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1.
As the applications of mobile and ubiquitous technologies have become more extensive, the communication security issues of those applications are emerging as the most important concern. Therefore, studies are active in relation with various techniques and system applications for individual security elements. In this paper, we proposed a new technique which uses the voice features in order to generate mobile one time passwords (OTPs) and generated safe and variable and safe passwords for one time use, using voice information of biometrics, which is used for powerful personal authentication optionally. Also, we performed the availability analysis on homomorphic variability of voice feature points using dendrogram and distribution of 15 users’ voice skip sampling of feature points for the proposed password generation method. And we have described the application cases of the proposed mobile-OTP using skip sampling of voice signal.  相似文献   

2.
Keogh R  Pearson J 《PloS one》2011,6(12):e29221
Visual working memory provides an essential link between past and future events. Despite recent efforts, capacity limits, their genesis and the underlying neural structures of visual working memory remain unclear. Here we show that performance in visual working memory--but not iconic visual memory--can be predicted by the strength of mental imagery as assessed with binocular rivalry in a given individual. In addition, for individuals with strong imagery, modulating the background luminance diminished performance on visual working memory and imagery tasks, but not working memory for number strings. This suggests that luminance signals were disrupting sensory-based imagery mechanisms and not a general working memory system. Individuals with poor imagery still performed above chance in the visual working memory task, but their performance was not affected by the background luminance, suggesting a dichotomy in strategies for visual working memory: individuals with strong mental imagery rely on sensory-based imagery to support mnemonic performance, while those with poor imagery rely on different strategies. These findings could help reconcile current controversy regarding the mechanism and location of visual mnemonic storage.  相似文献   

3.
Chassy P  Gobet F 《PloS one》2011,6(11):e26692
The respective roles of knowledge and search have received considerable attention in the literature on expertise. However, most of the evidence on knowledge has been indirect--e.g., by inferring the presence of chunks in long-term memory from performance in memory recall tasks. Here we provide direct estimates of the amount of monochrestic (single use) and rote knowledge held by chess players of varying skill levels. From a large chess database, we analyzed 76,562 games played in 2008 by individuals ranging from Class B players (average players) to Masters to measure the extent to which players deviate from previously known initial sequences of moves ("openings"). Substantial differences were found in the number of moves known by players of different skill levels, with more expert players knowing more moves. Combined with assumptions independently made about the branching factor in master games, we estimate that masters have memorized about 100,000 opening moves. Our results support the hypothesis that monochrestic knowledge is essential for reaching high levels of expertise in chess. They provide a direct, quantitative estimate of the number of opening moves that players have to know to reach master level.  相似文献   

4.
The study was aimed to investigate whether impending surgery, considered as a stressful life event, might interfere with memory formation like other stress and anxiety conditions do. Results do not support the hypothesis. Implicit and explicit memory performance are both unaffected by presurgery condition and seem influenced, rather, by subjects gender, education and cultural habits. Females perform generally better than males and, regardless of age and sex, higher educated individuals score higher on the explicit memory task. The habits of reading books and doing crosswords are associated to best performance on explicit and implicit memory task respectively.  相似文献   

5.
Alford C  Cox H  Wescott R 《Amino acids》2001,21(2):139-150
Summary. The effects of Red Bull Energy Drink, which includes taurine, glucuronolactone, and caffeine amongst the ingredients, were examined over 3 studies in a total of 36 volunteers. Assessments included psychomotor performance (reaction time, concentration, memory), subjective alertness and physical endurance. When compared with control drinks, Red Bull Energy Drink significantly (P < 0.05) improved aerobic endurance (maintaining 65–75% max. heart rate) and anaerobic performance (maintaining max. speed) on cycle ergometers. Significant improvements in mental performance included choice reaction time, concentration (number cancellation) and memory (immediate recall), which reflected increased subjective alertness. These consistent and wide ranging improvements in performance are interpreted as reflecting the effects of the combination of ingredients. Received March 20, 2000 Accepted May 25, 2000  相似文献   

