| 1. |
- Kristanl, Matej, et al.
(författare)
-
The Seventh Visual Object Tracking VOT2019 Challenge Results
- 2019
-
Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
-
Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
|
|
| 2. |
- Almlöf, Erik, 1985-, et al.
(författare)
-
Frameworks for assessing societal impacts of automated driving technology
- 2022
-
Ingår i: Transportation planning and technology (Print). - : Taylor & Francis. - 0308-1060 .- 1029-0354. ; 45:7, s. 545-572
-
Tidskriftsartikel (refereegranskat)abstract
- Numerous studies have studied the impacts of automated driving (AD) technology on e.g. accident rates or CO2 emissions using various frameworks. In this paper we present an overview of previous frameworks used for societal impacts and review their advantages and limitations. Additionally, we introduce the Total Impact Assessment (TIA) framework developed by the Swedish Transport Administration and use this framework to evaluate three scenarios for AD bus services in Stockholm. We conclude that the reviewed frameworks cover different aspects of AD technology, and that e.g. cybersecurity and biodiversity are areas largely neglected. Furthermore, most frameworks assume effects to be homogenous, when there may be large variation in e.g. perceived security. The TIA framework does not manage to include all societal aspects of AD technology, but has great benefits and manages to provide important insights of the societal impacts of AD technology, especially how effects may wary for different actors.
|
|
| 3. |
- Almlöf, Erik, 1985-, et al.
(författare)
-
Frameworks for assessing societal impacts of self-driving technology
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Numerous studies have studied the impacts of self-driving technology on e.g. accident rates or CO2 emissions using various frameworks. In this paper we present an overview of previous frameworks used for societal impacts, and review their advantages and limitations. Additionally, we introduce the Total Impact Assessment (TIA) framework developed by the Swedish Transport Administration and use this framework to evaluate three scenarios for self-driving bus services in Stockholm. We conclude that the reviewed frameworks cover different aspects of self-driving technology, and that e.g. cybersecurity and biodiversity are areas neglected by most frameworks. Furthermore, most frameworks assume effects to be homogenous, when there may be large variation in e.g. perceived security. The TIA framework does not manage to include all societal aspects of self-driving technology, but has great benefits and manages to provide important insights of the societal impacts of self-driving technology, especially how effects may wary for different actors.
|
|
| 4. |
- Almlöf, Erik, 1985-
(författare)
-
Slutrapport - Självkörande fullängdsbuss på Tvärförbindelse Södertörn
- 2021
-
Rapport (populärvet., debatt m.m.)abstract
- Föreliggande slutrapport är finansierad av Trafikverkets FoI portfölj, strategiska initiativ,för projekt Självkörande eldriven stombuss på Tvärförbindelse Södertörn – En skalbarfallstudie (TRV 2019/118695). Partners i projektet är Trafikverket, Scania, Volvo, Keolis,KTH samt Sweco där även Trafikförvaltningen Region Stockholm, Nobina och projektTvärförbindelse Södertörn har bidragit till arbetet som pågått från maj 2020 till mars 2021.Ansvarig för projektet inom Trafikverket har varit Stora projekt.För att skapa en förståelse för konsekvenser av tekniska utveckling i relation tillnödvändiga fysiska och digitala åtgärder har tre scenarier tagits fram: Bus Driver Plus,Automation with Adaption och Automation Utopia. Dessa scenarier beskriver olika nivåerav automation och behov av kringliggande stödsystem. I det första scenario finns enförare ombord på bussen som tar över körningen vid farliga situationer. Det andrascenariot avser en självkörande buss utan förare där den fysiska infrastrukturen haranpassats genom ett införande av ett eget busskörfält. Det sista scenariot beskriver enframtid där bussen helt förlitar sig på digital teknik och en operatör kontrollerar körningenav flera fordon från ett avsides kontrolltorn.De tre scenarierna utvärderades genom en samlad effektbedömning, Trafikverkets metodför att utvärdera åtgärder. Resultaten visar att den största vinsten av automatisering kanhandla om resenärernas bekvämlighet och inte nödvändigtvis om att minimera kostnaderför förare. Antaganden om att resenärerna kan uppleva resan bekvämare är troligtvisöverskattade, men resultaten visar att även små förbättringar i bekvämlighet kan ge storasamhälleliga vinster.Scenariot där bussen har ett eget körfält innebär mycket stora kostnader och är troligtvisinte ekonomiskt försvarbart. Dessutom kommer enbart en busslinje att trafikeramotorleden som dessutom består av 3 tunnlar. Vidare är det inte säkert att den aktör somgör nödvändiga investeringar är den aktör som får ta del av de samhälleliga vinsterna. Iscenariot skulle Trafikverket stå för stora delar av investeringskostnaden, medan vinsten för personalbesparingar uppstår för Region Stockholm och kollektivtrafikresenärerna somåker längs sträckan.Projektet har även undersökt hur multimodala hubbar (nod som möjliggör smidigt bytemellan olika transportmedel) längs med förbindelsen kan stödja eldrivna och självkörandebussar. Det är viktigt att ny väginfrastruktur bidrar till en attraktiv kollektivtrafik därresenärer i första hand väljer buss istället för bil. För att eldrivna och självkörande bussarska införas behöver Region Stockholm ställa nya krav i upphandlingar för attåstadkomma en förändring i transportsystemet. Nya krav som skapar ekonomiskaincitament för operatörer som utför den operativa verksamheten över lång tid. Det är dockproblematiskt att ställa krav på eldrift eftersom det saknas tillgänglig infrastruktur iStockholm.Avseende självkörande fullängdsbussar är tekniken helt enkelt inte tillräckligt mogen idag.Dock tror många experter att självkörande bussar kommer att införas, både i stadsmiljöoch glesbygd, när tekniken och samhället är redo för det, gissningsvis kring år 2030.
|
|
| 5. |
- Eriksson, Per Erik, et al.
