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Event-Triggered Second-Moment Stabilization of Linear Systems Under Packet Drops
No full textThis paper deals with the stabilization of linear systems with process noise under packet drops between the sensor and the controller. Our aim is to ensure exponential convergence of the second moment of the plant state to a given bound in finite time. Motivated by considerations about the efficient use of the available resources, we adopt an event-triggering approach to design the transmission policy. In our design, the sensor's decision to transmit or not is based on an online evaluation of whether the control objective may be violated in the future. The resulting event-triggering policy is hence specifically tailored to the control objective. We formally establish that the proposed event-triggering policy meets the desired objective and quantify its efficiency by providing an upper bound on the fraction of expected number of transmissions in an infinite time interval. Simulations for scalar and vector systems illustrate the results
A Comprehensive Life-Cycle Assessment of Locally Oriented Small-Scale Toy Industries: A Study of traditional Channapatna Toys as Against low-cost PVC (Poly-Vinyl Chloride) Toys made in China
No full textToys play an elemental role in the mental, physical, social and emotional development of children. These toys are available in a variety of materials to choose from e.g.: Plastic, wood, cloth etc. Channapatna toys are softwood toys locally manufactured in Channapatna town, Bangalore rural-district in India. These toys are usually made from softwood obtained from Wrightia tinctoria, which are then lacquered and sold. The aim of this paper is to study the environmental impacts of Channapatna toys vis-a-vis Plastic toys - specifically Poly-vinyl Chloride (PVC); by Life-cycle assessment (LCA) ou Simapro 8.4. This comparative study revealed that locally-made Channapatna toys were less toxic, consumed less energy and had minimum environmental impacts as compared to readily available PVC toys. Additionally, solutions were proposed to promote such locally-oriented small-scale toy industries; which not only safeguard the future of children but are also environmentally sustainable and help preserve the traditional craft and cultural heritage. (C) 2018 The Authors. Published by Elsevier B.V
Relative occurrences and difference of extrema for detection of transitions between broad phonetic classes
No full textDetection of transitions between broad phonetic classes in a speech signal has applications such as landmark detection and segmentation. The proposed hierarchical method detects silence to non-silence transitions, sonorant to non-sonorant transitions and vice-versa. The subset of the extrema (minimum or maximum amplitude samples) above a threshold, occurring between every pair of successive zero-crossings, is selected from each frame of the bandpass-filtered speech signal. Locations of the first and the last extrema lie on either side far away from the mid-point (reference) of a frame, if the speech signal belongs to a non-transition segment; else, one of these locations lies within a few samples from the reference, indicating a transition frame. The transitions are detected from the entire TIMIT database for clean speech and 93.6% of them are within a tolerance of 20 ms from the phone boundaries. Sonorant, unvoiced non-sonorant and silence classes and their respective onsets are detected with an accuracy of about 83.5% for the same tolerance with respect to the labelled TIMIT database as reference. The results are as good as, and in some aspects better than, the state-of-the-art methods for similar tasks. The proposed method is also tested on the test set of the TIMIT database for robustness with respect to white, babble and Schroeder noise, and about 90% of the transitions are detected within a tolerance of 20 ms at the signal to noise ratio of 5 dB. On NTIMIT database, 62.7% of the transitions are detected, and 63.5% of the sonorant onsets, within 20 ms tolerance
Buried channel normally-off AIGaN/GaN MOS-HEMT with a p-n junction in GaN buffer
No full textA buried channel normally-off AlGaN/GaN MOS-HEMT with gate recess etching is reported. The buried channel operation is achieved by in situ doping of GaN to introduce a p-n junction in the GaN buffer. The fabricated buried channel MOS-HEMT with 12.5 nm atomic layer deposition (ALD) Al2O3 gate dielectric featured a threshold voltage of 1.3 V with a drain saturation current of 287 mA mm(-1) for a device with 3.5 mu m long gate length and 11 mu m sourcedrain spacing. The field effect mobility improved from 25 cm(2)/Vs for a reference device to 142 cm(2)/Vs for the buried channel device. Due to the presence of the p-n junction depletion region in the GaN buffer, the leakage in the off state decreased by about 4 orders of magnitude (4 nA mm(-1) compared to 76 uA mm(-1) for the reference device). The buried channel device also gives better breakdown characteristics, with a breakdown voltage of 158 V compared to 98 V for the reference device
TfOH catalyzed synthesis of 1-substituted tetrahydrocarbazoles
No full textSynthesis of 1-substituted tetrahydrocarbazole is accomplished by TfOH catalyzed reaction of 3-substituted indoles tethered with secondary and tertiary alcohols. The reaction was generalized for a variety of substrates and was extended to the synthesis of 2,3,3a,6-tetrahydro-1H-pyrido3,2,1-jk]carbazole and carbazoles. (C) 2018 Elsevier Ltd. All rights reserved
A New Approach to Compute the Porosity and Surface Roughness of Porous Coated Capillary-Assisted Low Pressure Evaporators
No full textThe fundamental characteristics of metal coatings that influence heat transfer are porosity and surface roughness. It is a challenge to analyze the porosity and surface roughness due to the inadequate amount of copper per coated area. In this study, a new approach to non-invasively determine the porosity of metal films utilizing a helium pycnometer and computed micro-tomography (CMT) is presented. Furthermore, a telescope-goniometer is used to measure the surface roughness. Experiments are conducted on four varieties of thin film samples coated with copper powder using wire flame and plasma thermal spray coating methods. The porosities of the thin films were determined to be between 39 and 43%. The thermal spray coating increased the hydrophobicity of the surface and the plasma coating created super-hydrophobic surfaces. The new approach establishes that the porosity of thin films can be non-invasively determined and may also be applied to a wide variety of coated surfaces
