HARD: Hybrid Adaptive Resource Discovery for Jungle Computing

In recent years, Jungle Computing has emerged as a distributed computing paradigm based on simultaneous combination of various hierarchical and distributed computing environments which are composed by large number of heterogeneous resources. In such a computing environment, the resources and the underlying computation and communication infrastructures are highly-hierarchical and heterogeneous. This creates a lot of difficulty and complexity for finding the proper resources in a precise way in order to run a particular job on the system efficiently. This paper proposes Hybrid Adaptive Resource Discovery (HARD), a novel efficient and highly scalable resource-discovery approach which is built upon a virtual hierarchical overlay based on self-organization and self-adaptation of processing resources in the system, where the computing resources are organized into distributed hierarchies according to a proposed hierarchical multi-layered resource description model. The proposed approach supports distributed query processing within and across hierarchical layers by deploying various distributed resource discovery services and functionalities in the system which are implemented using different adapted algorithms and mechanisms in each level of hierarchy. The proposed approach addresses the requirements for resource discovery in Jungle Computing environments such as high-hierarchy, high-heterogeneity, high-scalability and dynamicity. Simulation results show significant scalability and efficiency of the proposed approach over highly heterogeneous, hierarchical and dynamic computing environments

A Self-organizing and Self-configuration Algorithm for Resource Management in Service-oriented Systems

With the ever increasing deployment of service-oriented distributed systems in large-scale and heterogeneous computing environments, clustering and communication overlay topology design has become more and more important to address several challenging issues and conflicting requirements, such as efficient scheduling and distribution of services among computing resources, reducing communication cost between services, high performance service and resource discovery while considering both inter-service and inter-node properties and also increasing the load distribution and the load balance. In this paper, a four-stage hierarchical clustering algorithm is proposed which automates the process of the optimally composing communicating groups in a dynamic way while preserving the proximity of the nodes. The simulation results show the performance of the algorithm with respect to load balance, scalability and efficiency

A Specification-based Anycast Scheme for Scalable Resource Discovery in Distributed Systems

Anycast is a powerful paradigm for managing and locating resources in large scale distributed computing systems. This paper presents a novel specification-based anycasting scheme for resource discovery in such environments. The effectiveness of our proposal is demonstrated through simulation results, in which we observed a remarkable performance enhancement in different aspects (such as discovery latency, discovery cost, discovery load, etc.) over similar non-anycast based discovery methods

Conformidade da resistência à compressão de betões

O incumprimento das regras específicas e a consequente não conformidade dos betões em relação à normativa vigente pode originar o aparecimento de anomalias e a degradação precoce das construções. Neste contexto procedeu-se à recolha de vários provetes in situ, representativos do betão a aplicar em determinadas obras, com o objectivo de realizar um estudo estatístico com um número suficientemente vasto de resultados exigidos pelas normas, o que permitiu verificar as probabilidades de estas serem respeitadas ou não. A análise dos resultados obtidos evidenciou que em quatro das cinco obras seleccionadas a classe de betão obtida foi superior à exigida, enquanto que numa das obras o betão não verificou os critérios. Nesta obra, a classificação do estaleiro pode ser considerada como média, enquanto nas restantes variou entre bom e muito bom. A classificação foi feita tomando em conta odesvio-padrão dos resultados dos ensaios de resistência à compressão

Experimental and numerical studies of hybrid PCM embedded in plastering mortar for enhanced thermal behaviour of buildings

This paper proposes a methodology for improvement of energy efficiency in buildings through the innovative simultaneous incorporation of three distinct phase change materials (here termed as hybrid PCM) in plastering mortars for façade walls. The thermal performance of a hybrid PCM mortar was experimentally evaluated by comparing the behaviour of a prototype test cell (including hybrid PCM plastering mortar) subjected to realistic daily temperature profiles, with the behaviour of a similar prototype test cell, in which no PCM was added. A numerical simulation model was employed (using ANSYS-FLUENT) to validate the capacity of simulating temperature evolution within the prototype containing hybrid PCM, as well as to understand the contribution of hybrid PCM to energy efficiency. Incorporation of hybrid PCM into plastering mortars was found to have the potential to significantly reduce heating/cooling temperature demands for maintaining the interior temperature within comfort levels when compared to normal mortars (without PCM), or even mortars comprising a single type of PCM.The authors would like to acknowledge the financial support of the Foundation for Science and Technology (FCT) in the frame of: (i) project CENTRO-07-ST24_FEDER-002020; (ii) project PTDC/ECM/ 102154/2008; (iii) C-TAC, ISISE and CeMADE research units

