| 1. |
- Oksanen, Lauri, et al.
(author)
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Islands as tests of the green world hypothesis.
- 2010
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In: Trophic Cascades – Predators, Prey, and the changing dynamics of Nature. - Washihgton DC : Island Press. - 9781597264860 ; , s. 163-178, s. 163-178
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Book chapter (other academic/artistic)
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| 2. |
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| 3. |
- Belyaev, Yuri K
(author)
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Assessing accuracy of statistical inferences by resamplings
- 2010
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In: Mathematical and Statistical Models and Methods in Reliability. - New York : Birkhäuser Verlag. - 9780817649708 - 9780817649715 ; , s. 193-206
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Conference paper (other academic/artistic)abstract
- Suppose that a list of explanatory variables and corresponding random responses was obtained during a series of regression experiments. The characteristic of interest is the mean value of responses considered as a regression function of corresponding values of explanatory variables. For example, if responses are failure times of tested elements, then the conditional mean value of life time given the value of explanatory variable is one of the important reliability characteristics of the tested elements. The analysis of this type of data can be realized in the framework of linear heteroscedastic regression models. Here, one of the central problems is a consistent estimation of the unknown regression function when the size of data grows unboundedly. The problems related to analysis of regression data attracted many researches, see Wu [Ann. Statist. 14, 1261–1350 (1986)]. We give an approach to consistent solution of the problems under the assumption that values of explanatory variables are real numbers and the regression function is a polynomial with unknown degree and coefficients. The selection of regression function is based on resamplings from terms in the sum of the residuals estimated by the ordinary least squares method with various values of polynomial degree. In a similar way, resamplings from the weighted estimated residuals are used for consistent estimation of the deviations distributions of estimated coefficients from their true unknown values. The consistency of applied resamplings methods holds under certain assumptions, e.g. it is assumed that the residuals distributions have uniformly integrable second moments (assumption AW 2). Given in Appendix a variant of the Central Limit Resampling Theorem is used in the proofs of Theorems 1 and 2.
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| 4. |
- Cronie, Ottmar, et al.
(author)
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Maximum likelihood estimation in a discretely observed immigration-death process
- 2010
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Reports (other academic/artistic)abstract
- In order to find the maximum likelihood (ML) estimator of the parameter pair governing the immigration-death process (a continuous time Markov chain) we derive its transition probabilities. The likelihood maximisation problem is reduced from two dimensions to one dimension. We also show the consistency and the asymptotic normality of the ML-estimator under an equidistant sampling scheme, given that the parameter pair lies in some compact subset of the positive part of the real plane. We thereafter evaluate, numerically, the behaviour of the estimator and we finally see how our ML-estimation can be applied to the so-called Renshaw-Särkkä growth interaction model; a spatio-temporal point process with time dependent interacting marks in which the immigration-death process controls the arrivals of new marked points as well as their potential life-times.
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| 5. |
- Cronie, Ottmar, et al.
(author)
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Spatio-Temporal Modelling of Swedish Scots Pine Stands
- 2011
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Reports (other academic/artistic)abstract
- Considering measurements of locations and radii at breast height made at three different time points of the individual trees in ten Swedish Scots pine plots, we employ the so called growth-interaction (GI) process for the spatio-temporal modelling of the plots. The GI-process places trees at random locations in the study region and assigns radii (sizes) to the trees, which interact and grow with time. It has been used to model Scots pine plots in previous studies, and to improve the fit we suggest some modifications of the model: A different location assignment strategy and a different function for the open-growth (growth in absence of competition). We believe also that the space-time data contain too small trees to reflect the open-growth properly, which primarily affectsthe carrying capacity parameter. We evaluate the open-growth froma separate set of data which consists of size and age measurements ofolder and larger single Scots pines. This data set better represents the open-growth of Scots pines than the space-time data sets. A linear relationship is found between the estimated site indexes of the plots and the sizes, and this relationship is exploited in the estimation of the carrying capacity. For each of the ten space-time data sets (plots) we estimate the remaining parameters of the GI-process and finally, by means of some Monte Carlo tests, we test the goodness-of-fit of simulated predictions from the fitted model.
