Science.gov

Sample records for digital safety channel

  1. Environmental testing of an experimental digital safety channel

    SciTech Connect

    Korsah, K.; Tanaka, T.J.; Wilson, T.L. Jr.; Wood, R.T.

    1996-09-01

    This document presents the results of environmental stress tests performed on an experimental digital safety channel (EDSC) assembled at the Oak Ridge National Laboratory (ORNL) as part of the NRC-sponsored Qualification of Advanced Instrumentation and Controls (W) System program. The objective of this study is to investigate failure modes and vulnerabilities of microprocessor-based technologies when subjected to environmental stressors. The study contributes to the technical basis for environmental qualification of safety-related digital I&C systems. The EDSC employs technologies and digital subsystems representative of those proposed for use in advanced light-water reactors (ALWRs) or for retrofits in existing plants. Subsystems include computers, electrical and optical serial communication links, fiber-optic network links, analog-to-digital and digital-to-analog converters, and multiplexers. The EDSC was subjected to selected stressors that are a potential risk to digital equipment in a mild environment. The selected stressors were electromagnetic and radio-frequency interference (EMYRFI), temperature, humidity, and smoke exposure. The stressors were applied over ranges that were considerably higher than what the channel is likely to experience in a normal nuclear power plant environment. Ranges of stress were selected at a sufficiently high level to induce errors so that failure modes that are characteristic of the technologies employed could be identified.

  2. Environmental testing of a prototypic digital safety channel, phase I: System design and test methodology

    SciTech Connect

    Korsah, K.; Turner, G.W.; Mullens, J.A.

    1995-02-01

    A microprocessor-based reactor trip channel has been assembled for environmental testing under an Instrumentation and Control (I&C) Qualification Program sponsored by the U.S. Nuclear Regulatory Commission. The goal of this program is to establish the technical basis for the qualification of advanced I&C systems. The trip channel implemented for this study employs technologies and digital subsystems representative of those proposed for use in some advanced light-water reactors (ALNWS) such as the Simplified Boiling Water Reactor (SBNW) and AP600. It is expected that these tests will reveal any potential system vulnerabilities for technologies representative of those proposed for use in ALNWS. The experimental channel will be purposely stressed considerably beyond what it is likely to experience in a normal nuclear power plant environment, so that the tests can uncover the worst-case failure modes (i.e., failures that are likely to prevent an entire trip system from performing its safety function when required to do so). Based on information obtained from this study, it may be possible to recommend tests that are likely to indicate the presence of such failure mechanisms. Such recommendations would be helpful in augmenting current qualification guidelines.

  3. Environmental testing of a prototypic digital safety channel, Phase I: System design and test methodology

    SciTech Connect

    Korsah, K.; Turner, G.W.; Mullens, J.A.

    1995-04-01

    A microprocessor-based reactor trip channel has been assembled for environmental testing under an Instrumentation and Control (I&C) Qualification Program sponsored by the US Nuclear Regulatory Commission. The goal of this program is to establish the technical basis and acceptance criteria for the qualification of advanced I&C systems. The trip channel implemented for this study employs technologies and digital subsystems representative of those proposed for use in some advanced light-water reactors (ALWRs) such as the Simplified Boiling Water Reactor (SBWR). It is expected that these tests will reveal any potential system vulnerabilities for technologies representative of those proposed for use in ALWRs. The experimental channel will be purposely stressed considerably beyond what it is likely to experience in a normal nuclear power plant environment, so that the tests can uncover the worst-case failure modes (i.e., failures that are likely to prevent an entire trip system from performing its safety function when required to do so). Based on information obtained from this study, it may be possible to recommend tests that are likely to indicate the presence of such failure mechanisms. Such recommendations would be helpful in augmenting current qualification guidelines.

  4. A multi-channel waveform digitizer system

    SciTech Connect

    Bieser, F.; Muller, W.F.J. )

    1990-04-01

    The authors report on the design and performance of a multichannel waveform digitizer system for use with the Multiple Sample Ionization Chamber (MUSIC) Detector at the Bevalac. 128 channels of 20 MHz Flash ADC plus 256 word deep memory are housed in a single crate. Digital thresholds and hit pattern logic facilitate zero suppression during readout which is performed over a standard VME bus.

  5. Digital transmission of HDTV on satellite channels

    NASA Astrophysics Data System (ADS)

    Cominetti, Mario; Morello, Alberto; Castellani, Valentino; Visintin, Monica; Casoria, Atanasio; Losquadro, Giacinto; Puccio, Antonio

    1991-04-01

    The perspectives for digital HDTV on satellite channels are investigated in light of the recent progress on bit-rate reduction algorithms and on modulation and channel coding methods. A design example of a complete satellite chain at 30/20 GHz shows the feasibility of a 140 Mbit/s HDTV transmission system based on the described methods.

  6. Dynamic Digital Channelizer Based on Spectrum Sensing.

    PubMed

    Hu, Junpeng; Zuo, Zhen; Huang, Zhiping; Dong, Zhi

    2015-01-01

    The ability to efficiently channelize a received signal with dynamic sub-channel bandwidths is a key requirement of software defined radio (SDR) systems. The digital channelizer, which is used to split the received signal into a number of sub-channels, plays an important role in SDR systems. In this paper, a design of dynamic digital channelizer is presented. The proposed method is novel in that it employs a cosine modulated filter bank (CMFB) to divide the received signal into multiple frequency sub-bands and a spectrum sensing technique, which is mostly used in cognitive radio, is introduced to detect the presence of signal of each sub-band. The method of spectrum sensing is carried out based on the eigenvalues of covariance matrix of received signal. The ratio of maximum-minimum eigenvalue of each sub-band is vulnerable to noise fluctuation. This paper suggests an optimized method to calculate the ratio of maximum-minimum eigenvalue. The simulation results imply that the design of digital channelizer can effectively separate the received signal with dynamically changeable sub-channel signals. PMID:26308210

  7. Concurrent signal combining and channel estimation in digital communications

    DOEpatents

    Ormesher, Richard C.; Mason, John J.

    2011-08-30

    In the reception of digital information transmitted on a communication channel, a characteristic exhibited by the communication channel during transmission of the digital information is estimated based on a communication signal that represents the digital information and has been received via the communication channel. Concurrently with the estimating, the communication signal is used to decide what digital information was transmitted.

  8. 47 CFR 74.786 - Digital channel assignments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.786 Digital channel assignments. (a) An applicant for a new low... same TV channel and the adjacent channel within whose licensed geographic boundaries the digital...

  9. 47 CFR 74.786 - Digital channel assignments.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.786 Digital channel assignments. (a) An applicant for a new low... same TV channel and the adjacent channel within whose licensed geographic boundaries the digital...

  10. 47 CFR 74.786 - Digital channel assignments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.786 Digital channel assignments. (a) An applicant for a new low... same TV channel and the adjacent channel within whose licensed geographic boundaries the digital...

  11. 47 CFR 74.786 - Digital channel assignments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.786 Digital channel assignments. (a) An applicant for a new low... same TV channel and the adjacent channel within whose licensed geographic boundaries the digital...

  12. Channel coding for digital HDTV terrestrial broadcasting

    NASA Technical Reports Server (NTRS)

    Beakley, Guy W.

    1991-01-01

    The Federal Communications Commission of the United States has ruled that high-definition television (HDTV) will occupy no more than 6 MHz of the VHF and UHF bands now used for conventional TV. In order to transmit the HDTV signal in 6 MHz, the four United States digital HDTV proponents, the DigiCipher, DSC-HDTV, ADTV, and ATVA-P systems, are reducing the video data rate of HDTV to 15-17 Mb/s, a compression ratio of approximately 60-70 times. The high compression dictates that channel coding be used to avoid block errors and multiframe error propagation. High efficiency in channel utilization required by the 6-MHz limitation means that the channel must be properly equalized and that the multipath and interfering signals must be severely limited. The channel coding techniques used for error reduction include data interleaving, error detection and replacement, and error correction at different levels of protection for bits and blocks of unequal importance.

  13. Digital Channel Simulator Developed and Tested

    NASA Technical Reports Server (NTRS)

    Bizon, Thomas P.

    2000-01-01

    The Digital Channel Simulator (DCS) is a real-time test set developed in-house by the NASA Glenn Research Center at Lewis Field that simulates the characteristics of the modulator, demodulator, and transmission medium in a typical communications system to enable controlled laboratory testing of codec pairs. The DCS can support data rates up to 100 megasymbols per second (Msymbols/sec) with symbol sizes up to 10 bits and is compatible with both TTL (transistor transistor logic) and ECL (emitter coupled logic) interfaces. Because of its use of digital integrated circuits (IC's), the DCS offers the user accurate and repeatable testing while maintaining a simple reconfiguration of the modulation scheme and noise characteristics. The PC-based graphical user interface (GUI) assures user friendly operation for configuring, controlling, and monitoring the DCS and system during tests. In a typical communications system, the modulator places a symbol in constellation space and puts it on a carrier to be sent to the demodulator. Because of noise on the channel, the I and Q position in constellation space cannot be recovered exactly, and the received coordinates shift. To mimic this process in the laboratory, the DCS uses a mapper to place the symbol in constellation space. It simulates the shift in coordinates by digitally adding "noise" to the I and Q values. The mapper and noise source are implemented in lookup tables. Modulation schemes and noise characteristics are set by the values loaded in these tables. The mapper also has a pass-through mode to facilitate modulator testing, allowing noise to be added to 8-bit I and Q values of modulated data without a second mapping. To achieve high symbol rates, eight processing circuits are placed in parallel between an ECL demultiplexer and multiplexer. A graphical user interface was developed to calculate, load, and verify the values for the lookup tables. This interface can also be used to debug and verify proper operation of the

  14. Digital correlator for the portable channel prober measurement instrument

    NASA Astrophysics Data System (ADS)

    Peo, George E., Jr.

    1987-12-01

    This document describes a Digital Correlator for the Portable Channel Prober Measurement Instrument being developed by the Naval Research Laboratory for use in experiments designed to characterize high frequency (HF) radio channels. This Digital Correlator is a digital signal processor designed and constructed by Stow Computer, 111 old Bolton Road, Stow, MA 01775, (617/508) 897-6838. Two Digital Correlators are integrated into the existing Digital Pre-processor to make a Portable Wideband HF Channel Analyzer. The Portable Wideband HF Channel Analyzer will be located at the receiving site of the channel probing experiment and is situated between the coherent radio receiver and the microcomputer used for data recording and analysis. The Portable Wideband HF Channel Analyzer computes the delay power spectrum of the received waveform. The in-phase and quadrature outputs of the receiver are sampled and converted to digital values by the Analog to Digital Converter, integrated by the Integrator, and correlated with a stored replica of the transmitted waveform by two Digital Correlators. The resulting tap gains are then read by the system microcomputer using the microcomputer interface.

  15. 75 FR 12688 - Safety Zone; Gallants Channel, Beaufort, NC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    ... establishes a temporary safety zone to protect the public from bridge maintenance operations. An environmental... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Gallants Channel, Beaufort, NC AGENCY... safety zone on the waters of Gallants Channel at Beaufort, North Carolina. The safety zone is...

  16. [Information safety test of digital medical device].

    PubMed

    Liu, Jiong

    2014-07-01

    According to the background of the age of big data, the medical devices are informatized, we analyze the safety and efficiency for the information and data of digital medical devices or medical systems, also discussed some test methods. Lack of a suitable standard system of digital medical devices is a big problem both for domain standard and international standard. GB25000.51 is too ambiguous and free for testing, also not very operational. So this paper suggested some test advices and some prospective method. These test methods are helpful for finding the problem and performing the standards. What's more, these methods are famous in the world and used widely in the 3C region but just start in the medical region, which can promote the development of the medical devices. PMID:25330611

  17. DESDynI Quad First Stage Processor - A Four Channel Digitizer and Digital Beam Forming Processor

    NASA Technical Reports Server (NTRS)

    Chuang, Chung-Lun; Shaffer, Scott; Smythe, Robert; Niamsuwan, Noppasin; Li, Samuel; Liao, Eric; Lim, Chester; Morfopolous, Arin; Veilleux, Louise

    2013-01-01

    The proposed Deformation, Eco-Systems, and Dynamics of Ice Radar (DESDynI-R) L-band SAR instrument employs multiple digital channels to optimize resolution while keeping a large swath on a single pass. High-speed digitization with very fine synchronization and digital beam forming are necessary in order to facilitate this new technique. The Quad First Stage Processor (qFSP) was developed to achieve both the processing performance as well as the digitizing fidelity in order to accomplish this sweeping SAR technique. The qFSP utilizes high precision and high-speed analog to digital converters (ADCs), each with a finely adjustable clock distribution network to digitize the channels at the fidelity necessary to allow for digital beam forming. The Xilinx produced FX130T Virtex 5 part handles the processing to digitally calibrate each channel as well as filter and beam form the receive signals. Demonstrating the digital processing required for digital beam forming and digital calibration is instrumental to the viability of the proposed DESDynI instrument. The qFSP development brings this implementation to Technology Readiness Level (TRL) 6. This paper will detail the design and development of the prototype qFSP as well as the preliminary results from hardware tests.

  18. An Efficient, Highly Flexible Multi-Channel Digital Downconverter Architecture

    NASA Technical Reports Server (NTRS)

    Goodhart, Charles E.; Soriano, Melissa A.; Navarro, Robert; Trinh, Joseph T.; Sigman, Elliott H.

    2013-01-01

    In this innovation, a digital downconverter has been created that produces a large (16 or greater) number of output channels of smaller bandwidths. Additionally, this design has the flexibility to tune each channel independently to anywhere in the input bandwidth to cover a wide range of output bandwidths (from 32 MHz down to 1 kHz). Both the flexibility in channel frequency selection and the more than four orders of magnitude range in output bandwidths (decimation rates from 32 to 640,000) presented significant challenges to be solved. The solution involved breaking the digital downconversion process into a two-stage process. The first stage is a 2 oversampled filter bank that divides the whole input bandwidth as a real input signal into seven overlapping, contiguous channels represented with complex samples. Using the symmetry of the sine and cosine functions in a similar way to that of an FFT (fast Fourier transform), this downconversion is very efficient and gives seven channels fixed in frequency. An arbitrary number of smaller bandwidth channels can be formed from second-stage downconverters placed after the first stage of downconversion. Because of the overlapping of the first stage, there is no gap in coverage of the entire input bandwidth. The input to any of the second-stage downconverting channels has a multiplexer that chooses one of the seven wideband channels from the first stage. These second-stage downconverters take up fewer resources because they operate at lower bandwidths than doing the entire downconversion process from the input bandwidth for each independent channel. These second-stage downconverters are each independent with fine frequency control tuning, providing extreme flexibility in positioning the center frequency of a downconverted channel. Finally, these second-stage downconverters have flexible decimation factors over four orders of magnitude The algorithm was developed to run in an FPGA (field programmable gate array) at input data

  19. Integrated source and channel encoded digital communications system design study

    NASA Technical Reports Server (NTRS)

    Huth, G. K.

    1974-01-01

    Studies on the digital communication system for the direct communication links from ground to space shuttle and the links involving the Tracking and Data Relay Satellite (TDRS). Three main tasks were performed:(1) Channel encoding/decoding parameter optimization for forward and reverse TDRS links,(2)integration of command encoding/decoding and channel encoding/decoding; and (3) modulation coding interface study. The general communication environment is presented to provide the necessary background for the tasks and to provide an understanding of the implications of the results of the studies.

  20. The safety of copper sulfate to channel catfish eggs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper sulfate (CuSO4) is an economical treatment to control fungus (Saprolegnia spp.) on channel catfish eggs and is widely used by the industry. The purpose of this study was to determine the safety of copper sulfate to channel catfish eggs when treated at the therapeutic rate (10 mg/L), and also...

  1. Cyber Savvy: Embracing Digital Safety and Civility

    ERIC Educational Resources Information Center

    Willard, Nancy

    2012-01-01

    Concerns about children's online safety have evolved from protecting them to focusing on encouraging positive social norms, transmitting effective skills, and encouraging students to be helpful allies. In fact, federal law now requires schools that receive funding to educate students about cyber safety. Nancy Willard integrates her expertise in…

  2. The GANDALF 128-Channel Time-to-Digital Converter

    NASA Astrophysics Data System (ADS)

    Büchele, M.; Fischer, H.; Herrmann, F.; Königsmann, K.; Schill, C.; Schopferer, S.

    The GANDALF 6U-VME64x/VXS module has been designed to cope with a variety of readout tasks in high energy and nuclear physics experiments, in particular the COMPASS experiment at CERN. The exchangeable mezzanine cards allow for an employment of the system in very different applications such as analog-to-digital or time-to-digital conversions, coincidence matrix formation, fast pattern recognition or fast trigger generation. Based on this platform, we present a 128-channel TDC which is implemented in a single Xilinx Virtex-5 FPGA using a shifted clock sampling method. In this concept each input signal is continuously sampled by 16 flip-flops using equidistant phase-shifted clocks. Compared to previous FPGA designs, usually based on delay lines and comprising few TDC channels with resolutions in the order of 10 ps, our design permits the implementation of a large number of TDC channels with a resolution of 64 ps in a single FPGA. Predictable placement of logic components and uniform routing inside the FPGA fabric is a particular challenge of this design. We present measurement results for the time resolution and the nonlinearity of the TDC readout system.

  3. Evaluation of the safety of epinephrine in digital nerve blockade

    PubMed Central

    Chapeskie, Henry; Juliao, Alexis; Payne, Sonja; Koichopolos, Jennifer

    2016-01-01

    Abstract Objective To evaluate the safety profile of lidocaine containing 1:200 000 to 1:100 000 epinephrine with concurrent tourniquet use in patients undergoing toe surgery. Design A retrospective case series analysis of toe procedures performed under digital blockade with adjuvant vasopressor from January 25, 2009, to May 31, 2014, was conducted. Exclusion criteria were limited to procedures performed without adjuvant vasopressor use. Setting A single clinic in Ontario. Participants A total of 1334 toe procedures performed in 937 patients. Main outcome measures The primary study outcome was the incidence of postoperative digital necrosis. Secondary outcomes included other postoperative complications including infection, reperfusion injury, persistent granulation, and damage to the nail matrix. Results In total, 1334 toe procedures were included in this study, of which 45 involved patients with a pre-existing diagnosis of diabetes mellitus. The overall incidence of postoperative complications was low (4.6%). No cases of digital ischemia or gangrenous necrosis were observed. Subgroup analysis of patients with and without diabetes showed no statistically significant difference in the rate of complications. Conclusion This study demonstrates the safety of adjuvant vasopressor use in digital nerve blockade of the toes within a large, diverse population. This study adds to a growing base of evidence on the safety of lidocaine with 1:200 000 to 1:100 000 epinephrine for digital anesthesia.

  4. N channel JFET based digital logic gate structure

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J. (Inventor)

    2010-01-01

    A circuit topography is presented which is used to create usable digital logic gates using N (negatively doped) channel Junction Field Effect Transistors (JFETs) and load resistors, level shifting resistors, and supply rails whose values are based on the direct current (DC) parametric distributions of those JFETs. This method has direct application to the current state of the art in high temperature, for example 300.degree. C. to 500.degree. C. and higher, silicon carbide (SiC) device production. The ability to produce inverting and combinatorial logic enables the production of pulse and edge triggered latches. This scale of logic synthesis would bring digital logic and state machine capabilities to devices operating in extremely hot environments, such as the surface of Venus, near hydrothermal vents, within nuclear reactors (SiC is inherently radiation hardened), and within internal combustion engines. The basic logic gate can be configured as a driver for oscillator circuits allowing for time bases and simple digitizers for resistive or reactive sensors. The basic structure of this innovation, the inverter, can be reconfigured into various analog circuit topographies through the use of feedback structures.

  5. Safety of copper sulfate to channel catfish eggs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper sulfate (CuSO4) is commonly used in the catfish industry to control saprolegniasis (caused by watermolds) on eggs. This study was designed to establish the safety of CuSO4 when applied to hatching troughs containing channel catfish eggs in 26 degrees C flow-through well water at 10, 30, and ...

  6. Ultrasonic Digital Communication System for a Steel Wall Multipath Channel: Methods and Results

    SciTech Connect

    TL Murphy

    2006-02-16

    As of the development of this thesis, no commercially available products have been identified for the digital communication of instrumented data across a thick ({approx} 6 n.) steel wall using ultrasound. The specific goal of the current research is to investigate the application of methods for digital communication of instrumented data (i.e., temperature, voltage, etc.) across the wall of a steel pressure vessel. The acoustic transmission of data using ultrasonic transducers prevents the need to breach the wall of such a pressure vessel which could ultimately affect its safety or lifespan, or void the homogeneity of an experiment under test. Actual digital communication paradigms are introduced and implemented for the successful dissemination of data across such a wall utilizing solely an acoustic ultrasonic link. The first, dubbed the ''single-hop'' configuration, can communicate bursts of digital data one-way across the wall using the Differential Binary Phase-Shift Keying (DBPSK) modulation technique as fast as 500 bps. The second, dubbed the ''double-hop'' configuration, transmits a carrier into the vessel, modulates it, and retransmits it externally. Using a pulsed carrier with Pulse Amplitude Modulation (PAM), this technique can communicate digital data as fast as 500 bps. Using a CW carrier, Least Mean-Squared (LMS) adaptive interference suppression, and DBPSK, this method can communicate data as fast as 5 kbps. A third technique, dubbed the ''reflected-power'' configuration, communicates digital data by modulating a pulsed carrier by varying the acoustic impedance at the internal transducer-wall interface. The paradigms of the latter two configurations are believed to be unique. All modulation methods are based on the premise that the wall cannot be breached in any way and can therefore be viably implemented with power delivered wirelessly through the acoustic channel using ultrasound. Methods, results, and considerations for future research are discussed

  7. System design for a million channel digital spectrum analyzer /MCSA/. [of bandpass filtering in SETI receivers

    NASA Technical Reports Server (NTRS)

    Peterson, A.; Narasimha, M.; Narayan, S.

    1980-01-01

    The system design of a wideband (8 MHz) million-channel digital spectrum analyzer for use with a SETI receiver is presented. The analyzer makes use of a digital bandpass filter bank for transforming the wideband input signal into a specified number (120) of uniform narrowband output channels by the use of a Fourier transform digital processor combined with a prototype digital weighting network (finite impulse response filter). The output is then processed separately by 120 microprocessor-based discrete Fourier transform computers, each producing 8190 output channels of approximately 8 Hz bandwidth by the use of an 8190-point prime factor algorithm.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  9. Maximum noise-immunity of a digital communications channel with binary coding

    NASA Astrophysics Data System (ADS)

    Senderskii, V. A.; Strokov, V. V.

    1987-07-01

    The maximum noise-immunity of a digital comunications channel with binary coding is analyzed as a function of the coding rate. The investigation is carried out for two limiting cases: binary-continuous and binary symmetric channels. It is concluded that the results obtained can be used to estimate the degree to which the noise-immunity values of actual digital channels approximate the maximally possible values.

  10. Coherent optical frequency-combs-based wideband signal channelization and analog to digital conversion

    NASA Astrophysics Data System (ADS)

    Yin, Feifei; Dai, Yitang; Li, Jianqiang; Xu, Kun

    2014-11-01

    We demonstrate a photonic-assisted broadband radio frequency (RF) channelization scheme based on dual coherent optical frequency combs (OFCs). The advantages include coarse optical alignment requirement, ideal rectangular frequency response in each channel without any ultra-narrow optical filters, and digitalized output for further processing. Meanwhile, the channel frequency response and crosstalk of the scheme are also evaluated experimentally.

  11. A 1 GHz sample rate, 256-channel, 1-bit quantization, CMOS, digital correlator chip

    NASA Technical Reports Server (NTRS)

    Timoc, C.; Tran, T.; Wongso, J.

    1992-01-01

    This paper describes the development of a digital correlator chip with the following features: 1 Giga-sample/second; 256 channels; 1-bit quantization; 32-bit counters providing up to 4 seconds integration time at 1 GHz; and very low power dissipation per channel. The improvements in the performance-to-cost ratio of the digital correlator chip are achieved with a combination of systolic architecture, novel pipelined differential logic circuits, and standard 1.0 micron CMOS process.

  12. 78 FR 29392 - Embedded Digital Devices in Safety-Related Systems, Systems Important to Safety, and Items Relied...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-20

    ...The U.S. Nuclear Regulatory Commission (NRC) is issuing for public comment Draft Regulatory Issue Summary (RIS) 2013-XX, ``Embedded Digital Devices in Safety-Related Systems, Systems Important to Safety, and Items Relied on For Safety.'' The NRC staff has developed the draft RIS to clarify the NRC's technical position on existing regulatory requirements for the quality and reliability of basic......

  13. Device for modular input high-speed multi-channel digitizing of electrical data

    DOEpatents

    VanDeusen, A.L.; Crist, C.E.

    1995-09-26

    A multi-channel high-speed digitizer module converts a plurality of analog signals to digital signals (digitizing) and stores the signals in a memory device. The analog input channels are digitized simultaneously at high speed with a relatively large number of on-board memory data points per channel. The module provides an automated calibration based upon a single voltage reference source. Low signal noise at such a high density and sample rate is accomplished by ensuring the A/D converters are clocked at the same point in the noise cycle each time so that synchronous noise sampling occurs. This sampling process, in conjunction with an automated calibration, yields signal noise levels well below the noise level present on the analog reference voltages. 1 fig.

  14. Device for modular input high-speed multi-channel digitizing of electrical data

    DOEpatents

    VanDeusen, Alan L.; Crist, Charles E.

    1995-09-26

    A multi-channel high-speed digitizer module converts a plurality of analog signals to digital signals (digitizing) and stores the signals in a memory device. The analog input channels are digitized simultaneously at high speed with a relatively large number of on-board memory data points per channel. The module provides an automated calibration based upon a single voltage reference source. Low signal noise at such a high density and sample rate is accomplished by ensuring the A/D converters are clocked at the same point in the noise cycle each time so that synchronous noise sampling occurs. This sampling process, in conjunction with an automated calibration, yields signal noise levels well below the noise level present on the analog reference voltages.

  15. Network device interface for digitally interfacing data channels to a controller via a network

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2009-01-01

    A communications system and method are provided for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is converted into digital signals and transmitted to the controller. Network device interfaces associated with different data channels can coordinate communications with the other interfaces based on either a transition in a command message sent by the bus controller or a synchronous clock signal.

  16. Network device interface for digitally interfacing data channels to a controller via a network

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2007-01-01

    The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is converted into digital signals and transmitted to the controller. In some embodiments, network device interfaces associated with different data channels coordinate communications with the other interfaces based on either a transition in a command message sent by the bus controller or a synchronous clock signal.

  17. Network device interface for digitally interfacing data channels to a controller via a network

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2006-01-01

    The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface is a state machine, such as an ASIC, that operates independent of a processor in communicating with the bus controller and data channels.

  18. 78 FR 47014 - Configuration Management Plans for Digital Computer Software Used in Safety Systems of Nuclear...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ... 22, 2012 (77 FR 50727) for a 60-day public comment period. The public comment period closed on... COMMISSION Configuration Management Plans for Digital Computer Software Used in Safety Systems of Nuclear... 1 of RG 1.169, ``Configuration Management Plans for Digital Computer Software Used in Safety...

  19. Plant Modernization with Digital Reactor Protection System Safety System Upgrades at US Nuclear Power Stations

    SciTech Connect

    Heckle, Wm. Lloyd; Bolian, Tricia W.

    2006-07-01

    As the current fleet of nuclear power plants in the US reaches 25+ years of operation, obsolescence is driving many utilities to implement upgrades to both their safety and non-safety-related Instrumentation and Control (I and C) Systems. Digital technology is the predominant replacement technology for these upgrades. Within the last 15 years, digital control systems have been deployed in non-safety- related control applications at many utilities. In addition, a few utilities have replaced small safety-related systems utilizing digital technology. These systems have shown digital technology to be robust, reliable and simpler to maintain. Based upon this success, acceptance of digital technology has gained momentum with both utilities and regulatory agencies. Today, in an effort to extend the operating lives of their nuclear stations and resolve obsolescence of critical components, utilities are now pursuing digital technology for replacement of their primary safety systems. AREVA is leading this effort in the United States with the first significant digital upgrade of a major safety system. AREVA has previously completed upgrades to safety-related control systems emergency diesel engine controls and governor control systems for a hydro station which serves as the emergency power source for a nuclear station. Currently, AREVA is implementing the replacement of both the Reactor Protection System (RPS) and the Engineered Safety Features Actuation System (ESFAS) on all three units at a US PWR site. (authors)

  20. Network device interface for digitally interfacing data channels to a controller via a network

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2006-01-01

    The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted into digital signals and transmitted back to the controller. In one embodiment, the bus controller sends commands and data a defined bit rate, and the network device interface senses this bit rate and sends data back to the bus controller using the defined bit rate.

  1. Network device interface for digitally interfacing data channels to a controller via a network

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2005-01-01

    The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication.

  2. Network device interface for digitally interfacing data channels to a controller via a network

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2004-01-01

    The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication.

  3. Integrated source and channel encoded digital communication system design study

    NASA Technical Reports Server (NTRS)

    Huth, G. K.; Trumpis, B. D.; Udalov, S.

    1975-01-01

    Various aspects of space shuttle communication systems were studied. The following major areas were investigated: burst error correction for shuttle command channels; performance optimization and design considerations for Costas receivers with and without bandpass limiting; experimental techniques for measuring low level spectral components of microwave signals; and potential modulation and coding techniques for the Ku-band return link. Results are presented.

  4. A slow-speed multiple-channel analog-to-digital data logging system

    NASA Technical Reports Server (NTRS)

    Lloyd, T. C.; Flaherty, B. J.

    1973-01-01

    The system was developed to record from one up to a maximum of sixteen channels of analog data onto magnetic tape. Each analog channel of data can be sampled at rates of 1, 2, 6, 12, or 60 times per minute. The system is divided into three subunits: a digital clock, an incremental magnetic tape recorder, and a sequential converter. The interfacing requirements of these subunits are presented.

  5. Wideband Spectroscopy: The Design and Implementation of a 3 GHz, 2048 Channel Digital Spectrometer

    NASA Technical Reports Server (NTRS)

    Monroe, Ryan M.

    2011-01-01

    A state-of-the-art digital Fourier Transform spectrometer has been developed, with a combination of high bandwidth and fine resolution unavailable elsewhere. Analog signals consisting of radiation emitted by constituents in planetary atmospheres or galactic sources are downconverted and subsequently digitized by a pair of interleaved Analog-to-Digital Converters (ADC). This 6 Gsps (giga sample per second) digital representation of the analog signal is then processed through an FPGA-based streaming Fast Fourier Transform (FFT), the key development described below. Digital spectrometers have many advantages over previously used analog spectrometers, especially in terms of accuracy and resolution, both of which are particularly important for the type of scientific questions to be addressed with next-generation radiometers. The implementation, results and underlying math for this spectrometer, as well as potential for future extension to even higher bandwidth, resolution and channel orthogonality, needed to support proposed future advanced atmospheric science and radioastronomy, are discussed.

  6. Wideband Spectroscopy: The Design and Implementation of a 3 GHz Bandwidth, 8192 Channel, Polyphase Digital Spectrometer

    NASA Technical Reports Server (NTRS)

    Monroe, Ryan M.

    2011-01-01

    A family of state-of-the-art digital Fourier transform spectrometers has been developed, with a combination of high bandwidth and fine resolution unavailable elsewhere. Analog signals consisting of radiation emitted by constituents in planetary atmospheres or galactic sources are downconverted and subsequently digitized by a pair of interleaved Analog-to-Digital Converters, (ADC). This 6 Gsps (giga-sample per second) digital representation of the analog signal is then processed through an FPGA-based streaming Fast Fourier Transform (FFT), the key development described below. Digital spectrometers have many advantages over previously used analog spectrometers, especially in terms of accuracy and resolution, both of which are particularly important for the type of scientific questions to be addressed with next-generation radiometers. the implementation, results and underlying math for this spectrometer, as well as, potential for future extension to even higher bandwidth, resolution and channel orthogonality, needed to support proposed future advanced atmospheric science and radioastronomy, are discussed.

  7. Bank Transfer Over Quantum Channel With Digital Checks

    SciTech Connect

    Kanamori, Yoshito; Yoo, Seong-Moo; Sheldon, Frederick T

    2006-01-01

    In recent years, many quantum cryptographic schemes have been proposed. However, it seems that there are many technical difficulties to realize them (except Quantum Key Distributions) as practical applications. In this paper, we propose a bank transfer (i.e., funds or Electronic Funds Transfer) system utilizing both classical and quantum cryptography to provide theoretically unbreakable security. This system can be realized using current technologies (e.g., linear polarizers and Faraday rotators) and requires no additional authentication and no key distribution scheme. However, a trusted third party must keep all member banks' private keys for encryption, authentication and also for functions to generate classical digital signatures.

  8. Digital Channels in Teacher-Parent Communication: The Case of Estonia

    ERIC Educational Resources Information Center

    Palts, Karmen; Kalmus, Veronika

    2015-01-01

    The aim of this paper is to analyse the attitudes of Estonian primary school teachers and parents regarding the role of mutual digital communication in socialising the child and in the child's academic progress, their communication channel preferences, and related experiences and opinions. The main starting points are Bronfenbrenner's (1979)…

  9. Dual-channel in-line digital holographic double random phase encryption

    PubMed Central

    Das, Bhargab; Yelleswarapu, Chandra S; Rao, D V G L N

    2012-01-01

    We present a robust encryption method for the encoding of 2D/3D objects using digital holography and virtual optics. Using our recently developed dual-plane in-line digital holography technique, two in-line digital holograms are recorded at two different planes and are encrypted using two different double random phase encryption configurations, independently. The process of using two mutually exclusive encryption channels makes the system more robust against attacks since both the channels should be decrypted accurately in order to get a recognizable reconstruction. Results show that the reconstructed object is unrecognizable even when the portion of the correct phase keys used during decryption is close to 75%. The system is verified against blind decryptions by evaluating the SNR and MSE. Validation of the proposed method and sensitivities of the associated parameters are quantitatively analyzed and illustrated. PMID:23471012

  10. Linux-PC based 1024-Channel Transient Digitizer System for the DRIFT Experiment Acquisition System

    NASA Astrophysics Data System (ADS)

    Ayad, R.; Hanson-Hart, Z.; Hyatt, M.; Katz-Hyman, M.; Maher, P.; Martoff, C. J.; Posner, A.; Freytag, D.; Freytag, M.; Haller, G.; Nelson, D.

    2003-04-01

    The DRIFT Experiment [1] is an underground search for WIMP Dark Matter using a novel detector invented for this purpose: the Negative Ion TPC (NITPC). The data acquisition system for DRIFT had to allow acquisition of long duration time digitized data from the 1024 analog channels at an affordable price. This was accomplished with a system based on a Linux PC, the Comedi [2] open-source device driver software, the inexpensive PCI-DIO-32HS National Instruments high speed digital I/O board, and custom 32-channel preamp+digitizer boards built at SLAC. System architecture, testing, and performance will be discussed, as well as further upgrade plans. [1] Low Pressure Negative Ion TPC for Dark Matter Search. D. P. Snowden-Ifft, C. J. Martoff, J. M. Burwell, Phys Rev. D. Rapid Comm. 61, 101301 (2000) [2] Comedi: linux Control and MEasurement Device Interface : http://stm.lbl.gov/comedi/

  11. Network device interface for digitally interfacing data channels to a controller a via network

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2006-01-01

    The present invention provides a network device interface and method for digitally connecting a plurality of data channels to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. In one embodiment, the bus controller transmits messages to the network device interface containing a plurality of bits having a value defined by a transition between first and second states in the bits. The network device interface determines timing of the data sequence of the message and uses the determined timing to communicate with the bus controller.

  12. 78 FR 47015 - Software Requirement Specifications for Digital Computer Software Used in Safety Systems of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ... issued with a temporary identification as Draft Regulatory Guide, DG-1209 on August 22, 2012 (77 FR 50726... COMMISSION Software Requirement Specifications for Digital Computer Software Used in Safety Systems of... 1 of RG 1.172, ``Software Requirement Specifications for Digital Computer Software used in...

  13. 78 FR 47804 - Verification, Validation, Reviews, and Audits for Digital Computer Software Used in Safety...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-06

    ... identification as Draft Regulatory Guide, DG-1267 on August 22, 2012 (77 FR 50723) for a 60-day public comment... COMMISSION Verification, Validation, Reviews, and Audits for Digital Computer Software Used in Safety Systems...), revision 2 of RG 1.168, ``Verification, Validation, Reviews, and Audits for Digital Computer Software...

  14. A tone-aided dual vestigial sideband system for digital communications on fading channels

    NASA Technical Reports Server (NTRS)

    Hladik, Stephen M.; Saulnier, Gary J.; Rafferty, William

    1989-01-01

    A spectrally efficient tone-aided dual vestigial sideband (TA/DVSB) system for digital data communications on fading channels is presented and described analytically. This PSK (phase-shift-keying) system incorporates a feed-forward, tone-aided demodulation technique to compensate for Doppler frequency shift and channel- induced, multipath fading. In contrast to other tone-in-band-type systems, receiver synchronization is derived from the complete data VSBs. Simulation results for the Rician fading channel are presented. These results demonstrate the receiver's ability to mitigate performance degradation due to fading and to obtain proper data carrier synchronization, suggesting that the proposed TA/DVSB system has promise for this application. Simulated BER (bit-error rate) data indicate that the TA/DVSB system effectively alleviates the channel distortions of the land mobile satellite application.

  15. The use of copper sulfate in channel catfish hatcheries: Safety and effectiveness

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper sulfate (CuSO4) is an economical treatment to control fungus (Saprolegnia spp.) on channel catfish eggs and is widely used by the industry. Several studies were designed to determine the effectiveness and safety of CuSO4 to channel catfish eggs in pursuit of an FDA-approval. Effectiveness:...

  16. 33 CFR 165.808 - Corpus Christi Ship Channel, Corpus Christi, TX, safety zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CFR 165.23 apply. (c) The Captain of the Port will notify the maritime community of periods during... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Corpus Christi Ship Channel... § 165.808 Corpus Christi Ship Channel, Corpus Christi, TX, safety zone. (a) The following areas...

  17. 33 CFR 165.808 - Corpus Christi Ship Channel, Corpus Christi, TX, safety zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CFR 165.23 apply. (c) The Captain of the Port will notify the maritime community of periods during... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Corpus Christi Ship Channel... § 165.808 Corpus Christi Ship Channel, Corpus Christi, TX, safety zone. (a) The following areas...

  18. Statistical mechanical analysis of the linear vector channel in digital communication

    NASA Astrophysics Data System (ADS)

    Takeda, Koujin; Hatabu, Atsushi; Kabashima, Yoshiyuki

    2007-11-01

    A statistical mechanical framework to analyze linear vector channel models in digital wireless communication is proposed for a large system. The framework is a generalization of that proposed for code-division multiple-access systems in Takeda et al (2006 Europhys. Lett. 76 1193) and enables the analysis of the system in which the elements of the channel transfer matrix are statistically correlated with each other. The significance of the proposed scheme is demonstrated by assessing the performance of an existing model of multi-input multi-output communication systems.

  19. Reaching a few picosecond timing precision with the 16-channel digitizer and timestamper SAMPIC ASIC

    NASA Astrophysics Data System (ADS)

    Delagnes, E.; Breton, D.; Grabas, H.; Maalmi, J.; Rusquart, P.

    2015-07-01

    SAMPIC is a Time and Waveform to Digital Converter (TWDC) multichannel chip. It integrates 16 channels each including DLL-based TDC providing a raw time associated with an ultra-fast analog memory sampling the signal used for precise timing measurements as well as other parameters of the pulse. Every channel also integrates a discriminator that can trigger it independently or participate to a more complex trigger. After triggering, the analog samples are digitized by on-chip ADCs and are sent serially to the acquisition. The paper describes the architecture of SAMPIC and reports the main performance measured on the first prototype chip with a focus on timing resolution in the range of 15 ps RMS using raw data improved to less than 5 ps RMS after a simple calibration.

  20. A high speed direct digital frequency synthesizer based on multi-channel structure

    NASA Astrophysics Data System (ADS)

    Ling, Yuan; Qiang, Zhang; Yin, Shi

    2015-06-01

    This paper presents a direct digital frequency synthesizer (DDFS) for high speed application based on multi-channel structure. This DDFS has phase resolution of 32 bits and magnitude resolution of 12 bits. In order to ensure the high speed and high resolution at the same time, the multi-channel sampling technique is used and a 12 bits linear digital-to-analog converter is implemented. The chip is fabricated in TSMC 130 nm CMOS technology with active area of 0.89 × 0.98 mm2 and total power consumption of 300 mW at a single 1.2 V supply voltage. The maximum operating speed is up to 2.0 GHz at room temperature.

  1. Spectrally shaped DP-16QAM super-channel transmission with multi-channel digital back-propagation.

    PubMed

    Maher, Robert; Xu, Tianhua; Galdino, Lidia; Sato, Masaki; Alvarado, Alex; Shi, Kai; Savory, Seb J; Thomsen, Benn C; Killey, Robert I; Bayvel, Polina

    2015-01-01

    The achievable transmission capacity of conventional optical fibre communication systems is limited by nonlinear distortions due to the Kerr effect and the difficulty in modulating the optical field to effectively use the available fibre bandwidth. In order to achieve a high information spectral density (ISD), while simultaneously maintaining transmission reach, multi-channel fibre nonlinearity compensation and spectrally efficient data encoding must be utilised. In this work, we use a single coherent super-receiver to simultaneously receive a DP-16QAM super-channel, consisting of seven spectrally shaped 10GBd sub-carriers spaced at the Nyquist frequency. Effective nonlinearity mitigation is achieved using multi-channel digital back-propagation (MC-DBP) and this technique is combined with an optimised forward error correction implementation to demonstrate a record gain in transmission reach of 85%; increasing the maximum transmission distance from 3190 km to 5890 km, with an ISD of 6.60 b/s/Hz. In addition, this report outlines for the first time, the sensitivity of MC-DBP gain to linear transmission line impairments and defines a trade-off between performance and complexity. PMID:25645457

  2. Spectrally Shaped DP-16QAM Super-Channel Transmission with Multi-Channel Digital Back-Propagation

    PubMed Central

    Maher, Robert; Xu, Tianhua; Galdino, Lidia; Sato, Masaki; Alvarado, Alex; Shi, Kai; Savory, Seb J.; Thomsen, Benn C.; Killey, Robert I.; Bayvel, Polina

    2015-01-01

    The achievable transmission capacity of conventional optical fibre communication systems is limited by nonlinear distortions due to the Kerr effect and the difficulty in modulating the optical field to effectively use the available fibre bandwidth. In order to achieve a high information spectral density (ISD), while simultaneously maintaining transmission reach, multi-channel fibre nonlinearity compensation and spectrally efficient data encoding must be utilised. In this work, we use a single coherent super-receiver to simultaneously receive a DP-16QAM super-channel, consisting of seven spectrally shaped 10GBd sub-carriers spaced at the Nyquist frequency. Effective nonlinearity mitigation is achieved using multi-channel digital back-propagation (MC-DBP) and this technique is combined with an optimised forward error correction implementation to demonstrate a record gain in transmission reach of 85%; increasing the maximum transmission distance from 3190 km to 5890 km, with an ISD of 6.60 b/s/Hz. In addition, this report outlines for the first time, the sensitivity of MC-DBP gain to linear transmission line impairments and defines a trade-off between performance and complexity. PMID:25645457

  3. Wideband aperture array using RF channelizers and massively parallel digital 2D IIR filterbank

    NASA Astrophysics Data System (ADS)

    Sengupta, Arindam; Madanayake, Arjuna; Gómez-García, Roberto; Engeberg, Erik D.

    2014-05-01

    Wideband receive-mode beamforming applications in wireless location, electronically-scanned antennas for radar, RF sensing, microwave imaging and wireless communications require digital aperture arrays that offer a relatively constant far-field beam over several octaves of bandwidth. Several beamforming schemes including the well-known true time-delay and the phased array beamformers have been realized using either finite impulse response (FIR) or fast Fourier transform (FFT) digital filter-sum based techniques. These beamforming algorithms offer the desired selectivity at the cost of a high computational complexity and frequency-dependant far-field array patterns. A novel approach to receiver beamforming is the use of massively parallel 2-D infinite impulse response (IIR) fan filterbanks for the synthesis of relatively frequency independent RF beams at an order of magnitude lower multiplier complexity compared to FFT or FIR filter based conventional algorithms. The 2-D IIR filterbanks demand fast digital processing that can support several octaves of RF bandwidth, fast analog-to-digital converters (ADCs) for RF-to-bits type direct conversion of wideband antenna element signals. Fast digital implementation platforms that can realize high-precision recursive filter structures necessary for real-time beamforming, at RF radio bandwidths, are also desired. We propose a novel technique that combines a passive RF channelizer, multichannel ADC technology, and single-phase massively parallel 2-D IIR digital fan filterbanks, realized at low complexity using FPGA and/or ASIC technology. There exists native support for a larger bandwidth than the maximum clock frequency of the digital implementation technology. We also strive to achieve More-than-Moore throughput by processing a wideband RF signal having content with N-fold (B = N Fclk/2) bandwidth compared to the maximum clock frequency Fclk Hz of the digital VLSI platform under consideration. Such increase in bandwidth is

  4. On the effect of timing errors in run length codes. [redundancy removal algorithms for digital channels

    NASA Technical Reports Server (NTRS)

    Wilkins, L. C.; Wintz, P. A.

    1975-01-01

    Many redundancy removal algorithms employ some sort of run length code. Blocks of timing words are coded with synchronization words inserted between blocks. The probability of incorrectly reconstructing a sample because of a channel error in the timing data is a monotonically nondecreasing function of time since the last synchronization word. In this paper we compute the 'probability that the accumulated magnitude of timing errors equal zero' as a function of time since the last synchronization word for a zero-order predictor (ZOP). The result is valid for any data source that can be modeled by a first-order Markov chain and any digital channel that can be modeled by a channel transition matrix. An example is presented.

  5. Equalization and detection for digital communication over nonlinear bandlimited satellite communication channels. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Gutierrez, Alberto, Jr.

