WorldWideScience

Sample records for astronomy receiver systems

  1. Radio Astronomy Software Defined Receiver Project

    Energy Technology Data Exchange (ETDEWEB)

    Vacaliuc, Bogdan [ORNL; Leech, Marcus [Shirleys Bay Radio Astronomy Consortium; Oxley, Paul [Retired; Flagg, Richard [Retired; Fields, David [ORNL

    2011-01-01

    The paper describes a Radio Astronomy Software Defined Receiver (RASDR) that is currently under development. RASDR is targeted for use by amateurs and small institutions where cost is a primary consideration. The receiver will operate from HF thru 2.8 GHz. Front-end components such as preamps, block down-converters and pre-select bandpass filters are outside the scope of this development and will be provided by the user. The receiver includes RF amplifiers and attenuators, synthesized LOs, quadrature down converters, dual 8 bit ADCs and a Signal Processor that provides firmware processing of the digital bit stream. RASDR will interface to a user s PC via a USB or higher speed Ethernet LAN connection. The PC will run software that provides processing of the bit stream, a graphical user interface, as well as data analysis and storage. Software should support MAC OS, Windows and Linux platforms and will focus on such radio astronomy applications as total power measurements, pulsar detection, and spectral line studies.

  2. Planetary radio astronomy receiver. [experiment on Voyager spacecraft

    Science.gov (United States)

    Lang, G. J.; Peltzer, R. G.

    1977-01-01

    The planetary radio astronomy (PRA) experiment on the Voyager spacecraft will measure the amplitude, spectrum, time variations, and polarization of radio emissions over a frequency range of 1.2 kHz to 40.5 MHz with the aid of the PRA receiver (PRAR) and two 10-m orthogonal monopoles. Sensitivity and dynamic range will allow observation of a wide range of Jovian emissions from near earth to encounter. This paper describes the system elements, including the preamp/attenuator/calibrator, the LF polarization discriminator, the four LF-IF amplifier stages, the HF polarization discriminator, the translation LO, the log-IF and detector, the frequency synthesizer, the data processor, control system, power supply, and antennas.

  3. 47 CFR 73.6027 - Class A TV notifications concerning interference to radio astronomy, research and receiving...

    Science.gov (United States)

    2010-10-01

    ... interference to radio astronomy, research and receiving installations. 73.6027 Section 73.6027... radio astronomy, research and receiving installations. An applicant for digital operation of an existing... astronomy, research and receiving installations....

  4. Electronic warfare receivers and receiving systems

    CERN Document Server

    Poisel, Richard A

    2014-01-01

    Receivers systems are considered the core of electronic warfare (EW) intercept systems. Without them, the fundamental purpose of such systems is null and void. This book considers the major elements that make up receiver systems and the receivers that go in them.This resource provides system design engineers with techniques for design and development of EW receivers for modern modulations (spread spectrum) in addition to receivers for older, common modulation formats. Each major module in these receivers is considered in detail. Design information is included as well as performance tradeoffs o

  5. A 492 GHz cooled Schottky receiver for radio-astronomy

    Science.gov (United States)

    Hernichel, J.; Schieder, R.; Stutzki, J.; Vowinkel, B.; Winnewisser, G.; Zimmermann, Peter

    1992-01-01

    We developed a 492 GHz cooled GaAs Schottky receiver driven by a solid state local oscillator with a DSB noise temperature of 550 K measured at the telescope. The receiver-bandwidth is approx. equal to 1.0 GHz. Quasi-optical mirrors focus the sky and local oscillator radiation into the mixer. Stability analysis via the Allan variance method shows that the total system including a 1 GHz bandwidth acousto-optical spectrometer built in Cologne allows integration times up to 100 sec per half switching cycle. We successfully used the receiver at the KOSMA 3 m telescope on Gornergrat (3150m) located in the central Swiss Alps near Zermatt during January-February 1992 for observations of the 492 GHz, (CI) (3)P1 to (3)P0 fine structure line in several galactic sources. These observations confirm that Gornergrat is an excellent winter submillimeter site in accordance with previous predictions based on the atmospheric opacity from KOSMA 345 GHz measurements.

  6. Electromagnetic Techniques for Analysis and Design of Ultra Sensitive Receivers for Far-Infrared Astronomy

    OpenAIRE

    Bracken, Colm

    2015-01-01

    This thesis focuses on EM (electromagnetic) modelling methods for simulating the behaviour of receivers and detectors for far-IR (far-infrared) astronomy and CMB (cosmic microwave background) applications, toward an optimum design for SAFARI (the Spica Far-Infrared Instrument) on the proposed space based telescope SPICA (Space Infrared Telescope for Cosmology and Astrophysics). The computational methods required for modelling SAFARI-like receivers are described, and sophisti...

  7. Astronomy

    CERN Document Server

    Seymour, Percy

    2014-01-01

    With a blend of exciting discoveries and important scientific theory,this innovative and readable introduction to astronomy is ideal for anyone who wants to understand what we know about the universe,and how we know it. Each chapter starts with details of a method of jow astronomers over time have observed the world,and then uses this as a springboard to discuss what they discovered,and why this was important for understanding the cosmos. The last chapter,on dark matter,also focuses on the many things we don''t yet know - reminding us that astronomy,like this book,is a fast-paced and fascinati

  8. The solar system in modern astronomy

    International Nuclear Information System (INIS)

    This invited conference lecture opens with a discussion of the importance of studies of the solar system in their contribution to the more general areas of astronomy and astrophysics. Most of the paper is devoted to a review of present knowledge of the Moon and its early history. The author discusses at some length the paleontological evidence, from the analysis of lunar rocks and from magnetometer recordings made during flights of lunar orbiting satellites, for the existence of an ancient dipole magnetic field generated by a core-dynamo process, similar to that of the Earth. Mapping of the intensities and directions of the paleomagnetic fields is also discussed, leading to estimates of the age and decay-rate of the ancient field. (U.K.)

  9. Solar system radio astronomy at low frequencies

    Science.gov (United States)

    Desch, M. D.

    1987-01-01

    The planetary radio-astronomy observations obtained with the two Voyager spacecraft since their launch in 1977 are briefly characterized and illustrated with graphs, diagrams, and sample spectra. Topics addressed include the spacecraft designs and trajectories, the wavelength coverage of the radio instruments, the Io-controlled LF emission of Jupiter, the solar-wind effect on the Saturn kilometric radiation, the Saturn electrostatic discharges, and the use of the clocklike feature of the Uranus emission to measure the planet's rotation period.

  10. Low noise, 0.4-3 GHz cryogenic receiver for radio astronomy.

    Science.gov (United States)

    Gawande, R; Bradley, R; Langston, G

    2014-10-01

    We present the design and measurement of a radio telescope receiver front end cooled to 100 K physical temperature, and working over 400 MHz to 3 GHz frequency band. The system uses a frequency independent feed developed for operation as a feed for parabola using sinuous elements and integrated with an ultra-wideband low noise amplifier. The ambient temperature system is tested on the 43 m radio telescope in Green Bank, WV and the system verification results on the sky are presented. The cryogenic receiver is developed using a Stirling cycle, one stage cryocooler. The measured far field patterns and the system noise less than 80 K over a 5:1 bandwidth are presented. PMID:25362437

  11. Low noise, 0.4-3 GHz cryogenic receiver for radio astronomy.

    Science.gov (United States)

    Gawande, R; Bradley, R; Langston, G

    2014-10-01

    We present the design and measurement of a radio telescope receiver front end cooled to 100 K physical temperature, and working over 400 MHz to 3 GHz frequency band. The system uses a frequency independent feed developed for operation as a feed for parabola using sinuous elements and integrated with an ultra-wideband low noise amplifier. The ambient temperature system is tested on the 43 m radio telescope in Green Bank, WV and the system verification results on the sky are presented. The cryogenic receiver is developed using a Stirling cycle, one stage cryocooler. The measured far field patterns and the system noise less than 80 K over a 5:1 bandwidth are presented.

  12. The Submillimeter Wave Astronomy Satellite (SWAS) solar array system

    Science.gov (United States)

    Sneiderman, Gary

    1993-01-01

    The SWAS (Submillimeter Wave Astronomy Satellite) solar array system is described. It is an innovative approach to meet the missions requirements. The SWAS satellite provides a three axis stabilized platform to survey a variety of galactic cloud structures. This system includes highly reliable, lightweight launch latch, deployment, and lock mechanisms, and solar array panels that provide the maximum solar cell area. The design of the solar arrays are the result of system trades that included instrument and spacecraft thermal constraints, attitude control system maneuvering rates and pointing accuracies, the power system, and the spacecraft structure.

  13. First supra-THz Heterodyne Array Receivers for Astronomy with the SOFIA Observatory

    CERN Document Server

    Risacher, Christophe; Stutzki, Juergen; Huebers, Heinz-Wilhelm; Buechel, Denis; Graf, Urs U; Heyminck, Stefan; Honingh, Cornelia E; Jacobs, Karl; Klein, Bernd; Klein, Thomas; Leinz, Christian; Puetz, Patrick; Reyes, Nicolas; Ricken, Oliver; Wunsch, Hans-Joachim; Fusco, Paul; Rosner, Stefan

    2015-01-01

    We present the upGREAT THz heterodyne arrays for far-infrared astronomy. The Low Frequency Array (LFA) is designed to cover the 1.9-2.5 THz range using 2x7-pixel waveguide-based HEB mixer arrays in a dual polarization configuration. The High Frequency Array (HFA) will perform observations of the [OI] line at ~4.745 THz using a 7-pixel waveguide-based HEB mixer array. This paper describes the common design for both arrays, cooled to 4.5 K using closed- cycle pulse tube technology. We then show the laboratory and telescope characterization of the first array with its 14 pixels (LFA), which culminated in the successful commissioning in May 2015 aboard the SOFIA airborne observatory observing the [CII] fine structure transition at 1.905 THz. This is the first successful demonstration of astronomical observations with a heterodyne focal plane array above 1 THz and is also the first time high- power closed-cycle coolers for temperatures below 4.5 K are operated on an airborne platform.

  14. CCD image data acquisition system for optical astronomy.

    Science.gov (United States)

    Bhat, P. N.; Patnaik, K.; Kembhavi, A. K.; Patnaik, A. R.; Prabhu, T. P.

    1990-11-01

    A complete image processing system based on a charge coupled device (CCD) has been developed at TIFR, Bombay, for use in optical astronomy. The system consists of a P-8600/B GEC CCD chip, a CCD controller, a VAX 11/725 mini-computer to carry out the image acquisition and display on a VS-11 monitor. All the necessary software and part of the hardware were developed locally, integrated together and installed at the Vainu Bappu Observatory at Kavalur. CCD as an imaging device and its advantages over the conventional photographic plate is briefly reviewed. The acquisition system is described in detail. The preliminary results are presented and the future research programme is outlined.

  15. Simple nonlinearity evaluation and modeling of low-noise amplifiers with application to radio astronomy receivers.

    Science.gov (United States)

    Casas, F J; Pascual, J P; de la Fuente, M L; Artal, E; Portilla, J

    2010-07-01

    This paper describes a comparative nonlinear analysis of low-noise amplifiers (LNAs) under different stimuli for use in astronomical applications. Wide-band Gaussian-noise input signals, together with the high values of gain required, make that figures of merit, such as the 1 dB compression (1 dBc) point of amplifiers, become crucial in the design process of radiometric receivers in order to guarantee the linearity in their nominal operation. The typical method to obtain the 1 dBc point is by using single-tone excitation signals to get the nonlinear amplitude to amplitude (AM-AM) characteristic but, as will be shown in the paper, in radiometers, the nature of the wide-band Gaussian-noise excitation signals makes the amplifiers present higher nonlinearity than when using single tone excitation signals. Therefore, in order to analyze the suitability of the LNA's nominal operation, the 1 dBc point has to be obtained, but using realistic excitation signals. In this work, an analytical study of compression effects in amplifiers due to excitation signals composed of several tones is reported. Moreover, LNA nonlinear characteristics, as AM-AM, total distortion, and power to distortion ratio, have been obtained by simulation and measurement with wide-band Gaussian-noise excitation signals. This kind of signal can be considered as a limit case of a multitone signal, when the number of tones is very high. The work is illustrated by means of the extraction of realistic nonlinear characteristics, through simulation and measurement, of a 31 GHz back-end module LNA used in the radiometer of the QUIJOTE (Q U I JOint TEnerife) CMB experiment. PMID:20687750

  16. Simple nonlinearity evaluation and modeling of low-noise amplifiers with application to radio astronomy receivers.

    Science.gov (United States)

    Casas, F J; Pascual, J P; de la Fuente, M L; Artal, E; Portilla, J

    2010-07-01

    This paper describes a comparative nonlinear analysis of low-noise amplifiers (LNAs) under different stimuli for use in astronomical applications. Wide-band Gaussian-noise input signals, together with the high values of gain required, make that figures of merit, such as the 1 dB compression (1 dBc) point of amplifiers, become crucial in the design process of radiometric receivers in order to guarantee the linearity in their nominal operation. The typical method to obtain the 1 dBc point is by using single-tone excitation signals to get the nonlinear amplitude to amplitude (AM-AM) characteristic but, as will be shown in the paper, in radiometers, the nature of the wide-band Gaussian-noise excitation signals makes the amplifiers present higher nonlinearity than when using single tone excitation signals. Therefore, in order to analyze the suitability of the LNA's nominal operation, the 1 dBc point has to be obtained, but using realistic excitation signals. In this work, an analytical study of compression effects in amplifiers due to excitation signals composed of several tones is reported. Moreover, LNA nonlinear characteristics, as AM-AM, total distortion, and power to distortion ratio, have been obtained by simulation and measurement with wide-band Gaussian-noise excitation signals. This kind of signal can be considered as a limit case of a multitone signal, when the number of tones is very high. The work is illustrated by means of the extraction of realistic nonlinear characteristics, through simulation and measurement, of a 31 GHz back-end module LNA used in the radiometer of the QUIJOTE (Q U I JOint TEnerife) CMB experiment.

  17. Image data-processing system for solar astronomy

    Science.gov (United States)

    Wilson, R. M.; Teuber, D. L.; Watkins, J. R.; Thomas, D. T.; Cooper, C. M.

    1977-01-01

    The paper describes an image data processing system (IDAPS), its hardware/software configuration, and interactive and batch modes of operation for the analysis of the Skylab/Apollo Telescope Mount S056 X-Ray Telescope experiment data. Interactive IDAPS is primarily designed to provide on-line interactive user control of image processing operations for image familiarization, sequence and parameter optimization, and selective feature extraction and analysis. Batch IDAPS follows the normal conventions of card control and data input and output, and is best suited where the desired parameters and sequence of operations are known and when long image-processing times are required. Particular attention is given to the way in which this system has been used in solar astronomy and other investigations. Some recent results obtained by means of IDAPS are presented.

  18. Photographs and Classroom Response Systems in Middle School Astronomy Classes

    Science.gov (United States)

    Lee, Hyunju; Feldman, Allan

    2015-08-01

    In spite of being readily available, photographs have played a minor and passive role in science classes. In our study, we present an active way of using photographs in classroom discussions with the use of a classroom response system (CRS) in middle school astronomy classes to teach the concepts of day-night and seasonal change. In this new pedagogical method, students observe objects or phenomena in photographs and use the information to develop understanding of the scientific concepts. They share their ideas in classroom discussion with the assistance of the CRS. Pre- and posttest results showed that the new pedagogy helped students overcome primitive conceptions and enhanced their understanding of the concepts. The observation of the rich details of photographs played three pedagogical roles in classroom discussion: easing students' anxiety about learning a new scientific concept; continuous stimulus of learning; and as evidence or data.

  19. ITERATIVE RECEIVER FOR OFDM-SDMA SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Shan Shuwei; Luo Hanwen; Song Wentao

    2004-01-01

    An iterative receiver is proposed based on the EM (Expectation-Maximization)algorithm for an OFDM-SDMA (Orthogonal Frequency Division Multiplexing-Space Division Multiple Access) system. By using a few pilots in every OFDM symbol, both channel estimation and multiuser detection can be simultaneously obtained by iteration. The computer simulation results show this receiver can track channel variations and detect multiuser symbols for different number of users under time-varying multipath channels.

  20. CANFAR+Skytree: A Cloud Computing and Data Mining System for Astronomy

    OpenAIRE

    Ball, Nicholas M.

    2013-01-01

    At the Canadian Astronomy Data Centre, we have combined our cloud computing system, CANFAR, with the world's most advanced machine learning software, Skytree, to create the world's first cloud computing system for data mining in astronomy. CANFAR provides a generic environment for the storage and processing of large datasets, removing the requirement to set up and maintain a computing system when implementing an extensive undertaking such as a survey pipeline. 500 processor cores and several ...

  1. A Multi-Feed Receiver in the 18 to 26.5 GHz Band for Radio Astronomy

    Science.gov (United States)

    Orfei, A.; Carbonaro, L.; Cattani, A.; Cremonini, A.; Cresci, L.; Fiocchi, F.; Maccaferri, A.; Maccaferri, G.; Mariotti, S.; Monari, J.; Morsiani, M.; Natale, V.; Nesti, R.; Panella, D.; Poloni, M.; Roda, J.; Scalambra, A.; Tofani, G.

    2010-08-01

    A large-bandwidth, state-of-the-art multi-feed receiver has been constructed to be used on the new 64 m Sardinia Radio Telescope (SRT) (http://www.srt.inaf.itl), an antenna aiming to work from 300 MHz to 100 GHz with an almost continuous frequency coverage. The goal of this new receiver is to speed up the survey of the sky with high sensitivity in a frequency band that is very interesting to radio astronomers. In the meantime, the antenna erection has been finalized, and the receiver has been mounted on the Medicina 32 m antenna to be tested (http://www.med.ira.inaf.itl). We present a complete description of the system, including a dedicated backend, and the results of the tests.

  2. PADMINI: A PEER-TO-PEER DISTRIBUTED ASTRONOMY DATA MINING SYSTEM AND A CASE STUDY

    Data.gov (United States)

    National Aeronautics and Space Administration — PADMINI: A PEER-TO-PEER DISTRIBUTED ASTRONOMY DATA MINING SYSTEM AND A CASE STUDY TUSHAR MAHULE*, KIRK BORNE, SANDIPAN DEY*, SUGANDHA ARORA, AND HILLOL KARGUPTA...

  3. News Conference: Bloodhound races into history Competition: School launches weather balloon Course: Update weekends inspire teachers Conference: Finland hosts GIREP conference Astronomy: AstroSchools sets up schools network to share astronomy knowledge Teaching: Delegates praise science events in Wales Resources: ELI goes from strength to strength International: South Sudan teachers receive training Workshop: Delegates experience universality

    Science.gov (United States)

    2011-11-01

    Conference: Bloodhound races into history Competition: School launches weather balloon Course: Update weekends inspire teachers Conference: Finland hosts GIREP conference Astronomy: AstroSchools sets up schools network to share astronomy knowledge Teaching: Delegates praise science events in Wales Resources: ELI goes from strength to strength International: South Sudan teachers receive training Workshop: Delegates experience universality

  4. SKA antenna systems; Outlook for non-astronomy applications

    NARCIS (Netherlands)

    Ardenne, van A.; Bentum, M.J.; Boonstra, A.J.

    2012-01-01

    The globally endorsed Square Kilometre Array project primarily aims to advance high sensitivity radio astronomy using a distributed collection of radio telescope stations spiraling outward from the core along three to five arms out to 3000km. This planned highly sensitive instrument covering a frequ

  5. SKA antenna systems; outlook for non-astronomy applications

    NARCIS (Netherlands)

    Ardenne, van A.; Bentum, M.J.; Boonstra, A.J.

    2011-01-01

    The globally endorsed Square Kilometre Array project primarily aims to advance high sensitivity radio astronomy using a distributed collection of radio telescope stations spiraling outward from the core along three to five arms out to 3000km. This planned highly sensitive instrument covering a frequ

  6. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2013-01-01

    This 6th edition of “Tools of Radio Astronomy”, the most used introductory text in radio astronomy, has been revised to reflect the current state of this important branch of astronomy. This includes the use of satellites, low radio frequencies, the millimeter/sub-mm universe, the Cosmic Microwave Background and the increased importance of mm/sub-mm dust emission. Several derivations and presentations of technical aspects of radio astronomy and receivers, such as receiver noise, the Hertz dipole and  beam forming have been updated, expanded, re-worked or complemented by alternative derivations. These reflect advances in technology. The wider bandwidths of the Jansky-VLA and long wave arrays such as LOFAR and mm/sub-mm arrays such as ALMA required an expansion of the discussion of interferometers and aperture synthesis. Developments in data reduction algorithms have been included. As a result of the large amount of data collected in the past 20 years, the discussion of solar system radio astronomy, dust em...

  7. Solar receiver performance of point focusing collector system

    Science.gov (United States)

    Wu, Y. C.; Wen, L. C.

    1978-01-01

    The solar receiver performance of cavity receivers and external receivers used in dispersed solar power systems was evaluated for the temperature range 300-1300 C. Several parameters of receiver and concentrator are examined. It was found that cavity receivers are generally more efficient than external receivers, especially at high temperatures which require a large heat transfer area. The effects of variation in the ratio of receiver area to aperture area are considered.

  8. CANFAR+Skytree: A Cloud Computing and Data Mining System for Astronomy

    CERN Document Server

    Ball, Nicholas M

    2013-01-01

    At the Canadian Astronomy Data Centre, we have combined our cloud computing system, CANFAR, with the world's most advanced machine learning software, Skytree, to create the world's first cloud computing system for data mining in astronomy. CANFAR provides a generic environment for the storage and processing of large datasets, removing the requirement to set up and maintain a computing system when implementing an extensive undertaking such as a survey pipeline. 500 processor cores and several hundred terabytes of persistent storage are currently available to users. The storage is implemented via the International Virtual Observatory Alliance's VOSpace protocol, and is accessible both interactively, and to all processing jobs. The user interacts with CANFAR by utilizing virtual machines, which appear to them as equivalent to a desktop. Each machine is replicated as desired to perform large-scale parallel processing. Such an arrangement enables the user to immediately install and run the same astronomy code that...

  9. Astronomy essentials

    CERN Document Server

    Brass, Charles O

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Astronomy includes the historical perspective of astronomy, sky basics and the celestial coordinate systems, a model and the origin of the solar system, the sun, the planets, Kepler'

  10. Focus Demo: CANFAR+Skytree: A Cloud Computing and Data Mining System for Astronomy

    OpenAIRE

    Ball, Nicholas M.

    2013-01-01

    Comment: 4 pages, 2 figures, uses asp2010.sty. Written when at National Research Council Canada. Now at Skytree, Inc., San Jose, CA, USA. There is a companion paper: "CANFAR+Skytree: A Cloud Computing and Data Mining System for Astronomy". Astronomical Data Analysis Software & Systems (ADASS) XXII, 2012, ASP Conference Proceedings, eds. Friedel D., Freemon M., Plante R. (San Francisco: ASP)

  11. Waste receiving and processing plant control system; system design description

    International Nuclear Information System (INIS)

    The Plant Control System (PCS) is a heterogeneous computer system composed of numerous sub-systems. The PCS represents every major computer system that is used to support operation of the Waste Receiving and Processing (WRAP) facility. This document, the System Design Description (PCS SDD), includes several chapters and appendices. Each chapter is devoted to a separate PCS sub-system. Typically, each chapter includes an overview description of the system, a list of associated documents related to operation of that system, and a detailed description of relevant system features. Each appendice provides configuration information for selected PCS sub-systems. The appendices are designed as separate sections to assist in maintaining this document due to frequent changes in system configurations. This document is intended to serve as the primary reference for configuration of PCS computer systems. The use of this document is further described in the WRAP System Configuration Management Plan, WMH-350, Section 4.1

  12. Waste receiving and processing plant control system; system design description

    Energy Technology Data Exchange (ETDEWEB)

    LANE, M.P.

    1999-02-24

    The Plant Control System (PCS) is a heterogeneous computer system composed of numerous sub-systems. The PCS represents every major computer system that is used to support operation of the Waste Receiving and Processing (WRAP) facility. This document, the System Design Description (PCS SDD), includes several chapters and appendices. Each chapter is devoted to a separate PCS sub-system. Typically, each chapter includes an overview description of the system, a list of associated documents related to operation of that system, and a detailed description of relevant system features. Each appendice provides configuration information for selected PCS sub-systems. The appendices are designed as separate sections to assist in maintaining this document due to frequent changes in system configurations. This document is intended to serve as the primary reference for configuration of PCS computer systems. The use of this document is further described in the WRAP System Configuration Management Plan, WMH-350, Section 4.1.

  13. Different Reward Structures to Motivate Student Interaction with Electronic Response Systems in Astronomy

    Science.gov (United States)

    Len, Patrick M.

    2007-01-01

    Electronic response systems ("clickers") are used in introductory astronomy classes as a real-time assessment tool. Different reward structures for student responses to clicker questions are used to motivate individual participation or group collaboration before responding. The impact of two reward structures on student behavior and learning is…

  14. Radio astronomy

    International Nuclear Information System (INIS)

    This report highlights radio astronomy research of the 40th IAU commission in the years 1982-1984. Radio imaging of different objects are treated in separate sections: solar system, galaxy, supernovae, extragalactic objects. The paper begins with a section on radio instrumentation

  15. 7 CFR 400.209 - Electronic transmission and receiving system.

    Science.gov (United States)

    2010-01-01

    ... Contract-Standards for Approval § 400.209 Electronic transmission and receiving system. Any Contractor under the Contract is required to: (a) Adopt a plan for the purpose of transmitting and receiving... 7 Agriculture 6 2010-01-01 2010-01-01 false Electronic transmission and receiving system....

  16. Development of Student Exercises with Instructor Support at the Astronomy Workshop Solar System Collisions Web Tool

    Science.gov (United States)

    Deming, G. L.; Hamilton, D. P.

    2005-12-01

    During the spring 2005 semester, seven students taking ASTR101 General Astronomy for non-science majors at the University of Maryland were interviewed while completing an assignment using the Astronomy Workshop Solar System Collisions web tool (http://janus.umd.edu/astro/impact/). The Astronomy Workshop Solar System Collisions web tool can be used to investigate how different variables affect collisions in a fun, but informative manner. Based on the 2005 spring interviews, three web-based activities were developed as appropriate for homework or as enrichment to coursework. The first activity explores how the impactor's mass affects energy released, crater diameter, frequency of similar impacts, and magnitude of the earthquake generated by the impact. The second activity investigates the energy released and damage done when the impactor's density is changed. Collisions by icy bodies are compared to those of rocky and metallic materials. The third activity compares collisions on different planets. In addition to masses and densities, velocities vary in these collisions. The activities are written so that introductory astronomy students will interpret the differences observed in terms of kinetic energy. During the fall 2005 semester, ASTR101 students at the University of Maryland were interviewed and observed as they completed the three activities described above using the Solar System Collisions website. The twelve students in this study were selected based on pretest scores on the Astronomy Diagnostic Test. An effort was made to include students of diverse backgrounds and mathematical experiences. Based on these interviews, final revisions have been made. Student exercises on the website and the directions on how instructors can use these materials in their courses are ready for field-testing at other institutions. Faculty interested in participating in the field-test for this project during spring 2006 are encouraged to contact the authors. This research is funded

  17. Effects of the Number of Active Receiver Channels on the Sensitivity of a Reflector Antenna System with a Multi-Beam Wideband Phased Array Feed

    CERN Document Server

    Iupikov, O

    2016-01-01

    A method for accurate modeling of a reflector antenna system with a wideband phased array feed is presented and used to study the effects of the number of active antenna elements and associated receiving channels on the receiving sensitivity of the antenna system. Numerical results are shown for a practical design named APERTIF that is currently under developed at The Netherlands Institute for Radio Astronomy (ASTRON).

  18. Workshop on Satellite Power Systems (SPS) effects on optical and radio astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Stokes, G.M.; Ekstrom, P.A. (eds.)

    1980-04-01

    The impacts of the SPS on astronomy were concluded to be: increased sky brightness, reducing the effective aperture of terrestrial telescopes; microwave leakage radiation causing erroneous radioastronomical signals; direct overload of radioastronomical receivers at centimeter wavelengths; and unintentional radio emissions associated with massive amounts of microwave power or with the presence of large, warm structures in orbit causing the satellites to appear as individual stationary radio sources; finally, the fixed location of the geostationary satellite orbits would result in fixed regions of the sky being unusable for observations. (GHT)

  19. Workshop on Satellite Power Systems (SPS) effects on optical and radio astronomy

    International Nuclear Information System (INIS)

    The impacts of the SPS on astronomy were concluded to be: increased sky brightness, reducing the effective aperture of terrestrial telescopes; microwave leakage radiation causing erroneous radioastronomical signals; direct overload of radioastronomical receivers at centimeter wavelengths; and unintentional radio emissions associated with massive amounts of microwave power or with the presence of large, warm structures in orbit causing the satellites to appear as individual stationary radio sources; finally, the fixed location of the geostationary satellite orbits would result in fixed regions of the sky being unusable for observations

  20. A pseudolite-based positioning system for legacy GNSS receivers.

    Science.gov (United States)

    Kim, Chongwon; So, Hyoungmin; Lee, Taikjin; Kee, Changdon

    2014-03-27

    The ephemeris data format of legacy GPS receivers is improper for positioning stationary pseudolites on the ground. Therefore, to utilize pseudolites for navigation, GPS receivers must be modified so that they can handle the modified data formats of the pseudolites. Because of this problem, the practical use of pseudolites has so far been limited. This paper proposes a pseudolite-based positioning system that can be used with unmodified legacy GPS receivers. In the proposed system, pseudolites transmit simulated GPS signals. The signals use standard GPS ephemeris data format and contain ephemeris data of simulated GPS satellites, not those of pseudolites. The use of the standard format enables the GPS receiver to process pseudolite signals without any modification. However, the position output of the GPS receiver is not the correct position in this system, because there are additional signal delays from each pseudolite to the receiver. A post-calculation process was added to obtain the correct receiver position using GPS receiver output. This re-estimation is possible because it is based on known information about the simulated signals, pseudolites, and positioning process of the GPS receiver. Simulations using generated data and live GPS data are conducted for various geometries to verify the proposed system. The test results show that the proposed system provides the desired user position using pseudolite signals without requiring any modifications to the legacy GPS receiver. In this initial study, a pseudolite-only indoor system was assumed. However, it can be expanded to a GPS-pseudolite system outdoors.

  1. Joint Transmitter-Receiver Optimization in the Downlink CDMA Systems

    Directory of Open Access Journals (Sweden)

    Mohammad Saquib

    2002-08-01

    Full Text Available To maximize the downlink code-division multiple access (CDMA system capacity, we propose to minimize the total transmitted power of the system subject to users′ signal-to-interference ratio (SIR requirements via designing optimum transmitter sequences and utilizing linear optimum receivers (minimum mean square error (MMSE receiver. In our work on joint transmitter-receiver design for the downlink CDMA systems with multiple antennas and multipath channels, we develop several optimization algorithms by considering various system constraints and prove their convergence. We empirically observed that under the optimization algorithm with no constraint on the system, the optimum receiver structure matches the received transmitter sequences. A simulation study is performed to see how the different practical system constraints penalize the system with respect to the optimum algorithm with no constraint on the system.

  2. The New Physics and Astronomy Education Portal of the Smithsonian/NASA Astrophysics Data System

    Science.gov (United States)

    Kurtz, Michael J.; Eichhorn, G.; Accomazzi, A.; Grant, C.; Henneken, E.; Thompson, D.; Bohlen, E.; Murray, S. S.

    2006-12-01

    The ADS announces the beta release of a new portal into the technical literature for physics and astronomy education. This project is being done in collaboration with ComPADRE. Currently the collection contains about 30,000 articles covering the Science Education literature; key journals in the collection include Research in Science Education, Physical Review Special Topics Physics Education Research, The Physics Teacher, The American Journal of Physics, Physics Education, Journal of Research in Science Teaching, The International Journal of Science Education. Several other journals are also included, including some from nearby fields, such as computer science and chemistry education. The system easily has the ability to include any individual article from the research literature of physics and astronomy (such as from the Physical Review or the Astrophysical Journal) either from current or historical research. We encourage educators to suggest such articles to us. This is the beta release of a new system; we encourage comments, critisms and suggestions.

  3. System integration and radiation pattern measurements of a phased array antenna employing an integrated photonic beamformer for radio astronomy applications.

    Science.gov (United States)

    Burla, Maurizio; Roeloffzen, Chris G H; Zhuang, Leimeng; Marpaung, David; Khan, Muhammad Rezaul; Maat, Peter; Dijkstra, Klaas; Leinse, Arne; Hoekman, Marcel; Heideman, René

    2012-03-01

    In this paper we describe the system integration and the experimental demonstration of a photonically beamformed four-element receiving array antenna for radio astronomy applications. To our knowledge, the work described here is the first demonstration of the squint-free, continuously tunable beamsteering capability offered by an integrated photonic beamformer based on optical ring resonator true-time-delay units, with measured radiation patterns. The integrated beamformer is realized in a low loss, complementary metal-oxide-semiconductor (CMOS) compatible optical waveguide technology. The measurements show a wideband, continuous beamsteering operation over a steering angle of 23.5 degrees and an instantaneous bandwidth of 500 MHz limited only by the measurement setup. PMID:22410879

  4. A Friendly Command, Control, and Information System for Astronomy

    Science.gov (United States)

    McGraw, John T.; Duric, Nebojsa; Sjulin, Michael; Slezak, Scott; Westpfahl, David

    Virtually real user interfaces and device independent communications systems provide a robust, secure and efficient means for remote control of telescopes, data transfer, and interaction among personnel at distant sites. A variety of techniques has been implemented for remote operation of telescopes. This paper describes a new system incorporating secured, compacted, simultaneous information transfer of multiple data types, robust command structure and a user interface which pre-tests commands for security. Testing is accomplished by manipulating and displaying planned allowable motions using a virtual telescope and instrument before real hardware executes the desired motions. Embedded in this system is the ability to create efficient interfaces for all classes of users, data and system security, error correction and multiple forms of data compression. The system results from a merger of a military command and control system and a control system for robots operating in hazardous environments. Both systems were developed by Sandia National Laboratories. The merged system is proposed to enable elementary school children to access remotely operable telescopes and other assets of the LodeStar Project, which provides science education and research capability throughout New Mexico. The definition and constraints on the system are appropriate for its use by the professional astronomical community, as well, perhaps as a standard control and communications system supported, in part, within the national laboratories. In this paper we discuss implementation of the prototype system, its features, and its constraints, particularly with respect to bandwidth limitations.

  5. A Desktop Virtual Reality Earth Motion System in Astronomy Education

    Science.gov (United States)

    Chen, Chih Hung; Yang, Jie Chi; Shen, Sarah; Jeng, Ming Chang

    2007-01-01

    In this study, a desktop virtual reality earth motion system (DVREMS) is designed and developed to be applied in the classroom. The system is implemented to assist elementary school students to clarify earth motion concepts using virtual reality principles. A study was conducted to observe the influences of the proposed system in learning.…

  6. Chaco astronomies

    Science.gov (United States)

    Martín López, Alejandro

    2015-08-01

    This presentation discusses the result of 18 years of ethnographic and ethnohistorical studies on Chaco astronomies. The main features of the systems of astronomical knowledge of the Chaco Aboriginal groups will be discussed. In particular we will discuss the relevance of the Milky Way, the role of the visibility of the Pleiades, the ways in which the celestial space is represented, the constitution of astronomical orientations in geographic space, etc. We also address a key feature of their vision of the cosmos: the universe is seen by these groups as a socio-cosmos, where humans and non-humans are related. These are therefore actually socio-cosmologies. We will link this to the theories of Chaco Aboriginal groups about power and political relations.We will discuss how the study of Aboriginal astronomies must be performed along with the studies about astronomies of Creole people and European migrants, as well as anthropological studies about the science teaching in the formal education system and by the mass media. In this form we will discuss the relevance of a very complex system of interethnic relations for the conformation of these astronomical representations and practices.We will also discuss the general methodological implications of this case for the ethnoastronomy studies. In particular we will talk about the advantages of a study of regional scope and about the key importance of put in contact the ethnoastronomy with contemporary issues in social sciences.We also analyze the importance of ethnoastronomy studies in relation to studies of sociology of science, especially astronomy. We also study the potential impact on improving formal and informal science curricula and in shaping effective policies to protect the tangible and intangible astronomical heritage in a context of respect for the rights of Aboriginal groups.

  7. Prototyping scalable digital signal processing systems for radio astronomy using dataflow models

    CERN Document Server

    Sane, Nimish; Harris, Andrew I; Bhattacharyya, Shuvra S

    2012-01-01

    There is a growing trend toward using high-level tools for design and implementation of radio astronomy digital signal processing (DSP) systems. Such tools, for example, those from the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER), are usually platform-specific, and lack high-level, platform-independent, portable, scalable application specifications. This limits the designer's ability to experiment with designs at a high-level of abstraction and early in the development cycle. We address some of these issues using a model-based design approach employing dataflow models. We demonstrate this approach by applying it to the design of a tunable digital downconverter (TDD) used for narrow-bandwidth spectroscopy. Our design is targeted toward an FPGA platform, called the Interconnect Break-out Board (IBOB), that is available from the CASPER. We use the term TDD to refer to a digital downconverter for which the decmation factor and center frequency can be reconfigured without the nee...

  8. The Solar System Ballet: A Kinesthetic Spatial Astronomy Activity

    Science.gov (United States)

    Heyer, Inge; Slater, T. F.; Slater, S. J.; Astronomy, Center; Education ResearchCAPER, Physics

    2011-05-01

    The Solar System Ballet was developed in order for students of all ages to learn about the planets, their motions, their distances, and their individual characteristics. To teach people about the structure of our Solar System can be revealing and rewarding, for students and teachers. Little ones (and some bigger ones, too) often cannot yet grasp theoretical and spatial ideas purely with their minds. Showing a video is better, but being able to learn with their bodies, essentially being what they learn about, will help them understand and remember difficult concepts much more easily. There are three segments to this activity, which can be done together or separately, depending on time limits and age of the students. Part one involves a short introductory discussion about what students know about the planets. Then students will act out the orbital motions of the planets (and also moons for the older ones) while holding a physical model. During the second phase we look at the structure of the Solar System as well as the relative distances of the planets from the Sun, first by sketching it on paper, then by recreating a scaled version in the class room. Again the students act out the parts of the Solar System bodies with their models. The third segment concentrates on recreating historical measurements of Earth-Moon-Sun system. The Solar System Ballet activity is suitable for grades K-12+ as well as general public informal learning activities.

  9. Sensible heat receiver for solar dynamic space power system

    Science.gov (United States)

    Perez-Davis, Marla E.; Gaier, James R.; Petrefski, Chris

    1991-01-01

    A sensible heat receiver is considered which uses a vapor grown carbon fiber-carbon (VGCF/C) composite as the thermal storage medium and which was designed for a 7-kW Brayton engine. This heat receiver stores the required energy to power the system during eclipse in the VGCF/C composite. The heat receiver thermal analysis was conducted through the Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA) software package. The sensible heat receiver compares well with other latent and advanced sensible heat receivers analyzed in other studies, while avoiding the problems associated with latent heat storage salts and liquid metal heat pipes. The concept also satisfies the design requirements for a 7-kW Brayton engine system. The weight and size of the system can be optimized by changes in geometry and technology advances for this new material.

  10. Different Reward Structures to Motivate Student Interaction with Electronic Response Systems in Astronomy

    Science.gov (United States)

    Len, Patrick M.

    Electronic response systems ("clickers") are used in introductory astronomy classes as a real-time assessment tool. Different reward structures for student responses to clicker questions are used to motivate individual participation or group collaboration before responding. The impact of two reward structures on student behavior and learning is investigated. This study finds that a success-bonus incentive (in which individual participation points are doubled when the class attains a threshold success rate) strongly motivated students to collaborate, whereas a participation-only credit (no success-bonus) incentive resulted in one-third of the students answering individually without collaboration. With a participation-only incentive, students who answered individually ("self-testers") were found to have more positive attitudes toward astronomy and science, and higher self-confidence in their learning than students who interacted before answering without a success-bonus incentive ("collaborators"). These collaborators experienced downward shifts in attitudes and self-confidence, in contrast to the static attitudes and self-confidence of self-testers. The implication is that students with little or no background in science prefer to answer collaboratively rather than independently and that these students are also negatively impacted by a one-semester introductory astronomy course.

  11. Study on fault diagnose expert system for large astronomy telescope

    Science.gov (United States)

    Liu, Jia-jing; Luo, Ming-Cheng; Tang, Peng-yi; Wu, Wen-qing; Zhang, Guang-yu; Zhang, Hong-fei; Wang, Jian

    2014-08-01

    The development of astronomical techniques and telescopes currently entered a new vigorous period. The telescopes have trends of the giant, complex, diversity of equipment and wide span of control despite of optical, radio space telescopes. That means, for telescope observatory, the control system must have these specifications: flexibility, scalability, distributive, cross-platform and real-time, especially the fault locating and fault processing is more important when fault or exception arise. Through the analysis of the structure of large telescopes, fault diagnosis expert system of large telescope based on the fault tree and distributed log service is given.

  12. Adiabatic-demagnetization-cooled bolometer system for millimeter continuum astronomy

    International Nuclear Information System (INIS)

    An adiabatic-demagnetization-cooled bolometer system was constructed for the detection of astronomical one-millimeter wavelength continuum radiation. By employing chromium potassium sulfate as a refrigeration agent, bolometers were cooled to temperatures below 0.1 K. The bolometers were composed of a gallium-doped germanium thermistor epoxied to a sapphire substrate coated with a bismuth absorbing film. The most-sensitive detector tested had a measured electrical noise equivalent power (NEP) of 7 x 10-17 watts per root-hertz at a chopping frequency of 20 hertz. This value of the NEP is the lowest yet recorded for a bolometer, and represents a major gain in sensitivity. The theory of both the refrigerator and detector operation is presented and is shown to strongly constrain a useful detector system. In the laboratory, a cryogenic hold time of greater than eight hours has been achieved, with temperatures regulation of 0.1 K to within 14 microK. Such regulation is shown necessary to keep the variations in responsivity of the bolometer within 1%. The measured performance of the refrigerator and bolometer are both found to be in good agreement with theoretical predictions. Spacecraft adaptation of this system is briefly discussed. One-millimeter continuum observations of Cygnus A made with a pumped 3He refrigerator detector system are presented

  13. Armenian Cultural Astronomy

    Science.gov (United States)

    Farmanyan, S. V.; Mickaelian, A. M.

    2015-07-01

    Cultural Astronomy is the reflection of sky events in various fields of nations' culture. In foreign literature this field is also called "Astronomy in Culture" or "Astronomy and Culture". Cultural astronomy is the set of interdisciplinary fields studying the astronomical systems of current or ancient societies and cultures. It is manifested in Religion, Mythology, Folklore, Poetry, Art, Linguistics and other fields. In recent years, considerable attention has been paid to this sphere, particularly international organizations were established, conferences are held and journals are published. Armenia is also rich in cultural astronomy. The present paper focuses on Armenian archaeoastronomy and cultural astronomy, including many creations related to astronomical knowledge; calendars, rock art, mythology, etc. On the other hand, this subject is rather poorly developed in Armenia; there are only individual studies on various related issues (especially many studies related to Anania Shirakatsi) but not coordinated actions to manage this important field of investigation.

  14. CANFAR+Skytree: A Cloud Computing and Data Mining System for Astronomy

    Science.gov (United States)

    Ball, N. M.

    2013-10-01

    To-date, computing systems have allowed either sophisticated analysis of small datasets, as exemplified by most astronomy software, or simple analysis of large datasets, such as database queries. At the Canadian Astronomy Data Centre, we have combined our cloud computing system, the Canadian Advanced Network for Astronomical Research (CANFAR), with the world's most advanced machine learning software, Skytree, to create the world's first cloud computing system for data mining in astronomy. CANFAR provides a generic environment for the storage and processing of large datasets, removing the requirement for an individual or project to set up and maintain a computing system when implementing an extensive undertaking such as a survey pipeline. 500 processor cores and several hundred terabytes of persistent storage are currently available to users, and both the storage and processing infrastructure are expandable. The storage is implemented via the International Virtual Observatory Alliance's VOSpace protocol, and is available as a mounted filesystem accessible both interactively, and to all processing jobs. The user interacts with CANFAR by utilizing virtual machines, which appear to them as equivalent to a desktop. Each machine is replicated as desired to perform large-scale parallel processing. Such an arrangement enables the user to immediately install and run the same astronomy code that they already utilize, in the same way as on a desktop. In addition, unlike many cloud systems, batch job scheduling is handled for the user on multiple virtual machines by the Condor job queueing system. Skytree is installed and run just as any other software on the system, and thus acts as a library of command line data mining functions that can be integrated into one's wider analysis. Thus we have created a generic environment for large-scale analysis by data mining, in the same way that CANFAR itself has done for storage and processing. Because Skytree scales to large data in

  15. Solar Central Receiver Hybrid Power Systems sodium-cooled receiver concept. Final report. Volume III. Appendices

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-01-01

    The overall, long term objective of the Solar Central Receiver Hybrid Power System is to identify, characterize, and ultimately demonstrate the viability and cost effectiveness of solar/fossil, steam Rankine cycle, hybrid power systems that: (1) consist of a combined solar central receiver energy source and a nonsolar energy source at a single, common site, (2) may operate in the base, intermediate, and peaking capacity modes, (3) produce the rated output independent of variations in solar insolation, (4) provide a significant savings (50% or more) in fuel consumpton, and (5) produce power at the minimum possible cost in mills/kWh. It is essential that these hybrid concepts be technically feasible and economically competitive with other systems in the near to mid-term time period (1985-1990) on a commercial scale. The program objective for Phase I is to identify and conceptually characterize solar/fossil steam Rankine cycle, commercial-scale, power plant systems that are economically viable and technically feasible. This volume contains appendices to the conceptual design and systems analysis studies gien in Volume II, Books 1 and 2. (WHK)

  16. Handbook of Practical Astronomy

    CERN Document Server

    Roth, Günter D

    2009-01-01

    With amateurs, students, and teachers of astronomy in high schools and colleges particularly in mind, the Handbook of Practical Astronomy is an essential source to demonstrate trends and variety of astronomical observations. The book presents the substance of celestial bodies for the amateur observer: the planets, the stars, and the galaxies. The sun is the local link to the other stars, the nexus of cosmic evolution. The solar system is made up by the sun and all the celestial bodies orbit it. This system is of special interest for the observing amateur. The Handbook of Practial Astronomy spans astronomy, education and computing. Like many other fields of science, astronomy has become digitized and data rich in recent years. Besides the references at the end of each chapter, there are the notes in the margins with astronomical news and observing highlights on the web.

  17. Design of Receiver Used for Passive Millimeter Wave Imaging System

    Directory of Open Access Journals (Sweden)

    Cheng Zheng

    2013-07-01

    Full Text Available As millimeter wave (MMW electronic technologies have matured, the MMW imaging using for human security inspection is emerging as an effective approach to imaging through obscuring materials, such as clothing for concealed weapons detection or plastic mines. This paper introduces temperature sensitivity firstly and then the fringe-washing functions are derived which decide the structure the antenna array and the receivers of the system BHU-2D. Finally, the fringe-washing functions and their phases are calculated from the frequency responses of 24-receiver, they all show good consistency of the receivers which also can be proved from the test results of receivers. From the final imaging of our system, the 1-2K temperature sensitivity is realized successfully.

  18. Outreach of Astronomy with emphasis to the Solar System by the Space group in Greece

    Science.gov (United States)

    Moussas, X.; Dialynas, K.; Babasides, G.; Fasoulopoulos, G.; Dimitropoulou, V.; Prassopoulos, D.; Kouphos, S.; Spandagos, E.; Strikis, J.

    We have a long tradition in Space and Solar System outreach at the University of Athens (Space Group). We have contributed with many popular science articles in encyclopaedias (a total of some 200000 words), magazines and newspapers, public lectures around Greece and radio and TV programmes. We contribute in exhibitions for the public on many occasions (e.g. The British Exploration of the Planets, an exhibition organized by the British Council, at Eugenides Foundation and The Planetarium, where I prepared some 15 posters). We are preparing an outreach site of Astrophysics with sections for the planets, the exploration of the solar system and solar terrestrial relations. I am preparing several posters for the planets. We organize with the Hellenic Physical Union a series of Astrophysics Lectures at the University of Athens. Together with the Hellenic Physical Union we are planning to produce a theatrical play and CD or DVD concerning the planets. We have excellent collaboration with the amateur astronomers allover Greece and Cyprus. We organize, together with Physics or mathematics teachers in high schools several events related to astronomical observations (e.g. Venus transit, solar eclipe, astronomy nights). 1 We also organize popular science programmes in TV channels. I brief we consider Astronomy and especially the planetary system as a "Great Attractor" of pupil and the general public to science and we use it on every occasion for the benefit of the pupil and science. 2

  19. Early Astronomy

    Science.gov (United States)

    Thurston, Hugh

    The earliest investigations that can be called scientific are concerned with the sky: they are the beginnings of astronomy. Many early civilizations produced astronomical texts, and several cultures that left no written records left monuments and artifacts-ranging from rock paintings to Stonehenge-that show a clear interest in astronomy. Civilizations in China, Mesopotamia, India and Greece had highly developed astronomies, and the astronomy of the Mayas was by no means negligible. Greek astronomy, as developed by the medieval Arab philosophers, evolved into the astronomy of Copernicus. This displaced the earth from the central stationary position that almost all earlier astronomies had assumed. Soon thereafter, in the first decades of the seventeenth century, Kepler found the true shape of the planetary orbits and Galileo introduced the telescope for astronomical observations.

  20. A Fast Adaptive Receive Antenna Selection Method in MIMO System

    Directory of Open Access Journals (Sweden)

    Chaowei Wang

    2013-01-01

    Full Text Available Antenna selection has been regarded as an effective method to acquire the diversity benefits of multiple antennas while potentially reduce hardware costs. This paper focuses on receive antenna selection. According to the proportion between the numbers of total receive antennas and selected antennas and the influence of each antenna on system capacity, we propose a fast adaptive antenna selection algorithm for wireless multiple-input multiple-output (MIMO systems. Mathematical analysis and numerical results show that our algorithm significantly reduces the computational complexity and memory requirement and achieves considerable system capacity gain compared with the optimal selection technique in the same time.

  1. Developing a Global Science and Math Education System Based on Real Astronomy Data

    Science.gov (United States)

    Pennypacker, Carlton

    2015-03-01

    Global Hands-On Universe (GHOU) is an educational system where students use real astronomy data from (largely optical) telescopes to learn fundamental physics, math, astronomy, and technology.GHOU is a good example of a collaborative global education project, where data, software, teacher training methods, curriculum, activities, telescopes, and human resources are developed by many members of GHOU and then shared internationally.Assessments show that in this program students learn more science and math than in conventional classroom teaching, and students change their attitudes towards choosing careers in science and technology.GHOU is an exemplar of appropriate use of computers in the classroom for real data analysis.The International Asteroid Search program of GHOU has helped students discover over 700 asteroids. Half a dozen high schools have named the asteroids they have found after their high school (some from here in Texas!).GHOU has found resonance with many teachers and students around the world, reaching approximately 20,000 global teachers in the International Year of Astronomy in 2009.In addition, activities from French HOU are part of the official French National Curriculum, and exit exam, teacher training syllabus and teacher exit exams. GHOU has found particular enthusiasms in nations with increasing technology basis - for example, GHOU is reaching many teachers in China, Chile, Indonesia, Kenya, Venezuela, with expansion plans for Cuba underway. Some nations, such as Portugal, have reached reasonable fractions of their teachers through GHOU. Workshops are planned in Iran, and HOU colleagues are starting to build a GHOU telescope in Israel. US HOU had trained approximately 1000 teachers in the United States, before the closing of the NSF Teacher Enhancement Section.But as many new large and smaller telescopes come on line - e.g., the Large Synoptic Survey Telescope - the need for GHOU around the world and even the United States will only increase.

  2. Proposed lidar receiver architecture for the CZMIL system

    Science.gov (United States)

    Payment, Andy; Feygels, Viktor; Fuchs, Eran

    2010-04-01

    The Coastal Zone Mapping and Imaging Lidar (CZMIL)1 system is a new generation airborne remote sensing system. The multi-sensor system integrates a lidar system, hyperspectral camera, digital camera, and a positioning system together to seamlessly record data over topographic and bathymetric environments. The recorded data is post-processed using data fusion algorithms to generate image products. In order to amplify the amount of information contained within the data fed to the algorithms, the architecture of the lidar receiver is designed using numerous techniques to maximize the quality of the recorded data. The receiver architecture employs commercial photomultiplier tubes operated in a logarithmic mode coupled to 10bit, 1GHz analog to digital converters. This architecture achieves sufficient dynamic range to support operating the system in both terrestrial and ocean environments. The multi-channel design of the lidar system requires the digitization of 9 channels of optical return signal data. The resulting large data volume necessitated design of a novel data reduction strategy. These important aspects of the lidar receiver's design are presented. The strategies illustrate how the receiver's architecture is designed to optimize the fidelity of the recorded data.

  3. SDR implementation of the receiver of adaptive communication system

    Science.gov (United States)

    Skarzynski, Jacek; Darmetko, Marcin; Kozlowski, Sebastian; Kurek, Krzysztof

    2016-04-01

    The paper presents software implementation of a receiver forming a part of an adaptive communication system. The system is intended for communication with a satellite placed in a low Earth orbit (LEO). The ability of adaptation is believed to increase the total amount of data transmitted from the satellite to the ground station. Depending on the signal-to-noise ratio (SNR) of the received signal, adaptive transmission is realized using different transmission modes, i.e., different modulation schemes (BPSK, QPSK, 8-PSK, and 16-APSK) and different convolutional code rates (1/2, 2/3, 3/4, 5/6, and 7/8). The receiver consists of a software-defined radio (SDR) module (National Instruments USRP-2920) and a multithread reception software running on Windows operating system. In order to increase the speed of signal processing, the software takes advantage of single instruction multiple data instructions supported by x86 processor architecture.

  4. Theory of cellwise optimization for solar central receiver system

    Science.gov (United States)

    Lipps, F. W.

    1985-05-01

    Cost effective optimization of the solar central receiver system is primarily concerned with the distribution of heliostats in the collector field, including the boundaries of the field. The cellwise optimization procedure determines the optimum cell usage and heliostat spacing parameters for each cell in the collector field. Spacing parameters determine the heliostat density and neighborhood structure uniformly in each cell. Consequently, the cellwise approach ignores heliostat mismatch at cell boundaries. Ignoring the cell boundary problem permits an easy solution for the optimum in terms of appropriately defined annual average data. Insolation, receiver interception, shading and blocking, cosine effects, and the cost parameters combine to control the optimum. Many trade offs are represented. Outputs include the receiver flux density distribution for design time, coefficients for an actual layout, the optimum boundary and various performance and cost estimates for the optimum field. It is also possible to optimize receiver size and tower height by a repeated application of the field optimization procedure.

  5. High temperature helical tubular receiver for concentrating solar power system

    Science.gov (United States)

    Hossain, Nazmul

    In the field of conventional cleaner power generation technology, concentrating solar power systems have introduced remarkable opportunity. In a solar power tower, solar energy concentrated by the heliostats at a single point produces very high temperature. Falling solid particles or heat transfer fluid passing through that high temperature region absorbs heat to generate electricity. Increasing the residence time will result in more heat gain and increase efficiency. A novel design of solar receiver for both fluid and solid particle is approached in this paper which can increase residence time resulting in higher temperature gain in one cycle compared to conventional receivers. The helical tubular solar receiver placed at the focused sunlight region meets the higher outlet temperature and efficiency. A vertical tubular receiver is modeled and analyzed for single phase flow with molten salt as heat transfer fluid and alloy625 as heat transfer material. The result is compared to a journal paper of similar numerical and experimental setup for validating our modeling. New types of helical tubular solar receivers are modeled and analyzed with heat transfer fluid turbulent flow in single phase, and granular particle and air plug flow in multiphase to observe the temperature rise in one cyclic operation. The Discrete Ordinate radiation model is used for numerical analysis with simulation software Ansys Fluent 15.0. The Eulerian granular multiphase model is used for multiphase flow. Applying the same modeling parameters and boundary conditions, the results of vertical and helical receivers are compared. With a helical receiver, higher temperature gain of heat transfer fluid is achieved in one cycle for both single phase and multiphase flow compared to the vertical receiver. Performance is also observed by varying dimension of helical receiver.

  6. New cryogenic system of the next-generation infrared astronomy mission SPICA

    Science.gov (United States)

    Ogawa, H.; Nakagawa, T.; Matsuhara, H.; Shinozaki, K.; Goto, K.; Isobe, N.; Kawada, M.; Mizutani, T.; Sato, Y.; Sugita, H.; Takeuchi, S.; Yamawaki, T.; Shibai, H.

    2016-07-01

    We present the new design of the cryogenic system of the next-generation infrared astronomy mission SPICA under the new framework. The new design employs the V-groove design for radiators, making the best use of the Planck heritage. The new design is based on the ESA-JAXA CDF study (NG-CryoIRTel, CDF-152(A)) with a 2 m telescope, and we modified the CDF design to accommodate the 2.5 m telescope to meet the science requirements of SPICA. The basic design concept of the SPICA cryogenic system is to cool the Science Instrument Assembly (SIA, which is the combination of the telescope and focal-plane instruments) below 8K by the combination of the radiative cooling system and mechanical cryocoolers without any cryogen.

  7. A wide-band, active antenna system for long wavelength radio astronomy

    CERN Document Server

    Hicks, Brian C; Stewart, Kenneth P; Erickson, William C; Ray, Paul S; Kassim, Namir E; Burns, Steve; Clarke, Tracy; Schmitt, Henrique; Craig, Joe; Hartman, Jake; Weiler, Kurt W

    2012-01-01

    We describe an "active" antenna system for HF/VHF (long wavelength) radio astronomy that has been successfully deployed 256-fold as the first station (LWA1) of the planned Long Wavelength Array. The antenna system, consisting of crossed dipoles, an active balun/preamp, a support structure, and a ground screen has been shown to successfully operate over at least the band from 20 MHz (15 m wavelength) to 80 MHz (3.75 m wavelength) with a noise figure that is at least 6 dB better than the Galactic background emission noise temperature over that band. Thus, the goal to design and construct a compact, inexpensive, rugged, and easily assembled antenna system that can be deployed many-fold to form numerous large individual "stations" for the purpose of building a large, long wavelength synthesis array telescope for radio astronomical and ionospheric observations was met.

