Kasper Kristensen
Technical University of Denmark
Publications 31
#1Grete E. Dinesen (DTU: Technical University of Denmark)H-Index: 13
#2Stefan Neuenfeldt (DTU: Technical University of Denmark)H-Index: 18
Last.Josianne Støttrup (DTU: Technical University of Denmark)H-Index: 23
view all 9 authors...
This study applied the Systems Approach Framework (SAF) to address the issue of declining Atlantic cod fishery in coastal areas. Interviews of 58 fishers from 26 harbours and meetings with national fisheries organisations and managers revealed the perception of an offshore movement of coastal cod. Numerical modelling based on fishing survey data did not substantiate these perceptions in the data-poor coastal waters. However, Data Storage Tag (DST) information combined with bottom sea water tempe...
1 CitationsSource
#1Mollie E. Brooks (DTU: Technical University of Denmark)H-Index: 7
#2Kasper Kristensen (DTU: Technical University of Denmark)H-Index: 14
Last.Benjamin M. Bolker (McMaster University)H-Index: 46
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Reproduction by individuals is typically recorded as count data (e.g., number of fledglings from a nest or inflorescences on a plant) and commonly modeled using Poisson or negative binomial distributions, which assume that variance is greater than or equal to the mean. However, distributions of reproductive effort are often underdispersed (i.e., variance < mean). When used in hypothesis tests, models that ignore underdispersion will be overly conservative and may fail to detect significant patte...
2 CitationsSource
#1Uffe Høgsbro Thygesen (DTU: Technical University of Denmark)H-Index: 3
#2Kasper Kristensen (DTU: Technical University of Denmark)H-Index: 14
Last.Jan E. Beyer (DTU: Technical University of Denmark)H-Index: 16
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#1Sofie Pødenphant (DTU: Technical University of Denmark)
#2Minh H. Truong (DTU: Technical University of Denmark)
Last.Per B. Brockhoff (DTU: Technical University of Denmark)H-Index: 31
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Abstract A novel possibility for easy and open source based analysis of sensory profile data by a formal multiplicative mixed model (mumm) with fixed product effects and random assessor effects is presented by means of the generic statistical R-package mumm. The package is using likelihood principles and is utilizing newer developments within Automatic Differentiation by means of the Template Model Builder R-package. We compare such formal likelihood based analysis with the Mixed Assessor Model ...
#1Margit EeroH-Index: 18
Last.Jonna TomkiewiczH-Index: 20
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Multiplicative mixed models can be applied in a wide range of scientific disciplines, since they are relevant in every situation where an interaction between a fixed effect and a random effect is present. Until now, no R package has been published, which can fit this type of models. The lack of user-friendly open source tools to fit these models, is the main reason that the models are not used as often as they could or should be. In this paper we introduce the user-friendly R package $\mathsf{mu...
#1Bradley M. Bell (UW: University of Washington)H-Index: 11
#2Kasper Kristensen (DTU: Technical University of Denmark)H-Index: 14
We consider the problem of computing derivatives of an objective that is defined using implicit functions; i.e., implicit variables are computed by solving equations that are often nonlinear and solved by an iterative process. If one were to apply Algorithmic Differentiation (AD) directly, one would differentiate the iterative process. In this paper we present the Newton step methods for computing derivatives of the objective. These methods make it easy to take advantage of sparsity, forward mod...
#1Cole C. Monnahan (UdeC: University of Concepción)H-Index: 9
#2Kasper Kristensen (DTU: Technical University of Denmark)H-Index: 14
Statistical inference is a widely-used, powerful tool for learning about natural processes in diverse fields. The statistical software platforms AD Model Builder (ADMB) and Template Model Builder (TMB) are particularly popular in the ecological literature, where they are typically used to perform frequentist inference of complex models. However, both lack capabilities for flexible and efficient Markov chain Monte Carlo (MCMC) integration. Recently, the no-U-turn sampler (NUTS) MCMC algorithm has...
1 CitationsSource
#2Kasper KristensenH-Index: 14
Last.Francois BastardieH-Index: 20
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Optimal and sustainable management of fish resources cannot be ensured without a thorough understanding of the migration patterns and population (demographic stock) structure. Recent studies suggest that these aspects of the economically and ecologically important deepwater hake Merluccius paradoxus are not reflected in the current assessment and management practices for the Benguela Current Large Marine Ecosystem. In this study, we compiled data from multiple demersal trawl surveys from the ent...
3 CitationsSource