Organizing for creativity, quality and speed in product creation processes

NARCIS (Netherlands)

Eijnatten, van F.M.; Simonse, W.L.

1999-01-01

Current research in industrial engineering and management sciences shows that organizational architectures are of critical importance for a better performance of product creation processes in terms of creativity, quality and speed. For many companies, streamlining those processes - including

Serial Comparison Processes and Sex Differences in Clerical Speed.

Science.gov (United States)

Majeres, Raymond L.

1988-01-01

Three experiments were conducted with 91 male and 91 female university students to assess sex differences in performance on speeded matching tests and theory on same-different judgments. Results are interpreted via the dual-process hypothesis of same-difference judgments with sex differences explained in terms of serial comparison processes rather…

White Matter Fractional Anisotropy Correlates With Speed of Processing and Motor Speed in Young Childhood Cancer Survivors

International Nuclear Information System (INIS)

Aukema, Eline J.; Caan, Matthan W.A.; Oudhuis, Nienke; Majoie, Charles; Vos, Frans M.; Reneman, Liesbeth; Last, Bob F.; Grootenhuis, Martha A.; Schouten-van Meeteren, Antoinette Y.N.

2009-01-01

Purpose: To determine whether childhood medulloblastoma and acute lymphoblastic leukemia (ALL) survivors have decreased white matter fractional anisotropy (WMFA) and whether WMFA is related to the speed of processing and motor speed. Methods and Materials: For this study, 17 patients (6 medulloblastoma, 5 ALL treated with high-dose methotrexate (MTX) (4 x 5 g/m 2 ) and 6 with low-dose MTX (3 x 2 g/m 2 )) and 17 age-matched controls participated. On a 3.0-T magnetic resonance imaging (MRI) scanner, diffusion tensor imaging (DTI) was performed, and WMFA values were calculated, including specific regions of interest (ROIs), and correlated with the speed of processing and motor speed. Results: Mean WMFA in the patient group, mean age 14 years (range 8.9 - 16.9), was decreased compared with the control group (p = 0.01), as well as WMFA in the right inferior fronto-occipital fasciliculus (IFO) (p = 0.03) and in the genu of the corpus callosum (gCC) (p = 0.01). Based on neurocognitive results, significant positive correlations were present between processing speed and WMFA in the splenium (sCC) (r = 0.53, p = 0.03) and the body of the corpus callosum (bCC) (r = 0.52, p = 0.03), whereas the right IFO WMFA was related to motor speed (r = 0.49, p < 0.05). Conclusions: White matter tracts, using a 3.0-T MRI scanner, show impairment in childhood cancer survivors, medulloblastoma survivors, and also those treated with high doses of MTX. In particular, white matter tracts in the sCC, bCC and right IFO are positively correlated with speed of processing and motor speed.

Visual Processing Speeds in Children

Directory of Open Access Journals (Sweden)

Steve Croker

2011-01-01

Full Text Available The aim of this study was to investigate visual processing speeds in children. A rapid serial visual presentation (RSVP task with schematic faces as stimuli was given to ninety-nine 6–10-year-old children as well as a short form of the WISC-III. Participants were asked to determine whether a happy face stimulus was embedded in a stream of distracter stimuli. Presentation time was gradually reduced from 500 ms per stimulus to 100 ms per stimulus, in 50 ms steps. The data revealed that (i RSVP speed increases with age, (ii children aged 8 years and over can discriminate stimuli presented every 100 ms—the speed typically used with RSVP procedures in adult and adolescent populations, and (iii RSVP speed is significantly correlated with digit span and object assembly. In consequence, the RSVP paradigm presented here is appropriate for use in further investigations of processes of temporal attention within this cohort.

Do attentional capacities and processing speed mediate the effect of age on executive functioning?

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Gilsoul, Jessica; Simon, Jessica; Hogge, Michaël; Collette, Fabienne

2018-02-06

The executive processes are well known to decline with age, and similar data also exists for attentional capacities and processing speed. Therefore, we investigated whether these two last nonexecutive variables would mediate the effect of age on executive functions (inhibition, shifting, updating, and dual-task coordination). We administered a large battery of executive, attentional and processing speed tasks to 104 young and 71 older people, and we performed mediation analyses with variables showing a significant age effect. All executive and processing speed measures showed age-related effects while only the visual scanning task performance (selective attention) was explained by age when controlled for gender and educational level. Regarding mediation analyses, visual scanning partially mediated the age effect on updating while processing speed partially mediated the age effect on shifting, updating and dual-task coordination. In a more exploratory way, inhibition was also found to partially mediate the effect of age on the three other executive functions. Attention did not greatly influence executive functioning in aging while, in agreement with the literature, processing speed seems to be a major mediator of the age effect on these processes. Interestingly, the global pattern of results seems also to indicate an influence of inhibition but further studies are needed to confirm the role of that variable as a mediator and its relative importance by comparison with processing speed.

“The Relationship between Executive Functioning, Processing Speed and White Matter Integrity in Multiple Sclerosis”

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Genova, Helen M.; DeLuca, John; Chiaravalloti, Nancy; Wylie, Glenn

2014-01-01

The primary purpose of the current study was to examine the relationship between performance on executive tasks and white matter integrity, assessed by diffusion tensor imaging (DTI) in Multiple Sclerosis (MS). A second aim was to examine how processing speed affects the relationship between executive functioning and FA. This relationship was examined in two executive tasks that rely heavily on processing speed: the Color-Word Interference Test and Trail-Making Test (Delis-Kaplan Executive Function System). It was hypothesized that reduced fractional anisotropy (FA) is related to poor performance on executive tasks in MS, but that this relationship would be affected by the statistical correction of processing speed from the executive tasks. 15 healthy controls and 25 persons with MS participated. Regression analyses were used to examine the relationship between executive functioning and FA, both before and after processing speed was removed from the executive scores. Before processing speed was removed from the executive scores, reduced FA was associated with poor performance on Color-Word Interference Test and Trail-Making Test in a diffuse network including corpus callosum and superior longitudinal fasciculus. However, once processing speed was removed, the relationship between executive functions and FA was no longer significant on the Trail Making test, and significantly reduced and more localized on the Color-Word Interference Test. PMID:23777468

Cavitation performance improvement of high specific speed mixed-flow pump

International Nuclear Information System (INIS)

Chen, T; Sun, Y B; Wu, D Z; Wang, L Q

2012-01-01

Cavitation performance improvement of large hydraulic machinery such as pump and turbine has been a hot topic for decades. During the design process of the pumps, in order to minimize size, weight and cost centrifugal and mixed-flow pump impellers are required to operate at the highest possible rotational speed. The rotational speed is limited by the phenomenon of cavitation. The hydraulic model of high-speed mixed-flow pump with large flow rate and high pumping head, which was designed based on the traditional method, always involves poor cavitation performance. In this paper, on the basis of the same hydraulic design parameters, two hydraulic models of high-speed mixed-flow pump were designed by using different methods, in order to investigate the cavitation and hydraulic performance of the two models, the method of computational fluid dynamics (CFD) was adopted for internal flow simulation of the high specific speed mixed-flow pump. Based on the results of numerical simulation, the influences of impeller parameters and three-dimensional configuration on pressure distribution of the blades' suction surfaces were analyzed. The numerical simulation results shows a better pressure distribution and lower pressure drop around the leading edge of the improved model. The research results could provide references to the design and optimization of the anti-cavitation blade.

The Puzzle of Processing Speed, Memory and Executive Function Impairments in Schizophrenia: Fitting the Pieces Together

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

2015-01-01

Background Substantial impairment in digit-symbol substitution task performance in schizophrenia is well established, which has been widely interpreted as denoting a specific impairment in processing-speed ability. However, other higher-order cognitive functions might be more critical to performance on this task. To date, this has not been rigorously investigated in schizophrenia. Methods One-hundred and twenty-five schizophrenia cases and 272 controls completed neuropsychological measures of processing speed, memory and executive functioning. We implemented a series of confirmatory factor and structural regression modeling in order to build an integrated model of processing speed, memory and executive function with which to deconstruct digit-symbol substitution task and characterize discrepancies between cases and controls. Results The overall structure of the processing speed, memory and executive function model was the same across groups (χ2 = 208.86, p>.05) but the contribution of the specific cognitive domains to coding task performance differed significantly. When completing the task controls relied on executive function and, indirectly, on working memory ability; while schizophrenia cases utilized an alternative set of cognitive operations whereby they relied on the same processes required to complete verbal fluency tasks. Conclusions Successful coding task performance is predominantly reliant on executive function, rather than processing-speed or memory abilities. Schizophrenia patients perform poorly on this task due to an apparent lack of appropriate executive function input, they rely instead on an alternative cognitive pathway. PMID:25863361

Tomography system having an ultrahigh-speed processing unit

International Nuclear Information System (INIS)

Brunnett, C.J.; Gerth, V.W. Jr.

1977-01-01

A transverse section tomography system has an ultrahigh-speed data processing unit for performing back projection and updating. An x-ray scanner directs x-ray beams through a planar section of a subject from a sequence of orientations and positions. The data processing unit includes a scan storage section for retrievably storing a set of filtered scan signals in scan storage locations corresponding to predetermined beam orientations. An array storage section is provided for storing image signals as they are generated

Tomography system having an ultrahigh speed processing unit

International Nuclear Information System (INIS)

Cox, J.P. Jr.; Gerth, V.W. Jr.

1977-01-01

A transverse section tomography system has an ultrahigh-speed data processing unit for performing back projection and updating. An x-ray scanner directs x-ray beams through a planar section of a subject from a sequence of orientations and positions. The scanner includes a movably supported radiation detector for detecting the intensity of the beams of radiation after they pass through the subject

Working memory influences processing speed and reading fluency in ADHD.

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Jacobson, Lisa A; Ryan, Matthew; Martin, Rebecca B; Ewen, Joshua; Mostofsky, Stewart H; Denckla, Martha B; Mahone, E Mark

2011-01-01

Processing-speed deficits affect reading efficiency, even among individuals who recognize and decode words accurately. Children with ADHD who decode words accurately can still have inefficient reading fluency, leading to a bottleneck in other cognitive processes. This "slowing" in ADHD is associated with deficits in fundamental components of executive function underlying processing speed, including response selection. The purpose of the present study was to deconstruct processing speed in order to determine which components of executive control best explain the "processing" speed deficits related to reading fluency in ADHD. Participants (41 ADHD, 21 controls), ages 9-14 years, screened for language disorders, word reading deficits, and psychiatric disorders, were administered measures of copying speed, processing speed, reading fluency, working memory, reaction time, inhibition, and auditory attention span. Compared to controls, children with ADHD showed reduced oral and silent reading fluency and reduced processing speed-driven primarily by deficits on WISC-IV Coding. In contrast, groups did not differ on copying speed. After controlling for copying speed, sex, severity of ADHD-related symptomatology, and GAI, slowed "processing" speed (i.e., Coding) was significantly associated with verbal span and measures of working memory but not with measures of response control/inhibition, lexical retrieval speed, reaction time, or intrasubject variability. Further, "processing" speed (i.e., Coding, residualized for copying speed) and working memory were significant predictors of oral reading fluency. Abnormalities in working memory and response selection (which are frontally mediated and enter into the output side of processing speed) may play an important role in deficits in reading fluency in ADHD, potentially more than posteriorally mediated problems with orienting of attention or perceiving the stimulus.

Directed forgetting and aging: the role of retrieval processes, processing speed, and proactive interference.

Science.gov (United States)

Hogge, Michaël; Adam, Stéphane; Collette, Fabienne

2008-07-01

The directed forgetting effect obtained with the item method is supposed to depend on both selective rehearsal of to-be-remembered (TBR) items and attentional inhibition of to-be-forgotten (TBF) items. In this study, we investigated the locus of the directed forgetting deficit in older adults by exploring the influence of recollection and familiarity-based retrieval processes on age-related differences in directed forgetting. Moreover, we explored the influence of processing speed, short-term memory capacity, thought suppression tendencies, and sensitivity to proactive interference on performance. The results indicated that older adults' directed forgetting difficulties are due to decreased recollection of TBR items, associated with increased automatic retrieval of TBF items. Moreover, processing speed and proactive interference appeared to be responsible for the decreased recall of TBR items.

Intra-individual variability in information processing speed reflects white matter microstructure in multiple sclerosis.

Science.gov (United States)

Mazerolle, Erin L; Wojtowicz, Magdalena A; Omisade, Antonina; Fisk, John D

2013-01-01

Slowed information processing speed is commonly reported in persons with multiple sclerosis (MS), and is typically investigated using clinical neuropsychological tests, which provide sensitive indices of mean-level information processing speed. However, recent studies have demonstrated that within-person variability or intra-individual variability (IIV) in information processing speed may be a more sensitive indicator of neurologic status than mean-level performance on clinical tests. We evaluated the neural basis of increased IIV in mildly affected relapsing-remitting MS patients by characterizing the relation between IIV (controlling for mean-level performance) and white matter integrity using diffusion tensor imaging (DTI). Twenty women with relapsing-remitting MS and 20 matched control participants completed the Computerized Test of Information Processing (CTIP), from which both mean response time and IIV were calculated. Other clinical measures of information processing speed were also collected. Relations between IIV on the CTIP and DTI metrics of white matter microstructure were evaluated using tract-based spatial statistics. We observed slower and more variable responses on the CTIP in MS patients relative to controls. Significant relations between white matter microstructure and IIV were observed for MS patients. Increased IIV was associated with reduced integrity in more white matter tracts than was slowed information processing speed as measured by either mean CTIP response time or other neuropsychological test scores. Thus, despite the common use of mean-level performance as an index of cognitive dysfunction in MS, IIV may be more sensitive to the overall burden of white matter disease at the microstructural level. Furthermore, our study highlights the potential value of considering within-person fluctuations, in addition to mean-level performance, for uncovering brain-behavior relationships in neurologic disorders with widespread white matter pathology.

Study on transient hydrodynamic performance and cavitation characteristic of high-speed mixed-flow pump

International Nuclear Information System (INIS)

Chen, T; Liu, Y L; Sun, Y B; Wang, L Q; Wu, D Z

2013-01-01

In order to analyse the hydrodynamic performance and cavitation characteristic of a high-speed mixed-flow pump during transient operations, experimental studies were carried out. The transient hydrodynamic performance and cavitation characteristics of the mixed-flow pump with guide vane during start-up operation processes were tested on the pump performance test-bed. Performance tests of the pump were carried out under various inlet pressures and speed-changing operations. The real-time instantaneous external characteristics such as rotational speed, hydraulic head, flow rate, suction pressure and discharge pressure of the pump were measured. Based on the experimental results, the effect of fluid acceleration on the hydrodynamic performances and cavitation characteristics of the mixed-flow pump were analysed and evaluated

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

Science.gov (United States)

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.

Age Differences in Text Processing: The Role of Working Memory, Inhibition, and Processing Speed

OpenAIRE

BORELLA ERIKA; GHISLETTA PAOLO; DE RIBAUPIERRE ANIK

2011-01-01

Objectives. Age-related changes in the efficiency of various general cognitive mechanisms have been evoked to account for age-related differences between young and older adults in text comprehension performance. Using structural equation modeling, we investigate the relationship between age, working memory (WM), inhibition-related mechanisms, processing speed, and text comprehension, focusing on surface and text-based levels of processing. Methods. Eighty-nine younger (M = 23.11 years) and 10...

Neonatal Brain Pathology Predicts Adverse Attention and Processing Speed Outcomes in Very Preterm and/or Very Low Birth Weight Children

Science.gov (United States)

Murray, Andrea L; Scratch, Shannon E; Thompson, Deanne K; Inder, Terrie E; Doyle, Lex W; Anderson, Jacqueline F. I.; Anderson, Peter J

2014-01-01

Objective This study aimed to examine attention and processing speed outcomes in very preterm (VPT; deep gray matter, and cerebellar abnormalities. Attention and processing speed were assessed at 7 years using standardized neuropsychological tests. Group differences were tested in attention and processing speed, and the relationships between these cognitive domains and brain abnormalities at birth were investigated. Results At 7 years of age, the VPT/VLBW group performed significantly poorer than term controls on all attention and processing speed outcomes. Associations between adverse attention and processing speed performances at 7 years and higher neonatal brain abnormality scores were found; in particular, white matter and deep gray matter abnormalities were reasonable predictors of long-term cognitive outcomes. Conclusion Attention and processing speed are significant areas of concern in VPT/VLBW children. This is the first study to show that adverse attention and processing speed outcomes at 7 years are associated with neonatal brain pathology. PMID:24708047

[Information processing speed and influential factors in multiple sclerosis].

Science.gov (United States)

Zhang, M L; Xu, E H; Dong, H Q; Zhang, J W

2016-04-19

To study the information processing speed and the influential factors in multiple sclerosis (MS) patients. A total of 36 patients with relapsing-remitting MS (RRMS), 21 patients with secondary progressive MS (SPMS), and 50 healthy control subjects from Xuanwu Hospital of Capital Medical University between April 2010 and April 2012 were included into this cross-sectional study.Neuropsychological tests was conducted after the disease had been stable for 8 weeks, including information processing speed, memory, executive functions, language and visual perception.Correlation between information processing speed and depression, fatigue, Expanded Disability Status Scale (EDSS) were studied. (1)MS patient groups demonstrated cognitive deficits compared to healthy controls.The Symbol Digit Modalities Test (SDMT) (control group 57±12; RRMS group 46±17; SPMS group 35±10, Pinformation processing (Pinformation processing speed, verbal memory and executive functioning are seen in MS patients, especially in SPMS subtype, while visual-spatial function is relatively reserved.Age, white matter change scales, EDSS scores, depression are negatively associated with information processing speed.

Relative speed of processing determines color-word contingency learning.

Science.gov (United States)

Forrin, Noah D; MacLeod, Colin M

2017-10-01

In three experiments, we tested a relative-speed-of-processing account of color-word contingency learning, a phenomenon in which color identification responses to high-contingency stimuli (words that appear most often in particular colors) are faster than those to low-contingency stimuli. Experiment 1 showed equally large contingency-learning effects whether responding was to the colors or to the words, likely due to slow responding to both dimensions because of the unfamiliar mapping required by the key press responses. For Experiment 2, participants switched to vocal responding, in which reading words is considerably faster than naming colors, and we obtained a contingency-learning effect only for color naming, the slower dimension. In Experiment 3, previewing the color information resulted in a reduced contingency-learning effect for color naming, but it enhanced the contingency-learning effect for word reading. These results are all consistent with contingency learning influencing performance only when the nominally irrelevant feature is faster to process than the relevant feature, and therefore are entirely in accord with a relative-speed-of-processing explanation.

Cultural Differences in the Development of Processing Speed

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Kail, Robert V.; McBride-Chang, Catherine; Ferrer, Emilio; Cho, Jeung-Ryeul; Shu, Hua

2013-01-01

The aim of the present work was to examine cultural differences in the development of speed of information processing. Four samples of US children ("N" = 509) and four samples of East Asian children ("N" = 661) completed psychometric measures of processing speed on two occasions. Analyses of the longitudinal data indicated…

Development of time sensitivity and information processing speed.

Directory of Open Access Journals (Sweden)

Sylvie Droit-Volet

Full Text Available The aim of this study was to examine whether age-related changes in the speed of information processing are the best predictors of the increase in sensitivity to time throughout childhood. Children aged 5 and 8 years old, as well adults, were given two temporal bisection tasks, one with short (0.5/1-s and the other with longer (4/8-s anchor durations. In addition, the participants' scores on different neuropsychological tests assessing both information processing speed and other dimensions of cognitive control (short-term memory, working memory, selective attention were calculated. The results showed that the best predictor of individual variances in sensitivity to time was information processing speed, although working memory also accounted for some of the individual differences in time sensitivity, albeit to a lesser extent. In sum, the faster the information processing speed of the participants, the higher their sensitivity to time was. These results are discussed in the light of the idea that the development of temporal capacities has its roots in the maturation of the dynamic functioning of the brain.

Cutting force model for high speed machining process

International Nuclear Information System (INIS)

Haber, R. E.; Jimenez, J. E.; Jimenez, A.; Lopez-Coronado, J.

2004-01-01

This paper presents cutting force-based models able to describe a high speed machining process. The model considers the cutting force as output variable, essential for the physical processes that are taking place in high speed machining. Moreover, this paper shows the mathematical development to derive the integral-differential equations, and the algorithms implemented in MATLAB to predict the cutting force in real time MATLAB is a software tool for doing numerical computations with matrices and vectors. It can also display information graphically and includes many toolboxes for several research and applications areas. Two end mill shapes are considered (i. e. cylindrical and ball end mill) for real-time implementation of the developed algorithms. the developed models are validated in slot milling operations. The results corroborate the importance of the cutting force variable for predicting tool wear in high speed machining operations. The developed models are the starting point for future work related with vibration analysis, process stability and dimensional surface finish in high speed machining processes. (Author) 19 refs

Effects of chewing on cognitive processing speed.

Science.gov (United States)

Hirano, Yoshiyuki; Obata, Takayuki; Takahashi, Hidehiko; Tachibana, Atsumichi; Kuroiwa, Daigo; Takahashi, Toru; Ikehira, Hiroo; Onozuka, Minoru

2013-04-01

In recent years, chewing has been discussed as producing effects of maintaining and sustaining cognitive performance. We have reported that chewing may improve or recover the process of working memory; however, the mechanisms underlying these phenomena are still to be elucidated. We investigated the effect of chewing on aspects of attention and cognitive processing speed, testing the hypothesis that this effect induces higher cognitive performance. Seventeen healthy adults (20-34 years old) were studied during attention task with blood oxygenation level-dependent functional (fMRI) at 3.0 T MRI. The attentional network test (ANT) within a single task fMRI containing two cue conditions (no cue and center cue) and two target conditions (congruent and incongruent) was conducted to examine the efficiency of alerting and executive control. Participants were instructed to press a button with the right or left thumb according to the direction of a centrally presented arrow. Each participant underwent two back-to-back ANT sessions with or without chewing gum, odorless and tasteless to remove any effect other than chewing. Behavioral results showed that mean reaction time was significantly decreased during chewing condition, regardless of speed-accuracy trade-off, although there were no significant changes in behavioral effects (both alerting and conflict effects). On the other hand, fMRI analysis revealed higher activations in the anterior cingulate cortex and left frontal gyrus for the executive network and motor-related regions for both attentional networks during chewing condition. These results suggested that chewing induced an increase in the arousal level and alertness in addition to an effect on motor control and, as a consequence, these effects could lead to improvements in cognitive performance. Published by Elsevier Inc.

Speed and lateral inhibition of stimulus processing contribute to individual differences in Stroop-task performance

Directory of Open Access Journals (Sweden)

Marnix eNaber

2016-06-01

Full Text Available The Stroop task is a popular neuropsychological test that measures executive control. Strong Stroop interference is commonly interpreted in neuropsychology as a diagnostic marker of an impairment in executive control, possibly reflecting executive dysfunction. However, popular models of the Stroop task indicate that several other aspects of colour and word processing may also account for individual differences in the Stroop task, independent of executive control. Here we use new approaches to investigate the degree to which individual differences in Stroop interference correlate with the relative processing speed of word and colour stimuli, and the lateral inhibition between visual stimuli. We conducted an electrophysiological and behavioural experiment to measure (1 how quickly an individual’s brain processes words and colours presented in isolation (P3 latency, and (2 the strength of an individual’s lateral inhibition between visual representations with a visual illusion. Both measures explained at least 40% of the variance in Stroop interference across individuals. As these measures were obtained in contexts not requiring any executive control, we conclude that the Stroop effect also measures an individual’s pre-set way of processing visual features such as words and colours. This study highlights the important contributions of stimulus processing speed and lateral inhibition to individual differences in Stroop interference, and challenges the general view that the Stroop task primarily assesses executive control.

Speed and Lateral Inhibition of Stimulus Processing Contribute to Individual Differences in Stroop-Task Performance.

Science.gov (United States)

Naber, Marnix; Vedder, Anneke; Brown, Stephen B R E; Nieuwenhuis, Sander

2016-01-01

The Stroop task is a popular neuropsychological test that measures executive control. Strong Stroop interference is commonly interpreted in neuropsychology as a diagnostic marker of impairment in executive control, possibly reflecting executive dysfunction. However, popular models of the Stroop task indicate that several other aspects of color and word processing may also account for individual differences in the Stroop task, independent of executive control. Here we use new approaches to investigate the degree to which individual differences in Stroop interference correlate with the relative processing speed of word and color stimuli, and the lateral inhibition between visual stimuli. We conducted an electrophysiological and behavioral experiment to measure (1) how quickly an individual's brain processes words and colors presented in isolation (P3 latency), and (2) the strength of an individual's lateral inhibition between visual representations with a visual illusion. Both measures explained at least 40% of the variance in Stroop interference across individuals. As these measures were obtained in contexts not requiring any executive control, we conclude that the Stroop effect also measures an individual's pre-set way of processing visual features such as words and colors. This study highlights the important contributions of stimulus processing speed and lateral inhibition to individual differences in Stroop interference, and challenges the general view that the Stroop task primarily assesses executive control.

Color improves speed of processing but not perception in a motion illusion

Directory of Open Access Journals (Sweden)

Carolyn J Perry

2012-03-01

Full Text Available When two superimposed surfaces of dots move in different directions, the perceived directions are shifted away from each other. This perceptual illusion has been termed direction repulsion and is thought to be due to mutual inhibition between the representations of the two directions. It has further been shown that a speed difference between the two surfaces attenuates direction repulsion. As speed and direction are both necessary components of representing motion, the reduction in direction repulsion can be attributed to the additional motion information strengthening the representations of the two directions and thus reducing the mutual inhibition. We tested whether bottom-up attention and top-down task demands, in the form of color differences between the two surfaces, would also enhance motion processing, reducing direction repulsion. We found that the addition of color differences did not improve direction discrimination and reduce direction repulsion. However, we did find that adding a color difference improved performance on the task. We hypothesized that the performance differences were due to the limited presentation time of the stimuli. We tested this in a follow-up experiment where we varied the time of presentation to determine the duration needed to successfully perform the task with and without the color difference. As we expected, the addition of color reduced the amount of time needed to process and encode both directions of motion. Thus we find a dissociation between the effects of attention on the speed of processing and conscious perception. We propose 4 potential mechanisms wherein color speeds figure-ground segmentation of an object, attentional switching between objects, direction discrimination and/or the accumulation of motion information for decision-making, without affecting conscious perception. Potential neural bases are also explored.

Color improves speed of processing but not perception in a motion illusion.

Science.gov (United States)

Perry, Carolyn J; Fallah, Mazyar

2012-01-01

When two superimposed surfaces of dots move in different directions, the perceived directions are shifted away from each other. This perceptual illusion has been termed direction repulsion and is thought to be due to mutual inhibition between the representations of the two directions. It has further been shown that a speed difference between the two surfaces attenuates direction repulsion. As speed and direction are both necessary components of representing motion, the reduction in direction repulsion can be attributed to the additional motion information strengthening the representations of the two directions and thus reducing the mutual inhibition. We tested whether bottom-up attention and top-down task demands, in the form of color differences between the two surfaces, would also enhance motion processing, reducing direction repulsion. We found that the addition of color differences did not improve direction discrimination and reduce direction repulsion. However, we did find that adding a color difference improved performance on the task. We hypothesized that the performance differences were due to the limited presentation time of the stimuli. We tested this in a follow-up experiment where we varied the time of presentation to determine the duration needed to successfully perform the task with and without the color difference. As we expected, color segmentation reduced the amount of time needed to process and encode both directions of motion. Thus we find a dissociation between the effects of attention on the speed of processing and conscious perception of direction. We propose four potential mechanisms wherein color speeds figure-ground segmentation of an object, attentional switching between objects, direction discrimination and/or the accumulation of motion information for decision-making, without affecting conscious perception of the direction. Potential neural bases are also explored.

Delineating psychomotor slowing from reduced processing speed in schizophrenia

NARCIS (Netherlands)

Morrens, M.; Hulstijn, W.; Matton, C.; Madani, Y.; Bouwel, L. van; Peuskens, J.; Sabbe, B.G.C.

2008-01-01

Introduction. Psychomotor slowing is an intrinsic feature of schizophrenia that is poorly delineated from generally reduced processing speed. Although the Symbol Digit Substitution Test (SDST) is widely used to assess psychomotor speed, the task also taps several higher-order cognitive processes.

Economic performance indicators of wind energy based on wind speed stochastic modeling

International Nuclear Information System (INIS)

D’Amico, Guglielmo; Petroni, Filippo; Prattico, Flavio

2015-01-01

Highlights: • We propose a new and different wind energy production indicator. • We compute financial profitability of potential wind power sites. • The wind speed process is modeled as an indexed semi-Markov chain. • We check if the wind energy is a good investment with and without incentives. - Abstract: We propose the computation of different wind energy production indicators and financial profitability of potential wind power sites. The computation is performed by modeling the wind speed process as an indexed semi-Markov chain to predict and simulate the wind speed dynamics. We demonstrate that the indexed semi-Markov chain approach enables reproducing the indicators calculated on real data. Two different time horizons of 15 and 30 years are analyzed. In the first case we consider the government incentives on the energy price now present in Italy, while in the second case the incentives have not been taken into account

High-speed optical coherence tomography signal processing on GPU

International Nuclear Information System (INIS)

Li Xiqi; Shi Guohua; Zhang Yudong

2011-01-01

The signal processing speed of spectral domain optical coherence tomography (SD-OCT) has become a bottleneck in many medical applications. Recently, a time-domain interpolation method was proposed. This method not only gets a better signal-to noise ratio (SNR) but also gets a faster signal processing time for the SD-OCT than the widely used zero-padding interpolation method. Furthermore, the re-sampled data is obtained by convoluting the acquired data and the coefficients in time domain. Thus, a lot of interpolations can be performed concurrently. So, this interpolation method is suitable for parallel computing. An ultra-high optical coherence tomography signal processing can be realized by using graphics processing unit (GPU) with computer unified device architecture (CUDA). This paper will introduce the signal processing steps of SD-OCT on GPU. An experiment is performed to acquire a frame SD-OCT data (400A-linesx2048 pixel per A-line) and real-time processed the data on GPU. The results show that it can be finished in 6.208 milliseconds, which is 37 times faster than that on Central Processing Unit (CPU).

Episodic and semantic memory functioning in very old age: Explanations from executive functioning and processing speed theories

Directory of Open Access Journals (Sweden)

Pauline E.J. Spaan

2015-12-01

Full Text Available Structural equation modeling was used to investigate whether age-related episodic and semantic memory impairments are better explained by decline in processing speed or executive functioning (or both, rather than directly in terms of memory components. The models tested were based on an extensive review of the literature on cognitive decline in normal aging, up to very old age. A computerized test battery, measuring episodic memory (free and cued recall; recognition, semantic memory (fluency; naming accuracy and latencies, processing speed and executive functioning, was administered to 234 elderly persons ranging from young-old to very old age (55–96 years. To avoid large variance in response times due to physical instead of cognitive limitations, no motor responses were required from participants. Age-related decline in episodic and semantic memory performance was found to be the consequence of declines in processing speed and executive functioning. Processing speed mainly mediated decline of semantic memory, whereas executive functioning mainly mediated episodic memory decline. The most parsimonious model showed that both processing speed and executive functioning attributed to memory decline but independent from one another. The results suggest that at very old age, the impact of executive dysfunctions on episodic memory performance exceeds the influence of cognitive slowing.

Neural dynamics of motion processing and speed discrimination.

Science.gov (United States)

Chey, J; Grossberg, S; Mingolla, E

1998-09-01

A neural network model of visual motion perception and speed discrimination is presented. The model shows how a distributed population code of speed tuning, that realizes a size-speed correlation, can be derived from the simplest mechanisms whereby activations of multiple spatially short-range filters of different size are transformed into speed-turned cell responses. These mechanisms use transient cell responses to moving stimuli, output thresholds that covary with filter size, and competition. These mechanisms are proposed to occur in the V1-->MT cortical processing stream. The model reproduces empirically derived speed discrimination curves and simulates data showing how visual speed perception and discrimination can be affected by stimulus contrast, duration, dot density and spatial frequency. Model motion mechanisms are analogous to mechanisms that have been used to model 3-D form and figure-ground perception. The model forms the front end of a larger motion processing system that has been used to simulate how global motion capture occurs, and how spatial attention is drawn to moving forms. It provides a computational foundation for an emerging neural theory of 3-D form and motion perception.

The relative contributions of processing speed and cognitive load to working memory accuracy in multiple sclerosis.

Science.gov (United States)

Leavitt, Victoria M; Lengenfelder, Jean; Moore, Nancy B; Chiaravalloti, Nancy D; DeLuca, John

2011-06-01

Cognitive symptoms of multiple sclerosis (MS) include processing-speed deficits and working memory impairment. The precise manner in which these deficits interact in individuals with MS remains to be explicated. We hypothesized that providing more time on a complex working memory task would result in performance benefits for individuals with MS relative to healthy controls. Fifty-three individuals with clinically definite MS and 36 matched healthy controls performed a computerized task that systematically manipulated cognitive load. The interval between stimuli presentations was manipulated to provide increasing processing time. The results confirmed that individuals with MS who have processing-speed deficits significantly improve in performance accuracy when given additional time to process the information in working memory. Implications of these findings for developing appropriate cognitive rehabilitation interventions are discussed.

Towards real-time feedback in high performance speed skating

NARCIS (Netherlands)

van der Eb, Jeroen; Zandee, Willem; van den Bogaard, Timo; Geraets, Sjoerd; Veeger, H.E.J.; Beek, Peter; Potthast, Wolfgang; Niehoff, Anja; David, Sina

2017-01-01

The aim of the current study is to evaluate several performance indicators to be used as real-time feedback in the coming experiments to enhance performance of elite speeds skaters. Six speed skaters, wearing one IMU per skate, collected data over one full training season to evaluate and pinpoint

Reading component skills in dyslexia: word recognition, comprehension and processing speed.

Science.gov (United States)

de Oliveira, Darlene G; da Silva, Patrícia B; Dias, Natália M; Seabra, Alessandra G; Macedo, Elizeu C

2014-01-01

The cognitive model of reading comprehension (RC) posits that RC is a result of the interaction between decoding and linguistic comprehension. Recently, the notion of decoding skill was expanded to include word recognition. In addition, some studies suggest that other skills could be integrated into this model, like processing speed, and have consistently indicated that this skill influences and is an important predictor of the main components of the model, such as vocabulary for comprehension and phonological awareness of word recognition. The following study evaluated the components of the RC model and predictive skills in children and adolescents with dyslexia. 40 children and adolescents (8-13 years) were divided in a Dyslexic Group (DG; 18 children, MA = 10.78, SD = 1.66) and control group (CG 22 children, MA = 10.59, SD = 1.86). All were students from the 2nd to 8th grade of elementary school and groups were equivalent in school grade, age, gender, and IQ. Oral and RC, word recognition, processing speed, picture naming, receptive vocabulary, and phonological awareness were assessed. There were no group differences regarding the accuracy in oral and RC, phonological awareness, naming, and vocabulary scores. DG performed worse than the CG in word recognition (general score and orthographic confusion items) and were slower in naming. Results corroborated the literature regarding word recognition and processing speed deficits in dyslexia. However, dyslexics can achieve normal scores on RC test. Data supports the importance of delimitation of different reading strategies embedded in the word recognition component. The role of processing speed in reading problems remain unclear.

Increased prolactin levels are associated with impaired processing speed in subjects with early psychosis.

Directory of Open Access Journals (Sweden)

Itziar Montalvo

Full Text Available Hyperprolactinaemia, a common side effect of some antipsychotic drugs, is also present in drug-naïve psychotic patients and subjects at risk for psychosis. Recent studies in non-psychiatric populations suggest that increased prolactin may have negative effects on cognition. The aim of our study was to explore whether high plasma prolactin levels are associated with poorer cognitive functioning in subjects with early psychoses. We studied 107 participants: 29 healthy subjects and 78 subjects with an early psychosis (55 psychotic disorders with <3 years of illness, 23 high-risk subjects. Cognitive assessment was performed with the MATRICS Cognitive Consensus Cognitive Battery, and prolactin levels were determined as well as total cortisol levels in plasma. Psychopathological status was assessed and the use of psychopharmacological treatments (antipsychotics, antidepressants, benzodiazepines recorded. Prolactin levels were negatively associated with cognitive performance in processing speed, in patients with a psychotic disorder and high-risk subjects. In the latter group, increased prolactin levels were also associated with impaired reasoning and problem solving and poorer general cognition. In a multiple linear regression analysis conducted in both high-risk and psychotic patients, controlling for potential confounders, prolactin and benzodiazepines were independently related to poorer cognitive performance in the speed of processing domain. A mediation analysis showed that both prolactin and benzodiazepine treatment act as mediators of the relationship between risperidone/paliperidone treatment and speed of processing. These results suggest that increased prolactin levels are associated with impaired processing speed in early psychosis. If these results are confirmed in future studies, strategies targeting reduction of prolactin levels may improve cognition in this population.

Increased prolactin levels are associated with impaired processing speed in subjects with early psychosis.

Science.gov (United States)

Montalvo, Itziar; Gutiérrez-Zotes, Alfonso; Creus, Marta; Monseny, Rosa; Ortega, Laura; Franch, Joan; Lawrie, Stephen M; Reynolds, Rebecca M; Vilella, Elisabet; Labad, Javier

2014-01-01

Hyperprolactinaemia, a common side effect of some antipsychotic drugs, is also present in drug-naïve psychotic patients and subjects at risk for psychosis. Recent studies in non-psychiatric populations suggest that increased prolactin may have negative effects on cognition. The aim of our study was to explore whether high plasma prolactin levels are associated with poorer cognitive functioning in subjects with early psychoses. We studied 107 participants: 29 healthy subjects and 78 subjects with an early psychosis (55 psychotic disorders with levels were determined as well as total cortisol levels in plasma. Psychopathological status was assessed and the use of psychopharmacological treatments (antipsychotics, antidepressants, benzodiazepines) recorded. Prolactin levels were negatively associated with cognitive performance in processing speed, in patients with a psychotic disorder and high-risk subjects. In the latter group, increased prolactin levels were also associated with impaired reasoning and problem solving and poorer general cognition. In a multiple linear regression analysis conducted in both high-risk and psychotic patients, controlling for potential confounders, prolactin and benzodiazepines were independently related to poorer cognitive performance in the speed of processing domain. A mediation analysis showed that both prolactin and benzodiazepine treatment act as mediators of the relationship between risperidone/paliperidone treatment and speed of processing. These results suggest that increased prolactin levels are associated with impaired processing speed in early psychosis. If these results are confirmed in future studies, strategies targeting reduction of prolactin levels may improve cognition in this population.

High-speed optical signal processing using time lenses

DEFF Research Database (Denmark)

Galili, Michael; Hu, Hao; Guan, Pengyu

2015-01-01

This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

Predictors of Memory and Processing Speed Dysfunctions after Traumatic Brain Injury

Directory of Open Access Journals (Sweden)

William Winardi

2014-01-01

Full Text Available Background. The aims of this study were to evaluate the predictive value of admission Glasgow Coma Scale (GCS scores, duration of unconsciousness, neurosurgical intervention, and countercoup lesion on the impairment of memory and processing speed functions six months after a traumatic brain injury (TBI based on a structural equation modeling. Methods. Thirty TBI patients recruited from Neurosurgical Department at the Kaohsiung Medical University Hospital were administered the Wechsler Memory Scale-III (WMS-III and the Wechsler Adult Intelligence Scale-III processing speed index to evaluate the memory and processing speed functions. Results. The study showed that GCS scores accounted for 40% of the variance in memory/processing speed. No significant predictive effects were found for the other three variables. GCS classification at the time of TBI seems to correspond moderately to the severity of memory/processing speed dysfunctions. Conclusions. The present study demonstrated that admission GCS score is a robust predictor of memory/processing speed dysfunctions after TBI. The results should be replicated with a large sample of patients with TBI, or be extended by examining other potential clinical predictors.

Design of FPGA based high-speed data acquisition and real-time data processing system on J-TEXT tokamak

International Nuclear Information System (INIS)

Zheng, W.; Liu, R.; Zhang, M.; Zhuang, G.; Yuan, T.

2014-01-01

Highlights: • It is a data acquisition system for polarimeter–interferometer diagnostic on J-TEXT tokamak based on FPGA and PXIe devices. • The system provides a powerful data acquisition and real-time data processing performance. • Users can implement different data processing applications on the FPGA in a short time. • This system supports EPICS and has been integrated into the J-TEXT CODAC system. - Abstract: Tokamak experiment requires high-speed data acquisition and processing systems. In traditional data acquisition system, the sampling rate, channel numbers and processing speed are limited by bus throughput and CPU speed. This paper presents a data acquisition and processing system based on FPGA. The data can be processed in real-time before it is passed to the CPU. It provides processing ability for more channels with higher sampling rates than the traditional data acquisition system while ensuring deterministic real-time performance. A working prototype is developed for the newly built polarimeter–interferometer diagnostic system on the Joint Texas Experimental Tokamak (J-TEXT). It provides 16 channels with 120 MHz maximum sampling rate and 16 bit resolution. The onboard FPGA is able to calculate the plasma electron density and Faraday rotation angel. A RAID 5 storage device is adopted providing 700 MB/s read–write speed to buffer the data to the hard disk continuously for better performance

Aging well: Processing speed inhibition and working memory related to balance and aerobic endurance.

Science.gov (United States)

Zettel-Watson, Laura; Suen, Meagan; Wehbe, Lara; Rutledge, Dana N; Cherry, Barbara J

2017-01-01

The present study explored whether certain physical performance measures could be linked to specific cognitive domains in healthy older adults. A total of 50 adults (mean age 69.5 years, SD 8.1) were evaluated on physical performance using measures of balance (Fullerton Advanced Balance Scale), functional mobility (8-ft up-and-go), lower body strength (30-s chair stand), gait (30-ft walk velocity) and aerobic endurance (6-min walk). Cognitive measures included Stroop Color-Word Test, Digit Span Backward, Trail Making Tests, Everyday Problems Test, Digit Symbol Substitution and a Brown-Peterson test. Principal component analyses reduced cognition to domains of processing speed, inhibition and working memory. Hierarchical regression analyses were carried out with age and each physical measure as potential predictors of the three cognitive domains. The balance scale and 6-min walk were specifically associated with processing speed, inhibition and working memory. Better dynamic balance and aerobic endurance predicted enhanced processing speed, inhibition and working memory in older adults, with these last two domains considered components of executive function. Geriatr Gerontol Int 2017; 17: 108-115. © 2015 Japan Geriatrics Society.

Reading component skills in dyslexia: word recognition, comprehension and processing speed

Directory of Open Access Journals (Sweden)

Darlene Godoy Oliveira

2014-11-01

Full Text Available The cognitive model of reading comprehension posits that reading comprehension is a result of the interaction between decoding and linguistic comprehension. Recently, the notion of decoding skill was expanded to include word recognition. In addition, some studies suggest that other skills could be integrated into this model, like processing speed, and have consistently indicated that this skill influences and is an important predictor of the main components of the model, such as vocabulary for comprehension and phonological awareness of word recognition. The following study evaluated the components of the reading comprehension model and predictive skills in children and adolescents with dyslexia. 40 children and adolescents (8-13 years were divided in a Dyslexic Group (DG, 18 children, MA = 10.78, SD = 1.66 and Control Group (CG 22 children, MA = 10.59, SD = 1.86. All were students from the 2nd to 8th grade of elementary school and groups were equivalent in school grade, age, gender, and IQ. Oral and reading comprehension, word recognition, processing speed, picture naming, receptive vocabulary and phonological awareness were assessed. There were no group differences regarding the accuracy in oral and reading comprehension, phonological awareness, naming, and vocabulary scores. DG performed worse than the CG in word recognition (general score and orthographic confusion items and were slower in naming. Results corroborated the literature regarding word recognition and processing speed deficits in dyslexia. However, dyslexics can achieve normal scores on reading comprehension test. Data supports the importance of delimitation of different reading strategies embedded in the word recognition component. The role of processing speed in reading problems remain unclear.

Acute, low-dose methamphetamine administration improves attention/information processing speed and working memory in methamphetamine-dependent individuals displaying poorer cognitive performance at baseline.

Science.gov (United States)

Mahoney, James J; Jackson, Brian J; Kalechstein, Ari D; De La Garza, Richard; Newton, Thomas F

2011-03-30

Abstinent methamphetamine (Meth) dependent individuals demonstrate poorer performance on tests sensitive to attention/information processing speed, learning and memory, and working memory when compared to non-Meth dependent individuals. The poorer performance on these tests may contribute to the morbidity associated with Meth-dependence. In light of this, we sought to determine the effects of acute, low-dose Meth administration on attention, working memory, and verbal learning and memory in 19 non-treatment seeking, Meth-dependent individuals. Participants were predominantly male (89%), Caucasian (63%), and cigarette smokers (63%). Following a four day, drug-free washout period, participants were given a single-blind intravenous infusion of saline, followed the next day by 30 mg of Meth. A battery of neurocognitive tasks was administered before and after each infusion, and performance on measures of accuracy and reaction time were compared between conditions. While acute Meth exposure did not affect test performance for the entire sample, participants who demonstrated relatively poor performance on these tests at baseline, identified using a median split on each test, showed significant improvement on measures of attention/information processing speed and working memory when administered Meth. Improved performance was seen on the following measures of working memory: choice reaction time task (p≤0.04), a 1-back task (p≤0.01), and a 2-back task (p≤0.04). In addition, those participants demonstrating high neurocognitive performance at baseline experienced similar or decreased performance following Meth exposure. These findings suggest that acute administration of Meth may temporarily improve Meth-associated neurocognitive performance in those individuals experiencing lower cognitive performance at baseline. As a result, stimulants may serve as a successful treatment for improving cognitive functioning in those Meth-dependent individuals experiencing

High speed real-time wavefront processing system for a solid-state laser system

Science.gov (United States)

Liu, Yuan; Yang, Ping; Chen, Shanqiu; Ma, Lifang; Xu, Bing

2008-03-01

A high speed real-time wavefront processing system for a solid-state laser beam cleanup system has been built. This system consists of a core2 Industrial PC (IPC) using Linux and real-time Linux (RT-Linux) operation system (OS), a PCI image grabber, a D/A card. More often than not, the phase aberrations of the output beam from solid-state lasers vary fast with intracavity thermal effects and environmental influence. To compensate the phase aberrations of solid-state lasers successfully, a high speed real-time wavefront processing system is presented. Compared to former systems, this system can improve the speed efficiently. In the new system, the acquisition of image data, the output of control voltage data and the implementation of reconstructor control algorithm are treated as real-time tasks in kernel-space, the display of wavefront information and man-machine conversation are treated as non real-time tasks in user-space. The parallel processing of real-time tasks in Symmetric Multi Processors (SMP) mode is the main strategy of improving the speed. In this paper, the performance and efficiency of this wavefront processing system are analyzed. The opened-loop experimental results show that the sampling frequency of this system is up to 3300Hz, and this system can well deal with phase aberrations from solid-state lasers.

PERFORMANCE OF DIFFERENT CMOS LOGIC STYLES FOR LOW POWER AND HIGH SPEED

OpenAIRE

Sreenivasa Rao.Ijjada; Ayyanna.G; G.Sekhar Reddy; Dr.V.Malleswara Rao

2011-01-01

Designing high-speed low-power circuits with CMOS technology has been a major research problem for many years. Several logic families have been proposed and used to improve circuit performance beyond that of conventional static CMOS family. Fast circuit families are becoming attractive in deep sub micron technologies since the performance benefits obtained from process scaling are decreasing as feature size decreases. This paper presents CMOS differential circuit families such as Dual rail do...

Cognitive Risk Factors for Specific Learning Disorder: Processing Speed, Temporal Processing, and Working Memory.

Science.gov (United States)

Moll, Kristina; Göbel, Silke M; Gooch, Debbie; Landerl, Karin; Snowling, Margaret J

2016-01-01

High comorbidity rates between reading disorder (RD) and mathematics disorder (MD) indicate that, although the cognitive core deficits underlying these disorders are distinct, additional domain-general risk factors might be shared between the disorders. Three domain-general cognitive abilities were investigated in children with RD and MD: processing speed, temporal processing, and working memory. Since attention problems frequently co-occur with learning disorders, the study examined whether these three factors, which are known to be associated with attention problems, account for the comorbidity between these disorders. The sample comprised 99 primary school children in four groups: children with RD, children with MD, children with both disorders (RD+MD), and typically developing children (TD controls). Measures of processing speed, temporal processing, and memory were analyzed in a series of ANCOVAs including attention ratings as covariate. All three risk factors were associated with poor attention. After controlling for attention, associations with RD and MD differed: Although deficits in verbal memory were associated with both RD and MD, reduced processing speed was related to RD, but not MD; and the association with RD was restricted to processing speed for familiar nameable symbols. In contrast, impairments in temporal processing and visuospatial memory were associated with MD, but not RD. © Hammill Institute on Disabilities 2014.