    1995-01-01

    This dissertation evaluates receiver-based methods for mitigating the effects due to nonlinear bandlimited signal distortion present in high data rate satellite channels. The effects of the nonlinear bandlimited distortion is illustrated for digitally modulated signals. A lucid development of the low-pass Volterra discrete time model for a nonlinear communication channel is presented. In addition, finite-state machine models are explicitly developed for a nonlinear bandlimited satellite channel. A nonlinear fixed equalizer based on Volterra series has previously been studied for compensation of noiseless signal distortion due to a nonlinear satellite channel. This dissertation studies adaptive Volterra equalizers on a downlink-limited nonlinear bandlimited satellite channel. We employ as figure of merits performance in the mean-square error and probability of error senses. In addition, a receiver consisting of a fractionally-spaced equalizer (FSE) followed by a Volterra equalizer (FSE-Volterra) is found to give improvement beyond that gained by the Volterra equalizer. Significant probability of error performance improvement is found for multilevel modulation schemes. Also, it is found that probability of error improvement is more significant for modulation schemes, constant amplitude and multilevel, which require higher signal to noise ratios (i.e., higher modulation orders) for reliable operation. The maximum likelihood sequence detection (MLSD) receiver for a nonlinear satellite channel, a bank of matched filters followed by a Viterbi detector, serves as a probability of error lower bound for the Volterra and FSE-Volterra equalizers. However, this receiver has not been evaluated for a specific satellite channel. In this work, an MLSD receiver is evaluated for a specific downlink-limited satellite channel. Because of the bank of matched filters, the MLSD receiver may be high in complexity. Consequently, the probability of error performance of a more practical

  6. The 128-channel fully differential digital integrated neural recording and stimulation interface.

    PubMed

    Shahrokhi, Farzaneh; Abdelhalim, Karim; Serletis, Demitre; Carlen, Peter L; Genov, Roman

    2010-06-01

    We present a fully differential 128-channel integrated neural interface. It consists of an array of 8 X 16 low-power low-noise signal-recording and generation circuits for electrical neural activity monitoring and stimulation, respectively. The recording channel has two stages of signal amplification and conditioning with and a fully differential 8-b column-parallel successive approximation (SAR) analog-to-digital converter (ADC). The total measured power consumption of each recording channel, including the SAR ADC, is 15.5 ¿W. The measured input-referred noise is 6.08 ¿ Vrms over a 5-kHz bandwidth, resulting in a noise efficiency factor of 5.6. The stimulation channel performs monophasic or biphasic voltage-mode stimulation, with a maximum stimulation current of 5 mA and a quiescent power dissipation of 51.5 ¿W. The design is implemented in 0.35-¿m complementary metal-oxide semiconductor technology with the channel pitch of 200 ¿m for a total die size of 3.4 mm × 2.5 mm and a total power consumption of 9.33 mW. The neural interface was validated in in vitro recording of a low-Mg(2+)/high-K(+) epileptic seizure model in an intact hippocampus of a mouse. PMID:23853339

  7. Predicting Bed Grain Size in Threshold Channels Using Lidar Digital Elevation Models

    NASA Astrophysics Data System (ADS)

    Snyder, N. P.; Nesheim, A. O.; Wilkins, B. C.; Edmonds, D. A.

    2011-12-01

    Over the past 20 years, researchers have developed GIS-based algorithms to extract channel networks and measure longitudinal profiles from digital elevation models (DEMs), and have used these to study stream morphology in relation to tectonics, climate and ecology. The accuracy of stream elevations from traditional DEMs (10-50 m pixels) is typically limited by the contour interval (3-20 m) of the rasterized topographic map source. This is a particularly severe limitation in low-relief watersheds, where 3 m of channel elevation change may occur over several km. Lidar DEMs (~1 m pixels) allow researchers to resolve channel elevation changes of ~0.5 m, enabling reach-scale calculations of gradient, which is the most important parameter for understanding channel processes at that scale. Lidar DEMs have the additional advantage of allowing users to make estimates of channel width. We present a process-based model that predicts median bed grain size in threshold gravel-bed channels from lidar slope and width measurements using the Shields and Manning equations. We compare these predictions to field grain size measurements in segments of three Maine rivers. Like many paraglacial rivers, these have longitudinal profiles characterized by relatively steep (gradient >0.002) and flat (gradient <0.0005) segments, with length scales of several km. This heterogeneity corresponds to strong variations in channel form, sediment supply, bed grain size, and aquatic habitat characteristics. The model correctly predicts bed sediment size within a factor of two in ~70% of the study sites. The model works best in single-thread channels with relatively low sediment supply, and poorly in depositional, multi-thread and/or fine (median grain size <20 mm) reaches. We evaluate the river morphology (using field and lidar measurements) in the context of the Parker et al. (2007) hydraulic geometry relations for single-thread gravel-bed rivers, and find correspondence in the locations where both

  8. Multiprocessor architecture to handle TJ-II VXI-based digitization channels

    NASA Astrophysics Data System (ADS)

    Crémy, C.; Vega, J.; Sánchez, E.; Dulya, C. M.; Portas, A.

    1999-01-01

    The data acquisition System (DAS) of the TJ-II stellerator provides up to 300 digitization channels integrated in register-based VXI modules designed in CIEMAT Laboratories. The modules are embedded into six 13-slot VXI chassis connected to the TJ-II DAS central computer by means of a dual LAN topology. During normal operation, remote control of the VXI systems and channel setup are accomplished through an Ethernet LAN, while two FDDI rings are dedicated to postdischarge fast data transfer. The former network link is performed by the bus controller whereas the latter one is provided through a FDDI node controller installed in the mainframe, thus creating a multiprocessor architecture. Dedicated software, running on the VxWorks operating system, has been developed to provide handling of the VXI systems including the following facilities: mainframe information readout, channel setup, real time digitization handling, and data transfer. This software, implemented in C++, is distributed over the two CPUs. Interprocessor communication for synchronization purposes is based on a backplane shared memory pool.

  9. Digitalized K(+) Occupancy in the Nanocavity Holds and Releases Queues of K(+) in a Channel.

    PubMed

    Sumikama, Takashi; Oiki, Shigetoshi

    2016-08-17

    The mechanisms of ion permeation through potassium channels have been extensively examined. Molecular dynamics (MD) simulations have demonstrated that rapidly permeating ions collide near the selectivity filter (SF) ("knock-on" mechanism), but this oversimplified mechanism is insufficient to account for the experimentally observed single-channel current amplitudes. Here, we analyzed the MD-simulated ion trajectories through a Kv1.2 potassium channel using an event-oriented analysis method, and surprisingly, we found that the nanocavity (NC) governs ion permeation in a digital fashion. The NC has a maximal diameter of 10 Å and stands between the intracellular bulk solution and the SF, which holds only up to one K(+) during permeation. Accordingly, the K(+) concentration in the intracellular solution is translated as a digitalized zero or one K(+) in the NC. When the ion number in the NC is zero, the multiple ions in the SF are mostly immobilized. By contrast, when the number of ions in the NC is one, the structured water in the NC mediates the ion-occupied status to the queueing ions in the SF, and the ions then initiate a collective outward motion. Accordingly, the one ion in the NC serves as a catalytic intermediate for permeation, which quantitatively accounts for the experimentally obtained conductance-concentration relationships. We conclude that the ion movements are coherent across the entire pore. PMID:27454924

  10. A new safety channel based on ¹⁷N detection in research reactors.

    PubMed

    Seyfi, Somayye; Gharib, Morteza

    2015-10-01

    Tehran research reactor (TRR) is a representative of pool type research reactors using light water, as coolant and moderator. This reactor is chosen as a prototype to demonstrate and prove the feasibility of (17)N detection as a new redundant channel for reactor power measurement. In TRR, similar to other pool type reactors, neutron detectors are immersed in the pool around the core as the main power measuring devices. In the present article, a different approach, using out of water neutron detector, is employed to measure reactor power. This new method is based on (17)O (n,p) (17)N reaction taking place inside the core and subsequent measurement of delayed neutrons emitted due to (17)N disintegration. Count and measurement of neutrons around outlet water pipe provides a reliable redundant safety channel to measure reactor power. Results compared with other established channels indicate a good agreement and shows a linear interdependency with true thermal power. Safety of reactor operation is improved with installation & use of this new power measuring channel. The new approach may equally serve well as a redundant channel in all other types of reactors having coolant comprised of oxygen in its molecular constituents. Contrary to existing channels, this one is totally out of water and thus is an advantage over current instrumentations. It is proposed to employ the same idea on other reactors (nuclear power plants too) to improve safety criteria. PMID:26123105

  11. Eight channel - 16 bit, bidirectional analog to digital monitoring and control system

    SciTech Connect

    Allen, J.C.; Callis, R.W.; Cary, W.P.; Harris, T.E.; Nerem, A.

    1991-11-01

    The DIII-D tokamak facility is currently upgrading its electron cyclotron resonance heating (ECH) system. The new system is based on 110 GHz gyrotrons developed by Varian. As part of this upgrade, the superconducting magnet power supplies were required to be remotely controlled and monitored accurately. The 110 GHz gyrotron superconducting magnet has eight coils, that are energized by current regulating power supplies. An analog to digital (A/D) system was designed to allow remote coil current monitoring and power supply programming. The A/D system is an eight channel multiplexed, 16 bit, bidirectional, fiber optically linked, analog to digital telemetry system. Design concerns and trade-offs will be discussed as will the results of in system use.

  12. Safety Evaluation of Stamp Type Digital Microneedle Devices in Hairless Mice

    PubMed Central

    Park, Kui Young; Jang, Woo Sun; Lim, Yun Young; Ahn, Joo Hee; Lee, Sang Jin; Kim, Chan Woong; Kim, Sung Eun; Kim, Myeung Nam

    2013-01-01

    Background Microneedles provide a minimally invasive means to transport molecules into the skin. A number of specific strategies have been employed to use microneedles for transdermal delivery. Objective The purpose of this study was to investigate the safety of two new digital microneedle devices (Digital Hand® and Digital Pro®; Bomtech Electronics Co., Ltd., Seoul, Korea) for the perforation of skin in skin-hairless-1 mice. This device replaces conventional needles and is designed specifically for intradermal delivery. Methods We used two newly developed digital microneedle devices to perforate the skin of skin-hairless-1 mice. We conducted a comparative study of the two digital microneedle devices and DTS® (Disk type-microneedle Therapy System; DTS lab., Seoul, Korea). To evaluate skin stability, we performed visual and dermatoscopic inspections, measurements of transepidermal water loss, and biopsies. Results The two novel digital microneedle devices did not induce significant abnormalities of the skin on visual or dermatoscopic inspection, regardless of needle size (0.25~2.0 mm). No significant histopathological changes, such as inflammatory cell infiltration, desquamation of the stratum corneum, or disruption of the basal layer, were observed. The digital microneedle devices and microneedle therapy system produced similar results on measures of skin stability. Conclusion These two novel digital microneedle devices are safe transdermal drug delivery systems. PMID:23467706

  13. Digital Real-Time Multiple Channel Multiple Mode Neutron Flux Estimation on FPGA-based Device

    NASA Astrophysics Data System (ADS)

    Thevenin, Mathieu; Barbot, Loïc; Corre, Gwénolé; Woo, Romuald; Destouches, Christophe; Normand, Stéphane

    2016-02-01

    This paper presents a complete custom full-digital instrumentation device that was designed for real-time neutron flux estimation, especially for nuclear reactor in-core measurement using subminiature Fission Chambers (FCs). Entire fully functional small-footprint design (about 1714 LUTs) is implemented on FPGA. It enables real-time acquisition and analysis of multiple channels neutron's flux both in counting mode and Campbelling mode. Experimental results obtained from this brand new device are consistent with simulation results and show good agreement within good uncertainty. This device paves the way for new applications perspectives in real-time nuclear reactor monitoring.

  14. JPL 2-to-the-20th-power channel 300 MHz bandwidth digital spectrum analyzer

    NASA Technical Reports Server (NTRS)

    Morris, G. A., Jr.; Wilck, H. C.

    1978-01-01

    A million (two to the 20th power) channel, 300 MHz bandwidth, digital spectrum analyzer was considered. The design, fabrication, and maintenance philosophy of the modular, pipelined, fast fourier transform (FFT) hardware are described. The spectrum analyzer will be used to examine the region from 1.4 GHz to 26 GHz for radio frequency interference which may be harmful to present and future tracking missions of the Deep Space Network. The design has application to the search for extraterrestrial intelligence signals and radio science phenomena.

  15. 78 FR 47011 - Software Unit Testing for Digital Computer Software Used in Safety Systems of Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ... identification as Draft Regulatory Guide, DG-1208 on August 22, 2012 (77 FR 50722) for a 60-day public comment... COMMISSION Software Unit Testing for Digital Computer Software Used in Safety Systems of Nuclear Power Plants..., ``Software Unit Testing for Digital Computer Software Used in Safety Systems of Nuclear Power Plants.''...

  16. 78 FR 47805 - Test Documentation for Digital Computer Software Used in Safety Systems of Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-06

    ... issued with a temporary identification as Draft Regulatory Guide, DG-1207 on August 22, 2012 (77 FR 50720... COMMISSION Test Documentation for Digital Computer Software Used in Safety Systems of Nuclear Power Plants..., ``Test Documentation for Digital Computer Software Used in Safety Systems of Nuclear Power Plants.''...

  17. 77 FR 50723 - Verification, Validation, Reviews, and Audits for Digital Computer Software Used in Safety...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...The U.S. Nuclear Regulatory Commission (NRC or the Commission) is issuing for public comment draft regulatory guide (DG), DG-1267, ``Verification, Validation, Reviews, and Audits for Digital Computer Software used in Safety Systems of Nuclear Power Plants.'' The DG-1210 is proposed Revision 2 of Regulatory Guide (RG) 1.168, dated February 2004. This revision endorses, with clarifications and......

  18. 77 FR 50727 - Configuration Management Plans for Digital Computer Software Used in Safety Systems of Nuclear...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...The U.S. Nuclear Regulatory Commission (NRC or the Commission) is issuing for public comment draft regulatory guide (DG), DG-1206, ``Configuration Management Plan for Digital Computer Software Used in Safety Systems of Nuclear Power Plants.'' The DG-1206 is proposed Revision 1 of RG 1.169, dated September 1997. This revision endorses, with clarifications, the enhanced consensus practices for......

  19. Digital database of channel cross-section surveys, Mount St. Helens, Washington

    USGS Publications Warehouse

    Mosbrucker, Adam R.; Spicer, Kurt R.; Major, Jon J.; Saunders, Dennis R.; Christianson, Tami S.; Kingsbury, Cole G.

    2015-01-01

    Stream-channel cross-section survey data are a fundamental component to studies of fluvial geomorphology. Such data provide important parameters required by many open-channel flow models, sediment-transport equations, sediment-budget computations, and flood-hazard assessments. At Mount St. Helens, Washington, the long-term response of channels to the May 18, 1980, eruption, which dramatically altered the hydrogeomorphic regime of several drainages, is documented by an exceptional time series of repeat stream-channel cross-section surveys. More than 300 cross sections, most established shortly following the eruption, represent more than 100 kilometers of surveyed topography. Although selected cross sections have been published previously in print form, we present a comprehensive digital database that includes geospatial and tabular data. Furthermore, survey data are referenced to a common geographic projection and to common datums. Database design, maintenance, and data dissemination are accomplished through a geographic information system (GIS) platform, which integrates survey data acquired with theodolite, total station, and global navigation satellite system (GNSS) instrumentation. Users can interactively perform advanced queries and geospatial time-series analysis. An accuracy assessment provides users the ability to quantify uncertainty within these data. At the time of publication, this project is ongoing. Regular database updates are expected; users are advised to confirm they are using the latest version.

  20. 78 FR 669 - Safety Zone; Hampton Harbor Channel Obstruction, Hampton Harbor; Hampton, NH

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-04

    ... prohibit vessels from coming within 100 yards of point 42 53'763'' N, 070 48'986'' W until the obstruction...) 366-9826. SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal... obstruction to the channel. This safety zone will encompass all waters within a 100 yard radius of...

  1. 75 FR 38019 - Safety Zone; Fixed Mooring Balls, South of Barbers Pt. Harbor Channel, Oahu, HI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Fixed Mooring Balls, South of Barbers Pt. Harbor Channel, Oahu, HI AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: Due to...

  2. Redundant safety features in a high-channel-count retinal neurostimulator

    PubMed Central

    Kelly, Shawn K.; Ellersick, William F.; Krishnan, Ashwati; Doyle, Patrick; Shire, Douglas B.; Wyatt, John L.; Rizzo, Joseph F.

    2016-01-01

    Safety features embedded in a 256-channel retinal prosthesis integrated circuit are presented. The biology of the retina and the electrochemistry of the electrode-tissue interface demand careful planning and design of the safety features of an implantable retinal stimulation device. We describe the internal limits and communication safety features of our ASIC, but we focus on monitoring and protection circuits for the electrode-tissue interface. Two independent voltage monitoring circuits for each channel measure the electrode polarization voltage at two different times in the biphasic stimulation cycle. The monitors ensure that the charged electrode stays within the electrochemical water window potentials, and that the discharged electrode is within a small window near the counter electrode potential. A switch to connect each electrode to the counter electrode between pulses protects against a wide range of device failures. Additionally, we describe work on an active feedback system to ensure that the electrode voltage is at zero.

  3. Method and apparatus for a single channel digital communications system. [synchronization of received PCM signal by digital correlation with reference signal

    NASA Technical Reports Server (NTRS)

    Couvillon, L. A., Jr.; Carl, C.; Goldstein, R. M.; Posner, E. C.; Green, R. R. (Inventor)

    1973-01-01

    A method and apparatus are described for synchronizing a received PCM communications signal without requiring a separate synchronizing channel. The technique provides digital correlation of the received signal with a reference signal, first with its unmodulated subcarrier and then with a bit sync code modulated subcarrier, where the code sequence length is equal in duration to each data bit.

  4. The use of linear programming techniques to design optimal digital filters for pulse shaping and channel equalization

    NASA Technical Reports Server (NTRS)

    Houts, R. C.; Burlage, D. W.

    1972-01-01

    A time domain technique is developed to design finite-duration impulse response digital filters using linear programming. Two related applications of this technique in data transmission systems are considered. The first is the design of pulse shaping digital filters to generate or detect signaling waveforms transmitted over bandlimited channels that are assumed to have ideal low pass or bandpass characteristics. The second is the design of digital filters to be used as preset equalizers in cascade with channels that have known impulse response characteristics. Example designs are presented which illustrate that excellent waveforms can be generated with frequency-sampling filters and the ease with which digital transversal filters can be designed for preset equalization.

  5. Evaluation of Ocean Color Scanner (OCS) photographic and digital data: Santa Barbara Channel test site, 29 October 1975 overflight

    NASA Technical Reports Server (NTRS)

    Kraus, S. P.; Estes, J. E.; Kronenberg, M. R.; Hajic, E. J.

    1977-01-01

    A summary of Ocean Color Scanner data was examined to evaluate detection and discrimination capabilities of the system for marine resources, oil pollution and man-made sea surface targets of opportunity in the Santa Barbara Channel. Assessment of the utility of OCS for the determination of sediment transport patterns along the coastal zone was a secondary goal. Data products provided 1975 overflight were in digital and analog formats. In evaluating the OCS data, automated and manual procedures were employed. A total of four channels of data in digital format were analyzed, as well as three channels of color combined imagery, and four channels of black and white imagery. In addition, 1:120,000 scale color infrared imagery acquired simultaneously with the OCS data were provided for comparative analysis purposes.

  6. Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

    NASA Astrophysics Data System (ADS)

    Bechstein, S.; Petsche, F.; Scheiner, M.; Drung, D.; Thiel, F.; Schnabel, A.; Schurig, Th

    2006-06-01

    Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/√Hz was specially designed for a 304-channel low-Tc dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm × 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm × 4 cm × 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented.

  7. On nonlinearly-induced noise in single-channel optical links with digital backpropagation.

    PubMed

    Beygi, Lotfollah; Irukulapati, Naga V; Agrell, Erik; Johannisson, Pontus; Karlsson, Magnus; Wymeersch, Henk; Serena, Paolo; Bononi, Alberto

    2013-11-01

    In this paper, we investigate the performance limits of electronic chromatic dispersion compensation (EDC) and digital backpropagation (DBP) for a single-channel non-dispersion-managed fiber-optical link. A known analytical method to derive the performance of the system with EDC is extended to derive a first-order approximation for the performance of the system with DBP. In contrast to the cubic growth of the variance of the nonlinear noise-like interference, often called nonlinear noise, with input power for EDC, a quadratic growth is observed with DBP using this approximation. Finally, we provide numerical results to verify the accuracy of the proposed approach and compare it with existing analytical models. PMID:24216860

  8. Digital single-channel seismic-reflection data from western Santa Monica basin

    USGS Publications Warehouse

    Normark, William R.; Piper, David J.W.; Sliter, Ray W.; Triezenberg, Peter; Gutmacher, Christina E.

    2006-01-01

    During a collaborative project in 1992, Geological Survey of Canada and United States Geological Survey scientists obtained about 850 line-km of high-quality single-channel boomer and sleeve-gun seismic-reflection profiles across Hueneme, Mugu and Dume submarine fans, Santa Monica Basin, off southern California. The goals of this work were to better understand the processes that lead to the formation of sandy submarine fans and the role of sea-level changes in controlling fan development. This report includes a trackline map of the area surveyed, as well as images of the sleeve-gun profiles and the opportunity to download both images and digital data files (SEG-Y) of all the sleeve-gun profiles.

  9. Interconnected but underprotected? Parents' methods and motivations for information seeking on digital safety issues.

    PubMed

    Davis, Vauna

    2012-12-01

    Parents need information and skills to meet the demands of mediating connected technology in their homes. Parents' methods and motivations for learning to protect children from digital risks were reported through a survey. This study explores relationships between information seeking, parents' concerns, risks children have experienced, and access to connected devices, in addition to the use and satisfaction of various digital safety resources. Three types of information-seeking behavior were identified: (a) protective information seeking, to protect children from being confronted with harmful content; (b) problem-solving information seeking, to help children who have been negatively affected by connected technology; and (c) attentive learning, by attending to media resources passively encountered on this topic. Friends and family are the dominant source of digital safety information, followed by presentations and the Internet. Parents' top concerns for their children using connected technology were accidental exposure to pornography, and sexual content in Internet-based entertainment. Higher numbers of risks experienced by children were positively associated with parents' problem-solving information seeking and level of attentive learning. Parents who were more concerned exhibited more problem-solving information seeking; but despite the high level of concern for children's safety online, 65 percent of parents seek information on this subject less than twice per year. Children have access to a mean of five connected devices at home; a higher number of devices was correlated with increased risks experienced by children, but was not associated with increased concern or information seeking from parents. PMID:23098226

  10. A 256 channel 8-Bit current digitizer ASIC for the Belle-II PXD

    NASA Astrophysics Data System (ADS)

    Knopf, J.; Fischer, P.; Kreidl, C.; Peric, I.

    2011-01-01

    The international DEPFET collaboration is developing a silicon pixel vertex detector (PXD), based on monolithic arrays of DEPFET transistors, for the future physics experiment Belle-II at the SuperKEKB particle accelerator in Japan. The matrix elements are read out in a 'rolling shutter mode', i.e. rows are selected consecutively and all columns are read out in each cycle of < 100 ns. One of the major parts in the front-end electronics chain is the DEPFET Current Digitizer ASIC (DCDB). It is now in a close-to-final state. The chip provides 256 channels of analog-to-digital converters with a resolution of six to eight bits. Each converter features an individual dynamic offset correction circuit as well as programmable gain and bandwidth. Several operation modes using single sampling or double correlated sampling are possible. A large synthesized digital block is used for decoding and derandomization of the conversion results. The data is put out on eight 8-bit links, operating at a speed of 400 MHz. Additionally, a JTAG compatible interface is implemented for configuration and debugging purpose. Significant effort was made to reduce the power consumption of the DCDB, since both, voltage drop on the internal power buses and heat sources in the Belle-II experiment are a concern. The chip was realized on a 3.2mm × 5mm die using the UMC 180nm CMOS technology in a multi-project wafer run, provided by EuroPractice. An extra redistribution metal layer with bump bond pads is used, allowing for flipping the chip onto the final all-silicon DEPFET sensor module. Several tests have been performed in order to prove the chip's operation and its quality in terms of noise. The results are presented.

  11. High speed multi-channel optical sampling technique for analog-to-digital converters

    NASA Astrophysics Data System (ADS)

    Noman, Mohammad; Donkor, Eric; Hayduk, Michael J.; Bussjager, Rebecca J.

    2005-05-01

    We describe the design and implementation of an eight channel optical sampling technique for analog-to-digital (A/D) converters. A single mode-locked laser source with a pulse reprtition rate of 250 MHz is used to generate eight highly synchronized smapling clocks each running at 500 MHz. The basic sampling circuit consistes of a reversed-biased photodiode which operates as a very fast optoelectronic switch. Actuating the photodiode ON and OFF with mode-locked laser pulses produce sampled RF signals. In the implementation of this A/D architecture, the optical clocks are delayed relative to each other using fixed passive delay lines. The time-shifted clock signals allow for sampling different phases of the input RF signal resulting in an aggregate sampling rate of 4 Gigasamples/sec (GSPS). We shall show the optical clock setup necessary in order to achieve a 4 BSPS rate. We shall also present sampling results for input RF signals with frequencies ranging from 10 to 500. Interleaving of the sampled RF output from different sampling channels will also be demonstrated.

  12. High Resolution Photogrammetric Digital Elevation Models Across Calving Fronts and Meltwater Channels in Greenland

    NASA Astrophysics Data System (ADS)

    Le Bel, D. A.; Brown, S.; Zappa, C. J.; Bell, R. E.; Frearson, N.; Tinto, K. J.

    2014-12-01

    Photogrammetric digital elevation models (DEMs) are a powerful approach for understanding elevation change and dynamics along the margins of the large ice sheets. The IcePod system, mounted on a New York Air National Guard LC-130, can measure high-resolution surface elevations with a Riegl VQ580 scanning laser altimeter and Imperx Bobcat IGV-B6620 color visible-wavelength camera (6600x4400 resolution); the surface temperature with a Sofradir IRE-640L infrared camera (spectral response 7.7-9.5 μm, 640x512 resolution); and the structure of snow and ice with two radar systems. We show the use of IcePod imagery to develop DEMs across calving fronts and meltwater channels in Greenland. Multiple over-flights of the Kangerlussaq Airport ramp have provided a test of the technique at a location with accurate, independently-determined elevation. Here the photogrammetric DEM of the airport, constrained by ground control measurements, is compared with the Lidar results. In July 2014 the IcePod ice-ocean imaging system surveyed the calving fronts of five outlet glaciers north of Jakobshavn Isbrae. We used Agisoft PhotoScan to develop a DEM of each calving front using imagery captured by the IcePod systems. Adjacent to the ice sheet, meltwater plumes foster mixing in the fjord, moving warm ocean water into contact with the front of the ice sheet where it can undercut the ice front and trigger calving. The five glaciers provide an opportunity to examine the calving front structure in relation to ocean temperature, fjord circulation, and spatial scale of the meltwater plumes. The combination of the accurate DEM of the calving front and the thermal imagery used to constrain the temperature and dynamics of the adjacent plume provides new insights into the ice-ocean interactions. Ice sheet margins provide insights into the connections between the surface meltwater and the fate of the water at the ice sheet base. Surface meltwater channels are visualized here for the first time using

  13. A 128-channel Time-to-Digital Converter (TDC) inside a Virtex-5 FPGA on the GANDALF module

    NASA Astrophysics Data System (ADS)

    Büchele, M.; Fischer, H.; Gorzellik, M.; Herrmann, F.; Königsmann, K.; Schill, C.; Schopferer, S.

    2012-03-01

    The GANDALF 6U-VME64x/VXS module has been developed for the digitization and real time analysis of detector signals. To perform different applications such as analog-to-digital or time-to-digital conversions, coincidence matrix formation, fast pattern recognition and trigger generation, this module comes with exchangeable analog and digital mezzanine cards. Based on this platform, we present a 128-channel TDC which is implemented in a single Xilinx Virtex-5 FPGA using a shifted clock sampling method. In contrast to common TDC concepts, the input signal is sampled by 16 equidistant phase-shifted clocks. A particular challenge of the design is the minimum skew routing of the input signals to the sampling flip-flops. We present measurement results for the differential nonlinearity and the time resolution of the TDC readout system.

  14. A 96-channel FPGA-based time-to-digital converter

    SciTech Connect

    Bogdan, Mircea; Frisch, Henry; Heintz, Mary; Paramonov, Alexander; Sanders, Harold; Chappa, Steve; DeMaat, Robert; Klein, Rod; Miao, Ting; Phillips, Thomas J; Wilson, Peter

    2005-02-01

    We describe an FPGA-based, 96-channel, time-to-digital converter (TDC) intended for use with the Central Outer Tracker (COT) [1] in the CDF Experiment [2] at the Fermilab Tevatron. The COT system is digitized and read out by 315 TDC cards, each serving 96 wires of the chamber. The TDC is physically configured as a 9U VME card. The functionality is almost entirely programmed in firmware in two Altera Stratix FPGA’s. The special capabilities of this device are the availability of 840 MHz LVDS inputs, multiple phase-locked clock modules, and abundant memory. The TDC system operates with an input resolution of 1.2 ns, a minimum input pulse width of 4.8 ns and a minimum separation of 4.8 ns between pulses. Each input can accept up to 7 hits per collision. The time-to-digital conversion is done by first sampling each of the 96 inputs in 1.2-ns bins and filling a circular memory; the memory addresses of logical transitions (edges) in the input data are then translated into the time of arrival and width of the COT pulses. Memory pipelines with a depth of 5.5 μs allow deadtime-less operation in the first-level trigger; the data are multiple-buffered to diminish deadtime in the second-level trigger. The complete process of edge-detection and filling of buffers for readout takes 12 μs. The TDC VME interface allows a 64-bit Chain Block Transfer of multiple boards in a crate with transfer-rates up to 47 Mbytes/sec. The TDC also contains a separately-programmed data path that produces prompt trigger data every Tevatron crossing. The trigger bits are clocked onto the P3 VME backplane connector with a 22-ns clock for transmission to the trigger. The full TDC design and multi-card test results are described. The physical simplicity ensures low-maintenance; the functionality being in firmware allows reprogramming for other applications.

  15. Digital safety I and C system in the Paks NPP (Hungary))

    SciTech Connect

    Eiler, J.

    2006-07-01

    The entire replacement of the original, Russian safety I and C system in the Paks NPP concluded successfully in 2003. The new, digital system was selected after a very thorough tendering process and installation was performed within the time-frame of normal refueling outages. The new system has shown very high reliability and flexibility in the past years. Several other nuclear power plants have initiated / completed the same replacement using the same type of equipment. This paper provides a summary on selected technical and organizational issues, as well as the main lessons learned in this very comprehensive and wide-scale project. (authors)

  16. Joint-source-channel coding scheme for scalable video-coding-based digital video broadcasting, second generation satellite broadcasting system

    NASA Astrophysics Data System (ADS)

    Seo, Kwang-Deok; Chi, Won Sup; Lee, In Ki; Chang, Dae-Ig

    2010-10-01

    We propose a joint-source-channel coding (JSCC) scheme that can provide and sustain high-quality video service in spite of deteriorated transmission channel conditions of the second generation of the digital video broadcasting (DVB-S2) satellite broadcasting service. Especially by combining the layered characteristics of the SVC (scalable video coding) video and the robust channel coding capability of LDPC (low-density parity check) employed for DVB-S2, a new concept of JSCC for digital satellite broadcasting service is developed. Rain attenuation in high-frequency bands such as the Ka band is a major factor for lowering the link capacity in satellite broadcasting service. Therefore, it is necessary to devise a new technology to dynamically manage the rain attenuation by adopting a JSCC scheme that can apply variable code rates for both source and channel coding. For this purpose, we develop a JSCC scheme by combining SVC and LDPC, and prove the performance of the proposed JSCC scheme by extensive simulations where SVC coded video is transmitted over various error-prone channels with AWGN (additive white Gaussian noise) patterns in DVB-S2 broadcasting service.

  17. Biophysics and Molecular Biology of Cardiac Ion Channels for the Safety Pharmacologist.

    PubMed

    Pugsley, Michael K; Curtis, Michael J; Hayes, Eric S

    2015-01-01

    Cardiac safety pharmacology is a continuously evolving discipline that uses the basic principles of pharmacology in a regulatory-driven process to generate data to inform risk/benefit assessment of a new chemical entity (NCE). The aim of cardiac safety pharmacology is to characterise the pharmacodynamic/pharmacokinetic (PK/PD) relationship of a drug's adverse effects on the heart using continuously evolving methodology. Unlike Toxicology, safety pharmacology includes within its remit a regulatory requirement to predict the risk of rare cardiotoxic (potentially lethal) events such as torsades de pointes (TdP), which is statistically associated with drug-induced changes in the QT interval of the ECG due to blockade of I Kr or K v11.1 current encoded by hERG. This gives safety pharmacology its unique character. The key issues for the safety pharmacology assessment of a drug on the heart are detection of an adverse effect liability, projection of the data into safety margin calculation and clinical safety monitoring. This chapter will briefly review the current cardiac safety pharmacology paradigm outlined in the ICH S7A and ICH S7B guidance documents and the non-clinical models and methods used in the evaluation of new chemical entities in order to define the integrated risk assessment for submission to regulatory authorities. An overview of how the present cardiac paradigm was developed will be discussed, explaining how it was based upon marketing authorisation withdrawal of many non-cardiovascular compounds due to unanticipated proarrhythmic effects. The role of related biomarkers (of cardiac repolarisation, e.g. prolongation of the QT interval of the ECG) will be considered. We will also provide an overview of the 'non-hERG-centric' concepts utilised in the evolving comprehensive in vitro proarrhythmia assay (CIPA) that details conduct of the proposed ion channel battery test, use of human stem cells and application of in silico models to early cardiac safety

  18. Advanced Concepts for Pressure-Channel Reactors: Modularity, Performance and Safety

    NASA Astrophysics Data System (ADS)

    Duffey, Romney B.; Pioro, Igor L.; Kuran, Sermet

    Based on an analysis of the development of advanced concepts for pressure-tube reactor technology, we adapt and adopt the pressure-tube reactor advantage of modularity, so that the subdivided core has the potential for optimization of the core, safety, fuel cycle and thermal performance independently, while retaining passive safety features. In addition, by adopting supercritical water-cooling, the logical developments from existing supercritical turbine technology and “steam” systems can be utilized. Supercritical and ultra-supercritical boilers and turbines have been operating for some time in coal-fired power plants. Using coolant outlet temperatures of about 625°C achieves operating plant thermal efficiencies in the order of 45-48%, using a direct turbine cycle. In addition, by using reheat channels, the plant has the potential to produce low-cost process heat, in amounts that are customer and market dependent. The use of reheat systems further increases the overall thermal efficiency to 55% and beyond. With the flexibility of a range of plant sizes suitable for both small (400 MWe) and large (1400 MWe) electric grids, and the ability for co-generation of electric power, process heat, and hydrogen, the concept is competitive. The choice of core power, reheat channel number and exit temperature are all set by customer and materials requirements. The pressure channel is a key technology that is needed to make use of supercritical water (SCW) in CANDU®1 reactors feasible. By optimizing the fuel bundle and fuel channel, convection and conduction assure heat removal using passive-moderator cooling. Potential for severe core damage can be almost eliminated, even without the necessity of activating the emergency-cooling systems. The small size of containment structure lends itself to a small footprint, impacts economics and building techniques. Design features related to Canadian concepts are discussed in this paper. The main conclusion is that development of

  19. Equalization enhanced phase noise in Nyquist-spaced superchannel transmission systems using multi-channel digital back-propagation

    NASA Astrophysics Data System (ADS)

    Xu, Tianhua; Liga, Gabriele; Lavery, Domaniç; Thomsen, Benn C.; Savory, Seb J.; Killey, Robert I.; Bayvel, Polina

    2015-09-01

    Superchannel transmission spaced at the symbol rate, known as Nyquist spacing, has been demonstrated for effectively maximizing the optical communication channel capacity and spectral efficiency. However, the achievable capacity and reach of transmission systems using advanced modulation formats are affected by fibre nonlinearities and equalization enhanced phase noise (EEPN). Fibre nonlinearities can be effectively compensated using digital back-propagation (DBP). However EEPN which arises from the interaction between laser phase noise and dispersion cannot be efficiently mitigated, and can significantly degrade the performance of transmission systems. Here we report the first investigation of the origin and the impact of EEPN in Nyquist-spaced superchannel system, employing electronic dispersion compensation (EDC) and multi-channel DBP (MC-DBP). Analysis was carried out in a Nyquist-spaced 9-channel 32-Gbaud DP-64QAM transmission system. Results confirm that EEPN significantly degrades the performance of all sub-channels of the superchannel system and that the distortions are more severe for the outer sub-channels, both using EDC and MC-DBP. It is also found that the origin of EEPN depends on the relative position between the carrier phase recovery module and the EDC (or MC-DBP) module. Considering EEPN, diverse coding techniques and modulation formats have to be applied for optimizing different sub-channels in superchannel systems.

  20. Equalization enhanced phase noise in Nyquist-spaced superchannel transmission systems using multi-channel digital back-propagation

    PubMed Central

    Xu, Tianhua; Liga, Gabriele; Lavery, Domaniç; Thomsen, Benn C.; Savory, Seb J.; Killey, Robert I.; Bayvel, Polina

    2015-01-01

    Superchannel transmission spaced at the symbol rate, known as Nyquist spacing, has been demonstrated for effectively maximizing the optical communication channel capacity and spectral efficiency. However, the achievable capacity and reach of transmission systems using advanced modulation formats are affected by fibre nonlinearities and equalization enhanced phase noise (EEPN). Fibre nonlinearities can be effectively compensated using digital back-propagation (DBP). However EEPN which arises from the interaction between laser phase noise and dispersion cannot be efficiently mitigated, and can significantly degrade the performance of transmission systems. Here we report the first investigation of the origin and the impact of EEPN in Nyquist-spaced superchannel system, employing electronic dispersion compensation (EDC) and multi-channel DBP (MC-DBP). Analysis was carried out in a Nyquist-spaced 9-channel 32-Gbaud DP-64QAM transmission system. Results confirm that EEPN significantly degrades the performance of all sub-channels of the superchannel system and that the distortions are more severe for the outer sub-channels, both using EDC and MC-DBP. It is also found that the origin of EEPN depends on the relative position between the carrier phase recovery module and the EDC (or MC-DBP) module. Considering EEPN, diverse coding techniques and modulation formats have to be applied for optimizing different sub-channels in superchannel systems. PMID:26365422

  1. Cryocooled wideband digital channelizing radio-frequency receiver based on low-pass ADC

    NASA Astrophysics Data System (ADS)

    Vernik, Igor V.; Kirichenko, Dmitri E.; Dotsenko, Vladimir V.; Miller, Robert; Webber, Robert J.; Shevchenko, Pavel; Talalaevskii, Andrei; Gupta, Deepnarayan; Mukhanov, Oleg A.

    2007-11-01

    We have demonstrated a digital receiver performing direct digitization of radio-frequency signals over a wide frequency range from kilohertz to gigahertz. The complete system, consisting of a cryopackaged superconductor all-digital receiver (ADR) chip followed by room-temperature interface electronics and a field programmable gate array (FPGA) based post-processing module, has been developed. The ADR chip comprises a low-pass analog-to-digital converter (ADC) delta modulator with phase modulation-demodulation architecture together with digital in-phase and quadrature mixer and a pair of digital decimation filters. The chip is fabricated using a 4.5 kA cm-2 process and is cryopackaged using a commercial-off-the-shelf cryocooler. Experimental results in HF, VHF, UHF and L bands and their analysis, proving consistent operation of the cryopackaged ADR chip up to 24.32 GHz clock frequency, are presented and discussed.

  2. Sensitivity Analysis of Digital I&C Modules in Protection and Safety Systems

    NASA Astrophysics Data System (ADS)

    Khalil Ur, Rahman; Zubair, M.; Heo, G.

    2013-12-01

    This research is performed to examine the sensitivity of digital Instrumentation and Control (I&C) components and modules used in regulating and protection systems architectures of nuclear industry. Fault Tree Analysis (FTA) was performed for four configurations of RPS channel architecture. The channel unavailability has been calculated by using AIMS-PSA, which comes out 4.517E-03, 2.551E-03, 2.246E-03 and 2.7613-04 for architecture configuration I, II, III and IV respectively. It is observed that unavailability decreases by 43.5 % & 50.4% by inserting partial redundancy whereas maximum reduction of 93.9 % in unavailability happens when double redundancy is inserted in architecture. Coincidence module output failure and bi-stable output failures are identified as sensitive failures by Risk Reduction Worth (RRW) and Fussell-Vesely (FV) importance. RRW highlights that risk from coincidence processor output failure can reduced by 48.83 folds and FV indicates that BP output is sensitive by 0.9796 (on a scale of 1).

  3. A novel computed method to reconstruct the bilateral digital interarticular channel of atlas and its use on the anterior upper cervical screw fixation

    PubMed Central

    Wu, Ai-Min; Wang, Wenhai; Xu, Hui; Lin, Zhong-Ke; Yang, Xin-Dong; Wang, Xiang-Yang; Xu, Hua-Zi

    2016-01-01

    Purpose. To investigate a novel computed method to reconstruct the bilateral digital interarticular channel of atlas and its potential use on the anterior upper cervical screw fixation. Methods. We have used the reverse engineering software (image-processing software and computer-aided design software) to create the approximate and optimal digital interarticular channel of atlas for 60 participants. Angles of channels, diameters of inscribed circles, long and short axes of ellipses were measured and recorded, and gender-specific analysis was also performed. Results. The channels provided sufficient space for one or two screws, and the parameters of channels are described. While the channels of females were smaller than that of males, no significant difference of angles between males and females were observed. Conclusion. Our study demonstrates the radiological features of approximate digital interarticular channels, optimal digital interarticular channels of atlas, and provides the reference trajectory of anterior transarticular screws and anterior occiput-to-axis screws. Additionally, we provide a protocol that can help make a pre-operative plan for accurate placement of anterior transarticular screws and anterior occiput-to-axis screws. PMID:26925345

  4. Applications of Multi-Channel Safety Authentication Protocols in Wireless Networks.

    PubMed

    Chen, Young-Long; Liau, Ren-Hau; Chang, Liang-Yu

    2016-01-01

    People can use their web browser or mobile devices to access web services and applications which are built into these servers. Users have to input their identity and password to login the server. The identity and password may be appropriated by hackers when the network environment is not safe. The multiple secure authentication protocol can improve the security of the network environment. Mobile devices can be used to pass the authentication messages through Wi-Fi or 3G networks to serve as a second communication channel. The content of the message number is not considered in a multiple secure authentication protocol. The more excessive transmission of messages would be easier to collect and decode by hackers. In this paper, we propose two schemes which allow the server to validate the user and reduce the number of messages using the XOR operation. Our schemes can improve the security of the authentication protocol. The experimental results show that our proposed authentication protocols are more secure and effective. In regard to applications of second authentication communication channels for a smart access control system, identity identification and E-wallet, our proposed authentication protocols can ensure the safety of person and property, and achieve more effective security management mechanisms. PMID:26547846

  5. Multi-channel nonlinearity compensation of PDM-QPSK signals in dispersion-managed transmission using dispersion-folded digital backward propagation.

    PubMed

    Xia, Cen; Liu, Xiang; Chandrasekhar, S; Fontaine, N K; Zhu, Likai; Li, G

    2014-03-10

    We demonstrate nonlinearity compensation of 37.5-GHz-spaced 128-Gb/s PDM-QPSK signals using dispersion-folded digital-backward-propagation and a spectrally-sliced receiver that simultaneously receives three WDM signals, showing mitigation of intra-channel and inter-channel nonlinear effects in a 2560-km dispersion-managed TWRS-fiber link. Intra-channel and adjacent inter-channel nonlinear compensation gains when WDM channels are fully populated in the C-band are estimated based on the GN-model. PMID:24663923

  6. 77 FR 50722 - Software Unit Testing for Digital Computer Software Used in Safety Systems of Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...The U.S. Nuclear Regulatory Commission (NRC or the Commission) is issuing for public comment draft regulatory guide (DG), DG-1208, ``Software Unit Testing for Digital Computer Software used in Safety Systems of Nuclear Power Plants.'' The DG-1208 is proposed Revision 1 of RG 1.171, dated September 1997. This revision endorses, with clarifications, the enhanced consensus practices for testing......

  7. 77 FR 50724 - Developing Software Life Cycle Processes for Digital Computer Software Used in Safety Systems of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...The U.S. Nuclear Regulatory Commission (NRC or the Commission) is issuing for public comment draft regulatory guide (DG), DG-1210, ``Developing Software Life Cycle Processes for Digital Computer Software used in Safety Systems of Nuclear Power Plants.'' The DG-1210 is proposed Revision 1 of RG 1.173, dated September 1997. This revision endorses, with clarifications, the enhanced consensus......

  8. 77 FR 50720 - Test Documentation for Digital Computer Software Used in Safety Systems of Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...The U.S. Nuclear Regulatory Commission (NRC or the Commission) is issuing for public comment draft regulatory guide (DG), DG-1207, ``Test Documentation for Digital Computer Software used in Safety Systems of Nuclear Power Plants.'' The DG-1207 is proposed Revision 1 of RG 1.170, dated September 1997. This revision endorses, with clarifications, the enhanced consensus practices for test......

  9. Safety analysis of high pressure 3He-filled micro-channels for thermal neutron detection.

    SciTech Connect

    Ferko, Scott M.; Galambos, Paul C.; Derzon, Mark Steven; Renzi, Ronald F.

    2008-11-01

    This document is a safety analysis of a novel neutron detection technology developed by Sandia National Laboratories. This technology is comprised of devices with tiny channels containing high pressure {sup 3}He. These devices are further integrated into large scale neutron sensors. Modeling and preliminary device testing indicates that the time required to detect the presence of special nuclear materials may be reduced under optimal conditions by several orders of magnitude using this approach. Also, these devices make efficient use of our {sup 3}He supply by making individual devices more efficient and/or extending the our limited {sup 3}He supply. The safety of these high pressure devices has been a primary concern. We address these safety concerns for a flat panel configuration intended for thermal neutron detection. Ballistic impact tests using 3 g projectiles were performed on devices made from FR4, Silicon, and Parmax materials. In addition to impact testing, operational limits were determined by pressurizing the devices either to failure or until they unacceptably leaked. We found that (1) sympathetic or parasitic failure does not occur in pressurized FR4 devices (2) the Si devices exhibited benign brittle failure (sympathetic failure under pressure was not tested) and (3) the Parmax devices failed unacceptably. FR4 devices were filled to pressures up to 4000 + 100 psig, and the impacts were captured using a high speed camera. The brittle Si devices shattered, but were completely contained when wrapped in thin tape, while the ductile FR4 devices deformed only. Even at 4000 psi the energy density of the compressed gas appears to be insignificant compared to the impact caused by the incoming projectile. In conclusion, the current FR4 device design pressurized up to 4000 psi does not show evidence of sympathetic failure, and these devices are intrinsically safe.

  10. Estimation of channel mismatches in time-interleaved analog-to-digital converters based on fractional delay and sine curve fitting.

