| 1. |
- Broberg Viklund, Sarah, 1983-
(författare)
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System studies of the use of industrial excess heat
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Energy, materials, and by-products, can be exchanged between companies, having positive effects in the form of improved resource efficiency, environmental benefits, and economic gains. One such energy stream that can be exchanged is excess heat, that is, heat generated as a by-product during, for example, industrial production. Excess heat will continue to play an important role in efforts to reduce greenhouse gas (GHG) emissions and improve energy efficiency. Using excess heat is therefore currently emphasized in EU policy as a way to reach EU climate targets.This thesis examines the opportunities of manufacturing industries to use industrial excess heat, and how doing so can positively affect industry, society, and the climate. Since different parts of the energy system are entangled, there is an inherent complexity in studying these systems and introducing excess heat in one part of the energy system may influence other parts of the system. This analysis has accordingly been conducted by combining studies from various perspectives, by applying both quantitative and qualitative methods and covering a broad range of aspects, such as technical possibilities as well as climate, policy, economics, and resource aspects.The results identify several opportunities and benefits accruing from excess heat use. Although excess heat is currently partly used as a thermal resource in district heating in Sweden, this thesis demonstrates that significant untapped excess heat is still available. The mapping conducted in the appended studies identifies excess heat in different energy carriers, mainly low-temperature water. Analysis of excess heat use in different recovery options demonstrated greater output when using excess heat in district heating than electricity production. Optimizing the trade-offs in excess heat used in a district heating network, heat-driven cooling, and electricity production under different energy market conditions while minimizing the system cost, however, indicated that the attractiveness of excess heat in district heating depends on the type of heat production in the system. Viewing excess heat as a low-cost energy source also makes it economically interesting, and creates opportunities to invest in excess heat-recovery solutions. Excess heat is often viewed as CO2 neutral since unused excess heat may be regarded as wasted energy. The GHG mitigation potential of using excess heat, however, was found to be ambiguous. The appended studies demonstrate that using excess heat for electricity production or for applications that reduce the use of electricity reduces GHG emissions. The effects of using excess heat in district heating, on the other hand, depend on the energy market development, for example, the marginal electricity production and marginal use of biomass, and on the type of district heating system replaced. The interviews performed reveal that energy policy does influence excess heat use, being demonstrated both to promote and discourage excess heat use. Beyond national energy policies, internal goals and core values were identified as important for improved energy efficiency and increased excess heat use.
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| 2. |
- Ekström, Veronica, 1975-
(författare)
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Det besvärliga våldet : Socialtjänstens stöd till kvinnor som utsatts för våld i nära relationer
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I avhandlingen analyseras hur våldsutsatta kvinnors behov tolkas, omförhandlas och anpassas för att kunna hanteras inom socialtjänstens organisation. Avhandlingens övergripande frågeställningar fokuserar på insatser och behov, betydelsen av socialtjänstens organisering och betydelsen av socialarbetarnas handlingsutrymme. Avhandlingen baseras på kvalitativa analyser av statliga propositioner, intervjuer med socialarbetare och med kvinnor som varit utsatta för våld i nära relationer. Det teoretiska ramverket bygger bland annat på Frasers (1989) teoretiska perspektiv som tar sin utgångspunkt i samhällets tolkningar av människors/gruppers behov av stöd, nyinstitutionell teori och teorier om gatubyråkrater. Avhandlingen visar att socialarbetares tolkningar är centrala aspekter av förhandlingen om hur våldsutsatta kvinnors behov och rätt till stöd ska förstås. Ett viktigt resultat i avhandlingen är att stödet till våldsutsatta kvinnor blir så pass olika. Avhandlingen ger inga svar i kvantitativa termer på hur olikheten är fördelad, men den ger exempel på hur olikheten tar sig uttryck. I kommuner där specialiseringen innebär att socialarbetarna på socialkontoret i första hand utreder behov och fattar beslut om insatser, måste det också finnas adekvata insatser att besluta om. Saknas det så erbjuds inte heller något stöd. Stödet till kvinnor som utsatts för våld i nära relationer blir också olika eftersom socialarbetare ställer olika krav eller sätter upp olika trösklar för att kvinnor ska få stöd. Avhandlingen visar att både gemensam kunskap och gemensam syn på sociala problem är centralt för att samarbetet inom den specialiserade socialtjänstens ska fungera och i längden också för vilket stöd människor kommer att erbjudas.
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| 3. |
- Angelov, Angel G., 1983-
(författare)
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Methods for interval-censored data and testing for stochastic dominance
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis includes four papers: the first three of them are concerned with methods for interval-censored data, while the forth paper is devoted to testing for stochastic dominance.In many studies, the variable of interest is observed to lie within an interval instead of being observed exactly, i.e., each observation is an interval and not a single value. This type of data is known as interval-censored. It may arise in questionnaire-based studies when the respondent gives an answer in the form of an interval without having pre-specified ranges. Such data are called self-selected interval data. In this context, the assumption of noninformative censoring is not fulfilled, and therefore the existing methods for interval-censored data are not necessarily applicable.A problem of interest is to estimate the underlying distribution function. There are two main approaches to this problem: (i) parametric estimation, which assumes a particular functional form of the distribution, and (ii) nonparametric estimation, which does not rely on any distributional assumptions. In Paper A, a nonparametric maximum likelihood estimator for self-selected interval data is proposed and its consistency is shown. Paper B suggests a parametric maximum likelihood estimator. The consistency and asymptotic normality of the estimator are proven.Another interesting problem is to infer whether two samples arise from identical distributions. In Paper C, nonparametric two-sample tests suitable for self-selected interval data are suggested and their properties are investigated through simulations.Paper D concerns testing for stochastic dominance with uncensored data. The paper explores a testing problem which involves four hypotheses, that is, based on observations of two random variables X and Y, one wants to discriminate between four possibilities: identical survival functions, stochastic dominance of X over Y, stochastic dominance of Y over X, or crossing survival functions. Permutation-based tests suitable for two independent samples and for paired samples are proposed. The tests are applied to data from an experiment concerning the individual's willingness to pay for a given environmental improvement.
