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- Baxter, Amanda L., et al.
(författare)
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Collaborative experience between scientific software projects using Agile Scrum development
- 2022
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Ingår i: Software, practice & experience. - : John Wiley & Sons. - 0038-0644 .- 1097-024X. ; 52:10, s. 2077-2096
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Tidskriftsartikel (refereegranskat)abstract
- Developing sustainable software for the scientific community requires expertise in software engineering and domain science. This can be challenging due to the unique needs of scientific software, the insufficient resources for software engineering practices in the scientific community, and the complexity of developing for evolving scientific contexts. While open-source software can partially address these concerns, it can introduce complicating dependencies and delay development. These issues can be reduced if scientists and software developers collaborate. We present a case study wherein scientists from the SuperNova Early Warning System collaborated with software developers from the Scalable Cyberinfrastructure for Multi-Messenger Astrophysics project. The collaboration addressed the difficulties of open-source software development, but presented additional risks to each team. For the scientists, there was a concern of relying on external systems and lacking control in the development process. For the developers, there was a risk in supporting a user-group while maintaining core development. These issues were mitigated by creating a second Agile Scrum framework in parallel with the developers' ongoing Agile Scrum process. This Agile collaboration promoted communication, ensured that the scientists had an active role in development, and allowed the developers to evaluate and implement the scientists' software requirements. The collaboration provided benefits for each group: the scientists actuated their development by using an existing platform, and the developers utilized the scientists' use-case to improve their systems. This case study suggests that scientists and software developers can avoid scientific computing issues by collaborating and that Agile Scrum methods can address emergent concerns.
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- Blomgren, Mats, et al.
(författare)
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Idempotent transformations of finite groups
- 2013
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Ingår i: Advances in Mathematics. - : Elsevier BV. - 0001-8708 .- 1090-2082. ; 233:1, s. 56-86
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Tidskriftsartikel (refereegranskat)abstract
- We describe the action of idempotent transformations on finite groups. We show that finiteness is preserved by such transformations and enumerate all possible values such transformations can assign to a fixed finite simple group. This is done in terms of the first two homology groups. We prove for example that except special linear groups, such an orbit can have at most 7 elements. We also study the action of monomials of idempotent transformations on finite groups and show for example that orbits of this action are always finite.
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- Chachólski, Wojciech, et al.
(författare)
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Cellular covers of divisible abelian groups
- 2009
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Ingår i: ALPINE PERSPECTIVES ON ALGEBRAIC TOPOLOGY. - 9780821848395 ; , s. 77-97
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Konferensbidrag (refereegranskat)abstract
- We determine all the possible values of the cellular approximation functor c(A) : cell(A)E -> E, where A is an arbitrary group and E is a divisible abelian group.
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- Chacholski, Wojciech, et al.
(författare)
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The A-core and A-cover of a group
- 2009
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Ingår i: Journal of Algebra. - : Elsevier BV. - 0021-8693 .- 1090-266X. ; 321:2, s. 631-666
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a comprehensive investigation of the cellular approximation functor cell(A) G, in the category of groups. approximating a group G by a group A. We also study related notions such as A-injection, A-generation and A-constructibility of a group G and we find several interesting connections with the Schur multiplier H-2(G, Z). Our constructions are direct and are given in a slow and detailed manner.
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- Flores, J. M., et al.
(författare)
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Evolution of the complex refractive index in the UV spectral region in ageing secondary organic aerosol
- 2014
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 14:11, s. 5793-5806
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Tidskriftsartikel (refereegranskat)abstract
- The chemical and physical properties of secondary organic aerosol (SOA) formed by the photochemical degradation of biogenic and anthropogenic volatile organic compounds (VOC) are as yet still poorly constrained. The evolution of the complex refractive index (RI) of SOA, formed from purely biogenic VOC and mixtures of biogenic and anthropogenic VOC, was studied over a diurnal cycle in the SAPHIR photochemical outdoor chamber in Julich, Germany. The correlation of RI with SOA chemical and physical properties such as oxidation level and volatility was examined. The RI was retrieved by a newly developed broadband cavity-enhanced spectrometer for aerosol optical extinction measurements in the UV spectral region (360 to 420 nm). Chemical composition and volatility of the particles were monitored by a high-resolution time-of-flight aerosol mass spectrometer, and a volatility tandem differential mobility analyzer. SOA was formed by ozonolysis of either (i) a mixture of biogenic VOC (alpha-pinene and limonene), (ii) biogenic VOC mixture with subsequent addition of an anthropogenic VOC (p-xylene-d(10)), or (iii) a mixture of biogenic and anthropogenic VOC. The SOA aged by ozone/OH reactions up to 29.5 h was found to be non-absorbing in all cases. The SOA with p-xylene-d(10) showed an increase of the scattering component of the RI correlated with an increase of the O / C ratio and with an increase in the SOA density. There was a greater increase in the scattering component of the RI when the SOA was produced from the mixture of biogenic VOCs and anthropogenic VOC than from the sequential addition of the VOCs after approximately the same ageing time. The increase of the scattering component was inversely correlated with the SOA volatility. Two RI retrievals determined for the pure biogenic SOA showed a constant RI for up to 5 h of ageing. Mass spectral characterization shows the three types of the SOA formed in this study have a significant amount of semivolatile components. The influence of anthropogenic VOCs on the oxygenated organic aerosol as well as the atmospheric implications are discussed.
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- Lissek, T, et al.
(författare)
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Building Bridges through Science
- 2017
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Ingår i: Neuron. - : Elsevier BV. - 1097-4199 .- 0896-6273. ; 96:4, s. 730-735
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Tidskriftsartikel (refereegranskat)
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