• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 113
  • 34
  • 22
  • 19
  • 9
  • 6
  • 6
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 246
  • 62
  • 33
  • 33
  • 25
  • 23
  • 23
  • 22
  • 21
  • 18
  • 17
  • 17
  • 17
  • 17
  • 16
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Design of Multifunctional and Sustainable Backpacks : Combining Skiing, Snowboarding, and Urban Usage

Jonsson, Marcus January 2018 (has links)
Today, backpacks and duffel bags are often designed with a focus on a specific area of use, which makes it difficult to use them on other occasions. A clear example where the differences are noticeable is between functional mountaineer bags and urban bags. It is not uncommon for people staying in these environments to have far beyond two bags in their possession. Overconsumption is harmful to the environment, especially when it is from an industry that is pursued with poor working conditions and dangerous emissions in nature. Therefore, multifunctionality and sustainable design have been of high priority when the products in this project were developed. In this thesis, two models of bags have been developed through a human-centered design process. A large number of user interviews and expert interviews, as well as a focus group, laid the foundation for the requirements and needs of the bags. Spektrum’s company values, as well as the identity of their current products, were interpreted to create brand recognition in the new products. Idea generation was performed through various creative sessions, prototyping, and through a workshop. Evaluation and concept selection was performed by representatives from the target group in the form of personas, as well as by Spektrum. Finally, detailed technical drawings of the concepts were created in Adobe Illustrator. The first model is a backpack designed to work just as well on the mountain as in the city. The other model is a duffel bag that can be carried both on the back and in the hand. It is also designed to perform well in both mountain and urban environments. Both bags are made of polyester from recycled PET bottles and the material is controlled and approved by the highly rated environmental certification bluesign®. The metal parts of the bags are made of recycled aluminum. Both models are adjustable to fit all users within the 5th to 95th percentile. The thesis resulted in the ordering of two alpha prototypes of each model, factory-made by my technical drawings. According to Spektrum, the designs have created great interest among retailers and company shareholders. Both models will, therefore, be put into production and released to the market within two years.
142

Estudo do efeito eletrostático na filtração de partículas de cimento em filtros de mangas

