Tomography

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Tomography refers to imaging by sections or sectioning, through the use of any kind of penetrating wave. A device used in tomography is called a tomograph, while the image produced is a tomogram. (Wikipedia.org)






Conferences related to Tomography

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2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)

The NSS/MIC offers an outstanding opportunity for scientists and engineers interested in the fields of nuclear science, radiation detection, accelerators, high energy physics and astrophysics, and related software to present their latest developments and ideas. The scientific program provides a comprehensive review of the latest developments in technology and covers a wide range of applications from radiation and accelerator instrumentation, new detector materials, to complex detector systems for physical sciences, and advanced imaging systems for biological and medical research.

  • 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)

    The scope of the conference is to present advancements in the field of nuclear science (detectors, electronics and algorithms) as applied to high energy and nuclear physics, as well as various imaging techniques used in Medicine. The conference fosters interactions between instrumentation research and 'end user' application expertise, thus highlighting interdisciplinary aspects of nuclear science.

  • 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (2014 NSS/MIC)

    The conference emphasizes the latest developments in technology and instrumentation and their implementation in experiments for space, accelerators, other radiation environments, homeland security, and Medical Imaging Sciences

  • 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)

    Detectors, software, signal processing and systems for ionizing radiation. Medical imaging detector and system development for PET, SPECT and other imaging based on nuclear techniques.

  • 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference (2012 NSS/MIC)

    Forum for exchange of scientist and engineers working Nuclear Physics and Medical Imaging in technology and instrumentation and their implementation in experiments for particle physics, space, accelerators and other applications of radiation detection such as the technological and mathematical aspects of radiotracer-based medical imaging and other areas of non-Nuclear Molecular Imaging technologies.

  • 2011 IEEE Nuclear Science Symposium and Medical Imaging Conference (2011 NSS/MIC)

    Detectors, software, signal processing and systems for ionizing radiation. Medical imaging detector and system development for PET, SPECT and other imaging based on nuclear techniques.

  • 2010 IEEE Nuclear Science Symposium and Medical Imaging Conference (2010 NSS/MIC)

    Detectors, software, signal processing and systems for ionizing radiation. Medical imaging detector and system development for PET, SPECT and other imaging based on nuclear techniques.

  • 2009 IEEE Nuclear Science Symposium and Medical Imaging Conference (2009 NSS/MIC)

    Radiation Detectors and Instrumentation and their applications in Physics, Biology, Space,Material Science,Medical Physics, and Homeland Security


2014 IEEE International Instrumentation and Measurement Technology Conference (I2MTC)

The Conference focuses on all aspects of instrumentation and measurement science and technology research, development and applications. The list of program topics includes but is not limited to: Measurement Science & Education, Measurement Systems, Measurement Data Acquisition, Measurements of Physical Quantities, and Measurement Applications.

  • 2013 IEEE International Instrumentation and Measurement Technology Conference (I2MTC)

    The Conference focuses on all aspects of instrumentation and measurement science and technology research, development and applications. The list of program topics includes but is not limited to MEASUREMENT SCIENCE & EDUCATION, MEASUREMENT SYSTEMS, MEASUREMENT -DATA ACQUISITION, MEASUREMENTS OF PHYSICAL QUANTITIES, and MEASUREMENT APPLICATIONS.

  • 2012 IEEE International Instrumentation and Measurement Technology Conference (I2MTC)

    The conference focuses on research, development and applications in the field of instrumentation and measurement science and technology. The list of program topics includes but is not limited to Fundamentals, Sensors & Transducers, Measurements of Physical Qualities, Measurement Systems, Measurement Applications, Signal & Image Processing, and Industrial Applications.

  • 2011 IEEE International Instrumentation and Measurement Technology Conference (I2MTC)

    The Conference focuses on all aspects of instrumentation and measurement science and technology research, development and applications. The list of program topics includes but is not limited to MEASUREMENT SCIENCE & EDUCATION, MEASUREMENT SYSTEMS, MEASUREMENT -DATA ACQUISITION, MEASUREMENTS OF PHYSICAL QUANTITIES, and MEASUREMENT APPLICATIONS.

