Security supportive energy-aware scheduling and energy policies for cloud environments

Cloud computing (CC) systems are the most popular computational environments for providing elastic and scalable services on a massive scale. The nature of such systems often results in energy-related problems that have to be solved for sustainability, cost reduction, and environment protection. In this paper we defined and developed a set of performance and energy-aware strategies for resource allocation, task scheduling, and for the hibernation of virtual machines. The idea behind this model is to combine energy and performance-aware scheduling policies in order to hibernate those virtual machines that operate in idle state. The efficiency achieved by applying the proposed models has been tested using a realistic large-scale CC system simulator. Obtained results show that a balance between low energy consumption and short makespan can be achieved. Several security constraints may be considered in this model. Each security constraint is characterized by: (a) Security Demands (SD) of tasks; and (b) Trust Levels (TL) provided by virtual machines. SD and TL are computed during the scheduling process in order to provide proper security services. Experimental results show that the proposed solution reduces up to 45% of the energy consumption of the CC system. Such significant improvement was achieved by the combination of an energy-aware scheduler with energy-efficiency policies focused on the hibernation of VMs.COST Action IC140

GAME-SCORE: Game-based energy-aware cloud scheduler and simulator for computational clouds

Energy-awareness remains one of the main concerns for today's cloud computing (CC) operators. The optimisation of energy consumption in both cloud computational clusters and computing servers is usually related to scheduling problems. The definition of an optimal scheduling policy which does not negatively impact to system performance and task completion time is still challenging. In this work, we present a new simulation tool for cloud computing, GAME-SCORE, which implements a scheduling model based on the Stackelberg game. This game presents two main players: a) the scheduler and b) the energy-efficiency agent. We used the GAME-SCORE simulator to analyse the efficiency of the proposed game-based scheduling model. The obtained results show that the Stackelberg cloud scheduler performs better than static energy-optimisation strategies and can achieve a fair balance between low energy consumption and short makespan in a very short tim

Energy and performance-aware scheduling and shut-down models for efficient cloud-computing data centers.

This Doctoral Dissertation, presented as a set of research contributions, focuses on resource efficiency in data centers. This topic has been faced mainly by the development of several energy-efficiency, resource managing and scheduling policies, as well as the simulation tools required to test them in realistic cloud computing environments. Several models have been implemented in order to minimize energy consumption in Cloud Computing environments. Among them: a) Fifteen probabilistic and deterministic energy-policies which shut-down idle machines; b) Five energy-aware scheduling algorithms, including several genetic algorithm models; c) A Stackelberg game-based strategy which models the concurrency between opposite requirements of Cloud-Computing systems in order to dynamically apply the most optimal scheduling algorithms and energy-efficiency policies depending on the environment; and d) A productive analysis on the resource efficiency of several realistic cloud–computing environments. A novel simulation tool called SCORE, able to simulate several data-center sizes, machine heterogeneity, security levels, workload composition and patterns, scheduling strategies and energy-efficiency strategies, was developed in order to test these strategies in large-scale cloud-computing clusters. As results, more than fifty Key Performance Indicators (KPI) show that more than 20% of energy consumption can be reduced in realistic high-utilization environments when proper policies are employed.Esta Tesis Doctoral, que se presenta como compendio de artículos de investigación, se centra en la eficiencia en la utilización de los recursos en centros de datos de internet. Este problema ha sido abordado esencialmente desarrollando diferentes estrategias de eficiencia energética, gestión y distribución de recursos, así como todas las herramientas de simulación y análisis necesarias para su validación en entornos realistas de Cloud Computing. Numerosas estrategias han sido desarrolladas para minimizar el consumo energético en entornos de Cloud Computing. Entre ellos: 1. Quince políticas de eficiencia energética, tanto probabilísticas como deterministas, que apagan máquinas en estado de espera siempre que sea posible; 2. Cinco algoritmos de distribución de tareas que tienen en cuenta el consumo energético, incluyendo varios modelos de algoritmos genéticos; 3. Una estrategia basada en la teoría de juegos de Stackelberg que modela la competición entre diferentes partes de los centros de datos que tienen objetivos encontrados. Este modelo aplica dinámicamente las estrategias de distribución de tareas y las políticas de eficiencia energética dependiendo de las características del entorno; y 4. Un análisis productivo sobre la eficiencia en la utilización de recursos en numerosos escenarios de Cloud Computing. Una nueva herramienta de simulación llamada SCORE se ha desarrollado para analizar las estrategias antes mencionadas en clústers de Cloud Computing de grandes dimensiones. Los resultados obtenidos muestran que se puede conseguir un ahorro de energía superior al 20% en entornos realistas de alta utilización si se emplean las estrategias de eficiencia energética adecuadas. SCORE es open source y puede simular diferentes centros de datos con, entre otros muchos, los siguientes parámetros: Tamaño del centro de datos; heterogeneidad de los servidores; tipo, composición y patrones de carga de trabajo, estrategias de distribución de tareas y políticas de eficiencia energética, así como tres gestores de recursos centralizados: Monolítico, Two-level y Shared-state. Como resultados, esta herramienta de simulación arroja más de 50 Key Performance Indicators (KPI) de rendimiento general, de distribucin de tareas y de energía.Premio Extraordinario de Doctorado U

