Paulo Cézar Stadzisz

A Brazilian survey on UML and model-driven practices for embedded software development

This paper brings statistical findings from a survey about the use of UML modeling and model-driven approaches for the design of embedded software in Brazil. The survey provides evidences regarding the maturity of use of UML and model-driven approaches, how they are employed, and which and where the professionals who use them are. Technical, organizational, and social aspects were investigated and documented by making use of a descriptive research method. Such aspects seemingly reflect the opinions of software engineers on how they perceive the impact of using UML and model-driven approaches on productivity and quality in embedded software development. Results show that most participants are clearly aware of the modeling approach value, even though they practice it only to a limited degree. Most respondents who make use of model-driven approaches attest that productivity and portability are the key advantages of their use.

Inference Based on Notifications: A Holonic Metamodel Applied to Control Issues

The ability to infer is necessary to achieve desirable behavior within many systems. In software systems, this ability can be achieved through a number of decision-making solutions. This paper proposes an alternative inference solution inspired in rule-based systems (RBSs). This solution considers classical RBS elements, such as rules and fact-base sets, as actual computational entities. The innovative aspect of the proposed solution is that computational entities carry out inference by means of collaborations based upon notifications instead of search methods. The notification approach has advantages, such as high reactivity, easy distribution, and good tradeoff between generality and applicability. The solution consists of a holonic metamodel whose features are highlighted, in this paper, by applying it to a collaborative control of an agile manufacturing system.

Holonic Control Metamodel

Current production leanings, such as high product variability, demand advanced manufacturing systems (MSs). An example is the holonic MS (HMS) in which entities (e.g., resources and products) are ldquosmart.rdquo These entities are called holons (HLs), and their interactions are coordinated by holonic control (HC). Indeed, the complexity of HMS has required new design and test tools. In this context, this paper presents an HC metamodel, which was applied to a particular simulator. In this control solution, causal knowledge is enclosed in Rule HLs, which receive facts about Resource HLs and deliberate about the actions to be executed. The inference happens by means of an innovative net of notifications built from expert knowledge, in the form of (Sub)-HLs, which allows high reactivity, HL decoupling, conflict handling, coherent control expression and execution, and easy control adaptations. This solution still considers other issues, namely, the product-driven manufacturing: a tendency related to customized production in which Product HLs negotiate with Resource HLs aiming at adaptability and reactivity. In this case, Rule HLs intermediate and organize the collaborations of Product HLs and Resource HLs. This paper proposes to use the metamodel to compose a process-driven control and a product-driven control applied to a similar simulated HMS, highlighting their differences and advantages.

NOCA ‑ A Notification-Oriented Computer Architecture

Current software development processes lack techniques for the productive and quality design of software that makes efficient use of the parallel execution capabilities provided by the hardware of modern computing systems. In this context, the Notification Oriented Paradigm (NOP) has been recently developed aiming at a new organization of software logic based on notifications among causal-logical entities. NOP allows exploring the parallelization and/or distribution in a simpler and more efficient way than more commonly used programming paradigms. However, the execution dynamics under the NOP, based on notifications, is not efficiently performed by the hardware of current computing systems. This paper presents a new computer architecture, named NOCA, which is suitable for execution of software developed according to the NOP computing model. NOCA was designed in accordance with the principles of generality and scalability, which allow it to execute NOP software at any level of complexity by fetching it from a program memory. The developed architecture is organized as a fine grain multiprocessor that hierarchically executes instructions through sets of specialized processor cores. Preliminary experiments performed on this architecture show that NOCA presents improvements in terms of performance comparative evaluations.

Notification-Oriented Paradigm Framework 2.0: An Implementation Based On Design Patterns

The Notification-Oriented Paradigm (NOP) is a new technique to develop software. NOP is a rule-oriented approach where every rule and fact-base element is derived into less complex entities with specific tasks. These entities particularly collaborate by means of notifications, which occur only when their state changes. This allows carrying out an inference process completely active. Due to this particular arrangement, NOP can eliminate most of the structural and temporal redundancies that affects program execution performance, difficulties in codification level, and high coupling in program modules. In order to validate the NOP state of art, a framework was initially implemented in C++. Even though it quite demonstrated the features of the paradigm in terms of the development process, it still presented a gap in execution performance. In this context, this paper presents the NOP Framework 2.0. This new version was reengineered aiming better structuration and improvements in the execution time of NOP applications. The experiments show that the new implementation is two times faster than the former one. In addition, new experiments were presented comparing the NOP applications to equivalent implementations based on Oriented-Object Paradigm (OOP) in C++. The NOP applications presented, in some cases, better performance than the OOP applications.

