December 2024
·
2 Reads
·
1 Citation
Maritime Transport Research
What is this page?
This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.
Publications (66)
November 2024
·
13 Reads
Agricultural Systems
Highlights • Quantitative framework to explore economic-climatic synergies and trade-offs in dual purpose cattle systems. • Measures reported to produce economic-climatic win-wins can also produce lose-win and win-lose outcomes. • The economic-climatic effectiveness of different measures depends on operational circumstances. • Important to tailor economic-climatic advice to farmers based on their specific operational circumstances.
October 2024
·
10 Reads
·
1 Citation
After the expansion of the FIFA World Cup from 32 to 48 teams starting in the 2026 edition, the initial proposal was to split the 48 national teams into 16 groups of three. Among other drawbacks, this proposal provides potential for collusion. Recently, after widespread criticism, FIFA officials decided to revisit that proposal, instead approving a tournament with 12 groups of four teams. However, the approved format does not eliminate the possibility of collusion. In this chapter, we propose tournament formats for a World Cup with 12 groups of four teams, considering several criteria, such as non-collusion, symmetry in rest days, and no dead rubbers. At the same time, our proposals attempt to adhere to the traditional format, with some nuances in either the group or elimination stage.
June 2024
·
14 Reads
·
4 Citations
Agricultural Systems
May 2024
·
1 Read
May 2024
·
40 Reads
·
1 Citation
Transportation Research Part E Logistics and Transportation Review
This paper provides guidance for local authorities in small cities by equipping them with tools to comprehend and quantify freight consolidation within their urban areas, enabling them to integrate this into their regulatory decisions for enhanced city livability. Rather than advocating specific regulatory measures to facilitate consolidation, which is a political decision and can change over time, the paper establishes a basis for making informed policy decisions concerning consolidation. In this context, we focus on the perspective of authorities and, through an analysis of diverse market structures characterized by different degrees of consolidation, identify what is important to achieve in order to enhance city livability, measured by driven distance as well as the number and duration of stops. To this end, we propose a policy guidance framework tailored for authorities in small cities, adopting vehicle routing models as micro models to evaluate macro consolidation impacts for authorities. We apply the framework to a case that represents parcel distribution in Bergen, a small medieval city in Norway with a complicated street pattern and lack of parking, based on real maps and real demand patterns. Our findings suggest that small carriers take up a substantial space in the city, and increase the duration of stops while parking at various locations for parcel delivery. In this context, the city would benefit greatly from a market scheme, in which small carriers cannot deliver goods to end-customers, far more than moving between complete consolidation and a few reasonably large carriers.
March 2024
·
4 Reads
Journal of the Operational Research Society
![The effect of J∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$J^{*}$$\end{document} on the trade-off between the users’ efficiency](https://www.researchgate.net/publication/374116061/figure/fig1/AS:11431281204285473@1699671542545/The-effect-of-Jdocumentclass12ptminimal-usepackageamsmath-usepackagewasysym_Q320.jpg)
September 2023
·
94 Reads
·
4 Citations
Computational Management Science
Given two sets of objects, the integer assignment problem consists of assigning objects of one set to objects in the other set. Traditionally, the goal of this problem is to find an assignment that minimizes or maximizes a measure of efficiency, such as maximization of utility or minimization of cost. Lately, the interest in incorporating a measure of fairness in addition to efficiency has gained importance. This paper studies how to incorporate these two criteria in an integer assignment, using the Jain’s index as a measure of fairness. The original formulation of the assignment problem with this index involves a non-concave function, which renders a non-linear non-convex problem, usually hard to solve. To this aim, we develop two reformulations, where one is based on a quadratic objective function and the other one is based on integer second-order cone programming. We explore the performance of these reformulations in instances of real-world data derived from an application of assigning personnel to projects, and also in instances of randomly generated data. In terms of solution quality, all formulations prove to be effective in finding solutions capturing both efficiency and fairness criteria, with some slight differences depending on the type of instance. In terms of solving time, however, the performances of the formulations differ considerably. In particular, the integer quadratic approach proves to be much faster in finding optimal solutions.
June 2023
·
1 Read
International Transactions in Operational Research
May 2023
·
70 Reads
·
3 Citations
International Transactions in Operational Research
This paper surveys recent literature on decision support for beef and dairy farming, covering 110 articles published between 2016 and 2022. We classify these articles based on the type of farm, country of application, objectives and decisions, model scope, and methodology. The paper provides guidance for future research efforts by discussing the choice between whole farm and intrafarm modeling, the choice between optimization and simulation, and how to leverage existing modeling frameworks. Additionally, we identify opportunities for future research and discuss possibilities for increasing the adoption of decision‐support tools in practice by farmers and industry advisors.
Citations (49)
... However, that format had the serious drawback of possible collusion à la 'Disgrace of Gijón'; that is, the teams playing in the last match of a group could agree on a desired result that would qualify both for the next round, at the expense of the third team in the group (Chater et al., 2021;Guyon, 2020;Kendall & Lenten, 2017). 1 Thus, after heated debates and in light of the thrilling group stage of the 2022 FIFA World Cup, FIFA changed its mind, deciding in March 2023 that the new format would feature 12 groups of four teams. In this format, each team plays three matches, and the top two teams from each groupalong with the eight best third-placed teamsadvance to the round of 32 (Guajardo & Krumer, 2024). ...
