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51.
Ahmed Syed Thouheed Sandhya M. Sankar Sharmila 《Wireless Personal Communications》2020,112(2):1061-1077
Wireless Personal Communications - Tele-Medical data communication via general purpose networking protocols and techniques are major set-back under low line channels and adequate resources such as... 相似文献
52.
Security is the major issue in wireless sensor networks and many defence mechanisms have been developed to secure the network from these alarming attacks by detecting the malicious nodes which hinder the performance of the network. Sybil attack can make the network vulnerable. Sybil attack means a node which illegitimately claims multiple identities. This attack threatens wireless sensor network in routing, voting system, fair resource allocation, data aggregation and misbehaviour detection. Hence, the research is carried out to prevent the Sybil attack and improve the network performance. The node ID-based scheme is proposed, where the detection is based on node registration, consisting of two phases and the assignment of ID to the node is done dynamically. The ID's corresponding to the nodes registered is at the base station and the node active time is monitored, any abnormalities in the above phases confirm the presence of Sybil nodes in the network. The scheme is simulated using NS2. The energy consumed for this algorithm is 2.3?J. The proposed detection scheme is analysed based on the network's PDR and found that the throughput has improved, which prove that this scheme may be used in the environment where security is needed. 相似文献
53.
Satellite images are often corrupted by noise in the acquisition and transmission process. While removing noise from the image by attenuating the high frequency image components, it removes some important details as well. In order to improve the visual appearance and retain the useful information of the images, an effective denoising technique is required to reduce the noise level. For denoising, many researches exploit the directional correlation in either spatial or frequency domain. However, the orientation estimation for directional correlation becomes inefficient and error prone in noised circumstances. This paper proposes a new hybrid directional lifting (HDL) technique for image denoising that involves pixel classification and orientation estimation, along with adding small amount of noise, in order to improve the performance efficiency of the technique. Experimental results show that the HDL technique improves both peak signal to noise ratio and visual quality of images with rich textures. 相似文献
54.
Abstract The possibility of occurrence of the coherent optical transient effect known as optical nutation has been analytically established in the semiconductor quantum well (QW) structure, namely GaAs/GaxA11?xAs most extensively used in optical electronics. Ultra-short-pulse low-intensity band-to-band excitation of electrons to the 1s Wannier-Mott exciton state of the crystal has been considered to play an important role in the coherent radiation—QW interaction. Numerical estimations of the complex optical susceptibility and the transmitted intensity under the transient regime reveal ringing behaviour confirming the occurrence of optical nutation in III-V semiconducting QW structures. 相似文献
55.
Nano containers with a shell possessing controlled release properties can be used to fabricate a new family of active coatings that can respond quickly to change the environment/integrity of the coatings. The release of corrosion inhibitors encapsulated within nano containers can prevent further corrosion. The structural evolutions and morphological characteristics of nano particles are investigated using XRD, SEM, FT-IR and AFM. The author reports an in situ encapsulation method demonstrating over an order of magnitude size reduction for the preparation of urea-formaldehyde capsules filled with a healing agent, linseed oil and corrosion inhibitors. Capsules with diameters as small as 30–40 μm are achieved using stirring techniques. Cracks in paint film were successfully healed when linseed oil and nanoparticles was released from microcapsules ruptured under stimulated mechanical action. Further linseed oil healed area was found to prevent corrosion of the substrate. 相似文献
56.
Sharmila Savarimuthu Maryam Purvis Martin Purvis Bastin Tony Roy Savarimuthu 《Minds and Machines》2013,23(4):419-441
The objective of this work is to demonstrate how cooperative sharers and uncooperative free riders can be placed in different groups of an electronic society in a decentralised manner. We have simulated an agent-based open and decentralised P2P system which self-organises itself into different groups to avoid cooperative sharers being exploited by uncooperative free riders. This approach encourages sharers to move to better groups and restricts free riders into those groups of sharers without needing centralised control. Our approach is suitable for current P2P systems that are open and distributed. Gossip is used as a social mechanism for information sharing which facilitates the formation of groups. Using multi-agent based simulations we demonstrate how the adaptive behaviour of agents lead to self-organisation. We have tested with varying the gossip level and checked its impact in the system’s behaviour. We have also investigated the impact of false gossip in this system where gossip is the medium for information sharing which leads to self-organisation. 相似文献
57.
