WorldWideScience

Sample records for vxr-12 digitizer performances

  1. Evaluation of the vidar`s VXR-12 digitizer performances for film dosimetry of beams delimited by multileaf collimator

    Energy Technology Data Exchange (ETDEWEB)

    Julia, F. [Centre de Lutte Contre le Cancer Gustave-Roussy, 94 - Villejuif (France); Briot, E.

    1995-12-01

    The development of new irradiation techniques such as conformal radiotherapy increasingly implies the use of a multileaf collimator. The measurement of dose gradients in the penumbra region, and of dose distributions at the edge of complex shaped fields defined by multileaf collimators requires a high definition dosimetric method. Nowadays film digitizers have been notably improved and allow the film dosimetry to be faster, more accurate, presenting a sensitivity and high spatial resolution. To be able to perform the study of physical and dosimetric specifications of a multileaf collimator, we have evaluated the performances of the Vidar VCR-12 digitizer, with respect to its sensitivity, linearity, optical density range and the resolution. These performances were compared with the performances of different systems already in use in our department, either manual or automatic, using specific patterns. The main limitation for dosimetric use is the detection threshold that can introduce errors in isodose calculation, especially for the lowest values. The result of the intercomparisons have allowed corrections to be added, taking into account this Vidar problem. The results obtained after correction for the dose profiles of squared fields are in good agreement with ionization chamber measurements in a water phantom. It is concluded that Vidar digitizer is suitable for the use of film dosimetry for the dose distributions in fields defined by multileaf collimator.

  2. Performing Digital Literature

    Directory of Open Access Journals (Sweden)

    Jerome Fletcher

    2015-11-01

    Full Text Available Digital literature is a complex assemblage of related elements –material, spatial, linguistic, performative, textual, cultural, social– each of which is at one time interdependent and detached. This article discusses the literary creation within the cyberculture from the performativity point of view in relation to the textual apparatus. This is done through the analysis of a selection of performances where physical corporeality has a collaborative function with the body to a greater or lesser degree. Therefore, this physical feature can not only change, but stand at three possible and hybridizable axes: 1 the digital text as protagonist, 2 the digital text as counterpart, and 3 the digital text as site.

  3. Videogames as digital audiovisual performance

    OpenAIRE

    d'Escrivan, Julio

    2014-01-01

    Video games are an ideal medium for creating a live-cinema experience because of their potential for cinematic narrative and open structure. "Performing digital media' as opposed to 'performing with digital media' or using digital media in performance, means to play the media like a musical instrument as much as possible. This is to be able to control and finely nuance the audiovisual and kinetic data stream through live manipulation and interaction on stage. This is, in a sense, to grant the...

  4. Digital Troposcatter Performance Model

    Science.gov (United States)

    1983-12-01

    D,.-iD out ’e Pthr ~ These performance measures require a complete statistical de- scription of the components of the detection variable, which we...BER threshold Pthr " Let us denote by r the region of the 5-dimensional space (y,y) in which the BER exceeds Pthr : r = (Yy I): Pe(Y,!i) > Pthrl (A.46...y) by solving the nonlinear equation ... Pe ( Y,_21)= Pthr . A closed form expression for Pout(y) cannot be - obtained. Instead we developed an

  5. High Performance Proactive Digital Forensics

    Science.gov (United States)

    Alharbi, Soltan; Moa, Belaid; Weber-Jahnke, Jens; Traore, Issa

    2012-10-01

    With the increase in the number of digital crimes and in their sophistication, High Performance Computing (HPC) is becoming a must in Digital Forensics (DF). According to the FBI annual report, the size of data processed during the 2010 fiscal year reached 3,086 TB (compared to 2,334 TB in 2009) and the number of agencies that requested Regional Computer Forensics Laboratory assistance increasing from 689 in 2009 to 722 in 2010. Since most investigation tools are both I/O and CPU bound, the next-generation DF tools are required to be distributed and offer HPC capabilities. The need for HPC is even more evident in investigating crimes on clouds or when proactive DF analysis and on-site investigation, requiring semi-real time processing, are performed. Although overcoming the performance challenge is a major goal in DF, as far as we know, there is almost no research on HPC-DF except for few papers. As such, in this work, we extend our work on the need of a proactive system and present a high performance automated proactive digital forensic system. The most expensive phase of the system, namely proactive analysis and detection, uses a parallel extension of the iterative z algorithm. It also implements new parallel information-based outlier detection algorithms to proactively and forensically handle suspicious activities. To analyse a large number of targets and events and continuously do so (to capture the dynamics of the system), we rely on a multi-resolution approach to explore the digital forensic space. Data set from the Honeynet Forensic Challenge in 2001 is used to evaluate the system from DF and HPC perspectives.

  6. Performance results for digital subscriber line precoders

    NARCIS (Netherlands)

    Whiting, P.A.; Ashikhmin, A.; Borst, S.C.; Jennen, J.; Kramer, G.; Lind van Wijngaarden, A.J.; Zivkovic, M.

    2008-01-01

    Performance results are presented for digital subscriber line (DSL) precoders, also known as dynamic spectrum management (DSM) level 3, in terms of improvement of signal-to-noise ratio (SNR) and achievable bit rates under the very high speed digital subscriber line 2 (VDSL2) standard. Simulations we

  7. From Page to Digital Stage: Creating Digital Performances of Poetry

    Science.gov (United States)

    Hughes, Janette; John, Amy

    2009-01-01

    The authors share the story of a performance-based poetry project undertaken by a class of grade 6 and 7 students. The use of new digital media for reading, writing, and representing poetry encouraged an exploration of the relationship between text and image and how images and sound might be used to mediate meaning making. New media have an…

  8. Digital breast tomosynthesis versus digital mammography: a clinical performance study

    Energy Technology Data Exchange (ETDEWEB)

    Gennaro, Gisella; Baldan, Enrica; Bezzon, Elisabetta; Polico, Ilaria; Proietti, Alessandro; Toffoli, Aida [Venetian Oncological Institute (IOV), IRCCS, Department of Radiology, Padua (Italy); Toledano, Alicia [Statistics Collaborative Inc., Washington, DC (United States); Di Maggio, Cosimo [Padua University, Department of Oncological and Surgical Sciences, Padua (Italy); La Grassa, Manuela [Aviano Oncological Reference Center (CRO), IRCCS, Department of Radiology, Aviano (Pordenone) (Italy); Pescarini, Luigi [Venetian Oncological Institute (IOV), IRCCS, Department of Radiology, Padua (Italy); Padua University, Department of Oncological and Surgical Sciences, Padua (Italy); Muzzio, Pier Carlo [Venetian Oncological Institute (IOV), IRCCS, Department of Radiology, Padua (Italy); Padua University, Department of Medical Diagnostic Sciences, Padua (Italy)

    2010-07-15

    To compare the clinical performance of digital breast tomosynthesis (DBT) with that of full-field digital mammography (FFDM) in a diagnostic population. The study enrolled 200 consenting women who had at least one breast lesion discovered by mammography and/or ultrasound classified as doubtful or suspicious or probably malignant. They underwent tomosynthesis in one view [mediolateral oblique (MLO)] of both breasts at a dose comparable to that of standard screen-film mammography in two views [craniocaudal (CC) and MLO]. Images were rated by six breast radiologists using the BIRADS score. Ratings were compared with the truth established according to the standard of care and a multiple-reader multiple-case (MRMC) receiver-operating characteristic (ROC) analysis was performed. Clinical performance of DBT compared with that of FFDM was evaluated in terms of the difference between areas under ROC curves (AUCs) for BIRADS scores. Overall clinical performance with DBT and FFDM for malignant versus all other cases was not significantly different (AUCs 0.851 vs 0.836, p = 0.645). The lower limit of the 95% CI or the difference between DBT and FFDM AUCs was -4.9%. Clinical performance of tomosynthesis in one view at the same total dose as standard screen-film mammography is not inferior to digital mammography in two views. (orig.)

  9. How to perform digital removal of faeces.

    Science.gov (United States)

    Peate, Ian

    2016-06-01

    Rationale and key points This article provides practitioners with information about how to perform digital removal of faeces in a safe, effective and patient-centred manner, promoting privacy and dignity. Passing faecal matter is essential to enable the elimination of waste. For some people, however, defecation is not possible without some form of intervention; this could be the administration of oral medication or an enema, insertion of suppositories or digital removal of faeces. ▶ Bowel care is a fundamental aspect of patient care. ▶ Digital removal of faeces should be performed by a practitioner competent in this skill. ▶ Digital removal of faeces is an invasive procedure and should only be carried out when necessary following holistic patient assessment. Reflective activity Clinical skills articles can help update your practice and ensure it remains evidence based. Apply this article to your practice. Reflect on and write a short account of: 1. How you think this article will improve your practice. 2. How the patient receiving the care you delivered might have felt. Subscribers can upload their reflective accounts at: rcni.com/portfolio .

  10. Why is digit ratio correlated to sports performance?

    Science.gov (United States)

    Kim, Tae Beom; Kim, Khae Hawn

    2016-01-01

    Second to fourth digit ratio is the ratio of second to fourth digit length. It has been known that digit ratio is sexually dimorphic in humans, such that males tend to have lower digit ratio (longer fourth digits relative to second digits) than females. Digit ratio is thought to be a biomarker of the balance between fetal testosterone (FT) and fetal estrogen (FE) in a relatively narrow developmental window at the end of the first trimester of pregnancy. On the contrary, the relationships between digit ratio and levels of sex steroids in adults are not clear. Most correlational studies between digit ratio and adult sex steroids have revealed that this association is statistically not significant. However, for many years, a lot of researches showed negative relationships between digit ratio and sports performance such as rugby, surfing, rowing, sprinting, endurance, and hand grip strength. Here, we discuss possible mechanisms about the relationships between digit ratio and sports performance. PMID:28119871

  11. Library performance measurement in the digital age

    OpenAIRE

    Conyers, A.; Payne, Philip

    2011-01-01

    Book synopsis: University libraries around the world have embraced the possibilities of the digital learning environment, facilitating its use and proactively seeking to develop the provision of electronic resources and services. The digital environment offers opportunities and challenges for librarians in all aspects of their work - in information literacy, virtual reference, institutional repositories, e-learning, managing digital resources and social media. The authors in this timely book ...

  12. Digital Image Correlation for Performance Monitoring.

    Energy Technology Data Exchange (ETDEWEB)

    Palaviccini, Miguel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Turner, Daniel Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Herzberg, Michael [National Security Campus, Kansas City, MO (United States)

    2016-02-01

    Evaluating the health of a mechanism requires more than just a binary evaluation of whether an operation was completed. It requires analyzing more comprehensive, full-field data. Health monitoring is a process of nondestructively identifying characteristics that indicate the fitness of an engineered component. In order to monitor unit health in a production setting, an automated test system must be created to capture the motion of mechanism parts in a real-time and non-intrusive manner. One way to accomplish this is by using high-speed video (HSV) and Digital Image Correlation (DIC). In this approach, individual frames of the video are analyzed to track the motion of mechanism components. The derived performance metrics allow for state-of-health monitoring and improved fidelity of mechanism modeling. The results are in-situ state-of-health identification and performance prediction. This paper introduces basic concepts of this test method, and discusses two main themes: the use of laser marking to add fiducial patterns to mechanism components, and new software developed to track objects with complex shapes, even as they move behind obstructions. Finally, the implementation of these tests into an automated tester is discussed.

  13. High-performance digital color video camera

    Science.gov (United States)

    Parulski, Kenneth A.; D'Luna, Lionel J.; Benamati, Brian L.; Shelley, Paul R.

    1992-01-01

    Typical one-chip color cameras use analog video processing circuits. An improved digital camera architecture has been developed using a dual-slope A/D conversion technique and two full-custom CMOS digital video processing integrated circuits, the color filter array (CFA) processor and the RGB postprocessor. The system used a 768 X 484 active element interline transfer CCD with a new field-staggered 3G color filter pattern and a lenslet overlay, which doubles the sensitivity of the camera. The industrial-quality digital camera design offers improved image quality, reliability, manufacturability, while meeting aggressive size, power, and cost constraints. The CFA processor digital VLSI chip includes color filter interpolation processing, an optical black clamp, defect correction, white balance, and gain control. The RGB postprocessor digital integrated circuit includes a color correction matrix, gamma correction, 2D edge enhancement, and circuits to control the black balance, lens aperture, and focus.

  14. Performance Analysis of Digital loudspeaker Arrays

    DEFF Research Database (Denmark)

    Pedersen, Bo Rohde; Kontomichos, Fotios; Mourjopoulos, John

    2008-01-01

    An analysis of digital loudspeaker arrays shows that the ways in which bits are mapped to the drivers influence the quality of the audio result. Specifically, a "bit-summed" rather than the traditional "bit-mapped" strategy greatly reduces the number of times drivers make binary transitions per...... period of the input frequency. Detailed simulations compare the results for a 32-loudspeaker array with a similar configuration with analog excitation of the drivers. Ideally, drivers in digital arrays should be very small and span a small area, but that sets limits on the low-frequency response...

  15. Performance Analysis of Digital loudspeaker Arrays

    DEFF Research Database (Denmark)

    Pedersen, Bo Rohde; Kontomichos, Fotios; Mourjopoulos, John

    2008-01-01

    An analysis of digital loudspeaker arrays shows that the ways in which bits are mapped to the drivers influence the quality of the audio result. Specifically, a "bit-summed" rather than the traditional "bit-mapped" strategy greatly reduces the number of times drivers make binary transitions per p...

  16. Digital Technologies and performative pedagogies: Repositioning the visual

    OpenAIRE

    Kathryn Grushka; Debra Donnelly

    2010-01-01

    Images are becoming a primary means of information presentation in the digitized global media and digital technologies have emancipated and democratized the image. This allows for the reproduction and manipulation of images on a scale never seen before and opens new possibilities for teachers schooled in critical visuality. This paper reports on an innovative pre-service teacher training course in which a cross-curricula cohort of secondary teachers employed visual performative competencies t...

  17. The Digital Divide and Its Impact on Academic Performance

    Science.gov (United States)

    Sun, Jerry Chih-Yuan; Metros, Susan E.

    2011-01-01

    The purpose of this article is to explore issues of the digital divide and its impact on academic performance. Research shows that proper use of technology by students increases their academic performance outcomes. In the literature review section, the authors review articles and theories based on Bennett's (2001) societal equity framework. The…

  18. Performance Comparison of Hybrid Signed Digit Arithmetic in Efficient Computing

    Directory of Open Access Journals (Sweden)

    VISHAL AWASTHI

    2011-10-01

    Full Text Available In redundant representations, addition can be carried out in a constant time independent of the word length of the operands. Adder forms a fundamental building block in almost majority of VLSI designs. A hybrid adder can add an unsigned number to a signed-digit number and hence their efficient performance greatly determinesthe quality of the final output of the concerned circuit. In this paper we designed and compared the speed of adders by reducing the carry propagation time with the help of combined effect of improved architectures of adders and signed digit representation of number systems. The key idea is to draw out a compromise between execution time of fast adding process and area available which is often very limited. In this paper we also tried to verify the various algorithms of signed digit and hybrid signed digit adders.

  19. A digital CDS technique and the performance testing

    CERN Document Server

    Liu, Xiao-Yan; Yang, Yan-Ji; Lu, Bo; Wang, Yu-Sa; Xu, Yu-Peng; Cui, Wei-Wei; Li, Wei; Li, Mao-Shun; Wang, Juan; Han, Da-Wei; Chen, Tian-Xiang; Huo, Jia; Hu, Wei; Zhang, Yi; Zhu, Yue; Zhang, Zi-Liang; Yin, Guo-He; Wang, Yu; Zhao, Zhong-Yi; Fu, Yan-Hong; Zhang, Ya; Ma, Ke-Yan; Chen, Yong

    2014-01-01

    Readout noise is a critical parameter for characterizing the performance of charge-coupled devices (CCDs), which can be greatly reduced by the correlated double sampling (CDS) circuit. However, conventional CDS circuit inevitably introduces new noises since it consists of several active analog components such as operational amplifiers. This paper proposes a digital CDS circuit technique, which transforms the pre-amplified CCD signal into a train of digital presentations by a high-speed data acquisition card directly without the noisy CDS circuit first, then implement the digital CDS algorithm through numerical method. The readout noise of 3.3 e$^{-}$ and the energy resolution of 121 eV@5.9keV can be achieved via the digital CDS technique.

  20. Performance Indicators for the Digital Library

    OpenAIRE

    2001-01-01

    The purpose of performance indicators is „to assess the quality and effectiveness of services provided by a library ... and to assess the efficiency of resources allocated by the library to such services.” In the last decades, libraries have developed sets of performance indicators for evaluating the quality of their services. Such indicators have been presented in handbooks and in an international standard. They were for the most part restricted to the traditional library services (collectio...

  1. Comparing the performance of three digital forensic tools

    Directory of Open Access Journals (Sweden)

    Brian Cusack

    Full Text Available Software used for digital forensic investigations requires to be verified against reliability and validity criteria. In this paper, three well known tools are tested against the mandatory features of digital forensic tools published by the National Institute of Standards (NIST. It was found that a variation in performance existed between the tools, with all having measureable areas of non performance. The findings have an impact on the professional use of the tools and illustrate the need for benchmarking and testing of the tools before use.

  2. Performance Indicators for the Digital Library

    Directory of Open Access Journals (Sweden)

    Roswitha Poll

    2001-07-01

    Full Text Available The purpose of performance indicators is „to assess the quality and effectiveness of services provided by a library ... and to assess the efficiency of resources allocated by the library to such services.” In the last decades, libraries have developed sets of performance indicators for evaluating the quality of their services. Such indicators have been presented in handbooks and in an international standard. They were for the most part restricted to the traditional library services (collection, lending and ILL services, reading rooms, reference desk. For the fast developing electronic library services new and special indicators are needed in order to assess the effectiveness of services and to justify expenditure and resource allocation to that sector. In several projects on a national and international scale, such indicators have been developed and tested.

  3. The place for performance in the digital holographic space

    Science.gov (United States)

    Azevedo, Isabel; Richardson, Martin; Sandford-Richardson, Elizabeth; Bernardo, Luis Miguel; Crespo, Helder

    2014-02-01

    In this series of digital art holograms and lenticulars, we are examining different kinds of movement inside the digital holographic space explored by Elizabeth Sandford-Richardson, a visual performance artist. During the process of capturing the image, we used the HoloCam Portable Light System, equipped with Canon and Nikon cameras positioned at different heights and angles, in order to improve the rendering of the holographic space. Based on the "Performativity of Performance Documentation" a notion introduced by Philip Auslanderi we revisit some authors that have been working in the "theatrical" practise, mainly in photography, adding the possibility of movement in 3D space. We must realise that the movement of the viewer in front of a digital holographic image creates the performance that he/she is looking at. We should consider the physical space, outside the hologram, and this kind of "performance acts", also part of the work. In summary, we propose a reflection on the digital holographic space, time, movement and its place in contemporary art.

  4. Design and performance analysis of digital acoustic underwater telemetry system

    Science.gov (United States)

    Catipovic, J. A.; Baggeroer, A. B.; Vonderheydt, K.; Koelsch, D. E.

    1985-11-01

    The work discusses the design and performance characteristics of a Digital Acoustic Telemetry System (DATS) which incorporates the current state-of-the-art technology and is capable of reliable data transmission at rates useful to a wide range of ocean exploration and development gear.

  5. Digital Technologies and performative pedagogies: Repositioning the visual

    Directory of Open Access Journals (Sweden)

    Kathryn Grushka

    2010-05-01

    Full Text Available Images are becoming a primary means of information presentation in the digitized global media and digital technologies have emancipated and democratized the image. This allows for the reproduction and manipulation of images on a scale never seen before and opens new possibilities for teachers schooled in critical visuality. This paper reports on an innovative pre-service teacher training course in which a cross-curricula cohort of secondary teachers employed visual performative competencies to produce a series of learning objects on a digital platform. The resulting intertextual narratives demonstrate that the manipulation of image and text offered by digital technologies create a powerful vehicle for investigating knowledge and understandings, evolving new meaning and awakening latent creativity in the use of images for meaning making. This research informs the New Literacies and multimodal fields of enquiry and argues that visuality is integral to any pedagogy that purports to be relevant to the contemporary learner. It argues that the visual has been significantly under-valued as a conduit for knowledge acquisition and meaning making in the digital environment and supports the claim that critical literacy, interactivity, experimentation and production are vital to attaining the tenets of transformative education (Buckingham, 2007; Walsh, 2007; Cope & Kalantzis, 2008.

  6. Listening to Mozart does not enhance backwards digit span performance.

    Science.gov (United States)

    Steele, K M; Ball, T N; Runk, R

    1997-06-01

    Rauscher, Shaw, and Ky recently reported that exposure to brief periods of music by Mozart produced a temporary increase in performance on tasks taken from the Stanford-Binet Intelligence Scale-IV. The present study examined whether this effect occurred in performance on a backwards digit span task. In a within-subjects design 36 undergraduates were exposed to 10-min. periods of Mozart music, a recording of rain, or silence. After each stimulus period, undergraduates had three attempts to hear and recall different 9-digit strings in reverse order. No significant differences among treatment conditions were found. There was a significant effect of practice. Results are discussed in terms of the need to isolate the conditions responsible for production of the Mozart effect.

  7. Monobit Digital Receivers for QPSK: Design, Analysis and Performance

    CERN Document Server

    Wang, Zhiyong; Zhang, Wenyi; Wei, Guo

    2012-01-01

    Future communication system requires large bandwidth to achieve high data rate up to multigigabit/ sec, which makes analog-to-digital (ADC) become a key bottleneck for the implementation of digital receivers due to its high complexity and large power consumption. Therefore, monobit receivers for BPSK have been proposed to address this problem. In this work, QPSK modulation is considered for higher data rate. First, the optimal receiver based on monobit ADC with Nyquist sampling is derived, and its corresponding performance in the form of deflection ratio is calculated. Then a suboptimal but more practical monobit receiver is obtained, along with iterative demodulation and small sample removal. The effect of the imbalances between the In-phase (I) and Quadrature-phase (Q) branches, including the amplitude and phase imbalances, is carefully investigated too. To combat the performance loss caused by IQ imbalances, monobit receivers based on double training sequences are proposed. Numerical simulations show that ...

  8. Performance evaluation of macro lens in digital close range photogrammetry

    Science.gov (United States)

    Yanagi, H.; Chikatsu, H.

    2009-08-01

    Recently, the documentation and visualization of various cultural heritages have been receiving attention, and a small Buddha such as less than 10 cm tall which was stored in the womb of Buddha is also included in cultural heritages. Zoom lenses are generally used to document these small objects and thus conserve the cultural heritage. However, there exist certain issues pertaining to the use of zoom lenses for such digital documentation. These issues include image sharpness and distortions that occur with changes in focal length setting, and in particular, the depth of field is issue from application standpoint such as documentation of the small cultural heritage. On the other hand, macro lenses can be used to capture sharp images of small objects from the view point of working distance, and its depth of field is related to the aperture of the camera. In order to evaluate the effectiveness of macro lenses in digital close range photogrammetry, macro lens and zoom lens were mounted on a digital single lens reflex camera (Canon EOS20D, 8.2 Mega pixels). This paper deals in a first part with comparative evaluations for both lenses with respect to their lens distortion, imaging mode, and calibration aspects. The results indicated that macro lenses were more suitable for digital close range photogrammetry. Calibration tests are performed to demonstrate the effectiveness and practicability of macro lens in close range photogrammetic applications.

  9. The Sloan Digital Sky Survey Telescope Performance Monitor

    Science.gov (United States)

    McGehee, Peregrine M.; Brinkmann, Jon; Rockosi, Constance M.; Long, Dan; Snedden, Stephanie A.; Kleinman, S. J.; Nitta, Atsuko; Harvanek, Michael; Newman, Peter R.; Neilsen, Eric H., Jr.; Krzesinski, Jurek

    2002-12-01

    The Telescope Performance Monitor (TPM) installed at the Sloan Digital Sky Survey (SDSS) located at Apache Point Observatory provides access to real-time and archived engineering data. The modularity present in the underlying Experimental Physics and Industrial Control System (EPICS) toolkit allows the observers and operations staff to develop their own approaches to data access and analysis. These techniques are summarized and the use of the TPM to solve critical project issues including analysis and correction of thermal management problems are presented.

  10. Measurements for the Performance of the Digital Autocorrelation Spectrometer

    Institute of Scientific and Technical Information of China (English)

    Fa-Chun Lu; Jarken Esimbek; Jian-Jun Zhou; Xing-Wu Zheng

    2007-01-01

    Injecting phase calibration (PCAL) signals to the feed horn of the observation system and analyzing the output response signals of the spectrometer, we measured the working performance of a 4096-channel digital autocalibration spectrometer. The results demonstrate that the spectrometer has a fine working performance: (1) the channels are distributed uniformly in the spectrometer; (2) line drift produces little effect on the observation results; (3)spectral resolution shows little changes with observation time. The distribution of the frequency resolution in an 80 MHz bandwidth was measured. A trial observation on the two molecular spectral lines of H2CO and H 110α taken with this spectrometer is described.

  11. El cuerpo-huella en el performance digital 10 minutos

    Directory of Open Access Journals (Sweden)

    Daniel Enrique Ariza Gómez, PhD

    2017-01-01

    Full Text Available Este artículo de reflexión aborda el concepto de cuerpo-huella, eje principal del performance “El fajadito”. Esta puesta en escena forma parte de una creación escénica más grande llamada 10 minutos, performance digital que pone en tensión la relación cuerpo-máquina en el entorno de una unidad de cuidados intensivos (UCI, y se entrelaza junto con otros tres para ofrecer al público la totalidad de una obra que surge del proceso de investigación-creación 10 minutos. El discurso del presente artículo se abrirá hacia la comprensión de la manera en que fue abordado, para el performance “El fajadito”, el cuerpo de las personas víctimas de minas antipersona en Colombia. Un cuerpo-huella que aparece en la puesta en escena como un cuerpo en suspensión proponiendo con ello una postura política y social sobre lo que ha significado, para Colombia, el uso de armas que no buscan la muerte del individuo, sino la provocación del dolor y exhibe un cuerpo mutilado como huella de guerra. Palabras clave: fajaditos, cuerpo-huella, 10 minutos, performance digital, minas antipersona.

  12. Simultaneous Transmit and Receive Performance of an 8-channel Digital Phased Array

    Science.gov (United States)

    2017-01-16

    Simultaneous Transmit and Receive Performance of an 8- channel Digital Phased Array Jonathan P. Doane, Kenneth E. Kolodziej, Bradley T. Perry MIT...traditional digital cancellation is typically limited by channel noise and distortion. A unique aspect of the ALSTAR digital canceller is the use of...elements, and an 8- channel digital transceiver chassis. width which is mixed to an IF center frequency of 187.5 MHz, supporting digital sampling in the

  13. Volumetric breast density affects performance of digital screening mammography.

    Science.gov (United States)

    Wanders, Johanna O P; Holland, Katharina; Veldhuis, Wouter B; Mann, Ritse M; Pijnappel, Ruud M; Peeters, Petra H M; van Gils, Carla H; Karssemeijer, Nico

    2017-02-01

    To determine to what extent automatically measured volumetric mammographic density influences screening performance when using digital mammography (DM). We collected a consecutive series of 111,898 DM examinations (2003-2011) from one screening unit of the Dutch biennial screening program (age 50-75 years). Volumetric mammographic density was automatically assessed using Volpara. We determined screening performance measures for four density categories comparable to the American College of Radiology (ACR) breast density categories. Of all the examinations, 21.6% were categorized as density category 1 ('almost entirely fatty') and 41.5, 28.9, and 8.0% as category 2-4 ('extremely dense'), respectively. We identified 667 screen-detected and 234 interval cancers. Interval cancer rates were 0.7, 1.9, 2.9, and 4.4‰ and false positive rates were 11.2, 15.1, 18.2, and 23.8‰ for categories 1-4, respectively (both p-trend density categories: 85.7, 77.6, 69.5, and 61.0% for categories 1-4, respectively (p-trend density, automatically measured on digital mammograms, impacts screening performance measures along the same patterns as established with ACR breast density categories. Since measuring breast density fully automatically has much higher reproducibility than visual assessment, this automatic method could help with implementing density-based supplemental screening.

  14. Performance evaluation of the time delay digital tanlock loop architectures

    Science.gov (United States)

    Al-Kharji Al-Ali, Omar; Anani, Nader; Al-Qutayri, Mahmoud; Al-Araji, Saleh; Ponnapalli, Prasad

    2016-01-01

    This article presents the architectures, theoretical analyses and testing results of modified time delay digital tanlock loop (TDTLs) system. The modifications to the original TDTL architecture were introduced to overcome some of the limitations of the original TDTL and to enhance the overall performance of the particular systems. The limitations addressed in this article include the non-linearity of the phase detector, the restricted width of the locking range and the overall system acquisition speed. Each of the modified architectures was tested by subjecting the system to sudden positive and negative frequency steps and comparing its response with that of the original TDTL. In addition, the performance of all the architectures was evaluated under noise-free as well as noisy environments. The extensive simulation results using MATLAB/SIMULINK demonstrate that the new architectures overcome the limitations they addressed and the overall results confirmed significant improvements in performance compared to the conventional TDTL system.

  15. Effects of Stereoscopic 3D Digital Radar Displays on Air Traffic Controller Performance

    Science.gov (United States)

    2013-03-01

    Effects of Stereoscopic 3D Digital Radar Displays on Air Traffic Controller Performance THESIS...and is not subject to copyright protection in the United States. AFIT-ENV-13-M-24 Effects of Stereoscopic 3D Digital Radar Displays on Air... Stereoscopic 3D Digital Radar Displays on Air Traffic Controller Performance Jason G. Russi Technical Sergeant, USAF Approved

  16. Influence of discretization method on the digital control system performance

    Directory of Open Access Journals (Sweden)

    Futás József

    2003-12-01

    Full Text Available The design of control system can be divided into two steps. First the process or plant have to be convert into mathematical model form, so that its behavior can be analyzed. Then an appropriate controller have to be design in order to get the desired response of the controlled system. In the continuous time domain the system is represented by differential equations. Replacing a continuous system into discrete time form is always an approximation of the continuous system. The different discretization methods give different digital controller performance. The methods presented on the paper are Step Invariant or Zero Order Hold (ZOH Method, Matched Pole-Zero Method, Backward difference Method and Bilinear transformation. The above mentioned discretization methods are used in developing PI position controller of a dc motor. The motor model was converted by the ZOH method. The performances of the different methods are compared and the results are presented.

  17. Contemporary performativities and the imperative of participation in digital technologies

    Directory of Open Access Journals (Sweden)

    Gisela Cánepa Koch

    2015-01-01

    Full Text Available In a processual perspective of social life, technology works within discursive and action frames that make it possible. these frames provide meaning and legitimate technology but are also produced through technology and its uses. In other words, actions frames of an era are constitutive of and constituted by technology. this perspective follows a performative approach on digital technologies which allow the authors to problematize them in terms of their actors, discourses, and practices. On this way, the authors go beyond views that tend to dichotomize in order to understand issues of representation and power relations. Yet, what happens when actor’s performances and the performative force of their practices are no longer an aspect of their dynamics and configuration, but rather a normative force? In other words, what is at stake when actors and their performances are organized by performance as a mandate, that is, as a regime of truth? In a context where the principles of efficiency, effectiveness and efficacy are a mandate, there is a need to ask this sort of question, particularly in relation to the paradoxes it poses to participatory regimes that respond to the demands of neoliberal governmentality.

  18. Measuring Digital PCR Quality: Performance Parameters and Their Optimization.

    Science.gov (United States)

    Lievens, A; Jacchia, S; Kagkli, D; Savini, C; Querci, M

    2016-01-01

    Digital PCR is rapidly being adopted in the field of DNA-based food analysis. The direct, absolute quantification it offers makes it an attractive technology for routine analysis of food and feed samples for their composition, possible GMO content, and compliance with labelling requirements. However, assessing the performance of dPCR assays is not yet well established. This article introduces three straightforward parameters based on statistical principles that allow users to evaluate if their assays are robust. In addition, we present post-run evaluation criteria to check if quantification was accurate. Finally, we evaluate the usefulness of Poisson confidence intervals and present an alternative strategy to better capture the variability in the analytical chain.

  19. Measuring Digital PCR Quality: Performance Parameters and Their Optimization.

    Directory of Open Access Journals (Sweden)

    A Lievens

    Full Text Available Digital PCR is rapidly being adopted in the field of DNA-based food analysis. The direct, absolute quantification it offers makes it an attractive technology for routine analysis of food and feed samples for their composition, possible GMO content, and compliance with labelling requirements. However, assessing the performance of dPCR assays is not yet well established. This article introduces three straightforward parameters based on statistical principles that allow users to evaluate if their assays are robust. In addition, we present post-run evaluation criteria to check if quantification was accurate. Finally, we evaluate the usefulness of Poisson confidence intervals and present an alternative strategy to better capture the variability in the analytical chain.

  20. A comparison of the performance of digital mammography systems.

    Science.gov (United States)

    Monnin, P; Gutierrez, D; Bulling, S; Guntern, D; Verdun, F R

    2007-03-01

    An objective analysis of image quality parameters was performed for six digital mammography systems. The presampled modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) for the systems were determined at different doses, for 28 kVp with a Mo/Mo or W/Al target/filter combination and 2 mm of additional aluminium filtration. The flat-panel units have higher MTF and DQE in the mid to high frequency range than standard CR systems. The highest DQE, over the whole dose range, is for the slit-scanning direct photon counting system. Dual-side read CR can overcome the inherent x-ray absorption and signal collection limitations of standard CR mammography, improving the low-frequency DQE by 40%, to the same level as full-field systems, but it does not improve the poor spatial resolution of phosphor.

  1. Adaptive digital access protocol: new features and performance improvements

    Science.gov (United States)

    Doshi, B. T.; Dravida, S.; Kustka, G. J.; Magill, Peter D.; Siller, Curtis A., Jr.; Kotikalapudi, Sriram

    1996-11-01

    This paper reports on a broadband multiple access protocol for bi-directional hybrid fiber-coax (HFC) networks. Referred to here as the enhanced adaptive digital access protocol (ADAPt+TM), it builds upon earlier work to define a medium access control (MAC) protocol amenable to a multiple service environment supporting subscriber access in HFC networks with tree and branch topologies. ADAPt+ efficiently supports different access modes such as synchronous transfer mode (STM), asynchronous transfer mode (ATM), and variable length (VL) native data (e.g., IP, IPX). This enhanced protocol adapts to changing demands for a mix of circuit- and packet-mode applications, and efficiently allocates upstream and downstream bandwidth to isochronous and bursty traffic sources. This paper describes: ADAPt+ for upstream communication and multiplexing/demultiplexing for downstream communication; its applicability to STM, ATM and other native data applications; and performance attributes such as bandwidth efficiency and latency.

  2. Lower Bounds on the Performance of Analog to Digital Converters

    CERN Document Server

    Osqui, Mitra; Roozbehani, Mardavij

    2012-01-01

    This paper deals with the task of finding certified lower bounds for the performance of Analog to Digital Converters (ADCs). A general ADC is modeled as a causal, discrete-time dynamical system with outputs taking values in a finite set. We define the performance of an ADC as the worst-case average intensity of the filtered input matching error, defined as the difference between the input and output of the ADC. The passband of the shaping filter used to filter the error signal determines the frequency region of interest for minimizing the error. The problem of finding a lower bound for the performance of an ADC is formulated as a dynamic game problem in which the input signal to the ADC plays against the output of the ADC. Furthermore, the performance measure must be optimized in the presence of quantized disturbances (output of the ADC) that can exceed the control variable (input of the ADC) in magnitude. We characterize the optimal solution in terms of a Bellman-type inequality. A numerical approach is pres...

  3. High-Performance DA-Converters Application to Digital Transceivers

    CERN Document Server

    Clara, Martin

    2013-01-01

    This book deals with modeling and implementation of high performance, current-steering D/A-converters for digital transceivers in nanometer CMOS technology. In the first part, the fundamental performance limitations of current-steering DACs are discussed. Based on simplified models, closed-form expressions for a number of basic non-ideal effects are derived and tested.  With the knowledge of basic performance limits, the converter and system architecture can be optimized in an early design phase, trading off circuit complexity, silicon area and power dissipation for static and dynamic performance. The second part describes four different current-steering DAC designs in standard 130 nm CMOS. The converters have a resolution in the range of 12-14 bits for an analog bandwidth between 2.2 MHz and 50 MHz and sampling rates from 100 MHz to 350 MHz. Dynamic-Element-Matching (DEM) and advanced dynamic current calibration techniques are employed to minimize the required silicon area.

  4. High-performance VGA-resolution digital color CMOS imager

    Science.gov (United States)

    Agwani, Suhail; Domer, Steve; Rubacha, Ray; Stanley, Scott

    1999-04-01

    This paper discusses the performance of a new VGA resolution color CMOS imager developed by Motorola on a 0.5micrometers /3.3V CMOS process. This fully integrated, high performance imager has on chip timing, control, and analog signal processing chain for digital imaging applications. The picture elements are based on 7.8micrometers active CMOS pixels that use pinned photodiodes for higher quantum efficiency and low noise performance. The image processing engine includes a bank of programmable gain amplifiers, line rate clamping for dark offset removal, real time auto white balancing, per column gain and offset calibration, and a 10 bit pipelined RSD analog to digital converter with a programmable input range. Post ADC signal processing includes features such as bad pixel replacement based on user defined thresholds levels, 10 to 8 bit companding and 5 tap FIR filtering. The sensor can be programmed via a standard I2C interface that runs on 3.3V clocks. Programmable features include variable frame rates using a constant frequency master clock, electronic exposure control, continuous or single frame capture, progressive or interlace scanning modes. Each pixel is individually addressable allowing region of interest imaging and image subsampling. The sensor operates with master clock frequencies of up to 13.5MHz resulting in 30FPS. A total programmable gain of 27dB is available. The sensor power dissipation is 400mW at full speed of operation. The low noise design yields a measured 'system on a chip' dynamic range of 50dB thus giving over 8 true bits of resolution. Extremely high conversion gain result in an excellent peak sensitivity of 22V/(mu) J/cm2 or 3.3V/lux-sec. This monolithic image capture and processing engine represent a compete imaging solution making it a true 'camera on a chip'. Yet in its operation it remains extremely easy to use requiring only one clock and a 3.3V power supply. Given the available features and performance levels, this sensor will be

  5. Performance analysis of a digital capacitance measuring circuit.

    Science.gov (United States)

    Xu, Lijun; Sun, Shijie; Cao, Zhang; Yang, Wuqiang

    2015-05-01

    This paper presents the design and study of a digital capacitance measuring circuit with theoretical analysis, numerical simulation, and experimental evaluation. The static and dynamic performances of the capacitance measuring circuit are first defined, including signal-to-noise ratio (SNR), standard deviation, accuracy, linearity, sensitivity, and response time, within a given measurement range. Then numerical simulation is carried out to analyze the SNR and standard deviation of the circuit, followed by experiments to validate the overall performance of the circuit. The simulation results show that when the standard deviation of noise is 0.08 mV and the measured capacitance decreases from 6 pF to 3 fF, the SNR decreases from 90 dB to 22 dB and the standard deviation is between 0.17 fF and 0.24 fF. The experimental results show that when the measured capacitance decreases from 6 pF to 40 fF and the data sampled in a single period are used for demodulation, the SNR decreases from 88 dB to 40 dB and the standard deviation is between 0.18 fF and 0.25 fF. The maximum absolute error and relative error are 5.12 fF and 1.26%, respectively. The SNR and standard deviation can be further improved if the data sampled in more than one period are used for demodulation by the circuit.

  6. Digital passages. Moroccan-Dutch youths performing diaspora, gender and youth cultural identities across digital space

    NARCIS (Netherlands)

    Leurs, K.H.A.

    2012-01-01

    Digital Passages considers how the relations between gender, diaspora and youth culture are digitally articulated by Moroccan-Dutch youths between the age of 12 and 18 years old. Combining new media, gender and postcolonial theory, a transdisciplinary analysis is carried out of a young ethnic-minori

  7. Digital passages. Moroccan-Dutch youths performing diaspora, gender and youth cultural identities across digital space

    NARCIS (Netherlands)

    Leurs, K.H.A.|info:eu-repo/dai/nl/343295334

    2012-01-01

    Digital Passages considers how the relations between gender, diaspora and youth culture are digitally articulated by Moroccan-Dutch youths between the age of 12 and 18 years old. Combining new media, gender and postcolonial theory, a transdisciplinary analysis is carried out of a young ethnic-minori

  8. High Performance Low Cost Digitally Controlled Power Conversion Technology

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes

    2008-01-01

    Digital control of switch-mode power supplies and converters has within the last decade evolved from being an academic subject to an emerging market in the power electronics industry. This development has been pushed mainly by the computer industry that is looking towards digital power management...

  9. Analysis of Performance and Designing of Bi-Quad Filter using Hybrid Signed digit Number System

    Directory of Open Access Journals (Sweden)

    Sugandha Agarwal

    2012-03-01

    Full Text Available Speed of digital arithmetic processor depends mainly on the speed of adders. This paper provides a technique so that we can increase the speed of addition. Hybrid signed digit number representation perform addition in such a way that the carry propagation chain is limited to single digit position and hence are used to speed up arithmetic operation. Also hybrid signed digit reduces the critical path delay by parallelizing. Hybrid signed digit can be appropriate to use, when output is redundant representation.

  10. Fault tolerant, radiation hard, high performance digital signal processor

    Science.gov (United States)

    Holmann, Edgar; Linscott, Ivan R.; Maurer, Michael J.; Tyler, G. L.; Libby, Vibeke

    1990-01-01

    An architecture has been developed for a high-performance VLSI digital signal processor that is highly reliable, fault-tolerant, and radiation-hard. The signal processor, part of a spacecraft receiver designed to support uplink radio science experiments at the outer planets, organizes the connections between redundant arithmetic resources, register files, and memory through a shuffle exchange communication network. The configuration of the network and the state of the processor resources are all under microprogram control, which both maps the resources according to algorithmic needs and reconfigures the processing should a failure occur. In addition, the microprogram is reloadable through the uplink to accommodate changes in the science objectives throughout the course of the mission. The processor will be implemented with silicon compiler tools, and its design will be verified through silicon compilation simulation at all levels from the resources to full functionality. By blending reconfiguration with redundancy the processor implementation is fault-tolerant and reliable, and possesses the long expected lifetime needed for a spacecraft mission to the outer planets.

  11. Performance of digital integrated circuit technologies at very high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Prince, J.L.; Draper, B.L.; Rapp, E.A.; Kromberg, J.N.; Fitch, L.T.

    1980-01-01

    Results of investigations of the performance and reliability of digital bipolar and CMOS integrated circuits over the 25 to 340/sup 0/C range are reported. Included in these results are both parametric variation information and analysis of the functional failure mechanisms. Although most of the work was done using commercially available circuits (TTL and CMOS) and test chips from commercially compatible processes, some results of experimental simulations of dielectrically isolated CMOS are also discussed. It was found that commercial Schottky clamped TTL, and dielectrically isolated, low power Schottky-clamped TTL, functioned to junction temperatures in excess of 325/sup 0/C. Standard gold doped TTL functioned only to 250/sup 0/C, while commercial, isolated I/sup 2/L functioned to the range 250/sup 0/C to 275/sup 0/C. Commercial junction isolated CMOS, buffered and unbuffered, functioned to the range 280/sup 0/C to 310/sup 0/C/sup +/, depending on the manufacturer. Experimental simulations of simple dielectrically isolated CMOS integrated circuits, fabricated with heavier doping levels than normal, functioned to temperatures in excess of 340/sup 0/C. High temperature life testing of experimental, silicone-encapsulated simple TTL and CMOS integrated circuits have shown no obvious life limiting problems to date. No barrier to reliable functionality of TTL bipolar or CMOS integrated ciruits at temperatures in excess of 300/sup 0/C has been found.

  12. Effects of heavy ion radiation on digital micromirror device performance

    Science.gov (United States)

    Travinsky, Anton; Vorobiev, Dmitry; Ninkov, Zoran; Raisanen, Alan D.; Pellish, Jonny; Robberto, Massimo; Heap, Sara

    2016-09-01

    There is a pressing need in the astronomical community for space-suitable multiobject spectrometers (MOSs). Several digital micromirror device (DMD)-based prototype MOSs have been developed for ground-based observatories; however, their main use will come with deployment on a space-based mission. Therefore, the performance of DMDs under exoatmospheric radiation needs to be evaluated. DMDs were rewindowed with 2-μm thick pellicle and tested under accelerated heavy-ion radiation (control electronics shielded from radiation), with a focus on the detection of single-event effects (SEEs) including latch-up events. Testing showed that while DMDs are sensitive to nondestructive ion-induced state changes, all SEEs are cleared with a soft reset (i.e., sending a pattern to the device). The DMDs did not experience single-event induced permanent damage or functional changes that required a hard reset (power cycle), even at high ion fluences. This suggests that the SSE rate burden will be manageable for a DMD-based instrument when exposed to solar particle fluxes and cosmic rays in orbit.

  13. The Impact of Digital Skills on Educational Outcomes: Evidence from Performance Tests

    Science.gov (United States)

    Pagani, Laura; Argentin, Gianluca; Gui, Marco; Stanca, Luca

    2016-01-01

    Digital skills are increasingly important for labour market outcomes and social participation. Do they also matter for academic performance? This paper investigates the effects of digital literacy on educational outcomes by merging data from the Italian National Assessment in secondary schools with an original data-set on performance tests of…

  14. Digitization

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    Processes of digitization have for years represented a major trend in the developments of modern society but have only recently been related to processes of mediatization. The purpose of this article is to look into the relation between the concepts of mediatization and digitization and to clarify...... what a concept of digital media might add to the understanding of processes of mediatization and what the concept of mediatization might add to the understanding of digital media. It is argued that digital media open an array of new trajectories in human communication, trajectories which were...... not anticipated in previous conceptualizations of media and mediatization. If digital media are to be included, the concept of mediatization has to be revised and new parameters are to be built into the concept of media. At the same time it is argued that the concept of mediatization still provides a variety...

  15. Benchmarking the performance of fixed-image receptor digital radiography systems. Part 2: system performance metric.

    Science.gov (United States)

    Lee, Kam L; Bernardo, Michael; Ireland, Timothy A

    2016-06-01

    This is part two of a two-part study in benchmarking system performance of fixed digital radiographic systems. The study compares the system performance of seven fixed digital radiography systems based on quantitative metrics like modulation transfer function (sMTF), normalised noise power spectrum (sNNPS), detective quantum efficiency (sDQE) and entrance surface air kerma (ESAK). It was found that the most efficient image receptors (greatest sDQE) were not necessarily operating at the lowest ESAK. In part one of this study, sMTF is shown to depend on system configuration while sNNPS is shown to be relatively consistent across systems. Systems are ranked on their signal-to-noise ratio efficiency (sDQE) and their ESAK. Systems using the same equipment configuration do not necessarily have the same system performance. This implies radiographic practice at the site will have an impact on the overall system performance. In general, systems are more dose efficient at low dose settings.

  16. Bounds on the performance of a class of digital communication systems

    Science.gov (United States)

    Polk, D. R.; Gupta, S. C.; Cohn, D. L.

    1973-01-01

    Bounds on the capacity of a class of digital communication channels are derived. Equating the bounds on capacity to rate-distortion functions of (typical) sources in turn produces bounds on the performance of a class of digital communication systems. For ratios of squared quantization level to noise variance much less than one, the power requirements for this class of digital communication systems are shown to be within approximately 3 dB of the theoretical optimum.

  17. Digitizer of astronomical plates at Shanghai Astronomical Observatory and its performance test

    Science.gov (United States)

    Yu, Yong; Zhao, Jian-Hai; Tang, Zheng-Hong; Shang, Zheng-Jun

    2017-02-01

    Before CCD detectors were widely employed in observational astronomy, the main method of detection was the use of glass astrophotographic plates. Astronomical plates have been used to record information on the position and activity of celestial bodies for more than 100 years. There are about 30 000 astronomical plates in China, and the digitization of astronomical plates is of great significance for permanent preservation and to make full use of these valuable observation data. A digitizer with high precision and high measuring speed is a key piece of equipment for carrying out the task of digitizing these astronomical plates. A digitizer for glass astrophotographic plates was developed jointly by Shanghai Astronomical Observatory and Nishimura Co., Ltd of Japan. The digitizer’s hardware was manufactured by Nishimura Co., Ltd, and the performance test, error corrections as well as image processing of the digitizer were carried out by Shanghai Astronomical Observatory. The main structure and working mode of the digitizer are introduced in this paper. A performance test shows that brightness uniformity of illumination within the measuring area is better than 0.15%, the repeatability of digitized positions is better than 0.2 µm and the repeatability of digitized brightness is better than 0.01 instrumental magnitude. The systematic factors affecting digitized positions, such as lens distortion, the actual optical resolution, non-linearity of guide rails, non-uniformity of linear motors in the mobile platform, deviation of the image mosaic, and non-orthogonality between the direction of scanning and camera linear array, are calibrated and evaluated. Based on an astronomical plate with a size of 300mm × 300mm, which was digitized at different angles, the conversion residuals of positions of common stars on different images were investigated. The results show that the standard deviations of the residuals are better than 0.9 µm and the residual distribution is almost

  18. Digital Filtering Performance in the ATLAS Level-1 Calorimeter Trigger

    CERN Document Server

    Hadley, D R; The ATLAS collaboration

    2010-01-01

    The ATLAS Level-1 Calorimeter Trigger is a hardware-based system designed to identify high-pT jets, elec- tron/photon and tau candidates, and to measure total and missing ET in the ATLAS Liquid Argon and Tile calorimeters. It is a pipelined processor system, with a new set of inputs being evaluated every 25ns. The overall trigger decision has a latency budget of 2µs, including all transmission delays. The calorimeter trigger uses about 7200 reduced granularity analogue signals, which are first digitized at the 40 MHz LHC bunch-crossing frequency, before being passed to a digital Finite Impulse Re- sponse (FIR) filter. Due to latency and chip real-estate constraints, only a simple 5-element filter with limited precision can be used. Nevertheless, this filter achieves a significant reduction in noise, along with improving the bunch-crossing assignment and energy resolution for small signals. The context in which digital filters are used for the ATLAS Level-1 Calorimeter Trigger is presented, before descr...

  19. Digital Filter Performance for the ATLAS Level-1 Calorimeter Trigger

    CERN Document Server

    Hadley, D R; The ATLAS collaboration

    2010-01-01

    The ATLAS Level-1 Calorimeter Trigger is a hardware-based system designed to identify high-pT jets, electron/photon and tau candidates, and to measure total and missing ET in the ATLAS Liquid Argon and Tile calorimeters. It is a pipelined processor system, with a new set of inputs being evaluated every 25ns. The overall trigger decision has a latency budget of 2µs, including all transmission delays. The calorimeter trigger uses about 7200 reduced granularity analogue signals, which are first digitized at the 40 MHz LHC bunch-crossing frequency, before being passed to a digital Finite Impulse Response (FIR) filter. Due to latency and chip real-estate constraints, only a simple 5-element filter with limited precision can be used. Nevertheless this filter achieves a significant reduction in noise, along with improving the bunch-crossing assignment and energy resolution for small signals. The context in which digital filters are used for the ATLAS Level-1 Calorimeter Trigger will be presented, before describing ...

  20. Experimental Adaptive Digital Performance Monitoring for Optical DP-QPSK Coherent Receiver

    DEFF Research Database (Denmark)

    Borkowski, Robert; Zhang, Xu; Zibar, Darko;

    2011-01-01

    We report on a successful experimental demonstration of a digital optical performance monitoring (OPM) yielding satisfactory estimation accuracy along with adaptive impairment equalization. No observable penalty is measured when equalizer is driven by monitoring module....

  1. Performance of the SIR-B digital image processing subsystem

    Science.gov (United States)

    Curlander, J. C.

    1986-01-01

    A ground-based system to generate digital SAR image products has been developed and implemented in support of the SIR-B mission. This system is designed to achieve the maximum throughput while meeting strict image fidelity criteria. Its capabilities include: automated radiometric and geometric correction of the output imagery; high-precision absolute location without tiepoint registration; filtering of the raw data to remove spurious signals from alien radars; and automated catologing to maintain a full set of radar and image production facility in support of the SIR-B science investigators routinely produces over 80 image frames per week.

  2. JMorph: Software for performing rapid morphometric measurements on digital images of fossil assemblages

    Science.gov (United States)

    Lelièvre, Peter G.; Grey, Melissa

    2017-08-01

    Quantitative morphometric analyses of form are widely used in palaeontology, especially for taxonomic and evolutionary research. These analyses can involve several measurements performed on hundreds or even thousands of samples. Performing measurements of size and shape on large assemblages of macro- or microfossil samples is generally infeasible or impossible with traditional instruments such as vernier calipers. Instead, digital image processing software is required to perform measurements via suitable digital images of samples. Many software packages exist for morphometric analyses but there is not much available for the integral stage of data collection, particularly for the measurement of the outlines of samples. Some software exists to automatically detect the outline of a fossil sample from a digital image. However, automatic outline detection methods may perform inadequately when samples have incomplete outlines or images contain poor contrast between the sample and staging background. Hence, a manual digitization approach may be the only option. We are not aware of any software packages that are designed specifically for efficient digital measurement of fossil assemblages with numerous samples, especially for the purposes of manual outline analysis. Throughout several previous studies, we have developed a new software tool, JMorph, that is custom-built for that task. JMorph provides the means to perform many different types of measurements, which we describe in this manuscript. We focus on JMorph's ability to rapidly and accurately digitize the outlines of fossils. JMorph is freely available from the authors.

  3. Comparison of space analysis performed on plaster vs. digital dental casts applying Tanaka and Johnston's equation.

    Science.gov (United States)

    Sanches, Júlia Olien; dos Santos-Pinto, Lourdes Aparecida Martins; dos Santos-Pinto, Ary; Grehs, Betina; Jeremias, Fabiano

    2013-01-01

    The purpose of this study was to compare dental size measurements, their reproducibility and the application of Tanaka and Johnston regression equation in predicting the size of canines and premolars on plaster and digital dental casts. Thirty plaster casts were scanned and digitized. Mesiodistal measurements of the teeth were then performed with a digital caliper on the plaster and digital casts using O3d software system (Widialabs©).The sum of the sizes of the lower incisors was used to obtain predictive values of the sizes of the premolars and canines using the regression equation, and these values were compared with the actual sizes of the teeth. The data were statistically analyzed by applying to the results Pearson's correlation test, Dahlberg's formula, paired t-test and analysis of variance (p plaster and digital casts. Despite an adequate reproducibility of the measurements performed on both casts, most measurements on the digital casts were higher than those on the plaster casts. The predicted space was overestimated in both models and significantly higher in the digital casts.

  4. 75 FR 56873 - Digital Performance Right in Sound Recordings and Ephemeral Recordings

    Science.gov (United States)

    2010-09-17

    ... important educational message for students to learn the value of recorded music and to pay for it. 5/18/10... is that small noncommercial webcasters should pay only for the performances of music subject to the... Copyright Royalty Board 37 CFR Part 380 Digital Performance Right in Sound Recordings and...

