Approaches to High-Level Programming and Prototyping of Concurrent Applications

Concurrent programming is conceptually harder to undertake and to understand than sequential programming, because a programmer has to manage the coexistence and coordination of multiple concurrent activities. To alleviate this task several high-level approaches to concurrent programming have been developed. For some high-level programming approaches, prototyping for facilitating early evaluation of new ideas is a central goal. Prototyping is used to explore the essential features of a proposed system through practical experimentation before its actual implementation to make the correct design choices early in the process of software development. Approaches to prototyping concurrent applications with very high-level programming systems intend to alleviate the development of parallel algorithms in quite different ways. Early experimentation with alternate design choices or problem decompositions for concurrent applications is suggested to make concurrent programming easier. This paper presents a survey of approaches to high-level programming and prototyping of concurrent applications to review the state of the art in this area. The surveyed approaches are classified with respect to the prototyping process

GRAPHICAL CONFIGURATION PROGRAMMING - THE STRUCTURAL DESCRIPTION, CONSTRUCTION AND EVOLUTION OF SOFTWARE SYSTEMS USING GRAPHICS

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Teaching programming with computational and informational thinking

Computers are the dominant technology of the early 21st century: pretty well all aspects of economic, social and personal life are now unthinkable without them. In turn, computer hardware is controlled by software, that is, codes written in programming languages. Programming, the construction of software, is thus a fundamental activity, in which millions of people are engaged worldwide, and the teaching of programming is long established in international secondary and higher education. Yet, going on 70 years after the first computers were built, there is no well-established pedagogy for teaching programming. There has certainly been no shortage of approaches. However, these have often been driven by fashion, an enthusiastic amateurism or a wish to follow best industrial practice, which, while appropriate for mature professionals, is poorly suited to novice programmers. Much of the difficulty lies in the very close relationship between problem solving and programming. Once a problem is well characterised it is relatively straightforward to realise a solution in software. However, teaching problem solving is, if anything, less well understood than teaching programming. Problem solving seems to be a creative, holistic, dialectical, multi-dimensional, iterative process. While there are well established techniques for analysing problems, arbitrary problems cannot be solved by rote, by mechanically applying techniques in some prescribed linear order. Furthermore, historically, approaches to teaching programming have failed to account for this complexity in problem solving, focusing strongly on programming itself and, if at all, only partially and superficially exploring problem solving. Recently, an integrated approach to problem solving and programming called Computational Thinking (CT) (Wing, 2006) has gained considerable currency. CT has the enormous advantage over prior approaches of strongly emphasising problem solving and of making explicit core techniques. Nonetheless, there is still a tendency to view CT as prescriptive rather than creative, engendering scholastic arguments about the nature and status of CT techniques. Programming at heart is concerned with processing information but many accounts of CT emphasise processing over information rather than seeing then as intimately related. In this paper, while acknowledging and building on the strengths of CT, I argue that understanding the form and structure of information should be primary in any pedagogy of programming

An Object-oriented drawing package in smalltalk/v

Graphics creation applications tend to fall into two categories: bit-mapped paint packages, and object-oriented drawing packages. Although each interface has its own unique advantages, few vendors have attempted to integrate the two into a single package. Those who have tried have, in fact, poor integration both from the user\u27s perspective and in the underlying mathematical model. In this thesis, I have addressed the issue of integrating bit-mapped and object-oriented interfaces by creating an object-oriented graphics package which provides the user with a consistent interface for creating and manipulating both graphical objects and bit-mapped graphics. The consistency of the interface was facilitated by the consistency of the design, the underlying geometric model, and the implementation, all of which are themselves object-oriented. The thesis is written in Smalltalk/V for the Macintosh* . While the solution for this integration was not derived overnight, the use of object-oriented design principles sped the development of a complex graphical user interface, while providing fresh insight into the problem of representing bit-mapped objects. Because Smalltalk enforces the notion that every element in the system is an object, the Smalltalk developer is forced to begin designing his solution purely in terms of objects. This mind-set allowed me to view the point as no other graphics package has presented it: as a unique graphical entity (just as ll IS 1R formal geometry) available to the user as a graphical tool. As a result, users of my package are able to enjoy the benefits of both bit-mapped and object-oriented editors without ever abandoning an environment in which every graphical element is an object, in terms of both the interface and the underlying mathematical model

The 14th Overture Workshop: Towards Analytical Tool Chains

This report contains the proceedings from the 14th Overture workshop organized in connection with the Formal Methods 2016 symposium. This includes nine papers describing different technological progress in relation to the Overture/VDM tool support and its connection with other tools such as Crescendo, Symphony, INTO-CPS, TASTE and ViennaTalk

A Graphical Environment Supporting the Algebraic Specification of Abstract Data Types

