Thèses : « Information Enhancement »

1

Chen, Fangxin. « Speaker information enhancement ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22964.pdf.

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Ingram, Robert J. « Legibility enhancement for information visualisation ». Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307802.

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Sestok, Charles K. (Charles Kasimer). « Speech enhancement with spectral magnitude side information ». Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80117.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.
Includes bibliographical references (p. 43-44).
by Charles Kasimer Sestok, IV.
S.M.

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4

Burstein, Leah. « Legacy Student Information System : Replacement or Enhancement ? » Digital Commons at Loyola Marymount University and Loyola Law School, 2016. https://digitalcommons.lmu.edu/etd/376.

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Hiriyannaiah, Santosh. « Enhancement of information management capabilities in MDO framework ». Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1220473735/.

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Sezgin, Emre. « Itmem - Information Technology Management Enhancement Model : Assessment Of Information Technology Use In Organizations ». Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612353/index.pdf.

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This study proposes a new model for the assessment of information technology (IT) use in public and private companies, which is called ITMEM- Information Technology Management Enhancement Model. This model aims to assist decision making processes in information technology management. For this purpose, a tool is developed to explore strengths and weaknesses of a company in IT use. The model was developed upon a three-folded structure including (1) academic studies in technology management, (2) best practices which are developed for control over operations and processes including COBIT, CMMI and ITIL, and (3) standards about IT management and IT security. The conceptual framework of ITMEM is based on technology management process assessment model of M.J. Gregory. Methodological triangulation approach is adopted for the model for retrieving valid and reliable results. Triangulation consists of (1) semi structured interview, (2) presented company documents and (3) questionnaire developed upon relevant academic researches, best practices and standards. ITMEM was practiced on ten domestic and experienced companies in software &
development and manufacturing industries which were appraised in or in progress of being appraised in CMMI. The study revealed the benefits and deficiencies of IT use in the company. It also provided information for decision makers about IT value within companies, and demonstrated the effects of best practices and standards over IT use.The reported findings should be valuable assets to researchers studying on IT management and IT use in organizations.

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Wang, Lian, et 王漣. « Mining information from XML documents for query performance enhancement ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30497486.

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Gunturk, Bahadir K. « Multi-frame information fusion for image and video enhancement ». Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04072004-180015/unrestricted/gunturk%5Fbahadir%5Fk%5F200312%5Fphd.pdf.

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Mikkelä, Julius. « Should I Cyborg ? - A study into public opinion on Human Enhancement Technologies ». Thesis, Örebro universitet, Handelshögskolan vid Örebro Universitet, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-44369.

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Dabis, Homam Sabih. « The computer enhancement of speech signals ». Thesis, University of the West of Scotland, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304636.

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Alaei, Zohreh. « Power Enhancement in Piezoelectric Energy Harvesting ». Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188956.

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Piezoelectric energy harvesting has been around for almost a decade to generate power from the ambient vibrations. Although the generated power is very small, but there are several ways to increase and enhance the generated power. This project presents different methods of optimizing the output power by changing the structural configuration of the energy harvesters, selection of piezoelectric material and circuit interface of these harvesters. To understand the different steps of the enhancement, the process of energy conversion by piezoelectric material has been first looked at. Different groups of piezoelectric material were studied to see what kind of materials have the ability of increasing the generated power. As mechanical configuration of the energy harvesters has a significant effect on the output voltage, their configuration such as Cantilever beam type, Cymbal type and Circular diaphragms has been described and compared. After the power generated in the piezoelectric crystal , the current is sent to through an interface circuit to get rectified and regulated. This circuit can be modified to increase the power as well. There are several types of circuits that can increase the output voltage significantly. Synchronized Switch Harvesting (SSH) techniques, Synchronous Electric Charge Extraction technique and voltage doubler are such examples. These techniques have been also studied and compared. Because of the outgrowing industry of piezoelectric energy harvesting in Medical field, their function and their progress has also been reviewed.

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Murthy, Sindhu Dharani. « Ikriya : Simulating Software Quality Enhancement With Selected Replacement Policies ». TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1247.

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The quality of information systems in any organization helps to determine theefficiency of the organization. Many organizations maintain a custom software portfolio, whose quality is important to the organization. Management would like to optimize the portfolio’s quality. Decisions about software replacement or enhancement are made based on organizational needs and priorities. The development resources allocated help in determining the quality of new software, and should be put to optimal use. Enhancing existing software might sound cheap and easy but it is not always efficient. This thesis proposes a simulation model - iKriya - for this problem. It explores the consequences of various development and maintenance policies which might be applied.These depend on the state of existing software portfolio, the queue and properties of proposed projects, and the resources available. Optimal decisions are made by the simulator by taking the above mentioned factors into consideration.

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Wan, Wade K. (Wade Keith) 1973. « Adaptive format conversion information as enhancement data for scalable video coding ». Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/29903.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (p. 143-145).
Scalable coding techniques can be used to efficiently provide multicast video service and involve transmitting a single independently coded base layer and one or more dependently coded enhancement layers. Clients can decode the base layer bitstream and none, some or all of the enhancement layer bitstreams to obtain video quality commensurate with their available resources. In many scalable coding algorithms, residual coding information is the only type of data that is coded in the enhancement layers. However, since the transmitter has access to the original sequence, it can adaptively select different format conversion methods for different regions in an intelligent manner. This adaptive format conversion information can then be transmitted as enhancement data to assist processing at the decoder. The use of adaptive format conversion has not been studied in detail and this thesis examines when and how it can be used for scalable video compression. A new scalable codec is developed in this thesis that can utilize adaptive format conversion information and/or residual coding information as enhancement data. This codec was used in various simulations to investigate different aspects of adaptive format conversion such as the effect of the base layer, a comparison of adaptive format conversion and residual coding, and the use of both adaptive format conversion and residual coding.
(cont.) The experimental results show adaptive format conversion can provide video scalability at low enhancement bitrates not possible with residual coding and also assist residual coding at higher enhancement layer bitrates. This thesis also discusses the application of adaptive format conversion to the migration path for digital television. Adaptive format conversion is well-suited to the unique problems of the migration path and can provide initial video scalability as well as assist a future migration path.
by Wade K. Wan.
Ph.D.