    PubMed

    Guo, Lianping; Tian, Shulin; Jiang, Jun

    2015-03-01

    This paper proposes an algorithm to estimate the channel mismatches in time-interleaved analog-to-digital converter (TIADC) based on fractional delay (FD) and sine curve fitting. Choose one channel as the reference channel and apply FD to the output samples of reference channel to obtain the ideal samples of non-reference channels with no mismatches. Based on least square method, the sine curves are adopted to fit the ideal and the actual samples of non-reference channels, and then the mismatch parameters can be estimated by comparing the ideal sine curves and the actual ones. The principle of this algorithm is simple and easily understood. Moreover, its implementation needs no extra circuits, lowering the hardware cost. Simulation results show that the estimation accuracy of this algorithm can be controlled within 2%. Finally, the practicability of this algorithm is verified by the measurement results of channel mismatch errors of a two-channel TIADC prototype. PMID:25832264

  11. A digital atlas of ion channel expression patterns in the two-week-old rat brain.

    PubMed

    Shcherbatyy, Volodymyr; Carson, James; Yaylaoglu, Murat; Jäckle, Katharina; Grabbe, Frauke; Brockmeyer, Maren; Yavuz, Halenur; Eichele, Gregor

    2015-01-01

    The approximately 350 ion channels encoded by the mammalian genome are a main pillar of the nervous system. We have determined the expression pattern of 320 channels in the two-week-old (P14) rat brain by means of non-radioactive robotic in situ hybridization. Optimized methods were developed and implemented to generate stringently coronal brain sections. The use of standardized methods permits a direct comparison of expression patterns across the entire ion channel expression pattern data set and facilitates recognizing ion channel co-expression. All expression data are made publically available at the Genepaint.org database. Inwardly rectifying potassium channels (Kir, encoded by the Kcnj genes) regulate a broad spectrum of physiological processes. Kcnj channel expression patterns generated in the present study were fitted with a deformable subdivision mesh atlas produced for the P14 rat brain. This co-registration, when combined with numerical quantification of expression strengths, allowed for semi-quantitative automated annotation of expression patterns as well as comparisons among and between Kcnj subfamilies. The expression patterns of Kcnj channel were also cross validated against previously published expression patterns of Kcnj channel genes. PMID:25284011

  12. The safety and effectiveness of CuSO4 to control fungus on intact egg masses in channel catfish hatcheries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper sulfate (CuSO4) is widely used by the catfish industry as an economical treatment to control fungus (Saprolegnia spp.) on channel catfish eggs. This is an overview of our effectiveness and safety studies for the proposed indication ‘to control egg mortality associated with Saprolegniasis inf...

  13. Innovative frequency measurement technique used in the design of a single channel frequency to digital converter ASIC

    NASA Astrophysics Data System (ADS)

    Ramalingam, Neranjen; Varadan, Vijay K.; Varadan, Vasundara V.

    1996-09-01

    The frequency to digital converter (FDC) is an application specific integrated circuit. The chip has been designed to handle one input channel but can easily be expanded to handle multiple channels of frequencies. The channel is capable of measuring frequencies from 100 Hz to 100 kHz. The power consumption of the chip is very low. The frequency measurement accuracy is better than 0.1 percent. The conversion rate per channel is 100 samples/second which can be carried too. The chip has a built-in test equipment to verify its operation. It is able to generate frequencies like 8 Mhz, 4Mhz, 2Mhz and 1Mhz which can be fed as optional clock frequencies depending on the accuracy desired. The FDC chip can be interfaced to a 16 bit bus. To meet these stringent specifications of the FDC chip an innovative frequency measurement technique has been devised called the hybrid technique of frequency measurement. The technique proves to be very accurate and it is found that by varying the sampling rate the range of input frequencies over which this accuracy can be achieved also changes. The specifications are particularly strict so that it is possible to use the chip for any military application for which a very reliable operation is demanded. The FDC chip is hence ideal for control and guidance purposes. The chip has wide ranging applications. In conjunction with sensors such as accelerometers it can be used to design smart sensors. The chip can play a vital role in engine controllers and in pressure measurements using vibrating type transducers. Sometimes to isolate transducers, the output is converted to frequency and isolation is achieved using opto-isolators; then by measuring the frequency using this chip this can be converted to digital information.

  14. Development of a 512-Channel Module for Digital X-Ray Imaging Systems with Silicon Strip Detectors

    SciTech Connect

    Bolanos, L.; Cabal, A. E.; Grybos, P.; Maj, P.; Swientek, K.; Szczygiel, R.; Marzari, A.; Prino, F.; Ramello, L.

    2008-08-11

    We present the development of a 512-channel module for high counting rate digital X-ray imaging systems. The module consists of 512 silicon micro-strips equipped with 8 64-channel readout ASICs called DEDIX. The detectors of 300 {mu}m thickness have strips with 100 micron pitch and strip length of 1 or 2 cm. Detectors were designed with the possibility of choosing the cutting edge distance from the active area in the range from 60 {mu}m down to 20 {mu}m. To obtain good detection efficiency at the relevant energies (10-50 keV) the module works in edge-on configuration: strips are oriented parallel to the incoming X-ray beam. The DEDIX ASIC has a binary readout architecture. Each channel is built of a charge sensitive amplifier (CSA) with pole-zero cancellation circuit, a shaper, two independent discriminators and two independent 20-bit counters. Internal correction DAC implemented in each channel independently ensures a low spread of discriminator effective threshold. This module has been characterized for noise and matching performance having in mind possible future applications like dual energy mammography and angiography. An equivalent noise charge is below 210 el rms for a 1 cm long strip detector and below 250 el. rms for 2 cm long strip detector with 100 {mu}m pitch. The spread of discriminator effective threshold for 512 channels is 16 el. rms, while the high counting rate performance has been demonstrated by the measurement up to 1 MHz average rate of input signals per single channel.

  15. Multi-DSP and FPGA based Multi-channel Direct IF/RF Digital receiver for atmospheric radar

    NASA Astrophysics Data System (ADS)

    Yasodha, Polisetti; Jayaraman, Achuthan; Kamaraj, Pandian; Durga rao, Meka; Thriveni, A.

    2016-07-01

    Modern phased array radars depend highly on digital signal processing (DSP) to extract the echo signal information and to accomplish reliability along with programmability and flexibility. The advent of ASIC technology has made various digital signal processing steps to be realized in one DSP chip, which can be programmed as per the application and can handle high data rates, to be used in the radar receiver to process the received signal. Further, recent days field programmable gate array (FPGA) chips, which can be re-programmed, also present an opportunity to utilize them to process the radar signal. A multi-channel direct IF/RF digital receiver (MCDRx) is developed at NARL, taking the advantage of high speed ADCs and high performance DSP chips/FPGAs, to be used for atmospheric radars working in HF/VHF bands. Multiple channels facilitate the radar t be operated in multi-receiver modes and also to obtain the wind vector with improved time resolution, without switching the antenna beam. MCDRx has six channels, implemented on a custom built digital board, which is realized using six numbers of ADCs for simultaneous processing of the six input signals, Xilinx vertex5 FPGA and Spartan6 FPGA, and two ADSPTS201 DSP chips, each of which performs one phase of processing. MCDRx unit interfaces with the data storage/display computer via two gigabit ethernet (GbE) links. One of the six channels is used for Doppler beam swinging (DBS) mode and the other five channels are used for multi-receiver mode operations, dedicatedly. Each channel has (i) ADC block, to digitize RF/IF signal, (ii) DDC block for digital down conversion of the digitized signal, (iii) decoding block to decode the phase coded signal, and (iv) coherent integration block for integrating the data preserving phase intact. ADC block consists of Analog devices make AD9467 16-bit ADCs, to digitize the input signal at 80 MSPS. The output of ADC is centered around (80 MHz - input frequency). The digitized data is fed

  16. A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

    NASA Technical Reports Server (NTRS)

    Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

    2011-01-01

    ultimately impact the surface of Europa after the mission is completed. The current JEO mission concept includes a range of instruments on the payload, to monitor dynamic phenomena (such as Io's volcanoes and Jupiters atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. The payload includes a low mass (3.7 Kg) and low power (< 5 W) Thermal Instrument (TI) concept for measuring possible warm thermal anomalies on Europa s cold surface caused by recent (< 10,000 years) eruptive activity. Regions of anomalously high heat flow will be identified by thermal mapping using a nadir pointing, push-broom filter radiometer that provides far-IR imagery in two broad band spectral wavelength regions, 8-20 m and 20-100 m, for surface temperature measurements with better than a 2 K accuracy and a spatial resolution of 250 m/pixel obtained from a 100 Km orbit. The temperature accuracy permits a search for elevated temperatures when combined with albedo information. The spatial resolution is sufficient to resolve Europa's larger cracks and ridge axial valleys. In order to accomplish the thermal mapping, the TI uses sensitive thermopile arrays that are readout by a custom designed low-noise Multi-Channel Digitizer (MCD) ASIC that resides very close to the thermopile linear array outputs. Both the thermopile array and the MCD ASIC will need to show full functionality within the harsh Jovian radiation environment, operating at cryogenic temperatures, typically 150 K to 170 K. In the following, a radiation mitigation strategy together with a low risk Radiation-Hardened-By-Design (RHBD) methodology using commercial foundry processes is given for the design and manufacture of a MCD ASIC that will meet this challenge.

  17. Channel calibration for digital array radar in the presence of amplitude-phase and mutual coupling errors

    NASA Astrophysics Data System (ADS)

    Li, Weixing; Zhang, Yue; Lin, Jianzhi; Chen, Zengping

    2015-10-01

    Amplitude-phase errors and mutual coupling errors among multi-channels in digital array radar (DAR) will seriously deteriorate the performance of signal processing such as digital beam-forming (DBF) and high resolution direction finding. In this paper, a combined algorithm for error calibration in DAR has been demonstrated. The algorithm firstly estimates the amplitude-phase errors of each channel using interior calibration sources with the help of the calibration network. Then the signals from far field are received and the amplitude-phase errors are compensated. According to the subspace theories, the relationship between the principle eigenvectors and distorted steering vectors is expressed, and the cost function containing the mutual coupling matrix (MCM) and incident directions is established. Making use of the properties of MCM of uniform linear array, Gauss-Newton method is implied to iteratively compute the MCM and the direction of arrival (DOA). Simulation results have shown the effectiveness and performance of proposed algorithm. Based on an 8-elements DAR test-bed, experiments are carried out in anechoic chamber. The results illustrate that the algorithm is feasible in actual systems.

  18. TARGET: A multi-channel digitizer chip for very-high-energy gamma-ray telescopes

    SciTech Connect

    Bechtol, K.; Funk, S.; Okumura, A.; Ruckman, L.; Simons, A.; Tajima, H.; Vandenbroucke, J.; Varner, G.; /Hawaii U.

    2011-08-11

    The next-generation very-high-energy (VHE) gamma-ray observatory, the Cherenkov Telescope Array, will feature dozens of imaging atmospheric Cherenkov telescopes (IACTs), each with thousands of pixels of photosensors. To be affordable and reliable, reading out such a mega-channel array requires event recording technology that is highly integrated and modular, with a low cost per channel. We present the design and performance of a chip targeted to this application: the TeV Array Readout with GSa/s sampling and Event Trigger (TARGET). This application-specific integrated circuit (ASIC) has 16 parallel input channels, a 4096-sample buffer for each channel, adjustable input termination, self-trigger functionality, and tight window-selected readout. We report the performance of TARGET in terms of sampling frequency, power consumption, dynamic range, current-mode gain, analog bandwidth, and cross talk. The large number of channels per chip allows a low cost per channel ($10 to $20 including front-end and back-end electronics but not including photosensors) to be achieved with a TARGET-based IACT readout system. In addition to basic performance parameters of the TARGET chip itself, we present a camera module prototype as well as a second-generation chip (TARGET 2), both of which have been produced.

  19. A numerical solution to define channel heads and hillslope parameters from digital topography of glacially conditioned catchments

    NASA Astrophysics Data System (ADS)

    Salcher, Bernhard; Baumann, Sebastian; Kober, Florian; Robl, Jörg; Heiniger, Lukas

    2016-04-01

    The analysis of the slope-area relationship in bedrock streams is a common way for discriminating the channel from the hillslope domain and associated landscape processes. Spatial variations of these domains are important indicators of landscape change. In fluvial catchments, this relationship is a function of contributing drainage area, channel slope and the threshold drainage area for fluvial erosion. The resulting pattern is related to climate, tectonic and underlying bedrock. These factors may become secondary in catchments affected by glacial erosion, as it is the case in many mid- to high-latitude mountain belts. The perturbation (i.e. the destruction) of an initial steady state fluvial bedrock morphology (where uplift is balanced by surface lowering rates) will tend to become successively larger if the repeated action of glacial processes exceeds the potential of fluvial readjustment during deglaciated periods. Topographic change is associated with a decrease and fragmentation of the channel network and an extension of the hillslope domain. In case of glacially conditioned catchments discrimination of the two domains remains problematic and a discrimination inconsistent. A definition is therefore highly needed considering that (i) a spatial shift in the domains affect the process and rate of erosion and (ii) topographic classifications of alpine catchments often base on channel and hillslope parameters (i.e.channel or hillslope relief). Here we propose a novel numerical approach to topographically define channel heads from digital topography in glacially conditioned mountain range catchments in order to discriminate the channel from the hillslope domain. We analyzed the topography of the southern European Central Alps, a region which (i) has been glaciated multiple times during the Quaternary, shows (ii) little lithological variations, is (iii) home of very low erodible rocks and is (iv) known as a region were tectonic processes have largely ceased. The

  20. Pharmaceutical digital marketing and governance: illicit actors and challenges to global patient safety and public health

    PubMed Central

    2013-01-01

    Background Digital forms of direct-to-consumer pharmaceutical marketing (eDTCA) have globalized in an era of free and open information exchange. Yet, the unregulated expansion of eDTCA has resulted in unaddressed global public health threats. Specifically, illicit online pharmacies are engaged in the sale of purportedly safe, legitimate product that may in fact be counterfeit or substandard. These cybercriminal actors exploit available eDTCA mediums over the Internet to market their suspect products globally. Despite these risks, a detailed assessment of the public health, patient safety, and cybersecurity threats and governance mechanisms to address them has not been conducted. Discussion Illicit online pharmacies represent a significant global public health and patient safety risk. Existing governance mechanisms are insufficient and include lack of adequate adoption in national regulation, ineffective voluntary governance mechanisms, and uneven global law enforcement efforts that have allowed proliferation of these cybercriminals on the web. In order to effectively address this multistakeholder threat, inclusive global governance strategies that engage the information technology, law enforcement and public health sectors should be established. Summary Effective global “eHealth Governance” focused on cybercrime is needed in order to effectively combat illicit online pharmacies. This includes building upon existing Internet governance structures and coordinating partnership between the UN Office of Drugs and Crime that leads the global fight against transnational organized crime and the Internet Governance Forum that is shaping the future of Internet governance. Through a UNODC-IGF governance mechanism, investigation, detection and coordination of activities against illicit online pharmacies and their misuse of eDTCA can commence. PMID:24131576

  1. Channel profiles around Himalayan river anticlines: Constraints on their formation from digital elevation model analysis

    NASA Astrophysics Data System (ADS)

    Robl, JöRg; Stüwe, Kurt; Hergarten, Stefan

    2008-06-01

    We present a comparison between measured and numerically modeled channel profiles of rivers in two important drainage basins of Central Nepal: the Kali-Gandaki and the Arun drainage basins. Modeled channel profiles are based on a simple stream power approach using best fit exponents defining the nonlinearities in the relative contributions of local channel gradient and water flux to erosion rate. Our analysis of the stream power in the whole river network confirms the work of other authors that a 50- to 80-km-wide zone, roughly corresponding to the High Himalayan topography, is subjected to rapid rock uplift. We suggest a model where the uplift of this zone is driven by erosion and isostatic response, so that centers of maximum uplift are located within the main channels of the north-south draining rivers. We also suggest that the rate of uplift slows down with increasing distance to the main channels. Such a spatial distribution of the uplift leads ultimately to the formation of river anticlines as observed along all major Himalayan rivers. We propose that the formation of river anticlines along south draining Himalayan rivers was accelerated by a sudden increase of the drainage area and discharge when the rivers captured orogen-parallel drainages on the north side of the range. This may follow successive headward cutting into the Tibetan Plateau. The model is confirmed by differences between main channels and east-west running tributaries. Time-dependent numerical models predict that capture events cause strongly elevated erosion rates in the main channel.

  2. Implications of Dynamic Occupancy, Binding Kinetics, and Channel Gating Kinetics for hERG Blocker Safety Assessment and Mitigation.

    PubMed

    Pearlstein, Robert A; MacCannell, K Andrew; Erdemli, Gül; Yeola, Sarita; Helmlinger, Gabriel; Hu, Qi-Ying; Farid, Ramy; Egan, William; Whitebread, Steven; Springer, Clayton; Beck, Jeremy; Wang, Hao-Ran; Maciejewski, Mateusz; Urban, Laszlo; Duca, José S

    2016-01-01

    Blockade of the hERG potassium channel prolongs the ventricular action potential (AP) and QT interval, and triggers early after depolarizations (EADs) and torsade de pointes (TdP) arrhythmia. Opinions differ as to the causal relationship between hERG blockade and TdP, the relative weighting of other contributing factors, definitive metrics of preclinical proarrhythmicity, and the true safety margin in humans. Here, we have used in silico techniques to characterize the effects of channel gating and binding kinetics on hERG occupancy, and of blockade on the human ventricular AP. Gating effects differ for compounds that are sterically compatible with closed channels (becoming trapped in deactivated channels) versus those that are incompatible with the closed/closing state, and expelled during deactivation. Occupancies of trappable blockers build to equilibrium levels, whereas those of non-trappable blockers build and decay during each AP cycle. Occupancies of ~83% (non-trappable) versus ~63% (trappable) of open/inactive channels caused EADs in our AP simulations. Overall, we conclude that hERG occupancy at therapeutic exposure levels may be tolerated for nontrappable, but not trappable blockers capable of building to the proarrhythmic occupancy level. Furthermore, the widely used Redfern safety index may be biased toward trappable blockers, overestimating the exposure-IC50 separation in nontrappable cases. PMID:26975508

  3. The design of a digital voice data compression technique for orbiter voice channels

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Voice bandwidth compression techniques were investigated to anticipate link margin difficulties in the shuttle S-band communication system. It was felt that by reducing the data rate on each voice channel from the baseline 24 (or 32) Kbps to 8 Kbps, additional margin could be obtained. The feasibility of such an alternate voice transmission system was studied. Several factors of prime importance that were addressed are: (1) achieving high quality voice at 8 Kbps; (2) performance in the presence of the anticipated shuttle cabin environmental noise; (3) performance in the presence of the anticipated channel error statistics; and (4) minimal increase in size, weight, and power over the current baseline voice processor.

  4. Current research results on the technical basis for environmental qualification of safety-related digital I and C systems

    SciTech Connect

    Korsah, K.; Ewing, P.D.; Kercel, S.; Wood, R.T.; Hassan, M.; Tanaka, T.; Antonescu, C.

    1998-04-01

    This paper presents results to date of an NRC-sponsored confirmatory research program initiated at three national laboratories to address environmental compatibility/qualification concerns associated with the use of microprocessor-based safety-related instrumentation and control (I and C) systems in nuclear power plants. The research approach involved evaluating existing military and industrial guidance, identifying the most significant environmental stressors and, for advanced I and C systems in a nuclear power plant, investigating the likely failure modes--both at the integrated circuit and system level--for digital technologies under varying levels of environmental stress (such as smoke exposure and electromagnetic and radio-frequency interference). The insights gained from these studies are being used to recommend appropriate methods for qualifying safety-related digital equipment in nuclear power plants.

  5. Get in the Loop: Fibre Channel, SSA, and Ultra SCSI Connect the Digital Studio.

    ERIC Educational Resources Information Center

    Sauer, Jeff

    1997-01-01

    Removable hard drives and Ethernet are common ways to move data around the media studio, but new protocols allow multiple computers to share an array on one bus. Examines shared storage configurations using fibre channel arbitrated loop (FC-AL) and serial storage architecture (SSA), both serial storage solutions, as well as on small computer…

  6. Optimization of a digital lock-in algorithm with a square-wave reference for frequency-divided multi-channel sensor signal detection

    NASA Astrophysics Data System (ADS)

    Zhang, Shengzhao; Li, Gang; Lin, Ling; Zhao, Jing

    2016-08-01

    A digital lock-in detection technique is commonly used to measure the amplitude and phase of a selected frequency signal. A technique that uses a square wave as the reference signal has an advantage over the one using a sinusoidal wave due to its easier implementation and higher computational efficiency. However, demodulating multiple-frequency composite signals using square wave reference may result in interference between channels. To avoid interference between channels and reduce the computational complexity, we modify the calculations and determine the optimal parameter settings of the low-pass filter and carrier frequency, as detailed in this paper. The results of our analysis show that when the length of the average filter and carrier frequencies are properly set, the interference between the channels is removed. This optimization produces the digital lock-in detection suitable for measuring multi-channel sensor signals.

  7. Optimization of a digital lock-in algorithm with a square-wave reference for frequency-divided multi-channel sensor signal detection.

    PubMed

    Zhang, Shengzhao; Li, Gang; Lin, Ling; Zhao, Jing

    2016-08-01

    A digital lock-in detection technique is commonly used to measure the amplitude and phase of a selected frequency signal. A technique that uses a square wave as the reference signal has an advantage over the one using a sinusoidal wave due to its easier implementation and higher computational efficiency. However, demodulating multiple-frequency composite signals using square wave reference may result in interference between channels. To avoid interference between channels and reduce the computational complexity, we modify the calculations and determine the optimal parameter settings of the low-pass filter and carrier frequency, as detailed in this paper. The results of our analysis show that when the length of the average filter and carrier frequencies are properly set, the interference between the channels is removed. This optimization produces the digital lock-in detection suitable for measuring multi-channel sensor signals. PMID:27587155

  8. A source-channel coding approach to digital image protection and self-recovery.

    PubMed

    Sarreshtedari, Saeed; Akhaee, Mohammad Ali

    2015-07-01

    Watermarking algorithms have been widely applied to the field of image forensics recently. One of these very forensic applications is the protection of images against tampering. For this purpose, we need to design a watermarking algorithm fulfilling two purposes in case of image tampering: 1) detecting the tampered area of the received image and 2) recovering the lost information in the tampered zones. State-of-the-art techniques accomplish these tasks using watermarks consisting of check bits and reference bits. Check bits are used for tampering detection, whereas reference bits carry information about the whole image. The problem of recovering the lost reference bits still stands. This paper is aimed at showing that having the tampering location known, image tampering can be modeled and dealt with as an erasure error. Therefore, an appropriate design of channel code can protect the reference bits against tampering. In the present proposed method, the total watermark bit-budget is dedicated to three groups: 1) source encoder output bits; 2) channel code parity bits; and 3) check bits. In watermark embedding phase, the original image is source coded and the output bit stream is protected using appropriate channel encoder. For image recovery, erasure locations detected by check bits help channel erasure decoder to retrieve the original source encoded image. Experimental results show that our proposed scheme significantly outperforms recent techniques in terms of image quality for both watermarked and recovered image. The watermarked image quality gain is achieved through spending less bit-budget on watermark, while image recovery quality is considerably improved as a consequence of consistent performance of designed source and channel codes. PMID:25807568

  9. A four channel time-to-digital converter ASIC with in-built calibration and SPI interface

    NASA Astrophysics Data System (ADS)

    Hari Prasad, K.; Sukhwani, Menka; Saxena, Pooja; Chandratre, V. B.; Pithawa, C. K.

    2014-02-01

    A design of high resolution, wide dynamic range Time-to-Digital Converter (TDC) ASIC, implemented in 0.35 μm commercial CMOS technology is presented. The ASIC features four channel TDC with an in-built calibration and Serial Peripheral Interconnect (SPI) slave interface. The TDC is based on the vernier ring oscillator method in order to achieve both high resolution and wide dynamic range. This TDC ASIC is tested and found to have resolution of 127 ps (LSB), dynamic range of 1.8 μs and precision (σ) of 74 ps. The measured values of differential non-linearity (DNL) and integral non-linearity (INL) are 350 ps and 300 ps respectively.

  10. Use of 64 kbits/s digital channel for image transmission: Using low scan two-way video

    NASA Astrophysics Data System (ADS)

    Rahko, K.; Hongyan, L.; Kley, M.; Peuhkuri, M.; Rahko, M.

    1993-09-01

    At the seminar 'Competition in Telecommunications in Finland' on September 3rd, 1993, a test of two-way transferring an image by using 64 kbits/s digital channel was carried out. With the help of the Helsinki Telephone Company, a portrait was transferred to the lecture hall by using Vistacom Videophones, Nokia and Siemens ISDN exchange, as well as Nokia's and Siemens' user terminal equipment. It was shown on a screen through a video projector, so all visitors could see it. For human factors in telecommunications studies, every attendee was asked to give comments about the transferring quality. The report presents the results of the survey and a brief assessment of the technology.

  11. Integrated source and channel encoded digital communication system design study. [for space shuttles

    NASA Technical Reports Server (NTRS)

    Huth, G. K.

    1976-01-01

    The results of several studies Space Shuttle communication system are summarized. These tasks can be divided into the following categories: (1) phase multiplexing for two- and three-channel data transmission, (2) effects of phase noise on the performance of coherent communication links, (3) analysis of command system performance, (4) error correcting code tradeoffs, (5) signal detection and angular search procedure for the shuttle Ku-band communication system, and (6) false lock performance of Costas loop receivers.

  12. Digital Interface Board to Control Phase and Amplitude of Four Channels

    NASA Technical Reports Server (NTRS)

    Smith, Amy E.; Cook, Brian M.; Khan, Abdur R.; Lux, James P.

    2011-01-01

    An increasing number of parts are designed with digital control interfaces, including phase shifters and variable attenuators. When designing an antenna array in which each antenna has independent amplitude and phase control, the number of digital control lines that must be set simultaneously can grow very large. Use of a parallel interface would require separate line drivers, more parts, and thus additional failure points. A convenient form of control where single-phase shifters or attenuators could be set or the whole set could be programmed with an update rate of 100 Hz is needed to solve this problem. A digital interface board with a field-programmable gate array (FPGA) can simultaneously control an essentially arbitrary number of digital control lines with a serial command interface requiring only three wires. A small set of short, high-level commands provides a simple programming interface for an external controller. Parity bits are used to validate the control commands. Output timing is controlled within the FPGA to allow for rapid update rates of the phase shifters and attenuators. This technology has been used to set and monitor eight 5-bit control signals via a serial UART (universal asynchronous receiver/transmitter) interface. The digital interface board controls the phase and amplitude of the signals for each element in the array. A host computer running Agilent VEE sends commands via serial UART connection to a Xilinx VirtexII FPGA. The commands are decoded, and either outputs are set or telemetry data is sent back to the host computer describing the status and the current phase and amplitude settings. This technology is an integral part of a closed-loop system in which the angle of arrival of an X-band uplink signal is detected and the appropriate phase shifts are applied to the Ka-band downlink signal to electronically steer the array back in the direction of the uplink signal. It will also be used in the non-beam-steering case to compensate for

  13. High speed, multi-channel, user programmable digital data acquisition system.

    SciTech Connect

    Sabourov, Konstantin; Hennig, Wolfgang; Walby, Mark

    2013-11-18

    As applications for radiation detection become more demanding, and in turn improvements are made in the technology of radiation detection, there is a need for high speed digital detector readout electronics matching these improvements. Specifically, full control over the on-line processing resources of modern digital electronics is desirable so that researchers can develop custom algorithms for special applications.In the proposed effort, the 500 MHz digital readout electronics previously developed by our company will be redesigned to allow user access to the on-line processing resources. In Phase I, the division of online processing into vendor and user firmware sections has been studied on existing hardware. In Phase II, the hardware will be upgraded to better facilitate the division, and the firmware will be restructured into a robust vendor logic block (providing standard functions such as host I/O, on-board memory I/O, energy computation, MCA spectra, timestamps, waveform capture, run statistics, and triggering and timing) and a user logic block for custom algorithms (with templates and examples for frequently used functions). Investigating several options to divide online processing, it was determined that the most promising approach is to “partition” a single FPGA integrated circuit into a vendor and user section, which is supported in newer devices. The analog front end of the existing electronics proved suitable for most applications, in particular high rate measurements with germanium detectors. The design architecture for new electronics was developed, combining one of the new FPGA device with the analog front end.

  14. Channel

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03693 Channel

    This channel is located south of Iani Chaos.

    Image information: VIS instrument. Latitude -10.9N, Longitude 345.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. 33 CFR 165.1702 - Gastineau Channel, Juneau, Alaska-safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... are a safety zone: A line beginning at the Standard Oil Company Pier West Light (LLNR 3217), located... transit or navigate within the safety zone. (2) No vessels, other than a large passenger vessel...

  16. 33 CFR 165.1702 - Gastineau Channel, Juneau, Alaska-safety zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... are a safety zone: A line beginning at the Standard Oil Company Pier West Light (LLNR 3217), located... transit or navigate within the safety zone. (2) No vessels, other than a large passenger vessel...

  17. 33 CFR 165.1702 - Gastineau Channel, Juneau, Alaska-safety zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... are a safety zone: A line beginning at the Standard Oil Company Pier West Light (LLNR 3217), located... transit or navigate within the safety zone. (2) No vessels, other than a large passenger vessel...

  18. 33 CFR 165.1702 - Gastineau Channel, Juneau, Alaska-safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... are a safety zone: A line beginning at the Standard Oil Company Pier West Light (LLNR 3217), located... transit or navigate within the safety zone. (2) No vessels, other than a large passenger vessel...

  19. 33 CFR 165.1702 - Gastineau Channel, Juneau, Alaska-safety zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... are a safety zone: A line beginning at the Standard Oil Company Pier West Light (LLNR 3217), located... transit or navigate within the safety zone. (2) No vessels, other than a large passenger vessel...

  20. Design of a digital voice data compression technique for orbiter voice channels

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Candidate techniques were investigated for digital voice compression to a transmission rate of 8 kbps. Good voice quality, speaker recognition, and robustness in the presence of error bursts were considered. The technique of delayed-decision adaptive predictive coding is described and compared with conventional adaptive predictive coding. Results include a set of experimental simulations recorded on analog tape. The two FM broadcast segments produced show the delayed-decision technique to be virtually undegraded or minimally degraded at .001 and .01 Viterbi decoder bit error rates. Preliminary estimates of the hardware complexity of this technique indicate potential for implementation in space shuttle orbiters.

  1. ddpcRquant: threshold determination for single channel droplet digital PCR experiments.

    PubMed

    Trypsteen, Wim; Vynck, Matthijs; De Neve, Jan; Bonczkowski, Pawel; Kiselinova, Maja; Malatinkova, Eva; Vervisch, Karen; Thas, Olivier; Vandekerckhove, Linos; De Spiegelaere, Ward

    2015-07-01

    Digital PCR is rapidly gaining interest in the field of molecular biology for absolute quantification of nucleic acids. However, the first generation of platforms still needs careful validation and requires a specific methodology for data analysis to distinguish negative from positive signals by defining a threshold value. The currently described methods to assess droplet digital PCR (ddPCR) are based on an underlying assumption that the fluorescent signal of droplets is normally distributed. We show that this normality assumption does not likely hold true for most ddPCR runs, resulting in an erroneous threshold. We suggest a methodology that does not make any assumptions about the distribution of the fluorescence readouts. A threshold is estimated by modelling the extreme values in the negative droplet population using extreme value theory. Furthermore, the method takes shifts in baseline fluorescence between samples into account. An R implementation of our method is available, allowing automated threshold determination for absolute ddPCR quantification using a single fluorescent reporter. PMID:26022094

  2. Developing Digital Image Techniques with Low-Cost Unmanned Mobile to Monitor the Safety of Dam and Affiliated Structure

    NASA Astrophysics Data System (ADS)

    Sung, Wen-Pei; Shih, Ming-Hsiang

    2016-04-01

    Global warming phenomena are increasingly serious, the El Niño and La Niña continue to occur repeatedly, causing the irregular drought and flood problem repeatedly. Mountain form of Taiwan is steep and storage ability of rainwater is insufficient to supply the livelihood of people and usage of industry which need to rely on rainwater reservoir. Thus, to ensure the water supply and self-reliance energy supply, one of ways to keep water resource is to build reservoir. Nevertheless, Taiwan is located on Pacific seismic belt; additionally, geological conditions are not fine, over-developed in the hills lead to more natural disasters in the future. Thus, strong shakes and typhoons which caused a degree of severe landslides around dam lead to reduce catchment of dam to result in affecting the safety of dam. Otherwise, the cracks and rusts in dam, induced by the defects of material, bad construction and seismic excitation respectively, thus, the mechanics phenomena of dam and its affiliated structures with crack are probing into the cause of stress concentration, induced high crack increase rate, affect the safety and usage of dam. This research is aimed at the safety evaluation technique of dam and its affiliated structures to develop three dimensional digital image correlation techniques for monitoring the safety of dam and its affiliated structures. Namely, developing the unmanned mobile on two axis of digital image correlation method is to detect the digital images from geometric scanning techniques for dam structure. This developed technique combined with Unmanned Aerial Vehicle (UAV) to develop the near filed scanning and monitoring techniques for local deformation and cracks on dam and its affiliated structures.

  3. Digital multi-channel stabilization of four-mode phase-sensitive parametric multicasting.

    PubMed

    Liu, Lan; Tong, Zhi; Wiberg, Andreas O J; Kuo, Bill P P; Myslivets, Evgeny; Alic, Nikola; Radic, Stojan

    2014-07-28

    Stable four-mode phase-sensitive (4MPS) process was investigated as a means to enhance two-pump driven parametric multicasting conversion efficiency (CE) and signal to noise ratio (SNR). Instability of multi-beam, phase sensitive (PS) device that inherently behaves as an interferometer, with output subject to ambient induced fluctuations, was addressed theoretically and experimentally. A new stabilization technique that controls phases of three input waves of the 4MPS multicaster and maximizes CE was developed and described. Stabilization relies on digital phase-locked loop (DPLL) specifically was developed to control pump phases to guarantee stable 4MPS operation that is independent of environmental fluctuations. The technique also controls a single (signal) input phase to optimize the PS-induced improvement of the CE and SNR. The new, continuous-operation DPLL has allowed for fully stabilized PS parametric broadband multicasting, demonstrating CE improvement over 20 signal copies in excess of 10 dB. PMID:25089457

  4. FMCW channel sounder with digital processing for measuring the coherence of wideband HF radio links

    NASA Astrophysics Data System (ADS)

    Salous, S.

    1986-08-01

    Multipath propagation, and in particular, the interference between the ordinary and the extraordinary waves, places a fundamental constraint on the performance of wideband HF skywave radio links. Furthermore, the dispersive nature of ionospheric propagation causes phase nonlinearity and hence distortion of narrow pulses. In this paper, an FMCW wideband sounder built for the purposes of characterizing the channel is described. Spectral analysis of the audio output of the sounder via the FFT algorithm is shown to permit measurement of thef amplitude/frequency function, the polarization bandwidth, the fade rate, the fade depth and the distortion of a narrow pulse, all for a desired isolated ionospheric propagation mode. The sounder was used to collect data over an oblique path in the UK. The results of applying the FFT processing technique to the experimental data are presented.

  5. Single-channel 40 Gbit/s digital coherent QAM quantum noise stream cipher transmission over 480 km.

    PubMed

    Yoshida, Masato; Hirooka, Toshihiko; Kasai, Keisuke; Nakazawa, Masataka

    2016-01-11

    We demonstrate the first 40 Gbit/s single-channel polarization-multiplexed, 5 Gsymbol/s, 16 QAM quantum noise stream cipher (QNSC) transmission over 480 km by incorporating ASE quantum noise from EDFAs as well as the quantum shot noise of the coherent state with multiple photons for the random masking of data. By using a multi-bit encoded scheme and digital coherent transmission techniques, secure optical communication with a record data capacity and transmission distance has been successfully realized. In this system, the signal level received by Eve is hidden by both the amplitude and the phase noise. The highest number of masked signals, 7.5 x 10(4), was achieved by using a QAM scheme with FEC, which makes it possible to reduce the output power from the transmitter while maintaining an error free condition for Bob. We have newly measured the noise distribution around I and Q encrypted data and shown experimentally with a data size of as large as 2(25) that the noise has a Gaussian distribution with no correlations. This distribution is suitable for the random masking of data. PMID:26832295

  6. 77 FR 29899 - Safety Zone; International Special Operations Forces Week Capability Exercise, Seddon Channel...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Week Capability Exercise, Seddon Channel, Tampa, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final... Operations Forces Week Capability Exercise. The exercise is scheduled to take place on Tuesday, May 22, 2012... associated with airborne and waterborne activities occurring during the exercise. Persons and vessels...

  7. 77 FR 68718 - Safety Zone for Fireworks Display, Upper Potomac River, Alexandria Channel; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-16

    .... SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). ] 4. Public Meeting..., Alexandria Channel; Washington, DC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking....

  8. Safety of aquaflor (florfenicol, 50% type a medicated article), administered in feed to channel catfish, Ictalurus punctatus

    USGS Publications Warehouse

    Gaikowski, Mark P.; Wolf, Jeffery C.; Endris, Richard G.; Gingerich, William H.

    2003-01-01

    Aquaflor, a feed premix containing the broad spectrum antibacterial agent florfenicol (50% w/w), is being developed for use to control enteric septicemia (ESC) in channel catfish Ictalurus punctatus caused by the gram-negative enterobacterium Edwardsiella ictaluri. The recommended dose of Aquaflor to control ESC is 10 mg/kg body weight (BW)/day for 10 days. The study objective was to determine the safety of Aquaflor administered in feed to channel catfish at doses of 0 (control), 10, 30, and 50 mg/kg BW/day for 20 consecutive days. Parameters evaluated included daily mortality, behavioral (appetite, distribution, flight/fright response), and water chemistry observations, initial and terminal weight measurements, and gross and microscopic pathology. Medicated feed consumption was 67-86% of target with group mean doses of 8.5 mg/kg BW/day, 24.6 mg/kg BW/day, and 34.9 mg/kg BW/day. There were no mortalities or clinically observable changes noted at any of the dose levels tested. Aquaflor-related changes were limited to the food consumption and histopathology data. Although Aquaflor-related decreased feed consumption was noted in the 30 and 50 mg/kg BW/day groups, there were no differences in fish growth among the treatment groups. Aquaflor-related histopathology findings were limited to a histomorphologically evident dose-dependent decrease in hematopoietic/lymphopoietic tissue in the anterior kidneys, posterior kidneys, and spleens of channel catfish.

  9. Safety of Aquaflor (Florfenicol, 50% Type A Medicated Article), Administered in Feed to Channel Catfish, Ictalurus punctatus

    USGS Publications Warehouse

    Gaikowski, M.P.; Wolf, J.C.; Endris, R.G.; Gingerich, W.H.

    2003-01-01

    Aquaflor, a feed premix containing the broad spectrum antibacterial agent florfenicol (50% w/w), is being developed for use to control enteric septicemia (ESC) in channel catfish Ictalurus punctatus caused by the gram-negative enterobacterium Edwardsiella ictaluri. The recommended dose of Aquaflor to control ESC is 10 mg/kg body weight (BW)/day for 10 days. The study objective was to determine the safety of Aquaflor administered in feed to channel catfish at doses of 0 (control), 10, 30, and 50 mg/kg BW/day for 20 consecutive days. Parameters evaluated included daily mortality, behavioral (appetite, distribution, flight/fright response), and water chemistry observations, initial and terminal weight measurements, and gross and microscopic pathology. Medicated feed consumption was 67-86% of target with group mean doses of 8.5 mg/kg BW/day, 24.6 mg/kg BW/day, and 34.9 mg/kg BW/day. There were no mortalities or clinically observable changes noted at any of the dose levels tested. Aquaflor-related changes were limited to the food consumption and histopathology data. Although Aquaflor-related decreased feed consumption was noted in the 30 and 50 mg/kg BW/day groups, there were no differences in fish growth among the treatment groups. Aquaflor-related histopathology findings were limited to a histomorphologically evident dose-dependent decrease in hematopoietic/lymphopoietic tissue in the anterior kidneys, posterior kidneys, and spleens of channel catfish.

  10. A comparison of collision-based and conflict-based safety evaluations: the case of right-turn smart channels.

    PubMed

    Sacchi, Emanuele; Sayed, Tarek; deLeur, Paul

    2013-10-01

    This study presents the results of a collision-based full Bayes (FB) before-after (BA) safety evaluation of a newly proposed design for channelized right-turn lanes. The design which is termed "Smart Channels" decreases the angle of the channelized right-turn to approximately 70°. Its implementation is usually advocated to afford drivers a better view of the traffic stream they are to merge with and to allow also for safer pedestrian crossing. The evaluation used data for three treatment intersections and several comparison sites in the city of Penticton, British Columbia. The evaluation utilized FB univariate and multivariate linear intervention models with multiple regression links representing time, treatment, and interaction effects as well as the traffic volumes effects. As well, the models were extended to incorporate random parameters to account for the correlation between sites within comparison-treatment pairs. The results showed that the implementation of the right-turn treatment has resulted in a considerable reduction in the severity and frequency of collisions. Another objective of the paper was to compare the results of the collision-based evaluation with the results of a traffic conflict-based evaluation of the same treatment intersections. The comparison showed remarkable similarity between the overall and the location specific reductions in conflicts and collisions which provides support for using traffic conflicts in BA studies. The results also provide positive empirical evidence that can support the validity of traffic conflict techniques. PMID:23831452

  11. L-Band Digital Aeronautical Communications System Engineering - Initial Safety and Security Risk Assessment and Mitigation

    NASA Technical Reports Server (NTRS)

    Zelkin, Natalie; Henriksen, Stephen

    2011-01-01

    This document is being provided as part of ITT's NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: "New ATM Requirements--Future Communications, C-Band and L-Band Communications Standard Development." ITT has completed a safety hazard analysis providing a preliminary safety assessment for the proposed L-band (960 to 1164 MHz) terrestrial en route communications system. The assessment was performed following the guidelines outlined in the Federal Aviation Administration Safety Risk Management Guidance for System Acquisitions document. The safety analysis did not identify any hazards with an unacceptable risk, though a number of hazards with a medium risk were documented. This effort represents a preliminary safety hazard analysis and notes the triggers for risk reassessment. A detailed safety hazards analysis is recommended as a follow-on activity to assess particular components of the L-band communication system after the technology is chosen and system rollout timing is determined. The security risk analysis resulted in identifying main security threats to the proposed system as well as noting additional threats recommended for a future security analysis conducted at a later stage in the system development process. The document discusses various security controls, including those suggested in the COCR Version 2.0.

  12. 33 CFR 165.1706 - Gastineau Channel, Juneau, Alaska-Safety Zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... at 58°17′41″ N, 134°24′22″ W used to conduct fireworks displays. (b) Effective date. The safety zone becomes effective on July 3 each year at 10 p.m. ADT. It terminates at the conclusion of the fireworks... Port. If the fireworks display is postponed because of inclement weather, the date and duration of...

  13. 33 CFR 165.1706 - Gastineau Channel, Juneau, Alaska-Safety Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... at 58°17′41″ N, 134°24′22″ W used to conduct fireworks displays. (b) Effective date. The safety zone becomes effective on July 3 each year at 10 p.m. ADT. It terminates at the conclusion of the fireworks... Port. If the fireworks display is postponed because of inclement weather, the date and duration of...

  14. 33 CFR 165.1706 - Gastineau Channel, Juneau, Alaska-Safety Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... at 58°17′41″ N, 134°24′22″ W used to conduct fireworks displays. (b) Effective date. The safety zone becomes effective on July 3 each year at 10 p.m. ADT. It terminates at the conclusion of the fireworks... Port. If the fireworks display is postponed because of inclement weather, the date and duration of...

  15. 33 CFR 165.1706 - Gastineau Channel, Juneau, Alaska-Safety Zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... at 58°17′41″ N, 134°24′22″ W used to conduct fireworks displays. (b) Effective date. The safety zone becomes effective on July 3 each year at 10 p.m. ADT. It terminates at the conclusion of the fireworks... Port. If the fireworks display is postponed because of inclement weather, the date and duration of...

  16. 33 CFR 165.1706 - Gastineau Channel, Juneau, Alaska-Safety Zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... at 58°17′41″ N, 134°24′22″ W used to conduct fireworks displays. (b) Effective date. The safety zone becomes effective on July 3 each year at 10 p.m. ADT. It terminates at the conclusion of the fireworks... Port. If the fireworks display is postponed because of inclement weather, the date and duration of...

  17. Source-Coupled, N-Channel, JFET-Based Digital Logic Gate Structure Using Resistive Level Shifters

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J.

    2011-01-01

    A circuit topography is used to create usable, digital logic gates using N (negatively doped) channel junction field effect transistors (JFETs), load resistors, level shifting resistors, and supply rails whose values are based on the DC parametric distributions of these JFETs. This method has direct application to the current state-of-the-art in high-temperature (300 to 500 C and higher) silicon carbide (SiC) device production, and defines an adaptation to the logic gate described in U.S. Patent 7,688,117 in that, by removing the level shifter from the output of the gate structure described in the patent (and applying it to the input of the same gate), a source-coupled gate topography is created. This structure allows for the construction AND/OR (sum of products) arrays that use far fewer transistors and resistors than the same array as constructed from the gates described in the aforementioned patent. This plays a central role when large multiplexer constructs are necessary; for example, as in the construction of memory. This innovation moves the resistive level shifter from the output of the basic gate structure to the front as if the input is now configured as what would be the output of the preceding gate, wherein the output is the two level shifting resistors. The output of this innovation can now be realized as the lone follower transistor with its source node as the gate output. Additionally, one may leave intact the resistive level shifter on the new gate topography. A source-coupled to direct-coupled logic translator will be the result.

  18. A 12-bit, 1 MS/s SAR-ADC for a CZT-based multi-channel gamma-ray imager using a new digital calibration method

    NASA Astrophysics Data System (ADS)

    Liu, W.; Wei, T.; Yang, L.; Hu, Y.

    2016-03-01

    The successive approximation register-analog to digital converter (SAR-ADC) is widely used in the CdZnTe-based gamma-ray imager because of its outstanding characteristics of low power consumption, relatively high resolution, and small die size. This study proposes a digital bit-by-bit calibration method using an input ramp signal to further improve the conversion precision and power consumption of an SAR-ADC. The proposed method is based on the sub-radix-2 redundant architecture and the perturbation technique. The proposed calibration algorithm is simpler, more stable, and faster than traditional approaches. The prototype chip of the 12-bit, 1 MS/s radiation-hardened SAR-ADC has been designed and fabricated using the TSMC 0.35 μm 2P4M CMOS process. This SAR-ADC consumes 3 mW power and occupies a core area of 856× 802μm2. The digital bit-by-bit calibration algorithm is implemented via MATLAB for testing flexibility. The effective number of bits for this digitally calibrated SAR-ADC reaches 11.77 bits. The converter exhibits high conversion precision, low power consumption, and radiation-hardened design. Therefore, this SAR-ADC is suitable for multi-channel gamma-ray imager applications.

  19. Evaluation of correlative coding and DP-16QAM n-channel 112Gbit/s coherent transmission: digital non-linear compensation perspective.

