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- Abbas, Muhammad
(author)
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Requirements-Level Reuse Recommendation and Prioritization of Product Line Assets
- 2021
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Licentiate thesis (other academic/artistic)abstract
- Software systems often target a variety of different market segments. Targeting varying customer requirements requires a product-focused development process. Software Product Line (SPL) engineering is one possible approach based on reuse rationale to aid quick delivery of quality product variants at scale. SPLs reuse common features across derived products while still providing varying configuration options. The common features, in most cases, are realized by reusable assets. In practice, the assets are reused in a clone-and-own manner to reduce the upfront cost of systematic reuse. Besides, the assets are implemented in increments, and requirements prioritization also has to be done. In this context, the manual reuse analysis and prioritization process become impractical when the number of derived products grows. Besides, the manual reuse analysis process is time-consuming and heavily dependent on the experience of engineers.In this licentiate thesis, we study requirements-level reuse recommendation and prioritization for SPL assets in industrial settings. We first identify challenges and opportunities in SPLs where reuse is done in a clone-and-own manner. We then focus on one of the identified challenges: requirements-based SPL assets reuse and provide automated support for identifying reuse opportunities for SPL assets based on requirements. Finally, we provide automated support for requirements prioritization in the presence of dependencies resulting from reuse.
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| 3. |
- Abbaspour, Sara, 1984-
(author)
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Proposing Combined Approaches to Remove ECG Artifacts from Surface EMG Signals
- 2015
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Licentiate thesis (other academic/artistic)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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| 6. |
- Afshar, Sara
(author)
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Lock-Based Resource Sharing in Real-Time Multiprocessor Platforms
- 2014
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Licentiate thesis (other academic/artistic)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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| 7. |
- Afzal, Wasif
(author)
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Search-based approaches to software fault prediction and software testing
- 2009
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Licentiate thesis (other academic/artistic)abstract
- Software verification and validation activities are essential for software quality but also constitute a large part of software development costs. Therefore efficient and cost-effective software verification and validation activities are both a priority and a necessity considering the pressure to decrease time-to-market and intense competition faced by many, if not all, companies today. It is then perhaps not unexpected that decisions related to software quality, when to stop testing, testing schedule and testing resource allocation needs to be as accurate as possible. This thesis investigates the application of search-based techniques within two activities of software verification and validation: Software fault prediction and software testing for non-functional system properties. Software fault prediction modeling can provide support for making important decisions as outlined above. In this thesis we empirically evaluate symbolic regression using genetic programming (a search-based technique) as a potential method for software fault predictions. Using data sets from both industrial and open-source software, the strengths and weaknesses of applying symbolic regression in genetic programming are evaluated against competitive techniques. In addition to software fault prediction this thesis also consolidates available research into predictive modeling of other attributes by applying symbolic regression in genetic programming, thus presenting a broader perspective. As an extension to the application of search-based techniques within software verification and validation this thesis further investigates the extent of application of search-based techniques for testing non-functional system properties. Based on the research findings in this thesis it can be concluded that applying symbolic regression in genetic programming may be a viable technique for software fault prediction. We additionally seek literature evidence where other search-based techniques are applied for testing of non-functional system properties, hence contributing towards the growing application of search-based techniques in diverse activities within software verification and validation.
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| 8. |
- Agerskans, Natalie
(author)
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Digital Technologies for Enabling Smart Production : Examining the Aspects of Selection and Integration
- 2023
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Licentiate thesis (other academic/artistic)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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| 9. |
- Ahl, Linda, 1970-
(author)
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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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Licentiate thesis (other academic/artistic)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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| 10. |
- Ahlskog, Mats, 1970-
(author)
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Supporting pre-development of new manufacturing technologies
- 2015
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Licentiate thesis (other academic/artistic)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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