High-Speed On-Board Data Processing for Science Instruments

Science.gov (United States)

Beyon, Jeffrey Y.; Ng, Tak-Kwong; Lin, Bing; Hu, Yongxiang; Harrison, Wallace

2014-01-01

A new development of on-board data processing platform has been in progress at NASA Langley Research Center since April, 2012, and the overall review of such work is presented in this paper. The project is called High-Speed On-Board Data Processing for Science Instruments (HOPS) and focuses on a high-speed scalable data processing platform for three particular National Research Council's Decadal Survey missions such as Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS), Aerosol-Cloud-Ecosystems (ACE), and Doppler Aerosol Wind Lidar (DAWN) 3-D Winds. HOPS utilizes advanced general purpose computing with Field Programmable Gate Array (FPGA) based algorithm implementation techniques. The significance of HOPS is to enable high speed on-board data processing for current and future science missions with its reconfigurable and scalable data processing platform. A single HOPS processing board is expected to provide approximately 66 times faster data processing speed for ASCENDS, more than 70% reduction in both power and weight, and about two orders of cost reduction compared to the state-of-the-art (SOA) on-board data processing system. Such benchmark predictions are based on the data when HOPS was originally proposed in August, 2011. The details of these improvement measures are also presented. The two facets of HOPS development are identifying the most computationally intensive algorithm segments of each mission and implementing them in a FPGA-based data processing board. A general introduction of such facets is also the purpose of this paper.

Performance Characteristics of Long-Track Speed Skaters : A Literature Review

NARCIS (Netherlands)

Konings, Marco J.; Elferink-Gemser, Marije T.; Stoter, Inge K.; van der Meer, Dirk; Otten, Egbert; Hettinga, Florentina J.

Speed skating is an intriguing sport to study from different perspectives due to the peculiar way of motion and the multiple determinants for performance. This review aimed to identify what is known on (long-track) speed skating, and which individual characteristics determine speed skating

Relationships among Linguistic Processing Speed, Phonological Working Memory, and Attention in Children Who Stutter

Science.gov (United States)

Anderson, Julie D.; Wagovich, Stacy A.

2010-01-01

Relatively recently, experimental studies of linguistic processing speed in children who stutter (CWS) have emerged, some of which suggest differences in performance among CWS compared to children who do not stutter (CWNS). What is not yet well understood is the extent to which underlying cognitive skills may impact performance on timed tasks of…

Between-person and within-person associations among processing speed, attention switching, and working memory in younger and older adults.

Science.gov (United States)

Stawski, Robert S; Sliwinski, Martin J; Hofer, Scott M

2013-01-01

BACKGROUND/STUDY CONTEXT: Theories of cognitive aging predict associations among processes that transpire within individuals, but are often tested by examining between-person relationships. The authors provide an empirical demonstration of how associations among measures of processing speed, attention switching, and working memory are different when considered between persons versus within persons over time. A sample of 108 older adults (M (age) = 80.8, range = 66-95) and 68 younger adults (M (age) = 20.2, range = 18-24) completed measures of processing speed, attention switching, and working memory on six occasions over a 14-day period. Multilevel modeling was used to examine processing speed and attention switching performance as predictors of working memory performance simultaneously across days (within-person) and across individuals (between-person). The findings indicates that simple comparison and response speed predicted working memory better than attention switching between persons, whereas attention switching predicted working memory better than simple comparison and response speed within persons over time. Furthermore, the authors did not observe strong evidence of age differences in these associations either within or between persons. The findings of the current study suggest that processing speed is important for understanding between-person and age-related differences in working memory, whereas attention switching is more important for understanding within-person variation in working memory. The authors conclude that theories of cognitive aging should be evaluated by analysis of within-person processes, not exclusively age-related individual differences.

High-Speed 3D Printing of High-Performance Thermosetting Polymers via Two-Stage Curing.

Science.gov (United States)

Kuang, Xiao; Zhao, Zeang; Chen, Kaijuan; Fang, Daining; Kang, Guozheng; Qi, Hang Jerry

2018-04-01

Design and direct fabrication of high-performance thermosets and composites via 3D printing are highly desirable in engineering applications. Most 3D printed thermosetting polymers to date suffer from poor mechanical properties and low printing speed. Here, a novel ink for high-speed 3D printing of high-performance epoxy thermosets via a two-stage curing approach is presented. The ink containing photocurable resin and thermally curable epoxy resin is used for the digital light processing (DLP) 3D printing. After printing, the part is thermally cured at elevated temperature to yield an interpenetrating polymer network epoxy composite, whose mechanical properties are comparable to engineering epoxy. The printing speed is accelerated by the continuous liquid interface production assisted DLP 3D printing method, achieving a printing speed as high as 216 mm h -1 . It is also demonstrated that 3D printing structural electronics can be achieved by combining the 3D printed epoxy composites with infilled silver ink in the hollow channels. The new 3D printing method via two-stage curing combines the attributes of outstanding printing speed, high resolution, low volume shrinkage, and excellent mechanical properties, and provides a new avenue to fabricate 3D thermosetting composites with excellent mechanical properties and high efficiency toward high-performance and functional applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Information processing. [in human performance

Science.gov (United States)

Wickens, Christopher D.; Flach, John M.

1988-01-01

Theoretical models of sensory-information processing by the human brain are reviewed from a human-factors perspective, with a focus on their implications for aircraft and avionics design. The topics addressed include perception (signal detection and selection), linguistic factors in perception (context provision, logical reversals, absence of cues, and order reversals), mental models, and working and long-term memory. Particular attention is given to decision-making problems such as situation assessment, decision formulation, decision quality, selection of action, the speed-accuracy tradeoff, stimulus-response compatibility, stimulus sequencing, dual-task performance, task difficulty and structure, and factors affecting multiple task performance (processing modalities, codes, and stages).

A New Turbo-shaft Engine Control Law during Variable Rotor Speed Transient Process

Science.gov (United States)

Hua, Wei; Miao, Lizhen; Zhang, Haibo; Huang, Jinquan

2015-12-01

A closed-loop control law employing compressor guided vanes is firstly investigated to solve unacceptable fuel flow dynamic change in single fuel control for turbo-shaft engine here, especially for rotorcraft in variable rotor speed process. Based on an Augmented Linear Quadratic Regulator (ALQR) algorithm, a dual-input, single-output robust control scheme is proposed for a turbo-shaft engine, involving not only the closed loop adjustment of fuel flow but also that of compressor guided vanes. Furthermore, compared to single fuel control, some digital simulation cases using this new scheme about variable rotor speed have been implemented on the basis of an integrated system of helicopter and engine model. The results depict that the command tracking performance to the free turbine rotor speed can be asymptotically realized. Moreover, the fuel flow transient process has been significantly improved, and the fuel consumption has been dramatically cut down by more than 2% while keeping the helicopter level fight unchanged.

Attention, processing speed, and executive functioning in pediatric brain tumor survivors treated with proton beam radiation therapy.

Science.gov (United States)

Antonini, Tanya N; Ris, M Douglas; Grosshans, David R; Mahajan, Anita; Okcu, M Fatih; Chintagumpala, Murali; Paulino, Arnold; Child, Amanda E; Orobio, Jessica; Stancel, Heather H; Kahalley, Lisa S

2017-07-01

This study examines attention, processing speed, and executive functioning in pediatric brain tumor survivors treated with proton beam radiation therapy (PBRT). We examined 39 survivors (age 6-19years) who were 3.61years post-PBRT on average. Craniospinal (CSI; n=21) and focal (n=18) subgroups were analyzed. Attention, processing speed, and executive functioning scores were compared to population norms, and clinical/demographic risk factors were examined. As a group, survivors treated with focal PBRT exhibited attention, processing speed, and executive functioning that did not differ from population norms (all p>0.05). Performance in the CSI group across attention scales was normative (all p>0.05), but areas of relative weakness were identified on one executive functioning subtest and several processing speed subtests (all pexecutive functioning remained intact and within normal limits for survivors treated with focal PBRT. Among survivors treated with CSI, a score pattern emerged that was suggestive of difficulties in underlying component skills (i.e., processing speed) rather than true executive dysfunction. No evidence of profound cognitive impairment was found in either group. Copyright © 2017 Elsevier B.V. All rights reserved.

Parameter design and performance analysis of shift actuator for a two-speed automatic mechanical transmission for pure electric vehicles

Directory of Open Access Journals (Sweden)

Jianjun Hu

2016-08-01

Full Text Available Recent developments of pure electric vehicles have shown that pure electric vehicles equipped with two-speed or multi-speed gearbox possess higher energy efficiency by ensuring the drive motor operates at its peak performance range. This article presents the design, analysis, and control of a two-speed automatic mechanical transmission for pure electric vehicles. The shift actuator is based on a motor-controlled camshaft where a special geometric groove is machined, and the camshaft realizes the axial positions of the synchronizer sleeve for gear engaging, disengaging, and speed control of the drive motor. Based on the force analysis of shift process, the parameters of shift actuator and shift motor are designed. The drive motor’s torque control strategy before shifting, speed governing control strategy before engaging, shift actuator’s control strategy during gear engaging, and drive motor’s torque recovery strategy after shift process are proposed and implemented with a prototype. To validate the performance of the two-speed gearbox, a test bed was developed based on dSPACE that emulates various operation conditions. The experimental results indicate that the shift process with the proposed shift actuator and control strategy could be accomplished within 1 s under various operation conditions, with shift smoothness up to passenger car standard.

Design for manufacturing and assembly key performance indicators to support high-speed product development

DEFF Research Database (Denmark)

Thompson, Mary Kathryn; Juel Jespersen, Ida Kirstine; Kjærgaard, Thomas

2018-01-01

Design for Manufacturing and Assembly (DfMA) has great potential for minimizing late engineering changes (ECs) that impede high-speed product development and delay time-to-profit. However, our understanding of DfMA and its implementation in industry is still incomplete. This paper presents...... an industrial case study on late ECs in high-speed product development and compares the results to other examples from the literature. It then proposes a framework with sets of key performance indicators (KPIs) to measure and improve producability and product quality throughout the product development process....

Neural correlates of the difference between working memory speed and simple sensorimotor speed: an fMRI study.

Directory of Open Access Journals (Sweden)

Hikaru Takeuchi

Full Text Available The difference between the speed of simple cognitive processes and the speed of complex cognitive processes has various psychological correlates. However, the neural correlates of this difference have not yet been investigated. In this study, we focused on working memory (WM for typical complex cognitive processes. Functional magnetic resonance imaging data were acquired during the performance of an N-back task, which is a measure of WM for typical complex cognitive processes. In our N-back task, task speed and memory load were varied to identify the neural correlates responsible for the difference between the speed of simple cognitive processes (estimated from the 0-back task and the speed of WM. Our findings showed that this difference was characterized by the increased activation in the right dorsolateral prefrontal cortex (DLPFC and the increased functional interaction between the right DLPFC and right superior parietal lobe. Furthermore, the local gray matter volume of the right DLPFC was correlated with participants' accuracy during fast WM tasks, which in turn correlated with a psychometric measure of participants' intelligence. Our findings indicate that the right DLPFC and its related network are responsible for the execution of the fast cognitive processes involved in WM. Identified neural bases may underlie the psychometric differences between the speed with which subjects perform simple cognitive tasks and the speed with which subjects perform more complex cognitive tasks, and explain the previous traditional psychological findings.

Effect of Speed of Processing Training on Older Driver Screening Measures

Directory of Open Access Journals (Sweden)

Ranmalee Eramudugolla

2017-10-01

Full Text Available Objective: Computerized training for cognitive enhancement is of great public interest, however, there is inconsistent evidence for the transfer of training gains to every day activity. Several large trials have focused on speed of processing (SOP training with some promising findings for long-term effects on daily activity, but no immediate transfer to other cognitive tests. Here, we examine the transfer of SOP training gains to cognitive measures that are known predictors of driving safety in older adults.Methods: Fifty-three adults aged 65–87 years who were current drivers participated in a two group non-randomized design with repeated measures and a no-contact matched control group. The Intervention group completed an average of 7.9 (SD = 3.0 hours of self-administered online SOP training at home. Control group was matched on age, gender and test-re-test interval. Measures included the Useful Field of View (UFOV test, a Hazard Perception test, choice reaction time (Cars RT, Trail Making Test B, a Maze test, visual motion threshold, as well as road craft and road knowledge tests.Results: Speed of processing training resulted in significant improvement in processing speed on the UFOV test relative to controls, with an average change of -45.8 ms (SE = 14.5, and effect size of ω2 = 0.21. Performance on the Maze test also improved, but significant slowing on the Hazard Perception test was observed after SOP training. Training effects on the UFOV task was associated with similar effects on the Cars RT, but not the Hazard Perception and Maze tests, suggesting transfer to some but not all driving related measures. There were no effects of training on any of the other measures examined.Conclusion: Speed of processing training effects on the UFOV task can be achieved with self-administered, online training at home, with some transfer to other cognitive tests. However, differential effects of training may be observed for tasks requiring goal

Effect of Speed of Processing Training on Older Driver Screening Measures.

Science.gov (United States)

Eramudugolla, Ranmalee; Kiely, Kim M; Chopra, Sidhant; Anstey, Kaarin J

2017-01-01

Objective: Computerized training for cognitive enhancement is of great public interest, however, there is inconsistent evidence for the transfer of training gains to every day activity. Several large trials have focused on speed of processing (SOP) training with some promising findings for long-term effects on daily activity, but no immediate transfer to other cognitive tests. Here, we examine the transfer of SOP training gains to cognitive measures that are known predictors of driving safety in older adults. Methods: Fifty-three adults aged 65-87 years who were current drivers participated in a two group non-randomized design with repeated measures and a no-contact matched control group. The Intervention group completed an average of 7.9 ( SD = 3.0) hours of self-administered online SOP training at home. Control group was matched on age, gender and test-re-test interval. Measures included the Useful Field of View (UFOV) test, a Hazard Perception test, choice reaction time (Cars RT), Trail Making Test B, a Maze test, visual motion threshold, as well as road craft and road knowledge tests. Results: Speed of processing training resulted in significant improvement in processing speed on the UFOV test relative to controls, with an average change of -45.8 ms ( SE = 14.5), and effect size of ω 2 = 0.21. Performance on the Maze test also improved, but significant slowing on the Hazard Perception test was observed after SOP training. Training effects on the UFOV task was associated with similar effects on the Cars RT, but not the Hazard Perception and Maze tests, suggesting transfer to some but not all driving related measures. There were no effects of training on any of the other measures examined. Conclusion: Speed of processing training effects on the UFOV task can be achieved with self-administered, online training at home, with some transfer to other cognitive tests. However, differential effects of training may be observed for tasks requiring goal-directed search

Reaction time, processing speed and sustained attention in schizophrenia: impact on social functioning.

Science.gov (United States)

Lahera, Guillermo; Ruiz, Alicia; Brañas, Antía; Vicens, María; Orozco, Arantxa

Previous studies have linked processing speed with social cognition and functioning of patients with schizophrenia. A discriminant analysis is needed to determine the different components of this neuropsychological construct. This paper analyzes the impact of processing speed, reaction time and sustained attention on social functioning. 98 outpatients between 18 and 65 with DSM-5 diagnosis of schizophrenia, with a period of 3 months of clinical stability, were recruited. Sociodemographic and clinical data were collected, and the following variables were measured: processing speed (Trail Making Test [TMT], symbol coding [BACS], verbal fluency), simple and elective reaction time, sustained attention, recognition of facial emotions and global functioning. Processing speed (measured only through the BACS), sustained attention (CPT) and elective reaction time (but not simple) were associated with functioning. Recognizing facial emotions (FEIT) correlated significantly with scores on measures of processing speed (BACS, Animals, TMT), sustained attention (CPT) and reaction time. The linear regression model showed a significant relationship between functioning, emotion recognition (P=.015) and processing speed (P=.029). A deficit in processing speed and facial emotion recognition are associated with worse global functioning in patients with schizophrenia. Copyright © 2017 SEP y SEPB. Publicado por Elsevier España, S.L.U. All rights reserved.

Longitudinal Mediation of Processing Speed on Age-Related Change in Memory and Fluid Intelligence

Science.gov (United States)

Robitaille, Annie; Piccinin, Andrea M.; Muniz, Graciela; Hoffman, Lesa; Johansson, Boo; Deeg, Dorly J.H.; Aartsen, Marja J.; Comijs, Hannie C.; Hofer, Scott M.

2014-01-01

Age-related decline in processing speed has long been considered a key driver of cognitive aging. While the majority of empirical evidence for the processing speed hypothesis has been obtained from analyses of between-person age differences, longitudinal studies provide a direct test of within-person change. Using recent developments in longitudinal mediation analysis, we examine the speed–mediation hypothesis at both the within- and between-person levels in two longitudinal studies, LASA and OCTO-Twin. We found significant within-person indirect effects of change in age, such that increasing age was related to lower speed which, in turn, relates to lower performance across repeated measures on other cognitive outcomes. Although between-person indirect effects were also significant in LASA, they were not in OCTO-Twin. These differing magnitudes of direct and indirect effects across levels demonstrate the importance of separating between- and within-person effects in evaluating theoretical models of age-related change. PMID:23957224

Inhibitory processes, working memory, phonological awareness, naming speed, and early arithmetic achievement.

Science.gov (United States)

Navarro, Jose I; Aguilar, Manuel; Alcalde, Concepcion; Ruiz, Gonzalo; Marchena, Esperanza; Menacho, Inmaculada

2011-11-01

This study identified the cognitive processes that underlie the individual differences in early mathematical performance in elementary school children. Taking into account the Baddeley framework multicomponent model, the inhibitory processes, working memory, phonological awareness, and naming speed are considered to be related to early math learning. To examine this relationship, we compared the performance of a total of 424 typically developing middle-class children, aged between 4 and 7 years in a battery of cognitive and early numeric tests: The Utrecht Early Numeracy Test, the Rapid Automatized Naming Test, Spanish version of the Stroop task, the Numeracy Interference Test, Digit Span test, and Phonological Knowledge Test. The mean age of the participants was 72.21 months (sd = 14.8), and 48.6% were male and 51.4% were female. The results demonstrated that children performing worst on central executive, phonological processing, and inhibitory processes showed lower results in early mathematical tasks measured by The Utrecht Early Numeracy Test. Results supported the notion that the executive system is an important predictor of children's mathematical performance.

Individual differences and predictors of forgetting in old age: the role of processing speed and working memory.

Science.gov (United States)

Zimprich, Daniel; Kurtz, Tanja

2013-01-01

The goal of the present study was to examine whether individual differences in basic cognitive abilities, processing speed, and working memory, are reliable predictors of individual differences in forgetting rates in old age. The sample for the present study comprised 364 participants aged between 65 and 80 years from the Zurich Longitudinal Study on Cognitive Aging. The impact of basic cognitive abilities on forgetting was analyzed by modeling working memory and processing speed as predictors of the amount of forgetting of 27 words, which had been learned across five trials. Forgetting was measured over a 30-minute interval by using parceling and a latent change model, in which the latent difference between recall performance after five learning trials and a delayed recall was modeled. Results implied reliable individual differences in forgetting. These individual differences in forgetting were strongly related to processing speed and working memory. Moreover, an age-related effect, which was significantly stronger for forgetting than for learning, emerged even after controlling effects of processing speed and working memory.

Super-resolution processing for pulsed neutron imaging system using a high-speed camera

International Nuclear Information System (INIS)

Ishizuka, Ken; Kai, Tetsuya; Shinohara, Takenao; Segawa, Mariko; Mochiki, Koichi

2015-01-01

Super-resolution and center-of-gravity processing improve the resolution of neutron-transmitted images. These processing methods calculate the center-of-gravity pixel or sub-pixel of the neutron point converted into light by a scintillator. The conventional neutron-transmitted image is acquired using a high-speed camera by integrating many frames when a transmitted image with one frame is not provided. It succeeds in acquiring the transmitted image and calculating a spectrum by integrating frames of the same energy. However, because a high frame rate is required for neutron resonance absorption imaging, the number of pixels of the transmitted image decreases, and the resolution decreases to the limit of the camera performance. Therefore, we attempt to improve the resolution by integrating the frames after applying super-resolution or center-of-gravity processing. The processed results indicate that center-of-gravity processing can be effective in pulsed-neutron imaging with a high-speed camera. In addition, the results show that super-resolution processing is effective indirectly. A project to develop a real-time image data processing system has begun, and this system will be used at J-PARC in JAEA. (author)

Gravitational Field effects on the Decoherence Process and the Quantum Speed Limit.

Science.gov (United States)

Dehdashti, Sh; Avazzadeh, Z; Xu, Z; Shen, J Q; Mirza, B; Wang, H

2017-11-08

In this paper we use spinor transformations under local Lorentz transformations to investigate the curvature effect on the quantum-to-classical transition, described in terms of the decoherence process and of the quantum speed limit. We find that gravitational fields (introduced adopting the Schwarzschild and anti-de Sitter geometries) affect both the decoherence process and the quantum speed limit of a quantum particle with spin-1/2. In addition, as a tangible example, we study the effect of the Earth's gravitational field, characterized by the Rindler space-time, on the same particle. We find that the effect of the Earth's gravitational field on the decoherence process and quantum speed limit is very small, except when the mean speed of the quantum particle is comparable to the speed of light.

Accounting for the speed shear in wind turbine power performance measurement

Energy Technology Data Exchange (ETDEWEB)

Wagner, R.

2010-04-15

The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise the wind field in front of the turbine. However, with the growing size of the turbine rotors during the last years, the effect of the variations of the wind speed within the swept rotor area, and therefore of the power output, cannot be ignored any longer. Primary effects on the power performance are from the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear condition, therefore on the season and the site. It was then proposed to use an equivalent wind speed accounting for the whole speed profile in front of the turbine. The method was first tested with aerodynamic simulations of a multi-megawatt wind turbine which demonstrated the decrease of the scatter in the power curve. A power curve defined in terms of this equivalent wind speed would be less dependant on the shear than the standard power curve. The equivalent wind speed method was then experimentally validated with lidar measurements. Two equivalent wind speed definitions were considered both resulting in the reduction of the scatter in the power curve. As a lidar wind profiler can measure the wind speed at several heights within the rotor span, the wind speed profile is described with more accuracy than with the power law model. The equivalent wind speed derived from measurements, including at least one measurement above hub height, resulted in a smaller scatter in the power curve than the equivalent wind speed derived from profiles extrapolated from measurements

Processing speed and working memory span: their differential role in superficial and deep memory processes in schizophrenia.

Science.gov (United States)

Brébion, Gildas; Bressan, Rodrigo A; Pilowsky, Lyn S; David, Anthony S

2011-05-01

Previous work has suggested that decrement in both processing speed and working memory span plays a role in the memory impairment observed in patients with schizophrenia. We undertook a study to examine simultaneously the effect of these two factors. A sample of 49 patients with schizophrenia and 43 healthy controls underwent a battery of verbal and visual memory tasks. Superficial and deep encoding memory measures were tallied. We conducted regression analyses on the various memory measures, using processing speed and working memory span as independent variables. In the patient group, processing speed was a significant predictor of superficial and deep memory measures in verbal and visual memory. Working memory span was an additional significant predictor of the deep memory measures only. Regression analyses involving all participants revealed that the effect of diagnosis on all the deep encoding memory measures was reduced to non-significance when processing speed was entered in the regression. Decreased processing speed is involved in verbal and visual memory deficit in patients, whether the task require superficial or deep encoding. Working memory is involved only insofar as the task requires a certain amount of effort.

Comparison of Taxi Time Prediction Performance Using Different Taxi Speed Decision Trees

Science.gov (United States)

Lee, Hanbong

2017-01-01

In the STBO modeler and tactical surface scheduler for ATD-2 project, taxi speed decision trees are used to calculate the unimpeded taxi times of flights taxiing on the airport surface. The initial taxi speed values in these decision trees did not show good prediction accuracy of taxi times. Using the more recent, reliable surveillance data, new taxi speed values in ramp area and movement area were computed. Before integrating these values into the STBO system, we performed test runs using live data from Charlotte airport, with different taxi speed settings: 1) initial taxi speed values and 2) new ones. Taxi time prediction performance was evaluated by comparing various metrics. The results show that the new taxi speed decision trees can calculate the unimpeded taxi-out times more accurately.

Multicast Performance Analysis for High-Speed Torus Networks

National Research Council Canada - National Science Library

Oral, S; George, A

2002-01-01

... for unicast-based and path-based multicast communication on high-speed torus networks. Software-based multicast performance results of selected algorithms on a 16-node Scalable Coherent Interface (SCI) torus are given...

Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS

Directory of Open Access Journals (Sweden)

Jennifer A. Foley

2017-01-01

Full Text Available Objective. Reduced verbal fluency is a strikingly uniform finding following deep brain stimulation (DBS for Parkinson’s disease (PD. The precise cognitive mechanism underlying this reduction remains unclear, but theories have suggested reduced motivation, linguistic skill, and/or executive function. It is of note, however, that previous reports have failed to consider the potential role of any changes in speed of processing. Thus, the aim of this study was to examine verbal fluency changes with a particular focus on the role of cognitive speed. Method. In this study, 28 patients with PD completed measures of verbal fluency, motivation, language, executive functioning, and speed of processing, before and after DBS. Results. As expected, there was a marked decline in verbal fluency but also in a timed test of executive functions and two measures of speed of processing. Verbal fluency decline was associated with markers of linguistic and executive functioning, but not after speed of processing was statistically controlled for. In contrast, greater decline in verbal fluency was associated with higher levels of apathy at baseline, which was not associated with changes in cognitive speed. Discussion. Reduced generativity and processing speed may account for the marked reduction in verbal fluency commonly observed following DBS.

Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS

Science.gov (United States)

Foltynie, Tom; Zrinzo, Ludvic; Hyam, Jonathan A.; Limousin, Patricia

2017-01-01

Objective. Reduced verbal fluency is a strikingly uniform finding following deep brain stimulation (DBS) for Parkinson's disease (PD). The precise cognitive mechanism underlying this reduction remains unclear, but theories have suggested reduced motivation, linguistic skill, and/or executive function. It is of note, however, that previous reports have failed to consider the potential role of any changes in speed of processing. Thus, the aim of this study was to examine verbal fluency changes with a particular focus on the role of cognitive speed. Method. In this study, 28 patients with PD completed measures of verbal fluency, motivation, language, executive functioning, and speed of processing, before and after DBS. Results. As expected, there was a marked decline in verbal fluency but also in a timed test of executive functions and two measures of speed of processing. Verbal fluency decline was associated with markers of linguistic and executive functioning, but not after speed of processing was statistically controlled for. In contrast, greater decline in verbal fluency was associated with higher levels of apathy at baseline, which was not associated with changes in cognitive speed. Discussion. Reduced generativity and processing speed may account for the marked reduction in verbal fluency commonly observed following DBS. PMID:28408788

Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS.

Science.gov (United States)

Foley, Jennifer A; Foltynie, Tom; Zrinzo, Ludvic; Hyam, Jonathan A; Limousin, Patricia; Cipolotti, Lisa

2017-01-01

Objective . Reduced verbal fluency is a strikingly uniform finding following deep brain stimulation (DBS) for Parkinson's disease (PD). The precise cognitive mechanism underlying this reduction remains unclear, but theories have suggested reduced motivation, linguistic skill, and/or executive function. It is of note, however, that previous reports have failed to consider the potential role of any changes in speed of processing. Thus, the aim of this study was to examine verbal fluency changes with a particular focus on the role of cognitive speed. Method . In this study, 28 patients with PD completed measures of verbal fluency, motivation, language, executive functioning, and speed of processing, before and after DBS. Results . As expected, there was a marked decline in verbal fluency but also in a timed test of executive functions and two measures of speed of processing. Verbal fluency decline was associated with markers of linguistic and executive functioning, but not after speed of processing was statistically controlled for. In contrast, greater decline in verbal fluency was associated with higher levels of apathy at baseline, which was not associated with changes in cognitive speed. Discussion . Reduced generativity and processing speed may account for the marked reduction in verbal fluency commonly observed following DBS.

Effect of extrusion stem speed on extrusion process for a hollow aluminum profile

International Nuclear Information System (INIS)

Zhang, Cunsheng; Zhao, Guoqun; Chen, Zhiren; Chen, Hao; Kou, Fujun

2012-01-01

Highlights: ► Extrusion stem speed has significant effects on extrusion process. ► An optimum value of stem speed exists for uniform metal flow distribution. ► A higher stem speed leads to a higher required extrusion force. ► A high stem speed leads to an improved welding quality of aluminum profile. - Abstract: Extrusion stem speed is one of important process parameters during aluminum profile extrusion, which directly influences the profile quality and choice of extrusion equipments. In this paper, the extrusion process of a thin-walled hollow aluminum profile was simulated by means of the HyperXtrude commercial software. Through a serial of numerical simulation, the effects of stem speed on extrusion process, such as metal flow behavior at die exit, temperature distribution, extrusion force, and welding pressure, have been investigated. The numerical results showed that there existed an optimum value of stem speed for flow velocity distribution. With the increasing stem speed, the temperature of the extrudate and required extrusion force increased, and the welding quality of extrudate would be improved. Through comprehensive comparison and analysis, the appropriate stem speed could be determined for practical extrusion production. Thus, the research results could give effective guideline for determining initial billet and die temperature and choosing the proper extrusion press in aluminum profile industry.

Design of light-small high-speed image data processing system

Science.gov (United States)

Yang, Jinbao; Feng, Xue; Li, Fei

2015-10-01

A light-small high speed image data processing system was designed in order to meet the request of image data processing in aerospace. System was constructed of FPGA, DSP and MCU (Micro-controller), implementing a video compress of 3 million pixels@15frames and real-time return of compressed image to the upper system. Programmable characteristic of FPGA, high performance image compress IC and configurable MCU were made best use to improve integration. Besides, hard-soft board design was introduced and PCB layout was optimized. At last, system achieved miniaturization, light-weight and fast heat dispersion. Experiments show that, system's multifunction was designed correctly and worked stably. In conclusion, system can be widely used in the area of light-small imaging.

Processes of Strategic Renewal, Competencies, and the Management of Speed

OpenAIRE

Volker Mahnke; John Harald Aadne

1998-01-01

We discuss strategic renewal from a competence perspective. We argue that the management of speed and timing in this process is viewed distinctively when perceived through a cognitive lens. Managers need more firmly grounded process-understanding. The key idea of this paper is to dynamically conceptualize key activities of strategic renewal, and possible sources of break-down as they relate to the managment of speed and timing. Based on a case from the media industry, we identify managerial t...

Thermomechanical simulations and experimental validation for high speed incremental forming

Science.gov (United States)

Ambrogio, Giuseppina; Gagliardi, Francesco; Filice, Luigino; Romero, Natalia

2016-10-01

Incremental sheet forming (ISF) consists in deforming only a small region of the workspace through a punch driven by a NC machine. The drawback of this process is its slowness. In this study, a high speed variant has been investigated from both numerical and experimental points of view. The aim has been the design of a FEM model able to perform the material behavior during the high speed process by defining a thermomechanical model. An experimental campaign has been performed by a CNC lathe with high speed to test process feasibility. The first results have shown how the material presents the same performance than in conventional speed ISF and, in some cases, better material behavior due to the temperature increment. An accurate numerical simulation has been performed to investigate the material behavior during the high speed process confirming substantially experimental evidence.

Working memory span in mild cognitive impairment. Influence of processing speed and cognitive reserve.

Science.gov (United States)

Facal, David; Juncos-Rabadán, Onésimo; Pereiro, Arturo X; Lojo-Seoane, Cristina

2014-04-01

Mild cognitive impairment (MCI) often includes episodic memory impairment, but can also involve other types of cognitive decline. Although previous studies have shown poorer performance of MCI patients in working memory (WM) span tasks, different MCI subgroups were not studied. In the present exploratory study, 145 participants underwent extensive cognitive evaluation, which included three different WM span tasks, and were classified into the following groups: multiple-domain amnestic MCI (mda-MCI), single-domain amnestic MCI (sda-MCI), and controls. General linear model was conducted by considering the WM span tasks as the within-subject factor; the group (mda-MCI, sda-MCI, and controls) as the inter-subject factor; and processing speed, vocabulary and age as covariates. Multiple linear regression models were also used to test the influence of processing speed, vocabulary, and other cognitive reserve (CR) proxies. Results indicate different levels of impairment of WM, with more severe impairment in mda-MCI patients. The differences were still present when processing resources and CR were controlled. Between-group differences can be understood as a manifestation of the greater severity and widespread memory impairment in mda-MCI patients and may contribute to a better understanding of continuum from normal controls to mda-MCI patients. Processing speed and CR have a limited influence on WM scores, reducing but not removing differences between groups.

Effect of Performance Speed on Trunk Movement Control During the Curl-Up Exercise

Directory of Open Access Journals (Sweden)

Barbado David

2015-06-01

Full Text Available Trunk exercise speed has significant effects on neuro-mechanical demands; however, the influence of a variety of exercise speeds on motor control of the trunk displacement remains unknown. The aim of this study was to assess the effect of performance speed on trunk motion control during the curl-up exercise by analyzing the kinematic variance about the sagittal trajectory. Seventeen subjects volunteered to perform curl-ups at different cadences controlled by a metronome. Standard deviation (SD and range (RG of shoulder girdle medial-lateral displacement (SGML and detrended fluctuation analysis (DFA of SGML were calculated to examine linear variability and long range autocorrelation of medial-lateral upper trunk displacements, respectively. In addition, SD, RG and DFA of centre of pressure medial-lateral displacement (COPML were performed to analyze the behavior of the motor system while controlling trunk displacement. Although SD and RG of COPML increased as speed increased, the curl-up cadence did not have significant effects on SD and RG of SGML. These results suggest that although high speed curl-ups challenged participants’ ability to carry out medial-lateral adjustments, an increase of performance speed did not modify the linear variability about the sagittal trajectory. Regarding DFA, the scaling exponent α of SGML and COPML was higher for the fastest movements, mainly in long term fluctuations. Therefore, to maintain the target trajectory, participants used different strategies depending on performance speed. This is to say, there were less trajectory changes when participants performed the fastest exercises.

Verbal Knowledge, Working Memory, and Processing Speed as Predictors of Verbal Learning in Older Adults

Science.gov (United States)

Rast, Philippe

2011-01-01

The present study aimed at modeling individual differences in a verbal learning task by means of a latent structured growth curve approach based on an exponential function that yielded 3 parameters: initial recall, learning rate, and asymptotic performance. Three cognitive variables--speed of information processing, verbal knowledge, working…

Information processing speed and attention in multiple sclerosis: Reconsidering the Attention Network Test (ANT).

Science.gov (United States)

Roth, Alexandra K; Denney, Douglas R; Lynch, Sharon G

2015-01-01

The Attention Network Test (ANT) assesses attention in terms of discrepancies between response times to items that differ in the burden they place on some facet of attention. However, simple arithmetic difference scores commonly used to capture these discrepancies fail to provide adequate control for information processing speed, leading to distorted findings when patient and control groups differ markedly in the speed with which they process and respond to stimulus information. This study examined attention networks in patients with multiple sclerosis (MS) using simple difference scores, proportional scores, and residualized scores that control for processing speed through statistical regression. Patients with relapsing-remitting (N = 20) or secondary progressive (N = 20) MS and healthy controls (N = 40) of similar age, education, and gender completed the ANT. Substantial differences between patients and controls were found on all measures of processing speed. Patients exhibited difficulties in the executive control network, but only when difference scores were considered. When deficits in information processing speed were adequately controlled using proportional or residualized score, deficits in the alerting network emerged. The effect sizes for these deficits were notably smaller than those for overall information processing speed and were also limited to patients with secondary progressive MS. Deficits in processing speed are more prominent in MS than those involving attention, and when the former are properly accounted for, differences in the latter are confined to the alerting network.

High-Speed Printing Process Characterization using the Lissajous Trajectory Method

Science.gov (United States)

Lee, Sangwon; Kim, Daekeun

2018-04-01

We present a novel stereolithographic three-dimensional (3D) printing process that uses Lissajous trajectories. By using Lissajous trajectories, this 3D printing process allows two laser-scanning mirrors to operate at similar high-speed frequencies simultaneously, and the printing speed can be faster than that of raster scanning used in conventional stereolithography. In this paper, we first propose the basic theoretical background for this printing process based on Lissajous trajectories. We also characterize its printing conditions, such as printing size, laser spot size, and minimum printing resolution, with respect to the operating frequencies of the scanning mirrors and the capability of the laser modulation. Finally, we demonstrate simulation results for printing basic 2D shapes by using a noble printing process algorithm.

Optimization of Friction Stir Welding Tool Advance Speed via Monte-Carlo Simulation of the Friction Stir Welding Process.

Science.gov (United States)

Fraser, Kirk A; St-Georges, Lyne; Kiss, Laszlo I

2014-04-30

Recognition of the friction stir welding process is growing in the aeronautical and aero-space industries. To make the process more available to the structural fabrication industry (buildings and bridges), being able to model the process to determine the highest speed of advance possible that will not cause unwanted welding defects is desirable. A numerical solution to the transient two-dimensional heat diffusion equation for the friction stir welding process is presented. A non-linear heat generation term based on an arbitrary piecewise linear model of friction as a function of temperature is used. The solution is used to solve for the temperature distribution in the Al 6061-T6 work pieces. The finite difference solution of the non-linear problem is used to perform a Monte-Carlo simulation (MCS). A polynomial response surface (maximum welding temperature as a function of advancing and rotational speed) is constructed from the MCS results. The response surface is used to determine the optimum tool speed of advance and rotational speed. The exterior penalty method is used to find the highest speed of advance and the associated rotational speed of the tool for the FSW process considered. We show that good agreement with experimental optimization work is possible with this simplified model. Using our approach an optimal weld pitch of 0.52 mm/rev is obtained for 3.18 mm thick AA6061-T6 plate. Our method provides an estimate of the optimal welding parameters in less than 30 min of calculation time.

Effects of the process temperature and rolling speed on the thermal roll-to-roll imprint lithography of flexible polycarbonate film

International Nuclear Information System (INIS)

Sohn, Ki-Ju; Lee, Woo Il; Park, Jae Hong; Jang, Hyun-Ik; Lee, Dong-Eon

2013-01-01

Thermal roll-to-roll imprint lithography (R2RIL) is a simple and low-cost process for the mass production of micro/nanopatterns. However, in that it relies on highly viscous thermoplastic resists, it is limited in its ability to imprint precise patterns at a high speed. Moreover, the concentrated imprint force applied in R2RIL can damage the resist material which is structurally vulnerable at high process temperatures. Therefore, it is important to understand the temperature- and time-dependent characteristics of the resist material as well as the imprinting mechanism when using thermal R2RIL. In this work, the effects of the process temperature and rolling speed on thermal R2RIL of polycarbonate (PC) films were investigated to improve the process efficiency. Micro-scale line patterns were successfully transferred onto PC films from nickel (Ni) mold stamps. Consequently, line patterns with widths in the range of 5–80 µm were achieved at a traveling speed of 28.6 mm s –1 and process temperature of 150 °C, which is just above the glass transition temperature (T g ). In addition, the patterning performance was investigated for different temperatures, rolling speeds and pattern sizes. The imprinted pattern profiles were measured by an alpha-step surface profiler to investigate the patterning performance. The results show that a much better imprint performance was achieved at 150 °C, compared to the result at temperatures below T g . The physical mechanisms of thermal R2RIL on a PC film were studied by a finite-element analysis and the patterning process was successfully demonstrated by a visco-plastic deformation model. (paper)

Research of high speed data readout and pre-processing system based on xTCA for silicon pixel detector

International Nuclear Information System (INIS)

Zhao Jingzhou; Lin Haichuan; Guo Fang; Liu Zhen'an; Xu Hao; Gong Wenxuan; Liu Zhao

2012-01-01

As the development of the detector, Silicon pixel detectors have been widely used in high energy physics experiments. It needs data processing system with high speed, high bandwidth and high availability to read data from silicon pixel detectors which generate more large data. The same question occurs on Belle II Pixel Detector which is a new style silicon pixel detector used in SuperKEKB accelerator with high luminance. The paper describes the research of High speed data readout and pre-processing system based on xTCA for silicon pixel detector. The system consists of High Performance Computer Node (HPCN) based on xTCA and ATCA frame. The HPCN consists of 4XFPs based on AMC, 1 AMC Carrier ATCA Board (ACAB) and 1 Rear Transmission Module. It characterized by 5 high performance FPGAs, 16 fiber links based on RocketIO, 5 Gbit Ethernet ports and DDR2 with capacity up to 18GB. In a ATCA frame, 14 HPCNs make up a system using the high speed backplane to achieve the function of data pre-processing and trigger. This system will be used on the trigger and data acquisition system of Belle II Pixel detector. (authors)

Working Memory in Children With Neurocognitive Effects From Sickle Cell Disease: Contributions of the Central Executive and Processing Speed

Science.gov (United States)

Smith, Kelsey E.; Schatz, Jeffrey

2017-01-01

Children with sickle cell disease (SCD) are at risk for working memory deficits due to multiple disease processes. We assessed working memory abilities and related functions in 32 school-age children with SCD and 85 matched comparison children using Baddeley’s working memory model as a framework. Children with SCD performed worse than controls for working memory, central executive function, and processing/rehearsal speed. Central executive function was found to mediate the relationship between SCD status and working memory, but processing speed did not. Cognitive remediation strategies that focus on central executive processes may be important for remediating working memory deficits in SCD. PMID:27759435

Phonological working memory and auditory processing speed in children with specific language impairment

Directory of Open Access Journals (Sweden)

Fatemeh Haresabadi

2015-02-01

Full Text Available Background and Aim: Specific language impairment (SLI, one variety of developmental language disorder, has attracted much interest in recent decades. Much research has been conducted to discover why some children have a specific language impairment. So far, research has failed to identify a reason for this linguistic deficiency. Some researchers believe language disorder causes defects in phonological working memory and affects auditory processing speed. Therefore, this study reviews the results of research investigating these two factors in children with specific language impairment.Recent Findings: Studies have shown that children with specific language impairment face constraints in phonological working memory capacity. Memory deficit is one possible cause of linguistic disorder in children with specific language impairment. However, in these children, disorder in information processing speed is observed, especially regarding the auditory aspect.Conclusion: Much more research is required to adequately explain the relationship between phonological working memory and auditory processing speed with language. However, given the role of phonological working memory and auditory processing speed in language acquisition, a focus should be placed on phonological working memory capacity and auditory processing speed in the assessment and treatment of children with a specific language impairment.

Verbal Processing Speed and Executive Functioning in Long-Term Cochlear Implant Users

Science.gov (United States)

AuBuchon, Angela M.; Pisoni, David B.; Kronenberger, William G.

2015-01-01

Purpose: The purpose of this study was to report how "verbal rehearsal speed" (VRS), a form of covert speech used to maintain verbal information in working memory, and another verbal processing speed measure, perceptual encoding speed, are related to 3 domains of executive function (EF) at risk in cochlear implant (CI) users: verbal…

Psychomotor speed is related to perceived performance in rowers

NARCIS (Netherlands)

Nederhof, Esther; Visscher, Chris; Lemmink, Koen

2008-01-01

The goal of the present study was to determine if psychomotor speed is related to perceived performance. It was hypothesized that lower perceived performance was related to longer reaction times. A total of 85 measurements were taken in 26 varsity rowers (mean age 21.3 years, s=1.6) on five

THE CORRELATION BETWEEN THE PHYSICAL TRAINING AND THE SPORT PERFORMANCES IN SPEED SKATING AT CHILDREN

Directory of Open Access Journals (Sweden)

VAIDA Marius

2010-04-01

Full Text Available Sport practice at an early age is a problem of high actuality, this being debated intensely by specialists,the solving of the problem in cause being appreciated as a highly important factor in the general conception ofthe complex process of sport practice, in this process a very important role being held by the physical training.The present paper approaches the complex problem of the connection between the physical training andthe sport performances at children through an experiment realized on 6 speed skaters, 4 boys and 2 girls, withages of 8-9, experiment that had as purpose the demonstration of the importance of the multilateral physical training at skaters of an early age, of course without excluding the importance of the other factors necessary for superior results.Through the obtained results we proved that there is a direct connection between the physical training and the sport performances at children, knowing that the superior results in speed skating, on a long period, depend also by the training quality at an early age

High-speed AFM for Studying Dynamic Biomolecular Processes

Science.gov (United States)

Ando, Toshio

2008-03-01

Biological molecules show their vital activities only in aqueous solutions. It had been one of dreams in biological sciences to directly observe biological macromolecules (protein, DNA) at work under a physiological condition because such observation is straightforward to understanding their dynamic behaviors and functional mechanisms. Optical microscopy has no sufficient spatial resolution and electron microscopy is not applicable to in-liquid samples. Atomic force microscopy (AFM) can visualize molecules in liquids at high resolution but its imaging rate was too low to capture dynamic biological processes. This slow imaging rate is because AFM employs mechanical probes (cantilevers) and mechanical scanners to detect the sample height at each pixel. It is quite difficult to quickly move a mechanical device of macroscopic size with sub-nanometer accuracy without producing unwanted vibrations. It is also difficult to maintain the delicate contact between a probe tip and fragile samples. Two key techniques are required to realize high-speed AFM for biological research; fast feedback control to maintain a weak tip-sample interaction force and a technique to suppress mechanical vibrations of the scanner. Various efforts have been carried out in the past decade to materialize high-speed AFM. The current high-speed AFM can capture images on video at 30-60 frames/s for a scan range of 250nm and 100 scan lines, without significantly disturbing week biomolecular interaction. Our recent studies demonstrated that this new microscope can reveal biomolecular processes such as myosin V walking along actin tracks and association/dissociation dynamics of chaperonin GroEL-GroES that occurs in a negatively cooperative manner. The capacity of nanometer-scale visualization of dynamic processes in liquids will innovate on biological research. In addition, it will open a new way to study dynamic chemical/physical processes of various phenomena that occur at the liquid-solid interfaces.

Performance Improvement of Servo Machine Low Speed Operation Using RBFN Disturbance Observer

DEFF Research Database (Denmark)

Lee, Kyo-Beum; Blaabjerg, Frede

2004-01-01

A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The typical speed estimation scheme in most servo system for low speed operation is sensitive to the variation of machine parameters, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Networks (RBFN) is applied. The effectiveness of the proposed inertia estimation method is verified by experiments. It is concluded that the speed control performance in the low speed region is improved with the proposed...

Does attention speed up processing? Decreases and increases of processing rates in visual prior entry.

Science.gov (United States)

Tünnermann, Jan; Petersen, Anders; Scharlau, Ingrid

2015-03-02

Selective visual attention improves performance in many tasks. Among others, it leads to "prior entry"--earlier perception of an attended compared to an unattended stimulus. Whether this phenomenon is purely based on an increase of the processing rate of the attended stimulus or if a decrease in the processing rate of the unattended stimulus also contributes to the effect is, up to now, unanswered. Here we describe a novel approach to this question based on Bundesen's Theory of Visual Attention, which we use to overcome the limitations of earlier prior-entry assessment with temporal order judgments (TOJs) that only allow relative statements regarding the processing speed of attended and unattended stimuli. Prevalent models of prior entry in TOJs either indirectly predict a pure acceleration or cannot model the difference between acceleration and deceleration. In a paradigm that combines a letter-identification task with TOJs, we show that indeed acceleration of the attended and deceleration of the unattended stimuli conjointly cause prior entry. © 2015 ARVO.

High Speed/ Low Effluent Process for Ethanol

Energy Technology Data Exchange (ETDEWEB)

M. Clark Dale

2006-10-30

n this project, BPI demonstrated a new ethanol fermentation technology, termed the High Speed/ Low Effluent (HS/LE) process on both lab and large pilot scale as it would apply to wet mill and/or dry mill corn ethanol production. The HS/LE process allows very rapid fermentations, with 18 to 22% sugar syrups converted to 9 to 11% ethanol ‘beers’ in 6 to 12 hours using either a ‘consecutive batch’ or ‘continuous cascade’ implementation. This represents a 5 to 8X increase in fermentation speeds over conventional 72 hour batch fermentations which are the norm in the fuel ethanol industry today. The ‘consecutive batch’ technology was demonstrated on a large pilot scale (4,800 L) in a dry mill corn ethanol plant near Cedar Rapids, IA (Xethanol Biofuels). The pilot demonstrated that 12 hour fermentations can be accomplished on an industrial scale in a non-sterile industrial environment. Other objectives met in this project included development of a Low Energy (LE) Distillation process which reduces the energy requirements for distillation from about 14,000 BTU/gal steam ($0.126/gal with natural gas @ $9.00 MCF) to as low as 0.40 KW/gal electrical requirements ($0.022/gal with electricity @ $0.055/KWH). BPI also worked on the development of processes that would allow application of the HS/LE fermentation process to dry mill ethanol plants. A High-Value Corn ethanol plant concept was developed to produce 1) corn germ/oil, 2) corn bran, 3) ethanol, 4) zein protein, and 5) nutritional protein, giving multiple higher value products from the incoming corn stream.

Accounting for the speed shear in wind turbine power performance measurement

DEFF Research Database (Denmark)

Wagner, Rozenn

the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear...... for turbulence intensity suggested by Albers. The second method was found to be more suitable for normalising the power curve for the turbulence intensity. Using the equivalent wind speed accounting for the wind shear in the power performance measurement was shown to result in a more repeatable power curve than......The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise...