    PubMed

    Asif, Rameez; Lin, Chien-Yu; Holtmannspoetter, Michael; Schmauss, Bernhard

    2013-01-14

    We numerically report on the complexity reduction of digital backward propagation (DBP) by utilizing correlative encoded transmission (dual-polarization quadrature duobinary) at a bit-rate of 112Gbit/s over 1640km fiber link. The single channel (N=1) and multi-channel (N=10) transmission performances are compared in this paper. In case of multi-channel system, 10 transmitters are multiplexed with 25GHz channel spacing. The fiber link consists of Large A(eff) Pure-Silica core fiber with 20 spans of 82km each. No in-line optical dispersion compensator is employed in the link. The system performances are evaluated by monitoring the bit-error-ratio and the forward error correction limit corresponds to bit-error-ratio of 3.8×10(-3). The DBP algorithm is implemented after the coherent detection and is based on the logarithmic step-size based split-step Fourier method. The results depict that dual-polarization quadrature duobinary can be used to transmit 112Gbit/s signals with an spectral efficiency of 4-b/s/Hz, but at the same time has a higher tolerance to nonlinear transmission impairments. By utilizing dual-polarization quadrature duobinary modulation, comparative system performance with respect to dual-polarization 16-quadrature amplitude modulation transmission can be achieved with 60% less computations and with a step-size of 205km. PMID:23388970

  20. Safety.

    ERIC Educational Resources Information Center

    Education in Science, 1996

    1996-01-01

    Discusses safety issues in science, including: allergic reactions to peanuts used in experiments; explosions in lead/acid batteries; and inspection of pressure vessels, such as pressure cookers or model steam engines. (MKR)

  1. A new classifier-based strategy for in-silico ion-channel cardiac drug safety assessment.

    PubMed

    Mistry, Hitesh B; Davies, Mark R; Di Veroli, Giovanni Y

    2015-01-01

    There is currently a strong interest in using high-throughput in-vitro ion-channel screening data to make predictions regarding the cardiac toxicity potential of a new compound in both animal and human studies. A recent FDA think tank encourages the use of biophysical mathematical models of cardiac myocytes for this prediction task. However, it remains unclear whether this approach is the most appropriate. Here we examine five literature data-sets that have been used to support the use of four different biophysical models and one statistical model for predicting cardiac toxicity in numerous species using various endpoints. We propose a simple model that represents the balance between repolarisation and depolarisation forces and compare the predictive power of the model against the original results (leave-one-out cross-validation). Our model showed equivalent performance when compared to the four biophysical models and one statistical model. We therefore conclude that this approach should be further investigated in the context of early cardiac safety screening when in-vitro potency data is generated. PMID:25852560

  2. A 72 channel 125 MSPS analog-to-digital converter module for drift chamber readout for the GlueX detector

    SciTech Connect

    G. visser, D. Abbot, F. Barbosa, C. Cuevas, H. Dong, E. Jastrzembski, B. Moffitt, B. Raydo

    2011-06-01

    We have developed a very high channel density custom A/D converter module for the drift chamber readout requirements of the Glue-X detector at Jefferson Lab Hall-D. This 6U VME64× module has 72 channels, including a low noise differential line receiver, cable frequency response equalization, and signal shaping with a 5th order filter. The signals are digitized at 125 MSPS with an assembly option for either 12 or 14 bit resolution (GlueX will use 12 bit). The digitized data is written continuously to a circular buffer, with an independent read port and pipelined readout path able to extract potentially overlapping signal records at a 200 kHz trigger rate without deadtime. The extracted data is zero suppressed and may be further processed on-board to reduce the data volume, and is then assembled into event records and event block records. Up to 1 MB of output data is buffered on-board and available for readout via 2eSST at up to 320 MByte/s.

  3. Facial protection conferred by cycle safety helmets: use of digitized image processing to develop a new nondestructive test.

    PubMed

    Harrison, M; Shepherd, J P

    1997-07-01

    Cycle safety helmets are designed to prevent head injury. Although most commercially available helmets conform to one of several national and international standards, individual designs differ widely, particularly in relation to face coverage. A method was developed to assess the potential for the differing designs to protect the face from injury. A nonimpact test was assessed, using digitized image-processing software (Digithurst Ltd.) to measure the shadow cast by a helmet rim under a collimated plane light source onto the face of a mannequin headform. Twelve helmet designs available internationally were tested and ranked with respect to the direct protection conferred (area of the face directly covered by the helmet) and indirect protection (area of the face shaded). The three highest-ranking helmets for direct protection (Rosebank Stackhat, Asphalt Warrior, and Lazer Voyager) also ranked the highest for indirect protection. These helmets were more inferiorly extended and were of a more bulky construction. It was concluded that the dimensions of cycle helmets in relation to face coverage are crucial in influencing the extent to which facial protection is conferred. International test standards need urgent revision to ensure that face coverage is optimized. Lower-face protection could be achieved through incorporation of a lower-face bar to cycle helmets. PMID:9253912

  4. Single channel 112Gbit/sec PAM4 at 56Gbaud with digital signal processing for data centers applications.

    PubMed

    Sadot, Dan; Dorman, G; Gorshtein, Albert; Sonkin, Eduard; Vidal, Or

    2015-01-26

    112Gbit/sec DSP-based single channel transmission of PAM4 at 56Gbaud over 15GHz of effective analog bandwidth is experimentally demonstrated. The DSP enables use of mature 25G optoelectronics for 2-10km datacenter intra-connections, and 8Tbit/sec over 80km interconnections between data centers. PMID:25835858

  5. 33 CFR 165.731 - Safety/Security Zone: Cumberland Sound, Georgia and St. Marys River Entrance Channel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Florida. (3) The general regulations governing safety and security zones contained in 33 CFR 165.23 and... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Safety/Security Zone: Cumberland... Seventh Coast Guard District § 165.731 Safety/Security Zone: Cumberland Sound, Georgia and St. Marys...

  6. Physical-gap-channel graphene field effect transistor with high on/off current ratio for digital logic applications

    NASA Astrophysics Data System (ADS)

    Hun Mun, Jeong; Jin Cho, Byung

    2012-10-01

    We propose and analyze an approach to secure a high on/off current ratio in a graphene field effect transistor (FET) by introducing a physical gap along the channel rather than by attempting to open the energy bandgap of graphene. The device simulation results of the newly proposed device structure reveal highly suppressed off-state current of ˜10-9 A/μm, an on/off current ratio of more than seven orders of magnitude, and a subthreshold slope of 2.23 mV/decade more than a 20-fold reduction relative to the theoretical limitation of conventional metal-oxide-semiconductor FETs.

  7. 78 FR 17094 - Safety Zone; 2013 Naval Air Station Key West Air Spectacular, Boca Chica Channel; Boca Chica, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... Security FR Federal Register NPRM Notice of Proposed Rulemaking A. Regulatory History and Information The... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2013 Naval Air Station Key West Air... in Boca Chica, Florida, during the 2013 Naval Air Station Key West Air Spectacular. The safety...

  8. Active cancellation of transformer noise: Volume 1, Overview; Volume 2, Computer simulation; Volume 3, Eight-channel digital controller. Final report

    SciTech Connect

    Angevine, O.; Craig, S.E.

    1995-10-01

    The object of this research was to investigate the attenuation of substation transformer hum produced by an active control system. Active cancellation is achieved by the generation of a replica of the original sound which is added to the original in reversed phase. Active noise control offers an alternative to large barriers for attenuating transformer noise. Barriers do not work well at the low frequencies of transformer hum and noise reductions greater than 12 dB are generally not practical. In contrast, active cancellation works best at low frequencies. This project is a follow-on to work done under the sponsorship of the Niagara Mohawk Power Company where the goal was to produce global cancellation. That project proved the feasibility of active cancellation but the analog, controller used proved to be increasingly unstable as the number of control channels was increased. The objective of the project reported here was to investigate the attenuation of the transformer hum over 60{degrees} of azimuth employing a number of secondary sound sources forming an ``active wall`` on one side of the transformer. An active control system was developed, centered around a multichannel programmable adaptive controller, implemented digitally and based on a microcomputer. It is inherently stable and cannot ``run away`` like conventional feed-back devices.

  9. A 515 nW, 0-18 dB Programmable Gain Analog-to-Digital Converter for In-Channel Neural Recording Interfaces.

    PubMed

    Rodriguez-Perez, Alberto; Delgado-Restituto, Manuel; Medeiro, Fernando

    2014-06-01

    This paper presents a low-area low-power Switched-Capacitor (SC)-based Programmable-Gain Analog-to-Digital Converter (PG-ADC) suitable for in-channel neural recording applications. The PG-ADC uses a novel implementation of the binary search algorithm that is complemented with adaptive biasing techniques for power saving. It has been fabricated in a standard CMOS 130 nm technology and only occupies 0.0326 mm(2). The PG-ADC has been optimized to operate under two different sampling modes, 27 kS/s and 90 kS/s. The former is tailored for raw data conversion of neural activity, whereas the latter is used for the on-the-fly feature extraction of neural spikes. Experimental results show that, under a voltage supply of 1.2 V, the PG-ADC obtains an ENOB of 7.56 bit (8-bit output) for both sampling modes, regardless of the gain setting. The amplification gain can be programmed from 0 to 18 dB. The power consumption of the PG-ADC at 90 kS/s is 1.52 μW with a FoM of 89.49 fJ/conv, whereas at 27 kS/s it consumes 515 nW and obtains a FoM of 98.31 fJ/conv . PMID:23899652

  10. Digital and analog communication systems

    NASA Technical Reports Server (NTRS)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  11. 33 CFR 165.731 - Safety/Security Zone: Cumberland Sound, Georgia and St. Marys River Entrance Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., Florida. (3) The general regulations governing safety and security zones contained in 33 CFR 165.23 and...′17″ W; thence following the land based perimeter boundary to the point of origin. (b) A temporary... northern extent of this zone starts at the southern tip of Crab Island; lighted buoy number “1” at...

  12. 33 CFR 165.731 - Safety/Security Zone: Cumberland Sound, Georgia and St. Marys River Entrance Channel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., Florida. (3) The general regulations governing safety and security zones contained in 33 CFR 165.23 and...′17″ W; thence following the land based perimeter boundary to the point of origin. (b) A temporary... northern extent of this zone starts at the southern tip of Crab Island; lighted buoy number “1” at...

  13. 33 CFR 165.731 - Safety/Security Zone: Cumberland Sound, Georgia and St. Marys River Entrance Channel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Florida. (3) The general regulations governing safety and security zones contained in 33 CFR 165.23 and...′17″ W; thence following the land based perimeter boundary to the point of origin. (b) A temporary... northern extent of this zone starts at the southern tip of Crab Island; lighted buoy number “1” at...

  14. 33 CFR 165.731 - Safety/Security Zone: Cumberland Sound, Georgia and St. Marys River Entrance Channel.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Florida. (3) The general regulations governing safety and security zones contained in 33 CFR 165.23 and...′17″ W; thence following the land based perimeter boundary to the point of origin. (b) A temporary... northern extent of this zone starts at the southern tip of Crab Island; lighted buoy number “1” at...

  15. 28-Channel rotary transformer

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1981-01-01

    Transformer transmits power and digital data across rotating interface. Array has many parallel data channels, each with potential l megabaud data rate. Ferrite-cored transformers are spaced along rotor; airgap between them reduces crosstalk.

  16. Beyond engagement in working with children in eight Nairobi slums to address safety, security, and housing: Digital tools for policy and community dialogue.

    PubMed

    Mitchell, Claudia; Chege, Fatuma; Maina, Lucy; Rothman, Margot

    2016-01-01

    This article studies the ways in which researchers working in the area of health and social research and using participatory visual methods might extend the reach of participant-generated creations such as photos and drawings to engage community leaders and policy-makers. Framed as going 'beyond engagement', the article explores the idea of the production of researcher-led digital dialogue tools, focusing on one example, based on a series of visual arts-based workshops with children from eight slums in Nairobi addressing issues of safety, security, and well-being in relation to housing. The authors conclude that there is a need for researchers to embark upon the use of visual tools to expand the life and use of visual productions, and in particular to ensure meaningful participation of communities in social change. PMID:27132645

  17. Effectiveness and safety of oxycodone/naloxone in the management of chronic pain in patients with systemic sclerosis with recurrent digital ulcers: two case reports

    PubMed Central

    Ughi, Nicola; Crotti, Chiara; Ingegnoli, Francesca

    2016-01-01

    Digital ulcers (DUs) are a severe and frequent clinical feature of patients with systemic sclerosis (SSc). The presence of DUs may cause severe pain and often lead to impairment of patient’s functional activities and health-related quality of life. Moreover, poor patient cooperation during the wound care procedure due to pain may be associated with a negative outcome of DU healing. Therefore, pain management has a key role in patients with SSc. These two case reports describe the effectiveness and safety of oxycodone/naloxone in patients with SSc complicated by painful chronic DUs. Such a therapy has provided pain relief and consequently an increased compliance during redressing wounds. PMID:27042030

  18. Effects of Chelidonium majus extracts and major alkaloids on hERG potassium channels and on dog cardiac action potential - a safety approach.

    PubMed

    Orvos, Péter; Virág, László; Tálosi, László; Hajdú, Zsuzsanna; Csupor, Dezső; Jedlinszki, Nikoletta; Szél, Tamás; Varró, András; Hohmann, Judit

    2015-01-01

    Chelidonium majus or greater celandine is spread throughout the world, and it is a very common and frequent component of modern phytotherapy. Although C. majus contains alkaloids with remarkable physiological effect, moreover, safety pharmacology properties of this plant are not widely clarified, medications prepared from this plant are often used internally. In our study the inhibitory effects of C. majus herb extracts and alkaloids on hERG potassium current as well as on cardiac action potential were investigated. Our data show that hydroalcoholic extracts of greater celandine and its alkaloids, especially berberine, chelidonine and sanguinarine have a significant hERG potassium channel blocking effect. These extracts and alkaloids also prolong the cardiac action potential in dog ventricular muscle. Therefore these compounds may consequently delay cardiac repolarization, which may result in the prolongation of the QT interval and increase the risk of potentially fatal ventricular arrhythmias. PMID:25481375

  19. Safety Design and Mock-Up Tests on the Combustion of Hydrogen-Air Mixture in the Vertical CNS Channel of the CARR-CNS

    SciTech Connect

    Qingfeng Yu; Quanke Feng

    2006-07-01

    A two-phase thermo-siphon loop is applied to the Cold Neutron Source (CNS) of China Advanced Research Reactor (CARR). The moderator is liquid hydrogen. The two-phase thermo-siphon consists of the crescent-shape moderator cell, the moderator transfer tube, and the condenser. The hydrogen is supplied from the buffer tank to the condenser. The most characteristic point is that the cold helium gas is introduced into the helium sub-cooling system covering the moderator cell and then flows up through the tube covering the moderator transfer tube into the condenser. The helium sub-cooling system also reduces the void fraction of the liquid hydrogen and takes a role of the helium barrier for preventing air from intruding into the hydrogen system. We call the two-phase thermo-siphon the hydrogen cold system. The main part of this system is installed in the CNS channel made of 6061 aluminum alloy (6061A) of 6 mm in thickness, 270 mm in outer diameter and about 6 m in height. For confirming the safety of the CNS, the combustion tests were carried out using the hydrogen-air mixture under the conditions in which air is introduced into the tube at 1 atmosphere, and then hydrogen gas is supplied from the gas cylinder up to the test pressures. And maximum test pressure is 0.140 MPa Gauge (G). This condition includes the design accident of the CNS. The peak pressure due to combustion is 1.09 MPa, and the design strength of the CNS channel is 3 MPa. The safety of the CNS was thus verified even if the design basis accident occurs. The pressure distribution, the stress, and the displacement of the tube were also measured. (authors)

  20. Implantable digital hearing aid

    NASA Technical Reports Server (NTRS)

    Kissiah, A. M., Jr.

    1979-01-01

    Hearing aid converts analog output of microphone into digital pulses in about 10 channels of audiofrequencies. Each pulse band could be directly connected to portion of auditory nerve most sensitive to that range.

  1. Understanding the digital divide in the clinical setting: the technology knowledge gap experienced by US safety net patients during teleretinal screening.

    PubMed

    George, Sheba; Moran, Erin; Fish, Allison; Ogunyemi, Lola

    2013-01-01

    Differential access to everyday technology and healthcare amongst safety net patients is associated with low technological and health literacies, respectively. These low rates of literacy produce a complex patient "knowledge gap" that influences the effectiveness of telehealth technologies. To understand this "knowledge gap", six focus groups (2 African-American and 4 Latino) were conducted with patients who received teleretinal screenings in U.S. urban safety-net settings. Findings indicate that patients' "knowledge gap" is primarily produced at three points: (1) when patients' preexisting personal barriers to care became exacerbated in the clinical setting; (2) through encounters with technology during screening; and (3) in doctor-patient follow-up. This "knowledge gap" can produce confusion and fear, potentially affecting patients' confidence in quality of care and limiting their disease management ability. In rethinking the digital divide to include the consequences of this knowledge gap faced by patients in the clinical setting, we suggest that patient education focus on both their disease and specific telehealth technologies deployed in care delivery. PMID:23920720

  2. Digital processing of bandpass signals

    NASA Astrophysics Data System (ADS)

    Jackson, M. C.; Matthewson, P.

    Modern radar and radio systems rely on digital signal processing to enhance the quality of received signals. Prior to such processing, these signals must be converted to digital form. The historical development of signal digitization is briefly discussed in this paper and leads to a description of some current work on digital mixing. A method of directly sampling a band-limited intermediate frequency (i.f.) signal is presented, using a pair of digital mixer channels to produce complex low-pass samples of the signal envelope. The method is found to produce well matched channel outputs. Finally, the applicability of the method to radar is discussed.

  3. Educating Digital Citizens

    ERIC Educational Resources Information Center

    Tan, Thomas

    2011-01-01

    Digital citizenship is how educators, citizens, and parents can teach where the lines of cyber safety and ethics are in the interconnected online world their students will inhabit. Aside from keeping technology users safe, digital citizenship also prepares students to survive and thrive in an environment embedded with information, communication,…

  4. Digital Batteries

    NASA Astrophysics Data System (ADS)

    Hubler, Alfred

    2009-03-01

    The energy density in conventional capacitors is limited by sparking. We present nano-capacitor arrays, where - like in laser diodes and quantum wells [1] - quantization prevents dielectric breakthrough. We show that the energy density and the power/weight ratio are very high, possibly larger than in hydrogen [2]. Digital batteries are a potential clean energy source for cars, laptops, and mobile devices. The technology is related to flash drives. However, because of the high energy density, safety is a concern. Digital batteries can be easily and safely charged and discharged. In the discharged state they pose no danger. Even if a charged digital battery were to explode, it would produce no radioactive waste, no long-term radiation, and probably could be designed to produce no noxious chemicals. We discuss methodologies to prevent shorts and other measures to make digital batteries safe. [1] H. Higuraskh, A. Toriumi, F. Yamaguchi, K. Kawamura, A. Hubler, Correlation Tunnel Device, U. S. Patent No. 5,679,961 (1997) [2] Alfred Hubler, http://server10.how-why.com/blog/

  5. Digital wireless control system

    NASA Astrophysics Data System (ADS)

    Smith, R.

    1993-08-01

    The Digital Wireless Control System (DWCS) is designed to initiate high explosives safely while using a wireless remote control system. Numerous safety features have been designed into the fire control system to mitigate the hazards associated with remote initiation of high explosives. These safety features range from a telemetry (TM) fire control status system to mechanical timers and keyed power lockout switches. The environment, safety, and health (ES&H) Standard Operating Procedure (SOP) SP471970 is intended as a guide when working with the DWCS. This report describes the Digital Wireless Control System and outlines each component's theory of operation and its relationship to the system.

  6. Susceptibility of digital instrumentation and control systems to disruption by electromagnetic interference

    SciTech Connect

    Kercel, S.W.; Korsah, K.; Wood, R.T.

    1997-10-01

    The potential for disruption of safety-related digital instrumentation and control (I and C) systems by electromagnetic interference/radio-frequency interface (EMI/RFI) bears directly on the safe operation of advanced reactors. It is anticipated that the use of digital I and C equipment for safety and control functions will be substantially greater for advanced reactor designs than for current-generation nuclear reactors, which primarily use analog I and C equipment. In the absence of significant operational experience, the best available indication of the potential vulnerability of advanced digital safety systems to EMI/RFI comes from environmental testing of an experimental digital safety channel (EDSC) by the Oak Ridge National Laboratory (ORNL). The EDSC is a prototypical system representative of advanced reactor safety system designs with regard to architecture, functionality and communication protocols, and board and component fabrication technologies. An understanding of the electromagnetic environment to be expected for advanced reactors can be drawn from ORNL`s survey of ambient EMI/RFI conditions in the current generation of nuclear power plants. A summary of the results from these research efforts is reported in this paper. The lessons learned from the EMI/RFI survey and the EDSC tests contribute significantly to determining the best approach to assuring electromagnetic compatibility for the safety-related I and C systems of advanced reactors.

  7. Digital filter suppresses effects of nonstatistical noise bursts on multichannel scaler digital averaging systems

    NASA Technical Reports Server (NTRS)

    Goodman, L. S.; Salter, F. O.

    1968-01-01

    Digital filter suppresses the effects of nonstatistical noise bursts on data averaged over multichannel scaler. Interposed between the sampled channels and the digital averaging system, it uses binary logic circuitry to compare the number of counts per channel with the average number of counts per channel.

  8. A REPORT OF A STUDY OF NATIONWIDE ASSIGNMENTS OF TELEVISION CHANNELS FOR MAXIMUM SERVICE AND EFFICIENCY BY THE USE OF ELECTRONIC DIGITAL COMPUTER METHODS.

    ERIC Educational Resources Information Center

    BRONSON, VERNON; AND OTHERS

    THE OBJECTIVE OF THIS STUDY WAS TO DEMONSTRATE THE EFFICIENCY AND EFFECTIVENESS OF USING COMPUTER METHODS IN ESTABLISHING LOCATIONS OF ULTRAHIGH FREQUENCY TELEVISION BROADCASTING CENTERS. THE STUDY IS A FOLLOWUP TO A PREVIOUS SURVEY WHICH INDICATED THE NEED FOR EDUCATIONAL TELEVISION CHANNELS IN ADDITION TO THOSE AVAILABLE UNDER THE EXISTING TABLE…

  9. Meta-analysis of the efficacy and safety of adding an angiotensin receptor blocker (ARB) to a calcium channel blocker (CCB) following ineffective CCB monotherapy

    PubMed Central

    Ma, Jin; Wang, Xiao-Yan; Hu, Zhi-De; Zhou, Zhi-Rui; Schoenhagen, Paul

    2015-01-01

    Background We conducted this meta-analysis to systematically review and analyze the clinical benefits of angiotensin receptor blocker (ARB) combined with calcium channel blocker (CCB) following ineffective CCB monotherapy. Methods PubMed was searched for articles published until August 2015. Randomized controlled trials (RCTs) evaluating the clinical benefits of ARB combined with CCB following ineffective CCB monotherapy were included. The primary efficacy endpoint of the studies was normal rate of blood pressure, the secondary efficacy endpoints were the response rate and change in blood pressure from baseline. The safety endpoint of the studies was incidence of adverse events. Differences are expressed as relative risks (RRs) with 95% confidence intervals (CIs) for dichotomous outcomes and weighted mean differences (WMDs) with 95% CIs for continuous outcomes. Heterogeneity across studies was tested by using the I2 statistic. Results Seven RCTs were included and had sample sizes ranging from 185 to 1,183 subjects (total: 3,909 subjects). The pooled analysis showed that the on-target rate of hypertension treatment was significantly higher in the amlodipine + ARB group than in the amlodipine monotherapy group (RR =1.59; 95% CI, 1.31–1.91; P<0.01). The response rate of systolic blood pressure (SBP) (RR =1.28; 95% CI, 1.04–1.58; P<0.01) and diastolic blood pressure (DBP) (RR =1.27; 95% CI, 1.12–1.44; P=0.04) were significantly higher in the amlodipine + ARB group than in the amlodipine monotherapy group. The change in SBP (RR =−3.56; 95% CI, −7.76–0.63; P=0.10) and DBP (RR =−3.03; 95% CI, −6.51–0.45; P=0.09) were higher in hypertensive patients receiving amlodipine + ARB but the difference did not reach statistical significance. ARB + amlodipine treatment carried a lower risk of adverse events relative to amlodipine monotherapy (RR =0.88; 95% CI, 0.80-0.96; P<0.01). Conclusions The results of our meta-analysis demonstrate that adding an ARB to CCB

  10. Monitoring circuit for reactor safety systems

    DOEpatents

    Keefe, Donald J.

    1976-01-01

    The ratio between the output signals of a pair of reactor safety channels is monitored. When ratio falls outside of a predetermined range, it indicates that one or more of the safety channels has malfunctioned.

  11. Fractional channel multichannel analyzer

    DOEpatents

    Brackenbush, L.W.; Anderson, G.A.

    1994-08-23

    A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynchronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board. 9 figs.

  12. Fractional channel multichannel analyzer

    DOEpatents

    Brackenbush, Larry W.; Anderson, Gordon A.

    1994-01-01

    A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynscronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board.

  13. NASA SERC digital correlator projects

    NASA Technical Reports Server (NTRS)

    Canaris, John

    1992-01-01

    Interest in custom digital correlator processors is growing, in both the radio astronomy and earth sensing communities, as scientists realize that VLSI technology is available to them. This paper presents three digital correlator projects currently underway at the NASA SERC for VLSI Systems Design. The projects are as follows: a 60MHz chip for the ESTAR satellite; a 100MHz, 1024 channel autocorrelator; and a 64 MHz, VLSI system consisting of 8 32- channel complex crosscorrelators including phase rotators.

  14. Digital structural

    USGS Publications Warehouse

    Dohm, J.M.; Anderson, R.C.; Tanaka, K.L.

    1998-01-01

    Magmatic and tectonic activity have both contributed significantly to the surface geology of Mars. Digital structural mapping techniques have now been used to classify and date centers of tectonic activity in the western equatorial region. For example, our results show a center of tectonic activity at Valles Marineris, which may be associated with uplift caused by intrusion. Such evidence may help explain, in part, the development of the large troughs and associated outflow channels and chaotic terrain. We also find a local centre of tectonic activity near the source region of Warrego Valles. Here, we suggest that the valley system may have resulted largely from intrusive-related hydrothermal activity. We hope that this work, together with the current Mars Global Surveyor mission, will lead to a better understanding of the geological processes that shaped the Martian surface.

  15. The Intelsat digital communication systems

    NASA Astrophysics Data System (ADS)

    Phiel, John F., Jr.

    1990-08-01

    Intelsat international communication services resulting from the application of digital technology are summarized. Approximately 40 percent of the 140,000 terrestrial channels from the Public Switched Telephone Networks (PSTN) provided by the Intelsat network are now handled by digital systems. Digital technology for the interconnection of the PSTNs is discussed. Particular attention is paid to modulation and access techniques including the intermediate data rate (IDR) system, and the fixed and satellite switched TDMA systems. Digital compression techniques used with TDMA and IDR, such as digital speech interpolation and digital circuit multiplication, are also discussed. The Intelsat Business Service and the Intelnet Service are described in the framework of digital technology for private networks and business users. Communications for remote areas, international television services, and future opportunities through digital technologies are briefly presented.

  16. Digital Standards for NCI Websites

    Cancer.gov

    The Digital Standards for NCI Websites and Social Media provide developers and content managers guidance on the visual and content standards, as well as policies and procedures, in effect for National Cancer Institute (NCI) digital media – including traditional and mobile websites, as well as social and new media channels.

  17. High-speed digital plotter

    NASA Technical Reports Server (NTRS)

    Gray, J., Jr.

    1971-01-01

    Modified typewriter mechanism with standard logic components provides digital plot of output of multichannel analyzer. Unit plots irregular curves at approximately 14 channels per second, and smooth curves at over 25 channels per second, and is not subject to analog error or drift.

  18. Compensated digital readout family

    NASA Technical Reports Server (NTRS)

    Ludwig, David E.; Skow, Michael

    1991-01-01

    ISC has completed test on an IC which has 32 channels of amplifiers, low pass anti-aliasing filters, 13-bit analog-to-digital (A/D) converters with non-uniformity correction per channel and a digital multiplexer. The single slope class of A/D conversion is described, as are the unique variations required for incorporation of this technique for use with on-focal plane detector readout electronics. This paper describes the architecture used to implement the digital on-focal plane signal processing functions. Results from measured data on a test IC are presented for a circuit containing these functions operating at a sensor frame rate of 1000 hertz.

  19. Digital Sensor Technology

    SciTech Connect

    Thomas, Ken D.; Quinn, Edward L.; Mauck, Jerry L.; Bockhorst, Richard M.

    2015-02-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy and reliability. This paper, which refers to a final report issued in 2013, demonstrates these benefits in direct comparisons of digital and analog sensor applications. Improved accuracy results from the superior operating characteristics of digital sensors. These include improvements in sensor accuracy and drift and other related parameters which reduce total loop uncertainty and thereby increase safety and operating margins. An example instrument loop uncertainty calculation for a pressure sensor application is presented to illustrate these improvements. This is a side-by-side comparison of the instrument loop uncertainty for both an analog and a digital sensor in the same pressure measurement application. Similarly, improved sensor reliability is illustrated with a sample calculation for determining the probability of failure on demand, an industry standard reliability measure. This looks at equivalent analog and digital temperature sensors to draw the comparison. The results confirm substantial reliability improvement with the digital sensor, due in large part to ability to continuously monitor the health of a digital sensor such that problems can be immediately identified and corrected. This greatly reduces the likelihood of a latent failure condition of the sensor at the time of a design basis event. Notwithstanding the benefits of digital sensors, there are certain qualification issues that are inherent with digital technology and these are described in the report. One major qualification impediment for digital sensor implementation is software common cause failure (SCCF).

  20. Modulation for terrestrial broadcasting of digital HDTV

    NASA Technical Reports Server (NTRS)

    Kohn, Elliott S.

    1991-01-01

    The digital modulation methods used by the DigiCipher, DSC-HDTV, ADTV, and ATVA-P digital high-definition television (HDTV) systems are discussed. Three of the systems use a quadrature amplitude modulation method, and the fourth uses a vestigial sideband modulation method. The channel equalization and spectrum sharing of the digital HDTV systems is discussed.

  1. Digital Libraries.

    ERIC Educational Resources Information Center

    Fox, Edward A.; Urs, Shalini R.

    2002-01-01

    Provides an overview of digital libraries research, practice, and literature. Highlights include new technologies; redefining roles; historical background; trends; creating digital content, including conversion; metadata; organizing digital resources; services; access; information retrieval; searching; natural language processing; visualization;…

  2. Cerebrovascular Safety of Sulfonylureas: The Role of KATP Channels in Neuroprotection and the Risk of Stroke in Patients With Type 2 Diabetes.

    PubMed

    Liu, Rui; Wang, Haitao; Xu, Baofeng; Chen, Wenliang; Turlova, Ekaterina; Dong, Nan; Sun, Christopher L F; Lu, Yangqingqin; Fu, Hanhui; Shi, Ranran; Barszczyk, Andrew; Yang, Dongzi; Jin, Tianru; Mannucci, Edoardo; Feng, Zhong-Ping; Sun, Hong-Shuo

    2016-09-01

    Sulfonylureas are ATP-sensitive potassium (KATP) channel blockers commonly used in the treatment of type 2 diabetes mellitus (T2DM). Activation of KATP channels plays a neuroprotective role in ischemia; thus, whether sulfonylureas affect the outcomes of stroke in patients with T2DM needs to be further studied. In our study, streptozotocin (STZ)-induced diabetic mice subjected to transient middle cerebral artery occlusion (MCAO) showed larger areas of brain damage and poorer behavioral outcomes. Blocking the KATP channel by tolbutamide increased neuronal injury induced by oxygen-glucose deprivation (OGD) in vitro and permanent MCAO (pMCAO) in vivo. Activating the KATP channel by diazoxide reduced the effects of both the OGD and pMCAO. Western blot analysis in STZ mouse brains indicated an early increase in protein levels of N-methyl-d-aspartate receptor 2B and postsynaptic density protein-95, followed by a decrease in phosphorylation of glycogen synthase kinase 3β. Our systematic meta-analysis indicated that patients with T2DM treated with sulfonylureas had a higher odds ratio for stroke morbidity than those who received comparator drugs. Taken together, these results suggest that sulfonylurea treatment in patients with T2DM may inhibit the neuroprotective effects of KATP channels and increase the risk of stroke. PMID:27207539

  3. From Realities to Values: A Strategy Framework for Digital Natives

    ERIC Educational Resources Information Center

    Blowers, Helene

    2010-01-01

    For many Digital Natives, text messaging or SMS is the communication channel of choice, but preferences in communication channels aren't the only distinguishing traits of Digital Natives. Attitudes and perceptions related to digital privacy, identity, creativity, piracy, and advocacy also help to set younger generations apart. So how does one take…

  4. Digital Spectrometers for Interplanetary Science Missions

    NASA Technical Reports Server (NTRS)

    Jarnot, Robert F.; Padmanabhan, Sharmila; Raffanti, Richard; Richards, Brian; Stek, Paul; Werthimer, Dan; Nikolic, Borivoje

    2010-01-01

    A fully digital polyphase spectrometer recently developed by the University of California Berkeley Wireless Research Center in conjunction with the Jet Propulsion Laboratory provides a low mass, power, and cost implementation of a spectrum channelizer for submillimeter spectrometers for future missions to the Inner and Outer Solar System. The digital polyphase filter bank spectrometer (PFB) offers broad bandwidth with high spectral resolution, minimal channel-to-channel overlap, and high out-of-band rejection.

  5. Hand Safety

    MedlinePlus

    ... en gatillo See More... Hand Anatomy Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening ... en gatillo See More... Hand Anatomy Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening ...

  6. Hand Safety

    MedlinePlus

    ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ...

  7. Digital Preservation.

    ERIC Educational Resources Information Center

    Yakel, Elizabeth

    2001-01-01

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

  8. RFI channels

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.

    1980-01-01

    A class of channel models is presented which exhibit varying burst error severity much like channels encountered in practice. An information-theoretic analysis of these channel models is made, and conclusions are drawn that may aid in the design of coded communication systems for realistic noisy channels.

  9. Real-time, digital pulse-shape discrimination in non-hazardous fast liquid scintillation detectors: Prospects for safety and security

    SciTech Connect

    Joyce, M. J.; Aspinall, M. D.; Cave, F. D.; Lavietes, A. D.

    2011-07-01

    Pulse-shape discrimination (PSD) in fast, organic scintillation detectors is a long-established technique used to separate neutrons and {gamma} rays in mixed radiation fields. In the analogue domain the method can achieve separation in real time, but all knowledge of the pulses themselves is lost thereby preventing the possibility of any post- or repeated analysis. Also, it is typically reliant on electronic systems that are largely obsolete and which require significant experience to set up. In the digital domain, PSD is often more flexible but significant post-processing has usually been necessary to obtain neutron/{gamma}-ray separation. Moreover, the scintillation media on which the technique relies usually have a low flash point and are thus deemed hazardous. This complicates the ease with which they are used in industrial applications. In this paper, results obtained with a new portable digital pulse-shape discrimination instrument are described. This instrument provides real-time, digital neutron/{gamma} separation whilst preserving the synchronization with the time-of-arrival for each event, and realizing throughputs of 3 x 10{sup 6} events per second. Furthermore, this system has been tested with a scintillation medium that is non-flammable and not hazardous. (authors)

  10. Mitsubishi experience on digital I and C and modernization

    SciTech Connect

    Shirasawa, H.; Samples, R. P.

    2012-07-01

    Digital systems are being applied to instrumentation and control (I and C) systems, including safety and non-safety systems, to accommodate obsolescence of existing analog devices or to obtain the benefits of digital I and C systems in new nuclear power plants as well as existing plants. This paper presents the Mitsubishi experience of digital I and C application and modernization. (authors)

  11. The Security Research of Digital Library Network

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Song, Ding-Li; Yan, Shu

    Digital library is a self-development needs for the modern library to meet the development requirements of the times, changing the way services and so on. digital library from the hardware, technology, management and other aspects to objective analysis of the factors of threats to digital library network security. We should face up the problems of digital library network security: digital library network hardware are "not hard", the technology of digital library is relatively lag, digital library management system is imperfect and other problems; the government should take active measures to ensure that the library funding, to enhance the level of network hardware, to upgrade LAN and prevention technology, to improve network control technology, network monitoring technology; to strengthen safety management concepts, to prefect the safety management system; and to improve the level of security management modernization for digital library.

  12. Practical quantum digital signature

    NASA Astrophysics Data System (ADS)

    Yin, Hua-Lei; Fu, Yao; Chen, Zeng-Bing

    2016-03-01

    Guaranteeing nonrepudiation, unforgeability as well as transferability of a signature is one of the most vital safeguards in today's e-commerce era. Based on fundamental laws of quantum physics, quantum digital signature (QDS) aims to provide information-theoretic security for this cryptographic task. However, up to date, the previously proposed QDS protocols are impractical due to various challenging problems and most importantly, the requirement of authenticated (secure) quantum channels between participants. Here, we present the first quantum digital signature protocol that removes the assumption of authenticated quantum channels while remaining secure against the collective attacks. Besides, our QDS protocol can be practically implemented over more than 100 km under current mature technology as used in quantum key distribution.

  13. Where Do Agricultural Producers Get Safety and Health Information?

    PubMed

    Chiu, Sophia; Cheyney, Marsha; Ramirez, Marizen; Gerr, Fred

    2015-01-01

    There is little empirical guidance regarding communication sources and channels used and trusted by agricultural producers. The goal of this study was to characterize frequency of use and levels of trust in agricultural safety and health information sources and channels accessed by agricultural producers. A sample of 195 agricultural producers was surveyed at county fairs in Iowa. Information was collected about the frequency of use and level of trust in 14 information sources and channels. Associations between age, gender, and education level and use and trust of each information source or channel were estimated using logistic regression. The sample consisted of 72% men with a mean age of 50.1 (SD = 15.6) years. Newspaper and magazine articles were the most commonly used agricultural safety and health information source or channel; 77% (n = 140) of respondents reporting using them at least monthly. Among those reporting monthly or more frequent use, 75% reported trusting mostly or completely, compared with 58% using and 49% trusting the Internet. High levels of use and trust of newspaper and magazine articles did not vary significantly by age, gender, or education level. Age in the highest tertile (57-83 years) was marginally associated with lower odds of using, as well as using and trusting, all the information sources and channels studied except for medical clinics (use only: odds ratio [OR], 3.51, 95% confidence interval [CI], 0.79-15.64; use and trust: OR, 5.90, 95% CI, 0.91-38.42). These findings suggest that traditional media may be more effective than digital media for delivering agricultural safety and health information to agricultural producers. Medical clinics may be an untapped venue for communicating with older agricultural producers. PMID:26237716

  14. Analysis of synchronous digital-modulation schemes for satellite communication

    NASA Technical Reports Server (NTRS)

    Takhar, G. S.; Gupta, S. C.

    1975-01-01

    The multipath communication channel for space communications is modeled as a multiplicative channel. This paper discusses the effects of multiplicative channel processes on the symbol error rate for quadrature modulation (QM) digital modulation schemes. An expression for the upper bound on the probability of error is derived and numerically evaluated. The results are compared with those obtained for additive channels.

  15. Digital Citizenship

    ERIC Educational Resources Information Center

    Isman, Aytekin; Canan Gungoren, Ozlem

    2014-01-01

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

  16. Crisis Communications in a Digital World

    ERIC Educational Resources Information Center

    Trump, Kenneth S.

    2015-01-01

    Kenneth Trump, a school safety expert who consults with districts on how to respond to school safety crises, explains how the new prevalence of threats of violence being delivered over digital and social media creates for administrators a "communication crisis" that unfolds alongside the real or perceived crisis of school safety being…

  17. Digital Natives or Digital Tribes?

    ERIC Educational Resources Information Center

    Watson, Ian Robert

    2013-01-01

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

  18. Digital TV processing system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Two digital video data compression systems directly applicable to the Space Shuttle TV Communication System were described: (1) For the uplink, a low rate monochrome data compressor is used. The compression is achieved by using a motion detection technique in the Hadamard domain. To transform the variable source rate into a fixed rate, an adaptive rate buffer is provided. (2) For the downlink, a color data compressor is considered. The compression is achieved first by intra-color transformation of the original signal vector, into a vector which has lower information entropy. Then two-dimensional data compression techniques are applied to the Hadamard transformed components of this last vector. Mathematical models and data reliability analyses were also provided for the above video data compression techniques transmitted over a channel encoded Gaussian channel. It was shown that substantial gains can be achieved by the combination of video source and channel coding.

  19. TRP Channels

    PubMed Central

    Venkatachalam, Kartik; Montell, Craig

    2011-01-01

    The TRP (Transient Receptor Potential) superfamily of cation channels is remarkable in that it displays greater diversity in activation mechanisms and selectivities than any other group of ion channels. The domain organizations of some TRP proteins are also unusual, as they consist of linked channel and enzyme domains. A unifying theme in this group is that TRP proteins play critical roles in sensory physiology, which include contributions to vision, taste, olfaction, hearing, touch, and thermo- and osmosensation. In addition, TRP channels enable individual cells to sense changes in their local environment. Many TRP channels are activated by a variety of different stimuli and function as signal integrators. The TRP superfamily is divided into seven subfamilies: the five group 1 TRPs (TRPC, TRPV, TRPM, TRPN, and TRPA) and two group 2 subfamilies (TRPP and TRPML). TRP channels are important for human health as mutations in at least four TRP channels underlie disease. PMID:17579562

  20. CDC Vital Signs: Trucker Safety

    MedlinePlus

    ... Clips Trucker Safety Using a seat belt matters Language: English Español (Spanish) Recommend on Facebook Tweet Share ... Digital Press Kit Read the MMWR Science Clips Language: English Español (Spanish) File Formats Help: How do ...

  1. Efficacy and safety of memantine, an NMDA-type open-channel blocker, for reduction of retinal injury associated with experimental glaucoma in rat and monkey.

    PubMed

    Hare, W; WoldeMussie, E; Lai, R; Ton, H; Ruiz, G; Feldmann, B; Wijono, M; Chun, T; Wheeler, L

    2001-05-01

    Glutamatergic excitotoxicity has been implicated as a mechanism for injury in a variety of central nervous system pathologies, including glaucoma. Memantine, an NMDA-type glutamatergic open-channel blocker, has pharmacologic properties that make its efficacy greater under excitotoxic conditions, but lesser under normal conditions. Daily oral dosing for approximately 15 months with 4.0 mg/kg memantine in monkeys yielded plasma concentrations similar to those found in patients who received memantine treatment for Parkinson's disease. This same dose of memantine was not associated with any evidence of an effect on the normal function of the retina and central visual pathways, as indicated by measures of the electroretinogram (ERG) and visually-evoked cortical potential (VECP). Amplitude of the VECP response was reduced in eyes with experimentally induced glaucoma. When compared to vehicle-treated control animals, memantine-treated glaucoma eyes suffered significantly less reduction of VECP amplitude. Preliminary results in a rat model for experimental glaucoma also show that, when compared to control animals, systemic treatment with memantine (10 mg/kg/day) was associated with a significant reduction in glaucoma-induced loss of retinal ganglion cells. PMID:11377450

  2. Nuclear safety

    NASA Technical Reports Server (NTRS)

    Buden, D.

    1991-01-01

    Topics dealing with nuclear safety are addressed which include the following: general safety requirements; safety design requirements; terrestrial safety; SP-100 Flight System key safety requirements; potential mission accidents and hazards; key safety features; ground operations; launch operations; flight operations; disposal; safety concerns; licensing; the nuclear engine for rocket vehicle application (NERVA) design philosophy; the NERVA flight safety program; and the NERVA safety plan.

  3. Digital audio and video broadcasting by satellite

    NASA Astrophysics Data System (ADS)

    Yoshino, Takehiko

    In parallel with the progress of the practical use of satellite broadcasting and Hi-Vision or high-definition television technologies, research activities are also in progress to replace the conventional analog broadcasting services with a digital version. What we call 'digitalization' is not a mere technical matter but an important subject which will help promote multichannel or multimedia applications and, accordingly, can change the old concept of mass media, such as television or radio. NHK Science and Technical Research Laboratories has promoted studies of digital bandwidth compression, transmission, and application techniques. The following topics are covered: the trend of digital broadcasting; features of Integrated Services Digital Broadcasting (ISDB); compression encoding and transmission; transmission bit rate in 12 GHz band; number of digital TV transmission channels; multichannel pulse code modulation (PCM) audio broadcasting system via communication satellite; digital Hi-Vision broadcasting; and development of digital audio broadcasting (DAB) for mobile reception in Japan.

  4. Web-based multi-channel analyzer

    DOEpatents

    Gritzo, Russ E.

    2003-12-23

    The present invention provides an improved multi-channel analyzer designed to conveniently gather, process, and distribute spectrographic pulse data. The multi-channel analyzer may operate on a computer system having memory, a processor, and the capability to connect to a network and to receive digitized spectrographic pulses. The multi-channel analyzer may have a software module integrated with a general-purpose operating system that may receive digitized spectrographic pulses for at least 10,000 pulses per second. The multi-channel analyzer may further have a user-level software module that may receive user-specified controls dictating the operation of the multi-channel analyzer, making the multi-channel analyzer customizable by the end-user. The user-level software may further categorize and conveniently distribute spectrographic pulse data employing non-proprietary, standard communication protocols and formats.

  5. Low power, CMOS digital autocorrelator spectrometer for spaceborne applications

    NASA Technical Reports Server (NTRS)

    Chandra, Kumar; Wilson, William J.

    1992-01-01

    A 128-channel digital autocorrelator spectrometer using four 32 channel low power CMOS correlator chips was built and tested. The CMOS correlator chip uses a 2-bit multiplication algorithm and a full-custom CMOS VLSI design to achieve low DC power consumption. The digital autocorrelator spectrometer has a 20 MHz band width, and the total DC power requirement is 6 Watts.

  6. Digital metamaterials

    NASA Astrophysics Data System (ADS)

    Della Giovampaola, Cristian; Engheta, Nader

    2014-12-01

    Balancing complexity and simplicity has played an important role in the development of many fields in science and engineering. One of the well-known and powerful examples of such balance can be found in Boolean algebra and its impact on the birth of digital electronics and the digital information age. The simplicity of using only two numbers, ‘0’ and ‘1’, in a binary system for describing an arbitrary quantity made the fields of digital electronics and digital signal processing powerful and ubiquitous. Here, inspired by the binary concept, we propose to develop the notion of digital metamaterials. Specifically, we investigate how one can synthesize an electromagnetic metamaterial with a desired permittivity, using as building blocks only two elemental materials, which we call ‘metamaterial bits’, with two distinct permittivity functions. We demonstrate, analytically and numerically, how proper spatial mixtures of such metamaterial bits lead to elemental ‘metamaterial bytes’ with effective material parameters that are different from the parameters of the metamaterial bits. We then apply this methodology to several design examples of optical elements, such as digital convex lenses, flat graded-index digital lenses, digital constructs for epsilon-near-zero (ENZ) supercoupling and digital hyperlenses, thus highlighting the power and simplicity of the methodology.

