On the Impact of Advance Reservations for Energy-Aware Provisioning of Bare-Metal Cloud Resources

International audienceThis work investigates factors that can impact the elasticity of bare-metal resources. We analyse data from a real bare-metal deployment system to build a deployment time model, which is used to evaluate how provisioning time impacts the reservation of bare-metal resources. Climate/Blazar, a reservation framework designed for OpenStack, is discussed. Simulation results show that reservations can help reduce the time to deliver a provisioned cluster to its customer while achieving energy savings similar to those of strategies that switch-off idle resources

Optimising resource costs of cloud computing for education

International audienceThere is a growing interest around the utilisation of cloud computing in education. As organisations involved in the area typically face severe budget restrictions, there is a need for cost optimisation mechanisms that explore unique features of digital learning environments. In this work, we introduce a method based on Maximum Likelihood Estimation that considers heterogeneity of IT infrastructure in order to devise resource allocation plans that maximise platform utilisation for educational environments. We performed experiments using modelled datasets from real digital teaching solutions and obtained cost reductions of up to 30%, compared with conservative resource allocation strategies

Building Effective Global Virtual Teams: An evaluation of the influence of cultural diversity, communication, rust, and leadership on the development of geographically and virtually dispersed teams.

The overall purpose of this research is to evaluate the influence of cultural diversity, communication, trust, and leadership on the development of geographically and virtually dispersed teams. Initially, it started by identifying and studying the literature about Global Virtual Teams (GVTs). Thus, some gaps among the studies were identified, and visual representation was developed using the conceptual framework. Moreover, the author interviewed eight participants – e-leaders and software engineers from two multinational companies - to collect primary data. Thus, identifying typical pattern across interviews helped to answer the research questions. Lastly, by using Interpretivism philosophy, the author has immersed in the reality of each participant to understand the context of their background to be able to get relevant insights. Thus, applying grounded theory methodology on collected data, helped to identify codes and themes to answer the research questions. This research has uncovered a strong relationship between communication and trust, which can go both ways. Thus, trust can intensify collaboration and team performance, but communication can also influence trust development mainly when people collaborate over the camera and in regular meetings. Additionally, it has shown that Emergent Leaders are able to decrease the sense of team virtually across team members by working closely to the formal leader, thus, decentralising the decision-making process and scaling out the communication management. Furthermore, it has shown that initial trust can be fostered by introducing virtual team members to each other or by visiting other virtual teams in their countries early-on. However, delivering results and gaining credibility would help to consolidate this trust. Lastly, having an interpersonal relationship would make it more resilient and durable. Although working with GVTs can be challenging, there are some key aspects which can be taught to all team members early-on, thereby mitigating common issues. However, all members need to be willing to develop these new soft skills such as virtual sub-teaming leadership, rapport building, trust development, expectation management, and communication management, thus benefiting the team bonding and well-being of these ones directly and indirectly involved

Impact of User Patience on Auto-Scaling Resource Capacity for Cloud Services

International audienceAn important feature of most cloud computing solutions is auto-scaling, an operation that enables dynamic changes on resource capacity. Auto-scaling algorithms generally take into account aspects such as system load and response time to determine when and by how much a resource pool capacity should be extended or shrunk. In this article, we propose a scheduling algorithm and auto-scaling triggering strategies that explore user patience, a metric that estimates the perception end-users have from the Quality of Service (QoS) delivered by a service provider based on the ratio between expected and actual response times for each request. The proposed strategies help reduce costs with resource allocation while maintaining perceived QoS at adequate levels. Results show reductions on resource-hour consumption by up to approximately 9% compared to traditional approaches

Comida, Agência e Imitação: Uma Etnografia das Festividades entre Imigrantes Brasileiros na Grande Boston

Resumo: A alimentação pode ser entendida como uma importante via de leitura de processos socioculturais. Com esta perspectiva, realizei uma etnografia com imigrantes brasileiros na Grande Boston, buscando compreender as mudanças e continuidades em suas práticas alimentares após a migração. Neste artigo, concentro-me nos relatos etnográficos dos momentos de festividade, que, embora não sejam cotidianos, são recorrentes e marcam as experiências migratórias dos sujeitos da pesquisa. Busco compreender as práticas alimentares destes eventos por meio dos conceitos de agência (Gell, 1998) e mímesis (Taussig, 1993), assumindo, deste modo, o protagonismo da comida nestes momentos. A comida, assim, constitui-se um elemento ativo das festas, que evoca sentimentos e memórias por meio de sua sensorialidade, e contribui para tornar presente e entrar em contato com o outro. Além disso, são utilizados outros aportes teóricos para compreender as variadas formas como a comensalidade está estritamente relacionada aos vínculos sociais entre os sujeitos. Palavras-chaves: Comida. Imigrantes brasileiros. Agência. Mímesis. Festas.  Abstract:Food can be understood as an important way of reading sociocultural processes. With this perspective, I conducted an ethnography with Brazilian immigrants in Greater Boston, seeking to understand the changes and continuities in their eating practices after migration. In this article, I focus on the ethnographic accounts of the moments of festivity, which, although not daily, are recurrent and mark the migratory experiences of the research subjects. I seek to understand the eating practices of these events through the concepts of agency (Gell, 1998) and mimesis (Taussig, 1993), thus assuming the role of food in these moments. Food, thus, is an active element of the holidays, which evokes feelings and memories through its sensoriality, and contributes to make present and be in contact with the other. In addition, other theoretical contributions are used to understand the varied ways in which commensality is strictly related to social bonds between the subjects. Keywords: Food. Brazilian immigrants. Agency. Mimesis. Parties

