Aptamer

In this paper we study the effects of using ruin and recreate methods in a replanning phase of a dynamic dial-a-ride problem. Several such methods are proposed, and a modeling system is used to evaluate how they improve the quality of the solutions. We show that simple changes to existing planning methods can increase the efficiency of the service. Two cases, with different forms of costs inflicted on the vehicles, are evaluated and significant improvements are found in both cases. The best results of our study are found with ruin methods based on removal of sequences of requests

Financial Inclusion and the “War for Cash”

The 4G standard Long Term Evolution (LTE) has been developed for high-bandwidth mobile access for today's data-heavy applications, consequently, a better experience for the end user. Since cellular communication is ready available, LTE communication has been designed to work at high speeds for vehicular communication. The challenge is that the protocols in LTE/LTE-Advanced should not only provide good packet delivery but also adapt to changes in the network topology due to vehicle volume and vehicular mobility. It is a critical requirement to ensure a seamless quality of experience ranging from safety to relieving congestion as deployment of LTE/LTE-Advanced become common. This requires learning how to improve the LTE/LTE-Advanced model to better appeal to a wider base and move toward additional solutions. In this paper we present a feasibility analysis for performing vehicular communication via a queueing theory approach based on a multi-server queue using real LTE traffic. A M/M/m model is employed to evaluate the probability that a vehicle finds all channels busy, as well as to derive the expected waiting times and the expected number of channel switches. Also, when a base station (eNB) becomes overloaded with a single-hop, a multi-hop rerouting optimization approach is presented

A Framework for Evaluation and Design of an Integrated Public Transport System

Operators of public transport always try to make their service as attractive as possible, to as many persons as possible and in a so cost effective way as possible. One way to make the service more attractive, especially to elderly and disabled, is to offer door-to-door transportation. The cost for the local authorities to provide this service is very high and increases every year. To better serve the needs of the population and to reduce the cost for transportation of elderly and disabled, public transportation systems are evolving towards more flexible solutions. One such flexible solution is a demand responsive service integrated with a fixed route service, together giving a form of flexible public transport system. The demand responsive service can in such a system be used to carry passengers from their origin to a transfer location to the fixed route network, and/or from the fixed route network to their destination. This thesis concerns the development of a framework for evaluation and design of such an integrated public transport service. The framework includes a geographic information system, optimization tools and simulation tools. This framework describes how these tools can be used in combination to aid the operators in the planning process of an integrated service. The thesis also presents simulations made in order to find guidelines of how an integrated service should be designed. The guidelines are intended to help operators of public transport to implement integrated services and are found by evaluating the effects on availability, travel time, cost and other service indicators for variations in the design and structure of the service. In a planning system for an integrated public transport service, individual journeys must in some way be scheduled. For this reason the thesis also presents an exact optimization model of how journeys should be scheduled in this kind of service.Report code: LiU-TEK-LIC- 2006:38</p

Modeling and Simulation of Dial-a-Ride and Integrated Public Transport Services

Traditional public transport systems are most often insufficient to provide a good transport service to everyone. Especially, it is not always possible for elderly and disabled persons to use the regular system consisting of timetabled services operating along fixed routes. Normally there is some specific service, often called paratransit, offered to these groups of customers. Such transport services provide better service to these customers, but to a higher cost. This thesis considers planning and evaluation of public transport services that are based on the concept of a dial-a-ride service. This kind of service is suitable for elderly and disabled and often operated as a door-to-door service, where customers are served on demand and rides are coordinated via a call-center. The thesis is divided into two parts. In the first part, a modeling system for simulation of dial-a-ride services is presented. It can be used as a tool to study how different ways of operating a dial-a-ride service, affect the performance and efficiency of the service. This system is used to evaluate how algorithmic changes, based on ruin-and-recreate methods, can improve the replanning of already inserted requests, and thereby improve the scheduling. The modeling system is also used to examine the effects of using zone-based distance estimates instead of true, address-based, distances when computing the schedules. The results show that only small differences are found.The second part of the thesis concerns an extension to dial-a-ride services. By combining a dial-a-ride service with a fixed route service, an integrated dial-a-ride service is created, where some part of each journey may be carried out by the fixed route service. An exact mathematical formulation of this problem is presented and it is shown that the formulation is strengthened by valid inequalities, variable substitution and subtour elimination constraints. Simulations of an integrated service are also performed to analyze and evaluate how the attractiveness and operating costs of the service depend on how the demand responsive service is operated

