Estimating the maximum possible earthquake magnitude using extreme value methodology: the Groningen case

The area-characteristic, maximum possible earthquake magnitude $T_M$ is required by the earthquake engineering community, disaster management agencies and the insurance industry. The Gutenberg-Richter law predicts that earthquake magnitudes $M$ follow a truncated exponential distribution. In the geophysical literature several estimation procedures were proposed, see for instance Kijko and Singh (Acta Geophys., 2011) and the references therein. Estimation of $T_M$ is of course an extreme value problem to which the classical methods for endpoint estimation could be applied. We argue that recent methods on truncated tails at high levels (Beirlant et al., Extremes, 2016; Electron. J. Stat., 2017) constitute a more appropriate setting for this estimation problem. We present upper confidence bounds to quantify uncertainty of the point estimates. We also compare methods from the extreme value and geophysical literature through simulations. Finally, the different methods are applied to the magnitude data for the earthquakes induced by gas extraction in the Groningen province of the Netherlands

Simple verification of completeness of two addition formulas on twisted Edwards curves

Daniel Bernstein and Tanja Lange  proved thattwo given addition formulas on twisted Edwards elliptic curvesax^2 + y^2 = 1 + dxy are complete (i.e. the sum of any two pointson a curve can be computed using one of these formulas). Inthis paper we give other simple verification of completenessof these formulas using for example Groebner bases and an ¨algorithm implemented in Magma, which is based on the fact thatcompleteness means that some systems of polynomial equationshave no solutions. This method may be also applied to verifycompleteness  of additions formulas on other models of ellipticcurves

„Projektowanie włączające” – proces projektowania nowoczesnych technologii z aktywnym udziałem adresatów rozwiązań

Projekt finansowany ze środków Narodowego Centrum Badań i Rozwoju w ramach programu „Innowacje społeczne”. Doniesienie z etapu badań „System elektronicznego wspomagania samodzielności życiowej osób z niepełnosprawnością intelektualną”

Arithmetic using compression on elliptic curves in Huff's form and its applications

In this paper for elliptic curves provided by Huff's equation $H_{a,b}: ax(y^2-1) = by(x^2-1)$ and general Huff's equation $G_{\overline{a},\overline{b}}\ :\ {\overline{x}}(\overline{a}{\overline{y}}^2-1)={\overline{y}}(\overline{b}{\overline{x}}^2-1)$ and degree 2 compression function $f(x,y) = xy$ on these curves, herein we provide formulas for doubling and differential addition after compression, which for Huff's curves are as efficient as Montgomery's formulas for Montgomery's curves $By^2 = x^3 + Ax^2 + x$. For these curves we also provided point recovery formulas after compression, which for a point $P$ on these curves allows to compute $[n]f(P)$ after compression using the Montgomery ladder algorithm, and then recover $[n]P$. Using formulas of Moody and Shumow for computing odd degree isogenies on general Huff's curves, we have also provide formulas for computing odd degree isogenies after compression for these curves.Moreover, it is shown herein how to apply obtained formulas using compression to the ECM algorithm. In the appendix, we present examples of Huff's curves convenient for the isogeny-based cryptography, where compression can be used

Intégration des impacts sur la santé des travailleurs dus aux expositions professionnelles aux polluants à l’analyse du cycle de vie

