Giuseppe De Ruvo

An Eclipse-Based Editor to Support LOTOS Newcomers

We present ELOTON, an Eclipse-based Editor to help people who want to approach the Language of Temporal Ordering Specification (LOTOS). LOTOS is a Formal Description Technique standardized by ISO for the design of concurrent and distributed systems, and in particular for OSI services and protocols. LOTOS has been widely used for the specification of large data communication systems. It is mathematically well-defined and expressive: it allows concurrency, non-determinism, synchronous and asynchronous communications. CADP is a popular toolbox that supports high-level descriptions written in LOTOS, among others. Unluckily, there not exists an user interface suitable for newcomers in formal methods. Thus, many people encounter many obstacles in using formal methods and in particular model checking due to the lacking of user-friendly tools. We argue that ELOTON, thanks to its rich text editor and visualization features might involve a major number of users coming from various disciplines. Our tool serves as a graphical front-end for CADP.

A Novel Methodology Based on Formal Methods for Analysis and Verification of Wikis

A wiki is a collaborative Web site whose content can be edited by anyone who has access to it. Wikis are becoming a new work tool in enterprises and are widely spreading everywhere. In fact, they are often used as internal documentation for various in-house systems and applications. Understanding and maintaining the structure of a wiki may be a crucial aspect. As well as software grows, decays and needs refactoring, the organic growth of a wiki inevitably leads to its degradation. We propose a novel methodology based on formal methods to analyse and verify the architecture of wikis. Formal verification helps to perform refactoring. Each wiki category, a set of wiki pages, is modelled using the Calculus of Communicating Systems (CCS) process algebra in order to verify specific properties. First experiments conducted on a adequate number of categories of Wikipedia, assess the validity of our methodology revealing new directions for future research.

Analysing Wiki Quality Using Probabilistic Model Checking

Wikis delineate a new work tool in enterprises and they are spreading everywhere. Indeed, they are often used as internal documentation for various in-house systems and applications as well as powerful tools for collaboration and knowledge sharing. As occurs with software, the fundamental growth of a wiki may lead to its degradation. The quality of wikis, especially in enterprise contexts, should not play a trivial role. Software quality is a very discussed topic, but there are not many studies regarding the quality of wikis. We propose a probabilistic model to represent wikis and to investigate their quality. Due to the similarity with the World Wide Web it is natural to consider the popular Google PageRank (with minor modifications) to calculate probabilities between pages. Each wiki category, a set of wiki pages, is modelled using the PRISM language in order to verify specific properties in PCTL*. Experiments conducted on a adequate number of (enterprise) wikis assess the validity of our methodology.

Equivalence-Based Selection of Best-Fit Models to Support Wiki Design

A wiki is a collaborative Web site whose content can be edited by anyone who has the access. Wikis are becoming a new work tool in enterprises and are widely spreading every-where. Indeed, it is important to consider the design and evolution of a wiki. We present a methodology to help wiki designers, engineers and domain experts. In practice, from the wikis we derive formal models, which are successively used to perform equivalence checking. More precisely, in order to design a wiki p we propose a methodology for the selection of the best-fit wiki model q, among a set of candidate ones. For best fit we mean that p and q have a similar structure. To handle the complexity of finding all possible candidates processes q, a heuristic function can be used to filter the set of significant candidates, and to speed up the search of a successful one, which is the main contribution of the paper. Eventually, the elected model may be exploited to start the design process.

