2015
Authors
Maia, C; Yomsi, PM; Nogueira, L; Pinho, LM;
Publication
PROCEEDINGS IEEE/IFIP 13TH INTERNATIONAL CONFERENCE ON EMBEDDED AND UBIQUITOUS COMPUTING 2015
Abstract
This paper explores the behavior of parallel forkjoin tasks on multicore platforms by resorting to a semi-partitioned scheduling model. This model offers a promising framework to embedded systems which are subject to stringent timing constraints as it provides these systems with very interesting properties. The proposed approach consists of two stages-an offline stage and an online stage. During the offline stage, a multi-frame task model is adopted to perform the forkjoin task-to-core mapping so as to improve the schedulability and the performance of the system, and during the online stage, work-stealing is exploited among cores to improve the system responsiveness as well as to balance the execution workload. The objective of this work is twofold: (1) to provide an alternative technique that takes advantage of the semi-partitioned scheduling properties by offering the possibility to accommodate forkjoin tasks that cannot be scheduled in any pure partitioned environment, and (2) to reduce the migration overhead which has shown to be a traditional major source of non-determinism in global approaches. The simulation results show an improvement of the proposed approach over the state-of-the-art of up to 15% of the average response-time per task set.
2015
Authors
Gonçalves, JF; De Mendes, JJM; Resende, MGC;
Publication
Handbook on Project Management and Scheduling Vol. 2
Abstract
In this chapter the Basic Multi-Project Scheduling Problem (BMPSP) is described, an overview of the literature on multi-project scheduling is provided, and a solution approach based on a biased random-key genetic algorithm (BRKGA) is presented. The BMPSP consists in finding a schedule for all the activities belonging to all the projects taking into account the precedence constraints and the availability of resources, while minimizing some measure of performance. The representation of the problem is based on random keys. The BRKGA generates priorities, delay times, and release dates, which are used by a heuristic decoder procedure to construct parameterized active schedules. The performance of the proposed approach is validated on a set of randomly generated problems. © Springer International Publishing Switzerland 2015.
2015
Authors
Teixeira, D; Cruz, A; Bráz, S; Moreira, A; Relvas, J; Camacho, R;
Publication
Proceedings of the 30th Annual ACM Symposium on Applied Computing
Abstract
2015
Authors
Curzon, P; Thimbleby, H; Masci, P;
Publication
Proceedings of the 5th EAI International Conference on Wireless Mobile Communication and Healthcare - "Transforming healthcare through innovations in mobile and wireless technologies"
Abstract
2015
Authors
Pereira C.; Varajão J.; Amaral L.; Soares D.S.; Cunha A.;
Publication
Atas da Conferencia da Associacao Portuguesa de Sistemas de Informacao
Abstract
Over the last decades the role of information systems (IS) has evolved and has become truly important within organizations. Despite this evidence, not all organizations have the internal resources and know-how required to develop it. The outsourcing of IS services have been presented as an alternative and strategic option in the management of this function in many organizations and various sectors of activity. Developing a better understanding of the main IS services outsourcing practices in the banking sector, given their particularities (eg with regard to confidentiality requirements and secrecy), is the central objective of this work. To this end, a survey was conducted based on a questionnaire in order to characterize, among other things, the services subject to outsourcing, the main motivations, risks, barriers and impacts associated with the outsourcing as well as contracting aspects, customer-supplier relationship and satisfaction. The main results are presented in this paper.
2015
Authors
Machado, N; Lucia, B; Rodrigues, L;
Publication
ACM SIGPLAN NOTICES
Abstract
We present Symbiosis: a concurrency debugging technique based on novel differential schedule projections (DSPs). A DSP shows the small set of memory operations and data-flows responsible for a failure, as well as a reordering of those elements that avoids the failure. To build a DSP, Symbiosis first generates a full, failing, multithreaded schedule via thread path profiling and symbolic constraint solving. Symbiosis selectively reorders events in the failing schedule to produce a non-failing, alternate schedule. A DSP reports the ordering and data-flow differences between the failing and non-failing schedules. Our evaluation on buggy real-world software and benchmarks shows that, in practical time, Symbiosis generates DSPs that both isolate the small fraction of event orders and data-flows responsible for the failure, and show which event reorderings prevent failing. In our experiments, DSPs contain 81% fewer events and 96% fewer data-flows than the full failure-inducing schedules. Moreover, by allowing developers to focus on only a few events, DSPs reduce the amount of time required to find a valid fix.
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