111 |
Feature selection and artifact removal in sleep stage classificationHapuarachchi, Pasan January 2006 (has links)
The use of Electroencephalograms (EEG) are essential to the analysis of sleep disorders in patients. With the use of electroencephalograms, electro-oculograms (EOG), and electromyograms (EMG), doctors and EEG technician can make conclusions about the sleep patterns of patients. In particular, the classification of the sleep data into various stages, such as NREM I-IV, REM, Awake, is extremely important. The EEG signal itself is highly sensitive to physiological and non-physiological artifacts. Trained human experts can accommodate for these artifacts while they are analyzing the EEG signal. <br /><br /> However, if some of these artifacts are removed prior to analysis, their job will be become easier. Furthermore, one of the biggest motivations, of our team's research is the construction of a portable device that can analyze the sleep data as they are being collected. For this task, the sleep data must be analyzed completely automatically in order to make the classifications. <br /><br /> The research presented in this thesis concerns itself with the <em>denoising</em> and the <em>feature selection</em> aspects of the teams' goals. Since humans are able to process artifacts and ignore them prior to classification, an automated system should have the same capabilities or close to them. As such, the denoising step is performed to condition the data prior to any other stages of the sleep stage neoclassicisms. As mentioned before, the denoising step, by itself, is useful to human EEG technicians as well. <br /><br /> The denoising step in this research mainly looks at EOG artifacts and artifacts isolated to a single EEG channel, such as electrode pop artifacts. The first two algorithms uses Wavelets exclusively (BWDA and WDA), while the third algorithm is a mixture of Wavelets and In- dependent Component Analysis (IDA). With the BWDA algorithm, determining <em>consistent</em> thresholds proved to be a difficult task. With the WDA algorithm, the performance was better, since the selection of the thresholds was more straight-forward and since there was more control over defining the duration of the artifacts. The IDA algorithm performed inferior to the WDA algorithm. This could have been due to the small number of measurement channels or the automated sub-classifier used to select the <em>denoised EEG signal</em> from the set of ICA <em>demixed</em> signals. <br /><br /> The feature selection stage is extremely important as it selects the most pertinent features to make a particular classification. Without such a step, the classifier will have to process useless data, which might result in a poorer classification. Furthermore, unnecessary features will take up valuable computer cycles as well. In a portable device, due to battery consumption, wasting computer cycles is not an option. The research presented in this thesis shows the importance of a systematic feature selection step in EEG classification. The feature selection step produced excellent results with a maximum use of just 5 features. During automated classification, this is extremely important as the automated classifier will only have to calculate 5 features for each given epoch.
|
112 |
The Ambitious City: Stimulating Change through the Urban ArtifactFearman, Carolyn January 2011 (has links)
In the late twentieth century, global economic forces changed the face of many North American cities. Cities which were built upon industry, that had provided both job certainty and economic vitality, faced questions of survival in response to shrinking population and urban blight. Unprepared for these drastic changes and unable to address them survival gave way to resignation.
Buffalo, New York is an example of a once successful and vital city that continues to experience de-population due to the collapse of its industries. The collapse not only created economic repercussions but also effected the city’s built environment. Many of the Buffalo’s urban monuments, testaments to the ambition of the city, now sit empty; as do the working class neighbourhoods that surround them.
The Thesis examines the role which architecture can play in understanding, strategizing and re-envisioning the life of deteriorating cities. Focusing on the City of Buffalo, the design centers on the New York Central Terminal. It proposes a radical repurposing of the Terminal to create a new urban hub which will spur the re-building of the city’s urban fabric.
The design outlines a staged 25 year strategy for the de-construction of sparse areas and the strengthening of critical urban networks, thus creating a strong framework upon which a new physical fabric for the city can build and develop overtime. The Terminal, once a significant rail hub is re-envisioned as a revitalized hub for the new city. A key connective point within this urban framework, it encapsulates a variety of program moved from the surrounding neighbourhood to the site. The Terminal will act as an architectural catalyst for change, working within the larger urban strategy to spur a natural re-growth and densification of the city.
