Blar i NHH Brage på forfatter "Sandal, Leif Kristoffer"
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A new approach of fitting biomass dynamics models to real data based on a linear total allowable catch (TAC) rule : an optimal control approach
Ussif, Al-Amin M.; Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Discussion paper, Working paper, 2000-05)A non-traditional approach of fitting dynamic resource biomass models to data is developed in this paper. The adjoint technique is an optimal control or a variational method for parameter identification. It provides a novel ... -
On the dynamics of commercial fishing and parameter identification
Ussif, Al-Amin M.; Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Discussion paper, Working paper, 2000-05)This paper has two main objectives. The first is to develop dynamic models of commercial fisheries different from the existing models. The industry is assumed to have a well defined index of performance based on which it ... -
On the dynamics of commercial fishing and parameter identification
Ussif, Al-Amin M.; Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Working Paper, Working paper; Working paper, 2002-03)This paper has two main objectives. The first is to develop a dynamic model of commercial fisheries different from most existing models that assume optimizing behavior. The industry is assumed to have a well-defined index ... -
Optimal age-structured harvest in a dynamic model with heterogenous capital
Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Working Paper, Working paper, 2003-08)A dynamic optimization model with four state variables and two control variables is developed in order to analyze a fishery where on fleet-segment is targeting young fish and another fleet-segment is targeting older fish ... -
Optimal feedback controls : comparative evaluation of the cod fisheries in Denmark, Iceland and Norway
Arnason, Ragnar; Sandal, Leif Kristoffer; Steinshamn, Stein Ivar; Vestergaard, Niels (Working paper, Working paper; Working paper, 2000-01)The purpose of this paper is to compare the relative efficiency of the fish harvesting policies of Iceland, Norway and Denmark. We have chosen to concentrate on the cod fishery as this is the single most important fishery ... -
Optimal fishing policy for two species in a three-species predator-prey model: The case of capelin, cod and juvenile herring in the Barents Sea
Aanestad, Sigurd; Sandal, Leif Kristoffer; Eide, Arne (Discussion paper, Working paper, 2007-12)This paper presents a management model for the Barents Sea capelin and cod fisheries including juvenile herring in the biological model as the young herring influences the cod-capelin system. The objective of the study is ... -
Optimal management of renewable resources : a general feedback approach
Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Discussion paper, Working paper, 1998-09)Analytical solutions for optimal exploitation of renewable capital stocks are derived as feedback rules for a quite general optimization problem. By feedback rules is meant that optimal exploitation is given as an explicit ... -
Optimal population and capital dynamics in fisheries with irreversible investments
Sandal, Leif Kristoffer; Steinshamn, Stein Ivar; Hoff, Ayoe (Working paper, Working paper, 2007-06)A multi-dimensional, non-linear dynamic model in continuous time is presented for the purpose of finding the optimal combination of exploitation and capital investment in optimal renewable resource management. Non-malleability ... -
A perturbation approach on a class of optimal control problems, unifying the pontryagin and dynamic programming approach
Sandal, Leif Kristoffer; Berge, Gerhard (Discussion paper, Working paper, 2000-06)This article consider special ways of solving time dependent (non-autonomous) systems. Different types of time-dependent Optimal Control Problems in the setting of a Hamiltonian Formulation, are considered and the emphasis ... -
Pollution decay, consumer awareness and optimal carbon taxes
Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Discussion paper, Working paper, 2004-02)The effects of non-linear decay and consumer preferences are analyzed in a setting where optimal extraction of non-renewable resources is combined with stock externalities. The control is exercised via a corrective tax and ... -
Prediksjoner av vekt- og kvalitetsfordeling for slaktevolum i oppdrettsnæringen : en omfattende test av dyp læring og nevrale nettverk for prediktive formål i norsk akvakultur
Nygaard, Didrik; Vågen, Njål Slettebak (Master thesis, 2020)I denne oppgaven undersøker vi om nevrale nettverk kan forbedre prediksjon av vekt- og kvalitetsfordeling for slaktevolumet for matfisk, og hva følgene vil kunne være av en slik implementering. Nevrale nettverk benyttes ... -
The premium of marine protected areas : a simple valuation model
Kvamsdal, Sturla Furunes; Sandal, Leif Kristoffer (Working paper, Working paper, 2007-03)Marine Protected Areas are considered as a hedging tool against some of the uncertainties that trouble many fisheries today. Such tools are always connected with a cost; a premium. An optimal harvest rule is combined with ... -
The premium of marine protected areas : a simple valuation model
Kvamsdal, Sturla Furunes; Sandal, Leif Kristoffer (Discussion paper, Working paper, 2007-03)Marine Protected Areas are considered as a hedging tool against some of the uncertainties that trouble many fisheries today. Such tools are always connected with a cost; a premium. An optimal harvest rule is combined ... -
Probabilistic cost efficiency and bounded rationality in the newsvendor model
Ubøe, Jan; Andersson, Jonas; Jörnsten, Kurt; Lillestøl, Jostein; Sandal, Leif Kristoffer (Doctoral dissertation;41/14, Working paper, 2014-12)In this paper we establish a link between probabilistic cost efficiency and bounded rationality in the newsvendor model. This establishes a framework where bounded rationality can be examined rigorously by statistical ... -
Profit-driven planning and analysis of a WEEE recycling facility with a multi-period MILP model
Muyldermans, Louis; Quenon, Vallier (Master thesis, 2023)Electronic waste is one of the fastest-growing waste streams in the world. The challenges associated with the recycling of Waste Electrical and Electronic Equipment (WEEE) represent both threats, as the improper disposal ... -
Regional fisheries management on the high seas : the hit-and-run interloper model
McKelvey, Robert W.; Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Working Paper, Working paper; Working paper, 2002-08)The 1993 U.N. Straddling Stock Agreement prescribes a multi-national organizational structure for management of an exploited marine fish stock, one whose range straddles both "Extended Economic Zones" (EEZs) and high seas ... -
Settlement risk in cross-border transactions : traditional and new approaches
Polikarpova, Maria (Master thesis, 2018)Although the wholesale payment systems operate unnoticed daily, these arrangements are crucial for our daily life. In this thesis I attempt to shed more light on the settlement risk in traditional wholesale payment systems ... -
A simple approach to global optimal feedback solutions : with emphasize on certain management problems in economics
Sandal, Leif Kristoffer; Berge, Gerhard (Discussion paper, Working paper, 2001-06)Dynamic optimization problems covers a great class of problems in management science and technology. The classical problem formulations being the variational approach as in classical mechanics, like Hamilton's principle ... -
A simplified feedback approach to optimal resource management
Sandal, Leif Kristoffer; Steinshamn, Stein Ivar (Working Paper, Working paper, 2001-09)Optimal exploitation of a renewable capital stock is derived as a feedback rule for a general dynamic optimisation problem with a single resource. By a feedback rule is meant that optimal exploitation is given as an explicit ... -
Stackelberg equilibria in a multiperiod vertical contracting model with uncertain and price-dependent demand
Sandal, Leif Kristoffer; Ubøe, Jan (Discussion paper;2012:2, Working paper, 2012-02)In this paper, we consider Stackelberg games in a multiperiod vertical contracting model with uncertain demand. Demand has a distribution with a mean and variance that depend on the current retail price, and this ...