Wavelength flattened directional couplers for mirrorsymmetric interferometers

In the context of guided optics, we derive, analytically and geometrically, a rigorous general criterion to design wavelength insensitive interferometers with mirror symmetry, which are needed for wavelength multiplexing/demultiplexing. The criterion is applied to a practical case, resulting in an interferometer that works on a band wider than 70 nm.Comment: 21 pages, 9 figure

A Parametric Hierarchical Planner for Experimenting Abstraction Techniques

This paper presents a parametric system, devised and implemented to perform hierarchical planning by delegating the actual search to an external planner (the "parameter") at any level of abstraction, including the ground one. Aimed at giving a better insight of whether or not the exploitation of abstract spaces can be used for solving complex planning problems, comparisons have been made between instances of the hierarchical planner and their non hierarchical counterparts. To improve the significance of the results, three different planners have been selected and used while performing experiments. To facilitate the setting of experimental environments, a novel semi-automatic technique, used to generate abstraction hierarchies starting from ground-level domain descriptions, is also described

A Critical Look at the Abstraction Based on Macro-Operators

Abstraction can be an effective technique for dealing with the complexity of planning tasks. This paper is aimed at assessing and identifying in which cases abstraction can actually speed-up the overall search. In fact, it is well known that the impact of abstraction on the time spent to search for a solution of a planning problem can be positive or negative, depending on several factors -including the number of objects defined in the domain, the branching factor, and the plan length. Experimental results highlight the role of such aspects on the overall performance of an algorithm that performs the search at the ground-level only, and compares them with the ones obtained by enforcing abstraction

Hybrid choice model for propensity to travel and tour complexity

During the last years cities around the world have invested important quantities of money in measures for reducing congestion and car-trips. Investments which are nothing but potential solutions for the well-known urban sprawl phenomenon, also called the “development trap” that leads to further congestion and a higher proportion of our time spent in slow moving cars. Over the path of this searching for solutions, the complex relationship between urban environment and travel behaviour has been studied in a number of cases. The main question on discussion is, how to encourage multi-stop tours? Thus, the objective of this paper is to verify whether unobserved factors influence tour complexity. For this purpose, we use a data-base from a survey conducted in 2006-2007 in Madrid, a suitable case study for analyzing urban sprawl due to new urban developments and substantial changes in mobility patterns in the last years. A total of 943 individuals were interviewed from 3 selected neighbourhoods (CBD, urban and suburban). We study the effect of unobserved factors on trip frequency. This paper present the estimation of an hybrid model where the latent variable is called propensity to travel and the discrete choice model is composed by 5 alternatives of tour type. The results show that characteristics of the neighbourhoods in Madrid are important to explain trip frequency. The influence of land use variables on trip generation is clear and in particular the presence of commercial retails. Through estimation of elasticities and forecasting we determine to what extent land-use policy measures modify travel demand. Comparing aggregate elasticities with percentage variations, it can be seen that percentage variations could lead to inconsistent results. The result shows that hybrid models better explain travel behavior than traditional discrete choice models

Energy consumption management in Smart Homes: An M-Bus communication system

Energy consumption management in Smart Home environments relies on the implementation of systems of cooperative intelligent objects named Smart Meters. In order for devices to cooperate to smart metering applications' execution, they need to make their information available. In this paper we propose a framework that aims at managing energy consumption of controllable appliances in groups of Smart Homes belonging to the same neighbourhood or condominium. We consider not only electric power distribution, but also alternative energy sources such as solar panels. We define a communication paradigm based on M-Bus for the acquisition of relevant data by managing nodes. We also provide a lightweight algorithm for the distribution of the available alternative power among houses. Performance evaluation of experiments in simulation mode prove that the proposed framework does not jeopardise the lifetime of Smart Meters, particularly in typical situations where managed devices do not continuously turn on and off

PACMAS: A Personalized, Adaptive, and Cooperative MultiAgent System Architecture

In this paper, a generic architecture, designed to support the implementation of applications aimed at managing information among different and heterogeneous sources, is presented. Information is filtered and organized according to personal interests explicitly stated by the user. User pro- files are improved and refined throughout time by suitable adaptation techniques. The overall architecture has been called PACMAS, being a support for implementing Personalized, Adaptive, and Cooperative MultiAgent Systems. PACMAS agents are autonomous and flexible, and can be made personal, adaptive and cooperative, depending on the given application. The peculiarities of the architecture are highlighted by illustrating three relevant case studies focused on giving a support to undergraduate and graduate students, on predicting protein secondary structure, and on classifying newspaper articles, respectively

Relazione tra castrazione e ipotiroidismo nella cagna

Lo scopo del nostro studio è la valutazione dell’eventuale correlazione tra ovariectomia nella cagna e rischio di sviluppo di ipotiroidismo. A tale scopo sono state prese in esame 57 cagne presentatesi alla visita clinica per problematiche indipendenti dalle valutazioni del nostro studio. Di queste, 27 erano castrate e 30 intere. Una volta sottoposte a visita clinica, esclusa l’evidenza sintomatologica di patologie concomitanti che potessero presumibilmente influenzare l’attività tiroidea, si è proceduto a prelievo ematico e dosaggio plasmatico di TSH e fT4. Il nostro studio non ha evidenziato una differenza statisticamente significativa dei tassi plasmatici degli ormoni tiroidei tra cagne intere e castrate. Per questo motivo è nostra opinione che l’ovariectomia non abbia influenza sul rischio di sviluppo di ipotiroidismo nella cagn

A Choice Modelling Approach for Assessment of Use and Quasi-Option Values in Urban Planning for Areas of Environmental Interest

This study adopts a discrete choice modelling methodology to evaluate individuals’ preferences over planning alternatives for an urban site of environmental interest. Since such projects involve some uncertainty and irreversibility, a special attention is devoted to the estimation of the quasi-option values which are associated to project development. Two distinct measures for the quasi-option value are estimated, and both coefficients indicate that the public places a significant value on reduction of the possibility of adverse irreversible effects: a more prudent development strategy is valued about four times more than a procedure that provides a lesser hedge against undesired outcomes. Furthermore, the study involved elicitation of intertemporal preferences over projects with different time spans, and estimation of the implicit discount rates: the values obtained seem high if compared to standard discount rates applied to public projects, but not far from current interest rates on consumption.Urban Planning, Environmental Values, Choice Modelling, Use Values, Quasi-option Values, Discounting