| 1. |
- Wetzel, G., et al.
(författare)
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Validation of MIPAS-ENVISAT H2O operational data collected between July 2002 and March 2004
- 2013
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 13:11, s. 5791-5811
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Tidskriftsartikel (refereegranskat)abstract
- Water vapour (H2O) is one of the operationally retrieved key species of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard the Environmental Satellite (ENVISAT) which was launched into its sun-synchronous orbit on 1 March 2002 and operated until April 2012. Within the MIPAS validation activities, independent observations from balloons, aircraft, satellites, and ground-based stations have been compared to European Space Agency (ESA) version 4.61 operational H2O data comprising the time period from July 2002 until March 2004 where MIPAS measured with full spectral resolution. No significant bias in the MIPAS H2O data is seen in the lower stratosphere (above the hygropause) between about 15 and 30 km. Differences of H2O quantities observed by MIPAS and the validation instruments are mostly well within the combined total errors in this altitude region. In the upper stratosphere (above about 30 km), a tendency towards a small positive bias (up to about 10 %) is present in the MIPAS data when compared to its balloon-borne counterpart MIPAS-B, to the satellite instruments HALOE (Halogen Occultation Experiment) and ACE-FTS (Atmospheric Chemistry Experiment, Fourier Transform Spectrometer), and to the millimeter-wave airborne sensor AMSOS (Airborne Microwave Stratospheric Observing System). In the mesosphere the situation is unclear due to the occurrence of different biases when comparing HALOE and ACE-FTS data. Pronounced deviations between MIPAS and the correlative instruments occur in the lowermost stratosphere and upper troposphere, a region where retrievals of H2O are most challenging. Altogether it can be concluded that MIPAS H2O profiles yield valuable information on the vertical distribution of H2O in the stratosphere with an overall accuracy of about 10 to 30% and a precision of typically 5 to 15% - well within the predicted error budget, showing that these global and continuous data are very valuable for scientific studies. However, in the region around the tropopause retrieved MIPAS H2O profiles are less reliable, suffering from a number of obstacles such as retrieval boundary and cloud effects, sharp vertical discontinuities, and frequent horizontal gradients in both temperature and H2O volume mixing ratio (VMR). Some profiles are characterized by retrieval instabilities.
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| 2. |
- Casimiro, A.C., et al.
(författare)
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A kernel-based architecture for safe cooperative vehicular functions
- 2014
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Ingår i: Proceedings of the 9th IEEE International Symposium on Industrial Embedded Systems, SIES 2014. - 9781479940233 ; , s. 228-237
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Konferensbidrag (refereegranskat)abstract
- Future vehicular systems will be able to cooperate in order to perform many functions in a more effective and efficient way. However, achieving predictable and safe coordination of vehicles that autonomously cooperate in open and uncertain environments is a challenging task. Traditional solutions for achieving safety either impose restrictions on performance or require costly resources to deal with the worst case situations. In this paper, we describe a generic architectural pattern that addresses this problem. We consider that cooperative functions can be executed with multiple levels of service, and we rely on a safety kernel to manage the service level in run-time. A set of safety rules defined in design-time determine conditions under which the cooperative function can be performed safely in each level of service. The paper provides details of our implementation of this safety kernel, covering both hardware and software aspects. It also presents an example application of the proposed solutions in the development of a demonstrator using scaled vehicles.
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| 3. |
- Casimiro, A.C., et al.
(författare)
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The KARYON project: Predictable and safe coordination in cooperative vehicular systems
- 2013
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Ingår i: Proceedings of the International Conference on Dependable Systems and Networks. - 9781479901814
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Konferensbidrag (refereegranskat)abstract
- KARYON, a kernel-based architecture for safety-critical control, is a European project that proposes a new perspective to improve performance of smart vehicle coordination. The key objective of KARYON is to provide system solutions for predictable and safe coordination of smart vehicles that autonomously cooperate and interact in an open and inherently uncertain environment. One of the main challenges is to ensure high performance levels of vehicular functionality in the presence of uncertainties and failures. This paper describes some of the steps being taken in KARYON to address this challenge, from the definition of a suitable architectural pattern to the development of proof-of-concept prototypes intended to show the applicability of the KARYON solutions. The project proposes a safety architecture that exploits the concept of architectural hybridization to define systems in which a small local safety kernel can be built for guaranteeing functional safety along a set of safety rules. KARYON is also developing a fault model and fault semantics for distributed, continuous-valued sensor systems, which allows abstracting specific sensor faults and facilitates the definition of safety rules in terms of quality of perception. Solutions for improved communication predictability are proposed, ranging from network inaccessibility control at lower communication levels to protocols for assessment of cooperation state at the process level. KARYON contributions include improved simulation and fault-injection tools for evaluating safety assurance according to the ISO 26262 safety standard. The results will be assessed using selected use cases in the automotive and avionic domains. © 2013 IEEE.