RÉSUMÉ : La santé humaine est l’un des grands enjeux de l’analyse du cycle de vie (ACV). Les impacts sur la santé humaine prennent en compte principalement l’exposition aux polluants émis dans l’environnement tout au long du cycle de vie du produit. Au cours des dix dernières années, plusieurs travaux de recherche ont montré l’importance des impacts des conditions de travail sur la santé des travailleurs mais les grandes méthodes ACV et les études ACV ne prennent pas cette problématique en compte. Les principales méthodes existantes pour évaluer l’impact sur la santé des travailleurs reposent soit sur l’analyse des statistiques d’accidents et de maladies professionnelles, soit sur des modèles d’exposition aux polluants en milieu de travail. Il n’existe pas de méthode spécifique aux expositions aux polluants en milieu de travail qui repose sur un modèle de cause à effet et qui permette d’avoir une analyse à l’échelle d’un cycle de vie. Cette thèse présente une revue de la littérature existante traitant de l’intégration de la santé et sécurité au travail en ACV. Une méthode est ensuite proposée pour modéliser l’impact potentiel sur les travailleurs d’un secteur industriel lié à l’exposition à l’inhalation de substances chimiques en milieu de travail, en combinant les concentrations d’exposition au temps de travail nécessaire dans ce secteur par unité fonctionnelle. Elle repose sur l’utilisation de données publiques de concentrations de polluants en milieu de travail et sur la chaîne de cause à effet recommandée en ACV via l’utilisation des facteurs d’effet de USEtox. Les facteurs de caractérisation (FC) pour l’ensemble des secteurs industriels de l’économie des États-Unis sont fournis avec des intervalles de confiance, permettant ainsi de calculer un impact potentiel de l’exposition des travailleurs aux polluants organiques par heure travaillée. Une seconde méthode est ensuite présentée, permettant d’étendre l’utilisation des FC fournis par la première méthode à l’échelle d’une chaîne de valeur via l’utilisation d’un modèle économique input output. Les FC permettant de calculer l’impact potentiel sur les travailleurs de l’exposition aux polluants organiques sur l’ensemble de la chaîne de valeur sont fournis par dollar de production de chaque secteur de l’économie. Finalement, des FC mis à jour sont fournis afin de prendre en compte les données les plus récentes ainsi que les polluants inorganiques et matières particulaires.----------ABSTRACT : Human health is one of the main foci of life cycle assessment (LCA). Impacts on human health are primarily modelled based on outdoor emissions of pollutants from all life cycle stages and subsequent human exposure. In the past decade, various scientific publications have pointed out the importance of including work environment in LCA but this has not yet lead to a formal inclusion. Existing methods focusing on work environments in an LCA are built upon either occupational injury and illnesses statistics or occupational chemical exposures models. This thesis addresses the need for a method that simultaneously makes use of a cause to effect model for chemical exposure and provides a life cycle perspective. The thesis includes a literature review focusing on LCA and the working environment. A method is then developed with a focus on occupational exposure to organic chemicals. This method relies upon a measured occupational chemical concentration database; it models the potential impacts combining the concentrations with effect factors from the USEtox model and the number of hours of work per functional unit. Characterization factors (CF) are provided for all manufacturing sectors of the United States economy with confidence intervals. The CFs correspond to potential impact per hour worked in each industrial sector of the economy. A second method is proposed, extending the first method to model entire value chains through the use of an input output economic model. Corresponding CF represent the potential impact on worker health of occupational exposures to organic chemicals by inhalation in the entire value chain per dollar of value of an economic sector output. Finally, the CF are updated using the most up-to date data and expanded to also assess inorganic chemicals and particulate matter

Guest Editorial: Special Issue on “Lithosphere Dynamics and Earthquake Hazard Forecasting”

Brilliant scientific ideas coupled with quantitative modelling and laboratory experiments have determined progress in seismology and geodynamics for the last several decades. Methods of nonlinear geophysics, inverse problems, mathematical statistics, extreme theory and data analysis have improved knowledge of the structure of the Earth’s lithosphere, earthquake generation, predictability, and seismic hazards. This Special Issue of Surveys in Geophysics “Lithosphere Dynamics and Earthquake Hazard Forecasting” is dedicated to the 100th anniversary of the birth of Professor Vladimir (Volodya) Keilis-Borok (1921–2013), a distinguished mathematical geophysicist. For more than 60 years, the topics of seismology, nonlinear dynamics of the lithosphere, and earthquake prediction were central in Keilis-Borok's research.Open Access funding enabled and organized by Projekt DEAL.https://www.springer.com/journal/10712hj2022Geolog