  8. Comparative Performance Assessment For Central Receiver CPV Systems

    Science.gov (United States)

    Lasich, John B.; Thomas, Ian; Verlinden, Pierre J.; Lewandowski, Allan; Heartag, Wolfgang; Wright, Mark

    2011-12-01

    A Central receiver Concentrating PV (C2PV) system has the potential to be the optimum solar energy generation system for utility scale because it combines the high efficiency of CPV with the low cost of a heliostat collector. Due to the off axis nature of a heliostat central receiver concentrator a cosine efficiency loss is incurred and, unlike `normal' tracking CPV lens and dish systems, the optical performance varies with time and site latitude. To investigate the optical performance of a C2PV system a ray trace model has been developed and the performance of a representative C2PV system is modelled throughout the year and at different site latitudes. The cosine loss and latitude dependence are put into perspective by calculating the annual average optical efficiency and testing its sensitivity to variations in site latitude. These values are then used to estimate a system performance by applying efficiencies for solar cell, balance of system and operational factors. This system efficiency is finally compared to published data for `normal' tracking CPV dish and lens systems. Modelled annual average AC system efficiency for the C2PV system was calculated to be 21% at 40° latitude and 19% at 15° latitude. These annual average AC system efficiencies are shown to be similar to those reported for typical dish and lens CPV systems when they are adjusted to use a total collector area baseline.

  9. Systemic Reform of Astronomy Curriculum in the Montgomery County Public Schools

    Science.gov (United States)

    Szesze, M.; Kahl, S.; Janney, D.

    2002-09-01

    In the Montgomery County Public Schools (MCPS), the science curriculum is undergoing a comprehensive systemic review in an effort to revise the system's curriculum and the entire instructional program. As a part of this overall effort, MCPS has developed a framework for the astronomy curriculum that includes a rationale, essential indicators, and blueprints. The school system is partnering with the NASA Goddard Space Flight Center to involve professional astronomers/space scientists as content advisors to ensure science content accuracy and currency. Through this partnership, many NASA developed educational materials have been made available to the school system to assist with the instructional sequences. This new policy has resulted in the development of a clear and coherent astronomy curriculum for grades K-8. The blueprint is written in the form of a set of indicators which identify the exact skills and knowledge that need to be taught at each grade level so that students will meet and exceed state, national, and international standards. Each blueprint also includes the enduring understandings and essential questions that students should focus on for that specific unit of study, a proposed instructional sequence, and assessment and differentiation ideas. Using these blueprints, teachers will create curriculum guides that include model lessons, model assignments, concept maps, resources, assessment samples, and strategies for differentiating the curriculum to meet the needs of a wide range of learners. In addition, a 45 hour certification training course is being developed to train in service teachers in a wide range of space science disciplines from seasons to cosmology. The course is being developed and will be taught by a team composed of space scientists and master educational trainers. Pilot testing of the curriculum and the training course will begin in Fall 2002.

  10. A heat receiver design for solar dynamic space power systems

    Science.gov (United States)

    Baker, Karl W.; Dustin, Miles O.; Crane, Roger

    1990-01-01

    An advanced heat pipe receiver designed for a solar dynamic space power system is described. The power system consists of a solar concentrator, solar heat receiver, Stirling heat engine, linear alternator and waste heat radiator. The solar concentrator focuses the sun's energy into a heat receiver. The engine and alternator convert a portion of this energy to electric power and the remaining heat is rejected by a waste heat radiator. Primary liquid metal heat pipes transport heat energy to the Stirling engine. Thermal energy storage allows this power system to operate during the shade portion of an orbit. Lithium fluoride/calcium fluoride eutectic is the thermal energy storage material. Thermal energy storage canisters are attached to the midsection of each heat pipe. The primary heat pipes pass through a secondary vapor cavity heat pipe near the engine and receiver interface. The secondary vapor cavity heat pipe serves three important functions. First, it smooths out hot spots in the solar cavity and provides even distribution of heat to the engine. Second, the event of a heat pipe failure, the secondary heat pipe cavity can efficiently transfer heat from other operating primary heat pipes to the engine heat exchanger of the defunct heat pipe. Third, the secondary heat pipe vapor cavity reduces temperature drops caused by heat flow into the engine. This unique design provides a high level of reliability and performance.

  11. System and Circuit Design Aspects for CMOS Wireless Handset Receivers

    DEFF Research Database (Denmark)

    Mikkelsen, Jan H.

    developments in CMOS technology are considered and the short-comings from an analog design perspective are evaluated. The lack of high quality passive devices, inductors in particular, is found to be one of the major obstacles in achieving a fully integrated RF design based on CMOS. Following this, an overview......The presented work deals with system and circuit design aspects for Complementary Metal Oxide Semiconductor (CMOS) implementations of wireless handset receivers. First, an overview, from a historic perspective, on the use of CMOS in cellular applications is provided. Based on this the tremendous...... Division Duplex) direct-conversion receiver (DCR). The wideband nature of the UMTS signal opens up for simple DC-offset cancellation schemes. In line of this the use of highpass filtering as a means to reduce the DC-offset is pursued using link simulations. To simplify receiver planning it is common...

  12. Note: Optical receiver system for 152-channel magnetoencephalography

    Science.gov (United States)

    Kim, Jin-Mok; Kwon, Hyukchan; Yu, Kwon-kyu; Lee, Yong-Ho; Kim, Kiwoong

    2014-11-01

    An optical receiver system composing 13 serial data restore/synchronizer modules and a single module combiner converted optical 32-bit serial data into 32-bit synchronous parallel data for a computer to acquire 152-channel magnetoencephalography (MEG) signals. A serial data restore/synchronizer module identified 32-bit channel-voltage bits from 48-bit streaming serial data, and then consecutively reproduced 13 times of 32-bit serial data, acting in a synchronous clock. After selecting a single among 13 reproduced data in each module, a module combiner converted it into 32-bit parallel data, which were carried to 32-port digital input board in a computer. When the receiver system together with optical transmitters were applied to 152-channel superconducting quantum interference device sensors, this MEG system maintained a field noise level of 3 fT/√Hz @ 100 Hz at a sample rate of 1 kSample/s per channel.

  13. Note: Optical receiver system for 152-channel magnetoencephalography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin-Mok; Kwon, Hyukchan; Yu, Kwon-kyu; Lee, Yong-Ho; Kim, Kiwoong [Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

    2014-11-15

    An optical receiver system composing 13 serial data restore/synchronizer modules and a single module combiner converted optical 32-bit serial data into 32-bit synchronous parallel data for a computer to acquire 152-channel magnetoencephalography (MEG) signals. A serial data restore/synchronizer module identified 32-bit channel-voltage bits from 48-bit streaming serial data, and then consecutively reproduced 13 times of 32-bit serial data, acting in a synchronous clock. After selecting a single among 13 reproduced data in each module, a module combiner converted it into 32-bit parallel data, which were carried to 32-port digital input board in a computer. When the receiver system together with optical transmitters were applied to 152-channel superconducting quantum interference device sensors, this MEG system maintained a field noise level of 3 fT/√Hz @ 100 Hz at a sample rate of 1 kSample/s per channel.

  14. Mathematical Astronomy in India

    Science.gov (United States)

    Plofker, Kim

    Astronomy in South Asia's Sanskrit tradition, apparently originating in simple calendric computations regulating the timing of ancient ritual practices, expanded over the course of two or three millennia to include detailed spherical models, an endless variety of astrological systems, and academic mathematics in general. Assimilating various technical models, methods, and genres from the astronomy of neighboring cultures, Indian astronomers created new forms that were in turn borrowed by their foreign counterparts. Always recognizably related to the main themes of Eurasian geocentric mathematical astronomy, Indian astral science nonetheless maintained its culturally distinct character until Keplerian heliocentrism and Newtonian mechanics replaced it in colonial South Asia's academic mainstream.

  15. Astronomy in Ukraine

    CERN Document Server

    Pavlenko, Ya V; Vavilova, I B; Pavlenko, Ya.V.

    2005-01-01

    The current and prospective status of astronomical research in Ukraine is discussed. A brief history of astronomical research in Ukraine is presented and the system organizing scientific activity is described, including astronomy education, institutions and staff, awarding higher degrees/titles, government involvement, budgetary investments and international cooperation. Individuals contributing significantly to the field of astronomy and their accomplishments are mentioned. Major astronomical facilities, their capabilities, and their instrumentation are described. In terms of the number of institutions and personnel engaged in astronomy, and of past accomplishments, Ukraine ranks among major nations of Europe. Current difficulties associated with political, economic and technological changes are addressed and goals for future research activities presented.

  16. The road to OLFAR - a roadmap to interferometric long-wavelength radio astronomy using miniaturized distributed space systems

    NARCIS (Netherlands)

    Engelen, Steven; Quillien, Kevin A.; Verhoeven, Chris; Noroozi, Arash; Sundaramoorthy, Prem; Veen, van der Alle-Jan; Rajan, Raj Thilak; Boonstra, Albert-Jan; Bentum, Mark; Meijerink, Arjan; Budianu, Alex

    2013-01-01

    The Orbiting Low Frequency Antennas for Radio Astronomy (OLFAR) project aims to develop a space-based low frequency radio telescope that will explore the universe's so-called dark ages, map the interstellar medium, and discover planetary and solar bursts in other solar systems. The telescope, compos

  17. A 200kW central receiver CPV system

    Energy Technology Data Exchange (ETDEWEB)

    Lasich, John, E-mail: jbl@raygen.com; Thomas, Ian, E-mail: ithomas@raygen.com; Hertaeg, Wolfgang; Shirley, David; Faragher, Neil; Erenstrom, Neil; Carter, Sam; Cox, Brian; Zuo, Xinyi [Raygen Resources Pty. Ltd., 15 King Street, Blackburn, Victoria, 3130 (Australia)

    2015-09-28

    Raygen Resources has recently completed a Central Receiver CPV (CSPV) pilot plant in Central Victoria, Australia. The system is under final commissioning and initial operation is expected in late April 2015. The pilot demonstrates a full scale CSPV repeatable unit in a form that is representative of a commercial product and provides a test bed to prove out performance and reliability of the CSPV technology. Extensive testing of the system key components: dense array module, wireless solar powered heliostat and control system has been performed in the laboratory and on sun. Results from this key component testing are presented herein.

  18. A 200kW central receiver CPV system

    Science.gov (United States)

    Lasich, John; Thomas, Ian; Hertaeg, Wolfgang; Shirley, David; Faragher, Neil; Erenstrom, Neil; Carter, Sam; Cox, Brian; Zuo, Xinyi

    2015-09-01

    Raygen Resources has recently completed a Central Receiver CPV (CSPV) pilot plant in Central Victoria, Australia. The system is under final commissioning and initial operation is expected in late April 2015. The pilot demonstrates a full scale CSPV repeatable unit in a form that is representative of a commercial product and provides a test bed to prove out performance and reliability of the CSPV technology. Extensive testing of the system key components: dense array module, wireless solar powered heliostat and control system has been performed in the laboratory and on sun. Results from this key component testing are presented herein.

  19. Optimizing Profits from a System of Accounts Receivable

    OpenAIRE

    Robert E. Stanford

    1989-01-01

    We develop a model of the period-by-period maintenance cost and interest income accumulation resulting from charges to a system of accounts receivable, and establish conditions under which the present value of the expected profit generated by the charges reaches its greatest attainable levels. The profit measure is expressed as a function of the rate at which active accounts are paid off, which is initially treated as an independent variable, then as a function of the rate of interest charged...

  20. MIMO OFDM receivers for systems with IQ imbalances

    OpenAIRE

    Tarighat, Alireza; Sayed, A.H.

    2005-01-01

    Orthogonal frequency division multiplexing (OFDM) is a widely recognized modulation scheme for high data rate communications. However, the implementation of OFDM-based systems suffers from in-phase and quadrature-phase (IQ) imbalances in the front-end analog processing. Such imbalances are caused by the analog processing of the received radio frequency (RF) signal, and they cannot be efficiently or entirely eliminated in the analog domain. The resulting IQ distortion limits the achievable ope...

  1. Novel calibration system with sparse wires for CMB polarization receivers

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, O.; /KEK, Tsukuba /Chicago U., KICP; Nguyen, H.; /Fermilab; Bischoff, C.; /Chicago U., KICP /Harvard-Smithsonian Ctr. Astrophys.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

    2011-07-01

    B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

  2. Conceptual design of advanced central receiver power system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tracey, T. R.

    1978-09-01

    The design of a 300 MWe tower focus power plant which uses molten salt heat transfer fluids and sensible heat storage is described in detail. The system consists of nine heliostat fields with 7711 heliostats in each. Four cavity receivers are located at the top of a 155-meter tower. Tasks include: (1) review and analysis of preliminary specification; (2) parametric analysis; (3) selection of preferred configuration; (4) commercial plant conceptual design; (5) assessment of commercial-sized advanced central power system; (6) development plan; (7) program plan; (8) reports and data; (9) program management; (10) safety analysis; and (11) material study and test program. (WHK)

  3. Simplified MMSE Detectors for Turbo Receiver in BICM MIMO Systems

    Institute of Scientific and Technical Information of China (English)

    Juan Han; Chao Tang; Qiu-Ju Wang; Zi-Yuan Zhu; Shan Tang

    2013-01-01

    In this article,two methods adopting simplified minimum mean square error (MMSE) filter with soft parallel interference cancellation (SPIC) axe discussed for turbo receivers in bit interleaved coded modulation (BICM) multiple-input multiple-output (MIMO) systems.The proposed methods are utilized in the non-first iterative process of turbo receiver to suppress residual interference and noise.By modeling the components of residual interference after SPIC plus the noise as uncorrelated Gaussian random variables,the matrix inverse for weighting vector of conventional MMSE becomes unnecessary.Thus the complexity can be greatly reduced with only slight performance deterioration.By introducing optimal ordering to SPIC,performance gap between simplified MMSE and conventional MMSE further narrows.Monte Carlo simulation results confirm that the proposed algorithms can achieve almost the same performance as the conventional MMSE SPIC in various MIMO configurations,but with much lower computational complexity.

  4. Sustainable Astronomy

    Science.gov (United States)

    Blaha, C.; Goetz, J.; Johnson, T.

    2011-09-01

    Through our International Year of Astronomy outreach effort, we established a sustainable astronomy program and curriculum in the Northfield, Minnesota community. Carleton College offers monthly open houses at Goodsell Observatory and donated its recently "retire" observing equipment to local schools. While public evenings continue to be popular, the donated equipment was underutilized due to a lack of trained student observing assistants. With sponsorship from NASA's IYA Student Ambassador program, the sustainable astronomy project began in 2009 to generate greater interest in astronomy and train middle school and high school students as observing assistants. Carleton physics majors developed curricular materials and instituted regular outreach programs for grades 6-12. The Northfield High School Astronomy Club was created, and Carleton undergraduates taught high school students how to use telescopes and do CCD imaging. During the summer of 2009, Carleton students began the Young Astronomers Summer Experience (YASE) program for middle school students and offered a two-week, astronomy-rich observing and imaging experience at Goodsell Observatory. In concert with NASA's Summer of Innovation initiative, the YASE program was offered again in 2010 and engaged a new group of local middle school students in hands-on scientific experiments and observing opportunities. Members of the high school astronomy club now volunteer as observing assistants in the community and graduates of the YASE programs are eager to continue observing as members of a public service astronomy club when they enter the Northfield High School. These projects are training future scientists and will sustain the public's interest in astronomy long after the end of IYA 2009.

  5. Radio astronomy

    Science.gov (United States)

    Kellermann, Kenneth I.; Heeschen, David; Backer, Donald C.; Cohen, Marshall H.; Davis, Michael; Depater, Imke; Deyoung, David; Dulk, George A.; Fisher, J. R.; Goss, W. Miller

    1991-01-01

    The following subject areas are covered: (1) scientific opportunities (millimeter and sub-millimeter wavelength astronomy; meter to hectometer astronomy; the Sun, stars, pulsars, interstellar masers, and extrasolar planets; the planets, asteroids, and comets; radio galaxies, quasars, and cosmology; and challenges for radio astronomy in the 1990's); (2) recommendations for new facilities (the millimeter arrays, medium scale instruments, and small-scale projects); (3) continuing activities and maintenance, upgrading of telescopes and instrumentation; (4) long range programs and technology development; and (5) social, political, and organizational considerations.

  6. Greek astronomy

    CERN Document Server

    Heath, Sir Thomas L

    2011-01-01

    Astronomy as a science began with the Ionian philosophers, with whom Greek philosophy and mathematics also began. While the Egyptians and Babylonians had accomplished much of astronomical worth, it remained for the unrivalled speculative genius of the Greeks, in particular, their mathematical genius, to lay the foundations of the true science of astronomy. In this classic study, a noted scholar discusses in lucid detail the specific advances made by the Greeks, many of whose ideas anticipated the discoveries of modern astronomy.Pythagoras, born at Samos about 572 B.C., was probably the first

  7. ALO4: Angle Localization and Orientation System with Four Receivers

    Directory of Open Access Journals (Sweden)

    Santiago Elvira

    2014-09-01

    Full Text Available This paper presents a 2D indoor localization and orientation system based on a TDOA (Time Difference of Arrival technique. It uses an array of receivers (four low- cost ultrasonic resonant devices in a square distribution to implement low-computational-effort DOA (Direction of Arrival algorithms, based on assumed plane-wave reception. The system only demands two transmitters at well-known positions on the ceiling of the room for obtaining the node position and orientation when it is deployed on the floor of the room. This system has been tested using a Xilinx Spartan-3A FPGA that implements a 52 MHz MicroBlaze. The experimental results include a total of 1,440 points, obtaining a mean localization error of 5.17 cm and a mean orientation error of 3.34o. For this system, the localization and orientation processes are executed in less than 50 us.

  8. THE ANALYSIS OF SEWAGE SYSTEM INFLUENCE ON RECEIVERS

    Directory of Open Access Journals (Sweden)

    Kamil Pluta

    2015-11-01

    Full Text Available Reducing waste water discharges to the receiver is now one of the most important activities to ensure the protection of surface waters. This is caused mainly by progressive urbanization and increasing impervious surfaces. Discharge of sewage with a large load of pollutants affect the receivers in a negative way. The quality of waste water varies and depends on many factors, but above all, it is closely linked with sewer system applied to the drainage catchment. The article presents a comparative analysis of the environmental impact of three basic sewer systems: combined, separate and semi-separate. The analysis was performed for a typical urban catchment, using the average concentration of the basic indicators of pollution, which total suspended solids, nitrogen and phosphorus, COD, BOD5, selected heavy metals are merked. The results concluded that each of these sewer systems characterized by varying environmental impacts depending on the indicator of pollution. The best of today available technical solutions seem to be semi-separate sewer system, using the storage tank with the control in real time (RTC for controlling the flow.

  9. FAST CONVERGENT MONTE CARLO RECEIVER FOR OFDM SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Wu Lili; Liao Guisheng; Bao Zheng; Shang Yong

    2005-01-01

    The paper investigates the problem of the design of an optimal Orthogonal Frequency Division Multiplexing (OFDM) receiver against unknown frequency selective fading. A fast convergent Monte Carlo receiver is proposed. In the proposed method, the Markov Chain Monte Carlo (MCMC) methods are employed for the blind Bayesian detection without channel estimation. Meanwhile, with the exploitation of the characteristics of OFDM systems, two methods are employed to improve the convergence rate and enhance the efficiency of MCMC algorithms.One is the integration of the posterior distribution function with respect to the associated channel parameters, which is involved in the derivation of the objective distribution function; the other is the intra-symbol differential coding for the elimination of the bimodality problem resulting from the presence of unknown fading channels. Moreover, no matrix inversion is needed with the use of the orthogonality property of OFDM modulation and hence the computational load is significantly reduced. Computer simulation results show the effectiveness of the fast convergent Monte Carlo receiver.

  10. Combustion system for hybrid solar fossil fuel receiver

    Science.gov (United States)

    Mehos, Mark S.; Anselmo, Kenneth M.; Moreno, James B.; Andraka, Charles E.; Rawlinson, K. Scott; Corey, John; Bohn, Mark S.

    2004-05-25

    A combustion system for a hybrid solar receiver comprises a pre-mixer which combines air and fuel to form an air-fuel mixture. The mixture is introduced tangentially into a cooling jacket. A burner plenum is fluidically connected to the cooling jacket such that the burner plenum and the cooling jacket are arranged in thermal contact with one another. The air-fuel mixture flows through the cooling jacket cooling the burner plenum to reduce pre-ignition of the air-fuel mixture in the burner plenum. A combustion chamber is operatively associated with and open to the burner plenum to receive the air-fuel mixture from the burner plenum. An igniter is operatively positioned in the combustion chamber to combust the air-fuel mixture, releasing heat. A recuperator is operatively associated with the burner plenum and the combustion chamber and pre-heats the air-fuel mixture in the burner plenum with heat from the combustion chamber. A heat-exchanger is operatively associated and in thermal contact with the combustion chamber. The heat-exchanger provides heat for the hybrid solar receiver.

  11. 40 CFR 142.303 - Which size public water systems can receive a small system variance?

    Science.gov (United States)

    2010-07-01

    ... receive a small system variance? 142.303 Section 142.303 Protection of Environment ENVIRONMENTAL... IMPLEMENTATION Variances for Small System General Provisions § 142.303 Which size public water systems can receive a small system variance? (a) A State exercising primary enforcement responsibility for...

  12. Fundamental Astronomy and Solar System Dynamics : Invited Papers Honoring Prof. Walter Fricke on the occasion of his 70th birthday

    CERN Document Server

    Lieske, J; Seidelmann, P

    1986-01-01

    "Fundamental Astronomy and Solar System Dynamics", a program of invited papers honoring Professor Walter Fricke, who for thirty years has been Director of the Astronomisches Rechen lnstitut in Heidelberg, was held at the Thompson Conference Center of the University of Texas at Austin on Wednesday 27 March 1985 on the occasion of his seventieth birthday and retirement as Director of ARl. Professor Fricke's contributions to astronomy encompass the areas of galactic dynamics, radial velocities, stellar statistics. the fundamental reference system and the constant of precession. Participants were welcomed to the Uni versi ty of Texas by Professor J. Parker Lamb, Chairman of the Department of Aerospace Engineering and Engineering Mechanics. The presentations ranged from discussions of astrometric problems concerned with the reference system, the constant of precession, major and minor planet observations, planetary ephemerides and lunar and satellite laser ranging, to a study of disc galaxies in massive halos. The...

  13. Conceptual frameworks in astronomy

    Science.gov (United States)

    Pundak, David

    2016-06-01

    How to evaluate students' astronomy understanding is still an open question. Even though some methods and tools to help students have already been developed, the sources of students' difficulties and misunderstanding in astronomy is still unclear. This paper presents an investigation of the development of conceptual systems in astronomy by 50 engineering students, as a result of learning a general course on astronomy. A special tool called Conceptual Frameworks in Astronomy (CFA) that was initially used in 1989, was adapted to gather data for the present research. In its new version, the tool included 23 questions, and five to six optional answers were given for each question. Each of the answers was characterized by one of the four conceptual astronomical frameworks: pre-scientific, geocentric, heliocentric and sidereal or scientific. The paper describes the development of the tool and discusses its validity and reliability. Using the CFA we were able to identify the conceptual frameworks of the students at the beginning of the course and at its end. CFA enabled us to evaluate the paradigmatic change of students following the course and also the extent of the general improvement in astronomical knowledge. It was found that the measure of the students’ improvement (gain index) was g = 0.37. Approximately 45% of the students in the course improved their understanding of conceptual frameworks in astronomy and 26% deepened their understanding of the heliocentric or sidereal conceptual frameworks.

  14. Effect of High Receiver Thermal Loss Per Unit Area on the Performance of Solar Central Receiver Systems Having Optimum Heliostat Fields and Optimum Receiver Aperture Areas.

    Science.gov (United States)

    Pitman, Charles L.

    Recent efforts in solar central receiver research have been directed toward high temperature applications. Associated with high temperature processes are greater receiver thermal losses due to reradiation and convection. This dissertation examines the performance of central receiver systems having optimum heliostate fields and receiver aperture areas as a function of receiver thermal loss per unit area of receiver aperture. The results address the problem of application optimization (loss varies) as opposed to the problem of optimization of a design for a specific application (loss fixed). A reasonable range of values for the primary independent variable L (the average reradiative and convective loss per unit area of receiver aperture) and a reasonable set of design assumptions were first established. The optimum receiver aperture area, number and spacings of heliostats, and field boundary were then determined for two tower focal heights and for each value of L. From this, the solar subsystem performance for each optimized system was calculated. Heliostat field analysis and optimization required a detailed computational analysis. A significant modification to the standard method of solving the optimization equations, effectively a decoupling of the solution process into collector and receiver subsystem parts, greatly aided the analysis. Results are presented for tower focal heights of 150 and 180 m. Values of L ranging from 0.04 to 0.50 MW m('-2) were considered, roughly corresponding to working fluid temperatures (at receiver exit) in the range of 650 to 1650 C. As L increases over this range, the receiver thermal efficiency and the receiver interception factor decrease. The optimal power level drops by almost half, and the cost per unit of energy produced increases by about 25% for the base case set of design assumptions. The resulting decrease in solar subsystem efficiency (relative to the defined annual input energy) from 0.57 to 0.35 is about 40% and is a

  15. Controller-area-network bus control and monitor system for a radio astronomy interferometer.

    Science.gov (United States)

    Woody, David P; Wiitala, Bradley; Scott, Stephen L; Lamb, James W; Lawrence, Ronald P; Giovanine, Curt; Fredsti, Sancar J; Beard, Andrew; Pryke, Clem; Loh, Michael; Greer, Christopher H; Cartwright, John K; Gutierrez-Kraybill, Colby; Bolatto, Alberto D; Muchovej, Stephen J C

    2007-09-01

    We describe the design and implementation of a controller-area-network bus (CANbus) monitor and control system for a millimeter wave interferometer. The Combined Array for Research in Millimeter-wave Astronomy (CARMA) is a 15-antenna connected-element interferometer for astronomical imaging, created by the merger of two university observatories. Its new control system relies on a central computer supervising a variety of subsystem computers, many of which control distributed intelligent nodes over CANbus. Subsystems are located in the control building and in individual antennas and communicate with the central computer via Ethernet. Each of the CAN modules has a very specific function, such as reading an antenna encoder or tuning an oscillator. Hardware for the modules was based on a core design including a commercial CANbus-enabled single-board computer and some standard circuitry for interfacing to peripherals. Hardware elements were added or changed as necessary for the specific module types. Similarly, a base set of embedded code was implemented for essential common functions such as CAN message handling and time keeping and extended to implement the required functionality for the different hardware. Using a standard CAN messaging protocol designed to fit the requirements of CARMA and a well-defined interface to the high-level software allowed separate development of high-level code and embedded code with minimal integration problems. Over 30 module types have been implemented and successfully deployed in CARMA, which is now delivering excellent new science data. PMID:17902962

  16. Boeing Satellite Television Airplane Receiving System (STARS) performance

    Science.gov (United States)

    Vertatschitsch, Edward J.; Fitzsimmons, George W.

    1995-01-01

    Boeing Defense and Space Group is developing a Satellite Television Airplane Receiving System (STARS) capable of delivering Direct Broadcast Satellite (DBS) television to an aircraft in-flight. This enables a new service for commercial airplanes that will make use of existing and future DBS systems. The home entertainment satellites, along with STARS, provide a new mobile satellite communication application. This paper will provide a brief background of the antenna issues associated with STARS for commercial airplanes and then describe the innovative Boeing phased-array solution to these problems. The paper then provides a link budget of the STARS using the Hughes DBS as an example, but the system will work with all of the proposed DBS satellites in the 12.2-12.7 GHz band. It concludes with operational performance calculations of the STARS system, supported by measured test data of an operational 16-element subarray. Although this system is being developed for commercial airplanes, it is well suited for a wide variety of mobile military and other commercial communications systems in air, on land and at sea. The applications include sending high quality video for the digital battlefield and large volumes of data on the information superhighway at rates in excess of 350 Mbps.

  17. Development of an Experimental Phased Array Feed System and Algorithms for Radio Astronomy

    Science.gov (United States)

    Landon, Jonathan C.

    Phased array feeds (PAFs) are a promising new technology for astronomical radio telescopes. While PAFs have been used in other fields, the demanding sensitivity and calibration requirements in astronomy present unique new challenges. This dissertation presents some of the first astronomical PAF results demonstrating the lowest noise temperature and highest sensitivity at the time (66 Kelvin and 3.3 m^2/K, respectively), obtained using a narrowband (425 kHz bandwidth)prototype array of 19 linear co-polarized L-band dipoles mounted at the focus of the Green Bank 20 Meter Telescope at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia. Results include spectral line detection of hydroxyl (OH) sources W49N and W3OH, and some of the first radio camera images made using a PAF, including an image of the Cygnus X region. A novel array Y-factor technique for measuring the isotropic noise response of the array is shown along with experimental measurements for this PAF. Statistically optimal beamformers (Maximum SNR and MVDR) are used throughout the work. Radio-frequency interference (RFI) mitigation is demonstrated experimentally using spatial cancelation with the PAF. Improved RFI mitigation is achieved in the challenging cases of low interference-to-noise ratio (INR) and moving interference by combining subspace projection (SP) beamforming with a polynomial model to track a rank 1 subspace. Limiting factors in SP are investigated including sample estimation error, subspace smearing, noise bias, and spectral scooping; each of these factors is overcome with the polynomial model and prewhitening. Numerical optimization leads to the polynomial subspace projection (PSP) method, and least-squares fitting to the series of dominant eigenvectors over a series of short term integrations (STIs) leads to the eigenvector polynomial subspace projection (EPSP) method. Expressions for the gradient, Hessian, and Jacobian are given for use in numerical optimization

  18. Conceptual design of advanced central receiver power systems sodium-cooled receiver concept. Volume 2, Book 2. Appendices. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    The appendices include: (A) design data sheets and P and I drawing for 100-MWe commercial plant design, for all-sodium storage concept; (B) design data sheets and P and I drawing for 100-MWe commercial plant design, for air-rock bed storage concept; (C) electric power generating water-steam system P and I drawing and equipment list, 100-MWe commercial plant design; (D) design data sheets and P and I drawing for 281-MWe commercial plant design; (E) steam generator system conceptual design; (F) heat losses from solar receiver surface; (G) heat transfer and pressure drop for rock bed thermal storage; (H) a comparison of alternative ways of recovering the hydraulic head from the advanced solar receiver tower; (I) central receiver tower study; (J) a comparison of mechanical and electromagnetic sodium pumps; (K) pipe routing study of sodium downcomer; and (L) sodium-cooled advanced central receiver system simulation model. (WHK)

  19. Neutrino astronomy

    International Nuclear Information System (INIS)

    In recent years, there has been considerable discussion on the field called neutrino astronomy which represents exciting prospect in that it deals with the radiations which are distinct from electromagnetic spectra. Because of the unique, enormously long interaction mean free path of neutrinos, this field can in principle give extremely valuable complementary information about the universe, in particular about the conditions in the core of the sun and the energy balance and extent of the galaxy. Remarkable difference is observed when outlining of the development of neutrino astronomy is attempted in a manner similar to that for radio astronomy. The development on solar neutrinos, calculation of solar neutrino flux, solar neutrino search experiments, efforts to resolve the discrepancy between theory and experiment concerning the neutrinos from the sun, chemistry consideration, nuclear physics problems, astrophysical calculation, neutrino physics and other physical accomplishments are reviewed in the report. (Iwase, T.)

  20. Pseudonoise (PN) synchronization of data system with derivation of clock frequency from received signal for clocking receiver PN generator

    Science.gov (United States)

    Couvillon, L. A., Jr. (Inventor)

    1968-01-01

    A digital communicating system for automatically synchronizing signals for data detection is described. The systems consists of biphase modulating a subcarrier frequency by the binary data and transmitting a carrier phase modulated by this signal to a receiver, where coherent phase detection is employed to recover the subcarrier. Data detection is achieved by providing, in the receiver, a demodulated reference which is in synchronism with the unmodulated subcarrier in transmitting system. The output of the detector is passed through a matched filter where the signal is integrated over a bit period. As a result, random noise components are averaged out, so that the probability of detecting the correct data transmitted is maximized.

  1. Astronomy Allies

    Science.gov (United States)

    Flewelling, Heather; Alatalo, Katherine A.

    2016-01-01

    Imagine you are a grad student, at your first conference, and a prominent senior scientist shows interest in your work, and he makes things get way too personal? What would you do? Would you report it? Or would you decide, after a few other instances of harassment, that maybe you shouldn't pursue astronomy? Harassment is under-reported, the policies can be difficult to understand or hard to find, and it can be very intimidating as a young scientist to report it to the proper individuals. The Astronomy Allies Program is designed to help you with these sorts of problems. We are a group of volunteers that will help by doing the following: provide safe walks home during the conference, someone to talk to confidentially, as an intervener, as a resource to report harassment. The Allies are a diverse group of scientists committed to acting as mentors, advocates, and liaisons. The Winter 2015 AAS meeting was the first meeting that had Astronomy Allies, and Astronomy Allies provided a website for information, as well as a twitter, email, and phone number for anyone who needs our help or would like more information. We posted about the Astronomy Allies on the Women In Astronomy blog, and this program resonates with many people: either they want to help, or they have experienced harassment in the past and don't want to see it in the future. Harassment may not happen to most conference participants, but it's wrong, it's against the AAS anti-harassment policy ( http://aas.org/policies/anti-harassment-policy ), it can be very damaging, and if it happens to even one person, that is unacceptable. We intend to improve the culture at conferences to make it so that harassers feel they can't get away with their unprofessional behavior.

  2. Early Astronomy

    Science.gov (United States)

    Thurston, Hugh

    The earliest investigations that we can relate to what is now science are observations of the sky: Astronomy. The earliest written records of every civilization we know of - from China, Egypt, the Tigris-Euphrates and Indus valleys, Central America, the Andes, and so forth - all contain at least some astronomical texts. There are in addition monuments and artifacts that show a clear interest in astronomy, such as Stonehenge and rock paintings, from cultures that left no written records. The interest in celestial phenomena contributed to the development of Babylonian arithmetic and Greek geometry.

  3. Specification of a NAVSTAR Global Positioning System (GPS) receiver for a differential GPS ground system

    Science.gov (United States)

    Mccall, D. L.; Turner, R. N.

    1984-01-01

    One step towards the successful completion of a functional ground unit for the Differential Global Positioning System (DGPS) will be in choosing a currently available GPS receiver that will accurately measure the propagation times of the satellite signals and have the capability to be electrically interfaced with and controlled by a Digital Equipment Corporation (DEC) PDP-11/34A computer. The minimum requirements and characteristics of a NAVSTAR Global Positioning System (GPS) receiver are described. The specific technical specifications addressed include data accuracies and resolutions, receiver interface/external control, enclosure dimensions and mounting requirements, receiver operation, and environmental specifications.

  4. Rescuing Middle School Astronomy

    Science.gov (United States)

    Mayo, L. A.; Janney, D.

    2010-12-01

    There is a crisis in education at the middle school level (Spellings, 2006). Recent studies point to large disparities in middle school performance in schools with high minority populations. The largest disparities exist in areas of math and science. Astronomy has a universal appeal for K-12 students but is rarely taught at the middle school level. When it is taught at all it is usually taught in isolation with few references in other classes such as other sciences (e.g. physics, biology, and chemistry), math, history, geography, music, art, or English. The problem is greatest in our most challenged school districts. With scores in reading and math below national averages in these schools and with most state achievement tests ignoring subjects like astronomy, there is little room in the school day to teach about the world outside our atmosphere. Add to this the exceedingly minimal training and education in astronomy that most middle school teachers have and it is a rare school that includes any astronomy teaching at all. In this presentation, we show how to develop and offer an astronomy education training program for middle school teachers encompassing a wide range of educational disciplines that are frequently taught at the middle school level. The prototype for this program was developed and launched in two of the most challenged and diverse school systems in the country; D.C. Public Schools, and Montgomery County (MD) Public Schools.

  5. Using Visual Assessments and Tutorials to Teach Solar System Concepts in Introductory Astronomy

    Science.gov (United States)

    LoPresto, Michael C.

    2010-01-01

    Visual assessments and tutorials are instruments that rely on student construction and/or examination of pictures and/or diagrams rather than multiple choice and/or short answer questions. Being a very visual subject, astronomy lends itself to assessments and tutorials of this type. What follows is a report on the results of the use of visual…

  6. Measuring NIR Atmospheric Extinction Using a Global Positioning System Receiver

    CERN Document Server

    Blake, Cullen H

    2011-01-01

    Modeling molecular absorption by Earth's atmosphere is important for a wide range of astronomical observations, including broadband NIR photometry and high-resolution NIR spectroscopy. Using a line-by-line radiative transfer approach, we calculate theoretical transmission spectra in the deep red optical (700 to 1050 nm) for Apache Point Observatory. In this region the spectrum is dominated by H2O, which is known to be highly variable in concentration on short timescales. We fit our telluric models to high-resolution observations of A stars and estimate the relative optical depth of H2O absorption under a wide range of observing conditions. We compare these optical depth estimates to simultaneous measurements of Precipitable Water Vapor (PWV) based on data from a Global Positioning System (GPS) receiver located at Apache Point. We find that measured PWV correlates strongly with the scaling of H2O absorption lines in our spectra, indicating that GPS-based PWV measurements combined with atmospheric models may be...

  7. Building a Successful Teachers' Workshop in Astronomy & Astrophysics

    Science.gov (United States)

    Smecker-Hane, T. A.; Thornton, C. E.

    2005-12-01

    We discuss the Teachers' Workshop in Astronomy & Astrophysics, a 2-day long summer workshop we designed to aid K-12 grade teachers in incorporating astronomy and astrophysics into their curricula. These workshops are part of a faculty-led outreach program entitled Outreach in Astronomy & Astrophysics with the UCI Observatory, funded by an NSF FOCUS grant to the University of California, Irvine. Approximately 20 teachers from the Compton, Newport/Mesa and Santa Ana Unified School Districts attend each workshop. Our teachers realize that astronomy captures the imagination of their students, and thus lessons in astronomy can very effectively convey a number of challenging math and science concepts. Our workshop is designed to give teachers the content and instruction needed to achieve that goal. Because only a small fraction of teachers have taken a college astronomy course, an important component of the workshop is lectures on: (1) the motion of objects in the night sky, moon phases and the seasons, (2) the solar system, (3) the physics of light, and (4) interesting applications such as searching for planets around other stars and charting the expansion history of the Universe. The second important component of the workshop is the kit of material each teacher receives, which includes a introductory astronomy textbook, planetarium software, and the ASP's "Universe at Your Fingertips" and "More Universe at Your Fingertips", etc.. The latter two books give teachers many examples of creative hands-on activities and experiments they can do with their classes and instruction on how to build a coherent curriculum for their particular grade level. We also introduce teachers to Contemporary Laboratory Exercises in Astronomy (CLEA), a suite of computer lab exercises that can be used effectively in high school physics classes. For more information, see http://www.physics.uci.edu/%7Eobservat/#e&o. Funding provided by NSF grant EHR-0227202 (PI: Ronald Stern).

  8. Advanced Amateur Astronomy

    Science.gov (United States)

    North, Gerald

    This book is for amateur astronomers and telescope users who want to move beyond elementary stargazing to more challenging projects. Written by an accomplished amateur astronomer, this indispensable guide to more advanced work is packed with information and lucid explanations. The first section of the book sets out the fundamental principles of practical astronomy, with chapters on telescope optics, the atmosphere, telescope hardware, astrophotography, and electronic imaging. This knowledge is then applied to the full range of celestial bodies accessible by telescope: the solar system, stars and galaxies. For those users who want to move to even greater challenges, chapters on photometry, spectroscopy and radio astronomy bring observational astronomy to a level where data of real scientific value can be acquired.

  9. Extragalactic astronomy

    International Nuclear Information System (INIS)

    This book condenses the author's yearly semester lectures on 'Extra galactic Astronomy' held almost without interruption over two decades at Cordoba University for students of Astronomy. After a first chapter on Morphology and Classification of galaxies, the second gives most of the basic information about normal galaxies as individuals. Active galaxies are described in chapter III whilst chapter IV deals with the mutual relationship between galaxies and their environment. The Scale of distance is considered in chapter V. Distance indicators are introduced and several conflicting viewpoints of different schools are presented. Chapter VI deals with Cosmology, just to give the necessary elements for chapter VII where the relation between gravitational instability and galaxy formation is discussed. Chapter VIII is an appendix containing additional notes. (Auth.)

  10. Grassroots Astronomy

    Science.gov (United States)

    Marvel, Kevin B.

    Congress has a large impact on the amount and quality of astronomical research that takes place in the United States. By funding NASA and NSF, as well as other agencies such as the Department of Education and the Department of Defense, the Federal Government enables U.S. astronomers to perform cutting edge research. However, Congress makes decisions based on input from citizens. It the citizens are silent on an issue, Congress does not know it exists. Last summer the U.S.amatuer community rallied in support of professional research, resulting in a healthy budget for both NASA and NSF astronomy research. I will present a summary of how the funding process works and how and why amateurs can and should help ensure continued research funding for U.S. astronomy.

  11. Conceptual design of advanced central receiver power systems sodium-cooled receiver concept. Volume 1. Executive summary. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-06-01

    The conceptual design of an advanced central receiver power system using liquid sodium as a heat transport medium has been completed by a team consisting of the Energy Systems Group (prime contractor), McDonnell Douglas, Stearns-Roger, The University of Houston, and Salt River Project. The purpose of this study was to determine the technical and economic advantages of this concept for commercial-scale power plants. This final report covers all tasks of the project. These tasks were as follows: (1) review and analysis of preliminary specification; (2) parametric analysis; (3) select commercial configuration; (4) commercial plant conceptual design; (5) assessment of commercial plant; (6) advanced central receiver power system development plan; (7) program plan; (8) reports and data; (9) program management; and (10) safety analysis. A programmatic overview of the accomplishments of this program is given. The 100-MW conceptual commercial plant, the 281-MW optimum plant, and the 10-MW pilot plant are described. (WHK)

  12. Infrared astronomy

    International Nuclear Information System (INIS)

    This volume contains lectures describing the important achievements in infrared astronomy. The topics included are galactic infrared sources and their role in star formation, the nature of the interstellar medium and galactic structure, the interpretation of infrared, optical and radio observations of extra-galactic sources and their role in the origin and structure of the universe, instrumental techniques and a review of future space observations. (C.F.)

  13. Star Formation and Exoplanetary Systems in the National Science Olympiad Astronomy Event for High School Students

    Science.gov (United States)

    Komacek, Thaddeus D.; Young, Donna; Schroeder, Dustin M.; Van Hecke, Mark A.

    2014-11-01

    Science Olympiad is one of the nation’s largest secondary school science competitions, reaching over 240,000 students on more than 6,000 teams. The competition covers various aspects of science and technology, exposing students to a variety of career options in STEM. 9 of Science Olympiad’s 46 events (with 23 for both middle and high school) have a focus on Earth and Space Science, including process skills and knowledge of a variety of subjects, including: Astrophysics, Planetary Sciences, Oceanography, Meteorology, Remote Sensing, and Geologic Mapping, among others. The Astronomy event is held for students from 9th - 12th grade, and covers topics based upon stellar evolution and/or galactic astronomy. For the 2014-2015 competition season, Astronomy will focus on star formation and exoplanets in concert with stellar evolution, bringing recent and groundbreaking research to light for young potential astronomers and planetary scientists. The event tests students on their “understanding of the basic concepts of mathematics and physics relating to stellar evolution and star and planet formation,” including qualitative responses, DS9 image analysis, and quantitative problem solving. We invite any members of the exoplanet and star formation communities that are interested in developing event materials to contact the National event supervisors, Donna Young (donna@aavso.org) and Tad Komacek (tkomacek@lpl.arizona.edu). We also encourage you to contact your local regional or state Science Olympiad tournament directors to help supervise events and run competitions in your area.

  14. Infrared Astronomy

    Science.gov (United States)

    Mampaso, A.; Prieto, M.; Sánchez, F.

    2004-01-01

    What do we understand of the birth and death of stars? What is the nature of the tiny dust grains that permeate our Galaxy and other galaxies? And how likely is the existence of brown dwarfs, extrasolar planets or other sub-stellar mass objects? These are just a few of the questions that can now be addressed in a new era of infrared observations. IR astronomy has been revolutionised over the past few years by the widespread availability of large, very sensitive IR arrays and the success of IR satellites (IRAS in particular). Several IR space missions due for launch over the next few years promise an exciting future too. For these reasons, the IV Canary Islands Winter School of Astrophysics was dedicated to this burgeoning field. Its primary goal was to introduce graduate students and researchers from other areas to the important new observations and physical ideas that are emerging in this wide-ranging field of research. Lectures from nine leading researchers, renowned for their teaching abilities, are gathered in this volume. These nine chapters provide an excellent introduction as well as a thorough and up-to-date review of developments - essential reading for graduate students entering IR astronomy, and professionals from other areas who realise the importance that IR astronomy may have on their research.

  15. Elimination of electromagnetic interference to receivers and sensitive equipment generated by switching systems

    OpenAIRE

    Stelioudakis, Emmanuel

    1994-01-01

    Approved for public release, distribution unlimited Recently installed equipment in naval receiving sites such as digital telephone switching systems, uninterruptible power supplies, laser printers etc., induce Electromagnetic Interference (EMI) into recetver systems, thus limiting the performance of the receiving site. EMI is injected into receiver systems by conducted, inductive and capacitive paths associated with poor compartment shieldi...

  16. The Astronomy of Africa's Health Systems Literature During the MDG Era: Where Are the Systems Clusters?

    Science.gov (United States)

    Phillips, James F; Sheff, Mallory; Boyer, Christopher B

    2015-09-01

    Growing international concern about the need for improved health systems in Africa has catalyzed an expansion of the health systems literature. This review applies a bibliometric procedure to analyze the acceleration of scientific writing on this theme. We focus on research published during the Millennium Development Goal (MDG) era between 1990 and 2014, reporting findings from a systematic review of a database comprised of 17,655 articles about health systems themes from sub-Saharan African countries or subregions. Using bibliometric tools for co-word textual analysis, we analyzed the incidence and associations of keywords and phrases to generate and visualize topical foci on health systems as clusters of themes, much in the manner that astronomers represent groupings of stars as galaxies of celestial entities. The association of keywords defines their relative position, with the size of images weighted by the relative frequency of terms. Sets of associated keywords are arrayed as stars that cluster as "galaxies" of concepts in the knowledge universe represented by health systems research from sub-Saharan Africa. Results show that health systems research is dominated by literature on diseases and categorical systems research topics, rather than on systems science that cuts across diseases or specific systemic themes. Systems research is highly developed in South Africa but relatively uncommon elsewhere in the region. "Black holes" are identified by searching for terms in our keyword library related to terms in widely cited reviews of health systems. Results identify several themes that are unexpectedly uncommon in the country-specific health systems literature. This includes research on the processes of achieving systems change, the health impact of systems strengthening, processes that explain the systems determinants of health outcomes, or systematic study of organizational dysfunction and ways to improve system performance. Research quantifying the relationship

  17. Random time series in astronomy.

    Science.gov (United States)

    Vaughan, Simon

    2013-02-13

    Progress in astronomy comes from interpreting the signals encoded in the light received from distant objects: the distribution of light over the sky (images), over photon wavelength (spectrum), over polarization angle and over time (usually called light curves by astronomers). In the time domain, we see transient events such as supernovae, gamma-ray bursts and other powerful explosions; we see periodic phenomena such as the orbits of planets around nearby stars, radio pulsars and pulsations of stars in nearby galaxies; and we see persistent aperiodic variations ('noise') from powerful systems such as accreting black holes. I review just a few of the recent and future challenges in the burgeoning area of time domain astrophysics, with particular attention to persistently variable sources, the recovery of reliable noise power spectra from sparsely sampled time series, higher order properties of accreting black holes, and time delays and correlations in multi-variate time series. PMID:23277606

  18. Random time series in Astronomy

    CERN Document Server

    Vaughan, Simon

    2013-01-01

    Progress in astronomy comes from interpreting the signals encoded in the light received from distant objects: the distribution of light over the sky (images), over photon wavelength (spectrum), over polarization angle, and over time (usually called light curves by astronomers). In the time domain we see transient events such as supernovae, gamma-ray bursts, and other powerful explosions; we see periodic phenomena such as the orbits of planets around nearby stars, radio pulsars, and pulsations of stars in nearby galaxies; and persistent aperiodic variations (`noise') from powerful systems like accreting black holes. I review just a few of the recent and future challenges in the burgeoning area of Time Domain Astrophysics, with particular attention to persistently variable sources, the recovery of reliable noise power spectra from sparsely sampled time series, higher-order properties of accreting black holes, and time delays and correlations in multivariate time series.

  19. Random time series in astronomy.

    Science.gov (United States)

    Vaughan, Simon

    2013-02-13

    Progress in astronomy comes from interpreting the signals encoded in the light received from distant objects: the distribution of light over the sky (images), over photon wavelength (spectrum), over polarization angle and over time (usually called light curves by astronomers). In the time domain, we see transient events such as supernovae, gamma-ray bursts and other powerful explosions; we see periodic phenomena such as the orbits of planets around nearby stars, radio pulsars and pulsations of stars in nearby galaxies; and we see persistent aperiodic variations ('noise') from powerful systems such as accreting black holes. I review just a few of the recent and future challenges in the burgeoning area of time domain astrophysics, with particular attention to persistently variable sources, the recovery of reliable noise power spectra from sparsely sampled time series, higher order properties of accreting black holes, and time delays and correlations in multi-variate time series.

  20. Learning Astronomy by Doing Astronomy

    Science.gov (United States)

    Percy, J. R.

    2006-08-01

    In the modern science curriculum, students should learn science knowledge or "facts"; they should develop science skills, strategies, and habits of mind; they should understand the applications of science to technology, society, and the environment; and they should cultivate appropriate attitudes toward science. While science knowledge may be taught through traditional lecture-and-textbook methods, theories of learning (and extensive experience) show that other aspects of the curriculum are best taught by doing science -- not just hands-on activities, but "minds-on" engagement. That means more than the usual "cookbook" activities in which students use a predetermined procedure to achieve a predetermined result. The activities should be "authentic"; they should mirror the actual scientific process. In this presentation, I will describe several ways to include science processes within astronomy courses at the middle school, high school, and introductory university level. Among other things, I will discuss: topics that reflect cultural diversity and "the nature of science"; strategies for developing science process skills through projects and other practical work; activities based on those developed and carried out by amateur astronomers; topics and activities suitable for technical-level courses (we refer to them as "applied" in my province); projects for astronomy clubs and science fairs; and topics that expose students to astronomy research within lecture courses.

  1. Salt Repository Project transportation system interface requirements: Transportation system/repository receiving facility interface requirements

    International Nuclear Information System (INIS)

    This report is a preliminary review of the interface between the transportation system and the repository receiving facility for a nuclear waste mined geologic disposal system in salt. Criteria for generic cask and facility designs are developed. These criteria are derived by examining the interfaces that occur as a result of the operations needed to receive nuclear waste at a repository. These criteria provide the basis for design of a safe, operable, practical nuclear waste receiving facility. The processing functions required to move the shipping unit from the gate into the unloading area and back to the gate for dispatch are described. Criteria for a generic receiving facility are discussed but no specific facility design is presented or evaluated. The criteria are stated in general terms to allow application to a wide variety of cask and facility designs. 9 refs., 6 figs., 4 tabs

  2. Receive channel architecture and transmission system for digital array radar

    OpenAIRE

    Yong, Yoke Chuang

    2005-01-01

    An â opportunistic arrayâ is a new digital antenna concept where phased array elements are placed at available open areas over the entire length of the platform. The elements are self-standing transmit-receive modules that require no hardwire connections other than prime power. All synchronization signals and data are passed wirelessly between the elements and a central signal processor. An opportunistic array that is integrated into the hull or superstructure of the warship is called an â...

  3. The New Astronomy

    Science.gov (United States)

    Henbest, Nigel; Marten, Michael

    1996-08-01

    There's more to the Universe than meets the eye. In a marvelous review of multi-wavelength astronomy, The New Astronomy compares traditional optical images to infrared, ultraviolet, radio, and X-ray astronomical observations of a staggering variety of cosmic objects. With over 300 photographs and images obtained by telescopes and detectors operating at different wavelengths, the authors present startlingly different views of the solar system, stars, galaxies and, in this new edition, Halley's Comet and Supernova 1987A. Specially processed by astronomers worldwide, these images reveal in spectacular detail otherwise invisible events such as starbirth, stardeath, and distant quasar eruptions. Emphasizing the physical processes that produce astronomical radiation, they explain how the observations have expanded our existing knowledge and provided new discoveries. They also describe the new techniques in nontechnical language. By giving equal weight to observations at all wavelengths, this book corrects the bias toward optical astronomy and objectively presents all views of the Universe. It will appeal to everyone interested in the mysteries of astronomy. Nigel Henbest and Michael Marten previously collaborated (along with Heather Couper) on The Guide to the Galaxy (CUP, 1994).

  4. Radio astronomy

    CERN Document Server

    Alder, Berni

    1975-01-01

    Methods in Computational Physics, Volume 14: Radio Astronomy is devoted to the role of the digital computer both as a control device and as a calculator in addressing problems related to galactic radio noise. This volume contains four chapters and begins with a technical description of the hardware and the special data-handling problems of using radioheliography, with an emphasis on a selection of observational results obtained with the Culgoora radioheliograph and their significance to solar physics and to astrophysics in general. The subsequent chapter examines interstellar dispersion, i

  5. Elementary astronomy

    Science.gov (United States)

    Fierro, J.

    2006-08-01

    In developing nations such as Mexico, basic science education has scarcely improved. There are multiple reasons for this problem; they include poor teacher training and curricula that are not challenging for students. I shall suggest ways in which astronomy can be used to improve basic education, it is so attractive that it can be employed to teach how to read and write, learn a second language, mathematics, physics, as well as geography. If third world nations do not teach science in an adequate way, they will be in serious problems when they will try to achieve a better standard of living for their population. I shall also address informal education, it is by this means that most adults learn and keep up to date with subjects that are not their specialty. If we provide good outreach programs in developing nations we can aid adult training; astronomy is ideal since it is particularly multidisciplinary. In particular radio and television programs are useful for popularization since they reach such wide audiences.

  6. Evaluation of Veda, Inc. , central receiver solar collection system concept

    Energy Technology Data Exchange (ETDEWEB)

    Ator, J.

    1981-08-01

    The Unified Heliostat Array (UHA) is a geometrical heliostat field layout with rows of mirrors placed at various levels on terraces. The Veda Industrial Heliostat (VIH) is a toroidal segment mirror mounted on an equatorial mount. These two concepts are evaluated to assess the credibility of the optical designs and the validity of UHA and VIH performance estimates, to determine what the distinctive features embodied in UHA AND VIH concepts offer that more conventional central receiver technologies do not, and to determine where the UHA and VIH concepts might be most applicable in DOE's Solar Thermal Program. The UHA area efficiency, flux density distribution, and beam safety are evaluated, and the feasibility of using a secondary mirror and the potential for special applications are assessed. The optical design, equatorial mount, and manufacturability of the VIH are evaluated. (LEW)

  7. Design and verification of focal plane assembly thermal control system of one space-based astronomy telescope

    Science.gov (United States)

    Yang, Wen-gang; Fan, Xue-wu; Wang, Chen-jie; Wang, Ying-hao; Feng, Liang-jie; Du, Yun-fei; Ren, Guo-rui; Wang, Wei; Li, Chuang; Gao, Wei

    2015-10-01

    One space-based astronomy telescope will observe astronomy objects whose brightness should be lower than 23th magnitude. To ensure the telescope performance, very low system noise requirements need extreme low CCD operating temperature (lower than -65°C). Because the satellite will be launched in a low earth orbit, inevitable space external heat fluxes will result in a high radiator sink temperature (higher than -65°C). Only passive measures can't meet the focal plane cooling specification and active cooling technologies must be utilized. Based on detailed analysis on thermal environment of the telescope and thermal characteristics of focal plane assembly (FPA), active cooling system which is based on thermo-electric cooler (TEC) and heat rejection system (HRS) which is based on flexible heat pipe and radiator have been designed. Power consumption of TECs is dependent on the heat pumped requirements and its hot side temperature. Heat rejection capability of HRS is mainly dependent on the radiator size and temperature. To compromise TEC power consumption and the radiator size requirement, thermal design of FPA must be optimized. Parasitic heat loads on the detector is minimized to reduce the heat pumped demands of TECs and its power consumption. Thermal resistance of heat rejection system is minimized to reject the heat dissipation of TECs from the hot side to the radiator efficiently. The size and surface coating of radiator are optimized to compromise heat reject ion requirements and system constraints. Based on above work, transient thermal analysis of FPA is performed. FPA prototype model has been developed and thermal vacuum/balance test has been accomplished. From the test, temperature of key parts and working parameters of TECs in extreme cases have been acquired. Test results show that CCD can be controlled below -65°C and all parts worked well during the test. All of these verified the thermal design of FPA and some lessons will be presented in this

  8. TeachAstronomy.com - Digitizing Astronomy Resources

    Science.gov (United States)

    Hardegree-Ullman, Kevin; Impey, C. D.; Austin, C.; Patikkal, A.; Paul, M.; Ganesan, N.

