2,025 research outputs found
ElfStore: A Resilient Data Storage Service for Federated Edge and Fog Resources
Edge and fog computing have grown popular as IoT deployments become
wide-spread. While application composition and scheduling on such resources are
being explored, there exists a gap in a distributed data storage service on the
edge and fog layer, instead depending solely on the cloud for data persistence.
Such a service should reliably store and manage data on fog and edge devices,
even in the presence of failures, and offer transparent discovery and access to
data for use by edge computing applications. Here, we present Elfstore, a
first-of-its-kind edge-local federated store for streams of data blocks. It
uses reliable fog devices as a super-peer overlay to monitor the edge
resources, offers federated metadata indexing using Bloom filters, locates data
within 2-hops, and maintains approximate global statistics about the
reliability and storage capacity of edges. Edges host the actual data blocks,
and we use a unique differential replication scheme to select edges on which to
replicate blocks, to guarantee a minimum reliability and to balance storage
utilization. Our experiments on two IoT virtual deployments with 20 and 272
devices show that ElfStore has low overheads, is bound only by the network
bandwidth, has scalable performance, and offers tunable resilience.Comment: 24 pages, 14 figures, To appear in IEEE International Conference on
Web Services (ICWS), Milan, Italy, 201
Quantum scattering cross sections of O() + N collisions for planetary aeronomy
"Hot atoms", which are atoms in their excited states, transfer their energy
to the surrounding atmosphere through collisions. This process of energy
transfer is known as thermalization, and it plays a crucial role in various
astrophysical and atmospheric processes. Thermalization of hot atoms is mainly
governed by the amount of species present in the surrounding atmosphere and the
collision cross-section between the hot atoms and surrounding species. In this
work, we investigated the elastic and inelastic collisions between hot oxygen
atoms and neutral N molecules, relevant to oxygen gas escape from the
martian atmosphere and for characterizing the chemical reactions in hypersonic
flows. We conducted a series of quantum scattering calculations between various
isotopes of O() atoms and N molecules across a range of collision
energies (0.3 to 4 eV), and computed both their differential and collision
cross-sections using quantum timeindependent coupled-channel approach. Our
differential cross-section results indicate a strong preference for forward
scattering over sideways or backward scattering, and this anisotropy in
scattering is further pronounced at higher collision energies. By comparing the
cross-sections of three oxygen isotopes, we find that the heavier isotopes
consistently have larger collision cross-sections than the lighter isotopes
over the entire collision energy range examined. However, for all the isotopes,
the variation of collision cross-section with respect to collision energy is
the same. As a whole, the present study contributes to a better understanding
of the energy distribution and thermalization processes of hot atoms within
atmospheric environments. Specifically, the crosssectional data presented in
this work is directly useful in improving the accuracy of energy relaxation
modeling of O and N collisions over Mars and Venus atmospheres.Comment: 7 pages, 5 figures, 4 tables, submitted to MNRA
Green Approach for Next Generation Computing: A Survey
In the past few years, the Information and Communication Technology sector have made a significant advancement in Cloud Computing technology. The world wide acceptance of Cloud technology can be credited to the various benefits a Cloud offers to its users. The Cloud technology helps in preventing resource wastage to a much greater extent. The authors of this paper wish to explore the concept behind cloud computing, its strategy, and benefits. This paper presents some facts and figures related to cloud and green computing which will help in obtaining the gist of Cloud Computing and in understanding the need of going green in computing
Emission Factors for Continuous Fixed Chimney Bull Trench Brick Kiln (FCBTK) in India
