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- Sun, Vivian Z., et al.
(författare)
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Overview and Results From the Mars 2020 Perseverance Rover's First Science Campaign on the Jezero Crater Floor
- 2023
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Ingår i: Journal of Geophysical Research: Planets. - : John Wiley and Sons Inc. - 2169-9097 .- 2169-9100. ; 128:6
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Tidskriftsartikel (refereegranskat)abstract
- The Mars 2020 Perseverance rover landed in Jezero crater on 18 February 2021. After a 100-sol period of commissioning and the Ingenuity Helicopter technology demonstration, Perseverance began its first science campaign to explore the enigmatic Jezero crater floor, whose igneous or sedimentary origins have been much debated in the scientific community. This paper describes the campaign plan developed to explore the crater floor's Máaz and Séítah formations and summarizes the results of the campaign between sols 100–379. By the end of the campaign, Perseverance had traversed more than 5 km, created seven abrasion patches, and sealed nine samples and a witness tube. Analysis of remote and proximity science observations show that the Máaz and Séítah formations are igneous in origin and composed of five and two geologic members, respectively. The Séítah formation represents the olivine-rich cumulate formed from differentiation of a slowly cooling melt or magma body, and the Máaz formation likely represents a separate series of lava flows emplaced after Séítah. The Máaz and Séítah rocks also preserve evidence of multiple episodes of aqueous alteration in secondary minerals like carbonate, Fe/Mg phyllosilicates, sulfates, and perchlorate, and surficial coatings. Post-emplacement processes tilted the rocks near the Máaz-Séítah contact and substantial erosion modified the crater floor rocks to their present-day expressions. Results from this crater floor campaign, including those obtained upon return of the collected samples, will help to build the geologic history of events that occurred in Jezero crater and provide time constraints on the formation of the Jezero delta.
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| 2. |
- Johnson, Pontus, et al.
(författare)
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Can the Common Vulnerability Scoring System be Trusted? : A Bayesian Analysis
- 2018
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Ingår i: IEEE Transactions on Dependable and Secure Computing. - : IEEE Press. - 1545-5971 .- 1941-0018. ; 15:6, s. 1002-1015
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Tidskriftsartikel (refereegranskat)abstract
- The Common Vulnerability Scoring System (CVSS) is the state-of-the art system for assessing software vulnerabilities. However, it has been criticized for lack of validity and practitioner relevance. In this paper, the credibility of the CVSS scoring data found in five leading databases – NVD, X-Force, OSVDB, CERT-VN, and Cisco – is assessed. A Bayesian method is used to infer the most probable true values underlying the imperfect assessments of the databases, thus circumventing the problem that ground truth is not known. It is concluded that with the exception of a few dimensions, the CVSS is quite trustworthy. The databases are relatively consistent, but some are better than others. The expected accuracy of each database for a given dimension can be found by marginalizing confusion matrices. By this measure, NVD is the best and OSVDB is the worst of the assessed databases.
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| 3. |
- Johnson, Pontus, et al.
(författare)
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Modeling and analyzing systems-of-systems in the Multi-Attribute Prediction Language (MAPL)
- 2016
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Ingår i: Proceedings - 4th International Workshop on Software Engineering for Systems-of-Systems, SESoS 2016. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450341721 ; , s. 1-7
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Konferensbidrag (refereegranskat)abstract
- The Multi-Attribute Prediction Language (MAPL), an analysis metamodel for non-functional qualities of systems-ofsystems, is introduced. MAPL features analysis in five nonfunctional areas: service cost, service availability, data accuracy, application coupling, and application size. In addition, MAPL explicitly includes utility modeling to make tradeoffs between the qualities. The paper introduces how each of the five non-functional qualities is modeled and quantitatively analyzed based on the ArchiMate standard for enterprise architecture modeling and the previously published Predictive, Probabilistic Architecture Modeling Framework, building on the well-known UML and OCL formalisms. The main contribution of MAPL lies in combining all five nonfunctional analyses into a single unified framework.
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| 4. |
- Lagerström, Robert, 1981-, et al.
(författare)
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Automated Probabilistic System Architecture Analysis in the Multi-Attribute Prediction Language (MAPL) : Iteratively Developed using Multiple Case Studies
- 2017
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Ingår i: International Journal of Complex Systems Informatics and Modeling Quarterly (CSIMQ). - : Riga Technical University. - 2255-9922. ; June/July:11, s. 38-68
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Tidskriftsartikel (refereegranskat)abstract
- The Multi-Attribute Prediction Language (MAPL), an analysis metamodel for non-functional qualities of system architectures, is introduced. MAPL features automate analysis in five non-functional areas: service cost, service availability, data accuracy, application coupling, and application size. In addition, MAPL explicitly includes utility modeling to make trade-offs between the qualities. The article introduces how each of the five non-functional qualities are modeled and quantitatively analyzed based on the ArchiMate standard for enterprise architecture modeling and the previously published Predictive, Probabilistic Architecture Modeling Framework, building on the well-known UML and OCL formalisms. The main contribution of MAPL lies in the probabilistic use of multi-attribute utility theory for the trade-off analysis of the non-functional properties. Additionally, MAPL proposes novel model-based analyses of several non-functional attributes. We also report how MAPL has iteratively been developed using multiple case studies.
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| 5. |
- Lillbacka, Robert, et al.
(författare)
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A model for short crack propagation in polycrystalline materials.
- 2006
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Ingår i: Engineering Fracture Mechanics. ; 73:2, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- A model for microstructurally short crack propagation in a grain structure of a polycrystalline material is developed. The crack propagation model is based on a crystal plasticity model and a microstructurally short crack propagation model in the spirit of the model by Navarro and de los Rios [A model for short fatigue crack propagation with an interpretation of the short–long crack transition. Fatigue Fract Eng Mater Struct 1987;10:169–86]. Numerical examples, where the combined crystal plasticity and crack propagation model is implemented in a model of a microstructure representing a duplex stainless steel, concludes the paper. Results showing how the misorientation of the crack- and slip-directions between two adjacent austenitic grains influences the crack propagation rate, as the crack propagates across their common grain boundary, are given.
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