  • 2010 IEEE Instrumentation & Measurement Technology Conference - I2MTC 2010

    The Conference focuses on all aspects of instrumentation and measurement science and technology research, development and applications. The list of program topics includes but is not limited to MEASUREMENT SCIENCE & EDUCATION, MEASUREMENT SYSTEMS, MEASUREMENT -DATA ACQUISITION, MEASUREMENTS OF PHYSICAL QUANTITIES, and MEASUREMENT APPLICATIONS.

  • 2009 IEEE Instrumentation & Measurement Technology Conference - I2MTC 2009

    The Conference focuses on all aspects of instrumentation and measurement science and technology research, development and applications. The list of program topics includes but is not limited to MEASUREMENT SCIENCE & EDUCATION, MEASUREMENT SYSTEMS, MEASUREMENT-DATA ACQUISITION, MEASUREMENTS OF PHYSICAL QUANTITIES, and MEASUREMENT APPLICATIONS.

  • 2008 IEEE Instrumentation & Measurement Technology Conference - I2MTC 2008

    The conference focuses on all aspects of instrumentation and measurement science and technology - research, development and applications. The list of program topics includes but is not limited to measurement science & education, measurement systems, measurement data acquisition, measurements of physical quantities, and measurement applications.


2013 Conference on Lasers and Electro-Optics (CLEO)

CLEO serves as the premier international forum for scientific and technical optics, uniting the fields of lasers and opto-electronics by bringing together all aspects of laser technology, from basic research to industry applications.

  • 2012 Conference on Lasers and Electro-Optics (CLEO)

    CLEO 2012 features a complete and up-to-date technical program under three core conferences; CLEO: QELS- Fundamental Science, CLEO: Science & Innovations, and CLEO: Applications & Technology. CLEO: Expo and Market Focus bring CLEO 2012 full circle by highlighting the latest innovations and products as well as providing a forum to discuss marketplace trends and challenges.

  • 2011 Conference on Lasers and Electro-Optics (CLEO)

    CLEO, the Conference on Lasers and Electro-Optics, formerly known as CLEO/QELS, serves as the premier international forum for scientific and technical optics. The CLEO: 2011 Conference unites the fields of lasers and opto-electronics by bringing together all aspects of laser technology, from basic research to industry applications.

  • 2010 Conference on Lasers and Electro-Optics (CLEO)

    CLEO is held in conjunction with the Quantum Electronics and Laser Science Conference. CLEO/QELS attracts leaders in the fields of lasers, optical devices, optical fibers, photonics and innovative approaches in such fields as: laser spectroscopy, ultrafast optics, nonlinear optics, optical detectors, optical modulators, optical pulses, and quantum mechanics.

  • 2009 Conference on Lasers and Electro-Optics (CLEO)

    CLEO has evolved into a dynamic six-day event that has successfully bridged the science and applications sides of the optics and photonics industry. CLEO offers high-quality programming; the latest in the lasers, electro-optics and photonics industry; the CLEO Exhibit, which has over 350 participating companies; and a new location in Baltimore, Maryland. CLEO and PhAST 2008 is the must attend event of the year.

  • 2008 Conference on Lasers and Electro-Optics (CLEO)

    CLEO/QELS and PhAST has evolved into a dynamic six-day event that has successfully bridged the science and applications sides of the optics and photonics industry. CLEO/QELS offers high-quality programming; the latest in the lasers, electro-optics and photonics industry; the CLEO Exhibit, which has over 350 participating companies; and a new location in San Jose, California. CLEO/QELS and PhAST 2008 is the must attend event of the year.