  5. Children's Performance in Complex Listening Conditions: Effects of Hearing Loss and Digital Noise Reduction

    Science.gov (United States)

    Pittman, Andrea

    2011-01-01

    Purpose: To determine the effect of hearing loss (HL) on children's performance for an auditory task under demanding listening conditions and to determine the effect of digital noise reduction (DNR) on that performance. Method: Fifty children with normal hearing (NH) and 30 children with HL (8-12 years of age) categorized words in the presence of…

  6. Automated Performance Monitoring and Assessment for DCS Digital Systems.

    Science.gov (United States)

    1977-10-01

    eye opening monitor performance assessment techniques. (3) Implement and program a CPMAS test processor subsystem. (4) Perform a field test site...an internodal path in the planned DEB network is 11 ( Hillingdon to Schoenfeld). For this reason, the path from Node A to Node B in the Transmission...RADIOS SITE RADIOS HOHENSTADT 4 BANN 6 STUTTGART 4 HILLINGDON 3 LANGERKOPF 5 CROUGHTON 4 DONNERSBERG 10 MARTLESHAM HEATH 3 PIRMASENS 4 ADENAU 3

  7. Stability and performance analysis of a jump linear control system subject to digital upsets

    Institute of Scientific and Technical Information of China (English)

    王蕊; 孙辉; 马振洋

    2015-01-01

    This paper focuses on the methodology analysis for the stability and the corresponding tracking performance of a closed-loop digital jump linear control system with a stochastic switching signal. The method is applied to a flight control system. A distributed recoverable platform is implemented on the flight control system and subject to independent digital upsets. The upset processes are used to stimulate electromagnetic environments. Specifically, the paper presents the scenarios that the upset process is directly injected into the distributed flight control system, which is modeled by independent Markov upset processes and independent and identically distributed (IID) processes. A theoretical performance analysis and simulation modelling are both presented in detail for a more complete independent digital upset injection. The specific examples are proposed to verify the methodology of tracking performance analysis. The general analyses for different configurations are also proposed. Comparisons among different configurations are conducted to demonstrate the availability and the characteristics of the design.

  8. Performance indicators for the statistical evaluation of digital image classifications

    NARCIS (Netherlands)

    D'Urso, G.; Menenti, M.

    1996-01-01

    A statistical procedure is proposed to evaluate the algorithms for the numerical classification of images. The approach is based on the derivation of performance indicators from measurements of signature separability and thresholding analysis. Although these measurements are not new in image process

  9. Measuring User Performance during Interactions with Digital Video Collections.

    Science.gov (United States)

    Yang, Meng; Wildemuth, Barbara M.; Marchionini, Gary; Wilkens, Todd; Geisler, Gary; Hughes, Anthony; Gruss, Richard; Webster, Curtis

    2003-01-01

    Proposes two general classes of user tasks-recognition tasks and tasks requiring inference-for which performance measures were developed. The measures include graphical object recognition, textual object recognition, action recognition, free-text gist determination, multiple-choice gist determination and visual gist determination. Results from two…

  10. The Use of Digital Repositories for Enhancing Teacher Pedagogical Performance

    Science.gov (United States)

    Cohen, Anat; Kalimi, Sharon; Nachmias, Rafi

    2013-01-01

    This research examines the usage of local learning material repositories at school, as well as related teachers' attitudes and training. The study investigates the use of these repositories for enhancing teacher performance and assesses whether the assimilation of the local repositories increases their usage of and contribution to by teachers. One…

  11. Noise Performance Evaluation of the Candidate Digitizers for the MAJORANA DEMONSTRATOR

    Energy Technology Data Exchange (ETDEWEB)

    Aguayo Navarrete, Estanislao

    2011-03-16

    The noise performance evaluation of the two digitizer cards being considered for the MAJORANA DEMONSTRATOR (MJD) is presented in this document. The procurement of the data acquisition electronics for the MJD is scheduled to happen this year. At the time of writing this document, there are two candidate digitizer electronic boards. One aspect that is being considered by the collaboration is the feasibility of using the MJD for dark matter searches. The feasibility of using the MJD for this application is going to be dictated by the ability of the demonstrator to reach sub-keV energy resolution. One of the potential sources of noise in the MJD is the data acquisition system. This document will is concluded with a recommendation for the final digitizer board by comparing the noise performance of the two electronics systems. Noise parameters such as the effective number of bits, input range linearity and signal to noise ratio are experimentally determined. The two digitizer cards feature different on-board digital signal processing and these features are compared. The experimental set-up was also used to identify sources of noise. This paper describes these sources of noise in the data acquisition system, along with mitigation strategies. Issues such as grounding and wiring scheme have an impact in the overall data acquisition system performance and are discussed in detail. As a conclusion, the suitability of each one of the cards to become the back bone of the data acquisition system of the MJD is discussed.

  12. Digital control of high performance aircraft using adaptive estimation techniques

    Science.gov (United States)

    Van Landingham, H. F.; Moose, R. L.

    1977-01-01

    In this paper, an adaptive signal processing algorithm is joined with gain-scheduling for controlling the dynamics of high performance aircraft. A technique is presented for a reduced-order model (the longitudinal dynamics) of a high performance STOL aircraft. The actual controller views the nonlinear behavior of the aircraft as equivalent to a randomly switching sequence of linear models taken from a preliminary piecewise-linear fit of the system nonlinearities. The adaptive nature of the estimator is necessary to select the proper sequence of linear models along the flight trajectory. Nonlinear behavior is approximated by effective switching of the linear models at random times, with durations reflecting aircraft motion in response to pilot commands.

  13. Error performance analysis of coherent DCSK chaotic digital communication systems

    Institute of Scientific and Technical Information of China (English)

    李玉霞; 吴百海; 王光义; 丘水生

    2004-01-01

    An approach to calculating the approximate bit error rates for coherent DCSK in an AWGN channel is presented. By using logistic as the chaos generator and assuming ideal synchronization at the receiver, the BER of coherent DCSK in an AWGN channel is derived. The theoretical noise performance of coherent DCSK is again derived and is equal to that of coherent FSK. By computing and simulating, the theoretical BERs agree well with the simulated results.

  14. FIPSER: Performance Study of a Readout Concept With Few Digitization Levels for Fast Signals

    CERN Document Server

    Limyansky, Brent; Cressler, John D; Otte, Adam Nepomuk; Taboada, Ignacio; Ulusoy, Cagri

    2016-01-01

    We discuss the performance of a readout system, Fixed Pulse Shape Efficient Readout (FIPSER), to digitize signals from detectors with a fixed pulse shape. In this study we are mainly interested in the readout of fast photon detectors like photomultipliers or Silicon photomultipliers. But the concept can be equally applied to the digitization of other detector signals. FIPSER is based on the flash analog to digital converter (FADC) concept, but has the potential to lower costs and power consumption by using an order of magnitude fewer discrete voltage levels. Performance is bolstered by combining the discretized signal with the knowledge of the underlying pulse shape. Simulated FIPSER data was reconstructed with two independent methods. One using a maximum likelihood method and the other using a modified chisquared test. Both methods show that utilizing 12 discrete voltage levels with a sampling rate of 4 samples per full width half maximum (FWHM) of the pulse achieves an amplitude resolution that is better th...

  15. Toward high-performance digital logic technology with carbon nanotubes.

    Science.gov (United States)

    Tulevski, George S; Franklin, Aaron D; Frank, David; Lobez, Jose M; Cao, Qing; Park, Hongsik; Afzali, Ali; Han, Shu-Jen; Hannon, James B; Haensch, Wilfried

    2014-09-23

    The slow-down in traditional silicon complementary metal-oxide-semiconductor (CMOS) scaling (Moore's law) has created an opportunity for a disruptive innovation to bring the semiconductor industry into a postsilicon era. Due to their ultrathin body and ballistic transport, carbon nanotubes (CNTs) have the intrinsic transport and scaling properties to usher in this new era. The remaining challenges are largely materials-related and include obtaining purity levels suitable for logic technology, placement of CNTs at very tight (∼5 nm) pitch to allow for density scaling and source/drain contact scaling. This review examines the potential performance advantages of a CNT-based computing technology, outlines the remaining challenges, and describes the recent progress on these fronts. Although overcoming these issues will be challenging and will require a large, sustained effort from both industry and academia, the recent progress in the field is a cause for optimism that these materials can have an impact on future technologies.

  16. Digital Devices, Distraction, and Student Performance: Does In-Class Cell Phone Use Reduce Learning?

    Science.gov (United States)

    Duncan, Douglas K.; Hoekstra, Angel R.; Wilcox, Bethany R.

    2012-01-01

    The recent increase in use of digital devices such as laptop computers, iPads, and web-enabled cell phones has generated concern about how technologies affect student performance. Combining observation, survey, and interview data, this research assesses the effects of technology use on student attitudes and learning. Data were gathered in eight…

  17. Exploration of a digital audio processing platform using a compositional system level performance estimation framework

    DEFF Research Database (Denmark)

    Tranberg-Hansen, Anders Sejer; Madsen, Jan

    2009-01-01

    This paper presents the application of a compositional simulation based system-level performance estimation framework on a non-trivial industrial case study. The case study is provided by the Danish company Bang & Olufsen ICEpower a/s and focuses on the exploration of a digital mobile audio...

  18. 75 FR 16377 - Digital Performance Right in Sound Recordings and Ephemeral Recordings

    Science.gov (United States)

    2010-04-01

    ... From the Federal Register Online via the Government Publishing Office LIBRARY OF CONGRESS Copyright Royalty Board 37 CFR Part 380 Digital Performance Right in Sound Recordings and Ephemeral... Copyright Royalty Judges are publishing for comment proposed regulations governing the rates and terms...

  19. 75 FR 6097 - Digital Performance Right in Sound Recordings and Ephemeral Recordings

    Science.gov (United States)

    2010-02-08

    ... From the Federal Register Online via the Government Publishing Office LIBRARY OF CONGRESS Copyright Royalty Board 37 CFR Part 380 Digital Performance Right in Sound Recordings and Ephemeral... Royalty Judges are publishing final regulations governing the statutory minimum fees to be paid...

  20. In search of design principles for developing digital learning & performance support for a student design task

    NARCIS (Netherlands)

    Bollen, Lars; Van der Meij, Hans; Leemkuil, Henny; McKenney, Susan

    2016-01-01

    A digital learning and performance support environment for university student design tasks was developed. This paper describes on the design rationale, process, and the usage results to arrive at a core set of design principles for the construction of such an environment. We present a collection of

  1. In search of design principles for developing digital learning & performance support for a student design task

    NARCIS (Netherlands)

    Bollen, Lars; Meij, van der Hans; Leemkuil, Henny; McKenney, Susan

    2015-01-01

    A digital learning and performance support environment for university student design tasks was developed. This paper describes on the design rationale, process, and the usage results to arrive at a core set of design principles for the construction of such an environment. We present a collection of

  2. The Role of Online Reader Experience in Explaining Students' Performance in Digital Reading

    Science.gov (United States)

    Gil-Flores, Javier; Torres-Gordillo, Juan-Jesus; Perera-Rodriguez, Victor-Hugo

    2012-01-01

    This study explores the relationship between students' extracurricular experiences online and their performance on the Program for International Student Assessment (PISA), focusing specifically on students' competence in digital reading. The study uses a descriptive, correlational, ex post facto design. The data are taken from Spanish students'…

  3. Health Education Field Experience Stories: A Reflective, Digital, Performance-Based Project

    Science.gov (United States)

    Lyde, Adrian R.

    2012-01-01

    This article describes a reflective, systematic, performance-based project resulting in the development of a digital story about a community health education field experience. The project is designed for preservice health education students at the college/university level. The primary benefit of the project is that it challenges students to engage…

  4. In search of design principles for developing digital learning & performance support for a student design task

    NARCIS (Netherlands)

    Bollen, Lars; Van der Meij, Hans; Leemkuil, Henny; McKenney, Susan

    2016-01-01

    A digital learning and performance support environment for university student design tasks was developed. This paper describes on the design rationale, process, and the usage results to arrive at a core set of design principles for the construction of such an environment. We present a collection of

  5. In search of design principles for developing digital learning & performance support for a student design task

    NARCIS (Netherlands)

    Bollen, Lars; van der Meij, Hans; Leemkuil, Hendrik H.; McKenney-Jensh, Susan E.

    2015-01-01

    A digital learning and performance support environment for university student design tasks was developed. This paper describes on the design rationale, process, and the usage results to arrive at a core set of design principles for the construction of such an environment. We present a collection of

  6. Relation between Academic Performance and Students' Engagement in Digital Learning Activities

    Science.gov (United States)

    Bertheussen, Bernt Arne; Myrland, Øystein

    2016-01-01

    This study reports on the effect of student engagement in digital learning activities on academic performance for 120 students enrolled in an undergraduate finance course. Interactive practice and exam problem files were available to each student, and individual download activity was automatically recorded during the first 50 days of the course.…

  7. Digital Devices, Distraction, and Student Performance: Does In-Class Cell Phone Use Reduce Learning?

    Science.gov (United States)

    Duncan, Douglas K.; Hoekstra, Angel R.; Wilcox, Bethany R.

    2012-01-01

    The recent increase in use of digital devices such as laptop computers, iPads, and web-enabled cell phones has generated concern about how technologies affect student performance. Combining observation, survey, and interview data, this research assesses the effects of technology use on student attitudes and learning. Data were gathered in eight…

  8. The Role of Online Reader Experience in Explaining Students' Performance in Digital Reading

    Science.gov (United States)

    Gil-Flores, Javier; Torres-Gordillo, Juan-Jesus; Perera-Rodriguez, Victor-Hugo

    2012-01-01

    This study explores the relationship between students' extracurricular experiences online and their performance on the Program for International Student Assessment (PISA), focusing specifically on students' competence in digital reading. The study uses a descriptive, correlational, ex post facto design. The data are taken from Spanish students'…

  9. Does Navigation Always Predict Performance? Effects of Navigation on Digital Reading Are Moderated by Comprehension Skills

    Science.gov (United States)

    Naumann, Johannes; Salmerón, Ladislao

    2016-01-01

    This study investigated interactive effects of navigation and offline comprehension skill on digital reading performance. As indicators of navigation, relevant page selection and irrelevant page selection were considered. In 533 Spanish high school students aged 11-17 positive effects of offline comprehension skill and relevant page selection on…

  10. Digital Game-Based Learning Supports Student Motivation, Cognitive Success, and Performance Outcomes

    Science.gov (United States)

    Woo, Jeng-Chung

    2014-01-01

    Traditional multimedia learning is primarily based on the cognitive load concept of information processing theory. Recent digital game-based learning (DGBL) studies have focused on exploring content support for learning motivation and related game characteristics. Motivation, volition, and performance (MVP) theory indicates that cognitive load and…

  11. Implementation and Performance of GaAs Digital Signal Processing ASICs

    Science.gov (United States)

    Whitaker, William D.; Buchanan, Jeffrey R.; Burke, Gary R.; Chow, Terrance W.; Graham, J. Scott; Kowalski, James E.; Lam, Barbara; Siavoshi, Fardad; Thompson, Matthew S.; Johnson, Robert A.

    1993-01-01

    The feasibility of performing high speed digital signal processing in GaAs gate array technology has been demonstrated with the successful implementation of a VLSI communications chip set for NASA's Deep Space Network. This paper describes the techniques developed to solve some of the technology and implementation problems associated with large scale integration of GaAs gate arrays.

  12. An integrated device with high performance multi-function generators and time-to-digital convertors

    Science.gov (United States)

    Qin, X.; Shi, Z.; Xie, Y.; Wang, L.; Rong, X.; Jia, W.; Zhang, W.; Du, J.

    2017-01-01

    A highly integrated, high performance, and re-configurable device, which is designed for the Nitrogen-Vacancy (N-V) center based quantum applications, is reported. The digital compartment of the device is fully implemented in a Field-Programmable-Gate-Array (FPGA). The digital compartment is designed to manage the multi-function digital waveform generation and the time-to-digital convertors. The device provides two arbitrary-waveform-generator channels which operate at a 1 Gsps sampling rate with a maximum bandwidth of 500 MHz. There are twelve pulse channels integrated in the device with a 50 ps time resolution in both duration and delay. The pulse channels operate with the 3.3 V transistor-transistor logic. The FPGA-based time-to-digital convertor provides a 23-ps time measurement precision. A data accumulation module, which can record the input count rate and the distributions of the time measurement, is also available. A digital-to-analog convertor board is implemented as the analog compartment, which converts the digital waveforms to analog signals with 500 MHz lowpass filters. All the input and output channels of the device are equipped with 50 Ω SubMiniature version A termination. The hardware design is modularized thus it can be easily upgraded with compatible components. The device is suitable to be applied in the quantum technologies based on the N-V centers, as well as in other quantum solid state systems, such as quantum dots, phosphorus doped in silicon, and defect spins in silicon carbide.

  13. An integrated device with high performance multi-function generators and time-to-digital convertors.

    Science.gov (United States)

    Qin, X; Shi, Z; Xie, Y; Wang, L; Rong, X; Jia, W; Zhang, W; Du, J

    2017-01-01

    A highly integrated, high performance, and re-configurable device, which is designed for the Nitrogen-Vacancy (N-V) center based quantum applications, is reported. The digital compartment of the device is fully implemented in a Field-Programmable-Gate-Array (FPGA). The digital compartment is designed to manage the multi-function digital waveform generation and the time-to-digital convertors. The device provides two arbitrary-waveform-generator channels which operate at a 1 Gsps sampling rate with a maximum bandwidth of 500 MHz. There are twelve pulse channels integrated in the device with a 50 ps time resolution in both duration and delay. The pulse channels operate with the 3.3 V transistor-transistor logic. The FPGA-based time-to-digital convertor provides a 23-ps time measurement precision. A data accumulation module, which can record the input count rate and the distributions of the time measurement, is also available. A digital-to-analog convertor board is implemented as the analog compartment, which converts the digital waveforms to analog signals with 500 MHz lowpass filters. All the input and output channels of the device are equipped with 50 Ω SubMiniature version A termination. The hardware design is modularized thus it can be easily upgraded with compatible components. The device is suitable to be applied in the quantum technologies based on the N-V centers, as well as in other quantum solid state systems, such as quantum dots, phosphorus doped in silicon, and defect spins in silicon carbide.

  14. A RESEARCH ON HIGH -PERFORMANCE ANALOG-TO-DIGITAL CONVERTERS IN WIRELESS COMMUNICATION SYSTEMSIN

    OpenAIRE

    伊藤, 朋彦; ITO,Tomohiko

    2014-01-01

    To realize next-generation high-throughput wireless communication systems, it is essential to develop analog-to-digital converters (ADC) with high conversion speed, high resolution, low power, and low operational supply voltage. In this work, the design methodologies and the new circuit architectures for these high-performance ADCs are researched.First, the methods to optimize these performances for ADCs were confirmed. In a pipeline ADC which is promising to realize the high-throughput syste...

  15. Catalyzing healthcare transformation with digital health: Performance indicators and lessons learned from a Digital Health Innovation Group.

    Science.gov (United States)

    Tseng, Jocelyn; Samagh, Sonia; Fraser, Donna; Landman, Adam B

    2017-09-25

    Despite considerable investment in digital health (DH) companies and a growing DH ecosystem, there are multiple challenges to testing and implementing innovative solutions. Health systems have recognized the potential of DH and have formed DH innovation centers. However, limited information is available on DH innovation center processes, best practices, or outcomes. This case report describes a DH innovation center process that can be replicated across health systems and defines and benchmarks process indicators to assess DH innovation center performance. The Brigham and Women's Hospital's Digital Health Innovation Group (DHIG) accelerates DH innovations from idea to pilot safely and efficiently using a structured process. Fifty-four DH innovations were accelerated by the DHIG process between July 2014 and December 2016. In order to measure effectiveness of the DHIG process, key process indicators were defined as 1) number of solutions that completed each DHIG phase and 2) length of time to complete each phase. Twenty-three DH innovations progressed to pilot stage and 13 innovations were terminated after barriers to pilot implementation were identified by the DHIG process. For 4 DH solutions that executed a pilot, the average time for innovations to proceed from DHIG intake to pilot initiation was 9 months. Overall, the DHIG is a reproducible process that addresses key roadblocks in DH innovation within health systems. To our knowledge, this is the first report to describe DH innovation process indicators and results within an academic health system. Therefore, there is no published data to compare our results with the results of other DH innovation centers. Standardized data collection and indicator reporting could allow benchmark comparisons across institutions. Additional opportunities exist for the validation of DH solution effectiveness and for translational support from pilot to implementation. These are critical steps to advance DH technologies and

  16. Comparison of five digital scintigraphic display modes. An ROC curve analysis of detection performance.

    Science.gov (United States)

    Goin, J E; Preston, D F; Gallagher, J H; Wegst, A V

    1983-01-01

    In the last decade diagnostic imaging departments, even those of moderate size, have experienced unprecedented growth. Much of this expansion can be attributed directly to technological developments, including systems for the acquisition of diagnostic images in digital format. In modern imaging departments, digital-based systems are quite common and are found across the specialities of nuclear medicine, ultrasound, transmission and emission computed tomography, and angiography. Nuclear magnetic resonance is the newest digital-based modality, and it appears destined to achieve its place in the diagnostic arsenal. These systems all have one trait in common, which is the topic of this paper. They offer the potential of increasing diagnostic accuracy by varying the methods used to process and display the acquired imaged data. We present the results of a nuclear medicine study designed to compare observer performance among five digital scintigraphic display modes. The observer's task was to detect artificially created lesions in brain scintigrams. Each mode is defined by a combination of an image processing function and a method of display. Using 40 trained observers, a receiver operating characteristic curve analysis was performed. The results support the use of color displays in nuclear medicine.

  17. Performance analysis of digital FM demodulators for fading channels in the threshold region

    Science.gov (United States)

    Dharamsi, M. T.; Gupta, S. C.

    1976-01-01

    The quasi-optimum digital FM demodulators for fading channels reported earlier (1975) reflected the system performance accurately under high signal to noise ratio conditions. In this paper, the prediction of the system performance for low SNR values is considered. A new set of error variance algorithms is developed from the filter algorithm assuming a Gaussian distribution for the state estimation errors and taking the effect of high frequency terms into consideration. Simulation analysis for an FM system with Rician fading channel shows that these algorithms predict the system performance accurately in the threshold region.

  18. Digital Game Playing Motives among Adolescents: Relations to Parent-Child Communication, School Performance, Sleeping Habits, and Perceived Health

    Science.gov (United States)

    Wallenius, Marjut; Rimpela, Arja; Punamaki, Raija-Leena; Lintonen, Tomi

    2008-01-01

    The aims of this research were to describe Finnish adolescents' different motives for digital game playing, and to examine relations between digital game playing and parent-child communication, school performance, sleeping habits, and perceived health. A questionnaire was used to assess a nationwide postal sample of 12-18-year-old Finns (6761…

  19. Does Performance in Digital Reading Relate to Computer Game Playing? A Study of Factor Structure and Gender Patterns in 15-Year-Olds' Reading Literacy Performance

    Science.gov (United States)

    Rasmusson, Maria; Åberg-Bengtsson, Lisbeth

    2015-01-01

    Data from a Swedish PISA-sample were used (1) to identify a digital reading factor, (2) to investigate gender differences in this factor (if found), and (3) to explore how computer game playing might relate to digital reading performance and gender. The analyses were conducted with structural equation modeling techniques. In addition to an overall…

  20. Performance Evaluation of Digital Coherent Receivers for Phase-Modulated Radio-Over-Fiber Links

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Zibar, Darko; Tafur Monroy, Idelfonso

    2011-01-01

    The performance of optical phase-modulated (PM) radio-over-fiber (RoF) links assisted with coherent detection and digital signal processing (PM-Coh) is analyzed and experimentally demonstrated for next-generation wireless-over-fiber systems. PM-Coh offers high linearity for transparent transport......-bandwidth electronics. Analytical assessment and simulations are used to determine the ultimate performance with respect to laser linewidth, modulation index, and receiver sensitivity. Then, two different scenarios are studied and experimentally demonstrated as an application of PM-Coh links: a high...

  1. Performance Analysis of a Fast Digital Integrator for Magnetic Field Measurements at CERN

    CERN Document Server

    Arpaia, P; Masi, A; Spiezia, G

    2007-01-01

    A Fast Digital Integrator (FDI) has been designed at CERN for increasing performance of state-of-art instruments analyzing superconducting magnets in particle accelerators. In particular, in flux measurement, a bandwidth up to 50-100 kHz and an accuracy of 10 ppm has to be targeted. In this paper, basic concepts and architecture of the developed FDI are highlighted. Numerical metrological analysis of the instrument performance is shown, by focusing both on deterministic errors and on uncertainty in time and amplitude domains.

  2. WISC-IV unusual digit span performance in a sample of adolescents with learning disabilities.

    Science.gov (United States)

    Harrison, Allyson G; Armstrong, Irene

    2014-01-01

    Accurate identification of symptom magnification is essential when determining whether or not obtained test data are valid or interpretable. Apart from using freestanding symptom validity tests, many researchers encourage use of embedded measures of test-related motivation, including ones derived from the Digit Span subtest of the Wechsler scales. Such embedded measures are based on identification of performance patterns that are implausible if the test taker is investing full effort; however, it is unclear whether or not persons with preexisting cognitive difficulties such as specific learning disabilities (LD) might be falsely accused of poor test motivation due to actual but impaired working-memory skills. This study examined the specificity of such measures by reviewing performance of 86 adolescents with LDs on three measures embedded in the Wechsler Intelligence Scale for Children-Fourth Edition-namely, Digit Span (DS), Vocabulary-DS differences, and Reliable Digit Span (RDS) scores. Results indicate that while RDS is likely insensitive to impairments associated with LD, other DS measures may have an unacceptably high false-positive rate, especially if Canadian normative data are used to calculate scores.

  3. PERFORMANCE ANALYSIS OF SECURE MEDICAL IMAGE COMMUNICATION WITH DIGITAL SIGNATURE AND REVERSIBLE WATERMARKING

    Directory of Open Access Journals (Sweden)

    A. Umamageswari

    2013-08-01

    Full Text Available Protection of Medical image contents becomes the important issue in computer network security. Digital Watermarking has becomes a promising technique for medical content authentication, it allows to embed relevant information with the image, which provides confidentiality, integrity and authentication by embedding Digital Signature (DS with the Medical image. In this paper we focus on need for reversible watermarking, Medical Image Compression and security related problems in medical images, it comparing the performances of various lossless watermarking techniques for various medical image modalities like MRI (Magnetic Resonance Imaging, US (Ultrasonic, CT (Computed Tomography, Endoscopic and Angiographic images. Region of Interest (ROI supporting lossless watermarking systems only considered for discussions. Performance of all lossless watermarking with Digital Signature is analyzed by means of four parameters Capacity Rate, PSNR (Peak Signal to Noise ratio, NPCR (Number of Pixel Change Rate and Compression Ratio (CR. This Paper also introduces new mechanism for open network security for medical images. This lossless watermarking is responsible for recovering the altered medical image content of the system.

  4. Simulation of the High Performance Time to Digital Converter for the ATLAS Muon Spectrometer trigger upgrade

    Science.gov (United States)

    Meng, X. T.; Levin, D. S.; Chapman, J. W.; Zhou, B.

    2016-09-01

    The ATLAS Muon Spectrometer endcap thin-Resistive Plate Chamber trigger project compliments the New Small Wheel endcap Phase-1 upgrade for higher luminosity LHC operation. These new trigger chambers, located in a high rate region of ATLAS, will improve overall trigger acceptance and reduce the fake muon trigger incidence. These chambers must generate a low level muon trigger to be delivered to a remote high level processor within a stringent latency requirement of 43 bunch crossings (1075 ns). To help meet this requirement the High Performance Time to Digital Converter (HPTDC), a multi-channel ASIC designed by CERN Microelectronics group, has been proposed for the digitization of the fast front end detector signals. This paper investigates the HPTDC performance in the context of the overall muon trigger latency, employing detailed behavioral Verilog simulations in which the latency in triggerless mode is measured for a range of configurations and under realistic hit rate conditions. The simulation results show that various HPTDC operational configurations, including leading edge and pair measurement modes can provide high efficiency (>98%) to capture and digitize hits within a time interval satisfying the Phase-1 latency tolerance.

  5. FIPSER: Performance study of a readout concept with few digitization levels for fast signals

    Science.gov (United States)

    Limyansky, B.; Reese, R.; Cressler, J. D.; Otte, A. N.; Taboada, I.; Ulusoy, C.

    2016-11-01

    We discuss the performance of a readout system, Fixed Pulse Shape Efficient Readout (FIPSER), to digitize signals from detectors with a fixed pulse shape. In this study we are mainly interested in the readout of fast photon detectors like photomultipliers or Silicon photomultipliers. But the concept can be equally applied to the digitization of other detector signals. FIPSER is based on the flash analog to digital converter (FADC) concept, but has the potential to lower costs and power consumption by using an order of magnitude fewer discrete voltage levels. Performance is bolstered by combining the discretized signal with the knowledge of the underlying pulse shape. Simulated FIPSER data was reconstructed with two independent methods. One using a maximum likelihood method and the other using a modified χ2 test. Both methods show that utilizing 12 discrete voltage levels with a sampling rate of 4 samples per full width half maximum (FWHM) of the pulse achieves an amplitude resolution that is better than the Poisson limit for photon-counting experiments. The time resolution achieved in this configuration ranges between 0.02 and 0.16 FWHM and depends on the pulse amplitude. In a situation where the waveform is composed of two consecutive pulses the pulses can be separated if they are at least 0.05-0.30 FWHM apart with an amplitude resolution that is better than 20%.

  6. A Framework for Evaluating the Effects of Degraded Digital I and C Systems on Human Performance

    Energy Technology Data Exchange (ETDEWEB)

    OHara,J.; Gunther, B.; Hughes, N.; Barnes, V.

    2009-04-09

    New and advanced reactors will use integrated digital instrumentation and control (I&C) systems to support operators in their monitoring and control functions. Even though digital systems are typically highly reliable, their potential for degradation or failure could significantly affect operator situation awareness and performance and, consequently, impact plant safety. The U.S. Nuclear Regulatory Commission has initiated a research project to investigate the effects of degraded I&C systems on human performance and plant operations. The ultimate objective of this project is to develop the technical basis for human factors review guidance for conditions of degraded I&C, including complete failure. Based on the results of this effort, NRC will determine the need for developing new guidance or revising NUREG-0800, NUREG-0711, NUREG-0700 and other pertinent NRC review guidance. This paper reports on the first phase of the research, the development of a framework for linking degraded I&C system conditions to human performance. The framework consists of three levels: I&C subsystems, human-system interfaces, and human performance. Each level is composed of a number of discrete elements. This paper will describe the elements at each level and their integration. In the next phase of the research, the framework will be used to systematically investigate the human performance consequences of various classes of failures.

  7. Performance of digital radiography with enhancement filters for the diagnosis of proximal caries

    Directory of Open Access Journals (Sweden)

    Manuella Dias Furtado Belém

    2013-06-01

    Full Text Available Enhancement filters are potentially supposed to improve the diagnostic performance of digital images. Thus, the aim of this study was to compare the performance of digital radiography with and without enhancement filters for the detection of induced proximal caries lesions. The total sample consisted of 120 sound human teeth (40 premolars, 80 molars. Enamel subsurface demineralization was induced in one of the proximal surfaces of 60 teeth. Standardized radiographs of all teeth were acquired after the demineralization phase using the Digora-Optime® system. Four radiologists examined the digital radiographs and applied the following filters provided by the Digora® for Windows 2.6 package: Negative, Sharpen and both (Negative plus Sharpen. Validation of radiographic diagnosis was carried out by Knoop cross-sectional micro-hardness profiling on the proximal surfaces. Intraobserver agreement was estimated using Kappa statistics (k. Sensitivity, specificity and over-all accuracy were compared using ANOVA/Tukey test (α = 5%. Intraobserver agreement ranged from good to very good/optimal (k: 0.65–0.83. Although not statistically significant, the highest sensitivity (0.68 ± 0.22 and accuracy (0.76 ± 0.16 values were observed using the Sharpen filter as opposed to the Negative filter, which presented the lowest performance indices (0.57 ± 0.13 and 0.70 ± 0.10, respectively. Specificity ranged from 0.84 to 0.85, considering all imaging modalities (p > 0.05. Insofar as the Sharpen filter had the highest performance indices, it may be considered a useful adjunct for detecting subtle proximal caries lesions.

  8. High performance digital read out integrated circuit (DROIC) for infrared imaging

    Science.gov (United States)

    Mizuno, Genki; Olah, Robert; Oduor, Patrick; Dutta, Achyut K.; Dhar, Nibir K.

    2016-05-01

    Banpil Photonics has developed a high-performance Digital Read-Out Integrated Circuit (DROIC) for image sensors and camera systems targeting various military, industrial and commercial Infrared (IR) imaging applications. The on-chip digitization of the pixel output eliminates the necessity for an external analog-to-digital converter (ADC), which not only cuts costs, but also enables miniaturization of packaging to achieve SWaP-C camera systems. In addition, the DROIC offers new opportunities for greater on-chip processing intelligence that are not possible in conventional analog ROICs prevalent today. Conventional ROICs, which typically can enhance only one high performance attribute such as frame rate, power consumption or noise level, fail when simultaneously targeting the most aggressive performance requirements demanded in imaging applications today. Additionally, scaling analog readout circuits to meet such requirements leads to expensive, high-power consumption with large and complex systems that are untenable in the trend towards SWaP-C. We present the implementation of a VGA format (640x512 pixels 15μm pitch) capacitivetransimpedance amplifier (CTIA) DROIC architecture that incorporates a 12-bit ADC at the pixel level. The CTIA pixel input circuitry has two gain modes with programmable full-well capacity values of 100K e- and 500K e-. The DROIC has been developed with a system-on-chip architecture in mind, where all the timing and biasing are generated internally without requiring any critical external inputs. The chip is configurable with many parameters programmable through a serial programmable interface (SPI). It features a global shutter, low power, and high frame rates programmable from 30 up 500 frames per second in full VGA format supported through 24 LVDS outputs. This DROIC, suitable for hybridization with focal plane arrays (FPA) is ideal for high-performance uncooled camera applications ranging from near IR (NIR) and shortwave IR (SWIR) to mid

  9. Amorphous Zinc Oxide Integrated Wavy Channel Thin Film Transistor Based High Performance Digital Circuits

    KAUST Repository

    Hanna, Amir

    2015-12-04

    High performance thin film transistor (TFT) can be a great driving force for display, sensor/actuator, integrated electronics, and distributed computation for Internet of Everything applications. While semiconducting oxides like zinc oxide (ZnO) present promising opportunity in that regard, still wide area of improvement exists to increase the performance further. Here, we show a wavy channel (WC) architecture for ZnO integrated TFT which increases transistor width without chip area penalty, enabling high performance in material agnostic way. We further demonstrate digital logic NAND circuit using the WC architecture and compare it to the conventional planar architecture. The WC architecture circuits have shown 2× higher peak-to-peak output voltage for the same input voltage. They also have 3× lower high-to-low propagation delay times, respectively, when compared to the planar architecture. The performance enhancement is attributed to both extra device width and enhanced field effect mobility due to higher gate field electrostatics control.

  10. Optical digital to analog conversion performance analysis for indoor set-up conditions

    Science.gov (United States)

    Dobesch, Aleš; Alves, Luis Nero; Wilfert, Otakar; Ribeiro, Carlos Gaspar

    2017-10-01

    In visible light communication (VLC) the optical digital to analog conversion (ODAC) approach was proposed as a suitable driving technique able to overcome light-emitting diode's (LED) non-linear characteristic. This concept is analogous to an electrical digital-to-analog converter (EDAC). In other words, digital bits are binary weighted to represent an analog signal. The method supports elementary on-off based modulations able to exploit the essence of LED's non-linear characteristic allowing simultaneous lighting and communication. In the ODAC concept the reconstruction error does not simply rely upon the converter bit depth as in case of EDAC. It rather depends on communication system set-up and geometrical relation between emitter and receiver as well. The paper describes simulation results presenting the ODAC's error performance taking into account: the optical channel, the LED's half power angle (HPA) and the receiver field of view (FOV). The set-up under consideration examines indoor conditions for a square room with 4 m length and 3 m height, operating with one dominant wavelength (blue) and having walls with a reflection coefficient of 0.8. The achieved results reveal that reconstruction error increases for higher data rates as a result of interference due to multipath propagation.

  11. Performance of residents using digital images versus glass slides on certification examination in anatomical pathology: a mixed methods pilot study

    Science.gov (United States)

    Mirham, Lorna; Naugler, Christopher; Hayes, Malcolm; Ismiil, Nadia; Belisle, Annie; Sade, Shachar; Streutker, Catherine; MacMillan, Christina; Rasty, Golnar; Popovic, Snezana; Joseph, Mariamma; Gabril, Manal; Barnes, Penny; Hegele, Richard G.; Carter, Beverley; Yousef, George M.

    2016-01-01

    Background: It is anticipated that many licensing examination centres for pathology will begin fully digitizing the certification examinations. The objective of our study was to test the feasibility of a fully digital examination and to assess the needs, concerns and expectations of pathology residents in moving from a glass slide-based examination to a fully digital examination. Methods: We conducted a mixed methods study that compared, after randomization, the performance of senior residents (postgraduate years 4 and 5) in 7 accredited anatomical pathology training programs across Canada on a pathology examination using either glass slides or digital whole-slide scanned images of the slides. The pilot examination was followed by a post-test survey. In addition, pathology residents from all levels of training were invited to participate in an online survey. Results: A total of 100 residents participated in the pilot examination; 49 were given glass slides instead of digital images. We found no significant difference in examination results between the 2 groups of residents (estimated marginal mean 8.23/12, 95% confidence interval [CI] 7.72-8.87, for glass slides; 7.84/12, 95% CI 7.28-8.41, for digital slides). In the post-test survey, most of the respondents expressed concerns with the digital examination, including slowly functioning software, blurring and poor detail of images, particularly nuclear features. All of the respondents of the general survey (n = 179) agreed that additional training was required if the examination were to become fully digital. Interpretation: Although the performance of residents completing pathology examinations with glass slides was comparable to that of residents using digital images, our study showed that residents were not comfortable with the digital technology, especially given their current level of exposure to it. Additional training may be needed before implementing a fully digital examination, with consideration for a

  12. Decontamination of digital image sensors and assessment of electron microscope performance in a BSL-3 containment

    Directory of Open Access Journals (Sweden)

    Michael B. Sherman

    2015-05-01

    Full Text Available A unique biological safety level (BSL-3 cryo-electron microscopy facility with a 200 keV high-end cryo-electron microscope has been commissioned at the University of Texas Medical Branch (UTMB to study the structure of viruses and bacteria classified as select agents. We developed a microscope decontamination protocol based on chlorine dioxide gas with a continuous flow system. In this paper we report on testing digital camera sensors (both CCD and CMOS direct detector in a BSL-3 environment, and microscope performance after chlorine dioxide (ClO2 decontamination cycles.

  13. Description and Performance of an L-Band Radiometer with Digital Beamforming

    Directory of Open Access Journals (Sweden)

    Juan F. Marchan-Hernandez

    2010-12-01

    Full Text Available This paper presents the description and performance tests of an L-band microwave radiometer with Digital Beamforming (DBF, developed for the Passive Advanced Unit (PAU for ocean monitoring project. PAU is an instrument that combines, in a single receiver and without time multiplexing, a microwave radiometer at L-band (PAU-RAD and a GPS-reflectometer (PAU-GNSS-R. This paper focuses on the PAU‑RAD beamformer’s first results, analyzing the hardware and software required for the developed prototype. Finally, it discusses the first results measured in the Universitat Politècnica de Catalunya (UPC anechoic chamber.

  14. Human Computer Confluence in Rehabilitation: Digital Media Plasticity and Human Performance Plasticity

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2013-01-01

    approaches promoting mindsets and activities commonly considered enduring, mundane and boring. The concept focuses on sensor-based interfaces mapped to control tailored-content that acts as direct and immediate feedbacks mirroring input. These flexible, adaptive, and ‘plastic’ options offer facilitators new......Digital media plasticity evocative to embodied interaction is presented as a utilitarian tool when mixed and matched to target human performance potentials specific to nuance of development for those with impairment. A distinct intervention strategy trains via alternative channeling of external...

  15. The effects of digital image processing for noise reduction on observer performance

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Young Chul; Choi, Bo Ram; Huh, Kyung Hoi; Yi, Won Jin; Heo, Min Suk; Lee, Sam Sun; Choi, Soon Chul [School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2010-09-15

    This study was performed to examine the effects of image filter on observer performance by counting the number of holes at each wedge step on a radiographic image. An aluminum step wedge with 11 steps ranged in thickness from 1.5 mm to 16.5 mm in 1.5 mm increments was fabricated for this study. Each step had 10 notched holes with 1.0 mm diameter on the bottom of the step wedge which were ranged in depths from 0.1 mm to 1.0 mm in 0.1 mm increments. Digital radiographic raw images of the aluminum step wedge were acquired by using CCD intraoral sensor. The images were processed using several types of noise reduction filters and kernel sizes. Three observers counted the number of holes which could be discriminated on each step. The data were analyzed by ANOVA. The number of holes at each step was decreased as the thickness of step was increased. The number of holes at each step on the raw images was significantly higher than that on the processed images. The number of holes was different according to the types and kernel sizes of the image filters. The types and kernel sizes of image filters on observer performance were important, therefore, they should be standardized for commercial digital imaging systems.

  16. Analysis and Performance Comparison of DVB-T and DTMB Systems for Terrestrial Digital TV

    CERN Document Server

    Liu, Ming; Hélard, Jean-François; Pasquero, Oudomsack

    2008-01-01

    Orthogonal frequency-division multiplexing (OFDM) is the most popular transmission technology in digital terrestrial broadcasting (DTTB), adopted by many DTTB standards. In this paper, the bit error rate (BER) performance of two DTTB systems, namely cyclic prefix OFDM (CP-OFDM) based DVB-T and time domain synchronous OFDM (TDS-OFDM) based DTMB, is evaluated in different channel conditions. Spectrum utilization and power efficiency are also discussed to demonstrate the transmission overhead of both systems. Simulation results show that the performances of the two systems are much close. Given the same ratio of guard interval (GI), the DVB-T outperforms DTMB in terms of signal to noise ratio (SNR) in Gaussian and Ricean channels, while DTMB behaves better performance in Rayleigh channel in higher code rates and higher orders of constellation thanks to its efficient channel coding and interleaving scheme.

  17. Case base classification on digital mammograms: improving the performance of case base classifier

    Science.gov (United States)

    Raman, Valliappan; Then, H. H.; Sumari, Putra; Venkatesa Mohan, N.

    2011-10-01

    Breast cancer continues to be a significant public health problem in the world. Early detection is the key for improving breast cancer prognosis. The aim of the research presented here is in twofold. First stage of research involves machine learning techniques, which segments and extracts features from the mass of digital mammograms. Second level is on problem solving approach which includes classification of mass by performance based case base classifier. In this paper we build a case-based Classifier in order to diagnose mammographic images. We explain different methods and behaviors that have been added to the classifier to improve the performance of the classifier. Currently the initial Performance base Classifier with Bagging is proposed in the paper and it's been implemented and it shows an improvement in specificity and sensitivity.

  18. 数字信道化技术中ADC的性能分析%Performance Analysis of Analog-to-Digital Converters in Digital Channelization Techniques

    Institute of Scientific and Technical Information of China (English)

    马丽川; 潘亚汉; 袁方; 刘欣

    2011-01-01

    In the field of satellite communication,digital channelization techniques are used more and more widely.The analog-to-digital converter,one part of the digital channelizer,plays a great important role in the digital channelization techniques.Based on the elementary theory and performance of ADC,the effect on digital modulated signals exerted by the different number of quantization bit are discussed and simulated.%在卫星通信系统中,数字信道化技术的应用越来越广泛,而模数转换器(ADC)作为数字信道化器前端不可缺少的一部分起着至关重要的作用。基于ADC基本原理和性能,仿真分析了在ADC量化位数不同的条件下,ADC对数字已调信号解调性能的影响。

  19. The ATLAS project: The effects of a constructionist digital laboratory project on undergraduate laboratory performance.

    Science.gov (United States)

    Shoepe, Todd C; Cavedon, Dana K; Derian, Joseph M; Levy, Celine S; Morales, Amy

    2015-01-01

    Anatomical education is a dynamic field where developments in the implementation of constructive, situated-learning show promise in improving student achievement. The purpose of this study was to examine the effectiveness of an individualized, technology heavy project in promoting student performance in a combined anatomy and physiology laboratory course. Mixed-methods research was used to compare two cohorts of anatomy laboratories separated by the adoption of a new laboratory atlas project, which were defined as preceding (PRE) and following the adoption of the Anatomical Teaching and Learning Assessment Study (ATLAS; POST). The ATLAS project required the creation of a student-generated, photographic atlas via acquisition of specimen images taken with tablet technology and digital microscope cameras throughout the semester. Images were transferred to laptops, digitally labeled and photo edited weekly, and compiled into a digital book using Internet publishing freeware for final project submission. An analysis of covariance confirmed that student final examination scores were improved (P atlas project (PRE, n = 75; POST, n = 90; means ± SE; 74.9 ± 0.9 versus 78.1 ± 0.8, respectively) after controlling for cumulative student grade point average. Analysis of questionnaires collected (n = 68) from the post group suggested students identified with atlas objectives, appreciated the comprehensive value in final examination preparation, and the constructionism involved, but recommended alterations in assignment logistics and the format of the final version. Constructionist, comprehensive term-projects utilizing student-preferred technologies could be used to improve performance toward student learning outcomes. © 2014 American Association of Anatomists.

  20. Tracking Performance Analysis and Simulation of the Digital Pointing System for the Optical Communication Demonstrator

    Science.gov (United States)

    Racho, C.; Portillo, A.

    1998-10-01

    Over the past 3 years, JPL has been heavily engaged in designing and developing a reduced-complexity optical communication terminal for high-data-volume applications. The terminal is called the Optical Communication Demonstrator (OCD) and has the ability to point microradian-level beams with a very small number of detectors and steering elements. Using only a single steering mirror and a charge-coupled device (CCD) detector array, the OCD can accomplish the functions of beacon signal acquisition, beacon tracking, transmit and receive beam coalignment, and transmit beam point-ahead offset. At a higher system level, developing an understanding of the OCD performance is an essential part of achieving a better understanding of the end-to-end optical communication system performance in the field. During the latter half of fiscal year 1998, a series of experiments was conducted between Table Mountain and Strawberry Peak using the OCD as a transmitting terminal for terrestrial ground-to- ground optical link demonstrations. The OCD was taken to Strawberry Peak and set up to receive the multibeam laser beacon from the 0.6-meter telescope located at Table Mountain, a distance of approximately 40 kilometers. In the presence of atmospheric effects, the laser beacon will fluctuate both in intensity and position. The ability to determine the performance of the control loop under atmospheric-induced fades and distortion becomes very important in evaluating the results of the field testing. This article describes the design and performance of the OCD digital control loop system, which includes the steering mirror, the CCD detector array tracker, and the associated electronics. The digital control loop performance is a key factor in the ultimate performance of the laser beacon acquisition and tracking algorithm of the OCD. A model of the OCD digital control loop is developed for use in simulations. The analytical results from control loop simulations are compared with measured data

  1. Sloan Digital Sky Survey: Performance and Lessons Learned from the First Two Years of Operations

    Science.gov (United States)

    Boroski, William N.; Gunn, James E.; Kron, Richard G.; Peoples, John, Jr.

    2002-12-01

    Over a 5-year observing period, the Sloan Digital Sky Survey (SDSS) will acquire data to construct a digital 5-color photometric map of the Northern Galactic sky to about 23rd magnitude, and a correspondingly large and homogeneous spectroscopic survey. The SDSS is in a unique class of projects, in that all aspects of the SDSS infrastructure, from the telescopes and instruments, to software and operations staffing, were designed and assembled specifically to conduct this Survey. To ensure success, observing operations are run in production mode and performance metrics are used to measure progress over time. The methodology of preparing the performance baseline plan, and an assessment of Survey progress after two full years of operation, are reviewed and some lessons learned discussed. In particular, the SDSS has benefited greatly by asking peers in the field to participate in external reviews that periodically assess performance and offer independent, fresh views of potential areas of concerns. Additionally, difficulties caused by the absence of an experienced systems-engineering staff during the final phase of construction and commissioning are reviewed. The challenges of building a production machine out of complex and state-of-the-art sub-systems cannot be overstated. In the case of the SDSS, insufficient systems engineering led to problems meeting initial image quality requirements, primarily because of problems with the thermal performance of the telescope and its environment. A concerted campaign to deal with these issues was successful, but that success came rather later than we would have liked. The improvements made to address the situation, and the resulting increase in operational performance, are discussed.

  2. An adaptive toolkit for image quality evaluation in system performance test of digital breast tomosynthesis

    Science.gov (United States)

    Zhang, Guozhi; Petrov, Dimitar; Marshall, Nicholas; Bosmans, Hilde

    2017-03-01

    Digital breast tomosynthesis (DBT) is a relatively new diagnostic imaging modality for women. Currently, various models of DBT systems are available on the market and the number of installations is rapidly increasing. EUREF, the European Reference Organization for Quality Assured Breast Screening and Diagnostic Services, has proposed a preliminary Guideline - protocol for the quality control of the physical and technical aspects of digital breast tomosynthesis systems, with an ultimate aim of providing limiting values guaranteeing proper performance for different applications of DBT. In this work, we introduce an adaptive toolkit developed in accordance with this guideline to facilitate the process of image quality evaluation in DBT performance test. This toolkit implements robust algorithms to quantify various technical parameters of DBT images and provides a convenient user interface in practice. Each test is built into a separate module with configurations set corresponding to the European guideline, which can be easily adapted to different settings and extended with additional tests. This toolkit largely improves the efficiency for image quality evaluation of DBT. It is also going to evolve with the development of protocols in quality control of DBT systems.

  3. A high-performance MUX-direct digital frequency synthesizer with quarter ROMs

    Institute of Scientific and Technical Information of China (English)

    Hao Zhikun; Zhang Qiang; Ni Weining; Shi Yin

    2012-01-01

    This paper presents a detailed description of a high-performance direct digital frequency synthesizer (DDFS) using optimized quarter ROMs.To improve the working frequency and spectral purity,an original quarter ROMs structure in 0.13 μm CMOS is brought forward and implemented.The working frequency is increased by 40% compared with Yuan Ling's method[1] of implementing a segmented DAC based DDFS.It has been implemented in 0.13 μm CMOS technology.The DDFS has a resolution of 10 bits with a measured SFDR 54 dBc.Its maximum operating frequency is 1.2 GHz by using six pipelining stages.Analytical investigation of improving spectral performances by using dual-slope approximation and pipeline is also presented.

  4. A novel approach to improve digital signal performance by placement and routing with manual intervention

    Science.gov (United States)

    Cheng, Guimei; Wu, Songbo; Wan, Min; Bao, Bin; Duan, Jing

    2015-04-01

    This paper describes how placement and routing with manual intervention to improve the digital signal performance. According to studying and analyzing the features of Field Programmable Gate Array (FPGA) devices which include chip architecture and timing characteristics, a new approach is presented that some key logic modules can be relocated reasonably with manual intervention after completing successful place-and-route automatically. An example is given to illustrate this method. In this example, in order to improve remote sensing Charge Coupled Device (CCD) camera performance, signal-skew and delays among CCD driving timing signals must be controlled accurately and easily. This method can make CCD driving timing signals obtain the zero-skew which means tCO (clock to out) values for all these signals are equal, and finally hardware tests are carried out and experiment results are measured precisely by oscilloscope.

  5. Performance analysis of reversible image compression techniques for high-resolution digital teleradiology.

    Science.gov (United States)

    Kuduvalli, G R; Rangayyan, R M

    1992-01-01

    The performances of a number of block-based, reversible, compression algorithms suitable for compression of very-large-format images (4096x4096 pixels or more) are compared to that of a novel two-dimensional linear predictive coder developed by extending the multichannel version of the Burg algorithm to two dimensions. The compression schemes implemented are: Huffman coding, Lempel-Ziv coding, arithmetic coding, two-dimensional linear predictive coding (in addition to the aforementioned one), transform coding using discrete Fourier-, discrete cosine-, and discrete Walsh transforms, linear interpolative coding, and combinations thereof. The performances of these coding techniques for a few mammograms and chest radiographs digitized to sizes up to 4096x4096 10 b pixels are discussed. Compression from 10 b to 2.5-3.0 b/pixel on these images has been achieved without any loss of information. The modified multichannel linear predictor outperforms the other methods while offering certain advantages in implementation.

  6. Digit ratio (2D:4D), lateral preferences, and performance in fencing.

    Science.gov (United States)

    Voracek, Martin; Reimer, Barbara; Ertl, Clara; Dressler, Stefan G

    2006-10-01

    The second to fourth digit ratio (2D:4D) is a sexually dimorphic trait (men tend to have lower values than women) and a likely biomarker for the organizational (permanent) effects of prenatal androgens on the human brain and body. Prenatal testosterone, as reflected by 2D:4D, has many extragenital effects, including its relevance for the formation of an efficient cardiovascular system. Previous research, reviewed here, has therefore investigated possible associations of 2D:4D with sport performance. Several studies found more masculinized digit ratio patterns (low 2D:4D values or a negative right-minus-left difference in 2D:4D) to be related to high performance in running, soccer, and skiing. The present research tested this hypothesis in a sample of 54 tournament fencers, predominantly from Austria. For men, negative right-left differences in 2D:4D corresponded significantly to better current as well as highest national fencing rankings, independent of training intensity and fencing experience. The mean 2D:4D values of these fencers were significantly lower and the proportion of left-handers was elevated relative to the local general population. For the right hand, the ratio was somewhat lower in male sabre fencers than in male epée and foil fencers combined and significantly lower in left-handed compared to right-handed fencers. Although nonsignificant due to low statistical power, effect sizes suggested that crossed versus congruent hand-eye and hand-foot preferences might also be related to fencing performance. The present findings add to the evidence that 2D:4D might be a performance indicator for men across a variety of sports.