6.
Although it is commonly known that viruses cannot multiply in food as they need a living host for growth, adenoviruses and corona viruses can reportedly survive on surfaces and food packages for several days. Therefore, food item mishandling could increase the risk of infection. In this cross-sectional study, we assessed the changes in the food purchasing habits, food safety behavior, and food handling practices among Saudi women during the COVID-19 pandemic. The study included 1356 women who were randomly approached via convenience sampling using an anonymous questionnaire distributed through various social media platforms. The variables were described in terms of frequency and percentage, and the Chi-square test was applied to assess the relationship between the dependent and independent variables. Approximately 62.5% of the participants were aware that SARS-CoV-2 is not transmitted via food. Most participants (90%) reported a shift from outdoor to indoor meal preparation, along with avoidance of visits to grocery stores for food purchase (55%) and increased usage of online grocery delivery services (27%). Most participants obtained good overall scores for food safety behavior during grocery shopping (mean score: 10.83±1.62/12 points, 90.25%), grocery unpacking at home (10.60±2.65/13 points, 81.55%), and personal hygiene (28.84±3.16/36 points, 80%). However, a moderate overall score was obtained for food preparation practices (7.77 ±1.91/12 points, 77.7%). Older and/or retired individuals, patients with chronic diseases, and/or individuals living with children showed better food safety behavior and handling practices compared to their counterparts. This study reported good overall food safety behavior and handling practice scores among participants under most categories studied. However, our results highlight the need for more customized public education programs for Saudi women, who are the primary food handlers in most households, particularly during food preparation, to further improve food safety practices and prevent potential food mishandling, which will eventually help preventing the spread of COVID-19.  相似文献   

7.
We have developed a new tool, called fastDNAml, for constructingphylogenetic trees from DNA sequences. The program can be runon a wide variety of computers ranging from Unix workstationsto massively parallel systems, and is available from the RibosomalDatabase Project (RDP) by anonymous FTP. Our program uses amaximum likelihood approach and is based on version 3.3 of Felsenstein'sdnaml program. Several enhancements, including algorithmic changes,significantly improve performance and reduce memory usage, makingit feasible to construct even very large trees. Trees containing40–100 taxa have been easily generated, and phylogeneticestimates are possible even when hundreds of sequences exist.We are currently using the tool to construct a phylogenetictree based on 473 small subunit rRNA sequences from prokaryotes.  相似文献   

8.
Reverse computation is presented here as an important future direction in addressing the challenge of fault tolerant execution on very large cluster platforms for parallel computing. As the scale of parallel jobs increases, traditional checkpointing approaches suffer scalability problems ranging from computational slowdowns to high congestion at the persistent stores for checkpoints. Reverse computation can overcome such problems and is also better suited for parallel computing on newer architectures with smaller, cheaper or energy-efficient memories and file systems. Initial evidence for the feasibility of reverse computation in large systems is presented with detailed performance data from a particle (ideal gas) simulation scaling to 65,536 processor cores and 950 accelerators (GPUs). Reverse computation is observed to deliver very large gains relative to checkpointing schemes when nodes rely on their host processors/memory to tolerate faults at their accelerators. A comparison between reverse computation and checkpointing with measurements such as cache miss ratios, TLB misses and memory usage indicates that reverse computation is hard to ignore as a future alternative to be pursued in emerging architectures.  相似文献   

9.
In the present study we investigated long-term memory for unpleasant, neutral and spider pictures in 15 spider-fearful and 15 non-fearful control individuals using behavioral and electrophysiological measures. During the initial (incidental) encoding, pictures were passively viewed in three separate blocks and were subsequently rated for valence and arousal. A recognition memory task was performed one week later in which old and new unpleasant, neutral and spider pictures were presented. Replicating previous results, we found enhanced memory performance and higher confidence ratings for unpleasant when compared to neutral materials in both animal fearful individuals and controls. When compared to controls high animal fearful individuals also showed a tendency towards better memory accuracy and significantly higher confidence during recognition of spider pictures, suggesting that memory of objects prompting specific fear is also facilitated in fearful individuals. In line, spider-fearful but not control participants responded with larger ERP positivity for correctly recognized old when compared to correctly rejected new spider pictures, thus showing the same effects in the neural signature of emotional memory for feared objects that were already discovered for other emotional materials. The increased fear memory for phobic materials observed in the present study in spider-fearful individuals might result in an enhanced fear response and reinforce negative beliefs aggravating anxiety symptomatology and hindering recovery.  相似文献   