    2013-06-01

    Teach Astronomy—a new, free online resource—can be used as a teaching tool in non-science major introductory college level astronomy courses, and as a reference guide for casual learners and hobbyists. Digital content available on Teach Astronomy includes: a comprehensive introductory astronomy textbook by Chris Impey, Wikipedia astronomy articles, images from Astronomy Picture of the Day archives and (new) AstroPix database, two to three minute topical video clips by Chris Impey, podcasts from 365 Days of Astronomy archives, and an RSS feed of astronomy news from Science Daily. Teach Astronomy features an original technology called the Wikimap to cluster, display, and navigate site search results. Development of Teach Astronomy was motivated by steep increases in textbook prices, the rapid adoption of digital resources by students and the public, and the modern capabilities of digital technology. This past spring semester Teach Astronomy was used as content supplement to lectures in a massive, open, online course (MOOC) taught by Chris Impey. Usage of Teach Astronomy has been steadily growing since its initial release in August of 2012. The site has users in all corners of the country and is being used as a primary teaching tool in at least four states.

  9. Modelling of Transmitter & Receiver for VSAT Communication System

    Directory of Open Access Journals (Sweden)

    Sanjida Sharmin Mohona

    2015-02-01

    Full Text Available The Satellite communication is an essential part of telecommunication systems which carrying large amount of data (internet, e-mail and telephone traffic in addition to TV signals. Very small aperture terminal (VSAT is widely used for these purposes. This paper aims to provide the framework of VSAT technology in the evolving context of satellite communications in terms of network configuration, services, economics and operational aspects. This paper presents the modelling and simulation aspects of communication blocks of VSAT which can be used in different types of network topology and also includes the numerical results simulated by MATLAB.

  10. Receiver for 6-cm Polarization Observation Starts Working

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ A 6-cm receiving system with a polarimeter, made by engineers of German MaxPlanck-Institute for Radioastronomy, has been installed to the 25 radio telescope in Urumqi, the capital of western China's Xinjiang Uygur Autonomous Region. The new instrument for Sino-German cooperation on radio astronomy will enable Chinese astronomers to measure the polarization of radio sources for the first time.

  11. Low-profile heliostat design for solar central receiver systems

    Science.gov (United States)

    Fourakis, E.; Severson, A. M.

    1977-01-01

    Heliostat designs intended to reduce costs and the effect of adverse wind loads on the devices were developed. Included was the low-profile heliostat consisting of a stiff frame with sectional focusing reflectors coupled together to turn as a unit. The entire frame is arranged to turn angularly about a center point. The ability of the heliostat to rotate about both the vertical and horizontal axes permits a central computer control system to continuously aim the sun's reflection onto a selected target. An engineering model of the basic device was built and is being tested. Control and mirror parameters, such as roughness and need for fine aiming, are being studied. The fabrication of these prototypes is in process. The model was also designed to test mirror focusing techniques, heliostat geometry, mechanical functioning, and tracking control. The model can be easily relocated to test mirror imaging on a tower from various directions. In addition to steering and aiming studies, the tests include the effects of temperature changes, wind gusting and weathering. The results of economic studies on this heliostat are also presented.

  12. Syllabus Computer in Astronomy

    Science.gov (United States)

    Hojaev, Alisher S.

    2015-08-01

    One of the most important and actual subjects and training courses in the curricula for undergraduate level students at the National university of Uzbekistan is ‘Computer Methods in Astronomy’. It covers two semesters and includes both lecture and practice classes. Based on the long term experience we prepared the tutorial for students which contain the description of modern computer applications in astronomy.The main directions of computer application in field of astronomy briefly as follows:1) Automating the process of observation, data acquisition and processing2) Create and store databases (the results of observations, experiments and theoretical calculations) their generalization, classification and cataloging, working with large databases3) The decisions of the theoretical problems (physical modeling, mathematical modeling of astronomical objects and phenomena, derivation of model parameters to obtain a solution of the corresponding equations, numerical simulations), appropriate software creation4) The utilization in the educational process (e-text books, presentations, virtual labs, remote education, testing), amateur astronomy and popularization of the science5) The use as a means of communication and data transfer, research result presenting and dissemination (web-journals), the creation of a virtual information system (local and global computer networks).During the classes the special attention is drawn on the practical training and individual work of students including the independent one.

  13. Binocular astronomy

    CERN Document Server

    Tonkin, Stephen

    2014-01-01

    Binoculars have, for many, long been regarded as an “entry level” observational tool, and relatively few have used them as a serious observing instrument. This is changing! Many people appreciate the relative comfort of two-eyed observing, but those who use binoculars come to realize that they offer more than comfort. The view of the stars is more aesthetically pleasing and therefore binocular observers tend to observe more frequently and for longer periods. Binocular Astronomy, 2nd Edition, extends its coverage of small and medium binoculars to large and giant (i.e., up to 300mm aperture) binoculars and also binoviewers, which brings the work into the realm of serious observing instruments. Additionally, it goes far deeper into the varying optical characteristics of binoculars, giving newcomers and advanced astronomers the information needed to make informed choices on purchasing a pair. It also covers relevant aspects of the physiology of binocular (as in “both eyes”) observation. The first edition ...

  14. Teaching and Learning Astronomy

    Science.gov (United States)

    Pasachoff, Jay; Percy, John

    2009-07-01

    Preface; Part I. Astronomy in the Curriculum Around the World: Preface; 1. Why astronomy is useful and should be included in the school curriculum John R. Percy; 2. Astronomy and mathematics education Rosa M. Ros; 3. Astronomy in the curriculum around the world; 4. Engaging gifted science students through astronomy Robert Hollow; 5. Poster highlights: astronomy in the curriculum around the world; Part II. Astronomy Education Research: Preface; 6. Astronomy education research down under John M. Broadfoot and Ian S. Ginns; 7. A contemporary review of K-16 astronomy education research Janelle M. Bailey and Timothy F. Slater; 8. Implementing astronomy education research Leonarda Fucili; 9. The Astronomy Education Review: report on a new journal Sidney C. Wolff and Andrew Fraknoi; 10. Poster highlights: astronomy education research; Part III. Educating Students: Preface; 11. Textbooks for K-12 astronomy Jay M. Pasachoff; 12. Distance/internet astronomy education David H. McKinnon; 13. Educating students with robotic telescopes - open discussion; 14. Poster highlights - educating students; Part IV. Educating teachers: Preface; 15. Pre-service astronomy education of teachers Mary Kay Hemenway; 16. In-service education of teachers Michèle Gerbaldi; 17. Poster highlights: educating teachers; Part V. Astronomy and Pseudoscience: Preface; 18. Astronomy, pseudoscience and rational thinking Jayant V. Narlikar; 19. Astronomical pseudosciences in North America John R. Percy and Jay M. Pasachoff; Part VI. Astronomy and Culture: Preface; 20. Teaching astronomy in other cultures: archeoastronomy Julieta Fierro; 21. Poster highlights: astronomy and culture; Part VII. Astronomy in Developing Countries: Preface; 22. Astronomy Curriculum for developing countries Case Rijsdijk; 23. Science education resources for the developing countries James C. White II; Part VIII. Public Outreach in Astronomy: Preface; 24. What makes informal education programs successful? Nahide Craig and Isabel

  15. Reduced-complexity radio architectures for enhanced receive selection combining in multiuser diversity systems

    DEFF Research Database (Denmark)

    Tsakalaki, Elpiniki; Alrabadi, Osama; Papadias, Constantinos B.;

    2012-01-01

    this problem, we propose miniaturized switched beam receiver designs assisted by low-cost passive reflectors. Unlike conventional spatial receive diversity systems, the proposed angular diversity architectures occupy a small volume whereas the antenna system properties are optimized by controlling the strong...

  16. Innovation in Astronomy Education

    Science.gov (United States)

    Pasachoff, Jay M.; Ros, Rosa M.; Pasachoff, Naomi

    2013-01-01

    Preface; Part I. General Strategies for Effective Teaching: Introduction; 1. Main objectives of SpS2; 2. Learning astronomy by doing astronomy; 3. Hands-on Universe-Europe; 4. Life on Earth in the atmosphere of the Sun; 5. A model of teaching astronomy to pre-service teachers; 6. How to teach, learn about, and enjoy astronomy; 7. Clickers: a new teaching tool of exceptional promise; 8. Educational opportunities in pro-am collaboration; 9. Teaching history of astronomy to second-year engineering students; 10. Teaching the evolution of stellar and Milky Way concepts through the ages; 11. Educational efforts of the International Astronomical Union; 12. Astronomy in culture; 13. Light pollution: a tool for astronomy education; 14. Astronomy by distance learning; 15. Edible astronomy demonstrations; 16. Amateur astronomers as public outreach partners; 17. Does the Sun rotate around Earth or Earth rotate around the Sun?; 18. Using sounds and sonifications for astronomy outreach; 19. Teaching astronomy and the crisis in science education; 20. Astronomy for all as part of a general education; Poster abstracts; Part II. Connecting Astronomy with the Public: Introduction; 21. A status report from the Division XII working group; 22. Outreach using media; 23. Astronomy podcasting; 24. IAU's communication strategy, hands-on science communication, and the communication of the planet definition discussion; 25. Getting a word in edgeways: the survival of discourse in audiovisual astronomy; 26. Critical evaluation of the new Hall of Astronomy; 27. Revitalizing astronomy teaching through research on student understanding; Poster abstracts; Part III. Effective Use of Instruction and Information Technology: Introduction; 28. ESO's astronomy education program; 29. U.S. student astronomy research and remote observing projects; 30. Global network of autonomous observatories dedicated to student research; 31. Remote telescopes in education: report of an Australian study; 32. Visualizing

  17. Engineering satellite-based navigation and timing global navigation satellite systems, signals, and receivers

    CERN Document Server

    Betz, J

    2016-01-01

    This book describes the design and performance analysis of satnav systems, signals, and receivers. It also provides succinct descriptions and comparisons of all the world’s satnav systems. Its comprehensive and logical structure addresses all satnav signals and systems in operation and being developed. Engineering Satellite-Based Navigation and Timing: Global Navigation Satellite Systems, Signals, and Receivers provides the technical foundation for designing and analyzing satnav signals, systems, and receivers. Its contents and structure address all satnav systems and signals: legacy, modernized, and new. It combines qualitative information with detailed techniques and analyses, providing a comprehensive set of insights and engineering tools for this complex multidisciplinary field. Part I describes system and signal engineering including orbital mechanics and constellation design, signal design principles and underlying considerations, link budgets, qua tifying receiver performance in interference, and e...

  18. A Novel Iterative Receiver Based on Extrinsic Information Update for MIMO Systems

    Institute of Scientific and Technical Information of China (English)

    LIN Wen-feng; HE Chen

    2007-01-01

    A novel iterative receiver for multiple input multiple output (MIMO) systems was introduced.Its basis concept is that the reliability of extrinsic information will be strengthened with continuous iterations.Extrinsic information of present iteration is added with prior information of last iteration to obtain performance gain.The simulation results show that the improved iterative receiver can approach the 5th iteration performance of conventional soft interference cancellation (SIC)-minimum mean square error (MMSE) iterative receiver after the 2nd iteration with less computational complexity.Compared with conventional iterative receiver, the improved iterative receiver has 1dB performance gain at bit error rate (BER) of 10-5, with four transmit antennas and four receive antennas system.

  19. Performance of Turbo Interference Cancellation Receivers in Space-Time Block Coded DS-CDMA Systems

    Directory of Open Access Journals (Sweden)

    Emmanuel Oluremi Bejide

    2008-07-01

    Full Text Available We investigate the performance of turbo interference cancellation receivers in the space time block coded (STBC direct-sequence code division multiple access (DS-CDMA system. Depending on the concatenation scheme used, we divide these receivers into the partitioned approach (PA and the iterative approach (IA receivers. The performance of both the PA and IA receivers is evaluated in Rayleigh fading channels for the uplink scenario. Numerical results show that the MMSE front-end turbo space-time iterative approach receiver (IA effectively combats the mixture of MAI and intersymbol interference (ISI. To further investigate the possible achievable data rates in the turbo interference cancellation receivers, we introduce the puncturing of the turbo code through the use of rate compatible punctured turbo codes (RCPTCs. Simulation results suggest that combining interference cancellation, turbo decoding, STBC, and RCPTC can significantly improve the achievable data rates for a synchronous DS-CDMA system for the uplink in Rayleigh flat fading channels.

  20. Selected topics on data analysis in astronomy

    International Nuclear Information System (INIS)

    The contents of this book are: General Lectures Given at the Erice II Workshop on Data Analysis in Astronomy: Fundamentals in Data Analysis in Astronomy; Computational Techniques; Evolution of Architectures for Data Processing; Hardware for Graphics and Image Display; and Data Analysis Systems

  1. Practical astronomy with your calculator

    CERN Document Server

    Duffett-Smith, Peter

    1989-01-01

    Practical Astronomy with your Calculator, first published in 1979, has enjoyed immense success. The author's clear and easy to follow routines enable you to solve a variety of practical and recreational problems in astronomy using a scientific calculator. Mathematical complexity is kept firmly in the background, leaving just the elements necessary for swiftly making calculations. The major topics are: time, coordinate systems, the Sun, the planetary system, binary stars, the Moon, and eclipses. In the third edition there are entirely new sections on generalised coordinate transformations, nutr

  2. Random time series in Astronomy

    OpenAIRE

    Vaughan, Simon

    2013-01-01

    Progress in astronomy comes from interpreting the signals encoded in the light received from distant objects: the distribution of light over the sky (images), over photon wavelength (spectrum), over polarization angle, and over time (usually called light curves by astronomers). In the time domain we see transient events such as supernovae, gamma-ray bursts, and other powerful explosions; we see periodic phenomena such as the orbits of planets around nearby stars, radio pulsars, and pulsations...

  3. Discussion of mechanical design for pressured cavity-air-receiver in solar power tower system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zhilin; Zhang, Yaoming; Liu, Deyou; Wang, Jun; Liu, Wei [Hohai Univ., Nanjing (China). New Materials and Energy Sources Research and Exploitation Inst.

    2008-07-01

    In 2005, Hohai university and Nanjing Chunhui science and technology Ltd. of China, cooperating with Weizmann Institute of Science and EDIG Ltd. of Israel, built up a 70kWe solar power tower test plant in Nanjing, Jiangsu province, China, which was regarded as the first demonstration project to demonstrate the feasibility of solar power tower system in China. The system consists of heliostats field providing concentrated sunlight, a solar tower with a height of 33 meter, a pressured cavity-air-receiver transforming solar energy to thermal energy, a modified gas turbine adapting to solar power system, natural gas subsystem for solar-hybrid generation, cooling water subsystem for receiver and CPC, controlling subsystem for whole plant, et al. In this system, air acts as actuating medium and the system works in Brayton cycle. Testing results show that solar power tower system is feasible in China. To promote the development of solar powered gas turbine system and the pressured cavity-air-receiver technology in China, it is necessary to study the mechanical design for pressured Cavity-air-receiver. Mechanical design of pressured cavity-air-receiver is underway and some tentative principles for pressured cavity-air-receiver design, involving in power matching, thermal efficiency, material choosing, and equipment security and machining ability, are presented. At the same time, simplified method and process adapted to engineering application for the mechanical design of pressured cavity-air-receiver are discussed too. Furthermore, some design parameters and appearance of a test sample of pressured cavity-air-receiver designed in this way is shown. It is appealed that, in China, the research in this field should be intensified and independent knowledge patents for pivotal technological equipments such as receiver in solar power tower system should be formed. (orig.)

  4. An Approach to Calculate the Efficiency for an N-Receiver Wireless Power Transfer System

    Directory of Open Access Journals (Sweden)

    Thabat Thabet

    2015-09-01

    Full Text Available A wireless power transfer system with more than one receiver is a realistic proposition for charging multiple devices such as phones and a tablets. Therefore, it is necessary to consider systems with single transmitters and multiple receivers in terms of efficiency. Current offerings only consider single device charging systems. A problem encountered is the efficiency of one receiver can be affected by another because of the mutual inductance between them. In this paper, an efficiency calculation method is presented for a wireless power transfer system with one to N-receivers. The mutual inductance between coils is implicitly calculated for different spatial positions and verified by practical experimentation. The effect of changing parameters, such as resonant frequency, coil size and distance between coils, on the efficiency has been studied. A clarification of the special performance of a wireless power transfer system at a specific point has been presented.

  5. Astronomy in the City for Astronomy Education

    Science.gov (United States)

    Ros, Rosa Maria; García, Beatriz

    2015-08-01

    Astronomy is part of our culture. Astronomy cannot be isolated in a classroom, it has to be integrated in the normal life of teachers and students. “Astronomy in the city” is an important part of NASE (Network for Astronomy School Education). In each NASE course we introduce a “working group session” chaired by a local expert in cultural astronomy. The chair introduces several examples of astronomy in their city and after that, the participants have the opportunity to discuss and mention several similar examples. After this session all participants visit one or two sites proposed and introduced by the chair.After more than 5 years using this method we visited and discovered several examples of astronomy in the city:• Astronomy in ancient typical cloths• Archeological temples oriented according the Sun rise or set.• Petroglyphs with astronomical meaning.• Astronomy in monuments.• Sundials.• Oriented Colonial churches• Astronomy in SouvenirsIn any case, teachers and students discover that Astronomy is part of their everyday life. They can take into account the Sun's path when they park their car or when they take a bus "what is the best part in order to be seat in the shadow during the journey?" The result is motivation to go with “open eyes” when they are in the street and they try to get more and more information about their surroundings.The most significant characteristic of NASE is that the ”Local NASE Working Group” (LWG) in each country continues with astronomy activities using our materials and new materials created by them. These LWG are integrated by 6 to 8 teachers and professors that participated actively in NASE courses. They maintains alive the program and increases the number of students which can learn through our didactical proposal. There are more than 25 LWG that teach and organize activities on astronomy (education and/or communication) in about 20 countries.In summary, one of the main activities is to introduce local

  6. Astrology as Cultural Astronomy

    Science.gov (United States)

    Campion, Nicholas

    The practice of astrology can be traced in most if not all human societies, in most time periods. Astrology has prehistoric origins and flourishes in the modern world, where it may be understood as a form of ethnoastronomy - astronomy practiced by the people. The Western tradition, which originated in Mesopotamia and was developed in the Greek world, has been most studied by academics. However, India is also home to a tradition which has survived in a continuous lineage for 2,000 years. Complex systems of astrology also developed in China and Mesoamerica, while all other human societies appear to seek social and religious meaning in the stars.

  7. Astronomy. Internet site

    Science.gov (United States)

    Maksimenko, Anatoly Vasilievich

    The Internet site covers a wide area of actual astronomical topics, including 1) Astronomical News 2) Didactics of Astronomy 3) Space Research (Cosmonautics) 4) That's interesting 5) A Handbook of an astronomer 6) The Solar system 7) A Photogalery 8) Works of Schoolars 9) History of Astronomy The most important of them is the section concerning Space Research (Cosmonautics). This section covers a wide range of topics, beginning with very complete Illustrated History of Soviet Space research , the building of Soviet Rockets, a complete list of Cosmonauts with biographies, a list of all the flies. The author of the site concerns much ineterest to recent and extraordinary astronomiucal phenomena, such as Hazardous asteroids, Comets, Solar and Moon Eclipses, Meteorites, as well as to correct from the scientifical point of view interpretation of the extraordinary astronomical phenomena. The section concerning the Solar system is richly illustrated and give detailed explanations to Solar System evolution and actual state, explains many phenomena in the Solar system. THe Internet site is designed for schoolars as well as to amateur and professional astronomers.

  8. Impact of Aerosols on Atmospheric Attenuation Loss in Central Receiver Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, M.; Wagner, M. J.

    2011-08-01

    Atmospheric attenuation loss between the heliostat field and receiver has been recognized as a significant source of loss in Central Receiver Systems. In clear sky situations, extinction of Direct Normal Irradiance (DNI) is primarily by aerosols in the atmosphere. When aerosol loading is high close to the surface the attenuation loss between heliostat and receivers is significantly influenced by the amount of aerosols present on a particular day. This study relates measured DNI to aerosol optical depths close to the surface of the earth. The model developed in the paper uses only measured DNI to estimate the attenuation between heliostat and receiver in a central receiver system. The requirement that only a DNI measurement is available potentially makes the model a candidate for widespread use.

  9. High Sensitivity, Radiation Hard InGaAs LIDAR Receiver for Unmanned Aircraft Systems (UAS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has a requirement for a large-area, high-quantum-efficiency, high-throughput optical receiver for ground-, air-, and space-based LIDAR systems. A...

  10. Design and Construction of a New 1420 MHz Receiver System for a 12-meter Radio Telescope

    Science.gov (United States)

    Lemley, Cameron; Castelaz, M. W.

    2014-01-01

    During the summer of 2013, a new 1420 MHz receiver system was designed and constructed for the 12-meter radio telescope at the Pisgah Astronomical Research Institute (PARI). The new radio receiver system consists of a feedhorn (which is a duplicate of the feedhorn that is currently installed on PARI’s 4.6-meter radio telescope), a low-noise amplifier, a bandpass filter, a downconverter, a SpectraCyber 1420 MHz Hydrogen Line Spectrometer, CommScope CNT-600 braided coaxial cable, and a power supply. Each component was individually tested on the preexisting 4.6-meter radio telescope receiver system before being installed on the 12-meter telescope. This testing process revealed that the spectrometer that was intended for use in the new 12-meter receiver system would require 12-bit software, which was acquired soon thereafter. The new receiver system was then assembled on a rolling cart for further testing. After the 1420 MHz receiver system was moved outside, it successfully detected its first extraterrestrial radio signal. The next step of this project was the installation of the feedhorn at the focus of the 12-meter parabolic reflector and the mounting of the additional receiver system components inside the radio frequency (RF) room of the 12-meter telescope. Following its installation on the 12-meter telescope, the new receiver system was connected to the PARI network via ethernet using a device called a SitePlayer Telnet. The 12-meter telescope was focused by taking continuum scans of Virgo A during its meridian crossing. The positioning of the feedhorn had to be adjusted several times before the new radio receiver system was precisely focused. After focusing the 12-meter telescope, spectra were taken of both the Orion Nebula and the Crab Nebula to test the abilities of the new 1420 MHz receiver system. As a final test of both the angular resolution and time resolution of the new radio receiver system, the 12-meter telescope was used to observe the pulsar PSR J

  11. Astronomy and Politics

    Science.gov (United States)

    Steele, John M.

    The relationship between astronomy and politics is a complex but important part of understanding the practice of astronomy throughout history. This chapter explores some of the ways that astronomy, astrology, and politics have interacted, placing particular focus on the way that astronomy and astrology have been used for political purposes by both people in power and people who wish to influence a ruler's policy. Also discussed are the effects that politics has had on the development of astronomy and, in particular, upon the recording and preservation of astronomical knowledge.

  12. Computers in Astronomy: Astronomy on an Apple Macintosh.

    Science.gov (United States)

    Mosley, John E.

    1987-01-01

    Presents a review of computer programs written for the Apple Macintosh computer that teach astronomy. Reviews general programs, along with some which deal more specifically with sky travel, star charting, the solar system, Halley's Comet, and stargazing. Includes the name and address of each producer. (TW)

  13. Music and Astronomy Under the Stars 2009

    Science.gov (United States)

    Lubowich, D.

    2010-08-01

    Bring telescopes to where the people are! Music and Astronomy Under the Stars is a three-year NASA-funded astronomy outreach program at community parks during and after music concerts and outdoor family events—such as a Halloween Stars-Spooky Garden Walk. While there have been many astronomy outreach activities and telescope observations at city sidewalks and parks, this program targets a completely different audience: music lovers who are attending summer concerts held in community parks. These music lovers who may never have visited a science museum, planetarium, or star party are exposed to telescope observations and astronomy information with no additional travel costs. Music and Astronomy Under the Stars increased awareness, engagement, and interest in astronomy at classical, pop, rock, and ethnic music concerts. This program includes solar observing before the concerts, telescope observations including a live image projection system, an astronomical video presentation, and astronomy banners/posters. Approximately 500-16,000 people attended each event and 25% to 50% of the people at each event participated in the astronomy program. This program also reached underrepresented and underserved groups (women, minorities, older adults). The target audience (Nassau and Suffolk Counties, New York) is 2,900,000 people, which is larger than combined population of Atlanta, Boston, Denver, Minneapolis, and San Francisco. Although eleven events were planned in 2009, two were canceled due to rain and our largest event, the NY Philharmonic in the Park (attended by 67,000 people in 2008), was cancelled for financial reasons. Our largest event in 2009 was the Tanglewood Music Festival, Lenox MA, attended by 16,000 people where over 5000 people participated in astronomy activities. The Amateur Observers' Society of New York assisted with the NY concerts and the Springfield STARS astronomy club assisted at Tanglewood. In 2009 over 15,000 people participated in astronomy

  14. Advances in astronomy and astrophysics

    CERN Document Server

    Kopal, Zdenek

    1962-01-01

    Advances in Astronomy and Astrophysics, Volume 1 brings together numerous research works on different aspects of astronomy and astrophysics. This book is divided into five chapters and begins with an observational summary of the shock-wave theory of novae. The subsequent chapter provides the properties and problems of T tauri stars and related objects. These topics are followed by discussions on the structure and origin of meteorites and cosmic dust, as well as the models for evaluation of mass distribution in oblate stellar systems. The final chapter describes the methods of polarization mea

  15. Astronomy for teachers in Mexico

    Science.gov (United States)

    Fierro, J.

    2006-08-01

    Mexico has added five more years of compulsory education to its national education system. In the past it only included six year of elementary (grammar) school. Now three years of pre school (kinder garden) and three years of middle school are being implemented. At present an optional course on astronomy if offered in high school (pre college). During my presentation I shall discuss problems concerning education in Mexico; mainly the lack of continuity in different levels of education, the lack of teacher training in science in general and the few topics of astronomy that are addressed. I shall mention for teacher training and public education, which includes books, lectures and videos.

  16. African Cultural Astronomy

    CERN Document Server

    Holbrook, Jarita C; Medupe, R. Thebe; Current Archaeoastronomy and Ethnoastronomy research in Africa

    2008-01-01

    Astronomy is the science of studying the sky using telescopes and light collectors such as photographic plates or CCD detectors. However, people have always studied the sky and continue to study the sky without the aid of instruments this is the realm of cultural astronomy. This is the first scholarly collection of articles focused on the cultural astronomy of Africans. It weaves together astronomy, anthropology, and Africa. The volume includes African myths and legends about the sky, alignments to celestial bodies found at archaeological sites and at places of worship, rock art with celestial imagery, and scientific thinking revealed in local astronomy traditions including ethnomathematics and the creation of calendars. Authors include astronomers Kim Malville, Johnson Urama, and Thebe Medupe; archaeologist Felix Chami, and geographer Michael Bonine, and many new authors. As an emerging subfield of cultural astronomy, African cultural astronomy researchers are focused on training students specifically for do...

  17. Optical timing receiver for the NASA laser ranging system. Part I. Constant-fraction discriminator

    International Nuclear Information System (INIS)

    Position-resolution capabilities of the NASA laser ranging system are essentially determined by time-resolution capabilities of its optical timing receiver. The optical timing receiver consists of a fast photoelectric device, primarily a standard of microchannel-plate-type photomultiplier or an avalanche photodiode detector, a timing discriminator, a high-precision time-interval digitizer, and a signal-processing system. The time-resolution capabilities of the receiver are determined by the photoelectron time spread of the photoelectric device, the time walk and resolution characteristics of the timing discriminator, and the time-interval digitizer. It is thus necessary to evaluate available fast photoelectronic devices with respect to their time-resolution capabilities, and to design a very low time walk timing discriminator and a high-precision time digitizer which will be used in the laser ranging system receiver. (auth)

  18. DSN radio science system description and requirements. [for satellite radio astronomy experiments

    Science.gov (United States)

    Mulhall, B. D. L.

    1977-01-01

    The data system created to collect the functions performed by the Deep Space Network in support of spacecraft radio science experiments is described. Some of the major functional requirements presently being considered for the system are delineated.

  19. Hybrid chaotic sequence for QS-CDMA system with RAKE receiver

    Institute of Scientific and Technical Information of China (English)

    饶妮妮; 许晓晶; 李少谦

    2004-01-01

    A class of the hybrid chaotic sequences is presented. The generator of the sequences is given and realized by the digital method. The hybrid chaotic sequences exhibit good random properties that are very important for the performance of QS-CDMA system with RAKE receiver. The performance of the system is analyzed when the hybrid chaotic sequences are used as spreading codes in a QS-CDMA system with RAKE receiver and compared with those obtained for m-sequences and logistic sequences. The results show that the hybrid chaotic sequences are a class of very promising spreading codes for QS-CDMA system.

  20. Application of Field System-FS9 and a PC to Antenna Control Unit interface in Radio Astronomy in Peru

    Science.gov (United States)

    Vidal, E. V. S.; Ishitsuka, J. I. I.; Koyama, K. Y.

    2006-08-01

    We are in the process to transform a 32m antenna in Peru, used for telecommunications, into a Radio Telescope to perform Radio Astronomy in Peru. The 32m antenna of Peru constructed by NEC was used for telecommunications with communications satellites at 6 GHz for transmission, and 4 GHz for reception. In collaboration of National Institute of Information and Communications Technology (NICT) Japan, and National Observatory of Japan we developed an Antenna Control System for the 32m antenna in Peru. It is based on the Field System FS9, software released by NASA for VLBI station, and an interface to link PC within FS9 software (PC-FS9) and Antenna Control Unit (ACU) of the 32 meters antenna. The PC-FS9 controls the antenna, commands are translated by interface into control signals compatibles with the ACU using: an I/O digital card with two 20bits ports to read azimuth and elevation angles, one 16bits port for reading status of ACU, one 24bits port to send pulses to start or stop operations of antenna, two channels are analogic outputs to drive the azimuth and elevation motors of the antenna, a LCD display to show the status of interface and error messages, and one serial port for communications with PC-FS9,. The first experiment of the control system was made with 11m parabolic antenna of Kashima Space Research Center (NICT), where we tested the right working of the routines implemented for de FS9 software, and simulations was made with looped data between output and input of the interface, both test were done successfully. With this scientific instrument we will be able to contribute with researching of astrophysics. We expect to into a near future to work at 6.7GHz to study Methanol masers, and higher frequencies with some improvements of the surface of the dish.

  1. Large area CCD image sensors for space astronomy

    Science.gov (United States)

    Schwarzschild, M.

    1979-01-01

    The Defense Advanced Research Projects Agency (DARPA) has a substantial program to develop a 2200 x 2200 pixel CCD (Charge Coupled Device) mosaic array made up of 400 individual CCD's, 110 x 110 pixels square. This type of image sensor appeared to have application in space and ground-based astronomy. Under this grant a CCD television camera system was built which was capable of operating an array of 4 CCD's to explore the suitability of the CCD's to explore the suitability of the CCD for astronomical applications. Two individual packaged CCD's were received and evaluated. Evaluation of the basic characteristics of the best individual chips was encouraging, but the manufacturer found that their yield in manufacturing this design is two low to supply sufficient CDD's for the DARPA mosaic array. The potential utility of large mosaic arrays in astronomy is still substantial and continued monitoring of the manufacturers progress in the coming year is recommended.

  2. Global Positioning System Time Transfer Receiver (GPS/TTR) prototype design and initial test evaluation

    Science.gov (United States)

    Oaks, J.; Frank, A.; Falvey, S.; Lister, M.; Buisson, J.; Wardrip, C.; Warren, H.

    1982-01-01

    Time transfer equipment and techniques used with the Navigation Technology Satellites were modified and extended for use with the Global Positioning System (GPS) satellites. A prototype receiver was built and field tested. The receiver uses the GPS L1 link at 1575 MHz with C/A code only to resolve a measured range to the satellite. A theoretical range is computed from the satellite ephemeris transmitted in the data message and the user's coordinates. Results of user offset from GPS time are obtained by differencing the measured and theoretical ranges and applying calibration corrections. Results of the first field test evaluation of the receiver are presented.

  3. Planetary radio astronomy from Voyager

    Science.gov (United States)

    Alexander, J. K.

    1983-01-01

    The technique of radio astronomy makes it possible for a remote observer to detect the presence of magnetic fields and plasmas in planetary environments. Prior to the flights of the Voyager spacecraft, radio astronomical studies of Jupiter from earth and from earth orbit had correctly predicted the strength and orientation of Jupiter's magnetic field and trapped radiation belts. The Voyager Planetary Radio Astronomy investigations have now provided measurements of the complete spectrum of low frequency radio emissions from both planets. Each Voyager instrument consists of a pair of orthogonal, 10-m, electric monopole antennas which are connected to a step-tuned, superheterodyne receiver operating over the frequency range from 1.2 kHz to 40.5 MHz. The Voyager trajectory provided observations from above both the sunlit and nightside hemispheres of Jupiter. Saturn's nonthermal radio emission has been observed at frequencies as low as 3 kHz and as high as 1.2 MHz.

  4. The Astro-Wise system: a federated information accumulator for astronomy

    NARCIS (Netherlands)

    Valentijn, Edwin A.; Verdoes Kleijn, Gijs

    2007-01-01

    The Astro-Wise consortium has designed a new paradigm, ‘Awe‘, and implemented a fully scalable and distributed information system to overcome the huge information avalanche in wide-field astronomical imaging Surveys.

  5. Challenges in Astronomy Education

    Science.gov (United States)

    De Greve, Jean-Pierre

    2010-11-01

    Astronomy is an attractive subject for education. It deals with fascination of the unknown and the unreachable, yet is uses tools, concepts and insights from various fundamental sciences such as mathematics, physics, chemistry, biology. Because of this it can be well used for introducing sciences to young people and to raise their interest in further studies in that direction. It is also an interesting subject for teaching as its different aspects (observation techniques, theory, data sampling and analysis, modelling,?) offer various didactical approaches towards different levels of pupils, students and different backgrounds. And it gives great opportunities to teach and demonstrate the essence of scientific research, through tutorials and projects. In this paper we discuss some of the challenges education in general, and astronomy in particular, faces in the coming decades, given the major geophysical and technological changes that can be deducted from our present knowledge. This defines a general, but very important background in terms of educational needs at various levels, and in geographical distribution of future efforts of the astronomical community. Special emphasis will be given to creative approaches to teaching, to strategies that are successful (such as the use of tutorials with element from computer games), and to initiatives complementary to the regular educational system. The programs developed by the IAU will be briefly highlighted.

  6. High-speed highly-flexible reconfigurable data acquisition system for astronomy

    Science.gov (United States)

    Pirger, Bruce E.; Schoenwald, Justin; Herter, Terry L.; Gull, George E.; Adams, Joseph D.; Keller, Luke D.; Berthoud, Marc; Henderson, Charles; Stacy, Gordon J.; Nikola, Thomas

    2006-06-01

    We have developed a high speed, flexible, data acquisition system and targeted it to astronomical imaging. The system is based on Field Programmable Gate Arrays (FPGAs) and provides a gigabit/sec fiber optic link between the electronics located on the instrument and the host computer. The FPGAs are reconfigurable over the fiber optic link for maximum flexibility. The system has initially been targeted at DRS Technologies' 256x256 Si:As and Si:Sb detectors used in FORCAST1, a mid-IR camera/spectrograph built by Cornell University for SOFIA. The initial configuration provides sixteen parallel channels of six Msamples/second 14-bit analog to digital converters. The system can coadd 256x256 images at over 1000 frames per second in up to 64 different memory positions. Array clocking and sampling is generated from uploaded clocking patterns in two independent memories. This configuration allows the user to quickly create, on the fly, any form of array clocking and sampling (destructive, non-destructive, sample up the ramp, additional reset frames, Fowler, single frames, co-added frames, multi-position chop, throw away frames, etc.) The electronics were designed in a modular fashion so that any number of analog channels from arrays or mosaics of arrays can be accommodated by using the appropriate number of FPGA boards and preamps. The preamp/analog to digital converter boards can be replaced as needed to operate any focal plane array or other sensor. The system also provides analog drive capability for controlling an X-Y chopping secondary mirror, nominal two position chopping, and can also synchronize to an externally driven chop source. Multiple array controllers can be synchronized together, allowing multi-channel systems to share a single chopping secondary, yet clock the focal planes differently from each other. Due to the flexibility of the FPGAs, it is possible to develop highly customized operating modes to maximize system performance or to enable novel

  7. Radio receivers

    Science.gov (United States)

    Bankov, V. N.; Barulin, L. G.; Zhodzishskii, M. I.; Malyshev, I. V.; Petrusinskii, V. V.

    The book is concerned with the design of microelectronic radio receivers and their components based on semiconductor and hybrid integrated circuits. Topics discussed include the hierarchical structure of radio receivers, the synthesis of structural schemes, the design of the principal functional units, and the design of radio receiver systems with digital signal processing. The discussion also covers the integrated circuits of multifunctional amplifiers, analog multipliers, charge-transfer devices, frequency filters, piezoelectronic devices, and microwave amplifiers, filters, and mixers.

  8. Solar receiver heliostat reflector having a linear drive and position information system

    Science.gov (United States)

    Horton, Richard H.

    1980-01-01

    A heliostat for a solar receiver system comprises an improved drive and control system for the heliostat reflector assembly. The heliostat reflector assembly is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth to track the sun and efficiently continuously reflect the sun's rays to a focal zone, i.e., heat receiver, which forms part of a solar energy utilization system, such as a solar energy fueled electrical power generation system. The improved drive system includes linear stepping motors which comprise low weight, low cost, electronic pulse driven components. One embodiment comprises linear stepping motors controlled by a programmed, electronic microprocessor. Another embodiment comprises a tape driven system controlled by a position control magnetic tape.

  9. Direct Heat-Flux Measurement System (MDF) for Solar central Receiver Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Ballestrin, J.

    2001-07-01

    A direct flux measurement system, MDF, has been designed, constructed and mounted on top of the SSPS-CRS tower at the Plataforma Solar de Almeria (PSA) in addition to an indirect flux measurement system based on a CCD camera. It's one of the main future objectives to compare systematically both measurements of the concentrated solar power, increasing in this way the confidence in the estimate of this quantity. Today everything is prepared to perform the direct flux measurement on the aperture of solar receivers: calorimeter array, data acquisition system and software. the geometry of the receiver determines the operation and analysis procedures to obtain the indecent power onto the defined area. The study of previous experiences with direct flux measurement systems ha been useful to define a new simpler and more accurate system. A description of each component of the MDF system is included, focusing on the heat-flux sensors or calorimeters, which enables these measurements to be done in a few seconds without water-cooling. The incident solar power and the spatial flux distribution on the aperture of the volumetric receiver Hitrec II are supplied by the above-mentioned MDF system. The first results obtained during the evaluation of this solar receiver are presented including a sunrise-sunset test. All these measurements have been concentrated in one coefficient that describes the global behavior of the Solar Power Plant. (Author) 18 refs.

  10. Direct Heat-Flux Measurement System (MDF) for Solar Central Receiver Evaluation

    International Nuclear Information System (INIS)

    A direct flux measurement system, MDF, has been designed, constructed and mounted on top of the SSPSCRS tower at the Plataforma Solar de Almeria (PSA) in addition to an indirect flux measurement system based on a CCD camera. It's one of the main future objectives to compare systematically both measurements of the concentrated solar power, increasing in this way the confidence in the estimate of this quantity. Today everything is prepared to perform the direct flux measurement on the aperture of solar receivers: calorimeter array, data acquisition system and software. The geometry of the receiver determines the operation and analysis procedures to obtain the incident power onto the defined area. The study of previous experiences with direct flux measurement systems has been useful to define a new, simpler and more accurate system. A description of each component of the MDF system is included, focusing on the heat-flux sensors or calorimeters, which enables these measurements to be done in a few seconds without water-cooling. The incident solar power and the spatial flux distribution on the aperture of the volumetric receiver Hitrec II are supplied by the above-mentioned MDF system. The first results obtained during the evaluation of this solar receiver are presented including a sunrise-sunset test. AU these measurements have been concentrated in one coefficient that describes the global behavior of the Solar Power Plant. (Author) 18 refs

  11. Efficient Compensation of Transmitter and Receiver IQ Imbalance in OFDM Systems

    Directory of Open Access Journals (Sweden)

    Tandur Deepaknath

    2010-01-01

    Full Text Available Radio frequency impairments such as in-phase/quadrature-phase (IQ imbalances can result in a severe performance degradation in direct-conversion architecture-based communication systems. In this paper, we consider the case of transmitter and receiver IQ imbalance together with frequency selective channel distortion. The proposed training-based schemes can decouple the compensation of transmitter and receiver IQ imbalance from the compensation of channel distortion in an orthogonal frequency division multiplexing (OFDM systems. The presence of frequency selective channel fading is a requirement for the estimation of IQ imbalance parameters when both transmitter/receiver IQ imbalance are present. However, the proposed schemes are equally applicable over a frequency flat/frequency selective channel when either transmitter or only receiver IQ imbalance is present. Once the transmitter and receiver IQ imbalance parameters are estimated, a standard channel equalizer can be applied to estimate/compensate for the channel distortion. The proposed schemes result in an overall lower training overhead and a lower computational requirement, compared to the joint compensation of transmitter/receiver IQ imbalance and channel distortion. Simulation results demonstrate that the proposed schemes provide a very efficient compensation with performance close to the ideal case without any IQ imbalance.

  12. Astronomy in Argentina

    CERN Document Server

    Muriel, Hernán

    2013-01-01

    This article analyses the current state of Astronomy in Argentina and describes its origins. We briefly describe the institutions where astronomical research takes place, the observational facilities available, the training of staff and professionals, and the role of the institutions in scientific promotion. We also discuss the outreach of Astronomy towards the general public, as well as amateur activities. The article ends with an analysis of the future prospects of astronomy in Argentina.

  13. Statistics in astronomy

    OpenAIRE

    Feigelson, Eric D.

    2009-01-01

    Perhaps more than other physical sciences, astronomy is frequently statistical in nature. The objects under study are inaccessible to direct manipulation in the laboratory, so the astronomer is restricted to observing a few external characteristics and inferring underlying properties and physics. Astronomy played a profound role in the historical development of statistics from the ancient Greeks through the 19th century. But the fields drifted apart in the 20th century as astronomy turned tow...

  14. Space and astronomy

    CERN Document Server

    Kirkland, Kyle

    2010-01-01

    Some daring explorers like to study distant frontiers by venturing out into them, but others prefer to study them by bringing them, or representative samples, a little closer to the lab. Both options are pursued in the fields of space and astronomy. Space exploration and astronomy are intricately linked and are examined in-depth in this guide. Dedicated to the scientists who explore the frontiers of space and astronomy-and the results of their unfamiliar findings-each chapter in Space and Astronomy explores one of the frontiers of this science. The development of technology, such as rocket pro

  15. Astronomy in Indian Schools

    Science.gov (United States)

    Bhatia, V. B.

    Tradition of astronomy in India goes back to ancient times. Many festivals and rituals are associated with astronomical phenomena. Indian children start learning rudiments of astronomy from primary classes. But primary teachers are not equipped to handle this subject so not much learning actually takes place. The first serious interface with astronomy occurs when children reach class X when they are 15 years old. Till last year astronomy was there in class XII also but it has now been dropped. This is a serious setback for the study of astronomy. In class X astronomy forms part of general science. Since children at this stage are not proficient in physics and mathematics the subject remains descriptive though there are useful activities for children to do. However the teachers are not equipped to handle this subject and there is no help in the form of visual material. So the subject remains neglected. The Indian astronomical community can help by training teachers and providing visual material. It must also urge authorities to reintroduce astronomy in class XII if astronomy is to flourish in India. Moreover India needs to network with developing countries share experiences with them and evolve a strategy that promotes astronomy.

  16. Design study of a low cost civil aviation GPS receiver system

    Science.gov (United States)

    Cnossen, R.; Gilbert, G. A.

    1979-01-01

    A low cost Navstar receiver system for civil aviation applications was defined. User objectives and constraints were established. Alternative navigation processing design trades were evaluated. Receiver hardware was synthesized by comparing technology projections with various candidate system designs. A control display unit design was recommended as the result of field test experience with Phase I GPS sets and a review of special human factors for general aviation users. Areas requiring technology development to ensure a low cost Navstar Set in the 1985 timeframe were identified.

  17. Adaptive Threshold Clipper Combining Receiver for Fast Frequency Hopping Systems during Partial-Band Noise Jamming

    Institute of Scientific and Technical Information of China (English)

    肖立民; 许希斌; 姚彦

    2001-01-01

    Diversity combining technologies are analyzed for fastfrequency-hopping spread spectrum systems during partial-band noise jamming to develop a novel combining receiver called an Adaptive Threshold Clipper Combining Receiver (ATCCR). The optimal clipping level for an ATCCR is analyzed, computed, and compared with several other diversity combining technologies. Since the ATCCR can estimate the power of the jamming and the number of jammed frequency cells to adaptively adjust the clipper's threshold, the system performance using the adaptive threshold clipper combining technique can be greatly improved.

  18. Alaska Athabascan stellar astronomy

    Science.gov (United States)

    Cannon, Christopher M.

    Stellar astronomy is a fundamental component of Alaska Athabascan cultures that facilitates time-reckoning, navigation, weather forecasting, and cosmology. Evidence from the linguistic record suggests that a group of stars corresponding to the Big Dipper is the only widely attested constellation across the Northern Athabascan languages. However, instruction from expert Athabascan consultants shows that the correlation of these names with the Big Dipper is only partial. In Alaska Gwich'in, Ahtna, and Upper Tanana languages the Big Dipper is identified as one part of a much larger circumpolar humanoid constellation that spans more than 133 degrees across the sky. The Big Dipper is identified as a tail, while the other remaining asterisms within the humanoid constellation are named using other body part terms. The concept of a whole-sky humanoid constellation provides a single unifying system for mapping the night sky, and the reliance on body-part metaphors renders the system highly mnemonic. By recognizing one part of the constellation the stargazer is immediately able to identify the remaining parts based on an existing mental map of the human body. The circumpolar position of a whole-sky constellation yields a highly functional system that facilitates both navigation and time-reckoning in the subarctic. Northern Athabascan astronomy is not only much richer than previously described; it also provides evidence for a completely novel and previously undocumented way of conceptualizing the sky---one that is unique to the subarctic and uniquely adapted to northern cultures. The concept of a large humanoid constellation may be widespread across the entire subarctic and have great antiquity. In addition, the use of cognate body part terms describing asterisms within humanoid constellations is similarly found in Navajo, suggesting a common ancestor from which Northern and Southern Athabascan stellar naming strategies derived.

  19. Visual lunar and planetary astronomy

    CERN Document Server

    Abel, Paul G

    2013-01-01

    With the advent of CCDs and webcams, the focus of amateur astronomy has to some extent shifted from science to art. The object of many amateur astronomers is now to produce “stunning images” that, although beautiful, are not intended to have scientific merit. Paul Abel has been addressing this issue by promoting visual astronomy wherever possible – at talks to astronomical societies, in articles for popular science magazines, and on BBC TV’s The Sky at Night.   Visual Lunar and Planetary Astronomy is a comprehensive modern treatment of visual lunar and planetary astronomy, showing that even in the age of space telescopes and interplanetary probes it is still possible to contribute scientifically with no more than a moderately priced commercially made astronomical telescope.   It is believed that imaging and photography is somehow more objective and more accurate than the eye, and this has led to a peculiar “crisis of faith” in the human visual system and its amazing processing power. But by anal...

  20. A linear receiver for visible light communication systems with phase modulated OFDM

    Science.gov (United States)

    Xie, Gui-Teng; Yu, Hong-Yi; Zhu, Yi-Jun; Ji, Xin-Sheng

    2016-07-01

    In the orthogonal frequency-division multiplexing (OFDM) systems for visible light communication (VLC), the peak-to-average power ratio (PAPR) of OFDM signals is the primary concern of high-speed data transmission. In order to get low PAPR signals and reduce the influence of nonlinearity of the light-emitting diode (LED), a phase modulated OFDM (PM-OFDM) system is developed and a linear receiver is presented. Unlike the conventional angle detection receiver implemented by arctangent calculator, the linear receiver has lower computation complexity and is immune to the threshold effect. Simulation results indicate that the proposed PM-OFDM obtains significant performance gains over DC-biased optical OFDM (DCO-OFDM) and precoded OFDM.

  1. Performance and Complexity Evaluation of Iterative Receiver for Coded MIMO-OFDM Systems

    Directory of Open Access Journals (Sweden)

    Rida El Chall

    2016-01-01

    Full Text Available Multiple-input multiple-output (MIMO technology in combination with channel coding technique is a promising solution for reliable high data rate transmission in future wireless communication systems. However, these technologies pose significant challenges for the design of an iterative receiver. In this paper, an efficient receiver combining soft-input soft-output (SISO detection based on low-complexity K-Best (LC-K-Best decoder with various forward error correction codes, namely, LTE turbo decoder and LDPC decoder, is investigated. We first investigate the convergence behaviors of the iterative MIMO receivers to determine the required inner and outer iterations. Consequently, the performance of LC-K-Best based receiver is evaluated in various LTE channel environments and compared with other MIMO detection schemes. Moreover, the computational complexity of the iterative receiver with different channel coding techniques is evaluated and compared with different modulation orders and coding rates. Simulation results show that LC-K-Best based receiver achieves satisfactory performance-complexity trade-offs.

  2. Combined cycle solar central receiver hybrid power system study. Final technical report. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-11-01

    This study develops the conceptual design for a commercial-scale (nominal 100 MWe) central receiver solar/fossil fuel hybrid power system with combined cycle energy conversion. A near-term, metallic heat pipe receiver and an advanced ceramic tube receiver hybrid system are defined through parametric and market potential analyses. Comparative evaluations of the cost of power generation, the fuel displacement potential, and the technological readiness of these two systems indicate that the near-term hybrid system has better potential for commercialization by 1990. Based on the assessment of the conceptual design, major cost and performance improvements are projected for the near-term system. Constraints preventing wide-spread use were not identified. Energy storage is not required for this system and analyses show no economic advantages with energy storage provisions. It is concluded that the solar hybrid system is a cost effective alternative to conventional gas turbines and combined cycle generating plants, and has potential for intermediate-load market penetration at 15% annual fuel escalation rate. Due to their flexibility, simple solar/nonsolar interfacing, and short startup cycles, these hybrid plants have significant operating advantages. Utility company comments suggest that hybrid power systems will precede stand-alone solar plants.

  3. WorldWide Telescope: A Newly Open Source Astronomy Visualization System

    Science.gov (United States)

    Fay, Jonathan; Roberts, Douglas A.

    2016-01-01

    After eight years of development by Microsoft Research, WorldWide Telescope (WWT) was made an open source project at the end of June 2015. WWT was motivated by the desire to put new surveys of objects, such as the Sloan Digital Sky Survey in the context of the night sky. The development of WWT under Microsoft started with the creation of a Windows desktop client that is widely used in various education, outreach and research projects. Using this, users can explore the data built into WWT as well as data that is loaded in. Beyond exploration, WWT can be used to create tours that present various datasets a narrative format.In the past two years, the team developed a collection of web controls, including an HTML5 web client, which contains much of the functionality of the Windows desktop client. The project under Microsoft has deep connections with several user communities such as education through the WWT Ambassadors program, http://wwtambassadors.org/ and with planetariums and museums such as the Adler Planetarium. WWT can also support research, including using WWT to visualize the Bones of the Milky Way and rich connections between WWT and the Astrophysical Data Systems (ADS, http://labs.adsabs.harvard.edu/adsabs/). One important new research connection is the use of WWT to create dynamic and potentially interactive supplements to journal articles, which have been created in 2015.Now WWT is an open source community lead project. The source code is available in GitHub (https://github.com/WorldWideTelescope). There is significant developer documentation on the website (http://worldwidetelescope.org/Developers/) and an extensive developer workshops (http://wwtworkshops.org/?tribe_events=wwt-developer-workshop) has taken place in the fall of 2015.Now that WWT is open source anyone who has the interest in the project can be a contributor. As important as helping out with coding, the project needs people interested in documentation, testing, training and other roles.

  4. Advances in astronomy and astrophysics 9

    CERN Document Server

    Kopal, Zdenek

    1972-01-01

    Advances in Astronomy and Astrophysics, Volume 9 covers reviews on the advances in astronomy and astrophysics. The book presents reviews on the Roche model and its applications to close binary systems. The text then describes the part played by lunar eclipses in the evolution of astronomy; the classical theory of lunar eclipses; deviations from geometrical theory; and the methods of photometric observations of eclipses. The problems of other phenomena related in one way or another to lunar eclipses are also considered. The book further tackles the infrared observation on the eclipsed moon, as

  5. Astronomy for beginners

    CERN Document Server

    Becan, Jeff

    2008-01-01

    Astronomy For Beginners is a friendly and accessible guide to our universe, our galaxy, our solar system and the planet we call home. Each year as we cruise through space on this tiny blue-green wonder, a number of amazing and remarkable events occur. For example, like clockwork, we'll run head-on into asteroid and cometary debris that spreads shooting stars across our skies. On occasion, we'll get to watch the disk of the Moon passing the Sun, casting its shadow on the face of the Earth, and sometimes we'll get to watch our own shadow as it glides across the face of the Moon. The Sun's path w

  6. Interdisciplinary Astronomy Activities

    Science.gov (United States)

    Nerantzis, Nikolaos; Mitrouda, Aikaterini; Reizopoulou, Ioanna; Sidiropoulou, Eirini; Hatzidimitriou, Antonios

    2016-04-01

    On November 9th, 2015, three didactical hours were dedicated to Interdisciplinary Astronomy Activities (http://wp.me/p6Hte2-1I). Our students and their teachers formed three groups and in rotation, were engaged with the following activities: (a) viewing unique images of the Cosmos in the mobile planetarium STARLAB (http://www.planitario.gr/tholos-starlab-classic-standard.html), (b) watching the following videos: Journey to the end of the universe (https://youtu.be/Ufl_Nwbl8xs), Rosetta update (https://youtu.be/nQ9ivd7wv30), The Solar System (https://youtu.be/d66dsagrTa0), Ambition the film (https://youtu.be/H08tGjXNHO4) in the school's library. Students and teachers were informed about our solar system, the Rosetta mission, the universe, etc. and (c) tactile activities such as Meet our home and Meet our neighbors (http://astroedu.iau.org, http://nuclio.org/astroneighbours/resources) and the creation of planets' 3D models (Geology-Geography A' Class Student's book, pg.15). With the activities above we had the pleasure to join the Cosmic Light Edu Kit / International Year of Light 2015 program. After our Interdisciplinary Astronomy Activities, we did a "small" research: our students had to fill an evaluation about their educational gains and the results can be found here http://wp.me/p6Hte2-2q. Moreover, we discussed about Big Ideas of Science (http://wp.me/p3oRiZ-dm) and through the "big" impact of the Rosetta mission & the infinity of our universe, we print posters with relevant topics and place them to the classrooms. We thank Rosa Doran (Nuclio - President of the Executive Council) for her continuous assistance and support on innovative science teaching proposals. She is an inspiration.

  7. Extragalactic infrared astronomy

    International Nuclear Information System (INIS)

    The paper concerns the field of Extragalactic Infrared Astronomy, discussed at the Fourth RAL Workshop on Astronomy and Astrophysics. Fifteen papers were presented on infrared emission from extragalactic objects. Both ground-(and aircraft-) based and IRAS infrared data were reviewed. The topics covered star formation in galaxies, active galactic nuclei and cosmology. (U.K.)

  8. Indian Astronomy: History of

    Science.gov (United States)

    Mercier, R.; Murdin, P.

    2002-01-01

    From the time of A macronryabhat under dota (ca AD 500) there appeared in India a series of Sanskrit treatises on astronomy. Written always in verse, and normally accompanied by prose commentaries, these served to create an Indian tradition of mathematical astronomy which continued into the 18th century. There are as well texts from earlier centuries, grouped under the name Jyotishaveda macronn d...

  9. Detailed Mathematical Analysis and Performance Evaluation of MIMO-OFDM-CDMA System Using ZF Receiver

    Directory of Open Access Journals (Sweden)

    Ekta Charaya

    2013-07-01

    Full Text Available In this paper, we have presented the detailed mathematical analysis of the output signal to interference noise ratio (SINR for MIMO-OFDM-CDMA system using joint space-time frequency (STF spreading with ZF receiver. A 2x2 and 4x4 MIMO system is used for performance evaluation in terms of BER. The analysis shows that output SINR decreases, as the number of users increases. The average bit error probability of the system using ZF receiver is derived for different number of users. We also present exponential bound of the complementary error function (erfc for probability of error. Simulation results of MIMO-OFDM-CDMA system are in line with the results obtained through mathematical analysis

  10. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  11. Waste Receiving and Processing Facility Module 1 Data Management System software requirements specification

    Energy Technology Data Exchange (ETDEWEB)

    Rosnick, C.K.

    1996-04-19

    This document provides the software requirements for Waste Receiving and Processing (WRAP) Module 1 Data Management System (DMS). The DMS is one of the plant computer systems for the new WRAP 1 facility (Project W-0126). The DMS will collect, store and report data required to certify the low level waste (LLW) and transuranic (TRU) waste items processed at WRAP 1 as acceptable for shipment, storage, or disposal.

  12. Waste Receiving and Processing Facility Module 1 Data Management System Software Requirements Specification

    International Nuclear Information System (INIS)

    This document provides the software requirements for Waste Receiving and Processing (WRAP) Module 1 Data Management System (DMS). The DMS is one of the plant computer systems for the new WRAP 1 facility (Project W-026). The DMS will collect, store and report data required to certify the low level waste (LLW) and transuranic (TRU) waste items processed at WRAP 1 as acceptable for shipment, storage, or disposal

  13. Waste receiving and processing facility module 1 data management system software project management plan

    International Nuclear Information System (INIS)

    This document provides the software development plan for the Waste Receiving and Processing (WRAP) Module 1 Data Management System (DMS). The DMS is one of the plant computer systems for the new WRAP 1 facility (Project W-026). The DMS will collect, store, and report data required to certify the low level waste (LLW) and transuranic (TRU) waste items processed at WRAP 1 as acceptable for shipment, storage, or disposal

  14. Waste Receiving and Processing Facility Module 1 Data Management System software requirements specification

    International Nuclear Information System (INIS)

    This document provides the software requirements for Waste Receiving and Processing (WRAP) Module 1 Data Management System (DMS). The DMS is one of the plant computer systems for the new WRAP 1 facility (Project W-0126). The DMS will collect, store and report data required to certify the low level waste (LLW) and transuranic (TRU) waste items processed at WRAP 1 as acceptable for shipment, storage, or disposal

  15. Waste Receiving and Processing Facility Module 1 Data Management System Software Requirements Specification

    Energy Technology Data Exchange (ETDEWEB)

    Brann, E.C. II

    1994-09-09

    This document provides the software requirements for Waste Receiving and Processing (WRAP) Module 1 Data Management System (DMS). The DMS is one of the plant computer systems for the new WRAP 1 facility (Project W-026). The DMS will collect, store and report data required to certify the low level waste (LLW) and transuranic (TRU) waste items processed at WRAP 1 as acceptable for shipment, storage, or disposal.