2013 IEEE International Conference on Imaging Systems and Techniques (IST)

IST’2013 deals with the design, development, evaluation and applications of imaging systems, instrumentation, and measuring techniques, to enhance detection and image quality. Applications for aerospace, medicine and biology, molecular imaging, metrology, Ladars and Lidars, radars, homeland security, and industrial imaging, with emphasis on industrial and medical tomography, corrosion imaging, and non-destructive evaluation (NDE), will be covered. systems, instrumentation, and measuring techniques, to enhance detection and image quality.Applications for aerospace, medicine and biology, molecular imaging, metrology, ladar and lidars, radars,homeland security, and industrial imaging with emphasis on industrial tomography, corrosion imaging,and non-destructive evaluation (NDE) will be covered.

  • 2012 IEEE International Conference on Imaging Systems and Techniques (IST)

    IST 2012 deals with the design, development, evaluation and applications of imaging systems, instrumentation, and measuring techniques, to enhance detection and image quality. Applications for aerospace, medicine and biology, molecular imaging, metrology, ladars and lidars, radars, homeland security, and industrial imaging with emphasis on industrial tomography, corrosion imaging, and non-destructive evaluation (NDE) will be covered.

  • 2011 IEEE International Conference on Imaging Systems and Techniques (IST)

    IST 2011 deals with the design, development, evaluation and applications of imaging systems, instrumentation, and measuring techniques, to enhance detection and image quality. Applications for aerospace, medicine and biology, molecular imaging, metrology, ladar and lidars, radars, homeland security, and industrial imaging with emphasis on industrial tomography, corrosion imaging, and non-destructive evaluation (NDE) will be covered.

  • 2010 IEEE International Conference on Imaging Systems and Techniques (IST)

    IST2009 deals with the design, development, evaluation and applications of imaging systems, instrumentation, and measuring techniques, to enhance detection and image quality. Applications for aerospace, medicine and biology, molecular imaging, metrology, ladar and lidars, radars, homeland security, and industrial imaging with emphasis on industrial tomography, corrosion imaging, and non-destructive evaluation (NDE) will be covered.

  • 2009 IEEE International Workshop on Imaging Systems and Techniques (IST)

    IST2009 deals with the design, development, evaluation and applications of imaging systems, instrumentation, and measuring techniques, to enhance detection and image quality. Applications for aerospace, medicine and biology, molecular imaging, metrology, ladar and lidars, radars, homeland security, and industrial imaging with emphasis on industrial tomography, corrosion imaging, and non-destructive evaluation (NDE) will be covered.


2012 Chinese Control Conference (CCC)

The Chinese Control Conference (CCC) is an annual international conference organized by the Technical Committee on Control Theory (TCCT), Chinese Association of Automation (CAA). It provides a forum for scientists and engineers over the world to present their new theoretical results and techniques in the field of systems and control. The conference consists of pre-conference workshops, plenary talks, panel discussions, invited sessions, oral sessions and poster sessions etc. for academic exchanges.

  • 2011 30th Chinese Control Conference (CCC)

    Systems and Control

  • 2010 29th Chinese Control Conference (CCC)

    S1 System Theory and Control Theory S2 Nonlinear Systems and Control S3 Complexity and Complex System Theory S4 Distributed Parameter Systems S5 Stability and Stabilization S6 Large Scale Systems S7 Stochastic Systems S8 System Modeling and System Identification S9 DEDS and Hybrid Systems S10 Optimal Control S11 Optimization and Scheduling S12 Robust Control S13 Adaptive Control and Learning Control S14 Variable Structure Control S15 Neural

  • 2008 Chinese Control Conference (CCC)

    The Chinese Control Conference (CCC) is an annual international conference organized by Tech. Com. on Control Theory, CAA. It provides a forum for scientists and engineers over the world to present their new theoretical results and techniques in the field of systems and control. The conference consists of plenary talks, panel discussions, oral and poster sessions etc. for academic exchanges. The conference proceedings have been selected for coverage in ISI proceedings/ISTP (Index to Scientific and Technical


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Periodicals related to Tomography

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Antennas and Wireless Propagation Letters, IEEE

IEEE Antennas and Wireless Propagation Letters (AWP Letters) will be devoted to the rapid electronic publication of short manuscripts in the technical areas of Antennas and Wireless Propagation.