Cognitive Processing Speed, Working Memory, and the Intelligibility of Hearing Aid-Processed Speech in Persons with Hearing Impairment

Directory of Open Access Journals (Sweden)

Wycliffe Kabaywe Yumba

2017-08-01

Full Text Available Previous studies have demonstrated that successful listening with advanced signal processing in digital hearing aids is associated with individual cognitive capacity, particularly working memory capacity (WMC. This study aimed to examine the relationship between cognitive abilities (cognitive processing speed and WMC and individual listeners’ responses to digital signal processing settings in adverse listening conditions. A total of 194 native Swedish speakers (83 women and 111 men, aged 33–80 years (mean = 60.75 years, SD = 8.89, with bilateral, symmetrical mild to moderate sensorineural hearing loss who had completed a lexical decision speed test (measuring cognitive processing speed and semantic word-pair span test (SWPST, capturing WMC participated in this study. The Hagerman test (capturing speech recognition in noise was conducted using an experimental hearing aid with three digital signal processing settings: (1 linear amplification without noise reduction (NoP, (2 linear amplification with noise reduction (NR, and (3 non-linear amplification without NR (“fast-acting compression”. The results showed that cognitive processing speed was a better predictor of speech intelligibility in noise, regardless of the types of signal processing algorithms used. That is, there was a stronger association between cognitive processing speed and NR outcomes and fast-acting compression outcomes (in steady state noise. We observed a weaker relationship between working memory and NR, but WMC did not relate to fast-acting compression. WMC was a relatively weaker predictor of speech intelligibility in noise. These findings might have been different if the participants had been provided with training and or allowed to acclimatize to binary masking noise reduction or fast-acting compression.

New limit theorems for regular diffusion processes with finite speed measure

NARCIS (Netherlands)

J.H. van Zanten (Harry)

2000-01-01

textabstractWe derive limit theorems for diffusion processes that have a finite speed measure. First we prove a number of asymptotic properties of the density $rho_t = dmu_t /dmu$ of the empirical measure $mu_t$ with respect to the normalized speed measure $mu$. These results are then used to derive

Processing of Instantaneous Angular Speed Signal for Detection of a Diesel Engine Failure

Directory of Open Access Journals (Sweden)

Adam Charchalis

2013-01-01

Full Text Available Continuous monitoring of diesel engine performance under its operating is critical for the prediction of malfunction development and subsequently functional failure detection. Analysis of instantaneous angular speed (IAS of the crankshaft is considered as one of the nonintrusive and effective methods of the detection of combustion quality deterioration. In this paper results of experimental verification of fuel system's malfunction detecting, using optical encoder for IAS recording are presented. The implemented method relies on the comparison of measurement results, recorded under healthy and faulty conditions of the engine. Elaborated dynamic model of angular speed variations enables us to build templates of engine behavior. Recorded during experiment, values of cylinder pressure were taken for the approximation of pressure basic waveform. The main task of data processing is smoothing the raw angular speed signal. The noise is due to sensor mount vibrations, signal emitter machining, engine body vibrations, and crankshaft torsional vibrations. Smoothing of the measurement data was carried out by the implementation of the Savitzky-Golay filter. Measured signal after smoothing was compared with the model of IAS run.

Sensitometric characteristics of D-, E- and F-speed dental radiographic films in manual and automatic processing

Directory of Open Access Journals (Sweden)

Jahangir Haghani

2012-12-01

Full Text Available BACKGROUND: The purpose of this study was to evaluate the sensitometric characteristics of Ultraspeed, Ektaspeed Plus and Insight dental radiographic films using manual and automatic processing systems. METHODS: In this experimental invitro study, an aluminum step-wedge was used to construct characteristic curves for D-, E- and F-speed radiographic films (Kodak Eastman, Rochester, USA. All films were processed in Iranian processing solution (chemical industries Co., Iran, Tehran both manually and automatically in a period of six days. Unexposed films of three types were processed manually and automatically to determine base plus fog density. Speed and film contrast were measured according to International Standard Organization definition. RESULTS: There was significant difference in density obtained with the D-, E- and F-speed films in both manually and automatically processing systems (P < 0.001. There was significant difference in density obtained with the Ultraspeed and insight films. There was no significant difference in contrast obtained with the D-, E- and F-speed films in both manually and automatically processing systems (P = 0.255 , P = 0.26. There was significant difference in speed obtained with the D-, E- and F-speed films in both manually and automatically processing systems (P = 0.034, P = 0.04. CONCLUSIONS: The choice of processing system can affect radiographic characteristics. The F-speed film processed in automatic system has greater speed in comparison with manual processing system, and it provides a further reduction in radiation exposure without detriment to image quality.

Effect of wind speed on performance of a solar-pv array

Science.gov (United States)

Thousands of solar photovoltaic (PV) arrays have been installed over the past few years, but the effect of wind speed on the predicted performance of PV arrays is not usually considered by installers. An increase in wind speed will cool the PV array, and the electrical power of the PV modules will ...

Analogical reasoning and aging: the processing speed and inhibition hypothesis.

Science.gov (United States)

Bugaiska, Aurélia; Thibaut, Jean-Pierre

2015-01-01

This study was designed to investigate the effect of aging on analogical reasoning by manipulating the strength of semantic association (LowAssoc or HighAssoc) and the number of distracters' semantic analogies of the A:B::C:D type and to determine which factors might be responsible for the age-related differences on analogical reasoning by testing two different theoretical frameworks: the inhibition hypothesis and the speed mediation hypothesis. We compared young adults and two groups of aging people (old and old-old) with word analogies of the A:B::C:D format. Results indicate an age-related effect on analogical reasoning, this effect being greatest with LowAssoc analogies. It was not associated with the presence of semantic distractors. Moreover, the results show that the variance part of the analogy task due to age was mainly explained by processing speed (rather than by inhibition) in the case of old participants and by both processing speed and inhibition in the old-old group. These results are discussed in relation to current models of aging and their interaction with the processes involved in analogical reasoning.

Parallel processing method for high-speed real time digital pulse processing for gamma-ray spectroscopy

International Nuclear Information System (INIS)

Fernandes, A.M.; Pereira, R.C.; Sousa, J.; Neto, A.; Carvalho, P.; Batista, A.J.N.; Carvalho, B.B.; Varandas, C.A.F.; Tardocchi, M.; Gorini, G.

2010-01-01

A new data acquisition (DAQ) system was developed to fulfil the requirements of the gamma-ray spectrometer (GRS) JET-EP2 (joint European Torus enhancement project 2), providing high-resolution spectroscopy at very high-count rate (up to few MHz). The system is based on the Advanced Telecommunications Computing Architecture TM (ATCA TM ) and includes a transient record (TR) module with 8 channels of 14 bits resolution at 400 MSamples/s (MSPS) sampling rate, 4 GB of local memory, and 2 field programmable gate array (FPGA) able to perform real time algorithms for data reduction and digital pulse processing. Although at 400 MSPS only fast programmable devices such as FPGAs can be used either for data processing and data transfer, FPGA resources also present speed limitation at some specific tasks, leading to an unavoidable data lost when demanding algorithms are applied. To overcome this problem and foreseeing an increase of the algorithm complexity, a new digital parallel filter was developed, aiming to perform real time pulse processing in the FPGAs of the TR module at the presented sampling rate. The filter is based on the conventional digital time-invariant trapezoidal shaper operating with parallelized data while performing pulse height analysis (PHA) and pile up rejection (PUR). The incoming sampled data is successively parallelized and fed into the processing algorithm block at one fourth of the sampling rate. The following data processing and data transfer is also performed at one fourth of the sampling rate. The algorithm based on data parallelization technique was implemented and tested at JET facilities, where a spectrum was obtained. Attending to the observed results, the PHA algorithm will be improved by implementing the pulse pile up discrimination.

Performance Analysis of High-Speed Deep/Shallow Recessed Hybrid Bearing

Directory of Open Access Journals (Sweden)

Lei Wang

2013-01-01

Full Text Available The present paper proposes a theoretical analysis of the performance of deep/shallow recessed hybrid bearing. It is intended that, on the basis of the numerical results drawn from this study, appropriate shallow recess depth and width can be determined for use in the bearing design process. By adopting bulk flow theory, the turbulent Reynolds equation and energy equation are modified and solved numerically including concentrated inertia effects at the recess edge with different depth and width of shallow recess. The results indicate that the load capacity, drag torque increases as the depth of shallow recess is shallower and the width ratio (half angle of deep recess versus half angle of shallow recess is smaller. In contrast, the flow rate decreases as the depth of shallow recess is shallower and the width ratio is smaller. Nevertheless, the appropriate design of the depth and width of shallow recess might well induce the performance of high-speed deep/shallow recessed hybrid bearing.

High performance multi-channel high-speed I/O circuits

CERN Document Server

Oh, Taehyoun

2013-01-01

This book describes design techniques that can be used to mitigate crosstalk in high-speed I/O circuits. The focus of the book is in developing compact and low power integrated circuits for crosstalk cancellation, inter-symbol interference (ISI) mitigation and improved bit error rates (BER) at higher speeds. This book is one of the first to discuss in detail the problem of crosstalk and ISI mitigation encountered as data rates have continued beyond 10Gb/s. Readers will learn to avoid the data performance cliff, with circuits and design techniques described for novel, low power crosstalk cancel

Wingate Test is a Strong Predictor of 1500m Performance in Elite Speed Skaters

NARCIS (Netherlands)

Hofman, Nico; Orie, Jac; Hoozemans, Marco J M; Foster Jr., Carl; de Koning, Jos J

2017-01-01

Wingate test scores are strongly associated with anaerobic capacity in athletes involved in speed-endurance sports. In speed skating Wingate results are known to predict performance cross-sectionally, but have not been investigated relative to their ability to predict performance longitudinally.

In-process, non-destructive, dynamic testing of high-speed polymer composite rotors

Science.gov (United States)

Kuschmierz, Robert; Filippatos, Angelos; Günther, Philipp; Langkamp, Albert; Hufenbach, Werner; Czarske, Jürgen; Fischer, Andreas

2015-03-01

Polymer composite rotors are lightweight and offer great perspectives in high-speed applications such as turbo machinery. Currently, novel rotor structures and materials are investigated for the purpose of increasing machine efficiency and lifetime, as well as allowing for higher dynamic loads. However, due to the complexity of the composite materials an in-process measurement system is required. This allows for monitoring the evolution of damages under dynamic loads, for testing and predicting the structural integrity of composite rotors in process. In rotor design, it can be used for calibrating and improving models, simulating the dynamic behaviour of polymer composite rotors. The measurement system is to work non-invasive, offer micron uncertainty, as well as a high measurement rate of several tens of kHz. Furthermore, it must be applicable at high surface speeds and under technical vacuum. In order to fulfil these demands a novel laser distance measurement system was developed. It provides the angle resolved measurement of the biaxial deformation of a fibre-reinforced polymer composite rotor with micron uncertainty at surface speeds of more than 300 m/s. Furthermore, a simulation procedure combining a finite element model and a damage mechanics model is applied. A comparison of the measured data and the numerically calculated data is performed to validate the simulation towards rotor expansion. This validating procedure can be used for a model calibration in the future. The simulation procedure could be used to investigate different damage-test cases of the rotor, in order to define its structural behaviour without further experiments.

Convergent validity of the Integrated Visual and Auditory Continuous Performance Test (IVA+Plus): associations with working memory, processing speed, and behavioral ratings.

Science.gov (United States)

Arble, Eamonn; Kuentzel, Jeffrey; Barnett, Douglas

2014-05-01

Though the Integrated Visual and Auditory Continuous Performance Test (IVA + Plus) is commonly used by researchers and clinicians, few investigations have assessed its convergent and discriminant validity, especially with regard to its use with children. The present study details correlates of the IVA + Plus using measures of cognitive ability and ratings of child behavior (parent and teacher), drawing upon a sample of 90 psychoeducational evaluations. Scores from the IVA + Plus correlated significantly with the Working Memory and Processing Speed Indexes from the Fourth Edition of the Wechsler Intelligence Scales for Children (WISC-IV), though fewer and weaker significant correlations were seen with behavior ratings scales, and significant associations also occurred with WISC-IV Verbal Comprehension and Perceptual Reasoning. The overall pattern of relations is supportive of the validity of the IVA + Plus; however, general cognitive ability was associated with better performance on most of the primary scores of the IVA + Plus, suggesting that interpretation should take intelligence into account.

Can Social Learning Increase Learning Speed, Performance or Both?

NARCIS (Netherlands)

Heinerman, J.V.; Stork, J.; Rebolledo Coy, M.A.; Hubert, J.G.; Eiben, A.E.; Bartz-Beielstein, Thomas; Haasdijk, Evert

2017-01-01

Social learning enables multiple robots to share learned experiences while completing a task. The literature offers contradicting examples of its benefits; robots trained with social learning reach a higher performance, an increased learning speed, or both, compared to their individual learning

Effects of Partial Sleep Deprivation on Information Processing Speed in Adolescence.

Science.gov (United States)

Cohen-Zion, Mairav; Shabi, Adi; Levy, Sigal; Glasner, Laura; Wiener, Avigail

2016-04-01

Although chronic sleep loss is highly common among teens, few objective sleep studies have examined its effects on cognitive performance, and specifically on information processing speed (IPS), a measure of cognitive proficiency. Forty-five adolescents underwent four consecutive nights of monitored sleep restriction (6-6.5 hr/night) and four nights of sleep extension (10-10.5 hr/night), in counterbalanced order, and separated by a washout period. Following each sleep period, cognitive performance was assessed, at a fixed morning time, using a computerized neuropsychological battery including an IPS task, a timed test providing both accuracy and reaction time outcome measures. Overall IPS performance was poorer in the restricted when compared to the extended condition. Increasing task load and pace were associated with increased accuracy for both sleep conditions. However, a significant pace by load interaction effect was only found in the extended condition, with post hoc tests showing that for medium and hard loads, IPS accuracies were better with increasing pace of task. Differences in IPS reaction times were not found between the sleep conditions. In addition, sleep-related changes in IPS indices were correlated with changes in executive function, motor skill, and attention performance. Adolescents' ability to process information may be especially vulnerable to sleep loss. Under ideal sleep conditions, however, they seem to be able to achieve optimal performance, particularly on more challenging problems. The functional implications of these findings may be particularly relevant to teens, who are often sleep deprived and are constantly required to process academic, social, and emotional input.

Accounting for the speed shear in wind turbine power performance measurement

DEFF Research Database (Denmark)

Wagner, Rozenn; Courtney, Michael; Gottschall, Julia

2011-01-01

The current IEC standard for wind turbine power performance measurement only requires measurement of the wind speed at hub height assuming this wind speed to be representative for the whole rotor swept area. However, the power output of a wind turbine depends on the kinetic energy flux, which...... itself depends on the wind speed profile, especially for large turbines. Therefore, it is important to characterize the wind profile in front of the turbine, and this should be preferably achieved by measuring the wind speed over the vertical range between lower and higher rotor tips. In this paper, we...... describe an experiment in which wind speed profiles were measured in front of a multimegawatt turbine using a ground–based pulsed lidar. Ignoring the vertical shear was shown to overestimate the kinetic energy flux of these profiles, in particular for those deviating significantly from a power law profile...

Comparison of performances of full-speed turbine and half-speed turbine for nuclear power plants

International Nuclear Information System (INIS)

Wang Hu; Zhang Weihong; Zhang Qiang; Li Shaohua

2010-01-01

The steam turbines of nuclear power plants can be divided into the full-speed turbine and half-speed turbine. Different speed leads to differences in many aspects. Therefore, the rational speed is the key point in the selection of steam turbines. This paper contrasts the economy between the half-speed turbine and full-speed turbine, by calculating the relative internal efficiency of half-speed and full-speed steam turbines with the typical level of 1000 megawatt. At the same time, this paper also calculate the relative speed of high speed water drops in the last stage blade of half-speed turbine and full-speed turbine, to contrast the water erosion between the half-speed turbine and full-speed turbine. The results show that the relative internal efficiency of half-speed turbine is higher than that of the full-speed turbine, and that the security especially the ability of preventing water erosion of half-speed turbine is better than that of the full-speed turbine. (authors)

Effect of additional speed endurance training on performance and muscle adaptations

DEFF Research Database (Denmark)

Gunnarsson, Thomas; Christensen, Peter Møller; Holse, Kris

2012-01-01

PURPOSE: The present study examined the effect of additional speed-endurance training during the season on muscle adaptations and performance of trained soccer players. METHODS: Eighteen sub-elite soccer players performed one session with 6-9 30-s intervals at an intensity of 90-95 % ofmaximal...... intensity (speed endurance training; SET) a week for 5 weeks (SET-intervention). Before and after the SET-intervention the players carried out the Yo-Yo intermittent recovery level 2 (Yo- Yo IR2) test, a sprint test (10- and 30-m) and an agility test. In addition, seven of the players had a resting muscle...

A Quick Test of Cognitive Speed for Comparing Processing Speed to Differentiate Adult Psychiatric Referrals With and Without Attention-Deficit/Hyperactivity Disorders

OpenAIRE

Wiig, Elisabeth Hemmersam; Nielsen, Niels Peter

2012-01-01

Objective: This retrospective study used A Quick Test of Cognitive Speed (AQT) to compare processing speed and efficiency measures by adults with attention-deficit/hyperactivity disorder (ADHD) or non-ADHD psychiatric disorders and healthy controls.

Modelling Of Residual Stresses Induced By High Speed Milling Process

International Nuclear Information System (INIS)

Desmaison, Olivier; Mocellin, Katia; Jardin, Nicolas

2011-01-01

Maintenance processes used in heavy industries often include high speed milling operations. The reliability of the post-process material state has to be studied. Numerical simulation appears to be a very interesting way to supply an efficient residual stresses (RS) distribution prediction.Because the adiabatic shear band and the serrated chip shaping are features of the austenitic stainless steel high speed machining, a 2D high speed orthogonal cutting model is briefly presented. This finite element model, developed on Forge registered software, is based on data taken from Outeiro and al.'s paper [1]. A new behaviour law fully coupling Johnson-Cook's constitutive law and Latham and Cockcroft's damage model is detailed in this paper. It ensures results that fit those found in literature.Then, the numerical tools used on the 2D model are integrated to a 3D high speed milling model. Residual stresses distribution is analysed, on the surface and into the depth of the material. Various revolutions and passes of the two teeth hemispheric mill on the workpiece are simulated. Thus the sensitivity of the residual stresses generation to the cutting conditions can be discussed. In order to validate the 3D model, a comparison of the cutting forces measured by EDF R and D to those given by numerical simulations is achieved.

Grey Wolf based control for speed ripple reduction at low speed operation of PMSM drives.

Science.gov (United States)

Djerioui, Ali; Houari, Azeddine; Ait-Ahmed, Mourad; Benkhoris, Mohamed-Fouad; Chouder, Aissa; Machmoum, Mohamed

2018-03-01

Speed ripple at low speed-high torque operation of Permanent Magnet Synchronous Machine (PMSM) drives is considered as one of the major issues to be treated. The presented work proposes an efficient PMSM speed controller based on Grey Wolf (GW) algorithm to ensure a high-performance control for speed ripple reduction at low speed operation. The main idea of the proposed control algorithm is to propose a specific objective function in order to incorporate the advantage of fast optimization process of the GW optimizer. The role of GW optimizer is to find the optimal input controls that satisfy the speed tracking requirements. The synthesis methodology of the proposed control algorithm is detailed and the feasibility and performances of the proposed speed controller is confirmed by simulation and experimental results. The GW algorithm is a model-free controller and the parameters of its objective function are easy to be tuned. The GW controller is compared to PI one on real test bench. Then, the superiority of the first algorithm is highlighted. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Low visual information-processing speed and attention are predictors of fatigue in elementary and junior high school students.

Science.gov (United States)

Mizuno, Kei; Tanaka, Masaaki; Fukuda, Sanae; Yamano, Emi; Shigihara, Yoshihito; Imai-Matsumura, Kyoko; Watanabe, Yasuyoshi

2011-06-14

Fatigue is a common complaint among elementary and junior high school students, and is known to be associated with reduced academic performance. Recently, we demonstrated that fatigue was correlated with decreased cognitive function in these students. However, no studies have identified cognitive predictors of fatigue. Therefore, we attempted to determine independent cognitive predictors of fatigue in these students. We performed a prospective cohort study. One hundred and forty-two elementary and junior high school students without fatigue participated. They completed a variety of paper-and-pencil tests, including list learning and list recall tests, kana pick-out test, semantic fluency test, figure copying test, digit span forward test, and symbol digit modalities test. The participants also completed computerized cognitive tests (tasks A to E on the modified advanced trail making test). These cognitive tests were used to evaluate motor- and information-processing speed, immediate and delayed memory function, auditory and visual attention, divided and switching attention, retrieval of learned material, and spatial construction. One year after the tests, a questionnaire about fatigue (Japanese version of the Chalder Fatigue Scale) was administered to all the participants. After the follow-up period, we confirmed 40 cases of fatigue among 118 students. In multivariate logistic regression analyses adjusted for grades and gender, poorer performance on visual information-processing speed and attention tasks was associated with increased risk of fatigue. Reduced visual information-processing speed and poor attention are independent predictors of fatigue in elementary and junior high school students. © 2011 Mizuno et al; licensee BioMed Central Ltd.

Low visual information-processing speed and attention are predictors of fatigue in elementary and junior high school students

Directory of Open Access Journals (Sweden)

Yamano Emi

2011-06-01

Full Text Available Abstract Background Fatigue is a common complaint among elementary and junior high school students, and is known to be associated with reduced academic performance. Recently, we demonstrated that fatigue was correlated with decreased cognitive function in these students. However, no studies have identified cognitive predictors of fatigue. Therefore, we attempted to determine independent cognitive predictors of fatigue in these students. Methods We performed a prospective cohort study. One hundred and forty-two elementary and junior high school students without fatigue participated. They completed a variety of paper-and-pencil tests, including list learning and list recall tests, kana pick-out test, semantic fluency test, figure copying test, digit span forward test, and symbol digit modalities test. The participants also completed computerized cognitive tests (tasks A to E on the modified advanced trail making test. These cognitive tests were used to evaluate motor- and information-processing speed, immediate and delayed memory function, auditory and visual attention, divided and switching attention, retrieval of learned material, and spatial construction. One year after the tests, a questionnaire about fatigue (Japanese version of the Chalder Fatigue Scale was administered to all the participants. Results After the follow-up period, we confirmed 40 cases of fatigue among 118 students. In multivariate logistic regression analyses adjusted for grades and gender, poorer performance on visual information-processing speed and attention tasks was associated with increased risk of fatigue. Conclusions Reduced visual information-processing speed and poor attention are independent predictors of fatigue in elementary and junior high school students.

Sensitometric characteristics of D-, E- and F-speed dental radiographic films in manual and automatic processing

Directory of Open Access Journals (Sweden)

Jahangir Haghani DDS, MSc

2012-09-01

Full Text Available BACKGROUND AND AIM:The purpose of this study was to evaluatethe sensitometric characteristics of Ultraspeed,Ektaspeed Plus and Insight dental radiographic films using manual and automatic processing systems.METHODS:In this experimental invitro study, an aluminum step-wedge was used to construct characteristic curves forD-, E- and F-speed radiographic films (Kodak Eastman, Rochester, USA. All films were processed in Iranianprocessing solution (chemical industries Co., Iran, Tehran both manually and automatically in a period of six days.Unexposed films of three types were processed manually andautomatically to determine base plus fog density. Speedand film contrast were measured according to International Standard Organization definition.RESULTS:There was significant difference in density obtained with the D-, E- and F-speed films in both manually andautomatically processing systems (P < 0.001. There was significant difference in density obtained with the Ultraspeed andinsight films. There was no significant difference in contrast obtained with the D-, E- and F-speed films in both manuallyand automatically processing systems (P = 0.255 , P = 0.260. There was significant difference in speed obtained with theD-, E- and F-speed films in both manually and automatically processing systems (P = 0.034, P = 0.040.CONCLUSIONS:The choice of processing system canaffect radiographic characteristics. The F-speed film processed inautomatic system has greater speed in comparison with manualprocessing system, and it provides a further reduction inradiation exposure without detriment to image quality.

Assessing the benefits of napping and short rest breaks on processing speed in sleep-restricted adolescents.

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Lim, Julian; Lo, June C; Chee, Michael W L

2017-04-01

Achievement-oriented adolescents often study long hours under conditions of chronic sleep restriction, adversely affecting cognitive function. Here, we studied how napping and rest breaks (interleaved off-task periods) might ameliorate the negative effects of sleep restriction on processing speed. Fifty-seven healthy adolescents (26 female, age = 15-19 years) participated in a 15-day live-in protocol. All participants underwent sleep restriction (5 h time-in-bed), but were then randomized into two groups: one of these groups received a daily 1-h nap opportunity. Data from seven of the study days (sleep restriction days 1-5, and recovery days 1-2) are reported here. The Blocked Symbol Decoding Test, administered once a day, was used to assess time-on-task effects and the effects of rest breaks on processing speed. Controlling for baseline differences, participants who took a nap demonstrated faster speed of processing and greater benefit across testing sessions from practice. These participants were also affected significantly less by time-on-task effects. In contrast, participants who did not receive a nap benefited more from the rest breaks that were permitted between blocks of the test. Our results indicate that napping partially reverses the detrimental effects of sleep restriction on processing speed. However, rest breaks have a greater effect as a countermeasure against poor performance when sleep pressure is higher. These data add to the growing body of evidence showing the importance of sleep for good cognitive functioning in adolescents, and suggest that more frequent rest breaks might be important in situations where sleep loss is unavoidable. © 2017 European Sleep Research Society.

Chaotic home environment is associated with reduced infant processing speed under high task demands.

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Tomalski, Przemysław; Marczuk, Karolina; Pisula, Ewa; Malinowska, Anna; Kawa, Rafał; Niedźwiecka, Alicja

2017-08-01

Early adversity has profound long-term consequences for child development across domains. The effects of early adversity on structural and functional brain development were shown for infants under 12 months of life. However, the causal mechanisms of these effects remain relatively unexplored. Using a visual habituation task we investigated whether chaotic home environment may affect processing speed in 5.5 month-old infants (n=71). We found detrimental effects of chaos on processing speed for complex but not for simple visual stimuli. No effects of socio-economic status on infant processing speed were found although the sample was predominantly middle class. Our results indicate that chaotic early environment may adversely affect processing speed in early infancy, but only when greater cognitive resources need to be deployed. The study highlights an attractive avenue for research on the mechanisms linking home environment with the development of attention control. Copyright © 2017 Elsevier Inc. All rights reserved.

Genetic effects on information processing speed are moderated by age--converging results from three samples.

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Ising, M; Mather, K A; Zimmermann, P; Brückl, T; Höhne, N; Heck, A; Schenk, L A; Rujescu, D; Armstrong, N J; Sachdev, P S; Reppermund, S

2014-06-01

Information processing is a cognitive trait forming the basis of complex abilities like executive function. The Trail Making Test (TMT) is a well-established test of information processing with moderate to high heritability. Age of the individual also plays an important role. A number of genetic association studies with the TMT have been performed, which, however, did not consider age as a moderating factor. We report the results of genome-wide association studies (GWASs) on age-independent and age-dependent TMT performance in two population-representative community samples (Munich Antidepressant Response Signature, MARS: N1 = 540; Ludwig Maximilians University, LMU: N2 = 350). Age-dependent genome-wide findings were then evaluated in a third sample of healthy elderly subjects (Sydney Memory and Ageing Study, Sydney MAS: N3 = 448). While a meta-analysis on the GWAS findings did not reveal age-independent TMT associations withstanding correction for multiple testing, we found a genome-wide significant age-moderated effect between variants in the DSG1 gene region and TMT-A performance predominantly reflecting visual processing speed (rs2199301, P(meta-analysis) = 1.3 × 10(-7)). The direction of the interaction suggests for the minor allele a beneficial effect in younger adults turning into a detrimental effect in older adults. The detrimental effect of the missense single nucleotide polymorphism rs1426310 within the same DSG1 gene region could be replicated in Sydney MAS participants aged 70-79, but not in those aged 80 years and older, presumably a result of survivor bias. Our findings demonstrate opposing effects of DSG1 variants on information processing speed depending on age, which might be related to the complex processes that DSG1 is involved with, including cell adhesion and apoptosis. © 2014 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

The Moderating Effects of Decision-making Preference on M&A Integration Speed and Performance

DEFF Research Database (Denmark)

Uzelac, Boris; Bauer, Florian; Matzler, Kurt

2016-01-01

This paper illustrates the effects of post-merger integration speed on M&A performance and the moderating role of decision-making preferences. For a better understanding of the effects of integration speed, we separate the role of human and task integration speed. The results, obtained from...

Visual function and cognitive speed of processing mediate age-related decline in memory span and fluid intelligence.

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Clay, Olivio J; Edwards, Jerri D; Ross, Lesley A; Okonkwo, Ozioma; Wadley, Virginia G; Roth, David L; Ball, Karlene K

2009-06-01

To evaluate the relationship between sensory and cognitive decline, particularly with respect to speed of processing, memory span, and fluid intelligence. In addition, the common cause, sensory degradation and speed of processing hypotheses were compared. Structural equation modeling was used to investigate the complex relationships among age-related decrements in these areas. Cross-sectional data analyses included 842 older adult participants (M = 73 years). After accounting for age-related declines in vision and processing speed, the direct associations between age and memory span and between age and fluid intelligence were nonsignificant. Older age was associated with visual decline, which was associated with slower speed of processing, which in turn was associated with greater cognitive deficits. The findings support both the sensory degradation and speed of processing accounts of age-related, cognitive decline. Furthermore, the findings highlight positive aspects of normal cognitive aging in that older age may not be associated with a loss of fluid intelligence if visual sensory functioning and processing speed can be maintained.

Constant versus variable response signal delays in speed--accuracy trade-offs: effects of advance preparation for processing time.

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Miller, Jeff; Sproesser, Gudrun; Ulrich, Rolf

2008-07-01

In two experiments, we used response signals (RSs) to control processing time and trace out speed--accuracy trade-off(SAT) functions in a difficult perceptual discrimination task. Each experiment compared performance in blocks of trials with constant and, hence, temporally predictable RS lags against performance in blocks with variable, unpredictable RS lags. In both experiments, essentially equivalent SAT functions were observed with constant and variable RS lags. We conclude that there is little effect of advance preparation for a given processing time, suggesting that the discrimination mechanisms underlying SAT functions are driven solely by bottom-up information processing in perceptual discrimination tasks.

A study on the effect of flat plate friction resistance on speed performance prediction of full scale

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Park Dong-Woo

2015-01-01

Full Text Available Flat plate friction lines hare been used in the process to estimate speed performance of full-scale ships in model tests. The results of the previous studies showed considerable differences in determining form factors depending on changes in plate friction lines and Reynolds numbers. These differences had a great influence on estimation of speed performance of full-scale ships. This study- was conducted in two parts. In the first part, the scale effect of the form factor depending on change in the Reynolds number was studied based on CFD, in connection with three kinds of friction resistance curves: the ITTC-1957, the curve proposed by Grigson (1993; 1996, and the curve developed by Katsui et al (2005. In the second part, change in the form factor by three kinds of

Relationships among processing speed, working memory, and fluid intelligence in children.

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Fry, A F; Hale, S

2000-10-01

The present review focuses on three issues, (a) the time course of developmental increases in cognitive abilities; (b) the impact of age on individual differences in these abilities, and (c) the mechanisms by which developmental increases in different aspects of cognition affect each other. We conclude from our review of the literature that the development of processing speed, working memory, and fluid intelligence, all follow a similar time course, suggesting that all three abilities develop in concert. Furthermore, the strength of the correlation between speed and intelligence does not appear to change with age, and most of the effect of the age-related increase in speed on intelligence appears to be mediated through the effect of speed on working memory. Finally, most of the effect of the age-related improvement in working memory on intelligence is itself attributable to the effect of the increase in speed on working memory, providing evidence of a cognitive developmental cascade.

A reward semi-Markov process with memory for wind speed modeling

Science.gov (United States)

Petroni, F.; D'Amico, G.; Prattico, F.

2012-04-01

-order Markov chain with different number of states, and Weibull distribution. All this model use Markov chains to generate synthetic wind speed time series but the search for a better model is still open. Approaching this issue, we applied new models which are generalization of Markov models. More precisely we applied semi-Markov models to generate synthetic wind speed time series. The primary goal of this analysis is the study of the time history of the wind in order to assess its reliability as a source of power and to determine the associated storage levels required. In order to assess this issue we use a probabilistic model based on indexed semi-Markov process [4] to which a reward structure is attached. Our model is used to calculate the expected energy produced by a given turbine and its variability expressed by the variance of the process. Our results can be used to compare different wind farms based on their reward and also on the risk of missed production due to the intrinsic variability of the wind speed process. The model is used to generate synthetic time series for wind speed by means of Monte Carlo simulations and backtesting procedure is used to compare results on first and second oder moments of rewards between real and synthetic data. [1] A. Shamshad, M.A. Bawadi, W.M.W. Wan Hussin, T.A. Majid, S.A.M. Sanusi, First and second order Markov chain models for synthetic gen- eration of wind speed time series, Energy 30 (2005) 693-708. [2] H. Nfaoui, H. Essiarab, A.A.M. Sayigh, A stochastic Markov chain model for simulating wind speed time series at Tangiers, Morocco, Re- newable Energy 29 (2004) 1407-1418. [3] F. Youcef Ettoumi, H. Sauvageot, A.-E.-H. Adane, Statistical bivariate modeling of wind using first-order Markov chain and Weibull distribu- tion, Renewable Energy 28 (2003) 1787-1802. [4]F. Petroni, G. D'Amico, F. Prattico, Indexed semi-Markov process for wind speed modeling. To be submitted.

Processing speed training increases the efficiency of attentional resource allocation in young adults

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Wesley K Burge

2013-10-01

Full Text Available Cognitive training has been shown to improve performance on a range of tasks. However, the mechanisms underlying these improvements are still unclear. Given the wide range of transfer effects, it is likely that these effects are due to a factor common to a wide range of tasks. One such factor is a participant’s efficiency in allocating limited cognitive resources. The impact of a cognitive training program, Processing Speed Training (PST, on the allocation of resources to a set of visual tasks was measured using pupillometry in 10 young adults as compared to a control group of a 10 young adults (n = 20. PST is a well-studied computerized training program that involves identifying simultaneously presented central and peripheral stimuli. As training progresses, the task becomes increasingly more difficult, by including peripheral distracting stimuli and decreasing the duration of stimulus presentation. Analysis of baseline data confirmed that pupil diameter reflected cognitive effort. After training, participants randomized to PST used fewer attentional resources to perform complex visual tasks as compared to the control group. These pupil diameter data indicated that PST appears to increase the efficiency of attentional resource allocation. Increases in cognitive efficiency have been hypothesized to underlie improvements following experience with action video games, and improved cognitive efficiency has been hypothesized to underlie the benefits of processing speed training in older adults. These data reveal that these training schemes may share a common underlying mechanism of increasing cognitive efficiency in younger adults.

Verbal Working Memory in Older Adults: The Roles of Phonological Capacities and Processing Speed

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Nittrouer, Susan; Lowenstein, Joanna H.; Wucinich, Taylor; Moberly, Aaron C.

2016-01-01

Purpose: This study examined the potential roles of phonological sensitivity and processing speed in age-related declines of verbal working memory. Method: Twenty younger and 25 older adults with age-normal hearing participated. Two measures of verbal working memory were collected: digit span and serial recall of words. Processing speed was…

Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

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Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

2015-12-08

A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

Holistic processing of impossible objects: evidence from Garner's speeded-classification task.

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Freud, Erez; Avidan, Galia; Ganel, Tzvi

2013-12-18

Holistic processing, the decoding of the global structure of a stimulus while the local parts are not explicitly represented, is a basic characteristic of object perception. The current study was aimed to test whether such a representation could be created even for objects that violate fundamental principles of spatial organization, namely impossible objects. Previous studies argued that these objects cannot be represented holistically in long-term memory because they lack coherent 3D structure. Here, we utilized Garner's speeded classification task to test whether the perception of possible and impossible objects is mediated by similar holistic processing mechanisms. To this end, participants were asked to make speeded classifications of one object dimension while an irrelevant dimension was kept constant (baseline condition) or when this dimension varied (filtering condition). It is well accepted that ignoring the irrelevant dimension is impossible when holistic perception is mandatory, thus the extent of Garner interference in performance between the baseline and filtering conditions serves as an index of holistic processing. Critically, in Experiment 1, similar levels of Garner interference were found for possible and impossible objects implying holistic perception of both object types. Experiment 2 extended these results and demonstrated that even when depth information was explicitly processed, participants were still unable to process one dimension (width/depth) while ignoring the irrelevant dimension (depth/width, respectively). The results of Experiment 3 replicated the basic pattern found in Experiments 1 and 2 using a novel set of object exemplars. In Experiment 4, we used possible and impossible versions of the Penrose triangles in which information about impossibility is embedded in the internal elements of the objects which participant were explicitly asked to judge. As in Experiments 1-3, similar Garner interference was found for possible and

Speed endurance training is a powerful stimulus for physiological adaptations and performance improvements of athletes

DEFF Research Database (Denmark)

Iaia, F. M.; Bangsbo, Jens

2010-01-01

the oxidative capacity and improve intense short-duration/repeated high-intensity exercise performance lasting 30 s to 4 min, as it occurs in a number of sports. When combined with a basic volume of training including some aerobic high-intensity sessions, speed endurance training is also useful in enhancing......The present article reviews the physiological and performance effects of speed endurance training consisting of exercise bouts at near maximal intensities in already trained subjects. Despite a reduction in training volume, speed endurance training of endurance-trained athletes can maintain...... performance during longer events, e.g. 40 K cycling and 10 K running. Athletes in team sports involving intense exercise actions and endurance aspects can also benefit from performing speed endurance training. These improvements don't appear to depend on changes in maximum oxygen uptake (VO2max), muscle...

Subsurface damage mechanism of high speed grinding process in single crystal silicon revealed by atomistic simulations

International Nuclear Information System (INIS)

Li, Jia; Fang, Qihong; Zhang, Liangchi; Liu, Youwen

2015-01-01

Highlights: • Molecular dynamic model of nanoscale high speed grinding of silicon workpiece has been established. • The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation during high speed grinding process are thoroughly investigated. • Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle. • The hydrostatic stress and von Mises stress by the established analytical model are studied subsurface damage mechanism during nanoscale grinding. - Abstract: Three-dimensional molecular dynamics (MD) simulations are performed to investigate the nanoscale grinding process of single crystal silicon using diamond tool. The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation are studied. We also establish an analytical model to calculate several important stress fields including hydrostatic stress and von Mises stress for studying subsurface damage mechanism, and obtain the dislocation density on the grinding subsurface. The results show that a higher grinding velocity in machining brittle material silicon causes a larger chip and a higher temperature, and reduces subsurface damage. However, when grinding velocity is above 180 m s −1 , subsurface damage thickness slightly increases because a higher grinding speed leads to the increase in grinding force and temperature, which accelerate dislocation nucleation and motion. Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle, that provides valuable reference for machining nanometer devices. The von Mises stress and the hydrostatic stress play an important role in the grinding process, and explain the subsurface damage though dislocation mechanism under high

Topography of Slow Sigma Power during Sleep is Associated with Processing Speed in Preschool Children.

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Doucette, Margaret R; Kurth, Salome; Chevalier, Nicolas; Munakata, Yuko; LeBourgeois, Monique K

2015-11-04

Cognitive development is influenced by maturational changes in processing speed, a construct reflecting the rapidity of executing cognitive operations. Although cognitive ability and processing speed are linked to spindles and sigma power in the sleep electroencephalogram (EEG), little is known about such associations in early childhood, a time of major neuronal refinement. We calculated EEG power for slow (10-13 Hz) and fast (13.25-17 Hz) sigma power from all-night high-density electroencephalography (EEG) in a cross-sectional sample of healthy preschool children (n = 10, 4.3 ± 1.0 years). Processing speed was assessed as simple reaction time. On average, reaction time was 1409 ± 251 ms; slow sigma power was 4.0 ± 1.5 μV²; and fast sigma power was 0.9 ± 0.2 μV². Both slow and fast sigma power predominated over central areas. Only slow sigma power was correlated with processing speed in a large parietal electrode cluster (p power predicted faster reaction time. Our findings indicate regional correlates between sigma power and processing speed that are specific to early childhood and provide novel insights into the neurobiological features of the EEG that may underlie developing cognitive abilities.

Global Processing Speed as a Mediator of Developmental Changes in Children's Auditory Memory Span

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Ferguson, A.N.; Bowey, J.A.

2005-01-01

This study examined the role of global processing speed in mediating age increases in auditory memory span in 5- to 13-year-olds. Children were tested on measures of memory span, processing speed, single-word speech rate, phonological sensitivity, and vocabulary. Structural equation modeling supported a model in which age-associated increases in…

Capacity-speed relationships in prefrontal cortex.

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Vivek Prabhakaran

Full Text Available Working memory (WM capacity and WM processing speed are simple cognitive measures that underlie human performance in complex processes such as reasoning and language comprehension. These cognitive measures have shown to be interrelated in behavioral studies, yet the neural mechanism behind this interdependence has not been elucidated. We have carried out two functional MRI studies to separately identify brain regions involved in capacity and speed. Experiment 1, using a block-design WM verbal task, identified increased WM capacity with increased activity in right prefrontal regions, and Experiment 2, using a single-trial WM verbal task, identified increased WM processing speed with increased activity in similar regions. Our results suggest that right prefrontal areas may be a common region interlinking these two cognitive measures. Moreover, an overlap analysis with regions associated with binding or chunking suggest that this strategic memory consolidation process may be the mechanism interlinking WM capacity and WM speed.

The evaluation of speed skating helmet performance through peak linear and rotational accelerations.

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Karton, Clara; Rousseau, Philippe; Vassilyadi, Michael; Hoshizaki, Thomas Blaine

2014-01-01

Like many sports involving high speeds and body contact, head injuries are a concern for short track speed skating athletes and coaches. While the mandatory use of helmets has managed to nearly eliminate catastrophic head injuries such as skull fractures and cerebral haemorrhages, they may not be as effective at reducing the risk of a concussion. The purpose of this study was to evaluate the performance characteristics of speed skating helmets with respect to managing peak linear and peak rotational acceleration, and to compare their performance against other types of helmets commonly worn within the speed skating sport. Commercially available speed skating, bicycle and ice hockey helmets were evaluated using a three-impact condition test protocol at an impact velocity of 4 m/s. Two speed skating helmet models yielded mean peak linear accelerations at a low-estimated probability range for sustaining a concussion for all three impact conditions. Conversely, the resulting mean peak rotational acceleration values were all found close to the high end of a probability range for sustaining a concussion. A similar tendency was observed for the bicycle and ice hockey helmets under the same impact conditions. Speed skating helmets may not be as effective at managing rotational acceleration and therefore may not successfully protect the user against risks associated with concussion injuries.

Quantitative measurement of vocal fold vibration in male radio performers and healthy controls using high-speed videoendoscopy.

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Samantha Warhurst

Full Text Available Acoustic and perceptual studies show a number of differences between the voices of radio performers and controls. Despite this, the vocal fold kinematics underlying these differences are largely unknown. Using high-speed videoendoscopy, this study sought to determine whether the vocal vibration features of radio performers differed from those of non-performing controls.Using high-speed videoendoscopy, recordings of a mid-phonatory/i/ in 16 male radio performers (aged 25-52 years and 16 age-matched controls (aged 25-52 years were collected. Videos were extracted and analysed semi-automatically using High-Speed Video Program, obtaining measures of fundamental frequency (f0, open quotient and speed quotient. Post-hoc analyses of sound pressure level (SPL were also performed (n = 19. Pearson's correlations were calculated between SPL and both speed and open quotients.Male radio performers had a significantly higher speed quotient than their matched controls (t = 3.308, p = 0.005. No significant differences were found for f0 or open quotient. No significant correlation was found between either open or speed quotient with SPL.A higher speed quotient in male radio performers suggests that their vocal fold vibration was characterised by a higher ratio of glottal opening to closing times than controls. This result may explain findings of better voice quality, higher equivalent sound level and greater spectral tilt seen in previous research. Open quotient was not significantly different between groups, indicating that the durations of complete vocal fold closure were not different between the radio performers and controls. Further validation of these results is required to determine the aetiology of the higher speed quotient result and its implications for voice training and clinical management in performers.

Executive deficits, not processing speed relates to abnormalities in distinct prefrontal tracts in amyotrophic lateral sclerosis.

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Pettit, Lewis D; Bastin, Mark E; Smith, Colin; Bak, Thomas H; Gillingwater, Thomas H; Abrahams, Sharon

2013-11-01

, uncinate fasciculus and hippocampal portion of the cingulum bundles. Significant differences also emerged in the anterior corona radiata as well as in white matter underlying the superior, medial and inferior frontal gyri and the temporal gyri. Dual-task performance significantly correlated with fractional anisotropy measures in the middle frontal gyrus white matter and anterior corona radiata. Letter fluency indices significantly correlated with fractional anisotropy measures of the inferior frontal gyrus white matter and corpus callosum in addition to the corticospinal tracts and mean diffusivity measures in the white matter of the superior frontal gyrus. The current study demonstrates that cognitive impairment in amyotrophic lateral sclerosis is not due to generic slowing of processing speed. Moreover, different executive deficits are related to distinct prefrontal tract involvement in amyotrophic lateral sclerosis with dual-task impairment associating with dorsolateral prefrontal dysfunction and letter fluency showing greater dependence on inferolateral prefrontal dysfunction.

Individual Differences in the Speed of Facial Emotion Recognition Show Little Specificity but Are Strongly Related with General Mental Speed: Psychometric, Neural and Genetic Evidence

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Xinyang Liu

2017-08-01

Full Text Available Facial identity and facial expression processing are crucial socio-emotional abilities but seem to show only limited psychometric uniqueness when the processing speed is considered in easy tasks. We applied a comprehensive measurement of processing speed and contrasted performance specificity in socio-emotional, social and non-social stimuli from an individual differences perspective. Performance in a multivariate task battery could be best modeled by a general speed factor and a first-order factor capturing some specific variance due to processing emotional facial expressions. We further tested equivalence of the relationships between speed factors and polymorphisms of dopamine and serotonin transporter genes. Results show that the speed factors are not only psychometrically equivalent but invariant in their relation with the Catechol-O-Methyl-Transferase (COMT Val158Met polymorphism. However, the 5-HTTLPR/rs25531 serotonin polymorphism was related with the first-order factor of emotion perception speed, suggesting a specific genetic correlate of processing emotions. We further investigated the relationship between several components of event-related brain potentials with psychometric abilities, and tested emotion specific individual differences at the neurophysiological level. Results revealed swifter emotion perception abilities to go along with larger amplitudes of the P100 and the Early Posterior Negativity (EPN, when emotion processing was modeled on its own. However, after partialling out the shared variance of emotion perception speed with general processing speed-related abilities, brain-behavior relationships did not remain specific for emotion. Together, the present results suggest that speed abilities are strongly interrelated but show some specificity for emotion processing speed at the psychometric level. At both genetic and neurophysiological levels, emotion specificity depended on whether general cognition is taken into account

Individual Differences in the Speed of Facial Emotion Recognition Show Little Specificity but Are Strongly Related with General Mental Speed: Psychometric, Neural and Genetic Evidence

Science.gov (United States)

Liu, Xinyang; Hildebrandt, Andrea; Recio, Guillermo; Sommer, Werner; Cai, Xinxia; Wilhelm, Oliver

2017-01-01

Facial identity and facial expression processing are crucial socio-emotional abilities but seem to show only limited psychometric uniqueness when the processing speed is considered in easy tasks. We applied a comprehensive measurement of processing speed and contrasted performance specificity in socio-emotional, social and non-social stimuli from an individual differences perspective. Performance in a multivariate task battery could be best modeled by a general speed factor and a first-order factor capturing some specific variance due to processing emotional facial expressions. We further tested equivalence of the relationships between speed factors and polymorphisms of dopamine and serotonin transporter genes. Results show that the speed factors are not only psychometrically equivalent but invariant in their relation with the Catechol-O-Methyl-Transferase (COMT) Val158Met polymorphism. However, the 5-HTTLPR/rs25531 serotonin polymorphism was related with the first-order factor of emotion perception speed, suggesting a specific genetic correlate of processing emotions. We further investigated the relationship between several components of event-related brain potentials with psychometric abilities, and tested emotion specific individual differences at the neurophysiological level. Results revealed swifter emotion perception abilities to go along with larger amplitudes of the P100 and the Early Posterior Negativity (EPN), when emotion processing was modeled on its own. However, after partialling out the shared variance of emotion perception speed with general processing speed-related abilities, brain-behavior relationships did not remain specific for emotion. Together, the present results suggest that speed abilities are strongly interrelated but show some specificity for emotion processing speed at the psychometric level. At both genetic and neurophysiological levels, emotion specificity depended on whether general cognition is taken into account or not. These

Information processing speed as a mediator between psychosocial stress and global cognition in older adults.

Science.gov (United States)

Foong, Hui F; Hamid, Tengku A; Ibrahim, Rahimah; Haron, Sharifah A

2018-01-01

The link between psychosocial stress and cognitive function is complex, and previous studies have indicated that it may be mediated by processing speed. Therefore, the main aim of this study was to examine whether processing speed mediates the association between psychosocial stress and global cognition in older adults. Moreover, the moderating role of gender in this model is examined as well. The study included 2322 community-dwelling older adults in Malaysia who were randomly selected through a multistage proportional cluster random sampling technique. Global cognition construct was measured by the Mini-Mental State Examination and Montreal Cognitive Assessment; psychosocial stress construct was measured by perceived stress, depression, loneliness, and neuroticism; and processing speed was assessed by the Digit Symbol Substitution Test. Structural equation modelling was used to analyze the mediation and moderation tests. Processing speed was found to partially mediate the relationship between psychosocial stress and global cognition (β in the direct model = -0.15, P cognition was found to be significant in men only, whereas the association between processing speed and global cognition was significant in men and women. Psychosocial stress may increase the likelihood that older adults will experience poor processing capacity, which could reduce their higher level cognition. Results indicate that there is a need to develop processing capacity intervention programmes for psychologically distressed older adults to prevent them from suffering cognitive decline. © 2018 Japanese Psychogeriatric Society.

