Congestion Games with Complementarities

We study a model of selfish resource allocation that seeks to incorporate dependencies among resources as they exist in modern networked environments. Our model is inspired by utility functions with constant elasticity of substitution (CES) which is a well-studied model in economics. We consider congestion games with different aggregation functions. In particular, we study $L_p$ norms and analyze the existence and complexity of (approximate) pure Nash equilibria. Additionally, we give an almost tight characterization based on monotonicity properties to describe the set of aggregation functions that guarantee the existence of pure Nash equilibria.Comment: The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-57586-5_1

Coordination and management of information for construction design projects - a framework for Portugal

In the construction industry in Portugal, the coordination and management of information for construction design projects has been neglected. The use of classification systems and protocols for the communication of information amongst the different stakeholders is poor and inefficient. This research aims to explore the viability of developing a systematic approach to the coordination of information amongst the multiple project stakeholders in the Portuguese Construction Industry. Bearing this in mind, the core research question of this doctoral thesis is: What sort of framework and guidelines are needed for the successful implementation of a classification information system for construction project design data in Portugal, which is accessible to all stakeholders involved? A mixed methods approach was developed for this purpose, with emphasis given to qualitative research techniques. Methods used comprised: literature review, quantitative survey, semi-structured interviews and focus group discussions. Whereas quantitative research methods contributed to a more rigorous interpretation process, qualitative research methods offered a solid description of the former. This methodology was used in order to establish and design a conceptual classification framework model for information coordination and management throughout the design project and construction in Portugal. First, constraints and enablers to framework development and implementation were identified at all levels: political, cultural and behaviour, legal, technical and educational, economic and financial, and organizational issues. Three overarching issues were also identified: corruption, lack of accountability and non-compliance timelines/deadlines. Then, a conceptual framework was developed, detailing 1) content, 2) characteristics of an environment conductive to a successful development, implementation and use of the framework, and 3) guidelines to its dissemination

Local probing of propagating acoustic waves in a gigahertz echo chamber

In the same way that micro-mechanical resonators resemble guitar strings and drums, surface acoustic waves resemble the sound these instruments produce, but moving over a solid surface rather than through air. In contrast with oscillations in suspended resonators, such propagating mechanical waves have not before been studied near the quantum mechanical limits. Here, we demonstrate local probing of surface acoustic waves with a displacement sensitivity of 30 amRMS Hz^(−1/2) and detection sensitivity on the single-phonon level after averaging, at a frequency of 932 MHz. Our probe is a piezoelectrically coupled single-electron transistor, which is sufficiently fast, non-destructive and localized to enable us to track pulses echoing back and forth in a long acoustic cavity, self-interfering and ringing the cavity up and down. We project that strong coupling to quantum circuits will enable new experiments, and hybrids using the unique features of surface acoustic waves. Prospects include quantum investigations of phonon–phonon interactions, and acoustic coupling to superconducting qubits for which we present favourable estimates