Abstract
A statistical model linking the probability of detecting photons in a photon counting experiment to the average number of input photons is used to analytically derive an error distribution of the estimates of the average number of photons in coherent input pulses. The estimates distribution determines the required number of experimental count runs required for an acceptable measurement error, for any value of the average number of input photons. An expression for the minimum detectable power by photon counting is obtained, fully capturing the effect of the photon counting statistics thereby completing an earlier analysis.

Abstract

Abstract
The current ubiquitous network access and increase in network bandwidth are driving the sales of mobile location-aware user devices and, consequently, the development of context-aware applications, namely location-based services. The goal of this project is to provide consumers of location-based services with a richer end-user experience by means of service composition, personalization, device adaptation and continuity of service. Our approach relies on a multi-agent system composed of proxy agents that act as mediators and providers of personalization meta-services, device adaptation and continuity of service for consumers of pre-existing location-based services. These proxy agents, which have Web services interfaces to ensure a high level of interoperability, perform service composition and take in consideration the preferences of the users, the limitations of the user devices, making the usage of different types of devices seamless for the end-user. To validate and evaluate the performance of this approach, use cases were defined, tests were conducted and results gathered which demonstrated that the initial goals were successfully fulfilled.

Abstract
Model-Driven Engineering (MDE) is a Software Engineering approach based on model transformations at different abstraction levels. It prescribes the development of software by successively transforming models from abstract (specifications) to more concrete ones (code). Alloy is an increasingly popular lightweight formal specification language that supports automatic verification. Unfortunately, its widespread industrial adoption is hampered by the lack of an ecosystem of MDE tools, namely code generators. This paper presents a model transformation between Alloy and UML Class Diagrams annotated with OCL. The proposed transformation enables current UML-based tools to also be applied to Alloy specifications, thus unleashing its potential for MDE. © 2011 Springer-Verlag.

Abstract
We show experimental results of clock recovery from return-to-zero (RZ) format data by using injection locking of a free-running optoelectronic oscillator (OEO) circuit, which consists of a resonant tunneling diode (RTD) oscillator integrated circuit with both a detector and optical source. Error free extraction of a clock signal from the RTD-OEO is shown under both optical and electrical injection. The clock recovery performance at similar to 1.25 Gb/s is analyzed in terms of timing jitter, phase noise and locking bandwidth.

Abstract
Defining functions over large, possibly recursive, data structures usually involves a lot of boilerplate. This code simply traverses non-interesting parts of the data, and rapidly becomes a maintainability problem. Many generic programming libraries have been proposed to address this issue. Most of them allow the user to specify the behavior just for the interesting bits of the structure, and provide traversal combinators to "scrap the boilerplate". The expressive power of these libraries usually comes at the cost of efficiency, since runtime checks are used to detect where to apply the type-specific behavior. In previous work we have developed an effective rewrite system for specialization and optimization of generic programs. In this paper we extend it to also cover recursive data types. The key idea is to specialize traversal combinators using well-known recursion patterns, such as folds or paramorphisms. These are ruled by a rich set of algebraic laws that enable aggressive optimizations. We present a type-safe encoding of this rewrite system in Haskell, based on recent language extensions such as type-indexed type families.