| 1. |
- Aronsson, Martin, et al.
(författare)
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ACOOR Rapport 1; Tuff: Systemöversikt och arkitektur
- 2000. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- TUFF är ett verktyg för strategisk planering av tågrörelser och resursomlopp (f.n. lok). Det unika med TUFF är inte att kunna utföra dessa planeringar var för sig, utan att de kan samverka. Detta är möjligt dels genom att de ingående komponenterna kan hantera vagare data, t.ex. tidsintervall i stället för fasta tider vilket är det vanliga annars bland kommersiella lösningar, dels att det finns en samordningsfunktion, som vi kallar samordningsagent, som samordnar olika planer från olika planeringsfunktioner. Denna samordnare är programmerbar via ett speciellt språk, så att ett stort problem kan splittras upp i mindre delar, och resultat från olika planeringar av dessa delar kan sedan kombineras och nya resultat genereras. Tanken med denna integrering av olika planeringsfunktioner är att åstadkomma globalt bättre lösningar, jämfört med när varje problem löses var för sig, genom att ta hänsyn till varje planeringsproblems krav tidigt i planeringscykeln.
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| 2. |
- Lindblom, Simon, et al.
(författare)
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ACOOR Rapport 2: Översikt av tekniker och metoder
- 2000. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I arbetet med att modellera ett produktionsplaneringsproblem i järnvägsindustrin har vi identifierat ett antal metoder och tekniker som vi hävdar är användbara även utanför järnvägsdomänen. I denna rapport presenterar vi kort problemställningarna i järnvägsdomänen, presenterar de viktigaste av de tekniker vi identifierat, använt och utvecklat samt indikerar en del andra problemdomäner för vilka vi bedömer att dessa tekniker skulle kunna användas.
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| 3. |
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| 4. |
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| 5. |
- Abrahamsson, Henrik, et al.
(författare)
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From QoS provisioning to QoS charging
- 2002. - 1
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Ingår i: Proceedings of the Second International Workshop on Internet Charging and QoS Technologies, ICQT 2002. ; , s. 135-144
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Konferensbidrag (refereegranskat)
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| 6. |
- Alonso, Juan, et al.
(författare)
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Objective Functions for Balance in Traffic Engineering
- 2002. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We prove a result concerning objective functions that can be used to obtain efficient and balanced solutions to the multi-commodity network flow problem. This type of solution is of interest when routing traffic in the Internet. A particular case of the result proved here (see Corollary 2 below) was stated without proof in a previous paper.
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| 7. |
- Aronsson, Martin, et al.
(författare)
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A constraint model for a cyclic time personnel routing and scheduling problem
- 2001. - 6
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present a crew scheduling problem with time windows in the context of scheduling train personnel, which encompasses not only assignment of resources to tasks but also the introduction of extra tasks, passive journeys, depending on the problem instance. The representation of the problem is made as a constraint program, which relies heavily on some global constraints, notably a constraint for expressing non-overlap between rectangles on a surface. A search algorithm is described and we also point out some problems and deficiencies of the current model and its computational behaviour.
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| 8. |
- Aronsson, Martin, et al.
(författare)
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Coordination of planning processes for traffic operators on rail networks; Annual Report 1, Swedish national railway administration (Banverket) R&D-project - SPOK
- 2003. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This project is concerned with how to improve the capacity allocation process. In particular the project aims at proposing an enhanced format for train path applications, study the technical limitations for timetabling support tools and in the longer term to implement support systems for the train path allocation process. This report describes the various factors that affect the application process, and report the opinions from several actors in the field. Since the deregulation of the Swedish railway, and with new EU directives, the foundations for the capacity allocation process is changing rapidly. There is a strong need for clear and predictable principles that are fair and operator neutral and implements the prioritisation given to different types of traffic and for improved methodologies and decision support tools in the capacity allocation process. This is crucial to support both the possibility for the traffic operators to state demands and the timetable designers in judging conflicting train paths. A conclusion is that almost all the requirements on the timetable presented in this report can in fact be stated as properties and relations of events in the timetable.
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| 9. |
- Aronsson, Martin, et al.
