A survey of security and privacy issues in the Internet of Things from the layered context

© 2020 John Wiley & Sons, Ltd. Internet of Things (IoT) is a novel paradigm, which not only facilitates a large number of devices to be ubiquitously connected over the Internet but also provides a mechanism to remotely control these devices. The IoT is pervasive and is almost an integral part of our daily life. These connected devices often obtain user's personal data and store it online. The security of collected data is a big concern in recent times. As devices are becoming increasingly connected, privacy and security issues become more and more critical and these need to be addressed on an urgent basis. IoT implementations and devices are eminently prone to threats that could compromise the security and privacy of the consumers, which, in turn, could influence its practical deployment. In recent past, some research has been carried out to secure IoT devices with an intention to alleviate the security concerns of users. There have been research on blockchain technologies to tackle the privacy and security issues of the collected data in IoT. The purpose of this paper is to highlight the security and privacy issues in IoT systems. To this effect, the paper examines the security issues at each layer in the IoT protocol stack, identifies the under-lying challenges and key security requirements and provides a brief overview of existing security solutions to safeguard the IoT from the layered context

The survey on aquaculture capacity of Ghar-Khatlo dam reservoir in Zanjan province

Qhar-khetlu dam reservoir is in the central part of Ijrud city of Zanjan province with a reservoir volume of 500000 and a water volume of 900000 cubic meters, covering an area of 6 hectares and containing 3500 hectares of the watershed in order to control seasonal floods, drinking water in the village, strengthening the aquifers of the area and As a water supply in the dry seasons, 120 hectares of agricultural land was planted for irrigation.Study of this water source with the aim of measuring biological and non-biological factors, determination of aquaculture production and Fish release capacity and fishing capacity for optimal use of fishery management in Zanjan province was done in 2006.The results of hydrochemical analysis of the water of Qharkhetlu dam reservoir showed that the minimum and maximum temperature of water ranged from 4.5 to 26 ° C, the pH of the water was 4.7 to 8.8, the dissolved oxygen was 7.7 to 12.2 mg, the total water hardness fluctuation was 154 194 mg/L and electrical conductivity of 272 to 390 micrometers per square centimeter, the water transparency was 25 to 380 centimeters.In this study, six phytoplankton classes with 31 genera and 3 classes of zooplankton with 14 genera were obtained. The abundance of phytoplanktons was counted from 150,000 to 206,000 per liter, and the average chlorophyll a, 1.10 micrograms, was estimated. The frequency of zooplanktons were 32 to 132 per liter, as well as the mean of 544 per square meter of macrobenthos.By comparing of the physical, chemical and biological factors and also the results of previous studies of this water source, the conditions for the introduction of warm water and cold water fishes including silver carp, big head carp, rainbow trout out and native fishes including species of Barbus and Capoeta genera are suitable. Estimation of Qhar-khetlu dam reservoir production is 80 kg/ha and its production capacity is 484 kg per year

Original article title: "Comparison of therapeutic efficacy of topical corticosteroid and oral zinc sulfate-topical corticosteroid combination in the treatment of vitiligo patients: a clinical trial"

<p>Abstract</p> <p>Background</p> <p>Vitiligo is the most prevalent pigmentary disorder which occurs worldwide, with an incidence rate between 0.1-4 percent. It is anticipated that the discovery of biological pathways of vitiligo pathogenesis will provide novel therapeutic and prophylactic targets for future approaches to the treatment and prevention of vitiligo. The purposes of this study were evaluating the efficacy of supplemental zinc on the treatment of vitiligo.</p> <p>Methods</p> <p>This randomized clinical trial was conducted for a period of one year. Thirty five patients among 86 participants were eligible to entrance to the study. The patients in two equal randomized groups took topical corticosteroid and combination of oral zinc sulfate-topical corticosteroid.</p> <p>Results</p> <p>The mean of responses in the corticosteroid group and the zinc sulfate-corticosteroid combination group were 21.43% and 24.7%, respectively.</p> <p>Conclusion</p> <p>Although, the response to corticosteroid plus zinc sulfate was more than corticosteroid, there was no statistically significant difference between them. It appeared that more robust long-term randomized controlled trials on more patients, maybe with higher doses of zinc sulfate, are needed to fully establish the efficacy of oral zinc in management of vitiligo.</p> <p>Trial Registration</p> <p>chiCTRTRC10000930</p

Study of Golabar dam reservoir in Zanjan province (Zanjan Province)

The limnological study of the Golabar dam showed that in the Glabar dam inspite of bing its early establishment due to high nutrient and organic matter is located in eutrophic stage. the pH as well as bicarbonate levels shows that buffering capacity of the lake is high and the value of inorganic and organic matter measured are not considered as limiting factor for warme and cold water aquaculture. In the plankton survey 44 species of phytoplankton and 25 species of zooplankton were identified. Cyclotella , Nitzschia, Synedra and Trachelomona from phytoplankton and Polyarthera , Keratella , Filinia , Pompholyx from zooplankton were the dominant spicies.the Bacillariophyta from phytoplankton with 76.5 percent and Rotatoria zooplankton to with 76.2 percent considered the highest abundant . The average frequency of phytoplankton and zooplankton were 5*106 and 723 individual per litter. The Shironomide and Tobificide were the only two bentic group were identified in reservoir wehre their mean frequced were 293.75 and 224.30 respectively. The average biomass of bentic organism were 1.44±0.97 gr/m2.In the survey 12 species of fishes were identified. The potential natural production have been estimated to be 2.8 to 15.5 kg for bentivorous fish and varied from 53 to 175 kg /hec for plankton consumer fishes .The low temperature in several months as well as ice covered of the lake surface in particular in the months of duty and Bahman are the limiting factor of either warm or cold water fish production

