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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Automated Gravel Road Condition Assessment : A Case Study of Assessing Loose Gravel using Audio Data

Saeed, Nausheen January 2021 (has links)
Gravel roads connect sparse populations and provide highways for agriculture and the transport of forest goods. Gravel roads are an economical choice where traffic volume is low. In Sweden, 21% of all public roads are state-owned gravel roads, covering over 20,200 km. In addition, there are some 74,000 km of gravel roads and 210,000 km of forest roads that are owned by the private sector. The Swedish Transport Administration (Trafikverket) rates the condition of gravel roads according to the severity of irregularities (e.g. corrugations and potholes), dust, loose gravel, and gravel cross-sections. This assessment is carried out during the summertime when roads are free of snow. One of the essential parameters for gravel road assessment is loose gravel. Loose gravel can cause a tire to slip, leading to a loss of driver control.  Assessment of gravel roads is carried out subjectively by taking images of road sections and adding some textual notes. A cost-effective, intelligent, and objective method for road assessment is lacking. Expensive methods, such as laser profiler trucks, are available and can offer road profiling with high accuracy. These methods are not applied to gravel roads, however, because of the need to maintain cost-efficiency.  In this thesis, we explored the idea that, in addition to machine vision, we could also use machine hearing to classify the condition of gravel roads in relation to loose gravel. Several suitable classical supervised learning and convolutional neural networks (CNN) were tested. When people drive on gravel roads, they can make sense of the road condition by listening to the gravel hitting the bottom of the car. The more we hear gravel hitting the bottom of the car, the more we can sense that there is a lot of loose gravel and, therefore, the road might be in a bad condition. Based on this idea, we hypothesized that machines could also undertake such a classification when trained with labeled sound data. Machines can identify gravel and non-gravel sounds. In this thesis, we used traditional machine learning algorithms, such as support vector machines (SVM), decision trees, and ensemble classification methods. We also explored CNN for classifying spectrograms of audio sounds and images in gravel roads. Both supervised learning and CNN were used, and results were compared for this study. In classical algorithms, when compared with other classifiers, ensemble bagged tree (EBT)-based classifiers performed best for classifying gravel and non-gravel sounds. EBT performance is also useful in reducing the misclassification of non-gravel sounds. The use of CNN also showed a 97.91% accuracy rate. Using CNN makes the classification process more intuitive because the network architecture takes responsibility for selecting the relevant training features. Furthermore, the classification results can be visualized on road maps, which can help road monitoring agencies assess road conditions and schedule maintenance activities for a particular road. / <p>Due to unforeseen circumstances the seminar was postponed from May 7 to 28, as duly stated in the new posting page.</p>
52

Monitoring winter road friction using floating car data / Uppföljning av friktion på vintervägar med hjälp av fordonsdata från uppkopplade bilar

Sollén, Sofia January 2022 (has links)
More than a million people die every year due to road traffic accidents globally where one in five serious or fatal accidents occurs during severe weather conditions. Sweden is in the lead of Vision Zero, with the aim of zero casualties due to road traffic, and every year new countries and organisations accept the challenge of saving lives. Early studies have shown that one way of decreasing casualties is to implement floating car data (FCD), which is data obtained from connected road vehicles. One example of such an implementation is to gather knowledge about the current state of the road network enabling targeted winter road maintenance. By implementing FCD for winter road maintenance, besides creating safer roads, savings will be made for the environment by reducing the use of fossil fuels and salt. Since the fleet of road vehicles is going towards being fully autonomous, the volumes of FCD will increase rapidly generating new possibilities for FCD usage. Recent research regarding FCD has mainly focused on traffic flow, speed and route optimisation, together with general methods for FCD mining creating intelligent transport systems. Studies have also been made to cover the gap between road weather information systems (RWIS) monitoring the road condition and thereby improving road weather forecasts. But there is a need for research regarding the implementation of FCD at a level of action, closer to the road users improving winter road maintenance. Presented in this thesis are results gathered in the project Digital Winter, a project initiated by the Swedish Traffic Administration, where FCD regarding tire-to-road friction has been procured for all public roads in Sweden. Results show promising numbers regarding coverage and reliability for implementation of FCD for winter road maintenance follow-up, managing that assigned levels of road friction are achieved. Examples are given for different areas in Sweden where harsh weather conditions are detected and statistics show coverage of FCD both at a daily and hourly level. Multiple suppliers of FCD have been participating in Digital Winter and the measurements presented, show a correlation between suppliers of FCD and methods that today are approved for winter road maintenance follow-up in Sweden. But also that the friction measured using FCD is closer to the true road friction experienced by road users.
53

