| 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. |
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| 3. |
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| 4. |
- Lindblom, Simon, et al.
(författare)
-
ACOOR Rapport 2: Översikt av tekniker och metoder
- 2000. - 1
-
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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| 5. |
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Abrahamsson, Henrik, et al.
(författare)
-
From QoS provisioning to QoS charging
- 2002. - 1
-
Ingår i: Proceedings of the Second International Workshop on Internet Charging and QoS Technologies, ICQT 2002. ; , s. 135-144
-
Konferensbidrag (refereegranskat)
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| 10. |
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| 11. |
- Alonso, Juan, et al.
(författare)
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Objective Functions for Balance in Traffic Engineering
- 2002. - 1
-
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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| 12. |
- Aronsson, Martin, et al.
(författare)
-
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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| 13. |
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| 14. |
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| 15. |
- Aronsson, Martin, et al.
(författare)
-
An Efficient MIP Model for Locomotive Routing and Scheduling
- 2010. - 9
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Konferensbidrag (refereegranskat)abstract
- This paper presents a MIP model for a locomotive routing and scheduling problem from the domain of freight railways. Innovative features of the model include the use of binary variables to separate the integer and continuous parts of the problem to maintain the flow character of the integer part of the problem. The model has been developed with, and has found practical Green Cargo, the largest rail freight operator in Sweden.
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| 16. |
- Aronsson, Martin, et al.
(författare)
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An Efficient MIP Model for Locomotive Scheduling with Time Windows
- 2006. - 1
-
Ingår i: Dagstuhl Seminar Proceedings.
-
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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| 17. |
- Aronsson, Martin, et al.
(författare)
-
Coordination of planning processes for traffic operators on rail networks; Annual Report 1, Swedish national railway administration (Banverket) R&D-project - SPOK
- 2003. - 1
-
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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| 18. |
- 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.
-
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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| 19. |
- 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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| 20. |
- Aronsson, Martin, et al.
(författare)
-
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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| 21. |
- Arvidsson, Åke, et al.
(författare)
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Tracking user terminals in a mobile communication network
- 2011. - 7
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Patent (populärvet., debatt m.m.)abstract
- There is provided a method of tracking user terminals in a mobile communication network. The method comprising, at a tracking node, determining that a user terminal is located in a tracking area, storing data associated with the tracking area, the data comprising a number of observations of all user terminals at the tracking area at a first time, receiving a page response from the user terminal located in one of the tracking area and a further tracking area, and in the event that the user terminal remains located at the tracking area, updating the data to include the number of page responses received at the tracking area after a first time interval, and in the event that the user terminal is located at the further tracking area, updating the data to include the number of page responses received at the further tracking area after the first time interval.
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| 22. |
- Aurell, Erik, et al.
(författare)
-
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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| 23. |
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| 24. |
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| 25. |
- Bohlin, Markus, 1976-
(författare)
-
A Study of Combinatorial Optimization Problems in Industrial Computer Systems
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A combinatorial optimization problem is an optimization problem where the number of possible solutions are finite and grow combinatorially with the problem size. Combinatorial problems exist everywhere in industrial systems. This thesis focuses on solving three such problems which arise within two different areas where industrial computer systems are often used. Within embedded systems and real-time systems, we investigate the problems of allocating stack memory for an system where a shared stacks may be used, and of estimating the highest response time of a task in a system of industrial complexity. We propose a number of different algorithms to compute safe upper bounds on run-time stack usage whenever the system supports stack sharing. The algorithms have in common that they can exploit commonly-available information regarding timing behaviour of the tasks in the system. Given upper bounds on the individual stack usage of the tasks, it is possible to estimate the worst-case stack behaviour by analysing the possible and impossible preemption patterns. Using relations on offset and precedences, we form a preemption graph, which is further analysed to find safe upper-bounds on the maximal preemptions chain in the system. For the special case where all tasks exist in a single static schedule and share a single stack, we propose a polynomial algorithm to solve the problem. For generalizations of this problem, we propose an exact branch-and-bound algorithm for smaller problems and a polynomial heuristic algorithm for cases where the branch-and-bound algorithm fails to find a solution in reasonable time. All algorithms are evaluated in comprehensive experimental studies. The polynomial algorithm is implemented and shipped in the developer tool set for a commercial real-time operating system, Rubus OS. The second problem we study in the