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  • 151. Förstberg, Johan
    et al.
    Kottenhoff, Karl
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Olsson, Camilla
    Visst skakar det – men vad märker tågresenärerna?2004Report (Other academic)
  • 152.
    Gidofalvi, Gyözö
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Moran, Carlos
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Estimating Traffic Performance in Road Networks from Anonymized GPS Vehicle Probes2010In: Proceedings of the Workshop on Movement Research: Are you in the flow?: The 13th AGILE International Conference on Geographic Information Science, 10-14 May 2010, Guimarães, Portugal, 2010, p. 2-Conference paper (Other academic)
  • 153. Gordon, Jason B.
    et al.
    Koutsopoulos, Harilaos N.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Wilson, Nigel H. M.
    Attanucci, John P.
    Automated Inference of Linked Transit Journeys in London Using Fare-Transaction and Vehicle Location Data2013In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, no 2343, p. 17-24Article in journal (Refereed)
    Abstract [en]

    Urban public transit providers historically have planned and managed their networks and services with little knowledge of their customers' travel patterns. Although ticket gates and bus fareboxes yield counts of passenger activity in specific stations or vehicles, the relationships between these transactions-the origins, transfers, and destinations of individual passengers-typically have been acquired only through small, costly, and infrequent rider surveys. New methods for inferring the journeys of all riders on a large public transit network have been built on recent work into the use of automated fare collection and vehicle location systems for analysis of passenger behavior. Complete daily sets of data from London's Oyster farecard and the iBus vehicle location system were used to infer boarding and alighting times and locations for individual bus passengers and to infer transfers between passenger trips of various public modes, and origin-destination matrices of linked intermodal transit journeys that include the estimated flows of passengers not using farecards were constructed. The outputs were validated against surveys and traditional origin-destination matrices. The software implementation demonstrated that the procedure is efficient enough to be performed daily, allowing transit providers to observe travel behavior on all services at all times.

  • 154.
    Granath, Christian
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Införande av spårvägar i Örebro - Förslag till spårvägssträckning2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In Örebro, the car traffic share does not tend to decrease. The crowdedness on some of the bus routes is high at times. Investigations show that the residents of Örebro want a city centre whose street environment is more restrictive of car traffic and better for pedestrians, cyclists and public transport. To decrease the car traffic share a rapid, convenient, clear, effective and environmental friendly public transport with high frequency and strong capacity in a short, direct and logical network is needed. A modern tramway fulfils these criteria.

    At first, this report describes factors that are important to take into consideration when planning a tramway. Thereafter it comes with – from analysis of, among other things, the population density and travel pattern – suggestions for tramway routes through Örebro. Where more than one conceivable route alternative has been identified, comparisons have been made to illustrate their pros and cons. A big part of the work has been devoted to – after considering the physical condition of the street space – showing problems and possibilities, and coming up with proposals for the design.

    These are some of the conclusions made by the report (-gatan = the… street, -vägen = the… road):

     A good starting point would be "tramwayfication" of the bus routes 1 to 4 and their wickerwork structure.

     To avoid a big demand of complementing bus service the mean value of the tramways stop spacing in Örebro should not be bigger than 700 meters.

     To give Vivalla an effective and attractive tramway it has to go straight through the area.

     A route that goes via the Hedgatan/Kryptongatan intersection, between Baronbackarna and Vivalla centre, would be better than a route passing next to the Vivalla school. This is dependent, however, on new buildings being concentrated to the Vivalla/Lundby passage and the development of Vallby into no more than a low-density residential area.

     A route along Malmgatan and Järnvägsgatan would be better than a route along Västra Nobelgatan and Östra Nobelgatan or Kilsgatan and Olaigatan.

     Hedgatan between Långgatan and Trängkårsvägen, Västra Nobelgatan between Västerplan and Hertig Karls Allé (including the intersection Västra Nobelgatan/Hertig Karls Allé), Västra Nobelgatan between Lövstagatan and Gustavsgatan, Rudbecksgatan between Trädgårds-gatan and Mogatan, and Åstadalsvägen between Rundstigen and Barkvägen are places that can be tricky when it comes to the construction of a tramway and therefore require specific solutions.

     For streets that could be subject to a future tramway, it would be more efficient and more cost effective to adjust the physical environment of the street – the sewage and drainage systems, for example – at the same time as any pre planned routine maintenance.

     The housing areas along the current public transport passages should be made more concentrated; especially on those streets which could be subjected to a future tramway.

     New constructions that could make the conditions worse for a future tramway should not be started. For example, the parking area in front of the main entrance to the hospital (USÖ) and the area immediately south of the roundabout next to the university should not be built on before plans for a future tramway have been finalised.

     

  • 155. Grumert, Ellen
    et al.
    Ma, Xiaoliang
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Tapani, Andreas
    Effects of a Cooperative Variable Speed Limit System on Traffic Performance and Exhaust Emissions2013In: TRB 92nd Annual Meeting Compendium of Papers, 2013Conference paper (Refereed)
    Abstract [en]

    Variable Speed Limit Systems (VSLS) where variable message signs show speed limits based on traffic or road conditions exist on motorways in many countries. The purpose of the VSLS is to decrease the number of accidents while increasing efficiency of traffic system. Cooperative systems are a type of intelligent transport system that has received increasing interest lately. The central part of a cooperative system is communication between vehicles and/or vehicles and the infrastructure. In this paper, a cooperative systems extension of a VSLS is proposed and evaluated by means of microscopic traffic simulation. In the proposed cooperative VSLS, communication between the vehicles and the infrastructure is made available via a roadside unit communicating the speed limits to vehicles upstream on the road. Both aggregate and micro-scale emission models are used to estimate emission from vehicle states in traffic flow. The results of the study show that the cooperative VSLS has a potential to contribute to flow harmonization and to reduce environmental impacts. The emission estimates in the study are dependent on the emission models being applied.

  • 156.
    Gröndahl, Thérèse
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    High capacity transports.: Fallstudier: Ekonomiska och miljömässiga jämförelser mellan HCT, konventionell lastbil och järnväg.2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of Sweden’s national climate targets is to lower the greenhouse gas emissions from the transport sector by 40 % between 1990 and 2020. To meet the demand of increasing amount of transports and to fulfill the climate targets, the effects of longer and heavier trucks are being tested and evaluated. High Capacity Transports (HCT) means that the vehicles’ length and/or gross weight are allowed to increase so that each vehicle can transport more freight. The objectives are that HCT should contribute to lower transport costs, lower environmental effects, increased traffic safety, and less road wear with decreased maintenance. There are some concerns regarding HCT though, that it will affect other transport modes negatively. The main concern is that freight will be transferred from railway to truck.