Medical Imaging, IEEE Transactions on

Imaging methods applied to living organisms with emphasis on innovative approaches that use emerging technologies supported by rigorous physical and mathematical analysis and quantitative evaluation of performance.


Oceanic Engineering, IEEE Journal of

Bayes procedures; buried-object detection; dielectric measurements; Doppler measurements; geomagnetism; sea floor; sea ice; sea measurements; sea surface electromagnetic scattering; seismology; sonar; acoustic tomography; underwater acoustics; and underwater radio communication.


Proceedings of the IEEE

The most highly-cited general interest journal in electrical engineering and computer science, the Proceedings is the best way to stay informed on an exemplary range of topics. This journal also holds the distinction of having the longest useful archival life of any EE or computer related journal in the world! Since 1913, the Proceedings of the IEEE has been the ...


Selected Topics in Quantum Electronics, IEEE Journal of

40% devoted to special issues published in J. Quantum Electronics. Other topics: solid-state lasers, fiber lasers, optical diagnostics for semi-conductor manufacturing, and ultraviolet lasers and applications.


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Xplore Articles related to Tomography

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Moisture sensitivity and reliability of plastic thermally enhanced QFP packages

L. Yip Electronic Components and Technology Conference, 1994. Proceedings., 44th, 1994

Standard plastic quad flatpacks have difficulty meeting the thermal performance requirements of devices with high power dissipation. The development of plastic thermally enhanced quad flat Packs (TEQFP), which incorporate heat slugs or heat spreaders in the leadframes, provide a cost effective solution. Because the final packages are of molded plastic, TEQFP's are susceptible to moisture induced cracking and other plastic ...


Implementing high availability CORBA applications with Java

M. C. Little; S. K. Shrivastava Internet Applications, 1999. IEEE Workshop on, 1999

The integration of Java and CORBA has opened the way for a wide variety of Internet applications. However, such applications will frequently come across communication and node failures which can affect both their performance and consistency. Therefore, there is a need for techniques which will allow applications to tolerate such failures and continue to provide expected services. A common technique ...


Safety in medical signal analysis

A. F. Kohn; S. S. Furuie IEEE Engineering in Medicine and Biology Magazine, 1991

A number of issues are raised about the possibility of erroneous results obtained from signal analysis techniques that could lead to an incorrect diagnosis or an inadequate decision. An example is the use of a filter to attenuate interference when the (unidimensional) signal of interest contains wavelets. The output wavelets may be distorted by the filter in such a way ...


Functional Common-Path Fourier-domain OCT for hemoglobin oxygen saturation imaging

Jin U. Kang; Xuan Liu 2009 Asia Communications and Photonics conference and Exhibition (ACP), 2009

We propose and analyze functional Common-Path Fourier-domain Optical Coherence Tomography (CP-FDOCT) for providing localized and quantitative estimation of hemoglobin oxygen saturation (SO2) level in tissue. Result using a chicken embryo in vivo is presented.


Simulation of triple coincidences in PET

J. Cal-Gonzá lez; E. Herranz; E. Vicente; J. M. Udí as; S. R. Dave; V. Parot; E. Lage; J. L. Herraiz 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC), 2013

Most PET scanners are designed to detect and record gamma-ray coincidences from the annihilation of positrons coming from radiotracers. Multiple coincidences, those for which more than two gamma-rays are detected within the coincidence time window, are usually discarded. Those events can be registered and used to increase the sensitivity of the scanner and to differentiate positron-gamma emitters from pure positron ...


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Educational Resources on Tomography

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eLearning

Moisture sensitivity and reliability of plastic thermally enhanced QFP packages

L. Yip Electronic Components and Technology Conference, 1994. Proceedings., 44th, 1994

Standard plastic quad flatpacks have difficulty meeting the thermal performance requirements of devices with high power dissipation. The development of plastic thermally enhanced quad flat Packs (TEQFP), which incorporate heat slugs or heat spreaders in the leadframes, provide a cost effective solution. Because the final packages are of molded plastic, TEQFP's are susceptible to moisture induced cracking and other plastic ...


