Digital scrambling for shuttle communication links: Do drawbacks outweigh advantages?

NASA Technical Reports Server (NTRS)

Dessouky, K.

1985-01-01

Digital data scrambling has been considered for communication systems using NRZ (non-return to zero) symbol formats. The purpose is to increase the number of transitions in the data to improve the performance of the symbol synchronizer. This is accomplished without expanding the bandwidth but at the expense of increasing the data bit error rate (BER). Models for the scramblers/descramblers of practical interest are presented together with the appropriate link model. The effects of scrambling on the performance of coded and uncoded links are studied. The results are illustrated by application to the Tracking and Data Relay Satellite System links. Conclusions regarding the usefulness of scrambling are also given.

Wechsler Adult Intelligence Scale-Third Edition short form for index and IQ scores in a psychiatric population.

PubMed

Christensen, Bruce K; Girard, Todd A; Bagby, R Michael

2007-06-01

An eight-subtest short form (SF8) of the Wechsler Adult Intelligence Scale, Third Edition (WAIS-III), maintaining equal representation of each index factor, was developed for use with psychiatric populations. Data were collected from a mixed inpatient/outpatient sample (99 men and 101 women) referred for neuropsychological assessment. Psychometric analyses revealed an optimal SF8 comprising Vocabulary, Similarities, Arithmetic, Digit Span, Picture Completion, Matrix Reasoning, Digit Symbol Coding, and Symbol Search, scored by linear scaling. Expanding on previous short forms, the current SF8 maximizes the breadth of information and reduces administration time while maintaining the original WAIS-III factor structure. (c) 2007 APA, all rights reserved

Digital Data Matrix Scanner Developnent At Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

2004-01-01

Research at NASA's Marshall Space Flight Center has resulted in a system for reading hidden identification codes using a hand-held magnetic scanner. It's an invention that could help businesses improve inventory management, enhance safety, improve security, and aid in recall efforts if defects are discovered. Two-dimensional Data Matrix symbols consisting of letters and numbers permanently etched on items for identification and resembling a small checkerboard pattern are more efficient and reliable than traditional bar codes, and can store up to 100 times more information. A team led by Fred Schramm of the Marshall Center's Technology Transfer Department, in partnership with PRI,Torrance, California, has developed a hand-held device that can read this special type of coded symbols, even if covered by up to six layers of paint. Before this new technology was available, matrix symbols were read with optical scanners, and only if the codes were visible. This latest improvement in digital Data Matrix technologies offers greater flexibility for businesses and industries already using the marking system. Paint, inks, and pastes containing magnetic properties are applied in matrix symbol patterns to objects with two-dimensional codes, and the codes are read by a magnetic scanner, even after being covered with paint or other coatings. The ability to read hidden matrix symbols promises a wide range of benefits in a number of fields, including airlines, electronics, healthcare, and the automotive industry. Many industries would like to hide information on a part, so it can be read only by the party who put it there. For instance, the automotive industry uses direct parts marking for inventory control, but for aesthetic purposes the marks often need to be invisible. Symbols have been applied to a variety of materials, including metal, plastic, glass, paper, fabric and foam, on everything from electronic parts to pharmaceuticals to livestock. The portability of the hand-held scanner makes work faster and easier. It reads marks in darkness, under bright light that might interfere with optical reading of visible marks, and can detect symbols obscured by discoloration or contamination. Through a license with NASA, another partner, Robotic Vision Systems, Inc., of Nashua, New Hampshire, will sell the scanner on the commercial market. NASA continues to seek additional companies to license the product. Joint efforts by Marshall researchers and industry partners are aimed at improving dentification technology as part of NASA's program to better life on Earth through technology designed for the space program. In this photo, Don Roxby, Robotic Vision Systems, Inc., (left)demonstrates the magnetic handheld scanner for Fred Schramm, (Right) MSFC Technology Transfer Department.

Epidemiological Study of Mild Traumatic Brain Injury Sequelae Caused by Blast Exposure During Operations Iraq Freedom and Enduring Freedom

DTIC Science & Technology

2011-10-01

working memory),(Vanderploeg et al., 2005) Wechsler Adult Intelligence Scale III (WAIS-III) items: Digit Symbol Coding, Digit Span, Letter-Number...EFFORT William C. Walker, MD, Principal Investigator September, 2008 20 (see: VCU sub-award) David X. Cifu, MD Co-Investigator September, 2008...group for our purposes. The neuropsychological battery will consist of the following standardized, validated, tests of proven reliability: Wechsler Test

WISC-III cognitive profiles in children with developmental dyslexia: specific cognitive disability and diagnostic utility.

PubMed

Moura, Octávio; Simões, Mário R; Pereira, Marcelino

2014-02-01

This study analysed the usefulness of the Wechsler Intelligence Scale for Children-Third Edition in identifying specific cognitive impairments that are linked to developmental dyslexia (DD) and the diagnostic utility of the most common profiles in a sample of 100 Portuguese children (50 dyslexic and 50 normal readers) between the ages of 8 and 12 years. Children with DD exhibited significantly lower scores in the Verbal Comprehension Index (except the Vocabulary subtest), Freedom from Distractibility Index (FDI) and Processing Speed Index subtests, with larger effect sizes than normal readers in Information, Arithmetic and Digit Span. The Verbal-Performance IQs discrepancies, Bannatyne pattern and the presence of FDI; Arithmetic, Coding, Information and Digit Span subtests (ACID) and Symbol Search, Coding, Arithmetic and Digit Span subtests (SCAD) profiles (full or partial) in the lowest subtests revealed a low diagnostic utility. However, the receiver operating characteristic curve and the optimal cut-off score analyses of the composite ACID; FDI and SCAD profiles scores showed moderate accuracy in correctly discriminating dyslexic readers from normal ones. These results suggested that in the context of a comprehensive assessment, the Wechsler Intelligence Scale for Children-Third Edition provides some useful information about the presence of specific cognitive disabilities in DD. Practitioner Points. Children with developmental dyslexia revealed significant deficits in the Wechsler Intelligence Scale for Children-Third Edition subtests that rely on verbal abilities, processing speed and working memory. The composite Arithmetic, Coding, Information and Digit Span subtests (ACID); Freedom from Distractibility Index and Symbol Search, Coding, Arithmetic and Digit Span subtests (SCAD) profile scores showed moderate accuracy in correctly discriminating dyslexics from normal readers. Wechsler Intelligence Scale for Children-Third Edition may provide some useful information about the presence of specific cognitive disabilities in developmental dyslexia. Copyright © 2013 John Wiley & Sons, Ltd.

PPM Receiver Implemented in Software

NASA Technical Reports Server (NTRS)

Gray, Andrew; Kang, Edward; Lay, Norman; Vilnrotter, Victor; Srinivasan, Meera; Lee, Clement

2010-01-01

A computer program has been written as a tool for developing optical pulse-position- modulation (PPM) receivers in which photodetector outputs are fed to analog-to-digital converters (ADCs) and all subsequent signal processing is performed digitally. The program can be used, for example, to simulate an all-digital version of the PPM receiver described in Parallel Processing of Broad-Band PPM Signals (NPO-40711), which appears elsewhere in this issue of NASA Tech Briefs. The program can also be translated into a design for digital PPM receiver hardware. The most notable innovation embodied in the software and the underlying PPM-reception concept is a digital processing subsystem that performs synchronization of PPM time slots, even though the digital processing is, itself, asynchronous in the sense that no attempt is made to synchronize it with the incoming optical signal a priori and there is no feedback to analog signal processing subsystems or ADCs. Functions performed by the software receiver include time-slot synchronization, symbol synchronization, coding preprocessing, and diagnostic functions. The program is written in the MATLAB and Simulink software system. The software receiver is highly parameterized and, hence, programmable: for example, slot- and symbol-synchronization filters have programmable bandwidths.

Digital Communications in Spatially Distributed Interference Channels.

DTIC Science & Technology

1982-12-01

July 1980 through 31 March 1981. This report is organized into five parts. Part I describes an optimum recivr tructure fordgtlcmutatnI ~ tal itiue (over...Jelinek, and J. Raviv , "Optimal Decoding of Linear Codes for Minimizing Symbol Error Rate", IEEE Trans. Inform. Theory, Vol. IT-20, pp. 284-287, March 1974

An implementation of a reference symbol approach to generic modulation in fading channels

NASA Technical Reports Server (NTRS)

Young, R. J.; Lodge, J. H.; Pacola, L. C.

1990-01-01

As mobile satellite communications systems evolve over the next decade, they will have to adapt to a changing tradeoff between bandwidth and power. This paper presents a flexible approach to digital modulation and coding that will accommodate both wideband and narrowband schemes. This architecture could be the basis for a family of modems, each satisfying a specific power and bandwidth constraint, yet all having a large number of common signal processing blocks. The implementation of this generic approach, with general purpose digital processors for transmission of 4.8 kilobits per sec. digitally encoded speech, is described.

Comparisons of mental clocks.

PubMed

Paivio, A

1978-02-01

Subjects in three experiments were presented with pairs of clock times and were required to choose the one in which the hour and minute hand formed the smaller angle. In Experiments 1 and 2, the times were presented digitally, necessitating a transformation into symbolic representations from which the angular size difference could be inferred. The results revealed orderly symbolic distance effects so that comparison reaction time increased as the angular size difference decreased. Moreover, subjects generally reported using imagery to make the judgment, and subjects scoring high on test of imagery ability were faster than those scoring low on such tests. Experiment 3 added a direct perceptual condition in which subjects compared angles between pairs of hands on two drawn (analog) clocks, as well as a mixed condition involving one digital and one analog clock time. The results showed comparable distance effects for all conditions. In addition, reaction time increased from the perceptual, to the mixed, to the pure-digital condition. These results are consistent with predictions from an image-based dual-coding theory.

Quantity processing in deaf and hard of hearing children: evidence from symbolic and nonsymbolic comparison tasks.

PubMed

Rodríguez-Santos, José Miguel; Calleja, Marina; García-Orza, Javier; Iza, Mauricio; Damas, Jesús

2014-01-01

Deaf children usually achieve lower scores on numerical tasks than normally hearing peers. Explanations for mathematical disabilities in hearing children are based on quantity representation deficits (Geary, 1994) or on deficits in accessing these representations (Rousselle & Noël, 2008). The present study aimed to verify, by means of symbolic (Arabic digits) and nonsymbolic (dot constellations and hands) magnitude comparison tasks, whether deaf children show deficits in representations or in accessing numerical representations. The study participants were 10 prelocutive deaf children and 10 normally hearing children. Numerical distance and magnitude were manipulated. Response time (RT) analysis showed similar magnitude and distance effects in both groups on the 3 tasks. However, slower RTs were observed among the deaf participants on the symbolic task alone. These results suggest that although both groups' quantity representations were similar, the deaf group experienced a delay in accessing representations from symbolic codes.

Depth Of Modulation And Spot Size Selection In Bar-Code Laser Scanners

NASA Astrophysics Data System (ADS)

Barkan, Eric; Swartz, Jerome

1982-04-01

Many optical and electronic considerations enter into the selection of optical spot size in flying spot laser scanners of the type used in modern industrial and commerical environments. These include: the scale of the symbols to be read, optical background noise present in the symbol substrate, and factors relating to the characteristics of the signal processor. Many 'front ends' consist of a linear signal conditioner followed by nonlinear conditioning and digitizing circuitry. Although the nonlinear portions of the circuit can be difficult to characterize mathematically, it is frequently possible to at least give a minimum depth of modulation measure to yield a worst-case guarantee of adequate performance with respect to digitization accuracy. Depth of modulation actually delivered to the nonlinear circuitry will depend on scale, contrast, and noise content of the scanned symbol, as well as the characteristics of the linear conditioning circuitry (eg. transfer function and electronic noise). Time and frequency domain techniques are applied in order to estimate the effects of these factors in selecting a spot size for a given system environment. Results obtained include estimates of the effects of the linear front end transfer function on effective spot size and asymmetries which can affect digitization accuracy. Plots of convolution-computed modulation patterns and other important system properties are presented. Considerations are limited primarily to Gaussian spot profiles but also apply to more general cases. Attention is paid to realistic symbol models and to implications with respect to printing tolerances.

Discrepancy of performance among working memory-related tasks in autism spectrum disorders was caused by task characteristics, apart from working memory, which could interfere with task execution.

PubMed

Nakahachi, Takayuki; Iwase, Masao; Takahashi, Hidetoshi; Honaga, Eiko; Sekiyama, Ryuji; Ukai, Satoshi; Ishii, Ryouhei; Ishigami, Wataru; Kajimoto, Osami; Yamashita, Ko; Hashimoto, Ryota; Tanii, Hisashi; Shimizu, Akira; Takeda, Masatoshi

2006-06-01

Working memory performance has been inconsistently reported in autism spectrum disorders (ASD). Several studies in ASD have found normal performance in digit span and poor performance in digit symbol task although these are closely related with working memory. It is assumed that poor performance in digit symbol could be explained by confirmatory behavior, which is induced due to the vague memory representation of number-symbol association. Therefore it was hypothesized that the performance of working memory task, in which vagueness did not cause confirmatory behavior, would be normal in ASD. For this purpose, the Advanced Trail Making Test (ATMT) was used. The performance of digit span, digit symbol and ATMT was compared between ASD and normal control. The digit span, digit symbol and ATMT was given to 16 ASD subjects and 28 IQ-, age- and sex-matched control subjects. The scores of these tasks were compared. A significantly lower score for ASD was found only in digit symbol compared with control subjects. There were no significant difference in digit span and working memory estimated by ATMT. Discrepancy of scores among working memory-related tasks was demonstrated in ASD. Poor digit symbol performance, normal digit span and normal working memory in ATMT implied that ASD subjects would be intact in working memory itself, and that superficial working memory dysfunction might be observed due to confirmatory behavior in digit symbol. Therefore, to evaluate working memory in ASD, tasks that could stimulate psychopathology specific to ASD should be avoided.

Neural foundations and functional specificity of number representations.

PubMed

Piazza, Manuela; Eger, Evelyn

2016-03-01

Number is a complex category, as with the word "number" we may refer to different entities. First, it is a perceptual property that characterizes any set of individual items, namely its cardinality. The ability to extract the (approximate) cardinality of sets is almost universal in the animal domain and present in humans since birth. In primates, posterior parietal cortex seems to be a crucial site for this ability, even if the degree of selectivity of numerical representations in parietal cortex reported to date appears much lower compared to that of other semantic categories in the ventral stream. Number can also be intended as a mathematical object, which we humans use to count, measure, and order: a (verbal or visual) symbol that stands for the cardinality of a set, the intensity of a continuous quantity or the position of an item on a list. Evidence points to a convergence towards parietal cortex for the semantic coding of numerical symbols and to the bilateral occipitotemporal cortex for the shape coding of Arabic digits and other number symbols. Copyright © 2015 Elsevier Ltd. All rights reserved.

Numerical analysis of stiffened shells of revolution. Volume 4: Engineer's program manual for STARS-2S shell theory automated for rotational structures - 2 (statics) digital computer program

NASA Technical Reports Server (NTRS)

Svalbonas, V.; Ogilvie, P.

1973-01-01

The engineering programming information for the digital computer program for analyzing shell structures is presented. The program is designed to permit small changes such as altering the geometry or a table size to fit the specific requirements. Each major subroutine is discussed and the following subjects are included: (1) subroutine description, (2) pertinent engineering symbols and the FORTRAN coded counterparts, (3) subroutine flow chart, and (4) subroutine FORTRAN listing.

An 8-PSK TDMA uplink modulation and coding system

NASA Technical Reports Server (NTRS)

Ames, S. A.

1992-01-01

The combination of 8-phase shift keying (8PSK) modulation and greater than 2 bits/sec/Hz drove the design of the Nyquist filter to one specified to have a rolloff factor of 0.2. This filter when built and tested was found to produce too much intersymbol interference and was abandoned for a design with a rolloff factor of 0.4. The preamble is limited to 100 bit periods of the uncoded bit period of 5 ns for a maximum preamble length of 500 ns or 40 8PSK symbol times at 12.5 ns per symbol. For 8PSK modulation, the required maximum degradation of 1 dB in -20 dB cochannel interference (CCI) drove the requirement for forward error correction coding. In this contract, the funding was not sufficient to develop the proposed codec so the codec was limited to a paper design during the preliminary design phase. The mechanization of the demodulator is digital, starting from the output of the analog to digital converters which quantize the outputs of the quadrature phase detectors. This approach is amenable to an application specific integrated circuit (ASIC) replacement in the next phase of development.

Benefit from NASA

NASA Image and Video Library

2004-01-08

Research at NASA's Marshall Space Flight Center has resulted in a system for reading hidden identification codes using a hand-held magnetic scanner. It's an invention that could help businesses improve inventory management, enhance safety, improve security, and aid in recall efforts if defects are discovered. Two-dimensional Data Matrix symbols consisting of letters and numbers permanently etched on items for identification and resembling a small checkerboard pattern are more efficient and reliable than traditional bar codes, and can store up to 100 times more information. A team led by Fred Schramm of the Marshall Center's Technology Transfer Department, in partnership with PRI,Torrance, California, has developed a hand-held device that can read this special type of coded symbols, even if covered by up to six layers of paint. Before this new technology was available, matrix symbols were read with optical scanners, and only if the codes were visible. This latest improvement in digital Data Matrix technologies offers greater flexibility for businesses and industries already using the marking system. Paint, inks, and pastes containing magnetic properties are applied in matrix symbol patterns to objects with two-dimensional codes, and the codes are read by a magnetic scanner, even after being covered with paint or other coatings. The ability to read hidden matrix symbols promises a wide range of benefits in a number of fields, including airlines, electronics, healthcare, and the automotive industry. Many industries would like to hide information on a part, so it can be read only by the party who put it there. For instance, the automotive industry uses direct parts marking for inventory control, but for aesthetic purposes the marks often need to be invisible. Symbols have been applied to a variety of materials, including metal, plastic, glass, paper, fabric and foam, on everything from electronic parts to pharmaceuticals to livestock. The portability of the hand-held scanner makes work faster and easier. It reads marks in darkness, under bright light that might interfere with optical reading of visible marks, and can detect symbols obscured by discoloration or contamination. Through a license with NASA, another partner, Robotic Vision Systems, Inc., of Nashua, New Hampshire, will sell the scanner on the commercial market. NASA continues to seek additional companies to license the product. Joint efforts by Marshall researchers and industry partners are aimed at improving dentification technology as part of NASA's program to better life on Earth through technology designed for the space program. In this photo, Don Roxby, Robotic Vision Systems, Inc., (left)demonstrates the magnetic handheld scanner for Fred Schramm, (Right) MSFC Technology Transfer Department.

The role of visual spatial attention in adult developmental dyslexia.

PubMed

Collis, Nathan L; Kohnen, Saskia; Kinoshita, Sachiko

2013-01-01

The present study investigated the nature of visual spatial attention deficits in adults with developmental dyslexia, using a partial report task with five-letter, digit, and symbol strings. Participants responded by a manual key press to one of nine alternatives, which included other characters in the string, allowing an assessment of position errors as well as intrusion errors. The results showed that the dyslexic adults performed significantly worse than age-matched controls with letter and digit strings but not with symbol strings. Both groups produced W-shaped serial position functions with letter and digit strings. The dyslexics' deficits with letter string stimuli were limited to position errors, specifically at the string-interior positions 2 and 4. These errors correlated with letter transposition reading errors (e.g., reading slat as "salt"), but not with the Rapid Automatized Naming (RAN) task. Overall, these results suggest that the dyslexic adults have a visual spatial attention deficit; however, the deficit does not reflect a reduced span in visual-spatial attention, but a deficit in processing a string of letters in parallel, probably due to difficulty in the coding of letter position.

Digit Symbol Performance in Mild Dementia and Depression.

ERIC Educational Resources Information Center

Hart, Robert P.; And Others

1987-01-01

Patients with mild dementia of the Alzheimer's type (DAT), patients with major depression, and normal control subjects completed the Wechsler Adult Intelligence Scale (WAIS) Digit Symbol test of incidental memory. Though mild DAT and depressed patients had equivalent deficits in psychomotor speed, DAT patients recalled fewer digit-symbol items.…

Description of 3D digital curves using the theory free groups

NASA Astrophysics Data System (ADS)

Imiya, Atsushi; Oosawa, Muneaki

1999-09-01

In this paper, we propose a new descriptor for two- and three- dimensional digital curves using the theory of free groups. A spatial digital curve is expressed as a word which is an element of the free group which consists from three elements. These three symbols correspond to the directions of the orthogonal coordinates, respectively. Since a digital curve is treated as a word which is a sequence of alphabetical symbols, this expression permits us to describe any geometric operation as rewriting rules for words. Furthermore, the symbolic derivative of words yields geometric invariants of digital curves for digital Euclidean motion. These invariants enable us to design algorithms for the matching and searching procedures of partial structures of digital curves. Moreover, these symbolic descriptors define the global and local distances for digital curves as an editing distance.

Incidental recall on WAIS-R digit symbol discriminates Alzheimer's and Parkinson's diseases.

PubMed

Demakis, G J; Sawyer, T P; Fritz, D; Sweet, J J

2001-03-01

The purpose of this study was to examine how Alzheimer's (n = 37) and Parkinson's (n = 21) patients perform on the incidental recall adaptation to the Digit Symbol of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) and how such performance is related to established cognitive efficiency and memory measures. This adaptation requires the examinee to complete the entire subtest and then, without warning, to immediately recall the symbols associated with each number. Groups did not differ significantly on standard Digit Symbol administration (90 seconds), but on recall Parkinson's patients recalled significantly more symbols and symbol-number pairs than Alzheimer's patients. Using only the number of symbols recalled, discriminate function analysis correctly classified 76% of these patients. Correlations between age-corrected scaled score, symbols incidentally recalled, and established measures of cognitive efficiency and memory provided evidence of convergent and divergent validity. Age-corrected scaled scores were more consistently and strongly related to cognitive efficiency, whereas symbols recalled were more consistently and strongly related to memory measures. These findings suggest that the Digit Symbol recall adaptation is actually assessing memory and that it can be another useful way to detect memory impairment. Copyright 2001 John Wiley & Sons, Inc.

Prioritized LT Codes

NASA Technical Reports Server (NTRS)

Woo, Simon S.; Cheng, Michael K.

2011-01-01

The original Luby Transform (LT) coding scheme is extended to account for data transmissions where some information symbols in a message block are more important than others. Prioritized LT codes provide unequal error protection (UEP) of data on an erasure channel by modifying the original LT encoder. The prioritized algorithm improves high-priority data protection without penalizing low-priority data recovery. Moreover, low-latency decoding is also obtained for high-priority data due to fast encoding. Prioritized LT codes only require a slight change in the original encoding algorithm, and no changes at all at the decoder. Hence, with a small complexity increase in the LT encoder, an improved UEP and low-decoding latency performance for high-priority data can be achieved. LT encoding partitions a data stream into fixed-sized message blocks each with a constant number of information symbols. To generate a code symbol from the information symbols in a message, the Robust-Soliton probability distribution is first applied in order to determine the number of information symbols to be used to compute the code symbol. Then, the specific information symbols are chosen uniform randomly from the message block. Finally, the selected information symbols are XORed to form the code symbol. The Prioritized LT code construction includes an additional restriction that code symbols formed by a relatively small number of XORed information symbols select some of these information symbols from the pool of high-priority data. Once high-priority data are fully covered, encoding continues with the conventional LT approach where code symbols are generated by selecting information symbols from the entire message block including all different priorities. Therefore, if code symbols derived from high-priority data experience an unusual high number of erasures, Prioritized LT codes can still reliably recover both high- and low-priority data. This hybrid approach decides not only "how to encode" but also "what to encode" to achieve UEP. Another advantage of the priority encoding process is that the majority of high-priority data can be decoded sooner since only a small number of code symbols are required to reconstruct high-priority data. This approach increases the likelihood that high-priority data is decoded first over low-priority data. The Prioritized LT code scheme achieves an improvement in high-priority data decoding performance as well as overall information recovery without penalizing the decoding of low-priority data, assuming high-priority data is no more than half of a message block. The cost is in the additional complexity required in the encoder. If extra computation resource is available at the transmitter, image, voice, and video transmission quality in terrestrial and space communications can benefit from accurate use of redundancy in protecting data with varying priorities.

Adults' Arithmetic Builds on Fast and Automatic Processing of Arabic Digits: Evidence from an Audiovisual Matching Paradigm

PubMed Central

Sasanguie, Delphine; Reynvoet, Bert

2014-01-01

Several studies have shown that performance on symbolic number tasks is related to individual differences in arithmetic. However, it is not clear which process is responsible for this association, i.e. fast, automatic processing of symbols per se or access to the underlying non-symbolic representation of the symbols. To dissociate between both options, adult participants performed an audiovisual matching paradigm. Auditory presented number words needed to be matched with either Arabic digits or dot patterns. The results revealed that a distance effect was present in the dots-number word matching task and absent in the digit-number word matching task. Crucially, only performance in the digit task contributed to the variance in arithmetical abilities. This led us to conclude that adults' arithmetic builds on the ability to quickly and automatically process Arabic digits, without the underlying non-symbolic magnitude representation being activated. PMID:24505308

Sensitivity and specificity of a digit symbol recognition trial in the identification of response bias.

PubMed

Kim, Nancy; Boone, Kyle B; Victor, Tara; Lu, Po; Keatinge, Carolyn; Mitchell, Cary

2010-08-01

Recently published practice standards recommend that multiple effort indicators be interspersed throughout neuropsychological evaluations to assess for response bias, which is most efficiently accomplished through use of effort indicators from standard cognitive tests already included in test batteries. The present study examined the utility of a timed recognition trial added to standard administration of the WAIS-III Digit Symbol subtest in a large sample of "real world" noncredible patients (n=82) as compared with credible neuropsychology clinic patients (n=89). Scores from the recognition trial were more sensitive in identifying poor effort than were standard Digit Symbol scores, and use of an equation incorporating Digit Symbol Age-Corrected Scaled Scores plus accuracy and time scores from the recognition trial was associated with nearly 80% sensitivity at 88.7% specificity. Thus, inclusion of a brief recognition trial to Digit Symbol administration has the potential to provide accurate assessment of response bias.

Advanced technology satellite demodulator development

NASA Technical Reports Server (NTRS)

Ames, Stephen A.

1989-01-01

Ford Aerospace has developed a proof-of-concept satellite 8 phase shift keying (PSK) modulation and coding system operating in the Time Division Multiple Access (TDMA) mode at a data range of 200 Mbps using rate 5/6 forward error correction coding. The 80 Msps 8 PSK modem was developed in a mostly digital form and is amenable to an ASIC realization in the next phase of development. The codec was developed as a paper design only. The power efficiency goal was to be within 2 dB of theoretical at a bit error rate (BER) of 5x10(exp 7) while the measured implementation loss was 4.5 dB. The bandwidth efficiency goal was 2 bits/sec/Hz while the realized bandwidth efficiency was 1.8 bits/sec/Hz. The burst format used a preamble of only 40 8 PSK symbol times including 32 symbols of all zeros and an eight symbol unique word. The modem and associated special test equipment (STE) were fabricated mostly on a specially designed stitch-weld board although a few of the highest rate circuits were built on printed circuit cards. All the digital circuits were ECL to support the clock rates of from 80 MHz to 360 MHz. The transmitter and receiver matched filters were square-root Nyquist bandpass filters realized at the 3.37 GHz i.f. The modem operated as a coherent system although no analog phase locked (PLL) loop was employed. Within the budgetary constraints of the program, the approach to the demodulator has been proven and is eligible to proceed to the next phase of development of a satellite demodulator engineering model. This would entail the development of an ASIC version of the digital portion of the demodulator, and MMIC version of the quadrature detector, and SAW Nyquist filters to realize the bandwidth efficiency.

Exploiting the cannibalistic traits of Reed-Solomon codes

NASA Technical Reports Server (NTRS)

Collins, O.

1993-01-01

In Reed-Solomon codes and all other maximum distance separable codes, there is an intrinsic relationship between the size of the symbols in a codeword and the length of the codeword. Increasing the number of symbols in a codeword to improve the efficiency of the coding system thus requires using a larger set of symbols. However, long Reed-Solomon codes are difficult to implement and many communications or storage systems cannot easily accommodate an increased symbol size, e.g., M-ary frequency shift keying (FSK) and photon-counting pulse-position modulation demand a fixed symbol size. A technique for sharing redundancy among many different Reed-Solomon codewords to achieve the efficiency attainable in long Reed-Solomon codes without increasing the symbol size is described. Techniques both for calculating the performance of these new codes and for determining their encoder and decoder complexities is presented. These complexities are usually found to be substantially lower than conventional Reed-Solomon codes of similar performance.

Life jacket design affects dorsal head and chest exposure, core cooling, and cognition in 10 degrees C water.

PubMed

Lockhart, Tamara L; Jamieson, Christopher P; Steinman, Alan M; Giesbrecht, Gordon G

2005-10-01

Personal floatation devices (PFDs) differ in whether they maintain the head out of the water or allow the dorsum of the head to be immersed. Partial head submersion may hasten systemic cooling, incapacitation, and death in cold water. Six healthy male volunteers (mean age = 26.8 yr; height = 184 cm; weight = 81 kg; body fat = 20%) were immersed in 10 degrees C water for 65 min, or until core temperature = 34 degrees C, under three conditions: PFD#1 maintained the head and upper chest out of the water; PFD#2 allowed the dorsal head and whole body to be immersed; and an insulated drysuit (control) allowed the dorsal head to be immersed. Mental performance tests included: logic reasoning test; Stroop word-color test; digit symbol coding; backward digit span; and paced auditory serial addition test (PASAT). Core cooling was significantly faster for PFD#2 (2.8 +/- 1.6 degrees C x h(-1)) than for PFD#1 (1.5 +/- 0.7 degrees C x h(-1)) or for the drysuit (0.4 +/- 0.2 degrees C x h(-1)). Although no statistically significant effects on cognitive performance were noted for the individual PFDs and drysuit, when analyzed as a group, four of the tests of cognitive performance (Stroop word-color, digit symbol coding, backward digit span, and PASAT) showed significant correlations between decreasing core temperature to 34 degrees C and diminished cognitive performance. Performance in more complicated mental tasks was adversely affected as core temperature decreased to 34 degrees C. The PFD that kept the head and upper chest out of the water preserved body heat and mental performance better than the PFD that produced horizontal flotation.

Orthographic Coding: Brain Activation for Letters, Symbols, and Digits.

PubMed

Carreiras, Manuel; Quiñones, Ileana; Hernández-Cabrera, Juan Andrés; Duñabeitia, Jon Andoni

2015-12-01

The present experiment investigates the input coding mechanisms of 3 common printed characters: letters, numbers, and symbols. Despite research in this area, it is yet unclear whether the identity of these 3 elements is processed through the same or different brain pathways. In addition, some computational models propose that the position-in-string coding of these elements responds to general flexible mechanisms of the visual system that are not character-specific, whereas others suggest that the position coding of letters responds to specific processes that are different from those that guide the position-in-string assignment of other types of visual objects. Here, in an fMRI study, we manipulated character position and character identity through the transposition or substitution of 2 internal elements within strings of 4 elements. Participants were presented with 2 consecutive visual strings and asked to decide whether they were the same or different. The results showed: 1) that some brain areas responded more to letters than to numbers and vice versa, suggesting that processing may follow different brain pathways; 2) that the left parietal cortex is involved in letter identity, and critically in letter position coding, specifically contributing to the early stages of the reading process; and that 3) a stimulus-specific mechanism for letter position coding is operating during orthographic processing. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Serial position effects in the identification of letters, digits, and symbols.

PubMed

Tydgat, Ilse; Grainger, Jonathan

2009-04-01

In 6 experiments, the authors investigated the form of serial position functions for identification of letters, digits, and symbols presented in strings. The results replicated findings obtained with the target search paradigm, showing an interaction between the effects of serial position and type of stimulus, with symbols generating a distinct serial position function compared with letters and digits. When the task was 2-alternative forced choice, this interaction was driven almost exclusively by performance at the first position in the string, with letters and digits showing much higher levels of accuracy than symbols at this position. A final-position advantage was reinstated in Experiment 6 by placing the two alternative responses below the target string. The end-position (first and last positions) advantage for letters and digits compared with symbol stimuli was further confirmed with the bar-probe technique (postcued partial report) in Experiments 5 and 6. Overall, the results further support the existence of a specialized mechanism designed to optimize processing of strings of letters and digits by modifying the size and shape of retinotopic character detectors' receptive fields. (c) 2009 APA, all rights reserved.

Epidemiological Study of Mild Tramautic Brain Injury Sequelae Cause by Blast Exposure During Operations Iraqi Freedom and Enduring Freedom

DTIC Science & Technology

2012-10-01

Principal Investigator September, 2008 20 (see: VCU sub- award) David X. Cifu, MD Co-Investigator September, 2008 5 (VCU sub-award) Jessica...proven reliability: Wechsler Test of Adult Reading (WTAR, pre- morbid IQ estimate),(Mathias, Bowden, Bigler, & Rosenfeld, 2007) Conners Continuous...II (CVLT-II) (learning and working memory),(Vanderploeg et al., 2005) Wechsler Adult Intelligence Scale III (WAIS-III) items: Digit Symbol Coding

3D Encoding of Musical Score Information and the Playback Method Used by the Cellular Phone

NASA Astrophysics Data System (ADS)

Kubo, Hitoshi; Sugiura, Akihiko

Recently, 3G cellular phone that can take a movie has spread by improving the digital camera function. And, 2Dcode has accurate readout and high operability. And it has spread as an information transmission means. However, the symbol is expanded and complicated when information of 2D codes increases. To solve these, 3D code was proposed. But it need the special equipment for readout, and specializes in the enhancing reality feeling technology. Therefore, it is difficult to apply it to the cellular phone. And so, we propose 3D code that can be recognized by the movie shooting function of the cellular phone. And, score information was encoded. We apply Gray Code to the property of music, and encode it. And the effectiveness was verified.

Effects of low sampling rate in the digital data-transition tracking loop

NASA Technical Reports Server (NTRS)

Mileant, A.; Million, S.; Hinedi, S.

1994-01-01

This article describes the performance of the all-digital data-transition tracking loop (DTTL) with coherent and noncoherent sampling using nonlinear theory. The effects of few samples per symbol and of noncommensurate sampling and symbol rates are addressed and analyzed. Their impact on the probability density and variance of the phase error are quantified through computer simulations. It is shown that the performance of the all-digital DTTL approaches its analog counterpart when the sampling and symbol rates are noncommensurate (i.e., the number of samples per symbol is an irrational number). The loop signal-to-noise ratio (SNR) (inverse of phase error variance) degrades when the number of samples per symbol is an odd integer but degrades even further for even integers.

Fractal-Based Image Compression

DTIC Science & Technology

1989-09-01

6. A Mercedes Benz symbol generated using an IFS code ................. 21 7. (a) U-A fern and (b) A-0 fern generated with RIFS codes...22 8. Construction of the Mercedes - Benz symbol using RIFS ................ 23 9. The regenerated perfect image of the Mercedes - Benz symbol using R IF...quite often, it cannot be done with a reasonable number of transforms. As an example, the Mercedes Benz symbol generated using an IFS code is illustrated

The Multidimensional Influence of Acculturation on Digit Symbol-Coding and Wisconsin Card Sorting Test in Hispanics.

PubMed

Krch, Denise; Lequerica, Anthony; Arango-Lasprilla, Juan Carlos; Rogers, Heather L; DeLuca, John; Chiaravalloti, Nancy D

2015-01-01

The purpose of the current study was to evaluate the relative contribution of acculturation to two tests of nonverbal test performance in Hispanics. This study compared 40 Hispanic and 20 non-Hispanic whites on Digit Symbol-Coding (DSC) and the Wisconsin Card Sorting Test (WCST) and evaluated the relative contribution of the various acculturation components to cognitive test performance in the Hispanic group. Hispanics performed significantly worse on DSC and WCST relative to non-Hispanic whites. Multiple regressions conducted within the Hispanic group revealed that language use uniquely accounted for 11.0% of the variance on the DSC, 18.8% of the variance on WCST categories completed, and 13.0% of the variance in perseverative errors on the WCST. Additionally, years of education in the United States uniquely accounted for 14.9% of the variance in DSC. The significant impact of acculturation on DSC and WCST lends support that nonverbal cognitive tests are not necessarily culture free. The differential contribution of acculturation proxies highlights the importance of considering these separate components when interpreting performance on neuropsychological tests in clinical and research settings. Factors, such as the country where education was received, may in fact be more meaningful information than the years of education of education attained. Thus, acculturation should be considered an important factor in any cognitive evaluation of culturally diverse individuals.

R34D1NG W0RD5 W1TH NUMB3R5.

PubMed

Perea, Manuel; Duñabeitia, Jon Andoni; Carreiras, Manuel

2008-02-01

Letter identities and number identities are usually thought to imply different cortical mechanisms. Specifically, the left fusiform gyrus responds more to letters than to digits (T. A. Polk et al., 2002). However, a widely circulated statement on the internet illustrates that it is possible to use numbers (leet digits) as parts of words, 4ND TH3 R35ULT1NG S3NT3NC3 C4N B3 R34D W1TH0UT GR34T 3FF0RT. Two masked priming lexical decision experiments were conducted to determine whether leet digits produce (automatic) lexical activation. Results showed that words are identified substantially faster when they are preceded by a masked leet word (M4T3R14L-MATERIAL) than when they are preceded by a control condition with other letters or digits. In addition, there was only a negligible advantage of the identity condition over the related leet condition. This leet-priming effect is not specific to numbers: A prime in which leet digits are replaced by letter-like symbols (M(Delta symbol)T(euro symbol)R!(Delta symbol)L - MATERIAL) facilitates word processing to the same degree as an identity prime. Therefore, the cognitive system regularizes the shape of the leet digits and letter-like symbols embedded in words with very little cost.

Serial Position Effects in the Identification of Letters, Digits, and Symbols

ERIC Educational Resources Information Center

Tydgat, Ilse; Grainger, Jonathan

2009-01-01

In 6 experiments, the authors investigated the form of serial position functions for identification of letters, digits, and symbols presented in strings. The results replicated findings obtained with the target search paradigm, showing an interaction between the effects of serial position and type of stimulus, with symbols generating a distinct…

Compression embedding

DOEpatents

Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

1998-03-10

A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique is disclosed. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method. 11 figs.

Compression embedding

DOEpatents

Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

1998-01-01

A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method.

Unconscious Addition: When We Unconsciously Initiate and Follow Arithmetic Rules

ERIC Educational Resources Information Center

Ric, Francois; Muller, Dominique

2012-01-01

This research shows that people can unconsciously initiate and follow arithmetic rules (e.g., addition). Participants were asked to detect whether a symbol was a digit. This symbol was preceded by 2 digits and a subliminal instruction: "add" or a control instruction. Participants were faster at identifying a symbol as a number when the…

Rapid Processing of Letters, Digits and Symbols: What Purely Visual-Attentional Deficit in Developmental Dyslexia?

ERIC Educational Resources Information Center

Ziegler, Johannes C.; Pech-Georgel, Catherine; Dufau, Stephane; Grainger, Jonathan

2010-01-01

Visual-attentional theories of dyslexia predict deficits for dyslexic children not only for the perception of letter strings but also for non-alphanumeric symbol strings. This prediction was tested in a two-alternative forced-choice paradigm with letters, digits, and symbols. Children with dyslexia showed significant deficits for letter and digit…

The physics of symbols: bridging the epistemic cut.

PubMed

Pattee, H H

2001-01-01

Evolution requires the genotype-phenotype distinction, a primeval epistemic cut that separates energy-degenerate, rate-independent genetic symbols from the rate-dependent dynamics of construction that they control. This symbol-matter or subject-object distinction occurs at all higher levels where symbols are related to a referent by an arbitrary code. The converse of control is measurement in which a rate-dependent dynamical state is coded into quiescent symbols. Non-integrable constraints are one necessary condition for bridging the epistemic cut by measurement, control, and coding. Additional properties of heteropolymer constraints are necessary for biological evolution.

Symbolic and non symbolic numerical representation in adults with and without developmental dyscalculia

PubMed Central

2012-01-01

Background The question whether Developmental Dyscalculia (DD; a deficit in the ability to process numerical information) is the result of deficiencies in the non symbolic numerical representation system (e.g., a group of dots) or in the symbolic numerical representation system (e.g., Arabic numerals) has been debated in scientific literature. It is accepted that the non symbolic system is divided into two different ranges, the subitizing range (i.e., quantities from 1-4) which is processed automatically and quickly, and the counting range (i.e., quantities larger than 4) which is an attention demanding procedure and is therefore processed serially and slowly. However, so far no study has tested the automaticity of symbolic and non symbolic representation in DD participants separately for the subitizing and the counting ranges. Methods DD and control participants undergo a novel version of the Stroop task, i.e., the Enumeration Stroop. They were presented with a random series of between one and nine written digits, and were asked to name either the relevant written digit (in the symbolic task) or the relevant quantity of digits (in the non symbolic task) while ignoring the irrelevant aspect. Result DD participants, unlike the control group, didn't show any congruency effect in the subitizing range of the non symbolic task. Conclusion These findings suggest that DD may be impaired in the ability to process symbolic numerical information or in the ability to automatically associate the two systems (i.e., the symbolic vs. the non symbolic). Additionally DD have deficiencies in the non symbolic counting range. PMID:23190433

Symbolic and non symbolic numerical representation in adults with and without developmental dyscalculia.

PubMed

Furman, Tamar; Rubinsten, Orly

2012-11-28

The question whether Developmental Dyscalculia (DD; a deficit in the ability to process numerical information) is the result of deficiencies in the non symbolic numerical representation system (e.g., a group of dots) or in the symbolic numerical representation system (e.g., Arabic numerals) has been debated in scientific literature. It is accepted that the non symbolic system is divided into two different ranges, the subitizing range (i.e., quantities from 1-4) which is processed automatically and quickly, and the counting range (i.e., quantities larger than 4) which is an attention demanding procedure and is therefore processed serially and slowly. However, so far no study has tested the automaticity of symbolic and non symbolic representation in DD participants separately for the subitizing and the counting ranges. DD and control participants undergo a novel version of the Stroop task, i.e., the Enumeration Stroop. They were presented with a random series of between one and nine written digits, and were asked to name either the relevant written digit (in the symbolic task) or the relevant quantity of digits (in the non symbolic task) while ignoring the irrelevant aspect. DD participants, unlike the control group, didn't show any congruency effect in the subitizing range of the non symbolic task. These findings suggest that DD may be impaired in the ability to process symbolic numerical information or in the ability to automatically associate the two systems (i.e., the symbolic vs. the non symbolic). Additionally DD have deficiencies in the non symbolic counting range.

Representation of DNA sequences in genetic codon context with applications in exon and intron prediction.

PubMed

Yin, Changchuan

2015-04-01

To apply digital signal processing (DSP) methods to analyze DNA sequences, the sequences first must be specially mapped into numerical sequences. Thus, effective numerical mappings of DNA sequences play key roles in the effectiveness of DSP-based methods such as exon prediction. Despite numerous mappings of symbolic DNA sequences to numerical series, the existing mapping methods do not include the genetic coding features of DNA sequences. We present a novel numerical representation of DNA sequences using genetic codon context (GCC) in which the numerical values are optimized by simulation annealing to maximize the 3-periodicity signal to noise ratio (SNR). The optimized GCC representation is then applied in exon and intron prediction by Short-Time Fourier Transform (STFT) approach. The results show the GCC method enhances the SNR values of exon sequences and thus increases the accuracy of predicting protein coding regions in genomes compared with the commonly used 4D binary representation. In addition, this study offers a novel way to reveal specific features of DNA sequences by optimizing numerical mappings of symbolic DNA sequences.

A measure of short-term visual memory based on the WISC-R coding subtest.

PubMed

Collaer, M L; Evans, J R

1982-07-01

Adapted the Coding subtest of the WISC-R to provide a measure of visual memory. Three hundred and five children, aged 8 through 12, were administered the Coding test using standard directions. A few seconds after completion the key was taken away, and each was given a paper with only the digits and asked to write the appropriate matching symbol below each. This was termed "Coding Recall." To provide validity data, a subgroup of 50 Ss also was administered the Attention Span for Letters subtest from the Detroit Tests of Learning Aptitude (as a test of visual memory for sequences of letters) and a Bender Gestalt recall test (as a measure of visual memory for geometric forms). Coding Recall means and standard deviations are reported separately by sex and age level. Implications for clinicans are discussed. Reservations about clinical use of the data are given in view of the possible lack of representativeness of the sample used and the limited reliability and validity of Coding Recall.

FGDC Digital Cartographic Standard for Geologic Map Symbolization (PostScript Implementation)

USGS Publications Warehouse

,

2006-01-01

PLEASE NOTE: This now-approved 'FGDC Digital Cartographic Standard for Geologic Map Symbolization (PostScript Implementation)' officially supercedes its earlier (2000) Public Review Draft version (see 'Earlier Versions of the Standard' below). In August 2006, the Digital Cartographic Standard for Geologic Map Symbolization was officially endorsed by the Federal Geographic Data Committee (FGDC) as the national standard for the digital cartographic representation of geologic map features (FGDC Document Number FGDC-STD-013-2006). Presented herein is the PostScript Implementation of the standard, which will enable users to directly apply the symbols in the standard to geologic maps and illustrations prepared in desktop illustration and (or) publishing software. The FGDC Digital Cartographic Standard for Geologic Map Symbolization contains descriptions, examples, cartographic specifications, and notes on usage for a wide variety of symbols that may be used on typical, general-purpose geologic maps and related products such as cross sections. The standard also can be used for different kinds of special-purpose or derivative map products and databases that may be focused on a specific geoscience topic (for example, slope stability) or class of features (for example, a fault map). The standard is scale-independent, meaning that the symbols are appropriate for use with geologic mapping compiled or published at any scale. It will be useful to anyone who either produces or uses geologic map information, whether in analog or digital form. Please be aware that this standard is not intended to be used inflexibly or in a manner that will limit one's ability to communicate the observations and interpretations gained from geologic mapping. In certain situations, a symbol or its usage might need to be modified in order to better represent a particular feature on a geologic map or cross section. This standard allows the use of any symbol that doesn't conflict with others in the standard, provided that it is clearly explained on the map and in the database. In addition, modifying the size, color, and (or) lineweight of an existing symbol to suit the needs of a particular map or output device also is permitted, provided that the modified symbol's appearance is not too similar to another symbol on the map. Be aware, however, that reducing lineweights below .125 mm (.005 inch) may cause symbols to plot incorrectly if output at higher resolutions (1800 dpi or higher). For guidelines on symbol usage, as well as on color design and map labeling, please refer to the standard's introductory text. Also found there are informational sections covering concepts of geologic mapping and some definitions of geologic map features, as well as sections on the newly defined concepts and terminology for the scientific confidence and locational accuracy of geologic map features. More information on both the past development and the future maintenance of the FGDC Digital Cartographic Standard for Geologic Map Symbolization can be found at the FGDC Geologic Data Subcommittee website (http://ngmdb.usgs.gov/fgdc_gds/). Earlier Versions of the Standard

On codes with multi-level error-correction capabilities

NASA Technical Reports Server (NTRS)

Lin, Shu

1987-01-01

In conventional coding for error control, all the information symbols of a message are regarded equally significant, and hence codes are devised to provide equal protection for each information symbol against channel errors. However, in some occasions, some information symbols in a message are more significant than the other symbols. As a result, it is desired to devise codes with multilevel error-correcting capabilities. Another situation where codes with multi-level error-correcting capabilities are desired is in broadcast communication systems. An m-user broadcast channel has one input and m outputs. The single input and each output form a component channel. The component channels may have different noise levels, and hence the messages transmitted over the component channels require different levels of protection against errors. Block codes with multi-level error-correcting capabilities are also known as unequal error protection (UEP) codes. Structural properties of these codes are derived. Based on these structural properties, two classes of UEP codes are constructed.

Rapid parallel semantic processing of numbers without awareness.

PubMed

Van Opstal, Filip; de Lange, Floris P; Dehaene, Stanislas

2011-07-01

In this study, we investigate whether multiple digits can be processed at a semantic level without awareness, either serially or in parallel. In two experiments, we presented participants with two successive sets of four simultaneous Arabic digits. The first set was masked and served as a subliminal prime for the second, visible target set. According to the instructions, participants had to extract from the target set either the mean or the sum of the digits, and to compare it with a reference value. Results showed that participants applied the requested instruction to the entire set of digits that was presented below the threshold of conscious perception, because their magnitudes jointly affected the participant's decision. Indeed, response decision could be accurately modeled as a sigmoid logistic function that pooled together the evidence provided by the four targets and, with lower weights, the four primes. In less than 800ms, participants successfully approximated the addition and mean tasks, although they tended to overweight the large numbers, particularly in the sum task. These findings extend previous observations on ensemble coding by showing that set statistics can be extracted from abstract symbolic stimuli rather than low-level perceptual stimuli, and that an ensemble code can be represented without awareness. Copyright © 2011 Elsevier B.V. All rights reserved.

Are numbers, size and brightness equally efficient in orienting visual attention? Evidence from an eye-tracking study.

PubMed

Bulf, Hermann; Macchi Cassia, Viola; de Hevia, Maria Dolores

2014-01-01

A number of studies have shown strong relations between numbers and oriented spatial codes. For example, perceiving numbers causes spatial shifts of attention depending upon numbers' magnitude, in a way suggestive of a spatially oriented, mental representation of numbers. Here, we investigated whether this phenomenon extends to non-symbolic numbers, as well as to the processing of the continuous dimensions of size and brightness, exploring whether different quantitative dimensions are equally mapped onto space. After a numerical (symbolic Arabic digits or non-symbolic arrays of dots; Experiment 1) or a non-numerical cue (shapes of different size or brightness level; Experiment 2) was presented, participants' saccadic response to a target that could appear either on the left or the right side of the screen was registered using an automated eye-tracker system. Experiment 1 showed that, both in the case of Arabic digits and dot arrays, right targets were detected faster when preceded by large numbers, and left targets were detected faster when preceded by small numbers. Participants in Experiment 2 were faster at detecting right targets when cued by large-sized shapes and left targets when cued by small-sized shapes, whereas brightness cues did not modulate the detection of peripheral targets. These findings indicate that looking at a symbolic or a non-symbolic number induces attentional shifts to a peripheral region of space that is congruent with the numbers' relative position on a mental number line, and that a similar shift in visual attention is induced by looking at shapes of different size. More specifically, results suggest that, while the dimensions of number and size spontaneously map onto an oriented space, the dimension of brightness seems to be independent at a certain level of magnitude elaboration from the dimensions of spatial extent and number, indicating that not all continuous dimensions are equally mapped onto space.

Bi-orthogonal Symbol Mapping and Detection in Optical CDMA Communication System

NASA Astrophysics Data System (ADS)

Liu, Maw-Yang

2017-12-01

In this paper, the bi-orthogonal symbol mapping and detection scheme is investigated in time-spreading wavelength-hopping optical CDMA communication system. The carrier-hopping prime code is exploited as signature sequence, whose put-of-phase autocorrelation is zero. Based on the orthogonality of carrier-hopping prime code, the equal weight orthogonal signaling scheme can be constructed, and the proposed scheme using bi-orthogonal symbol mapping and detection can be developed. The transmitted binary data bits are mapped into corresponding bi-orthogonal symbols, where the orthogonal matrix code and its complement are utilized. In the receiver, the received bi-orthogonal data symbol is fed into the maximum likelihood decoder for detection. Under such symbol mapping and detection, the proposed scheme can greatly enlarge the Euclidean distance; hence, the system performance can be drastically improved.

A Degree Distribution Optimization Algorithm for Image Transmission

NASA Astrophysics Data System (ADS)

Jiang, Wei; Yang, Junjie

2016-09-01

Luby Transform (LT) code is the first practical implementation of digital fountain code. The coding behavior of LT code is mainly decided by the degree distribution which determines the relationship between source data and codewords. Two degree distributions are suggested by Luby. They work well in typical situations but not optimally in case of finite encoding symbols. In this work, the degree distribution optimization algorithm is proposed to explore the potential of LT code. Firstly selection scheme of sparse degrees for LT codes is introduced. Then probability distribution is optimized according to the selected degrees. In image transmission, bit stream is sensitive to the channel noise and even a single bit error may cause the loss of synchronization between the encoder and the decoder. Therefore the proposed algorithm is designed for image transmission situation. Moreover, optimal class partition is studied for image transmission with unequal error protection. The experimental results are quite promising. Compared with LT code with robust soliton distribution, the proposed algorithm improves the final quality of recovered images obviously with the same overhead.

Exploring Modality Compatibility in the Response-Effect Compatibility Paradigm.

PubMed

Földes, Noémi; Philipp, Andrea M; Badets, Arnaud; Koch, Iring

2017-01-01

According to ideomotor theory , action planning is based on anticipatory perceptual representations of action-effects. This aspect of action control has been investigated in studies using the response-effect compatibility (REC) paradigm, in which responses have been shown to be facilitated if ensuing perceptual effects share codes with the response based on dimensional overlap (i.e., REC). Additionally, according to the notion of ideomotor compatibility, certain response-effect (R-E) mappings will be stronger than others because some response features resemble the anticipated sensory response effects more strongly than others (e.g., since vocal responses usually produce auditory effects, an auditory stimulus should be anticipated in a stronger manner following vocal responses rather than following manual responses). Yet, systematic research on this matter is lacking. In the present study, two REC experiments aimed to explore the influence of R-E modality mappings. In Experiment 1, vocal number word responses produced visual effects on the screen (digits vs. number words; i.e., visual-symbolic vs. visual-verbal effect codes). The REC effect was only marginally larger for visual-verbal than for visual-symbolic effects. Using verbal effect codes in Experiment 2, we found that the REC effect was larger with auditory-verbal R-E mapping than with visual-verbal R-E mapping. Overall, the findings support the hypothesis of a role of R-E modality mappings in REC effects, suggesting both further evidence for ideomotor accounts as well as code-specific and modality-specific contributions to effect anticipation.

Intrauterine Exposure to Methylmercury and Neurocognitive Functions: Minamata Disease.

PubMed

Yorifuji, Takashi; Kato, Tsuguhiko; Kado, Yoko; Tokinobu, Akiko; Yamakawa, Michiyo; Tsuda, Toshihide; Sanada, Satoshi

2015-01-01

A large-scale food poisoning caused by methylmercury was identified in Minamata, Japan, in the 1950s. The severe intrauterine exposure cases are well known, although the possible impact of low-to-moderate methylmercury exposure in utero are rarely investigated. We examined neurocognitive functions among 22 participants in Minamata, mainly using an intelligence quotient test (Wechsler Adults Intelligent Scale III), in 2012/2013. The participants tended to score low on the Index score of processing speed (PS) relative to full-scale IQ, and discrepancies between PS and other scores within each participant were observed. The lower score on PS was due to deficits in digit symbol-coding and symbol search and was associated with methylmercury concentration in umbilical cords. The residents who experienced low-to-moderate methylmercury exposure including prenatal one in Minamata manifested deficits in their cognitive functions, processing speed in particular.