10.
MOTIVATION: Hidden Markov models (HMMs) and generalized HMMs been successfully applied to many problems, but the standard Viterbi algorithm for computing the most probable interpretation of an input sequence (known as decoding) requires memory proportional to the length of the sequence, which can be prohibitive. Existing approaches to reducing memory usage either sacrifice optimality or trade increased running time for reduced memory. RESULTS: We developed two novel decoding algorithms, Treeterbi and Parallel Treeterbi, and implemented them in the TWINSCAN/N-SCAN gene-prediction system. The worst case asymptotic space and time are the same as for standard Viterbi, but in practice, Treeterbi optimally decodes arbitrarily long sequences with generalized HMMs in bounded memory without increasing running time. Parallel Treeterbi uses the same ideas to split optimal decoding across processors, dividing latency to completion by approximately the number of available processors with constant average overhead per processor. Using these algorithms, we were able to optimally decode all human chromosomes with N-SCAN, which increased its accuracy relative to heuristic solutions. We also implemented Treeterbi for Pairagon, our pair HMM based cDNA-to-genome aligner. AVAILABILITY: The TWINSCAN/N-SCAN/PAIRAGON open source software package is available from http://genes.cse.wustl.edu.  相似文献   

11.
Monika Partzsch 《Flora》2011,206(6):550-558
Over the last 20 years, a change in traditional land use practices has taken place in central Germany. Formerly species-rich dry grassland communities have been converted into communities with greatly reduced diversity in many places. Whereas grass species have expanded, several forbs have declined in abundance. For the present study, plant-plant interactions were assessed between the expanding grass Festuca rupicola and the forb Dianthus carthusianorum - two typical, companion grassland species - to ascertain any associated effects of land use change. A competition experiment was set up with replacement design, in which pots were placed in the open field and monitored over two consecutive years. In order to assess the performance of both species in monoculture (D9, F9) and mixture (D3F6, D6F3) the parameters biomass, length of flowering stems, number of flowering stems and number of flowers per individual, or length of panicles, were analyzed. Positive and negative interactions were evaluated using the “Relative Neighbour Effect” index (RNE). To simulate land use by grazing or mowing, individuals in half of the pots were clipped in the first year after sowing. At this time, performance of D. carthusianorum - in terms of length of flowering stems, number of flowering stems and number of flowers - was significantly affected: whereas the first parameter increased, both of the other parameters decreased with increasing presence of the grass species. However, RNE indicated facilitation with a low number of F. rupicola individuals, and competition with a high number of F. rupicola individuals. In contrast, F. rupicola did not show any significant differences in performance with increasing presence of D. carthusianorum, and the RNE switched from neutral interaction to facilitation. In the second year after sowing, the performance of D. carthusianorum in the various treatments did not differ, except for the length of the flowering stems. The simulation of land use practices did not affect the performance of D. carthusianorum, but F. rupicola showed significant differences in biomass and in length of the panicles, as was the case also between monocultures and mixtures. The performance of the grass species was clearly improved in the unclipped treatments. The RNE reflected competition against D. carthusianorum which became reduced in unclipped treatments, while F. rupicola became facilitated. There were no interactions between the different treatments (monocultures and mixtures) and the simulated land use change (clipped and unclipped). Our data suggest that although traditional land use practices, i.e. grazing and mowing, do not affect the development of D. carthusianorum, the abandonment of these practices has improved F. rupicola performance, which has led to the increasingly invasive character of this grass species over the last 20 years.  相似文献   

12.
We developed 17 chloroplast microsatellite markers, which consisted of seven mononucleotide microsatellites with a minimum repeat number of 10 and 10 dinucleotide microsatellites with a minimum repeat number of six, from the complete chloroplast genomic sequence of Cryptomeria japonica. A survey of 45 C. japonica individuals showed the number of alleles ranging from two to 11 alleles and a diversity index ranging from 0.085 to 0.895. Consequently, the 45 C. japonica individuals were divided into 39 haplotypes. These markers will be useful genetic markers in the gene flow analysis and population genetics of C. japonica.  相似文献   

