8,219 research outputs found
Speech Separation Using Partially Asynchronous Microphone Arrays Without Resampling
We consider the problem of separating speech sources captured by multiple
spatially separated devices, each of which has multiple microphones and samples
its signals at a slightly different rate. Most asynchronous array processing
methods rely on sample rate offset estimation and resampling, but these offsets
can be difficult to estimate if the sources or microphones are moving. We
propose a source separation method that does not require offset estimation or
signal resampling. Instead, we divide the distributed array into several
synchronous subarrays. All arrays are used jointly to estimate the time-varying
signal statistics, and those statistics are used to design separate
time-varying spatial filters in each array. We demonstrate the method for
speech mixtures recorded on both stationary and moving microphone arrays.Comment: To appear at the International Workshop on Acoustic Signal
Enhancement (IWAENC 2018
Fusing Binary Interface Defects in Topological Phases: The case
A binary interface defect is any interface between two (not necessarily
invertible) domain walls. We compute all possible binary interface defects in
Kitaev's model and all possible fusions between them.
Our methods can be applied to any Levin-Wen model. We also give physical
interpretations for each of the defects in the model.
These physical interpretations provide a new graphical calculus which can be
used to compute defect fusion.Comment: 27+10 pages, 2+5 tables, comments welcom
Acoustic Impulse Responses for Wearable Audio Devices
We present an open-access dataset of over 8000 acoustic impulse from 160
microphones spread across the body and affixed to wearable accessories. The
data can be used to evaluate audio capture and array processing systems using
wearable devices such as hearing aids, headphones, eyeglasses, jewelry, and
clothing. We analyze the acoustic transfer functions of different parts of the
body, measure the effects of clothing worn over microphones, compare
measurements from a live human subject to those from a mannequin, and simulate
the noise-reduction performance of several beamformers. The results suggest
that arrays of microphones spread across the body are more effective than those
confined to a single device.Comment: To appear at ICASSP 201
Breaking Peroxy Bonds in H20 Ice Doped with H202 to Create Positive Hole Charge Carriers.
Using stress-activated electric conductivity in water ice doped with hydrogen peroxide as a model for stress-activated electric conductivity of igneous and high-grade metamorphic rocks due to the presence of peroxy defects, which when broken, createpositive-hole charge carriers. Blocks of pure H2O ice and H2O2–doped H2O ices, frozen at –20°C, will be stressed with piezo electric transducers(pzt) at one end to generate stress-activated electric currents flowing down the stress gradient. Pure H2O ice should produce no current or a small insignificant amount during rapid deformation or fracture. Stressing H2O2-doped H2O ices, however, should lead to 100-1000 times higher currents. These stress-activated currents are carried by defect electrons, generated by the break-up of the peroxy bonds of H2O2molecules embedded in the ice structure. These defect electrons are associated with the oxygen anion sub-lattice and known as positive holes. H2O2–doped H2O ices can be viewed as analogs to igneous and high-grade metamorphic rocks, which naturally contain peroxy defects, typically O3Si-OO-SiO3, and also produce positive hole currents when subjected to stres
Geological features within the Big Indian Lake pluton, Hants County, Nova Scotia: evidence of igneous layering from recent diamond drilling
This paper describes geological features observed in diamond drill core recovered from three holes in the Big Indian Lake pluton near the eastern margin of the South Mountain Batholith. The pluton is comprised of four texturally variable granitic facies (order of decreasing abundance): (1) megacrystic to equigranular monzogranite and leuco-monzogranite, (2) porphyritic biotite monzogranite, (3) equigranular leucomonzogranite, and (4) microgranitc. Evidence of igneous layering observed in drill core includes: (1) the presence of a cumulate-like aggregate of plagioclase, (2) centimetre-thick layers modally enriched in biotite and apatite, and (3) gradational contacts between granitic rock-types. The plagioclase aggregate contains SO to 90% zoned and generally equidimensional plagioclase crystals which commonly have mutually interfering grain boundaries and a poikilitic texture characterized by abundant biotite inclusions. Contacts of the plagioclase aggregate with other facies of the pluton are generally gradational, and marked by a progressive increase in biotite and decrease in euhedral plagioclase crystals.
The amount of plagioclase-rich aggregate decreases with depth in the drill core, and granodiorite and biotite monzogranite become more abundant. They grade into predominately leucomonzogranite and microgranite at depth. The microgranite is typically of syenogranite composition and closely associated with several types of alteration and mineralization. The common occurrence of pegmatite within the microgranite at boundaries with equigranular leucomonzogranite suggests that the microgranitc crystallized from a highly fractionated, water-saturated liquid. The microgranite may represent a texturally and mineralogically modified leucomonzogranite rather than a primary magmalic product.
The occurrence of what appears to be primary magmatic layering in the Big Indian Lake pluton appears to confirm the relevance of applying fractional crystallization models to the South Mountain Batholith.
RÉSUMÉ
Cet article décrit les caractéristiques géologiques de trois forages dans le pluton du lac Big Indian, près de la bordure est du balholite du mont South. Lc pluton est composé de quatre faciès granitiques de diverses textures (en ordre d'abondanée déeroissante): (1) des monzogranites et leucomonzogranites à mégacristaux ou équigranulaires, (2) des monzonites porphyriques à biotite, (3) des leucomonzogranites équigranulaires et (4) des microgranites. Les indications de litage magmatique observers en forage sont: (1) la présence d'un aggrégat de plagioclase semblable à un cumulat, (2) des lits centimétriques enrichis en biotite et en apatite et (3) des contacts graduels entre les types de granite. L’aggrégat de plagioclase contient de 50 à 90% de cristaux de plagioclase zonés et généralement trapus qui ont communémwnt des contacts enginés et une texture poecilitique avec d'abondantes inclusions de biotite. Les contacts de l'aggrégate plagioclase avec les autres faciès du pluton sont gendralement graduels el sont soulignés par un enrichissement progressif en biotite et un appauvrissement en cristaux de plagioclase euédriques.
