A survey of sensory data boundary estimation,covering and tracking techniques using collaborating sensors

Boundary estimation and tracking have important applications in the areas of environmental monitoring and disaster management. A boundary separates two regions of interest in a phenomenon. It can be visualized as an edge if there is a sharp change in the field value between the two regions or alternatively, as a contour with a field value $f=\tau$ separating two regions with field values $f>\tau$ and $f<\tau$. Examples include contours/boundaries of hazardous concentration in a pollutant spill, frontal boundary of a forest fire, isotherms, isohalines etc. Recent advances in the area of embedded sensor devices and robotics have led to deployments of networks of sensors capable of sensing, computing, communication and mobility. They are used to estimate the boundaries of interest in physical phenomena, monitor or track them over time and also in some cases, mitigate the spatial spread of the phenomena. Since these sensors work autonomously in the environment, minimizing the energy consumed while maximizing the accuracy of estimation or tracking is the main challenge for algorithms for boundary estimation and tracking. Several algorithms with these objectives have been proposed in the literature. In this work, we focus on the algorithms that estimate and cover boundaries found in the sensory data in a field and not the topological boundary of the sensor network per se, which is beyond the scope of this paper.Here, our objective is to provide a comprehensive survey of the algorithms for boundary estimation and tracking by providing a taxonomy based on two broad categories — (i) Boundary estimation and tracking, where the sensors estimate the boundary without physically covering the boundary and (ii) Boundary covering — where the sensors not only predict the location and estimate the entire boundary but also physically cover the boundary by surrounding and bounding it. We further classify the techniques based on (a) sensing capabilities —in situ, range or remote sensing (b) movement capabilities — static or mobile sensors and (c) boundary type — static or dynamic and (d) type of estimation — field estimation where the entire field is sampled to search for contours and localized estimation where sampling is done near the boundary and (e) different types of mobility models in the case of mobile sensors. We believe that such a survey has not been performed before. By capturing and classifying the current state-of-the-art and identifying open research problems, we hope to ignite interest and stimulate efforts towards promising solutions for real-world boundary estimation and tracking problems.     

A Comparative Investigation of Optical and Structural Properties of Cu-Doped CdO-Derived Nanostructures

In this report, we studied various structural and optical properties of pure and copper-doped cadmium oxide (CdO) thin films. Nanostructured Cu-doped CdO films were deposited using sol–gel spin-coating technique. The structural and morphological changes have been observed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and atomic force microscopy (AFM) studies. The optical and electrical properties of the pure and Cu-doped CdO thin films were studied by UV–vis spectroscopy and four-point probe method, respectively. The XRD peaks show the formation of nanocrystalline CdO with cubic face-centered crystal structure. The band gaps of the as deposited films were found in the range of 2.32–2.73 eV, while after doping, it decreases due to structural deformation. The electrical resitivity was found to decrease approximately ～10 in Cu-doped CdO thin films.     

Design and development of long-period grating sensors for temperature monitoring

Long Period Gratings (LPGs) have been developed using carbon dioxide laser in a standard optical fibre. LPGs with a periodicity of 600 μm and grating length of 24 mm have been inscribed on standard single mode fibre. Such gratings have been used in designing temperature sensors and temperature is monitored up to 80°C. The sensitivity of such type of sensor is 0·06 nm/°C where as for standard Fibre Bragg Grating (FBG) it is 0·011 nm/°C. The LPG performance is also evaluated after γ-ray irradiation for total dose of 5 KGy and has not shown any effect on transmission spectrum.     

Performance measurements from LYSO scintillators coupled to a CMOS position sensitive SSPM detector

We have designed a 5×5 mm² position sensitive solid-state photomultiplier (PS-SSPM) using a complementary metal-oxide-semiconductor (CMOS) process that provides imaging capability on the micro-pixel level. The PS-SSPM has 11,664 micro-pixels total, with each having an active area and micro-pixel pitch of 30×30 μm² and 44.3 μm, respectively. The PS-SSPM was then examined for its performance characteristics such as its energy and spatial resolution, and LYSO scintillator array imaging capabilities. When coupled to 5×5×3 mm³ LYSO, the energy resolution at 511 keV (²²Na) was measured as a function of bias, and corrected for the PS-SSPM non-linear output. The resolution is 14% (FWHM) at 511 keV with 30 V bias. The LYSO coincidence timing resolution was 9.4 ns (FWHM) at 511 keV. Spatial resolution studies were conducted using a focused (∼30 μm beam spot diameter) pulsed 635 nm diode laser. Scintillator array imaging studies were conducted at 511 keV using a 6×6 LYSO array, having 500 μm pixels (530 μm pitch) and 5 mm tall.     

Erbium-Ion-Doped Tellurite Glass Fibers and Waveguides—Devices and Future Prospective: Part II

Following on from Part I of this review article that focuses on the suitability of Er³⁺-doped tellurium oxide glass for optical amplification in fiber, this Part II article describes how the fiber gain data were then employed to engineer amplification in waveguides, which can be integrated with semiconductor pump sources. The gain characteristics and bandwidth of a phosphate modified tellurite waveguide formed on a GaAs substrate are discussed. The limiting structural compatibility of Er³⁺-doped tellurite glass with polydimethylsiloxane polymer for active–passive integration is overcome by adopting a nanoscale super-lattice approach for waveguide engineering.     

