302 research outputs found
Optimization of Discrete-parameter Multiprocessor Systems using a Novel Ergodic Interpolation Technique
Modern multi-core systems have a large number of design parameters, most of
which are discrete-valued, and this number is likely to keep increasing as chip
complexity rises. Further, the accurate evaluation of a potential design choice
is computationally expensive because it requires detailed cycle-accurate system
simulation. If the discrete parameter space can be embedded into a larger
continuous parameter space, then continuous space techniques can, in principle,
be applied to the system optimization problem. Such continuous space techniques
often scale well with the number of parameters.
We propose a novel technique for embedding the discrete parameter space into
an extended continuous space so that continuous space techniques can be applied
to the embedded problem using cycle accurate simulation for evaluating the
objective function. This embedding is implemented using simulation-based
ergodic interpolation, which, unlike spatial interpolation, produces the
interpolated value within a single simulation run irrespective of the number of
parameters. We have implemented this interpolation scheme in a cycle-based
system simulator. In a characterization study, we observe that the interpolated
performance curves are continuous, piece-wise smooth, and have low statistical
error. We use the ergodic interpolation-based approach to solve a large
multi-core design optimization problem with 31 design parameters. Our results
indicate that continuous space optimization using ergodic interpolation-based
embedding can be a viable approach for large multi-core design optimization
problems.Comment: A short version of this paper will be published in the proceedings of
IEEE MASCOTS 2015 conferenc
Compressing Video Calls using Synthetic Talking Heads
We leverage the modern advancements in talking head generation to propose an
end-to-end system for talking head video compression. Our algorithm transmits
pivot frames intermittently while the rest of the talking head video is
generated by animating them. We use a state-of-the-art face reenactment network
to detect key points in the non-pivot frames and transmit them to the receiver.
A dense flow is then calculated to warp a pivot frame to reconstruct the
non-pivot ones. Transmitting key points instead of full frames leads to
significant compression. We propose a novel algorithm to adaptively select the
best-suited pivot frames at regular intervals to provide a smooth experience.
We also propose a frame-interpolater at the receiver's end to improve the
compression levels further. Finally, a face enhancement network improves
reconstruction quality, significantly improving several aspects like the
sharpness of the generations. We evaluate our method both qualitatively and
quantitatively on benchmark datasets and compare it with multiple compression
techniques. We release a demo video and additional information at
https://cvit.iiit.ac.in/research/projects/cvit-projects/talking-video-compression.Comment: British Machine Vision Conference (BMVC), 202
Microstrip Line Fed Leaky Wave Antenna with Shorting Vias for Wideband Systems
In this work a complex structured shorted vias microstrip leaky wave antenna is designed and analysed. A Leaky wave antenna is a travelling wave structure with complex propagation constant. When shorting vias are loaded in a periodic structure the fundamental resonant mode shows some stop band characteristics and some of the modes will strongly attenuated. Three different types of iterations are examined in this work with and without defected ground structures. The defected ground structure based leaky wave antennas are showing better performance characteristics with respect to efficiency and phase. A micro strip line feeding with impedance of 50 ohms at both ports are providing excellent impedance matching to the conducting path on the microstrip surface. The shorting vias are suppressing certain higher order frequency bands and providing excellent wide band characteristics with low loss
Analytic results for particles with interaction in two dimensions and an external magnetic field
The -dimensional quantum problem of particles (e.g. electrons) with
interaction in a two-dimensional parabolic potential
(e.g. quantum dot) and magnetic field , reduces exactly to solving a
-dimensional problem which is independent of and . An
exact, infinite set of relative mode excitations are obtained for any . The
problem reduces to that of a ficticious particle in a two-dimensional,
non-linear potential of strength , subject to a ficticious magnetic
field , the relative angular momentum.Comment: To appear in Physical Review Letters (in press). RevTeX file. Two
figures available from [email protected] or
[email protected]
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation V: Onboard software, Data Structure, Telemetry and Telecommand
The onboard software and data communication in the RT-2 Experiment onboard
the Coronas-Photon satellite is organized in a hierarchical way to effectively
handle and communicate asynchronous data generated by the X-ray detectors. A
flexible data handling system is organized in the X-ray detector packages
themselves and the processing electronic device, namely RT-2/E, has the
necessary intelligence to communicate with the 3 scientific payloads by issuing
commands and receiving data. It has direct interfacing with the Satellite
systems and issues commands to the detectors and processes the detector data
before sending to the satellite systems. The onboard software is configured
with several novel features like a) device independent communication scheme, b)
loss-less data compression and c) Digital Signal Processor. Functionality of
the onboard software along with the data structure, command structure, complex
processing scheme etc. are discussed in this paper.Comment: 24 pages, 2 figures, Accepted for publication in Experimental
Astronomy (in press
Evaluating bird communities of Western Ghats to plan for a biodiversity friendly development
