Sérgio F. Lopes

Design and Description of a Classification System Framework for Easier Reuse

Frameworks are an important technology to reduce software development costs and shorten the time-to-market. However, framework complexity presents reuse problems that limit its success as an application development alternative. It has been widely recognized that is necessary to effectively communicate frameworks and provide appropriate tool support, but we argue that difficulties are also related to the considered framework model. We find that the level of support that tools can provide is decisively dependent on the kind of available framework documentation, which in turn is intimately tied to the considered framework model. In this paper, we present our framework model and respective supporting notation. We describe their appliance to the design and description of an application framework. This case study illustrates how the proposed model and documentation approach alleviate difficulties of framework reuse, namely its comprehension and instantiation

Application Development by Reusing Object-Oriented Frameworks

Object-oriented frameworks are an important form of reuse that can help to decrease significantly the application development time and cost. Although widely known, there are still some difficulties associated with them that are critical to its success. These problems have to be alleviated to make the framework reuse an attractive alternative to application development. We focus on the issues regarding the framework reuse process, more specifically, framework architecture description, its adaptation with application specific components, and final application instantiation. This paper discusses our position on these subjects and, based on previous work, we propose a different approach and appropriate tool support

Development of a library for clients of ONVIF video cameras: Challenges and solutions

The interoperability of IP video equipment is a critical problem for surveillance systems and other video application developers. ONVIF is one of the two specifications addressing the standardization of networked devices interface, and it is based on SOAP. This paper addresses the development of an ONVIF library to develop clients of video cameras. We address the choice of a web services toolkit, and how to use the selected toolkit to develop a basic library. From that, we discuss the implementation of features that are important challenges for developers and, therefore, opportunities for providing higher-level functionalities. The proposed solutions result from the implementation of library that has been validated in industry.

Framework Characteristics - A Starting Point for Addressing Reuse Difficulties

Frameworks are a fundamental reuse technique, but they are often hard to learn and reuse. Documentation approaches and tools supporting instantiation have been the main research subjects for addressing framework reuse difficulties. This paper introduces a new approach that starts from a more fundamental level – framework characteristics. These are shaped by programming and design techniques, and their impact on reuse difficulties is analysed. From there, a framework model making a congruent combination of characteristics is defined. The results are demonstrated with a case study framework. Both the problem analysis and the proposed solution are relevant for the conference topics, namely framework reuse and design methods.

Library for Simplified Timer Implementation using Standard C

Temporization is a crucial aspects of control, automation and robotics systems. C++ is used in the development of such systems, especially if they are more complex and powerful. Because, the language and standard library do not support non-blocking timers with callbacks for event-driven programming, developers resort to libraries and frameworks that offer such functionality. However, their timer implementations are dependent on platform specificities and thus have more limited portability. C++11 has introduced features that enable standard implementations of timers. We propose a library that implements timers with simplified usage relatively to well-known libraries. The proposed library is contrasted with timers of two well know libraries, through a series of usage scenarios. We describe the design and provide performance measurements. The results show that it is faster and offers more accurate temporization.

Exploiting Template Metaprogramming to customize an object-oriented operating system

Nowadays, the growing complexity of embedded systems demands for configurability, variability and reuse. Conditional compilation and object-orientation are two of the most applied approaches in the management of system variability. While the former increases the code management complexity, the latter leverages the needed modularity and adaptability to simplify the development of reusable and customizable software at the expense of performance and memory penalty. This paper shows how C++ TMP (Template Metaprogramming) can be applied to manage the variability of an object-oriented operating system and at the same time get ride out of the performance and memory footprint overhead. In doing so, it will be statically generated only the desired functionalities, thus ensuring that code is optimized and adjusted to application requirements and hardware resources.

LP805X: A customizable and low power 8051 soft core for FPGA applications

In todays advanced technological age, embedded and real time systems have become ubiquitous, covering a wide range of applicability. As a result there is an ever growing need for low power capabilities along with reasonable performance, thus presenting a virtual demand for power-aware devices. The purpose of this work was leveraging key techniques and technologies such as design laziness, componentware design, generative design, separation of mechanism and policy, voltage-frequency island, state encoding, clock gating, and operand isolation, and then investigating their effects while designing an energy and power-conscious microcontroller based on 8051 ISA (Instruction Set Architecture) without disregard to silicon area, required application functionalities and performance. Simulations show that our purposed 2 stage pipeline system with built-in hybrid scheduler operates at 230μW@1MHz.

An easy-to-use and flexible object-oriented framework for extended finite state machines

Finite state machines (FSMs) are widely used as a mean to model the behavior of systems and/or processes, but they are not supported by general purpose programming languages. To avoid implementations that are difficult to develop, and mostly maintain, frameworks have been developed for the FSM domain. Ideally, frameworks should be easy to learn and use, and provide as much support as possible. They should also enforce design rules, while keeping flexibility. However, there are tradeoffs between these aspects, and thus a balance must be found. Object-oriented frameworks that we have found in the literature do not meet this set of characteristics, but one stands out. We discuss its use to develop an example application (electric lock control), demonstrating important limitations. Based on that analysis, we propose a new framework that is small, efficient, and provides a powerful set of features for implementing FSMs. The framework is easy to learn and use, fully supports both Mealy and Moore machines, enables semantically correct state minimization, and offers conditional transitions.

An architectural model for small-scale component-oriented frameworks

Frameworks are an important form of reuse. However, they are often complex and hard to understand, what limits their success as a reuse option. To answer this problem, it has been widely recognized the need to effectively communicate frameworks and provide appropriate tool support, but difficulties still endure. We argue that the properties of frameworks are another aspect that is decisive for reuse problems and has not been sufficiently explored. We discuss these issues and we propose a framework architectural model that can be used to design frameworks that are easier to reuse.

Development of Embedded Systems Using Oort

The development of embedded systems requires both tools and methods which help the designer to deal with the higher complexity and tougher constraints due to the different hardware support, often distributed topology and time requirements. Proper tools and methods have a major impact on the overall costs and final product quality. We have applied the Object-Oriented Real-Time Techniques (OORT) method, which is oriented toward the specification of distributed realtime systems, to the implementation of the Multiple Lift System (MLS) case study. The method is based on the UML, SDL and MSC languages and supported by the ObjectGEODE toolset. This paper summarizes the method and presents our experience in the MLS system development, namely the difficulties we had and the success we have achieved.