A new Method for Dynamic Balancing of Workload and Scalability in Multicore Systems

This paper presents a new method for dynamic balancing of workload and scalability in multicore systems. This method is called LobeNOI (Load balancing engine for NOI - Notification-Oriented Inference). NOI is composed of a set of small and reactive computational entities, which communicate only when needed by avoiding both temporal and structural redundancies. The innovative aspect of the considered approach would be that computational entities carry out inference by means of collaborations based upon direct notifications. This paper actually presents a way to improve the utilization of hardware processing power available in modern computers, more precisely, in multicore systems, through distribution of NOI entities in multiple cores. The main contributions of the method are the transparency in the concurrent software design process and the better hardware utilization. Moreover, NOI presents itself as a promising alternative to compose complex, distributed and scalable applications.

Notification-Oriented and Rete Network Inference: A Comparative Study

This paper presents a practical and a theoretical comparative study between the so-called Notification-Oriented Inference (NOI) and Rete Network inference. NOI is composed of a network of small computational entities, which communicate only when necessary, avoiding both temporal and structural redundancies in a program inference. The innovative aspect of the considered approach would be that computational entities carry out the inference by means of collaborations based upon direct notifications (reactive inference). This approach differs from usual inference mechanisms of rule-based systems, which are based on checks/searches over passive data. This search based execution is present even on advanced mechanisms such as Rete. In this sense, the focus of this paper is to analyze performance measurements over an experimental application implemented in both mechanisms. Coupling and redundancy problems are also considered in a theoretical analysis. The results show that NOI can perform around 6 times faster than the compiled Rete mechanism and around 20 times faster than the interpreted Rete mechanism in the cases proposed in this paper. Moreover, NOI presents better asymptotic complexity time and decoupling degree, presenting itself as a promising alternative to compose complex, distributed and scalable applications.

Notification-Oriented Paradigm to Implement Digital Hardware

The growing demand for high-performance digital circuits, mainly involving FPGAs, increases the demand for high-level synthesis (HLS) tools. Traditional Hardware Description Languages (HDLs) are complex and depend on low-level abstractions, thereby requiring hardware detailed knowledge from developers. In turn, the current HLS tools are based on proprietary or C/C++ derived languages, which allow easier circuit description but decrease performance. This work presents an alternative solution for designing digital circuits, which arises from the Notification-Oriented Paradigm (NOP). The NOP is an alternative computing solution based upon a set of predefined interconnected entities whose collaborations are performed through precise notifications. The NOP, when targeted to digital hardware (DH), allows the developer to describe the circuit behavior just by connecting and parameterizing elements. The result is a VHDL file that can be compiled for any platform from any manufacturer. In order to check the functionality of this approach, sorting circuits were built both with usual VHDL and with the NOP VHDL aiming to compare the resulting circuits in terms of operating frequency and resource use. The results show that the NOP VHDL approach facilitates the build of digital circuits when compared to the VHDL usual approach without limiting the operating frequency or increasing the use of resources.

A notification-oriented solution for data-intensive enterprise information systems – A cloud manufacturing case

ABSTRACT The application of Industrial Internet of Things (IIoT) has brought a series of new challenges to the traditional Enterprise Information Systems (EIS). More and more networked manufacturing entities are combined with data sensing, collection, transmission, and actuation capabilities. EIS are now facing large amounts of heterogeneous data. To address this issue, this paper proposes a notification-oriented solution for the data-intensive EIS within a distributed, collaborative, and heterogeneous environment. The solution is then applied in terms of model to a cloud-based smart factory prototype. This work indicates the suitability of the proposition and discusses the existing drawbacks and perspectives that include the manual modelling process and the application on a prototype.

An Insight in Perspective about the Capitalization of Knowledge in Software Engineering

The knowledge-intensive nature of software production and its growing demand suggest the need to define appropriate means to capitalize on the knowledge involved in software production and, thus, minimize the problems relating to time, cost and quality. The capitalization of knowledge can be approached under different views or perspectives. Thus, this article presents four perspectives on which the capitalization of knowledge in software engineering can be analyzed: Value, Safety, Utility and State. Each perspective guides a distinct view, but interrelated, over which the knowledge involved in software engineering can be observed and evaluated.