(författare)
-
How gaze time on screen impacts the efficacy of visual instructions
- 2018
-
Ingår i: Heliyon. - : Elsevier BV. - 2405-8440. ; 4:6
-
Tidskriftsartikel (refereegranskat)abstract
- This article explores whether GTS (gaze time on screen) can be useful as an engagement measure in the screen mediated learning context. Research that exemplifies ways of measuring engagement in the on-line education context usually does not address engagement metrics and engagement evaluation methods that are unique to the diverse contemporary instructional media landscape. Nevertheless, unambiguous construct definitions of engagement and standardized engagement evaluation methods are needed to leverage instructional media's efficacy. By analyzing the results from a mixed methods eye-tracking study of fifty-seven participants evaluating their visual and assembly performance levels in relation to three visual, procedural instructions that are versions of the same procedural instruction, we found that the mean GTS-values in each group were rather similar. However, the original GTS-values outputted from the ET-computer were not entirely correct and needed to be manually checked and cross validated. Thus, GTS appears not to be a reliable, universally applicable automatic engagement measure in screen-based instructional efforts. Still, we could establish that the overall performance of learners was somewhat negatively impacted by lower than mean GTS-scores, when checking the performance levels of the entire group (N = 57). When checking the stimuli groups individually (N = 17, 20, 20), the structural diagram group's assembly time durations were positively influenced by higher than mean GTS-scores.
|
|
| 6. |
- Ji, Huazhen, et al.
(författare)
-
Relationship between leadership-member exchange (LMX) and flow at work among medical workers during the COVID-19 : the mediating role of job crafting
- 2023
-
Ingår i: BMC Psychology. - : BioMed Central (BMC). - 2050-7283. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- Based on relational leadership theory and self-determination theory, this study aims to investigate the relationship between leader-member exchange (LMX), job crafting, and flow at work among medical workers in the context of the COVID-19 pandemic. Participants in the study consisted of 424 hospital employees. The results showed that: (1) the LMX positively predicted flow at work; (2) two types of job crafting (increasing structural job resources and challenging job demands) played a mediating role between the LMX and flow at work; and (3) gender did not moderate these mediating effects as suggested by previous studies. These results indicate that the LMX can not only directly predict flow at work, but also indirectly predict work-related flow through job crafting by increasing structural job resources and challenging job demands, thus providing new insights for enhancing flow experiences of medical workers.
|
|
| 7. |
- Johari, Fatemeh, et al.
(författare)
-
Urban Building Energy Modeling : State of the Art and Future Prospects
- 2020
-
Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 128
-
Forskningsöversikt (refereegranskat)abstract
- During recent years, urban building energy modeling has become known as a novel approach for identification, support and improvement of sustainable urban development initiatives and energy efficiency measures in cities. Urban building energy models draw the required information from the energy analysis of buildings in the urban context and suggest options for effective implementation of interventions. The growing interest in urban building energy models among researchers, urban designers and authorities has led to the development of a diversity of models and tools, evolving from physical to more advanced hybrid models. By critically analyzing the published research, this paper incorporates an updated overview of the field of urban building energy modeling and investigates possibilities, challenges and shortcomings, as well as an outlook for future improvements. The survey of previous studies identifies technical bottlenecks and legal barriers in access to data, systematic and inherent uncertainties as well as insufficient resources as the main obstacles. Furthermore, this study suggests that the main route to further improvements in urban building energy modeling is its integration with other urban models, such as climate and outdoor comfort models, energy system models and, in particular, mobility models.
|
|
| 8. |
- Karlsson, Marianne, 1956, et al.
(författare)
-
A National Approach to Assessing the Impacts of Mobility-as-a-Service (MaaS)
- 2019
-
Ingår i: Proceedings ICOMAAS. 2nd International Conference on Mobility as a Service. ; , s. 357-365
-
Konferensbidrag (refereegranskat)abstract
- To systematically assess the environmental, economic and social impacts of different types of MaaS, a common evaluation framework is essential. Within the KOMPIS project, a framework is developed with a basis in former projects (e.g. MaaSiFiE and IRIMS), complementary literature studies, and workshops involving different stakeholders. The framework consists of three interrelated levels; a traveller level, an organizational business level, and a societal level. For each level, performance indicators (KPIs) of ecologic, economic, and social impacts have been formulated as well as a specification of the data that must be collected. In addition, for each level a model describes the interdependency between factors termed ‘preconditions’, ‘evaluation/decision’ and ‘action’. These factors explain and describe background information that is to be collected in order to explain the outcome of impact assessments. The framework and associated data collection tools are available on the KOMPIS project website. In a next phase, feedback is to be provided by MaaS pilots to further develop the framework and related tools.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Kristan, Matej, et al.
(författare)
-
The Ninth Visual Object Tracking VOT2021 Challenge Results
- 2021
-
Ingår i: 2021 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2021). - : IEEE COMPUTER SOC. - 9781665401913 ; , s. 2711-2738
-
Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2021 is the ninth annual tracker benchmarking activity organized by the VOT initiative. Results of 71 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in recent years. The VOT2021 challenge was composed of four sub-challenges focusing on different tracking domains: (i) VOT-ST2021 challenge focused on short-term tracking in RGB, (ii) VOT-RT2021 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2021 focused on long-term tracking, namely coping with target disappearance and reappearance and (iv) VOT-RGBD2021 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2021 dataset was refreshed, while VOT-RGBD2021 introduces a training dataset and sequestered dataset for winner identification. The source code for most of the trackers, the datasets, the evaluation kit and the results along with the source code for most trackers are publicly available at the challenge website(1).
|
|
| 13. |
- Lin, Zeyu, et al.
(författare)
-
Evaluating the electron beam spot size in electron beam melting machines
- 2021
-
Konferensbidrag (refereegranskat)abstract
- Since electron beam (EB) is the main additive manufacturing (AM) tool in electron beam melting (EBM), EB spot size plays a significant role in the parts quality, surface roughness as well as the microstructure and corresponding properties. So far, the research on the relationship between the machine parameters and the EB spot size has been mainly based on the single track and powderless single track printing on a metal plate such as stainless steel. However, this method, due to material thermal properties as well as the melting phenomena, cannot reveal the actual value for the EB spot size. This research is carried out to establish a simple methodology on measuring the EB spot size in a more accurate way with a low cost. To do so, a ceramic surface coating was applied to the surface of a metal copper starting plate and stainless steel plate. Afterwards, the EB applied the tracks onto the coatings and regular metal plate. The analysis showed that the EB tracks on ceramic coated stainless steel plates could be the best replica for the electron beam among those materials tested in this work.
|
|
| 14. |
- Nordström, Carin, 1971-, et al.
(författare)
-
Working with Swedes
- 2018
-
Bok (övrigt vetenskapligt/konstnärligt)
|
|
| 15. |
- Richards, Stephen, et al.
(författare)
-
The genome of the model beetle and pest Tribolium castaneum.
