Defending Against Microphone-Based Attacks with Personalized Noise

2021 ◽  
Vol 2021 (2) ◽  
pp. 130-150
Author(s):  
Yuchen Liu ◽  
Ziyu Xiang ◽  
Eun Ji Seong ◽  
Apu Kapadia ◽  
Donald S. Williamson
Keyword(s):  
General Purpose ◽  
False Positives ◽  
Signal To Noise ◽  
Physical Defense ◽  
Babble Noise ◽  
Way Of Knowing ◽  
Comprehensive Study

Abstract Voice-activated commands have become a key feature of popular devices such as smartphones, home assistants, and wearables. For convenience, many people configure their devices to be ‘always on’ and listening for voice commands from the user using a trigger phrase such as “Hey Siri,” “Okay Google,” or “Alexa.” However, false positives for these triggers often result in privacy violations with conversations being inadvertently uploaded to the cloud. In addition, malware that can record one’s conversations remains a signifi-cant threat to privacy. Unlike with cameras, which people can physically obscure and be assured of their privacy, people do not have a way of knowing whether their microphone is indeed off and are left with no tangible defenses against voice based attacks. We envision a general-purpose physical defense that uses a speaker to inject specialized obfuscating ‘babble noise’ into the microphones of devices to protect against automated and human based attacks. We present a comprehensive study of how specially crafted, personalized ‘babble’ noise (‘MyBabble’) can be effective at moderate signal-to-noise ratios and can provide a viable defense against microphone based eavesdropping attacks.

The Persian κάρδακες

2012 ◽  
Vol 132 ◽  
pp. 7-21 ◽  
Author(s):  
Michael B. Charles
Keyword(s):  
Ethnically Diverse ◽  
General Purpose ◽  
The Subject ◽  
The Military ◽  
Comprehensive Study

AbstractPersian troops denominated by Greek writers as κάρδακες appear infrequently in our sources for Achaemenid history, though they are recorded as having a substantial presence at Issus (333 BC). A comprehensive study of these troops is lacking and is of potentially great importance to our understanding of the military system of the Achaemenids, particularly after Xerxes' failed enterprise against Greece, and in light of the 10,000 Immortals' general disappearance from the literary record. Whether they were (a) light or heavy infantry and (b) mercenaries or native Persians has long been the subject of debate, with no particularly conclusive results. This study dismisses Strabo as a useful source on the κάρδακες, and attempts to reconcile the divergent source traditions of Arrian, who describes them as , and Callisthenes (recorded by Polybius), who writes of Persian πελτασταί at Issus. From an investigation of a wide variety of texts, together with lexicographical sources, it is possible to conclude that the hitherto enigmatic κάρδακες were general-purpose infantry not dissimilar to Iphicratean πελτασταί, and that, collectively, they constituted an ethnically diverse infantry force.

Use of Adaptive Digital Signal Processing to Improve Speech Communication for Normally Hearing and Hearing-Impaired Subjects

1988 ◽  
Vol 31 (2) ◽  
pp. 265-271 ◽  
Author(s):  
Richard W. Harris ◽  
Robert H. Brey ◽  
Martin S. Robinette ◽  
Douglas M. Chabries ◽  
Richard W. Christiansen ◽  
...  
Keyword(s):  
Word Recognition ◽  
Digital Signal ◽  
Noise Cancellation ◽  
Noise Signal ◽  
Hearing Impaired ◽  
Speech Communication ◽  
Signal To Noise ◽  
Speech Spectrum ◽  
Babble Noise ◽  
Adaptive Noise

A two microphone adaptive digital noise cancellation technique was used to improve word-recognition ability of normally hearing and hearing-impaired subjects in the presence of varying amounts of multitalker speech babble noise and speech spectrum noise. Signal-to-noise ratios varied from -8 dB to + 12 dB in 4 dB increments. The adaptive noise cancellation technique resulted in reducing both the speech babble and speech spectrum noises 18 to 22 dB. This reduction in noise resulted in average improvements in word recognition, at the poorest signal-to-noise ratios, ranging from 37% to 50% for the normally hearing subjects and 27% to 40% for the hearing-impaired subjects. Improvements in word recognition in the presence of speech babble noise as a result of adaptive filtering were just as large or larger than improvements found in the presence of speech spectrum noise. The amount of improvement of word-recognition scores was most pronounced at the least favorable signal-to-noise ratios.

Comparison of the recognition scores of stop and fricative consonants in babble noise between musicians and non-musicians

2020 ◽  
pp. 030573562095361
Author(s):  
Ebtesam Sajjadi ◽  
Ali Mohammadzadeh ◽  
Nushin Sayadi ◽  
Ahmadreza Nazeri ◽  
Seyyed Mehdi Tabatabai
Keyword(s):  
Auditory Processing ◽  
Musical Training ◽  
Signal To Noise ◽  
Speech In Noise ◽  
Babble Noise ◽  
Perceptual Abilities ◽  
The Impact ◽  
Everyday Communication ◽  
Positive Effect

Everyday communication mostly occurs in the presence of various background noises and competing talkers. Studies have shown that musical training could have a positive effect on auditory processing, particularly in challenging listening situations. To our knowledge, no groups have specifically studied the advantage of musical training on perception of consonants in the presence of background noise. We hypothesized that musician advantage in speech in noise processing may also result in enhanced perception of speech units such as consonants in noise. Therefore, this study aimed to compare the recognition of stops and fricatives, which constitute the highest number of Persian consonants, in the presence of 12-talker babble noise between musicians and non-musicians. For this purpose, stops and fricatives presented in the consonant-vowel-consonant format and embedded in three signal-to-noise ratios of 0, −5, and −10 dB. The study was conducted on 40 young listeners (20 musicians and 20 non-musicians) with normal hearing. Our outcome indicated that musicians outperformed the non-musicians in recognition of stops and fricatives in all three signal-to-noise ratios. These findings provide important evidence about the impact of musical instruction on processing of consonants and highlight the role of musical training on perceptual abilities.

