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- Jakobsson, Erik, 1987-
(författare)
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Data-driven Condition Monitoring in Mining Vehicles
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Situation awareness is a crucial capability of any autonomous system, including mining vehicles such as drill rigs and mine trucks. Typically situation awareness is interpreted as the capability of an autonomous system to interpret its surroundings and the intentions of other agents. The internal system awareness however, is often not receiving the same focus, even though the success of any given mission is completely dependent of the condition of the agents themselves. The internal system awareness in the form of vehicle health is the focus of this thesis.As the mining industry becomes increasingly automated, and vehicles become increasingly advanced, the need for condition monitoring and prognostics will continue to rise. This thesis explores data-driven methods that estimate the health of mining vehicles to accommodate those needs. We do so by utilizing available sensor signals, common on a large amount of mining vehicles, to make assessments of the current vehicle condition and tasks. The mining industry is characterized by small series of highly specialized vehicles, which affects the possibility to use more traditional prognostic solutions.The resulting health information can be used both to aid in tasks such as maintenance planning, but also as an important input to decision making for the planning system, i.e. how to run the vehicle for minimum wear and damage, while maintaining other mission objectives.The contributions include: a) A method to use operational data to estimate damage on the frame of a mine truck. This is done using system identification to find a model describing stresses in the structure with input from other sensors such as accelerometers, load sensors and pressure sensors. The estimated stress time signal is in turn used to calculate accumulated damage, and is shown to reveal interesting conclusions on driver behavior. b) A method to characterize the different driving tasks by using an accelerometer and a convolutional neural network. We show that the model is capable of classifying the vehicle task correctly in 96 % of the cases. And finally c), a system for underground road monitoring, where a quarter car model and a Kalman filter are used to generate an estimate of the road profile, while positioning the vehicle using inertial measurements and access point signal strength.
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| 2. |
- Angulo, Julio, 1980-
(författare)
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Usable privacy for digital transactions : Exploring the usability aspects of three privacy enhancing mechanisms
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The amount of personal identifiable information that people distribute over different online services has grown rapidly and considerably over the last decades. This has led to increased probabilities for identity theft, profiling and linkability attacks, which can in turn not only result in a threat to people’s personal dignity, finances, and many other aspects of their lives, but also to societies in general. Methods and tools for securing people’s online activities and protecting their privacy on the Internet, so called Privacy Enhancing Technologies (PETs), are being designed and developed. However, these technologies are often seen by ordinary users as complicated and disruptive of their primary tasks. In this licentiate thesis, I investigate the usability aspects of three main privacy and security enhancing mechanisms. These mechanisms have the goal of helping and encouraging users to protect their privacy on the Internet as they engage in some of the steps necessary to complete a digital transaction. The three mechanisms, which have been investigated within the scope of different research projects, comprise of (1) graphical visualizations of service providers’ privacy policies and user-friendly management and matching of users’ privacy preferences “on the fly”, (2) methods for helping users create appropriate mental models of the data minimization property of anonymous credentials, and (3) employing touch-screen biometrics as a method to authenticate users into mobile devices and verify their identities during a digital transaction. Results from these investigations suggest that these mechanisms can make digital transactions privacy-friendly and secure while at the same time delivering convenience and usability for ordinary users.
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| 3. |
- Karlsson, Anders, 1974-
(författare)
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Vilket religionskunskapsämne? : Ämneskonstruktioner i religionskunskap på gymnasiet med samtalsförhandlingar i centrum.
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis aims to describe one educational sequence in religious education. The study shows articulations and negotiations in the religious education classroom, as well as on digital discussion forums. Two questions are the core of the explorative case study. What is communicated between teachers and students in a Re-classroom in Sweden? How does the content of the communication contribute to constructing the Re-subject in two different discussion forums: digital and analogue? The case study follows an upper secondary school class, with 18 years old students, during one teaching sequence.The theoretical foundation is based in a social-cultural perspective. Data is produced by ethnographic methods and consist of classroom observations and interviews with teachers and students. For the interpretation of speech Even’s relief theory is used concerning what is said and Michel Bakhtin’s thoughts on speech genre concerning how it is expressed and negotiated in the teaching sequence.The analysis of the different forums show that in all of them, teachers and students tend to focus on what religious persons do, their appearance, and how they are limited by their faith. The religious persons are compared to a way of living according to a secular norm that the students find more relevant and up-to-date. When speaking of religious persons the students tend to express it in a derisive and disparaging way. Negotiations on content and framework factors interrupt the actual teaching in the classroom environment whilst digital forums are self-regulating and discussions quickly return to the topic after irrelevant digressions.In the discussion part of the thesis the various discussion forums are evaluated didactically. The impact of gender and framework factors on the student-teacher discussions is also raised. An additional question that is problematized is the tension between the curriculum of the subject and the teacher’s desire to get students interested in religion as a subject, described as ‘the teacher’s dilemma’. It is discussed whether this dilemma controls the teacher’s choice of subject.
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