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Chan, Ming-Yuen. « Quality enhancement and relation-aware exploration pipeline for volume visualization / ». View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CSED%202009%20CHANM.

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Stringer, Paul David. « Binaural signal processing for the enhancement of speech perception ». Thesis, University of York, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282296.

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Albathan, Mubarak Murdi M. « Enhancement of relevant features for text mining ». Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/90072/1/Mubarak%20Murdi%20M_Albathan_Thesis.pdf.

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With the explosion of information resources, there is an imminent need to understand interesting text features or topics in massive text information. This thesis proposes a theoretical model to accurately weight specific text features, such as patterns and n-grams. The proposed model achieves impressive performance in two data collections, Reuters Corpus Volume 1 (RCV1) and Reuters 21578.

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Cheng, Clara Michelle. « Self-reference in mystery moods consequences for information processing and self-enhancement / ». Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1147729556.

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Heese, Florian [Verfasser], Peter [Akademischer Betreuer] Vary et Rainer [Akademischer Betreuer] Martin. « Speech signal enhancement by information combining / Florian Heese ; Peter Vary, Rainer Martin ». Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130871509/34.

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Messina, Giuseppe. « Advanced Techniques for Image Analysis and Enhancement ». Thesis, Università degli Studi di Catania, 2011. http://hdl.handle.net/10761/190.

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The research activities, described in this thesis, have been mainly focused on images analysis and quality enhancement. Specifically the research regards the study and development of algorithms for color interpolation, contrast enhancement and red-eye removal, which have been exclusively oriented to mobile devices. Furthermore an images analysis for forgeries identification and image enhancement, usually directed by investigators (Forensic Image Processing) has been conducted. The thesis is organized in three main parts: Image Processing for Embedded Devices; Image Analysis and Enhancement; Forensics Image Processing.
Le attivita' di ricerca, descritte in questa tesi, sono state principalmente focalizzate sull'analisi delle immagini ed il miglioramento della qualita'. In particolare la ricerca riguarda lo studio e lo sviluppo di algoritmi di interpolazione del colore, miglioramento del contrasto e rimozione degli occhi rossi, che sono stati esclusivamente sviluppati per l'utilizzo su dispositivi "mobile". Inoltre e' stata documentata un analisi delle immagini per l'identificazione dei falsi e per il miglioramento della qualita' immagini, a fini investigativi (Forensics Image Processing). La tesi e' organizzata in tre parti: Image Processing for Embedded Devices; Image Analysis and Enhancement; Forensics Image Processing.

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Gustafsson, Fredrik. « Unsupervised Image Enhancement Using Generative Adversarial Networks : An attempt at real-time video enhancement ». Thesis, Uppsala universitet, Avdelningen för visuell information och interaktion, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-446698.

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As the world has become more connected meetings have moved online. However, since few have access to studio lighting and uses the embedded webcam the video quality can be far from good. Hence, there is an interest in using a software solution to enhance the video quality in real time. This thesis investigates the feasibility to train a machine learning model to automatically enhance the quality of images. The model must learn without using paired images, since it is difficult to capture images with the exact same content but different quality. Furthermore, the model has to process at least 30 images per second which is a common frequency for videos. Therefore, this thesis investigates the possibility to train a model without paired images and whether such a model can be used in real-time. To answer these questions several sizes of the same model was trained. These were evaluated using six different measures during in order to determine if training without paired data is possible. The models image enhancement capabilities and inference speed were investigated followed by attempts at improving the speed. Finally, different combinations of datasets were investigated to test how well the model generalised to new data. The results show that it is possible to train models for image enhancement without paired data. However, to use such a model in real time a graphics card is needed to reach above 30 images per second.

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Ebner, Hannes. « Collaborilla : An enhancement to the Conzilla concept browser for enabling collaboration ». Thesis, KTH, Computer and Systems Sciences, DSV, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4834.

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The research field Knowledge Management (KM) is about improving methods to structure and filter information. A concept browser makes it possible to navigate through complex information structures. Conzilla is such a concept browser. It is designed to present knowledge, to set concepts into relations to each other, and to make browsing through the resulting context-maps possible. Conzilla allows information and content being tied to concepts and concept-relations.

The collaboration facilities in Conzilla are limited. Basic elements such as a lookup mechanism and lifecycle information for information structures are missing. Before knowledge can be contributed, it is necessary to make sure that dependencies are fulfilled and the history of an edited object is obtained. This thesis is about providing these missing parts.

To be able to load a container, the information about the location of a component has to be held by a central registry. To resolve eventually existing dependencies, it is also necessary to register the components and its references. This thesis provides a design which eliminates the existing restrictions. The aim is to allow real collaboration through a remote services infrastructure, realized with Collaborilla. The theoretical background is discussed as well as a practical solution, including a prototype of a remote collaboration service.

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Okuyama, Junichi. « Study on conservation and enhancement of endangered sea turtles using animal behavioral information ». 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/135982.

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Cheng, Tik-sang Steve, et 鄭滌生. « Information technology for service enhancement in shopping mall : a case study of MegaBox ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42905436.

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Cheng, Tik-sang Steve. « Information technology for service enhancement in shopping mall a case study of MegaBox / ». Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42905436.

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Mei, Zhijie. « Computer-Aided Optically Scanned Document Information Extraction System ». Thesis, Mittuniversitetet, Institutionen för informationssystem och –teknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39190.

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This paper introduced a Computer-Aided Optically Scanned Document Information Extraction System. It could extract information including invoice No., issued date, buyer, etc., from the optically scanned document to meet the demand of customs declaration companies. The system output the structured information to a relational database. In detail, a software architecture for the information extraction of diverse-structure optically scanned document is designed. In this system, the original document is classified firstly. It would put into template-based extraction to improve the extraction performance if its template is pre-defined in the system. Then, a method for image enhancement to improve the image classification is proposed. This method aims to optimize the accuracy of neural network model by extracting the template-related feature and actively removing the unrelated feature. Lastly, the above system is implemented in this paper. This extraction are programed in Python which is a cross-platform languages. This system comprises three parts, classification module, template-based extraction and non-template extraction all of which have APIs and could be ran independently. This feature make this system flexible and easy to customization for the further demand. 445 real-world customs document images were input to evaluate the system. The result revealed that the introduced system ensured the diverse document support with non-template extraction and reached the overall high performance with template-based extraction showing the goal was basically achieved.