  16. History of Oriental Astronomy

    Science.gov (United States)

    Ansari, S. M. Razaullah

    2002-12-01

    This volume deals specifically with recent original research in the history of Chinese, Korean, Japanese, Islamic, and Indian astronomy. It strikes a balance between landmarks of history of Ancient and Medieval Astronomy in the Orient on one hand, and on the other the transmission of the European Astronomy into the countries of the Orient. Most contributions are based on research by the experts in this field. The book also indicates the status of astronomy research in non-European cultural areas of the world. The book is especially of interest to historians of astronomy and science, and students of cultural heritage. Link: http://www.wkap.nl/prod/b/1-4020-0657-8

  17. Joseph Henry and Astronomy

    Science.gov (United States)

    Rothenberg, Marc

    2016-01-01

    Joseph Henry (1797-1878) is best known for his work in electromagnetism and as the first secretary of the Smithsonian Institution. But he was also a pioneer solar physicist, an early advocate of US participation in astrophysics, and a facilitator of international cooperation in astronomy. This paper will briefly trace his role in the development of the US astronomical community from the time he taught astronomy at Princeton in the 1830s through his death, focusing on failed efforts to persuade US astronomers and patrons of astronomy that the best path for US astronomy should be astrophysics. He thought that the US could make a more significant contribution to astronomy science by striking out on a less travelled path rather than competing with the established European observatories.

  18. Peer Instruction for Astronomy

    Science.gov (United States)

    Green, Paul

    Peer Instruction for Astronomy is an instructor's guide to an exciting and easily-implemented enhancement for lecture classes in introductory astronomy. Application of this powerful and efficient teaching technique requires that the instructor have on hand a large number of thought-provoking, conceptual short answer questions aimed at a variety of levels. While significant numbers of such questions have been published for use in Physics, Peer Instruction for Astronomy provides the first such compilation for Astronomy, and includes hints on use of the technique and applications of the method. KEY TOPICS: Covers peer instruction, incentives, a large database of conceptual questions for use in class, and a list of readings and resources. MARKET: Ideal for introductory astronomy instructors at the undergraduate or advanced high school level.

  19. Highlights of Astronomy, Vol. 16

    Science.gov (United States)

    Montmerle, Thierry

    2015-04-01

    Part I. Invited Discourses: 1. The Herschel view of star formation; 2. Past, present and future of Chinese astronomy; 3. The zoo of galaxies; 4. Supernovae, the accelerating cosmos, and dark energy; Part II. Joint Discussion: 5. Very massive stars in the local universe; 6. 3-D views of the cycling Sun in stellar context; 7. Ultraviolet emission in early-type galaxies; 8. From meteors and meteorites to their parent bodies: current status and future developments; 9. The connection between radio properties and high-energy emission in AGNs; 10. Space-time reference systems for future research; Part III. Special Sessions: 11. Origin and complexity of massive star clusters; 12. Cosmic evolution of groups and clusters of galaxies; 13. Galaxy evolution through secular processes; 14. New era for studying interstellar and intergalactic magnetic fields; 15. The IR view of massive stars: the main sequence and beyond; 16. Science with large solar telescopes; 17. The impact hazard: current activities and future plans; 18. Calibration of star-formation rate measurements across the electromagnetic spectrum; 19. Future large scale facilities; 20. Dynamics of the star-planet relations strategic plan and the Global Office of Astronomy for Development; 21. Strategic plan and the Global Office of Astronomy for Development; 22. Modern views of the interstellar medium; 23. High-precision tests of stellar physics from high-precision photometry; 24. Communicating astronomy with the public for scientists; 25. Data intensive astronomy; 26. Unexplained spectral phenomena in the interstellar medium; 27. Light pollution: protecting astronomical sites and increasing global awareness through education.

  20. Real-Time GPS Receiver System Implementation for Providing Location Based Services and SMS Tracking

    Directory of Open Access Journals (Sweden)

    Pratik K. Gaikwad

    2014-05-01

    Full Text Available This paper describes the design of a real-time GPS receiver system in a very simple and efficient fashion for navigation, tracking and positioning. This system is designed to provide location based parameters in real time like latitude, longitude, altitude, current location name and altitude. The values of these parameters are displayed on a GUI (Graphical User Interface. The system also provides a website application where the values of the parameters on the GUI are displayed in a tabulated form on the website. The parameter values are continuously updated and are displayed on the GUI. The updated parameter values on the GUI are also added to the table in the website. Hence the table shows the real-time parameter values along with the values which were previously displayed on the GUI. An internet based SMS (Short Message Service application is also developed which will message the real time latitude, longitude, altitude, speed and location name to the user’s mobile. The system consists of an antenna which acquires the satellite signals. These signals are given to the GPS receiver. The receiver is provided with a Universal Serial Bus (USB connector so that it compatible and can be easily connected to a Personal Computer (PC or laptop. The system software in the PC or laptop is developed in Visual Basic.NET computer programming language. The system is easy to use and provides real-time results in the form of visual displays.

  1. Blind receiver for OFDM systems via sequential Monte Carlo in factor graphs

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; ZHANG Hai-bin; XU You-yun; LIU Xin-zhao

    2007-01-01

    Estimation and detection algorithms for orthogonal frequency division multiplexing (OFDM) systems can be developed based on the sum-product algorithms, which operate by message passing in factor graphs. In this paper, we apply the sampling method (Monte Carlo) to factor graphs, and then the integrals in the sum-product algorithm can be approximated by sums, which results in complexity reduction. The blind receiver for OFDM systems can be derived via Sequential Monte Carlo(SMC) in factor graphs, the previous SMC blind receiver can be regarded as the special case of the sum-product algorithms using sampling methods. The previous SMC blind receiver for OFDM systems needs generating samples of the channel vector assuming the channel has an a priori Gaussian distribution. In the newly-built blind receiver, we generate samples of the virtual-pilots instead of the channel vector, with channel vector which can be easily computed based on virtual-pilots. As the size of the virtual-pilots space is much smaller than the channel vector space, only small number of samples are necessary, with the blind detection being much simpler. Furthermore, only one pilot tone is needed to resolve phase ambiguity and differential encoding is not used anymore. Finally, the results of computer simulations demonstrate that the proposal can perform well while providing significant complexity reduction.

  2. Development of ground-based ELF/VLF receiver system in Wuhan and its first results

    Science.gov (United States)

    Chen, Yanping; Yang, Guobin; Ni, Binbin; Zhao, Zhengyu; Gu, Xudong; Zhou, Chen; Wang, Feng

    2016-05-01

    A new digital low-frequency receiver system has been developed at Wuhan University for sensitive reception of low-latitude broadband Extremely Low Frequency (ELF) and Very Low Frequency (VLF) radio waves originating from either natural or artificial sources. These low-frequency radio waves are useful for ionospheric remote sensing, geospace environment monitoring, and submarine communications. This paper presents the principle and architecture of the system framework, including magnetic loop antenna design, low-noise analog front-end and digital receiver with data sampling and transmission. A new structure is adopted in the analog front end to provide high common-mode rejection and to reduce interference. On basis of field programmable gate array (FPGA) device and Universal Serial Bus (USB) architecture, the digital receiver is developed along with time keeping and synchronization module. The validity and feasibility of the self-developed ground-based ELF/VLF receiver system is evaluated by first results of experimental data that show the temporal variation of broadband ELF/VLF wave spectral intensity in Wuhan (30.54 °N, 114.37 °E). In addition to the acquisition of VLF transmitter signals at various frequencies, tweek atmospherics are also clearly captured to occur at multiple modes up to n = 6.

  3. SAGE based iterative receiver for joint synchronization and channel estimation in uplink MIMO-OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    JIANG Zheng; QIN Xiao-fang; ZHANG Xin; CHANG Yong-yu

    2008-01-01

    A new Turbo iterative receiver structure is proposed for the uplink multiple-input multiple-output orthogonal frequency division multiple access (MIMO-OFDMA) systems. The space-alternating generalized expectation-maximization (SAGE) algorithm is naturally embedded in the framework of iterative receiver to perform synchronization and detection using the Turbo detector outputs. In each iteration, the expectation step intends to remove the multiple access interference (MAI) caused by other asynchronous users, and the maximization step is utilized to estimate the required parameters (i.e., timing offset, carrier frequency offset, channel state information, etc.) sequentially for each user. Simulation results show that the proposed algorithm can approach the performance of ideal receiver closely, while the processing complexity is rather lower than the conventional detectors.

  4. Solar power tower design guide: Solar thermal central receiver power systems. A source of electricity and/or process heat

    Science.gov (United States)

    Battleson, K. W.

    1981-04-01

    Preliminary evaluations of whether a solar thermal central receiver plant is technically and economically feasible and desirable, for the potential user's application are reported. The cost elements, performance, and operation of solar central receiver systems are described.

  5. Improved Iterative Parallel Interference Cancellation Receiver for Future Wireless DS-CDMA Systems

    Science.gov (United States)

    Morosi, Simone; Fantacci, Romano; Bernacchioni, Andrea

    2005-12-01

    We present a new turbo multiuser detector for turbo-coded direct sequence code division multiple access (DS-CDMA) systems. The proposed detector is based on the utilization of a parallel interference cancellation (PIC) and a bank of turbo decoders. The PIC is broken up in order to perform interference cancellation after each constituent decoder of the turbo decoding scheme. Moreover, in the paper we propose a new enhanced algorithm that provides a more accurate estimation of the signal-to-noise-plus-interference-ratio used in the tentative decision device and in the MAP decoding algorithm. The performance of the proposed receiver is evaluated by means of computer simulations for medium to very high system loads, in AWGN and multipath fading channel, and compared to recently proposed interference cancellation-based iterative MUD, by taking into account the number of iterations and the complexity involved. We will see that the proposed receiver outperforms the others especially for highly loaded systems.

  6. A Pedestrian Dead Reckoning System Integrating Low-Cost MEMS Inertial Sensors and GPS Receiver

    Directory of Open Access Journals (Sweden)

    Jin-feng Li

    2014-04-01

    Full Text Available The body-mounted inertial systems for pedestrian navigation do not require any preinstalled facilities and can run autonomously. The advantages over other technologies make it especially attractive for the applications such as first responders, military and consumer markets. The hardware platform integrating the low-cost, low-power and small-size MEMS (micro-electro-mechanical systems inertial sensors and GPS (global positioning system receiver is proposed. When the satellite signals are available, the location of the pedestrian is directly obtained from the GPS receiver. The inertial sensors are the complement of the GPS receiver in places where the GPS signals are not available, such as indoors, urban canyons and places under dense foliages. The height tracking is achieved by the barometer. The proposed PDR (pedestrian dead reckoning algorithm is real-timely implemented in the platform. The simple but effective step detection and step length estimation method are realized to reduce the computation and memory requirements on the microprocessor. A complementary filter is proposed to fuse the data from the accelerometer, gyroscope and digital compass for decreasing the heading error, which is the main error source in positioning. The reliability and accuracy of the proposed system is verified by field pedestrian walking tests in outdoors and indoors. The positioning error is less than 4% of the total traveled distance. The results indicate that the pedestrian dead reckoning system is able to provide satisfactory tracking performance.

  7. Performance Analysis of Ultra Wideband Receivers for High Data Rate Wireless Personal Area Network System

    Directory of Open Access Journals (Sweden)

    Bikramaditya Das

    2010-03-01

    Full Text Available For high data rate ultra wideband communication system, performance comparison of Rake, MMSE andRake-MMSE receivers is attempted in this paper. Further a detail study on Rake-MMSE time domainequalizers is carried out taking into account all the important parameters such as the effect of the numberof Rake fingers and equalizer taps on the error rate performance. This receiver combats inter-symbolinterference by taking advantages of both the Rake and equalizer structure. The bit error rateperformances are investigated using MATLAB simulation on IEEE 802.15.3a defined UWB channelmodels. Simulation results show that the bit error rate probability of Rake-MMSE receiver is much betterthan Rake receiver and MMSE equalizer. Study on non-line of sight indoor channel models illustratesthat bit error rate performance of Rake-MMSE (both LE and DFE improves for CM3 model with smallerspread compared to CM4 channel model. It is indicated that for a MMSE equalizer operating at low tomedium SNR values, the number of Rake fingers is the dominant factor to improve system performance,while at high SNR values the number of equalizer taps plays a more significant role in reducing the errorrate.

  8. Metal Mesh Filters for Terahertz Receivers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical objective of this SBIR program is to develop and demonstrate metal mesh filters for use in NASA's low noise receivers for terahertz astronomy and...

  9. Receiver design of UWB radio systems for an impulsive noise environment

    Institute of Scientific and Technical Information of China (English)

    贾琳; 张中兆

    2004-01-01

    The performance of UWB (uhrawide bandwidth) radio systems under an impulsive noise environment is first investigated. In the analysis, the Middleton's class A model is used as a model of the impulsive noise. At first, the statistical characteristics of the in-phase and quadrature components of the impulsive noise are investigated, and it is proved that unlike Gaussian noise, these components are dependent especially on the impulsive noise with small impulsive indices. The probability that the high amplitude noise is emitted in the in-phase component which becomes firstly larger and then smaller for the larger quadrature component of impulsive noise is presented. Next, the performance of conventional UWB radio systems designed for the Gaussian noise under the impulsive noise is evaluated and numerical results show that the performance of the conventional UWB radio systems is much degraded by the effect of the impulsive noise.Using the dependence between the in-phase and quadrature components of the impulsive noise, a novel UWB receiver designed for impulsive noise is proposed and the performance improvement achieved by the receiver is evaluated. Numerical results show that the performance of UWB radio systems is much improved by employing the proposed receiver.

  10. Teaching Astronomy with Technology

    Science.gov (United States)

    Austin, Carmen; Impey, Chris David; Wenger, Matthew

    2015-01-01

    Students today are expected to have access to computers and the Internet. Students young and old, in school and out of school, are interested in learning about astronomy, and have computers to use for this. Teach Astronomy is a website with a comprehensive digital astronomy textbook freely available to students and educators. In addition to the textbook, there are astronomy Wikipedia articles, image archives from Astronomy Picture of the Day and AstroPix, and video lectures covering all topics of astronomy. Teach Astronomy has a unique search tool called the wikimap that can be used to search through all of the resources on the site. Astronomy: State of the Art (ASOTA) is a massive, open, online course (MOOC). Over 18,000 students have enrolled over the past year and half. This MOOC has been presented in various forms. First, only to students on the web, with content released weekly on host site Udemy. Then to university students who met formally in the classroom for educational activities, but were also expected to watch lectures online on their own time. Presently, it is available online for students to go at their own pace. In the future it will be available in an extended format on a new host site, Coursera. ASOTA instructors use social media to interact with students. Students ask questions via the course host site, Udemy. Live question and answer sessions are conducted using Google Hangouts on Air, and interesting and relevant astronomy news, or supplementary educational content is shared via the ASOTA Facebook page. Teaching on the Internet may seem impersonal and impractical, but by learning to use all of these tools, instructors have the ability to interact with students, and keep them engaged.

  11. Making Space for Specialized Astronomy Resources

    Science.gov (United States)

    MacMillan, D.

    2007-10-01

    With the growth of both free and subscription-based resources, articles on astronomy have never been easier to find. Locating the best and most current materials for any given search, however, now requires multiple tools and strategies dependent on the query. An analysis of the tools currently available shows that while astronomy is well-served by Google Scholar, Scopus and Inspec, its literature is best accessed through specialized resources such as ADS (Astrophysics Data System). While no surprise to astronomers, this has major implications for those of us who teach information literacy skills to astronomy students and work in academic settings where astronomy is just one of many subjects for which our non-specialist colleagues at the reference desk provide assistance. This paper will examine some of the implications of this analysis for library instruction, reference assistance and training, and library webpage development.

  12. Ideas for Citizen Science in Astronomy

    CERN Document Server

    Marshall, Philip J; Fletcher, Leigh N

    2014-01-01

    We review the relatively new, internet-enabled, and rapidly-evolving field of citizen science, focusing on research projects in stellar, extragalactic and solar system astronomy that have benefited from the participation of members of the public, often in large numbers. We find these volunteers making contributions to astronomy in a variety of ways: making and analyzing new observations, visually classifying features in images and light curves, exploring models constrained by astronomical datasets, and initiating new scientific enquiries. The most productive citizen astronomy projects involve close collaboration between the professionals and amateurs involved, and occupy scientific niches not easily filled by great observatories or machine learning methods: citizen astronomers are most strongly motivated by being of service to science. In the coming years we expect participation and productivity in citizen astronomy to increase, as survey datasets get larger and citizen science platforms become more efficient...

  13. Community Based Astronomy: Bringing families and communities together

    Science.gov (United States)

    Mayo, L. A.

    2001-12-01

    Astronomy in K-12 formal education is still largely underrepresented as a science. Yet, it is arguably one of the most engaging and entertaining of the physical sciences. Many school systems have been slow to adopt curriculum frameworks that include astronomy. Even when astronomy is required either as a distinct subject or hidden within the catagory of "Earth science", many teachers spend little time on it in their classrooms since they have no formal training in this subject. A community based, informal astronomy education model that encorporates resources from government agencies, industry, local colleges, science centers and planetariums, families, civic groups, schools, and amateur astronomy clubs can provide a solution and be highly effective in creating sustained learning environments in this discipline as well as fostering an atmosphere of general acceptance and promotion of astronomy by whole communities. In addition, the opportunity exists to reinforce the teaching of astronomy in schools through the involvement of these groups in an informal education setting. This paper will discuss a Community Based Astronomy program that has been implemented in Montgomery County, Maryland. The tie-in to formal education through both schools and systemic reform initiatives will be presented. In addition, detailed guidelines for running astronomy clubs in conjunction with family astronomy nights will be provided.

  14. Design of transmitter and receiver for experimental blue-green laser communication system

    Science.gov (United States)

    Xu, Tao; Chen, Xiaolu; Wen, Dong; Sun, Xiaolei

    2015-02-01

    An experimental blue-green laser communication system was developed using optical pulse position modulation (PPM) to study the feasibility of high-rate underwater communication among submerged objects. As a primary optical modulation means, PPM modulation is reviewed firstly. By comparison with other means, the conclusion was drawn that PPM has lower power requirement and it is a near optimal modulation for background-limited optical communications. For establishing laser beam propagating through the channel with modulated information through different pulse positions from the transmitter to the receiver, the transmitter subsystem and the receiver subsystem are developed and the key techniques are described separately in detail. Results indicated that the whole blue-green communication system was compact, efficient, reliable and inexpensive, and achieved a high-speed rate communication up to megabits per second and a reasonably low error rates.

  15. Forecast-Driven Enhancement of Received Signal Strength (RSS-Based Localization Systems

    Directory of Open Access Journals (Sweden)

    Claudio Gallicchio

    2013-10-01

    Full Text Available Real-time user localization in indoor environments is an important issue in ambient assisted living (AAL. In this context, localization based on received signal strength (RSS has received considerable interest in the recent literature, due to its low cost and energy consumption and to its availability on all wireless communication hardware. On the other hand, the RSS-based localization is characterized by a greater error with respect to other technologies. Restricting the problem to localization of AAL users in indoor environments, we demonstrate that forecasting with a little user movement advance (for example, when the user is about to leave a room provides significant benefits to the accuracy of RSS-based localization systems. Specifically, we exploit echo state networks (ESNs fed with RSS measurements and trained to recognize patterns of user’s movements to feed back to the RSS-based localization system.

  16. FPGA-Based Communications Receivers for Smart Antenna Array Embedded Systems

    Directory of Open Access Journals (Sweden)

    James Millar

    2006-10-01

    Full Text Available Field-programmable gate arrays (FPGAs are drawing ever increasing interest from designers of embedded wireless communications systems. They outpace digital signal processors (DSPs, through hardware execution of a wide range of parallelizable communications transceiver algorithms, at a fraction of the design and implementation effort and cost required for application-specific integrated circuits (ASICs. In our study, we employ an Altera Stratix FPGA development board, along with the DSP Builder software tool which acts as a high-level interface to the powerful Quartus II environment. We compare single- and multibranch FPGA-based receiver designs in terms of error rate performance and power consumption. We exploit FPGA operational flexibility and algorithm parallelism to design eigenmode-monitoring receivers that can adapt to variations in wireless channel statistics, for high-performing, inexpensive, smart antenna array embedded systems.

  17. FPGA-Based Communications Receivers for Smart Antenna Array Embedded Systems

    Directory of Open Access Journals (Sweden)

    Millar James

    2006-01-01

    Full Text Available Field-programmable gate arrays (FPGAs are drawing ever increasing interest from designers of embedded wireless communications systems. They outpace digital signal processors (DSPs, through hardware execution of a wide range of parallelizable communications transceiver algorithms, at a fraction of the design and implementation effort and cost required for application-specific integrated circuits (ASICs. In our study, we employ an Altera Stratix FPGA development board, along with the DSP Builder software tool which acts as a high-level interface to the powerful Quartus II environment. We compare single- and multibranch FPGA-based receiver designs in terms of error rate performance and power consumption. We exploit FPGA operational flexibility and algorithm parallelism to design eigenmode-monitoring receivers that can adapt to variations in wireless channel statistics, for high-performing, inexpensive, smart antenna array embedded systems.

  18. Problems synthesis device clock synchronization receivers satellite telecommunication data transmission systems

    Directory of Open Access Journals (Sweden)

    J. M. Boiko

    2014-09-01

    Full Text Available The paper presents mathematical models to formalize an analytical description of receivers clocked devices of satellite telecommunication transmit systems. The principles of synchronization synthesis in view of the negative factors by minimizing their influence on signal processing are shown. A broadening theoretical interpretation of the analytical description for the operation and optimization of receiver parameters in a real and complex interference effects on signal processing system manipulated by examining changes in the density distribution of errors regarding synchronization of clock synchronization. It is proposed to optimize clocked devices by providing them like standalone device and evaluate the quality of the accuracy degree of the fluctuation variance errors. It is shown that the use of this approach allows for structural synthesis device clock to search device structure that pro vides the maximum value assigned to the criterion of efficiency.

  19. Astronomy and culture

    CERN Document Server

    Hetherington, Edith

    2009-01-01

    While astronomy is a burgeoning science, with tremendous increases in knowledge every year, it also has a tremendous past, one that has altered humanity's understanding of our place in the universe. The impact of astronomy on culture - whether through myths and stories, or through challenges to the intellectual status quo - is incalculable. This volume in the Greenwood Guides to the Universe series examines how human cultures, in all regions and time periods, have tried to make sense of the wonders of the universe. Astronomy and Culture shows students how people throughout time have struggled

  20. Discovering Astronomy Through Poetry

    Science.gov (United States)

    Mannone, John C.

    2011-05-01

    The literature is replete with astronomical references. And much of that literature is poetry. Using this fact, not only can the teacher infuse a new appreciation of astronomy, but also, the student has the opportunity to rediscover history through astronomy. Poetry can be an effective icebreaker in the introduction of new topics in physics and astronomy, as well as a point of conclusion to a lecture. This presentation will give examples of these things from the ancient literature (sacred Hebraic texts), classical literature (Homer's Iliad and Odyssey), traditional poetry (Longfellow, Tennyson and Poe) and modern literature (Frost, Kooser, and others, including the contemporary work of this author).

  1. General formula for the incidence factor of a solar heliostat receiver system.

    Science.gov (United States)

    Wei, L Y

    1980-09-15

    A general formula is derived for the effective incidence factor of an array of heliostat mirrors for solar power collection. The formula can be greatly simplified for arrays of high symmetry and offers quick computation of the performance of the array. It shows clearly how the mirror distribution and locations affect the overall performance and thus provide a useful guidance for the design of a solar heliostat receiver system.

  2. Two Schemes of Blind MMSE Multiuser Receiver for Space-Time Coded CDMA Systems

    Institute of Scientific and Technical Information of China (English)

    LU Min; XU Chang-jiang; FENG Guang-zeng

    2004-01-01

    Minimum Mean Square Error (MMSE) multiuser detection yields the highest output SINR among all linear detectors. The blind MMSE linear detector can be implemented with batch processes or sequential processes. In this paper, according to the different implementations of blind detectors, the authors analyze two schemes of the blind MMSE multiuser receiver for space-time coded CDMA Systems and make a comparison between both schemes by the theoretical analysis and numerical simulations.

  3. Solar Central Receiver Hybrid Power Systems sodium-cooled receiver concept. Final report. Volume II, Book 2. Conceptual design, Sections 5 and 6

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-01-01

    The overall, long-term objective of the Solar Central Receiver Hybrid Power System program is to identify, characterize, and ultimately demonstrate the viability and cost effectiveness of solar/fossil, steam Rankine cycle, hybrid power systems that: (1) consist of a combined solar central receiver energy source and a nonsolar energy source at a single, common site, (2) may operate in the base, intermediate, and peaking capacity modes, (3) produce the rated output independent of variations in solar insolation, (4) provide a significant savings (50% or more) in fuel consumption, and (5) produce power at the minimum possible cost in mills/kWh. It is essential that these hybrid concepts be technically feasible and economically competitive with other systems in the near to mid-term time period (1985-1990) on a commercial scale. The program objective for Phase I is to identify and conceptually characterize solar/fossil steam Rankine cycle, commercial-scale, power plant systems that are economically viable and technically feasible. This volume contains the detailed conceptual design and cost/performance estimates and an assessment of the commercial scale solar central receiver hybrid power system. (WHK)

  4. Millimeter wavelength spectroscopy of trace atmospheric constituents from the Five College Radio Astronomy Observatory

    Science.gov (United States)

    Huguenin, G. R.; Irvine, W. M.

    1978-01-01

    The Five College Radio Astronomy Observatory system, located in western Massachusetts, is described. It is suggested that high sensitivity in the three-millimeter wavelength band facilitates detection and monitoring of a number of trace molecules in the earth's atmosphere as well as astonomical observation at radio wavelengths. Line formation and radiative transfer in the earth's atmosphere are discussed, and the receiver sensitivity is considered.

  5. Performance Analysis of Ultra Wideband Receivers for High Data Rate Wireless Personal Area Network System

    CERN Document Server

    Das, Bikramaditya; 10.5121/jgraphhoc.2010.2104

    2010-01-01

    For high data rate ultra wideband communication system, performance comparison of Rake, MMSE and Rake-MMSE receivers is attempted in this paper. Further a detail study on Rake-MMSE time domain equalizers is carried out taking into account all the important parameters such as the effect of the number of Rake fingers and equalizer taps on the error rate performance. This receiver combats inter-symbol interference by taking advantages of both the Rake and equalizer structure. The bit error rate performances are investigated using MATLAB simulation on IEEE 802.15.3a defined UWB channel models. Simulation results show that the bit error rate probability of Rake-MMSE receiver is much better than Rake receiver and MMSE equalizer. Study on non-line of sight indoor channel models illustrates that bit error rate performance of Rake-MMSE (both LE and DFE) improves for CM3 model with smaller spread compared to CM4 channel model. It is indicated that for a MMSE equalizer operating at low to medium SNR values, the number o...

  6. A software radio approach to global navigation satellite system receiver design

    Science.gov (United States)

    Akos, Dennis Matthew

    1997-12-01

    The software radio has been described as the most significant evolution in receiver design since the development of the superheterodyne concept in 1918. The software radio design philosophy is to position an analog-to-digital converter (ADC) as close to the antenna as possible and then process the samples using a combination of software and a programmable microprocessor. There are a number of important advantages to be gained through full exploitation of the software radio concept. The most notable include: (1) The removal of analog signal processing components and their associated nonlinear, temperature-based, and age-based performance characteristics. (2) A single antenna/front-end configuration can be used to receive and demodulate a variety of radio frequency (RF) transmissions. (3) The software radio provides the ultimate simulation/testing environment. Global Navigation Satellite Systems (GNSSs) are the latest and most complex radionavigation systems in widespread use. The United States' Global Positioning System (GPS) and, to a lesser extent, the Russian Global Orbiting Navigation Satellite System (GLONASS) are being targeted for use as next generation aviation navigation systems. As a result, it is critical that a GNSS achieve the reliability and integrity necessary for use within the aerospace system. The receiver design is a key element in achieving the high standards required. This work presents the complete development of a GNSS software radio. A GNSS receiver front end has been constructed, based on the software radio design goals, and has been evaluated against the traditional design. Trade-offs associated with each implementation are presented along with experimental results. Novel bandpass sampling front end designs have been proposed, implemented and tested for the processing of multiple GNSS transmissions. Finally, every aspect of GNSS signal processing has been implemented in software from the necessary spread spectrum acquisition algorithms to

  7. The radio astronomy experiment on Helios A and B /E 5c/. [using dipole antenna-preamplifier-radiometer system

    Science.gov (United States)

    Weber, R. R.

    1975-01-01

    The NASA Goddard Space Flight Center radio astronomy experiment on Helios, identified as Experiment 5c, has sixteen observing frequencies over the range of 26.5 to 3000 kHz. The antenna consists of two extendible 15-m booms, forming an electric dipole, two high-impedance preamplifiers located at the root of the booms, and the 16-channel radiometer. Important information about propagation conditions, such as absorption, scattering and refraction, are expected from observations of radio emission regions at distances between 1 and 0,3 AU.

  8. Inquiry and Epistemology in Astronomy: Examination of middle school students’ epistemological beliefs and learning about the Earth-Moon system

    Science.gov (United States)

    Taylor, Roger S.; Grundstrom, E. D.

    2009-12-01

    Over two thousand years ago, the Greek scholar Eratosthenes performed an elegant experiment in which he accurately calculated the size of the Earth through the use of geometry and the measurement of the length of a shadow. The authors conducted an empirical study in which middle school students engaged in the authentic inquiry task of replicating Eratosthenes’ experiment. It was hypothesized that engagement in this instructional intervention would lead to both increased knowledge about astronomy, as well as more sophisticated views about the nature of science.

  9. Comprehensive Reactive Receiver Modeling for Diffusive Molecular Communication Systems: Reversible Binding, Molecule Degradation, and Finite Number of Receptors

    CERN Document Server

    Ahmadzadeh, Arman; Burkovski, Andreas; Schober, Robert

    2016-01-01

    This paper studies the problem of receiver modeling in molecular communication systems. We consider the diffusive molecular communication channel between a transmitter nano-machine and a receiver nano-machine in a fluid environment. The information molecules released by the transmitter nano-machine into the environment can degrade in the channel via a first-order degradation reaction and those that reach the receiver nano-machine can participate in a reversible bimolecular reaction with receiver receptor proteins. Thereby, we distinguish between two scenarios. In the first scenario, we assume that the entire surface of the receiver is covered by receptor molecules. We derive a closed-form analytical expression for the expected received signal at the receiver, i.e., the expected number of activated receptors on the surface of the receiver. Then, in the second scenario, we consider the case where the number of receptor molecules is finite and the uniformly distributed receptor molecules cover the receiver surfa...

  10. The Concise Knowledge Astronomy

    Science.gov (United States)

    Clerke, Agnes Mary; Fowler, Alfred; Ellard Gore, John

    2011-01-01

    Preface; Section I. History Agnes M. Clerke: 1. From Hipparchus to Laplace; 2. A century of progress; Section II. Geometrical Astronomy and Astronomical Instruments A. Fowler: 1. The Earth and its rotation; 2. The Earth's revolution round the Sun; 3. How the positions of the heavenly bodies are defined; 4. The Earth's orbit; 5. Mean solar time; 6. The movements of the Moon; 7. Movements of planets, satellites, and comets; 8. Eclipses and occultations; 9. How to find our situation on the Earth; 10. The exact size and shape of the earth; 11. The distances and dimensions of the heavenly bodies; 12. The masses of celestial bodies; 13. Gravitational effects of Sun and moon upon the Earth; 14. Instrumental measurement of angles and time; 15. Telescopes; 16. Instruments of precision; 17. Astrophysical instruments; Section III. The Solar System Agnes M. Clerke: 1. The solar system as a whole; 2. The Sun; 3. The Sun's surroundings; 4. The interior planets; 5. The Earth and Moon; 6. The planet Mars; 7. The asteroids; 8. The planet Jupiter; 9. The Saturnian system; 10. Uranus and Neptune; 11. Famous comets; 12. Nature and origin of comets; 13. Meteorites and shooting stars; Section IV. The Sidereal Heavens J.E. Gore: 1. The stars and constellations; 2. Double, multiple, and coloured stars; 3. The distances and motions of the stars; 4. Binary stars; 5. Variable and temporary stars; 6. Clusters and nebulae; 7. The construction of the heavens; Index.

  11. Astronomy, Astrology, and Medicine

    Science.gov (United States)

    Greenbaum, Dorian Gieseler

    Astronomy and astrology were combined with medicine for thousands of years. Beginning in Mesopotamia in the second millennium BCE and continuing into the eighteenth century, medical practitioners used astronomy/astrology as an important part of diagnosis and prescription. Throughout this time frame, scientists cited the similarities between medicine and astrology, in addition to combining the two in practice. Hippocrates and Galen based medical theories on the relationship between heavenly bodies and human bodies. In an enduring cultural phenomenon, parts of the body as well as diseases were linked to zodiac signs and planets. In Renaissance universities, astronomy and astrology were studied by students of medicine. History records a long tradition of astrologer-physicians. This chapter covers the topic of astronomy, astrology, and medicine from the Old Babylonian period to the Enlightenment.

  12. Cultural Astronomy in Japan

    Science.gov (United States)

    Renshaw, Steven L.

    While Japan is known more for its contributions to modern astronomy than its archaeoastronomical sites, there is still much about the culture's heritage that is of interest in the study of cultural astronomy. This case study provides an overview of historical considerations necessary to understand the place of astronomy in Japanese society as well as methodological considerations that highlight traditional approaches that have at times been a barrier to interdisciplinary research. Some specific areas of study in the cultural astronomy of Japan are discussed including examples of contemporary research based on interdisciplinary approaches. Japan provides a fascinating background for scholars who are willing to go beyond their curiosity for sites of alignment and approach the culture with a desire to place astronomical iconography in social context.

  13. Astronomy in Second Life

    Directory of Open Access Journals (Sweden)

    Gauthier, A.

    2007-10-01

    Full Text Available Second Life (SL is a multi-user virtual environment that is not limited to adult social entertainment. SL is also a 3D playground for innovative instructors and education/outreach professionals in the sciences. Astronomy and space science have a presence in SL, but it could be so much more. This paper describes some of the current astronomy themed spaces in SL and briefly discusses future innovations.

  14. Development of an integrated heat pipe-thermal storage system for a solar receiver

    Science.gov (United States)

    Keddy, E.; Sena, J. Tom; Merrigan, M.; Heidenreich, Gary; Johnson, Steve

    1988-01-01

    An integrated heat pipe-thermal storage system was developed as part of the Organic Rankine Cycle Solar Dynamic Power System solar receiver for space station application. The solar receiver incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain thermal energy storage (TES) canisters within the vapor space with a toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the earth orbit, solar energy is delivered to the heat pipe. Part of this thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of earth orbit, the stored energy in the TES units is transferred by the potassium vapor to the toluene heater tube. A developmental heat pipe element was constructed that contains axial arteries and a distribution wick connecting the toluene heater and the TES units to the solar insolation surface of the heat pipe. Tests were conducted to demonstrate the heat pipe, TES units, and the heater tube operation. The heat pipe element was operated at design input power of 4.8 kW. Thermal cycle tests were conducted to demonstrate the successful charge and discharge of the TES units. Axial power flux levels up to 15 watts/sq cm were demonstrated and transient tests were conducted on the heat pipe element. Details of the heat pipe development and test procedures are presented.

  15. Shannon's secrecy system with informed receivers and its application to systematic coding for wiretapped channels

    CERN Document Server

    Merhav, Neri

    2007-01-01

    Shannon's secrecy system is studied in a setting, where both the legitimate decoder and the wiretapper have access to side information sequences correlated to the source, but the wiretapper receives both the coded information and the side information via channels that are more noisy than the respective channels of the legitmate decoder, which in turn, also shares a secret key with the encoder. A single--letter characterization is provided for the achievable region in the space of five figures of merit: the equivocation at the wiretapper, the key rate, the distortion of the source reconstruction at the legitimate receiver, the bandwidth expansion factor of the coded channels, and the average transmission cost (generalized power). Beyond the fact that this is an extension of earlier studies, it also provides a framework for studying fundamental performance limits of systematic codes in the presence of a wiretap channel. The best achievable performance of systematic codes is then compared to that of a general co...

  16. Pilot Signal Design for Massive MIMO Systems: A Received Signal-To-Noise-Ratio-Based Approach

    Science.gov (United States)

    So, Jungho; Kim, Donggun; Lee, Yuni; Sung, Youngchul

    2015-05-01

    In this paper, the pilot signal design for massive MIMO systems to maximize the training-based received signal-to-noise ratio (SNR) is considered under two channel models: block Gauss-Markov and block independent and identically distributed (i.i.d.) channel models. First, it is shown that under the block Gauss-Markov channel model, the optimal pilot design problem reduces to a semi-definite programming (SDP) problem, which can be solved numerically by a standard convex optimization tool. Second, under the block i.i.d. channel model, an optimal solution is obtained in closed form. Numerical results show that the proposed method yields noticeably better performance than other existing pilot design methods in terms of received SNR.

  17. Iterative Multiuser Receiver Based on Factor Graph for Asynchronous Coded CDMA Systems

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Factor graph, so named because it graphically represents function factorization, with which and its sum-product algorithm the iterative algorithm can be derived clearly. An iterative multiuser receiver based on factor graph for asynchronous coded CDMA system is proposed. In this paper, the a posteriori probability of users information bits conditioned on the noise-whitening filters output is represented by factor graphs, after numbers of iterations with the sum-product algorithm the information bits are estimated. The authors also propose a reduced complexity algorithm. Simulation results show that with this proposed receiver, near-single-user performance can be achieved, and small performance degradation for the reduced complexity algorithm with significant complexity reduction.

  18. Bad Astronomy Goes Hollywood

    Science.gov (United States)

    Plait, P.

    2003-05-01

    It can be argued that astronomy is the oldest of all the sciences, so you'd think that after all this time people would have a pretty good understanding of it. In reality, however, misconceptions about astronomy abound, and even basic concepts are misunderstood. There are many sources of these cosmic misconceptions, including incorrect textbooks, parents and/or teachers who don't understand astronomy and therefore spread misinformation, urban legends, and so on. Perhaps the most pervasive source of bad astronomy is Hollywood. Science fiction movies are enormously popular, but are commonly written and directed by people who don't have even a passing familiarity with astronomy. The smash hit "Armageddon" (the number one box office movie of 1998), for example, used vast quantities of incorrect astronomy in the plot. It reinforced such popular misconceptions as huge asteroids impacting the Earth with little warning, small meteorites being hot when they impact, air existing in space, and that a simple bomb can blow up an asteroid the size of a small moon (even when the bomb is buried only 800 feet deep!). However, movie scenes can be used as a hook that engages the student, helping them learn and remember the correct science. In this talk, I will light-heartedly discuss specific examples of common misinformation, using movie clips, diagrams, and a splash of common sense to show just where Hollywood gets it wrong, and what you can do to help students and the public get it right.

  19. Evaluation of the variability of wind speed at different heights and its impact on the receiver efficiency of central receiver systems

    Science.gov (United States)

    Delgado, A.; Gertig, C.; Blesa, E.; Loza, A.; Hidalgo, C.; Ron, R.

    2016-05-01

    Typical plant configurations for Central Receiver Systems (CRS) are comprised of a large field of heliostats which concentrate solar irradiation onto the receiver, which is elevated hundreds of meters above the ground. Wind speed changes with altitude above ground, impacting on the receiver thermal efficiency due to variations of the convective heat losses. In addition, the physical properties of air vary at high altitudes to a significant degree, which should be considered in the thermal losses calculation. DNV GL has long-reaching experience in wind energy assessment with reliable methodologies to reduce the uncertainty of the determination of the wind regime. As a part of this study, DNV GL estimates the wind speed at high altitude for different sites using two methods, a detailed estimation applying the best practices used in the wind energy sector based on measurements from various wind sensors and a simplified estimation applying the power law (1, 2) using only one wind measurement and a representative value for the surface roughness. As a result of the study, a comparison of the wind speed estimation considering both methods is presented and the impact on the receiver performance for the evaluated case is estimated.

  20. Long Length Contaminated Equipment Retrieval System Receiver Trailer and Transport Trailer Operations and Maintenance Manual

    Energy Technology Data Exchange (ETDEWEB)

    DALE, R.N.

    2000-05-01

    A system to accommodate the removal of long-length contaminated equipment (LLCE) from Hanford underground radioactive waste storage tanks was designed, procured, and demonstrated, via a project activity during the 1990s. The system is the Long Length Contaminated Equipment Removal System (LLCERS). LLCERS will be maintained and operated by Tank Farms Engineering and Operations organizations and other varied projects having a need for the system. The responsibility for the operation and maintenance of the LLCERS Receiver Trailer (RT) and Transport Trailer (TT) resides with the RPP Characterization Project Operations organization. The purpose of this document is to provide vendor supplied operating and maintenance (O & M) information for the RT and TT in a readily retrievable form. This information is provided this way instead of in a vendor information (VI) file to maintain configuration control of the operations baseline as described in RPP-6085, ''Configuration Management Plan for Long Length Contaminated Equipment Receiver and Transport Trailers''. Additional Operations Baseline documents are identified in RPP-6085.

  1. Long Length Contaminated Equipment Retrieval System Receiver Trailer and Transport Trailer Operations and Maintenance Manual

    International Nuclear Information System (INIS)

    A system to accommodate the removal of long-length contaminated equipment (LLCE) from Hanford underground radioactive waste storage tanks was designed, procured, and demonstrated, via a project activity during the 1990s. The system is the Long Length Contaminated Equipment Removal System (LLCERS). LLCERS will be maintained and operated by Tank Farms Engineering and Operations organizations and other varied projects having a need for the system. The responsibility for the operation and maintenance of the LLCERS Receiver Trailer (RT) and Transport Trailer (TT) resides with the RPP Characterization Project Operations organization. The purpose of this document is to provide vendor supplied operating and maintenance (O and M) information for the RT and TT in a readily retrievable form. This information is provided this way instead of in a vendor information (VI) file to maintain configuration control of the operations baseline as described in RPP-6085, ''Configuration Management Plan for Long Length Contaminated Equipment Receiver and Transport Trailers''. Additional Operations Baseline documents are identified in RPP-6085

  2. Geoscience Laser Altimeter System: Characteristics and Performance of the Altimeter Receiver

    Science.gov (United States)

    Sun, Xiao-Li; Yi, Dong-Hui; Abshire, James B.

    2003-01-01

    The Geoscience Laser Altimeter System (GLAS) on board ICESat spacecraft measures the surface height (altimetry) via the time of flight of its 1064 nm laser pulse. The GLAS laser transmitter produces 6 ns wide pulses with 70 mJ energy at 1064 nm at a 40 Hz rate. The altimeter receiver consists of a telescope, aft optics, a silicon avalanche photodiode, and electronic amplifiers. The transmitted and echo pulse waveforms are digitized at 1 GHz rate. The laser pulse time of flight is determined on the ground from the two digitized pulse waveforms and their positions in the full waveform record (about 5.4 ms ong) by computing the pulse centroids or by curve fitting. The GLAS receiver algorithms in on board software selects the two waveform segments containing the transmitted and the echo pulses and sends them to ground. The probability of echo pulse detection and the accuracy of time of flight measurement depend on the received signal level, the background light within the receiver field of view, the inherent detector and amplifier noise, the quantization of the digitizer, and some times by cloud obscurations. A receiver model has been developed to calculate the probability of detection and accuracy of the altimeter measurements with these noise sources. From prelaunch testing, the minimum detectable echo pulse energy for 90% detection probability was about 0.1 fj/pulse onto the detector. Such a receiver sensitivity allows GLAS to measure the surface height through clouds with optical density less than 2. The echo pulse energy required to achieve 10 cm ranging accuracy was found to be about 3 times higher than the minimum detectable signal level. The smallest single shot range measurement error, which was determined by ranging to a fixed target with strong echo pulses and no background light, was 2 to 3cm. The maximum linear response echo pulse energy was 10 fJ/pulse for the strongest echo signals, assuming a Lambertian scattering snow surface, clear sky atmosphere

  3. Geoscience Laser Altimeter System - Characteristics and Performance of the Altimeter Receiver

    Science.gov (United States)

    Sun, X.; Abshire, J. B.; Yi, D.

    2003-12-01

    The Geoscience Laser Altimeter System (GLAS) on board ICESat spacecraft measures the surface height (altimetry) via the time of flight of its 1064 nm laser pulse. The GLAS laser transmitter produces 6 ns wide pulses with 70 mJ energy at 1064 nm at a 40 Hz rate. The altimeter receiver consists of a telescope, aft optics, a silicon avalanche photodiode, and electronic amplifiers. The transmitted and echo pulse waveforms are digitized at 1 GHz rate. The laser pulse time of flight is determined on the ground from the two digitized pulse waveforms and their positions in the full digital waveform record (about 5.4 ms long) by computing the pulse centroids or by curve fitting. The GLAS receiver algorithms in on board software selects the two waveform segments containing the transmitted and the echo pulses and sends them to ground. The probability of echo pulse detection and the accuracy of time of flight measurement depend on the received signal level, the background light within the receiver field of view, the inherent detector and amplifier noise, the quantization of the digitizer, and some times by cloud obscurations. A receiver model has been developed to calculate the probability of detection and accuracy of the altimeter measurements with these noise sources. From pre-launch testing, the minimum detectable echo pulse energy for 90% detection probability was about 0.1 fJ/pulse onto the detector. Such a receiver sensitivity allows GLAS to measure the surface height through clouds with optical density less than 2. The echo pulse energy required to achieve 10cm ranging accuracy was found to be about 3 times higher than the minimum detectable signal level. The smallest single shot range measurement error, which was determined by ranging to a fixed target with strong echo pulses and no background light, was 2 to 3cm. The maximum linear response echo pulse energy was 10 fJ/pulse for the strongest echo signals, assuming a Lambertian scattering snow surface, clear sky

  4. Multi-transmitter multi-receiver null coupled systems forinductive detection and characterization of metallic objects

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J. Torquil; Morrison, H. Frank; Doolittle, Lawrence R.; Tseng, Hung-Wen

    2005-10-17

    Equivalent dipole polarizabilities are a succinct way tosummarize the inductive response of an isolated conductive body atdistances greater than the scale of the body. Their estimation requiresmeasurement of secondary magnetic fields due to currents induced in thebody by time varying magnetic fields in at least three linearlyindependent (e.g., orthogonal) directions. Secondary fields due to anobject are typically orders of magnitude smaller than the primaryinducing fields near the primary field sources (transmitters). Receivercoils may be oriented orthogonal to primary fields from one or twotransmitters, nulling their response to those fields, but simultaneouslynulling to fields of additional transmitters is problematic. Iftransmitter coils are constructed symmetrically with respect to inversionin a point, their magnetic fields are symmetric with respect to thatpoint. If receiver coils are operated in pairs symmetric with respect toinversion in the same point, then their differenced output is insensitiveto the primary fields of any symmetrically constructed transmitters,allowing nulling to three (or more) transmitters. With a sufficientnumber of receivers pairs, object equivalent dipole polarizabilities canbe estimated in situ from measurements at a single instrument sitting,eliminating effects of inaccurate instrument location on polarizabilityestimates. The method is illustrated with data from a multi-transmittermulti-receiver system with primary field nulling through differencedreceiver pairs, interpreted in terms of principal equivalent dipolepolarizabilities as a function of time.

  5. Advanced Receiver Design for Mitigating Multiple RF Impairments in OFDM Systems: Algorithms and RF Measurements

    Directory of Open Access Journals (Sweden)

    Adnan Kiayani

    2012-01-01

    Full Text Available Direct-conversion architecture-based orthogonal frequency division multiplexing (OFDM systems are troubled by impairments such as in-phase and quadrature-phase (I/Q imbalance and carrier frequency offset (CFO. These impairments are unavoidable in any practical implementation and severely degrade the obtainable link performance. In this contribution, we study the joint impact of frequency-selective I/Q imbalance at both transmitter and receiver together with channel distortions and CFO error. Two estimation and compensation structures based on different pilot patterns are proposed for coping with such impairments. The first structure is based on preamble pilot pattern while the second one assumes a sparse pilot pattern. The proposed estimation/compensation structures are able to separate the individual impairments, which are then compensated in the reverse order of their appearance at the receiver. We present time-domain estimation and compensation algorithms for receiver I/Q imbalance and CFO and propose low-complexity algorithms for the compensation of channel distortions and transmitter IQ imbalance. The performance of the compensation algorithms is investigated with computer simulations as well as with practical radio frequency (RF measurements. The performance results indicate that the proposed techniques provide close to the ideal performance both in simulations and measurements.

  6. Solar Central Receiver Hybrid Power Systems sodium-cooled receiver concept. Final report. Volume II, Book 1. Conceptual design, Sections 1 through 4

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-01-01

    The overall, long-term objective of the Solar Central Receiver Hybrid Power System program is to identify, characterize, and ultimately demonstrate the viability and cost effectiveness of solar/fossil, steam Rankine cycle, hybrid power systems that: (1) consist of a combined solar central receiver energy source and a nonsolar energy source at a single, common site, (2) may operate in the base, intermediate, and peaking capacity modes, (3) produce the rated output independent of variations in solar insolation, (4) provide a significant savings (50% or more) in fuel consumption, and (5) produce power at the minimum possible cost in mills/kWh. It is essential that these hybrid concepts be technically feasible and economically competitive with other systems in the near to mid-term time period (1985-1990) on a commercial scale. The program objective for Phase I is to identify and conceptually characterize solar/fossil steam Rankine cycle, commercial-scale, power plant systems that are economically viable and technically feasible. This volume presents in detail the market analysis, parametric analysis, and the selection process for the preferred system. (WHK)

  7. Improved Iterative Parallel Interference Cancellation Receiver for Future Wireless DS-CDMA Systems

    Directory of Open Access Journals (Sweden)

    Andrea Bernacchioni

    2005-04-01

    Full Text Available We present a new turbo multiuser detector for turbo-coded direct sequence code division multiple access (DS-CDMA systems. The proposed detector is based on the utilization of a parallel interference cancellation (PIC and a bank of turbo decoders. The PIC is broken up in order to perform interference cancellation after each constituent decoder of the turbo decoding scheme. Moreover, in the paper we propose a new enhanced algorithm that provides a more accurate estimation of the signal-to-noise-plus-interference-ratio used in the tentative decision device and in the MAP decoding algorithm. The performance of the proposed receiver is evaluated by means of computer simulations for medium to very high system loads, in AWGN and multipath fading channel, and compared to recently proposed interference cancellation-based iterative MUD, by taking into account the number of iterations and the complexity involved. We will see that the proposed receiver outperforms the others especially for highly loaded systems.

  8. Sender-receiver systems and applying information theory for quantitative synthetic biology.

    Science.gov (United States)

    Barcena Menendez, Diego; Senthivel, Vivek Raj; Isalan, Mark

    2015-02-01

    Sender-receiver (S-R) systems abound in biology, with communication systems sending information in various forms. Information theory provides a quantitative basis for analysing these processes and is being applied to study natural genetic, enzymatic and neural networks. Recent advances in synthetic biology are providing us with a wealth of artificial S-R systems, giving us quantitative control over networks with a finite number of well-characterised components. Combining the two approaches can help to predict how to maximise signalling robustness, and will allow us to make increasingly complex biological computers. Ultimately, pushing the boundaries of synthetic biology will require moving beyond engineering the flow of information and towards building more sophisticated circuits that interpret biological meaning.

  9. Influence of transmitter chirp and receiver imperfections on RF gain in short-range ROMMF systems

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal; Tartarini, Giovanni; Visani, Davide;

    2011-01-01

    Two important effects that can lead to extensive detrimental effects on short-range radio-over-multimode-fiber systems are presented. The work experimentally shows how transmitter chirp and receiver imperfections determine the degree of both small signal RF variations as well as optical power var...... variations. Both theoretical and experimental results conclude that without taking proper precautions in designing even short-range links, the potential power variations can reach more than 5 dB over just 150m multimode-fiber....

  10. The effect of concentrator field layout on the performance of point-focus distributed receiver systems

    Science.gov (United States)

    Pons, R. L.; Dugan, A. F.

    1984-01-01

    The effect of concentrator field layout on the technical-economic performance of a point-focusing distributed receiver (PFDR) solar thermal power plant is presented. The plant design is based on the small community prototype system currently under development for JPL/DOE; parabolic dish concentrators are employed, and small heat engines are used to generate electricity at each dish. The effect of field size, array proportions, dish-to-dish spacing and packing fraction (concentrator-land area ratio) are presented for typical PFDR layouts. Economic analyses are carried out to determine optimum packing fraction as a function of site cost.

  11. The history of astronomy a very short introduction

    CERN Document Server

    Hoskin, Michael

    2003-01-01

    The History of Astronomy: A Very Short Introduction traces the history of Western astronomy, from prehistoric times to the origins of astrophysics in the mid-nineteenth century and the technical developments since the Second World War. Astronomy, perhaps the first of the sciences, was already well developed by the time of Christ — the arithmetical astronomy of the Babylonians was merged with the Greek geometrical approach. This legacy was transmitted to the West via Islam and led to the Copernican revolution, which in turn led to Kepler and Newton, who provided the principles on which the exploration of the solar system and the stars continued in the eighteenth- and nineteenth centuries.

  12. Astronomy from the chair - the application of the Internet in promoting of Astronomy

    Science.gov (United States)

    Tomic, Zoran

    2014-05-01

    Internet and modern communication technologies are an indispensable part of modern life. The use of the Internet makes it possible to enhance the education and expand opportunities for acquiring new knowledge. One example is Astronomy, where today thanks to the Internet, we can control telescopes that are distant from us and listen to lectures from Universities in other countries. "Astronomy from the chair" is the name for a concept where amateur astronomers can deal with astronomy from their homes using the Internet. The concept can be divided into four sections depending on the content being offered: Robotic Observatory, Virtual Observatory, Online astronomy broadcasting and Online courses. Robotic observatory is defined as an astronomical instrument and detection system that enables efficient observation without the need of a person's physical intervention. Virtual Observatory is defined as a collection of databases and software tools that use the Internet as a platform for scientific research. Online astronomy broadcasting is part of concept "Astronomy from the chair" which gives users the opportunity to get directly involved in astronomical observation organized by an amateur astronomer from somewhere in the world. Online courses are groups of sites and organizations that provide the opportunity to amateur astronomers to attend lectures, save and watch video materials from lectures, do homework, communicate with other seminar participants and in that way become familiar with the various areas of Astronomy. This paper discusses a new concept that describes how the Internet can be applied in modern education. In this paper will be described projects that allows a large number of astronomy lovers to do their own research without the need to own a large and expensive set of astronomical equipment (Virtual Telescope from Italy, Observatory "Night Hawk" from Serbia and project "Astronomy from an armchair" at Faculty of Sciences and Mathematics in Nis), to help

  13. 30 CFR 77.703 - Grounding frames of stationary high-voltage equipment receiving power from ungrounded delta systems.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding frames of stationary high-voltage equipment receiving power from ungrounded delta systems. 77.703 Section 77.703 Mineral Resources MINE SAFETY... stationary high-voltage equipment receiving power from ungrounded delta systems. The frames of all...

  14. High-temperature thermal storage systems for advanced solar receivers materials selections

    Science.gov (United States)

    Wilson, D. F.; Devan, J. H.; Howell, M.

    1990-01-01

    Advanced space power systems that use solar energy and Brayton or Stirling heat engines require thermal energy storage (TES) systems to operate continuously through periods of shade. The receiver storage units, key elements in both Brayton and Stirling systems, are designed to use the latent heat of fusion of phase-change materials (PCMs). The power systems under current consideration for near-future National Aeronautics and Space Administration space missions require working fluid temperatures in the 1100 to 1400 K range. The PCMs under current investigation that gave liquid temperatures within this range are the fluoride family of salts. However, these salts have low thermal conductivity, which causes large temperature gradients in the storage systems. Improvements can be obtained, however, with the use of thermal conductivity enhancements or metallic PCMs. In fact, if suitable containment materials can be found, the use of metallic PCMs would virtually eliminate the orbit associated temperature variations in TES systems. The high thermal conductivity and generally low volume change on melting of germanium and alloys based on silicon make them attractive for storage of thermal energy in space power systems. An approach to solving the containment problem, involving both chemical and physical compatibility, preparation of NiSi/NiSi2, and initial results for containment of germanium and NiSi/NiSi2, are presented.

  15. Andrea Ghez Receives Crafoord Prize

    OpenAIRE

    Sher, Ben

    2012-01-01

    The Royal Swedish Academy of Scienceshas selected Andrea Ghez, a professor of physics and astronomy at UCLA, to receive the 2012 Crafoord Prize in Astronomy. She is being honored by the Academy for “observations of stars orbiting the Galactic center, indicating the presence of a supermassive black hole.” The Crafoord Prize, which includes an accompanying award of 4 million Swedish krona, is considered one of the world’s largest scientific prizes. Ghez is the first woman to win the award since...

  16. Astronomy in Colombia

    Science.gov (United States)

    Cepeda-Peña, W. E.