    This master thesis examines the potential of HCT on roads and compares the advantages and disadvantages of HCT with railway. A literature review describes the development of trucks in Sweden until today and hypothetical effects of HCT in the road system as well as in the transport system as a whole, focusing on the railway market. Interviews with authority and company representatives have been performed.

    The thesis is focused on environmental aspects and transport economy. To enable an evaluation of HCT regarding these aspects and to be able to compare HCT with other transport alternatives, calculation schemes for transport costs and carbon emissions have been created. Comparisons between traditional truck, HCT, direct railway transport, and intermodal transport with truck and rail can be made with the calculation schemes. The calculation schemes have been applied to two case studies. Case study 1, Ett Coil Till, is a pilot project with HCT between Sölvesborg harbor and Olofström, in Blekinge. Trucks of 30 % higher gross weight than traditional trucks are tested on a distance of 34.5 km. Comparisons of three scenarios have been made in this case; truck transport of today, HCT, and transport on railway (hypothetical

    alternative). Case study 2 examines the pilot project called Duo

    2between Gothenburg and Malmö, a distance of 300 km. The calculation schemes compare traditional truck

    transport (tractor + trailer), HCT (tractor + two trailers) and intermodal transport with trailers. The calculation schemes are not exact, but work as a simple analysis tool that

    can be used in an early stage of evaluation of HCT.

    Results of case study 1:

    HCT would lower the total transport cost for road transport with 14 %.

    Carbon emissions would decrease with 17 % with HCT.

    The number of heavy transports would decrease with 23 %.

    Results of case study 2:

    HCT would lower the total transport cost for road transport with 37 %.

    Carbon emissions would decrease by 28 % with HCT.

    The number of heavy transports would decrease with 50 %.

    The calculations also show that railway freight transport is far more environmental friendly and often has lower total transport costs than truck transport. However, the railway has difficulties to compete with the truck due to high capital expenditures, low flexibility, and lacking quality (e.g. in terms of time). The results of the

     

     

     

    6  

     

    calculations show that HCT may increase the competition between truck and railway through decreased transport costs for HCT. The probability that more customers in the future will choose truck rather than railway will consequently increase, since the cost appear to be the most significant factor for the customers’ choice of transport mode.

    From the perspective of the road system: Regarding the results of the calculations and with the concept of co-modality in mind, as well as reports showing that transfer of freight from railway to truck is limited, HCT appears to be an alternative worth developing.

  • 157.
    Gunnäs, Pontus
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Organization of regional rail public transport.: An integrated system is important if we want to increase the public transport share.2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Public transport shows large regional disparities in development. This report aims to

    determine if any part of the cause is to be found in the form of the regional public transport

    organizations. There is no doubt about the eager for increasing the public transport market

    share beyond societal basic principle where the public transport covers school and work

    commuting in order to be an environmentally friendly substitute for the car. The amount of

    money spent on public transport and the idea of an integrated system differs from region to

    region, what seems to be the optimal way of creating a regional transportation to increase

    the public transport market share?

    The population is getting bigger and bigger and this fact contributes to regional growth

    round cities in Sweden. To fulfill necessary needs regarding transportation for these people

    living in the outer part of a region, counties are working together to simplify the travel.

    What's making this work difficult is that every county has their own prices for purchasing

    monthly passes to access the public transport, and since these passes aren’t valid for

    journeys across the county border, this limits the regional growth. In addition to this fact

    that counties have to erase the difficulties with handling different situations within each

    county, the public transport has been since the year 2012 deregulated in Sweden and the

    market is open for any transport company to start a business. Many companies in the same

    area also create a confusing situation for the travelers regarding the needs for different

    tickets for different part of the same journey. If a traveler misses the intended departure it is

    not certain that she can take the next departure if this is provided by another company. All

    together create county borders, many companies, increasing need for regional growth and

    travel together with a severe economic situation the foundation for this investigation.

    The report is conducted by studying reports, books and other available information such as

    the traffic development program from each county. This information is compared with a

    model with statistics from each region and at least one representative in the form of an

    experienced employee from the public transport sector in each region. This data and analysis

    work as the foundation for the results in this thesis.

  • 158.
    Gunnäs, Pontus
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Prioriteringen av tågtrafiken på järnvägen.2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Att tåg samsas om samma järnväg är kanske ingen nyhet, men varför järnvägsföretagen måste

    samarbeta dagligen, både med varandra och Trafikverket, för att få trafiken att gå ihop är det inte alla som känner till. När ett tåg är försenat får detta konsekvenser, inte bara för resenärerna ombord som kommer fram efter uttalad ankomsttid, utan även för de andra tåg som trafikerar samma sträcka. Beroende på hur många spår den aktuella sträckan har går det olika lätt för två eller flera tåg att mötas. Den stora frågan som var utgångspunkten för detta arbete var vilket av alla berörda tåg som ska få åka när. Vem bestämmer vilket tåg som får gå i bästa rusningstiden? Och vilket tåg får prioritet vid en eventuell konflikt?

    Oavsett om du som läser detta arbete arbetar inom järnväg, är en van resenär eller om du inte ens har åkt tåg en gång är det ovanligt att man förstår komplexiteten i järnvägstrafik. Detta arbete vill belysa bakgrunden till varför järnvägsföretagen och Trafikverket måste prioritera tåg på järnvägen idag. Det handlar om att järnvägskapaciteten är utnyttjad på ett sådant sätt att förseningar kan vara förödande för punktligheten på en mängd olika tåg trots att det bara var ett tåg som var försenat från början.

    Järnvägstrafiken och infrastrukturen som sådan förändras. Idag ser det inte likadant ut som det

    gjorde när morfar åkte tåg för femtio år sedan "då inga tåg var försenade". Idag har trafiken ökat

    markant på järnvägen, och monopolet är släppt. Det sistnämnda innebär att det idag finns ett flertal olika aktörer på spåren som alla vill att just deras tåg ska få den bästa avgångstiden och ha prioritet i eventuella konflikter.

