Foggy clouds and cloudy fogs: a real need for coordinated management of fog-to-cloud computing systems

The recent advances in cloud services technology are fueling a plethora of information technology innovation, including networking, storage, and computing. Today, various flavors have evolved of IoT, cloud computing, and so-called fog computing, a concept referring to capabilities of edge devices and users' clients to compute, store, and exchange data among each other and with the cloud. Although the rapid pace of this evolution was not easily foreseeable, today each piece of it facilitates and enables the deployment of what we commonly refer to as a smart scenario, including smart cities, smart transportation, and smart homes. As most current cloud, fog, and network services run simultaneously in each scenario, we observe that we are at the dawn of what may be the next big step in the cloud computing and networking evolution, whereby services might be executed at the network edge, both in parallel and in a coordinated fashion, as well as supported by the unstoppable technology evolution. As edge devices become richer in functionality and smarter, embedding capacities such as storage or processing, as well as new functionalities, such as decision making, data collection, forwarding, and sharing, a real need is emerging for coordinated management of fog-to-cloud (F2C) computing systems. This article introduces a layered F2C architecture, its benefits and strengths, as well as the arising open and research challenges, making the case for the real need for their coordinated management. Our architecture, the illustrative use case presented, and a comparative performance analysis, albeit conceptual, all clearly show the way forward toward a new IoT scenario with a set of existing and unforeseen services provided on highly distributed and dynamic compute, storage, and networking resources, bringing together heterogeneous and commodity edge devices, emerging fogs, as well as conventional clouds.Peer ReviewedPostprint (author's final draft

Serpentine Soils, Adverse Habitat for Plants Case Study at Peninsular

The unpleasant effect of serpentine soil on plant life has been a topic of many studies for several decades. Infertility and flora selectivity nature of serpentine soils are the features, which made them of interest throughout the world. This research includes a geochemical study on two Malaysian serpentine massifs to introduce their harmful factors concerning vegetation. X-ray fluorescence results on 11 soil samples showed that serpentine soils comprise large values of iron and magnesium (up to 55 wt and 65 wt% respectively) and high amounts of some heavy metals like chromium (1248-18990 μg g-1), nickel (189-1692 μg g-1) and cobalt (95-478 μg g-1). However, soil extraction by ammonium acetate solution revealed that only magnesium is plant available. Besides, serpentine soils are poor in some major plant nutrients such as nitrogen, potassium and phosphorus. This substantial paucity is the main cause of bareness in these lands. Soils in the studied areas are moderately acidic and have the adequate cation holding capacity. Their Ca/Mg quotient is very low (less than 1). The latter with the low availability of the calcium (0.34 m-equiv 100 g-1 in average) is another challenging parameter in serpentine soils, which exerts negative influence on plant growing

Modular Multilevel Converter with Sensorless Diode-Clamped Balancing through Level-Adjusted Phase-Shifted Modulation

Cascaded H-bridge and modular multilevel converters (MMC) are on the rise with emerging applications in renewable energy generation, energy storage, and electric motor drives. However, their well-known advantages come at the price of complicated balancing, high-bandwidth isolated monitoring, and numerous sensors that can prevent MMCs from expanding into highly cost driven markets. Therefore, an obvious trend in research is developing control and topologies that depend less on measurements and benefit from simpler control. Diode-clamped topologies are considered among the more applicable solutions. The main problem with a diode-clamped topology is that it can only balance the module voltages of a string in one direction; therefore, it cannot provide a completely balanced operation. This paper proposes an effective balancing technique for the diode-clamped topology. The proposed solution exploits the dc component of the arm current by introducing a symmetrically level-adjusted phase-shifted modulation scheme, and ensures the balancing current flow is always in the correct direction. The main advantages of this method are sensorless operation, no added computation and control effort, and low overall cost. Analysis and detailed simulations provide insight into the operation of the system as well as the new balancing technique and the experimental results confirm the provided discussions

A Study of the Construction of Female Identity: John Fowles’ The French Lieutenant’s Woman

The issue of identity and female consciousness as one of the major concerns of feminists has always been polemical, for there are different attitudes in formulating gender identity and consequently defining what a woman is. As its theoretical framework, this study relies on Judith Butler’s theory of gender and sexuality and studies the construction of identity in the female characters of John Fowles’ The French Lieutenant’s Woman. Judith Butler, a feminist constructivist, stresses the effect of socially constructed gender roles on creating gender identity and proposes her performative theory of gender and sexuality. In her theory Butler argues that gender is not what one is but what one does. In this sense, gender is not a stable identity from which various acts proceed; rather it is an identity constituted through a stylized repetition of normative gender roles and performances. Regarding gender as performative reveals that, what is taken as an internal essence of gender is actually fabricated through the regulatory frame of interacting discourses. It has an imitative structure which can be deconstructed. The study, thus, focuses on the effect of prescribed gender roles and norms in the process of identity formation, and examines Ernestina Freeman as a conformist character who constitutes her identity by taking on the ideal gender norms of the era and Sarah woodruff who tries to renegotiate and reenact those roles and constructs a sense of self which transcends constraints of the social and cultural hegemonic frame

A Simplified Model for the Battery Ageing Potential Under Highly Rippled Load for Battery Management and Active Degradation Control

Whereas in typical standardized tests batteries are almost exclusively loaded with constant current or relatively slowly changing cycles, real applications involve rapid load ripple, which do not contribute to the net energy. The trend to reduced filter capacitors and even dynamically reconfigurable batteries further increases the ripple. The influence of rippled load on lithium batteries is therefore receiving increased attention. According to recent studies, accelerated ageing strongly depends on the frequency of the ripple. We use electrochemical models to derive a highly simplified regression model that catches the asymptotic behavior and allows parameter identification and calibration to specific cells. The model allows quantitative monitoring of the additional ageing due to ripple current in battery management systems. Furthermore it enables active control of the ageing potential by influencing the frequency content in modern battery systems, such as reconfigurable batteries.Comment: 7 page