Analysis of an all-digital maximum likelihood carrier phase and clock timing synchronizer for eight phase-shift keying modulation

NASA Astrophysics Data System (ADS)

Degaudenzi, Riccardo; Vanghi, Vieri

1994-02-01

In all-digital Trellis-Coded 8PSK (TC-8PSK) demodulator well suited for VLSI implementation, including maximum likelihood estimation decision-directed (MLE-DD) carrier phase and clock timing recovery, is introduced and analyzed. By simply removing the trellis decoder the demodulator can efficiently cope with uncoded 8PSK signals. The proposed MLE-DD synchronization algorithm requires one sample for the phase and two samples per symbol for the timing loop. The joint phase and timing discriminator characteristics are analytically derived and numerical results checked by means of computer simulations. An approximated expression for steady-state carrier phase and clock timing mean square error has been derived and successfully checked with simulation findings. Synchronizer deviation from the Cramer Rao bound is also discussed. Mean acquisition time for the digital synchronizer has also been computed and checked, using the Monte Carlo simulation technique. Finally, TC-8PSK digital demodulator performance in terms of bit error rate and mean time to lose lock, including digital interpolators and synchronization loops, is presented.

Unpacking symbolic number comparison and its relation with arithmetic in adults.

PubMed

Sasanguie, Delphine; Lyons, Ian M; De Smedt, Bert; Reynvoet, Bert

2017-08-01

Symbolic number - or digit - comparison has been a central tool in the domain of numerical cognition for decades. More recently, individual differences in performance on this task have been shown to robustly relate to individual differences in more complex math processing - a result that has been replicated across many different age groups. In this study, we 'unpack' the underlying components of digit comparison (i.e. digit identification, digit to number-word matching, digit ordering and general comparison) in a sample of adults. In a first experiment, we showed that digit comparison performance was most strongly related to digit ordering ability - i.e., the ability to judge whether symbolic numbers are in numerical order. Furthermore, path analyses indicated that the relation between digit comparison and arithmetic was partly mediated by digit ordering and fully mediated when non-numerical (letter) ordering was also entered into the model. In a second experiment, we examined whether a general order working memory component could account for the relation between digit comparison and arithmetic. It could not. Instead, results were more consistent with the notion that fluent access and activation of long-term stored associations between numbers explains the relation between arithmetic and both digit comparison and digit ordering tasks. Copyright © 2017 Elsevier B.V. All rights reserved.

Symbol Sense Behavior in Digital Activities

ERIC Educational Resources Information Center

Bokhove, Christian; Drijvers, Paul

2010-01-01

The algebraic expertise that mathematics education is aiming for includes both procedural skills and conceptual understanding. To capture the latter, notions such as symbol sense, gestalt view and visual salience have been developed. We wonder if digital activities can be designed that not only require procedural algebraic skills, but also invite…

The Reed-Solomon encoders: Conventional versus Berlekamp's architecture

NASA Technical Reports Server (NTRS)

Perlman, M.; Lee, J. J.

1982-01-01

Concatenated coding was adopted for interplanetary space missions. Concatenated coding was employed with a convolutional inner code and a Reed-Solomon (RS) outer code for spacecraft telemetry. Conventional RS encoders are compared with those that incorporate two architectural features which approximately halve the number of multiplications of a set of fixed arguments by any RS codeword symbol. The fixed arguments and the RS symbols are taken from a nonbinary finite field. Each set of multiplications is bit-serially performed and completed during one (bit-serial) symbol shift. All firmware employed by conventional RS encoders is eliminated.

Preparation and Use of Liposomes in Immunological Studies

DTIC Science & Technology

1993-01-01

SYMBOL MFI RO W 0 E FANIZATION Division of Bioctmnistry El O9V09W399 6c. ADDRESS (City, State, and ZIP Code). DRESS(Ci State, and ZIP Code) "Walter Reed...Anuv Institute of Research 1 A Washington. DC 20307-5100 oC" 8a. NAME OF FUNDING/SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION...12a NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) 22c. OFFICE SYMBOL OD Form 1473, JUN 86 Previous editions are obsolete

Carotid atherosclerosis predicts lower cognitive test results: a 7-year follow-up study of 4,371 stroke-free subjects - the Tromsø study.

PubMed

Arntzen, Kjell Arne; Schirmer, Henrik; Johnsen, Stein Harald; Wilsgaard, Tom; Mathiesen, Ellisiv B

2012-01-01

Carotid artery atherosclerosis is a major risk factor for stroke and subsequent cognitive impairment. Prospective population studies have shown associations between carotid intima-media thickness (IMT) and stenosis and cognitive decline and dementia in elderly stroke-free persons, whereas results in the middle-aged are conflicting. In this prospective population-based study, 4,371 stroke-free middle-aged participants underwent carotid ultrasound examination and assessment of vascular risk factors at baseline and were tested for cognitive function 7 years later. Associations between IMT, number of plaques and total plaque area and cognitive test scores on verbal memory test, digit symbol-coding test and tapping test were assessed in linear regression models. In the multivariable analyses adjusted for sex, age, education, depression and vascular risk factors, the presence of plaques was significantly associated with lower test scores on the verbal memory test (p = 0.01) and on the digit symbol-coding test (p = 0.03). The number of plaques (p = 0.01) and the total plaque area (p = 0.02) were associated with lower scores on the verbal memory test. No significant association was seen between common carotid artery IMT and cognitive test scores. The tapping test was not associated with the carotid ultrasound variables. In this middle-aged general population, subclinical carotid atherosclerosis measured as the presence of plaques, number of plaques and total plaque area were independent long-term predictors of lower cognitive test scores. Copyright © 2012 S. Karger AG, Basel.

The puzzle of processing speed, memory, and executive function impairments in schizophrenia: fitting the pieces together.

PubMed

Knowles, Emma E M; Weiser, Mark; David, Anthony S; Glahn, David C; Davidson, Michael; Reichenberg, Abraham

2015-12-01

Substantial impairment in performance on the digit-symbol substitution task in patients with schizophrenia is well established, which has been widely interpreted as denoting a specific impairment in processing speed. However, other higher order cognitive functions might be more critical to performance on this task. To date, this idea has not been rigorously investigated in patients with schizophrenia. Neuropsychological measures of processing speed, memory, and executive functioning were completed by 125 patients with schizophrenia and 272 control subjects. We implemented a series of confirmatory factor and structural regression modeling to build an integrated model of processing speed, memory, and executive function with which to deconstruct the digit-symbol substitution task and characterize discrepancies between patients with schizophrenia and control subjects. The overall structure of the processing speed, memory, and executive function model was the same across groups (χ(2) = 208.86, p > .05), but the contribution of the specific cognitive domains to coding task performance differed significantly. When completing the task, control subjects relied on executive function and, indirectly, on working memory ability, whereas patients with schizophrenia used an alternative set of cognitive operations whereby they relied on the same processes required to complete verbal fluency tasks. Successful coding task performance relies predominantly on executive function, rather than processing speed or memory. Patients with schizophrenia perform poorly on this task because of an apparent lack of appropriate executive function input; they rely instead on an alternative cognitive pathway. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Application of grammar-based codes for lossless compression of digital mammograms

NASA Astrophysics Data System (ADS)

Li, Xiaoli; Krishnan, Srithar; Ma, Ngok-Wah

2006-01-01

A newly developed grammar-based lossless source coding theory and its implementation was proposed in 1999 and 2000, respectively, by Yang and Kieffer. The code first transforms the original data sequence into an irreducible context-free grammar, which is then compressed using arithmetic coding. In the study of grammar-based coding for mammography applications, we encountered two issues: processing time and limited number of single-character grammar G variables. For the first issue, we discover a feature that can simplify the matching subsequence search in the irreducible grammar transform process. Using this discovery, an extended grammar code technique is proposed and the processing time of the grammar code can be significantly reduced. For the second issue, we propose to use double-character symbols to increase the number of grammar variables. Under the condition that all the G variables have the same probability of being used, our analysis shows that the double- and single-character approaches have the same compression rates. By using the methods proposed, we show that the grammar code can outperform three other schemes: Lempel-Ziv-Welch (LZW), arithmetic, and Huffman on compression ratio, and has similar error tolerance capabilities as LZW coding under similar circumstances.

Toward digital geologic map standards: a progress report

USGS Publications Warehouse

Ulrech, George E.; Reynolds, Mitchell W.; Taylor, Richard B.

1992-01-01

Establishing modern scientific and technical standards for geologic maps and their derivative map products is vital to both producers and users of such maps as we move into an age of digital cartography. Application of earth-science data in complex geographic information systems, acceleration of geologic map production, and reduction of population costs require that national standards be developed for digital geologic cartography and computer analysis. Since December 1988, under commission of the Chief Geologic of the U.S. Geological Survey and the mandate of the National Geologic Mapping Program (with added representation from the Association of American State Geologists), a committee has been designing a comprehensive set of scientific map standards. Three primary issues were: (1) selecting scientific symbology and its digital representation; (2) creating an appropriate digital coding system that characterizes geologic features with respect to their physical properties, stratigraphic and structural relations, spatial orientation, and interpreted mode of origin; and (3) developing mechanisms for reporting levels of certainty for descriptive as well as measured properties. Approximately 650 symbols for geoscience maps, including present usage of the U.S Geological Survey, state geological surveys, industry, and academia have been identified and tentatively adopted. A proposed coding system comprises four-character groupings of major and minor codes that can identify all attributes of a geologic feature. Such a coding system allows unique identification of as many as 105 geologic names and values on a given map. The new standard will track closely the latest developments of the Proposed Standard for Digital Cartographic Data soon to be submitted to the National Institute of Standards and Technology by the Federal Interagency Coordinating Committee on Digital Cartography. This standard will adhere generally to the accepted definitions and specifications for spatial data transfer. It will require separate specifications of digital cartographic quality relating to positional accuracy and ranges of measured and interpreted values such as geologic age and rock composition. Provisional digital geologic map standards will be published for trial implementation. After approximately two years, when comments on the proposed standards have been solicited and modifications made, formal adoption of the standards will be recommended. Widespread acceptance of the new standards will depend on their applicability to the broadest range of earth-science map products and their adaptability to changing cartographic technology.

Modified signed-digit trinary arithmetic by using optical symbolic substitution.

PubMed

Awwal, A A; Islam, M N; Karim, M A

1992-04-10

Carry-free addition and borrow-free subtraction of modified signed-digit trinary numbers with optical symbolic substitution are presented. The proposed two-step and three-step algorithms can be easily implemented by using phase-only holograms, optical content-addressable memories, a multichannel correlator, or a polarization-encoded optical shadow-casting system.

Modified signed-digit trinary arithmetic by using optical symbolic substitution

NASA Astrophysics Data System (ADS)

Awwal, A. A. S.; Islam, M. N.; Karim, M. A.

1992-04-01

Carry-free addition and borrow-free subtraction of modified signed-digit trinary numbers with optical symbolic substitution are presented. The proposed two-step and three-step algorithms can be easily implemented by using phase-only holograms, optical content-addressable memories, a multichannel correlator, or a polarization-encoded optical shadow-casting system.

Test-retest reliability and practice effects of a rapid screen of mild traumatic brain injury.

PubMed

De Monte, Veronica Eileen; Geffen, Gina Malke; Kwapil, Karleigh

2005-07-01

Test-retest reliabilities and practice effects of measures from the Rapid Screen of Concussion (RSC), in addition to the Digit Symbol Substitution Test (Digit Symbol), were examined. Twenty five male participants were tested three times; each testing session scheduled a week apart. The test-retest reliability estimates for most measures were reasonably good, ranging from .79 to .97. An exception was the delayed word recall test, which has had a reliability estimate of .66 for the first retest, and .59 for the second retest. Practice effects were evident from Times 1 to 2 on the sentence comprehension and delayed recall subtests of the RSC, Digit Symbol and a composite score. There was also a practice effect of the same magnitude found from Time 2 to Time 3 on Digit Symbol, delayed recall and the composite score. Statistics on measures for both the first and second retest intervals, with associated practice effects, are presented to enable the calculation of reliable change indices (RCI). The RCI may be used to assess any improvement in cognitive functioning after mild Traumatic Brain Injury.

A Network Meta-Analysis Comparing Effects of Various Antidepressant Classes on the Digit Symbol Substitution Test (DSST) as a Measure of Cognitive Dysfunction in Patients with Major Depressive Disorder.

PubMed

Baune, Bernhard T; Brignone, Mélanie; Larsen, Klaus Groes

2018-02-01

Major depressive disorder is a common condition that often includes cognitive dysfunction. A systematic literature review of studies and a network meta-analysis were carried out to assess the relative effect of antidepressants on cognitive dysfunction in major depressive disorder. MEDLINE, Embase, Cochrane, CDSR, and PsychINFO databases; clinical trial registries; and relevant conference abstracts were searched for randomized controlled trials assessing the effects of antidepressants/placebo on cognition. A network meta-analysis comparing antidepressants was conducted using a random effects model. The database search retrieved 11337 citations, of which 72 randomized controlled trials from 103 publications met the inclusion criteria. The review identified 86 cognitive tests assessing the effect of antidepressants on cognitive functioning. However, the Digit Symbol Substitution Test, which targets multiple domains of cognition and is recognized as being sensitive to change, was the only test that was used across 12 of the included randomized controlled trials and that allowed the construction of a stable network suitable for the network meta-analysis. The interventions assessed included selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and other non-selective serotonin reuptake inhibitors/serotonin-norepinephrine reuptake inhibitors. The network meta-analysis using the Digit Symbol Substitution Test showed that vortioxetine was the only antidepressant that improved cognitive dysfunction on the Digit Symbol Substitution Test vs placebo {standardized mean difference: 0.325 (95% CI = 0.120; 0.529, P=.009}. Compared with other antidepressants, vortioxetine was statistically more efficacious on the Digit Symbol Substitution Test vs escitalopram, nortriptyline, and the selective serotonin reuptake inhibitor and tricyclic antidepressant classes. This study highlighted the large variability in measures used to assess cognitive functioning. The findings on the Digit Symbol Substitution Test indicate differential effects of various antidepressants on improving cognitive function in patients with major depressive disorder. © The Author 2017. Published by Oxford University Press on behalf of CINP.

Compression embedding

DOEpatents

Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

1998-07-07

A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique are disclosed. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%. 21 figs.

Compression embedding

DOEpatents

Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

1998-01-01

A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%.

Development of the Pipe Loop System for Determining Effectiveness of Corrosion Control Chemicals in Potable Water Systems

DTIC Science & Technology

1988-08-01

OFFICE SYMBOL 7a NAME OF MONITORING ORGANIZATION U.S. Army Construction (if applicable) Engr Research Laboratory CECER-EN 6c. ADDRESS (City, State...and ZIP Code) 7b ADDRESS (City, State, and ZIP Code) P.O. Box 4005 Champaign, IL 61821 8a. NAME OF FUNDING/SPONSORING 8b OFFICE SYMBOL 9 PROCUREMENT...NAME OF RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Include Area Code) 22c OFFICE SYMBOL Jane Andrew 1(217) 352-6511, x388 CECER-IMT DD FORM 1473. 84 MAR 83

Toward a Model Framework of Generalized Parallel Componential Processing of Multi-Symbol Numbers

ERIC Educational Resources Information Center

Huber, Stefan; Cornelsen, Sonja; Moeller, Korbinian; Nuerk, Hans-Christoph

2015-01-01

In this article, we propose and evaluate a new model framework of parallel componential multi-symbol number processing, generalizing the idea of parallel componential processing of multi-digit numbers to the case of negative numbers by considering the polarity signs similar to single digits. In a first step, we evaluated this account by defining…

Intranasal Insulin for Improving Cognitive Function in Multiple Sclerosis

DTIC Science & Technology

2017-10-01

Insulin, Symbol Digit Modalities Test , Minimal Assessment of Cognitive Function in Multiple Sclerosis 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...going to evaluate if intranasal insulin improves cognition in people with MS, as assessed by standardized cognitive assessment tests . 2. KEYWORDS...Multiple Sclerosis, Cognitive Impairment, Neurodegenerative diseases, Intranasal Insulin, Symbol Digit Modalities Test , Minimal Assessment of Cognitive

Effective declutter of complex flight displays using stereoptic 3-D cueing

NASA Technical Reports Server (NTRS)

Parrish, Russell V.; Williams, Steven P.; Nold, Dean E.

1994-01-01

The application of stereo technology to new, integrated pictorial display formats has been effective in situational awareness enhancements, and stereo has been postulated to be effective for the declutter of complex informational displays. This paper reports a full-factorial workstation experiment performed to verify the potential benefits of stereo cueing for the declutter function in a simulated tracking task. The experimental symbology was designed similar to that of a conventional flight director, although the format was an intentionally confused presentation that resulted in a very cluttered dynamic display. The subject's task was to use a hand controller to keep a tracking symbol, an 'X', on top of a target symbol, another X, which was being randomly driven. In the basic tracking task, both the target symbol and the tracking symbol were presented as red X's. The presence of color coding was used to provide some declutter, thus making the task more reasonable to perform. For this condition, the target symbol was coded red, and the tracking symbol was coded blue. Noise conditions, or additional clutter, were provided by the inclusion of randomly moving, differently colored X symbols. Stereo depth, which was hypothesized to declutter the display, was utilized by placing any noise in a plane in front of the display monitor, the tracking symbol at screen depth, and the target symbol behind the screen. The results from analyzing the performances of eight subjects revealed that the stereo presentation effectively offsets the cluttering effects of both the noise and the absence of color coding. The potential of stereo cueing to declutter complex informational displays has therefore been verified; this ability to declutter is an additional benefit from the application of stereoptic cueing to pictorial flight displays.

VLSI single-chip (255,223) Reed-Solomon encoder with interleaver

NASA Technical Reports Server (NTRS)

Hsu, In-Shek (Inventor); Deutsch, Leslie J. (Inventor); Truong, Trieu-Kie (Inventor); Reed, Irving S. (Inventor)

1990-01-01

The invention relates to a concatenated Reed-Solomon/convolutional encoding system consisting of a Reed-Solomon outer code and a convolutional inner code for downlink telemetry in space missions, and more particularly to a Reed-Solomon encoder with programmable interleaving of the information symbols and code correction symbols to combat error bursts in the Viterbi decoder.

Seamless data-range change using punctured convolutional codes for time-varying signal-to-noise ratios

NASA Technical Reports Server (NTRS)

Feria, Y.; Cheung, K.-M.

1995-01-01

In a time-varying signal-to-noise ration (SNR) environment, symbol rate is often changed to maximize data return. However, the symbol-rate change has some undesirable effects, such as changing the transmission bandwidth and perhaps causing the receiver symbol loop to lose lock temporarily, thus losing some data. In this article, we are proposing an alternate way of varying the data rate without changing the symbol rate and, therefore, the transmission bandwidth. The data rate change is achieved in a seamless fashion by puncturing the convolutionally encoded symbol stream to adapt to the changing SNR environment. We have also derived an exact expression to enumerate the number of distinct puncturing patterns. To demonstrate this seamless rate change capability, we searched for good puncturing patterns for the Galileo (14,1/4) convolutional code and changed the data rates by using the punctured codes to match the Galileo SNR profile of November 9, 1997. We show that this scheme reduces the symbol-rate changes from nine to two and provides a comparable data return in a day and a higher symbol SNR during most of the day.

Seamless Data-Rate Change Using Punctured Convolutional Codes for Time-Varying Signal-to-Noise Ratios

NASA Astrophysics Data System (ADS)

Feria, Y.; Cheung, K.-M.

1994-10-01

In a time-varying signal-to-noise ratio (SNR) environment, symbol rate is often changed to maximize data return. However, the symbol-rate change has some undesirable effects, such as changing the transmission bandwidth and perhaps causing the receiver symbol loop to lose lock temporarily, thus losing some data. In this article, we are proposing an alternate way of varying the data rate without changing the symbol rate and, therefore, the transmission bandwidth. The data rate change is achieved in a seamless fashion by puncturing the convolutionally encoded symbol stream to adapt to the changing SNR environment. We have also derived an exact expression to enumerate the number of distinct puncturing patterns. To demonstrate this seamless rate-change capability, we searched for good puncturing patterns for the Galileo (14,1/4) convolutional code and changed the data rates by using the punctured codes to match the Galileo SNR profile of November 9, 1997. We show that this scheme reduces the symbol-rate changes from nine to two and provides a comparable data return in a day and a higher symbol SNR during most of the day.

Seamless data-range change using punctured convolutional codes for time-varying signal-to-noise ratios

NASA Astrophysics Data System (ADS)

Feria, Y.; Cheung, K.-M.

1995-02-01

In a time-varying signal-to-noise ration (SNR) environment, symbol rate is often changed to maximize data return. However, the symbol-rate change has some undesirable effects, such as changing the transmission bandwidth and perhaps causing the receiver symbol loop to lose lock temporarily, thus losing some data. In this article, we are proposing an alternate way of varying the data rate without changing the symbol rate and, therefore, the transmission bandwidth. The data rate change is achieved in a seamless fashion by puncturing the convolutionally encoded symbol stream to adapt to the changing SNR environment. We have also derived an exact expression to enumerate the number of distinct puncturing patterns. To demonstrate this seamless rate change capability, we searched for good puncturing patterns for the Galileo (14,1/4) convolutional code and changed the data rates by using the punctured codes to match the Galileo SNR profile of November 9, 1997. We show that this scheme reduces the symbol-rate changes from nine to two and provides a comparable data return in a day and a higher symbol SNR during most of the day.

Association between basic numerical abilities and mathematics achievement.

PubMed

Sasanguie, Delphine; De Smedt, Bert; Defever, Emmy; Reynvoet, Bert

2012-06-01

Various measures have been used to investigate number processing in children, including a number comparison or a number line estimation task. The present study aimed to examine whether and to which extent these different measures of number representation are related to performance on a curriculum-based standardized mathematics achievement test in kindergarteners, first, second, and sixth graders. Children completed a number comparison task and a number line estimation task with a balanced set of symbolic (Arabic digits) and non-symbolic (dot patterns) stimuli. Associations with mathematics achievement were observed for the symbolic measures. Although the association with number line estimation was consistent over grades, the association with number comparison was much stronger in kindergarten compared to the other grades. The current data indicate that a good knowledge of the numerical meaning of Arabic digits is important for children's mathematical development and that particularly the access to the numerical meaning of symbolic digits rather than the representation of number per se is important. © 2011 The British Psychological Society.

Qualitatively different coding of symbolic and nonsymbolic numbers in the human brain.

PubMed

Lyons, Ian M; Ansari, Daniel; Beilock, Sian L

2015-02-01

Are symbolic and nonsymbolic numbers coded differently in the brain? Neuronal data indicate that overlap in numerical tuning curves is a hallmark of the approximate, analogue nature of nonsymbolic number representation. Consequently, patterns of fMRI activity should be more correlated when the representational overlap between two numbers is relatively high. In bilateral intraparietal sulci (IPS), for nonsymbolic numbers, the pattern of voxelwise correlations between pairs of numbers mirrored the amount of overlap in their tuning curves under the assumption of approximate, analogue coding. In contrast, symbolic numbers showed a flat field of modest correlations more consistent with discrete, categorical representation (no systematic overlap between numbers). Directly correlating activity patterns for a given number across formats (e.g., the numeral "6" with six dots) showed no evidence of shared symbolic and nonsymbolic number-specific representations. Overall (univariate) activity in bilateral IPS was well fit by the log of the number being processed for both nonsymbolic and symbolic numbers. IPS activity is thus sensitive to numerosity regardless of format; however, the nature in which symbolic and nonsymbolic numbers are encoded is fundamentally different. © 2014 Wiley Periodicals, Inc.

Local statistics adaptive entropy coding method for the improvement of H.26L VLC coding

NASA Astrophysics Data System (ADS)

Yoo, Kook-yeol; Kim, Jong D.; Choi, Byung-Sun; Lee, Yung Lyul

2000-05-01

In this paper, we propose an adaptive entropy coding method to improve the VLC coding efficiency of H.26L TML-1 codec. First of all, we will show that the VLC coding presented in TML-1 does not satisfy the sibling property of entropy coding. Then, we will modify the coding method into the local statistics adaptive one to satisfy the property. The proposed method based on the local symbol statistics dynamically changes the mapping relationship between symbol and bit pattern in the VLC table according to sibling property. Note that the codewords in the VLC table of TML-1 codec is not changed. Since this changed mapping relationship also derived in the decoder side by using the decoded symbols, the proposed VLC coding method does not require any overhead information. The simulation results show that the proposed method gives about 30% and 37% reduction in average bit rate for MB type and CBP information, respectively.

Joint Carrier-Phase Synchronization and LDPC Decoding

NASA Technical Reports Server (NTRS)

Simon, Marvin; Valles, Esteban

2009-01-01

A method has been proposed to increase the degree of synchronization of a radio receiver with the phase of a suppressed carrier signal modulated with a binary- phase-shift-keying (BPSK) or quaternary- phase-shift-keying (QPSK) signal representing a low-density parity-check (LDPC) code. This method is an extended version of the method described in Using LDPC Code Constraints to Aid Recovery of Symbol Timing (NPO-43112), NASA Tech Briefs, Vol. 32, No. 10 (October 2008), page 54. Both methods and the receiver architectures in which they would be implemented belong to a class of timing- recovery methods and corresponding receiver architectures characterized as pilotless in that they do not require transmission and reception of pilot signals. The proposed method calls for the use of what is known in the art as soft decision feedback to remove the modulation from a replica of the incoming signal prior to feeding this replica to a phase-locked loop (PLL) or other carrier-tracking stage in the receiver. Soft decision feedback refers to suitably processed versions of intermediate results of iterative computations involved in the LDPC decoding process. Unlike a related prior method in which hard decision feedback (the final sequence of decoded symbols) is used to remove the modulation, the proposed method does not require estimation of the decoder error probability. In a basic digital implementation of the proposed method, the incoming signal (having carrier phase theta theta (sub c) plus noise would first be converted to inphase (I) and quadrature (Q) baseband signals by mixing it with I and Q signals at the carrier frequency [wc/(2 pi)] generated by a local oscillator. The resulting demodulated signals would be processed through one-symbol-period integrate and- dump filters, the outputs of which would be sampled and held, then multiplied by a soft-decision version of the baseband modulated signal. The resulting I and Q products consist of terms proportional to the cosine and sine of the carrier phase cc as well as correlated noise components. These products would be fed as inputs to a digital PLL that would include a number-controlled oscillator (NCO), which provides an estimate of the carrier phase, theta(sub c).

The Wechsler Digit Symbol Substitution Test as the best indicator of the risk of impaired driving in Alzheimer disease and normal aging.

PubMed

Lafont, Sylviane; Marin-Lamellet, Claude; Paire-Ficout, Laurence; Thomas-Anterion, Catherine; Laurent, Bernard; Fabrigoule, Colette

2010-01-01

Our purpose was to identify cognitive tools associated with unsafe driving among elderly drivers of varying cognitive levels. Twenty drivers with early-stage dementia of the Alzheimer type and 56 nondemented drivers aged 65-85 were recruited. Various cognitive processes were measured and unsafe driving was evaluated during an in-traffic road test with 3 different indicators and a composite indicator. The Wechsler Digit Symbol Substitution Test score was the best cognitive measure to detect unsafe drivers using the composite driving indicator. The Digit Symbol Substitution Test may be used by physicians for the evaluation and follow-up of older patients, with or without Alzheimer-type dementia, as a screening tool of unsafe driving.

Data-derived symbol synchronization of MASK and QASK signals. [for multilevel digital communication systems

NASA Technical Reports Server (NTRS)

Simon, M. K.

1974-01-01

Multilevel amplitude-shift-keying (MASK) and quadrature amplitude-shift-keying (QASK) as signaling techniques for multilevel digital communications systems, and the problem of providing symbol synchronization in the receivers of such systems are discussed. A technique is presented for extracting symbol sync from an MASK or QASK signal. The scheme is a generalization of the data transition tracking loop used in PSK systems. The performance of the loop was analyzed in terms of its mean-squared jitter and its effects on the data detection process in MASK and QASK systems.

Exploratory Experimental Investigation of a Wave Propeller

DTIC Science & Technology

1992-03-01

ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION Naval Postgraduate School (if appl able) Naval Postgraduate School 6c. ADDRESS (City... SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (ff applicable) Bc ADDRESS (City, State, and ZIP Code) 10- SOURCE OF FUNDING...UNCLASSIFIED 22a. NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area code) 22c. OFFICE SYMBOL Max F. Platter (408) 646-2058 AA/PL DD FORM 1473,84

A catalog of graphic symbols used at maintenance control centers : toward a symbol standardization process.

DOT National Transportation Integrated Search

2002-04-01

This document catalogs the symbols presented with the various interfaces used by Federal Aviation Administration Airway Facilities specialists. It includes a high-level overview of each system and the symbols and coding conventions used. These data w...

Effects of synthetic speech output in the learning of graphic symbols of varied iconicity.

PubMed

Koul, Rajinder; Schlosser, Ralf

To examine the effects of additional auditory feedback from synthetic speech on the learning of high translucent symbols versus low translucent symbols. Two adults with little or no functional speech and severe intellectual disabilities served as participants. A single-subject ABACA/ACABA design was used to study the relative effects of two treatments: symbol training in the presence and absence of synthetic speech output. The results clearly indicated that the two treatments, rather than extraneous variables were responsible for gains in the symbol learning. Both participants learned either more low translucent symbols or reached their maximum learning of low translucent symbols in the speech output condition. The results of this preliminary study replicate and extend the iconicity hypothesis to a new set of learning conditions involving speech output, and suggest that feedback from speech output may assist adults with profound intellectual disabilities in coding particularly those symbols whose association with their referent cannot be coded via their visual resemblance with the referent.

Cockpit displays of traffic information: Airline pilots opinions about content, symbology, and format

NASA Technical Reports Server (NTRS)

Hart, S. G.; Wempe, T. E.

1979-01-01

A number of candidate computer-generated cockpit displays of traffic information (CDTI) displays and display options were simulated statically and were shown to 23 airline pilots who were asked to respond to more than 250 questions about them. The pilots indicated that the amount and complexity of navigation information displayed should increase with altitude and map scale. Terrain information should appear automatically if a pilot's own aircraft descends below the minimum safe altitude and should include only those obstruction within 2,000 ft or less. Few pilots that weather information should be displayed on a CDTI, but if it was, it should be at pilot request only. A chevron-shaped symbol, located so that the majority of the map area was ahead was preferred. The position, altitude, ground speed, ground track, weight class, and flightpath history of other aircraft should be presented graphically by coding the shape of the symbol for other aircraft or presented digitally in data tags displayed at pilot request. All pilots thought that color coding was necessary to recognize different categories of information quickly and accurately. The majority of pilots felt that a CDTI would provide useful information even though its presence might increase their workload somewhat particularly during its introductory stages.

Spectral analysis of variable-length coded digital signals

NASA Astrophysics Data System (ADS)

Cariolaro, G. L.; Pierobon, G. L.; Pupolin, S. G.

1982-05-01

A spectral analysis is conducted for a variable-length word sequence by an encoder driven by a stationary memoryless source. A finite-state sequential machine is considered as a model of the line encoder, and the spectral analysis of the encoded message is performed under the assumption that the sourceword sequence is composed of independent identically distributed words. Closed form expressions for both the continuous and discrete parts of the spectral density are derived in terms of the encoder law and sourceword statistics. The jump part exhibits jumps at multiple integers of per lambda(sub 0)T, where lambda(sub 0) is the greatest common divisor of the possible codeword lengths, and T is the symbol period. The derivation of the continuous part can be conveniently factorized, and the theory is applied to the spectral analysis of BnZS and HDBn codes.

Single-digit Arabic numbers do not automatically activate magnitude representations in adults or in children: Evidence from the symbolic same–different task☆

PubMed Central

Wong, Becky; Szücs, Dénes

2013-01-01

We investigated whether the mere presentation of single-digit Arabic numbers activates their magnitude representations using a visually-presented symbolic same–different task for 20 adults and 15 children. Participants saw two single-digit Arabic numbers on a screen and judged whether the numbers were the same or different. We examined whether reaction time in this task was primarily driven by (objective or subjective) perceptual similarity, or by the numerical difference between the two digits. We reasoned that, if Arabic numbers automatically activate magnitude representations, a numerical function would best predict reaction time; but if Arabic numbers do not automatically activate magnitude representations, a perceptual function would best predict reaction time. Linear regressions revealed that a perceptual function, specifically, subjective visual similarity, was the best and only significant predictor of reaction time in adults and in children. These data strongly suggest that, in this task, single-digit Arabic numbers do not necessarily automatically activate magnitude representations in adults or in children. As the first study to date to explicitly study the developmental importance of perceptual factors in the symbolic same–different task, we found no significant differences between adults and children in their reliance on perceptual information in this task. Based on our findings, we propose that visual properties may play a key role in symbolic number judgements. PMID:24076332

Is Life Unique?

PubMed Central

Abel, David L.

2011-01-01

Is life physicochemically unique? No. Is life unique? Yes. Life manifests innumerable formalisms that cannot be generated or explained by physicodynamics alone. Life pursues thousands of biofunctional goals, not the least of which is staying alive. Neither physicodynamics, nor evolution, pursue goals. Life is largely directed by linear digital programming and by the Prescriptive Information (PI) instantiated particularly into physicodynamically indeterminate nucleotide sequencing. Epigenomic controls only compound the sophistication of these formalisms. Life employs representationalism through the use of symbol systems. Life manifests autonomy, homeostasis far from equilibrium in the harshest of environments, positive and negative feedback mechanisms, prevention and correction of its own errors, and organization of its components into Sustained Functional Systems (SFS). Chance and necessity—heat agitation and the cause-and-effect determinism of nature’s orderliness—cannot spawn formalisms such as mathematics, language, symbol systems, coding, decoding, logic, organization (not to be confused with mere self-ordering), integration of circuits, computational success, and the pursuit of functionality. All of these characteristics of life are formal, not physical. PMID:25382119

Bandwidth tunable microwave photonic filter based on digital and analog modulation

NASA Astrophysics Data System (ADS)

Zhang, Qi; Zhang, Jie; Li, Qiang; Wang, Yubing; Sun, Xian; Dong, Wei; Zhang, Xindong

2018-05-01

A bandwidth tunable microwave photonic filter based on digital and analog modulation is proposed and experimentally demonstrated. The digital modulation is used to broaden the effective gain spectrum and the analog modulation is to get optical lines. By changing the symbol rate of data pattern, the bandwidth is tunable from 50 MHz to 700 MHz. The interval of optical lines is set according to the bandwidth of gain spectrum which is related to the symbol rate. Several times of bandwidth increase are achieved compared to a single analog modulation and the selectivity of the response is increased by 3.7 dB compared to a single digital modulation.

Speech processing using conditional observable maximum likelihood continuity mapping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hogden, John; Nix, David

A computer implemented method enables the recognition of speech and speech characteristics. Parameters are initialized of first probability density functions that map between the symbols in the vocabulary of one or more sequences of speech codes that represent speech sounds and a continuity map. Parameters are also initialized of second probability density functions that map between the elements in the vocabulary of one or more desired sequences of speech transcription symbols and the continuity map. The parameters of the probability density functions are then trained to maximize the probabilities of the desired sequences of speech-transcription symbols. A new sequence ofmore » speech codes is then input to the continuity map having the trained first and second probability function parameters. A smooth path is identified on the continuity map that has the maximum probability for the new sequence of speech codes. The probability of each speech transcription symbol for each input speech code can then be output.« less

Executive functioning and processing speed in age-related differences in memory: contribution of a coding task.

PubMed

Baudouin, Alexia; Clarys, David; Vanneste, Sandrine; Isingrini, Michel

2009-12-01

The aim of the present study was to examine executive dysfunctioning and decreased processing speed as potential mediators of age-related differences in episodic memory. We compared the performances of young and elderly adults in a free-recall task. Participants were also given tests to measure executive functions and perceptual processing speed and a coding task (the Digit Symbol Substitution Test, DSST). More precisely, we tested the hypothesis that executive functions would mediate the age-related differences observed in the free-recall task better than perceptual speed. We also tested the assumption that a coding task, assumed to involve both executive processes and perceptual speed, would be the best mediator of age-related differences in memory. Findings first confirmed that the DSST combines executive processes and perceptual speed. Secondly, they showed that executive functions are a significant mediator of age-related differences in memory, and that DSST performance is the best predictor.

Performance of DBS-Radio using concatenated coding and equalization

NASA Technical Reports Server (NTRS)

Gevargiz, J.; Bell, D.; Truong, L.; Vaisnys, A.; Suwitra, K.; Henson, P.

1995-01-01

The Direct Broadcast Satellite-Radio (DBS-R) receiver is being developed for operation in a multipath Rayleigh channel. This receiver uses equalization and concatenated coding, in addition to open loop and closed loop architectures for carrier demodulation and symbol synchronization. Performance test results of this receiver are presented in both AWGN and multipath Rayleigh channels. Simulation results show that the performance of the receiver operating in a multipath Rayleigh channel is significantly improved by using equalization. These results show that fractional-symbol equalization offers a performance advantage over full symbol equalization. Also presented is the base-line performance of the DBS-R receiver using concatenated coding and interleaving.

File compression and encryption based on LLS and arithmetic coding

NASA Astrophysics Data System (ADS)

Yu, Changzhi; Li, Hengjian; Wang, Xiyu

2018-03-01

e propose a file compression model based on arithmetic coding. Firstly, the original symbols, to be encoded, are input to the encoder one by one, we produce a set of chaotic sequences by using the Logistic and sine chaos system(LLS), and the values of this chaotic sequences are randomly modified the Upper and lower limits of current symbols probability. In order to achieve the purpose of encryption, we modify the upper and lower limits of all character probabilities when encoding each symbols. Experimental results show that the proposed model can achieve the purpose of data encryption while achieving almost the same compression efficiency as the arithmetic coding.

Instruments for Reading Direct-Marked Data-Matrix Symbols

NASA Technical Reports Server (NTRS)

Schramm, Harry F.; Corder, Eric L.

2006-01-01

Improved optoelectronic instruments (specially configured digital cameras) for reading direct-marked data-matrix symbols on the surfaces of optically reflective objects (including specularly reflective ones) are undergoing development. Data-matrix symbols are two-dimensional binary patterns that are used, like common bar codes, for automated identification of objects. The first data-matrix symbols were checkerboard-like patterns of black-and-white rectangles, typically existing in the forms of paint, ink, or detachable labels. The major advantage of direct marking (the marks are more durable than are painted or printed symbols or detachable labels) is offset by a major disadvantage (the marks generated by some marking methods do not provide sufficient contrast to be readable by optoelectronic instruments designed to read black-and-white data-matrix symbols). Heretofore, elaborate lighting, lensing, and software schemes have been tried in efforts to solve the contrast problem in direct-mark matrix- symbol readers. In comparison with prior readers based on those schemes, the readers now undergoing development are expected to be more effective while costing less. All of the prior direct-mark matrix-symbol readers are designed to be aimed perpendicularly to marked target surfaces, and they tolerate very little angular offset. However, the reader now undergoing development not only tolerates angular offset but depends on angular offset as a means of obtaining the needed contrast, as described below. The prototype reader (see Figure 1) includes an electronic camera in the form of a charge-coupled-device (CCD) image detector equipped with a telecentric lens. It also includes a source of collimated visible light and a source of collimated infrared light for illuminating a target. The visible and infrared illumination complement each other: the visible illumination is more useful for aiming the reader toward a target, while the infrared illumination is more useful for reading symbols on highly reflective surfaces. By use of beam splitters, the visible and infrared collimated lights are introduced along the optical path of the telecentric lens, so that the target is illuminated and viewed from the same direction.

Performance of the split-symbol moments SNR estimator in the presence of inter-symbol interference

NASA Technical Reports Server (NTRS)

Shah, B.; Hinedi, S.

1989-01-01

The Split-Symbol Moments Estimator (SSME) is an algorithm that is designed to estimate symbol signal-to-noise ratio (SNR) in the presence of additive white Gaussian noise (AWGN). The performance of the SSME algorithm in band-limited channels is examined. The effects of the resulting inter-symbol interference (ISI) are quantified. All results obtained are in closed form and can be easily evaluated numerically for performance prediction purposes. Furthermore, they are validated through digital simulations.

Benefit from NASA

NASA Image and Video Library

1995-01-01

Digital data matrix, used to identify the millions of Space Shuttle parts, is being commercialized to make barcoding tamper resistant and invisible to the naked eye. These codes are applied directly to the product regardless of shape, size or color. The markings can range from as small as four microns to as large as two square feet. Using the Vericode Symbol which include such details as the manufacturer, serial numbers, the lot number of the parent material, design changes, special processing to which the part was subjected-everything needed to determine accurately and automatically, the extent of the recall needed, which might be a couple of hundred cars instead of tens of thousands.

Children’s Mapping between Non-Symbolic and Symbolic Numerical Magnitudes and Its Association with Timed and Untimed Tests of Mathematics Achievement

PubMed Central

Brankaer, Carmen; Ghesquière, Pol; De Smedt, Bert

2014-01-01

The ability to map between non-symbolic numerical magnitudes and Arabic numerals has been put forward as a key factor in children’s mathematical development. This mapping ability has been mainly examined indirectly by looking at children’s performance on a symbolic magnitude comparison task. The present study investigated mapping in a more direct way by using a task in which children had to choose which of two choice quantities (Arabic digits or dot arrays) matched the target quantity (dot array or Arabic digit), thereby focusing on small quantities ranging from 1 to 9. We aimed to determine the development of mapping over time and its relation to mathematics achievement. Participants were 36 first graders (M = 6 years 8 months) and 46 third graders (M = 8 years 8 months) who all completed mapping tasks, symbolic and non-symbolic magnitude comparison tasks and standardized timed and untimed tests of mathematics achievement. Findings revealed that children are able to map between non-symbolic and symbolic representations and that this mapping ability develops over time. Moreover, we found that children’s mapping ability is related to timed and untimed measures of mathematics achievement, over and above the variance accounted for by their numerical magnitude comparison skills. PMID:24699664

Norm comparisons of the Spanish-language and English-language WAIS-III: Implications for clinical assessment and test adaptation.

PubMed

Funes, Cynthia M; Rodriguez, Juventino Hernandez; Lopez, Steven Regeser

2016-12-01

This study provides a systematic comparison of the norms of 3 Spanish-language Wechsler Adult Intelligence Scales (WAIS-III) batteries from Mexico, Spain, and Puerto Rico, and the U.S. English-language WAIS-III battery. Specifically, we examined the performance of the 4 normative samples on 2 identical subtests (Digit Span and Digit Symbol-Coding) and 1 nearly identical subtest (Block Design). We found that across most age groups the means associated with the Spanish-language versions of the 3 subtests were lower than the means of the U.S. English-language version. In addition, we found that for most age ranges the Mexican subsamples scored lower than the Spanish subsamples. Lower educational levels of Mexicans and Spaniards compared to U.S. residents are consistent with the general pattern of findings. These results suggest that because of the different norms, applying any of the 3 Spanish-language versions of the WAIS-III generally risks underestimating deficits, and that applying the English-language WAIS-III norms risks overestimating deficits of Spanish-speaking adults. There were a few exceptions to these general patterns. For example, the Mexican subsample ages 70 years and above performed significantly better on the Digit Symbol and Block Design than did the U.S. and Spanish subsamples. Implications for the clinical assessment of U.S. Spanish-speaking Latinos and test adaptation are discussed with an eye toward improving the clinical care for this community. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Performance of the all-digital data-transition tracking loop in the advanced receiver

NASA Astrophysics Data System (ADS)

Cheng, U.; Hinedi, S.

1989-11-01

The performance of the all-digital data-transition tracking loop (DTTL) with coherent or noncoherent sampling is described. The effects of few samples per symbol and of noncommensurate sampling rates and symbol rates are addressed and analyzed. Their impacts on the loop phase-error variance and the mean time to lose lock (MTLL) are quantified through computer simulations. The analysis and preliminary simulations indicate that with three to four samples per symbol, the DTTL can track with negligible jitter because of the presence of earth Doppler rate. Furthermore, the MTLL is also expected to be large engough to maintain lock over a Deep Space Network track.

Improved sensitivity of the rapid screen of mild traumatic brain injury.

PubMed

De Monte, Veronica Eileen; Geffen, Gina Malke; May, Christopher Randall; McFarland, Ken

2010-01-01

This study aimed to investigate the acute effects of mild traumatic brain injury (mTBI) in an emergency department sample. A total of 246 (186 male, 60 female) cases of mTBI and 102 (65 male and 37 female) cases of orthopedic injuries were tested within 24 hours of injury. Mild TBI patients performed more poorly on all subtests of the Rapid Screen of Concussion (RSC) and completed fewer symbols on Digit Symbol than did orthopedic controls. RSC scores predicted group membership better than chance, and Digit Symbol scores contributed significantly to predicting group membership over and above the contribution of the RSC, resulting in 70.4% sensitivity and 74% specificity for the extended protocol. The results of this study indicate that learning and memory, orientation, and speed of information processing are impaired immediately following mTBI. Furthermore, a brief battery of tests that include word recall, orientation, and the Digit Symbol Substitution Test could assess the severity of dysfunction following mTBI, and assist in clinical decision making regarding discharge, return to routine activities, and management of the effects of injury.

Programmable noise bandwidth reduction by means of digital averaging

NASA Technical Reports Server (NTRS)

Poklemba, John J. (Inventor)

1993-01-01

Predetection noise bandwidth reduction is effected by a pre-averager capable of digitally averaging the samples of an input data signal over two or more symbols, the averaging interval being defined by the input sampling rate divided by the output sampling rate. As the averaged sample is clocked to a suitable detector at a much slower rate than the input signal sampling rate the noise bandwidth at the input to the detector is reduced, the input to the detector having an improved signal to noise ratio as a result of the averaging process, and the rate at which such subsequent processing must operate is correspondingly reduced. The pre-averager forms a data filter having an output sampling rate of one sample per symbol of received data. More specifically, selected ones of a plurality of samples accumulated over two or more symbol intervals are output in response to clock signals at a rate of one sample per symbol interval. The pre-averager includes circuitry for weighting digitized signal samples using stored finite impulse response (FIR) filter coefficients. A method according to the present invention is also disclosed.

Multiple Trellis Coded Modulation (MTCM): An MSAT-X report

NASA Technical Reports Server (NTRS)

Divsalar, D.; Simon, M. K.

1986-01-01

Conventional trellis coding outputs one channel symbol per trellis branch. The notion of multiple trellis coding is introduced wherein more than one channel symbol per trellis branch is transmitted. It is shown that the combination of multiple trellis coding with M-ary modulation yields a performance gain with symmetric signal set comparable to that previously achieved only with signal constellation asymmetry. The advantage of multiple trellis coding over the conventional trellis coded asymmetric modulation technique is that the potential for code catastrophe associated with the latter has been eliminated with no additional cost in complexity (as measured by the number of states in the trellis diagram).

On the symbolic manipulation and code generation for elasto-plastic material matrices

NASA Technical Reports Server (NTRS)

Chang, T. Y.; Saleeb, A. F.; Wang, P. S.; Tan, H. Q.

1991-01-01

A computerized procedure for symbolic manipulations and FORTRAN code generation of an elasto-plastic material matrix for finite element applications is presented. Special emphasis is placed on expression simplifications during intermediate derivations, optimal code generation, and interface with the main program. A systematic procedure is outlined to avoid redundant algebraic manipulations. Symbolic expressions of the derived material stiffness matrix are automatically converted to RATFOR code which is then translated into FORTRAN statements through a preprocessor. To minimize the interface problem with the main program, a template file is prepared so that the translated FORTRAN statements can be merged into the file to form a subroutine (or a submodule). Three constitutive models; namely, von Mises plasticity, Drucker-Prager model, and a concrete plasticity model, are used as illustrative examples.

Separable concatenated codes with iterative map decoding for Rician fading channels

NASA Technical Reports Server (NTRS)

Lodge, J. H.; Young, R. J.

1993-01-01

Very efficient signalling in radio channels requires the design of very powerful codes having special structure suitable for practical decoding schemes. In this paper, powerful codes are obtained by combining comparatively simple convolutional codes to form multi-tiered 'separable' convolutional codes. The decoding of these codes, using separable symbol-by-symbol maximum a posteriori (MAP) 'filters', is described. It is known that this approach yields impressive results in non-fading additive white Gaussian noise channels. Interleaving is an inherent part of the code construction, and consequently, these codes are well suited for fading channel communications. Here, simulation results for communications over Rician fading channels are presented to support this claim.

Single-digit Arabic numbers do not automatically activate magnitude representations in adults or in children: evidence from the symbolic same-different task.

PubMed

Wong, Becky; Szücs, Dénes

2013-11-01

We investigated whether the mere presentation of single-digit Arabic numbers activates their magnitude representations using a visually-presented symbolic same-different task for 20 adults and 15 children. Participants saw two single-digit Arabic numbers on a screen and judged whether the numbers were the same or different. We examined whether reaction time in this task was primarily driven by (objective or subjective) perceptual similarity, or by the numerical difference between the two digits. We reasoned that, if Arabic numbers automatically activate magnitude representations, a numerical function would best predict reaction time; but if Arabic numbers do not automatically activate magnitude representations, a perceptual function would best predict reaction time. Linear regressions revealed that a perceptual function, specifically, subjective visual similarity, was the best and only significant predictor of reaction time in adults and in children. These data strongly suggest that, in this task, single-digit Arabic numbers do not necessarily automatically activate magnitude representations in adults or in children. As the first study to date to explicitly study the developmental importance of perceptual factors in the symbolic same-different task, we found no significant differences between adults and children in their reliance on perceptual information in this task. Based on our findings, we propose that visual properties may play a key role in symbolic number judgements. © 2013. Published by Elsevier B.V. All rights reserved.

Handwritten mathematical symbols dataset.

PubMed

Chajri, Yassine; Bouikhalene, Belaid

2016-06-01

Due to the technological advances in recent years, paper scientific documents are used less and less. Thus, the trend in the scientific community to use digital documents has increased considerably. Among these documents, there are scientific documents and more specifically mathematics documents. In this context, we present our own dataset of handwritten mathematical symbols composed of 10,379 images. This dataset gathers Arabic characters, Latin characters, Arabic numerals, Latin numerals, arithmetic operators, set-symbols, comparison symbols, delimiters, etc.

Symbolic magnitude processing in elementary school children: A group administered paper-and-pencil measure (SYMP Test).

PubMed

Brankaer, Carmen; Ghesquière, Pol; De Smedt, Bert

2017-08-01

The ability to compare symbolic numerical magnitudes correlates with children's concurrent and future mathematics achievement. We developed and evaluated a quick timed paper-and-pencil measure that can easily be used, for example in large-scale research, in which children have to cross out the numerically larger of two Arabic one- and two-digit numbers (SYMP Test). We investigated performance on this test in 1,588 primary school children (Grades 1-6) and examined in each grade its associations with mathematics achievement. The SYMP Test had satisfactory test-retest reliability. The SYMP Test showed significant and stable correlations with mathematics achievement for both one-digit and two-digit comparison, across all grades. This replicates the previously observed association between symbolic numerical magnitude processing and mathematics achievement, but extends it by showing that the association is observed in all grades in primary education and occurs for single- as well as multi-digit processing. Children with mathematical learning difficulties performed significantly lower on one-digit comparison and two-digit comparison in all grades. This all suggests satisfactory construct and criterion-related validity of the SYMP Test, which can be used in research, when performing large-scale (intervention) studies, and by practitioners, as screening measure to identify children at risk for mathematical difficulties or dyscalculia.

Hand-Held Ultrasonic Instrument for Reading Matrix Symbols

NASA Technical Reports Server (NTRS)

Schramm, Harry F.; Kula, John P.; Gurney, John W.; Lior, Ephraim D.

2008-01-01

A hand-held instrument that would include an ultrasonic camera has been proposed as an efficient means of reading matrix symbols. The proposed instrument could be operated without mechanical raster scanning. All electronic functions from excitation of ultrasonic pulses through final digital processing for decoding matrix symbols would be performed by dedicated circuitry within the single, compact instrument housing.

Teaching Reading to the Disadvantaged Adult.

ERIC Educational Resources Information Center

Dinnan, James A.; Ulmer, Curtis, Ed.

This manual is designed to assess the background of the individual and to bring him to the stage of unlocking the symbolic codes called Reading and Mathematics. The manual begins with Introduction to a Symbolic Code (The Thinking Process and The Key to Learning Basis), and continues with Basic Reading Skills (Readiness, Visual Discrimination,…

Symbolic Speech

ERIC Educational Resources Information Center

Podgor, Ellen S.

1976-01-01

The concept of symbolic speech emanates from the 1967 case of United States v. O'Brien. These discussions of flag desecration, grooming and dress codes, nude entertainment, buttons and badges, and musical expression show that the courts place symbolic speech in different strata from verbal communication. (LBH)

Development of the Average Likelihood Function for Code Division Multiple Access (CDMA) Using BPSK and QPSK Symbols

DTIC Science & Technology

2015-01-01

This research has the purpose to establish a foundation for new classification and estimation of CDMA signals. Keywords: DS / CDMA signals, BPSK, QPSK...DEVELOPMENT OF THE AVERAGE LIKELIHOOD FUNCTION FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) USING BPSK AND QPSK SYMBOLS JANUARY 2015...To) OCT 2013 – OCT 2014 4. TITLE AND SUBTITLE DEVELOPMENT OF THE AVERAGE LIKELIHOOD FUNCTION FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) USING BPSK

Handwritten mathematical symbols dataset

PubMed Central

Chajri, Yassine; Bouikhalene, Belaid

2016-01-01

Due to the technological advances in recent years, paper scientific documents are used less and less. Thus, the trend in the scientific community to use digital documents has increased considerably. Among these documents, there are scientific documents and more specifically mathematics documents. In this context, we present our own dataset of handwritten mathematical symbols composed of 10,379 images. This dataset gathers Arabic characters, Latin characters, Arabic numerals, Latin numerals, arithmetic operators, set-symbols, comparison symbols, delimiters, etc. PMID:27006975

A symbolic/subsymbolic interface protocol for cognitive modeling

PubMed Central

Simen, Patrick; Polk, Thad

2009-01-01

Researchers studying complex cognition have grown increasingly interested in mapping symbolic cognitive architectures onto subsymbolic brain models. Such a mapping seems essential for understanding cognition under all but the most extreme viewpoints (namely, that cognition consists exclusively of digitally implemented rules; or instead, involves no rules whatsoever). Making this mapping reduces to specifying an interface between symbolic and subsymbolic descriptions of brain activity. To that end, we propose parameterization techniques for building cognitive models as programmable, structured, recurrent neural networks. Feedback strength in these models determines whether their components implement classically subsymbolic neural network functions (e.g., pattern recognition), or instead, logical rules and digital memory. These techniques support the implementation of limited production systems. Though inherently sequential and symbolic, these neural production systems can exploit principles of parallel, analog processing from decision-making models in psychology and neuroscience to explain the effects of brain damage on problem solving behavior. PMID:20711520

7 CFR 28.525 - Symbols and code numbers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... designations in inches. (a) Symbols and Code numbers used for Color Grades of American Upland Cotton. Color... 41 Low Middling LM 51 Strict Good Ordinary SGO 61 Good Ordinary GO 71 Good Middling Light Spotted GM Lt SP 12 Strict Middling Light Spotted SM Lt Sp 22 Middling Light Spotted Mid Lt Sp 32 Strict Low...