- 2008
-
Ingår i: Nature. - 1476-4687. ; 452:7190, s. 949-55
-
Tidskriftsartikel (refereegranskat)abstract
- Tribolium castaneum is a representative of earth’s most numerous eukaryotic order, a powerful model organism for the study of generalized insect development, and also an important pest of stored agricultural products. We describe its genome sequence here. This omnivorous beetle has evolved an ability to interact with a diverse chemical environment as evidenced by large expansions in odorant and gustatory receptors, as well as p450 and other detoxification enzymes. Developmental patterns in Tribolium are more representative of other arthropods than those found in Drosophila, a fact represented in gene content and function. For one, Tribolium has retained more ancestral genes involved in cell-cell communication than Drosophila, and some are expressed in the growth zone crucial for axial elongation in short germ development. Systemic RNAi in T. castaneum appears to use mechanisms distinct from those found in C. elegans, but nevertheless offers similar power for the elucidation of gene function and identification of targets for selective insect control.
|
|
| 16. |
- Sadeghian, Paria, et al.
(författare)
-
A deep semi-supervised machine learning algorithm for detecting transportation modes based on GPS tracking data
- 2024
-
Ingår i: Transportation. - : Springer. - 0049-4488 .- 1572-9435.
-
Tidskriftsartikel (refereegranskat)abstract
- Transportation research has benefited from GPS tracking devices since a higher volume of data can be acquired. Trip information such as travel speed, time, and most visited locations can be easily extracted from raw GPS tracking data. However, transportation modes cannot be extracted directly and require more complex analytical processes. Common approaches for detecting travel modes heavily depend on manual labelling of trajectories with accurate trip information, which is inefficient in many aspects. This paper proposes a method of semi-supervised machine learning by using minimal labelled data. The method can accept GPS trajectory with adjustable length and extract latent information with long short-term memory (LSTM) Autoencoder. The method adopts a deep neural network architecture with three hidden layers to map the latent information to detect transportation mode. The proposed method is assessed by applying it to the case study where an accuracy of 93.94% can be achieved, which significantly outperforms similar studies.
|
|
| 17. |
- Sadeghian, Paria
(författare)
-
A Multi-Dimensional Approach to Human Mobility and Transportation Mode Detection Using GPS Data
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- GPS tracking data is an essential resource for analyzing human travel patterns and evaluating the effects on transportation systems. The primary challenge, however, is to accurately identify the modes of transportation within unlabeled GPS data. These approaches range from simple rule-based systems to advanced machine-learning techniques. This dissertation aims to bridge this gap by examining the critical features and techniques of these methods and proposing a novel approach for detecting transportation modes in GPS tracking data. To achieve this goal, a comprehensive understanding of individual journeys is crucial. Thus, this research adopts a microdata analytic approach, encompassing data collection, processing, analysis, and decision-making stages. Doing so contributes to advancing human mobility research and transportation mode detection. Paper I undertook a systematic review of transport mode detection methodologies to fill the research gap, emphasizing the predominance of supervised learning algorithms and highlighting the need for further research to address the limitations of small datasets. Paper II introduced a stepwise methodology, integrating unsupervised learning, GIS, and supervised algorithms to detect transport modes while minimizing reliance on labelled data. The Random Forest algorithm emerged as a precise but time-intensive solution. Paper III showcased a novel approach to transport mode detection using deep learning models, outperforming traditional machine learning methods. This paper signals the potential of deep learning in the field and demonstrates the importance of raw GPS data in enhancing accuracy. Paper V addressed the challenge of predicting human mobility patterns under the Hidden Markov Model (HMM) framework, highlighting the applicability of HMMs to understanding and predicting complex mobility behaviour. This paper emphasized the need for GPS tracking data in developing advanced mobility models. Paper IV ventured into hybrid methodology by combining K-means clustering with the ANP-PSO algorithm to enhance transportation mode classification. This pioneering approach improved classification accuracy while reducing dependence on labelled datasets. Collectively, these papers underscore the opportunities and limitations in human mobility research, offering insights into future directions for mitigating data quality issues and improving the accuracy of transportation mode detection. These innovative methodologies have practical implications for transportation planning, resource allocation, and intelligent transportation system development, ultimately shaping the future of transportation research and decision-making. Standardized data collection, processing, and labelling methods are crucial and need attention in future research. Future research can focus on developing such benchmarks and validation protocols to enhance the reliability and comparability of results.
|
|
| 18. |
- Sadeghian, Paria, et al.
(författare)
-
A stepwise methodology for transport mode detection in GPS tracking data
- 2022
-
Ingår i: Travel Behaviour & Society. - : Elsevier BV. - 2214-367X .- 2214-3688. ; 26, s. 159-167
-
Tidskriftsartikel (refereegranskat)abstract
- Global positioning systems (GPS) tracking data have been widely used to collect mobility data to investigate travel behaviors and identify travel patterns. Some critical travel information, such as frequently visited locations, speeds, temporal changes, can be easily extracted from the raw GPS data. However, travel information like transport modes that have been used are difficult to acquire, and more complex analytical processes are required. Previous studies have mostly adopted context-specific methods or stand-alone methods in detecting transport modes from GPS data. Most of these context-specific methods are based on a limited number of datasets since the required data labeling process is time-consuming. This paper proposes a generic stepwise methodology by integrating unsupervised learning algorithms, GIS multi-criteria process, and supervised learning algorithms for data labeling and transport mode detection. The performances of five commonly used supervised algorithms are evaluated by applying them to a large-scale GPS tracking dataset. The results indicate that the proposed stepwise methodology can reduce data labeling time while providing high precision in detecting transport modes. The evaluation shows that the Random Forest algorithm is the most preferable, with only 10% labeled data needed and it can achieve a precision of 99%.