    2006-08-01

    Astronomy in Colombia has been done since the beginning of the nineteen century when in 1803 was built one of the oldest or maybe the older astronomical Observatory of America. This is a very beautiful, historical and ancient building. A small dome with a small telescope is also inside the university campus . The Observatory leads since then the development of astronomy in Colombia as a professional science. At the present time a Master Program and a Specialization Program are successfully carried out with a good number of smart young students. The Observatory has a staff of eleven professors all with a master degree in sciences; two of them are PhD and in a couple of years five staff members will be PhD in Physics. With some international collaboration they will shoulder in few years a doctoral astronomical program. There are several research lines mainly in the fields of Astrometry, Galactic and Extragalactic Astronomy, Cosmology, Astrostatistic and Astrobiology. Three research groups have got recognition from the governmental institution that supports the research in sciences COLCIENCIAS. Several papers have been published in national and international journals. Besides the professional line in astronomy, the Observatory sponsors several non professional Colombian astronomical groups that work enthusiastically in the field of astronomy.

  17. Astronomy in Culture

    Science.gov (United States)

    Stavinschi, M.

    2010-07-01

    Which is more appropriate? “Astronomy in culture,” or “Astronomy and culture,” or “Culture without astronomy?” These are only few variants, each with its own sense. I guess the last question is the most pertinent. Does culture really exist without astronomy? The existence and evolution of the human civilization answer NO! But what “culture” means? When we are thinking of a culture (the Hellenistic one, for instance), we mean a set of customs, artistic, religious, intellectual manifestations that differentiate one group or society from another. On the other hand, we often use the notion of culture in a different sense: shared beliefs, ways of regarding and doing, which orient more or less consciously the behavior of an individual or a group. An example would be the laic culture. Moreover, the set of knowledge acquired in one or several domains also constitutes a culture, for instance the scientific culture of an individual or a group. Finally, the set of cultures is nothing else but the civilization. Now, if we come back in time into the history of civilization, we find a permanent component, which was never missing and often played a decisive part in its evolution: the Astronomy.

  18. Conceptual design of an RTG shipping and receiving facility transportation system

    International Nuclear Information System (INIS)

    The conceptual design of an RTG Facility Transportation System which is part of the overall RTG Transportation System has been completed and is described in detail. The Facility Transportation System serves to provide locomotion, cooling, shock protection and data acquisition for the RTG package during onloading and offloading sequences. The RTG Shipping ampersand Receiving Facility Transportation System consists of a Transporter Subsystem, a Package Cooling Subsystem, and a Shock Limiting Transit Device Subsystem. The Transporter Subsystem is a custom designed welded steel cart combined with a pneumatically-driven hand tug for locomotion. The Package Cooling Subsystem provides five kilowatts of active liquid cooling via an on-board refrigeration system. The Shock Limiting Transit Device Subsystem consists of a consumable honeycomb anti-shock frame which provides shock protection for the 3855 kg (8500 LB) RTG package. These subsystems have been combined into an integrated system which will facilitate the offloading and onloading of the RTG Package into and out of the semitrailer as well as meet ALARA (as low as reasonably achievable) radiation exposure guidelines. copyright 1995 American Institute of Physics

  19. Conceptual design of an RTG Shipping and Receiving Facility Transportation System

    International Nuclear Information System (INIS)

    The conceptual design of an RTG Facility Transportation System which is part of the overall RTG Transportation System has been completed and is described in detail. The Facility Transportation System serves to provide locomotion, cooling, shock protection and data acquisition for the RTG package during onloading and offloading sequences. The RTG Shipping ampersand Receiving Facility Transportation System consists of a Transporter Subsystem, a Package Cooling Subsystem, and a Shock Limiting Transit Device Subsystem. The Transporter Subsystem is a custom designed welded steel cart combined with a pneumatically-driven hand tug for locomotion. The Package Cooling Subsystem provides five kilowatts of active liquid cooling via an on-board refrigeration system. The Shock Limiting Transit Device Subsystem consists of a consumable honeycomb anti-shock frame which provides shock protection for the 3855 kg (8500 LB) RTG package. These subsystems have been combined into an integrated system which will facilitate the offloading and onloading of the RTG Package into and out of the semitrailer as well as meet ALARA (as low as reasonably achievable) radiation exposure guidelines

  20. Performance analysis of underlay cognitive multihop regenerative relaying systems with multiple primary receivers

    KAUST Repository

    Hyadi, Amal

    2013-12-01

    Multihop relaying is an efficient strategy to improve the connectivity and extend the coverage area of secondary networks in underlay cognitive systems. In this work, we provide a comprehensive performance study of cognitive multihop regenerative relaying systems in an underlay spectrum sharing scenario with the presence of multiple primary receivers. Both interference power and peak power constraints are taken into account. In our analysis, all the links are subject to independent, non-identically distributed Nakagami-m fading. We derive closed-form expressions for the outage probability, high-order amount of fading, bit error rate, symbol error rate, and ergodic capacity. Different scenarios are presented to illustrate the obtained results and Monte Carlo simulations confirm the accuracy of our analytical derivations. © 2013 IEEE.

  1. Multi-Variable Flocking Control for Multi-Agent Systems via a Received Signal Strength Indicator

    Institute of Scientific and Technical Information of China (English)

    Xin-Ping Guan; Shao-Min Xing; Xiao-Yuan Luo

    2011-01-01

    A novel flocking control approach is proposed for multi-agent systems by integrating the variables of velocities,motion directions,and positions of agents.A received signal strength indicator (RSSI) is applied as a variable to estimate the inter-distance between agents.A key parameter that contains the local information of agents is defined,and a multi-variable controller is proposed based on the parameter.For the position control of agents,the RSSI is introduced to substitute the distance as a control variable in the systems.The advantages of RSSI include that the relative distance between every two agents can be adjusted through the communication quality under different environments,and it can shun the shortage of the limit of sensors.Simulation studies demonstrate the effectiveness of the proposed control approach.

  2. A power supply system for the receiving section in a coal cutter loader radio control unit

    Energy Technology Data Exchange (ETDEWEB)

    Mikhalchuk, U.T.; Etim, U.I.; Ivantsov, L.I.; Tsymbal, A.K.

    1981-01-01

    The purpose of this invention is to improve the operational characteristics of a power supply system and to provide spark protection to the receiving unit. This is achieved by an arrangement whereby the system is equipped with an additional charging unit, a delay circuit, a diode and a dual-input OR circuit, whose inputs are connected to the outputs from the chargers, while one output from the OR circuit is connected to the inhibiting input to the control relay in the communications channel through a delay circuit, and the other output is connected to the storage battery through a cut-off diode; the output from the additional charger is connected through the normally closed contact of the ''Stop'' final-control relay of the cutter loader and a starter to the remote control circuit.

  3. Conceptual design of advanced central receiver power systems sodium-cooled receiver concept. Volume 4. Commercial and pilot plant cost data. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    This volume of the advanced central receiver final report presents the cost data using the cost breakdown structure identified in the preliminary specification. Cost summaries are presented in the following sections for the 100-MWe and 281-MWe commercial plant and a 10-MWe pilot plant. Cost substantiation data for this volume are presented in the appendices. Other cost summary data include Nth plant data for the 100-MWe and 281-MWe commercial plants, and a summary for the alternative concept air-rock storage system. The main description of the plant costing technique occurs as part of Section II for the 100-MWe baseline concept.

  4. Low Complexity Precoder and Receiver Design for Massive MIMO Systems: A Large System Analysis using Random Matrix Theory

    KAUST Repository

    Sifaou, Houssem

    2016-05-01

    Massive MIMO systems are shown to be a promising technology for next generations of wireless communication networks. The realization of the attractive merits promised by massive MIMO systems requires advanced linear precoding and receiving techniques in order to mitigate the interference in downlink and uplink transmissions. This work considers the precoder and receiver design in massive MIMO systems. We first consider the design of the linear precoder and receiver that maximize the minimum signal-to-interference-plus-noise ratio (SINR) subject to a given power constraint. The analysis is carried out under the asymptotic regime in which the number of the BS antennas and that of the users grow large with a bounded ratio. This allows us to leverage tools from random matrix theory in order to approximate the parameters of the optimal linear precoder and receiver by their deterministic approximations. Such a result is of valuable practical interest, as it provides a handier way to implement the optimal precoder and receiver. To reduce further the complexity, we propose to apply the truncated polynomial expansion (TPE) concept on a per-user basis to approximate the inverse of large matrices that appear on the expressions of the optimal linear transceivers. Using tools from random matrix theory, we determine deterministic approximations of the SINR and the transmit power in the asymptotic regime. Then, the optimal per-user weight coe cients that solve the max-min SINR problem are derived. The simulation results show that the proposed precoder and receiver provide very close to optimal performance while reducing signi cantly the computational complexity. As a second part of this work, the TPE technique in a per-user basis is applied to the optimal linear precoding that minimizes the transmit power while satisfying a set of target SINR constraints. Due to the emerging research eld of green cellular networks, such a problem is receiving increasing interest nowadays. Closed

  5. A New Approach to Interference Excision in Radio Astronomy: Real-Time Adaptive Cancellation

    Science.gov (United States)

    Barnbaum, Cecilia; Bradley, Richard F.

    1998-11-01

    Every year, an increasing amount of radio-frequency (RF) spectrum in the VHF, UHF, and microwave bands is being utilized to support new commercial and military ventures, and all have the potential to interfere with radio astronomy observations. Such services already cause problems for radio astronomy even in very remote observing sites, and the potential for this form of light pollution to grow is alarming. Preventive measures to eliminate interference through FCC legislation and ITU agreements can be effective; however, many times this approach is inadequate and interference excision at the receiver is necessary. Conventional techniques such as RF filters, RF shielding, and postprocessing of data have been only somewhat successful, but none has been sufficient. Adaptive interference cancellation is a real-time approach to interference excision that has not been used before in radio astronomy. We describe here, for the first time, adaptive interference cancellation in the context of radio astronomy instrumentation, and we present initial results for our prototype receiver. In the 1960s, analog adaptive interference cancelers were developed that obtain a high degree of cancellation in problems of radio communications and radar. However, analog systems lack the dynamic range, noised performance, and versatility required by radio astronomy. The concept of digital adaptive interference cancellation was introduced in the mid-1960s as a way to reduce unwanted noise in low-frequency (audio) systems. Examples of such systems include the canceling of maternal ECG in fetal electrocardiography and the reduction of engine noise in the passenger compartments of automobiles. These audio-frequency applications require bandwidths of only a few tens of kilohertz. Only recently has high-speed digital filter technology made high dynamic range adaptive canceling possible in a bandwidth as large as a few megahertz, finally opening the door to application in radio astronomy. We have

  6. Astronomy education in Thailand

    Science.gov (United States)

    Hutawarakorn, Busaba; Soonthornthum, B.; Kirdkao, T.

    Thailand is one of the developing countries which pursues the goal to advance economy, technology as well as science. Education in Astronomy is considered as a supporting factor, since it is one of the basic sciences which can teach the young generation to understand and conserve their mother nature and at the same time helps to develop analytical thinking. The poster reports the present developments in astronomical education in Thailand which includes (1) current astronomy education in school and university; (2) educational activities outside school; (3) development of programs for teaching astronomy in school (including teacher training); (4) the access of educational resources via internet. Proposals for future development and collaborations will be presented and discussed.

  7. Python in Astronomy 2016

    Science.gov (United States)

    Jenness, Tim; Robitaille, Thomas; Tollerud, Erik; Mumford, Stuart; Cruz, Kelle

    2016-04-01

    The second Python in Astronomy conference will be held from 21-25 March 2016 at the University of Washington eScience Institute in Seattle, WA, USA. Similarly to the 2015 meeting (which was held at the Lorentz Center), we are aiming to bring together researchers, Python developers, users, and educators. The conference will include presentations, tutorials, unconference sessions, and coding sprints. In addition to sharing information about state-of-the art Python Astronomy packages, the workshop will focus on improving interoperability between astronomical Python packages, providing training for new open-source contributors, and developing educational materials for Python in Astronomy. The meeting is therefore not only aimed at current developers, but also users and educators who are interested in being involved in these efforts.

  8. Astronomy Librarians - Quo Vadis?

    CERN Document Server

    Lagerstrom, Jill

    2011-01-01

    "You don't look like a librarian" is a phrase we often hear in the astronomy department or observatory library. Astronomy librarians are a breed apart, and are taking on new and non-traditional roles as information technology evolves. This talk will explore the future of librarians and librarianship through the lens of the recent talks given at the sixth "Libraries and Information Services in Astronomy" conference held in Pune, India in February 2010. We will explore the librarian's universe, illustrating how librarians use new technologies to perform such tasks as bibliometrics, how we are re-fashioning our library spaces in an increasingly digital world and how we are confronting the brave new world of open access, to name but a few topics.

  9. Radio astronomy with microspacecraft

    Science.gov (United States)

    Collins, D.

    2001-01-01

    A dynamic constellation of microspacecraft in lunar orbit can carry out valuable radio astronomy investigations in the frequency range of 30kHz--30MHz, a range that is difficult to explore from Earth. In contrast to the radio astronomy ivestigations that have flown on individual spacecraft, the four microspacecraft together with a carrier spacecraft, which transported them to lunar orbit, form an interferometer with far superior angular resolution. Use of microspacecraft allows the entire constellation to be launched with a Taurus-class vehicle. Also distinguishing this approach is that the Moon is used as needed to shield the constellation from RF interference from the Earth and Sun.

  10. Gamma-ray Astronomy

    CERN Document Server

    Hinton, Jim

    2007-01-01

    The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

  11. Astronomy in Iraq

    Science.gov (United States)

    Alsabti, A. W.

    2006-08-01

    The history of modern Iraqi astronomy is reviewed. During the early 1970's Iraqi astronomy witnessed significant growth through the introduction of the subject at university level and extensively within the school curriculum. In addition, astronomy was popularised in the media, a large planetarium was built in Baghdad, plus a smaller one in Basra. Late 1970 witnessed the construction of the Iraqi National Observatory at Mount Korek in Iraqi Kurdistan. The core facilities of the Observatory included 3.5-meter and 1.25-meter optical telescopes, and a 30-meter radio telescope for millimetre wavelength astronomy. The Iraqi Astronomical Society was founded and Iraq joined the IAU in 1976. During the regime of Saddam Hussain in the 1980's, the Observatory was attacked by Iranian artillery during the Iraq-Iran war, and then again during the second Gulf war by the US air force. Years of sanctions during the 1990's left Iraq cut off from the rest of the international scientific community. Subscriptions to astronomical journals were halted and travel to conferences abroad was virtually non-existent. Most senior astronomers left the country for one reason or another. Support from expatriate Iraqi astronomers existed (and still exists) however, this is not sufficient. Recent changes in Iraq, and the fall of Saddam's regime, has meant that scientific communication with the outside world has resumed to a limited degree. The Ministry of Higher Education in Baghdad, Baghdad University and the Iraqi National Academy of Science, have all played active roles in re-establishing Iraqi astronomy and re-building the damaged Observatory at Mount Korek. More importantly the University of Sallahudin in Erbil, capital of Iraqi Kurdistan, has taken particular interest in astronomy and the Observatory. Organized visits to the universities, and also to the Observatory, have given us a first-hand assessment of the scale of the damage to the Observatory, as well as the needs of astronomy teaching

  12. Lessons from Mayan Astronomy

    CERN Document Server

    Loeb, Abraham

    2016-01-01

    The Mayan culture collected exquisite astronomical data for over a millennium. However, it failed to come up with the breakthrough ideas of modern astronomy because the data was analyzed within a mythological culture of astrology that rested upon false but mathematically sophisticated theories about the Universe. Have we learned the necessary lessons to prevent our current scientific culture from resembling Mayan Astronomy? Clearly, data collection by itself is not a guarantee for good science as commonly assumed by funding agencies. A vibrant scientific culture should cultivate multiple approaches to analyzing existing data and to collecting new data.

  13. Single-feed superconducting circularly polarized microstrip array antenna for direct-to-home receiving system

    Energy Technology Data Exchange (ETDEWEB)

    Ali, M.I.; Ehata, K.; Ohshima, S. [Faculty of Engineering, Yamagata University, Jonan 4-3-16, Yonezawa 992-8510 (Japan)

    2000-07-01

    Single-feed circularly polarized microstrip patch and patch array antennas for 'direct-to-home' receiving system at around 12 GHz are studied by theoretical analysis and experiments. A full-wave microwave circuit simulator (Em), based on the method of moments and capable of handling the microwave surface impedance, has been used in the theoretical analysis of the antennas. Antennas have been fabricated from both normal conductor (gold) and YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) superconductor for comparison. Measured results on resonant frequency (f{sub r}), return loss, gain, bandwidth, and axial ratio are presented. The antennas are found to show a very low axial ratio and a moderate bandwidth. In the comparison of gain, the superconducting antennas showed a remarkable improvement over their gold counterparts. The receiving power of a four-element array fabricated from a single-side YBCO thin film on (100) MgO single crystal substrate is found to be 1.8 dB higher than that of a gold array with identical configuration and both measured at 77 K. (author)

  14. Astronomy on the High Seas

    Science.gov (United States)

    Hughes, S.; Rihani, N.

    2010-06-01

    This article describes the development and launching of a stargazing activity on two cruise ships, Pacific Dawn and Pacific Sun, which sail from Australian ports. The session included a presentation entitled "Voyage to the Stars" that gave passengers an overview of the life cycle of stars from star-birth nebulae to white dwarfs and black holes. In the presentation it was noted that ancient mariners used the celestial sphere to navigate. The presentation was followed by on-deck observing sessions in which objects shown in the presentation were viewed with the naked eye, binoculars and a small telescope. The activity seemed to be well received and resulted in numerous questions to the presenter of the activity. Many people said that the activity had kindled or rekindled their interest in astronomy.

  15. Open Access Publishing in Astronomy

    Science.gov (United States)

    Grothkopf, U.; Meakins, S.

    2012-08-01

    Open Access (OA) in scholarly literature means the "immediate, free availability on the public internet, permitting any users to read, download, copy, distribute, print, search or link to the full text of these articles". The Open Access movement has been made possible thanks to the wide-spread availability of internet access and has received increasing interest since the 1990s, mostly due to the fast rising journal subscription prices. This presentation will review the current situation of Open Access in astronomy. It will answer the question why it makes sense to publish in an OA journal and will provide criteria to judge the quality of OA journals and publishers, along with suggestions how to identify so-called predatory publishers.

  16. Teaching Astronomy in UK Schools

    Science.gov (United States)

    Roche, Paul; Roberts, Sarah; Newsam, Andy; Barclay, Charles

    2012-01-01

    This article attempts to summarise the good, bad and (occasionally) ugly aspects of teaching astronomy in UK schools. It covers the most common problems reported by teachers when asked about covering the astronomy/space topics in school. Particular focus is given to the GCSE Astronomy qualification offered by Edexcel (which is currently the…

  17. School-Based Extracurricular Astronomy

    Science.gov (United States)

    Stanger, Jeffrey J.

    2010-01-01

    The International Year of Astronomy in 2009 focused considerable public attention on Astronomy and generated valuable resources for educators. These activities are an effective vehicle for promoting Science to students and to the wider school community. The most engaging practical astronomy activities are best delivered with sustained support from…

  18. Quickly Creating Interactive Astronomy Illustrations

    Science.gov (United States)

    Slater, Timothy F.

    2015-01-01

    An innate advantage for astronomy teachers is having numerous breathtaking images of the cosmos available to capture students' curiosity, imagination, and wonder. Internet-based astronomy image libraries are numerous and easy to navigate. The Astronomy Picture of the Day, the Hubble Space Telescope image archive, and the NASA Planetary…

  19. Conceptual design of advanced central receiver power systems sodium-cooled receiver concept. Volume 2, Book 1. Commercial plant conceptual design. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    The conceptual design of the 100-MW solar tower focus commercial power plant is described in detail. Sodium is pumped up to the top of a tall tower where the receiver is located. The sodium is heated in the receiver and then flows down the tower, through a pressure reducing device, and thence into a large, hot storage tank which is located at ground level and whose size is made to meet a specific thermal energy storage capacity requirement. From this tank, the sodium is pumped by a separate pump, through a system of sodium-to-water steam generators. The steam generator system consists of a separate superheater and reheater operating in parallel and an evaporator unit operating in series with the other two units. The sodium flowing from the evaporator unit is piped to a cold storage tank. From the cold storage tank, sodium is then pumped up to the tip of the tower to complete the cycle. The steam generated in the steam generators is fed to a conventional off-the-shelf, high-efficiency turbine. The steam loop operates in a conventional rankine cycle with the steam generators serving the same purpose as a conventional boiler and water being fed to the evaporator with conventional feedwater pumps. The pressure reducing device (a standard drag valve, for example) serves to mitigate the pressure caused by the static head of sodium and thus allows the large tanks to operate at ambient pressure conditions. (WHK)

  20. The handy astronomy answer book

    CERN Document Server

    Liu, PhD, Charles

    2013-01-01

    From planetary movements and the exploration of our solar system to black holes and dark matter, this comprehensive reference simplifies all aspects of astronomy with an approachable question-and-answer format. With chapters broken into various astronomical studies—including the universe, galaxies, planets, and space exploration—this fully updated resource is an ideal companion for students, teachers, and amateur astronomers, answering more than 1,00 questions, such as Is the universe infinite? What would happen to you if you fell onto a black hole? What are the basic concepts of Einstein''s s

  1. 30 CFR 75.704 - Grounding frames of stationary high-voltage equipment receiving power from ungrounded delta systems.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding frames of stationary high-voltage...-UNDERGROUND COAL MINES Grounding § 75.704 Grounding frames of stationary high-voltage equipment receiving power from ungrounded delta systems. The frames of all stationary high-voltage equipment receiving...

  2. All-optical OFDM system using a wavelength selective switch based transmitter and a spectral magnification based receiver

    DEFF Research Database (Denmark)

    Guan, Pengyu; Lefrancois, S.; Lillieholm, Mads;

    2014-01-01

    We demonstrate an AO-OFDM system with a WSS-based transmitter and time-lens based receiver for spectral magnification, achieving BER~10-9 for a 28×10 Gbit/s DPSK AO-OFDM signal. Furthermore, the receiver performance for DPSK and DQPSK is investigated using Monte Carlo simulations....

  3. Students Across Texas Celebrate Astronomy Day

    Science.gov (United States)

    Preston, S.; Wetzel, M.; Hemenway, M. K.

    2010-08-01

    Over the past three years, McDonald Observatory has offered special Astronomy Day videoconference programs to students across Texas—the second largest state in the U.S. (Only Alaska is larger). Videoconferencing allows many students and teachers access to our Observatory, which is remotely located 180 miles (290 kilometers) from any major city. McDonald Observatory partners with Connect2Texas to advertise the Astronomy Day event. Connect2Texas provides the electronic bridge between schools and the Observatory. They also provide an online evaluation for teachers to complete. In 2009 the Astronomy Day videoconference celebrated the International Year of Astronomy and the historic observations made by Galileo Galilei. During the videoconference, the classes explore the Moon or Venus by making real-time telescopic observations. Students also receive an introduction to the Observatory, an opportunity to perform an activity relating to Galileo's observations, and an interview with an astronomer. A website provides teachers pre-and post-video conference materials, instructions, and a certificate of completion that can be customized for each student. The website also lists content alignment with state science education standards.

  4. Astronomy 101 in Washington State High Schools

    Science.gov (United States)

    Lutz, Julie H.; Garner, S.; Stetter, T.; McKeever, J.; Santo Pietro, V.

    2011-01-01

    The University of Washington in the High School (UWHS) program enables high schools to offer the 5 quarter credits Astronomy 101 (Astr 101) course for college credits. The credits are transferable to most colleges and universities. The course provides an alternative to advance placement courses and programs such as Washington's Running Start whereby high school students take courses at community colleges. Astr 101 focuses on stars, galaxies and the universe, as well as background topics such as gravitation, electromagnetic radiation and telescopes. The course satisfies the UW "natural world” and "quantitative/symbolic reasoning” distribution requirements. Students must pay a fee to enroll, but the credits cost less than half what they would cost for the course if taken on one of the UW campuses. The course can be offered as either one semester or full-year at the high school. Teachers who offer Astr 101 must be approved in advance by the UW Astronomy Department, and their syllabi and course materials approved also. Teachers receive orientation, professional development opportunities, classroom visits and support (special web site, answering questions, making arrangements for campus visits, planetarium visits) from astronomy department course coordinator. The UWHS Astr 101 program has produced positive outcomes for the astronomy department, the participating teachers and the students who complete the course. In this poster we will discuss our 5 years of experience with offering Astr 101, including benefits to the students, teachers, high schools, university and department, student outcomes, course assessments and resources for offering the course.

  5. Influence of the nonlinear phase and ASE noise on DPSK balanced optical receiver in optical fiber communication system

    Institute of Scientific and Technical Information of China (English)

    李蔚; 梅君瑶; 韩庆生; 王腾

    2009-01-01

    The analytical expression of bit error probability in a balanced differential phase-shift keying(DPSK) optical receiver considering nonlinear phase noise and EDFA ASE noise is given,which is very useful to estimate the performance of DPSK balanced and unbalanced receiver in optical communication system.Through analysis,if only nonlinear phase noise is considered,both the balance and unbalanced receivers have the same performances.But if adding the ASE noise of EDFA,the balanced receiver is better.

  6. Received Signal Strength Database Interpolation by Kriging for a Wi-Fi Indoor Positioning System.

    Science.gov (United States)

    Jan, Shau-Shiun; Yeh, Shuo-Ju; Liu, Ya-Wen

    2015-08-28

    The main approach for a Wi-Fi indoor positioning system is based on the received signal strength (RSS) measurements, and the fingerprinting method is utilized to determine the user position by matching the RSS values with the pre-surveyed RSS database. To build a RSS fingerprint database is essential for an RSS based indoor positioning system, and building such a RSS fingerprint database requires lots of time and effort. As the range of the indoor environment becomes larger, labor is increased. To provide better indoor positioning services and to reduce the labor required for the establishment of the positioning system at the same time, an indoor positioning system with an appropriate spatial interpolation method is needed. In addition, the advantage of the RSS approach is that the signal strength decays as the transmission distance increases, and this signal propagation characteristic is applied to an interpolated database with the Kriging algorithm in this paper. Using the distribution of reference points (RPs) at measured points, the signal propagation model of the Wi-Fi access point (AP) in the building can be built and expressed as a function. The function, as the spatial structure of the environment, can create the RSS database quickly in different indoor environments. Thus, in this paper, a Wi-Fi indoor positioning system based on the Kriging fingerprinting method is developed. As shown in the experiment results, with a 72.2% probability, the error of the extended RSS database with Kriging is less than 3 dBm compared to the surveyed RSS database. Importantly, the positioning error of the developed Wi-Fi indoor positioning system with Kriging is reduced by 17.9% in average than that without Kriging.

  7. Bibliographic Resources for the Historian of Astronomy

    Science.gov (United States)

    Corbin, B. G.

    1999-12-01

    Many large library collections now have online bibliographic catalogs on the web. These provide many hidden resources for the historian of astronomy. Special searching techniques will allow the historian to scan bibliographic records of hundreds of entries relating to biographies of astronomers, collected works of astronomers, ancient and medieval astronomy and many other historical subjects. Abstract databases such as the Astrophysics Data System and ARIBIB are also adding much historical bibliographic information. ARIBIB will eventually contain scanned images of the Astronomischer Jahresbericht containing bibliographic entries for all literature of astronomy from 1899 to 1968 and Astronomy and Astrophysics Abstracts from 1969 to present. Commercial services such as UnCover and FirstSearch provide a means of reaching bibliographic entries for journal and book literature in the history of astronomy which were not easily located in the past. A broad overview of these collections and services will be given, and searching techniques for finding ``hidden" bibliographic data will be presented. Web page addresses will be given for all sources covered.

  8. Introducing the Virtual Astronomy Multimedia Project

    Science.gov (United States)

    Wyatt, Ryan; Christensen, L. L.; Gauthier, A.; Hurt, R.

    2008-05-01

    The goal of the Virtual Astronomy Multimedia Project (VAMP) is to promote and vastly multiply the use of astronomy multimedia resources—from images and illustrations to animations, movies, and podcasts—and enable innovative future exploitation of a wide variety of outreach media by systematically linking resource archives worldwide. High-quality astronomical images, accompanied by rich caption and background information, abound on the web and yet prove notoriously difficult to locate efficiently using existing search tools. The Virtual Astronomy Multimedia Project offers a solution via the Astronomy Visualization Metadata (AVM) standard. Due to roll out in time for IYA2009, VAMP manages the design, implementation, and dissemination of the AVM standard for the education and public outreach astronomical imagery that observatories publish. VAMP will support implementations in World Wide Telescope, Google Sky, Portal to the Universe, and 365 Days of Astronomy, as well as Uniview and DigitalSky software designed specifically for planetariums. The VAMP workshop will introduce the AVM standard and describe its features, highlighting sample image tagging processes using diverse tools—the critical first step in getting media into VAMP. Participants with laptops will have an opportunity to experiment first hand, and workshop organizers will update a web page with system requirements and software options in advance of the conference (see http://virtualastronomy.org/ASP2008/ for links to resources). The workshop will also engage participants in a discussion and review of the innovative AVM image hierarchy taxonomy, which will soon be extended to other types of media.

  9. Identification and Support of Outstanding Astronomy Students

    Science.gov (United States)

    Stoev, A. D.; Bozhurova, E. S.

    2006-08-01

    The aims, organizational plan and syllabus of a specialized Astronomy School with a subject of training students for participation in the International Astronomy Olympiad, are presented. Thematic frame includes basic educational activities during the preparation and self-preparation of the students and their participation in astronomical Olympiads. A model of identification and selection of outstanding students for astronomical Olympiads has been developed. Examples of didactic systems of problems for development of mathematical, physical and astronomical skills are shown. The programme ends with individual training for solving problems on astronomy and astrophysics. Possibilities, which the characteristic, non-standard astronomical problems give for stimulating the creative and original thinking, are specified. Basic psychological condition for development of the students' creative potential - transformation of the cognitive content in emotional one - is demonstrated. The programme of identification and support of outstanding students on astronomy is realized in collaboration with The Ministry of Education and Science, Public Astronomical Observatories and Planetaria, Institute of Astronomy - Bulgarian Academy of Sciences, and The Union of Astronomers in Bulgaria.

  10. Gravity-wave astronomy

    International Nuclear Information System (INIS)

    The theoretical basis for gravity-wave astronomy is described, along with the energy and momentum of gravitational fields. Other topics discussed include:- burst and periodic sources of gravitational waves, the cosmological stochastic background, and the detection of gravitational waves. (U.K.)

  11. Extragalactic observational astronomy

    International Nuclear Information System (INIS)

    The lectures on extragalactic observational astronomy includes the redshift controversy, normal galaxies, determination of the Hubble constant using diameters of HII regions, determination of the deceleration parameter, the luminosity--volume test as evidence for the cosmological interpretation of quasars, problems involving clusters and groups of galaxies. (U.S.)

  12. Resources for Teaching Astronomy.

    Science.gov (United States)

    Grafton, Teresa; Suggett, Martin

    1991-01-01

    Resources that are available for teachers presenting astronomy in the National Curriculum are listed. Included are societies and organizations, resource centers and places to visit, planetaria, telescopes and binoculars, planispheres, star charts, night sky diaries, equipment, audiovisual materials, computer software, books, and magazines. (KR)

  13. Teaching Astronomy Using Tracker

    Science.gov (United States)

    Belloni, Mario; Christian, Wolfgang; Brown, Douglas

    2013-01-01

    A recent paper in this journal presented a set of innovative uses of video analysis for introductory physics using Tracker. In addition, numerous other papers have described how video analysis can be a meaningful part of introductory courses. Yet despite this, there are few resources for using video analysis in introductory astronomy classes. In…

  14. Astronomy on the Walls

    Science.gov (United States)

    Santascoy, J.

    2016-01-01

    Many of us are interested in increasing youth and minority involvement in the sciences. Using art that integrates images of space exploration with ethnic astronomical mythology may increase participation in astronomy in general, while also forming a bridge to underrepresented communities. This paper describes a freely available presentation of Carlos Callejo's Discover the Secrets of the Universe Through the Library for outreach.

  15. Outlook for ultraviolet astronomy

    Science.gov (United States)

    Boehm-Vitense, E.

    1981-01-01

    A brief overview of galactic and extragalactic research is given with emphasis on the problems of temperature determination, chemical abundance determination, and the question about the energy sources for the high temperature regions. Stellar astronomy, stellar winds, and the interstellar medium are among the topics covered.

  16. Colonial American Astronomy

    Science.gov (United States)

    Yeomans, Donald K.

    2007-12-01

    While a foundation of German scientific methods enabled the rapid growth of North American Astronomy in the nineteenth century, during the seventeenth and most of the eighteenth centuries, the colonial men of science looked only to the English mother country for scientific patronage and guidance. An essay on fundamental astronomy appeared in one of the annual colonial almanacs as early as 1656, telescopic observations were made about 1660 and the first original colonial astronomical work was published by Thomas Danforth on the comet of 1664. By 1671 the Copernican ideas were so espoused at Harvard College that a physics class refused to read a Ptolemaic textbook when it was assigned to them by a senior instructor. At least in the Cambridge-Boston area, contemporary colonialist had access to the most recent scientific publications from the mother country. Observations of the great comet of 1680 by the Almanac maker, John Foster, reached Isaac Newton and were used and gratefully acknowledged in his Principia. During the seventeenth century the colonial interest in astronomy was more intense than it was for other sciences but colonists still occupied a position in the scientific backwater when compared with contemporary European scientists. Nevertheless, the science of astronomy was successfully transplanted from England to North America in the seventeenth century.

  17. Operator decision support system for integrated wastewater management including wastewater treatment plants and receiving water bodies.

    Science.gov (United States)

    Kim, Minsoo; Kim, Yejin; Kim, Hyosoo; Piao, Wenhua; Kim, Changwon

    2016-06-01

    An operator decision support system (ODSS) is proposed to support operators of wastewater treatment plants (WWTPs) in making appropriate decisions. This system accounts for water quality (WQ) variations in WWTP influent and effluent and in the receiving water body (RWB). The proposed system is comprised of two diagnosis modules, three prediction modules, and a scenario-based supporting module (SSM). In the diagnosis modules, the WQs of the influent and effluent WWTP and of the RWB are assessed via multivariate analysis. Three prediction modules based on the k-nearest neighbors (k-NN) method, activated sludge model no. 2d (ASM2d) model, and QUAL2E model are used to forecast WQs for 3 days in advance. To compare various operating alternatives, SSM is applied to test various predetermined operating conditions in terms of overall oxygen transfer coefficient (Kla), waste sludge flow rate (Qw), return sludge flow rate (Qr), and internal recycle flow rate (Qir). In the case of unacceptable total phosphorus (TP), SSM provides appropriate information for the chemical treatment. The constructed ODSS was tested using data collected from Geumho River, which was the RWB, and S WWTP in Daegu City, South Korea. The results demonstrate the capability of the proposed ODSS to provide WWTP operators with more objective qualitative and quantitative assessments of WWTP and RWB WQs. Moreover, the current study shows that ODSS, using data collected from the study area, can be used to identify operational alternatives through SSM at an integrated urban wastewater management level. PMID:26893178

  18. Antiproton beam parameters measurement by a new digital-receiver-based system

    CERN Document Server

    Angoletta, Maria Elena; Chohan, V; Findlay, A; Ludwig, M; Marqversen, O; Pedersen, F

    2001-01-01

    The Antiproton Decelerator (AD) provides the users with very low intensity beams, in the 107 particles range, hence prompting the development of an innovative measuring system, which was completed in early 2000. This system measures antiproton beam intensity for bunched and debunched beams, together with momentum spread and mean momentum for debunched beams. It uses a state-of-the-art Digital Receiver board, which processes data obtained from two ultra-low-noise, wide-band AC beam transformers. These have a combined bandwidth in the range 0.02 MHz - 30 MHz and are used to measure AC beam current modulation. For bunched beams, the intensity is obtained by measuring the amplitude of the fundamental and second RF Fourier components. On the magnetic plateaus the beam is debunched for stochastic or electron cooling and longitudinal beam properties (intensity, momentum spread and mean momentum) are measured by FFT-based spectral analysis of Schottky signals. The system provides real-time information characterising ...

  19. Rapid stress system drives chemical transfer of fear from sender to receiver.

    Directory of Open Access Journals (Sweden)

    Jasper H B de Groot

    Full Text Available Humans can register another person's fear not only with their eyes and ears, but also with their nose. Previous research has demonstrated that exposure to body odors from fearful individuals elicited implicit fear in others. The odor of fearful individuals appears to have a distinctive signature that can be produced relatively rapidly, driven by a physiological mechanism that has remained unexplored in earlier research. The apocrine sweat glands in the armpit that are responsible for chemosignal production contain receptors for adrenalin. We therefore expected that the release of adrenalin through activation of the rapid stress response system (i.e., the sympathetic-adrenal medullary system is what drives the release of fear sweat, as opposed to activation of the slower stress response system (i.e., hypothalamus-pituitary-adrenal axis. To test this assumption, sweat was sampled while eight participants prepared for a speech. Participants had higher heart rates and produced more armpit sweat in the fast stress condition, compared to baseline and the slow stress condition. Importantly, exposure to sweat from participants in the fast stress condition induced in receivers (N = 31 a simulacrum of the state of the sender, evidenced by the emergence of a fearful facial expression (facial electromyography and vigilant behavior (i.e., faster classification of emotional facial expressions.

  20. Intelligent Security IT System for Detecting Intruders Based on Received Signal Strength Indicators

    Directory of Open Access Journals (Sweden)

    Yunsick Sung

    2016-10-01

    Full Text Available Given that entropy-based IT technology has been applied in homes, office buildings and elsewhere for IT security systems, diverse kinds of intelligent services are currently provided. In particular, IT security systems have become more robust and varied. However, access control systems still depend on tags held by building entrants. Since tags can be obtained by intruders, an approach to counter the disadvantages of tags is required. For example, it is possible to track the movement of tags in intelligent buildings in order to detect intruders. Therefore, each tag owner can be judged by analyzing the movements of their tags. This paper proposes a security approach based on the received signal strength indicators (RSSIs of beacon-based tags to detect intruders. The normal RSSI patterns of moving entrants are obtained and analyzed. Intruders can be detected when abnormal RSSIs are measured in comparison to normal RSSI patterns. In the experiments, one normal and one abnormal scenario are defined for collecting the RSSIs of a Bluetooth-based beacon in order to validate the proposed method. When the RSSIs of both scenarios are compared to pre-collected RSSIs, the RSSIs of the abnormal scenario are about 61% more different compared to the RSSIs of the normal scenario. Therefore, intruders in buildings can be detected by considering RSSI differences.

  1. Operator decision support system for integrated wastewater management including wastewater treatment plants and receiving water bodies.

    Science.gov (United States)

    Kim, Minsoo; Kim, Yejin; Kim, Hyosoo; Piao, Wenhua; Kim, Changwon

    2016-06-01

    An operator decision support system (ODSS) is proposed to support operators of wastewater treatment plants (WWTPs) in making appropriate decisions. This system accounts for water quality (WQ) variations in WWTP influent and effluent and in the receiving water body (RWB). The proposed system is comprised of two diagnosis modules, three prediction modules, and a scenario-based supporting module (SSM). In the diagnosis modules, the WQs of the influent and effluent WWTP and of the RWB are assessed via multivariate analysis. Three prediction modules based on the k-nearest neighbors (k-NN) method, activated sludge model no. 2d (ASM2d) model, and QUAL2E model are used to forecast WQs for 3 days in advance. To compare various operating alternatives, SSM is applied to test various predetermined operating conditions in terms of overall oxygen transfer coefficient (Kla), waste sludge flow rate (Qw), return sludge flow rate (Qr), and internal recycle flow rate (Qir). In the case of unacceptable total phosphorus (TP), SSM provides appropriate information for the chemical treatment. The constructed ODSS was tested using data collected from Geumho River, which was the RWB, and S WWTP in Daegu City, South Korea. The results demonstrate the capability of the proposed ODSS to provide WWTP operators with more objective qualitative and quantitative assessments of WWTP and RWB WQs. Moreover, the current study shows that ODSS, using data collected from the study area, can be used to identify operational alternatives through SSM at an integrated urban wastewater management level.

  2. International Agreement Will Advance Radio Astronomy

    Science.gov (United States)

    2007-12-01

    observations to produce extremely high-resolution images, and another network (the High Sensitivity Array) that uses the same technique with large telescopes to observe particularly faint celestial objects. With this technique, NRAO telescopes work with MPIfR's Effelsberg telescope to produce images hundreds of times more detailed than those from the Hubble Space Telescope. Both institutions also are part of the international collaboration building the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and of the international planning effort to build a Square Kilometer Array. The VLBA is a system of ten antennas, each with a dish 25 meters in diameter. From Mauna Kea on the Big Island of Hawaii to St. Croix in the U.S. Virgin Islands, the VLBA spans more than 8000 kilometers. Under the new agreement, the two institutions will continue their previous observational collaborations, and in addition will share resources to improve the technical capabilities of each other's telescopes, particularly at short wavelengths, They also will collaborate in the peer-reviewed process each uses to allocate observing time, and agree to mutually maintain an "open skies" policy allowing open access to each other's telescopes on a peer-reviewed basis. The agreement notes the report of the U.S. National Science Foundation's (NSF) Senior Review committee, which called upon the NRAO to seek partners to contribute to the operation of the VLBA. The MPIfR affirms its strong interest in maintaining the VLBA's unique scientific capabilities, and its monetary contribution toward the 22 GHz upgrade of the VLBA is a solid sign of that commitment. "The VLBA provides the greatest resolving power of any instrument in astronomy, and the MPIfR's contribution to enhancing its capabilities is an important validation of the VLBA's importance to frontier astrophysics," Lo said. The joint VLBA project calls for the MPIfR to fund the receiving-system upgrades and the NRAO to perform the work. The project is

  3. Alternative Adaptive Filter Structures for Improved Radio Frequency Interference Cancellation in Radio Astronomy

    CERN Document Server

    Mitchell, D A; Sault, R J

    2010-01-01

    In radio astronomy, reference signals from auxiliary antennas that receive only the radio frequency interference (RFI) can be modified to model the RFI environment at the astronomy receivers. The RFI can then be canceled from the astronomy signal paths. However, astronomers typically only require signal statistics. If the RFI statistics are changing slowly, the cancellation can be applied to the signal correlations at a much lower rate than is required for standard adaptive filters. In this paper we describe five canceler setups; precorrelation and postcorrelation cancelers that use one or two reference signals in different ways. The theoretical residual RFI and added noise levels are examined and are demonstrated using microwave television RFI at the Australia Telescope Compact Array. The RFI is attenuated to below the system noise, a reduction of at least 20 dB. While dual-reference cancelers add more reference noise than single-reference cancelers, this noise is zero-mean and only adds to the system noise,...

  4. Strategies for Teaching Astronomy

    Science.gov (United States)

    Bennett, J.

    2000-12-01

    No matter whether you are teaching school children, undergraduates, or colleagues, a few key strategies are always useful. I will present and give examples for the following five key strategies for teaching astronomy. 1. Provide a Contextual Framework: It is much easier to learn new facts or concepts if they can be ``binned" into some kind of pre-existing mental framework. Unless your listeners are already familiar with the basic ideas of modern astronomy (such as the hierarchy of structure in the universe, the scale of the universe, and the origin of the universe), you must provide this before going into the details of how we've developed this modern picture through history. 2. Create Conditions for Conceptual Change: Many people hold misconceptions about astronomical ideas. Therefore we cannot teach them the correct ideas unless we first help them unlearn their prior misconceptions. 3. Make the Material Relevant: It's human nature to be more interested in subjects that seem relevant to our lives. Therefore we must always show students the many connections between astronomy and their personal concerns, such as emphasizing how we are ``star stuff" (in the words of Carl Sagan), how studying other planets helps us understand our own, and so on. 4. Limit Use of Jargon: The number of new terms in many introductory astronomy books is larger than the number of words taught in many first courses in foreign language. This means the books are essentially teaching astronomy in a foreign language, which is a clear recipe for failure. We must find ways to replace jargon with plain language. 5. Challenge Your Students: Don't dumb your teaching down; by and large, students will rise to meet your expectations, as long as you follow the other strategies and practice good teaching.

  5. Astronomy in Georgia - Present Status and Perspectives

    Science.gov (United States)

    Todua, M.

    2016-09-01

    Astronomy in Georgia is generally represented in Abastumani Astrophysical Observatory found in 1932. It is one of the leading scientific institutes in the country. Main fields of research are solar system bodies (including near-Earth asteroids), various aspects of solar physics, stellar astronomy (including binary stars and open clusters), extragalactic objects (AGNs), theoretical astrophysics, cosmology, atmospheric and solar-terrestrial physics. Several telescopes are operational today, as well as the instruments for atmospheric studies. In 2007 the Observatory was integrated with Ilia State University, merging scientific research and education which facilitated the growth of a new generation of researchers. There are groups of astronomers and astrophysicists in other Georgian universities and institutions as well. Georgian scientists collaborate with research centers and universities worldwide. Research groups participate in various international scientific projects. The interest in astronomy in Georgia has been growing, which increases future perspectives of its development in the country.

  6. Performance and durability of high emittance heat receiver surfaces for solar dynamic power systems

    Science.gov (United States)

    Degroh, Kim K.; Roig, David M.; Burke, Christopher A.; Shah, Dilipkumar R.

    1994-01-01

    Haynes 188, a cobalt-based superalloy, will be used to make thermal energy storage (TES) containment canisters for a 2 kW solar dynamic ground test demonstrator (SD GTD). Haynes 188 containment canisters with a high thermal emittance (epsilon) are desired for radiating heat away from local hot spots, improving the heating distribution, which will in turn improve canister service life. In addition to needing a high emittance, the surface needs to be durable in an elevated temperature, high vacuum environment for an extended time period. Thirty-five Haynes 188 samples were exposed to 14 different types of surface modification techniques for emittance and vacuum heat treatment (VHT) durability enhancement evaluation. Optical properties were obtained for the modified surfaces. Emittance enhanced samples were exposed to VHT for up to 2692 hours at 827 C and less than or equal to 10(exp -6) torr with integral thermal cycling. Optical properties were taken intermittently during exposure, and after final VHT exposure. The various surface modification treatments increased the emittance of pristine Haynes 188 from 0.11 up to 0.86. Seven different surface modification techniques were found to provide surfaces which met the SD GTD receiver VHT durability requirement. Of the 7 surface treatments, 2 were found to display excellent VHT durability: an alumina based (AB) coating and a zirconia based coating. The alumina based coating was chosen for the epsilon enhancement surface modification technique for the SD GTD receiver. Details of the performance and vacuum heat treatment durability of this coating and other Haynes 188 emittance surface modification techniques are discussed. Technology from this program will lead to successful demonstration of solar dynamic power for space applications, and has potential for application in other systems requiring high emittance surfaces.

  7. Reflections on the Radio Astronomy Explorer program of the 1960s and 70s

    Science.gov (United States)

    Kaiser, M. L.

    1990-01-01

    The Radio Astronomy Explorer (RAE) program of the late 1960s and early 1970s is, to date, the only totally dedicated radio astronomy mission to have flown. However, only some of the prelaunch goals were achieved due to the unexpectedly high levels of interference from the earth in the form of both naturally occurring and man-made noise. Some important lessons in receiver design were learned which could and should be applied to any future radio astronomy missions.

  8. Sum Rate and Power Consumption of a Circular-Layout Distributed Antenna System with MMSE Receivers

    Institute of Scientific and Technical Information of China (English)

    GAN Jiansong; LI Yunzhou; ZHOU Shidong; WANG Jing

    2008-01-01

    The distributed antenna system (DAS) is considered as a promising architecture for future wireless access. This paper describes the uplink of a power-controlled circular-layout DAS (CL-DAS) with minimum mean-square error (MMSE) receivers. Results from random matrix theory are used to show that for such a DAS, the per-user sum rate and the total transmit power both converge as the number of users and antennas goes to infinity with a constant ratio of antennas to users. The relationship between the asymptotic per-user sum rate and the asymptotic total transmit power is given for all possible values of the radius of the circle on which antennas are placed. This rate-power relationship is then used to find the optimal radius. With this op-timal radius, the CL-DAS is proved to offer a significant gain compared with a traditional co-located antenna system. Simulation results demonstrate the validity of the analysis and the superiority of the DAS.

  9. Performance Analysis of a Six-Port Receiver in a WCDMA Communication System including a Multipath Fading Channel

    OpenAIRE

    Olopade, A. O.; Helaoui, M.

    2014-01-01

    Third generation communication systems require receivers with wide bandwidth of operation to support high transmission rates and are also reconfigurable to support various communication standards with different frequency bands. An ideal software defined radio (SDR) will be the absolute answer to this requirement but it is not achievable with the current level of technology. This paper proposes the use of a six-port receiver (SPR) front-end (FE) in a WCDMA communication system. A WCDMA end-to-...

  10. Grote Reber, Radio Astronomy Pioneer, Dies

    Science.gov (United States)

    2002-12-01

    something of a minor tourist attraction, he later recalled. Using electronics he designed and built that pushed the technical capabilities of the era, Reber succeeded in detecting "cosmic static" in 1939. In 1941, Reber produced the first radio map of the sky, based on a series of systematic observations. His radio-astronomy work continued over the next several years. Though not a professional scientist, his research results were published in a number of prestigious technical journals, including Nature, the Astrophysical Journal, the Proceedings of the Institute of Radio Engineers and the Journal of Geophysical Research. Reber also received a number of honors normally reserved for scientists professionally trained in astronomy, including the American Astronomical Society's Henry Norris Russell Lectureship and the Astronomical Society of the Pacific's Bruce Medal in 1962, the National Radio Astronomy Observatory's Jansky Lectureship in 1975, and the Royal Astronomical Society's Jackson-Gwilt Medal in 1983. Reber's original dish antenna now is on display at the National Radio Astronomy Observatory's site in Green Bank, West Virginia, where Reber worked in the late 1950s. All of his scientific papers and records as well as his personal and scientific correspondence are held by the NRAO, and will be exhibited in the observatory's planned new library in Charlottesville, Virginia. Reber's amateur-radio callsign, W9GFZ, is held by the NRAO Amateur Radio Club. This callsign was used on the air for the first time since the 1930s on August 25, 2000, to mark the dedication of the Robert C. Byrd Green Bank Telescope. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  11. Hybrid technology digital correlation spectrometers for astronomy and communications

    International Nuclear Information System (INIS)

    Superconductor and semiconductor technologies can be combined using hybrid-temperature hybrid-technology (HT)2 techniques to produce very-high-performance mixed-signal systems, including digital receivers and spectrometers. The thoughtful placement of the superconductor/semiconductor interface maximizes the output performance by balancing the bandwidth and digital speed of superconductor circuitry with the complexity and high aggregate data rate of semiconductor gate arrays and/or computers. Superconducting front ends can be used with auto- and cross-correlator circuits to monitor noisy spectra or to compare spectral details with known templates. Autocorrelators and cross-correlators are used as example systems. In addition, once interesting spectral features are identified, we show a band-pass digitizer can be used to zoom in on narrower swaths of bandwidth to obtain higher-resolution data. Such a coarse/fine digital RF spectrometer may find applications as diverse as radio astronomy and wireless communications.

  12. Highlights of Astronomy, Vol. 15

    Science.gov (United States)

    Corbett, Ian

    2010-11-01

    Preface; Part I. Gruber Cosmology Prize Lecture; Part II. Invited Discourses; Part III. Joint Discussions: 1. Dark matter in early-type galaxies Léon V. E. Koopmans and Tommaso Treu; 2. Diffuse light in galaxy clusters Magda Arnaboldi and Ortwin Gerhard; 3. Neutron stars - timing in extreme environments Tomaso Belloni, Mariano Méndez and Chengmin Zhang; 4. Progress in understanding the physics of Ap and related stars Margarida Cunha; 5. Modelling the Milky Way in the age of Gaia Annie C. Robin; 6. Time and astronomy Pascale Defraigne; 7. Astrophysical outflows and associated accretion phenomena Elisabete M. de Gouveia Dal Pino and Alex C. Raga; 8. Hot interstellar matter in elliptical galaxies Dong-Woo Kim and Silvia Pellegrini; 9. Are the fundamental constants varying with time? Paolo Molaro and Elisabeth Vangioni; 10. 3D views on cool stellar atmospheres - theory meets observation K. N. Nagendra, P. Bonifacio and H. G. Ludwig; 11. New advances in helio- and astero-seismology; 12. The first galaxies - theoretical predictions and observational clues; 13. Eta Carinae in the context of the most massive stars Theodore R. Gull and Augusto Damineli; 14. The ISM of galaxies in the far-infrared and sub-millimetre; 15. Magnetic fields in diffuse media Elisabete M. de Gouveia Dal Pino and Alex Lazarian; 16. IHY global campaign - whole heliosphere interval; Part IV. Special Sessions: SpS 1. IR and sub-mm spectroscopy - a new tool for studying stellar evolution Glenn Wahlgren, Hans Käufl and Florian Kerber; SpS 2. The international year of astronomy Pedro Russo, Catherine Cesarsky and Lars Lindberg Christensen; SpS 3. Astronomy in Antarctica in 2009 Michael G. Burton; SpS 4. Astronomy education between past and future J. P. De Greve; SpS 5. Accelerating the rate of astronomical discovery Ray P. Norris; SpS 6. Planetary systems as potential sites for life Régis Courtin, Alan Boss and Michel Mayor; SpS 7. Young stars, brown dwarfs, and protoplanetary disks Jane Gregorio

  13. What's New in Astronomy for 2012?

    Science.gov (United States)

    Wilkinson, John

    2012-01-01

    There's always something new happening in the field of Astronomy. This includes the immediate environment surrounding Earth, the Solar system and the universe. This article looks at some of the recent research astronomers have been undertaking this year. Each article has reference to a web site so teachers can find out more information or ask…

  14. Publication Trends in Astronomy: The Lone Author

    CERN Document Server

    Henneken, Edwin A

    2012-01-01

    In this short communication I highlight how the number of collaborators on papers in the main astronomy journals has evolved over time. We see a trend of moving away from single-author papers. This communication is based on data in the holdings of the SAO/NASA Astrophysics Data System (ADS). The ADS is funded by NASA Grant NNX09AB39G.

  15. Radio Frequency Interference: Projects and Activities Developed for the High School Earth Science, Astronomy, and Physics Classroom

    Science.gov (United States)

    Dunn, S. K.; Brown, J.

    2003-12-01

    Radio Frequency Interference: Projects and Activities Developed for the High School Earth Science, Astronomy, and Physics Classroom Susan Dunn Tewksbury Memorial High School Jason Brown Tyngsboro High School Preethi Pratap MIT Haystack Observatory The Research Experiences for Teachers (RET) program, funded by the NSF, brings teachers into research environments to interact with scientists and translate the experience into the classroom. We will describe a RET experience at the MIT Haystack Observatory which involved using an AR3000A communications receiver and a discone antenna as the basis for an Earth Science, Astronomy, and Physics classroom unit. The projects and activities in this unit were developed to help foster student learning and understanding of radio astronomy, the electromagnetic spectrum, wave dynamics, signal propagation, meteor detection, and radio frequency interference. Additionally, this RET project utilizes the SEARFE (Students Examining Australia???s Radio Frequency Environment) software developed for use with the AR3000A communications receiver to scan and monitor frequencies across the radio bandwidth to determine areas of low and high usage in the radio spectrum. Classroom activities include Scanning Protected Radio Astronomy Bandwidths, Investigating the Radio Environment, Time Variation of Signal Strength, Signal Strength vs. Location Studies, Detecting Meteors using the AR300A Receiver, Mapping the RFI Environment of Your School, AM Radio Interference, and Signal Propagation Effects. The primary focus of the unit???s activities is to address the Massachusetts State Science Frameworks for electromagnetic radiation, waves, cosmology, and matter and energy in the Earth system and foster an understanding of how everyday communications devices may cause radio frequency interference with sensitive radio astronomy equipment. The projects and activities in the unit will be used in the classroom, amended, and the results of the classroom

  16. Compendium of Practical Astronomy. Volume 1: Instrumentation and Reduction Techniques.

    Science.gov (United States)

    Augensen, H. J.; Heintz, W. D.; Roth, Günter D.

    The Compendium of Practical Astronomy is a revised and enlarged English version of the fourth edition of G. Roth's famous handbook for stargazers. In three volumes 28 carefully edited articles, aimed especially at amateur astronomers and students and teachers of astronomy in high schools and colleges, cover the length and breadth of practical astronomy. Volume 1 contains information on modern instrumentation and reduction techniques, including spherical astronomy, error estimations, telescope mountings, astrophotography, and more. Volume 2 covers the planetary system, with contributions on artificial satellites, comets, the polar aurorae, and the effects of the atmosphere on observational data. Volume 3 is devoted to stellar objects, variable stars and binary stars in particular. An introduction to the astronomical literature and a comprehensive chapter on astronomy education and instructional aids make the Compendium a useful complement to any college library, in addition to its being essential reading for all practical astronomers.

  17. Performance Analysis of a Six-Port Receiver in a WCDMA Communication System including a Multipath Fading Channel

    Directory of Open Access Journals (Sweden)

    A. O. Olopade

    2014-01-01

    Full Text Available Third generation communication systems require receivers with wide bandwidth of operation to support high transmission rates and are also reconfigurable to support various communication standards with different frequency bands. An ideal software defined radio (SDR will be the absolute answer to this requirement but it is not achievable with the current level of technology. This paper proposes the use of a six-port receiver (SPR front-end (FE in a WCDMA communication system. A WCDMA end-to-end physical layer MATLAB demo which includes a multipath channel distortion block is used to determine the viability of the six-port based receiver. The WCDMA signal after passing through a multipath channel is received using a constructed SPR FE. The baseband signal is then calibrated and corrected in MATLAB. The six-port receiver performance is measured in terms of bit error rate (BER. The signal-to-noise ratio (SNR of the transmitted IQ data is varied and the BER profile of the communication system is plotted. The effect of the multipath fading on the receiver performance and the accuracy of the calibration algorithm are obtained by comparing two different measured BER curves for different calibration techniques to the simulated BER curve of an ideal receiver.

  18. Central receiver solar thermal power system, phase 1. Progress report for period ending December 31, 1975

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-04-01

    The program objective is the preliminary design of a 10 MWe pilot solar power plant supported by major subsystem experiments. Progress is reported on the following task elements: 10 MWe pilot plant; collector subsystem design and analysis; receiver subsystem requirements; receiver subsystem design; thermal storage subsystem; electrical power generation subsystem; and pilot plant architectural engineering and support. (WDM)

  19. Reflux heat-pipe solar receivers for dish-electric systems

    Science.gov (United States)

    Andraka, Charles E.; Diver, Richard B.

