Michel S. Soares

User requirements modeling and analysis of software-intensive systems

The increasing complexity of software systems makes Requirements Engineering activities both more important and more difficult. This article is about user requirements development, mainly the activities of documenting and analyzing user requirements for software-intensive systems. These are modeling activities that are useful for further Requirements Engineering activities. Current techniques for requirements modeling present a number of problems and limitations. Based on these shortcomings, a list of requirements for requirements modeling languages is proposed. The proposal of this article is to show how some extensions to SysML diagrams and tables can fulfill most of these requirements. The approach is illustrated by a list of user requirements for a Road Traffic Management System.

Application of an Extended SysML Requirements Diagram to Model Real-Time Control Systems

Most techniques for modeling requirements present many problems and limitations, including modeling requirements at a single level of abstraction, and are specific to model functional requirements. The objective of this article is to perform a study on modeling requirements of Real-Time Systems through an extension of the SysML Requirements Diagram focusing on the traceability of non-functional and functional requirements. The proposed approach has demonstrated to be effective for representing software requirements of real-time systems at multiple levels of abstraction and classification. The proposed metamodel represents concisely the traceability of requirements in a high abstraction level.

A 15-year follow-up study on schistosomiasis in a low-endemic area in Rio de Janeiro State, Brazil.

Fifteen years after our first investigation, a follow-up study was carried out with the purpose of assessing the evolution of schistosomiasis in the locality of Sabugo, Paracambi, state of Rio de Janeiro, Brazil, an area with low prevalence of the disease. The coprological techniques adopted were spontaneous sedimentation and Kato-Katz. Out of the 1356 individuals assessed, 13 (1%) were infected with Schistosoma mansoni. From those, 10 were males, 12 were over 15 years old, and at least 11 had been infected in Sabugo. All patients presented either the intestinal or the hepato-intestinal form of the disease, and 8 (61.5%) harboured light parasitic loads. In 1990, there were 27 (2.7%) infected individuals; less than half harboured light parasitic loads, with the predominance of moderate and heavy forms. Although our results indicate an improvement in the epidemiological situation of schistosomiasis in Sabugo, transmission of the disease in the locality is still active, especially among young males, and tends to be acquired during leisure activities.

A real-life test bed for multi-agent monitoring of road network performance

This paper describes an approach to road network monitoring. The approach has the following components: a multi-agent hierarchical monitoring system in which the agents are network elements, such as crossings, road segments and routes, software engineering techniques to handle legacy sensors and to homogenize their heterogeneous data streams, distributed Kalman filtering to reduce sensor noise and a traffic simulation model to help in predicting future traffic states and to replace missing physical sensors. The approach has resulted in a real-life test bed for network performance monitoring in which various configurations of agents and various ways of distributed Kalman filtering can be tested. The current, still rather simple monitoring configuration is already in operational use for traffic management.

Model-based requirements specification of real-time systems with UML, SysML and MARTE

Activities of specification, analysis and design of real-time systems (RTS) are highly dependent on an effective understanding of the application domain and on the thorough representation of their basic requirements. Model-based approaches using modeling languages such as UML are often applied to contribute to handle complexity of RTS development. However, UML alone does not completely represent important features associated with these systems, such as relationship with hardware elements and an effective representation of timing constraints. This article explores the combined use of UML and its profiles SysML and MARTE for modeling hardware and software requirements of RTS, with application to a case of controlling urban road traffic. The SysML profile alone does not present the representation of temporal, behavioral and performance requirements. The MARTE profile provides key resources to specify non-functional requirements for RTS, in addition to a clear description of the various relevant aspects of requirements definition of RTS, as for instance, temporal aspects and constraints. The main objective is to present the combined application of SysML with MARTE stereotypes, which enables the specification of different features of individual software requirements. Thus, in addition to the factors mentioned above, we can say that the proposed approach has an important role to specify RTS at different levels of detail and levels of abstraction.

