Value Types in Eiffel

Identifies a number of problems with Eiffel's expanded types in modelling value types, and proposes a backward compatible syntactic extension, and a modified semantics. The latter is also shown to be (effectively) backward compatible, in the sense that existing programs would run unaffected if compilers implemented the new semantics. The benefits of the approach are discussed, including an elegant approach to rebuilding data structure libraries

A Project Component in a Web Engineering Course

Web applications are an extremely important and ubiquitous part of today\u27s world. Students must not only know how to develop them from a technical perspective, but in doing so need to understand how to follow the proper principles of software engineering - delivering the project on time, on budget, and in a high quality manner. At the Department of Software Engineering at the Rochester Institute of Technology, we offer a Web Engineering course which not only introduces students to a variety of web technologies, but more importantly it shows them how to use them in a collaborative environment while properly utilizing web engineering methodologies.The course includes a significant project component requiring students to use a variety of contemporary technologies and resources to create a robust web application. The main premise of the project is for each group to create a web portal using both custom-built and already existing components. The project takes place over the entire 15 week course term, includes multiple releases, and has students work in teams of 4-5. This innovative project component has received significant praise from both students and faculty members while fulfilling an emerging area of our curriculum. Students enjoy the real-world nature of the project and the ability to work with contemporary technologies in a format which closely mimics what they will see in industry. This paper outlines the educational objectives, project details, some sample project results of our class offering, as well as student feedback about the project. The goal of this work is to share the project, its importance, and lessons learned for use at other institutions with similar educational goals

SSVEP-based Brain-Computer Interface Controlled Robotic Platform with Velocity Modulation

Steady-state visual evoked potential (SSVEP)-based brain-computer interfaces (BCIs) have been extensively studied due to many benefits, such as non-invasiveness, high information transfer rate, and ease of use. SSVEP-based BCI has been investigated in various applications by projecting brain signals to robot control commands. However, the movement direction and speed are generally fixed and prescribed, neglecting the user’s requirement for velocity changes during practical implementations. In this study, we proposed a velocity modulation method based on stimulus brightness for controlling the robotic arm in the SSVEP-based BCI system. A stimulation interface was designed, incorporating flickers, target and a cursor workspace. The synchronization of the cursor and robotic arm does not require the subject’s eye switch between the stimuli and the robot. The feature vector consists of the characteristics of the signal and the classification result. Subsequently, the Gaussian mixture model (GMM) and Bayesian inference were used to calculate the posterior probabilities that the signal came from a high or low brightness flicker. A brain-actuated speed function was designed by incorporating the posterior probability difference. Finally, the historical velocity was considered to determine the final velocity. To demonstrate the effectiveness of the proposed method, online experiments, including single- and multi-target reaching tasks, were conducted. The extensive experimental results validated the feasibility of the proposed method in reducing reaching time and achieving proximity to the target

Integrating measurement techniques in an Object-Orientedsystems design process.

The theme of this thesis is the assessment of quality in class hierarchies. In particular, the notion ofinheritance and the mechanism of redefinition from a modelling perspective are reviewed. It isshown that, in Object-Oriented languages, controversial uses of inheritance can be implementedand are subject of debate as they contradict the essence of inheritance. The discovery of anunexpected use of the method redefinition mechanism confirmed that potential designinconsistencies occur more often than expected in class hierarchies. To address such problems,design heuristics and measurement techniques are investigated as the main instrument tools for theevaluation "goodness" or "badness" in class hierarchies. Their benefits are demonstrated withinthe design process. After the identification of an obscure use of the method redefinition mechanism referred to as themultiple descendant redefinition (MDR) problem, a set of metrics based on the GQMlMEDEA[Bri&aI94] model is proposed. To enable a measurement programme to take place within a designprocess, the necessary design considerations are detailed and the technical issues involved in themeasurement process are presented. Both aspects form ~. methodological approach for classhierarchy assessment and especially concentrate on the use of the redefinition mechanism.. .As one of the main criticisms of the measure~ent science is the lack orgood design feedback, the, analysis and interpretation phase. of the metfics results is seen: as a crucial phase for inferring,meaningful conclusions. A novel· data interpretation framework is pr~posed' and includes the use ofvarious graphical data representations and detection techniques. Also, the notion of redefinitionprofiles suggested a, more generic approach whereby a pattern profile can be found for a metric.The benefits of the data interpretation method for the extraction of meaningful design feedbackfrom the metrics results are discussed.The implementation of a metric tool collector enabled a set of experiments to be carried out on theSmalltalk class hierarchy. Surprisingly, the analysis of metrics results showed that methodredefmition is heavily used compared to method extension. This suggested the existence ofpotential design inconsistencies in the class hierarchy and permitted the discovery of the MDRproblem on many occasions. In addition, a set of experiments demonstrates the benefits of examplegraphical representations together with detection techniques such as alarmers. In the light offacilitating the interpretation phase, the need for additional supporting tools is highlighted. This thesis illustrates the potential benefits of integration of measurement techniques within anObject-Oriented design process. Given the identification of the MDR problem, it is believed thatthe redefinition metrics are strong and simple candidates for detecting complex design problemsoccurring within a class hierarchy. An integrated design assessment model is proposed whichlogically fits into an incremental design development process. Benefits and disadvantages of theapproach are discussed together with future work