    Bakgrunden till problemet är kort sagt att det järnvägsnätet inte kan mätta behovet från alla tågoperatörer som vill köra tåg idag samt att det inte finns en bra lösning på vilket tåg som ska få företräde i en konflikt när dessa uppstår på järnvägen idag. Det arbetas utifrån fall till fall och resultatet understryker skillnaden mellan erfarenheten hos personen som tar detta beslut.

    Under hela året ansöker tågoperatörerna om tåglägen hos Trafikverket inför nästa års tidtabell. Trafikverket har i uppgift att prioritera mellan dessa och fördela ut tåglägen så att trafikdygnet är så välutnyttjat som möjligt. Så länge ett tåg håller sig i sin tidtabell kallas det att tåget håller sig i sin kanal. Så länge alla tåg håller sig i sin kanal finns därmed inga förseningar och konflikterna kommer antingen att undvikas eller att inträffa på planerade mötesstationer.

    När det handlar om operativa konflikter som uppstår när ett eller flera tåg är försenade finns det en övergripande regel på järnvägen att rättidigt tåg ska prioriteras. Denna har uppkommit som en följd av att tågtrafiken har ökat kraftigt under de senaste åren och tåg anses få för svårt att köra in tid vid en eventuell försening på järnvägen idag.

    Målet med arbetet är att lyfta fram dagen prioriteringsproblematik som existerar på järnvägen. Att ge en djupare förståelse för hur komplex järnvägstrafik är, genom att beskriva situationer där olika beslut får väldigt olika utfall. Arbetet baseras mycket på intervjukällor som på ett eller annat sätt är insatta i järnvägsbranschen.

  • 159.
    Habibi, Shiva
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    A discrete choice model of transport chain and shipment size on Swedish commodity flow survey 2004/20052010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Freight demand models have not been developed that much as passenger demand models. The

    reason is existence of too many complexities in this area. To estimate a disaggregate freight

    transport models large input data is required. The Swedish Flow Commodity survey 2004/2005

    (CFS) which is a unique data source at the level of individual firms made it possible to estimate a

    disaggregate model to analyze the choice of transport chains and shipment size for the domestic

    metal products. The output of logistics module of the Swedish national freight transport

    (SAMGODS) is used as an auxiliary database to incorporate logistics decisions which CFS lacks

    in the model.

    The model comprises logistics perspective by considering both shipment size and transport

    chains as endogenous choices. Characteristics of shippers, shipments and transport chains are

    included in the model to analyze the choice of transport chain and shipment size. It has been

    tried to include as many transport chains as possible in the choice sets to consider their effects on

    decision making. Transport costs have been included in the model as shipment size specific to

    incorporate the concept of logistics more precisely in the model.

    From the results it can be seen that the freight transport demand is almost inelastic to the cost.

    The model gives a positive sign for the coefficient of the transport time which can be explained

    as the storage cost is so high that shippers prefer to use transport modes as the moving

    inventories instead.

    Finally, it is suggested to estimate panel discrete choice models on this dataset.

     

  • 160.
    Hlotova, Yevheniia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Cats, Oded
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. Delft Univ Technol, Dept Transport & Planning, Netherlands.
    Meijer, Sebastiaan
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. Delft Univ Technol, Fac Technol Policy & Management, Netherlands.
    Measuring Bus Drivers' Occupational Stress Under Changing Working Conditions2014In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, no 2415, p. 13-20Article in journal (Refereed)
    Abstract [en]

    Stress is an immense problem in modern society; approximately half of all occupational illnesses are directly or indirectly related to stress. The work of a bus driver is typically associated with high stress levels that negatively influence individual well-being as well as workforce management. The current study examined the impact of newly proposed working conditions on bus drivers' occupational stress by monitoring heart rate and by collecting data on mental workload with a questionnaire in operational driving conditions. The main determinants of stress levels were identified through multiple regression analysis. Results indicated that bus drivers experienced considerably lower stress levels under a new control strategy that shifts the performance objective from schedule adherence to service regularity. Higher stress levels were recorded during extreme weather conditions and peak hours and among inexperienced drivers. The measurements were performed with low-cost sports devices that can easily be used by practitioners.

  • 161.
    Hofstede, Gert Jan
    et al.
    Logistics, Decisions and Informatics, Wageningen University.
    Kramer, Mark
    Wageningen University.
    Meijer, Sebastiaan
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Wijdemans, Jeroen
    Information Technology, Wageningen University.
    A Chain Game for distributed trading and negotiation2001In: Experimental Learning in Industrial Management: Transference & Creation of Knowledge: 6th International Workshop on Simulation Gaming in Production Management / [ed] Juan Cano, Zaragoza University , 2001Conference paper (Refereed)
  • 162.
    Huang, Zhen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Ma, Xiaoliang
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Koutsopoulos, Haris
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    A numerical optimization approach for calibration of dynamic emission models based on aggregate estimation of ARTEMIS2010In: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, 2010, p. 1221-1226Conference paper (Refereed)
    Abstract [en]

    In this paper, we propose a numerical approach to calibrate dynamic emission models when on-road or in-lab instantaneous emission measurements are not fully available. Microscopic traffic simulation is applied to generate dynamic vehicle states in the second-by-second level. Using aggregate estimation of ARTEMIS as a standard reference, a numerical optimization scheme on the basis of a stochastic gradient approximation algorithm is applied to find optimal parameters for the dynamic emission model. The calibrated model has been validated on several road networks with traffic states generated by the same simulation model. The results show that with proper formulation of the optimization objective function the estimated dynamic emission model can reasonably capture the trends of online emissions of traffic fleets.

  • 163. Huibregtse, Olga
    et al.
    Flötteröd, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Bierlaire, Michel
    Hegyi, Andreas
    Hoogendoorn, Serge
    A fixed-point approach to system-optimal route advice considering compliance behavior2012In: Proceedings of the Annual Meeting of the Transportation Research Board, Washington DC, USA, 2012Conference paper (Refereed)
  • 164.
    Ibanez Usach, Rafael
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Evaluation of route alternatives for a new railway by-pass through the west of Stockholm from an accessibility perspective.2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 165. Illenberger, J.
    et al.
    Flötteröd, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Estimating network properties from snowball sampled data2012In: Social Networks, ISSN 0378-8733, E-ISSN 1879-2111, Vol. 34, no 4, p. 701-711Article in journal (Refereed)
    Abstract [en]

    This article addresses the estimation of topological network parameters from data obtained with a snowball sampling design. An approximate expression for the probability of a vertex to be included in the sample is derived. Based on this sampling distribution, estimators for the mean degree, the degree correlation, and the clustering coefficient are proposed. The performance of these estimators and their sensitivity with respect to the response rate are validated through Monte Carlo simulations on several test networks. Our approach has no complex computational requirements and is straightforward to apply to real-world survey data. In a snowball sample design, each respondent is typically enquired only once. Different from the widely used estimator for Respondent-Driven Sampling (RDS), which assumes sampling with replacement, the proposed approach relies on sampling without replacement and is thus also applicable for large sample fractions. From the simulation experiments, we conclude that the estimation quality decreases with increasing variance of the network degree distribution. Yet, if the degree distribution is not to broad, our approach results in good estimates for the mean degree and the clustering coefficient, which, moreover, are almost independent from the response rate. The estimates for the degree correlation are of moderated quality.