  7. The effect of pitch, rhythm, and familiarity on working memory and anxiety as measured by digit recall performance.

    Science.gov (United States)

    Silverman, Michael J

    2010-01-01

    The purpose of this study was to isolate and quantitatively evaluate the effects of pitch and rhythm of unfamiliar and familiar melodies on working memory and anxiety as measured by sequential digit recall performance. Participants (N = 60) listened to 6 treatment conditions each consisting of 9 randomized monosyllabic digits. The digits were paired with (a) a familiar melody and pitch only, (b) a familiar melody and rhythm only, (c) a familiar melody with both pitch and rhythm, (d) an unfamiliar melody with pitch only, (e) an unfamiliar melody with rhythm only, and (f) an unfamiliar melody with both pitch and rhythm. The 6 different treatments were counterbalanced using a Latin square design in an attempt to control for order effects. Participants rated their state anxiety on a Likert-type scale before, midway through, and after the digits test. No statistically significant order, learning, or practice effects were found. A 3-way repeated-measures ANOVA indicated a statistically significant difference in digit recall performance across musical element conditions and groups. Results indicated that music majors outperformed nonmusic majors on the digit recall task. Participants were able to recall digits from the rhythm condition most accurately while recalling digits from pitch only and both pitch and rhythm conditions the least accurately. Graphic analysis of treatment as a function of sequential position indicated digit recall was best during conditions of primacy and recency. No main effects were found for the familiarity condition. Additionally, no main effects or interactions were found for the anxiety variable. The results of this study are congruent with existing working memory and music literature suggesting that pairing information with rhythm can facilitate recall, music majors outperform non-music majors, and recall accuracy is best in positions of primacy and recency. Implications for practice in therapy and education are made as well as suggestions for

  8. Set-up and preliminary performance of a digital radiology conference system

    Institute of Scientific and Technical Information of China (English)

    王学建; 胡建; 曹军; 王波; 焦俊; 魏渝清; 王小林; 罗敏; 罗松

    2003-01-01

    Objective To investigate the set-up and preliminary performance of a digital radiology conference system and its characteristics. Methods The imaging system included a dual-screen image-text workstation with a Matrox G450 demonstration dual-head card, two multimedia projectors, a large screen, and a line-pair and grey scale test card. Patient information on radiology information system (RIS) and images on picture archiving and communication system (PACS) were fetched with GE Radworks software based on Intranet and PACS. The fetching velocity and resolution and grey scale of the images were measured. Results Patient information in the form of texts and images were demonstrated successfully on two screens with Matrox G450 demonstration dual-head card and switched rapidly between text-image two-screen and image two-screen. The image fetching velocity was fast, the resolution was high, and the grey scale was good. Conclusion The digital conference radiology system is good, and should be popularized.

  9. A high-performance, low-power {sigma} {Delta} ADC for digital audio applications

    Energy Technology Data Exchange (ETDEWEB)

    Luo Hao; Han Yan; Han Xiaoxia; Ma Shaoyu; Ying Peng; Zhu Dazhong [Institute of Microelectronics and Photoelectronics, Zhejiang University, Hangzhou 310027 (China); Cheung, Ray C. C., E-mail: hany@zju.edu.c [Department of Electronic Engineering, City University of Hong Kong, Hong Kong 999077 (China)

    2010-05-15

    A high-performance low-power {sigma} {Delta} analog-to-digital converter (ADC) for digital audio applications is described. It consists of a 2-1 cascaded {sigma} {Delta} modulator and a decimation filter. Various design optimizations are implemented in the system design, circuit implementation and layout design, including a high-overload-level coefficient-optimized modulator architecture, a power-efficient class A/AB operational transconductance amplifier, as well as a multi-stage decimation filter conserving area and power consumption. The ADC is implemented in the SMIC 0.18-{mu}m CMOS mixed-signal process. The experimental chip achieves a peak signal-to-noise-plus-distortion ratio of 90 dB and a dynamic range of 94 dB over 22.05-kHz audio band and occupies 2.1 mm{sup 2}, which dissipates only 2.1 mA quiescent current in the analog circuits. (semiconductor integrated circuits)

  10. Digital Devices, Distraction and Student Performance - Does Cell Phone Use Reduce Learning?

    Science.gov (United States)

    Duncan, Douglas K.; Hoekstra, A. R.; Wilcox, B. R.

    2012-01-01

    The recent increase in the use of digital devices such as laptop computers, iPads and web-enabled cell phones has generated concern about how technologies affect student performance. Combining observation, survey, and interview data, this research assesses the effects of technology use for student attitudes and learning. Data were gathered in eight introductory science courses at one large public university in 2010-2011. Results show a significant negative correlation between in-class cell phone use and overall course grades, corresponding to a drop of 0.36 ± 0.08 on a 4-point scale where 4.0 = A. These findings are consistent with recent research[1] suggesting students cannot multi-task nearly as effectively as they think they can. While 75% of students reported regular cell phone use, observation data suggests undergraduates typically under-report the frequency of in-class digital device use. [1] Ophir, E., Nass, C. and A.D. Wagner. 2009. "Cognitive Control in Media Multi-Taskers.” Proceedings of the National Academy of Sciences, 106: 15583-15587.

  11. Effects of rapid digitalization on total and regional myocardial performance in patients with coronary artery disease.

    Science.gov (United States)

    Ferlinz, J; DelVicario, M; Aronow, W S

    1978-09-01

    In order to evaluate the effects of rapid digitalization on LV volumes, ejection fraction, and asynergy, 21 patients without heart failure were studied with a combination of hemodynamic and angiographic techniques before and after administration of intravenous ouabain (0.007 mg./Kg.). Seven patients had no CAD and served as normal (control) subjects (Group I), while 14 patients had extensive coronary disease (Group II). All pre-ouabain parameters were within the normal limits in Group I. After ouabain infusion, all indices of LV contractility: dP/dt, VCF, and ejection fraction rose significantly in the normal group, while LV filling pressure and end-diastolic volume remained unchanged. The baseline hemodynamic and volumetric values for Group II patients corresponded closely to their normal (Group I) counterparts, and exhibited similar changes after ouabain administration. Eight patients in Group II also had regional disorders of LV contractility, delineated by 23 abnormal hemiaxes of shortening. After ouabain, 15 out of 23 asynergic segments (65 per cent) improved, seven remained unchanged, and one worsened. It is therefore concluded that rapid digitalization not only enhances LV performance in normal subjects and in patients with CAD, but can also markedly reduce the extent of LV asynergy.

  12. Digital audio broadcasting: Measuring techniques and coverage performance for a medium power VHF single frequency network

    Science.gov (United States)

    Maddocks, M. C. D.; Eng, C.; Pullen, I. R.; Green, J. A.

    1995-02-01

    The advent of digital formats such as CD has created demand for uniformly high audio quality from radio. In order to provide such high-quality stereo reception, a Digital Audio Broadcasting (DAB) system capable of reliable reception in vehicles and on portables has been developed by the European EUREKA 147 Project. As a VHF frequency allocation would appear most suitable for the introduction of terrestrial broadcasting of DAB in the United Kingdom, the BBC is undertaking a major experiment to test the EUREKA DAB system and to generate data to allow efficient planning of its transmitter network. A network of four, 1 kW e.r.p., VHF transmitters has been installed to cover the London area in England. This Report describes the experimental program and the rationale and measurement techniques behind it. The results show a wide-area coverage from the transmitter network which is in reasonable agreement with computer predictions. This indicates that the current transmitting and receiving equipment (built to the EUREKA specification) is operating in the way that would be expected from theoretical studies and simulation. The results also provide quantitative values which can be used for coverage prediction and for international co-ordination of services. Finally, the performance of the system demonstrates a number of the benefits of the EUREKA DAB system for mobile and portable reception.

  13. Performance evaluation of intensity modulated optical OFDM system with digital baseband distortion.

    Science.gov (United States)

    Vanin, Evgeny

    2011-02-28

    Bit-Error-Ratio (BER) of intensity modulated optical orthogonal frequency division multiplexing (OFDM) system is analytically evaluated accounting for nonlinear digital baseband distortion in the transmitter and additive noise in the photo receiver. The nonlinear distortion that is caused by signal clipping and quantization is taken into consideration. The signal clipping helps to overcome the system performance limitation related to high peak-to-average power ratio (PAPR) of the OFDM signal and to minimize the value of optical power that is required for achieving specified BER. The signal quantization due to a limited bit resolution of the digital to analog converter (DAC) causes an optical power penalty in the case when the bit resolution is too low. By introducing an effective signal to noise ratio (SNR) the optimum signal clipping ratio, system BER and required optical power at the input to the receiver is evaluated for the OFDM system with multi-level quadrature amplitude modulation (QAM) applied to the optical signal subcarriers. Minimum required DAC bit resolution versus the size of QAM constellation is identified. It is demonstrated that the bit resolution of 7 and higher causes negligibly small optical power penalty at the system BER=10⁻³ when 256-QAM and a constellation of lower size is applied. The performance of the optical OFDM system is compared to the performance of the multi-level amplitude-shift keying (M-ASK) system for the same number of information bits transmitted per signal sample. It is demonstrated that in the case of the matched receiver the M-ASK system outperforms OFDM and requires 3-3.5 dB less of optical power at BER=10⁻³ when 1-4 data bits are transmitted per signal sample.

  14. The Effect of Format on Performance: Editing Text in Print versus Digital Formats

    Science.gov (United States)

    Eden, Sigal; Eshet-Alkalai, Yoram

    2013-01-01

    In light of the present-day proliferation of digital texts and the increase in situations that require active digital text reading in learning, it is becoming increasingly important to shed light on the comparison between print and digital reading under active reading conditions. In this study, the active reading abilities of 93 university…

  15. A Program Based on English Digital Stories to Develop the Writing Performance and Reflective Thinking of Preparatory School Pupils

    Science.gov (United States)

    Hassan Seifeddin, Ahmed; Zakareya Ahmed, Samah; Yahia Mohammed Ebrahim, Eman

    2015-01-01

    This study aimed to investigate the effect of a program based on English digital stories on second-year preparatory pupils' writing performance and reflective thinking. Two writing performance tests (pretest and posttest) as well as a reflective thinking test were prepared by the researchers. Two 2nd-year intact classes from El Sadat Prep School…

  16. Design and Performance of a Custom ASIC Digitizer for Wire Chamber Readout in 65 nm CMOS Technology

    CERN Document Server

    Lee, MyeongJae; Chang, Jessica K; Ding, Dawei; Gnani, Dario; Grace, Carl R; Jones, John A; Kolomensky, Yury G; von der Lippe, Henrik; Mcvittie, Patrick J; Stettler, Matthew W; Walder, Jean-Pierre

    2015-01-01

    We present the design and performance of a prototype ASIC digitizer for integrated wire chamber readout, implemented in 65 nm commercial CMOS technology. Each channel of the 4-channel prototype is composed of two 16-bit Time-to-Digital Converters (TDCs), one 8-bit Analog-to-Digital Converter (ADC), a front-end preamplifier and shaper, plus digital and analog buffers that support a variety of digitization chains. The prototype has a multiplexed digital backend that executes a state machine, distributes control and timing signals, and buffers data for serial output. Laboratory bench tests measure the absolute TDC resolution between 74 ps and 480 ps, growing with the absolute delay, and a relative time resolution of 19 ps. Resolution outliers due to cross-talk between clock signals and supply or reference voltages are seen. After calibration, the ADC displays good linearity and noise performance, with an effective number of bits of 6.9. Under normal operating conditions the circuit consumes 32 mW per channel. Po...

  17. Design and performance of a custom ASIC digitizer for wire chamber readout in 65 nm CMOS technology

    Science.gov (United States)

    Lee, M. J.; Brown, D. N.; Chang, J. K.; Ding, D.; Gnani, D.; Grace, C. R.; Jones, J. A.; Kolomensky, Y. G.; von der Lippe, H.; Mcvittie, P. J.; Stettler, M. W.; Walder, J.-P.

    2015-06-01

    We present the design and performance of a prototype ASIC digitizer for integrated wire chamber readout, implemented in 65 nm commercial CMOS technology. Each channel of the 4-channel prototype is composed of two 16-bit Time-to-Digital Converters (TDCs), one 8-bit Analog-to-Digital Converter (ADC), a front-end preamplifier and shaper, plus digital and analog buffers that support a variety of digitization chains. The prototype has a multiplexed digital backend that executes a state machine, distributes control and timing signals, and buffers data for serial output. Laboratory bench tests measure the absolute TDC resolution between 74 ps and 480 ps, growing with the absolute delay, and a relative time resolution of 19 ps. Resolution outliers due to cross-talk between clock signals and supply or reference voltages are seen. After calibration, the ADC displays good linearity and noise performance, with an effective number of bits of 6.9. Under normal operating conditions the circuit consumes 32 mW per channel. Potential design improvements to address the resolution drift and tails are discussed.

  18. The european FAZIA initiative: a high-performance digital telescope array for heavy-ion studies

    CERN Document Server

    Casini, G; Pasquali, G; Pastore, G; Bini, M; Carboni, S; Olmi, A; Piantelli, S; Poggi, G; Stefanini, A; Valdre', S; Bonnet, E; Borderie, B; Bougault, R; Bruno, M; Chbihi, A; Cinausero, M; Degerlier, M; Edelbruck, P; Frankland, J D; Gramegna, F; Gruyer, D; Guerzoni, M; Kordjasz, A; Kozik, T; Neindre, N Le; Lopez, O; Marchi, T; Marini, P; Morelli, L; Ordine, A; Parlog, M; Rivet, M F; Rosato, E; Salomon, F; Spadaccini, G; Twarog, T; Vient, E; Vigilante, M

    2013-01-01

    The european Fazia collaboration aims at building a new modular array for charged product identification to be employed for heavy-ion studies. The elementary module of the array is a Silicon-Silicon-CsI telescope, optimized for ion identification also via pulse shape analysis. The achievement of top performances imposes specific electronics which has been developed by FAZIA and features high quality charge and current preamplifiers, coupled to fully digital front-end. During the initial R&D phase, original and novel solutions have been tested in prototypes, obtaining unprecedented ion identification capabilities. FAZIA is now constructing a demonstrator array consisting of about two hundreds telescopes arranged in a compact and transportable configuration. In this contribution, we mainly summarize some aspects studied by FAZIA to improve the ion identification. Then we will briefly discuss the FAZIA program centered on experiments to be done with the demonstrator. First results on the isospin dynamics obt...

  19. PERFORMANCE IMPROVEMENT FOR A WCDMA RADIO OVER FIBER SYSTEM USING DIGITAL PRE-DISTORTER

    Institute of Scientific and Technical Information of China (English)

    Ying Xiangyue; Xu Tiefeng; Liu Taijun; Nie Qiuhua

    2012-01-01

    In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously suppressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is obtained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in linearization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.

  20. Performance Analysis on Throughput in 4G Network in Digital Environment with SISO Technique

    Directory of Open Access Journals (Sweden)

    Nausrat Jahan Ahmed

    2013-06-01

    Full Text Available The development of the 4G or the Long Term Evolution (LTE is working at a very fast pace. The 4G system invention had very high prospective and goals compared to 3G. It was already thought that the system should be more competitive and secure based. Every wireless connection would be IP oriented. 4G is on its phase in improving the Quality of Service (QOS. This paper shows the comparison of the throughput delivered by the different modulation techniques which have been proposed to be used. Also comparison has been made with the different Extended Channel Models. Figures and graphs have been put forward to show the performance by the throughput delivered in digital environment and RF technology.

  1. Digital holographic PTV analysis of the motile performance of the red-tides alga ``Cochlodinium polykrikoides''

    Science.gov (United States)

    Sohn, M.; Lee, S.; Choi, Y.; Seo, G.; Kang, Y.; Kang, Y.

    2009-11-01

    The outbreaks of Cochlodinium polykrikoides causes severe damages to fisheries in Korea and Japan. C. polykrikoides actively makes chains in its exponential and stationary growth phase. The role of the chain formation has not been clearly known yet. In the present study, the motility characteristics of C. polykrikoides was investigated using 3D digital holographic PTV technique. The moving trajectories and average velocities of the single and multi-chained C. polykrikoides were compared to investigate the effect of the chain formation on the motile performance. Most of the multi-chained C. polykrikoides exhibited zigzag or helical trajectory and the translational velocity of the 4-chained C. polykrikoides was at least two-times larger than the single one.

  2. Performance improvements of a highly integrated digital electronic control system for an F-15 airplane

    Science.gov (United States)

    Putnam, T. W.; Burcham, F. W., Jr.; Andries, M. G.; Kelly, J. B.

    1985-01-01

    The NASA highly integrated digital electronic control (HIDEC) program is structured to conduct flight research into the benefits of integrating an aircraft flight control system with the engine control system. A brief description of the HIDEC system installed on an F-15 aircraft is provided. The adaptive engine control system (ADECS) mode is described in detail, together with simulation results and analyses that show the significant excess thrust improvements achievable with the ADECS mode. It was found that this increased thrust capability is accompanied by reduced fan stall margin and can be realized during flight conditions where engine face distortion is low. The results of analyses and simulations also show that engine thrust response is improved and that fuel consumption can be reduced. Although the performance benefits that accrue because of airframe and engine control integration are being demonstrated on an F-15 aircraft, the principles are applicable to advanced aircraft such as the advanced tactical fighter and advanced tactical aircraft.

  3. On the Performance Analysis of Digital Communications over Weibull-Gamma Channels

    KAUST Repository

    Ansari, Imran Shafique

    2015-05-01

    In this work, the performance analysis of digital communications over a composite Weibull-Gamma (WG) multipath-fading and shadowing channel is presented wherein WG distribution is appropriate for modeling fading environments when multipath is superimposed on shadowing. More specifically, in this work, exact closed-form expressions are derived for the probability density function, the cumulative distribution function, the moment generating function, and the moments of a composite WG channel. Capitalizing on these results, new exact closed-form expressions are offered for the outage probability, the higher- order amount of fading, the average error rate for binary and M-ary modulation schemes, and the ergodic capacity under various types of transmission policies, mostly in terms of Meijer\\'s G functions. These new analytical results were also verified via computer-based Monte-Carlo simulation results. © 2015 IEEE.

  4. Digital imaging and remote sensing image generator (DIRSIG) as applied to NVESD sensor performance modeling

    Science.gov (United States)

    Kolb, Kimberly E.; Choi, Hee-sue S.; Kaur, Balvinder; Olson, Jeffrey T.; Hill, Clayton F.; Hutchinson, James A.

    2016-05-01

    The US Army's Communications Electronics Research, Development and Engineering Center (CERDEC) Night Vision and Electronic Sensors Directorate (referred to as NVESD) is developing a virtual detection, recognition, and identification (DRI) testing methodology using simulated imagery as a means of augmenting the field testing component of sensor performance evaluation, which is expensive, resource intensive, time consuming, and limited to the available target(s) and existing atmospheric visibility and environmental conditions at the time of testing. Existing simulation capabilities such as the Digital Imaging Remote Sensing Image Generator (DIRSIG) and NVESD's Integrated Performance Model Image Generator (NVIPM-IG) can be combined with existing detection algorithms to reduce cost/time, minimize testing risk, and allow virtual/simulated testing using full spectral and thermal object signatures, as well as those collected in the field. NVESD has developed an end-to-end capability to demonstrate the feasibility of this approach. Simple detection algorithms have been used on the degraded images generated by NVIPM-IG to determine the relative performance of the algorithms on both DIRSIG-simulated and collected images. Evaluating the degree to which the algorithm performance agrees between simulated versus field collected imagery is the first step in validating the simulated imagery procedure.

  5. The effects of gray scale image processing on digital mammography interpretation performance.

    Science.gov (United States)

    Cole, Elodia B; Pisano, Etta D; Zeng, Donglin; Muller, Keith; Aylward, Stephen R; Park, Sungwook; Kuzmiak, Cherie; Koomen, Marcia; Pavic, Dag; Walsh, Ruth; Baker, Jay; Gimenez, Edgardo I; Freimanis, Rita

    2005-05-01

    To determine the effects of three image-processing algorithms on diagnostic accuracy of digital mammography in comparison with conventional screen-film mammography. A total of 201 cases consisting of nonprocessed soft copy versions of the digital mammograms acquired from GE, Fischer, and Trex digital mammography systems (1997-1999) and conventional screen-film mammograms of the same patients were interpreted by nine radiologists. The raw digital data were processed with each of three different image-processing algorithms creating three presentations-manufacturer's default (applied and laser printed to film by each of the manufacturers), MUSICA, and PLAHE-were presented in soft copy display. There were three radiologists per presentation. Area under the receiver operating characteristic curve for GE digital mass cases was worse than screen-film for all digital presentations. The area under the receiver operating characteristic for Trex digital mass cases was better, but only with images processed with the manufacturer's default algorithm. Sensitivity for GE digital mass cases was worse than screen film for all digital presentations. Specificity for Fischer digital calcifications cases was worse than screen film for images processed in default and PLAHE algorithms. Specificity for Trex digital calcifications cases was worse than screen film for images processed with MUSICA. Specific image-processing algorithms may be necessary for optimal presentation for interpretation based on machine and lesion type.

  6. Discrepancies between bilinguals' performance on the Spanish and English versions of the WAIS Digit Span task: Cross-cultural implications.

    Science.gov (United States)

    López, Enrique; Steiner, Alexander J; Hardy, David J; IsHak, Waguih W; Anderson, W Brantley

    2016-01-01

    This study explored within-subjects differences in the performance of 40 bilingual participants on the English and Spanish versions of the Wechsler Adult Intelligence Scale (WAIS) Digit Span task. To test the linguistic hypothesis that individuals would perform worse in Spanish because of its syllabic demand, we compared the number of syllables correctly recalled by each participant for every correct trial. Our analysis of the correct number of syllables remembered per trial showed that participants performed significantly better (i.e., recalling more syllables) in Spanish than in English on the total score. Findings suggest the Spanish version of the Digit Span (total score) was significantly more difficult than the English version utilizing traditional scoring methods. Moreover, the Forward Trial, rather than the Backward Trial, was more likely to show group differences between both language versions. Additionally, the Spanish trials of the Digit Span were correlated with language comprehension and verbal episodic memory measures, whereas the English trials of the Digit Span were correlated with confrontational naming and verbal fluency tasks. The results suggest that more research is necessary to further investigate other cognitive factors, rather than just syllabic demand, that might contribute to performance and outcome differences on the WAIS Digit Span in Spanish-English bilinguals.

  7. Does Reader Performance with Digital Breast Tomosynthesis Vary according to Experience with Two-dimensional Mammography?

    Science.gov (United States)

    Tucker, Lorraine; Gilbert, Fiona J; Astley, Susan M; Dibden, Amanda; Seth, Archana; Morel, Juliet; Bundred, Sara; Litherland, Janet; Klassen, Herman; Lip, Gerald; Purushothaman, Hema; Dobson, Hilary M; McClure, Linda; Skippage, Philippa; Stoner, Katherine; Kissin, Caroline; Beetles, Ursula; Lim, Yit Yoong; Hurley, Emma; Goligher, Jane; Rahim, Rumana; Gagliardi, Tanja J; Suaris, Tamara; Duffy, Stephen W

    2017-05-01

    Purpose To assess whether individual reader performance with digital breast tomosynthesis (DBT) and two-dimensional (2D) mammography varies with number of years of experience or volume of 2D mammograms read. Materials and Methods After written informed consent was obtained, 8869 women (age range, 29-85 years; mean age, 56 years) were recruited into the TOMMY trial (A Comparison of Tomosynthesis with Digital Mammography in the UK National Health Service Breast Screening Program), an ethically approved, multicenter, multireader, retrospective reading study, between July 2011 and March 2013. Each case was read prospectively for clinical assessment and to establish ground truth. A retrospective reading data set of 7060 cases was created and randomly allocated for independent blinded review of (a) 2D mammograms, (b) DBT images and 2D mammograms, and (c) synthetic 2D mammograms and DBT images, without access to previous examinations. Readers (19 radiologists, three advanced practitioner radiographers, and two breast clinicians) who had 3-25 (median, 10) years of experience in the U.K. National Health Service Breast Screening Program and read 5000-13 000 (median, 8000) cases per annum were included in this study. Specificity was analyzed according to reader type and years and volume of experience, and then both specificity and sensitivity were analyzed by matched inference. The median duration of experience (10 years) was used as the cutoff point for comparison of reader performance. Results Specificity improved with the addition of DBT for all readers. This was significant for all staff groups (56% vs 68% and 49% vs 67% [P readers and was significantly higher for those with less than 10 years of experience (91% vs 86%; P = .03) and those with total mammographic experience of fewer than 80 000 cases (88% vs 86%; P = .03). Conclusion The addition of DBT to conventional 2D screening mammography improved specificity for all readers, but the gain in sensitivity was greater

  8. Cortical areas related to performance of WAIS Digit Symbol Test: a functional imaging study.

    Science.gov (United States)

    Usui, Nobuo; Haji, Tomoki; Maruyama, Masakazu; Katsuyama, Narumi; Uchida, Shinya; Hozawa, Atsushi; Omori, Kahoru; Tsuji, Ichiro; Kawashima, Ryuta; Taira, Masato

    2009-09-29

    Many neuropsychological studies have shown that the Digit Symbol Test (DST) of the Wechsler Adult Intelligence Scale (WAIS) is useful for screening for dysfunctions of the brain. However, it remains unclear which brain areas are actually involved in the performance of DST and what brain functions are used for executing this test. In this study, we examined the cortical areas related to cognitive aspects of DST using functional magnetic resonance imaging (fMRI) and determined executive brain functions involved in this test on the basis of fMRI results. Eleven healthy young adults (mean=21.6 years) performed a modified DST (mDST) task and its control task, which required a simple graphomotor response during fMRI data acquisition. The direct comparison of brain activations between the mDST task and the control task revealed greater activations in a fronto-parietal cortical network, including the bilateral inferior frontal sulci, left middle frontal gyrus (close to the frontal eye field) and left posterior parietal cortex. These activations are interpreted as reflecting the visual search process and/or the updating process of working memory during the mDST task execution. Furthermore, we found a positive correlation between the number of correct responses and activations in the bilateral inferior frontal regions, suggesting that these prefrontal areas have a crucial role in the performance of DST in a healthy young adult population.

  9. Standard practice for digital detector array performance evaluation and long-term stability

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice describes the evaluation of DDA systems for industrial radiology. It is intended to ensure that the evaluation of image quality, as far as this is influenced by the DDA system, meets the needs of users, and their customers, and enables process control and long term stability of the DDA system. 1.2 This practice specifies the fundamental parameters of Digital Detector Array (DDA) systems to be measured to determine baseline performance, and to track the long term stability of the DDA system. 1.3 The DDA system performance tests specified in this practice shall be completed upon acceptance of the system from the manufacturer and at intervals specified in this practice to monitor long term stability of the system. The intent of these tests is to monitor the system performance for degradation and to identify when an action needs to be taken when the system degrades by a certain level. 1.4 The use of the gages provided in this standard is mandatory for each test. In the event these tests or ga...

  10. The New Global Digital Elevation Model : TanDEM-X DEM and its Final Performance

    Science.gov (United States)

    Gonzalez, Carolina; Rizzoli, Paola; Martone, Michele; Wecklich, Christopher; Borla Tridon, Daniela; Bachmann, Markus; Fritz, Thomas; Wessel, Birgit; Krieger, Gerhard; Zink, Manfred

    2017-04-01

    Digital elevation models (DEMs) have become widely used in many scientific and commercial applications and there are several local products have been developed in the last years. They provide a representation of the topographic features of the landscape. The importance of them is known and valued in every geoscience field, but they have also vast use in navigation and in other commercial areas. The main goal of the TanDEM-X (TerraSARX add-on for Digital Elevation Measurements) mission is the generation of a global DEM, homogeneous in quality with unprecedented global accuracy and resolution, which has been completed in mid-2016. For over four years, the almost identical satellites TerraSAR-X and TanDEM-X acquired single-pass interferometric SAR image pairs, from which is it possible to derive the topographic height by unwrapping the interferometric phase, unaffected by temporal decorrelation. Both satellites have been flying in close formation with a flexible geometric configuration. An optimized acquisition strategy aimed at achieving an absolute vertical accuracy much better than 10 meters and a relative vertical accuracy of 2 m and 4 m for flat and steep terrain, respectively, within a horizontal raster of 12 m x 12 m, which slightly varies depending on the geographic latitude. In this paper, we assess the performance of the global Tandem-X DEM, characterized in terms of relative and absolute vertical accuracy. The coverage statistics are also discussed in comparison to the previous almost global but with lower resolution DEM provided by the Shuttle Radar Topography Mission (SRTM). The exceptional quality of the global DEM is confirmed by the obtained results and the global TanDEM-X DEM is now ready to be distributed to the scientific and commercial community.

  11. Performance of quasi-optimum digital FM demodulators for fading channels

    Science.gov (United States)

    Dharamsi, M. T.; Gupta, S. C.

    1975-01-01

    This paper deals with the problem of digital demodulation of FM signals transmitted over Rayleigh and Rician fading channels. The Rayleigh and Rician fading channels are represented by two quadrature multiplicative nonzero mean white Gaussian processes in addition to an additive zero-mean white Gaussian noise. Quasi-optimum digital baseband demodulation algorithms using various nonlinear estimation techniques are derived. The digital demodulator structures are then simulated on a digital computer for an FM system with first order message spectrum for various values of the parameters for Rayleigh and Rician channels.

  12. Transmission Performance Analysis of Digital Wire and Wireless Optical Links in Local and Wide Areas Optical Networks

    CERN Document Server

    Mohamed, Abd El Naser A; Rashed, Ahmed Nabih Zaki; Nabawy, Amina E M El

    2009-01-01

    In the present paper, the transmission performance analysis of digital wire and wireless optical links in local and wide areas optical networks have been modeled and parametrically investigated over wide range of the affecting parameters. Moreover, we have analyzed the basic equations of the comparative study of the performance of digital fiber optic links with wire and wireless optical links. The development of optical wireless communication systems is accelerating as a high cost effective to wire fiber optic links. The optical wireless technology is used mostly in wide bandwidth data transmission applications. Finally, we have investigated the maximum transmission distance and data transmission bit rates that can be achieved within digital wire and wireless optical links for local and wide areas optical network applications.

  13. Performance Evaluation of a Non-Coherent Digital Delay-Locked Loop in Rayleigh Fading Channels

    Directory of Open Access Journals (Sweden)

    Mohamed G. El-Tarhuni

    2010-11-01

    Full Text Available PN code tracking is one of the most important factors that affect the performance of spread spectrumreceivers. It is desirable to maintain PN code tracking for a long period of time and with high accuracy.This paper presents a non-coherent digital delay-locked loop (DLL for code tracking in direct-sequencespread spectrum (DS-SS systems. The proposed technique utilizes three non-coherent correlators withtime-diversity followed by a lock detector. Analytical results for the mean time to lose lock, also calledmean hold-in time, are derived for both additive white Gaussian noise and Rayleigh fading channelsusing a Markov chain model. Computer simulation results are also presented to validate the analyticalresults. It is shown that the proposed loop can maintain lock for relatively long periods of time underpractical range of signal-to-noise ratio. For instance, the loop maintains lock for more than106 framesfor an energy per bit-to-noise power spectral density (Eb/No of 4 dB or better. It is also shown that themean hold-in time performance is only slightly degraded due to fading because of the time diversity gainutilized by the loop in obtaining the timing information. Finally, the ability of the proposed technique tosuccessfully track randomly and linearly varying delays is demonstrated.

  14. Towards a smart Holter system with high performance analogue front-end and enhanced digital processing.

    Science.gov (United States)

    Du, Leilei; Yan, Yan; Wu, Wenxian; Mei, Qiujun; Luo, Yu; Li, Yang; Wang, Lei

    2013-01-01

    Multiple-lead dynamic ECG recorders (Holter) play an important role in the earlier detection of various cardiovascular diseases. In this paper, we present the first several steps towards a 12-lead Holter system with high-performance AFE (Analogue Front-End) and enhanced digital processing. The system incorporates an analogue front-end chip (ADS1298 from TI), which has not yet been widely used in most commercial Holter products. A highly-efficient data management module was designated to handle the data exchange between the ADS1298 and the microprocessor (STM32L151 from ST electronics). Furthermore, the system employs a Field Programmable Gate Array (Spartan-3E from Xilinx) module, on which a dedicated real-time 227-step FIR filter was executed to improve the overall filtering performance, since the ADS1298 has no high-pass filtering capability and only allows limited low-pass filtering. The Spartan-3E FPGA is also capable of offering further on-board computational ability for a smarter Holter. The results indicate that all functional blocks work as intended. In the future, we will conduct clinical trials and compare our system with other state-of-the-arts.

  15. The european FAZIA initiative: a high-performance digital telescope array for heavy-ion studies

    Science.gov (United States)

    Casini, G.; Barlini, S.; Pasquali, G.; Pastore, G.; Bini, M.; Carboni, S.; Olmi, A.; Piantelli, S.; Poggi, G.; Stefanini, A.; Valdré, S.; Bonnet, E.; Borderie, B.; Bougault, R.; Bruno, M.; Chbihi, A.; Cinausero, M.; Degerlier, M.; Edelbruck, P.; Frankland, J. D.; Gramegna, F.; Gruyer, D.; Guerzoni, M.; Kordjasz, A.; Kozik, T.; Le Neindre, N.; Lopez, O.; Marchi, T.; Marini, P.; Morelli, L.; Ordine, A.; Pârlog, M.; Rivet, M. F.; Rosato, E.; Salomon, F.; Spadaccini, G.; Twaróg, T.; Vient, E.; Vigilante, M.

    2014-03-01

    The european Fazia collaboration aims at building a new modular array for charged product identification to be employed for heavy-ion studies. The elementary module of the array is a Silicon-Silicon-CsI telescope, optimized for ion identification including pulse shape analysis, too. The achievement of top performances imposes specific electronics which has been developed by the FAZIA collaboration and includes high quality charge and current preamplifiers, coupled to fully digital front-end. During the initial R&D phase, original and novel solutions have been tested in prototypes, obtaining unprecedented ion identification capabilities. FAZIA is now constructing a demonstrator array consisting of about two hundreds telescopes arranged in a compact and transportable configuration. In this contribution, we mainly summarize some aspects studied by FAZIA to improve the ion identification. Then we will briefly discuss the FAZIA program focused on experiments to be done with the demonstrator. First results on the isospin dynamics obtained with a reduced set-up demonstrate well the performance of the telescope and represent a good starting point towards future investigations with both stable and exotic beams.

  16. The european FAZIA initiative: a high-performance digital telescope array for heavy-ion studies

    Directory of Open Access Journals (Sweden)

    Casini G.

    2014-03-01

    Full Text Available The european Fazia collaboration aims at building a new modular array for charged product identification to be employed for heavy-ion studies. The elementary module of the array is a Silicon-Silicon-CsI telescope, optimized for ion identification including pulse shape analysis, too. The achievement of top performances imposes specific electronics which has been developed by the FAZIA collaboration and includes high quality charge and current preamplifiers, coupled to fully digital front-end. During the initial R&D phase, original and novel solutions have been tested in prototypes, obtaining unprecedented ion identification capabilities. FAZIA is now constructing a demonstrator array consisting of about two hundreds telescopes arranged in a compact and transportable configuration. In this contribution, we mainly summarize some aspects studied by FAZIA to improve the ion identification. Then we will briefly discuss the FAZIA program focused on experiments to be done with the demonstrator. First results on the isospin dynamics obtained with a reduced set-up demonstrate well the performance of the telescope and represent a good starting point towards future investigations with both stable and exotic beams.

  17. Using Digital Technologies to Improve the Authenticity of Performance Assessment for High-Stakes Purposes

    Science.gov (United States)

    Newhouse, C. Paul

    2015-01-01

    This paper reports on the outcomes of a three-year study investigating the use of digital technologies to increase the authenticity of high-stakes summative assessment in four Western Australian senior secondary courses. The study involved 82 teachers and 1015 students and a range of digital forms of assessment using computer-based exams, digital…

  18. Technology Knowledge Self-Assessment and Pre-Test Performance among Digital Natives

    Science.gov (United States)

    Nelms, Keith R.

    2015-01-01

    According to education pundits, traditional-age college students are "digital natives" inherently savvy in digital technology due to their constant exposure to technology from an early age. This widely held meme is at odds with observation in the college classroom. In this research, college students in an introductory information…

  19. The Complexities of Digital Storytelling: Factors Affecting Performance, Production, and Project Completion

    Science.gov (United States)

    Gobel, Peter; Kano, Makimi

    2016-01-01

    Digital storytelling projects provide a variety of opportunities for learning in the language classroom, but along with these opportunities come a number of challenges for both pedagogy and technology. This presentation describes an ongoing multi-method study into factors involved in task-based learning using digital storytelling. Using intact…

  20. Examining the Effectiveness of Digital Video Recordings on Oral Performance of EFL Learners

    Science.gov (United States)

    Göktürk, Nazlinur

    2016-01-01

    This study reports the results of an action-based study conducted in an EFL class to examine whether digital video recordings would contribute to the enhancement of EFL learners' oral fluency skills. It also investigates the learners' perceptions of the use of digital video recordings in a speaking class. 10 Turkish EFL learners participated in…

  1. The Performance Analysis of Traffic Channel Coding in Digital Trunking System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The encoding and decoding processes of traffic channel in digital trunking system are studied. On the basis of computer simulation, the BER (bit error ratio) with different RCPC decoding step is analyzed. As a result, the optimal RCPC decoding step is provided, which gives essential theoretical evidences for the implementation of digital trunking system.

  2. Simultaneous Transmit and Receive Performance of an 8-Channel Digital Phased Array

    Science.gov (United States)

    2017-01-16

    Receive (STAR) could provide significant benefits for many applications including communications, radar, spectral sens- ing, and multifunctional...shown in Fig . 1. Transmit digital beamforming is used to reduce the total coupled power at each receive element, allowing the receive array to maintain...Canceller Receive Digital Beamfomer Isolated Receive SignalTransmit Signal ALSTAR Transmit Elements ALSTAR Receive Elements ... ... Fig . 1

  3. High speed high stakes scoring rule: assessing the performance of a new scoring rule for digital asssesment

    NARCIS (Netherlands)

    Klinkenberg, S.

    2014-01-01

    In this paper we will present the results of a three year subsidized research project investigating the performance of a new scoring rule for digital assessment. The scoring rule incorporates response time and accuracy in an adaptive environment. The project aimed to assess the validity and reliabil

  4. Evaluation of the technical performance of three different commercial digital breast tomosynthesis systems in the clinical environment

    NARCIS (Netherlands)

    Rodriguez Ruiz, A.; Castillo, M.; Garayoa, J.; Chevalier, M.

    2016-01-01

    The aim of this work was to research and evaluate the performance of three different digital breast tomosynthesis (DBT) systems in the clinical environment (Siemens Mammomat Inspiration, Hologic Selenia Dimensions, and Fujifilm Amulet Innovality). The characterization included the study of the

  5. Effect of yoga relaxation techniques on performance of digit-letter substitution task by teenagers

    Directory of Open Access Journals (Sweden)

    Pradhan Balaram

    2009-01-01

    Full Text Available Background/Aims : Memory and selective attention are important skills for academic and professional performance. Techniques to improve these skills are not taught either in education or company training courses. Any system which can systematically improve these skills will be of value in schools, universities, and workplaces. Aims:To investigate possible improvements in memory and selective attention, as measured by the Digit-Letter Substitution Task (DLST, due to practice of Cyclic Meditation (CM, a yoga relaxation technique, as compared to Supine Rest (SR. Materials and Methods : Subjects consisted of 253 school students, 156 boys, 97 girls, in the age range 13-16 years, who were attending a 10-day yoga training course during summer vacation. The selected subjects had English as their medium of instruction in school and they acted as their own controls. They were allocated to two groups, and tested on the DLST, immediately before and after 22.5 minutes practice of CM on one day, and immediately before and after an equal period of SR on the other day. The first group performed CM on day 9 and SR on day 10. For the second group, the order was reversed. Results : Within each group pre-post test differences were significant for both the relaxation techniques. The magnitude of net score improvement was greater after SR (7.85% compared to CM (3.95%. Significance levels were P < 0.4 x 10 -9 for SR and P < 0.1 x 10 -3 for CM. The number of wrong attempts also increased significantly on both interventions, even after removing two outlier data points on day 1 in the SR group. Conclusions: Both CM and SR lead to improvement in performance on the DLST. However, these relaxation techniques lead to more wrong cancellation errors.

  6. Driving without wings: The effect of different digital mirror locations on the visual behaviour, performance and opinions of drivers.

    Science.gov (United States)

    Large, David R; Crundall, Elizabeth; Burnett, Gary; Harvey, Catherine; Konstantopoulos, Panos

    2016-07-01

    Drivers' awareness of the rearward road scene is critical when contemplating or executing lane-change manoeuvres, such as overtaking. Preliminary investigations have speculated on the use of rear-facing cameras to relay images to displays mounted inside the car to create 'digital mirrors'. These may overcome many of the limitations associated with traditional 'wing' and rear-view mirrors, yet will inevitably effect drivers' normal visual scanning behaviour, and may force them to consider the rearward road scene from an unfamiliar perspective that is incongruent with their mental model of the outside world. We describe a study conducted within a medium-fidelity simulator aiming to explore the visual behaviour, driving performance and opinions of drivers while using internally located digital mirrors during different overtaking manoeuvres. Using a generic UK motorway scenario, thirty-eight experienced drivers conducted overtaking manoeuvres using each of five different layouts of digital mirrors with varying degrees of 'real-world' mapping. The results showed reductions in decision time for lane changes and eyes-off road time while using the digital mirrors, when compared with baseline traditional reflective mirrors, suggesting that digital displays may enable drivers to more rapidly pick up the salient information from the rearward road scene. Subjectively, drivers preferred configurations that most closely matched existing mirror locations, where aspects of real-world mapping were largely preserved. The research highlights important human factors issues that require further investigation prior to further development/implementation of digital mirrors within vehicles. Future work should also aim to validate findings within real-world on-road environments whilst considering the effects of digital mirrors on other important visual behaviour characteristics, such as depth perception.

  7. The effects of heavy ion radiation on digital micromirror device performance

    Science.gov (United States)

    Travinsky, Anton; Vorobiev, Dmitry; Raisanen, Alan D.; Pellish, Jonathan; Ninkov, Zoran; Robberto, Massimo; Heap, Sara

    2016-02-01

    There is a need for a space-suitable solution to the selection of targets to be observed in astronomical multiobject spectrometers (MOS). A few digital micromirror device (DMD) - based prototype MOS have been developed for use at ground observatories, However their main use will come in deploying a space based mission. The question of DMD performance under in-orbit radiation remains unanswered. DMDs were tested under accelerated heavy-ion radiation (with the control electronics shielded from radiation), with a focus on detection of single-event effects (SEEs) including latch-up events. Testing showed that DMDs are sensitive to non-destructive ion-induced state changes; however, all SEEs were cleared with a soft reset (that is, sending a new pattern to the device). The DMDs did not experience single-event induced permanent damage or functional changes that required a hard reset (power cycle), even at high ion fluences. This suggests that the SSE rate burden will be manageable for a DMD-based instrument when exposed to solar particle fluxes and cosmic rays on orbit.

  8. Performance Analysis of Video Transmission Using Sequential Distortion Minimization Method for Digital Video Broadcasting Terrestrial

    Directory of Open Access Journals (Sweden)

    Novita Astin

    2016-12-01

    Full Text Available This paper presents about the transmission of Digital Video Broadcasting system with streaming video resolution 640x480 on different IQ rate and modulation. In the video transmission, distortion often occurs, so the received video has bad quality. Key frames selection algorithm is flexibel on a change of video, but on these methods, the temporal information of a video sequence is omitted. To minimize distortion between the original video and received video, we aimed at adding methodology using sequential distortion minimization algorithm. Its aim was to create a new video, better than original video without significant loss of content between the original video and received video, fixed sequentially. The reliability of video transmission was observed based on a constellation diagram, with the best result on IQ rate 2 Mhz and modulation 8 QAM. The best video transmission was also investigated using SEDIM (Sequential Distortion Minimization Method and without SEDIM. The experimental result showed that the PSNR (Peak Signal to Noise Ratio average of video transmission using SEDIM was an increase from 19,855 dB to 48,386 dB and SSIM (Structural Similarity average increase 10,49%. The experimental results and comparison of proposed method obtained a good performance. USRP board was used as RF front-end on 2,2 GHz.

  9. Performance comparison of digital microRNA profiling technologies applied on human breast cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Erik Knutsen

    Full Text Available MicroRNA profiling represents an important first-step in deducting individual RNA-based regulatory function in a cell, tissue, or at a specific developmental stage. Currently there are several different platforms to choose from in order to make the initial miRNA profiles. In this study we investigate recently developed digital microRNA high-throughput technologies. Four different platforms were compared including next generation SOLiD ligation sequencing and Illumina HiSeq sequencing, hybridization-based NanoString nCounter, and miRCURY locked nucleic acid RT-qPCR. For all four technologies, full microRNA profiles were generated from human cell lines that represent noninvasive and invasive tumorigenic breast cancer. This study reports the correlation between platforms, as well as a more extensive analysis of the accuracy and sensitivity of data generated when using different platforms and important consideration when verifying results by the use of additional technologies. We found all the platforms to be highly capable for microRNA analysis. Furthermore, the two NGS platforms and RT-qPCR all have equally high sensitivity, and the fold change accuracy is independent of individual miRNA concentration for NGS and RT-qPCR. Based on these findings we propose new guidelines and considerations when performing microRNA profiling.

  10. Performance improvement of all digital phase-locked loop with adaptive multilevel-quantized phase comparator

    Science.gov (United States)

    Nakajima, Osamu; Hikawa, Hiroomi; Mori, Shinsaku

    1989-03-01

    A new type of phase comparator for DPLL (Digital Phase-Locked Loop), named Adaptive Multilevel-Quantized Phase Comparator (abbreviated as AMPC), is proposed. The characteristics of this proposed comparator AMPC are changed adaptively to reduce the frequency deviation and the phase jitter of the input signals, whereas the conventional phase comparator has constant characteristics whatever signals come. When the offset between input and output signal frequency exists, the amount of frequency control is increased by shifting up or down its chracteristics in order to decrease this deviation. When the loop is in the steady-state, the amount of phase control is decreased by varying the scale of them to suppress the input jitter. Performance characteristics of AMPC and the loop which uses AMPC are analyzed theoretically and verified by computer simulation. As a result, the loop which uses AMPC has much wider locking-range and much better jitter suppression effect than those of the conventional loops, and steady-state phase error is also reduced by using AMPC.

  11. A comparison of the performance of modern screen-film and digital mammography systems

    Energy Technology Data Exchange (ETDEWEB)

    Monnin, P [Institut Universitaire de Radiophysique Appliquee (IRA), CH-1007 Lausanne (Switzerland); Gutierrez, D [Institut Universitaire de Radiophysique Appliquee (IRA), CH-1007 Lausanne (Switzerland); Bulling, S [Institut Universitaire de Radiophysique Appliquee (IRA), CH-1007 Lausanne (Switzerland); Lepori, D [Department of Radiology, University Hospital Center (CHUV), CH-1011 Lausanne (Switzerland); Valley, J-F [Institut Universitaire de Radiophysique Appliquee (IRA), CH-1007 Lausanne (Switzerland); Verdun, F R [Institut Universitaire de Radiophysique Appliquee (IRA), CH-1007 Lausanne (Switzerland)

    2005-06-07

    This work compares the detector performance and image quality of the new Kodak Min-R EV mammography screen-film system with the Fuji CR Profect detector and with other current mammography screen-film systems from Agfa, Fuji and Kodak. Basic image quality parameters (MTF, NPS, NEQ and DQE) were evaluated for a 28 kV Mo/Mo (HVL = 0.646 mm Al) beam using different mAs exposure settings. Compared with other screen-film systems, the new Kodak Min-R EV detector has the highest contrast and a low intrinsic noise level, giving better NEQ and DQE results, especially at high optical density. Thus, the properties of the new mammography film approach those of a fine mammography detector, especially at low frequency range. Screen-film systems provide the best resolution. The presampling MTF of the digital detector has a value of 15% at the Nyquist frequency and, due to the spread size of the laser beam, the use of a smaller pixel size would not permit a significant improvement of the detector resolution. The dual collection reading technology increases significantly the low frequency DQE of the Fuji CR system that can at present compete with the most efficient mammography screen-film systems.

  12. Performance comparison of digital microRNA profiling technologies applied on human breast cancer cell lines.

    Science.gov (United States)

    Knutsen, Erik; Fiskaa, Tonje; Ursvik, Anita; Jørgensen, Tor Erik; Perander, Maria; Lund, Eiliv; Seternes, Ole Morten; Johansen, Steinar D; Andreassen, Morten

    2013-01-01

    MicroRNA profiling represents an important first-step in deducting individual RNA-based regulatory function in a cell, tissue, or at a specific developmental stage. Currently there are several different platforms to choose from in order to make the initial miRNA profiles. In this study we investigate recently developed digital microRNA high-throughput technologies. Four different platforms were compared including next generation SOLiD ligation sequencing and Illumina HiSeq sequencing, hybridization-based NanoString nCounter, and miRCURY locked nucleic acid RT-qPCR. For all four technologies, full microRNA profiles were generated from human cell lines that represent noninvasive and invasive tumorigenic breast cancer. This study reports the correlation between platforms, as well as a more extensive analysis of the accuracy and sensitivity of data generated when using different platforms and important consideration when verifying results by the use of additional technologies. We found all the platforms to be highly capable for microRNA analysis. Furthermore, the two NGS platforms and RT-qPCR all have equally high sensitivity, and the fold change accuracy is independent of individual miRNA concentration for NGS and RT-qPCR. Based on these findings we propose new guidelines and considerations when performing microRNA profiling.

  13. Performance requirements for analog-to-digital converters in wideband reconfigurable radios

    Science.gov (United States)

    Naughton, David; Baldwin, Gerard; Farrell, Ronan

    2005-06-01

    With the current trend towards software defined radio, several candidate architectures for the analog receiver front-end have been presented. A common proposal for software defined reconfigurable radio is to develop a wideband ADC and utilise this for capturing a large segment of the spectrum. This would enable the subsequent signal processing operations of channel selection and data extraction to be carried out by a digital processor. This would allow the radio to be reconfigured by simply changing the software. In analysis of these systems, powerful neighbouring signals, or blockers, are considered but it has been conveniently assumed that suitable dynamic range will be available at the ADC. This is an acceptable assumption in narrowband systems where automatic gain control and analogue channel select filters can be used, but is not appropriate for a wideband system. In this paper we present an analysis based on bit-error-rates (BER) which shows the effect of blockers in a wideband architecture on the performance of the communication link and on the dynamic range requirements of the ADC.

  14. Performing continuous quality improvement for a digital health sciences library through an electronic mail analysis.

    Science.gov (United States)

    D'Alessandro, D M; Qian, F; D'Alessandro, M P; Ostrem, S F; Choi, T A; Erkonen, W E; Galvin, J R

    1998-01-01

    BACKGROUND: The goal of this prospective, cross-sectional study was to determine the user demographics of a digital health sciences library (DHSL), motives for use, the nature of users information requests, and success rate in finding answers. METHODS: The content of 500 consecutive electronic mail messages (e-mails) submitted to a DHSL were analyzed using a predetermined coding scheme. Data were entered into a database and frequency analysis was performed. RESULTS: The number of information requests from the 500 e-mail messages was 751. The largest sender category was patients and laypersons followed by students, then physicians. Motivations for use were primarily medical advice (42.8%) and patient care (13.8%). E-mail subject areas were mainly medical (61.8%) and technical (20.6%). Answers to information requests were found 54.3% of the time and senders felt the DHSL was valuable (97.8%). CONCLUSIONS: A DHSL is a valuable medical resource. DHSLs must serve the broad information needs of patients and laypersons in addition to health care providers. Developers and managers of DHSLs can use this information to guide future development of DHSL information content and services, as has been done at The University of Iowa. PMID:9803305

  15. Enhancing the usage pattern mining performance with temporal segmentation of QPop Increment in digital libraries

    Institute of Scientific and Technical Information of China (English)

    CAO San-xing; KLEIN R.Rody; LIU Jian-bo

    2005-01-01

    The convergence of next-generation Networks and the emergence of new media systems have made media-rich digital libraries popular in application and research. The discovery of media content objects' usage patterns, where QPop Increment is the characteristic feature under study, is the basis of intelligent data migration scheduling, the very key issue for these systems to manage effectively the massive storage facilities in their backbones. In this paper, a clustering algorithm is established, on the basis of temporal segmentation of QPop Increment, so as to improve the mining performance. We employed the standard C-Means algorithm as the clustering kernel, and carried out the experimental mining process with segmented QPop Increases obtained in actual applications. The results indicated that the improved algorithm is more advantageous than the basic one in important indices such as the clustering cohesion. The experimental study in this paper is based on a Media Assets Library prototype developed for the use of the advertainment movie production project for Olympics 2008, under the support of both the Humanistic Olympics Study Center in Beijing, and China State Administration of Radio, Film and TV.

  16. Simulation and Measurement of the Transmission Distortions of the Digital Television DVB-T/H Part 2: Hierarchical Modulation Performance

    Directory of Open Access Journals (Sweden)

    R. Stukavec

    2010-09-01

    Full Text Available The paper deals with the second part of results of the Czech Science Foundation research project that was aimed into the simulation and measurement of the transmission distortions of the digital terrestrial television according to DVB-T/H standards. In this part the hierarchical modulation performance characteristics and its simulation and laboratory measurements are presented. The paper deals with the hierarchical oriented COFDM modulator for the digital terrestrial television transmission and DVB-T/H standards and possible utilization of this technique in real broadcasting scenarios – fixed, portable and mobile digital TV, all in one TV channel. Impact of the hierarchical modulation on Modulation Error Rate from I/Q constellations and Bit Error Rates before and after Viterbi decoding in DVB-T/H signal decoding are evaluated and discussed.

  17. Performance study of Philips digital silicon photomultiplier coupled to scintillating crystals

    CERN Document Server

    Liu, Z.; Auffray, E.; Lecoq, P.; Paganoni, M.

    2016-01-01

    Silicon photomultipliers (SiPMs) and scintillators are often arranged in the shape of arrays in Positron Emission Tomography (PET) systems. Digital SiPMs provide signal readout in single photon avalanche diode (SPAD) level. From the photon count rate measurement of each SPAD cell of digital SiPM, we found that the output scintillating photons distribute in an area larger than the scintillator physical coupling area. Taking advantage of the possibility to enable/disable individual cells of the digital SiPM, a group of Lutetium-yttrium oxyorthosilicate (LYSO) crystals with different dimensions coupled to a digital SiPM was used to study the influence of using different SiPM active area on the number of photons detected, energy resolution and coincidence time resolution (CTR). For the same crystal coupled to the digital SiPM, the larger the active area of digital SiPM, the higher the number of photons detected. The larger active area of the digital SiPM also results in a better energy resolution after saturation...

  18. Image performance of a new amorphous selenium flat panel x-ray detector designed for digital breast tomosynthesis

    Science.gov (United States)

    Cheung, L. K.; Jing, Z.; Bogdanovich, S.; Golden, K.; Robinson, S.; Beliaevskaia, E.; Parikh, S.

    2005-04-01

    The purpose of this work is to report the performance of an amorphous selenium (a-Se) based flat-panel x-ray imager under development for application in digital breast tomosynthesis. This detector is designed to perform both in the conventional Full Field Digital Mammography (FFDM) mode and the tomosynthesis mode. The large area 24 x 29 cm detector achieves rapid image acquisition rates of up to 4 frames per second with minimal trapped charge induced effects such as ghost or lag images of previously acquired objects. In this work, a new a-Se/TFT detector layer structure is evaluated. The design uses a top conductive layer in direct contact with the a-Se x-ray detection layer. The simple structure has few layers and minimal hole and electron trapping effects. Prototype detectors were built to investigate the basic image performance of this new a-Se/TFT detector. Image signal generation, image ghosting, image lag, and detector DQE were studied. For digital mammography applications, the residual image ghosting was less than 1% at 30 seconds elapsed time. DQE, measured at a field of 5.15 V/um, showed significantly higher values over previously reported data, especially at low exposure levels. For digital breast tomosynthesis, the image lag at dynamic readout rate was < 0.6 % at 0.5-second elapsed time. A prototype tomosynthesis system is being developed utilizing this new a-Se/TFT detector.