(författare)
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Översikt av metoder och förutsättningar för tåglägestilldelning
- 2003. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport beskriver status hos den forskning som är relevant för tåglägestilldelning samt analyserar och kommenterar några av de reglerande dokument såsom lagar och förordningar samt instruktioner och information som Banverket och Tågtrafikledningen tagit fram. för att styra tåglägestilldelningsprocessen. Rapporten ger också en översikt av forskningsfronten vad gäller systemstöd för tåglägestilldelningen och ger en kortfattad en beskrivning av några av de tekniker som kan vara användbara i ett stödsystem för tåglägestilldelning samt lyfter fram deras respektive för och nackdelar.
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| 10. |
- Aurell, Erik, et al.
(författare)
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GENFUNK
- 2002. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This document summarizes the results obtained by SICS in project GENFUNK (2001). The project was carried out in collaboration with Global Genomics AB (Stockholm, Sweden). Jointly obtained results will be presented separately. Main funding was provided by Swedish Research Agency VINNOVA. Project GENFUNK studied a novel approach of measuring the global gene expression. In the method, mRNA is extracted from a tissue sample and transformed into cDNA captured on magnetic beads. This is then acted on by type IIS restriction endonucleases, which recognize certain short DNA sequences and cut the DNA close to those sequences. The resulting fragments are amplified in PCR with selected ligation fragments, and displayed in capillary electrophoresis. Determining the gene expression levels from the peak data is combinatorial optimization problem, which can in principle be solved, to give expression levels of most genes active in sampled cells, with good accuracy.
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| 11. |
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| 12. |
- Bohlin, Markus, et al.
(författare)
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Designing Global Scheduling Constraints for Local Search: A Generic Approach
- 2002. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this work we present a novel method to automate the computation of global constraints cost for local search. The method is based on the representation of a global constraints as graph properties on a binary constraint network. This formulation simplifies the implementation of global constraints in local search, and provides a cost that can be readily compared to one obtained for subproblems using binary constraints exclusively. The cost obtained can be efficiently updated during the search using incremental methods. The representation of a global constraint as outlined above can also be used for generation of suitable neighborhoods for the constraint. This is done using simple repair functions applied on the elementary constraints in the global constraint graph. We show the usability of our approach by presenting formulations of global constraints in non-overlapping and cumulative scheduling.
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| 13. |
- Ekman, Jan, et al.
(författare)
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En analytisk metod för utredning av kapacitet vid signalprojektering
- 2003. - 5
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Detta är slutrapporten till projektet "Beslutsstöd för utredning av kapacitetsfrågor vid signalprojektering," utfört av SICS AB under perioden januari 2002 - mars 2003 och finansierat av Banverkets FoU-program. Rapporten beskriver en metod att beräkna kapacitet, där kapacitet avser antalet tåg som per tidsenhet går att framföra genom ett spårområde. Metoden beräknar minsta tiden för en upprepning hos en periodiskt upprepad trafik. I rapporten införs begreppen fri väg och trafikering för att resonera om kapacitet. Dessa begrepp är centrala för metoden och delar upp beräkningen i två delar. Den ena delen utgörs av framtagandet av värden som hör samman med de införda begreppen, från data om bland annat fordon och infrastruktur. Beräkningen av kapacitet från dessa värden utgör den andra delen. Rapporten ger en detaljerad beskrivning av hur man går till väga för att använda metoden, bevis av det grafteoretiska påstående som metoden baseras på och uppskattning av metodens beräkningskomplexitet. Rapporten innehåller också en diskussion kring vad utredning av kapacitet innebär, resonemang kring målet med ett visst kapacitetskrav och förslag på hur kapacitet kravställs. Vid signalprojektering kan metoden användas både till snabba ungefärliga och till noggranna uppskattningar av kapacitet. Lämpliga sätt att använda metoden är att jämföra olika sätt att placera signaler, jämföra ett antal trafiklösningar på en bangård och att jämföra olika val av mötesstationer på en enkelspårssträcka.
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| 14. |
- Gillblad, Daniel, et al.