La proportion d'aggrégat riche en plagioclase décroit avec la profondeur tandis que la granodiorite et le monzogranite à biotite deviennent plus abondants. Le microgranitc a typiquemenl unc composition de syénogranite et est intimement associé à de l'altération et de la minéralisation. L'abondance de pegmatite au sein du microgranite en contact avec les leucomonzogranites équigranulaires suggère que le microgranite à cristallisé à partir d'un magma très différencié et saturé en eau. Le microgranite pourrait représenter un leucomonzogranite dont la texture et la minéralogie ont été modifiers plutôt qu'un produit magmatique primaire.
Le présence de ce qui est apparemment un litage magmatique primaire dans le pluton du lac Big Indian semble confirmer la pertinence des modèles de cristallisation fractionnée pour le batholite du mont South.
[Traduit par le journal
Faculty collaboration in the planning of first-year composition and linked courses in learning communities at Iowa State University
Detecting Rip Currents from Images
Rip current images are useful for assisting in climate studies but time consuming to manually annotate by hand over thousands of images. Object detection is a possible solution for automatic annotation because of its success and popularity in identifying regions of interest in images, such as human faces. Similarly to faces, rip currents have distinct features that set them apart from other areas of an image, such as more generic patterns of the surf zone. There are many distinct methods of object detection applied in face detection research. In this thesis, the best fit for a rip current object detector is found by comparing these methods. In addition, the methods are improved with Haar features exclusively created for rip current images. The compared methods include max distance from the average, support vector machines, convolutional neural networks, the Viola-Jones object detector, and a meta-learner. The presented results are compared for accuracy, false positive rate, and detection rate. Viola-Jones has the top base-line performance by achieving a detection rate of 0.88 and identifying only 15 false positives in the test image set of 53 rip currents. The described meta-learner integrates the presented Haar features, which are developed in accordance with the original Viola-Jones algorithm. Ada-Boost, a feature ranking algorithm, shows that the newly presented Haar features extract more meaningful data from rip current images than some of the current features. The meta-classifier improves upon the stand-alone Viola-Jones when applying these features by reducing its false positives by 47% while retaining a similar computational cost and detection rate
An occurence of metasomatic aujminosilicates related to high alumina hydrothermal alteration within the South Mountain Batholith, Nova Scotia
A zone of high alumina hydrothermal alteration (HAHA) is documented within granitoid rocks of the Big Indian Polyphase Intrusive suite (BIPI suite), which forms part of the Late Devonian-Early Carboniferous South Mountain Batholith (SHB). The alteration, which la confined to a NE-trending shear zone, is characterized by the quartz-deficient mineral assemblage andalusite-sillimanlte-spinel-oiuscovite-cordierite-apatite-pyrite. The HAHA zone represents the first reported occurrence of this alteration type within the South Mountain Batholith.
Field observations indicate that the HAHA zone is only one of a series of successive and superimposed metasoraatic-hydrothermal events which, together with U-Cu-Ho + U-Cu mineralization, exhibit a transition in style from early pervasive to late fracture-controlled. This change in style within the BIPI suite is considered to reflect a progressive Increase in fluid pressure.
Petrography and mineral chemistry suggest that the HAHA zone formed in response to the interaction of the leuco-monzogranlte host with a Na(+Al)-rich, siliea-undersaturated fluid. Although speculative, alumina may have been a mobile element transported as an alkali-complex via the fluid. High temperature mineral assemblages (gndalusite-aillimanite; andalusite-spinel) Indicate that the initial temperature of the aqueous fluid phase was ≥620oC for 2 kb pressure. It la proposed that the fluid phase represents a residual magmatic-fluid which was accessed by deep-seated fracturing.
RÉSUMÉ
On documenté une zone d'altération hydrothermale hautement alumlneuse (AHHA) à l'intérieur des granitoides de la suite intrusive Polyphasée de Big Indian (suite IPBI) qui fait partie du Batholite de South Mountain (BSM) d'âge tardidévonien à éocarbonifère. Confinée à une zone de cisaillement A tendance NE, l'altération est caractérisée par un assemblage de minéraux, deficient en quartz, à andalousite-sillimanite-spinelie-museovite-cordierite-apatite-pyrite. La zone AHHA représente la première mention de ce type d'altération à l'intérieur du BSM.
D'après les observations sur le terrain, cette zone AHHA n'est qu'un d'une serie d'evenements métasomatiques et hydrothermaux successifs et superposes qui. ainsl qu'une minéralisation en W-Cu-Mo+U-Cu. exbibent un style d'abord pénétrant et enfin filonlen. On consideré que ce changement de style A l'intérieur de la suite IPBI représente un accroissement progressif de la pression des fluides.
La pétrographie et le chimisme des minéraux tendent à montrer que la zone AHHA e'est établie en reponse à l'intersction de l'encaissant leucomonzogranitique avec un fluide sous-sature en silice et riche en Na±Al. Bien que cela reste speculatif, l'alumine pourrait avoir été un élément mobile transports par le fluide à l’état de complexe alcalln. D'après les assemblages de minéraux A haute température (andalousite-sillimanite; andalousite-spinelie), la température inltiale de la phase aqueuse fluide était ≥620oC pour une pression de 2 kb. On propose que la phase fluide représente un fluide magmatique residuel extrait par une fracturation en profondeur.
[Traduit par le journal
- …