  19. Performance of the Fully Digital FPGA-based Front-End Electronics for the GALILEO Array

    CERN Document Server

    Barrientos, D; Bazzacco, D; Bortolato, D; Cocconi, P; Gadea, A; González, V; Gulmini, M; Isocrate, R; Mengoni, D; Pullia, A; Recchia, F; Rosso, D; Sanchis, E; Toniolo, N; Ur, C A; Valiente-Dobón, J J

    2014-01-01

    In this work we present the architecture and results of a fully digital Front End Electronics (FEE) read out system developed for the GALILEO array. The FEE system, developed in collaboration with the Advanced Gamma Tracking Array (AGATA) collaboration, is composed of three main blocks: preamplifiers, digitizers and preprocessing electronics. The slow control system contains a custom Linux driver, a dynamic library and a server implementing network services. The digital processing of the data from the GALILEO germanium detectors has demonstrated the capability to achieve an energy resolution of 1.53 per mil at an energy of 1.33 MeV.

  20. Comparing the performance of various digital soil mapping approaches to map physical soil properties

    Science.gov (United States)

    Laborczi, Annamária; Takács, Katalin; Pásztor, László

    2015-04-01

    digital soil mapping methods and sets of ancillary variables for producing the most accurate spatial prediction of texture classes in a given area of interest. Both legacy and recently collected data on PSD were used as reference information. The predictor variable data set consisted of digital elevation model and its derivatives, lithology, land use maps as well as various bands and indices of satellite images. Two conceptionally different approaches can be applied in the mapping process. Textural classification can be realized after particle size data were spatially extended by proper geostatistical method. Alternatively, the textural classification is carried out first, followed by the spatial extension through suitable data mining method. According to the first approach, maps of sand, silt and clay percentage have been computed through regression kriging (RK). Since the three maps are compositional (their sum must be 100%), we applied Additive Log-Ratio (alr) transformation, instead of kriging them independently. Finally, the texture class map has been compiled according to the USDA categories from the three maps. Different combinations of reference and training soil data and auxiliary covariables resulted several different maps. On the basis of the other way, the PSD were classified firstly into the USDA categories, then the texture class maps were compiled directly by data mining methods (classification trees and random forests). The various results were compared to each other as well as to the RK maps. The performance of the different methods and data sets has been examined by testing the accuracy of the geostatistically computed and the directly classified results to assess the most predictive and accurate method. Acknowledgement: Our work was supported by the Hungarian National Scientific Research Foundation (OTKA, Grant No. K105167).

  1. Technical and clinical breast cancer screening performance indicators for computed radiography versus direct digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Bosmans, Hilde; Lemmens, Kim; Zanca, Federica; Ongeval, Chantal van; Steen, Andre van [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Hauwere, An de; Thierens, Hubert [Ghent University, QCC, Ghent (Belgium); Herck, Koen van; Bleyen, Luc; Mortier, Griet [Ghent University, Centrum voor Preventie en Vroegtijdige Opsporing van Kanker, Department of Public Health, Ghent (Belgium); Martens, Patrick [Vroegtijdige Opsporing Borstklierkanker West-Vlaanderen vzw, Bruges (Belgium); Putte, Gretel vande; Kellen, Eliane; Limbergen, Erik van [Leuven University Center of Cancer Screening, Leuven (Belgium)

    2013-10-15

    To compare technical and clinical screening performance parameters between computed radiography (CR) and direct digital radiography (DR) systems. The number of women screened with CR was 73,008 and with DR 116,945. Technical and patient dose survey data of 25 CR and 37 DR systems were available. Technical performance was expressed by threshold thickness values at the mean glandular dose (MGD) level of routine practice. Clinical indicators included recall rate (RR), cancer detection rate (CDR), percentage of ductal carcinoma in situ (DCIS), percentage of cancers with T-scores smaller than 1 cm and positive predictive value (PPV). Contrast threshold values for the 0.1-mm gold disk were 1.44 {mu}m (SD 0.13 {mu}m) for CR and 1.20 {mu}m (SD 0.13 {mu}m for DR). MGD was 2.16 mGy (SD 0.36 mGy) and 1.35 mGy (SD 0.32 mGy) for CR and DR respectively. We obtained for CR, respectively DR, the following results: RR in the first round of 5.48 % versus 5.61 %; RR in subsequent rounds of 2.52 % versus 2.65 %; CDR of 0.52 % versus 0.53 %; DCIS of 0.08 % versus 0.11 %; a rate of cancers with T-scores smaller than 1 cm of 0.11 % versus 0.11 %; PPV of 18.45 % versus 18.64 %; none of them was significantly different. Our screening indicators are reassuring for the use of CR and DR, with CR operating at 60 % higher MGD. (orig.)

  2. Diagnostic performance of digital breast tomosynthesis with a wide scan angle compared to full-field digital mammography for the detection and characterization of microcalcifications.

    Science.gov (United States)

    Clauser, Paola; Nagl, Georg; Helbich, Thomas H; Pinker-Domenig, Katja; Weber, Michael; Kapetas, Panagiotis; Bernathova, Maria; Baltzer, Pascal A T

    2016-12-01

    To assess the diagnostic performance of digital breast tomosynthesis (DBT), with a wide scan-angle, compared to full-field digital mammography (FFDM), for the detection and characterization of microcalcifications. IRB approval was obtained for this retrospective study. We selected 150 FFDM and DBT (50 benign and 50 malignant histologically verified microcalcifications, 50 cases classified as BI-RADS 1). Four radiologists evaluated, in separate sessions and blinded to patients' history and histology, the presence of microcalcifications. Cases with microcalcifications were assessed for visibility, characteristics, and grade of suspicion using BI-RADS categories. Detection rate and diagnostic performance were calculated. Visibility, lesions' characteristics and reading time were analysed. Detection rate and visibility were good for both FFDM and DBT, without intra-reader differences (P=0.510). Inter-reader differences were detected (PReading time for DBT was almost twice that for FFDM (44 and 25s, respectively). Wide scan-angle DBT enabled the detection and characterization of microcalcifications with no significant differences from FFDM. Inter-reader variability was seen. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Digital Reading in PISA 2012 and ICT Uses: How Do VET and General Education Students Perform? JRC Science for Policy Report

    Science.gov (United States)

    Dinis da Costa, Patrícia; Araújo, Luísa

    2016-01-01

    The analyses presented in this report indicate that in several Member States (MS) 15-year-old students in vocational-oriented programmes (VET) perform better in digital reading than in print reading in PISA 2012. When differentiated by programme of study--VET versus general education programmes--VET students perform better in digital than in print…

  4. Image-quality performance of an a-Si H-based X-ray imaging system for digital mammography

    CERN Document Server

    Darambara, D G; Speller, R D

    2002-01-01

    We have been investigating the potential of large area active matrix flat-panel a-Si : H imaging arrays for full-field digital X-ray mammography. To optimise the overall performance of such an imaging system under mammographic conditions, four different Gd sub 2 O sub 2 S : Tb phosphor screens (i.e. Lanex Fast-Back, Regular, Fine and MinR-2000) were employed and our full-field detector was integrated with the Feinfocus DIMA (Direct Magnification) PLUS MII mammographic unit. The spatial resolution and the image noise of the digital detector were measured and the X-ray imaging performance of the whole system was also evaluated with two mammographic phantoms. It was deduced from the results of this study that Regular screen offers the best compromise between sensitivity and spatial resolution and exhibits better overall image-quality performance than that of a conventional mammography system.

  5. The Effect of Degraded Digital Instrumentation and Control systems on Human-system Interfaces and Operator Performance

    Energy Technology Data Exchange (ETDEWEB)

    OHara, J.M.; Gunther, B.; Martinez-Guridi, G. (BNL); Xing, J.; Barnes, V. (NRC)

    2010-11-07

    Integrated digital instrumentation and control (I&C) systems in new and advanced nuclear power plants (NPPs) will support operators in monitoring and controlling the plants. Even though digital systems typically are expected to be reliable, their potential for degradation or failure significantly could affect the operators performance and, consequently, jeopardize plant safety. This U.S. Nuclear Regulatory Commission (NRC) research investigated the effects of degraded I&C systems on human performance and on plant operations. The objective was to develop technical basis and guidance for human factors engineering (HFE) reviews addressing the operator's ability to detect and manage degraded digital I&C conditions. We reviewed pertinent standards and guidelines, empirical studies, and plant operating experience. In addition, we evaluated the potential effects of selected failure modes of the digital feedwater control system of a currently operating pressurized water reactor (PWR) on human-system interfaces (HSIs) and the operators performance. Our findings indicated that I&C degradations are prevalent in plants employing digital systems, and the overall effects on the plant's behavior can be significant, such as causing a reactor trip or equipment to operate unexpectedly. I&C degradations may affect the HSIs used by operators to monitor and control the plant. For example, deterioration of the sensors can complicate the operators interpretation of displays, and sometimes may mislead them by making it appear that a process disturbance has occurred. We used the findings as the technical basis upon which to develop HFE review guidance.

  6. Comparative performance of modern digital mammography systems in a large breast screening program

    Energy Technology Data Exchange (ETDEWEB)

    Yaffe, Martin J., E-mail: martin.yaffe@sri.utoronto.ca; Bloomquist, Aili K.; Hunter, David M.; Mawdsley, Gordon E. [Physical Sciences Division, Sunnybrook Research Institute, Departments of Medical Biophysics and Medical Imaging, University of Toronto, Ontario M4N 3M5 (Canada); Chiarelli, Anna M. [Prevention and Cancer Control, Cancer Care Ontario, Dalla Lana School of Public Health, University of Toronto, Ontario M4N 3M5, Canada and Ontario Breast Screening Program, Cancer Care Ontario, Toronto, Ontario M5G 1X3 (Canada); Muradali, Derek [Ontario Breast Screening Program, Cancer Care Ontario, Toronto, Ontario M5G 1X3 (Canada); Mainprize, James G. [Physical Sciences Division, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5 (Canada)

    2013-12-15

    Purpose: To compare physical measures pertaining to image quality among digital mammography systems utilized in a large breast screening program. To examine qualitatively differences in these measures and differences in clinical cancer detection rates between CR and DR among sites within that program. Methods: As part of the routine quality assurance program for screening, field measurements are made of several variables considered to correlate with the diagnostic quality of medical images including: modulation transfer function, noise equivalent quanta, d′ (an index of lesion detectability) and air kerma to allow estimation of mean glandular dose. In addition, images of the mammography accreditation phantom are evaluated. Results: It was found that overall there were marked differences between the performance measures of DR and CR mammography systems. In particular, the modulation transfer functions obtained with the DR systems were found to be higher, even for larger detector element sizes. Similarly, the noise equivalent quanta, d′, and the phantom scores were higher, while the failure rates associated with low signal-to-noise ratio and high dose were lower with DR. These results were consistent with previous findings in the authors’ program that the breast cancer detection rates at sites employing CR technology were, on average, 30.6% lower than those that used DR mammography. Conclusions: While the clinical study was not large enough to allow a statistically powered system-by-system assessment of cancer detection accuracy, the physical measures expressing spatial resolution, and signal-to-noise ratio are consistent with the published finding that sites employing CR systems had lower cancer detection rates than those using DR systems for screening mammography.

  7. The effects of heavy ion radiation on digital micromirror device performance

    Science.gov (United States)

    Travinsky, Anton; Vorobiev, Dmitry; Ninkov, Zoran; Raisanen, Alan D.; Pellish, Jonathan A.; Robberto, Massimo; Heap, Sara

    2016-07-01

    There is a pressing need in the astronomical community for space-suitable multi-object spectrometers (MOSs). Several digital micromirror device (DMD)-based prototype MOSs have been developed for ground-based observatories; however, their main use will come with deployment on a space based mission. Therefore, performance of DMDs under exoatmospheric radiation needs to be evaluated. In our previous work we demonstrated that DMDs are tolerant to heavy ion irradiation in general and calculated upset rate of 4.3 micromirrors in 24 hours in orbit for 1-megapixel device. The goal of this additional experiment was to acquire more data and therefore increase the accuracy of the predicted in-orbit micromirror upset rate. Similar to the previous experiment, for this testing 0.7 XGA DMDs were re-windowed with 2 μm thick pellicle and tested under accelerated heavy-ion radiation (with control electronics shielded from radiation) with a focus on detection of single-event upsets (SEUs). We concentrated on ions with low levels of linear energy transfer (LET) 1.8 - 13 MeV•cm2•mg-1 to cover the most critical range of the Weibull curve for those devices. As during the previous experiment, we observed and documented non-destructive heavy ion-induced micromirror state changes. All SEUs were always cleared with a soft reset (that is, sending a new pattern to the device). The DMDs we tested did not experience single-event induced permanent damage or functional changes that required a hard reset (power cycle), even at high ion fluences. Based on the data obtained in the experiments we predict micromirror in-orbit upset rate of 5.6 micromirrors in 24 hours in-orbit for the tested devices. This suggests that the heavy-ion induced SEU rate burden for a DMD-based instrument will be manageable when exposed to solar particle fluxes and cosmic rays in orbit.

  8. On the Performance of Classification Techniques with Pixel Removal Applied to Digit Recognition

    Directory of Open Access Journals (Sweden)

    Jozette V. Roberts

    2016-08-01

    Full Text Available The successive loss of the outermost pixel values or frames in the digital representation of handwritten digits is postulated to have an increasing impact on the degree of accuracy of categorizations of these digits. This removal of frames is referred to as trimming. The first few frames do not contain significant amounts of information and the impact on accuracy should be negligible. As more frames are trimmed, the impact becomes more significant on the ability of each classification model to correctly identify digits. This study focuses on the effects of the trimming of frames of pixels, on the ability of the Recursive Partitioning and Classification Trees method, the Naive Bayes method, the k-Nearest Neighbor method and the Support Vector Machine method in the categorization of handwritten digits. The results from the application of the k-Nearest Neighbour and Recursive Partitioning and Classification Trees methods exemplified the white noise effect in the trimming of the first few frames whilst the Naive Bayes and the Support Vector Machine did not. With respect to time all models saw a relative decrease in time from the initial dataset. The k-Nearest Neighbour method had the greatest decreases whilst the Support Vector Machine had significantly fluctuating times.

  9. Performance differences between adult heterosexual and homosexual men on the Digit-Symbol Substitution subtest of the WAIS-R.

    Science.gov (United States)

    Rahman, Qazi; Wilson, Glenn D; Abrahams, Sharon

    2004-02-01

    Previous evidence suggests that sexual orientation influences performance on a number of cognitive functions known to be sexually dimorphic. This investigation examined the performance of 240 right-handed subjects (60 heterosexual men, 60 homosexual men, 60 heterosexual women and 60 homosexual women) on one of the most commonly used neuropsychological tests to show normative sex differences, the Digit-Symbol Substitution test of the WAIS-R. Analysis of scaled Digit-Symbol scores revealed that heterosexual women and homosexual men outperformed heterosexual men. The magnitude of these differences were modest by standard criteria. No differences were found between heterosexual and homosexual women. The findings implicate within-sex variation in one test that relies on intact executive function.

  10. A high performance cost-effective digital complex correlator for an X-band polarimetry survey.

    Science.gov (United States)

    Bergano, Miguel; Rocha, Armando; Cupido, Luís; Barbosa, Domingos; Villela, Thyrso; Boas, José Vilas; Rocha, Graça; Smoot, George F

    2016-01-01

    The detailed knowledge of the Milky Way radio emission is important to characterize galactic foregrounds masking extragalactic and cosmological signals. The update of the global sky models describing radio emissions over a very large spectral band requires high sensitivity experiments capable of observing large sky areas with long integration times. Here, we present the design of a new 10 GHz (X-band) polarimeter digital back-end to map the polarization components of the galactic synchrotron radiation field of the Northern Hemisphere sky. The design follows the digital processing trends in radio astronomy and implements a large bandwidth (1 GHz) digital complex cross-correlator to extract the Stokes parameters of the incoming synchrotron radiation field. The hardware constraints cover the implemented VLSI hardware description language code and the preliminary results. The implementation is based on the simultaneous digitized acquisition of the Cartesian components of the two linear receiver polarization channels. The design strategy involves a double data rate acquisition of the ADC interleaved parallel bus, and field programmable gate array device programming at the register transfer mode. The digital core of the back-end is capable of processing 32 Gbps and is built around an Altera field programmable gate array clocked at 250 MHz, 1 GSps analog to digital converters and a clock generator. The control of the field programmable gate array internal signal delays and a convenient use of its phase locked loops provide the timing requirements to achieve the target bandwidths and sensitivity. This solution is convenient for radio astronomy experiments requiring large bandwidth, high functionality, high volume availability and low cost. Of particular interest, this correlator was developed for the Galactic Emission Mapping project and is suitable for large sky area polarization continuum surveys. The solutions may also be adapted to be used at signal processing

  11. Persian randomized dichotic digits test: Development and dichotic listening performance in young adults

    Directory of Open Access Journals (Sweden)

    Mohammad Ebrahim Mahdavi

    2015-02-01

    Full Text Available Background and Aims: The dichotic listening subtest is an important component of the test battery for auditory processing assessment in both children and adults. A randomized dichotic digits test (RDDT was created to compensate for sensitivity weakness of double digits when detecting abnormal ear asymmetry during dichotic listening. The aim of this study was the development and  intial evaluation of the Persian randomized dichotic digits test.Method: Persian digits 1-10 (except for the bisyllabic digit, 4 uttered by a native Persian language speaker were recorded in a studio. After alignment of intensity and temporal characteristics of digit waveforms, lists 1 and 2 of the RDDT were reproduced. List 1 of the test was administered at 55 dBHL on 50 right-handed normal hearing individuals (with an equal sex ratio in the age group of 18-25 years and hearing thresholds of 15 dBHL or better in audiometric frequencies.Results: Mean (standard deviation of percent-correct score for right and left ears and right ear advantage of the subjects was 94.3 (5.3, 84.8 (7.7, and 9.5 (7.0 percent, respectively. Sixty percent of the subjects showed normal results and unilateral and bilateral deficits were seen in 24 percent and 16 percent, respectively, of studied individuals.Conclusion: It seems the Persian version of RDDT test is the same as the original test as it is able to test ear asymmerty, unilateral and bilateral deficits in dichotic listening.

  12. PERFORMANCE EVALUATION OF LOW DENSITY PARITY CHECK CODES FOR DIGITAL RADIO MONDIALE (DRM) SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In Digital Radio Mondiale (DRM) system, achieving good audio quality becomes a challenge due to its limited band-width of 9 or 10kHz and the very bad fading channels. Therefore, DRM needs highly efficient channel coding schemes. This paper, proposes the schemes which use the Low-Density Parity-Check (LDPC) coded Bit-Interleaved Coded Modulation (BICM) schemes for the implementation of DRM systems.Simulation results show that the proposed system is more efficient than the Rate Compatible Punctured Convolutional (RCPC) coded DRM system on various broadcast channels, and may be recommended as a coding technology for Digital Amplitude Modulation Broadcasting (DAMB) systems of China.

  13. Comparison of the diagnostic performance of digital breast tomosynthesis and magnetic resonance imaging added to digital mammography in women with known breast cancers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won Hwa; Chang, Jung Min; Moon, Woo Kyung [Seoul National University Hospital, Department of Radiology, 101 Daehangno, Jongno-gu, Seoul (Korea, Republic of); Moon, Hyeong-Gon [Seoul National University Hospital, Department of Surgery, Seoul (Korea, Republic of); Yi, Ann [Seoul National University Hospital, Department of Radiology, Gangnan Healthcare Center, Seoul (Korea, Republic of); Koo, Hye Ryoung [Hanyang University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Gweon, Hye Mi [Yonsei University College of Medicine, Department of Radiology, Gangnam Severance Hospital, Seoul (Korea, Republic of)

    2016-06-15

    To compare the diagnostic performance of digital breast tomosynthesis (DBT) and magnetic resonance imaging (MRI) added to mammography in women with known breast cancers. Three radiologists independently reviewed image sets of 172 patients with 184 cancers; mammography alone, DBT plus mammography and MRI plus mammography, and scored for cancer probability using the Breast Imaging Reporting and Data System (BI-RADS). Jack-knife alternative free-response receiver-operating characteristic (JAFROC), which allows diagnostic performance estimation using single lesion as a statistical unit in a cancer-only population, was used. Sensitivity and positive predictive value (PPV) were compared using the McNemar and Fisher-exact tests. The JAFROC figures of merit (FOMs) was lower in DBT plus mammography (0.937) than MRI plus mammography (0.978, P = 0.0006) but higher than mammography alone (0.900, P = 0.0013). The sensitivity was lower in DBT plus mammography (88.2 %) than MRI plus mammography (97.8 %) but higher than mammography alone (78.3 %, both P < 0.0001). The PPV was significantly higher in DBT plus mammography (93.3 %) than MRI plus mammography (89.6 %, P = 0.0282). DBT provided lower diagnostic performance than MRI as an adjunctive imaging to mammography. However, DBT had higher diagnostic performance than mammography and higher PPV than MRI. (orig.)

  14. High Performance Digital Media Network (HPDMnet): An advanced international research initiative and global experimental testbed

    NARCIS (Netherlands)

    Mambretti, J.; Lemay, M.; Campbell, S.; Guy, H.; Tam, T.; Bernier, E.; Ho, B.; Savoie, M.; de Laat, C.; van der Pol, R.; Chen, J.; Yeh, F.; Figuerola, S.; Minoves, P.; Simeonidou, D.; Escalona, E.; Gonzalez, N.A.; Jukan, A.; Bziuk, W.; Kim, D.; Cho, K.; Lee, H.L.; Liu, T.L.

    2011-01-01

    Currently, support for digital media is one of the fastest growing requirements of the Internet as demand transitions from services designed to support primarily text and images to those intended also to support rich, high quality streaming multi-media. In response to the need to address this import

  15. Performance evaluation of image enhancement techniques on a digital image-intensifier

    NARCIS (Netherlands)

    Dijk, J.; Bijl, P.; Bouma, H.

    2009-01-01

    Recently new techniques for night-vision cameras are developed. Digital image-intensifiers are becoming available on the market. Also, so-called EMCCD cameras are developed, which may even be able to record color information about the scene. However, in low-light situations all night-vision imagery

  16. Recurso didático digital: complexidade da performance docente na produção (hipertextual

    Directory of Open Access Journals (Sweden)

    Juliana Sales Jacques

    2015-12-01

    O recurso didático digital, no âmbito do ensino-aprendizagem mediado por tecnologias em rede, constitui-se como mediador não humano que estabelece a relação entre o professor, o estudante e o saber a ser ensinado. A complexidade da performance docente no processo de transposição didática é elemento catalisador da complexidade da produção (hipertextual mediada por tecnologias em rede. Neste artigo, a partir de revisão de literatura, argumentamos sobre a produção de recurso didático digital à luz da concepção interacionista da linguagem. Nesse viés, dado que a linguagem é dotada de intencionalidade, o propósito de um recurso didático digital é, como ação inerente ao processo ensino-aprendizagem, transformar através da palavra escrita (linguagem verbal atrelada a todas as formas (sonora, visual, audiovisual, etc. que perpassam o universo da linguagem. Inferimos, como considerações finais, que a transformação pressupõe, na produção do texto digital (recurso didático, inovação no design pedagógico. E, diante disso, defendemos como inovação, além da integração hipermidiática, a produção aberta em rede através da autoria e coautoria. Tudo isso para que, dentro de uma vertente linguística interacionista, as diferentes formas de leitura potencializem além da produção, a negociação de sentidos do (hipertexto como recurso didático digital.

  17. Performances on Symbol Digit Modalities Test, Color Trails Test, and modified Stroop test in a healthy, elderly Danish sample

    DEFF Research Database (Denmark)

    Vogel, Asmus; Stokholm, Jette; Jørgensen, Kasper

    2013-01-01

    for different age groups. For SDMT and CTT1, Danish Adult Reading Test (DART) score also had a significant impact on test performances. The incongruent version of the modified Stroop test was significantly correlated to education. Moderate and significant correlations were found between the three tests. Even......This study presents Danish data for the Symbol Digit Modalities Test (SDMT), Color Trails Test (CTT), and a modified Stroop test from 100 subjects aged 60-87 years. Among the included demographic variables, age had the highest impact on test performances. Thus, the study presents separate data...

  18. SEMICONDUCTOR INTEGRATED CIRCUITS: A high-performance, low-power σ Δ ADC for digital audio applications

    Science.gov (United States)

    Hao, Luo; Yan, Han; Cheung, Ray C. C.; Xiaoxia, Han; Shaoyu, Ma; Peng, Ying; Dazhong, Zhu

    2010-05-01

    A high-performance low-power σ Δ analog-to-digital converter (ADC) for digital audio applications is described. It consists of a 2-1 cascaded σ Δ modulator and a decimation filter. Various design optimizations are implemented in the system design, circuit implementation and layout design, including a high-overload-level coefficient-optimized modulator architecture, a power-efficient class A/AB operational transconductance amplifier, as well as a multi-stage decimation filter conserving area and power consumption. The ADC is implemented in the SMIC 0.18-μm CMOS mixed-signal process. The experimental chip achieves a peak signal-to-noise-plus-distortion ratio of 90 dB and a dynamic range of 94 dB over 22.05-kHz audio band and occupies 2.1 mm2, which dissipates only 2.1 mA quiescent current in the analog circuits.

  19. The TOMMY trial: a comparison of TOMosynthesis with digital MammographY in the UK NHS Breast Screening Programme--a multicentre retrospective reading study comparing the diagnostic performance of digital breast tomosynthesis and digital mammography with digital mammography alone.

    Science.gov (United States)

    Gilbert, Fiona J; Tucker, Lorraine; Gillan, Maureen Gc; Willsher, Paula; Cooke, Julie; Duncan, Karen A; Michell, Michael J; Dobson, Hilary M; Lim, Yit Yoong; Purushothaman, Hema; Strudley, Celia; Astley, Susan M; Morrish, Oliver; Young, Kenneth C; Duffy, Stephen W

    2015-01-01

    Digital breast tomosynthesis (DBT) is a three-dimensional mammography technique with the potential to improve accuracy by improving differentiation between malignant and non-malignant lesions. The objectives of the study were to compare the diagnostic accuracy of DBT in conjunction with two-dimensional (2D) mammography or synthetic 2D mammography, against standard 2D mammography and to determine if DBT improves the accuracy of detection of different types of lesions. Women (aged 47-73 years) recalled for further assessment after routine breast screening and women (aged 40-49 years) with moderate/high of risk of developing breast cancer attending annual mammography screening were recruited after giving written informed consent. All participants underwent a two-view 2D mammography of both breasts and two-view DBT imaging. Image-processing software generated a synthetic 2D mammogram from the DBT data sets. In an independent blinded retrospective study, readers reviewed (1) 2D or (2) 2D + DBT or (3) synthetic 2D + DBT images for each case without access to original screening mammograms or prior examinations. Sensitivities and specificities were calculated for each reading arm and by subgroup analyses. Data were available for 7060 subjects comprising 6020 (1158 cancers) assessment cases and 1040 (two cancers) family history screening cases. Overall sensitivity was 87% [95% confidence interval (CI) 85% to 89%] for 2D only, 89% (95% CI 87% to 91%) for 2D + DBT and 88% (95% CI 86% to 90%) for synthetic 2D + DBT. The difference in sensitivity between 2D and 2D + DBT was of borderline significance (p = 0.07) and for synthetic 2D + DBT there was no significant difference (p = 0.6). Specificity was 58% (95% CI 56% to 60%) for 2D, 69% (95% CI 67% to 71%) for 2D + DBT and 71% (95% CI 69% to 73%) for synthetic 2D + DBT. Specificity was significantly higher in both DBT reading arms for all subgroups of age, density and dominant radiological

  20. Digital design and experimental validation of high-performance real-time OFDM systems

    OpenAIRE

    Font Bach, Josep Oriol

    2013-01-01

    The goal of this Ph.D. dissertation is to address a number of challenges encountered in the digital baseband design of modern and future wireless communication systems. The fast and continuous evolution of wireless communications has been driven by the ambitious goal of providing ubiquitous services that could guarantee high throughput, reliability of the communication link and satisfy the increasing demand for efficient re-utilization of the heavily populated wireless spectrum. To cope with ...

  1. Microvalve Enabled Digital Microfluidic Systems for High Performance Biochemical and Genetic Analysis.

    Science.gov (United States)

    Jensen, Erik C; Zeng, Yong; Kim, Jungkyu; Mathies, Richard A

    2010-12-01

    Microfluidic devices offer unparalleled capability for digital microfluidic automation of sample processing and complex assay protocols in medical diagnostic and research applications. In our own work, monolithic membrane valves have enabled the creation of two platforms that precisely manipulate discrete, nanoliter-scale volumes of sample. The digital microfluidic Automaton uses two-dimensional microvalve arrays to combinatorially process nanoliter-scale sample volumes. This programmable system enables rapid integration of diverse assay protocols using a universal processing architecture. Microfabricated emulsion generator array (MEGA) devices integrate actively controlled 3-microvalve pumps to enable on-demand generation of uniform droplets for statistical encapsulation of microbeads and cells. A MEGA device containing 96 channels confers the capability of generating up to 3.4 × 10(6) nanoliter-volume droplets per hour for ultrahigh-throughput detection of rare mutations in a vast background of normal genotypes. These novel digital microfluidic platforms offer significant enhancements in throughput, sensitivity, and programmability for automated sample processing and analysis.

  2. The value of the WISC-IV Digit Span subtest in detecting noncredible performance during pediatric neuropsychological examinations.

    Science.gov (United States)

    Kirkwood, Michael W; Hargrave, David D; Kirk, John W

    2011-08-01

    In adult populations, research on methodologies to identify negative response bias has grown exponentially in the last two decades. Far less work has focused on methods appropriate for children. Although several recent studies have demonstrated the appropriateness of using stand-alone symptom validity tests with younger populations, a near absence of pediatric work has investigated embedded validity indicators. The present study examined the classification value of several scores derived from the WISC-IV Digit Span subtest. The sample consisted of 274 clinically referred mild traumatic brain injury patients aged 8 through 16 years. Fourteen percent of the participants failed both the Medical Symptom Validity Test and Test of Memory Malingering, which was used as the criterion for noncredible effort. For age-corrected scaled scores, a score of ≤5 resulted in the optimal cut-score, yielding sensitivity of 51% and specificity of 96%. For Reliable Digit Span, the optimal cut-score was ≤6, with sensitivity of 51% and specificity of 92%. Although only moderately sensitive, Digit Span scores are likely to have good utility in identifying noncredible performance in relatively high-functioning older children and adolescents. Indeed, classification statistics produced in this pediatric sample compare favorably with those produced in many real-world adult patients.

  3. Physical evaluation of prototype high-performance anti-scatter grids: potential for improved digital radiographic image quality.

    Science.gov (United States)

    Fetterly, Kenneth A; Schueler, Beth A

    2009-01-21

    Grid evaluation for a screen-film x-ray system has typically included independent measurement of the opposing contrast improvement factor and Bucky factor. Neither of these metrics, however, is appropriate when assessing grid performance in a digital imaging environment. For digital radiographic systems, the benefit of an anti-scatter grid is well characterized by the quantum signal-to-noise ratio improvement factor (K(SNR)) provided by the grid. The purpose of this work was to measure K(SNR) of prototype grids designed for use with digital radiographic systems. The prototype grids had 5 mm tall lead septa, fiber interspace material, line rate N = 25 and 36 cm(-1) and ratio r = 15 and 21, respectively. The primary and scatter transmission properties of the grids were measured, and K(SNR) was evaluated over a phantom thickness range of 10-50 cm. To provide a comparison, the K(SNR) of similarly constructed N44r15 and N80r15 grids is also reported. K(SNR) of the prototype grids ranged from 1.4 for the 10 cm phantom to 2.4 for the 50 cm phantom. For the thickest phantom, the SNR improvement factor of the prototype grids was 18-83% higher than that of the N44r15 and N80r15 grids, respectively.

  4. Clinical performance evaluation of total protein measurement by digital refractometry and characterization of non-protein solute interferences.

    Science.gov (United States)

    Hunsaker, Joshua J H; Wyness, Sara P; Snow, Taylor M; Genzen, Jonathan R

    2016-12-01

    Refractometric methods to measure total protein (TP) in serum and plasma specimens have been replaced by automated biuret methods in virtually all routine clinical testing. A subset of laboratories, however, still report using refractometry to measure TP in conjunction with serum protein electrophoresis. The objective of this study was therefore to conduct a modern performance evaluation of a digital refractometer for TP measurement. Performance evaluation of a MISCO Palm Abbe™ digital refractometer was conducted through device familiarization, carryover, precision, accuracy, linearity, analytical sensitivity, analytical specificity, and reference interval verification. Comparison assays included a manual refractometer and an automated biuret assay. Carryover risk was eliminated using a demineralized distilled water (ddH2O) wash step. Precision studies demonstrated overall imprecision of 2.2% CV (low TP pool) and 0.5% CV (high TP pool). Accuracy studies demonstrated correlation to both manual refractometry and the biuret method. An overall positive bias (+5.0%) was observed versus the biuret method. On average, outlier specimens had an increased triglyceride concentration. Linearity was verified using mixed dilutions of: a) low and high concentration patient pools, or b) albumin-spiked ddH2O and high concentration patient pool. Decreased recovery was observed using ddH2O dilutions at low TP concentrations. Significant interference was detected at high concentrations of glucose (>267 mg/dL) and triglycerides (>580 mg/dL). Current laboratory reference intervals for TP were verified. Performance characteristics of this digital refractometer were validated in a clinical laboratory setting. Biuret method remains the preferred assay for TP measurement in routine clinical analyses.

  5. ECCM Performance of the Digital Microwave Radio under Adverse Weather Conditions.

    Science.gov (United States)

    1982-05-01

    idenif by block numb.r) Propagation, rain attenuation, Ku-band, alternate routing, digital microwave radio 2 . ABTRACT (1 4 Power N 01010061 W imF V block...Washington D.C. at 15 GHz 3 2. Coefficient of Fog Attenuation 4 3. Line of Sight Multipath Fading Statistics at 15 GHz 6 4. Transmission Through a film...atmospheric attenuation from water vapor, fog , water film on antennas and in particular from rain. The fade margins necessary to overcome these attenuations

  6. Tactical planning: improving performance for information technology(IT)groups creating digital projects

    Institute of Scientific and Technical Information of China (English)

    Melanie D.MYERS

    2010-01-01

    @@ Good planning and communication are crucial to the digitization process.The originators of project proposals and donors who finance the work are often not technically sophisticated.They may have vastly different expectations of the complexity of the work,what are technically feasible and realistic time frames to achieve acceptable results than does the technical staff that carries out the work.In addition,managers may compete for resources(personnel and scheduling priority)for their projects.This can lead to stress,misunderstandings,and lowered technical staff morale.

  7. Digital design and experimental validation of high-performance real-time OFDM systems

    OpenAIRE

    Font Bach, Josep Oriol

    2013-01-01

    Aquesta tesi doctoral té com a objectiu abordar diversos reptes que es presenten en el disseny digital en banda base per a sistemes de comunicació sense fils moderns i futurs. La ràpida i continua evolució que han experimentat les comunicacions sense fils ha estat promoguda per l’ambiciós objectiu de proveir de serveis omnipresents capaços de garantir un alt rendiment i la fiabilitat dels enllaços de comunicació, tot satisfent el creixent requeriment per a la reutilització eficient de l’atape...

  8. High-performance Analog-to-Digital Converters and Line Drivers

    OpenAIRE

    Nieminen, Tero

    2016-01-01

    Nowadays, a high-speed medium-accuracy analog-to-digital converter (ADC) is required in numerous applications, such as a synthetic aperture radar (SAR) system, wireless local area network (WLAN) receiver, or DVD and Blu-Ray readout. As one of the two main parts, this dissertation presents the design and implementation of wideband high-speed medium-accuracy pipeline ADC as a part of a receiver of a SAR system, implemented in a deep-submicron CMOS process. Technology scaling of modern narrow li...

  9. Performance Improvements and Congestion Reduction for Routing-based Synthesis for Digital Microfluidic Biochips

    DEFF Research Database (Denmark)

    Windh, Skyler; Phung, Calvin; Grissom, Daniel T.

    2017-01-01

    Routing-based synthesis for digital microfluidic biochips yields faster assay execution times compared to module-based synthesis. We show that routing-based synthesis can lead to deadlocks and livelocks in specific cases, and that dynamically detecting them and adjusting the probabilities...... associated with different droplet movements can alleviate the situation. We also introduce methods to improve the efficiency of wash droplet routing during routing-based synthesis, and to support non-reconfigurable modules, such as integrated heaters and detectors. We obtain increases in success rates when...

  10. High performance printed N and P-type OTFTs enabling digital and analog complementary circuits on flexible plastic substrate

    Science.gov (United States)

    Jacob, S.; Abdinia, S.; Benwadih, M.; Bablet, J.; Chartier, I.; Gwoziecki, R.; Cantatore, E.; van Roermund, A. H. M.; Maddiona, L.; Tramontana, F.; Maiellaro, G.; Mariucci, L.; Rapisarda, M.; Palmisano, G.; Coppard, R.

    2013-06-01

    This paper presents a printed organic complementary technology on flexible plastic substrate with high performance N and P-type Organic Thin Film Transistors (OTFTs), based on small-molecule organic semiconductors in solution. Challenges related to the integration of both OTFT types in a common complementary flow are addressed, showing the importance of surface treatments. Stability on single devices and on an elementary complementary digital circuit (ring oscillator) is studied, demonstrating that a robust and reliable flow with high electrical performances can be established for printed organic devices. These devices are used to manufacture several analog and digital building blocks. The design is carried out using a model specifically developed for this technology, and taking into account the parametric variability. High-frequency measurements of printed envelope detectors show improved speed performance, resulting from the high mobility of the OTFTs. In addition, a compact dynamic flip-flop and a low-offset comparator are demonstrated, thanks to availability of both n-type and p-type OTFTs in the technology. Measurement results are in good agreement with the simulations. The circuits presented establish a complete library of building blocks for the realization of a printed RFID tag.

  11. Comparison of visual grading analysis and determination of detective quantum efficiency for evaluating system performance in digital chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Sund, Patrik; Baath, Magnus; Maansson, Lars Gunnar [Department of Radiation Physics, Goeteborg University, 41345 Goeteborg (Sweden); Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, 41345 Goeteborg (Sweden); Kheddache, Susanne [Department of Radiology, Goeteborg University, 41345 Goeteborg (Sweden); Department of Radiology, Sahlgrenska University Hospital, 41345 Goeteborg (Sweden)

    2004-01-01

    A study was conducted to compare physical and clinical system performance in digital chest radiography. Four digital X-ray modalities, two storage-phosphor based systems and two generations of a CCD-based system, were evaluated in terms of both their imaging properties (determination of presampling MTF and DQE) and clinical image quality (grading of the reproduction of anatomical details of 23 healthy volunteers using both absolute and relative visual grading analysis). One of the two storage-phosphor systems performed best in both evaluations and the first generation of the CCD-based system was rated worst; however, the other two systems were ranked differently with the two methods. The newest CCD-based system yielded a higher clinical image quality than the second storage-phosphor system, although the latter presented a DQE substantially higher than the former. The results show that clinical performance cannot be predicted from determinations of DQE alone, and that a system with lower DQE, under the quantum-saturated conditions in chest radiography, can outperform a system with higher DQE if the image processing used on the former is more effective in presenting the information in the image to the radiologist. (orig.)

  12. Frequency Tracking Performance Using a Hyperbolic Digital-Phase Locked Loop for Ka-Band Communication in Rain Fading Channels

    Science.gov (United States)

    Sithamparanathan, Kandeepan; Piesiewicz, Radoslaw

    In this paper we study and present some results on the performances of frequency tracking for Ka-band satellite communications in rain fading channels. The carrier frequency is tracked using a 2nd order hyperbolic phase detector based digital-phase locked loop (D-PLL). The hyperbolic D-PLL has the capability of extending the tracking range compared to the other D-PLL and hence can be designed such that to achieve low phase jitter performance for improved carrier tracking. We present the design and analysis of the D-PLL and show some simulation results on the frequency tracking performance for Ka-band rain fading channel. The results are compared with the non-fading noise only case and comparative analyses are made.

  13. Racing performance of Thoroughbreds with superficial digital flexor tendonitis treated with desmotomy of the accessory ligament of the superficial digital flexor tendon: 332 cases (1989-2003).

    Science.gov (United States)

    Hu, Alaine J; Bramlage, Larry R

    2014-06-15

    To assess postoperative probability of racing, career longevity, and convalescent time in Thoroughbred racehorses with moderate to severe superficial digital flexor tendonitis (SDFT) in the forelimbs treated by desmotomy of the accessory ligament of the superficial digital flexor tendon (ie, superior check ligament desmotomy [SCLD]). Retrospective case series. 332 Thoroughbred racehorses with SDFT consecutively treated by means of SCLD. Medical records and racing records were reviewed to assess return to racing, number of races completed, time to first race, and lifetime performance. The horses were categorized as raced or unraced prior to and after surgery. Descriptive statistics including age and treated limb were also recorded. Of 332 horses, 228 (69%) returned to racing following injury and treatment. Seventy-eight of 118 (66%) horses that had not raced prior to injury and 150 of 214 (70%) horses that had raced prior to injury raced after treatment. Seventeen of 39 (44%) horses ≥ 5 years old raced following injury and treatment and 211 of 293 (72%) horses ≤ 4 years old returned to racing. There was no difference in the percentages of horses returning to racing for 2-, 3-, or 4-year olds. Postoperative infections occurred in 6 of the 332 (2%) horses. Median time to first race for horses that raced after surgery was 302 days (range, 48 to 1,120 days; mean ± SD, 341 ± 153 days), with a median of 8 starts/horse after surgery (range, 1 to 109 starts; mean ± SD, 14 ± 15.8 starts). Of 228 horses that returned to racing, 159 (70%) raced ≥ 5 times after surgery. Sex and treated limb did not have a significant effect on return to racing. However, horses ≥ 5 years old were significantly less likely to return to racing, compared with younger horses. In horses with unilateral SDFT and racing was not significantly different between horses treated bilaterally versus unilaterally. 228 of 332 (69%) horses with SDFT of the forelimb treated with SCLD successfully

  14. Quantitative performance of E-Scribe warehouse in detecting quality issues with digital annotated ECG data from healthy subjects.

    Science.gov (United States)

    Sarapa, Nenad; Mortara, Justin L; Brown, Barry D; Isola, Lamberto; Badilini, Fabio

    2008-05-01

    The US Food and Drug Administration recommends submission of digital electrocardiograms in the standard HL7 XML format into the electrocardiogram warehouse to support preapproval review of new drug applications. The Food and Drug Administration scrutinizes electrocardiogram quality by viewing the annotated waveforms and scoring electrocardiogram quality by the warehouse algorithms. Part of the Food and Drug Administration warehouse is commercially available to sponsors as the E-Scribe Warehouse. The authors tested the performance of E-Scribe Warehouse algorithms by quantifying electrocardiogram acquisition quality, adherence to QT annotation protocol, and T-wave signal strength in 2 data sets: "reference" (104 digital electrocardiograms from a phase I study with sotalol in 26 healthy subjects with QT annotations by computer-assisted manual adjustment) and "test" (the same electrocardiograms with an intentionally introduced predefined number of quality issues). The E-Scribe Warehouse correctly detected differences between the 2 sets expected from the number and pattern of errors in the "test" set (except for 1 subject with QT misannotated in different leads of serial electrocardiograms) and confirmed the absence of differences where none was expected. E-Scribe Warehouse scores below the threshold value identified individual electrocardiograms with questionable T-wave signal strength. The E-Scribe Warehouse showed satisfactory performance in detecting electrocardiogram quality issues that may impair reliability of QTc assessment in clinical trials in healthy subjects.

  15. Games-to-teach or games-to-learn unlocking the power of digital game-based learning through performance

    CERN Document Server

    Chee, Yam San

    2016-01-01

    The book presents a critical evaluation of current approaches related to the use of digital games in education. The author identifies two competing paradigms: that of games-to-teach and games-to-learn. Arguing in favor of the latter, the author advances the case for approaching game-based learning through the theoretical lens of performance, rooted in play and dialog, to unlock the power of digital games for 21st century learning. Drawing upon the author’s research, three concrete exemplars of game-based learning curricula are described and discussed. The challenge of advancing game-based learning in education is addressed in the context of school reform. Finally, future prospects of and educational opportunities for game-based learning are articulated. Readers of the book will find the explication of performance theory applied to game-based learning especially interesting. This work constitutes the author’s original theorization. Readers will derive four main benefits: (1) an explication of the differenc...

  16. Performance analysis of digital watermarkingtechniques in the spatial and DCT domain for still images

    Directory of Open Access Journals (Sweden)

    Ajay Goel

    2010-10-01

    Full Text Available Digital watermarking is a process whereby random information is encoded into an image in such a way that the additional payload is indiscernible to the image observer. In this Paper, three typical watermarking techniques are compared and tested extensively, which not only include the private system, the semi-private system but also the public schemes. The comparisons mainly focus on the evaluation of robustness and visual image quality. The results show that the chosen schemes do not have the same behavior and no method has all desirable characteristics. Consequently, we conclude that evaluation of a watermarking algorithm is difficult without first indicating the context in which it is to be applied.

  17. Backup control airstart performance on a digital electronic engine control-equipped F100-engine

    Science.gov (United States)

    Johnson, J. B.

    1984-01-01

    The air start capability of a backup control (BUC) was tested for a digital electronic engine control (DEEC) equipped F100 engine, which was installed in an F-15 aircraft. Two air start schedules were tested. Using the group 1 start schedule, based on a 40 sec timer, an air speed of 300 knots was required to ensure successful 40 and 25% BUC mode spooldown airstarts. If core rotor speed (N2) was less than 40% a stall would occur when the start bleed closed, 40 sec after initiation of the air start. All jet fuel starter (JFS) assisted air starts were successful with the group 1 start schedule. For the group 2 schedule, the time between pressurization and start bleed closure ranged between 50 sec and 72 sec. Idle rps was lower than the desired 65% for air starts at higher altitudes and lower air speeds.

  18. Quantitative microscopy and nanoscopy of sickle red blood cells performed by wide field digital interferometry

    Science.gov (United States)

    Shaked, Natan T.; Satterwhite, Lisa L.; Telen, Marilyn J.; Truskey, George A.; Wax, Adam

    2011-03-01

    We have applied wide-field digital interferometry (WFDI) to examine the morphology and dynamics of live red blood cells (RBCs) from individuals who suffer from sickle cell anemia (SCA), a genetic disorder that affects the structure and mechanical properties of RBCs. WFDI is a noncontact, label-free optical microscopy approach that can yield quantitative thickness profiles of RBCs and measurements of their membrane fluctuations at the nanometer scale reflecting their stiffness. We find that RBCs from individuals with SCA are significantly stiffer than those from a healthy control. Moreover, we show that the technique is sensitive enough to distinguish classes of RBCs in SCA, including sickle RBCs with apparently normal morphology, compared to the stiffer crescent-shaped sickle RBCs. We expect that this approach will be useful for diagnosis of SCA and for determining efficacy of therapeutic agents.

  19. Blurred digital mammography images: an analysis of technical recall and observer detection performance.

    Science.gov (United States)

    Ma, Wang Kei; Borgen, Rita; Kelly, Judith; Millington, Sara; Hilton, Beverley; Aspin, Rob; Lança, Carla; Hogg, Peter

    2017-03-01

    Blurred images in full-field digital mammography are a problem in the UK Breast Screening Programme. Technical recalls may be due to blurring not being seen on lower resolution monitors used for review. This study assesses the visual detection of blurring on a 2.3-MP monitor and a 5-MP report grade monitor and proposes an observer standard for the visual detection of blurring on a 5-MP reporting grade monitor. 28 observers assessed 120 images for blurring; 20 images had no blurring present, whereas 100 images had blurring imposed through mathematical simulation at 0.2, 0.4, 0.6, 0.8 and 1.0 mm levels of motion. Technical recall rate for both monitors and angular size at each level of motion were calculated. χ(2) tests were used to test whether significant differences in blurring detection existed between 2.3- and 5-MP monitors. The technical recall rate for 2.3- and 5-MP monitors are 20.3% and 9.1%, respectively. The angular size for 0.2- to 1-mm motion varied from 55 to 275 arc s. The minimum amount of motion for visual detection of blurring in this study is 0.4 mm. For 0.2-mm simulated motion, there was no significant difference [χ(2) (1, N = 1095) = 1.61, p = 0.20] in blurring detection between the 2.3- and 5-MP monitors. According to this study, monitors ≤2.3 MP are not suitable for technical review of full-field digital mammography images for the detection of blur. Advances in knowledge: This research proposes the first observer standard for the visual detection of blurring.

  20. Free software for performing physical analysis of systems for digital radiography and mammography

    Energy Technology Data Exchange (ETDEWEB)

    Donini, Bruno; Lanconelli, Nico, E-mail: nico.lanconelli@unibo.it [Alma Mater Studiorum, Department of Physics and Astronomy, University of Bologna, Bologna 40127 (Italy); Rivetti, Stefano [Fisica Medica, Ospedale di Sassuolo S.p.A., Sassuolo 41049 (Italy); Bertolini, Marco [Medical Physics Unit, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia 42123 (Italy)

    2014-05-15

    Purpose: In this paper, the authors present a free software for assisting users in achieving the physical characterization of x-ray digital systems and image quality checks. Methods: The program was developed as a plugin of a well-known public-domain suite ImageJ. The software can assist users in calculating various physical parameters such as the response curve (also termed signal transfer property), modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE). It also includes the computation of some image quality checks: defective pixel analysis, uniformity, dark analysis, and lag. Results: The software was made available in 2009 and has been used during the last couple of years by many users who gave us valuable feedback for improving its usability. It was tested for achieving the physical characterization of several clinical systems for digital radiography and mammography. Various published papers made use of the outcomes of the plugin. Conclusions: This software is potentially beneficial to a variety of users: physicists working in hospitals, staff working in radiological departments, such as medical physicists, physicians, engineers. The plugin, together with a brief user manual, are freely available and can be found online ( http://www.medphys.it/downloads.htm ). With our plugin users can estimate all three most important parameters used for physical characterization (MTF, NPS, and also DQE). The plugin can run on any operating system equipped with ImageJ suite. The authors validated the software by comparing MTF and NPS curves on a common set of images with those obtained with other dedicated programs, achieving a very good agreement.

  1. Performance of a Downconverter Test-electronics with MTCA-based Digitizers for Beam Position Monitoring in 3.9 GHz Accelerating Cavities

    CERN Document Server

    Wamsat, T; Lorbeer, B; Zhang, P

    2012-01-01

    Beam-excited higher order modes (HOM) in 3.9GHz accelerating cavities are planned to be used for beam position monitoring at the European XFEL. The selected HOMs are located around 5440MHz, with a bandwidth of 100MHz and 9060MHz, with a bandwidth of 50MHz. A downconverter electronics, built for tests at FLASH, converts the HOMs to an intermediate frequency of 70MHz. The MTCA (Micro Telecommunications Computing Architecture) standard will be used for the XFEL. Thus it is important to have a performance study of the downconverter test-electronics using the MTCA digitizer card SIS8300. In the digitizer the IF frequency of 70MHz is undersampled with a clock frequency of 108MS/s. The paper presents the performance of the digitizer together with the test-electronics. A comparison with a 216MS/s VME (Versa Module Eurocard) digitizer is made.

  2. Digital Implementation of Method for Discontinuous Current Mode Compensation Of High-Performance Line-Commutated Converters

    CERN Document Server

    Maestri, S; Uicich, G; Gomez Costa, J; Petrocelli, R; CERN. Geneva. TE Department

    2010-01-01

    Many high-performance power converters at CERN are implemented with thyristors, mostly in CCM (Continuous Conduction Mode) due to their better dynamic response. In DCM (Discontinuous Conduction Mode), the converter reduces its small-signal gain, producing a degraded time response which can lead to instability. Several of these converters use digital regulation, allowing the implementation of complex non- linear control techniques. Therefore, a strategy to control the converters in DCM (Discontinuous Conduction Mode) can be implemented, bearing in mind that their standard operation (sampling time, measured signals, acquisition system) can not be drastically changed. This report presents the implementation of a new method to control line-commutated converters in discontinuous conduction mode (DCM). The method is based on the modfication of the thyristor's ring angle _ using a linear approximation, yielding nearly the same dynamic performance as in continuous conduction mode. The _ring angle is corrected by addi...

  3. Digital Signal Processing using Stream High Performance Computing: A 512-input Broadband Correlator for Radio Astronomy

    CERN Document Server

    Kocz, J; Barsdell, B R; Price, D; Bernardi, G; Bourke, S; Clark, M A; Craig, J; Dexter, M; Dowell, J; Eftekhari, T; Ellingson, S; Hallinan, G; Hartman, J; Jameson, A; MacMahon, D; Taylor, G; Schinzel, F; Werthimer, D

    2014-01-01

    A "large-N" correlator that makes use of Field Programmable Gate Arrays and Graphics Processing Units has been deployed as the digital signal processing system for the Long Wavelength Array station at Owens Valley Radio Observatory (LWA-OV), to enable the Large Aperture Experiment to Detect the Dark Ages (LEDA). The system samples a ~100MHz baseband and processes signals from 512 antennas (256 dual polarization) over a ~58MHz instantaneous sub-band, achieving 16.8Tops/s and 0.236 Tbit/s throughput in a 9kW envelope and single rack footprint. The output data rate is 260MB/s for 9 second time averaging of cross-power and 1 second averaging of total-power data. At deployment, the LWA-OV correlator was the largest in production in terms of N and is the third largest in terms of complex multiply accumulations, after the Very Large Array and Atacama Large Millimeter Array. The correlator's comparatively fast development time and low cost establish a practical foundation for the scalability of a modular, heterogeneo...

  4. Performance Optimization of Fujian Digital Design and Manufacture Service Platform Based on AJAX

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiaolin; GAO Chenghui; HE Bingwei

    2006-01-01

    In this paper, the problem on the service platform, which existed on the traditional WEB application mode, are analyzed in detail. It shows that application of the AJAX technology can optimize the service platform. And the AJAX technology can supply the wonderful solution for the development of the high-performance WEB application by means of the WEB performance testing tool to test the network performance of the service platform.

  5. A New High-Performance Digital FM Modulator and Demodulator for Software-Defined Radio and Its FPGA Implementation

    Directory of Open Access Journals (Sweden)

    Indranil Hatai

    2011-01-01

    Full Text Available This paper deals with an FPGA implementation of a high performance FM modulator and demodulator for software defined radio (SDR system. The individual component of proposed FM modulator and demodulator has been optimized in such a way that the overall design consists of a high-speed, area optimized and low-power features. The modulator and demodulator contain an optimized direct digital frequency synthesizer (DDFS based on quarter-wave symmetry technique for generating the carrier frequency with spurious free dynamic range (SFDR of more than 64 dB. The FM modulator uses pipelined version of the DDFS to support the up conversion in the digital domain. The proposed FM modulator and demodulator has been implemented and tested using XC2VP30-7ff896 FPGA as a target device and can operate at a maximum frequency of 334.5 MHz and 131 MHz involving around 1.93 K and 6.4 K equivalent gates for FM modulator and FM demodulator respectively. After applying a 10 KHz triangular wave input and by setting the system clock frequency to 100 MHz using Xpower the power has been calculated. The FM modulator consumes 107.67 mW power while FM demodulator consumes 108.67 mW power for the same input running at same data rate.