Measuring automatic retrieval: a comparison of implicit memory, process dissociation, and speeded response procedures.

Science.gov (United States)

Horton, Keith D; Wilson, Daryl E; Vonk, Jennifer; Kirby, Sarah L; Nielsen, Tina

2005-07-01

Using the stem completion task, we compared estimates of automatic retrieval from an implicit memory task, the process dissociation procedure, and the speeded response procedure. Two standard manipulations were employed. In Experiment 1, a depth of processing effect was found on automatic retrieval using the speeded response procedure although this effect was substantially reduced in Experiment 2 when lexical processing was required of all words. In Experiment 3, the speeded response procedure showed an advantage of full versus divided attention at study on automatic retrieval. An implicit condition showed parallel effects in each study, suggesting that implicit stem completion may normally provide a good estimate of automatic retrieval. Also, we replicated earlier findings from the process dissociation procedure, but estimates of automatic retrieval from this procedure were consistently lower than those from the speeded response procedure, except when conscious retrieval was relatively low. We discuss several factors that may contribute to the conflicting outcomes, including the evidence for theoretical assumptions and criterial task differences between implicit and explicit tests.

Relative association of processing speed, short-term memory and sustained attention with task on gait speed: a study of community-dwelling people 50 years and older.

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Killane, Isabelle; Donoghue, Orna A; Savva, George M; Cronin, Hilary; Kenny, Rose Anne; Reilly, Richard B

2014-11-01

For single gait tasks, associations have been reported between gait speed and cognitive domains. However, few studies have evaluated if this association is altered in dual gait tasks given gait speed changes with complexity and nature of task. We evaluated relative contributions of specific elements of cognitive function (including sustained attention and processing speed) to dual task gait speed in a nationally representative population of community-dwelling adults over 50 years. Gait speed was obtained using the GaitRite walkway during three gait tasks: single, cognitive (alternate letters), and motor (carrying a filled glass). Linear regression models, adjusted for covariates, were constructed to predict the relative contributions of seven neuropsychological tests to gait speed differences and to investigate gait task effects. The mean age and gait speed of the population (n = 4,431, 55% women) was 62.4 years (SD = 8.2) and 135.85 cm/s (SD = 20.20, single task), respectively. Poorer processing speed, short-term memory, and sustained attention were major cognitive contributors to slower gait speed for all gait tasks. Both dual gait tasks were robust to covariate adjustment and had a significant additional executive function element not found for the single gait task. For community-dwelling older adults processing speed, short-term memory and sustained attention were independently associated with gait speed for all gait tasks. Dual gait tasks were found to highlight specific executive function elements. This result forms a baseline value for dual task gait speed. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of information processing speed on learning, memory, and executive functioning in people living with HIV/AIDS.

Science.gov (United States)

Fellows, Robert P; Byrd, Desiree A; Morgello, Susan

2014-01-01

It is unclear whether or to what degree literacy, aging, and other neurologic abnormalities relate to cognitive deficits among people living with HIV/AIDS in the combined antiretroviral therapy (CART) era. The primary aim of this study was to simultaneously examine the association of age, HIV-associated motor abnormalities, major depressive disorder, and reading level with information processing speed, learning, memory, and executive functions, and to determine whether processing speed mediated any of the relationships between cognitive and noncognitive variables. Participants were 186 racially and ethnically diverse men and women living with HIV/AIDS who underwent comprehensive neurological, neuropsychological, and medical evaluations. Structural equation modeling was utilized to assess the extent to which information processing speed mediated the relationship between age, motor abnormalities, major depressive disorder, and reading level with other cognitive abilities. Age, motor dysfunction, reading level, and current major depressive disorder were all significantly associated with information processing speed. Information processing speed fully mediated the effects of age on learning, memory, and executive functioning and partially mediated the effect of major depressive disorder on learning and memory. The effect of motor dysfunction on learning and memory was fully mediated by processing speed. These findings provide support for information processing speed as a primary deficit, which may account, at least in part, for many of the other cognitive abnormalities recognized in complex HIV/AIDS populations. The association of age and information processing speed may account for HIV/aging synergies in the generation of CART-era cognitive abnormalities.

Effects of reading speed on second-language sentence processing

NARCIS (Netherlands)

Kaan, Edith; Ballantyne, Jocelyn C.; Wijnen, Frank

2014-01-01

To test the effects of reading speed on second-language (L2) sentence processing and the potential influence of conflicting native language word order, we compared advanced L2 learners of English with native English speakers on a self-paced reading task. L2 learners read faster overall than native

Is general intelligence little more than the speed of higher-order processing?

Science.gov (United States)

Schubert, Anna-Lena; Hagemann, Dirk; Frischkorn, Gidon T

2017-10-01

Individual differences in the speed of information processing have been hypothesized to give rise to individual differences in general intelligence. Consistent with this hypothesis, reaction times (RTs) and latencies of event-related potential have been shown to be moderately associated with intelligence. These associations have been explained either in terms of individual differences in some brain-wide property such as myelination, the speed of neural oscillations, or white-matter tract integrity, or in terms of individual differences in specific processes such as the signal-to-noise ratio in evidence accumulation, executive control, or the cholinergic system. Here we show in a sample of 122 participants, who completed a battery of RT tasks at 2 laboratory sessions while an EEG was recorded, that more intelligent individuals have a higher speed of higher-order information processing that explains about 80% of the variance in general intelligence. Our results do not support the notion that individuals with higher levels of general intelligence show advantages in some brain-wide property. Instead, they suggest that more intelligent individuals benefit from a more efficient transmission of information from frontal attention and working memory processes to temporal-parietal processes of memory storage. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

A fast-start pacing strategy speeds pulmonary oxygen uptake kinetics and improves supramaximal running performance.

Directory of Open Access Journals (Sweden)

Tiago Turnes

Full Text Available The focus of the present study was to investigate the effects of a fast-start pacing strategy on running performance and pulmonary oxygen uptake (VO2 kinetics at the upper boundary of the severe-intensity domain. Eleven active male participants (28±10 years, 70±5 kg, 176±6 cm, 57±4 mL/kg/min visited the laboratory for a series of tests that were performed until exhaustion: 1 an incremental test; 2 three laboratory test sessions performed at 95, 100 and 110% of the maximal aerobic speed; 3 two to four constant speed tests for the determination of the highest constant speed (HS that still allowed achieving maximal oxygen uptake; and 4 an exercise based on the HS using a higher initial speed followed by a subsequent decrease. To predict equalized performance values for the constant pace, the relationship between time and distance/speed through log-log modelling was used. When a fast-start was utilized, subjects were able to cover a greater distance in a performance of similar duration in comparison with a constant-pace performance (constant pace: 670 m±22%; fast-start: 683 m±22%; P = 0.029; subjects also demonstrated a higher exercise tolerance at a similar average speed when compared with constant-pace performance (constant pace: 114 s±30%; fast-start: 125 s±26%; P = 0.037. Moreover, the mean VO2 response time was reduced after a fast start (constant pace: 22.2 s±28%; fast-start: 19.3 s±29%; P = 0.025. In conclusion, middle-distance running performances with a duration of 2-3 min are improved and VO2 response time is faster when a fast-start is adopted.

The effects of casting speed on steel continuous casting process

Energy Technology Data Exchange (ETDEWEB)

Sadat, Mohammad; Honarvar Gheysari, Ali; Sadat, Saeid [Islamic Azad University, Department of Mechanics, Mashhad Branch, Mashhad (Iran, Islamic Republic of)

2011-12-15

A three dimensional simulation of molten steel flow, heat transfer and solidification in mold and ''secondary cooling zone'' of Continuous Casting machine was performed with consideration of standard k-{epsilon} model. For this purpose, computational fluid dynamics software, FLUENT was utilized. From the simulation standpoint, the main distinction between this work and preceding ones is that, the phase change process (solidification) and flow (turbulent in mold section and laminar in secondary cooling zone) have been coupled and solved jointly instead of dividing it into ''transient heat conduction'' and ''steady fluid flow'' that can lead to more realistic simulation. Determining the appropriate boundary conditions in secondary cooling zone is very complicated because of various forms of heat transfer involved, including natural and forced convection and simultaneous radiation heat transfer. The main objective of this work is to have better understanding of heat transfer and solidification in the continuous casting process. Also, effects of casting speed on heat flux and shell thickness and role of radiation in total heat transfer is discussed. (orig.)

Stroop performance in multiple sclerosis: information processing, selective attention, or executive functioning?

Science.gov (United States)

Macniven, J A B; Davis, C; Ho, M-Y; Bradshaw, C M; Szabadi, E; Constantinescu, C S

2008-09-01

Cognitive impairments in information processing speed, attention and executive functioning are widely reported in patients with multiple sclerosis (MS). Several studies have identified impaired performance on the Stroop test in people with MS, yet uncertainty remains over the cause of this phenomenon. In this study, 25 patients with MS were assessed with a neuropsychological test battery including a computerized Stroop test and a computerized test of information processing speed, the Graded Conditional Discrimination Tasks (GCDT). The patient group was compared with an individually age, sex and estimated premorbid IQ-matched healthy control group. The patients' reaction times (RTs) were significantly longer than those of the controls on all Stroop test trials and there was a significantly enhanced absolute (RT(incongruent)-RT(neutral)) and relative (100 x [RT(incongruent)-RT(neutral)]/RT(neutral)) Stroop interference effect for the MS group. The linear function relating RT to stimulus complexity in the GCDT was significantly steeper in the patient group, indicating slowed information processing. The results are discussed with reference to the difference engine model, a theory of diversity in speeded cognition. It is concluded that, in the assessment of people with MS, great caution must be used in the interpretation of performance on neuropsychological tests which rely on RT as the primary measure.

Parameter analysis for speed skating performance

NARCIS (Netherlands)

van der Kruk, E.

2018-01-01

Speed skating is a rather special form of locomotion. While in most types of human locomotion, humans generate forces by pushing against the environment in the opposite direction of motion, in speed skating the skater pushes sideward to propel himself forward; Insight in the details of the technique

Low-Altitude and Slow-Speed Small Target Detection Based on Spectrum Zoom Processing

Directory of Open Access Journals (Sweden)

Xuwang Zhang

2018-01-01

Full Text Available This paper proposes a spectrum zoom processing based target detection algorithm for detecting the weak echo of low-altitude and slow-speed small (LSS targets in heavy ground clutter environments, which can be used to retrofit the existing radar systems. With the existing range-Doppler frequency images, the proposed method firstly concatenates the data from the same Doppler frequency slot of different images and then applies the spectrum zoom processing. After performing the clutter suppression, the target detection can be finally implemented. Through the theoretical analysis and real data verification, it is shown that the proposed algorithm can obtain a preferable spectrum zoom result and improve the signal-to-clutter ratio (SCR with a very low computational load.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

OpenAIRE

Dhandapani, N. V.; Thangarasu, V. S.; Sureshkannan, G.

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the...

Localized atrophy of the thalamus and slowed cognitive processing speed in MS patients.

Science.gov (United States)

Bergsland, Niels; Zivadinov, Robert; Dwyer, Michael G; Weinstock-Guttman, Bianca; Benedict, Ralph Hb

2016-09-01

Deep gray matter (DGM) atrophy is common in multiple sclerosis (MS), but no studies have investigated surface-based structure changes over time with respect to healthy controls (HCs). Moreover, the relationship between cognition and the spatio-temporal evolution of DGM atrophy is poorly understood. To explore DGM structural differences between MS and HCs over time in relation to neuropsychological (NP) outcomes. The participants were 44 relapsing-remitting and 20 secondary progressive MS patients and 22 HCs. All were scanned using 3T magnetic resonance imaging (MRI) at baseline and 3-year follow-up. NP examination emphasized consensus standard tests of processing speed and memory. We performed both volumetric and shape analysis of DGM structures and assessed their relationships with cognition. Compared to HCs, MS patients presented with significantly smaller DGM volumes. For the thalamus and caudate, differences in shape were mostly localized along the lateral ventricles. NP outcomes were related to both volume and shape of the DGM structures. Over 3 years, decreased cognitive processing speed was related to localized atrophy on the anterior and superior surface of the left thalamus. These findings highlight the role of atrophy in the anterior nucleus of the thalamus and its relation to cognitive decline in MS. © The Author(s), 2015.

High-speed vector-processing system of the MELCOM-COSMO 900II

Energy Technology Data Exchange (ETDEWEB)

Masuda, K; Mori, H; Fujikake, J; Sasaki, Y

1983-01-01

Progress in scientific and technical calculations has lead to a growing demand for high-speed vector calculations. Mitsubishi electric has developed an integrated array processor and automatic-vectorizing fortran compiler as an option for the MELCOM-COSMO 900II computer system. This facilitates the performance of vector calculations and matrix calculations, achieving significant gains in cost-effectiveness. The article outlines the high-speed vector system, includes discussion of compiler structuring, and cites examples of effective system application. 1 reference.

Processing Speed and Intelligence as Predictors of School Achievement: Mediation or Unique Contribution?

Science.gov (United States)

Dodonova, Yulia A.; Dodonov, Yury S.

2012-01-01

The relationships between processing speed, intelligence, and school achievement were analyzed on a sample of 184 Russian 16-year-old students. Two speeded tasks required the discrimination of simple geometrical shapes and the recognition of the presented meaningless figures. Raven's Advanced Progressive Matrices and the verbal subtests of…

Constant versus variable response signal delays in speed accuracy trade-offs : Effects of advance preparation for processing time

OpenAIRE

Miller, Jeff; Sproesser, Gudrun; Ulrich, Rolf

2008-01-01

In two experiments, we used response signals (RSs) to control processing time and trace out speed accuracy trade-off (SAT) functions in a difficult perceptual discrimination task. Each experiment compared performance in blocks of trials with constant and, hence, temporally predictable RS lags against performance in blocks with variable, unpredictable RS lags. In both experiments, essentially equivalent SAT functions were observed with constant and variable RS lags. We conclude that there is l...

White matter and information processing speed following treatment with cranial-spinal radiation for pediatric brain tumor.

Science.gov (United States)

Scantlebury, Nadia; Bouffet, Eric; Laughlin, Suzanne; Strother, Douglas; McConnell, Dina; Hukin, Juliette; Fryer, Christopher; Laperriere, Normand; Montour-Proulx, Isabelle; Keene, Daniel; Fleming, Adam; Jabado, Nada; Liu, Fang; Riggs, Lily; Law, Nicole; Mabbott, Donald J

2016-05-01

We compared the structure of specific white matter tracts and information processing speed between children treated for posterior fossa tumors with cranial-spinal radiation (n = 30), or with surgery +/- focal radiation (n = 29), and healthy children (n = 37). Probabilistic diffusion tensor imaging (DTI) tractography was used to delineate the inferior longitudinal fasciculi, optic radiation, inferior frontal occipital fasciculi, and uncinate fasciculi bilaterally. Information processing speed was measured using the coding and symbol search subtests of the Wechsler Intelligence Scales, and visual matching, pair cancellation, and rapid picture naming subtests of the Woodcock-Johnson Test of Cognitive Ability, 3rd revision. We examined group differences using repeated measures MANOVAs and path analyses were used to test the relations between treatment, white matter structure of the tracts, and information processing speed. DTI indices of the optic radiations, the inferior longitudinal fasciculi, and the inferior fronto-occipital fasciculi differed between children treated with cranial-spinal radiation and children treated with surgery +/- focal radiation, and healthy controls (p = .045). Children treated with cranial-spinal radiation also exhibited lower processing speed scores relative to healthy control subjects (p = .002). Notably, we observed that group differences in information processing speed were related to the structure of the right optic radiation (p = .002). We show that cranial-spinal radiation may have a negative impact on information processing speed via insult to the right optic radiations. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Topography of Slow Sigma Power during Sleep is Associated with Processing Speed in Preschool Children

Directory of Open Access Journals (Sweden)

Margaret R. Doucette

2015-11-01

Full Text Available Cognitive development is influenced by maturational changes in processing speed, a construct reflecting the rapidity of executing cognitive operations. Although cognitive ability and processing speed are linked to spindles and sigma power in the sleep electroencephalogram (EEG, little is known about such associations in early childhood, a time of major neuronal refinement. We calculated EEG power for slow (10–13 Hz and fast (13.25–17 Hz sigma power from all-night high-density electroencephalography (EEG in a cross-sectional sample of healthy preschool children (n = 10, 4.3 ± 1.0 years. Processing speed was assessed as simple reaction time. On average, reaction time was 1409 ± 251 ms; slow sigma power was 4.0 ± 1.5 μV2; and fast sigma power was 0.9 ± 0.2 μV2. Both slow and fast sigma power predominated over central areas. Only slow sigma power was correlated with processing speed in a large parietal electrode cluster (p < 0.05, r ranging from −0.6 to −0.8, such that greater power predicted faster reaction time. Our findings indicate regional correlates between sigma power and processing speed that are specific to early childhood and provide novel insights into the neurobiological features of the EEG that may underlie developing cognitive abilities.

Analysis of Wind Speed Forecasting Error Effects on Automatic Generation Control Performance

Directory of Open Access Journals (Sweden)

H. Rajabi Mashhadi

2014-09-01

Full Text Available The main goal of this paper is to study statistical indices and evaluate AGC indices in power system which has large penetration of the WTGs. Increasing penetration of wind turbine generations, needs to study more about impacts of it on power system frequency control. Frequency control is changed with unbalancing real-time system generation and load . Also wind turbine generations have more fluctuations and make system more unbalance. Then AGC loop helps to adjust system frequency and the scheduled tie-line powers. The quality of AGC loop is measured by some indices. A good index is a proper measure shows the AGC performance just as the power system operates. One of well-known measures in literature which was introduced by NERC is Control Performance Standards(CPS. Previously it is claimed that a key factor in CPS index is related to standard deviation of generation error, installed power and frequency response. This paper focuses on impact of a several hours-ahead wind speed forecast error on this factor. Furthermore evaluation of conventional control performances in the power systems with large-scale wind turbine penetration is studied. Effects of wind speed standard deviation and also degree of wind farm penetration are analyzed and importance of mentioned factor are criticized. In addition, influence of mean wind speed forecast error on this factor is investigated. The study system is a two area system which there is significant wind farm in one of those. The results show that mean wind speed forecast error has considerable effect on AGC performance while the mentioned key factor is insensitive to this mean error.

Practical End-to-End Performance Testing Tool for High Speed 3G-Based Networks

Science.gov (United States)

Shinbo, Hiroyuki; Tagami, Atsushi; Ano, Shigehiro; Hasegawa, Toru; Suzuki, Kenji

High speed IP communication is a killer application for 3rd generation (3G) mobile systems. Thus 3G network operators should perform extensive tests to check whether expected end-to-end performances are provided to customers under various environments. An important objective of such tests is to check whether network nodes fulfill requirements to durations of processing packets because a long duration of such processing causes performance degradation. This requires testers (persons who do tests) to precisely know how long a packet is hold by various network nodes. Without any tool's help, this task is time-consuming and error prone. Thus we propose a multi-point packet header analysis tool which extracts and records packet headers with synchronized timestamps at multiple observation points. Such recorded packet headers enable testers to calculate such holding durations. The notable feature of this tool is that it is implemented on off-the shelf hardware platforms, i.e., lap-top personal computers. The key challenges of the implementation are precise clock synchronization without any special hardware and a sophisticated header extraction algorithm without any drop.

Open | SpeedShop: An Open Source Infrastructure for Parallel Performance Analysis

Directory of Open Access Journals (Sweden)

Martin Schulz

2008-01-01

Full Text Available Over the last decades a large number of performance tools has been developed to analyze and optimize high performance applications. Their acceptance by end users, however, has been slow: each tool alone is often limited in scope and comes with widely varying interfaces and workflow constraints, requiring different changes in the often complex build and execution infrastructure of the target application. We started the Open | SpeedShop project about 3 years ago to overcome these limitations and provide efficient, easy to apply, and integrated performance analysis for parallel systems. Open | SpeedShop has two different faces: it provides an interoperable tool set covering the most common analysis steps as well as a comprehensive plugin infrastructure for building new tools. In both cases, the tools can be deployed to large scale parallel applications using DPCL/Dyninst for distributed binary instrumentation. Further, all tools developed within or on top of Open | SpeedShop are accessible through multiple fully equivalent interfaces including an easy-to-use GUI as well as an interactive command line interface reducing the usage threshold for those tools.

High-speed cineradiographies acquisition and processing

International Nuclear Information System (INIS)

Kahn, E.; Nourrissat, Yves; Viguier, Philippe

A high-speed cineradiography installation provides dimensional informations recorded either on a film, or on a magnetic tape. In the event of the film, the imperfection of our visual sense leads us to look for a method of measurement which allows us to extract the information from a noisy image; the association of an optical flying spot scanner with a computer is adapted to this use and allows us, for instance, to determine the inside and outside diameters of a sphere during its implosion. On the other hand, the radiographic recording on magnetic tape is processed, after numerisation by the computer, in the same way as the numeric tape generated after the optical scanner. We compare the results achieved by the two recording methods [fr

Task-relevant cognitive and motor functions are prioritized during prolonged speed-accuracy motor task performance.

Science.gov (United States)

Solianik, Rima; Satas, Andrius; Mickeviciene, Dalia; Cekanauskaite, Agne; Valanciene, Dovile; Majauskiene, Daiva; Skurvydas, Albertas

2018-06-01

This study aimed to explore the effect of prolonged speed-accuracy motor task on the indicators of psychological, cognitive, psychomotor and motor function. Ten young men aged 21.1 ± 1.0 years performed a fast- and accurate-reaching movement task and a control task. Both tasks were performed for 2 h. Despite decreased motivation, and increased perception of effort as well as subjective feeling of fatigue, speed-accuracy motor task performance improved during the whole period of task execution. After the motor task, the increased working memory function and prefrontal cortex oxygenation at rest and during conflict detection, and the decreased efficiency of incorrect response inhibition and visuomotor tracking were observed. The speed-accuracy motor task increased the amplitude of motor-evoked potentials, while grip strength was not affected. These findings demonstrate that to sustain the performance of 2-h speed-accuracy task under conditions of self-reported fatigue, task-relevant functions are maintained or even improved, whereas less critical functions are impaired.

Processing speed can monitor stimulant-medication effects in adults with attention deficit disorder with hyperactivity.

Science.gov (United States)

Nielsen, Niels Peter; Wiig, Elisabeth H; Bäck, Svante; Gustafsson, Jan

2017-05-01

Treatment responses to methylphenidate by adults with ADHD are generally monitored against DSM-IV/DSM-V symptomatology, rating scales or interviews during reviews. To evaluate the use of single- and dual-dimension processing-speed and efficiency measures to monitor the effects of pharmacological treatment with methylphenidate after a short period off medication. A Quick Test of Cognitive Speed (AQT) monitored the effects of immediate-release methylphenidate in 40 previously diagnosed and medicated adults with ADHD. Processing speed was evaluated with prior prescription medication, without medication after a 2-day period off ADHD medication, and with low-dose (10/20 mg) and high-dose (20/40 mg) methylphenidate hydrochloride (Medikinet IR). Thirty-three participants responded to the experimental treatments. One-way ANOVA with post-hoc analysis (Scheffe) indicated significant main effects for single dimension colour and form and dual-dimension colour-form naming. Post-hoc analysis indicated statistical differences between the no- and high-dose medication conditions for colour and form, measures of perceptual speed. For colour-form naming, a measure of cognitive speed, there was a significant difference between no- and low-dose medication and between no- and high-dose medications, but not between low- and high-dose medications. Results indicated that the AQT tests effectively monitored incremental effects of the methylphenidate dose on processing speed after a 2-day period off medication. Thus, perceptual (colour and form) and cognitive speed (two-dimensional colour-form naming) and processing efficiency (lowered shift costs) increased measurably with high-dose medication. These preliminary findings warrant validation with added measures of associated behavioural and cognitive changes.

Semiconductor optical amplifier-based all-optical gates for high-speed optical processing

DEFF Research Database (Denmark)

Stubkjær, Kristian

2000-01-01

Semiconductor optical amplifiers are useful building blocks for all-optical gates as wavelength converters and OTDM demultiplexers. The paper reviews the progress from simple gates using cross-gain modulation and four-wave mixing to the integrated interferometric gates using cross-phase modulation....... These gates are very efficient for high-speed signal processing and open up interesting new areas, such as all-optical regeneration and high-speed all-optical logic functions...

Information processing speed mediates the relationship between white matter and general intelligence in schizophrenia.

Science.gov (United States)

Alloza, Clara; Cox, Simon R; Duff, Barbara; Semple, Scott I; Bastin, Mark E; Whalley, Heather C; Lawrie, Stephen M

2016-08-30

Several authors have proposed that schizophrenia is the result of impaired connectivity between specific brain regions rather than differences in local brain activity. White matter abnormalities have been suggested as the anatomical substrate for this dysconnectivity hypothesis. Information processing speed may act as a key cognitive resource facilitating higher order cognition by allowing multiple cognitive processes to be simultaneously available. However, there is a lack of established associations between these variables in schizophrenia. We hypothesised that the relationship between white matter and general intelligence would be mediated by processing speed. White matter water diffusion parameters were studied using Tract-based Spatial Statistics and computed within 46 regions-of-interest (ROI). Principal component analysis was conducted on these white matter ROI for fractional anisotropy (FA) and mean diffusivity, and on neurocognitive subtests to extract general factors of white mater structure (gFA, gMD), general intelligence (g) and processing speed (gspeed). There was a positive correlation between g and gFA (r= 0.67, p =0.001) that was partially and significantly mediated by gspeed (56.22% CI: 0.10-0.62). These findings suggest a plausible model of structure-function relations in schizophrenia, whereby white matter structure may provide a neuroanatomical substrate for general intelligence, which is partly supported by speed of information processing. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Performance evaluation of a high-speed switched network for PACS

Science.gov (United States)

Zhang, Randy H.; Tao, Wenchao; Huang, Lu J.; Valentino, Daniel J.

1998-07-01

We have replaced our shared-media Ethernet and FDDI network with a multi-tiered, switched network using OC-12 (622 Mbps) ATM for the network backbone, OC3 (155 Mbps) connections to high-end servers and display workstations, and switched 100/10 Mbps Ethernet for workstations and desktop computers. The purpose of this research was to help PACS designers and implementers understand key performance factors in a high- speed switched network by characterizing and evaluating its image delivery performance, specifically, the performance of socket-based TCP (Transmission Control Protocol) and DICOM 3.0 communications. A test network within the UCLA Clinical RIS/PACS was constructed using Sun UltraSPARC-II machines with ATM, Fast Ethernet, and Ethernet network interfaces. To identify performance bottlenecks, we evaluated network throughput for memory to memory, memory to disk, disk to memory, and disk to disk transfers. To evaluate the effect of file size, tests involving disks were further divided using sizes of small (514 KB), medium (8 MB), and large (16 MB) files. The observed maximum throughput for various network configurations using the TCP protocol was 117 Mbps for memory to memory and 88 MBPS for memory to disk. For disk to memory, the peak throughput was 98 Mbps using small files, 114 Mbps using medium files, and 116 Mbps using large files. The peak throughput for disk to disk became 64 Mbps using small files and 96 Mbps using medium and large files. The peak throughput using the DICOM 3.0 protocol was substantially lower in all categories. The measured throughput varied significantly among the tests when TCP socket buffer was raised above the default value. The optimal buffer size was approximately 16 KB or the TCP protocol and around 256 KB for the DICOM protocol. The application message size also displayed distinctive effects on network throughput when the TCP socket buffer size was varied. The throughput results for Fast Ethernet and Ethernet were expectedly

Best Speed Fit EDF Scheduling for Performance Asymmetric Multiprocessors

Directory of Open Access Journals (Sweden)

Peng Wu

2017-01-01

Full Text Available In order to improve the performance of a real-time system, asymmetric multiprocessors have been proposed. The benefits of improved system performance and reduced power consumption from such architectures cannot be fully exploited unless suitable task scheduling and task allocation approaches are implemented at the operating system level. Unfortunately, most of the previous research on scheduling algorithms for performance asymmetric multiprocessors is focused on task priority assignment. They simply assign the highest priority task to the fastest processor. In this paper, we propose BSF-EDF (best speed fit for earliest deadline first for performance asymmetric multiprocessor scheduling. This approach chooses a suitable processor rather than the fastest one, when allocating tasks. With this proposed BSF-EDF scheduling, we also derive an effective schedulability test.

Resting State Default Mode Network Connectivity, Dual Task Performance, Gait Speed, and Postural Sway in Older Adults with Mild Cognitive Impairment.

Science.gov (United States)

Crockett, Rachel A; Hsu, Chun Liang; Best, John R; Liu-Ambrose, Teresa

2017-01-01

Aging is associated with an increased risk of falling. In particular, older adults with mild cognitive impairment (MCI) are more vulnerable to falling compared with their healthy counterparts. Major contributors to this increased falls risk include a decline in dual task performance, gait speed, and postural sway. Recent evidence highlights the potential influence of the default mode network (DMN), the frontoparietal network (FPN), and the supplementary motor area (SMA) on dual task performance, gait speed, and postural sway. The DMN is active during rest and deactivates during task-oriented processes, to maintain attention and stay on task. The FPN and SMA are involved in top-down attentional control, motor planning, and motor execution. The DMN shows less deactivation during task in older adults with MCI. This lack of deactivation is theorized to increase competition for resources between the DMN and task-related brain regions (e.g., the FPN and SMA), increasing distraction from the task and reducing task performance. However, no study has yet investigated the relationship between the between-network connectivity of the DMN with these regions and dual task walking, gait speed or postural sway. We hypothesized that greater functional connectivity both within the DMN and between DMN-FPN and DMN-SMA, will be associated with poorer performance during dual task walking, slower gait speed, and greater postural sway in older adults with MCI. Forty older adults with MCI were measured on a dual task-walking paradigm, gait speed over a 4-m walk, and postural sway using a sway-meter. Greater within-DMN connectivity was significantly correlated with poorer dual task performance. Furthermore, greater inter-network connectivity between the DMN and SMA was significantly correlated with slower gait speed and greater postural sway on the eyes open floor sway task. Thus, greater resting state DMN functional connectivity may be an underlying neural mechanism for reduced dual task

Influence of closed skill and open skill warm-ups on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sport athletes.

Science.gov (United States)

Gabbett, Tim J; Sheppard, Jeremy M; Pritchard-Peschek, Kellie R; Leveritt, Michael D; Aldred, Murry J

2008-09-01

In this study, we evaluated the efficacy of two different dynamic warm-up conditions, one that was inclusive of open skills (i.e., reactive movements) and one that included only preplanned dynamic activities (i.e., closed skills) on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sport athletes. Fourteen (six male, eight female) junior (mean +/- SD age, 16.3 +/- 0.7 year) basketball players participated in this study. Testing was conducted on 2 separate days using a within-subjects cross-over study design. Each athlete performed a standardized 7-minute warm-up consisting of general dynamic movements and stretching. After the general warm-up, athletes were randomly allocated into one of two groups that performed a dynamic 15-minute warm-up consisting entirely of open or closed skills. Each of the warm-up conditions consisted of five activities of 3 minute duration. At the completion of the warm-up protocol, players completed assessments of reactive agility, speed (5-, 10-, and 20-m sprints), change of direction speed (T-test), and vertical jump. No significant differences (p > 0.05) were detected among warm-up conditions for speed, vertical jump, change of direction speed, and reactive agility performances. The results of this study demonstrate that either open skill or closed skill warm-ups can be used effectively for team sport athletes without compromising performance on open skill and closed skill tasks.

HIGH PERFORMANCE PHOTOGRAMMETRIC PROCESSING ON COMPUTER CLUSTERS

Directory of Open Access Journals (Sweden)

V. N. Adrov

2012-07-01

Full Text Available Most cpu consuming tasks in photogrammetric processing can be done in parallel. The algorithms take independent bits as input and produce independent bits as output. The independence of bits comes from the nature of such algorithms since images, stereopairs or small image blocks parts can be processed independently. Many photogrammetric algorithms are fully automatic and do not require human interference. Photogrammetric workstations can perform tie points measurements, DTM calculations, orthophoto construction, mosaicing and many other service operations in parallel using distributed calculations. Distributed calculations save time reducing several days calculations to several hours calculations. Modern trends in computer technology show the increase of cpu cores in workstations, speed increase in local networks, and as a result dropping the price of the supercomputers or computer clusters that can contain hundreds or even thousands of computing nodes. Common distributed processing in DPW is usually targeted for interactive work with a limited number of cpu cores and is not optimized for centralized administration. The bottleneck of common distributed computing in photogrammetry can be in the limited lan throughput and storage performance, since the processing of huge amounts of large raster images is needed.

Pacing and Performance in Competitive Middle-Distance Speed Skating

Science.gov (United States)

Muehlbauer, Thomas; Schindler, Christian; Panzer, Stefan

2010-01-01

Data from speed skating during World Cup 1,500-m middle-distance races were analyzed to (a) determine the time/velocity distribution during the race and (b) assess the impact of time spent in several race sectors on performance outcome. Absolute and relative sector times for the first 300 m (S1) and the following three 400-m laps (S2-S4) and their…

Processing speed and working memory training in multiple sclerosis: a double-blind randomized controlled pilot study.

Science.gov (United States)

Hancock, Laura M; Bruce, Jared M; Bruce, Amanda S; Lynch, Sharon G

2015-01-01

Between 40-65% of multiple sclerosis patients experience cognitive deficits, with processing speed and working memory most commonly affected. This pilot study investigated the effect of computerized cognitive training focused on improving processing speed and working memory. Participants were randomized into either an active or a sham training group and engaged in six weeks of training. The active training group improved on a measure of processing speed and attention following cognitive training, and data trended toward significance on measures of other domains. Results provide preliminary evidence that cognitive training with multiple sclerosis patients may produce moderate improvement in select areas of cognitive functioning.

Keep calm and carry on: improved frustration tolerance and processing speed by transcranial direct current stimulation (tDCS.

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Christian Plewnia

Full Text Available Cognitive control (CC of attention is a major prerequisite for effective information processing. Emotional distractors can bias and impair goal-directed deployment of attentional resources. Frustration-induced negative affect and cognition can act as internal distractors with negative impact on task performance. Consolidation of CC may thus support task-oriented behavior under challenging conditions. Recently, transcranial direct current stimulation (tDCS has been put forward as an effective tool to modulate CC. Particularly, anodal, activity enhancing tDCS to the left dorsolateral prefrontal cortex (dlPFC can increase insufficient CC in depression as indicated by a reduction of attentional biases induced by emotionally salient stimuli. With this study, we provide first evidence that, compared to sham stimulation, tDCS to the left dlPFC enhances processing speed measured by an adaptive version of the Paced Auditory Serial Addition Task (PASAT that is typically thwarted by frustration. Notably, despite an even larger amount of error-related negative feedback, the task-induced upset was suppressed in the group receiving anodal tDCS. Moreover, inhibition of task-related negative affect was correlated with performance gains, suggesting a close link between enhanced processing speed and consolidation of CC by tDCS. Together, these data provide first evidence that activity enhancing anodal tDCS to the left dlPFC can support focused cognitive processing particularly when challenged by frustration-induced negative affect.

Keep calm and carry on: improved frustration tolerance and processing speed by transcranial direct current stimulation (tDCS).

Science.gov (United States)

Plewnia, Christian; Schroeder, Philipp A; Kunze, Roland; Faehling, Florian; Wolkenstein, Larissa

2015-01-01

Cognitive control (CC) of attention is a major prerequisite for effective information processing. Emotional distractors can bias and impair goal-directed deployment of attentional resources. Frustration-induced negative affect and cognition can act as internal distractors with negative impact on task performance. Consolidation of CC may thus support task-oriented behavior under challenging conditions. Recently, transcranial direct current stimulation (tDCS) has been put forward as an effective tool to modulate CC. Particularly, anodal, activity enhancing tDCS to the left dorsolateral prefrontal cortex (dlPFC) can increase insufficient CC in depression as indicated by a reduction of attentional biases induced by emotionally salient stimuli. With this study, we provide first evidence that, compared to sham stimulation, tDCS to the left dlPFC enhances processing speed measured by an adaptive version of the Paced Auditory Serial Addition Task (PASAT) that is typically thwarted by frustration. Notably, despite an even larger amount of error-related negative feedback, the task-induced upset was suppressed in the group receiving anodal tDCS. Moreover, inhibition of task-related negative affect was correlated with performance gains, suggesting a close link between enhanced processing speed and consolidation of CC by tDCS. Together, these data provide first evidence that activity enhancing anodal tDCS to the left dlPFC can support focused cognitive processing particularly when challenged by frustration-induced negative affect.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

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N. V. Dhandapani

2015-01-01

Full Text Available This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process.

Science.gov (United States)

Dhandapani, N V; Thangarasu, V S; Sureshkannan, G

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

Working Memory in Children With Neurocognitive Effects From Sickle Cell Disease: Contributions of the Central Executive and Processing Speed

OpenAIRE

Smith, Kelsey E.; Schatz, Jeffrey

2016-01-01

Children with sickle cell disease (SCD) are at risk for working memory deficits due to multiple disease processes. We assessed working memory abilities and related functions in 32 school-age children with SCD and 85 matched comparison children using Baddeley’s working memory model as a framework. Children with SCD performed worse than controls for working memory, central executive function, and processing/rehearsal speed. Central executive function was found to mediate the relationship betwee...

Double Helical Gear Performance Results in High Speed Gear Trains

Science.gov (United States)

Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

2010-01-01

The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

Ring rotational speed trend analysis by FEM approach in a Ring Rolling process

Science.gov (United States)

Allegri, G.; Giorleo, L.; Ceretti, E.

2018-05-01

Ring Rolling is an advanced local incremental forming technology to fabricate directly precise seamless ring-shape parts with various dimensions and materials. In this process two different deformations occur in order to reduce the width and the height of a preform hollow ring; as results a diameter expansion is obtained. In order to guarantee a uniform deformation, the preform is forced toward the Driver Roll whose aim is to transmit the rotation to the ring. The ring rotational speed selection is fundamental because the higher is the speed the higher will be the axial symmetry of the deformation process. However, it is important to underline that the rotational speed will affect not only the final ring geometry but also the loads and energy needed to produce it. Despite this importance in industrial environment, usually, a constant value for the Driver Roll angular velocity is set so to result in a decreasing trend law for the ring rotational speed. The main risk due to this approach is not fulfilling the axial symmetric constrain (due to the diameter expansion) and to generate a high localized ring section deformation. In order to improve the knowledge about this topic in the present paper three different ring rotational speed trends (constant, linearly increasing and linearly decreasing) were investigated by FEM approach. Results were compared in terms of geometrical and dimensional analysis, loads and energies required.

In-process tool rotational speed variation with constant heat input in friction stir welding of AZ31 sheets with variable thickness

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Buffa, Gianluca; Campanella, Davide; Forcellese, Archimede; Fratini, Livan; Simoncini, Michela

2017-10-01

In the present work, friction stir welding experiments on AZ31 magnesium alloy sheets, characterized by a variable thickness along the welding line, were carried out. The approach adapted during welding consisted in maintaining constant the heat input to the joint. To this purpose, the rotational speed of the pin tool was increased with decreasing thickness and decreased with increasing thickness in order to obtain the same temperatures during welding. The amount by which the rotational speed was changed as a function of the sheet thickness was defined on the basis of the results given by FEM simulations of the FSW process. Finally, the effect of the in-process variation of the tool rotational speed on the mechanical and microstructural properties of FSWed joints was analysed by comparing both the nominal stress vs. nominal strain curves and microstructure of FSWed joints obtained in different process conditions. It was observed that FSW performed by keeping constant the heat input to the joint leads to almost coincident results both in terms of the curve shape, ultimate tensile strength and ultimate elongation values, and microstructure.

High-Speed, High-Performance DQPSK Optical Links with Reduced Complexity VDFE Equalizers

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Maki Nanou

2017-02-01

Full Text Available Optical transmission technologies optimized for optical network segments sensitive to power consumption and cost, comprise modulation formats with direct detection technologies. Specifically, non-return to zero differential quaternary phase shift keying (NRZ-DQPSK in deployed fiber plants, combined with high-performance, low-complexity electronic equalizers to compensate residual impairments at the receiver end, can be proved as a viable solution for high-performance, high-capacity optical links. Joint processing of the constructive and the destructive signals at the single-ended DQPSK receiver provides improved performance compared to the balanced configuration, however, at the expense of higher hardware requirements, a fact that may not be neglected especially in the case of high-speed optical links. To overcome this bottleneck, the use of partially joint constructive/destructive DQPSK equalization is investigated in this paper. Symbol-by-symbol equalization is performed by means of Volterra decision feedback-type equalizers, driven by a reduced subset of signals selected from the constructive and the destructive ports of the optical detectors. The proposed approach offers a low-complexity alternative for electronic equalization, without sacrificing much of the performance compared to the fully-deployed counterpart. The efficiency of the proposed equalizers is demonstrated by means of computer simulation in a typical optical transmission scenario.

The Effect of Two Speed Endurance Training Regimes on Performance of Soccer Players

Science.gov (United States)

Iaia, F. Marcello; Fiorenza, Matteo; Perri, Enrico; Alberti, Giampietro; Millet, Grégoire P.; Bangsbo, Jens

2015-01-01

In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players (age 18.5±1 yr, height 179.5±6.5 cm, body mass 74.3±6.5 kg) reduced the training volume by ~20% and replaced their habitual fitness conditioning work with either speed endurance production (SEP; n = 6) or speed endurance maintenance (SEM; n = 7) training, three times per wk. SEP training consisted of 6–8 reps of 20-s all-out running bouts followed by 2 min of passive recovery, whereas SEM training was characterized by 6–8 x 20-s all-out efforts interspersed with 40 s of passive recovery. SEP training reduced (pstrategies target different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles’ ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in trained young soccer players. PMID:26394225

High-speed resistance training is more effective than low-speed resistance training to increase functional capacity and muscle performance in older women.

Science.gov (United States)

Ramírez-Campillo, Rodrigo; Castillo, Angélica; de la Fuente, Carlos I; Campos-Jara, Christian; Andrade, David C; Álvarez, Cristian; Martínez, Cristian; Castro-Sepúlveda, Mauricio; Pereira, Ana; Marques, Mário C; Izquierdo, Mikel

2014-10-01

To examine the effects of 12 weeks of high-speed resistance training (RT) versus low-speed RT on muscle strength [one repetition of maximum leg-press (1RMLP) and bench-press (1RMBP), plus dominant (HGd) and non-dominant maximum isometric handgrip], power [counter-movement jump (CMJ), ball throwing (BT) and 10-m walking sprint (S10)], functional performance [8-foot up-and-go test (UG) and sit-to-stand test (STS)], and perceived quality of life in older women. 45 older women were divided into a high-speed RT group [EG, n=15, age=66.3±3.7y], a low-speed RT group [SG, n=15, age=68.7±6.4y] and a control group [CG, n=15, age=66.7±4.9y]. The SG and EG were submitted to a similar 12-week RT program [3 sets of 8 reps at 40-75% of the one-repetition maximum (1work per exercise without CMJ and BT). Over the 12-week training period, both RT groups showed small to large clinically significant improvements in the dependent variables; however, a significant difference was found between the EG and SG for the performance changes in BT, S10 and UG (20% vs. 11%, pperformance and quality of life in older women, although a high-speed RT program induces greater improvements in muscle power and functional capacity. Copyright © 2014 Elsevier Inc. All rights reserved.

Level of recall, retrieval speed, and variability on the Cued-Recall Retrieval Speed Task (CRRST) in individuals with amnestic mild cognitive impairment.

Science.gov (United States)

Ramratan, Wendy S; Rabin, Laura A; Wang, Cuiling; Zimmerman, Molly E; Katz, Mindy J; Lipton, Richard B; Buschke, Herman

2012-03-01

Individuals with amnestic mild cognitive impairment (aMCI) show deficits on traditional episodic memory tasks and reductions in speed of performance on reaction time tasks. We present results on a novel task, the Cued-Recall Retrieval Speed Task (CRRST), designed to simultaneously measure level and speed of retrieval. A total of 390 older adults (mean age, 80.2 years), learned 16 words based on corresponding categorical cues. In the retrieval phase, we measured accuracy (% correct) and retrieval speed/reaction time (RT; time from cue presentation to voice onset of a correct response) across 6 trials. Compared to healthy elderly adults (HEA, n = 303), those with aMCI (n = 87) exhibited poorer performance in retrieval speed (difference = -0.13; p cued-learning and processing speed variability may facilitate early detection of dementia in at-risk older adults.

Cognitive processing speed in older adults: relationship with white matter integrity.

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Geoffrey A Kerchner

Full Text Available Cognitive processing slows with age. We sought to determine the importance of white matter integrity, assessed by diffusion tensor imaging (DTI, at influencing cognitive processing speed among normal older adults, assessed using a novel battery of computerized, non-verbal, choice reaction time tasks. We studied 131 cognitively normal adults aged 55-87 using a cross-sectional design. Each participant underwent our test battery, as well as MRI with DTI. We carried out cross-subject comparisons using tract-based spatial statistics. As expected, reaction time slowed significantly with age. In diffuse areas of frontal and parietal white matter, especially the anterior corpus callosum, fractional anisotropy values correlated negatively with reaction time. The genu and body of the corpus callosum, superior longitudinal fasciculus, and inferior fronto-occipital fasciculus were among the areas most involved. This relationship was not explained by gray or white matter atrophy or by white matter lesion volume. In a statistical mediation analysis, loss of white matter integrity mediated the relationship between age and cognitive processing speed.

Sex differences in the relationship between prolactin levels and impaired processing speed in early psychosis.

Science.gov (United States)

Montalvo, Itziar; Nadal, Roser; Armario, Antonio; Gutiérrez-Zotes, Alfonso; Creus, Marta; Cabezas, Ángel; Solé, Montse; Algora, Maria José; Sánchez-Gistau, Vanessa; Vilella, Elisabet; Labad, Javier

2018-06-01

Hyperprolactinaemia is commonly observed in people with psychotic disorders due to D2 receptor blockade by antipsychotic drugs, although it may also exist in drug-naïve patients with first-episode psychosis. Recent studies suggest that hyperprolactinaemia may have a negative impact on cognitive function in people with early psychosis. We aimed to explore whether there are sex differences in the association between prolactin levels and cognitive performance in early psychosis patients. We studied 60 young patients with early psychosis (aged 18-35 years, 35% females) and a sex- and age-matched control group of 50 healthy subjects. Cognitive assessment was performed with the MATRICS Consensus Cognitive Battery. Prolactin, total cortisol, follicular-stimulating hormone, luteal hormone and sex steroids (testosterone in men, oestradiol and progesterone in women) were measured in plasma. Salivary cortisol was measured at different sampling times (awakening response, 10:00 and 23:00). Psychopathological status was assessed, and antipsychotic treatment was registered. Multiple linear regression analyses were used to explore the relationship between prolactin and cognitive tasks while adjusting for covariates. Prolactin levels were associated with impaired processing speed in men, and this association was independent of cortisol and testosterone. In women, prolactin levels were not associated with processing speed tasks, although we observed a negative effect of prolactin on verbal learning and spatial working memory in female healthy subjects. The male-dependent effect maintained its significance after adjusting for education status, antipsychotic treatment and negative symptoms. Our study demonstrates that the previously reported association between high prolactin levels and impaired cognitive processes in early psychosis is restricted to men.

Pedestrian headform testing: inferring performance at impact speeds and for headform masses not tested, and estimating average performance in a range of real-world conditions.

Science.gov (United States)

Hutchinson, T Paul; Anderson, Robert W G; Searson, Daniel J

2012-01-01

Tests are routinely conducted where instrumented headforms are projected at the fronts of cars to assess pedestrian safety. Better information would be obtained by accounting for performance over the range of expected impact conditions in the field. Moreover, methods will be required to integrate the assessment of secondary safety performance with primary safety systems that reduce the speeds of impacts. Thus, we discuss how to estimate performance over a range of impact conditions from performance in one test and how this information can be combined with information on the probability of different impact speeds to provide a balanced assessment of pedestrian safety. Theoretical consideration is given to 2 distinct aspects to impact safety performance: the test impact severity (measured by the head injury criterion, HIC) at a speed at which a structure does not bottom out and the speed at which bottoming out occurs. Further considerations are given to an injury risk function, the distribution of impact speeds likely in the field, and the effect of primary safety systems on impact speeds. These are used to calculate curves that estimate injuriousness for combinations of test HIC, bottoming out speed, and alternative distributions of impact speeds. The injuriousness of a structure that may be struck by the head of a pedestrian depends not only on the result of the impact test but also the bottoming out speed and the distribution of impact speeds. Example calculations indicate that the relationship between the test HIC and injuriousness extends over a larger range than is presently used by the European New Car Assessment Programme (Euro NCAP), that bottoming out at speeds only slightly higher than the test speed can significantly increase the injuriousness of an impact location and that effective primary safety systems that reduce impact speeds significantly modify the relationship between the test HIC and injuriousness. Present testing regimes do not take fully into

Effect of assistance exercises for the snatch on barbell speed and performance for weightlifters

Directory of Open Access Journals (Sweden)

Khaled Ebada

2016-07-01

Full Text Available This study aims to identify Effect of assistance exercises for the snatch on barbell speed and performance for Weightlifters. Applied study on a sample of 14 lifters from the Youth weightlifters team in Beni Suef cities/Egypt of the season 2014/2015, the researcher used experimental method to design two groups; one experimental consisted of 7 lifters and the other control group of 7 lifters. Where the average age of 18.21 ± 0.80 years, height 174.28 ± 6.03 cm, weight 74.14 ± 8.88 kg and age training 3.92 ± 0.91 month. The experimental group underwent an assistance exercises for the snatch program for barbell speed and performance in the snatch, while the control group underwent a training program with exercises classic. Assistance exercises for the snatch program Continued for 8 Weeks 5 times per week and the training session lasted 2 hours. The training program using exercise showed a statistically significant improvement for assistance exercises on barbell speed, velocity (vertical, horizontal for snatch lift and performance weightlifters. Interest in using assistance exercises for snatch and private exercises of pull, power snatch and squat snatch has an important role in the success of the performance of the snatch. Training according to power curve, speed and time of the barbell trajectory and muscle working performance. The need for evaluation of barbell trajectory during the performance by modern techniques for analysis of kinetic activity links it with training programs for weightlifters. These results must be taken into account by the coaches and weightlifters to use the assistance exercises for snatch to improve the kinetic performance and the level of achievement lifting snatch for weightlifters.