Abstract Data Types (ADTs) are a powerful conceptual and practical device for building high-quality software because of the way they can describe objects whilst hiding the details of how they are represented within a computer. In order to implement ADTs correctly, it is first necessary to precisely describe their properties and behaviour, typically within a mathematical framework such as algebraic specification. These techniques are no longer merely research topics but are now tools used by software practitioners. Unfortunately, the high level of mathematical sophistication required to exploit these methods has made them unattractive to a large portion of their intended audience. This thesis investigates the use of computer graphics as a way of making the formal specification of ADTs more palatable. Computer graphics technology has recently been explored as a way of making computer programs more understandable by revealing aspects of their structure and run-time behaviour that are usually hidden in textual representations. These graphical techniques can also be used to create and edit programs. Although such visualisation techniques have been incorporated into tools supporting several phases of software development, a survey presented in this thesis of existing systems reveals that their application to supporting the formal specification of ADTs has so far been ignored. This thesis describes the development of a prototype tool (called VISAGE) for visualising and visually programming formally-specified ADTs. VISAGE uses a synchronised combination of textual and graphical views to illustrate the various facets of an ADT's structure and behaviour. The graphical views use both static and dynamic representations developed specifically for this domain. VISAGE's visual programming facility has powerful mechanisms for creating and manipulating entire structures (as well as their components) that make it at least comparable with textual methods. In recognition of the importance of examples as a way of illustrating abstract concepts, VISAGE provides a dedicated tool (called the PLAYPEN) that allows the creation of example data by the user. These data can then be transformed by the operations belonging to the ADT with the result shown by means of a dynamic, graphical display. An evaluation of VISAGE was conducted in order to detect any improvement in subjects' performance, confidence and understanding of ADT specifications. The subjects were asked to perform a set of simple specification tasks with some using VISAGE and the others using manual techniques to act as a control. An analysis of the results shows a distinct positive reaction from the VISAGE group that was completely absent in the control group thereby supporting the thesis that the algebraic specification of ADTs can be made more accessible and palatable though the use of computer graphic techniques

Squeak by Example

Squeak by Example, intended for both students and developers, will guide you gently through the Squeak language and environment by means of a series of examples and exercises. This book is made available under the Creative Commons Attribution-ShareAlike 3.0 license

Visual animation of LOTOS using SOLVE (extended version)

SOLVE (Specification using an Object-based, LOTOS-defined, Visual language) is designed to allow formal requirements capture, particularly for interactive systems. The SOLVE language is object-based, and formally defined using LOTOS (Language Of Temporal Ordering Specification). SOLVE is also a set of software tools that allow direct visual animation of systems specified in this language. Communicating objects control onscreen icons that can be manipulated directly by the user. Animation is supported by translating a SOLVE specification automatically into a LOTOS specification, and then simulating this using standard LOTOS tools. A VCR (Video Cassette Recorder) clock controller is used to illustrate the SOLVE approach. A further application is embodied in the XDILL tool that supports requirements specification and animation of digital logic circuits. The architecture of the SOLVE toolset is described

A Domain Specific Graphical User Interface Framework

Since the early days of software development, there has been an ongoing trend towards higher-order or higher level abstractions in programming languages, software libraries and application frameworks. Some of the arguments for software development tools with higher levels of abstraction include simpler software development, improved portability and better maintainability. Higher level abstractions can however lead to reduced performance. This thesis presents an innovative graphical user interface software solution that mixes high-level and low-level approaches to achieve acceptable performance while retaining good maintainability. The solution is an extension to a graphical application framework called JavaFX. The scope of this thesis is defined by a software development project which goal is to create a graphical user interface framework. The framework is used in the creation of customer specific user interfaces for an accompanying intralogistics system. The resulting user interfaces must be able to visualize possibly thousands of objects moving on a factory floor. The views must simultaneously support user-initiated zooming, panning, and tilting of the two-dimensional view. Meeting these requirements while maintaining acceptable performance, requires an unconventional solution and a deviation from idiomatic JavaFX. The user interface framework in question is developed using a high-level graphical user interface application framework called JavaFX. JavaFX is the most recent graphical user interface toolkit included in the official Java Development Kit. It has many reactive traits and other modern high-level properties. Overcoming performance challenges with JavaFX when producing views with thousands of animated items was the key research challenge in this research. Some attention is also given to replacing JavaFX built-in dependency injection system with Spring framework to improve JavaFX suitability to the task at hand. This thesis presents a hybrid solution that overcomes JavaFX’s performance challenges in the problem domain, while retaining as much as possible of the usefulness of the high-level features present in the JavaFX framework. The key innovation is a mechanism that enables automated rendering of sprite-bitmaps from JavaFX scene-graph nodes. The solution includes a system that draws the automatically generated bitmaps to a lower-level JavaFX component called Canvas. The solution enables layered mixing of regular JavaFX views with the custom high-performance views, including seamless resizing and event handling between the two types of views. The solution enables the developers of customer specific user interfaces to choose an appropriate graphics rendering type, such that only objects that cause performance issues, typically items which number exceeds dozens, need to use the more complex high-performance system