The growing presence of the Internet in day-to-day tasks, along with the evolution of computational systems, contributed to increase data exposure. This scenario highlights the need for safer user authentication systems. An alternative to deal with this is by the use of biometric systems. However, biometric features may change over time, an issue that can affect the recognition performance due to an outdated biometric reference. This effect can be called as template ageing in the area of biometrics and as concept drift in machine learning. It raises the need to automatically adapt the biometric reference over time, a task performed by adaptive biometric systems. This thesis studied adaptive biometric systems considering biometrics in a data stream context. In this context, the test is performed on a biometric data stream, in which the query samples are presented one after another to the biometric system. An adaptive biometric system then has to classify each query and adapt the biometric reference. The decision to perform the adaptation is taken by the biometric system. Among the biometric modalities, this thesis focused on behavioural biometrics, particularly on keystroke dynamics and on accelerometer biometrics. Behavioural modalities tend to be subject to faster changes over time than physical modalities. Nevertheless, there were few studies dealing with adaptive biometric systems for behavioural modalities, highlighting a gap to be explored. Throughout the thesis, several aspects to enhance the design of adaptive biometric systems for behavioural modalities in a data stream context were discussed: proposal of adaptation strategies for the immune-based classification algorithm Self-Detector, combination of genuine and impostor models in the Enhanced Template Update framework and application of score normalization to adaptive biometric systems. Based on the investigation of these aspects, it was observed that the best choice for each studied aspect of the adaptive biometric systems can be different depending on the dataset and, furthermore, depending on the users in the dataset. The different user characteristics, including the way that the biometric features change over time, suggests that adaptation strategies should be chosen per user. This motivated the proposal of a modular adaptive biometric system, named ModBioS, which can choose each of these aspects per user. ModBioS is capable of generalizing several baselines and proposals into a single modular framework, along with the possibility of assigning different adaptation strategies per user. Experimental results showed that the modular adaptive biometric system can outperform several baseline systems, while opening a number of new opportunities for future work. / A crescente presença da Internet nas tarefas do dia a dia, juntamente com a evolução dos sistemas computacionais, contribuiu para aumentar a exposição dos dados. Esse cenário evidencia a necessidade de sistemas de autenticação de usuários mais seguros. Uma alternativa para lidar com isso é pelo uso de sistemas biométricos. Contudo, características biométricas podem mudar com o tempo, o que pode afetar o desempenho de reconhecimento devido a uma referência biométrica desatualizada. Esse efeito pode ser chamado de template ageing na área de sistemas biométricos adaptativos ou de mudança de conceito em aprendizado de máquina. Isso levanta a necessidade de adaptar automaticamente a referência biométrica com o tempo, uma tarefa executada por sistemas biométricos adaptativos. Esta tese estudou sistemas biométricos adaptativos considerando biometria em um contexto de fluxo de dados. Neste contexto, o teste é executado em um fluxo de dados biométrico, em que as amostras de consulta são apresentadas uma após a outra para o sistema biométrico. Um sistema biométrico adaptativo deve então classificar cada consulta e adaptar a referência biométrica. A decisão de executar a adaptação é tomada pelo sistema biométrico. Dentre as modalidades biométricas, esta tese foca em biometria comportamental, em particular em dinâmica da digitação e em biometria por acelerômetro. Modalidades comportamentais tendem a ser sujeitas a mudanças mais rápidas do que modalidades físicas. Entretanto, havia poucos estudos lidando com sistemas biométricos adaptativos para modalidades comportamentais, destacando uma lacuna para ser explorada. Ao longo da tese, diversos aspectos para aprimorar o projeto de sistemas biométricos adaptativos para modalidades comportamentais em