Working memory - not processing speed - mediates fluid intelligence deficits associated with attention deficit/hyperactivity disorder symptoms.

Science.gov (United States)

Brydges, Christopher R; Ozolnieks, Krista L; Roberts, Gareth

2017-09-01

Attention deficit/hyperactivity disorder (ADHD) is a psychological condition characterized by inattention and hyperactivity. Cognitive deficits are commonly observed in ADHD patients, including impaired working memory, processing speed, and fluid intelligence, the three of which are theorized to be closely associated with one another. In this study, we aimed to determine if decreased fluid intelligence was associated with ADHD, and was mediated by deficits in working memory and processing speed. This study tested 142 young adults from the general population on a range of working memory, processing speed, and fluid intelligence tasks, and an ADHD self-report symptoms questionnaire. Results showed that total and hyperactive ADHD symptoms correlated significantly and negatively with fluid intelligence, but this association was fully mediated by working memory. However, inattentive symptoms were not associated with fluid intelligence. Additionally, processing speed was not associated with ADHD symptoms at all, and was not uniquely predictive of fluid intelligence. The results provide implications for working memory training programs for ADHD patients, and highlight potential differences between the neuropsychological profiles of ADHD subtypes. © 2015 The British Psychological Society.

Cognitive processing speed is related to fall frequency in older adults with multiple sclerosis.

Science.gov (United States)

Sosnoff, Jacob J; Balantrapu, Swathi; Pilutti, Lara A; Sandroff, Brian M; Morrison, Steven; Motl, Robert W

2013-08-01

To examine mobility, balance, fall risk, and cognition in older adults with multiple sclerosis (MS) as a function of fall frequency. Retrospective, cross-sectional design. University research laboratory. Community-dwelling persons with MS (N=27) aged between 50 and 75 years were divided into 2 groups-single-time (n=11) and recurrent (n=16; >2 falls/12 mo) fallers-on the basis of fall history. Not applicable. Mobility was assessed using a variety of measures including Multiple Sclerosis Walking Scale-12, walking speed (Timed 25-Foot Walk test), endurance (6-Minute Walk test), and functional mobility (Timed Up and Go test). Balance was assessed with the Berg Balance Scale, posturography, and self-reported balance confidence. Fall risk was assessed with the Physiological Profile Assessment. Cognitive processing speed was quantified with the Symbol Digit Modalities Test and the Paced Auditory Serial Addition Test. Recurrent fallers had slower cognitive processing speed than single-time fallers (P ≤.01). There was no difference in mobility, balance, or fall risk between recurrent and single-time fallers (P>.05). Results indicated that cognitive processing speed is associated with fall frequency and may have implications for fall prevention strategies targeting recurrent fallers with MS. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effects of tool speeds and corresponding torque/energy on stir zone formation during friction stir welding/processing

International Nuclear Information System (INIS)

Cui, S; Chen, Z W

2009-01-01

The way processing parameters and the measurable thermomechanical responses relate to the individual and combined flows forming the different processed zones during friction stir welding/processing has been studied. Experimentally, a cast Al-7Si-0.3Mg alloy was used to provide readily identifiable processed zones. A series of friction stir experiments covering a wide range of tool forward and rotation speeds were conducted followed by the measurement of individual and combined stir areas. It has been found that the basic modes of material flow did not change but the relative volume of each flow depended on both forward and rotation speeds. The trends observed in the present data explain how pin rotation relates to the material transportation mechanism and the associated torque required. This data also explains how forward speed, not rotation speed, relates to specific energy and the volume of the total stir zone.

Design of high-speed planing hulls for the improvement of resistance and seakeeping performance

Directory of Open Access Journals (Sweden)

Dong Jin Kim

2013-03-01

Full Text Available High-speed vessels require good resistance and seakeeping performance for safe operations in rough seas. The resistance and seakeeping performance of high-speed vessels varies significantly depending on their hull forms. In this study, three planing hulls that have almost the same displacement and principal dimension are designed and the hydrodynamic characteristics of those hulls are estimated by high-speed model tests. All model ships are deep-V type planing hulls. The bows of no.2 and no.3 model ships are designed to be advantageous for wave-piercing in rough water. No. 2 and no. 3 model ships have concave and straight forebody cross-sections, respectively. And length-to-beam ratios of no.2 and no.3 models are larger than that of no.1 model. In calm water tests, running attitude and resistance of model ships are measured at various speeds. And motion tests in regular waves are performed to measure the heave and pitch motion responses of the model ships. The required power of no.1 (VPS model is smallest, but its vertical motion amplitudes in waves are the largest. No.2 (VWC model shows the smallest motion amplitudes in waves, but needs the greatest power at high speed. The resistance and seakeeping performance of no.3 (VWS model ship are the middle of three model ships, respectively. And in regular waves, no.1 model ship experiences ‘fly over’ phenomena around its resonant frequency. Vertical accelerations at specific locations such as F.P., center of gravity of model ships are measured at their resonant frequency. It is necessary to measure accelerations by accelerometers or other devices in model tests for the accurate prediction of vertical accelerations in real ships.

Breaking the speed limit--comparative sprinting performance of brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta)

Science.gov (United States)

Castro-Santos, Theodore; Sanz-Ronda, Francisco Javier; Ruiz-Legazpi, Jorge

2013-01-01

Sprinting behavior of free-ranging fish has long been thought to exceed that of captive fish. Here we present data from wild-caught brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta), volitionally entering and sprinting against high-velocity flows in an open-channel flume. Performance of the two species was nearly identical, with the species attaining absolute speeds > 25 body lengths·s−1. These speeds far exceed previously published observations for any salmonid species and contribute to the mounting evidence that commonly accepted estimates of swimming performance are low. Brook trout demonstrated two distinct modes in the relationship between swim speed and fatigue time, similar to the shift from prolonged to sprint mode described by other authors, but in this case occurring at speeds > 19 body lengths·s−1. This is the first demonstration of multiple modes of sprint swimming at such high swim speeds. Neither species optimized for distance maximization, however, indicating that physiological limits alone are poor predictors of swimming performance. By combining distributions of volitional swim speeds with endurance, we were able to account for >80% of the variation in distance traversed by both species.

Speed in Acquisitions

DEFF Research Database (Denmark)

Meglio, Olimpia; King, David R.; Risberg, Annette

2017-01-01

The advantage of speed is often invoked by academics and practitioners as an essential condition during post-acquisition integration, frequently without consideration of the impact earlier decisions have on acquisition speed. In this article, we examine the role speed plays in acquisitions across...... the acquisition process using research organized around characteristics that display complexity with respect to acquisition speed. We incorporate existing research with a process perspective of acquisitions in order to present trade-offs, and consider the influence of both stakeholders and the pre......-deal-completion context on acquisition speed, as well as the organization’s capabilities to facilitating that speed. Observed trade-offs suggest both that acquisition speed often requires longer planning time before an acquisition and that associated decisions require managerial judgement. A framework for improving...

Effects of impeller diameter and rotational speed on performance of pump running in turbine mode

International Nuclear Information System (INIS)

Jain, Sanjay V.; Swarnkar, Abhishek; Motwani, Karan H.; Patel, Rajesh N.

2015-01-01

Highlights: • Experiments done between 900 and 1500 rpm with original, 10% and 20% trimmed impellers. • The performance of PAT was found better in speed range of 1000–1200 rpm. • Blade rounding led to 3–4% rise in efficiency at rated speed with existing impeller. • Correlation developed has predicted η BEP within ±10% of experimental results. - Abstract: The major limitations of mini/micro hydropower schemes is the higher cost of small capacity hydro turbines. Also, it is very cumbersome, time consuming and expensive to develop the site specific turbines corresponding to local site conditions in mini/micro hydro range. In such plants, small centrifugal pumps can be used in turbine mode by running in the reverse direction. The efficiency of pump as turbines (PATs) is usually lower than the conventional hydro turbines; however, there may be substantial decrease in the capital cost of the plant. Hydropower plants usually runs at part load for several months in a year due to insufficient water availability for the power generation. The application range of PAT can be widened if its part load and/or maximum efficiency can be improved. In the present study, experimental investigations are carried out on centrifugal pump running in turbine mode to optimize its geometric and operational parameters e.g. impeller diameter and rotational speed. The experiments were performed in the wide range of rotational speeds varying from 900 to 1500 rpm with original (∅ 250 mm), 10% trimmed (∅ 225 mm) and 20% trimmed (∅ 200 mm) impellers. Impeller trimming led to improvement in efficiency at part load operating conditions. The performance of PAT was found better at the lower speeds than that at the rated speed. The effects of blade rounding were studied in all the cases and it led to 3–4% rise in efficiency at rated speed with the original impeller. The empirical correlation is also developed for prediction of efficiency in terms of impeller diameter and rotational

An Innovative Hybrid Model Based on Data Pre-Processing and Modified Optimization Algorithm and Its Application in Wind Speed Forecasting

Directory of Open Access Journals (Sweden)

Ping Jiang

2017-07-01

Full Text Available Wind speed forecasting has an unsuperseded function in the high-efficiency operation of wind farms, and is significant in wind-related engineering studies. Back-propagation (BP algorithms have been comprehensively employed to forecast time series that are nonlinear, irregular, and unstable. However, the single model usually overlooks the importance of data pre-processing and parameter optimization of the model, which results in weak forecasting performance. In this paper, a more precise and robust model that combines data pre-processing, BP neural network, and a modified artificial intelligence optimization algorithm was proposed, which succeeded in avoiding the limitations of the individual algorithm. The novel model not only improves the forecasting accuracy but also retains the advantages of the firefly algorithm (FA and overcomes the disadvantage of the FA while optimizing in the later stage. To verify the forecasting performance of the presented hybrid model, 10-min wind speed data from Penglai city, Shandong province, China, were analyzed in this study. The simulations revealed that the proposed hybrid model significantly outperforms other single metaheuristics.

Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) processing speed scores as measures of noncredible responding: The third generation of embedded performance validity indicators.

Science.gov (United States)

Erdodi, Laszlo A; Abeare, Christopher A; Lichtenstein, Jonathan D; Tyson, Bradley T; Kucharski, Brittany; Zuccato, Brandon G; Roth, Robert M

2017-02-01

Research suggests that select processing speed measures can also serve as embedded validity indicators (EVIs). The present study examined the diagnostic utility of Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) subtests as EVIs in a mixed clinical sample of 205 patients medically referred for neuropsychological assessment (53.3% female, mean age = 45.1). Classification accuracy was calculated against 3 composite measures of performance validity as criterion variables. A PSI ≤79 produced a good combination of sensitivity (.23-.56) and specificity (.92-.98). A Coding scaled score ≤5 resulted in good specificity (.94-1.00), but low and variable sensitivity (.04-.28). A Symbol Search scaled score ≤6 achieved a good balance between sensitivity (.38-.64) and specificity (.88-.93). A Coding-Symbol Search scaled score difference ≥5 produced adequate specificity (.89-.91) but consistently low sensitivity (.08-.12). A 2-tailed cutoff on the Coding/Symbol Search raw score ratio (≤1.41 or ≥3.57) produced acceptable specificity (.87-.93), but low sensitivity (.15-.24). Failing ≥2 of these EVIs produced variable specificity (.81-.93) and sensitivity (.31-.59). Failing ≥3 of these EVIs stabilized specificity (.89-.94) at a small cost to sensitivity (.23-.53). Results suggest that processing speed based EVIs have the potential to provide a cost-effective and expedient method for evaluating the validity of cognitive data. Given their generally low and variable sensitivity, however, they should not be used in isolation to determine the credibility of a given response set. They also produced unacceptably high rates of false positive errors in patients with moderate-to-severe head injury. Combining evidence from multiple EVIs has the potential to improve overall classification accuracy. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Click trains and the rate of information processing: does "speeding up" subjective time make other psychological processes run faster?

Science.gov (United States)

Jones, Luke A; Allely, Clare S; Wearden, John H

2011-02-01

A series of experiments demonstrated that a 5-s train of clicks that have been shown in previous studies to increase the subjective duration of tones they precede (in a manner consistent with "speeding up" timing processes) could also have an effect on information-processing rate. Experiments used studies of simple and choice reaction time (Experiment 1), or mental arithmetic (Experiment 2). In general, preceding trials by clicks made response times significantly shorter than those for trials without clicks, but white noise had no effects on response times. Experiments 3 and 4 investigated the effects of clicks on performance on memory tasks, using variants of two classic experiments of cognitive psychology: Sperling's (1960) iconic memory task and Loftus, Johnson, and Shimamura's (1985) iconic masking task. In both experiments participants were able to recall or recognize significantly more information from stimuli preceded by clicks than those preceded by silence.

Tse computers. [ultrahigh speed optical processing for two dimensional binary image

Science.gov (United States)

Schaefer, D. H.; Strong, J. P., III

1977-01-01

An ultra-high-speed computer that utilizes binary images as its basic computational entity is being developed. The basic logic components perform thousands of operations simultaneously. Technologies of the fiber optics, display, thin film, and semiconductor industries are being utilized in the building of the hardware.

The effect of aging in recollective experience: the processing speed and executive functioning hypothesis.

Science.gov (United States)

Bugaiska, Aurélia; Clarys, David; Jarry, Caroline; Taconnat, Laurence; Tapia, Géraldine; Vanneste, Sandrine; Isingrini, Michel

2007-12-01

This study was designed to investigate the effects of aging on consciousness in recognition memory, using the Remember/Know/Guess procedure (Gardiner, J. M., & Richarson-Klavehn, A. (2000). Remembering and Knowing. In E. Tulving & F. I. M. Craik (Eds.), The Oxford Handbook of Memory. Oxford University Press.). In recognition memory, older participants report fewer occasions on which recognition is accompanied by recollection of the original encoding context. Two main hypotheses were tested: the speed mediation hypothesis (Salthouse, T. A. (1996). The processing-speed theory of adult age differences in cognition. Psychological Review, 3, 403-428) and the executive-aging hypothesis (West, R. L. (1996). An application of prefrontal cortex function theory to cognitive aging. Psychological Bulletin, 120, 272-292). A group of young and a group of older adults took a recognition test in which they classified their responses according to Gardiner, J. M., & Richarson-Klavehn, A. (2000). Remembering and Knowing. In E. Tulving & F. I. M. Craik (Eds.), The Oxford Handbook of Memory. Oxford University Press. remember-know-guess paradigm. Subsequently, participants completed processing speed and executive function tests. The results showed that among the older participants, R responses decreased, but K responses did not. Moreover, a hierarchical regression analysis supported the view that the effect of age in recollection experience is determined by frontal lobe integrity and not by diminution of processing speed.

Evaluation and analysis on the coupling performance of a high-speed turboexpander compressor

Science.gov (United States)

Chen, Shuangtao; Fan, Yufeng; Yang, Shanju; Chen, Xingya; Hou, Yu

2017-12-01

A high-speed turboexpander compressor (TEC) for small reverse Brayton air refrigerator is tested and analyzed in the present work. A TEC consists of an expander and a compressor, which are coupled together and interact with each other directly. Meanwhile, the expander and compressor have different effects on the refrigerator. The TEC overall efficiency, which contains effects of the expander's expansion, the compressor's pre-compression, and the pressure drop between them, was proved. It unifies influences of both compression and expansion processes on the COP of refrigerator and could be used to evaluate the TEC overall performance. Then, the coupling parameters were analyzed, which shows that for a TEC, the expander efficiency should be fully utilized first, followed by the compressor pressure ratio. Experiments were carried out to test the TEC coupling performances. The results indicated that, the TEC overall efficiency could reach 67.2%, and meanwhile 22.3% of the energy output was recycled.

Anxiety state affects information processing speed in patients with multiple sclerosis.

Science.gov (United States)

Goretti, Benedetta; Viterbo, R G; Portaccio, E; Niccolai, C; Hakiki, B; Piscolla, E; Iaffaldano, P; Trojano, M; Amato, M P

2014-04-01

The aim of this study was to investigate the impact of anxiety on the cognitive performance of a clinical sample of relapsing-remitting (RR) MS patients. One hundred ninety patients (140 females) were included in the study and assessed through the beck depression inventory, the state-trait anxiety inventory and the Rao's brief repeatable battery which assesses cognitive domains most frequently impaired in MS. As for neuropsychological performance, a total of 76 (40%) subjects fulfilled our criterion for cognitive impairment. Tests most frequently failed by cognitive impairment (CI) patients were those assessing complex attention and information processing speed [Simbol Digit Modalities Test (SDMT), Paced Auditory Serial Auditory Test (PASAT) 3 and 2] and verbal memory. In the univariate analysis, state anxiety was related to failure on the SDMT (p = 0.042), and marginally, to failure on the PASAT-3 (p = 0.068), and to the presence of CI (p = 0.082). Moderate/severe depression was detected in 38 (20%) patients and fatigue in 109 (57%). Higher depression scores were related to impairment on the ST (OR = 1.05; 95% CI 1.01-1.10; p = 0.029).

Anthropometric, biomechanical, and isokinetic strength predictors of ball release speed in high-performance cricket fast bowlers.

Science.gov (United States)

Wormgoor, Shohn; Harden, Lois; Mckinon, Warrick

2010-07-01

Fast bowling is fundamental to all forms of cricket. The purpose of this study was to identify parameters that contribute to high ball release speeds in cricket fast bowlers. We assessed anthropometric dimensions, concentric and eccentric isokinetic strength of selected knee and shoulder muscle groups, and specific aspects of technique from a single delivery in 28 high-performance fast bowlers (age 22.0 +/- 3.0 years, ball release speed 34.0 +/- 1.3 m s(-1)). Six 50-Hz cameras and the Ariel Performance Analysis System software were used to analyse the fast and accurate deliveries. Using Pearson's correlation, parameters that showed significant associations with ball release speed were identified. The findings suggest that greater front leg knee extension at ball release (r=0.52), shoulder alignment in the transverse plane rotated further away from the batsman at front foot strike (r=0.47), greater ankle height during the delivery stride (r=0.44), and greater shoulder extension strength (r=0.39) contribute significantly to higher ball release speeds. Predictor variables failed to allow their incorporation into a multivariate model, which is known to exist in less accomplished bowlers, suggesting that factors that determine ball release speed found in other groups may not apply to high-performance fast bowlers.

Optical signal processing techniques and applications of optical phase modulation in high-speed communication systems

Science.gov (United States)

Deng, Ning

In recent years, optical phase modulation has attracted much research attention in the field of fiber optic communications. Compared with the traditional optical intensity-modulated signal, one of the main merits of the optical phase-modulated signal is the better transmission performance. For optical phase modulation, in spite of the comprehensive study of its transmission performance, only a little research has been carried out in terms of its functions, applications and signal processing for future optical networks. These issues are systematically investigated in this thesis. The research findings suggest that optical phase modulation and its signal processing can greatly facilitate flexible network functions and high bandwidth which can be enjoyed by end users. In the thesis, the most important physical-layer technology, signal processing and multiplexing, are investigated with optical phase-modulated signals. Novel and advantageous signal processing and multiplexing approaches are proposed and studied. Experimental investigations are also reported and discussed in the thesis. Optical time-division multiplexing and demultiplexing. With the ever-increasing demand on communication bandwidth, optical time division multiplexing (OTDM) is an effective approach to upgrade the capacity of each wavelength channel in current optical systems. OTDM multiplexing can be simply realized, however, the demultiplexing requires relatively complicated signal processing and stringent timing control, and thus hinders its practicability. To tackle this problem, in this thesis a new OTDM scheme with hybrid DPSK and OOK signals is proposed. Experimental investigation shows this scheme can greatly enhance the demultiplexing timing misalignment and improve the demultiplexing performance, and thus make OTDM more practical and cost effective. All-optical signal processing. In current and future optical communication systems and networks, the data rate per wavelength has been approaching

Automatic in-process chatter avoidance in the high-speed milling process

NARCIS (Netherlands)

Dijk, van N.J.M.; Doppenberg, E.J.J.; Faassen, R.P.H.; Wouw, van de N.; Oosterling, J.A.J.; Nijmeijer, H.

2010-01-01

High-speed milling is often used in industry to maximize productivity of the manufacturing of high-technology components, such as aeronautical components, mold, and dies. The occurrence of chatter highly limits the efficiency and accuracy of high-speed milling operations. In this paper, two control

High-Performance Pseudo-Random Number Generation on Graphics Processing Units

OpenAIRE

Nandapalan, Nimalan; Brent, Richard P.; Murray, Lawrence M.; Rendell, Alistair

2011-01-01

This work considers the deployment of pseudo-random number generators (PRNGs) on graphics processing units (GPUs), developing an approach based on the xorgens generator to rapidly produce pseudo-random numbers of high statistical quality. The chosen algorithm has configurable state size and period, making it ideal for tuning to the GPU architecture. We present a comparison of both speed and statistical quality with other common parallel, GPU-based PRNGs, demonstrating favourable performance o...

Race Factors Affecting Performance Times in Elite Long-Track Speed Skating.

Science.gov (United States)

Noordhof, Dionne A; Mulder, Roy C; de Koning, Jos J; Hopkins, Will G

2016-05-01

Analysis of sport performance can provide effects of environmental and other venue-specific factors in addition to estimates of within-athlete variability between competitions, which determines smallest worthwhile effects. To analyze elite long-track speed-skating events. Log-transformed performance times were analyzed with a mixed linear model that estimated percentage mean effects for altitude, barometric pressure, type of rink, and competition importance. In addition, coefficients of variation representing residual venue-related differences and within-athlete variability between races within clusters spanning ~8 d were determined. Effects and variability were assessed with magnitude-based inference. A 1000-m increase in altitude resulted in very large mean performance improvements of 2.8% in juniors and 2.1% in seniors. An increase in barometric pressure of 100 hPa resulted in a moderate reduction in performance of 1.1% for juniors but an unclear effect for seniors. Only juniors competed at open rinks, resulting in a very large reduction in performance of 3.4%. Juniors and seniors showed small performance improvements (0.4% and 0.3%) at the more important competitions. After accounting for these effects, residual venue-related variability was still moderate to large. The within-athlete within-cluster race-to-race variability was 0.3-1.3%, with a small difference in variability between male (0.8%) and female juniors (1.0%) and no difference between male and female seniors (both 0.6%). The variability in performance times of skaters is similar to that of athletes in other sports in which air or water resistance limits speed. A performance enhancement of 0.1-0.4% by top-10 athletes is necessary to increase medal-winning chances by 10%.

STEADY STATE PERFORMANCES ANALYSIS OF MODERN MARINE TWO-STROKE LOW SPEED DIESEL ENGINE USING MLP NEURAL NETWORK MODEL

Directory of Open Access Journals (Sweden)

Ozren Bukovac

2016-01-01

Full Text Available Compared to the other marine engines for ship propulsion, turbocharged two-stroke low speed diesel engines have advantages due to their high efficiency and reliability. Modern low speed ”intelligent” marine diesel engines have a flexibility in its operation due to the variable fuel injection strategy and management of the exhaust valve drive. This paper carried out verified zerodimensional numerical simulations which have been used for MLP (Multilayer Perceptron neural network predictions of marine two-stroke low speed diesel engine steady state performances. The developed MLP neural network was used for marine engine optimized operation control. The paper presents an example of achieving lowest specific fuel consumption and for minimization of the cylinder process highest temperature for reducing NOx emission. Also, the developed neural network was used to achieve optimal exhaust gases heat flow for utilization. The obtained data maps give insight into the optimal working areas of simulated marine diesel engine, depending on the selected start of the fuel injection (SOI and the time of the exhaust valve opening (EVO.

Effect of rotation speed and welding speed on Friction Stir Welding of AA1100 Aluminium alloy

Science.gov (United States)

Raja, P.; Bojanampati, S.; Karthikeyan, R.; Ganithi, R.

2018-04-01

Aluminum AA1100 is the most widely used grade of Aluminium due to its excellent corrosion resistance, high ductility and reflective finish, the selected material was welded with Friction Stir Welding (FSW) process on a CNC machine, using a combination of different tool rotation speed (1500 rpm, 2500 rpm, 3500 rpm) and welding speed (10 mm/min, 30 mm/min, 50 mm/min) as welding parameters. The effect of FSW using this welding parameter was studied by measuring the ultimate tensile strength of the welded joints. A high-speed steel tool was prepared for welding the Aluminium AA1100 alloy having an 8mm shoulder diameter and pin dimension of 4mm diameter and 2.8 mm length. The welded joints were tested using the universal testing machine. It was found that Ultimate Tensile Strength of FSW specimen was highest with a value of 98.08 MPa when the weld was performed at rotation speed of 1500 RPM and welding speed of 50 mm/min.

Acceleration performance of individual European sea bass Dicentrarchus labrax measured with a sprint performance chamber: comparison with high-speed cinematography and correlates with ecological performance.

Science.gov (United States)

Vandamm, Joshua P; Marras, Stefano; Claireaux, Guy; Handelsman, Corey A; Nelson, Jay A

2012-01-01

Locomotor performance can influence the ecological and evolutionary success of a species. For fish, favorable outcomes of predator-prey encounters are often presumably due to robust acceleration ability. Although escape-response or "fast-start" studies utilizing high-speed cinematography are prevalent, little is known about the contribution of relative acceleration performance to ecological or evolutionary success in a species. This dearth of knowledge may be due to the time-consuming nature of analyzing film, which imposes a practical limit on sample sizes. Herein, we present a high-throughput potential alternative for measuring fish acceleration performance using a sprint performance chamber (SPC). The acceleration performance of a large number of juvenile European sea bass (Dicentrarchus labrax) from two populations was analyzed. Animals from both hatchery and natural ontogenies were assessed, and animals of known acceleration ability had their ecological performance measured in a mesocosm environment. Individuals from one population also had their acceleration performance assessed by both high-speed cinematography and an SPC. Acceleration performance measured in an SPC was lower than that measured by classical high-speed video techniques. However, short-term repeatability and interindividual variation of acceleration performance were similar between the two techniques, and the SPC recorded higher sprint swimming velocities. Wild fish were quicker to accelerate in an SPC and had significantly greater accelerations than all groups of hatchery-raised fish. Acceleration performance had no significant effect on ecological performance (as assessed through animal growth and survival in the mesocosms). However, it is worth noting that wild animals did survive predation in the mesocosm better than farmed ones. Moreover, the hatchery-originated fish that survived the mesocosm experiment, when no predators were present, displayed significantly increased acceleration

Action video games do not improve the speed of information processing in simple perceptual tasks.

Science.gov (United States)

van Ravenzwaaij, Don; Boekel, Wouter; Forstmann, Birte U; Ratcliff, Roger; Wagenmakers, Eric-Jan

2014-10-01

Previous research suggests that playing action video games improves performance on sensory, perceptual, and attentional tasks. For instance, Green, Pouget, and Bavelier (2010) used the diffusion model to decompose data from a motion detection task and estimate the contribution of several underlying psychological processes. Their analysis indicated that playing action video games leads to faster information processing, reduced response caution, and no difference in motor responding. Because perceptual learning is generally thought to be highly context-specific, this transfer from gaming is surprising and warrants corroborative evidence from a large-scale training study. We conducted 2 experiments in which participants practiced either an action video game or a cognitive game in 5 separate, supervised sessions. Prior to each session and following the last session, participants performed a perceptual discrimination task. In the second experiment, we included a third condition in which no video games were played at all. Behavioral data and diffusion model parameters showed similar practice effects for the action gamers, the cognitive gamers, and the nongamers and suggest that, in contrast to earlier reports, playing action video games does not improve the speed of information processing in simple perceptual tasks.

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

DEFF Research Database (Denmark)

Tranberg-Hansen, Anders Sejer; Madsen, Jan

2009-01-01

This paper presents the application of a compositional simulation based system-level performance estimation framework on a non-trivial industrial case study. The case study is provided by the Danish company Bang & Olufsen ICEpower a/s and focuses on the exploration of a digital mobile audio...... processing platform. A short overview of the compositional performance estimation framework used is given followed by a presentation of how it is used for performance estimation using an iterative refinement process towards the final implementation. Finally, an evaluation in terms of accuracy and speed...

Processing Determinants of Reading Speed.

Science.gov (United States)

Jackson, Mark D.; McClelland, James L.

1979-01-01

Two groups of undergraduates differing in reading ability were tested on a number of reaction-time tasks designed to determine the speed of encoding visual information at several different levels, tests of sensory functions, verbal and quantitative reasoning ability, short-term auditory memory span, and ability to comprehend spoken text.…

Two speed factors of visual recognition independently correlated with fluid intelligence.

Science.gov (United States)

Tachibana, Ryosuke; Namba, Yuri; Noguchi, Yasuki

2014-01-01

Growing evidence indicates a moderate but significant relationship between processing speed in visuo-cognitive tasks and general intelligence. On the other hand, findings from neuroscience proposed that the primate visual system consists of two major pathways, the ventral pathway for objects recognition and the dorsal pathway for spatial processing and attentive analysis. Previous studies seeking for visuo-cognitive factors of human intelligence indicated a significant correlation between fluid intelligence and the inspection time (IT), an index for a speed of object recognition performed in the ventral pathway. We thus presently examined a possibility that neural processing speed in the dorsal pathway also represented a factor of intelligence. Specifically, we used the mental rotation (MR) task, a popular psychometric measure for mental speed of spatial processing in the dorsal pathway. We found that the speed of MR was significantly correlated with intelligence scores, while it had no correlation with one's IT (recognition speed of visual objects). Our results support the new possibility that intelligence could be explained by two types of mental speed, one related to object recognition (IT) and another for manipulation of mental images (MR).

High-speed packet filtering utilizing stream processors

Science.gov (United States)

Hummel, Richard J.; Fulp, Errin W.

2009-04-01

Parallel firewalls offer a scalable architecture for the next generation of high-speed networks. While these parallel systems can be implemented using multiple firewalls, the latest generation of stream processors can provide similar benefits with a significantly reduced latency due to locality. This paper describes how the Cell Broadband Engine (CBE), a popular stream processor, can be used as a high-speed packet filter. Results show the CBE can potentially process packets arriving at a rate of 1 Gbps with a latency less than 82 μ-seconds. Performance depends on how well the packet filtering process is translated to the unique stream processor architecture. For example the method used for transmitting data and control messages among the pseudo-independent processor cores has a significant impact on performance. Experimental results will also show the current limitations of a CBE operating system when used to process packets. Possible solutions to these issues will be discussed.

Markers of Microbial Translocation and Immune Activation Predict Cognitive Processing Speed in Heavy-Drinking Men Living with HIV

Directory of Open Access Journals (Sweden)

Mollie A. Monnig

2017-09-01

Full Text Available HIV infection and alcohol use disorder are associated with deficits in neurocognitive function. Emerging evidence points to pro-inflammatory perturbations of the gut-brain axis as potentially contributing to neurocognitive impairment in the context of HIV and chronic heavy alcohol use. This study examined whether plasma markers of microbial translocation (LPS from the gastrointestinal tract and related immune activation (sCD14, EndoCAb were associated with neurocognition in 21 men living with HIV who were virally suppressed on antiretroviral therapy. All participants met federal criteria for heavy drinking and were enrolled in a randomized controlled trial (RCT of a brief alcohol intervention. This secondary analysis utilized blood samples and cognitive scores (learning, memory, executive function, verbal fluency, and processing speed obtained at baseline and three-month follow-up of the RCT. In generalized estimating equation models, LPS, sCD14, and EndoCAb individually were significant predictors of processing speed. In a model with all biomarkers, higher LPS and sCD14 both remained significant predictors of lower processing speed. These preliminary findings suggest that inflammation stemming from HIV and/or alcohol could have negative effects on the gut-brain axis, manifested as diminished processing speed. Associations of microbial translocation and immune activation with processing speed in heavy-drinking PLWH warrant further investigation in larger-scale studies.

The Charging Process in a High-speed, Single-cylinder, Four-stroke Engine

Science.gov (United States)

Reynolds, Blake; Schecter, Harry; Taylor, E S

1939-01-01

Experimental measurements and theoretical calculations were made on an aircraft-type, single cylinder engine, in order to determine the physical nature of the inlet process, especially at high piston speeds. The engine was run at speeds from 1,500 to 2,600 r.p.m. (mean piston speeds of 1,370 to 2,380 feet per minute). Measurements were made of the cylinder pressure during the inlet stroke and of the power output and volumetric efficiency. Measurements were also made, with the engine not running, to determine the resistance and mass of air in the inlet valve port at various crank angles. Results of analysis indicate that mass has an appreciable effect, but friction plays the major part in restricting flow. The observed fact that the volumetric efficiency is considerably less than 100 percent is attributed to thermal effects. An estimate was made of the magnitude of these effects in the present case, and their general nature is discussed.

Relationship between strength, power, speed, and change of direction performance of female softball players.

Science.gov (United States)

Nimphius, Sophia; McGuigan, Michael R; Newton, Robert U

2010-04-01

The purpose of this study was to investigate (a) the cross-sectional relationship of strength, power, and performance variables in trained female athletes and (b) determine if the relationship between these variables changes over the course of a season. Ten female softball players (age = 18.1 +/- 1.6 years, height = 166.5 +/- 8.9 cm, and weight = 72.4 +/- 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower body strength (one repetition maximum [1RM]), peak force (PF), peak velocity (PV), and peak power (PP) during jump squats unloaded and loaded, unloaded countermovement vertical jump height (VJH) 1 base and 2 base sprint performance and change of direction performance on dominant and nondominant sides. The testing sessions occurred pre, mid, and post a 20-week training period. Relationship between body weight (BW), relative strength (1RM/BW), VJH, relative PP, relative PF, PV, speed, and change of direction variables were assessed by Pearson product-moment correlation coefficient at each testing session. Significant relationships were found across all time points with BW, speed, and change of direction measures (r = 0.70-0.93) and relative strength and measures of speed and change of direction ability (r = -0.73-0.85). There were no significant relationships between VJH and any measure of performance at any time point. In conclusion, BW and relative strength have strong to very strong correlations with speed and change of direction ability, and these correlations remain consistent over the course of the season. However, it seems as if many relationships vary with time, and their relationships should therefore be investigated longitudinally to better determine if these cross-sectional relationships truly reflect a deterministic relationship.

Relationship between strength qualities and short track speed skating performance in young athletes.

Science.gov (United States)

Felser, S; Behrens, M; Fischer, S; Heise, S; Bäumler, M; Salomon, R; Bruhn, S

2016-02-01

This study analyzed the relationships between isometric as well as concentric maximum voluntary contraction (MVC) strength of the leg muscles and the times as well as speeds over different distances in 17 young short track speed skaters. Isometric as well as concentric single-joint MVC strength and multi-joint MVC strength in a stable (without skates) and unstable (with skates) condition were tested. Furthermore, time during maximum skating performances on ice was measured. Results indicate that maximum torques during eversion and dorsal flexion have a significant influence on skating speed. Concentric MVC strength of the knee extensors was higher correlated with times as well as speeds over the different distances than isometric MVC strength. Multi-joint MVC testing revealed that the force loss between measurements without and with skates amounts to 25%, while biceps femoris and soleus showed decreased muscle activity and peroneus longus, tibialis anterior, as well as rectus femoris exhibited increased muscle activity. The results of this study depict evidence that the skating times and speeds are primarily influenced by concentric MVC strength of the leg extensors. To be able to transfer the strength onto ice in an optimal way, it is necessary to stabilize the knee and ankle joints. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A Gaussian mixture copula model based localized Gaussian process regression approach for long-term wind speed prediction

International Nuclear Information System (INIS)

Yu, Jie; Chen, Kuilin; Mori, Junichi; Rashid, Mudassir M.

2013-01-01

Optimizing wind power generation and controlling the operation of wind turbines to efficiently harness the renewable wind energy is a challenging task due to the intermittency and unpredictable nature of wind speed, which has significant influence on wind power production. A new approach for long-term wind speed forecasting is developed in this study by integrating GMCM (Gaussian mixture copula model) and localized GPR (Gaussian process regression). The time series of wind speed is first classified into multiple non-Gaussian components through the Gaussian mixture copula model and then Bayesian inference strategy is employed to incorporate the various non-Gaussian components using the posterior probabilities. Further, the localized Gaussian process regression models corresponding to different non-Gaussian components are built to characterize the stochastic uncertainty and non-stationary seasonality of the wind speed data. The various localized GPR models are integrated through the posterior probabilities as the weightings so that a global predictive model is developed for the prediction of wind speed. The proposed GMCM–GPR approach is demonstrated using wind speed data from various wind farm locations and compared against the GMCM-based ARIMA (auto-regressive integrated moving average) and SVR (support vector regression) methods. In contrast to GMCM–ARIMA and GMCM–SVR methods, the proposed GMCM–GPR model is able to well characterize the multi-seasonality and uncertainty of wind speed series for accurate long-term prediction. - Highlights: • A novel predictive modeling method is proposed for long-term wind speed forecasting. • Gaussian mixture copula model is estimated to characterize the multi-seasonality. • Localized Gaussian process regression models can deal with the random uncertainty. • Multiple GPR models are integrated through Bayesian inference strategy. • The proposed approach shows higher prediction accuracy and reliability

A pro-forma design for car-carriers: Low-speed performance-based standards

CSIR Research Space (South Africa)

Benade R, Berman R

2015-07-01

Full Text Available the constraints of the pro-forma design met the Level 1 requirements of the low-speed PBS. Future work will ensure compliance with the full set of twelve performance standards. It is estimated that the pro-forma approach as compared to doing full assessments would...

Influence of wind speed on free space optical communication performance for Gaussian beam propagation through non Kolmogorov strong turbulence

International Nuclear Information System (INIS)

Deng Peng; Yuan Xiuhua; Zeng Yanan; Zhao Ming; Luo Hanjun

2011-01-01

In free-space optical communication links, atmospheric turbulence causes fluctuations in both the intensity and the phase of the received signal, affecting link performance. Most theoretical treatments have been described by Kolmogorov's power spectral density model through weak turbulence with constant wind speed. However, several experiments showed that Kolmogorov theory is sometimes incomplete to describe atmospheric turbulence properly, especially through the strong turbulence with variable wind speed, which is known to contribute significantly to the turbulence in the atmosphere. We present an optical turbulence model that incorporates into variable wind speed instead of constant value, a non-Kolmogorov power spectrum that uses a generalized exponent instead of constant standard exponent value 11/3, and a generalized amplitude factor instead of constant value 0.033. The free space optical communication performance for a Gaussian beam wave of scintillation index, mean signal-to-noise ratio , and mean bit error rate , have been derived by extended Rytov theory in non-Kolmogorov strong turbulence. And then the influence of wind speed variations on free space optical communication performance has been analyzed under different atmospheric turbulence intensities. The results suggest that the effects of wind speed variation through non-Kolmogorov turbulence on communication performance are more severe in many situations and need to be taken into account in free space optical communication. It is anticipated that this work is helpful to the investigations of free space optical communication performance considering wind speed under severe weather condition in the strong atmospheric turbulence.

A Multi-Point Method Considering the Maximum Power Point Tracking Dynamic Process for Aerodynamic Optimization of Variable-Speed Wind Turbine Blades

Directory of Open Access Journals (Sweden)

Zhiqiang Yang

2016-05-01

Full Text Available Due to the dynamic process of maximum power point tracking (MPPT caused by turbulence and large rotor inertia, variable-speed wind turbines (VSWTs cannot maintain the optimal tip speed ratio (TSR from cut-in wind speed up to the rated speed. Therefore, in order to increase the total captured wind energy, the existing aerodynamic design for VSWT blades, which only focuses on performance improvement at a single TSR, needs to be improved to a multi-point design. In this paper, based on a closed-loop system of VSWTs, including turbulent wind, rotor, drive train and MPPT controller, the distribution of operational TSR and its description based on inflow wind energy are investigated. Moreover, a multi-point method considering the MPPT dynamic process for the aerodynamic optimization of VSWT blades is proposed. In the proposed method, the distribution of operational TSR is obtained through a dynamic simulation of the closed-loop system under a specific turbulent wind, and accordingly the multiple design TSRs and the corresponding weighting coefficients in the objective function are determined. Finally, using the blade of a National Renewable Energy Laboratory (NREL 1.5 MW wind turbine as the baseline, the proposed method is compared with the conventional single-point optimization method using the commercial software Bladed. Simulation results verify the effectiveness of the proposed method.

Improved Mobility Performance in LTE Co-Channel HetNets Through Speed Differentiated Enhancements

DEFF Research Database (Denmark)

Barbera, Simone; Michaelsen, Per Henrik; Säily, Mikko

2012-01-01

, requiring minimum assistance and signaling from the network. Extensive system level simulations are used to quantify the benefits. Results confirm that the proposed solutions offer improvements in several mobility key performance indicators such as radio link failure, number of handovers, offload to pico......This paper analyzes the mobility performance of LTE (Long Term Evolution) co-channel heterogeneous networks (HetNet) with macro and pico cells. Improved methods for differentiating offload and mobility robustness as a function of the UE (User Equipment) mobility are proposed. The suggested solution...... comprises two key elements, namely enhanced UE MSE (Mobility State Estimation), as well as optimized methods such that high speed users are primarily kept at the macro layer, while the offload to pico cells for low speed users is maximized. The proposed methods are designed as UE autonomous solutions...

Machining tools in AISI M2 high-speed steel obtained by spray forming process

International Nuclear Information System (INIS)

Jesus, Edilson Rosa Barbosa de.

2004-01-01

The aim of the present work was the obtention of AISI M2 high-speed steel by spray forming technique and the material evaluation when used as machining tool. The obtained material was hot rolled at 50% and 72% reduction ratios, and from which it was manufactured inserts for machining tests. The performance of inserts made of the spray formed material was compared to inserts obtained from conventional and powder metallurgy (MP) processed materials. The spray formed material was chemical, physical, mechanical and microstructural characterised. For further characterisation, the materials were submitted to machining tests for performance evaluation under real work condition. The results of material characterisation highlight the potential of the spray forming technique, in the obtention of materials with good characteristics and properties. Under the current processing, hot rolling and heat treatments condition, the analysis of the results of the machining tests revealed a very similar behaviour among the tested materials. Proceeding a criterious analysis of the machining results tests, it was verified that the performance presented by the powder metallurgy material (MP) was slight superior, followed by conventional obtained material (MConv), which presented a insignificant advantage over the spray formed and hot rolled (72% reduction ratio) material. The worst result was encountered for the spray forming and hot rolled (50% reduction ratio) material that presented the highest wear values. (author)

Examining Impulse-Variability Theory and the Speed-Accuracy Trade-Off in Children's Overarm Throwing Performance.

Science.gov (United States)

Molina, Sergio L; Stodden, David F

2018-04-01

This study examined variability in throwing speed and spatial error to test the prediction of an inverted-U function (i.e., impulse-variability [IV] theory) and the speed-accuracy trade-off. Forty-five 9- to 11-year-old children were instructed to throw at a specified percentage of maximum speed (45%, 65%, 85%, and 100%) and hit the wall target. Results indicated no statistically significant differences in variable error across the target conditions (p = .72), failing to support the inverted-U hypothesis. Spatial accuracy results indicated no statistically significant differences with mean radial error (p = .18), centroid radial error (p = .13), and bivariate variable error (p = .08) also failing to support the speed-accuracy trade-off in overarm throwing. As neither throwing performance variability nor accuracy changed across percentages of maximum speed in this sample of children as well as in a previous adult sample, current policy and practices of practitioners may need to be reevaluated.

Clusters of PCS for high-speed computation for modelling of the climate

International Nuclear Information System (INIS)

Pabon C, Jose Daniel; Eslava R, Jesus Antonio; Montoya G, Gerardo de Jesus

2001-01-01

In order to create high speed computing capability, the Program of Post grade in Meteorology of the Department of Geosciences, National University of Colombia installed a cluster of 8 PCs for parallel processing. This high-speed processing machine was tested with the Climate Community Model (CCM3). In this paper, the results related to the performance of this machine are presented

Information processing speed as a predictor of IQ in children with and without specific language impairment in grades 3 and 8.

Science.gov (United States)

Park, Jisook; Mainela-Arnold, Elina; Miller, Carol A

2015-01-01

This study investigated (1) whether nonlinguistic processing speed predicts nonverbal IQ in TD children and children with SLI and (2) if the proposed relationship is different at two time points. The participants consisted of a subset of a longitudinal dataset, 55 typically developing children and 55 children with SLI. Children completed four nonverbal speed tasks and four subtests of the WISC-III. The WISC-III subtests requiring timed and untimed responses were examined separately. Linear mixed model analyses indicated that in both groups, processing speed predicted nonverbal IQ subtests that reward speedy responses, but not IQ subtests that do not. The relationships between processing speed and IQ with speed bonuses did not differ at grades 3 and 8, and these relationships also were not significantly different in children with SLI and their TD peers. The results suggest that the presence of processing speed limitations in many children with SLI raises questions about the utility of timed nonverbal IQ measures as tools for diagnosis of SLI. Future studies should investigate other cognitive assessments that could be used as inclusionary criteria for SLI. The reader will be able to (1) describe the relationship between processing speed and nonverbal IQ in children with TD and SLI and (2) discuss problems using an IQ criterion to diagnose children as having SLI. Copyright © 2014 Elsevier Inc. All rights reserved.

A high-speed tunable beam splitter for feed-forward photonic quantum information processing.

Science.gov (United States)

Ma, Xiao-Song; Zotter, Stefan; Tetik, Nuray; Qarry, Angie; Jennewein, Thomas; Zeilinger, Anton

2011-11-07

We realize quantum gates for path qubits with a high-speed, polarization-independent and tunable beam splitter. Two electro-optical modulators act in a Mach-Zehnder interferometer as high-speed phase shifters and rapidly tune its splitting ratio. We test its performance with heralded single photons, observing a polarization-independent interference contrast above 95%. The switching time is about 5.6 ns, and a maximal repetition rate is 2.5 MHz. We demonstrate tunable feed-forward operations of a single-qubit gate of path-encoded qubits and a two-qubit gate via measurement-induced interaction between two photons.

Structure Design and Performance Analysis of High-Speed Miniature Ball Bearing

Science.gov (United States)

Li, Songsheng; Zhang, Guoye; Chen, Bin; Shen, Yuan

2017-07-01

The working performances of miniature ball bearings are obviously affected by its’ geometric structure parameters. In this paper, quasi-static analysis theory is applied in the design of miniature ball bearings. Firstly, it is studied the influence of geometry structure, preload and rotating speed on the dynamic performance of bearing. Secondly, bearing dynamic characteristics are analyzed which include the bearing stiffness and Spin to roll Ratio. Lastly, the contact stress and bearing life are calculated. The results indicate that structure parameters play an importance role in bearing’s dynamic performances. Miniature ball bearings which have lager ball number, bigger ball diameter and smaller inner race groove radius can get better performances while velocity and preload have great impact on the bearing life. So that parameters of miniature bearing should be chosen cautiously.

High-Speed Data Recorder for Space, Geodesy, and Other High-Speed Recording Applications

Science.gov (United States)

Taveniku, Mikael

2013-01-01

A high-speed data recorder and replay equipment has been developed for reliable high-data-rate recording to disk media. It solves problems with slow or faulty disks, multiple disk insertions, high-altitude operation, reliable performance using COTS hardware, and long-term maintenance and upgrade path challenges. The current generation data recor - ders used within the VLBI community are aging, special-purpose machines that are both slow (do not meet today's requirements) and are very expensive to maintain and operate. Furthermore, they are not easily upgraded to take advantage of commercial technology development, and are not scalable to multiple 10s of Gbit/s data rates required by new applications. The innovation provides a softwaredefined, high-speed data recorder that is scalable with technology advances in the commercial space. It maximally utilizes current technologies without being locked to a particular hardware platform. The innovation also provides a cost-effective way of streaming large amounts of data from sensors to disk, enabling many applications to store raw sensor data and perform post and signal processing offline. This recording system will be applicable to many applications needing realworld, high-speed data collection, including electronic warfare, softwaredefined radar, signal history storage of multispectral sensors, development of autonomous vehicles, and more.

Performance analysis of InSb based QWFET for ultra high speed applications

International Nuclear Information System (INIS)

Subash, T. D.; Gnanasekaran, T.; Divya, C.

2015-01-01

An indium antimonide based QWFET (quantum well field effect transistor) with the gate length down to 50 nm has been designed and investigated for the first time for L-band radar applications at 230 GHz. QWFETs are designed at the high performance node of the International Technology Road Map for Semiconductors (ITRS) requirements of drive current (Semiconductor Industry Association 2010). The performance of the device is investigated using the SYNOPSYS CAD (TCAD) software. InSb based QWFET could be a promising device technology for very low power and ultra-high speed performance with 5–10 times low DC power dissipation. (semiconductor devices)

Performance comparison of control schemes for variable-speed wind turbines

Science.gov (United States)

Bottasso, C. L.; Croce, A.; Savini, B.