Extensions of SysML for Modeling an Aspect Oriented Software Architecture with Multiple Views

Aspect-oriented programming was proposed in order to handle crosscutting concerns in an efficient way. Initial proposals in this field were applied to source code. Later on, aspects were considered to be applied in other phases of software development, such as within software architecture. There are several advantages in identifying aspects at the architectural level such as reducing costs of software maintenance and preserving the notion of aspects in the development process ensuring traceability. Whereas different stakeholders need to view the system from various perspectives, the proposal of a software architecture in multiple views is essential. Therefore, this article proposes an aspect oriented software architecture model with multiple views to define the structure of aspect oriented software. An extension of the SysML modeling language is applied to model the architectural views.

Multiple-View Architecture Model for Distributed Real-Time Systems Using MARTE

Currently, the object-oriented (OO) paradigm is the most common approach for modeling software systems. This includes object-oriented programming languages, methods, and modeling languages. Among all OO notations, UML (OMG 2010a) is the most used one, despite the many well-known issues observed both in theory and practice, such as ambiguity (Beneken et al. 2003) and lack of defined semantics (Andre et al. 2007, Dobing and Parsons 2006).

A Framework for Multi-layered Requirements Documentation and Analysis

The complexity of current software-intensive systems must be tackled during all phases of the system life cycle. Requirements Engineering is considered both by practitioners and researchers a crucial phase of software development. This article tackles requirements complexity by proposing a framework to document and analyze requirements at different levels of detail, inspired by the layered style of software architecture. Therefore, separation of concerns, an important concept used for software design, is applied in the context of requirements documentation and analysis. The framework has been applied in practice to design software-intensive systems in many domains. Specifically for this article, the proposal is to apply the framework to document and to analyze requirements for road traffic management systems.

Interactive web interfaces modeling, simulation and analysis using Colored Petri Nets

Interaction modeling is a relevant activity during software development processes. Created relying on Petri Nets theory and aiming to represent discrete time events, Colored Petri Nets (CPNs) are a graphical formal language developed and widely employed for system modeling. While traditional CPNs only have elements with ordinary stylization and behaviors, in this article we explore the key ideas behind Web Interaction Modeling Using Colored Petri Nets (wiCPN), a modeling style developed with focus on representing Web interactions as an incremental improvement of CPNs. We review wiCPN’s refinements over CPNs and the modeling of the Web interface of Classroom eXperience (CX), a ubiquitous educational platform, thus verifying the model’s properties to ensure it was able to represent the different access levels among its users and how wiCPN displayed suitability to comprehend this requirement on the generated model. We have also improved the originally developed model with the modification of elements to make it finite and fully analyzable. Also, we added temporization capabilities to the model and ran corresponding user simulation to observe the average time that users with different roles tend to spend during interactions. We compared wiCPN results with Unified Modeling Language (UML) Activity and Use Case diagrams, observing, as outcomes, that the generated model represented CX’s interactive flow correctly and maintained a concise notation—a single wiCPN diagram was sufficient to depict the same interactive flow that, in UML, would require several diagrams, something that could overload the design team in actual software development scenarios. We also included new user experiments comprising qualitative results from experts. Finally, we created a reachability graph for the new model and generated a full state space report, analyzing Petri Nets properties such as boundedness, liveness and home marking.

A Multi-Criteria Analysis of Techniques and Tools for Tracing Software Requirements

Changes in requirements occur throughout the software process from elicitation and analysis requirements through the operation of the software. Requirements traceability makes it possible to identify the origin and the dependence of the software requirements. Studies show that the tools and current requirements traceability methods are inadequate and hamper the practical use of traceability. In this paper, we carried out analysis of evaluation techniques and requirement traceability tools in order to verify if the techniques are being actually used and are being supported by software tools. As a result, we observed the lack of relationship between the techniques and tools evaluated and that some criteria, such as communication with stakeholders, difficulty, and requirement of stability were little considered in the evaluated tools.