A Smart Contract-based BPMN Choreography Execution for Management of Construction Processes

Construction management can be grouped into two different levels: strategic early planning, that provides the baseline for project monitoring, and short time initiatives, based on objectives and self-organization from actors who are involved in on-site processes. The latter can be considered as a complex system management issue since it presents emergent behaviors thus it can not be handled in a traditional way. The passage from project scheduling to on site operations management requires a change of perspective. On site short time planning is a process of forecasting future outcomes therefore it deals with uncertainty and indeterminacy. At present this is managed through the representation of many separate orchestrations and this does not allow to eliminate the inefficiencies that arise at the level of synchronization of the individual tasks performed by organizations with contractually separate management. Efficiency in construction management implies to take into consideration choreographies because they better reflect synchronization of different organizations management processes. On the other hand, information processed as a trigger for distributed activities on different management does not guarantee process traceability while smart contracts linked to single task execution assure both promptness and irreversible tracking at single task level. The actual execution of the processes depends both on what happens and on the information that flows between the subjects who actually carry out processes asynchronous to each other, so the only possibility to synchronize them is information. This research aims to describe a framework for applying BPMN choreographies to construction site processes in order to better modeling processes for smart contracts application. The choice of applying BPMN instead of CPM lays in the fact that it allows to model the information flows as well as the preparatory aspects and in addition it allows to represent decision-making moments. Every single activity in the baseline can be modelled as a choreography at a lower level. On the other hand, process performance monitoring can be performed thanks to blockchain tasks notarization. Concrete casting quality assessment process has been chosen as use case. BPMN choreography of this process has been modelled and blockchain application for tasks and information notarization has been development and tested on a construction site

Verifying temporal specifications of Java programs

Many Java programs encode temporal behaviors in their source code, typically mixing three features provided by the Java language: (1) pausing the execution for a limited amount of time, (2) waiting for an event that has to occur before a deadline expires, and (3) comparing timestamps. In this work, we show how to exploit modern SMT solvers together with static analysis in order to produce a network of timed automata approximating the temporal behavior of a set of Java threads. We also prove that the presented abstraction preserves the truth of MTL and ATCTL formulae, two well-known logics for expressing timed specifications. As far as we know, this is the first feasible approach enabling the user to automatically model check timed specifications of Java software directly from the source code

Enhancing BIM through Mixed Reality for Facility Management

Implementation of processes in facility management asks for coordination and collaboration among several factors, each implementing its own sub-process. This goal must cope with several challenges caused by the fragmentation of the AEC (architectural, engineering, construction) industry. In the specific case of facility recommissioning, further constraints are determined by limitations posed by the current status of the existing facility whose knowledge is often limited to coarse preliminary surveys. In this chapter, the benefits determined by the integration between BIM and mixed reality will be presented, along with a prototypical platform that realizes an efficient, distributed collaborative workflow enabling asynchronous collaboration among members of the facility management office, the owner, the design team and technical specialists that may be appointed in recommissioning workflows. Technically, this approach provides an immersive mixed-reality environment capable of seamlessly displaying project information, through which specialists can evaluate and refine different recommissioning options. In addition, the platform supports on-site enrichment of BIM models for a facilitated, yet asynchronous, collaboration between remote and on-site users. This technology was validated by means of real-life experiments regarding a hypothetical recommissioning project of the Construction Division of the DICEA Department at Università Politecnica delle Marche (Ancona, Italy)

Automatic repair of timestamp comparisons

Automated program repair has the potential to reduce the developers’ effort to fix errors in their code. In particular, modern programming languages, such as Java, C, and C#, represent time as integer variables that suffer from integer overflow, introducing subtle errors that are hard to discover and repair. Recent researches on automated program repair rely on test cases to discover failures to correct, making them suitable only for regression errors. We propose a new strategy to automatically repair programs that suffer from timestamp overflows that are manifested in comparison expressions. It unifies the benefits of static analysis and automatic program repair avoiding to depend on testing to identify and correct defected code. Our approach performs an abstract analysis over the time domain of a program using a Time Type System to identify the problematic comparison expressions. The repairing strategy rewrites the timestamp comparisons exploiting the binary representation of machine numbers to correct the code. We have validated the applicability of our approach with 20 open source Java projects. The results show that it is able to correctly repair all 246 identified errors. Furthermore, several patches for three open source projects have been acknowledged and accepted by their developers

