Representing local dynamics within water resource systems through a data-driven emulation approach

Growing population and socio-economic activities along with looming effects of climate change have led to enormous pressures on water resource systems. To diagnose and quantify potential vulnerabilities, effective tools are required to represent the interactions between limited water availability and competing water demands across a range of spatial and temporal scales. Despite significant progresses in integrated modeling of water resource systems, the majority of existing models are still unable to fully describe the contemplating dynamics within and between elements of water resource systems across all relevant scales and/or variables. Here, a data-driven approach is suggested to represent local details of a water resource system through emulating an existing water resource system model, in which these details have been missed. This is through advising a set of interconnected functional mappings, i.e. integrated emulators, parameterized using the simulation results of the existing model at a common scale and/or variable but can support process representation with finer resolution and/or details. The proposed approach is applied to a complex water resource system in Southern Alberta, Canada, to provide a detailed understanding of the system’s dynamics at the Oldman Reservoir, which is the key to provision of effective water resource management in this semi-arid and already stressed cold region. By proposing a rigorous setup/falsification procedure, a set of alternative hypotheses for emulators describing the local dynamics of local irrigation demand and withdrawals along with reservoir release and evaporation is developed. Findings show that emulators formed using Artificial Neural Networks mainly outperform simpler emulators developed for the variables considered. The non-falsified emulators are then coupled to represent the local dynamics of the water resource system at the reservoir location, considering the underlying interplays with hydro-climatological conditions and human decision on the irrigation area. It is found that emulators with input variables identified through expert knowledge can outperform fully data-driven emulators in which proxies were selected based on an input variable selection method. The top non-falsified coupled models are able to capture the dynamic of lake evaporation, water withdrawal, irrigation demand, reservoir release and storage with coefficient of determination of 0.80 to 0.82, 0.45 to 0.55, 0.52 to 0.59, 0.98 to 0.99 and 0.72 to 0.88, respectively. The practical utility of the proposed approach is demonstrated through an impact assessment study by analysing four performance criteria, corresponding to reservoir’s storage, local irrigation demand, number of spill events and median reservoir release, in three stress-tests. These stress tests asses the local sensitivity of water resource system at the Oldman reservoir at three different levels, corresponding to (1) changing incoming streamflow to the basin in a bottom-up approach; (2) joint scenario of changing streamflow and warming climate, using a coupled bottom-up/top-down approach; and (3) specific changes in incoming streamflow, climate and irrigation area in a heuristic approach. For the first experimentation, weekly realizations for possible water availability are stochastically reconstructed and fed into the top non-falsified integrated emulator. By defining warm/dry, historical and cold/wet flow conditions, we found through alteration from dry to wet regime condition, the expected number of low storage duration is not changed, and expected annual water deficit is declined. Moreover, the expected number of spill events increases whereas median reservoir release increases. In the next impact assessment study, different scenarios of warming climate obtained from NASA-NEX downscaled global climate projections and the joint impact of changing streamflow and temperature on the system’s behaviour is evaluated. This assessment demonstrated that in warmer climate, the expected number of low storage duration in dry condition increases whereas in historical and wet conditions, the low storage duration does not change. In addition, the expected annual water deficit increases while the expected number of spill events decreases in the three flow regime conditions. Moreover, the expected median reservoir release increases in the dry, historical and wet regime conditions. In the final level of assessment, vulnerability of the system under changing streamflow, climate including temperature and precipitation and changing irrigation area is assessed. Results show that increasing irrigation area combined with declining inflow can considerably increase the duration of low reservoir storage in the Oldman Reservoir. Increasing temperature can lead to decline in both reservoir storage and outflow. In addition, when combined with declining inflow, increasing temperature can severely increase the annual water deficit for irrigation sector. Furthermore, it is noted that although the performance of unfalsified models are identical in representing the dynamics of the Oldman Reservoir under the historical data, but assessment can be slightly to moderately different depending on the defined scenarios of change. This is due to the choice of model configuration and can address the uncertainty regarding the system’s behaviour. Our study shows the promise of data-driven emulation approach as a tool for developing more enhanced water resource system models to face emerging management problems in the era of change

