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| 2. |
- Lindgren, Per, et al.
(författare)
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Robust real-time applications in Timber
- 2006
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Ingår i: 2006 IEEE International Conference on Electro/information Technology. - Piscataway, NJ : IEEE Communications Society. - 0780395921 ; , s. 191-196
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Konferensbidrag (refereegranskat)abstract
- Embedded systems are often operating under hard real-time constraints, for example in automotive applications. For such systems, robustness and reliability are crucial, which calls for rigorous system design and methodologies for validation. In this paper we advocate a design methodology for robust, realtime systems, based on Timber; a pure reactive system model that allows for formal reasoning about various system properties. We outline how system specifications in Timber can be "compiled" into efficient standalone executables for general light-weight microcontroller platforms. Methods for resource analysis and implications to system dimensioning and validation are further discussed.
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| 3. |
- Lindgren, Per, et al.
(författare)
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TinyTimber, reactive objects in C for real-time embedded systems
- 2008
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Ingår i: Proceedings, Design, Automation and Test in Europe. - New York : ACM Digital Library. - 9783981080131 ; , s. 1382-1385
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Konferensbidrag (refereegranskat)abstract
- Embedded systems are often operating under hard real-time constraints. Such systems are naturally described as time-bound reactions to external events, a point of view made manifest in the high-level programming and systems modeling language Timber. In this paper we demonstrate how the Timber semantics for parallel reactive objects translates to embedded real-time programming in C. This is accomplished through the use of a minimalistic Timber Run-Time system, TinyTimber (TT). The TT kernel ensures state integrity, and performs scheduling of events based on given time-bounds in compliance with the Timber semantics. In this way, we avoid the volatile task of explicitly coding parallelism in terms of processes/threads/semaphores/monitors, and side-step the delicate task to encode time-bounds into priorities. In this paper, the TT kernel design is presented and performance metrics are presented for a number of representative embedded platforms, ranging from small 8-bit to more potent 32-bit micro controllers. The resulting system runs on bare metal, completely free of references to external code (even C-lib) which provides a solid basis for further analysis. In comparison to a traditional thread based real-time operating system for embedded applications (FreeRTOS), TT has tighter timing performance and considerably lower code complexity. In conclusion, TinyTimber is a viable alternative for implementing embedded real-time applications in C today.
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| 4. |
- Lindhult, Johan
(författare)
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Operational Semantics for PLEX : A Basis for Safe Parallelization
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The emerge of multi-core computers implies a major challenge for existing software. Due to simpler cores, the applications will face decreased performance if not executed in parallel. The problem is that much of the software is sequential.Central parts of the AXE telephone exchange system from Ericsson is programmed in the language PLEX. The current software is executed on a single-processor architecture, and assumes non-preemptive execution.This thesis presents two versions of an operational semantics for PLEX; one that models execution on the current, single-processor, architecture, and one that models execution on an assumed shared-memory architecture. A formal semantics of the language is a necessity for ensuring correctness of program analysis, and program transformations.We also report on a case study of the potential memory conflicts that may arise when the existing code is allowed to be executed in parallel. We show that simple static methods are sufficient to resolve many of the potential conflicts, thereby reducing the amount of manual work that probably still needs to be performed in order to adapt the code for parallel processing.
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| 5. |
- Svensson, L., et al.
(författare)
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Are predictors for myocardial infarction the same for women and men when evaluated prior to hospital admission?
- 2006
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Ingår i: Int J Cardiol. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 109:2, s. 241-7
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To describe predictors of myocardial infarction prior to hospital admission in women and men among patients with a suspected acute coronary syndrome without ST-elevation. DESIGN: Prospective observational study in Stockholm and Goteborg, Sweden. RESULTS: Of 433 patients who did fulfill the inclusion criteria 45% were women. Fewer women (17%) than men (26%) developed acute myocardial infarction (AMI) (p=0.054), particularly among patients with initial ST-depression, in whom AMI was developed in 22% of women and 54% of men (p = 0.001). Predictors for infarct development in women were: a history of AMI and advanced age. Among men they were: initial ST-depression or a Q-wave on ECG and elevation of biochemical markers (both recorded on admission of the ambulance crew). There was a significant interaction between gender and the influence of ST-depression on the risk for development of myocardial infarction (p < 0.05). CONCLUSION: Among patients transported with ambulance due to a suspected acute coronary syndrome and no ST-elevation fewer women than men seem to develop AMI particularly among patients with ST-depression. These results suggest that early prediction of myocardial infarction might differ between women and men with acute chest pain.
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| 6. |
- Berglund, Felix, et al.
(författare)
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Acute and long-term renal effects after iodine contrast media-enhanced computerised tomography in the critically ill-a retrospective bi-centre cohort study.