  6. Initial PET Performance Evaluation of a Preclinical Insert for PET/MRI with Digital SiPM Technology

    CERN Document Server

    Schug, David; Weissler, Bjoern; Gebhardt, Pierre; Goldschmidt, Benjamin; Wehner, Jakob; Dueppenbecker, Peter Michael; Salomon, Andre; Hallen, Patrick; Kiessling, Fabian; Schulz, Volkmar

    2015-01-01

    Hyperion-IID is a positron emission tomography (PET) insert which allows simultaneous operation in a clinical magnetic resonance imaging (MRI) scanner. To read out the scintillation light of the employed LYSO crystal arrays with a pitch of 1 mm pitch and 12 mm in height, digital silicon photomultipliers (DPC 3200-22, Philips Digital Photon Counting) (DPC) are used. The basic PET performance in terms of energy resolution, coincidence resolution time (CRT) and sensitivity as a function of operating parameters, such as the operating temperature, the applied overvoltage, activity and configuration parameters of the DPCs, were evaluated on system level. The measured energy resolution did not show a large dependency on the selected parameters and is in the range of 12.4-12.9% for low activities and degrades to ~13.6% at activities of ~100 MBq. The CRT strongly depends on the selected trigger scheme (trig) of the DPCs. We measured approximately 260 ps, 440 ps, 540 ps and 1300 ps for trig 1-4, respectively. The trues...

  7. Performance seeking control (PSC) for the F-15 highly integrated digital electronic control (HIDEC) aircraft

    Science.gov (United States)

    Orme, John S.

    1995-01-01

    The performance seeking control algorithm optimizes total propulsion system performance. This adaptive, model-based optimization algorithm has been successfully flight demonstrated on two engines with differing levels of degradation. Models of the engine, nozzle, and inlet produce reliable, accurate estimates of engine performance. But, because of an observability problem, component levels of degradation cannot be accurately determined. Depending on engine-specific operating characteristics PSC achieves various levels performance improvement. For example, engines with more deterioration typically operate at higher turbine temperatures than less deteriorated engines. Thus when the PSC maximum thrust mode is applied, for example, there will be less temperature margin available to be traded for increasing thrust.

  8. Experimental Research of Variable Operating Performance on Water Source Multi-Connected Air-Conditioning System with Digital Scroll Compressor

    Directory of Open Access Journals (Sweden)

    Xingwang Zhu

    2013-05-01

    Full Text Available In this study, we study the water source heat pump and digital scroll compressor and experimentally in the multi-connected air-conditioning system. Variable performance is developed when the unit operates in refrigerating and heating mode. The maximum of refrigerating capacity is 36519.95W when inlet water temperature of the condenser is 30°C and dry-bulb temperature of indoor air is 32°C, at the same time the maximum of EER is 4.33 when inlet water temperature of the condenser is 20°C and dry-bulb temperature of indoor air is 27°C. The unit operates in heating mode, the maximum of heating capacity and EER is 33275.73W and 3.86 when inlet water temperature of the condenser is 30°C and dry-bulb temperature of indoor air is 20°C.

  9. Improvement of image performance in digital breast tomosynthesis (DBT) by incorporating a compressed-sensing (CS)-based deblurring scheme

    Science.gov (United States)

    Kim, Kyuseok; Park, Yeonok; Cho, Heemoon; Cho, Hyosung; Je, Uikyu; Park, Chulkyu; Lim, Hyunwoo; Park, Soyoung; Woo, Taeho; Choi, Sungil

    2016-10-01

    In this work, we investigated a compressed-sensing (CS)-based deblurring scheme incorporated with the total-variation (TV) regularization penalty for image deblurring of high accuracy and adopted it into the image reconstruction in conventional digital breast tomosynthesis (DBT). We implemented the proposed algorithm and performed a systematic simulation to demonstrate its viability for improving the image performance in DBT as well as two-dimensional (2D) mammography. In the simulation, blurred noisy projection images of a 3D numerical breast phantom were generated by convolving their original (or exact) version by a designed 2D Gaussian filter kernel (standard deviation=2 in pixel unit, kernel size=11×11), followed by adding Gaussian noise (mean=0, variance=0.05), and deblurred by using the algorithm before performing the DBT reconstruction procedure. Here the projection images were taken with a half tomographic angle of θ=20° and an angle step of Δθ=2°. We investigated the image performance of the reconstructed DBT images quantitatively in terms of the modulation and the slice-sensitive profile (SSP).

  10. Evaluation of automatic exposure control performance in full-field digital mammography systems using contrast-detail analysis

    Science.gov (United States)

    Suarez Castellanos, Ivan M.; Kaczmarek, Richard; Brunner, Claudia C.; de Las Heras, Hugo; Liu, Haimo; Chakrabarti, Kish

    2012-03-01

    Full Field Digital Mammography (FFDM) is increasingly replacing screen-film systems for screening and diagnosis of breast abnormalities. All FFDM systems are equipped with an Automatic Exposure Control (AEC) which automatically selects technique factors to optimize dose and image quality. It is therefore crucial that AEC performance is properly adjusted and optimized to different breast thicknesses. In this work, we studied the AEC performance of three widely used FFDM systems using the CDMAM and QUART mam/digi phantoms. We used the CDMAM phantom to generate Contrast-Detail (C-D) curves for each AEC mode available in the FFDM systems under study for phantoms with equivalent X-Ray attenuation properties as 3.2 cm, 6 cm and 7.5 cm thick breasts. Generated C-D curves were compared with ideal C-D curves constructed using a metric referred to as the k-factor which is the product of the thickness and the diameter of the smallest correctly identified disks in the CDMAM phantom. Previous observer studies have indicated that k-factor values of 60 to 80 μm2 are particularly useful in demonstrating the threshold for object detectability for detectors used in digital mammography systems. The QUART mam/digi phantom was used to calculate contrast-to-noise ratio (CNR) values at different phantom thicknesses. The results of the C-D analysis and CNR measurements were used to determine limiting CNR values intended to provide a threshold for proper image quality assessment. The results of the Contrast-Detail analysis show that for two of the three evaluated FFDM systems, at higher phantom thicknesses, low contrast signal detectability gets worse. This agrees with the results obtained with the QUART mam/digi phantom, where CNR decreases below determined limiting CNR values.

  11. Digital breast tomosynthesis versus mammography and breast ultrasound: a multireader performance study

    Energy Technology Data Exchange (ETDEWEB)

    Thibault, Fabienne; Malhaire, Caroline; Tardivon, Anne [Department of Radiology, Paris Cedex 05 (France); Dromain, Clarisse; Balleyguier, Corinne S. [Institut de cancerologie Gustave-Roussy, Department of Radiology, Villejuif (France); Breucq, Catherine [Universitair Ziekenhuis-VUB, Department of Radiology, Bruxelles (Belgium); Steyaert, Luc [Department of Radiology, Brugge (Belgium); Baldan, Enrica [Veneto Institute of Oncology (IOV)-IRCCS, Department of Radiology, Padua (Italy); Drevon, Harir [Numerus Ltd, Lyon (France)

    2013-09-15

    To compare the diagnostic performance of single-view breast tomosynthesis (BT) with that of dual-view mammography (MX); to assess the benefit of adding the craniocaudal (CC) mammographic view to BT, and of adding BT to MX plus breast ultrasound, considered to be the reference work-up. One hundred and fifty-five consenting patients with unresolved mammographic and/or ultrasound findings or breast symptoms underwent conventional work-up plus mediolateral oblique-view BT of the affected breast. The final study set in 130 patients resulted in 55 malignant and 76 benign and normal cases. Seven breast radiologists rated the cases through five sequential techniques using a BIRADS-based scale: MX, MX + ultrasound, MX + ultrasound + BT, BT, BT + MX(CC). Multireader, multicase receiver operating characteristic (ROC) analysis was performed and performance of the techniques was assessed from the areas under ROC curves. The performance of BT and of BT + MX(CC) was tested versus MX; the performance of MX + ultrasound + BT tested versus MX + ultrasound. Tomosynthesis was found to be non-inferior to mammography. BT + MX(CC) did not appear to be superior to MX, and MX + ultrasound + BT not superior to MX + ultrasound. Overall, none of the five techniques tested outperformed the others. Further clinical studies are needed to clarify the role of BT as a substitute for traditional work-up in the diagnostic environment. (orig.)

  12. THE DIGITAL ARCHIVING SYSTEM WITH TWITTER FOR LOCAL TRADITIONAL PERFORMING ARTS BY CITIZEN PARTICIPATION

    Directory of Open Access Journals (Sweden)

    Chiho Yoshida

    2011-12-01

    Full Text Available Local communities in mountainous and coast villages in Japan are facing problems related to aging and depopulation that discourage efforts to keep the traditional performing arts in the local community. The purpose of this study is to design an ―Archive and Community‖ model that creates a relationship between local citizens and non-citizens to keep the traditional performing arts in the local community by combining the traditional archiving system with social media like Twitter. This paper describes the experimental data results and discussions using the ―Archive and Community System‖ prototype.

  13. Performance of the CMS Tracker Optical Links and Future Upgrade Using Bandwidth Efficient Digital Modulation

    CERN Document Server

    Dris, Stefanos; Troska, J

    2006-01-01

    The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) particle accelerator will begin operation in 2007. The innermost CMS subdetector, the Tracker, comprises ~10 million detector channels read out by ~40 000 analog optical links. The optoelectronic components have been designed to meet the stringent requirements of a high energy physics (HEP) experiment in terms of radiation hardness, low mass and low power. Extensive testing has been performed on the components and on complete optical links in test systems. Their functionality and performance in terms of gain, noise, linearity, bandwidth and radiation hardness is detailed. Particular emphasis is placed on the gain, which directly affects the dynamic range of the detector data. It has been possible to accurately predict the variation in gain that will be observed throughout the system. A simulation based on production test data showed that the average gain would be ~38% higher than the design target at the Tracker operating temperatur...

  14. Practical Testing and Performance Analysis of Phasor Measurement Unit Using Real Time Digital Simulator (RTDS)

    DEFF Research Database (Denmark)

    Liu, Leo; Rather, Zakir Hussain; Stearn, Nathen

    2012-01-01

    visualisation and post event analysis of power systems. It is expected however, that through integration with traditional Supervisory Control and Data Acquisition (SCADA) systems, closed loop control applications will be possible. Phasor Measurement Units (PMUs) are fundamental components of WAMS. Large WAMS......Wide Area Measurement Systems (WAMS) and Wide Area Monitoring, Protection and Control Systems (WAMPACS) have evolved rapidly over the last two decades [1]. This fast emerging technology enables real time synchronized monitoring of power systems. Presently, WAMS are mainly used for real time...... may support PMUs from multiple manufacturers and therefore it is important that there is a way of standardising the measurement performance of these devices. Currently the IEEE Standard C37.118 is used to quantify the measurement performance of PMUs. While standard specifications are also available...

  15. Elastic matching of very large digital images on high performance clusters

    CERN Document Server

    Modersiteki, J; Schmitt, O M; Lustig, G

    1999-01-01

    The aim of the human neuroscanning project is to build an atlas of the human brain, based on a variety of image modalities in particular histological sections of a prepared brain. Reconstructing essential information out of deformed images is a key problem. We describe a method to correct elastic deformations. Since the method is computationally expensive a parallel implementation is presented. The measurements and results shown are performed on a cluster of 48 Pentium II PCs connected via Myrinet. (17 refs).

  16. L-Band Digital Aeronautical Communications System Engineering - Concepts of Use, Systems Performance, Requirements, and Architectures

    Science.gov (United States)

    Zelkin, Natalie; Henriksen, Stephen

    2010-01-01

    This NASA Contractor Report summarizes and documents the work performed to develop concepts of use (ConUse) and high-level system requirements and architecture for the proposed L-band (960 to 1164 MHz) terrestrial en route communications system. This work was completed as a follow-on to the technology assessment conducted by NASA Glenn Research Center and ITT for the Future Communications Study (FCS). ITT assessed air-to-ground (A/G) communications concepts of use and operations presented in relevant NAS-level, international, and NAS-system-level documents to derive the appropriate ConUse relevant to potential A/G communications applications and services for domestic continental airspace. ITT also leveraged prior concepts of use developed during the earlier phases of the FCS. A middle-out functional architecture was adopted by merging the functional system requirements identified in the bottom-up assessment of existing requirements with those derived as a result of the top-down analysis of ConUse and higher level functional requirements. Initial end-to-end system performance requirements were derived to define system capabilities based on the functional requirements and on NAS-SR-1000 and the Operational Performance Assessment conducted as part of the COCR. A high-level notional architecture of the L-DACS supporting A/G communication was derived from the functional architecture and requirements.

  17. Performance of swarm based optimization techniques for designing digital FIR filter: A comparative study

    Directory of Open Access Journals (Sweden)

    I. Sharma

    2016-09-01

    Full Text Available In this paper, a linear phase FIR filter is designed through recently proposed nature inspired optimization algorithm known as Cuckoo search (CS. A comparative study of Cuckoo search (CS, particle swarm optimization (PSO and artificial bee colony (ABC nature inspired optimization methods in the field of linear phase FIR filter design is also presented. For this purpose, an improved L1 weighted error function is formulated in frequency domain, and minimized through CS, PSO and ABC respectively. The error or objective function has a controlling parameter wt which controls the amount of ripple in the desired band of frequency. The performance of FIR filter is examined through three key parameters; Maximum Pass Band Ripple (MPR, Maximum Stopband Ripple (MSR and Stopband Attenuation (As. Comparative study and the simulation results reveal that the designed filter with CS gives better performance in terms of Maximum Stopband Ripple (MSR, and Stopband Attenuation (As for low order filter design, and for higher order it also gives better performance in term of Maximum Passband Ripple (MPR. Superiority of the proposed technique is also shown through comparison with other recently proposed methods.

  18. Improved performance of hybrid error control techniques for real-time digital communications over noisy channels

    Science.gov (United States)

    Yang, Charlie Qing

    1993-06-01

    Delay-related performance characteristics are investigated for asynchronous time division multiplexing links. Two methods based on an imbedded Markov chain model are developed and applied to the system with a noisy feedback channel yielding analytical expressions for the buffer occupancy and the block delay. A recursive expression for packet loss probability for systems with a finite transmitter buffer is obtained. The concept of delay limited error control coding is introduced for real-time communications. Performance improvement by truncation of a type-2 hybrid automatic repeat-request (ARQ) protocol with one retransmission is examined showing that the truncated protocol has a bounded delay and bounded queue length under typical conditions. The error performance of the truncated protocol is further analyzed for various mobile fading channels. Matched rate hybrid error control coding for both adaptive and non-adaptive cases is also studied. A new adaptive error control protocol using Reed-Solomon codes is proposed using novel feedback transmissions to achieve faster estimation of channel states. Numerical optimization is carried out by introducing overall and modified throughput as efficiency criteria. Based on channel bit error rate measurement, optimum overall throughput is obtained with minimum implementation complexity.

  19. A High Performance Digital Time Interval Spectrometer: An Embedded, FPGA-Based System With Reduced Dead Time Behaviour

    Directory of Open Access Journals (Sweden)

    Arkani Mohammad

    2015-12-01

    Full Text Available In this work, a fast 32-bit one-million-channel time interval spectrometer is proposed based on field programmable gate arrays (FPGAs. The time resolution is adjustable down to 3.33 ns (= T, the digitization/discretization period based on a prototype system hardware. The system is capable to collect billions of time interval data arranged in one million timing channels. This huge number of channels makes it an ideal measuring tool for very short to very long time intervals of nuclear particle detection systems. The data are stored and updated in a built-in SRAM memory during the measuring process, and then transferred to the computer. Two time-to-digital converters (TDCs working in parallel are implemented in the design to immune the system against loss of the first short time interval events (namely below 10 ns considering the tests performed on the prototype hardware platform of the system. Additionally, the theory of multiple count loss effect is investigated analytically. Using the Monte Carlo method, losses of counts up to 100 million events per second (Meps are calculated and the effective system dead time is estimated by curve fitting of a non-extendable dead time model to the results (τNE = 2.26 ns. An important dead time effect on a measured random process is the distortion on the time spectrum; using the Monte Carlo method this effect is also studied. The uncertainty of the system is analysed experimentally. The standard deviation of the system is estimated as ± 36.6 × T (T = 3.33 ns for a one-second time interval test signal (300 million T in the time interval.

  20. Implementation of real-time SAR systems with a high-performance digital signal processor

    Science.gov (United States)

    Kloos, Helge; Wittenburg, Jens P.; Hinrichs, Willm; Lieske, Hanno; Pirsch, Peter

    1999-12-01

    Real-time Synthetic Aperture Radar (SAR) image synthesis is one of the major problems to solve in the future. To achieve a fully synthesized SAR image, the raw signal must be filtered with a 2-dimensional function representing the system transfer function. These filtering operations are usually processed by multiplication in frequency domain. Therefore, the Fast Fourier Transform (FFT) used for transformation to/from frequency domain is the predominant algorithm in terms of processing power for SAR image synthesis. The presented HiPAR- DSP is a programmable architecture, which is optimized for FFT-dominated applications like SAR image processing. To provide the high requested processing power for these task, the HiPAR-DSP has an array of 4 (HiPAR-DSP4) respectively 16 (HiPAR-DSP16) parallel processing units (datapaths) which is controlled by a single RISC Controller. For data exchange between the processing units there is a shared memory which allows the concurrent access from all processing units in a single clock cycle. So the HiPAR-DSP16 performs a complex FFT with 1024 Samples in 32microsecond(s) . For the implemented SAR- Processing task, the Range Compression with 4096 complex samples per line we achieve a real-time performance of nearly 1500 rangelines/s.

  1. Dynamic SVL and body bias for low leakage power and high performance in CMOS digital circuits

    Science.gov (United States)

    Deshmukh, Jyoti; Khare, Kavita

    2012-12-01

    In this article, a new complementary metal oxide semiconductor design scheme called dynamic self-controllable voltage level (DSVL) is proposed. In the proposed scheme, leakage power is controlled by dynamically disconnecting supply to inactive blocks and adjusting body bias to further limit leakage and to maintain performance. Leakage power measurements at 1.8 V, 75°C demonstrate power reduction by 59.4% in case of 1 bit full adder and by 43.0% in case of a chain of four inverters using SVL circuit as a power switch. Furthermore, we achieve leakage power reduction by 94.7% in case of 1 bit full adder and by 91.8% in case of a chain of four inverters using dynamic body bias. The forward body bias of 0.45 V applied in active mode improves the maximum operating frequency by 16% in case of 1 bit full adder and 5.55% in case of a chain of inverters. Analysis shows that additional benefits of using the DSVL and body bias include high performance, low leakage power consumption in sleep mode, single threshold implementation and state retention even in standby mode.

  2. On the Performance Analysis of Digital Communication Systems Perturbed by Non-Gaussian Noise and Interference

    KAUST Repository

    Soury, Hamza

    2016-06-29

    The Gaussian distribution is typically used to model the additive noise affecting communication systems. However, in many cases the noise cannot be modeled by a Gaussian distribution. In this thesis, we investigate the performance of different communication systems perturbed by non-Gaussian noise. Three families of noise are considered in this work, namely the generalized Gaussian noise, the Laplace noise/interference, and the impulsive noise that is modeled by an α-stable distribution. More specifically, in the first part of this thesis, the impact of an additive generalized Gaussian noise is studied by computing the average symbol error rate (SER) of one dimensional and two dimensional constellations in fading environment. We begin by the simple case of two symbols, i.e. binary phase shift keying (BPSK) constellation. From the results of this constellation, we extended the work to the average SER of an M pulse amplitude modulation (PAM). The first 2 − D constellation is the M quadrature amplitude modulation (QAM) (studied for two geometric shapes, namely square and rectangular), which is the combination of two orthogonal PAM signals (in-phase and quadrature phase PAM). In the second part, the system performance of a circular constellation, namely M phase shift keying (MPSK) is studied in conjunction with a Laplace noise with independent noise components. A closed form and an asymptotic expansion of the SER are derived for two detectors, maximum likelihood and minimum distance detectors. Next, we look at the intra cell interference of a full duplex cellular network which is shown to follow a Laplacian distribution with dependent, but uncorrelated, complex components. The densities of that interference are expressed in a closed form in order to obtain the SER of several communication systems (BPSK, PAM, QAM, and MPSK). Finally, we study the statistics of the α-stable distribution. Those statistics are expressed in closed form in terms of the Fox H function and

  3. Performance analysis of general purpose and digital signal processor kernels for heterogeneous systems-on-chip

    Directory of Open Access Journals (Sweden)

    T. von Sydow

    2003-01-01

    Full Text Available Various reasons like technology progress, flexibility demands, shortened product cycle time and shortened time to market have brought up the possibility and necessity to integrate different architecture blocks on one heterogeneous System-on-Chip (SoC. Architecture blocks like programmable processor cores (DSP- and GPP-kernels, embedded FPGAs as well as dedicated macros will be integral parts of such a SoC. Especially programmable architecture blocks and associated optimization techniques are discussed in this contribution. Design space exploration and thus the choice which architecture blocks should be integrated in a SoC is a challenging task. Crucial to this exploration is the evaluation of the application domain characteristics and the costs caused by individual architecture blocks integrated on a SoC. An ATE-cost function has been applied to examine the performance of the aforementioned programmable architecture blocks. Therefore, representative discrete devices have been analyzed. Furthermore, several architecture dependent optimization steps and their effects on the cost ratios are presented.

  4. Performance of a carbon nanotube field emission X-ray source array for stationary digital breast tomosynthesis

    Science.gov (United States)

    Gidcumb, Emily Morgan

    This work describes the performance of a stationary digital breast tomosynthesis (s-DBT) X-ray tube based on carbon nanotube (CNT) cathodes, and the imaging system developed around it. The s-DBT system has the potential to improve the detection and diagnosis of breast cancer over commercially available digital breast tomosynthesis (DBT) systems. DBT is growing in popularity in the United States, and around the world, as a potential replacement for traditional 2D mammography. The main advantage of DBT over 2D mammography lies in the pseudo-3D nature of the technique allowing the removal of overlapping breast tissue within the image. s-DBT builds on this advantage by removing blur from focal spot motion. Introductions to breast imaging techniques and the DBT modality are given, followed by an introduction to carbon nanotube field emission, the foundation of the s-DBT technology. Details of the s-DBT X-ray tube design and system integration are discussed including specific design parameters, system requirements, and the development process. Also included are summaries of the X-ray tube and system performance over time, and results from characterization measurements. Specific focus is given to the development and completion of a fabrication procedure for tungsten gate mesh, characterization of the CNT cathodes, and improving the system's spatial resolution with use of the focusing electrodes. The tungsten gate mesh is an essential component for extracting electrons from CNTs. A successful deep reactive ion etching fabrication procedure was developed, and the improved gate mesh allowed for higher cathode current and longer pulse widths to be employed in the s-DBT system. Characterization of the CNT cathodes revealed their high-current capacity and the ability to produce relatively long pulse widths, mimicking a 2D imaging modality. This work confirmed that the cathodes are well suited for the task of breast imaging, and explored possible improvements. Lastly, it was

  5. Event related potentials to digit learning: Tracking neurophysiologic changes accompanying recall performanceModelling of auditory evoked potentials of human sleep-wake states

    NARCIS (Netherlands)

    Jongsma, M.L.A.; Gerrits, N.J.H.M.; Rijn, C.M. van; Quiroga, R.Q.; Maes, J.H.R.

    2012-01-01

    The aim of this study was to track recall performance and event-related potentials (ERPs) across multiple trials in a digit-learning task. When a sequence is practiced by repetition, the number of errors typically decreases and a learning curve emerges. Until now, almost all ERP learning and memory

  6. Evaluation of PET performance and MR compatibility of a preclinical PET/MR insert with digital silicon photomultiplier technology

    Energy Technology Data Exchange (ETDEWEB)

    Hallen, Patrick; Schug, David; Wehner, Jakob [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany); Weissler, Bjorn [Department of Chemical Application Research, Philips Research (Germany); Gebhardt, Pierre [Division of Imaging Sciences and Biomedical Engineering, King’s College London (United Kingdom); Goldschmidt, Benjamin [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany); Salomon, Andre [Department of Oncology Solutions, Philips Research (Germany); Duppenbecker, Peter [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany); Kiessling, Fabian [Institute for Experimental Molecular Imaging, RWTH Aachen University (Germany); Schultz, Volkmar [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany)

    2015-05-18

    In this work we present detailed characterizations of our preclinical high resolution PET/MR insert based on the Hyperion-IID platform. The PET/MR insert consists of a ring of 10 singles detection modules, each comprising 2x3 scintillation detector stacks. Each detector stack features a 30x30 pixelated LYSO crystal array with a height of 12 mm and a pitch of 1 mm, coupled via a slit 2 mm light guide to a digital SiPM tile. The PET performance is stable under a wide range of operating points. The spatial resolution is below 1Ä,mm and the CRT reaches 260 or 450 ps depending on trigger settings. The energy resolution is 12.6% FWHM. The characterization of the MR compatibility showed no relevant degradation in PET performance during MRI operation. On the MRI side, we observe a degradation in B0 homogeneity from a VRMS of 0.03 ppm to 0.08 ppm with active shimming, while observing only minor degradations in the B0 field. The noise floor is slightly increased by 2-15% without any observable dependence on the activity. The Z gradients induces an observable eddy current inside the PET inserts which can lead to ghosting artifacts for EPI sequences. However, we don't observe any visible image degradation for widely used anatomical imaging sequences such as gradient echo and turbo spin echo sequences. To prove the viability of our PET/MR insert for in vivo small animal studies, we successfully performed a longitudinal mouse study with subcutaneously injected tumor model cells. The simultaneously acquired PET/MR images provide a high level of anatomical information and soft tissue contrast in the MR layer together with a high resolution image of the FDG tracer distribution in the PET layer.

  7. Digital gaming expertise

    DEFF Research Database (Denmark)

    Toft-Nielsen, Claus

    , to have access to the dynamic power systems in and around digital games theorized as ‘gaming capital’ (Consalvo, 2007) and who cannot? I argue, in other words, for an understanding of digital gaming competence as a reflection, negotiation, and production of gendered power relations, performed in ways......In a digitally saturated environment digital media users of all kinds, engaged in different areas of activity, are increasingly categorized in terms of their ability to appropriate and use digital media – they are regarded as non-users, experts, natives, or literates for instance. Within...... communication and game studies there are multiple understandings of how digital expertise is expressed and performed, and subsequently how these expressions and performances can be valued, understood and theorized within the research community. Among other things expertise with and within digital games has...

  8. Durability Analysis and Experimental Validation of Environmental Barrier Coating (EBC Performance Using Combined Digital Image Correlation and NDE

    Directory of Open Access Journals (Sweden)

    Ali Abdul-Aziz

    2016-12-01

    Full Text Available To understand the failure mechanism or to predict the spallation life of environmental barrier coatings (EBC on fiber reinforced ceramic matrix composites, the fracture strength of EBC and the process of the crack growth in EBC layers need to be experimentally determined under standard or simulated engine operating conditions. The current work considers a multi layered barium strontium aluminum silicate (BSAS-based EBC-coated, melt infiltrated silicon carbide fiber reinforced silicon carbide matrix composite (MI SiC/SiC specimen that was tensile tested at room temperature. Numerous tests were performed under tensile loading conditions, and the specimen was loaded until failure under pre-determined stress levels. The specimen was examined with optical microscopy, scanning electron microscopy (SEM, computed tomography (CT scan, and digital image correlation (DIC camera. Observation from the computed tomography scanning, the SEM, and the optical microscopy did not offer conclusive information concerning the cracks that spawned during the tests. However, inspection with the DIC camera offered some indication that cracks had developed and allowed their detection and the location of their initiation site. Thus, this study provides detailed discussion of the results obtained from the experimental investigation and the nondestructive evaluation (NDE, and it also includes assessment of the stress response predicted by analytical modeling and their impact on EBC durability and crack growth formation under complex loading settings.

  9. Design of linear anti-scatter grid geometry with optimum performance for screen-film and digital mammography systems.

    Science.gov (United States)

    Khodajou-Chokami, H; Sohrabpour, M

    2015-08-01

    A detailed 3D Monte Carlo simulation of the grid geometrical parameters in screen-film mammography (SFM) and digital mammography (DM) systems has been performed. A combination of IEC 60627:2013 international standard conditions and other more clinically relevant parameters were used for this simulation. Accuracy of our results has been benchmarked with previously published data and good agreement has been obtained. Calculations in a wide range of linear anti-scatter grid geometries have been carried out. The evaluated parameters for the SFM system were the Bucky factor (BF) and contrast improvement factor (CIF) and for the DM system it was signal difference-to-noise ratio improvement factor (SIF). The CIF parameter was chosen to be nearly the same as the commercial grade, the BF and SIF were significantly improved compared to commercial grids in use today. Our optimized grid parameters for the SFM system were lead strip thickness d = 12 µm, grid ratio r = 5 and strip density N = 65 lines/cm. And for the DM system these parameters were d = 5 µm, r = 3 and N = 100 lines/cm. Both optimized grid sets have thinner d and higher N compared to the commercial grids.

  10. Benchmarking the performance of fixed-image receptor digital radiographic systems part 1: a novel method for image quality analysis.

    Science.gov (United States)

    Lee, Kam L; Ireland, Timothy A; Bernardo, Michael

    2016-06-01

    This is the first part of a two-part study in benchmarking the performance of fixed digital radiographic general X-ray systems. This paper concentrates on reporting findings related to quantitative analysis techniques used to establish comparative image quality metrics. A systematic technical comparison of the evaluated systems is presented in part two of this study. A novel quantitative image quality analysis method is presented with technical considerations addressed for peer review. The novel method was applied to seven general radiographic systems with four different makes of radiographic image receptor (12 image receptors in total). For the System Modulation Transfer Function (sMTF), the use of grid was found to reduce veiling glare and decrease roll-off. The major contributor in sMTF degradation was found to be focal spot blurring. For the System Normalised Noise Power Spectrum (sNNPS), it was found that all systems examined had similar sNNPS responses. A mathematical model is presented to explain how the use of stationary grid may cause a difference between horizontal and vertical sNNPS responses.

  11. Derivation and Cross-Validation of Cutoff Scores for Patients With Schizophrenia Spectrum Disorders on WAIS-IV Digit Span-Based Performance Validity Measures.

    Science.gov (United States)

    Glassmire, David M; Toofanian Ross, Parnian; Kinney, Dominique I; Nitch, Stephen R

    2016-06-01

    Two studies were conducted to identify and cross-validate cutoff scores on the Wechsler Adult Intelligence Scale-Fourth Edition Digit Span-based embedded performance validity (PV) measures for individuals with schizophrenia spectrum disorders. In Study 1, normative scores were identified on Digit Span-embedded PV measures among a sample of patients (n = 84) with schizophrenia spectrum diagnoses who had no known incentive to perform poorly and who put forth valid effort on external PV tests. Previously identified cutoff scores resulted in unacceptable false positive rates and lower cutoff scores were adopted to maintain specificity levels ≥90%. In Study 2, the revised cutoff scores were cross-validated within a sample of schizophrenia spectrum patients (n = 96) committed as incompetent to stand trial. Performance on Digit Span PV measures was significantly related to Full Scale IQ in both studies, indicating the need to consider the intellectual functioning of examinees with psychotic spectrum disorders when interpreting scores on Digit Span PV measures. © The Author(s) 2015.

  12. Design and application of a structured phantom for detection performance comparison between breast tomosynthesis and digital mammography

    Science.gov (United States)

    Cockmartin, L.; Marshall, N. W.; Zhang, G.; Lemmens, K.; Shaheen, E.; Van Ongeval, C.; Fredenberg, E.; Dance, D. R.; Salvagnini, E.; Michielsen, K.; Bosmans, H.

    2017-02-01

    This paper introduces and applies a structured phantom with inserted target objects for the comparison of detection performance of digital breast tomosynthesis (DBT) against 2D full field digital mammography (FFDM). The phantom consists of a 48 mm thick breast-shaped polymethyl methacrylate (PMMA) container filled with water and PMMA spheres of different diameters. Three-dimensionally (3D) printed spiculated masses (diameter range: 3.8-9.7 mm) and non-spiculated masses (1.6-6.2 mm) along with microcalcifications (90-250 µm) were inserted as targets. Reproducibility of the phantom application was studied on a single system using 30 acquisitions. Next, the phantom was evaluated on five different combined FFDM & DBT systems and target detection was compared for FFDM and DBT modes. Ten phantom images in both FFDM and DBT modes were acquired on these 5 systems using automatic exposure control. Five readers evaluated target detectability. Images were read with the four-alternative forced-choice (4-AFC) paradigm, with always one segment including a target and 3 normal background segments. The percentage of correct responses (PC) was assessed based on 10 trials of each reader for each object type, size and imaging modality. Additionally, detection threshold diameters at 62.5 PC were assessed via non-linear regression fitting of the psychometric curve. The reproducibility study showed no significant differences in PC values. Evaluation of target detection in FFDM showed that microcalcification detection thresholds ranged between 110 and 118 µm and were similar compared to the detection in DBT (range of 106-158 µm). In DBT, detection of both mass types increased significantly (p  =  0.0001 and p  =  0.0002 for non-spiculated and spiculated masses respectively) compared to FFDM, achieving almost 100% detection for all spiculated mass diameters. In conclusion, a structured phantom with inserted targets was able to show evidence for detectability

  13. The Effects of Degraded Digital Instrumentation and Control Systems on Human-system Interfaces and Operator Performance: HFE Review Guidance and Technical Basis

    Energy Technology Data Exchange (ETDEWEB)

    O' Hara, J.M.; W. Gunther, G. Martinez-Guridi

    2010-02-26

    New and advanced reactors will use integrated digital instrumentation and control (I&C) systems to support operators in their monitoring and control functions. Even though digital systems are typically highly reliable, their potential for degradation or failure could significantly affect operator performance and, consequently, impact plant safety. The U.S. Nuclear Regulatory Commission (NRC) supported this research project to investigate the effects of degraded I&C systems on human performance and plant operations. The objective was to develop human factors engineering (HFE) review guidance addressing the detection and management of degraded digital I&C conditions by plant operators. We reviewed pertinent standards and guidelines, empirical studies, and plant operating experience. In addition, we conducted an evaluation of the potential effects of selected failure modes of the digital feedwater system on human-system interfaces (HSIs) and operator performance. The results indicated that I&C degradations are prevalent in plants employing digital systems and the overall effects on plant behavior can be significant, such as causing a reactor trip or causing equipment to operate unexpectedly. I&C degradations can impact the HSIs used by operators to monitor and control the plant. For example, sensor degradations can make displays difficult to interpret and can sometimes mislead operators by making it appear that a process disturbance has occurred. We used the information obtained as the technical basis upon which to develop HFE review guidance. The guidance addresses the treatment of degraded I&C conditions as part of the design process and the HSI features and functions that support operators to monitor I&C performance and manage I&C degradations when they occur. In addition, we identified topics for future research.

  14. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Science.gov (United States)

    Leem, Hyun Tae; Choi, Yong; Kim, Kyu Bom; Lee, Sangwon; Yamamoto, Seiichi; Yeom, Jung-Yeol

    2017-02-01

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO4 reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm2 and the size of each LGSO scintillator element was 0.7×0.7×6 mm3. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400-600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  15. Quantitative performance of advanced resolution recovery strategies on SPECT images: evaluation with use of digital phantom models.

    Science.gov (United States)

    Onishi, Hideo; Motomura, Nobutoku; Fujino, Koichi; Natsume, Takahiro; Haramoto, Yasuhiro

    2013-01-01

    Several resolution recovery (RR) methods have been developed. This study was aimed to validate the following performance of the advanced RR methods: Evolution, Astonish, Flash3D, and 3D-OSEM. We compared the advanced RR method with filtered back projection (FBP) and standard order-subset expectation maximization (OSEM) using resolution (RES), cylinder/sphere (CYS), and myocardial (MYD) digital phantoms. The RES phantom was placed in three spheres. Sixteen spheres (hot and cold) were then placed in a concentric configuration (diameter: 96-9.6 mm) inside the CYS phantom. The MYD phantom was created by computer simulation with the use of an electron γ-shower 4 (EGS4) and it included two left ventricular defects in the myocardium. The performance was evaluated at source-to-detector distances (R-distance) of 166, 200, and 250 mm with reconstruction parameters (product of subset and iteration: SI) with use of the resolution recovery factor, count recovery, normalized mean square error (NMSE), and %CV. According to increased SI updates, the value of the FWHM decreased, and the effect was more obvious as the R-distance increased. The spatial resolution of the advanced RR method was 20 % better than that of FBP and OSEM. The resolution recovery ratio was 80 %, and the count recovery was maintained only in objects with a diameter of >30 mm in the advanced RR method. The NMSE and %CV was 50 and 30 % improved over FBP and OSEM, respectively. The advanced RR method caused overestimation due to Gibbs's phenomenon in the marginal region when the diameter of the sphere was 16-28.8 mm.

  16. Detector or system? Extending the concept of detective quantum efficiency to characterize the performance of digital radiographic imaging systems.

    Science.gov (United States)

    Samei, Ehsan; Ranger, Nicole T; MacKenzie, Alistair; Honey, Ian D; Dobbins, James T; Ravin, Carl E

    2008-12-01

    To develop an experimental method for measuring the effective detective quantum efficiency (eDQE) of digital radiographic imaging systems and evaluate its use in select imaging systems. A geometric phantom emulating the attenuation and scatter properties of the adult human thorax was employed to assess eight imaging systems in a total of nine configurations. The noise power spectrum (NPS) was derived from images of the phantom acquired at three exposure levels spanning the operating range of the system. The modulation transfer function (MTF) was measured by using an edge device positioned at the anterior surface of the phantom. Scatter measurements were made by using a beam-stop technique. All measurements, including those of phantom attenuation and estimates of x-ray flux, were used to compute the eDQE. The MTF results showed notable degradation owing to focal spot blur. Scatter fractions ranged between 11% and 56%, depending on the system. The eDQE(0) results ranged from 1%-17%, indicating a reduction of up to one order of magnitude and different rank ordering and performance among systems, compared with that implied in reported conventional detective quantum efficiency results from the same systems. The eDQE method was easy to implement, yielded reproducible results, and provided a meaningful reflection of system performance by quantifying image quality in a clinically relevant context. The difference in the magnitude of the measured eDQE and the ideal eDQE of 100% provides a great opportunity for improving the image quality of radiographic and mammographic systems while reducing patient dose. RSNA, 2008

  17. Digital Living at Home

    DEFF Research Database (Denmark)

    Andersen, Pernille Viktoria Kathja; Christiansen, Ellen Tove

    2013-01-01

    Does living with digital technology inevitably lead to digital living? Users talking about a digital home control system, they have had in their homes for eight years, indicate that there is more to living with digital technology than a functional-operational grip on regulation. Our analysis...... of these user voices has directed us towards a ‘home-keeping’ design discourse, which opens new horizons for design of digital home control systems by allowing users to perform as self-determined controllers and groomers of their habitat. The paper concludes by outlining the implications of a ‘home...

  18. Performance of computer-aided detection applied to full-field digital mammography in detection of breast cancers

    Energy Technology Data Exchange (ETDEWEB)

    Sadaf, Arifa, E-mail: arifa.sadaf@gmail.com [Department of Medical Imaging, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5 (Canada); Crystal, Pavel, E-mail: pavel.crystal@utoronto.ca [Department of Medical Imaging, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5 (Canada); Scaranelo, Anabel, E-mail: anabel.scaranelo@uhn.on.ca [Department of Medical Imaging, Princess Margaret Hospital, 610 University Avenue, Rm 3-922, Toronto, Ontario, M5G 2M9 (Canada); Helbich, Thomas, E-mail: thomas.helbich@meduniwien.ac.at [Medical University Vienna - General Hospital Vienna, Waehringer Guertel 18-20, Floor 7F, 1090 Vienna (Austria)

    2011-03-15

    Objective: The aim of this retrospective study was to evaluate performance of computer-aided detection (CAD) with full-field digital mammography (FFDM) in detection of breast cancers. Materials and Methods: CAD was retrospectively applied to standard mammographic views of 127 cases with biopsy proven breast cancers detected with FFDM (Senographe 2000, GE Medical Systems). CAD sensitivity was assessed in total group of 127 cases and for subgroups based on breast density, mammographic lesion type, mammographic lesion size, histopathology and mode of presentation. Results: Overall CAD sensitivity was 91% (115 of 127 cases). There were no statistical differences (p > 0.1) in CAD detection of cancers in dense breasts 90% (53/59) versus non-dense breasts 91% (62/68). There was statistical difference (p < 0.05) in CAD detection of cancers that appeared mammographically as microcalcifications only versus other mammographic manifestations. CAD detected 100% (44/44) of cancers manifesting as microcalcifications, 89% (47/53) as no-calcified masses or asymmetries, 88% (14/16) as masses with associated calcifications, and 71% (10/14) as architectural distortions. CAD sensitivity for cancers 1-10 mm was 84% (38/45); 11-20 mm 93% (55/59); and >20 mm 97% (22/23). Conclusion: CAD applied to FFDM showed 100% sensitivity in identifying cancers manifesting as microcalcifications only and high sensitivity 86% (71/83) for other mammographic appearances of cancer. Sensitivity is influenced by lesion size. CAD in FFDM is an adjunct helping radiologist in early detection of breast cancers.

  19. Performance of the Digital Science Partnership Remotely-Operated 0.5-Meter Corrected Dall-Kirkham Telescopes

    Science.gov (United States)

    Kielkopf, John F.; Carter, B.; Brown, C.; Hart, R.; Hay, J.; Waite, I.

    2007-12-01

    The Digital Science Partnership, a collaboration of the University of Louisville and the University of Southern Queensland, operates a pair of 0.5-meter telescopes for teaching, research, and informal education. The instruments were installed at sites near Toowoomba, Australia, and Louisville, Kentucky in 2006. The Planewave Instruments optical systems employ a unique Dall-Kirkham design incorporating a two-element corrector that demagnifies the image, flattens the focal plane, and reduces coma. These instruments have a moderately fast f/6.8 focal ratio and maintain image quality with little vignetting over a field 42 mm in diameter (0.7 degree). With a 9-micron pixel CCD such as the KAF-6303E, the image scale of 0.55 seconds of arc per pixel typically yields seeing-limited image quality at our sites. The telescopes and their enclosure are operated in a live remote observing mode through Linux-based software, including a dome-control system that uses RFID tags for absolute rotation encoding. After several months of testing and development we have examples of images and photometry from both sites that illustrate the performance of the system. We will discuss image quality, as well as practical matters such as pointing accuracy and field acquisition, auto-guiding, communication latency in large file transfer, and our experience with remote observing assisted by teleconferencing. Time-delay-integration (TDI) imaging, in which the telescope is stationary while the CCD is clocked to track in right ascension, is under study. The technique offers wide fields of view with very high signal-to-noise ratio, and can be implemented in robotically operated instruments used in monitoring, rapid-response, and educational programs. Results for conventional and TDI imaging from the dark site in Australia compared to the brighter suburban site in Kentucky show the benefits of access to dark sites through international partnerships that remote operation technology offers.

  20. Effects of voice timbre and accompaniment on working memory as measured by sequential monosyllabic digit recall performance.

    Science.gov (United States)

    Silverman, Michael J; Schwartzberg, Edward T

    2014-01-01

    Information is often paired with music in an attempt to facilitate recall and enhance learning. However, there is a lack of basic research investigating how music carrying information might facilitate recall and subsequent learning. The purpose of the current study was to determine the effects of voice timbre and accompaniment on working memory as measured by recall performance on a sequential digit recall task. Specific research questions were as follows: (a) How might female and male voice timbres affect serial recall? (b) How might piano, guitar, and no accompaniment affect serial recall? (c) Do music majors have enhanced recall accuracy when compared to nonmusic majors? The recall of information paired with six different melodies was tested on 60 university students. Melodies were composed and recorded using female and male voices with three levels of accompaniment: guitar, piano, and no accompaniment. Participants had more accurate recall during the male voice and piano and no accompaniment conditions and least accurate recall during the female voice and guitar accompaniment conditions. As participants had most accurate recall during the male voice and with piano or no accompaniment, clinicians are encouraged to consider using no accompaniment or piano accompaniment when initially teaching social and academic information paired with music for later recall. When possible, vocal timbre (i.e., the potential benefit of male voicing) should also be considered. Implications for clinical practice, limitations of the study, and suggestions for future research are provided. © the American Music Therapy Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Performance comparison between ceramic Ce:GAGG and single crystal Ce:GAGG with digital-SiPM

    Science.gov (United States)

    Park, C.; Kim, C.; Kim, J.; Lee, Y.; Na, Y.; Lee, K.; Yeom, J. Y.

    2017-01-01

    The Gd3Al2Ga3O12 (Ce:GAGG) is a new inorganic scintillator known for its attractive properties such as high light yield, stopping power and relatively fast decay time. In this study, we fabricated a ceramic Ce:GAGG scintillator as a cost-effective alternative to single crystal Ce:GAGG and, for the first time, investigated their performances when coupled to the digital silicon photomultiplier (dSiPM)—a new type of photosensor designed for applications in medical imaging, high energy and astrophysics. Compared to 3 × 3 × 2 mm3 sized single crystal Ce:GAGG, the translucent ceramic Ce:GAGG, which has a much lower transmittance than the single crystal, was determined to give an output signal amplitude that is approximately 61% of single crystal Ce:GAGG. The energy resolution of the 511 keV annihilation peak of a 22Na source was measured to be 9.9 ± 0.2% and 13.0 ± 0.3% for the single and ceramic scintillators respectively. On the other hand, the coincidence resolving time (CRT) of ceramic Ce:GAGG was 307 ± 23 ps, better than the 465 ± 37 ps acquired with single crystals—probably attributed to its slightly faster decay time and higher proportion of the fast decay component. The ceramic Ce:GAGG may be a promising cost-effective candidate for applications that do not require thick scintillators such as x-ray detectors and charged particle detectors, and those that require time-of-flight capabilities.

  2. Evaluation of the technical performance of three different commercial digital breast tomosynthesis systems in the clinical environment.

    Science.gov (United States)

    Rodríguez-Ruiz, A; Castillo, M; Garayoa, J; Chevalier, M

    2016-06-01

    The aim of this work was to research and evaluate the performance of three different digital breast tomosynthesis (DBT) systems in the clinical environment (Siemens Mammomat Inspiration, Hologic Selenia Dimensions, and Fujifilm Amulet Innovality). The characterization included the study of the detector, the automatic exposure control, and the resolution of DBT projections and reconstructed planes. The modulation transfer function (MTF) of the DBT projections was measured with a 1mm thick steel edge, showing a strong anisotropy (30-40% lower MTF0.5 frequencies in the tube travel direction). The in-plane MTF0.5, measured with a 25μm tungsten wire, ranges from 1.3 to 1.8lp/mm in the tube-travel direction and between 2.4 and 3.7lp/mm in the chest wall-nipple. In the latter direction, the MTF peak shift is more emphasized for large angular range systems (2.0 versus 1.0lp/mm). In-depth resolution of the planes, via the full width at half maximum (FWHM) from the point spread function of a 25μm tungsten wire, is not only influenced by angular range and yields 1.3-4.6mm among systems. The artifact spread function from 1mm diameter tungsten beads depends mainly on angular range, yielding two tendencies whether large (FWHM is 4.5mm) or small (FWHM is 10mm) angular range is used. DBT delivers per scan a mean glandular dose between 1.4 and 2.7mGy for a 45mm thick polymethyl methacrylate (PMMA) block. In conclusion, we have identified and analysed specific metrics that can be used for quality assurance of DBT systems. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  3. Digital power and performance analysis of inkjet printed ring oscillators based on electrolyte-gated oxide electronics

    Science.gov (United States)

    Cadilha Marques, Gabriel; Garlapati, Suresh Kumar; Dehm, Simone; Dasgupta, Subho; Hahn, Horst; Tahoori, Mehdi; Aghassi-Hagmann, Jasmin

    2017-09-01

    Printed electronic components offer certain technological advantages over their silicon based counterparts, like mechanical flexibility, low process temperatures, maskless and additive manufacturing possibilities. However, to be compatible to the fields of smart sensors, Internet of Things, and wearables, it is essential that devices operate at small supply voltages. In printed electronics, mostly silicon dioxide or organic dielectrics with low dielectric constants have been used as gate isolators, which in turn have resulted in high power transistors operable only at tens of volts. Here, we present inkjet printed circuits which are able to operate at supply voltages as low as ≤2 V. Our transistor technology is based on lithographically patterned drive electrodes, the dimensions of which are carefully kept well within the printing resolutions; the oxide semiconductor, the electrolytic insulator and the top-gate electrodes have been inkjet printed. Our inverters show a gain of ˜4 and 2.3 ms propagation delay time at 1 V supply voltage. Subsequently built 3-stage ring oscillators start to oscillate at a supply voltage of only 0.6 V with a frequency of ˜255 Hz and can reach frequencies up to ˜350 Hz at 2 V supply voltage. Furthermore, we have introduced a systematic methodology for characterizing ring oscillators in the printed electronics domain, which has been largely missing. Benefiting from this procedure, we are now able to predict the switching capacitance and driver capability at each stage, as well as the power consumption of our inkjet printed ring oscillators. These achievements will be essential for analyzing the performance and power characteristics of future inkjet printed digital circuits.

  4. Performance analysis of digital cameras versus chromatic white light (CWL) sensors for the localization of latent fingerprints in crime scenes

    Science.gov (United States)

    Jankow, Mathias; Hildebrandt, Mario; Sturm, Jennifer; Kiltz, Stefan; Vielhauer, Claus

    2012-06-01

    In future applications of contactless acquisition techniques for latent fingerprints the automatic localization of potential fingerprint traces in crime scenes is required. Our goal is to study the application of a camera-based approach1 comparing with the performance of chromatic white light (CWL) techniques2 for the latent fingerprint localization in coarse and the resulting acquisition using detailed scans. Furthermore, we briefly evaluate the suitability of the camera-based acquisition for the detection of malicious fingerprint traces using an extended camera setup in comparison to Kiltz et al.3 Our experimental setup includes a Canon EOS 550D4 digital single-lens reflex (DSLR) camera and a FRT MicroProf2005 surface measurement device with CWL6002 sensor. We apply at least two fingerprints to each surface in our test set with 8 different either smooth, textured and structured surfaces to evaluate the detection performance of the two localization techniques using different pre-processing and feature extraction techniques. Printed fingerprint patterns as reproducible but potentially malicious traces3 are additionally acquired and analyzed on foil and compact discs. Our results indicate positive tendency towards a fast localization using the camera-based technique. All fingerprints that are located using the CWL sensor are found using the camera. However,the disadvantage of the camera-based technique is that the size of the region of interest for the detailed scan for each potential latent fingerprint is usually slightly larger compared to the CWL-based localization. Furthermore, this technique does not acquire 3D data and the resulting images are distorted due to the necessary angle between the camera and the surface. When applying the camera-based approach, it is required to optimize the feature extraction and classification. Furthermore, the required acquisition time for each potential fingerprint needs to be estimated to determine the time-savings of the

  5. Design of a digital beam attenuation system for computed tomography. Part II. Performance study and initial results

    Energy Technology Data Exchange (ETDEWEB)

    Szczykutowicz, Timothy P. [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Mistretta, Charles A. [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin-Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Drive, Madison, Wisconsin 53706 (United States)

    2013-02-15

    Purpose: The purpose of this work is to present a performance study of the digital beam attenuator (DBA) for implementing fluence field modulated CT (FFMCT) using a simulation framework developed to model the incorporation of the DBA into an existing CT system. Additionally, initial results will be presented using a prototype DBA and the realization of the prototype will be described. To our knowledge, this study represents the first experimental use of a device capable of modulating x-ray fluence as a function of fan angle using a CT geometry. Methods: To realize FFMCT, the authors propose to use a wedge design in which one wedge is held stationary and another wedge is moved over the stationary wedge. Due to the wedge shape, the composite thickness of the two wedges changes as a function of the amount of overlap between the wedges. This design allows for the wedges to modulate the photon fluence incident onto a patient. Using a simulation environment, the effect of changing the number of wedges has on dose, scatter, detector dynamic range, and noise uniformity is explored. Experimental results are presented using a prototype DBA having ten Fe wedges and a c-arm CT system geometry. The experimental DBA results are compared to non-DBA scans using scatter and detector dynamic range as metrics. Both flat field and bowtie filtered CT acquisitions were simulated for comparison with the DBA. Results: Numerical results suggest that substantial gains in noise uniformity and scatter-to-primary ratio (SPR) can be obtained using only seven wedges. After seven wedges, the decrease in noise ununiformity and SPR falls off at a lower rate. Simulations comparing CT acquisitions between flat field, bowtie enabled, and DBA CT acquisitions suggest DBA-FFMCT can reduce dose relative to flat field CT by Almost-Equal-To 3 times. A bowtie filter under the same imaging conditions was shown to only allow a dose reduction of 1.65 times. Experimentally, a 10 wedge DBA prototype result showed

  6. A multilevel analysis of Swedish and Norwegian students’ overall and digital reading performance with a focus on equity aspects of education

    Directory of Open Access Journals (Sweden)

    Maria A. Rasmusson

    2016-02-01

    Full Text Available Abstract Background Influence of external factors in general, and socioeconomic background factors in particular, on traditional reading performance has been extensively researched and debated. While traditional reading is well investigated in this respect, there is a lack of studies on equity aspects related to digital reading achievement, in spite of the fact that time spent on reading from digital devices such as computers, tablets, and smart phones without doubt is increasing all over the world. In the hope of contributing to an area that up until now to a great extent has been left unresearched, the present study aims at investigating to what degree external factors, such as cultural and economic capital, parental pressure, and school choice, are related to 15-year-old students’ achievement in digital reading and in overall reading on both the student level and the school level in Norway and Sweden. Methods To conduct the analysis, multilevel structural modeling techniques have been used on PISA data from the two countries. Results The results for the Norwegian as well as for the Swedish sample showed that overall reading achievement was related to cultural capital in both countries, as expected, and in line with previous research. An identified digital reading factor, representing the unique aspects of digital reading achievement when overall reading was controlled for, was less influenced by the external factors of cultural and economic capital, and by parental pressure and school type, compared to performance in overall reading. Interestingly, on the school level, it was found that the external factors, school choice, and parental pressure related to overall reading achievement differently in the Norwegian and Swedish samples. School choice influenced overall reading in the Swedish data but not in the Norwegian data, and the opposite pattern was found for parental pressure. Conclusion In conclusion, it is suggested that the results

  7. Digital Beamforming Synthetic Aperture Radar (DBSAR): Performance Analysis During the Eco-3D 2011 and Summer 2012 Flight Campaigns

    Science.gov (United States)

    Rincon, Rafael F.; Fatoyinbo, Temilola; Carter, Lynn; Ranson, K. Jon; Vega, Manuel; Osmanoglu, Batuhan; Lee, SeungKuk; Sun, Guoqing

    2014-01-01

    The Digital Beamforming Synthetic Aperture radar (DBSAR) is a state-of-the-art airborne radar developed at NASA/Goddard for the implementation, and testing of digital beamforming techniques applicable to Earth and planetary sciences. The DBSAR measurements have been employed to study: The estimation of vegetation biomass and structure - critical parameters in the study of the carbon cycle; The measurement of geological features - to explore its applicability to planetary science by measuring planetary analogue targets. The instrument flew two test campaigns over the East coast of the United States in 2011, and 2012. During the campaigns the instrument operated in full polarimetric mode collecting data from vegetation and topography features.

