| 1. |
- Abbaspour, Sara, 1984-
(författare)
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Proposing Combined Approaches to Remove ECG Artifacts from Surface EMG Signals
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Electromyography (EMG) is a tool routinely used for a variety of applications in a very large breadth of disciplines. However, this signal is inevitably contaminated by various artifacts originated from different sources. Electrical activity of heart muscles, electrocardiogram (ECG), is one of sources which affects the EMG signals due to the proximity of the collection sites to the heart and makes its analysis non-reliable. Different methods have been proposed to remove ECG artifacts from surface EMG signals; however, in spite of numerous attempts to eliminate or reduce this artifact, the problem of accurate and effective de-noising of EMG still remains a challenge. In this study common methods such as high pass filter (HPF), gating method, spike clipping, hybrid technique, template subtraction, independent component analysis (ICA), wavelet transform, wavelet-ICA, artificial neural network (ANN), and adaptive noise canceller (ANC) and adaptive neuro-fuzzy inference system (ANFIS) are used to remove ECG artifacts from surface EMG signals and their accuracy and effectiveness is investigated. HPF, gating method and spike clipping are fast; however they remove useful information from EMG signals. Hybrid technique and ANC are time consuming. Template subtraction requires predetermined QRS pattern. Using wavelet transform some artifacts remain in the original signal and part of the desired signal is removed. ICA requires multi-channel signals. Wavelet-ICA approach does not require multi-channel signals; however, it is user-dependent. ANN and ANFIS have good performance, but it is possible to improve their results by combining them with other techniques. For some applications of EMG signals such as rehabilitation, motion control and motion prediction, the quality of EMG signals is very important. Furthermore, the artifact removal methods need to be online and automatic. Hence, efficient methods such as ANN-wavelet, adaptive subtraction and automated wavelet-ICA are proposed to effectively eliminate ECG artifacts from surface EMG signals. To compare the results of the investigated methods and the proposed methods in this study, clean EMG signals from biceps and deltoid muscles and ECG artifacts from pectoralis major muscle are recorded from five healthy subjects to create 10 channels of contaminated EMG signals by adding the recorded ECG artifacts to the clean EMG signals. The artifact removal methods are also applied to the 10 channels of real contaminated EMG signals from pectoralis major muscle of the left side. Evaluation criteria such as signal to noise ratio, relative error, correlation coefficient, elapsed time and power spectrum density are used to evaluate the performance of the proposed methods. It is found that the performance of the proposed ANN-wavelet method is superior to the other methods with a signal to noise ratio, relative error and correlation coefficient of 15.53, 0.01 and 0.98 respectively.
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| 4. |
- Afshar, Sara
(författare)
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Lock-Based Resource Sharing in Real-Time Multiprocessor Platforms
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Embedded systems are typically resource constrained, i.e., resources such as processors, I/O devices, shared buffers or shared memory can be limited for tasks in the system. Therefore, techniques that enable an efficient usage of such resources are of great importance.In the industry, typically large and complex software systems are divided into smaller parts (applications) where each part is developed independently. Migration towards multiprocessor platforms has become inevitable from an industrial perspective. Due to such migration and to efficient use of system resources, these applications eventually may be integrated on a shared multiprocessor platform. In order to facilitate the integration phase of the applications on a shared platform, the timing and resource requirements of each application can be provided in an interface when the application is developed. The system integrator can benefit from such provided information in the interface of each application to ease the integration process. In this thesis, we have provided the resource and timing requirements of each application in their interfaces for applications that may need several processors to be allocated on when they are developed.Although many scheduling techniques have been studied for multiprocessor systems, these techniques are usually based on the assumption that tasks are independent, i.e. do not share resources other than the processors. This assumption is typically not true. In this thesis, we provide an extension to such systems to handle sharing of resources other than processor among tasks. Two traditional approaches exist for multiprocessor systems to schedule tasks on processors. A recent scheduling approach for multiprocessors has combined the two traditional approaches and achieved a hybrid more efficient approach compared to the two previous one. Due to the complex nature of this scheduling approach the conventional approaches for resource sharing could not be used straight forwardly. In this thesis, we have modified resource sharing approaches such that they can be used in such hybrid scheduling systems. A second concern is that enabling resource sharing in the systems can cause unpredictable delays and variations in response time of tasks which can degrade system performance. Therefore, it is of great significance to improve the resource handling techniques to reduce the effect of imposed delays caused by resource sharing in a multiprocessor platform. In this thesis we have proposed alternative techniques for resource handling that can improve system performance for special setups.