  • 166. Illenberger, Johannes
    et al.
    Flötteröd, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Estimating properties from snowball sampled networks2011Report (Other academic)
  • 167. Illenberger, Johannes
    et al.
    Flötteröd, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Kowald, Matthias
    Nagel, Kai
    A model for spatially embedded social networks2009In: Proceedings of the 12th International Conference on Travel Behaviour Research, Jaipur, India, 2009Conference paper (Refereed)
  • 168. Illenberger, Johannes
    et al.
    Flötteröd, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Nagel, Kai
    Enhancing MATSim with capabilities of within-day re-planning2007In: Proceedings of the 10th IEEE Intelligent Transportation Systems Conference, Seattle, USA, 2007Conference paper (Refereed)
  • 169. Illenberger, Johannes
    et al.
    Flötteröd, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Nagel, Kai
    The role of spatial interaction in social networks2011Report (Other academic)
  • 170. Illenberger, Johannes
    et al.
    Nagel, Kai
    Flötterod, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    The Role of Spatial Interaction in Social Networks2013In: Networks and Spatial Economics, ISSN 1566-113X, E-ISSN 1572-9427, Vol. 13, no 3, p. 255-282Article in journal (Refereed)
    Abstract [en]

    This article addresses the role of spatial interaction in social networks. We analyse empirical data describing a network of leisure contacts and show that the probability to accept a person as a contact scales in distance with similar to d (-aEuro parts per thousand 1.4). Moreover, the analysis reveals that the number of contacts an individual possesses is independent from its spatial location and the spatial distribution of opportunities. This means that individuals living in areas with a low accessibility to other persons (rural areas) exhibit at average the same number of contacts compared to individuals living in areas with high accessibility (urban areas). Low accessibility is thus compensated with a higher background probability to accept other candidates as social contacts. In addition, we propose a model for large-scale social networks involving a spatial and social interaction between individuals. Simulation studies are conducted using a synthetic population based on census data as input. The results show that the model is capable of reproducing the spatial structure, but, however, fails to reproduce other topological characteristics. Both, the analysis of empirical data and the simulation results provide a further evidence that spatial interaction is a crucial aspect of social networks. Yet, it appears that spatial proximity does only explain the spatial structure of a network but has no significant impact on its topology.

  • 171.
    Jansson, Emil
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Utredning av stadslinjenätet i Norrtälje.2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Norrtälje är en utpräglad pendlarstad med 18000 invånare och som ligger 70 km norr om Stockholm. Staden har i dagsläget fyra stycken stadslinjer som är tillgängliga för i stort hela tätortens invånare. Stadslinjenätet har förändrats flera gånger de senaste åren, från att enbart ha bestått av ringlinjer 2006 har dessa nu brutits upp och i dagsläget består nu av enbart dubbelriktade linjer. Då staden helt saknar spårtrafik sker all pendling till Stockholm med buss och huvudlinjen är stombusslinjen 676 med mycket hög turtäthet.

    Syftet med detta arbete har varit att hitta brister i stadslinjenätet och utifrån dessa brister komma med förslag på förändringar. Metoderna som använts har varit att gå igenom tidtabeller, göra fältstudier och undersökningar samt att analysera resestatistik.

    I jämförelse med andra liknande städer står sig Norrtälje mycket bra både vad gäller turtäthet och trafikeringstid. Det enda som Norrtälje kan lära av de undersökta städerna är att presentera stadslinjerna på ett tydligare sätt, att linjerna får sammanhängande nummer och en karta som enbart visar stadslinjerna.

    Det gjordes en reseundersökning vid en infartsparkering i Norrtälje för att ta reda på anledningen till att människor väljer att ta bilen istället för att åka kollektivt. Resenärerna fick svara på om de bodde i eller utanför Norrtälje och vad den främsta anledningen var till att de inte åkte kollektivt hela vägen. Resultatet visade att ca 30 % bodde i Norrtälje och hälften av dessa angav att de var beroande av bilen för att hämta eller lämna på förskola, hunddagis eller skola. Detta kan göra det svårt att få dessa resenärer att resa kollektivt hela vägen.

    Den tydligaste bristen som upptäcktes i stadstrafiknätet var den dåliga anslutningen mellan stadslinjerna och 676. Detta hade sin naturliga förklaring i att 676s tidtabell är oregelbunden vilket gör det väldigt svårt att få passning till den. För att få till en bra passning behöver även stadstidtabellerna ha en oregelbunden tidtabell och dessutom behöver vissa områden prioriteras. Denna prioritering baserades på nulägesbeskrivingen och analysen av nätet, de områden som kom att prioriteras var Grind, Solbacka och Vigelsjö som ligger längst bort från 676s hållplatser och har störst befolkning.

    Under fältstudierna uppkom även några idéer till nya hållplatser och dessa skulle kunna höja kvalitén på busstrafiken i Norrtälje genom att öka tillgängligheten och attraktivheten. Genom att anlägga en hållplats i nordlig riktning vid Norrtälje sjukhus skulle tillgängligheten öka vid denna samhällsviktiga plats och genom att låta stadsbussarna passera vid Gamla stationsplan skulle stadstrafiken komma närmare stadens centrum.

    Slutligen gjordes ett tidtabellsförslag för linjerna 656, 657 och 658 och med detta förslag har bytestiderna förbättrats i första hand för de prioriterade områden men även för hela Norrtälje. Dessa tidtabellsförslag finns med som en bilaga.

