Sökning: "stochastic growth rate"

Visar resultat 1 - 5 av 37 avhandlingar innehållade orden stochastic growth rate.

1. 1. The dynamics in harvested populations

   Författare :Anders Wikström; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fluctuations; temporal; state-space; Harvest; cod; vendace; elasticity; stage-structured; stochastic; growth-rate; Baltic Sea; Bothnian Bay;

   Sammanfattning : We are interested in the effect of harvesting on population fluctuations and for that purpose we develop and analyze an age-structured model where recruitment is a stochastic process and the adult segment of the population is harvested. When a constant annual harvest is taken the coefficient of variation of the adult population increases for most parameter values due to the age truncation effect, i. LÄS MER

3. 2. Metal film growth on weakly-interacting substrates : Stochastic simulations and analytical modelling

   Författare :Víctor Gervilla Palomar; Kostas Sarakinos; Georgios Almyras; Pär Olsson; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Thin films are nanoscale layers of material, with exotic properties useful in diverse areas, ranging from biomedicine to nanoelectronics and surface protection. Film properties are not only determined by their chemical composition, but also by their microstructure and roughness, features that depend crucially on the growth process due to the inherent out-of equilibrium nature of the film deposition techniques. LÄS MER

4. 3. Modelling and Inference for Spatio-Temporal Marked Point Processes

   Författare :Ottmar Cronie; Göteborgs universitet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Asymptotic normality; Consistency; Cox-Ingersoll-Ross process; Diffusion process; Edge correction; Goodness-of-fit; Richards growth function; Growth-interaction process; Immigration-death process; Least squares estimation; Markov process; Maximum likelihood estimation; Open-growth; Spatio-temporal marked point process; Stationarity; Stochastic differential equation; Transition density; Asymptotic normality;

   Sammanfattning : This thesis deals with inference problems related to the growth-interaction process (GI-process). The GI-process is a continuous time spatio-temporal point process with dynamic interacting marks (closed disks), in which the immigration-death process (ID-process) controls the arrivals of new marked points as well as their potential life-times. LÄS MER

5. 4. Population viability analysis for plants : practical recommendations and applications

   Författare :Satu Ramula; Kari Lehtilä; Patrik Dinnétz; Esa Ranta; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; demography; matrix population models; population viability analysis; population growth rate; stochastic models; Biology; Biologi;

   Sammanfattning : Population viability analysis (PVA) is commonly used in conservation biology to predict population viability in terms of population growth rate and risk of extinction. However, large data requirements limit the use of PVA for many rare and threatened species. LÄS MER

7. 5. Stochastic epidemics on random networks and competition in growth

   Författare :Carolina Fransson; Pieter Trapman; Daniel Ahlberg; Julia Komjathy; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; random graphs; branching processes; SIR epidemics; malthusian parameter; urn model; matematisk statistik; Mathematical Statistics;

   Sammanfattning : The COVID-19 pandemic has dramatically demonstrated the importance of epidemic models in understanding and predicting disease spread and in assessing the effectiveness of interventions. The overarching topic of this thesis is stochastic epidemic modelling, with the main focus on the role of the underlying social structure in infectious disease spread. LÄS MER