Enlarging the possibility space for scientific model-based explanation

Two prominent views in the scientific explanation literature are: (1) that scientific explanations should be ontic or track causal or constitutive relations between the explanans and explanandum; (2) Idealizations in scientific models can be either epistemically dispensable or indispensable in principle. (1) manifests in the requirements which proponents of that view hold for scientific models to be deemed explanatory. Per these advocates, scientific models must not only track causal or constitutive relations but must include some mapping from the model components to the target system. (2) represents something like the current state of play for understanding the place of idealizations in scientific models and involves the longstanding issue of intertheoretic reduction. Idealizations can either be epistemically indispensable (that is not derivable from or reducible to) the relevant micro-level theory or epistemically dispensable in principle. The following project aims to rebut both of these views, thereby seeking to enlarge the possibility space for scientific explanation. For this reason, this project gestures towards and develops new dimensions for scientific model-based explanation. Pace (1), there are many scientific models which do not track ontic or causal relations but are nevertheless explanatory. The first chapter considers a cognitive dynamical model --the HKB model of bimanual coordination-- which fails these requirements for explanation but is one which I claim can still be shown to be explanatory. This represents a promising bit of evidence which can be marshalled and directed against this commitment. Along the lines of (1), proponents of this requirement claim that scientific models must be ontic or risk facing a problematic "directionality problem." The second chapter provides a route of response for the advocate of non-ontic scientific explanations, demonstrating how this problem can be resolved along pragmatic lines. Finally, the partition of the possibility space for understanding the role of idealizations in scientific models encapsulated in (2) is challenged in the third chapter. Therein, a certain species of idealization -continuum idealizations- are discussed and a pragmatic and deflationary approach to the issue of intertheoretic reduction is argued for. These chapters all serve to demonstrate countervailing considerations which, if successful, act as important challenges for the veracity of both (1) and (2). Rather than achieving a mere refutation of these commitments, the success of this project calls for a re-imagining and enlargement of the possibility space for scientific model-based explanations.Includes bibliographical references

14th Conference on Dynamical Systems Theory and Applications DSTA 2017 ABSTRACTS

From Preface: This is the fourteen time when the conference “Dynamical Systems – Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and the Ministry of Science and Higher Education. It is a great pleasure that our invitation has been accepted by so many people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcome nearly 250 persons from 38 countries all over the world. They decided to share the results of their research and many years experiences in the discipline of dynamical systems by submitting many very interesting papers. This booklet contains a collection of 375 abstracts, which have gained the acceptance of referees and have been qualified for publication in the conference proceedings [...]