7 CFR 28.525 - Symbols and code numbers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... designations in inches. (a) Symbols and Code numbers used for Color Grades of American Upland Cotton. Color... 41 Low Middling LM 51 Strict Good Ordinary SGO 61 Good Ordinary GO 71 Good Middling Light Spotted GM Lt SP 12 Strict Middling Light Spotted SM Lt Sp 22 Middling Light Spotted Mid Lt Sp 32 Strict Low...

7 CFR 28.525 - Symbols and code numbers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... designations in inches. (a) Symbols and Code numbers used for Color Grades of American Upland Cotton. Color... 41 Low Middling LM 51 Strict Good Ordinary SGO 61 Good Ordinary GO 71 Good Middling Light Spotted GM Lt SP 12 Strict Middling Light Spotted SM Lt Sp 22 Middling Light Spotted Mid Lt Sp 32 Strict Low...

7 CFR 28.525 - Symbols and code numbers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... designations in inches. (a) Symbols and Code numbers used for Color Grades of American Upland Cotton. Color... 41 Low Middling LM 51 Strict Good Ordinary SGO 61 Good Ordinary GO 71 Good Middling Light Spotted GM Lt SP 12 Strict Middling Light Spotted SM Lt Sp 22 Middling Light Spotted Mid Lt Sp 32 Strict Low...

7 CFR 28.525 - Symbols and code numbers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... designations in inches. (a) Symbols and Code numbers used for Color Grades of American Upland Cotton. Color... 41 Low Middling LM 51 Strict Good Ordinary SGO 61 Good Ordinary GO 71 Good Middling Light Spotted GM Lt SP 12 Strict Middling Light Spotted SM Lt Sp 22 Middling Light Spotted Mid Lt Sp 32 Strict Low...

Automatic finite element generators

NASA Technical Reports Server (NTRS)

Wang, P. S.

1984-01-01

The design and implementation of a software system for generating finite elements and related computations are described. Exact symbolic computational techniques are employed to derive strain-displacement matrices and element stiffness matrices. Methods for dealing with the excessive growth of symbolic expressions are discussed. Automatic FORTRAN code generation is described with emphasis on improving the efficiency of the resultant code.

Enhanced decoding for the Galileo S-band mission

NASA Technical Reports Server (NTRS)

Dolinar, S.; Belongie, M.

1993-01-01

A coding system under consideration for the Galileo S-band low-gain antenna mission is a concatenated system using a variable redundancy Reed-Solomon outer code and a (14,1/4) convolutional inner code. The 8-bit Reed-Solomon symbols are interleaved to depth 8, and the eight 255-symbol codewords in each interleaved block have redundancies 64, 20, 20, 20, 64, 20, 20, and 20, respectively (or equivalently, the codewords have 191, 235, 235, 235, 191, 235, 235, and 235 8-bit information symbols, respectively). This concatenated code is to be decoded by an enhanced decoder that utilizes a maximum likelihood (Viterbi) convolutional decoder; a Reed Solomon decoder capable of processing erasures; an algorithm for declaring erasures in undecoded codewords based on known erroneous symbols in neighboring decodable words; a second Viterbi decoding operation (redecoding) constrained to follow only paths consistent with the known symbols from previously decodable Reed-Solomon codewords; and a second Reed-Solomon decoding operation using the output from the Viterbi redecoder and additional erasure declarations to the extent possible. It is estimated that this code and decoder can achieve a decoded bit error rate of 1 x 10(exp 7) at a concatenated code signal-to-noise ratio of 0.76 dB. By comparison, a threshold of 1.17 dB is required for a baseline coding system consisting of the same (14,1/4) convolutional code, a (255,223) Reed-Solomon code with constant redundancy 32 also interleaved to depth 8, a one-pass Viterbi decoder, and a Reed Solomon decoder incapable of declaring or utilizing erasures. The relative gain of the enhanced system is thus 0.41 dB. It is predicted from analysis based on an assumption of infinite interleaving that the coding gain could be further improved by approximately 0.2 dB if four stages of Viterbi decoding and four levels of Reed-Solomon redundancy are permitted. Confirmation of this effect and specification of the optimum four-level redundancy profile for depth-8 interleaving is currently being done.

On the optimality of a universal noiseless coder

NASA Technical Reports Server (NTRS)

Yeh, Pen-Shu; Rice, Robert F.; Miller, Warner H.

1993-01-01

Rice developed a universal noiseless coding structure that provides efficient performance over an extremely broad range of source entropy. This is accomplished by adaptively selecting the best of several easily implemented variable length coding algorithms. Variations of such noiseless coders have been used in many NASA applications. Custom VLSI coder and decoder modules capable of processing over 50 million samples per second have been fabricated and tested. In this study, the first of the code options used in this module development is shown to be equivalent to a class of Huffman code under the Humblet condition, for source symbol sets having a Laplacian distribution. Except for the default option, other options are shown to be equivalent to the Huffman codes of a modified Laplacian symbol set, at specified symbol entropy values. Simulation results are obtained on actual aerial imagery over a wide entropy range, and they confirm the optimality of the scheme. Comparison with other known techniques are performed on several widely used images and the results further validate the coder's optimality.

On the performance of a code division multiple access scheme with transmit/receive conflicts

NASA Astrophysics Data System (ADS)

Silvester, J. A.

One of the benefits of spread spectrum is that by assigning each user a different orthogonal signal set, multiple transmissions can occur simultaneously. This possibility is utilized in new access schemes called Code Division Multiple Access (CDMA). The present investigation is concerned with a particular CDMA implementation in which the transmit times for each symbol are exactly determined in a distributed manner such that both sender and receiver know them. In connection with a decision whether to transmit or receive, the loss of a symbol in one of the channels results. The system employs thus a coding technique which permits correct decoding of a codeword even if some constituent symbols are missing or in error. The technique used is Reed Solomon coding. The performance of this system is analyzed, and attention is given to the optimum strategy which should be used in deciding whether to receive or transmit.

Mathematical difficulties in developmental coordination disorder: Symbolic and nonsymbolic number processing.

PubMed

Gomez, Alice; Piazza, Manuela; Jobert, Antoinette; Dehaene-Lambertz, Ghislaine; Dehaene, Stanislas; Huron, Caroline

2015-01-01

At school, children with Developmental Coordination Disorder (DCD) struggle with mathematics. However, little attention has been paid to their numerical cognition abilities. The goal of this study was to better understand the cognitive basis for mathematical difficulties in children with DCD. Twenty 7-to-10 years-old children with DCD were compared to twenty age-matched typically developing children using dot and digit comparison tasks to assess symbolic and nonsymbolic number processing and in a task of single digits additions. Results showed that children with DCD had lower performance in nonsymbolic and symbolic number comparison tasks than typically developing children. They were also slower to solve simple addition problems. Moreover, correlational analyses showed that children with DCD who experienced greater impairments in the nonsymbolic task also performed more poorly in the symbolic tasks. These findings suggest that DCD impairs both nonsymbolic and symbolic number processing. A systematic assessment of numerical cognition in children with DCD could provide a more comprehensive picture of their deficits and help in proposing specific remediation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coded DS-CDMA Systems with Iterative Channel Estimation and no Pilot Symbols

DTIC Science & Technology

2010-08-01

ar X iv :1 00 8. 31 96 v1 [ cs .I T ] 1 9 A ug 2 01 0 1 Coded DS - CDMA Systems with Iterative Channel Estimation and no Pilot Symbols Don...sequence code-division multiple-access ( DS - CDMA ) systems with quadriphase-shift keying in which channel estimation, coherent demodulation, and decoding...amplitude, phase, and the interference power spectral density (PSD) due to the combined interference and thermal noise is proposed for DS - CDMA systems

Pilotless Frame Synchronization Using LDPC Code Constraints

NASA Technical Reports Server (NTRS)

Jones, Christopher; Vissasenor, John

2009-01-01

A method of pilotless frame synchronization has been devised for low- density parity-check (LDPC) codes. In pilotless frame synchronization , there are no pilot symbols; instead, the offset is estimated by ex ploiting selected aspects of the structure of the code. The advantag e of pilotless frame synchronization is that the bandwidth of the sig nal is reduced by an amount associated with elimination of the pilot symbols. The disadvantage is an increase in the amount of receiver data processing needed for frame synchronization.

Reading Through Paint

NASA Technical Reports Server (NTRS)

2004-01-01

Two-dimensional data matrix symbols, which contain encoded letters and numbers, are permanently etched on items for identification. They can store up to 100 times more information than traditional bar codes. While the symbols provide several advantages over bar codes, once they are covered by paint they can no longer be read by optical scanners. Since most products are painted eventually, this presents a problem for industries relying on the symbols for identification and tracking. In 1987, NASA s Marshall Space Flight Center began studying direct parts marking with matrix symbols in order to track millions of Space Shuttle parts. Advances in the technology proved that by incorporating magnetic properties into the paints, inks, and pastes used to apply the matrix symbols, the codes could be read by a magnetic scanner even after being covered with paint or other coatings. NASA received a patent for such a scanner in 1998, but the system it used for development was not portable and was too costly. A prototype was needed as a lead-in to a production model. In the summer of 2000, NASA began seeking companies to build a hand-held scanner that would detect the Read Through Paint data matrix identification marks containing magnetic materials through coatings.

INSTRUMENTATION AND CONTROLS DIVISION, ELECTRICAL DESIGN STANDARDS AND GRAPHICAL SYMBOLS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bates, A.E.G.; Bowelle, M.M.; Horton, J.L.

1960-10-01

Recommendations of the Instrumentation and Controls Division Committee on Electrical and Electronic Symbols and Drawings are presented. The American Standards Associrtion Graphical Symbols for Electrical Diagrams are given, with certain variations or additions recommended by the Committee to clarify or more positively identify the device or element symbolized. Recommendations regarding electrical elementary diagram 1ayout, device coding, etc., are included. (W.D.M.)

Northwest range-plant symbols adapted to automatic data processing.

Treesearch

George A. Garrison; Jon M. Skovlin

1960-01-01

Many range technicians, agronomists, foresters, biologists, and botanists of various educational institutions and government agencies in the Northwest have been using a four-letter symbol list or code compiled 12 years ago from records of plants collected by the U.S. Forest Service in Oregon and Washington, This code has served well as a means of entering plant names...

The fast decoding of Reed-Solomon codes using number theoretic transforms

NASA Technical Reports Server (NTRS)

Reed, I. S.; Welch, L. R.; Truong, T. K.

1976-01-01

It is shown that Reed-Solomon (RS) codes can be encoded and decoded by using a fast Fourier transform (FFT) algorithm over finite fields. The arithmetic utilized to perform these transforms requires only integer additions, circular shifts and a minimum number of integer multiplications. The computing time of this transform encoder-decoder for RS codes is less than the time of the standard method for RS codes. More generally, the field GF(q) is also considered, where q is a prime of the form K x 2 to the nth power + 1 and K and n are integers. GF(q) can be used to decode very long RS codes by an efficient FFT algorithm with an improvement in the number of symbols. It is shown that a radix-8 FFT algorithm over GF(q squared) can be utilized to encode and decode very long RS codes with a large number of symbols. For eight symbols in GF(q squared), this transform over GF(q squared) can be made simpler than any other known number theoretic transform with a similar capability. Of special interest is the decoding of a 16-tuple RS code with four errors.

MACSYMA's symbolic ordinary differential equation solver

NASA Technical Reports Server (NTRS)

Golden, J. P.

1977-01-01

The MACSYMA's symbolic ordinary differential equation solver ODE2 is described. The code for this routine is delineated, which is of interest because it is written in top-level MACSYMA language, and may serve as a good example of programming in that language. Other symbolic ordinary differential equation solvers are mentioned.

Symbol lock detection implemented with nonoverlapping integration intervals

NASA Technical Reports Server (NTRS)

Shihabi, Mazen M. (Inventor); Hinedi, Sami M. (Inventor); Shah, Biren N. (Inventor)

1995-01-01

A symbol lock detector is introduced for an incoming coherent digital communication signal which utilizes a subcarrier modulated with binary symbol data, d(sub k), and known symbol interval T by integrating binary values of the signal over nonoverlapping first and second intervals selected to be T/2, delaying the first integral an interval T/2, and either summing or multiplying the second integral with the first one that preceded it to form a value X(sub k). That value is then averaged over a number M of symbol intervals to produce a static value Y. A symbol lock decision can then be made when the static value Y exceeds a threshold level delta.

Sample-Clock Phase-Control Feedback

NASA Technical Reports Server (NTRS)

Quirk, Kevin J.; Gin, Jonathan W.; Nguyen, Danh H.; Nguyen, Huy

2012-01-01

To demodulate a communication signal, a receiver must recover and synchronize to the symbol timing of a received waveform. In a system that utilizes digital sampling, the fidelity of synchronization is limited by the time between the symbol boundary and closest sample time location. To reduce this error, one typically uses a sample clock in excess of the symbol rate in order to provide multiple samples per symbol, thereby lowering the error limit to a fraction of a symbol time. For systems with a large modulation bandwidth, the required sample clock rate is prohibitive due to current technological barriers and processing complexity. With precise control of the phase of the sample clock, one can sample the received signal at times arbitrarily close to the symbol boundary, thus obviating the need, from a synchronization perspective, for multiple samples per symbol. Sample-clock phase-control feedback was developed for use in the demodulation of an optical communication signal, where multi-GHz modulation bandwidths would require prohibitively large sample clock frequencies for rates in excess of the symbol rate. A custom mixedsignal (RF/digital) offset phase-locked loop circuit was developed to control the phase of the 6.4-GHz clock that samples the photon-counting detector output. The offset phase-locked loop is driven by a feedback mechanism that continuously corrects for variation in the symbol time due to motion between the transmitter and receiver as well as oscillator instability. This innovation will allow significant improvements in receiver throughput; for example, the throughput of a pulse-position modulation (PPM) with 16 slots can increase from 188 Mb/s to 1.5 Gb/s.

Cross-cultural comparison of neurobehavioral performance in Asian workers.

PubMed

Chung, Jong-Hak; Sakong, Joon; Kang, Pock-Soo; Kim, Chang-Yoon; Lee, Kyeong-Soo; Jeon, Man-Joong; Sung, Nak-Jung; Ahn, Sang-Ho; Won, Kyu-Chang

2003-08-01

Widely-used neurobehavioral tests have been developed and standardized on Western populations, but studies on subject factors for Asian populations have been very limited. For the effective application and interpretation of neurobehavioral tests in Asian populations, an evaluation of the effects of subject factors, including cultural background, is necessary. A cross-cultural study was conducted to evaluate the effects of cultural background and the interaction between cultural background and education on neurobehavioral tests in Asian populations. The Korean version of the Swedish Performance Evaluation System (Simple Reaction Time, Symbol Digit, and Finger Tapping Speed) and a pegboard test were administered to 537 workers who were not exposed to chemicals at work from Fareast (Korea and Chinese), Central (Uzbekistan and Tajikistan), and South Asia (Sri Lanka and Indonesia). The Fareast Asian group exhibited better performance in adjusted test scores than other Asian groups, achieving significance for Symbol Digit and Finger Tapping Speed in both genders. The magnitude of the effect of cultural background on Symbol Digit was comparable to the effect of about 10 years of education. Cultural background did not modify the relation between years of education and Symbol Digit in either males or females. This study may provide the first evidence that cultural background has a large impact on neurobehavioral test performance, even within Asian populations, and suggests that cultural background is a critical confounding factor that must be controlled in epidemiologic studies which include Asian populations in the sample.

Performance analysis of the word synchronization properties of the outer code in a TDRSS decoder

NASA Technical Reports Server (NTRS)

Costello, D. J., Jr.; Lin, S.

1984-01-01

A self-synchronizing coding scheme for NASA's TDRSS satellite system is a concatenation of a (2,1,7) inner convolutional code with a (255,223) Reed-Solomon outer code. Both symbol and word synchronization are achieved without requiring that any additional symbols be transmitted. An important parameter which determines the performance of the word sync procedure is the ratio of the decoding failure probability to the undetected error probability. Ideally, the former should be as small as possible compared to the latter when the error correcting capability of the code is exceeded. A computer simulation of a (255,223) Reed-Solomon code as carried out. Results for decoding failure probability and for undetected error probability are tabulated and compared.

The LIFE Cognition Study: design and baseline characteristics

PubMed Central

Sink, Kaycee M; Espeland, Mark A; Rushing, Julia; Castro, Cynthia M; Church, Timothy S; Cohen, Ronald; Gill, Thomas M; Henkin, Leora; Jennings, Janine M; Kerwin, Diana R; Manini, Todd M; Myers, Valerie; Pahor, Marco; Reid, Kieran F; Woolard, Nancy; Rapp, Stephen R; Williamson, Jeff D

2014-01-01

Observational studies have shown beneficial relationships between exercise and cognitive function. Some clinical trials have also demonstrated improvements in cognitive function in response to moderate–high intensity aerobic exercise; however, these have been limited by relatively small sample sizes and short durations. The Lifestyle Interventions and Independence for Elders (LIFE) Study is the largest and longest randomized controlled clinical trial of physical activity with cognitive outcomes, in older sedentary adults at increased risk for incident mobility disability. One LIFE Study objective is to evaluate the effects of a structured physical activity program on changes in cognitive function and incident all-cause mild cognitive impairment or dementia. Here, we present the design and baseline cognitive data. At baseline, participants completed the modified Mini Mental Status Examination, Hopkins Verbal Learning Test, Digit Symbol Coding, Modified Rey–Osterrieth Complex Figure, and a computerized battery, selected to be sensitive to changes in speed of processing and executive functioning. During follow up, participants completed the same battery, along with the Category Fluency for Animals, Boston Naming, and Trail Making tests. The description of the mild cognitive impairment/dementia adjudication process is presented here. Participants with worse baseline Short Physical Performance Battery scores (prespecified at ≤7) had significantly lower median cognitive test scores compared with those having scores of 8 or 9 with modified Mini Mental Status Examination score of 91 versus (vs) 93, Hopkins Verbal Learning Test delayed recall score of 7.4 vs 7.9, and Digit Symbol Coding score of 45 vs 48, respectively (all P<0.001). The LIFE Study will contribute important information on the effects of a structured physical activity program on cognitive outcomes in sedentary older adults at particular risk for mobility impairment. In addition to its importance in the area of prevention of cognitive decline, the LIFE Study will also likely serve as a model for exercise and other behavioral intervention trials in older adults. PMID:25210447

A human performance evaluation of graphic symbol-design features.

PubMed

Samet, M G; Geiselman, R E; Landee, B M

1982-06-01

16 subjects learned each of two tactical display symbol sets (conventional symbols and iconic symbols) in turn and were then shown a series of graphic displays containing various symbol configurations. For each display, the subject was asked questions corresponding to different behavioral processes relating to symbol use (identification, search, comparison, pattern recognition). The results indicated that: (a) conventional symbols yielded faster pattern-recognition performance than iconic symbols, and iconic symbols did not yield faster identification than conventional symbols, and (b) the portrayal of additional feature information (through the use of perimeter density or vector projection coding) slowed processing of the core symbol information in four tasks, but certain symbol-design features created less perceptual interference and had greater correspondence with the portrayal of specific tactical concepts than others. The results were discussed in terms of the complexities involved in the selection of symbol design features for use in graphic tactical displays.

[Computer graphic display of retinal examination results. Software improving the quality of documenting fundus changes].

PubMed

Jürgens, Clemens; Grossjohann, Rico; Czepita, Damian; Tost, Frank

2009-01-01

Graphic documentation of retinal examination results in clinical ophthalmological practice is often depicted using pictures or in handwritten form. Popular software products used to describe changes in the fundus do not vary much from simple graphic programs that enable to insert, scale and edit basic graphic elements such as: a circle, rectangle, arrow or text. Displaying the results of retinal examinations in a unified way is difficult to achieve. Therefore, we devised and implemented modern software tools for this purpose. A computer program enabling to quickly and intuitively form graphs of the fundus, that can be digitally archived or printed was created. Especially for the needs of ophthalmological clinics, a set of standard digital symbols used to document the results of retinal examinations was developed and installed in a library of graphic symbols. These symbols are divided into the following categories: preoperative, postoperative, neovascularization, retinopathy of prematurity. The appropriate symbol can be selected with a click of the mouse and dragged-and-dropped on the canvas of the fundus. Current forms of documenting results of retinal examinations are unsatisfactory, due to the fact that they are time consuming and imprecise. Unequivocal interpretation is difficult or in some cases impossible. Using the developed computer program a sketch of the fundus can be created much more quickly than by hand drawing. Additionally the quality of the medica documentation using a system of well described and standardized symbols will be enhanced. (1) Graphic symbols used to document the results of retinal examinations are a part of everyday clinical practice. (2) The designed computer program will allow quick and intuitive graphical creation of fundus sketches that can be either digitally archived or printed.

[Spanish normative studies in a young adult population (NEURONORMA young adults Project): norms for the verbal span, visuospatial span, Letter-Number Sequencing, Trail Making Test and Symbol Digit Modalities Test].

PubMed

Tamayo, F; Casals-Coll, M; Sánchez-Benavides, G; Quintana, M; Manero, R M; Rognoni, T; Calvo, L; Palomo, R; Aranciva, F; Peña-Casanova, J

2012-01-01

Verbal and visuospatial span, Letter-Number Sequencing, Trail Making Test, and Symbol Digit Modalities Test are frequently used in clinical practice to assess attention, executive functions and memory. In the present study, as part of the Spanish normative studies of NEURONORMA young adults Project, normative data adjusted by age and education are provided for digits, Corsi Block-Tapping Task, Letter-Number Sequencing, Trail Making Test, and Symbol Digit Modalities Test. The sample consisted of 179 participants from 18 to 49 years old, who were cognitively normal. Tables to convert raw scores to scaled scores are provided. Age and education adjusted scores are provided by applying linear regressions. Education affected scores in most of the attention tests; age was found to be related to the visuospatial span and to speed of visuomotor tracking, and there was no relationship as regards sex. The data obtained will be useful in the clinical evaluation of young Spanish adults. Copyright © 2011 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

Research in Optical Symbolic Tasks

DTIC Science & Technology

1989-11-29

November 1989. Specifically, we have concentrated on the following topics: complexity studies for optical neural and digital systems, architecture and...1989. Specifically, we hav, concentrated on the following topics: complexity studies for optical neural and digital systems, architecture and models for...Digital Systems 1.1 Digital Optical Parallel System Complexity Our study of digital optical system complexity has included a comparison of optical and

Efficient Bit-to-Symbol Likelihood Mappings

NASA Technical Reports Server (NTRS)

Moision, Bruce E.; Nakashima, Michael A.

2010-01-01

This innovation is an efficient algorithm designed to perform bit-to-symbol and symbol-to-bit likelihood mappings that represent a significant portion of the complexity of an error-correction code decoder for high-order constellations. Recent implementation of the algorithm in hardware has yielded an 8- percent reduction in overall area relative to the prior design.

The Face-Symbol Test and the Symbol-Digit Test are not reliable surrogates for the Paced Auditory Serial Addition Test in multiple sclerosis.

PubMed

Williams, J; O'Rourke, K; Hutchinson, M; Tubridy, N

2006-10-01

The Paced Auditory Serial Addition Test (PASAT) is the chosen task for cognitive assessment in the multiple sclerosis functional composite (MSFC) and a widely used task in neuropsychological studies of people with multiple sclerosis (MS), but is unpopular with patients. The Face-Symbol Test (FST) and Symbol-Digit Tests (SDT) are alternative methods of cognitive testing in MS, which are easily administered and patient-friendly. In order to evaluate the potential of the FST as a possible surrogate for the PASAT, we directly compared the FST to the PASAT and the SDT in a cohort of 50 MS patients with varying levels of disability. There was significant correlation between SDT and FST scores (Spearman's rho 0.80, 95% CI 0.66-0.88), R(2) 65%, with moderate inter-test agreement (k =0.52). In contrast, SDT and FST scores were less predictive of PASAT scores. We concluded that neither the FST nor SDT are reliable surrogates for the PASAT.

Advanced Receiver For Phase-Shift-Keyed Signals

NASA Technical Reports Server (NTRS)

Hinedi, Sami M.

1992-01-01

ARX II is second "breadboard" version of advanced receiver, a hybrid digital/analog receiving subsystem, extracting symbols and Doppler shifts from weak phase-shift-keyed signals. Useful in terrestrial digital communication systems.

Multiple trellis coded modulation

NASA Technical Reports Server (NTRS)

Simon, Marvin K. (Inventor); Divsalar, Dariush (Inventor)

1990-01-01

A technique for designing trellis codes to minimize bit error performance for a fading channel. The invention provides a criteria which may be used in the design of such codes which is significantly different from that used for average white Gaussian noise channels. The method of multiple trellis coded modulation of the present invention comprises the steps of: (a) coding b bits of input data into s intermediate outputs; (b) grouping said s intermediate outputs into k groups of s.sub.i intermediate outputs each where the summation of all s.sub.i,s is equal to s and k is equal to at least 2; (c) mapping each of said k groups of intermediate outputs into one of a plurality of symbols in accordance with a plurality of modulation schemes, one for each group such that the first group is mapped in accordance with a first modulation scheme and the second group is mapped in accordance with a second modulation scheme; and (d) outputting each of said symbols to provide k output symbols for each b bits of input data.

Serial turbo trellis coded modulation using a serially concatenated coder

NASA Technical Reports Server (NTRS)

Divsalar, Dariush (Inventor); Dolinar, Samuel J. (Inventor); Pollara, Fabrizio (Inventor)

2010-01-01

Serial concatenated trellis coded modulation (SCTCM) includes an outer coder, an interleaver, a recursive inner coder and a mapping element. The outer coder receives data to be coded and produces outer coded data. The interleaver permutes the outer coded data to produce interleaved data. The recursive inner coder codes the interleaved data to produce inner coded data. The mapping element maps the inner coded data to a symbol. The recursive inner coder has a structure which facilitates iterative decoding of the symbols at a decoder system. The recursive inner coder and the mapping element are selected to maximize the effective free Euclidean distance of a trellis coded modulator formed from the recursive inner coder and the mapping element. The decoder system includes a demodulation unit, an inner SISO (soft-input soft-output) decoder, a deinterleaver, an outer SISO decoder, and an interleaver.

Definite Integrals, Some Involving Residue Theory Evaluated by Maple Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowman, Kimiko o

2010-01-01

The calculus of residue is applied to evaluate certain integrals in the range (-{infinity} to {infinity}) using the Maple symbolic code. These integrals are of the form {integral}{sub -{infinity}}{sup {infinity}} cos(x)/[(x{sup 2} + a{sup 2})(x{sup 2} + b{sup 2}) (x{sup 2} + c{sup 2})]dx and similar extensions. The Maple code is also applied to expressions in maximum likelihood estimator moments when sampling from the negative binomial distribution. In general the Maple code approach to the integrals gives correct answers to specified decimal places, but the symbolic result may be extremely long and complex.

Formal hardware verification of digital circuits

NASA Technical Reports Server (NTRS)

Joyce, J.; Seger, C.-J.

1991-01-01

The use of formal methods to verify the correctness of digital circuits is less constrained by the growing complexity of digital circuits than conventional methods based on exhaustive simulation. This paper briefly outlines three main approaches to formal hardware verification: symbolic simulation, state machine analysis, and theorem-proving.

The relationships between pesticide metabolites and neurobehavioral test performance in the third National Health and Nutrition Examination Survey.

PubMed

Krieg, Edward F

2013-01-01

Regression analysis was used to estimate and test for relationships between urinary pesticide metabolites and neurobehavioral test performance in adults, 20 to 59 years old, participating in the third National Health and Nutrition Examination Survey. The 12 pesticide metabolites included 2 naphthols, 8 phenols, a phenoxyacetic acid, and a pyridinol. The 3 neurobehavioral tests included in the survey were simple reaction time, symbol-digit substitution, and serial digit learning. As the 2,4-dichlorophenol, 2,5-dichlorophenol, and the pentachlorophenol concentrations increased, performance on the serial digit learning test improved. As the 2,5-dichlorophenol concentration increased, performance on the symbol-digit substitution test improved. At low concentrations, the parent compounds of these metabolites may act at acetylcholine and γ-aminobutyric acid synapses in the central nervous system to improve neurobehavioral test performance.

Designing learning apparatus to promote twelfth grade students’ understanding of digital technology concept: A preliminary studies

NASA Astrophysics Data System (ADS)

Marlius; Kaniawati, I.; Feranie, S.

2018-05-01

A preliminary learning design using relay to promote twelfth grade student’s understanding of logic gates concept is implemented to see how well it’s to adopted by six high school students, three male students and three female students of twelfth grade. This learning design is considered for next learning of digital technology concept i.e. data digital transmition and analog. This work is a preliminary study to design the learning for large class. So far just a few researches designing learning design related to digital technology with relay. It may due to this concept inserted in Indonesian twelfth grade curriculum recently. This analysis is focus on student difficulties trough video analysis to learn the concept. Based on our analysis, the recommended thing for redesigning learning is: students understand first about symbols and electrical circuits; the Student Worksheet is made in more detail on the assembly steps to the project board; mark with symbols at points in certain places in the circuit for easy assembly; assembly using relays by students is enough until is the NOT’s logic gates and the others that have been assembled so that effective time. The design of learning using relays can make the relay a liaison between the abstract on the digital with the real thing of it, especially in the circuit of symbols and real circuits. Besides it is expected to also enrich the ability of teachers in classroom learning about digital technology.

Modified hybrid subcarrier/amplitude/ phase/polarization LDPC-coded modulation for 400 Gb/s optical transmission and beyond.

PubMed

Batshon, Hussam G; Djordjevic, Ivan; Xu, Lei; Wang, Ting

2010-06-21

In this paper, we present a modified coded hybrid subcarrier/ amplitude/phase/polarization (H-SAPP) modulation scheme as a technique capable of achieving beyond 400 Gb/s single-channel transmission over optical channels. The modified H-SAPP scheme profits from the available resources in addition to geometry to increase the bandwidth efficiency of the transmission system, and so increases the aggregate rate of the system. In this report we present the modified H-SAPP scheme and focus on an example that allows 11 bits/Symbol that can achieve 440 Gb/s transmission using components of 50 Giga Symbol/s (GS/s).

Code-Time Diversity for Direct Sequence Spread Spectrum Systems

PubMed Central

Hassan, A. Y.

2014-01-01

Time diversity is achieved in direct sequence spread spectrum by receiving different faded delayed copies of the transmitted symbols from different uncorrelated channel paths when the transmission signal bandwidth is greater than the coherence bandwidth of the channel. In this paper, a new time diversity scheme is proposed for spread spectrum systems. It is called code-time diversity. In this new scheme, N spreading codes are used to transmit one data symbol over N successive symbols interval. The diversity order in the proposed scheme equals to the number of the used spreading codes N multiplied by the number of the uncorrelated paths of the channel L. The paper represents the transmitted signal model. Two demodulators structures will be proposed based on the received signal models from Rayleigh flat and frequency selective fading channels. Probability of error in the proposed diversity scheme is also calculated for the same two fading channels. Finally, simulation results are represented and compared with that of maximal ration combiner (MRC) and multiple-input and multiple-output (MIMO) systems. PMID:24982925

Implementation and Evaluation of Microcomputer Systems for the Republic of Turkey’s Naval Ships.

DTIC Science & Technology

1986-03-01

important database design tool for both logical and physical database design, such as flowcharts or pseudocodes are used for program design. Logical...string manipulation in FORTRAN is difficult but not impossible. BASIC ( Beginners All-Purpose Symbolic Instruction Code): Basic is currently the most...63 APPENDIX B GLOSSARY/ACRONYM LIST AC Alternating Current AP Application Program BASIC Beginners All-purpose Symbolic Instruction Code CCP

Sociomaterial Texts, Spaces and Devices: Questioning "Digital Dualism" in Library and Study Practices

ERIC Educational Resources Information Center

Gourlay, Lesley; Lanclos, Donna M.; Oliver, Martin

2015-01-01

Work on students' study practices posits the digital and material as separate domains, with the "digital" assumed to be disembodied, decontextualised and free-floating, and spaces in the material campus positioned as prototypically "traditional" and analogue. Libraries in particular are often characterised as symbolic of…

Adaptive frequency-domain equalization in digital coherent optical receivers.

PubMed

Faruk, Md Saifuddin; Kikuchi, Kazuro

2011-06-20

We propose a novel frequency-domain adaptive equalizer in digital coherent optical receivers, which can reduce computational complexity of the conventional time-domain adaptive equalizer based on finite-impulse-response (FIR) filters. The proposed equalizer can operate on the input sequence sampled by free-running analog-to-digital converters (ADCs) at the rate of two samples per symbol; therefore, the arbitrary initial sampling phase of ADCs can be adjusted so that the best symbol-spaced sequence is produced. The equalizer can also be configured in the butterfly structure, which enables demultiplexing of polarization tributaries apart from equalization of linear transmission impairments. The performance of the proposed equalization scheme is verified by 40-Gbits/s dual-polarization quadrature phase-shift keying (QPSK) transmission experiments.

Read-Write-Codes: An Erasure Resilient Encoding System for Flexible Reading and Writing in Storage Networks

NASA Astrophysics Data System (ADS)

Mense, Mario; Schindelhauer, Christian

We introduce the Read-Write-Coding-System (RWC) - a very flexible class of linear block codes that generate efficient and flexible erasure codes for storage networks. In particular, given a message x of k symbols and a codeword y of n symbols, an RW code defines additional parameters k ≤ r,w ≤ n that offer enhanced possibilities to adjust the fault-tolerance capability of the code. More precisely, an RWC provides linear left(n,k,dright)-codes that have (a) minimum distance d = n - r + 1 for any two codewords, and (b) for each codeword there exists a codeword for each other message with distance of at most w. Furthermore, depending on the values r,w and the code alphabet, different block codes such as parity codes (e.g. RAID 4/5) or Reed-Solomon (RS) codes (if r = k and thus, w = n) can be generated. In storage networks in which I/O accesses are very costly and redundancy is crucial, this flexibility has considerable advantages as r and w can optimally be adapted to read or write intensive applications; only w symbols must be updated if the message x changes completely, what is different from other codes which always need to rewrite y completely as x changes. In this paper, we first state a tight lower bound and basic conditions for all RW codes. Furthermore, we introduce special RW codes in which all mentioned parameters are adjustable even online, that is, those RW codes are adaptive to changing demands. At last, we point out some useful properties regarding safety and security of the stored data.

Developmental specialization of the left parietal cortex for the semantic representation of Arabic numerals: an fMR-adaptation study.

PubMed

Vogel, Stephan E; Goffin, Celia; Ansari, Daniel

2015-04-01

The way the human brain constructs representations of numerical symbols is poorly understood. While increasing evidence from neuroimaging studies has indicated that the intraparietal sulcus (IPS) becomes increasingly specialized for symbolic numerical magnitude representation over developmental time, the extent to which these changes are associated with age-related differences in symbolic numerical magnitude representation or with developmental changes in non-numerical processes, such as response selection, remains to be uncovered. To address these outstanding questions we investigated developmental changes in the cortical representation of symbolic numerical magnitude in 6- to 14-year-old children using a passive functional magnetic resonance imaging adaptation design, thereby mitigating the influence of response selection. A single-digit Arabic numeral was repeatedly presented on a computer screen and interspersed with the presentation of novel digits deviating as a function of numerical ratio (smaller/larger number). Results demonstrated a correlation between age and numerical ratio in the left IPS, suggesting an age-related increase in the extent to which numerical symbols are represented in the left IPS. Brain activation of the right IPS was modulated by numerical ratio but did not correlate with age, indicating hemispheric differences in IPS engagement during the development of symbolic numerical representation. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Multiple-Symbol Noncoherent Decoding of Uncoded and Convolutionally Codes Continous Phase Modulation

NASA Technical Reports Server (NTRS)

Divsalar, D.; Raphaeli, D.

2000-01-01

Recently, a method for combined noncoherent detection and decoding of trellis-codes (noncoherent coded modulation) has been proposed, which can practically approach the performance of coherent detection.

Performance analysis of a cascaded coding scheme with interleaved outer code

NASA Technical Reports Server (NTRS)

Lin, S.

1986-01-01

A cascaded coding scheme for a random error channel with a bit-error rate is analyzed. In this scheme, the inner code C sub 1 is an (n sub 1, m sub 1l) binary linear block code which is designed for simultaneous error correction and detection. The outer code C sub 2 is a linear block code with symbols from the Galois field GF (2 sup l) which is designed for correcting both symbol errors and erasures, and is interleaved with a degree m sub 1. A procedure for computing the probability of a correct decoding is presented and an upper bound on the probability of a decoding error is derived. The bound provides much better results than the previous bound for a cascaded coding scheme with an interleaved outer code. Example schemes with inner codes ranging from high rates to very low rates are evaluated. Several schemes provide extremely high reliability even for very high bit-error rates say 10 to the -1 to 10 to the -2 power.

A modified non-binary LDPC scheme based on watermark symbols in high speed optical transmission systems

NASA Astrophysics Data System (ADS)

Wang, Liming; Qiao, Yaojun; Yu, Qian; Zhang, Wenbo

2016-04-01

We introduce a watermark non-binary low-density parity check code (NB-LDPC) scheme, which can estimate the time-varying noise variance by using prior information of watermark symbols, to improve the performance of NB-LDPC codes. And compared with the prior-art counterpart, the watermark scheme can bring about 0.25 dB improvement in net coding gain (NCG) at bit error rate (BER) of 1e-6 and 36.8-81% reduction of the iteration numbers. Obviously, the proposed scheme shows great potential in terms of error correction performance and decoding efficiency.

On the optimality of code options for a universal noiseless coder

NASA Technical Reports Server (NTRS)

Yeh, Pen-Shu; Rice, Robert F.; Miller, Warner

1991-01-01

A universal noiseless coding structure was developed that provides efficient performance over an extremely broad range of source entropy. This is accomplished by adaptively selecting the best of several easily implemented variable length coding algorithms. Custom VLSI coder and decoder modules capable of processing over 20 million samples per second are currently under development. The first of the code options used in this module development is shown to be equivalent to a class of Huffman code under the Humblet condition, other options are shown to be equivalent to the Huffman codes of a modified Laplacian symbol set, at specified symbol entropy values. Simulation results are obtained on actual aerial imagery, and they confirm the optimality of the scheme. On sources having Gaussian or Poisson distributions, coder performance is also projected through analysis and simulation.

Application and Expansion of the Modular Command and Control Evaluation Structure (MCES) as a Framework for Improving Interoperability Management.

DTIC Science & Technology

1987-06-01

DECLASSIFICATION OWNGRAONG SCIEDULE distribution is unlimited. 4 PERFORMING ORGANIATION REPORT NUMBIR(S) S MONITORING ORGANIZATION REPORT NUVBER(S) 6a NAME OF...PERFORMING ORGANIZATION 60 OFFICE SYMBOL 7a NAME OF MONITORING ORGANIZATION (if applicable) Naval Postgraduate SchoolJ Code 74 Naval Postgraduate School 6c...FUNOINGi SPONSORING Sb OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If dappicable) 8c AODRESS (City, State. ard ZIP Code

Construction and Testing of an 80C86 Based Communications Controller for the Petite Amateur Navy Satellite (PANSAT)

DTIC Science & Technology

1990-12-01

S) Naval Postgraduate School 6a. NAME OF PERFORMING ORGANIZATION 6b OFFICE SYMBOL 7a NAME OF MONITORING ORGANIZATION (if applicable ) Code 33 6c...FUNDING/SPONSORING Bb. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable ) 8c. ADDRESS (City, State, and ZIP Code...system’s individual components. Then one derives the overall system reliability from that information, using a simple mathematical model, to be

Bandwidth efficient CCSDS coding standard proposals

NASA Technical Reports Server (NTRS)

Costello, Daniel J., Jr.; Perez, Lance C.; Wang, Fu-Quan

1992-01-01

The basic concatenated coding system for the space telemetry channel consists of a Reed-Solomon (RS) outer code, a symbol interleaver/deinterleaver, and a bandwidth efficient trellis inner code. A block diagram of this configuration is shown. The system may operate with or without the outer code and interleaver. In this recommendation, the outer code remains the (255,223) RS code over GF(2 exp 8) with an error correcting capability of t = 16 eight bit symbols. This code's excellent performance and the existence of fast, cost effective, decoders justify its continued use. The purpose of the interleaver/deinterleaver is to distribute burst errors out of the inner decoder over multiple codewords of the outer code. This utilizes the error correcting capability of the outer code more efficiently and reduces the probability of an RS decoder failure. Since the space telemetry channel is not considered bursty, the required interleaving depth is primarily a function of the inner decoding method. A diagram of an interleaver with depth 4 that is compatible with the (255,223) RS code is shown. Specific interleaver requirements are discussed after the inner code recommendations.

Characterization of a symbol rate timing recovery technique for a 2B1Q digital receiver

NASA Astrophysics Data System (ADS)

Aboulnasr, T.; Hage, M.; Sayar, B.; Aly, S.

1994-02-01

This paper presents a study of several implementations of the Mueller and Muller symbol rate timing recovery algorithm for ISDN transmission over digital subscriber loops (DSL). Implementations of this algorithm using various estimates of a specified timing function are investigated. It will be shown that despite the fact that all of the estimates considered are derived based on one set of conditions, their performance varies widely in a real system. The intrinsic properties of these estimates are first analyzed, then their performance on real subscriber loops is studied through extensive simulations of a practical digital receiver. The effect of various system parameters such as channel distortion and additive noise are included. Possible sources of convergence problems are also identified and corrective action proposed.

Noncoherent Symbol Synchronization Techniques

NASA Technical Reports Server (NTRS)

Simon, Marvin

2005-01-01

Traditional methods for establishing symbol synchronization (sync) in digital communication receivers assume that carrier sync has already been established, i.e., the problem is addressed at the baseband level assuming that a 'perfect' estimate of carrier phase is available. We refer to this approach as coherent symbol sync. Since, for NRZ signaling, a suppressed carrier sync loop such as an I-Q Costas loop includes integrate-and-dump (I and D) filters in its in-phase (1) and quadrature (Q) arms, the traditional approach is to first track the carrier in the absence of symbol sync information, then feed back the symbol sync estimate to these filters, and then iterate between the two to a desirable operating level In this paper, we revisit the symbol sync problem by examining methods for obtaining such sync in the absence of carrier phase information, i.e., so-called noncoherent symbol sync loops. We compare the performance of these loops with that of a well-known coherent symbol sync loop and examine the conditions under which one is preferable over the other.

Count on dopamine: influences of COMT polymorphisms on numerical cognition

PubMed Central

Júlio-Costa, Annelise; Antunes, Andressa M.; Lopes-Silva, Júlia B.; Moreira, Bárbara C.; Vianna, Gabrielle S.; Wood, Guilherme; Carvalho, Maria R. S.; Haase, Vitor G.

2013-01-01

Catechol-O-methyltransferase (COMT) is an enzyme that is particularly important for the metabolism of dopamine. Functional polymorphisms of COMT have been implicated in working memory and numerical cognition. This is an exploratory study that aims at investigating associations between COMT polymorphisms, working memory, and numerical cognition. Elementary school children from 2th to 6th grades were divided into two groups according to their COMT val158met polymorphism [homozygous for valine allele (n = 61) vs. heterozygous plus methionine homozygous children or met+ group (n = 94)]. Both groups were matched for age and intelligence. Working memory was assessed through digit span and Corsi blocks. Symbolic numerical processing was assessed through transcoding and single-digit word problem tasks. Non-symbolic magnitude comparison and estimation tasks were used to assess number sense. Between-group differences were found in symbolic and non-symbolic numerical tasks, but not in working memory tasks. Children in the met+ group showed better performance in all numerical tasks while val homozygous children presented slower development of non-symbolic magnitude representations. These results suggest COMT-related dopaminergic modulation may be related not only to working memory, as found in previous studies, but also to the development of magnitude processing and magnitude representations. PMID:23966969

Trazodone improves sleep parameters in Alzheimer disease patients: a randomized, double-blind, and placebo-controlled study.

PubMed

Camargos, Einstein F; Louzada, Luciana L; Quintas, Juliana L; Naves, Janeth O S; Louzada, Fernando M; Nóbrega, Otávio T

2014-12-01

There are no randomized clinical trials regarding efficacy of trazodone in the treatment of sleep disturbances (SD) in patients with Alzheimer disease (AD). We tested the efficacy and safety of trazodone to treat SD in patients with AD. We conducted a double-blind, randomized and controlled trial during periods of 7-9 days at baseline and 2 weeks of treatment. Geriatric medical center of the university's general hospital. Individuals with probable AD and SD. The complete analysis comprised 30 patients assigned to either the active treatment group (N = 15) or the placebo group (N = 15). Patients received 50 mg of trazodone once daily at 10:00 P.M. or placebo in a 1:1 ratio for 2 weeks. Patients were evaluated using actigraphy and structured scales before and after intervention. Compared with the placebo group, trazodone users slept 42.5 more minutes per night and had their nighttime percent sleep increased 8.5 percentage points according to actigraphic data post-treatment. Neither trazodone nor placebo induced significant daytime sleepiness or naps. The treatments with trazodone or placebo did not show any effects either on cognition (Mini-Mental State Examination, forward/backward digit span task, letter-number sequencing, arithmetic, digit symbol-coding, and symbol search) or functionality (Katz index). There were no differences in frequency or severity rating of adverse events between the groups. This study shows significant therapeutic effects of trazodone 50 mg in community-dwelling AD patients with SD. Copyright © 2014 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Cartographic symbol library considering symbol relations based on anti-aliasing graphic library

NASA Astrophysics Data System (ADS)

Mei, Yang; Li, Lin

2007-06-01

Cartographic visualization represents geographic information with a map form, which enables us retrieve useful geospatial information. In digital environment, cartographic symbol library is the base of cartographic visualization and is an essential component of Geographic Information System as well. Existing cartographic symbol libraries have two flaws. One is the display quality and the other one is relations adjusting. Statistic data presented in this paper indicate that the aliasing problem is a major factor on the symbol display quality on graphic display devices. So, effective graphic anti-aliasing methods based on a new anti-aliasing algorithm are presented and encapsulated in an anti-aliasing graphic library with the form of Component Object Model. Furthermore, cartographic visualization should represent feature relation in the way of correctly adjusting symbol relations besides displaying an individual feature. But current cartographic symbol libraries don't have this capability. This paper creates a cartographic symbol design model to implement symbol relations adjusting. Consequently the cartographic symbol library based on this design model can provide cartographic visualization with relations adjusting capability. The anti-aliasing graphic library and the cartographic symbol library are sampled and the results prove that the two libraries both have better efficiency and effect.

A Golay complementary TS-based symbol synchronization scheme in variable rate LDPC-coded MB-OFDM UWBoF system

NASA Astrophysics Data System (ADS)

He, Jing; Wen, Xuejie; Chen, Ming; Chen, Lin

2015-09-01

In this paper, a Golay complementary training sequence (TS)-based symbol synchronization scheme is proposed and experimentally demonstrated in multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband over fiber (UWBoF) system with a variable rate low-density parity-check (LDPC) code. Meanwhile, the coding gain and spectral efficiency in the variable rate LDPC-coded MB-OFDM UWBoF system are investigated. By utilizing the non-periodic auto-correlation property of the Golay complementary pair, the start point of LDPC-coded MB-OFDM UWB signal can be estimated accurately. After 100 km standard single-mode fiber (SSMF) transmission, at the bit error rate of 1×10-3, the experimental results show that the short block length 64QAM-LDPC coding provides a coding gain of 4.5 dB, 3.8 dB and 2.9 dB for a code rate of 62.5%, 75% and 87.5%, respectively.

Phase ambiguity resolution for offset QPSK modulation systems

NASA Technical Reports Server (NTRS)

Nguyen, Tien M. (Inventor)

1991-01-01

A demodulator for Offset Quaternary Phase Shift Keyed (OQPSK) signals modulated with two words resolves eight possible combinations of phase ambiguity which may produce data error by first processing received I(sub R) and Q(sub R) data in an integrated carrier loop/symbol synchronizer using a digital Costas loop with matched filters for correcting four of eight possible phase lock errors, and then the remaining four using a phase ambiguity resolver which detects the words to not only reverse the received I(sub R) and Q(sub R) data channels, but to also invert (complement) the I(sub R) and/or Q(sub R) data, or to at least complement the I(sub R) and Q(sub R) data for systems using nontransparent codes that do not have rotation direction ambiguity.

Comparison of transform coding methods with an optimal predictor for the data compression of digital elevation models

NASA Technical Reports Server (NTRS)

Lewis, Michael

1994-01-01

Statistical encoding techniques enable the reduction of the number of bits required to encode a set of symbols, and are derived from their probabilities. Huffman encoding is an example of statistical encoding that has been used for error-free data compression. The degree of compression given by Huffman encoding in this application can be improved by the use of prediction methods. These replace the set of elevations by a set of corrections that have a more advantageous probability distribution. In particular, the method of Lagrange Multipliers for minimization of the mean square error has been applied to local geometrical predictors. Using this technique, an 8-point predictor achieved about a 7 percent improvement over an existing simple triangular predictor.

Eye-movement patterns during nonsymbolic and symbolic numerical magnitude comparison and their relation to math calculation skills.

PubMed

Price, Gavin R; Wilkey, Eric D; Yeo, Darren J

2017-05-01

A growing body of research suggests that the processing of nonsymbolic (e.g. sets of dots) and symbolic (e.g. Arabic digits) numerical magnitudes serves as a foundation for the development of math competence. Performance on magnitude comparison tasks is thought to reflect the precision of a shared cognitive representation, as evidence by the presence of a numerical ratio effect for both formats. However, little is known regarding how visuo-perceptual processes are related to the numerical ratio effect, whether they are shared across numerical formats, and whether they relate to math competence independently of performance outcomes. The present study investigates these questions in a sample of typically developing adults. Our results reveal a pattern of associations between eye-movement measures, but not their ratio effects, across formats. This suggests that ratio-specific visuo-perceptual processing during magnitude processing is different across nonsymbolic and symbolic formats. Furthermore, eye movements are related to math performance only during symbolic comparison, supporting a growing body of literature suggesting symbolic number processing is more strongly related to math outcomes than nonsymbolic magnitude processing. Finally, eye-movement patterns, specifically fixation dwell time, continue to be negatively related to math performance after controlling for task performance (i.e. error rate and reaction time) and domain general cognitive abilities (IQ), suggesting that fluent visual processing of Arabic digits plays a unique and important role in linking symbolic number processing to formal math abilities. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermospray Liquid Chromatography/Mass Spectrometry of Mustard and Its Metabolites

DTIC Science & Technology

1989-05-01

MONITORING ORGANIZATION REPORT NUMBER(S) CRDEC-TR-066 6a. NAME OF PERFORMING ORGANIZATION 6b OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION (If applicable...see reverse 6c- ADDRESS (Cty, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code) Ba. NAME OF FUNDING/SPONSORING 8b OFFICE SYMBOL 9...Ather und Thioather in Dioxan- Wasser -Gemischen," Chem, Ber. Vol. 81, p 123 (1948). 2. Capon, B., and McManus, S. P., Neighboring Group Participation

Study of Co-Located and Distant Collaboration with Symbolic Support via a Haptics-Enhanced Virtual Reality Task

ERIC Educational Resources Information Center

Yeh, Shih-Ching; Hwang, Wu-Yuin; Wang, Jin-Liang; Zhan, Shi-Yi

2013-01-01

This study intends to investigate how multi-symbolic representations (text, digits, and colors) could effectively enhance the completion of co-located/distant collaborative work in a virtual reality context. Participants' perceptions and behaviors were also studied. A haptics-enhanced virtual reality task was developed to conduct…

Guidelines for the Acquisition of Aerial Photography for Digital Photo-Interpretation of Submerged Aquatic Vegetation (SAV)

DTIC Science & Technology

2006-10-01

frame ( yellow symbols). Additional control points (red symbols) can be used if initial points do not provide an adequate orthographic solution ERDC TN...56, 245-252. Young, D. R., D. T. Specht , P. J. Clinton, and H. Lee. 1998. Use of color infrared photography to map dis- tributions of eelgrass and

Huffman scanning: using language models within fixed-grid keyboard emulation☆

PubMed Central

Roark, Brian; Beckley, Russell; Gibbons, Chris; Fried-Oken, Melanie

2012-01-01

Individuals with severe motor impairments commonly enter text using a single binary switch and symbol scanning methods. We present a new scanning method –Huffman scanning – which uses Huffman coding to select the symbols to highlight during scanning, thus minimizing the expected bits per symbol. With our method, the user can select the intended symbol even after switch activation errors. We describe two varieties of Huffman scanning – synchronous and asynchronous –and present experimental results, demonstrating speedups over row/column and linear scanning. PMID:24244070

Beneficial effects of reading aloud and solving simple arithmetic calculations (learning therapy) on a wide range of cognitive functions in the healthy elderly: study protocol for a randomized controlled trial

PubMed Central

2012-01-01

Background Almost all cognitive functions decline with age. Results of previous studies have shown that cognitive training related to everyday life (reading aloud and solving simple arithmetic calculations), namely learning therapy, can improve two cognitive function (executive functions and processing speed) in elderly people. However, it remains unclear whether learning therapy engenders improvement of various cognitive functions or not. We investigate the impact of learning therapy on various cognitive functions (executive functions, episodic memory, short-term memory, working memory, attention, reading ability, and processing speed) in healthy older adults. Methods We use a single-blinded intervention with two parallel groups (a learning therapy group and a waiting list control group). Testers are blind to the study hypothesis and the group membership of participants. Through an advertisement in local newspaper, 64 healthy older adults are recruited. They will be assigned randomly to a learning therapy group or a waiting list control group. In the learning therapy group, participants are required to perform two cognitive tasks for 6 months: reading Japanese aloud and solving simple calculations. The waiting list group does not participate in the intervention. The primary outcome measure is the Stroop test score: a measure of executive function. Secondary outcome measures are assessments including the following: verbal fluency task, logical memory, first and second names, digit span forward, digit span backward, Japanese reading test, digit cancellation task, digit symbol coding, and symbol search. We assess these outcome measures before and after the intervention. Discussion This report is the first study which investigates the beneficial effects of learning therapy on a wide range of cognitive functions of elderly people. Our study provides sufficient evidence of learning therapy effectiveness. Most cognitive functions, which are correlated strongly with daily life activities, decrease with age. These study results can elucidate effects of cognitive training on elderly people. Trial registration This trial was registered in The University Hospital Medical Information Network Clinical Trials Registry (No. UMIN000006998). PMID:22483196

Beneficial effects of reading aloud and solving simple arithmetic calculations (learning therapy) on a wide range of cognitive functions in the healthy elderly: study protocol for a randomized controlled trial.