Oliveira, Flávia Matias 30 April 2015 (has links)
Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-09-30T17:56:23Z No. of bitstreams: 1 DissFMO.pdf: 2016401 bytes, checksum: 6866947ec8d256db2aefd27468b572ce (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-04T17:30:18Z (GMT) No. of bitstreams: 1 DissFMO.pdf: 2016401 bytes, checksum: 6866947ec8d256db2aefd27468b572ce (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-04T17:30:30Z (GMT) No. of bitstreams: 1 DissFMO.pdf: 2016401 bytes, checksum: 6866947ec8d256db2aefd27468b572ce (MD5) / Made available in DSpace on 2016-10-04T17:30:37Z (GMT). No. of bitstreams: 1 DissFMO.pdf: 2016401 bytes, checksum: 6866947ec8d256db2aefd27468b572ce (MD5) Previous issue date: 2015-04-30 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Nowadays the control of industrial pollution is essential. Through filtering, you can remove the suspended solids in gases. It has been need for more efficient methods for gas filtration in order to reduce waste generation and decrease energy consumption. In this study was proposed to investigate the behavior of the particulate matter, cement and the influence of particle size in formation of gas dust cake, with and without eletrostatic charged. The filter in order to determine aspects were analyzed and compare their characteristics after filtration, defining which one operationally more suitable for this process. In this investigation the study aims optimize the filtration operation. In order to obtain a greater retention of particulates. In this sense, fabric filter were analyzed, glass and polypropylene filter, while gas filtration. Cement was used as particulate material with grain sizes 8, 14 and 20μm, the corona chargering was added in the filtration of gas during the formation of dust cake. The tests were conduction in an attempt to understand this effect the electrostatic charge, improve and increase the service life of the filter media. Was necessary to adapt it to the equipment one system gas filtration, localized in Department of Chemical Engineering (DEQ) of Federal University of São Carlos (UFSCar), for receive the corona charged. The experiment was conducted from voltage of 0 to -2 kV test with a filtration rate of 10 cm/s, and the mass flow of 9 mg/s. With the tests done, it possible show that, with the application the corona chargering the dust cake changes. It can be that the particle size directly affects the filtration efficiency and the load, can increase the efficiency the collect to particulate and decrease pressure drop during filtration of gases. / Atualmente o controle da poluição industrial é essencial. Através da filtração, é possível remover os sólidos suspensos nos gases. Tem-se então a necessidade de métodos eficientes para filtração de gases a fim de reduzir a geração de resíduos e diminuir o consumo de energia. O presente estudo objetivou investigar o comportamento do material particulado, cimento e a influência do seu tamanho de partícula na formação da torta de filtração de gases, com e sem carregamento eletrostático. Foram analisados os aspectos do filtro com intuito de determinar e comparar suas características após as filtrações, definindo qual delas será mais adequada operacionalmente para este processo. Além destas investigações o estudo busca otimizar a operação de filtração. Para que se possa obter uma maior retenção de particulados. Neste sentido, foram analisados filtros de tecidos, de fibra de vidro e polipropileno, durante a filtração de gases. Utilizou-se o cimento como material particulado, com granulometrias de 8, 14 e 20μm, o carregamento corona foi adicionado na filtração durante a formação da torta de filtração. Os testes foram realizados na tentativa de compreender esses efeitos causados a partir de cargas eletrostáticas, objetivando melhorar e aumentar o tempo de vida útil dos meios filtrantes. Para isso adaptou-se um sistema de filtração de gases, existente no Departamento de Engenharia Química (DEQ) da Universidade Federal de São Carlos (UFSCar), para receber um carregador corona. Posteriormente determinou-se o ponto ótimo de operação a uma vazão mássica de 9 mg/s e velocidade de filtração de 10 cm/s, variando-se a tensão da unidade entre 0, e -2,0 kV. Através dos ensaios realizados foi possível observar que, com a aplicação da corrente corona, ocorreu uma alteração na formação da torta de filtração. Pode-se dizer que o tamanho da partícula afeta diretamente a eficiência da filtração e que a carga, pode aumentar a eficiência de coleta das partículas e diminuir a perda de carga durante a filtração de gases.
143

Desenvolvimento de modelo gen?rico de balanced scorecard para institui??es privadas de ensino fundamental e m?dio

