The Shorth Plot

The shorth plot is a tool to investigate probability mass concentration. It is a graphical representation of the length of the shorth, the shortest interval covering a certain fraction of the distribution, localized by forcing the intervals considered to contain a given point x. It is easy to compute, avoids bandwidth selection problems and allows scanning for local as well as for global features of the probability distribution. We prove functional central limit theorems for the empirical shorth plot. The good rate of convergence of the empirical shorth plot makes it useful already for moderate sample size.Data analysis;distribution diagnostics;functional central limit theorem;probability mass concentration

OBDD-Based Representation of Interval Graphs

A graph $G = (V,E)$ can be described by the characteristic function of the edge set $\chi_E$ which maps a pair of binary encoded nodes to 1 iff the nodes are adjacent. Using \emph{Ordered Binary Decision Diagrams} (OBDDs) to store $\chi_E$ can lead to a (hopefully) compact representation. Given the OBDD as an input, symbolic/implicit OBDD-based graph algorithms can solve optimization problems by mainly using functional operations, e.g. quantification or binary synthesis. While the OBDD representation size can not be small in general, it can be provable small for special graph classes and then also lead to fast algorithms. In this paper, we show that the OBDD size of unit interval graphs is $O(\ | V \ | /\log \ | V \ |)$ and the OBDD size of interval graphs is $O(\ | V \ | \log \ | V \ |)$which both improve a known result from Nunkesser and Woelfel (2009). Furthermore, we can show that using our variable order and node labeling for interval graphs the worst-case OBDD size is$\Omega(\ | V \ | \log \ | V \ |)$. We use the structure of the adjacency matrices to prove these bounds. This method may be of independent interest and can be applied to other graph classes. We also develop a maximum matching algorithm on unit interval graphs using$O(\log \ | V \ |)$operations and a coloring algorithm for unit and general intervals graphs using$O(\log^2 \ | V \ |)$ operations and evaluate the algorithms empirically.Comment: 29 pages, accepted for 39th International Workshop on Graph-Theoretic Concepts 201

Extensible Statistical Software: On a Voyage to Oberon

Recent changes in software technology have opened new possibilitiesfor statistical computing. Conditions for creating efficient and reliableextensible systems have been largely improved by programming languages andsystems which provide dynamic loading and type-safety across module boundaries,even at run time. We introduce Voyager, an extensible data analysis systembased on Oberon, which tries to exploit some of these possibilities

The Excess Mass Approach and the Analysis of Multi-Modality

The excess mass approach is a general approach to statistical analysis. It can be used to formulate a probabilistic model for clustering and can be applied to the analysis of multi-modality. Intuitively, a mode is present where an excess of probability mass is concentrated. This intuitive idea can be formalized directly by means of the excess mass functional. There is no need for intervening steps like initial density estimation. The excess mass measures the local difference of a given distribution to a reference model, usually the uniform distribution. The excess mass defines a functional which can be estimated efficiently from the data and can be used to test for multi-modality

Testing Numerical Reliability of Data Analysis Systems

From 1990 to 1993, a series of tests on numerical reliability ofdata analysis systems has been carried out. The tests are based onL.Wilkinson's "Statistics Quiz". Systems under test included BMDP, Data Desk,Excel, GLIM, ISP, SAS, SPSS, S-PLUS,STATGRAPHICS. The results showconsiderable problems even in basic features of well-known systems. For allour test exercises, the computational solutions are well known. The omissionsand failures observed here give some suspicions of what happens in lesswell-understood problem areas of computational statistics. We cannot takeresults of data analysis systems at face value, but have to submit them to alarge amount of informed inspection. Quality awareness still needs improvement

Desenvolvimento de cultivos iniciadores para o processamento de embutidos cárneos artesanais.

Projeto/Plano de Ação: 03.03.02.33.00

Die Erschießung von acht "Meuterern" an Bord des Auswandererseglers Germania 1824: Bemerkungen zur offiziellen Dokumentation

The frigate GERMANIA set sail from Hamburg for Brazil in 1824. During the voyage, eight men were accused of mutiny and sentenced to death. Some of the passengers on the ship, which was under the command of Captain Hans Voss, were inmates of a prison in Hamburg whose voyage to Rio de Janeiro was the equivalent of a remission - only on condition, however, that they never return to the Hamburg region again. Apart from these prisoners there were emigrants on the ship, attracted by the promotional activities of the Brazilian agent Major Georg Anton Schäffer, who in 1822 had been commissioned by the Brazilian royal household to recruit people to come and settle in the country. Settlement of the country - which became independent that same year - was important to the Brazilian king Dom Pedro, son of the Portuguese king Juan VI, for several different reasons. One of his objectives was to have the immigrants chop down sections of jungle to create plantations, as well as to serve as soldiers in order to protect the royal family and fight in border conflicts. Major Georg Anton Schäffer, whose recruitment methods were notorious, had to move from Hamburg to Altona and then on to Bremen, because people feared an influx of vagabonds and paupers. German emigration to Brazil, largely caused by famines of the previous years, reached its high point of 30 percent in 1825. Those who decided to emigrate to Brazil were of differing origin: they included not only farmers, businessmen and tradesmen but also paupers and convicts. The negotiation transcript written on board the ship and other documents helping to reconstruct what took place on board the GERMANIA throw light on the events leading up to the execution of the eight accused mutineers, five of whom had boarded the vessel as convicts from Hamburg. The attempts to prevent them from arriving in Brazil began in Glückstadt, where the ship was supposed to be set on fire to this end. On the high seas, following an attempt to rebel against senior crew members, the death sentences were imposed and members of the ship's crew carried them out. The contents of the official negotiation transcript are doubtful, however, since the accused were forced to confess under torture and the main reason for the transcript was to make the plaintiffs' behaviour more officially acceptable. A letter received from a passenger who was also on board the GERMANIA, in which the brutality of the negotiators becomes clear, serves as a basis for a change of opinion with regard to the negotiation transcript

Keeping Statistics Alive in Documents

We identify some of the requirements for document integration of software components in statistical computing, and try to give a general idea how to cope with them in an implementation