  • 172.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Data fusion of instantaneous speeds and point-to-point travel times from probe vehicle data2013Conference paper (Refereed)
  • 173.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Transport and Location Analysis (closed 20110301). KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Network structure and travel patterns: explaining the geographical disparities of road network vulnerability2009In: Journal of Transport Geography, ISSN 0966-6923, E-ISSN 1873-1236, Vol. 17, no 3, p. 234-244Article in journal (Refereed)
    Abstract [en]

    Inevitably, links in the road network are sometimes disrupted because of adverse weather, technical failures or major accidents. Link closures may have different economic and societal consequences depending on in which regions they occur (regional importance), and users may be affected differently depending on where they travel (regional exposure). In this paper we investigate in what way these geographical disparities depend on the road network structure and travel patterns. We propose aggregate supply-side (link redundancy, network scale, road density, population density) and demand-side (user travel time, traffic load) indicators and combine them in statistical regression models. Using the Swedish road network as a case study, we find that regional importance is largely determined by the network structure and the average traffic load in the region, whereas regional exposure is largely determined by the network structure and the average user travel time. Our findings show that the long-term vulnerability disparities stem from fundamental properties of the transport system and the population densities. Quantitatively, they show how vulnerability depends on different variables, which is of interest for robust network design.

  • 174.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Transport and Location Analysis (closed 20110301). KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Redundancy importance: Links as rerouting alternatives during road network disruptions2010In: Procedia Engineering, 2010, Vol. 3, p. 129-137Conference paper (Refereed)
    Abstract [en]

    We consider the importance of road links as backup alternatives when other links in the network are disrupted (due to events such as floods, landslides, car accidents etc.). While traditional measures of link importance capture a link’s role for transport efficiency under normal conditions, we are interested in a link’s role for transport robustness and network redundancy. We refer to this concept as redundancy importance and introduce two measures based on traffic flow and disruption impacts (here operationalized as travel delay), respectively. In the flow-based measure we consider the net traffic flow that is redirected to the studied link when other links are closed. In the impact-based measure we also consider the impact that is avoided through the studied link, i.e., how much worse the next-best backup alternatives would be if the studied link itself would not be available. We argue that although a link may not be important under normal conditions, a higher prioritization in resource allocations could be justified if many users could come to rely on it in extraordinary situations. Hence, these measures should be useful as quantitative decision support in the allocation of resources for investments and maintenance as well as for setting up pre-emptive rerouting plans. The measures are applied in a case study of northern Sweden and the general characteristics that determine which links are redundancy important are identified.

  • 175.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    The value of travel time variability with trip chains, flexible scheduling and correlated travel times2012In: Transportation Research Part B: Methodological, ISSN 0191-2615, E-ISSN 1879-2367, Vol. 46, no 6, p. 762-780Article in journal (Refereed)
    Abstract [en]

    This paper extends the analysis of the value of mean travel time (VMTT) and day-to-day travel time variability (VTTV) from single, isolated trips to daily trip chains, considering the effects of flexibility in activity scheduling and within-day correlation of travel times. Using a multi-stage stochastic programming approach, we show that the VMTT and VTTV on a trip is conditional on the realized travel times on preceding trips, first through the arrival time to the preceding activity and second through the information provided about subsequent travel times. Analytical formulas for the VMTT and VTTV are obtained for two special cases with piecewise constant and linear marginal cost functions, respectively. With flexible scheduling, there is typically a cost associated with a positive correlation of travel times, arising from persistent deviations from typical travel demand or supply on a given day. However, there is also a strict benefit in the dependence since it allows for a more efficient scheduling of later trips.

  • 176.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Vilka regioner är mest sårbara för avbrott i vägnätet och varför?2010Conference paper (Other academic)
  • 177.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Koutsopoulos, Haris
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Consistent travel time estimation using sparse probe vehicle data sampled by time and distance2012Report (Other academic)
  • 178.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Koutsopoulos, Haris
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Time-based vs. distance-based sampling in probe vehicle data: Implications for travel time estimation2012In: Proceedings of 17th International Conference of Hong Kong Society for Transportation Studies, Hong Kong, 2012Conference paper (Refereed)
    Abstract [en]

    This paper analyses the role of the sampling protocol for travel time estimation with low frequency probe vehicle data by likelihood-based methods, such as maximum likelihood or Bayesian estimation. In the literature, there are reported cases where the vehicle positions are sampled at either certain time intervals, say, every minute, or at certain distance intervals, say, every 500 meters. We show that whether sampling is distance-based or time-based determines the proper formulation of the likelihood function. Furthermore, an incorrect likelihood formulation (for example, treating sampling as distance-based when it is time-based in actuality) often leads to biased parameter estimates. For the special case in which the path is partitioned into segments with constant, independent travel speeds we derive explicit formulas for the likelihood function for each of the two sampling principles. We also study the consistency and bias of the estimators in numerical experiments. 

  • 179.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Koutsopoulos, Haris N.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Travel time estimation for urban road networks using low frequency probe vehicle data2013In: Transportation Research Part B: Methodological, ISSN 0191-2615, E-ISSN 1879-2367, Vol. 53, p. 64-81Article in journal (Refereed)
    Abstract [en]

    The paper presents a statistical model for urban road network travel time estimation using vehicle trajectories obtained from low frequency GPS probes as observations, where the vehicles typically cover multiple network links between reports. The network model separates trip travel times into link travel times and intersection delays and allows correlation between travel times on different network links based on a spatial moving average (SMA) structure. The observation model presents a way to estimate the parameters of the network model, including the correlation structure, through low frequency sampling of vehicle traces. Link-specific effects are combined with link attributes (speed limit, functional class, etc.) and trip conditions (day of week, season, weather, etc.) as explanatory variables. The approach captures the underlying factors behind spatial and temporal variations in speeds, which is useful for traffic management, planning and forecasting. The model is estimated using maximum likelihood. The model is applied in a case study for the network of Stockholm, Sweden. Link attributes and trip conditions (including recent snowfall) have significant effects on travel times and there is significant positive correlation between segments. The case study highlights the potential of using sparse probe vehicle data for monitoring the performance of the urban transport system.