2007-07-01

We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies.

Performance comparison of control schemes for variable-speed wind turbines

International Nuclear Information System (INIS)

Bottasso, C L; Croce, A; Savini, B

2007-01-01

We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies

Improving Working Memory and Processing Speed of Students with Dyslexia in Nigeria

Science.gov (United States)

Adubasim, Ijeoma

2018-01-01

This study investigated effective strategies for improving working memory and processing speed of students identified with dyslexia in Nigeria. The study adopted a quasi-experimental research design with the population made up of twenty four thousand seven hundred and twenty seven (24,727) senior secondary school students (S.S.2) in all the public…

How Accumulated Real Life Stress Experience and Cognitive Speed Interact on Decision-Making Processes

Directory of Open Access Journals (Sweden)

Eva Friedel

2017-06-01

Full Text Available Rationale: Advances in neurocomputational modeling suggest that valuation systems for goal-directed (deliberative on one side, and habitual (automatic decision-making on the other side may rely on distinct computational strategies for reinforcement learning, namely model-free vs. model-based learning. As a key theoretical difference, the model-based system strongly demands cognitive functions to plan actions prospectively based on an internal cognitive model of the environment, whereas valuation in the model-free system relies on rather simple learning rules from operant conditioning to retrospectively associate actions with their outcomes and is thus cognitively less demanding. Acute stress reactivity is known to impair model-based but not model-free choice behavior, with higher working memory capacity protecting the model-based system from acute stress. However, it is not clear which impact accumulated real life stress has on model-free and model-based decision systems and how this influence interacts with cognitive abilities.Methods: We used a sequential decision-making task distinguishing relative contributions of both learning strategies to choice behavior, the Social Readjustment Rating Scale questionnaire to assess accumulated real life stress, and the Digit Symbol Substitution Test to test cognitive speed in 95 healthy subjects.Results: Individuals reporting high stress exposure who had low cognitive speed showed reduced model-based but increased model-free behavioral control. In contrast, subjects exposed to accumulated real life stress with high cognitive speed displayed increased model-based performance but reduced model-free control.Conclusion: These findings suggest that accumulated real life stress exposure can enhance reliance on cognitive speed for model-based computations, which may ultimately protect the model-based system from the detrimental influences of accumulated real life stress. The combination of accumulated real life

How Accumulated Real Life Stress Experience and Cognitive Speed Interact on Decision-Making Processes.

Science.gov (United States)

Friedel, Eva; Sebold, Miriam; Kuitunen-Paul, Sören; Nebe, Stephan; Veer, Ilya M; Zimmermann, Ulrich S; Schlagenhauf, Florian; Smolka, Michael N; Rapp, Michael; Walter, Henrik; Heinz, Andreas

2017-01-01

Rationale: Advances in neurocomputational modeling suggest that valuation systems for goal-directed (deliberative) on one side, and habitual (automatic) decision-making on the other side may rely on distinct computational strategies for reinforcement learning, namely model-free vs. model-based learning. As a key theoretical difference, the model-based system strongly demands cognitive functions to plan actions prospectively based on an internal cognitive model of the environment, whereas valuation in the model-free system relies on rather simple learning rules from operant conditioning to retrospectively associate actions with their outcomes and is thus cognitively less demanding. Acute stress reactivity is known to impair model-based but not model-free choice behavior, with higher working memory capacity protecting the model-based system from acute stress. However, it is not clear which impact accumulated real life stress has on model-free and model-based decision systems and how this influence interacts with cognitive abilities. Methods: We used a sequential decision-making task distinguishing relative contributions of both learning strategies to choice behavior, the Social Readjustment Rating Scale questionnaire to assess accumulated real life stress, and the Digit Symbol Substitution Test to test cognitive speed in 95 healthy subjects. Results: Individuals reporting high stress exposure who had low cognitive speed showed reduced model-based but increased model-free behavioral control. In contrast, subjects exposed to accumulated real life stress with high cognitive speed displayed increased model-based performance but reduced model-free control. Conclusion: These findings suggest that accumulated real life stress exposure can enhance reliance on cognitive speed for model-based computations, which may ultimately protect the model-based system from the detrimental influences of accumulated real life stress. The combination of accumulated real life stress exposure

Short-term Periodization Models: Effects on Strength and Speed-strength Performance.

Science.gov (United States)

Hartmann, Hagen; Wirth, Klaus; Keiner, Michael; Mickel, Christoph; Sander, Andre; Szilvas, Elena

2015-10-01

Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant decreasing volume, converging to peak intensity (peaking phase). Undulating periodization strategies rotate these program variables in a bi-weekly, weekly, or daily fashion. The following review addresses the effects of different short-term periodization models on strength and speed-strength both with subjects of different performance levels and with competitive athletes from different sports who use a particular periodization model during off-season, pre-season, and in-season conditioning. In most periodization studies, it is obvious that the strength endurance sessions are characterized by repetition zones (12-15 repetitions) that induce muscle hypertrophy in persons with a low performance level. Strictly speaking, when examining subjects with a low training level, many periodization studies include mainly hypertrophy sessions interspersed with heavy strength/power sessions. Studies have demonstrated equal or statistically significant higher gains in maximal strength for daily undulating periodization compared with SPP in subjects with a low to moderate performance level. The relatively short intervention period and the lack of concomitant sports conditioning call into question the practical value of these findings for competitive athletes. Possibly owing to differences in mesocycle length, conditioning programs, and program variables, competitive athletes either maintained or improved strength and/or speed-strength performance by integrating daily undulating periodization and SPP during off-season, pre-season and in-season conditioning. In high-performance sports, high-repetition strength training (>15) should be

In situ flash x-ray high-speed computed tomography for the quantitative analysis of highly dynamic processes

Science.gov (United States)

Moser, Stefan; Nau, Siegfried; Salk, Manfred; Thoma, Klaus

2014-02-01

The in situ investigation of dynamic events, ranging from car crash to ballistics, often is key to the understanding of dynamic material behavior. In many cases the important processes and interactions happen on the scale of milli- to microseconds at speeds of 1000 m s-1 or more. Often, 3D information is necessary to fully capture and analyze all relevant effects. High-speed 3D-visualization techniques are thus required for the in situ analysis. 3D-capable optical high-speed methods often are impaired by luminous effects and dust, while flash x-ray based methods usually deliver only 2D data. In this paper, a novel 3D-capable flash x-ray based method, in situ flash x-ray high-speed computed tomography is presented. The method is capable of producing 3D reconstructions of high-speed processes based on an undersampled dataset consisting of only a few (typically 3 to 6) x-ray projections. The major challenges are identified, discussed and the chosen solution outlined. The application is illustrated with an exemplary application of a 1000 m s-1 high-speed impact event on the scale of microseconds. A quantitative analysis of the in situ measurement of the material fragments with a 3D reconstruction with 1 mm voxel size is presented and the results are discussed. The results show that the HSCT method allows gaining valuable visual and quantitative mechanical information for the understanding and interpretation of high-speed events.

An improvement of speed control performances of a two-mass system using a universal approximator

DEFF Research Database (Denmark)

Lee, Kyo Beum; Blåbjerg, Frede

2007-01-01

A new control scheme using a universal approximator based on a radial basis ti.tnction network (RBFN) is proposed and investigated for improving the control characteristics of the high-performance motion control system. This control method presents better performance in the corresponding speed vi...

Performance predictions affect attentional processes of event-based prospective memory.

Science.gov (United States)

Rummel, Jan; Kuhlmann, Beatrice G; Touron, Dayna R

2013-09-01

To investigate whether making performance predictions affects prospective memory (PM) processing, we asked one group of participants to predict their performance in a PM task embedded in an ongoing task and compared their performance with a control group that made no predictions. A third group gave not only PM predictions but also ongoing-task predictions. Exclusive PM predictions resulted in slower ongoing-task responding both in a nonfocal (Experiment 1) and in a focal (Experiment 2) PM task. Only in the nonfocal task was the additional slowing accompanied by improved PM performance. Even in the nonfocal task, however, was the correlation between ongoing-task speed and PM performance reduced after predictions, suggesting that the slowing was not completely functional for PM. Prediction-induced changes could be avoided by asking participants to additionally predict their performance in the ongoing task. In sum, the present findings substantiate a role of metamemory for attention-allocation strategies of PM. Copyright © 2013 Elsevier Inc. All rights reserved.

A Method for Speeding Up Value Iteration in Partially Observable Markov Decision Processes

OpenAIRE

Zhang, Nevin Lianwen; Lee, Stephen S.; Zhang, Weihong

2013-01-01

We present a technique for speeding up the convergence of value iteration for partially observable Markov decisions processes (POMDPs). The underlying idea is similar to that behind modified policy iteration for fully observable Markov decision processes (MDPs). The technique can be easily incorporated into any existing POMDP value iteration algorithms. Experiments have been conducted on several test problems with one POMDP value iteration algorithm called incremental pruning. We find that th...

Visual temporal processing in dyslexia and the magnocellular deficit theory: the need for speed?

Science.gov (United States)

McLean, Gregor M T; Stuart, Geoffrey W; Coltheart, Veronika; Castles, Anne

2011-12-01

A controversial question in reading research is whether dyslexia is associated with impairments in the magnocellular system and, if so, how these low-level visual impairments might affect reading acquisition. This study used a novel chromatic flicker perception task to specifically explore temporal aspects of magnocellular functioning in 40 children with dyslexia and 42 age-matched controls (aged 7-11). The relationship between magnocellular temporal resolution and higher-level aspects of visual temporal processing including inspection time, single and dual-target (attentional blink) RSVP performance, go/no-go reaction time, and rapid naming was also assessed. The Dyslexia group exhibited significant deficits in magnocellular temporal resolution compared with controls, but the two groups did not differ in parvocellular temporal resolution. Despite the significant group differences, associations between magnocellular temporal resolution and reading ability were relatively weak, and links between low-level temporal resolution and reading ability did not appear specific to the magnocellular system. Factor analyses revealed that a collective Perceptual Speed factor, involving both low-level and higher-level visual temporal processing measures, accounted for unique variance in reading ability independently of phonological processing, rapid naming, and general ability.

Visual tracking speed is related to basketball-specific measures of performance in NBA players.

Science.gov (United States)

Mangine, Gerald T; Hoffman, Jay R; Wells, Adam J; Gonzalez, Adam M; Rogowski, Joseph P; Townsend, Jeremy R; Jajtner, Adam R; Beyer, Kyle S; Bohner, Jonathan D; Pruna, Gabriel J; Fragala, Maren S; Stout, Jeffrey R

2014-09-01

The purpose of this study was to determine the relationship between visual tracking speed (VTS) and reaction time (RT) on basketball-specific measures of performance. Twelve professional basketball players were tested before the 2012-13 season. Visual tracking speed was obtained from 1 core session (20 trials) of the multiple object tracking test, whereas RT was measured by fixed- and variable-region choice reaction tests, using a light-based testing device. Performance in VTS and RT was compared with basketball-specific measures of performance (assists [AST]; turnovers [TO]; assist-to-turnover ratio [AST/TO]; steals [STL]) during the regular basketball season. All performance measures were reported per 100 minutes played. Performance differences between backcourt (guards; n = 5) and frontcourt (forward/centers; n = 7) positions were also examined. Relationships were most likely present between VTS and AST (r = 0.78; p basketball-specific performance measures. Backcourt players were most likely to outperform frontcourt players in AST and very likely to do so for VTS, TO, and AST/TO. In conclusion, VTS seems to be related to a basketball player's ability to see and respond to various stimuli on the basketball court that results in more positive plays as reflected by greater number of AST and STL and lower turnovers.

Tip Speed Ratio Based Maximum Power Tracking Control of Variable Speed Wind Turbines; A Comprehensive Design

Directory of Open Access Journals (Sweden)

Murat Karabacak

2017-08-01

Full Text Available The most primitive control method of wind turbines used to generate electric energy from wind is the fixed speed control method. With this method, it is not possible that turbine input power is transferred to grid at maximum rate. For this reason, Maximum Power Tracking (MPT schemes are proposed. In order to implement MPT, the propeller has to rotate at a different speed for every different wind speed. This situation has led MPT based systems to be called Variable Speed Wind Turbine (VSWT systems. In VSWT systems, turbine input power can be transferred to grid at rates close to maximum power. When MPT based control of VSWT systems is the case, two important processes come into prominence. These are instantaneously determination and tracking of MPT point. In this study, using a Maximum Power Point Tracking (MPPT method based on tip speed ratio, power available in wind is transferred into grid over a back to back converter at maximum rate via a VSWT system with permanent magnet synchronous generator (PMSG. Besides a physical wind turbine simulator is modelled and simulated. Results show that a time varying MPPT point is tracked with a high performance.

Sensorless FOC Performance Improved with On-Line Speed and Rotor Resistance Estimator Based on an Artificial Neural Network for an Induction Motor Drive

Directory of Open Access Journals (Sweden)

Jose. M. Gutierrez-Villalobos

2015-06-01

Full Text Available Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor.

SPEEDES - A multiple-synchronization environment for parallel discrete-event simulation

Science.gov (United States)

Steinman, Jeff S.

1992-01-01

Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES) is a unified parallel simulation environment. It supports multiple-synchronization protocols without requiring users to recompile their code. When a SPEEDES simulation runs on one node, all the extra parallel overhead is removed automatically at run time. When the same executable runs in parallel, the user preselects the synchronization algorithm from a list of options. SPEEDES currently runs on UNIX networks and on the California Institute of Technology/Jet Propulsion Laboratory Mark III Hypercube. SPEEDES also supports interactive simulations. Featured in the SPEEDES environment is a new parallel synchronization approach called Breathing Time Buckets. This algorithm uses some of the conservative techniques found in Time Bucket synchronization, along with the optimism that characterizes the Time Warp approach. A mathematical model derived from first principles predicts the performance of Breathing Time Buckets. Along with the Breathing Time Buckets algorithm, this paper discusses the rules for processing events in SPEEDES, describes the implementation of various other synchronization protocols supported by SPEEDES, describes some new ones for the future, discusses interactive simulations, and then gives some performance results.

A Gaussian process regression based hybrid approach for short-term wind speed prediction

International Nuclear Information System (INIS)

Zhang, Chi; Wei, Haikun; Zhao, Xin; Liu, Tianhong; Zhang, Kanjian

2016-01-01

Highlights: • A novel hybrid approach is proposed for short-term wind speed prediction. • This method combines the parametric AR model with the non-parametric GPR model. • The relative importance of different inputs is considered. • Different types of covariance functions are considered and combined. • It can provide both accurate point forecasts and satisfactory prediction intervals. - Abstract: This paper proposes a hybrid model based on autoregressive (AR) model and Gaussian process regression (GPR) for probabilistic wind speed forecasting. In the proposed approach, the AR model is employed to capture the overall structure from wind speed series, and the GPR is adopted to extract the local structure. Additionally, automatic relevance determination (ARD) is used to take into account the relative importance of different inputs, and different types of covariance functions are combined to capture the characteristics of the data. The proposed hybrid model is compared with the persistence model, artificial neural network (ANN), and support vector machine (SVM) for one-step ahead forecasting, using wind speed data collected from three wind farms in China. The forecasting results indicate that the proposed method can not only improve point forecasts compared with other methods, but also generate satisfactory prediction intervals.

Hydraulic performance of a low specific speed centrifugal pump with Spanwise-Slotted Blades

International Nuclear Information System (INIS)

Ye, D X; Li, H; Wang, Y

2013-01-01

The hydraulic efficiency of a low specific speed centrifugal pump is low because of the long and narrow meridian flow passage, and the severe disk friction. Spanwise slotted blade flow control technology has been applied to the low specific speed centrifugal pump. This paper concluded that spanwise slotted blades can improve the pump performance in both experiments and simulations. In order to study the influence to the impeller and volute by spanwise slotted blade, impeller efficiency and volute efficiency were defined. The minimum volute efficiency and the maximum pump efficiency appear at the same time in the design flow condition in the unsteady simulation. The mechanism of spanwise slotted blade flow control technology should be researched furthermore

Dietary self-control is related to the speed with which attributes of healthfulness and tastiness are processed.

Science.gov (United States)

Sullivan, Nicolette; Hutcherson, Cendri; Harris, Alison; Rangel, Antonio

2015-02-01

We propose that self-control failures, and variation across individuals in self-control abilities, are partly due to differences in the speed with which the decision-making circuitry processes basic attributes, such as tastiness, versus more abstract attributes, such as healthfulness. We tested these hypotheses by combining a dietary-choice task with a novel form of mouse tracking that allowed us to pinpoint when different attributes were being integrated into the choice process with temporal resolution at the millisecond level. We found that, on average, tastiness was processed about 195 ms earlier than healthfulness during the choice process. We also found that 13% to 39% of observed individual differences in self-control ability could be explained by differences in the relative speed with which tastiness and healthfulness were processed. © The Author(s) 2014.

The Effect of Two Speed Endurance Training Regimes on Performance of Soccer Players.

Directory of Open Access Journals (Sweden)

F Marcello Iaia

Full Text Available In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players (age 18.5±1 yr, height 179.5±6.5 cm, body mass 74.3±6.5 kg reduced the training volume by ~20% and replaced their habitual fitness conditioning work with either speed endurance production (SEP; n = 6 or speed endurance maintenance (SEM; n = 7 training, three times per wk. SEP training consisted of 6-8 reps of 20-s all-out running bouts followed by 2 min of passive recovery, whereas SEM training was characterized by 6-8 x 20-s all-out efforts interspersed with 40 s of passive recovery. SEP training reduced (p<0.01 the total time in a repeated sprint ability test (RSAt by 2.5%. SEM training improved the 200-m sprint performance (from 26.59±0.70 to 26.02±0.62 s, p<0.01 and had a likely beneficial impact on the percentage decrement score of the RSA test (from 4.07±1.28 to 3.55±1.01% but induced a very likely impairment in RSAt (from 83.81±2.37 to 84.65±2.27 s. The distance covered in the Yo-Yo Intermittent Recovery test level 2 was 10.1% (p<0.001 and 3.8% (p<0.05 higher after SEP and SEM training, respectively, with possibly greater improvements following SEP compared to SEM. No differences were observed in the 20- and 40-m sprint performances. In conclusion, these two training strategies target different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles' ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in

Hierarchically porous carbon with high-speed ion transport channels for high performance supercapacitors

Science.gov (United States)

Lu, Haoyuan; Li, Qingwei; Guo, Jianhui; Song, Aixin; Gong, Chunhong; Zhang, Jiwei; Zhang, Jingwei

2018-01-01

Hierarchically porous carbons (HPC) are considered as promising electrode materials for supercapacitors, due to their outstanding charge/discharge cycling stabilities and high power densities. However, HPC possess a relatively low ion diffusion rate inside the materials, which challenges their application for high performance supercapacitor. Thus tunnel-shaped carbon pores with a size of tens of nanometers were constructed by inducing the self-assembly of lithocholic acid with ammonium chloride, thereby providing high-speed channels for internal ion diffusion. The as-formed one-dimensional pores are beneficial to the activation process by KOH, providing a large specific surface area, and then facilitate rapid transport of electrolyte ions from macropores to the microporous surfaces. Therefore, the HPC achieve an outstanding gravimetric capacitance of 284 F g-1 at a current density of 0.1 A g-1 and a remarkable capacity retention of 64.8% when the current density increases by 1000 times to 100 A g-1.

Verbal fluency in male and female schizophrenia patients: Different patterns of association with processing speed, working memory span, and clinical symptoms.

Science.gov (United States)

Brébion, Gildas; Stephan-Otto, Christian; Ochoa, Susana; Nieto, Lourdes; Contel, Montserrat; Usall, Judith

2018-01-01

Decreased processing speed in schizophrenia patients has been identified as a major impairment factor in various neuropsychological domains. Working memory span has been found to be involved in several deep or effortful cognitive processes. We investigated the impact that these 2 cognitive functions may have on phonological and semantic fluency in schizophrenia patients and healthy participants. Fifty-five patients with schizophrenia and 60 healthy participants were administered a neuropsychological battery including phonological and semantic fluency, working memory, and cognitive and motor speed. Regression analyses revealed that motor speed was related to phonological fluency in female patients, whereas cognitive speed was related to semantic fluency in male patients. In addition, working memory span was related to verbal fluency in women from both the patient and the healthy control groups. Decreased processing speed, but not decreased working memory span, accounted for the verbal fluency deficit in patients. Verbal fluency was inversely related to attention deficit in female patients and to negative symptoms in male patients. Decreased processing speed may be the main factor in verbal fluency impairment of patients. Further, the cognitive and clinical predictors of verbal fluency efficiency are different in men and women. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Comparison of Statistical Post-Processing Methods for Probabilistic Wind Speed Forecasting

Science.gov (United States)

Han, Keunhee; Choi, JunTae; Kim, Chansoo

2018-02-01

In this study, the statistical post-processing methods that include bias-corrected and probabilistic forecasts of wind speed measured in PyeongChang, which is scheduled to host the 2018 Winter Olympics, are compared and analyzed to provide more accurate weather information. The six post-processing methods used in this study are as follows: mean bias-corrected forecast, mean and variance bias-corrected forecast, decaying averaging forecast, mean absolute bias-corrected forecast, and the alternative implementations of ensemble model output statistics (EMOS) and Bayesian model averaging (BMA) models, which are EMOS and BMA exchangeable models by assuming exchangeable ensemble members and simplified version of EMOS and BMA models. Observations for wind speed were obtained from the 26 stations in PyeongChang and 51 ensemble member forecasts derived from the European Centre for Medium-Range Weather Forecasts (ECMWF Directorate, 2012) that were obtained between 1 May 2013 and 18 March 2016. Prior to applying the post-processing methods, reliability analysis was conducted by using rank histograms to identify the statistical consistency of ensemble forecast and corresponding observations. Based on the results of our study, we found that the prediction skills of probabilistic forecasts of EMOS and BMA models were superior to the biascorrected forecasts in terms of deterministic prediction, whereas in probabilistic prediction, BMA models showed better prediction skill than EMOS. Even though the simplified version of BMA model exhibited best prediction skill among the mentioned six methods, the results showed that the differences of prediction skills between the versions of EMOS and BMA were negligible.

Dual N-Back Working Memory Training in Healthy Adults: A Randomized Comparison to Processing Speed Training

Science.gov (United States)

Lawlor-Savage, Linette; Goghari, Vina M.

2016-01-01

Enhancing cognitive ability is an attractive concept, particularly for middle-aged adults interested in maintaining cognitive functioning and preventing age-related declines. Computerized working memory training has been investigated as a safe method of cognitive enhancement in younger and older adults, although few studies have considered the potential impact of working memory training on middle-aged adults. This study investigated dual n-back working memory training in healthy adults aged 30–60. Fifty-seven adults completed measures of working memory, processing speed, and fluid intelligence before and after a 5-week web-based dual n-back or active control (processing speed) training program. Results: Repeated measures multivariate analysis of variance failed to identify improvements across the three cognitive composites, working memory, processing speed, and fluid intelligence, after training. Follow-up Bayesian analyses supported null findings for training effects for each individual composite. Findings suggest that dual n-back working memory training may not benefit working memory or fluid intelligence in healthy adults. Further investigation is necessary to clarify if other forms of working memory training may be beneficial, and what factors impact training-related benefits, should they occur, in this population. PMID:27043141

Dual N-Back Working Memory Training in Healthy Adults: A Randomized Comparison to Processing Speed Training.

Directory of Open Access Journals (Sweden)

Linette Lawlor-Savage

Full Text Available Enhancing cognitive ability is an attractive concept, particularly for middle-aged adults interested in maintaining cognitive functioning and preventing age-related declines. Computerized working memory training has been investigated as a safe method of cognitive enhancement in younger and older adults, although few studies have considered the potential impact of working memory training on middle-aged adults. This study investigated dual n-back working memory training in healthy adults aged 30-60. Fifty-seven adults completed measures of working memory, processing speed, and fluid intelligence before and after a 5-week web-based dual n-back or active control (processing speed training program.Repeated measures multivariate analysis of variance failed to identify improvements across the three cognitive composites, working memory, processing speed, and fluid intelligence, after training. Follow-up Bayesian analyses supported null findings for training effects for each individual composite. Findings suggest that dual n-back working memory training may not benefit working memory or fluid intelligence in healthy adults. Further investigation is necessary to clarify if other forms of working memory training may be beneficial, and what factors impact training-related benefits, should they occur, in this population.

Speed and income

DEFF Research Database (Denmark)

Fosgerau, Mogens

2005-01-01

The relationship between speed and income is established in a microeconomic model focusing on the trade-off between travel time and the risk of receiving a penalty for exceeding the speed limit. This is used to determine when a rational driver will choose to exceed the speed limit. The relationship...... between speed and income is found again in the empirical analysis of a cross-sectional dataset comprising 60,000 observations of car trips. This is used to perform regressions of speed on income, distance travelled, and a number of controls. The results are clearly statistically significant and indicate...... an average income elasticity of speed of 0.02; it is smaller at short distances and about twice as large at the longest distance investigated of 200 km....

Influence of RZ and NRZ signal format on the high-speed performance of gain-clamped semiconductor optical amplifiers

DEFF Research Database (Denmark)

Fjelde, Tina; Wolfson, David; Kloch, Allan

2000-01-01

High-speed experiments show that the influence from the limited relaxation frequency of GC-SOAs that severely degrades the performance for NRZ signals is reduced by using RZ signals, thus resulting in a higher input power dynamic range.......High-speed experiments show that the influence from the limited relaxation frequency of GC-SOAs that severely degrades the performance for NRZ signals is reduced by using RZ signals, thus resulting in a higher input power dynamic range....

The effect of two speed endurance training regimes on performance of soccer players

DEFF Research Database (Denmark)

Iaia, F Marcello; Fiorenza, Matteo; Perri, Enrico

2015-01-01

In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players...... different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles' ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short......-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in trained young soccer players....

Balancing Biomechanical Constraints: Optimal Escape Speeds When There Is a Trade-off between Speed and Maneuverability.

Science.gov (United States)

Clemente, C J; Wilson, R S

2015-12-01

The ability for prey to escape a pursuing predator is dependent both on the prey's speed away from the threat and on their ability to rapidly change directions, or maneuverability. Given that the biomechanical trade-off between speed and maneuverability limits the simultaneous maximization of both performance traits, animals should not select their fastest possible speeds when running away from a pursuing predator but rather a speed that maximizes the probability of successful escape. We explored how variation in the relationship between speed and maneuverability-or the shape of the trade-off-affects the optimal choice of speed for escaping predators. We used tablet-based games that simulated interactions between predators and prey (human subjects acting as predators attempting to capture "prey" moving across a screen). By defining a specific relationship between speed and maneuverability, we could test the survival of each of the possible behavioral choices available to this phenotype, i.e., the best combination of speed and maneuverability for prey fitness, based on their ability to escape. We found that the shape of the trade-off function affected the prey's optimal speed for success in escaping, the prey's maximum performance in escaping, and the breadth of speeds over which the prey's performance was high. The optimal speed for escape varied only when the trade-off between speed and maneuverability was non-linear. Phenotypes possessing trade-off functions for which maneuverability was only compromised at high speeds exhibited lower optimal speeds. Phenotypes that exhibited greater increases in maneuverability for any decrease in speed were more likely to have broader ranges of performance, meaning that individuals could attain their maximum performance across a broader range of speeds. We also found that there was a differential response of the subject's learning to these different components of locomotion. With increased experience through repeated trials

Gender-specific influences of balance, speed, and power on agility performance.

Science.gov (United States)

Sekulic, Damir; Spasic, Miodrag; Mirkov, Dragan; Cavar, Mile; Sattler, Tine

2013-03-01

The quick change of direction (i.e., agility) is an important athletic ability in numerous sports. Because of the diverse and therefore hardly predictable manifestations of agility in sports, studies noted that the improvement in speed, power, and balance should result in an improvement of agility. However, there is evident lack of data regarding the influence of potential predictors on different agility manifestations. The aim of this study was to determine the gender-specific influence of speed, power, and balance on different agility tests. A total of 32 college-aged male athletes and 31 college-aged female athletes (age 20.02 ± 1.89 years) participated in this study. The subjects were mostly involved in team sports (soccer, team handball, basketball, and volleyball; 80% of men, and 75% of women), martial arts, gymnastics, and dance. Anthropometric variables consisted of body height, body weight, and the body mass index. Five agility tests were used: a t-test (T-TEST), zig-zag test, 20-yard shuttle test, agility test with a 180-degree turn, and forward-backward running agility test (FWDBWD). Other tests included 1 jumping ability power test (squat jump, SQJ), 2 balance tests to determine the overall stability index and an overall limit of stability score (both measured by Biodex Balance System), and 2 running speed tests using a straight sprint for 10 and 20 m (S10 and S20, respectively). A reliability analysis showed that all the agility tests were reliable. Multiple regression and correlation analysis found speed and power (among women), and balance (among men), as most significant predictors of agility. The highest Pearson's correlation in both genders is found between the results of the FWDBWD and S10M tests (0.77 and 0.81 for men and women, respectively; p Power, measured using the SQJ, is significantly (p balance measures were significantly related to the agility performance for men but not for women. In addition to demonstrating a known relationship

fMRI evidence for a dual process account of the speed-accuracy tradeoff in decision-making.

Directory of Open Access Journals (Sweden)

Jason Ivanoff

Full Text Available BACKGROUND: The speed and accuracy of decision-making have a well-known trading relationship: hasty decisions are more prone to errors while careful, accurate judgments take more time. Despite the pervasiveness of this speed-accuracy trade-off (SAT in decision-making, its neural basis is still unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using functional magnetic resonance imaging (fMRI we show that emphasizing the speed of a perceptual decision at the expense of its accuracy lowers the amount of evidence-related activity in lateral prefrontal cortex. Moreover, this speed-accuracy difference in lateral prefrontal cortex activity correlates with the speed-accuracy difference in the decision criterion metric of signal detection theory. We also show that the same instructions increase baseline activity in a dorso-medial cortical area involved in the internal generation of actions. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the SAT is neurally implemented by modulating not only the amount of externally-derived sensory evidence used to make a decision, but also the internal urge to make a response. We propose that these processes combine to control the temporal dynamics of the speed-accuracy trade-off in decision-making.

Mobility Performance in Slow- and High-Speed LTE Real Scenarios

DEFF Research Database (Denmark)

Gimenez, Lucas Chavarria; Cascino, Maria Carmela; Stefan, Maria

2016-01-01

Mobility performance and handover data interruption times in real scenarios are studied by means of field measurements in an operational LTE network. Both slow- and high-speed scenarios are analyzed by collecting results from two different areas: Aalborg downtown and the highway which encircles...... in the city center as cells on the same site often cover different non-crossing street canyons. Moreover, no handover failures are experienced in the measurements which confirms robust LTE mobility performance. The average interruption time, which is at least equal to the handover execution time, lays within...... the same city. Measurements reveal that the terminal is configured by the network with different handover parametrization depending on the serving cell, which indicates the use of mobility robustness optimization. Although the network is dominated by three sector sites, no intra-site handovers are observed...

Establishing Relationship between Process Parameters and Temperature during High Speed End Milling of Soda Lime Glass

Science.gov (United States)

Nasima Bagum, Mst.; Konneh, Mohamed; Yeakub Ali, Mohammad

2018-01-01

In glass machining crack free surface is required in biomedical and optical industry. Ductile mode machining allows materials removal from brittle materials in a ductile manner rather than by brittle fracture. Although end milling is a versatile process, it has not been applied frequently for machining soda lime glass. Soda lime glass is a strain rate and temperature sensitive material; especially around glass transition temperature Tg, ductility increased and strength decreased. Hence, it is envisaged that the generated temperature by high-speed end milling (HSEM) could be brought close to the glass transition temperature, which promote ductile machining. In this research, the objective is to investigate the effect of high speed machining parameters on generated temperature. The cutting parameters were optimized to generate temperature around glass transition temperature of soda lime using response surface methodology (RSM). Result showed that the most influencing process parameter is feed rate followed by spindle speed and depth of cut to generate temperature. Confirmation test showed that combination of spindle speed 30,173 rpm, feed rate 13.2 mm/min and depth of cut 37.68 µm generate 635°C, hence ductile chip removal with machined surface Ra 0.358 µm was possible to achieve.

3D-CT of the temporal bone area with high-speed processing

International Nuclear Information System (INIS)

Hattori, Taku

1994-01-01

Three-dimentional (3D)-CT was introduced to represent abnormal findings in the temporal bone area utilizing a SOMATOM DRH CT scanner with accessory 3D reconstruction software and an exclusive high-speed 3D processing system, VOXEL FLINGER. In a patient with eosinophilic granuloma, a defect in the squamous part of the temporal bone was demonstrated suggesting exposure of the dura mater during surgery. In a patient with a normal ear, well-developed mastoid cavity, a part of the handle and the head of the malleus, the incudomalleal joint, the short limb, body and a part of the long limb of the incus and the round window niche were demonstrated. In a case of chronic otitis media, poorly developed mastoid cavity and a possible defect of the tip of the long limb of the incus were demonstrated, in contrast to the patient with the normal ear. 3D-CT yields objective and solid images which are useful for diagnosis, treatment planning and explanation of the pathology to patients and their family. To obtain convincing 3D images, physicians themselves have to choose exact rotation angles. It is not adequate to reconstruct original CT data using a CT computer with accessory 3D software whose processing capability is not good enough for this purpose. The conclusion is as follows: 1) it is necessary and effective to transfer original CT data into the memory of the exclusive high-speed 3D processing system and 2) process the data by the voxel memory method to establish a clinically valuable 3D-CT imaging system. (author)

GWAS for executive function and processing speed suggests involvement of the CADM2 gene

NARCIS (Netherlands)

C.A. Ibrahim-Verbaas (Carla); J. Bressler; S. Debette (Stéphanie); M. Schuur (Maaike); A.V. Smith; J.C. Bis (Joshua); G. Davies (Gail); S. Trompet (Stella); J.A. Smith; A. Björnsson (Asgeir); L.B. Chibnik (Lori); Y. Liu; V. Vitart (Veronique); M. Kirin (Mirna); K. Petrovic (Katja); O. Polasek (Ozren); L. Zgaga (Lina); C. Fawns-Ritchie; P. Hoffmann (Per); J. Karjalainen (Juha); J. Lahti; D.J. Llewellyn; C.O. Schmidt (Carsten O.); R. Mather; V. Chouraki (Vincent); Q. Sun; S. Resnick (Susan); L.M. Rose (Lynda M.); C. Oldmeadow (Christopher); M. Stewart; B.H. Smith; V. Gudnason (Vilmundur); Q. Yang (Qiong); S.S. Mirza (Saira); J.W. Jukema; P.L. DeJager (Philip L.); T.B. Harris (Tamara); D.C. Liewald (David C.); N. Amin (Najaf); L.H. Coker (Laura); O. Stegle (Oliver); O.L. Lopez; R. Schmidt; A. Teumer (Alexander); I. Ford; N. Karbalai (Nazanin); J.T. Becker (James); M.K. Jonsdottir (Maria K.); R. Au; R.S.N. Fehrmann (Rudolf); S. Herms (Stefan); M.A. Nalls (Michael); W. Zhao; S.T. Turner; K. Yaffe; K. Lohman (Kurt); J.C. van Swieten (John); S.L.R. Kardia; D.S. Knopman (David); W.M. Meeks (William); G. Heiss (Gerardo); E.G. Holliday (Elizabeth); P.W. Schofield; T. Tanaka (Toshiko); D.J. Stott (David J.); J. Wang (Jing); P.M. Ridker (Paul); A.J. Gow; A. Pattie (Alison); J.M. Starr (John); L.J. Hocking; N.J. Armstrong (Nicola J.); S. McLachlan (Stela); L. Shulman (Lee); L.C. Pilling (Luke); G. Eiriksdottir (Gudny); R.J. Scott; N.A. Kochan (Nicole A.); A. Palotie; Y.-C. Hsieh; J.G. Eriksson (Johan G.); A.D. Penman (Alan); R.F. Gottesman (Rebecca); B.A. Oostra (Ben); L. Yu; A.L. DeStefano (Anita L.); A. Beiser; M. Garcia; J.I. Rotter; M.M. Nöthen; A. Hofman (Albert); P.E. Slagboom (Eline); R.G.J. Westendorp; B.M. Buckley (Brendan M.); P.A. Wolf; A.G. Uitterlinden (André); B.M. Psaty (Bruce); H.J. Grabe (Hans Jörgen); S. Bandinelli (Stefania); D.I. Chasman (Daniel); F. Grodstein (Francine); K. Räikkönen (Katri); J.-C. Lambert; D.J. Porteous (David J.); J.F. Price (Jackie F.); P.S. Sachdev (Perminder); L. Ferrucci (Luigi); J. Attia (John); I. Rudan (Igor); C. Hayward; A.F. Wright; J.F. Wilson (James F); S. Cichon (Sven); L. Franke (Lude); H. Schmidt; J. Ding (Jingzhong); A.J. de Craen (Anton); M. Fornage (Myriam); D.A. Bennett (David); I.J. Deary (Ian); M.A. Ikram (Arfan); L.J. Launer (Lenore); A.L. Fitzpatrick; S. Seshadri (Sudha); C.M. van Duijn (Cornelia); T.H. Mosley (Thomas H.)

2016-01-01

textabstractTo identify common variants contributing to normal variation in two specific domains of cognitive functioning, we conducted a genome-wide association study (GWAS) of executive functioning and information processing speed in non-demented older adults from the CHARGE (Cohorts for Heart and

Computer-Based Cognitive Programs for Improvement of Memory, Processing Speed and Executive Function during Age-Related Cognitive Decline: A Meta-Analysis.

Directory of Open Access Journals (Sweden)

Yan-kun Shao

Full Text Available Several studies have assessed the effects of computer-based cognitive programs (CCP in the management of age-related cognitive decline, but the role of CCP remains controversial. Therefore, this systematic review evaluated the evidence on the efficacy of CCP for age-related cognitive decline in healthy older adults.Six electronic databases (through October 2014 were searched. The risk of bias was assessed using the Cochrane Collaboration tool. The standardized mean difference (SMD and 95% confidence intervals (CI of a random-effects model were calculated. The heterogeneity was assessed using the Cochran Q statistic and quantified with the I2 index.Twelve studies were included in the current review and were considered as moderate to high methodological quality. The aggregated results indicate that CCP improves memory performance (SMD, 0.31; 95% CI 0.16 to 0.45; p < 0.0001 and processing speed (SMD, 0.50; 95% CI 0.14 to 0.87; p = 0.007 but not executive function (SMD, -0.12; 95% CI -0.33 to 0.09; p = 0.27. Furthermore, there were long-term gains in memory performance (SMD, 0.59; 95% CI 0.13 to 1.05; p = 0.01.CCP may be a valid complementary and alternative therapy for age-related cognitive decline, especially for memory performance and processing speed. However, more studies with longer follow-ups are warranted to confirm the current findings.

Young drivers' responses to anti-speeding advertisements: Comparison of self-report and objective measures of persuasive processing and outcomes.

Science.gov (United States)

Kaye, Sherrie-Anne; Lewis, Ioni; Algie, Jennifer; White, Melanie J

2016-05-18

Self-report measures are typically used to assess the effectiveness of road safety advertisements. However, psychophysiological measures of persuasive processing (i.e., skin conductance response [SCR]) and objective driving measures of persuasive outcomes (i.e., in-vehicle Global Positioning System [GPS] devices) may provide further insights into the effectiveness of these advertisements. This study aimed to explore the persuasive processing and outcomes of 2 anti-speeding advertisements by incorporating both self-report and objective measures of speeding behavior. In addition, this study aimed to compare the findings derived from these different measurement approaches. Young drivers (N = 20, M age = 21.01 years) viewed either a positive or negative emotion-based anti-speeding television advertisement. While viewing the advertisement, SCR activity was measured to assess ad-evoked arousal responses. The RoadScout GPS device was then installed in participants' vehicles for 1 week to measure on-road speed-related driving behavior. Self-report measures assessed persuasive processing (emotional and arousal responses) and actual driving behavior. There was general correspondence between the self-report measures of arousal and the SCR and between the self-report measure of actual driving behavior and the objective driving data (as assessed via the GPS devices). This study provides insights into how psychophysiological and GPS devices could be used as objective measures in conjunction with self-report measures to further understand the persuasive processes and outcomes of emotion-based anti-speeding advertisements.

Tuning of the PI Controller Parameters of a PMSG Wind Turbine to Improve Control Performance under Various Wind Speeds

Directory of Open Access Journals (Sweden)

Yun-Su Kim

2015-02-01

Full Text Available This paper presents a method to seek the PI controller parameters of a PMSG wind turbine to improve control performance. Since operating conditions vary with the wind speed, therefore the PI controller parameters should be determined as a function of the wind speed. Small-signal modeling of a PMSG WT is implemented to analyze the stability under various operating conditions and with eigenvalues obtained from the small-signal model of the PMSG WT, which are coordinated by adjusting the PI controller parameters. The parameters to be tuned are chosen by investigating participation factors of state variables, which simplifies the problem by reducing the number of parameters to be tuned. The process of adjusting these PI controller parameters is carried out using particle swarm optimization (PSO. To characterize the improvements in the control method due to the PSO method of tuning the PI controller parameters, the PMSG WT is modeled using the MATLAB/SimPowerSystems libraries with the obtained PI controller parameters.

The relations among body consciousness, somatic symptom report, and information processing speed in chronic fatigue syndrome.

NARCIS (Netherlands)

Werf, S.P. van der; Vree, B.P.W. de; Meer, J.W.M. van der; Bleijenberg, G.

2002-01-01

OBJECTIVE: The aim of this study was to assess the potential influence of body consciousness and levels of somatic symptom report upon information processing speed in patients with chronic fatigue syndrome (CFS). BACKGROUND: According to a model of a fixed information processing capacity, it was

Calibration of automatic performance measures - speed and volume data: volume 2, evaluation of the accuracy of approach volume counts and speeds collected by microwave sensors.

Science.gov (United States)

2016-05-01

This study evaluated the accuracy of approach volumes and free flow approach speeds collected by the Wavetronix : SmartSensor Advance sensor for the Signal Performance Metrics system of the Utah Department of Transportation (UDOT), : using the field ...

Mapping the developmental constraints on working memory span performance.

Science.gov (United States)

Bayliss, Donna M; Jarrold, Christopher; Baddeley, Alan D; Gunn, Deborah M; Leigh, Eleanor

2005-07-01

This study investigated the constraints underlying developmental improvements in complex working memory span performance among 120 children of between 6 and 10 years of age. Independent measures of processing efficiency, storage capacity, rehearsal speed, and basic speed of processing were assessed to determine their contribution to age-related variance in complex span. Results showed that developmental improvements in complex span were driven by 2 age-related but separable factors: 1 associated with general speed of processing and 1 associated with storage ability. In addition, there was an age-related contribution shared between working memory, processing speed, and storage ability that was important for higher level cognition. These results pose a challenge for models of complex span performance that emphasize the importance of processing speed alone.

Brain training game improves executive functions and processing speed in the elderly: a randomized controlled trial.

Science.gov (United States)

Nouchi, Rui; Taki, Yasuyuki; Takeuchi, Hikaru; Hashizume, Hiroshi; Akitsuki, Yuko; Shigemune, Yayoi; Sekiguchi, Atsushi; Kotozaki, Yuka; Tsukiura, Takashi; Yomogida, Yukihito; Kawashima, Ryuta

2012-01-01

The beneficial effects of brain training games are expected to transfer to other cognitive functions, but these beneficial effects are poorly understood. Here we investigate the impact of the brain training game (Brain Age) on cognitive functions in the elderly. Thirty-two elderly volunteers were recruited through an advertisement in the local newspaper and randomly assigned to either of two game groups (Brain Age, Tetris). This study was completed by 14 of the 16 members in the Brain Age group and 14 of the 16 members in the Tetris group. To maximize the benefit of the interventions, all participants were non-gamers who reported playing less than one hour of video games per week over the past 2 years. Participants in both the Brain Age and the Tetris groups played their game for about 15 minutes per day, at least 5 days per week, for 4 weeks. Each group played for a total of about 20 days. Measures of the cognitive functions were conducted before and after training. Measures of the cognitive functions fell into four categories (global cognitive status, executive functions, attention, and processing speed). Results showed that the effects of the brain training game were transferred to executive functions and to processing speed. However, the brain training game showed no transfer effect on any global cognitive status nor attention. Our results showed that playing Brain Age for 4 weeks could lead to improve cognitive functions (executive functions and processing speed) in the elderly. This result indicated that there is a possibility which the elderly could improve executive functions and processing speed in short term training. The results need replication in large samples. Long-term effects and relevance for every-day functioning remain uncertain as yet. UMIN Clinical Trial Registry 000002825.

Brain training game improves executive functions and processing speed in the elderly: a randomized controlled trial.

Directory of Open Access Journals (Sweden)

Rui Nouchi

Full Text Available The beneficial effects of brain training games are expected to transfer to other cognitive functions, but these beneficial effects are poorly understood. Here we investigate the impact of the brain training game (Brain Age on cognitive functions in the elderly.Thirty-two elderly volunteers were recruited through an advertisement in the local newspaper and randomly assigned to either of two game groups (Brain Age, Tetris. This study was completed by 14 of the 16 members in the Brain Age group and 14 of the 16 members in the Tetris group. To maximize the benefit of the interventions, all participants were non-gamers who reported playing less than one hour of video games per week over the past 2 years. Participants in both the Brain Age and the Tetris groups played their game for about 15 minutes per day, at least 5 days per week, for 4 weeks. Each group played for a total of about 20 days. Measures of the cognitive functions were conducted before and after training. Measures of the cognitive functions fell into four categories (global cognitive status, executive functions, attention, and processing speed. Results showed that the effects of the brain training game were transferred to executive functions and to processing speed. However, the brain training game showed no transfer effect on any global cognitive status nor attention.Our results showed that playing Brain Age for 4 weeks could lead to improve cognitive functions (executive functions and processing speed in the elderly. This result indicated that there is a possibility which the elderly could improve executive functions and processing speed in short term training. The results need replication in large samples. Long-term effects and relevance for every-day functioning remain uncertain as yet.UMIN Clinical Trial Registry 000002825.

A novel conductive-polymer-based integration process for high-performance flip-chip packages

Science.gov (United States)

Lohokare, Saurabh

Conductive polymers have recently attracted considerable attention for low-temperature fabrication of lead-free, reworkable, and flexible flip-chip interconnects. Using these materials, I demonstrate in this thesis a process that enables low-cost and high-resolution flip-chip interconnects using conventional micro-fabrication techniques. This fabrication process offers improved performance as compared to conventional flip-chip techniques, such as screen-printing, and allows for definition of interconnects with excellent surface uniformity and control over the bump profile. In order to demonstrate the utility and wide applicability of this process, several test implementations that serve as case studies were investigated. Specifically, novel InGaAsSb avalanche photodiodes (APDs), operating around lambda = 2m and targeted for free-space communication and biomedical spectroscopy applications, were fabricated and flip-chip-integrated to test the static electrical characteristics of the polymer bumps. Additionally, the dynamic electrical performance characteristics of the polymer bumps were studied by using AlGaAsSb/AlGaSb p-i-n photodetectors as a case study. The fabrication of these photodetectors, operating around lambda = 1.55mum and targeted for optical communication applications, was accomplished using a customized inductively coupled plasma (ICP) etch process that resulted in a low dark current and excellent speed (3dB bandwidth of 10GHz) and, responsivity (60% external quantum efficiency) characteristics. Furthermore, flip-chip integration was used to demonstrate a three-dimensional, point-to-point micro-optical interconnect, which was 2.33mm-long in a system 15.27mm3 in volume. Lastly, high-speed parallel optical interconnects were demonstrated using polymer-flip-chip-integrated 10GHz vertical-cavity surface-emitting laser (VCSEL) and DOEs. Such interconnects offer the ability to alleviate the communication bottleneck that is projected to occur in future, high-performance

Visual encoding impairment in patients with schizophrenia: contribution of reduced working memory span, decreased processing speed, and affective symptoms.

Science.gov (United States)

Brébion, Gildas; Stephan-Otto, Christian; Huerta-Ramos, Elena; Ochoa, Susana; Usall, Judith; Abellán-Vega, Helena; Roca, Mercedes; Haro, Josep Maria

2015-01-01

Previous research has revealed the contribution of decreased processing speed and reduced working memory span in verbal and visual memory impairment in patients with schizophrenia. The role of affective symptoms in verbal memory has also emerged in a few studies. The authors designed a picture recognition task to investigate the impact of these factors on visual encoding. Two types of pictures (black and white vs. colored) were presented under 2 different conditions of context encoding (either displayed at a specific location or in association with another visual stimulus). It was assumed that the process of encoding associated pictures was more effortful than that of encoding pictures that were presented alone. Working memory span and processing speed were assessed. In the patient group, working memory span was significantly associated with the recognition of the associated pictures but not significantly with that of the other pictures. Controlling for processing speed eliminated the patients' deficit in the recognition of the colored pictures and greatly reduced their deficit in the recognition of the black-and-white pictures. The recognition of the black-and-white pictures was inversely related to anxiety in men and to depression in women. Working memory span constrains the effortful visual encoding processes in patients, whereas processing speed decrement accounts for most of their visual encoding deficit. Affective symptoms also have an impact on visual encoding, albeit differently in men and women. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Effect of In-Vehicle Audio Warning System on Driver’s Speed Control Performance in Transition Zones from Rural Areas to Urban Areas

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Xuedong Yan

2016-06-01

Full Text Available Speeding is a major contributing factor to traffic crashes and frequently happens in areas where there is a mutation in speed limits, such as the transition zones that connect urban areas from rural areas. The purpose of this study is to investigate the effects of an in-vehicle audio warning system and lit speed limit sign on preventing drivers’ speeding behavior in transition zones. A high-fidelity driving simulator was used to establish a roadway network with the transition zone. A total of 41 participants were recruited for this experiment, and the driving speed performance data were collected from the simulator. The experimental results display that the implementation of the audio warning system could significantly reduce drivers’ operating speed before they entered the urban area, while the lit speed limit sign had a minimal effect on improving the drivers’ speed control performance. Without consideration of different types of speed limit signs, it is found that male drivers generally had a higher operating speed both upstream and in the transition zones and have a larger maximum deceleration for speed reduction than female drivers. Moreover, the drivers who had medium-level driving experience had the higher operating speed and were more likely to have speeding behaviors in the transition zones than those who had low-level and high-level driving experience in the transition zones.