- 2024
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Ingår i: European Radiology. - 0938-7994 .- 1432-1084. ; 34:3, s. 1736-1745
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To determine if current clinical use of iodine contrast media (ICM) for computerised tomography (CT) increases the risk of acute kidney injury (AKI) and long-term decline in renal function in patients treated in intensive care.METHODS: A retrospective bi-centre cohort study was performed with critically ill subjects undergoing either ICM-enhanced or unenhanced CT. AKI was defined and staged based on the Kidney Disease Improve Global Outcome AKI criteria, using both creatinine and urine output criteria. Follow-up plasma creatinine was recorded three to six months after CT to assess any long-term effects of ICM on renal function.RESULTS: In total, 611 patients were included in the final analysis, median age was 65.0 years (48.0-73.0, quartile 1-quartile 3 (IQR)) and 62.5% were male. Renal replacement therapy was used post-CT in 12.9% and 180-day mortality was 31.2%. Plasma creatinine level on day of CT was 100.0 µmol/L (66.0-166.5, IQR) for non-ICM group and 77.0 µmol/L (59.0-109.0, IQR) for the ICM group. The adjusted odds ratio for developing AKI if the patient received ICM was 1.03 (95% confidence interval 0.64-1.66, p = 0.90). No significant association between ICM and increase in plasma creatinine at long-term follow-up was found, with an adjusted effect size of 2.92 (95% confidence interval - 6.52-12.36, p = 0.543).CONCLUSIONS: The results of this study do not indicate an increased risk of AKI or long-term decline in renal function when ICM is used for enhanced CT in patients treated at intensive care units.CLINICAL RELEVANCE STATEMENT: Patients treated in intensive care units had no increased risk of acute kidney injury or persistent decline in renal function after contrast-enhanced CT. This information underlines the need for a proper risk-reward assessment before denying patients a contrast-enhanced CT.KEY POINTS: • Iodine contrast media is considered a risk factor for the development of acute kidney injury. • Patients receiving iodine contrast media did not have an increased incidence of acute kidney injury or persistent decline in renal function. • A more clearly defined risk of iodine contrast media helps guide clinical decisions whether to perform contrast-enhanced CTs or not.
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| 7. |
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| 8. |
- Carlsson, Magnus, et al.
(författare)
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The semantic layers of Timber
- 2003
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Ingår i: Programming languages and systems. - Berlin, Heidelberg : Encyclopedia of Global Archaeology/Springer Verlag. - 9783540205364 - 9783540400189 ; , s. 339-356
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Konferensbidrag (refereegranskat)abstract
- We present a three-layered semantics of Timber, a language designed for programming real-time systems in a reactive, object-oriented style. The innermost layer amounts to a traditional deterministic, pure, functional language, around which we formulate a middle layer of concurrent objects, in terms of a monadic transition semantics. The outermost layer, where the language is married to deadline-driven scheduling theory, is where we define message ordering and CPU allocation to actions. Our main contributions are a formalized notion of a time-constrained reaction, and a demonstration of how scheduling theory, process calculii, and the lambda calculus can be jointly applied to obtain a direct and succinct semantics of a complex, real-world programming language with well-defined real-time behavior.
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| 9. |
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| 10. |
- Dalin, Peter, et al.
(författare)
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Importance of temperature for the performance and biocontrol efficiency of the parasitoid Perilitus brevicollis (Hymenoptera: Braconidae) on Salix
- 2012
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Ingår i: BioControl. - : Springer Science and Business Media LLC. - 1386-6141 .- 1573-8248. ; 57, s. 611-618
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Tidskriftsartikel (refereegranskat)abstract
- With the prospect of warmer temperatures as a consequence of ongoing climate change, it is important to investigate how such increases will affect parasitoids and their top-down suppression of herbivory in agroecosystems. Here we studied how the performance and biocontrol efficiency of the willow "bodyguard" Perilitus brevicollis Haliday (Hymenoptera: Braconidae) were affected at different constant temperatures (10, 15, 20, 25A degrees C) when parasitizing a pest insect, the blue willow beetle (Phratora vulgatissima L., Coleoptera: Chrysomelidae). Parasitism did not reduce herbivory at all at 10A degrees C, indicating poor biocontrol efficiency at low temperatures. At higher temperatures, however, parasitism reduced herbivory substantially, implying that biocontrol may be promoted by a warmer climate. Parasitoid performance (survival and development rate) generally increased with increasing temperature up to 20A degrees C. The only exception was body size, which followed the temperature-size rule and decreased with increasing temperature. Our results indicate that a warmer climate may enhance the biocontrol of the blue willow beetle in environments that currently are cooler than the parasitoid's optimal temperature for development.
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