Ferruccio Damiani - Academia.edu (original) (raw)

Papers by Ferruccio Damiani

Swarm Intelligence

Swarm intelligence leverages collective behaviours emerging from interaction and activity of seve... more Swarm intelligence leverages collective behaviours emerging from interaction and activity of several “simple” agents to solve problems in various environments. One problem of interest in large swarms featuring a variety of sub-goals is swarm clustering, where the individuals of a swarm are assigned or choose to belong to zero or more groups, also called clusters. In this work, we address the sensing-based swarm clustering problem, where clusters are defined based on both the values sensed from the environment and the spatial distribution of the values and the agents. Moreover, we address it in a setting characterised by decentralisation of computation and interaction, and dynamicity of values and mobility of agents. For the solution, we propose to use the field-based computing paradigm, where computation and interaction are expressed in terms of a functional manipulation of fields, distributed and evolving data structures mapping each individual of the system to values over time. We...

One of the key applications of physically-deployed multi-agent systems, such as mobile robots, dr... more One of the key applications of physically-deployed multi-agent systems, such as mobile robots, drones, or personal agents in human mobility scenarios, is to promote a pervasive notion of distributed sensing achieved by strict agent cooperation. A quintessential operation of distributed sensing is data summarisation over a region of space, which finds many applications in variations of counting problems: Counting items, measuring space, averaging environmental values, and so on. A typical strategy to perform peer-to-peer data summarisation with local interactions is to progressively accumulate information towards one or more collector agents, though this typically exhibits several sources of fragility, especially in scenarios featuring high mobility. In this paper, we introduce a new multi-agent algorithm for dynamic summarisation of distributed data, called parametric weighted multi-path, based on a local strategy to break, send, and then re-combine sensed data across neighbours bas...

Recent work in the area of coordination models and collective adaptive systems promotes a view of... more Recent work in the area of coordination models and collective adaptive systems promotes a view of distributed computations as functions manipulating computational fields (data structures spread over space and evolving over time), and introduces the field calculus as a formal foundation for field computations. With the field calculus, evolution (time) and neighbor interaction (space) are handled by separate functional operators: however, this intrinsically limits the speed of information propagation that can be achieved by their combined use. In this paper, we propose a new field-based coordination operator called share, which captures the space-time nature of field computations in a single operator that declaratively achieves: (i) observation of neighbors’ values; (ii) reduction to a single local value; and (iii) update and converse sharing to neighbors of a local variable. In addition to conceptual economy, use of the share operator also allows many prior field calculus algorithms ...

Systematic reuse of software artifacts can be achieved with software product lines, which represe... more Systematic reuse of software artifacts can be achieved with software product lines, which represent a family of similar software systems. A variability model, e.g., feature model, describes their commonalities and variabilities and serves as a basis for a product configuration, i.e., the selection of features according to constraints defined in the model. These variability models can contain additional information, such as attributes, which enrich features with typed values for various purposes (e.g., optimization, simplified readability). Typically, these attributes are not directly reusable in code artifacts as the variability model is only used to assemble or change code artifacts according to a product configuration. Furthermore, there are many languages for implementing software product lines such as DeltaJ which do not support the direct propagation of feature attributes to the associated code artifacts. In this paper, we present parametric DeltaJ, an adaptation of the program...

2018 IEEE Real-Time Systems Symposium (RTSS), 2018

A Software Product Line (SPL) is a set of similar programs, called variants, with a common code b... more A Software Product Line (SPL) is a set of similar programs, called variants, with a common code base and well documented variability. Because the number of variants in an SPL can be large, checking them efficiently (e.g., to ensure that they are all well-typed) is a challenging problem. Delta-Oriented Programming (DOP) is a flexible approach to implement SPLs. The Abstract Behavioral Specification (ABS) modeling language and toolchain supports delta-oriented SPLs. In this paper we present an extension of the ABS toolchain with a mechanism for checking that all the variants of an SPL can be generated and are well-typed ABS programs. Currently we have implemented only part of this mechanism: our implementation (integrated in version 1.4.2 of the ABS toolchain and released in April 2017) checks whether all variants can be generated, however it does not check, in particular, whether the bodies of the methods are well-typed. Empirical evaluation shows that the current implementation allo...

