Papers by Halvard Arntzen
EURO Journal on Transportation and Logistics, Dec 1, 2017
Building on the work of Gendreau et al. (Eur J Oper Res 88(1):3-12; 1996), we review the past 20 ... more Building on the work of Gendreau et al. (Eur J Oper Res 88(1):3-12; 1996), we review the past 20 years of scientific literature on stochastic vehicle routing problems. The numerous variants of the problem that have been studied in the literature are described and categorized.
Mathematics for Applications, Dec 22, 2022
Based on an assumption of an existing scoring probability difference between two teams engaged in... more Based on an assumption of an existing scoring probability difference between two teams engaged in a football match, the conditional probability distribution given the number of goals in the match for the low quality team beating the high quality team, is derived. Furthermore, similar distributions for the high quality team beating the low quality team as well as a draw are also derived. Based on a Poisson distribution of goals, we discuss a potential for optimizing expected uncertainty of outcome (UO) by adjusting intra-match rules or league rules for team sports. The main variables in this regard are (i) the typical number of goals scored, and (ii) the evenness of competing teams. We identify a curve defining the optimal expected number of goals as a function of team quality difference.
Anvendt informatikk: eNytt, Juni 2008
Opptrykk av studentarbeider i informatikk ved Høgskolen i Molde, Avdeling for økonomi, informatik... more Opptrykk av studentarbeider i informatikk ved Høgskolen i Molde, Avdeling for økonomi, informatikk og samfunnsfag.Denn utgaven av Anvendt informatikk : eNytt inneholder fire utvalgte prosjekter ved avdeling for økonomi, informatikk og samfunnsfag i vårsemesteret 2008. Rapportene som er presentert kan være noe forkortet i forhold til originalarbeidene, men de er ellers ikke redigert eller modifisert av redaksjonen eller andre
Journal of Heuristics, 2008
The Multidimensional Knapsack/Covering Problem (KCP) is a 0-1 Integer Programming Problem contain... more The Multidimensional Knapsack/Covering Problem (KCP) is a 0-1 Integer Programming Problem containing both knapsack and weighted covering constraints, subsuming the well-known Multidimensional Knapsack Problem (MKP) and the Generalized (weighted) Covering Problem. We propose an Alternating Control Tree Search (ACT) method for these problems that iteratively transfers control between the following three components: (1) ACT-1, a process that solves an LP relaxation of the current form of the KCP. (2) ACT-2, a method that partitions the variables according to 0, 1, and fractional values to create sub-problems that can be solved with relatively high efficiency. (3) ACT-3, an updating procedure that adjoins inequalities to produce successively more constrained versions of KCP, and in conjunction with the solution processes of ACT-1 and ACT-2, ensures finite convergence to optimality. The ACT method can also be used as a heuristic approach using early termination rules. Computational results show that the ACT-framework successfully enhances the performance of three widely different heuristics for the KCP. Our ACT-method involving scatter search performs better than any other known method on a large set of KCP-instances from the literature. The ACT-based methods are also found to be highly effective on the MKP.
Anvendt informatikk : eNytt, Desember 2007
Denne utgaven av Anvendt informatikk - eNytt inneholder fire utvalgte prosjekter ved avdeling for... more Denne utgaven av Anvendt informatikk - eNytt inneholder fire utvalgte prosjekter ved avdeling for økonomi, informatikk og samfunnsfag i høstsemesteret 2007. Rapportene som er presentert kan være noe forkortet i forhold til originalarbeidene, men de er ellers ikke redigert eller modifisert av redaksjonen eller andre
Anvendt informatikk : eNytt, Desember 2004
Anvendt informatikk : eNytt, Juni 2005
Anvendt Informatikk Enytt Desember 2006
Høgskolen i Molde, 2006
Denne utgaven av Anvendt informatikk - eNytt inneholder fire utvalgte prosjekter ved avdeling for... more Denne utgaven av Anvendt informatikk - eNytt inneholder fire utvalgte prosjekter ved avdeling for økonomi, informatikk og samfunnsfag i høstsemesteret 2006. I denne utgaven har vi en todelt rapport som er laget for å støtte programvaren "Engarde". Denne programvaren er mye brukt innen fektesporten og er nødvendig hvis en klubb skal kjøre en konkurranse. Den tredje rapporten er en forstudie om trådløsteknologi. Den fjerde er en brukerstudie
Anvendt informatikk : eNytt, Juni 2007
Opptrykk av studentarbeider i informatikk ved Hogskolen i Molde, Avdeling for okonomi, informatik... more Opptrykk av studentarbeider i informatikk ved Hogskolen i Molde, Avdeling for okonomi, informatikk og samfunnsfag.
Predicting match outcomes in association football using team ratings and player ratings
Statistical Modelling, 2020
The main goal of this article is to compare the performance of team ratings and individual player... more The main goal of this article is to compare the performance of team ratings and individual player ratings when trying to forecast match outcomes in association football. The well-known Elo rating system is used to calculate team ratings, whereas a variant of plus-minus ratings is used to rate individual players. For prediction purposes, two covariates are introduced. The first represents the pre-match difference in Elo ratings of the two teams competing, while the second is the average difference in individual ratings for the players in the starting line-ups of the two teams. Two different statistical models are used to generate forecasts. The first type is an ordered logit regression (OLR) model that directly outputs probabilities for each of the three possible match outcomes, namely home win, draw and away win. The second type is based on competing risk modelling and involves the estimation of scoring rates for the two competing teams. These scoring rates are used to derive match ...