Reconciling development with conservation of biological diversity has emerged as a significant concern in recent years. This has been primarily attempted through establishment of protected areas taken out of mainstream development, and through regulating impacts of major development projects with the help of environmental impact assessment exercises. We believe that these two instruments need to be complemented by continually providing inputs into the biodiversity implications of ongoing development processes (and accompanying habitat transformations) at the landscape and regional level. It is desirable that such assessment of biodiversity implications is based on a transparent, objective methodology which could be used by a wide range of practitioners working with the emerging decentralized processes of development planning. In this paper we outline such a methodology focussing on birds. This involves assigning a conservation value to bird species based on readily available information on their geographical range, habitat preference, endangerment and taxonomic distinctiveness. This may then be translated into a mean composite conservation value for bird assemblages characteristic of different habitat types. By combining this information with that on ongoing processes of habitat transformations, we can provide an assessment of how development processes are affecting biodiversity values. We illustrate this methodology by assessing the conservation value of 586 bird species of Western Ghats, and a sample of bird assemblages of seven major habitat types of the region. We conclude that the most serious loss of biodiversity value arises in the transformation of montane evergreen shola forests/high altitude grasslands into monoculture plantations
Fano Effect in a Few-Electron Quantum Dot
We have studied the Fano effect in a few-electron quantum dot side-coupled to
a quantum wire. The conductance of the wire, which shows an ordinal
staircase-like quantization without the dot, is modified through the
interference (the Fano effect) and the charging effects. These effects are
utilized to verify the exhaustion of electrons in the dot. The "addition energy
spectrum" of the dot shows a shell structure, indicating that the electron
confinement potential is fairly circular. A rapid sign inversion of the Fano
parameter on the first conductance plateau with the change of the wire gate
voltage has been observed, and explained by introducing a finite width of
dot-wire coupling.Comment: 11 pages, 7 figure
Econometric modeling of tobacco exports in the milieu of changing global and national policy regimes: repercussions on the Indian tobacco sector
IntroductionTobacco, an important commercial crop, plays a crucial role in farmers' incomes and livelihoods to a sizable population and contributes significant exchange earnings to the Indian economy. Currently, India is the second-largest tobacco producer after China, with a production of 758 million kg (13% of global production) and exports of ~190 million kg of tobacco (9% of global tobacco export volume). However, there are uncertainties surrounding the tobacco sector, such as growing public health and environmental issues associated with tobacco production and consumption and changing national and international tobacco-related policy regimes. In this context, the current study investigates the determinants of tobacco exports and geographical shifts in export destinations over the years.MethodsThe statistical models employed are co-integration, and vector error-correlation models to test the short-run and long-run dynamics relationship between tobacco exports and the explanatory variables, and the Markov chain approach to find out geographical shifts in export destinations.Results and discussionThe econometric model estimated the relationship between the tobacco export volume with domestic production, export price, and global demand for Indian tobacco, and investigated the geographical shift in export destinations of tobacco in the context of changing global and national policy regimes on the sector. The econometric modeling framework confirms that there exists a statistically significant relationship between Indian tobacco export demand, domestic production, export price, and world demand for Indian tobacco. The geographical shift was evident in major export destinations during the post-WHO-FCTC (Framework Convention on Tobacco Control) regime. The model findings direct that India should take advantage of the export price, and global demand for tobacco as India ratified WHO-FCTC; there is no scope for horizontal expansion of the area under tobacco. This modeling framework aids as a tool to direct and explore the possible options with a greater emphasis on export-centric farming system in tobacco production by augmenting crop compliance and quality to meet the standards of international markets
Improvement of two traditional Basmati rice varieties for bacterial blight resistance and plant stature through morphological and marker-assisted selection
Bacterial blight (BB) is a major production threat to Basmati, the aromatic rice prized for its unique quality. In order to improve the BB resistance of two elite, traditional BB-susceptible Basmati varieties (Taraori Basmati and Basmati 386), we utilized the strategy of limited marker-assisted backcrossing for introgression of two major BB resistance genes, Xa21 and xa13, coupled with phenotype-based selection for improvement of their plant type and yield. Improved Samba Mahsuri, an elite high-yielding, fine-grain-type BB-resistant rice variety served as donor for BB resistance. Backcross-derived improved Basmati lines at BC1F5 possessing a single resistance gene (i.e. either Xa21 or xa13) displayed moderate resistance to BB, while lines possessing both Xa21 and xa13 showed significantly higher levels of resistance. Two-gene pyramid lines (Xa21 + xa13) possessing good grain and cooking quality similar to their respective traditional Basmati parents, short plant stature (<110 cm plant height) and higher grain yield than the recurrent parent(s) were identified and advanced. This work demonstrates the successful application of marker-assisted selection in conjunction with phenotype-based selection for targeted introgression of multiple resistance genes into traditional Basmati varieties along with improvement of their plant stature and yield
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