Downscaling extremes: A comparison of extreme value distributions in point-source and gridded precipitation data

There is substantial empirical and climatological evidence that precipitation extremes have become more extreme during the twentieth century, and that this trend is likely to continue as global warming becomes more intense. However, understanding these issues is limited by a fundamental issue of spatial scaling: most evidence of past trends comes from rain gauge data, whereas trends into the future are produced by climate models, which rely on gridded aggregates. To study this further, we fit the Generalized Extreme Value (GEV) distribution to the right tail of the distribution of both rain gauge and gridded events. The results of this modeling exercise confirm that return values computed from rain gauge data are typically higher than those computed from gridded data; however, the size of the difference is somewhat surprising, with the rain gauge data exhibiting return values sometimes two or three times that of the gridded data. The main contribution of this paper is the development of a family of regression relationships between the two sets of return values that also take spatial variations into account. Based on these results, we now believe it is possible to project future changes in precipitation extremes at the point-location level based on results from climate models.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS287 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Spatio-temporal models for large-scale indicators of extreme weather

The changing global climate has sparked an interest in how these changes are affecting the intensity and frequency of extreme weather events such as thunderstorms and tornadoes because these extreme events pose a significant threat to life, property, and economic stability. This article uses and evaluates several spatio-temporal statistical extreme value models to model extreme weather from reanalysis data observed across the continental United States and Mexico. The models find that the intensity of extreme weather is particularly high for the central United States. Additionally, the intensity of extreme weather is increasing over time but the amount of increase may not be practically significant

Direct event location techniques based on Adams multistep methods for discontinuous ODEs

In this paper we consider numerical techniques to locate the event points of the differential system x′=f(x), where f is a discontinuous vector field along an event surface splitting the state space into two different regions R1 and R2 and f(x)=fi(x) when x∈Ri, for i=1,2 while f1(x)≠f2(x) when x∈Σ. Methods based on Adams multistep schemes which approach the event surface Σ from one side only and in a finite number of steps are proposed. Particularly, these techniques do not require the evaluation of the vector field f1 (respectively, f2) in the region R2 (respectively R1) and are based on the computation–at each step– of a new time ste

On tail trend detection: modeling relative risk

The climate change dispute is about changes over time of environmental characteristics (such as rainfall). Some people say that a possible change is not so much in the mean but rather in the extreme phenomena (that is, the average rainfall may not change much but heavy storms may become more or less frequent). The paper studies changes over time in the probability that some high threshold is exceeded. The model is such that the threshold does not need to be specified, the results hold for any high threshold. For simplicity a certain linear trend is studied depending on one real parameter. Estimation and testing procedures (is there a trend?) are developed. Simulation results are presented. The method is applied to trends in heavy rainfall at 18 gauging stations across Germany and The Netherlands. A tentative conclusion is that the trend seems to depend on whether or not a station is close to the sea.Comment: 38 page

A supplement to "Statistical modeling of extreme value behavior in North American tree-ring density series"

Other extreme value analyses In the article a block maxima modeling approach is employed. There are two other approaches that were considered: 1. The running-maxima approach. Instead of calculating one maxima for each block, the running maxima of block length B are calculated over the entire time period. While this approach generates more maximum values to study, it also introduces dependence between the maxima, and therefore necessitates a more involved model. 2. The points-over-threshold approach, which is also known as the peaks over thresholds approach, is based on examining all the observations over a given threshold. Under certain conditions, the distribution of excess values follow the generalized pareto distribution (GPD

A performance analysis of the club FC Bayern Munich in an international comparison on sporting and economic criteria

Die Bachelorarbeit beschäftigt sich mit einer Erfolgsanalyse des Vereins FC Bayern München im Vergleich mit den europäischen Spitzenmannschaften Real Madrid, FC Barcelona und Manchester United. Dabei werden sportliche und wirtschaftliche Erfolge der verschiedenen Vereine analysiert und diskutiert. Ziel der Arbeit ist es, die sportliche und wirtschaftliche Position des erfolgreichsten deutschen Fußballvereins im europäischen Vergleich anhand verschiedener Kriterien zu analysieren. Dabei werden besonders die einzelnen Einnahmequellen der Vereine untersucht und miteinander verglichen. Ebenso wird die gesamte finanzielle Situation der Vereine kritisch begutachtet.

3D Printed Prosthetic Arm with EMG Controls

Prosthetic technology has been advancing in the scientific community to the point where amputees are able to control the prosthetic in various ways. For example, one such method is to voltage signals from muscle contractions to trigger motors in the prosthetic to move the fingers of the hand. This project explores the practicality of this technique by building a 3D printed prosthetic arm installed with five individual servo motors. These motors are housed within the forearm, and are connected to an arduino, a microcontroller, that receives information from EMGs, or electromyography that are placed on various muscles on the subject’s body. As the subject flexes specific muscles, The EMG will record the electrical potential that the muscle is putting out. This signal then travels to the arduino which will then determine if the signal is of the correct value for a predetermined action. If it is then a signal is sent to the motors which in turn causes the hand to move, to grab, or pinch through predetermined actions which allow the patient to interact with various objects in their environment