|
|
| 19. |
- Sadeghian, Paria
(författare)
-
Human mobility behavior : Transport mode detection by GPS data
- 2021
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- GPS tracking data are widely used to understand human travel behavior and to evaluate the impact of travel. A major advantage with the usage of GPS tracking devices for collecting data is that it enables the researcher to collect large amounts of highly accurate and detailed human mobility data. However, unlabeled GPS tracking data does not easily lend itself to detecting transportation mode and this has given rise to a range of methods and algorithms for this purpose. The algorithms used vary in design and functionality, from defining specific rules to advanced machine learning algorithms. There is however no previous comprehensive review of these algorithms and this thesis aims to identify their essential features and methods and to develop and demonstrate a method for the detection of transport mode in GPS tracking data. To do this, it is necessary to have a detailed description of the particular journey undertaken by an individual. Therefore, as part of the investigation, a microdata analytic approach is applied to the problem areas, including the stages of data collection, data processing, analyzing the data, and decision making.In order to fill the research gap, Paper I consists of a systematic literature review of the methods and essential features used for detecting the transport mode in unlabeled GPS tracking data. Selected empirical studies were categorized into rule-based methods, statistical methods, and machine learning methods. The evaluation shows that machine learning algorithms are the most common. In the evaluation, I compared the methods previously used, extracted features, types of dataset, and model accuracy of transport mode detection. The results show that there is no standard method used in transport mode detection. In the light of these results, I propose in Paper II a stepwise methodology to detect five transport modes taking advantage of the unlabeled GPS data by first using an unsupervised algorithm to detect the five transport modes. A GIS multi-criteria process was applied to label part of the dataset. The performance of the five supervised algorithms was evaluated by applying them to different portions of the labeled dataset. The results show that stepwise methodology can achieve high accuracy in detecting the transport mode by labeling only 10% of the data from the entire dataset. For the future, one interesting area to explore would be the application of the stepwise methodology to a balanced and larger dataset. A semi-supervised deep-learning approach is suggested for development in transport mode detection, since this method can detect transport modes with only small amounts of labeled data. Thus, the stepwise methodology can be improved upon for further studies.
|
|
| 20. |
- Sadeghian, Paria, et al.
(författare)
-
Review and evaluation of methods in transport mode detection based on GPS tracking data
- 2021
-
Ingår i: Journal of Traffic and Transportation Engineering (English Edition). - : KEAI PUBLISHING LTD. - 2095-7564. ; 8:4, s. 467-482
-
Forskningsöversikt (refereegranskat)abstract
- Mobility data, based on global positioning system (GPS) tracking, have been widely used in many areas, such as analyzing travel patterns, investigating transport safety and efficiency, and evaluating travel impacts. Transport modes are essential factors in understanding mobility within the transport system. Therefore, in this study, a significant number of algorithms were tested for transport mode detection. However, no conclusive recommendations can be drawn regarding which method should be used. The evaluation of the performance of the algorithms was not discussed systematically either in current literature. This paper aims to provide an in-depth review of the methods applied in transport mode detection based on GPS tracking data. The performances of the reviewed methods are then compared and evaluated to provide guidance in choosing algorithms for transport mode detection based on GPS tracking data. The results indicate that the majority of current studies are based on a supervised learning method for transport mode detection. Many of the reviewed methods first require manual dataset labeling, which can produce major drawbacks, such as inefficiency and human errors. It was also found that deep learning approaches have the potential to deal with large amounts of unlabeled raw GPS datasets and increase the accuracy and efficiency of transport mode detection.
|
|
| 21. |
|
|
| 22. |
- Sadeghian, Paria, et al.
(författare)
-
Testing feasibility of using a hidden Markov model on predicting human mobility based on GPS tracking data
- 2024
-
Ingår i: Transportmetrica B. - : Taylor & Francis. - 2168-0566. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Human mobility behaviour is far from random and can be predictable. Predicting human mobility behaviour has the potential to improve location selection for facilities, transportation services, urban planning, and can be beneficial in providing more efficient sustainable urban development strategies. However, it is difficult to model urban mobility patterns since incentives for mobility is complex, and influenced by several factors, such as dynamic population, weather conditions. Thus, this paper proposes a prediction-oriented algorithm under the framework of a Hidden Markov Model to predict next-location and time-of-arrival of human mobility. A comprehensive evaluation of these two schemes for the representation of latent and observable variables is discussed. In conclusion, the paper provides a valuable contribution to the field of mobility behaviour prediction by proposing a novel algorithm. The evaluation shows that the proposed algorithm is stable and consistent in predicting the next location of users based on their past trajectories. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
|
|
| 23. |
- Vaddadi, Bhavana, Ph.D. Student, et al.
(författare)
-
Measuring System-Level Impacts of Corporate Mobility as a Service (CMaaS) Based on Empirical Evidence
- 2020
-
Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 12:17, s. 7051-
-
Tidskriftsartikel (refereegranskat)abstract
- Corporate Mobility as a Service (CMaaS) is a type of MaaS that enables mobility within as well as to and from a worksite for employees. The expected benefits of CMaaS are to support a shift towards more sustainable and more effective work-related transport activities. There is a lack of knowledge regarding the impacts of CMaaS and how its performance should be measured. This paper proposes an evaluation framework to measure CMaaS impacts at a system level. The proposed evaluation framework is then applied to evaluate a real CMaaS deployment in Sweden. This paper contributes to knowledge building and guidance to support policy and decision making for CMaaS development and implementation in the future.
|
|
| 24. |
- Vaddadi, Bhavana, 1993-
(författare)
-
Understanding the system-level for Mobility as a Service : A framework to evaluate full-scale impacts of MaaS
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mobility as a Service (MaaS), as a concept, has been widely popularised and considered to hold promising potential in reducing travel-related environmental impacts and transforming our current transport system. MaaS enables intermodal travel by providing enhanced features for users to access multiple mobility services. The combination of mobility services in MaaS solutions promotes the use of public transport, active modes and shared mobility to reduce the dependency on private vehicles and provide optimal work and travel arrangements tailor-made to cater to an individual’s specific travel needs while promoting a better quality of life. While the MaaS based literature largely assumes that the service will have a positive impact on individuals and society, it is important to note that there could also be unintended rebound impacts. Additionally, the evidence regarding the same is limited to estimations based on either a small number of pilot studies or a few stated preference studies and expert speculation. While studies have been conducted on the individual, organisational and societal level aspects of MaaS variants such as user preferences, service design, business models, energy impacts, operation and management etc. there seem to be a lack of holistic understanding of the potential impacts of these services from a system-level perspective. MaaS, as a hybrid innovation with the potential to transform socio-technical systems, is a combination of several actors at the individual, organisational and societal levels interacting in a shared arena with the goal to “lock-in” this innovation into the larger society. Therefore, there is a need to not only evaluate MaaS at these three levels but also to take an integrated, holistic approach to understand the system-level impacts of MaaS. As MaaS systems are not currently operating at their full potential, this thesis evaluates two real- life small-scale trials of MaaS in Stockholm, Sweden at the individual, organisational and societal levels to explore the complexities of MaaS and its variant services. Using the knowledge gathered from the evaluations of the two small-scale MaaS trials, this thesis then develops a system-level framework to evaluate MaaS and its variant services by integrating the individual, organizational and societal levels using economic, environmental and social dimensions. For MaaS stakeholders involved in the development, implementation, operation and management of full-scale MaaS, this framework could act as a helpful tool in decision-making processes by highlighting the complex relationships between and within the individual, organisational and societal levels and how the decisions made at the individual, organisational and societal levels could impact each other.
|
|
| 25. |
- Vaddadi, Bhavana, et al.