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| 5. |
- Agerskans, Natalie
(författare)
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Digital Technologies for Enabling Smart Production : Examining the Aspects of Selection and Integration
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With the development towards Industry 5.0, manufacturing companies are developing towards smart production. In smart production, data is used as a resource to interconnect different elements in the production system to learn and adapt to changing production conditions. Common objectives include human-centricity, resource-efficiency, and sustainable production. To enable these desired benefits of smart production, there is a need to use digital technologies to create and manage the entire flow of data. To enable smart production, it is essential to deploy digital technologies in a way so that collected raw data is converted into useful data that can be applied by equipment or humans to generate value or reduce waste in production. This requires consideration to the data flow within the production system, i.e., the entire process of converting raw data into useful data which includes data management aspects such as the collection, analysis, and visualization of data. To enable a good data flow, there is a need to combine several digital technologies. However, many manufacturing companies are facing challenges when selecting suitable digital technologies for their specific production system. Common challenges are related to the overwhelming number of advanced digital technologies available on the market, and the complexity of production system and digital technologies. This makes it a complex task to understand what digital technologies to select and the recourses and actions needed to integrate them in the production system.Against this background, the purpose of this licentiate thesis is to examine the selection and integration of digital technologies to enable smart production within manufacturing companies. More specifically, this licentiate thesis examines the challenges and critical factors of selecting and integrating digital technologies for smart production. This was accomplished by performing a qualitative-based multiple case study involving manufacturing companies within different industries and of different sizes. The findings show that identified challenges and critical factors are related to the different phases of the data value chain: data sources and collection, data communication, data processing and storage, and data visualisation and usage. General challenges and critical factors that were related to all phases of the data value chain were also identified. Moreover, the challenges and critical factors were related to people, process, and technology aspects. This shows that there is a need for holistic perspective on the entire data value chain and different production system elements when digital technologies are selected and integrated. Furthermore, there is a need to define a structured process for the selection and integration of digital technologies, where both management and operational level are involved.
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| 6. |
- Ahl, Linda, 1970-
(författare)
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Approaching Curriculum Resources : Examining the potential of textbooks and teacher guides to support mathematics learning and teaching
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The driving forces of conducting the two studies presented in this thesis are: the strong position of curriculum resources in the mathematics classroom in general; teachers’ faith in curriculum resources to convey the intentions and goals of mathematics education; and the expected benefits to mathematics education through expanding the knowledge base of research in the area of curriculum resources in general, and teacher guides in particular. This thesis builds upon two studies conducted in Sweden. The first is a study on how teachers use teacher guides. The results of this study could be seen as one piece in the building of a theoretical understanding of how teachers use their tools in planning and enacting teaching. The data for Study I were collected through semi-structured interviews with five early-years mathematics teachers. In advance, the teachers were asked to copy the pages from the teacher guide they had used the week before the interview. The analysis of the interviews shows that less experienced teachers desire a wider scope of content in their teacher guide. More experienced teachers desire support from teaching activities, in the design of teaching in classroom practice. Another interesting result was that all teachers in our study, regardless of prior experience, knowledge, beliefs, etc., want the teacher guide to offer connections between theory and practice. The second study investigates what content is represented in Swedish textbooks. The results of this study map the terrain over how the most commonly used textbooks in Sweden construct the topic of proportion and proportional reasoning. My choice of textbooks is based on a questionnaire among all compulsory school mathematics teachers in the sixth largest municipality in Sweden, revealing that two curriculum resources together covered 97% of the classrooms in Grades 7-9. The study provides insights into the strengths and weaknesses in the presented structure regarding proportional reasoning in the most commonly used textbooks in Swedish lower secondary school. Teachers could use these insights when making decisions about how to use their textbooks, and to possibly reconsider how to organize the enactment of the national curriculum in order to develop deep understanding. The analyses could provide authors of teacher guides and textbooks with valuable information to consider regarding structure and design.
