Spectral Bandwidths of Colour Detection Mechanisms

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 44-44
Author(s):  
M D'Zmura ◽  
K Knoblauch
Keyword(s):  
Optimal Strategy ◽  
Spectral Properties ◽  
Spectral Bandwidth ◽  
Detection Mechanism ◽  
Noise Masking ◽  
New Methods ◽  
Masking Noise ◽  
Detection Mechanisms ◽  
Colour Signals

We measured the spectral properties of human colour detection mechanisms with a noise masking paradigm, using two new methods to overcome a potential artefact of previous procedures. Estimation of the spectral bandwidth mediating detection of binary colour signals (eg orange) would be misleadingly narrow if the observer changes strategy as a function of the colour of the masking noise (eg detecting the red component of an orange signal in yellow noise and vice versa). We induce observers to use a single detection mechanism throughout an experiment by adding either biaxial noise or sectored noise to the signal. With biaxial noise, one can eliminate detectability of an orange signal by a red-sensitive mechanism, for instance, by adding a steady source of noise along a red axis. We then measure the remaining (yellow) sensitivity by adding noise along a second, variable axis. Sectored noise consists of noise samples from sectors of variable width in the colour plane, centred around the signal axis. Detection with the use of off-axis mechanisms is a less optimal strategy with such noise. A decline in the potency of such noise with increasing sector width would suggest that the spectral bandwidth is narrow and nonlinear rather than broad and more nearly linear.

scholarly journals SybilEye: Observer-Assisted Privacy-Preserving Sybil Attack Detection on Mobile Crowdsensing

Information ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 198
Author(s):  
Junhyeok Yun ◽  
Mihui Kim
Keyword(s):  
Mobile Devices ◽  
Privacy Preserving ◽  
Attack Detection ◽  
Sybil Attack ◽  
Detection Mechanism ◽  
Mobile Crowdsensing ◽  
Detection Model ◽  
System A ◽  
Data Processor ◽  
Detection Mechanisms

Mobile crowdsensing is a data collection system using widespread mobile devices with various sensors. The data processor cannot manage all mobile devices participating in mobile crowdsensing. A malicious user can conduct a Sybil attack (e.g., achieve a significant influence through extortion or the generation of fake IDs) to receive an incentive or destroy a system. A mobile crowdsensing system should, thus, be able to detect and block a Sybil attack. Existing Sybil attack detection mechanisms for wireless sensor networks cannot apply directly to mobile crowdsensing owing to the privacy issues of the participants and detection overhead. In this paper, we propose an effective privacy-preserving Sybil attack detection mechanism that distributes observer role to the users. To demonstrate the performance of our mechanism, we implement a Wi-Fi-connection-based Sybil attack detection model and show its feasibility by evaluating the detection performance.

Enhanced processing of threatening stimuli: The case of face recognition

1995 ◽  
Vol 18 (2) ◽  
pp. 304-305
Author(s):  
Linda Mealey
Keyword(s):  
Face Recognition ◽  
Threat Detection ◽  
Detection Mechanism ◽  
Environmental Features ◽  
Context Dependent ◽  
Detection Mechanisms ◽  
Threatening Stimuli

AbstractBecause of their evolutionary importance, threat-detection mechanisms are likely to exist at a variety of levels. A recent study of face recognition suggests that novel stimuli receive enhanced processing when presented as fear-related. This suggests the existence of a complex, context-dependent threat-detection mechanism that can adaptively respond to spatiotemporally varying and unique environmental features.

The normalized correlation: Accounting for NoSπ thresholds with Gaussian and ‘‘low‐noise’’ masking noise

1999 ◽  
Vol 105 (2) ◽  
pp. 1342-1343
Author(s):  
Leslie R. Bernstein ◽  
Steven van de Par ◽  
Constantine Trahiotis
Keyword(s):  
Low Noise ◽  
Noise Masking ◽  
Masking Noise

scholarly journals Electronic Nose: Recent Developments in Gas Sensing and Molecular Mechanisms of Graphene Detection and Other Materials

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 80 ◽  
Author(s):  
Sylwia Orzechowska ◽  
Andrzej Mazurek ◽  
Renata Świsłocka ◽  
Włodzimierz Lewandowski
Keyword(s):  
Electronic Nose ◽  
Molecular Mechanisms ◽  
Electronic System ◽  
Radical Change ◽  
Electronic Charge ◽  
Detection Mechanism ◽  
Electronic Density ◽  
Area Of Interest ◽  
Sensitivity Improvement ◽  
Detection Mechanisms

The aim of the study was to present the possibility of the sensitivity improvement of the electronic nose (e-nose) and to summarize the detection mechanisms of trace gas concentrations. Our main area of interest is graphene, however, for the better understanding of the sensing mechanisms, it is crucial to review other sensors of similar functions. On the basis of our previous research, we explained the detection mechanism which may stay behind the graphene sensor’s sensitivity improvement. We proposed a qualitative interpretation of detection mechanisms in graphene based on the theory regarding the influence of metals and substituents on the electronic systems of carbon rings and heterocyclic aromatic ligands. The analysis of detection mechanisms suggests that an increase of the electronic density in graphene by attaching a substituent and stabilization of electronic charge distribution leads to the increase of graphene sensor conductivity. The complexation of porphyrins with selected metals stabilizes the electronic system and increases the sensitivity and selectivity of porphyrin-based sensors. Our research summary and proposed conclusions allow us to better understand the mechanisms of a radical change of graphene conductivity in the presence of trace amounts of various gases.

scholarly journals New coordination compounds of uranyl ion with 3-(2-hydroxyphenyl)-1,2,4-triazole and its derivatives: synthesis and investigation of spectral properties