(författare)
-
Values of MaaS potential impacts based on Representative Scenarios
- 2020
-
Rapport (populärvet., debatt m.m.)abstract
- Mobility as a Service (MaaS) aims to facilitate seamless,intermodal travel, with the goal of providing a sustainable alternative to private car. Mobility as a Service (MaaS) is considered as one of the potential solutions for the sustainable transport sector.Public officials and practitioners have for several years sought assessments of the sustainability of MaaS for informed decisionmaking, governance and service design. This project has been conducted with the aim to provide reference values of MaaS potentials by evaluating its impacts on environmental, economic and social aspects through a selection of representative scenarios.The project has explored how and to what extent MaaS canlead to, for example, reduced emissions, reduced energy consumption, reduced private car usage and ownership, as well as reduced private car VKT (vehicle kilometre travelled). The knowledge generated from this project can support decision making within both public organisations and among service developers.
|
|
| 26. |
- Wei, Yixuan, et al.
(författare)
-
A review of data-driven approaches for prediction and classification of building energy consumption
- 2018
-
Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 82:1, s. 1027-1047
-
Tidskriftsartikel (refereegranskat)abstract
- A recent surge of interest in building energy consumption has generated a tremendous amount of energy data, which boosts the data-driven algorithms for broad application throughout the building industry. This article reviews the prevailing data-driven approaches used in building energy analysis under different archetypes and granularities, including those methods for prediction (artificial neural networks, support vector machines, statistical regression, decision tree and genetic algorithm) and those methods for classification (K-mean clustering, self-organizing map and hierarchy clustering). The review results demonstrate that the data-driven approaches have well addressed a large variety of building energy related applications, such as load forecasting and prediction, energy pattern profiling, regional energy-consumption mapping, benchmarking for building stocks, global retrofit strategies and guideline making etc. Significantly, this review refines a few key tasks for modification of the data-driven approaches in the context of application to building energy analysis. The conclusions drawn in this review could facilitate future micro-scale changes of energy use for a particular building through the appropriate retrofit and the inclusion of renewable energy technologies. It also paves an avenue to explore potential in macro-scale energy-reduction with consideration of customer demands. All these will be useful to establish a better long-term strategy for urban sustainability.
|
|
| 27. |
- Zhang, Xingxing, et al.
(författare)
-
Heat Pump Technologies and Their Applications in Solar Systems
- 2019
-
Ingår i: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation. - Cham : Springer. - 9783030172824 - 9783030172831 ; , s. 311-339
-
Bokkapitel (refereegranskat)abstract
- As the well known that global energy demand is on a trend of continuous growth, reducing energy demand and making good use of renewable energy are thought to be the major routes toward low carbon and sustainable future, in particular for the building sector. Compared to traditional gas-fired heating systems, heat pumps have been proved to be an energy-efficient heating technology which can save fossil fuel energy and consequently reduce CO2 emission. However, the most outstanding challenges for the application of heat pumps lie in their high demand for electrical power, and the insufficient heat transfer between the heat source and the refrigerant. To overcome these difficulties, a solar-assisted heat pump has been proposed to tackle these challenges. A solar-assisted heat pump combines a heat pump with a solar collector, enabling the use of solar energy to provide space heating and hot water for buildings. This chapter introduces heat pump technologies and their applications in solar systems. Two types of solar-assisted heat pump, direct and indirect expansion, are illustrated in details. This work has provided the fundamental research and experience for developing a solar heat pump system and contributing to a significant fossil fuel saving and carbon reduction in the global extent.
|
|
| 28. |
- Zhang, Xingxing, et al.
(författare)
-
Solar System Design and Energy Performance Assessment Approaches
- 2019
-
Ingår i: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation. - Cham : Springer. - 9783030172824 - 9783030172831 ; , s. 417-451
-
Bokkapitel (refereegranskat)abstract
- Recently, solar system has gained a rapid development in many countries because it is clean and sustainable. Many solar systems including the solar photovoltaic/loop-heat-pipe (PV/LHP), solar loop-heat-pipe (LHP), solar photovoltaic/micro-channel heat pipe (PV/MCHP) system, and solar thermal facade system (STF) have been designed for energy saving. To assess these systems’ performance, there are many approaches such as energy and exergy assessment which is used in this chapter to analyze their performance. Besides the system design, the authors set up dedicated experimental models in combination with computer models to test the systems’ performance. Furthermore, some systems are compared with the conventional system, and the performance of these solar systems is better than the conventional system. In addition, these solar systems are applied in many real buildings and their performance is examined, the results show that the solar systems have more potential to boost the building energy efficiency and create the possibility of solar development in buildings. © 2019, Springer Nature Switzerland AG.
|
|
| 29. |
- Zhang, Xingxing, et al.
(författare)
-
Solar Systems’ Economic and Environmental Performance Assessment
- 2019
-
Ingår i: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation. - Cham : Springer. - 9783030172824 - 9783030172831 ; , s. 453-486
-
Bokkapitel (refereegranskat)abstract
- The economic and environmental performance assessment of the solar system plays a critical role in building design, operation and retrofit. A dedicated economic model is necessary to assess the investment feasibility on a new technology, which allows investors to decide on a profitable investment, compare investment projects and know about the benefits of the best investment. An environmental model is adopted to predict carbon emission reduction in the solar system relative to the traditional heating and electronic systems. This chapter introduced three up-to-date solar system models and corresponding assessments related to their applications, including solar photovoltaic/loop heat pipe (PV/LHP) heat pump water heating system, loop heat pipe-based solar thermal facade (LHP-STF), heat pump water heating system as well as solar thermal facade (STF). The research results will be able to assist in decision-making in implementation of the proposed PV/T technology and analyses of the associated economic and environmental benefits, thus contributing to realization of regional and global targets on fossil fuel energy saving and environmental sustainability.
|
|
| 30. |
- Zhao, Xiaoyun, Ph.D., et al.