Integrating Model Driven and Model Checking to Mine Design Patterns

The use of Design Patterns has constantly grown in the development of Object Oriented systems, due to the well-known advantage they offer to improve the quality of software design. However, lack of documentation about which Design Patterns are actually adopted and implemented in the code and about the code components involved in the implementation of each Design Pattern instance can make harder any operation of maintenance, reuse, or evolution impacting those components. Thus, several Design Pattern Mining approaches and tools have been proposed to identify the instances of Design Pattern implemented in an Object oriented system. Nevertheless, the results produced by these approaches can be not fully complete and precise because of the presence of false positive/negative. In this paper we propose to integrate a Model Driven based Design Pattern mining approach with a Formal Method technique to automatically refine and improve the precision of results of traditional mining tool. In particular Model checking is used to refine the results of the Design Pattern Finder (DPF) tool implementing a Model Driven based approach to detect Design Pattern instances Object Oriented systems. To verify and validate the feasibility and effectiveness of the proposed approach we carried out a case study regarding four open source OO systems. The results from the case study showed that actually the technique allowed to raise significantly the precision of the instances that the DPF tool was able to identify.

Model checking to improve precision of design pattern instances identification in OO systems

In the last two decades some methods and tools have been proposed to identify the Design Pattern (DP) instances implemented in an existing Object Oriented (OO) software system. This allows to know which OO components are involved in each DP instance. Such a knowledge is useful to better understand the system thus reducing the effort to modify and evolve it. The results obtained by the existing methods and tools can suffer a lack of completeness or precision due to the presence of false positive/negative. Model Checking (MC) algorithms can be used to improve the precision of DPs instances detected by a tool by automatically refining the results it produces. In this paper a MC based technique is defined and applied to the results of an existing DPs mining tool, called Design Pattern Finder (DPF), to improve the precision by verifying automatically the DPs instances it detects. To verify and assess the feasibility and the effectiveness of the proposed technique, we carried out a case study where it was applied on some open source OO systems. The results showed that the proposed technique allowed to improve the precision of the DPs instances detected by the DPF tool.

An approach for restructuring text content

Software engineers have successfully used Natural Language Processing for refactoring source code. Conversely, in this paper we investigate the possibility to apply software refactoring techniques to textual content. As a procedural program is composed of functions calling each other, a document can be modeled as content fragments connected each other through links. Inspired by software engineering refactoring strategies, we propose an approach for refactoring wiki content. The approach has been applied to the EMF category of Eclipsepedia with encouraging results.

k-Bisimulation: A Bisimulation for Measuring the Dissimilarity Between Processes

We propose to use bisimulation to quantify dissimilarity between processes: in this case we speak of k-bisimulation. Two processes p and q, whose semantics is given through transition systems, are k-bisimilar if they differ from at most k moves, where k is a natural number. Roughly speaking, the k-bisimulation captures the extension of the dissimilarity between p and q when they are neither strong nor weak equivalent. The importance of the formal concept of k-bisimulation can be seen in several application fields, such as clone detection, process mining, business-IT alignment. We propose several heuristics in order to efficiently check such a bisimulation. The approach can be applied to different specification languages CCS, LOTOS, CSP provided that the language semantics is based on the notion of transition system. We have implemented a prototype tool and we have conducted experiments on well-known systems for a proof of concept of our methodology.

Powerful Equivalence Checking in the Bank Supply Process

Equivalence checking is a powerful formal technique to improve the quality of computer and software systems. It is usually employed to verify the correctness in a model-based design. Notwithstanding, a detailed and precise specification is required in order to apply equivalence checking to a given domain. Unfortunately, certain fields of application like business process management lack of such adequate information. We explore the applicability of equivalence checking to validation of Business Processes described by the aid of Workflow Management systems. Due to the state explosion problem, formal methods are not very popular in the business domain. In fact, the state space grows exponentially in the number of concurrent processes leading to an impracticable verification. In this paper we deal with a heuristic-based methodology developed to beat the state explosion problem when checking non-equivalence. Our contribution is two-fold: (i) we show how equivalence checking can successfully operate in the business modelling and analysis context, (ii) we model and use the bank supply process as a real case study to evaluate and test the heuristic-based methodology. We show and debate encouraging experimental results comparing them with a state of the art model checker i.e. CADP. This suggests that the business community, mostly in the banking field, can take advantage from our efficient methodology based on process algebra.