Establishing a Standardised National Data System for Evaluating Road Maintenance Emissions in Sweden

Mahmud, Z N M Zarif, Salem, Sajid January 2024 (has links)
A trustworthy and consistent data system is crucial for monitoring and reducing carbon emissions from road maintenance operations. Developing a national data reporting system requires technical support and a systemic plan involving multiple stakeholders to implement the standard. In Sweden, Trafikverket, the Swedish transport agency, recently initiated a project that proposed a solution based on the BEAst standard and outlined the current data collection methods for road maintenance. The BEAst standard is an agreed industry-driven information standard that promotes machine-readable information communication, effectively reduces costs, and increases efficiency by streamlining communication within the industry. This is to address the critical need for a trustworthy data system to monitor and reduce carbon emissions from road maintenance operations. Although the datasystem has high potential to identify the sources of carbon emissions and create mitigation measures by precisely gathering fuel use data throughout operations and maintenance activities. There are many challenges in integrating data from diverse sources into a consistent system revealed several obstacles, including differences in CO2 emissions reported by different systems, human factors affecting data quality,and limited access to cloud services. To address these challenges, this study proposes a new data reporting mechanism which requires a detailed specification of reporting parameters covering content, format, resolution, and reporting frequency using BEAst standards.
54

The non-payment for municipal services in the Vhembe District Municipality

Mavhungu, Tshamano Catherine 11 1900 (has links)
The aim of this study was to investigate reasons for non–payment by residents for services rendered by the Vhembe District Municipality. The municipalities are responsible for delivering such services as water supply, electricity, road maintenance, refuse collection and sanitation. Multistage sampling techniques were employed. The subjects in the study were grouped into clusters and a sample was taken from each cluster. In this case the municipalities that took part in the study were selected first, followed by wards, villages and households. Households in the selected villages were selected randomly to participate in the study. The results showed that although the municipalities were making an effort to raise and send bills to the residents, the residents were not forthcoming with payments. The reasons advanced for the unwillingness to pay services by residents include ignorance, poverty and simple unwillingness to pay. / Public Administration & Management / M.P.A. (Master of Public Administration and Management)
55

Geographical Information Technologies – Decision Support for Road Maintenance in Uganda

Kayondo-Ndandiko, Lydia Mazzi January 2012 (has links)
This study set out to develop a framework within which the use of Geographical Information Technologies (GITs) can be enhanced in Road Infrastructure Maintenance (RIM) in Uganda. Specifically it was guided by 3 objectives; 1. To assess the gaps in the use of GITs for RIM in Uganda and the limitations to accessing these technologies, 2. To develop a methodological framework to enhance the use of GITs in RIM and 3. To develop a Geographical Information Systems for Transportation (GIS-T) data model based on the road maintenance data requirements. A participatory approach through a series of interviews, focus group discussions, workshop &amp; conferences, document reviews, field observations &amp; measurements and GIS analysis were employed. Based on the Spatial Data Infrastructure (SDI) concept and the principle of Causality, the gaps and limitations were established to mainly be concerned with data and organisational constraints as opposed to technical issues. They were classified to include; inadequate involvement of GITs in organisational activities, inappropriate institutional arrangements, absence of data sharing frameworks, budget constraints, insufficient geospatial capacity, digital divide in the perception, adoption &amp; affordability of GITs among the stakeholders and the absence of a road maintenance Spatial Data Infrastructure (SDI). A methodological framework, comprising of 6 strategic components was developed to enhance the use of GITs in RIM. This included enactment of relevant policy components to guide GIT use, continuous capacity building, establishment of a road maintenance SDI, fostering collaboration and spatial data sharing frameworks, budgetary allocation based on defined activities inclusive of GIT initiatives, and adoption of a dynamic segmentation data model. Conceptual and logical data models were developed and proposed for the Sector. The conceptual model, presented using an entity relationship diagram, relates the road network to the point and line events occurring on it. The logical object relational model developed using the ESRI provided template represents the road and the point and line events in a total of 19 object classes. The Study concludes that in order to ground GIT benefits in the sector; technical, data and organisational concerns involved in GIT undertakings should be accorded equal emphasis. Institutionalisation and diffusion of GITs as aspects of the component strategies are regarded capacity building mechanisms earmarked to boost success in GIT initiatives. Further research on diffusion and funding models for GIT initiatives is recommended. It is suggested that aspects of the proposed model be considered when establishing GIT standards for the sector. The RIM sector is encouraged to embrace Science and Technology and to participate in Research and Development and particularly to adopt the culture of innovation considering the ready availability of off the shelf equipment, freeware and open source software that can foster informed decision making.
56

