| 1. |
- Åsberg, Mikael, et al.
(författare)
-
Fast Linux Bootup using Non-Intrusive Methods for Predictable Industrial Embedded Systems
- 2013
-
Konferensbidrag (refereegranskat)abstract
- Fast kernel boot-time is one of the major concerns in industrial embedded systems. Application domains where boot time is relevant include (among others) automation, automotive, avionics etc. Linux is one of the big players among operating system solutions for general embedded systems, hence, a relevant question is how fast Linux can boot on typical hardware platforms (ARM9) used in such industrial systems. One important constraint is that this boot-time optimization should be as non-intrusive as possible. The reason for this comes from the fact that industrial embedded systems typically have high demands on reliability and stability. For example, adding, removing or changing critical source-code (such as kernel or initialization code) is impermissible. This paper shows the steps towards a fast-booting Linux kernel using non-intrusive methods. Moreover, targeting embedded systems with temporal constraints, the paper shows how fast the real-time scheduling framework ExSched can be loaded and started during bootup. This scheduling framework supports several real-time scheduling algorithms (user defined, multi-core, partitioned, fixed-priority periodic tasks etc.) and it does not modify the Linux kernel source code. Hence, the non-intrusive bootup optimization methods together with the unmodified Linux kernel and the non-patched real-time scheduler module offers both reliability and predictability.
|
|
| 2. |
|
|
| 3. |
- Behnam, Moris, et al.
(författare)
-
Synchronization protocols for hierarchical real-time scheduling frameworks
- 2008
-
Ingår i: Proceedings of the 1st Workshop on Compositional Theory and Technology for Real-Time Embedded Systems (CRTS'08) in conjunction with the 29th IEEE International Real-Time Systems Symposium (RTSS'08), Barcelona, Spain.
-
Konferensbidrag (refereegranskat)
|
|
| 4. |
- Behnam, Moris, et al.
(författare)
-
Towards Hierarchical Scheduling in VxWorks
- 2008
-
Ingår i: OSPERT 2008, Proceedings of the Fourth International Workshop on Operating Systems Platforms for Embedded Real-Time Applications. ; , s. 63-72
-
Konferensbidrag (refereegranskat)abstract
- Over the years, we have worked on hierarchical schedulingframeworks from a theoretical point of view. In thispaper we present our initial results of the implementationof our hierarchical scheduling framework in a commercialoperating system VxWorks. The purpose of the implementationis twofold: (1) we would like to demonstrate feasibilityof its implementation in a commercial operating system,without having to modify the kernel source code, and (2) wewould like to present detailed figures of various key propertieswith respect to the overhead of the implementation.During the implementation of the hierarchical scheduler,we have also developed a number of simple task schedulers.We present details of the implementation of Rate-Monotonic(RM) and Earliest Deadline First (EDF) schedulers. Finally,we present the design of our hierarchical schedulingframework, and we discuss our current status in the project.
|
|
| 5. |
- Hallmans, Daniel, et al.
(författare)
-
Towards using the Graphics Processing Unit (GPU) for Embedded Systems
- 2012
-
Ingår i: IEEE Symposium on Emerging Technologies and Factory Automation, ETFA 2012. ; , s. Article number: 6489715-
-
Konferensbidrag (refereegranskat)abstract
- The Graphics Processing Unit (GPU) is becoming a very powerful platform to accelerate graphics and dataparallel compute-intensive applications. It gives a high performance and at the same time it has a low power consumption. This combination is of high performance and low power consumption is useful when it comes to building an embedded system. In this paper we are looking at the possibility to use a combination of CPU and GPU to provide performance metrics that are required in an embedded system. In particular we look at requirements inherent in the process and power industries where we believe that the GPU has the potential to be a useful and natural element in future embedded system architectures.
|
|
| 6. |
- Kazantseva, Nataliya, et al.