PubMed

Nouchi, Rui; Taki, Yasuyuki; Takeuchi, Hikaru; Hashizume, Hiroshi; Nozawa, Takayuki; Sekiguchi, Atsushi; Nouchi, Haruka; Kawashima, Ryuta

2012-04-06

Almost all cognitive functions decline with age. Results of previous studies have shown that cognitive training related to everyday life (reading aloud and solving simple arithmetic calculations), namely learning therapy, can improve two cognitive function (executive functions and processing speed) in elderly people. However, it remains unclear whether learning therapy engenders improvement of various cognitive functions or not. We investigate the impact of learning therapy on various cognitive functions (executive functions, episodic memory, short-term memory, working memory, attention, reading ability, and processing speed) in healthy older adults. We use a single-blinded intervention with two parallel groups (a learning therapy group and a waiting list control group). Testers are blind to the study hypothesis and the group membership of participants. Through an advertisement in local newspaper, 64 healthy older adults are recruited. They will be assigned randomly to a learning therapy group or a waiting list control group. In the learning therapy group, participants are required to perform two cognitive tasks for 6 months: reading Japanese aloud and solving simple calculations. The waiting list group does not participate in the intervention. The primary outcome measure is the Stroop test score: a measure of executive function. Secondary outcome measures are assessments including the following: verbal fluency task, logical memory, first and second names, digit span forward, digit span backward, Japanese reading test, digit cancellation task, digit symbol coding, and symbol search. We assess these outcome measures before and after the intervention. This report is the first study which investigates the beneficial effects of learning therapy on a wide range of cognitive functions of elderly people. Our study provides sufficient evidence of learning therapy effectiveness. Most cognitive functions, which are correlated strongly with daily life activities, decrease with age. These study results can elucidate effects of cognitive training on elderly people. This trial was registered in The University Hospital Medical Information Network Clinical Trials Registry (No. UMIN000006998).

An Efficient Variable Length Coding Scheme for an IID Source

NASA Technical Reports Server (NTRS)

Cheung, K. -M.

1995-01-01

A scheme is examined for using two alternating Huffman codes to encode a discrete independent and identically distributed source with a dominant symbol. This combined strategy, or alternating runlength Huffman (ARH) coding, was found to be more efficient than ordinary coding in certain circumstances.

Neuropsychological mechanisms of Digit Symbol Substitution Test impairment in Asperger Disorder.

PubMed

Yoran-Hegesh, Roni; Kertzman, Semion; Vishne, Tali; Weizman, Abraham; Kotler, Moshe

2009-03-31

Our aim was to investigate the neurocognitive mechanisms recruited by adolescents with Asperger Disorder (AD), in comparison to controls, and to detect the underlying mechanisms during the complex information processing required for the performance of the Digit Symbol Substitution Test (DSST). Male adolescents (n=23; mean age 15.1+/-3.6 years) with a DSM-IV diagnosis of AD were compared with a normal male control group with similar demographic characteristics (n=43; mean age: 15.1+/-3.6 years). A computerized neurocognitive battery was administered and included: Inspection Time (IT), Finger Tapping Test (FTT), Simple Reaction Time (SRT), Choice Reaction Time (CRT), Digit Running task (DRT), Stroop test and Digit Symbol Substitution Test (DSST). Adolescents with AD performed significantly worse than controls on the DSST. This impaired DSST performance was related to cognitive mechanisms different from those employed by normal controls. Motor slowness and inability to deal with increased amounts of information affected the performance of the AD group, while shifting of attention was the limiting factor in the controls. Both groups were similarly dependent on response selection. This study demonstrated differences in performance in complex cognitive tasks between adolescents with AD and normal controls that may be related to differences in neurocognitive mechanisms underlying information processing. Future neuroimaging studies are needed to clarify the neural network involved in the differences in cognitive performance between AD subjects and normal controls.

Symbolic Numerical Magnitude Processing Is as Important to Arithmetic as Phonological Awareness Is to Reading

PubMed Central

Vanbinst, Kiran; Ansari, Daniel; Ghesquière, Pol; De Smedt, Bert

2016-01-01

In this article, we tested, using a 1-year longitudinal design, whether symbolic numerical magnitude processing or children’s numerical representation of Arabic digits, is as important to arithmetic as phonological awareness is to reading. Children completed measures of symbolic comparison, phonological awareness, arithmetic, reading at the start of third grade and the latter two were retested at the start of fourth grade. Cross-sectional and longitudinal correlations indicated that symbolic comparison was a powerful domain-specific predictor of arithmetic and that phonological awareness was a unique predictor of reading. Crucially, the strength of these independent associations was not significantly different. This indicates that symbolic numerical magnitude processing is as important to arithmetic development as phonological awareness is to reading and suggests that symbolic numerical magnitude processing is a good candidate for screening children at risk for developing mathematical difficulties. PMID:26942935

Updated symbol catalogue for geologic and geomorphologic mapping in Planetary Scinces

NASA Astrophysics Data System (ADS)

Nass, Andrea; Fortezzo, Corey; Skinner, James, Jr.; Hunter, Marc; Hare, Trent

2017-04-01

Maps are one of the most powerful communication tools for spatial data. This is true for terrestrial data, as well as the many types of planetary data. Geologic and/or geomorphologic maps of planetary surfaces, in particular those of the Moon, Mars, and Venus, are standardized products and often prepared as a part of hypothesis-driven science investigations. The NASA-funded Planetary Geologic Mapping program, coordinated by the USGS Astrogeology Science Center (ASC), produces high-quality, standardized, and refereed geologic maps and digital databases of planetary bodies. In this context, 242 geologic, geomorphologic, and thematic map sheets and map series have been published since the 1962. However, outside of this program, numerous non-USGS published maps are created as result of scientific investigations and published, e.g. as figures or supplemental materials within a peer-reviewed journal article. Due to the complexity of planetary surfaces, diversity between different planet surfaces, and the varied resolution of the data, geomorphologic and geologic mapping is a challenging task. Because of these limiting conditions, the mapping process is a highly interpretative work and is mostly limited to remotely sensed satellite data - with a few expetions from rover data. Uniform and an unambiguous data are fundamental to make quality observations that lead to unbiased and supported interpretations, especially when there is no current groundtruthing. To allow for correlation between different map products (digital or analog), the most commonly used spatial objects are predefined cartographic symbols. The Federal Geographic Data Committee (FGDC) Digital Cartographic Standard for Geologic Map Symbolization (DCSGMS) defines the most commonly used symbols, colors, and hatch patterns in one comprehensive document. Chapter 25 of the DCSGMS defines the Planetary Geology Features based on the symbols defined in the Venus Mapper's Handbook. After reviewing the 242 planetary geological maps, we propose to 1) review standardized symbols for planetary maps, and 2) recommend an updated symbol collection for adoption by the planetary mapping community. Within these points, the focus is on the changing of symbology with respect to time and how it effects communication within and between the maps. Two key questions to address are 1) does chapter 25 provides enough variability within the subcategories (e.g., faults) to represent the data within the maps? 2) How recommendations to the mapping community and their steering committees could be delivered to enhance a map's communicability, and convey information succinctly but thoroughly. For determining the most representative symbol collection of existing maps to support future map results (within or outside of USGS mapping program) we defined a stepwise task list: 1) Statistical review of existing symbol sets and collections, 2) Establish a representative symbol set for planetary mapping, 3) Update cartographic symbols, 4) Implementation into GIS-based mapping software (this implementation will mimic the 2010 application of the planetary symbol set into ArcGIS (more information https://planetarymapping.wr.usgs.gov/Project). 6) Platform to provide the symbol set to the mapping community. This project was initiated within an ongoing cooperation work between the USGS ASC and the German Aerospace Center (DLR), Dept. of Planetary Geology.

Probability Quantization for Multiplication-Free Binary Arithmetic Coding

NASA Technical Reports Server (NTRS)

Cheung, K. -M.

1995-01-01

A method has been developed to improve on Witten's binary arithmetic coding procedure of tracking a high value and a low value. The new method approximates the probability of the less probable symbol, which improves the worst-case coding efficiency.

This Rock 'n' Roll Video Teaches Math

ERIC Educational Resources Information Center

Niess, Margaret L.; Walker, Janet M.

2009-01-01

Mathematics is a discipline that has significantly advanced through the use of digital technologies with improved computational, graphical, and symbolic capabilities. Digital videos can be used to present challenging mathematical questions for students. Video clips offer instructional possibilities for moving students from a passive mode of…

A comparison of different methods to implement higher order derivatives of density functionals

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Dam, Hubertus J.J.

Density functional theory is the dominant approach in electronic structure methods today. To calculate properties higher order derivatives of the density functionals are required. These derivatives might be implemented manually,by automatic differentiation, or by symbolic algebra programs. Different authors have cited different reasons for using the particular method of their choice. This paper presents work where all three approaches were used and the strengths and weaknesses of each approach are considered. It is found that all three methods produce code that is suffficiently performanted for practical applications, despite the fact that our symbolic algebra generated code and our automatic differentiationmore » code still have scope for significant optimization. The automatic differentiation approach is the best option for producing readable and maintainable code.« less

Hybrid Analog/Digital Receiver

NASA Technical Reports Server (NTRS)

Brown, D. H.; Hurd, W. J.

1989-01-01

Advanced hybrid analog/digital receiver processes intermediate-frequency (IF) signals carrying digital data in form of phase modulation. Uses IF sampling and digital phase-locked loops to track carrier and subcarrier signals and to synchronize data symbols. Consists of three modules: IF assembly, signal-processing assembly, and test-signal assembly. Intended for use in Deep Space Network, but presumably basic design modified for such terrestrial uses as communications or laboratory instrumentation where signals weak and/or noise strong.

Stochastic Interactive Activation and the Effect of Context on Perception

DTIC Science & Technology

1989-07-14

OFFICE SYMBOL 7a. NAME OP MONITORING ORGANIZATION Caregi-MelonUniersty (if apdlcabile) Computer Sciences DivisionCarngieMelon U vesit j___________ Office...Pittsburgh, Pennsylvania 15213 Arlington, Virginia 22217-5000 Sa. NAME OF FUJNDING /SPONSORING Sb. OFFICE SYMBOL . 9 PROCJREMENT INSTRUMENT IDENTIFICATION...RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Include Area Code) 122c. OFFICE SYMBOL Dr. Alan L. Meyrovitz 1(202) 696-4302 N00014 00 FORM 1473,054 MAR 83 APR

Frame Synchronization Without Attached Sync Markers

NASA Technical Reports Server (NTRS)

Hamkins, Jon

2011-01-01

We describe a method to synchronize codeword frames without making use of attached synchronization markers (ASMs). Instead, the synchronizer identifies the code structure present in the received symbols, by operating the decoder for a handful of iterations at each possible symbol offset and forming an appropriate metric. This method is computationally more complex and doesn't perform as well as frame synchronizers that utilize an ASM; nevertheless, the new synchronizer acquires frame synchronization in about two seconds when using a 600 kbps software decoder, and would take about 15 milliseconds on prototype hardware. It also eliminates the need for the ASMs, which is an attractive feature for short uplink codes whose coding gain would be diminished by the overheard of ASM bits. The lack of ASMs also would simplify clock distribution for the AR4JA low-density parity-check (LDPC) codes and adds a small amount to the coding gain as well (up to 0.2 dB).

INSTRUMENTATION AND CONTROLS DIVISION ELECTRICAL DESIGN STANDARDS AND GRAPHICAL SYMBOLS

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-11-01

Copies are presented of the American Standards Association graphical symbols for electrical and electronic equipment and systems. Recommendations are given for electrical elementary design layout, device codings, etc., for permanent type installations. Electrical diagrams copied from American Drafting Standards Manual are presented. (M.C.G.)

Automatic Testcase Generation for Flight Software

NASA Technical Reports Server (NTRS)

Bushnell, David Henry; Pasareanu, Corina; Mackey, Ryan M.

2008-01-01

The TacSat3 project is applying Integrated Systems Health Management (ISHM) technologies to an Air Force spacecraft for operational evaluation in space. The experiment will demonstrate the effectiveness and cost of ISHM and vehicle systems management (VSM) technologies through onboard operation for extended periods. We present two approaches to automatic testcase generation for ISHM: 1) A blackbox approach that views the system as a blackbox, and uses a grammar-based specification of the system's inputs to automatically generate *all* inputs that satisfy the specifications (up to prespecified limits); these inputs are then used to exercise the system. 2) A whitebox approach that performs analysis and testcase generation directly on a representation of the internal behaviour of the system under test. The enabling technologies for both these approaches are model checking and symbolic execution, as implemented in the Ames' Java PathFinder (JPF) tool suite. Model checking is an automated technique for software verification. Unlike simulation and testing which check only some of the system executions and therefore may miss errors, model checking exhaustively explores all possible executions. Symbolic execution evaluates programs with symbolic rather than concrete values and represents variable values as symbolic expressions. We are applying the blackbox approach to generating input scripts for the Spacecraft Command Language (SCL) from Interface and Control Systems. SCL is an embedded interpreter for controlling spacecraft systems. TacSat3 will be using SCL as the controller for its ISHM systems. We translated the SCL grammar into a program that outputs scripts conforming to the grammars. Running JPF on this program generates all legal input scripts up to a prespecified size. Script generation can also be targeted to specific parts of the grammar of interest to the developers. These scripts are then fed to the SCL Executive. ICS's in-house coverage tools will be run to measure code coverage. Because the scripts exercise all parts of the grammar, we expect them to provide high code coverage. This blackbox approach is suitable for systems for which we do not have access to the source code. We are applying whitebox test generation to the Spacecraft Health INference Engine (SHINE) that is part of the ISHM system. In TacSat3, SHINE will execute an on-board knowledge base for fault detection and diagnosis. SHINE converts its knowledge base into optimized C code which runs onboard TacSat3. SHINE can translate its rules into an intermediate representation (Java) suitable for analysis with JPF. JPF will analyze SHINE's Java output using symbolic execution, producing testcases that can provide either complete or directed coverage of the code. Automatically generated test suites can provide full code coverage and be quickly regenerated when code changes. Because our tools analyze executable code, they fully cover the delivered code, not just models of the code. This approach also provides a way to generate tests that exercise specific sections of code under specific preconditions. This capability gives us more focused testing of specific sections of code.

Democratisation of AAC Symbol Choices Using Technology.

PubMed

Draffan, E A; Wald, Mike; Zeinoun, Nadine; Banes, David

2017-01-01

The use of an online voting system has been developed to enable democratic choices of newly designed symbols to support speech, language and literacy skills in a localisation situation. The system works for those using and supporting Augmentative and Alternative Communication (AAC) symbols on electronic systems by the provision of simplified scales of acceptance and adapted grids. The methodology and results highlighted the importance of user participation at the outset and concrete examples of symbol adaptations that were found necessary to ensure higher levels of user satisfaction. Design changes included appropriate local dress codes, linguistic nuances, social settings, the built environment and religious sensitivities.

Using cellular automata to generate image representation for biological sequences.

PubMed

Xiao, X; Shao, S; Ding, Y; Huang, Z; Chen, X; Chou, K-C

2005-02-01

A novel approach to visualize biological sequences is developed based on cellular automata (Wolfram, S. Nature 1984, 311, 419-424), a set of discrete dynamical systems in which space and time are discrete. By transforming the symbolic sequence codes into the digital codes, and using some optimal space-time evolvement rules of cellular automata, a biological sequence can be represented by a unique image, the so-called cellular automata image. Many important features, which are originally hidden in a long and complicated biological sequence, can be clearly revealed thru its cellular automata image. With biological sequences entering into databanks rapidly increasing in the post-genomic era, it is anticipated that the cellular automata image will become a very useful vehicle for investigation into their key features, identification of their function, as well as revelation of their "fingerprint". It is anticipated that by using the concept of the pseudo amino acid composition (Chou, K.C. Proteins: Structure, Function, and Genetics, 2001, 43, 246-255), the cellular automata image approach can also be used to improve the quality of predicting protein attributes, such as structural class and subcellular location.

SAC (Strategic Air Command) Needs a Few Good Men and Women’ - A Guide to ICBM (Intercontinental Ballistic Missile) Operations Duty

DTIC Science & Technology

1988-04-01

Ditribufion is unlimited. 4 PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) 88-0825 6a NAME OF PERFORMING ORGANIZATION 6b...OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION ACS C/EDC (If applicable) 6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and...ZIP Code) MAXWELL AFB AL 36112-5542 8a. NAME OF FUNDING/SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If

The development of automated access to symbolic and non-symbolic number knowledge in children: an ERP study.

PubMed

Gebuis, Titia; Herfs, Inkeri K; Kenemans, J Leon; de Haan, Edward H F; van der Smagt, Maarten J

2009-11-01

Infants can visually detect changes in numerosity, which suggests that a (non-symbolic) numerosity system is already present early in life. This non-symbolic system is hypothesized to serve as the basis for the later acquired symbolic system. Little is known about the processes underlying the transition from the non-symbolic to symbolic code. In the current study we investigated the development of automatization of symbolic number processing in children from second (6.0 years) and fourth grade (8.0 years) and adults using a symbolic and non-symbolic size congruency task and event-related potentials (ERPs) as a measure. The comparison between symbolic and non-symbolic size congruency effects (SCEs) allowed us to disentangle processes necessary to perform the task from processes specific to numerosity notation. In contrast to previous studies, second graders already revealed a behavioral symbolic SCE similar to that of adults. In addition, the behavioral SCE increased for symbolic and decreased for non-symbolic notation with increasing age. For all age groups, the ERP data showed that the two magnitudes interfered at a level before selective activation of the response system, for both notations. However, only for the second graders distinct processes were recruited to perform the symbolic size comparison task. This shift in recruited processes for the symbolic task only might reflect the functional specialization of the parietal cortex.

Advanced GF(3²) nonbinary LDPC coded modulation with non-uniform 9-QAM outperforming star 8-QAM.

PubMed

Liu, Tao; Lin, Changyu; Djordjevic, Ivan B

2016-06-27

In this paper, we first describe a 9-symbol non-uniform signaling scheme based on Huffman code, in which different symbols are transmitted with different probabilities. By using the Huffman procedure, prefix code is designed to approach the optimal performance. Then, we introduce an algorithm to determine the optimal signal constellation sets for our proposed non-uniform scheme with the criterion of maximizing constellation figure of merit (CFM). The proposed nonuniform polarization multiplexed signaling 9-QAM scheme has the same spectral efficiency as the conventional 8-QAM. Additionally, we propose a specially designed GF(3²) nonbinary quasi-cyclic LDPC code for the coded modulation system based on the 9-QAM non-uniform scheme. Further, we study the efficiency of our proposed non-uniform 9-QAM, combined with nonbinary LDPC coding, and demonstrate by Monte Carlo simulation that the proposed GF(2³) nonbinary LDPC coded 9-QAM scheme outperforms nonbinary LDPC coded uniform 8-QAM by at least 0.8dB.

Reduced circuit implementation of encoder and syndrome generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trager, Barry M; Winograd, Shmuel

An error correction method and system includes an Encoder and Syndrome-generator that operate in parallel to reduce the amount of circuitry used to compute check symbols and syndromes for error correcting codes. The system and method computes the contributions to the syndromes and check symbols 1 bit at a time instead of 1 symbol at a time. As a result, the even syndromes can be computed as powers of the odd syndromes. Further, the system assigns symbol addresses so that there are, for an example GF(2.sup.8) which has 72 symbols, three (3) blocks of addresses which differ by a cubemore » root of unity to allow the data symbols to be combined for reducing size and complexity of odd syndrome circuits. Further, the implementation circuit for generating check symbols is derived from syndrome circuit using the inverse of the part of the syndrome matrix for check locations.« less

39 CFR Appendix A to Part 121 - Tables Depicting Service Standard Day Ranges

Code of Federal Regulations, 2014 CFR

2014-07-01

... (Days) Alaska Hawaii, Guam, & American Samoa Puerto Rico & USVI Periodicals 1 1-3 1 1-3 1-4 (AK)11 (JNU... 2-3 12 11 11 AK = Alaska 3-digit ZIP Codes 995-997; JNU = Juneau AK 3-digit ZIP Code 998; KTN = Ketchikan AK 3-digit ZIP Code 999; HI = Hawaii 3-digit ZIP Codes 967 and 968; GU = Guam 3-digit ZIP Code 969...

Putting Priors in Mixture Density Mercer Kernels

NASA Technical Reports Server (NTRS)

Srivastava, Ashok N.; Schumann, Johann; Fischer, Bernd

2004-01-01

This paper presents a new methodology for automatic knowledge driven data mining based on the theory of Mercer Kernels, which are highly nonlinear symmetric positive definite mappings from the original image space to a very high, possibly infinite dimensional feature space. We describe a new method called Mixture Density Mercer Kernels to learn kernel function directly from data, rather than using predefined kernels. These data adaptive kernels can en- code prior knowledge in the kernel using a Bayesian formulation, thus allowing for physical information to be encoded in the model. We compare the results with existing algorithms on data from the Sloan Digital Sky Survey (SDSS). The code for these experiments has been generated with the AUTOBAYES tool, which automatically generates efficient and documented C/C++ code from abstract statistical model specifications. The core of the system is a schema library which contains template for learning and knowledge discovery algorithms like different versions of EM, or numeric optimization methods like conjugate gradient methods. The template instantiation is supported by symbolic- algebraic computations, which allows AUTOBAYES to find closed-form solutions and, where possible, to integrate them into the code. The results show that the Mixture Density Mercer-Kernel described here outperforms tree-based classification in distinguishing high-redshift galaxies from low- redshift galaxies by approximately 16% on test data, bagged trees by approximately 7%, and bagged trees built on a much larger sample of data by approximately 2%.

Terabit bandwidth-adaptive transmission using low-complexity format-transparent digital signal processing.

PubMed

Zhuge, Qunbi; Morsy-Osman, Mohamed; Chagnon, Mathieu; Xu, Xian; Qiu, Meng; Plant, David V

2014-02-10

In this paper, we propose a low-complexity format-transparent digital signal processing (DSP) scheme for next generation flexible and energy-efficient transceiver. It employs QPSK symbols as the training and pilot symbols for the initialization and tracking stage of the receiver-side DSP, respectively, for various modulation formats. The performance is numerically and experimentally evaluated in a dual polarization (DP) 11 Gbaud 64QAM system. Employing the proposed DSP scheme, we conduct a system-level study of Tb/s bandwidth-adaptive superchannel transmissions with flexible modulation formats including QPSK, 8QAM and 16QAM. The spectrum bandwidth allocation is realized in the digital domain instead of turning on/off sub-channels, which improves the performance of higher order QAM. Various transmission distances ranging from 240 km to 6240 km are demonstrated with a colorless detection for hardware complexity reduction.

Navigating Mythic Space in the Digital Age

ERIC Educational Resources Information Center

Foley, Drew Thomas

2012-01-01

In prior ages, alternate worlds are associated with symbolic expressions of storied space, here termed "mythic space." The digital age brings new forms of virtual space that are co-existent with physical space. These virtual spaces may be understood as a contemporary representation of mythic space. This dissertation explores the paths by…

Effects of interactive metronome therapy on cognitive functioning after blast-related brain injury: a randomized controlled pilot trial.

PubMed

Nelson, Lonnie A; Macdonald, Margaret; Stall, Christina; Pazdan, Renee

2013-11-01

We report preliminary findings on the efficacy of interactive metronome (IM) therapy for the remediation of cognitive difficulties in soldiers with persisting cognitive complaints following blast-related mild-to-moderate traumatic brain injury (TBI). Forty-six of a planned sample of 50 active duty soldiers with persistent cognitive complaints following a documented history of blast-related TBI of mild-to-moderate severity were randomly assigned to receive either standard rehabilitation care (SRC) or SRC plus a 15-session standardized course of IM therapy. Primary outcome measures were Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Index Scores. Secondary outcome measures included selected subtests from the Delis-Kaplan Executive Functioning System (Trail Making Test and Color-Word Interference) and the Wechsler Adult Intelligence Scale-Fourth Edition (Symbol Search, Digit-Symbol Coding, Digit Span, and Letter-Number Sequencing) as well as the Integrated Visual and Auditory Continuous Performance Test. Significant group differences (SRC vs. IM) were observed for RBANS Attention (p = .044), Immediate Memory (p = .019), and Delayed Memory (p = .031) indices in unadjusted analyses, with the IM group showing significantly greater improvement at Time 2 than the SRC group, with effect sizes in the medium-to-large range in the adjusted analyses for each outcome (Cohen's d = 0.511, 0.768, and 0.527, respectively). Though not all were statistically significant, effects in 21 of 26 cognitive outcome measures were consistently in favor of the IM treatment group (binomial probability = .00098). The addition of IM therapy to SRC appears to have a positive effect on neuropsychological outcomes for soldiers who have sustained mild-to-moderate TBI and have persistent cognitive complaints after the period for expected recovery has passed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Orbital Maneuvering Engine Feed System Coupled Stability Investigation, Computer User's Manual

NASA Technical Reports Server (NTRS)

Schuman, M. D.; Fertig, K. W.; Hunting, J. K.; Kahn, D. R.

1975-01-01

An operating manual for the feed system coupled stability model was given, in partial fulfillment of a program designed to develop, verify, and document a digital computer model that can be used to analyze and predict engine/feed system coupled instabilities in pressure-fed storable propellant propulsion systems over a frequency range of 10 to 1,000 Hz. The first section describes the analytical approach to modelling the feed system hydrodynamics, combustion dynamics, chamber dynamics, and overall engineering model structure, and presents the governing equations in each of the technical areas. This is followed by the program user's guide, which is a complete description of the structure and operation of the computerized model. Last, appendices provide an alphabetized FORTRAN symbol table, detailed program logic diagrams, computer code listings, and sample case input and output data listings.

A comparison of Manchester symbol tracking loops for block 5 applications

NASA Technical Reports Server (NTRS)

Holmes, J. K.

1991-01-01

The linearized tracking errors of three Manchester (biphase coded) symbol tracking loops are compared to determine which is appropriate for Block 5 receiver applications. The first is a nonreturn to zero (NRZ) symbol synchronizer loop operating at twice the symbol rate (NRZ x 2) so that it operates on half symbols. The second near optimally processes the mid-symbol transitions and ignores the between symbol transitions. In the third configuration, the first two approaches are combined as a hybrid to produce the best performance. Although this hybrid loop is the best at low symbol signal to noise ratios (SNRs), it has about the same performance as the NRZ x 2 loop at higher SNRs (greater than 0-dB E sub s/N sub 0). Based on this analysis, it is tentatively recommended that the hybrid loop be implemented for Manchester data in the Block 5 receiver. However, the high data rate case and the hardware implications of each implementation must be understood and analyzed before the hybrid loop is recommended unconditionally.

Achievable Information Rates for Coded Modulation With Hard Decision Decoding for Coherent Fiber-Optic Systems

NASA Astrophysics Data System (ADS)

Sheikh, Alireza; Amat, Alexandre Graell i.; Liva, Gianluigi

2017-12-01

We analyze the achievable information rates (AIRs) for coded modulation schemes with QAM constellations with both bit-wise and symbol-wise decoders, corresponding to the case where a binary code is used in combination with a higher-order modulation using the bit-interleaved coded modulation (BICM) paradigm and to the case where a nonbinary code over a field matched to the constellation size is used, respectively. In particular, we consider hard decision decoding, which is the preferable option for fiber-optic communication systems where decoding complexity is a concern. Recently, Liga \\emph{et al.} analyzed the AIRs for bit-wise and symbol-wise decoders considering what the authors called \\emph{hard decision decoder} which, however, exploits \\emph{soft information} of the transition probabilities of discrete-input discrete-output channel resulting from the hard detection. As such, the complexity of the decoder is essentially the same as the complexity of a soft decision decoder. In this paper, we analyze instead the AIRs for the standard hard decision decoder, commonly used in practice, where the decoding is based on the Hamming distance metric. We show that if standard hard decision decoding is used, bit-wise decoders yield significantly higher AIRs than symbol-wise decoders. As a result, contrary to the conclusion by Liga \\emph{et al.}, binary decoders together with the BICM paradigm are preferable for spectrally-efficient fiber-optic systems. We also design binary and nonbinary staircase codes and show that, in agreement with the AIRs, binary codes yield better performance.

The Mediating Relation between Symbolic and Nonsymbolic Foundations of Math Competence

PubMed Central

Price, Gavin R.; Fuchs, Lynn S.

2016-01-01

This study investigated the relation between symbolic and nonsymbolic magnitude processing abilities with 2 standardized measures of math competence (WRAT Arithmetic and KeyMath Numeration) in 150 3rd- grade children (mean age 9.01 years). Participants compared sets of dots and pairs of Arabic digits with numerosities 1–9 for relative numerical magnitude. In line with previous studies, performance on both symbolic and nonsymbolic magnitude processing was related to math ability. Performance metrics combining reaction and accuracy, as well as weber fractions, were entered into mediation models with standardized math test scores. Results showed that symbolic magnitude processing ability fully mediates the relation between nonsymbolic magnitude processing and math ability, regardless of the performance metric or standardized test. PMID:26859564

The Mediating Relation between Symbolic and Nonsymbolic Foundations of Math Competence.

PubMed

Price, Gavin R; Fuchs, Lynn S

2016-01-01

This study investigated the relation between symbolic and nonsymbolic magnitude processing abilities with 2 standardized measures of math competence (WRAT Arithmetic and KeyMath Numeration) in 150 3rd-grade children (mean age 9.01 years). Participants compared sets of dots and pairs of Arabic digits with numerosities 1-9 for relative numerical magnitude. In line with previous studies, performance on both symbolic and nonsymbolic magnitude processing was related to math ability. Performance metrics combining reaction and accuracy, as well as weber fractions, were entered into mediation models with standardized math test scores. Results showed that symbolic magnitude processing ability fully mediates the relation between nonsymbolic magnitude processing and math ability, regardless of the performance metric or standardized test.

Data compression and information retrieval via symbolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, X.Z.; Tracy, E.R.

Converting a continuous signal into a multisymbol stream is a simple method of data compression which preserves much of the dynamical information present in the original signal. The retrieval of selected types of information from symbolic data involves binary operations and is therefore optimal for digital computers. For example, correlation time scales can be easily recovered, even at high noise levels, by varying the time delay for symbolization. Also, the presence of periodicity in the signal can be reliably detected even if it is weak and masked by a dominant chaotic/stochastic background. {copyright} {ital 1998 American Institute of Physics.}

Performance on the Wechsler Adult Intelligence Scale-III in Japanese patients with schizophrenia.

PubMed

Fujino, Haruo; Sumiyoshi, Chika; Sumiyoshi, Tomiki; Yasuda, Yuka; Yamamori, Hidenaga; Ohi, Kazutaka; Fujimoto, Michiko; Umeda-Yano, Satomi; Higuchi, Arisa; Hibi, Yumiko; Matsuura, Yukako; Hashimoto, Ryota; Takeda, Masatoshi; Imura, Osamu

2014-07-01

Patients with schizophrenia have been reported to perform worse than non-schizophrenic populations on neuropsychological tests, which may be affected by cultural factors. The aim of this study was to examine the performance of a sizable number of patients with schizophrenia on the Japanese version of the Wechsler Adult Intelligence Scale-III (WAIS-III) compared with healthy controls. Performance on the WAIS-III was evaluated in 157 Japanese patients with schizophrenia and in 264 healthy control subjects. All IQ scores and four indices from the WAIS-III were impaired for patients with schizophrenia compared with healthy controls. Processing Speed was markedly disturbed, approximately 2 SD below that of the healthy control group. Among the 13 subtests, Comprehension (z = -1.70, d = 1.55), Digit Symbol Coding (z = -1.84, d = 1.88), and Symbol Search (z = -1.85, d = 1.77) were profoundly impaired relative to the healthy controls. These results indicate that the pattern and degree of impairment, as evaluated by the WAIS-III, in Japanese patients are similar to those previously reported in English-speaking patients and that the deficits of some neuropsychological domains relevant to functional outcomes are universally characteristic of schizophrenia. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

Kramers-Kronig receiver operable without digital upsampling.

PubMed

Bo, Tianwai; Kim, Hoon

2018-05-28

The Kramers-Kronig (KK) receiver is capable of retrieving the phase information of optical single-sideband (SSB) signal from the optical intensity when the optical signal satisfies the minimum phase condition. Thus, it is possible to direct-detect the optical SSB signal without suffering from the signal-signal beat interference and linear transmission impairments. However, due to the spectral broadening induced by nonlinear operations in the conventional KK algorithm, it is necessary to employ the digital upsampling at the beginning of the digital signal processing (DSP). The increased number of samples at the DSP would hinder the real-time implementation of this attractive receiver. Hence, we propose a new DSP algorithm for KK receiver operable at 2 samples per symbol. We adopt a couple of mathematical approximations to avoid the use of nonlinear operations such as logarithm and exponential functions. By using the proposed algorithm, we demonstrate the transmission of 112-Gb/s SSB orthogonal frequency-division-multiplexed signal over an 80-km fiber link. The results show that the proposed algorithm operating at 2 samples per symbol exhibits similar performance to the conventional KK one operating at 6 samples per symbol. We also present the error analysis of the proposed algorithm for KK receiver in comparison with the conventional one.

A Comparative Study : Microprogrammed Vs Risc Architectures For Symbolic Processing

NASA Astrophysics Data System (ADS)

Heudin, J. C.; Metivier, C.; Demigny, D.; Maurin, T.; Zavidovique, B.; Devos, F.

1987-05-01

It is oftenclaimed that conventional computers are not well suited for human-like tasks : Vision (Image Processing), Intelligence (Symbolic Processing) ... In the particular case of Artificial Intelligence, dynamic type-checking is one example of basic task that must be improved. The solution implemented in most Lisp work-stations consists in a microprogrammed architecture with a tagged memory. Another way to gain efficiency is to design a well suited instruction set for symbolic processing, which reduces the semantic gap between the high level language and the machine code. In this framework, the RISC concept provides a convenient approach to study new architectures for symbolic processing. This paper compares both approaches and describes our projectof designing a compact symbolic processor for Artificial Intelligence applications.

[A Symbol of Connectedness Between the Self and the Tribal Home: Betel Quid in the Lives of Indigenous Taiwanese].

PubMed

Ma, Wei-Fen; Li, Chia-Ing; Gritz, Ellen R; Tamí-Maury, Irene; Lam, Cho; Lin, Cheng-Chieh

2017-06-01

Betel quid chewing plays a significant role in the development of oral cancer, yet the high prevalence of betel quid use remains a serious health problem in Taiwan, especially among indigenous Taiwanese. The present study aimed to understand the reasons behind betel-quid chewing among indigenous Taiwanese people by examining the larger context of their culture and traditions. This descriptive, qualitative study recruited ten regular betel quid indigenous chewers using purposive and snowball sampling. Four of the participants were interviewed individually and the remaining six comprised a focus group. Data were collected using in-depth interviews with semi-structured guidelines and analyzed using qualitative content analysis following the process of open coding, identifying codes, giving meaningful names to codes, putting similar codes in categories, and grouping categories into themes. Most of the participants associated betel quid with significant aspects of life, with betel quid symbolizing social belonging. In indigenous cultures, betel nut embodies the enduring companionship of lifelong friends. For the study participants, chewing betel quid was associated with symbolic meanings associated with the following five themes: betel quid chewing helps reinforce self-identity and sense of belonging; betel quid is considered a traditional symbol of love and marriage; betel quid reflects the celebration of simple abundance in indigenous life; betel quid represents an attitude toward life that accentuates the importance of learning to live in everlasting harmony with the environment and nature; and betel quid chewing is used to cure physical ailments and mitigate dental problems. Beliefs related to chewing betel quid deeply impact the attitudes of indigenous people toward this behavior. Because chewing betel quid is an essential part of Taiwanese indigenous community life, the cultural and symbolic meanings of this practice must be taken into consideration when drafting related policies and developing cessation programs in order to help indigenous betel-quid chewers effectively reduce the risk of developing oral cancers.

An Ensemble Approach to Building Mercer Kernels with Prior Information

NASA Technical Reports Server (NTRS)

Srivastava, Ashok N.; Schumann, Johann; Fischer, Bernd

2005-01-01

This paper presents a new methodology for automatic knowledge driven data mining based on the theory of Mercer Kernels, which are highly nonlinear symmetric positive definite mappings from the original image space to a very high, possibly dimensional feature space. we describe a new method called Mixture Density Mercer Kernels to learn kernel function directly from data, rather than using pre-defined kernels. These data adaptive kernels can encode prior knowledge in the kernel using a Bayesian formulation, thus allowing for physical information to be encoded in the model. Specifically, we demonstrate the use of the algorithm in situations with extremely small samples of data. We compare the results with existing algorithms on data from the Sloan Digital Sky Survey (SDSS) and demonstrate the method's superior performance against standard methods. The code for these experiments has been generated with the AUTOBAYES tool, which automatically generates efficient and documented C/C++ code from abstract statistical model specifications. The core of the system is a schema library which contains templates for learning and knowledge discovery algorithms like different versions of EM, or numeric optimization methods like conjugate gradient methods. The template instantiation is supported by symbolic-algebraic computations, which allows AUTOBAYES to find closed-form solutions and, where possible, to integrate them into the code.

Symbolic comparisons of objects on color attributes.

PubMed

Paivio, A; te Linde, J

1980-11-01

Symbolic comparisons of object brightness and color were investigated in two experiments using words and outline drawings as stimuli. Both experiments yielded orderly symbolic distance effects. Contrary to prediction, no reliable picture advantages emerged. For color comparison, individual differences in word fluency and color memory predicted decision time with word stimuli. These results contrast sharply with those of previous comparison studies involving concrete dimensions. The results are discussed in terms of dual-coding theory and the role of verbal mechanisms in memory for object color.

Validity of Empirical Studies of Information System Effectiveness

DTIC Science & Technology

1989-06-01

34The Methodologies of Symbolic Interactionism : A Critical Review of Research Techniques," (Perprint), 1968. Durand, Douglas E., Rex 0. Bennet and Samuel...is unlimited 4 PERFORMING ORGANIZATION REPORT NuMBER(S) 5 MONITORING ORGANZAT,O% REPORT NurM8C’ZS, 6a NAME OF PERFORMING ORGANIZATION 6b OFiCE SYMBOL ...7b ADDRESS (City. State and ZIP Code) Monterey, California 93943-5000 Monterey, California 93943-5000 8a NAME Of rJ.DfNG SPONSOR NrT 8b OFF CE SYMBOL

Single Crystal Fibers of MGO:LiNbO3

DTIC Science & Technology

1990-08-07

MONITORING ORGANIZATION REPORT NUMBER(S) F49620-88-C-0084 V AFOSR.TR.N/AI ’ 1 189 6a. NAME OF PERFORMING ORGANIZATION 16bAFICE SYMBOL 7a. NAME OF...FUNDING/ SPONSORING 8b. OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION S(If applible) USAF, AFSC I _____ Contract # F49620...DTIC USERS (U) 2Za NAME OF RESPONSIBLE INnIVIIL . 22b TELEPHONE (Include Area Code) 22c. OFFICE SYMBOL I) I /) F hr0 Form 1473, JUN 86 Prev4u seditions

An Autonomous Circuit for the Measurement of Photovoltaic Devices Parameters.

DTIC Science & Technology

1986-09-01

Comparison Data, Gallium Arsenide ................ 80 A 7 A,. TABLE OF SYMBOLS A Curve Fitting Constant ADC Analog to Digital Converter AMO Air-Mass-Zero...in Radiation Fluence in the Logarithmic Region CMOS Complementary Metal-Oxide Semiconductor DAC Digital to Analog Converter DC Direct Current Dp Hole...characteristics of individual solar cells. A novel circuit is developed that uses a microprocessor controlled Digital to Analog Converter (DAC) to obtain

47 CFR 15.214 - Cordless telephones.

Code of Federal Regulations, 2010 CFR

2010-10-01

... discrete digital codes. Factory-set codes must be continuously varied over at least 256 possible codes as... readily select from among at least 256 possible discrete digital codes. The cordless telephone shall be... fixed code that is continuously varied among at least 256 discrete digital codes as each telephone is...

40 CFR 1051.805 - What symbols, acronyms, and abbreviations does this part use?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Definitions and Other Reference Information § 1051.805 What symbols, acronyms, and abbreviations does this...—American Society for Testing and Materials. ATV—all-terrain vehicle. cc—cubic centimeters. CFR—Code of...—pounds per square inches of gauge pressure. rpm—revolutions per minute. SAE—Society of Automotive...

Maximum Likelihood Detection of Low Rate Repeat Codes in Frequency Hopped Systems

DTIC Science & Technology

2013-04-01

Communications, vol. 33, pp. 385 – 393, May 1985. [4] W. Sweldens, “Fast block noncoherent decoding,” IEEE Commun. Lett., vol. 5, pp. 132–134, Apr...2001. [5] I. Motedayen-Aval and A. Anastasopoulos, “Polynomial- complexity noncoherent symbol-by-symbol detection with application to adaptive

Numerical magnitude processing in children with mild intellectual disabilities.

PubMed

Brankaer, Carmen; Ghesquière, Pol; De Smedt, Bert

2011-01-01

The present study investigated numerical magnitude processing in children with mild intellectual disabilities (MID) and examined whether these children have difficulties in the ability to represent numerical magnitudes and/or difficulties in the ability to access numerical magnitudes from formal symbols. We compared the performance of 26 children with MID on a symbolic (digits) and a non-symbolic (dot-arrays) comparison task with the performance of two control groups of typically developing children: one group matched on chronological age and one group matched on mathematical ability level. Findings revealed that children with MID performed more poorly than their typically developing chronological age-matched peers on both the symbolic and non-symbolic comparison tasks, while their performance did not substantially differ from the ability-matched control group. These findings suggest that the development of numerical magnitude representation in children with MID is marked by a delay. This performance pattern was observed for both symbolic and non-symbolic comparison tasks, although difficulties on the former task were more prominent. Interventions in children with MID should therefore foster both the development of magnitude representations and the connections between symbols and the magnitudes they represent. Copyright © 2011 Elsevier Ltd. All rights reserved.

39 CFR Appendix A to Part 121 - Tables Depicting Service Standard Day Ranges

Code of Federal Regulations, 2011 CFR

2011-07-01

... 1-3 (AK)7 (JNU) 7 (KTN) 1 (HI)7 (GU) 1-2 1-2 6-7 5-6 Standard Mail 2 3 3 3-4 10 10 9 Package Services 1 2 2 2-3 8 8 7 AK = Alaska 3-digit ZIP Codes 995-997; JNU = Juneau AK 3-digit ZIP Code 998; KTN = Ketchikan AK 3-digit ZIP Code 999; HI = Hawaii 3-digit ZIP Codes 967 and 968; GU = Guam 3-digit ZIP Code 969...

39 CFR Appendix A to Part 121 - Tables Depicting Service Standard Day Ranges

Code of Federal Regulations, 2010 CFR

2010-07-01

... 1-3 (AK)7 (JNU) 7 (KTN) 1 (HI)7 (GU) 1-2 1-2 6-7 5-6 Standard Mail 2 3 3 3-4 10 10 9 Package Services 1 2 2 2-3 8 8 7 AK = Alaska 3-digit ZIP Codes 995-997; JNU = Juneau AK 3-digit ZIP Code 998; KTN = Ketchikan AK 3-digit ZIP Code 999; HI = Hawaii 3-digit ZIP Codes 967 and 968; GU = Guam 3-digit ZIP Code 969...

Experimental demonstration of iterative post-equalization algorithm for 37.5-Gbaud PM-16QAM quad-carrier Terabit superchannel.

PubMed

Jia, Zhensheng; Chien, Hung-Chang; Cai, Yi; Yu, Jianjun; Zhang, Chengliang; Li, Junjie; Ma, Yiran; Shang, Dongdong; Zhang, Qi; Shi, Sheping; Wang, Huitao

2015-02-09

We experimentally demonstrate a quad-carrier 1-Tb/s solution with 37.5-GBaud PM-16QAM signal over 37.5-GHz optical grid at 6.7 b/s/Hz net spectral efficiency. Digital Nyquist pulse shaping at the transmitter and post-equalization at the receiver are employed to mitigate the impairments of joint inter-symbol-interference (ISI) and inter-channel-interference (ICI) symbol degradation. The post-equalization algorithms consist of one sample/symbol based decision-directed least mean square (DD-LMS) adaptive filter, digital post filter and maximum likelihood sequence estimation (MLSE), and a positive iterative process among them. By combining these algorithms, the improvement as much as 4-dB OSNR (0.1nm) at SD-FEC limit (Q(2) = 6.25 corresponding to BER = 2.0e-2) is obtained when compared to no such post-equalization process, and transmission over 820-km EDFA-only standard single-mode fiber (SSMF) link is achieved for two 1.2-Tb/s signals with the averaged Q(2) factor larger than 6.5 dB for all sub-channels. Additionally, 50-GBaud 16QAM operating at 1.28 samples/symbol in a DAC is also investigated and successful transmission over 410-km SSMF link is achieved at 62.5-GHz optical grid.

Symbolic manipulation techniques for vibration analysis of laminated elliptic plates

NASA Technical Reports Server (NTRS)

Andersen, C. M.; Noor, A. K.

1977-01-01

A computational scheme is presented for the free vibration analysis of laminated composite elliptic plates. The scheme is based on Hamilton's principle, the Rayleigh-Ritz technique and symmetry considerations and is implemented with the aid of the MACSYMA symbolic manipulation system. The MACYSMA system, through differentiation, integration, and simplification of analytic expressions, produces highly-efficient FORTRAN code for the evaluation of the stiffness and mass coefficients. Multiple use is made of this code to obtain not only the frequencies and mode shapes of the plate, but also the derivatives of the frequencies with respect to various material and geometric parameters.

Explicit robust schemes for implementation of a class of principal value-based constitutive models: Symbolic and numeric implementation

NASA Technical Reports Server (NTRS)

Arnold, S. M.; Saleeb, A. F.; Tan, H. Q.; Zhang, Y.

1993-01-01

The issue of developing effective and robust schemes to implement a class of the Ogden-type hyperelastic constitutive models is addressed. To this end, special purpose functions (running under MACSYMA) are developed for the symbolic derivation, evaluation, and automatic FORTRAN code generation of explicit expressions for the corresponding stress function and material tangent stiffness tensors. These explicit forms are valid over the entire deformation range, since the singularities resulting from repeated principal-stretch values have been theoretically removed. The required computational algorithms are outlined, and the resulting FORTRAN computer code is presented.

Performance of concatenated Reed-Solomon/Viterbi channel coding

NASA Technical Reports Server (NTRS)

Divsalar, D.; Yuen, J. H.

1982-01-01

The concatenated Reed-Solomon (RS)/Viterbi coding system is reviewed. The performance of the system is analyzed and results are derived with a new simple approach. A functional model for the input RS symbol error probability is presented. Based on this new functional model, we compute the performance of a concatenated system in terms of RS word error probability, output RS symbol error probability, bit error probability due to decoding failure, and bit error probability due to decoding error. Finally we analyze the effects of the noisy carrier reference and the slow fading on the system performance.

Throughput Optimization Via Adaptive MIMO Communications

DTIC Science & Technology

2006-05-30

End-to-end matlab packet simulation platform. * Low density parity check code (LDPCC). * Field trials with Silvus DSP MIMO testbed. * High mobility...incorporate advanced LDPC (low density parity check) codes . Realizing that the power of LDPC codes come at the price of decoder complexity, we also...Channel Coding Binary Convolution Code or LDPC Packet Length 0 - 216-1, bytes Coding Rate 1/2, 2/3, 3/4, 5/6 MIMO Channel Training Length 0 - 4, symbols

Convolutional coding results for the MVM '73 X-band telemetry experiment

NASA Technical Reports Server (NTRS)

Layland, J. W.

1978-01-01

Results of simulation of several short-constraint-length convolutional codes using a noisy symbol stream obtained via the turnaround ranging channels of the MVM'73 spacecraft are presented. First operational use of this coding technique is on the Voyager mission. The relative performance of these codes in this environment is as previously predicted from computer-based simulations.

Flexible Automatic Discretization for Finite Differences: Eliminating the Human Factor

NASA Astrophysics Data System (ADS)

Pranger, Casper

2017-04-01

In the geophysical numerical modelling community, finite differences are (in part due to their small footprint) a popular spatial discretization method for PDEs in the regular-shaped continuum that is the earth. However, they rapidly become prone to programming mistakes when physics increase in complexity. To eliminate opportunities for human error, we have designed an automatic discretization algorithm using Wolfram Mathematica, in which the user supplies symbolic PDEs, the number of spatial dimensions, and a choice of symbolic boundary conditions, and the script transforms this information into matrix- and right-hand-side rules ready for use in a C++ code that will accept them. The symbolic PDEs are further used to automatically develop and perform manufactured solution benchmarks, ensuring at all stages physical fidelity while providing pragmatic targets for numerical accuracy. We find that this procedure greatly accelerates code development and provides a great deal of flexibility in ones choice of physics.

High data rate Reed-Solomon encoding and decoding using VLSI technology

NASA Technical Reports Server (NTRS)

Miller, Warner; Morakis, James

1987-01-01

Presented as an implementation of a Reed-Solomon encode and decoder, which is 16-symbol error correcting, each symbol is 8 bits. This Reed-Solomon (RS) code is an efficient error correcting code that the National Aeronautics and Space Administration (NASA) will use in future space communications missions. A Very Large Scale Integration (VLSI) implementation of the encoder and decoder accepts data rates up 80 Mbps. A total of seven chips are needed for the decoder (four of the seven decoding chips are customized using 3-micron Complementary Metal Oxide Semiconduction (CMOS) technology) and one chip is required for the encoder. The decoder operates with the symbol clock being the system clock for the chip set. Approximately 1.65 billion Galois Field (GF) operations per second are achieved with the decoder chip set and 640 MOPS are achieved with the encoder chip.

(Non-)symbolic magnitude processing in children with mathematical difficulties: A meta-analysis.

PubMed

Schwenk, Christin; Sasanguie, Delphine; Kuhn, Jörg-Tobias; Kempe, Sophia; Doebler, Philipp; Holling, Heinz

2017-05-01

Symbolic and non-symbolic magnitude representations, measured by digit or dot comparison tasks, are assumed to underlie the development of arithmetic skills. The comparison distance effect (CDE) has been suggested as a hallmark of the preciseness of mental magnitude representations. It implies that two magnitudes are harder to discriminate when the numerical distance between them is small, and may therefore differ in children with mathematical difficulties (MD), i.e. low mathematical achievement or dyscalculia. However, empirical findings on the CDE in children with MD are heterogeneous, and only few studies assess both symbolic and non-symbolic skills. This meta-analysis therefore integrates 44 symbolic and 48 non-symbolic response time (RT) outcomes reported in nineteen studies (N=1630 subjects, aged 6-14 years). Independent of age, children with MD show significantly longer mean RTs than typically achieving controls, particularly on symbolic (Hedges' g=0.75; 95% CI [0.51; 0.99]), but to a significantly lower extent also on non-symbolic (g=0.24; 95% CI [0.13; 0.36]) tasks. However, no group differences were found for the CDE. Extending recent work, these meta-analytical findings on children with MD corroborate the diagnostic importance of magnitude comparison speed in symbolic tasks. By contrast, the validity of CDE measures in assessing MD is questioned. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Survey of New Trends in Symbolic Execution for Software Testing and Analysis

NASA Technical Reports Server (NTRS)

Pasareanu, Corina S.; Visser, Willem

2009-01-01

Symbolic execution is a well-known program analysis technique which represents values of program inputs with symbolic values instead of concrete (initialized) data and executes the program by manipulating program expressions involving the symbolic values. Symbolic execution has been proposed over three decades ago but recently it has found renewed interest in the research community, due in part to the progress in decision procedures, availability of powerful computers and new algorithmic developments. We provide a survey of some of the new research trends in symbolic execution, with particular emphasis on applications to test generation and program analysis. We first describe an approach that handles complex programming constructs such as input data structures, arrays, as well as multi-threading. We follow with a discussion of abstraction techniques that can be used to limit the (possibly infinite) number of symbolic configurations that need to be analyzed for the symbolic execution of looping programs. Furthermore, we describe recent hybrid techniques that combine concrete and symbolic execution to overcome some of the inherent limitations of symbolic execution, such as handling native code or availability of decision procedures for the application domain. Finally, we give a short survey of interesting new applications, such as predictive testing, invariant inference, program repair, analysis of parallel numerical programs and differential symbolic execution.

A hybrid symbolic/finite-element algorithm for solving nonlinear optimal control problems

NASA Technical Reports Server (NTRS)

Bless, Robert R.; Hodges, Dewey H.

1991-01-01

The general code described is capable of solving difficult nonlinear optimal control problems by using finite elements and a symbolic manipulator. Quick and accurate solutions are obtained with a minimum for user interaction. Since no user programming is required for most problems, there are tremendous savings to be gained in terms of time and money.

The Changing Nature of Organizational Leadership and Culture in Academic Work

ERIC Educational Resources Information Center

Tierney, William G.

2006-01-01

The author argues that leadership is a cultural construct embedded in symbolic processes. By culture, the author refers to the informal codes and shared assumptions of individuals who participate in an organization. An organization's members shape and are shaped by the symbols and rituals of the institution as well as the unique history from which…

Communications and Information: Compendium of Communications and Information Terminology

DTIC Science & Technology

2002-02-01

Basic Access Module BASIC— Beginners All-Purpose Symbolic Instruction Code BBP—Baseband Processor BBS—Bulletin Board Service (System) BBTC—Broadband...media, formats and labels, programming language, computer documentation, flowcharts and terminology, character codes, data communications and input

Automatic code generation in SPARK: Applications of computer algebra and compiler-compilers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nataf, J.M.; Winkelmann, F.

We show how computer algebra and compiler-compilers are used for automatic code generation in the Simulation Problem Analysis and Research Kernel (SPARK), an object oriented environment for modeling complex physical systems that can be described by differential-algebraic equations. After a brief overview of SPARK, we describe the use of computer algebra in SPARK's symbolic interface, which generates solution code for equations that are entered in symbolic form. We also describe how the Lex/Yacc compiler-compiler is used to achieve important extensions to the SPARK simulation language, including parametrized macro objects and steady-state resetting of a dynamic simulation. The application of thesemore » methods to solving the partial differential equations for two-dimensional heat flow is illustrated.« less

Automatic code generation in SPARK: Applications of computer algebra and compiler-compilers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nataf, J.M.; Winkelmann, F.

We show how computer algebra and compiler-compilers are used for automatic code generation in the Simulation Problem Analysis and Research Kernel (SPARK), an object oriented environment for modeling complex physical systems that can be described by differential-algebraic equations. After a brief overview of SPARK, we describe the use of computer algebra in SPARK`s symbolic interface, which generates solution code for equations that are entered in symbolic form. We also describe how the Lex/Yacc compiler-compiler is used to achieve important extensions to the SPARK simulation language, including parametrized macro objects and steady-state resetting of a dynamic simulation. The application of thesemore » methods to solving the partial differential equations for two-dimensional heat flow is illustrated.« less

Circular blurred shape model for multiclass symbol recognition.