Probing the effect of solvation on photoexcited 2-(2 `-hydroxyphenyl)benzothiazole via ultrafast Raman loss spectroscopic studies
No full text2-(2 `-Hydroxyphenyl)benzothiazole (HBT) molecule is known to exhibit efficient excited state intramolecular proton transfer. As a consequence, it shows fluorescence with a large Stokes shift (similar to 10 000 cm(-1)) in non-polar solvents. However, fluorescence in polar solvents has a dual-band which corresponds to the emission from both the enol* and the keto* forms. Also, the excited state lifetime significantly varies with the solvent polarity. Recently, Mohammed et al. J. Phys. Chem. A 115, 7550 (2011)] have shown that the excited state of HBT in acetonitrile (ACN) relaxes back to its ground electronic state through two competitive decay pathways, i.e., intramolecular proton transfer and intramolecular twisting between hydroxyphenyl and benzothiazole units in contrast to its behavior when it is in tetrachloroethene, a non-polar solvent. Here, by following the time-evolution of vibrational features of excited state HBT in ACN through ultrafast Raman loss spectroscopy, we demonstrate a direct evidence for the involvement of torsional motion leading to an ultrashort lifetime of HBT. The time evolution of the C-7-N vibrational frequency exhibited a red-shift in its peak position, clearly indicating the evolution of the initially planar cis-keto* form to the more twisted keto* form. Density functional theory calculations also well corroborate the experimental findings. Furthermore, wavepacket analysis of this mode reveals a strong correlation with the torsional motion in ACN. Published by AIP Publishing
On the relationship between the Pacific Decadal Oscillation and monsoon depressions over the Bay of Bengal
No full textThis study investigates the relationship between inter-decadal variation in the number of monsoon depressions (MDs) over the Bay of Bengal (BoB) and the Pacific Decadal Oscillation (PDO). It is shown that there is an out-of-phase variation in the number of MDs over the BoB and the PDO, except during 1927-1945. Quantitative estimates of the relative contributions of individual environmental parameters show that the variation in the mid-tropospheric relative humidity over the BoB is the primary reason for the observed variation in the number of MDs. It is further postulated that the variation in the sea surface temperature in the western equatorial Indian Ocean associated with the PDO could be one of the reasons for the changes in the moisture advection over to the BoB and hence the variation in the number of MDs in inter-decadal timescale
Heterogeneity in pneumolysin expression governs the fate of Streptococcus pneumoniae during blood-brain barrier trafficking
No full textOutcome of host-pathogen encounter is determined by the complex interplay between protective bacterial and host defense strategies. This complexity further amplifies with the existence of cell-to-cell phenotypic heterogeneity in pathogens which remains largely unexplored. In this study, we illustrated that heterogeneous expression of pneumolysin (Ply), a pore-forming toxin of the meningeal pathogen, S. pneumoniae (SPN) gives rise to stochastically different bacterial subpopulations with variable fate during passage across blood-brain barrier (BBB). We demonstrate that Ply mediated damage to pneumococcus containing vacuolar (PCV) membrane leads to recruitment of cytosolic ``eat-me'' signals, galectin-8 and ubiquitin, targeting SPN for autophagic clearance. However, a majority of high Ply producing subset extensively damages autophagosomes leading to pneumococcal escape into cytosol and efficient clearance by host ubiquitination machinery. Interestingly, a low Ply producing subset halts autophagosomal maturation and evades all intracellular defense mechanisms, promoting its prolonged survival and successful transcytosis across BBB, both in vitro and in vivo. Ply therefore acts as both, sword and shield implying that its smart regulation ensures optimal disease manifestation. Our elucidation of heterogeneity in Ply expression leading to disparate infection outcomes attempts to resolve the dubious role of Ply in pneumococcal pathogenesis
Packing and Covering with Non-Piercing Regions
No full textIn this paper, we design the first polynomial time approximation schemes for the Set Cover and Dominating Set problems when the underlying sets are non-piercing regions (which include pseudodisks). Earlier, PTASs were known only in the setting where the regions were disks. These techniques relied heavily on the circularity of the disks. We develop new techniques to show that a simple local search algorithm yields a PTAS for the problems on non-piercing regions. We then consider the Capacitated Region Packing problem. Here, the input consists of a set of points with capacities, and a set of regions. The objective is to pick a maximum cardinality subset of regions so that no point is covered by more regions than its capacity. We show that this problem admits a PTAS when the regions are k-admissible regions (pseudodisks are 2-admissible), and the capacities are bounded by some constant. Our result settles a conjecture of Har-Peled from 2014 in the affirmative. The conjecture was for a weaker version of the problem, namely when the regions are pseudodisks, the capacities are uniform, and the point set consists of all points in the plane. Finally, we consider the Capacitated Point Packing problem. In this setting, the regions have capacities, and our objective is to find a maximum cardinality subset of points such that no region has more points than its capacity. We show that this problem admits a PTAS when the capacity is unity. This extends a result of Ene et al. from 2012