2017
Authors
Garrido, P; Soares, F; Moreira, AP;
Publication
Lecture Notes in Electrical Engineering
Abstract
2017
Authors
Witell, L; Gebauer, H; Jaakkola, E; Hammedi, W; Patricio, L; Perks, H;
Publication
JOURNAL OF BUSINESS RESEARCH
Abstract
Service innovation is often viewed as a process of accessing the necessary resources, (re)combining them, and converting them into new services. The current knowledge on success factors for service innovation, such as formalized new service development (NSD) processes, predominantly comes from studying large firms with a relatively stable resource base. However, this neglect situations in which organizations face severe resource constraints. This paper argues that under such constraints, a formalized new service development process could be counter-productive and a bricolage perspective might better explain service innovation in resource constrained environments. In this conceptual paper, we propose that four critical bricolage capabilities (addressing resource scarcity actively, making do with what is available, improvising when recombining resources, and networking with external partners) influence service innovation outcomes. Empirical illustrations from five organizations substantiate our conceptual development. Our discussion leads to a framework and four testable propositions that can guide further service research.
2017
Authors
Carneiro, I; Carvalho, S; Henrique, R; Oliveira, L; Tuchin, VV;
Publication
JOURNAL OF BIOMEDICAL OPTICS
Abstract
The optical dispersion and water content of human liver were experimentally studied to estimate the optical dispersions of tissue scatterers and dry matter. Using temporal measurements of collimated transmittance [T-c(t)] of liver samples under treatment at different glycerol concentrations, free water and diffusion coefficient (D-gl) of glycerol in liver were found as 60.0% and 8.2 x 10(-7) cm(2)/s, respectively. Bound water was calculated as the difference between the reported total water of 74.5% and found free water. The optical dispersion of liver was calculated from the measurements of refractive index (Rl) of tissue samples made for different wavelengths between 400 and 1000 nm. Using liver and water optical dispersions at 20 degrees C and the free and total water, the dispersions for liver scatterers and dry matter were calculated. The estimated dispersions present a decreasing behavior with wavelength. The dry matter dispersion shows higher Rl values than liver scatterers, as expected. Considering 600 nm, dry matter has an Rl of 1.508, whereas scatterers have an Rl of 1.444. These dispersions are useful to characterize the Rl matching mechanism in optical clearing treatments, provided that [T-c(t)] and thickness measurements are performed during treatment. The knowledge of D-gl is also important for living tissue cryoprotection applications. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
2017
Authors
Ricardo, M; Campos, R; Ruela, J; Morla, R; Teixeira, F; Pessoa, LM; Salgado, HM;
Publication
Wireless Days
Abstract
2017
Authors
Alonso, Ana Luísa Parreira Nunes;
Publication
Abstract
A common pattern for enterprise applications, particularly in small and medium
businesses, is the reliance on an integrated traditional relational database system
that provides persistence and where the relational aspect underlies the core logic
of the application. While several solutions are proposed for scaling out such
applications, database replication is key if the relational aspect is to be preserved.
However, it is worrisome that because proposed solutions for database replication
have been evaluated using simple synthetic benchmarks, their applicability
to enterprise applications is not straightforward: the performance of conservative
solutions hinges on the ability to conveniently partition applications while optimistic
solutions may experience unacceptable abort rates, compromising fairness,
particularly considering long-running transactions.
In this thesis, we address these challenges. First, by performing a detailed
evaluation of the applicability of database replication protocols based on conservative
concurrency control to enterprise applications. Results invalidate the
common assumption that real-world databases can be easily partitioned. Then,
we tackle the issue of unacceptable abort rates in optimistic solutions by proposing
a novel transaction scheduler, AJITTS, which uses an adaptive mechanism
that by reaching and maintaining the optimal level of concurrency in the system,
minimizes aborts and improves throughput.;Um padrão comum no que toca a aplicações empresariais, particularmente em pequenas e médias empresas, é a dependência de um sistema de base dados relacional integrado que garante a persistência dos dados e no qual o aspeto relacional é parte integral da logica da aplicação. Embora várias soluções tenham sido propostas para dotar este tipo de aplicações de escalabilidade horizontal, a replicação de base de dados é a solução se o aspeto relacional deve ser preservado.
No entanto, é preocupante que, dado que as soluções existentes para replicação de base de dados têm sido avaliadas utilizando testes de desempenho sintéticos e simples, a aplicabilidade destes a aplicações empresariais não é directa: o desempenho de soluções conservadoras está intimamente ligado à capacidade de particionar a aplicação convenientemente, enquanto que soluções optimistas podem sofrer de taxas de insucesso inaceitáveis o que compromete a equidade das mesmas, em particular no caso de transações especialmente longas.
Nesta tese, abordamos estes desafios. Primeiro, através de uma avaliação detalhada da aplicabilidade de protocolos de replicação de base de dados baseados em controlo de concorrência conservador a aplicações empresariais. Os resultados obtidos invalidam o pressuposto comum de que bases de dados reais podem ser facilmente particionadas. Assim sendo, abordámos o problema das possíveis taxas de insucesso inaceitáveis em soluções optimistas propondo um novo escalonador de transações, o AJITTS, que utiliza um mecanismo adaptativo que ao atingir e manter o nível ótimo de concorrência no sistema, minimiza a taxa de insucesso e melhora o desempenho do mesmo.
2017
Authors
Cardoso, JM; Coutinho, JGF; Diniz, PC;
Publication
Embedded Computing for High Performance
Abstract
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