Costa, Izaac Shallon Gomes 13 May 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-03T20:52:32Z No. of bitstreams: 1 IzaacShallonGomesCosta_DISSERT.pdf: 2146540 bytes, checksum: 3aa228f209db597dfdf9c5698954fd17 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-06T21:57:48Z (GMT) No. of bitstreams: 1 IzaacShallonGomesCosta_DISSERT.pdf: 2146540 bytes, checksum: 3aa228f209db597dfdf9c5698954fd17 (MD5) / Made available in DSpace on 2017-04-06T21:57:48Z (GMT). No. of bitstreams: 1 IzaacShallonGomesCosta_DISSERT.pdf: 2146540 bytes, checksum: 3aa228f209db597dfdf9c5698954fd17 (MD5) Previous issue date: 2016-05-13 / O Balanced Scorecard (BSC) ? uma metodologia para gest?o estrat?gica j? consolidada mundialmente desde os anos 1990. Este sistema tem sido aplicado em empresas de diversos setores do mercado, em institui??es privadas e p?blicas, devido a sua flexibilidade. O setor educacional est? cada vez mais competitivo e h? crescente busca por qualidade e consequente necessidade de melhoria da gest?o das institui??es de ensino. Diversos estudos mostram o sucesso do uso do BSC em educa??o em diferentes pa?ses, mas poucos no ?mbito da educa??o b?sica. Dentro deste escopo, o objetivo deste trabalho ? o desenvolvimento de um modelo de BSC na ?rea educacional, aplic?vel a escolas privadas que trabalham tanto com ensino fundamental como com n?vel m?dio. O modelo preliminar de objetivos e indicadores para o BSC foi desenvolvido com base na revis?o da literatura. A partir deste modelo inicial seguiu-se a elabora??o de question?rios, que foram aplicados em entrevistas com gestores escolares, para realiza??o de um estudo da viabilidade de uma futura implanta??o do BSC em institui??es de ensino, bem como possibilitando a coleta de informa??es para a valida??o do conjunto de objetivos estrat?gicos para as quatro perspectivas do BSC, chegando-se aos mais importantes, considerando o contexto da regi?o pesquisada. Foi utilizada uma t?cnica chamada de ?bag of stars? na aplica??o dos question?rios para filtrar os objetivos e indicadores. Os resultados foram a descri??o do panorama geral sobre a gest?o estrat?gica nas escolas pesquisadas, o modelo de BSC para institui??es privadas de ensino fundamental e m?dio e um mapa estrat?gico desenvolvido a partir dos objetivos presentes no modelo. O modelo proposto oferece uma base para a implementa??o do BSC em escolas, especialmente com o perfil compreendido na pesquisa. O trabalho ? uma refer?ncia para a amplia??o do conhecimento e explora??o de novos estudos sobre gest?o escolar. / The Balanced Scorecard (BSC) is a methodology for strategic management worldwide consolidated since the 1990s. This system has been applied in various market sectors, in private and public institutions, because of its flexibility. The educational sector is increasingly competitive and there is growing demand for quality and the consequent need to improve the management of educational institutions. Several studies show the success of the BSC use on education in different countries, but few in the context of basic education. Within this scope, the objective of this work is the development of a BSC model in education field, applicable to private schools that work with both elementary and middle level. The preliminary model of objectives and indicators for BSC was developed based on the literature review. From this initial model was followed by the development of questionnaires, that they were applied in interviews with school managers, to conduct a feasibility study of a future implementation of the BSC in in educational institutions, as well as enabling the collection of information for validating the set of strategic objectives for the four perspectives of the BSC, obtaining the most importante, considering the context of the area surveyed. A technique called "bag of stars" was used in the application of questionnaires to filter the objectives and indicators. The results were the description of the general overview of strategic management in the surveyed schools, the model of BSC for elementary and high school private institutions and a strategic map developed from the objectives present in the model. The proposed model provides a basis for implementing the BSC in schools, especially with the profile comprised in the search. The work is a reference to the expansion of knowledge and exploration of new studies on school management.
144

Management of Wastes in the Chemistry Laboratories / Gestión de Residuos en los Laboratorios de Química

Loayza Pérez, Jorge Eduardo 25 September 2017 (has links)
Las instituciones educativas y las empresas de servicios que cuenten con laboratorios de química o afines, para realizar experiencias de laboratorio o análisis químicos como parte de los servicios prestados a terceros, requieren al igual que las empresas productivas, de una gestión y un adecuado manejo de sus residuos químicos. Para ello, deben elaborar y aplicar un Plan de Manejo de Residuos Químicos de Laboratorio y dependiendo del tamaño de la institución (u organización) deberán contar con un sistema de información conocido como Bolsa de Residuos Químicos (BRQ) para el reaprovechamiento de sus residuos generados. Si los residuos no pueden ser reaprovechados, deberán realizar un tratamiento de los mismos con la finalidad de desactivarlos para su disposición final. No se debe olvidar que los costos asociados al manejo de los productos químicos tienen que incluir los costos de gestión y manejo de los residuos. / The educative institutions and the companies of services that count on compatible laboratories of chemistry, in order to bring chemical experiences of laboratory or analyses as a part of a service to third, require, like the productive companies, of an appropriate management and handling of their chemical wastes.
145

Metodologia para automação de inspeção visual de bolsas para coleta de sangue / Methodology to automation visual inspection for blood bags