The thesis presents the radical re-thinking of the architect’s role in the twenty-first century. As current economies and industries face change the urban climate is adapting from one of constant growth to one of strategic re-use. Skeletons of once successful cities lay across the North American landscape. Their urban artifacts: the grain mill, steel manufacturing plant and rail yards, which once supported whole cities as both providers of employment and definers of cultural identity, now stand as empty reminders of a prosperous past. The Thesis shows how these buildings , like the New York Central Terminal can be given a renewed cultural significance and powerful roles within the revived urban life of their cities.
|
113 |
Projektų dokumentavimo sistema „MagicDraw“ CASE įrankio pagrindu / Project documentation system based on MagicDaw UML CASE toolSavulis, Raimondas 01 September 2011 (has links)
Programinės įrangos kūrimo projektų dokumentacijos kūrimas dažnai vykdomas neefektyviai – dokumentai kuriami lėtai, esama dokumentavimo metodika būna perteklinė, nėra vieningos dokumentacijos kūrimo strategijos. Vienas iš būdų paspartinti dokumentų ruošimo procesą – panaudoti šiame darbe suformuluotus nurodymus bei principus. Taikant sukurtus dokumentų šablonus, dokumentaciją galima generuoti tiesiai iš projektavimo įrankio. Šiuose šablonuose realizuotas papildomas funkcionalumas – projekto kūrimo ir testavimo darbų apimčių skaičiavimas bei elementų ryšių vientisumo nustatymas, o tai svarbu vertinant projekto kokybę ir planuojant kūrimo darbus. Sukūrus projektą, dokumentacija automatiškai sugeneruojama panaudojant projektavimo įrankio, pavyzdžiui, MagicDraw UML, teikiamas dokumentų generavimo priemones, todėl nereikia atskirai kurti dokumentacijos teksto redagavimo priemonėmis. Sukurtąjį dokumento šabloną galima pakartotinai panaudoti kituose projektuose. / Creation of documentation usually is inefficient - documents are being created slowly, the methodology of documentation is usually redundant, there is no common strategy for this. The paper proposes a way to boost the process of creating documentation by using documentation templates that give an opportunity to generate documentation directly from a CASE tool. The created template implements additional functionality - the estimation of a size of programming and testing tasks of a project and tracing the dependencies between project's elements. The implemented template of a document may be applied in more than one project.
|
114 |
Efficient data acquisition, transmission and post-processing for quality spiral Magnetic Resonance ImagingJutras, Jean-David Unknown Date
No description available.
|
115 |
The Ambitious City: Stimulating Change through the Urban ArtifactFearman, Carolyn January 2011 (has links)
In the late twentieth century, global economic forces changed the face of many North American cities. Cities which were built upon industry, that had provided both job certainty and economic vitality, faced questions of survival in response to shrinking population and urban blight. Unprepared for these drastic changes and unable to address them survival gave way to resignation.
Buffalo, New York is an example of a once successful and vital city that continues to experience de-population due to the collapse of its industries. The collapse not only created economic repercussions but also effected the city’s built environment. Many of the Buffalo’s urban monuments, testaments to the ambition of the city, now sit empty; as do the working class neighbourhoods that surround them.
The Thesis examines the role which architecture can play in understanding, strategizing and re-envisioning the life of deteriorating cities. Focusing on the City of Buffalo, the design centers on the New York Central Terminal. It proposes a radical repurposing of the Terminal to create a new urban hub which will spur the re-building of the city’s urban fabric.
The design outlines a staged 25 year strategy for the de-construction of sparse areas and the strengthening of critical urban networks, thus creating a strong framework upon which a new physical fabric for the city can build and develop overtime. The Terminal, once a significant rail hub is re-envisioned as a revitalized hub for the new city. A key connective point within this urban framework, it encapsulates a variety of program moved from the surrounding neighbourhood to the site. The Terminal will act as an architectural catalyst for change, working within the larger urban strategy to spur a natural re-growth and densification of the city.
