1,732 research outputs found
QoS Constrained Optimal Sink and Relay Placement in Planned Wireless Sensor Networks
We are given a set of sensors at given locations, a set of potential
locations for placing base stations (BSs, or sinks), and another set of
potential locations for placing wireless relay nodes. There is a cost for
placing a BS and a cost for placing a relay. The problem we consider is to
select a set of BS locations, a set of relay locations, and an association of
sensor nodes with the selected BS locations, so that number of hops in the path
from each sensor to its BS is bounded by hmax, and among all such feasible
networks, the cost of the selected network is the minimum. The hop count bound
suffices to ensure a certain probability of the data being delivered to the BS
within a given maximum delay under a light traffic model. We observe that the
problem is NP-Hard, and is hard to even approximate within a constant factor.
For this problem, we propose a polynomial time approximation algorithm
(SmartSelect) based on a relay placement algorithm proposed in our earlier
work, along with a modification of the greedy algorithm for weighted set cover.
We have analyzed the worst case approximation guarantee for this algorithm. We
have also proposed a polynomial time heuristic to improve upon the solution
provided by SmartSelect. Our numerical results demonstrate that the algorithms
provide good quality solutions using very little computation time in various
randomly generated network scenarios
Metallic monoclinic phase in VO induced by electrochemical gating: in-situ Raman study
We report in-situ Raman scattering studies of electrochemically top gated
VO thin film to address metal-insulator transition (MIT) under gating. The
room temperature monoclinic insulating phase goes to metallic state at a gate
voltage of 2.6 V. However, the number of Raman modes do not change with
electrolyte gating showing that the metallic phase is still monoclinic. The
high frequency Raman mode A(7) near 616 cm ascribed to V-O vibration
of bond length 2.06 \AA~ in VO octahedra hardens with increasing gate
voltage and the B(3) mode near 654 cm softens. This shows that the
distortion of the VO octahedra in the monoclinic phase decreases with
gating. The time dependent Raman data at fixed gate voltages of 1 V (for 50
minute, showing enhancement of conductivity by a factor of 50) and 2 V (for 130
minute, showing further increase in conductivity by a factor of 5) show similar
changes in high frequency Raman modes A(7) and B(3) as observed in
gating. This slow change in conductance together with Raman frequency changes
show that the governing mechanism for metalization is more likely to the
diffusion controlled oxygen vacancy formation due to the applied electric
field.Comment: 5 pages, 6 figure
Streaming Video QoE Modeling and Prediction: A Long Short-Term Memory Approach
HTTP based adaptive video streaming has become a popular choice of streaming
due to the reliable transmission and the flexibility offered to adapt to
varying network conditions. However, due to rate adaptation in adaptive
streaming, the quality of the videos at the client keeps varying with time
depending on the end-to-end network conditions. Further, varying network
conditions can lead to the video client running out of playback content
resulting in rebuffering events. These factors affect the user satisfaction and
cause degradation of the user quality of experience (QoE). It is important to
quantify the perceptual QoE of the streaming video users and monitor the same
in a continuous manner so that the QoE degradation can be minimized. However,
the continuous evaluation of QoE is challenging as it is determined by complex
dynamic interactions among the QoE influencing factors. Towards this end, we
present LSTM-QoE, a recurrent neural network based QoE prediction model using a
Long Short-Term Memory (LSTM) network. The LSTM-QoE is a network of cascaded
LSTM blocks to capture the nonlinearities and the complex temporal dependencies
involved in the time varying QoE. Based on an evaluation over several publicly
available continuous QoE databases, we demonstrate that the LSTM-QoE has the
capability to model the QoE dynamics effectively. We compare the proposed model
with the state-of-the-art QoE prediction models and show that it provides
superior performance across these databases. Further, we discuss the state
space perspective for the LSTM-QoE and show the efficacy of the state space
modeling approaches for QoE prediction
SUPPLEMENTATION OF Α-LIPOIC ACID IN DIABETIC PERIPHERAL NEUROPATHY: A PROSPECTIVE OPEN LABEL RANDOMIZED CONTROLLED TRIAL