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Gupta, Pawan Kumar. « Throughput Enhancement of TCP over Wireless Links ». Thesis, Indian Institute of Science, 2002. http://hdl.handle.net/2005/48.

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The congestion control mechanisms of Transmission Control Protocol (TCP) are very effective in providing best effort service in wired networks, where packet losses are mainly due to congestion in the network. In wireless mobile networks, more often than not, loss of packets is because of corruption of data on the wireless link. The TCP sender responds to these losses as if they are due to congestion, by reducing its congestion window, thereby reducing the rate of flow of packets. The reduction in congestion window is a necessity when network is experiencing congestion to avoid congestion collapse but it is not required if packet losses occur due to corruption of data on the wireless link. This unnecessary reduction in congestion window for corruption losses is the main reason for poor throughput of data transfer in wireless networks. The reduction in congestion window for corruption losses can be avoided if TCP can successfully differentiate between packet losses due to congestion and corruption. We suggest enhancements to TCP that, if implemented, will help the TCP receiver in separately identifying corruption losses and congestion losses. The enhancements are suggested over and above standard TCP NewReno and we call this new scheme as "NewRenoEln (NewReno with Explicit Loss Notification)". We suggest that the TCP sender attach a separate checksum for the TCP header with the packet. Since the length of the TCP header is much smaller as compared to the length of the TCP packet, there is a large probability that the TCP receiver will receive the header portion of the TCP packet without error even if the data portion of the packet is corrupted. Once the header information is found to be correct for a corrupted packet, the receiver can generate reliable Explicit 5oss Notification (ELN) for the sender. We derive an expression for the probability of a receiver generating successful Explicit Loss Notification, assuming a generic link layer protocol that is used for data transfer over wireless link. With this analysis, we show that there is large probability that receiver will generate successful ELN for various channel conditions We also suggest modifications to the sender behavior on receiving successful Explicit Loss Notification from the receiver. With these modifications, the TCP sender will recover from corruption losses without any reduction in congestion window. There is also a need to develop a unified analytical approach for the evaluation of TCP performance. We develop an analytical approach for the performance evaluation of NewRenoEln scheme. We compare the throughput results obtained by analytical calculations with results obtained by simulation and find them to be very close to each other. We also compare the performance of the proposed scheme NewRenoEln and the standard NewReno TCP via simulation as well as analytical approach, and find considerable improvement in throughput over wireless links.

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Wrench, Alan A. « Techniques for the enhancement of linear predictive speech coding in adverse conditions ». Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/14709.

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Thornbrue, James R. (James Raymond) 1976. « Adaptive format conversion information as enhancement data for the high-definition television migration path ». Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29618.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.
Includes bibliographical references (p. 115-116).
Prior research indicates that a scalable video codec based on adaptive format conversion (AFC) information may be ideally suited to meet the demands of the migration path for high-definition television. Most scalable coding schemes use a single format conversion technique and encode residual information in the enhancement layer. Adaptive format conversion is different in that it employs more than one conversion technique. AFC partitions a video sequence into small blocks and selects the format conversion filter with the best performance in each block. Research shows that the bandwidth required for this type of enhancement information is small, yet the improvement in video quality is significant. This thesis focuses on the migration from 10801 to 1080P using adaptive deinterlacing. Two main questions are answered. First, how does adaptive format conversion perform when the base layer video is compressed in a manner typical to high-definition television? It was found that when the interlaced base layer was compressed to 0.3 bpp, the mean base layer PSNR was 32 dB and the PSNR improvement due to the enhancement layer was as high as 4 dB. Second, what is the optimal tradeoff between base layer and enhancement layer bandwidth? With the total bandwidth fixed at 0.32 bpp, it was found that the optimal bandwidth allocation was about 96% base layer, 4% enhancement layer using fixed, 16x16 pixel partitions. The base and enhancement layer video at this point were compared to 100% base layer allocation and the best nonadaptive format conversion. While there was usually no visible difference in base layer quality, the adaptively deinterlaced enhancement layer was generally sharper, with cleaner edges, less flickering, and fewer aliasing artifacts than the best nonadaptive method. Although further research is needed, the results of these experiments support the idea of using adaptive deinterlacing in the HDTV migration path.
by James R. Thornbrue.
S.M.

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Jao, Irwin Yui-Wen. « Capability enhancement through cross-border contract manufacturing alliances : a study of Taiwanese information technology firms ». Thesis, London Business School (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244179.

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Ahram, Tareq Z. « Information retrieval performance enhancement using the average standard estimator and the multi-criteria decision weighted set of performance measures ». Orlando, Fla. : University of Central Florida, 2008. http://purl.fcla.edu/fcla/etd/CFE0002426.

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Kühnapfel, Thorsten. « Audio networks for speech enhancement and indexing ». Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/206.