Integration av sensorteknik i underhållsprocessen för vinterväghållning / Integration of sensor technology in the winter road maintenance process

Kohberg, Fanny January 2019 (has links)
Winter road maintenance is a necessity during the winter in Sweden, since the weather reduce traffic safety and accessibility, which have great impact on people and society in general. Unlike the degradation process of paved road surface and subgrade, that develops slowly over several years, the general state of the winter road can change significantly within a couple of hours, thus demanding more of road maintenance organisations when it comes to planning and initiating maintenance actions. Today there is a wide range of available sensor technology, that can be utilized to monitor the condition of the winter road and provide decision makers with the required information to initiate maintenance activities at the right time. However, it is necessary for the user, e.g. maintenance staff and decision makers, to know how this type of technology can be applied to make the winter road maintenance more efficient. The aim of this thesis is to define the winter road maintenance process, what obstacles and problems are present and the information requirements that are associated with planning, initiating and performing the winter road maintenance activities. The thesis focuses on the maintenance process for municipalities in northern Sweden using the city of Kiruna as a case study. An interview study was performed at Tekniska Verken in Kiruna to collect empirical data, which forms the basis for the process- and flow charts that are presented in the result. Common failure modes, connected to the failures that usually leads to the initiation of a maintenance activity, are identified, based on the interviews and the quality declaration for winter road maintenance. The failure modes were connected to the workflows, to show the phases of the workflow where the information is useful. Based on this, suitable sensor technology is proposed, which partly or fully meet the identified information requirements, and monitors the interesting failure modes of each maintenance activity. The results show that the greatest need for information is found in the stage of assessment and decision-making regarding initiation of maintenance actions, especially when it comes to initiation of snow plowing and de-icing activities. Using vehicle-based sensor technology, the condition of the road can be continuously monitored, and the initiation of maintenance activities can be triggered when reaching a threshold. Having road weather information stations, e.g. monitoring air and road temperature, wind speed, precipitation and road condition, is also an important source of information for municipal winter road maintenance. The use of sensor technology results in maintenance processes with fewer activities and decision steps, and it generates more reliable data that simplifies the decision-making. / Vinterväghållning är en nödvändighet under vinterhalvåret i Sverige, då väderlek har en stor påverkan på trafiksäkerhet och framkomlighet för trafikanter. Till skillnad från nedbrytningen av belagd väg under barmarkssäsongen, som sker stegvis under flera år, kan vintervägens tillstånd försämras avsevärt inom bara ett par timmar. Detta ställer högre krav på vägunderhållsorganisationer vad gäller planering och initiering av underhållsåtgärder. Idag finns ett brett utbud av sensorteknik som kan användas för att övervaka vintervägens tillstånd, och förse beslutsfattare med nödvändig information för att kunna initiera underhållsaktiviteter vid rätt tidpunkt. Det är dock nödvändigt att användaren, dvs. underhållspersonal och beslutsfattare, har kunskap om hur denna teknik kan användas för att effektivisera vinterväghållningen. Syftet med arbetet är att ta reda på hur underhållsprocessen för kommunal vinterväghållning är utformad, vilka hinder och problem som förekommer samt vilket informationsbehov som finns i samband med planering, initiering och utförande av vinterväghållningsaktiviteter. Arbetet är avgränsat till att analysera vinterväghållningen i Kiruna kommun. En intervjustudie utfördes vid Tekniska Verken i Kiruna för insamling av empiriskt material, vilket utgjorde underlaget för de process- och flödeskartor som presenteras i resultatet. Med utgångspunkt ur intervjumaterialet och kommunens kvalitetsdeklaration för vinterväghållning, identifierades vanliga felmoder kopplade till de funktionsfel som leder till initiering av underhållsaktivitet. Felmoderna kopplades sedan till arbetsflödena, genom att visa i vilket skede i arbetet som information om dessa är användbar. Utifrån detta gavs förslag på lämplig sensorteknik som helt eller delvis kan tillgodose informationsbehovet som identifierats, samt övervaka de felmoder som är intressanta för respektive underhållsaktivitet. Resultatet av undersökningen visar att det är vid bedömning och beslut om initiering av underhållsåtgärd som informationsbehovet är störst, framför allt när det handlar om initiering av snöröjning och halkbekämpning. Genom att använda sensorteknik för kontinuerlig övervakning av vägens tillstånd, kan underhållsaktiviteter initieras vid definierade gränsvärden. Egna vägväderstationer som övervakar och mäter exempelvis luft- och vägtemperatur, vindstyrka, nederbördsmängd och typ samt väglag, kan vara till nytta för den kommunala vinterväghållningen oavsett vilken underhållsaktivitet det handlar om. Användningen av denna typ av teknik leder till effektiviserade underhållsprocesser med färre aktiviteter och beslutssteg, samt förenklad beslutsfattning baserat på mer tillförlitliga mätdata.
57

