494 research outputs found
Ten virtues of structured graphs
This paper extends the invited talk by the first author about the virtues
of structured graphs. The motivation behind the talk and this paper relies on our
experience on the development of ADR, a formal approach for the design of styleconformant,
reconfigurable software systems. ADR is based on hierarchical graphs
with interfaces and it has been conceived in the attempt of reconciling software architectures
and process calculi by means of graphical methods. We have tried to
write an ADR agnostic paper where we raise some drawbacks of flat, unstructured
graphs for the design and analysis of software systems and we argue that hierarchical,
structured graphs can alleviate such drawbacks
An Algebra of Hierarchical Graphs and its Application to Structural Encoding
We define an algebraic theory of hierarchical graphs, whose axioms
characterise graph isomorphism: two terms are equated exactly when
they represent the same graph. Our algebra can be understood as
a high-level language for describing graphs with a node-sharing, embedding
structure, and it is then well suited for defining graphical
representations of software models where nesting and linking are key
aspects. In particular, we propose the use of our graph formalism as a
convenient way to describe configurations in process calculi equipped
with inherently hierarchical features such as sessions, locations, transactions,
membranes or ambients. The graph syntax can be seen as an
intermediate representation language, that facilitates the encodings of
algebraic specifications, since it provides primitives for nesting, name
restriction and parallel composition. In addition, proving soundness
and correctness of an encoding (i.e. proving that structurally equivalent
processes are mapped to isomorphic graphs) becomes easier as it can
be done by induction over the graph syntax
Constraint Design Rewriting
We propose an algebraic approach to the design and transformation of constraint networks, inspired by Architectural Design Rewriting. The approach can be understood as (i) an extension of ADR with constraints, and (ii) an application of ADR to the design of reconfigurable constraint networks. The main idea is to consider classes of constraint networks as algebras whose operators are used to denote constraint networks with terms. Constraint network transformations such as constraint propagations are specified with rewrite rules exploiting the network’s structure provided by terms
Phenomenology of Unified Dark Matter models with fast transition
A fast transition between a standard matter-like era and a late
CDM-like epoch generated by a single Unified Dark Matter component can
explain the observed acceleration of the Universe. UDM models with a fast
transition should be clearly distinguishable from CDM (and
alternatives) through observations. Here we focus on a particularly simple
model and analyse its viability by studying features of the background model
and properties of the adiabatic UDM perturbations.Comment: 4 pages, 1 figure, Proceedings of the Spanish Relativity Meeting
ERE2012, University of Minho, Guimar\~aes, Portugal, September 3-7, 201
Architectural design rewriting as an architecture description language
Architectural Design Rewriting (ADR) is a declarative rule-based approach for the design of dynamic software architectures. The key features that make ADR a suitable and expressive framework are the algebraic presentation of graph-based structures and the use of conditional rewrite rules. These features enable the modelling of, e.g. hierarchical design, inductively defined reconfigurations and
ordinary computation. Here, we promote ADR as an Architectural
Description Language
Memory Based Online Learning of Deep Representations from Video Streams
We present a novel online unsupervised method for face identity learning from
video streams. The method exploits deep face descriptors together with a memory
based learning mechanism that takes advantage of the temporal coherence of
visual data. Specifically, we introduce a discriminative feature matching
solution based on Reverse Nearest Neighbour and a feature forgetting strategy
that detect redundant features and discard them appropriately while time
progresses. It is shown that the proposed learning procedure is asymptotically
stable and can be effectively used in relevant applications like multiple face
identification and tracking from unconstrained video streams. Experimental
results show that the proposed method achieves comparable results in the task
of multiple face tracking and better performance in face identification with
offline approaches exploiting future information. Code will be publicly
available.Comment: arXiv admin note: text overlap with arXiv:1708.0361
Style-Based architectural reconfigurations
We introduce Architectural Design Rewriting (ADR), an approach to the design of reconfigurable software architectures whose key features are: (i) rule-based approach (over graphs); (ii) hierarchical design; (iii) algebraic presentation; and (iv) inductively-defined reconfigurations. Architectures are modelled by graphs whose edges and nodes represent components and connection ports. Architectures are designed hierarchically by a set of edge replacement rules that fix the architectural style. Depending on their reading, productions allow: (i) top-down design by refinement, (ii) bottom-up typing of actual architectures, and (iii) well-formed composition of architectures. The key idea is to encode style proofs as terms and to exploit such information at run-time for guiding reconfigurations. The main advantages of ADR
are that: (i) instead of reasoning on flat architectures, ADR specifications provide a convenient hierarchical structure, by exploiting the architectural classes introduced by the style, (ii) complex reconfiguration schemes can be defined inductively, and (iii) style-preservation is guaranteed
ILP-based approaches to partitioning recurrent workloads upon heterogeneous multiprocessors
The problem of partitioning systems of independent constrained-deadline sporadic tasks upon heterogeneous multiprocessor platforms is considered. Several different integer linear program (ILP) formulations of this problem, offering different tradeoffs between effectiveness (as quantified by speedup bound) and running time efficiency, are presented
Pompei resiliente AD 2030
Workshop organizzato dal MiBACT e dal CNR in collaborazione con Capgeminì dal titolo “Pompei resiliente AD 2030 – Insight Session”.
L’Insight Session è consistito in un Workshop di una giornata: un laboratorio esperienziale e un momento di collaborazione operativa su temi concreti nel quale ogni partecipante è chiamato a dare il proprio contributo per il raggiungimento di un obiettivo comune.
L’Insight Session è stato un momento per condividere lo stato di avanzamento delle progettualità che coinvolgono attualmente Pompei e per immaginare insieme il percorso verso un modello di smart and resilient archaeological park nel segno dell’innovazione tecnologica, sociale e dello sviluppo territoriale
Linee guida per operazioni con Sistema Aeromobile a Pilotaggio Remoto (SAPR) in aree archeologiche - Parco archeologico di Pompei
Scopo del documento è presentare le linee guida per lo svolgimento delle operazioni con SAPR all’interno di
aree di notevole interesse archeologico, impiegando i vantaggi di questa tecnologia allo scopo di arricchire il
livello di conoscenza e di tutela dei siti.
Tale attività richiede, per contenere i rischi legati alla tipologia di operazione, l’introduzione di specifiche regole
e procedure che l’Operatore SAPR deve rispettare per preservare i livelli di
sicurezza richiesti sia in termini di security (protezione da atti illeciti) che di safety (sicurezza operativa.
Il documento descrive:
-le modalità di richiesta di accesso al sito archeologico per l’esecuzione di operazioni con SAPR
-le limitazioni che l’Operatore SAPR deve rispettare
-le procedure
- …