From Conventional to State-of-the-Art IoT Access Control Models

open access articleThe advent in Online Social Networks (OSN) and Internet of Things (IoT) has created a new world of collaboration and communication between people and devices. The domain of internet of things uses billions of devices (ranging from tiny sensors to macro scale devices) that continuously produce and exchange huge amounts of data with people and applications. Similarly, more than a billion people are connected through social networking sites to collaborate and share their knowledge. The applications of IoT such as smart health, smart city, social networking, video surveillance and vehicular communication are quickly evolving people’s daily lives. These applications provide accurate, information-rich and personalized services to the users. However, providing personalized information comes at the cost of accessing private information of users such as their location, social relationship details, health information and daily activities. When the information is accessible online, there is always a chance that it can be used maliciously by unauthorized entities. Therefore, an effective access control mechanism must be employed to ensure the security and privacy of entities using OSN and IoT services. Access control refers to a process which can restrict user’s access to data and resources. It enforces access rules to grant authorized users an access to resources and prevent others. This survey examines the increasing literature on access control for traditional models in general, and for OSN and IoT in specific. Challenges and problems related to access control mechanisms are explored to facilitate the adoption of access control solutions in OSN and IoT scenarios. The survey provides a review of the requirements for access control enforcement, discusses several security issues in access control, and elaborates underlying principles and limitations of famous access control models. We evaluate the feasibility of current access control models for OSN and IoT and provide the future development direction of access control for the sam

In Vivo and In Vitro Evaluation of Preventive Activity of Inflammation and Free Radical Scavenging Potential of Plant Extracts from Oldenlandia corymbosa L.

Aims: The present study evaluates the anti-inflammatory and antioxidant activity of the crude dichloromethane (CDCME), ethyl acetate (CEAE), and methanol (CMeE) extracts from the plant Oldenlandia corymbosa L. Background:Oldenlandia species have been popular among the people of the Indian subcontinent to treat several types of internal and external inflammation for a long time. Plant decoctions have been used to battle inflammation in cases of tonsilitis, pneumonia and cholecystitis, among others. Objective: The present work designed to demonstrate the properties of the previously mentioned plant extracts to prevent inflammation both in vivo and in vitro. This work is the first investigation of such extracts from this species and their relationship with anti-inflammatory activity. Method: The anti-inflammatory properties of the Oldenlandia corymbosa L. extracts were evaluated in vitro with the Red Blood Cell (RBC) membrane stabilization method and the protein denaturation method and in vivo with the carrageenan-induced paw oedema method. Furthermore, the free radical scavenging activity of the extracts was carried out with the 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical oxidation, total antioxidant capacity and iron reduction assay. Result: Both in vivo and in vitro studies showed that CDCME had the most predominant effects with the value of 80.5% for RBC membrane stabilization, 60% for inhibition of protein denaturation at the concentration of 1000 µg/mL and 63.28% (after 3 h, * p < 0.05) for inhibition of paw oedema (300 mg/kg bwt) compared to carrageenan-induced mice. The free radical scavenging activity was studied by DPPH, total antioxidant and reducing activity assay. CDCME showed scavenging activity in all the methods and an IC50 value of 473.86 µg/mL for DPPH method. Conclusions: The findings of the study remarked that CDCME of the plant has strong anti-inflammatory and antioxidant effects that validate the traditional use of the plant to get remedy from pain. Other: The plants Oldenlandia corymbosa L. were provided by the Bangladesh Council of Scientific and Industrial Research Laboratory campus, Rajshahi, Bangladesh. Experiments on animals were conducted by ethical permission of Institute of Biological Sciences, University of Rajshahi, Bangladesh (license no: 225/320-IAMEBBC/IBSc)

Preparation, structural characterization, optical, photoluminescence, AC electrical conductivity and broadband dielectric properties of WO3 reinforced PEG/CS blend for futuristic optoelectronic and energy storage devices

Polymer nanocomposites (PNCs) composed of biopolymers and metallic oxides are important classes of materials. In addition to the environmental and economic considerations, these materials became the best candidates for various industrial fields. In the current study, solution cast procedure is used to prepare polymer nanocomposites (PNCs) based on polyethylene glycol (PEG)/chitosan (CS) blend and varying concentrations of tungsten trioxide nanoparticles (WO3 NPs), as a nanofiller. TEM micrograph shows that WO3 NPs have particle sizes of 5–32 nm their shapes are cubic and spherical. The XRD results reveal the semicrystalline of PEG/CS blend through showing three distinct diffraction peaks at 2θ = 7.42°, 19.47° and 23.62° and the degree of crystallinity is decreased after the incorporation of WO3 NPs due to the formation of polymer-nanoparticle interactions as indicated by FTIR spectra. The values of optical energy bandgap (direct and indirect) reduce while the Urbach energy increases with raising the concentration of WO3 NPs in the PEG/CS matrix. The PEG/CS-WO3 films' PL spectra show a photoemission peak at about 387 nm, where this peak loses intensity and becomes broader due to the induced defects and increase of disordering within the nanocomposite films. Additionally, the results of the dielectric investigation show an increase in the dielectric constant, dielectric loss, and AC electrical conductivity, which may be a sign of an increase of charge carriers and the content of amorphous regions that assists the movement of charge carriers. The DC electrical conductivity and conduction mechanism are also reported. Argand plot shows a half semicircle implying the Debye-type relaxation mechanism. The experimental results suggest the use of PEG/CS-WO3 nanocomposites as a possible contender for futuristic energy storage and optoelectronic applications

Nectar secretion dynamics of Ziziphus nummularia: A melliferous species of dry land ecosystems

Nectar is used as raw material for the production of honey and as significant reward in the relationship between bees and plants during pollination. Therefore, it is important to investigate its abundance, dynamics and associated governing factors. Weather conditions are known to influence nectar production, and predicted climate changes may be responsible for future declining in total yield from beekeeping activities. We investigated nectar production as total soluble solids (TSS) of well-known species for honey production, Ziziphus nummularia in a hot-arid environment of Saudi Arabia. Data on nectar samples from bagged flowers of different stages during two blooming seasons, 2013 and 2015 were collected on weekly bases, and the data were correlated with weather conditions (temperature, relative humidity, and wind). A significant difference in TSS amount has been obtained, with 1-day old flowers displaying the higher content. TSS production was varied along the different day intervals, for both years, with a peak of production in the afternoon. In our results, nectar production was not correlated to temperature and wind, but was significantly negatively correlated with relative humidity. According to the current and future weather forecasting conditions, understanding of the relationship between weather conditions and nectar availability turned out to be important predictive information that may be interpreted into an economic projection of incomes from beekeeping activities