[The risk of surgical glove perforations]
Tidsskrift for den Norske lægeforening : tidsskrift for praktisk medicin, ny række, Jan 29, 2007
The increasing prevalence of blood-borne viral diseases has drawn attention to the barrier betwee... more The increasing prevalence of blood-borne viral diseases has drawn attention to the barrier between the surgical personnel's hands and the patients body fluids during surgery. At present, the typical practice is to use double gloving in orthopaedic surgery, and single gloving in other types of surgery. The main purpose of our study was to estimate and compare the perforation risk in different categories of surgery. In a series of 655 surgical operations covering 5 main categories of surgery, all detected glove perforations were recorded and analysed. Perforations were found in 203 out of 655 operations (31%). The observed perforation frequency was 44.5% in gastrointestinal surgery, 34.7% in orthopaedic surgery, 31.1% in gynaecology, 18.6% in vascular surgery and 9.2% in general surgery. In some subcategories, the frequencies were even higher. In several categories of surgery, we found high perforation frequencies. Perforations in single gloves are often not detected during operat...
Fundamentalsof BrightnessStability-Ragauskas FO14 FUNDAMENTALS OF BRIGHTNESS STABILITY Brightness... more Fundamentalsof BrightnessStability-Ragauskas FO14 FUNDAMENTALS OF BRIGHTNESS STABILITY Brightness Reversion-Background The photoyellowing of mechanical pulp has been a research issue of high priority for more than 30 years. During this time, our understanding of this phenomenon has significantly increased. Early investigations by Leary _and others 2 demonstrated that the absorption of near UV light (3_=300-400nm) by the lignin component of mechanical pulp, in the presence of oxygen, leads to the yellowing. A variety of factors, such as pH, 3 metal salts,4 bleaching,5 moisture content, 3 and resin content 6 have been examined to determine their role in the brightness reversion phenomenon. To date, these investigations have not been successful in finding manufacturing conditions that significantly reduce the rate of photoyellowing for mechanical pulps.
Operations Research/Computer Science Interfaces Series
Optimal choice of production capacity in a random market
Stochastics An International Journal of Probability and Stochastic Processes, 1995
We consider the problem of choosing the right production capacity for a company operating in an u... more We consider the problem of choosing the right production capacity for a company operating in an unpredictable market. A mathematical formulation of the problem is given, and we are led to study a particular stochastic control problem. We find that under certain conditions, a solution to this problem exists, and the optimal control process is a finite variation process obtained
International Journal of Forecasting, 2010
Sports betting markets are becoming increasingly competitive. These markets are of interest when ... more Sports betting markets are becoming increasingly competitive. These markets are of interest when testing new ideas for quantitative prediction models. This paper examines the value of assigning ratings to teams based on their past performance in order to predict match results in association football. The ELO rating system is used to derive covariates that are then used in ordered logit regression models. In order to make informed statements about the relative merit of the ELO-based predictions compared to those from a set of six benchmark prediction methods, both economic and statistical measures are used. The results of large-scale computational experiments are presented.
Risk and risk management in organic and conventional cash crop farming in Norway
Food Economics - Acta Agriculturae Scandinavica, Section C, 2004
This study presents empirical insight into organic and conventional cash crop farmers’ perception... more This study presents empirical insight into organic and conventional cash crop farmers’ perceptions of risk and risk management strategies, and identifies socio-economic variables linked to these perceptions. The data originate from a questionnaire survey of farmers in Norway. The results indicate that organic farmers perceived themselves to be less risk averse than conventional farmers. For both groups, crop prices and
Tidsskrift for Den Norske Laegeforening, 2007
Den økte prevalensen av blodbåren smi e i befolkningen har sa søkelyset på barrieren mellom opera... more Den økte prevalensen av blodbåren smi e i befolkningen har sa søkelyset på barrieren mellom operasjonspersonellets hender og pasientens blod og kroppsvaesker ved kirurgi. Dagens praksis er å bruke doble operasjonshansker under ortopediske inngrep. Ved øvrige inngrep beny es vanligvis enkle hansker. Vi ønsket å kartlegge og sammenlikne risikoen for perforasjon av operasjonshansker ved ulike kategorier kirurgiske inngrep.
The Multidimensional Knapsack/Covering Problem (KCP) is a 0-1 Integer Programming Problem contain... more The Multidimensional Knapsack/Covering Problem (KCP) is a 0-1 Integer Programming Problem containing both knapsack and weighted covering constraints, subsuming the well-known Multidimensional Knapsack Problem (MKP) and the Generalized (weighted) Covering Problem. We propose an Alternating Control Tree Search (ACT) method for these problems that iteratively transfers control between the following three components: (1) ACT-1, a process that solves an LP relaxation of the current form of the KCP. (2) ACT-2, a method that partitions the variables according to 0, 1, and fractional values to create sub-problems that can be solved with relatively high efficiency. (3) ACT-3, an updating procedure that adjoins inequalities to produce successively more constrained versions of KCP, and in conjunction with the solution processes of ACT-1 and ACT-2, ensures finite convergence to optimality. The ACT method can also be used as a heuristic approach using early termination rules. Computational results show that the ACT-framework successfully enhances the performance of three widely different heuristics for the KCP. Our ACT-method involving scatter search performs better than any other known method on a large set of KCP-instances from the literature. The ACT-based methods are also found to be highly effective on the MKP.
Solution to a class of stochastic investment problems involving finite variation controls
Solution to a class of monotone stochastic control problems by variational inequality methods
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Papers by Halvard Arntzen