  • 180.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Developing a methodology for road network vulnerability analysis2006Conference paper (Refereed)
  • 181.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Road network vulnerability analysis: Conceptualization, implementation and application2015In: Computers, Environment and Urban Systems, ISSN 0198-9715, E-ISSN 1873-7587, Vol. 49, p. 136-147Article in journal (Refereed)
    Abstract [en]

    The paper describes a process for road network vulnerability analysis, from (i) the conceptual definition of vulnerability measures, through (ii) the derivation of practical indicators and models adapted to available data and their implementation in computational procedures, to (iii) the application of the methodology in case studies. In the first step, the vulnerability concept is defined and quantified formally, and distinct user and technological perspectives are highlighted. In the second step, the conceptual measures are adapted and calculated according to the conditions, requirements and goals of a particular analysis. The paper describes practical indicators and algorithms developed for large-scale vulnerability analyses. For the third step, the paper analyzes both single link closures and area-covering disruptions and the distribution of impacts among different regions in a case study on the Swedish road transport system. The spatial patterns are put in connection with the regional variations in location and travel patterns and network density. Finally, the implications for policy and possible approaches to vulnerability management are discussed.

  • 182.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Road network vulnerability analysis of area-covering disruptions: A grid-based approach with case study2010Report (Other academic)
  • 183.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Road network vulnerability analysis of area-covering disruptions: A grid-based approach with case study2012In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 46, no 5, p. 746-760Article in journal (Refereed)
    Abstract [en]

    We present an approach to systematically analysing the vulnerability of road networks under disruptions covering extended areas. Since various kinds of events including floods, heavy snowfall, storms and wildfires can cause such spatially spread degradations, the analysis method is an important complement to the existing studies of single link failures. The methodology involves covering the study area with grids of uniformly shaped and sized cells, where each cell represents the extent of an event disrupting any intersecting links. We apply the approach to the Swedish road network using travel demand and network data from the Swedish national transport modelling system Sampers. The study shows that the impacts of area-covering disruptions are largely determined by the level of internal, outbound and inbound travel demand of the affected area itself. This is unlike single link failures, where the link flow and the redundancy in the surrounding network determine the impacts. As a result, the vulnerability to spatially spread events shows a markedly different geographical distribution. These findings, which should be universal for most road networks of similar scale, are important in the planning process of resource allocation for mitigation and recovery.

  • 184.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    The impact of network density, travel and location patterns on regional road network vulnerability2010Conference paper (Refereed)
  • 185.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Levinson, David
    Traveler delay costs and value of time with trip chains, flexible activity scheduling and information2010Report (Other academic)
  • 186.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Levinson, David
    Traveler delay costs and value of time with trip chains, flexible activity scheduling and information2011In: Transportation Research Part B: Methodological, ISSN 0191-2615, E-ISSN 1879-2367, Vol. 45, no 5, p. 789-807Article in journal (Refereed)
    Abstract [en]

    The delay costs of traffic disruptions and congestion and the value of travel time reliability are typically evaluated using single trip scheduling models, which treat the trip in isolation of previous and subsequent trips and activities. In practice, however, when activity scheduling to some extent is flexible, the impact of delay on one trip will depend on the actual and predicted travel time on itself as well as other trips, which is important to consider for long-lasting disturbances and when assessing the value of travel information. In this paper we extend the single trip approach into a two trips chain and activity scheduling model. Preferences are represented as marginal activity utility functions that take scheduling flexibility into account. We analytically derive trip timing optimality conditions, the value of travel time and schedule adjustments in response to travel time increases. We show how the single trip models are special cases of the present model and can be generalized to a setting with trip chains and flexible scheduling. We investigate numerically how the delay cost depends on the delay duration and its distribution on different trips during the day, the accuracy of delay prediction and travel information, and the scheduling flexibility of work hours. The extension of the model framework to more complex schedules is discussed.

  • 187.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Petersen, Tom
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Mattsson, Lars-Göran
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Road network vulnerability: Identifying important links and exposed regions2006Conference paper (Refereed)
  • 188.
    Jenelius, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Rahmani, Mahmood
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Koutsopoulos, Haris
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Travel time estimation for urban road networks using low frequency GPS probes2012Conference paper (Refereed)
  • 189.
    Jiang, Dian
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    The analysis of the impact between motor vehicles and pedestrians at signalized intersection.2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As more and more trips increase in the decades, the conflicts between the participants

    are more and more frequent. The main topic of the thesis is to study the impact of the

    conflicts: the impacts of conflicts between right turn motor vehicles and pedestrians at

    signalized intersection. The study focus the impacts on urban area. In these areas, the

    conflicts between pedestrians and motor vehicles are particularly distinct. The situation

    thesis describes is: most of the signalized intersections whose signal for right-turn

    vehicle and pedestrian going through are at the same phase, thus unavoidably causes a

    lot of conflicts between pedestrians and motor vehicles during that time, and it also

    brings about a great chance of accidents as well. The behavior of motor vehicles drivers

    and pedestrians highly affects the how they will be conflicted. In addition, the impacts

    could be different with different flow of motor vehicle and pedestrians. In this process,

    gap acceptance of the pedestrian weighs a lot. And two models are used here to analyze

    the conflict. One is from the Swedish Capacity Manual and the other is from HCM

    2010. In the thesis, a typical signalized intersection is chosen and the video are recorded

    to obtain data. The thesis discusses the differences of the two models, and some

    observed behaviors. And, according to the result, 500 pedestrian flow increase will

    bring 100 saturation flow rate decrease; and pedestrians flow at peak hour will increase

    travel time of motor vehicle over 100%. After that, some further studies and alternate

    methods are discussed.

  • 190. Johansson, Isabelle
    et al.
    Edner, Magnus
    Dahlström, Ulf
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Rydén, Lars
    Norhammar, Anna
    Is the prognosis in patients with diabetes and heart failure a matter of unsatisfactory management?: An observational study from the Swedish Heart Failure Registry2014In: European Journal of Heart Failure, ISSN 1388-9842, E-ISSN 1879-0844, Vol. 16, no 4, p. 409-418Article in journal (Refereed)
    Abstract [en]

    Aims To analyse the long-term outcome, risk factor panorama, and treatment pattern in patients with heart failure (HF) with and without type 2 diabetes (T2DM) from a daily healthcare perspective. Methods and results Patients with (n = 8809) and without (n = 27 465) T2DM included in the Swedish Heart Failure Registry (S-HFR) 2003-2011 due to a physician-based HF diagnosis were prospectively followed for long-term mortality (median follow-up time: 1.9 years, range 0-8.7 years). Left ventricular function expressed as EF did not differ between patients with and without T2DM. Survival was significantly shorter in patients with T2DM, who had a median survival time of 3.5 years compared with 4.6 years (P < 0.0001). In subjects with T2DM. unadjusted and adjusted odds ratios (ORs) for mortality were 1.37 [95% confidence interval (CI) 1.30-1.44) and 1.60 (95% CI 1.50-1.71), and T2DM predicted mortality in all age groups. Ischaemic heart disease was an important predictor for mortality (OR 1.68, 95% CI 1.47-1.94), more abundant in patients with T2DM (59% vs. 45%) among whom only 35% had been subjected to coronary angiography and 32% to revascularization. Evidence-based pharmacological HF treatment was somewhat more extensive in patients with T2DM. Conclusion The combination of T2DM and HF seriously compromises long-term prognosis. Ischaemic heart disease was identified as one major contributor; however, underutilization of available diagnostic and therapeutic facilities for ischaemic heart disease was obvious and may be an important area for future improvement in patients with T2DM and HF.