Computer Aided Verification

This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency

Mathematical and Numerical Aspects of Dynamical System Analysis

From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

Effects of ionizing radiation on organotypic slice cultures

Ziel dieser Arbeit war, die Reaktion von biologischen Gewebeproben auf dünn- und dicht-ionisierende Strahlung zu evaluieren. Dafür wurden die Gewebeproben konventioneller Röntgenstrahlung sowie einem ausgedehnten 12C-Ionen Bragg-Peak ausgesetzt. Zur Bestrahlung der biologischen Proben mit 12C wurde mit dem GSI-eigenen Simulationsprogramm TRiP98 ein Tiefendosisprofil eines ausgedehnten Bragg-peaks erstellt. Ein weiteres Ziel dieser Arbeit war, dieses Tiefendosisprofil mit drei anderen Simulationsprogrammen (ATIMA, MCHIT, TRIM) zu reproduzieren und zu vergleichen. ATIMA und TRIM sind allgemeine Programme für den Energieverlust von Ionen in Materie. Sie können das von TRiP98 berechnetet Tiefendosisprofil nur ungenügend reproduzieren, da sie aufgrund fehlender Fragmentierung ein linear ansteigendes Tiefendosisprofil berechnen. Das Monte Carlo-Programm MCHIT, welches speziell für die Wechselwirkung von Ionen mit Materie in medizinischer Anwendung entwickelt wurde, zeigt die beste Übereinstimmung mit der TRiP98-Referenzkurve. Bis auf eine leicht höhere Durchschnittsdosis um 0.1 Gy konnte das Tiefendosisprofil nahezu exakt reproduziert werden. Die biologischen Proben bestanden aus Schnittkulturen gesunder Maus-Lebern und Explantatkulturen gesunder Maus-Pankreata, um Nebenwirkungen ionisierender Strahlen abzuschätzen. Zusätzlich wurde die Reaktion auf 12C-Bestrahlung in neoplastischem Lebergewebe transgener c-myc/TGF-α Mäuse mit induzierbarem Lebertumor bestimmt. Um eine mögliche Tageszeitabhängigkeit der Gewebereaktion auf die Bestrahlung zu untersuchen, wurden die Schnitt- und Explantatkulturen zu zwei unterschiedlichen Tageszeiten präpariert: zur Mitte des subjektiven Tages und zur Mitte der subjektiven Nacht. Die Präparate wurden für mehrere Tage auf einer Membran an einer Grenzschicht von Flüssigkeit und Luft kultiviert. Leber- und Pankreaskulturen gesunder C3H wildtyp Mäuse wurden mit einer Dosis von 2 Gy, 5 Gy oder 10 Gy Röntgenstrahlen bestrahlt. Leber- und Pankreaskulturen transgener Mäuse wurden mit ausgedehnten C-Ionen Bragg Peaks gleicher Dosen bestrahlt. Als Kontrolle dienten unbestrahlte Proben. Alle Proben wurden 1 h bzw. 24 h nach der Bestrahlung fixiert und immunhistochemisch auf Marker für Proliferation (Ki67), Apoptose (Caspase3) und DNA- Doppelstrangbrüche (γH2AX) untersucht. Während die Pankreas-Präparate im Hinblick auf die untersuchten Parameter leider keine auswertbaren Ergebnisse ergaben, zeigten die untersuchten Parameter im gesunden Lebergewebe deutliche Tag-Nacht Unterschiede: die Proliferationsrate war zur Mitte des subjektiven Tages signifikant höher als zur Mitte der subjektiven Nacht. Umgekehrt waren die Raten für DNA-Doppelstrangbrüche zur Mitte der subjektiven Nacht signifikant erhöht. Diese Tag-Nacht Unterschiede ließen sich in neoplastischem Lebergewebe nicht nachweisen. Unabhängig von der Art und Dosis, hatte die Bestrahlung im gesunden Lebergewebe keinen Einfluss auf die untersuchten Parameter. In neoplastischem Lebergewebe hingegen wird die Rate an DNA-Doppelstrangbrüchen durch eine Bestrahlung dosisabhängig erhöht. Die Auswirkungen ionisierender Strahlen auf das circadiane Uhrwerk wurden in Gewebeproben transgener Per2luc-Mäuse überprüft. Per2luc-Mäuse exprimieren das Enzym Luziferase unter der Kontrolle des Promoters von Per2, einem wichtigen Bestandteil des circadianen Uhrwerks. Daher erlaubt die Analyse dieser Tiere, den circadianen Rhythmus des molekularen Uhrwerks in Leber und anderen Geweben durch Messung der Luziferase-Aktivität in Echtzeit aufzuzeichnen. Wie in Leber- und Nebennierenkulturen dieser Tiere gezeigt werden konnte, führten ioniserende Strahlen dosisabhängig zu einem Phasenvorsprung des circadianen Uhrwerks. Die Ergebnisse erlauben die Schlussfolgerung, dass ionisierende Strahlen das circadiane Uhrwerk verstellen, Proliferation und Apoptose in gesundem Lebergewebe jedoch kaum beeinflussen