thesis is how to estimate the highest response time of a specified task in a complex industrial real-time system. The response-time analysis is done using a best-effort approach, where a detailed model of the system is simulated on input constructed using a local search procedure. In an evaluation on three different systems we can see that the new algorithm were able to produce higher response times much faster than what has previously been possible. Since the analysis is based on simulation and measurement, the results are not safe in the sense that they are always higher or equal to the true response time of the system. The value of the method lies instead in that it makes it possible to analyse complex industrial systems which cannot be analysed accurately using existing safe approaches. The third problem is in the area of maintenance planning, and focus on how to dynamically plan maintenance for industrial systems. Within this area we have focused on industrial gas turbines and rail vehicles. We have developed algorithms and a planning tool which can be used to plan maintenance for gas turbines and other stationary machinery. In such problems, it is often the case that performing several maintenance actions at the same time is beneficial, since many of these jobs can be done in parallel, which reduces the total downtime of the unit. The core of the problem is therefore how to (or how not to) group maintenance activities so that a composite cost due to spare parts, labor and loss of production due to downtime is minimized. We allow each machine to have individual schedules for each component in the system. For rail vehicles, we have evaluated the effect of replanning maintenance in the case where the component maintenance deadline is set to reflect a maximum risk of breakdown in a Gaussian failure distribution. In such a model, we show by simulation that replanning of maintenance can reduce the number of maintenance stops when the variance and expected value of the distribution are increased. For the gas turbine maintenance planning problem, we have evaluated the planning software on a real-world scenario from the oil and gas industry and compared it to the solutions obtained from a commercial integer programming solver. It is estimated that the availability increase from using our planning software is between 0.5 to 1.0 %, which is substantial considering that availability is currently already at 97-98 %.
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| 26. |
- Bohlin, Markus, et al.
(författare)
-
A Tool for Gas Turbine Maintenance Scheduling
- 2009. - 20
-
Ingår i: Proceedings of the Twenty-First Conference on Innovative Applications of Artificial Intelligence (IAAI'09). - : IEEE Computer Society. - 9781577354239
-
Konferensbidrag (refereegranskat)abstract
- We describe the implementation and deployment of a software decision support tool for the maintenance planning of gas turbines. The tool is used to plan the maintenance for turbines manufactured and maintained by Siemens Industrial Turbomachinery AB (SIT AB) with the goal to reduce the direct maintenance costs and the often very costly production losses during maintenance downtime. The optimization problem is formally defined, and we argue that feasibility in it is NP-complete. We outline a heuristic algorithm that can quickly solve the problem for practical purposes, and validate the approach on a real-world scenario based on an oil production facility. We also compare the performance of our algorithm with results from using mixed integer linear programming, and discuss the deployment of the application. The experimental results indicate that downtime reductions up to 65% can be achieved, compared to traditional preventive maintenance. In addition, using our tool is expected to improve availability with up to 1% and reduce the number of planned maintenance days with 12%. Compared to a mixed integer programming approach, our algorithm not optimal, but is orders of magnitude faster and produces results which are useful in practice. Our test results and SIT AB’s estimates based on operational use both indicate that significant savings can be achieved by using our software tool, compared to maintenance plans with fixed intervals.
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| 27. |
- Bohlin, Markus, et al.
(författare)
-
Ansatser för flexibel planering och schemaläggning av tågtidtabeller
- 2006. - 1
-
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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| 28. |
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| 29. |
- Bohlin, Markus, et al.
(författare)
-
Designing Global Scheduling Constraints for Local Search: A Generic Approach
- 2002. - 1
-
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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| 30. |
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| 31. |
- Bohlin, Markus, et al.
(författare)
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Searching for gas turbine maintenance schedules
- 2010
-
Ingår i: The AI Magazine. - : Wiley. - 0738-4602. ; 31:1, s. 21-36
-
Tidskriftsartikel (refereegranskat)abstract
- Preventive-maintenance schedules occurring in industry are often suboptimal with regard to maintenance coallocation, loss-of-production costs, and availability. We describe the implementation and deployment of a software decision support, tool for the maintenance planning of gas turbines, with the goal of reducing the direct maintenance costs and the often costly production losses during maintenance down time. The optimization problem is formally defined, and we argue that the feasibility version is NP-complete. We outline a heuristic algorithm that can quickly solve the problem for practical purposes and validate the approach on a real-world scenario based on an oil production facility. We also compare the performance of our algorithm with result's from using integer programming and d'iscuss the deployment of the application. The experimental results indicate that down time reductions up to 65 percent can be achieved, compared to traditional preventive maintenance. In addition, the use of our tool is expected to improve availability by up to 1 percent and to reduce the number of planned maintenance days by 12 percent. Compared to an integer programming approach, our algorithm is not optimal but is much faster and produces results that are useful in practice. Our test results and SIT AB's estimates based on operational use both indicate that significant savings can be achieved by using our software tool, compared to maintenance plans with fixed intervals.