Implementing high availability CORBA applications with Java

M. C. Little; S. K. Shrivastava Internet Applications, 1999. IEEE Workshop on, 1999

The integration of Java and CORBA has opened the way for a wide variety of Internet applications. However, such applications will frequently come across communication and node failures which can affect both their performance and consistency. Therefore, there is a need for techniques which will allow applications to tolerate such failures and continue to provide expected services. A common technique ...


Safety in medical signal analysis

A. F. Kohn; S. S. Furuie IEEE Engineering in Medicine and Biology Magazine, 1991

A number of issues are raised about the possibility of erroneous results obtained from signal analysis techniques that could lead to an incorrect diagnosis or an inadequate decision. An example is the use of a filter to attenuate interference when the (unidimensional) signal of interest contains wavelets. The output wavelets may be distorted by the filter in such a way ...


Functional Common-Path Fourier-domain OCT for hemoglobin oxygen saturation imaging

Jin U. Kang; Xuan Liu 2009 Asia Communications and Photonics conference and Exhibition (ACP), 2009

We propose and analyze functional Common-Path Fourier-domain Optical Coherence Tomography (CP-FDOCT) for providing localized and quantitative estimation of hemoglobin oxygen saturation (SO2) level in tissue. Result using a chicken embryo in vivo is presented.


Simulation of triple coincidences in PET

J. Cal-Gonzá lez; E. Herranz; E. Vicente; J. M. Udí as; S. R. Dave; V. Parot; E. Lage; J. L. Herraiz 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC), 2013

Most PET scanners are designed to detect and record gamma-ray coincidences from the annihilation of positrons coming from radiotracers. Multiple coincidences, those for which more than two gamma-rays are detected within the coincidence time window, are usually discarded. Those events can be registered and used to increase the sensitivity of the scanner and to differentiate positron-gamma emitters from pure positron ...


More eLearning Resources

IEEE-USA E-Books

  • XRay Imaging and Computed Tomography

    This chapter contains sections titled: General Principles of Imaging with X-Rays X-Ray Production Interactions of X-Rays with Tissue Linear and Mass Attenuation Coefficients of X-Rays in Tissue Instrumentation for Planar X-Ray Imaging X-Ray Image Characteristics X-Ray Contrast Agents X-Ray Imaging Methods Clinical Applications of X-Ray Imaging Computed Tomography Image Processing for Computed Tomography Spiral/Helical Computed Tomography Multislice Spiral Computed Tomography Radiation Dose Clinical Applications of Computed Tomography This chapter contains sections titled: Exercises Further Reading

  • Nuclear Medicine

    This chapter contains sections titled: General Principles of Nuclear Medicine Radioactivity The Production of Radionuclides Types of Radioactive Decay The Technetium Generator The Biodistribution of Technetium-Based Agents within the Body Instrumentation: The Gamma Camera Image Characteristics Single Photon Emission Computed Tomography Clinical Applications of Nuclear Medicine Positron Emission Tomography This chapter contains sections titled: Exercises Further Reading

  • No title

    This book is a brief introduction to negative quantum channels, i.e., linear, trace-preserving (and consistent) quantum maps that are not completely positive. The flat and sharp operators are introduced and explained. Complete positivity is presented as a mathematical property, but it is argued that complete positivity is not a physical requirement of all quantum operations. Negativity, a measure of the lack of complete positivity, is proposed as a tool for empirically testing complete positivity assumptions. Table of Contents: Preface / Acknowledgments / Introduction and Definition of Terms / Tomography / Non-Positive Reduced Dynamics / Complete Positivity / Physical Motivation of Complete Positivity / Measures of Complete Positivity / Negative Channels / Negative Climates with Diagonal Composite Dynamics / Rabi Channels / Physical Motivations for Sharp Operations / Negative Qubit Channel Examples with Multi-Qubit Baths / Proposed Experimental Demonstration of Negativity / Implicatio s of Negative Channels / Uses for Negative Channels / Conclusions / Bibliography / Author's Biography