(författare)
-
Micromechanisms of Deformation and Fracture in Porous L-PBF 316L Stainless Steel at Different Strain Rates
- 2021
-
Ingår i: Metals. - : MDPI. - 2075-4701. ; 11:11
-
Tidskriftsartikel (refereegranskat)abstract
- The process of an unstable plastic flow associated with the strain rate sensitivity of mechanical properties was studied in porous 316L austenitic steel samples manufactured by laser powder bed fusion (L-PBF). Different micromechanisms of deformation and fracture of porous samples dependent on strain rate were found. It was found that despite the porosity, the specimens showed high strength, which increased with the loading rate. Porosity led to lower ductility of the studied specimens, in comparison with literature data for low porous 316L L-PBF samples and resulted in de-localization of plastic deformation. With an increase in strain rate, nucleation of new pores was less pronounced, so that at the highest strain rate of 8 x 10(-3) s(-1), only pore coalescence was observed as the dominating microscopic mechanism of ductile fracture.
|
|
| 7. |
- Krakhmalev, Pavel, 1973-, et al.
(författare)
-
Influence of heat treatment under hot isostatic pressing (HIP) on microstructure of intermetallic-reinforced tool steel manufactured by laser powder bed fusion
- 2020
-
Ingår i: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 772
-
Tidskriftsartikel (refereegranskat)abstract
- Microstructure and properties of as-built laser powder bed fusion (LPBF) steels differ from the conventional ones, and they may contain some porosity and lack of fusion. Therefore, post-treatments, including hot isostatic pressing (HIP), are used to density the material, and tailor the properties of the final product. Usually, HIP is performed as an operation separate from heat treatment. In the present investigation a new approach was used, in which the whole cycle of the heat treatment was carried out in HIP under pressure, and the influence of HIP on microstructure of an advanced stainless maraging tool steel manufactured by LPBF was investigated. For a comparison, a conventional steel grade of the same chemical composition, after a heat treatment at the same temperature-time conditions, was also characterized. The microstructure of the steel was investigated by means of advanced microscopy and atom probe tomography. The influence of the manufacturing route, heat treatment and HIP on microstructure, austenitic phase fraction and size distribution of precipitates was investigated, and the role of high pressure in stabilization of austenite in the microstructure was discussed. It was concluded that since HIP influences phase transformations, a fundamental understanding of the influence of HIP on microstructure is nececcary, and development of new post processing regimes guaranteeing the best performance of the material is required.
|
|
| 8. |
- Maripuu, Martin, 1973-
(författare)
-
Hypocortisolism in recurrent affective disorders
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bipolar disorders and recurrent depressions are two common psychiatric disorders with a life time prevalence of approximately 1% and 8%, respectively. Despite treatment these patients suffer from affective symptoms up to 50% of the time, resulting in lower well-being. The average life length is also reduced with 10-15 years, mainly attributable to suicide and cardiovascular disease. Increased stress is one of many factors that have been shown to be linked to an increased risk for developing affective disorders and some comorbid somatic conditions such as metabolic disturbances and cardiovascular disease. An increased stress level is known to cause hyperactivity of the hypothalamic-pituitary-adrenal-axis (HPA-axis) with increased cortisol secretion. Hyperactivity of the HPA-axis (or hypercortisolism) is one of the most replicated neurobiological finding in depression. In other stress related disorders it has however been shown that prolonged stress over long periods of time can lead to a state of low HPA-axis activity, hypocortisolism. Since persons with recurrent affective disorders such as bipolar disorder and recurrent depression are exposed to a high degree of recurrent and chronic stress it could be expected that in addition to hypercortisolism, a state of hypocortisolism could also develop in these disorders, potentially exerting an influence upon the psychological and somatic wellbeing among these patients.The major aim of this thesis was to evaluate whether hypocortisolism is related to relevant psychiatric and somatic phenotypes in recurrent affective disorders.In bipolar disorder, individuals with hypocortisolism exhibited a higher degree of depression and low quality of life compared to patients with normal HPA-axis activity. In recurrent depression, individuals with hypocortisolism exhibited shorter leukocyte