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| 32. |
- Bohlin, Markus, et al.
(författare)
-
Simulation-Based Timing Analysis of Complex Real-Time Systems
- 2009
-
Ingår i: 2009 15TH IEEE INTERNATIONAL CONFERENCE ON EMBEDDED AND REAL-TIME COMPUTING SYSTEMS AND APPLICATIONS, PROCEEDINGS. - 9780769537870 ; , s. 321-328
-
Konferensbidrag (refereegranskat)abstract
- This paper presents an efficient best-effort approach for simulation-based timing analysis of complex real- time systems. The method can handle in principle any software design that can be simulated, and is based on controlling simulation input using a simple yet novel hill- climbing algorithm. Unlike previous approaches, the new algorithm directly manipulates simulation parameters such as execution times, arrival jitter and input. An evaluation is presented using six different simulation models, and two other simulation methods as reference: Monte Carlo simulation and MABERA. The new method proposed in this paper was 4-11% more accurate while at the same time 42 times faster, on average, than the reference methods.
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| 33. |
- Carlsson, Mats, et al.
(författare)
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Constraint-based resource allocation and scheduling in steel manufacturing
- 1999. - 1
-
Konferensbidrag (refereegranskat)abstract
- This paper describes a flow maximization problem in steel manufacturing, decomposes it into three sub-problems, and models them in terms of finite domain constraints. Greedy algorithms are used for solving the sub-problems. The constraints are used for maintaining consistency rules, not for optimization. A tool implementing these algorithms and equipped with a GUI has been implemented.
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| 34. |
- Corcoran, Diarmuid, et al.
(författare)
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A Sample Efficient Multi-Agent Approach to Continuous Reinforcement Learning
- 2022
-
Ingår i: Proceedings of the 2022 18th International Conference of Network and Service Management. - : Institute of Electrical and Electronics Engineers Inc.. - 9783903176515 ; , s. 338-344
-
Konferensbidrag (refereegranskat)abstract
- As design, deployment and operation complexity increase in mobile systems, adaptive self-learning techniques have become essential enablers in mitigation and control of the complexity problem. Artificial intelligence and, in particular, reinforcement learning has shown great potential in learning complex tasks through observations. The majority of ongoing reinforcement learning research activities focus on single-Agent problem settings with an assumption of accessibility to a globally observable state and action space. In many real-world settings, such as LTE or 5G, decision making is distributed and there is often only local accessibility to the state space. In such settings, multi-Agent learning may be preferable, with the added challenge of ensuring that all agents collaboratively work towards achieving a common goal. We present a novel cooperative and distributed actor-critic multi-Agent reinforcement learning algorithm. We claim the approach is sample efficient, both in terms of selecting observation samples and in terms of assignment of credit between subsets of collaborating agents.
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| 35. |
- Corcoran, Diarmuid, et al.
(författare)
-
Data driven selection of DRX for energy efficient 5G RAN
- 2017
-
Ingår i: 13th International Conference on Network and Service Management (CNSM), 2017. - Tokyo : IEEE conference proceedings. ; , s. 1-9
-
Konferensbidrag (refereegranskat)abstract
- The number of connected mobile devices is increasing rapidly with more than 10 billion expected by 2022. Their total aggregate energy consumption poses a significant concern to society. The current 3gpp (3rd Generation Partnership Project) LTE/LTE-Advanced standard incorporates an energy saving technique called discontinuous reception (DRX). It is expected that 5G will use an evolved variant of this scheme. In general, the single selection of DRX parameters per device is non trivial. This paper describes how to improve energy efficiency of mobile devices by selecting DRX based on the traffic profile per device. Our particular approach uses a two phase data-driven strategy which tunes the selection of DRX parameters based on a smart fast energy model. The first phase involves the off-line selection of viable DRX combinations for a particular traffic mix. The second phase involves an on-line selection of DRX from this viable list. The method attempts to guarantee that latency is not worse than a chosen threshold. Alternatively, longer battery life for a device can be traded against increased latency. We built a lab prototype of the system to verify that the technique works and scales on a real LTE system. We also designed a sophisticated traffic generator based on actual user data traces. Complementary method verification has been made by exhaustive off-line simulations on recorded LTE network data. Our approach shows significant device energy savings, which has the aggregated potential over billions of devices to make a real contribution to green, energy efficient networks.
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| 36. |
- Corcoran, Diarmuid, et al.