Abstract Objective: Diabetic peripheral neuropathy is the most common long term complications associated with reduced nerve conduction and blood flow. The present study was designed to investigate the effect of oral supplementation of α-lipoic acid (600 mg/day) on peripheral, sensory and motor nerve conduction and glycaemic control in type 2 diabetes mellitus with peripheral neuropathy. Methods: A total of 20 patients were enrolled in this study, then randomly allocated to two groups control (n=10) and intervention group (n=10). Patients in control group received only oral hypoglycaemic treatment and in intervention group received α-lipoic acid (600 mg/day) oral supplementation along with their oral hypoglycaemic treatment for a period of 3 months. Nerve conduction and glycaemic control were measured at the base line and at the end of 3 months by using specific methods. Results: In intervention group α-lipoic acid supplementation significantly improves 6 of 15 electrophysiological parameters of nerve conduction. Distal latency of peroneal (mean ± SD 5.13 ± 0.52 vs 4.92±0.55; p<0.02), median (mean ± SD 3.66 ± 0.76 vs 3.53±0.63; p<0.03) & ulnar motor nerves (mean ± SD 2.91 ± 0.32 vs 2.82±0.36; p<0.01), and Nerve Conduction Velocity of peroneal (mean ± SD 42.0 ± 3.07 vs 43.4±2.13; p<0.03), median (mean ± SD 51.4 ± 3.31 vs 52.2±3.59; p<0.01) & ulnar motor nerves (mean ± SD 51.0 ± 5.84 vs 52.1±5.46; p<0.03) shows significant improvement. Conclusion: Oral supplementation of α-lipoic acid was found to be effective in improving motor nerve conduction of upper and lower extremities in patients with diabetic peripheral neuropathy
Enhanced hard x-ray emission from microdroplet preplasma
We perform a comparative study of hard x-ray emission from femtosecond laser plasmas in 15 mu m methanol microdroplets and Perspex target. The hard x-ray yield from droplet plasmas is similar or equal to 68 times more than that obtained from solid plasmas at 2x10(15) W cm(-2). A 10 ns prepulse at about 5% of the main pulse appears to be essential for hard x-ray generation from droplets. Hot electron temperature of 36 keV is measured from the droplets at 8x10(14) W cm(-2), whereas a three times higher intensity is needed to obtain similar hot electron temperatures from Perspex plasmas. Particle-in-cell simulations with very long scale-length density profiles support experimental observations. (c) 2006 American Institute of Physics
Assessment of Antisocial Behaviour in the Juveniles
Background: High level of crime, particularly by the people below 18 years, has been a matter of concern for many years. Assessing and preventing the antisocial behaviour in juveniles has become a policy priority.Methods: A cross sectional study was conducted on 52 males less than 18 years in an observation home in Bangalore, India. The data was collected in an interview by filling a semi structured questionnaire. Revised Wisconsin Delinquency Risk Assessment Scale (RWDRAS) was filled up simultaneously and then results were analysed.Results: Majority of the offenders were in the age group 16-18 years. In the majority the cause for antisocial behaviour was unknown followed by the family problems and poverty. The RWDRAS identified 47% of the juveniles with antisocial behaviour as low risk group.Conclusion: The Education, counselling and prevention of poverty are some of the preventive measures of antisocial behaviour. There is a need to develop a better criteria and scale for the diagnosis of antisocial behaviour as the presently used RWDRAS failed in 47% of the juveniles
Tropical storm off Myanmar coast sweeps reefs in Ritchie’s Archipelago, Andaman
The reefs in some islands of Andaman and
Nicobar suffered severe damage following a tropical
storm in the Bay of Bengal off Myanmar coast during
13–17 March 2011. Surveys were conducted at eight
sites in Andaman, of which five were located in the
Ritchie’s Archipelago where maximum wind speeds
of 11 ms-1 was observed; and three around Port Blair
which lay on the leeward side of the storm and had not
experienced wind speeds of more than 9 ms-1. Corals
in the shallow inshore reefs were broken and dislodged
by the thrust of the waves. Significant damage
in the deeper regions and offshore reefs were caused
by the settlement of debris and sand brought down
from the shallower regions. The fragile branching
corals (Acropora sp.) were reduced to rubbles and
the larger boulder corals (Porites sp.) were toppled
over or scarred by falling debris. The reefs on the
windward side and directly in the path of the storm
winds were the worst affected. The investigation exposes
the vulnerability of the reefs in Andaman to the
oceanographic features which generally remain unnoticed
unless the damage is caused to the coastal
habitats
Zero Energy Overwinter Storage of Apple Nursery Plants in trans-Himalayan Ladakh, India
Studies were conducted during 2015 and 2016 to assess the effects of storage conditions on survival of nursery plants in trans-Himalayan Ladakh region. Apple nursery plants raised under warm climatic conditions of Solan (Himachal) were lifted from nurseries in first week of January and stored upto March in cold Ladakh region. Underground cellar-stored plants showed significantly higher plant survival (92 to 94%) than greenhouse-stored plants (37 to 56% survival). Low and constant temperature (-1.5±4.1 to 10.0±1.4ºC) and absence of light inside the cellar were favorable factors for storage of nursery plants. Lower survival rates of greenhouse-stored plants could be attributed to lower and greater fluctuations in temperature (-9.3±1.7to 25.1±1.9ºC) inside the greenhouse. Cellar-stored plants were less subjected to freezing injury as reflected from shoot electrolyte leakage studies. The underground cellar was found effective for overwinter storage of apple nursery plants for 3 to 4 months. The method described is easy and cost-effective, and can be a satisfactory alternative to refrigerated cold storage in trans-Himalayan region with severe winters.
Interaction of mycobacterium tuberculosis rsha and sigh is mediated by salt bridges
10.1371/journal.pone.0043676PLoS ONE78
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