Model-Scale Aerodynamic Performance Testing of Proposed Modifications to the NASA Langley Low Speed Aeroacoustic Wind Tunnel

Science.gov (United States)

Booth, Earl R., Jr.; Coston, Calvin W., Jr.

2005-01-01

Tests were performed on a 1/20th-scale model of the Low Speed Aeroacoustic Wind Tunnel to determine the performance effects of insertion of acoustic baffles in the tunnel inlet, replacement of the existing collector with a new collector design in the open jet test section, and addition of flow splitters to the acoustic baffle section downstream of the test section. As expected, the inlet baffles caused a reduction in facility performance. About half of the performance loss was recovered by addition the flow splitters to the downstream baffles. All collectors tested reduced facility performance. However, test chamber recirculation flow was reduced by the new collector designs and shielding of some of the microphones was reduced owing to the smaller size of the new collector. Overall performance loss in the facility is expected to be a 5 percent top flow speed reduction, but the facility will meet OSHA limits for external noise levels and recirculation in the test section will be reduced.

Cognitive Flexibility, Attention and Speed of Mental Processing in Opioid and Methamphetamine Addicts in Comparison with Non-Addicts

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Suzan Hekmat

2011-09-01

Full Text Available  Introduction: Many studies have revealed that drug addicted individuals exhibit impaired performance on executive function tests but a few studies have been conducted on executive functions of drug addicts in Iran. To contribute to this understanding, the present study was designed to assess some domains related to executive functions including cognitive flexibility, attention and speed of mental processing in a sample of drug addicts in comparison with a sample of non-drug addicts. Methods: 155 male addicts between 25 to 35 years of age were selected from outpatient addiction clinics in Karaj, Iran. This group consisted of 3 subgroups of opium (n=40, hydrochloride heroin (n=63, and methamphetamine (n=52 addicts. A control group was selected matching the drug addicts in gender, age, education and scio-economic status and included 130 healthy non-drug taking males. A battery of standardized executive function tests including the Color trail making test, Stroop color word test, and Symbol digit modalities test were administered. Data analysis was conducted by performing Co-variance (MANCOVA in SPSS.v.16.0. Results: The study findings indicated that the group of drug addicted subjects performed significantly worse compared with the controls on all executive measures. There were also significant differences among the 3 subgroups. The hydrochloride group had the worst performance compared the methamphetamine and opium groups respectively. Drug addicted subjects with longer duration of drug addiction were much worse on all measures in comparison with drug addicted subjects with shorter duration of drug addiction. Discussion: The study results confirmed that the functions of specific brain regions underlying cognitive flexibility, attention and speed of mental processing were significantly impaired in the group of drug addicted subjects. These impairments were also significantly related to type of drug used and duration of drug addiction that may

Cognitive Flexibility, Attention and Speed of Mental Processing in Opioid and Methamphetamine Addicts in Comparison with Non-Addicts

Directory of Open Access Journals (Sweden)

Suzan Hekmat

2011-09-01

Full Text Available Introduction: Many studies have revealed that drug addicted individuals exhibit impaired performance on executive function tests but a few studies have been conducted on executive functions of drug addicts in Iran. To contribute to this understanding, the present study was designed to assess some domains related to executive functions including cognitive flexibility, attention and speed of mental processing in a sample of drug addicts in comparison with a sample of non-drug addicts. Methods: 155 male addicts between 25 to 35 years of age were selected from outpatient addiction clinics in Karaj, Iran. This group consisted of 3 subgroups of opium (n=40, hydrochloride heroin (n=63, and methamphetamine (n=52 addicts. A control group was selected matching the drug addicts in gender, age, education and scio-economic status and included 130 healthy non-drug taking males. A battery of standardized executive function tests including the Color trail making test, Stroop color word test, and Symbol digit modalities test were administered. Data analysis was conducted by performing Co-variance (MANCOVA in SPSS.v.16.0. Results: The study findings indicated that the group of drug addicted subjects performed significantly worse compared with the controls on all executive measures. There were also significant differences among the 3 subgroups. The hydrochloride group had the worst performance compared the methamphetamine and opium groups respectively. Drug addicted subjects with longer duration of drug addiction were much worse on all measures in comparison with drug addicted subjects with shorter duration of drug addiction. Discussion: The study results confirmed that the functions of specific brain regions underlying cognitive flexibility, attention and speed of mental processing were significantly impaired in the group of drug addicted subjects. These impairments were also significantly related to type of drug used and duration of drug addiction that may

Effects of Age and Initial Risk Perception on Balloon Analogue Risk Task: The Mediating Role of Processing Speed and Need for Cognitive Closure

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Maciej eKoscielniak

2016-05-01

Full Text Available According to the dual-process theoretical perspective adopted in the presented research, the efficiency of deliberative processes in decision making declines with age, but experiential processes are relatively well-preserved. The age-related differences in deliberative and experiential processes in risky decision-making were examined in this research by applying the Balloon Analogue Risk Task (BART. We analyzed the influence of age on risk acceptance and decision-making performance in two age groups of female participants (younger adults, n = 81; older adults, n = 76, with additional experimental manipulation of initial risk perception. We predicted and confirmed that aging significantly worsens performance on the behavioral BART measures due to age-related decline in deliberative processes. Older participants were found to exhibit significantly higher risk aversion and lower BART performance, and the effect of age was mediated by cognitive (processing speed and motivational (need for cognitive closure mechanisms. Moreover, older adults adapt to the initial failure (vs. success similarly as younger adults due to preserved efficiency of experiential processes. These results suggest future directions for minimizing negative effects of aging in risky decision-making and indicate compensatory processes, which are preserved during aging.

A high speed dual-gain preamplifier system with multiple channels

International Nuclear Information System (INIS)

Zhao Lei; Liu Shubin; Xian Ze; An Qi

2008-01-01

In this paper, a multiple-channel high speed preamplifier module with dual-gain is presented, together with its design principle, test methods and performance parameter. By proper choice of the chips and careful circuit design, the preamplifier accomplishes a fine performance in high speed analog signal processing. The 3 dB bandwidth is above 440 MHz for gain factor of 2 and 280 MHz for gain factor of 8, with the leading edge time of less than 2 ns. The preamplifier module has been used in the research project of β-delayed neutron emission of radionuclides in neutron-rich region. (authors)

Performance Optimization Design for a High-Speed Weak FBG Interrogation System Based on DFB Laser

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Yiqiang Yao

2017-06-01

Full Text Available A performance optimization design for a high-speed fiber Bragg grating (FBG interrogation system based on a high-speed distributed feedback (DFB swept laser is proposed. A time-division-multiplexing sensor network with identical weak FBGs is constituted to realize high-capacity sensing. In order to further improve the multiplexing capacity, a waveform repairing algorithm is designed to extend the dynamic demodulation range of FBG sensors. It is based on the fact that the spectrum of an FBG keeps stable over a long period of time. Compared with the pre-collected spectra, the distorted spectra waveform are identified and repaired. Experimental results show that all the identical weak FBGs are distinguished and demodulated at the speed of 100 kHz with a linearity of above 0.99, and the range of dynamic demodulation is extended by 40%.

Performance Optimization Design for a High-Speed Weak FBG Interrogation System Based on DFB Laser.

Science.gov (United States)

Yao, Yiqiang; Li, Zhengying; Wang, Yiming; Liu, Siqi; Dai, Yutang; Gong, Jianmin; Wang, Lixin

2017-06-22

A performance optimization design for a high-speed fiber Bragg grating (FBG) interrogation system based on a high-speed distributed feedback (DFB) swept laser is proposed. A time-division-multiplexing sensor network with identical weak FBGs is constituted to realize high-capacity sensing. In order to further improve the multiplexing capacity, a waveform repairing algorithm is designed to extend the dynamic demodulation range of FBG sensors. It is based on the fact that the spectrum of an FBG keeps stable over a long period of time. Compared with the pre-collected spectra, the distorted spectra waveform are identified and repaired. Experimental results show that all the identical weak FBGs are distinguished and demodulated at the speed of 100 kHz with a linearity of above 0.99, and the range of dynamic demodulation is extended by 40%.

Episodic feeling-of-knowing accuracy and cued recall in the elderly: evidence for double dissociation involving executive functioning and processing speed.

Science.gov (United States)

Perrotin, Audrey; Isingrini, Michel; Souchay, Céline; Clarys, David; Taconnat, Laurence

2006-05-01

This research investigated adult age differences in a metamemory monitoring task-episodic feeling-of-knowing (FOK) and in an episodic memory task-cued recall. Executive functioning and processing speed were examined as mediators of these age differences. Young and elderly adults were administered an episodic FOK task, a cued recall task, executive tests and speed tests. Age-related decline was observed on all the measures. Correlation analyses revealed a pattern of double dissociation which indicates a specific relationship between executive score and FOK accuracy, and between speed score and cued recall. When executive functioning and processing speed were evaluated concurrently on FOK and cued recall variables, hierarchical regression analyses showed that executive score was a better mediator of age-related variance in FOK, and that speed score was the better mediator of age-related variance in cued recall.

Free-piston driver performance characterisation using experimental shock speeds through helium

Science.gov (United States)

Gildfind, D. E.; James, C. M.; Morgan, R. G.

2015-03-01

Tuned free-piston driver operation involves configuring the driver to produce a relatively steady blast of driver gas over the critical time scales of the experiment. For the purposes of flow condition development and parametric studies, it is useful to establish some average working values of the driver pressure and temperature for a given driver operating condition. However, in practise, these averaged values need to produce sufficiently accurate estimates of performance. In this study, two tuned driver conditions in the X2 expansion tube have been used to generate shock waves through a helium test gas. The measured shock speeds have then been used to calculate the effective driver gas pressure and temperature after diaphragm rupture. Since the driver gas is typically helium, or a mixture of helium and argon, and the test gas is also helium, ideal gas assumptions can be made without significant loss of accuracy. The technique is applicable to tuned free-piston drivers with a simple area change, as well as those using orifice plates. It is shown that this technique can be quickly used to establish average working driver gas properties which produce very good estimates of actual driven shock speed, across a wide range of operating conditions. The use of orifice plates to control piston dynamics at high driver gas sound speeds is also discussed in the paper, and a simple technique for calculating the restriction required to modify an established safe condition for use with lighter gases, such as pure helium, is presented.

The stability of AQT processing speed, ADAS-Cog and MMSE during acetylcholinesterase inhibitor treatment in Alzheimer's disease.

Science.gov (United States)

Wiig, E H; Annas, P; Basun, H; Andreasen, N; Lannfelt, L; Zetterberg, H; Blennow, K; Minthon, L

2010-03-01

To explore the longitudinal stability of measures of cognition during treatment with acetylcholinesterase inhibitors (AchEI) in patients with Alzheimer's disease (AD). Cognitive status was measured in a cohort of 60 patients at 6 months after initiation of treatment with AchEI (baseline) and after an additional 6 months of treatment (endpoint). A Quick Test of Cognitive Speed (AQT), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), and MMSE were administered concurrently. Correlations (rho) between age and AQT processing speed were non-significant, but were significant for ADAS-Cog and Mini Mental State Examination (MMSE). AQT and ADAS-Cog means did not differ significantly between baseline and endpoint. There was a small, significant reduction in MMSE point scores. Measures of stability (Spearman's rho) were moderate-to-high for all tests. Means for subgroups did not differ as a function of medication type. AQT processing speed, ADAS-Cog, and MMSE measures proved stable during the second 6 months of treatment with AChEI.

The effects of mild and severe traumatic brain injury on speed of information processing as measured by the computerized tests of information processing (CTIP).

Science.gov (United States)

Tombaugh, Tom N; Rees, Laura; Stormer, Peter; Harrison, Allyson G; Smith, Andra

2007-01-01

In spite of the fact that reaction time (RT) measures are sensitive to the effects of traumatic brain injury (TBI), few RT procedures have been developed for use in standard clinical evaluations. The computerized test of information processing (CTIP) [Tombaugh, T. N., & Rees, L. (2000). Manual for the computerized tests of information processing (CTIP). Ottawa, Ont.: Carleton University] was designed to measure the degree to which TBI decreases the speed at which information is processed. The CTIP consists of three computerized programs that progressively increase the amount of information that is processed. Results of the current study demonstrated that RT increased as the difficulty of the CTIP tests increased (known as the complexity effect), and as severity of injury increased (from mild to severe TBI). The current study also demonstrated the importance of selecting a non-biased measure of variability. Overall, findings suggest that the CTIP is an easy to administer and sensitive measure of information processing speed.

High-Speed Computation using FPGA for Excellent Performance of Direct Torque Control of Induction Machines

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Tole Sutikno

2016-03-01

Full Text Available The major problems in hysteresis-based DTC are high torque ripple and variable switching frequency. In order to minimize the torque ripple, high sampling time and fast digital realization should be applied. The high sampling and fast digital realization time can be achieved by utilizing high-speed processor where the operation of the discrete hysteresis regulator is becoming similar to the operation of analog-based comparator. This can be achieved by utilizing field programmable gate array (FPGA which can perform a sampling at a very high speed, compared to the fact that developing an ASIC chip is expensive and laborious.

Surface regions of illusory images are detected with a slower processing speed than those of luminance-defined images.

Science.gov (United States)

Mihaylova, Milena; Manahilov, Velitchko

2010-11-24

Research has shown that the processing time for discriminating illusory contours is longer than for real contours. We know, however, little whether the visual processes, associated with detecting regions of illusory surfaces, are also slower as those responsible for detecting luminance-defined images. Using a speed-accuracy trade-off (SAT) procedure, we measured accuracy as a function of processing time for detecting illusory Kanizsa-type and luminance-defined squares embedded in 2D static luminance noise. The data revealed that the illusory images were detected at slower processing speed than the real images, while the points in time, when accuracy departed from chance, were not significantly different for both stimuli. The classification images for detecting illusory and real squares showed that observers employed similar detection strategies using surface regions of the real and illusory squares. The lack of significant differences between the x-intercepts of the SAT functions for illusory and luminance-modulated stimuli suggests that the detection of surface regions of both images could be based on activation of a single mechanism (the dorsal magnocellular visual pathway). The slower speed for detecting illusory images as compared to luminance-defined images could be attributed to slower processes of filling-in of regions of illusory images within the dorsal pathway.

The Application of Virtex-II Pro FPGA in High-Speed Image Processing Technology of Robot Vision Sensor

International Nuclear Information System (INIS)

Ren, Y J; Zhu, J G; Yang, X Y; Ye, S H

2006-01-01

The Virtex-II Pro FPGA is applied to the vision sensor tracking system of IRB2400 robot. The hardware platform, which undertakes the task of improving SNR and compressing data, is constructed by using the high-speed image processing of FPGA. The lower level image-processing algorithm is realized by combining the FPGA frame and the embedded CPU. The velocity of image processing is accelerated due to the introduction of FPGA and CPU. The usage of the embedded CPU makes it easily to realize the logic design of interface. Some key techniques are presented in the text, such as read-write process, template matching, convolution, and some modules are simulated too. In the end, the compare among the modules using this design, using the PC computer and using the DSP, is carried out. Because the high-speed image processing system core is a chip of FPGA, the function of which can renew conveniently, therefore, to a degree, the measure system is intelligent

The Application of Virtex-II Pro FPGA in High-Speed Image Processing Technology of Robot Vision Sensor

Science.gov (United States)

Ren, Y. J.; Zhu, J. G.; Yang, X. Y.; Ye, S. H.

2006-10-01

The Virtex-II Pro FPGA is applied to the vision sensor tracking system of IRB2400 robot. The hardware platform, which undertakes the task of improving SNR and compressing data, is constructed by using the high-speed image processing of FPGA. The lower level image-processing algorithm is realized by combining the FPGA frame and the embedded CPU. The velocity of image processing is accelerated due to the introduction of FPGA and CPU. The usage of the embedded CPU makes it easily to realize the logic design of interface. Some key techniques are presented in the text, such as read-write process, template matching, convolution, and some modules are simulated too. In the end, the compare among the modules using this design, using the PC computer and using the DSP, is carried out. Because the high-speed image processing system core is a chip of FPGA, the function of which can renew conveniently, therefore, to a degree, the measure system is intelligent.

Genetic Variance in Processing Speed Drives Variation in Aging of Spatial and Memory Abilities

Science.gov (United States)

Finkel, Deborah; Reynolds, Chandra A.; McArdle, John J.; Hamagami, Fumiaki; Pedersen, Nancy L.

2009-01-01

Previous analyses have identified a genetic contribution to the correlation between declines with age in processing speed and higher cognitive abilities. The goal of the current analysis was to apply the biometric dual change score model to consider the possibility of temporal dynamics underlying the genetic covariance between aging trajectories…

British Standard method for determination of ISO speed and average gradient of direct-exposure medical and dental radiographic film/process combinations

International Nuclear Information System (INIS)

1983-01-01

Under the direction of the Cinematography and Photography Standards Committee, a British Standard method has been prepared for determining ISO speed and average gradient of direct-exposure medical and dental radiographic film/film-process combinations. The method determines the speed and gradient, i.e. contrast, of the X-ray films processed according to their manufacturer's recommendations. (U.K.)

Do Maximal Roller Skiing Speed and Double Poling Performance Predict Youth Cross-Country Skiing Performance?

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Roland Stöggl, Erich Müller, Thomas Stöggl

2017-09-01

Full Text Available The aims of the current study were to analyze whether specific roller skiing tests and cycle length are determinants of youth cross-country (XC skiing performance, and to evaluate sex specific differences by applying non-invasive diagnostics. Forty-nine young XC skiers (33 boys; 13.8 ± 0.6 yrs and 16 girls; 13.4 ± 0.9 yrs performed roller skiing tests consisting of both shorter (50 m and longer durations (575 m. Test results were correlated with on snow XC skiing performance (PXC based on 3 skating and 3 classical distance competitions (3 to 6 km. The main findings of the current study were: 1 Anthropometrics and maturity status were related to boys’, but not to girls’ PXC; 2 Significant moderate to acceptable correlations between girls’ and boys’ short duration maximal roller skiing speed (double poling, V2 skating, leg skating and PXC were found; 3 Boys’ PXC was best predicted by double poling test performance on flat and uphill, while girls’ performance was mainly predicted by uphill double poling test performance; 4 When controlling for maturity offset, boys’ PXC was still highly associated with the roller skiing tests. The use of simple non-invasive roller skiing tests for determination of PXC represents practicable support for ski clubs, schools or skiing federations in the guidance and evaluation of young talent.

Application of dragonfly algorithm for optimal performance analysis of process parameters in turn-mill operations- A case study

Science.gov (United States)

Vikram, K. Arun; Ratnam, Ch; Lakshmi, VVK; Kumar, A. Sunny; Ramakanth, RT

2018-02-01

Meta-heuristic multi-response optimization methods are widely in use to solve multi-objective problems to obtain Pareto optimal solutions during optimization. This work focuses on optimal multi-response evaluation of process parameters in generating responses like surface roughness (Ra), surface hardness (H) and tool vibration displacement amplitude (Vib) while performing operations like tangential and orthogonal turn-mill processes on A-axis Computer Numerical Control vertical milling center. Process parameters like tool speed, feed rate and depth of cut are considered as process parameters machined over brass material under dry condition with high speed steel end milling cutters using Taguchi design of experiments (DOE). Meta-heuristic like Dragonfly algorithm is used to optimize the multi-objectives like ‘Ra’, ‘H’ and ‘Vib’ to identify the optimal multi-response process parameters combination. Later, the results thus obtained from multi-objective dragonfly algorithm (MODA) are compared with another multi-response optimization technique Viz. Grey relational analysis (GRA).

Distributed Large Data-Object Environments: End-to-End Performance Analysis of High Speed Distributed Storage Systems in Wide Area ATM Networks

Science.gov (United States)

Johnston, William; Tierney, Brian; Lee, Jason; Hoo, Gary; Thompson, Mary

1996-01-01

We have developed and deployed a distributed-parallel storage system (DPSS) in several high speed asynchronous transfer mode (ATM) wide area networks (WAN) testbeds to support several different types of data-intensive applications. Architecturally, the DPSS is a network striped disk array, but is fairly unique in that its implementation allows applications complete freedom to determine optimal data layout, replication and/or coding redundancy strategy, security policy, and dynamic reconfiguration. In conjunction with the DPSS, we have developed a 'top-to-bottom, end-to-end' performance monitoring and analysis methodology that has allowed us to characterize all aspects of the DPSS operating in high speed ATM networks. In particular, we have run a variety of performance monitoring experiments involving the DPSS in the MAGIC testbed, which is a large scale, high speed, ATM network and we describe our experience using the monitoring methodology to identify and correct problems that limit the performance of high speed distributed applications. Finally, the DPSS is part of an overall architecture for using high speed, WAN's for enabling the routine, location independent use of large data-objects. Since this is part of the motivation for a distributed storage system, we describe this architecture.

Visual Speed of Processing and Publically Observable Feedback in Video-Game Players

OpenAIRE

Patten, James William

2016-01-01

Time spent playing action-oriented video-games has been proposed to improve the functioning of visual attention and perception in a number of areas. These benefits are not always consistently reported, however. It was hypothesized that an improvement to visual Speed of Processing (SOP) in action-oriented Video-Game Players (VGPs) underlies many of the benefits of action video-game play, and furthermore the expression of this improvement was modulated by a Hawthorne effect (individuals behavin...

Computer ray tracing speeds.

Science.gov (United States)

Robb, P; Pawlowski, B

1990-05-01

The results of measuring the ray trace speed and compilation speed of thirty-nine computers in fifty-seven configurations, ranging from personal computers to super computers, are described. A correlation of ray trace speed has been made with the LINPACK benchmark which allows the ray trace speed to be estimated using LINPACK performance data. The results indicate that the latest generation of workstations, using CPUs based on RISC (Reduced Instruction Set Computer) technology, are as fast or faster than mainframe computers in compute-bound situations.

Prediction of multi performance characteristics of wire EDM process using grey ANFIS

Science.gov (United States)

Kumanan, Somasundaram; Nair, Anish

2017-09-01

Super alloys are used to fabricate components in ultra-supercritical power plants. These hard to machine materials are processed using non-traditional machining methods like Wire cut electrical discharge machining and needs attention. This paper details about multi performance optimization of wire EDM process using Grey ANFIS. Experiments are designed to establish the performance characteristics of wire EDM such as surface roughness, material removal rate, wire wear rate and geometric tolerances. The control parameters are pulse on time, pulse off time, current, voltage, flushing pressure, wire tension, table feed and wire speed. Grey relational analysis is employed to optimise the multi objectives. Analysis of variance of the grey grades is used to identify the critical parameters. A regression model is developed and used to generate datasets for the training of proposed adaptive neuro fuzzy inference system. The developed prediction model is tested for its prediction ability.

Associations between physical performance and executive function in older adults with mild cognitive impairment: gait speed and the timed "up & go" test.

Science.gov (United States)

McGough, Ellen L; Kelly, Valerie E; Logsdon, Rebecca G; McCurry, Susan M; Cochrane, Barbara B; Engel, Joyce M; Teri, Linda

2011-08-01

Older adults with amnestic mild cognitive impairment (aMCI) are at higher risk for developing Alzheimer disease. Physical performance decline on gait and mobility tasks in conjunction with executive dysfunction has implications for accelerated functional decline, disability, and institutionalization in sedentary older adults with aMCI. The purpose of this study was to examine whether performance on 2 tests commonly used by physical therapists (usual gait speed and Timed "Up & Go" Test [TUG]) are associated with performance on 2 neuropsychological tests of executive function (Trail Making Test, part B [TMT-B], and Stroop-Interference, calculated from the Stroop Word Color Test) in sedentary older adults with aMCI. The study was a cross-sectional analysis of 201 sedentary older adults with memory impairment participating in a longitudinal intervention study of cognitive function, aging, exercise, and health promotion. Physical performance speed on gait and mobility tasks was measured via usual gait speed and the TUG (at fast pace). Executive function was measured with the TMT-B and Stroop-Interference measures. Applying multiple linear regression, usual gait speed was associated with executive function on both the TMT-B (β=-0.215, P=.003) and Stroop-Interference (β=-0.195, P=.01) measures, indicating that slower usual gait speed was associated with lower executive function performance. Timed "Up & Go" Test scores (in logarithmic transformation) also were associated with executive function on both the TMT-B (β=0.256, Pfunction performance. All associations remained statistically significant after adjusting for age, sex, depressive symptoms, medical comorbidity, and body mass index. The cross-sectional nature of this study does not allow for inferences of causation. Physical performance speed was associated with executive function after adjusting for age, sex, and age-related factors in sedentary older adults with aMCI. Further research is needed to determine

FRAS1-related extracellular matrix 3 (FREM3 single-nucleotide polymorphism effects on gene expression, amygdala reactivity and perceptual processing speed

Directory of Open Access Journals (Sweden)

Yuliya eNikolova

2015-09-01

Full Text Available The A allele of the Fras1-related extracellular matrix protein 3 (FREM3 rs7676614 single nucleotide polymorphism (SNP was linked to major depressive disorder (MDD in an early genome-wide association study (GWAS, and to symptoms of psychomotor retardation in a follow-up investigation. In line with significant overlap between age- and depression-related molecular pathways, parallel work has shown that FREM3 expression in postmortem human brain decreases with age. Here we probe the effect of rs7676614 on amygdala reactivity and perceptual processing speed, both of which are altered in depression and aging. Amygdala reactivity was assessed using a face-matching BOLD fMRI paradigm in 365 Caucasian participants in the Duke Neurogenetics Study (192 women, mean age 19.7±1.2. Perceptual processing speed was indexed by reaction times in the same task and the Trails Making Test (TMT. The effect of rs7676614 on FREM3 mRNA brain expression levels was probed in a postmortem cohort of 169 Caucasian individuals (44 women, mean age 50.8±14.9. The A allele of rs7676614 was associated with blunted amygdala reactivity to faces, slower reaction times in the face-matching condition (p<0.04, as well as marginally slower performance on TMT Part B (p=0.056. In the postmortem cohort, the T allele of rs6537170 (proxy for the rs7676614 A allele, was associated with trend-level reductions in gene expression in Brodmann areas 11 and 47 (p=0.066, reminiscent of patterns characteristic of older age. The low-expressing allele of another FREM3 SNP (rs1391187 was similarly associated with reduced amygdala reactivity and slower TMT Part B speed, in addition to reduced BA47 activity and Extraversion (p<0.05. Together, these results suggest common genetic variation associated with reduced FREM3 expression may confer risk for a subtype of depression characterized by reduced reactivity to environmental stimuli and slower perceptual processing speed, possibly suggestive of

Myelin Breakdown Mediates Age-Related Slowing in Cognitive Processing Speed in Healthy Elderly Men

Science.gov (United States)

Lu, Po H.; Lee, Grace J.; Tishler, Todd A.; Meghpara, Michael; Thompson, Paul M.; Bartzokis, George

2013-01-01

Background: To assess the hypothesis that in a sample of very healthy elderly men selected to minimize risk for Alzheimer's disease (AD) and cerebrovascular disease, myelin breakdown in late-myelinating regions mediates age-related slowing in cognitive processing speed (CPS). Materials and methods: The prefrontal lobe white matter and the genu of…

Effects of Cycling vs. Running Training on Endurance Performance in Preparation for Inline Speed Skating.

Science.gov (United States)

Stangier, Carolin; Abel, Thomas; Hesse, Clemens; Claen, Stephanie; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

2016-06-01

Winter weather conditions restrict regular sport-specific endurance training in inline speed skating. As a result, this study was designed to compare the effects of cycling and running training programs on inline speed skaters' endurance performance. Sixteen (8 men, 8 women) high-level athletes (mean ± SD 24 ± 8 years) were randomly assigned to 1 of 2 groups (running and cycling). Both groups trained twice a week for 8 weeks, one group on a treadmill and the other on a cycle ergometer. Training intensity and duration was individually calculated (maximal fat oxidation: ∼52% of V[Combining Dot Above]O2peak: 500 kcal per session). Before and after the training intervention, all athletes performed an incremental specific (inline speed skating) and 1 nonspecific (cycling or running) step test according to the group affiliation. In addition to blood lactate concentration, oxygen uptake (V[Combining Dot Above]O2), ventilatory equivalent (VE/V[Combining Dot Above]O2), respiratory exchange ratio (RER), and heart rate were measured. The specific posttest revealed significantly increased absolute V[Combining Dot Above]O2peak values (2.9 ± 0.4, 3.4 ± 0.7, p = 0.01) and submaximal V[Combining Dot Above]O2 values (p ≤ 0.01). VE/V[Combining Dot Above]O2 and RER significantly decreased at maximal (46.6 ± 6.6, 38.5 ± 3.4, p = 0.005; 1.1 ± 0.03, 1.0 ± 0.04, p = 0.001) and submaximal intensities (p ≤ 0.04). None of the analysis revealed a significant group effect (p ≥ 0.15). The results indicate that both cycling vs. running exercise at ∼52% of V[Combining Dot Above]O2peak had a positive effect on the athletes' endurance performance. The increased submaximal V[Combining Dot Above]O2 values indicate a reduction in athletes' inline speed skating technique. Therefore, athletes would benefit from a focus on technique training in the subsequent period.

Conservation Abilities, Visuospatial Skills, and Numerosity Processing Speed: Association With Math Achievement and Math Difficulties in Elementary School Children.

Science.gov (United States)

Lambert, Katharina; Spinath, Birgit

The aim of the present study was to investigate the associations between elementary school children's mathematical achievement and their conservation abilities, visuospatial skills, and numerosity processing speed. We also assessed differences in these abilities between children with different types of learning problems. In Study 1 ( N = 229), we investigated second to fourth graders and in Study 2 ( N = 120), third and fourth graders. Analyses revealed significant contributions of numerosity processing speed and visuospatial skills to math achievement beyond IQ. Conservation abilities were predictive in Study 1 only. Children with math difficulties showed lower visuospatial skills and conservation abilities than children with typical achievement levels and children with reading and/or spelling difficulties, whereas children with combined difficulties explicitly showed low conservation abilities. These findings provide further evidence for the relations between children's math skills and their visuospatial skills, conservation abilities, and processing speed and contribute to the understanding of deficits that are specific to mathematical difficulties.

A double-blind, placebo-controlled study on the effects of lutein and zeaxanthin on neural processing speed and efficiency.

Directory of Open Access Journals (Sweden)

Emily R Bovier

Full Text Available Lutein and zeaxanthin are major carotenoids in the eye but are also found in post-receptoral visual pathways. It has been hypothesized that these pigments influence the processing of visual signals within and post-retina, and that increasing lutein and zeaxanthin levels within the visual system will lead to increased visual processing speeds. To test this, we measured macular pigment density (as a biomarker of lutein and zeaxanthin levels in brain, critical flicker fusion (CFF thresholds, and visual motor reaction time in young healthy subjects (n = 92. Changes in these outcome variables were also assessed after four months of supplementation with either placebo (n = 10, zeaxanthin only (20 mg/day; n = 29 or a mixed formulation containing 26 mg/day zeaxanthin, 8 mg/day lutein, and 190 mg/day mixed omega-3 fatty acids (n = 25. Significant correlations were found between retinal lutein and zeaxanthin (macular pigment and CFF thresholds (p<0.01 and visual motor performance (overall p<0.01. Supplementation with zeaxanthin and the mixed formulation (considered together produced significant (p<0.01 increases in CFF thresholds (∼12% and visual motor reaction time (∼10% compared to placebo. In general, increasing macular pigment density through supplementation (average increase of about 0.09 log units resulted in significant improvements in visual processing speed, even when testing young, healthy individuals who tend to be at peak efficiency.

Optimum Design of High Speed Prop-Rotors

Science.gov (United States)

Chattopadhyay, Aditi

1992-01-01

The objective of this research is to develop optimization procedures to provide design trends in high speed prop-rotors. The necessary disciplinary couplings are all considered within a closed loop optimization process. The procedures involve the consideration of blade aeroelastic, aerodynamic performance, structural and dynamic design requirements. Further, since the design involves consideration of several different objectives, multiobjective function formulation techniques are developed.

In-process, non-destructive multimodal dynamic testing of high-speed composite rotors

Science.gov (United States)

Kuschmierz, Robert; Filippatos, Angelos; Langkamp, Albert; Hufenbach, Werner; Czarske, Jürgern W.; Fischer, Andreas

2014-03-01

Fibre reinforced plastic (FRP) rotors are lightweight and offer great perspectives in high-speed applications such as turbo machinery. Currently, novel rotor structures and materials are investigated for the purpose of increasing machine efficiency, lifetime and loading limits. Due to complex rotor structures, high anisotropy and non-linear behavior of FRP under dynamic loads, an in-process measurement system is necessary to monitor and to investigate the evolution of damages under real operation conditions. A non-invasive, optical laser Doppler distance sensor measurement system is applied to determine the biaxial deformation of a bladed FRP rotor with micron uncertainty as well as the tangential blade vibrations at surface speeds above 300 m/s. The laser Doppler distance sensor is applicable under vacuum conditions. Measurements at varying loading conditions are used to determine elastic and plastic deformations. Furthermore they allow to determine hysteresis, fatigue, Eigenfrequency shifts and loading limits. The deformation measurements show a highly anisotropic and nonlinear behavior and offer a deeper understanding of the damage evolution in FRP rotors. The experimental results are used to validate and to calibrate a simulation model of the deformation. The simulation combines finite element analysis and a damage mechanics model. The combination of simulation and measurement system enables the monitoring and prediction of damage evolutions of FRP rotors in process.

High speed PVD thermal barrier coatings

Energy Technology Data Exchange (ETDEWEB)

Beele, W. [Sulzer Metco Coatings BV (Netherlands); Eschendorff, G. [Sulzer Metco Coatings BV (Netherlands); Eldim BV (Netherlands)

2006-07-15

The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

High speed PVD thermal barrier coatings

International Nuclear Information System (INIS)

Beele, W.; Eschendorff, G.

2006-01-01

The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Are we aware of the speed of erosion processes - an example from Slovene Istria

Directory of Open Access Journals (Sweden)

Matija Zorn

2007-12-01

Full Text Available Measurements of erosion and denudation processes in Dragonja river basin are presented. Measured were interrill erosion on three different land uses, rockwall retreat on steep flysch slopes, movements of debris in erosion gully and chemical denudation. Measurements took place between February 2005 and May 2006. The purpose of the article is to draw attention to the speed of some geomorphic processes. Due to this, we should lay more stress upon their role in morphogenesis of the landscape.

Thermal effects on human performance in office environment measured by integrating task speed and accuracy

DEFF Research Database (Denmark)

Lan, Li; Wargocki, Pawel; Lian, Zhiwei

2014-01-01

We have proposed a method in which the speed and accuracy can be integrated into one metric of human performance. This was achieved by designing a performance task in which the subjects receive feedback on their performance by informing them whether they have committed errors, and if did, they can......, 12 subjects performed tasks under two thermal conditions (neutral & warm) repeatedly. The tasks were presented with and without feedback on errors committed, as outlined above. The results indicate that there was a greater decrease in task performance due to thermal discomfort when feedback was given......, compared to the performance of tasks presented without feedback....

FUTSAL MATCH-RELATED FATIGUE AFFECTS RUNNING PERFORMANCE AND NEUROMUSCULAR PARAMETERS BUT NOT FINISHING KICK SPEED OR ACCURACY

Directory of Open Access Journals (Sweden)

Fabio Milioni

2016-11-01

Full Text Available Purpose: The aim of the present study was to investigate the influence of futsal match-related fatigue on running performance, neuromuscular variables, and finishing kick speed and accuracy. Methods: Ten professional futsal players participated in the study (age: 22.2±2.5 years; and initially performed an incremental protocol to determine maximum oxygen uptake (VO2max : 50.6±4.9 mL.kg-1.min-1. Next, simulated games were performed, in four periods of 10 min during which heart rate and blood lactate concentration were monitored. The entire games were video recorded for subsequent automatic tracking. Before and immediately after the simulated game, neuromuscular function was measured by maximal isometric force of knee extension, voluntary activation using twitch interpolation technique, and electromyographic activity. Before, at half time, and immediately after the simulated game, the athletes also performed a set of finishing kicks for ball speed and accuracy measurements. Results: Total distance covered (1st half: 1986.6±74.4 m; 2nd half: 1856.0±129.7 m – P=0.00 and distance covered per minute (1st half: 103.2±4.4 m.min-1; 2nd half: 96.4±7.5 m.min-1 – P=0.00 demonstrated significant declines during the simulated game, as well as maximal isometric force of knee extension (Before: 840.2±66.2 N; After: 751.6±114.3 N – P=0.04 and voluntary activation (Before: 85.9±7.5%; After: 74.1±12.3% – P=0.04, however ball speed and accuracy during the finishing kicks were not significantly affected.Conclusion: Therefore, we conclude that despite the decline in running performance and neuromuscular variables presenting an important manifestation of central fatigue, this condition apparently does not affect the speed and accuracy of finishing kicks.

A study on the performance and internal flow characteristics of a very low specific speed centrifugal pump

International Nuclear Information System (INIS)

Choi, Young Do; Kurokawa, Junichi; Lee, Young Ho

2005-01-01

In the very low specific speed range (n s < 0.25, non-dimensional), the efficiency of centrifugal pump designed by a conventional method is very low in common. Therefore, positive-displacement pumps have long been used widely. Recently, since the centrifugal pumps are becoming higher in rotational speed and smaller in size, there experts to develop a new centrifugal pump with a high performance to replace the positive-displacement pumps. The purpose of this study is to investigate the internal flow characteristics of a very low specific speed centrifugal pump and to examine the effect of internal flow pattern on pump performance. The results show that the theoretical head definition of semi-open impeller should be revised by the consideration of high slip factor in the semi-open impeller, and the leakage flow through the tip clearance results in a large effect on the impeller internal flow. Strong reverse flow at the outlet of semi-open impeller reduces the absolute tangential velocity considerably, and the decreased absolute tangential velocity increases the slip factor with the reduction of theoretical head

Ultra-high-speed Optical Signal Processing using Silicon Photonics

DEFF Research Database (Denmark)

Oxenløwe, Leif Katsuo; Ji, Hua; Jensen, Asger Sellerup

with a photonic layer on top to interconnect them. For such systems, silicon is an attractive candidate enabling both electronic and photonic control. For some network scenarios, it may be beneficial to use optical on-chip packet switching, and for high data-density environments one may take advantage...... of the ultra-fast nonlinear response of silicon photonic waveguides. These chips offer ultra-broadband wavelength operation, ultra-high timing resolution and ultra-fast response, and when used appropriately offer energy-efficient switching. In this presentation we review some all-optical functionalities based...... on silicon photonics. In particular we use nano-engineered silicon waveguides (nanowires) [1] enabling efficient phasematched four-wave mixing (FWM), cross-phase modulation (XPM) or self-phase modulation (SPM) for ultra-high-speed optical signal processing of ultra-high bit rate serial data signals. We show...

Critical speed as a predictor of aerobic performance in children

Directory of Open Access Journals (Sweden)

Wagner de Campos

2007-03-01

Full Text Available To compare times achieved in a 1,600m rural road run with the times predicted from critical speed, in additionto verify any association between critical speed and VO2max with the aerobic performance (1,600m time of children. The sample consisted of 25 boys and 39 girls, aged 9 to 11 years. Their critical speeds were determined using the work versus time model, performed in the 200m and 800m maximum runs. The value of VO2max was measured using a 20-meter shuttlerun test. Endurance performance was determinate from the time obtained in a rural 1,600m road run. Statistical proceduresused were descriptive analyses, Student’s t test and Pearson’s moment correlation, with signifi cance level set at p RESUMO O estudo teve como objetivo comparar o tempo obtido na prova de 1.600m com o tempo predito pela velocidade crítica, bem como verifi car a associação da velocidade crítica e da potência aeróbia (VO2máx com o desempenho aeróbio (tempo 1.600m em crianças. A amostra foi composta de 25 meninos e 39 meninas, com faixa etária entre 9 a 11 anos, classifi cadas nos estágios de maturação sexual 1 e 2 de Tanner. A velocidade crítica foi obtida pelo modelo de avaliação trabalho versus tempo, na realização de dois tiros máximos de 200m e 800m. O VO2máx foi obtido através do teste de vai-vem de 20m. O desempenho aeróbio foi obtido através do tempo de percurso em uma prova rústica de 1.600m. Utilizou-se a estatística descritiva, teste “t” student e a correlação de Pearson, adotando p<0,05. Em ambos os grupos, odesempenho obtido na prova de 1.600m foi significativamente menor que o desempenho predito pela velocidade crítica (masculino: 8,43 ± 0,78 min versus 10,16 ± 1,37 min; feminino: 9,09 ± 0,75 min versus 10,30 ± 1,09 min (p= 0,0001.Observaram-se correlações inversamente significativas entre a velocidade crítica e o desempenho aeróbio nos grupos masculino e feminino (r= -0,52 e r= -0,70, respectivamente, e entre o VO2m

Unstructured Grid Euler Method Assessment for Aerodynamics Performance Prediction of the Complete TCA Configuration at Supersonic Cruise Speed

Science.gov (United States)

Ghaffari, Farhad

1999-01-01

Unstructured grid Euler computations, performed at supersonic cruise speed, are presented for a proposed high speed civil transport configuration, designated as the Technology Concept Airplane (TCA) within the High Speed Research (HSR) Program. The numerical results are obtained for the complete TCA cruise configuration which includes the wing, fuselage, empennage, diverters, and flow through nacelles at Mach 2.4 for a range of angles-of-attack and sideslip. The computed surface and off-surface flow characteristics are analyzed and the pressure coefficient contours on the wing lower surface are shown to correlate reasonably well with the available pressure sensitive paint results, particularly, for the complex shock wave structures around the nacelles. The predicted longitudinal and lateral/directional performance characteristics are shown to correlate very well with the measured data across the examined range of angles-of-attack and sideslip. The results from the present effort have been documented into a NASA Controlled-Distribution report which is being presently reviewed for publication.

Short term performance and effect of speed humps on pavement condition of Alexandria Governorate roads

Directory of Open Access Journals (Sweden)

Wael Bekheet

2014-12-01

Some performance trends were observed and found to be statistically significant, including superior short-term performance of projects with good or average construction QC records when compared to poor construction QC records. Raveling was the most widely observed distress, while load-related distresses were not common. The analysis also showed that the presence of improper speed humps significantly affected the pavement condition, reducing the PCI of the pavement sections by up to 19 PCI points.

Dip-Coating Process Engineering and Performance Optimization for Three-State Electrochromic Devices

Science.gov (United States)

Wu, Lu; Yang, Dejiang; Fei, Lixun; Huang, Yue; Wu, Fang; Sun, Yiling; Shi, Jiayuan; Xiang, Yong

2017-06-01

Titanium dioxide (TiO2) nanoparticles were modified onto fluorine-doped tin oxide (FTO) via dip-coating technique with different nanoparticle sizes, lifting speeds, precursor concentrations, and dipping numbers. Electrodeposition-based electrochromic device with reversible three-state optical transformation (transparent, mirror, and black) was fabricated subsequently by sandwiching a suitable amount of gel electrolyte between modified FTO electrode and flat FTO electrode. Correlation between dip-coating process engineering, morphological features of TiO2 thin films, i.e., thickness and roughness, as well as performance of electrochromic devices, i.e., optical contrast, switching time, and cycling stability, were investigated. The modified device exhibits high optical contrast of 57%, the short coloration/bleaching switching time of 6 and 20 s, and excellent cycling stability after 1500 cycles of only 27% decrement rate by adjusting dip-coating processes engineering. The results in this study will provide valuable guidance for rational design of the electrochromic device with satisfactory performance.

Performance of MPI parallel processing implemented by MCNP5/ MCNPX for criticality benchmark problems

International Nuclear Information System (INIS)

Mark Dennis Usang; Mohd Hairie Rabir; Mohd Amin Sharifuldin Salleh; Mohamad Puad Abu

2012-01-01

MPI parallelism are implemented on a SUN Workstation for running MCNPX and on the High Performance Computing Facility (HPC) for running MCNP5. 23 input less obtained from MCNP Criticality Validation Suite are utilized for the purpose of evaluating the amount of speed up achievable by using the parallel capabilities of MPI. More importantly, we will study the economics of using more processors and the type of problem where the performance gain are obvious. This is important to enable better practices of resource sharing especially for the HPC facilities processing time. Future endeavours in this direction might even reveal clues for best MCNP5/ MCNPX coding practices for optimum performance of MPI parallelisms. (author)

a Variant of Lsd-Slam Capable of Processing High-Speed Low-Framerate Monocular Datasets

Science.gov (United States)

Schmid, S.; Fritsch, D.

2017-11-01

We develop a new variant of LSD-SLAM, called C-LSD-SLAM, which is capable of performing monocular tracking and mapping in high-speed low-framerate situations such as those of the KITTI datasets. The methods used here are robust against the influence of erronously triangulated points near the epipolar direction, which otherwise causes tracking divergence.

Speed-accuracy tradeoff in decision-making performance among pathological gamblers.

Science.gov (United States)

Kertzman, Semion; Vainder, Michael; Vishne, Tali; Aizer, Anat; Kotler, Moshe; Dannon, Pinhas N

2010-01-01

Pathological gambling is classified as an impulse control disorder in the DSM-IV-TR; however, few studies have investigated the relationship between gambling behavior and impulsive decision-making in time-non-limited situations. The subjects performed the Matching Familiar Figures Test (MFFT). The MFFT investigated the reflection-impulsivity dimension in pathological gamblers (n = 82) and demographically matched healthy subjects (n = 82). Our study demonstrated that pathological gamblers had a significantly higher rate of errors than healthy controls (p = 0.01) but were not different in terms of response time (p = 0.49). We found a similar power of correlation between the number of errors and response time in both pathological gamblers and controls. We may conclude that impaired performance of our pathological gamblers as compared to controls in a situation without time limit pressure cannot be explained by a trade-off of greater speed at the cost of less accuracy. The results of our study showed that pathological gamblers tend to make more errors but do not exhibit quicker responses as compared to the control group. Diminished MFFT performance in pathological gamblers as compared to controls supports findings of previous studies which show that pathological gamblers have impaired decision-making. Further controlled studies with a larger sample size which examine MFFT performance in pathological gamblers are necessary to confirm our results. Copyright 2009 S. Karger AG, Basel.

Real Time Speed Measure while Automobile Braking on Soft Sensing Technique

Energy Technology Data Exchange (ETDEWEB)

Zhu, W B; Li, D S; Lu, Y [China Jiliang University, Hangzhou, Zhejiang province, 310018 (China)

2006-10-15

Because the braking performance of automobile has close relationship to traffic safety, it is important to detect that. Focusing on the problem that the real time speed is difficult to obtain in detection process, soft sensing technique is introduced in this paper. According to analyzing the relationship of the dynamics equation of a moving automobile, a module of real time speed of braking is set up. By using imitation method with experiment data to get the pressure function of cylinder and analyzing the relationship between the trigging moment of a wheel and the pressure function of brake cylinder, the real time speed is confirmed in good precision. The maximal measurement error of real time speed is 8.7% and the precision can satisfy engineering request.

Real Time Speed Measure while Automobile Braking on Soft Sensing Technique

International Nuclear Information System (INIS)

Zhu, W B; Li, D S; Lu, Y

2006-01-01

Because the braking performance of automobile has close relationship to traffic safety, it is important to detect that. Focusing on the problem that the real time speed is difficult to obtain in detection process, soft sensing technique is introduced in this paper. According to analyzing the relationship of the dynamics equation of a moving automobile, a module of real time speed of braking is set up. By using imitation method with experiment data to get the pressure function of cylinder and analyzing the relationship between the trigging moment of a wheel and the pressure function of brake cylinder, the real time speed is confirmed in good precision. The maximal measurement error of real time speed is 8.7% and the precision can satisfy engineering request

Investigating international new product diffusion speed: A semiparametric approach

KAUST Repository

Hartman, Brian M.

2012-06-01

Global marketing managers are interested in understanding the speed of the new product diffusion process and how the speed has changed in our ever more technologically advanced and global marketplace. Understanding the process allows firms to forecast the expected rate of return on their new products and develop effective marketing strategies. The most recent major study on this topic [Marketing Science 21 (2002) 97-114] investigated new product diffusions in the United States.We expand upon that study in three important ways. (1) Van den Bulte notes that a similar study is needed in the international context, especially in developing countries. Our study covers four new product diffusions across 31 developed and developing nations from 1980-2004. Our sample accounts for about 80% of the global economic output and 60% of the global population, allowing us to examine more general phenomena. (2) His model contains the implicit assumption that the diffusion speed parameter is constant throughout the diffusion life cycle of a product. Recognizing the likely effects on the speed parameter of recent changes in the marketplace, we model the parameter as a semiparametric function, allowing it the flexibility to change over time. (3) We perform a variable selection to determine that the number of internet users and the consumer price index are strongly associated with the speed of diffusion. © Institute of Mathematical Statistics, 2012.

