Hyper Elliptic Curve Based Certificateless Signcryption Scheme for Secure IIoT Communications

Industrial internet of things (IIoT) is the usage of internet of things (IoT) devices and applications for the purpose of sensing, processing and communicating real-time events in the industrial system to reduce the unnecessary operational cost and enhance manufacturing and other industrial-related processes to attain more profits. However, such IoT based smart industries need internet connectivity and interoperability which makes them susceptible to numerous cyber-attacks due to the scarcity of computational resources of IoT devices and communication over insecure wireless channels. Therefore, this necessitates the design of an efficient security mechanism for IIoT environment. In this paper, we propose a hyperelliptic curve cryptography (HECC) based IIoT Certificateless Signcryption (IIoT-CS) scheme, with the aim of improving security while lowering computational and communication overhead in IIoT environment. HECC with 80-bit smaller key and parameters sizes offers similar security as elliptic curve cryptography (ECC) with 160-bit long key and parameters sizes. We assessed the IIoT-CS scheme security by applying formal and informal security evaluation techniques. We used Real or Random (RoR) model and the widely used automated validation of internet security protocols and applications (AVISPA) simulation tool for formal security analysis and proved that the IIoT-CS scheme provides resistance to various attacks. Our proposed IIoT-CS scheme is relatively less expensive compared to the current state-of-the-art in terms of computational cost and communication overhead. Furthermore, the IIoT-CS scheme is 31.25% and 51.31% more efficient in computational cost and communication overhead, respectively, compared to the most recent protocol.     

A precise measurement of some nonlinear effects and its application to the evaluation of nonlinear elastic constants of quartz and GaPO4

This paper deals with a precise measurement of amplitude frequency and intermodulation effects, and its application to the evaluation of nonlinear elastic constants of quartz and gallium orthophosphate (GaPO/sub 4/). An evaluation is based on the methods used previously concerning determination of the higher-order material constants in the quartz. Using a measurement of the intermodulation products and measurement of drive level dependence of resonant frequency of quartz resonators, we have determined some effective elastic constants of fourth order. The computer-based method of solution of the set of equations gives an access to obtain a number of effective nonlinear stiffnesses of fourth order. The measurements and computer solutions are performed on different Y-cuts resonators, both for quartz and gallium orthophosphate resonators, vibrating in fundamental thickness shear mode. The experimental results are discussed.     

The theoretical strength of fcc crystals under multiaxial loading

Atomistic modeling of a special triaxial loading of six perfect fcc crystals is performed by means of pseudopotential density functional method. The triaxial stress state is simulated as a superposition of axial pressure and transverse biaxial stresses. The transverse stresses are treated as adjustable parameters and their influence on the theoretical compressive strength is evaluated for the 〈1 0 0〉 and the 〈1 1 1〉 crystallographic orientations of the loading axis. The obtained results revealed that the compressive strengths are increasing linear functions of the transverse compressive stresses. On the other hand, the tensile transverse stresses lower the compressive strength. This implies that the compressive strengths of individual crystals approach a zero value when some critical (characteristic) levels of tensile biaxial stresses are reached. These stresses are then considered to be the theoretical tensile biaxial strengths.     

Etching of n-GaN - Important step in device processing

Photo-assisted electrochemical (PEC) and photo-assisted electrodeless (ELPEC) etching of n-doped GaN layers grown on sapphire in a KOH based solution under illumination of Hg arc lamp is demonstrated. Smooth surfaces were obtained for a narrow range of etching conditions. It was found out that this window could be extended by using etching conditions which produced “whiskers”. For ELPEC etching final etched surfaces were much smoother with stirring but showed distinct bar objects. Such objects could be eliminated by chopped irradiation when also the etching rate decreased and smoothing of pyramidal and bar objects in the etched surfaces was observed. This effect is most probably caused by the electron-hole pair recombination suppressed at semiconductor dislocation locations.     

Correlation between Elastic and Electric Properties for Metal Foams: Theory and Experiment

Correlation between Young's modulus and electric conductivity is given in the explicit form for metal foams. Theoretical predictions are compared with the experimental measurements for AlMg1Si0.6 aluminum foams with porosity in the range 70 to 90%. The agreement is better than 10% in all cases.     