  • Index

    An integrated, comprehensive survey of biomedical imaging modalities An important component of the recent expansion in bioengineering is the area of biomedical imaging. This book provides in-depth coverage of the field of biomedical imaging, with particular attention to an engineering viewpoint. Suitable as both a professional reference and as a text for a one-semester course for biomedical engineers or medical technology students, Introduction to Biomedical Imaging covers the fundamentals and applications of four primary medical imaging techniques: magnetic resonance imaging, ultrasound, nuclear medicine, and X-ray/computed tomography. Taking an accessible approach that includes any necessary mathematics and transform methods, this book provides rigorous discussions of: The physical principles, instrumental design, data acquisition strategies, image reconstruction techniques, and clinical applications of each modality Recent developments such as multi-slice spiral computed tomography, harmonic and sub-harmonic ultrasonic imaging, multi-slice PET scanning, and functional magnetic resonance imaging General image characteristics such as spatial resolution and signal-to-noise, common to all of the imaging modalities

  • Three-Dimensional Diffraction Tomography

    The (first-order) Born approximation (BA) in 3D can be introduced in the same way as done in 2D, namely approximating the internal field with the incident one. It is important to outline that the spectral weight tends to zero all over the bound of the visible circle, so that the actual retrievable spectral set is never equal to the ideal one, in the sense that it would not be equal to the ideal set even if the measurement plane surface were unlimited, analogously to what happened in 2D. The spatial step and the transect or, in other terms, the spatial needed steps along the direction of the movement of the antennas and along the horizontal direction orthogonal to this are driven by the Nyquist criterion. In order to estimate the horizontal (and then the vertical) resolution, the same steps as implemented in the 2D case can be followed.

  • Electromyography-Driven Modeling for Simulating Subject-Specific Movement at the Neuromusculoskeletal Level

    This chapter provides a comprehensive description of subject-specific electromyography (EMG)-driven musculoskeletal models for the human lower extremity. EMG-driven modeling requires experimental human motion data to be captured for model calibration and operation. A musculoskeletal model is created from medical imaging data of bone and muscle surfaces, such as magnetic resonance imaging (MRI) or computed tomography. The multi-degrees of freedom (DOFs) model comprises five main components: musculotendon kinematics, musculotendon activation, musculotendon dynamics, moment computation, and model calibration. The chapter demonstrates the use of EMG-driven modeling to predict musculotendon units (MTUs) forces and the resulting joint moments about multiple DOFs during dynamic motor tasks. It outlines the use of EMG- driven modeling for applications in neurorehabilitation technologies. EMG- driven methodologies can be successfully applied to study dynamic tasks that involve muscle co-contraction. EMG-informed predictions of muscle forces acting on the hip have been also used to improve estimates of bone remodeling stimulus.

  • Diffraction Tomography

    There are several kinds of diffraction tomography (DT) relationships in relationship with the measurement configuration, but this chapter focuses on the common offset configuration. In general, a DT relationship requires more approximations than does the linearization provided by the BA. The effective maximum view angle is difficult to be predicted in a theoretical way, but in general it can be heuristically evaluated from the data. The chapter demonstrates the calculation of the available horizontal resolution, although the horizontal resolution cannot be separated from the vertical one, because the two quantities are correlated within the DT relationships. DT also provides an approximated but powerful tool to calculate the spatial step needed for taking GPR measurements correctly. The chapter also shows that GPR data can be processed either in the frequency domain or in the time domain.

  • Special Imaging Techniques

    This chapter contains sections titled: Acoustic Impedance Imaging - Impediography Elastography Tissue Speckle Tracking Through-Transmission Imaging Vibro-acoustic Imaging Time Reversal Ultrasonic Computed Tomography Contrast Materials Coded Excitations References

