| 1. |
- Källhammer, Jan-Erik, et al.
(author)
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Near Zone Pedestrian Detection using a Low-Resolution FIR Sensor
- 2007
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In: Intelligent Vehicles Symposium, 2007 IEEE. - Istanbul, Turkey : IEEE. - 1424410673
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Conference paper (peer-reviewed)abstract
- This paper explores the possibility to use a single low-resolution FIR camera for detection of pedestrians in the near zone in front of a vehicle. A low resolution sensor reduces the cost of the system, as well as the amount of data that needs to be processed in each frame.We present a system that makes use of hot-spots and image positions of a near constant bearing to detect potential pedestrians. These detections provide seeds for an energy minimization algorithm that fits a pedestrian model to the detection. Since false alarms are hard to tolerate, the pedestrian model is then tracked, and the distance-to-collision (DTC) is measured by integrating size change measurements at sub-pixel accuracy, and the car velocity. The system should only engage braking for detections on a collision course, with a reliably measured DTC.Preliminary experiments on a number of recorded near collision sequences indicate that our method may be useful for ranges up to about 10m using an 80x60 sensor, and somewhat more using a 160x120 sensor. We also analyze the robustness of the evaluated algorithm with respect to dead pixels, a potential problem for low-resolution sensors.
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| 2. |
- Aldenlöv, Jens, et al.
(author)
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Public procurement of railway infrastructuremaintenance : a literature review
- 2017
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In: Proceedings of the 9th Nordic Conference on Construction Economics and Organization. - Lyngby : Polyteknisk Boghandel og Forlag. - 9788750211259 ; , s. 10-21
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Conference paper (peer-reviewed)abstract
- The maintenance of railway infrastructure has in several instances been changed from government-based to being based on public procurement, with varying degrees of flexibility for the contractor to design their maintenance work. The purpose of-giving contractors a larger freedom of choice of how to perform maintenance is to stimulate them to innovate and develop their maintenance processes. Since the contracts differ in between and there are changes in government policies over time that affects both existing and new contracts, a comparison between different contracts becomes challenging. A literature review has been conducted to understand the change in procurement strategy and how to encourage contractors to innovate. The research questions include: What procurement strategies are there? How is maintenance evaluated? How does procurement affect the innovation opportunities for entrepreneurs?The literature review focuses on railway maintenance and contract design between client and contractor. In total, 17 articles matched the search criteria and were selected for the review. To have successful maintenance service, five articles suggested partnering as a strategy with common goals in combination with good communication during the entirety of the contract. When selecting incentive plan, four articles mentions that a focus on performance-based incentives in combination with riskmanagement is better rather than actual payment schemes. The reason being that payment is often themain cause of conflicts between client and contractor. The scientific literature suggests that improvement in incentives improves quality of maintenance, decreases delays and technical failures. The conclusion from the literature review is that partnering in railway maintenance is considered successful. With accurate knowledge about railway assets the incentive plan becomes accurate which reduces costs.The literature review is a part of a research project with an overall goal to develop a model to guide the selection of appropriate type of procurement strategy, contract and control of maintenance for a moresustainable railway system.
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| 3. |
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| 4. |
- Candel, Melissa, 1994-, et al.
(author)
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Front-end value co-creation in housing development projects
- 2021
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In: Construction Management and Economics. - : Informa UK Limited. - 0144-6193 .- 1466-433X. ; 39:3, s. 245-260
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Journal article (peer-reviewed)abstract
- As a result of local governance, municipalities and housing developers work together to define housing development projects and to co-create value propositions. The purpose of this study is to explore how value propositions are co-created during the front-end of housing development projects and how this affects housing developers’ ability to drive change and innovation. The value co-creation process is explored through interviews, documents and observations in a case study of an urban development programme in Sweden. The findings illustrate how emerging conflicts and the process of resolving them are central drivers for value co-creation between these actors. However, conflicts that are not managed and resolved constructively can lead to the co-destruction of value. In this study we illustrate how value co-creation processes that precede procurement limit the flexibility of housing developers and determine the scope for value that can be realised.
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| 5. |
- Ekeskär, Andreas, 1984-, et al.
(author)
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Construction logistics in a multi-project context: coopetition among main contractors and the role of third-party logistics providers
- 2022
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In: Construction Management and Economics. - : Taylor & Francis. - 0144-6193 .- 1466-433X. ; 40:1, s. 25-40
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Journal article (peer-reviewed)abstract
- As a part of supply chain management (SCM) initiatives to improve performance and productivity in construction projects, the use of construction logistics setups (CLSs) operated by third-party logistics (TPL) providers have increased. CLSs are often used in complex multi-project contexts, such as urban development districts, where extensive coordination of actors, resources, and activities is needed. The purpose of this paper is twofold: to investigate how main contractors engage in horizontal relationships with each other when coordinating activities and resources within and across projects in a multi-project context, and to investigate what role a TPL provider assumes when engaging in relationships with main contractors in a multi-project context. The findings are based on a case study of an urban development district with a mandatory TPL-operated CLS, and we apply the industrial network approach. In this multi-project context, the main contractors engage in coopetitive relationships, coordinating activities and resources within and across projects. The TPL provider coordinates actors, resources, and activities, facilitating smoother production by managing logistics and mediating coopetitive relationships. This can be understood as a multi-project coordination role and extends the role SCM can play in construction. In that role, a TPL provider can minimise tensions between coopetitive actors across a multitude of horizontal relationships and projects.
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| 6. |
- Engström, Gunnar, et al.
