IoTSim-Edge: A simulation framework for modeling the behavior of Internet of Things and edge computing environments

With the proliferation of Internet of Things (IoT) and edge computing paradigms, billions of IoT devices are being networked to support data-driven and real-time decision making across numerous application domains, including smart homes, smart transport, and smart buildings. These ubiquitously distributed IoT devices send the raw data to their respective edge device (eg, IoT gateways) or the cloud directly. The wide spectrum of possible application use cases make the design and networking of IoT and edge computing layers a very tedious process due to the: (i) complexity and heterogeneity of end-point networks (eg, Wi-Fi, 4G, and Bluetooth); (ii) heterogeneity of edge and IoT hardware resources and software stack; (iv) mobility of IoT devices; and (iii) the complex interplay between the IoT and edge layers. Unlike cloud computing, where researchers and developers seeking to test capacity planning, resource selection, network configuration, computation placement, and security management strategies had access to public cloud infrastructure (eg, Amazon and Azure), establishing an IoT and edge computing testbed that offers a high degree of verisimilitude is not only complex, costly, and resource-intensive but also time-intensive. Moreover, testing in real IoT and edge computing environments is not feasible due to the high cost and diverse domain knowledge required in order to reason about their diversity, scalability, and usability. To support performance testing and validation of IoT and edge computing configurations and algorithms at scale, simulation frameworks should be developed. Hence, this article proposes a novel simulator IoTSim-Edge, which captures the behavior of heterogeneous IoT and edge computing infrastructure and allows users to test their infrastructure and framework in an easy and configurable manner. IoTSim-Edge extends the capability of CloudSim to incorporate the different features of edge and IoT devices. The effectiveness of IoTSim-Edge is described using three test cases. Results show the varying capability of IoTSim-Edge in terms of application composition, battery-oriented modeling, heterogeneous protocols modeling, and mobility modeling along with the resources provisioning for IoT applications.     

Effect of surface plasmons on spectral switching of polychromatic light with Au-double-slit

It is shown that the generation of surface plasmons on a metal-dielectric interface, i.e., a Au-double-slit and air interface, appreciably affects the intensity of the diffracted light. With a specific example of Au-double-slit and electro-optic devices before the slits, the spectral switching in the diffracted field with the polychromatic light is shown for the first time, to our knowledge. It is found that at the observation point due to the surface plasmon effect the intensity of the diffracted light periodically increases and decreases with the separation of the double-slit.     

Numerical Investigation of the Radial Ore-to-Coke Ratio in the Blast Furnace Throat during Nonuniform Burden Descent

The burden descent in the blast furnace throat affects the radial ore-to-coke ratio, which is directly related to the gas distribution and chemical reactions in the furnace. Herein, the layer structure and the radial ore-to-coke ratio of the burden bed under uniform and nonuniform burden descent are studied numerically by the discrete element method. Two kinds of nonuniform descent are considered, where the descent rate in the furnace center is greater than the descent rate at the wall or vice versa. The descent is realized by deleting particles in virtual boxes of different sizes at the lower end of the simulated domain. The results show that the ore-to-coke ratio decreases where the descent rate is low and increases where the descent rate is high. For a burden profile of the “platform + hopper” type, a faster burden descent in the center has a much stronger influence on the radial ore-to-coke ratio distribution than the case with faster descent at the wall. The size difference between the ore and coke particles and the charging matrix are also found to play a role in the influence of the burden descent on the distribution of the ore-to-coke ratio.     

Evidence for negative differential resistance and switchable diode effect in multiferroic BiFe0.95Sc0.05O3-based resistive random access memory under doping engineering

Journal of Materials Science: Materials in Electronics - This report explores the influence of scandium (Sc) doping on structural, optical, and resistive switching properties of multiferroic...     

