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Publicações

2015

Direct or indirect channel structures. Evaluating the impact of channel governance structure on export performance

Autores
Rambocas, M; Meneses, R; Monteiro, C; Brito, PQ;

Publicação
INTERNATIONAL BUSINESS REVIEW

Abstract
The purpose of the study is to examine the impact of channel governance structure on export performance ex post. The study surveyed 105 foreign buyers of crane services from five countries and used MANOVA to test the effects of channel governance structure on export short term and long term performance outcomes. The study found that short term profitability was higher for indirect distribution channel arrangements while longer term outcomes of buyer economic satisfaction and loyalty were higher for direct. The results suggest that exporters are more likely to achieve immediate financial objectives with the support from indirect channels; however, long term objectives are more effectively achieved through direct channels.

2015

Bi-Level Approach for Modeling Multi-Energy Players' Behavior in a Multi-Energy System

Autores
Damavandi, MY; Bahramara, S; Moghaddam, MP; Haghifam, MR; Shafie khah, M; Catalao, JPS;

Publicação
2015 IEEE EINDHOVEN POWERTECH

Abstract
In this paper a bi-level approach is presented to model the behavior of multi-energy players (MEP) who are coupled based on signal price in a multi-energy system (MES). The MEPs are defined as energy players who can trade more than one energy carrier and have energy facilities (e.g. energy storages and converters) to convert and store various energy carriers. In this approach, MEPs trade various energy carriers in the upper level problem and the coupled energy price will be deduced. In the lower level problem MEPs schedule their energy balance based on the upper level signal price. By implementing dual theorem, the bi-level problem is transformed into a single level optimization problem that can be solved with CPLEX optimizer. The proposed model has been applied in an MES with four MEPs and the numerical results demonstrate the proficiency of the modeling framework.

2015

An Approach for Automated Scenario-based Testing of Distributed and Heterogeneous Systems

Autores
Lima, B; Faria, JP;

Publicação
ICSOFT-EA

Abstract
The growing dependence of our society on increasingly complex software systems, makes software testing ever more important and challenging. In many domains, such as healthcare and transportation, several independent systems, forming a heterogeneous and distributed system of systems, are involved in the provisioning of endto- end services to users. However, existing testing techniques, namely in the model-based testing field, provide little tool support for properly testing such systems. Hence, in this paper, we propose an approach and a toolset architecture for automating the testing of end-to-end services in distributed and heterogeneous systems. The tester interacts with a visual modeling frontend to describe key behavioral scenarios, invoke test generation and execution, and visualize test results and coverage information back in the model. The visual modeling notation is converted to a formal notation amenable for runtime interpretation in the backend. A distributed test monitoring and control infrastructure is responsible for interacting with the components of the system under test, as test driver, monitor and stub. At the core of the toolset, a test execution engine coordinates test execution and checks the conformance of the observed execution trace with the expectations derived from the visual model. A real world example from the Ambient Assisted Living domain is presented to illustrate the approach.

2015

Magnetic field measurement using a fiber laser sensor in ring arrangement

Autores
Nascimento, IM; Baptista, JM; Jorge, PAS; Cruz, JL; Andres, MV;

Publicação
OPTICAL SENSORS 2015

Abstract
In this work an optical fiber laser with loop configuration was developed for magnetic field measurement. The transducer element is an FBG written in a HiBi fiber whose wavelength is modified using a magnetostrictive material that applies deformation in the presence of the magnetic field. The laser has a bandwidth of 450 MHz and operates in single polarization. A shift of 258.5 pm was observed in the laser operating wavelength for a magnetic field of 17.85 mT. Moreover, a maximum sensitivity of 14.72 pm/mT in the linear regime operation was achieved when increasing the magnetic field. The system provides a narrow emission line that is dependent on the magnetic field magnitude enabling high resolution interferometric measurement schemes. The laser response to AC magnetic fields was also characterized using a passive interferometer with higher sensitivity in the range of 8.32 to 17.93 mT(RMS).

2015

Power-to-Gas potential assessment of Portugal under special consideration of LCOE

Autores
Heymann, F; Bessa, R;

Publicação
2015 IEEE Eindhoven PowerTech, PowerTech 2015

Abstract
Power-to-Gas can contribute with valuable balancing power and seasonal storage capacity to future power systems. In Portugal, forecasts for 2020 show significant excess of renewable energy generation that can be transformed by power-to-gas technology and fed into the natural gas infrastructure. This work suggests an innovative approach to assess future power-togas integration potentials at the national level, focusing on wind power. Following a geographical distance analysis, a first economical estimation of future energy transformation costs is made with the help of Levelized Costs of Energy (LCOE). © 2015 IEEE.

2015

Toward Educational Virtual Worlds: Should Identity Federation Be a Concern?

Autores
Cruz, G; Costa, A; Martins, P; Gonçalves, R; Barroso, J;

Publicação
EDUCATIONAL TECHNOLOGY & SOCIETY

Abstract
3D Virtual Worlds are being used for education and training purposes in a cross-disciplinary way. However, its widespread adoption, particularly in formal learning contexts, is far from being a reality due a broad range of technological challenges. In this reflection paper, our main goal is to argue why and how identity federation should be discussed and adopted as a solution to several barriers that educators and institutions face when using Virtual Worlds. By presenting a clear set of scenarios within different dimensions of the educational process, as classroom management, content reuse, learning analytics, accessibility, and research, we consider identity, traceability, privacy, accountability, and interoperability as main concerns in order to support our argument. Finally, we conclude the paper by presenting paths to a proposal for a workable solution, through the analysis and reflection of different and current efforts that has been made by other teams, towards future technological developments.

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