Truizmy Jenny Holzer jako kontrhegemoniczna praktyka artystyczna

Celem artykułu jest interpretacja strategii artystycznych wykorzystanych przez amerykańską artystkę neokonceptualną Jenny Holzer w pracy Truizmy w kontekście agonistycznej koncepcji polityki Chantal Mouffe. Powstały pod koniec lat 70. XX wieku ciąg wzajemnie wykluczających się znaczeniowo jednowersówek, pozbawionych autora, multiplikowany w różnorodnych formach i obszarach życia codziennego – od przedmiotów jednorazowego użytku, takich jak długopisy czy prezerwatywy, aż po tablice świetlne na Times Square – staje się doskonałą metonimią tego, co można nazwać wiedzą potoczną. Powielając pracę w różnorodnych formach i kontekstach od końcówki lat 70. XX wieku aż do dziś, Holzer obnaża sposoby uprawomocniania się przestrzeni dyskursywnych, próbując włączyć do niej swój własny język

Estimation of earthquake hazard parameters from incomplete data files. Part III. Incorporation of uncertainty of earthquake-occurrence model

Most probabilistic seismic-hazard analysis procedures require that at least three seismic source parameters be known, namely the mean seismic activity rate λ, the Gutenberg–Richter b-value, and the area-characteristic (seismogenic source) maximum possible earthquake magnitudemmax. In almost all currently used seismic-hazard assessment procedures that utilize these three parameters, it is explicitly assumed that all three remain constant over time and space. However, closer examination of most earthquake catalogs has indicated that significant spatial and temporal variations existed in the seismic activity rate λ, as well as in the Gutenberg–Richter b-value. In this study, the maximum likelihood estimation of these earthquake hazard parameters considers the incompleteness of the catalogs, the uncertainty in the earthquake magnitude determination, as well as the uncertainty associated with the applied earthquake-occurrence models. The uncertainty in the earthquake-occurrence models is introduced by assuming that both the mean seismic activity rate λ and the Gutenberg–Richter b-value are random variables, each described by the gamma distribution. This approach results in the extension of the classic frequency–magnitude Gutenberg–Richter relation and the Poisson distribution of the number of earthquakes with their compounded counterparts (Benjamin, 1968; Campbell, 1982, 1983). The proposed procedure was applied in the estimation of the seismicity parameters in an area that had experienced the strongest and most devastating earthquake in contemporary South African history, namely the 29 September 1969 Mw 6.3 Ceres–Tulbagh event. In this example, it was shown that the introduction of uncertainty in the earthquake-occurrence model reduced the mean return periods, leading to an increase of the estimated seismic hazard. Additionally, this study confirmed that accounting for magnitude uncertainties had the opposite effect, that is, it brought about increases in the return periods, or, equivalently, a reduction of the estimated seismic hazard.The National Research Foundation of South Africa (Grant Numbers 76906 and 94808).http://www.seismosoc.orgpublications/bssa/am2016Geolog

Preliminary investigation into the cause of acid mine water induced seismicity in Johannesburg

A preliminary investigation was done into the possible causes of the increased seismic activity in the Witwatersrand Basin. The paper focuses on approximated underground mining areas, groundwater mobility, rock types and the proximity of fault lines to seismic events. These parameters were mapped and correlated with observed seismicity in the area. There is some indication that the presence of underground mining areas has a positive relationship with the occurrence of seismic events. The other parameters exhibit a negative relationship with seismic activity. However, more detailed investigations are required before final conclusions can be drawn. An approach to risk assessment of possible earthquake scenarios in the City of Johannesburg (CoJ) is proposed. The approach aims to assess potential damage to infrastructure and loss of life in the case of an earthquake. The results of such an assessment may provide justification for more detailed investigations