Red mud-based geopolymers with tailored alkali diffusion properties and pH buffering ability

This study develop novel porous red mud (RM) based geopolymers and evaluates their potential to ensure prolonged pH control. Several properties of the novel geopolymers were examined including buffering ability, alkalis leaching behaviour, mineralogical composition, microstructure and physical properties. Two experimental plans were defined to evaluate the influence of porosity and RM content on those properties. The pH values of the eluted water and geopolymers OH ions leaching have been determined over time showing that total OH ions and the leaching rate can be tailored by controlling the geopolymers porous structure and the availability of free alkaline species. The lower pH gradient over 28th d (1.64 pH units) was achieved by combining a 0.025 wt% pore forming agent (aluminium powder) with 45 wt% MK replacement by red mud. A high and prolonged buffer capacity was accomplished, proving that red mud-based geopolymers have potential to be applied as pH buffering material.This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.info:eu-repo/semantics/publishedVersio

Avaliação experimental de compósitos de agregados leves impregnados com PCM, para aplicação em pavimentos rodoviários

Este trabalho visa, em primeiro lugar, a caracterização experimental do comportam ento de argamassas com materiais de mudança de fase (PCM) incorporados através de agregados leves, comparativamente com argamassas de referência sem incorporação de PCM. Verifica-se que a aplicação de argamassas com PCM em camadas de desgaste de pavimentos contribui para a minimização dos potenciais efeitos negativos de gelo e degelo. Os estudos experimentais permitem concluir que o método utilizado de impregnação de PCM em materiais porosos, para posterior incorporação em argamassa ou betão, é um método simples, mas muito eficaz. Os resultados indicam ainda que os materiais compósitos com PCM incorporado, podem melhorar a inércia térmica, bem como, atrasar o tempo de eventual ocorrência de congelamento sob a camada de desgaste de um pavimentoComissão de Coordenação e Desenvolvimento Regional da Região Centro (CCDR-C), através do projeto de investigação CENTRO-07-ST24_FEDER-002020 “Environmentally-Friendly Aeronautical Transport Systems Integrated Program (EFATRAS)”, http://efatrasubi.wordpress.co

Raman excitation spectroscopy of carbon nanotubes: effects of pressure medium and pressure

Raman excitation and emission spectra for the radial breathing mode (RBM) are reported, together with a preliminary analysis. From the position of the peaks on the two-dimensional plot of excitation resonance energy against Raman shift, the chiral indices (m, n) for each peak are identified. Peaks shift from their positions in air when different pressure media are added - water, hexane, sulphuric acid - and when the nanotubes are unbundled in water with surfactant and sonication. The shift is about 2 - 3 cm-1 in RBM frequency, but unexpectedly large in resonance energy, being spread over up to 100meV for a given peak. This contrasts with the effect of pressure. The shift of the peaks of semiconducting nanotubes in water under pressure is orthogonal to the shift from air to water. This permits the separation of the effects of the pressure medium and the pressure, and will enable the true pressure coefficients of the RBM and the other Raman peaks for each (m, n) to be established unambiguously.Comment: 6 pages, 3 Figures, Proceedings of EHPRG 2011 (Paris

A conjugate for the Bargmann representation

In the Bargmann representation of quantum mechanics, physical states are mapped into entire functions of a complex variable z*, whereas the creation and annihilation operators $\hat{a}^\dagger$ and $\hat{a}$ play the role of multiplication and differentiation with respect to z*, respectively. In this paper we propose an alternative representation of quantum states, conjugate to the Bargmann representation, where the roles of $\hat{a}^\dagger$ and $\hat{a}$ are reversed, much like the roles of the position and momentum operators in their respective representations. We derive expressions for the inner product that maintain the usual notion of distance between states in the Hilbert space. Applications to simple systems and to the calculation of semiclassical propagators are presented.Comment: 15 page