Behaviour of cylindrical and doubly-curved shell roofs under earthquake

There are indications that thin shells are once again becoming a popular option for roofs covering large column free spaces. Relative to other structural forms there is relatively little analysis of their dynamic response. Especially in seismically active regions, this paucity of analyses could be of considerable significance. This research reports a verification study based upon two independent methods: a finite element solution and a newly developed analytical method. For typical cylindrical shell roofs these methods have been used to determine the spectra of natural vibration modes, displacements, accelerations and stress resultants of the shell under the action of the vertical motions of a selected earthquake. The comparisons showed the FE and analytical results to be in practically excellent agreement. The study of the numbers of modes required for accurate prediction of displacement, acceleration, and stress response for a specific geometry of shell showed that unlike ordinary buildings, in roof shells there is a need to include substantial number of modes for a converged result. Of the limited past investigations on how thin shell roofs respond to earthquakes, attention has been restricted to consideration of just the out-of-plane modes, with the contributions from the in-plane modes usually neglected. The importance of the inclusion of in-plane modes for a cylindrical shell subject to the vertical component of a selected earthquake loading showed that these modes can potentially have a major impact on the predicted levels of in-plane deformation and the associated membrane stresses, and therefore depending on the type of earthquake should be included for reliable estimates of earthquake response. The assessment of the relative importance of the horizontal and vertical components of earthquakes showed that vertical components result in higher accelerations and stresses compared to the horizontal components. In the past investigations of how thin shell roofs respond to earthquakes, attention has been largely restricted to linear analysis, with contributions from pre-loading usually neglected. The independent approaches using finite element solution and a newly developed analytical method indicate that inclusion of self-weight and additional superimposed loading can significantly reduce the predicted natural frequencies. Consequently inclusion of pre-loading is shown to have a major influence on the levels of deformations and the associated membrane stresses. It is concluded that performing a modal analysis in which the effects of pre-loading are ignored could lead to serious underestimation of responses for large roof shells under earthquake loading. Furthermore a nonlinear snap buckling analysis showed that the snap buckling loads are much lower than the classical critical loads in cylindrical roof shell, which suggest a need for a complete nonlinear analysis for the cases of shell with pre-loading close to snap buckling loads. The final section of the present research compares the frequencies and linear responses of a doubly curved shell with a cylindrical shell. The results showed that the frequencies of a doubly curved shell are higher than a cylindrical shell. The increase in the natural frequencies resulted in much lower displacements and stress resultant responses in the doubly curved shell

Effect of pre-loading on response of cylindrical roof shells under earthquake loading

Of the limited past investigations of how thin shell roofs respond to earthquakes, attention has been largely restricted to linear analysis, with contributions from pre-loading usually neglected. The present paper first analyses the effects of pre-loading on the natural vibration spectra using a newly developed analytical method. Results of this investigation indicate that inclusion of self weight and additional superimposed loading can significantly reduce the predicted natural frequencies. Parameter studies illustrate the importance of the inclusion of pre-loading on the maximum isplacement and stress responses, of a set of cylindrical roof shells having different geometries, when subject to the vertical motions of a typical earthquake. Inclusion of pre-loading is shown to have possibly major influences on the levels of deformations and the associated membrane and bending stresses. It is concluded that performing a modal analysis in which the effects of pre-loading are ignored could lead to serious underestimation of responses for large roof shells subject to earthquake loading

Structural evaluation and mechanical properties of AZ31/SiC nano-composite produced by friction stir welding process at various welding speeds

A metal matrix composite made of AZ31 containing SiC nano-particles was successfully produced by friction stir welding (FSW), and the effect of processing parameters such as rotational and transversal speeds on the microstructure (grain size) and mechanical properties (tensile and hardness tests) were investigated. Prior to friction stir welding, nano-sized SiC particles were incorporated into the joint line and then different rotational (600, 800 and 1000¿r/min) and transversal speeds (25, 75, 125 and 175¿mm/min) were tested. The results indicated that the grain size of the matrix and SiC nano-particles are two key parameters controlling different characteristics of the developed composite. Both parameters, in turns, are dependent on the heat generated during the FSW process. The increase of rotational speed and decrease of transversal speed result in high amount of heat and homogeneous distribution of SiC nano-particles. The former leads to grain growth and decrease of strength and hardness, while the latter causes grain refinement and increases of strength and hardness. Accordingly, the heat input has opposite effects on matrix grain growth and homogeneous distribution of particles. Therefore, optimum values of rotational and transversal speeds were found (800¿r/min and 75¿mm/min) to produce the best microstructure and mechanical properties.Preprin

Structural evaluation and mechanical properties of AZ31/SiC nano-composite produced by friction stir welding process at various welding speeds

A metal matrix composite made of AZ31 containing SiC nano-particles was successfully produced by friction stir welding (FSW), and the effect of processing parameters such as rotational and transversal speeds on the microstructure (grain size) and mechanical properties (tensile and hardness tests) were investigated. Prior to friction stir welding, nano-sized SiC particles were incorporated into the joint line and then different rotational (600, 800 and 1000¿r/min) and transversal speeds (25, 75, 125 and 175¿mm/min) were tested. The results indicated that the grain size of the matrix and SiC nano-particles are two key parameters controlling different characteristics of the developed composite. Both parameters, in turns, are dependent on the heat generated during the FSW process. The increase of rotational speed and decrease of transversal speed result in high amount of heat and homogeneous distribution of SiC nano-particles. The former leads to grain growth and decrease of strength and hardness, while the latter causes grain refinement and increases of strength and hardness. Accordingly, the heat input has opposite effects on matrix grain growth and homogeneous distribution of particles. Therefore, optimum values of rotational and transversal speeds were found (800¿r/min and 75¿mm/min) to produce the best microstructure and mechanical properties