  8. Video signal processing system uses gated current mode switches to perform high speed multiplication and digital-to-analog conversion

    Science.gov (United States)

    Gilliland, M. G.; Rougelot, R. S.; Schumaker, R. A.

    1966-01-01

    Video signal processor uses special-purpose integrated circuits with nonsaturating current mode switching to accept texture and color information from a digital computer in a visual spaceflight simulator and to combine these, for display on color CRT with analog information concerning fading.

  9. Observer Performance in the Use of Digital and Optical Microscopy for the Interpretation of Tissue-Based Biomarkers

    Directory of Open Access Journals (Sweden)

    Marios A. Gavrielides

    2014-01-01

    Full Text Available Background. We conducted a validation study of digital pathology for the quantitative assessment of tissue-based biomarkers with immunohistochemistry. Objective.\tTo examine observer agreement as a function of viewing modality (digital versus optical microscopy, whole slide versus tissue microarray (TMA review, biomarker type (HER2 incorporating membranous staining and Ki-67 with nuclear staining, and data type (continuous and categorical. Methods.\tEight pathologists reviewed 50 breast cancer whole slides (25 stained with HER2 and 25 with Ki-67 and 2 TMAs (1 stained with HER2, 1 with Ki-67, each containing 97 cores, using digital and optical microscopy. Results. Results showed relatively high overall interobserver and intermodality agreement, with different patterns specific to biomarker type. For HER2, there was better interobserver agreement for optical compared to digital microscopy for whole slides as well as better interobserver and intermodality agreement for TMAs. For Ki-67, those patterns were not observed. Conclusions. The differences in agreement patterns when examining different biomarkers and different scoring methods and reviewing whole slides compared to TMA stress the need for validation studies focused on specific pathology tasks to eliminate sources of variability that might dilute findings. The statistical uncertainty observed in our analyses calls for adequate sampling for each individual task rather than pooling cases.

  10. Performance analysis of gamma ray spectrometric parameters on digital signal and analog signal processing based MCA systems using NaI(Tl) detector

    Energy Technology Data Exchange (ETDEWEB)

    Kukreti, B.M., E-mail: bharatkuk@gmail.com [Atomic Minerals Directorate for Exploration and Research, Physics Laboratory, Department of Atomic Energy, Nongmynsong, AMD Complex, Shillong, Meghalaya 793019 (India); Sharma, G.K. [Atomic Minerals Directorate for Exploration and Research, Physics Laboratory, Department of Atomic Energy, Nongmynsong, AMD Complex, Shillong, Meghalaya 793019 (India)

    2012-05-15

    Accurate and speedy estimations of ppm range uranium and thorium in the geological and rock samples are most useful towards ongoing uranium investigations and identification of favorable radioactive zones in the exploration field areas. In this study with the existing 5 in. Multiplication-Sign 4 in. NaI(Tl) detector setup, prevailing background and time constraints, an enhanced geometrical setup has been worked out to improve the minimum detection limits for primordial radioelements K{sup 40}, U{sup 238} and Th{sup 232}. This geometrical setup has been integrated with the newly introduced, digital signal processing based MCA system for the routine spectrometric analysis of low concentration rock samples. Stability performance, during the long counting hours, for digital signal processing MCA system and its predecessor NIM bin based MCA system has been monitored, using the concept of statistical process control. Monitored results, over a time span of few months, have been quantified in terms of spectrometer's parameters such as Compton striping constants and Channel sensitivities, used for evaluating primordial radio element concentrations (K{sup 40}, U{sup 238} and Th{sup 232}) in geological samples. Results indicate stable dMCA performance, with a tendency of higher relative variance, about mean, particularly for Compton stripping constants. - Highlights: Black-Right-Pointing-Pointer Geometrical enhancement for ppm range primordial radio elemental determination. Black-Right-Pointing-Pointer Experimental constraints include detector setup, background and counting time. Black-Right-Pointing-Pointer Gamma spectrometric performance monitored on digital and analog MCA systems. Black-Right-Pointing-Pointer Study indicates higher variance of Compton stripping constants on digital MCA system.

  11. Characterization of semiconductor-laser phase noise and estimation of bit-error rate performance with low-speed offline digital coherent receivers.

    Science.gov (United States)

    Kikuchi, Kazuro

    2012-02-27

    We develop a systematic method for characterizing semiconductor-laser phase noise, using a low-speed offline digital coherent receiver. The field spectrum, the FM-noise spectrum, and the phase-error variance measured with such a receiver can completely describe phase-noise characteristics of lasers under test. The sampling rate of the digital coherent receiver should be much higher than the phase-fluctuation speed. However, 1 GS/s is large enough for most of the single-mode semiconductor lasers. In addition to such phase-noise characterization, interpolating the taken data at 1.25 GS/s to form a data stream at 10 GS/s, we can predict the bit-error rate (BER) performance of multi-level modulated optical signals at 10 Gsymbol/s. The BER degradation due to the phase noise is well explained by the result of the phase-noise measurements.

  12. Replacing single-view mediolateral oblique (MLO) digital mammography (DM) with synthesized mammography (SM) with digital breast tomosynthesis (DBT) images: Comparison of the diagnostic performance and radiation dose with two-view DM with or without MLO-DBT.

    Science.gov (United States)

    Kang, Hyo-Jin; Chang, Jung Min; Lee, Joongyub; Song, Sung Eun; Shin, Sung Ui; Kim, Won Hwa; Bae, Min Sun; Moon, Woo Kyung

    2016-11-01

    To evaluate the diagnostic performance and radiation dose of single view cranio-caudal (CC) digital mammography (DM) plus mediolateral oblique (MLO) digital breast tomosynthesis (DBT) combined with synthesized mammography (SM) in comparison with two-view DM with or without DBT. This study was approved by our institutional review board, and informed consent was obtained from 130 women. Paired two-view DM and single MLO-DBT with SM images were acquired, and four independent retrospective reading sessions of different combinations of DM, SM and DBT were performed for the presence of malignant tumors using jackknife alternative free-response receiver operator curve (JAFROC) methods. The diagnostic performances and average glandular dose (AGD) were compared between different combinations of DM, SM and DBT. Of 159 lesions in 130 patients, 27 were malignant. When using MLO-DBT with SM instead of MLO-DM, a significantly higher sensitivity (P=0.016) and specificity (P=0.012) were noted than with two-view DM, and comparable figure of merit (FOM), sensitivity, and specificity to two-view DM with DBT were noted. The mean AGD of CC-DM plus MLO-DBT with SM was 5.78mGy±1.06 per patient, which was significantly lower than that with two-view DM with MLO-DBT (8.45mGy±1.32; P <0.001) and slightly higher than that with two-view DM (5.30mGy±0.63). The combined use of CC-DM plus MLO-DBT with SM showed higher sensitivity and specificity to two-view DM with a smaller AGD increment and comparable diagnostic performance to that of two-view DM with MLO-DBT with a significantly lower mean AGD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Performance analysis of different surface reconstruction algorithms for 3D reconstruction of outdoor objects from their digital images.

    Science.gov (United States)

    Maiti, Abhik; Chakravarty, Debashish

    2016-01-01

    3D reconstruction of geo-objects from their digital images is a time-efficient and convenient way of studying the structural features of the object being modelled. This paper presents a 3D reconstruction methodology which can be used to generate photo-realistic 3D watertight surface of different irregular shaped objects, from digital image sequences of the objects. The 3D reconstruction approach described here is robust, simplistic and can be readily used in reconstructing watertight 3D surface of any object from its digital image sequence. Here, digital images of different objects are used to build sparse, followed by dense 3D point clouds of the objects. These image-obtained point clouds are then used for generation of photo-realistic 3D surfaces, using different surface reconstruction algorithms such as Poisson reconstruction and Ball-pivoting algorithm. Different control parameters of these algorithms are identified, which affect the quality and computation time of the reconstructed 3D surface. The effects of these control parameters in generation of 3D surface from point clouds of different density are studied. It is shown that the reconstructed surface quality of Poisson reconstruction depends on Samples per node (SN) significantly, greater SN values resulting in better quality surfaces. Also, the quality of the 3D surface generated using Ball-Pivoting algorithm is found to be highly depend upon Clustering radius and Angle threshold values. The results obtained from this study give the readers of the article a valuable insight into the effects of different control parameters on determining the reconstructed surface quality.

  14. Digital Preservation.

    Science.gov (United States)

    Yakel, Elizabeth

    2001-01-01

    Reviews research on digital preservation issues, including born-digital and digitally recreated documents. Discusses electronic records research; metadata and other standards; electronic mail; Web-based documents; moving images media; selection of materials for digitization, including primary sources; administrative issues; media stability…

  15. Digitization Best Practices

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Fei [Los Alamos National Laboratory; Holtkamp, Irma S. [Los Alamos National Laboratory; Knudson, Frances L. [Los Alamos National Laboratory

    2012-07-31

    This project involved performing tests and documenting results to determine best practices for digitizing older print documents. The digitization process is complicated, especially when original documents exhibit non-standard fonts and are faded. Tests focused on solutions to improve high quality scanning, increase OCR accuracy, and efficiently use embedded metadata. Results are summarized. From the test results on the right sides, we know that when we plan to digitize documents, we should balance Quantity and Quality based on our expectation, and then make final decision for the digitization process.

  16. Digitization Best Practices

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Fei [Los Alamos National Laboratory; Holtkamp, Irma S. [Los Alamos National Laboratory; Knudson, Frances L. [Los Alamos National Laboratory

    2012-07-31

    This project involved performing tests and documenting results to determine best practices for digitizing older print documents. The digitization process is complicated, especially when original documents exhibit non-standard fonts and are faded. Tests focused on solutions to improve high quality scanning, increase OCR accuracy, and efficiently use embedded metadata. Results are summarized. From the test results on the right sides, we know that when we plan to digitize documents, we should balance Quantity and Quality based on our expectation, and then make final decision for the digitization process.

  17. Digital automatic gain control

    Science.gov (United States)

    Uzdy, Z.

    1980-01-01

    Performance analysis, used to evaluated fitness of several circuits to digital automatic gain control (AGC), indicates that digital integrator employing coherent amplitude detector (CAD) is best device suited for application. Circuit reduces gain error to half that of conventional analog AGC while making it possible to automatically modify response of receiver to match incoming signal conditions.

  18. The research and discussion of digital library on cloud storage performance%数字图书馆的云存储性能研究与研讨

    Institute of Scientific and Technical Information of China (English)

    陈茫

    2014-01-01

    This paper discusses the application of digital libraries in the storage area of the cloud environment. Firstly, we introduce an open source, free, digital library architecture viable cloud storage environments; Secondly, we describe the key cloud storage replication technology, and build a digital library of realistic cloud storage architecture; finally, we detailed test and analyze the performance differences between different cloud storage.%首先,介绍一个开源的、免费的、可行的云环境下的数字图书馆存储构架;接下来,对云存储的关键复制技术逐一叙述,并构建数字图书馆的现实中云存储构架;最后,详细的测试和分析不同云存储之间的性能差异,探讨了数字图书馆在云环境下的存储领域的应用。

  19. O contributo das técnicas de marketing digital para a performance das organizações

    OpenAIRE

    Caetano, Diogo Vaz

    2014-01-01

    Dissertação de mestrado em Marketing, apresentado à Faculdade de Economia da Universidade de Coimbra, sob a orientação de Arnaldo Fernandes Matos Coelho. O marketing digital tem a sua génese na Internet e nas tecnologias de informação e comunicação. Atualmente verifica-se que a Internet ocupa um lugar privilegiado na vida dos consumidores, influenciando todos os aspectos do seu quotidiano. Tal oferece um conjunto de oportunidades que as organizações preparadas podem aproveitar, através de ...

  20. Performance of global look-up table strategy in digital image correlation with cubic B-spline interpolation and bicubic interpolation

    OpenAIRE

    Zhiwei Pan; Wei Chen; Zhenyu Jiang; Liqun Tang; Yiping Liu; Zejia Liu

    2016-01-01

    Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation (DIC) algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss–Newton (IC-GN) algorithm. The performance of this strategy, including accuracy, precision, and computation effi...

  1. Diagnostic performance in differentiation of breast lesion on digital mammograms: comparison among hard-copy film, 3-megapixel LCD monitor, and 5-megapixel LCD monitor.

    Science.gov (United States)

    Kamitani, Takeshi; Yabuuchi, Hidetake; Matsuo, Yoshio; Setoguchi, Taro; Sakai, Shuji; Okafuji, Takashi; Sunami, Shunya; Hatakenaka, Masamitsu; Ishii, Nobuhide; Kubo, Makoto; Tokunaga, Eriko; Yamamoto, Hidetaka; Honda, Hiroshi

    2011-01-01

    We compared observer performance of digital mammography among hard-copy readings and soft-copy readings using 3-megapixel (3M) and 5-megapixel (5M) liquid crystal display (LCD) monitors. Five experienced radiologists assessed 80 mammograms of 40 cancers and 40 benign lesions. There were no significant differences among the average A(z) of three modalities and among the κ values for intra- and interobserver agreement. The soft-copy reading using the 3M LCD monitor took a slightly longer time, although there were no significant differences.

  2. Performance evaluation of a radial in-plane digital speckle pattern interferometer using a diffractive optical element for residual stress measurement

    Science.gov (United States)

    Albertazzi, A., Jr.; Viotti, M. R.; Kapp, W. A.

    2010-08-01

    A digital speckle pattern (DSP) interferometer using a special diffractive optical element (DOE) was developed by the authors. A collimated laser beam is diffracted by the DOE in such a way that the first diffraction orders produce a circular double illuminated measurement area. Due to natural symmetry of the illumination scheme, the interferometer reaches pure radial in-plane sensitivity. It is demonstrated and verified that the resulting interferometer is not sensitive to laser wavelength variations at all. Its configuration is presented as well as its performance evaluation for residual stress measurements using the blind hole-drilling method.

  3. Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

    Science.gov (United States)

    Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2012-04-01

    In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

  4. Digital Culture and Digital Library

    Directory of Open Access Journals (Sweden)

    Yalçın Yalçınkaya

    2016-12-01

    Full Text Available In this study; digital culture and digital library which have a vital connection with each other are examined together. The content of the research consists of the interaction of culture, information, digital culture, intellectual technologies, and digital library concepts. The study is an entry work to integrity of digital culture and digital library theories and aims to expand the symmetry. The purpose of the study is to emphasize the relation between the digital culture and digital library theories acting intersection of the subjects that are examined. Also the perspective of the study is based on examining the literature and analytical evaluation in both studies (digital culture and digital library. Within this context, the methodology of the study is essentially descriptive and has an attribute for the transmission and synthesis of distributed findings produced in the field of the research. According to the findings of the study results, digital culture is an inclusive term that describes the effects of intellectual technologies in the field of information and communication. Information becomes energy and the spectrum of the information is expanding in the vertical rise through the digital culture. In this context, the digital library appears as a new living space of a new environment. In essence, the digital library is information-oriented; has intellectual technology support and digital platform; is in a digital format; combines information resources and tools in relationship/communication/cooperation by connectedness, and also it is the dynamic face of the digital culture in time and space independence. Resolved with the study is that the digital libraries are active and effective in the formation of global knowing and/or mass wisdom in the process of digital culture.

  5. Introduction to digital communication systems

    CERN Document Server

    Wesolowski, Krzysztof

    2009-01-01

    Combining theoretical knowledge and practical applications, this advanced-level textbook covers the most important aspects of contemporary digital communication systems. Introduction to Digital Communication Systems focuses on the rules of functioning digital communication system blocks, starting with the performance limits set by the information theory. Drawing on information relating to turbo codes and LDPC codes, the text presents the basic methods of error correction and detection, followed by baseband transmission methods, and single- and multi-carrier digital modulations. The basi

  6. On the comparison of analog and digital SiPM readout in terms of expected timing performance

    Energy Technology Data Exchange (ETDEWEB)

    Gundacker, S., E-mail: stefan.gundacker@cern.ch; Auffray, E.; Jarron, P.; Meyer, T.; Lecoq, P.

    2015-07-01

    In time of flight positron emission tomography (TOF-PET) and in particular for the EndoTOFPET-US Project (Frisch, 2013 [1]), and other applications for high energy physics, the multi-digital silicon photomultiplier (MD-SiPM) was recently proposed (Mandai and Charbon, 2012 [2]), in which the time of every single photoelectron is being recorded. If such a photodetector is coupled to a scintillator, the largest and most accurate timing information can be extracted from the cascade of the scintillation photons, and the most probable time of positron emission determined. The readout concept of the MD-SiPM is very different from that of the analog SiPM, where the individual photoelectrons are merely summed up and the output signal fed into the readout electronics. We have developed a comprehensive Monte Carlo (MC) simulation tool that describes the timing properties of the photodetector and electronics, the scintillation properties of the crystal and the light transfer within the crystal. In previous studies we have compared MC simulations with coincidence time resolution (CTR) measurements and found good agreement within less than 10% for crystals of different lengths (from 3 mm to 20 mm) coupled to SiPMs from Hamamatsu. In this work we will use the developed MC tool to directly compare the highest possible time resolution for both the analog and digital readout of SiPMs with different scintillator lengths. The presented studies reveal that the analog readout of SiPMs with microcell signal pile-up and leading edge discrimination can lead to nearly the same time resolution as compared to the maximum likelihood time estimation applied to MD-SiPMs. Consequently there is no real preference for either a digital or analog SiPM for the sake of achieving highest time resolution. However, the best CTR in the analog SiPM is observed for a rather small range of optimal threshold values, whereas the MD-SiPM provides stable CTR after roughly 20 registered photoelectron timestamps in

  7. SHDAS Production Digitizer Evaluation.

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, Bion J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    The Seismo-Hydroacoustic Data Acquisition System (SHDAS) is undergoing evaluation in preparation for its engineering, development, and deployment by the U.S Navy as an ocean bottom seismic monitoring system. At the current stage of development, the production digitizers are being evaluated to confirm their performance prior to packaging and assembly for deployment. The testing of the digitizers is being conducted at Delta Group Electronics, the digitizer fabricator, in San Diego, California, performed by Sandia National Laboratories with the assistance of Leidos and Delta Group Electronics.

  8. Digital photography

    National Research Council Canada - National Science Library

    Windsor, J S; Rodway, G W; Middleton, P M; McCarthy, S

    2006-01-01

    The emergence of a new generation of "point-and-shoot" digital cameras offers doctors a compact, portable and user-friendly solution to the recording of highly detailed digital photographs and video images...

  9. On the Performance of SVD-DWT Based Digital Video Watermarking Technique with Semi-Blind Detector

    Directory of Open Access Journals (Sweden)

    Tarzan Basaruddin

    2010-10-01

    Full Text Available This paper presents a watermarking technique for digital video. The proposed scheme is developed based on the work of Ganic and Chan which took the virtue of SVD and DWT. While the previous works of Chan has the blind detector property, our attempt is to develop a scheme with semi-blind detector, by using the merit of the DWT-SDV technique proposed by Ganic which was originally applied to still image. Overall, our experimental results show that our proposed scheme has a very good imperceptibility and is reasonably robust especially under several attacks such as compression, blurring, cropping, and sharpening.

  10. Digital Tectonics

    DEFF Research Database (Denmark)

    Christiansen, Karl; Borup, Ruben; Søndergaard, Asbjørn;

    2014-01-01

    Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated.......Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated....

  11. Digital squares

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Kim, Chul E

    1988-01-01

    Digital squares are defined and their geometric properties characterized. A linear time algorithm is presented that considers a convex digital region and determines whether or not it is a digital square. The algorithm also determines the range of the values of the parameter set of its preimages....... The analysis involves transforming the boundary of a digital region into parameter space of slope and y-intercept...

  12. Digital Citizenship

    Science.gov (United States)

    Isman, Aytekin; Canan Gungoren, Ozlem

    2014-01-01

    Era in which we live is known and referred as digital age.In this age technology is rapidly changed and developed. In light of these technological advances in 21st century, schools have the responsibility of training "digital citizen" as well as a good citizen. Digital citizens must have extensive skills, knowledge, Internet and …

  13. Digital Identifier Systems: Comparative Evaluation

    Directory of Open Access Journals (Sweden)

    Hamid Reza Khedmatgozar

    2015-02-01

    Full Text Available Identifier is one of the main elements in identifying an object in digital environment. Digital identifier systems were developed followed by a lot of problems such as violation of persistency and uniqueness of physical identifiers and URL in digital environment. These identifiers try to guarantee uniqueness and persistency of hostnames by using indirect names for Domain Name System (DNS. The main objective of this research is to identify qualified digital identifier system among other systems. To achieve the research objective, researchers have considered two major steps: first, identifying main criteria for distinguishing digital identifier based on literature review and focus group interview; and second, performing a comparative evaluation on common identifier systems in the world. Findings of first step demonstrated seven main criteria in three domains for distinguishing digital identifier systems: identifier uniqueness and persistency in the identifier features domain, digital identification, digital uniqueness, digital persistency and digital actionability in the digital coverage domain, and globality in the comprehensiveness of scope domain. In the second step, results of the comparative evaluation on common identifier systems indicated that six identifier systems, included, DOI, Handle, UCI, URN, ARK and PURL, are appropriate choices for using as a digital identifier system. Also, according to these results, three identification systems Including NBN, MARIAM and ISNI were identified as suitable choices for digital identification in certain specialized fields. According to many benefits of using these identifiers in important applied fields, such as, digital content chains and networks integration, digital right management, cross referencing, digital libraries and citation analysis, results of this study can help digital environment experts to diagnose digital identifier and their effective use in applied fields.

  14. WAIS-IV reliable digit span is no more accurate than age corrected scaled score as an indicator of invalid performance in a veteran sample undergoing evaluation for mTBI.

    Science.gov (United States)

    Spencer, Robert J; Axelrod, Bradley N; Drag, Lauren L; Waldron-Perrine, Brigid; Pangilinan, Percival H; Bieliauskas, Linas A

    2013-01-01

    Reliable Digit Span (RDS) is a measure of effort derived from the Digit Span subtest of the Wechsler intelligence scales. Some authors have suggested that the age-corrected scaled score provides a more accurate measure of effort than RDS. This study examined the relative diagnostic accuracy of the traditional RDS, an extended RDS including the new Sequencing task from the Wechsler Adult Intelligence Scale-IV, and the age-corrected scaled score, relative to performance validity as determined by the Test of Memory Malingering. Data were collected from 138 Veterans seen in a traumatic brain injury clinic. The traditional RDS (≤ 7), revised RDS (≤ 11), and Digit Span age-corrected scaled score ( ≤ 6) had respective sensitivities of 39%, 39%, and 33%, and respective specificities of 82%, 89%, and 91%. Of these indices, revised RDS and the Digit Span age-corrected scaled score provide the most accurate measure of performance validity among the three measures.

  15. Parallel digital forensics infrastructure.

    Energy Technology Data Exchange (ETDEWEB)

    Liebrock, Lorie M. (New Mexico Tech, Socorro, NM); Duggan, David Patrick

    2009-10-01

    This report documents the architecture and implementation of a Parallel Digital Forensics infrastructure. This infrastructure is necessary for supporting the design, implementation, and testing of new classes of parallel digital forensics tools. Digital Forensics has become extremely difficult with data sets of one terabyte and larger. The only way to overcome the processing time of these large sets is to identify and develop new parallel algorithms for performing the analysis. To support algorithm research, a flexible base infrastructure is required. A candidate architecture for this base infrastructure was designed, instantiated, and tested by this project, in collaboration with New Mexico Tech. Previous infrastructures were not designed and built specifically for the development and testing of parallel algorithms. With the size of forensics data sets only expected to increase significantly, this type of infrastructure support is necessary for continued research in parallel digital forensics. This report documents the implementation of the parallel digital forensics (PDF) infrastructure architecture and implementation.

  16. Digital preservation

    CERN Document Server

    Deegan, Marilyn

    2013-01-01

    Digital preservation is an issue of huge importance to the library and information profession right now. With the widescale adoption of the internet and the rise of the world wide web, the world has been overwhelmed by digital information. Digital data is being produced on a massive scale by individuals and institutions: some of it is born, lives and dies only in digital form, and it is the potential death of this data, with its impact on the preservation of culture, that is the concern of this book. So how can information professionals try to remedy this? Digital preservation is a complex iss

  17. Digital subtraktion

    DEFF Research Database (Denmark)

    Mussmann, Bo Redder

    2004-01-01

    Digital subtraktion er en metode til at fjerne uønskede oplysninger i et røntgenbillede. Subtraktionsteknikken bruges primært i forbindelse med angiografi hvor man kun er interesseret i at se selve karret. Derfor er digital subtraktion i daglig tale synonymt med DSA eller DVI – hhv. Digital...... Subtraction Angiography eller Digital Vascular Imaging. Benævnelserne er to røntgenfirmaers navn for den samme teknik. Digital subtraktion kræver speciel software, samt at apparaturet kan eksponere i serier....

  18. Digital Natives or Digital Tribes?

    Science.gov (United States)

    Watson, Ian Robert

    2013-01-01

    This research builds upon the discourse surrounding digital natives. A literature review into the digital native phenomena was undertaken and found that researchers are beginning to identify the digital native as not one cohesive group but of individuals influenced by other factors. Primary research by means of questionnaire survey of technologies…

  19. Multiscale variation-aware techniques for high-performance digital microfluidic lab-on-a-chip component placement.

    Science.gov (United States)

    Liao, Chen; Hu, Shiyan

    2011-03-01

    The invention of microfluidic lab-on-a-chip alleviates the burden of traditional biochemical laboratory procedures which are often very expensive. Device miniaturization and increasing design complexity have mandated a shift in digital microfluidic lab-on-a-chip design from traditional manual design to computer-aided design (CAD) methodologies. As an important procedure in the lab-on-a-chip layout CAD, the lab-on-a-chip component placement determines the physical location and the starting time of each operation such that the overall completion time is minimized while satisfying nonoverlapping constraint, resource constraint, and scheduling constraint. In this paper, a multiscale variation-aware optimization technique based on integer linear programming is proposed for the lab-on-a-chip component placement. The simulation results demonstrate that without considering variations, our technique always satisfies the design constraints and largely outperforms the state-of-the-art approach, with up to 65.9% reduction in completion time. When considering variations, the variation-unaware design has the average yield of 2%, while our variation-aware technique always satisfies the yield constraint with only 7.7% completion time increase.

  20. Hardware architecture of high-performance digital hologram generator on the basis of a pixel-by-pixel calculation scheme.

    Science.gov (United States)

    Seo, Young-Ho; Lee, Yoon-Hyuk; Yoo, Ji-Sang; Kim, Dong-Wook

    2012-06-20

    In this paper we propose a hardware architecture for high-speed computer-generated hologram generation that significantly reduces the number of memory access times to avoid the bottleneck in the memory access operation. For this, we use three main schemes. The first is pixel-by-pixel calculation, rather than light source-by-source calculation. The second is a parallel calculation scheme extracted by modifying the previous recursive calculation scheme. The last scheme is a fully pipelined calculation scheme and exactly structured timing scheduling, achieved by adjusting the hardware. The proposed hardware is structured to calculate a row of a computer-generated hologram in parallel and each hologram pixel in a row is calculated independently. It consists of and input interface, an initial parameter calculator, hologram pixel calculators, a line buffer, and a memory controller. The implemented hardware to calculate a row of a 1920×1080 computer-generated hologram in parallel uses 168,960 lookup tables, 153,944 registers, and 19,212 digital signal processing blocks in an Altera field programmable gate array environment. It can stably operate at 198 MHz. Because of three schemes, external memory bandwidth is reduced to approximately 1/20,000 of the previous ones at the same calculation speed.

  1. Improving the performance of digital soil maps by the application of remotely sensed data used in terroir mapping - case study of the Tokaj wine region

    Science.gov (United States)

    Takács, Katalin; Laborczi, Annamária; Lukácsy, György; Pásztor, László

    2015-04-01

    The aim of the soil mapping is to explore and visualize the spatial extension and variability of the thematic knowledge about soils. Soil maps are thematic maps, which can present information about the primary or derivative soil characteristics, soil classes and knowledge about the processes, function and services of the soils. The method for information obtaining about soils is sampling which results only point data and should be spatially extended by a properly chosen process. The digital soil mapping (DSM) method uses environmental auxiliary variables for the spatial extension. These variables should be in direct or indirect relation with the target soil characteristic and should provide full coverage for the target area. Environmental variables can be derived from digital elevation models, land cover data or satellite images which can be obtained most efficiently with remote sensing methods. The soil-landscape relation can be modelled by geostatistical and data mining methods based the soil data and auxiliary variables. The study area is Tokaj wine region (approximately 400 km2) which is located in Northeast-Hungary, in Tokaj Mountains. Soil data is available for 200 sampling points. The terrain variables - such as elevation, slope, aspect and other derivatives - are derived from a relatively high resolution digital elevation model (DEM; 1 m), that was generated by LiDAR. The other environmental variables - such as land cover, NDVI - are prepared based on Landsat images which are acquired at different seasons in line with vegetation phenology and soil coverage. The target maps are prepared by digital soil mapping methods. For the analysis of the relationship between soil sampling data and the auxiliary variables different geostatistical methods are used to choose the most appropriate environmental variables for the spatial modelling. The spatial extension of point data are performed by interpolation methods. For summarizing the main aim of this study is to test

  2. High-performance low-leakage regions of nano-scaled CMOS digital gates under variations of threshold voltage and mobility

    Institute of Scientific and Technical Information of China (English)

    Hossein AGHABABA; Behjat FOROUZANDEH; Ali AFZALI-KUSHA

    2012-01-01

    We propose a modeling methodology for both leakage power consumption and delay of basic CMOS digital gates in the presence of threshold voltage and mobility variations.The key parameters in determining the leakage and delay are OFF and ON currents,respectively,which are both affected by the variation of the threshold voltage.Additionally,the current is a strong function of mobility.The proposed methodology relies on a proper modeling of the threshold voltage and mobility variations,which may be induced by any source.Using this model,in the plane of threshold voltage and mobility,we determine regions for different combinations of performance (speed) and leakage.Based on these regions,we discuss the trade-offbetween leakage and delay where the leakage-delay-product is the optimization objective.To assess the accuracy of the proposed model,we compare its predictions with those of HSPICE simulations for both basic digital gates and ISCAS85 benchmark circuits in 45-,65-,and 90-nm technologies.

  3. Improved performance of analog and digital acousto-optic modulation with feedback under profiled beam propagation for secure communication using chaos

    Science.gov (United States)

    Almehmadi, Fares S.; Chatterjee, Monish R.

    2014-12-01

    Using intensity feedback, the closed-loop behavior of an acousto-optic hybrid device under profiled beam propagation has been recently shown to exhibit wider chaotic bands potentially leading to an increase in both the dynamic range and sensitivity to key parameters that characterize the encryption. In this work, a detailed examination is carried out vis-à-vis the robustness of the encryption/decryption process relative to parameter mismatch for both analog and pulse code modulation signals, and bit error rate (BER) curves are used to examine the impact of additive white noise. The simulations with profiled input beams are shown to produce a stronger encryption key (i.e., much lower parametric tolerance thresholds) relative to simulations with uniform plane wave input beams. In each case, it is shown that the tolerance for key parameters drops by factors ranging from 10 to 20 times below those for uniform plane wave propagation. Results are shown to be at consistently lower tolerances for secure transmission of analog and digital signals using parameter tolerance measures, as well as BER performance measures for digital signals. These results hold out the promise for considerably greater information transmission security for such a system.

  4. 基于成本收益法的高校图书馆数字资源绩效评估%Research on University Library ’s Digital Resources Performance Evaluation Based on Cost Benefit Method

    Institute of Scientific and Technical Information of China (English)

    浮肖肖

    2015-01-01

    This paper discusses university library’s digital resources performance evaluation based on cost benefit method from five aspects of the benefit index system, the cost index system, the determination of evaluation index weight, the quantization of digital resource digital resources of university library index, and the comparative analysis of digital resource’s cost and benefit.%从收益指标体系、成本指标体系、评价指标权重的确定、数字资源指标量化、数字资源成本与收益的比较分析5个方面,论述了基于成本收益法的高校图书馆数字资源绩效评估。

  5. Performance of global look-up table strategy in digital image correlation with cubic B-spline interpolation and bicubic interpolation

    Directory of Open Access Journals (Sweden)

    Zhiwei Pan

    2016-05-01

    Full Text Available Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation (DIC algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss–Newton (IC-GN algorithm. The performance of this strategy, including accuracy, precision, and computation efficiency, is evaluated through a theoretical and experimental study, using the one with widely employed bicubic interpolation as a benchmark. The global look-up table strategy with cubic B-spline interpolation improves significantly the accuracy of the IC-GN algorithm-based DIC method compared with the one using the bicubic interpolation, at a trivial price of computation efficiency.

  6. An Electronic Workshop on the Performance Seeking Control and Propulsion Controlled Aircraft Results of the F-15 Highly Integrated Digital Electronic Control Flight Research Program

    Science.gov (United States)

    Powers, Sheryll Goecke (Compiler)

    1995-01-01

    Flight research for the F-15 HIDEC (Highly Integrated Digital Electronic Control) program was completed at NASA Dryden Flight Research Center in the fall of 1993. The flight research conducted during the last two years of the HIDEC program included two principal experiments: (1) performance seeking control (PSC), an adaptive, real-time, on-board optimization of engine, inlet, and horizontal tail position on the F-15; and (2) propulsion controlled aircraft (PCA), an augmented flight control system developed for landings as well as up-and-away flight that used only engine thrust (flight controls locked) for flight control. In September 1994, the background details and results of the PSC and PCA experiments were presented in an electronic workshop, accessible through the Dryden World Wide Web (http://www.dfrc.nasa.gov/dryden.html) and as a compact disk.

  7. Digital Insights

    DEFF Research Database (Denmark)

    Knudsen, Gry Høngsmark

    , by incorporating media as both channel, frame, and apparatus for advertising response, the dissertation brings into attention that more aspects than the text-reader relationship influence ad response. Finally, the dissertation proposes the assemblage approach for exploring big data in consumer culture research......This dissertation forwards the theory of digital consumer-response as a perspective to examine how digital media practices influence consumers’ response to advertising. Digital consumer-response is a development of advertising theory that encompasses how consumers employ their knowledge...... and practices with digital media, when they meet and interpret advertising. Through studies of advertising response on YouTube and experiments with consumers’ response to digitally manipulated images, the dissertation shows how digital media practices facilitate polysemic and socially embedded advertising...

  8. Digital Forensics

    OpenAIRE

    Ψευτέλης, Αθανάσιος Δημήτρης

    2013-01-01

    A reprint from American Scientist the magazine of Sigma Xi, The Scientific Research Society Since the 1980s, computers have had increasing roles in all aspects of human life—including an involvement in criminal acts. This development has led to the rise of digital forensics, the uncovering and examination of evidence located on all things electronic with digital storage, including computers, cell phones, and networks. Digital forensics researchers and practitione...

  9. Digital printing

    Science.gov (United States)

    Sobotka, Werner K.

    1997-02-01

    Digital printing is described as a tool to replace conventional printing machines completely. Still this goal was not reached until now with any of the digital printing technologies to be described in the paper. Productivity and costs are still the main parameters and are not really solved until now. Quality in digital printing is no problem anymore. Definition of digital printing is to transfer digital datas directly on the paper surface. This step can be carried out directly or with the use of an intermediate image carrier. Keywords in digital printing are: computer- to-press; erasable image carrier; image carrier with memory. Digital printing is also the logical development of the new digital area as it is pointed out in Nicholas Negropotes book 'Being Digital' and also the answer to networking and Internet technologies. Creating images text and color in one country and publishing the datas in another country or continent is the main advantage. Printing on demand another big advantage and last but not least personalization the last big advantage. Costs and being able to coop with this new world of prepress technology is the biggest disadvantage. Therefore the very optimistic growth rates for the next few years are really nonexistent. The development of complete new markets is too slow and the replacing of old markets is too small.

  10. Digital displacements

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2014-01-01

    In recent years digital reforms are being introduced in the municipal landscape of Denmark. The reforms address the interaction between citizen and local authority. The aim is, that by 2015 at least 80 per cent of all correspondence between citizens and public authority will be transmitted through...... digital interface. However, the transformation of citizen services from traditional face-to-face interaction to digital self-service gives rise to new practices; some citizens need support to be able to manage self-service through digital tools. A mixture of support and teaching, named co...

  11. Aerodynamic performance of NACA four-digit profiles in small-scale wind turbines for small farms

    Directory of Open Access Journals (Sweden)

    Paulo Alexandre Costa Rocha

    2015-06-01

    Full Text Available In Brazil, there are many places that do not have access to electric energy, mainly in rural areas with small farms. This situation has accentuated the importance of renewable energy sources, such as wind energy. This work consisted of the design, construction and field testing of two small three-bladed wind turbines with two different aerodynamic profiles. The aim of the study was to compare the profile influence on the turbine aerodynamic performance. Using the blade element momentum (BEM theory, two wind turbines were designed and built with different cross-section aerodynamic profiles (NACA 0012 (symmetric and 4412 (chambered. Following statistical analysis, the results of the field tests demonstrated that the performances of the turbines are similar when the rotational speed is near the designed value (?=5. However, when the rotational speed is under or above the designed value, the NACA 4412 profile yields superior performance

  12. Forensic examination of ink by high-performance thin layer chromatography--the United States Secret Service Digital Ink Library.

    Science.gov (United States)

    Neumann, Cedric; Ramotowski, Robert; Genessay, Thibault

    2011-05-13

    Forensic examinations of ink have been performed since the beginning of the 20th century. Since the 1960s, the International Ink Library, maintained by the United States Secret Service, has supported those analyses. Until 2009, the search and identification of inks were essentially performed manually. This paper describes the results of a project designed to improve ink samples' analytical and search processes. The project focused on the development of improved standardization procedures to ensure the best possible reproducibility between analyses run on different HPTLC plates. The successful implementation of this new calibration method enabled the development of mathematical algorithms and of a software package to complement the existing ink library.

  13. Workflow Tools for Digital Curation

    Directory of Open Access Journals (Sweden)

    Andrew James Weidner

    2013-04-01

    Full Text Available Maintaining usable and sustainable digital collections requires a complex set of actions that address the many challenges at various stages of the digital object lifecycle. Digital curation activities enhance access and retrieval, maintain quality, add value, and facilitate use and re-use over time. Digital resource lifecycle management is becoming an increasingly important topic as digital curators actively explore software tools that perform metadata curation and file management tasks. Accordingly, the University of North Texas (UNT Libraries develop tools and workflows that streamline production and quality assurance activities. This article demonstrates two open source software tools, AutoHotkey and Selenium IDE, which the UNT Digital Libraries Division has adopted for use during the pre-ingest and post-ingest stages of the digital resource lifecycle.

  14. Digital Libraries

    CERN Document Server

    Papy, Fabrice

    2008-01-01

    Of vital interest to all librarians and information specialists, this book presents all aspects of the effects of digitization of today's and tomorrow's libraries. From social to technical issues, Digital Libraries includes chapters on the growth of the role of librarian, the reader experience, cataloging, search engines, OPAC, law, ergonomic studies, and the future of libraries.

  15. Digital Audiobooks:

    DEFF Research Database (Denmark)

    Have, Iben; Pedersen, Birgitte Stougaard

    Audiobooks are rapidly gaining popularity with widely accessible digital downloading and streaming services. The paper is framing how the digital audiobook expands and changes the target groups for book publications and how it as an everyday activity is creating new reading experiences, places...

  16. Architectural Optimization of Digital Libraries

    Science.gov (United States)

    Biser, Aileen O.

    1998-01-01

    This work investigates performance and scaling issues relevant to large scale distributed digital libraries. Presently, performance and scaling studies focus on specific implementations of production or prototype digital libraries. Although useful information is gained to aid these designers and other researchers with insights to performance and scaling issues, the broader issues relevant to very large scale distributed libraries are not addressed. Specifically, no current studies look at the extreme or worst case possibilities in digital library implementations. A survey of digital library research issues is presented. Scaling and performance issues are mentioned frequently in the digital library literature but are generally not the focus of much of the current research. In this thesis a model for a Generic Distributed Digital Library (GDDL) and nine cases of typical user activities are defined. This model is used to facilitate some basic analysis of scaling issues. Specifically, the calculation of Internet traffic generated for different configurations of the study parameters and an estimate of the future bandwidth needed for a large scale distributed digital library implementation. This analysis demonstrates the potential impact a future distributed digital library implementation would have on the Internet traffic load and raises questions concerning the architecture decisions being made for future distributed digital library designs.

  17. PET performance and MRI compatibility evaluation of a digital, ToF-capable PET/MRI insert equipped with clinical scintillators

    Science.gov (United States)

    Schug, David; Wehner, Jakob; Dueppenbecker, Peter Michael; Weissler, Bjoern; Gebhardt, Pierre; Goldschmidt, Benjamin; Salomon, Andre; Kiessling, Fabian; Schulz, Volkmar

    2015-09-01

    We evaluate the MR compatibility of the Hyperion-IID positron emission tomography (PET) insert, which allows simultaneous operation in a clinical magnetic resonance imaging (MRI) scanner. In contrast to previous investigations, this work aims at the evaluation of a clinical crystal configuration. An imaging-capable demonstrator with an axial field-of-view of 32 mm and a crystal-to-crystal spacing of 217.6 mm was equipped with LYSO scintillators with a pitch of 4 mm which were read out in a one-to-one coupling scheme by sensor tiles composed of digital silicon photomultipliers from Philips Digital Photon Counting (DPC 3200-22). The PET performance degradation (energy resolution and coincidence resolution time (CRT)) was evaluated during simultaneous operation of the MRI scanner. We used clinically motivated imaging sequences as well as synthetic gradient stress test sequences. Without activity of the MRI scanner, we measured for trigger scheme 1 (first photon trigger) an energy resolution of 11.4% and a CRT of 213 ps for a narrow energy (NE) window using five 22Na point-like sources. When applying the synthetic gradient sequences, we found worst-case relative degradations of the energy resolution by 5.1% and of the CRT by 33.9%. After identifying the origin of the degradations and implementing a fix to the read-out hardware, the same evaluation revealed no degradation of the PET performance anymore even when the most demanding gradient stress tests were applied. The PET performance of the insert was initially evaluated using the point sources, a high-activity phantom and hot-rod phantoms in order to assess the spatial resolution. Trigger schemes 2-4 delivered an energy resolution of 11.4% as well and CRTs of 279 ps, 333 ps and 557 ps for the NE window, respectively. An isocenter sensitivity of 0.41% using the NE window and 0.71% with a wide energy window was measured. Using a hot-rod phantom, a spatial resolution in the order of 2 mm was demonstrated and the

  18. Video gaming and gender differences in digital and printed reading performance among 15-year-olds students in 26 countries.

    Science.gov (United States)

    Borgonovi, Francesca

    2016-04-01

    Video games are a favorite leisure-time activity among teenagers worldwide. This study examines cross-national gender differences in reading achievement and video gaming and whether video gaming explains gender differences in reading achievement and differences in performance between paper-based and computer-based reading. We use data from a representative sample of 145,953 students from 26 countries who sat the PISA 2012 assessments and provided self-reports on use of video games. Although boys tend to have poorer results in both the computer-based and the paper-based reading assessments, boys' under achievement is smaller when the assessment is delivered on computer than when it is delivered on paper. Boys underperformance compared to girls in the two reading assessments is particularly pronounced among low-achieving students. Among both boys and girls moderate use of single-player games is associated with a performance advantage. However, frequent engagement with collaborative online games is generally associated with a steep reduction in achievement, particularly in the paper-based test and particularly among low-achieving students. Excessive gaming may hinder academic achievement, but moderate gaming can promote positive student outcomes. In many countries video gaming explains the difference in the gender gap in reading between the paper-based and the computer-based assessments.

  19. Digital chest radiography

    DEFF Research Database (Denmark)

    Debess, Jeanne Elisabeth; Vejle-Sørensen, Jens Kristian; Thomsen, Henrik;

    2015-01-01

    of clinical supervisors. Optimal collimation is determined by European and Regional Danish guidelines. The areal between current and optimal collimation is calculated. The experimental research is performed in September - October 2014 Siemens Axiom Aristos digital radiography system DR using 150 kV, 1,25 -3......Purpose: Quality improvement of basic radiography focusing on collimation and dose reduction in digital chest radiography Methods and Materials:A retrospective study of digital chest radiography is performed to evaluate the primary x-ray tube collimation of the PA and lateral radiographs. Data from...... one hundred fifty self-reliant female patients between 15 and 55 years of age are included in the study. The clinical research is performed between September and November 2014 where 3rd year Radiography students collect data on four Danish x-ray departments using identical procedures under guidance...

  20. Initial performance studies of a wearable brain positron emission tomography camera based on autonomous thin-film digital Geiger avalanche photodiode arrays.

    Science.gov (United States)

    Schmidtlein, Charles R; Turner, James N; Thompson, Michael O; Mandal, Krishna C; Häggström, Ida; Zhang, Jiahan; Humm, John L; Feiglin, David H; Krol, Andrzej

    2017-01-01

    Using analytical and Monte Carlo modeling, we explored performance of a lightweight wearable helmet-shaped brain positron emission tomography (PET), or BET camera, based on thin-film digital Geiger avalanche photodiode arrays with Lutetium-yttrium oxyorthosilicate (LYSO) or [Formula: see text] scintillators for imaging in vivo human brain function of freely moving and acting subjects. We investigated a spherical cap BET and cylindrical brain PET (CYL) geometries with 250-mm diameter. We also considered a clinical whole-body (WB) LYSO PET/CT scanner. The simulated energy resolutions were 10.8% (LYSO) and 3.3% ([Formula: see text]), and the coincidence window was set at 2 ns. The brain was simulated as a water sphere of uniform F-18 activity with a radius of 100 mm. We found that BET achieved [Formula: see text] better noise equivalent count (NEC) performance relative to the CYL and [Formula: see text] than WB. For 10-mm-thick [Formula: see text] equivalent mass systems, LYSO (7-mm thick) had [Formula: see text] higher NEC than [Formula: see text]. We found that [Formula: see text] scintillator crystals achieved [Formula: see text] full-width-half-maximum spatial resolution without parallax errors. Additionally, our simulations showed that LYSO generally outperformed [Formula: see text] for NEC unless the timing resolution for [Formula: see text] was considerably smaller than that presently used for LYSO, i.e., well below 300 ps.

  1. Dataset on the learning performance of ECDL digital skills of undergraduate students for comparing educational gaming, gamification and social networking

    Directory of Open Access Journals (Sweden)

    Luis de-Marcos

    2017-04-01

    Full Text Available This paper reports data about the learning performance of students using four different motivational tools: an educational game, a gamified plugin, a social networking website and a gamified social networking website. It also reports a control group. The data pertain to 379 students of an undergraduate course that covers basic Information and Communication Technology (ICT skills in Spain. Data corresponds to different learning modules of the European Computer Driving License (ECDL initiative. The data include variables of four pre-test scores, four post-test scores and a final examination. It was gathered using a quasi-experimental research design during 2014. Data reported here refers to the research paper in (de-Marcos et al., 2016 [1].

  2. Dataset on the learning performance of ECDL digital skills of undergraduate students for comparing educational gaming, gamification and social networking.

    Science.gov (United States)

    de-Marcos, Luis; García-López, Eva; García-Cabot, Antonio

    2017-04-01

    This paper reports data about the learning performance of students using four different motivational tools: an educational game, a gamified plugin, a social networking website and a gamified social networking website. It also reports a control group. The data pertain to 379 students of an undergraduate course that covers basic Information and Communication Technology (ICT) skills in Spain. Data corresponds to different learning modules of the European Computer Driving License (ECDL) initiative. The data include variables of four pre-test scores, four post-test scores and a final examination. It was gathered using a quasi-experimental research design during 2014. Data reported here refers to the research paper in (de-Marcos et al., 2016) [1].

  3. SENTINEL-2 Global Reference Image Validation and Application to Multitemporal Performances and High Latitude Digital Surface Model

    Science.gov (United States)

    Gaudel, A.; Languille, F.; Delvit, J. M.; Michel, J.; Cournet, M.; Poulain, V.; Youssefi, D.

    2017-05-01

    In the frame of the Copernicus program of the European Commission, Sentinel-2 is a constellation of 2 satellites with a revisit time of 5 days in order to have temporal images stacks and a global coverage over terrestrial surfaces. Satellite 2A was launched in June 2015, and satellite 2B will be launched in March 2017. In cooperation with the European Space Agency (ESA), the French space agency (CNES) is in charge of the image quality of the project, and so ensures the CAL/VAL commissioning phase during the months following the launch. This cooperation is also extended to routine phase as CNES supports European Space Research Institute (ESRIN) and the Sentinel-2 Mission performance Centre (MPC) for validation in geometric and radiometric image quality aspects, and in Sentinel-2 GRI geolocation performance assessment whose results will be presented in this paper. The GRI is a set of S2A images at 10m resolution covering the whole world with a good and consistent geolocation. This ground reference enables accurate multi-temporal registration of refined Sentinel-2 products. While not primarily intended for the generation of DSM, Sentinel-2 swaths overlap between orbits would also allow for the generation of a complete DSM of land and ices over 60° of northern latitudes (expected accuracy: few S2 pixels in altimetry). This DSM would benefit from the very frequent revisit times of Sentinel-2, to monitor ice or snow level in area of frequent changes, or to increase measurement accuracy in areas of little changes.

  4. Solid State Digital Propulsion "Cluster Thrusters" For Small Satellites Using High Performance Electrically Controlled Extinguishable Solid Propellants (ECESP)

    Science.gov (United States)

    Sawka, Wayne N.; Katzakian, Arthur; Grix, Charles

    2005-01-01

    Electrically controlled extinguishable solid propellants (ESCSP) are capable of multiple ignitions, extinguishments and throttle control by the application of electrical power. Both core and end burning no moving parts ECESP grains/motors to three inches in diameter have now been tested. Ongoing research has led to a newer family of even higher performance ECESP providing up to 10% higher performance, manufacturing ease, and significantly higher electrical conduction. The high conductivity was not found to be desirable for larger motors; however it is ideal for downward scaling to micro and pico- propulsion applications with a web thickness of less than 0.125 inch/ diameter. As a solid solution propellant, this ECESP is molecularly uniform, having no granular structure. Because of this homogeneity and workable viscosity it can be directly cast into thin layers or vacuum cast into complex geometries. Both coaxial and grain stacks have been demonstrated. Combining individual propellant coaxial grains and/or grain stacks together form three-dimensional arrays yield modular cluster thrusters. Adoption of fabless manufacturing methods and standards from the electronics industry will provide custom, highly reproducible micro-propulsion arrays and clusters at low costs. These stack and cluster thruster designs provide a small footprint saving spacecraft surface area for solar panels and/or experiments. The simplicity of these thrusters will enable their broad use on micro-pico satellites for primary propulsion, ACS and formation flying applications. Larger spacecraft may find uses for ECESP thrusters on extended booms, on-orbit refueling, pneumatic actuators, and gas generators.

  5. Computer-aided detection system performance on current and previous digital mammograms in patients with contralateral metachronous breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Ja (Dept. of Radiology, Seoul Metropolitan Government - Seoul National Univ. Boramae Medical Center, Seoul (Korea, Republic of)); Moon, Woo Kyung; Cho, Nariya; Chang, Jung Min (Dept. of Radiology, Seoul National Univ. Hospital, Seoul (Korea, Republic of)), email: moonwk@snu.ac.kr

    2012-05-15

    Background: The computer-aided detection (CAD) system is widely used for screening mammography. The performance of the CAD system for contralateral breast cancer has not been reported for women with a history of breast cancer. Purpose: To retrospectively evaluate the performance of a CAD system on current and previous mammograms in patients with contralateral metachronous breast cancer. Material and Methods: During a 3-year period, 4945 postoperative patients had follow-up examinations, from whom we selected 55 women with contralateral breast cancers. Among them, 38 had visible malignant signs on the current mammograms. We analyzed the sensitivity and false-positive marks of the system on the current and previous mammograms according to lesion type and breast density. Results: The total visible lesion components on the current mammograms included 27 masses and 14 calcifications in 38 patients. The case-based sensitivity for all lesion types was 63.2% (24/38) with false-positive marks of 0.71 per patient. The lesion-based sensitivity for masses and calcifications was 59.3% (16/27) and 71.4% (10/14), respectively. The lesion-based sensitivity for masses in fatty and dense breasts was 68.8% (11/16) and 45.5% (5/11), respectively. The lesion-based sensitivity for calcifications in fatty and dense breasts was 100.0% (3/3) and 63.6% (7/11), respectively. The total visible lesion components on the previous mammograms included 13 masses and three calcifications in 16 patients, and the sensitivity for all lesion types was 31.3% (5/16) with false-positive marks of 0.81 per patient. On these mammograms, the sensitivity for masses and calcifications was 30.8% (4/13) and 33.3% (1/3), respectively. The sensitivity in fatty and dense breasts was 28.6% (2/7) and 33.3% (3/9), respectively. Conclusion: In the women with a history of breast cancer, the sensitivity of the CAD system in visible contralateral breast cancer was lower than in most previous reports using the same CAD

  6. Digital Leadership

    DEFF Research Database (Denmark)

    Zupancic, Tadeja; Verbeke, Johan; Achten, Henri

    2016-01-01

    . With this paper we intend to initiate a discussion in the eCAADe community to reflect and develop ideas in order to develop digital leadership skills amongst the membership. This paper introduces some important aspects, which may be valuable to look into when developing digital leadership skills.......Leadership is an important quality in organisations. Leadership is needed to introduce change and innovation. In our opinion, in architectural and design practices, the role of leadership has not yet been sufficiently studied, especially when it comes to the role of digital tools and media...

  7. Digital holography

    CERN Document Server

    Picart, Pascal

    2013-01-01

    This book presents a substantial description of the principles and applications of digital holography.The first part of the book deals with mathematical basics and the linear filtering theory necessary to approach the topic. The next part describes the fundamentals of diffraction theory and exhaustively details the numerical computation of diffracted fields using FFT algorithms. A thorough presentation of the principles of holography and digital holography, including digital color holography, is proposed in the third part.A special section is devoted to the algorithms and method

  8. Digital electronics

    CERN Document Server

    Morris, John

    2013-01-01

    An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

  9. DIGITAL ASSESSMENTS

    OpenAIRE

    Nielsen, Kurt Gammelgaard; Petersen, Lise

    2013-01-01

    In accordance with The Danish eGOVERNMENT strategy 2011-2015 digital assessment and exam should be implemented at all Danish universities by the end of 2013. University of Southern Denmark (SDU) decided to start the implementation in May 2010.By the exam term of January 2013, the implementation proved successful, and close to completion. The majority of assessments at all of the 5 faculties and 5 campuses were digital, and students had handed in a total of 17.021 digital assessments.On the ba...