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| 6. |
- Jiang, Xuemei, et al.
(author)
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Impacts of policy measures on the development of state-owned forests in Northeast China : Theoretical results and empirical evidence
- 2011
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Reports (other academic/artistic)abstract
- State-owned forest enterprises (SOFEs) in northeast China and Inner Mongolia play important roles both in timber production and in the maintenance of ecological security. However, since the late 1970s, forest resource and economic crises have seriously restricted these functions. Based on a theoretical and an empirical analysis of the harvest and investment behavior of the SOFEs, we examined the effects of forest policies and the socioeconomic conditions on the behavioral choices of the SOFEs. Both the extent to which SOFE supervising authorities emphasized improvement of forest resources in their annual evaluations and the increases in expenses necessary to manage SOFEs had significant impacts on harvest and investment decisions as well as development of forest resources. Promoting the management and utilization of non-timber resources, as well as reforms to increase the efficiency of forest protection and management, have reduced timber harvests as intended, which in turn has increased investment and improved forest resources. The effects have been relatively small, however. In contrast, reforms aimed at timber harvest and afforestation activities actually contributed toincreasing the timber harvest, which affected the development of the forest resources negatively.
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| 7. |
- Johansson, Per-Olov, et al.
(author)
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The New Economics of Evaluating Water Projects
- 2011
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In: Annual Review of Resource Economics, Vol 3. - : Annual Reviews. - 1941-1359 .- 1941-1340. - 9780824347031 ; , s. 231-254
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Book chapter (other academic/artistic)abstract
- We review key developments in the cost-benefit analysis of water projects, including conceptual and empirical issues. We emphasize general equilibrium and dynamics, in particular the links between economic and ecological systems.
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| 8. |
- Keskitalo, E. Carina H., 1974-, et al.
(author)
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Climate change mitigation and adaptation in Swedish forests : promoting forestry, capturing carbon and fuelling transports
- 2011
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In: Energy, policy, and the environment. - New York : Springer. - 9781461403494 - 9781461403500 ; , s. 133-153
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Book chapter (other academic/artistic)abstract
- Sweden is a land of forests. In fact, almost 60% of the surface area is covered by forest (both productive and nonproductive). Since the end of the nineteenth century, these woodlands have primarily been utilized by the forest industry but reindeer husbandry in the north and tourism and recreation, including hunting, berry picking, and other local, customary activities also exploit the forest landscape. Ownership is highly diversified. Of the estimated 23 million hectares of productive forest land, some 40% is owned by large forest companies and the government and approximately 50% by some 350,000 small, nonindustrial, private owners.
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| 9. |
- Yu, Jun, 1962-, et al.
(author)
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Distribution Estimation for Fishing Time
- 2011
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Reports (other academic/artistic)abstract
- Information on visitation frequencies in recreational fishing is important when dealing with fishing tourism in order to make prognoses forthe future upon changes in the management of the aquatic environment (flow regime or habitat restoration), fishing regulations, or to estimatethe total harvest of fish. Therefore interviews have been performed in a number of streams and sections of streams, throughout the last twenty years in the Jämtland-Härjedalen region in Sweden. In this work the probability distribution of total fishing hours a day (possibly on differentperiods) is considered. We found that both Gamma and Weibull distributions can be considered as approximate distributions that generate the data. Gamma distribution fits very well for summer season while Weibull distribution is more appropriate for the other periods. In general, the gamma model is easier to interpret and better fits the mode of the distribution, and therefore, is preferred. Having parameters estimated, we are able to calculate probabilities of different fishing times. It is also suggested to use two periods: mid-summer – the end of August and other dates. The modelling at section level seems to be successful. Both the Gamma and Weibull distributions fits well the data for all periods, providing that the number of observations are not less than 20. The mean fishing hours, however, varies from section to section, even within the same watercourse.
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| 10. |
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