TY  - JOUR
A1  - Ilin, Ekaterina
A1  - Poppenhäger, Katja
A1  - Alvarado-Gómez, Julián David
T1  - Localizing flares to understand stellar magnetic fields and space weather in exo-systems
JF  - Astronomische Nachrichten = Astronomical notes
N2  - Stars are uniform spheres, but only to first order. The way in which stellar rotation and magnetism break this symmetry places important observational constraints on stellar magnetic fields, and factors in the assessment of the impact of stellar activity on exoplanet atmospheres. The spatial distribution of flares on the solar surface is well known to be nonuniform, but elusive on other stars. We briefly review the techniques available to recover the loci of stellar flares, and highlight a new method that enables systematic flare localization directly from optical light curves. We provide an estimate of the number of flares we may be able to localize with the Transiting Exoplanet Survey Satellite, and show that it is consistent with the results obtained from the first full sky scan of the mission. We suggest that nonuniform flare latitude distributions need to be taken into account in accurate assessments of exoplanet habitability.
KW  - stars
KW  - activity - stars
KW  - flare - stars
KW  - magnetic fields - methods
KW  - data
KW  - analysis
Y1  - 2022
U6  - https://doi.org/10.1002/asna.20210111
SN  - 1521-3994
VL  - 343
IS  - 4
PB  - Berlin
CY  - Wiley-VCH
ER  - 
TY  - JOUR
A1  - van der Aa, Han
A1  - Leopold, Henrik
A1  - Weidlich, Matthias
T1  - Partial order resolution of event logs for process conformance checking
JF  - Decision support systems : DSS
N2  - While supporting the execution of business processes, information systems record event logs. Conformance checking relies on these logs to analyze whether the recorded behavior of a process conforms to the behavior of a normative specification. A key assumption of existing conformance checking techniques, however, is that all events are associated with timestamps that allow to infer a total order of events per process instance. Unfortunately, this assumption is often violated in practice. Due to synchronization issues, manual event recordings, or data corruption, events are only partially ordered. In this paper, we put forward the problem of partial order resolution of event logs to close this gap. It refers to the construction of a probability distribution over all possible total orders of events of an instance. To cope with the order uncertainty in real-world data, we present several estimators for this task, incorporating different notions of behavioral abstraction. Moreover, to reduce the runtime of conformance checking based on partial order resolution, we introduce an approximation method that comes with a bounded error in terms of accuracy. Our experiments with real-world and synthetic data reveal that our approach improves accuracy over the state-of-the-art considerably.
KW  - process mining
KW  - conformance checking
KW  - partial order resolution
KW  - data
KW  - uncertainty
Y1  - 2020
U6  - https://doi.org/10.1016/j.dss.2020.113347
SN  - 0167-9236
SN  - 1873-5797
VL  - 136
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Dineva, Ekaterina Ivanova
A1  - Verma, Meetu
A1  - Gonzalez Manrique, Sergio Javier
A1  - Schwartz, Pavol
A1  - Denker, Carsten
T1  - Cloud model inversions of strong chromospheric absorption lines using principal component analysis
JF  - Astronomische Nachrichten = Astronomical notes
N2  - High-resolution spectroscopy of strong chromospheric absorption lines delivers nowadays several millions of spectra per observing day, when using fast scanning devices to cover large regions on the solar surface. Therefore, fast and robust inversion schemes are needed to explore the large data volume. Cloud model (CM) inversions of the chromospheric H alpha line are commonly employed to investigate various solar features including filaments, prominences, surges, jets, mottles, and (macro-) spicules. The choice of the CM was governed by its intuitive description of complex chromospheric structures as clouds suspended above the solar surface by magnetic fields. This study is based on observations of active region NOAA 11126 in H alpha, which were obtained November 18-23, 2010 with the echelle spectrograph of the vacuum tower telescope at the Observatorio del Teide, Spain. Principal component analysis reduces the dimensionality of spectra and conditions noise-stripped spectra for CM inversions. Modeled H alpha intensity and contrast profiles as well as CM parameters are collected in a database, which facilitates efficient processing of the observed spectra. Physical maps are computed representing the line-core and continuum intensity, absolute contrast, equivalent width, and Doppler velocities, among others. Noise-free spectra expedite the analysis of bisectors. The data processing is evaluated in the context of "big data," in particular with respect to automatic classification of spectra.