Road Design for Future Maintenance : Life-cycle Cost Analyses for Road Barriers

Karim, Hawzheen January 2011 (has links)
The cost of a road construction over its service life is a function of design, quality of construction as well as maintenance strategies and operations. An optimal life-cycle cost for a road requires evaluations of the above mentioned components. Unfortunately, road designers often neglect a very important aspect, namely, the possibility to perform future maintenance activities. Focus is mainly directed towards other aspects such as investment costs, traffic safety, aesthetic appearance, regional development and environmental effects. This doctoral thesis presents the results of a research project aimed to increase consideration of road maintenance aspects in the planning and design process. The following subgoals were established: Identify the obstacles that prevent adequate consideration of future maintenance during the road planning and design process; and Examine optimisation of life-cycle costs as an approach towards increased efficiency during the road planning and design process. The research project started with a literature review aimed at evaluating the extent to which maintenance aspects are considered during road planning and design as an improvement potential for maintenance efficiency. Efforts made by road authorities to increase efficiency, especially maintenance efficiency, were evaluated. The results indicated that all the evaluated efforts had one thing in common, namely ignorance of the interrelationship between geometrical road design and maintenance as an effective tool to increase maintenance efficiency. Focus has mainly been on improving operating practises and maintenance procedures. This fact might also explain why some efforts to increase maintenance efficiency have been less successful. An investigation was conducted to identify the problems and difficulties, which obstruct due consideration of maintainability during the road planning and design process. A method called “Change Analysis” was used to analyse data collected during interviews with experts in road design and maintenance. The study indicated a complex combination of problems which result in inadequate consideration of maintenance aspects when planning and designing roads. The identified problems were classified into six categories: insufficient consulting, insufficient knowledge, regulations and specifications without consideration of maintenance aspects, insufficient planning and design activities, inadequate organisation and demands from other authorities. Several urgent needs for changes to eliminate these problems were identified. One of the problems identified in the above mentioned study as an obstacle for due consideration of maintenance aspects during road design was the absence of a model for calculating life-cycle costs for roads. Because of this lack of knowledge, the research project focused on implementing a new approach for calculating and analysing life-cycle costs for roads with emphasis on the relationship between road design and road maintainability. Road barriers were chosen as an example. The ambition is to develop this approach to cover other road components at a later stage. A study was conducted to quantify repair rates for barriers and associated repair costs as one of the major maintenance costs for road barriers. A method called “Case Study Research Method” was used to analyse the effect of several factors on barrier repairs costs, such as barrier type, road type, posted speed and seasonal effect. The analyses were based on documented data associated with 1625 repairs conducted in four different geographical regions in Sweden during 2006. A model for calculation of average repair costs per vehicle kilometres was created. Significant differences in the barrier repair costs were found between the studied barrier types. In another study, the injuries associated with road barrier collisions and the corresponding influencing factors were analysed. The analyses in this study were based on documented data from actual barrier collisions between 2005 and 2008 in Sweden. The result was used to calculate the cost for injuries associated with barrier collisions as a part of the socio-economic cost for road barriers. The results showed significant differences in the number of injuries associated with collisions with different barrier types. To calculate and analyse life-cycle costs for road barriers a new approach was developed based on a method called “Activity-based Life-cycle Costing”. By modelling uncertainties, the presented approach gives a possibility to identify and analyse factors crucial for optimising life-cycle costs. The study showed a great potential to increase road maintenance efficiency through road design. It also showed that road components with low investment costs might not be the best choice when including maintenance and socio-economic aspects. The difficulties and problems faced during the collection of data for calculating life-cycle costs for road barriers indicated a great need for improving current data collecting and archiving procedures. The research focused on Swedish road planning and design. However, the conclusions can be applied to other Nordic countries, where weather conditions and road design practices are similar. The general methodological approaches used in this research project may be applied also to other studies. / <p>QC 20110407</p>
