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- Gedda, Magnus, 1978-
(författare)
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Contributions to 3D Image Analysis using Discrete Methods and Fuzzy Techniques : With Focus on Images from Cryo-Electron Tomography
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With the emergence of new imaging techniques, researchers are always eager to push the boundaries by examining objects either smaller or further away than what was previously possible. The development of image analysis techniques has greatly helped to introduce objectivity and coherence in measurements and decision making. It has become an essential tool for facilitating both large-scale quantitative studies and qualitative research. In this Thesis, methods were developed for analysis of low-resolution (in respect to the size of the imaged objects) three-dimensional (3D) images with low signal-to-noise ratios (SNR) applied to images from cryo-electron tomography (cryo-ET) and fluorescence microscopy (FM). The main focus is on methods of low complexity, that take into account both grey-level and shape information, to facilitate large-scale studies. Methods were developed to localise and represent complex macromolecules in images from cryo-ET. The methods were applied to Immunoglobulin G (IgG) antibodies and MET proteins. The low resolution and low SNR required that grey-level information was utilised to create fuzzy representations of the macromolecules. To extract structural properties, a method was developed to use grey-level-based distance measures to facilitate decomposition of the fuzzy representations into sub-domains. The structural properties of the MET protein were analysed by developing a analytical curve representation of its stalk. To facilitate large-scale analysis of structural properties of nerve cells, a method for tracing neurites in FM images using local path-finding was developed. Both theoretical and implementational details of computationally heavy approaches were examined to keep the time complexity low in the developed methods. Grey-weighted distance definitions and various aspects of their implementations were examined in detail to form guidelines on which definition to use in which setting and which implementation is the fastest. Heuristics were developed to speed up computations when calculating grey-weighted distances between two points. The methods were evaluated on both real and synthetic data and the results show that the methods provide a step towards facilitating large-scale studies of images from both cryo-ET and FM.
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2. |
- Granlund, Anna, 1984-
(författare)
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Facilitating Automation Development in Internal Logistics Systems
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The internal logistics system includes all activities connected with managing the flow of materials within the physical limits of a facility. This system is an important part of operations in need of increased focus and continuous improvements. Automation is one possible tool with a previously confirmed great potential to improve internal logistics. Despite this great potential and a growing trend of using automation in the area, internal logistics activities are still not automated to the same extent as other parts of operations. The overall aim of this research is therefore to develop knowledge that supports the successful use of automation in internal logistics systems.The automation development process has been identified as critical for the success of the use of automation. With the overall aim of the research in mind, the objective of this thesis is to develop a framework facilitating the automation development process in internal logistics systems. To help fulfil the objective, empirical data have been collected through five case studies and a survey study. During the empirical studies, the process of improving the internal logistics system and the automation development process have been analysed and the focus has been on identifying challenges and facilitators for the successful use and development of automation in internal logistics systems.The findings indicate a poor awareness of both current and desired performance of the internal logistics system at the companies studied. In addition, automation development is often conducted in an unstructured and poorly supported manner and there is often insecurity regarding what steps and actions to take. Foremost, the findings indicate a poor base for proper evaluation and decisions during automation development in internal logistics systems. This is analysed and concluded as a cause of unclear goals and requirements and the lack of a strategic view with regard to both internal logistics operations and the use and development of automation.A framework, including proposed guidelines to overcome the observed challenges by including identified factors facilitating successful automation development in internal logistics systems has been developed. The core of the framework is a proposed process model for automation development in an internal logistics context. Due to the identified importance and the lack of a strategy linked to and supporting the automation development process, the framework also includes a proposed model for an internal logistics strategy as well as a proposed model for an automation strategy.
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