Performance analysis of a new positron camera geometry for high speed, fine particle tracking

Science.gov (United States)

Sovechles, J. M.; Boucher, D.; Pax, R.; Leadbeater, T.; Sasmito, A. P.; Waters, K. E.

2017-09-01

A new positron camera arrangement was assembled using 16 ECAT951 modular detector blocks. A closely packed, cross pattern arrangement was selected to produce a highly sensitive cylindrical region for tracking particles with low activities and high speeds. To determine the capabilities of this system a comprehensive analysis of the tracking performance was conducted to determine the 3D location error and location frequency as a function of tracer activity and speed. The 3D error was found to range from 0.54 mm for a stationary particle, consistent for all tracer activities, up to 4.33 mm for a tracer with an activity of 3 MBq and a speed of 4 m · s-1. For lower activity tracers (mineral particles inside a two-inch hydrocyclone and a 142 mm diameter flotation cell. A detailed trajectory, inside the hydrocyclone, of a  -212  +  106 µm (10-1 MBq) quartz particle displayed the expected spiralling motion towards the apex. This was the first time a mineral particle of this size had been successfully traced within a hydrocyclone, however more work is required to develop detailed velocity fields.

Parallel Algorithm for GPU Processing; for use in High Speed Machine Vision Sensing of Cotton Lint Trash

Directory of Open Access Journals (Sweden)

Mathew G. Pelletier

2008-02-01

unit “CPU”, wasgained. The new parallel algorithm operating on the GPU was able to process a 1024x1024image in less than 17ms. At this improved speed, the image processing system’s performance should now be sufficient to provide a system that would be capable of realtimefeed-back control that is in tight cooperation with the cleaning equipment.

The effects of passive leg press training on jumping performance, speed, and muscle power.

Science.gov (United States)

Liu, Chiang; Chen, Chuan-Shou; Ho, Wei-Hua; Füle, Róbert János; Chung, Pao-Hung; Shiang, Tzyy-Yuang

2013-06-01

Passive leg press (PLP) training was developed based on the concepts of the stretch-shortening cycle (SSC) and the benefits of high muscle contraction velocity. Passive leg press training enables lower limb muscle groups to apply a maximum downward force against a platform moved up and down at high frequency by an electric motor. Thus, these muscle groups accomplished both concentric and eccentric isokinetic contractions in a passive, rapid, and repetitive manner. This study investigates the effects of 10 weeks of PLP training at high and low movement frequencies have on jumping performance, speed, and muscle power. The authors selected 30 college students who had not performed systematic resistance training in the previous 6 months, including traditional resistance training at a squat frequency of 0.5 Hz, PLP training at a low frequency of 0.5 Hz, and PLP training at a high frequency of 2.5 Hz, and randomly divided them into 3 groups (n = 10). The participants' vertical jump, drop jump, 30-m sprint performance, explosive force, and SSC efficiency were tested under the same experimental procedures at pre- and post-training. Results reveal that high-frequency PLP training significantly increased participants' vertical jump, drop jump, 30-m sprint performance, instantaneous force, peak power, and SSC efficiency (p training (p training significantly increased participants' vertical jump, 30-m sprint performance, instantaneous force, and peak power (p training only increased participants' 30-m sprint performance and peak power (p training at high movement frequency. A PLP training machine powered by an electrical motor enables muscles of the lower extremities to contract faster compared with voluntary contraction. Therefore, muscle training with high contraction velocity is one of the main methods of increasing muscle power. Passive leg press training is a unique method for enhancing jump performance, speed, and muscle power.

Process model for ammonia volatilization from anaerobic swine lagoons incorporating varying wind speeds and biogas bubbling

Science.gov (United States)

Ammonia volatilization from treatment lagoons varies widely with the total ammonia concentration, pH, temperature, suspended solids, atmospheric ammonia concentration above the water surface, and wind speed. Ammonia emissions were estimated with a process-based mechanistic model integrating ammonia ...

Performance analysis of wind turbines at low tip-speed ratio using the Betz-Goldstein model

International Nuclear Information System (INIS)

Vaz, Jerson R.P.; Wood, David H.

2016-01-01

Highlights: • General formulations for power and thrust at any tip-speed ratio are developed. • The Joukowsky model for the blades is modified with specific vortex distributions. • Betz-Goldstein model is shown to be the most consistent at low tip-speed ratio. • The effects of finite blade number are assessed using tip loss factors. • Tip loss for finite blade number may complicate the vortex breakdown. - Abstract: Analyzing wind turbine performance at low tip-speed ratio is challenging due to the relatively high level of swirl in the wake. This work presents a new approach to wind turbine analysis including swirl for any tip-speed ratio. The methodology uses the induced velocity field from vortex theory in the general momentum theory, in the form of the turbine thrust and torque equations. Using the constant bound circulation model of Joukowsky, the swirl velocity becomes infinite on the wake centreline even at high tip-speed ratio. Rankine, Vatistas and Delery vortices were used to regularize the Joukowsky model near the centreline. The new formulation prevents the power coefficient from exceeding the Betz-Joukowsky limit. An alternative calculation, based on the varying circulation for Betz-Goldstein optimized rotors is shown to have the best general behavior. Prandtl’s approximation for the tip loss and a recent alternative were employed to account for the effects of a finite number of blades. The Betz-Goldstein model appears to be the only one resistant to vortex breakdown immediately behind the rotor for an infinite number of blades. Furthermore, the dependence of the induced velocity on radius in the Betz-Goldstein model allows the power coefficient to remain below Betz-Joukowsky limit which does not occur for the Joukowsky model at low tip-speed ratio.

An Airbreathing Launch Vehicle Design with Turbine-Based Low-Speed Propulsion and Dual Mode Scramjet High-Speed Propulsion

Science.gov (United States)

Moses, P. L.; Bouchard, K. A.; Vause, R. F.; Pinckney, S. Z.; Ferlemann, S. M.; Leonard, C. P.; Taylor, L. W., III; Robinson, J. S.; Martin, J. G.; Petley, D. H.

1999-01-01

Airbreathing launch vehicles continue to be a subject of great interest in the space access community. In particular, horizontal takeoff and horizontal landing vehicles are attractive with their airplane-like benefits and flexibility for future space launch requirements. The most promising of these concepts involve airframe integrated propulsion systems, in which the external undersurface of the vehicle forms part of the propulsion flowpath. Combining of airframe and engine functions in this manner involves all of the design disciplines interacting at once. Design and optimization of these configurations is a most difficult activity, requiring a multi-discipline process to analytically resolve the numerous interactions among the design variables. This paper describes the design and optimization of one configuration in this vehicle class, a lifting body with turbine-based low-speed propulsion. The integration of propulsion and airframe, both from an aero-propulsive and mechanical perspective are addressed. This paper primarily focuses on the design details of the preferred configuration and the analyses performed to assess its performance. The integration of both low-speed and high-speed propulsion is covered. Structural and mechanical designs are described along with materials and technologies used. Propellant and systems packaging are shown and the mission-sized vehicle weights are disclosed.

Influence of speed and frequency towards the automotive turbocharger turbine performance under pulsating flow conditions

International Nuclear Information System (INIS)

Padzillah, M.H.; Rajoo, S.; Martinez-Botas, R.F.

2014-01-01

Highlights: • 3D CFD modeling of a turbocharger turbine with pulsating flow. • Characterization based on turbine speed and frequency. • Speed has higher influence on turbine performance compared to frequency. • Detailed localized flow behavior are shown for better understanding. - Abstract: The ever-increasing demand for low carbon applications in automotive industry has intensified the development of highly efficient engines and energy recovery devices. Even though there are significant developments in the alternative powertrains such as full electric, their full deployment is hindered by high costing and unattractive life-cycle energy and emission balance. Thus powertrain based on highly efficient internal combustion engines are still considered to be the mainstream for years to come. Traditionally, turbocharger has been an essential tool to boost the engine power, however in recent years it is seen as an enabling technology for engine downsizing. It is a well-known fact that a turbocharger turbine in an internal combustion engine operates in a highly pulsating exhaust flow. There are numerous studies looking into the complex interaction of the pulsating exhaust gas within the turbocharger turbine, however the phenomena is still not fully integrated into the design stage. Industry practice is still to design and match the turbine to an engine based on steady performance maps. The current work is undertaken with the mind to move one step closer towards fully integrating the pulsating flow performance into the turbocharger turbine design. This paper presents the development efforts and results from a full 3-D CFD model of a turbocharger turbine stage. The simulations were conducted at 30,000 rpm and 48,000 rpm (50% and 80% design speed respectively) for both 20 Hz and 80 Hz pulsating flow inlet conditions. Complete validation procedure using cold-flow experimental data is also described. The temporal and spatial resolutions of the incidence angle at the

One process is not enough! A speed-accuracy tradeoff study of recognition memory.

Science.gov (United States)

Boldini, Angela; Russo, Riccardo; Avons, S E

2004-04-01

Speed-accuracy tradeoff (SAT) methods have been used to contrast single- and dual-process accounts of recognition memory. In these procedures, subjects are presented with individual test items and are required to make recognition decisions under various time constraints. In this experiment, we presented word lists under incidental learning conditions, varying the modality of presentation and level of processing. At test, we manipulated the interval between each visually presented test item and a response signal, thus controlling the amount of time available to retrieve target information. Study-test modality match had a beneficial effect on recognition accuracy at short response-signal delays (deep than from shallow processing at study only at relatively long response-signal delays (> or =300 msec). The results are congruent with views suggesting that both fast familiarity and slower recollection processes contribute to recognition memory.

Process of performance assessment

International Nuclear Information System (INIS)

King, C.M.; Halford, D.K.

1987-01-01

Performance assessment is the process used to evaluate the environmental consequences of disposal of radioactive waste in the biosphere. An introductory review of the subject is presented. Emphasis is placed on the process of performance assessment from the standpoint of defining the process. Performance assessment, from evolving experience at DOE sites, has short-term and long-term subprograms, the components of which are discussed. The role of mathematical modeling in performance assessment is addressed including the pros and cons of current approaches. Finally, the system/site/technology issues as the focal point of this symposium are reviewed

Influence of air flow, temperature and agitation speed in the batch acetification process to obtain orange vinegar (Citrus sinensis var.W. Navel

Directory of Open Access Journals (Sweden)

María Ferreyra

2012-03-01

Full Text Available This paper describes the influence of process variables to produce orange vinegar. Orange juice was fermented with Saccharomyces cerevisiae until reach 14% v/v. The biooxidation was carried out with Acetobacter sp., in submerge culture using a laboratory scale fermentor. In order to avoid the inhibitory effect of ethanol on acetic acid bacteria, the orange wine was diluted to 6% v/v with a mineral solution. It was performed a factorial design 2k to study the influence of variables. It was studied air flow rate/agitation at levels of 0.3-0.6 vvm and 200-400 rpm and the effect of air flow rate/temperature at 0.4-0.6 vvm and 25- 30°C, respectively. Duplicate treatments were carried out and the results were evaluated in terms of productivity and fermentation yield. Statistical design (p-value<0.05 was analyzed using Statgraphics Centurion XV Corporate software. Treatments performed at 200 rpm and different air flow levels, did not show significant differences on acetification rate. At higher agitation speed and air flow rates, the productivity was high. The best yields were obtained at lower air flows levels and higher agitation speed. Temperature did not present statistically differences on studied variables. The best yield was obtained at 400 rpm and 0.3 vvm at 25°C. It can be concluded that agitation speed plays an important role for a better acetification rate however higher air flow rates causes less yields.

Motor-cognitive dual-task performance: effects of a concurrent motor task on distinct components of visual processing capacity

OpenAIRE

Künstler, E. C. S.; Finke, K.; Günther, A.; Klingner, C.; Witte, O.; Bublak, P.

2017-01-01

Dual tasking, or the simultaneous execution of two continuous tasks, is frequently associated with a performance decline that can be explained within a capacity sharing framework. In this study, we assessed the effects of a concurrent motor task on the efficiency of visual information uptake based on the ‘theory of visual attention’ (TVA). TVA provides parameter estimates reflecting distinct components of visual processing capacity: perceptual threshold, visual processing speed, and visual sh...

State-Space Modeling and Performance Analysis of Variable-Speed Wind Turbine Based on a Model Predictive Control Approach

Directory of Open Access Journals (Sweden)

H. Bassi

2017-04-01

Full Text Available Advancements in wind energy technologies have led wind turbines from fixed speed to variable speed operation. This paper introduces an innovative version of a variable-speed wind turbine based on a model predictive control (MPC approach. The proposed approach provides maximum power point tracking (MPPT, whose main objective is to capture the maximum wind energy in spite of the variable nature of the wind’s speed. The proposed MPC approach also reduces the constraints of the two main functional parts of the wind turbine: the full load and partial load segments. The pitch angle for full load and the rotating force for the partial load have been fixed concurrently in order to balance power generation as well as to reduce the operations of the pitch angle. A mathematical analysis of the proposed system using state-space approach is introduced. The simulation results using MATLAB/SIMULINK show that the performance of the wind turbine with the MPC approach is improved compared to the traditional PID controller in both low and high wind speeds.

A Comparison Study between Two MPPT Control Methods for a Large Variable-Speed Wind Turbine under Different Wind Speed Characteristics

Directory of Open Access Journals (Sweden)

Dongran Song

2017-05-01

Full Text Available Variable speed wind turbines (VSWTs usually adopt a maximum power point tracking (MPPT method to optimize energy capture performance. Nevertheless, obtained performance offered by different MPPT methods may be affected by the impact of wind turbine (WT’s inertia and wind speed characteristics and it needs to be clarified. In this paper, the tip speed ratio (TSR and optimal torque (OT methods are investigated in terms of their performance under different wind speed characteristics on a 1.5 MW wind turbine model. To this end, the TSR control method based on an effective wind speed estimator and the OT control method are firstly presented. Then, their performance is investigated and compared through simulation test results under different wind speeds using Bladed software. Comparison results show that the TSR control method can capture slightly more wind energy at the cost of high component loads than the other one under all wind conditions. Furthermore, it is found that both control methods present similar trends of power reduction that is relevant to mean wind speed and turbulence intensity. From the obtained results, we demonstrate that, to further improve MPPT capability of large VSWTs, other advanced control methods using wind speed prediction information need to be addressed.

High speed imaging of dynamic processes with a switched source x-ray CT system

International Nuclear Information System (INIS)

Thompson, William M; Lionheart, William R B; Morton, Edward J; Cunningham, Mike; Luggar, Russell D

2015-01-01

Conventional x-ray computed tomography (CT) scanners are limited in their scanning speed by the mechanical constraints of their rotating gantries and as such do not provide the necessary temporal resolution for imaging of fast-moving dynamic processes, such as moving fluid flows. The Real Time Tomography (RTT) system is a family of fast cone beam CT scanners which instead use multiple fixed discrete sources and complete rings of detectors in an offset geometry. We demonstrate the potential of this system for use in the imaging of such high speed dynamic processes and give results using simulated and real experimental data. The unusual scanning geometry results in some challenges in image reconstruction, which are overcome using algebraic iterative reconstruction techniques and explicit regularisation. Through the use of a simple temporal regularisation term and by optimising the source firing pattern, we show that temporal resolution of the system may be increased at the expense of spatial resolution, which may be advantageous in some situations. Results are given showing temporal resolution of approximately 500 µs with simulated data and 3 ms with real experimental data. (paper)

Developmental Steps in Metaphorical Language Abilities: The Influence of Age, Gender, Cognitive Flexibility, Information Processing Speed, and Analogical Reasoning.

Science.gov (United States)

Willinger, Ulrike; Deckert, Matthias; Schmöger, Michaela; Schaunig-Busch, Ines; Formann, Anton K; Auff, Eduard

2017-12-01

Metaphor is a specific type of figurative language that is used in various important fields such as in the work with children in clinical or teaching contexts. The aim of the study was to investigate the developmental course, developmental steps, and possible cognitive predictors regarding metaphor processing in childhood and early adolescence. One hundred sixty-four typically developing children (7-year-olds, 9-year-olds) and early adolescents (11-year-olds) were tested for metaphor identification, comprehension, comprehension quality, and preference by the Metaphoric Triads Task as well as for analogical reasoning, information processing speed, cognitive flexibility under time pressure, and cognitive flexibility without time pressure. Metaphor identification and comprehension consecutively increased with age. Eleven-year-olds showed significantly higher metaphor comprehension quality and preference scores than seven- and nine-year-olds, whilst these younger age groups did not differ. Age, cognitive flexibility under time pressure, information processing speed, analogical reasoning, and cognitive flexibility without time pressure significantly predicted metaphor comprehension. Metaphorical language ability shows an ongoing development and seemingly changes qualitatively at the beginning of early adolescence. These results can possibly be explained by a greater synaptic reorganization in early adolescents. Furthermore, cognitive flexibility under time pressure and information processing speed possibly facilitate the ability to adapt metaphor processing strategies in a flexible, quick, and appropriate way.

Effect of speed endurance and strength training on performance, running economy and muscular adaptations in endurance-trained runners

DEFF Research Database (Denmark)

Vorup Petersen, Jacob; Tybirk, Jonas; Gunnarsson, Thomas Petursson

2016-01-01

PURPOSE: To investigate the effects of combined strength and speed endurance (SE) training along with a reduced training volume on performance, running economy and muscular adaptations in endurance-trained runners. METHODS: Sixteen male endurance runners (VO2-max: ~60 ml kg(-1) min(-1)) were rand...... and speed endurance training, along with a reduced training volume, can improve short-term exercise capacity and induce muscular adaptations related to anaerobic capacity in endurance-trained runners.......PURPOSE: To investigate the effects of combined strength and speed endurance (SE) training along with a reduced training volume on performance, running economy and muscular adaptations in endurance-trained runners. METHODS: Sixteen male endurance runners (VO2-max: ~60 ml kg(-1) min(-1)) were...... randomly assigned to either a combined strength and SE training (CSS; n = 9) or a control (CON; n = 7) group. For 8 weeks, CSS replaced their normal moderate-intensity training (~63 km week(-1)) with SE (2 × week(-1)) and strength training (2 × week(-1)) as well as aerobic high (1 × week(-1)) and moderate...

High-Speed On-Board Data Processing for Science Instruments: HOPS

Science.gov (United States)

Beyon, Jeffrey

2015-01-01

The project called High-Speed On-Board Data Processing for Science Instruments (HOPS) has been funded by NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) program during April, 2012 â€" April, 2015. HOPS is an enabler for science missions with extremely high data processing rates. In this three-year effort of HOPS, Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) and 3-D Winds were of interest in particular. As for ASCENDS, HOPS replaces time domain data processing with frequency domain processing while making the real-time on-board data processing possible. As for 3-D Winds, HOPS offers real-time high-resolution wind profiling with 4,096-point fast Fourier transform (FFT). HOPS is adaptable with quick turn-around time. Since HOPS offers reusable user-friendly computational elements, its FPGA IP Core can be modified for a shorter development period if the algorithm changes. The FPGA and memory bandwidth of HOPS is 20 GB/sec while the typical maximum processor-to-SDRAM bandwidth of the commercial radiation tolerant high-end processors is about 130-150 MB/sec. The inter-board communication bandwidth of HOPS is 4 GB/sec while the effective processor-to-cPCI bandwidth of commercial radiation tolerant high-end boards is about 50-75 MB/sec. Also, HOPS offers VHDL cores for the easy and efficient implementation of ASCENDS and 3-D Winds, and other similar algorithms. A general overview of the 3-year development of HOPS is the goal of this presentation.

Development of High-speed Visualization System of Hypocenter Data Using CUDA-based GPU computing

Science.gov (United States)

Kumagai, T.; Okubo, K.; Uchida, N.; Matsuzawa, T.; Kawada, N.; Takeuchi, N.

2014-12-01

After the Great East Japan Earthquake on March 11, 2011, intelligent visualization of seismic information is becoming important to understand the earthquake phenomena. On the other hand, to date, the quantity of seismic data becomes enormous as a progress of high accuracy observation network; we need to treat many parameters (e.g., positional information, origin time, magnitude, etc.) to efficiently display the seismic information. Therefore, high-speed processing of data and image information is necessary to handle enormous amounts of seismic data. Recently, GPU (Graphic Processing Unit) is used as an acceleration tool for data processing and calculation in various study fields. This movement is called GPGPU (General Purpose computing on GPUs). In the last few years the performance of GPU keeps on improving rapidly. GPU computing gives us the high-performance computing environment at a lower cost than before. Moreover, use of GPU has an advantage of visualization of processed data, because GPU is originally architecture for graphics processing. In the GPU computing, the processed data is always stored in the video memory. Therefore, we can directly write drawing information to the VRAM on the video card by combining CUDA and the graphics API. In this study, we employ CUDA and OpenGL and/or DirectX to realize full-GPU implementation. This method makes it possible to write drawing information to the VRAM on the video card without PCIe bus data transfer: It enables the high-speed processing of seismic data. The present study examines the GPU computing-based high-speed visualization and the feasibility for high-speed visualization system of hypocenter data.

High speed atom source

International Nuclear Information System (INIS)

Hoshino, Hitoshi.

1990-01-01

In a high speed atom source, since the speed is not identical between ions and electrons, no sufficient neutralizing effect for ionic rays due to the mixing of the ionic rays and the electron rays can be obtained failing to obtain high speed atomic rays at high density. In view of the above, a speed control means is disposed for equalizing the speed of ions forming ionic rays and the speed of electrons forming electron rays. Further, incident angle of the electron rays and/or ionic rays to a magnet or an electrode is made variable. As a result, the relative speed between the ions and the electrons to the processing direction is reduced to zero, in which the probability of association between the ions and the electrons due to the coulomb force is increased to improve the neutralizing efficiency to easily obtain fine and high density high speed electron rays. Further, by varying the incident angle, a track capable of obtaining an ideal mixing depending on the energy of the neutralized ionic rays is formed. Since the high speed electron rays has such high density, they can be irradiated easily to the minute region of the specimen. (N.H.)

Multi-channel logical circuit module used for high-speed, low amplitude signals processing and QDC gate signals generation

International Nuclear Information System (INIS)

Su Hong; Li Xiaogang; Zhu Haidong; Ma Xiaoli; Yin Weiwei; Li Zhuyu; Jin Genming; Wu Heyu

2001-01-01

A new kind of logical circuit will be introduced in brief. There are 16 independent channels in the module. The module receives low amplitude signals(≥40 mV), and processes them to amplify, shape, delay, sum and etc. After the processing each channel produces 2 pairs of ECL logical signal to feed the gate of QDC as the gate signal of QDC. The module consists of high-speed preamplifier unit, high-speed discriminate unit, delaying and shaping unit, summing unit and trigger display unit. The module is developed for 64 CH. 12 BIT Multi-event QDC. The impedance of QDC is 110 Ω. Each gate signal of QDC requires a pair of differential ECL level, Min. Gate width 30 ns and Max. Gate width 1 μs. It has showed that the outputs of logical circuit module satisfy the QDC requirements in experiment. The module can be used on data acquisition system to acquire thousands of data at high-speed ,high-density and multi-parameter, in heavy particle nuclear physics experiment. It also can be used to discriminate multi-coincidence events

Effects of Chewing on Cognitive Processing Speed

Science.gov (United States)

Hirano, Yoshiyuki; Obata, Takayuki; Takahashi, Hidehiko; Tachibana, Atsumichi; Kuroiwa, Daigo; Takahashi, Toru; Ikehira, Hiroo; Onozuka, Minoru

2013-01-01

In recent years, chewing has been discussed as producing effects of maintaining and sustaining cognitive performance. We have reported that chewing may improve or recover the process of working memory; however, the mechanisms underlying these phenomena are still to be elucidated. We investigated the effect of chewing on aspects of attention and…

Cognitive Aging in the Seattle Longitudinal Study: Within-Person Associations of Primary Mental Abilities with Psychomotor Speed and Cognitive Flexibility

Directory of Open Access Journals (Sweden)

Gizem Hülür

2016-09-01

Full Text Available It has long been proposed that cognitive aging in fluid abilities is driven by age-related declines of processing speed. Although study of between-person associations generally supports this view, accumulating longitudinal between-person and within-person evidence indicates less strong associations between speed and fluid cognitive performance. Initial evidence also suggests that cognitive flexibility may explain within-person variability in cognitive performance. In the present study, we used up to nine waves of data over 56 years from a subsample of 582 participants of the Seattle Longitudinal Study to examine (a within-person associations of psychomotor speed and cognitive flexibility with cognitive aging in primary mental abilities (including inductive reasoning, number ability, verbal meaning, spatial orientation, and word fluency; and (b how these within-person associations change with age. In line with the processing speed theory, results revealed that within persons, primary mental abilities (including fluid, crystallized, and visualization measures were indeed associated with psychomotor speed. We also observed age-related increases in within-person couplings between primary mental abilities and psychomotor speed. While the processing speed theory focuses primarily on associations with fluid abilities, age-related increases in coupling were found for a variety of ability domains. Within-person associations between primary mental abilities and cognitive flexibility were weaker and relatively stable with age. We discuss the role of speed and flexibility for cognitive aging.

The cognitive effects of listening to background music on older adults: processing speed improves with upbeat music, while memory seems to benefit from both upbeat and downbeat music

OpenAIRE

Bottiroli, Sara; Rosi, Alessia; Russo, Riccardo; Vecchi, Tomaso; Cavallini, Elena

2014-01-01

Background music refers to any music played while the listener is performing another activity. Most studies on this effect have been conducted on young adults, while little attention has been paid to the presence of this effect in older adults. Hence, this study aimed to address this imbalance by assessing the impact of different types of background music on cognitive tasks tapping declarative memory and processing speed in older adults. Overall, background music tended to improve performance...

Performance Analysis of Modified Drain Gating Techniques for Low Power and High Speed Arithmetic Circuits

Directory of Open Access Journals (Sweden)

Shikha Panwar

2014-01-01

Full Text Available This paper presents several high performance and low power techniques for CMOS circuits. In these design methodologies, drain gating technique and its variations are modified by adding an additional NMOS sleep transistor at the output node which helps in faster discharge and thereby providing higher speed. In order to achieve high performance, the proposed design techniques trade power for performance in the delay critical sections of the circuit. Intensive simulations are performed using Cadence Virtuoso in a 45 nm standard CMOS technology at room temperature with supply voltage of 1.2 V. Comparative analysis of the present circuits with standard CMOS circuits shows smaller propagation delay and lesser power consumption.

Measure Guideline: Replacing Single-Speed Pool Pumps with Variable Speed Pumps for Energy Savings

Energy Technology Data Exchange (ETDEWEB)

Hunt, A.; Easley, S.

2012-05-01

The report evaluates potential energy savings by replacing traditional single-speed pool pumps with variable speed pool pumps, and provide a basic cost comparison between continued uses of traditional pumps verses new pumps. A simple step-by-step process for inspecting the pool area and installing a new pool pump follows.

Ride performance of a high speed rail vehicle using controlled semi active suspension system

Science.gov (United States)

Sharma, Sunil Kumar; Kumar, Anil

2017-05-01

The rail-wheel interaction in a rail vehicle running at high speed results in large amplitude vibration of carbody that deteriorates the ride comfort of travellers. The role of suspension system is crucial to provide an acceptable level of ride performance. In this context, an existing rail vehicle is modelled in vertical, pitch and roll motions of carbody and bogies. Additionally, nonlinear stiffness and damping parameters of passive suspension system are defined based on experimental data. In the secondary vertical suspension system, a magneto-rheological (MR) damper is included to improve the ride quality and comfort. The parameters of MR damper depend on the current, amplitude and frequency of excitations. At different running speeds, three semi-active suspension strategies with MR damper are analysed for periodic track irregularity and the resulting performance indices are juxtaposed with the nonlinear passive suspension system. The disturbance rejection and force tracking damper controller algorithms are applied to control the desired force of MR damper. This study reveals that the vertical vibrations of a vehicle can be reduced significantly by using the proposed semi-active suspension strategies. Moreover, it naturally results in improved ride quality and passenger’s comfort in comparison to the existing passive system.

Estimation of effective wind speed

Science.gov (United States)

Østergaard, K. Z.; Brath, P.; Stoustrup, J.

2007-07-01

The wind speed has a huge impact on the dynamic response of wind turbine. Because of this, many control algorithms use a measure of the wind speed to increase performance, e.g. by gain scheduling and feed forward. Unfortunately, no accurate measurement of the effective wind speed is online available from direct measurements, which means that it must be estimated in order to make such control methods applicable in practice. In this paper a new method is presented for the estimation of the effective wind speed. First, the rotor speed and aerodynamic torque are estimated by a combined state and input observer. These two variables combined with the measured pitch angle is then used to calculate the effective wind speed by an inversion of a static aerodynamic model.

Rupture Speed and Dynamic Frictional Processes for the 1995 ML4.1 Shacheng, Hebei, China, Earthquake Sequence

Science.gov (United States)

Liu, B.; Shi, B.

2010-12-01

An earthquake with ML4.1 occurred at Shacheng, Hebei, China, on July 20, 1995, followed by 28 aftershocks with 0.9≤ML≤4.0 (Chen et al, 2005). According to ZÚÑIGA (1993), for the 1995 ML4.1 Shacheng earthquake sequence, the main shock is corresponding to undershoot, while aftershocks should match overshoot. With the suggestion that the dynamic rupture processes of the overshoot aftershocks could be related to the crack (sub-fault) extension inside the main fault. After main shock, the local stresses concentration inside the fault may play a dominant role in sustain the crack extending. Therefore, the main energy dissipation mechanism should be the aftershocks fracturing process associated with the crack extending. We derived minimum radiation energy criterion (MREC) following variational principle (Kanamori and Rivera, 2004)(ES/M0')min≧[3M0/(ɛπμR3)](v/β)3, where ES and M0' are radiated energy and seismic moment gained from observation, μ is the modulus of fault rigidity, ɛ is the parameter of ɛ=M0'/M0,M0 is seismic moment and R is rupture size on the fault, v and β are rupture speed and S-wave speed. From II and III crack extending model, we attempt to reconcile a uniform expression for calculate seismic radiation efficiency ηG, which can be used to restrict the upper limit efficiency and avoid the non-physics phenomenon that radiation efficiency is larger than 1. In ML 4.1 Shacheng earthquake sequence, the rupture speed of the main shock was about 0.86 of S-wave speed β according to MREC, closing to the Rayleigh wave speed, while the rupture speeds of the remained 28 aftershocks ranged from 0.05β to 0.55β. The rupture speed was 0.9β, and most of the aftershocks are no more than 0.35β using II and III crack extending model. In addition, the seismic radiation efficiencies for this earthquake sequence were: for the most aftershocks, the radiation efficiencies were less than 10%, inferring a low seismic efficiency, whereas the radiation efficiency

High-Speed General Purpose Genetic Algorithm Processor.

Science.gov (United States)

Hoseini Alinodehi, Seyed Pourya; Moshfe, Sajjad; Saber Zaeimian, Masoumeh; Khoei, Abdollah; Hadidi, Khairollah

2016-07-01

In this paper, an ultrafast steady-state genetic algorithm processor (GAP) is presented. Due to the heavy computational load of genetic algorithms (GAs), they usually take a long time to find optimum solutions. Hardware implementation is a significant approach to overcome the problem by speeding up the GAs procedure. Hence, we designed a digital CMOS implementation of GA in [Formula: see text] process. The proposed processor is not bounded to a specific application. Indeed, it is a general-purpose processor, which is capable of performing optimization in any possible application. Utilizing speed-boosting techniques, such as pipeline scheme, parallel coarse-grained processing, parallel fitness computation, parallel selection of parents, dual-population scheme, and support for pipelined fitness computation, the proposed processor significantly reduces the processing time. Furthermore, by relying on a built-in discard operator the proposed hardware may be used in constrained problems that are very common in control applications. In the proposed design, a large search space is achievable through the bit string length extension of individuals in the genetic population by connecting the 32-bit GAPs. In addition, the proposed processor supports parallel processing, in which the GAs procedure can be run on several connected processors simultaneously.

A high sensitivity 20Mfps CMOS image sensor with readout speed of 1Tpixel/sec for visualization of ultra-high speed phenomena

Science.gov (United States)

Kuroda, R.; Sugawa, S.

2017-02-01

Ultra-high speed (UHS) CMOS image sensors with on-chop analog memories placed on the periphery of pixel array for the visualization of UHS phenomena are overviewed in this paper. The developed UHS CMOS image sensors consist of 400H×256V pixels and 128 memories/pixel, and the readout speed of 1Tpixel/sec is obtained, leading to 10 Mfps full resolution video capturing with consecutive 128 frames, and 20 Mfps half resolution video capturing with consecutive 256 frames. The first development model has been employed in the high speed video camera and put in practical use in 2012. By the development of dedicated process technologies, photosensitivity improvement and power consumption reduction were simultaneously achieved, and the performance improved version has been utilized in the commercialized high-speed video camera since 2015 that offers 10 Mfps with ISO16,000 photosensitivity. Due to the improved photosensitivity, clear images can be captured and analyzed even under low light condition, such as under a microscope as well as capturing of UHS light emission phenomena.

Performance analysis of PM synchronous motor using fuzzy logic and self tuning fuzzy PI speed controls

International Nuclear Information System (INIS)

Karakaya, A.; Karakas, E.

2008-01-01

Permanent Magnet Synchronous Motors have nonlinear characteristics whose dynamics changes with time. In spite of this structure the permanent magnet synchronous motor has answered engineering problems in industry such as motion control which need high torque values. This paper obtains a nonlinear mathematical model for Permanent Magnet Synchronous Motor and realizes stimulation of the obtained model in the Matlab/Simulink program. Motor parameters are determined by an experimental set-up and they are used in the motor model. Speed control of motor model is made with Fuzzy Logic and Self Tuning logic PI controllers. Using the speed graphs obtained, rise time, overshoot, steady-state error and settling time are analyzed and controller performances are compared. (author)

Physical activity in the elderly is associated with improved executive function and processing speed: the LADIS Study

NARCIS (Netherlands)

Frederiksen, K.S.; Verdelho, A.; Madureira, S.; Bazner, H.; O'Brien, J. T.; Fazekas, F.; Scheltens, P.; Schmidt, R.; Wallin, A.; Wahlund, L.O.; Erkinjunttii, T.; Poggesi, A.; Pantoni, L.; Inzitari, D.; Waldemar, G.

2015-01-01

Objectives Physical activity reduces the risk of cognitive decline but may affect cognitive domains differently. We examined whether physical activity modifies processing speed, executive function and memory in a population of non-dementia elderly subjects with age-related white matter changes

Landscape structure and the speed of adaptation

International Nuclear Information System (INIS)

Claudino, Elder S.; Campos, Paulo R.A.

2014-01-01

The role of fragmentation in the adaptive process is addressed. We investigate how landscape structure affects the speed of adaptation in a spatially structured population model. As models of fragmented landscapes, here we simulate the percolation maps and the fractal landscapes. In the latter the degree of spatial autocorrelation can be suited. We verified that fragmentation can effectively affect the adaptive process. The examination of the fixation rates and speed of adaptation discloses the dichotomy exhibited by percolation maps and fractal landscapes. In the latter, there is a smooth change in the pace of the adaptation process, as the landscapes become more aggregated higher fixation rates and speed of adaptation are obtained. On the other hand, in random percolation the geometry of the percolating cluster matters. Thus, the scenario depends on whether the system is below or above the percolation threshold. - Highlights: • The role of fragmentation on the adaptive process is addressed. • Our approach makes the linkage between population genetics and landscape ecology. • Fragmentation affects gene flow and thus influences the speed of adaptation. • The level of clumping determines how the speed of adaptation is influenced

Measure Guideline. Replacing Single-Speed Pool Pumps with Variable Speed Pumps for Energy Savings

Energy Technology Data Exchange (ETDEWEB)

Hunt, A. [Building Media and the Building America Retrofit Alliance (BARA), Wilmington, DE (United States); Easley, S. [Building Media and the Building America Retrofit Alliance (BARA), Wilmington, DE (United States)

2012-05-01

This measure guideline evaluates potential energy savings by replacing traditional single-speed pool pumps with variable speed pool pumps, and provides a basic cost comparison between continued uses of traditional pumps verses new pumps. A simple step-by-step process for inspecting the pool area and installing a new pool pump follows.

Material requirements for the High Speed Civil Transport

Science.gov (United States)

Stephens, Joseph R.; Hecht, Ralph J.; Johnson, Andrew M.

1993-01-01

Under NASA-sponsored High Speed Research (HSR) programs, the materials and processing requirements have been identified for overcoming the environmental and economic barriers of the next generation High Speed Civil Transport (HSCT) propulsion system. The long (2 to 5 hours) supersonic cruise portion of the HSCT cycle will place additional durability requirements on all hot section engine components. Low emissions combustor designs will require high temperature ceramic matrix composite liners to meet an emission goal of less than 5g NO(x) per Kg fuel burned. Large axisymmetric and two-dimensional exhaust nozzle designs are now under development to meet or exceed FAR 36 Stage III noise requirements, and will require lightweight, high temperature metallic, intermetallic, and ceramic matrix composites to reduce nozzle weight and meet structural and acoustic component performance goals. This paper describes and discusses the turbomachinery, combustor, and exhaust nozzle requirements of the High Speed Civil Transport propulsion system.

Interrelationships between Working Memory, Processing Speed, and Language Development in the Age Range 2-4 Years

Science.gov (United States)

Newbury, Jayne; Klee, Thomas; Stokes, Stephanie F.; Moran, Catherine

2016-01-01

Purpose: This study explored associations between working memory and language in children aged 2-4 years. Method: Seventy-seven children aged 24-30 months were assessed on tests measuring language, visual cognition, verbal working memory (VWM), phonological short-term memory (PSTM), and processing speed. A standardized test of receptive and…

Performance of an agricultural tractor in no tillage as a function of displacement speed and the seeders' tire inflation pressure

Energy Technology Data Exchange (ETDEWEB)

Furlani, Carlos Eduardo Angeli; Cortez, Jorge Wilson; Silva, Rouverson Pereira da; Grotta, Danilo Cesar Checchio; Toledo, Anderson de [Universidade Estadual Paulista (UNESP), Jaboticabal, SP (Brazil)], E-mail: furlani@fcav.unesp.br

2008-07-01

The performance of an agricultural tractor under field conditions results from the tire wheel interaction together with its displacement speed. This work was developed to assess the performance of an agricultural tractor under the (75, 70, and 60 psi) tire inflation pressure conditions of a seeder and in two different gears providing speeds of 3.0 and 6.0 km h{sup -1}. The experiment took place at Sao Paulo State University (UNESP), at the Jaboticabal Campus, and was conducted by Laboratory of Machines and Agricultural Mechanization (LAMMA) at the Department of Rural Engineering. The delineation used was entirely randomized in a 2-factor factorial scheme (3 x 2) with 4 repetitions. We also observed that fuel consumption was influenced only by the tractor gear. Energy consumption was greater as speed increased, caused by gear shifting. The displacement speed was greater for the 75-psi pressure due to a lesser slippage in the seeder when under this pressure. Tractor slippage and initial stand did not change with the tested factors. (author)

Design and operation of the LAMPF Auxiliary Controller. High-speed remote processing on the CAMAC dataway

International Nuclear Information System (INIS)

Machen, D.R.

1979-02-01

A CAMAC Auxiliary Controller has been developed to further the concepts of distributed processing in both process control and experiment data-acquisition systems. The Auxiliary Controller is built around a commercially available 16-bit microcomputer and a high-speed bit-sliced microprocessor capable of instruction execution times of 140 ns. The modular nature of the controller allows the user to tailor the controller capabilities to the system problem, while maintaining the interface techniques of the CAMAC Standard

Resources for comparing the speed and performance of medical autocoders

Directory of Open Access Journals (Sweden)

Berman Jules J

2004-06-01

Full Text Available Abstract Background Concept indexing is a popular method for characterizing medical text, and is one of the most important early steps in many data mining efforts. Concept indexing differs from simple word or phrase indexing because concepts are typically represented by a nomenclature code that binds a medical concept to all equivalent representations. A concept search on the term renal cell carcinoma would be expected to find occurrences of hypernephroma, and renal carcinoma (concept equivalents. The purpose of this study is to provide freely available resources to compare speed and performance among different autocoders. These tools consist of: 1 a public domain autocoder written in Perl (a free and open source programming language that installs on any operating system; 2 a nomenclature database derived from the unencumbered subset of the publicly available Unified Medical Language System; 3 a large corpus of autocoded output derived from a publicly available medical text. Methods A simple lexical autocoder was written that parses plain-text into a listing of all 1,2,3, and 4-word strings contained in text, assigning a nomenclature code for text strings that match terms in the nomenclature. The nomenclature used is the unencumbered subset of the 2003 Unified Medical Language System (UMLS. The unencumbered subset of UMLS was reduced to exclude homonymous one-word terms and proper names, resulting in a term/code data dictionary containing about a half million medical terms. The Online Mendelian Inheritance in Man (OMIM, a 92+ Megabyte publicly available medical opus, was used as sample medical text for the autocoder. Results The autocoding Perl script is remarkably short, consisting of just 38 command lines. The 92+ Megabyte OMIM file was completely autocoded in 869 seconds on a 2.4 GHz processor (less than 10 seconds per Megabyte of text. The autocoded output file (9,540,442 bytes contains 367,963 coded terms from OMIM and is distributed with

Efficiency of developing 15–17-year weightlifters’ training process for a one-year macrocycle with the use of various speed and strength training methods

Directory of Open Access Journals (Sweden)

Oleksandr Piven

2017-10-01

Full Text Available Purpose: developed and experimentally tested the construction of the training process of weightlifters of 15–17 years during a one-year macrocycle with the use of various speed and strength training methods. Material & Methods: to the experiment were attracted 30 young weightlifters at the age of 15–17 years, they all had II and III sports categories. Results: it was found that the athletes of the experimental group who used the unconventional training method, using different training regimes – isokinetic, plyometric, half-dynamic, impact method with speed-strength training, which included jumping with various devices in depth and jumping out, after the experiment, they improved their strengths in the amount of the duathlon by 16,5 kg, and also set their own records in contrast to the control group that trained by the traditional method and improved the power results by 7,2 kg. Conclusion: it is established that the use of non-traditional methods for the development of speed-strength qualities of weightlifters, namely, different training regimes – isokinetic, plyometric, half-dynamic, shock method, contributes to the more efficient development of speed-strength qualities, and, consequently, leads to an increase in sports performance in weightlifting.

High-Speed Data Acquisition and Digital Signal Processing System for PET Imaging Techniques Applied to Mammography

Science.gov (United States)

Martinez, J. D.; Benlloch, J. M.; Cerda, J.; Lerche, Ch. W.; Pavon, N.; Sebastia, A.

2004-06-01

This paper is framed into the Positron Emission Mammography (PEM) project, whose aim is to develop an innovative gamma ray sensor for early breast cancer diagnosis. Currently, breast cancer is detected using low-energy X-ray screening. However, functional imaging techniques such as PET/FDG could be employed to detect breast cancer and track disease changes with greater sensitivity. Furthermore, a small and less expensive PET camera can be utilized minimizing main problems of whole body PET. To accomplish these objectives, we are developing a new gamma ray sensor based on a newly released photodetector. However, a dedicated PEM detector requires an adequate data acquisition (DAQ) and processing system. The characterization of gamma events needs a free-running analog-to-digital converter (ADC) with sampling rates of more than 50 Ms/s and must achieve event count rates up to 10 MHz. Moreover, comprehensive data processing must be carried out to obtain event parameters necessary for performing the image reconstruction. A new generation digital signal processor (DSP) has been used to comply with these requirements. This device enables us to manage the DAQ system at up to 80 Ms/s and to execute intensive calculi over the detector signals. This paper describes our designed DAQ and processing architecture whose main features are: very high-speed data conversion, multichannel synchronized acquisition with zero dead time, a digital triggering scheme, and high throughput of data with an extensive optimization of the signal processing algorithms.

RESEARCH OF INFLUENCE OF THE HIGH-SPEED THERMAL PROCESSING REGIMES ON STRUCTURE AND MECHANICAL PROPERTIES OF PIPE STEEL 32G2

Directory of Open Access Journals (Sweden)

A. I. Gordienko

2012-01-01

Full Text Available Researches on influence of high-speed heating temperature, regimes of cooling and temperature of abatement on structure and mechanical properties of pipe steel 32G2 are carried out. Recommendations on the regimes of high-speed thermal processing of steel 32G2 which can be used at manufacturing of seamless pipes are given.

Considering Variable Road Geometry in Adaptive Vehicle Speed Control

Directory of Open Access Journals (Sweden)

Xinping Yan

2013-01-01

Full Text Available Adaptive vehicle speed control is critical for developing Advanced Driver Assistance Systems (ADAS. Vehicle speed control considering variable road geometry has become a hotspot in ADAS research. In this paper, first, an exploration of intrinsic relationship between vehicle operation and road geometry is made. Secondly, a collaborative vehicle coupling model, a road geometry model, and an AVSC, which can respond to variable road geometry in advance, are developed. Then, based on H∞ control method and the minimum energy principle, a performance index is specified by a cost function for the proposed AVSC, which can explicitly consider variable road geometry in its optimization process. The proposed AVSC is designed by the Hamilton-Jacobi Inequality (HJI. Finally, simulations are carried out by combining the vehicle model with the road geometry model, in an aim of minimizing the performance index of the AVSC. Analyses of the simulation results indicate that the proposed AVSC can automatically and effectively regulate speed according to variable road geometry. It is believed that the proposed AVSC can be used to improve the economy, comfort, and safety effects of current ADAS.

Characteristics of Speed Line Cutter and Fringe Analysis of Workpiece Surface

Directory of Open Access Journals (Sweden)

Shuai Wang

2014-02-01

Full Text Available Easy to operate, speed line cutter has a high machining cost performance, so is very popular among the majority of users. The precision of guide rails, screws and nuts used in most of the machines is not high, and the machine control cannot compensate for the screw pitch error, clearance during the transmission and machining error due to electrode wear. Furthermore, control signal may also be lost in control process. The development of speed line cutter focuses on the quality and machining stability of CNC speed line cutter. This article makes an analysis about the impact of machine’s inherent characteristics on machining workpiece surface, and concludes that analysis shall be made on the irregular fringe, therefore to heighten the machining precision.

Development of Neuromorphic Sift Operator with Application to High Speed Image Matching

Science.gov (United States)

Shankayi, M.; Saadatseresht, M.; Bitetto, M. A. V.

2015-12-01

There was always a speed/accuracy challenge in photogrammetric mapping process, including feature detection and matching. Most of the researches have improved algorithm's speed with simplifications or software modifications which increase the accuracy of the image matching process. This research tries to improve speed without enhancing the accuracy of the same algorithm using Neuromorphic techniques. In this research we have developed a general design of a Neuromorphic ASIC to handle algorithms such as SIFT. We also have investigated neural assignment in each step of the SIFT algorithm. With a rough estimation based on delay of the used elements including MAC and comparator, we have estimated the resulting chip's performance for 3 scenarios, Full HD movie (Videogrammetry), 24 MP (UAV photogrammetry), and 88 MP image sequence. Our estimations led to approximate 3000 fps for Full HD movie, 250 fps for 24 MP image sequence and 68 fps for 88MP Ultracam image sequence which can be a huge improvement for current photogrammetric processing systems. We also estimated the power consumption of less than10 watts which is not comparable to current workflows.

High-performance dual-speed CCD camera system for scientific imaging

Science.gov (United States)

Simpson, Raymond W.

1996-03-01

Traditionally, scientific camera systems were partitioned with a `camera head' containing the CCD and its support circuitry and a camera controller, which provided analog to digital conversion, timing, control, computer interfacing, and power. A new, unitized high performance scientific CCD camera with dual speed readout at 1 X 106 or 5 X 106 pixels per second, 12 bit digital gray scale, high performance thermoelectric cooling, and built in composite video output is described. This camera provides all digital, analog, and cooling functions in a single compact unit. The new system incorporates the A/C converter, timing, control and computer interfacing in the camera, with the power supply remaining a separate remote unit. A 100 Mbyte/second serial link transfers data over copper or fiber media to a variety of host computers, including Sun, SGI, SCSI, PCI, EISA, and Apple Macintosh. Having all the digital and analog functions in the camera made it possible to modify this system for the Woods Hole Oceanographic Institution for use on a remote controlled submersible vehicle. The oceanographic version achieves 16 bit dynamic range at 1.5 X 105 pixels/second, can be operated at depths of 3 kilometers, and transfers data to the surface via a real time fiber optic link.

Tuning of the PI Controller Parameters of a PMSG Wind Turbine to Improve Control Performance under Various Wind Speeds

OpenAIRE

Yun-Su Kim; Il-Yop Chung; Seung-Il Moon

2015-01-01

This paper presents a method to seek the PI controller parameters of a PMSG wind turbine to improve control performance. Since operating conditions vary with the wind speed, therefore the PI controller parameters should be determined as a function of the wind speed. Small-signal modeling of a PMSG WT is implemented to analyze the stability under various operating conditions and with eigenvalues obtained from the small-signal model of the PMSG WT, which are coordinated by adjusting the PI con...

Futsal match-related fatigue affects running performance and neuromuscular parameters but not finishing kick speed or accuracy