682 research outputs found
Pattern of Agricultural Diversification in India
Agricultural diversification as measured by increase in the percent of non-food crops has grown; whereas diversification as measured by the concentration indices has remained unchanged in the recent decade. There have been significant changes in the pattern of agricultural diversification at the regional level. Within a region, smaller sub-regions or pockets of specialization in certain crops and crop-groups have emerged. Farms do not remain diversified and the usual notion of crop diversification as a risk management practice is also belied in the present study. The study also found certain kind of structural changes in all sub-sectors of agriculture : crop, livestock, and fisheries. Concerns over extreme effects of such changes are however, not valid.agricultural diversification, Agriculture Analysis, India, non-food crops, crop, livestock, and fisheries
A study of the long term evolution of quasi periodic oscillations in the accretion powered X-ray pulsar 4U 1626-67
We report here a study of the long term properties of Quasi Periodic
Oscillations (QPO) in an unusual accreting X-ray pulsar, 4U 1626--67. This is a
unique accretion powered X-ray pulsar in which we have found the QPOs to be
present during all sufficiently long X-ray observations with a wide range of
X-ray observatories. In the present spin-down era of this source, the QPO
central frequency is found to be decreasing. In the earlier spin-up era of this
source, there are only two reports of QPO detections, in 1983 with EXOSAT and
1988 with GINGA with an increasing trend. The QPO frequency evolution in 4U
1626--67 during the last 22 years changed from a positive to a negative trend,
somewhat coincident with the torque reversal in this source. In the accretion
powered X-ray pulsars, the QPO frequency is directly related to the inner
radius of the accretion disk, as per Keplerian Frequency Model (KFM) and Beat
Frequency Model (BFM). A gradual depletion of accretion disk is reported
earlier from the X-ray spectral, flux and pulse profile measurements. The
present QPO frequency evolution study shows that X-ray flux and mass accretion
rate may not change by the same factor, hence the simple KFM and BFM are not
able to explain the QPO evolution in this source. This is the only X-ray pulsar
to show persistent QPOs and is also the first accreting X-ray pulsar in which
the QPO history is reported for a long time scale relating it with the long
term evolution of the accretion disk.Comment: 14 pages, 3 figures. Accepted for publication in Ap
Spectrum Sharing and Interference in Smart Homes
Internet of Things networks using Zigbee are very popular in smart homes. However, Zigbee networks are vulnerable to the interference of Wi-Fi networks because they share the same 2.4 GHz Industrial, Scientific, and Medical radio frequency band. Studies have shown that weaker Zigbee signals might be significantly interfered by stronger Wi-Fi signals. This type of interference may cause severe problems when these types of networks coexist in an indoor environment such as in a smart home. In this thesis, the performance of a Zigbee network with and without the presence of a Wi-Fi network has been evaluated in an apartment-based indoor environment mimicking a smart home. The experimental results are obtained and analyzed in terms of received signal strength indicator, packet delay, packet drop rate, and loopback throughput by changing operating channels, distances between Zigbee and Wi-Fi devices, transmission intervals of Zigbee packets, Zigbee transmit power, and Zigbee packet lengths
Tuning of PID controller by bioinspired techniques
PID controllers have been extensively used for a long time for the purpose of process controls.Efficient methods for tuning of PID controllers is still a challange to designers. This project work is based on the development of PID controller for a low damping plant using Bio inspired evolutionary soft computational techniques.We have implemented Particle Swarm Optimization and Bacterial Foraging Optimization techniques to tune the parameters of the PID for a fifth order low damping plant and have done a comparative study of the performance of both the techniques
Higher order two-mode and multi-mode entanglement in Raman processes
The existence of higher order entanglement in the stimulated and spontaneous
Raman processes is established using the perturbative solutions of the
Heisenberg equations of motion for various field modes that are obtained using
the Sen-Mandal technique and a fully quantum mechanical Hamiltonian that
describes the stimulated and spontaneous Raman processes. Specifically, the
perturbative Sen-Mandal solutions are exploited here to show the signature of
the higher order two-mode and multi-mode entanglement. In some special cases,
we have also observed higher order entanglement in the partially spontaneous
Raman processes. Further, it is shown that the depth of the nonclassicality
indicators (parameters) can be manipulated by the specific choice of coupling
constants, and it is observed that the depth of nonclassicality parameters
increases with the order.Comment: 9 pages, 5 figures. arXiv admin note: text overlap with
arXiv:1301.028
Challenges and gaps for energy planning models in the developing-world context
Energy planning models (EPMs) support multi-criteria assessments of the impact of energy policies on the economy and environment. Most EPMs have originated in developed countries and are primarily aimed at reducing greenhouse gas emissions while enhancing energy security. In contrast, most, if not all, developing countries are predominantly concerned with increasing energy access. Here, we review thirty-four widely used EPMs to investigate their applicability to developing countries and find an absence of consideration of the objectives, challenges, and nuances of the developing context. Key deficiencies arise from the lack of deliberation of the low energy demand resulting from lack of access and availability of supply. Other inadequacies include the lack of consideration of socio-economic nuances such as the prevalence of corruption and resulting cost inflation, the methods for adequately addressing the shortcomings in data quality, availability and adequacy, and the effects of climate change. We argue for further research on characterisation and modelling of suppressed demand, climate change impacts, and socio-political feedback in developing countries, and the development of contextual EPMs
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