(författare)
-
An evaluation of the reliability of GPS-based transportation data
- 2017
-
Ingår i: Proceedings of IAC in Vienna 2017. - 9788088203049 ; , s. 323-334
-
Konferensbidrag (refereegranskat)abstract
- GPS-based data are becoming a cornerstone for real-time transportation applications. Tracking data of vehicles from GPS receivers are however susceptible to measurement errors. The assessment of the reliability of data from GPS receiver is a neglected issue, especially in a real road network setting and in the phase after data transfer but before information identification. An evaluation method is outlined and carried out by conducting a randomized experiment. We assess the reliability of GPS-based transportation data on geographical position, speed, and elevation from three varied receivers GlobalSat BT-338X, Magellan SporTrak Pro and smart phone for three transportation modes: bicycle, car, and bus. The positional error ranging from 0158 meters, and 74% to 100% with an error within 5 meters depending on the transportation mode and route, there is also a non-negligible risk for aberrant positioning. Speed is slightly underestimated or overestimated with errors around 5km/h except for SporTrak Pro which had an error of -10 km/h. Elevation measurements are unreliable with errors bigger than 100 meters.
|
|
| 31. |
- Zhao, Xiaoyun, et al.
(författare)
-
An Evaluation of the Reliability of GPS-Based Transportation Data
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- GPS-based data are becoming a cornerstone for real-time transportation applications. Tracking data of vehicles from GPS receivers are however susceptible to measurement errors. The assessment of the reliability of data from GPS receiver is a neglected issue, especially in a real road network setting and in the phase after data transfer but before information identification. An evaluation method is outlined and carried out by conducting a randomized experiment. We assess the reliability of GPS-based transportation data on geographical position, speed, and elevation from three varied receivers GlobalSat BT-338X, Magellan SporTrak Pro and smart phone for three transportation modes: bicycle, car, and bus. The positional error ranging from 0158 meters, and 74% to 100% with an error within 5 meters depending on the transportation mode and route, there is also a non-negligible risk for aberrant positioning. Speed is slightly underestimated or overestimated with errors around 5km/h except for SporTrak Pro which had an error
|
|
| 32. |
- Zhao, Xiaoyun, et al.
(författare)
-
Automated Vehicle Traffic Control Tower : A Solution to Support the Next Level Automation
- 2020
-
Ingår i: International Journal of Transport and Vehicle Engineering. - 1307-6892. ; 14:7, s. 283-293
-
Tidskriftsartikel (refereegranskat)abstract
- Automated vehicles (AVs) have the potential to enhance road capacity, improving road safety and traffic efficiency. Research and development on AVs have been going on for many years. However, when the complicated traffic rules and real situations interacted, AVs fail to make decisions on contradicting situations, and are not able to have control in all conditions due to highly dynamic driving scenarios. This limits AVs’ usage and restricts the full potential benefits that they can bring. Furthermore, regulations, infrastructure development, and public acceptance cannot keep up at the same pace as technology breakthroughs. Facing these challenges, this paper proposes automated vehicle traffic control tower (AVTCT) acting as a safe, efficient and integrated solution for AV control. It introduces a concept of AVTCT for control, management, decision- making, communication and interaction with various aspects in transportation. With the prototype demonstrations and simulations, AVTCT has the potential to overcome the control challenges with AVs and can facilitate AV reaching their full potential. Possible functionalities, benefits as well as challenges of AVTCT are discussed, which set the foundation for the conceptual model, simulation and real application of AVTCT.
|
|
| 33. |
- Zhao, Xiaoyun, et al.
(författare)
-
Does road network density matter in optimally locating facilities?
- 2015
-
Rapport (populärvet., debatt m.m.)abstract
- Optimal location on the transport infrastructure is the preferable requirement for many decision making processes. Most studies have focused on evaluating performances of optimally locate p facilities by minimizing their distances to a geographically distributed demand (n) when p and n vary. The optimal locations are also sensitive to geographical context such as road network, especially when they are asymmetrically distributed in the plane. The influence of alternating road network density is however not a very well-studied problem especially when it is applied in a real world context. This paper aims to investigate how the density level of the road network affects finding optimal location by solving the specific case of p-median location problem. A denser network is found needed when a higher number of facilities are to locate. The best solution will not always be obtained in the most detailed network but in a middle density level. The solutions do not further improve or improve insignificantly as the density exceeds 12,000 nodes, some solutions even deteriorate. The hierarchy of the different densities of network can be used according to location and transportation purposes and increase the efficiency of heuristic methods. The method in this study can be applied to other location-allocation problem in transportation analysis where the road network density can be differentiated.
|
|
| 34. |
- Zhao, Xiaoyun
(författare)
-
Government vs Market in Sustainable Residential Development? : Microdata analysis of car travel, CO2 emission and residence location
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increasing car usage and travel demands between residential locations and destinations in order to fulfill the various needs of residents is a primary cause of CO2 emissions. To win the battle against climate change, a better understanding of the question relating to which urban residential form may most effectively mitigate the CO2 emissions is the key pathway.This dissertation is concerned with the above problem and it mainly considers three objectives in providing insights on answering the question. The first objective is to comprehensively and microscopically understand intra-urban car travel behavior. The second objective is to estimate the induced CO2 emissions from daily intra-urban car travel and to ex-ante evaluate residential plans. The third objective is to assess whether the governmental sustainable residential development objective is aligned with the objectives of the estate market actors. To explore the research questions related to the objectives, a microdata analysis process (data collection, data assessment and transformation, data storage, data analysis and decision-making) is applied and is found essential in gaining access to key variables in exploring the answer of a preferable urban form. The dissertation offers many new solutions to various technical aspects through a microdata analysis process.The primary contribution of this dissertation is that it outlines an operational model that comprehensively integrates the investors’ investment strategy, the residents’ choice behavior, and the governmental sustainability objective in the interest of making an ex-ante assessment of residential plans. This ex-ante assessment provides decision-support in sustainable residential development at foremost local level.The first finding from the implementation of the model on the case study is that the market actors’ objectives are, in general, aligned with the government’s sustainable residential development objective. The second finding indicates that re-shaping the urban form into a compact city is preferable in mitigating CO2 emissions, in spite of the fact that the case city is of a polycentric urban form. These findings provide support for those advocating the compact city as the ideal for sustainable residential development, and also provide foresight on settling the answer to the preferred re-shaping of urban forms in climate change.
|
|
| 35. |
- Zhao, Xiaoyun, et al.