  7. Digital metamaterials.

    PubMed

    Della Giovampaola, Cristian; Engheta, Nader

    2014-12-01

    Balancing complexity and simplicity has played an important role in the development of many fields in science and engineering. One of the well-known and powerful examples of such balance can be found in Boolean algebra and its impact on the birth of digital electronics and the digital information age. The simplicity of using only two numbers, '0' and '1', in a binary system for describing an arbitrary quantity made the fields of digital electronics and digital signal processing powerful and ubiquitous. Here, inspired by the binary concept, we propose to develop the notion of digital metamaterials. Specifically, we investigate how one can synthesize an electromagnetic metamaterial with a desired permittivity, using as building blocks only two elemental materials, which we call 'metamaterial bits', with two distinct permittivity functions. We demonstrate, analytically and numerically, how proper spatial mixtures of such metamaterial bits lead to elemental 'metamaterial bytes' with effective material parameters that are different from the parameters of the metamaterial bits. We then apply this methodology to several design examples of optical elements, such as digital convex lenses, flat graded-index digital lenses, digital constructs for epsilon-near-zero (ENZ) supercoupling and digital hyperlenses, thus highlighting the power and simplicity of the methodology. PMID:25218061

  8. Digital Data Transmission Via CATV.

    ERIC Educational Resources Information Center

    Stifle, Jack; And Others

    A low cost communications network has been designed for use in the PLATO IV computer-assisted instruction system. Over 1,000 remote computer graphic terminals each requiring a 1200 bps channel are to be connected to one centrally located computer. Digital data are distributed to these terminals using standard commercial cable television (CATV)…

  9. BROADBAND DIGITAL GEOPHYSICAL TELEMETRY SYSTEM.

    USGS Publications Warehouse

    Seeley, Robert L.; Daniels, Jeffrey J.

    1984-01-01

    A system has been developed to simultaneously sample and transmit digital data from five remote geophysical data receiver stations to a control station that processes, displays, and stores the data. A microprocessor in each remote station receives commands from the control station over a single telemetry channel.

  10. Digital Receiver Phase Meter

    NASA Technical Reports Server (NTRS)

    Marcin, Martin; Abramovici, Alexander

    2008-01-01

    The software of a commercially available digital radio receiver has been modified to make the receiver function as a two-channel low-noise phase meter. This phase meter is a prototype in the continuing development of a phase meter for a system in which radiofrequency (RF) signals in the two channels would be outputs of a spaceborne heterodyne laser interferometer for detecting gravitational waves. The frequencies of the signals could include a common Doppler-shift component of as much as 15 MHz. The phase meter is required to measure the relative phases of the signals in the two channels at a sampling rate of 10 Hz at a root power spectral density <5 microcycle/(Hz)1/2 and to be capable of determining the power spectral density of the phase difference over the frequency range from 1 mHz to 1 Hz. Such a phase meter could also be used on Earth to perform similar measurements in laser metrology of moving bodies. To illustrate part of the principle of operation of the phase meter, the figure includes a simplified block diagram of a basic singlechannel digital receiver. The input RF signal is first fed to the input terminal of an analog-to-digital converter (ADC). To prevent aliasing errors in the ADC, the sampling rate must be at least twice the input signal frequency. The sampling rate of the ADC is governed by a sampling clock, which also drives a digital local oscillator (DLO), which is a direct digital frequency synthesizer. The DLO produces samples of sine and cosine signals at a programmed tuning frequency. The sine and cosine samples are mixed with (that is, multiplied by) the samples from the ADC, then low-pass filtered to obtain in-phase (I) and quadrature (Q) signal components. A digital signal processor (DSP) computes the ratio between the Q and I components, computes the phase of the RF signal (relative to that of the DLO signal) as the arctangent of this ratio, and then averages successive such phase values over a time interval specified by the user.

  11. Technical basis for environmental qualification of computer-based safety systems in nuclear power plants

    SciTech Connect

    Korsah, K.; Wood, R.T.; Tanaka, T.J.; Antonescu, C.E.

    1997-10-01

    This paper summarizes the results of research sponsored by the US Nuclear Regulatory Commission (NRC) to provide the technical basis for environmental qualification of computer-based safety equipment in nuclear power plants. This research was conducted by the Oak Ridge National Laboratory (ORNL) and Sandia National Laboratories (SNL). ORNL investigated potential failure modes and vulnerabilities of microprocessor-based technologies to environmental stressors, including electromagnetic/radio-frequency interference, temperature, humidity, and smoke exposure. An experimental digital safety channel (EDSC) was constructed for the tests. SNL performed smoke exposure tests on digital components and circuit boards to determine failure mechanisms and the effect of different packaging techniques on smoke susceptibility. These studies are expected to provide recommendations for environmental qualification of digital safety systems by addressing the following: (1) adequacy of the present preferred test methods for qualification of digital I and C systems; (2) preferred standards; (3) recommended stressors to be included in the qualification process during type testing; (4) resolution of need for accelerated aging in qualification testing for equipment that is to be located in mild environments; and (5) determination of an appropriate approach to address smoke in a qualification program.

  12. Digital Electronics for Nuclear Physics Experiments

    NASA Astrophysics Data System (ADS)

    Skulski, Wojtek; Hunter, David; Druszkiewicz, Eryk; Khaitan, Dev Ashish; Yin, Jun; Wolfs, Frank; SkuTek Instrumentation Team; Department of Physics; Astronomy, University of Rochester Team

    2015-10-01

    Future detectors in nuclear physics will use signal sampling as one of primary techniques of data acquisition. Using the digitized waveforms, the electronics can select events based on pulse shape, total energy, multiplicity, and the hit pattern. The DAQ for the LZ Dark Matter detector, now under development in Rochester, is a good example of the power of digital signal processing. This system, designed around 32-channel, FPGA-based, digital signal processors collects data from more than one thousand channels. The solutions developed for this DAQ can be applied to nuclear physics experiments. Supported by the Department of Energy Office of Science under Grant DE-SC0009543.

  13. Digital Opportunity

    ERIC Educational Resources Information Center

    Azzam, Amy M.

    2006-01-01

    This article details the content of a recently released report from the Children's Partnership titled "Measuring Digital Opportunity for America's Children: Where We Stand and Where We Go From Here". On the basis of 40 indicators, the report's Digital Opportunity Measuring Stick showed how U.S. children and young adults use information and…

  14. Digital TMI

    NASA Technical Reports Server (NTRS)

    Rios, Joseph

    2012-01-01

    Presenting the current status of the Digital TMI project to visiting members of the FAA Command Center. Digital TMI is an effort to store national-level traffic management initiatives in a standards-compliant manner. Work is funded by the FAA.

  15. Digital Discrimination

    ERIC Educational Resources Information Center

    Blansett, Jim

    2008-01-01

    In recent years, the Internet has become a digital commons of commerce and education. However, accessibility standards have often been overlooked online, and the digital equivalents to curb-cuts and other physical accommodations have only rarely been implemented to serve those with print disabilities. (A print disability can be a learning…

  16. Digital Roundup

    ERIC Educational Resources Information Center

    Horn, Michael B.

    2013-01-01

    State policy is crucial to the spread of digital-learning opportunities at the elementary and secondary level. A review of recent legislative action reveals policies that are constantly in flux and differ quite markedly from one state to another. Some have hoped for model digital-learning legislation that could handle all the various issues…

  17. Why Digitize?

    ERIC Educational Resources Information Center

    Smith, Abby

    This paper is a response to discussions of digitization at meetings of the National Humanities Alliance (NHA). NHA asked the Council on Library and Information Resources (CLIR) to evaluate the experiences of cultural institutions with digitization projects to date and to summarize what has been learned about the advantages and disadvantages of…

  18. Lessons learned in digital upgrade projects digital control system implementation at US nuclear power stations

    SciTech Connect

    Kelley, S.; Bolian, T. W.

    2006-07-01

    AREVA NP has gained significant experience during the past five years in digital upgrades at operating nuclear power stations in the US. Plants are seeking modernization with digital technology to address obsolescence, spare parts availability, vendor support, increasing age-related failures and diminished reliability. New systems offer improved reliability and functionality, and decreased maintenance requirements. Significant lessons learned have been identified relating to the areas of licensing, equipment qualification, software quality assurance and other topics specific to digital controls. Digital control systems have been installed in non safety-related control applications at many utilities within the last 15 years. There have also been a few replacements of small safety-related systems with digital technology. Digital control systems are proving to be reliable, accurate, and easy to maintain. Digital technology is gaining acceptance and momentum with both utilities and regulatory agencies based upon the successes of these installations. Also, new plants are being designed with integrated digital control systems. To support plant life extension and address obsolescence of critical components, utilities are beginning to install digital technology for primary safety-system replacement. AREVA NP analyzed operating experience and lessons learned from its own digital upgrade projects as well as industry-wide experience to identify key issues that should be considered when implementing digital controls in nuclear power stations.

  19. Programmable Digital Controller

    NASA Technical Reports Server (NTRS)

    Wassick, Gregory J.

    2012-01-01

    An existing three-channel analog servo loop controller has been redesigned for piezoelectric-transducer-based (PZT-based) etalon control applications to a digital servo loop controller. This change offers several improvements over the previous analog controller, including software control over proportional-integral-derivative (PID) parameters, inclusion of other data of interest such as temperature and pressure in the control laws, improved ability to compensate for PZT hysteresis and mechanical mount fluctuations, ability to provide pre-programmed scanning and stepping routines, improved user interface, expanded data acquisition, and reduced size, weight, and power.

  20. Channel catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter provides a comprehensive overview of channel catfish aquaculture. Sections include fish biology; commercial culture; culture facilities; production practices; water quality management; nutrition, feeding and feed formulation; infectious diseases; harvesting and processing; and the...

  1. Automatic color map digitization by spectral classification

    NASA Technical Reports Server (NTRS)

    Chu, N. Y.; Anuta, P. E.

    1979-01-01

    A method of converting polygon map information into a digital form which does not require manual tracing of polygon edges is discussed. The maps must be in color-coded format with a unique color for each category in the map. Color scanning using a microdensitometer is employed and a three-channel color separation digital data set is generated. The digital data are then classified by using a Gaussian maximum likelihood classifier, and the resulting digitized map is evaluated. Very good agreement is observed between the classified and original map.

  2. Digital clubbing

    PubMed Central

    Sarkar, Malay; Mahesh, D. M.; Madabhavi, Irappa

    2012-01-01

    Digital clubbing is an ancient and important clinical signs in medicine. Although clubbed fingers are mostly asymptomatic, it often predicts the presence of some dreaded underlying diseases. Its exact pathogenesis is not known, but platelet-derived growth factor and vascular endothelial growth factor are recently incriminated in its causation. The association of digital clubbing with various disease processes and its clinical implications are discussed in this review. PMID:23243350

  3. Digital Epidemiology

    PubMed Central

    Salathé, Marcel; Bengtsson, Linus; Bodnar, Todd J.; Brewer, Devon D.; Brownstein, John S.; Buckee, Caroline; Campbell, Ellsworth M.; Cattuto, Ciro; Khandelwal, Shashank; Mabry, Patricia L.; Vespignani, Alessandro

    2012-01-01

    Mobile, social, real-time: the ongoing revolution in the way people communicate has given rise to a new kind of epidemiology. Digital data sources, when harnessed appropriately, can provide local and timely information about disease and health dynamics in populations around the world. The rapid, unprecedented increase in the availability of relevant data from various digital sources creates considerable technical and computational challenges. PMID:22844241

  4. Digital photography

    PubMed Central

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

    2006-01-01

    Objective The emergence of a new generation of “point‐and‐shoot” digital cameras offers doctors a compact, portable and user‐friendly solution to the recording of highly detailed digital photographs and video images. This work highlights the use of such technology, and provides information for those who wish to record, store and display their own medical images. Methods Over a 3‐month period, a digital camera was carried by a doctor in a busy, adult emergency department and used to record a range of clinical images that were subsequently transferred to a computer database. Results In total, 493 digital images were recorded, of which 428 were photographs and 65 were video clips. These were successfully used for teaching purposes, publications and patient records. Conclusions This study highlights the importance of informed consent, the selection of a suitable package of digital technology and the role of basic photographic technique in developing a successful digital database in a busy clinical environment. PMID:17068281

  5. Digital radiography.

    PubMed

    Mattoon, J S

    2006-01-01

    Digital radiography has been used in human medical imaging since the 1980s with recent and rapid acceptance into the veterinary profession. Using advanced image capture and computer technology, radiographic images are viewed on a computer monitor. This is advantageous because radiographic images can be adjusted using dedicated computer software to maximize diagnostic image quality. Digital images can be accessed at computer workstations throughout the hospital, instantly retrieved from computer archives, and transmitted via the internet for consultation or case referral. Digital radiographic data can also be incorporated into a hospital information system, making record keeping an entirely paperless process. Digital image acquisition is faster when compared to conventional screen-film radiography, improving workflow and patient throughput. Digital radiography greatly reduces the need for 'retake' radiographs because of wide latitude in exposure factors. Also eliminated are costs associated with radiographic film and x-ray film development. Computed radiography, charged coupled devices, and flat panel detectors are types of digital radiography systems currently available. PMID:16971994

  6. Digital Collections, Digital Libraries & the Digitization of Cultural Heritage Information.

    ERIC Educational Resources Information Center

    Lynch, Clifford

    2002-01-01

    Discusses digital collections and digital libraries. Topics include broadband availability; digital rights protection; content, both non-profit and commercial; digitization of cultural content; sustainability; metadata harvesting protocol; infrastructure; authorship; linking multiple resources; data mining; digitization of reference works;…

  7. Reactor safety method

    DOEpatents

    Vachon, Lawrence J.

    1980-03-11

    This invention relates to safety means for preventing a gas cooled nuclear reactor from attaining criticality prior to start up in the event the reactor core is immersed in hydrogenous liquid. This is accomplished by coating the inside surface of the reactor coolant channels with a neutral absorbing material that will vaporize at the reactor's operating temperature.

  8. A Channelization-Based DOA Estimation Method for Wideband Signals

    PubMed Central

    Guo, Rui; Zhang, Yue; Lin, Qianqiang; Chen, Zengping

    2016-01-01

    In this paper, we propose a novel direction of arrival (DOA) estimation method for wideband signals with sensor arrays. The proposed method splits the wideband array output into multiple frequency sub-channels and estimates the signal parameters using a digital channelization receiver. Based on the output sub-channels, a channelization-based incoherent signal subspace method (Channelization-ISM) and a channelization-based test of orthogonality of projected subspaces method (Channelization-TOPS) are proposed. Channelization-ISM applies narrowband signal subspace methods on each sub-channel independently. Then the arithmetic mean or geometric mean of the estimated DOAs from each sub-channel gives the final result. Channelization-TOPS measures the orthogonality between the signal and the noise subspaces of the output sub-channels to estimate DOAs. The proposed channelization-based method isolates signals in different bandwidths reasonably and improves the output SNR. It outperforms the conventional ISM and TOPS methods on estimation accuracy and dynamic range, especially in real environments. Besides, the parallel processing architecture makes it easy to implement on hardware. A wideband digital array radar (DAR) using direct wideband radio frequency (RF) digitization is presented. Experiments carried out in a microwave anechoic chamber with the wideband DAR are presented to demonstrate the performance. The results verify the effectiveness of the proposed method. PMID:27384566

  9. A Channelization-Based DOA Estimation Method for Wideband Signals.

    PubMed

    Guo, Rui; Zhang, Yue; Lin, Qianqiang; Chen, Zengping

    2016-01-01

    In this paper, we propose a novel direction of arrival (DOA) estimation method for wideband signals with sensor arrays. The proposed method splits the wideband array output into multiple frequency sub-channels and estimates the signal parameters using a digital channelization receiver. Based on the output sub-channels, a channelization-based incoherent signal subspace method (Channelization-ISM) and a channelization-based test of orthogonality of projected subspaces method (Channelization-TOPS) are proposed. Channelization-ISM applies narrowband signal subspace methods on each sub-channel independently. Then the arithmetic mean or geometric mean of the estimated DOAs from each sub-channel gives the final result. Channelization-TOPS measures the orthogonality between the signal and the noise subspaces of the output sub-channels to estimate DOAs. The proposed channelization-based method isolates signals in different bandwidths reasonably and improves the output SNR. It outperforms the conventional ISM and TOPS methods on estimation accuracy and dynamic range, especially in real environments. Besides, the parallel processing architecture makes it easy to implement on hardware. A wideband digital array radar (DAR) using direct wideband radio frequency (RF) digitization is presented. Experiments carried out in a microwave anechoic chamber with the wideband DAR are presented to demonstrate the performance. The results verify the effectiveness of the proposed method. PMID:27384566

  10. Vaccine Safety Resources for Nurses

    PubMed Central

    Shimabukuro, Tom T.; Hibbs, Beth F.; Moro, Pedro L.; Broder, Karen R.; Vellozzi, Claudia

    2015-01-01

    Overview Nurses are on the front lines of health care delivery, and many of them routinely administer immunizations. The authors describe the Centers for Disease Control and Prevention’s (CDC) vaccine safety monitoring systems, explaining how nurses can access inquiry channels and other immunization information resources. Examples of recent vaccine safety inquiries are also provided. PMID:26222474

  11. Digital television system design study

    NASA Technical Reports Server (NTRS)

    Huth, G. K.

    1976-01-01

    The use of digital techniques for transmission of pictorial data is discussed for multi-frame images (television). Video signals are processed in a manner which includes quantization and coding such that they are separable from the noise introduced into the channel. The performance of digital television systems is determined by the nature of the processing techniques (i.e., whether the video signal itself or, instead, something related to the video signal is quantized and coded) and to the quantization and coding schemes employed.

  12. 47 CFR 101.1405 - Channeling plan.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Channeling plan. 101.1405 Section 101.1405 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... Channeling plan. Each license shall have one spectrum block of 500 megahertz per geographic area that can...

  13. 47 CFR 101.1405 - Channeling plan.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Channeling plan. 101.1405 Section 101.1405 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... Channeling plan. Each license shall have one spectrum block of 500 megahertz per geographic area that can...

  14. 47 CFR 101.1405 - Channeling plan.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Channeling plan. 101.1405 Section 101.1405 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... Channeling plan. Each license shall have one spectrum block of 500 megahertz per geographic area that can...

  15. 47 CFR 101.1405 - Channeling plan.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Channeling plan. 101.1405 Section 101.1405 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... Channeling plan. Each license shall have one spectrum block of 500 megahertz per geographic area that can...

  16. 47 CFR 101.1405 - Channeling plan.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Channeling plan. 101.1405 Section 101.1405 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... Channeling plan. Each license shall have one spectrum block of 500 megahertz per geographic area that can...

  17. TRP channels.

    PubMed

    Benemei, Silvia; Patacchini, Riccardo; Trevisani, Marcello; Geppetti, Pierangelo

    2015-06-01

    Evidence is accumulating on the role of transient receptor potential (TRP) channels, namely TRPV1, TRPA1, TRPV4 and TRPM8, expressed by C- and Aδ-fibres primary sensory neurons, in cough mechanism. Selective stimuli for these channels have been proven to provoke and, more rarely, to inhibit cough. More importantly, cough threshold to TRP agonists is increased by proinflammatory conditions, known to favour cough. Off-target effects of various drugs, such as tiotropium or desflurane, seem to produce their protective or detrimental actions on airway irritation and cough via TRPV1 and TRPA1, respectively. Thus, TRPs appear to encode the process that initiates or potentiates cough, activated by exogenous irritants and endogenous proinflammatory mediators. More research on TRP channels may result in innovative cough medicines. PMID:25725213

  18. Crossing the Digital Divide

    SciTech Connect

    Ken Thomas

    2011-11-01

    Nuclear utilities continue to upgrade aging instrumentation and control (I&C) systems with modern digital-based systems to address reliability and obsolescence concerns. In addition, the industry has demonstrated that these systems can be successfully developed and deployed even for highly safety-significant applications, such as reactor protection. However, three factors have retarded wide-scale implementation of digital technology for plant modernization and business innovation: *Large-scale digital upgrades entail considerable risk; *The upgrades are very costly and have not led to bottom-line business improvement, financial or otherwise; *Cyber Security concerns discourage wide-scale digital integration. A new national research program is under way that has been designed to address these industry concerns about expanding the use of digital technology. The Idaho National Laboratory (INL) has lead responsibility for the Advanced Instrumentation, Information, and Control Systems Technologies research pathway within the Light Water Reactor Sustainability (LWRS) Program. The LWRS Program is a research and development (R&D) program sponsored by the U.S. Department of Energy (DOE) and performed in close collaboration with industry R&D and improvement programs (as defined in INL’s FY2009–2013 Light Water Reactor Sustainability Research and Development Program Plan, INL/MIS08-14918). Its purpose is to provide the technical foundations for licensing and managing the long-term, safe, and economical operation of existing nuclear power plants. The DOE’s program focus is on longer-term and higher-risk/reward research that contributes to the national policy objectives of energy security and environmental security. The specific concern addressed by this program is that large-scale I&C obsolescence could become a life-limiting issue for the current nuclear operating fleet.

  19. Digital caliper

    USGS Publications Warehouse

    Cable, Louella E.

    1967-01-01

    The large number of measurements needed to describe fully the characteristics of biological specimens and other objects has always been tedious and time consuming. The work can be done much more rapidly and with greater accuracy with a digital caliper recently developed by us. The digital caliper is a new electronic instrument built to measure objects precisely throughout the range of 0.1 mm to 1.0 m. Calipers of several different discrete sizes make it possible to select the most convenient unit for the particular range of length and degree of accuracy desired.

  20. Digital Radiography

    NASA Technical Reports Server (NTRS)

    1986-01-01

    System One, a digital radiography system, incorporates a reusable image medium (RIM) which retains an image. No film is needed; the RIM is read with a laser scanner, and the information is used to produce a digital image on an image processor. The image is stored on an optical disc. System allows the radiologist to "dial away" unwanted images to compare views on three screens. It is compatible with existing equipment and cost efficient. It was commercialized by a Stanford researcher from energy selective technology developed under a NASA grant.

  1. Management Matters. Safety in a Digital Environment

    ERIC Educational Resources Information Center

    Pappas, Marjorie L.

    2004-01-01

    Library media specialists find themselves in a challenging position today. They know that the Internet opens up information access in exciting ways, so they do not want to scare people; but they do need to inform them about practices for using the Internet that will keep young people safe. They have a responsibility to inform other educators,…

  2. Modem for the land mobile satellite channel

    NASA Technical Reports Server (NTRS)

    Henely, Steven J.

    1988-01-01

    This paper describes a modem which has been developed and implemented using a digital signal processor (DSP) for a land mobile satellite demonstration system. The requirements of this digital modem were determined by the characteristics of the land mobile satellite channel. This paper discusses the algorithms which implement the differentiated phase shift keying (DPSK) demodulator. An algorithm is included which estimates symbol timing independent of carrier phase without the use of a square-law nonlinearity.

  3. Analysis of digital matched filtering schemes for digital receiver applications using simulation methods

    NASA Technical Reports Server (NTRS)

    Gevargiz, J. M.; Holmes, J. K.

    1991-01-01

    The next generation of digital receivers for NASA's Deep Space Network is composed of in-phase and quadrature-phase channels. The authors have modeled and simulated a quadrature-phase baseband channel that includes a low-pass filter and a digital matched filter. The simulation is used to study the performance of the three schemes of digital matched filtering that use digital weighted integrate-and-dump filters. Using three methods for calculating the near-optimum matched filter weight coefficients, the simulation results are analyzed for the NRZ and Manchester data formats. The performances of the digital matched filters are studied in the presence of a timing error between the demodulated symbols and the integrate-and-dump filters.

  4. Modems for emerging digital cellular-mobile radio system

    NASA Technical Reports Server (NTRS)

    Feher, Kamilo

    1991-01-01

    Digital modem techniques for emerging digital cellular telecommunications-mobile radio system applications are described and analyzed. In particular, theoretical performance, experimental results, principles of operation, and various architectures of pi/4-QPSK (pi/4-shifted coherent or differential QPSK) modems for second-generation US digital cellular radio system applications are presented. The spectral/power efficiency and performance of the pi/4-QPSK modems (American and Japanese digital cellular emerging standards) are studied and briefly compared to GMSK (Gaussian minimum-shift keying) modems (proposed for European DECT and GSM cellular standards). Improved filtering strategies and digital pilot-aided (digital channel sounding) techniques are also considered for pi/4-QPSK and other digital modems. These techniques could significantly improve the performance of digital cellular and other digital land mobile and satellite mobile radio systems. More spectrally efficient modem trends for future cellular/mobile (land mobile) and satellite communication systems applications are also highlighted.

  5. Digital Tidbits

    ERIC Educational Resources Information Center

    Kumaran, Maha; Geary, Joe

    2011-01-01

    Technology has transformed libraries. There are digital libraries, electronic collections, online databases and catalogs, ebooks, downloadable books, and much more. With free technology such as social websites, newspaper collections, downloadable online calendars, clocks and sticky notes, online scheduling, online document sharing, and online…

  6. Digital books.

    PubMed

    Wink, Diane M

    2011-01-01

    In this bimonthly series, the author examines how nurse educators can use the Internet and Web-based computer technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes digital books. PMID:22024672

  7. Digital Badges

    ERIC Educational Resources Information Center

    Frederiksen, Linda

    2013-01-01

    Unlike so much of the current vocabulary in education and technology that seems to stir more confusion than clarity, most public service librarians may already have a general idea about digital badges. As visual representations of individual accomplishments, competencies or skills that are awarded by groups, institutions, or organizations, they…

  8. The channels of Mars

    NASA Technical Reports Server (NTRS)

    Baker, Victor R.

    1988-01-01

    The geomorphology of Mars is discussed, focusing on the Martian channels. The great flood channels of Mars, the processes of channel erosion, and dendritic channel networks, are examined. The topography of the Channeled Scabland region of the northwestern U.S. is described and compared to the Martian channels. The importance of water in the evolution of the channel systems is considered.

  9. Starburst Channels

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1

    Translucent carbon dioxide ice covers the polar regions of Mars seasonally. It is warmed and sublimates (evaporates) from below, and escaping gas carves a numerous channel morphologies.

    In this example (figure 1) the channels form a 'starburst' pattern, radiating out into feathery extensions. The center of the pattern is being buried with dust and new darker dust fans ring the outer edges. This may be an example of an expanding morphology, where new channels are formed as the older ones fill and are no longer efficiently channeling the subliming gas out.

    Observation Geometry Image PSP_003443_0980 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 21-Apr-2007. The complete image is centered at -81.8 degrees latitude, 76.2 degrees East longitude. The range to the target site was 247.1 km (154.4 miles). At this distance the image scale is 24.7 cm/pixel (with 1 x 1 binning) so objects 74 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel. The image was taken at a local Mars time of 04:52 PM and the scene is illuminated from the west with a solar incidence angle of 71 degrees, thus the sun was about 19 degrees above the horizon. At a solar longitude of 223.4 degrees, the season on Mars is Northern Autumn.

  10. Direct qualification of digital components

    SciTech Connect

    Lawrence, J. D., LLNL

    1998-07-08

    Existing methods for qualifying digital system software for use in safety critical systems are expensive and are based on inferences that are of doubtful validity. This report on work-in-progress describes a new approach to qualifying a class of small safety systems that can meet a number of design restrictions, where the restrictions are carefully crafted to permit safety qualification to be determined by means of static analysis of the software combined with a limited amount of testing. This approach differs from attempts to qualify unrestricted programs in the general case. Work that has been accomplished towards this goal is discussed in summary terms. The technique relies on transforming a program into a form of directed graph known as a flowgraph. Existing testing theory is used, sometimes with minor modifications, to derive a set of design restrictions that permit reasoning about safety properties of the program, based on analysis and limited testing. Future work required to complete the research is outlined.

  11. Summertime Safety

    MedlinePlus

    ... Violence & Safety Life Stages & Populations Travelers' Health Workplace Safety & Health Features Media Sign up for Features Get Email Updates ... Submit What's this? Submit Button Past Emails CDC Features Summertime Safety Recommend on Facebook Tweet Share Compartir The feature ...

  12. Drug Safety

    MedlinePlus

    ... over-the-counter drug. The FDA evaluates the safety of a drug by looking at Side effects ... clinical trials The FDA also monitors a drug's safety after approval. For you, drug safety means buying ...

  13. Safety Education.

    ERIC Educational Resources Information Center

    Daniels, James H.; And Others

    1980-01-01

    Five articles in this issue focus on safety education in agricultural laboratories. Topics discussed include teacher liability; elements of a safety instruction program; state and federal safety standards; ground fault current protection; and eye protection requirements and equipment. (SK)

  14. Digital psychiatry.

    PubMed

    Tang, S; Helmeste, D

    2000-02-01

    The American managed care movement has been viewed as a big experiment and is being watched closely by the rest of the world. In the meanwhile, computer-based information technology (IT) is changing the practice of medicine, much more rapidly than managed care. A New World of digitized knowledge and information has been created. Although literature on IT in psychiatry is largely absent in peer-reviewed psychiatric journals, IT is finding its way into all aspects of medicine, particularly psychiatry. Telepsychiatry programs are becoming very popular. At the same time, medical information sites are flourishing and evolving into a new health-care industry. Patient-physician information asymmetry is decreasing as patients are gaining easy access to medical information hitherto only available to professionals. Thus, psychiatry is facing another paradigm shift, at a time when most attention has been focused on managed care. In this new digital world, knowledge and information are no longer the sole property of professionals. Value will migrate from traditional in-person office-based therapy to digital clinical products, from in-person library search and classroom didactic instruction to interactive on-line searches and distance learning. In this time of value migration, psychiatrists have to determine what their 'distinctive competence' is and where best to add value in the health-care delivery value chain. The authors assess the impact of IT on clinical psychiatry and review how clinical practice, education and research in psychiatry are expected to change in this emerging digital world. PMID:15558872

  15. Channel Networks

    NASA Astrophysics Data System (ADS)

    Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio; Rigon, Riccardo

    This review proceeds from Luna Leopold's and Ronald Shreve's lasting accomplishments dealing with the study of random-walk and topologically random channel networks. According to the random perspective, which has had a profound influence on the interpretation of natural landforms, nature's resiliency in producing recurrent networks and landforms was interpreted to be the consequence of chance. In fact, central to models of topologically random networks is the assumption of equal likelihood of any tree-like configuration. However, a general framework of analysis exists that argues that all possible network configurations draining a fixed area are not necessarily equally likely. Rather, a probability P(s) is assigned to a particular spanning tree configuration, say s, which can be generally assumed to obey a Boltzmann distribution: P(s) % e^-H(s)/T, where T is a parameter and H(s) is a global property of the network configuration s related to energetic characters, i.e. its Hamiltonian. One extreme case is the random topology model where all trees are equally likely, i.e. the limit case for T6 4 . The other extreme case is T 6 0, and this corresponds to network configurations that tend to minimize their total energy dissipation to improve their likelihood. Networks obtained in this manner are termed optimal channel networks (OCNs). Observational evidence suggests that the characters of real river networks are reproduced extremely well by OCNs. Scaling properties of energy and entropy of OCNs suggest that large network development is likely to effectively occur at zero temperature (i.e. minimizing its Hamiltonian). We suggest a corollary of dynamic accessibility of a network configuration and speculate towards a thermodynamics of critical self-organization. We thus conclude that both chance and necessity are equally important ingredients for the dynamic origin of channel networks---and perhaps of the geometry of nature.

  16. Human factors evaluation of a dynamic channel depiction of navigation procedures in SVS displays

    NASA Astrophysics Data System (ADS)

    Pschierer, C.; Schiefele, J.; Howland, D.; Barraci, N.; Sindlinger, A.; Klingauf, U.

    2007-04-01

    Synthetic vision systems (SVS) are studied for some time to improve pilot's situational awareness and lower their workload. Early systems just displayed a virtual outside view of terrain, obstacles or airport elements as it could also be perceived through the cockpit windows in absence of haze, fog or any other factors impairing visibility. Required digital terrain, obstacle and airport databases have been developed and standardized by Jeppesen as part of the NASA Aviation Safety Program. Newer SVS displays also introduced different kinds of flight guidance symbology to help pilots to improve the overall flight precision. The method studied in this paper is to display navigation procedures in the form of guidance channels. First releases of the described system used static channels, generated once at the startup at the system or even offline. While this approach is very resource friendly for the avionics hardware, it does not consider the users, which want the system to respond to the current flight conditions dynamically. Therefore, a new application has been developed which generates both the general channel trajectory as well as the channel depiction in a fully dynamic way while the pilot flies a navigation procedure.

  17. An implantable 64-channel neural interface with reconfigurable recording and stimulation.

    PubMed

    Wheeler, Jesse J; Baldwin, Keith; Kindle, Alex; Guyon, Daniel; Nugent, Brian; Segura, Carlos; Rodriguez, John; Czarnecki, Andrew; Dispirito, Hailey J; Lachapelle, John; Parks, Philip D; Moran, James; Widge, Alik S; Dougherty, Darin D; Eskandar, Emad N

    2015-08-01

    Next generation implantable medical devices will have the potential to provide more precise and effective therapies through adaptive closed-loop controllers that combine sensing and stimulation across larger numbers of electrode channels. A major challenge in the design of such devices is balancing increased functionality and channel counts with the miniaturization required for implantation within small anatomical spaces. Customized therapies will require adaptive systems capable of tuning which channels are sensed and stimulated to overcome variability in patient-specific needs, surgical placement of electrodes, and chronic physiological responses. In order to address these challenges, we have designed a miniaturized implantable fully-reconfigurable front-end system that is integrated into the distal end of an 8-wire lead, enabling up to 64 electrodes to be dynamically configured for sensing and stimulation. Full reconfigurability is enabled by two custom 32×2 cross-point switch (CPS) matrix ASICs which can route any electrode to either an amplifier with reprogrammable bandwidth and integrated ADC or to one of two independent stimulation channels that can be driven through the lead. The 8-wire circuit includes a digital interface for robust communication as well as a charge-balanced powering scheme for enhanced safety. The system is encased in a hermetic package designed to fit within a 14 mm bur-hole in the skull for neuromodulation of the brain, but could easily be adapted to enhance therapies across a broad spectrum of applications. PMID:26738108

  18. High Rate Digital Demodulator ASIC

    NASA Technical Reports Server (NTRS)

    Ghuman, Parminder; Sheikh, Salman; Koubek, Steve; Hoy, Scott; Gray, Andrew

    1998-01-01

    The architecture of High Rate (600 Mega-bits per second) Digital Demodulator (HRDD) ASIC capable of demodulating BPSK and QPSK modulated data is presented in this paper. The advantages of all-digital processing include increased flexibility and reliability with reduced reproduction costs. Conventional serial digital processing would require high processing rates necessitating a hardware implementation in other than CMOS technology such as Gallium Arsenide (GaAs) which has high cost and power requirements. It is more desirable to use CMOS technology with its lower power requirements and higher gate density. However, digital demodulation of high data rates in CMOS requires parallel algorithms to process the sampled data at a rate lower than the data rate. The parallel processing algorithms described here were developed jointly by NASA's Goddard Space Flight Center (GSFC) and the Jet Propulsion Laboratory (JPL). The resulting all-digital receiver has the capability to demodulate BPSK, QPSK, OQPSK, and DQPSK at data rates in excess of 300 Mega-bits per second (Mbps) per channel. This paper will provide an overview of the parallel architecture and features of the HRDR ASIC. In addition, this paper will provide an over-view of the implementation of the hardware architectures used to create flexibility over conventional high rate analog or hybrid receivers. This flexibility includes a wide range of data rates, modulation schemes, and operating environments. In conclusion it will be shown how this high rate digital demodulator can be used with an off-the-shelf A/D and a flexible analog front end, both of which are numerically computer controlled, to produce a very flexible, low cost high rate digital receiver.

  19. Qualification of Safety-Related Software in Nuclear Power Plants

    SciTech Connect

    Johnson, G L

    2000-06-13

    Digital instrumentation and control systems have the potential of offering significant benefits over traditional analog systems in Nuclear Power Plant safety systems, but there are also significant difficulties in qualifying digital systems to the satisfaction of regulators. Digital systems differ in fundamental ways from analog systems. New methods for safety qualification, which take these differences into account, would ease the regulatory cost and promote use of digital systems. This paper offers a possible method for assisting in the analysis of digital system software, as one step in an improved qualification process.

  20. Multiple channel data acquisition system

    DOEpatents

    Crawley, H. Bert; Rosenberg, Eli I.; Meyer, W. Thomas; Gorbics, Mark S.; Thomas, William D.; McKay, Roy L.; Homer, Jr., John F.

    1990-05-22

    A multiple channel data acquisition system for the transfer of large amounts of data from a multiplicity of data channels has a plurality of modules which operate in parallel to convert analog signals to digital data and transfer that data to a communications host via a FASTBUS. Each module has a plurality of submodules which include a front end buffer (FEB) connected to input circuitry having an analog to digital converter with cache memory for each of a plurality of channels. The submodules are interfaced with the FASTBUS via a FASTBUS coupler which controls a module bus and a module memory. The system is triggered to effect rapid parallel data samplings which are stored to the cache memories. The cache memories are uploaded to the FEBs during which zero suppression occurs. The data in the FEBs is reformatted and compressed by a local processor during transfer to the module memory. The FASTBUS coupler is used by the communications host to upload the compressed and formatted data from the module memory. The local processor executes programs which are downloaded to the module memory through the FASTBUS coupler.

  1. Multiple channel data acquisition system

    DOEpatents

    Crawley, H.B.; Rosenberg, E.I.; Meyer, W.T.; Gorbics, M.S.; Thomas, W.D.; McKay, R.L.; Homer, J.F. Jr.

    1990-05-22

    A multiple channel data acquisition system for the transfer of large amounts of data from a multiplicity of data channels has a plurality of modules which operate in parallel to convert analog signals to digital data and transfer that data to a communications host via a FASTBUS. Each module has a plurality of submodules which include a front end buffer (FEB) connected to input circuitry having an analog to digital converter with cache memory for each of a plurality of channels. The submodules are interfaced with the FASTBUS via a FASTBUS coupler which controls a module bus and a module memory. The system is triggered to effect rapid parallel data samplings which are stored to the cache memories. The cache memories are uploaded to the FEBs during which zero suppression occurs. The data in the FEBs is reformatted and compressed by a local processor during transfer to the module memory. The FASTBUS coupler is used by the communications host to upload the compressed and formatted data from the module memory. The local processor executes programs which are downloaded to the module memory through the FASTBUS coupler. 25 figs.

  2. Simultaneous beta/gamma digital spectroscopy

    NASA Astrophysics Data System (ADS)

    Farsoni, Abdollah T.

    A state-of-the-art radiation detection system for simultaneous spectroscopy of beta-particles and gamma-rays has been developed. The system utilizes a triple-layer phoswich detector and a customized Digital Pulse Processor (DPP) built in our laboratory. The DPP board was designed to digitally capture the analog signal pulses and, following several digital preprocessing steps, transfer valid pulses to the host computer for further digital processing. A MATLAB algorithm was developed to digitally discriminate beta and gamma events and reconstruct separate beta and gamma-ray energy spectra with minimum crosstalk. The spectrometer proved to be an effective tool for recording separate beta and gamma-ray spectra from mixed radiation fields. The system as a beta-gamma spectrometer will have broad-ranging applications in nuclear non-proliferation, radioactive waste management, worker safety, systems reliability, dose assessment, and risk analysis.

  3. Scanning for Digitization Projects

    ERIC Educational Resources Information Center

    Wentzel, Larry

    2007-01-01

    Librarians and archivists find themselves facing the prospect of digitization. Everyone is doing it, everyone needs it. Discussions rage nationally and internationally concerning what to digitize and the best means to present and retain digital objects. Digitization is the act of making something digital, expressing a physical object "in numerical…

  4. Next generation digital GPS receiver

    NASA Astrophysics Data System (ADS)

    Frank, G. B.; Yakos, Michael D.

    1990-07-01

    The architecture and technology features of the next-generation (NGR) digital GPS receiver manufactured by Collins are described. The project's objective was to develop an advanced GPS receiver chipset with high antijam capabilities. The program, initiated in 1985, has provided the technology for miniature receiver products for both unmanned and manned vehicle applications. A two-channel version of the receiver is currently in full-scale development for tactical missile applications. A five-channel version is being tested and evaluated as a drop-in replacement for RCVR-3A, the US Department of Defense standard high dynamic receiver. The NGR design started with the digital signal processing architecture developed for the Defense Advanced Research Project Agency (DARPA) hand-held GPS receiver. Enhancements were made to improve the antijam and signal acquisition performance. Producible, qualifiable and cost-effective silicon monolithic microwave integrated circuits and semicustom digital technologies were used to develop the core GPS chipset. A system design approach was established to permit reuse of mature and validated GPS software.

  5. The Digital Data Acquisition System for the Russian VLBI Network of New Generation

    NASA Technical Reports Server (NTRS)

    Fedotov, Leonid; Nosov, Eugeny; Grenkov, Sergey; Marshalov, Dmitry

    2010-01-01

    The system consists of several identical channels of 1024 MHz bandwidth each. In each channel, the RF band is frequency-translated to the intermediate frequency range 1 - 2 GHz. Each channel consists of two parts: the digitizer and Mark 5C recorder. The digitizer is placed on the antenna close to the corresponding Low-Noise Amplifier output and consists of the analog frequency converter, ADC, and a device for digital processing of the signals using FPGA. In the digitizer the subdigitization on frequency of 2048 MHz is used. For producing narrow-band channels and to interface with existing data acquisition systems, the polyphase filtering with FPGA can be used. Digital signals are re-quantized to 2-bits in the FPGA and are transferred to an input of Mark 5C through a fiber line. The breadboard model of the digitizer is being tested, and the data acquisition system is being designed.

  6. Digital radiography in space.

    PubMed

    Hart, Rob; Campbell, Mark R

    2002-06-01

    With the permanent habitation of the International Space Station, the planning of longer duration exploration missions, and the possibility of space tourism, it is likely that digital radiography will be needed in the future to support medical care in space. Ultrasound is currently the medical imaging modality of choice for spaceflight. Digital radiography in space is limited because of prohibitive launch costs (in the region of $20,000/kg) that severely restrict the volume, weight, and power requirements of medical care hardware. Technological increases in radiography, a predicted ten-fold decrease in future launch costs, and an increasing clinical need for definitive medical care in space will drive efforts to expand the ability to provide medical care in space including diagnostic imaging. Normal physiological responses to microgravity, in conjunction with the high-risk environment of spaceflight, increase the risk of injury and could imply an extended recovery period for common injuries. The advantages of gravity on Earth, such as the stabilization of patients undergoing radiography and the drainage of fluids, which provide radiographic contrast, are unavailable in space. This creates significant difficulties in patient immobilization and radiographic positioning. Gravity-dependent radiological signs, such as lipohemarthrosis in knee and shoulder trauma, air or fluid levels in pneumoperitoneum, pleural effusion, or bowel obstruction, and the apical pleural edge in pneumothorax become unavailable. Impaired healing processes such as delayed callus formation following fracture will have implications on imaging, and recovery time lines are unknown. The confined nature of spacecraft and the economic impossibility of launching lead-based personal protective equipment present significant challenges to crew radiation safety. A modified, free-floating radiographic C-arm device equipped with a digital detector and utilizing teleradiology support is proposed as a

  7. DIGITAL ARCHITECTURE PROJECT PLAN

    SciTech Connect

    Thomas, Ken

    2014-09-01

    The objective of this project is to develop an industry consensus document on how to scope and implement the underlying information technology infrastructure that is needed to support a vast array of real-time digital technologies to improve NPP work efficiency, to reduce human error, to increase production reliability and to enhance nuclear safety. A consensus approach is needed because: • There is currently a wide disparity in nuclear utility perspectives and positions on what is prudent and regulatory-compliant for introducing certain digital technologies into the plant environment. For example, there is a variety of implementation policies throughout the industry concerning electromagnetic compatibility (EMC), cyber security, wireless communication coverage, mobile devices for workers, mobile technology in the control room, and so forth. • There is a need to effectively share among the nuclear operating companies the early experience with these technologies and other forms of lessons-learned. There is also the opportunity to take advantage of international experience with these technologies. • There is a need to provide the industry with a sense of what other companies are implementing, so that each respective company can factor this into their own development plans and position themselves to take advantage of new work methods as they are validated by the initial implementing companies. In the nuclear power industry, once a better work practice has been proven, there is a general expectation that the rest of the industry will adopt it. However, the long-lead time of information technology infrastructure could prove to be a delaying factor. A secondary objective of this effort is to provide a general understanding of the incremental investment that would be required to support the targeted digital technologies, in terms of an incremental investment over current infrastructure. This will be required for business cases to support the adoption of these new

  8. High Density Digital Data Storage System

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth D., II; Gray, David L.; Rowland, Wayne D.

    1991-01-01

    The High Density Digital Data Storage System was designed to provide a cost effective means for storing real-time data from the field-deployable digital acoustic measurement system. However, the high density data storage system is a standalone system that could provide a storage solution for many other real time data acquisition applications. The storage system has inputs for up to 20 channels of 16-bit digital data. The high density tape recorders presently being used in the storage system are capable of storing over 5 gigabytes of data at overall transfer rates of 500 kilobytes per second. However, through the use of data compression techniques the system storage capacity and transfer rate can be doubled. Two tape recorders have been incorporated into the storage system to produce a backup tape of data in real-time. An analog output is provided for each data channel as a means of monitoring the data as it is being recorded.

  9. Self-Digitization of Sample Volumes

    PubMed Central

    Cohen, Dawn E.; Schneider, Thomas; Wang, Michelle; Chiu, Daniel T.

    2010-01-01

    This paper describes a very simple and robust microfluidic device for digitizing samples into an array of discrete volumes. The device is based on an inherent fluidic phenomenon, where an incoming aqueous sample divides itself into an array of chambers that have been primed with an immiscible phase. Self-digitization of sample volumes results from the interplay between fluidic forces, interfacial tension, channel geometry, and the final stability of the digitized samples in the chambers. Here we describe experiments and simulations that were used to characterize these parameters and the conditions under which the self-digitization process occurred. Unlike existing methods used to partition samples into array, our method is able to digitize 100% of a sample into a localized array without any loss of sample volume. The final volume of the discretized sample at each location is defined by the geometry and size of each chamber. Thus, we can form an array of samples with varying but predefined volumes. We exploited this feature to separate the crystal growth of otherwise concomitant polymorphs from a single solution. Additionally, we demonstrated the removal of the digitized samples from the chambers for downstream analysis, as well as the addition of reagents to the digitized samples. We believe this simple method will be useful in a broad range of applications where a large array of discretized samples is required, including digital PCR, single-cell analysis, and cell-based drug screening. PMID:20550137

  10. Multiple channel programmable coincidence counter

    DOEpatents

    Arnone, Gaetano J.

    1990-01-01

    A programmable digital coincidence counter having multiple channels and featuring minimal dead time. Neutron detectors supply electrical pulses to a synchronizing circuit which in turn inputs derandomized pulses to an adding circuit. A random access memory circuit connected as a programmable length shift register receives and shifts the sum of the pulses, and outputs to a serializer. A counter is input by the adding circuit and downcounted by the seralizer, one pulse at a time. The decoded contents of the counter after each decrement is output to scalers.

  11. NIR-green-blue high-resolution digital images for assessement of winter cover crop biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many small unmanned aerial systems use true-color digital cameras for remote sensing. For some cameras, only the red channel is sensitive to near-infrared (NIR) light; we attached a custom red-blocking filter to a digital camera to obtain NIR-green-blue digital images. One advantage of this low-co...

  12. Digital demodulator

    NASA Technical Reports Server (NTRS)

    Shull, T. A. (Inventor)

    1982-01-01

    A digital demodulator for converting pulse code modulated data from phase shift key (PSK) to non return to zero (NRZ) and to biphase data is described. The demodulator is composed of standard integrated logic circuits. The key to the demodulation function is a pair of cross coupled one shot multivibrators and which with a flip-flop produce the NRZ-L is all that is required, the circuitry is greatly simplified and the 2(v) times bit rate contraint can be removed from the carrier. A flip-flop, an OR gate, and AND gate and a binary counter generate the bit rate clock (BTCK) for the NRZ-L. The remainder of the circuitry is for converting the NRZ-L and BTCK into biphase data. The device was designed for use in the space shuttle bay environment measurements.