Analysis of the level of usage among trucks in forestry

Denna rapport behandlar framtagandet av en modell för beräkning av lastbilars nyttjandegrad. Vidare beskrivs hur denna modell har implementerats och vilka möjliga ekonomiska besparingar som finns att hämta med ett ökat nyttjande. Den kostnadskalkyl som upprättades för att kunna beräkna dessa möjliga besparingar resulterade i en kalkylerad timkostnad på 551 SEK per timme och lastbil. De resultat som beräkningarna av lastbilarnas nyttjandegrader gav, tyder på att bilarna i den södra regionen, som förväntat, hade en klart lägre nyttjandegrad än övriga. Mer oväntat var dock att detta till stor del berodde på ett lågt kapacitetsutnyttjande. Ett förslag på ny utformning av den databas vari information om utförda transporter registreras har också tagits fram. Om databasen omarbetas enligt detta förslag, eller på annat lämpligt sätt, skulle den här typen av beräkningar kunna snabbas upp betydligt. De totala ekonomiska besparingarna som skulle uppnås om samtliga bilar höll ett kapacitetsutnyttjande och ett tidsutnyttjande motsvarande medelvärdet av de bästa 25 procenten i respektive kategori, motsvarar 14,1%, alltså nästan 36 miljoner SEK per år. Stora problem ses dock med att kunna förverkliga dessa besparingar, åtminstone på någorlunda kort sikt

Utformning av underhållsområden på större driftplatser - verksamhetsstudie

Denna rapport ger en kunskapsgrund om de praktiska förutsättningarna, kravbild, och forskningsläge för utformning av underhållsområden på större driftplatser. Rapporten inleds med en bakgrund och motivering till behovet av underhållsområden, samt en beskrivning av hur studien har genomförts. En genomgång av förutsättningar och begränsningar visar bland annat att de tekniska delsystemen (spår-, signal-, och elkraftsystem) måste beaktas eftersom de har olika sektionering, gränspunkter och skyddsgivning för de arbeten som behöver utföras, samt att trafikeringsbehoven och dess variation behöver beskrivas på en generell nivå (oberoende av en specifik tidtabell), både vad gäller linjetrafik, växling och uppställning.  Det centrala kapitlet är en krav- och behovsanalys. Där dokumenteras först vilka allmänna egenskaper som fördefinierade underhållsområden behöver uppfylla, varefter tre avsnitt följer som diskuterar specifika behov som ställs av de tre verksamhetsgrenarna underhåll, planering, och trafikledning. Ett viktigt resultat är att inga stora målkonflikter har identifierats vad gäller utformningen av underhållsområden samt att en samstämmighet råder om att trafikpåverkan bör vara den huvudsakliga värderingsgrunden för områdenas utformning. Den genomförda litteraturstudien har identifierat en relativt omfattande forskning om olika partitioneringsproblem, men bara ett fåtal publikationer inom rälsbundna transporter. För hantering av kapaciteter på driftplatser finns det metoder som kan hantera en övergripande trafikbild, men ännu inget bra stöd för analys av restkapacitet vid olika typer av tidsbegränsade spårreduktioner. Någon forskning om kombinationen av partitionering, eller indelning i underområden, av en driftplats bestående av flera delsystem där målet är att kunna hantera trafikbelastningen så bra som möjligt på den resterande spårkapaciteten har vi inte kunnat finna.  Vi rekommenderar att Trafikverket vidareutvecklar sitt metodstöd för utformning av underhållsområden inom ramen för målområdet som arbetar med servicefönster. Både i detta metodstöd och för framtida forskning tror vi att den identifierade probabilistiska kapacitetsmodellen för driftplatser kan vara en lämplig grund.  Arbetet har utförts i förstudieprojektet UFO (Utformning av underhållsområden på större driftplatser), finansierat av Trafikverket (FoI-portfölj Vidmakthålla, ärende-ID 7742, diarienummer TRV2022/138570) via branschprogrammet KAJT, Kapacitet i järnvägstrafiken (www.kajt.org).FUD-ärende 7742TRV diarienummer 2022/138570LiU projektnummer 309419LiU diarienummer ITN-2022-00260Granskning:Rapporten har genomgått en remiss på Trafikverket och är oberoende forskningsgranskad av Martin Joborn, Adj. bitr. professor vid Linköpings Universitet</p

