Suchergebnisse

Samenvatting.De afstandsmethode voor het schatten van een dichtheid, bijv. het stamtal per ha in bossen, werd voorgesteld en uitgewerkt door F. E. Essed [1], Men zou deze ook kunnen interpreteren ah een "wachttijdmethode" ter bepaling van de frequentie per tijdseenheid van een (in de tijd) poisson verdeelde gebeurtenis als het binnenkomen van gesprekken op een telefooncentrale. In dit artikel wordt de methode verder ontwikkeld, waarbij een toepassing, nl. het tellen van slakken (van de soort Galba trunculata, gastheer van de leverbot) in greppels ‐dit als onderdeel van een onderzoek naar de biologie van de leverbot ‐, nader wordt beschreven (par. 2).Na definities (par 1.0) (in bosbouwkundige termen) van achtereenvolgens: een bos, een toevallig bos, een (homogeen) poisson‐bos een locaalpoisson‐bos, worden enige nieuwe schatters gedefinieerd ((1) en (2) in par. 1.1.), en hun eigenschappen voor een homogeen poisson‐bos besproken. Voor een locaal poisson‐bos wordt een afzonderlijke schatter besproken (par. 1.2). In par. 1.3 wordt een homogeniteits‐toets besproken, alsook een dichtheidsschatter, die al naar de omstandigheden een telling van bomen of een afstandsmeting is.In par. 1 worden de statistische technieken met enkele hulptabellen besproken. Par. 2 beschrijft het ontwikkelen van een veldmethode voor het tellen van slakken bij het leverbotonderzoek. Par. 3 geeft de wiskundige achtergrond voor de methoden beschreven in par. 1.

Volunteer-based biodiversity monitoring schemes are currently developed and tested for feasibility in and for agricultural landscapes in Germany. For the assessment of the effectiveness and efficiency of volunteer-based biodiversity monitoring schemes, indicators are required but so far, such indicators have neither been developed nor tested. Here, sets of indicators are developed and presented based on evidence from scientific literature and from the volunteers' perspectives. As a starting point of the development of indicators, challenges for volunteers need to be identified that may hinder them from taking part in the schemes and from achieving project goals. On the basis of formulated actions to overcome these challenges, three sets of indicators are derived, covering the areas of i) capacity building for volunteer-based engagement, (ii) appreciation and valuing of volunteer commitment, and (iii) education and learning in volunteer-based approaches. Indicators are developed to potentially serve internal and external communication and act as project quality assurance measures. At the same time, the presented indicators may potentially also be applied by decision-makers in policy as well as by funding agencies. In a next step, indicators are co-developed using participatory evaluation approaches to combine conventionally developed indicators with indicators developed with members of the community of practitioners. Implementing indicators in practice as well as regular reflections and revisions will ensure an adaptive quality assurance system for volunteer-based biodiversity monitoring and beyond.

This manuscript sets out a process for estimating fatalities in collapsed buildings due to ground shaking in an earthquake. The aim of this research is to supplement current earthquake loss estimation with fatality rates (percentage of occupants killed) for use in models which are based on recent empirical information on deaths from earthquakes. This document specifically explores the lethality potential to occupants of collapsed structures. Whilst earthquake casualty modeling has admittedly suffered from a lack of post-earthquake collection of data and rigour in assessing these data, recent earthquakes such as 2008 Wenchuan (China) and 2011 Christchurch (New Zealand) have brought to light some important findings. Under the auspices of US Geological Survey's PAGER, empirical fatality data related to collapses of buildings from significant earthquakes in the past 40 years have been thoroughly examined. Through detailed investigations of fatal building collapses and the volume reductions within these buildings, important clues related to the lethality potential of different failure mechanisms of global modern and older construction types were found. The gathered evidence forms the basis of the derivation of a set of fatality rates for use in loss models. The set of judgment-based rates are for 31 global building types. This significant advancement in casualty modeling, the resolutions and quality of available data, the important assumptions made, and the final derivation of fatality rates are discussed here. This document contributes to global efforts to develop a way of estimating probable earthquake fatalities very rapidly after an earthquake has taken place. The fatality rates proposed here can be incorporated directly into earthquake loss estimation models where fatalities are derived from collapses of different types of buildings

A stationary sequence of nonnegative random variables generated by autoregressive (AR) models may be used to describe the inter‐arrival times between events in counting processes. Even though, several such models are available in the literature, there is no unified approach to estimate their parameters. In this paper, we propose a class of combined estimating function method to estimate the model parameters of AR models with gamma marginals. The proposed method is compared with other estimation procedures and are illustrated by simulation and data analysis.

Following in the wake of R. W. Taylor's The Problems with Social Indicators in the Australian Journal of Social Issues, this article defends the use of indicators as practical policy tools. It argues that, in assessing the use of indicators, researchers should differentiate more clearly between 'ideal' indicators and 'existing' indicators, and between inadequacies within the indicator and subjective interpretations by the user.

One method of short-term economic forecasting is the use of indicators which normally change direction in advance of business activity as a whole. This method has been extensively developed over many years, with some success, by the National Bureau of Economic Research in the United States. In the present article we have explored the possibility of finding such a set of leading indicators for the British economy, with special reference to post-war movements.

In random digit dial (RDD) telephone surveys, some telephone numbers cannot be definitively determined to be residential or nonresidential even after many call attempts. Estimating residency rates for these undetermined telephone numbers is important because the residency rate is needed to compute the response rate accurately. This article reviews methods used previously to estimate the residency rate for undetermined telephone numbers & discusses some of the problems with these methods. A new approach using survival analysis methods is introduced that uses data on the number of call attempts to the telephone numbers. The approach is extended to include other auxiliary data known about the sampled telephone numbers, such as whether they are listed. The survival function method is then applied to two large RDD surveys & the estimates are compared to estimates using other methods. Limitations & precautions for the survival function method are discussed. 3 Tables, 2 Figures, 11 References. Adapted from the source document.