Software-intensive systems can have thousands of interdependent configuration options across diff... more Software-intensive systems can have thousands of interdependent configuration options across different subsystems. Feature models allow designers to organize the configuration space by describing configuration options using interdependent features: a feature is a name representing some functionality and each software variant is identified by a set of features. Different representations of feature models have been proposed in the literature. In this paper we focus on the propositional representation (which works well in practice) and the extensional representation (which has been recently shown well suited for theoretical investigations). We provide an algebraic and a propositional characterization of feature model operations and relations, and we formalize the connection between the two characterizations as monomorphisms from lattices of propositional feature models to lattices of extensional features models. This formalization sheds new light on the correspondence between the extensional and the propositional representations of feature models. It aims to foster the development of a formal framework for supporting practical exploitation of future theoretical developments on feature models and software product lines.

Log. Methods Comput. Sci., 2020

Field-based coordination has been proposed as a model for coordinating collective adaptive system... more Field-based coordination has been proposed as a model for coordinating collective adaptive systems, promoting a view of distributed computations as functions manipulating data structures spread over space and evolving over time, called computational fields. The field calculus is a formal foundation for field computations, providing specific constructs for evolution (time) and neighbor interaction (space), which are handled by separate operators (called rep and nbr, respectively). This approach, however, intrinsically limits the speed of information propagation that can be achieved by their combined use. In this paper, we propose a new field-based coordination operator called share, which captures the space-time nature of field computations in a single operator that declaratively achieves: (i) observation of neighbors' values; (ii) reduction to a single local value; and iii) update and converse sharing to neighbors of a local variable. We show that for an important class of self-...

A Software Product Line (SPL) is a family of similar programs (called variants) generated from a ... more A Software Product Line (SPL) is a family of similar programs (called variants) generated from a common artifact base. Variability in an SPL can be documented in terms of abstract description of functionalities (called features): a feature model (FM) identifies each variant by a set of features (called a product). Delta-orientation is a flexible approach to implement SPLs. An SPL Signature (SPLS) is a variability-aware Application Programming Interface (API), i.e., an SPL where each variant is the API of a program. In this paper we introduce and formalize the notion of slice of an SPLS K for a set of features F, i.e., an SPLS obtained from by K by hiding the features that are not in F. Moreover, we introduce the problem of defining an efficient algorithm that, given a delta-oriented SPLS K and a set of features F, returns a delta-oriented SPLS that is an slice of K for F. The proposed notions are formalized for SPLs of programs written in an imperative version of Featherweight Java.

ArXiv, 2020

Recent works in contexts like the Internet of Things (IoT) and large-scale Cyber-Physical Systems... more Recent works in contexts like the Internet of Things (IoT) and large-scale Cyber-Physical Systems (CPS) propose the idea of programming distributed systems by focussing on their global behaviour across space and time. In this view, a potentially vast and heterogeneous set of devices is considered as an "aggregate" to be programmed as a whole, while abstracting away the details of individual behaviour and exchange of messages, which are expressed declaratively. One such a paradigm, known as aggregate programming, builds on computational models inspired by field-based coordination. Existing models such as the field calculus capture interaction with neighbours by a so-called "neighbouring field" (a map from neighbours to values). This requires ad-hoc mechanisms to smoothly compose with standard values, thus complicating programming and introducing clutter in aggregate programs, libraries and domain-specific languages (DSLs). To address this key issue we introduce th...