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For humans, hearing is the second most important sense, after sight. Therefore, acoustic information greatly contributes to observing and analysing an area of interest. For this reason combining audio and video cues for surveillance enhances scene understanding and the observed events. However, when combining different sensors their measurements need to be correlated, which is done by either knowing the exact relative sensor alignment or learning a mapping function. Most deployed systems assume a known relative sensor alignment, making them susceptible to sensor drifts. Additionally, audio recordings are generally a mixture of several source signals and therefore need to be processed to extract a desired sound source, such as speech of a target person.In this thesis a generic framework is described that captures, indexes and extracts surveillance events from coordinated audio and video cues. It presents a dynamic joint-sensor calibration approach that uses audio-visual sensor measurements to dynamically and incrementally learn the calibration function, making the sensor calibration resilient to independent drifts in the sensor suite. Experiments demonstrate the use of such a framework for enhancing surveillance.Furthermore, a speech enhancement approach is presented based on a distributed network of microphones, increasing the effectiveness for acoustic surveillance of large areas. This approach is able to detect and enhance speech in the presence of rapidly changing environmental noise. Spectral subtraction, a single channel speech enhancement approach, is modified to adapt quickly to rapid noise changes of two common noise sources by incorporating multiple noise models. The result of the cross correlation based noise classification approach is also utilised to improve the voice activity detection by minimising false detection based on rapid noise changes. Experiments with real world noise consisting of scooter and café noise have proven the advantage of multiple noise models especially when the noise changes during speech.The modified spectral subtraction approach is then extended to real world scenarios by introducing more and highly non-stationary noise types. Thus, the focus is directed to implement a more sophisticated noise classification approach by extracting a variety of acoustic features and applying PCA transformation to compute the Mahalanobis distance to each noise class. This distance measurement is also included in the voice activity detection algorithm to reduce false detection for highly non-stationary noise types. However, using spectral subtraction in non-stationary noise environments, such as street noise, reduces the performance of the speech enhancement. For that reason the speech enhancement approach is further improved by using the sound information of the entire network to update the noise model of the detected noise type during speech. This adjustment considerably improved the speech enhancement performance in non-stationary noise environments. Experiments conducted under diverse real world conditions including rapid noise changes and non-stationary noise sources demonstrate the effectiveness of the presented method.

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Yanar, Tahsin Alp. « The Enhancement Of The Cell-based Gis Analyses With Fuzzy Processing Capabilities ». Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1223304/index.pdf.

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In order to store and process natural phenomena in Geographic Information Systems (GIS) it is necessary to model the real world to form computational representation. Since classical set theory is used in conventional GIS software systems to model uncertain real world, the natural variability in the environmental phenomena can not be modeled appropriately. Because, pervasive imprecision of the real world is unavoidably reduced to artificially precise spatial entities when the conventional crisp logic is used for modeling. An alternative approach is the fuzzy set theory, which provides a formal framework to represent and reason with uncertain information. In addition, linguistic variable concept in a fuzzy logic system is useful for communicating concepts and knowledge with human beings. In this thesis, a system to enhance commercial GIS software, namely ArcGIS, with fuzzy set theory is designed and implemented. The proposed system allows users to (a) incorporate human knowledge and experience in the form of linguistically defined variables into GIS-based spatial analyses, (b) handle impreiii cision in the decision-making processes, and (c) approximate complex ill-defined problems in decision-making processes and classification. The operation of the proposed system is presented through case studies, which demonstrate its application for classification and decision-making processes. This thesis shows how fuzzy logic approach may contribute to a better representation and reasoning with imprecise concepts, which are inherent characteristics of geographic data stored and processed in GIS.

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AHRAM, TAREQ. « INFORMATION RETRIEVAL PERFORMANCE ENHANCEMENT USING THE AVERAGE STANDARD ESTIMATOR AND THE MULTI-CRITERIA DECISION WEIGHTED SET ». Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3280.

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Information retrieval is much more challenging than traditional small document collection retrieval. The main difference is the importance of correlations between related concepts in complex data structures. These structures have been studied by several information retrieval systems. This research began by performing a comprehensive review and comparison of several techniques of matrix dimensionality estimation and their respective effects on enhancing retrieval performance using singular value decomposition and latent semantic analysis. Two novel techniques have been introduced in this research to enhance intrinsic dimensionality estimation, the Multi-criteria Decision Weighted model to estimate matrix intrinsic dimensionality for large document collections and the Average Standard Estimator (ASE) for estimating data intrinsic dimensionality based on the singular value decomposition (SVD). ASE estimates the level of significance for singular values resulting from the singular value decomposition. ASE assumes that those variables with deep relations have sufficient correlation and that only those relationships with high singular values are significant and should be maintained. Experimental results over all possible dimensions indicated that ASE improved matrix intrinsic dimensionality estimation by including the effect of both singular values magnitude of decrease and random noise distracters. Analysis based on selected performance measures indicates that for each document collection there is a region of lower dimensionalities associated with improved retrieval performance. However, there was clear disagreement between the various performance measures on the model associated with best performance. The introduction of the multi-weighted model and Analytical Hierarchy Processing (AHP) analysis helped in ranking dimensionality estimation techniques and facilitates satisfying overall model goals by leveraging contradicting constrains and satisfying information retrieval priorities. ASE provided the best estimate for MEDLINE intrinsic dimensionality among all other dimensionality estimation techniques, and further, ASE improved precision and relative relevance by 10.2% and 7.4% respectively. AHP analysis indicates that ASE and the weighted model ranked the best among other methods with 30.3% and 20.3% in satisfying overall model goals in MEDLINE and 22.6% and 25.1% for CRANFIELD. The weighted model improved MEDLINE relative relevance by 4.4%, while the scree plot, weighted model, and ASE provided better estimation of data intrinsic dimensionality for CRANFIELD collection than Kaiser-Guttman and Percentage of variance. ASE dimensionality estimation technique provided a better estimation of CISI intrinsic dimensionality than all other tested methods since all methods except ASE tend to underestimate CISI document collection intrinsic dimensionality. ASE improved CISI average relative relevance and average search length by 28.4% and 22.0% respectively. This research provided evidence supporting a system using a weighted multi-criteria performance evaluation technique resulting in better overall performance than a single criteria ranking model. Thus, the weighted multi-criteria model with dimensionality reduction provides a more efficient implementation for information retrieval than using a full rank model.
Ph.D.
Department of Industrial Engineering and Management Systems
Engineering and Computer Science
Industrial Engineering PhD

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Somi, Ntombizodwa Getrude. « The role played by academic libraries in the enhancement of information literacy : a study of Fort Hare library ». Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/7956.

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Includes bibliographical references (leaves 110-122).
Many technological challenges today require libraries and various stakeholders to embark on student learning and empower students with the necessary information skills to function efficiently and effectively in the global information age. The aim of this study was to investigate the role played by the University of Fort Hare Library in the enhancement of information literacy. A survey method was selected. Findings and recommendations from students, the lessons of information literacy at the University Fort Hare library and other libraries are presented. Recommendations about what the library needs to do to empower students for lifelong learning is also presented.