Modeling time in Java programs for automatic error detection

Modern programming languages, such as Java, represent time as integer variables, called timestamps. Timestamps allow developers to tacitly model incorrect time values resulting in a program failure because any negative value or every positive value is not necessarily a valid time representation. Current approaches to automatically detect errors in programs, such as Randoop and FindBugs, cannot detect such errors because they treat timestamps as normal integer variables and test them with random values verifying if the program throws an exception. In this paper, we present an approach that considers the time semantics of the Java language to systematically detect time related errors in Java programs. With the formal time semantics, our approach determines which integer variables handle time and which statements use or alter their values. Based on this information, it translates these statements into an SMT model that is passed to an SMT solver. The solver formally verifies the correctness of the model and reports the violations of time properties in that program. For the evaluation, we have implemented our approach in a prototype tool and applied it to the source code of 20 Java open source projects. The results show that our approach is scalable and it is capable of detecting time errors precisely enough allowing its usability in real-world applications

Formal methods for practical reverse engineering and software verification

Software development processes are committed at producing high quality software system. Traditionally, this goal is reached through systematic testing. This thesis project analyzes the possibility of applying mathematical logic and so-called formal methods into the software development process. In fact software testing has two major limitations with respect to verification by means of software testing: every test can show correctness for one possible behavior, while formal methods verification shows that correctness, if proved, holds for all the executions of the system. Furthermore, testing can be used to stress the system implementation, while formal verification can be done also during earlier stages of software development, when abstract models of the system are first sketched. In this work we present an integrated working environment that aims at guiding the software engineer along some of the most relevant moments of a software system lifetime: its development, its verification, its maintenance up to a complete re-structuring. The core of the proposed environment is the language XAL , a parametric extension of the theory of networks of timed automata. After defining its syntax and semantics, we show a novel cutoff theorem for it, proving that systems that are both parametric and timed can be model checked. We then describe two methodologies: the former helps in restructuring existing applications using XAL , extracting parameterized finite-state models from legacy code. The latter is about conducting a formal verification using XAL and its cutoff theorem, if needed. A few case-studies are described that uses the proposed language and methodologies. These case-studies are real-world software systems analyzed in a joint effort with Computer VAR ITT and BINT, two Italian ITC companies

Project Information Model resulting from the on-site survey

The On-site Analysis and Verification Service (ODAVS) is a service developed within the Encore project. It allows users to check any constructability issues regarding renovation projects of residential buildings by means of surveys facilitated by a mixed reality tool. This dataset includes two IFC files of the renovation studies developed by Univpm and JEA (both partners of Encore project) at JEA experimental building in Caceres, and assessed on-site on 2021 December 14th and 15th. The dataset also includes an XML file containing the list of 33 URLS pointing to audio files previously published on a different Zenodo dataset [1]. Note that the access to the Zenodo dataset [1] is restricted. The interested users must ask the dataset authors for permission to access the dataset itself. In the XML file, for each comment, the GUID of the IFC object referred by the audio comment itself is given

Combining Blockchain and BPMN Choreographies for Construction Management

Blockchain is considered a key technology of the current digital revolution and its application is spreading from cryptocurrencies to disparate processes requiring notarization. The well-known independence and contraposition of stakeholders in the AECO sector made DLT applications the hoped-for means to trust each other. Construction site management due to its complexity and the pluralism of the actors involved can be modelled as a BPMN coreography of intra-organizational processes. This aims of the work here presented is the exploitation of blockchains and smart contracts as tools to notarize the state of each intra-organizational process and to enforce compliance with the choreograph

A modular environment for software development and re-engineering

Traditional software development processes are designed to deal with the construction of new software systems. We believe the software development methodologies should include from the beginning the possibility of a re-engineering phase. With our work we identify the main characteristics that make software (re)engineering tools useful and usable Developing them in a modular architecture allows for a better integration with the developer’s working habits