Ionic Double Layers at the Surface of Magnesium-Doped Aluminum Oxide: Effect on Segregation Properties 总被引:1,自引:0,他引:1
A model involving ionic double layers at the surface has been constructed for magnesia-doped sapphire based on earlier models which were developed for cubic halides. The model takes into account the presence of electrostatic potentials, isolated point defects, defect complexes, and special surface sites which can act as sources and sinks for ions. Equations have been set up for the various defect concentrations, and Poisson's equation has been solved numerically to give depth profiles for defects and corresponding electric fields. The calculations suggest that Mg2+ ions can segregate both to the free surface and to the space charge region. The effective (or Langmuir) enthalpy of segregation depends not only on the actual binding energies of the dopant ion, but also on other parameters such as the density of special surface sites. Over the temperature range studied, the variation of the calculated surface magnesium concentration with temperature is found to be approximately Arrhenius in nature, as was observed in segregation experiments. 相似文献
58.
Fibrinolytic enzyme producing microorganisms with high fibrin specificity were screened, including lactic acid bacteria from fermented soybean foods of North-East India. A total of 5 isolates, including Lactococcus lactis (FS1), Vagococcus lutrae (FS6), Vagococcus fluvialis (FS7), Weissella thailandensis (FS8), and Bacillus methylotrophicus (FS19) were found to hydrolyze fibrin directly on a plasminogen-free fibrin plate. Hydrolysis of fibrin was stronger with crude enzymes than with plasmin, indicating high fibrin specificity. The molecular weights of these enzymes, as determined by SDS-PAGE, ranged from 35 to 116 kDa. 相似文献
59.
Present study was undertaken to determine the level of PAH contamination due to jet turbine exhaust in the peripheral soil of the International Airport in Delhi, India. Densely populated residential areas surrounding the airport come directly under both the landing and take-off flight paths. Twelve priority polycyclic aromatic hydrocarbons (PAHs) were analyzed in the <2 mm surface soil fraction. Identification and quantification of PAHs was done by high performance liquid chromatography (HPLC). The sum of 12 PAHs ranged from 2.39 microg g(-1) to 7.53 microg g(-1) with a mean concentration of 4.43+/-1.45 microg g(-1). PAH levels observed in the present study were found to be higher as compared to most of the literature values. Among the three sampling sites selected around the International Airport, the site near landing point revealed maximum concentration of PAHs, while minimum concentration was observed at the site near take-off point. Predominance of pyrene was observed in the airport soil. Factor analysis and isomer pair ratios suggest pyrogenic origin of PAHs in the study area. 相似文献
60.
Laura Soriano-Romaní Fayaz A. Mir Niharika Singh Ian Chin Ali Hafezi-Moghadam Sharmila Masli 《International journal of molecular sciences》2022,23(10)
To address the conflicting role of thrombospondin (TSP)-1 reported in acute and chronic pathologies, this study investigated the role of TSP-1 in regulating leukocyte recruitment and regulation of VCAM-1 expression using mouse models of uveitis. The spontaneously increased VCAM-1 expression and leukocyte adhesion in retinas of TSP-1-deficient mice suggested a TSP-1-mediated regulation of VCAM-1 expression. In a chronic uveitis model, induced by immunizing wild-type mice with specific interphotoreceptor retinoid-binding protein (IRBP) peptide, topically applied TSP-1-derived CD47-binding peptide significantly reduced the clinical disease course and retinal leukocyte adhesion as compared to the control peptide-treated group. In contrast, in LPS-mediated acute uveitis, TSP-1 deficiency significantly reduced the retinal leukocyte adhesion. The results of our in vitro study, using vascular endothelial cell (EC) cultures, demonstrate that unlike TNF-α, VCAM-1 expression induced by IL-17 is associated with a reduced expression of endogenous TSP-1. Such reduced endogenous TSP-1 expression in IL-17-stimulated ECs helps limit the CD36-mediated increased VCAM-1 expression, while favoring CD47-mediated inhibition of VCAM-1 expression and leukocyte adhesion. Thus, our study identifies TSP-1:CD47 interaction as a molecular pathway that modulates IL-17-mediated VCAM-1 expression, contributing to its anti-inflammatory effect in chronic inflammatory conditions. 相似文献