Modal transition systems (MTSs) and featured transition systems (FTSs) are widely recognised as f... more Modal transition systems (MTSs) and featured transition systems (FTSs) are widely recognised as fundamental behavioural models for software product lines. This short paper summarises the contributions published in [3]: MTSs with variability constraints (MTS\(\upsilon \)s) are equally expressive as FTSs. This is proved by giving sound and complete transformations of the latter into the former, and of the former into the latter. The benefits of this result are twofold. First, it contributes to the expressiveness hierarchy of such basic models studied in the literature. Second, it provides an automatic algorithm from FTSs to MTS\(\upsilon \)s that preserves the original (compact) branching structure, thus paving the way for model checking FTSs with the variability model checker VMC.

Proceedings of the ACM/IEEE 42nd International Conference on Software Engineering, 2020

Highly-configurable software systems can have thousands of interdependent configuration options a... more Highly-configurable software systems can have thousands of interdependent configuration options across different subsystems. In the resulting configuration space, discovering a valid product configuration for some selected options can be complex and error prone. The configuration space can be organized using a feature model, fragmented into smaller interdependent feature models reflecting the configuration options of each subsystem. We propose a method for lazy product discovery in large fragmented feature models with interdependent features. We formalize the method and prove its soundness and completeness. The evaluation explores an industrial-size configuration space. The results show that lazy product discovery has significant performance benefits compared to standard product discovery, which in contrast to our method requires all fragments to be composed to analyze the feature model. Furthermore, the method succeeds when more efficient, heuristics-based engines fail to find a valid configuration. CCS CONCEPTS • Software and its engineering → Software product lines; Feature interaction; Abstraction, modeling and modularity; Software libraries and repositories; Software creation and management;

Theoretical Aspects of Computing – ICTAC 2020, 2020

Proceedings of the 25th ACM International Systems and Software Product Line Conference - Volume A, 2021

VMC is a research tool for model checking variability-rich behavioural models specified as a moda... more VMC is a research tool for model checking variability-rich behavioural models specified as a modal transition system (MTS) with variability constraints (MTSυ). In this tutorial, we introduce a tool chain built on VMC that allows to perform an efficient kind of family-based model checking in absence of deadlocks. It accepts as input either an MTSυ or a featured transition system (FTS). CCS CONCEPTS • Software and its engineering → Software product lines; Formal methods; Model checking; Automated static analysis.

Proceedings of the 23rd International Systems and Software Product Line Conference - Volume A, 2019

A Featured Transition System (FTS) is a formal behavioural model for software product lines, whic... more A Featured Transition System (FTS) is a formal behavioural model for software product lines, which represents the behaviour of all the products of an SPL in a single compact structure by associating transitions with features that condition their existence in products. In general, an FTS may contain featured transitions that are unreachable in any product (so called dead transitions) or, on the contrary, mandatorily present in all products for which their source state is reachable (so called false optional transitions), as well as states from which only for certain products progress is possible (so called hidden deadlocks). In this paper, we provide algorithms to analyse an FTS for such ambiguities and to transform an ambiguous FTS into an unambiguous FTS. The scope of our approach is twofold. First and foremost, an ambiguous model is typically undesired as it gives an unclear idea of the SPL. Second, an unambiguous FTS paves the way for efficient family-based model checking. We apply our approach to illustrative examples from the literature. CCS CONCEPTS • Software and its engineering → Specification languages; Formal methods; Software product lines.

Fundamental Approaches to Software Engineering, 2017

This paper presents a unified model for two complementary approaches of code reuse: Traits and De... more This paper presents a unified model for two complementary approaches of code reuse: Traits and Delta-Oriented Programming (DOP). Traits are used to modularly construct classes, while DOP is a modular approach to construct Software Product Lines. In this paper, we identify the common structure of these two approaches, present a core calculus that combine Traits and DOP in a unified framework, provide an implementation for the ABS modelling language, and illustrate its application in an industrial modeling scenario. This work has been partially supported by: EU Horizon 2020 project HyVar (www.hyvar-project.eu), GA No. 644298; ICT COST Action IC1402 ARVI (www.cost-arvi.eu); Ateneo/CSP D16D15000360005 project RunVar (runvar-project.di.unito.it); project FormbaR (formbar.raillab.de), Innovationsallianz TU Darmstadt-Deutsche Bahn Netz AG.