The thesis presents the radical re-thinking of the architect’s role in the twenty-first century. As current economies and industries face change the urban climate is adapting from one of constant growth to one of strategic re-use. Skeletons of once successful cities lay across the North American landscape. Their urban artifacts: the grain mill, steel manufacturing plant and rail yards, which once supported whole cities as both providers of employment and definers of cultural identity, now stand as empty reminders of a prosperous past. The Thesis shows how these buildings , like the New York Central Terminal can be given a renewed cultural significance and powerful roles within the revived urban life of their cities.
|
116 |
博物館文物展示網站的服務品質:以國立故宮院為例 / Service quality of museum website displaying artifact: the case of National Palace Museum吳宗勳 Unknown Date (has links)
隨著資訊及通訊(資通訊)技術的進步,越來越多的博物館服務提供者開始思考如何應用資通訊的技術。位於台灣的國立故宮博物院(故宮)也不例外,已經建置了自己的網站。對於一個博物館網站,可以並可能提供的功能是相當多。而故宮網站期望能提供的功能之一,即是展示文物。傳統的設計方式,網站通常被建置以圖文的方式來展示文物。在這份研究中,我們呈現了一個故宮提出的影音服務提案及原型,the iPalace Video Channel(the iPalace)。這個服務主要藉由影音來展示中華文物,並有著隱喻式設計介面。現在這個由資通技術訊所促成的博物館服務提案就開始被建置,而故宮的管理人員希望知道是否值得發展並建置這個新服務。除此之外,當決定正式佈署這個服務時,故宮的管理人員也希望從已建置的服務原型了解這個服務的優缺點。因此,這份研究特別針對用於展示文物的博物館網站設計了問卷來測量其服務品質、顧客滿意度和行為意向。我們並藉由網路上發放此問卷來調查實驗組(the iPalace)以及對照組(圖文式網站)的使用者。藉由分析問卷測量的結果,我們得到了四個重要的服務品質因素:功能性、內容及使用性、系統穩定性和介面呈現。除此之外,藉由T檢定來分析問卷的測量結果,觀察the iPalace及圖文式網站在這些服務品質因素上,所測到的服務品質、顧客滿意度和行為意向是否存在著統計上顯著的差異。而結果顯示,因為較佳的功能性及介面呈現服務品質,the iPalace的使用者有較高的滿意度,他們也較願意推薦並再次使用這個網站。然而the iPalace於系統穩定性服務品質上的表現較差,原因為較差的反應時間。 / Following the advancement of information and communication technologies (ICT), more and more museum service providers begin to take the ICT applications into considerations. The National Palace Museum (the NPM) in Taiwan is no exception and has built its own website. For a museum website, there are many possible functions which can be provided. One of the NPM website’s desired functions is to display artifacts. With the traditional design, the website is built for displaying artifacts mainly through texts and pictures. In this study, we present the iPalace Video Channel (the iPalace), a new video-based service proposed by the NPM, that displays Chinese artifacts mainly via videos and has a metaphorical interface design. When a new ICT-enabling museum service proposal is initialized, the manager wonders whether it is worthwhile to develop and deploy the new service. And, as soon as we had decided to develop and deploy the service and have obtained a prototype system, the manager would further wants to know the advantages and disadvantages of the new service before full launching it. Thus, this study derives the instrument for measuring the service quality, customer satisfaction and behavioral intention regarding the museum website displaying artifacts. Through an online survey that applies the derived instrument to measure the iPalace and its text-based counterpart, we identify the following four important service quality factors: FULFILLMENT, CONTENT & USABILITY, SYSTEM RELIABLITY and INTERFACE. From the t-test on the survey data, we also assess whether there are statistically differences on each service quality factor between the iPalace and its text-based counterpart. And the result shows that, owing to the better performance on the service quality factors of FULFILLMENT and INTERFACE, the iPalace users are more satisfied with the website than the text-based website users. And they are more willing to recommend and reuse the website than the text-based website users. However, the iPalace has a lower performance on the service quality factor of SYSTEM RELIABILITY due to the slower response time.
