| 1. |
- Kenward, R. E., et al.
(författare)
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Identifying governance strategies that effectively support ecosystem services, resource sustainability, and biodiversity
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:13, s. 5308-5312
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Tidskriftsartikel (refereegranskat)abstract
- Conservation scientists, national governments, and international conservation groups seek to devise, and implement, governance strategies that mitigate human impact on the environment. However, few studies to date have systematically investigated the performance of different systems of governance in achieving successful conservation outcomes. Here, we use a newly-developed analytic framework to conduct analyses of a suite of case studies, linking different governance strategies to standardized scores for delivering ecosystem services, achieving sustainable use of natural resources, and conserving biodiversity, at both local and international levels. Our results: (i) confirm the benefits of adaptive management; and (ii) reveal strong associations for the role of leadership. Our work provides a critical step toward implementing empirically justified governance strategies that are capable of improving the management of human-altered environments, with benefits for both biodiversity and people.
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| 2. |
- Keskin, U., et al.
(författare)
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An engineering approach to synchronization based on overrun for compositional real-time systems
- 2011
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Ingår i: SIES 2011 - 6th IEEE International Symposium on Industrial Embedded Systems, Conference Proceedings. - 9781612848204 ; , s. 274-283
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Konferensbidrag (refereegranskat)abstract
- Hierarchical scheduling frameworks (HSFs) provide means for composing complex real-time systems from well-defined independently developed and analyzed subsystems. To support shared logical resources requiring mutual exclusive access in two-level HSFs, overrun without payback has been proposed as a mechanism to prevent budget depletion during resource access arbitrated by the stack resource policy (SRP). In this paper, we revisit the global schedulability analysis of synchronization protocols based on SRP and overrun without payback for fixed-priority scheduled HSFs. We derive a new global schedulability analysis based on the observation that the overrun budget is merely meant to prevent budget depletion during global resource access. The deadline of a subsystem therefore only needs to hold for its normal budget rather than the sum of the normal and overrun budget. Our novel analysis is considerably simpler than an earlier, initially improved analysis, which improved both the original local and global schedulability analyses. We evaluate the new analysis based on an extensive simulation study and compare the results with the existing analysis. Our simplified analysis does not significantly affect schedulability compared to the initially improved analysis. It is therefore proposed as a preferable engineering approach to synchronization protocols for compositional real-time systems. We accordingly present the implementation of our improvement in an OSEK-compliant real-time operating system to sketch its applicability in today's industrial automotive standards. Both implementation and run-time overheads are discussed providing measured results1. © 2011 IEEE.
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| 3. |
- Van Den Heuvel, M. M. H. P., et al.
(författare)
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Performance evaluation of analysis methods for arbitrating non-preemptive resource access in compositional real-time systems
- 2014
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Ingår i: 19th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2014. - 9781479948468 ; , s. Article number 7005065-
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Konferensbidrag (refereegranskat)abstract
- In this paper, we compare and survey different ways to model the scheduling delays corresponding to non-preemptive critical sections being executed by the tasks of different components that ultimately need to share one processor. We focus on the performance of compositional timing analyses for systems and we compare different protocols for the arbitration of tasks that wish to execute critical sections. Such analysis methods support timing predictable composition of independently validated components. This validation consists of analyzing the worst-case impact of critical sections on the schedules of the component's tasks. Finally, we evaluate the performance of the analysis methods by means of a simulation study.
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| 4. |
- Lönnqvist, Tomas, 1979-, et al.
(författare)
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Large-scale biogas generation in Bolivia – A stepwise reconfiguration
- 2018
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Ingår i: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 180, s. 494-504
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Tidskriftsartikel (refereegranskat)abstract
- Renewable energy is well recognized not only as resource that helps to protect the environment for future generations but also as a driver for development. Waste-to-energy systems can provide renewable energy and also improve sustainability in waste management. This article contributes a case study of stepwise reconfiguration of the waste management system in a developing country to the literature of transitions. The conditions for a systemic transition that integrates large-scale biogas generation into the waste management system have been analyzed. The method included a multi-criteria evaluation of three development steps for biogas, an economic analysis, and an institutional and organizational analysis. The results revealed economic as well as institutional and organizational barriers. Clearly, public and private sectors need to engage in sustainability. There is also a lack of pressure – mainly because of fossil fuel subsidies – that prevents a transition and creates a lock-in effect. To break the lock-in effect the municipality's institutional capacity should be strengthened. It is possible to strengthen biogas economically by integrated waste management services and sales of biofertilizer. A stepwise reconfiguration would be initiated by adopting technologies that are already established in many developed countries but are novelties in a Bolivian context – as a response to sustainability challenges related to waste management. The article focuses on the main challenges and the potential for biogas technology in Bolivia and a pathway towards a new, more sustainable system is suggested.
