arising from this review is the concept of a 'virtual computer' allowing the distributed hardware architecture to be hidden from a software application. The 'virtual computer' can improve system performance by adapting the best architecture (addition of computers) to the software application without having to modify its source code. This concept can also decrease the cost and obsolescence of the hardware architecture. In order to verify the feasibility of the 'virtual computer' concept, a prototype representative of a distributed space application is being developed independently of the hardware architecture.

  18. Comparison of ultrasonography with submentovertex films and computed tomography scan in the diagnosis of zygomatic arch fractures

    PubMed Central

    Nezafati, S; Javadrashid, R; Rad, S; Akrami, S

    2010-01-01

    Objectives The aim of this study was to compare ultrasonography with CT scan and submentovertex films in the visualization of zygomatic arch fractures. Methods 17 patients, 10 men and 7 women, with suspected fracture of the zygomatic arch were studied. The data from CT and plain films were compared with the ultrasonographic findings (Aloka 3500 (Tokyo, Japan) ultrasound equipment with a 7.5 MHz transducer). The probe was situated over the fractured arch transversely to evaluate its whole length. All of the sonograms were taken and interpreted by the same sonologist, who was not aware of the results of the CT and the plain films. Results Ultrasound was accurate in assessing the fractured arches with sensitivity of 88.2% (15 of the 17 patients, with two false negatives) and specificity of 100% (no false positives). Conclusion Ultrasound is accurate in the visualization of zygomatic arch fractures and can be used as an adjunct to plain films to reduce the overall radiation exposure. PMID:20089738

  19. Uncertainty budget for a whole body counter in the scan geometry and computer simulation of the calibration phantoms.

    PubMed

    Schlagbauer, M; Hrnecek, E; Rollet, S; Fischer, H; Brandl, A; Kindl, P

    2007-01-01

    At the Austrian Research Centers Seibersdorf (ARCS), a whole body counter (WBC) in the scan geometry is used to perform routine measurements for the determination of radioactive intake of workers. The calibration of the WBC is made using bottle phantoms with a homogeneous activity distribution. The same calibration procedures have been simulated using Monte Carlo N-Particle (MCNP) code and FLUKA and the results of the full energy peak efficiencies for eight energies and five phantoms have been compared with the experimental results. The deviation between experiment and simulation results is within 10%. Furthermore, uncertainty budget evaluations have been performed to find out which parameters make substantial contributions to these differences. Therefore, statistical errors of the Monte Carlo simulation, uncertainties in the cross section tables and differences due to geometrical considerations have been taken into account. Comparisons between these results and the one with inhomogeneous distribution, for which the activity is concentrated only in certain parts of the body (such as head, lung, arms and legs), have been performed. The maximum deviation of 43% from the homogeneous case has been found when the activity is concentrated on the arms. PMID:17656442

  20. Efficient computer algebra algorithms for polynomial matrices in control design

    NASA Technical Reports Server (NTRS)

    Baras, J. S.; Macenany, D. C.; Munach, R.

    1989-01-01

    The theory of polynomial matrices plays a key role in the design and analysis of multi-input multi-output control and communications systems using frequency domain methods. Examples include coprime factorizations of transfer functions, cannonical realizations from matrix fraction descriptions, and the transfer function design of feedback compensators. Typically, such problems abstract in a natural way to the need to solve systems of Diophantine equations or systems of linear equations over polynomials. These and other problems involving polynomial matrices can in turn be reduced to polynomial matrix triangularization procedures, a result which is not surprising given the importance of matrix triangularization techniques in numerical linear algebra. Matrices with entries from a field and Gaussian elimination play a fundamental role in understanding the triangularization process. In the case of polynomial matrices, matrices with entries from a ring for which Gaussian elimination is not defined and triangularization is accomplished by what is quite properly called Euclidean elimination. Unfortunately, the numerical stability and sensitivity issues which accompany floating point approaches to Euclidean elimination are not very well understood. New algorithms are presented which circumvent entirely such numerical issues through the use of exact, symbolic methods in computer algebra. The use of such error-free algorithms guarantees that the results are accurate to within the precision of the model data--the best that can be hoped for. Care must be taken in the design of such algorithms due to the phenomenon of intermediate expressions swell.