KW  - sun
KW  - activity - sun
KW  - atmosphere - sun
KW  - chromosphere - methods
KW  - data
KW  - analysis - techniques
KW  - spectroscopic - astronomical databases
KW  - miscellaneous
Y1  - 2020
U6  - https://doi.org/10.1002/asna.202013652
SN  - 0004-6337
SN  - 1521-3994
VL  - 341
IS  - 1
SP  - 64
EP  - 78
PB  - Wiley-VCH Verl.
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Khider, D.
A1  - Emile-Geay, J.
A1  - McKay, N. P.
A1  - Gil, Y.
A1  - Garijo, D.
A1  - Ratnakar, V
A1  - Alonso-Garcia, M.
A1  - Bertrand, S.
A1  - Bothe, O.
A1  - Brewer, P.
A1  - Bunn, A.
A1  - Chevalier, M.
A1  - Comas-Bru, L.
A1  - Csank, A.
A1  - Dassie, E.
A1  - DeLong, K.
A1  - Felis, T.
A1  - Francus, P.
A1  - Frappier, A.
A1  - Gray, W.
A1  - Goring, S.
A1  - Jonkers, L.
A1  - Kahle, M.
A1  - Kaufman, D.
A1  - Kehrwald, N. M.
A1  - Martrat, B.
A1  - McGregor, H.
A1  - Richey, J.
A1  - Schmittner, A.
A1  - Scroxton, N.
A1  - Sutherland, E.
A1  - Thirumalai, Kaustubh
A1  - Allen, K.
A1  - Arnaud, F.
A1  - Axford, Y.
A1  - Barrows, T.
A1  - Bazin, L.
A1  - Birch, S. E. Pilaar
A1  - Bradley, E.
A1  - Bregy, J.
A1  - Capron, E.
A1  - Cartapanis, O.
A1  - Chiang, H-W
A1  - Cobb, K. M.
A1  - Debret, M.
A1  - Dommain, Réne
A1  - Du, J.
A1  - Dyez, K.
A1  - Emerick, S.
A1  - Erb, M. P.
A1  - Falster, G.
A1  - Finsinger, W.
A1  - Fortier, D.
A1  - Gauthier, Nicolas
A1  - George, S.
A1  - Grimm, E.
A1  - Hertzberg, J.
A1  - Hibbert, F.
A1  - Hillman, A.
A1  - Hobbs, W.
A1  - Huber, M.
A1  - Hughes, A. L. C.
A1  - Jaccard, S.
A1  - Ruan, J.
A1  - Kienast, M.
A1  - Konecky, B.
A1  - Le Roux, G.
A1  - Lyubchich, V
A1  - Novello, V. F.
A1  - Olaka, L.
A1  - Partin, J. W.
A1  - Pearce, C.
A1  - Phipps, S. J.
A1  - Pignol, C.
A1  - Piotrowska, N.
A1  - Poli, M-S
A1  - Prokopenko, A.
A1  - Schwanck, F.
A1  - Stepanek, C.
A1  - Swann, G. E. A.
A1  - Telford, R.
A1  - Thomas, E.
A1  - Thomas, Z.
A1  - Truebe, S.
A1  - von Gunten, L.
A1  - Waite, A.
A1  - Weitzel, N.
A1  - Wilhelm, B.
A1  - Williams, J.
A1  - Winstrup, M.
A1  - Zhao, N.
A1  - Zhou, Y.
T1  - PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data
JF  - Paleoceanography and paleoclimatology
N2  - The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches.
KW  - standards
KW  - FAIR
KW  - paleoclimate
KW  - paleoceanography
KW  - data
KW  - best practices
Y1  - 2019
U6  - https://doi.org/10.1029/2019PA003632
SN  - 2572-4517
SN  - 2572-4525
VL  - 34
IS  - 10
SP  - 1570
EP  - 1596
PB  - American Geophysical Union
CY  - Washington
ER  -