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Xing, Luo Oscar. « Deep Learning for Speech Enhancement : A Study on WaveNet, GANs and General CNN-RNN Architectures ». Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-260351.

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Clarity and intelligiblity are important aspects of speech, especially in a time of misinformation and mistrust. The breakthrough in generative models for audio files has brought massive improvements for speech enhancement. Google’s WaveNet architecture has been modified for noise reduction in a model called WaveNet denoising and has proven to be state-of-the-art. Another competitor on the market would be the Speech Enhancement Generative Adversarial Network (SEGAN) which adapts the GAN architecture into applications on speech. While most older models focus on feature extraction and spectrogram analysis, these two models attempt to skip those steps and become end-to-end models completely. While end-to-end is good, data preprocessing is still a valuable asset to consider. A network designed by Microsoft Research called EHNet uses the spectrogram data as input instead of the mere 1D waveforms to capture more relations between datapoints as a higher dimension can enable more information. This thesis aims to explore the speech enhancement field of study from a deep learning perspective and focus on the three mentioned architectures in theory dissection and results from new datasets. There is also an implementation of the Wiener filter as a benchmark. We arrive at the conclusion that all three networks are viable in the task of enhancing speech, however SEGAN performed better on our dataset and was more robust to new data in comparison. For future work one could improve the evaluation methods, change datasets and implement hyperparameter optimization for further comparative analysis.
Klarhet och förståelse är viktiga aspekter av tal, särskilt i en tid då falsk information och misstrogenhet är vanligt. Genombrottet för generativa modeller inom ljud har medfört stora förbättringar inom talsignalförbättring. Googles WaveNet-arkitektur har modifierats för brusreducering i en modell som kallas för WaveNet-denoising vilket har visat goda resultat. En annan konkurrent på marknaden är den generella adversariella nätverket för talsignalförbättring (SEGAN) som anpassar GAN-arkitekturen till tillämpningar på tal. Medan de flesta äldre modeller fokuserar på särdragsextraktion och spektrogramanalys, så försöker de två nya modellerna med att ignorera dessa koncept och vara end-to-end istället. Medan end-to-end är bra är databehandling fortfarande en viktig aspekt som är värdefull att överväga. Ett nätverk som designats av Microsoft Research heter EHNet och använder spektrogramdata som input istället för enbart 1D-vågformer för att fånga upp fler relationer mellan datapunkter, då högre dimensioner möjliggör mer information. Detta examensarbete syftar till att utforska studieområdet inom talsignalförbättring samt utreda de tre nämnda arkitekturerna genom teoretisk undersökning och resultat på nya dataset. Det kommer också vara en implementering av Wienerfilter som riktmärke för resultaten. Vi kommer fram till slutsatsen att alla tre nätverk är möjliga alternativ inom talsignalförbättring men SEGAN är den bästa modellen när det kommer till resultat på vårt specifika dataset och med avseende på robusthet. För framtida arbeten kan man förbättra utvärderingsmetoderna, ändra datasetet och implementera hyperparameteroptimeringför ytterligare jämförande analyser.

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Swarlis, Linda L. « Enhancement of spatial ability in girls in a single-sex environment through spatial experience and the impact on information seeking ». Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9734/.

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The test scores of spatial ability for women lag behind those of men in many spatial tests. On the Mental Rotations Test (MRT), a significant gender gap has existed for over 20 years and continues to exist. High spatial ability has been linked to efficiencies in typical computing tasks including Web and database searching, text editing, and computer programming. The relationships between the components of visuospatial ability and performance are complex. However, research strongly indicates that a connection exists, and further research is necessary to determine the interactions between the variables of environment, genetics, and spatial training. Spatial experience can enhance spatial skills. However, to what extent spatial skills can be enhanced in female adolescents through a spatial curriculum to reduce the gap in scores has not been fully researched, nor has the impact of spatial skill on information seeking. This research project investigated spatial skill in adolescent females by examining (1) the extent to which the intervention of teaching a spatial curriculum in a single-sex setting could improve mental rotation test scores, and (2) the impact of spatial skills on an information seeking task in a single-sex setting. The extent to which a spatial visualization curriculum can improve MRT scores from a pretest to a posttest for girls was the first factor examined using a spatial visualization curriculum. The information seeking task used 4 tasks from a doctoral study and utilized the scholarly journal database JSTOR® (JSTOR, Ann Arbor, MI, www.jstor.org).

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Richardson, Richard Thomas. « Image Enhancement of Cancerous Tissue in Mammography Images ». NSUWorks, 2015. http://nsuworks.nova.edu/gscis_etd/39.

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This research presents a framework for enhancing and analyzing time-sequenced mammographic images for detection of cancerous tissue, specifically designed to assist radiologists and physicians with the detection of breast cancer. By using computer aided diagnosis (CAD) systems as a tool to help in the detection of breast cancer in computed tomography (CT) mammography images, previous CT mammography images will enhance the interpretation of the next series of images. The first stage of this dissertation applies image subtraction to images from the same patient over time. Image types are defined as temporal subtraction, dual-energy subtraction, and Digital Database for Screening Mammography (DDSM). Image enhancement begins by applying image registration and subtraction using Matlab 2012a registration for temporal images and dual-energy subtraction for dual-energy images. DDSM images require no registration or subtraction as they are used for baseline analysis. The image data are from three different sources and all images had been annotated by radiologists for each image type using an image mask to identify malignant and benign. The second stage involved the examination of four different thresholding techniques. The amplitude thresholding method manipulates objects and backgrounds in such a way that object and background pixels have grey levels grouped into two dominant and different modes. In these cases, it was possible to extract the objects from the background using a threshold that separates the modes. The local thresholding introduced posed no restrictions on region shape or size, because it maximized edge features by thresholding local regions separately. The overall histogram analysis showed minima and maxima of the image and provided four feature types--mean, variance, skewness, and kurtosis. K-means clustering provided sequential splitting, initially performing dynamic splits. These dynamic splits were then further split into smaller, more variant regions until the regions of interest were isolated. Regional-growing methods used recursive splitting to partition the image top-down by using the average brightness of a region. Each thresholding method was applied to each of the three image types. In the final stage, the training set and test set were derived by applying the four thresholding methods on each of the three image types. This was accomplished by running Matlab 2012a grey-level, co-occurrence matrix (GLCM) and utilizing 21 target feature types, which were obtained from the Matlab function texture features. An additional four feature types were obtained from the state of the histogram-based features types. These 25 feature types were applied to each of the two classifications malignant and benign. WEKA 3.6.10 was used along with classifier J48 and cross-validation 10 fold to find the precision, recall, and f-measure values. Best results were obtained from these two combinations: temporal subtraction with amplitude thresholding, and temporal subtraction with regional-growing thresholding. To summarize, the researcher's contribution was to assess the effectiveness of various thresholding methods in the context of a three-stage approach, to help radiologists find cancerous tissue lesions in CT and MRI mammography images.

