This book constitutes the thoroughly refereed post-conference proceedings of the 26th International Workshop on Algebraic Development Techniques, WADT 2022, held in Aveiro, Portugal, in June 2022. The 6 revised papers presented together with 2 invited papers were carefully reviewed and selected from 25 submissions. The contributed presentations covered a range of topics about the algebraic approach to system specification, which encompasses many aspects of the formal design of software systems. Originally born as formal method for reasoning about abstract data types, the algebraic approach now covers new specification frameworks and programming paradigms (such as object-oriented, aspect-oriented, agent-oriented, logic, and higher-order functional programming) as well as a wide range of application areas (including information systems, concurrent, distributed, and mobile systems).

Flexible manufacturing systems (FMS) are essential for small/medium batch and job shop manufacturing. These types of production systems are used to manufacture a considerable variety of products with medium/small production volumes. Therefore, the manufacturing platforms supporting these types of production must be flexible and organized in flexible manufacturing cells (FMC). Programming FMCs remains a difficult task and is an actual area of research and development. This paper reports an object-oriented approach developed for FMC programming. The work presented was first thought for application in industrial robot manipulators, and later extended to other FMC equipments just by putting the underlying ideas in a general framework. Initially, the motivation for this work was to develop means to add force control to a standard industrial robot manipulator. This problem requires remote access to the robot controller, remote programming and monitoring, as also is required to program and monitor any other FMC equipment. The proposed approach is distributed based on a client/server model and runs on Win32 platforms, i.e., Microsoft Windows and Windows NT. Implementation for the special case of industrial robot manipulators is presented, along with some application examples used for educational, research and industrial purposes.

Object-oriented programming (OOP) is the most successful paradigm used in programming environments. Some difficulties arise when it is necessary to deal with data stored in a relational database because relational databases do not provide an object-oriented interface to their entities. The most common solution consists in developing a specific interface that guarantees some specific requirements. Here, we explain a methodology to implement an application-side object-oriented platform in order to access stored procedures in relational databases.

Although mainstream object-oriented languages, like Java, are currently able to detect and prevent many programming errors by static type-checking, common usage-related errors are not captured and signaled to programmers. In general, no (formal) support is available in these languages for ensuring that an object is used according to the protocol which the programmer had in mind when describing the behavior of a class. The file reader protocol is a simple but clarifying example: first a file must be opened, then it can be read multiple times (though not beyond the end-of-file), and finally it must be closed. As client code is not checked for protocol conformance, trying to read the file without first opening it, or when it is closed, are simple disregards caught only by runtime exceptions, assuming the language is equipped with built-in support to handle errors and exceptional events. The MOOL programming language presented in this work is an attempt to formalize object usage and access. It consists in a simple class-based object-oriented language that includes standard primitives found in most object-oriented language formalisms. Additionally, the language offers constructs that can be attached at class definitions for specifying (1) the available methods based on an object state, and (2) how methods may be called in that state – by a single client, in which case we say that the object has a linear status, or without restrictions, in which case we say it has a shared one. We refer to this abstract view that defines an object state and status the class usage type. We formalize the language syntax, the operational semantics, and a type system that enforces by static typing that methods are called only when available, and by a single client if so specified in the class usage type. We illustrate the language capabilities by encoding in MOOL the protocols of two well-known examples: the file reader and the auction system. We have built a prototype compiler to implement our ideas, and its architecture is also described. Finally, we anticipate some of the related topics which we are interested in pursuing in future work.

The phenomena studied in Fracture Mechanics can be observed either in Nature, the most sophisticated systems or ordinary structures. As a consequence, Engineers need to be alert for investigating the variety of complex mechanisms, related with fracture processes, which are capable of appearing in these systems. The possibility of failure is a real premise has to be considered not only in the design of structures, but also throughout their life. Undoubtedly, in this context Fracture Mechanics should be used to carry out prognostics of potential crack propagation patterns, verifying if there exists or not risk of keeping a structure in service usage. An alternative formulation widely applied to simulate fracture behavior is the Cohesive Zone Modeling (CZM) approach. It is a scientific branch of Fracture Mechanics originally proposed by Barenblatt (1959, 1962) and Dugdale (1960), and which after Xu and Needleman s works (1993, 1994) has acquired a great acceptance in scientific community. For this reason, the present work employs Xu and Needleman s model to simulate dynamic crack propagation in brittle materials, introducing the Software for Simulation of Dynamic Cohesive Fracture (DyCOH), which is based on Object-Oriented Programming (OOP) paradigm for facilitating future reuse and extension of implemented code. Using DyCOH software two numerical applications are shown. First, for verification purpose, the classical Xu and Needleman s problem is simulated and the response of DyCOH is compared with literature results. Second, for didactic aspiration, a simpler problem is studied in order to understand the influence of loading speed on fracture patterns of a tie-bar.

ABSTRACT: The aim of this study is to model launch vehicles with focus on 3-DOF trajectory optimization using a modular approach. Despite the large number of operational launch vehicles, they usually consist of basic components and subsystems. In other words, a launch vehicle is an assembly of stages, which in turn is divided into propellant system and engine, and the engine is an assembly of basic components such as pumps, turbines, combustion chamber, and nozzle. To allow future extension and reuse of the codes, a modular structure using object-oriented programming is used. Two formulations of state equations of the trajectory and two optimization methods are described. The launch vehicle performance will be measured by payload mass for a given mission. The simulations of the VLS-1, Ariane 5 and VLS-Alfa were performed and showed good agreement with the literature.

Abstract This paper shows and discusses a generic implementation of the global-local analysis toward generalized finite element method (GFEMgl). This implementation, performed into an academic computational platform, follows the object-oriented approach presented by the authors in a previous work for the standard version of GFEM in which the shape functions of finite elements are hierarchically enriched by analytical functions, according to the problem behavior. In global-local GFEM, however, the enrichment functions are constructed numerically from the solution of a local problem. This strategy allows the use of a coarse mesh even when the problem produces complex stress distributions. On the other hand, a local problem is defined where the stress field presents high gradients and it is discretized using a large number of elements. The results of the local problem are used to enrich the global problem which improves the approximate solution. The great advantage is allowing a well-refined description of the local problem, when necessary, avoiding an overburden for the computation of the global solution. Details of the implementation are presented and important aspects of using this strategy are highlighted in the numerical examples.