Cássio Avelino Adorni 28 July 2008 (has links)
As bolsas para coleta de sangue necessitam cuidados técnicos que assegurem sua esterilidade biológica durante o processo de fabricação até a entrega do produto final. As bolsas para coleta de sangue não devem conter qualquer tipo de resíduo, para que o seu uso ou conteúdo não seja comprometido causando diversos transtornos. É preciso eliminar o risco de contaminação; no entanto muitas empresas fazem a inspeção de bolsas para coleta de sangue visualmente, a olho nu, por funcionários treinados no uso de equipamento simples, o qual não pode garantir que todas as bolsas estejam livres de resíduos, por depender do fator humano. Para assegurar a esterilização das bolsas comercializadas, este trabalho propõe uma metodologia para automação de um sistema de visão computacional baseado em conjunto de técnica de extração de características de imagens e reconhecimento de padrões para detectar resíduos em imagens de bolsas para coleta de sangue durante o processo de fabricação, e assim, melhorar a qualidade das bolsas comercializadas. Os resíduos encontrados nas imagens capturadas se apresentam como componentes de alta freqüência. A metodologia proposta utiliza a Transformada Wavelet (Wavelet de Haar) em dois níveis de decomposição, como filtro passa - alta para destacar as altas freqüências, e assim detectar a existência de resíduos nas imagens capturadas. Os resultados obtidos com a inspeção visual manual realizada em bolsas para coleta de sangue, mostram que existem resultados divergentes na análise de uma mesma bolsa, o que reforça a necessidade de automatização dessa tarefa para que sejam obtidos resultados mais uniformes com padrões definidos, e dessa maneira melhorar a qualidade das bolsas comercializadas para coleta de sangue. / The blood bags require technician attention to assure its biological sterility in the process of manufacture and in the final product. The blood bags must not contain any type of waste, so that its use or content is not compromised causing various disorders; it is necessary to eliminate any contamination risk; however many companies perform a visually inspection of the blood bags, by naked eye, by trained employees in the use of a simple equipment, which cannot guarantee that all the bags are residue-free because depending on the human factor. The residues showed on the pictures were characterized as high frequency components. So the proposed methodology applies two levels decomposition of Haar´s Wavelet as high pass filter to evidence high frequencies, and to evidence the residues at the pictures and to evidence the existence of residues on the captured pictures. To assure the sterilization of the commercialized blood bags, this work propose a methodology of an automated computational system based in a group of techniques of image characteristics extraction and recognition patterns to detect residues in blood bag images in the process of manufacture, in order to improve the quality of the commercialized blood bags.This technique is used as high-pass filter, to detach the high frequencies, using a Haar-wavelet in two decomposition levels. The results obtained with the manual visual inspection indicate that were found divergent results in the analysis of the same blood bag, which reinforces the necessity of the automation of this task in order to obtain more uniform results with defined standards.
146

[en] MODELLING AND FORECASTING VIA STRUCTURAL MODELS THE PRODUCTION OF POLIPROPILENO´S BAG IN SANTA CATARINA / [pt] MODELAGEM E PREVISÃO, VIA MODELOS ESTRUTURAIS DA PRODUÇÃO DE SACOS DE POLIPROPILENO EM SANTA CATARINA