(författare)
-
How does the complexity of a road network affect optimal facility locations?
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The road network is a necessary component in transportation. It facilitiesspatial movements of people and goods, and it also influences the optimal locations of facilities that usually serve as destinations of the movements. To fulfill the transportation needs and to adapt to the facility development, the road network is often organized hierarchically and asymmetrically with various road levels and spatial structures. The complexity of the road network increases along with the increase of road levels and spatial structures. However, location models locate facilities on a given road network, usually the most complex one, and the influence from the complexity of road network in finding optimal locations is not well-studied. This paper aims to investigate how the complexity of a road network affects the optimal facility locations by applying the widely-applied p-median model. The main result indicates that an increase in road network complexity, up to a certain level, can obviously improve the solution, and the complexity beyond that level does not always lead to better solutions. Furthermore, the result is not sensitive to the choice of algorithms. In a specific case study, a detailed sensitivity analysis of algorithm and facility number further provides insight into computation complexity and location problems from intra-urban to inter-urban.
|
|
| 36. |
- Zhao, Xiaoyun, et al.
(författare)
-
Key barriers in MaaS development and implementation : Lessons learned from testing Corporate MaaS (CMaaS)
- 2020
-
Ingår i: Transportation Research Interdisciplinary Perspectives. - : Elsevier. - 2590-1982. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- To reach the full potential of Mobility as a Service (MaaS), especially its projected positive environmental impacts, the barriers to development and implementation processes must be identified. However, studies identifying such MaaS barriers are rare. Following an interdisciplinary approach, this paper aims to bridge this gap by adding knowledge on barriers to MaaS development and implementation using four perspectives (service design, business model, user travel attitude and behavior, and system impacts). Following a systems thinking approach, the barriers are investigated at three levels (individual, organizational and societal) to show their relationships. This paper investigates a specific type of MaaS, namely Corporate Mobility as a Service (CMaaS). The results obtained by investigating a large-scale CMaaS pilot provide implications of general barriers to MaaS development and implementation. The findings presented in this paper provide knowledge and guidance to MaaS stakeholders.
|
|
| 37. |
- Zhao, Xiaoyun, et al.
(författare)
-
Network density and the p-median solution
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The p-medianmodel is commonly used to find optimal locations of facilities for geographically distributed demands. So far, there are few studies that have considered the importance of the road network in the model. However, Han, Håkansson, and Rebreyend (2013) examined the solutions of the p-median model with densities of the road network varying from 500 to 70,000 nodes. They found as the density went beyond some 10,000 nodes, solutions have no further improvements but gradually worsen. The aim of this study is to check their findings by using an alternative heuristic being vertex substitution, as a complement to their using simulated annealing. We reject the findings in Han et al (2013). The solutions do not further improve as the nodes exceed 10,000, but neither do the solutions deteriorate.
|
|
| 38. |
- Zhao, Xiaoyun, et al.
(författare)
-
On assessing governmental sustainable residential planning and its alignment with residents’ and estate investors’ objectives
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- There are three key actors in forming the sustainable spatial distribution of residency in an area, (local) government, the estate investor and the resident, each with its own objective. Most urban planning studies have mainly focused on the ex-post evaluation of residential development by considering the objective of each actor separately. This paper outlines a conceptual model where the three key actors and their unique objectives are integrated with the aim of providing an ex-ante evaluation of residential development for government to make policies operational on a micro level. The methodology is implemented on a Swedish city, where sustainable residential development is in high need due to the influx of immigrants. The case study demonstrates that the model can integrate the macro and micro actors well. The model can provide noteworthy insights for the government on where the objectives of sustainability, livability and profit can be met. A sensitivity check of the parameter settings shows that the implementation of the model is robust for replication in other cities.
|
|
| 39. |
- Zhao, Xiaoyun
(författare)
-
On processing GPS tracking data of car-movements in Borlänge, Sweden
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The advancement of GPS technology enables GPS devices not only to be used as orientation and navigation tools, but also to track travelled routes. GPS tracking data provides essential information for a broad range of urban planning applications such as transportation routing and planning, traffic management and environmental control. This paper describes on processing the data that was collected by tracking the cars of 316 volunteers over a seven-week period. The detailed information is extracted. The processed data is further connected to the underlying road network by means of maps. Geographical maps are applied to check how the car-movements match the road network. The maps capture the complexity of the car-movements in the urban area. The results show that 90% of the trips on the plane match the road network within a tolerance.
|
|
| 40. |
- Zhao, Xiaoyun
(författare)
-
On processing GPS tracking data of spatiotemporal car movements : a case study
- 2015
-
Ingår i: Journal of Location Based Services. - : Informa UK Limited. - 1748-9725 .- 1748-9733. ; 9:4, s. 235-253
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The advancement of GPS technology has made it possible to use GPS devices as orientation and navigation tools, but also as tools to track spatiotemporal information. GPS tracking data can be broadly applied in location-based services, such as spatial distribution of the economy, transportation routing and planning, traffic management and environmental control. Therefore, knowledge of how to process the data from a standard GPS device is crucial for further use. Previous studies have considered various issues of the data processing at the time. This paper, however, aims to outline a general procedure for processing GPS tracking data. The procedure is illustrated step-by-step by the processing of real-world GPS data of car movements in Borlänge in the centre of Sweden.
|
|
| 41. |
- Zhao, Xiaoyun, 1990-, et al.
(författare)
-
Potential values of maas impacts in future scenarios
- 2021
-
Ingår i: Journal of Urban Mobility. - : Elsevier BV. - 2667-0917. ; 1, s. 100005-100005
-
Tidskriftsartikel (refereegranskat)abstract
- Mobility as a Service (MaaS) is considered a strategy that can provide potential solutions for a sustainable transport system. The current literature claims that MaaS can deliver net positive impacts for the transport system. However, whether these impacts are marginal or significant is unclear, as estimations typically are based on a few pilot tests. The lack of understanding of these impacts could create barriers for decision-making on policy and regulation in adopting MaaS strategy. The paper proposes a feasible evaluation to explore how and to what extent MaaS leads to, for example, reduced emissions, reduced fossil energy consumption, reduced car ownership and vehicle kilometres travelled on a large scale. The aim of this paper is to provide potential values of MaaS impacts based on analysis of future scenarios. The potential values of MaaS impacts can be used to support decision-making within both public organisations and among service developers for MaaS implementation and development.
|
|
| 42. |
- Zhao, Xiaoyun, et al.
