A dataflow platform for applications based on Linked Data

Modern software applications increasingly benefit from accessing the multifarious and heterogeneous Web of Data, thanks to the use of web APIs and Linked Data principles. In previous work, the authors proposed a platform to develop applications consuming Linked Data in a declarative and modular way. This paper describes in detail the functional language the platform gives access to, which is based on SPARQL (the standard query language for Linked Data) and on the dataflow paradigm. The language features interactive and meta-programming capabilities so that complex modules/applications can be developed. By adopting a declarative style, it favours the development of modules that can be reused in various specific execution context

SPARQL Playground: A block programming tool to experiment with SPARQL

SPARQL is a powerful query language for SemanticWeb data sources but one which is quite complex to master. As the block programming paradigm has been succesfully used to teach programming skills, we propose a tool that allows users to build and run SPARQL queries on an endpoint without previous knowledge of the syntax of SPARQL and the model of the data in the endpoint (vocabularies and semantics). This user interface attempts to close the gap between tools for the lay user that do not allow to express complex queries and overtly complex technical tools

Conditions, constraints and contracts: on the use of annotations for policy modeling.

Organisational policies express constraints on generation and processing of resources. However, application domains rely on transformation processes, which are in principle orthogonal to policy specifications and domain rules and policies may evolve in a non-synchronised way. In previous papers, we have proposed annotations as a flexible way to model aspects of some policy, and showed how they could be used to impose constraints on domain configurations, how to derive application conditions on transformations, and how to annotate complex patterns. We extend the approach by: allowing domain model elements to be annotated with collections of elements, which can be collectively applied to individual resources or collections thereof; proposing an original construction to solve the problem of annotations remaining orphan , when annotated resources are consumed; introducing a notion of contract, by which a policy imposes additional pre-conditions and post-conditions on rules for deriving new resources. We discuss a concrete case study of linguistic resources, annotated with information on the licenses under which they can be used. The annotation framework allows forms of reasoning such as identifying conflicts among licenses, enforcing the presence of licenses, or ruling out some modifications of a licence configuration

A doctrinal approach to modal/temporal Heyting logic and non-determinism in processes

The study of algebraic modelling of labelled non-deterministic concurrent processes leads us to consider a category LB , obtained from a complete meet-semilattice B and from B-valued equivalence relations. We prove that, if B has enough properties, then LB presents a two-fold internal logical structure, induced by two doctrines definable on it: one related to its families of subobjects and one to its families of regular subobjects. The first doctrine is Heyting and makes LB a Heyting category, the second one is Boolean. We will see that the difference between these two logical structures, namely the different behaviour of the negation operator, can be interpreted in terms of a distinction between non-deterministic and deterministic behaviours of agents able to perform computations in the context of the same process. Moreover, the sorted first-order logic naturally associated with LB can be extended to a modal/temporal logic, again using the doctrinal setting. Relations are also drawn to other computational model

A human computer interactions framework for biometric user identification

Computer assisted functionalities and services have saturated our world becoming such an integral part of our daily activities that we hardly notice them. In this study we are focusing on enhancements in Human-Computer Interaction (HCI) that can be achieved by natural user recognition embedded in the employed interaction models. Natural identification among humans is mostly based on biometric characteristics representing what-we-are (face, body outlook, voice, etc.) and how-we-behave (gait, gestures, posture, etc.) Following this observation, we investigate different approaches and methods for adapting existing biometric identification methods and technologies to the needs of evolving natural human computer interfaces

Mobiles and wearables: owner biometrics and authentication

We discuss the design and development of HCI models for authentication based on gait and gesture that can be supported by mobile and wearable equipment. The paper proposes to use such biometric behavioral traits for partially transparent and continuous authentication by means of behavioral patterns. © 2016 Copyright held by the owner/author(s)

Human-centric Computing and Information Sciences

Promozione rivista Attività di Revision

International Conference on Graph Transformation

Graphs are among the simplest and most universal models for a variety of systems, not just in computer science, but throughout engineering and the life sciences. When systems evolve we are interested in the way they change, to predict, support, or react to their evolution. Graph transformation combines the idea of graphs as a universal modelling paradigm with a rule-based approach to specify their evolution. The area is concerned with both the theory of graph transformation and their application to a variety of domains. The conference aims at bringing together researchers and practitioners interested in the foundations and applications of graph transformation to a variety of areas. Topics of interest include, but are not limited to: * Foundations and theory of o General models of graph transformation o High-level and adhesive replacement systems o Node-, edge-, and hyperedge replacement grammars o Parallel, concurrent, and distributed graph transformations o Term graph rewriting o Hierarchical graphs and decompositions of graphs o Logic expression of graph transformation properties o Graph theoretical properties of graph languages o Geometrical and topological aspects of graph transformation o Automata on graphs and parsing of graph languages o Analysis and verification of graph transformation systems o Structuring and modularization concepts for transformation systems o Graph transformation and Petri nets * Application to, languages and tool support for o Software architecture o Workflow and business processes o Software quality and testing o Software evolution o Access control and security models o Aspect-oriented development o Model-driven development, especially model transformations o Domain-specific languages o Implementation of programming languages o Bioinformatics and system biology o Natural computing o Image generation and pattern recognition techniques o Massively parallel computing o Self-adaptive systems and ubiquitous computing o Service-oriented applications and semantic web o Rule- and knowledge-based system

What do I need? A resource-based perspective on visual communication and interaction

Any transformation process results from, and in, the use, production, consumption and transformation of some resources. Interaction processes are no exception to this, but the identification of the involved resources may present some challenges, as many of them are of an immaterial nature. In particular, when communication between a computer software and a human user occurs through the visual channel, the resources to be considered are not only the physical devices through which users manipulate and/or observe the state of the interaction, but also, for example, visual symbols at the interaction surface (as well as the available working space for drawing new symbols), data structures within the computing system (as in principle the whole state of the system might be relevant to the production of a system response), mental representations within the user’s mind (but possibly also levels of attention and tiredness depending on the overall state of the user), etc. Most importantly, the appropriate relations among all of these resources have to be maintained along a whole interaction. When Web-based multimedia or multimodal interaction is considered, new phenomena occur, as the temporal dimension of the interaction acquires relevance and configurations of resources may change due to events external to the interaction proper, as for example changes in bandwidth availability. These sources of complexity in the design of interactive systems are usually tackled by producing local models associated with the various viewpoints, usually expressed via different notations, as adopted in the communities to which stakeholders belong. If these viewpoints and models are not reconciled through proper systematic and formal methods, designs incur the risk of mismatches between the intended and the actual usages of the system, or effects of an interaction. The seminar will explore this arc of problems and some approaches to their solution, and will propose a unifying perspective for the resource-aware design of interactive systems and for the modelling of phenomena related to visual interaction