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Chawan, Akshay. « Security Enhancement of Over-The-Air Update for Connected Vehicles ». University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1533246722910754.

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Stuhr, Lina. « Grain Reduction in Scanned Image Sequences under Time Constraints ». Thesis, Linköping University, Department of Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17577.

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This thesis is about improving the image quality of image sequences scanned by the film scanner GoldenEye. Film grain is often seen as an artistic effect in film sequences but scanned images can be more grainy or noisy than the intention. To remove the grain and noise as well as sharpen the images a few known image enhancement methods have been implemented, tested and evaluated. An own idea of a thresholding method using the dyadic wavelet transform has also been tested. As benchmark has MATLAB been used but one method has also been implemented in C/C++. Some of the methods works satisfactory when it comes to the image result but none of the methods works satisfactory when it comes to time consumption. To solve that a few speed up ideas are suggested in the end of the thesis. A method to correct the color of the sequences has also been suggested.

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Banerjee, Saptarshi. « Power Supply Rejection (PSR) Enhancement Techniques for Fully Integrated Low-Dropout (LDO) Regulators ». Thesis, Linköpings universitet, Elektroniska Kretsar och System, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-171553.

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In this present world, there is a huge requirement of portable devices for that the analysis of low-dropout or LDO regulators have been on high priority. So, for every respective device, there is a power budget that acts as the main constraint to design an LDO. The LDO design aims to suppress the noise and supply noise-free or low noise output. This thesis paper illustrates several designs of output capacitor-less LDO architecture to enhance Power Supply Rejection (PSR) and optimization of the ideas from different literature to achieve the low quiescent current, stability with fast transient response while the input voltage is low over a wide range of load current. Differ-ent types of transistor schematic designs under definite specifications of the LDOs, which are mostly integrated by major components like Error Amplifier (EA) and pass transistor, feedback resistors, and relatively small output capacitor have mostly considered for the designs. However, some buffer attenuation techniques which can improve the PSR have also been shown with a proper diagram. The design of LDOwith the components and how to design the pass device and their trade off’s have been has been discussed. Different techniques of PSR enhancement among which some of the techniques have been implemented have been illustrated with respective diagrams. A study of executed techniques under the specifications with comparative results has been shown with their trade-off with the other architecture. The contribution is an LDO that has been simulated in Cadence specter and designed in CMOS FinFET process node atVdd= 0.95 V with a load current of 50 mA -75 mA and an output voltage of 0.75 V with a small output capacitor of 200 pF, a PSR of−25 dB at 100 MHz has been achieved whereas the current consumption at the load is 245μA, while meeting the targeted stability analysis of gain margin and phase margin of 47 dB and 63◦respectively. A small voltage droop of 36. 6mV for rising edge and−15.99 mV for falling edge over a 100μA to 75 mA step-change in10 ns has been observed.
I dagens värld finns det stora behov av bärbara enheter och krav på analys avregulatorer (LDO). För varje typ av enhet finns det en energibudget som fungerarsom huvudsaklig begränsning för att utforma en LDO. LDO-konstruktion syftar tillatt leverera brusfri eller lågbrusig utspänning. Detta examensarbete visar på flerakonstruktioner av utgångskondensatorfria LDO-arkitekturer för att förbättra PowerSupply Rejection (PSR). Optimering av idéer från olika litteraturkällor görs för attuppnå låg viloström och stabilitet med snabb respons med låg ingångsspänning överett brett intervall av lastström. Olika typer av konstruktioner schemanivå för precisa LDO-specifikationer, mestadelsintegrerade med de viktigaste komponenter såsom felförstärkare (Error Amplifier,EA) och passtransistor, återkopplingsmotstånd och relativt små utgångskonden-satorer, har studerats. Buffertdämpningstekniker som kan förbättra PSR har ocksåinkluderats. Konstruktion av LDO:er på komponentnivå och man utformar pass-enheten och dess kompromisser diskuteras också. Implementering av några olikatekniker för PSR-förbättring illustreras med schema. En studie av utförda teknikerenligt specifikationerna med jämförande resultat ingår också. Resultat är en LDO som har simulerats i Cadence Spectre i en CMOS FinFETprocess med en matningsspänning på 0,95 V, en belastningsström på 50 mA - 75mA, en utspänning på 0,75 V och med en liten utgångskondensator på 200 pF. PSRpå−25 dB vid 100 MHz har uppnåtts medan strömförbrukningen vid belastningenär 245μA, samtidigt som kraven på marginal för förstärkning på 47 dB och fas 63°har uppnåtts. Ett litet spänningsfall på 36,6 mV för stigande signal och−15,99 mV för fallande signal under en förändring från 100 μA till 75 mA på 10 ns harobserverats.

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Ditri, Thomas Allan. « Upgrade and enhancement of the A.S. Department Financial Management Information System ; development of FMIS Property Management Module ». Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28624.