Anti-atherogenic properties associated with the antioxidant activity from the hydrophilic extracts of Halimeda incrassata (Chlorophyta, Bryopsidales)

Seaweeds are a source of natural antioxidants having potential application in oxidative stress and associated diseases. In this work, anti-atherogenic properties associated with the antioxidant activity from the hydrophilic extracts of Halimeda incrassata were studied. The phenolic content assessed inthe aqueous extract and fraction phenolic acids (FPA) was 0.13 ± 0.05 and 0.47 ± 0.09 mg of gallic acid equivalents (GAE)/g dry seaweed, respectively. In DPPH?, radical scavenging assay fractions exhibited a dependent concentration. The seaweeds extract inhibited the desoxirribose oxidation in the presenceor absence of EDTA (IC50 = 1.91± 0.09 mg/mL) (IC50 = 2.95 ± 0.01 mg/mL). In vivo antioxidant properties of FPA-H.incrassata were investigated in rats with a CCl4-induced liver injury. Pre-treatment with H.incrassata led to approximately 50% reductions in liver TBARS levels. The treatment with H. incrassataFPA also increased the activity of the CAT enzyme, which in turn resulted in an enhanced antioxidantdefense. The expression of Catalase by PCR-RT technique demonstrated a higher gene expression when compared with that which was observed in the CCl 4-treated group. Antiatherogenic properties were studied in the inhibition of lipoprotein oxidation mediated by Cu2+ or HRP/H2O2, free radicalscavenging, and metal ion chelation, and it was dose dependent with a higher concentration needed for the aqueous extract than for the FPA fraction. Antioxidant activity was also improved in macrophages as evaluated in the cell supernatant (by TBARS formation); and by luminol enhanced chemiluminescence after cell activation with zymosan; and a degree of cell lipoperoxidation wasdecreased by the Halimeda incrassata extract. The results of this work add to the antioxidant potential of the seaweed for its application in oxidative stress associated conditions.Fil: Vidal-Novoa, Alexis. Universidad de la Habana. Facultad de Biología; CubaFil: Costa-Mugica, Ariadna. Universidad de la Habana. Facultad de Biología; CubaFil: Zulueta Díaz, Yenisleidy de Las Mercedes. Universidad de la Habana. Facultad de Biología; Cuba. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Diaz-Gutierrez, Daylín. Universidad de la Habana. Facultad de Biología; CubaFil: de Oliveira e Silva, Ana, Mara. Universidade de Sao Paulo; BrasilFil: Vazquez, Ana María. Center For Molecular Inmunology; CubaFil: Claudina, Zaldívar-Munoz. Universidad de la Habana. Facultad de Biología; CubaFil: Dalva, Assuncao Portari de Mancini. Institute Butantan Sao Paulo; BrasilFil: Mancini-Filho, Jorge. Universidade de Sao Paulo; Brasi

An economic and energy-aware analysis of the viability of outsourcing clustercomputing to a cloud

This paper compares the total cost of ownership of a physical cluster with the cost of a virtual cloudbased cluster. For that purpose, cost models for both a physical cluster and a cluster on a cloud have been developed. The model for the physical cluster takes into account previous works and incorporates a more detailed study of the costs related to energy consumption and the usage of energy-saving strategies. The model for the cluster on a cloud considers pricing options offered by Amazon EC2, such as reserving instances on a long-term basis, and also considers using tools for powering nodes on and off on demand, in order to avoid the costs associated to keeping idle nodes running. Using these cost models, a comparison is made of physical clusters with cloud clusters of a similar size and performance. The results show that cloud clusters are an interesting option for start-ups and other organizations with a high degree of uncertainty with respect to the computational requirements, while physical clusters are still more economically viable for organizations with a high usage rate. © 2012 Elsevier B.V. All rights reserved.The authors are grateful for the financial support received from both the Spanish Ministry of Economy and Competitiveness to develop project TIN2010-17804, and the Generalitat Valenciana for project GV/2012/076.Alfonso Laguna, CD.; Caballer Fernández, M.; Alvarruiz Bermejo, F.; Moltó, G. (2013). An economic and energy-aware analysis of the viability of outsourcing clustercomputing to a cloud. Future Generation Computer Systems. 29(3):704-712. https://doi.org/10.1016/j.future.2012.08.014S70471229

Provisioning Spot Market Cloud Resources to Create Cost-effective Virtual Clusters

Infrastructure-as-a-Service providers are offering their unused resources in the form of variable-priced virtual machines (VMs), known as "spot instances", at prices significantly lower than their standard fixed-priced resources. To lease spot instances, users specify a maximum price they are willing to pay per hour and VMs will run only when the current price is lower than the user's bid. This paper proposes a resource allocation policy that addresses the problem of running deadline-constrained compute-intensive jobs on a pool of composed solely of spot instances, while exploiting variations in price and performance to run applications in a fast and economical way. Our policy relies on job runtime estimations to decide what are the best types of VMs to run each job and when jobs should run. Several estimation methods are evaluated and compared, using trace-based simulations, which take real price variation traces obtained from Amazon Web Services as input, as well as an application trace from the Parallel Workload Archive. Results demonstrate the effectiveness of running computational jobs on spot instances, at a fraction (up to 60% lower) of the price that would normally cost on fixed priced resources.Comment: 14 pages, 4 figures, 11th International Conference on Algorithms and Architectures for Parallel Processing (ICA3PP-11); Lecture Notes in Computer Science, Vol. 7016, 201