|
117 |
Modélisation de la détection de défauts et perception de la qualité d'images radiologiques / Modelling the detection of artifacts and the perception of the quality of radiological imagesAcharian, Georges 09 October 2015 (has links)
Depuis la fin du 20ème siècle, l'imagerie médicale s'est fortement développée et représente aujourd'hui un moyen incontournable pour le diagnostic médical. Dans le domaine de la radiologie par rayons X, de nouveaux détecteurs numériques remplacent progressivement les anciennes techniques à film et permettent d'obtenir des images de meilleure qualité. Cette thèse, préparée en collaboration entre l'entreprise Trixell, constructeur de détecteurs plats numériques pour la radiographie, et le laboratoire Gipsa-Lab, s'inscrit dans le cadre général du contrôle qualité de ces détecteurs par analyse d'images. Les applications biomédicales mettant en jeu ces appareils, sont généralement particulièrement sensibles, et le principe de « zéro défaut » est de mise quant à la qualité des produits. Malgré les différents traitements, certains défauts peuvent être présents dans les images. Cette thèse est axée sur le développement de modèles de mesure de la visibilité des défauts, en cohérence avec l'observation d'un humain. Deux approches complémentaires sont développées : la première approche basée sur des expériences psychophysiques et la seconde approche de modélisation basée sur la théorie de décision. Par rapport aux modèles de visibilité existants, notre modèle prend en compte la perception humaine et notamment les saccades et fixations oculaires dans l'analyse des images : le test de visibilité est ainsi le produit de tests de visibilité locaux, calculés aux points saillants de l'image supposés indépendants. Les résultats montrent l'intérêt de notre approche, notamment pour des détecteurs statiques. En se fondant sur les résultats et une dernière expériences d'oculométrie, cette thèse suggère en perspective la prise en compte d'autres caractéristiques comme le nombre de fixations oculaires, et leur durée. / Since the beginning of the 20th century, medical imaging has significantly been improved and represents now an essential mean for medical diagnosis. In the field of radiology, new digital detectors are gradually replacing the old film techniques allowing a better image. This thesis, prepared in collaboration between the company Trixell, manufacturer of X-ray detectors, and the laboratory Gipsa-Lab, is part of the framework of quality control of these detectors by image analysis. Biomedical applications involved by these devices are particularly sensitive, and the principle of “zero artifact” is required to ensure the quality of the product. Despite the various processings, some artifacts may be present in the images.This thesis focuses on the development of models that quantify the visibility of artifacts in concordance to human observation. Two complementary approaches are developed : the first one is based on psychophysical experiments and the second one is a modeling approach based on decision theory. In comparison to existent models, our model takes into account perception characteristics including saccades and eye fixation in image analysis : the visibility test is thus the product of local visibility tests calculated on the salient points of the image and assumed to be independent. The results show the interest of our approach, especially for static detectors. Based on the results and a final eye-tracking experiment, this thesis suggests perspectives taking into account other characteristics such as the number of eye fixations and their duration.
