Now showing items 22-41 of 130

    • Detection of environmental catastrophes 

      Järpe, Eric (University of Gothenburg, 2000-06-01)
      For on-line detection of environmental catastrophes spatial as well as temporal effects are crucial. Observations of some substance are made at different locations in space at discrete times. Mainly two spatial features ...
    • DETECTION OF GRADUAL CHANGES. STATISTICAL METHODS IN POST MARKETING SURVEILLANCE 

      Sveréus, Alecka (University of Gothenburg, 1995-02-01)
      Surveillance can be viewed as continual observation in time where the goal is to detect a change in the underlying process as soon as possible after it has occurred. In many applications, such as post marketing surveillance, ...
    • Detection of intra-uterine growth restriction 

      Petzold, Max; Sonesson, Christian; Bergman, Eva; Kieler, Helle (University of Gothenburg, 2003-03-01)
      A new methodology for on-line detection of intrauterine growth restriction (IUGR) is proposed where traditional methods for statistical surveillance are applied. Here, deficient growth rate is used to detect IUGR instead ...
    • Detection of turning points in business cycles 

      Andersson, Eva; Bock, David; Frisén, Marianne (University of Gothenburg, 2002-06-01)
      Methods for on-line monitoring of business cycles are compared with respect to the ability of early prediction of the next turn by an alarm for a turn in a leading index. Three likelihood based methods for turning point ...
    • Early warnings for turns in business cycles and finance 

      Bock, David (University of Gothenburg, 2003-06-01)
      In many areas, it is important to detect turning points in time series early and without faults. Turns in business cycles and financial time series are discussed here. A variety of approaches for analyzing the turns in ...
    • Effect of dependency in systems for multivariate surveillance. 

      Andersson, Eva (2007-11-22)
      In many situations we need a system for detecting changes early. Examples are early detection of disease outbreaks, of patients at risk and of financial instability. In influenza outbreaks, for example, we want to detect ...
    • Evaluation of multivariate surveillance 

      Frisén, Marianne; Andersson, Eva; Schiöler, Linus (2009-05-15)
      Multivariate surveillance is of interest in many areas such as industrial production, bioterrorism detection, spatial surveillance, and financial transaction strategies. Some of the suggested approaches to multivariate ...
    • Evaluation of some methods for statistical surveillance of an autoregressive process 

      Pettersson, Magnus (University of Gothenburg, 1998-04-01)
      Statistical surveillance is used for fast and secure detection of a critical event in a monitored process. This paper studies the performance for AR(l) processes. Two often suggested methods for detection of a shift in the ...
    • Evaluation of univariate surveillance procedures for some multivariate problems 

      Wessman, Peter (University of Gothenburg, 1996-04-01)
      The continual surveillance to detect changes has so far received large attention in the area of industrial quality control, where the monitoring of manufacturing processes to detect decreases in quality play an important ...
    • Evaluations of likelihood based surveillance of volatility 

      Bock, David (2007-12-13)
      The volatility of asset returns are important in finance. Different likelihood based methods of statistical surveillance for detecting a change in the variance are evaluated. The differences are how the partial likelihood ...
    • Evaluations of likelihood ratio methods for surveillance 

      Frisén, Marianne; Wessman, Peter (University of Gothenburg, 1996-03-01)
      Methods based on likelihood ratios are known to have several optimality properties. When control charts are used in practice, knowledge about several characteristics of the method is important for the judgement of which ...
    • Evaluations of likelihood ratio methods for surveillance. Differences and robustness. 

      Frisén, Marianne; Wessman, Peter (University of Gothenburg, 1998-02-01)
      In many areas there is a need for continual observation of a time series, with the goal of detecting an important change in the underlying process as soon as possible after it has occurred. In recent years there have been ...
    • Evaluations of some exponentially weighted moving average methods 

      Sonesson, Christian (University of Gothenburg, 2001-06-01)
      Several versions of the EWMA (Exponentially Weighted Moving Average) method for monitoring a process with the aim of detecting a shift in the mean are studied both for the onesided and the two-sided case. The effects of ...
    • EXACT PROPERTIES OF McNEMAR'S TEST IN SMALL SAMPLES 

      Jonsson, Robert (University of Gothenburg, 1993-02-01)
      The exact distribution of McNemar's test statistic is used to determine critical pOints for two-sided tests of equality of marginal proportions in the correlated 2x2 table. The result is a conservative unconditional test ...
    • Exact Semiparametric Inference About the Within-Subject Variability in 2 x 2 Crossover Trails. 

      Guilbaud, Olivier (University of Gothenburg, 1992-03-01)
      The comparison of primary interest in a 2 x 2 crossover trial typically concerns the effect of the treatments, say A and B, on the mean response level. This article deals with another important aspect, namely the within-subject ...
    • Explorative analysis of spatial aspects on the Swedish influenza data 

      Bock, David; Pettersson, Kjell (2007-12-20)
      The spatial aspects on the Swedish influenza data are analyzed. During the influenza period, reports on laboratory diagnosed cases and influenza-like-illness are obtained from viral and microbiological laboratories and ...
    • Explorative analysis of spatial patterns of influenza incidences in Sweden 1999—2008 

      Schiöler, Linus (2009-02-17)
      Information about the spatial spread of epidemics can be useful for many purposes. In this paper, the spatial aspect of Swedish influenza data is analyzed with the main aim of finding patterns that could be useful for ...
    • Graphical evaluation of statistical surveillance 

      Frisén, Marianne; Gottlow, Mattias (2003-10-01)
      A computer program which simultaneously gives graphical information on important characteristics of statistical surveillance methods is presented. Surveillance, that is continual observation of a time series with the goal ...
    • Hotelling´s T2 Method in Multivariate On-Line Surveillance. On the Delay of an Alarm 

      Andersson, Eva (2008-11-28)
      A system for detecting changes in an on-going process is needed in many situations. On-line monitoring (surveillance) is used in early detection of disease outbreaks, of patients at risk and of financial instability. By ...
    • HOUSEHOLD MARKET AND NON-MARKET ACTIVITIES - DESIGN ISSUES FOR A PILOT STUDY 

      Johnsson, Tommy (University of Gothenburg, 1982-02-01)
      The design of a pilot survey of households is the subject of this paper. A few methods to collect data about consumption expenditures and time-use are to be compared. Among the design issues are the allocation of the ...