Children's Auditory Working Memory Performance in Degraded Listening Conditions

2014 ◽  
Vol 57 (4) ◽  
pp. 1503-1511 ◽  
Author(s):  
Homira Osman ◽  
Jessica R. Sullivan
Keyword(s):  
Working Memory ◽  
Real Time ◽  
Memory Performance ◽  
Low Complexity ◽  
School Age Children ◽  
School Age ◽  
Signal To Noise ◽  
Memory Processes ◽  
Babble Noise ◽  
Digit Recall

Purpose The objectives of this study were to determine (a) whether school-age children with typical hearing demonstrate poorer auditory working memory performance in multitalker babble at degraded signal-to-noise ratios than in quiet; and (b) whether the amount of cognitive demand of the task contributed to differences in performance in noise. It was hypothesized that stressing the working memory system with the presence of noise would impede working memory processes in real time and result in poorer working memory performance in degraded conditions. Method Twenty children with typical hearing between 8 and 10 years old were tested using 4 auditory working memory tasks (Forward Digit Recall, Backward Digit Recall, Listening Recall Primary, and Listening Recall Secondary). Stimuli were from the standardized Working Memory Test Battery for Children. Each task was administered in quiet and in 4-talker babble noise at 0 dB and −5 dB signal-to-noise ratios. Results Children's auditory working memory performance was systematically decreased in the presence of multitalker babble noise compared with quiet. Differences between low-complexity and high-complexity tasks were observed, with children performing more poorly on tasks with greater storage and processing demands. There was no interaction between noise and complexity of task. All tasks were negatively impacted similarly by the addition of noise. Conclusions Auditory working memory performance was negatively impacted by the presence of multitalker babble noise. Regardless of complexity of task, noise had a similar effect on performance. These findings suggest that the addition of noise inhibits auditory working memory processes in real time for school-age children.

scholarly journals The X-ray diffraction beamline MCX at Elettra: a case study of non-destructive analysis on stained glass

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (3) ◽  
pp. 71 ◽  
Author(s):  
Jasper Rikkert Plaisier ◽  
Luca Nodari ◽  
Lara Gigli ◽  
Elena Paz Rebollo San Miguel ◽  
Renzo Bertoncello ◽  
...  
Keyword(s):  
General Purpose ◽  
Stained Glass ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complex Processes ◽  
Non Destructive ◽  
Glass Decoration ◽  
Comprehensive Study

<p class="Abstract"><span lang="EN-US">The MCX beamline at the synchrotron Elettra is the general purpose diffraction beamline that is well suited for non-destructive and innovative X-ray diffraction (XRD) experiments in the field of cultural heritage. The experimental station houses a large number of instruments facilitating a range of different types of analysis. Recently, a comprehensive study of the alteration products in grisaille paints was performed at the beamline. This type of analysis is very important to understand the complex processes involved in the deterioration of this type of glass decoration. An exhaustive characterization of these products and so a full understanding of the mechanism of their formation may lead to the development of new protective materials for conservation and restoration. XRD experiments at the MCX beamline allowed us to recognize the alteration products on the grisailles surface and to propose a mechanism for the formation of alteration patina. Here we present the beamline, its instrumentation and its capabilities by showing an example of the study on grisaille paints. </span></p>

Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 260-261
Author(s):  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Particle Flux ◽  
Unit Area ◽  
Signal To Noise ◽  
Resolution Image ◽  
High Resolution Image ◽  
Pass Through ◽  
Counting Statistics ◽  
The Relationship ◽  
Picture Element

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Hexachlorobenzene toxicity in the monkey ovary: III. Ultrastructure induced by high (10 mg/kg) dose exposure

1991 ◽  
Vol 49 ◽  
pp. 130-131
Author(s):  
A. Singh ◽  
A. Dykeman ◽  
J. Jarrelf ◽  
D. C. Villeneuve
Keyword(s):  
Present Report ◽  
Reproductive Toxicity ◽  
Control Group ◽  
Primate Model ◽  
Human Follicular Fluid ◽  
Thin Sections ◽  
Cynomolgus Monkeys ◽  
Cacodylate Buffer ◽  
Induction Cycle ◽  
Comprehensive Study

Hexachlorobenzene (HCB), a persistent and mobile organochlorine pesticide, occurs in environment. HCB has been shown to be present in human follicular fluid. An objective of the present report, which is part of a comprehensive study on reproductive toxicity of HCB, was to determine the cytologic effects of the compound on ovarian follicles in a primate model.Materials and Methods. Eight Cynomolgus monkeys were housed under controlled conditions at Animal facility of Health and Welfare, Ottawa. Animals were orally administered gelatin capsules containing HCB mixed with glucose in daily dosages of 0.0 or 10 mg/kg b.w. for 90 days; the former was the control group. On the menstrual period following completion of dosing, the monkeys underwent an induction cycle of superovulation. At necropsy, one-half of an ovary from each animal was diced into ca. 2- to 3-mm cubed specimens that were fixed by immersion in 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.3). Subsequent procedures followed to obtain thin sections that were examined in a Hitachi H-7000 electron microscope have been described earlier.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 52-53
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Plastic Strain ◽  
Cell Walls ◽  
Room Temperature ◽  
Mechanical Response ◽  
Biaxial Tension ◽  
Initial Deformation ◽  
Uniaxial Deformation ◽  
Biaxial Deformation ◽  
Stress States ◽  
Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

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