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| 7. |
- Ahlskog, Mats, 1970-
(författare)
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Supporting pre-development of new manufacturing technologies
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In today’s tough industrial environment, efficient development of new products and new manufacturing solutions is necessary to stay competitive on a global market. Manufacturing companies use substantial money and development resources to develop new products. However, the resources spent on finding and implementing emerging manufacturing technologies are much more limited. This is often the case even though it is well known that a way of competing on a global market is through the introduction of new manufacturing technologies that can improve product quality as well as contribute to reducing manufacturing time, resulting in reduced product price and in the end increased profit.When introducing new manufacturing technologies, different challenges arise such as lack of knowledge, involvement of an external equipment supplier, etc. In addition, time-to-volume is critical when introducing new manufacturing technologies in a manufacturing context. To be able to have a fast ramp-up, manufacturing technology needs to be mature enough and at the same time meet all requirements. Efficient introduction of new manufacturing technologies requires that pre-development activities have been performed in advance.Previous research in this area highlights a lack of knowledge and solutions regarding pre-development of new manufacturing technologies. Such pre-development is important in order to have a successful introduction, fast time-to-volume and production system development. Based on these challenges, the objective of the research presented in this thesis is to develop support for pre-development of new manufacturing technologies.The research is based on literature reviews and three empirical case studies, carried out over a two-year period of time. The first empirical case study was an exploratory case study in the manufacturing industry. The purpose of that research study was to identify critical factors forcing manufacturing companies to improve the development of manufacturing technologies.The second study was a longitudinal embedded case study in the manufacturing industry with the purpose of identifying factors that affect evaluation of new manufacturing technologies during new product development. Particular attention was given to the product development process and how it has affected the evaluation of new manufacturing technologies.Finally, the third study was a single case study in the manufacturing industry with the purpose of analysing and discussing the assessment of the maturity level of a manufacturing technology.
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| 8. |
- Akbari, Keramatollah, 1961-
(författare)
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Impact of Radon Ventilation on Indoor Air Quality and Building Energy saving
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Industrial living is caused much people do live and work in closed and confined places; offices and residential buildings. This is why in this new world more fresh air which is generally provided by forced ventilation plays a vital role in living of human being. Furthermore because of many different indoor pollutants, like radon and artificial pollutants, the amount of fresh air and in turn the energy consumption has increased. This energy consumption related to ventilation has reached up to about 30 percent of energy used of building section. So making interaction between indoor air quality (IAQ) and optimization of energy saving is a necessary work. Radon as a natural pollutant is occurred in environment and in many countries threatens people health whereas is called the second causes of cancer. For reducing radon concentration in residential building at the acceptable level forced ventilation is used usually. Ventilation can improve IAQ but in the other side would increase the energy consumption in building sector and just now the contribution of ventilation exceeds up 50 percent of building sector's share. The aim of this thesis is to study the impact of ventilation on indoor radon by using Computational Fluid Dynamics (CFD) to achieve indoor air quality and energy efficiency. Application of CFD as a new technology, because of its cost and time savings, and on the other side, of its flexibility and precision is increasingly grown and can be used as a very important and valuable tool for the prediction and measurement of radon distribution in a ventilated building . Currently, measurement techniques and proposed standards and regulations of indoor pollutants and ventilation, particularly related to indoor radon cannot be able to provide a secure, safe and energy efficient indoor climate. This is why the indoor airflow distribution is very complex and with changing building geometry and operation condition, the treatment of air flow pattern, substantially would be changed, whereas the rules are usually independent of the buildings features. Furthermore, the indoor standards and regulations are based on average amount of pollutants in a room, whereas the pollutant distributions aren't identical and are varied throughout the room. Then the current techniques aren't so exactly valuable and acceptable. From different methods which is privilege to control pollutants, ventilation method is applicable in existing buildings. Designing effective ventilation can reduce radon concentration to very level low with regarding energy conservation remarks. This thesis presents results from simulation studies on ventilation and radon mitigation in residential buildings, in view points of indoor air quality and energy savings. The CFD technique is applied to predict, visualize and calculate of mixture radon-air flow. The distribution of indoor radon concentration, air velocity and room temperature also have considered together for achieving indoor air quality and energy saving. The results are also compared with the experimental data and related previous works. It was found that with increasing ventilation rate, the radon concentration is decreased, but the location of ventilation system is also important. From the simulation results, it is observed that within the ventilated room, there are some zones, which are good for living and somewhere is more polluted. The traditional radon detectors basically show the average value of radon content in 1m3 of air. That is why detector measuring is not exact and safe. Simulation results proved that floor heat can be supported ventilation effect and speed up the mixture movement. Floor heating reinforces the buoyancy effect, which is useful to reduce radon content in the floor (seating area) and then lower ventilation rate can be applied.