(författare)
-
Efficient Real-Time Traffic Generation for 5G RAN
- 2020
-
Ingår i: Proceedings of IEEE/IFIP Network Operations and Management Symposium 2020. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728149738
-
Konferensbidrag (refereegranskat)abstract
- Modern telecommunication and mobile networks are increasingly complex from a resource management perspective, with diverse combinations of software and infrastructure elements that need to be configured and tuned for efficient operation with high quality of service. Increased real-time automation at all levels and time-frames is a critical tool in controlling this complexity. A key component in automation is practical and accurate simulation methods that can be used in live traffic scenarios. This paper introduces a new method with supporting algorithms for sampling key parameters from live or recorded traffic which can be used to generate large volumes of synthetic traffic with very similar rate distributions and temporal characteristics. Multiple spatial renewal processes are used to generate fractional Gaussian noise, which is scaled and transformed into a log-normal rate distribution with discrete arrival events, fitted to the properties observed in given recorded traces. This approach works well for modelling large user aggregates but is especially useful for medium sized and relatively small aggregates, where existing methods struggle to reproduce the most important properties of recorded traces. The technique is demonstrated through experimental comparisons with data collected from an operational LTE network to be highly useful in supporting self-learning and automation algorithms which can ultimately reduce complexity, increase energy efficiency, and reduce total network operation costs.
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| 37. |
- Corcoran, Diarmuid, et al.
(författare)
-
Reinforcement Learning for Automated Energy Efficient Mobile Network Performance Tuning
- 2021
-
Ingår i: Proceedings of the 2021 17th International Conference on Network and Service Management. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 216-224, s. 216-224
-
Konferensbidrag (refereegranskat)abstract
- Modern mobile networks are increasingly complex from a resource management perspective, with diverse combinations of software, infrastructure elements and services that need to be configured and tuned for correct and efficient operation. It is well accepted in the communications community that appropriately dimensioned, efficient and reliable configurations of systems like 5G or indeed its predecessor 4G is a massive technical challenge. One promising avenue is the application of machine learning methods to apply a data-driven and continuous learning approach to automated system performance tuning. We demonstrate the effectiveness of policy-gradient reinforcement learning as a way to learn and apply complex interleaving patterns of radio resource block usage in 4G and 5G, in order to automate the reduction of cell edge interference. We show that our method can increase overall spectral efficiency up to 25% and increase the overall system energy efficiency up to 50% in very challenging scenarios by learning how to do more with less system resources. We also introduce a flexible phased and continuous learning approach that can be used to train a bootstrap model in a simulated environment after which the model is transferred to a live system for continuous contextual learning.
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| 38. |
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| 39. |
- Degerstedt, Oliver, et al.
(författare)
-
Quantitative imaging of doxorubicin diffusion and cellular uptake in biomimetic gels with human liver tumor cells
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Novel tumor-on-a-chip approaches are increasingly used to investigate tumor progression and potential treatment options. To improve the effect of any cancer treatment it is important to have an in-depth understanding of drug diffusion, penetration across the tumor extracellular matrix and cellular uptake. In this study, we have developed a miniaturized chip where drug diffusion and cellular uptake in different hydrogel environments can be quantified at high resolution using live imaging. Diffusion of doxorubicin was reduced in a biomimetic hydrogel mimicking tissue properties of cirrhotic liver and early stage hepatocellular carcinoma (362 ± 109 µm2/s) as compared to an agarose gel (571 ± 145 µm2/s, p = 0.0085). The diffusion was further lowered to 164 ± 33 µm2/s (p = 0.0023) by preparing the biomimetic gel in cell media instead of phosphate buffered saline. The addition of liver tumor cells (Huh7 or HepG2) to the gel, at two different densities, did not significantly influence drug diffusion. Clinically relevant and quantifiable doxorubicin concentration gradients (1-20 µM) were established in the chip within one hour. Intracellular increases in doxorubicin fluorescence correlated with decreasing fluorescence of the DNA-binding stain Hoechst 33342, and based on the quantified intracellular uptake of doxorubicin an apparent cell permeability (9.00 ± 0.74 x 10-4 µm/s for HepG2) was determined.
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| 40. |
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| 41. |
- Ekman, Jan, et al.
(författare)
-
En analytisk metod för utredning av kapacitet vid signalprojektering
- 2003. - 5
-
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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| 42. |
- Forsgren, Malin, et al.
(författare)
-
A Novel Approach to Railway Planning
- 2009. - 14
-
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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| 43. |
- Forsgren, Malin, et al.