(författare)
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The gmdl Modeling and Analysis System
- 2004. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes the gmdl modeling and analysis environment. gmdl was designed to provide powerful data analysis, modeling, and visualization with simple, clear semantics and easy to use, well defined syntactic conventions. It provides an extensive set of necessary for general data preparation, analysis, and modeling tasks.
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| 15. |
- Holst, Anders, et al.
(författare)
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Butler: Fallanalys 1 - Outokumpu
- 2004. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport beskriver resultatet av en dataanalys gjord på produktionsdata från Outokumpu:s valsverk i Avesta. Syftet har varit att fastställa samband mellan övriga produktionsparametrar och uppkomsten av sk. "slivers" en typ av ytlig sprick- eller veck-bildning i det färdiga stålet. Ett annat syfte har varit att studera metodologiska frågor i ett arbete av detta slag.
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| 16. |
- Jemth, Per, et al.
(författare)
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Biosynthetic oligosaccharide libraries for identification of protein-binding heparan sulfate motifs : exploring the structural diversity by screening for fibroblast growth factor (FGF)1 and FGF2 binding.
- 2002
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 277:34, s. 30567-30573
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Tidskriftsartikel (refereegranskat)abstract
- Heparan sulfate is crucial for vital reactions in the body because of its ability to bind various proteins. The identification of protein-binding heparan sulfate sequences is essential to our understanding of heparan sulfate biology and raises the possibility to develop drugs against diseases such as cancer and inflammatory conditions. We present proof-of-principle that in vitro generated heparan sulfate oligosaccharide libraries can be used to explore interactions between heparan sulfate and proteins, and that the libraries expand the available heparan sulfate sequence space. Oligosaccharide libraries mimicking highly 6-O-sulfated domains of heparan sulfate were constructed by enzymatic O-sulfation of O-desulfated, end-group (3)H-labeled heparin octasaccharides. Acceptor oligosaccharides that were 6-O-desulfated but only partially 2-O-desulfated yielded oligosaccharide arrays with increased ratio of iduronyl 2-O-sulfate/glucosaminyl 6-O-sulfate. The products were probed by affinity chromatography on immobilized growth factors, fibroblast growth factor-1 (FGF1) and FGF2, followed by sequence analysis of trapped oligosaccharides. An N-sulfated octasaccharide, devoid of 2-O-sulfate but with three 6-O-sulfate groups, was unexpectedly found to bind FGF1 as well as FGF2 at physiological ionic strength. However, a single 2-O-sulfate group in the absence of 6-O-sulfation gave higher affinity for FGF2. FGF1 binding was also augmented by 2-O-sulfation, preferentially in combination with an adjacent upstream 6-O-sulfate group. These results demonstrate the potential of the enzymatically generated oligosaccharide libraries.
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| 17. |
- Kocjan, Waldemar, et al.
(författare)
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Filtering methods for symmetric cardinality constraint
- 2004. - 5
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Ingår i: Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems. - Berlin, Heidelberg : Springer. - 9783540218364 ; , s. 200-208
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Konferensbidrag (refereegranskat)abstract
- The symmetric cardinality constraint is described in terms of a set of variables X={x1,...,xk}, which take their values as subsets of values V={v1,...,vn}. It constraints the cardinality of the set assigned to each variable to be in an interval [lxi,cxi] and at the same time it restricts the number of occurrences of each value vj in V in the sets assigned to variables in X to be in an other interval [lvj,cvj]. In this paper we introduce the symmetric cardinality constraint and define set constraint satisfaction problem as a framework for dealing with this type of constraints. Moreover, we present effective filtering methods for the symmetric cardinality constraint.
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| 18. |
- Kocjan, Waldemar, et al.
(författare)
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Filtering methods for symmetric cardinality constraint
- 2003. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The symmetric cardinality constraint is described in terms of variables X = {x_1,...,x_k} which take values in the subset of values V={v_1,...,v_n}. It constraints the number of times a value can be assigned to a variable in X to be in an interval [l_{x_i},c_{x_i}] and at the same time it restricts the number of values in V which any variable can take to an interval [l_{v_j},c_{v_j}]. In this paper we introduce the symmetric cardinality constraint and define set constraint satisfaction problem as a framework for dealing with this type of constraints. Moreover, we present effective filtering methods for the symmetric cardinality constraint.