  • 191.
    Kasiri, Afsaneh
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    A Model for Travel Behavior of Employee in terms of Employee-based Trip Reduction in Sweden2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 192.
    Kazagli, Evanthia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science.
    Koutsopoulos, Haris N.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Estimation of Arterial Travel Time from Automatic Number Plate Recognition Data2013In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, no 2391, p. 22-31Article in journal (Refereed)
    Abstract [en]

    Automatic vehicle identification (AVI) systems are increasingly used for the collection of traffic data in urban and freeway networks. Several methods have been proposed for the estimation of travel times from AVI data, mainly for freeways. The problem of estimation of travel times in urban networks was examined. The main difference between freeway and urban networks is that urban network AVI data are often extremely noisy. A major part of that noise is attributed to vehicles that do not traverse the monitored section directly but stop for various reasons. A mixture model was proposed to capture the underlying states of the measurements of AVI travel times in urban areas. The hypothesis was that travel times are drawn from two (or more) populations, one representing normal movement through the network and one representing vehicles that stop for whatever reason. The method was applied with AVI data (collected through a system for automatic recognition of number plates) from a number of corridors in central Stockholm, Sweden. The model was estimated as a mixture-of two lognormal distributions, and bootstrap standard errors were calculated. The results illustrate the robustness of the method and its ability to identify the underlying distribution of the latent populations consistent with the characteristics of each route, while standard methods for outlier removal fail.

  • 193.
    Kindström, Patrik
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Marknadsanalys av ett svenskt transportsystem med höghastighetsgodståg.2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In Sweden plans to build high speed railways have been around since the early 1990s and the plans

    have developed to be more precised since. The future Swedish high-speed rail network is supposed

    to consist of two lines. Götalandsbanan; from Stockholm to Gothenburg, and Europabanan from

    Jönköping through the Öresund Region to Hamburg.

    The description of the aim to build high-speed railways in Sweden has in former reports always been

    to achieve rapid passenger traffic between big Scandinavian cities and Europe. There are almost

    nothing mentioned about the possibilities of high-speed transports of cargo on these railways. This

    study aims to clarify the freight transport market for Götalandsbanan and Europabanan.

    Today there is only one transport system with high-speed freight trains. It is the French Post, La

    Poste, trains for letter and parcel transportation. A more comprehensive system, called Euro Carex, is

    at the planning stage in Europe. The plan is to set up cargo terminals at some of Europe's largest

    cargo airports where transshipments between flight and rail can be made.

    Today train transport has a strong position in the bulk and base market. A transport system with

    high-speed freight trains attracts an entirely different type of cargo. There are two distinctive characteristics

    that make the goods possible to transport with high-speed trains. These are:

    High value

    Requirements for short transport time

    Such goods are for instance freight today transported by air freight over medium distances and truck

    transportations where the journey time is not satisfactory and where air freight is too costly. Products

    fulfilling those characteristics are for example, letters, packages, newspapers, flowers, special

    mechanical components and medical equipment.

    The key to be able to establish a transport system is the amount of goods that would be possible to

    transport with high-speed trains. In the current situation road haulage has the absolute majority of

    the transport market of highly processed goods with high value products. Air cargo accounts for only

    a tiny part, which is almost negligible in comparison with other transport modes. The service market

    in which letters and packages are included is however an expanding market, which means that

    freight volumes are likely to increase over time.

    In this study an analysis of the freight customers' preferences has been done as well as a circulation

    analysis for the train traffic, a cost analysis and a distance and travel time analysis.

    Realistic timetables for each train set have been created to serve as input for the cost analysis. The

    created timetables consist of traffic in following relationships:

    Stockholm

    Gothenburg

    Stockholm

    –Malmoe–

    Copenhagen

    Stockholm

    –Copenhagen–

    Hamburg

    8

    Two different scenarios have been developed in order to cover for uncertainty of the market size.

    One scenario with high vehicle utilization rate and another with less.

    The cost analysis for high-speed freight train traffic is made with a cost model developed for Gröna

    tåget by Oskar Fröidh. Four traffic models have been analyzed with varied parameter values. The

    traffic model characteristics and the cost analysis results are seen in the table below.

    Traffic

    Model

    Train Size Utilization Rate

    Train Traffic Cost

    (SEK/tonne-km)

    Total Cost incl.

    Terminal Costs

    (SEK/tonne-km)

    1

    Small, six railcars Low, scenario 1 1,30 2,30

    2

    Small, six railcars High, scenario 2 1,20 1,96

    3

    Large, eight railcars Low, scenario 1 1,27 2,02

    4

    Large, eight railcars High, scenario 2 1,16 1,73

    Table: The characteristics of the four analyzed traffic models and the resulting costs.

    Interviews have been done with companies that can be interested in using such a transport system

    on order to investigate the size of the market for a Swedish transport system with high-speed freight

    trains. Seven companies have been contacted of which four have responded. The amount of goods

    that could be transferred to high-speed freight train if such a system existed today is about 8 400

    tonnes per year. The amount corresponds to the identified goods that for sure would have been

    transferred. Cargo volumes for the different relations can be seen in the table below.

    Relation Godsmängd (ton/år)

    Stockholm - Göteborg

    2 900

    Stockholm - Malmö

    5 500

    Table: Identified freight volume possible to transport with high-speed freight trains.

    If the costs should be as calculated in the cost analysis a transport system with high-speed freight

    trains would require market of 196 000 tonnes of freight per year. A transport system consisting of

    only one train would require a market of about a third, which is approximately 65 000 tonnes. With

    such traffic pattern the cost would be significantly higher for transporting goods with high-speed

    freight trains than the calculated values. From these results the conclusion is that there is not a sufficient

    market for a transport system with high-speed freight trains in Sweden.