    1988-04-01

    The feasibility of competitive, modular bulk electric power from the sun may be greatly enhanced by the use of a reflux heat pipe receiver to combine a heat engine with a paraboloidal dish concentrator. This combination represents a potential improvement over previous successful demonstrations of dish-electric technology in terms of enhanced performance, lower cost, longer life, and greater flexibility in engine design. In the reflux (i.e., gravity assisted) heat pipe receiver, concentrated solar radiation causes liquid metal (sodium, potassium, or NaK) to evaporate. The vapor flows to the engine interface heat exchanger, where it condenses and releases the latent heat. The condensate is returned to the receiver absorber by gravity (refluxing), and distributed over the surface by gravity and/or capillary forces in a wick lining the receiver. It is essentially an adaptation of heat pipe technology to the peculiar requirements of concentrated solar flux, and provides many advantages over conventional heated tub receiver technology. This overview paper describes the current status and future plans for the U.S. Solar Thermal Program reflux receiver development program at Sandia National Laboratories. Current work includes conventional mesh wick receivers, sintered metal wicks, and pool boiler receivers. The relative design merits and concerns of the different approaches and technology development test plans are discussed.

  20. Message-Passing Receivers for Single Carrier Systems with Frequency-Domain Equalization

    DEFF Research Database (Denmark)

    Zhang, Chuanzong; Manchón, Carles Navarro; Wang, Zhongyong;

    2015-01-01

    with sequential passing of messages achieves the best BER performance at the expense of higher computational complexity compared to that of the GAMP receiver. The parallel BP-MF receiver has complexity similar to that of GAMP, but its low convergence rate yields poor performance, especially under high signal......-to-noise ratio conditions....

  1. Adaptive Jamming Suppression in Coherent FFH System Using Weighted Equal Gain Combining Receiver over Fading Channels with Imperfect CSI

    Directory of Open Access Journals (Sweden)

    Yishan He

    2015-01-01

    Full Text Available Fast frequency hopping (FFH is commonly used as an antijamming communication method. In this paper, we propose efficient adaptive jamming suppression schemes for binary phase shift keying (BPSK based coherent FFH system, namely, weighted equal gain combining (W-EGC with the optimum and suboptimum weighting coefficient. We analyze the bit error ratio (BER of EGC and W-EGC receivers with partial band noise jamming (PBNJ, frequency selective Rayleigh fading, and channel estimation errors. Particularly, closed-form BER expressions are presented with diversity order two. Our analysis is verified by simulations. It is shown that W-EGC receivers significantly outperform EGC. As compared to the maximum likelihood (ML receiver in conventional noncoherent frequency shift keying (FSK based FFH, coherent FFH/BPSK W-EGC receivers also show significant advantages in terms of BER. Moreover, W-EGC receivers greatly reduce the hostile jammers’ jamming efficiency.

  2. A Three-Year Program of Micro- and Nano-System Technology Development for X-Ray Astronomy

    Science.gov (United States)

    Canizares, Claude R.

    1997-01-01

    For many years the work at MIT aimed at the development of new concepts and technologies for space experiments in high-energy astrophysics, but not explicitly supported by flight programs, has been supported. This work has yielded new devices and techniques for X-ray astronomy, primarily low-noise, deep-depletion charge-coupled devices (CCDS) for spectrally-resolved X-ray imaging, and high-performance transmission gratings for high-resolution X-ray spectroscopy. Among the most significant recent achievements have been the development by G. Ricker and associates of the X-ray CCD camera flying on ASCA, and currently in development for AXAF and Astro-E, and the development by C. Canizares and associates of thick, 200 nm-period transmission gratings employing the phenomenon of phase shifting for high-resolution X-ray spectroscopy up to energies of 8- 1 0 keV that is essential for the operation of the AXAF High Energy Transmission Grating Spectrometer (HETGS). Through the current SR&T grant, the latter technology is now being extended successfully to the fabrication of 100 nm-period transmission gratings, which have twice the dispersion of the AXAF gratings. We note that, among other outcomes, the modest investments of past SR&T Grants at MIT resulted in the development of the key technologies for fully one-half of the scientific instrumentation on AXAF. In addition, NASA flight programs that have benefited from previous SR&T support at MIT include the SAS 3 X-ray Observatory, which carried the first rotation modulation collimator, the Focal Plane Crystal Spectrometer (FPCS) on the Einstein Observatory, the CCD cameras on ASCA and planned for Astro-E, the High Energy Transient Experiment (HETE), the Solar EUV Monitor on the Solar and Heliospheric Observatory (SOHO), the Medium Energy Neutral Atom imager (MENA) on the Image for Magnetopause-to-aurora Global Exploration (IMAGE) mission, and the recently-approved Two Wide-Angle Imaging Neutral-atom Spectrometers (TWINS

  3. Astronomy Olympiad: An Initiative To Promote Astronomy Education In Nepal

    Science.gov (United States)

    Bhattarai, Suresh

    2015-08-01

    This paper presents National Astronomy Olympiad Program as a new initiative towards the development of astronomy education in Nepal by Nepal Astronomical Society (NASO).Innovoative components of the olympiad programs designed by NASO to engage both scince and non-science backgound people will be discussed in detail. It will discuss the first National Astronomy Olympiad 2014 and Second National Astronomy Olympiad 2015 in details. It will also present crowd funding, its effectiveness to outreach as well as collecting funds from around the world will be presented in brief. Proposed module of astronomy olympiad to promote astronnomy in the countries without formal astronomy education in high school like Nepal,will be presented in dedail. Possible strategry to strengthen such programs in developing nations and role of IAU to promote such educational program will be explored in detail.

  4. Compressed sensing techniques for receiver based post-compensation of transmitter's nonlinear distortions in OFDM systems

    KAUST Repository

    Owodunni, Damilola S.

    2014-04-01

    In this paper, compressed sensing techniques are proposed to linearize commercial power amplifiers driven by orthogonal frequency division multiplexing signals. The nonlinear distortion is considered as a sparse phenomenon in the time-domain, and three compressed sensing based algorithms are presented to estimate and compensate for these distortions at the receiver using a few and, at times, even no frequency-domain free carriers (i.e. pilot carriers). The first technique is a conventional compressed sensing approach, while the second incorporates a priori information about the distortions to enhance the estimation. Finally, the third technique involves an iterative data-aided algorithm that does not require any pilot carriers and hence allows the system to work at maximum bandwidth efficiency. The performances of all the proposed techniques are evaluated on a commercial power amplifier and compared. The error vector magnitude and symbol error rate results show the ability of compressed sensing to compensate for the amplifier\\'s nonlinear distortions. © 2013 Elsevier B.V.

  5. Gravity field error analysis - Applications of Global Positioning System receivers and gradiometers on low orbiting platforms

    Science.gov (United States)

    Schrama, Ernst J. O.

    1991-11-01

    The concept of a Global Positioning System (GPS) receiver as a tracking facility and a gradiometer as a separate instrument on a low-orbiting platform offers a unique tool to map the earth's gravitational field with unprecedented accuracies. The former technique allows determination of the spacecraft's ephemeris at any epoch to within 3-10 cm, the latter permits the measurement of the tensor of second order derivatives of the gravity field to within 0.01 to 0.0001 Eotvos units depending on the type of gradiometer. First, a variety of error sources in gradiometry where emphasis is placed on the rotational problem pursuing as well a static as a dynamic approach is described. Next, an analytical technique is described and applied for an error analysis of gravity field parameters from gradiometer and GPS observation types. Results are discussed for various configurations proposed on Topex/Poseidon, Gravity Probe-B, and Aristoteles, indicating that GPS only solutions may be computed up to degree and order 35, 55, and 85, respectively, whereas a combined GPS/gradiometer experiment on Aristoteles may result in an acceptable solution up to degree and order 240.

  6. A cryogenic phase locking loop system for a superconducting integrated receiver

    Science.gov (United States)

    Khudchenko, A. V.; Koshelets, V. P.; Dmitriev, P. N.; Ermakov, A. B.; Yagoubov, P. A.; Pylypenko, O. M.

    2009-08-01

    The authors present a new cryogenic device, an ultrawideband cryogenic phase locking loop system (CPLL). The CPLL was developed for phase locking of a flux-flow oscillator (FFO) in a superconducting integrated receiver (SIR) but can be used for any cryogenic terahertz oscillator. The key element of the CPLL is the cryogenic phase detector (CPD), a recently proposed new superconducting element. The CPD is an innovative implementation of a superconductor-insulator-superconductor tunnel junction. All components of the CPLL reside inside a cryostat at 4.2 K, with the loop length of cables 50 cm and the total loop delay 4.5 ns. So small a delay results in a CPLL synchronization bandwidth as wide as 40 MHz and allows phase locking of more than 60% of the power emitted by the FFO, even for FFO linewidths of about 11 MHz. This percentage of phase locked power is three times that achieved with conventional room temperature PLLs. Such an improvement enables reducing the FFO phase noise and extending the SIR operation range.

  7. Practical Semantic Astronomy

    Science.gov (United States)

    Graham, Matthew; Gray, N.; Burke, D.

    2010-01-01

    Many activities in the era of data-intensive astronomy are predicated upon some transference of domain knowledge and expertise from human to machine. The semantic infrastructure required to support this is no longer a pipe dream of computer science but a set of practical engineering challenges, more concerned with deployment and performance details than AI abstractions. The application of such ideas promises to help in such areas as contextual data access, exploiting distributed annotation and heterogeneous sources, and intelligent data dissemination and discovery. In this talk, we will review the status and use of semantic technologies in astronomy, particularly to address current problems in astroinformatics, with such projects as SKUA and AstroCollation.

  8. X-ray astronomy

    International Nuclear Information System (INIS)

    This book contains the lectures, and the most important seminars held at the NATO meeting on X-Ray astronomy in Erice, July 1979. The meeting was an opportune forum to discuss the results of the first 8-months of operation of the X-ray satellite, HEAO-2 (Einstein Observatory) which was launched at the end of 1978. Besides surveying these results, the meeting covered extragalactic astronomy, including the relevant observations obtained in other portions of the electromagnetic spectrum (ultra-violet, optical, infrared and radio). The discussion on galactic X-ray sources essentially covered classical binaries, globular clusters and bursters and its significance to extragalactic sources and to high energy astrophysics was borne in mind. (orig.)

  9. Astronomy and astrology

    Science.gov (United States)

    Zarka, Philippe

    2011-06-01

    Astrology meets a large success in our societies, from the private to the political sphere as well as in the media, in spite of the demonstrated inaccuracy of its psychological as well as operational predictions. We analyse here the relations between astrology and astronomy, as well as the criticisms opposed by the latter to the former. We show that most of these criticisms are weak. Much stronger ones emerge from the analysis of the astrological practice compared to the scientific method, leading us to conclude to the non-scientificity of astrology. Then we return to the success of astrology, and from its analysis we propose a renewed (and prophylactic) rôle for astronomy in society.

  10. 3D Virtual Reality for Teaching Astronomy

    Science.gov (United States)

    Speck, Angela; Ruzhitskaya, L.; Laffey, J.; Ding, N.

    2012-01-01

    We are developing 3D virtual learning environments (VLEs) as learning materials for an undergraduate astronomy course, in which will utilize advances both in technologies available and in our understanding of the social nature of learning. These learning materials will be used to test whether such VLEs can indeed augment science learning so that it is more engaging, active, visual and effective. Our project focuses on the challenges and requirements of introductory college astronomy classes. Here we present our virtual world of the Jupiter system and how we plan to implement it to allow students to learn course material - physical laws and concepts in astronomy - while engaging them into exploration of the Jupiter's system, encouraging their imagination, curiosity, and motivation. The VLE can allow students to work individually or collaboratively. The 3D world also provides an opportunity for research in astronomy education to investigate impact of social interaction, gaming features, and use of manipulatives offered by a learning tool on students’ motivation and learning outcomes. Use of this VLE is also a valuable source for exploration of how the learners’ spatial awareness can be enhanced by working in 3D environment. We will present the Jupiter-system environment along with a preliminary study of the efficacy and usability of our Jupiter 3D VLE.

  11. Development of receiving-detecting circuit for digital radiographic systems with improved spatial resolution

    Science.gov (United States)

    Ryzhikov, Volodymir D.; Opolonin, Oleksandr D.; Galkin, Serhiy M.; Voronkin, Yevheniy F.; Lysetska, Olena K.; Kostyukevych, Serhiy A.

    2009-08-01

    Detection of X-ray radiation by digital radiographic systems (DRS) is realized using multi-element detector arrays of scintillator-photodiode (S-PD) type. Accounting for our experience in development of X-ray introscopy systems, possibilities can be found for improvement of DRS detection efficiency. Namely, a more efficient use of the dynamic range of the analog-to-digit converter by means of instrumental compensation of scatter of detector characteristics and smaller apertures of individual detection channels. However, smaller apertures lead to lower levels of useful signals, and a problem emerges of signal interference over neighboring channels, which is related to optical separation of the scintillation elements. Also, more compact arrangement of electronic components of preamplifiers is achieved. The latter problem is solved by using multi-channel (from 32 to 1024 channels) photoreceiving devices (PRD). PRD has a set of photosensitive elements formed on one crystal, as well as shift registers ensuring preliminary amplification of signals and series connection to one outlet. The work envisages creation of receiving-detecting circuit (RDC) with improved spatial resolution (ISR) with the aim of producing advanced DRS with improved characteristics: density resolution better than 0.9%, and detecting ability allowing detection of θ 0.5 mm steel wire behind 6 mm steel. The work will result in the development of RDC with ISR (800-200 microns). In combination with various ionizing radiation sources and scanning mechanisms this will allow creation of DRS for many tasks of non-destructive testing (NDT) and technical diagnostics (TD), in particular, for check-up of pipelines, objects of oil and gas industries, etc. This work was supported by the Ministry of Education and Science of Ukraine, the U.S. Civilian Research and Development Foundation (CRDF), and by the NATO Science for Peace and Security Program (Project SfP-982823).

  12. Acceptance test report, 241-SY-101 Flexible Receiver System, Phase 2 testing

    International Nuclear Information System (INIS)

    This document summarizes the results of the Phase 2 acceptance test of the 241-SY-101 Flexible Receiver System (FRS). The FRS is one of six major components of the Equipment Removal System, which has been designed to retrieve, transport, and store the test mixer pump currently installed in Tank 241-SY-101. The purpose of this acceptance test is to verify the strength of the containment bag and bag bottom cinching mechanism. It is postulated that 68 gallons of waste could be trapped inside the pump internals. The bag must be capable of supporting this waste if it shakes loose and drains to the bottom of the bag after the bag bottom has been cinched closed. This acceptance test was performed at the Maintenance and Storage Facility (MASF) Facility in the 400 area on January 23, 1995. The bag assembly supported the weight of 920 kg (2,020 lbs) of water with no leakage or damage to the bag. This value meets the acceptance criteria of 910 kg of water and therefore the results were found to be acceptable. The maximum volume of liquid expected to be held up in the pump internals is 258 L (68 gallons), which corresponds to 410 kg. This test weight gives just over a safety factor of 2. The bag also supported a small shock load while it was filled with water when the crane hoisted the bag assembly up and down. Based on the strength rating of the bag components, the bag assembly should support 2--3 times the test weight of 910 kg

  13. Next-generation Astronomy

    OpenAIRE

    Norris, Ray P

    2010-01-01

    Fundamental changes are taking place in the way we do astronomy. In twenty years time, it is likely that most astronomers will never go near a cutting-edge telescope, which will be much more efficiently operated in service mode. They will rarely analyse data, since all the leading-edge telescopes will have pipeline processors. And rather than competing to observe a particularly interesting object, astronomers will more commonly group together in large consortia to observe massive chunks of th...

  14. Effects of vertically ribbed surface roughness on the forced convective heat losses in central receiver systems

    Science.gov (United States)

    Uhlig, Ralf; Frantz, Cathy; Fritsch, Andreas

    2016-05-01

    External receiver configurations are directly exposed to ambient wind. Therefore, a precise determination of the convective losses is a key factor in the prediction and evaluation of the efficiency of the solar absorbers. Based on several studies, the forced convective losses of external receivers are modeled using correlations for a roughened cylinder in a cross-flow of air. However at high wind velocities, the thermal efficiency measured during the Solar Two experiment was considerably lower than the efficiency predicted by these correlations. A detailed review of the available literature on the convective losses of external receivers has been made. Three CFD models of different level of detail have been developed to analyze the influence of the actual shape of the receiver and tower configuration, of the receiver shape and of the absorber panels on the forced convective heat transfer coefficients. The heat transfer coefficients deduced from the correlations have been compared to the results of the CFD simulations. In a final step the influence of both modeling approaches on the thermal efficiency of an external tubular receiver has been studied in a thermal FE model of the Solar Two receiver.

  15. Teaching Astronomy Online

    Science.gov (United States)

    Maddison, Sarah T.; Mazzolini, Margaret M.

    Swinburne Astronomy Online (SAO) is a fully online graduate astronomy program with students and instructors located in over 30 countries around the globe. SAO uses a hybrid online form of delivery with image and animation-rich course content provided on CD-ROMs and the Internet used for communication research and assessment purposes. Now in its nineth semester and continuing to grow SAO can be considered a 'success story' in new teaching methods and used as an example for online education programs. One of the key distinguishing features of online education as compared to other forms of distance education is the opportunity for instructors and students to interact via online asynchronous discussion forums. Asynchronous discussion forums are used to a varying degree in different online academic programs and in widely different ways. In this paper we will give a historical overview of SAO and how it operates what astronomy we teach online and why specifically focusing on the use of asynchronous discussion forums - which are a central feature of the SAO program - as a learning and teaching tool

  16. Astronomy in the streets

    Science.gov (United States)

    Kebe, Fatoumata

    2015-08-01

    The Ephemerides Association was founded last year by a PhD student in Astronomy. The association is devoted to the promotion and advancement of knowledge of the universe through research and education.The main activities of the association are scientific meetings, the planning and realization of scientific projects, the support of the scientific activities of its members, and the dissemination of related information among members and other interested persons.The association targets the disadvantaged zones of the Paris suburbs.The main issue was how to bring astronomy in those places. In the suburbs, since most of the youth are poor, most leisure activities like cinema are out of your reach. Thus, mostly of them will play football or basketball outside.We decided to go to meet young people who find themselves together in the evening. We prepare the telescope as well as the fasicules to start the observation of the planets. The discussion finally lead to their career plans and aspirations. Astronomy has become a tool to address societal issues. We present our results after one year of activity.

  17. An Efficient Rank Adaptation Algorithm for Cellular MIMO Systems with IRC Receivers

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Berardinelli, Gilberto; Tavares, Fernando Menezes Leitão;

    2014-01-01

    Multiple transmit and receive antennas introduce additional degrees of freedom, which can be used to increase the number of spatial channels between a transmitter-receiver pair. Alternately, the additional degrees of freedom can be used to improve the interference resilience property with the help...... algorithm based on an estimate of the mean signal-to-interference-plus-noise ratio (SINR) at an IRC receiver; wherein, we use results from random matrix theory to derive the expression for the mean post-IRC SINR in the presence of interferers with unequal powers. The performance of the proposed algorithm...

  18. Episodes from the Early History of Astronomy

    Science.gov (United States)

    Aaboe, Asger

    The author does not attempt to give a general survey of early astronomy; rather, he chooses to present a few "episodes" and treats them in detail. However, first he provides the necessary astronomical background in his descriptive account of what you can see when you look at the sky with the naked eye, unblinkered by received knowledge, but with curiosity and wit. Chapter 1 deals with the arithmetical astronomy of ancient Mesopotamia where astronomy first was made an exact science. Next are treated Greek geometrical models for planetary motion, culminating in Ptolemy's equant models in his Almagest. Ptolemy does not assign them absolute size in this work, but, as is shown here, if we scale the models properly, they will yield good values, not only of the directions to the planets, but of the distances to them, as well. Thus one can immediately find the dimensions of the Copernican System from parameters in the Almagest - we have evidence that Copernicus did just that. Further, Islamic astronomers' modifications of Ptolemy's models by devices using only uniform circular motion are discussed, as are Copernicus's adoption of some of them. finally, it is made precise which bothersome problem was resolved by the heliocentric hypothesis, as it was by the Tychonic arrangement. Next, the Ptolemaic System, the first cosmological scheme to incorporate quantitative models, is described as Ptolemy himself did it in a recenlty recovered passage from his Planetary Hypotheses. Here he does assign absolute size to his models in order to fit them into the snugly nested spherical shells that made up his universe. This much maligned system was, in fact, a harmonious construct that remained the basis for how educated people thought of their world for a millennium and a half. Finally, after a brief review of the geometry of the ellipse, the author gives an elementary derivation of Kepler's equation, and shows how Kepler solved it, and further proves that a planet moves very nearly

  19. The Deep Space Network: An instrument for radio astronomy research

    Science.gov (United States)

    Renzetti, N. A.; Levy, G. S.; Kuiper, T. B. H.; Walken, P. R.; Chandlee, R. C.

    1988-01-01

    The NASA Deep Space Network operates and maintains the Earth-based two-way communications link for unmanned spacecraft exploring the solar system. It is NASA's policy to also make the Network's facilities available for radio astronomy observations. The Network's microwave communication systems and facilities are being continually upgraded. This revised document, first published in 1982, describes the Network's current radio astronomy capabilities and future capabilities that will be made available by the ongoing Network upgrade. The Bibliography, which includes published papers and articles resulting from radio astronomy observations conducted with Network facilities, has been updated to include papers to May 1987.

  20. The GBT 4mm Receiver

    Science.gov (United States)

    Frayer, David T.; White, S.; Watts, G.; Stennes, M.; Maddalena, R. J.; Simon, R.; Pospieszalski, M.; Bryerton, E.

    2013-01-01

    The new 4mm receiver (67--93 GHz) for the Robert C. Byrd Green Bank Telescope (GBT) was built to take advantage of the improved surface accuracy of the dish. The low frequency end of the 3mm atmospheric window is not available with ALMA (National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  1. Message-Passing Receiver for OFDM Systems over Highly Delay-Dispersive Channels

    DEFF Research Database (Denmark)

    Barbu, Oana-Elena; Manchón, Carles Navarro; Rom, Christian;

    2016-01-01

    severely limits its equalization and detection capabilities. As a result, the bit-error-rate performance is drastically impaired. In this paper, we propose a receiver algorithm designed to cope with the interference resulting in these channel conditions. The algorithm works with blocks of received OFDM...... symbols. It implements a variational Bayesian inference method that combines the mean-field approximation for soft channel estimation, noise estimation and equalization, and belief propagation for soft detection and decoding. To exploit the property of the channel impulse response to be sparse, i...... algorithm performs better than receivers applying traditional interference cancellation and pilot-based schemes, and approaches the performance of an ideal receiver with full channel state information and perfect interference cancellation capabilities....

  2. Forecast-Driven Enhancement of Received Signal Strength (RSS)-Based Localization Systems

    OpenAIRE

    Claudio Gallicchio; Stefano Chessa; Alessio Micheli; Paolo Barsocchi

    2013-01-01

    Real-time user localization in indoor environments is an important issue in ambient assisted living (AAL). In this context, localization based on received signal strength (RSS) has received considerable interest in the recent literature, due to its low cost and energy consumption and to its availability on all wireless communication hardware. On the other hand, the RSS-based localization is characterized by a greater error with respect to other technologies. Restricting the problem to localiz...

  3. Indigenous Astronomies and Progress in Modern Astronomy

    CERN Document Server

    Ruggles, Clive

    2010-01-01

    From an anthropological point of view, the whole concept of a "path of progress" in astronomical discovery is anathema, since it implicitly downgrades other cultural perspectives, such as the many "indigenous cosmologies" that still exist in the modern world. By doing so, one risks provoking those who hold them and-as is most obvious in places such as Hawaii where the two "world-views" come into direct contact-reating avoidable resistance to that very progress. The problem is complicated by the existence of "fringe" and "new-age" views that are increasingly confused with, and even passed off as, indigenous perceptions. In a modern world where widespread public perceptions include many that are unscientific in the broadest sense of the term, I shall argue that there are actually a range of positive benefits for progress in scientific astronomy to be derived from the mutual awareness and comprehension of "genuine" cultural world-views whose goals-in common with those of modern science-are to make sense of the c...

  4. On Orbit Receiver Performance Assessment of the Geoscience Laser Altimeter System (GLAS) on ICESAT

    Science.gov (United States)

    Sun, Xiaoli; Abshire, James B.; Spinhirne, James D.; McGarry, Jan; Jester, Peggy L.; Yi, Donghui; Palm, Stephen P.; Lancaster, Redgie S.

    2006-01-01

    The GLAS instrument on the NASA's ICESat mission has provided over a billion measurements of the Earth surface elevation and atmosphere backscattering at both 532 and 1064-nm wavelengths. The receiver performance has stayed nearly unchanged since ICESat launch in January 2003. The altimeter receiver has achieved a less than 3-cm ranging accuracy when excluding the effects of the laser beam pointing angle determination uncertainties. The receiver can also detect surface echoes through clouds of one-way transmission as low as 5%. The 532-nm atmosphere backscattering receiver can measure aerosol and clouds with cross section as low as 1e-7/m.sr with a 1 second integration time and molecular backscattering from upper atmosphere with a 60 second integration time. The 1064-nm atmosphere backscattering receiver can measure aerosol and clouds with a cross section as low as 4e-6/m.sr. This paper gives a detailed assessment of the GLAS receiver performance based on the in-orbit calibration tests.

  5. Accessible Universe: Making Astronomy Accessible to All in the Regular Elementary Classroom

    Science.gov (United States)

    Grady, C. A.; Farley, N.; Avery, F.; Zamboni, E.; Clark, B.; Geiger, N.; de Angelis, M.; Woodgate, B.

    2002-05-01

    Astronomy is one of the most publicly accessible of the sciences, with a steady stream of new discoveries, and wide public interest. The study of exo-planetary systems is a natural extension of studies of the Solar System at the elementary and middle-school level. Such space-related topics are some of the most popular science curriculum areas at the elementary level and can serve as a springboard to other sciences, mathematics, and technology for typical student learners. Not all students are typical: 10 percent of American students are identified as having disabilities which impact their education sufficiently that they receive special education services; various estimates suggest that an additional 10 percent may have milder impairments. Most frequently these students are placed in comprehensive (mixed-ability) classrooms. Budgetary limitations for most school systems have meant that for the bulk of these children, usually those with comparatively mild learning impairments affecting their ability to access text materials and in some cases to make effective use of visual materials, individualized accommodations in the science curriculum have not been readily available. Our team, consisting of an astronomer, regular education teachers, and special educators has been piloting a suite of curriculum materials, modified activities, including use of assistive technology, age- appropriate astronomy web resources, and instructional strategies which can more effectively teach astronomy to children with disabilities in the regular education grade 3-5 classroom. This study was supported by a grant HST-EO-8474 from the STScI and funded by NASA.

  6. Astronomy Education for Physics Students

    Indian Academy of Sciences (India)

    J. H. Fan; J. S. Zhang; J. Y. Zhang; Y. Liu; H. G. Wang

    2011-03-01

    Astronomy is a very interesting subject for undergraduate students studying physics. In this paper, we report astronomy education for undergraduate students in the Physics Department of Guangzhou University, and how we are teaching astronomy to the students. Astrophysics has been rapidly developing since 1994, when the center for astrophysics was founded. Now, astrophysics has become a key subject in Guangdong Province, and the Astronomy Science and Technology Research Laboratory one of the key laboratories of the Department of Education of the Guangdong Province. Many undergraduate students, working under the tutorship of faculty members completed their thesis at the Center for Astrophysics in Guangzhou.

  7. Summary: Special Session SpS15: Data Intensive Astronomy

    Science.gov (United States)

    Montmerle, Thierry

    2015-03-01

    A new paradigm in astronomical research has been emerging - ``Data Intensive Astronomy'' that utilizes large amounts of data combined with statistical data analyses. The first research method in astronomy was observations by our eyes. It is well known that the invention of telescope impacted the human view on our Universe (although it was almost limited to the solar system), and lead to Keplerfs law that was later used by Newton to derive his mechanics. Newtonian mechanics then enabled astronomers to provide the theoretical explanation to the motion of the planets. Thus astronomers obtained the second paradigm, theoretical astronomy. Astronomers succeeded to apply various laws of physics to reconcile phenomena in the Universe; e.g., nuclear fusion was found to be the energy source of a star. Theoretical astronomy has been paired with observational astronomy to better understand the background physics in observed phenomena in the Universe. Although theoretical astronomy succeeded to provide good physical explanations qualitatively, it was not easy to have quantitative agreements with observations in the Universe. Since the invention of high-performance computers, however, astronomers succeeded to have the third research method, simulations, to get better agreements with observations. Simulation astronomy developed so rapidly along with the development of computer hardware (CPUs, GPUs, memories, storage systems, networks, and others) and simulation codes.

  8. Transmission of Babylonian Astronomy to Other Cultures

    Science.gov (United States)

    Jones, Alexander

    Babylonian astronomy and astrology were extensively transmitted to other civilizations in the second and first millennia BC. Greek astronomy in particular was largely shaped by knowledge of Babylonian observations and mathematical astronomy.

  9. Virtual Learning Environment for Astronomy Education

    Science.gov (United States)

    Hoban, S.; Kumar, S.

    2004-12-01

    We have developed a virtual learning environment for astronomy education, which we call VTIE (for Virtual Telescopes in Education). While astronomy often inspires "oohs" and "ahhs" with glorious imagery, the VTIE architecture emphasizes the scientific process, eliciting questions about the nature of celestial objects and the physical processes which give rise to the pretty pictures. VTIE aims to bring observational astronomy directly to learners in both formal and informal settings by providing tools for both educators and students. For educators, VTIE provides the capability to design astronomy experiments, an online review tool to comment upon students proposals and papers, and classroom management tools (e.g. messaging service and ability to create a reading list). For students, VTIE provides an interface for developing an observing proposal (details of which are designed by the educators), access to online data services, an online observing log, and a Paper Writing Tool to complete the process by reporting their results. Details of the system and practical examples will be provided.

  10. Tactile Astronomy - a Portuguese case study

    Science.gov (United States)

    Canas, L.; Alves, F.; Correia, A.

    2012-09-01

    Although astronomy plays an important role in the most various outreach initiatives, as well as school science curricula, due to its strong visual component in knowledge acquisition, astronomy subjects are not entirely well addressed and accessed by visually impaired students and/or general public. This stresses the need of more tactile material production, still very scarce in an educational context whether formal or informal. This is a case study activity developed based on different schematic tactile images of several objects present in our solar system. These images in relief, highlight, through touch, several relevant features present in the different astronomical objects studied. The scientific knowledge is apprehended through the use of a tactile key, complemented with additional information. Through proper hands-on activities implementation and careful analysis of the outcome, the adapted images associated with an explanatory key prove to be a valuable resource in tactile astronomy domain. Here we describe the process of implementing such initiative near visually impaired students. The struggles and challenges perceived by all involved and the enrichment experience of engaging astronomy with visually impaired audiences, broadening horizons in an overall experience accessible to all.

  11. Iteration-stopping scheme of turbo receiver in turbo-MIMO systems

    Institute of Scientific and Technical Information of China (English)

    Zheng Jianping; Bai Baoming; Wang Xinmei

    2008-01-01

    The iteration-stopping scheme of turbo receiver, consisting of an inner multiple-input multiple-output (MIMO) detector and an outer turbo decoder, was studied in this paper.In the inner MIMO detector,only the reliabilities of bits in those channel slots which included unreliable information bits were updated when the outer turbo code was a systematical one.In conjunction with the trigger events for stopping the turbo decoding, an iteration-stopping scheme of turbo receiver was proposed.Simulation results show that the proposed scheme has lower complexity, but almost the same error performance compared to the scheme with predetermined maximum iterations.

  12. Astronomy across cultures the history of non-Western astronomy

    CERN Document Server

    Xiaochun, Sun

    2000-01-01

    Astronomy Across Cultures: A History of Non-Western Astronomy consists of essays dealing with the astronomical knowledge and beliefs of cultures outside the United States and Europe. In addition to articles surveying Islamic, Chinese, Native American, Aboriginal Australian, Polynesian, Egyptian and Tibetan astronomy, among others, the book includes essays on Sky Tales and Why We Tell Them and Astronomy and Prehistory, and Astronomy and Astrology. The essays address the connections between science and culture and relate astronomical practices to the cultures which produced them. Each essay is well illustrated and contains an extensive bibliography. Because the geographic range is global, the book fills a gap in both the history of science and in cultural studies. It should find a place on the bookshelves of advanced undergraduate students, graduate students, and scholars, as well as in libraries serving those groups.

  13. Dyslexia and Astronomy

    Science.gov (United States)

    Schneps, Matthew H.; Greenhill, L. J.; Rose, L. T.

    2007-12-01

    Dyslexia is a hereditary neurological disability that impairs reading. It is believed that anywhere from 5% to 20% of all people in the US may have dyslexia to a greater or lesser degree. Though dyslexia is common, it is a "silent disability" in the sense that it is not easy to tell which individuals suffer from dyslexia and which do not. There is a substantial body of evidence to suggest that people with dyslexia tend to do well in science. For example, Baruj Benacerraf, a Nobel laureate in medicine, is among those whose impairments have been documented and studied. Given that dyslexia was not diagnosed in schools prior to the late 1970's, many established science researchers may have dyslexia and be unaware of their impairment. Therefore, it would not be surprising to find that substantial numbers of scientists working in the fields of astronomy and astrophysics have dyslexia, and yet be unaware of the effects this disability has had on their research. A recently proposed theory by the authors suggests that there may be specific neurological reasons why those with dyslexia may be predisposed to science, and predicts that dyslexia may be associated with enhanced abilities for certain types of visual processing, with special implications for image processing. Our study, funded by the NSF, investigates this hypothesis in the context of astronomy and astrophysics. We expect this work will uncover and document challenges faced by scientists with dyslexia, but perhaps more importantly, lead to an understanding of the strengths these scientists bring to research. The program will serve as a clearing-house of information for scientists and students with dyslexia, and begin to provide mentoring for young people with dyslexia interested in astronomy. Scientists who have reason to believe they may have dyslexia are encouraged to contact the authors.

  14. Noise Stability of SIS Receivers

    Science.gov (United States)

    Kooi, J. W.; Chattopadhyay, G.; Thielman, M.; Phillips, T. G.; Schieder, R.

    2000-05-01

    There is a strong interest in the submillimeter astronomy community to increase the IF bandwidth of SIS receivers in order to better facilitate broad spectral linewidth and continuum observations of extragalactic sources. However, with an increase in receiver IF bandwidth there is a decrease in the mixer stability. This in turn effects the integration efficiency and quality of the measurement. In order to better understand the noise mechanisms responsible for reducing the receiver stability, we employed a technique first described by D.W. Allan and later elaborated upon by Schieder et al. In this paper we address a variety of factors that degrade the noise stability of SIS receivers. The goal of this exercise is to make recommendations aimed at maximizing SIS receiver stability.

  15. Panoramic Radio Astronomy

    OpenAIRE

    Heald, G.; P. Serra

    2009-01-01

    In this contribution we give a brief overview of the Panoramic Radio Astronomy (PRA) conference held on 2-5 June 2009 in Groningen, the Netherlands. The conference was motivated by the on-going development of a large number of new radio telescopes and instruments which, within a few years, will bring a major improvement over current facilities. Interferometers such as the EVLA, ASKAP, ATA, MeerKAT, and APERTIF will provide a combination of larger field of view and increased simultaneous bandw...

  16. Astronomy in the classroom

    Science.gov (United States)

    Moiteiro, Bárbara; Rodrigues, Berta

    2016-04-01

    The motivation of young students to science is much higher when the theoretical teaching is accompanied by practice and these are engaged in activities that involve real problems of their society and requiring a scientific basis for its discussion. Several activities such as collaboration on current scientific experiments, direct contact with scientists, participation in science competitions, visits to Science Museums, artistic and craft activities, the use of simulators and virtual laboratories, increase the degree of student satisfaction and motivate them in their learning processes. This poster shows some of Astronomy activities with students of schools Agrupamento de Escolas José Belchior Viegas within the Physics and Chemistry classes.

  17. Islamic Mathematical Astronomy

    Science.gov (United States)

    Montelle, Clemency

    A short survey on Islamic mathematical astronomy practiced during the period running from the eight century until the fifteenth is presented. Various pertinent themes, such as the translation of foreign scientific works and their impact on the tradition; the introduction, assimilation, and critique of the Ptolemaic model; and the role of observations, will be covered. In addition, the zīj, the dominant format for astronomical works, will be briefly explained as well as the legacy of the Islamic tradition of astral sciences to other cultures.

  18. Academic Training: Astronomy from Space

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 14, 15, 16, 18 March from 11.00 to 12.00 hrs - Main Auditorium, bldg. 500 Astronomy from Space by T. Courvoisier / Observatoire de Genève In the very wide field of High Energy astrophysics we will select a number of topics that range from the source of radiative energy in the deep potential well around Schwarzschild and Kerr black holes and the basics of accretion disks around compact objects to the description and (where possible) the understanding of binary systems including a compact object (neutron star or black hole), of Active Galactic Nuclei and of gamma ray bursts. The approach that is chosen aims at giving an understanding of the most important phenomenologies encountered in high energy astrophysics rather than a detailed knowledge of one specific topic. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch

  19. Novel Received Signal Strength-Based Indoor Location System: Development and Testing

    Directory of Open Access Journals (Sweden)

    Álvarez Yuri

    2010-01-01

    Full Text Available A received signal strength- (RSS-based indoor location method (ILS for person/assets location in indoor scenarios is presented in this paper. Theoretical bases of the method are the integral equations relating the electromagnetic (EM fields with their sources, establishing a cost function relating the measured field at the receivers and the unknown position of the transmitter. The aim is to improve the EM characterization of the scenario yielding in a more accurate indoor location method. Regarding network infrastructure implementation, a set of receivers are deployed through the coverage area, measuring the RSS value from a transmitter node which is attached to the asset to be located. The location method is evaluated in several indoor scenarios using portable measurement equipment. The next step has been the network hardware implementation using a wireless sensor network: for this purpose, ZigBee nodes have been selected. Finally, RSS measurements variability due to multipath effects and nonline-of-sight between transmitter and receiver nodes is mitigated using calibration and a correction based on the difference between the free space field decay law and the measured RSS.

  20. Non-parallel coevolution of sender and receiver in the acoustic communication system of treefrogs.

    Science.gov (United States)

    Schul, Johannes; Bush, Sarah L

    2002-01-01

    Advertisement calls of closely related species often differ in quantitative features such as the repetition rate of signal units. These differences are important in species recognition. Current models of signal-receiver coevolution predict two possible patterns in the evolution of the mechanism used by receivers to recognize the call: (i) classical sexual selection models (Fisher process, good genes/indirect benefits, direct benefits models) predict that close relatives use qualitatively similar signal recognition mechanisms tuned to different values of a call parameter; and (ii) receiver bias models (hidden preference, pre-existing bias models) predict that if different signal recognition mechanisms are used by sibling species, evidence of an ancestral mechanism will persist in the derived species, and evidence of a pre-existing bias will be detectable in the ancestral species. We describe qualitatively different call recognition mechanisms in sibling species of treefrogs. Whereas Hyla chrysoscelis uses pulse rate to recognize male calls, Hyla versicolor uses absolute measurements of pulse duration and interval duration. We found no evidence of either hidden preferences or pre-existing biases. The results are compared with similar data from katydids (Tettigonia sp.). In both taxa, the data are not adequately explained by current models of signal-receiver coevolution. PMID:12350274

  1. Solar central receiver hybrid power system. Monthly technical progress report for the month of December 1978

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-17

    Levelized busbar energy costs for the sodium-cooled hybrid central receiver concept using both oil and coal as a fuel were developed as a function of the plant capacity factor and as a function of the solar multiple. The fuel escalation question was reviewed in detail on the basis of past historical data, and it was concluded that the lower escalation numbers that are provided in the requirements definition document appear to be more likely to represent the real situation. Subsystem-level trade studies were continued during this reporting period. A detailed investigation of the series/parallel arrangement of the sodium heater and solar receiver was conducted. The various performance, lifetime, and cost factors were determined for each arrangement for the receiver and nonsolar subsystems, respectively. Collector subsystem studies were continued. Revised cost algorithms that include levelized O and M costs for the heliostats were generated in order that they can be used in the field optimization. On the basis of the subsystem studies and the economic assessment work, a reference configuration was tentatively derived. This configuration does not require storage and uses a parallel arrangement of the receiver and the heater. At this time, a coal-fired heater seems to have a potential economic advantage under realistic assumptions for the escalation of coal relative to oil over the next decade or so.

  2. Astronomie spatiale infrarouge, aujourd’hui et demain = Infrared space astronomy, today and tomorrow

    CERN Document Server

    Lequeux, J; David, F

    2000-01-01

    This book brings together the lectures given at the Les Houches summer school "Infrared space astronomy, today and tomorrow". It gives a wide overview of infrared astronomy, a wavelength domain crucial for studies of the solar system, stars at the beginning and end of their lives, interstellar matter and galaxies at all distances. Recent developments in observational techniques have been tremendous. The first contributions give an introduction to the basic physical processes and methods of detection and data processing. They are followed by a series of lectures dealing with the wide variety of astronomical objects that can be seen in the infrared.

  3. New astronomy with the Odin Satellite

    Science.gov (United States)

    Hjalmarson, A.

    On 20 February 2001 the Odin satellite - a new observatory for sub-millimetre wave spectroscopy - was launched from Svobodny in far-eastern Russia. The Odin project is a shared (50/50%) astronomy/aeronomy mission support ed by space agencies and scientists in Canada, Finland, France and Sweden. The satellite has been developed and is operated by the Swedish Space Corporation. The astronomy part of the mission is focussed on observations of line emission from interstellar H2O and O2. Odin houses a high-precision 1.1m diameter offset Gregorian telescope equipped with a very flexible cryogenic submm/mm receiver package. The frequency range 541-581 GHz is covered by three tuneable Schottky mixers and a fourth Schottky mixer covers the band 486-504 GHz.A 119 GHz fix-tuned HEMT preamplifier has been installed to allow very sensitive searches for interstellar O2. All receivers are operated in single-sideband mode. Any combination of four, three, or two receivers (depending upon the available power and mode of operation) can be used in combination with two auto-correlation spectrometers (bandwidth range: 100-800 MHz; resolution range: 0.125 -1 MHz) and an acousto-optical spectrometer, AOS (bandwidth: 1000 MHz; resolution 1 MHz). The Odin antenna beam-widths are about 2' and 9' at 557 and 119 GHz. For comparison, the SWAS (previous talk, by G. Melnick) antenna beam size is 3.3' x 4.5' at 557 GHz. In this talk I will focus on new Odin astronomy results where the higher angular resolution, higher frequency resolution, larger spectrometer bandwidth, higher sensitivity, or tuning capability (compared to SWAS) are important. Information on the Odin project can be found on the Odin web-page of the Swedish National Space Board (http://www.snsb.se/Odin/Odin.html).

  4. Science and Mathematics in Astronomy

    Science.gov (United States)

    Woolack, Edward

    2009-01-01

    A brief historical introduction to the development of observational astronomy will be presented. The close historical relationship between the successful application of mathematical concepts and advances in astronomy will be presented. A variety of simple physical demonstrations, hands-on group activities, and puzzles will be used to understand how the properties of light can be used to understand the contents of our universe.

  5. ``Curious About Astronomy?": Cornell University's Ask an Astronomer Website

    Science.gov (United States)

    Carruba, V.; Carter, L. M.; Cuk, M.; Jackson, M. A.; Jordan, C. E.; Krco, M.; Masters, K. L.; Pandian, J. D.; Rothstein, D. M.; Saintonge, A.; Scharringhausen, B. R.; Spekkens, K.; Springob, C. M.; Kornreich, D. A.; Curious Team

    2002-12-01

    ``Curious About Astronomy? Ask an Astronomer" is a website (http://curious.astro.cornell.edu) run by graduate and undergraduate student volunteers at Cornell University. Questions from the general public, submitted either by email or using a convenient web form, are answered by members of the Curious Team, and particularly interesting questions are posted on the website for visitors to browse. We receive and answer a few hundred questions each month from people of diverse backgrounds, including K-12 and post-secondary students and instructors, amateur astronomers, parents, scientists in various fields and others around the world with an interest in astronomy. We have recently upgraded the website, creating 22 different sections about specific topics in astronomy, a searchable index of hundreds of cross-listed questions and a page of suggestions and guidelines for teachers. The Curious Page has already become a source of useful information for the public. Questions and answers about the so-called ``Moon Hoax" and a recent news article about the Sun going supernova have received thousands of hits. By offering individual responses about any aspect of astronomy to anyone who has Internet access and by continually updating our archive of answered questions, we hope to provide a unique, growing astronomy resource for students, educators and the general public---as well as a valuable opportunity for the Curious Team to participate in educational outreach and improve its communication skills in a setting that requires no formal budget or faculty supervision.

  6. Women in Italian astronomy

    CERN Document Server

    Matteucci, Francesca

    2014-01-01

    This document gives some quantitative facts about the role of women in Italian astronomy. More than 26% of Italian IAU members are women: this is the largest fraction among the world leading countries in astronomy. Most of this high fraction is due to their presence in INAF, where women make up 32% of the research staff (289 out of 908) and 40% of the technical/administrative staff (173 out of 433); the percentage is slightly lower among permanent research staff (180 out of 599, about 30%). The presence of women is lower in the Universities (27 out of 161, about 17%, among staff). In spite of these (mildly) positive facts, we notice that similarly to other countries (e.g. USA and Germany) career prospects for Italian astronomers are clearly worse for women than for men. Within INAF, the fraction of women is about 35-40% among non-permanent position, 36% for Investigators, 17% for Associato/Primo Ricercatore, and only 13% among Ordinario/Dirigente di Ricerca. The situation is even worse at University (only 6% ...

  7. Astronomy in Antarctica

    CERN Document Server

    Burton, Michael G

    2010-01-01

    Antarctica provides a unique environment for astronomy. The cold, dry and stable air found above the high plateau, as well as the pure ice below, offers new opportunities across the photon & particle spectrum. The summits of the plateau provide the best seeing conditions, the darkest skies and the most transparent atmosphere of any earth-based observing site. Astronomical activities are now underway at four plateau sites: the Amundsen-Scott South Pole Station, Concordia Station at Dome C, Kunlun Station at Dome A and Fuji Station at Dome F, in addition to long duration ballooning from the coastal station of McMurdo. Astronomy conducted includes optical, IR, THz & sub-mm, measurements of the CMBR, solar, as well as high energy astrophysics involving measurement of cosmic rays, gamma rays and neutrinos. Antarctica is also the richest source of meteorites on our planet. An extensive range of site testing measurements have been made over the high plateau. We summarise the facets of Antarctica that are dri...

  8. Astronomy in Syria

    Science.gov (United States)

    Al-Mousli, A. T.

    2006-11-01

    Syria has been involved in the field of astronomy since 1997, when Prof. F.R. QUERCI, France, visited Syria and made a presentation on the International NORT project; (NORT: the Network of Oriental Robotic Telescope), which was a selected project of the sixth United Nations/ European Space Agency Workshop on Basic Space Science (document no. A/AC.105/657 dated 13/12/1996). NORT aims to establish a robotic telescope network on high mountain peaks around the Tropic of Cancer, from Morocco in the west to the desert of China in the east. The purposes for establishing this network are technical and educational. The General Organization of Remote Sensing (GORS) has carried out a pilot study using remote sensing techniques and has selected four sites in order to determine the best location for the astronomical observatory the within NORT programme. Following this project, GORS decided to establish an office for astronomical studies, one of the earliest works of GORS in astronomy was an initiative to establish a planetarium within the GORS campus, to accommodate approximately 120 observers. A contest to choose the best planetarium design, for the Arab World, took place at GORS.

  9. Active Astronomy Roadshow Haiti

    Science.gov (United States)

    Laycock, Silas; Oram, Kathleen; Alabre, Dayana; Douyon, Ralph; UMass Lowell Haiti Development Studies Center

    2016-01-01

    College-age Haitian students working with advisors and volunteers from UMass Lowell in 2015 developed and tested an activity-based K-8 curriculum in astronomy, space, and earth science. Our partner school is located in Les Cayes, Haiti a city where only 65% of children attend school, and only half of those will complete 6th grade. Astronomy provides an accessible and non-intimidating entry into science, and activity-based learning contrasts with the predominant traditional teaching techniques in use in Haiti, to reach and inspire a different cohort of learners. Teachers are predominantly women in Haiti, so part of the effort involves connecting them with scientists, engineers and teacher peers in the US. As a developing nation, it is vital for Haitian (as for all) children to grow up viewing women as leaders in science. Meanwhile in the US, few are aware of the reality of getting an education in a 3rd world nation (i.e. most of the world), so we also joined with teachers in Massachusetts to give US school children a peek at what daily life is like for their peers living in our vibrant but impoverished neighbor. Our Haitian partners are committed to helping their sister-schools with curriculum and educator workshops, so that the overall quality of education can rise, and not be limited to the very few schools with access to resources. We will describe the activites, motivation, and and the lessons learned from our first year of the project.

  10. Panoramic Radio Astronomy

    CERN Document Server

    Heald, G

    2009-01-01

    In this contribution we give a brief overview of the Panoramic Radio Astronomy (PRA) conference held on 2-5 June 2009 in Groningen, the Netherlands. The conference was motivated by the on-going development of a large number of new radio telescopes and instruments which, within a few years, will bring a major improvement over current facilities. Interferometers such as the EVLA, ASKAP, ATA, MeerKAT, and APERTIF will provide a combination of larger field of view and increased simultaneous bandwidth, while maintaining good collecting area and angular resolution. They will achieve a survey speed 10-50 times larger at 1-2 GHz than the current possibilities, allowing for the first time optical-like all-sky extra-galactic surveys at these frequencies. Significant progress will be made in many fields of radio astronomy. In this conference we focused on research into the evolution of galaxies over the past few Gyr. In particular, wide-field observations at 1-2 GHz will provide an unprecedented panoramic view of the ga...

  11. Astronomy books in Spanish

    Science.gov (United States)

    Fierro, Julieta

    Great cultures have created language. They have discovered its strength among other reasons for education. For a long time the Bible was one of the few books available in western culture, its influence is beyond any doubt. Many developing nations have no science books in their mother tongue. They might carry a few translations but these do not convey the local culture so it is harder for students to grasp the concepts and to build on what they know. Books, even if they are extremely simple, should be written in local languages because that will facilitate the conveying of knowledge and the creation of scientific culture. In the books examples that pertain to every day local life must be given, in particular examples that have to do with women. Women play a central role in developing nations by child bearing; if they become literate they will influence enormously the quality of their children's education, in particular their science comprehension. In Mexico a collection that includes astronomy books has recently been edited by the National Council for Culture and Arts. The books are small and light, which encourages middle-school students to carry them around and read them while traveling in public transportation, such as the subway. Every other page is a new subject, that carries illustrations, abstracts and conclusions. The astronomy books are on search for extraterrestrial life, the stars and the universe. These books are distributed nation-wide and are inexpensive. They have been written by Mexican astronomers.

  12. Classics in radio astronomy

    CERN Document Server

    Sullivan, Woodruff Turner

    1982-01-01

    Radio techniques were the nrst to lead astronomy away from the quiescent and limited Universe revealed by traditional observations at optical wave­ lengths. In the earliest days of radio astronomy, a handful of radio physicists and engineers made one startling discovery after another as they opened up the radio sky. With this collection of classic papers and the extensive intro­ ductory material, the reader can experience these exciting discoveries, as well as understand the developing techniques and follow the motivations which prompted the various lines of inquiry. For instance he or she will follow in detail the several attempts to detect radio waves from the sun at the turn of the century; the unravelling by Jansky of a "steady hiss type static"; the incredible story of Reber who built a 9 meter dish in his backyard in 1937 and then mapped the Milky Way; the vital discoveries by Hey and colleagues of radio bursts from the Sun and of a discrete source in the constellation of Cygnus; the development of re...

  13. Making Astronomy Accessible

    Science.gov (United States)

    Grice, Noreen A.

    2011-05-01

    A new semester begins, and your students enter the classroom for the first time. You notice a student sitting in a wheelchair or walking with assistance from a cane. Maybe you see a student with a guide dog or carrying a Braille computer. Another student gestures "hello” but then continues hand motions, and you realize the person is actually signing. You wonder why another student is using an electronic device to speak. Think this can't happen in your class? According to the U.S. Census, one out of every five Americans has a disability. And some disabilities, such as autism, dyslexia and arthritis, are considered "invisible” disabilities. This means you have a high probability that one of your students will have a disability. As an astronomy instructor, you have the opportunity to reach a wide variety of learners by using creative teaching strategies. I will share some suggestions on how to make astronomy and your part of the universe more accessible for everyone.

  14. The Astronomy Genealogy Project

    Science.gov (United States)

    Tenn, Joseph S.

    2014-01-01

    The Astronomy Genealogy Project, to be known as AstroGen, will list as many as possible of the world's astronomers with their academic parents (aka thesis advisors) and enable the reader to trace both academic ancestors and descendants. It will be very similar to the highly successful Mathematics Genealogy Project (MGP), available at http://genealogy.math.ndsu.nodak.edu. The MGP, which has been in operation since 1996, now contains the names of about 170,000 "mathematicians." These include many physicists and astronomers, as well as practitioners of related sciences. Mitchel Keller, the director of the MGP, has generously shared the software used in that project, and the American Astronomical Society (AAS) will host AstroGen, a project of the Historical Astronomy Division, on its website. We expect to start seeking entries soon, depending on the availability of computational assistance from the AAS IT department. We are seeking volunteers to help run the project. If you are interested, please contact me at joe.tenn@sonoma.edu.

  15. New Technology Lunar Astronomy Mission

    Science.gov (United States)

    Chen, P. C.; Oliversen, R. J.; Barry, R. K.; Romeo, R.; Pitts, R.; Ma, K. B.

    1995-12-01

    A scientifically productive Moon-based observatory can be established in the near term (3-5 years) by robotic spacecraft. Such a project is affordable even taking into account NASA's currently very tight budget. In fact the estimated cost of a lunar telescope is sufficiently low that it can be financed by private industry, foundations, or wealthy individuals. The key factor is imaginative use of new technologies and new materials. Since the Apollo era, many new areas of space technology have been developed in the US by NASA, the military, academic and industry sectors, ESA, Japan, and others. These include ultralite optics, radiation tolerant detectors, precision telescope drives incorporating high temperature superconductors, smart materials, active optics, dust and thermal control structures, subminiature spectrometers, tiny radio transmitters and receivers, small rockets, innovative fuel saving trajectories, and small precision landers. The combination of these elements makes possible a lunar observatory capable of front line astrophysical research in UV-Vis-IR imaging, spectrometry, and optical interferometry, at a per unit cost comparable to that of Small Explorer (SMEX) class missions. We describe work in progress at NASA GSFC and elsewhere, applications to other space projects, and spinoff benefits to ground-based astronomy, industry, and education.

  16. Long-range high-speed visible light communication system over 100-m outdoor transmission utilizing receiver diversity technology

    Science.gov (United States)

    Wang, Yiguang; Huang, Xingxing; Shi, Jianyang; Wang, Yuan-quan; Chi, Nan

    2016-05-01

    Visible light communication (VLC) has no doubt become a promising candidate for future wireless communications due to the increasing trends in the usage of light-emitting diodes (LEDs). In addition to indoor high-speed wireless access and positioning applications, VLC usage in outdoor scenarios, such as vehicle networks and intelligent transportation systems, are also attracting significant interest. However, the complex outdoor environment and ambient noise are the key challenges for long-range high-speed VLC outdoor applications. To improve system performance and transmission distance, we propose to use receiver diversity technology in an outdoor VLC system. Maximal ratio combining-based receiver diversity technology is utilized in two receivers to achieve the maximal signal-to-noise ratio. A 400-Mb/s VLC transmission using a phosphor-based white LED and a 1-Gb/s wavelength division multiplexing VLC transmission using a red-green-blue LED are both successfully achieved over a 100-m outdoor distance with the bit error rate below the 7% forward error correction limit of 3.8×10-3. To the best of our knowledge, this is the highest data rate at 100-m outdoor VLC transmission ever achieved. The experimental results clearly prove the benefit and feasibility of receiver diversity technology for long-range high-speed outdoor VLC systems.

  17. Conformity of the time and root characteristics received at modeling of linear systems in the environment of MATLAB

    Directory of Open Access Journals (Sweden)

    Vitaliy Borodenko

    2009-10-01

    Full Text Available The author analyses conformity of the time and root characteristics received at modeling of linear systems in the environment of MATLAB, to each other and to the standard approach. The author studies conditions of reception of false or inexact results at the analysis of regulation quality on the transition characteristic.

  18. Development of Enterprise Accounting Policy on Accounting of Receivables within Payment System with Buyers

    OpenAIRE

    Nina Tsehelnyk

    2014-01-01

    The growth in receivables is one of the reasons of low solvency of domestic agricultural companies. Therefore, the important significance in the management of financial flows in the company belongs to the accounting policy as complex of principles, methods and procedures used by the company for preparation and presentation of financial statements. Successfully selected accounting policy allows optimize the payments from customers and promotes the formation of timely and relevant information o...

  19. Astronomy Olympiads in Russia and Their Position in Astronomy Education

    Science.gov (United States)

    Eskin, B.; Tarakanov, P.; Kostina, M.

    2012-12-01

    Astronomy olympiads started to be organised in Russia more than 60 years ago (then it was still USSR). In 1994, on the basis of several regional astronomy olympiads, appeared the All-Russian Astronomy Olympiad (Vserossijskaya astronomicheskaya olimpiada) or ARAO. It has been organised under the auspices of the Ministry of Education and pupils attending higher forms have taken part in it. The main objective of ARAO is to find and support talented pupils. Leading universities of the country (Russia) have also organised their own astronomy olympiads. In this way there are Astronomy Olympiads of Saint Petersburg, Moscow and Kazan. Among them the largest is that of Saint Petersburg. The main characteristic of these olympiads is that they have also included pupils of younger forms and have prepared their own tasks. The main objective of these olympiads is to find and support future students of astronomy classes at those universities. All astronomy Olympiads have played an important role in preparing future astronomers. This work is supported by Leading Scientific Schools Grant No. NSH-3290.2010.2.