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| 19. |
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| 20. |
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| 21. |
- Kreuger, Per, et al.
(författare)
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Sequence dependent task extensions for trip scheduling
- 2001. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A constraint model for scheduling train trips on a network of tracks used in both directions, using a headway abstraction is described. We argue that a generalisation of a straightforward job-shop scheduling formulation using sequence dependent task extensions can decrease the required resolution of network representation and hence problem size. A geometric interpretation of the model of the constraints that can be used to visualise schedules is presented. Preliminary ideas on search heuristics are presented with performance results and a set of examples.
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| 22. |
- Lindblom, Simon, et al.
(författare)
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Task Structure Abstraction
- 2001. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper explores the idea of using formalised abstraction as means of describing various operations on structured representations of planing, scheduling and resource allocation problems. We define a notion of structures on tasks, relations and resources. Each task consists of task parameters and an inductively defined substructure. The task parameters denote domain variables constrained by the relations of the structure while resources formalises resource constraints, typically presupposing the semantics of some global constraint. A notion of consistency of such structures is briefly outlined. We go on characterise properties of safeness and certain conservation properties on operations We claim that such properties are relevant to problem domains where tasks on several different types or levels of resources has to scheduled simultaneously or by partitioning the problem into several subproblems that has then to be coordinated. Finally we present, in some detail, a model of such a problem from the rail transport industry formalised as several task structures. We show how operations on these can be seen as solvers for the various subproblems but also used to transform a specification or a solution of one subproblem into a specification of an other one. We claim that properties of such operations can be used to characterise reasoning in coordination problems.
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| 23. |
- Linnarsson, Sten, et al.
(författare)
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METHODS FOR PROFILING MOLECULES WITH AN OBJECTIVE FUNCTION
- 2003. - 18
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Patent (populärvet., debatt m.m.)abstract
- Methods relating to profiling and/or identifying molecules in a sample, particularly chemical or biological molecules contained in an experimental sample using measured data about molecules actually present and known information about candidate molecules that may be present. Information tags can be assigned to candidates. This may be achieved with a high degree of accuracy and a low false positive rate by minimising the effect of one or more possible sources of error. An objective goal (assignment) may be optimised by linear programming or by mixed integer programming
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| 24. |
- Sjöland, Thomas, et al.
(författare)
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Heterogeneous scheduling and rostering
- 2001. - 1
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Ingår i: ALP Newsletter for Logic Programming.
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Tidskriftsartikel (refereegranskat)abstract
- We have designed and implemented a distributed model for planning and scheduling of transports in a railway company which is usable also for other production planning problems. Our model emphasises the use of an agent for the co-ordination of distinct sub-problems occurring in railway scheduling such as for instance the allocation of track resources to transports, the allocation of vehicles to transports, and the allocation of staff to perform the transportation tasks. Using constraints as the key technology, we are interested in finding interfacing principles to combine several solvers to allow users, for instance reasoning agents, to have a uniform view of the combined constraint store of heterogeneous solvers. Abstraction of constraint stores is an important technique used to enable translations between heterogeneous solvers and to improve performance of the overall combined problem of producing a railway schedule. By using abstractions of relevant representations we achieve a hierarchical system which by focusing attention on different levels of abstraction can achieve an acceptable solution faster than previous techniques.
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| 25. |
- Sjöland, Thomas, et al.
(författare)
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Heterogeneous scheduling and rotation
- 2002. - 1
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Ingår i: Computational Logic: Logic Programming and Beyond, Part I.. ; Springer LNAI 2407, s. 655-676
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Tidskriftsartikel (refereegranskat)abstract
- This article highlights an application in the area of decision support for planning transports in a railway company utilising constraint programming and a flexible design which has been sucessfully tested on real world data. We discuss the problem formulation for the co-ordination of distinct subproblems, the allocation of track resources to transports, the allocation of vehicles to transports, and the allocation of personnel to perform the transportation tasks in a railway company and the development of heterogenous constraint model which is usable also for other production planning problems. Using constraints as the key technology, we discuss approaches to find interfacing principles to combine several solvers.
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