PubMed

Escalera, Sergio; Fornés, Alicia; Pujol, Oriol; Lladós, Josep; Radeva, Petia

2011-04-01

In this paper, we propose a circular blurred shape model descriptor to deal with the problem of symbol detection and classification as a particular case of object recognition. The feature extraction is performed by capturing the spatial arrangement of significant object characteristics in a correlogram structure. The shape information from objects is shared among correlogram regions, where a prior blurring degree defines the level of distortion allowed in the symbol, making the descriptor tolerant to irregular deformations. Moreover, the descriptor is rotation invariant by definition. We validate the effectiveness of the proposed descriptor in both the multiclass symbol recognition and symbol detection domains. In order to perform the symbol detection, the descriptors are learned using a cascade of classifiers. In the case of multiclass categorization, the new feature space is learned using a set of binary classifiers which are embedded in an error-correcting output code design. The results over four symbol data sets show the significant improvements of the proposed descriptor compared to the state-of-the-art descriptors. In particular, the results are even more significant in those cases where the symbols suffer from elastic deformations.

"Thank You, Black Twitter": State Violence, Digital Counterpublics, and Pedagogies of Resistance

ERIC Educational Resources Information Center

Hill, Marc Lamont

2018-01-01

In this article, I examine the role of Black Twitter as a "digital counterpublic" that enables critical pedagogy, political organizing, and both symbolic and material forms of resistance to anti-Black state violence within the United States. Focusing primarily on post-Ferguson events, I spotlight the ways that Black people have used…

Effects of a Digital Intervention on the Development of Algebraic Expertise

ERIC Educational Resources Information Center

Bokhove, Christian; Drijvers, Paul

2012-01-01

In this article we report on the effects of a digital intervention on the development of algebraic expertise of 17-18 year old students in the Netherlands. The question to be answered was whether the intervention would be effective and what factors influenced the outcome. With notions of formative assessment and symbol sense as guiding theoretical…

Symbolic Violence and Diversity in the Digital Age: The Genesis of a New Lexicon

ERIC Educational Resources Information Center

Benavidez, Max

2011-01-01

This dissertation examines the nexus of communication, diversity, and policy setting in major institutions--higher education, the media, and government--in an historical era when the Internet, social networks, mobile devices, and other forms of digital media define the times. The ultimate aim is to develop a new, conditional lexicon that provides…

Integration of symbolic and algorithmic hardware and software for the automation of space station subsystems

NASA Technical Reports Server (NTRS)

Gregg, Hugh; Healey, Kathleen; Hack, Edmund; Wong, Carla

1987-01-01

Expert systems that require access to data bases, complex simulations and real time instrumentation have both symbolic as well as algorithmic computing needs. These needs could both be met using a general computing workstation running both symbolic and algorithmic code, or separate, specialized computers networked together. The later approach was chosen to implement TEXSYS, the thermal expert system, developed to demonstrate the ability of an expert system to autonomously control the thermal control system of the space station. TEXSYS has been implemented on a Symbolics workstation, and will be linked to a microVAX computer that will control a thermal test bed. Integration options are explored and several possible solutions are presented.

Pagan symbols associated with the female anatomy in the Medici Chapel by Michelangelo Buonarroti.

PubMed

De Campos, Deivis; Oxley Da Rocha, Andrea; De Oliveira Lemos, Rodrigo; Malysz, Tais; Antonio Bonatto-Costa, João; Pereira Jotz, Geraldo; Pinto De Oliveira Junior, Lino; Da Costa Oliveira, Miriam

2017-07-01

Numerous studies have shown that many works of art from the Renaissance period contain hidden symbols and codes that could have religious, mathematical and/or pagan significance and even anatomical allusions. In this context, the present manuscript offers new evidence that the great genius of anatomy, Michelangelo Buonarroti (1475-1564), included pagan symbols associated with female anatomy in the funerary monuments found in the Sagrestia Nuova/Medici Chapel (1519-1533) in Florence, Italy. The interpretation of the symbols provided in this study will interest those with a passion for the history of anatomy. Clin. Anat. 30:572-577, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Gordon Research Conference on Computational Chemistry Held in Plymouth, New Hampshire on 4-8 July 1988

DTIC Science & Technology

1988-07-01

NUMBER(S) S. MONITORING ORGANIZATION REPORT NUMBER(S) _ R.TR- 90 - 0 4 70 6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING...University of Rhode Island Building 410 Kingston, RI 18195 Boiling AFB, DC 20332-6448 . Sa. NAME OF FUNDING / SPONSORING Sb. OFFICE SYMBOL 9, PROCUREMENT...AS RPT. 3 OTIC USERS UNCLASSIFIED 22a- NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) 22c OFFICE SYMBOL Dr Anthony J. Matuszko (202

What can eye movements tell us about Symbol Digit substitution by patients with schizophrenia?

PubMed

Elahipanah, Ava; Christensen, Bruce K; Reingold, Eyal M

2011-04-01

Substitution tests are sensitive to cognitive impairment and reliably discriminate patients with schizophrenia from healthy individuals better than most other neuropsychological instruments. However, due to their multifaceted nature, substitution test scores cannot pinpoint the specific cognitive deficits that lead to poor performance. The current study investigated eye movements during performance on a substitution test in order to better understand what aspect of substitution test performance underlies schizophrenia-related impairment. Twenty-five patients with schizophrenia and 25 healthy individuals performed a computerized version of the Symbol Digit Modalities Test while their eye movements were monitored. As expected, patients achieved lower overall performance scores. Moreover, analysis of participants' eye movements revealed that patients spent more time searching for the target symbol every time they visited the key area. Patients also made more visits to the key area for each response that they made. Regression analysis suggested that patients' impaired performance on substitution tasks is primarily related to a less efficient visual search and, secondarily, to impaired memory. Copyright © 2010 Elsevier B.V. All rights reserved.

Direct position determination for digital modulation signals based on improved particle swarm optimization algorithm

NASA Astrophysics Data System (ADS)

Yu, Wan-Ting; Yu, Hong-yi; Du, Jian-Ping; Wang, Ding

2018-04-01

The Direct Position Determination (DPD) algorithm has been demonstrated to achieve a better accuracy with known signal waveforms. However, the signal waveform is difficult to be completely known in the actual positioning process. To solve the problem, we proposed a DPD method for digital modulation signals based on improved particle swarm optimization algorithm. First, a DPD model is established for known modulation signals and a cost function is obtained on symbol estimation. Second, as the optimization of the cost function is a nonlinear integer optimization problem, an improved Particle Swarm Optimization (PSO) algorithm is considered for the optimal symbol search. Simulations are carried out to show the higher position accuracy of the proposed DPD method and the convergence of the fitness function under different inertia weight and population size. On the one hand, the proposed algorithm can take full advantage of the signal feature to improve the positioning accuracy. On the other hand, the improved PSO algorithm can improve the efficiency of symbol search by nearly one hundred times to achieve a global optimal solution.

The Statistical Loop Analyzer (SLA)

NASA Technical Reports Server (NTRS)

Lindsey, W. C.

1985-01-01

The statistical loop analyzer (SLA) is designed to automatically measure the acquisition, tracking and frequency stability performance characteristics of symbol synchronizers, code synchronizers, carrier tracking loops, and coherent transponders. Automated phase lock and system level tests can also be made using the SLA. Standard baseband, carrier and spread spectrum modulation techniques can be accomodated. Through the SLA's phase error jitter and cycle slip measurements the acquisition and tracking thresholds of the unit under test are determined; any false phase and frequency lock events are statistically analyzed and reported in the SLA output in probabilistic terms. Automated signal drop out tests can be performed in order to trouble shoot algorithms and evaluate the reacquisition statistics of the unit under test. Cycle slip rates and cycle slip probabilities can be measured using the SLA. These measurements, combined with bit error probability measurements, are all that are needed to fully characterize the acquisition and tracking performance of a digital communication system.

Does familiarity with computers affect computerized neuropsychological test performance?

PubMed

Iverson, Grant L; Brooks, Brian L; Ashton, V Lynn; Johnson, Lynda G; Gualtieri, C Thomas

2009-07-01

The purpose of this study was to determine whether self-reported computer familiarity is related to performance on computerized neurocognitive testing. Participants were 130 healthy adults who self-reported whether their computer use was "some" (n = 65) or "frequent" (n = 65). The two groups were individually matched on age, education, sex, and race. All completed the CNS Vital Signs (Gualtieri & Johnson, 2006b) computerized neurocognitive battery. There were significant differences on 6 of the 23 scores, including scores derived from the Symbol-Digit Coding Test, Stroop Test, and the Shifting Attention Test. The two groups were also significantly different on the Psychomotor Speed (Cohen's d = 0.37), Reaction Time (d = 0.68), Complex Attention (d = 0.40), and Cognitive Flexibility (d = 0.64) domain scores. People with "frequent" computer use performed better than people with "some" computer use on some tests requiring rapid visual scanning and keyboard work.

Parallel-Processing Equalizers for Multi-Gbps Communications

NASA Technical Reports Server (NTRS)

Gray, Andrew; Ghuman, Parminder; Hoy, Scott; Satorius, Edgar H.

2004-01-01

Architectures have been proposed for the design of frequency-domain least-mean-square complex equalizers that would be integral parts of parallel- processing digital receivers of multi-gigahertz radio signals and other quadrature-phase-shift-keying (QPSK) or 16-quadrature-amplitude-modulation (16-QAM) of data signals at rates of multiple gigabits per second. Equalizers as used here denotes receiver subsystems that compensate for distortions in the phase and frequency responses of the broad-band radio-frequency channels typically used to convey such signals. The proposed architectures are suitable for realization in very-large-scale integrated (VLSI) circuitry and, in particular, complementary metal oxide semiconductor (CMOS) application- specific integrated circuits (ASICs) operating at frequencies lower than modulation symbol rates. A digital receiver of the type to which the proposed architecture applies (see Figure 1) would include an analog-to-digital converter (A/D) operating at a rate, fs, of 4 samples per symbol period. To obtain the high speed necessary for sampling, the A/D and a 1:16 demultiplexer immediately following it would be constructed as GaAs integrated circuits. The parallel-processing circuitry downstream of the demultiplexer, including a demodulator followed by an equalizer, would operate at a rate of only fs/16 (in other words, at 1/4 of the symbol rate). The output from the equalizer would be four parallel streams of in-phase (I) and quadrature (Q) samples.

Symbolic play and language development.

PubMed

Orr, Edna; Geva, Ronny

2015-02-01

Symbolic play and language are known to be highly interrelated, but the developmental process involved in this relationship is not clear. Three hypothetical paths were postulated to explore how play and language drive each other: (1) direct paths, whereby initiation of basic forms in symbolic action or babbling, will be directly related to all later emerging language and motor outputs; (2) an indirect interactive path, whereby basic forms in symbolic action will be associated with more complex forms in symbolic play, as well as with babbling, and babbling mediates the relationship between symbolic play and speech; and (3) a dual path, whereby basic forms in symbolic play will be associated with basic forms of language, and complex forms of symbolic play will be associated with complex forms of language. We micro-coded 288 symbolic vignettes gathered during a yearlong prospective bi-weekly examination (N=14; from 6 to 18 months of age). Results showed that the age of initiation of single-object symbolic play correlates strongly with the age of initiation of later-emerging symbolic and vocal outputs; its frequency at initiation is correlated with frequency at initiation of babbling, later-emerging speech, and multi-object play in initiation. Results support the notion that a single-object play relates to the development of other symbolic forms via a direct relationship and an indirect relationship, rather than a dual-path hypothesis. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Recognizing Chinese characters in digital ink from non-native language writers using hierarchical models

NASA Astrophysics Data System (ADS)

Bai, Hao; Zhang, Xi-wen

2017-06-01

While Chinese is learned as a second language, its characters are taught step by step from their strokes to components, radicals to components, and their complex relations. Chinese Characters in digital ink from non-native language writers are deformed seriously, thus the global recognition approaches are poorer. So a progressive approach from bottom to top is presented based on hierarchical models. Hierarchical information includes strokes and hierarchical components. Each Chinese character is modeled as a hierarchical tree. Strokes in one Chinese characters in digital ink are classified with Hidden Markov Models and concatenated to the stroke symbol sequence. And then the structure of components in one ink character is extracted. According to the extraction result and the stroke symbol sequence, candidate characters are traversed and scored. Finally, the recognition candidate results are listed by descending. The method of this paper is validated by testing 19815 copies of the handwriting Chinese characters written by foreign students.

Cognitive factors affecting children's nonsymbolic and symbolic magnitude judgment abilities: A latent profile analysis.

PubMed

Chew, Cindy S; Forte, Jason D; Reeve, Robert A

2016-12-01

Early math abilities are claimed to be linked to magnitude representation ability. Some claim that nonsymbolic magnitude abilities scaffold the acquisition of symbolic (Arabic number) magnitude abilities and influence math ability. Others claim that symbolic magnitude abilities, and ipso facto math abilities, are independent of nonsymbolic abilities and instead depend on the ability to process number symbols (e.g., 2, 7). Currently, the issue of whether symbolic abilities are or are not related to nonsymbolic abilities, and the cognitive factors associated with nonsymbolic-symbolic relationships, remains unresolved. We suggest that different nonsymbolic-symbolic relationships reside within the general magnitude ability distribution and that different cognitive abilities are likely associated with these different relationships. We further suggest that the different nonsymbolic-symbolic relationships and cognitive abilities in combination differentially predict math abilities. To test these claims, we used latent profile analysis to identify nonsymbolic-symbolic judgment patterns of 124, 5- to 7-year-olds. We also assessed four cognitive factors (visuospatial working memory [VSWM], naming numbers, nonverbal IQ, and basic reaction time [RT]) and two math abilities (number transcoding and single-digit addition abilities). Four nonsymbolic-symbolic ability profiles were identified. Naming numbers, VSWM, and basic RT abilities were differentially associated with the different ability profiles and in combination differentially predicted math abilities. Findings show that different patterns of nonsymbolic-symbolic magnitude abilities can be identified and suggest that an adequate account of math development should specify the inter-relationship between cognitive factors and nonsymbolic-symbolic ability patterns. Copyright © 2016 Elsevier Inc. All rights reserved.

Error control techniques for satellite and space communications

NASA Technical Reports Server (NTRS)

Costello, Daniel J., Jr.

1989-01-01

Two aspects of the work for NASA are examined: the construction of multi-dimensional phase modulation trellis codes and a performance analysis of these codes. A complete list is contained of all the best trellis codes for use with phase modulation. LxMPSK signal constellations are included for M = 4, 8, and 16 and L = 1, 2, 3, and 4. Spectral efficiencies range from 1 bit/channel symbol (equivalent to rate 1/2 coded QPSK) to 3.75 bits/channel symbol (equivalent to 15/16 coded 16-PSK). The parity check polynomials, rotational invariance properties, free distance, path multiplicities, and coding gains are given for all codes. These codes are considered to be the best candidates for implementation of a high speed decoder for satellite transmission. The design of a hardware decoder for one of these codes, viz., the 16-state 3x8-PSK code with free distance 4.0 and coding gain 3.75 dB is discussed. An exhaustive simulation study of the multi-dimensional phase modulation trellis codes is contained. This study was motivated by the fact that coding gains quoted for almost all codes found in literature are in fact only asymptotic coding gains, i.e., the coding gain at very high signal to noise ratios (SNRs) or very low BER. These asymptotic coding gains can be obtained directly from a knowledge of the free distance of the code. On the other hand, real coding gains at BERs in the range of 10(exp -2) to 10(exp -6), where these codes are most likely to operate in a concatenated system, must be done by simulation.

Genenames.org: the HGNC and VGNC resources in 2017.

PubMed

Yates, Bethan; Braschi, Bryony; Gray, Kristian A; Seal, Ruth L; Tweedie, Susan; Bruford, Elspeth A

2017-01-04

The HUGO Gene Nomenclature Committee (HGNC) based at the European Bioinformatics Institute (EMBL-EBI) assigns unique symbols and names to human genes. Currently the HGNC database contains almost 40 000 approved gene symbols, over 19 000 of which represent protein-coding genes. In addition to naming genomic loci we manually curate genes into family sets based on shared characteristics such as homology, function or phenotype. We have recently updated our gene family resources and introduced new improved visualizations which can be seen alongside our gene symbol reports on our primary website http://www.genenames.org In 2016 we expanded our remit and formed the Vertebrate Gene Nomenclature Committee (VGNC) which is responsible for assigning names to vertebrate species lacking a dedicated nomenclature group. Using the chimpanzee genome as a pilot project we have approved symbols and names for over 14 500 protein-coding genes in chimpanzee, and have developed a new website http://vertebrate.genenames.org to distribute these data. Here, we review our online data and resources, focusing particularly on the improvements and new developments made during the last two years. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

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.

Detecting the borders between coding and non-coding DNA regions in prokaryotes based on recursive segmentation and nucleotide doublets statistics

PubMed Central

2012-01-01

Background Detecting the borders between coding and non-coding regions is an essential step in the genome annotation. And information entropy measures are useful for describing the signals in genome sequence. However, the accuracies of previous methods of finding borders based on entropy segmentation method still need to be improved. Methods In this study, we first applied a new recursive entropic segmentation method on DNA sequences to get preliminary significant cuts. A 22-symbol alphabet is used to capture the differential composition of nucleotide doublets and stop codon patterns along three phases in both DNA strands. This process requires no prior training datasets. Results Comparing with the previous segmentation methods, the experimental results on three bacteria genomes, Rickettsia prowazekii, Borrelia burgdorferi and E.coli, show that our approach improves the accuracy for finding the borders between coding and non-coding regions in DNA sequences. Conclusions This paper presents a new segmentation method in prokaryotes based on Jensen-Rényi divergence with a 22-symbol alphabet. For three bacteria genomes, comparing to A12_JR method, our method raised the accuracy of finding the borders between protein coding and non-coding regions in DNA sequences. PMID:23282225

Associations of Early Kidney Disease With Brain Magnetic Resonance Imaging and Cognitive Function in African Americans With Type 2 Diabetes Mellitus.

PubMed

Freedman, Barry I; Sink, Kaycee M; Hugenschmidt, Christina E; Hughes, Timothy M; Williamson, Jeff D; Whitlow, Christopher T; Palmer, Nicholette D; Miller, Michael E; Lovato, Laura C; Xu, Jianzhao; Smith, S Carrie; Launer, Lenore J; Barzilay, Joshua I; Cohen, Robert M; Sullivan, Mark D; Bryan, R Nick; Wagner, Benjamin C; Bowden, Donald W; Maldjian, Joseph A; Divers, Jasmin

2017-11-01

Relationships between early kidney disease, neurocognitive function, and brain anatomy are poorly defined in African Americans with type 2 diabetes mellitus (T2DM). Cross-sectional associations were assessed between cerebral anatomy and cognitive performance with estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (UACR) in African Americans with T2DM. African Americans with cognitive testing and cerebral magnetic resonance imaging (MRI) in the African American-Diabetes Heart Study Memory in Diabetes (AA-DHS MIND; n=512; 480 with MRI) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) MIND (n=484; 104 with MRI) studies. eGFR (CKD-EPI creatinine equation), spot UACR. MRI-based cerebral white matter volume (WMV), gray matter volume (GMV), and white matter lesion volume; cognitive performance (Mini-Mental State Examination, Digit Symbol Coding, Stroop Test, and Rey Auditory Verbal Learning Test). Multivariable models adjusted for age, sex, body mass index, scanner, intracranial volume, education, diabetes duration, hemoglobin A 1c concentration, low-density lipoprotein cholesterol concentration, smoking, hypertension, and cardiovascular disease were used to test for associations between kidney phenotypes and the brain in each study; a meta-analysis was performed. Mean participant age was 60.1±7.9 (SD) years; diabetes duration, 12.1±7.7 years; hemoglobin A 1c concentration, 8.3%±1.7%; eGFR, 88.7±21.6mL/min/1.73m 2 ; and UACR, 119.2±336.4mg/g. In the fully adjusted meta-analysis, higher GMV associated with lower UACR (P<0.05), with a trend toward association with higher eGFR. Higher white matter lesion volume was associated with higher UACR (P<0.05) and lower eGFR (P<0.001). WMV was not associated with either kidney parameter. Higher UACR was associated with lower Digit Symbol Coding performance (P<0.001) and a trend toward association with higher Stroop interference; eGFR was not associated with cognitive tests. Cross-sectional; single UACR measurement. In African Americans with T2DM, mildly high UACR and mildly low eGFR were associated with smaller GMV and increased white matter lesion volume. UACR was associated with poorer processing speed and working memory. Copyright © 2017 National Kidney Foundation, Inc. All rights reserved.

A general magnitude system in human adults: Evidence from a subliminal priming paradigm.

PubMed

Lourenco, Stella F; Ayzenberg, Vladislav; Lyu, Jennifer

2016-08-01

Despite general agreement that number and other magnitudes share analog format, there is disagreement about the extent to which representations of numerical and non-numerical magnitude recruit common cognitive and neural resources. Cross-dimensional interactions between number and other magnitudes on Stroop-like tasks have been taken as evidence for integration across magnitudes, but such effects are subject to alternative interpretations that allow for differentiated representations. Here we use a subliminal priming paradigm to test for interactions between different magnitudes (number and area) when one magnitude is not consciously detectable. Across two experiments, we first provide evidence for the feasibility of this paradigm by demonstrating that transfer occurs within the dimension of number; that is, symbolic numerals (Arabic digits) that were subliminally primed affected judgments of non-symbolic numerosities in target displays. Crucially, we also found transfer across magnitudes-from subliminally primed numerals to target displays of cumulative surface area whether participants made an ordinal judgment (i.e., "which array is larger in area?") or judged whether two arrays were the same or different in area. These findings suggest that representations of number and area are not fully differentiated. Moreover, they provide unique support for a general magnitude system that includes direct connections, or overlap, between the neural codes for numerical and non-numerical magnitudes. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Identification of special quality eggs with NIR spectroscopy technology based on symbol entropy feature extraction method].

PubMed

Zhao, Yong; Hong, Wen-Xue

2011-11-01

Fast, nondestructive and accurate identification of special quality eggs is an urgent problem. The present paper proposed a new feature extraction method based on symbol entropy to identify near infrared spectroscopy of special quality eggs. The authors selected normal eggs, free range eggs, selenium-enriched eggs and zinc-enriched eggs as research objects and measured the near-infrared diffuse reflectance spectra in the range of 12 000-4 000 cm(-1). Raw spectra were symbolically represented with aggregation approximation algorithm and symbolic entropy was extracted as feature vector. An error-correcting output codes multiclass support vector machine classifier was designed to identify the spectrum. Symbolic entropy feature is robust when parameter changed and the highest recognition rate reaches up to 100%. The results show that the identification method of special quality eggs using near-infrared is feasible and the symbol entropy can be used as a new feature extraction method of near-infrared spectra.

A Synchronous Digital Duplexing Technique for OFDMA-Based Indoor Communications

NASA Astrophysics Data System (ADS)

Park, Chang-Hwan; Ko, Yo-Han; Kim, Yeong-Jun; Park, Kyung-Won; Jeon, Won-Gi; Paik, Jong-Ho; Lee, Seok-Pil; Cho, Yong-Soo

In this paper, we propose a new digital duplexing scheme, called synchronous digital duplexing (SDD), which can increase data efficiency and flexibility of resource by transmitting uplink signal and downlink signal simultaneously in wireless communication. In order to transmit uplink and downlink signals simultaneously, the proposed SDD obtains mutual information among subscriber stations (SSs) with a mutual ranging symbol. This information is used for selection of transmission time, decision on cyclic suffix (CS) insertion, determination of CS length, and re-establishment of FFT starting point.

SYMBOD - A computer program for the automatic generation of symbolic equations of motion for systems of hinge-connected rigid bodies

NASA Technical Reports Server (NTRS)

Macala, G. A.

1983-01-01

A computer program is described that can automatically generate symbolic equations of motion for systems of hinge-connected rigid bodies with tree topologies. The dynamical formulation underlying the program is outlined, and examples are given to show how a symbolic language is used to code the formulation. The program is applied to generate the equations of motion for a four-body model of the Galileo spacecraft. The resulting equations are shown to be a factor of three faster in execution time than conventional numerical subroutines.

genenames.org: the HGNC resources in 2011

PubMed Central

Seal, Ruth L.; Gordon, Susan M.; Lush, Michael J.; Wright, Mathew W.; Bruford, Elspeth A.

2011-01-01

The HUGO Gene Nomenclature Committee (HGNC) aims to assign a unique gene symbol and name to every human gene. The HGNC database currently contains almost 30 000 approved gene symbols, over 19 000 of which represent protein-coding genes. The public website, www.genenames.org, displays all approved nomenclature within Symbol Reports that contain data curated by HGNC editors and links to related genomic, phenotypic and proteomic information. Here we describe improvements to our resources, including a new Quick Gene Search, a new List Search, an integrated HGNC BioMart and a new Statistics and Downloads facility. PMID:20929869

Integration of symbolic and algorithmic hardware and software for the automation of space station subsystems

NASA Technical Reports Server (NTRS)

Gregg, Hugh; Healey, Kathleen; Hack, Edmund; Wong, Carla

1987-01-01

Traditional expert systems, such as diagnostic and training systems, interact with users only through a keyboard and screen, and are usually symbolic in nature. Expert systems that require access to data bases, complex simulations and real-time instrumentation have both symbolic as well as algorithmic computing needs. These needs could both be met using a general purpose workstation running both symbolic and algorithmic code, or separate, specialized computers networked together. The latter approach was chosen to implement TEXSYS, the thermal expert system, developed by NASA Ames Research Center in conjunction with Johnson Space Center to demonstrate the ability of an expert system to autonomously monitor the thermal control system of the space station. TEXSYS has been implemented on a Symbolics workstation, and will be linked to a microVAX computer that will control a thermal test bed. This paper will explore the integration options, and present several possible solutions.

Analysis of Champus Per Capita Mental Health Expenditures and Utilization for Beneficiaries Less Than Eighteen Years

DTIC Science & Technology

1991-04-01

and (If applicable) Clinical Investigation Icty HSAD -A HQ HSC/HSCL-M 6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code...NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) 22c. OFFICE SYMBOL Dr. Scott A. Optenberg, GM-14 (512) 221-5880 HSAD -A DD Form

"Coded and Uncoded Error Feedback: Effects on Error Frequencies in Adult Colombian EFL Learners' Writing"

ERIC Educational Resources Information Center

Sampson, Andrew

2012-01-01

This paper reports on a small-scale study into the effects of uncoded correction (writing the correct forms above each error) and coded annotations (writing symbols that encourage learners to self-correct) on Colombian university-level EFL learners' written work. The study finds that while both coded annotations and uncoded correction appear to…

Performance of Low-Density Parity-Check Coded Modulation

NASA Astrophysics Data System (ADS)

Hamkins, J.

2011-02-01

This article presents the simulated performance of a family of nine AR4JA low-density parity-check (LDPC) codes when used with each of five modulations. In each case, the decoder inputs are codebit log-likelihood ratios computed from the received (noisy) modulation symbols using a general formula which applies to arbitrary modulations. Suboptimal soft-decision and hard-decision demodulators are also explored. Bit-interleaving and various mappings of bits to modulation symbols are considered. A number of subtle decoder algorithm details are shown to affect performance, especially in the error floor region. Among these are quantization dynamic range and step size, clipping degree-one variable nodes, "Jones clipping" of variable nodes, approximations of the min* function, and partial hard-limiting messages from check nodes. Using these decoder optimizations, all coded modulations simulated here are free of error floors down to codeword error rates below 10^{-6}. The purpose of generating this performance data is to aid system engineers in determining an appropriate code and modulation to use under specific power and bandwidth constraints, and to provide information needed to design a variable/adaptive coded modulation (VCM/ACM) system using the AR4JA codes. IPNPR Volume 42-185 Tagged File.txt

Determination of eigenvalues of dynamical systems by symbolic computation

NASA Technical Reports Server (NTRS)

Howard, J. C.

1982-01-01

A symbolic computation technique for determining the eigenvalues of dynamical systems is described wherein algebraic operations, symbolic differentiation, matrix formulation and inversion, etc., can be performed on a digital computer equipped with a formula-manipulation compiler. An example is included that demonstrates the facility with which the system dynamics matrix and the control distribution matrix from the state space formulation of the equations of motion can be processed to obtain eigenvalue loci as a function of a system parameter. The example chosen to demonstrate the technique is a fourth-order system representing the longitudinal response of a DC 8 aircraft to elevator inputs. This simplified system has two dominant modes, one of which is lightly damped and the other well damped. The loci may be used to determine the value of the controlling parameter that satisfied design requirements. The results were obtained using the MACSYMA symbolic manipulation system.

Thermoelectric pump performance analysis computer code

NASA Technical Reports Server (NTRS)

Johnson, J. L.

1973-01-01

A computer program is presented that was used to analyze and design dual-throat electromagnetic dc conduction pumps for the 5-kwe ZrH reactor thermoelectric system. In addition to a listing of the code and corresponding identification of symbols, the bases for this analytical model are provided.

Light Infantry in the Defense of Urban Europe.

DTIC Science & Technology

1986-12-14

if applicable) 6c. ADDRESS (City, State, and ZIP Code ) 7b. ADDRESS (City, State, and ZIP Code ) Fort Leavenworth, Kansas 66027-6900 Ba. NAME OF FUNDING...SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable) Sc. ADDRESS (City, State, and ZIP Code ) 10...PAGE COUNT wo - EFROM TO144 16. SUPPLEMENTARY NOTATION 17. COSATI CODES A*SUBJECT TERMS (Continue on reverse if necessary and identify by block

Taco De Sesos

ERIC Educational Resources Information Center

de la Loza, Sandra

2004-01-01

Taco de Sesos is a digitally animated fotonovella with the help of which the archetype of the "Maria" is explored. "La Maria" is represented as the heroic figure that quietly suffers a myriad of physical and symbolic violences.

39 CFR Appendix A to Part 121 - Tables Depicting Service Standard Day Ranges

Code of Federal Regulations, 2012 CFR

2012-07-01

... & USVI Periodicals 1 1-3 1 1-3 1-4 (AK) 11 (JNU) 11 (KTN) 1 (HI) 2 (GU) 1-4 10-11 10 8-10 Standard Mail 2 3 3-4 3-4 14 13 12 Package Services 1 2 2-3 2-3 12 11 11 AK = Alaska 3-digit ZIP Codes 995-997; JNU = Juneau AK 3-digit ZIP Code 998; KTN = Ketchikan AK 3-digit ZIP Code 999; HI = Hawaii 3-digit ZIP Codes...

39 CFR Appendix A to Part 121 - Tables Depicting Service Standard Day Ranges

Code of Federal Regulations, 2013 CFR

2013-07-01

... & USVI Periodicals 1 1-3 1 1-3 1-4 (AK) 11 (JNU) 11 (KTN) 1 (HI) 2 (GU) 1-4 10-11 10 8-10 Standard Mail 2 3 3-4 3-4 14 13 12 Package Services 1 2 2-3 2-3 12 11 11 AK = Alaska 3-digit ZIP Codes 995-997; JNU = Juneau AK 3-digit ZIP Code 998; KTN = Ketchikan AK 3-digit ZIP Code 999; HI = Hawaii 3-digit ZIP Codes...

Effects of symbol type and numerical distance on the human event-related potential.

PubMed

Jiang, Ting; Qiao, Sibing; Li, Jin; Cao, Zhongyu; Gao, Xuefei; Song, Yan; Xue, Gui; Dong, Qi; Chen, Chuansheng

2010-01-01

This study investigated the influence of the symbol type and numerical distance of numbers on the amplitudes and peak latencies of event-related potentials (ERPs). Our aim was to (1) determine the point in time of magnitude information access in visual number processing; and (2) identify at what stage the advantage of Arabic digits over Chinese verbal numbers occur. ERPs were recorded from 64 scalp sites while subjects (n=26) performed a classification task. Results showed that larger ERP amplitudes were elicited by numbers with distance-close condition in comparison to distance-far condition in the VPP component over centro-frontal sites. Furthermore, the VPP latency varied as a function of the symbol type, but the N170 did not. Such results demonstrate that magnitude information access takes place as early as 150 ms after onset of visual number stimuli and the advantage of Arabic digits over verbal numbers should be localized to the VPP component. We establish the VPP component as a critical ERP component to report in studies of numerical cognition and our results call into question the N170/VPP association hypothesis and the serial-stage model of visual number comparison processing.

A digital clock recovery algorithm based on chromatic dispersion and polarization mode dispersion feedback dual phase detection for coherent optical transmission systems

NASA Astrophysics Data System (ADS)

Liu, Bo; Xin, Xiangjun; Zhang, Lijia; Wang, Fu; Zhang, Qi

2018-02-01

A new feedback symbol timing recovery technique using timing estimation joint equalization is proposed for digital receivers with two samples/symbol or higher sampling rate. Different from traditional methods, the clock recovery algorithm in this paper adopts another algorithm distinguishing the phases of adjacent symbols, so as to accurately estimate the timing offset based on the adjacent signals with the same phase. The addition of the module for eliminating phase modulation interference before timing estimation further reduce the variance, thus resulting in a smoothed timing estimate. The Mean Square Error (MSE) and Bit Error Rate (BER) of the resulting timing estimate are simulated to allow a satisfactory estimation performance. The obtained clock tone performance is satisfactory for MQAM modulation formats and the Roll-off Factor (ROF) close to 0. In the back-to-back system, when ROF= 0, the maximum of MSE obtained with the proposed approach reaches 0 . 0125. After 100-km fiber transmission, BER decreases to 10-3 with ROF= 0 and OSNR = 11 dB. With the increase in ROF, the performances of MSE and BER become better.

Method and apparatus for data decoding and processing

DOEpatents

Hunter, Timothy M.; Levy, Arthur J.

1992-01-01

A system and technique is disclosed for automatically controlling the decoding and digitizaiton of an analog tape. The system includes the use of a tape data format which includes a plurality of digital codes recorded on the analog tape in a predetermined proximity to a period of recorded analog data. The codes associated with each period of analog data include digital identification codes prior to the analog data, a start of data code coincident with the analog data recording, and an end of data code subsequent to the associated period of recorded analog data. The formatted tape is decoded in a processing and digitization system which includes an analog tape player coupled to a digitizer to transmit analog information from the recorded tape over at least one channel to the digitizer. At the same time, the tape player is coupled to a decoder and interface system which detects and decodes the digital codes on the tape corresponding to each period of recorded analog data and controls tape movement and digitizer initiation in response to preprogramed modes. A host computer is also coupled to the decoder and interface system and the digitizer and programmed to initiate specific modes of data decoding through the decoder and interface system including the automatic compilation and storage of digital identification information and digitized data for the period of recorded analog data corresponding to the digital identification data, compilation and storage of selected digitized data representing periods of recorded analog data, and compilation of digital identification information related to each of the periods of recorded analog data.

On the decoding process in ternary error-correcting output codes.

PubMed

Escalera, Sergio; Pujol, Oriol; Radeva, Petia

2010-01-01

A common way to model multiclass classification problems is to design a set of binary classifiers and to combine them. Error-Correcting Output Codes (ECOC) represent a successful framework to deal with these type of problems. Recent works in the ECOC framework showed significant performance improvements by means of new problem-dependent designs based on the ternary ECOC framework. The ternary framework contains a larger set of binary problems because of the use of a "do not care" symbol that allows us to ignore some classes by a given classifier. However, there are no proper studies that analyze the effect of the new symbol at the decoding step. In this paper, we present a taxonomy that embeds all binary and ternary ECOC decoding strategies into four groups. We show that the zero symbol introduces two kinds of biases that require redefinition of the decoding design. A new type of decoding measure is proposed, and two novel decoding strategies are defined. We evaluate the state-of-the-art coding and decoding strategies over a set of UCI Machine Learning Repository data sets and into a real traffic sign categorization problem. The experimental results show that, following the new decoding strategies, the performance of the ECOC design is significantly improved.

Fundamental Studies in the Molecular Basis of Laser Induced Retinal Damage

DTIC Science & Technology

1988-01-01

Cornell University School of Applied & Engineering Physics Ithaca, NY 14853 DOD DISTRIBUTION STATEMENT Approved for public release; distribution unlimited...Code) 7b. ADDRESS (City, State, and ZIP Code) School of Applied & Engineering Physics Ithaca, NY 14853 8a. NAME OF FUNDING/SPONSORING Bb. OFFICE SYMBOL

Color Coding of Circuit Quantities in Introductory Circuit Analysis Instruction

ERIC Educational Resources Information Center

Reisslein, Jana; Johnson, Amy M.; Reisslein, Martin

2015-01-01

Learning the analysis of electrical circuits represented by circuit diagrams is often challenging for novice students. An open research question in electrical circuit analysis instruction is whether color coding of the mathematical symbols (variables) that denote electrical quantities can improve circuit analysis learning. The present study…

Integration of symbolic and algorithmic hardware and software for the automation of space station subsystems

NASA Technical Reports Server (NTRS)

Gregg, Hugh; Healey, Kathleen; Hack, Edmund; Wong, Carla

1988-01-01

Expert systems that require access to data bases, complex simulations and real time instrumentation have both symbolic and algorithmic needs. Both of these needs could be met using a general purpose workstation running both symbolic and algorithmic codes, or separate, specialized computers networked together. The later approach was chosen to implement TEXSYS, the thermal expert system, developed by the NASA Ames Research Center in conjunction with the Johnson Space Center to demonstrate the ability of an expert system to autonomously monitor the thermal control system of the space station. TEXSYS has been implemented on a Symbolics workstation, and will be linked to a microVAX computer that will control a thermal test bed. The integration options and several possible solutions are presented.

Graphical user interfaces for symbol-oriented database visualization and interaction

NASA Astrophysics Data System (ADS)

Brinkschulte, Uwe; Siormanolakis, Marios; Vogelsang, Holger

1997-04-01

In this approach, two basic services designed for the engineering of computer based systems are combined: a symbol-oriented man-machine-service and a high speed database-service. The man-machine service is used to build graphical user interfaces (GUIs) for the database service; these interfaces are stored using the database service. The idea is to create a GUI-builder and a GUI-manager for the database service based upon the man-machine service using the concept of symbols. With user-definable and predefined symbols, database contents can be visualized and manipulated in a very flexible and intuitive way. Using the GUI-builder and GUI-manager, a user can build and operate its own graphical user interface for a given database according to its needs without writing a single line of code.

System for Computer Automated Typesetting ((SCAT) of Computer Authored Texts.

DTIC Science & Technology

1980-07-01

95 APPENDIX D - CODE SETS. .. .. .... ...... ..... ....... 101 APPENDIX E - SAMPLE OF PROGRAMMED INSTRUCTION DEMONSTRATING THE USE OF TYPOGRAPHY ...demonstrates the quality of typography available. 1discussion of typesetting in general is beyond the scope of this report. The reader not familiar with...INSTRUCTION DEMONSTRATING THE USE OF TYPOGRAPHY 107 1’p TAEG Report No. 8 PRESENT WEATHER SYMBOLS Symbolic Numbers NWS-AG-A-090 November 1979 This program was

Evaluating Varied Label Designs for Use with Medical Devices: Optimized Labels Outperform Existing Labels in the Correct Selection of Devices and Time to Select.

PubMed

Bix, Laura; Seo, Do Chan; Ladoni, Moslem; Brunk, Eric; Becker, Mark W

2016-01-01

Effective standardization of medical device labels requires objective study of varied designs. Insufficient empirical evidence exists regarding how practitioners utilize and view labeling. Measure the effect of graphic elements (boxing information, grouping information, symbol use and color-coding) to optimize a label for comparison with those typical of commercial medical devices. Participants viewed 54 trials on a computer screen. Trials were comprised of two labels that were identical with regard to graphics, but differed in one aspect of information (e.g., one had latex, the other did not). Participants were instructed to select the label along a given criteria (e.g., latex containing) as quickly as possible. Dependent variables were binary (correct selection) and continuous (time to correct selection). Eighty-nine healthcare professionals were recruited at Association of Surgical Technologists (AST) conferences, and using a targeted e-mail of AST members. Symbol presence, color coding and grouping critical pieces of information all significantly improved selection rates and sped time to correct selection (α = 0.05). Conversely, when critical information was graphically boxed, probability of correct selection and time to selection were impaired (α = 0.05). Subsequently, responses from trials containing optimal treatments (color coded, critical information grouped with symbols) were compared to two labels created based on a review of those commercially available. Optimal labels yielded a significant positive benefit regarding the probability of correct choice ((P<0.0001) LSM; UCL, LCL: 97.3%; 98.4%, 95.5%)), as compared to the two labels we created based on commercial designs (92.0%; 94.7%, 87.9% and 89.8%; 93.0%, 85.3%) and time to selection. Our study provides data regarding design factors, namely: color coding, symbol use and grouping of critical information that can be used to significantly enhance the performance of medical device labels.

48 CFR 304.7001 - Numbering acquisitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... numeric identification code assigned by ASFR/OGAPA/DA to the contracting office within the servicing... following: (1) The three-digit identification code (HHS) of the Department. (2) A one-digit numeric...: P SAMHSA: S (3) The three-digit numeric identification code assigned by ASFR/OGAPA/DA to the...

48 CFR 304.7001 - Numbering acquisitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... numeric identification code assigned by ASFR/OGAPA/DA to the contracting office within the servicing... following: (1) The three-digit identification code (HHS) of the Department. (2) A one-digit numeric...: P SAMHSA: S (3) The three-digit numeric identification code assigned by ASFR/OGAPA/DA to the...

48 CFR 304.7001 - Numbering acquisitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... numeric identification code assigned by ASFR/OGAPA/DA to the contracting office within the servicing... following: (1) The three-digit identification code (HHS) of the Department. (2) A one-digit numeric...: P SAMHSA: S (3) The three-digit numeric identification code assigned by ASFR/OGAPA/DA to the...

The Coding of Biological Information: From Nucleotide Sequence to Protein Recognition

NASA Astrophysics Data System (ADS)

Štambuk, Nikola

The paper reviews the classic results of Swanson, Dayhoff, Grantham, Blalock and Root-Bernstein, which link genetic code nucleotide patterns to the protein structure, evolution and molecular recognition. Symbolic representation of the binary addresses defining particular nucleotide and amino acid properties is discussed, with consideration of: structure and metric of the code, direct correspondence between amino acid and nucleotide information, and molecular recognition of the interacting protein motifs coded by the complementary DNA and RNA strands.

Joint Source-Channel Coding by Means of an Oversampled Filter Bank Code

NASA Astrophysics Data System (ADS)

Marinkovic, Slavica; Guillemot, Christine

2006-12-01

Quantized frame expansions based on block transforms and oversampled filter banks (OFBs) have been considered recently as joint source-channel codes (JSCCs) for erasure and error-resilient signal transmission over noisy channels. In this paper, we consider a coding chain involving an OFB-based signal decomposition followed by scalar quantization and a variable-length code (VLC) or a fixed-length code (FLC). This paper first examines the problem of channel error localization and correction in quantized OFB signal expansions. The error localization problem is treated as an[InlineEquation not available: see fulltext.]-ary hypothesis testing problem. The likelihood values are derived from the joint pdf of the syndrome vectors under various hypotheses of impulse noise positions, and in a number of consecutive windows of the received samples. The error amplitudes are then estimated by solving the syndrome equations in the least-square sense. The message signal is reconstructed from the corrected received signal by a pseudoinverse receiver. We then improve the error localization procedure by introducing a per-symbol reliability information in the hypothesis testing procedure of the OFB syndrome decoder. The per-symbol reliability information is produced by the soft-input soft-output (SISO) VLC/FLC decoders. This leads to the design of an iterative algorithm for joint decoding of an FLC and an OFB code. The performance of the algorithms developed is evaluated in a wavelet-based image coding system.

Approximate number sense, symbolic number processing, or number-space mappings: what underlies mathematics achievement?

PubMed

Sasanguie, Delphine; Göbel, Silke M; Moll, Kristina; Smets, Karolien; Reynvoet, Bert

2013-03-01

In this study, the performance of typically developing 6- to 8-year-old children on an approximate number discrimination task, a symbolic comparison task, and a symbolic and nonsymbolic number line estimation task was examined. For the first time, children's performances on these basic cognitive number processing tasks were explicitly contrasted to investigate which of them is the best predictor of their future mathematical abilities. Math achievement was measured with a timed arithmetic test and with a general curriculum-based math test to address the additional question of whether the predictive association between the basic numerical abilities and mathematics achievement is dependent on which math test is used. Results revealed that performance on both mathematics achievement tests was best predicted by how well childrencompared digits. In addition, an association between performance on the symbolic number line estimation task and math achievement scores for the general curriculum-based math test measuring a broader spectrum of skills was found. Together, these results emphasize the importance of learning experiences with symbols for later math abilities. Copyright © 2012 Elsevier Inc. All rights reserved.

A Simulation System for Validating the Analytical Prediction of Performance of the Convolutional Encoded and Symbol Interleaved TDRSS S-band Return Link Service in a Pulsed RFI Environment

NASA Technical Reports Server (NTRS)

1981-01-01

A hardware integrated convolutional coding/symbol interleaving and integrated symbol deinterleaving/Viterbi decoding simulation system is described. Validation on the system of the performance of the TDRSS S-band return link with BPSK modulation, operating in a pulsed RFI environment is included. The system consists of three components, the Fast Linkabit Error Rate Tester (FLERT), the Transition Probability Generator (TPG), and a modified LV7017B which includes rate 1/3 capability as well as a periodic interleaver/deinterleaver. Operating and maintenance manuals for each of these units are included.

Digital plus analog output encoder

NASA Technical Reports Server (NTRS)

Hafle, R. S. (Inventor)

1976-01-01

The disclosed encoder is adapted to produce both digital and analog output signals corresponding to the angular position of a rotary shaft, or the position of any other movable member. The digital signals comprise a series of binary signals constituting a multidigit code word which defines the angular position of the shaft with a degree of resolution which depends upon the number of digits in the code word. The basic binary signals are produced by photocells actuated by a series of binary tracks on a code disc or member. The analog signals are in the form of a series of ramp signals which are related in length to the least significant bit of the digital code word. The analog signals are derived from sine and cosine tracks on the code disc.

Assessment of the knowledge of graphical symbols labelled on malaria rapid diagnostic tests in four international settings.

PubMed

Hermans, Veerle; Monzote, Lianet; Van den Sande, Björn; Mukadi, Pierre; Sopheak, Thai; Gillet, Philippe; Jacobs, Jan

2011-11-02

Graphical symbols on in vitro diagnostics (IVD symbols) replace the need for text in different languages and are used on malaria rapid diagnostic tests (RDTs) marketed worldwide. The present study assessed the comprehension of IVD symbols labelled on malaria RDT kits among laboratory staff in four different countries. Participants (n = 293) in Belgium (n = 96), the Democratic Republic of the Congo (DRC, n = 87), Cambodia (n = 59) and Cuba (n = 51) were presented with an anonymous questionnaire with IVD symbols extracted from ISO 15223 and EN 980 presented as stand-alone symbols (n = 18) and in context (affixed on RDT packages, n = 16). Responses were open-ended and scored for correctness by local professionals. Presented as stand-alone, three and five IVD symbols were correctly scored for comprehension by 67% and 50% of participants; when contextually presented, five and seven symbols reached the 67% and 50% correct score respectively. 'Batch code' scored best (correctly scored by 71.3% of participants when presented as stand-alone), 'Authorized representative in the European Community' scored worst (1.4% correct). Another six IVD symbols were scored correctly by less than 10% of participants: 'Do not reuse', 'In vitro diagnostic medical device', 'Sufficient for', 'Date of manufacture', 'Authorised representative in EC', and 'Do not use if package is damaged'. Participants in Belgium and Cuba both scored six symbols above the 67% criterion, participants from DRC and Cambodia scored only two and one symbols above this criterion. Low correct scores were observed for safety-related IVD symbols, such as for 'Biological Risk' (42.7%) and 'Do not reuse' (10.9%). Comprehension of IVD symbols on RDTs among laboratory staff in four international settings was unsatisfactory. Administrative and outreach procedures should be undertaken to assure their acquaintance by end-users.

Subpicosecond Optical Digital Computation Using Conjugate Parametric Generators

DTIC Science & Technology

1989-03-31

Using Phase Conjugate Farametric Generators ..... 12. PERSONAL AUTHOR(S) Alfano, Robert- Eichmann . George; Dorsinville. Roger! Li. Yao 13a. TYPE OF...conjugation-based optical residue arithmetic processor," Y. Li, G. Eichmann , R. Dorsinville, and R. R. Alfano, Opt. Lett. 13, (1988). [2] "Parallel ultrafast...optical digital and symbolic computation via optical phase conjugation," Y. Li, G. Eichmann , R. Dorsinville, Appl. Opt. 27, 2025 (1988). [3

Intensity of recreational physical activity throughout life and later life cognitive functioning in women.

PubMed

Tierney, Mary C; Moineddin, Rahim; Morra, Angela; Manson, Judith; Blake, Jennifer

2010-01-01

Long-term physical activity may affect risk of cognitive impairment but few studies have examined later life cognition in relation to intensity of life-long physical activity. We examined the associations between the intensity of long-term recreational physical activity and neuropsychological functioning in 90 healthy postmenopausal women on tests found to be useful in the early identification of dementia. Information was collected about their participation in strenuous and moderate activities between high school and menopause. Summary measures of long-term strenuous and moderate activity were constructed for each participant. All analyses were adjusted for relevant covariates. The six linear regression analyses showed significant positive associations between moderate activity and Wechsler Adult Intelligence Scale Revised (WAIS-R), Digit Span backward, WAIS-R Digit Symbol, and Trail Making Test Part B. Significant negative relationships were found between strenuous activity and Rey Auditory Verbal Learning Test delayed verbal recall, Complex Figure Test delayed visual memory, WAIS-R Digit Span backward, category fluency, and WAIS-R Digit Symbol. The associations found in the present study suggest that while moderate activity may be protective, long-term strenuous activity before menopause may lower cognitive performance later in life. These results support further investigation of the effects of life-long exercise intensity on cognition in later life.

Automating FEA programming

NASA Technical Reports Server (NTRS)

Sharma, Naveen

1992-01-01

In this paper we briefly describe a combined symbolic and numeric approach for solving mathematical models on parallel computers. An experimental software system, PIER, is being developed in Common Lisp to synthesize computationally intensive and domain formulation dependent phases of finite element analysis (FEA) solution methods. Quantities for domain formulation like shape functions, element stiffness matrices, etc., are automatically derived using symbolic mathematical computations. The problem specific information and derived formulae are then used to generate (parallel) numerical code for FEA solution steps. A constructive approach to specify a numerical program design is taken. The code generator compiles application oriented input specifications into (parallel) FORTRAN77 routines with the help of built-in knowledge of the particular problem, numerical solution methods and the target computer.

NMCS Information Processing System 360 Formatted File System (NIPS 360 FFS). Users Manual. Volume 1. Introduction to File Concepts

DTIC Science & Technology

1978-09-01

input source language (other than ?S). Used in double form, negates an FFT spcification for a subroutine. / (Slash) Used to separate numeric digits (V-l...1) represents the digits 1-999 and also digits followed by a letter, e.g., LINE1OA ’. Th, E311owing name prefiKes are not allowed: PSSQ, VSEr, VSZ...b ZERO OUT 6 LA 6,12 (6) ADD 12 TO 6 PUT IN REG b 4’MOVF INPUT DATE rC WORK APEA, REFORMAT DD AND YY 0C)NVERr TWO DIGIT MONTH TO SYMBOLIC THREE

Age-related slowing of digit symbol substitution revisited: what do longitudinal age changes reflect?

PubMed

MacDonald, Stuart W S; Hultsch, David F; Strauss, Esther; Dixon, Roger A

2003-05-01

A previous investigation reported that cross-sectional age differences in Digit Symbol Substitution (DSS) test performance reflect declines in perceptual processing speed. Support for the tenability of the processing speed hypothesis requires examining whether longitudinal age-related change in DSS performance is largely mediated by changes in speed. The present study used data from the Victoria Longitudinal Study to examine patterns and predictors of longitudinal change in DSS for 512 older adults (M(age) = 68.37 years, SD = 7.43). On the basis of multilevel modeling, baseline DSS performance was poorer for older participants and men, with longitudinal declines more pronounced with increasing age and decreasing speed. In contrast to the present cross-sectional findings, statistical control of change trajectories in perceptual speed using the same data did not substantially attenuate age changes. These discrepancies suggest different sources of variance may underlie cross-sectional age differences and longitudinal age changes for DSS.

Acta Aeronautica et Astronautica Sinica.

DTIC Science & Technology

1982-07-28

AERONAUTICA ET ASTRONAUTICA SINICA - <,y English pages: 212 _r Source : Acta Aeronautica et Astronautica Sinica, Vol. 2, Nr. 4, December 1981 , . pp. 1...ADVOCATED OR IMPLIED ARE THOSE OP THE SOURCE ANDDO NOT NECESSARILY REFLECT THE POSITION TRANSLATION DIVISION OR OPINION OF THE FOREnjN TECHNOLOGY DI...axial) solution section code 2 Lower Corner Symbols i code of sectional cylindrical coordinate system j,k radial and peripheral codes of solution

77 FR 77077 - Pesticide Product Registration; Receipt of Applications for New Uses

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-31

... affected entities may include: Crop production (NAICS code 111). Animal production (NAICS code 112). Food... File Symbol: 264-1049 and 72155- RNO. Docket ID Number: EPA-HQ-OPP-2012-0946. Applicant: Bayer CropScience, 2 T. W. Alexander Drive, P. O. Box 12014, Research Triangle Park, NC 27709. Active Ingredient...

Encoders for block-circulant LDPC codes

NASA Technical Reports Server (NTRS)

Divsalar, Dariush (Inventor); Abbasfar, Aliazam (Inventor); Jones, Christopher R. (Inventor); Dolinar, Samuel J. (Inventor); Thorpe, Jeremy C. (Inventor); Andrews, Kenneth S. (Inventor); Yao, Kung (Inventor)

2009-01-01

Methods and apparatus to encode message input symbols in accordance with an accumulate-repeat-accumulate code with repetition three or four are disclosed. Block circulant matrices are used. A first method and apparatus make use of the block-circulant structure of the parity check matrix. A second method and apparatus use block-circulant generator matrices.

Binary weight distributions of some Reed-Solomon codes

NASA Technical Reports Server (NTRS)

Pollara, F.; Arnold, S.

1992-01-01

The binary weight distributions of the (7,5) and (15,9) Reed-Solomon (RS) codes and their duals are computed using the MacWilliams identities. Several mappings of symbols to bits are considered and those offering the largest binary minimum distance are found. These results are then used to compute bounds on the soft-decoding performance of these codes in the presence of additive Gaussian noise. These bounds are useful for finding large binary block codes with good performance and for verifying the performance obtained by specific soft-coding algorithms presently under development.

Product code optimization for determinate state LDPC decoding in robust image transmission.

PubMed

Thomos, Nikolaos; Boulgouris, Nikolaos V; Strintzis, Michael G

2006-08-01

We propose a novel scheme for error-resilient image transmission. The proposed scheme employs a product coder consisting of low-density parity check (LDPC) codes and Reed-Solomon codes in order to deal effectively with bit errors. The efficiency of the proposed scheme is based on the exploitation of determinate symbols in Tanner graph decoding of LDPC codes and a novel product code optimization technique based on error estimation. Experimental evaluation demonstrates the superiority of the proposed system in comparison to recent state-of-the-art techniques for image transmission.