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| 5. |
- Overmeer, Thomas, et al.
(författare)
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Do physical therapists change their beliefs, attitudes,knowledge, skills and behaviour after a biopsychosocially orientated university course?
- 2009
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Ingår i: Journal of Evaluation In Clinical Practice. - Oxford : Blackwell. - 1356-1294 .- 1365-2753. ; 15:4, s. 724-732
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Tidskriftsartikel (refereegranskat)abstract
- Aim The aim of this study is to examine the effects of an 8-day university-based training course, aimed at identifying and addressing psychosocial prognostic factors during physiotherapy treatment, in shifting therapists towards a more biopsychosocial orientation as measured by changes in beliefs/attitudes, knowledge, skills and behaviour.MethodWe combined a randomized controlled trail with a pre-post design. Forty-two physiotherapists applied for a university-accredited training course designed to enhance knowledge and management of psychosocial factors in their practice with patients suffering from musculoskeletal pain. The course participants were randomized either to receiving the course or to a waiting list for training. Attitudes and beliefs towards, and knowledge of psychosocial factors, patient vignettes and a video of an imaginary patient were tested before and after training. The patients of the course participants were asked to fill out a questionnaire with background questions at treatment start. The patients also received a questionnaire about the physical therapists' behaviour and patient satisfaction 6 weeks after treatment start.ResultsThe results show that physical therapists' attitudes and believes became more biopsychosocially and less biomedically orientated, they were less convinced that pain justifies disability and limitation of activities, and their knowledge and skills on psychosocial risk factors increased after a university-accredited training course. Yet despite these changes their patients perceived their practice behaviour before and after the course as similar and were equally satisfied with their treatment and treatment result.ConclusionA course, which enhanced biopsychosocial attitudes and beliefs, as well as increased such knowledge and skills did not change the way patients perceived their physical therapists. A future question is whether it improves patient outcome.
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| 6. |
- Van Den Heuvel, M. M. H. P., et al.
(författare)
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Optimal and fast composition of resource-sharing components in hierarchical real-time systems
- 2014
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Ingår i: RTCSA 2014 - 20th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications. - 9781479939534 ; , s. Article number 6910547-
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Konferensbidrag (refereegranskat)abstract
- In this paper we consider various flavors of the stack resource policy (SRP) for arbitrating access to shared resources in a hierarchical scheduling framework (HSF) upon a uni-processor. We propose algorithms for exploring and selecting the (local) resource ceilings within components, such that it results in an optimal composition of resource-sharing components in an HSF. Existing methods are non-optimal, because (i) they optimize just the length of global non-preemptive execution of tasks and (ii) they do not detect whether or not resources are shared globally (i.e., between tasks of different components). Lifting these limitations leads to an exponential growth of the design space. This paper contributes a fast three-step methodology which lifts these limitations, i.e., we apply the SRP at each level of the HSF to just the resources being shared. Our algorithm selects those component interfaces (i.e., by fixing the local resource ceilings of each component) that minimize the system load.
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| 7. |
- Afshar, Sara, et al.
(författare)
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Flexible spin-lock model for resource sharing in multiprocessor real-time systems
- 2014
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Ingår i: Proc. IEEE Int. Symp. Ind. Embedded Syst., SIES. - 9781479940233 ; , s. 41-51
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Konferensbidrag (refereegranskat)abstract
- Various approaches can be utilized upon resource locking for mutually exclusive resource access in multiprocessor platforms. So far two conventional approaches exist for dealing with tasks that are blocked on a global resource in a multi-processor platform. Either the blocked task performs a busy wait, i.e. spins, at the highest priority level until the resource is released, or it is suspended. Although both approaches provide mutually exclusive access to resources, they can introduce long blocking delays to tasks, which may be unacceptable for many industrial applications. In this paper, we propose a general spin-based model for resource sharing in multiprocessor platforms in which the priority of the blocked tasks during spinning can be selected arbitrarily. Moreover, we provide the analysis for two selected spin-lock priorities and we show by means of a general comparison as well as specific examples that these solutions may provide a better performance for higher priority tasks.