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Approved for public release; distribution is unlimited
The Administrative Sciences (AS) Department of the Naval Postgraduate School (NPS) maintains a large amount of plant and minor property to support its vast and varied operations. This property requires accurate record keeping to assure accountability of each item throughout its lifetime, from initial acquisition through disposal. The AS Department implemented a Financial Management Information System (FMIS), through the work of prior NPS students, at the commencement of FY 91. This thesis develops and integrates the Property Management Module into the FMIS to support the management and accountability of the AS Department property. The new expanded version is named FMIS 2.0. An outline covering software maintenance analysis, the Property Management system requirements analysis, and system design methodology is provided. The system was written using dBASE IV, version 1.1 and will transition to operational status from the current FMIS at the beginning of FY 92.

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Bethel, Matthew. « Geospatial Technology/Traditional Ecological Knowledge-Derived Information Tools for the Enhancement of Coastal Restoration Decision Support Processes ». ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1228.

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This research investigated the feasibility and benefits of integrating geospatial technology with traditional ecological knowledge (TEK) of an indigenous Louisiana coastal population in order to assess the impacts of current and historical ecosystem change to community viability. The primary goal was to provide resource managers with a comprehensive method of assessing localized ecological change in the Gulf Coast region that can benefit community sustainability. Using Remote Sensing (RS), Geographic Information Systems (GIS), and other geospatial technologies integrated with a coastal community's TEK to achieve this goal, the objectives were (1) to determine a method for producing vulnerability/sustainability mapping products for an ecosystem-dependent livelihood base of a coastal population that results from physical information derived from RS imagery and supported, refined, and prioritized with TEK, and (2) to demonstrate how such an approach can engage affected community residents who are interested in understanding better marsh health and ways that marsh health can be recognized, and the causes of declining marsh determined and addressed. TEK relevant to the project objectives collected included: changes in the flora and fauna over time; changes in environmental conditions observed over time such as land loss; a history of man-made structures and impacts to the area; as well as priority areas of particular community significance or concern. Scientific field data collection measured marsh vegetation health characteristics. These data were analyzed for correlation with satellite image data acquired concurrently with field data collection. Resulting regression equations were applied to the image data to produce estimated marsh health maps. Historical image datasets of the study area were acquired to understand evolution of land change to current conditions and project future vulnerability. Image processing procedures were developed and applied to produce maps that detail land change in the study area at time intervals from 1968 to 2009. This information was combined with the TEK and scientific datasets in a GIS to produce mapping products that provide new information to the coastal restoration decision making process. This information includes: 1) what marsh areas are most vulnerable; and 2) what areas are most significant to the sustainability of the community.

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Bowden, Todd H. « Design and Development of an Electronic Performance Enhancement Tool for Creating and Maintaining Information Management Web Sites ». Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/77315.

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This study explored the design and development of an electronic performance enhancement tool that can assist a person with limited programming skills to create a variety of simple customized information management websites. In particular, this study was modeled after needs within an Instruction Technology department in which individuals were able to create pre-functional web pages with various elements such as textboxes and dropdown menus but lacked the programming skills necessary to add functionality to these web forms. Skilled programmers could add functionality to these pre-functioning web forms or create customized information management websites from scratch. However, programmers are not always available when needed. At the time of this study, there was no readily available way for persons to create customized information management websites without the services of a programmer or without needing to learn programming skills themselves. This study sought to determine what functionalities, characteristics and capabilities could be included in an electronic performance enhancement tool to assist non-programmers to create simple customized information management websites and how a tool with such functionalities, characteristics and capabilities could be designed and developed. A prototype version of such tool (named the Form And DataBase Interaction Tool or "FADBIT") was designed and developed in this study. This tool asks users who have created simple pre-functional web forms to answer a series of questions related to those webforms. Given the user's responses to these questions, this tool is able to form a metalanguage representation of the user's intentions for the web form and can translate this representation into useful programming code to add the desired functionality. The tool was successfully designed and developed using a generalized modular framework, and a Create-Adapt-Generalize model, with each module addressing one or more patterns common to web programming. The prototype tool successfully allowed non-programmers to create functional information websites for two structured evaluation projects, and achieved some level of success and encountered some difficulties with an unstructured project. Proposed modifications and extensions to the tool to address the difficulties encountered are presented.
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Mallampati, Vivek. « Image Enhancement & ; Automatic Detection of Exudates in Diabetic Retinopathy ». Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-18109.

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Diabetic retinopathy (DR) is becoming a global health concern, which causes the loss of vision of most patients with the disease. Due to the vast prevalence of the disease, the automated detection of the DR is needed for quick diagnoses where the progress of the disease is monitored by detection of exudates changes and their classifications in the fundus retina images. Today in the automated system of the disease diagnoses, several image enhancement methods are used on original Fundus images. The primary goal of this thesis is to make a comparison of three of popular enhancement methods of the Mahalanobis Distance (MD), the Histogram Equalization (HE) and the Contrast Limited Adaptive Histogram Equalization (CLAHE). By quantifying the comparison in the aspect of the ability to detect and classify exudates, the best of the three enhancement methods is implemented to detect and classify soft and hard exudates. A graphical user interface is also adopted, with the help of MATLAB. The results showed that the MD enhancement method yielded better results in enhancement of the digital images compared to the HE and the CLAHE. The technique also enabled this study to successfully classify exudates into hard and soft exudates classification. Generally, the research concluded that the method that was suggested yielded the best results regarding the detection of the exudates; its classification and management can be suggested to the doctors and the ophthalmologists.

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Zhu, Jian. « Study of depth image based real time rendering and image enhancement ». Thesis, University of Macau, 2008. http://umaclib3.umac.mo/record=b1780620.

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Swarlis, Linda L. O'Connor Brian C. « Enhancement of spatial ability in girls in a single-sex environment through spatial experience and the impact on information seeking ». [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-9734.

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Trinkune, Anna Marija. « Enhancement of the Swedish Emergency Services : A study of the potential of human enhancement implementation within the Swedish police and fire and rescue service ». Thesis, Linköpings universitet, Institutionen för datavetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167198.