|
118 |
Une méthode pour l'évaluation de la qualité des images 3D stéréoscopiques. / The objective and subjective quality of 3D imagesVlad, Raluca Ioana 02 December 2013 (has links)
Dans le contexte d'un intérêt grandissant pour les systèmes stéréoscopiques, mais sans méthodes reproductible pour estimer leur qualité, notre travail propose une contribution à la meilleure compréhension des mécanismes de perception et de jugement humains relatifs au concept multi-dimensionnel de qualité d'image stéréoscopique. Dans cette optique, notre démarche s'est basée sur un certain nombre d'outils : nous avons proposé un cadre adapté afin de structurer le processus d'analyse de la qualité des images stéréoscopiques, nous avons implémenté dans notre laboratoire un système expérimental afin de conduire plusieurs tests, nous avons crée trois bases de données d'images stéréoscopiques contenant des configurations précises et enfin nous avons conduit plusieurs expériences basées sur ces collections d'images. La grande quantité d'information obtenue par l'intermédiaire de ces expérimentations a été utilisée afin de construire un premier modèle mathématique permettant d'expliquer la perception globale de la qualité de la stéréoscopie en fonction des paramètres physiques des images étudiée. / In a context of ever-growing interest in stereoscopic systems, but where no standardized algorithmic methods of stereoscopic quality assessment exist, our work stands as a step forward in the understanding of the human perception and judgment mechanisms related to the multidimensional concept of stereoscopic image quality. We used a series of tools in order to perform in-depth investigations in this direction: we proposed an adapted framework to structure the process of stereoscopic quality assessment, we implemented a stereoscopic system in our laboratory for performing various tests, we created three stereoscopic datasets with precise structures, and we performed several experimental studies using these datasets. The numerous experimental data obtained were used in order to propose a first mathematical framework for explaining the overall percept of stereoscopic quality in function of the physical parameters of the stereoscopic images under study.
|
119 |
Desenvolvimento de uma ferramenta para automatizar redução de artefato metálico em imagens de tomografias computadorizadasPaulino, José Alberto Souza 08 May 2017 (has links)
Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-10-23T13:03:47Z
No. of bitstreams: 1
PDF - José Alberto Souza Paulino.pdf: 32306126 bytes, checksum: d8a3a4c1c537e36b743590e029308f8c (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2017-10-26T16:55:17Z (GMT) No. of bitstreams: 1
PDF - José Alberto Souza Paulino.pdf: 32306126 bytes, checksum: d8a3a4c1c537e36b743590e029308f8c (MD5) / Made available in DSpace on 2017-10-26T16:55:17Z (GMT). No. of bitstreams: 1
PDF - José Alberto Souza Paulino.pdf: 32306126 bytes, checksum: d8a3a4c1c537e36b743590e029308f8c (MD5)
Previous issue date: 2017-05-08 / This research proposes to evaluate and implement a solution for metal artifact reduc- tion in computed tomography, this one aiming to meet a demand from the prototyping laboratory of the Núcleo de Tecnologias Estratégicas em Saúde (Nutes) da Univer- sidade Estadual da Paraíba, where impressions of biomodels are made for surgical planning. The CT affected by metal artifacts need to be corrected prior to the printing process, this manual intervention implies excessive delay for delivery of the biomodels. The development of the proposed solution is based on the sinogram correction method which according to Mouton et al (2013) and Gjesteby (2016) is the most utilized method for reducing metal artifacts and makes uses of linear interpolation to correction the cor- rupted data. In order to validate the preference for linear interpolation in the state of the art, others interpolative techniques were implemented and evaluated; Fist through simulations and then by a form for qualitative evaluation, upon which statistical tests were applied. The results obtained confirm the use of interpolation as the best option for the reconstruction of data corrupted by metallic artifacts. / Esta pesquisa se propõe a avaliar e implementar uma solução para redução de artefatos metálicos em tomografias computadorizadas, solução esta que visa atender uma demanda do laboratório de prototipagem do Núcleo de Tecnologias Estratégicas em Saúde (Nutes) da Universidade Estadual da Paraíba, onde são realizadas impressões de biomodelos para planejamentos cirúrgicos. As tomografias afetadas por artefatos metálicos necessitam de correção antes do processo de impressão, esta intervenção realizada de forma manual implica em demora excessiva para entrega dos biomodelos. O desenvolvimento da solução proposta baseia-se no método de correção de sinograma que, de acordo com Mouton et al (2013) e Gjesteby (2016), é o método mais difundido para redução de artefatos metálicos e faz uso da técnica de interpolação linear para correção dos dados corrompidos. Objetivando validar a preferência pelo uso da interpolação linear no estado da arte, foram implementadas outras técnicas interpolativas as quais foram submetidas a avaliação; Primeiro por meio de simulações e depois via fomulário para avaliação qualitativa, na qual foram aplicados testes estatísticos. Os resultados obtidos ratificam o uso da interpolação linear como melhor opção para reconstrução de dados corrompidos pelos artefatos metálicos.
