Lars Relund NielsenLars Relund Nielsen
Department of Economics and Business Economics
Fuglesangs Allé 4
DK-8210 Aarhus V
Office 2621-114
Phone: +45 871 65145/+45 61 300 299 (mobile)
E-mail: lars@relund.dk
ORCID: 0000-0002-4802-3071

Cand.scient.oecon. (M.Sc.), Ph.D. 2004 in Mathematics and Economics at the University of Aarhus. Professor at Department of Economics and Business Economics, Business and Social Sciences, Aarhus University.

New publication

Research 19. December 2012

The research paper “Inventory control in a lost-sales setting with information about supply lead times” have been accepted for publication in International Journal of Production Economics.

We consider a periodically reviewed single-item inventory system in a lost sales setting where at most one order can be outstanding at a time and compare the performance of an inventory model assuming informed lead times to a model assuming uninformed independent and identically distributed lead times.

EURO 2012

Conference/meeting, Research 10. July 2012

This week I am participating in the EURO conference in Vilnius where I have a joint talk “Spare parts sharing with joint optimization of maintenance and inventory policies” with my college Christian Larsen.

VeRoLog 2012

Conference/meeting, Research 20. June 2012

The VeRoLog 2012 conference in Boglogna has just ended. I gave a talk about “Ranking shortest paths in Stochastic time-denpendent networks”. The conference had approximately 160 participants.

Det optimale udskiftningstidspunkt for en malkeko

Research 13. October 2010

En populærvidenskabelig artikel er netop udkommet i OrBit omkring min MDP model for udskiftning af malkekvæg.

Det optimale udskiftningstidspunkt for en malkeko“, L.R. Nielsen and E. Jørgensen, OrBit, 17, 14-16 (2010).

Quantifying walking and standing behaviour of dairy cows using a moving average based on output from an accelerometer

Research 19. August 2010

The research paper “Quantifying walking and standing behaviour of dairy cows using a moving average based on output from an accelerometer” have been accepted for publication in Applied Animal Behaviour Science. It presents research from my time at DJF where we use a moving average to predict walking and standing behaviour of dairy cows.

Converting a multidimensional index to a single unique id

R, Research 17. May 2010

I have written a small note about mapping a multidimensional index into a unique id. An unique id might be useful e.g. when having multiple state variables in an
Markov decision process. Here each state at a stage may be identified using the id.

New publications

Research 4. February 2010

Two of my papers have been accepted for publication. “Optimal Replacement Policies for Dairy Cows Based on Daily Yield Measurements” have been published in Journal of Dairy Scienc.

Abstract: Markov decision processes (MDP) with finite state and action space have often been used to model sequential decision making over time in dairy herds. However, the length of each stage has been at least 1 mo, resulting in models that do not support decisions on a daily basis. The present paper describes the first step of developing an MDP model that can be integrated into a modern herd management system. A hierarchical MDP was formulated for the dairy cow replacement problem with stage lengths of 1 d. It can be used to assist the farmer in replacement decisions on a daily basis and is based on daily milk yield measurements that are available in modern milking systems. Bayesian updating was used to predict the performance of each cow in the herd and economic decisions were based on the prediction. Moreover, parameters in the model were estimated using data records of the specific herd under consideration. This includes herd-specific lactation curves.

The other article “Embedding a state space model into a Markov decision process” have been accepted for publication in Annals of Operations Research.

Abstract: In agriculture Markov decision processes (MDPs) with finite state and action space are often used to model sequential decision making over time. For instance, states in the process represent possible levels of traits of the animal and transition probabilities are based on biological models estimated from data collected from the animal or herd. State space models (SSMs) are a general tool for modeling repeated measurements over time where the model parameters can evolve dynamically. In this paper we consider methods for embedding an SSM into an MDP with finite state and action space. Different ways of discretizing an SSM are discussed and methods for reducing the state space of the MDP are presented. An example from dairy production is given.

New position

Administration, Research 5. November 2009

CORAL

From the first of November 2009 I will be working as a Associate Professor at CORAL, Aarhus School of Business, University of Aarhus. I will be doing both research and teaching.

Koens økonomiske værdi

Research 28. October 2009

MalkemaskineI oktober nummeret af Ny Kvægforskning er der på side 8 en artikel om vores udskiftningsmodel baseret på daglige ydelsesmålinger.

How to replace cows optimally

Research, Teaching 19. October 2009

The 16th of October I gave a presentation to a group of students at KU Life about optimal replacement policies for dairy cows based on daily yield measurements. A hierarchical Markov decision process is used to solve the problem.

The following downloads are available: presentationhandouts (2×2) – animation 1 2 3

© Lars Relund Nielsen
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