Information rates of probabilistically shaped coded modulation for a multi-span fiber-optic communication system with 64QAM

NASA Astrophysics Data System (ADS)

Fehenberger, Tobias

2018-02-01

This paper studies probabilistic shaping in a multi-span wavelength-division multiplexing optical fiber system with 64-ary quadrature amplitude modulation (QAM) input. In split-step fiber simulations and via an enhanced Gaussian noise model, three figures of merit are investigated, which are signal-to-noise ratio (SNR), achievable information rate (AIR) for capacity-achieving forward error correction (FEC) with bit-metric decoding, and the information rate achieved with low-density parity-check (LDPC) FEC. For the considered system parameters and different shaped input distributions, shaping is found to decrease the SNR by 0.3 dB yet simultaneously increases the AIR by up to 0.4 bit per 4D-symbol. The information rates of LDPC-coded modulation with shaped 64QAM input are improved by up to 0.74 bit per 4D-symbol, which is larger than the shaping gain when considering AIRs. This increase is attributed to the reduced coding gap of the higher-rate code that is used for decoding the nonuniform QAM input.

Developmental trajectories of children's symbolic numerical magnitude processing skills and associated cognitive competencies.

PubMed

Vanbinst, Kiran; Ceulemans, Eva; Peters, Lien; Ghesquière, Pol; De Smedt, Bert

2018-02-01

Although symbolic numerical magnitude processing skills are key for learning arithmetic, their developmental trajectories remain unknown. Therefore, we delineated during the first 3years of primary education (5-8years of age) groups with distinguishable developmental trajectories of symbolic numerical magnitude processing skills using a model-based clustering approach. Three clusters were identified and were labeled as inaccurate, accurate but slow, and accurate and fast. The clusters did not differ in age, sex, socioeconomic status, or IQ. We also tested whether these clusters differed in domain-specific (nonsymbolic magnitude processing and digit identification) and domain-general (visuospatial short-term memory, verbal working memory, and processing speed) cognitive competencies that might contribute to children's ability to (efficiently) process the numerical meaning of Arabic numerical symbols. We observed minor differences between clusters in these cognitive competencies except for verbal working memory for which no differences were observed. Follow-up analyses further revealed that the above-mentioned cognitive competencies did not merely account for the cluster differences in children's development of symbolic numerical magnitude processing skills, suggesting that other factors account for these individual differences. On the other hand, the three trajectories of symbolic numerical magnitude processing revealed remarkable and stable differences in children's arithmetic fact retrieval, which stresses the importance of symbolic numerical magnitude processing for learning arithmetic. Copyright © 2017 Elsevier Inc. All rights reserved.

Problem-Solving Under Time Constraints: Alternatives for the Commander’s Estimate

DTIC Science & Technology

1990-03-26

CHOOL OF ADVANCED MILITAR (If applicable) STUDIES, USAC&GSC IATZL-SWV 6. ADDRESS (City, State, and ZIP Code ) 7b. ADDRESS (City, State, and ZIP Code ...NOTATION 17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP DECISIONJ*MAKING...OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code ) 122c. OFFICE SYMBOL MAJ TIMOTHY D. LYNCH 9 684-3437 1 AT71-.qWV DO Form 1473, JUN 86

Ada Integrated Environment III Computer Program Development Specification. Volume III. Ada Optimizing Compiler.

DTIC Science & Technology

1981-12-01

file.library-unit{.subunit).SYMAP Statement Map: library-file. library-unit.subunit).SMAP Type Map: 1 ibrary.fi le. 1 ibrary-unit{.subunit). TMAP The library...generator SYMAP Symbol Map code generator SMAP Updated Statement Map code generator TMAP Type Map code generator A.3.5 The PUNIT Command The P UNIT...Core.Stmtmap) NAME Tmap (Core.Typemap) END Example A-3 Compiler Command Stream for the Code Generator Texas Instruments A-5 Ada Optimizing Compiler

The dilemma of the symbols: analogies between philosophy, biology and artificial life.

PubMed

Spadaro, Salvatore

2013-01-01

This article analyzes some analogies going from Artificial Life questions about the symbol-matter connection to Artificial Intelligence questions about symbol-grounding. It focuses on the notion of the interpretability of syntax and how the symbols are integrated in a unity ("binding problem"). Utilizing the DNA code as a model, this paper discusses how syntactic features could be defined as high-grade characteristics of the non syntactic relations in a material-dynamic structure, by using an emergentist approach. This topic furnishes the ground for a confutation of J. Searle's statement that syntax is observer-relative, as he wrote in his book "Mind: A Brief Introduction". Moreover the evolving discussion also modifies the classic symbol-processing doctrine in the mind which Searle attacks as a strong AL argument, that life could be implemented in a computational mode. Lastly, this paper furnishes a new way of support for the autonomous systems thesis in Artificial Life and Artificial Intelligence, using, inter alia, the "adaptive resonance theory" (ART).

Individual differences influence two-digit number processing, but not their analog magnitude processing: a large-scale online study.

PubMed

Huber, Stefan; Nuerk, Hans-Christoph; Reips, Ulf-Dietrich; Soltanlou, Mojtaba

2017-12-23

Symbolic magnitude comparison is one of the most well-studied cognitive processes in research on numerical cognition. However, while the cognitive mechanisms of symbolic magnitude processing have been intensively studied, previous studies have paid less attention to individual differences influencing symbolic magnitude comparison. Employing a two-digit number comparison task in an online setting, we replicated previous effects, including the distance effect, the unit-decade compatibility effect, and the effect of cognitive control on the adaptation to filler items, in a large-scale study in 452 adults. Additionally, we observed that the most influential individual differences were participants' first language, time spent playing computer games and gender, followed by reported alcohol consumption, age and mathematical ability. Participants who used a first language with a left-to-right reading/writing direction were faster than those who read and wrote in the right-to-left direction. Reported playing time for computer games was correlated with faster reaction times. Female participants showed slower reaction times and a larger unit-decade compatibility effect than male participants. Participants who reported never consuming alcohol showed overall slower response times than others. Older participants were slower, but more accurate. Finally, higher grades in mathematics were associated with faster reaction times. We conclude that typical experiments on numerical cognition that employ a keyboard as an input device can also be run in an online setting. Moreover, while individual differences have no influence on domain-specific magnitude processing-apart from age, which increases the decade distance effect-they generally influence performance on a two-digit number comparison task.

Testing a model of componential processing of multi-symbol numbers-evidence from measurement units.

PubMed

Huber, Stefan; Bahnmueller, Julia; Klein, Elise; Moeller, Korbinian

2015-10-01

Research on numerical cognition has addressed the processing of nonsymbolic quantities and symbolic digits extensively. However, magnitude processing of measurement units is still a neglected topic in numerical cognition research. Hence, we investigated the processing of measurement units to evaluate whether typical effects of multi-digit number processing such as the compatibility effect, the string length congruity effect, and the distance effect are also present for measurement units. In three experiments, participants had to single out the larger one of two physical quantities (e.g., lengths). In Experiment 1, the compatibility of number and measurement unit (compatible: 3 mm_6 cm with 3 < 6 and mm < cm; incompatible: 3 cm_6 mm with 3 < 6 but cm > mm) as well as string length congruity (congruent: 1 m_2 km with m < km and 2 < 3 characters; incongruent: 2 mm_1 m with mm < m, but 3 > 2 characters) were manipulated. We observed reliable compatibility effects with prolonged reaction times (RT) for incompatible trials. Moreover, a string length congruity effect was present in RT with longer RT for incongruent trials. Experiments 2 and 3 served as control experiments showing that compatibility effects persist when controlling for holistic distance and that a distance effect for measurement units exists. Our findings indicate that numbers and measurement units are processed in a componential manner and thus highlight that processing characteristics of multi-digit numbers generalize to measurement units. Thereby, our data lend further support to the recently proposed generalized model of componential multi-symbol number processing.

Clothing norms as markers of status in a hospital setting: A Bourdieusian analysis.

PubMed

Jenkins, Tania M

2014-09-01

This article uses a Bourdieusian framework to understand the importance of clothing norms for symbolizing and reproducing social, as well as professional, hierarchy in hospitals. Using data from participant observation, it examines how a complex yet informal dress code has emerged at a community hospital in the Northeastern United States, in a setting where very few formal guidelines exist on how to dress. By conceptualizing professionals as holders of various types of capital (economic, cultural, and symbolic), this article expands previous research which considered clothing only as a marker of professional identity. The findings demonstrate (1) how clothing norms are used in subtle, but purposeful, ways to reflect varying degrees of cultural and economic capital and (2) how these complex norms also reflect professional boundaries in medical authority (symbolic capital), which is important during critical moments where clothing can quickly signal who can take control. The discussion borrows Bourdieu's concepts of habitus and field to explain why subordinates subscribe to these clothing norms, in the absence of a formal organizational dress code. © The Author(s) 2014.

Manual versus automated coding of free-text self-reported medication data in the 45 and Up Study: a validation study.

PubMed

Gnjidic, Danijela; Pearson, Sallie-Anne; Hilmer, Sarah N; Basilakis, Jim; Schaffer, Andrea L; Blyth, Fiona M; Banks, Emily

2015-03-30

Increasingly, automated methods are being used to code free-text medication data, but evidence on the validity of these methods is limited. To examine the accuracy of automated coding of previously keyed in free-text medication data compared with manual coding of original handwritten free-text responses (the 'gold standard'). A random sample of 500 participants (475 with and 25 without medication data in the free-text box) enrolled in the 45 and Up Study was selected. Manual coding involved medication experts keying in free-text responses and coding using Anatomical Therapeutic Chemical (ATC) codes (i.e. chemical substance 7-digit level; chemical subgroup 5-digit; pharmacological subgroup 4-digit; therapeutic subgroup 3-digit). Using keyed-in free-text responses entered by non-experts, the automated approach coded entries using the Australian Medicines Terminology database and assigned corresponding ATC codes. Based on manual coding, 1377 free-text entries were recorded and, of these, 1282 medications were coded to ATCs manually. The sensitivity of automated coding compared with manual coding was 79% (n = 1014) for entries coded at the exact ATC level, and 81.6% (n = 1046), 83.0% (n = 1064) and 83.8% (n = 1074) at the 5, 4 and 3-digit ATC levels, respectively. The sensitivity of automated coding for blank responses was 100% compared with manual coding. Sensitivity of automated coding was highest for prescription medications and lowest for vitamins and supplements, compared with the manual approach. Positive predictive values for automated coding were above 95% for 34 of the 38 individual prescription medications examined. Automated coding for free-text prescription medication data shows very high to excellent sensitivity and positive predictive values, indicating that automated methods can potentially be useful for large-scale, medication-related research.

Moderate wine consumption is associated with better cognitive test results: a 7 year follow up of 5033 subjects in the Tromsø Study.

PubMed

Arntzen, K A; Schirmer, H; Wilsgaard, T; Mathiesen, E B

2010-01-01

The impact of moderate alcohol consumption on cognitive function and dementia is unclear. We examined the relationship between consumption of different alcoholic beverages and cognitive function in a large population-based study. Subjects were 5033 stroke-free men and women who participated in a longitudinal population-based study in Tromsø, Norway. Alcohol consumption and other cardiovascular risk factors were measured at baseline and cognitive function was assessed after 7 years follow up with verbal memory test, digit-symbol coding test and tapping test. Moderate wine consumption was independently associated with better performance on all cognitive tests in both men and women. There was no consistent association between consumption of beer and spirits and cognitive test results. Alcohol abstention was associated with lower cognitive performance in women. Light-to-moderate wine consumption was associated with better performance on cognitive tests after 7 years follow up.

Adaptive Spontaneous Transitions between Two Mechanisms of Numerical Averaging.

PubMed

Brezis, Noam; Bronfman, Zohar Z; Usher, Marius

2015-06-04

We investigated the mechanism with which humans estimate numerical averages. Participants were presented with 4, 8 or 16 (two-digit) numbers, serially and rapidly (2 numerals/second) and were instructed to convey the sequence average. As predicted by a dual, but not a single-component account, we found a non-monotonic influence of set-size on accuracy. Moreover, we observed a marked decrease in RT as set-size increases and RT-accuracy tradeoff in the 4-, but not in the 16-number condition. These results indicate that in accordance with the normative directive, participants spontaneously employ analytic/sequential thinking in the 4-number condition and intuitive/holistic thinking in the 16-number condition. When the presentation rate is extreme (10 items/sec) we find that, while performance still remains high, the estimations are now based on intuitive processing. The results are accounted for by a computational model postulating population-coding underlying intuitive-averaging and working-memory-mediated symbolic procedures underlying analytical-averaging, with flexible allocation between the two.

An integrated dexterous robotic testbed for space applications

NASA Technical Reports Server (NTRS)

Li, Larry C.; Nguyen, Hai; Sauer, Edward

1992-01-01

An integrated dexterous robotic system was developed as a testbed to evaluate various robotics technologies for advanced space applications. The system configuration consisted of a Utah/MIT Dexterous Hand, a PUMA 562 arm, a stereo vision system, and a multiprocessing computer control system. In addition to these major subsystems, a proximity sensing system was integrated with the Utah/MIT Hand to provide capability for non-contact sensing of a nearby object. A high-speed fiber-optic link was used to transmit digitized proximity sensor signals back to the multiprocessing control system. The hardware system was designed to satisfy the requirements for both teleoperated and autonomous operations. The software system was designed to exploit parallel processing capability, pursue functional modularity, incorporate artificial intelligence for robot control, allow high-level symbolic robot commands, maximize reusable code, minimize compilation requirements, and provide an interactive application development and debugging environment for the end users. An overview is presented of the system hardware and software configurations, and implementation is discussed of subsystem functions.

Concatenated coding systems employing a unit-memory convolutional code and a byte-oriented decoding algorithm

NASA Technical Reports Server (NTRS)

Lee, L.-N.

1977-01-01

Concatenated coding systems utilizing a convolutional code as the inner code and a Reed-Solomon code as the outer code are considered. In order to obtain very reliable communications over a very noisy channel with relatively modest coding complexity, it is proposed to concatenate a byte-oriented unit-memory convolutional code with an RS outer code whose symbol size is one byte. It is further proposed to utilize a real-time minimal-byte-error probability decoding algorithm, together with feedback from the outer decoder, in the decoder for the inner convolutional code. The performance of the proposed concatenated coding system is studied, and the improvement over conventional concatenated systems due to each additional feature is isolated.

Concatenated coding systems employing a unit-memory convolutional code and a byte-oriented decoding algorithm

NASA Technical Reports Server (NTRS)

Lee, L. N.

1976-01-01

Concatenated coding systems utilizing a convolutional code as the inner code and a Reed-Solomon code as the outer code are considered. In order to obtain very reliable communications over a very noisy channel with relatively small coding complexity, it is proposed to concatenate a byte oriented unit memory convolutional code with an RS outer code whose symbol size is one byte. It is further proposed to utilize a real time minimal byte error probability decoding algorithm, together with feedback from the outer decoder, in the decoder for the inner convolutional code. The performance of the proposed concatenated coding system is studied, and the improvement over conventional concatenated systems due to each additional feature is isolated.

Convolution Operations on Coding Metasurface to Reach Flexible and Continuous Controls of Terahertz Beams.

PubMed

Liu, Shuo; Cui, Tie Jun; Zhang, Lei; Xu, Quan; Wang, Qiu; Wan, Xiang; Gu, Jian Qiang; Tang, Wen Xuan; Qing Qi, Mei; Han, Jia Guang; Zhang, Wei Li; Zhou, Xiao Yang; Cheng, Qiang

2016-10-01

The concept of coding metasurface makes a link between physically metamaterial particles and digital codes, and hence it is possible to perform digital signal processing on the coding metasurface to realize unusual physical phenomena. Here, this study presents to perform Fourier operations on coding metasurfaces and proposes a principle called as scattering-pattern shift using the convolution theorem, which allows steering of the scattering pattern to an arbitrarily predesigned direction. Owing to the constant reflection amplitude of coding particles, the required coding pattern can be simply achieved by the modulus of two coding matrices. This study demonstrates that the scattering patterns that are directly calculated from the coding pattern using the Fourier transform have excellent agreements to the numerical simulations based on realistic coding structures, providing an efficient method in optimizing coding patterns to achieve predesigned scattering beams. The most important advantage of this approach over the previous schemes in producing anomalous single-beam scattering is its flexible and continuous controls to arbitrary directions. This work opens a new route to study metamaterial from a fully digital perspective, predicting the possibility of combining conventional theorems in digital signal processing with the coding metasurface to realize more powerful manipulations of electromagnetic waves.

An Economical Multifactor within-Subject Design Robust against Trend and Carryover Effects.

DTIC Science & Technology

1985-10-17

ORGANIZATION REPORT NUMBER (S) S. MONIT ,,M.,,...---. 6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION Essex...Road Orlando, FL 32813 Orlando, FL 32803 Ba. NAME OF FUNDING/SPONSORING " Sb. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ...ORGANIZATION (If applicable) S6~1332- &/. 0.-/195𔃺 Sc. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT

Partial correlation properties of pseudonoise /PN/ codes in noncoherent synchronization/detection schemes

NASA Technical Reports Server (NTRS)

Cartier, D. E.

1976-01-01

This concise paper considers the effect on the autocorrelation function of a pseudonoise (PN) code when the acquisition scheme only integrates coherently over part of the code and then noncoherently combines these results. The peak-to-null ratio of the effective PN autocorrelation function is shown to degrade to the square root of n, where n is the number of PN symbols over which coherent integration takes place.

Communication systems, transceivers, and methods for generating data based on channel characteristics

DOEpatents

Forman, Michael A; Young, Derek

2012-09-18

Examples of methods for generating data based on a communications channel are described. In one such example, a processing unit may generate a first vector representation based in part on at least two characteristics of a communications channel. A constellation having at least two dimensions may be addressed with the first vector representation to identify a first symbol associated with the first vector representation. The constellation represents a plurality of regions, each region associated with a respective symbol. The symbol may be used to generate data, which may stored in an electronic storage medium and used as a cryptographic key or a spreading code or hopping sequence in a modulation technique.

Higher order spectra and their use in digital communication signal estimation

NASA Astrophysics Data System (ADS)

Yayci, Cihat

1995-03-01

This thesis compared the detection ability of the spectrogram, the 1-1/2D instantaneous power spectrum (l-1/2D(sub ips)), the bispectrum, and outer product (dyadic) representation for digitally modulated signals corrupted by additive white Gaussian noise. Four detection schemes were tried on noise free BPSK, QPSK, FSK, and OOK signals using different transform lengths. After determining the optimum transform length, each test signal is corrupted by additive white Gaussian noise. Different SNR levels were used to determine the lowest SNR level at which the message or the modulation type could be extracted. The optimal transform length was found to be the symbol duration when processing BPSK, OOK, and FSK via the spectrogram, the 1-1/2D(sub ips) or the bispectrum method. The best transform size for QPSK was half of the symbol length. For the outer product (dyadic) spectral representation, the best transform size was four times larger than the symbol length. For all processing techniques, with the exception of the other product representation, the minimum detectable SNR is about 15 dB for BPSK, FSK, and OOK signals and about 20 dB for QPSK signals. For the outer product spectral method, these values tend to be about 10 dB lower.

Real-time transmission of digital video using variable-length coding

NASA Technical Reports Server (NTRS)

Bizon, Thomas P.; Shalkhauser, Mary JO; Whyte, Wayne A., Jr.

1993-01-01

Huffman coding is a variable-length lossless compression technique where data with a high probability of occurrence is represented with short codewords, while 'not-so-likely' data is assigned longer codewords. Compression is achieved when the high-probability levels occur so frequently that their benefit outweighs any penalty paid when a less likely input occurs. One instance where Huffman coding is extremely effective occurs when data is highly predictable and differential coding can be applied (as with a digital video signal). For that reason, it is desirable to apply this compression technique to digital video transmission; however, special care must be taken in order to implement a communication protocol utilizing Huffman coding. This paper addresses several of the issues relating to the real-time transmission of Huffman-coded digital video over a constant-rate serial channel. Topics discussed include data rate conversion (from variable to a fixed rate), efficient data buffering, channel coding, recovery from communication errors, decoder synchronization, and decoder architectures. A description of the hardware developed to execute Huffman coding and serial transmission is also included. Although this paper focuses on matters relating to Huffman-coded digital video, the techniques discussed can easily be generalized for a variety of applications which require transmission of variable-length data.

Symbolic Play and Novel Noun Learning in Deaf and Hearing Children: Longitudinal Effects of Access to Sound on Early Precursors of Language.

PubMed

Quittner, Alexandra L; Cejas, Ivette; Wang, Nae-Yuh; Niparko, John K; Barker, David H

2016-01-01

In the largest, longitudinal study of young, deaf children before and three years after cochlear implantation, we compared symbolic play and novel noun learning to age-matched hearing peers. Participants were 180 children from six cochlear implant centers and 96 hearing children. Symbolic play was measured during five minutes of videotaped, structured solitary play. Play was coded as "symbolic" if the child used substitution (e.g., a wooden block as a bed). Novel noun learning was measured in 10 trials using a novel object and a distractor. Cochlear implant vs. normal hearing children were delayed in their use of symbolic play, however, those implanted before vs. after age two performed significantly better. Children with cochlear implants were also delayed in novel noun learning (median delay 1.54 years), with minimal evidence of catch-up growth. Quality of parent-child interactions was positively related to performance on the novel noun learning, but not symbolic play task. Early implantation was beneficial for both achievement of symbolic play and novel noun learning. Further, maternal sensitivity and linguistic stimulation by parents positively affected noun learning skills, although children with cochlear implants still lagged in comparison to hearing peers.

Symbolic Play and Novel Noun Learning in Deaf and Hearing Children: Longitudinal Effects of Access to Sound on Early Precursors of Language

PubMed Central

Quittner, Alexandra L.; Cejas, Ivette; Wang, Nae-Yuh; Niparko, John K.; Barker, David H.

2016-01-01

In the largest, longitudinal study of young, deaf children before and three years after cochlear implantation, we compared symbolic play and novel noun learning to age-matched hearing peers. Participants were 180 children from six cochlear implant centers and 96 hearing children. Symbolic play was measured during five minutes of videotaped, structured solitary play. Play was coded as "symbolic" if the child used substitution (e.g., a wooden block as a bed). Novel noun learning was measured in 10 trials using a novel object and a distractor. Cochlear implant vs. normal hearing children were delayed in their use of symbolic play, however, those implanted before vs. after age two performed significantly better. Children with cochlear implants were also delayed in novel noun learning (median delay 1.54 years), with minimal evidence of catch-up growth. Quality of parent-child interactions was positively related to performance on the novel noun learning, but not symbolic play task. Early implantation was beneficial for both achievement of symbolic play and novel noun learning. Further, maternal sensitivity and linguistic stimulation by parents positively affected noun learning skills, although children with cochlear implants still lagged in comparison to hearing peers. PMID:27228032

Northwest plant names and symbols for ecosystem inventory and analysis.

Treesearch

G.A. Garrison; J.M. Skovlin; C.E. Poulton; A.H. Winward

1976-01-01

This paper is basically an alpha code and name listing of forest and rangeland grasses, sedges, rushes, forbs, shrubs, and trees of Oregon, Washington, and Idaho. The code expedites recording of vegetation inventory data and is especially useful to those processing their data by contemporary computer systems. Editorial and secretarial personnel will find the name and...

Distributed single source coding with side information

NASA Astrophysics Data System (ADS)

Vila-Forcen, Jose E.; Koval, Oleksiy; Voloshynovskiy, Sviatoslav V.

2004-01-01

In the paper we advocate image compression technique in the scope of distributed source coding framework. The novelty of the proposed approach is twofold: classical image compression is considered from the positions of source coding with side information and, contrarily to the existing scenarios, where side information is given explicitly, side information is created based on deterministic approximation of local image features. We consider an image in the transform domain as a realization of a source with a bounded codebook of symbols where each symbol represents a particular edge shape. The codebook is image independent and plays the role of auxiliary source. Due to the partial availability of side information at both encoder and decoder we treat our problem as a modification of Berger-Flynn-Gray problem and investigate a possible gain over the solutions when side information is either unavailable or available only at decoder. Finally, we present a practical compression algorithm for passport photo images based on our concept that demonstrates the superior performance in very low bit rate regime.

Artistic production in dyslectic children.

PubMed

Cohn, R; Neumann, M A

1977-01-01

In the study of children with language problems, particularly in reading and writing, it has been observed that some have an outstanding ability to produce artistic pictures and objects. These productions are perceptive, well organized and generally contain much action. Despite their pictorial skill these patients may have only a rudimentary use of coded symbolic graphic forms. Others display moderate ability in reading and writing. These patients frequently have the disorganized overacctive behavior and the motor clumsiness that is so common in the dyslectic child; some, however, are biologically effective. From this material we entertain the hypothesis that picture (artistic) productions are generated by the sub-dominant cerebral hemisphere, and that this function is quite distinct from the coded graphic operations resident in the dominant hemisphere. If this hypothesis is correct, it would seem socially benefical to allow these patients to develop their unique artistic ability to its full capacity, and not to overemphasize the correction of the disturbed coded symbol operations in remedial training.

A TDM link with channel coding and digital voice.

NASA Technical Reports Server (NTRS)

Jones, M. W.; Tu, K.; Harton, P. L.

1972-01-01

The features of a TDM (time-division multiplexed) link model are described. A PCM telemetry sequence was coded for error correction and multiplexed with a digitized voice channel. An all-digital implementation of a variable-slope delta modulation algorithm was used to digitize the voice channel. The results of extensive testing are reported. The measured coding gain and the system performance over a Gaussian channel are compared with theoretical predictions and computer simulations. Word intelligibility scores are reported as a measure of voice channel performance.

Pictorial Superiority Effect

ERIC Educational Resources Information Center

Nelson, Douglas L.; And Others

1976-01-01

Pictures generally show superior recognition relative to their verbal labels. This experiment was designed to link this pictorial superiority effect to sensory or meaning codes associated with the two types of symbols. (Editor)

Performance of concatenated Reed-Solomon trellis-coded modulation over Rician fading channels

NASA Technical Reports Server (NTRS)

Moher, Michael L.; Lodge, John H.

1990-01-01

A concatenated coding scheme for providing very reliable data over mobile-satellite channels at power levels similar to those used for vocoded speech is described. The outer code is a shorter Reed-Solomon code which provides error detection as well as error correction capabilities. The inner code is a 1-D 8-state trellis code applied independently to both the inphase and quadrature channels. To achieve the full error correction potential of this inner code, the code symbols are multiplexed with a pilot sequence which is used to provide dynamic channel estimation and coherent detection. The implementation structure of this scheme is discussed and its performance is estimated.

Learning representation hierarchies by sharing visual features: a computational investigation of Persian character recognition with unsupervised deep learning.

PubMed

Sadeghi, Zahra; Testolin, Alberto

2017-08-01

In humans, efficient recognition of written symbols is thought to rely on a hierarchical processing system, where simple features are progressively combined into more abstract, high-level representations. Here, we present a computational model of Persian character recognition based on deep belief networks, where increasingly more complex visual features emerge in a completely unsupervised manner by fitting a hierarchical generative model to the sensory data. Crucially, high-level internal representations emerging from unsupervised deep learning can be easily read out by a linear classifier, achieving state-of-the-art recognition accuracy. Furthermore, we tested the hypothesis that handwritten digits and letters share many common visual features: A generative model that captures the statistical structure of the letters distribution should therefore also support the recognition of written digits. To this aim, deep networks trained on Persian letters were used to build high-level representations of Persian digits, which were indeed read out with high accuracy. Our simulations show that complex visual features, such as those mediating the identification of Persian symbols, can emerge from unsupervised learning in multilayered neural networks and can support knowledge transfer across related domains.

Closure measures for coarse-graining of the tent map.

PubMed

Pfante, Oliver; Olbrich, Eckehard; Bertschinger, Nils; Ay, Nihat; Jost, Jürgen

2014-03-01

We quantify the relationship between the dynamics of a time-discrete dynamical system, the tent map T and its iterations T(m), and the induced dynamics at a symbolical level in information theoretical terms. The symbol dynamics, given by a binary string s of length m, is obtained by choosing a partition point [Formula: see text] and lumping together the points [Formula: see text] s.t. T(i)(x) concurs with the i - 1th digit of s-i.e., we apply a so called threshold crossing technique. Interpreting the original dynamics and the symbolic one as different levels, this allows us to quantitatively evaluate and compare various closure measures that have been proposed for identifying emergent macro-levels of a dynamical system. In particular, we can see how these measures depend on the choice of the partition point α. As main benefit of this new information theoretical approach, we get all Markov partitions with full support of the time-discrete dynamical system induced by the tent map. Furthermore, we could derive an example of a Markovian symbol dynamics whose underlying partition is not Markovian at all, and even a whole hierarchy of Markovian symbol dynamics.

Semantic and perceptual processing of number symbols: evidence from a cross-linguistic fMRI adaptation study.

PubMed

Holloway, Ian D; Battista, Christian; Vogel, Stephan E; Ansari, Daniel

2013-03-01

The ability to process the numerical magnitude of sets of items has been characterized in many animal species. Neuroimaging data have associated this ability to represent nonsymbolic numerical magnitudes (e.g., arrays of dots) with activity in the bilateral parietal lobes. Yet the quantitative abilities of humans are not limited to processing the numerical magnitude of nonsymbolic sets. Humans have used this quantitative sense as the foundation for symbolic systems for the representation of numerical magnitude. Although numerical symbol use is widespread in human cultures, the brain regions involved in processing of numerical symbols are just beginning to be understood. Here, we investigated the brain regions underlying the semantic and perceptual processing of numerical symbols. Specifically, we used an fMRI adaptation paradigm to examine the neural response to Hindu-Arabic numerals and Chinese numerical ideographs in a group of Chinese readers who could read both symbol types and a control group who could read only the numerals. Across groups, the Hindu-Arabic numerals exhibited ratio-dependent modulation in the left IPS. In contrast, numerical ideographs were associated with activation in the right IPS, exclusively in the Chinese readers. Furthermore, processing of the visual similarity of both digits and ideographs was associated with activation of the left fusiform gyrus. Using culture as an independent variable, we provide clear evidence for differences in the brain regions associated with the semantic and perceptual processing of numerical symbols. Additionally, we reveal a striking difference in the laterality of parietal activation between the semantic processing of the two symbols types.

INSPECTION MEANS FOR INDUCTION MOTORS

DOEpatents

Williams, A.W.

1959-03-10

an appartus is descripbe for inspcting electric motors and more expecially an appartus for detecting falty end rings inn suqirrel cage inductio motors while the motor is running. In its broua aspects, the mer would around ce of reference tedtor means also itons in the phase ition of the An electronic circuit for conversion of excess-3 binary coded serial decimal numbers to straight binary coded serial decimal numbers is reported. The converter of the invention in its basic form generally coded pulse words of a type having an algebraic sign digit followed serially by a plurality of decimal digits in order of decreasing significance preceding a y algebraic sign digit followed serially by a plurality of decimal digits in order of decreasing significance. A switching martix is coupled to said input circuit and is internally connected to produce serial straight binary coded pulse groups indicative of the excess-3 coded input. A stepping circuit is coupled to the switching matrix and to a synchronous counter having a plurality of x decimal digit and plurality of y decimal digit indicator terminals. The stepping circuit steps the counter in synchornism with the serial binary pulse group output from the switching matrix to successively produce pulses at corresponding ones of the x and y decimal digit indicator terminals. The combinations of straight binary coded pulse groups and corresponding decimal digit indicator signals so produced comprise a basic output suitable for application to a variety of output apparatus.

Digitized forensics: retaining a link between physical and digital crime scene traces using QR-codes

NASA Astrophysics Data System (ADS)

Hildebrandt, Mario; Kiltz, Stefan; Dittmann, Jana

2013-03-01

The digitization of physical traces from crime scenes in forensic investigations in effect creates a digital chain-of-custody and entrains the challenge of creating a link between the two or more representations of the same trace. In order to be forensically sound, especially the two security aspects of integrity and authenticity need to be maintained at all times. Especially the adherence to the authenticity using technical means proves to be a challenge at the boundary between the physical object and its digital representations. In this article we propose a new method of linking physical objects with its digital counterparts using two-dimensional bar codes and additional meta-data accompanying the acquired data for integration in the conventional documentation of collection of items of evidence (bagging and tagging process). Using the exemplary chosen QR-code as particular implementation of a bar code and a model of the forensic process, we also supply a means to integrate our suggested approach into forensically sound proceedings as described by Holder et al.1 We use the example of the digital dactyloscopy as a forensic discipline, where currently progress is being made by digitizing some of the processing steps. We show an exemplary demonstrator of the suggested approach using a smartphone as a mobile device for the verification of the physical trace to extend the chain-of-custody from the physical to the digital domain. Our evaluation of the demonstrator is performed towards the readability and the verification of its contents. We can read the bar code despite its limited size of 42 x 42 mm and rather large amount of embedded data using various devices. Furthermore, the QR-code's error correction features help to recover contents of damaged codes. Subsequently, our appended digital signature allows for detecting malicious manipulations of the embedded data.

Coding for Single-Line Transmission

NASA Technical Reports Server (NTRS)

Madison, L. G.

1983-01-01

Digital transmission code combines data and clock signals into single waveform. MADCODE needs four standard integrated circuits in generator and converter plus five small discrete components. MADCODE allows simple coding and decoding for transmission of digital signals over single line.

Assessment of the knowledge of graphical symbols labelled on malaria rapid diagnostic tests in four international settings

PubMed Central

2011-01-01

Background Graphical symbols on in vitro diagnostics (IVD symbols) replace the need for text in different languages and are used on malaria rapid diagnostic tests (RDTs) marketed worldwide. The present study assessed the comprehension of IVD symbols labelled on malaria RDT kits among laboratory staff in four different countries. Methods Participants (n = 293) in Belgium (n = 96), the Democratic Republic of the Congo (DRC, n = 87), Cambodia (n = 59) and Cuba (n = 51) were presented with an anonymous questionnaire with IVD symbols extracted from ISO 15223 and EN 980 presented as stand-alone symbols (n = 18) and in context (affixed on RDT packages, n = 16). Responses were open-ended and scored for correctness by local professionals. Results Presented as stand-alone, three and five IVD symbols were correctly scored for comprehension by 67% and 50% of participants; when contextually presented, five and seven symbols reached the 67% and 50% correct score respectively. 'Batch code' scored best (correctly scored by 71.3% of participants when presented as stand-alone), 'Authorized representative in the European Community' scored worst (1.4% correct). Another six IVD symbols were scored correctly by less than 10% of participants: 'Do not reuse', 'In vitro diagnostic medical device', 'Sufficient for', 'Date of manufacture', 'Authorised representative in EC', and 'Do not use if package is damaged'. Participants in Belgium and Cuba both scored six symbols above the 67% criterion, participants from DRC and Cambodia scored only two and one symbols above this criterion. Low correct scores were observed for safety-related IVD symbols, such as for 'Biological Risk' (42.7%) and 'Do not reuse' (10.9%). Conclusion Comprehension of IVD symbols on RDTs among laboratory staff in four international settings was unsatisfactory. Administrative and outreach procedures should be undertaken to assure their acquaintance by end-users. PMID:22047089

Efficient hybrid-symbolic methods for quantum mechanical calculations

NASA Astrophysics Data System (ADS)

Scott, T. C.; Zhang, Wenxing

2015-06-01

We present hybrid symbolic-numerical tools to generate optimized numerical code for rapid prototyping and fast numerical computation starting from a computer algebra system (CAS) and tailored to any given quantum mechanical problem. Although a major focus concerns the quantum chemistry methods of H. Nakatsuji which has yielded successful and very accurate eigensolutions for small atoms and molecules, the tools are general and may be applied to any basis set calculation with a variational principle applied to its linear and non-linear parameters.

An Assessment of Potential Soviet Responses to Evolving Theater Nuclear Systems.

DTIC Science & Technology

1987-06-05

ORGANIZATION REPORT NUMIBER(S) 5 MONITORING ORGANIZAODN REPORT NUMNBER(S) 6a NAM OFPERFORMING ORGANIZATION fib OFFICE SYMBOL 7& NAME OF MONITORING... ORGANIZATION 6C. ADDRESS (Oty. State, and ZIP Cod.) 7b ADDRESSC,ty, State, and ZIP Cod.) Vicksburg, MS 39180-0631 Ba AMEOF UNDNG SPOSORNG8b OFFICE SYMBOL...9 PROCuREMENT INSR~UMENT IDENTiCICATtON N%BER ORGANIZATION (If appliabe USAm op fEgnes DN’o~)1 Bk. ADDRESS (City, State, and ZIP Code) 10 SOURCE OF

Massive Symbolic Mathematical Computations and Their Applications

DTIC Science & Technology

1988-08-16

NUMBER ORGANIZATION (if appi cable) AFOSR I A_ /__ I F49620-87- C -0113 Bc. ADDRESS (City, Stare, and ZIP Code) %. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT...TASK WORK UNIT - < ’/I/ "//ELEMENT NO. NO. NO. ACCESSION NO. /,, AF,; c 9r ;- 6 (4/tL’ " ’ ’! /K’, 11 TITLE (Incoue Secuirty Classification) Massive...DARPA R & D Status Report AFOSR.m. 8 8-1 12Contract No. F49620-87- C -0113 MASSIVE SYMBOLIC MATHEMATICAL COMPUTATIONS AND THEIR APPLICATIONS Quarterly

All Prime Contract Awards by State or Country, Place, and Contractor, FY 87. Part 2. Agoura Hills, California-Lafayette, California.

DTIC Science & Technology

1987-01-01

OWNGRADING SCHEDULE Approved for public release 4. PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) DIOR/ST11-87...Pr- 2 6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION WHS, Directorate for (if applicable) nformation...SPONSORING 1Sb. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (if applicable) Sc. ADDRESS (City, State, and ZIP Code) 10. SOURCE

Performance Analysis of a JTIDS/Link-16 Type Waveform using 32-ary Orthogonal Signaling with 32 Chip Baseband Waveforms and a Concatenated Code

DTIC Science & Technology

2009-12-01

with 32 chip baseband waveforms such as Walsh functions. Performance with both coherent and noncoherent detection is analyzed. For noncoherent ...detection, only one five bit symbol is transmitted on the I and Q components of the carrier per symbol duration, so the data throughput for noncoherent ...for coherent and noncoherent demodulation, respectively, when 510bP  . Likewise, in an AWGN only environment with a diversity of two, the proposed

Trellis Coding of Non-coherent Multiple Symbol Full Response M-ary CPFSK with Modulation Index 1/M

NASA Technical Reports Server (NTRS)

Lee, H.; Divsalar, D.; Weber, C.

1994-01-01

This paper introduces a trellis coded modulation (TCM) scheme for non-coherent multiple full response M-ary CPFSK with modulation index 1/M. A proper branch metric for the trellis decoder is obtained by employing a simple approximation of the modified Bessel function for large signal to noise ratio (SNR). Pairwise error probability of coded sequences is evaluated by applying a linear approximation to the Rician random variable.

European Science Notes. Volume 40, Number 4.

DTIC Science & Technology

1986-04-01

OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (if applicable) 8c. ADDRESS (City, State, and ZIP Code ) 10. SOURCE OF...Office, London ONRL 6c. ADDRESS (City, State, and ZIP Code ) 7b. ADDRESS (City, State, and ZIPCode) Box 39 FPO, NY 09510 Ba. NAME OF FUNDING/SPONSORING 8b...13..TYPj9 REPORT13bTIECVRD1.DTOFRPT(YaMnhDy)1.AGCUNMonthly FROM TO _ April 1986 32 16. SUPPLEMENTARY NOTATION 17. COSATI CODES 18. SUBJECT TERMS

Verifying the Chemical Weapons Convention: The Case for a United Nations Verification Agency

DTIC Science & Technology

1991-12-01

ORGANIZATION REPORT NUMBER(S) 6&. NAME OF PERFORMING ORGANIZATION j6b. OFFICE SYMBOL 7&. NAME OF MONITORING ORGANIZATION Naval Postgraduate School J(if applicaip...Naval Postgraduate School 6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code) Monterey. CA 93943-5000 Monterey, CA 93943...Governinent. 17. COSATI CODES 18. SUBJECT TERMS (continue on reverse if necessaty and identify by black number) -FIELD GROUP SUBGROUP Chemical

Health claims in the labelling and marketing of food products:

PubMed Central

Asp, Nils-Georg; Bryngelsson, Susanne

2007-01-01

Since 1990 certain health claims in the labelling and marketing of food products have been allowed in Sweden within the food sector's Code of Practice. The rules were developed in close dialogue with the authorities. The legal basis was a decision by the authorities not to apply the medicinal products’ legislation to “foods normally found on the dinner table” provided the rules defined in the Code were followed. The Code of Practice lists nine well-established diet–health relationships eligible for generic disease risk reduction claims in two steps and general rules regarding nutrient function claims. Since 2001, there has also been the possibility for using “product-specific physiological claims (PFP)”, subject to premarketing evaluation of the scientific dossier supporting the claim. The scientific documentation has been approved for 10 products with PFP, and another 15 products have been found to fulfil the Code's criteria for “low glycaemic index”. In the third edition of the Code, active since 2004, conditions in terms of nutritional composition were set, i.e. “nutrient profiles”, with a general reference to the Swedish National Food Administration's regulation on the use of a particular symbol, i.e. the keyhole symbol. Applying the Swedish Code of practice has provided experience useful in the implementation of the European Regulation on nutrition and health claims made on foods, effective from 2007.

Digital barcodes of suspension array using laser induced breakdown spectroscopy

PubMed Central

He, Qinghua; Liu, Yixi; He, Yonghong; Zhu, Liang; Zhang, Yilong; Shen, Zhiyuan

2016-01-01

We show a coding method of suspension array based on the laser induced breakdown spectroscopy (LIBS), which promotes the barcodes from analog to digital. As the foundation of digital optical barcodes, nanocrystals encoded microspheres are prepared with self-assembly encapsulation method. We confirm that digital multiplexing of LIBS-based coding method becomes feasible since the microsphere can be coded with direct read-out data of wavelengths, and the method can avoid fluorescence signal crosstalk between barcodes and analyte tags, which lead to overall advantages in accuracy and stability to current fluorescent multicolor coding method. This demonstration increases the capability of multiplexed detection and accurate filtrating, expanding more extensive applications of suspension array in life science. PMID:27808270

With a little help from my spouse: does spousal collaboration compensate for the effects of cognitive aging?

PubMed

Rauers, Antje; Riediger, Michaela; Schmiedek, Florian; Lindenberger, Ulman

2011-01-01

Collaborating with another person may help people compensate for aging-related losses in memory performance. However, collaborating in itself is effortful and draws upon individual cognitive resources. One factor that can facilitate collaboration, and decrease its resource requirements, is familiarity between interaction partners. Such facilitation should be particularly important when cognitive-mechanic resources are low. The current study was conducted to empirically test this theoretical notion. We hypothesized that cognitive aging should amplify the advantage of collaborating with a familiar partner over collaborating with an unfamiliar person. We developed an interpersonal cueing task based on the game Taboo©. The task modeled an everyday-life situation in which one person cues another person to retrieve a piece of information from memory. Seventy-six younger adults (20-33 years) and 80 older adults (63-79 years) worked on this task once with their spouse and once with an unfamiliar cross-sex partner from the same age group. Collaborative performance was operationalized as the number of cue words needed until the partner guessed the target, as determined by independent trained coders. Performance in the Digit Symbol Substitution Test was used as an indicator of cognitive aging. Multilevel-modeling analyses revealed that collaborating spouses outperformed collaborators who had not known each other before. This effect was comparable for both age groups but larger in persons with lower Digit Symbol scores. While participants with lower Digit Symbol scores generally performed worse in the collaborative task, they partly made up for this difference when working with the spouse. We conclude that spousal collaboration may offer a compensatory strategy to cope with individual aging-related losses. Copyright © 2010 S. Karger AG, Basel.

Research on coding and decoding method for digital levels.

PubMed

Tu, Li-fen; Zhong, Si-dong

2011-01-20

A new coding and decoding method for digital levels is proposed. It is based on an area-array CCD sensor and adopts mixed coding technology. By taking advantage of redundant information in a digital image signal, the contradiction that the field of view and image resolution restrict each other in a digital level measurement is overcome, and the geodetic leveling becomes easier. The experimental results demonstrate that the uncertainty of measurement is 1 mm when the measuring range is between 2 m and 100 m, which can meet practical needs.

Robust Self-Authenticating Network Coding

DTIC Science & Technology

2008-11-30

efficient as traditional point-to-point coding schemes 3m*b*c*ts»tt a«2b»c*dt4g »4.0»C* 3d *Sh Number of symbols that an intermediate node has to...Institute of Technology This work was partly supported by the Fundacao para a Ciencia e Tecnologia (Portuguese foundation lor Science and Technology

The Design and Implementation of a Read Prediction Buffer

DTIC Science & Technology

1992-12-01

City, State, and ZIP Code) 7b ADDRESS (City, State. and ZIP Code) 8a. NAME OF FUNDING /SPONSORING 8b. OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT... 9 E. THESIS STRUCTURE.. . .... ............... 9 II. READ PREDICTION ALGORITHM AND BUFFER DESIGN 10 A. THE READ PREDICTION ALGORITHM...29 Figure 9 . Basic Multiplexer Cell .... .......... .. 30 Figure 10. Block Diagram Simulation Labels ......... 38 viii I. INTRODUCTION A

47 CFR 52.7 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Administration § 52.7 Definitions. As used in this subpart: (a) Area code or numbering plan area (NPA). The term “area code or numbering plan area” refers to the first three digits (NXX) of a ten-digit telephone... “central office code” refers to the second three digits (NXX) of a ten-digit telephone number in the form...

47 CFR 52.7 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Administration § 52.7 Definitions. As used in this subpart: (a) Area code or numbering plan area (NPA). The term “area code or numbering plan area” refers to the first three digits (NXX) of a ten-digit telephone... “central office code” refers to the second three digits (NXX) of a ten-digit telephone number in the form...

47 CFR 52.7 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Administration § 52.7 Definitions. As used in this subpart: (a) Area code or numbering plan area (NPA). The term “area code or numbering plan area” refers to the first three digits (NXX) of a ten-digit telephone... “central office code” refers to the second three digits (NXX) of a ten-digit telephone number in the form...

47 CFR 52.7 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Administration § 52.7 Definitions. As used in this subpart: (a) Area code or numbering plan area (NPA). The term “area code or numbering plan area” refers to the first three digits (NXX) of a ten-digit telephone... “central office code” refers to the second three digits (NXX) of a ten-digit telephone number in the form...

Symbolic Execution Enhanced System Testing

NASA Technical Reports Server (NTRS)

Davies, Misty D.; Pasareanu, Corina S.; Raman, Vishwanath

2012-01-01

We describe a testing technique that uses information computed by symbolic execution of a program unit to guide the generation of inputs to the system containing the unit, in such a way that the unit's, and hence the system's, coverage is increased. The symbolic execution computes unit constraints at run-time, along program paths obtained by system simulations. We use machine learning techniques treatment learning and function fitting to approximate the system input constraints that will lead to the satisfaction of the unit constraints. Execution of system input predictions either uncovers new code regions in the unit under analysis or provides information that can be used to improve the approximation. We have implemented the technique and we have demonstrated its effectiveness on several examples, including one from the aerospace domain.

Digitization of a geologic map for the Quebec-Maine-Gulf of Maine global geoscience transect

USGS Publications Warehouse

Wright, Bruce E.; Stewart, David B.

1990-01-01

The Bedrock Geologic Map of Maine was digitized and combined with digital geologic data for Quebec and the Gulf of Maine for the Quebec-Maine-Gulf of Maine Geologic Transect Project. This map is being combined with digital geophysical data to produce three-dimensional depictions of the subsurface geology and to produce cross sections of the Earth's crust. It is an essential component of a transect that stretches from the craton near Quebec City, Quebec, to the Atlantic Ocean Basin south of Georges Bank. The transect is part of the Global Geosciences Transect Project of the International Lithosphere Program. The Digital Line Graph format is used for storage of the digitized data. A coding scheme similar to that used for base category planimetric data was developed to assign numeric codes to the digitized geologic data. These codes were used to assign attributes to polygon and line features to describe rock type, age, name, tectonic setting of original deposition, mineralogy, and composition of igneous plutonic rocks, as well as faults and other linear features. The digital geologic data can be readily edited, rescaled, and reprojected. The attribute codes allow generalization and selective retrieval of the geologic features. The codes allow assignment of map colors based on age, lithology, or other attribute. The Digital Line Graph format is a general transfer format that is supported by many software vendors and is easily transferred between systems.

Regression-based pediatric norms for the brief visuospatial memory test: revised and the symbol digit modalities test.

PubMed

Smerbeck, A M; Parrish, J; Yeh, E A; Hoogs, M; Krupp, Lauren B; Weinstock-Guttman, B; Benedict, R H B

2011-04-01

The Brief Visuospatial Memory Test - Revised (BVMTR) and the Symbol Digit Modalities Test (SDMT) oral-only administration are known to be sensitive to cerebral disease in adult samples, but pediatric norms are not available. A demographically balanced sample of healthy control children (N = 92) ages 6-17 was tested with the BVMTR and SDMT. Multiple regression analysis (MRA) was used to develop demographically controlled normative equations. This analysis provided equations that were then used to construct demographically adjusted z-scores for the BVMTR Trial 1, Trial 2, Trial 3, Total Learning, and Delayed Recall indices, as well as the SDMT total correct score. To demonstrate the utility of this approach, a comparison group of children with acute disseminated encephalomyelitis (ADEM) or multiple sclerosis (MS) were also assessed. We find that these visual processing tests discriminate neurological patients from controls. As the tests are validated in adult multiple sclerosis, they are likely to be useful in monitoring pediatric onset multiple sclerosis patients as they transition into adulthood.

Direct bit detection receiver noise performance analysis for 32-PSK and 64-PSK modulated signals

NASA Astrophysics Data System (ADS)

Ahmed, Iftikhar

1987-12-01

Simple two channel receivers for 32-PSK and 64-PSK modulated signals have been proposed which allow digital data (namely bits), to be recovered directly instead of the traditional approach of symbol detection followed by symbol to bit mappings. This allows for binary rather than M-ary receiver decisions, reduces the amount of signal processing operations and permits parallel recovery of the bits. The noise performance of these receivers quantified by the Bit Error Rate (BER) assuming an Additive White Gaussian Noise interference model is evaluated as a function of Eb/No, the signal to noise ratio, and transmitted phase angles of the signals. The performance results of the direct bit detection receivers (DBDR) when compared to that of convectional phase measurement receivers demonstrate that DBDR's are optimum in BER sense. The simplicity of the receiver implementations and the BER of the delivered data make DBDR's attractive for high speed, spectrally efficient digital communication systems.

A General Sparse Tensor Framework for Electronic Structure Theory

DOE PAGES

Manzer, Samuel; Epifanovsky, Evgeny; Krylov, Anna I.; ...

2017-01-24

Linear-scaling algorithms must be developed in order to extend the domain of applicability of electronic structure theory to molecules of any desired size. But, the increasing complexity of modern linear-scaling methods makes code development and maintenance a significant challenge. A major contributor to this difficulty is the lack of robust software abstractions for handling block-sparse tensor operations. We therefore report the development of a highly efficient symbolic block-sparse tensor library in order to provide access to high-level software constructs to treat such problems. Our implementation supports arbitrary multi-dimensional sparsity in all input and output tensors. We then avoid cumbersome machine-generatedmore » code by implementing all functionality as a high-level symbolic C++ language library and demonstrate that our implementation attains very high performance for linear-scaling sparse tensor contractions.« less

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

Cognitive change in patients with Huntington disease on the Repeatable Battery for the Assessment of Neuropsychological Status.

PubMed

Beglinger, Leigh J; Duff, Kevin; Allison, Jessica; Theriault, Danielle; O'Rourke, Justin J F; Leserman, Anne; Paulsen, Jane S

2010-07-01

Huntington disease (HD) is a neurodegenerative disease associated with cognitive, motor, and psychiatric deterioration over time. Although there is currently no cure for HD, there has been a surge of clinical trials available to patients with HD over the past 5 years. However, cognitive measures have generally been lacking from these trials. A brief, repeatable neuropsychological battery is needed to assess cognitive endpoints. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) may be useful for assessing change in interventional studies or for clinical monitoring. A total of 38 patients with HD were assessed using the RBANS, other cognitive tests, and the standardized HD battery (Unified Huntington's Disease Rating Scale, UHDRS) at two clinic visits approximately 16 months apart. The RBANS Attention Index, as well as individual subtest scores on Coding, Digit Span, List Recognition, Figure Copy, and Figure Recall all declined significantly over this interval. Performance on the UHDRS cognitive tests (Symbol Digit Modalities; Stroop Color, and Stroop Word) also declined, as did functional capacity. Results suggest that cognitive changes were detected both on established cognitive tasks used in HD research and on the RBANS in patients with measurable functional decline. The RBANS provided additional information about other cognitive domains affected (e.g., memory) and may be a useful measure for tracking longitudinal change.

Fuzzy Logic Module of Convolutional Neural Network for Handwritten Digits Recognition

NASA Astrophysics Data System (ADS)

Popko, E. A.; Weinstein, I. A.

2016-08-01

Optical character recognition is one of the important issues in the field of pattern recognition. This paper presents a method for recognizing handwritten digits based on the modeling of convolutional neural network. The integrated fuzzy logic module based on a structural approach was developed. Used system architecture adjusted the output of the neural network to improve quality of symbol identification. It was shown that proposed algorithm was flexible and high recognition rate of 99.23% was achieved.

BCM-2.0 - The new version of computer code ;Basic Channeling with Mathematica©;

NASA Astrophysics Data System (ADS)

Abdrashitov, S. V.; Bogdanov, O. V.; Korotchenko, K. B.; Pivovarov, Yu. L.; Rozhkova, E. I.; Tukhfatullin, T. A.; Eikhorn, Yu. L.

2017-07-01

The new symbolic-numerical code devoted to investigation of the channeling phenomena in periodic potential of a crystal has been developed. The code has been written in Wolfram Language taking advantage of analytical programming method. Newly developed different packages were successfully applied to simulate scattering, radiation, electron-positron pair production and other effects connected with channeling of relativistic particles in aligned crystal. The result of the simulation has been validated against data from channeling experiments carried out at SAGA LS.

Aquarius Project: Research in the System Architecture of Accelerators for the High Performance Execution of Logic Programs.

DTIC Science & Technology

1991-05-31

benchmarks ............ .... . .. .. . . .. 220 Appendix G : Source code of the Aquarius Prolog compiler ........ . 224 Chapter I Introduction "You’re given...notation, a tool that is used throughout the compiler’s implementation. Appendix F lists the source code of the C and Prolog benchmarks. Appendix G lists the...source code of the compilcr. 5 "- standard form Prolog / a-sfomadon / head umrvln Convert to tmeikernel Prol g vrans~fonaon 1symbolic execution

A digital version of the 1970 U.S. Geological Survey topographic map of the San Francisco Bay region, three sheets, 1:125,000

USGS Publications Warehouse

Aitken, Douglas S.