SCORE: Simulator for cloud optimization of resources andenergy consumption

Achieving efficiency both in terms of resource utilisation and energy consumption is acomplex challenge, especially in large-scale wide-purpose data centers that serve cloud- computing services. Simulation presents an appropriate solution for the development andtesting of strategies that aim to improve efficiency problems before their applications inproduction environments. Various cloud simulators have been proposed to cover differentaspects of the operation environment of cloud-computing systems. In this paper, we define the SCORE tool, which is dedicated to the simulation of energy-efficient monolithicand parallel-scheduling models and for the execution of heterogeneous, realistic and synthetic workloads. The simulator has been evaluated through empirical tests. The results ofthe experiments confirm that SCORE is a performant and reliable tool for testing energy- efficiency, security, and scheduling strategies in cloud-computing environments.European Cooperation in Science and Technology (COST) COST Action IC140

What qualities do government-owned venture capital investors seek in a new venture? A comparison of investment criteria across pre-seed, seed, and expansion stage startups

Private venture capital (VC) investors usually do not invest in early life-cycle stage startups such as seed and pre-seed companies, since investment size typically doesn’t reach investment thresholds. The entry of governments with fund managers to venture capital markets presents seed and pre-seed companies with the opportunity to receive funding. This paper examines the main investment preferences of Hungarian government-owned venture capital investors regarding pre-seed, seed, and expansion stage startups. Verbal protocol analysis enabled examination of the screening process in real-time in all three life-cycle stages. It is found that governmental VC funds mostly value financial indicators followed by market-related qualities while private VCs value these characteristics in alternate formation. However, in the pre-seed stage, the financial acumen and capabilities of management teams form the main criteria in similarity to angel investors. Governmental VCs also greatly seek innovational value in target firms

A methodology for simulation production systems considering the degree of autonomy

The increasing number of product varieties and declining product life cycles combined with individualised customer behaviour demand flexible and efficient production systems. A proper solution approach can be the use of intelligent technologies, capable of autonomous processing in order to react rapidly to changing requirements. However, production planners need a profound planning approach for the implementation of such technologies in production systems due to their cost intense investments. Therefore, simulation studies are suitable means for the analysis of a proper degree of autonomy in production systems. An appropriate methodology for the simulation of such systems is presented in this paper. The methodology is aligned with common guidelines on simulation studies and focuses on system analysis, formalisation and simulation. It is based on consistent methods – fact sheets and Value Stream Design for system analysis, Unified Modelling Language (UML) diagrams for formalisation and agent-based simulation. A central contribution to current research is the modular modelling of intelligence skills in production resources and parts in a simulation environment. Consequently, the developed methodology provides a basis for the implementation of simulation experiments in order to facilitate the evaluation of the economically efficient use of intelligent objects in production systems

Productive Efficiency of Energy-Aware Data Centers

Information technologies must be made aware of the sustainability of cost reduction. Data centers may reach energy consumption levels comparable to many industrial facilities and small-sized towns. Therefore, innovative and transparent energy policies should be applied to improve energy consumption and deliver the best performance. This paper compares, analyzes and evaluates various energy efficiency policies, which shut down underutilized machines, on an extensive set of data-center environments. Data envelopment analysis (DEA) is then conducted for the detection of the best energy efficiency policy and data-center characterization for each case. This analysis evaluates energy consumption and performance indicators for natural DEA and constant returns to scale (CRS). We identify the best energy policies and scheduling strategies for high and low data-center demands and for medium-sized and large data-centers; moreover, this work enables data-center managers to detect inefficiencies and to implement further corrective actions.Universidad de Sevilla 2018/0000052

A társadalmi fenntarthatóság és jól-lét a demenciával élők informális ápolói körében = Social sustainability and well-being among informal carers of people with dementia