Uncertainty in emissions from brick manufacturing is a major concern and more primary monitoring based datasets are required. This study presents latest emission factors for continuous fixed chimney bull trench brick kilns (FCBTK), which is the main technology used for brick production in India. Stack monitoring of kilns in a typical brick manufacturing cluster in India is carried out to monitor emissions of pollutants like PM, SO2 and CO. Average concentrations of PM, SO2 and CO in the stacks are measured to be 172±76, 114±47 and 484±198 mg/Nm3, respectively. Monitored stack concentrations are used to compute emission factors based on brick production and fuel consumption activities in the cluster. The computed emission factors across different kilns ranged between 0.81-1.18, 0.57-0.71 and 2.07-2.80g/kg of fired bricks for PM, SO2 and CO, respectively. Corresponding emission factors per unit of coal used in brick kilns are found to be in the range of 13-29, 9-15, 40-56 g /kg for PM, SO2 and CO, respectively. The differences in emission factors are mainly due to variations in the quality of coal used by different kilns. Good correlations were observed between changing calorific values, ash and sulphur content of coal and emissions monitored in the kilns. These new factors can be used for improvement in emission inventories and thereafter modelling results for the region
Balanced Deep CCA for Bird Vocalization Detection
Event detection improves when events are captured by two different modalities rather than just one. But to train detection systems on multiple modalities is challenging, in particular when there is abundance of unlabelled data but limited amounts of labeled data. We develop a novel self-supervised learning technique for multi- modal data that learns (hidden) correlations between simultaneously recorded microphone (sound) signals and accelerometer (body vibration) signals. The key objective of this work is to learn useful embeddings associated with high performance in downstream event detection tasks when labeled data is scarce and the audio events of interest — songbird vocalizations — are sparse. We base our approach on deep canonical correlation analysis (DCCA) that suffers from event sparseness. We overcome the sparseness of positive labels by first learning a data sampling model from the labelled data and by applying DCCA on the output it produces. This method that we term balanced DCCA (b-DCCA) improves the performance of the unsupervised embeddings on the down-stream supervised audio detection task compared to classsical DCCA. Because data labels are frequently imbalanced, our method might be of broad utility in low-resource scenarios
Positive Transfer of the Whisper Speech Transformer to Human and Animal Voice Activity Detection
This paper introduces WhisperSeg, utilizing the Whisper Transformer pre-trained for Automatic Speech Recognition (ASR) for human and animal Voice Activity Detection (VAD). Contrary to traditional methods that detect human voice or animal vocalizations from a short audio frame and rely on careful threshold selection, WhisperSeg processes entire spectrograms of long audio and generates plain text representations of onset, offset, and type of voice activity. Processing a longer audio context with a larger network greatly improves detection accuracy from few labeled examples. We further demonstrate a positive transfer of detection performance to new animal species, making our approach viable in the data-scarce multi-species setting.$^{1}
Role of live microbial feed supplements with reference to anaerobic fungi in ruminant productivity: A review
To keep the concept of a safe food supply to the consumers, animal feed industries world over are showing an increasing
interest in the direct-fed microbials (DFM) for improved animal performance in terms of growth or productivity. This becomes
all the more essential in a situation, where a number of the residues of antibiotics and/or other growth stimulants reach in
milk and meat with a number of associated potential risks for the consumers. Hence, in the absence of growth stimulants,
a positive manipulation of the rumen microbial ecosystem to enhance the feedstuff utilization for improved production efficiency
by ruminants has become of much interest to the researchers and entrepreneurs. A few genera of live microbes
(i.e., bacteria, fungi and yeasts in different types of formulations from paste to powder) are infrequently used as DFM for the
domestic ruminants. These DFM products are live microbial feed supplements containing naturally occurring microbes in
the rumen. Among different DFM possibilities, anaerobic rumen fungi (ARF) based additives have been found to improve
ruminant productivity consistently during feeding trials. Administration of ARF during the few trials conducted, led to the
increased weight gain, milk production, and total tract digestibility of feed components in ruminants. Anaerobic fungi in the
rumen display very strong cell-wall degrading cellulolytic and xylanolytic activities through rhizoid development, resulting in
the physical disruption of feed structure paving the way for bacterial action. Significant improvements in the fiber digestibility
were found to coincide with increases in ARF in the rumen indicating their role. Most of the researches based on DFM
have indicated a positive response in nutrient digestion and methane reducing potential during in vivo and/or in vitro supplementation
of ARF as DFM. Therefore, DFM especially ARF will gain popularity but it is necessary that all the strain
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