A metaheuristic for evaluation of an integrated special transport service

This work concerns evaluation of integrated demand responsive services, in which certain parts of the passengers door-to-door journeys are served by fixed route public transport. The purpose of combining a special transport service with a fixed route service is to reduce the high, publicly subsidized, operational costs of the special transport service. To be able to recommend in which situations, or areas, it is beneficial to use an integrated service we present a metaheuristic for solving the routing problem in such a service. The metaheuristic can be implemented as part of an evaluation tool for policy makers and officials, providing insights into the effects of an integrated demand responsive service compared to a non-integrated. The metaheuristic is based on the adaptive large neighbourhood search (ALNS) framework. It is applied to a data set from a real-world, rural, demand responsive special transport service and the fixed route service available in the area. The objective used in our heuristic is to minimize the distance driven by the demand responsive vehicles. The distance driven is strongly related to the operational cost of the service. Our tests show that the distance driven by the demand responsive vehicles is reduced by 16%, giving a substantial cost reduction for the special transport service in the given area. Highlights Evaluation of integrated demand responsive service Combining special transport with a fixed route service to reduce operational costs Metaheuristic, based on the adaptive large neighbourhood search (ALNS) framework Comparing integrated service to non-integratedFunding Agencies|Swedish Governmental Agency for Innovation Systems (VINNOVA)Vinnova</p

Improving paratransit scheduling using ruin and recreate methods

In this paper we study the effects of using ruin and recreate methods in a replanning phase of a dynamic dial-a-ride problem. Several such methods are proposed, and a modeling system is used to evaluate how they improve the quality of the solutions. We show that simple changes to existing planning methods can increase the efficiency of the service. Two cases, with different forms of costs inflicted on the vehicles, are evaluated and significant improvements are found in both cases. The best results of our study are found with ruin methods based on removal of sequences of requests

The integrated dial-a-ride problem with timetabled fixed route service

This paper concerns operational planning of door-to-door transportation systems for the elderly and/or disabled, who often need a more flexible transportation system than the rest of the population. Highly flexible, but very costly direct transportation is often offered as a complement to standard fixed route public transport service. In the integrated dial-a-ride problem (IDARP), these modes of transport are combined and certain legs of the passengers journeys may be performed with the fixed route public transport system. We extend the IDARP and include timetables for the fixed route services, forcing the fleet of vehicles to schedule the arrival at transfer locations with care. Two mixed integer linear programming formulations of the integrated dial-a-ride problem with timetables are presented and analyzed. The key modeling challenge is that of the transfers between the fleet of vehicles and the fixed route public transport system. The formulations differ in how the transfers are modeled and the differences are thoroughly discussed. The computational study compares the formulations in terms of network size, computational time and memory usage and conclusions about their performances are drawn

The Integrated Dial-a-Ride Problem

In this paper we present a formulation of the Integrated Dial-a-Ride (IDARP). This problem is to schedule dial-a-ride requests, where some part of each journey may be carried out by a fixed route service. The IDARP is a generalization of the Dial-a-Ride Problem. An arc-based formulation is proposed, and it is shown how the model can be made easier to solve by arc elimination, variable substitution and the introduction of subtour elimination constraints. Small instances of the IDARP can be solved using an exact solution method, and one such instance is studied. We also describe how input and output data can be created and visualized in a geographic information system