(författare)
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The Maraca: a tool for minimizing resource conflicts in a non-periodic railway timetable
- 2011. - 9
-
Konferensbidrag (refereegranskat)abstract
- While mathematical optimization and operations research receive growing attention in the railway sector, computerized timetabling tools that actually make significant use of optimization remain relatively rare. SICS has developed a prototype tool for non-periodic timetabling that minimizes resource conflicts, enabling the user to focus on the strategic decisions. The prototype is called the Maraca and has been used and evaluated during the railway timetabling construction phase at the Swedish Transport Administration between April and September 2010.
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| 44. |
- Forsgren, Malin, et al.
(författare)
-
Tågtrafikplanering med successiv tilldelning
- 2009. - 5
-
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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| 45. |
- Gillblad, Daniel, et al.
(författare)
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Data Preparation in Complex Industrial Systems
- 2005. - 5
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Ingår i: Condition Monitoring and Diagnostic Engineering Management (COMADEM 2005). - Cranfield, UK : Cranfield University Press. - 1 871315 91 3 ; , s. 543-551
-
Konferensbidrag (refereegranskat)
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| 46. |
- Gillblad, Daniel, et al.
(författare)
-
Preparation and analysis of multiple source industrial process data
- 2005. - 1
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Industrial process data is often stored in a wide variety of formats and in several different repositories. Efficient methodologies and tools for data preparation and merging are critical for efficient analysis of such data. Experience shows that data analysis projects involving industrial data often spend the major part of their effort on these tasks, leaving little room for model development and generating applications. This paper identifies and classifies the needs and individual steps in data preparation of industrial data. A methodology for data preparation specifically suited for the domain is proposed and a practically useful set of primitive operations to support the methodology is defined. Finally, a proof of concept data preparation system implementing the proposed operations and a scripting facility to support the iterations in the methodology is presented along with a discussion of necessary and desirable properties of such a tool.
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| 47. |
- Gillblad, Daniel, et al.
(författare)
-
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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| 48. |
- Görnerup, Olof, et al.
(författare)
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Autonomous accident monitoring using cellular network data
- 2013
-
Ingår i: ISCRAM 2013 Conference Proceedings - 10th International Conference on Information Systems for Crisis Response and Management. - : Karlsruher Institut fur Technologie (KIT). - 9783923704804 ; , s. 638-646
-
Konferensbidrag (refereegranskat)abstract
- Mobile communication networks constitute large-scale sensor networks that generate huge amounts of data that can be refined into collective mobility patterns. In this paper we propose a method for using these patterns to autonomously monitor and detect accidents and other critical events. The approach is to identify a measure that is approximately time-invariant on short time-scales under regular conditions, estimate the short and long-term dynamics of this measure using Bayesian inference, and identify sudden shifts in mobility patterns by monitoring the divergence between the short and long-term estimates. By estimating long-term dynamics, the method is also able to adapt to long-term trends in data. As a proof-of-concept, we apply this approach in a vehicular traffic scenario, where we demonstrate that the method can detect traffic accidents and distinguish these from regular events, such as traffic congestions.
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| 49. |
- Holmborn, Katarina, et al.
(författare)
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On the Roles and Regulation of Chondroitin Sulfate and Heparan Sulfate in Zebrafish Pharyngeal Cartilage Morphogenesis
- 2012
-
Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287:40, s. 33905-33916
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Tidskriftsartikel (refereegranskat)abstract
- The present study addresses the roles of heparan sulfate (HS) proteoglycans and chondroitin sulfate (CS) proteoglycans in the development of zebrafish pharyngeal cartilage structures. uxs1 and b3gat3 mutants, predicted to have impaired biosynthesis of both HS and CS because of defective formation of the common proteoglycan linkage tetrasaccharide were analyzed along with ext2 and extl3 mutants, predicted to have defective HS polymerization. Notably, the effects on HS and CS biosynthesis in the respective mutant strains were shown to differ from what had been hypothesized. In uxs1 and b3gat3 mutant larvae, biosynthesis of CS was shown to be virtually abolished, whereas these mutants still were capable of synthesizing 50% of the HS produced in control larvae. extl3 and ext2 mutants on the other hand were shown to synthesize reduced amounts of hypersulfated HS. Further, extl3 mutants produced higher levels of CS than control larvae, whereas morpholino-mediated suppression of csgalnact1/csgalnact2 resulted in increased HS biosynthesis. Thus, the balance of the Extl3 and Csgalnact1/Csgalnact2 proteins influences the HS/CS ratio. A characterization of the pharyngeal cartilage element morphologies in the single mutant strains, as well as in ext2;uxs1 double mutants, was conducted. A correlation between HS and CS production and phenotypes was found, such that impaired HS biosynthesis was shown to affect chondrocyte intercalation, whereas impaired CS biosynthesis inhibited formation of the extracellular matrix surrounding chondrocytes.
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| 50. |
- 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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