SUZANA LEITAO RUSSO 19 July 2006 (has links)
[pt] Na presente dissertação, além de se expor a fundamentação teórica das Metodologias Estruturais clássica e bayesiana para previsão de séries temporais, analisou-se o comportamento de séries temporais, analizou-se o comportamento da série produção de sacos de polipropileno produzidos pela Indústria Têxtil Oeste Ltda. com observações cobrindo o período de janeiro de 1987 a junho de 1992. Na análise, através dos pacotes computacionais correspondentes: STAMP (clássico) e BATS (bayesiano), utilizou-se variáveis de intervenção e a variável exógena correspondente à produção de metros quadrados de polipropileno, cobrindo período idêntico, ou seja janeiro de 1987 a junho de 1992. Adotando como critério de decisão o erro médio quadráticas previsões no período de ajuste e da análise ex-ante feita com as seis últimas observações (janeiro a junho de 1992), para testar a capacidade extrapolativa dos modelos, escolheu-se um modelo representativo dentro de cada abordagem e em seguida foi feito um estudo comparativo de ambas. / [en] In the present dissertation, besides exposing the theoretical foundations of Structural Models (Classic and Bayesian approaches); we also analysed the series of production of propileno´s bag produced by Indústria Têxtil Oeste Ltda. with observation covering the period from January 1987 to June 1992. We used in the analysis the packages: STAMP (classical) and BATS (Bayesian), with intervention variables and the series of production of square meters of propileno as explanatory variable. As decision criterion we used the mean square error during the period of adjustment and the ex-ante analysis with the last six observation (January up to June of 1992), to test the predictive ability of the models.
147

Akutväskan inom den psykiatriska heldygnsvården : En intervjustudie / The Emergency bag within the psychiatric inpatient ward : An interview study

Gummesson, William January 2017 (has links)
Bakgrund: Patienter med psykiatrisk problematik drabbas oftare än befolkningen i övrigt av somatisk sjukdom och lever i genomsnitt kortare. Akut somatisk sjukdom uppstår även inom den psykiatriska heldygnsvården och för att patienten skall få bästa möjliga vård är det av stor vikt att sjuksköterskan är väl insatt i principerna för akut somatiskt omhändertagande. Till sin hjälp att agera vid akuta tillstånd har sjuksköterskan akutväskan samt hjärtstartaren. Sjuksköterskans kunskaper om akut somatiskt omhändertagande med hjälp av akutväskan är i mycket liten utsträckning beforskade. Syfte: Att undersöka sjuksköterskors uppfattningar om akutväskan som redskap för akut somatiskt omhändertagande inom den psykiatriska heldygnsvården. Metod: Material samlades genom semistrukturerade intervjuer av totalt sex informanter. Informanternas utsagor analyserades sedan med hjälp av en kvalitativ innehållsanalys. Resultat: Sjuksköterskornas uppfattningar akutväskan redovisas genom fyra kategorier samt tillhörande nio subkategorier. Slutsats: Sjuksköterskorna ansåg att akutväskan inte var ändamålsenlig med vilka behov de hade. Sjuksköterskans kunskap var inte på samma nivå som akutväskans avancerade innehåll. För att i framtiden kunna säkra ett patientsäkert omhändertagande med hjälp av akutväskan vid akut somatisk sjukdom bör sjuksköterskorna få hjälp att uppdatera sina kunskaper samt träna med hjälp av akutväskan. / Background: Patients with psychiatric diseases are more likely than the rest of the population to suffer physical illness. Acute somatic illness occurs within the psychiatric inpatient ward and it is of great importance that the psychiatric nurse is proficient in the principles of acute somatic care. In case of a medical emergency, the nurse has resources as the Emergency bag and the AED to help. There is very little research made regarding the knowledge of the nurse and her skills handling the Emergency bag. Aim: To examine what perceptions nurses have about the Emergency bag within the psychiatric inpatient care. Method: The data material was gathered through semi structured interviews from a total of six informants. Their stories were analysed by a qualitative content analysis. Results: The thoughts of the nurses regarding the Emergency bag are presented through four categories with nine attached sub categories. Conclusion: The nurses did not consider the Emergency bag purposive for the requirement they had at the psychiatric inpatient ward. The knowledge of the nurses was not congruent with the advanced content of the Emergency bag. To be able to maintain patient safety using the Emergency bag in a medical emergency the nurses need to update their knowledge as well as to practise using the Emergency bag.
148

Approximate string matching distance for image classification / Distance d’édition entre chaines d’histogrammes pour la classification d’images