Evaluation of flyash-filled and aramid fibre reinforced hybrid polymer matrix composites (PMC) for friction braking applications

Flyash-filled and aramid fibre reinforced phenolic based hybrid polymer matrix composites (PMC) were fabricated followed by their characterization and tribo-evaluation. The friction-fade and friction-recovery behaviour has been rigorously evaluated as a function of in situ braking induced temperature rise in the disc at the braking interface on a Krauss friction testing machine as per the ECE regulations. The fade behaviour has been observed to be highly dependent on the weight fraction of resin i.e. followed a consistent decrease with the decrease in the flyash content, whereas the frictional fluctuations (μ_max − μ_min) has been observed to decrease with the increase in flyash content. A higher recovery response is registered when the flyash content is 80 wt.%. The analysis of friction performance has revealed that the fade and static friction response are the major determinants of overall frictional response. Wear analysis has revealed that material integrity and temperature rise of the disc decide the wear behaviour. Worn surface morphology investigation using SEM has revealed that the dynamics of formation–destruction of contact-patches (friction-layers) and topographical attributes largely influence the friction and wear performance of such composite brake-pads.     

A study of energetics of cooperative interaction using a mutant {lambda}-repressor

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Thermodynamic accounting of ecosystem contribution to economic sectors with application to 1992 U.S. economy

Incorporation of ecological considerations in decision-making is essential for sustainable development, but is hindered by inadequate appreciation of the role of ecosystems, and lack of scientifically rigorous techniques for including their contribution. This paper develops a novel thermodynamic accounting framework for including the contribution of natural capital via thermodynamic input-output analysis. This framework is applied to the 1992 US economy comprising 91 industry sectors, resulting in delineation of the myriad ways in which sectors of the US economy rely on ecosystem products and services. The contribution of ecosystems is represented via the concept of ecological cumulative exergy consumption (ECEC), which is related to emergy analysis but avoids any of its controversial assumptions and claims. The use of thermodynamics permits representation of all kinds of inputs and outputs in consistent units, facilitating the definition of aggregate metrics. Total ECEC requirement indicates the extent to which each economic sector relies directly and indirectly on ecological inputs. The ECEC/money ratio indicates the relative monetary versus ecological throughputs in each sector, and indicates the relationship between the thermodynamic work needed to produce a product or service and the corresponding economic activity. This ratio is found to decrease along economic supply chains, indicating industries that are higher up in the economic food chain price ecosystem contribution more than the basic infrastructure industries such as mining and manufacturing. The ratio of CEC with and without inclusion of ecosystems indicates the extent to which conventional thermoeconomic analysis underestimates the contribution of ecosystems. Such ratios, made available for the first time, provide unique insight into the importance of natural capital, and are especially useful in hybrid thermodynamic life cycle analysis of industrial systems. The approach, data compiled in this work, and the resulting insight provide a more ecologically conscious tool for environmental decision-making, and has potential applications at micro as well as macro scales.     

The occurrence of vulnerable seagrass species Halophila beccarii Ascherson, 1871 from restored mangrove of Koduvally Estuary,south‐west coast of India

The ocean turf grass, Halophila beccarii Ascherson, 1871 was recorded for the first time in the intertidal region of the restored mangrove ecosystem of the Koduvally Estuary on the south‐west coast of India. It was found co‐existing in the shallow muddy area of the mangroves, dominated by mangrove trees of Rhizophora mucronata and Sonneratia alba, and macroalgae, Ulva sp., Enteromorpha sp. and Chaetomorpha sp. The meadow is sparsely scattered with shoots near the mangroves, with a mean density of 720 shoots/m². Details regarding the morphology and hydrographic conditions are described. The occurrence of H. beccarii in the Koduvally estuary is an encouraging sign of improved ecosystem health through mangrove restoration. The development of seagrass meadow in the estuary will improve the sediment stability and water quality. A further comprehensive study on the spatiotemporal variation of this species in the estuary is also recommended for conservation and management of this vulnerable seagrass species.