Proceedings of the 13th European Conference on Software Architecture - ECSA '19 - volume 2, 2019

We advocate a novel concept of dependable intelligent edge systems (DIES) i.e., the edge systems ... more We advocate a novel concept of dependable intelligent edge systems (DIES) i.e., the edge systems ensuring a high degree of dependability (e.g., security, safety, and robustness) and autonomy because of their applications in critical domains. Building DIES entail a paradigm shift in architectures for acquiring, storing, and processing potentially large amounts of complex data: data management is placed at the edge between the data sources and local processing entities, with loose coupling to storage and processing services located in the cloud. As such, the literal definition of edge and intelligence is adopted, i.e., the ability to acquire and apply knowledge and skills is shifted towards the edge of the network, outside the cloud infrastructure. This paradigm shift offers flexibility, auto configuration, and auto diagnosis, but also introduces novel challenges. CCS CONCEPTS • Computing methodologies → Distributed computing methodologies; • Computer systems organization → Distributed architectures; Embedded and cyber-physical systems; • Software and its engineering → Software system structures.

Electronic Proceedings in Theoretical Computer Science, 2018

Collecting statistic from graph-based data is an increasingly studied topic in the data mining co... more Collecting statistic from graph-based data is an increasingly studied topic in the data mining community. We argue that these statistics have great value as well in dynamic IoT contexts: they can support complex computational activities involving distributed coordination and provision of situation recognition. We show that the HyperANF algorithm for calculating the neighbourhood function of vertices of a graph naturally allows for a fully distributed and asynchronous implementation, thanks to a mapping to the field calculus, a distribution model proposed for collective adaptive systems. This mapping gives evidence that the field calculus framework is well-suited to accommodate massively parallel computations over graphs. Furthermore, it provides a new "self-stabilising" building block which can be used in aggregate computing in several contexts, there including improved leader election or network vulnerabilities detection.

Electronic Proceedings in Theoretical Computer Science, 2019

Runtime verification is a computing analysis paradigm based on observing a system at runtime (to ... more Runtime verification is a computing analysis paradigm based on observing a system at runtime (to check its expected behaviour) by means of monitors generated from formal specifications. Distributed runtime verification is runtime verification in connection with distributed systems: it comprises both monitoring of distributed systems and using distributed systems for monitoring. Aggregate computing is a programming paradigm based on a reference computing machine that is the aggregate collection of devices that cooperatively carry out a computational process: the details of behaviour, position and number of devices are largely abstracted away, to be replaced with a spacefilling computational environment. In this position paper we argue, by means of simple examples, that aggregate computing is particularly well suited for implementing distributed monitors. Our aim is to foster further research on how to generate aggregate computing monitors from suitable formal specifications.

ACM Transactions on Computational Logic, 2019

The complexity of large-scale distributed systems, particularly when deployed in physical space, ... more The complexity of large-scale distributed systems, particularly when deployed in physical space, calls for new mechanisms to address composability and reusability of collective adaptive behaviour. Computational fields have been proposed as an effective abstraction to fill the gap between the macro-level of such systems (specifying a system’s collective behaviour) and the micro-level (individual devices’ actions of computation and interaction to implement that collective specification), thereby providing a basis to better facilitate the engineering of collective APIs and complex systems at higher levels of abstraction. This article proposes a full formal foundation for field computations, in terms of a core (higher-order) calculus of computational fields containing a few key syntactic constructs, and equipped with typing, denotational and operational semantics. Critically, this allows formal establishment of a link between the micro- and macro-levels of collective adaptive systems by...