|
120 |
Avaliação do comportamento de seladores endodônticos e a influência destes materiais sobre o diagnóstico de fraturas radiculares por meio de tomografia computadorizada por feixe cônico / Endodontic fillings behavior evaluation and their influence in root fracture diagnosis by means of cone beam computed tomographyFernanda Cristina Sales Salineiro 20 April 2018 (has links)
A tomografia computadorizada por feixe cônico (TCFC) tem apresentado melhores resultados em relação a radiografia convencional no diagnóstico da região de cabeça e pescoço. Porém a presença de artefatos nas imagens tomográficas podem interferir na acurácia do diagnóstico. O presente estudo teve como objetivo avaliar a influência de diferentes tipos de preenchimentos endodônticos na formação de artefato nas imagens de TCFC e avaliar a influência destes no diagnóstico de fratura radicular. Foram utilizados 200 dentes (100 incisivos centrais superiores e 100 prémolares inferiores) subdivididos em 10 grupos diferenciando o tipo de preenchimento endodôntico. Os dentes foram escaneados utilizando um tomógrafo computadorizado por feixe cônico. Inicialmente foi realizada uma medição nas imagens tomográficas com a ferramenta de informação sobre a área (ROI) e avaliação subjetiva das imagens para realizar uma comparação entre os cimentos endodônticos. Após essa fase, 100 dentes foram fraturados para realizar a última análise que foi o diagnóstico de fratura radicular. Para análise dos dados da ferramenta ROI foram utilizados a análise de Kruskal-Wallis e o teste post hoc Dunn, para comparar os dados subjetivos foi utilizado o teste de Kruskal-Wallis e para os dados de diagnóstico de fratura radicular foi calculado a Curva de característica de operação do receptor (ROC) e o teste ANOVA e o teste post hoc Tukey para os valores de área sob a curva (ASC). Resultados: O terço médio foi a região que gerou mais variações na escala de cinza para ambos os dentes. O Pulp Canal Sealer e o Sealer 26 foram os cimentos que mais alteraram as imagens segundo a análise subjetiva. Os valores de ASC variaram de 0.530 a 0.745. Conclusão: Todos os materiais produziram artefato nas imagens por TCFC, dificultando o diagnóstico de fratura radicular. / Cone beam computed tomography (CBCT) has shown better results than conventional radiographs on head and neck diagnosis. However, the presence of artifact in the CBCT images could interfere on diagnosis accuracy. The aim of this study was to evaluate the influence of different types of endodontic fillings and analyze the influence of these materials in root fracture diagnosis. Two hundred teeth (100 superior incisors and 100 inferior premolars) were divided in 10 groups categorized by each typo of endodontic filling. All teeth were scanned by using CBCT device. Initially, a measurement was performed on CBCT images using the Region of Interest (ROI) tool and a subjective analysis of the images was carried on to compare the different endodontic fillings. After this phase, 100 teeth were fractured to perform the last analysis: root fracture diagnosis. Kruskall-Wallis analyses for ROI tool data was performed with the aid of post hoc Dunn test, Kruskal-Wallis test was selected for the subjective data assessment and receiver operating characteristic (ROC) curves were used for root fracture diagnosis analyses and the variance analysis with the post hoc Tukey test for AUC values. The middle third was the region that developed more grayscale variations for both teeth. At the subjective analysis, Pulp Canal Sealer and Sealer 26 were selected as the ones that produced more images alterations. AUC ROC values ranged from 0.530 to 0.745. Conclusion: All materials produced artifact in CBCT images, making the root fracture diagnosis more difficult.
|
Page generated in 0.0574 seconds