  • 194.
    Kordnejad, Behzad
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Intermodal Liner Freight Trains: Opportunities and Limitations2011Conference paper (Refereed)
  • 195.
    Kordnejad, Behzad
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Intermodal Transport Cost Model and Intermodal Distribution in Urban Freight2014In: Proceedings of the 8th International Conference on City Logistics, Elsevier, 2014Conference paper (Refereed)
    Abstract [en]

    This study aims to model a regional rail based intermodal transport system and to examine the feasibility of it through a case study for a shipper of daily consumables distributing in an urban area and to evaluate it regarding cost and emissions. The idea of an intermodal line train is that of making intermediate stops along the route thus enabling the coverage of a larger market area than conventional intermodal services, hence reducing the high cost associated with feeder transports, the congestion on the road network and generated externalities. The results of the case study indicate that the most critical parameters for the feasibility of such a system are the loading space utilization of the train and the cost for terminal handling.

  • 196.
    Kordnejad, Behzad
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Marknad för regional kombitrafik: En delrapport inom forskningsprojektet ”Regionalt kombitransportsystem i Mälardalen”2012Report (Other academic)
  • 197.
    Kordnejad, Behzad
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Regional Intermodal Transport Systems: Analysis and Case Study in the Stockholm-Mälaren Region2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The global trend of urbanization is evident and also valid in Sweden and for the Stockholm-Mälaren region, also referred to as the Mälaren valley, a region consisting of metropolitan Stockholm and areas around the lake of Mälaren. In this context, efficient urban freight transportation has emerged as essential for sustainable development of urban areas. Geographic regions are being expanded due to the fact that rapid transport options have expanded the range of action of people and businesses. Metropolitan regions require freight transports that are often categorized by an inflow of consumables and an outflow of waste and recyclable material. Within urban areas there are ports, terminals and storage facilities that require incoming and outgoing transport. Altogether, these shipments have led to increased congestion on the road network within urban areas, which is a contributing factor to why a shift to intermodal land transports have been advocated both in Europe and in Sweden, thus encouraging more freight to be moved from road to rail. Another contributing factor is the relatively low impact on the environment generated by rail transportation. Efficient use of resources and low emissions of greenhouse gases are factors that are in favor of the train as a transport mode.

    Furthermore, conventional rail freight is commonly competitive on long distances and in end-point relations between two nodes. However, an intermodal liner train, as a transport system for freight differs from conventional rail freight transport systems, as it similar to a passenger train makes stops along the route for loading and unloading. Due to the stops made at intermediate stations it enables the coverage of a larger market area. For regional or inter-regional relations, the concept has the potential of reducing drayage by truck to and from intermodal terminals and to make rail freight competitive also over medium and short distances.

    The main aim of this thesis project has been to analyze under which conditions a combined transport system with the railway as a base can be implemented in the Stockholm-Mälaren region. Based on a case study for a shipper distributing daily consumables in the region, the feasibility of creating a regional rail freight transport system has been evaluated.

    This study provides a methodology for evaluating the feasibility, regarding costs and emissions, of concepts and technologies within freight transportation chains. This has been accomplished by the development of a cost modal, Intermodal Transport Cost Model (ITCM). From the results of the case study one can conclude that a regional rail based intermodal transport system regarding costs is on the threshold of feasibility in the studied region. As for emissions, all evaluated intermodal transport chains contribute to a significant decrease in CO2 emissions compared to unimodal road haulage. The loading space utilization of the train and the transshipment cost are the most critical parameters. The latter restricting the competitiveness of intermodal services to long distances as it is not proportional to transported distance but rather to the utilization rate of resources. Hence, the concept of cost-efficient small scale (CESS) terminals is introduced in this study.

    A main prerequisite in order to make the intermodal liner train efficient is a stable and balanced flow of goods with optimized loading space utilization along the route. As the objective is to consolidate small flows, imbalances along the route will constitute an obstacle for the liner train to be competitive. Thus regarding loading space utilization it is necessary to consolidate other freight flows in the train in order to achieve high loading space utilization and a balanced flow along the route. The third parameter which is critical for the results are the fuel prices, where a sensitivity analysis of the results shows that if diesel prices would increase so would the feasibility of the intermodal option. The same is also valid for train length increase as long as the loading space utilization is maintained.

    The results of the feasibility study indicate that the evaluated transshipment technologies are closing the gap for intermodal transport to unimodal road haulage regarding transport cost over short- and medium distances and that they contribute to a substantial reduction of CO2 emissions. However, it is essential that also the transport quality is ensured, especially regarding reliability and punctuality. Thus a demonstration project is recommended as these aspects require operational testing. This is particularly crucial regarding novel transshipment technologies.

     

  • 198.
    Kornevs, Maksims
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Kringos, Niki
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Meijer, Sebastiaan
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    A Research Agenda for Green Procurement of Infrastructures2014In: 2014 International Conference on Engineering, Technology and Innovation: Engineering Responsible Innovation in Products and Services, ICE 2014, IEEE Computer Society, 2014, p. 6871604-Conference paper (Refereed)
    Abstract [en]

    Construction and maintenance of road infrastructure is a major source of emissions and energy usage. Procuring green roads, however, is neither commonplace nor trivial to implement. New ways to enhance the green procurement of roads are therefore needed, and can potentially involve life cycle assessment and green labelling methods. Considering the complexity of the pavement industry sector with its many actors and structures, implementing such innovations in the procurement process is surrounded with a series of uncertainties. The current paper formulates a research agenda for green procurement of roads by looking into potential mechanisms for future procurement. Given the objective of green procurement, the paper is focusing on the question what are the short term and long term effects of potential combinations of life cycle assessment principles and procurement process structures on infrastructure costs, risks, environmental impact and the structure of the road sector. Six different approaches are presented and reviewed for relevant earlier work in the literature. Based upon the complexities found, the authors discuss the challenges in finding a matching single research method. A solution is proposed for a holistic approach using gaming simulation, since it allows evaluating the procurement of infrastructure as a complex adaptive system.

  • 199. Kosonen, Iisakki
    et al.
    Ma, Xiaoliang
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    An Agent-base Traffic Signal Control System: Autonomous Features2013Conference paper (Refereed)
  • 200.
    Kottenhoff, Karl
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Altered states2005In: Railway Interiors International, 2005Chapter in book (Refereed)
1234567 151 - 200 of 457
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