  10. Digital Leadership

    DEFF Research Database (Denmark)

    Zupancic, Tadeja; Verbeke, Johan; Achten, Henri

    2016-01-01

    Leadership is an important quality in organisations. Leadership is needed to introduce change and innovation. In our opinion, in architectural and design practices, the role of leadership has not yet been sufficiently studied, especially when it comes to the role of digital tools and media....... With this paper we intend to initiate a discussion in the eCAADe community to reflect and develop ideas in order to develop digital leadership skills amongst the membership. This paper introduces some important aspects, which may be valuable to look into when developing digital leadership skills....

  11. Digital Insights

    DEFF Research Database (Denmark)

    Knudsen, Gry Høngsmark

    and practices with digital media, when they meet and interpret advertising. Through studies of advertising response on YouTube and experiments with consumers’ response to digitally manipulated images, the dissertation shows how digital media practices facilitate polysemic and socially embedded advertising......, by incorporating media as both channel, frame, and apparatus for advertising response, the dissertation brings into attention that more aspects than the text-reader relationship influence ad response. Finally, the dissertation proposes the assemblage approach for exploring big data in consumer culture research...

  12. The Influence of Collaboration Styles to Children's Cognitive Performance in Digital Problem-Solving Game "William Adventure": A Comparative Case Study

    Science.gov (United States)

    Shih, Ju-Ling; Shih, Bai-Jiun; Shih, Chun-Chao; Su, Hui-Yu; Chuang, Chien-Wen

    2010-01-01

    Since a large variety of digital games have been used in many fields for educational purposes, their real functions in learning have caught much attention as well. This study first defines learning characteristics of problem-solving digital games and their corresponding cognitive levels, then designs and develops a problem-solving game in…

  13. Digital fabrication

    CERN Document Server

    2012-01-01

    The Winter 2012 (vol. 14 no. 3) issue of the Nexus Network Journal features seven original papers dedicated to the theme “Digital Fabrication”. Digital fabrication is changing architecture in fundamental ways in every phase, from concept to artifact. Projects growing out of research in digital fabrication are dependent on software that is entirely surface-oriented in its underlying mathematics. Decisions made during design, prototyping, fabrication and assembly rely on codes, scripts, parameters, operating systems and software, creating the need for teams with multidisciplinary expertise and different skills, from IT to architecture, design, material engineering, and mathematics, among others The papers grew out of a Lisbon symposium hosted by the ISCTE-Instituto Universitario de Lisboa entitled “Digital Fabrication – A State of the Art”. The issue is completed with four other research papers which address different mathematical instruments applied to architecture, including geometric tracing system...

  14. Digital Humanities

    DEFF Research Database (Denmark)

    Brügger, Niels

    2016-01-01

    the humanities for decades, starting with research fields such as humanities computing or computational linguistics in the 1950s, and later new media studies and internet studies. The historical development of digital humanities has been characterized by a focus on three successive, but co-existing types......Digital humanities is an umbrella term for theories, methodologies, and practices related to humanities scholarship that use the digital computer as an integrated and essential part of its research and teaching activities. The computer can be used for establishing, finding, collecting......, and preserving material to study, as an object of study in its own right, as an analytical tool, or for collaborating, and for disseminating results. The term "digital humanities" was coined around 2001, and gained currency within academia in the following years. However, computers had been used within...

  15. Digital Snaps

    DEFF Research Database (Denmark)

    Sandbye, Mette; Larsen, Jonas

    The New Face of Snapshot Photography / Jonas Larsen and Mette Sandbye -- pt. I. IMAGES ON WEB 2.0 AND THE CAMERA PHONE -- ch. 1. Overlooking, Rarely Looking and Not Looking / Martin Lister -- ch. 2. The (Im)mobile Life of Digital Photographs: The Case of Tourist Photography / Jonas Larsen -- ch. 3....... Distance as the New Punctum / Mikko Villi -- pt. II. FAMILY ALBUMS IN TRANSITION -- ch. 4. How Digital Technologies Do Family Snaps, Only Better / Gillian Rose -- ch. 5. Friendship Photography: Memory, Mobility and Social Networking / Joanne Garde-Hansen -- ch. 6. Play, Process and Materiality in Japanese...... Purikura Photography / Mette Sandbye -- ch. 7. 'Buying an Instrument Does Not Necessarily Make You a Musician': Studio Photography and the Digital Revolution / Sigrid Lien -- pt. III. NEW PUBLIC FORMS -- ch. 8 Paparazzi Photography, Seriality and the Digital Photo Archive / Anne Jerslev and Mette Mortensen...

  16. Becoming digital

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2015-01-01

    The purpose of this paper is to examine the impact of e-government reforms on street-level bureaucrats’ professionalism and relation to citizens, thus demonstrating how the bureaucratic encounter unfolds in the digital era. Design/methodology/approach: The paper is based on an ethnographic study....... An ethnographic account of how digital reforms are implemented in practice shows how street-level bureaucrat’s classic tasks such as specialized casework are being reconfigured into educational tasks that promote the idea of “becoming digital”. In the paper, the author argues that the work of “becoming digital....... Originality/value: The study contributes to ethnographic research in public administration by combining two separate subfields, e-government and street-level bureaucracy, to discern recent transformations in public service delivery. In the digital era, tasks, control and equality are distributed in ways...

  17. Digital Steganography

    OpenAIRE

    KOCIÁNOVÁ, Helena

    2009-01-01

    Digital steganography is a technique for hiding data mostly into multimedia files (images, audio, video). With the development of information technology this technique has found its use in the field of copyright protection and secret data transfer, could be even applied in places where is limited possibility of using cryptography (e. g. by law). This thesis gives insight into digital steganography and contains an application using this technique.

  18. Digital watermark

    OpenAIRE

    Jasna Maver

    2004-01-01

    The huge amount of multimedia contents available on the World-Wide-Web is beginning to raise the question of their protection. Digital watermarking is a technique which can serve various purposes, including intellectual property protection, authentication and integrity verification, as well as visible or invisible content labelling of multimedia content. Due to the diversity of digital watermarking applicability, there are many different techniques, which can be categorised according to diffe...

  19. Digital chest radiography

    DEFF Research Database (Denmark)

    Debess, Jeanne Elisabeth; Johnsen, Karen Kirstine; Thomsen, Henrik

    2015-01-01

    Background: Chest radiography is one of the most common examinations in radiology departments. In 2013 approximately 80,000 chest x-rays were performed on women in the fertile age. Even low dose for the examinationCorrect collimation Purpose: Quality improvement of basic radiography focusing...... collimations depending on side of radiograph. Results from dose reduction will be presented on the congress Conclusion: Correct positioning and collimation of digital chest radiographs can reduce the radiation dose significant to the patients and by that improve the quality of basic radiography....... on collimation and dose reduction in digital chest radiography Methods and Materials A retrospective study of digital chest radiography is performed to evaluate the primary x-ray tube collimation of the PA and lateral radiographs. Data from one hundred fifty self-reliant female patients between 15 and 55 years...

  20. Digital Actuator Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ken Thomas; Ted Quinn; Jerry Mauck; Richard Bockhorst

    2014-09-01

    There are significant developments underway in new types of actuators for power plant active components. Many of these make use of digital technology to provide a wide array of benefits in performance of the actuators and in reduced burden to maintain them. These new product offerings have gained considerable acceptance in use in process plants. In addition, they have been used in conventional power generation very successfully. This technology has been proven to deliver the benefits promised and substantiate the claims of improved performance. The nuclear industry has been reluctant to incorporate digital actuator technology into nuclear plant designs due to concerns due to a number of concerns. These could be summarized as cost, regulatory uncertainty, and a certain comfort factor with legacy analog technology. The replacement opportunity for these types of components represents a decision point for whether to invest in more modern technology that would provide superior operational and maintenance benefits. Yet, the application of digital technology has been problematic for the nuclear industry, due to qualification and regulatory issues. With some notable exceptions, the result has been a continuing reluctance to undertake the risks and uncertainties of implementing digital actuator technology when replacement opportunities present themselves. Rather, utilities would typically prefer to accept the performance limitations of the legacy analog actuator technologies to avoid impacts to project costs and schedules. The purpose of this report is to demonstrate that the benefits of digital actuator technology can be significant in terms of plant performance and that it is worthwhile to address the barriers currently holding back the widespread development and use of this technology. It addresses two important objectives in pursuit of the beneficial use of digital actuator technology for nuclear power plants: 1. To demonstrate the benefits of digital actuator

  1. 3D digitization of mosaics

    Directory of Open Access Journals (Sweden)

    Anna Maria Manferdini

    2012-11-01

    Full Text Available In this paper we present a methodology developed to access to Cultural Heritage information using digital 3d reality-based models as graphic interfaces. The case studies presented belong to the wide repertoire of mosaics of Ravenna. One of the most peculiar characteristics of mosaics that often limits their digital survey is their multi-scale complexity; nevertheless their models could be used in 3d information systems, for digital exhibitions, for reconstruction aims and to document their conservation conditions in order to conduct restoration interventions in digital environments aiming at speeding and performing more reliable evaluations.

  2. Evaluating the Performance of High-Altitude Aerial Image-Based Digital Surface Models in Detecting Individual Tree Crowns in Mature Boreal Forests

    Directory of Open Access Journals (Sweden)

    Topi Tanhuanpää

    2016-07-01

    Full Text Available Height models based on high-altitude aerial images provide a low-cost means of generating detailed 3D models of the forest canopy. In this study, the performance of these height models in the detection of individual trees was evaluated in a commercially managed boreal forest. Airborne digital stereo imagery (DSI was captured from a flight altitude of 5 km with a ground sample distance of 50 cm and corresponds to regular national topographic airborne data capture programs operated in many countries. Tree tops were detected from smoothed canopy height models (CHM using watershed segmentation. The relative amount of detected trees varied between 26% and 140%, and the RMSE of plot-level arithmetic mean height between 2.2 m and 3.1 m. Both the dominant tree species and the filter used for smoothing affected the results. Even though the spatial resolution of DSI-based CHM was sufficient, detecting individual trees from the data proved to be demanding because of the shading effect of the dominant trees and the limited amount of data from lower canopy levels and near the ground.

  3. Performance of Droplet Digital PCR in Non-Invasive Fetal RHD Genotyping - Comparison with a Routine Real-Time PCR Based Approach.

    Directory of Open Access Journals (Sweden)

    Iveta Svobodová

    Full Text Available Detection and characterization of circulating cell-free fetal DNA (cffDNA from maternal circulation requires an extremely sensitive and precise method due to very low cffDNA concentration. In our study, droplet digital PCR (ddPCR was implemented for fetal RHD genotyping from maternal plasma to compare this new quantification alternative with real-time PCR (qPCR as a golden standard for quantitative analysis of cffDNA. In the first stage of study, a DNA quantification standard was used. Clinical samples, including 10 non-pregnant and 35 pregnant women, were analyzed as a next step. Both methods' performance parameters-standard curve linearity, detection limit and measurement precision-were evaluated. ddPCR in comparison with qPCR has demonstrated sufficient sensitivity for analysing of cffDNA and determination of fetal RhD status from maternal circulation, results of both methods strongly correlated. Despite the more demanding workflow, ddPCR was found to be slightly more precise technology, as evaluated using quantitative standard. Regarding the clinical samples, the precision of both methods equalized with decreasing concentrations of tested DNA samples. In case of cffDNA with very low concentrations, variance parameters of both techniques were comparable. Detected levels of fetal cfDNA in maternal plasma were slightly higher than expected and correlated significantly with gestational age as measured by both methods (ddPCR r = 0.459; qPCR r = 0.438.

  4. Fotografia na era digital: produção, protagonismo e performance – problemas para a Educação Física/Ciências do Esporte

    Directory of Open Access Journals (Sweden)

    Fernando Gonçalves Bitencourt

    2014-11-01

    Full Text Available http://dx.doi.org/10.5007/2175-8042.2014v26n43p198 Este texto, fruto das observações oriundas de “micro” etnografias realizadas durante estágio de doutorado em Madri, reflete sobre a fotografia, tomada por agentes sociais distintos, de desportistas e espaços desportivos na era digital. Considerando a profusão de imagens e a facilidade de difusão via internet, questiona implicações ético-morais da captura destas e os sentidos da produção, protagonismo e performances. Sugiro haver ‘gosto de class’ e ‘habitus’ a orientar estas práticas. A apropriação da imagem alheia (de ídolos e anônimos e a exacerbação do individualismo caracterizam este ‘ethos’, cujo perigo reside no uso privado e na publicização inconsequente da vida alheia.

  5. Digital filter synthesis computer program

    Science.gov (United States)

    Moyer, R. A.; Munoz, R. M.

    1968-01-01

    Digital filter synthesis computer program expresses any continuous function of a complex variable in approximate form as a computational algorithm or difference equation. Once the difference equation has been developed, digital filtering can be performed by the program on any input data list.

  6. 数字档案馆绩效评估中引入BSC的必要性与适用性%The Necessity and Applicability When Introducing BSC to the Digital Archives of the Performance Evaluation

    Institute of Scientific and Technical Information of China (English)

    颜丙通

    2014-01-01

    BSC是组织战略管理与绩效评估的重要工具之一,将其引入数字档案馆绩效评估中有现实必要性与客观适用性。%BSC is one of the important tools of organization strategy management and performance evaluation, introducing BSC to the digital archives of the performance evaluation is necessary and suitable.

  7. Can the evaluation of a simple test object be used to predict the performance of a contrast-detail analysis in digital mammography?

    Science.gov (United States)

    Bosmans, H.; Lemmens, K.; Jacobs, J.; Vandenbroucke, D.; Zanca, F.; Michielsen, K.; Verbrugge, B.; Smans, K.; Marchal, G.

    2009-02-01

    The purpose was to find the correlation between a Figure of Merit (FoM) calculated from a new (simple) test object for Quality Control in digital mammography and CDMAM threshold thicknesses. The FoM included the signal difference to noise ratio, modulation transfer function of the complete system (including scatter and grid) and normalized noise power spectrum. The pre-programmed exposure settings for clinical work were used, as was done for the CDMAM acquisitions. The FoM is calculated from 2 images only (an image from the QC test object and an image of a corresponding homogeneous plate imaged with the same exposure settings). This FoM was evaluated in frequencies that match with the diameters of the gold disks in the CDMAM phantom. Computerized CDMAM analysis uses 16 images per system. The software program "cdcom" (www.euref.org) was used for the 4-AFC experiment. All matrices were averaged, smoothed with a Gaussian filter and psychometric curves were fitted through the correctly detected fractions to obtain the threshold thickness with a detectability of 62.5% for all diameters. Images have been acquired on 10 different systems (2 computed radiography (CR) systems, 6 direct radiology (DR) systems and 2 photon counting systems). The reproducibility of the QC metrics from images of the new phantom was assessed. The standard error on the mean of the FoM was for the highest frequency 8.1% for a CR system and 5.6% for a DR system. The main component in this error is due to the NNPS and the limited number of independent pixels used in this analysis. Parameters calculated from both phantoms are sensitive to variation in mean glandular dose levels. Present results show a weak correlation (R2=0.60) between the FoM at 5lp/mm and CDMAM threshold values for the 0.1mm objects when all system data are pooled. If evaluated for separate systems, the correlation holds promise for automated, periodic performance evaluations of digital mammography systems with the simplified

  8. SAFARI digital processing unit: performance analysis of the SpaceWire links in case of a LEON3-FT based CPU

    Science.gov (United States)

    Giusi, Giovanni; Liu, Scige J.; Di Giorgio, Anna M.; Galli, Emanuele; Pezzuto, Stefano; Farina, Maria; Spinoglio, Luigi

    2014-08-01

    SAFARI (SpicA FAR infrared Instrument) is a far-infrared imaging Fourier Transform Spectrometer for the SPICA mission. The Digital Processing Unit (DPU) of the instrument implements the functions of controlling the overall instrument and implementing the science data compression and packing. The DPU design is based on the use of a LEON family processor. In SAFARI, all instrument components are connected to the central DPU via SpaceWire links. On these links science data, housekeeping and commands flows are in some cases multiplexed, therefore the interface control shall be able to cope with variable throughput needs. The effective data transfer workload can be an issue for the overall system performances and becomes a critical parameter for the on-board software design, both at application layer level and at lower, and more HW related, levels. To analyze the system behavior in presence of the expected SAFARI demanding science data flow, we carried out a series of performance tests using the standard GR-CPCI-UT699 LEON3-FT Development Board, provided by Aeroflex/Gaisler, connected to the emulator of the SAFARI science data links, in a point-to-point topology. Two different communication protocols have been used in the tests, the ECSS-E-ST-50-52C RMAP protocol and an internally defined one, the SAFARI internal data handling protocol. An incremental approach has been adopted to measure the system performances at different levels of the communication protocol complexity. In all cases the performance has been evaluated by measuring the CPU workload and the bus latencies. The tests have been executed initially in a custom low level execution environment and finally using the Real- Time Executive for Multiprocessor Systems (RTEMS), which has been selected as the operating system to be used onboard SAFARI. The preliminary results of the carried out performance analysis confirmed the possibility of using a LEON3 CPU processor in the SAFARI DPU, but pointed out, in agreement

  9. Digital Humanities and networked digital media

    OpenAIRE

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no ...

  10. Orofacial digital syndrome

    Directory of Open Access Journals (Sweden)

    Kajal V Dave

    2013-01-01

    Full Text Available A case of a 10-year-old boy reported to us for delayed eruption of permanent teeth with classical features of orofacial digital syndrome (OFDS. The case of OFDS is being reported and the various clinico-radiological features of both type I and type II are compared. Chromosomal karyotyping of the case has also been performed.

  11. Digital watermark

    Directory of Open Access Journals (Sweden)

    Jasna Maver

    2000-01-01

    Full Text Available The huge amount of multimedia contents available on the World-Wide-Web is beginning to raise the question of their protection. Digital watermarking is a technique which can serve various purposes, including intellectual property protection, authentication and integrity verification, as well as visible or invisible content labelling of multimedia content. Due to the diversity of digital watermarking applicability, there are many different techniques, which can be categorised according to different criteria. A digital watermark can be categorised as visible or invisible and as robust or fragile. In contrast to the visible watermark where a visible pattern or image is embedded into the original image, the invisible watermark does not change the visual appearance of the image. The existence of such a watermark can be determined only through a watermark ex¬traction or detection algorithm. The robust watermark is used for copyright protection, while the fragile watermark is designed for authentication and integrity verification of multimedia content. A watermark must be detectable or extractable to be useful. In some watermarking schemes, a watermark can be extracted in its exact form, in other cases, we can detect only whether a specific given watermarking signal is present in an image. Digital libraries, through which cultural institutions will make multimedia contents available, should support a wide range of service models for intellectual property protection, where digital watermarking may play an important role.

  12. Digital Humanities and networked digital media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...

  13. Digital computers in action

    CERN Document Server

    Booth, A D

    1965-01-01

    Digital Computers in Action is an introduction to the basics of digital computers as well as their programming and various applications in fields such as mathematics, science, engineering, economics, medicine, and law. Other topics include engineering automation, process control, special purpose games-playing devices, machine translation and mechanized linguistics, and information retrieval. This book consists of 14 chapters and begins by discussing the history of computers, from the idea of performing complex arithmetical calculations to the emergence of a modern view of the structure of a ge

  14. CEA SMAD 2016 Digitizer Evaluation.

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, Bion J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-08-01

    Sandia National Laboratories has tested and evaluated an updated SMAD digitizer, developed by the French Alternative Energies and Atomic Energy Commission (CEA). The SMAD digitizers are intended to record sensor output for seismic and infrasound monitoring applications. The purpose of this digitizer evaluation is to measure the performance characteristics in such areas as power consumption, input impedance, sensitivity, full scale, self-noise, dynamic range, system noise, response, passband, and timing. The SMAD digitizers have been updated since their last evaluation by Sandia to improve their performance when recording at a sample rate of 20 Hz for infrasound applications and 100 Hz for hydro-acoustic seismic stations. This evaluation focuses primarily on the 20 Hz and 100 Hz sample rates. The SMAD digitizers are being evaluated for potential use in the International Monitoring System (IMS) of the Comprehensive Nuclear Test- Ban-Treaty Organization (CTBTO).

  15. Digital Relationships

    DEFF Research Database (Denmark)

    Ledborg Hansen, Richard

    -­‐Jones, 2011) for increases in effectiveness and efficiency we indiscriminately embrace digital communication and digitized information dissemination with enthusiasm – at the risk of ignoring the potentially dark side of technology. However, technology also holds a promise for better understanding precisely...... of residual deposits from technology in organizations and its effect on individuals ability to connect to one another. Based on the case study the paper describes indications and suggests potential implication hereof. Given the inherent enhancement possibilities of technology our expectation for entertainment......-­rich information and highly interesting communication are sky-­high and rising. With a continuous increase in digitized communication follows a decrease in face-­to-­face encounters and our ability to engage in inter-­personal relationships are suffering for it (Davis, 2013). The behavior described in this paper...

  16. Digital Creativity

    DEFF Research Database (Denmark)

    Petersson Brooks, Eva; Brooks, Anthony Lewis

    2014-01-01

    This paper reports on a study exploring the outcomes from children’s play with technology in early childhood learning practices. The paper addresses questions related to how digital technology can foster creativity in early childhood learning environments. It consists of an analysis of children......’s interaction with the KidSmart furniture focusing on digital creativity potentials and play values suggested by the technology. The study applied a qualitative approach and included125 children (aged three to five), 10 pedagogues, and two librarians. The results suggests that educators should sensitively...... consider intervening when children are interacting with technology, and rather put emphasize into the integration of the technology into the environment and to the curriculum in order to shape playful structures for children’s digital creativity....

  17. Fotografia digital

    OpenAIRE

    Vinicius Cauduro, Flávio; Pontifícia Universidade Católica do Rio Grande do Sul

    2008-01-01

    Poderíamos talvez definir como sendo fotografia digital toda e qualquer imagem obtida a partir de uma camera obscura, com características ótico-mecânicas variáveis através de princípios puramente analógicos ou por combinação híbrida (analógico/digital), e que seja posteriormente processada em computador e exibida de forma projetada (monitor ou tela) ou imprensa (papel ou filme).

  18. Digital photogrammetry

    CERN Document Server

    Egels, Yves

    2003-01-01

    Photogrammetry is the use of photography for surveying primarily and is used for the production of maps from aerial photographs. Along with remote sensing, it represents the primary means of generating data for Geographic Information Systems (GIS). As technology develops, it is becoming easier to gain access to it. The cost of digital photogrammetric workstations are falling quickly and these new tools are therefore becoming accessible to more and more users. Digital Photogrammetry is particularly useful as a text for graduate students in geomantic and is also suitable for people with a good basic scientific knowledge who need to understand photogrammetry, and who wish to use the book as a reference.

  19. Digital literacies

    CERN Document Server

    Hockly, Nicky; Pegrum, Mark

    2014-01-01

    Dramatic shifts in our communication landscape have made it crucial for language teaching to go beyond print literacy and encompass the digital literacies which are increasingly central to learners' personal, social, educational and professional lives. By situating these digital literacies within a clear theoretical framework, this book provides educators and students alike with not just the background for a deeper understanding of these key 21st-century skills, but also the rationale for integrating these skills into classroom practice. This is the first methodology book to address not jus

  20. Digital communication

    CERN Document Server

    Das, Apurba

    2010-01-01

    ""Digital Communications"" presents the theory and application of the philosophy of Digital Communication systems in a unique but lucid form. This book inserts equal importance to the theory and application aspect of the subject whereby the authors selected a wide class of problems. The Salient features of the book are: the foundation of Fourier series, Transform and wavelets are introduces in a unique way but in lucid language; the application area is rich and resemblance to the present trend of research, as we are attached with those areas professionally; a CD is included which contains code

  1. Digital filters

    CERN Document Server

    Hamming, Richard W

    1997-01-01

    Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s

  2. Building digital collections: An evaluation

    Digital Repository Service at National Institute of Oceanography (India)

    Tapaswi, M.P.

    . This individual/group is also normally responsible for the functions that pertain to the digital library (like search and retrieval, system performance and feedback). The advantages of the individual/ group monitoring input are: • Designated responsibility...

  3. Performative Tectonics

    DEFF Research Database (Denmark)

    Holst, Malene Kirstine; Mullins, Michael; Kirkegaard, Poul Henning

    2010-01-01

    This paper studies two digital generative tools in terms of Performative Tectonics. Performative Tectonics is a term developed in the paper, which links the contemporary development of digital tools to the tectonic tradition of architecture. Within the theoretical framework of this definition...

  4. Digitalization Boosting Novel Digital Services for Consumers

    Directory of Open Access Journals (Sweden)

    Kaisa Vehmas

    Full Text Available Digitalization has changed the world. The digital revolution has promoted the Internet, and more recently mobile network infrastructure, as the technological backbone of our society. Digital technologies have become more integrated across all sectors of o ...

  5. Fast Digit-Index Permutations

    Directory of Open Access Journals (Sweden)

    Dorothy Bollman

    1996-01-01

    Full Text Available We introduce a tensor sum which is useful for the design and analysis of digit-index permutations (DIPs algorithms. Using this operation we obtain a new high-performance algorithm for the family of DIPs. We discuss an implementation in the applicative language Sisal and show how different choices of parameters yield different DIPs. The efficiency of the special case of digit reversal is illustrated with performance results on a Cray C-90.

  6. Digital Methods

    NARCIS (Netherlands)

    Rogers, R.

    2013-01-01

    In Digital Methods, Richard Rogers proposes a methodological outlook for social and cultural scholarly research on the Web that seeks to move Internet research beyond the study of online culture. It is not a toolkit for Internet research, or operating instructions for a software package; it deals wi

  7. Digital Tidbits

    Science.gov (United States)

    Kumaran, Maha; Geary, Joe

    2011-01-01

    Technology has transformed libraries. There are digital libraries, electronic collections, online databases and catalogs, ebooks, downloadable books, and much more. With free technology such as social websites, newspaper collections, downloadable online calendars, clocks and sticky notes, online scheduling, online document sharing, and online…

  8. Digital Tidbits

    Science.gov (United States)

    Kumaran, Maha; Geary, Joe

    2011-01-01

    Technology has transformed libraries. There are digital libraries, electronic collections, online databases and catalogs, ebooks, downloadable books, and much more. With free technology such as social websites, newspaper collections, downloadable online calendars, clocks and sticky notes, online scheduling, online document sharing, and online…

  9. Digital radiography

    DEFF Research Database (Denmark)

    Precht, H; Gerke, O; Rosendahl, K

    2012-01-01

    BACKGROUND: New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults...

  10. Digital books.

    Science.gov (United States)

    Wink, Diane M

    2011-01-01

    In this bimonthly series, the author examines how nurse educators can use the Internet and Web-based computer technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes digital books.

  11. Digital forvaltning

    DEFF Research Database (Denmark)

    Remmen, Arne; Larsen, Torben; Mosgaard, Mette

    2004-01-01

    Større effektivitet, bedre service og mere demokrai er blot nogle af forventningerne til indførelse af digital forveltning i kommunerne. Kapitlet giver bland andet svar på spørgsmålene : Hvordan lever kommunerne op hertil i dagligdagen? hvilke virkemidler anvender de? Hvilke barrierer har der været...

  12. Digital Batteries

    Science.gov (United States)

    Hubler, Alfred

    2009-03-01

    The energy density in conventional capacitors is limited by sparking. We present nano-capacitor arrays, where - like in laser diodes and quantum wells [1] - quantization prevents dielectric breakthrough. We show that the energy density and the power/weight ratio are very high, possibly larger than in hydrogen [2]. Digital batteries are a potential clean energy source for cars, laptops, and mobile devices. The technology is related to flash drives. However, because of the high energy density, safety is a concern. Digital batteries can be easily and safely charged and discharged. In the discharged state they pose no danger. Even if a charged digital battery were to explode, it would produce no radioactive waste, no long-term radiation, and probably could be designed to produce no noxious chemicals. We discuss methodologies to prevent shorts and other measures to make digital batteries safe. [1] H. Higuraskh, A. Toriumi, F. Yamaguchi, K. Kawamura, A. Hubler, Correlation Tunnel Device, U. S. Patent No. 5,679,961 (1997) [2] Alfred Hubler, http://server10.how-why.com/blog/

  13. Fokus: Digital

    DEFF Research Database (Denmark)

    2014-01-01

    sammenhænge og fra forandrede distributionsformer. Dette betyder ændrede betingelser for både produktion og reception af kunstmusik og lydkunst. Med Digital tager vi udgangspunkt i fire komponisters meget forskellige bud på hvordan teknologien spiller en rolle i arbejdet. Juliana Hodkinson beskriver hvordan...

  14. Cost Model for Digital Curation: Cost of Digital Migration

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

    2009-01-01

    The Danish Ministry of Culture is currently funding a project to set up a model for costing preservation of digital materials held by national cultural heritage institutions. The overall objective of the project is to provide a basis for comparing and estimating future financial requirements...... for digital preservation and to increase cost effectiveness of digital preservation activities. In this study we describe an activity based costing methodology for digital preservation based on the OAIS Reference Model. In order to estimate the cost of digital migrations we have identified cost critical...... model provides a sound overall framework for cost breakdown, but that some functions, especially when it comes to performing and evaluating the actual migration, need additional detailing in order to cost activities accurately....

  15. Task-based performance analysis of FBP, SART and ML for digital breast tomosynthesis using signal CNR and Channelised Hotelling Observers.

    Science.gov (United States)

    Van de Sompel, Dominique; Brady, Sir Michael; Boone, John

    2011-02-01

    We assess the performance of filtered backprojection (FBP), the simultaneous algebraic reconstruction technique (SART) and the maximum likelihood (ML) algorithm for digital breast tomosynthesis (DBT) under variations in key imaging parameters, including the number of iterations, number of projections, angular range, initial guess, and radiation dose. This is the first study to compare these algorithms for the application of DBT. We present a methodology for the evaluation of DBT reconstructions, and use it to conduct preliminary experiments investigating trade-offs between the selected imaging parameters. This investigation includes trade-offs not previously considered in the DBT literature, such as the use of a stationary detector versus a C-arm imaging geometry. A real breast CT volume serves as a ground truth digital phantom from which to simulate X-ray projections under the various acquisition parameters. The reconstructed image quality is measured using task-based metrics, namely signal CNR and the AUC of a Channelised Hotelling Observer with Laguerre-Gauss basis functions. The task at hand is the detection of a simulated mass inserted into the breast CT volume. We find that the image quality in limited view tomography is highly dependent on the particular acquisition and reconstruction parameters used. In particular, we draw the following conclusions. First, we find that optimising the FBP filter design and SART relaxation parameter yields significant improvements in reconstruction quality from the same projection data. Second, we show that the convergence rate of the maximum likelihood algorithm, optimised with paraboloidal surrogates and conjugate gradient ascent (ML-PSCG), can be greatly accelerated using view-by-view updates. Third, we find that the optimal initial guess is algorithm dependent. In particular, we obtained best results with a zero initial guess for SART, and an FBP initial guess for ML-PSCG. Fourth, when the exposure per view is constant

  16. Digital Humanities and networked digital media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...

  17. Digital Plasmonics

    CERN Document Server

    Gjonaj, Bergin; Johnson, Patrick M; Mosk, Allard P; Kuipers, Kobus; Lagendijk, Ad

    2010-01-01

    The field of plasmonics offers a route to control light fields with metallic nanostructures through the excitation of Surface Plasmon Polaritons (SPPs). These surface waves, bound to a metal dielectric interface, tightly confine electromagnetic energy. Active control over SPPs has potential for applications in sensing, photovoltaics, quantum communication, nano circuitry, metamaterials and super-resolution microscopy. We achieve here a new level of control of plasmonic fields using a digital spatial light modulator. Optimizing the plasmonic phases via feedback we focus SPPs at a freely pre-chosen point on the surface of a nanohole array with high resolution. Digital addressing and scanning of SPPs without mechanical motion will enable novel interdisciplinary applications of advanced plasmonic devices in cell microscopy, optical data storage and sensing.

  18. Digital tachometer

    Science.gov (United States)

    Shirokov, B.

    1984-03-01

    A tachometer with digital indication was built for measuring the speed of automobile engines with only two digits in the rpm readout. It consists of a Schmitt trigger for shaping input pulses, a pulse counter, a cycle time setting multivibrator and a readout time setting multivibrator, a stabilizer, a flicker suppressor, and a capacitive transducer. The instrument operates from a 12 V battery and draws 180 mA. The transducer includes a 30 to 50 turns coil of PEL 0.5 wire wound around the conductor which connects the ignition coil to the engine distributor and its transistor is mounted on a fin-type heat sink. Tuneup of the tachometer involves matching the transducer capacitor for maximum voltage at minimum current and trimming the readout time setting multivibrator with its adjustable resistor for a 1.5 readout with a 50 Hz input signal.

  19. Digital resources

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2005-12-01

    Full Text Available Bibliotheca Latinitatis Mediaevalis (circa VII sec. - XIV sec. IntraText Digital Library [01/06] Corpus Scriptorum Latinorum. A digital library of Latin literature by David Camden [01/06] Fonti disponibili online concernenti la vita religiosa medievale Rete Vitae Religiosae Mediaevalis Studia Conectens [01/06] Fuentes del Medievo Hispanico Instituto de Historia, Consejo Superior de Investigaciones Científicas [01/06] Latin Literature Forum Romanum [01/06] Ludovico Antonio Muratori, Dissertazioni sopra le antichità italiane, 1751 Biblioteca dei Classici Italiani di Giuseppe Bonghi [01/06] Medieval Latin The Latin Library [01/06] Médiévales Presses Universitaires de Vincennes - Revues.org [01/06] Regesta imperii Deutsche Kommission für die Bearbeitung der Regesta Imperii e.V. [01/06] Suda On Line Byzantine Lexicography [01/06

  20. Exploring Young Children's Performance on and Acceptance of an Educational Scenario-Based Digital Game for Teaching Route-Planning Strategies: A Case Study

    Science.gov (United States)

    Lin, Yi-Hui; Hou, Huei-Tse

    2016-01-01

    Researchers suggest that game-based learning (GBL) can be used to facilitate mathematics learning. However, empirical GBL research that targets young children is still limited. The purposes of the study is to develop a scenario-based digital game to promote children's route-planning ability, to empirically explore children's learning performance…

  1. Exploring Young Children's Performance on and Acceptance of an Educational Scenario-Based Digital Game for Teaching Route-Planning Strategies: A Case Study

    Science.gov (United States)

    Lin, Yi-Hui; Hou, Huei-Tse

    2016-01-01

    Researchers suggest that game-based learning (GBL) can be used to facilitate mathematics learning. However, empirical GBL research that targets young children is still limited. The purposes of the study is to develop a scenario-based digital game to promote children's route-planning ability, to empirically explore children's learning performance…

  2. The Visual Aural Digit Span Test for Seventh Graders: A Normative Study. The Bender Gestalt and VADS Test Performance of Learning Disabled Middle School Pupils.

    Science.gov (United States)

    Koppitz, Elizabeth M.

    1981-01-01

    The Visual Aural Digit Span Test (VADS Test), developed and standardized as a diagnostic test for learning disabilities in kindergarten to sixth grade, was adopted for use with seventh graders. An investigation of the relationship between the VADS Test scores and reading achievement showed the validity of the test for middle school pupils. (Author)

  3. Becoming digital

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2015-01-01

    . Originality/value: The study contributes to ethnographic research in public administration by combining two separate subfields, e-government and street-level bureaucracy, to discern recent transformations in public service delivery. In the digital era, tasks, control and equality are distributed in ways...... that call for symmetrical and relational approaches to studying street-level bureaucracy. The argument goes beyond technological or social determinism to find a fruitful intermediary position pointing at technological change as having both constraining and enabling effects....

  4. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    Artiklen præsenterer først nogle generelle problemstillinger omkring Digital Humanities (DH) med det formål at undersøge dem nærmere i relation til konkrete eksempler på forskellige digitaliseringsmåder og ændringer i dokumentproduktion. I en nærmere afgrænsning vælger artiklen den tendens i DH...

  5. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    Artiklen præsenterer først nogle generelle problemstillinger omkring Digital Humanities (DH) med det formål at undersøge dem nærmere i relation til konkrete eksempler på forskellige digitaliseringsmåder og ændringer i dokumentproduktion. I en nærmere afgrænsning vælger artiklen den tendens i DH...

  6. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J M

    2010-01-01

    The design of an analog-to-digital converter or digital-to-analog converter is one of the most fascinating tasks in micro-electronics. In a converter the analog world with all its intricacies meets the realm of the formal digital abstraction. Both disciplines must be understood for an optimum conversion solution. In a converter also system challenges meet technology opportunities. Modern systems rely on analog-to-digital converters as an essential part of the complex chain to access the physical world. And processors need the ultimate performance of digital-to-analog converters to present the results of their complex algorithms. The same progress in CMOS technology that enables these VLSI digital systems creates new challenges for analog-to-digital converters: lower signal swings, less power and variability issues. Last but not least, the analog-to-digital converter must follow the cost reduction trend. These changing boundary conditions require micro-electronics engineers to consider their design choices for...

  7. High Performance Computing and Digital Media Technology Experiment Teaching Platform Construction Research%高性能计算与数字媒体技术实验教学平台建设初探

    Institute of Scientific and Technical Information of China (English)

    何志州; 爨莹

    2013-01-01

    Establish high performance computing and digital media technology can be traditional experimental teaching platform for the digital media teaching and high-end Virtual Reality technology (insgroupsto Reality, abbreviation VR) organically, the comprehensive resource, equipment resources sharing, and on the basis of the new century, film and television animation around China and computer games and digital media technology for professional design and production talented person's demand, and oil exploration and development fields information visualization and multimedia digital technology combining the pressing re-quirement, in order to perfect, supporting digital media professional each professional basic course of experiment teaching as a starting point, optimize experiment teaching structure, improve the teaching level and students' innovative ability.%建立高性能计算与数字媒体技术实验教学平台可将传统的数字媒体教学与高端虚拟现实技术(Virtual Reality,简称VR)有机地结合,在综合资源、设备资源共享的基础上,围绕新世纪我国动画、影视和计算机游戏等数字媒体技术对专业设计制作人才的需求,以及石油勘探开发领域信息可视化与多媒体数字技术相结合的迫切要求,以完善、配套数字媒体专业各门专业基础课的实验教学为出发点,优化实验教学结构,提高教学水平和学生创新动手能力。

  8. Digital citizens Digital nations: the next agenda

    NARCIS (Netherlands)

    A.W. (Bert) Mulder; M.W. (Martijn) Hartog

    2015-01-01

    DIGITAL CITIZENS CREATE A DIGITAL NATION Citizens will play the lead role as they – in the next phase of the information society – collectively create a digital nation. Personal adoption of information and communication technology will create a digital infrastructure that supports individual and

  9. Digital citizens Digital nations: the next agenda

    NARCIS (Netherlands)

    Mulder, A.W. (Bert); Hartog, M.W. (Martijn)

    2015-01-01

    DIGITAL CITIZENS CREATE A DIGITAL NATION Citizens will play the lead role as they – in the next phase of the information society – collectively create a digital nation. Personal adoption of information and communication technology will create a digital infrastructure that supports individual and col

  10. Digital microarray analysis for digital artifact genomics

    Science.gov (United States)

    Jaenisch, Holger; Handley, James; Williams, Deborah

    2013-06-01

    We implement a Spatial Voting (SV) based analogy of microarray analysis for digital gene marker identification in malware code sections. We examine a famous set of malware formally analyzed by Mandiant and code named Advanced Persistent Threat (APT1). APT1 is a Chinese organization formed with specific intent to infiltrate and exploit US resources. Manidant provided a detailed behavior and sting analysis report for the 288 malware samples available. We performed an independent analysis using a new alternative to the traditional dynamic analysis and static analysis we call Spatial Analysis (SA). We perform unsupervised SA on the APT1 originating malware code sections and report our findings. We also show the results of SA performed on some members of the families associated by Manidant. We conclude that SV based SA is a practical fast alternative to dynamics analysis and static analysis.

  11. All digital pulsewidth control loop

    Science.gov (United States)

    Huang, Hong-Yi; Jan, Shiun-Dian; Pu, Ruei-Iun

    2013-03-01

    This work presents an all-digital pulsewidth control loop (ADPWCL). The proposed system accepts a wide range of input duty cycles and performs a fast correction to the target output pulsewidth. An all-digital delay-locked loop (DLL) with fast locking time using a simplified time to digital converter and a new differential two-step delay element is proposed. The area of the delay element is much smaller than that in conventional designs, while having the same delay range. A test chip is verified in a 0.18-µm CMOS process. The measured duty cycle ranges from 4% to 98% with 7-bit resolution.

  12. Digital Demodulator For Advanced Receiver

    Science.gov (United States)

    Sadr, Ramin; Hurd, William J.

    1990-01-01

    Complexity and cost reduced by new design for half-band filters. Digital demodulator designed for use in reception of phase- and amplitude-modulated digital signals of bandwidths up to 15 MHz on microwave carriers. System performs coherent demodulation in phase and in quadrature with carrier locked in phase to intermediate frequency of 10 MHz. Design suitable for fabrication in very-large-scale integrated circuitry. Principal innovative feature of demodulator is design of half-band digital low-pass filters that remove sum-frequency components.

  13. CCD digital radiography system

    Science.gov (United States)

    Wang, Yi; Kang, Xi; Li, Yuanjing; Cheng, Jianping; Hou, Yafei; Han, Haiwei

    2009-07-01

    Amorphous silicon flat-panel detector is the mainstream used in digital radiography (DR) system. In latest years, scintillation screen coupled with CCD DR is becoming more popular in hospital. Compared with traditional amorphous silicon DR, CCD-DR has better spatial resolution and has little radiation damage. It is inexpensive and can be operated easily. In this paper, A kind of CCD based DR system is developed. We describe the construction of the system, the system performances and experiment results.

  14. Digital Content Strategies

    OpenAIRE

    Daniel Halbheer; Florian Stahl; Oded Koenigsberg; Lehmann, Donald R

    2013-01-01

    This paper studies content strategies for online publishers of digital information goods. It examines sampling strategies and compares their performance to paid content and free content strategies. A sampling strategy, where some of the content is offered for free and consumers are charged for access to the rest, is known as a "metered model" in the newspaper industry. We analyze optimal decisions concerning the size of the sample and the price of the paid content when sampling serves the dua...

  15. Digital processing system for developing countries

    Science.gov (United States)

    Nanayakkara, C.; Wagner, H.

    1977-01-01

    An effort was undertaken to perform simple digital processing tasks using pre-existing general purpose digital computers. An experimental software package, LIGMALS, was obtained and modified for this purpose. The resulting software permits basic processing tasks to be performed including level slicing, gray mapping and ratio processing. The experience gained in this project indicates a possible direction which may be used by other developing countries to obtain digital processing capabilities.

  16. A low-power high-performance configurable auto-gain control loop for a digital hearing aid SoC

    Science.gov (United States)

    Chengying, Chen; Hainan, Liu; Yong, Hei; Jun, Fan; Xiaoyu, Hu

    2013-10-01

    A low-power, configurable auto-gain control loop for a digital hearing aid system on a chip (SoC) is presented. By adopting a mixed-signal feedback control structure and peak detection and judgment, it can work in automatic gain or variable gain control modes through a digital signal processing unit. A noise-reduction and dynamic range (DR) improvement technique is also used to ensure the DR of the circuit in a low-voltage supply. The circuit is implemented in an SMIC 0.13 μm 1P8M CMOS process. The measurement results show that in a 1 V power supply, 1.6 kHz input frequency and 200 mVp—p, the SFDR is 74.3 dB, the THD is 66.1 dB, and the total power is 89 μW, meeting the application requirements of hearing aid SoCs.

  17. Digital pathology

    CERN Document Server

    Sucaet, Yves

    2014-01-01

    Digital pathology has experienced exponential growth, in terms of its technology and applications, since its inception just over a decade ago. Though it has yet to be approved for primary diagnostics, its values as a teaching tool, facilitator of second opinions and quality assurance reviews and research are becoming, if not already, undeniable. It also offers the hope of providing pathology consultant and educational services to under-served areas, including regions of the world that could not possibly sustain this level of services otherwise. And this is just the beginning, as its adoption b

  18. Focus: Digital

    DEFF Research Database (Denmark)

    Technology has been an all-important and defining element within the arts throughout the 20th century, and it has fundamentally changed the ways in which we produce and consume music. With this Focus we investigate the latest developments in the digital domain – and their pervasiveness and rapid...... production and reception of contemporary music and sound art. With ‘Digital’ we present four composers' very different answers to how technology impact their work. To Juliana Hodkinson it has become an integral part of her sonic writing. Rudiger Meyer analyses the relationships between art and design and how...

  19. Cost Model for Digital Curation: Cost of Digital Migration

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

    2009-01-01

    activities by analysing the OAIS Model, and supplemented this analysis with findings from other models, literature and own experience. To verify the model it has been tested on two sets of data from a normalisation project and a migration project at the Danish National Archives. The study found that the OAIS...... for digital preservation and to increase cost effectiveness of digital preservation activities. In this study we describe an activity based costing methodology for digital preservation based on the OAIS Reference Model. In order to estimate the cost of digital migrations we have identified cost critical...... model provides a sound overall framework for cost breakdown, but that some functions, especially when it comes to performing and evaluating the actual migration, need additional detailing in order to cost activities accurately....

  20. Design Thinking for Digital Fabrication in Education

    DEFF Research Database (Denmark)

    Smith, Rachel Charlotte; Iversen, Ole Sejer; Hjorth, Mikkel

    2015-01-01

    In this paper, we argue that digital fabrication in education may benefit from design thinking, to foster a more profound understanding of digital fabrication processes among students. Two related studies of digital fabrication in education are presented in the paper. In an observational study we...... found that students (eleven to fifteen) lacked an understanding of the complexity of the digital fabrication process impeding on the potentials of digital fabrication in education. In a second explorative research through design study, we investigated how a focus on design thinking affected the students......’ performance in digital fabrication processes. Our findings indicate that design thinking can provide students with a general understanding of the creative and complex process through which artifacts and futures emerge in processes of digital fabrication....

  1. Digital Light Processing and MEMS: reflecting the digital display needs of the networked society

    Science.gov (United States)

    Hornbeck, Larry J.

    1996-08-01

    Digital video technology is becoming increasingly important to the networked society. The natural interface to digital video is a digital display, one that accepts electrical bits at its input and converts them into optical bits at the output. The digital-to-analog processing function is performed in the mind of the observer. Texas Instruments has developed such a display with its recent market introduction of the Digital Light ProcessingTM (DLPTM) projection display. DLP technology is based on the Digital Micromirror DeviceTM (DMDTM), a microelectromechanical systems (MEMS) array of semiconductor-based digital light switches. The DMD switching array precisely controls a light source for projection display and digital printing applications. This paper presents an overview of DLP technology along with the architecture, projection operation, manufacture, and reliability of the DMD. Features of DMD technology that distinguish it from conventional MEMS technology are explored. Finally, the paper provides a view of DLP business opportunities.

  2. Design and implementation of high performance digital receiver based on FPGA%高性能数字接收机FPGA设计与实现

    Institute of Scientific and Technical Information of China (English)

    张黎明

    2013-01-01

    A digital receiver widely applied in multi-mode comprehensive test instrument was designed to meet the need of test of multi-mode radio communication.According to Band-pass-sampling theory,the Intermediate Frequency (IF) signals of QPSK/TD-SCDMA etc.were directly sampled at 153.6 MHz.The digital-down-converter (DDC),shift-phase-filter (SPF),multi-rate-decimating (MRD),shaping-filter (SF) and symbol-synchronization (SS) were implemented in field-programmable gate array(FPGA) so that digital signal processor(DSP) made algorithm-demodulation with quadrature IQ signal.The experiment result shows that the solution can reduce resource consume in DDC,enhance dynamic-linear-range of receive-channel,increase Effective-Number of Bits (ENOB) and improve vector-demodulation,so that it is suitable for digital receiver with multi-mode and wide-band.%针对多模移动通信标准测试的需求,设计一款可广泛应用于多模综测仪的数字接收机.根据带通采样原理直接对153.6 MHz的QPSK/TD-SCDMA等中频信号进行采样,在FPGA中实现高效数字下变频、移相滤波、多速率抽取、成型滤波和符号同步等功能,以正交I、Q信号输出便于后续DSP对其进行软件算法解调和处理.实验结果表明,该方案能有效减少数字下变频资源消耗、增强接收通道的线性动态范围、提高模数转换器的有效分辨率、改善通道矢量解调指标,适合作为多模宽带数字中频接收机的实施方案.

  3. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    overgangen fra trykkekultur til digital kultur. For det første problemstillingen omkring digitalisering af litterær kulturarv med fokus på kodning og tagging af teksten samt organisering i hypertekststrukturer. For det andet reorganiseringen af det digitale dokument i dataelementer og database. For det......, der betragter DH som forbundet med "making" og "building" af digitale objekter og former. Dette kan også karakteriseres som DH som praktisk-produktiv vending. Artiklen har valgt tre typer af digitalisering. De er valgt ud fra, at de skal repræsentere forskellige måder at håndtere digitaliseringen på...... og forskellige versioner af den praktisk-produktive vending. Artiklen undersøger tre typer digitalisering fra 1990erne til i dag ud fra denne optik. De repræsenterer forskellige former for approach til digitalisering og det digitale dokument og afspejler forskellige typer af problemstillinger i...

  4. Digital Avionics

    Science.gov (United States)

    Koelbl, Terry G.; Ponchak, Denise; Lamarche, Teresa

    2003-01-01

    Digital Avionics activities played an important role in the advancements made in civil aviation, military systems, and space applications. This document profiles advances made in each of these areas by the aerospace industry, NASA centers, and the U.S. military. Emerging communication technologies covered in this document include Internet connectivity onboard aircraft, wireless broadband communication for aircraft, and a mobile router for aircraft to communicate in multiple communication networks over the course of a flight. Military technologies covered in this document include avionics for unmanned combat air vehicles and microsatellites, and head-up displays. Other technologies covered in this document include an electronic flight bag for the Boeing 777, and surveillance systems for managing airport operations.

  5. Structural Design and Performance Simulation of Digital Water Hydraulic Relief Valve%数字式纯水溢流阀的结构设计与性能仿真分析

    Institute of Scientific and Technical Information of China (English)

    颜凌云; 武鹏飞; 包宗贤; 李红星

    2013-01-01

    This article describes the digital water hydraulic relief valve by self-designed, And through the Matlab/Simulink software simulation the static and dynamic performance of the relief valve, Then the simulation results verify the correctness of the design theory.%该文介绍了自行设计的数字式纯水液压溢流阀,并通过Matlab/Simulink软件对溢流阀的静动态性能进行了仿真分析,由仿真结果验证了设计理论的正确性.

  6. Digital work in a digitally challenged organization

    NARCIS (Netherlands)

    Davison, R.M.; Ou, Carol

    2016-01-01

    Digitally literate employees are accustomed to having free access to digital media technologies. However, some organizations enact information technology (IT) governance structures that explicitly proscribe access to these technologies, resulting in considerable tension between employees and the org

  7. Digital work in a digitally challenged organization

    NARCIS (Netherlands)

    Davison, R.M.; Ou, Carol

    Digitally literate employees are accustomed to having free access to digital media technologies. However, some organizations enact information technology (IT) governance structures that explicitly proscribe access to these technologies, resulting in considerable tension between employees and the

  8. USNA DIGITAL FORENSICS LAB

    Data.gov (United States)

    Federal Laboratory Consortium — To enable Digital Forensics and Computer Security research and educational opportunities across majors and departments. Lab MissionEstablish and maintain a Digital...

  9. USNA DIGITAL FORENSICS LAB

    Data.gov (United States)

    Federal Laboratory Consortium — To enable Digital Forensics and Computer Security research and educational opportunities across majors and departments. Lab Mission Establish and maintain a Digital...

  10. Digital Student Expertise in the Making

    DEFF Research Database (Denmark)

    Stenbøg, Sofie

    student (e.g. Bennett et. al. 2008, Helsper & Eynon 2009). In this paper I go beyond the idea of digital expertise as something intrinsic. Building on STS’s central notion of performativity (e.g. Law & Singleton 2000) the paper argues that digital expertise should be studied as a temporary achievement......’ digital competencies as much as possible in teaching. The paper concludes that understanding digital student expertise as a performative and collec-tive effort, rather than something given will have implications for digital school management....... all around the world and their entry has not escaped the attention from teachers, school managers and policy makers. A current trend within education management, in Denmark as well as internationally, is to incorporate the students’ digital skills or ‘expertise’ as a resource in teaching, e.g. through...

  11. Digital Marketer: Facing Digital Marketing Opportunities

    OpenAIRE

    NEGRICEA, Costel Iliuta; PURCAREA, Ioan Matei

    2015-01-01

    We are witnessing the emergence of new ecosystems thanks to digital disruption, marketers being challenged to bring marketing operations into the digital era, enhance the customer journey and shift consumer behavior with the help of the digital tools, while actively encouraging feedback from users, and building a circle of trust with the company’s audience. Recent findings showed clear differences of consumers’ preferences and of what marketers say they’re doing with digital technology. Respo...

  12. Can We Teach Digital Natives Digital Literacy?

    Science.gov (United States)

    Ng, Wan

    2012-01-01

    In recent years, there has been much debate about the concept of digital natives, in particular the differences between the digital natives' knowledge and adoption of digital technologies in informal versus formal educational contexts. This paper investigates the knowledge about educational technologies of a group of undergraduate students…

  13. Digital Imaging and Screening for Diabetic Retinopathy

    OpenAIRE

    Hull, C.

    2008-01-01

    The National Screening Committee has stated that “All people with diabetes aged 12 years and older should be offered screening for sight-threatening diabetic retinopathy using digital photography.”1 Digital imaging offers several advantages such as archiving, ease of viewing evidence of progression, quality assurance, patient education and immediate indication of ungradable images. Knowledge of key aspects of digital imaging technology and performance therefore underpin screening for diabetic...

  14. Digital compositing in the VFX pipeline

    OpenAIRE

    Ostasheva, Alexandra

    2015-01-01

    The purpose of this thesis is to explore a specific area of visual effects production - Digital Compositing. The work explains the origin of this craft and clarifies reasons for its demand in the field. The theoretical section explains the role of Digital Compositing in the VFX pipeline, as well as introduces a reader to the major compositing operations, which digital artists in the field have to be able to perform. Among those are compositing CGI materials into live-action plates, rotosc...

  15. Define Digital Vernacular

    Institute of Scientific and Technical Information of China (English)

    刘佳; 李海英; James Stevens; Rough Nelson

    2014-01-01

    As science and technology developed, the tools of humans developed from humans’hands, to mechanical and digital technologies. The tools influ-ence almost everything in the humans’world, so does vernacular. The digital vernacular could be understood as using digital technology to vernacular; the digital means technologies. It also could be understood as doing vernacular in a digital way;the digital means data and information, in other words it can be seeking truth from facts. Define digital vernacular is not only what is digital vernacular, but also about how to do the digital vernacular and what kind of attitude we should hold to-ward the digital vernacular. Define digital vernacular as both thinking and doing.