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| 4. |
- Casimiro, A.C., et al.
(författare)
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Vehicular coordination via a safety kernel in the gulliver test-bed
- 2014
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Ingår i: Proceedings - International Conference on Distributed Computing Systems, 014 IEEE 34th International Conference on Distributed Computing Systems Workshops, ICDCSW 2014, Madrid, Spain, 30 June - 3 July 2014. - 9781479941810 ; 30, s. 167-176
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Konferensbidrag (refereegranskat)abstract
- Cooperative vehicular systems base their coordination on inherently uncertain inter-vehicle communications. Safe solutions that do not properly manage uncertainty, lead to inefficient outcomes. We consider that cooperative functions can be executed with several service levels, and we use the system architectural concept of safety kernel for managing the service level that achieves the best possible performance while keeping the system safe. We use the Gulliver test-bed for demonstrating the safety kernel concept by means of a pilot system implementation on scaled vehicles with sensors and communication capabilities. The demonstrated architecture incorporates: (1) a local dynamic map (LDM) that uses local and remote sensory information for calculating the location of nearby objects, (2) a safety kernel to manage the service levels, (3) a cooperative level of service evaluator that allows vehicles to reach agreement on a common service level and, finally, (4) a driver manager that executes in accordance to the cooperative level of service when determining how to calculate the trajectory. This paper explains how the different components considered in the architectural concept operate, and shows how it is possible to use (similar to existing) trajectory planning algorithms when implementing the concept.
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| 5. |
- Dieterich, L. C., et al.
(författare)
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alphaB-Crystallin regulates expansion of CD11b(+)Gr-1(+) immature myeloid cells during tumor progression
- 2013
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Ingår i: The FASEB Journal. - : FASEB. - 0892-6638 .- 1530-6860. ; 27:1, s. 151-62
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Tidskriftsartikel (refereegranskat)abstract
- The molecular chaperone alphaB-crystallin has emerged as a target for cancer therapy due to its expression in human tumors and its role in regulating tumor angiogenesis. alphaB-crystallin also reduces neuroinflammation, but its role in other inflammatory conditions has not been investigated. Here, we examined whether alphaB-crystallin regulates inflammation associated with tumors and ischemia. We found that CD45(+) leukocyte infiltration is 3-fold increased in tumors and ischemic myocardium in alphaB-crystallin-deficient mice. Notably, alphaB-crystallin is prominently expressed in CD11b(+) Gr-1(+) immature myeloid cells (IMCs), known as regulators of angiogenesis and immune responses, while lymphocytes and mature granulocytes show low alphaB-crystallin expression. alphaB-Crystallin deficiency results in a 3-fold higher accumulation of CD11b(+) Gr-1(+) IMCs in tumors and a significant rise in CD11b(+) Gr-1(+) IMCs in spleen and bone marrow. Similarly, we noted a 2-fold increase in CD11b(+) Gr-1(+) IMCs in chronically inflamed livers in alphaB-crystallin-deficient mice. The effect of alphaB-crystallin on IMC accumulation is limited to pathological conditions, as CD11b(+) Gr-1(+) IMCs are not elevated in naive mice. Through ex vivo differentiation of CD11b(+) Gr-1(+) cells, we provide evidence that alphaB-crystallin regulates systemic expansion of IMCs through a cell-intrinsic mechanism. Our study suggests a key role of alphaB-crystallin in limiting expansion of CD11b(+) Gr-1(+) IMCs in diverse pathological conditions.
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