A graph-based framework for multiparadigmatic visual access todatabases

Describes an approach for multiparadigmatic visual access integration of different interaction paradigms. The user is provided with an adaptive interface augmented by a user model, supporting different visual representations of both data and queries. The visual representations are characterized on the basis of the chosen visual formalisms, namely forms, diagrams and icons. To access different databases, a unified data model called the “graph model” is used as a common underlying formalism to which databases, expressed in the most popular data models, can be mapped. Graph model databases are queried through the adaptive interface. The semantics of the query operations is formally defined in terms of graphical primitives. Such a formal approach permits us to define the concept of an “atomic query”, which is the minimal portion of a query that can be transferred from one interaction paradigm to another and processed by the system. Since certain interaction modalities and visual representations are more suitable for certain user classes, the system can suggest to the user the most appropriate interaction modality as well as the visual representation, according to the user model. Some results on user model construction are presented     

Guidelines for hypermedia usability inspection

Our research addresses evaluating the usability of hypermedia systems oth offline (CD-ROMs) and online (Web) - and tries to capture the features that most characterize the specific nature of these systems. In this article, we describe an inspection technique that lets evaluators concentrate on the usability of specific aspects of hypermedia applications, such as information and navigation structuring, media integration and synchronization, and so on, without neglecting the surface aspects. Our technique uses operational guidelines, called abstract tasks (ATs), which systematically drive the inspection activities, allowing even less experienced evaluators to come up with valuable results. As they currently exist, we see ATs as evaluation patterns, which make it possible to maximize the reuse of an evaluator's expertise. That is, reuse takes advantage of previous work, thus reducing the effort to create a new one. ATs support the reuse of an evaluator's know-how. Their goal is to capture usability inspection expertise and to express it in a precise and understandable form, so that others can easily reproduce, communicate and exploit it. Our current work is devoted to extending the AT library to cover specific usability issues related to e-commerce Web sites     

A Birkhoff interpolation problem and application

A Birkhoff interpolation problem is studied. The explicit solution and estimation of remainder is given. The cases of equidistant and Chebyshev nodes are considered. This problem is of interest in collocation methods of boundary value problem (Costabile and Napoli in Far East J. Appl. Math. 25(3):289–305, 2006; Costabile and Longo in Applied and Industrial Mathematics in Italy III, 2009, in press). In addition an application to quadrature is given.     

Analysis of One-Dimensional Modelling for Flood Routing in Compound Channels

In this paper a number of hydraulic aspects concerning the flood routing in compound channels are discussed. In particular, attention is firstly focused on the management of boundary conditions for compound channel flow when 1D modelling is used. In this context, the characteristics theory was used to obtain the complete expression of the eigenvalues of the system and the consequences of the simplification associated to the commonly-used approximation were highlighted. The analysis has shown that the number of physical conditions to be imposed at the boundaries is influenced not only by the Boussinesq coefficient but also by its derivative over the water level. The second part of the paper is devoted to the analysis of unsteady flow simulations. Attention was focused on the role played by the lateral momentum transfer, between main channel and floodplains, within the 1D flood propagation model. In particular, the simulations showed that significant differences may occur between the traditional approach and the methods able to take into account the momentum transfer mechanisms.     

Un metodo del terzo ordine per l'integrazione numerica dell'equazione differenziale ordinaria

For the numerical integration of the ordinary differential equation $$\frac{{dy}}{{dx}} = F(x,y) y(x_0 ) = y_0 \begin{array}{*{20}c} x \\ {x_0 } \\ \end{array} \varepsilon [a,b]$$ a third method utilizing only two points for every step, is determined different from the analogous Runge-Kutta method employing three points; it is useless take the first step as the «pseudo Runge-Kutta method». The truncation error is given, the convergence is proved and finally a numerical exercise is given.     

Adoption and Use of Software in Land Use Planning Practice: A Multiple-Country Study

Planning Support Systems (PSS) are computer-based tools that assist professionals in land use planning activities. Although several researchers acknowledge the importance of such tools in planning practice, PSS use is limited due to their poor fit to users’ needs and expectations as well as to their low usability. This article presents a study carried out in three different countries, namely, Australia, Italy, and Switzerland, aiming at investigating in-depth the current situation regarding the adoption of PSS and identifying factors preventing their wider use, devoting particular attention to the quality of such systems from the point of view of their users. The study also aimed at analyzing planners’ expectations in order to identify relevant features that PSS should provide. The main part of the study consisted of 35 interviews with planning experts. A follow-up focus group with six further participants was also performed. The results confirmed some findings of previous studies but also revealed new insights. This article provides suggestions on how to address the emerging issues, as well as pathways for creating software that can be adopted and used with satisfaction in the planning practice.     

End users as co-designers of their own tools and products

In our Age of exponential technological advance, recent developments are determining an evolution of end users from passive information consumers into information producers. Users are increasingly willing and, indeed, determined to shape the software they use to tailor it to their own needs. Based on a brief review of research activities we performed in the last decade, this paper analyzes some challenges that software designers face to comply with the new roles of end users in the software life cycle, and discusses how to provide end users with software environments that empower them to become co-designers of their own tools and products. The examples reported in the paper show why and how end users are involved in design activities in various application domains.     

A class of collocation methods for numerical integration of initial value problems

For the numerical solution of initial value problems a general procedure to determine global integration methods is derived and studied. They are collocation methods which can be easily implemented and provide a high order accuracy. They further provide globally continuous differentiable solutions. Computation of the integrals which appear in the coefficients are generated by a recurrence formula and no integrals are involved in the calculation. Numerical experiments provide favorable comparisons with other existing methods.