(författare)
-
Reliability of GPS based traffic data: an experimental evaluation
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- GPS tracking of mobile objects provides spatial and temporal data for a broad range of applications including traffic management and control, transportation routing and planning. Previous transport research has focused on GPS tracking data as an appealing alternative to travel diaries. Moreover, the GPS based data are gradually becoming a cornerstone for real-time traffic management. Tracking data of vehicles from GPS devices are however susceptible to measurement errors – a neglected issue in transport research. By conducting a randomized experiment, we assess the reliability of GPS based traffic data on geographical position, velocity, and altitude for three types of vehicles; bike, car, and bus. We find the geographical positioning reliable, but with an error greater than postulated by the manufacturer and a non-negligible risk for aberrant positioning. Velocity is slightly underestimated, whereas altitude measurements are unreliable.
|
|
| 43. |
- Zhao, Xiaoyun, et al.
(författare)
-
Residential planning, driver mobility and CO2 emission
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In a city there are hotspots that attract the citizens and most of the transportation in the city arises when citizens move between their residence and the hotspots. However, the evaluation between energy-efficient mobility and urban residential planning has been found to be rather weak. In this paper, we propose an ex-ante evaluation method to quantify the impacts in terms of CO2 emissions induced by intra-urban car mobility due to different residential plans implemented at various urban areas. The method is illustrated by a Swedish midsize city which is presently preoccupied with urban planning of new residential areas in response to substantial population growth due to immigration. On average, the CO2 emissions increase from the continued urban core area (CUCA) to the suburban polycentric area (SPA) to the edge urbanization area (EUA), EUA is almost 3 times more than CUCA. The average travel distances also increase in the same sequence, the overall increase is more than 4 times. Apartment buildings could be more effective in meeting residential needs and mitigating CO2 emissions than dispersed single-family houses.
|
|
| 44. |
- Zhao, Xiaoyun, et al.
(författare)
-
Residential planning, driver mobility and CO2 emission : a microscopic look at Borlänge in Sweden
- 2017
-
Ingår i: European Planning Studies. - : Informa UK Limited. - 0965-4313 .- 1469-5944. ; 25:9, s. 1597-1614
-
Tidskriftsartikel (refereegranskat)abstract
- In a city there are hotspots that attract citizens, and most of the transportation arises when citizens move between their residence and primary destinations (i.e. hotspots). However, an ex ante evaluation of energy-efficient mobility and urban residential planning has seldom been conducted. Therefore, this paper proposes an ex ante evaluation method to quantify the impacts, in terms of CO2 emissions induced by intra-urban car mobility, of residential plans for various urban areas. The method is illustrated in a case study of a Swedish midsize city, which is presently preoccupied with urban planning of new residential areas in response to substantial population growth due to immigration. In general, CO2 emissions increase from the continued urban core area (CUCA), to the sub-polycentric area (SPA), to the edge urbanization area (EUA), where CO2 emission of EUA is twice that of the CUCA. The average travel distances also increase in the same pattern, though the relative increase is more than four times. Apartment buildings could be more effective in meeting residential needs and mitigating CO2 emissions than dispersed single-family houses.
|
|
| 45. |
- Zhao, Xiaoyun, Ph.D.
(författare)
-
Road network and GPS tracking with data processing and quality assessment
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- GPS technology has been embedded into portable, low-cost electronic devices nowadays to track the movements of mobile objects. This implication has greatly impacted the transportation field by creating a novel and rich source of traffic data on the road network. Although the promise offered by GPS devices to overcome problems like underreporting, respondent fatigue, inaccuracies and other human errors in data collection is significant; the technology is still relatively new that it raises many issues for potential users. These issues tend to revolve around the following areas: reliability, data processing and the related application.This thesis aims to study the GPS tracking form the methodological, technical and practical aspects. It first evaluates the reliability of GPS based traffic data based on data from an experiment containing three different traffic modes (car, bike and bus) traveling along the road network. It then outline the general procedure for processing GPS tracking data and discuss related issues that are uncovered by using real-world GPS tracking data of 316 cars. Thirdly, it investigates the influence of road network density in finding optimal location for enhancing travel efficiency and decreasing travel cost.The results show that the geographical positioning is reliable. Velocity is slightly underestimated, whereas altitude measurements are unreliable.Post processing techniques with auxiliary information is found necessary and important when solving the inaccuracy of GPS data. The densities of the road network influence the finding of optimal locations. The influence will stabilize at a certain level and do not deteriorate when the node density is higher.
|
|
| 46. |
- Zhao, Xiaoyun, et al.
(författare)
-
The dynamic and long-term changes of automated bus service adoption
- 2022
-
Ingår i: Transportation Research Part A. - : Elsevier BV. - 0965-8564 .- 1879-2375. ; 155, s. 450-463
-
Tidskriftsartikel (refereegranskat)abstract
- Integrating automated buses (ABs) into the public transport system may have potentials of providing more environment-friendly and cost-efficient mobility solutions by improving travel safety, reducing cost and decreasing congestion. However, the realization of the potentials depends not only on innovative technologies but also on users' acceptance of the ABs service. Whilst there has been a number of studies exploring the acceptance and adoption of ABs services, hardly any longitudinal studies have analyzed the long-term changes of individuals' behavior in adopting AB services. This paper aims to add knowledge on user acceptance of ABs in public transport based on empirical evidence in a real-life deployment context. Three waves of surveys that investigated users' travel attitudes and behaviors towards the automated bus were conducted at three different time points (six months, 11 months, and 14 months after the launch). The relationship between socio-demographic variables, travel experience variables, and attitude variables is modeled using structural equation modelling (SEM). Factors that influence experienced users to continue using the service were found to dynamically change over time. Initially, people were attracted to use the service if they perceived the information of the service to be sufficient, but they were demotivated to continue using the service if the comfort was worse, frequency was lower, or travel time was longer than expected. The results show that previous experience of adopting the ABs has impacts on different attitude variables. In order to promote individuals' continued use of ABs, the public transport authorities and operators should work closely to increase the frequency of the services. It is also necessary to enhance the comfort of the ABs.
|
|