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| 9. |
- Andersson, Anna, 1974-
(författare)
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A framework supporting the collaboration between the logistics- and the product development process
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the competitive environment of today’s global markets, the demands of customers are increasing. They expect to get the best product at the lowest price with immediate availability. Logistics, including transportation, inventory maintenance, order processing, purchasing, warehousing, materials handling, packaging, customer service standards, and product scheduling must continuously be developed to meet the challenges of the market. The globalization, with longer distances to customers and suppliers, and the progressing trend of outsourcing are examples of why the importance of logistics has increased over the last few years.A considerable part of the final product cost is frozen during the early product development phases. In the early phases of the product development process, the cost of making design changes is low compared to making changes later in the product development process. The product development decisions made in the early phases of the product development process have considerable impact on future manufacturing and logistics activities as well.The objective of this research project is to develop a framework supporting the collaboration between the logistics- and the product development process. To do this, it has been essential to analyze which parameters influence the efficiency of the logistics process and the interface between the logistics- and the product development process. Also, to investigate how the logistics department can be integrated earlier in the product development process has been of interest. This has been done through both a theoretical review and also through a number of case studies.The result and conclusion of this project is a framework that gives support for what to focus on, how to collaborate, in which phases collaboration is meaningful, and which persons need to be involved in the different product development phases. Working as the framework suggests will, hopefully, give closer collaboration between the logistics- and the product development process than without this supportive framework. The expectation of the collaboration is an earlier integration of the logistics department in the product development process and through this influence and increase the efficiency of the logistics process.
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| 10. |
- Andersson, Carina, 1970-
(författare)
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Upplevelser av budskap : Fallstudier av hur användare upplever och förstår information i användargränssnitt
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- När användbarheten studeras av den information som presenteras i ett användargränssnitt på en datorskärm kan det framkomma vad som fungerar effektivt och korrekt. I sådana sammanhang förs sällan någon diskussion om hur den information som presenteras kommunicerar med en användare.Syftet med detta forskningsprojekt är att på ett generellt plan öka kunskapen om olika analytiska perspektiv för att studera den information som presenteras i ett användargränssnitt på en datorskärm, som ett led till att skapa begriplig information för människor. Mer preciserat är syftet att få en djupare förståelse för hur en informationslämnare kan kommunicera med en informationsanvändare genom den information som presenteras i ett användargränssnitt. Målet med forskningsprojektet är att presentera ett antal relevanta analytiska perspektiv som kan användas för att beskriva hur presenterad information i ett användargränssnitt kan kommunicera med en användare. Forskningsresultatet bidrar med ett ramverk som kan ligga till grund för ett analysstöd. Forskningsresultatet bidrar även med en ansats för framtida forskning inom området.Forskningsprojektet bygger på fyra fallstudier. Analysobjekten i fallstudierna utgörs av fyra olika användargränssnitt på datorskärm, vilka används inom olika myndigheter, organisationer och företag. Vartdera användargränssnittet och dess informationsdesign studeras med hänsyn till: informationslämnarnas önskemål och intentioner, informationsanvändarnas upplevelse och förståelse av information och kontexters påverkan.De slutsatser som dras är bland annat att informationsdesign i ett användargränssnitt på datorskärm upplevs och förstås av användare i samklang med inre, när och yttre kontext. Dessa kontexter kan studeras utifrån tre olika perspektiv, ett semiotiskt, ett retoriskt och ett narrativt perspektiv. En sådan analys kan framhäva den kommunikation som sker mellan de budskap som informationslämnaren vill berätta, hur den presenterade informationen i användargränssnittet arrangeras och komponeras och hur olika kontexter påverkar användarnas upplevelse och förståelse av den information som presenteras.
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