Abstract

Abstract
The IEC 61508 standard recognizes the programming languages defined in IEC 61131-3 as being appropriate for safety-related applications, and suggests the use of static analysis techniques to find errors in the source code. In this context, we have added a semantic verification stage to the MatIEC compiler—an open source ST, IL, and SFC code translator to ANSI C. In so doing, we have identified several issues related to the definition of the semantics of the IL and ST programming languages, as well as with the data type model defined in IEC 61131-3. Most of the issues are related to undefined semantics, which may result in applications generating distinct results, depending on the platform on which they are executed. In this paper we describe some of the issues we uncovered, explain the options we took, and suggest how the IEC 61131-3 standard could be made more explicit. © Springer International Publishing Switzerland 2013.

Abstract
The ability to map instructions running in a microprocessor to a reconfigurable processing unit (RPU), acting as a coprocessor, enables the runtime acceleration of applications and ensures code and possibly performance portability. In this work, we focus on the mapping of loop-based instruction traces (called Megablocks) to RPUs. The proposed approach considers offline partitioning and mapping stages without ignoring their future runtime applicability. We present a toolchain that automatically extracts specific trace-based loops, called Megablocks, from MicroBlaze instruction traces and generates an RPU for executing those loops. Our hardware infrastructure is able to move loop execution from the microprocessor to the RPU transparently, at runtime, and without changing the executable binaries. The toolchain and the system are fully operational. Three FPGA implementations of the system, differing in the hardware interfaces used, were tested and evaluated with a set of 15 application kernels. Speedups ranging from 1.26 × to 3.69 × were achieved for the best alternative using a MicroBlaze processor with local memory. © 2013 João Bispo et al.

Abstract

Abstract
In this paper an Artificial Bee Colony Approach for Scheduling Optimization is presented. The adequacy of the proposed approach is validated on the minimization of the total weighted tardiness for a set of jobs to be processed on a single machine and on a set of instances for Job-Shop scheduling problem. The obtained computational results allowed concluding about their efficiency and effectiveness. The ABC performance and respective statistical significance was evaluated.

Abstract
The multi-agent systems technology is a proper approach to implement distributed manufacturing systems exhibiting adaptation and flexibility. This paper proposes a multi-agent based solution for the adaptation of the functional test plan in a production line producing washing machines, aiming to increase the process productivity and product quality. The global adaptation mechanism is embedded on the multi-agent system infrastructure, allowing the optimized selection of tests based on the correlation of the quality data gathered along the production line. The proposed approach was developed and installed on a real production line producing washing machines under the European Seventh Framework Programme GRACE project.