  13. Digital Avionics

    NASA Technical Reports Server (NTRS)

    Koelbl, Terry G.; Ponchak, Denise; Lamarche, Teresa

    2002-01-01

    The field of digital avionics experienced another year of important advances in civil aviation, military systems, and space applications. As a result of the events of 9/11/2001, NASA has pursued activities to apply its aerospace technologies toward improved aviation security. Both NASA Glenn Research Center and Langley Research Center have performed flight research demonstrations using advanced datalink concepts to transmit live pictures from inside a jetliner, and to downlink the contents of the plane's 'black box' recorder in real time. The U.S. Navy and General Electric demonstrated survivable engine control (SEC) algorithms during engine ground tests at the Weapons Survivability Laboratory at China Lake. The scientists at Boeing Satellite Systems advanced the field of stellar inertial technology with the development of a new method for positioning optical star trackers on satellites.

  14. Digital Avionics

    NASA Technical Reports Server (NTRS)

    Koelbl, Terry G.; Ponchak, Denise; Lamarche, Teresa

    2003-01-01

    Digital Avionics activities played an important role in the advancements made in civil aviation, military systems, and space applications. This document profiles advances made in each of these areas by the aerospace industry, NASA centers, and the U.S. military. Emerging communication technologies covered in this document include Internet connectivity onboard aircraft, wireless broadband communication for aircraft, and a mobile router for aircraft to communicate in multiple communication networks over the course of a flight. Military technologies covered in this document include avionics for unmanned combat air vehicles and microsatellites, and head-up displays. Other technologies covered in this document include an electronic flight bag for the Boeing 777, and surveillance systems for managing airport operations.

  15. Digital communication systems

    NASA Astrophysics Data System (ADS)

    Peebles, Peyton Z., Jr.

    The fundamental principles of digital communication and the design of practical digital communication systems are explored in an introductory textbook for senior and graduate students of electrical engineering. Chapters are devoted to sampling principles, baseband digital waveforms, baseband digital systems, bandpass binary digital systems, and M-ary digital systems. Deterministic signals, networks, and random-signal theory are reviewed in extensive appendices, and graphs, flow charts, diagrams, and problems are provided.

  16. Vaccine Safety

    MedlinePlus

    ... During Pregnancy Frequently Asked Questions about Vaccine Recalls Historical Vaccine Safety Concerns FAQs about GBS and Menactra ... CISA Resources for Healthcare Professionals Evaluation Current Studies Historical Background 2001-12 Publications Technical Reports Vaccine Safety ...

  17. Quantization effects in radiation spectroscopy based on digital pulse processing

    SciTech Connect

    Jordanov, V. T.; Jordanova, K. V.

    2011-07-01

    Radiation spectra represent inherently quantization data in the form of stacked channels of equal width. The spectrum is an experimental measurement of the discrete probability density function (PDF) of the detector pulse heights. The quantization granularity of the spectra depends on the total number of channels covering the full range of pulse heights. In analog pulse processing the total number of channels is equal to the total digital values produced by a spectroscopy analog-to-digital converter (ADC). In digital pulse processing each detector pulse is sampled and quantized by a fast ADC producing certain number of quantized numerical values. These digital values are linearly processed to obtain a digital quantity representing the peak of the digitally shaped pulse. Using digital pulse processing it is possible to acquire a spectrum with the total number of channels greater than the number of ADC values. Noise and sample averaging are important in the transformation of ADC quantized data into spectral quantized data. Analysis of this transformation is performed using an area sampling model of quantization. Spectrum differential nonlinearity (DNL) is shown to be related to the quantization at low noise levels and small number of averaged samples. Theoretical analysis and experimental measurements are used to obtain the condition to minimize the DNL due to quantization. (authors)

  18. 78 FR 27443 - Advisory Committee on Reactor Safeguards (ACRS); Meeting of the ACRS Subcommittee on Digital I&C...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-10

    ... computer software in safety systems of nuclear power plants: 1. Proposed Revision 1 to Regulatory Guide 1.169 (DG-1206), ``Configuration Management Plans for Digital Computer Software Used in Safety Systems... Documentation for Digital Computer Software Used in Safety Systems of Nuclear Power Plants;'' 3....

  19. Safety Handbook.

    ERIC Educational Resources Information Center

    Montgomery County Public Schools, Rockville, MD.

    Safety policies, procedures, and related information are presented in this manual to assist school personnel in a continuing program of accident prevention. Chapter 1 discusses safety education and accident prevention in general. Chapter 2 covers traffic regulations relating to school safety patrols, school bus transportation, bicycles, and…

  20. Can We Teach Digital Natives Digital Literacy?

    ERIC Educational Resources Information Center

    Ng, Wan

    2012-01-01

    In recent years, there has been much debate about the concept of digital natives, in particular the differences between the digital natives' knowledge and adoption of digital technologies in informal versus formal educational contexts. This paper investigates the knowledge about educational technologies of a group of undergraduate students…

  1. 47 CFR 80.459 - Digital selective calling.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Digital selective calling. 80.459 Section 80.459 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Public Coast Stations Use of Telegraphy § 80.459 Digital...

  2. 47 CFR 80.459 - Digital selective calling.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Digital selective calling. 80.459 Section 80.459 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Public Coast Stations Use of Telegraphy § 80.459 Digital...

  3. Teaching and communicating science in a digital age

    PubMed Central

    Scott, Graham

    2015-01-01

    We assume that digital literacy and access are common to all who teach and communicate their science and to their audiences. We also assume that our digital communication is effective and that by using digital technologies learning experiences are enhanced. But are these reasonable assumptions to make? This F1000Research channel brings together papers developed from presentations made at Teaching and Communicating Science in a Digital Age, a Society for Experimental Biology symposium involving Higher Education Professionals from across the globe to reflect upon the impact that digital technologies have and will have upon aspects of the communication of science. Here I share some thoughts on the discussion that took place and on the papers collated through this channel. PMID:26097691

  4. Digital photorefraction

    NASA Astrophysics Data System (ADS)

    Costa, Manuel F.; Jorge, Jorge M.

    1997-12-01

    The early evaluation of the visual status of human infants is of a critical importance. It is of utmost importance to the development of the child's visual system that she perceives clear, focused, retinal images. Furthermore if the refractive problems are not corrected in due time amblyopia may occur. Photorefraction is a non-invasive clinical tool rather convenient for application to this kind of population. A qualitative or semi-quantitative information about refractive errors, accommodation, strabismus, amblyogenic factors and some pathologies (cataracts) can the easily obtained. The photorefraction experimental setup we established using new technological breakthroughs on the fields of imaging devices, image processing and fiber optics, allows the implementation of both the isotropic and eccentric photorefraction approaches. Essentially both methods consist on delivering a light beam into the eyes. It is refracted by the ocular media, strikes the retina, focusing or not, reflects off and is collected by a camera. The system is formed by one CCD color camera and a light source. A beam splitter in front of the camera's objective allows coaxial illumination and observation. An optomechanical system also allows eccentric illumination. The light source is a flash type one and is synchronized with the camera's image acquisition. The camera's image is digitized displayed in real time. Image processing routines are applied for image's enhancement and feature extraction.

  5. Digital photorefraction

    NASA Astrophysics Data System (ADS)

    Costa, Manuel F. M.; Jorge, Jorge M.

    1998-01-01

    The early evaluation of the visual status of human infants is of a critical importance. It is of utmost importance to the development of the child's visual system that she perceives clear, focused, retinal images. Furthermore if the refractive problems are not corrected in due time amblyopia may occur. Photorefraction is a non-invasive clinical tool rather convenient for application to this kind of population. A qualitative or semi-quantitative information about refractive errors, accommodation, strabismus, amblyogenic factors and some pathologies (cataracts) can the easily obtained. The photorefraction experimental setup we established using new technological breakthroughs on the fields of imaging devices, image processing and fiber optics, allows the implementation of both the isotropic and eccentric photorefraction approaches. Essentially both methods consist on delivering a light beam into the eyes. It is refracted by the ocular media, strikes the retina, focusing or not, reflects off and is collected by a camera. The system is formed by one CCD color camera and a light source. A beam splitter in front of the camera's objective allows coaxial illumination and observation. An optomechanical system also allows eccentric illumination. The light source is a flash type one and is synchronized with the camera's image acquisition. The camera's image is digitized displayed in real time. Image processing routines are applied for image's enhancement and feature extraction.

  6. Green Channel Guiding Denoising on Bayer Image

    PubMed Central

    Zhang, Maojun

    2014-01-01

    Denoising is an indispensable function for digital cameras. In respect that noise is diffused during the demosaicking, the denoising ought to work directly on bayer data. The difficulty of denoising on bayer image is the interlaced mosaic pattern of red, green, and blue. Guided filter is a novel time efficient explicit filter kernel which can incorporate additional information from the guidance image, but it is still not applied for bayer image. In this work, we observe that the green channel of bayer mode is higher in both sampling rate and Signal-to-Noise Ratio (SNR) than the red and blue ones. Therefore the green channel can be used to guide denoising. This kind of guidance integrates the different color channels together. Experiments on both actual and simulated bayer images indicate that green channel acts well as the guidance signal, and the proposed method is competitive with other popular filter kernel denoising methods. PMID:24741370

  7. Benefits of Digital Equipment Generic Qualification Activities

    SciTech Connect

    Thomas, James E.; Steiman, Samuel C.

    2002-07-01

    As a result of nuclear power plant instrumentation and control obsolescence issues, there have been numerous activities during recent years relating to the qualification of digital equipment. Some of these activities have been 'generic' in nature in that the qualification was not limited to plant specific applications, but was intended to cover a broad base of potential applications of the digital equipment. These generic qualifications have been funded by equipment manufacturers and by utility groups and organizations. The generic activities sponsored by the Electric Power Research Institute (EPRI) have been pilot projects for an overall generic qualification approach. The primary benefit resulting from the generic qualification work to date is that a number of digital platforms and digital devices are now available for use in various nuclear safety-related applications. Many of the tests and evaluations necessary to support plant specific applications have been completed. The amount of data and documentation that each utility must develop on a case by case basis has been significantly reduced. There are also a number of additional benefits resulting from these industry efforts. The challenges and difficulties in qualifying digital equipment for safety-related applications are now more clearly understood. EPRI has published a lessons learned document (EPRI Report 1001452, Generic Qualification of Commercial Grade Digital Devices: Lessons Learned from Initial Pilots, which covers several different qualification areas, including device selection, project planning, vendor surveys and design reviews, and electromagnetic compatibility (EMC) qualification. Application of the experience and lessons learned from the EPRI pilot activities should help reduce the effort and cost required for future qualification work. Most generic qualification activities for commercial equipment have been conducted using the approach of EPRI TR-106439, Guideline on Evaluation and Acceptance

  8. Optical transmission modules for multi-channel superconducting quantum interference device readouts

    SciTech Connect

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

    2013-12-15

    We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz.

  9. Optical transmission modules for multi-channel superconducting quantum interference device readouts

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz.

  10. Optical transmission modules for multi-channel superconducting quantum interference device readouts.

    PubMed

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

    2013-12-01

    We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz. PMID:24387470

  11. Research highlights: digital assays on chip.

    PubMed

    Kim, Donghyuk; Wei, Qingshan; Kong, Janay Elise; Ozcan, Aydogan; Di Carlo, Dino

    2015-01-01

    The ability to break up a volume of fluid into smaller pieces that are confined or separated to prevent molecular communication/transport is a key capability intrinsic to microfluidic systems. This capability has been used to develop or implement digital versions of traditional molecular analysis assays, including digital PCR and digital immunoassays/ELISA. In these digital versions, the concentration of the target analyte is in a range such that, when sampled into smaller fluid volumes, either a single molecule or no molecule may be present. Subsequent amplification is sensitive enough to obtain a digital readout of the presence of these target molecules. Advantages of such approaches that are claimed include quantification without calibration and robustness to variations in reaction conditions or times because the digital readout is less sensitive to absolute signal intensity levels. Weaknesses of digital approaches include a lower dynamic range of concentrations over which the assay is sensitive, which depends on the total volume that can be analyzed. We highlight recent efforts to expand the dynamic range of digital assays based on exploiting reaction/diffusion phenomena. A side-by-side study that evaluates the strengths of digital assays reveals that the majority of these claims are supported, with specific caveats. Finally, we highlight approaches to apply digital assays to analyze new types of reactions, including the active transport of protons across membranes by ATPases at the single protein level - perhaps opening up new biophysical understanding and screening opportunities, similar to widely deployed single-molecule ion channel analysis. PMID:25410901

  12. H. Sapiens Digital: From Digital Immigrants and Digital Natives to Digital Wisdom

    ERIC Educational Resources Information Center

    Prensky, Marc

    2009-01-01

    As we move further into the 21st century, the digital native/digital immigrant paradigm created by Marc Prensky in 2001 is becoming less relevant. In this article, Prensky suggests that we should focus instead on the development of what he calls "digital wisdom." Arguing that digital technology can make us not just smarter but truly wiser, Prensky…

  13. National Safety Council

    MedlinePlus

    ... Introduction Safety Management Systems Workplace Safety Consulting Employee Perception Surveys Research Journey to Safety Excellence Join the ... Safety Safety Management Systems Workplace Safety Consulting Employee Perception Surveys Research Journey to Safety Excellence Join the ...

  14. Percutaneous Release of Trigger Fingers: Comparing Multiple Digits with Single Digit Involvement

    PubMed Central

    Saremi, Hossein; Hakhamaneshi, Elham; Rabiei, Mohamad Ali Seif

    2016-01-01

    Background: To evaluate safety and efficacy of percutaneous release of trigger finger in multiple digits involvement in comparison with single digit involvement. Method: A number of 100 patients (131 fingers) were treated by percutaneous release and divided into two groups: single digit (group A) and multiple digits (group B). They were followed up for one year. Success rate, pain, complications and duration of analgesic use were studied and then compared in both groups. Results: All patients in both groups were treated successfully without any recurrence in a one-year follow-up. No complication was observed, but postoperative duration of pain was significantly different between the two groups. Period of painkiller use was also different between the two groups. Conclusion: Percutaneous release is a safe and effective treatment for trigger fingers even if multiple digits are involved. It is also safe in thumb and index finger involvement and diabetic patients.

  15. A 64-channel transmitter for investigating parallel transmit MRI.

    PubMed

    Ke Feng; Hollingsworth, N A; McDougall, M P; Wright, S M

    2012-08-01

    Multiple channel radiofrequency (RF) transmitters are being used in magnetic resonance imaging to investigate a number of active research topics, including transmit SENSE and B(1) shimming. Presently, the cost and availability of multiple channel transmitters restricts their use to relatively few sites. This paper describes the development and testing of a relatively inexpensive transmit system that can be easily duplicated by users with a reasonable level of RF hardware design experience. The system described here consists of 64 channels, each with 100 W peak output level. The hardware is modular at the level of four channels, easily accommodating larger or smaller channel counts. Unique aspects of the system include the use of vector modulators to replace more complex IQ direct digital modulators, 100 W MOSFET RF amplifiers with partial microstrip matching networks, and the use of digital potentiometers to replace more complex and costly digital-to-analog converters to control the amplitude and phase of each channel. Although mainly designed for B(1) shimming, the system is capable of dynamic modulation necessary for transmit SENSE by replacing the digital potentiometers controlling the vector modulators with commercially available analog output boards. The system design is discussed in detail and bench and imaging data are shown, demonstrating the ability to perform phase and amplitude control for B(1) shimming as well as dynamic modulation for transmitting complex RF pulses. PMID:22552545

  16. Digital Sensor Technology

    SciTech Connect

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  17. Digital signal processor and processing method for GPS receivers

    NASA Technical Reports Server (NTRS)

    Thomas, Jr., Jess B. (Inventor)

    1989-01-01

    A digital signal processor and processing method therefor for use in receivers of the NAVSTAR/GLOBAL POSITIONING SYSTEM (GPS) employs a digital carrier down-converter, digital code correlator and digital tracking processor. The digital carrier down-converter and code correlator consists of an all-digital, minimum bit implementation that utilizes digital chip and phase advancers, providing exceptional control and accuracy in feedback phase and in feedback delay. Roundoff and commensurability errors can be reduced to extremely small values (e.g., less than 100 nanochips and 100 nanocycles roundoff errors and 0.1 millichip and 1 millicycle commensurability errors). The digital tracking processor bases the fast feedback for phase and for group delay in the C/A, P.sub.1, and P.sub.2 channels on the L.sub.1 C/A carrier phase thereby maintaining lock at lower signal-to-noise ratios, reducing errors in feedback delays, reducing the frequency of cycle slips and in some cases obviating the need for quadrature processing in the P channels. Simple and reliable methods are employed for data bit synchronization, data bit removal and cycle counting. Improved precision in averaged output delay values is provided by carrier-aided data-compression techniques. The signal processor employs purely digital operations in the sense that exactly the same carrier phase and group delay measurements are obtained, to the last decimal place, every time the same sampled data (i.e., exactly the same bits) are processed.

  18. A digital-receiver for the MurchisonWidefield Array

    NASA Astrophysics Data System (ADS)

    Prabu, Thiagaraj; Srivani, K. S.; Roshi, D. Anish; Kamini, P. A.; Madhavi, S.; Emrich, David; Crosse, Brian; Williams, Andrew J.; Waterson, Mark; Deshpande, Avinash A.; Shankar, N. Udaya; Subrahmanyan, Ravi; Briggs, Frank H.; Goeke, Robert F.; Tingay, Steven J.; Johnston-Hollitt, Melanie; R, Gopalakrishna M.; Morgan, Edward H.; Pathikulangara, Joseph; Bunton, John D.; Hampson, Grant; Williams, Christopher; Ord, Stephen M.; Wayth, Randall B.; Kumar, Deepak; Morales, Miguel F.; deSouza, Ludi; Kratzenberg, Eric; Pallot, D.; McWhirter, Russell; Hazelton, Bryna J.; Arcus, Wayne; Barnes, David G.; Bernardi, Gianni; Booler, T.; Bowman, Judd D.; Cappallo, Roger J.; Corey, Brian E.; Greenhill, Lincoln J.; Herne, David; Hewitt, Jacqueline N.; Kaplan, David L.; Kasper, Justin C.; Kincaid, Barton B.; Koenig, Ronald; Lonsdale, Colin J.; Lynch, Mervyn J.; Mitchell, Daniel A.; Oberoi, Divya; Remillard, Ronald A.; Rogers, Alan E.; Salah, Joseph E.; Sault, Robert J.; Stevens, Jamie B.; Tremblay, S.; Webster, Rachel L.; Whitney, Alan R.; Wyithe, Stuart B.

    2015-03-01

    An FPGA-based digital-receiver has been developed for a low-frequency imaging radio interferometer, the Murchison Widefield Array (MWA). The MWA, located at the Murchison Radio-astronomy Observatory (MRO) in Western Australia, consists of 128 dual-polarized aperture-array elements (tiles) operating between 80 and 300 MHz, with a total processed bandwidth of 30.72 MHz for each polarization. Radio-frequency signals from the tiles are amplified and band limited using analog signal conditioning units; sampled and channelized by digital-receivers. The signals from eight tiles are processed by a single digital-receiver, thus requiring 16 digital-receivers for the MWA. The main function of the digital-receivers is to digitize the broad-band signals from each tile, channelize them to form the sky-band, and transport it through optical fibers to a centrally located correlator for further processing. The digital-receiver firmware also implements functions to measure the signal power, perform power equalization across the band, detect interference-like events, and invoke diagnostic modes. The digital-receiver is controlled by high-level programs running on a single-board-computer. This paper presents the digital-receiver design, implementation, current status, and plans for future enhancements.

  19. Consumer protection act for digital products

    NASA Astrophysics Data System (ADS)

    Hampel, Viktor E.

    1996-03-01

    This report proposes a `Consumer Protection Act for Digital Products' to support electronic commerce and to control the increasing abuse and lack of security on the national information highways. Patterned after the `Food and Drug Act of 1906 (21 USC)' and subsequent legislation, a new agency similar to that of the FDA would have the authority `to develop administrative policy with regard to the safety, effectiveness, and labeling of digital products and their communications for human use, and to review and evaluate new applications of such products.' Specifically, it is proposed that standards, originally developed by the defense industry for the labeling, enveloping, and authentication of digital products delivered to the Government, be extended to promote global electronic commerce by protecting the intellectual property rights of producers, establishing their liability for the end-use of digital products, and give consumers means for informed decision making and purchase.

  20. Digitally Calibrated TR Modules Enabling Real-Time Beamforming SweepSAR Architectures

    NASA Technical Reports Server (NTRS)

    Hoffman, James P.; Veilleux, Louse A.; Peral, Eva; Chuang, Chung-Lun; Shaffer, Scott J.

    2013-01-01

    SweepSAR, a novel radar architecture that depends on a DBF (digital beamforming) array, requires calibration accuracies that are order(s) of magnitude greater than is possible with traditional techniques, such as a priori characterization of TR (transmit/receive) modules in thermal vacuum chambers, or simple loop-back of the calibration signal. The advantages of a SweepSAR architecture are so great that it is worth applying significant resources to calibration efforts. Due to the nature of the DBF, each channel contains a digitizer and very powerful digital processor. Each channel can independently digitize (with the digitizer) and analyze (with the processor) its channel's unique calibration signal, and extract the relevant calibration parameters, namely channel gain and channel phase delay commonly referred to as the gain (or amplitude) and phase of the channel. Using the processor, each channel's gain and phase can theoretically be estimated with arbitrary precision through averaging a sufficiently large number of samples. Systematic errors and the changing gain and phase of the channels, typically due to temperature drifts, limits how long the averaging can occur, which limits the precision of the calibration estimate. However, results indicate that calibration knowledge of both the transmit and receive chains of each TR module can be improved by one or two orders of magnitude. Due to the digital nature of the receiver data, the channel's gain and phase may be corrected by a similar amount, while the transmit chain can only be corrected in a traditional manner. To implement Sweep SAR, the order of magnitude improvement in the knowledge of the channel's gain and phase is needed, and the control of the receiver to a similar level is required. Inherent to the DBF array is the individual digitization of each of the array's receiver channels. Current systems typically combine all of the analog signals in the array into one or two analog channels, which are then

  1. 47 CFR 95.29 - Channels available.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Channels available. 95.29 Section 95.29 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... population as defined in the U.S. Census of Population, 1960, Vol. 1, Table 23, page 50 that were...

  2. 47 CFR 95.29 - Channels available.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Channels available. 95.29 Section 95.29 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... population as defined in the U.S. Census of Population, 1960, Vol. 1, Table 23, page 50 that were...

  3. 47 CFR 95.29 - Channels available.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Channels available. 95.29 Section 95.29 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... population as defined in the U.S. Census of Population, 1960, Vol. 1, Table 23, page 50 that were...

  4. 47 CFR 95.29 - Channels available.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Channels available. 95.29 Section 95.29 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... population as defined in the U.S. Census of Population, 1960, Vol. 1, Table 23, page 50 that were...

  5. 47 CFR 95.7 - Channel sharing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Channel sharing. 95.7 Section 95.7 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... this problem by mutually satisfactory arrangements. If the licensees are unable to do so, the FCC...

  6. 47 CFR 95.7 - Channel sharing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Channel sharing. 95.7 Section 95.7 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... this problem by mutually satisfactory arrangements. If the licensees are unable to do so, the FCC...

  7. Mark 3 wideband digital recorder in perspective

    NASA Technical Reports Server (NTRS)

    Hinteregger, H. F.

    1980-01-01

    The tape recorder used for the Mark 3 data acquisition and processing system is compared with earlier very long baseline interferometry recorders. Wideband 33-1/3 kbpi digital channel characteristics of instrumentation recorders and of a modern video cassette recorder are illustrated. Factors which influenced selection of the three major commercial components (transport, heads, and tape) are discussed. A brief functional description and the reasons for development of efficient signal electronics and necessary auxiliary control electronics are given. The design and operation of a digital bit synchronizer is illustrated as an example of the high degree of simplicity achieved.

  8. High-Density Digital Data Storage System

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth D.; Gray, David L.

    1995-01-01

    High-density digital data storage system designed for cost-effective storage of large amounts of information acquired during experiments. System accepts up to 20 channels of 16-bit digital data with overall transfer rates of 500 kilobytes per second. Data recorded on 8-millimeter magnetic tape in cartridges, each capable of holding up to five gigabytes of data. Each cartridge mounted on one of two tape drives. Operator chooses to use either or both of drives. One drive used for primary storage of data while other can be used to make a duplicate record of data. Alternatively, other drive serves as backup data-storage drive when primary one fails.

  9. Digital exploitation of synthetic aperture radar

    NASA Technical Reports Server (NTRS)

    Wagner, H. L.; Shuchman, R. A.

    1977-01-01

    A digital processing and analysis scheme for use with digitized synthetic aperture radar data was developed. Using data from a four channel system, the imagery is preprocessed using specially designed software and then analyzed using preexisting facilities originally intended for use with MSS type data. Geometric and radiometric correction may be performed if desired, as well as classification analysis, Fast Fourier transform, filtering and level slice and display functions. The system provides low cost output in real time, permitting interactive imagery analysis. System information flow diagrams as well as sample output products are shown.

  10. Parallel digital modem using multirate digital filter banks

    NASA Technical Reports Server (NTRS)

    Sadr, Ramin; Vaidyanathan, P. P.; Raphaeli, Dan; Hinedi, Sami

    1994-01-01

    A new class of architectures for an all-digital modem is presented in this report. This architecture, referred to as the parallel receiver (PRX), is based on employing multirate digital filter banks (DFB's) to demodulate, track, and detect the received symbol stream. The resulting architecture is derived, and specifications are outlined for designing the DFB for the PRX. The key feature of this approach is a lower processing rate then either the Nyquist rate or the symbol rate, without any degradation in the symbol error rate. Due to the freedom in choosing the processing rate, the designer is able to arbitrarily select and use digital components, independent of the speed of the integrated circuit technology. PRX architecture is particularly suited for high data rate applications, and due to the modular structure of the parallel signal path, expansion to even higher data rates is accommodated with each. Applications of the PRX would include gigabit satellite channels, multiple spacecraft, optical links, interactive cable-TV, telemedicine, code division multiple access (CDMA) communications, and others.

  11. Digital Audio Radio Field Tests

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1997-01-01

    Radio history continues to be made at the NASA Lewis Research Center with the beginning of phase two of Digital Audio Radio testing conducted by the Consumer Electronic Manufacturers Association (a sector of the Electronic Industries Association and the National Radio Systems Committee) and cosponsored by the Electronic Industries Association and the National Association of Broadcasters. The bulk of the field testing of the four systems should be complete by the end of October 1996, with results available soon thereafter. Lewis hosted phase one of the testing process, which included laboratory testing of seven proposed digital audio radio systems and modes (see the following table). Two of the proposed systems operate in two modes, thus making a total of nine systems for testing. These nine systems are divided into the following types of transmission: in-band on channel (IBOC), in-band adjacent channel (IBAC), and new bands - the L-band (1452 to 1492 MHz) and the S-band (2310 to 2360 MHz).

  12. A Digital Motion Control System for Large Telescopes

    NASA Astrophysics Data System (ADS)

    Hunter, T. R.; Wilson, R. W.; Kimberk, R.; Leiker, P. S.

    2001-05-01

    We have designed and programmed a digital motion control system for large telescopes, in particular, the 6-meter antennas of the Submillimeter Array on Mauna Kea. The system consists of a single robust, high-reliability microcontroller board which implements a two-axis velocity servo while monitoring and responding to critical safety parameters. Excellent tracking performance has been achieved with this system (0.3 arcsecond RMS at sidereal rate). The 24x24 centimeter four-layer printed circuit board contains a multitude of hardware devices: 40 digital inputs (for limit switches and fault indicators), 32 digital outputs (to enable/disable motor amplifiers and brakes), a quad 22-bit ADC (to read the motor tachometers), four 16-bit DACs (that provide torque signals to the motor amplifiers), a 32-LED status panel, a serial port to the LynxOS PowerPC antenna computer (RS422/460kbps), a serial port to the Palm Vx handpaddle (RS232/115kbps), and serial links to the low-resolution absolute encoders on the azimuth and elevation axes. Each section of the board employs independent ground planes and power supplies, with optical isolation on all I/O channels. The processor is an Intel 80C196KC 16-bit microcontroller running at 20MHz on an 8-bit bus. This processor executes an interrupt-driven, scheduler-based software system written in C and assembled into an EPROM with user-accessible variables stored in NVSRAM. Under normal operation, velocity update requests arrive at 100Hz from the position-loop servo process running independently on the antenna computer. A variety of telescope safety checks are performed at 279Hz including routine servicing of a 6 millisecond watchdog timer. Additional ADCs onboard the microcontroller monitor the winding temperature and current in the brushless three-phase drive motors. The PID servo gains can be dynamically changed in software. Calibration factors and software filters can be applied to the tachometer readings prior to the application of

  13. Equalization in redundant channels

    NASA Technical Reports Server (NTRS)

    Tulpule, Bhalchandra R. (Inventor); Collins, Robert E. (Inventor); Cominelli, Donald F. (Inventor); O'Neill, Richard D. (Inventor)

    1988-01-01

    A miscomparison between a channel's configuration data base and a voted system configuration data base in a redundant channel system having identically operating, frame synchronous channels triggers autoequalization of the channel's historical signal data bases in a hierarchical, chronological manner with that of a correctly operating channel. After equalization, symmetrization of the channel's configuration data base with that of the system permits upgrading of the previously degraded channel to full redundancy. An externally provided equalization command, e.g., manually actuated, can also trigger equalization.

  14. Safety control circuit for a neutronic reactor

    DOEpatents

    Ellsworth, Howard C.

    2004-04-27

    A neutronic reactor comprising an active portion containing material fissionable by neutrons of thermal energy, means to control a neutronic chain reaction within the reactor comprising a safety device and a regulating device, a safety device including means defining a vertical channel extending into the reactor from an aperture in the upper surface of the reactor, a rod containing neutron-absorbing materials slidably disposed within the channel, means for maintaining the safety rod in a withdrawn position relative to the active portion of the reactor including means for releasing said rod on actuation thereof, a hopper mounted above the active portion of the reactor having a door disposed at the bottom of the hopper opening into the vertical channel, a plurality of bodies of neutron-absorbing materials disposed within the hopper, and means responsive to the failure of the safety rod on actuation thereof to enter the active portion of the reactor for opening the door in the hopper.

  15. A FIM Study to Assess Safety and Exposure of Inhaled Single Doses of AP301—A Specific ENaC Channel Activator for the Treatment of Acute Lung Injury

    PubMed Central

    Schwameis, Richard; Eder, Sandra; Pietschmann, Helmut; Fischer, Bernhard; Mascher, Hermann; Tzotzos, Susan; Fischer, Hendrik; Lucas, Rudolf; Zeitlinger, Markus; Hermann, Robert

    2014-01-01

    AP301 is an activator of ENaC-mediated Na+ uptake for the treatment of pulmonary permeability edema in acute respiratory distress syndrome (ARDS). The purpose of this “first-in-man” study was to examine local and systemic safety and systemic exposure of ascending single doses of AP301, when inhaled by healthy male subjects. In a double-blind, placebo-controlled study, 48 healthy male subjects were randomized to 6 ascending dose groups (single doses up to 120 mg) of 8 subjects each (3:1 randomization of AP301: placebo). Serial assessments included spirometry, exhaled nitric oxide (eNO), vital signs, ECG, safety laboratory, adverse events (AE), and blood samples for the quantification of AP301 in plasma. Descriptive statistics was applied. All 48 subjects received treatment, and completed the study as per protocol. No serious, local (e.g., hoarseness, cough, bronchospasm), or dose-limiting AEs were noted. None of the assessments indicated notable dose or time-related alterations of safety outcomes. Observed AP301 systemic exposure levels were very low, with mean Cmax values of <2.5 ng/mL in the highest dose groups. Inhaled AP301 single doses up to 120 mg were safe and well tolerated by healthy male subjects. Distribution of inhaled AP301 was largely confined to the lung, as indicated by very low AP301 systemic exposure levels. PMID:24515273

  16. 47 CFR 95.1211 - Channel use policy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Channel use policy. 95.1211 Section 95.1211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Medical Device Radiocommunication Service (MedRadio) § 95.1211 Channel use policy. (a)...

  17. 47 CFR 95.1211 - Channel use policy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Channel use policy. 95.1211 Section 95.1211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Medical Device Radiocommunication Service (MedRadio) § 95.1211 Channel use policy. Link to...

  18. 47 CFR 95.1211 - Channel use policy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Channel use policy. 95.1211 Section 95.1211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Medical Device Radiocommunication Service (MedRadio) § 95.1211 Channel use policy. (a)...

  19. 47 CFR 95.1211 - Channel use policy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Channel use policy. 95.1211 Section 95.1211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Medical Device Radiocommunication Service (MedRadio) § 95.1211 Channel use policy. (a)...

  20. 47 CFR 95.1309 - Channel use policy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Channel use policy. 95.1309 Section 95.1309 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Multi-Use Radio Service (MURS) General Provisions § 95.1309 Channel use policy. (a) The...

  1. 47 CFR 95.1211 - Channel use policy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Channel use policy. 95.1211 Section 95.1211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Medical Device Radiocommunication Service (MedRadio) § 95.1211 Channel use policy. (a)...

  2. 47 CFR 95.1011 - Channel use policy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Channel use policy. 95.1011 Section 95.1011 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Low Power Radio Service (LPRS) General Provisions § 95.1011 Channel use policy. (a) The...

  3. Channel nut tool

    DOEpatents

    Olson, Marvin

    2016-01-12

    A method, system, and apparatus for installing channel nuts includes a shank, a handle formed on a first end of a shank, and an end piece with a threaded shaft configured to receive a channel nut formed on the second end of the shaft. The tool can be used to insert or remove a channel nut in a channel framing system and then removed from the channel nut.

  4. Correlation Between Channel Profile and Plan View Drainage Network Architecture

    NASA Astrophysics Data System (ADS)

    Shelef, E.; Hilley, G. E.

    2011-12-01

    This research explores the relationship between the plan-view network and profile geometry of channels using high-resolution digital topography and numerical models. In particular, we study the relations between plan-view morphometrics of the channel network and the mechanics of land-shaping processes as reflected by channel profile concavity. This analysis addresses one of the long-standing questions in geomorphology relating to the mechanistic significance of various plan-view channel network geometry measures. Statistically based studies suggest that Hortonian measures of channel network architecture (e.g. bifurcation ratio, area ratio, and length ratio) describe virtually all possible network geometries, and hence are not diagnostic when evaluating the origins of the geometry of a particular network. Our analyses of high resolution DEMs that capture different channel profile concavities (i.e debris flow vs. fluvial flows), as well as the topography of landscapes produced by process-based numerical models affirms this conclusion and indicates that Hortonian measures, as well as Hack exponent, are insensitive to channel concavity. In contrast, channel frequency (number of channel segments per area) appears to provide a measure that is sensitive to channel concavity. As such, channel frequency appears to discern between landscapes dominated by different land-shaping processes that produce different channel profile concavities. In the context of headword growing networks, the observed relations between concavity and channel frequency can be modeled through the coupled effect of concavity and surface roughness on the competition between headword growing channels. Our results suggest that the plan-view geometry of channel networks does not simply arise from random deflection of channels that once joined, cannot separate, but rather reflects the underlying processes that incise through rock and transport mass through the channel network

  5. Comparison of mega-flood features of the Channeled Scabland and Martian outflow channels using DEMs

    NASA Astrophysics Data System (ADS)

    Okano, Miki; Oguchi, Takashi

    2014-05-01

    Although current Martian surfaces are too cold and dry to hold liquid water, fluvial features such as valley networks and outflow channels have been observed on the surfaces. The analyses of the fluvial features on Mars are useful for examining past climatic conditions. Outflow channels are the characteristic large flood features on Mars and similar to some large terrestrial flood features such as those in the Channeled Scabland in east-central Washington, USA. The channeled scabland was formed by the Pleistocene Missoula Flood derived from the margins of the Cordilleran Ice Sheet, Glacial Lake Missoula. Thus the Channeled Scabland is useful for a comparison with Martian flood features and examining the paleoenvironment on Mars. However the effect of the Missoula Flood on the formation of the Channeled Scabland has some unresolved questions. Therefore, in this study we analyze the topography of the Channeled Scabland and the area of Glacial Lake Missoula using the ASTER Global Digital Elevation Model (ASTER GDEM) and The National Elevation Dataset (NED). We compare the topography of the Channeled Scabland with that of neighboring areas that has been free of megafloods., Topography in the area of Glacial Lake Missoula is also compared with neighboring areas without glacial lakes. We analyze the frequency distribution and statistical parameters of geomorphometric properties, e.g. slope angle, slope aspect, curvature, and drainage density of each region. We then compare the results with those for Martian outflow channels. The results show that average slope angle increases from the Channeled Scablands to non-megafloods areas, from areas without glacial lakes to the area of Glacial Lake Missoula, and from Martian flood areas to the Channeled Scabland. The same relation holds true for standard deviation except that the standard deviation of the Channeled Scabland is larger when compared to non-megafloods areas, reflecting the generally flat but locally steep topography

  6. An all digital low data rate communication system

    NASA Technical Reports Server (NTRS)

    Chen, C.; Fan, M.

    1973-01-01

    The advent of digital hardwares has made it feasible to implement many communication system components digitally. With the exception of frequency down conversion, the proposed low data rate communication system uses digital hardwares completely. Although the system is designed primarily for deep space communications with large frequency uncertainty and low signal-to-noise ratio, it is also suitable for other low data rate applications with time-shared operation among a number of channels. Emphasis is placed on the fast Fourier transform receiver and the automatic frequency control via digital filtering. The speed available from the digital system allows sophisticated signal processing to reduce frequency uncertainty and to increase the signal-to-noise ratio. The practical limitations of the system such as the finite register length are examined. It is concluded that the proposed all-digital system is not only technically feasible but also has potential cost reduction over the existing receiving systems.

  7. Perceptual-components architecture for digital video

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.

    1990-01-01

    A perceptual-components architecture for digital video partitions the image stream into signal components in a manner analogous to that used in the human visual system. These components consist of achromatic and opponent color channels, divided into static and motion channels, further divided into bands of particular spatial frequency and orientation. Bits are allocated to an individual band in accord with visual sensitivity to that band and in accord with the properties of visual masking. This architecture is argued to have desirable features such as efficiency, error tolerance, scalability, device independence, and extensibility.

  8. Safety Systems

    ERIC Educational Resources Information Center

    Halligan, Tom

    2009-01-01

    Colleges across the country are rising to the task by implementing safety programs, response strategies, and technologies intended to create a secure environment for teachers and students. Whether it is preparing and responding to a natural disaster, health emergency, or act of violence, more schools are making campus safety a top priority. At…

  9. Solidifying Safety

    NASA Technical Reports Server (NTRS)

    Covault, Craig

    2003-01-01

    Contents include the following: 1. Solidifying Safety: NASA s new safety organization spools up, as the 1SS program grapples with long-term risk. 2. Earth to Orbit O'Keefe telling skeptical lawmakers Orbital Space Plan (OSP) will cover exploration vision. China's rapid pace.

  10. Safety First

    ERIC Educational Resources Information Center

    Taft, Darryl

    2011-01-01

    Ned Miller does not take security lightly. As director of campus safety and emergency management at the Des Moines Area Community College (DMACC), any threat requires serious consideration. As community college administrators adopt a more proactive approach to campus safety, many institutions are experimenting with emerging technologies, including…

  11. 47 CFR 22.602 - Transition of the 2110-2130 and 2160-2180 MHz channels to emerging technologies.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... relocation, such as system-wide relocations and analog-to-digital conversions, versus other types of premiums... provide the PARS licensee with an equivalent number of 4 kHz voice channels. If digital facilities are being replaced with digital, the ET licensee must provide the PARS licensee with equivalent data...

  12. 47 CFR 22.602 - Transition of the 2110-2130 and 2160-2180 MHz channels to emerging technologies.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... relocation, such as system-wide relocations and analog-to-digital conversions, versus other types of premiums... provide the PARS licensee with an equivalent number of 4 kHz voice channels. If digital facilities are being replaced with digital, the ET licensee must provide the PARS licensee with equivalent data...

  13. 47 CFR 22.602 - Transition of the 2110-2130 and 2160-2180 MHz channels to emerging technologies.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... relocation, such as system-wide relocations and analog-to-digital conversions, versus other types of premiums... provide the PARS licensee with an equivalent number of 4 kHz voice channels. If digital facilities are being replaced with digital, the ET licensee must provide the PARS licensee with equivalent data...

  14. 47 CFR 22.602 - Transition of the 2110-2130 and 2160-2180 MHz channels to emerging technologies.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... relocation, such as system-wide relocations and analog-to-digital conversions, versus other types of premiums... provide the PARS licensee with an equivalent number of 4 kHz voice channels. If digital facilities are being replaced with digital, the ET licensee must provide the PARS licensee with equivalent data...

  15. 47 CFR 22.602 - Transition of the 2110-2130 and 2160-2180 MHz channels to emerging technologies.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... relocation, such as system-wide relocations and analog-to-digital conversions, versus other types of premiums... provide the PARS licensee with an equivalent number of 4 kHz voice channels. If digital facilities are being replaced with digital, the ET licensee must provide the PARS licensee with equivalent data...

  16. Digital image processing.

    PubMed

    Seeram, Euclid

    2004-01-01

    Digital image processing is now commonplace in radiology, nuclear medicine and sonography. This article outlines underlying principles and concepts of digital image processing. After completing this article, readers should be able to: List the limitations of film-based imaging. Identify major components of a digital imaging system. Describe the history and application areas of digital image processing. Discuss image representation and the fundamentals of digital image processing. Outline digital image processing techniques and processing operations used in selected imaging modalities. Explain the basic concepts and visualization tools used in 3-D and virtual reality imaging. Recognize medical imaging informatics as a new area of specialization for radiologic technologists. PMID:15352557

  17. 75 FR 6215 - Houston/Galveston Navigation Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... SECURITY Coast Guard Houston/Galveston Navigation Safety Advisory Committee AGENCY: Coast Guard, DHS. ACTION: Notice of meetings. SUMMARY: The Houston/Galveston Navigation Safety Advisory Committee... improvements, aids to navigation, area projects impacting safety on the Houston Ship Channel, and various...

  18. 75 FR 23793 - Houston/Galveston Navigation Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... SECURITY Coast Guard Houston/Galveston Navigation Safety Advisory Committee AGENCY: Coast Guard, DHS. ACTION: Notice of meeting. SUMMARY: The Houston/Galveston Navigation Safety Advisory Committee... improvements, aids to navigation, area projects impacting safety on the Houston Ship Channel, and...

  19. Channel erosion in a rapidly urbanizing region of Tijuana, Mexico: Enlargement downstream of channel hardpoints

    NASA Astrophysics Data System (ADS)

    Taniguchi, Kristine; Biggs, Trent; Langendoen, Eddy; Castillo, Carlos; Gudiño, Napoleon; Yuan, Yongping; Liden, Douglas

    2016-04-01

    Urban-induced erosion in Tijuana, Mexico, has led to excessive sediment deposition in the Tijuana Estuary in the United States. Urban areas in developing countries, in contrast to developed countries, are characterized by much lower proportions of vegetation and impervious surfaces due to limited access to urban services such as road paving and landscaping, and larger proportions of exposed soils. In developing countries, traditional watershed scale variables such as impervious surfaces may not be good predictors of channel enlargement. In this research, we surveyed the stream channel network of an erodible tributary of the Tijuana River Watershed, Los Laureles Canyon, at 125 locations, including repeat surveys from 2008. Structure from Motion (SfM) and 3D photo-reconstruction techniques were used to create digital terrain models of stream reaches upstream and downstream of channel hardpoints. Channels are unstable downstream of hardpoints, with incision up to 2 meters and widening up to 12 meters. Coordinated channelization is essential to avoid piece-meal approaches that lead to channel degradation. Watershed impervious area is not a good predictor of channel erosion due to the overriding importance of hardpoints and likely to the high sediment supply from the unpaved roads which prevents channel erosion throughout the stream network.

  20. The Earliest Ion Channels

    NASA Astrophysics Data System (ADS)

    Pohorille, A.; Wilson, M. A.; Wei, C.

    2009-12-01

    Supplying protocells with ions required assistance from channels spanning their membrane walls. The earliest channels were most likely short proteins that formed transmembrane helical bundles surrounding a water-filled pore. These simple aggregates were capable of transporting ions with efficiencies comparable to those of complex, contemporary ion channels. Channels with wide pores exhibited little ion selectivity but also imposed only modest constraints on amino acid sequences of channel-forming proteins. Channels with small pores could have been selective but also might have required a more precisely defined sequence of amino acids. In contrast to modern channels, their protocellular ancestors had only limited capabilities to regulate ion flux. It is postulated that subsequent evolution of ion channels progressed primarily to acquire precise regulation, and not high efficiency or selectivity. It is further proposed that channels and the surrounding membranes co-evolved.

  1. Microfluidic channel fabrication method

    DOEpatents

    Arnold, Don W.; Schoeniger, Joseph S.; Cardinale, Gregory F.

    2001-01-01

    A new channel structure for microfluidic systems and process for fabricating this structure. In contrast to the conventional practice of fabricating fluid channels as trenches or grooves in a substrate, fluid channels are fabricated as thin walled raised structures on a substrate. Microfluidic devices produced in accordance with the invention are a hybrid assembly generally consisting of three layers: 1) a substrate that can or cannot be an electrical insulator; 2) a middle layer, that is an electrically conducting material and preferably silicon, forms the channel walls whose height defines the channel height, joined to and extending from the substrate; and 3) a top layer, joined to the top of the channels, that forms a cover for the channels. The channels can be defined by photolithographic techniques and are produced by etching away the material around the channel walls.

  2. Synchronization techniques for all digital 16-ary QAM receivers operating over land mobile satellite links

    NASA Technical Reports Server (NTRS)

    Fines, P.; Aghvami, A. H.

    1990-01-01

    The performance of a low bit rate (64 Kb/s) all digital 16-ary Differentially Encoded Quadrature Amplitude Modulation (16-DEQAM) demodulator operating over a mobile satellite channel, is considered. The synchronization and detection techniques employed to overcome the Rician channel impairments, are described. The acquisition and steady state performance of this modem, are evaluated by computer simulation over AWGN and RICIAN channels. The results verify the suitability of the 16-DEQAM transmission over slowly faded and/or mildly faded channels.