2015 ◽  
Vol 3 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Oleksandr Vashchenko ◽  
Dmytro Khomenko ◽  
Roman Doroschuk ◽  
Rostyslav Lampeka
Keyword(s):  
Ir Spectroscopy ◽  
Coordination Compounds ◽  
Spectral Properties ◽  
Complex Compounds ◽  
Uranyl Ion ◽  
New Methods ◽  
Coordination Compounds Of Uranyl

New methods of 3-(2-hydroxyphenyl)-1,2,4-triazoles synthesis were developed. Obtained ligands was used for synthesis of three new complex compounds of uranyl-ion with general composition [UO2(HL)2(Solv)]. These compounds were characterized by NMR and IR spectroscopy.

scholarly journals New methods for capturing the mystery lipid, PtdIns5P

2010 ◽  
Vol 428 (3) ◽  
pp. e1-e2 ◽  
Author(s):  
Jonathan M. Backer
Keyword(s):  
Protein Interactions ◽  
Inositol Phosphate ◽  
Coincidence Detection ◽  
Protein Protein Interactions ◽  
Detection Mechanism ◽  
Intact Cells ◽  
New Methods ◽  
Binding Domains ◽  
Biochemical Journal ◽  
Phox Homology

The enormous versatility of phosphatidylinositol as a mediator of intracellular signalling is due to its variable phosphorylation on every combination of the 3′, 4′ and 5′ positions, as well as an even more complex range of phosphorylated products when inositol phosphate is released by phospholipase C activity. The phosphoinositides are produced by distinct enzymes in distinct intracellular membranes, and recruit and regulate downstream signalling proteins containing binding domains [PH (pleckstrin homology), PX (Phox homology), FYVE etc.] that are relatively specific for these lipids. Specific recruitment of downstream proteins presumably involves a coincidence detection mechanism, in which a combination of lipid–protein and protein–protein interactions define specificity. Of the seven intrucellular phosphoinositide, quantification of PtdIns5P levels in intact cells has remained difficult. In this issue of the Biochemical Journal, Sarkes and Rameh describe a novel HPLC-based approach which makes possible an analysis of the subcellular distribution of PtdIns5P and other phosphoinositides.

scholarly journals What is the role of the medial olivocochlear system in speech-in-noise processing?

2012 ◽  
Vol 107 (5) ◽  
pp. 1301-1312 ◽  
Author(s):  
Jessica de Boer ◽  
A. Roger D. Thornton ◽  
Katrin Krumbholz
Keyword(s):  
Otoacoustic Emissions ◽  
Noise Masking ◽  
Speech In Noise ◽  
Olivocochlear System ◽  
Contralateral Suppression ◽  
Auditory Brain Stem ◽  
Medial Olivocochlear System ◽  
Masking Noise ◽  
Cochlear Gain ◽  
Medial Olivocochlear

The medial olivocochlear (MOC) bundle reduces the gain of the cochlear amplifier through reflexive activation by sound. Physiological results indicate that MOC-induced reduction in cochlear gain can enhance the response to signals when presented in masking noise. Some previous studies suggest that this “antimasking” effect of the MOC system plays a role in speech-in-noise perception. The present study set out to reinvestigate this hypothesis by correlating measures of MOC activity and speech-in-noise processing across a group of normal-hearing participants. MOC activity was measured using contralateral suppression of otoacoustic emissions (OAEs), and speech-in-noise processing was measured by measuring the effect of noise masking on performance in a consonant-vowel (CV) discrimination task and on auditory brain stem responses evoked by a CV syllable. Whereas there was a significant correlation between OAE suppression and both measures of speech-in-noise processing, the direction of this correlation was opposite to that predicted by the antimasking hypothesis, in that individuals with stronger OAE suppression tended to show greater noise-masking effects on CV processing. The current results indicate that reflexive MOC activation is not always beneficial to speech-in-noise processing. We propose an alternative to the antimasking hypothesis, whereby the MOC system benefits speech-in-noise processing through dynamic (e.g., attention- and experience-dependent), rather than reflexive, control of cochlear gain.

scholarly journals Feedforward and Feedback Control in Apraxia of Speech: Effects of Noise Masking on Vowel Production

2015 ◽  
Vol 58 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Edwin Maas ◽  
Marja-Liisa Mailend ◽  
Frank H. Guenther
Keyword(s):  
Auditory Feedback ◽  
Feedback System ◽  
Apraxia Of Speech ◽  
Vowel Production ◽  
Noise Masking ◽  
Acoustic Measures ◽  
Masking Condition ◽  
Masking Noise ◽  
Vowel Contrast ◽  
Group Pattern

Purpose This study was designed to test two hypotheses about apraxia of speech (AOS) derived from the Directions Into Velocities of Articulators (DIVA) model (Guenther et al., 2006): the feedforward system deficit hypothesis and the feedback system deficit hypothesis. Method The authors used noise masking to minimize auditory feedback during speech. Six speakers with AOS and aphasia, 4 with aphasia without AOS, and 2 groups of speakers without impairment (younger and older adults) participated. Acoustic measures of vowel contrast, variability, and duration were analyzed. Results Younger, but not older, speakers without impairment showed significantly reduced vowel contrast with noise masking. Relative to older controls, the AOS group showed longer vowel durations overall (regardless of masking condition) and a greater reduction in vowel contrast under masking conditions. There were no significant differences in variability. Three of the 6 speakers with AOS demonstrated the group pattern. Speakers with aphasia without AOS did not differ from controls in contrast, duration, or variability. Conclusion The greater reduction in vowel contrast with masking noise for the AOS group is consistent with the feedforward system deficit hypothesis but not with the feedback system deficit hypothesis; however, effects were small and not present in all individual speakers with AOS. Theoretical implications and alternative interpretations of these findings are discussed.

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