Energy Saving in QoS Fog-supported Data Centers

One of the most important challenges that cloud providers face in the explosive growth of data is to reduce the energy consumption of their designed, modern data centers. The majority of current research focuses on energy-efficient resources management in the infrastructure as a service (IaaS) model through "resources virtualization" - virtual machines and physical machines consolidation. However, actual virtualized data centers are not supporting communication–computing intensive real-time applications, big data stream computing (info-mobility applications, real-time video co-decoding). Indeed, imposing hard-limits on the overall per-job computing-plus-communication delays forces the overall networked computing infrastructure to quickly adopt its resource utilization to the (possibly, unpredictable and abrupt) time fluctuations of the offered workload. Recently, Fog Computing centers are as promising commodities in Internet virtual computing platform that raising the energy consumption and making the critical issues on such platform. Therefore, it is expected to present some green solutions (i.e., support energy provisioning) that cover fog-supported delay-sensitive web applications. Moreover, the usage of traffic engineering-based methods dynamically keep up the number of active servers to match the current workload. Therefore, it is desirable to develop a flexible, reliable technological paradigm and resource allocation algorithm to pay attention the consumed energy. Furthermore, these algorithms could automatically adapt themselves to time-varying workloads, joint reconfiguration, and orchestration of the virtualized computing-plus-communication resources available at the computing nodes. Besides, these methods facilitate things devices to operate under real-time constraints on the allowed computing-plus-communication delay and service latency. The purpose of this thesis is: i) to propose a novel technological paradigm, the Fog of Everything (FoE) paradigm, where we detail the main building blocks and services of the corresponding technological platform and protocol stack; ii) propose a dynamic and adaptive energy-aware algorithm that models and manages virtualized networked data centers Fog Nodes (FNs), to minimize the resulting networking-plus-computing average energy consumption; and, iii) propose a novel Software-as-a-Service (SaaS) Fog Computing platform to integrate the user applications over the FoE. The emerging utilization of SaaS Fog Computing centers as an Internet virtual computing commodity is to support delay-sensitive applications. The main blocks of the virtualized Fog node, operating at the Middleware layer of the underlying protocol stack and comprises of: i) admission control of the offered input traffic; ii) balanced control and dispatching of the admitted workload; iii) dynamic reconfiguration and consolidation of the Dynamic Voltage and Frequency Scaling (DVFS)-enabled Virtual Machines (VMs) instantiated onto the parallel computing platform; and, iv) rate control of the traffic injected into the TCP/IP connection. The salient features of this algorithm are that: i) it is adaptive and admits distributed scalable implementation; ii) it has the capacity to provide hard QoS guarantees, in terms of minimum/maximum instantaneous rate of the traffic delivered to the client, instantaneous goodput and total processing delay; and, iii) it explicitly accounts for the dynamic interaction between computing and networking resources in order to maximize the resulting energy efficiency. Actual performance of the proposed scheduler in the presence of: i) client mobility; ii) wireless fading; iii) reconfiguration and two-thresholds consolidation costs of the underlying networked computing platform; and, iv) abrupt changes of the transport quality of the available TCP/IP mobile connection, is numerically tested and compared to the corresponding ones of some state-of-the-art static schedulers, under both synthetically generated and measured real-world workload traces

Propiedades Adhesivas Húmedas de la Proteína del Pie de Mejillones Verdes Asiático (Perna viridis) Pvfp-5: Una Base Adhesiva Subacuática

Los mejillones verdes asiáticos (Perna viridis) son bivalvos que se adhieren firmemente a las rocas en las costas intermareales golpeadas por las olas a través de una secreción proteica. Los mejillones de P. viridis siguen una secreción de proteínas adhesivas regulada en el tiempo, donde la proteína del pie-5 de P. viridis (Pvfp-5) fue identificada como la primera proteína que se secreta durante la formación de la placa adhesiva. El alto contenido de aminoácido catecólico 3,4-dihidroxi-L-fenilalanina (DOPA) (~11% en moles) y cisteína (CYS) (~15% en moles) en Pvfp-5 y su localización cerca de la interfaz placa-sustrato provocó la especulación de que la proteína de vanguardia Pvfp-5 desempeña un papel clave como imprimación adhesiva en la adhesión bajo el agua de los mejillones de P. viridis. El aparato de fuerza de superficie (SFA) se usó para probar las propiedades adhesivas de Pvfp-5 a escala nanométrica, donde se investigó la adhesión húmeda dependiente del pH y la actividad antioxidante de Pvfp-5 purificado y extraído. El estudio reveló que Pvfp-5 con su alto contenido de DOPA y CYS mantiene la adhesión incluso a un pH más alto al superar la oxidación espontánea de DOPA a quinona. Los resultados de SFA son consistentes con la función aparente de que Pvfp-5 actúa como imprimación adhesiva, superando las fuerzas de hidratación repulsivas al desplazar el agua unida a la superficie y generando una adhesión superficial fuerte y duradera. Nuestros hallazgos revelan conocimientos a escala molecular que deberían ser relevantes e impactar en las ciencias de los materiales al desarrollo de la nueva generación de adhesivos, recubrimientos y pegamentos resistentes a la humedad para aplicaciones biomédicas, terapéuticas y antiincrustantes

Memory and memoryless optimal time-window controllers for secondary users in vehicular networks

In this paper, a primary-secondary resource-management controller on vehicular networks is designed and tested. We formulate the resource-management problem as a constrained stochastic network utility maximization problem and derive the optimal resource management controller, which dynamically allocates the access time-windows to the secondary-users. We provide the optimal steady-state controllers under hard and soft primary-secondary collision constraints, showing as the hard controller does not present any optimality gap in the average utility respect to the soft one, while, on the contrary, it is able to make the outage-probability vanishing. Then, we present as a particular case the subset of memoryless controller, that are unable to exploit the system statistics, derive the throughput-gain of the general controllers with respect to the memoryless ones and discuss conditions of applicability and advantages of each subclass

P-SEP: a prolong stable election routing algorithm for energy-limited heterogeneous fog-supported wireless sensor networks

Energy efficiency is one of the main issues that will drive the design of fog-supported wireless sensor networks (WSNs). Indeed, the behavior of such networks becomes very unstable in node's heterogeneity and/or node's failure. In WSNs, clusters are dynamically built up by neighbor nodes, to save energy and prolong the network lifetime. One of the nodes plays the role of Cluster Head (CH) that is responsible for transferring data among the neighboring sensors. Due to pervasive use of WSNs, finding an energy-efficient policy to opt CHs in the WSNs has become increasingly important. Due to this motivations, in this paper, a modified Stable Election Protocol (SEP), named Prolong-SEP (P-SEP) is presented to prolong the stable period of Fog-supported sensor networks by maintaining balanced energy consumption. P-SEP enables uniform nodes distribution, new CH selecting policy, and prolong the time interval of the system, especially before the failure of the first node. P-SEP considers two-level nodes' heterogeneities: advanced and normal nodes. In P-SEP, the advanced and normal nodes have the opportunity to become CHs. The performance of the proposed approach is evaluated by varying the various parameters of the network in comparison with other state-of-the-art cluster-based routing protocols. The simulation results point out that, by varying the initial energy and node heterogeneity parameters, the network lifetime of P-SEP improved by 31, 29, 20 and 40 % in comparison with SEP, Low-Energy Adaptive Clustering Hierarchy with Deterministic Cluster-Head Selection (LEACH-DCHS), Modified SEP (M-SEP) and an efficient modified SEP (EM-SEP), respectively