  16. Evolving digital ecological networks.

    Science.gov (United States)

    Fortuna, Miguel A; Zaman, Luis; Wagner, Aaron P; Ofria, Charles

    2013-01-01

    "It is hard to realize that the living world as we know it is just one among many possibilities" [1]. Evolving digital ecological networks are webs of interacting, self-replicating, and evolving computer programs (i.e., digital organisms) that experience the same major ecological interactions as biological organisms (e.g., competition, predation, parasitism, and mutualism). Despite being computational, these programs evolve quickly in an open-ended way, and starting from only one or two ancestral organisms, the formation of ecological networks can be observed in real-time by tracking interactions between the constantly evolving organism phenotypes. These phenotypes may be defined by combinations of logical computations (hereafter tasks) that digital organisms perform and by expressed behaviors that have evolved. The types and outcomes of interactions between phenotypes are determined by task overlap for logic-defined phenotypes and by responses to encounters in the case of behavioral phenotypes. Biologists use these evolving networks to study active and fundamental topics within evolutionary ecology (e.g., the extent to which the architecture of multispecies networks shape coevolutionary outcomes, and the processes involved).

  17. Evolving digital ecological networks.

    Directory of Open Access Journals (Sweden)

    Miguel A Fortuna

    Full Text Available "It is hard to realize that the living world as we know it is just one among many possibilities" [1]. Evolving digital ecological networks are webs of interacting, self-replicating, and evolving computer programs (i.e., digital organisms that experience the same major ecological interactions as biological organisms (e.g., competition, predation, parasitism, and mutualism. Despite being computational, these programs evolve quickly in an open-ended way, and starting from only one or two ancestral organisms, the formation of ecological networks can be observed in real-time by tracking interactions between the constantly evolving organism phenotypes. These phenotypes may be defined by combinations of logical computations (hereafter tasks that digital organisms perform and by expressed behaviors that have evolved. The types and outcomes of interactions between phenotypes are determined by task overlap for logic-defined phenotypes and by responses to encounters in the case of behavioral phenotypes. Biologists use these evolving networks to study active and fundamental topics within evolutionary ecology (e.g., the extent to which the architecture of multispecies networks shape coevolutionary outcomes, and the processes involved.

  18. Optimization Design for Digital Binoculars

    Institute of Scientific and Technical Information of China (English)

    CEN Jun-bo; CHEN Wei-min; LI Hui; HUANG Shang-lian

    2005-01-01

    In order to develop competitive and high performance/cost ratio of digital binoculars, design scheme should be optimized in term of technical capacity, economic benefit, product performance, risk management, etc. The common optimization method is limited in qualitative analysis, and the parameter optimization method is limited in obtaining optimal parameter only from technical side. Each method has its limitation. Based on the analysis of digital binoculars parameters, optional design schemes are laid down.Analytic hierarchy process combined the qualitative analysis with the quantitative analysis together. The design schemes are optimized, and result is worked out.

  19. Digital forensics digital evidence in criminal investigations

    CERN Document Server

    Marshall, Angus McKenzie

    2009-01-01

    The vast majority of modern criminal investigations involve some element of digital evidence, from mobile phones, computers, CCTV and other devices. Digital Forensics: Digital Evidence in Criminal Investigations provides the reader with a better understanding of how digital evidence complements "traditional" scientific evidence and examines how it can be used more effectively and efficiently in a range of investigations. Taking a new approach to the topic, this book presents digital evidence as an adjunct to other types of evidence and discusses how it can be deployed effectively in s

  20. Digital dannelse

    DEFF Research Database (Denmark)

    Bundsgaard, Jeppe

    2012-01-01

    I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et dannelsesspørgs......I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et...... dannelsesspørgsmål knyttet til it. Hvad er egentlig digital dannelse? Og hvad betyder det for danskfaget?...

  1. Digital platforms as enablers for digital transformation

    DEFF Research Database (Denmark)

    Hossain, Mokter; Lassen, Astrid Heidemann

    2017-01-01

    Digital platforms offer new ways for organizations to collaborate with the external environment for ideas, technologies, and knowledge. They provide new possibilities and competence but they also bring new challenges for organizations. Understanding the role of these platforms in digital...... transformation is crucial. This study aims at exploring how organizations are driven towards transformation in various ways to embrace digital platforms for ideas, technologies, and knowledge. It shows the opportunities and challenges digital platforms bring in organizations. It also highlights underlying...... mechanisms and potential outcomes of various digital platforms. The contribution of the submission is valuable for scholars to understand and further explore this area. It provides insight for practitioners to capture value through digital platforms and accelerate the pace of organizations’ digital...

  2. H. Sapiens Digital: From Digital Immigrants and Digital Natives to Digital Wisdom

    Science.gov (United States)

    Prensky, Marc

    2009-01-01

    As we move further into the 21st century, the digital native/digital immigrant paradigm created by Marc Prensky in 2001 is becoming less relevant. In this article, Prensky suggests that we should focus instead on the development of what he calls "digital wisdom." Arguing that digital technology can make us not just smarter but truly wiser, Prensky…

  3. Land Treatment Digital Library

    Science.gov (United States)

    Pilliod, David S.; Welty, Justin L.

    2013-01-01

    The Land Treatment Digital Library (LTDL) was created by the U.S. Geological Survey to catalog legacy land treatment information on Bureau of Land Management lands in the western United States. The LTDL can be used by federal managers and scientists for compiling information for data-calls, producing maps, generating reports, and conducting analyses at varying spatial and temporal scales. The LTDL currently houses thousands of treatments from BLM lands across 10 states. Users can browse a map to find information on individual treatments, perform more complex queries to identify a set of treatments, and view graphs of treatment summary statistics.

  4. Analog-Digital Interfaces

    Science.gov (United States)

    Keller, Matthias; Murmann, Boris; Manoli, Yiannos

    This chapter discusses trends in the area of low-power, high-performance A/D conversion. Survey data collected over the past thirteen years are examined to show that the conversion energy of ADCs has halved every two years while the speed-resolution product has doubled approximately only every four years. A closer inspection on the impact of technology scaling and developments in ADC design are then presented to explain the observed trends. Next, opportunities in minimalistic and digitally assisted design are reviewed for the most popular converter architectures. Finally, trends in Delta-Sigma ADCs are analyzed in detail.

  5. Monitoring the Digital Divide

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, Les

    2003-05-28

    It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work.

  6. Enabling Digital Literacy

    DEFF Research Database (Denmark)

    Ryberg, Thomas; Georgsen, Marianne

    2010-01-01

    There are some tensions between high-level policy definitions of “digital literacy” and actual teaching practice. We need to find workable definitions of digital literacy; obtain a better understanding of what digital literacy might look like in practice; and identify pedagogical approaches, which......, these operate on a meso-level mediating between high-level concepts of digital literacy and classroom practice....... support teachers in designing digital literacy learning. We suggest that frameworks such as Problem Based Learning (PBL) are approaches that enable digital literacy learning because they provide good settings for engaging with digital literacy. We illustrate this through analysis of a case. Furthermore...

  7. Digital Image Compression Using Artificial Neural Networks

    Science.gov (United States)

    Serra-Ricart, M.; Garrido, L.; Gaitan, V.; Aloy, A.

    1993-01-01

    The problem of storing, transmitting, and manipulating digital images is considered. Because of the file sizes involved, large amounts of digitized image information are becoming common in modern projects. Our goal is to described an image compression transform coder based on artificial neural networks techniques (NNCTC). A comparison of the compression results obtained from digital astronomical images by the NNCTC and the method used in the compression of the digitized sky survey from the Space Telescope Science Institute based on the H-transform is performed in order to assess the reliability of the NNCTC.

  8. Multi-digital Still Cameras with CCD

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-jing; LONG Zai-chuan; XIONG Ping; HUAN Yao-xiong

    2006-01-01

    Digital still camera is a completely typical tool for capturing the digital images. With the development of IC technology and optimization-algorithm, the performance of digital still cameras(DSCs) will be more and more powerful in the world. But can we obtain the more and better info using the combined information from the multi-digital still camera? The answer is yes by some experiments. By using multi-DSC at different angles, the various 3-D informations of the object are obtained.

  9. Examining Factors Predicting Students’ Digital Competence

    Directory of Open Access Journals (Sweden)

    Ove Edvard Hatlevik

    2015-02-01

    Full Text Available The purpose of this study was to examine factors predicting lower secondary school students’ digital competence and to explore differences between students when it comes to digital competence. Results from a digital competence test and survey in lower secondary school will be presented. It is important to learn more about and investigate what characterizes students’ digital competence. A sample of 852 ninth-grade Norwegian students from 38 schools participated in the study. The students answered a 26 item multiple-choice digital competence test and a self-report questionnaire about family background, motivation, and previous grades. Structural equation modeling was used to test a model of the hypothesised relationship between family background, mastery orientation, previous achievements, and digital competence. The results indicate variation in digital competence among the ninth-graders. Further, analyses showed that students’ conditions at home, i.e., language integration and cultural capital, together with mastery orientation and academic achievements predict students digital competence. This study indicates that that there is evidence of digital diversity between lower secondary students. It does not seem like the development of digital competence among the students happens automatically. Students’ family background and school performance are the most important factors. Therefore, as this study shows, it is necessary to further investigate how schools can identify students’ level of competence and to develop plans and actions for how schools can help to try to equalize differences.

  10. Digital Literacy and New Technological Perspectives

    Science.gov (United States)

    Feola, Elvia Ilaria

    2016-01-01

    This paper aims to reflect on the implications and challenges that experts in the field have to deal with when you want to evaluate the performance in the use of digital technologies in teaching. The argument stems from a contextual and social assessment, and then proceeds to an application and methodological connotation of digital literacy…

  11. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  12. Digital signal processing: Handbook

    Science.gov (United States)

    Goldenberg, L. M.; Matiushkin, B. D.; Poliak, M. N.

    The fundamentals of the theory and design of systems and devices for the digital processing of signals are presented. Particular attention is given to algorithmic methods of synthesis and digital processing equipment in communication systems (e.g., selective digital filtering, spectral analysis, and variation of the signal discretization frequency). Programs for the computer-aided analysis of digital filters are described. Computational examples are presented, along with tables of transfer function coefficients for recursive and nonrecursive digital filters.

  13. Digital preservation for heritages

    CERN Document Server

    Lu, Dongming

    2011-01-01

    ""Digital Preservation for Heritages: Technologies and Applications"" provides a comprehensive and up-to-date coverage of digital technologies in the area of cultural heritage preservation, including digitalization, research aiding, conservation aiding, digital exhibition, and digital utilization. Processes, technical frameworks, key technologies, as well as typical systems and applications are discussed in the book. It is intended for researchers and students in the fields of computer science and technology, museology, and archaeology. Dr. Dongming Lu is a professor at College of Computer Sci

  14. Characteristics of Digital Sustainability

    OpenAIRE

    Stuermer, Matthias

    2014-01-01

    The concept of digital sustainability is mentioned in research on digital preservation as well as on openness topics. Both streams of literature point out the necessary discussion how to create, use, and regulate digital resources in order to maximize their value for our society today and in the future. This paper therefore reviews current work on digital sustainability, presents a list of six charac-teristics how to define digitally sustainable goods, and draws the link to aspects of e-gover...

  15. Digital breast tomosynthesis for detecting multifocal and multicentric breast cancer: influence of acquisition geometry on model observer performance in breast phantom images

    Science.gov (United States)

    Wen, Gezheng; Park, Subok; Markey, Mia K.

    2017-03-01

    Multifocal and multicentric breast cancer (MFMC), i.e., the presence of two or more tumor foci within the same breast, has an immense clinical impact on treatment planning and survival outcomes. Detecting multiple breast tumors is challenging as MFMC breast cancer is relatively uncommon, and human observers do not know the number or locations of tumors a priori. Digital breast tomosynthesis (DBT), in which an x-ray beam sweeps over a limited angular range across the breast, has the potential to improve the detection of multiple tumors.1, 2 However, prior efforts to optimize DBT image quality only considered unifocal breast cancers (e.g.,3-9), so the recommended geometries may not necessarily yield images that are informative for the task of detecting MFMC. Hence, the goal of this study is to employ a 3D multi-lesion (ml) channelized-Hotelling observer (CHO) to identify optimal DBT acquisition geometries for MFMC. Digital breast phantoms and simulated DBT scanners of different geometries (e.g., wide or narrow arc scans, different number of projections in each scan) were used to generate image data for the simulation study. Multiple 3D synthetic lesions were inserted into different breast regions to simulate MF cases and MC cases. 3D partial least squares (PLS) channels, and 3D Laguerre-Gauss (LG) channels were estimated to capture discriminant information and correlations among signals in locally varying anatomical backgrounds, enabling the model observer to make both image-level and location-specific detection decisions. The 3D ml-CHO with PLS channels outperformed that with LG channels in this study. The simulated MC cases and MC cases were not equally difficult for the ml-CHO to detect across the different simulated DBT geometries considered in this analysis. Also, the results suggest that the optimal design of DBT may vary as the task of clinical interest changes, e.g., a geometry that is better for finding at least one lesion may be worse for counting the

  16. 微镜阵列激光成像技术及其性能分析%Laser imaging based on digital micromirror device and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    邓正芳; 苏金善; 杨兴雨; 张冬冬

    2015-01-01

    提出了一种激光三维成像技术,该方法以推扫方式工作,采用数字微镜器件(DigitalMirror Device,DMD)来进行激光回波脉冲飞行时间(Time of Flight,TOF)的空间转换.由于目标上不同距离点回波脉冲的飞行时间不同,当脉冲到达时微透镜阵列将从一个状态转换到另一个状态,在接收端传感器焦平面上显示不同相对位置的条纹,利用条纹相对距离可以重建目标的剖面轮廓距离像.相比于其他三维成像技术,该技术具有成像速率高、探测视场角大、结构简单、体积小易于集成化等优点.

  17. Cognitive Hacking and Digital Government: Digital Identity

    OpenAIRE

    Paul Thompson

    2004-01-01

    Recently the National Center for Digital Government held a workshop on "The Virtual Citizen: Identity, Autonomy, and Accountability: A Civic Scenario Exploration of the Role of Identity in On-Line. Discussions at the workshop focused on five scenarios for future authentication policies with respect to digital identity. The underlying technologies considered for authentication were: biometrics: cryptography, with a focus on digital signatures; secure processing/computation; and reputation syst...

  18. Digital Archive Policies and Trusted Digital Repositories

    Directory of Open Access Journals (Sweden)

    MacKenzie Smith

    2007-07-01

    Full Text Available The MIT Libraries, the San Diego Supercomputer Center, and the University of California San Diego Libraries are conducting the PLEDGE Project to determine the set of policies that affect operational digital preservation archives and to develop standardized means of recording and enforcing them using rules engines. This has the potential to allow for automated assessment of “trustworthiness” of digital preservation archives. We are also evaluating the completeness of other efforts to define policies for digital preservation such as the RLG/NARA Trusted Digital Repository checklist and the PREMIS metadata schema. We present our results to date.

  19. DESDynI Quad First Stage Processor - A Four Channel Digitizer and Digital Beam Forming Processor

    Science.gov (United States)

    Chuang, Chung-Lun; Shaffer, Scott; Smythe, Robert; Niamsuwan, Noppasin; Li, Samuel; Liao, Eric; Lim, Chester; Morfopolous, Arin; Veilleux, Louise

    2013-01-01

    The proposed Deformation, Eco-Systems, and Dynamics of Ice Radar (DESDynI-R) L-band SAR instrument employs multiple digital channels to optimize resolution while keeping a large swath on a single pass. High-speed digitization with very fine synchronization and digital beam forming are necessary in order to facilitate this new technique. The Quad First Stage Processor (qFSP) was developed to achieve both the processing performance as well as the digitizing fidelity in order to accomplish this sweeping SAR technique. The qFSP utilizes high precision and high-speed analog to digital converters (ADCs), each with a finely adjustable clock distribution network to digitize the channels at the fidelity necessary to allow for digital beam forming. The Xilinx produced FX130T Virtex 5 part handles the processing to digitally calibrate each channel as well as filter and beam form the receive signals. Demonstrating the digital processing required for digital beam forming and digital calibration is instrumental to the viability of the proposed DESDynI instrument. The qFSP development brings this implementation to Technology Readiness Level (TRL) 6. This paper will detail the design and development of the prototype qFSP as well as the preliminary results from hardware tests.

  20. Digitizing radiographic films: a simple way to evaluate indirect digital images

    Directory of Open Access Journals (Sweden)

    Izabel Regina Fischer Rubia-Bullen

    2007-02-01

    Full Text Available OBJECTIVES: This study applied a simple method to evaluate the performance of three digital devices (two scanners and one digital camera using the reproducibility of pixel values attributed to the same radiographic image. METHODS: Using the same capture parameters, a radiographic image was repeatedly digitized in order to determine the variability of pixel values given to the image throughout the digitization process. One coefficient value was obtained and was called pixel value reproducibility. RESULTS: A significant difference in pixel values was observed among the three devices for the digitized images (ANOVA, p<0.00001. There was significant pixel value variability at the same digitization conditions for one scanner and the digital camera. CONCLUSIONS: Digital devices may assign pixel values differently in consecutive digitization depending on the optical density of the radiographic image and the equipment. The pixel value reproducibility was not satisfactory as tested for two devices. It is maybe advisable knowing the digitization variations regarding pixel values whenever using digital radiography images in longitudinal clinical examinations.

  1. DESDynI Quad First Stage Processor - A Four Channel Digitizer and Digital Beam Forming Processor

    Science.gov (United States)

    Chuang, Chung-Lun; Shaffer, Scott; Smythe, Robert; Niamsuwan, Noppasin; Li, Samuel; Liao, Eric; Lim, Chester; Morfopolous, Arin; Veilleux, Louise

    2013-01-01

    The proposed Deformation, Eco-Systems, and Dynamics of Ice Radar (DESDynI-R) L-band SAR instrument employs multiple digital channels to optimize resolution while keeping a large swath on a single pass. High-speed digitization with very fine synchronization and digital beam forming are necessary in order to facilitate this new technique. The Quad First Stage Processor (qFSP) was developed to achieve both the processing performance as well as the digitizing fidelity in order to accomplish this sweeping SAR technique. The qFSP utilizes high precision and high-speed analog to digital converters (ADCs), each with a finely adjustable clock distribution network to digitize the channels at the fidelity necessary to allow for digital beam forming. The Xilinx produced FX130T Virtex 5 part handles the processing to digitally calibrate each channel as well as filter and beam form the receive signals. Demonstrating the digital processing required for digital beam forming and digital calibration is instrumental to the viability of the proposed DESDynI instrument. The qFSP development brings this implementation to Technology Readiness Level (TRL) 6. This paper will detail the design and development of the prototype qFSP as well as the preliminary results from hardware tests.

  2. Chaotic signals in digital communications

    CERN Document Server

    Eisencraft, Marcio; Suyama, Ricardo

    2013-01-01

    Chaotic Signals in Digital Communications combines fundamental background knowledge with state-of-the-art methods for using chaotic signals and systems in digital communications. The book builds a bridge between theoretical works and practical implementation to help researchers attain consistent performance in realistic environments. It shows the possible shortcomings of the chaos-based communication systems proposed in the literature, particularly when they are subjected to non-ideal conditions. It also presents a toolbox of techniques for researchers working to actually implement such system

  3. Handwritten digits recognition based on immune network

    Science.gov (United States)

    Li, Yangyang; Wu, Yunhui; Jiao, Lc; Wu, Jianshe

    2011-11-01

    With the development of society, handwritten digits recognition technique has been widely applied to production and daily life. It is a very difficult task to solve these problems in the field of pattern recognition. In this paper, a new method is presented for handwritten digit recognition. The digit samples firstly are processed and features extraction. Based on these features, a novel immune network classification algorithm is designed and implemented to the handwritten digits recognition. The proposed algorithm is developed by Jerne's immune network model for feature selection and KNN method for classification. Its characteristic is the novel network with parallel commutating and learning. The performance of the proposed method is experimented to the handwritten number datasets MNIST and compared with some other recognition algorithms-KNN, ANN and SVM algorithm. The result shows that the novel classification algorithm based on immune network gives promising performance and stable behavior for handwritten digits recognition.

  4. Logic of the digital

    CERN Document Server

    Evens, Aden

    2015-01-01

    Building a foundational understanding of the digital, Logic of the Digital reveals a unique digital ontology. Beginning from formal and technical characteristics, especially the binary code at the core of all digital technologies, Aden Evens traces the pathways along which the digital domain of abstract logic encounters the material, human world. How does a code using only 0s and 1s give rise to the vast range of applications and information that constitutes a great and growing portion of our world? Evens' analysis shows how any encounter between the actual and the digital must cross an ontolo

  5. Digital Pulse Modulation Amplifier (PMA) systems based on PEDEC control

    DEFF Research Database (Denmark)

    Nielsen, Karsten

    1999-01-01

    The paper extends previous research and presents a suite of novel high efficiency digital PMA topologies based on Pulse Edge Delay Error Correction (PEDEC). The practical results are very encouraging, showing that digital modulator performance is maintained throughout the subsequent power convers...... conversion. The topologies are believed to be the first implemented digital PMA systems including effective power stage error correction....

  6. 37 CFR 255.4 - Definition of digital phonorecord delivery.

    Science.gov (United States)

    2010-07-01

    ... time or for a specified number of performances. A digital phonorecord delivery includes all... phonorecord delivery. 255.4 Section 255.4 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE, LIBRARY OF... delivery. A “digital phonorecord delivery” is each individual delivery of a phonorecord by digital...

  7. An Interactive Graphics Program for Investigating Digital Signal Processing.

    Science.gov (United States)

    Miller, Billy K.; And Others

    1983-01-01

    Describes development of an interactive computer graphics program for use in teaching digital signal processing. The program allows students to interactively configure digital systems on a monitor display and observe their system's performance by means of digital plots on the system's outputs. A sample program run is included. (JN)

  8. Challenges of Digital Preservation for Cultural Heritage Institutions

    Science.gov (United States)

    Evens, Tom; Hauttekeete, Laurence

    2011-01-01

    This article elaborates four major issues hampering the sustainability of digital preservation within cultural heritage institutions: digitization, metadata indexes, intellectual property rights management and business models. Using a case-study approach, the digitization of audiovisual collections within the performing arts institutions in…

  9. PERFORMANCE

    Directory of Open Access Journals (Sweden)

    M Cilli

    2014-10-01

    Full Text Available This study aimed to investigate the kinematic and kinetic changes when resistance is applied in horizontal and vertical directions, produced by using different percentages of body weight, caused by jumping movements during a dynamic warm-up. The group of subjects consisted of 35 voluntary male athletes (19 basketball and 16 volleyball players; age: 23.4 ± 1.4 years, training experience: 9.6 ± 2.7 years; height: 177.2 ± 5.7 cm, body weight: 69.9 ± 6.9 kg studying Physical Education, who had a jump training background and who were training for 2 hours, on 4 days in a week. A dynamic warm-up protocol containing seven specific resistance movements with specific resistance corresponding to different percentages of body weight (2%, 4%, 6%, 8%, 10% was applied randomly on non consecutive days. Effects of different warm-up protocols were assessed by pre-/post- exercise changes in jump height in the countermovement jump (CMJ and the squat jump (SJ measured using a force platform and changes in hip and knee joint angles at the end of the eccentric phase measured using a video camera. A significant increase in jump height was observed in the dynamic resistance warm-up conducted with different percentages of body weight (p 0.05. In jump movements before and after the warm-up, while no significant difference between the vertical ground reaction forces applied by athletes was observed (p>0.05, in some cases of resistance, a significant reduction was observed in hip and knee joint angles (p<0.05. The dynamic resistance warm-up method was found to cause changes in the kinematics of jumping movements, as well as an increase in jump height values. As a result, dynamic warm-up exercises could be applicable in cases of resistance corresponding to 6-10% of body weight applied in horizontal and vertical directions in order to increase the jump performance acutely.

  10. Biology of Applied Digital Ecosystems

    CERN Document Server

    Briscoe, G; Paperin, G

    2007-01-01

    A primary motivation for research in digital ecosystems is the desire to exploit the self-organising properties of natural ecosystems. Ecosystems are thought to be robust, scalable architectures that can automatically solve complex, dynamic problems. However, the biological processes that contribute to these properties have not been made explicit in digital ecosystem research. Here, we discuss how biological properties contribute to the self-organising features of natural ecosystems. These properties include populations of evolving agents, a complex dynamic environment, and spatial distributions which generate local interactions. The potential for exploiting these properties in artificial systems is then considered. An example architecture, the Digital Business Ecosystem (DBE), is considered in detail. Simulation results imply that the DBE performs better at large scales than a comparable service-oriented architecture. These results suggest that incorporating ideas from theoretical ecology can contribute to u...

  11. Materials Testing - Digital Ecology

    Directory of Open Access Journals (Sweden)

    Seth Wiley

    2013-03-01

    Full Text Available Access to credible building product performance information throughout the design and construction process is critical to enable project development, vet product selections, ensure as-built quality, and successfully complete construction. This is common knowledge and part of common practice for nearly all parties involved in design and construction. The sources of such information can range from vernacular to formal – from common practice to special reference. The focus of this paper is one of the more formal or specialized information sources, performance testing, as well as how such performance testing information can be better used. This paper’s goals are to familiarize the reader with performance testing and to depict a new kind of valuable informational tool (digital ecology. Reference to pertinent nomenclature, description of a real world example, and detailed description of such an informational tool’s values will be provided.The major content of this paper was developed during project-based work and firm-funded internal research at point b design, ltd. over approximately the previous 4 years. The phrase ‘digital ecology’ as herein used is a new concept proposed by the author. The analysis contained in this paper could be applied to the field of operations and maintenance as it is herein applied to design and construction; however, operations and maintenance is beyond the scope of this paper and may be addressed in future papers. It is my hope that this paper will contribute to tangible and real improvements of the built environment via continued, positive development within academic and professional practice.

  12. Provably robust digital watermarking

    Science.gov (United States)

    Chen, Brian; Wornell, Gregory W.

    1999-11-01

    Copyright notification and enforcement, authentication, covert communication, and hybrid transmission are examples of emerging multimedia applications for digital watermarking methods, methods for embedding one signal (e.g., the digital watermark) within another 'host' signal to form a third, 'composite' signal. The embedding is designed to achieve efficient trade-offs among the three conflicting goals of maximizing information-embedding rate, minimizing distortion between the host signal and composite signal, and maximizing the robustness of the embedding. Quantization index modulation (QIM) methods are a class of watermarking methods that achieve provably good rate-distortion-robustness performance. Indeed, QIM methods exist that achieve performance within a few dB of capacity in the case of a (possibly colored) Gaussian host signal and an additive (possibly colored) Gaussian noise channel. Also, QIM methods can achieve capacity with a type of postprocessing called distortion compensation. This capacity is independent of host signal statistics, and thus, contrary to popular belief, the information-embedding capacity when the host signal is not available at the decoder is the same as the case when the host signal is available at the decoder. A low-complexity realization of QIM called dither modulation has previously been proven to be better than both linear methods of spread spectrum and nonlinear methods of low-bit(s) modulation against square-error distortion-constrained intentional attacks. We introduce a new form of dither modulation called spread-transform dither modulation that retains these favorable performance characteristics while achieving better performance against other attacks such as JPEG compression.

  13. Performance-driven design with the support of digital tools: Applying discrete event simulation and space syntax on the design of the emergency department

    Directory of Open Access Journals (Sweden)

    David Morgareidge

    2014-09-01

    This case study demonstrates that DES and SSA are effective tools for facilitating decision-making related to design, reducing capital and operational costs, and improving organizational performance. DES focuses on operational processes and care flow. SSA complements DES with its strength in linking space to human behavior. Combining both tools can lead to high-performance ED design and can extend to broad applications in health care.

  14. Digital Modeling Phenomenon Of Surface Ground Movement

    Directory of Open Access Journals (Sweden)

    Ioan Voina

    2016-11-01

    Full Text Available With the development of specialized software applications it was possible to approach and resolve complex problems concerning automating and process optimization for which are being used field data. Computerized representation of the shape and dimensions of the Earth requires a detailed mathematical modeling, known as "digital terrain model". The paper aims to present the digital terrain model of Vulcan mining, Hunedoara County, Romania. Modeling consists of a set of mathematical equations that define in detail the surface of Earth and has an approximate surface rigorously and mathematical, that calculated the land area. Therefore, the digital terrain model means a digital representation of the earth's surface through a mathematical model that approximates the land surface modeling, which can be used in various civil and industrial applications in. To achieve the digital terrain model of data recorded using linear and nonlinear interpolation method based on point survey which highlights the natural surface studied. Given the complexity of this work it is absolutely necessary to know in detail of all topographic elements of work area, without the actions to be undertaken to project and manipulate would not be possible. To achieve digital terrain model, within a specialized software were set appropriate parameters required to achieve this case study. After performing all steps we obtained digital terrain model of Vulcan Mine. Digital terrain model is the complex product, which has characteristics that are equivalent to the specialists that use satellite images and information stored in a digital model, this is easier to use.

  15. Digital communications over fading channels

    OpenAIRE

    Beltz, Nathan E.; Robertson, R. Clark

    2004-01-01

    In this report, the probabilities of bit error for the most commonly used digital modulation techniques are analyzed. Analytic solutions are developed for the probability of bit error when the signal is affected by the most commonly encountered impairment to system performance for a wireless channel, the transmission of the signal over a fading channel. In this report, the effect of a slow, flat Ricean fading channel on communications systems performance is examined. Since channel fading ...

  16. Digital electronic engine control history

    Science.gov (United States)

    Putnam, T. W.

    1984-01-01

    Full authority digital electronic engine controls (DEECs) were studied, developed, and ground tested because of projected benefits in operability, improved performance, reduced maintenance, improved reliability, and lower life cycle costs. The issues of operability and improved performance, however, are assessed in a flight test program. The DEEC on a F100 engine in an F-15 aircraft was demonstrated and evaluated. The events leading to the flight test program are chronicled and important management and technical results are identified.

  17. Comparison of flight results with digital simulation for a digital electronic engine control in an F-15 airplane

    Science.gov (United States)

    Myers, L. P.; Burcham, F. W., Jr.

    1983-01-01

    Substantial benefits of a full authority digital electronic engine control on an air breathing engine were demonstrated repeatedly in simulation studies, ground engine tests, and engine altitude test facilities. A digital engine electronic control system showed improvements in efficiency, performance, and operation. An additional benefit of full authority digital controls is the capability of detecting and correcting failures and providing engine health diagnostics.

  18. Design guidelines for SAR digital receiver/exciter boards.

    Energy Technology Data Exchange (ETDEWEB)

    Dudley, Peter A.

    2009-08-01

    High resolution radar systems generally require combining fast analog to digital converters and digital to analog converters with very high performance digital signal processing logic. These mixed analog and digital printed circuit boards present special challenges with respect to electromagnetic interference. This document first describes the mechanisms of interference on such boards then follows up with a discussion of prevention techniques and finally provides a checklist for designers to help avoid common mistakes.

  19. On the digital homology groups of digital images

    CERN Document Server

    Lee, Dae-Woong

    2011-01-01

    In this article we study the digital homology groups of digital images which are based on the singular homology groups of topological spaces in algebraic topology. Specifically, we define a digitally standard $n$-simplex, a digitally singular $n$-simplex, and the digital homology groups of digital images with $k$-adjacency relations. We then construct a covariant functor from a category of digital images and digitally continuous functions to the one of abelian groups and group homomorphisms, and investigate some fundamental and interesting properties of digital homology groups of digital images, such as the digital version of the dimension axiom which is one of the Eilenberg-Steenrod axioms.

  20. Digital chest radiography: collimation and dose reduction

    DEFF Research Database (Denmark)

    Debess, Jeanne; Johnsen, Karen Kirstine; Vejle-Sørensen, Jens Kristian

    Purpose: Quality improvement of basic radiography focusing on collimation and dose reduction in digital chest radiography Methods and Materials:A retrospective study of digital chest radiography is performed to evaluate the primary x-ray tube collimation of the PA and lateral radiographs. Data from...... of clinical supervisors. Optimal collimation is determined by European and Regional Danish guidelines. The areal between current and optimal collimation is calculated. The experimental research is performed in September - October 2014 Siemens Axiom Aristos digital radiography system DR using 150 kV, 1,25 -3...

  1. Digital rectal exam

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007069.htm Digital rectal exam To use the sharing features on this page, please enable JavaScript. A digital rectal exam is an examination of the lower ...

  2. Identidad visual digital

    OpenAIRE

    Pérez Villanueva, Alba

    2013-01-01

    Se estudian seis casos de empresas de diferentes sectores y la adaptación de la identidad visual digital para obtener una imagen aproximada sobre el estado de la identidad visual digital de las coporaciones

  3. Coastal California Digital Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This digital ortho-imagery dataset is a survey of coastal California. The project area consists of approximately 3774 square miles. The project design of the digital...

  4. About group digital signatures

    National Research Council Canada - National Science Library

    Adriana Cristina Enache

    2012-01-01

    ...).A group digital signature is a digital signature with enhanced privacy features that allows members of a given group to anonymously sign messages on behalf of the group, producing a group signature...

  5. Research study on IPS digital controller design

    Science.gov (United States)

    Kuo, B. C.; Folkerts, C.

    1976-01-01

    The performance is investigated of the simplified continuous-data model of the Instrument Pointing System (IPS). Although the ultimate objective is to study the digital model of the system, knowledge on the performance of the continuous-data model is important in the sense that the characteristics of the digital system should approach those of the continuous-data system as the sampling period approaches zero.

  6. Advanced Digital Signal Processing for Hybrid Lidar

    Science.gov (United States)

    2014-10-30

    Technical 4. TITLE AND SUBTITLE Advance Digital Signal Processing for Hybrid Lidar 6. AUTHOR(S) William D. Jemison 7. PERFORMING ORGANIZATION NAME(S...development of signed processing algorithms for hybrid lidar - radar designed to improve detection performance. 15. SUBJECT TERMS Hybrid Lidar - Radar 16...Award Number N000141110371 Title of Research Advanced Digital Signal Processing for Hybrid Lidar Principal Investigator William D. Jemison

  7. Digital Inkjet Textile Printing

    OpenAIRE

    Wang, Meichun

    2017-01-01

    Digital inkjet textile printing is an emerging technology developed with the rise of the digital world. It offers a possibility to print high-resolution images with unlimited color selection on fabrics. Digital inkjet printing brings a revolutionary chance for the textile printing industry. The history of textile printing shows the law how new technology replaces the traditional way of printing. This indicates the future of digital inkjet textile printing is relatively positive. Differen...

  8. Basic digital signal processing

    CERN Document Server

    Lockhart, Gordon B

    1985-01-01

    Basic Digital Signal Processing describes the principles of digital signal processing and experiments with BASIC programs involving the fast Fourier theorem (FFT). The book reviews the fundamentals of the BASIC program, continuous and discrete time signals including analog signals, Fourier analysis, discrete Fourier transform, signal energy, power. The text also explains digital signal processing involving digital filters, linear time-variant systems, discrete time unit impulse, discrete-time convolution, and the alternative structure for second order infinite impulse response (IIR) sections.

  9. Digital dannelse til gymnasieeleverne

    DEFF Research Database (Denmark)

    Kaarsted, Thomas; Holch Andersen, Knud

    2012-01-01

    Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene.......Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene....

  10. Digital flight control research

    Science.gov (United States)

    Potter, J. E.; Stern, R. G.; Smith, T. B.; Sinha, P.

    1974-01-01

    The results of studies which were undertaken to contribute to the design of digital flight control systems, particularly for transport aircraft are presented. In addition to the overall design considerations for a digital flight control system, the following topics are discussed in detail: (1) aircraft attitude reference system design, (2) the digital computer configuration, (3) the design of a typical digital autopilot for transport aircraft, and (4) a hybrid flight simulator.

  11. Online Digital Trading

    Directory of Open Access Journals (Sweden)

    Felician Alecu

    2013-09-01

    Full Text Available This paper summarizes the main options a digital content creator has in order to obtain money by online trading of digital works. There are multiple ways to get paid for the digital products, like licensing, for example, however this article tries to present the most successful business models targeting the online market. The exclusive rights stated by the copyright laws are helping the authors to maximize to potential advantages coming from their digital creations.

  12. Interactive Digital Signal Processor

    Science.gov (United States)

    Mish, W. H.

    1985-01-01

    Interactive Digital Signal Processor, IDSP, consists of set of time series analysis "operators" based on various algorithms commonly used for digital signal analysis. Processing of digital signal time series to extract information usually achieved by applications of number of fairly standard operations. IDSP excellent teaching tool for demonstrating application for time series operators to artificially generated signals.

  13. Digital Literacy. Research Brief

    Science.gov (United States)

    Williamson, Ronald

    2011-01-01

    21st Century students need a complex set of skills to be successful in a digital environment. Digital literacy, similar to traditional definitions of literacy, is a set of skills students use to locate, organize, understand, evaluate and create information. The difference is that it occurs in an environment where a growing set of digital tools…

  14. Personal Digital Video Stories

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Henningsen, Birgitte Sølbeck; Louw, Arnt Vestergaard

    2016-01-01

    agenda focusing on video productions in combination with digital storytelling, followed by a presentation of the digital storytelling features. The paper concludes with a suggestion to initiate research in what is identified as Personal Digital Video (PDV) Stories within longitudinal settings, while...

  15. Digital language death.

    Directory of Open Access Journals (Sweden)

    András Kornai

    Full Text Available Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide.

  16. Behandlingseffekt af Digital Dermatitis

    DEFF Research Database (Denmark)

    Krogh, Kenneth; Thomsen, Peter

    2008-01-01

    af klovlidelser herunder især Digital Dermatitis. Klovregistreringerne viser, at der er stor dynamik og mange nyinfektioner af Digital Dermatitis svarende til problematikken ved mastitis. Behandlingseffekten ved Digital Dermatitis er høj (omkring 90 %) ved den udførte behandling. Behandlingen bestod...

  17. Digitization in Maritime Industry

    DEFF Research Database (Denmark)

    Constantiou, Ioanna; Shollo, Arisa; Kreiner, Kristian

    2017-01-01

    Digitization in the maritime industry is expected to transform businesses. The recently introduced mobile technologies in inter-organizational processes is an example of digitization in an industry which moves very slowly towards digital transformation. We focus on the influence of mobile...

  18. Behandlingseffekt af Digital Dermatitis

    DEFF Research Database (Denmark)

    Krogh, Kenneth; Thomsen, Peter

    2008-01-01

    af klovlidelser herunder især Digital Dermatitis. Klovregistreringerne viser, at der er stor dynamik og mange nyinfektioner af Digital Dermatitis svarende til problematikken ved mastitis. Behandlingseffekten ved Digital Dermatitis er høj (omkring 90 %) ved den udførte behandling. Behandlingen bestod...

  19. Reconceptualising Critical Digital Literacy

    Science.gov (United States)

    Pangrazio, Luciana

    2016-01-01

    While it has proved a useful concept during the past 20 years, the notion of "critical digital literacy" requires rethinking in light of the fast-changing nature of young people's digital practices. This paper contrasts long-established notions of "critical digital literacy" (based primarily around the critical consumption of…

  20. Reconceptualising Critical Digital Literacy

    Science.gov (United States)

    Pangrazio, Luciana

    2016-01-01

    While it has proved a useful concept during the past 20 years, the notion of "critical digital literacy" requires rethinking in light of the fast-changing nature of young people's digital practices. This paper contrasts long-established notions of "critical digital literacy" (based primarily around the critical consumption of…

  1. Preparing collections for digitization

    CERN Document Server

    Bulow, Anna E

    2010-01-01

    Most libraries, archives and museums are confronting the challenges of providing digital access to their collections. This guide offers guidance covering the end-to-end process of digitizing collections, from selecting records for digitization to choosing suppliers and equipment and dealing with documents that present individual problems.

  2. Digital subtraction laryngography

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B.W.; Enzmann, D.R.; Hopp, M.L.; Castellino, R.A.

    1983-06-01

    Digital subtraction laryngography was used to evaluate laryngeal function in 8 patients: 4 with normal larynxes and 4 with laryngeal disease. Subtracted digital images provided a dynamic display of the extent and symmetry of vocal cord excursions and pyriform sinus inflation, and the vocal cord resting position was also clearly depicted. The technical details of digital subtraction laryngography and its application are described.

  3. Digital Tectonic Tools

    DEFF Research Database (Denmark)

    Schmidt, Anne Marie Due

    2005-01-01

    in particular. A model of the aspects in the term tectonics – epresentation, ontology and culture – will be presented and used to discuss the current digital tools’ ability in tectonics. Furthermore it will be discussed what a digital tectonic tool is and could be and how a connection between the digital...

  4. A Digital Badging Dataset Focused on Performance, Engagement and Behavior-Related Variables from Observations in Web-Based University Courses

    Science.gov (United States)

    McDaniel, Rudy; Fanfarelli, Joseph R.

    2015-01-01

    This dataset contains participant data related to the use of badging (achievement) feedback in pedagogical design. Two sections each of web-based graphic design and web design undergraduate courses were offered at the University of Central Florida. A badging system for achievements was included in one section of each. Performance, engagement and…

  5. Perspectives on Language Sustainability in a Performance Era: Discourses, Policies, and Practices in a Digital and Social Media Campaign to Revitalise Irish

    Directory of Open Access Journals (Sweden)

    Kelly-Holmes Helen

    2017-08-01

    Full Text Available The poststructuralist turn has been widely acknowledged in contemporary applied and sociolinguistics (Rampton 2006, Blommaert 2010. While for many this paradigmatic shift has been a welcome challenge to segregationalist approaches (Mühlhäusler 1996, Makoni and Pennycook 2007 and deficit discourses in relation to multilingualism (Jacquemet 2005, Jaffe 2007, it is not an unproblematic concept for minority language media and language sustainability. For those committed to activism and engagement with policy makers, the current paradigmatic shift, which has been described in terms of a performance era for minority language media (Pietikäinen and Kelly-Holmes 2011, presents particular challenges which have the potential to undermine gains made in previous eras in relation to media rights for minority language speakers. Using the example of a recent multi-media campaign to revitalise Irish, the Bród Club, this paper explores the opportunities and problems presented by the contemporary performance era for minority language media.

  6. Digitally assisted pipeline ADCs theory and implementation

    CERN Document Server

    Murmann, Boris

    2007-01-01

    List of Figures. List of Tables. Acknowledgements. Preface. 1: Introduction. 1. Motivation. 2. Overview. 3. Chapter Organization. 2: Performance Trends. 1. Introduction. 2. Digital Performance Trends. 3. ADC Performance Trends. 3: Scaling Analysis. 1. Introduction. 2. Basic Device Scaling from a Digital Perspective. 3. Technology Metrics for Analog Circuits. 4. Scaling Impact on Matching-Limited Circuits. 5. Scaling Impact on Noise-Limited Circuits. 4: Improving Analog Circuit Efficiency. 1. Introduction. 2. Analog Circuit Challenges. 3. The Cost of Feedback. 4. Two-Stage Feedback Amplifier vs. Open-Loop Gain Stage. 5. Discussion. 5: Open-Loop Pipelined ADCs. 1. A Brief Review of Pipelined ADCs. 2. Conventional Stage Implementation. 3. Open-Loop Pipeline Stages. 4. Alternative Transconductor Implementations. 6: Digital Nonlinearity Correction. 1. Overview. 2. Error Model and Digital Correction. 3. Alternative Error Models. 7: Statistics-Based Parameter Estimation. 1. Introduction. 2. Modulation Approach. 3. R...

  7. Bodies and real-time interfaces: in video performance and interactive digital 3D installation art by VALIE EXPORT and Jette Gejl Kristensen

    Directory of Open Access Journals (Sweden)

    Ulla Angkjær Jørgensen

    2012-06-01

    Full Text Available This article considers the interface as the physical interaction of human body and technology inspired by the theories of Maurizio Lazzarato, Brian Massumi, and Anna Munster. Through artworks by VALIE EXPORT (Adjunct Dislocations II and Jette Gejl Kristensen (Hyperkinetic Kayak it examines how bodies and advanced technology together perform real-time interfaces in concrete spaces launching complex events of affective encounters.

  8. Digital front-end module (DFEM) series; Digital front end module (DFEM) series

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    The digital front-end module (DFEM) is a module in which the processes ranging from the reception of digitally modulated radiofrequencies to the output of digital IF (Intermediate Frequency) signals or data streams are integrated. Beginning with a module for the MCNS (Multimedia Cable Network System) cable modem which was the first module in this business field approved by the Cable Labs, U.S., Toshiba has developed a series of DFEMs for various digital media for satellites, ground waves, and CATV (Cable Television) systems. The series is characterized by (1) the serialization of DFEMs compatible with various digital modulation techniques such as 8 PSK (Phase Shift Keying), OFDM (Orthogonal Frequency Division Multiplexing), and 256 QAM (Quadrature Amplitude Modulation), (2) easy connection with digital circuits thanks to the high shielding effect, and (3) the achievement of smaller size, higher performance, and lower power consumption. (translated by NEDO)

  9. Soundscapes/Artabilitation - Evolution of a Hybrid Human Performance Concept, Method & Apparatus Where Digital Interactive Media, The Arts, & Entertainment are Combined

    Science.gov (United States)

    Brooks, A. L.

    'SoundScapes' is a body of empirical research that for almost two decades has focused upon investigating noninvasive gesture control of multi-sensory stimuli and potential uses in therapy and the arts. In this context noninvasive gesture refers to motion in invisible activity zones of a system input device utilizing technology outside of human vision. Especially targeted are disabled people of all ages, and special focus has been on the profoundly impaired who especially have limited opportunities for creative self-articulation and playful interaction. The concept has been explored in various situations including: - live stage performances; interactive room installations for museums, workshops, and festivals; and in health-care sessions at hospitals, institutes and special schools. Multifaceted aspects continuously cross-inform in a systemic manner, and each situation where the motion-sensitive environment is applied is considered as a hybrid system. Whilst simplistic in concept, i.e. learning by playful and creative doings, inherent are complexities of optimizing the interactive system to user-experience and evaluation of same. This chapter presents the system in context to its conceived-for-target community; it also presents the parallel practice-led investigations in performance art. Reciprocal design and reflective cross-analysis of the activities has resulted such that performance informs design and strategies of intervention and evaluation with impaired users, and vice versa.

  10. Analog/RF performance of L- and U-shaped channel tunneling field-effect transistors and their application as digital inverters

    Science.gov (United States)

    Wang, Qianqiong; Wang, Shulong; Liu, Hongxia; Li, Wei; Chen, Shupeng

    2017-06-01

    The inverter performance comparisons of L- and U-shaped channel tunneling field-effect transistors (LTFET and UTFET) are investigated by using Sentaurus TCAD tool. The RF figures of merit for these two TFETs are analyzed in terms of transconductance (g m), output conductance (g ds), gate capacitance (C gg), gate-to-source capacitance (C gs), gate-to-drain capacitance (C gd), unit-gain cut-off frequency (f T), the maximum frequency of oscillation (f MAX) and gain bandwidth product (GBW). The simulation results reveal that LTFET and UTFET have the similar DC characteristic due to the identical tunneling process. And the better RF performance LTFET provides due to it has the much smaller C gd than UTFET. Meanwhile, this work uses mixed device-circuit simulations to predict the performance of inverter circuit implemented with LTFET and UTFET for the first time. And the calculated results demonstrate LTFET is more optimization for inverter circuit design in the novel generation transistors. And all the simulation results in this paper can be used as a reference to choose the characteristic parameters of novel TFETs for inverter applications.

  11. A new program on digitizing analog seismograms

    Science.gov (United States)

    Wang, Maofa; Jiang, Qigang; Liu, Qingjie; Huang, Meng

    2016-08-01

    Historical seismograms contain a great variety of useful information which can be used in the study of earthquakes. It is necessary for researchers to digitize analog records and extract the information just as modern computing analysis requires. Firstly, an algorithm based on color scene filed method is presented in order to digitize analog seismograms. Secondly, an interactive software program using C# has been developed to digitize seismogram traces from raster files quickly and accurately. The program can deal with gray-scale images stored in a suitable file format and it offers two different methods: manual digitization and automatic digitization. The test result of the program shows that the methods presented in this paper can lead to good performance.

  12. Detecting Copy Move Forgery In Digital Images

    Science.gov (United States)

    Gupta, Ashima; Saxena, Nisheeth; Vasistha, S. K.

    2012-03-01

    In today's world several image manipulation software's are available. Manipulation of digital images has become a serious problem nowadays. There are many areas like medical imaging, digital forensics, journalism, scientific publications, etc, where image forgery can be done very easily. To determine whether a digital image is original or doctored is a big challenge. To find the marks of tampering in a digital image is a challenging task. The detection methods can be very useful in image forensics which can be used as a proof for the authenticity of a digital image. In this paper we propose the method to detect region duplication forgery by dividing the image into overlapping block and then perform searching to find out the duplicated region in the image.

  13. Direct-Digital-Drive Microring Modulator

    CERN Document Server

    Ehrlichman, Yossef; Ruschin, Shlomo

    2016-01-01

    The method of Direct Digital Drive is applied to a microring resonator. The microring resonator is thus controlled by a segmented set of electrodes each of which is driven by binary (digital) signal. Digital linearization is performed with the aid of digital memory lookup table. The method is applied to a single microring modulator to provide an M-bit digital-toanalog converter (DAC), which may also be viewed as an M-level pulse amplitude modulator (M-PAM). It is shown, by means of simulation, that a 4-bit DAC can achieve an effective number of bits (ENOB) of 3.74bits. Applying the same method for two rings, enables the generation of two-dimensional optical M-QAM signals. It is shown, by means of simulation, that a 16-QAM modulator achieves an EVM better than -30dB.

  14. Ageing and digital games

    DEFF Research Database (Denmark)

    Iversen, Sara Mosberg

    2016-01-01

    Digital games are still to a great degree considered a medium mainly for young boys. However, available statistics on Western media use show that this is far from the case. Increasingly, people of all ages and genders play digital games, also older adults in their early 60s and beyond. The aim...... of the book is to examine, analyse and discuss: 1) What older adults do with digital games and what meanings the use of digital games take on in the everyday life of older adults; 2) How older adults are perceived by society in relation to digital games; 3) How play and games can be used both...

  15. Digit Replantation The First 50 Years.

    Science.gov (United States)

    Hadley, Scott R; Capo, John T

    2015-06-01

    Since the first successful digit replantation by Japanese surgeons Komatsu and Tamai, the past half century has seen the field of digit replantation in the USA experience exponential growth followed by a steady decline in volume of cases and percentage of successful viable digits. The initial enthusiasm and technical progress of digital replantation has been tempered by mediocre functional outcomes, rising healthcare costs, and limited healthcare resources. The history and approach to digit replantation is reviewed and highlights the likely push toward the development of regional replant centers staffed by highly skilled teams to improve the functional outcomes following these complex procedures. More than 50 years have passed since the first successful digit replantation by Komatsu and Tamai who replanted a sharply amputated thumb in a 28-year-old male at the metacarpal-phalangeal joint level in a 4.5 hour procedure. Two arteries and 2 veins were anastomosed using 8-0 monofilament nylon and 7-0 braided silk suture. The patient remained in the hospital for 40 days and did not return to work for 4 months. News of this triumph of microvascular skill was heralded throughout the world as the first successful replantation of a completely amputated digit. Over the past half century, the field of digit replantation in the USA experienced exponential growth followed by a steady decline in volume of cases and percentage of successful viable digits. The initial enthusiasm and technical progress of digital replantation has been tempered by mediocre functional outcomes, rising healthcare costs, and limited healthcare resources. In the next 50 years, it is possible that the majority of digit replantation procedures in the USA may be performed in tertiary centers or regional replant centers by highly skilled teams.

  16. Digital Optical Control System

    Science.gov (United States)

    Jordan, David H.; Tipton, Charles A.; Christmann, Charles E.; Hochhausler, Nils P.

    1988-09-01

    We describe the digital optical control system (DOGS), a state-of-the-art controller for electrical feedback in an optical system. The need for a versatile optical controller arose from a number of unique experiments being performed by the Air Force Weapons Laboratory. These experiments use similar detectors and actuator-controlled mirrors, but the control requirements vary greatly. The experiments have in common a requirement for parallel control systems. The DOGS satisfies these needs by allowing several control systems to occupy a single chassis with one master controller. The architecture was designed to allow upward compatibility with future configurations. Combinations of off-the-shelf and custom boards are configured to meet the requirements of each experiment. The configuration described here was used to control piston error to X/80 at a wavelength of 0.51 Am. A peak sample rate of 8 kHz, yielding a closed loop bandwidth of 800 Hz, was achieved.

  17. Digital Radiation image

    Directory of Open Access Journals (Sweden)

    Abou-Bakr Ramadan

    2012-03-01

    Full Text Available This work introduces a new way for data visualization. Its name is Digital Application name' Image. Normal digital image is created by digital camera or digital scanner but digital application name image is created by measurements of monitoring data. This work uses the data which is measured by radiation monitoring station and classifies it using fuzzy logic rules to create digital radiation image. The main unique advantage of digital radiation image is that it expresses thousands of measurements in a very clear form through only one picture while the maximum number of measurements does not exceed 100 with other conventional visualization methods. This feature gives a facility to view one year of all recorded measurements in only one photo. This picture helps the user to observe the behavior of thousands of measurements in few minutes instead of spending few hours for reviewing hundreds of charts for the same measurements.

  18. The Profiles in Science Digital Library: Behind the Scenes.

    Science.gov (United States)

    Gallagher, Marie E; Moffatt, Christie

    2012-01-01

    This demonstration shows the Profiles in Science® digital library. Profiles in Science contains digitized selections from the personal manuscript collections of prominent biomedical researchers, medical practitioners, and those fostering science and health. The Profiles in Science Web site is the delivery mechanism for content derived from the digital library system. The system is designed according to our basic principles for digital library development [1]. The digital library includes the rules and software used for digitizing items, creating and editing database records and performing quality control as well as serving the digital content to the public. Among the types of data managed by the digital library are detailed item-level, collection-level and cross-collection metadata, digitized photographs, papers, audio clips, movies, born-digital electronic files, optical character recognized (OCR) text, and annotations (see Figure 1). The digital library also tracks the status of each item, including digitization quality, sensitivity of content, and copyright. Only items satisfying all required criteria are released to the public through the World Wide Web. External factors have influenced all aspects of the digital library's infrastructure.

  19. Digital Collections, Digital Libraries and the Digitization of Cultural Heritage Information.

    Science.gov (United States)

    Lynch, Clifford

    2002-01-01

    Discusses the development of digital collections and digital libraries. Topics include digitization of cultural heritage information; broadband issues; lack of compelling content; training issues; types of materials being digitized; sustainability; digital preservation; infrastructure; digital images; data mining; and future possibilities for…

  20. Digital rights management for digital cinema

    Science.gov (United States)

    Kirovski, Darko; Peinado, Marcus; Petitcolas, Fabien A. P.

    2001-12-01

    There is a wide consensus among the feature film production studios that the Internet era brings a new paradigm for film distribution to cinemas worldwide. The benefits of digital cinema to both producers and cinemas are numerous: significantly lower distribution and maintenance costs, immediate access to film libraries, higher presentation quality, and strong potential for developing new business models. Despite these advantages, the studios are still reluctant to jump into the digital age. The main showstopper for digital cinema is the danger of widespread piracy. Piracy already costs Hollywood an estimated two billion dollars annually and digital cinema without proper copyright enforcement could increase this number. In this paper, we present a copyright management system that aims at providing the set of necessary security tools: standard cryptographic primitives and copyright protection mechanisms that enable a reliable and secure feature film delivery system.