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Human enhancement (HE) is the field of research aiming to improve and overcome the biological limitations of the physical and mental performance of humans. The implications of HE might especially prove relevant within high-intensity environments, such as the working environment of police and fire and rescue services. The aim of this thesis is to identify the needs of personnel within these domains and to highlight potential HE solutions that could aid to improve responder performance in the setting of an active emergency. Interviews conducted with representatives for the Swedish police and fire and rescue service highlighted the need for support of mental performance in the form of destressing during highintensity situations as well as an improvement of creating situational awareness and making adequate decisions in a short amount of time. The results imply a potential of implementing HE solutions that aid emergency responders by keeping them alert and open for information gathering or minimizing the experienced level of stress while providing vital information for a proper response. The thesis alsoconcluded a generally positive attitude towards implementation of HE solutions.

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Bedoya, Ceballos Juan Carlos. « Optimization Methods for Distribution Systems : Market Design and Resiliency Enhancement ». Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/99489.

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The increasing penetration of proactive agents in distribution systems (DS) has opened new possibilities to make the grid more resilient and to increase participation of responsive loads (RL) and non-conventional generation resources. On the resiliency side, plug-in hybrid electric vehicles (PHEV), energy storage systems (ESS), microgrids (MG), and distributed energy resources (DER), can be leveraged to restore critical load in the system when the utility system is not available for extended periods of time. Critical load restoration is a key factor to achieve a resilient distribution system. On the other hand, existing DERs and responsive loads can be coordinated in a market environment to contribute to efficiency of electricity consumption and fair electricity tariffs, incentivizing proactive agents' participation in the distribution system. Resiliency and market applications for distribution systems are highly complex decision-making problems that can be addressed using modern optimization techniques. Complexities of these problems arise from non-linear relations, integer decision variables, scalability, and asynchronous information. On the resiliency side, existing models include optimization approaches that consider system's available information and neglect asynchrony of data arrival. As a consequence, these models can lead to underutilization of critical resources during system restoration. They can also become computationally intractable for large-scale systems. In the market design problem, existing approaches are based on centralized or computational distributed approaches that are not only limited by hardware requirements but also restrictive for active participation of the market agents. In this context, the work of this dissertation results in major contributions regarding new optimization algorithms for market design and resiliency improvement in distribution systems. In the DS market side, two novel contribution are presented: 1) A computational distributed coordination framework based on bilateral transactions where social welfare is maximized, and 2) A fully decentralized transactive framework where power suppliers, in a simultaneous auction environment, strategically bid using a Markowitz portfolio optimization approach. On the resiliency side, this research proposed a system restoration approach, taking into account uncertain devices and associated asynchronous information, by means of a two-module optimization models based on binary programming and three phase unbalanced optimal power flow. Furthermore, a Reinforcement Learning (RL) method along with a Monte Carlo tree search algorithm has been proposed to solve the scalability problem for resiliency enhancement.
Doctor of Philosophy
Distribution systems (DS) are evolving from traditional centralized and fossil fuel generation resources to networks with large scale deployment of responsive loads and distributed energy resources. Optimization-based decision-making methods to improve resiliency and coordinate DS participants are required. Prohibitive costs due to extended power outages require efficient mechanisms to avoid interruption of service to critical load during catastrophic power outages. Coordination mechanisms for various generation resources and proactive loads are in great need. Existing optimization-based approaches either neglect the asynchronous nature of the information arrival or are computationally intractable for large scale system. The work of this dissertation results in major contributions regarding new optimization methods for market design, coordination of DS participants, and improvement of DS resiliency. Four contributions toward the application of optimization approaches for DS are made: 1) A distributed optimization algorithm based on decomposition and best approximation techniques to maximize social welfare in a market environment, 2) A simultaneous auction mechanism and portfolio optimization method in a fully decentralized market framework, 3) Binary programming and nonlinear unbalanced power flow, considering asynchronous information, to enhance resiliency in a DS, and 4) A reinforcement learning method together with an efficient search algorithm to support large scale resiliency improvement models incorporating asynchronous information.

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Dolan, Philip R. « Ultra-small open access microcavities for enhancement of the light-matter interaction ». Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:d949537f-cef4-4ee9-aa98-471331857a15.

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The design, construction and characterisation of a novel, arrayed, open-access optical microcavity is described. Included in this thesis are the precise fabrication details, making use of the focused ion beam. A technique for analysing and optimising the microcavities constructed, making use of an atomic force microscope is also included. Results from the optical characterisation of the fabricated microcavities are presented, including quality factors of around 104, and fitnesses of around 400. The optical analysis then progressed onto coupling colloidal semiconductor nanocrystals to the microcavity modes. This yielded room temperature Purcell enhancements, single particle sensing, and also allowed for the characterisation of a second iteration of cavities. This improved set was shown to achieve fitnesses in excess of 1800 and quality factors with a lower limit of 15000. The optical identification of single NV centres in nanodiamond is discussed, along with the development of an optical apparatus to couple them to microcavities at cryogenic temperatures. Finally several results from finite difference time domain simulations will be presented, showing ultimate mode volumes of less than 0.5 cubic wavelengths are possible for this approach.

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Tjäder, Hampus. « End-to-end Security Enhancement of an IoT Platform Using Object Security ». Thesis, Linköpings universitet, Informationskodning, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138838.

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The Internet of Things (IoT) is seen as one of the next Internet revolutions. In a near future the majority of all connected devices to the Internet will be IoT devices. These devices will connect previously offline constrained systems, thus it is essential to ensure end-to-end security for such devices. Object Security is a concept where the actual packet or sensitive parts of the packet are encrypted instead of the radio channel. A compromised node in the network will with this mechanism still have the data encrypted ensuring full end-to-end security. This paper proposes an architecture for using the object security format COSE in a typical constrained short-range radio based IoT platform. The IoT platform utilizes Bluetooth Low Energy and the Constrained Application Protocol for data transmission via a capillary gateway. A proof-of-concept implementation based on the architecture validates that the security solution is implementable. An overhead comparison between current channel security guidelines and the proposed object security solution results in a similar size for each data packet. The thesis concludes that object security should be seen as an alternative for ensuring end-to-end security for the Internet of Things.

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