To increase the success in computer programming courses, it is important to understand the learning process and common difficulties faced by students. Although several studies have investigated possible relationships between students performance and self-regulated learning characteristics in computer programming courses, little attention has been given to the source code produced by students in this regard. Such source code might contain valuable information about their learning process, specially in a context where practical programming assignments are frequent and students should write source code constantly during the course. This paper presents a strategy to support the correlation analysis among students performance, motivation, use of learning strategies, and source code metrics in computer programming courses. A comprehensive case study is presented to evaluate the proposed strategy through collected data (self-regulated learning characteristics and source code) from 205 undergrad students that accepted to participate voluntarily in the study during three semesters. Results show that the main features from source code which are significantly related to students performance and self-regulated learning features are: length-related metrics, with mainly positive correlations; and Halstead complexity measures, correlated negatively.

Integrity assurance of configuration data has a significant impact on microcontroller-based systems reliability. This is especially true when running applications driven by events which behavior is tightly coupled to this kind of data. This work proposes a new hybrid technique that combines hardware and software resources for detecting and recovering soft-errors in system configuration data. Our approach is based on the utilization of a common built-in microcontroller resource (timer) that works jointly with a software-based technique, which is responsible to periodically refresh the configuration data. The experiments demonstrate that non-destructive single event effects can be effectively mitigated with reduced overheads. Results show an important increase in fault coverage for SEUs and SETs, about one order of magnitude.

The protection of processor-based systems to mitigate the harmful effect of transient faults (soft errors) is gaining importance as technology shrinks. At the same time, for large segments of embedded markets, parameters like cost and performance continue to be as important as reliability. This paper presents a compiler-based methodology for facilitating the design of fault-tolerant embedded systems. The methodology is supported by an infrastructure that permits to easily combine hardware/software soft errors mitigation techniques in order to best satisfy both usual design constraints and dependability requirements. It is based on a generic microprocessor architecture that facilitates the implementation of software-based techniques, providing a uniform isolated-from-target hardening core that allows the automatic generation of protected source code (hardened code). Two case studies are presented. In the first one, several software-based mitigation techniques are implemented and evaluated showing the flexibility of the infrastructure. In the second one, a customized fault tolerant embedded system is designed by combining selective protection on both hardware and software. Several trade-offs among performance, code size, reliability, and hardware costs have been explored. Results show the applicability of the approach. Among the developed software-based mitigation techniques, a novel selective version of the well known SWIFT-R is presented.

Technological advances of Field Programmable Gate Array (FPGA) are making that this technology becomes the most preferred platform for the rapid prototyping of highly integrated digital systems. In addition, protection of processor-based systems to mitigate the harmful effects of radiation-induced upset events is gaining importance while technology shrinks. In this context, the main contribution of this work is a novel rapid prototyping approach for the co-design of dependable embedded systems using FPGA. This is supported by a hardening platform that allows combining software-only fault-tolerance techniques with hardware-only approaches, representing several trade-offs among design constraints, reliability and cost. As case study, several radiation-tolerant embedded systems have been developed based on a technology-independent version of the Picoblaze processor.

The protection of processor-based systems to mitigate the harmful effects of transient faults (hardening) is gaining importance as technology shrinks. Hybrid hardware/software hardening approaches are promising alternatives in the design of such fault tolerant systems. This paper presents a compiler-based infrastructure for facilitating the exploration of the design space between hardware-only and software-only fault tolerant techniques. The compiler design is based on a generic architecture that facilitates the implementation of software-based techniques, providing an uniform isolated-from-target hardening core. In this way, these methods can be implemented in an architecture independent way and can easily integrate new protection mechanisms to automatically produce hardened code. The infrastructure includes a simulator that provides information about memory and execution time overheads to aid the designer in the co-design decisions. The tool-chain is complemented by a hardware fault emulation tool that allows to measure the fault coverage of the different solutions running on the real system. A case study was implemented allowing to evaluate the flexibility of the infrastructure to fit the reliability requirements of the system within their memory and performance restrictions.