  20. The design and evaluation of transmit and receive antennas for an ionospheric communications probe system: A. Multiband Dipole Antenna

    OpenAIRE

    Perros, Sotirios Georgios

    1992-01-01

    Approved for public release; distribution is unlimited This thesis reports the design, performance evaluation and construction of a transmitting antenna for an HF communications probe system. A short range ionospheric communication link between Monterey, CA, (transmit site) and San Diego, CA, (receive site) was established to test the software and hardware of this probe system. The Multiband Dipole Antenna was selected as the more practical antenna for this link, using less real estate a...

  1. The design and evaluation transmit and receive antennas for an ionospheric communications probe system: B. Sloping-vee beams

    OpenAIRE

    Bougioukos, Georgios Theodoros

    1992-01-01

    Approved for public release; distribution is unlimited The purpose of this study was to design and evaluate the performance of a transmitting antenna for an HF communications probe system. Monterey, CA, was selected as the transmit site, and San Diego, CA, was selected as the receive site to establish an ionospheric communication link to test the equipment involved in the probe system. Lieutenant, Hellenic Navy

  2. Indian Astronomy: the missing link in Eurocentric history of Astronomy

    Science.gov (United States)

    Haque, Shirin; Sharma, Deva

    2016-06-01

    A comprehensive history of Astronomy should show in reasonable chronological order, the contributions from wherever they arise in the world, once they are reliably documented. However, the authors note that consistently, the extremely rich contributions from Ancient Indian scholars like Aryabatha and Bhramagupta are omitted in Eurocentric education and syllabi. It is speculated whether religious underpinnings could have been responsible for its suppression in the past. An appeal is made to represent the history of Astronomy in Eurocentric versions, to be inclusive of Indian Astronomy as accurately and completely as possible in science education.

  3. A fixed collector employing reversible vee-trough concentrator and a vacuum tube receiver for high temperature solar energy systems

    Science.gov (United States)

    Selcuk, M. K.

    1976-01-01

    A solar heat collection system employing non-tracking reflectors integrated with a fixed vacuum tube receiver which achieves modest year-round concentration (about 2) of the sunlight at low capital costs is discussed. The axis of the vee-trough reflector lies in a east-west direction and requires reversal of the reflector surfaces only twice a year without disturbing the receiver tubes and associated plumbing. It collects most of the diffuse flux. The vacuum tube receiver with selective absorber has no convection losses while radiation and conduction losses are minimal. Significant cost reductions are offered since the vee-trough can be fabricated from inexpensive polished or plastic reflector laminated sheet metal covering 2/3 of the collection area, and only about 1/3 of the area is covered with the more expensive vacuum tube receivers. Thermal and economic performance of the vee-trough vacuum tube system, year-round variation of the concentration factor, incident flux, useful heat per unit area at various operation temperatures and energy cost estimates are presented. The electrical energy cost is estimated to be 77 mills/kWh, and the system construction cost is estimated to be $1140/kWe.

  4. Astropy: A Community Python Package for Astronomy

    CERN Document Server

    Robitaille, Thomas P; Greenfield, Perry; Droettboom, Michael; Bray, Erik; Aldcroft, Tom; Davis, Matt; Ginsburg, Adam; Price-Whelan, Adrian M; Kerzendorf, Wolfgang E; Conley, Alexander; Crighton, Neil; Barbary, Kyle; Muna, Demitri; Ferguson, Henry; Grollier, Frédéric; Parikh, Madhura M; Nair, Prasanth H; Günther, Hans M; Deil, Christoph; Woillez, Julien; Conseil, Simon; Kramer, Roban; Turner, James E H; Singer, Leo; Fox, Ryan; Weaver, Benjamin A; Zabalza, Victor; Edwards, Zachary I; Bostroem, K Azalee; Burke, D J; Casey, Andrew R; Crawford, Steven M; Dencheva, Nadia; Ely, Justin; Jenness, Tim; Labrie, Kathleen; Lim, Pey Lian; Pierfederici, Francesco; Pontzen, Andrew; Ptak, Andy; Refsdal, Brian; Servillat, Mathieu; Streicher, Ole

    2013-01-01

    We present the first public version (v0.2) of the open-source and community-developed Python package, Astropy. This package provides core astronomy-related functionality to the community, including support for domain-specific file formats such as Flexible Image Transport System (FITS) files, Virtual Observatory (VO) tables, and common ASCII table formats, unit and physical quantity conversions, physical constants specific to astronomy, celestial coordinate and time transformations, world coordinate system (WCS) support, generalized containers for representing gridded as well as tabular data, and a framework for cosmological transformations and conversions. Significant functionality is under active development, such as a model fitting framework, VO client and server tools, and aperture and point spread function (PSF) photometry tools. The core development team is actively making additions and enhancements to the current code base, and we encourage anyone interested to participate in the development of future A...

  5. Zero-forcing beamforming with receiver antenna selection in downlink multi-antenna multi-user system*

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A study on the zero-forcing beamforming (ZFBF) scheme with antenna selection at user terminals in downlink multi-antenna multi-user systems is presented. Simulation results show that the proposed ZFBF scheme with receiver antenna selection (ZFBF-AS) achieves considerable throughput improvement over the ZFBF scheme with single receiver antenna. The results also show that, with multi-user diversity, the ZFBF-AS scheme approaches the throughput performance of the ZFBF scheme using all receiver antennas (ZFBF-WO-AS) when the base station adopts semi-orthogonal user selection (SUS) algorithm, and achieves larger throughput when the base station adopts the Round-robin scheduling algorithm. Compared with ZFBF-WO-AS, the proposed ZFBF-AS scheme can reduce the cost of user equipments and the channel state information requirement at the transmitter (CSIT) as well as the multiuser scheduling complexity at the transmitter.

  6. Central Receiver Solar Thermal Power System, Phase 1. CDRL Item 2. Pilot Plant preliminary design report. Volume III, Book 1. Collector subsystem

    Energy Technology Data Exchange (ETDEWEB)

    Hallet, Jr., R. W.; Gervais, R. L.

    1977-10-01

    The central receiver system consists of a field of heliostats, a central receiver, a thermal storage unit, an electrical power generation system, and balance of plant. This volume discusses the collector field geometry, requirements and configuration. The development of the collector system and subsystems are discussed and the selection rationale outlined. System safety and availability are covered. Finally, the plans for collector portion of the central receiver system are reviewed.

  7. Analysis of optical amplifier noise in coherent optical communication systems with optical image rejection receivers

    DEFF Research Database (Denmark)

    Jørgensen, Bo Foged; Mikkelsen, Benny; Mahon, Cathal J.

    1992-01-01

    performance. Two types of optical image rejection receivers are investigated: a novel, all-optical configuration and the conventional, microwave-based configuration. The analysis shows that local oscillator-spontaneous emission beat noise (LO-SP), signal-spontaneous emission beat noise (S-SP), and spontaneous......-spontaneous beat noise (SP-SP) can all be reduced by 3 dB, thereby doubling the dynamic range of the optical amplifier. A 2.5-dB improvement in dynamic range has been demonstrated experimentally with the all-optical image rejection configuration. The implications of the increased dynamic range thus obtained...

  8. Performance improvement of OFDM-FSO multi-user communication system with combined transmit frequency diversity and receive space diversity

    Science.gov (United States)

    Kumar, Pravindra; Srivastava, Anand

    2016-05-01

    Orthogonal frequency division multiplexed (OFDM) based free space optical (FSO) communication link gives improved performance because of narrow-band interference, improved robustness against fading and high bandwidth efficiency. It is further improved using transmit frequency diversity and space diversity at the receiver. In this paper, we propose to use OFDM architecture combined with spreading code in electrical domain, referred as code division multiplexed-orthogonal frequency division multiplexing (CDM-OFDM) which provides frequency diversity at the transmitter and using more than one receiver to get receive diversity. Analytical model of CDM-OFDM-FSO communication system with photo-detector space diversity using maximal ratio combining (MRC) is analyzed in the presence of turbulent atmosphere, multi-user-interference (MUI) and timing jitter. The error performance is computed in terms of receiver sensitivity and bit-error-rate (BER). In the analysis, Gamma-Gamma distribution is considered for atmospheric turbulence. The performance of OFDM-FSO link and CDM-OFDM-FSO link is compared. It is seen that for multiple users, CDM-OFDM-FSO link with transmit and receive diversity gives improved performance as compared to OFDM-FSO link.

  9. College Astronomy Teaching Excellence Workshops

    Science.gov (United States)

    Slater, T. F.; Bennett, M.; Greene, W. M.; Pompea, S.; Prather, E. E.

    2003-12-01

    As part of the education and public outreach efforts of the NASA JPL Navigator, SIRTF Mission and the Astronomical Society of the Pacific, astronomy educators affiliated with the Conceptual Astronomy and Physics Education Research (CAPER) Team at the University of Arizona are conducting a series of two- and three-day teaching excellence workshops for college faculty. These workshops are being held in conjunction with professional society meetings, such as the American Astronomical Society and the American Association of Physics Teachers, and through the infrastructure of the National Science Foundation's Summer Chautauqua Workshop program. This three-day, interactive teaching excellence workshop focuses on dilemmas astronomy teachers face and develop practical solutions for the troubling issues in curriculum, instruction, and assessment. After reviewing the latest research about how students learn, participants define and set measurable student learning goals and objectives for students in their astronomy courses and construct effective course syllabi reflecting the ASTRO 101 goals publicized by the AAS. To improve instruction, participants learn how to create productive learning environments by using interactive lectures, peer instruction, engaging demonstrations, collaborative groups, tutorials, computer-based laboratories, and observational projects. Participants also learn how to write more effective multiple-choice tests and implement authentic assessment strategies including portfolio assessment, performance tasks, and concept maps. Texts provided at the workshop are: (i) Learner-Centered Astronomy Teaching, Slater and Adams, Prentice Hall, 2002; (ii) Great Ideas for Teaching Astronomy, Pompea, Brooks Cole, 2000; and (iii) Lecture-Tutorials for Introductory Astronomy, Adams, Prather, & Slater, Prentice Hall, 2002.

  10. Spectrometers and Polyphase Filterbanks in Radio Astronomy

    CERN Document Server

    Price, Danny C

    2016-01-01

    This review gives an introduction to spectrometers and discusses their use within radio astronomy. While a variety of technologies are introduced, particular emphasis is given to digital systems. Three different types of digital spectrometers are discussed: autocorrelation spectrometers, Fourier transform spectrometers, and polyphase filterbank spectrometers. Given their growing ubiquity and significant advantages, polyphase filterbanks are detailed at length. The relative advantages and disadvantages of different spectrometer technologies are compared and contrasted, and implementation considerations are presented.

  11. Einführung in die Astronomie.

    Science.gov (United States)

    Winnenburg, W.

    Contents: 1. Forschungbereich Astronomie. 2. Astronomische Beobachtungstechnik. 3. Bewegungen am Sternenhimmel. 4. Dynamik im Planetensystem. 5. Aufbau des Planetensystems. 6. Die Sonne. 7. Meßbare Eigenschaften der Sterne. 8. Aufbau von Sternen. 9. Veränderliche Sterne und Sonderfälle. 10. Der interstellare Raum. 11. Ko-Evolution von Sternen und Materie. 12. Astronomische Entfernungsbestimmung. 13. Milchstraßensystem. 14. Extragalaktische Systeme. 15. Das Weltall. 16. Grenzfragen.

  12. A study of a time-of-flight system used as a directional counter in gamma-ray astronomy telescopes

    International Nuclear Information System (INIS)

    A time-of-flight system designed as a directional coincidence telescope for cosmic ray experiments has been built with a good upward-downward resolution at a counter distance as short as 40 cm. It has an effective area of 1600 cm2, and a solid angle of 0.63 Sr. The counters consist of quadratic sheets of plastic scintillator viewed directly by photomultipliers through each of the four corners without using light guides. A new compensation technique for signal propagation delays, operative in two perpendicular directions, is shown to be superior to a conventional, one-dimensional compensation. This technique does not require special circuitry. (Auth.)

  13. Inverse spiking filter based acquisition enhancement in software based global positioning system receiver

    Directory of Open Access Journals (Sweden)

    G. Arul Elango

    2015-01-01

    Full Text Available The lower visibility of the satellite in the acquisition stage of a GPS receiver under worst noisy situation leads to reacquisition of the data and thereby takes a longer time to obtain the first position fix. If the impulse noise affects the GPS signal, the conventional ways of acquiring the satellites do not guarantee to meet the minimum requirement of four satellites to find the user position. The performance of GPS receiver acquisition can be improved in the low SNR level using inverse spiking filtering technique. In the proposed method, the estimate of the desired GPS L1 signal corrupted by impulse noise (gn is obtained by the prediction error filter (hopt, which is the optimum inverse filter that reshapes the noisy signal (yn into a desired GPS signal (xn. In the proposed method, to detect the visible satellites under weak signal conditions the traditional differential coherent approach is combined with the inverse spiking filter method to increase the number of visible satellites and to avoid the reacquisition process. Montecarlo simulation is carried out to assess the performance of the proposed method for C/N0 of 20 dB-Hz and results indicate that the modified differential coherent method effectively excises the noise with 90% probability of detection. Subsequently tracking operation is also tested to confirm the acquisition performance by demodulating the navigation data successfully.

  14. Monitoring System for Atmospheric Water Vapor with a Ground-Based Multi-Band Radiometer: Meteorological Application of Radio Astronomy Technologies

    Science.gov (United States)

    Nagasaki, T.; Araki, K.; Ishimoto, H.; Kominami, K.; Tajima, O.

    2016-08-01

    High-resolution estimation of thermodynamic properties in the atmosphere can help to predict and mitigate meteorological disasters, such as local heavy rainfall and tornadic storms. For the purposes of short-term forecasting and nowcasting of severe storms, we propose a novel ground-based measurement system, which observes the intensity of atmospheric radiation in the microwave range. Our multi-band receiver system is designed to identify a rapid increase in water vapor before clouds are generated. At frequencies between 20 and 30 GHz, our system simultaneously measures water vapor as a broad absorption peak at 22 GHz as well as cloud liquid water. Another band at 50-60 GHz provides supplementary information from oxygen radiation to give vertical profiles of physical temperature. For the construction of this cold receiver system, novel technologies originally developed for observations of cosmic microwave background radiation were applied. The input atmospheric signal is amplified by a cold low-noise amplifier maintained below 10 K, while the spectrum of this amplified signal is measured using a signal analyzer under ambient conditions. The cryostat also contains a cold black body at 40 K to act as a calibration signal. This calibration signal is transported to each of the receivers via a wire grid. We can select either the atmospheric signal or the calibration signal by changing the orientation of this wire. Each receiver can be calibrated using this setup. Our system is designed to be compact (<1 m3), with low power consumption (˜ 1.5 kW). Therefore, it is easy to deploy on top of high buildings, mountains, and ship decks.

  15. Astronomy a visual guide

    CERN Document Server

    Garlick, Mark A

    2004-01-01

    Space has fascinated man and challenged scientists for centuries and astronomy is the oldest and one of the most dynamic of the sciences. Here is a book that will stimulate your curiosity and feed your imagination. Detailed and fascinating text is clearly and richly illustrated with fabulous, vibrant photographs and diagrams. This is a comprehensive guide to understanding and observing the night sky, from distant stars and galaxies to our neighbouring planets; from comets to shooting stars; from eclipses to black holes. With details of the latest space probes, a series of monthly sky maps to provide guidance for the amateur observer and the latest photos from space, this book brings the beauty and wonder of our universe into your living room and will have you reaching for the telescope!

  16. Astronomy and political theory

    Science.gov (United States)

    Campion, Nicholas

    2011-06-01

    This paper will argue that astronomical models have long been applied to political theory, from the use of the Sun as a symbol of the emperor in Rome to the application of Copernican theory to the needs of absolute monarchy. We will begin with consideration of astral divination (the use of astronomy to ascertain divine intentions) in the ancient Near East. Particular attention will be paid to the use of Newton's discovery that the universe operates according to a single set of laws in order to support concepts of political quality and eighteenth century Natural Rights theory. We will conclude with consideration of arguments that the discovery of the expanding, multi-galaxy universe, stimulated political uncertainty in the 1930s, and that photographs of the Earth from Apollo spacecraft encouraged concepts of the `global village'.

  17. Gravitational wave astronomy

    CERN Document Server

    CERN. Geneva

    2016-01-01

    In the past year, the LIGO-Virgo Collaboration announced the first secure detection of gravitational waves. This discovery heralds the beginning of gravitational wave astronomy: the use of gravitational waves as a tool for studying the dense and dynamical universe. In this talk, I will describe the full spectrum of gravitational waves, from Hubble-scale modes, through waves with periods of years, hours and milliseconds. I will describe the different techniques one uses to measure the waves in these bands, current and planned facilities for implementing these techniques, and the broad range of sources which produce the radiation. I will discuss what we might expect to learn as more events and sources are measured, and as this field matures into a standard part of the astronomical milieu.

  18. Compressed Sensing in Astronomy

    CERN Document Server

    Bobin, J; Ottensamer, R

    2008-01-01

    Recent advances in signal processing have focused on the use of sparse representations in various applications. A new field of interest based on sparsity has recently emerged: compressed sensing. This theory is a new sampling framework that provides an alternative to the well-known Shannon sampling theory. In this paper we investigate how compressed sensing (CS) can provide new insights into astronomical data compression and more generally how it paves the way for new conceptions in astronomical remote sensing. We first give a brief overview of the compressed sensing theory which provides very simple coding process with low computational cost, thus favoring its use for real-time applications often found on board space mission. We introduce a practical and effective recovery algorithm for decoding compressed data. In astronomy, physical prior information is often crucial for devising effective signal processing methods. We particularly point out that a CS-based compression scheme is flexible enough to account ...

  19. Astronomy Enrollments and Degrees: Results from the 2012 Survey of Astronomy Enrollments and Degrees. Focus On

    Science.gov (United States)

    Mulvey, Patrick; Nicholson, Starr

    2014-01-01

    Interest in astronomy degrees in the U.S. remains strong, with astronomy enrollments at or near all-time highs for the 2012-13 academic year. The total number of students taking an introductory astronomy course at a degree-granting physics or astronomy department is approaching 200,000. Enrollments in introductory astronomy courses have been…

  20. Applied Historical Astronomy

    Science.gov (United States)

    Stephenson, F. Richard

    2014-01-01

    F. Richard Stephenson has spent most of his research career -- spanning more than 45 years -- studying various aspects of Applied Historical Astronomy. The aim of this interdisciplinary subject is the application of historical astronomical records to the investigation of problems in modern astronomy and geophysics. Stephenson has almost exclusively concentrated on pre-telescopic records, especially those preserved from ancient and medieval times -- the earliest reliable observations dating from around 700 BC. The records which have mainly interested him are of eclipses (both solar and lunar), supernovae, sunspots and aurorae, and Halley's Comet. The main sources of early astronomical data are fourfold: records from ancient and medieval East Asia (China, together with Korea and Japan); ancient Babylon; ancient and medieval Europe; and the medieval Arab world. A feature of Stephenson's research is the direct consultation of early astronomical texts in their original language -- either working unaided or with the help of colleagues. He has also developed a variety of techniques to help interpret the various observations. Most pre-telescopic observations are very crude by present-day standards. In addition, early motives for skywatching were more often astrological rather than scientific. Despite these drawbacks, ancient and medieval astronomical records have two remarkable advantages over modern data. Firstly, they can enable the investigation of long-term trends (e.g. in the terrestrial rate of rotation), which in the relatively short period covered by telescopic observations are obscured by short-term fluctuations. Secondly, over the lengthy time-scale which they cover, significant numbers of very rare events (such as Galactic supernovae) were reported, which have few -- if any-- counterparts in the telescopic record. In his various researches, Stephenson has mainly focused his attention on two specific topics. These are: (i) long-term changes in the Earth's rate of

  1. Diversity and Multiplexing Tradeoff in the Uplink of Cellular Systems with Linear MMSE Receiver

    CERN Document Server

    Song, Xiaoshi; Liu, Danpu

    2011-01-01

    In this paper, we extend the diversity and multiplexing tradeoff (DMT) analysis from point-to-point channels to cellular systems to evaluate the impact of inter-cell interference on the system reliability and efficiency. Fundamental tradeoff among diversity order, multiplexing gain and inter-cell interference intensity is characterized to reveal the capability of multiple antennas in cellular systems. And the detrimental effects of the inter-cell interference on the system performance of diversity and multiplexing is presented and analyzed.

  2. Astronomy at the frontiers of science

    CERN Document Server

    2011-01-01

    Astronomy is by nature an interdisciplinary activity: it involves mathematics, physics, chemistry and biology. Astronomers use (and often develop) the latest technology, the fastest computers and the most refined software.  In this book twenty-two leading scientists from nine countries talk about how astronomy interacts with these other sciences. They describe modern instruments used in astronomy and the relations between astronomy and technology, industry, politics and philosophy. They also discuss what it means to be an astronomer, the history of astronomy, and the place of astronomy in society today.   The book contains twenty chapters grouped in four parts: ASTRONOMY AND PHYSICS discusses the place of astronomy among various branches of (mostly high-energy) physics. ASTRONOMY IN SOCIETY describes not only the historical context of astronomy, but issues facing astronomers today, including funding, planning, worldwide collaboration and links with industry. THE TOOLS OF OBSERVATION AND THE PROFESSION OF AS...

  3. A high temperature superconductor tape RF receiver coil for a low field magnetic resonance imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, M C; Yan, B P; Lee, K H; Ma, Q Y; Yang, E S [Jockey Club MRI Centre, University of Hong Kong, Hong Kong (China)

    2005-08-01

    High temperature superconductor (HTS) thin films have been applied in making a low loss RF receiver coil for improving magnetic resonance imaging image quality. However, the application of these coils is severely limited by their limited field of view (FOV). Stringent fabrication environment requirements and high cost are further limitations. In this paper, we propose a simpler method for designing and fabricating HTS coils. Using industrial silver alloy sheathed Bi{sub (2-x)}Pb{sub x}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Bi-2223) HTS tapes, a five-inch single-turn HTS solenoid coil has been developed, and human wrist images have been acquired with this coil. The HTS tape coil has demonstrated an enhanced FOV over a six-inch YBCO thin film surface coil at 77 K with comparable signal-to-noise ratio.

  4. Local Oscillator Sub-Systems for Array Receivers in the 1-3 THz Range

    Science.gov (United States)

    Mehdi, Imran; Siles, Jose V.; Maestrini, Alain; Lin, Robert; Lee, Choonsup; Schlecht, Erich; Chattopadhyay, Goutam

    2012-01-01

    Recent results from the Heterodyne Instrument for the Far-Infrared (HIFI) on the Herschel Space Telescope have confirmed the usefulness of high resolution spectroscopic data for a better understanding of our Universe. This paper will explore the current status of tunable local oscillator sources with emphasis on building a multi-pixel LO subsystem for the scientifically important CII line around 1908 GHz. Recent results have shown that over 50 microwatts of output power at 1.9 THz are possible with an optimized single pixel LO chain. These power levels are now sufficient to pump array receivers in this frequency range. Further power enhancement can be obtained by cooling the chain to 120 K or by utilizing in-phase power combining technology.

  5. SWUIS-A: A Versatile, Low-Cost UV/VIS/IR Imaging System for Airborne Astronomy and Aeronomy Research

    Science.gov (United States)

    Durda, Daniel D.; Stern, S. Alan; Tomlinson, William; Slater, David C.; Vilas, Faith

    2001-01-01

    We have developed and successfully flight-tested on 14 different airborne missions the hardware and techniques for routinely conducting valuable astronomical and aeronomical observations from high-performance, two-seater military-type aircraft. The SWUIS-A (Southwest Universal Imaging System - Airborne) system consists of an image-intensified CCD camera with broad band response from the near-UV to the near IR, high-quality foreoptics, a miniaturized video recorder, an aircraft-to-camera power and telemetry interface with associated camera controls, and associated cables, filters, and other minor equipment. SWUIS-A's suite of high-quality foreoptics gives it selectable, variable focal length/variable field-of-view capabilities. The SWUIS-A camera frames at 60 Hz video rates, which is a key requirement for both jitter compensation and high time resolution (useful for occultation, lightning, and auroral studies). Broadband SWUIS-A image coadds can exceed a limiting magnitude of V = 10.5 in <1 sec with dark sky conditions. A valuable attribute of SWUIS-A airborne observations is the fact that the astronomer flies with the instrument, thereby providing Space Shuttle-like "payload specialist" capability to "close-the-loop" in real-time on the research done on each research mission. Key advantages of the small, high-performance aircraft on which we can fly SWUIS-A include significant cost savings over larger, more conventional airborne platforms, worldwide basing obviating the need for expensive, campaign-style movement of specialized large aircraft and their logistics support teams, and ultimately faster reaction times to transient events. Compared to ground-based instruments, airborne research platforms offer superior atmospheric transmission, the mobility to reach remote and often-times otherwise unreachable locations over the Earth, and virtually-guaranteed good weather for observing the sky. Compared to space-based instruments, airborne platforms typically offer

  6. Critical Issues in the Philosophy of Astronomy and Cosmology

    Science.gov (United States)

    Dick, Steven J.

    2016-01-01

    Although the philosophy of science and of specific sciences such as physics, chemistry, and biology are well-developed fields with their own books and journals, the philosophy of astronomy and cosmology have received little systematic attention. At least six categories of problems may be identified in the astronomical context: 1) the nature of reasoning, including the roles of observation, theory, simulation, and analogy, as well as the limits of reasoning, starkly evident in the anthropic principle, fine-tuning, and multiverse controversies; 2) the often problematic nature of evidence and inference, especially since the objects of astronomical interest are for the most part beyond experiment and experience;3) the influence of metaphysical preconceptions and non-scientific worldviews on astronomy, evidenced, for example in the work of Arthur S. Eddington and many other astronomers; 4) the epistemological status of astronomy and its central concepts, including the process of discovery, the problems of classification, and the pitfalls of definition (as in planets); 5) the role of technology in shaping the discipline of astronomy and our view of the universe; and 6) the mutual interactions of astronomy and cosmology with society over time. Discussion of these issues should draw heavily on the history of astronomy as well as current research, and may reveal an evolution in approaches, techniques, and goals, perhaps with policy relevance. This endeavor should also utilize and synergize approaches and results from philosophy of science and of related sciences such as physics (e.g. discussions on the nature of space and time). Philosophers, historians and scientists should join this new endeavor. A Journal of the Philosophy of Astronomy and Cosmology (JPAC) could help focus attention on their studies.

  7. Preservice elementary teachers learning of astronomy

    Science.gov (United States)

    Fidler, Chuck Gary

    The dissertation presents a new approach for the study of preservice elementary teacher astronomy education. The approach suggests that learning astronomical concepts are facilitated by greater sophistication in scale perception and spatial-aptitude. This dissertation is underscored by the national call for elementary science education reform efforts and suggests certain strategies shown more effective for the development of accurate astronomical comprehension. The present research study describes how preservice elementary teachers conceptualize and communicate ideas about Space. Instead of assuming a universal mental conception of cosmic orientations and relationships, the dissertation claims that the perception of Space related dimensions vary among preservice elementary teachers. Furthermore, the dissertation suggests individual perceptions of the scale sizes and orientations of celestial systems have direct influences on mental models used to organize and communicate astronomical information. The development of inaccurate mental models of the scaled dimensions of Space may perpetuate the teacher-student cycle of misconception and naive-theory generation among children in elementary education settings. The ability to conceptualize the vast cosmos is facilitated by the minds ability to think about vast scales and orientations of celestial objects. The Earth-based perspective of astronomy education compels the learner to think about astronomical principles within imaginary frames of reference and across unfamiliar scaled dimensions. Therefore, mental astronomical model building is underscored by the perception of scale and cosmic spatiality. This study suggests these cognitive skill sets are interconnected and facilitate the learning of accurate astronomy principles; as well as play an important role when designing an astronomy education program for preservice elementary teachers. This research study is comprised of three separate standalone articles designed and

  8. Combined cycle solar central receiver hybrid power system study. Volume III. Appendices. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-11-01

    A design study for a 100 MW gas turbine/steam turbine combined cycle solar/fossil-fuel hybrid power plant is presented. This volume contains the appendices: (a) preconceptual design data; (b) market potential analysis methodology; (c) parametric analysis methodology; (d) EPGS systems description; (e) commercial-scale solar hybrid power system assessment; and (f) conceptual design data lists. (WHK)

  9. Abundance and fate of antibiotics and hormones in a vegetative treatment system receiving cattle feedlot runoff

    Science.gov (United States)

    Vegetative treatment systems (VTS) have been developed and built as an alternative to conventional holding pond systems for managing run-off from animal feeding operations. Initially developed to manage runoff nutrients via uptake by grasses, their effectiveness at removing other runoff contaminant...

  10. Essays on medieval computational astronomy

    CERN Document Server

    Bergón, José Chabás

    2014-01-01

    In Essays on Medieval Computational Astronomy the authors provide examples of original and intelligent approaches and solutions given by medieval astronomers to the problems of their discipline, mostly presented in the form of astronomical tables.

  11. Women in Astronomy Workshop Report

    CERN Document Server

    Brough, Sarah; Brooks, Kate; Hopkins, Andrew; Maddison, Sarah

    2011-01-01

    Here we report on the Women in Astronomy Workshop (http://asawomeninastronomy.org/meetings/wia2011/), which was held on 13 May 2011 in Sydney, Australia. The workshop was organised by the Astronomical Society of Australia's Chapter on Women in Astronomy, to discuss some of the issues that face women in astronomy and make recommendations to help support the success of women in Australian astronomy but came to broader conclusions that have value for the whole astronomical community. The workshop consisted of four sessions, with presentations by invited speakers on demographics, leadership, varied career paths, and how institutions & individuals can help. The workshop ended with a discussion panel that summarised the day's debate and presented a list of recommendations for the Australian astronomical community (both individuals and institutions) that are provided in this report.

  12. Intelligent Cognitive Radio Models for Enhancing Future Radio Astronomy Observations

    Directory of Open Access Journals (Sweden)

    Ayodele Abiola Periola

    2016-01-01

    Full Text Available Radio astronomy organisations desire to optimise the terrestrial radio astronomy observations by mitigating against interference and enhancing angular resolution. Ground telescopes (GTs experience interference from intersatellite links (ISLs. Astronomy source radio signals received by GTs are analysed at the high performance computing (HPC infrastructure. Furthermore, observation limitation conditions prevent GTs from conducting radio astronomy observations all the time, thereby causing low HPC utilisation. This paper proposes mechanisms that protect GTs from ISL interference without permanent prevention of ISL data transmission and enhance angular resolution. The ISL transmits data by taking advantage of similarities in the sequence of observed astronomy sources to increase ISL connection duration. In addition, the paper proposes a mechanism that enhances angular resolution by using reconfigurable earth stations. Furthermore, the paper presents the opportunistic computing scheme (OCS to enhance HPC utilisation. OCS enables the underutilised HPC to be used to train learning algorithms of a cognitive base station. The performances of the three mechanisms are evaluated. Simulations show that the proposed mechanisms protect GTs from ISL interference, enhance angular resolution, and improve HPC utilisation.

  13. Cross-polarization in quasi-optical receivers: ALMA band 4 and 10

    Science.gov (United States)

    Gonzalez, A.; Uzawa, Y.

    2012-09-01

    A careful study about the influence of individual optical components on receiver cross-polarization has been performed. The basic mechanisms of generation of cross-polarization in ellipsoidal mirrors and dielectrics have been reviewed and characterized in terms of higher-order Gaussian beam modes. A simple model considering the phase differences of different Gaussian beam modes is proposed in order to calculate the final system cross-polarization pattern. This model has been successfully used to characterize the total cross-polarization in two cryogenically-cooled receivers for astronomy: ALMA band 4 and band 10.

  14. Encyclopedia of the History of Astronomy and Astrophysics

    Science.gov (United States)

    Leverington, David

    2013-06-01

    Preface; Part I. General Astronomy: 1. Ancient (pre-telescopy) astronomy; 2. Period overviews; 3. International Astronomical Union; Part II. The Solar System: 4. Overview - the Solar System; 5. Sun, Earth, and Moon; 6. Inner Solar System; 7. Giant planets; 8. Smaller objects; 9. Exoplanets; Part III. Stars: 10. Stars considered individually; 11. Stars considered as a group; 12. Types of stars; Part IV. Galaxies and Cosmology: 13. Milky Way; 14. Other galaxies and cosmology; Part V. General Astronomical Tools and Techniques (After 1600); Part VI. Optical Telescopes and Observatories: 15. Overview - optical telescopes and observatories; 16. Optical observatories; Part VII. Radio Telescopes, Observatories and Radar: 17. Overview - radio telescopes and observatories; 18. Early radio astronomy and observatories; 19. Later radio observatories; Part VIII. Other Ground-Based Observatories; Part IX. Solar System Exploration Spacecraft: 20. Overview - Solar System exploration spacecraft; 21. Individual Solar System spacecraft; Part X. Selected Observatory Spacecraft: 22. Overview - spacecraft observatories; 23. Individual spacecraft observatories; Name index; Subject index.

  15. The Music and the Astronomy

    CERN Document Server

    Caballero, J A; Caballero, I

    2008-01-01

    What do Brian May (the Queen's lead guitarist), William Herschel and the Jupiter Symphony have in common? And a white dwarf, a piano and Lagartija Nick? At first glance, there is no connection between them, nor between the Music and the Astronomy. However, there are many revealing examples of musical Astronomy and astronomical Music. This four-page proceeding describes the sonorous poster that we showed during the VIII Scientific Meeting of the Spanish Astronomical Society.

  16. News clippings for introductory astronomy

    Science.gov (United States)

    Bobrowsky, Matthew

    1999-09-01

    Most students entering our introductory astronomy course for nonscience majors arrive not merely lacking scientific facts-they also have misconceptions about the nature of science, and many have a handicapping ``science anxiety'' (in addition to math anxiety). So I have added a ``current science'' requirement to our introductory course. Each student must compile a file of five astronomy news articles taken from readily available sources.

  17. Correlation of scintillation occurrence with interplanetary magnetic field reversals and impact on Global Navigation Satellite System receiver tracking performance

    Science.gov (United States)

    Aquino, M.; Sreeja, V.

    2013-05-01

    Ionospheric scintillation is characterized by rapid fluctuations in the amplitude and phase of transionospheric radio signals as they pass through small scale ionospheric plasma density irregularities. Over the auroral regions, the occurrence of scintillation is associated with large-scale plasma structures and is mainly enhanced during geomagnetic storms. Scintillation can cause cycle slips and degrade the positioning accuracy in Global Navigation Satellite System (GNSS) receivers. This paper investigates the correlation between the southward reversals of the interplanetary magnetic field (IMF) Bz and the occurrence of scintillation, along with the consequential impact on the tracking performance of a GNSS receiver located at a high-latitude station, Bronnoysund (geographic latitude 65°N) in Norway. The analysis revealed that the occurrence of scintillation at this station is largely controlled by the IMF conditions. The receiver tracking performance under strong scintillations is evaluated by the receiver PLL (phase-locked loop) tracking jitter variance. The dependence of the PLL jitter variance on phase scintillation can be best represented by a quadratic fit.

  18. Music and Astronomy Under the Stars - 2009 Update

    Science.gov (United States)

    Lubowich, Donald A.

    2010-01-01

    Bring telescope to where the people are! Music and Astronomy Under the Stars is a three-year NASA-funded outreach program at parks during and after concerts and family events - a Halloween Spooky Garden Walk. While there have been many outreach activities and telescope observations at city sidewalks and parks, this program targets a completely different audience - music lovers who attend summer concerts held in community parks. These music lovers who may never have visited a science museum, planetarium, or star party are exposed to telescope observations and astronomy information with no additional travel costs. Music and Astronomy Under the Stars increased awareness, engagement, and interest in astronomy at classical, pop, rock, and ethnic music concerts. This program includes solar observing before the concerts, telescope observations including a live image projection system, an astronomical video presentation, and astronomy banners/posters. Approximately 500 - 16,000 people attended each event and 25% to 50% of the people at each event participated in the astronomy program. This program also reached underrepresented and underserved groups (women, minorities, older adults). The target audience is 2,900,000 people, which is larger than combined population of Atlanta, Boston, Denver, Minneapolis, and San Francisco. Although eleven events were planned in 2009, two were canceled due to rain and our largest event, the NY Philharmonic in the Park (attended by 67,000 people in 2008), was cancelled for financial reasons. Our largest event in 2009 was the Tanglewood Music Festival, Lenox MA, attended by 16,000 people where 5000 people participated in astronomy activities. The Amateur Observers' Society of NY assisted with the NY concerts and the Springfield STARS club assisted at Tanglewood. 1500 people looked through telescopes at the Halloween program (6000 saw the posters). In 2009 over 15,000 people participated in these astronomy activities which were attended by

  19. Astronomy at the Market

    Science.gov (United States)

    Roten, Robert; Constantin, A.; Christensen, E.; Dick, E.; Lapolla, J.; Nutter, A.; Corcoran, J.; DiDomenico, N.; Eskridge, B.; Saikin, A.

    2014-01-01

    We present here an energetic grass-roots outreach program run entirely by undergraduate physics and astronomy majors at James Madison University. Our "Team Awestronomy" takes Astronomy out to the Market, literally. Once a month, for eight months during the academic year, the group sets up a “scientific corner” at the Harrisonburg Farmers Market, offering people the chance to meet with astrophysicists (in the making) and discuss science. Our group members wear t-shirts with simple messages like “Ask me about the Sun,” “...about Black Holes and Mega-Masers” or “...about Big Bang” that initiate the dialog. We help our audience with observations of solar activity through our department’s Coronado telescope equipped with a safe H-alpha filter, sunspotters, and the incredibly simple yet durable and accurate handheld (Project Star) spectrometers, and invite them to the free Saturday Planetarium shows and the star parties hosted by our department on the JMU campus. The team is also prepared with a suite of fun activities aimed particularly at K-5 kids, e.g., building (and eating, after investigating out-gassing properties of) ”dirty comets,” making craters (in pans with flour or sand) and testing how different types of impactors (pebbles, ping-pong balls or even crumpled aluminum foil) affect crater formation, and demonstrations of shock wave created in supernova explosions. The main goals of this outreach program are: 1) to illustrate to people of all ages that science is a fun, creative, and exciting process; 2) to empower people to be curious and to ask questions; 3) to demonstrate that science is a viable career path chosen by many diverse individuals; and 4) to nurture a sense of wonder and awe for the Universe. While this outreach program is aimed at a very general audience, of an extremely wide range, we expect to produce a significant impact on K-12 students in general and in particular on the home-schooled kids. There is a relatively high

  20. Optical timing receiver for the NASA Spaceborne Ranging System. Part I. Dual peak-sensing timing discriminator

    International Nuclear Information System (INIS)

    Position-resolution capabilities of the NASA Spaceborne Laser Ranging System are essentially determined by the time-resolution capabilities of its optical timing receiver. The optical timing receiver consists of a fast photoelectric device; (e.g., photomultiplier or an avalanche photodiode detector), a timing discriminator, a high-precision event-timing digitizer, and a signal-processing system. The time-resolution capabilities of the receiver are determined by the photoelectron time spread of the photoelectric device, the time walk and resolution characteristics of the timing discriminator, and the resolution of the event-timing digitizer. It is thus necessary to evaluate available fast photoelectronic devices with respect to their time-resolution capabilities, to design a very low time walk timing discriminator and to develop a high-resolution event-timing digitizer which will be used in the high-resolution spaceborne laser ranging system receiver. The development of a new dual-peak sensing timing discriminator is described. The amplitude dependent time walk is less than +-150 psec for a 100:1 dynamic range of Gaussian-shaped input signals having pulse widths between 11 and 17 nsec. The unit produces 800 mV negative output pulses, each 10 nsec wide, and 3V positive pulses with widths of 15 nsec. The time delay through the discriminator is approximately 37 nsec. In this discriminator the input signal is processed by a peak-crossing circuit which produces a bipolar pulse having its zero-crossing point at the peak of the input signal. All essential functions in the discriminator are performed by means of tunnel diodes with backward diodes as nonlinear loads. The discriminator is designed to be CAMAC compatible to a conventional time-interval unit or a high-precision event timing digitizer. The adjustment procedure for obtaining minimum time walk is also given

  1. Uplink Performance Analysis of Multicell MU-MIMO Systems with ZF Receivers

    CERN Document Server

    Ngo, Hien Quoc; Duong, Trung Q; Larsson, Erik G

    2012-01-01

    We consider the uplink of a multicell multiuser multiple-input multiple-output system where the channel experiences both small and large-scale fading. The data detection is done by using the linear zero-forcing technique, assuming the base station (BS) has perfect channel state information. We derive exact closed-form expressions for the uplink rate, symbol error rate, and outage probability per user, as well as a lower bound on the achievable rate. This bound is very tight and becomes exact in the large-antenna limit. We further study the asymptotic performance of the system in the regimes of high signal-to-noise ratio (SNR), large number of antennas, and large number of users per cell. We show that, at high SNRs, the system is interference-limited and hence, we cannot improve the system performance by increasing the transmit power of each user. Instead, by increasing the number of BS antennas, the effects of interference and noise can be reduced, thereby improving the system performance. We further demonstr...

  2. New approach for receiving water objectives for overflows from sewer systems

    DEFF Research Database (Denmark)

    Larsen, Torben

    1999-01-01

    The paper describes the results of the work for the establishment of consistent objectives for storm overflows from sewer systems in respect to the physical conditions in streams and rivers in Denmark. First the result of a questionnaire is mentioned. Next some principles of the methods for formu......The paper describes the results of the work for the establishment of consistent objectives for storm overflows from sewer systems in respect to the physical conditions in streams and rivers in Denmark. First the result of a questionnaire is mentioned. Next some principles of the methods...

  3. ANALYSIS OF A CUMULANT-BASED 2D-RAKE RECEIVER FOR CDMA SYSTEM OVER FREQUENCY-SELECTIVE FADING CHANNELS

    Institute of Scientific and Technical Information of China (English)

    杨维; 程时昕

    2003-01-01

    The conventional 2D-Rake receivers for code-division multiple access (CDMA) system over frequency-selective fading channels are generally based on the second-order statistics while assuming perfect array conditions. However, the sensor response, location uncertainty, and the use of sample statistics can severely degrade the performance of second-order statistics processing. And in practical application, it is impossible to calibrate the array frequently. In this paper a cumulant-based 2D-Rake receiver for synchronous CDMA system with decorrelator is presented. Decorrelating is a multi-user detection approach that not only provides a fundamental solution to the mutual interference problem in CDMA communications but also makes it convenient for the decoupled signal to be processed spatially and temporally. High-order signal processing has some inherent advantages over that of second-order. Employing second-order statistics it is impossible to estimate source steering vector blindly, while employing higher than second-order cumulants, this purpose can be achieved. The performance analysis shows that employing cumulant-based signal processing technique the proposed 2D-Rake receiver is blind and demonstrates excellent performance.

  4. An artificial vision-based control system for automatic heliostat positioning offset correction in a central receiver solar power plant

    Energy Technology Data Exchange (ETDEWEB)

    Berenguel, M. [Universidad de Almeria, Dept. de Lenguajes y Computacion, La Canada Almeria (Spain); Rubio, F.R.; Lara, P.J.; Arahal, M.R.; Camacho, E.F.; Lopez, M. [Universidad de Sevilla, Dept. de Ingenieria de Sistemas y Automatica, Sevilla (Spain); Valverde, A. [Plataforma Solar de Almeria (PSA-CIEMAT), Tabernas (Almeria) (Spain)

    2004-07-01

    This paper presents the development of a simplified and automatic heliostat positioning offset correction control system using artificial vision techniques and common CCD devices. The heliostats of a solar power plant reflect solar radiation onto a receiver (in this case, a volumetric receiver) placed at the top of a tower in order to provide a desired energy flux distribution correlated with the coolant flow (in this case air mass flow) through the receiver, usually in an open loop control configuration. There exist error sources that increase the complexity of the control system, some of which are systematic ones, mainly due to tolerances, wrong mirror facets alignment (optical errors), errors due to the approximations made when calculating the solar position, etc., that produce errors (offsets) in the heliostat orientation (aiming point). The approximation adopted in this paper is based on the use of a B/W CCD camera to correct these deviations in an automatic way imitating the same procedure followed by the operators. The obtained images are used to estimate the distance between the sunbeam centroid projected by the heliostats and a target placed on the tower, this distance thus is used for low accuracy offset correction purposes. Basic threshold-based image processing techniques are used for automatic correction. (Author)

  5. Babylonian and Indian Astronomy Early Connections

    CERN Document Server

    Kak, S

    2003-01-01

    Did the Indian and Babylonian astronomy evolve in isolation, was there mutual influence, or was one dependent on the other? Scholars have debated these questions for more than two centuries, and opinion has swung one way or the other with time. The similarities between the two systems that have been investigated are: the use of 30 divisions of the lunar month; the 360 divisions of the civil year; the length of the year; and the solar zodiac. Some have wondered if the Babylonian planetary tables might have played a role in the theories of the siddhantas. I shall in this essay go over the essentials of the early Indian and Babylonian astronomy and summarize the latest views on the relationship between them. I shall show that the key ideas found in the Babylonian astronomy of 700 BC are already present in the Vedic texts, which even by the most conservative reckoning are centuries older than this period. I shall also show that the solar zodiac (rashis) was used in Vedic India and I shall present a plausible deri...

  6. Big Computing in Astronomy: Perspectives and Challenges

    Science.gov (United States)

    Pankratius, Victor

    2014-06-01

    Hardware progress in recent years has led to astronomical instruments gathering large volumes of data. In radio astronomy for instance, the current generation of antenna arrays produces data at Tbits per second, and forthcoming instruments will expand these rates much further. As instruments are increasingly becoming software-based, astronomers will get more exposed to computer science. This talk therefore outlines key challenges that arise at the intersection of computer science and astronomy and presents perspectives on how both communities can collaborate to overcome these challenges.Major problems are emerging due to increases in data rates that are much larger than in storage and transmission capacity, as well as humans being cognitively overwhelmed when attempting to opportunistically scan through Big Data. As a consequence, the generation of scientific insight will become more dependent on automation and algorithmic instrument control. Intelligent data reduction will have to be considered across the entire acquisition pipeline. In this context, the presentation will outline the enabling role of machine learning and parallel computing.BioVictor Pankratius is a computer scientist who joined MIT Haystack Observatory following his passion for astronomy. He is currently leading efforts to advance astronomy through cutting-edge computer science and parallel computing. Victor is also involved in projects such as ALMA Phasing to enhance the ALMA Observatory with Very-Long Baseline Interferometry capabilities, the Event Horizon Telescope, as well as in the Radio Array of Portable Interferometric Detectors (RAPID) to create an analysis environment using parallel computing in the cloud. He has an extensive track record of research in parallel multicore systems and software engineering, with contributions to auto-tuning, debugging, and empirical experiments studying programmers. Victor has worked with major industry partners such as Intel, Sun Labs, and Oracle. He holds

  7. Analysis of mail receiving system based on Java%基于Java的邮件接收系统分析

    Institute of Scientific and Technical Information of China (English)

    宋佳颖

    2015-01-01

    In the era of the rapid development of global information, the Internet technology continuous progress and development, e-mail system has become indispensable tools. Through the java development of a mail receiving system, users convenient and efficient management of their mail, can be more easily to mail management and maintenance, the development of the system based on java mail receiving system. The system adopts Java as the development language, and use SQL Server as the background database, is a comprehensive design.%在全球信息化飞速发展的时代,互联网技术不断进步与发展,电子邮件系统已经成为人们必不可少的工具.通过Java开发一套邮件接收系统,可以使用户方便快捷地管理邮件,可以更轻松地对邮件进行维护,本系统开发基于Java的邮件接收系统.文章分析了系统采用Java作为开发语言,并用SQL Server作为后台数据库,是一个综合的设计.

  8. Nutrient cycling in an agroforestry alley cropping system receiving poultry litter or nitrogen fertilizer

    Science.gov (United States)

    Optimal utilization of animal manures as a plant nutrient source should also prevent adverse impacts on water quality. The objective of this study was to evaluate long-term poultry litter and N fertilizer application on nutrient cycling following establishment of an alley cropping system with easter...

  9. Scalable Multifunction RF Systems: Combined vs. Separate Transmit and Receive Arrays

    NARCIS (Netherlands)

    Huizing, A.G.

    2008-01-01

    A scalable multifunction RF (SMRF) system allows the RF functionality (radar, electronic warfare and communications) to be easily extended and the RF performance to be scaled to the requirements of different missions and platforms. This paper presents the results of a trade-off study with respect to

  10. Large Databases in Astronomy

    Science.gov (United States)

    Szalay, Alexander S.; Gray, Jim; Kunszt, Peter; Thakar, Anirudha; Slutz, Don

    The next-generation astronomy digital archives will cover most of the sky at fine resolution in many wavelengths, from X-rays through ultraviolet, optical, and infrared. The archives will be stored at diverse geographical locations. The intensive use of advanced data archives will enable astronomers to explore their data interactively. Data access will be aided by multidimensional spatial and attribute indices. The data will be partitioned in many ways. Small tag indices consisting of the most popular attributes will accelerate frequent searches. Splitting the data among multiple servers will allow parallel, scalable I/O and parallel data analysis. Hashing techniques will allow efficient clustering, and pair-wise comparison algorithms that should parallelize nicely. Randomly sampled subsets will allow debugging otherwise large queries at the desktop. Central servers will operate a data pump to support sweep searches touching most of the data. The anticipated queries will require special operators related to angular distances and complex similarity tests of object properties, like shapes, colors, velocity vectors, or temporal behaviors. These issues pose interesting data management challenges.

  11. Astronomy and Atmospheric Optics

    Science.gov (United States)

    Cowley, Les; Gaina, Alex

    2011-12-01

    The authors discusse the insuccess of the observation of the Total Eclipse of the Moon from 10 december 2011 in Romania and relate them with meteoconditions. Only a very short part of the last penumbral phase was observed, while the inital part and the totality was not observed due to very dense clouds. The change in color and brightness during this phase was signaled. Meanwhile, there is an area of science where clouds are of great use and interest. This area is Atmospheric optics, while the science which study clouds is meteorology. Clouds in combination with Solar and Moon light could give rise to a variety of strange, rare and unobvious phenomena in the atmosphere (sky), sometimes confused with Unidentified Flying Objects (UFO). The importance of meteorology for astronomy and atmospheric optics is underlined and an invitation to astronomers to use unfavourable days for athmospheric observations was sent. The web address of the site by Les Cowley, designed for atmospheric optics phenomena is contained in the text of the entry.

  12. Grab 'n' go astronomy

    CERN Document Server

    English, Neil

    2014-01-01

      Like everyone else, most amateur astronomers live busy lives. After a long day, the last thing you want as an observer is to have to lug out a large telescope and spend an hour getting it ready before it can be used. Maybe you are going somewhere sure to have dark skies, but you don’t necessarily want astronomy to dominate the trip. Or you are not quite committed to owning a large telescope, but curious enough to see what a smaller, portable setup can accomplish. These are times when a small “grab ’n’ go” telescope, or even a pair of binoculars, is the ideal in­strument. And this book can guide you in choosing and best utilizing that equipment.   What makes a telescope fall into the “grab ’n’ go” category? That’s easy – speed of setting up, ease of use, and above all, portability. This ambitious text is dedicated to those who love to or – because of their limited time – must observe the sky at a moment’s notice. Whether observing from the comfort of a backyard or while on busi...

  13. Edible Astronomy Demonstrations

    Science.gov (United States)

    Lubowich, Donald A.

    2007-12-01

    Astronomy demonstrations with edible ingredients are an effective way to increase student interest and knowledge of astronomical concepts. This approach has been successful with all age groups from elementary school through college students - and the students remember these demonstrations after they are presented. In this poster I describe edible demonstrations I have created to simulate the expansion of the universe (using big-bang chocolate chip cookies); differentiation during the formation of the Earth and planets (using chocolate or chocolate milk with marshmallows, cereal, candy pieces or nuts); and radioactivity/radioactive dating (using popcorn). Other possible demonstrations include: plate tectonics (crackers with peanut butter and jelly); convection (miso soup or hot chocolate); mud flows on Mars (melted chocolate poured over angel food cake); formation of the Galactic disk (pizza); formation of spiral arms (coffee with cream); the curvature of Space (Pringles); constellations patterns with chocolate chips and chocolate chip cookies; planet shaped cookies; star shaped cookies with different colored frostings; coffee or chocolate milk measurement of solar radiation; Oreo cookie lunar phases. Sometimes the students eat the results of the astronomical demonstrations. These demonstrations are an effective teaching tool and can be adapted for cultural, culinary, and ethnic differences among the students.

  14. Astronomy Research Seminar

    Science.gov (United States)

    Johson, Jolyon; Genet, Russell; Armstrong, James; Boyce, Grady; Boyce, Pat; Brewer, Mark; Buchheim, Robert; Carro, Joseph; Estrada, Reed; Estrada, Chris; Freed, Rachel; Gillette, Sean; Harshaw, Richard; Hollis, Thomas; Kenney, John; McGaughey, Seven; McNab, Christine; Mohanan, Kakkala; Sepulveda, Babs; Wallace, Dan; Wallen, Vera

    2015-05-01

    Traditional science lectures and labs are often enhanced through project- and team-based learning. Some students go beyond these classroom studies by conducting research, often under the guidance of university professors. A one-semester astronomy research seminar was initiated in 2006 in collaboration with the community of professional and amateur double star astronomers. The result was dozens of jointly-authored papers published in the Journal of Double Star Observations and the Annual Proceedings of the Society of Astronomical Sciences. This seminar, and its affiliated community, launched a series of conferences and books, providing students with additional forums to share their double star research. The original seminar, and its derivatives, enhanced educational careers through college admissions and scholarships. To expand the seminar's reach, it was restructured from a few teams at one school, to many teams, each from a different school. A volunteer from each school became an assistant instructor. Most of them were seminar veterans, experienced astronomers, or science teachers. The assistant instructors, in turn, recruited enthusiastic students for their teams. To avoid student and instructor overload, the seminar focused on its three deliverables: a formal proposal, published paper, and public PowerPoint presentation. Future seminars may offer other astronomical research options such as exoplanet transit or eclipsing binary photometry.

  15. Prehistoric Astronomy in China

    Science.gov (United States)

    Chiu, B. C.

    2000-05-01

    We do not have definite proof, but the situation is very interesting, so here is a summary of what we have from calculations and literature research. The ancient Classics of China were written in an archaic, terse language. But the philologist, Bernhard Karlgren, was able to argue that the constellations, (Niao, Huo, Hsu, Mao) were what the oldest stories referred to when the Sage Yao gave directions for agriculture by use of astronomy. Huo and Mao are now well-identified as the asterisms, Antares and the Pleiades. And using tables of precession, which we now have, we find that the text gives a date thousands of years earlier than previously thought. Together with results from studies in prehistory in the last two decades, we can form a plausible picture of how the Pleiades, and then Antares were observed, telling of the beginning of warming, and then the beginning of harvest. We have had at least two obstacles to overcome: one, we had to show the stories were written earlier than one thousand years ago because the Chinese knew of precession then and could have made up the story. Secondly, that the `culmination' written about by Joseph Needham probably referred to a much later time.

  16. Astronomy in India a historical perspective

    CERN Document Server

    2014-01-01

    India has a strong and ancient tradition of astronomy, which seamlessly merges with the current activities in Astronomy and Astrophysics in the country. While the younger generation of astronomers and students are reasonably familiar with the current facilities and the astronomical research, they might not have an equally good knowledge of the rich history of Indian astronomy. This particular volume, brought out as a part of the Platinum Jubilee Celebrations of Indian National Science Academy, concentrates on selected aspects of historical development of Indian astronomy in the form of six invited chapters. Two of the chapters – by Balachandra Rao and M.S. Sriram – cover ancient astronomy and the development of calculus in the ancient Kerela text Yuktibhasa. The other four chapters by B.V. Sreekantan, Siraj Hasan, Govind Swarup and Jayant Narlikar deal with the contemporary history of Indian astronomy covering space astronomy, optical astronomy, radio astronomy and developments in relativistic astrophysic...

  17. Wireless power-receiving assembly for a telemetry system in a high-temperature environment of a combustion turbine engine

    Energy Technology Data Exchange (ETDEWEB)

    Bevly, III, Alex J.; McConkey, Joshua S.

    2016-08-16

    In a telemetry system (100) in a high-temperature environment of a combustion turbine engine (10), a wireless power-receiving coil assembly (116) may be affixed to a movable component (104) of the turbine engine. Power-receiving coil assembly (116) may include a radio-frequency transparent housing (130) having an opening (132). A lid (134) may be provided to close the opening of the housing. Lid (134) may be positioned to provide support against a surface (120) of the movable component. An induction coil (133) is disposed in the housing distally away from the lid and encased between a first layer (136) and a last layer (140) of a potting adhesive. Lid (134) is arranged to provide vibrational buffering between the surface (120) of the movable component (104) and the layers encasing the induction coil.

  18. Astronomy education and scientific schools in Ukraine

    Science.gov (United States)

    Yatskiv, Yaroslav S.; Vavilova, Iryna B.