1997-01-01

This Open-File report is a digital topographic map database. It contains a digital version of the 1970 U.S. Geological Survey topographic map of the San Francisco Bay Region (3 sheets), at a scale of 1:125,000. These ARC/INFO coverages are in vector format. The vectorization process has distorted characters representing letters and numbers, as well as some road and other symbols, making them difficult to read in some instances. This pamphlet serves to introduce and describe the digital data. There is no paper map included in the Open-File report. The content and character of the database and methods of obtaining it are described herein.

Characterization of a 300-GHz Transmission System for Digital Communications

NASA Astrophysics Data System (ADS)

Hudlička, Martin; Salhi, Mohammed; Kleine-Ostmann, Thomas; Schrader, Thorsten

2017-08-01

The paper presents the characterization of a 300-GHz transmission system for modern digital communications. The quality of the modulated signal at the output of the system (error vector magnitude, EVM) is measured using a vector signal analyzer. A method using a digital real-time oscilloscope and consecutive mathematical processing in a computer is shown for analysis of signals with bandwidths exceeding that of state-of-the-art vector signal analyzers. The uncertainty of EVM measured using the real-time oscilloscope is open to analysis. Behaviour of the 300-GHz transmission system is studied with respect to various modulation schemes and different signal symbol rates.

Target recognition and scene interpretation in image/video understanding systems based on network-symbolic models

NASA Astrophysics Data System (ADS)

Kuvich, Gary

2004-08-01

Vision is only a part of a system that converts visual information into knowledge structures. These structures drive the vision process, resolving ambiguity and uncertainty via feedback, and provide image understanding, which is an interpretation of visual information in terms of these knowledge models. These mechanisms provide a reliable recognition if the object is occluded or cannot be recognized as a whole. It is hard to split the entire system apart, and reliable solutions to the target recognition problems are possible only within the solution of a more generic Image Understanding Problem. Brain reduces informational and computational complexities, using implicit symbolic coding of features, hierarchical compression, and selective processing of visual information. Biologically inspired Network-Symbolic representation, where both systematic structural/logical methods and neural/statistical methods are parts of a single mechanism, is the most feasible for such models. It converts visual information into relational Network-Symbolic structures, avoiding artificial precise computations of 3-dimensional models. Network-Symbolic Transformations derive abstract structures, which allows for invariant recognition of an object as exemplar of a class. Active vision helps creating consistent models. Attention, separation of figure from ground and perceptual grouping are special kinds of network-symbolic transformations. Such Image/Video Understanding Systems will be reliably recognizing targets.

Direct Sequence Spread Spectrum (DSSS) Receiver, User Manual

DTIC Science & Technology

2008-01-01

sampled data is clocked in to correlator data registers and a comparison is made between the code and data register contents, producing a correlation ...symbol (equal to the processing gain Gp ) but need not be otherwise synchronised with the spreading codes . This allows a very long and noise- like PRBS...and Q channels are independently but synchronously sampled . Complex Real ADC FIR Filter Interpolator Acquisition Correlators

47 CFR 25.281 - Transmitter identification requirements for video uplink transmissions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... video uplink transmissions. 25.281 Section 25.281 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... identification requirements for video uplink transmissions. (a) Earth-to-space transmissions carrying video..., transmissions of fixed-frequency, digitally modulated video signals with a symbol rate of 128,000/s or more from...

40 CFR 1036.805 - Symbols, acronyms, and abbreviations.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... ASTM American Society for Testing and Materials. BTU British thermal units. CFR Code of Federal... pound. lbC pound carbon. LPG liquefied petroleum gas. Mg megagrams (10 6 grams, or one metric ton). MJ...

40 CFR 1036.805 - Symbols, acronyms, and abbreviations.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... ASTM American Society for Testing and Materials. BTU British thermal units. CFR Code of Federal... pound. lbC pound carbon. LPG liquefied petroleum gas. Mg megagrams (10 6 grams, or one metric ton). MJ...

40 CFR 1036.805 - Symbols, acronyms, and abbreviations.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... ASTM American Society for Testing and Materials. BTU British thermal units. CFR Code of Federal... pound. lbC pound carbon. LPG liquefied petroleum gas. Mg megagrams (10 6 grams, or one metric ton). MJ...

49 CFR 178.910 - Marking of Large Packagings.

Code of Federal Regulations, 2014 CFR

2014-10-01

... stamped or embossed, the capital letters “UN” may be applied instead of the symbol; (ii) The code number...) The country authorizing the allocation of the mark. The letters “USA” indicate that the Large...

49 CFR 178.910 - Marking of Large Packagings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... stamped or embossed, the capital letters “UN” may be applied instead of the symbol; (ii) The code number...) The country authorizing the allocation of the mark. The letters “USA” indicate that the Large...

Dynamical beam manipulation based on 2-bit digitally-controlled coding metasurface.

PubMed

Huang, Cheng; Sun, Bo; Pan, Wenbo; Cui, Jianhua; Wu, Xiaoyu; Luo, Xiangang

2017-02-08

Recently, a concept of digital metamaterials has been proposed to manipulate field distribution through proper spatial mixtures of digital metamaterial bits. Here, we present a design of 2-bit digitally-controlled coding metasurface that can effectively modulate the scattered electromagnetic wave and realize different far-field beams. Each meta-atom of this metasurface integrates two pin diodes, and by tuning their operating states, the metasurface has four phase responses of 0, π/2, π, and 3π/2, corresponding to four basic digital elements "00", "01", "10", and "11", respectively. By designing the coding sequence of the above digital element array, the reflected beam can be arbitrarily controlled. The proposed 2-bit digital metasurface has been demonstrated to possess capability of achieving beam deflection, multi-beam and beam diffusion, and the dynamical switching of these different scattering patterns is completed by a programmable electric source.

Dynamical beam manipulation based on 2-bit digitally-controlled coding metasurface

PubMed Central

Huang, Cheng; Sun, Bo; Pan, Wenbo; Cui, Jianhua; Wu, Xiaoyu; Luo, Xiangang

2017-01-01

Recently, a concept of digital metamaterials has been proposed to manipulate field distribution through proper spatial mixtures of digital metamaterial bits. Here, we present a design of 2-bit digitally-controlled coding metasurface that can effectively modulate the scattered electromagnetic wave and realize different far-field beams. Each meta-atom of this metasurface integrates two pin diodes, and by tuning their operating states, the metasurface has four phase responses of 0, π/2, π, and 3π/2, corresponding to four basic digital elements “00”, “01”, “10”, and “11”, respectively. By designing the coding sequence of the above digital element array, the reflected beam can be arbitrarily controlled. The proposed 2-bit digital metasurface has been demonstrated to possess capability of achieving beam deflection, multi-beam and beam diffusion, and the dynamical switching of these different scattering patterns is completed by a programmable electric source. PMID:28176870

Nonlinear, nonbinary cyclic group codes

NASA Technical Reports Server (NTRS)

Solomon, G.

1992-01-01

New cyclic group codes of length 2(exp m) - 1 over (m - j)-bit symbols are introduced. These codes can be systematically encoded and decoded algebraically. The code rates are very close to Reed-Solomon (RS) codes and are much better than Bose-Chaudhuri-Hocquenghem (BCH) codes (a former alternative). The binary (m - j)-tuples are identified with a subgroup of the binary m-tuples which represents the field GF(2 exp m). Encoding is systematic and involves a two-stage procedure consisting of the usual linear feedback register (using the division or check polynomial) and a small table lookup. For low rates, a second shift-register encoding operation may be invoked. Decoding uses the RS error-correcting procedures for the m-tuple codes for m = 4, 5, and 6.

Syndrome source coding and its universal generalization

NASA Technical Reports Server (NTRS)

Ancheta, T. C., Jr.

1975-01-01

A method of using error-correcting codes to obtain data compression, called syndrome-source-coding, is described in which the source sequence is treated as an error pattern whose syndrome forms the compressed data. It is shown that syndrome-source-coding can achieve arbitrarily small distortion with the number of compressed digits per source digit arbitrarily close to the entropy of a binary memoryless source. A universal generalization of syndrome-source-coding is formulated which provides robustly-effective, distortionless, coding of source ensembles.

Preventing SQL Code Injection by Combining Static and Runtime Analysis

DTIC Science & Technology

2008-05-01

attacker changes the developer’s intended structure of an SQ L com- mand by inserting new SQ L keywords or operators. (Su and Wasser - mann provide a...FROM b o o k s WHERE a u t h o r = ’ ’ GROUP BY r a t i n g We use symbol as a placeholder for the indeterminate part of the command (in this...dialects of SQL.) In our model, we mark transitions that correspond to externally defined strings with the symbol . To illustrate, Figure 2 shows the SQL

Graphic/symbol segmentation for Group 4 facsimile systems

NASA Astrophysics Data System (ADS)

Deutermann, A. R.

1982-04-01

The purpose of this study was to examine possible techniques for and symbol areas, and assemble a code that represents the entire document. Parameters to be considered include compression, commonality with facsimile and TELETEX* transmissions, and complexity of implementation. Six segmentation technique were selected for analysis. The techniques were designed to differ from each other as much as possible, so as to display a wide variety of characteristics. For each technique, many minor modifications would be possible, but it is not expected that these modifications would alter the conclusions drawn from the study.

Combining Symbolic Computation and Theorem Proving: Some Problems of Ramanujan

DTIC Science & Technology

1994-01-01

1994 CMU-CS--94- 103 ¶ DTIC MAY 0e o99 c -rnepe Combining symbolic computation and theorem proving: some problems of Ramanujan Edmund Clarke Xudong Zhao...Research and Development Center, Aeronautical Systems Division (AFSC), U.S. Air Force, Wright-Patterson AFB, Ohio 45433-6543 under Contract F33615-90- C ...Availability Codes n n = f Avail and Ior7. k= f(k) = _L k~of(nk Dist Special 8. =I f (k + c ) =_k=,+ I f (k) A .[ 3. List of problems The list of challenge

An Orbital Angular Momentum (OAM) Mode Reconfigurable Antenna for Channel Capacity Improvement and Digital Data Encoding.

PubMed

Liu, Baiyang; Lin, Guoying; Cui, Yuehui; Li, RongLin

2017-08-29

For purpose of utilizing orbital angular momentum (OAM) mode diversity, multiple OAM beams should be generated preferably by a single antenna. In this paper, an OAM mode reconfigurable antenna is proposed. Different from the existed OAM antennas with multiple ports for multiple OAM modes transmitting, the proposed antenna with only a single port, but it can be used to transmit mode 1 or mode -1 OAM beams arbitrary by controlling the PIN diodes on the feeding network through a programmable microcontroller which control by a remote controller. Simulation and measurement results such as return loss, near-field and far-field radiation patterns of two operating states for mode 1 and mode -1, and OAM mode orthogonality are given. The proposed antenna can serve as a candidate for utilizing OAM diversity, namely phase diversity to increase channel capacity at 2.4 GHz. Moreover, an OAM-mode based encoding method is experimentally carried out by the proposed OAM mode reconfigurable antenna, the digital data are encoded and decoded by different OAM modes. At the transmitter, the proposed OAM mode reconfigurable antenna is used to encode the digital data, data symbol 0 and 1 are mapped to OAM mode 1 and mode -1, respectively. At the receiver, the data symbols are decoded by phase gradient method.

A Comparative Study on Diagnostic Accuracy of Colour Coded Digital Images, Direct Digital Images and Conventional Radiographs for Periapical Lesions – An In Vitro Study

PubMed Central

Mubeen; K.R., Vijayalakshmi; Bhuyan, Sanat Kumar; Panigrahi, Rajat G; Priyadarshini, Smita R; Misra, Satyaranjan; Singh, Chandravir

2014-01-01

Objectives: The identification and radiographic interpretation of periapical bone lesions is important for accurate diagnosis and treatment. The present study was undertaken to study the feasibility and diagnostic accuracy of colour coded digital radiographs in terms of presence and size of lesion and to compare the diagnostic accuracy of colour coded digital images with direct digital images and conventional radiographs for assessing periapical lesions. Materials and Methods: Sixty human dry cadaver hemimandibles were obtained and periapical lesions were created in first and second premolar teeth at the junction of cancellous and cortical bone using a micromotor handpiece and carbide burs of sizes 2, 4 and 6. After each successive use of round burs, a conventional, RVG and colour coded image was taken for each specimen. All the images were evaluated by three observers. The diagnostic accuracy for each bur and image mode was calculated statistically. Results: Our results showed good interobserver (kappa > 0.61) agreement for the different radiographic techniques and for the different bur sizes. Conventional Radiography outperformed Digital Radiography in diagnosing periapical lesions made with Size two bur. Both were equally diagnostic for lesions made with larger bur sizes. Colour coding method was least accurate among all the techniques. Conclusion: Conventional radiography traditionally forms the backbone in the diagnosis, treatment planning and follow-up of periapical lesions. Direct digital imaging is an efficient technique, in diagnostic sense. Colour coding of digital radiography was feasible but less accurate however, this imaging technique, like any other, needs to be studied continuously with the emphasis on safety of patients and diagnostic quality of images. PMID:25584318

High signal intensity on magnetic resonance imaging is a better predictor of neurobehavioral performances than blood manganese in asymptomatic welders.

PubMed

Chang, Yongmin; Kim, Yangho; Woo, Seung-Tae; Song, Hui-Jin; Kim, Suk Hwan; Lee, Hun; Kwon, Young Joo; Ahn, Joon-Ho; Park, Sin-Jae; Chung, In-Sung; Jeong, Kyoung Sook

2009-07-01

The aim of the study was to evaluate subclinical neurological effects in welders, using an extensive list of neurobehavioral batteries and determine if there is a link between pallidal index (PI) and subclinical neurobehavioral effects in the spectrum of manganese (Mn) symptomatology. A total of 43 asymptomatic male welders and 29 age- and sex-matched healthy control individuals completed questionnaires, and underwent blood examinations, brain magnetic resonance imaging (MRI) scans, and a wide range of neurobehavioral examinations. Digit symbol, auditory verbal learning test (delayed recall), complex figure test (copy and immediate recall), digit span, verbal fluency test, Stroop test, grooved pegboard, finger tapping, frequency dispersion and harmonic index of tremor, and maximum frequency of hand coordination showed differences between welders and control individuals. No differences were noted for simple reaction time, postural sway, smell test, and profile of mood states (POMS). Blood Mn levels were shown to be significantly associated with grooved pegboard (dominant hand) and complex figure test (copy) results. PI was significantly associated with digit symbol, digit span backward, Stroop Word and Stroop error index, and grooved pegboard (dominant hand) results. The present findings that there were significant correlations between several neurobehavioral deficits and PI as well as blood Mn suggest that they may be attributed to Mn exposure in welding fumes. The present study also shows that PI is a better predictor of neurobehavioral performance than blood Mn levels in asymptomatic welders.

Advanced compilation techniques in the PARADIGM compiler for distributed-memory multicomputers

NASA Technical Reports Server (NTRS)

Su, Ernesto; Lain, Antonio; Ramaswamy, Shankar; Palermo, Daniel J.; Hodges, Eugene W., IV; Banerjee, Prithviraj

1995-01-01

The PARADIGM compiler project provides an automated means to parallelize programs, written in a serial programming model, for efficient execution on distributed-memory multicomputers. .A previous implementation of the compiler based on the PTD representation allowed symbolic array sizes, affine loop bounds and array subscripts, and variable number of processors, provided that arrays were single or multi-dimensionally block distributed. The techniques presented here extend the compiler to also accept multidimensional cyclic and block-cyclic distributions within a uniform symbolic framework. These extensions demand more sophisticated symbolic manipulation capabilities. A novel aspect of our approach is to meet this demand by interfacing PARADIGM with a powerful off-the-shelf symbolic package, Mathematica. This paper describes some of the Mathematica routines that performs various transformations, shows how they are invoked and used by the compiler to overcome the new challenges, and presents experimental results for code involving cyclic and block-cyclic arrays as evidence of the feasibility of the approach.

Feedback-Driven Dynamic Invariant Discovery

NASA Technical Reports Server (NTRS)

Zhang, Lingming; Yang, Guowei; Rungta, Neha S.; Person, Suzette; Khurshid, Sarfraz

2014-01-01

Program invariants can help software developers identify program properties that must be preserved as the software evolves, however, formulating correct invariants can be challenging. In this work, we introduce iDiscovery, a technique which leverages symbolic execution to improve the quality of dynamically discovered invariants computed by Daikon. Candidate invariants generated by Daikon are synthesized into assertions and instrumented onto the program. The instrumented code is executed symbolically to generate new test cases that are fed back to Daikon to help further re ne the set of candidate invariants. This feedback loop is executed until a x-point is reached. To mitigate the cost of symbolic execution, we present optimizations to prune the symbolic state space and to reduce the complexity of the generated path conditions. We also leverage recent advances in constraint solution reuse techniques to avoid computing results for the same constraints across iterations. Experimental results show that iDiscovery converges to a set of higher quality invariants compared to the initial set of candidate invariants in a small number of iterations.

Is Order the Defining Feature of Magnitude Representation? An ERP Study on Learning Numerical Magnitude and Spatial Order of Artificial Symbols

PubMed Central

Zhao, Hui; Chen, Chuansheng; Zhang, Hongchuan; Zhou, Xinlin; Mei, Leilei; Chen, Chunhui; Chen, Lan; Cao, Zhongyu; Dong, Qi

2012-01-01

Using an artificial-number learning paradigm and the ERP technique, the present study investigated neural mechanisms involved in the learning of magnitude and spatial order. 54 college students were divided into 2 groups matched in age, gender, and school major. One group was asked to learn the associations between magnitude (dot patterns) and the meaningless Gibson symbols, and the other group learned the associations between spatial order (horizontal positions on the screen) and the same set of symbols. Results revealed differentiated neural mechanisms underlying the learning processes of symbolic magnitude and spatial order. Compared to magnitude learning, spatial-order learning showed a later and reversed distance effect. Furthermore, an analysis of the order-priming effect showed that order was not inherent to the learning of magnitude. Results of this study showed a dissociation between magnitude and order, which supports the numerosity code hypothesis of mental representations of magnitude. PMID:23185363

Tutorial on Reed-Solomon error correction coding

NASA Technical Reports Server (NTRS)

Geisel, William A.

1990-01-01

This tutorial attempts to provide a frank, step-by-step approach to Reed-Solomon (RS) error correction coding. RS encoding and RS decoding both with and without erasing code symbols are emphasized. There is no need to present rigorous proofs and extreme mathematical detail. Rather, the simple concepts of groups and fields, specifically Galois fields, are presented with a minimum of complexity. Before RS codes are presented, other block codes are presented as a technical introduction into coding. A primitive (15, 9) RS coding example is then completely developed from start to finish, demonstrating the encoding and decoding calculations and a derivation of the famous error-locator polynomial. The objective is to present practical information about Reed-Solomon coding in a manner such that it can be easily understood.

Discussion on LDPC Codes and Uplink Coding

NASA Technical Reports Server (NTRS)

Andrews, Ken; Divsalar, Dariush; Dolinar, Sam; Moision, Bruce; Hamkins, Jon; Pollara, Fabrizio

2007-01-01

This slide presentation reviews the progress that the workgroup on Low-Density Parity-Check (LDPC) for space link coding. The workgroup is tasked with developing and recommending new error correcting codes for near-Earth, Lunar, and deep space applications. Included in the presentation is a summary of the technical progress of the workgroup. Charts that show the LDPC decoder sensitivity to symbol scaling errors are reviewed, as well as a chart showing the performance of several frame synchronizer algorithms compared to that of some good codes and LDPC decoder tests at ESTL. Also reviewed is a study on Coding, Modulation, and Link Protocol (CMLP), and the recommended codes. A design for the Pseudo-Randomizer with LDPC Decoder and CRC is also reviewed. A chart that summarizes the three proposed coding systems is also presented.

Intellectual Performance as a Function of Repression and Menstrual Cycle.

ERIC Educational Resources Information Center

Englander-Golden, Paula; And Others

Performance on complex (Space Relations and Verbal Reasoning) and simple (Digit Symbol) tests was investigated as a function of Byrne's Repression-Sensitization (RS) dimension, phase of menstrual cycle and premenstrual-menstrual (PM) symptomatology in a group of females not taking oral contraceptives. Two control groups, consisting of males and…

The Impact of Chronic Pesticide Exposure on Neuropsychological Functioning

ERIC Educational Resources Information Center

Schultz, Caitlin G.; Ferraro, F. Richard

2013-01-01

This study compared neuropsychological test performance of individuals (n = 18) with an occupational history of pesticide exposure to individuals (n = 35) with no such exposure history. Results showed that a history of pesticide-related occupation exposure led to deficits in only Digit Symbol performance. Additionally, the correlation between…

The Picture Exchange Communication System: Digital Photographs versus Picture Symbols

ERIC Educational Resources Information Center

Jonaitis, Carmen

2011-01-01

The Picture Exchange Communication System (PECS) is an augmentative and alternative system (AAC) used to improve and increase communication for children with Autism Spectrum Disorder (ASD) and other developmental disorders. Research addressing the efficacy of this system is increasing; however, there is limited information published that evaluates…

Age Effects on Wechsler Adult Intelligence Scale-Revised Tests.

ERIC Educational Resources Information Center

Sattler, Jerome M.

1982-01-01

Studied age norms for 11 individual Wechsler Adult Intelligence Scale-Revised (WAIS-R) tests. Digit Symbol showed the most decline. Results suggest that fluid intelligence, as measured by the performance scale tests, shows more of a decline with age than crystallized intelligence, as measured by the verbal scale tests. (Author)

Education, Technology, and the "New" Knowledge Economy: Views from Bongoland

ERIC Educational Resources Information Center

Stambach, Amy; Malekela, George A.

2006-01-01

The concept of bridging the digital divide between Africa and the rest of the world draws symbolically on nineteenth century diffusion theories of linear progress and twentieth-century theories of modernization and development. This paper examines information and communication technology (ICT) policies and public-access postings on…

Let Us Make the Table Periodic.

ERIC Educational Resources Information Center

Campbell, J. Arthur

1989-01-01

An approach to teaching the properties of the elements and their arrangement in the periodic table is suggested. Discussed are symbols for the elements, format of the table, and coding the properties of the elements on the table. (CW)

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.

A family of chaotic pure analog coding schemes based on baker's map function

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Jing; Lu, Xuanxuan; Yuen, Chau; Wu, Jun

2015-12-01

This paper considers a family of pure analog coding schemes constructed from dynamic systems which are governed by chaotic functions—baker's map function and its variants. Various decoding methods, including maximum likelihood (ML), minimum mean square error (MMSE), and mixed ML-MMSE decoding algorithms, have been developed for these novel encoding schemes. The proposed mirrored baker's and single-input baker's analog codes perform a balanced protection against the fold error (large distortion) and weak distortion and outperform the classical chaotic analog coding and analog joint source-channel coding schemes in literature. Compared to the conventional digital communication system, where quantization and digital error correction codes are used, the proposed analog coding system has graceful performance evolution, low decoding latency, and no quantization noise. Numerical results show that under the same bandwidth expansion, the proposed analog system outperforms the digital ones over a wide signal-to-noise (SNR) range.

Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering.

PubMed

Chen, Ke; Feng, Yijun; Yang, Zhongjie; Cui, Li; Zhao, Junming; Zhu, Bo; Jiang, Tian

2016-10-24

Ultrathin metasurface compromising various sub-wavelength meta-particles offers promising advantages in controlling electromagnetic wave by spatially manipulating the wavefront characteristics across the interface. The recently proposed digital coding metasurface could even simplify the design and optimization procedures due to the digitalization of the meta-particle geometry. However, current attempts to implement the digital metasurface still utilize several structural meta-particles to obtain certain electromagnetic responses, and requiring time-consuming optimization especially in multi-bits coding designs. In this regard, we present herein utilizing geometric phase based single structured meta-particle with various orientations to achieve either 1-bit or multi-bits digital metasurface. Particular electromagnetic wave scattering patterns dependent on the incident polarizations can be tailored by the encoded metasurfaces with regular sequences. On the contrast, polarization insensitive diffusion-like scattering can also been successfully achieved by digital metasurface encoded with randomly distributed coding sequences leading to substantial suppression of backward scattering in a broadband microwave frequency. The proposed digital metasurfaces provide simple designs and reveal new opportunities for controlling electromagnetic wave scattering with or without polarization dependence.

Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering

PubMed Central

Chen, Ke; Feng, Yijun; Yang, Zhongjie; Cui, Li; Zhao, Junming; Zhu, Bo; Jiang, Tian

2016-01-01

Ultrathin metasurface compromising various sub-wavelength meta-particles offers promising advantages in controlling electromagnetic wave by spatially manipulating the wavefront characteristics across the interface. The recently proposed digital coding metasurface could even simplify the design and optimization procedures due to the digitalization of the meta-particle geometry. However, current attempts to implement the digital metasurface still utilize several structural meta-particles to obtain certain electromagnetic responses, and requiring time-consuming optimization especially in multi-bits coding designs. In this regard, we present herein utilizing geometric phase based single structured meta-particle with various orientations to achieve either 1-bit or multi-bits digital metasurface. Particular electromagnetic wave scattering patterns dependent on the incident polarizations can be tailored by the encoded metasurfaces with regular sequences. On the contrast, polarization insensitive diffusion-like scattering can also been successfully achieved by digital metasurface encoded with randomly distributed coding sequences leading to substantial suppression of backward scattering in a broadband microwave frequency. The proposed digital metasurfaces provide simple designs and reveal new opportunities for controlling electromagnetic wave scattering with or without polarization dependence. PMID:27775064

Flexible digital modulation and coding synthesis for satellite communications

NASA Technical Reports Server (NTRS)

Vanderaar, Mark; Budinger, James; Hoerig, Craig; Tague, John

1991-01-01

An architecture and a hardware prototype of a flexible trellis modem/codec (FTMC) transmitter are presented. The theory of operation is built upon a pragmatic approach to trellis-coded modulation that emphasizes power and spectral efficiency. The system incorporates programmable modulation formats, variations of trellis-coding, digital baseband pulse-shaping, and digital channel precompensation. The modulation formats examined include (uncoded and coded) binary phase shift keying (BPSK), quatenary phase shift keying (QPSK), octal phase shift keying (8PSK), 16-ary quadrature amplitude modulation (16-QAM), and quadrature quadrature phase shift keying (Q squared PSK) at programmable rates up to 20 megabits per second (Mbps). The FTMC is part of the developing test bed to quantify modulation and coding concepts.

Masked priming effects are modulated by expertise in the script.

PubMed

Perea, Manuel; Abu Mallouh, Reem; Garcı A-Orza, Javier; Carreiras, Manuel

2011-05-01

In a recent study using a masked priming same-different matching task, Garcı´a-Orza, Perea, and Munoz (2010) found a transposition priming effect for letter strings, digit strings, and symbol strings, but not for strings of pseudoletters (i.e., EPRI-ERPI produced similar response times to the control pair EDBI-ERPI). They argued that the mechanism responsible for position coding in masked priming is not operative with those "objects" whose identity cannot be attained rapidly. To assess this hypothesis, Experiment 1 examined masked priming effects in Arabic for native speakers of Arabic, whereas participants in Experiments 2 and 3 were lower intermediate learners of Arabic and readers with no knowledge of Arabic, respectively. Results showed a masked priming effect only for readers who are familiar with the Arabic script. Furthermore, transposed-letter priming in native speakers of Arabic only occurred when the order of the root letters was kept intact. In Experiments 3-7, we examined why masked repetition priming is absent for readers who are unfamiliar with the Arabic script. We discuss the implications of these findings for models of visual-word recognition.

Scientific iconoclasm and active imagination: synthetic cells as techno-scientific mandalas.

PubMed

Zwart, Hub

2018-05-14

Metaphors allow us to come to terms with abstract and complex information, by comparing it to something which is structured, familiar and concrete. Although modern science is "iconoclastic", as Gaston Bachelard phrases it (i.e. bent on replacing living entities by symbolic data: e.g. biochemical and mathematical symbols and codes), scientists are at the same time prolific producers of metaphoric images themselves. Synthetic biology is an outstanding example of a technoscientific discourse replete with metaphors, including textual metaphors such as the "Morse code" of life, the "barcode" of life and the "book" of life. This paper focuses on a different type of metaphor, however, namely on the archetypal metaphor of the mandala as a symbol of restored unity and wholeness. Notably, mandala images emerge in textual materials (papers, posters, PowerPoints, etc.) related to one of the new "frontiers" of contemporary technoscience, namely the building of a synthetic cell: a laboratory artefact that functions like a cell and is even able to replicate itself. The mandala symbol suggests that, after living systems have been successfully reduced to the elementary building blocks and barcodes of life, the time has now come to put these fragments together again. We can only claim to understand life, synthetic cell experts argue, if we are able to technically reproduce a fully functioning cell. This holistic turn towards the cell as a meaningful whole (a total work of techno-art) also requires convergence at the "subject pole": the building of a synthetic cell as a practice of the self, representing a turn towards integration, of multiple perspectives and various forms of expertise.

The "Wow! signal" of the terrestrial genetic code

NASA Astrophysics Data System (ADS)

shCherbak, Vladimir I.; Makukov, Maxim A.

2013-05-01

It has been repeatedly proposed to expand the scope for SETI, and one of the suggested alternatives to radio is the biological media. Genomic DNA is already used on Earth to store non-biological information. Though smaller in capacity, but stronger in noise immunity is the genetic code. The code is a flexible mapping between codons and amino acids, and this flexibility allows modifying the code artificially. But once fixed, the code might stay unchanged over cosmological timescales; in fact, it is the most durable construct known. Therefore it represents an exceptionally reliable storage for an intelligent signature, if that conforms to biological and thermodynamic requirements. As the actual scenario for the origin of terrestrial life is far from being settled, the proposal that it might have been seeded intentionally cannot be ruled out. A statistically strong intelligent-like "signal" in the genetic code is then a testable consequence of such scenario. Here we show that the terrestrial code displays a thorough precision-type orderliness matching the criteria to be considered an informational signal. Simple arrangements of the code reveal an ensemble of arithmetical and ideographical patterns of the same symbolic language. Accurate and systematic, these underlying patterns appear as a product of precision logic and nontrivial computing rather than of stochastic processes (the null hypothesis that they are due to chance coupled with presumable evolutionary pathways is rejected with P-value < 10-13). The patterns are profound to the extent that the code mapping itself is uniquely deduced from their algebraic representation. The signal displays readily recognizable hallmarks of artificiality, among which are the symbol of zero, the privileged decimal syntax and semantical symmetries. Besides, extraction of the signal involves logically straightforward but abstract operations, making the patterns essentially irreducible to any natural origin. Plausible ways of embedding the signal into the code and possible interpretation of its content are discussed. Overall, while the code is nearly optimized biologically, its limited capacity is used extremely efficiently to pass non-biological information.

A digitally implemented preambleless demodulator for maritime and mobile data communications

NASA Astrophysics Data System (ADS)

Chalmers, Harvey; Shenoy, Ajit; Verahrami, Farhad B.

The hardware design and software algorithms for a low-bit-rate, low-cost, all-digital preambleless demodulator are described. The demodulator operates under severe high-noise conditions, fast Doppler frequency shifts, large frequency offsets, and multipath fading. Sophisticated algorithms, including a fast Fourier transform (FFT)-based burst acquisition algorithm, a cycle-slip resistant carrier phase tracker, an innovative Doppler tracker, and a fast acquisition symbol synchronizer, were developed and extensively simulated for reliable burst reception. The compact digital signal processor (DSP)-based demodulator hardware uses a unique personal computer test interface for downloading test data files. The demodulator test results demonstrate a near-ideal performance within 0.2 dB of theory.

40 CFR 1051.805 - What symbols, acronyms, and abbreviations does this part use?

Code of Federal Regulations, 2011 CFR

2011-07-01

...—American Society for Testing and Materials. ATV—all-terrain vehicle. cc—cubic centimeters. CFR—Code of...—pounds per square inches of gauge pressure. rpm—revolutions per minute. SAE—Society of Automotive...

Shaping electromagnetic waves using software-automatically-designed metasurfaces.

PubMed

Zhang, Qian; Wan, Xiang; Liu, Shuo; Yuan Yin, Jia; Zhang, Lei; Jun Cui, Tie

2017-06-15

We present a fully digital procedure of designing reflective coding metasurfaces to shape reflected electromagnetic waves. The design procedure is completely automatic, controlled by a personal computer. In details, the macro coding units of metasurface are automatically divided into several types (e.g. two types for 1-bit coding, four types for 2-bit coding, etc.), and each type of the macro coding units is formed by discretely random arrangement of micro coding units. By combining an optimization algorithm and commercial electromagnetic software, the digital patterns of the macro coding units are optimized to possess constant phase difference for the reflected waves. The apertures of the designed reflective metasurfaces are formed by arranging the macro coding units with certain coding sequence. To experimentally verify the performance, a coding metasurface is fabricated by automatically designing two digital 1-bit unit cells, which are arranged in array to constitute a periodic coding metasurface to generate the required four-beam radiations with specific directions. Two complicated functional metasurfaces with circularly- and elliptically-shaped radiation beams are realized by automatically designing 4-bit macro coding units, showing excellent performance of the automatic designs by software. The proposed method provides a smart tool to realize various functional devices and systems automatically.

Correction to Kreuzbauer, King, and Basu (2015).

PubMed

2015-08-01

Reports an error in "The Mind in the Object-Psychological Valuation of Materialized Human Expression" by Robert Kreuzbauer, Dan King and Shankha Basu (Journal of Experimental Psychology: General, Advanced Online Publication, Jun 15, 2015, np). In the article the labels on the X-axis of Figure 1 "Remove Variance" and "Preserve Variance" should be switched. (The following abstract of the original article appeared in record 2015-26264-001.) Symbolic material objects such as art or certain artifacts (e.g., fine pottery, jewelry) share one common element: The combination of generating an expression, and the materialization of this expression in the object. This explains why people place a much greater value on handmade over machine-made objects, and originals over duplicates. We show that this mechanism occurs when a material object's symbolic property is salient and when the creator (artist or craftsman) is perceived to have agency control over the 1-to-1 materialized expression in the object. Coactivation of these 2 factors causes the object to be perceived as having high value because it is seen as the embodied representation of the creator's unique personal expression. In 6 experiments, subjects rated objects in various object categories, which varied on the type of object property (symbolic, functional, aesthetic), the production procedure (handmade, machine-made, analog, digital) and the origin of the symbolic information (person or software). The studies showed that the proposed mechanism applies to symbolic, but not to functional or aesthetic material objects. Furthermore, they show that this specific form of symbolic object valuation could not be explained by various other related psychological theories (e.g., uniqueness, scarcity, physical touching, creative performance). Our research provides a universal framework that identifies a core mechanism for explaining judgments of value for one of our most uniquely human symbolic object categories. (c) 2015 APA, all rights reserved).

The mind in the object-Psychological valuation of materialized human expression.

PubMed

Kreuzbauer, Robert; King, Dan; Basu, Shankha

2015-08-01

[Correction Notice: An Erratum for this article was reported in Vol 144(4) of Journal of Experimental Psychology: General (see record 2015-33206-002). In the article the labels on the X-axis of Figure 1 "Remove Variance" and "Preserve Variance" should be switched.] Symbolic material objects such as art or certain artifacts (e.g., fine pottery, jewelry) share one common element: The combination of generating an expression, and the materialization of this expression in the object. This explains why people place a much greater value on handmade over machine-made objects, and originals over duplicates. We show that this mechanism occurs when a material object's symbolic property is salient and when the creator (artist or craftsman) is perceived to have agency control over the 1-to-1 materialized expression in the object. Coactivation of these 2 factors causes the object to be perceived as having high value because it is seen as the embodied representation of the creator's unique personal expression. In 6 experiments, subjects rated objects in various object categories, which varied on the type of object property (symbolic, functional, aesthetic), the production procedure (handmade, machine-made, analog, digital) and the origin of the symbolic information (person or software). The studies showed that the proposed mechanism applies to symbolic, but not to functional or aesthetic material objects. Furthermore, they show that this specific form of symbolic object valuation could not be explained by various other related psychological theories (e.g., uniqueness, scarcity, physical touching, creative performance). Our research provides a universal framework that identifies a core mechanism for explaining judgments of value for one of our most uniquely human symbolic object categories. (c) 2015 APA, all rights reserved).

UID...Leaving Its Mark on the Universe

NASA Technical Reports Server (NTRS)

Schramm, Harry F., Jr.

2008-01-01

Since 1975 bar codes on products at the retail counter have been accepted as the standard for entering product identity for price determination. Since the beginning of the 21 st century, the Data Matrix symbol has become accepted as the bar code format that is marked directly on a part, assembly or product that is durable enough to identify that item for its lifetime. NASA began the studies for direct part marking Data Matrix symbols on parts during the Return to Flight activities after the Challenger Accident. Over the 20 year period that has elapsed since Challenger, a mountain of studies, analyses and focused problem solutions developed by and for NASA have brought about world changing results. NASA Technical Standard 6002 and NASA Handbook 6003 for Direct Part Marking Data Matrix Symbols on Aerospace Parts have formed the basis for most other standards on part marking internationally. NASA and its commercial partners have developed numerous products and methods that addressed the difficulties of collecting part identification in aerospace operations. These products enabled the marking of Data Matrix symbols in virtually every situation and the reading of symbols at great distances, severe angles, under paint and in the dark without a light. Even unmarkable delicate parts now have a process to apply a chemical mixture, recently trademarked as Nanocodes, that can be converted to Data Matrix information through software. The accompanying intellectual property is protected by ten patents, several of which are licensed. Direct marking Data Matrix on NASA parts dramatically decreases data entry errors and the number of parts that go through their life cycle unmarked, two major threats to sound configuration management and flight safety. NASA is said to only have people and stuff with information connecting them. Data Matrix is one of the most significant improvements since Challenger to the safety and reliability of that connection.

UID...Now That's Gonna Leave A Mark

NASA Technical Reports Server (NTRS)

Schramm, Harry F., Jr.

2007-01-01

Since 1975 bar codes on products at the retail counter have been accepted as the standard for entering product identity for price determination. Since the beginning of the 21st century, the Data Matrix symbol has become accepted as the bar code format that is marked directly on a part, assembly or product that is durable enough to identify that item for its lifetime. NASA began the studies for direct part marking Data Matrix symbols on parts during the Return to Flight activities after the Challenger Accident. Over the 20 year period that has elapsed since Challenger, a mountain of studies, analyses and focused problem solutions developed by and for NASA have brought about world changing results. NASA Technical Standard 6002 and NASA Handbook 6003 for Direct Part Marking Data Matrix Symbols on Aerospace Parts have formed the basis for most other standards on part marking internationally. NASA and its commercial partners have developed numerous products and methods that addressed the difficulties of collecting part identification in aerospace operations. These products enabled the marking of Data Matrix symbols in virtually every situation and the reading of symbols at great distances, severe angles, under paint and in the dark without a light. Even unmarkable delicate parts now have a process to apply a chemical mixture, recently trademarked as Nanocodes, that can be converted to Data Matrix information through software. The accompanying intellectual property is protected by ten patents, several of which are licensed. Direct marking Data Matrix on NASA parts dramatically decreases data entry errors and the number ofparts that go through their life cycle unmarked, two major threats to sound configuration management and flight safety. NASA is said to only have people and stuff with information connecting them. Data Matrix is one of the most significant improvements since Challenger to the safety and reliability of that connection.

UID...Now That's Gonna Leave a Mark

NASA Technical Reports Server (NTRS)

Schramm, Harry F.

2008-01-01

Since 1975 bar codes on products at the retail counter have been accepted as the standard for entering product identity for price determination. Since the beginning of the 21st century, the Data Matrix symbol has become accepted as the bar code format that is marked directly on a part, assembly or product that is durable enough to identify that item for its lifetime. NASA began the studies for direct part marking Data Matrix symbols on parts during the Return to Flight activities after the Challenger Accident. Over the 20 year period that has elapsed since Challenger, a mountain of studies, analyses and focused problem solutions developed by and for NASA have brought about world changing results. NASA Technical Standard 6002 and NASA Handbook 6003 for Direct Part Marking Data Matrix Symbols on Aerospace Parts have formed the basis for most other standards on part marking internationally. NASA and its commercial partners have developed numerous products and methods that addressed the difficulties of collecting part identification in aerospace operations. These products enabled the marking of Data Matrix symbols in virtually every situation and the reading of symbols at great distances, severe angles, under paint and in the dark without a light. Even unmarkable delicate parts now have a process to apply a chemical mixture, recently trademarked as Nanocodes, that can be converted to Data Matrix information through software. The accompanying intellectual property is protected by ten patents, several of which are licensed. Direct marking Data Matrix on NASA parts dramatically decreases data entry errors and the number of parts that go through their life cycle unmarked, two major threats to sound configuration management and flight safety. NASA is said to only have people and stuff with information connecting them. Data Matrix is one of the most significant improvements since Challenger to the safety and reliability of that connection.

UID....Now That's Gonna Leave A Mark

NASA Technical Reports Server (NTRS)

Schramm, Harry F., Jr.

2008-01-01

Since 1975 bar codes on products at the retail counter have been accepted as the standard for entering product identity for price determination. Since the beginning of the 21 st century, the Data Matrix symbol has become accepted as the bar code format that is marked directly on a part, assembly or product that is durable enough to identify that item for its lifetime. NASA began the studies for direct part marking Data Matrix symbols on parts during the Return to Flight activities after the Challenger Accident. Over the 20 year period that has elapsed since Challenger, a mountain of studies, analyses and focused problem solutions developed by and for NASA have brought about world changing results. NASA Technical Standard 6002 and NASA Handbook 6003 for Direct Part Marking Data Matrix Symbols on Aerospace Parts have formed the basis for most other standards on part marking internationally. NASA and its commercial partners have developed numerous products and methods that addressed the difficulties of collecting part identification in aerospace operations. These products enabled the marking of Data Matrix symbols in virtually every situation and the reading of symbols at great distances, severe angles, under paint and in the dark without a light. Even unmarkable delicate parts now have a process to apply a chemical mixture, recently trademarked as Nanocodes, that can be converted to Data Matrix information through software. The accompanying intellectual property is protected by ten patents, several of which are licensed. Direct marking Data Matrix on NASA parts dramatically decreases data entry errors and the number of parts that go through their life cycle unmarked, two major threats to sound configuration management and flight safety. NASA is said to only have people and stuff with information connecting them. Data Matrix is one of the most significant improvements since Challenger to the safety and reliability of that connection.

UID.. .Now That's Gonna Leave A Mark

NASA Technical Reports Server (NTRS)

Schramm, Fred

2006-01-01

Since 1975 bar codes on products at the retail counter have been accepted as the standard for entering product identity for price determination. Since the beginning of the 21st century, the Data Matrix symbol has become accepted as the bar code format that is marked directly on a part, assembly or product that is durable enough to identify that item for its lifetime. NASA began the studies for direct part marking Data Matrix symbols on parts during the Return to Flight activities after the Challenger Accident. Over the 20 year period that has elapsed since Challenger, a mountain of studies, analyses and focused problem solutions developed by and for NASA have brought about world changing results. NASA Technical Standard 6002 and NASA Handbook 6003 for Direct Part Marking Data Matrix Symbols on Aerospace Parts have formed the basis for most other standards on part marking internationally. NASA and its commercial partners have developed numerous products and methods that addressed the difficulties of collecting part identification in aerospace operations. These products enabled the marking of Data Matrix symbols in virtually every situation and the reading of symbols at great distances, severe angles, under paint and in the dark without a light. Even unmarkable delicate parts now have a process to apply a chemical mixture, recently trademarked as Nanocodes, that can be converted to Data Matrix information through software. The accompanying intellectual property is protected by ten patents, several of which are licensed. Direct marking Data Matrix on NASA parts dramatically decreases data entry errors and the number of parts that go through their life cycle marked, two major threats to sound configuration management and flight safety. NASA is said to only have people and stuff with information connecting them. Data Matrix is one of the most significant improvements since Challenger to the safety and reliability of that connection.

NASA Technologies for Product Identification

NASA Technical Reports Server (NTRS)

Schramm, Fred, Jr.

2006-01-01

Since 1975 bar codes on products at the retail counter have been accepted as the standard for entering product identity for price determination. Since the beginning of the 21st century, the Data Matrix symbol has become accepted as the bar code format that is marked directly on a part, assembly or product that is durable enough to identify that item for its lifetime. NASA began the studies for direct part marking Data Matrix symbols on parts during the Return to Flight activities after the Challenger Accident. Over the 20 year period that has elapsed since Challenger, a mountain of studies, analyses and focused problem solutions developed by and for NASA have brought about world changing results. NASA Technical Standard 6002 and NASA Handbook 6003 for Direct Part Marking Data Matrix Symbols on Aerospace Parts have formed the basis for most other standards on part marking internationally. NASA and its commercial partners have developed numerous products and methods that addressed the difficulties of collecting part identification in aerospace operations. These products enabled the marking of Data Matrix symbols in virtually every situation and the reading of symbols at great distances, severe angles, under paint and in the dark without a light. Even unmarkable delicate parts now have a process to apply a chemical mixture called NanocodesTM that can be converted to a Data Matrix. The accompanying intellectual property is protected by 10 patents, several of which are licensed. Direct marking Data Matrix on NASA parts virtually eliminates data entry errors and the number of parts that go through their life cycle unmarked, two major threats to sound configuration management and flight safety. NASA is said to only have people and stuff with information connecting them. Data Matrix is one of the most significant improvements since Challenger to the safety and reliability of that connection. This presentation highlights the accomplishments of NASA in its efforts to develop technologies for automatic identification, its efforts to implement them and its vision on their role in space.

Capacity achieving nonbinary LDPC coded non-uniform shaping modulation for adaptive optical communications.

PubMed

Lin, Changyu; Zou, Ding; Liu, Tao; Djordjevic, Ivan B

2016-08-08

A mutual information inspired nonbinary coded modulation design with non-uniform shaping is proposed. Instead of traditional power of two signal constellation sizes, we design 5-QAM, 7-QAM and 9-QAM constellations, which can be used in adaptive optical networks. The non-uniform shaping and LDPC code rate are jointly considered in the design, which results in a better performance scheme for the same SNR values. The matched nonbinary (NB) LDPC code is used for this scheme, which further improves the coding gain and the overall performance. We analyze both coding performance and system SNR performance. We show that the proposed NB LDPC-coded 9-QAM has more than 2dB gain in symbol SNR compared to traditional LDPC-coded star-8-QAM. On the other hand, the proposed NB LDPC-coded 5-QAM and 7-QAM have even better performance than LDPC-coded QPSK.

Comparison of neurocognitive results after coronary artery bypass grafting and thoracic aortic surgery using retrograde cerebral perfusion.

PubMed

Miyairi, Takeshi; Takamoto, Shinichi; Kotsuka, Yutaka; Takeuchi, Atsuko; Yamanaka, Katsuo; Sato, Hajime

2005-07-01

Retrograde cerebral perfusion (RCP) is used as an adjunctive method to hypothermic circulatory arrest to enhance cerebral protection in patients undergoing thoracic aortic surgery. It remains unclear whether RCP provides improved neurological and neuropsychological outcome. Forty-six patients undergoing thoracic aortic surgery using RCP, and 28 undergoing coronary artery bypass grafting (CABG; n = 28) with CPB, were enrolled in the study. Patients receiving RCP were subdivided into two groups, those with less than 60 min of RCP (S-RCP; n = 27) and with 60 min or more (L-RCP; n = 19). The patients' neurocognitive state was assessed by the revised Wechsler Adult Intelligence Scale a few days before operation, at 2-3 weeks and 4-6 months after operation. There were no stroke, seizure, and hospital mortality in either group. Significant decline between baseline and early scores were seen in three subtests (digit span, arithmetic, and picture completion) for S-RCP and four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP. Significant decline between baseline and late scores were seen in one subtest (arithmetic) for S-RCP, four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP, and one (object assembly) for CABG. The mean change of scores for one late test (digit symbol) was significantly lower in S-RCP than in CABG. The mean change of scores for three early tests (digit span, vocabulary, and picture arrangement) and four late tests (information, digit span, picture completion, and picture arrangement) were significantly lower in L-RCP than in CABG. Stepwise logistic regression analysis disclosed that, after considering the other variables, significant difference in test score changes were observed between CABG and L-RCP for two early tests (picture completion and digit symbol) as well as for three late tests (digit span, similarities, and picture completion). None of test score changes showed significant difference between CABG and S-RCP. The neurocognitive outcome in patients undergoing RCP less than 60 min were comparable with patients undergoing CABG without circulatory arrest. Prolonged RCP of 60 min or more in patients undergoing surgery of the thoracic aorta was associated with postoperative neurocognitive impairment.

Pilot symbol-assisted beamforming algorithms in the WCDMA reverse link

NASA Astrophysics Data System (ADS)

Kong, Dongkeon; Lee, Jong H.; Chun, Joohwan; Woo, Yeon Sik; Soh, Ju Won

2001-08-01

We present a pilot symbol-assisted beamforming algorithm and a simulation tool of smart antennas for Wideband Code Division Multiple Access (WCDMA) in reverse link. In the 3GPP WCDMA system smart antenna technology has more room to play with than in the second generation wireless mobile systems such as IS-95 because the pilot symbol in Dedicated Physical Control Channel (DPCCH) can be utilized. First we show a smart antenna structure and adaptation algorithms, and then we explain a low-level smart antenna implementation using Simulink and MATLAB. In the design of our smart antenna system we pay special attention for the easiness of the interface to the baseband modem; Our ultimate goal is to implement a baseband smart antenna chip sets that can easily be added to to-be-existed baseband WCDMA modem units.

Dissociation between exact and approximate addition in developmental dyslexia.

PubMed

Yang, Xiujie; Meng, Xiangzhi

2016-09-01

Previous research has suggested that number sense and language are involved in number representation and calculation, in which number sense supports approximate arithmetic, and language permits exact enumeration and calculation. Meanwhile, individuals with dyslexia have a core deficit in phonological processing. Based on these findings, we thus hypothesized that children with dyslexia may exhibit exact calculation impairment while doing mental arithmetic. The reaction time and accuracy while doing exact and approximate addition with symbolic Arabic digits and non-symbolic visual arrays of dots were compared between typically developing children and children with dyslexia. Reaction time analyses did not reveal any differences across two groups of children, the accuracies, interestingly, revealed a distinction of approximation and exact addition across two groups of children. Specifically, two groups of children had no differences in approximation. Children with dyslexia, however, had significantly lower accuracy in exact addition in both symbolic and non-symbolic tasks than that of typically developing children. Moreover, linguistic performances were selectively associated with exact calculation across individuals. These results suggested that children with dyslexia have a mental arithmetic deficit specifically in the realm of exact calculation, while their approximation ability is relatively intact. Copyright © 2016 Elsevier Ltd. All rights reserved.

Number Line Estimation in Children with Developmental Dyscalculia

ERIC Educational Resources Information Center

Sella, Francesco; Berteletti, Ilaria; Martina, Brazzolotto; Lucangeli, Daniela; Zorzi, Marco

2013-01-01

In the number to position task, several studies have shown that typically developing children shift from a biased (logarithmic) to an accurate (linear) mapping of symbolic digits onto a spatial position on a line. The initial pattern of overestimation of small numbers and the underestimation of larger numbers is compensated by means of age and…

Augmenting Paper-Based Reading Activity with Direct Access to Digital Materials and Scaffolded Questioning

ERIC Educational Resources Information Center

Chen, Nian-Shing; Teng, Daniel Chia-En; Lee, Cheng-Han; Kinshuk

2011-01-01

Comprehension is the goal of reading. However, students often encounter reading difficulties due to the lack of background knowledge and proper reading strategy. Unfortunately, print text provides very limited assistance to one's reading comprehension through its static knowledge representations such as symbols, charts, and graphs. Integrating…

The Contribution of Executive Functions to Naming Digits, Objects, and Words

ERIC Educational Resources Information Center

Altani, Angeliki; Protopapas, Athanassios; Georgiou, George K.

2017-01-01

Although it is established that reading fluency is more strongly related to serial naming of symbols than to naming of isolated items ("serial superiority effect"), the reason for the difference remains unclear. The purpose of this study was to examine the role of executive functions in explaining the serial superiority effect. One…

Depressed Mood Mediates Decline in Cognitive Processing Speed in Caregivers

ERIC Educational Resources Information Center

Vitaliano, Peter P.; Zhang, Jianping; Young, Heather M.; Caswell, Lisa W.; Scanlan, James M.; Echeverria, Diana

2009-01-01

Purpose: Very few studies have examined cognitive decline in caregivers versus noncaregivers, and only 1 study has examined mediators of such decline. We evaluated the relationship between caregiver status and decline on the digit symbol test (DST; a measure of processing speed, attention, cognitive-motor translation, and visual scanning) and…

Interactive Media to Support Language Acquisition for Deaf Students

ERIC Educational Resources Information Center

Parton, Becky Sue; Hancock, Robert; Crain-Dorough, Mindy; Oescher, Jeff

2009-01-01

Tangible computing combines digital feedback with physical interactions - an important link for young children. Through the use of Radio Frequency Identification (RFID) technology, a real-world object (i.e. a chair) or a symbolic toy (i.e. a stuffed bear) can be tagged so that students can activate multimedia learning modules automatically. The…

Digitisation of Scenic and Historic Interest Areas in China

NASA Astrophysics Data System (ADS)

Yang, C.; Lawson, G.; Sim, J.

2015-08-01

Digital documents have become the major information source for heritage conservation practice. More heritage managers today use electronic maps and digital information systems to facilitate management and conservation of cultural heritage. However, the social aspects of digital heritage have not been sufficiently recognised. The aim of this paper is to examine China's `Digital Scenic Area' project, a national program started in 2004, to reveal the political and economic powers behind digital heritage practice. It was found that this project was only conducted within the most popular tourist destinations in China. Tourism information was the main object but information about landscape cultures were neglected in this project. This project also demonstrated that digital management was more like a political or economic symbol rather than a tool for heritage conservation. However, using digital technologies are still considered by the local government as a highly objective way of heritage management. Selected as a typical Scenic Area in China, Slender West Lake in Yangzhou was investigated to identify heritage stakeholder's attitudes toward digital management and the request from local management practice.

Modified-Symbol Digit Modalities Test for African Americans, Caribbean Black Americans and Non-Latino Whites: Nationally Representative Normative Data from the National Survey of American Life

PubMed Central

González, Hector M.; Whitfield, Keith E.; West, Brady T.; Williams, David R.; Lichtenberg, Peter; Jackson, James S.