  3. Gramicidin Channels: Versatile Tools

    NASA Astrophysics Data System (ADS)

    Andersen, Olaf S.; Koeppe, Roger E., II; Roux, Benoît

    Gramicidin channels are miniproteins in which two tryptophan-rich subunits associate by means of transbilayer dimerization to form the conducting channels. That is, in contrast to other ion channels, gramicidin channels do not open and close; they appear and disappear. Each subunit in the bilayer-spanning channel is tied to the bilayer/solution interface through hydrogen bonds that involve the indole NH groups as donors andwater or the phospholipid backbone as acceptors. The channel's permeability characteristics are well-defined: gramicidin channels are selective for monovalent cations, with no measurable permeability to anions or polyvalent cations; ions and water move through a pore whose wall is formed by the peptide backbone; and the single-channel conductance and cation selectivity vary when the amino acid sequence is varied, even though the permeating ions make no contact with the amino acid side chains. Given the plethora of available experimental information—for not only the wild-type channels but also for channels formed by amino acid-substituted gramicidin analogues—gramicidin channels continue to provide important insights into the microphysics of ion permeation through bilayer-spanning channels. For similar reasons, gramicidin channels constitute a system of choice for evaluating computational strategies for obtaining mechanistic insights into ion permeation through the more complex channels formed by integral membrane proteins.

  4. Linear signal-compensated amplifier for reactor power measuring channels

    SciTech Connect

    Khaleeq, M. Tahir; Atique-ur-Rahman,; Ahmed, Eijaz

    2006-07-15

    A linear amplifier with automatic signal compensation has been developed for nuclear channels. The amplifier controls its sensitivity automatically according to the reference input within the desired settings and has automatic signal compensation capability for use in the nuclear channels. The amplifier will be used in the existing safety channel of Pakistan Research Reactor-1, where the system has an independent sensitivity control unit for manual compensation of xenon effect. The new amplifier will improve the safety of the system. The amplifier is tested and the results found are in very good agreement with the designed specifications. This article presents design and construction of the amplifier and test results.

  5. Linear signal-compensated amplifier for reactor power measuring channels

    NASA Astrophysics Data System (ADS)

    Khaleeq, M. Tahir; Atique-ur-Rahman, Ahmed, Eijaz

    2006-07-01

    A linear amplifier with automatic signal compensation has been developed for nuclear channels. The amplifier controls its sensitivity automatically according to the reference input within the desired settings and has automatic signal compensation capability for use in the nuclear channels. The amplifier will be used in the existing safety channel of Pakistan Research Reactor-1, where the system has an independent sensitivity control unit for manual compensation of xenon effect. The new amplifier will improve the safety of the system. The amplifier is tested and the results found are in very good agreement with the designed specifications. This article presents design and construction of the amplifier and test results.

  6. Receiver techniques for microwave digital radio

    NASA Astrophysics Data System (ADS)

    Chamberlain, J. K.; Clayton, F. M.; Sari, H.; Vandamme, P.

    1986-11-01

    Adaptive receiver design features and operating techniques are described which have been devised to offset the deleterious effects of multipath fading in digital radio systems. Frequency-domain and time-domain circuitry are discussed for equalizing channel distortion, and attention is also given to carrier and symbol synchronization subsystems. Height and frequency diversity are summarized for safeguarding signals from destruction by propagation effects and methods for adaptive cancellation of cross-polarized interference are described.

  7. User`s manual for the CDC-1 digitizer controller

    SciTech Connect

    Ferron, J.R.

    1994-09-01

    A detailed description of how to use the CDC-1 digitizer controller is given. The CDC-1 is used with the CAMAC format digitizer models in the TRAQ series (manufactured by DSP Technology Inc.), the DAD-1 data acquisition daughter board, and the Intel i860-based SuperCard-2 (manufactured, by CSP Inc.) to form a high speed data acquisition and real time analysis system. Data can be transferred to the memory on the SuperCard-2 at a rate as high as 40 million 14-bit samples per second. Depending on the model of TRAQ digitizer in use, digitizing rates up to 3.33 MHz are supported (with eight data channels), or, for instance, at a sample rate of 100 kHz, 384 data channels can be acquired.

  8. A digital audio/video interleaving system. [for Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Richards, R. W.

    1978-01-01

    A method of interleaving an audio signal with its associated video signal for simultaneous transmission or recording, and the subsequent separation of the two signals, is described. Comparisons are made between the new audio signal interleaving system and the Skylab Pam audio/video interleaving system, pointing out improvements gained by using the digital audio/video interleaving system. It was found that the digital technique is the simplest, most effective and most reliable method for interleaving audio and/or other types of data into the video signal for the Shuttle Orbiter application. Details of the design of a multiplexer capable of accommodating two basic data channels, each consisting of a single 31.5-kb/s digital bit stream are given. An adaptive slope delta modulation system is introduced to digitize audio signals, producing a high immunity of work intelligibility to channel errors, primarily due to the robust nature of the delta-modulation algorithm.

  9. The new digital data acquisition system for Gammasphere

    NASA Astrophysics Data System (ADS)

    Carpenter, M. P.; Albers, M.; Anderson, J. T.; Ayangeakaa, A.; David, H. M.; Hoffman, C. R.; Janssens, R. V. F.; Lauritsen, T.; Madden, T.; Oberling, M.; Seweryniak, D.; Wilt, P.; Zhu, S.

    2015-10-01

    A new digital-based data acquisition system (DAQ) for Gammasphere has been developed. This system leverages the electronics designed for the GRETINA collaboration. At the center of this development are the GRETINA 10-channel digitizer modules which handle the Ge preamp signals at a 100MHz rate, and master trigger and router modules which allow triggers to be constructed from information obtained from the digitizer channels. The new DAQ increases event throughput significantly over the existing system while addressing multiple repair and maintenance issues. New hardware and firmware to integrate the DAQ with Gammasphere and its suite of ancillary detectors has been developed allowing for a seamless changeover from the analog DAQ to the new digital system. An overview of the system and illustrative results from several recent experiments will be presented. This material is based on work supported by the DOE, Office of Science, Office of Nuclear Physics under Contract No. DE-AC02-06CH11357.

  10. Software safety

    NASA Technical Reports Server (NTRS)

    Leveson, Nancy

    1987-01-01

    Software safety and its relationship to other qualities are discussed. It is shown that standard reliability and fault tolerance techniques will not solve the safety problem for the present. A new attitude requires: looking at what you do NOT want software to do along with what you want it to do; and assuming things will go wrong. New procedures and changes to entire software development process are necessary: special software safety analysis techniques are needed; and design techniques, especially eliminating complexity, can be very helpful.

  11. The Tenth Annual Ion Channel Retreat, Vancouver, Canada, June 25–27, 2012

    PubMed Central

    Kimlicka, Lynn; Liang, Sophia; Brugger, Saranna; Liang, Dong

    2013-01-01

    Abstract Ten years after Aurora Biomed (Vancouver, British Columbia, Canada) hosted the inaugural Ion Channel Retreat, this event is recognized as a leading conference for ion channel researchers. Held annually in Vancouver, this meeting consistently provides an outlet for researchers to share their findings while learning about new concepts, methods, and technologies. Researchers use this forum to discuss and debate a spectrum of topics from ion channel research and technology to drug discovery and safety. The Retreat covered key subjects in the ion channel industry, including ion channels as disease targets, transient receptor protein channels as pain and disease targets, ion channels as pain targets, ion channel structure and function, ion channel screening technologies, cardiac safety and toxicology, and cardiac function and pharmacology. PMID:23679851

  12. Fading channel simulator

    SciTech Connect

    Argo, P.E.; Fitzgerald, T.J.

    1991-12-31

    This invention relates to high frequency (HF) radio signal propagation through fading channels and, more particularly, to simulation of fading channels in order to characterize HF radio system performance in transmitting and receiving signals through such fading channels. Fading channel effects on a transmitted communication signal are simulated with both frequency and time variations using a channel scattering function to affect the transmitted signal. A conventional channel scattering function is converted to a series of channel realizations by multiplying the square root of the channel scattering function by a complex number of which the real and imaginary parts are each independent variables. The two-dimensional inverse-FFT of this complex-valued channel realization yields a matrix of channel coefficients that provide a complete frequency-time description of the channel. The transmitted radio signal is segmented to provide a series of transmitted signal and each segment is subject to FFT to generate a series of signal coefficient matrices. The channel coefficient matrices and signal coefficient matrices are then multiplied and subjected to inverse-FFT to output a signal representing the received affected radio signal. A variety of channel scattering functions can be used to characterize the response of a transmitter-receiver system to such atmospheric effects.

  13. Testing of Error-Correcting Sparse Permutation Channel Codes

    NASA Technical Reports Server (NTRS)

    Shcheglov, Kirill, V.; Orlov, Sergei S.

    2008-01-01

    A computer program performs Monte Carlo direct numerical simulations for testing sparse permutation channel codes, which offer strong error-correction capabilities at high code rates and are considered especially suitable for storage of digital data in holographic and volume memories. A word in a code of this type is characterized by, among other things, a sparseness parameter (M) and a fixed number (K) of 1 or "on" bits in a channel block length of N.

  14. Digital subtraction laryngography

    SciTech Connect

    Brown, B.W.; Enzmann, D.R.; Hopp, M.L.; Castellino, R.A.

    1983-06-01

    Digital subtraction laryngography was used to evaluate laryngeal function in 8 patients: 4 with normal larynxes and 4 with laryngeal disease. Subtracted digital images provided a dynamic display of the extent and symmetry of vocal cord excursions and pyriform sinus inflation, and the vocal cord resting position was also clearly depicted. The technical details of digital subtraction laryngography and its application are described.

  15. Bridging the Digital Divide

    ERIC Educational Resources Information Center

    Clarke, Alan; Milner, Helen; Killer, Terry; Dixon, Genny

    2008-01-01

    As the Government publishes its action plan for consultation on digital inclusion, the authors consider some of the challenges and opportunities for the delivery of digital inclusion. Clarke argues that digital inclusion requires more than access to technology or the skills to use it effectively, it demands information and media literacy. Milner…

  16. Digital Ink and Notetaking

    ERIC Educational Resources Information Center

    Colwell, Kenneth E.

    2004-01-01

    Tablet PCs and graphics tablets employ digital ink technology. In this paper the author introduces the reader to digital ink technology with the aim of promoting its use in various instructional or training settings, with the goal of improving instructor-learner dialogue and student learning. The potential of digital ink for improved instructional…

  17. Reconceptualising Critical Digital Literacy

    ERIC Educational Resources Information Center

    Pangrazio, Luciana

    2016-01-01

    While it has proved a useful concept during the past 20 years, the notion of "critical digital literacy" requires rethinking in light of the fast-changing nature of young people's digital practices. This paper contrasts long-established notions of "critical digital literacy" (based primarily around the critical consumption of…

  18. Digital Literacy. Research Brief

    ERIC Educational Resources Information Center

    Williamson, Ronald

    2011-01-01

    21st Century students need a complex set of skills to be successful in a digital environment. Digital literacy, similar to traditional definitions of literacy, is a set of skills students use to locate, organize, understand, evaluate and create information. The difference is that it occurs in an environment where a growing set of digital tools…

  19. Digital Language Death

    PubMed Central

    Kornai, András

    2013-01-01

    Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide. PMID:24167559

  20. Mass Digitization of Books

    ERIC Educational Resources Information Center

    Coyle, Karen

    2006-01-01

    Mass digitization of the bound volumes that we generally call "books" has begun, and, thanks to the interest in Google and all that it does, it is getting widespread media attention. The Open Content Alliance (OCA), a library initiative formed after Google announced its library book digitization project, has brought library digitization projects…

  1. NEXUS: Digitizing Higher Education.

    ERIC Educational Resources Information Center

    Kirk, Camille

    2000-01-01

    Discussion of digital technology in the context of higher education planning considers how these technologies change teaching; the digital divide; the costs of information technology; hard wiring the campus; material consequences of information technology; digitally enabled crimes and misdemeanors; and libraries and scholarly publishing. Concludes…

  2. Digital language death.

    PubMed

    Kornai, András

    2013-01-01

    Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide. PMID:24167559

  3. Safety Tips.

    ERIC Educational Resources Information Center

    Nagel, Miriam C., Ed.

    1984-01-01

    Outlines a cooperative effort in Iowa to eliminate dangerous or unwanted chemicals from school science storerooms. Also reviews the Council of State Science Supervisor's safety program and discusses how to prevent cuts and punctures from jagged glass tubing. (JN)

  4. Food Safety

    MedlinePlus

    ... are four basic steps to food safety at home: Clean - always wash your fruits and vegetables, hands, counters, and cooking utensils. Separate - keep raw foods to themselves. Germs can spread from one food ...

  5. A 64-channel ultra-low power system-on-chip for local field and action potentials recording

    NASA Astrophysics Data System (ADS)

    Rodríguez-Pérez, Alberto; Delgado-Restituto, Manuel; Darie, Angela; Soto-Sánchez, Cristina; Fernández-Jover, Eduardo; Rodríguez-Vázquez, Ángel

    2015-06-01

    This paper reports an integrated 64-channel neural recording sensor. Neural signals are acquired, filtered, digitized and compressed in the channels. Additionally, each channel implements an auto-calibration mechanism which configures the transfer characteristics of the recording site. The system has two transmission modes; in one case the information captured by the channels is sent as uncompressed raw data; in the other, feature vectors extracted from the detected neural spikes are released. Data streams coming from the channels are serialized by an embedded digital processor. Experimental results, including in vivo measurements, show that the power consumption of the complete system is lower than 330μW.

  6. Multi-channel time-reversal receivers for multi and 1-bit implementations

    DOEpatents

    Candy, James V.; Chambers, David H.; Guidry, Brian L.; Poggio, Andrew J.; Robbins, Christopher L.

    2008-12-09

    A communication system for transmitting a signal through a channel medium comprising digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. In one embodiment a transmitter is adapted to transmit the signal, a multiplicity of receivers are adapted to receive the signal, a digitizer digitizes the signal, and a time-reversal signal processor is adapted to time-reverse the digitized signal. An embodiment of the present invention includes multi bit implementations. Another embodiment of the present invention includes 1-bit implementations. Another embodiment of the present invention includes a multiplicity of receivers used in the step of transmitting the signal through the channel medium.

  7. Evaluating Small Scintillating Cells for Digital Hadron Calorimeters

    SciTech Connect

    Francis, Kurt

    2004-01-01

    This thesis discusses the use of scintillator cells with digital electronics as a basis for a digital hadron calorimeter. The detection of a minimum ionizing particle (MIP), analysis of crosstalk, and determination of light yield for the array of scintillating cells are described. The cells were found to have a light yield (in terms of single photoelectrons per MIP) of 7 to 13. Crosstalk due to transfer of light between adjacent cells or photomultiplier tube channels can reach 45%. Rejection versus efficiency studies show that single-channel thresholds can be set that reject noise while accepting MIP signals.

  8. Calcium channel blocker overdose

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  9. Digital Calibration of TR Modules for Real-time Digital Beamforming SweepSAR Architectures

    NASA Technical Reports Server (NTRS)

    Hoffman, James Patrick; Perkovic, Dragana; Shaffer, Scott; Veilleux, Louise; Peral, Eva

    2011-01-01

    Real-time digital beamforming, combined with lightweight, large aperture reflectors, enable SweepSAR architectures such as that of the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI). These new instrument concepts require new methods for calibrating the multiple channels, which must be combined on-board, in real-time. The calibration of current state-of-the-art Electronically Steered Arrays typically involves pre-flight TR (Transmit/Receive) module characterization over temperature, and in-flight correction based on temperature, which ignores the effects of element aging and drifts unrelated to temperature. We are developing new methods for digitally calibrating digital beamforming arrays to reduce development time, risk and cost of precision calibrated TR modules for array architectures by accurately tracking modules' characteristics through closed-loop Digital Calibration, thus tracking systematic changes regardless of temperature. The benefit of this effort is that it would enable a new class of lightweight radar architecture, Digital Beamforming with SweepSAR, providing significantly larger swath coverage than conventional SAR architectures for solid earth and biomass remote sensing, while reducing mission mass and cost. This new instrument concept requires new methods for calibrating the multiple channels, which must be combined on-board, in real-time.

  10. 622-Mbps Orthogonal Frequency Division Multiplexing (OFDM) Digital Modem Implemented

    NASA Technical Reports Server (NTRS)

    Kifle, Muli; Bizon, Thomas P.; Nguyen, Nam T.; Tran, Quang K.; Mortensen, Dale J.

    2002-01-01

    Future generation space communications systems feature significantly higher data rates and relatively smaller frequency spectrum allocations than systems currently deployed. This requires the application of bandwidth- and power-efficient signal transmission techniques. There are a number of approaches to implementing such techniques, including analog, digital, mixed-signal, single-channel, or multichannel systems. In general, the digital implementations offer more advantages; however, a fully digital implementation is very difficult because of the very high clock speeds required. Multichannel techniques are used to reduce the sampling rate. One such technique, multicarrier modulation, divides the data into a number of low-rate channels that are stacked in frequency. Orthogonal frequency division multiplexing (OFDM), a form of multicarrier modulation, is being proposed for numerous systems, including mobile wireless and digital subscriber link communication systems. In response to this challenge, NASA Glenn Research Center's Communication Technology Division has developed an OFDM digital modem (modulator and demodulator) with an aggregate information throughput of 622 Mbps. The basic OFDM waveform is constructed by dividing an incoming data stream into four channels, each using either 16- ary quadrature amplitude modulation (16-QAM) or 8-phase shift keying (8-PSK). An efficient implementation for an OFDM architecture is being achieved using the combination of a discrete Fourier transform (DFT) at the transmitter to digitally stack the individual carriers, inverse DFT at the receiver to perform the frequency translations, and a polyphase filter to facilitate the pulse shaping.

  11. Digital Front End for Wide-Band VLBI Science Receiver

    NASA Technical Reports Server (NTRS)

    Jongeling, Andre; Sigman, Elliott; Navarro, Robert; Goodhart, Charles; Rogstad, Steve; Chandra, Kumar; Finley, Sue; Trinh, Joseph; Soriano, Melissa; White, Les; Proctor, Robert; Rayhrer, Benno

    2006-01-01

    An upgrade to the very-long-baseline-interferometry (VLBI) science receiver (VSR) a radio receiver used in NASA's Deep Space Network (DSN) is currently being implemented. The current VSR samples standard DSN intermediate- frequency (IF) signals at 256 MHz and after digital down-conversion records data from up to four 16-MHz baseband channels. Currently, IF signals are limited to the 265-to-375-MHz range, and recording rates are limited to less than 80 Mbps. The new digital front end, denoted the Wideband VSR, provides improvements to enable the receiver to process wider bandwidth signals and accommodate more data channels for recording. The Wideband VSR utilizes state-of-the-art commercial analog-to-digital converter and field-programmable gate array (FPGA) integrated circuits, and fiber-optic connections in a custom architecture. It accepts IF signals from 100 to 600 MHz, sampling the signal at 1.28 GHz. The sample data are sent to a digital processing module, using a fiber-optic link for isolation. The digital processing module includes boards designed around an Advanced Telecom Computing Architecture (ATCA) industry-standard backplane. Digital signal processing implemented in FPGAs down-convert the data signals in up to 16 baseband channels with programmable bandwidths from 1 kHz to 16 MHz. Baseband samples are transmitted to a computer via multiple Ethernet connections allowing recording to disk at rates of up to 1 Gbps.

  12. Optimal channels for channelized quadratic estimators.

    PubMed

    Kupinski, Meredith K; Clarkson, Eric

    2016-06-01

    We present a new method for computing optimized channels for estimation tasks that is feasible for high-dimensional image data. Maximum-likelihood (ML) parameter estimates are challenging to compute from high-dimensional likelihoods. The dimensionality reduction from M measurements to L channels is a critical advantage of channelized quadratic estimators (CQEs), since estimating likelihood moments from channelized data requires smaller sample sizes and inverting a smaller covariance matrix is easier. The channelized likelihood is then used to form ML estimates of the parameter(s). In this work we choose an imaging example in which the second-order statistics of the image data depend upon the parameter of interest: the correlation length. Correlation lengths are used to approximate background textures in many imaging applications, and in these cases an estimate of the correlation length is useful for pre-whitening. In a simulation study we compare the estimation performance, as measured by the root-mean-squared error (RMSE), of correlation length estimates from CQE and power spectral density (PSD) distribution fitting. To abide by the assumptions of the PSD method we simulate an ergodic, isotropic, stationary, and zero-mean random process. These assumptions are not part of the CQE formalism. The CQE method assumes a Gaussian channelized likelihood that can be a valid for non-Gaussian image data, since the channel outputs are formed from weighted sums of the image elements. We have shown that, for three or more channels, the RMSE of CQE estimates of correlation length is lower than conventional PSD estimates. We also show that computing CQE by using a standard nonlinear optimization method produces channels that yield RMSE within 2% of the analytic optimum. CQE estimates of anisotropic correlation length estimation are reported to demonstrate this technique on a two-parameter estimation problem. PMID:27409452

  13. Channel catfish pond fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The most successful aquaculture enterprise in the U.S. is channel catfish Ictalurus punctatus production. In the U.S., 257 million kg of channel catfish were sold in 2007 at a value of $455 million. Large-scale commercial channel catfish culture began in the late 1950s and expanded rapidly from 1978...

  14. Digital Mammography and Digital Breast Tomosynthesis.

    PubMed

    Moseley, Tanya W

    2016-06-01

    Breast imaging technology has advanced significantly from the 1930s until the present. American women have a 1 in 8 chance of developing breast cancer. Mammography has been proven in multiple clinical trials to reduce breast cancer mortality. Although a mainstay of breast imaging and improved from film-screen mammography, digital mammography is not a perfect examination. Overlapping obscuring breast tissue limits mammographic interpretation. Breast digital tomosynthesis reduces and/or eliminates overlapping obscuring breast tissue. Although there are some disadvantages with digital breast tomosynthesis, this relatively lost-cost technology may be used effectively in the screening and diagnostic settings. PMID:27101241

  15. An algorithm for treating flat areas and depressions in digital elevation models using linear interpolation

    EPA Science Inventory

    Digital elevation model (DEM) data are essential to hydrological applications and have been widely used to calculate a variety of useful topographic characteristics, e.g., slope, flow direction, flow accumulation area, stream channel network, topographic index, and others. Excep...

  16. System safety education focused on flight safety

    NASA Technical Reports Server (NTRS)

    Holt, E.

    1971-01-01

    The measures necessary for achieving higher levels of system safety are analyzed with an eye toward maintaining the combat capability of the Air Force. Several education courses were provided for personnel involved in safety management. Data include: (1) Flight Safety Officer Course, (2) Advanced Safety Program Management, (3) Fundamentals of System Safety, and (4) Quantitative Methods of Safety Analysis.

  17. Overview of safety pharmacology.

    PubMed

    Goineau, Sonia; Lemaire, Martine; Froget, Guillaume

    2013-01-01

    Safety pharmacology entails the assessment of the potential risks of novel pharmaceuticals for human use. As detailed in the ICH S7A guidelines, safety pharmacology for drug discovery involves a core battery of studies on three vital systems: central nervous (CNS), cardiovascular (CV), and respiratory. Primary CNS studies are aimed at defining compound effects on general behavior, locomotion, neuromuscular coordination, seizure threshold, and vigilance. The primary CV test battery includes an evaluation of proarrhythmic risk using in vitro tests (hERG channel and Purkinje fiber assays) and in vivo measurements in conscious animals via telemetry. Comprehensive cardiac risk assessment also includes full hemodynamic evaluation in a large, anesthetized animal. Basic respiratory function can be examined in conscious animals using whole-body plethysmography. This allows for an assessment of whether the sensitivity to respiratory-depressant effects can be enhanced by exposure to increased CO2 . Other safety pharmacology topics detailed in this unit are the timing of such studies, ethical and animal welfare issues, and statistical evaluation. PMID:24510755

  18. Digital rights management for digital cinema

    NASA Astrophysics Data System (ADS)

    Kirovski, Darko; Peinado, Marcus; Petitcolas, Fabien A. P.

    2001-12-01

    There is a wide consensus among the feature film production studios that the Internet era brings a new paradigm for film distribution to cinemas worldwide. The benefits of digital cinema to both producers and cinemas are numerous: significantly lower distribution and maintenance costs, immediate access to film libraries, higher presentation quality, and strong potential for developing new business models. Despite these advantages, the studios are still reluctant to jump into the digital age. The main showstopper for digital cinema is the danger of widespread piracy. Piracy already costs Hollywood an estimated two billion dollars annually and digital cinema without proper copyright enforcement could increase this number. In this paper, we present a copyright management system that aims at providing the set of necessary security tools: standard cryptographic primitives and copyright protection mechanisms that enable a reliable and secure feature film delivery system.

  19. Digital Collections, Digital Libraries and the Digitization of Cultural Heritage Information.

    ERIC Educational Resources Information Center

    Lynch, Clifford

    2002-01-01

    Discusses the development of digital collections and digital libraries. Topics include digitization of cultural heritage information; broadband issues; lack of compelling content; training issues; types of materials being digitized; sustainability; digital preservation; infrastructure; digital images; data mining; and future possibilities for…

  20. Integrated source and channel encoded digital communication system design study

    NASA Technical Reports Server (NTRS)

    Huth, G. K.; Udalov, S.

    1974-01-01

    This study investigated the configuration and integration of a wideband communication system with a Ku-band rendezvous radar system. The goal of the study was to provide as much commonality between the two systems as possible. The antenna design was described with the only change being the requirement for dual polarization (linear for the radar system and circular for the communication system).

  1. N Channel JFET Based Digital Logic Gate Structure

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J (Inventor)

    2013-01-01

    An apparatus is provided that includes a first field effect transistor with a source tied to zero volts and a drain tied to voltage drain drain (Vdd) through a first resistor. The apparatus also includes a first node configured to tie a second resistor to a third resistor and connect to an input of a gate of the first field effect transistor in order for the first field effect transistor to receive a signal. The apparatus also includes a second field effect transistor configured as a unity gain buffer having a drain tied to Vdd and an uncommitted source.

  2. 47 CFR 74.786 - Digital channel assignments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... also at the following internet sites: http://wireless.fcc.gov/publicsafety700MHzregional.html, http://wireless.fcc.gov/publicsafety/700MHz/state.html, and http://wireless.fcc.gov/publicsafety/700MHz/interop-contacts.html. (f) Application for new analog low power television or television translator...

  3. Integrated source and channel encoded digital communication system design study

    NASA Technical Reports Server (NTRS)

    Alem, W. K.; Huth, G. K.; Simon, M. K.

    1978-01-01

    The particular Ku-band carrier, PN despreading, and symbol synchronization strategies, which were selected for implementation in the Ku-band transponder aboard the orbiter, were assessed and evaluated from a systems performance viewpoint, verifying that system specifications were met. A study was performed of the design and implementation of tracking techniques which are suitable for incorporation into the Orbiter Ku-band communication system. Emphasis was placed on maximizing tracking accuracy and communication system flexibility while minimizing cost, weight, and system complexity of Orbiter and ground systems hardware. The payload communication study assessed the design and performance of the forward link and return link bent-pipe relay modes for attached and detached payloads. As part of this study, a design for a forward link bent-pipe was proposed which employs a residual carrier but which is tracked by the existing Costas loop.

  4. Integrated source and channel encoded digital communication system design study

    NASA Technical Reports Server (NTRS)

    Udalov, S.; Huth, G. K.

    1977-01-01

    The analysis of the forward link signal structure for the shuttle orbiter Ku-band communication system was carried out, based on the assumptions of a 3.03 Mcps PN code. It is shown that acquisition requirements for the forward link can be met at the acquisition threshold C/N0 sub 0 value of about 60 dB-Hz, which corresponds to a bit error rate (BER) of about 0.001. It is also shown that the tracking threshold for the forward link is at about 57 dB-Hz. The analysis of the bent pipe concept for the orbiter was carried out, along with the comparative analysis of the empirical data. The complexity of the analytical approach warrants further investigation to reconcile the empirical and theoretical results. Techniques for incorporating a text and graphics capability into the forward link data stream are considered and a baseline configuration is described.

  5. Bacterial Ion Channels.

    PubMed

    Compton, Emma L R; Mindell, Joseph A

    2010-09-01

    Bacterial ion channels were known, but only in special cases, such as outer membrane porins in Escherichia coli and bacterial toxins that form pores in their target (bacterial or mammalian) membranes. The exhaustive coverage provided by a decade of bacterial genome sequencing has revealed that ion channels are actually widespread in bacteria, with homologs of a broad range of mammalian channel proteins coded throughout the bacterial and archaeal kingdoms. This review discusses four groups of bacterial channels: porins, mechano-sensitive (MS) channels, channel-forming toxins, and bacterial homologs of mammalian channels. The outer membrane (OM) of gram-negative bacteria blocks access of essential nutrients; to survive, the cell needs to provide a mechanism for nutrients to penetrate the OM. Porin channels provide this access by forming large, nonspecific aqueous pores in the OM that allow ions and vital nutrients to cross it and enter the periplasm. MS channels act as emergency release valves, allowing solutes to rapidly exit the cytoplasm and to dissipate the large osmotic disparity between the internal and external environments. MS channels are remarkable in that they do this by responding to forces exerted by the membrane itself. Some bacteria produce toxic proteins that form pores in trans, attacking and killing other organisms by virtue of their pore formation. The review focuses on those bacterial toxins that kill other bacteria, specifically the class of proteins called colicins. Colicins reveal the dangers of channel formation in the plasma membrane, since they kill their targets with exactly that approach. PMID:26443789

  6. Mechanically Activated Ion Channels.

    PubMed

    Ranade, Sanjeev S; Syeda, Ruhma; Patapoutian, Ardem

    2015-09-23

    Mechanotransduction, the conversion of physical forces into biochemical signals, is essential for various physiological processes such as the conscious sensations of touch and hearing, and the unconscious sensation of blood flow. Mechanically activated (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how mechanical force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels. PMID:26402601

  7. C. elegans TRP channels

    PubMed Central

    Xiao, Rui; Xu, X.Z. Shawn

    2010-01-01

    TRP (transient receptor potential) channels represent a superfamily of cation channels found in all eukaryotes. The C. elegans genome encodes seventeen TRP channels covering all of the seven TRP subfamilies. Genetic analyses in C. elegans have implicated TRP channels in a wide spectrum of behavioral and physiological processes, ranging from sensory transduction (e.g. chemosensation, touch sensation, proprioception and osmosensation) to fertilization, drug dependence, organelle biogenesis, apoptosis, gene expression, and neurotransmitter/hormone release. Many C. elegans TRP channels share similar activation and regulatory mechanisms with their vertebrate counterparts. Studies in C. elegans have also revealed some previously unrecognized functions and regulatory mechanisms of TRP channels. C. elegans represents an excellent genetic model organism for the study of function and regulation of TRP channels in vivo. PMID:21290304

  8. An all digital low data rate communication system

    NASA Technical Reports Server (NTRS)

    Chen, C.-H.; Fan, M.

    1973-01-01

    The advent of digital hardwares has made it feasible to implement many communication system components digitally. With the exception of frequency down conversion, the proposed low data rate communication system uses digital hardware completely. Although the system is designed primarily for deep space communications with large frequency uncertainty and low signal-to-noise ratio, it is also suitable for other low data rate applications with time-shared operation among a number of channels. Emphasis is placed on the fast Fourier transform receiver and the automatic frequency control via digital filtering. The speed available from the digital system allows sophisticated signal processing to reduce frequency uncertainty and to increase the signal-to-noise ratio.

  9. One GHz digitizer for space based laser altimeter

    NASA Technical Reports Server (NTRS)

    Staples, Edward J.

    1991-01-01

    This is the final report for the research and development of the one GHz digitizer for space based laser altimeter. A feasibility model was designed, built, and tested. Only partial testing of essential functions of the digitizer was completed. Hybrid technology was incorporated which allows analog storage (memory) of the digitally sampled data. The actual sampling rate is 62.5 MHz, but executed in 16 parallel channels, to provide an effective sampling rate of one GHz. The average power consumption of the one GHz digitizer is not more than 1.5 Watts. A one GHz oscillator is incorporated for timing purposes. This signal is also made available externally for system timing. A software package was also developed for internal use (controls, commands, etc.) and for data communication with the host computer. The digitizer is equipped with an onboard microprocessor for this purpose.

  10. The sixteen channel CAMAC constant fraction discriminator for APEX

    SciTech Connect

    Maier, M.R. ); Robertson, M. ); Wolfs, F.L.H.; Perera, P.A.A. . Nuclear Structure Research Lab.)

    1991-11-01

    We report on the construction and the performance of a sixteen channel constant fraction discriminator (CFD) for the Atlas Positron Experiment (APEX). We have used an integrated circuit (IC), recently introduced commercially, which contains all the electronic building blocks needed to construct a CFD. We have placed 16 channels of CFD into a CAMAC module. An important feature is the time to charge converter (TQC) that we have included for every CFD channel. Its calibration constant is controlled via CAMAC. The TQC allows the use charge sensitive analog to digital converters (QDC) for timing measurements. Results for CFD walk, resolution and crosstalk as well as for TQC linearity will be presented.

  11. Immunizing digital systems against electromagnetic interference

    NASA Astrophysics Data System (ADS)

    Ewing, P. D.; Korsah, K.; Antonescu, C.

    This paper discusses the development of the technical basis for acceptance criteria applicable to the immunization of digital systems against electromagnetic interference (EMI). The work is sponsored by the US Nuclear Regulatory Commission and stems from the safety-related issues that need to be addressed as a result of the application of digital instrumentation and control systems in nuclear power plants. Designers of digital circuits are incorporating increasingly higher clock frequencies and lower logic level voltages, thereby leading to potentially greater susceptibility of spurious interference being misinterpreted as legitimate logic. Development of the technical basis for acceptance criteria to apply to these digital systems centers around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant's electronic and electromechanical systems. First, good EMC design and installation practices are needed to control the emissions from interference sources and thereby their impact on other nearby circuits and systems. Secondly, a test and evaluation program is needed to outline the EMI tests to be performed, the associated test methods to be followed, and adequate test limits to ensure that the circuit or system under test meets the recommended guidelines. Test and evaluation should be followed by periodic maintenance to assess whether the recommended EMI control practices continue to be adhered to as part of the routine operation of the nuclear power plant. By following these steps, the probability of encountering safety-related instrumentation problems associated with EMI will be greatly reduced.

  12. 78 FR 50457 - Advisory Committee on Reactor Safeguards (ACRS) Meeting of the ACRS Subcommittee on Digital I&C...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... identification of digital system failure modes and use of hazard analysis methods for digital safety systems. The... ACRS meetings were published in the Federal Register on October 18, 2012, (77 FR 64146-64147). Detailed... COMMISSION Advisory Committee on Reactor Safeguards (ACRS) Meeting of the ACRS Subcommittee on Digital...

  13. First Aid and Safety

    MedlinePlus

    ... First-Aid Kit Food Safety for Your Family Gun Safety Halloween Candy Hints Household Safety Checklists Household ... Climbing, and Grabbing Household Safety: Preventing Injuries From Firearms Household Safety: Preventing Injuries in the Crib Household ...

  14. The Digital Fields Board for the FIELDS instrument suite on the Solar Probe Plus mission: Analog and digital signal processing

    NASA Astrophysics Data System (ADS)

    Malaspina, David M.; Ergun, Robert E.; Bolton, Mary; Kien, Mark; Summers, David; Stevens, Ken; Yehle, Alan; Karlsson, Magnus; Hoxie, Vaughn C.; Bale, Stuart D.; Goetz, Keith

    2016-06-01

    The first in situ measurements of electric and magnetic fields in the near-Sun environment (< 0.25 AU from the Sun) will be made by the FIELDS instrument suite on the Solar Probe Plus mission. The Digital Fields Board (DFB) is an electronics board within FIELDS that performs analog and digital signal processing, as well as digitization, for signals between DC and 60 kHz from five voltage sensors and four search coil magnetometer channels. These nine input signals are processed on the DFB into 26 analog data streams. A specialized application-specific integrated circuit performs analog to digital conversion on all 26 analog channels simultaneously. The DFB then processes the digital data using a field programmable gate array (FPGA), generating a variety of data products, including digitally filtered continuous waveforms, high-rate burst capture waveforms, power spectra, cross spectra, band-pass filter data, and several ancillary products. While the data products are optimized for encounter-based mission operations, they are also highly configurable, a key design aspect for a mission of exploration. This paper describes the analog and digital signal processing used to ensure that the DFB produces high-quality science data, using minimal resources, in the challenging near-Sun environment.

  15. Fading channel simulator

    DOEpatents

    Argo, Paul E.; Fitzgerald, T. Joseph

    1993-01-01

    Fading channel effects on a transmitted communication signal are simulated with both frequency and time variations using a channel scattering function to affect the transmitted signal. A conventional channel scattering function is converted to a series of channel realizations by multiplying the square root of the channel scattering function by a complex number of which the real and imaginary parts are each independent variables. The two-dimensional inverse-FFT of this complex-valued channel realization yields a matrix of channel coefficients that provide a complete frequency-time description of the channel. The transmitted radio signal is segmented to provide a series of transmitted signal and each segment is subject to FFT to generate a series of signal coefficient matrices. The channel coefficient matrices and signal coefficient matrices are then multiplied and subjected to inverse-FFT to output a signal representing the received affected radio signal. A variety of channel scattering functions can be used to characterize the response of a transmitter-receiver system to such atmospheric effects.

  16. 75 FR 3666 - Digital Performance Right in Sound Recordings and Ephemeral Recordings for a New Subscription...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-22

    ... facilitating certain digital audio transmissions, including those made by new subscription services. 17 U.S.C... have conducted one proceeding pursuant to these provisions. See 70 FR 72471, 72472 (December 5, 2005... subscription service that ``performs sound recordings on digital audio channels programmed by the licensee...

  17. 75 FR 14074 - Digital Performance Right in Sound Recordings and Ephemeral Recordings for a New Subscription...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-24

    ...) allows the making of ephemeral reproductions for the purpose of facilitating certain digital audio... pursuant to these provisions. See 70 FR 72471, 72472 (December 5, 2005) (after receipt of petition... sound recordings on digital audio channels programmed by the licensee for transmission by a...

  18. Digital work-flow

    PubMed Central

    MARSANGO, V.; BOLLERO, R.; D’OVIDIO, N.; MIRANDA, M.; BOLLERO, P.; BARLATTANI, A.

    2014-01-01

    SUMMARY Objective. The project presents a clinical case in which the digital work-flow procedure was applied for a prosthetic rehabilitation in natural teeth and implants. Materials. Digital work-flow uses patient’s photo for the aesthetic’s planning, digital smile technology for the simulation of the final restoration and real time scanning to register the two arches. Than the scanning are sent to the laboratory that proceed with CAD-CAM production. Results. Digital work-flow offers the opportunities to easily speak with laboratory and patients, gives better clinical results and demonstrated to be a less invasiveness method for the patient. Conclusion. Intra-oral scanner, digital smile design, preview using digital wax-up, CAD-CAM production, are new predictable opportunities for prosthetic team. This work-flow, compared with traditional methods, is faster, more precise and predictable. PMID:25694797

  19. Digital radiography: an overview.

    PubMed

    Parks, Edwin T; Williamson, Gail F

    2002-11-15

    Since the discovery of X-rays in 1895, film has been the primary medium for capturing, displaying, and storing radiographic images. It is a technology that dental practitioners are the most familiar and comfortable with in terms of technique and interpretation. Digital radiography is the latest advancement in dental imaging and is slowly being adopted by the dental profession. Digital imaging incorporates computer technology in the capture, display, enhancement, and storage of direct radiographic images. Digital imaging offers some distinct advantages over film, but like any emerging technology, it presents new and different challenges for the practitioner to overcome. This article presents an overview of digital imaging including basic terminology and comparisons with film-based imaging. The principles of direct and indirect digital imaging modalities, intraoral and extraoral applications, image processing, and diagnostic efficacy will be discussed. In addition, the article will provide a list of questions dentists should consider prior to purchasing digital imaging systems for their practice. PMID:12444400

  20. Playground Safety.

    ERIC Educational Resources Information Center

    Sipes, James L.

    2000-01-01

    Discusses the issues of risk, liability, and fun when landscaping playgrounds with safety in mind. The importance of playground surfaces and several preventive measures landscapers can use to reduce the risk of injury are discussed. Concluding comments address playground design features and liability. (GR)

  1. School Safety.

    ERIC Educational Resources Information Center

    The Newsletter of the Comprehensive Center-Region VI, 1999

    1999-01-01

    The articles in this issue dealing with school safety discusses what rural and small urban settings are doing to prevent violence and to educate young people about prosocial alternatives to violence. The research is quite clear that female, minority, and gay students are the targets of a disproportionate amount of harassment and violence, both in…

  2. Safety First!

    ERIC Educational Resources Information Center

    Longfield, Judith

    2006-01-01

    In this article, the author relates how a hands-on chemistry investigation provided her the inspiration to develop an effective safety lesson for her third grade chemistry class. She began the lesson by demonstrating the use of pH indicator paper to show that ordinary household (white) vinegar was an acid. With the students, she wondered aloud…

  3. Art Safety.

    ERIC Educational Resources Information Center

    BCATA Journal for Art Teachers, 1991

    1991-01-01

    Advocating that Canadian art programs should use and model environmentally safe practices, the articles in this journal focus on issues of safe practices in art education. Articles are: (1) "What is WHMIS?"; (2) "Safety Precautions for Specific Art Processes"; (3) "Toxic Substances"; (4) "Using Clay, Glazes, and Kilns Safely in the Classroom"…

  4. Digital Longitudinal Tomosynthesis

    NASA Astrophysics Data System (ADS)

    Rimkus, Daniel Steven

    1985-12-01

    The purpose of this dissertation was to investigate the clinical utility of digital longitudinal tomosynthesis in radiology. By acquiring a finite group of digital images during a longitudinal tomographic exposure, and processing these images, tomographic planes, other than the fulcrum plane, can be reconstructed. This process is now termed "tomosynthesis". A prototype system utilizing this technique was developed. Both phantom and patient studies were done with this system. The phantom studies were evaluated by subjective, visual criterion and by quantitative analysis of edge sharpness and noise in the reconstructions. Two groups of patients and one volunteer were studied. The first patient group consisted of 8 patients undergoing intravenous urography (IVU). These patients had digital tomography and film tomography of the abdomen. The second patient group consisted of 4 patients with lung cancer admitted to the hospital for laser resection of endobronchial tumor. These patients had mediastinal digital tomograms to evaluate the trachea and mainstem bronchi. The knee of one volunteer was imaged by film tomography and digital tomography. The results of the phantom studies showed that the digital reconstructions accurately produced images of the desired planes. The edge sharpness of the reconstructions approached that of the acquired images. Adequate reconstructions were achieved with as few as 5 images acquired during the exposure, with the quality of the reconstructions improving as the number of images acquired increased. The IVU patients' digital studies had less contrast and spatial resolution than the film tomograms. The single renal lesion visible on the film tomograms was also visible in the digital images. The digital mediastinal studies were felt by several radiologists to be superior to a standard chest xray in evaluating the airways. The digital images of the volunteer's knee showed many of the same anatomic features as the film tomogram, but the digital

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  6. TEMPERATURE-MONITORING AND SAFETY-CONTROL DEVICE

    EPA Science Inventory

    A two channel (sensitive) temperature monitor is described, and a parts list and wiring diagram are given. This equipment can be used as a safety shut-off or alarm system, or both. The sensitivity is 0.3C.

  7. Digital In, Digital Out: Digital Editing with Firewire.

    ERIC Educational Resources Information Center

    Doyle, Bob; Sauer, Jeff

    1997-01-01

    Reviews linear and nonlinear digital video (DV) editing equipment and software, using the IEEE 1394 (FireWire) connector. Includes a chart listing specifications and rating eight DV editing systems, reviews two DV still-photo cameras, and previews beta DV products. (PEN)

  8. Debunking the "Digital Native": Beyond Digital Apartheid, towards Digital Democracy

    ERIC Educational Resources Information Center

    Brown, C.; Czerniewicz, L.

    2010-01-01

    This paper interrogates the currently pervasive discourse of the "net generation" finding the concept of the "digital native" especially problematic, both empirically and conceptually. We draw on a research project of South African higher education students' access to and use of Information and Communication Technologies (ICTs) to show that age is…

  9. Digital security technology simplified.

    PubMed

    Scaglione, Bernard J

    2007-01-01

    Digital security technology is making great strides in replacing analog and other traditional security systems including CCTV card access, personal identification and alarm monitoring applications. Like any new technology, the author says, it is important to understand its benefits and limitations before purchasing and installing, to ensure its proper operation and effectiveness. This article is a primer for security directors on how digital technology works. It provides an understanding of the key components which make up the foundation for digital security systems, focusing on three key aspects of the digital security world: the security network, IP cameras and IP recorders. PMID:17907609

  10. Digital solar system geology

    NASA Technical Reports Server (NTRS)

    Batson, R. M.; Kozak, R. C.; Isbell, Nancy K.

    1991-01-01

    All available synoptic maps of the solid-surface bodies of the Solar System were digitized for presentation in the planned Atlas of the Solar System by Greeley and Batson. Since the last report (Batson et al., 1990), preliminary Uranian satellite maps were replaced with improved versions, Galilean satellite geology was simplified and digitized, structure was added to many maps, and the maps were converted to a standard format, with corresponding standing colors for the mapped units. Following these changes, the maps were re-reviewed by their authors and are now undergoing final editing before preparation for publication. In some cases (for Mercury, Venus, and Mars), more detailed maps were digitized and then simplified for the Atlas. Other detailed maps are planned to be digitized in the coming year for the Moon and the Galilean satellites. For most of the remaining bodies such as the Uranian satellites, the current digitized versions contain virtually all the detail that can be mapped given the available data; those versions will be unchanged for the Atlas. These digital geologic maps are archived at the digital scale of 1/16 degree/ pixel, in sinusoidal format. The availability of geology of the Solar System in a digital database will facilitate comparisons and integration with other data: digitized lunar geologic maps have already been used in a comparison with Galileo SSI observations of the Moon.

  11. Experiments in digital literacy.

    PubMed

    Eshet-Alkali, Yoram; Amichai-Hamburger, Yair

    2004-08-01

    Having digital literacy requires more than just the ability to use software or to operate a digital device; it includes a large variety of complex skills such as cognitive, motoric, sociological, and emotional that users need to have in order to use digital environments effectively. A conceptual model that was recently described by the authors suggests that digital literacy comprises five major digital skills: photo-visual skills ("reading" instructions from graphical displays), reproduction skills (utilizing digital reproduction to create new, meaningful materials from preexisting ones), branching skills (constructing knowledge from non-linear, hypertextual navigation), information skills (evaluating the quality and validity of information), and socio-emotional skills (understanding the "rules" that prevail in cyberspace and applying this understanding in online cyberspace communication). The present paper presents results from a performance-based pioneer study that investigated the application of the above digital literacy skills conceptual model among different groups of scholars. Results clearly indicate that the younger participants performed better than the older ones, with photo-visual and branching literacy tasks, whereas the older participants were found to be more literate in reproduction and information literacy tasks. Research results shed light on the cognitive skills that users utilize in performing with digital environments, and provide educators and software developers with helpful guidelines for designing better user-centered digital environments. PMID:15331029

  12. Digitization Best Practices

    SciTech Connect

    Xue, Fei; Holtkamp, Irma S.; Knudson, Frances L.