58

Efficient Winter Road Maintenance : A Study of Technical and Contractual Issues

Abdi, Adel January 2014 (has links)
Since ancient times, roads have tied people and cultures together. Roads have been createdwith the aim of facilitating trade and cultural exchange among different regions in the world. After the technologic development in vehicle industry and dramatically increase of motoring in the world during the past century road communication has gained a great importance for transporting people and goods. Thus, good safety and accessibility on roads all year round is now a vital necessity for a healthy economy in all modern societies. In order to keep roads safe, available for use with high transport quality they need to be maintained in real time. One of the most difficult tasks in this context is to keep the roads in good condition and accessible even during winter. The main objective of this doctoral thesis is to attempt to specify the most efficient ways of executing winter road maintenance.  The preliminary issue in this context is whether it is the use of current assistive tools, that is, technical aspects that should be optimized and developed or whether it is the way in which winter maintenance services are procured and outsourced, that is, contractual aspects that should be improved which could give the optimal impact for both clients and contractors and make winter road maintenance more effective, or both issues. In order to define the outline of the research project a comprehensive state of the art survey was initiated with the intention of collecting and gaining insights into the earlier studies in the research area. Three basic areas associated with the performance of winter road maintenance were considered to be most relevant for review due to the anchorage between the areas. The selected areas were climatological, technical and contractual aspects. The literature review was followed by an electronic questionnaire survey. The results of the study in this stage showed that current technical methods almost functioned in a reasonable manner but there was an imprecise dissatisfaction with the current maintenance contract. The second stage of the research consisted of a number of additional empirical investigations in order to identify contractual problematic issues behind the current winter road maintenance in Sweden. Generally, those factors that are rarely considered as potential underlying causes to costly performance of winter road maintenance in Sweden were studied in this research project for example improper use of related technical assistive tools, procurement of improper bundled winter services and inappropriate contract structure. This thesis consists of six papers, five of which are related to each other, and the first one is completely independent but within research area. Findings in the thesis contributes to extend understanding about; how designing appropriate contracts can improve winter road maintenance, how proper use of assistive tools can reduce unnecessary winter road maintenance costs and minimize road traffic disruptions and delays, how a partnering structure in contracts can create confidence and trust between clients and contractors that in turn leads to minimizing or eliminating conflicts and disputes between parties involved, how choice of appropriate procurement methods through proper bundling of winter road services can contribute to shorten the procurement process and create incentives for contractors, and how selection of proper payment mechanisms can contribute to higher service quality of performed winter road measures. Additionally, an adequate knowledge and understanding of climate, proper knowledge of road weather and its impact on winter road traffic is essential for contribution of better planning of how to maintain the road network during winter. Since understanding about winter issues and its effect on winter road traffic is far from complete and winter road maintenance in the cold regions is a similar challenge, broad and complex, the results of this research may even contribute to improving winter maintenance problems in the countries with severe winters like Sweden. / <p>QC 20140227</p>
59