Cryogenic pulsed laser deposition of ZnO

The paper deals with the pulsed laser deposition technology and in this special case the substrate was cooled at cryogenic temperature by liquid nitrogen during the deposition process. This approach is proper for growth of highly disordered structures with new physical properties and zinc oxide was applied as experimental example for demonstration. Films were deposited on different substrates: Si (100) and sapphire (0001) and subsequently annealed at different temperatures (200-800 °C). Their properties were investigated by various analytical methods. X-ray diffraction (XRD) proved fully amorphous structure of as-grown ZnO layers which were cooled during the deposition process. Annealing of these amorphous layers changed their properties according to temperature level and annealing time. XRD and scanning electron microscopy (SEM) revealed recrystallized structure. According to the secondary ion mass spectroscopy (SIMS) the layers has homogenous chemical composition along the depth profile with improved homogeneity after annealing.     

Capillary isoelectric focusing and fluorometric detection of proteins and microorganisms dynamically modified by poly(ethylene glycol) pyrenebutanoate

The nonionogenic pyrene-based tenside, poly(ethylene glycol) pyrenebutanoate, was prepared and applied in capillary isoelectric focusing with fluorometric detection. This dye was used here as a buffer additive in capillary isoelectric focusing for a dynamic modification of the sample of proteins and microorganisms. The values of the isoelectric points of the labeled bioanalytes were calculated with use of the fluorescent pI markers and were found comparable with pI of the native compounds. The mixed cultures of proteins and microorganisms, Escherichia coli CCM 3954, Staphylococcus epidermidis CCM 4418, Proteus vulgaris, Enterococcus faecalis CCM 4224, and Stenotrophomonas maltophilia, the strains of the yeast cells, Candida albicans CCM 8180, Candida krusei, Candida parapsilosis, Candida glabrata, Candida tropicalis, and Saccharomyces cerevisiae were reproducibly focused and separated by the suggested technique. Using UV excitation for the on-column fluorometric detection, the minimum detectable amount was down to 10 cells injected on the separation capillary.     

Invariance of perceptual spaces and perceptual separability of stimulus dimensions

This article reports an extension of a paradigm for studying processing of perceptual dimensions. The paradigm is the complete identification task with a feature-complete factorial design (FCFD) of stimuli providing data for multidimensional signal detection analyses. The extension uses blocks of trials with subsets of the FCFD stimulus set, allowing estimation of various d's for inferring perceptual separability (PS) of dimensions and for disambiguating stimulus configurations when PS fails. Results of 4 experiments found the following: PS of arc curvature and line orientation in a discrimination task (Experiment 1), increasing PS failure in detection of horizontal and vertical lines (Experiment 2a), 45 degrees and 135 degrees (Experiment 2b), and 50 degrees and 60 degrees oblique lines (Experiment 2c). In each experiment, corresponding d's remained equivalent across blocks with different stimulus subsets.     

Zur Untersuchung von Ausscheidungsvorgängen in warmfesten Stählen mit rd. 12% Cr bei 500 und 600 °C

Metallographische, elektronenmikroskopische und röntgenographische Untersuchung des Gefügezustandes von sieben verschiedenen warmfesten Stählen mit rd. 0,20% C, rd. 12% Cr und Gehalten an Molybdän bis 2,2%, Vanadin bis 1,11% und Wolfram bis 3,97% nach dem Lösungsglühen bei 1300 °C und Abschrecken in Wasser sowie nach anschließendem Glühen bei 500 und 600 °C während 0,5 bis 5000 h. Gehalt an δ-Ferrit im lösungsgeglühten Zustand. Nachweis der aufeinanderfolgenden Carbidausscheidungsreaktionen im angelassenen Martensit und der Bildung von Lavesphase in δ-Ferrit bei Anwesenheit von Molybdän oder Wolfram. Härteänderung in Abhängigkeit von der Glühdauer. Einfluß der Keimbildungsbedingungen auf den Anstieg der Härte durch Ausscheidung von M₇C₃.     

Major pyrolysis and thermoxidative products from certain polyamides

The nature of the pyrolysis and thermoxidative decomposition products of a number of polyamides was investigated using thermogravimetry, gas chromatography and mass spectrometry. The degree of potential toxic effect has been assessed from qualitative evaluation of the results.