Nguyen, Hong-Thinh 29 August 2014 (has links)
L'augmentation exponentielle du nombre d'images nécessite des moyens efficaces pour les classer en fonction de leur contenu visuel. Le sac de mot visuel (Bag-Of-visual-Words, BOW), en raison de sa simplicité et de sa robustesse, devient l'approche la plus populaire. Malheureusement, cette approche ne prend pas en compte de l'information spatiale, ce qui joue un rôle important dans les catégories de modélisation d'image. Récemment, Lazebnik ont introduit la représentation pyramidale spatiale (Spatial Pyramid Representation, SPR) qui a incorporé avec succès l'information spatiale dans le modèle BOW. Néanmoins, ce système de correspondance rigide empêche la SPR de gérer les variations et les transformations d'image. L'objectif principal de cette thèse est d'étudier un modèle de chaîne de correspondance plus souple qui prend l'avantage d'histogrammes de BOW locaux et se rapproche de la correspondance de la chaîne. Notre première contribution est basée sur une représentation en chaîne et une nouvelle distance d'édition (String Matching Distance, SMD) bien adapté pour les chaînes de l'histogramme qui peut calculer efficacement par programmation dynamique. Un noyau d'édition correspondant comprenant à la fois d'une pondération et d'un système pyramidal est également dérivée. La seconde contribution est une version étendue de SMD qui remplace les opérations d'insertion et de suppression par les opérations de fusion entre les symboles successifs, ce qui apporte de la souplesse labours et correspond aux images. Toutes les distances proposées sont évaluées sur plusieurs jeux de données tâche de classification et sont comparés avec plusieurs approches concurrentes / The exponential increasing of the number of images requires efficient ways to classify them based on their visual content. The most successful and popular approach is the Bag of visual Word (BoW) representation due to its simplicity and robustness. Unfortunately, this approach fails to capture the spatial image layout, which plays an important roles in modeling image categories. Recently, Lazebnik et al (2006) introduced the Spatial Pyramid Representation (SPR) which successfully incorporated spatial information into the BoW model. The idea of their approach is to split the image into a pyramidal grid and to represent each grid cell as a BoW. Assuming that images belonging to the same class have similar spatial distributions, it is possible to use a pairwise matching as similarity measurement. However, this rigid matching scheme prevents SPR to cope with image variations and transformations. The main objective of this dissertation is to study a more flexible string matching model. Keeping the idea of local BoW histograms, we introduce a new class of edit distance to compare strings of local histograms. Our first contribution is a string based image representation model and a new edit distance (called SMD for String Matching Distance) well suited for strings composed of symbols which are local BoWs. The new distance benefits from an efficient Dynamic Programming algorithm. A corresponding edit kernel including both a weighting and a pyramidal scheme is also derived. The performance is evaluated on classification tasks and compared to the standard method and several related methods. The new method outperforms other methods thanks to its ability to detect and ignore identical successive regions inside images. Our second contribution is to propose an extended version of SMD replacing insertion and deletion operations by merging operations between successive symbols. In this approach, the number of sub regions ie. the grid divisions may vary according to the visual content. We describe two algorithms to compute this merge-based distance. The first one is a greedy version which is efficient but can produce a non optimal edit script. The other one is an optimal version but it requires a 4th degree polynomial complexity. All the proposed distances are evaluated on several datasets and are shown to outperform comparable existing methods.
149