    2011-06-01

    We describe briefly the current state of astronomical education in Ukraine, namely the secondary, higher, and post-graduating education systems. A special attention is paid to so called ``scientific schools'', non-formal groups of scientists formed by recognised astronomers, which have played and continue to play an important rôle in development of the astronomy education system. Among the founders of scientific schools were the well-known professors Alexander Ya. Orlov (Odessa University), Nikolai P. Barabashov (Kharkiv University), Sergei K. Vsekhsvyatsky (Kyiv University), Semen Ya. Braude (Kharkiv Polytechnical Institute), and Vladimir P. Tsesevich (Odessa University). We also give a general review on the history of astronomy education during the 16th-18th centuries. In 2000 astronomy was reinstated into the current 12-year secondary education curriculum of Ukraine. At present, some elements of astronomical knowledge are included in the lessons of ``Natural Sciences'' for pupils in the 5th - 10th grades. Astronomy is included as a basic course both in general (non-specialised) schools (17 academic hours in the last 11th or 12th grade) and in lyceums of the natural sciences (34 academic hours in the 12th grade). It is included also as an optional course in the educational program of gymnasiums in humanities. Every year about 75 young persons enter the Ukrainian universities to become astronomers. Results of our monitoring of the efficiency of astronomical higher educational system indicate that about 80% of the entered university students finish their education in 5 years; 50% of those who finished the cursus were working in astronomy. Since 1992 more then 100 astronomers defend Theses of Cand. Sci. (similar to Ph.D) and about 40 astronomers defend Theses of Dr. Sci. (topmost scientific degree, similar to Dr. Hab.). One of our present-day problems is a brain drain of young scientists. About 50% of those who obtained Cand. Sci. degree work outside Ukraine. At

  19. Radio astronomy in Africa: the case of Ghana

    CERN Document Server

    Asabere, Bernard Duah; Horellou, Cathy; Winkler, Hartmut; Jarrett, Thomas

    2015-01-01

    South Africa has played a leading role in radio astronomy in Africa with the Hartebeesthoek Radio Astronomy Observatory (HartRAO). It continues to make strides with the current seven-dish MeerKAT precursor array (KAT-7), leading to the 64-dish MeerKAT and the giant Square Kilometer Array (SKA), which will be used for transformational radio astronomy research. Ghana, an African partner to the SKA, has been mentored by South Africa over the past six years and will soon emerge in the field of radio astronomy. The country will soon have a science-quality 32m dish converted from a redundant satellite communication antenna. Initially, it will be fitted with 5 GHz and 6.7 GHz receivers to be followed later by a 1.4 - 1.7 GHz receiver. The telescope is being designed for use as a single dish observatory and for participation in the developing African Very Long Baseline Interferometry (VLBI) Network (AVN) and the European VLBI Network. Ghana is earmarked to host a remote station during a possible SKA Phase 2. The loca...

  20. Comparison of intelligence quotient in children surviving leukemia who received different prophylactic central nervous system treatments

    OpenAIRE

    Reisi Nahid; Khalilian Leila

    2012-01-01

    Background: Neurocognitive deficits and decrease in intelligence quotient (IQ) is one of the complication of prophylactic central nervous system (CNS) treatment in acute lymphoblastic leukemia (ALL) patients. In this study, we compare the IQ in survivors of ALL that were treated with different prophylactic CNS treatments. Materials and Methods : We compared 43 long-term survivors of ALL: 21 survivors with intrathecal methotrexate (IT MTX) as CNS prophylaxis, 22 with IT MTX+1800-2400 rads c...

  1. Solar gas turbine systems with centrifugal particle receivers, for remote power generation

    OpenAIRE

    Prosin, Tobias; Pryor, Trevor; Creagh, Christine; Amsbeck, Lars; Uhlig, Ralf

    2015-01-01

    There is a growing demand from remote communities in Australia to increase the amount of decentralised renewable energy in their energy supply mix in order to decrease their fuel costs. In contrast to large scale concentrated solar power (CSP) plants, small solar-hybrid gas turbine systems promise a way to decentralise electricity generation at power levels in the range of 0.1- 10 MWe, and reduce to cost of energy production for off-grid, isolated communities. Thermal storage provides such...

  2. AstronomyCenter.org - A Digital Library for Astronomy 101

    Science.gov (United States)

    Gagne, M.; Monahan, P.; Deustua, S.; Mason, B.

    2004-12-01

    The AAS is sponsoring the development of a digital collection of online resources for teaching introductory astronomy: astronomycenter.org. Astronomy Center is part of the ComPADRE project with the AIP and its member organizations (see Deustua et al. at this meeting). The goal of Astronomy Center is to build a portal that will be a broad collection of high-quality digital resources, a useful and inviting interface to search and browse the collection, and an online meeting place for faculty at a variety of institutions to gather and share information. The collection will be launched in early 2005 and will initially contain a few hundred resources, selected primarily by Astronomy Center staff. The collection will grow through user and author submissions. Meanwhile, resources will be peer-reviewed and featured on the site as the collection grows. We will present the astronomycenter.org site, the user interface, some resources in the collection, the peer review process, and how members of the community can get involved with Astronomy Center. This work was made possible by a NSF National Science, Technology, Engineering and Mathematics Digital Library (NSDL) grant to the AAPT, AIP, and AAS.

  3. A Grand Vision for European Astronomy

    Science.gov (United States)

    2007-09-01

    Today, and for the first time, astronomers share their global Science Vision for European Astronomy in the next two decades. This two-year long effort by the ASTRONET network of funding agencies, sponsored by the European Commission and coordinated by INSU-CNRS, underscores Europe's ascension to world leadership in astronomy and its will to maintain that position. It will be followed in just over a year by a prioritised roadmap for the observational facilities needed to implement the Vision. Implementation of these plans will ensure that Europe fully contributes to Mankind's ever deeper understanding of the wonders of our Universe. astronet logo "This is a great opportunity to help create a vibrant long-term future for astronomy and science" says Tim de Zeeuw (Leiden Observatory, The Netherlands) who led this community-wide effort. The ASTRONET Science Vision provides a comprehensive overview of the most important scientific questions that European astronomy should address in the next twenty years. The four key questions are the extremes of the Universe, from the nature of the dark matter and dark energy that comprise over 95% of the Universe to the physics of extreme objects such as black holes, neutron stars, and gamma-ray bursts; the formation of galaxies from the first seeds to our Milky Way; the formation of stars and planets and the origin of life; and the crucial question of how do we (and our Solar System) fit in the global picture. These themes reach well beyond the realm of traditional astronomy into the frontiers of physics and biology. The Vision identifies the major new facilities that will be needed to achieve these goals, but also stresses the need for parallel developments in theory and numerical simulations, high-performance computing resources, efficient astronomical data archiving and the European Virtual Observatory, as well as in laboratory astrophysics. "This report is a key input for the even more challenging task of developing a prioritised

  4. BOOK REVIEW: Astronomie und Anschaulichkeit. Die Bilder der populaeren Astronomie des 19. Jahrhunderts

    Science.gov (United States)

    Duerbeck, H. W.; Utzt, S.

    2004-12-01

    Today, popularisation of science also means "pretty pictures": images that accompany articles in magazines and webpages, or are squeezed between the covers of so-called coffee-table books, and the reviewer pleads guilty to having added to this growing pile. But how did this "disease" came into existence? Susanne Utzt, a manager, journalist and student in the history of sciences, has dedicated her master thesis to the investigation of the growing influence of such pictures in the popularisation of astronomy. She has analyzed French and German popular texts by Arago, Guillemin, Flammarion, as well as Littrow, Maedler and Max Wilhelm Meyer that mainly appeared in the second half of the 19th century. Earlier astronomy books just had a few foldout pages with mathematical figures, as the author exemplifies by Littrow's first edition of "Die Wunder des Himmels" of 1834-36. But Flammarion with his "Astronomie Populaire", changed everything: 51 "art pages" and more than 300 figures in the text made it a true picture book, and about a third of Utzt's work is dedicated to its analysis. (In passing, it should be noted that the first 1880 edition of Flammarion's book did not yet contain the "art pages"; the author quotes such pages and text figures according to a German edition of 1907). Besides sober diagrams illustrating the solar system, and telescope drawings showing planetary surfaces and the structure of the solar photosphere, Flammarion includes poetic illustrations like a couple at the seashore at sunset; a scene showing dying Copernicus, already flanked by two angels, as he receives a copy of his De Revolutionibus; or a painting showing a flock of mammoths in an ancient landscape. In most cases, the images are chosen to illustrate the text, but sometimes the text "makes a detour" to permit the inclusion of a pretty picture. Flammarion's book contains drawings illustrating the sphericity of the earth, which appeared in almost identical form in Apian's Cosmography of

  5. Introducing Astronomy into Mozambican Society

    CERN Document Server

    Ribeiro, V A R M; Besteiro, A M A R; Geraldes, H; Maphossa, A M; Nhanonbe, F A; Uaissine, A J R

    2009-01-01

    Mozambique has been proposed as a host for one of the future Square Kilometre Array stations in Southern Africa. However, Mozambique does not possess a university astronomy department and only recently has there been interest in developing one. South Africa has been funding students at the MSc and PhD level, as well as researchers. Additionally, Mozambicans with Physics degrees have been funded at the MSc level. With the advent of the International Year of Astronomy, there has been a very strong drive, from these students, to establish a successful astronomy department in Mozambique. The launch of the commemorations during the 2008 World Space Week was very successful and Mozambique is to be used to motivate similar African countries who lack funds but are still trying to take part in the International Year of Astronomy. There hare been limited resources and funding, however there is a strong will to carry this momentum into 2009 and, with this, influence the Government to introduce Astronomy into its nationa...

  6. Low complexity MIMO receivers

    CERN Document Server

    Bai, Lin; Yu, Quan

    2014-01-01

    Multiple-input multiple-output (MIMO) systems can increase the spectral efficiency in wireless communications. However, the interference becomes the major drawback that leads to high computational complexity at both transmitter and receiver. In particular, the complexity of MIMO receivers can be prohibitively high. As an efficient mathematical tool to devise low complexity approaches that mitigate the interference in MIMO systems, lattice reduction (LR) has been widely studied and employed over the last decade. The co-authors of this book are world's leading experts on MIMO receivers, and here they share the key findings of their research over years. They detail a range of key techniques for receiver design as multiple transmitted and received signals are available. The authors first introduce the principle of signal detection and the LR in mathematical aspects. They then move on to discuss the use of LR in low complexity MIMO receiver design with respect to different aspects, including uncoded MIMO detection...

  7. Systemic capillary leak syndrome in a patient receiving adjuvant oxaliplatin for locally advanced colon cancer.

    Science.gov (United States)

    Anderson, Brandon J; Peterson, Lindsay L

    2016-10-01

    Colorectal cancer is the third most common cancer diagnosed in the USA each year. Oxaliplatin, a platinum-based chemotherapy agent, is part of the standard adjuvant chemotherapy regimen FOLFOX (oxaliplatin with 5-fluorouracil [5-FU] and leucovorin [LV]) for the treatment of stage III and some high-risk stage II colorectal cancers. Although oxaliplatin is generally well tolerated, certain side effects such as nausea, vomiting, and peripheral neuropathy are common. We report a case of oxaliplatin-induced capillary-leak syndrome in a 63-year-old man undergoing his 12th and final cycle of FOLFOX for stage III colorectal cancer. To our knowledge, this is the first case of systemic capillary leak syndrome (SCLS) reported in association with oxaliplatin. Currently, there is no prevention for SCLS. Documenting future cases of SCLS attributed to oxaliplatin is vital, as SCLS is associated with significant morbidity and mortality and no standard treatments beyond supportive care measures exist. Early recognition and diagnosis are therefore essential to improving patient outcomes. PMID:26071595

  8. AstroJazz: Integrating Live Jazz and Astronomy Education

    Science.gov (United States)

    Morrow, C. A.

    2005-12-01

    AstroJazz is an innovative public education program in astronomy that blends stunning imagery with live jazz music and a touch of humor to awaken the cosmic curiosity of both adults and children. The program debuted in February 2005 at the Fiske Planetarium on the campus of the University of Colorado, Boulder with an astronomer-chanteuse (the author), a pianist, bassist, drummer, and technical assistant who created dome effects to compliment the PowerPoint slides associated with each song. This AstroJazz quartet played ten songs, five original tunes (Look Up!, Are We Alone? Andromeda Affaire, StarMan Blues, Star Kissed)), and five standard tunes with lyrical twists toward astronomy & astrobiology (e.g. Stormy Weather - Solar Style and Stardust a la SETI.) The hour-long program also includes educational interludes where the astronomy chanteuse interacts with the audience, providing insights and perspective into the wonders of our universe. The performance program that is handed to all audience members contains additional "gee-whiz" facts and provides leads to websites like Astronomy Picture of the Day and spaceweather.com that provide ongoing points of contact for public interest in astronomy. AstroJazz was very well received in its debut performance and now has several new opportunities to perform. Anecdotal evidence suggests that the AstroJazz program is engaging and educational for a very broad audience, including families with young children, world-class astronomers, and spouses of musicians who had never before been exposed to astronomy. This paper will describe the origins and intended evolution of AstroJazz, and offer a mini-sample of the music and slides used in the program. It will also discuss strategies for how the impact on audiences might be assessed.

  9. Solar central receiver hybrid power system, Phase I. Volume 2. Conceptual design. Final technical report, October 1978-August 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-09-01

    The objectives of this study were to develop a hybrid power system design that (1) produces minimum cost electric power, (2) minimizes the capital investment and operating cost, (3) permits capacity displacement, (4) and achieves utility acceptance for market penetration. We have met the first three of these objectives and therefore believe that the fourth, utility acceptance, will become a reality. These objectives have been met by utilizing the Martin Marietta concept that combines the alternate central receiver power system design and a high-temperature salt primary heat transfer fluid and thermal storage media system with a fossil-fired nonsolar energy source. Task 1 reviewed the requirements definition document and comments and recommendations were provided to DOE/San Francisco. Task 2 consisted of a market analysis to evaluate the potential market of solar hybrid power plants. Twenty-two utilities were selected within nine regions of the country. Both written and verbal correspondence was used to assess solar hybrid power plants with respect to the utilities' future requirements and plans. The parametric analysis of Task 3 evaluated a wide range of subsystem configurations and sizes. These analyses included subsystems from the solar standalone alternate central receiver power system using high-temperature molten salt and from fossil fuel nonsolar subsystems. Task 4, selection of the preferred commerical system configuration, utilized the parametric analyses developed in Task 3 to select system and subsystem configurations for the commercial plant design. Task 5 developed a conceptual design of the selected commercial plant configuration and assessed the related cost and performance. Task 6 assessed the economics and performance of the selected configuration as well as future potential improvements or limitations of the hybrid power plants.

  10. A~compact receiver system for simultaneous measurements of mesospheric CO and O3

    Directory of Open Access Journals (Sweden)

    P. Forkman

    2015-09-01

    Full Text Available During the last decades, ground-based microwave radiometry has matured to an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H2O and O3 can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites, more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is today urgent as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O3 at 110.84 GHz is presented The radiometer, its calibration scheme and observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuation at the two frequencies, and error characterization are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO, (57° N, 12° E is analysed. The retrieved vertical profiles are compared with co-located CO and O3 data from the MLS instrument on the Aura satellite. The datasets from the instruments agree well to each other. The main differences are the higher OSO volume mixing ratios of O3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low

  11. A compact receiver system for simultaneous measurements of mesospheric CO and O3

    Science.gov (United States)

    Forkman, P.; Christensen, O. M.; Eriksson, P.; Billade, B.; Vassilev, V.; Shulga, V. M.

    2016-02-01

    During the last decades, ground-based microwave radiometry has matured into an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high-altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H2O, and O3, can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites; more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is urgent today as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O3 at 110.84 GHz is presented. The radiometer, its calibration scheme, and its observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuations at the two frequencies and error characterization, are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO (57° N, 12° E), is analysed. The retrieved vertical profiles are compared with co-located CO and O3 data from the MLS instrument on the Aura satellite. The data sets from the instruments agree well with each other. The main differences are the higher OSO volume mixing ratios of O3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low bias

  12. Receiver system for radio observation of high-energy cosmic ray air showers and its behaviour in self trigger mode

    International Nuclear Information System (INIS)

    The observation of high-energy cosmic rays is carried out by indirect measurements. Thereby the primary cosmic particle enters into the earth's atmosphere and generates a cosmic ray air shower by interactions with the air molecules. The secondary particles arriving at ground level are detected with particle detector arrays. The fluorescence light from the exited nitrogen molecules along the shower axis is observed with reflector telescopes in the near-ultraviolet range. In addition to these well-established detection methods, the radio observation of the geosynchrotron emission from cosmic ray air showers is investigated at present as a new observation method. Geosynchrotron emission is generated by the acceleration of the relativistic electron-positron-pairs contained in the air shower by Lorentz forces in the earth's magnetic field. At ground level this causes a single pulse of the electric field strength with a continuous frequency spectrum ranging from a few MHz to above 100 MHz. In this work, a suitable receiver concept is developed based on the signal properties of the geosynchrotron emission and the analysis of the superposed noise and radio frequency interferences. As the required receiver system was not commercially available, it was designed in the framework of this work and realised as system including the antenna, the receiver electronics and suitable data acquisition equipment. In this concept considerations for a large scale radio detector array have already been taken into account, like low power consumption to enable solar power supply and cost effectiveness. The result is a calibrated, multi-channel, digital wideband receiver for the complete range from 40 MHz to 80 MHz. Its inherent noise and RFI suppression essentially results from the antenna directional characteristic and frequency selectivity and allows effective radio observation of cosmic ray air showers also in populated environment. Several units of this receiver station have been deployed

  13. GLORI (GLObal navigation satellite system Reflectometry Instrument): A New Airborne GNSS-R receiver for land surface applications

    Science.gov (United States)

    Motte, Erwan; Zribi, Mehrez; Fanise, Pascal

    2015-04-01

    GLORI (GLObal navigation satellite system Reflectometry Instrument) is a new receiver dedicated to the airborne measurement of surface parameters such as soil moisture and biomass above ground and sea state (wave height and direction) above oceans. The instrument is based on the PARIS concept [Martin-Neira, 1993] using both the direct and surface-reflected L-band signals from the GPS constellation as a multistatic radar source. The receiver is based on one up-looking and one down-looking dual polarization hemispherical active antennas feeding a low-cost 4-channel SDR direct down-conversion receiver tuned to the GPS L1 frequency. The raw measurements are sampled at 16.368MHz and stored as 2-bit, IQ binary files. In post-processing, GPS acquisition and tracking are performed on the direct up-looking signal while the down-looking signal is processed blindly using tracking parameters from the direct signal. The obtained direct and reflected code-correlation waveforms are the basic observables for geophysical parameters inversion. The instrument was designed to be installed aboard the ATR42 experimental aircraft from the French SAFIRE fleet as a permanent payload. The long term goal of the project is to provide real-time continuous surface information for every flight performed. The aircraft records attitude information through its Inertial Measurement Unit and a commercial GPS receiver records additional information such as estimated doppler and code phase, receiver location, satellites azimuth and elevation. A series of test flights were performed over both the Toulouse and Gulf of Lion (Mediterranean Sea) regions during the period 17-21 Nov 2014 together with the KuROS radar [Hauser et al., 2014]. Using processing methods from the literature [Egido et al., 2014], preliminary results demonstrate the instrument sensitivity to both ground and ocean surface parameters estimation. A dedicated scientific flight campaign is planned at the end of second quarter 2015 with

  14. Astronomy education through interactive materials

    Science.gov (United States)

    Voelzke, Marcos Rincon; Antunes de Macêdo, Josué

    2015-08-01

    This study presents results of a survey conducted at the Federal Institution of Education, Science and Technology in the North of Minas Gerais (IFNMG), and aimed to investigate the potentialities of the use of interactive materials in the teaching of astronomy. An advanced training course with involved learning activities about basic concepts of astronomy was offered to thirty-two Licenciate students in Physics, Mathematics and Biological Sciences, using the mixed methodology, combined with the three pedagogical moments. Among other aspects, the viability of the use of resources was noticed, involving digital technologies and interactive materials on teaching of astronomy, which may contribute to the broadening of methodological options for future teachers and meet their training needs.

  15. Scientific literacy: astronomy at school

    Science.gov (United States)

    Gangui, A.; Iglesias, M.; Quinteros, C.

    Models constructed by scientists to explain the world often incorporate their actual individual conceptions about different physical phenomena. Likewise, prospective teachers reach general science courses with preconstructed and consistent models of the universe surrounding them. In this project we present a series of basic questionings that make us reflect on the present situation of the teaching-learning relationship in astronomy within the framework of formal education for elementary school teachers. Our project main aims are: 1) to contribute to finding out the real learning situation of preservice elementary teachers, and 2) from these studies, to try and develop didactic tools that can contribute to improve their formal education in topics of astronomy. In spite of being of chief importance within the science teaching topics, mainly due to its interdisciplinarity and cultural relevance, researches in didactics of astronomy are not well represented in our research institutes. FULL TEXT IN SPANISH

  16. On Fast Post-Processing of Global Positioning System Simulator Truth Data and Receiver Measurements and Solutions Data

    Science.gov (United States)

    Kizhner, Semion; Day, John H. (Technical Monitor)

    2000-01-01

    Post-Processing of data related to a Global Positioning System (GPS) simulation is an important activity in qualification of a GPS receiver for space flight. Because a GPS simulator is a critical resource it is desirable to move off the pertinent simulation data from the simulator as soon as a test is completed. The simulator data files are usually moved to a Personal Computer (PC), where the post-processing of the receiver logged measurements and solutions data and simulated data is performed. Typically post-processing is accomplished using PC-based commercial software languages and tools. Because of commercial software systems generality their general-purpose functions are notoriously slow and more than often are the bottleneck problem even for short duration experiments. For example, it may take 8 hours to post-process data from a 6-hour simulation. There is a need to do post-processing faster, especially in order to use the previous test results as feedback for a next simulation setup. This paper demonstrates that a fast software linear interpolation algorithm is applicable to a large class of engineering problems, like GPS simulation data post-processing, where computational time is a critical resource and is one of the most important considerations. An approach is developed that allows to speed-up post-processing by an order of magnitude. It is based on improving the post-processing bottleneck interpolation algorithm using apriori information that is specific to the GPS simulation application. The presented post-processing scheme was used in support of a few successful space flight missions carrying GPS receivers. A future approach to solving the post-processing performance problem using Field Programmable Gate Array (FPGA) technology is described.

  17. International Olympiad on Astronomy and Astrophysics

    Science.gov (United States)

    Soonthornthum, B.; Kunjaya, C.

    2011-01-01

    The International Olympiad on Astronomy and Astrophysics, an annual astronomy and astrophysics competition for high school students, is described. Examples of problems and solutions from the competition are also given. (Contains 3 figures.)

  18. Fatal Candida septic shock during systemic chemotherapy in lung cancer patient receiving corticosteroid replacement therapy for hypopituitarism. A case report

    International Nuclear Information System (INIS)

    Invasive candidiasis has increased as nosocomial infection recently in cancer patients who receive systemic chemotherapy, and the timely risk assessment for developing such specific infection is crucial. Especially in those concomitantly with hypopituitarism, febrile neutropenia with candidiasis can cause severe stress and lead potentially to sudden fatal outcome when the temporal steroid coverage for the adrenal insufficiency is not fully administered. We report a 72-year-old male case diagnosed as non-small-cell lung cancer, Stage 3A. He had received a steroid replacement therapy for the prior history of hypophysectomy due to pituitary adenoma with hydrocortisone of 3.3 mg/day, equivalent to prednisolone of 0.8 mg/day. This very small dosage of steroid was hardly supposed to weaken his immune system, but rather potentially led to an inappropriate supplementation of his adrenal function, assuming that the serum sodium and chlorine levels decreased. On Day 6 of second cycle of chemotherapy with carboplatin and paclitaxel, he developed sudden febrile neutropenia, septic shock and ileus, leading to death. After his death, the venous blood culture on Day 7 detected Candida albicans. Autopsy findings showed a massive necrotizing enterocolitis with extensive Candida invasion into submucous tissue. In conclusion, this case may suggest that (1) immediate initiation of antifungal therapy soon after the careful risk assessment of Candida infection and (2) adequate administration of both basal steroid replacement therapy and temporal steroid coverage for febrile neutropenia might have improved his fatal outcome. (author)

  19. Astronomy Outreach for Large, Unique, and Unusual Audiences

    Science.gov (United States)

    Lubowich, Donald

    2015-08-01

    My successful outreach program venues include: outdoor concerts and festivals; the US National Mall; churches, synagogues, seminaries, or clergy conferences; the Ronald McDonald Houses of Long Island and Chicago; the Winthrop U. Hospital Children’s Medical Center the Fresh Air Fund summer camps (low-income and special needs); a Halloween star party (costumed kids look through telescopes); a Super Bowl Star Party (targeting women); Science Festivals (World, NYC; Princeton U.; the USA Science and Engineering Festival); and the NYC Columbus Day Parade. Information was also provided about local science museums, citizen science projects, astronomy educational sites, and astronomy clubs to encourage lifelong learning. In 2010 I created Astronomy Festival on the National Mall (co-sponsored by the White House Office of Science and Technology Policy) with the participation of astronomy clubs, scientific institutions and with Tyco Brahe, Johannes Kepler, and Caroline Herschel making guest appearances. My programs include solar, optical, and radio telescope observations, hands-on activities, a live image projection system; large outdoor posters and banners; videos; hands-on activities, and edible astronomy demonstrations.My NASA-funded Music and Astronomy Under the Stars (MAUS) program (60 events 2009 - 2013) reached 50,000 music lovers at local parks and the Central Park Jazz, Newport Folk, Ravinia, or Tanglewood Music Festivals with classical, folk, pop/rock, opera, Caribbean, or county-western concerts assisted by astronomy clubs. Yo-Yo-Ma, the Chicago and Boston Symphony Orchestras, Ravi Coltrane, Esperanza Spalding, Phish, Blood Sweat and Tears, Deep Purple, Tony Orlando, and Wilco performed at these events. MAUS reached underserved groups and attracted large crowds. Young kids participated in this family learning experience - often the first time they looked through a telescope. While education

  20. Astronomy and Shakespeare's Hamlet.

    Science.gov (United States)

    Usher, P. D.

    1996-05-01

    Payne-Gaposchkin and others have suggested that Hamlet shows evidence of the Bard's awareness of the astronomical revolutions of the sixteenth century. I summarize major arguments and note that the play's themes recur in modern astronomy teaching and research: (1) The play amounts to a redefinition of universal order and humankind's position in it. (2) There is interplay between appearance and reality. Such a contrast is commonplace wherever superficial celestial appearances obscure underlying physical realities, the nature of which emerge as the tale unfolds. (3) The outermost sphere of the Ptolemaic and Copernican models seems to encase humanity, who are liberated by the reality of Digges' model and the implications advanced by Bruno. Similarly the oppressiveness of the castle interior is relieved by the observing platform which enables the heavens to be viewed in their true light. (4) Hamlet could be bounded in a nut-shell and count himself a king of infinite space, were it not that he has bad dreams. These concern the subversiveness of the new doctrine, for Hamlet refers to the infinite universe only hypothetically and in the presence of Rosencrantz and Guildenstern, who are named for relatives of the Danish astronomer Brahe. (5) Hamlet, and Brahe and Bruno, have connections to the university at Wittenberg, as does the Copernican champion Rheticus. (6) Ways are needed to reveal both the truths of nature, and the true nature of Danish royalty. Those unaccustomed to science think that there is madness in Hamlet's method. In particular, `doubt' is advanced as a methodological principle of inquiry. (7) The impression of normalcy and propriety in the upper reaches of society is like the false impression of an encapsulating universe. In Hamlet this duality is dramatized tragically, whereas in King John (cf. BAAS 27, 1325, 1995) it is not; for by 1601 when the writing of Hamlet was probably completed, Shakespeare would have known of the martyrdom of Bruno the previous

  1. Astronomy 3.0 Style

    CERN Document Server

    Accomazzi, Alberto

    2010-01-01

    Over the next decade we will witness the development of a new infrastructure in support of data-intensive scientific research, which includes Astronomy. This new networked environment will offer both challenges and opportunities to our community and has the potential to transform the way data are described, curated and preserved. Based on the lessons learned during the development and management of the ADS, a case is made for adopting the emerging technologies and practices of the Semantic Web to support the way Astronomy research will be conducted. Examples of how small, incremental steps can, in the aggregate, make a significant difference in the provision and repurposing of astronomical data are provided.

  2. Statistical Challenges in Modern Astronomy

    CERN Document Server

    Feigelson, E D

    2003-01-01

    Despite centuries of close association, statistics and astronomy are surprisingly distant today. Most observational astronomical research relies on an inadequate toolbox of methodological tools. Yet the needs are substantial: astronomy encounters sophisticated problems involving sampling theory, survival analysis, multivariate classification and analysis, time series analysis, wavelet analysis, spatial point processes, nonlinear regression, bootstrap resampling and model selection. We review the recent resurgence of astrostatistical research, and outline new challenges raised by the emerging Virtual Observatory. Our essay ends with a list of research challenges and infrastructure for astrostatistics in the coming decade.

  3. Advances in astronomy and astrophysics

    CERN Document Server

    Kopal, Zdenek

    1963-01-01

    Advances in Astronomy and Astrophysics, Volume 2 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of six chapters and begins with a summary of observational record on twilight extensions of the Venus cusps. The next chapter deals with the common and related properties of binary stars, with emphasis on the evaluation of their cataclysmic variables. Cataclysmic variables refer to an object in one of three classes: dwarf nova, nova, or supernova. These topics are followed by discussions on the eclipse phenomena and the eclipses i

  4. Astronomy, space science and geopolitics

    Science.gov (United States)

    Courvoisier, Thierry J.-L.

    2011-06-01

    Astronomy has played a major part in the development of civilisations, not only through conceptual developments, but most importantly through the very practical gains obtained through the observation of Sun, Moon planets and stars. Space sciences, including astronomy, have also played a major rôle in the development of modern societies, as an engine for most subsequent space technology developments. Present trends tend to decrease the rôle of science in space development. This trend should be reversed to give modern ``societies'' their independence in space-related matters that permeate the lives of all inhabitants of the Earth.

  5. Astronomy, Space Science and Geopolitics

    CERN Document Server

    Courvoisier, Thierry J -L

    2010-01-01

    Astronomy has played a major part in the development of civilisations, not only through conceptual developments, but most importantly through the very practical gains obtained through the observation of Sun, Moon planets and stars. Space sciences, including astronomy, have also played a major role in the development of modern societies, as engine for most subsequent space technology developments. Present trends tend to decrease the role of science in space development. This trend should be reversed to give modern "societies" their independence in space related matters that permeate the lives of all inhabitants of the Earth.

  6. Advances in astronomy and astrophysics

    CERN Document Server

    Kopal, Zdenek

    1966-01-01

    Advances in Astronomy and Astrophysics, Volume 4 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of five chapters, and starts with a description of objective prism and its application in space observations. The next chapter deals with the possibilities of deriving reliable models of the figure, density distribution, and gravity field of the Moon based on data obtained through Earth-bound telescopes. These topics are followed by a discussion on the ideal partially relativistic, partially degenerate gas in an exact manner. A ch

  7. Spatial Thinking as the Dimension of Progress in an Astronomy Learning Progression

    Science.gov (United States)

    Plummer, Julia D.

    2014-01-01

    The big idea of "celestial motion", observational astronomy phenomena explained by the relative position and motion of objects in the solar system and beyond, is central to astronomy in primary and secondary education. In this paper, I argue that students' progress in developing productive, scientific explanations for this class of…

  8. Learning from the Starry Message: Using Galileo's "Sidereus Nuncius" in Introductory Astronomy Classes

    Science.gov (United States)

    Wiesner, Matthew P.

    2015-01-01

    Every introductory astronomy class encounters Galileo during the course as the first man to systematically study the sky with a telescope. Every Astronomy 101 student meets Galileo as one of the major catalysts behind the shift from the Ptolemaic to the Copernican system and as one of the great minds behind the scientific method. But most of the…

  9. Design and implementation of omni-directional light source and receiving system used in underwater wireless optical communication

    Science.gov (United States)

    Rao, Jionghui; Yao, Wenming; Chen, Nannan

    2013-08-01

    Underwater wireless optical communication is a communication mode which uses light as an information carrier and water as transmission medium. As a result of the inherent characteristics of the light waves, underwater wireless optical communication has the advantages of high transmission rate, good security, and strong anti-interference ability. It is suitable for high-speed, short-range communication between underwater mobile vehicles. Underwater optical wireless communication system designed in this paper is composed of the omni-directional communication light source and the receiving system. In the omni-directional communication light source, the laser beams with small divergence angle of 532nm wavelength produced by modulated laser are expanded through a combination refraction-reflection solid and then obtain more than 2π space divergence angle. The paper use TRACEPRO simulation tool to help design a combination solid composed of the lens, conical reflector and parabolic reflector, and test in the air and underwater, the result shows that the effect is fine. Unlike in the air, light attenuation is heavy in the water and a large range of variations in light intensity at different distances appear during underwater optical communication. In order to overcome this problem, the paper use a small photomultiplier as the detection device, design the receiving system using the automatic gain control technique. Underwater wireless optical communication system designed in this paper has the characteristics of small size, low power dissipation and the omni-directional communication function, it is suitable for application in the UUV, AUV, Swimmer Delivery Vehicle (SDV) and other underwater mobile platform, it realizes point-to-point communications and point-to-multipoint communications.

  10. Indian Astronomy: The Missing Link in Eurocentric History of Astronomy

    Science.gov (United States)

    Haque, Shirin; Sharma, Deva

    2016-01-01

    A comprehensive history of Astronomy should show in reasonable chronological order, the contributions from wherever they arise in the world, once they are reliably documented. However, the authors note that consistently, the extremely rich contributions from Ancient Indian scholars like Aryabatha and Bhramagupta are omitted in Eurocentric…

  11. Astronomy Education Project for Guangdong High Schools

    Indian Academy of Sciences (India)

    F. P. Pi; K. Y. Guan; J. Wang; H. G. Wang; Y. Liu; J. H. Fan

    2014-09-01

    Guangdong province is an active area in China for astronomy education and popularization. The current status and problems of astronomy education in high schools are reviewed. To tackle these problems, an astronomy education project for high school teachers and students was initiated by Guangzhou University in 2013. The purpose and key points of the projects are introduced in this paper.

  12. Blazing the Trail for Astronomy Education Research

    Science.gov (United States)

    Bailey, Janelle M.; Lombardi, Doug

    2015-01-01

    Education research has long considered student learning of topics in astronomy and the space sciences, but astronomy education research as a sub-field of discipline-based education research is relatively new. Driven by a growing interest among higher education astronomy educators in improving the general education, introductory science survey…

  13. The Challenges of Astronomy in Nigeria

    Science.gov (United States)

    Urama, J. O.

    Some Universities and Research Centres in Nigeria have, over the years, been extensively involved in both research and education in Astronomy and Space Sciences. However, they appear to be trading in an unwanted commodity as modern astronomy appears to continue to lack any serious public appreciation. This paper examines the challenges and problems confronting the development of Astronomy in the country.

  14. Autonomous Acoustic Receiver System

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Collects underwater acoustic data and oceanographic data. Data are recorded onboard an ocean buoy and can be telemetered to a remote ship or shore station...

  15. Teaching astronomy with dry erase whiteboards

    Science.gov (United States)

    Slater, Timothy F.

    2016-09-01

    In the quest to become a great astronomy teacher, one carefully considers what might be the best textbook, what might be the best homework collection and grading system, which classroom policies promote an active learning environment, and which teaching inclinations and strategies might work best with this year's students. But what about teaching equipment? As you are thinking about next year's teaching hardware needs, a surprisingly effective tool to consider adding to your cabinet that consistently encourages more active learning is a stack of small dry erase whiteboards.

  16. Astronomical problems an introductory course in astronomy

    CERN Document Server

    Vorontsov-Vel'Yaminov, B A

    1969-01-01

    Astronomical Problems: An Introductory Course in Astronomy covers astronomical problems, together with a summary of the theory and the formula to be exercised. The book discusses the types of problems solved with the help of the celestial globe and how to solve astronomical problems. The text tackles problems on interpolation, the celestial sphere, systems of celestial coordinates, and culmination. Problems about the rising and setting of a heavenly body, precession, planetary movement, and parallax and aberration are also considered. The book presents problems about refraction, the apparent m

  17. Physics and astronomy of the Moon

    CERN Document Server

    Kopal, Zdenek

    2013-01-01

    Physics and Astronomy of the Moon focuses on the application of principles of physics in the study of the moon, including perturbations, equations, light scattering, and photometry. The selection first offers information on the motion of the moon in space and libration of the moon. Topics include Hill's equations of motion, non-solar perturbations, improved lunar ephemeris, optical and physical libration of the moon, and adjustment of heliometric observations of the moon's libration. The text then elaborates on the dynamics of the earth-moon system, photometry of the moon, and polarization of

  18. Music of the heavens Kepler's harmonic astronomy

    CERN Document Server

    Stephenson, Bruce

    2014-01-01

    Valued today for its development of the third law of planetary motion, Harmonice mundi (1619) was intended by Kepler to expand on ancient efforts to discern a Creator's plan for the planetary system--an arrangement thought to be based on harmonic relationships. Challenging critics who characterize Kepler's theories of harmonic astronomy as ""mystical,"" Bruce Stephenson offers the first thorough technical analysis of the music the astronomer thought the heavens made, and the logic that led him to find musical patterns in his data. In so doing, Stephenson illuminates crucial aspects of Kepler'

  19. Development of a high temperature solar receiver for high-efficient thermionic conversion systems; Fukugo netsuden henkan system yo chokoon taiyo junetsuki no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Umeoka, T.; Naito, H.; Yugami, H.; Arashi, H. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1996-10-27

    For thermionic conversion systems (TIC) using concentrated sunlight as heat source, the newly developed solar receiver was tested. Concentrated sunlight aims at the inner surface of the cavity type solar receiver. The emitter of TIC installed in the rear of the solar receiver is uniformly heated over 1700K by thermal radiation from the rear of the solar receiver, emitting thermion. Electric power is generated by collecting the thermion by collector. Mo is used as emitter material, however, because of poor heat absorption of Mo, high-absorptive TiC is used for heat absorption surface to heat Mo by thermal conduction from high-temperature TiC. Functionally gradient material (FGM) with an intermediate layer of gradient TiC/Mo ratios between TiC and Mo is used as emitter material. The emitter is thus uniformly heated at high temperatures of 1723{plus_minus}12K. As a result, the developed solar receiver is applicable to heat the emitter of TIC. Heat flux measurement at the graphite cavity clarified that cavity temperature of as high as 1780K and heat flow of 50W/cm{sup 2} are obtained at 4.7kW in input. 6 figs.

  20. DSP-Enabled Radio Astronomy: Towards IIIZW35 Reconquest

    Directory of Open Access Journals (Sweden)

    Alain Lecacheux

    2005-09-01

    Full Text Available In radio astronomy, the radio spectrum is used to detect weak emission from celestial sources. By spectral averaging, observation noise is reduced and weak sources can be detected. However, more and more observations are polluted by man-made radio frequency interferences (RFI. The impact of these RFIs on power spectral measurement ranges from total saturation to subtle distortions of the data. To some extent, elimination of artefacts can be achieved by blanking polluted channels in real time. With this aim in view, a complete real-time digital system has been implemented on a set of FPGA and DSP. The current functionalities of the digital system have high dynamic range of 70 dB, bandwidth selection facilities ranging from 875 kHz to 14 MHz, high spectral resolution through a polyphase filter bank with up to 8192 channels with 49 152 coefficients and real-time time-frequency blanking with a robust threshold detector. This receiver has been used to reobserve the IIIWZ35 astronomical source which has been scrambled by a strong satellite RFI for several years.

  1. Integrating Astronomy with Elementary Non-Science Curricula

    Science.gov (United States)

    Bobrowsky, M.

    1996-05-01

    A workshop was developed for elementary school teachers to enhance students' understanding of astronomy during the formative years of elementary school by incorporating astronomy into various non-science curricula. Educational material was compiled for teachers and students and training was provided for the teachers in the form of a workshop where both information and hands-on activities were disseminated. In addition, we are producing a video tape from the workshop which will be available not only to those who attended the workshop but to other teachers as well. A useful ``multiplier effect" in this project came from our focus on a school that was hosting a group of teachers in training. After these teachers receive certification, they will end up working in all different schools, thereby reaching large numbers of students for many years. The non-scientific subjects that we will connect to astronomy include history, music, art, language arts, social studies, and mathematics, as well as incidental subjects such as health and public safety. Support for this work was provided by NASA through grant number ED90024.01-94A from the Space Telescope Science Institute which is operated by the Association of Universities for Research in Astronomy Inc. under NASA Contract NAS5-26555.

  2. NASA Stratospheric Observatory For Infrared Astronomy (SOFIA) Airborne Astronomy Ambassador Program Evaluation Results To Date

    Science.gov (United States)

    Harman, Pamela K.; Backman, Dana E.; Clark, Coral

    2015-08-01

    SOFIA is an airborne observatory, capable of making observations that are impossible for even the largest and highest ground-based telescopes, and inspires instrumention development.SOFIA is an 80% - 20% partnership of NASA and the German Aerospace Center (DLR), consisting of a modified Boeing 747SP aircraft carrying a diameter of 2.5 meters (100 inches) reflecting telescope. The SOFIA aircraft is based at NASA Armstrong Flight Research Center, Building 703, in Palmdale, California. The Science Program Office and Outreach Office is located at NASA Ames Research center. SOFIA is one of the programs in NASA's Science Mission Directorate, Astrophysics Division.SOFIA will be used to study many different kinds of astronomical objects and phenomena, including star birth and death, formation of new solar systems, identification of complex molecules in space, planets, comets and asteroids in our solar system, nebulae and dust in galaxies, and ecosystems of galaxies.Airborne Astronomy Ambassador Program:The SOFIA Education and Communications program exploits the unique attributes of airborne astronomy to contribute to national goals for the reform of science, technology, engineering, and math (STEM) education, and to the elevation of public scientific and technical literacy.SOFIA’s Airborne Astronomy Ambassadors (AAA) effort is a professional development program aspiring to improve teaching, inspire students, and inform the community. To date, 55 educators from 21 states; in three cohorts, Cycles 0, 1 and 2; have completed their astronomy professional development and their SOFIA science flight experience. Cycle 3 cohort of 28 educators will be completing their flight experience this fall. Evaluation has confirmed the program’s positive impact on the teacher participants, on their students, and in their communities. Teachers have incorporated content knowledge and specific components of their experience into their curricula, and have given hundreds of presentations and

  3. Design of high-order HTS dual-band bandpass filters with receiver subsystem for future mobile communication systems

    Science.gov (United States)

    Sekiya, N.

    2016-08-01

    We have developed two high-order high-temperature superconducting (HTS) dual-band bandpass filters (BPFs) with a receiver subsystem for future mobile communication systems. They feature stub-loaded hair-pin resonators with two types of microstrip lines between them. One has a six-pole design, and the other has an eight-pole design. Both were designed to operate at 2.15 GHz with a 43-MHz (2%) bandwidth for the lower passband and at 3.50 GHz with a 70-MHz (2%) bandwidth for the upper one. They were fabricated using YBa2Cu3Oy thin film on a CeO2-bufferd r-Al2O3 substrate. The measured results for both filters agree well with the simulated ones. The HTS dual-band BPF receiver subsystem uses a pulse tube cryocooler and a wideband low noise amplifier (LNA). We measured the frequency response of the six-pole dual-band BPF with and without a wideband LNA with a gain of 10 dB. The measured return losses were close.

  4. Exchange of astronomy teaching experiences

    Science.gov (United States)

    Ros, Rosa M.

    The Working Group of the European Association for Astronomy Education responsible for Teacher Training organises an annual Summer School for teachers under expert guidance. For a week the teachers participating can exchange experiences, increase their knowledge and discuss different ideas and perspectives. In general, the instructors are professional astronomers, professors and teachers from different countries. The papers presented offer very practical activities, paying special attention to didactic aspects, and take the form of general lectures to all 40 participants and workshops to reduced groups of 20 participants. There are also day and night observations, without expensive equipment or complicated procedures, that are easy to set up and based on topics that it is possible to use in the classroom. The Summer Schools promote a scientific astronomical education at all levels of astronomy teaching, reinforce the link between professional astronomers and teachers with experience of teaching astronomy, allow debates among the participants on their pedagogical activities already carried out in their own classroom and help them to organise activities outside it. Astronomy teachers need special training, access to specific research, to new educational materials and methods and the opportunity to exchange experiences. All these things are provided by the Summer School.

  5. Astronomy Education Challenges in Egypt

    Science.gov (United States)

    El Fady Beshara Morcos, Abd

    2015-08-01

    One of the major challenges in Egypt is the quality of education. Egypt has made significant progress towards achieving the Education for All and the Millennium Development Goals (MDGs). Many associations and committees as education reform program and education support programs did high efforts in supporting scientific thinking through the scientific clubs. The current state of astronomical education in Egypt has been developed. Astronomy became a part in both science and geography courses of primary, preparatory and secondary stages. Nowadays the Egyptian National Committee for Astronomy, put on its shoulders the responsibility of revising of astronomy parts in the education courses, beside preparation of some training programs for teachers of different stages of educations, in collaboration with ministry of education. General lectures program has been prepared and started in public places , schools and universities. Many TV and Radio programs aiming to spread astronomical culture were presented. In the university stage new astronomy departments are established and astrophysics courses are imbedded in physics courses even in some private universities.

  6. Astronomy and Astrophysics in India

    Science.gov (United States)

    Narlikar, J.; Murdin, P.

    2001-07-01

    The growth in astronomy and astrophysics (A&A) in India has been mostly since the country achieved independence in 1947. The present work is carried out in a few select research institutes and in some university departments. The Astronomical Society of India has around 300 working A&A scientists as members, with another 50-60 graduate students....

  7. Service Learning in Introductory Astronomy

    Science.gov (United States)

    Orleski, Michael

    2013-01-01

    Service learning is a method of instruction where the students in a course use the course's content in a service project. The service is included as a portion of the students' course grades. During the fall semester 2010, service learning was incorporated into the Introduction to Astronomy course at Misericordia University. The class had…

  8. Neutrino astronomy: Present and future

    Indian Academy of Sciences (India)

    Thomas McCauley

    2006-10-01

    I briefly review the present and future status of the burgeoning field of neutrino astronomy. I outline the astrophysics and particle physics goals, design, and performance of the various current and proposed neutrino telescopes. Also described are present results and future expectations.

  9. The Impact of User Effects on the Performance of Dual Receive Antenna Diversity Systems in Flat Rayleigh Fading Channels

    Directory of Open Access Journals (Sweden)

    P. Liu

    2014-04-01

    Full Text Available In this paper we study the impact of user effects on the performance of receive antenna diversity systems in flat Rayleigh fading channels. Three diversity combining techniques are compared: maximal ratio combining (MRC, equal gain combining (EGC, and selection combining (SC. User effects are considered in two scenarios: 1 body loss (the reduction of effective antenna gain due to user effects on a single antenna, and 2 equal body loss on both antennas. The system performance is assessed in terms of mean SNR, link reliability, bit error rate of BPSK, diversity order and ergodic capacity. Our results show that body loss on a single antenna has limited (bounded impact on system performance. In comparison, body loss on both antennas has unlimited (unbounded impact and can severely degrade system performance. Our results also show that with increasing body loss on a single antenna the performance of EGC drops faster than that of MRC and SC. When body loss on a single antenna is larger than a certain level, EGC is not a “sub-optimal” method anymore and has worse performance than SC.

  10. Waste Receiving and Processing Facility PMS Test Report/DMS-Y2K/System Security DMS (Data Management System)

    International Nuclear Information System (INIS)

    Test Plan HNF-4351 defines testing requirements for installation of a new server in the WRAP Facility. This documents shows the results of the test reports on the DMS-Y2K and DMS-F81 (Security) systems

  11. Schiaparelli and the dawn of astronomy

    Science.gov (United States)

    Antonello, E.

    Schiaparelli is remembered by astronomers and scholars interested in ancient astronomy in particular for his fundamental contributions to the understanding of ancient Greek astronomy and for his pioneer work on babylonian astronomy. In the present paper we will highlight some of his studies and ideas about: a) the origins and the primitive astronomy in the context of the european archaeology and anthropology researches, b) the problems in the analysis of a cuneiform tablet, and c) the interpretation of the astronomical content of a verse in the Old Testament, with an interesting implication for the present day researches in cultural astronomy and archaeoastronomy.

  12. Training in Astronomy for Physics Students

    Indian Academy of Sciences (India)

    J. H. Fan

    2014-09-01

    In this paper, we describe what we have done with regard to astronomy training for physics students. More and more students are interested in astronomy, they spend their summer holidays and spare time in observations and studying the observation data. Some students are familiar with using the telescope for observations, dealing with absorption line features achieved from the observations. Astronomy was selected as the key subject in Guangzhou city and Guangdong province, the laboratory for astronomy science and technology was selected as the key laboratory of Guangzhou city and that for the education department of Guangdong Province. We also provide a master degree programme for astronomy.

  13. Real-Time Point Positioning Performance Evaluation of Single-Frequency Receivers Using NASA's Global Differential GPS System

    Science.gov (United States)

    Muellerschoen, Ronald J.; Iijima, Byron; Meyer, Robert; Bar-Sever, Yoaz; Accad, Elie

    2004-01-01

    This paper evaluates the performance of a single-frequency receiver using the 1-Hz differential corrections as provided by NASA's global differential GPS system. While the dual-frequency user has the ability to eliminate the ionosphere error by taking a linear combination of observables, the single-frequency user must remove or calibrate this error by other means. To remove the ionosphere error we take advantage of the fact that the magnitude of the group delay in range observable and the carrier phase advance have the same magnitude but are opposite in sign. A way to calibrate this error is to use a real-time database of grid points computed by JPL's RTI (Real-Time Ionosphere) software. In both cases we evaluate the positional accuracy of a kinematic carrier phase based point positioning method on a global extent.

  14. Response of Global Navigation Satellite System receivers to known shaking between 0.2 and 20 Hertz

    Science.gov (United States)

    Langbein, John; Evans, John R.; Blume, Fredrick; Johanson, Ingrid

    2014-01-01

    Over the past decade, several technological advances have allowed Global Navigation Satellite Systems (GNSS) receivers to have the capability to record displacements at high frequencies, with sampling rates approaching 100 samples per second (sps). In addition, communication and computer hardware and software have allowed various institutions, including the U.S. Geological Survey (USGS), to retrieve, process, and display position changes recorded by a network of GNSS sites with small, less than 1-s delays between the time that the GNSS receiver records signals from a constellation of satellites and the time that the position is estimated (a method known as “real-time”). These improvements in hardware and software have allowed the USGS to process GNSS (or a subset of the GNSS, the Global Positioning System, GPS) data in real-time at 1 sps with the goal of determining displacements from earthquakes and volcanoes in real-time. However, the current set of GNSS equipment can record at rates of 100 sps, which allows the possibility of using this equipment to record earthquake displacements over the full range of frequencies that typically are recorded by acceleration and velocity transducers. The advantage of using GNSS to record earthquakes is that the displacement, rather than acceleration or velocity, is recorded, and for large earthquakes, the GNSS sensor stays on scale and will not distort the observations due to clipping of the signal at its highest amplitude. The direct observation of displacement is advantageous in estimating the size and spatial extent of the earthquake rupture. Otherwise, when using velocity or acceleration sensors, the displacements are determined by numerical integration of the observations, which can introduce significant uncertainty in the estimated displacements. However, GNSS technology can, at best, resolve displacements of a few millimeters, and for most earthquakes, their displacements are less than 1 mm. Consequently, to be useful

  15. Increasing the Number of Underrepresented Minorities in Astronomy: Executive Summary

    CERN Document Server

    Norman, Dara; NSHP,; Agueros, Marcel; Anderson, Scott F; Baker, Andrew; Burgasser, Adam; Cruz, Kelle; Ernst, David J; Gawiser, Eric; Krishnamurthi, Anita; Lee, Hyun-chul; Mighell, Kenneth; McGruder, Charles; Sakimoto, Philip J; Sheth, Kartik; Soderblom, Dave; Strauss, Michael; Walter, Donald; West, Andrew; Agol, UW Pre-Map staff - Eric; Murphy, Jeremiah; Garner, Sarah; Bellovary, Jill; Schmidt, Sarah; Cowan, Nick; Gogarten, Stephanie; Stilp, Adrienne; Christensen, Charlotte; Hilton, Eric; Haggard, Daryl; Rosenfield, Sarah Loebman Phil; Munshi, Ferah

    2009-01-01

    Promoting racial and ethnic diversity is critically important to the future success and growth of the field of astronomy. The raw ability, drive and interest required to excel in the field is distributed without regard to race, gender, or socioeconomic background. By not actively promoting diversity in our field we risk losing talented people to other professions (or losing them entirely), which means that there will be astronomical discoveries that simply won't get made. There is demonstrated evidence that STEM fields benefit from diverse perspectives on problems that require more complex thought processes. This is especially relevant to a field like astronomy where more and more work is being done collaboratively. The lack of notable growth in African American, Hispanic, and Native American representation in astronomy indicates that the 'pipeline' for these individuals is systemically leaky at critical junctures. Substantially more effort must be directed toward improving the educational and career developm...

  16. Why Astronomy Should BE Taught in Schools - a Resolution

    Science.gov (United States)

    Stavinschi, Magda

    Perhaps more than other post-Communist countries Romania underwent a dramatic change after 1989. One of the most sharp problems remains the change of mentality and implicitly education of youngsters. Astronomy has a particularly important role in this context especially now. Unfortunately it does not belong to curricula anymore. Its reintroduction as well as a new system of scientific education in agreement with the knowledge and technology of the 21th century is compulsory in both Romania and other European countries. This international campaign and new ways for implementing astronomy in education can be carried out after the emission of an IAU resolution (see Newsletter 55 October 2001). The same problems specific not only to Romania but to Europe too will be tackled in view of a special session ""Astronomy education in Europe"" at JENAM 2003.

  17. Digital Data Preservation for Scholarly Publications in Astronomy

    Directory of Open Access Journals (Sweden)

    Sayeed Choudhury

    2007-12-01

    Full Text Available Astronomy is similar to other scientific disciplines in that scholarly publication relies on the presentation and interpretation of data. But although astronomy now has archives for its primary research telescopes and associated surveys, the highly processed data that is presented in the peer-reviewed journals and is the basis for final analysis and interpretation is generally not archived and has no permanent repository. We have initiated a project whose goal is to implement an end-to-end prototype system which, through a partnership of a professional society, that society’s scholarly publications/publishers, research libraries, and an information technology substrate provided by the Virtual Observatory, will capture high-level digital data as part of the publication process and establish a distributed network of curated, permanent data repositories. The data in this network will be accessible through the research journals, astronomy data centers, and Virtual Observatory data discovery portals.

  18. A Great Moment for Astronomy

    Science.gov (United States)

    1998-05-01

    VLT First Light Successfully Achieved The European Southern Observatory announces that First Light has been achieved with the first VLT 8.2-m Unit Telescope at the Paranal Observatory. Scientifically useful images have been obtained as scheduled, on May 25 - 26, 1998. A first analysis of these images convincingly demonstrates the exceptional potential of the ESO Very Large Telescope. Just one month after the installation and provisional adjustment of the optics, the performance of this giant telescope meets or surpasses the design goals, in particular as concerns the achievable image quality. Exposures lasting up to 10 minutes confirm that the tracking, crucial for following the diurnal rotation of the sky, is very accurate and stable. It appears that the concept developed by ESO for the construction of the VLT, namely an actively controlled, single thin mirror, yields a very superior performance. In fact, the angular resolution achieved even at this early stage is unequalled by any large ground-based telescope . The combination of large area and fine angular resolution will ultimately result in a sensitivity for point sources (e.g. stars), which is superior to any yet achieved by existing telescopes on Earth. The present series of images demonstrate these qualities and include some impressive first views with Europe's new giant telescope. After further optimization of the optical, mechanical and electronic systems, and with increasing operational streamlining, this telescope will be able to deliver unique astronomical data of the highest quality. The commissioning and science verification phases of the complex facility including instruments will last until April 1, 1999, at which time the first visiting astronomers will be received. The full significance of this achievement for astronomy will take time to assess. For Europe, this is a triumph of the collaboration between nations, institutions and industries. For the first time in almost a century, European

  19. Digital Receiver-based Electronic Intelligence System Configuration for the Detection and Identification of Intrapulse Modulated Radar Signals

    Directory of Open Access Journals (Sweden)

    A. K. Singh

    2014-03-01

    Full Text Available An optimum electronic intelligence system configuration incorporating the state of the art technologies and achieving the highest parameter accuracies while processing the complex intrapulse modulated radar signals is presented in this paper. The system is based on the quad digital receiver, a state of the art single board solution for the detection and analysis of modern radar signals. The system consists of base line interferometry  configuration for high accuracy direction finding measurement with sector selection based on amplitude direction finding technique. Advanced signal processing algorithms with time frequency analysis are implemented in real time in field programmable gate array to extract all the basic as well as advanced parameters of frequency and phase modulations such as chirp, barker, and poly-phase (Frank, P1-P4 codes in addition to the pulse and continuous wave signals. The intercepted intrapulse modulated signal parameters have been extracted with very high accuracy and sensitivity.Defence Science Journal, 2014, 64(2, pp. 152-158. DOI: http://dx.doi.org/10.14429/dsj.64.5091

  20. 应用于射电天文数字终端的网络传输系统的设计%The Design of Network Transmission System Applied in Radio Astronomy Digital Equipment

    Institute of Scientific and Technical Information of China (English)

    于威; 张秀忠; 吴亚军; 郭绍光; 甘江英

    2012-01-01

    射电天文数字终端对各类天体发出的无线电信号进行处理后,需把数据传送到数据记录设备存储起来,以进行更进一步的分析和处理.为了满足数据传输需要,本文设计了一种千兆网网络传输系统把射电天文数字终端产生的数据传送到数据记录设备,测试结果表明,该网络系统在数据速率低于640 Mb/s的情况下工作良好,数据丢失率非常低.目前该系统己初步应用于DBBC、连续谱终端等射电天数字终端中.%When radio signal was processed by radio astronomy digital equipment, we need to transmit it to data record equipment, so that we can undertake further analysis and processing. In order to satisfy the requirement of data transmission, in this paper we designed a network transmission system based on Gigabit Ethernet. The test result showed that this system worked well when the data rate was lower than 640 Mb/s. Now this system has been applied in some radio astronomy equipments such as DBBC, continuous spectrum instrument and so on.