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| 4. |
- Eliasson, Nina, 1965-
(författare)
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Att kommunicera skolans naturvetenskap : ett genusperspektiv på elevers deltagande i gemensam och enskild kommunikation
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Both individual and whole class communication of students are described in this thesis, which is based on a clear gender perspective. Two articles describe the participation of boys and girls in communication with the whole class, the empirical data collected consisting of videotaped lessons. The extent to which boys and girls participate in the communication is reported in the first study, and in the second the extent to which boys and girls respond to the teacher's closed or open questions about science is presented. The third study reports boys' and girls' individual communication when responding to written science questions. The summary chapter ties the results together from the perspective of Positioning Theory, making the thesis a result of Mixed Methods Research.Results show that boys participate in whole class communication more often than girls, with approximately the same level of dominance as shown in research from the early 80s. Boys also answer more questions than girls, the differences becoming apparent when teachers ask closed questions that can be answered in one or two words. In isolation, girls answer written questions to the same extent as boys, but give longer responses containing a more developed scientific language.Results showing that boys position themselves as knowledgeable more often than girls when teachers ask closed questions, are explained from the perspective of Positioning Theory. Girls more often position themselves as knowledgeable when teachers ask open questions that require reflection. In test situations, with time for reflection, the boys and girls position themselves as knowledgeable students to the same extent.Teachers need to be aware of the positioning attempts created by teaching, and consequently take into account that different approaches in teaching provide boys and girls with different access to the communication space.
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| 5. |
- Liu, Yu, 1991-
(författare)
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A Data-centric Internet of Things Framework Based on Public Cloud
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The pervasive application of Internet of Things (IoT) has been seen in many aspects in human daily life and industrial production. The concept of IoT originates from traditional machine-to-machine (M2M) communications which aimed at solving domain-specific and applicationspecific problems. Today, the rapid progress of communication technologies, the maturation of Internet infrastructures, the continuously reduced cost of sensors, and emergence of more open standards, have witnessed the approaching of the expected IoT era, which envisions full connectivity between the physical world and the digital world via the Internet protocol. The popularity of cloud computing technology has enhanced this IoT transform, benefiting from the superior computing capability and flexible data storage, let alone the security, reliability and scalability advantages.However, there are still a series of obstacles confronted by the industry in deployment of IoT services. First, due to the heterogeneity of hardware devices and application scenarios, the interoperability and compatibility between link-layer protocols, sub-systems and back-end services are significantly challenging. Second, the device management requires a uniform scheme to implement the commissioning, communication, authorization and identity management to guarantee security. Last, the heterogeneity of data format, speed and storage mechanism for different services pose a challenge to further data mining.This thesis aims to solve these aforementioned challenges by proposing a data-centric IoT framework based on public cloud platforms. It targets at providing a universal architecture to facilitate the deployment of IoT services in massive IoT and broadband IoT categories. The framework involves three representative communication protocols, namely WiFi, Thread and Lo-RaWAN, to enable support for local, personal, and wide area networks. A security assessment taxonomy for wireless communications in building automation networks is proposed as a tool to evaluate the security performance of adopted protocols, so as to mitigate potential network flaws and guarantee the security. Azure cloud platform is adopted in the framework to provide device management, data processing and storage, visualization, and intelligent services, thanks to the mature cloud infrastructure and the uniform device model and data model. We also exhibit the value of the study by applying the framework into the digitalization procedure of the green plant wall industry. Based on the framework, a remote monitoring and management system for green plant wall is developed as a showcase to validate the feasibility. Furthermore, three specialized visualization methods are proposed and a neuron network-based anomaly detection method is deployed in the project, showing the potential of the framework in terms of data analytics and intelligence.
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| 6. |
- Russell, Laurence
(författare)
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Exploring systematic lesson variation : A teaching method in mathematics
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The study presented in this licentiate thesis explores the student perception of systematically varied lessons, a specific lesson design and exploratory method of teaching mathematics in comprehensive school.Two 9th grade classes are taught in the curriculum defined mathematical core content sections of algebra and mathematical relationships and rate of change but by two different methods. One class is taught using a conventional textbook approach and the other with a series of systematically varied lessons; the first lesson containing instructions, lectures and individual textbook work, the second lesson containing exploratory, problem-solving worksheet tasks, same with manipulative materials, and with the third lesson containing presentation, reasoning and defending results and solutions from the second lesson. This is repeated over a four week period with three lessons a week. The classes then switch teaching methods fora second defined mathematical core content section. Both before and after applying the different teaching methods both classes perform tests for evaluation of content specific mathematical skills och answer questionnaires regarding their perception of learning. Comparisons of perceptions of the teaching methods and mathematical skills development are then evaluated. Results show minor changes of how the students perceive interest, enjoyment and anxiety, but an increased number of students that perceive stimulating learning settings during the systematically varied lesson method. Both classes show development of mathematical skills regardless of teaching methods. Results suggest influence in affective domains, as experiencing contentment, stimulating leaming settings and sense of learning increase during the systematically varied lessons method, and decrease correspondingly during the conventional method.The teaching methods, in the context of stimulating the desire to learn, and finding settings to stimulate
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