(author)
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Pulmonary function and atherosclerosis in the general population : causal associations and clinical implications
- 2024
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In: European Journal of Epidemiology. - : Springer Nature. - 0393-2990 .- 1573-7284. ; 39:1, s. 35-49
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Journal article (peer-reviewed)abstract
- Reduced lung function is associated with cardiovascular mortality, but the relationships with atherosclerosis are unclear. The population-based Swedish CArdioPulmonary BioImage study measured lung function, emphysema, coronary CT angiography, coronary calcium, carotid plaques and ankle-brachial index in 29,593 men and women aged 50–64 years. The results were confirmed using 2-sample Mendelian randomization. Lower lung function and emphysema were associated with more atherosclerosis, but these relationships were attenuated after adjustment for cardiovascular risk factors. Lung function was not associated with coronary atherosclerosis in 14,524 never-smokers. No potentially causal effect of lung function on atherosclerosis, or vice versa, was found in the 2-sample Mendelian randomization analysis. Here we show that reduced lung function and atherosclerosis are correlated in the population, but probably not causally related. Assessing lung function in addition to conventional cardiovascular risk factors to gauge risk of subclinical atherosclerosis is probably not meaningful, but low lung function found by chance should alert for atherosclerosis.
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| 7. |
- Granheimer, Klara, et al.
(author)
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Adaptability in Public Procurement of Engineering Services Promoting Carbon Reduction: An Organizational Control Perspective
- 2022
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In: Sustainability. - : MDPI AG. - 2071-1050. ; 14:10, s. 5958-5958
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Journal article (peer-reviewed)abstract
- Many studies have emphasized the importance of engineering services and their adaptability to reduce carbon emissions in the construction sector. As public clients procure these services, selecting efficient (procurement-related) control modes is critical. However, studies of control modes and their effect on adaptability are scarce. The purpose of this study is to investigate how, through the choice of control modes, a public client may create incentives for service providers to deliver carbon reduction solutions in the construction phase. In this study, a procurement model and a classification model are developed, and a single case study of an engineering service contract aiming for carbon reduction is used to illustrate the models. The empirical data include 16 interviews with respondents from the 2 contract parties, i.e., the client and service provider. The findings show that it is important to create incentives for adaptability when procuring engineering services with the aim of reducing carbon emissions in the construction phase. The findings also highlight the importance of these incentives being created both in relation to the selection of service providers and to the responsibility between the contract parties. The models developed in the study may serve as important tools for both practitioners and researchers.
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| 8. |
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| 9. |
- Granheimer, Klara, 1989-
(author)
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Public procurement of engineering services : Task characteristics, control modes and effects on adaptability
- 2022
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Licentiate thesis (other academic/artistic)abstract
- Previous research has emphasized the importance of engineering services and adaptability in the early stages of construction projects. Public clients usually procure engineering services from private companies, which makes their procurement strategies important in creating incentives for adaptability and innovation for the service providers. Due to the high uncertainty and clients’ lack of understanding of the tasks they procure, the procurement of services is argued to be challenging – especially for public clients. Despite this, studies on the procurement of engineering services are scarce, as is research on the effects on adaptability. The purpose of this thesis, therefore, is to increase the understanding of organizational control in the public procurement of engineering services, by focusing on task characteristics, control modes and their effects on adaptability.A single case study of the Swedish Transport Administration was analyzed using the three models developed in the appended papers, i.e., the expanded control model, the procurement model for services and the classification model. The empirical data, consisting of interviews, observations and documents, were analyzed using visual mapping and flexible pattern matching.The findings illustrate that uncertainty is the task characteristic that differs between the early phase of construction (i.e., physical planning) and subsequent stages (i.e., tender document), while knowledge of the transformation process is the task characteristic that differs between a standard contract and an environmentally sustainable contract. Thus, when procuring engineering services including carbon reduction goals where new solutions are needed, new procurement strategies are necessary. In order to cope with the high uncertainty and low knowledge of the transformation process, social control is preferable. In addition, using social control will enhance the service providers’ willingness to adapt. These findings are important in the procurement of engineering services because uncertainty and the client’s understanding of the tasks are two of the main aspects that make engineering services difficult to procure.By combining task characteristics, control modes and their effects on adaptability, this thesis illustrates the importance of focusing on the entirety of organizational control. For example, even though process control and social control both incentivize the service provider to adapt to change, process control is less suitable for a public client when uncertainties are high. In addition, when choosing control modes related to the specification and reward system, it seems more efficient to provide the same incentives (i.e., process control may be combined with social control), whereas output control should not be combined with any other control mode. This shows the importance of combining the three variables and that the three main models of this thesis can be important tools. This knowledge and the models may therefore be useful to academics as well as practitioners. The results contribute to the scarce research on the procurement of engineering services for construction projects, as well as to the control literature.
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| 10. |
- Granheimer, Klara, et al.
(author)
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Public procurement of engineering services : Governance and control mechanisms
- 2021
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In: Proceedings of the 37th Annual ARCOM Conference, ARCOM 2021. - : Association of Researchers in Construction Management. ; , s. 470-479
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Conference paper (peer-reviewed)abstract
- Prior research has emphasized the importance of the early phases in construction projects. However, procuring engineering services for early phases is considered complex due to the high uncertainties and the information asymmetry favouring the service provider. This study explores public procurement of engineering services in the Swedish infrastructure sector, focusing on governance and control mechanisms. The purpose is to investigate the choice of governance and control mechanisms in engineering contracts from two perspectives, the public client's and the service providers. The findings are based on interviews with managers from the Swedish Transport Administration as well as from different engineering consulting companies. Findings indicate that the respondents from both sides seem to describe other choices and combinations of reward system and performance evaluation, compared to previous studies. This could be explained by the fact that the engineering contracts are less formalized than construction contracts in Sweden. This study shows that there are situations when clients have an information advantage in relation to their service suppliers and in-depth knowledge of the tasks procured, which affects the development of procurement strategies.
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