2007-01-01

Normative neuropsychological data for U.S. racial/ethnic minorities is limited. Extant norms are based on small, regional groups that may not be nationally representative. The objectives of this study were to 1) provide norms for a modified Symbol Digit Modalities Test (M-SDMT) based on a nationally representative sample of African Americans, Caribbean Blacks and non-Latino Whites (NLW) living in areas with large populations of Blacks, and 2) determine significant correlates of M-SDMT performance. The M-SDMT was administered to a subset of respondents from the National Survey of American Life in standard, face-to-face interviews. M-SDMT performance was influenced by race/ethnicity, age, education, and gender. African Americans and NLW groups had similar M-SDMT performances, which differed from Caribbean Blacks. The Black ethnic differences in M-SDMT were not explained by the sociodemographic factors considered in this study. Unlike previous work, this study supports the consideration of Black ethnicity when evaluating Black neuropsychological test performance. PMID:17493782

Demonstration of digital phase-sensitive boosting to extend signal reach for long-haul WDM systems using optical phase-conjugated copy.

PubMed

Tian, Yue; Huang, Yue-Kai; Zhang, Shaoliang; Prucnal, Paul R; Wang, Ting

2013-02-25

We demonstrate a hybrid optical/digital phase-sensitive boosting (PSB) technique for long-haul wavelength division multiplexing (WDM) transmission systems. The approach uses four-wave mixing (FWM) to generate a phase-conjugated idler alongside the original signal. At the receiver, the signal and idler are jointly detected, and the phases of the idler symbols are conjugated and summed with the signal symbols to suppress noise and nonlinear phase distortion. The proposed hybrid PSB scheme is independent of modulation format and does not require an optical phase-locked loop to achieve phase matching required by conventional phase-sensitive amplifiers. Our simulation and experimental results of 112-Gb/s dual-polarization quadrature phase-shift-keying (DP-QPSK) transmission confirmed the principle of the PSB scheme, attaining a Q-factor improvement of 2.4 dB over conventional single-channel transmission after 4,800 km of dispersion-managed fiber (DMF) link at the expense of 50% reduction in spectral efficiency and extending the system reach by 60% to 7,680 km.

Power budget enhancement in NG-EPON system employing novel twisted-PAM4

NASA Astrophysics Data System (ADS)

Li, Longsheng; Bi, Meihua; Fu, Yan; Miao, Xin; Zhu, Qingming; Hu, Weisheng

2018-03-01

In this paper, we firstly design a novel modulation format named Twisted-PAM4 (T-PAM4) for the high-speed NG-EPON and the PON-based digital fronthaul system. Compared to other high-order modulation formats like 4-ary pulse amplitude modulation (PAM4), T-PAM4 provides two independent sampling values in each symbol period and enables two-dimensional symbol decision, which significantly improves the receiver sensitivity and hence enlarges the system power budget. Based on this advantage, six types of T-PAM4 are experimentally demonstrated in 28-Gb/s/ λ NG-PON and 32-Gb/s/ λ PON-based digital fronthaul system. The experimental results show that, compared to the ordinary PAM4, the T-PAM4 can bring 5-dB and 4-dB extra power budget in NG-EPON and PON-based fronthaul system respectively. In addition, by experiment, it is also depicted that the T-PAM4 is remarkably robust to system nonlinearity, which would ease the linearity requirement on system components and hence reduce system cost.

Cognitive and evoked response measures of information processing in schizophrenics with and without a family history of schizophrenia.

PubMed

Asarnow, R F; Cromwell, R L; Rennick, P M

1978-10-01

Twenty-four male schizophrenics, 12 (SFH) with schizophrenia in the immediate family and 12 (SNFH) with no evidence of schizophrenia in the family background, and 24 male control subjects, 12 highly educated (HEC), and 12 minimally educated (MEC), were assessed for premorbid social adjustment and were administered the Digit Symbol Substitution Test, a size estimation task, and the EEG average evoked response (AER) at different levels of stimulus intensity. As predicted from the stimulus redundancy formulation, the SFH patients were poorer in premorbid adjustment, were less often paranoid, functioned at a lower level of cognitive efficiency (poor digit symbol and greater absolute error on size estimation), were more chronic, and, in some respects, had size estimation indices of minimal scanning. Contrary to prediction, the SFH group had the strongest and most sustained augmenting response on AER, while the SNFH group shifted from an augmenting to a reducing pattern of response. The relationship between an absence of AER reducing and the presence of cognitive impairment in the SFH group was a major focus of discussion.

Speech coding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ravishankar, C., Hughes Network Systems, Germantown, MD

Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfullymore » regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the coding techniques are equally applicable to any voice signal whether or not it carries any intelligible information, as the term speech implies. Other terms that are commonly used are speech compression and voice compression since the fundamental idea behind speech coding is to reduce (compress) the transmission rate (or equivalently the bandwidth) And/or reduce storage requirements In this document the terms speech and voice shall be used interchangeably.« less

Readability of branding symbols in horses and histomorphological alterations at the branding site.

PubMed

Aurich, J E; Wohlsein, P; Wulf, M; Nees, M; Baumgärtner, W; Becker-Birck, M; Aurich, C

2013-03-01

Identification of horses has traditionally been facilitated by hot iron branding, but the extent by which branding symbols and numbers can be identified has not been investigated. The local pathological changes induced by branding are also unknown. This study analysed the readability of branding symbols and histomorphological alterations at the branding sites. A total of 248 horses in an equestrian championship were available for identification of symbols and numbers. A further 28 horses, euthanased for other reasons, provided histological examination of the branding site. All except one horse had evidence of histological changes at the brand site, including epidermal hyperplasia, increase of dermal collagenous fibrous tissue and loss of adnexal structures. In two foals, an ulcerative to necrotizing dermatitis was observed and interpreted as a complication of recent branding lesions. Despite the fact that hot iron branding caused lesions compatible with third degree thermal injury, it did not allow unambiguous identification of a large proportion of older horses. While the breed-specific symbol was consistently identified by three independent investigators in 84% of the horses, the double-digit branding number was read correctly by all three investigators in less than 40%. In conclusion, hot iron branding in horses causes lesions compatible with third degree thermal injury but does not always allow identification of horses. Copyright © 2012 Elsevier Ltd. All rights reserved.

Performance of Trellis Coded 256 QAM super-multicarrier modem VLSI's for SDH interface outage-free digital microwave radio

NASA Astrophysics Data System (ADS)

Aikawa, Satoru; Nakamura, Yasuhisa; Takanashi, Hitoshi

1994-02-01

This paper describes the performance of an outage free SXH (Synchronous Digital Hierarchy) interface 256 QAM modem. An outage free DMR (Digital Microwave Radio) is achieved by a high coding gain trellis coded SPORT QAM and Super Multicarrier modem. A new frame format and its associated circuits connect the outage free modem to the SDH interface. The newly designed VLSI's are key devices for developing the modem. As an overall modem performance, BER (bit error rate) characteristics and equipment signatures are presented. A coding gain of 4.7 dB (at a BER of 10(exp -4)) is obtained using SPORT 256 QAM and Viterbi decoding. This coding gain is realized by trellis coding as well as by increasing of transmission rate. Roll-off factor is decreased to maintain the same frequency occupation and modulation level as ordinary SDH 256 QAM modern.

Joint Services Electronics Program Annual Progress Report.

DTIC Science & Technology

1985-11-01

one symbol memory) adaptive lHuffman codes were performed, and the compression achieved was compared with that of Ziv - Lempel coding. As was expected...MATERIALS 8 4. Information Systems 9 4.1 REAL TIME STATISTICAL DATA PROCESSING 9 -. 4.2 DATA COMPRESSION for COMPUTER DATA STRUCTURES 9 5. PhD...a. Real Time Statistical Data Processing (T. Kailatb) b. Data Compression for Computer Data Structures (J. Gill) Acces Fo NTIS CRA&I I " DTIC TAB

Thin family: a new barcode concept

NASA Astrophysics Data System (ADS)

Allais, David C.

1991-02-01

This paper describes a new space-efficient family of thin bar code symbologies which are appropriate for representing small amounts of information. The proposed structure is 30 to 50 percent more compact than the narrowest existing bar code when 12 or fewer bits of information are to be encoded in each symbol. Potential applications for these symbologies include menus catalogs automated test and survey scoring and biological research such as the tracking of honey bees.

Coding Gains for Rank Decoding

DTIC Science & Technology

1990-02-01

PM PUB=C RERZASB DISThIDUnO UNLI M . U.S. ARMY LABORATORY COWMAND BALLISTIC RESEARCH LABORATORY ABERDEEN PROVING GROUND, MARYLAND 9o 03 is.032...Proving Ground, MD 21005-5066 ATITN: SLCBR-D Aberdeen Proving Ground, M 21005-5066 8a NAME OF FUNDING , SPONSORING 8b OFFICE SYMBOL 9 PROCUREMENT...Previouseditionsare obsolete. SECURITY CLASSIFILATION OF THIS PAGE mm m ini IIIIIIIIIIIIIII I Isn FI E Contents 1 Soft Decision Concepts 1 2 Coding Gain 2 3

Fibrinogen Recovery in Two Methods of Cryoprecipitate Preparation

DTIC Science & Technology

1989-08-01

ERNEST A. HAYGOOD, 1st Lt, USAF Executive Officer, Civilian Institution Programs 17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary...NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) 22c. OFFICE SYMBOL ERNEST A. HAYGOOD, 1st Lt, USAF (513) 255-2259 AFIT/CI DDForm...u I iv ACKNOWLEDGEMENTS I would like to extend sincerest appreciation to Dr. Lloyd Lippert , my research advisor. Without his continued guidance

Optimization of training sequence for DFT-spread DMT signal in optical access network with direct detection utilizing DML.

PubMed

Li, Fan; Li, Xinying; Yu, Jianjun; Chen, Lin

2014-09-22

We experimentally demonstrated the transmission of 79.86-Gb/s discrete-Fourier-transform spread 32 QAM discrete multi-tone (DFT-spread 32 QAM-DMT) signal over 20-km standard single-mode fiber (SSMF) utilizing directly modulated laser (DML). The experimental results show DFT-spread effectively reduces Peak-to-Average Power Ratio (PAPR) of DMT signal, and also well overcomes narrowband interference and high frequencies power attenuation. We compared different types of training sequence (TS) symbols and found that the optimized TS for channel estimation is the symbol with digital BPSK/QPSK modulation format due to its best performance against optical link noise during channel estimation.

Automated drafting system uses computer techniques

NASA Technical Reports Server (NTRS)

Millenson, D. H.

1966-01-01

Automated drafting system produces schematic and block diagrams from the design engineers freehand sketches. This system codes conventional drafting symbols and their coordinate locations on standard size drawings for entry on tapes that are used to drive a high speed photocomposition machine.

32 CFR 169a.8 - Inventory and review schedule (Report Control Symbol DD-P&L(A)).

Code of Federal Regulations, 2014 CFR

2014-07-01

... (DIA) Shall be submitted to the Assistant Secretary of Defense Production and Logistics) (ASD(P&L... to this part provides the codes and explanations for functional areas and Appendix B to this part...

32 CFR 169a.8 - Inventory and review schedule (Report Control Symbol DD-P&L(A)).

Code of Federal Regulations, 2012 CFR

2012-07-01

... (DIA) Shall be submitted to the Assistant Secretary of Defense Production and Logistics) (ASD(P&L... to this part provides the codes and explanations for functional areas and Appendix B to this part...

Role of Symbolic Coding and Rehearsal Processes in Observational Learning

ERIC Educational Resources Information Center

Bandura, Albert; Jeffery, Robert W.

1973-01-01

Results were interpreted supporting a social learning view of observational learning that emphasizes contral processing of response information in the acquisition phase and motor reproduction and incentive processes in the overt enactment of what has been learned. (Author)

The Molecular View of Plastic Deformation and Precursor Processes of Crazing in Glassy Polypropylene and Polycarbonate

DTIC Science & Technology

1991-05-31

Room 1-306 800 North Quincy Street Cambridge, MA 02139 Arlington, VA 22217 Ba NAME OF ;jNDING SPONSORING 8b OFF CE SYMBOL . 9 PROCUREMENT INSTRUMENT...Arta Code)T77=O~iE SYMBOL Dr. &enne th Wynne 1 703/696-4100 DO FORM 1473, 84 MAR 83 APR ed4,O’i ’I’y oQ used until exhaiusted SECURITY CLASSIFICATION... interactionE by means of Lennard-Jones potentials. In addition to these, the bonds between backbone atoms and their angular arrangements are considered rigid

Syndrome-source-coding and its universal generalization. [error correcting codes for data compression

NASA Technical Reports Server (NTRS)

Ancheta, T. C., Jr.

1976-01-01

A method of using error-correcting codes to obtain data compression, called syndrome-source-coding, is described in which the source sequence is treated as an error pattern whose syndrome forms the compressed data. It is shown that syndrome-source-coding can achieve arbitrarily small distortion with the number of compressed digits per source digit arbitrarily close to the entropy of a binary memoryless source. A 'universal' generalization of syndrome-source-coding is formulated which provides robustly effective distortionless coding of source ensembles. Two examples are given, comparing the performance of noiseless universal syndrome-source-coding to (1) run-length coding and (2) Lynch-Davisson-Schalkwijk-Cover universal coding for an ensemble of binary memoryless sources.

43. Cognitive Functioning in First-Episode Psychosis:_x000B_ Comparison of a 2-Year Coordinated Specialty Care Program to Community Care

PubMed Central

Schooler, Nina; Khan, Anzalee; Keefe, Richard; Robinson, Delbert; Kane, John

2017-01-01

Abstract Background: Significant cognitive impairment is already seen in first-episode psychosis (FEP) and degree of impairment is a moderator of long-term outcomes. Does specialized FEP treatment improve cognitive functioning? The NIMH sponsored RAISE-ETP study allows comparison of NAVIGATE, a coordinated specialty care intervention designed for FEP, to Community Care (CC) in a randomized clinical trial. (RCT) Methods: The RCT was conducted at 34 sites in the United States. Seventeen sites were randomly assigned to provide NAVIGATE and 17 to provide CC. Four hundred four consenting participants age 15 to 45 years old, experiencing an FEP and had not received more than 6 months of antipsychotic medication entered the study. Treatment and assessment continued for up to two years. The Brief Assessment of Cognition in Schizophrenia (BACS) was administered at baseline, one and two years. Age and sex adjusted T-scores for the BACS Composite and six sub-tests (Verbal Memory, Digit Sequencing, Verbal Fluency, Token Motor, Symbol Coding and Tower of London) were calculated. Generalized estimating equations (GEEs) were applied to compare change in treatments between baseline, months 12 and 24 adjusting for within and between site variation. Results: The NAVIGATE and CC groups included 221 and 181 participants. The Group X Visit interactions was a statistically significant predictor of change in: Verbal Memory, Verbal Fluency, Symbol Coding, Tower of London and the Composite (P < .001 for all). For the NAVIGATE group, there was significant improvement at Month 12 and Month 24 for Verbal Memory, Digit Sequencing, Tower of London, and the Composite. For the CC group, there was a significant improvement at Month 12 and Month 24 for the Composite; and only at month 24 for the Tower of London. Conclusion: The results of this analysis suggest that NAVIGATE resulted in greater improvement in cognitive functioning in both an overall score and for specific components than did CC. NAVIGATE is a multi-component intervention, guided by manuals and supervision by a central team. NAVIGATE includes psychopharmacological treatment with antipsychotics and other psychotropic medications using an internet based decision support system, an individual psychotherapy called Individual Resiliency Training, family psychoeducation and supported employment and education. The role of individual components cannot be readily determined and further analyses will evaluate the effect of moderator variables such as duration of untreated psychosis, symptomatology and functioning at study entry. To date, pharmacologic treatments to improve cognition have not demonstrated efficacy. Cognitive remediation strategies, notably Cognitive Enhancement Therapy pioneered by Gerard Hogarty, has shown efficacy in FEP patients but to the best of our knowledge, this is the first RCT to show an effect of a broad FEP focused intervention on cognitive functioning.

Coding gains and error rates from the Big Viterbi Decoder

NASA Technical Reports Server (NTRS)

Onyszchuk, I. M.

1991-01-01

A prototype hardware Big Viterbi Decoder (BVD) was completed for an experiment with the Galileo Spacecraft. Searches for new convolutional codes, studies of Viterbi decoder hardware designs and architectures, mathematical formulations, and decompositions of the deBruijn graph into identical and hierarchical subgraphs, and very large scale integration (VLSI) chip design are just a few examples of tasks completed for this project. The BVD bit error rates (BER), measured from hardware and software simulations, are plotted as a function of bit signal to noise ratio E sub b/N sub 0 on the additive white Gaussian noise channel. Using the constraint length 15, rate 1/4, experimental convolutional code for the Galileo mission, the BVD gains 1.5 dB over the NASA standard (7,1/2) Maximum Likelihood Convolution Decoder (MCD) at a BER of 0.005. At this BER, the same gain results when the (255,233) NASA standard Reed-Solomon decoder is used, which yields a word error rate of 2.1 x 10(exp -8) and a BER of 1.4 x 10(exp -9). The (15, 1/6) code to be used by the Cometary Rendezvous Asteroid Flyby (CRAF)/Cassini Missions yields 1.7 dB of coding gain. These gains are measured with respect to symbols input to the BVD and increase with decreasing BER. Also, 8-bit input symbol quantization makes the BVD resistant to demodulated signal-level variations which may cause higher bandwidth than the NASA (7,1/2) code, these gains are offset by about 0.1 dB of expected additional receiver losses. Coding gains of several decibels are possible by compressing all spacecraft data.

The applicability of WHO-NCTB in Korea.

PubMed

Kang, S K

2000-10-01

Neurotoxic chemical substances have been widely used in Korea since 1960. The World Health Organization-recommended Neurobehavioral Core Test Battery (WHO-NCTB) was introduced into Korea early in the 1990s and has been applied to the study of workers exposed to neurotoxic chemicals. Thirteen studies using the WHO-NCTB have been reported in Korean journals, two of which were published in English and the rest in Korean-language journals. Ten studies were reviewed to examine the influence of age, education and other factors on the WHO-NCTB in Korean workers. Pursuit Aiming, Digit Symbol, Digit Span and Benton Visual Retention test are effected by years of education, especially when years of education were less than 12. Santa Ana Dexterity test and Simple Reaction Time test were not effected. Pursuit Aiming, Santa Ana Dexterity test and Digit Symbol were effected by age, but not the Simple Reaction Time test, Benton Visual Retention test, or Digit Span. Some studies had difficulty in finding a proper reference group, because many workers exposed to neurotoxic chemicals were old and less educated than available reference groups. However, daily use of chopsticks by Koreans, especially coupled with work that requires skillful and quick hand movements, might develop psychomotor functions in exposed workers. The cultural and emotional differences between Korean and Caucasian led POMS to be applied only to two studies. In conclusion, the WHO-NCTB has been successfully applied to Korean workers for evaluating the neurobehavioral effects of individual chemicals, although age and education can be confounding factors. It was difficult to apply the WHO-NCTB to workers educated less than 12 years.

Development of a Tablet-based symbol digit modalities test for reliably assessing information processing speed in patients with stroke.

PubMed

Tung, Li-Chen; Yu, Wan-Hui; Lin, Gong-Hong; Yu, Tzu-Ying; Wu, Chien-Te; Tsai, Chia-Yin; Chou, Willy; Chen, Mei-Hsiang; Hsieh, Ching-Lin

2016-09-01

To develop a Tablet-based Symbol Digit Modalities Test (T-SDMT) and to examine the test-retest reliability and concurrent validity of the T-SDMT in patients with stroke. The study had two phases. In the first phase, six experts, nine college students and five outpatients participated in the development and testing of the T-SDMT. In the second phase, 52 outpatients were evaluated twice (2 weeks apart) with the T-SDMT and SDMT to examine the test-retest reliability and concurrent validity of the T-SDMT. The T-SDMT was developed via expert input and college student/patient feedback. Regarding test-retest reliability, the practise effects of the T-SDMT and SDMT were both trivial (d=0.12) but significant (p≦0.015). The improvement in the T-SDMT (4.7%) was smaller than that in the SDMT (5.6%). The minimal detectable changes (MDC%) of the T-SDMT and SDMT were 6.7 (22.8%) and 10.3 (32.8%), respectively. The T-SDMT and SDMT were highly correlated with each other at the two time points (Pearson's r=0.90-0.91). The T-SDMT demonstrated good concurrent validity with the SDMT. Because the T-SDMT had a smaller practise effect and less random measurement error (superior test-retest reliability), it is recommended over the SDMT for assessing information processing speed in patients with stroke. Implications for Rehabilitation The Symbol Digit Modalities Test (SDMT), a common measure of information processing speed, showed a substantial practise effect and considerable random measurement error in patients with stroke. The Tablet-based SDMT (T-SDMT) has been developed to reduce the practise effect and random measurement error of the SDMT in patients with stroke. The T-SDMT had smaller practise effect and random measurement error than the SDMT, which can provide more reliable assessments of information processing speed.

Associations of Nocturnal Blood Pressure With Cognition by Self-Identified Race in Middle-Aged and Older Adults: The GENOA (Genetic Epidemiology Network of Arteriopathy) Study.

PubMed

Yano, Yuichiro; Butler, Kenneth R; Hall, Michael E; Schwartz, Gary L; Knopman, David S; Lirette, Seth T; Jones, Daniel W; Wilson, James G; Hall, John E; Correa, Adolfo; Turner, Stephen T; Mosley, Thomas H

2017-10-27

Whether the association of blood pressure (BP) during sleep (nocturnal BP) with cognition differs by race is unknown. Participants in the GENOA (Genetic Epidemiology Network of Arteriopathy) Study underwent ambulatory BP measurements, brain magnetic resonance imaging, and cognitive function testing (the Rey Auditory Verbal Learning Test, the Digit Symbol Substitution Task, and the Trail Making Test Part B) between 2000 and 2007. We examined multivariable linear regression models of the nocturnal BP-cognition association. Among 755 participants (mean age, 63 years; 64% women; 42% self-identified black race; 76% taking antihypertensive medication), mean nocturnal systolic BP (SBP)/diastolic BP was 126/69 mm Hg, daytime SBP/diastolic BP level was 139/82 mm Hg, and mean reduction in SBP from day to night (dipping) was 9%. Among the entire sample, a race interaction was observed in Digit Symbol Substitution Task and Trail Making Test Part B (both P <0.15). Race-stratified analyses showed that a 1-SD increase in nocturnal SBP levels was associated with poorer Digit Symbol Substitution Task and log-transformed Trail Making Test Part B scores (unstandardized regression coefficient [95% confidence interval]: -1.98 [-3.28 to -0.69] and 0.06 [0.004-0.12]; both P< 0.05) in black but not white individuals. Additional adjustments for white matter hyperintensity volumes or brain atrophy, measured via brain magnetic resonance imaging, did not change the results. Results were similar when nocturnal SBP dipping was assessed as the exposure, yet daytime SBP levels yielded no association with cognition. Nocturnal SBP measurements may be useful in assessing the potential risk for lower cognitive function in middle-aged and older adults, particularly in black individuals. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Using Serial and Discrete Digit Naming to Unravel Word Reading Processes

PubMed Central

Altani, Angeliki; Protopapas, Athanassios; Georgiou, George K.

2018-01-01

During reading acquisition, word recognition is assumed to undergo a developmental shift from slow serial/sublexical processing of letter strings to fast parallel processing of whole word forms. This shift has been proposed to be detected by examining the size of the relationship between serial- and discrete-trial versions of word reading and rapid naming tasks. Specifically, a strong association between serial naming of symbols and single word reading suggests that words are processed serially, whereas a strong association between discrete naming of symbols and single word reading suggests that words are processed in parallel as wholes. In this study, 429 Grade 1, 3, and 5 English-speaking Canadian children were tested on serial and discrete digit naming and word reading. Across grades, single word reading was more strongly associated with discrete naming than with serial naming of digits, indicating that short high-frequency words are processed as whole units early in the development of reading ability in English. In contrast, serial naming was not a unique predictor of single word reading across grades, suggesting that within-word sequential processing was not required for the successful recognition for this set of words. Factor mixture analysis revealed that our participants could be clustered into two classes, namely beginning and more advanced readers. Serial naming uniquely predicted single word reading only among the first class of readers, indicating that novice readers rely on a serial strategy to decode words. Yet, a considerable proportion of Grade 1 students were assigned to the second class, evidently being able to process short high-frequency words as unitized symbols. We consider these findings together with those from previous studies to challenge the hypothesis of a binary distinction between serial/sublexical and parallel/lexical processing in word reading. We argue instead that sequential processing in word reading operates on a continuum, depending on the level of reading proficiency, the degree of orthographic transparency, and word-specific characteristics. PMID:29706918

Using Serial and Discrete Digit Naming to Unravel Word Reading Processes.

PubMed

Altani, Angeliki; Protopapas, Athanassios; Georgiou, George K

2018-01-01

During reading acquisition, word recognition is assumed to undergo a developmental shift from slow serial/sublexical processing of letter strings to fast parallel processing of whole word forms. This shift has been proposed to be detected by examining the size of the relationship between serial- and discrete-trial versions of word reading and rapid naming tasks. Specifically, a strong association between serial naming of symbols and single word reading suggests that words are processed serially, whereas a strong association between discrete naming of symbols and single word reading suggests that words are processed in parallel as wholes. In this study, 429 Grade 1, 3, and 5 English-speaking Canadian children were tested on serial and discrete digit naming and word reading. Across grades, single word reading was more strongly associated with discrete naming than with serial naming of digits, indicating that short high-frequency words are processed as whole units early in the development of reading ability in English. In contrast, serial naming was not a unique predictor of single word reading across grades, suggesting that within-word sequential processing was not required for the successful recognition for this set of words. Factor mixture analysis revealed that our participants could be clustered into two classes, namely beginning and more advanced readers. Serial naming uniquely predicted single word reading only among the first class of readers, indicating that novice readers rely on a serial strategy to decode words. Yet, a considerable proportion of Grade 1 students were assigned to the second class, evidently being able to process short high-frequency words as unitized symbols. We consider these findings together with those from previous studies to challenge the hypothesis of a binary distinction between serial/sublexical and parallel/lexical processing in word reading. We argue instead that sequential processing in word reading operates on a continuum, depending on the level of reading proficiency, the degree of orthographic transparency, and word-specific characteristics.

Atrial fibrillation and cognitive decline-the role of subclinical cerebral infarcts: the atherosclerosis risk in communities study.

PubMed

Chen, Lin Y; Lopez, Faye L; Gottesman, Rebecca F; Huxley, Rachel R; Agarwal, Sunil K; Loehr, Laura; Mosley, Thomas; Alonso, Alvaro

2014-09-01

The mechanism underlying the association of atrial fibrillation (AF) with cognitive decline in stroke-free individuals is unclear. We examined the association of incident AF with cognitive decline in stroke-free individuals, stratified by subclinical cerebral infarcts (SCIs) on brain MRI scans. We analyzed data from 935 stroke-free participants (mean age±SD, 61.5±4.3 years; 62% women; and 51% black) from 1993 to 1995 through 2004 to 2006 in the Atherosclerosis Risk in Communities Study, a biracial community-based prospective cohort study. Cognitive testing (including the digit symbol substitution and the word fluency tests) was performed in 1993 to 1995, 1996 to 1998, and 2004 to 2006 and brain MRI scans in 1993 to 1995 and 2004 to 2006. During follow-up, there were 48 incident AF events. Incident AF was associated with greater annual average rate of decline in digit symbol substitution (-0.77; 95% confidence interval, -1.55 to 0.01; P=0.054) and word fluency (-0.80; 95% confidence interval, -1.60 to -0.01; P=0.048). Among participants without SCIs on brain MRI scans, incident AF was not associated with cognitive decline. In contrast, incident AF was associated with greater annual average rate of decline in word fluency (-2.65; 95% confidence interval, -4.26 to -1.03; P=0.002) among participants with prevalent SCIs in 1993 to 1995. Among participants who developed SCIs during follow-up, incident AF was associated with a greater annual average rate of decline in digit symbol substitution (-1.51; 95% confidence interval, -3.02 to -0.01; P=0.049). The association of incident AF with cognitive decline in stroke-free individuals can be explained by the presence or development of SCIs, raising the possibility of anticoagulation as a strategy to prevent cognitive decline in AF. © 2014 American Heart Association, Inc.

Individual differences in the components of children's and adults' information processing for simple symbolic and non-symbolic numeric decisions.

PubMed

Thompson, Clarissa A; Ratcliff, Roger; McKoon, Gail

2016-10-01

How do speed and accuracy trade off, and what components of information processing develop as children and adults make simple numeric comparisons? Data from symbolic and non-symbolic number tasks were collected from 19 first graders (Mage=7.12 years), 26 second/third graders (Mage=8.20 years), 27 fourth/fifth graders (Mage=10.46 years), and 19 seventh/eighth graders (Mage=13.22 years). The non-symbolic task asked children to decide whether an array of asterisks had a larger or smaller number than 50, and the symbolic task asked whether a two-digit number was greater than or less than 50. We used a diffusion model analysis to estimate components of processing in tasks from accuracy, correct and error response times, and response time (RT) distributions. Participants who were accurate on one task were accurate on the other task, and participants who made fast decisions on one task made fast decisions on the other task. Older participants extracted a higher quality of information from the stimulus arrays, were more willing to make a decision, and were faster at encoding, transforming the stimulus representation, and executing their responses. Individual participants' accuracy and RTs were uncorrelated. Drift rate and boundary settings were significantly related across tasks, but they were unrelated to each other. Accuracy was mainly determined by drift rate, and RT was mainly determined by boundary separation. We concluded that RT and accuracy operate largely independently. Copyright © 2016 Elsevier Inc. All rights reserved.

What basic number processing measures in kindergarten explain unique variability in first-grade arithmetic proficiency?

PubMed

Bartelet, Dimona; Vaessen, Anniek; Blomert, Leo; Ansari, Daniel

2014-01-01

Relations between children's mathematics achievement and their basic number processing skills have been reported in both cross-sectional and longitudinal studies. Yet, some key questions are currently unresolved, including which kindergarten skills uniquely predict children's arithmetic fluency during the first year of formal schooling and the degree to which predictors are contingent on children's level of arithmetic proficiency. The current study assessed kindergarteners' non-symbolic and symbolic number processing efficiency. In addition, the contribution of children's underlying magnitude representations to differences in arithmetic achievement was assessed. Subsequently, in January of Grade 1, their arithmetic proficiency was assessed. Hierarchical regression analysis revealed that children's efficiency to compare digits, count, and estimate numerosities uniquely predicted arithmetic differences above and beyond the non-numerical factors included. Moreover, quantile regression analysis indicated that symbolic number processing efficiency was consistently a significant predictor of arithmetic achievement scores regardless of children's level of arithmetic proficiency, whereas their non-symbolic number processing efficiency was not. Finally, none of the task-specific effects indexing children's representational precision was significantly associated with arithmetic fluency. The implications of the results are 2-fold. First, the findings indicate that children's efficiency to process symbols is important for the development of their arithmetic fluency in Grade 1 above and beyond the influence of non-numerical factors. Second, the impact of children's non-symbolic number processing skills does not depend on their arithmetic achievement level given that they are selected from a nonclinical population. Copyright © 2013 Elsevier Inc. All rights reserved.

Map-invariant spectral analysis for the identification of DNA periodicities

PubMed Central

2012-01-01

Many signal processing based methods for finding hidden periodicities in DNA sequences have primarily focused on assigning numerical values to the symbolic DNA sequence and then applying spectral analysis tools such as the short-time discrete Fourier transform (ST-DFT) to locate these repeats. The key results pertaining to this approach are however obtained using a very specific symbolic to numerical map, namely the so-called Voss representation. An important research problem is to therefore quantify the sensitivity of these results to the choice of the symbolic to numerical map. In this article, a novel algebraic approach to the periodicity detection problem is presented and provides a natural framework for studying the role of the symbolic to numerical map in finding these repeats. More specifically, we derive a new matrix-based expression of the DNA spectrum that comprises most of the widely used mappings in the literature as special cases, shows that the DNA spectrum is in fact invariable under all these mappings, and generates a necessary and sufficient condition for the invariance of the DNA spectrum to the symbolic to numerical map. Furthermore, the new algebraic framework decomposes the periodicity detection problem into several fundamental building blocks that are totally independent of each other. Sophisticated digital filters and/or alternate fast data transforms such as the discrete cosine and sine transforms can therefore be always incorporated in the periodicity detection scheme regardless of the choice of the symbolic to numerical map. Although the newly proposed framework is matrix based, identification of these periodicities can be achieved at a low computational cost. PMID:23067324

Noncoherent DTTLs for Symbol Synchronization

NASA Technical Reports Server (NTRS)

Simon, Marvin; Tkacenko, Andre

2007-01-01

Noncoherent data-transition tracking loops (DTTLs) have been proposed for use as symbol synchronizers in digital communication receivers. [Communication- receiver subsystems that can perform their assigned functions in the absence of synchronization with the phases of their carrier signals ( carrier synchronization ) are denoted by the term noncoherent, while receiver subsystems that cannot function without carrier synchronization are said to be coherent. ] The proposal applies, more specifically, to receivers of binary phase-shift-keying (BPSK) signals generated by directly phase-modulating binary non-return-to-zero (NRZ) data streams onto carrier signals having known frequencies but unknown phases. The proposed noncoherent DTTLs would be modified versions of traditional DTTLs, which are coherent. The symbol-synchronization problem is essentially the problem of recovering symbol timing from a received signal. In the traditional, coherent approach to symbol synchronization, it is necessary to establish carrier synchronization in order to recover symbol timing. A traditional DTTL effects an iterative process in which it first generates an estimate of the carrier phase in the absence of symbol-synchronization information, then uses the carrier-phase estimate to obtain an estimate of the symbol-synchronization information, then feeds the symbol-synchronization estimate back to the carrier-phase-estimation subprocess. In a noncoherent symbol-synchronization process, there is no need for carrier synchronization and, hence, no need for iteration between carrier-synchronization and symbol- synchronization subprocesses. The proposed noncoherent symbolsynchronization process is justified theoretically by a mathematical derivation that starts from a maximum a posteriori (MAP) method of estimation of symbol timing utilized in traditional, coherent DTTLs. In that MAP method, one chooses the value of a variable of interest (in this case, the offset in the estimated symbol timing) that causes a likelihood function of symbol estimates over some number of symbol periods to assume a maximum value. In terms that are necessarily oversimplified to fit within the space available for this article, it can be said that the mathematical derivation involves a modified interpretation of the likelihood function that lends itself to noncoherent DTTLs. The proposal encompasses both linear and nonlinear noncoherent DTTLs. The performances of both have been computationally simulated; for comparison, the performances of linear and nonlinear coherent DTTLs have also been computationally simulated. The results of these simulations show that, among other things, the expected mean-square timing errors of coherent and noncoherent DTTLs are relatively insensitive to window width. The results also show that at high signal-to-noise ratios (SNRs), the performances of the noncoherent DTTLs approach those of their coherent counterparts at, while at low SNRs, the noncoherent DTTLs incur penalties of the order of 1.5 to 2 dB.

Intellectual system of identification of Arabic graphics

NASA Astrophysics Data System (ADS)

Abdoullayeva, Gulchin G.; Aliyev, Telman A.; Gurbanova, Nazakat G.

2001-08-01

The studies made by using the domain of graphic images allowed creating facilities of the artificial intelligence for letters, letter combinations etc. for various graphics and prints. The work proposes a system of recognition and identification of symbols of the Arabic graphics, which has its own specificity as compared to Latin and Cyrillic ones. The starting stage of the recognition and the identification is coding with further entry of information into a computer. Here the problem of entry is one of the essentials. For entry of a large volume of information in the unit of time a scanner is usually employed. Along with the scanner the authors suggest their elaboration of technical facilities for effective input and coding of the information. For refinement of symbols not identified from the scanner mostly for a small bulk of information the developed coding devices are used directly in the process of writing. The functional design of the software is elaborated on the basis of the heuristic model of the creative activity of a researcher and experts in the description and estimation of states of the weakly formalizable systems on the strength of the methods of identification and of selection of geometric features.

Rate-Compatible Protograph LDPC Codes

NASA Technical Reports Server (NTRS)

Nguyen, Thuy V. (Inventor); Nosratinia, Aria (Inventor); Divsalar, Dariush (Inventor)

2014-01-01

Digital communication coding methods resulting in rate-compatible low density parity-check (LDPC) codes built from protographs. Described digital coding methods start with a desired code rate and a selection of the numbers of variable nodes and check nodes to be used in the protograph. Constraints are set to satisfy a linear minimum distance growth property for the protograph. All possible edges in the graph are searched for the minimum iterative decoding threshold and the protograph with the lowest iterative decoding threshold is selected. Protographs designed in this manner are used in decode and forward relay channels.

Sound Symbolic Patterns in Pokémon Names.

PubMed

Kawahara, Shigeto; Noto, Atsushi; Kumagai, Gakuji

2018-04-11

This paper presents a case study of sound symbolism, cases in which certain sounds tend to be associated with particular meanings. We used the corpus of all Japanese Pokémon names available as of October 2016. We tested the effects of voiced obstruents, mora counts, and vowel quality on Pokémon characters' size, weight, strength parameters, and evolution levels. We found that the number of voiced obstruents in Pokémon names correlates positively with size, weight, evolution levels, and general strength parameters, except for speed. We argue that this result is compatible with the frequency code hypothesis of Ohala. The number of moras in Pokémon names correlates positively with size, weight, evolution levels, and all strength parameters. Vowel height is also shown to have an influence on size and weight - Pokémon characters with initial high vowels tend to be smaller and lighter, although the effect size is not very large. Not only does this paper offer a new case study of sound symbolism, it provides evidence that sound symbolism is at work when naming proper nouns. © 2018 S. Karger AG, Basel.

Apply lightweight recognition algorithms in optical music recognition

NASA Astrophysics Data System (ADS)

Pham, Viet-Khoi; Nguyen, Hai-Dang; Nguyen-Khac, Tung-Anh; Tran, Minh-Triet

2015-02-01

The problems of digitalization and transformation of musical scores into machine-readable format are necessary to be solved since they help people to enjoy music, to learn music, to conserve music sheets, and even to assist music composers. However, the results of existing methods still require improvements for higher accuracy. Therefore, the authors propose lightweight algorithms for Optical Music Recognition to help people to recognize and automatically play musical scores. In our proposal, after removing staff lines and extracting symbols, each music symbol is represented as a grid of identical M ∗ N cells, and the features are extracted and classified with multiple lightweight SVM classifiers. Through experiments, the authors find that the size of 10 ∗ 12 cells yields the highest precision value. Experimental results on the dataset consisting of 4929 music symbols taken from 18 modern music sheets in the Synthetic Score Database show that our proposed method is able to classify printed musical scores with accuracy up to 99.56%.

Representation of numerical magnitude in math-anxious individuals.

PubMed

Colomé, Àngels

2018-01-01

Larger distance effects in high math-anxious individuals (HMA) performing comparison tasks have previously been interpreted as indicating less precise magnitude representation in this population. A recent study by Dietrich, Huber, Moeller, and Klein limited the effects of math anxiety to symbolic comparison, in which they found larger distance effects for HMA, despite equivalent size effects. However, the question of whether distance effects in symbolic comparison reflect the properties of the magnitude representation or decisional processes is currently under debate. This study was designed to further explore the relation between math anxiety and magnitude representation through three different tasks. HMA and low math-anxious individuals (LMA) performed a non-symbolic comparison, in which no group differences were found. Furthermore, we did not replicate previous findings in an Arabic digit comparison, in which HMA individuals showed equivalent distance effects to their LMA peers. Lastly, there were no group differences in a counting Stroop task. Altogether, an explanation of math anxiety differences in terms of less precise magnitude representation is not supported.

Personal graphical communicator.

PubMed

Stephens, Michael; Barrett, Steven

2008-01-01

A device to help a child communicate was requested by an educator. The child cannot read, write, or speak but can recognize symbols and use those symbols to communicate. While this communication works, it doesn't work well in situations where another person does not know how to use the symbols to communicate. For this reason, a device was requested that could display images to a child and play a phrase when that image was chosen. To meet this need an MP3 player like device was constructed. The device stores images and Mpeg-Layer III (MP3) sound clips on a replaceable Secure Digital (SD) card. The images are displayed on a color Liquid Crystal Display (LCD) where the user is able to skip through images to find the phrase that needs to be said. Once found simply hitting the play button will play the sound clip associated with the image. The device is portable and compact for easy use. It uses Universal Serial Bus (USB) to recharge its batteries, communicate with the PC and update the firmware.

Modular Expression Language for Ordinary Differential Equation Editing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blake, Robert C.

MELODEEis a system for describing systems of initial value problem ordinary differential equations, and a compiler for the language that produces optimized code to integrate the differential equations. Features include rational polynomial approximation for expensive functions and automatic differentiation for symbolic jacobians

BASIC Programming.

ERIC Educational Resources Information Center

Jennings, Carol Ann

Designed for use by both secondary- and postsecondary-level business teachers, this curriculum guide consists of 10 units of instructional materials dealing with Beginners All-Purpose Symbol Instruction Code (BASIC) programing. Topics of the individual lessons are numbering BASIC programs and using the PRINT, END, and REM statements; system…

AutoBayes Program Synthesis System System Internals

NASA Technical Reports Server (NTRS)

Schumann, Johann Martin

2011-01-01

This lecture combines the theoretical background of schema based program synthesis with the hands-on study of a powerful, open-source program synthesis system (Auto-Bayes). Schema-based program synthesis is a popular approach toward program synthesis. The lecture will provide an introduction into this topic and discuss how this technology can be used to generate customized algorithms. The synthesis of advanced numerical algorithms requires the availability of a powerful symbolic (algebra) system. Its task is to symbolically solve equations, simplify expressions, or to symbolically calculate derivatives (among others) such that the synthesized algorithms become as efficient as possible. We will discuss the use and importance of the symbolic system for synthesis. Any synthesis system is a large and complex piece of code. In this lecture, we will study Autobayes in detail. AutoBayes has been developed at NASA Ames and has been made open source. It takes a compact statistical specification and generates a customized data analysis algorithm (in C/C++) from it. AutoBayes is written in SWI Prolog and many concepts from rewriting, logic, functional, and symbolic programming. We will discuss the system architecture, the schema libary and the extensive support infra-structure. Practical hands-on experiments and exercises will enable the student to get insight into a realistic program synthesis system and provides knowledge to use, modify, and extend Autobayes.

Description of the L1C signal

USGS Publications Warehouse

Betz, J.W.; Blanco, M.A.; Cahn, C.R.; Dafesh, P.A.; Hegarty, C.J.; Hudnut, K.W.; Kasemsri, V.; Keegan, R.; Kovach, K.; Lenahan, L.S.; Ma, H.H.; Rushanan, J.J.; Sklar, D.; Stansell, T.A.; Wang, C.C.; Yi, S.K.

2006-01-01

Detailed design of the modernized LI civil signal (L1C) signal has been completed, and the resulting draft Interface Specification IS-GPS-800 was released in Spring 2006. The novel characteristics of the optimized L1C signal design provide advanced capabilities while offering to receiver designers considerable flexibility in how to use these capabilities. L1C provides a number of advanced features, including: 75% of power in a pilot component for enhanced signal tracking, advanced Weilbased spreading codes, an overlay code on the pilot that provides data message synchronization, support for improved reading of clock and ephemeris by combining message symbols across messages, advanced forward error control coding, and data symbol interleaving to combat fading. The resulting design offers receiver designers the opportunity to obtain unmatched performance in many ways. This paper describes the design of L1C. A summary of LIC's background and history is provided. The signal description then proceeds with the overall signal structure consisting of a pilot component and a carrier component. The new L1C spreading code family is described, along with the logic used for generating these spreading codes. Overlay codes on the pilot channel are also described, as is the logic used for generating the overlay codes. Spreading modulation characteristics are summarized. The data message structure is also presented, showing the format for providing time, ephemeris, and system data to users, along with features that enable receivers to perform code combining. Encoding of rapidly changing time bits is described, as are the Low Density Parity Check codes used for forward error control of slowly changing time bits, clock, ephemeris, and system data. The structure of the interleaver is also presented. A summary of L 1C's unique features and their benefits is provided, along with a discussion of the plan for L1C implementation.

Super-Nyquist shaping and processing technologies for high-spectral-efficiency optical systems

NASA Astrophysics Data System (ADS)

Jia, Zhensheng; Chien, Hung-Chang; Zhang, Junwen; Dong, Ze; Cai, Yi; Yu, Jianjun

2013-12-01

The implementations of super-Nyquist pulse generation, both in a digital field using a digital-to-analog converter (DAC) or an optical filter at transmitter side, are introduced. Three corresponding signal processing algorithms at receiver are presented and compared for high spectral-efficiency (SE) optical systems employing the spectral prefiltering. Those algorithms are designed for the mitigation towards inter-symbol-interference (ISI) and inter-channel-interference (ICI) impairments by the bandwidth constraint, including 1-tap constant modulus algorithm (CMA) and 3-tap maximum likelihood sequence estimation (MLSE), regular CMA and digital filter with 2-tap MLSE, and constant multi-modulus algorithm (CMMA) with 2-tap MLSE. The principles and prefiltering tolerance are given through numerical and experimental results.

Paper-Based Textbooks with Audio Support for Print-Disabled Students.

PubMed

Fujiyoshi, Akio; Ohsawa, Akiko; Takaira, Takuya; Tani, Yoshiaki; Fujiyoshi, Mamoru; Ota, Yuko

2015-01-01

Utilizing invisible 2-dimensional codes and digital audio players with a 2-dimensional code scanner, we developed paper-based textbooks with audio support for students with print disabilities, called "multimodal textbooks." Multimodal textbooks can be read with the combination of the two modes: "reading printed text" and "listening to the speech of the text from a digital audio player with a 2-dimensional code scanner." Since multimodal textbooks look the same as regular textbooks and the price of a digital audio player is reasonable (about 30 euro), we think multimodal textbooks are suitable for students with print disabilities in ordinary classrooms.

Deductive Evaluation: Implicit Code Verification With Low User Burden

NASA Technical Reports Server (NTRS)

Di Vito, Ben L.

2016-01-01

We describe a framework for symbolically evaluating C code using a deductive approach that discovers and proves program properties. The framework applies Floyd-Hoare verification principles in its treatment of loops, with a library of iteration schemes serving to derive loop invariants. During evaluation, theorem proving is performed on-the-fly, obviating the generation of verification conditions normally needed to establish loop properties. A PVS-based prototype is presented along with results for sample C functions.

Determination of SPEAR-1 Rocket Body Potential during High-Voltage Experiments

DTIC Science & Technology

1990-06-01

California at San Diego La Jolla, CA 92093 10 . Dr. C. E. McIlwain Center for Astrophysics and Space Science University of California at San Diego La Jolla...Postgraduate School 39 Naval Postgraduate School 6c. ADDRESS (City, S:are, and ZIP Code) 7b. ADDRESS (Ciy, State, and ZIP Code) Monterey. CA 93943-5000...Monterey. CA 93943-5000 8a. NAME OF FUNDING.SPONSORING 80. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable

USAF Presence in Latin America in the 21st Century.

DTIC Science & Technology

1988-04-01

faculty in partial fulfillment of requirements for graduation. AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY MAXWELL AFB, AL 36112 UNCLASSIFIED SECURITY...ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code) Maxwell AFB AL 36112-5542 Ba. NAME OF FUNDING /SPONSORING 8 b. OFFICE SYMBOL... Servicio Multimodal Transistmico across the Isthmus of Tehuantepec (11:28). It does, however. *%4 row:n militaiy importance. The U.S. Atlantic Command’s

Mechanism of Cytotoxicity of the AIDS Virus, HTLV-III/LAV

DTIC Science & Technology

1989-05-21

distribution unlimited 4. PERFORMING OR3ANIZATION REPORT NUMBER(S) S. MONITORING ORGANIZATION REPORT NUMBER($) 143-065-3611-Al 6s. NAME OF PERFORMING... ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME Of MONITORING ORGANIZATIONj (I aI cb) Washinton University k€. ADORESS (City, State, and ZIP Code) 7b. ADDRESS...IDENTIFICATION NUMBER ORGANIZATiON U.S. Army Medical (if awible) Resch. & Development Command DArJM-17-87-C-7101 Sc. ADDRESS (Oil, State, and ZIP Code

Ffuzz: Towards full system high coverage fuzz testing on binary executables.

PubMed

Zhang, Bin; Ye, Jiaxi; Bi, Xing; Feng, Chao; Tang, Chaojing

2018-01-01

Bugs and vulnerabilities in binary executables threaten cyber security. Current discovery methods, like fuzz testing, symbolic execution and manual analysis, both have advantages and disadvantages when exercising the deeper code area in binary executables to find more bugs. In this paper, we designed and implemented a hybrid automatic bug finding tool-Ffuzz-on top of fuzz testing and selective symbolic execution. It targets full system software stack testing including both the user space and kernel space. Combining these two mainstream techniques enables us to achieve higher coverage and avoid getting stuck both in fuzz testing and symbolic execution. We also proposed two key optimizations to improve the efficiency of full system testing. We evaluated the efficiency and effectiveness of our method on real-world binary software and 844 memory corruption vulnerable programs in the Juliet test suite. The results show that Ffuzz can discover software bugs in the full system software stack effectively and efficiently.

Error correcting code with chip kill capability and power saving enhancement

DOEpatents

Gara, Alan G [Mount Kisco, NY; Chen, Dong [Croton On Husdon, NY; Coteus, Paul W [Yorktown Heights, NY; Flynn, William T [Rochester, MN; Marcella, James A [Rochester, MN; Takken, Todd [Brewster, NY; Trager, Barry M [Yorktown Heights, NY; Winograd, Shmuel [Scarsdale, NY

2011-08-30

A method and system are disclosed for detecting memory chip failure in a computer memory system. The method comprises the steps of accessing user data from a set of user data chips, and testing the user data for errors using data from a set of system data chips. This testing is done by generating a sequence of check symbols from the user data, grouping the user data into a sequence of data symbols, and computing a specified sequence of syndromes. If all the syndromes are zero, the user data has no errors. If one of the syndromes is non-zero, then a set of discriminator expressions are computed, and used to determine whether a single or double symbol error has occurred. In the preferred embodiment, less than two full system data chips are used for testing and correcting the user data.

A model-guided symbolic execution approach for network protocol implementations and vulnerability detection.

PubMed

Wen, Shameng; Meng, Qingkun; Feng, Chao; Tang, Chaojing

2017-01-01

Formal techniques have been devoted to analyzing whether network protocol specifications violate security policies; however, these methods cannot detect vulnerabilities in the implementations of the network protocols themselves. Symbolic execution can be used to analyze the paths of the network protocol implementations, but for stateful network protocols, it is difficult to reach the deep states of the protocol. This paper proposes a novel model-guided approach to detect vulnerabilities in network protocol implementations. Our method first abstracts a finite state machine (FSM) model, then utilizes the model to guide the symbolic execution. This approach achieves high coverage of both the code and the protocol states. The proposed method is implemented and applied to test numerous real-world network protocol implementations. The experimental results indicate that the proposed method is more effective than traditional fuzzing methods such as SPIKE at detecting vulnerabilities in the deep states of network protocol implementations.

High-Speed Digital Interferometry

NASA Technical Reports Server (NTRS)

De Vine, Glenn; Shaddock, Daniel A.; Ware, Brent; Spero, Robert E.; Wuchenich, Danielle M.; Klipstein, William M.; McKenzie, Kirk

2012-01-01

Digitally enhanced heterodyne interferometry (DI) is a laser metrology technique employing pseudo-random noise (PRN) codes phase-modulated onto an optical carrier. Combined with heterodyne interferometry, the PRN code is used to select individual signals, returning the inherent interferometric sensitivity determined by the optical wavelength. The signal isolation arises from the autocorrelation properties of the PRN code, enabling both rejection of spurious signals (e.g., from scattered light) and multiplexing capability using a single metrology system. The minimum separation of optical components is determined by the wavelength of the PRN code.

Digital Controller For Emergency Beacon

NASA Technical Reports Server (NTRS)

Ivancic, William D.

1990-01-01

Prototype digital controller intended for use in 406-MHz emergency beacon. Undergoing development according to international specifications, 406-MHz emergency beacon system includes satellites providing worldwide monitoring of beacons, with Doppler tracking to locate each beacon within 5 km. Controller turns beacon on and off and generates binary codes identifying source (e.g., ship, aircraft, person, or vehicle on land). Codes transmitted by phase modulation. Knowing code, monitor attempts to communicate with user, monitor uses code information to dispatch rescue team appropriate to type and locations of carrier.

Intelligibility of Digital Speech Masked by Noise: Normal Hearing and Hearing Impaired Listeners

DTIC Science & Technology

1990-06-01

spectrograms of these phrases were generated by a List 13 Processing Language (LISP) on a Symbolics 3670 artificial intelligence computer (see Figure 10). The...speech and the amount of difference varies with the type of vocoder. 26 ADPC INTELIGIBILITY AND TOE OF MAING 908 78- INTELLIGIBILITY 48 LI OS NORMA 30

Zines in the Classroom: Reading Culture

ERIC Educational Resources Information Center

Buchanan, Rebekah

2012-01-01

Gunther Kress and Theo van Leeuwen assert that language-based pedagogy is not sufficient reading in the technology-driven society. Educators need to incorporate ways for students to read other signs and symbols and redefine what it means to be literate in a digital age. Still, there are many ways in which print-based texts can be used effectively…

Integrated Spreadsheets as a Paradigm of Type II Technology Applications in Mathematics Teacher Education

ERIC Educational Resources Information Center

Abramovich, Sergei

2016-01-01

The paper presents the use of spreadsheets integrated with digital tools capable of symbolic computations and graphic constructions in a master's level capstone course for secondary mathematics teachers. Such use of spreadsheets is congruent with the Type II technology applications framework aimed at the development of conceptual knowledge in the…

e-Reading and e-Responding: New Tools for the next Generation of Readers

ERIC Educational Resources Information Center

Larson, Lotta C.

2009-01-01

Contemporary transformations in digital technologies have prompted a reassessment of what literacy means and what is determined a "text." Traditionally, text has been perceived as written messages and symbols in the forms of books, magazines, and newspapers. Today, text is recognized as much more than written words or images. As teachers consider…

Digital-computer program for design analysis of salient, wound pole alternators

NASA Technical Reports Server (NTRS)

Repas, D. S.

1973-01-01

A digital computer program for analyzing the electromagnetic design of salient, wound pole alternators is presented. The program, which is written in FORTRAN 4, calculates the open-circuit saturation curve, the field-current requirements at rated voltage for various loads and losses, efficiency, reactances, time constants, and weights. The methods used to calculate some of these items are presented or appropriate references are cited. Instructions for using the program and typical program input and output for an alternator design are given, and an alphabetical list of most FORTRAN symbols and the complete program listing with flow charts are included.

Quantized Iterative Learning Consensus Tracking of Digital Networks With Limited Information Communication.

PubMed

Xiong, Wenjun; Yu, Xinghuo; Chen, Yao; Gao, Jie

2017-06-01

This brief investigates the quantized iterative learning problem for digital networks with time-varying topologies. The information is first encoded as symbolic data and then transmitted. After the data are received, a decoder is used by the receiver to get an estimate of the sender's state. Iterative learning quantized communication is considered in the process of encoding and decoding. A sufficient condition is then presented to achieve the consensus tracking problem in a finite interval using the quantized iterative learning controllers. Finally, simulation results are given to illustrate the usefulness of the developed criterion.