Covalent Complex of DNA and Bacterial Topoisomerase: Implications in Antibacterial Drug Development

A topoisomerase-DNA transient covalent complex can be a druggable target for novel topoisomerase poison inhibitors that represent a new class of antibacterial or anticancer drugs. Herein, we have investigated molecular features of the functionally important Escherichia coli topoisomerase I (EctopoI)-DNA covalent complex (EctopoIcc) for molecular simulations, which is very useful in the development of new antibacterial drugs. To demonstrate the usefulness of our approach, we used a model small molecule (SM), NSC76027, obtained from virtual screening. We examined the direct binding of NSC76027 to EctopoI as well as inhibition of EctopoI relaxation activity of this SM via experimental techniques. We then performed molecular dynamics (MD) simulations to investigate the dynamics and stability of EctopoIcc and EctopoI-NSC76027-DNA ternary complex. Our simulation results show that NSC76027 forms a stable ternary complex with EctopoIcc. EctopoI investigated here also serves as a model system for investigating a complex of topoisomerase and DNA in which DNA is covalently attached to the protein.     

A novel node authentication protocol connected with ECC for heterogeneous network

Wireless Networks - Unlike regular wireless networks like Mobile Ad hoc NETworks (MANET) can be exploited instinctively devoid of necessitating any centralized administration or available network...     

Detection of multiple virulence-associated genes in Listeria monocytogenes isolated from bovine mastitis cases

Clinical samples (n=725) were collected from bovines (n=243) which were positive for mastitis using the California mastitis test (CMT) and somatic cell count (SCC). The clinical samples comprising blood (n=239), milk (n=243), and faecal swabs (n=243) were examined for the presence of pathogenic Listeria spp. Isolation of the pathogen was done using selective enrichment in University of Vermont Medium and plating onto Dominguez-Rodriguez isolation agar. Confirmation of the isolates was based on biochemical tests and Christie, Atkins, Munch-Petersen (CAMP) test followed by pathogenicity testing. Pathogenicity of the isolates was tested by phosphatidylinositol-specific phospholipase C (PI-PLC) assay as well as in vivo tests namely, chick embryo and mice inoculation tests. The isolates were subjected to PCR assay for five virulence-associated genes, plcA, prfA, hlyA, actA and iap. Listeria spp. were isolated from 12 (1.66%) samples. Of these 4 (0.55%) and 1 (0.14%) were confirmed as Listeria monocytogenes and Listeria ivanovii, respectively. L. monocytogenes and L. ivanovii were recovered from milk samples (2) and faecal (3) of mastitic cattle (3) and buffaloes (2). L. monocytogenes recovered from the milk of mastitic cattle and L. ivanovii from the faecal swab of buffalo turned out to be pathogenic. However, the remaining three hemolytic isolates exhibiting positive CAMP test turned out to be negative in PI-PLC assay, chick embryo and mice inoculation. L. monocytogenes and L. ivanovii isolates characterized as pathogenic by PI-PLC assay and in vivo pathogenicity tests were found to possess all the five virulence-associated genes and three genes, plcA, prfA and actA respectively. The remaining three hemolytic but non-pathogenic L. monocytogenes isolates were negative for plcA by PCR. It seems that the plcA gene and its expression (in the PI-PLC assay) have an important role as virulence determinants in pathogenic Listeria spp. In conclusion, the PI-PLC assay and virulence genes targeted PCR (plcA, prfA and hlyA genes for L. monocytogenes and plcA, prfA and actA genes for L. ivanovii) hold a good promise as rapid and reliable in vitro alternatives to in vivo pathogenicity tests.     

Investigation and mapping of toxic fumes produced by detonation of ANFO explosives in underground space

Post-blast fumes are hazardous and known to cause severe health related issues of workers. Further, these harmful gases have a significant impact on the surrounding environment. Thus, it is imperative to have an in-depth understanding of the real time detonation fume generation in underground space to avoid hazardous health risk of the worker. In this context, the mapping of toxic fume concentrations generated by the detonation of ANFO explosives in the actual field is a fascinating area of research that has a great environmental impact. This article examined the real-time analysis of toxic fumes generated by ammonium nitrate fuel oil (ANFO) explosives at various locations of a metalliferous underground mine. Furthermore, detonation parameters of various ANFO explosive compositions were also studied at the mining site. On-site blasting studies were performed with ANFO explosives, and post-detonation fume measurements enabled us to map the CO and NO_x concentrations in underground spaces. Toxic fumes like CO and NO_x were analyzed before and after each blasting operation at different intervals, and found within the allowed limit as per the Directorate General of Mines Safety guidelines. Additionally, an empirical correlation has been established to evaluate the maximum detonation velocity based on the alteration of ammonium nitrate and fuel oil composition.