The non-payment for municipal services in the Vhembe District Municipality

Mavhungu, Tshamano Catherine 11 1900 (has links)
The aim of this study was to investigate reasons for non–payment by residents for services rendered by the Vhembe District Municipality. The municipalities are responsible for delivering such services as water supply, electricity, road maintenance, refuse collection and sanitation. Multistage sampling techniques were employed. The subjects in the study were grouped into clusters and a sample was taken from each cluster. In this case the municipalities that took part in the study were selected first, followed by wards, villages and households. Households in the selected villages were selected randomly to participate in the study. The results showed that although the municipalities were making an effort to raise and send bills to the residents, the residents were not forthcoming with payments. The reasons advanced for the unwillingness to pay services by residents include ignorance, poverty and simple unwillingness to pay. / Public Administration and Management / M.P.A. (Master of Public Administration and Management)
60

Hydronic Pavement Systems for Sustainable Winter Road Maintenance in Sweden : A Study of Hamnbacken in Visby / Uppvärmda vägar för hållbar halkbekämpning i Sverige

Barikan, Chirin January 2019 (has links)
In countries with harsh winter climates extensive winter road maintenance is necessary to achieve traffic accessibility and road safety. These measures have high economic and environmental costs as snow free roads and winter road maintenance in Sweden today is achieved by a combination of mechanical snow clearance and the spreading of salt to prevent ice formation. The salt ends up in the roadside environment and has negative effects on groundwater and vegetation. An alternative to traditional winter road maintenance to obtain non-skid winter roads is the use of hydronic pavement(HP) systems. Existing HP systems in Sweden are powered by district heating which limits the application to urban locations. The goal is to utilize renewable energy sources such as geoenergy which can be used in both rural and urban locations. This thesis suggests Hamnbacken in Visby as a pilot project for a full-scale application of the proposed HP system using surface water source heat.The weather related road surface conditions on Hamnbacken, and the potential of a renewable energysource have been examined in this study and the proposed location has been found favourable for a HP system. / Länder med övervägande kallt vinterklimat är halkbekämpning en nödvändighet för trafikens framkomlighet och säkerhet. Åtgärderna som vidtas för att få snö- och isfria vägar är kostsamma samt har en hög miljöpåverkan, ett vedertagligt exempel är plogning och saltning. Saltet hamnar i slutändan inom vägens omgivande områden och har en negativ påverkan på grundvatten och vegetation. En alternativ lösning till traditionell halkbekämpning är uppvärmda vägar för att uppnå ett halkfritt vinterväglag. Befintliga väguppvärmningssystem i Sverige försörjs av fjärrvärme vilket är en begräsning då tillgången till fjärrvärme finns i anslutning till tätorter. Målet är att utnyttja förnybara energikällor såsom geoenergi som är tillgänglig både i tätorter och på landsbygden. Det här examensarbetet undersöker Hamnbacken i Visby som ett pilotprojekt för en fullskalig implementering av väguppvärmningssystem där sjövärme används som energikälla. Denna studie har undersökt väderrelaterade vägförhållanden på Hamnbacken samt potentialen för användning av sjövärme. Den föreslagna platsens förutsättningar har visat sig vara gynnsamma i detta avseende.

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