- Citing Chapter
October 2024
... In combined milk and beef production on dairy farms, several measures have been reported to improve economic performance and reduce emission intensities. These include increased milk yield per cow (Zehetmeier et al., 2020;Jayasundara et al., 2019;Vellinga and de Vries, 2018;O'Brien et al., 2015;Hagemann et al., 2011;Zehetmeier et al., 2012), increased longevity of cows (Clasen et al., 2024;Zehetmeier et al., 2020;Vellinga and de Vries, 2018;Grandl et al., 2019;Bell et al., 2015;Weiske et al., 2006), reduced age at first calving Salte et al., 2020;Dall-Orsoletta et al., 2019;Hansen et al., 2019;Hutchison et al., 2017;Allendorf and Wettemann, 2015;Hansen et al., 2005), and intensification of beef production from bulls (Bang et al., 2024;Hansen et al., 2019;Hansen et al., 2005;Murphy et al., 2017;McGee et al., 2022). However, trade-offs may exist, especially in multifunctional systems such as combined milk and beef production. ...
- Citing Article
June 2024
Agricultural Systems
... In fact, this is important to capture because, as shown in Orhan et al. (2024a), small carriers drastically reduce the livability of cities in urban areas. Accordingly, contrary to the existing literature, we provide information and insights to authorities while also accounting for carriers of varying sizes, offering a holistic view of the market. ...
- Citing Article
May 2024
Transportation Research Part E Logistics and Transportation Review
... Problem P E is nonlinear and non-convex and hence challenging to solve due to (i) the nonlinear and non-convex equality constraints (3) and (9a), (ii) the non-convex constraints (8), (10) and (11) that include voltage and current phasors, and (iii) the maximization of the Jain's fairness index in objective (2) that is nonlinear and non-concave [36]. The aforementioned issues are addressed in the next section. ...
- Citing Article
- Full-text available
September 2023
Computational Management Science
... Research on lesser-known products or technologies for adoption could ultimately influence the U.S. beef production landscape [47], but both time and financial constraints exist. As such, there are limitations in the breadth of information generated, which increases the need for research that joins together multiple disciplines as well as practitioners in the research process [48]. Public-private partnerships also play an important role [49], and studies at the national and sub-national level can provide an enhanced value [50]. ...
- Citing Article
May 2023
International Transactions in Operational Research
... Round-robin tournaments have been widely investigated within the operational research (OR) community. Previous contributions have focused on a range of topics related to scheduling, such as minimising breaks between home and away matches (Durán et al., 2017;Rasmussen and Trick, 2007), minimising travel distances (Osicka & Guajardo, 2023;, rescheduling matches (Yi & Goossens, 2023), scheduling during holidays (Kendall, 2008), optimising the venue usage (Li et al., 2023;Van Bulck & Goossens, 2020) and making referee assignments (Duarte et al., 2007;Trick et al., 2012;Yavuz et al., 2008). 3 This paper contributes to several strands in the literature on round-robin tournaments. ...
- Citing Article
April 2023
Sports Economics Review
... The proposed approach can be used by tournament designers to evaluate alternative schedules at the time of the group draw, and choose an option that minimises the probability of matches with misaligned incentives. However, more radical interventions-such as dynamic scheduling (Guajardo and Krumer, 2023;Krumer et al., 2023;Stronka, 2024), opponent choice (Guyon, 2020;Hall and Liu, 2024), or randomised tie-breaking (Stronka 2024)-would be necessary against tanking. The remainder of the paper is organised as follows. ...
- Citing Article
January 2023
SSRN Electronic Journal
... The implementation of the models ensured a number of days off before each match that was well balanced across all teams while enabling the league to conclude a full season without cancelling any matches or changing the schedule format, unlike what occurred in many other leagues. Details on this project are found in Durán et al. (2022). ...
- Citing Article
- Full-text available
June 2022
... For a long time, most real-life sports tournaments have been scheduled by hand. During the last two decades, sports timetabling research yielded several dedicated algorithms, and the publication of numerous successful real-life applications (see e.g., Goossens and Spieksma [15], Ribeiro and Urrutia [34], Recalde et al [33], Westphal [51], Van Bulck et al [47], Durán et al [9]). The performance of these algorithms was typically evaluated by comparing one or two timetables to those manually created by expert practitioners. ...
- Citing Article
September 2021
INFORMS Journal on Applied Analytics
... In response to climate-related issues, various countries have adopted carbon emissions trading (CET) policies to reduce carbon emissions and realize carbon neutral. The European Union was the first to implement a CET scheme, which has since been adopted by 20 other countries, including the United States and Australia (Chai et al., 2018;Orhan and Guajardo, 2022;Peng et al., 2023). ...
- Citing Article
June 2021
International Transactions in Operational Research