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| 2. |
- Aronsson, Martin, et al.
(författare)
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An Efficient MIP Model for Locomotive Scheduling with Time Windows
- 2006. - 1
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Ingår i: Dagstuhl Seminar Proceedings.
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Konferensbidrag (refereegranskat)abstract
- This paper presents an IP model for a vehicle routing and scheduling problem from the domain of freight railways. The problem is non-capacitated but allows non-binary integer flows of vehicles between transports with departure times variable within fixed intervals. Innovative features of the model include the use of boolean variables to separate the integer and continuous parts of the problem and maintaining the flow character of the integer part of the problem. The model has been developed with and has found practical use at Green Cargo, the largest freight rail operator in Sweden
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| 3. |
- Aronsson, Martin, et al.
(författare)
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MILP formulations of cumulative constraints for railway scheduling - A comparative study
- 2009. - 13
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Ingår i: The Proceedings of the 9th Workshop on Algorithmic Methods and Models for Optimization of Railways (ATMOS). - : Internationales Begegnungs- und Forschungszentrum für Informatik (IBFI), Schloss Dagstuhl, Germany.
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Konferensbidrag (refereegranskat)abstract
- This paper introduces two Mixed Integer Linear Programming (MILP) models for railway traffic planning using a cumulative scheduling constraint and associated pre-processing filters. We compare standard solver performance for these models on three sets of problems from the railway domain and for two of them, where tasks have unitary resource consumption, we also compare them with two more conventional models. In the experiments, the solver performance of one of the cumulative models is clearly the best and is also shown to scale very well for a large scale practical railway scheduling problem.
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| 4. |
- Aronsson, Martin, et al.
(författare)
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Mixed integer-linear formulations of cumulative scheduling constraints - A comparative study
- 2007. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper introduces two MILP models for the cumulative scheduling constraint and associated pre-processing filters. We compare standard solver performance for these models on three sets of problems and for two of them, where tasks have unitary resource consumption, we also compare them with two models based on a geometric placement constraint. In the experiments, the solver performance of one of the cumulative models, is clearly the best and is also shown to scale very well for a large scale industrial transportation scheduling problem.
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| 5. |
- Björck, Lennart, et al.
(författare)
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Tveksam vinst med ekolantbruk
- 2009
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Ingår i: Svenska dagbladet. - 1101-2412. ; -
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 6. |
- Bohlin, Markus, et al.
(författare)
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Ansatser för flexibel planering och schemaläggning av tågtidtabeller
- 2006. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten beskriver möjliga ansatser för att lösa det abstraherade tidtabellproblemet som bl.a. diskuteras i rapporten "Leveranstågplan: Specifikation och åtagande" (DDTP Arbetsdokument SICS-DDTP-002). Till grund för de olika ansatserna ligger en modell med avgångstider och hålltider (dvs. väntetider och i viss mån traverseringstider) som tillåts variera inom vissa tidsintervall. Huvudidén är att arbeta med förenklade kapacitetsvillkor på bana och bangård, för att på ett effektivt sätt kunna beräkna tidtabeller på en nivå som tillåter anpassning av tidtabellen till det gällande transportbehovet och den rådande trafiksituationen.
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| 7. |
- Foghagen, Christer
(författare)
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Öländska platser : anslagstavlor i synliggörandets geografi
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is an explorative excursion into the concept of place creation and place construction. It departures from the way place is discussed within both relational theory and humanistic geography. In pace with changes in the local economy and re-structure of the agricultural sector, the Swedish island, Öland, has gone through changes which has given new perspectives on place and the distinctiveness of single places. These changes have assigned new roles for single places and the processes of place creation and place construction takes new paths in these changes.The study focuses on three major research questions:• How is place created?• How are processes of place creation manifested on Öland?• What role does the distinctiveness of particular places have for tourism and entrepreneurship on the island Öland?The approach to these questions is explorative. Place is studied as a concept which both reflects and influences processes of change in relation to other places and different actors, people and organizations. In this study, place creation is analyzed in relation to changing economic, social and cultural aspects. People’s actions in a certain place or in different places affect place transformation and creation of place just as changes in the national and global economy do. The different images people have of a certain place and their actions in this place are affected by relations to other places and cultural values, identities, global trends and the overall economy. This plays a vital role for place creation and how distinct places are constructed. This study explores these processes on Öland through three different projects or case studies. Methodologically, I have a qualitative approach to my research questions and the case studies are based on interviews, observations and analyses of marketing material, information material, texts and pictures.
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| 8. |
- Forsgren, Malin, et al.
(författare)
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A Novel Approach to Railway Planning
- 2009. - 14
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Konferensbidrag (refereegranskat)abstract
- Today, detailed railway timetables in Sweden are published up to a year in advance, despite being based on volatile facts. We describe a new railway planning concept for Banverket, the Swedish Rail Administration, that aims to reduce the workload and increase the timetable quality, thus making railway traffic more cost-effective and attractive. The concept distinguishes between deliverables and production plans. The former are settled early and involve a selection of arrival and departure times that Banverket promises to deliver to the operators. The latter are fixed later, and only when sufficient information is available.
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| 9. |
- Forsgren, Malin, et al.
(författare)
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Tågtrafikplanering med successiv tilldelning
- 2009. - 5
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Idag konfliktregleras tågtrafiken i Sverige på sekundnivå redan i tidtabelläggningsfasen då operatörernas ansökningar har kommit in till Banverket, trots hög osäkerhet i planeringsunderlaget. Den här rapporten beskriver en tidtabelläggningsprocess där den detaljerade planeringen skjuts upp tills mer tillförlitliga fakta finns att tillgå. För den tidiga fasen föreslås i stället en mer översiktlig -- grov -- planering, vilken huvudsakligen mynnar ut i ett antal ankomster och avgångar som Banverket åtar sig att leverera punktligt till operatörerna. Poängen är att Banverket på så vis kan skjuta på besluten angående det som ska hända mellan åtagandepunkterna, och vi presenterar en konkret metod för hur detaljeringen som följer på den grova planeringen kan gå till. Metoden producerar en plan med en detaljeringsnivå som i stort överensstämmer med den i Banverkets tidtabelläggningssystem TrainPlan
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| 10. |
- Grelle, A., et al.
(författare)
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Large carbon-sink potential by Kyoto forests in Sweden - A case study on willow plantations
- 2007
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Ingår i: Tellus Series B-Chemical and Physical Meteorology. - : Stockholm University Press. - 0280-6509 .- 1600-0889. ; 59:5, s. 910-918
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Tidskriftsartikel (refereegranskat)abstract
- Fluxes of CO were measured in a 75-ha short-rotation willow plantation at Enkoping, central Sweden. The plantation was irrigated with wastewater for fertilization and water-filtering purposes. The harvested biomass was used locally for combined heat and power production. The plantation was a sink of ca. 8 tonnes C ha(-1) during 2003, of which ca. 50% was estimated to be attributed to fertilization. Biomass increment by shoot growth was 5 tonnes C ha-1 during the same year. Belowground carbon allocation was estimated to 3 tonnes C ha(-1) yr(-1) by a model that relates carbon allocation to shoot growth. Thus, the ecosystem carbon balance was closed by these estimations. The carbon uptake by the willow plantation was 5.5 times as high compared to a normally managed spruce forest, but only half as high as from an experimental, well-roanaged willow plantation in the same region. This illustrates the vast potential of short-rotation willow plantations for CO2 uptake from the atmosphere.
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