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| 8. |
- Afshar, Sara, et al.
(författare)
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Intra-component Resource Sharing on a Virtual Multiprocessor Platform
- 2016
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Ingår i: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; , s. 31-32
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Konferensbidrag (refereegranskat)abstract
- Component-based software development facilitates the development process of large and complex software systems. By the advent of multiprocessors, the independently developed components can be integrated on a multi-core platform to achieve an efficient use of system hardware and a decrease in system power consumption and costs. In this paper, we consider a virtual multiprocessor platform where each component can be dynamically allocated to any set of processors of the platform with a maximum concurrency level. Global-EDF is used for intra-component scheduling. The existing analysis for such systems have assumed that tasks are independent. In this paper, we enable intra-component resource sharing for this platform. We investigate using a spin-based resource sharing protocol with the accompanying analysis that extends the existing analysis for independent tasks. We briefly illustrate and evaluate our initial results with an example.
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| 9. |
- Afshar, Sara
(författare)
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Lock-Based Resource Sharing for Real-Time Multiprocessors
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Embedded systems are widely used in the industry and are typically resource constrained, i.e., resources such as processors, I/O devices, shared buffers or shared memory might be limited in the system. Hence, techniques that can enable an efficient usage of processor bandwidths in such systems are of great importance. Locked-based resource sharing protocols are proposed as a solution to overcome resource limitation by allowing the available resources in the system to be safely shared. In recent years, due to a dramatic enhancement in the functionality of systems, a shift from single-core processors to multi-core processors has become inevitable from an industrial perspective to tackle the raised challenges due to increased system complexity. However, the resource sharing protocols are not fully mature for multi-core processors. The two classical multi-core processor resource sharing protocols, spin-based and suspension-based protocols, although providing mutually exclusive access to resources, can introduce long blocking delays to tasks, which may be unacceptable for many industrial applications. In this thesis we enhance the performance of resource sharing protocols for partitioned scheduling, which is the de-facto scheduling standard for industrial real-time multi-core processor systems such as in AUTOSAR, in terms of timing and memory requirements. A new scheduling approach uses a resource efficient hybrid approach combining both partitioned and global scheduling where the partitioned scheduling is used to schedule the major number of tasks in the system. In such a scheduling approach applications with critical task sets use partitioned scheduling to achieve higher level of predictability. Then the unused bandwidth on each core that is remained from partitioning is used to schedule less critical task sets using global scheduling to achieve higher system utilization. These scheduling schema however lacks a proper resource sharing protocol since the existing protocols designed for partitioned and global scheduling cannot be directly applied due to the complex hybrid structure of these scheduling frameworks. In this thesis we propose a resource sharing solution for such a complex structure. Further, we provide the blocking bounds incurred to tasks under the proposed protocols and enhance the schedulability analysis, which is an essential requirement for real-time systems, with the provided blocking bounds.
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| 10. |
- Afshar, Sara, et al.
(författare)
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Per Processor Spin-Lock Priority for Partitioned Multiprocessor Real-Time Systems
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Two traditional approaches exist for a task that is blocked on a global resource; a task either performs a non-preemptive busy wait, i.e., spins, or suspends and releases the processor. Previously, we have shown that both approaches can be viewed as spinning either at the highest priority HP or at the lowest priority on the processor LP, respectively. Based on this view, previously we have generalized a task's blocking behavioral model, as spinning at any arbitrary priority level. In this paper, we focus on a particular class of spin-lock protocols from the introduced flexible spin-lock model where spinning is performed at a priority equal to or higher than the highest local ceiling of the global resources accessed on a processor referred to as CP spin-lock approach. In this paper, we assume that all tasks of a specific processor are spinning on the same priority level. Given this class and assumption, we show that there exists a spin-lock protocol in this range that dominates the classic spin-lock protocol which tasks spin on highest priority level (HP). However we show that this new approach is incomparable with the CP spin-lock approach. Moreover, we show that there may exist an intermediate spin-lock approach between the priority used by CP spin-lock approach and the new introduced spin-lock approach that can make a task set schedulable when those two cannot. We provide an extensive evaluation results comparing the HP, CP and the new proposed approach.
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