13.
1. Senescence reflects age-dependent changes in residual reproductive value. Annual survival rates of the barn swallow Hirundo rustica L. increased from 1- to 2-year-old individuals, but decreased among 5 years old or older individuals. Estimates of age-dependent reproductive value showed a similar pattern.
2. Longitudinal data from two long-term population studies were used to test whether a number of different measures of performance (condition-dependent morphological traits, migratory performance, reproductive success, intensity of parasitism) changed among individuals when reaching old age.
3. The length of the outermost tail feathers (a secondary sexual character) decreased among old individuals, while two measures of individual developmental instability increased with age. Migratory performance decreased in old barn swallows as reflected by a delay in spring arrival at the breeding grounds. Reproductive performance measured as seasonal reproductive success decreased with age. The intensity of infestations with an haematophagous mite and a mallophagous ectoparasite increased among old barn swallows.
4. These results suggest that the condition-dependent secondary sexual character, developmental stability, and measures of migratory and reproductive performance deteriorated, and the frequency of parasitism increased among old individuals. Ageing was thus associated with a general deterioration of performance.  相似文献   

14.
Decreasing the slope of the dynamic, but not conventional, restitution curves is antifibrillatory. Cardiac memory/accommodation underlies the difference. We measured diastolic interval (DI) and action potential duration (APD) in epicardial, endocardial, and Purkinje tissue from eight dogs. Consecutive 100-stimulus trains were given to study transitions between basic cycle lengths (BCL) ranging from 400 to 1,300 ms. (DI,APD) pairs aligned immediately on the line DI + APD = BCL (64/67) or oscillated (3/67). The shifting effect of up to 10 extrastimuli on restitution curves was also measured. These curves were fit with the equation APD = alpha + beta exp(-DI/tau), where alpha is asymptote, beta is drop, and tau is time constant. Linear regression of the parameters against the number of extrastimuli showed that premature and postmature stimuli decreased and increased alpha and beta and increased and decreased tau, respectively. Analysis of a mathematical model treating memory as an exponentially decreasing shift of restitution curves shows that oscillatory DI,APD is expected with large DeltaBCL, steep restitution slope, or increased cardiac accommodation. The model explains phase shifts and suggests a common mechanism for Purkinje and myocardial electrical alternans.  相似文献   

15.
16.
Studies in children have shown that the genetic influence on cognition is positively correlated with socioeconomic status. Catechol- O -methyltransferase (COMT) Val158Met, a common, functional polymorphism, has been implicated in executive cognition and working memory. Imaging studies have shown that the variant Met allele is associated with more efficient prefrontal cortical processing and better attention but also emotional vulnerability to stress. We hypothesized that COMT Val158Met genotype would interact with years of education (yrs ed), one indicator of socioeconomic adversity, to predict cognitive task performance. We therefore administered the Wechsler Adult Intelligence Scale-Revised (WAIS-R) to 328 community-derived, genotyped, Plains American Indians (mean yrs ed = 12; range = 5–18). We found significant genotypic effects on WAIS-R measures of long-term memory, working memory and attention. The Met allele was associated with improved performance in the Information and Picture Completion subscales; Met/Met homozygotes performed the best. COMT genotype interacted with yrs ed to influence Information and Block Design scores: Met allele carriers' scores improved markedly with increasing yrs ed, whereas the scores of Val/Val individuals were only marginally influenced by yrs ed. There was a crossover of effects at 11–12 yrs ed: in the less educated group, Met allele carriers actually performed worse than Val/Val individuals perhaps because of emotional vulnerability to educational adversity, but in the better educated group, Met allele carriers excelled. Our study in Plains American Indians has shown that COMT Val158Met influences several aspects of cognition and some of its effects are moderated by educational adversity.  相似文献   

17.
Eight polymorphic microsatellite loci were isolated and characterized for the migratory freshwater fish Salminus brasiliensis (Characiformes) and tested on 67 individuals from nine geographically distant locations along the Paraná Basin. The number of alleles per locus ranged from four to 14, with observed heterozygosity estimates ranging from 0·15 to 0·79.  相似文献   