  • Ionospheric Tomography

    Proposals for tomographic-reconstruction techniques, using ?>differential Doppler?> data gained from the signals of polar-orbiting navigation satellites, began to appear around 1980. The reconstruction results are two- dimensional electron-density distributions, e.g., in height and geographic latitude. In mid- and high latitudes, the height range from about 200 to 600 km is covered; in the surroundings of the equatorial anomaly, the upper limit can be considerably higher. The horizontal range depends on the number and the spacing of the receiving stations. A typical range is 15 degrees. In recent years, several different reconstruction methods have been worked out. Some of them are have found practical application and are used in the production of two-dimensional electron-density profiles. All techniques suffer from the inherent problem that the data set available for the reconstruction is necessarily incomplete. Therefore, additional information has to be used, and it is not possible to select only one reconstruction method that should give the most plausible results under all conditions. Most of the reconstruction methods that have been published fall into the categories of ?>pixel?> methods (matrix reconstruction) or ?>model?> methods (fitting of model parameters). The main differences are found in the inversion techniques, and in the way a priori information about plausible electron- density distributions is incorporated. Incoherent-scatter radars can give the height dependence of electron density over the height range covered by ionosphere tomography. In general, such profiles are not available for the locations and observation times of satellite passes. The second-best way to gain additional information is the use of true height profiles from ionosondes, or, at least, the use of ionogram parameters. If no additional data exist from observations, one has to fall back to model considerations. (The large experience with ionospheric data and ionospheric physics that is now available allows filling in for missing information in a consistent way, and assessing the plausibility of the two- dimensional electron-density distributions from different reconstruction methods by inspecting the results.) The newest developments in observation possibilities allow one to overcome the inherent weakness of ground-based ionospheric tomography by using the global Navigation Satellite Systems (GNSS: the Global Positioning System, GPS, and/or its Russian equivalent, GLONASS), and reception of the navigation-beacon signals from satellites in low-Earth orbits. Shortly before Earth occultation of the signals, the rays connecting transmitters and receivers are nearly horizontal, and provide the information missing in ground-based tomography. Presently, one receiving satellite exists, and several more will be launched in the near future. Of course, the electron content along near-horizontal rays is only one part of the data system for tomographic reconstruction. It provides information about the average height distribution of ionization. Classical inversion techniques allow retrieval of just this information. Ground-based reception of satellite- beacon signals can provide complimentary information about the horizontal distribution of ionization. The old navigation systems are fading out, but their satellites in low polar orbits will continue to transmit signals for several years, and can provide the ground segment (high-elevation rays). Several other possibilities to gain and inco...

  • No title

    Representations are at the heart of artificial intelligence (AI). This book is devoted to the problem of representation discovery: how can an intelligent system construct representations from its experience? Representation discovery re-parameterizes the state space - prior to the application of information retrieval, machine learning, or optimization techniques - facilitating later inference processes by constructing new task-specific bases adapted to the state space geometry. This book presents a general approach to representation discovery using the framework of harmonic analysis, in particular Fourier and wavelet analysis. Biometric compression methods, the compact disc, the computerized axial tomography (CAT) scanner in medicine, JPEG compression, and spectral analysis of time-series data are among the many applications of classical Fourier and wavelet analysis. A central goal of this book is to show that these analytical tools can be generalized from their usual setting in (infin te-dimensional) Euclidean spaces to discrete (finite-dimensional) spaces typically studied in many subfields of AI. Generalizing harmonic analysis to discrete spaces poses many challenges: a discrete representation of the space must be adaptively acquired; basis functions are not pre-defined, but rather must be constructed. Algorithms for efficiently computing and representing bases require dealing with the curse of dimensionality. However, the benefits can outweigh the costs, since the extracted basis functions outperform parametric bases as they often reflect the irregular shape of a particular state space. Case studies from computer graphics, information retrieval, machine learning, and state space planning are used to illustrate the benefits of the proposed framework, and the challenges that remain to be addressed. Representation discovery is an actively developing field, and the author hopes this book will encourage other researchers to explore this exciting area of research. Tab e of Contents: Overview / Vector Spaces / Fourier Bases on Graphs / Multiscale Bases on Graphs / Scaling to Large Spaces / Case Study: State-Space Planning / Case Study: Computer Graphics / Case Study: Natural Language / Future Directions



Standards related to Tomography

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No standards are currently tagged "Tomography"