Real-time Hand Gesture Detection and Recognition for Human Computer Interaction

Dardas, Nasser Hasan Abdel-Qader January 2012 (has links)
This thesis focuses on bare hand gesture recognition by proposing a new architecture to solve the problem of real-time vision-based hand detection, tracking, and gesture recognition for interaction with an application via hand gestures. The first stage of our system allows detecting and tracking a bare hand in a cluttered background using face subtraction, skin detection and contour comparison. The second stage allows recognizing hand gestures using bag-of-features and multi-class Support Vector Machine (SVM) algorithms. Finally, a grammar has been developed to generate gesture commands for application control. Our hand gesture recognition system consists of two steps: offline training and online testing. In the training stage, after extracting the keypoints for every training image using the Scale Invariance Feature Transform (SIFT), a vector quantization technique will map keypoints from every training image into a unified dimensional histogram vector (bag-of-words) after K-means clustering. This histogram is treated as an input vector for a multi-class SVM to build the classifier. In the testing stage, for every frame captured from a webcam, the hand is detected using my algorithm. Then, the keypoints are extracted for every small image that contains the detected hand posture and fed into the cluster model to map them into a bag-of-words vector, which is fed into the multi-class SVM classifier to recognize the hand gesture. Another hand gesture recognition system was proposed using Principle Components Analysis (PCA). The most eigenvectors and weights of training images are determined. In the testing stage, the hand posture is detected for every frame using my algorithm. Then, the small image that contains the detected hand is projected onto the most eigenvectors of training images to form its test weights. Finally, the minimum Euclidean distance is determined among the test weights and the training weights of each training image to recognize the hand gesture. Two application of gesture-based interaction with a 3D gaming virtual environment were implemented. The exertion videogame makes use of a stationary bicycle as one of the main inputs for game playing. The user can control and direct left-right movement and shooting actions in the game by a set of hand gesture commands, while in the second game, the user can control and direct a helicopter over the city by a set of hand gesture commands.
150

Unsupervised Entity Classification with Wikipedia and WordNet / Klasifikace entit pomocí Wikipedie a WordNetu

Kliegr, Tomáš January 2007 (has links)
This dissertation addresses the problem of classification of entities in text represented by noun phrases. The goal of this thesis is to develop a method for automated classification of entities appearing in datasets consisting of short textual fragments. The emphasis is on unsupervised and semi-supervised methods that will allow for fine-grained character of the assigned classes and require no labeled instances for training. The set of target classes is either user-defined or determined automatically. Our initial attempt to address the entity classification problem is called Semantic Concept Mapping (SCM) algorithm. SCM maps the noun phrases representing the entities as well as the target classes to WordNet. Graph-based WordNet similarity measures are used to assign the closest class to the noun phrase. If a noun phrase does not match any WordNet concept, a Targeted Hypernym Discovery (THD) algorithm is executed. The THD algorithm extracts a hypernym from a Wikipedia article defining the noun phrase using lexico-syntactic patterns. This hypernym is then used to map the noun phrase to a WordNet synset, but it can also be perceived as the classification result by itself, resulting in an unsupervised classification system. SCM and THD algorithms were designed for English. While adaptation of these algorithms for other languages is conceivable, we decided to develop the Bag of Articles (BOA) algorithm, which is language agnostic as it is based on the statistical Rocchio classifier. Since this algorithm utilizes Wikipedia as a source of data for classification, it does not require any labeled training instances. WordNet is used in a novel way to compute term weights. It is also used as a positive term list and for lemmatization. A disambiguation algorithm utilizing global context is also proposed. We consider the BOA algorithm to be the main contribution of this dissertation. Experimental evaluation of the proposed algorithms is performed on the WordSim353 dataset, which is used for evaluation in the Word Similarity Computation (WSC) task, and on the Czech Traveler dataset, the latter being specifically designed for the purpose of our research. BOA performance on WordSim353 achieves Spearman correlation of 0.72 with human judgment, which is close to the 0.75 correlation for the ESA algorithm, to the author's knowledge the best performing algorithm for this gold-standard dataset, which does not require training data. The advantage of BOA over ESA is that it has smaller requirements on preprocessing of the Wikipedia data. While SCM underperforms on the WordSim353 dataset, it overtakes BOA on the Czech Traveler dataset, which was designed specifically for our entity classification problem. This discrepancy requires further investigation. In a standalone evaluation of THD on Czech Traveler dataset the algorithm returned a correct hypernym for 62% of entities.

Page generated in 0.0436 seconds