A doktori értekezés a szerző három publikációján alapul. Az egy angol és a két magyar nyelvű publikáció közös elméleti hátterét a demencia, a társadalmi fenntarthatóság, a jól-lét és életminőség, a társadalom elöregedése és az informális ápolás jelentik. Ahogy a cikkek alapját képező kutatásoknak, illetve összegző írás elkészítésének, úgy az értekezésnek is elsődleges célja gyakorlati segítség nyújtása a demenciával élőket gondozó hozzátartozóknak. Az értekezésben ezért szakpolitikai javaslatok kerülnek megfogalmazásra. 1. A demenciával élőket és az őket gondozókat, családtagokat, ismerősöket, azaz minden érintettet láthatóvá kell tenni. A kognitív zavar fennállásának igazolásán túl elengedhetetlen a beteg környezetének felmérése, a környezetében vagy vele élők beazonosítása. Mindazokat láthatóvá kell tenni, akik az elkerülhetetlen gondozási tevékenységben egyszer majd kényszerűen vagy szabad döntésükből következően szerepet vállalnak. 2. Nem elég azonban az informális ápolókról tudni, fontos lenne a gondozó laikusok tulajdonságait is felmérni, az irodalomban ismert stressz- és rizikótényezők alapján egy adott társadalmon belül elkülöníthető informális ápoló típusokat azonosítani kell. A saját kutatás eredményeként beazonosított, „pszichológiai működésként” meghatározott típusbesorolást a hazai gondozók esetén is javasolt elvégezni, a hazai adottságokat is figyelembe vevő típus-meghatározó – azaz rizikó, illetve védő – tényezőket azonosítani, ahogy az történt az új-zélandi adatbázison végzett kutatásban. 3. A megismert hazai szükséglet típusoknak megfelelő támogatási formákat kell kidolgozni és biztosítani. Így például az aktív korú informális ápolók számára a munkajövedelem biztosítása lehet az elsődleges cél, míg az idősebb gondozó korosztályhoz tartozók számára akár fizikai segítség nyújtása. A társadalmi fenntarthatóság szempontjából kritikus kérdés a szolgáltatásokhoz való hozzáférés biztosítása, mivel az informális ápolási tevékenység a társadalmi egyenlőtlenséget potenciálisan fokozza. 4. Ahogy a kutatások igazolták, a közösségnek kiemelkedő szerepe van a demenciával élők és a róluk gondoskodók életminőségének fenntartásában. Korosztálytól függetlenül elő kell segíteni a társadalmi kapcsolatok fenntartását, illetve a támogató 2 közösséghez való kapcsolódást, mivel mindezek igazoltan védőfaktorok a gondozók és gondozottak jól-létének vonatkozásában. 5. Minden felsorolt javaslat sok országban egy szakterületeken átívelő cselekvési tervben kerül megfogalmazásra az érintettek széles körével történt egyeztetést követően. Ilyen demencia stratégiára Magyarországnak is szüksége van. Az előttünk lévő példák összegzése, az azokból megismerhető hatékony cselekvések, jó példák megkönnyítik a hazai döntéshozók helyzetét, egyúttal megerősítve, hogy minden országnak saját, az adottságait, képességeit, igényeit figyelembe vevő terv kell, utóbbihoz pedig a kutatások ösztönzése, támogatása

ANALYTICAL MODELING AND SIMULATION OF RELIABILITY OF A CLOSED HOMOGENEOUS SYSTEM WITH AN ARBITRARY NUMBER OF DATA SOURCES AND LIMITED RESOURCES FOR THEIR PROCESSING

Continuous development of computer networks and data transmission systems underlines the growing need for adequate mathematical models and methods for analyzing the performance and reliability metrics of these systems, taking into account the performance of their redundant components. We consider a mathematical model of a repairable data transmission system as a model of a closed homogeneous cold standby system with a single repair facility and with exponentially distributed lifetimes and generally distributed repair times of the system's elements. We study the system-level reliability, defined as the stationary probability of failure-free operation of the considered system. The proposed analytical methodology made it possible to evaluate the reliability of the entire system in case of failures of its elements. Explicit analytical expressions were obtained for the stationary probability of the system's failure-free operation and stationary system state probabilities, which allow analyzing other operational characteristics of the system with respect to the performance of its redundant elements. Explicit analytical expressions for the stationary state probabilities of the considered system cannot always be obtained; therefore, to obtain results in the case of general distribution of elements' repair time, a discrete-event simulation model was constructed to approximate the analytical model of the system. The simulation algorithm was programmatically implemented in R. The comparison of numerical and graphical results obtained using both analytical and simulation approaches showed that they were in close agreement, so the proposed simulation model can be used in cases where the analytical solution cannot be obtained explicitly or as part of a more complex simulation model. We’ve also studied the problem of analyzing the sensitivity of the reliability characteristics of the system at hand to the shape of input distributions. The obtained formulas showed the presence of an explicit dependence of these characteristics on the types of distribution functions of the repair time of the system's elements. However, numerical studies and graphical analysis have shown that this dependence becomes vanishingly small with the “fast” restoration of the system's element