telomere length than patients with normal or high HPA-axis activity, which is an indication of an accelerated aging process. In a sample of both bipolar and recurrent depression patients, hypocortisolism was associated with an increased proportion of obesity, dyslipidemia and metabolic syndrome compared with patients with normal or high HPA-axis activity. Patients with recurrent depression showed a higher occurrence of hypocortisolism than the control sample representative of the general population. Patients with bipolar disorder showed a similar occurrence of hypocortisolism as the control sample. Among bipolar disorder patients with a low degree of lifetime with lithium prophylaxis, there was an inverse correlation between age and HPA-axis activity. In contrast, among patients with a higher degree of lifetime with lithium prophylaxis as well as among the controls, there was no correlation between age and HPA-axis activity. Accordingly, hypocortisolism was most common among older patients with a low degree of lifetime with lithium prophylaxis. In conclusion, hypocortisolism in both recurrent depression and bipolar disorder was associated with multiple clinically-relevant phenotypes. Additionally it was shown for bipolar disorder patients that increasing age was a risk factor for hypocortisolism and that prophylactic lithium treatment was a protective factor. It is argued that the protective effect of lithium towards the HPA-axis is attributable to its mood-stabilizing effect, which in turn reduces the chronic stress level. These results provide new insight into the role of hypocortisolism and chronic stress in recurrent affective disorders warranting further studies and hopefully providing clues to improved treatment strategies.
|
|
| 9. |
- Merkel, Magnus, et al.
(författare)
-
Automatic Extraction and Manual Validation of Hierarchical Patent Terminology
- 2009
-
Ingår i: NORDTERM 16. Ontologier og taksonomier.. - Copenhagen, Denmark : Copenhagen Business School Press. - 9788799457700 ; , s. 249-262
-
Konferensbidrag (refereegranskat)abstract
- Several methods can be applied to create a set of validated terms from existing documents. In this paper we describe an automatic bilingual term candidate extraction method, and the validation process used to create a hierarchical patent terminology. The process described was used to extract terms from patent texts, commissioned by the Swedish Patent Office with the purpose of using the terms for machine translation. Information on the correct linguistic inflection patterns and hierarchical partitioning of terms based on their use are of utmost importance.The process contains six phases, 1) Analysis of the source material and system configuration; 2) Term candidate extraction; 3) Term candidate filtering and initial linguistic validation; 4) Manual validation by domain experts; 5) Final linguistic validation; and 6) Publishing the validated terms.Input to the extraction process consisted of more than 91 000 patent document pairs in English and Swedish, 565 million words in English and 450 million words in Swedish. The English documents were supplied in EBD SGML format and the Swedish documents were supplied in OCR processed scans of patent documents. After grammatical and statistical analysis, the documents were word-aligned. Using the word-aligned material, candidate terms were extracted based on linguistic patterns. 750 000 term candidates were extracted and stored in a relational database. The term candidates were processed in 8 months resulting in 181 000 unique validated term pairs that were exported into several hierarchically organized OLIF files.
|
|
| 10. |
- Moghaddami Khalilzad, Nima, et al.
(författare)
-
On Adaptive Hierarchical Scheduling of Real-time Systems Using a Feedback Controller
- 2011
-
Ingår i: 3rd Workshop on Adaptive and Reconfigurable Embedded Systems (APRES'11).
-
Konferensbidrag (refereegranskat)abstract
- Hierarchical scheduling provides predictable timing and temporal isolation; two properties desirable in real-time embedded systems. In hierarchically scheduled systems, subsystems should receive a sufficient amount of CPU resources in order to be able to guarantee timing constraints of its internal parts (tasks). In static systems, an exact amount of CPU resource can be allocated to a subsystem. However, in dynamic systems, where execution times of tasks vary considerably during runtime, it is desirable to give a dynamic portion of the CPU given the current load situation. In this paper we present a feedback control approach for adapting the amount of CPU resource that is allocated to subsystems during run-time such that each subsystem receives sufficient resources while keeping the number of deadline violations to a minimum. We also show an example simulation where the controller adapts the budget of a subsystem.
|
|