    2012-07-31

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

  13. Exploring digital professionalism.

    PubMed

    Ellaway, Rachel H; Coral, Janet; Topps, David; Topps, Maureen

    2015-01-01

    The widespread use of digital media (both computing devices and the services they access) has blurred the boundaries between our personal and professional lives. Contemporary students are the last to remember a time before the widespread use of the Internet and they will be the first to practice in a largely e-health environment. This article explores concepts of digital professionalism and their place in contemporary medical education, and proposes a series of principles of digital professionalism to guide teaching, learning and practice in the healthcare professions. Despite the many risks and fears surrounding their use, digital media are not an intrinsic threat to medical professionalism. Professionals should maintain the capacity for deliberate, ethical, and accountable practice when using digital media. The authors describe a digital professionalism framework structured around concepts of proficiency, reputation, and responsibility. Digital professionalism can be integrated into medical education using strategies based on awareness, alignment, assessment, and accountability. These principles of digital professionalism provide a way for medical students and medical practitioners to embrace the positive aspects of digital media use while being mindful and deliberate in its use to avoid or minimize any negative consequences. PMID:26030375

  14. Jamming in Vertical Channels

    NASA Astrophysics Data System (ADS)

    Baxter, G. William; Steel, Fiona

    2011-03-01

    We study jamming of low aspect-ratio cylindrical Delrin grains in a vertical channel. Grain heights are less than their diameter so the grains resemble antacid tablets, coins, or poker chips. These grains are allowed to fall through a vertical channel with a square cross section where the channel width is greater than the diameter of a grain and constant throughout the length of the channel with no obstructions or constrictions. Grains are sometimes observed to form jams, stable structures supported by the channel walls with no support beneath them. The probability of jam occurrence and the strength or robustness of a jam is effected by grain and channel sizes. We will present experimental measurements of the jamming probability and jam strength in this system and discuss the relationship of these results to other experiments and theories. Supported by an Undergraduate Research Grant from Penn State Erie, The Behrend College.

  15. Processor for high-density digital tape-recorded signals

    NASA Technical Reports Server (NTRS)

    Ashlock, J. C.

    1973-01-01

    Linear filter and detection theory can bear on problem of reconstructing recorded bit stream. Problem can be taken from realm of nonlinear problems even though basic record process is still recognized as highly nonlinear. Digital tape recorder can be modeled as particular type of linear communication channel with intersymbol interference.

  16. The land mobile satellite communication channel - Recording, statistics, and channel model

    NASA Astrophysics Data System (ADS)

    Lutz, Erich; Cygan, Daniel; Dippold, Michael; Dolainsky, Frank; Papke, Wolfgang

    1991-05-01

    The communication channel between the MARECS satellite at 26 deg W and a cruising van was measured and recorded in European areas exhibiting satellite elevations from 13 to 43 deg. Different environments and mobile antennas were tested. Results of an extensive statistical evaluation include spectra of the fading amplitude, probability density, and distribution of the received signal power as well as the percentage of time for fade and nonfade periods. Based on the physical phenomena of multipath fading and signal shadowing, an analog model of the land mobile satellite channel which can readily be used for software and hardware fading simulation is developed. The most important parameter of this model is the time-share of shadowing, A, ranging from less than 1 percent on southern highways to 89 percent in the city of Stockholm. The Rice factor, c, which characterizes the channel during unshadowed periods, can vary from 3.9 to 18.1 dB. For analytical purposes, the land mobile satellite channel can be represented by a digital two-state Gilbert-Elliott model. For DPSK (differential phase-shift keying) modulation with a 10-dB signal-to-noise ratio in the satellite link, the mean bit error probability in the unshadowed channel state is typically in the range of 0.0001-0.01, while it is around 0.3 in the shadowed channel state. With regard to data transmission, block error probability density, error gap distribution, and block error probability are discussed.

  17. Channel control ASIC for the CMS hadron calorimeter front end readout module

    SciTech Connect

    Ray Yarema et al.

    2002-09-26

    The Channel Control ASIC (CCA) is used along with a custom Charge Integrator and Encoder (QIE) ASIC to digitize signals from the hybrid photo diodes (HPDs) and photomultiplier tubes (PMTs) in the CMS hadron calorimeter. The CCA sits between the QIE and the data acquisition system. All digital signals to and from the QIE pass through the CCA chip. One CCA chip interfaces with two QIE channels. The CCA provides individually delayed clocks to each of the QIE chips in addition to various control signals. The QIE sends digitized PMT or HPD signals and time slice information to the CCA, which sends the data to the data acquisition system through an optical link.

  18. CHANNEL MORPHOLOGY TOOL (CMT): A GIS-BASED AUTOMATED EXTRACTION MODEL FOR CHANNEL GEOMETRY

    SciTech Connect

    JUDI, DAVID; KALYANAPU, ALFRED; MCPHERSON, TIMOTHY; BERSCHEID, ALAN

    2007-01-17

    This paper describes an automated Channel Morphology Tool (CMT) developed in ArcGIS 9.1 environment. The CMT creates cross-sections along a stream centerline and uses a digital elevation model (DEM) to create station points with elevations along each of the cross-sections. The generated cross-sections may then be exported into a hydraulic model. Along with the rapid cross-section generation the CMT also eliminates any cross-section overlaps that might occur due to the sinuosity of the channels using the Cross-section Overlap Correction Algorithm (COCoA). The CMT was tested by extracting cross-sections from a 5-m DEM for a 50-km channel length in Houston, Texas. The extracted cross-sections were compared directly with surveyed cross-sections in terms of the cross-section area. Results indicated that the CMT-generated cross-sections satisfactorily matched the surveyed data.

  19. Symmetrization for redundant channels

    NASA Technical Reports Server (NTRS)

    Tulplue, Bhalchandra R. (Inventor); Collins, Robert E. (Inventor)

    1988-01-01

    A plurality of redundant channels in a system each contain a global image of all the configuration data bases in each of the channels in the system. Each global image is updated periodically from each of the other channels via cross channel data links. The global images of the local configuration data bases in each channel are separately symmetrized using a voting process to generate a system signal configuration data base which is not written into by any other routine and is available for indicating the status of the system within each channel. Equalization may be imposed on a suspect signal and a number of chances for that signal to heal itself are provided before excluding it from future votes. Reconfiguration is accomplished upon detecting a channel which is deemed invalid. A reset function is provided which permits an externally generated reset signal to permit a previously excluded channel to be reincluded within the system. The updating of global images and/or the symmetrization process may be accomplished at substantially the same time within a synchronized time frame common to all channels.

  20. Phosphoinositides regulate ion channels

    PubMed Central

    Hille, Bertil; Dickson, Eamonn J.; Kruse, Martin; Vivas, Oscar; Suh, Byung-Chang

    2014-01-01

    Phosphoinositides serve as signature motifs for different cellular membranes and often are required for the function of membrane proteins. Here, we summarize clear evidence supporting the concept that many ion channels are regulated by membrane phosphoinositides. We describe tools used to test their dependence on phosphoinositides, especially phosphatidylinositol 4,5-bisphosphate, and consider mechanisms and biological meanings of phosphoinositide regulation of ion channels. This lipid regulation can underlie changes of channel activity and electrical excitability in response to receptors. Since different intracellular membranes have different lipid compositions, the activity of ion channels still in transit towards their final destination membrane may be suppressed until they reach an optimal lipid environment. PMID:25241941

  1. Historical Channel Changes in Cache Creek, Capay Valley, California

    NASA Astrophysics Data System (ADS)

    Higgins, S. A.; Kamman, G. R.

    2009-12-01

    Historical channel changes were assessed for the 21-mile segment of Cache Creek through Capay Valley in order to evaluate temporal changes in stream channel morphology. The Capay Valley segment of Cache Creek is primarily a low-gradient channel with a gravel/cobble substrate. Hydrologic conditions have been affected by dam operations that store runoff during the wet season and deliver water during the dry season for downstream irrigation uses. Widespread distribution of invasive plant species has altered the condition of the riparian corridor. The assessment evaluated a hypothesis that historical changes in hydrology and vegetation cover have triggered changes in geomorphic conditions. Historic channel alignments were digitized to assess planform channel adjustments. Results illustrate a dynamic system with frequent channel movements throughout the historic period. Evaluation of longitudinal channel adjustments revealed a relatively stable bed surface elevation since the 1930’s. Comparisons of cross-sectional channel geometry for topographic profiles surveyed in 1984 were compared to equivalent features in a LiDAR survey from 2008. The comparisons show a relatively consistent channel geometry that has maintained a similar form despite rather large planform adjustments with areas of bank retreat in excess of 500 feet. Results suggest that the study reach has maintained a relatively stable morphology through a series of dynamic planform adjustments during the historic period.

  2. A review of channel selection algorithms for EEG signal processing

    NASA Astrophysics Data System (ADS)

    Alotaiby, Turky; El-Samie, Fathi E. Abd; Alshebeili, Saleh A.; Ahmad, Ishtiaq

    2015-12-01

    Digital processing of electroencephalography (EEG) signals has now been popularly used in a wide variety of applications such as seizure detection/prediction, motor imagery classification, mental task classification, emotion classification, sleep state classification, and drug effects diagnosis. With the large number of EEG channels acquired, it has become apparent that efficient channel selection algorithms are needed with varying importance from one application to another. The main purpose of the channel selection process is threefold: (i) to reduce the computational complexity of any processing task performed on EEG signals by selecting the relevant channels and hence extracting the features of major importance, (ii) to reduce the amount of overfitting that may arise due to the utilization of unnecessary channels, for the purpose of improving the performance, and (iii) to reduce the setup time in some applications. Signal processing tools such as time-domain analysis, power spectral estimation, and wavelet transform have been used for feature extraction and hence for channel selection in most of channel selection algorithms. In addition, different evaluation approaches such as filtering, wrapper, embedded, hybrid, and human-based techniques have been widely used for the evaluation of the selected subset of channels. In this paper, we survey the recent developments in the field of EEG channel selection methods along with their applications and classify these methods according to the evaluation approach.

  3. Digital rights language support for evolving digital cinema requirements

    NASA Astrophysics Data System (ADS)

    Orri, Xavier; Mas, Joan-Maria; Macq, Benoit M. M.

    2003-06-01

    Digital cinema can be defined as the digital electronic distribution and display of theatrical film content or live material to the theatre. However, this simple definition does not reflect the complex mesh of balanced business relationships between the different parties involved in the worldwide cinematic distribution. Its transition from an analogue to a digital business will happen progressively, starting with only content being digitally distributed and going until an all-digital business. From these facts derive strong requirements on digital rights management (DRM) systems for digital cinema and therefore on the digital rights language supporting it. This paper explores the requirements imposed by the cinematic distribution model and by its progressive transition to digital, and the impact these have on digital rights languages. We analyze the support provided by different digital rights languages, identifying weaknesses and exploring solutions in fulfilling the requirements of the digital cinema distribution model.

  4. REVIEW OF NRC APPROVED DIGITAL CONTROL SYSTEMS ANALYSIS

    SciTech Connect

    D.W. Markman

    1999-09-17

    Preliminary design concepts for the proposed Subsurface Repository at Yucca Mountain indicate extensive reliance on modern, computer-based, digital control technologies. The purpose of this analysis is to investigate the degree to which the U. S. Nuclear Regulatory Commission (NRC) has accepted and approved the use of digital control technology for safety-related applications within the nuclear power industry. This analysis reviews cases of existing digitally-based control systems that have been approved by the NRC. These cases can serve as precedence for using similar types of digitally-based control technologies within the Subsurface Repository. While it is anticipated that the Yucca Mountain Project (YMP) will not contain control systems as complex as those required for a nuclear power plant, the review of these existing NRC approved applications will provide the YMP with valuable insight into the NRCs review process and design expectations for safety-related digital control systems. According to the YMP Compliance Program Guidance, portions of various NUREGS, Regulatory Guidelines, and nuclear IEEE standards the nuclear power plant safety related concept would be applied to some of the designs on a case-by-case basis. This analysis will consider key design methods, capabilities, successes, and important limitations or problems of selected control systems that have been approved for use in the Nuclear Power industry. An additional purpose of this analysis is to provide background information in support of further development of design criteria for the YMP. The scope and primary objectives of this analysis are to: (1) Identify and research the extent and precedence of digital control and remotely operated systems approved by the NRC for the nuclear power industry. Help provide a basis for using and relying on digital technologies for nuclear related safety critical applications. (2) Identify the basic control architecture and methods of key digital control

  5. Preliminary studies on the impact of smoke on digital equipment

    SciTech Connect

    Tanaka, T.J.; Korsah, K.; Antonescu, C.

    1995-12-01

    Last year the USNRC initiated a program at Sandia National Laboratories to determine the potential impact of smoke on advanced safety-related digitial instrumentation. In recognition of the fact that the reliability of safety-related equipment during or shortly after a fire in a nuclear power plant is more risk significant than long-term effects, we are concentrating on short-term failures. We exposed a multiplexer module board to three different types of smoke to determine whether the smoke would affect its operation. The operation of the multiplexer board was halted by one out of the three smoke exposures. In coordination with Oak Ridge National Laboratory, an experimental digital safety system was also smoke tested. The series of tests showed that smoke can cause potentially serious failures of a safety system. Most of these failures were intermittent and showed that smoke can temporarily interrupt communication between digital systems.

  6. Safety harness

    DOEpatents

    Gunter, Larry W.

    1993-01-01

    A safety harness to be worn by a worker, especially a worker wearing a plastic suit thereunder for protection in a radioactive or chemically hostile environment, which safety harness comprises a torso surrounding portion with at least one horizontal strap for adjustably securing the harness about the torso, two vertical shoulder straps with rings just forward of the of the peak of the shoulders for attaching a life-line and a pair of adjustable leg supporting straps releasibly attachable to the torso surrounding portion. In the event of a fall, the weight of the worker, when his fall is broken and he is suspended from the rings with his body angled slightly back and chest up, will be borne by the portion of the leg straps behind his buttocks rather than between his legs. Furthermore, the supporting straps do not restrict the air supplied through hoses into his suit when so suspended.

  7. Navigation study on improvements to existing federal navigation channels Arthur Kill Channel, Howland Hook Marine Terminal, Staten Island, New York

    SciTech Connect

    Not Available

    1985-06-01

    Improvements to the Arthur Kill Channel from the confluence of the Kill Van Kull Channel, the Arthur Kill Channel, and Newark Bay, along the Arthur Kill to the vicinity of Howland Hook Marine Terminal on Staten Island, New York are proposed. In addition, the study area was extended south from Howland Hook Terminal for approximately one mile in order to serve two oil terminals. The recommended improvements would include deepening to various depths down to 45 feet mean low water (MLW), widening the channel for unrestricted two-way traffic, and the creation of a turning basin. Specifically, a 41-foot MLW deep channel would be dredged in the previously authorized 35-foot MLW project in the Arthur Kill Channel from its confluence with the Newark Bay and Kill Van Kull channels to the Howland Hook Marine Terminal for a distance of approximately 2.1 miles. Also recommended are selected widenings and realignments of the channel at a depth of 41 feet in the interest of navigational safety. Additionally, a 40-foot MLW channel is proposed in the previously authorized 35-foot MLW project in the Arthur Kill Channel from the Howland Hook Marine Terminal to the Exxon Bayway and Gulfport facilities for a distance of approximately one mile. The channel would be selectively realigned to a 40-foot depth for navigational safety. No final determination has been made regarding the disposal of dredged material due to the uncertainty of available upland sites at this time. The turning basin would lie in the Kill Van Kull Channel at Bergen Point, where vessels turn from Kill Van Kull into Arthur Kill and Newark Bay. Total cost of the recommended plan is $49.4 million; the benefit-cost ratio is 4.35. The plan would take 4 years for completion and would have a projected life of 50 years.

  8. Safety valve

    DOEpatents

    Bergman, Ulf C.

    1984-01-01

    The safety valve contains a resilient gland to be held between a valve seat and a valve member and is secured to the valve member by a sleeve surrounding the end of the valve member adjacent to the valve seat. The sleeve is movable relative to the valve member through a limited axial distance and a gap exists between said valve member and said sleeve.

  9. Farm Safety

    PubMed Central

    Wilson, G. S.

    1966-01-01

    Accident and safety are related terms; the higher the accident rate in any industry, the greater is the need for safety measures designed to prevent accidents. This article discusses the accident and safety problems in agriculture, which includes horticulture and forestry. There is still a tendency among townspeople to think of the countryside as peaceful and tranquil, a place where nothing happens very quickly and far removed from violent death or crippling injury. This pleasant rustic picture has undergone a striking change in the last 30 years owing to considerable agricultural mechanization and the development of chemical pesticides, which have brought new dangers to those who live and work on the land. Although men have readily adapted themselves to new machines and methods, they have not proved as able to recognize new dangers and learn how to guard against them. In consequence, accidents have increased to such an extent that the whole industry has realized the need for positive preventive measures. In this country, it is generally accepted that an employer of labour has a responsibility to provide safe working conditions for those he employs. Farm safety legislation goes a little further and usually requires an employer to provide necessary safeguards, with the added requirement on a worker to make use of them. It is a feature of accident prevention work that it never reaches a stage when it can be regarded as complete. Even when a reduction in accidents has been achieved, the effort must be sustained or the trend will be quickly reversed. Images PMID:5904095

  10. Implementation of a 622 Mbps Digital Modem

    NASA Technical Reports Server (NTRS)

    Kifle, Muli; Bizon, Thomas P.; Nguyen, Nam T.; Tran, Quang K.; Mortensen, Dale J.

    2002-01-01

    This paper presents the implementation and initial test results of an Orthogonal Frequency Division Multiplexing (OFDM) digital modem (modulator and demodulator) with an aggregate information throughput of 622 megabits per second (Mbps). The OFDM waveform is constructed by dividing an incoming data stream into four channels, each channel using either a 16-ary Quadrature Amplitude Modulation (16QAM) scheme or an 8-Phase Shift Keying (8PSK) scheme. The generation and detection of the composite waveform are performed using Discrete Fourier Transform (DFT) and polyphase filtering, to digitally stack and band-limit the individual carriers respectively. The four-channel OFDM approach enables the implementation of a modem that can be both power and bandwidth efficient, with sufficient parallelism to meet higher data rate goals. As a result, the OFDM modem requires only a 240 MHz bandwidth to transmit 622 Mbps. Hardware and simulation results in the form of spectrum diagrams and bit-error-rate (BER) curves are also presented in this paper.

  11. The Digital Absurd

    ERIC Educational Resources Information Center

    Hodges, Steve

    2010-01-01

    I believe that the concept of the absurd, as described in philosophy and reflected in works of drama and literature, provides an unusual and helpful perspective from which to view the emerging field of digital media. In my opinion, absurd principles can help us understand the mixed feelings we may have when engaging with digital media: joy and…

  12. Navigate the Digital Rapids

    ERIC Educational Resources Information Center

    Lindsay, Julie; Davis, Vicki

    2010-01-01

    How can teachers teach digital citizenship when the digital landscape is changing so rapidly? How can teachers teach proper online social interactions when the students are outside their classroom and thus outside their control? Will encouraging students to engage in global collaborative environments land teachers in hot water? These are the…

  13. Digital Media and Learning

    ERIC Educational Resources Information Center

    John D. and Catherine T. MacArthur Foundation, 2012

    2012-01-01

    MacArthur launched the digital media and learning initiative in 2006 to explore how digital media are changing the way young people learn, socialize, communicate, and play. Since 2006, the Foundation has awarded grants totaling more than $100 million for research, development of innovative new technologies, new learning environments for youth,…

  14. Digital automatic gain control

    NASA Technical Reports Server (NTRS)

    Uzdy, Z.

    1980-01-01

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

  15. Digital rotation measurement unit

    DOEpatents

    Sanderson, S.N.

    1983-09-30

    A digital rotation indicator is disclosed for monitoring the position of a valve member having a movable actuator. The indicator utilizes mercury switches adapted to move in cooperation with the actuator. Each of the switches produces an output as it changes state when the actuator moves. A direction detection circuit is connected to the switches to produce a first digital signal indicative of the direction of rotation of the actuator. A count pulse generating circuit is also connected to the switches to produce a second digital pulse signal having count pulses corresponding to a change of state of any of the mercury switches. A reset pulse generating circuit is provided to generate a reset pulse each time a count pulse is generated. An up/down counter is connected to receive the first digital pulse signal and the second digital pulse signal and to count the pulses of the second digital pulse signal either up or down depending upon the instantaneous digital value of the first digital signal whereby a running count indicative of the movement of the actuator is maintained.

  16. Occupying the Digital Humanities

    ERIC Educational Resources Information Center

    Rice, Jeff

    2013-01-01

    This essay questions the digital humanities' dependence on interpretation and critique as strategies for reading and responding to texts. Instead, the essay proposes suggestion as a digital rhetorical practice, one that does not replace hermeneutics, but instead offers alternative ways to respond to texts. The essay uses the Occupy movement as an…

  17. The Digital Vaults

    ERIC Educational Resources Information Center

    Isaacs, Suzanne; Potter, Lee Ann

    2008-01-01

    This article explores the Digital Vaults and offers suggestions in introducing this site to students. The Digital Vaults, inspired by the permanent Public Vaults exhibition launched by the National Archives in 2004, is not just another website, but it designed to be an online exhibit and teaching tool, by offering both exposure to historical…

  18. Digital Pinhole Camera

    ERIC Educational Resources Information Center

    Lancor, Rachael; Lancor, Brian

    2014-01-01

    In this article we describe how the classic pinhole camera demonstration can be adapted for use with digital cameras. Students can easily explore the effects of the size of the pinhole and its distance from the sensor on exposure time, magnification, and image quality. Instructions for constructing a digital pinhole camera and our method for…

  19. Digital Collections Inventory Report.

    ERIC Educational Resources Information Center

    McClung, Patricia A.

    This report is intended to inform and stimulate discussion on digital library programs as well as the potential usefulness, scope, and desired features of future inventories of online digital collections. It describes a joint project by the Commission on Preservation and Access and the Council on Library Resources to determine the extent to which…

  20. Cresting the Digital Divide

    ERIC Educational Resources Information Center

    Gregory, Kay; Steelman, Joyce

    2008-01-01

    Catawba Valley Community College has introduced digital storytelling (DS), an innovative instructional method that has produced extraordinary results. Digital storytelling uses affordable software to craft powerful multimedia presentations of student writing. Students create 3-to-4-minute movies with images, voiceovers, and music. This project…

  1. Digital Video Editing

    ERIC Educational Resources Information Center

    McConnell, Terry

    2004-01-01

    Monica Adams, head librarian at Robinson Secondary in Fairfax country, Virginia, states that librarians should have the technical knowledge to support projects related to digital video editing. The process of digital video editing and the cables, storage issues and the computer system with software is described.

  2. Will Digital Texts Succeed?

    ERIC Educational Resources Information Center

    Acker, Stephen R.

    2008-01-01

    With faculty changing instructional practices to take advantage of customizable, focused content (and digital delivery of that content), many people assume that digital distribution is the answer to bringing the costs of course content delivery in line. But the picture just isn't that simple. A wide continuum of options is available to faculty and…

  3. Shaping Digital Library Content.

    ERIC Educational Resources Information Center

    Miller, Rush G.

    2002-01-01

    Explores issues related to the selection and purchase of digital content in academic libraries, including commercially-produced databases, electronic journals, and books and other electronic resources that are purchased from vendors; and in-house digitization projects. Considers the degree to which standard collection management principles apply.…

  4. Optimization of digital designs

    NASA Technical Reports Server (NTRS)

    Whitaker, Sterling R. (Inventor); Miles, Lowell H. (Inventor)

    2009-01-01

    An application specific integrated circuit is optimized by translating a first representation of its digital design to a second representation. The second representation includes multiple syntactic expressions that admit a representation of a higher-order function of base Boolean values. The syntactic expressions are manipulated to form a third representation of the digital design.

  5. Music Instruction Goes Digital

    ERIC Educational Resources Information Center

    Demski, Jennifer

    2011-01-01

    Faced with meager enrollment in band, orchestra, and choir programs, schools are using digital technology to excite students about creating music on today's terms. This article discusses how music educators reinvent their profession by acknowledging and incorporating the way students interact with music today--digitally. Bill Evans, a music…

  6. Digital Image Access & Retrieval.

    ERIC Educational Resources Information Center

    Heidorn, P. Bryan, Ed.; Sandore, Beth, Ed.

    Recent technological advances in computing and digital imaging technology have had immediate and permanent consequences for visual resource collections. Libraries are involved in organizing and managing large visual resource collections. The central challenges in working with digital image collections mirror those that libraries have sought to…

  7. Creating Digital Authors

    ERIC Educational Resources Information Center

    Zoch, Melody; Langston-DeMott, Brooke; Adams-Budde, Melissa

    2014-01-01

    Elementary students find themselves engaged and learning at a digital writing camp. The authors find that such elementary students usually have limited access to technology at home and school, and posit that teachers should do all they can to give them more access to and experience in digital composing. Students were motivated and learned to use…

  8. Writing and Digital Media

    ERIC Educational Resources Information Center

    van Waes, Luuk, Ed.; Leijten, Marielle, Ed.; Neuwirth, Chris, Ed.

    2006-01-01

    Digital media has become an increasingly powerful force in modern society. This volume brings together outstanding European, American and Australian research in "writing and digital media" and explores its cognitive, social and cultural implications. In addition to presenting programs of original research by internationally known scholars from a…

  9. Digital Signature Management.

    ERIC Educational Resources Information Center

    Hassler, Vesna; Biely, Helmut

    1999-01-01

    Describes the Digital Signature Project that was developed in Austria to establish an infrastructure for applying smart card-based digital signatures in banking and electronic-commerce applications. Discusses the need to conform to international standards, an international certification infrastructure, and security features for a public directory…

  10. Digital Knowledge Resources

    ERIC Educational Resources Information Center

    Pandian, M. Paul

    2008-01-01

    Technology has revolutionized the concept of libraries. Networking and computing technologies have now become sufficiently advanced to support the design and deployment of large digital libraries which are capable of supporting the conventional end-user functions. Digital libraries are a natural extension of the evolution in which libraries have…

  11. Taming the Digital Beast

    ERIC Educational Resources Information Center

    Patrizio, Andy

    2006-01-01

    As more and more schools move to digital repositories, it seems inevitable that the knowledge accumulated across universities will go digital. How smoothly an institution makes that transition will depend on how well its project is planned from inception, and how well it structure its data. All of the administrators and educators the authors spoke…

  12. Scholars | Digital Representation | Publishing

    ERIC Educational Resources Information Center

    Hodgson, Justin

    2014-01-01

    Understanding the current state of digital publishing means that writers can now do more and say more in more ways than ever before in human history. As modes, methods, media and mechanisms of expression mutate into newer and newer digital forms, writers find themselves at a moment when they can create, critique collaborate, and comment according…

  13. Changing State Digital Libraries

    ERIC Educational Resources Information Center

    Pappas, Marjorie L.

    2006-01-01

    Research has shown that state virtual or digital libraries are evolving into websites that are loaded with free resources, subscription databases, and instructional tools. In this article, the author explores these evolving libraries based on the following questions: (1) How user-friendly are the state digital libraries?; (2) How do state digital…

  14. Fundamentals of Digital Logic.

    ERIC Educational Resources Information Center

    Noell, Monica L.

    This course is designed to prepare electronics personnel for further training in digital techniques, presenting need to know information that is basic to any maintenance course on digital equipment. It consists of seven study units: (1) binary arithmetic; (2) boolean algebra; (3) logic gates; (4) logic flip-flops; (5) nonlogic circuits; (6)…

  15. ISDN: The Digital Difference.

    ERIC Educational Resources Information Center

    Piedmo, Greg

    1995-01-01

    Integrated services digital network (ISDN) is a dial-up digital transmission service supporting transmission of audio, video, and text data over standard copper telephone wires or fiber optic cables. Advantages of ISDN over analog transmission include the ability of one phone line to support up to three simultaneous, separate conversations (phone,…

  16. Digital communications study

    NASA Technical Reports Server (NTRS)

    Boorstyn, R. R.

    1973-01-01

    Research is reported dealing with problems of digital data transmission and computer communications networks. The results of four individual studies are presented which include: (1) signal processing with finite state machines, (2) signal parameter estimation from discrete-time observations, (3) digital filtering for radar signal processing applications, and (4) multiple server queues where all servers are not identical.

  17. Towards a Digital Future

    ERIC Educational Resources Information Center

    Thomson, Rachel

    2009-01-01

    A month ago, a French court ruled that internet access is a basic human right. Gordon Brown has said it is as crucial for people as electricity and water. Yet, 17 million Britons are still excluded from digital technology and an estimated 13 per cent of the population--some six million people--are both socially and digitally excluded. There are…

  18. MPEG-21 in broadcasting: the novel digital broadcast item model

    NASA Astrophysics Data System (ADS)

    Lugmayr, Artur R.; Touimi, Abdellatif B.; Kaneko, Itaru; Kim, Jong-Nam; Alberti, Claudio; Yona, Sadigurschi; Kim, Jaejoon; Andrade, Maria Teresa; Kalli, Seppo

    2004-05-01

    The MPEG experts are currently developing the MPEG-21 set of standards and this includes a framework and specifications for digital rights management (DRM), delivery of quality of services (QoS) over heterogeneous networks and terminals, packaging of multimedia content and other things essential for the infrastructural aspects of multimedia content distribution. Considerable research effort is being applied to these new developments and the capabilities of MPEG-21 technologies to address specific application areas are being investigated. One such application area is broadcasting, in particular the development of digital TV and its services. In more practical terms, digital TV addresses networking, events, channels, services, programs, signaling, encoding, bandwidth, conditional access, subscription, advertisements and interactivity. MPEG-21 provides an excellent framework of standards to be applied in digital TV applications. Within the scope of this research work we describe a new model based on MPEG-21 and its relevance to digital TV: the digital broadcast item model (DBIM). The goal of the DBIM is to elaborate the potential of MPEG-21 for digital TV applications. Within this paper we focus on a general description of the DBIM, quality of service (QoS) management and metadata filtering, digital rights management and also present use-cases and scenarios where the DBIM"s role is explored in detail.

  19. Basaltic Lava Channels

    NASA Astrophysics Data System (ADS)

    Cashman, K. V.; Griffiths, R. W.; Kerr, R. C.

    2004-12-01

    In Hawaii, the mode of lava transport - through open channels or through insulating lava tubes - determines the thermal, rheological, and emplacement history of a lava flow. Most Hawaiian lavas are erupted at near-liquidus temperatures and are therefore crystal-poor; lava transport through open channels allows rapid cooling and consequent rapid increases in lava crystallinity. Solidified aa flows resulting from channelized flow are typically fine-grained throughout their thickness, indicating cooling of the entire flow thickness during transport. In contrast, transport of lava through insulating tubes permits flow over long distances with little cooling. Flows emerging from such tubes typically have pahoehoe flow surfaces with glassy crusts. Groundmass textures that coarsen from the flow rind to the interior reflect rates of post-emplacement, rather than syn-emplacement, cooling. To distinguish eruption conditions that result in lava channels from those that allow formation of lava tubes, we have performed a series of laboratory experiments involving injection of PEG 600 (a wax with a Newtonian rheology and freezing temperature of 19ºC) into cold water through both uniform and non-uniform sloping channels. In uniform channels, tube formation can be distinguished from open channel flow using a dimensionless parameter based on a solidification time scale, an advection time scale, and a Rayleigh number that describes convection by heat loss from crust-free shear zones. Theoretical analysis predicts that in the open channel regime, the width of the crust (dc) will vary with the channel width (W) as dc = W5/3. Crustal coverage of non-uniform channels in both laboratory experiments and field examples from Kilauea Volcano, Hawaii, is consistent with this prediction. However, experiments in non-uniform channels illustrate additional controls on the surface coverage of lava channels. Most important is crustal extension resulting from flow acceleration through constrictions

  20. T-type Calcium Channel Blockers as Neuroprotective Agents

    PubMed Central

    Kopecky, Benjamin J.; Liang, Ruqiang; Bao, Jianxin

    2014-01-01

    T-type calcium channels are expressed in many diverse tissues, including neuronal, cardiovascular, and endocrine. T-type calcium channels are known to play roles in the development, maintenance, and repair of these tissues but have also been implicated in disease when not properly regulated. Calcium channel blockers have been developed to treat various diseases and their use clinically is widespread due to both their efficacy as well as their safety. Aside from their established clinical applications, recent studies have suggested neuroprotective effects of T-type calcium channels blockers. Many of the current T-type calcium channel blockers could act on other molecular targets besides T-type calcium channels making it uncertain whether their neuroprotective effects are solely due to blocking of T-type calcium channels. In this review, we discuss these drugs as well as newly developed chemical compounds that are designed to be more selective for T-type calcium channels. We review in vitro and in vivo evidence of neuroprotective effects by these T-type calcium channel blockers. We conclude by discussing possible molecular mechanisms underlying neuroprotective effects by T-type calcium channel blockers. PMID:24563219

  1. Parallel digital forensics infrastructure.

    SciTech Connect

    Liebrock, Lorie M.; Duggan, David Patrick

    2009-10-01

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

  2. NLOS single scattering model in digital UV communication

    NASA Astrophysics Data System (ADS)

    Tang, Yi; Wu, Zhong-liang; Ni, Guo-qiang; Tao, Li-qiang

    2008-11-01

    A practical single-scattering model of solar blind UV communication channel, which is suitable for NLOS digital communication is presented in the paper. NLOS transmission loss of UV channel is deduced by Lambert law . Calculation method of scattering phase function and integral of intersection volume between transmitting beam and receiving beam are described detailed in prolate spheriodal coordinate. Base on them, a practicable calculation method about signal to noise ratio (SNR) and bit error rate (BER) of UV communication systems is presented, which construct a bridge between system parameters and digital system performances in simulation of UV communication channel and systems .Under certain BER and typical modulations in UV communication , relationship between system parameters and system performances are discussed.

  3. Millennium Modem/Channelizer Special Test Equipment

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    1995-01-01

    A broadband modem/channelizer test set developed by NASA Lewis Research Center is discussed. The test set is a fully programmable, bit-error-rate (BER) test set designed for broadband modem-only and multichannel demultiplexer/demodulator characterization. It is currently configured for testing a multichannel demultiplexer/demodulator and was developed for the Advanced Research and Projects Agency under a Technology Reinvestment Program Cooperative Agreement entitled 'Millennium: 21st Century Broadband Digital Telecommunications Technology.' The test set can easily be modified to provide testing of other modems and multichannel demultiplexer/demodulator systems and is available to industry for such testing.

  4. Ion channels in microbes

    PubMed Central

    Martinac, Boris; Saimi, Yoshiro; Kung, Ching

    2008-01-01

    Summary Studies of ion channels have for long been dominated by the animalcentric, if not anthropocentric view of physiology. The structures and activities of ion channels had, however, evolved long before the appearance of complex multicellular organisms on Earth. The diversity of ion channels existing in cellular membranes of prokaryotes is a good example. Though at first it may appear as a paradox that most of what we know about the structure of eukaryotic ion channels is based on the structure of bacterial channels, this should not be surprising given the evolutionary relatedness of all living organisms and suitability of microbial cells for structural studies of biological macromolecules in a laboratory environment. Genome sequences of the human as well as various microbial, plant and animal organisms unambiguously established the evolutionary links, whereas crystallographic studies of the structures of major types of ion channels published over the last decade clearly demonstrated the advantage of using microbes as experimental organisms. The purpose of this review is not only to provide an account of acquired knowledge on microbial ion channels but also to show that the study of microbes and their ion channels may also hold a key to solving unresolved molecular mysteries in the future. PMID:18923187

  5. RFI channels, 2

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.

    1981-01-01

    The cutoff parameters for a class of channel models exhibiting burst noise behavior were calculated and the performance of interleaved coding strategies was evaluated. It is concluded that, provided the channel memory is large enough and is properly exploited, interleaved coding is nearly optimal.

  6. Venus - Sinuous Channel

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This full resolution radar mosaic from Magellan at 49 degrees south latitude, 273 degrees east longitude of an area with dimensions of 130 by 190 kilometers (81 by 118 miles), shows a 200 kilometer (124 mile) segment of a sinuous channel on Venus. The channel is approximately 2 kilometers (1.2 miles) wide. These channel-like features are common on the plains of Venus. In some places they appear to have been formed by lava which may have melted or thermally eroded a path over the plains' surface. Most are 1 to 3 kilometers (0.6 to 2 miles) wide. They resemble terrestrial rivers in some respects, with meanders, cutoff oxbows, and abandoned channel segments. However, Venus channels are not as tightly sinuous as terrestrial rivers. Most are partly buried by younger lava plains, making their sources difficult to identify. A few have vast radar-dark plains units associated with them, suggesting large flow volumes. These channels appear to be older than other channel types on Venus, as they are crossed by fractures and wrinkle ridges, and are often buried by other volcanic materials. In addition, they appear to run both upslope and downslope, suggesting that the plains were warped by regional tectonism after channel formation. Resolution of the Magellan data is about 120 meters (400 feet).

  7. Secure quantum signatures using insecure quantum channels

    NASA Astrophysics Data System (ADS)

    Amiri, Ryan; Wallden, Petros; Kent, Adrian; Andersson, Erika

    2016-03-01

    Digital signatures are widely used in modern communication to guarantee authenticity and transferability of messages. The security of currently used classical schemes relies on computational assumptions. We present a quantum signature scheme that does not require trusted quantum channels. We prove that it is unconditionally secure against the most general coherent attacks, and show that it requires the transmission of significantly fewer quantum states than previous schemes. We also show that the quantum channel noise threshold for our scheme is less strict than for distilling a secure key using quantum key distribution. This shows that "direct" quantum signature schemes can be preferable to signature schemes relying on secret shared keys generated using quantum key distribution.

  8. Digital biology and chemistry.

    PubMed

    Witters, Daan; Sun, Bing; Begolo, Stefano; Rodriguez-Manzano, Jesus; Robles, Whitney; Ismagilov, Rustem F

    2014-09-01

    This account examines developments in "digital" biology and chemistry within the context of microfluidics, from a personal perspective. Using microfluidics as a frame of reference, we identify two areas of research within digital biology and chemistry that are of special interest: (i) the study of systems that switch between discrete states in response to changes in chemical concentration of signals, and (ii) the study of single biological entities such as molecules or cells. In particular, microfluidics accelerates analysis of switching systems (i.e., those that exhibit a sharp change in output over a narrow range of input) by enabling monitoring of multiple reactions in parallel over a range of concentrations of signals. Conversely, such switching systems can be used to create new kinds of microfluidic detection systems that provide "analog-to-digital" signal conversion and logic. Microfluidic compartmentalization technologies for studying and isolating single entities can be used to reconstruct and understand cellular processes, study interactions between single biological entities, and examine the intrinsic heterogeneity of populations of molecules, cells, or organisms. Furthermore, compartmentalization of single cells or molecules in "digital" microfluidic experiments can induce switching in a range of reaction systems to enable sensitive detection of cells or biomolecules, such as with digital ELISA or digital PCR. This "digitizing" offers advantages in terms of robustness, assay design, and simplicity because quantitative information can be obtained with qualitative measurements. While digital formats have been shown to improve the robustness of existing chemistries, we anticipate that in the future they will enable new chemistries to be used for quantitative measurements, and that digital biology and chemistry will continue to provide further opportunities for measuring biomolecules, understanding natural systems more deeply, and advancing molecular and

  9. Athermalized channeled spectropolarimeter enhancement.

    SciTech Connect

    Jones, Julia Craven; Way, Brandyn Michael; Mercier, Jeffrey Alan; Hunt, Jeffery P.

    2013-09-01

    Channeled spectropolarimetry can measure the complete polarization state of light as a function of wavelength. Typically, a channeled spectropolarimeter uses high order retarders made of uniaxial crystal to amplitude modulate the measured spectrum with the spectrally-dependent Stokes polarization information. A primary limitation of conventional channeled spectropolarimeters is related to the thermal variability of the retarders. Thermal variation often forces frequent system recalibration, particularly for field deployed systems. However, implementing thermally stable retarders, made of biaxial crystal, results in an athermal channeled spectropolarimeter that relieves the need for frequent recalibration. This report presents experimental results for an anthermalized channeled spectropolarimeter prototype produced using potassium titanyl phosphate. The results of this prototype are compared to the current thermal stabilization state of the art. Finally, the application of the technique to the thermal infrared is studied, and the athermalization concept is applied to an infrared imaging spectropolarimeter design.

  10. Generalized channeled polarimetry.

    PubMed

    Alenin, Andrey S; Tyo, J Scott

    2014-05-01

    Channeled polarimeters measure polarization by modulating the measured intensity in order to create polarization-dependent channels that can be demodulated to reveal the desired polarization information. A number of channeled systems have been described in the past, but their proposed designs often unintentionally sacrifice optimality for ease of algebraic reconstruction. To obtain more optimal systems, a generalized treatment of channeled polarimeters is required. This paper describes methods that enable handling of multi-domain modulations and reconstruction of polarization information using linear algebra. We make practical choices regarding use of either Fourier or direct channels to make these methods more immediately useful. Employing the introduced concepts to optimize existing systems often results in superficial system changes, like changing the order, orientation, thickness, or spacing of polarization elements. For the two examples we consider, we were able to reduce noise in the reconstruction to 34.1% and 57.9% of the original design values. PMID:24979633

  11. Jamming in Vertical Channels

    NASA Astrophysics Data System (ADS)

    Baxter, G. William; McCausland, Jeffrey; Steel, Fiona

    2010-03-01

    We experimentally study jamming of cylindrical grains in a vertical channel. The grains have a low aspect-ratio (height/diameter < 1) so their shape is like antacid tablets or poker chips. They are allowed to fall through a vertical channel with a square cross section. The channel width is greater than the diameter of a grain and constant throughout the length of the channel with no obstructions or constrictions. It is observed that grains sometimes jam in this apparatus. In a jam, grains form a stable structure from one side of the channel to the other with nothing beneath them. Jams may be strong enough to support additional grains above. The probability of a jam occurring is a function of the grain height and diameter. We will present experimental measurements of the jamming probability in this system and discuss the relationship of these results to other experiments and theories.

  12. The Clinically Tested Gardos Channel Inhibitor Senicapoc Exhibits Antimalarial Activity

    PubMed Central

    Tubman, Venée N.; Mejia, Pedro; Shmukler, Boris E.; Bei, Amy K.; Alper, Seth L.; Mitchell, James R.

    2015-01-01

    Senicapoc, a Gardos channel inhibitor, prevented erythrocyte dehydration in clinical trials of patients with sickle cell disease. We tested the hypothesis that senicapoc-induced blockade of the Gardos channel inhibits Plasmodium growth. Senicapoc inhibited in vitro growth of human and primate plasmodia during the clinical blood stage. Senicapoc treatment suppressed P. yoelii parasitemia in vivo in C57BL/6 mice. The reassuring safety and biochemical profile of senicapoc encourage its use in antimalarial development. PMID:26459896

  13. From Digital Divide to Digital Democracy.

    ERIC Educational Resources Information Center

    de los Santos, Gerardo E., Ed.; de los Santos, Alfredo G., Jr., Ed.; Milliron, Mark David, Ed.

    This publication is one of many efforts of the League for Innovation in the Community College to address the issue of societal technology access and learning needs. This work addresses the issue of the digital divide, which includes the often conflicting perspectives of information technology (IT) access and literacy needs held by government…

  14. The Digital Carrot, the Digital Stick

    ERIC Educational Resources Information Center

    Jackson, Gregory A.

    2007-01-01

    In this article, the author asserts that technology is not the answer to digital piracy at colleges and universities. Citing the three most common explanations given for copyright infringement--that students cannot always get what they want, cannot always use what they can get, or think the price of what they can get is unfair--he asserts that the…

  15. Digital Booktalk: Digital Media for Reluctant Readers

    ERIC Educational Resources Information Center

    Gunter, Glenda; Kenny, Robert

    2008-01-01

    New learning and communications paradigms of today's learners are extending the definition of literacy and directly affecting how reading and writing skills are acquired (Leu, 2000). Mirroring an ever-expanding definition of literacy, new college and K-12 curricular programs that redefine digital media are popping up all over the country. Story is…

  16. Computing Logarithms Digit-by-Digit

    ERIC Educational Resources Information Center

    Goldberg, Mayer

    2005-01-01

    In this work, we present an algorithm for computing logarithms of positive real numbers, that bears structural resemblance to the elementary school algorithm of long division. Using this algorithm, we can compute successive digits of a logarithm using a 4-operation pocket calculator. The algorithm makes no use of Taylor series or calculus, but…

  17. Superconductive digital readout for IR FPA sensors

    NASA Astrophysics Data System (ADS)

    Durand, D. J.; Abelson, L. A.; Dalrymple, B. J.; Eaton, L.; Heflinger, L. O.; Leung, M.; Pham, T.; Sandell, R. D.; Silver, A. H.; Spargo, J. W.

    1992-07-01

    We have built and demonstrated an all superconductive digital readout for use in an IR focal plane array sensor. High performance, ultralow power superconductive circuits perform the functions of low noise preamplification and analog to digital conversion. The superconductive readout was tested with a variety of detectors, including InSb, Si:As, and a thin film NbN superconducting detector. Light sources included a HeNe laser (0.6 micron), a CO2 laser (10 microns), and a blackbody (400 to 900 K). In each case, the detector and readout circuitry was assembled into a 2 inch diameter, 6 inch long test package cooled in a single dewar. We demonstrated the functionality of the detector/readout channel from input photons to output digital signal. The superconductive readout reported here used Nb-based circuits operating at 4 K. An NbN squid amplifier and detector have subsequently been demonstrated above 10 K. We discuss the extension of the entire digital readout to operating temperatures above 10 K.

  18. Safety and Liability.

    ERIC Educational Resources Information Center

    Berthelot, Ronald J.; And Others

    1982-01-01

    This series of five articles highlights Pensacola Junior College's occupational safety course, involving simulated emergencies, Florida's standards for teacher liability, electrical safety in the classroom and laboratory, color coding for machine safety, and Florida industrial arts safety instructional materials. (SK)

  19. Digital stain separation for histological images.

    PubMed

    Tadrous, P J

    2010-11-01

    It is often desirable to perform digital image analyses on sections prepared for human interpretation, e.g. nuclear chromatin texture analysis or three-dimensional reconstructions using sections requiring human delineation of structures of interest. Unfortunately such analyses are often more effective using stains with less complex contrast. Here an automated selective 'de-staining' method for digital images is presented. The method separates an image into its red, green and blue and hue, saturation and intensity components. A mask of stained tissue is prepared by automatic percentile thresholding. A single weighted inverted colour channel is then added to each of the three primary colour channels separately by an iterative algorithm that adjusts the weights to give minimum variance within the mask. The modified red, green and blue channels are then recombined. This method is automatic requiring no pre-definition of stain colours or special hardware. The method is demonstrated to 'de-stain' nuclei in haematoxylin and eosin (H&E) sections (and a separate haematoxylin image can be derived from this). An image of isolated brown reaction product is produced with immunoperoxidase preparations counterstained with haematoxylin. Furthermore trichrome (haematoxylin van Gieson, picrosirius red) and other common stains may be separated into their components with modifications of the same algorithm. Although other methods for colour separation do exist (e.g. spectral pathology and colour deconvolution) these require special apparatus or precise calibration and foreknowledge of pure dye colour spectra. The present method of digital stain separation is fully automatic with no such prerequisites. PMID:20946383

  20. 47 CFR 80.359 - Frequencies for digital selective calling (DSC).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Frequencies for digital selective calling (DSC). 80.359 Section 80.359 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Frequencies Radiotelegraphy § 80.359 Frequencies for digital selective calling (DSC)....