18.
The increasing diversity of the US coupled with the continuing need for information gathered about race/ethnicity require us to re-examine our practices of collecting and tabulating such data, particularly from individuals of mixed heritage. In the context of Census 2000, which allowed people for the first time to identify with multiple race groups, this article focuses on the context of education and looks at high school students’ self-­identification practices on forms. Survey data gathered from 638 freshmen during 1999–2000 at a diverse, public high school in California indicate: there can be high levels of inconsistency in students’ individual identifications depending on question format and response options provided; and, overall demographic counts can greatly vary depending on how multiple-response data are tabulated. Students’ responses raise questions about whether it is possible to attain a high level of measurement reliability when working with a diverse population that includes individuals of mixed ­heritage.  相似文献   

19.
Severe asymptomatic stenosis of the internal carotid artery (ICA) leads to increased incidence of mild cognitive impairment (MCI) likely through silent embolic infarcts and/or chronic hypoperfusion, but the brain dysfunction is poorly understood and difficult to diagnose. Thirty cognitively intact subjects with asymptomatic, severe (≧70%), unilateral stenosis of the ICA were compared with 30 healthy controls, matched for age, sex, cardiovascular risk factors and education level, on a battery of neuropsychiatric tests, voxel-based morphometry of magnetic resonance imaging (MRI), diffusion tensor imaging and brain-wise, seed-based analysis of resting-state functional MRI. Multivariate regression models and multivariate pattern classification (support vector machines) were computed to assess the relationship between connectivity measures and neurocognitive performance. The patients had worse dizziness scores and poorer verbal memory, executive function and complex visuo-spatial performance than controls. Twelve out of the 30 patients (40%) were considered to have MCI. Nonetheless, the leukoaraiosis Sheltens scores, hippocampal and brain volumes were not different between groups. Their whole-brain mean fractional anisotropy (FA) was significantly reduced and regional functional connectivity (Fc) was significantly impaired in the dorsal attention network (DAN), frontoparietal network, sensorimotor network and default mode network. In particular, the Fc strength at the insula of the DAN and the mean FA were linearly related with attention performance and dizziness severity, respectively. The multivariate pattern classification gave over 90% predictive accuracy of individuals with MCI or severe dizziness. Cognitive decline in stroke-free individuals with severe carotid stenosis may arise from nonselective widespread disconnections of long-range, predominantly interhemispheric non-hippocampal pathways. Connectivity measures may serve as both predictors for cases at risk and therapeutic targets for mitigating vascular cognitive impairment.  相似文献   

20.
In this study, we used high-dimensional pattern regression methods based on structural (gray and white matter; GM and WM) and functional (positron emission tomography of regional cerebral blood flow; PET) brain data to identify cross-sectional imaging biomarkers of cognitive performance in cognitively normal older adults from the Baltimore Longitudinal Study of Aging (BLSA). We focused on specific components of executive and memory domains known to decline with aging, including manipulation, semantic retrieval, long-term memory (LTM), and short-term memory (STM). For each imaging modality, brain regions associated with each cognitive domain were generated by adaptive regional clustering. A relevance vector machine was adopted to model the nonlinear continuous relationship between brain regions and cognitive performance, with cross-validation to select the most informative brain regions (using recursive feature elimination) as imaging biomarkers and optimize model parameters. Predicted cognitive scores using our regression algorithm based on the resulting brain regions correlated well with actual performance. Also, regression models obtained using combined GM, WM, and PET imaging modalities outperformed models based on single modalities. Imaging biomarkers related to memory performance included the orbito-frontal and medial temporal cortical regions with LTM showing stronger correlation with the temporal lobe than STM. Brain regions predicting executive performance included orbito-frontal, and occipito-temporal areas. The PET modality had higher contribution to most cognitive domains except manipulation, which had higher WM contribution from the superior longitudinal fasciculus and the genu of the corpus callosum. These findings based on machine-learning methods demonstrate the importance of combining structural and functional imaging data in understanding complex cognitive mechanisms and also their potential usage as biomarkers that predict cognitive status.  相似文献   

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