um contexto de fluxo de dados foram discutidos: proposta de estratégias de adaptação para o algoritmo de classificação imunológico Self-Detector, combinação de modelos genuíno e impostor no framework do Enhanced Template Update e aplicação de normalização de scores em sistemas biométricos adaptativos. Com base na investigação desses aspectos, foi observado que a melhor escolha para cada aspecto estudado dos sistemas biométricos adaptativos pode ser diferente dependendo do conjunto de dados e, além disso, dependendo dos usuários no conjunto de dados. As diferentes características dos usuários, incluindo a forma como as características biométricas mudam com o tempo, sugerem que as estratégias de adaptação deveriam ser escolhidas por usuário. Isso motivou a proposta de um sistema biométrico adaptativo modular, chamado ModBioS, que pode escolher cada um desses aspectos por usuário. O ModBioS é capaz de generalizar diversos sistemas baseline e propostas apresentadas nesta tese em um framework modular, juntamente com a possibilidade de atribuir estratégias de adaptação diferentes por usuário. Resultados experimentais mostraram que o sistema biométrico adaptativo modular pode superar diversos sistemas baseline, enquanto que abre um grande número de oportunidades para trabalhos futuros.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-11-26T10:24:30Z No. of bitstreams: 2 Dissertação - Leomar Rufino Alves Júnior - 2015.pdf: 5358486 bytes, checksum: 65b930c6a83152c4867b2f00eb5865b2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-11-27T07:27:21Z (GMT) No. of bitstreams: 2 Dissertação - Leomar Rufino Alves Júnior - 2015.pdf: 5358486 bytes, checksum: 65b930c6a83152c4867b2f00eb5865b2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-11-27T07:27:21Z (GMT). No. of bitstreams: 2 Dissertação - Leomar Rufino Alves Júnior - 2015.pdf: 5358486 bytes, checksum: 65b930c6a83152c4867b2f00eb5865b2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-03-13 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / This research aimed to verify the precision and accuracy of orthomosaics and Digital Surface Model (DSM) generated automatically by aerial photography taken with an Unmanned Aerial Vehicle (UAV) in urban and rural areas at the cities of Goiânia, Goiás and Edéia, all located in the state of Goiás. The survey also verified for the influence of the scale, depending on the flight height, the influence of the sunlight, and the phenological analysis obtained in agricultural areas with sugarcane and corn (vegetative cycle) crops. Flight plans were drawn up in E-mo-tion software provided by Sensefly - Swiss company manufacturer of UAV Swinglet CAM used in this work. The camera on board UAV was the Canon IXUS 220 HS, with a spatial resolution of 12.1 megapixel, CMOS sensor equipped with type 1 / 2.3" (4000 x 3000 pixel), pixel pitch of 1.54 m, and focal distance equivalent of 35 mm. To check the precision and accuracy of orthomosaics in urban areas, the flights were uniformly distributed in the study area with three-dimensional coordinates pre-marked targets read in the orthomosaic itself, and compared with the coordinates obtained by RTK and static fast positioning methods geodetic survey, using a pair of GNSS signal receiver. Evaluation of Cartographic Accuracy Standards (PEC, defined by the Brazilian decree, no. 89817 of June 20, 1984) was performed by discrepancies between these coordinates. The bias was analyzed by student's t test and the accuracy with the chi-square probability. We have found that in those orthomosaics performed over the urban area in Goiânia city, some buildings were not properly processed in terms of the conical to orthogonal projection; this product was classified as PEC Class A to the 1/250 scale. In Goiás city, the generated orthomosaics without support points were classified as PEC Class A to the 1/2,500 scale, while the orthomosaic generated with eight supporting points was classified as PEC Class A to the 1/1,125 scale. The orthomosaic and MDS generated without ground supporting points presented planialtimetric trends. The mean difference calculated in the orthomosaic with ground supporting was 54 times lower on the E axis, and 111 times lower in N axis, and 10 times lower in the Z axis relative to the average of the discrepancies in orthomosaic without ground control points. The MDS generated with and without supporting showed vertical displacement trend. Thus it was evident the need for supporting points for making orthomosaics and MDS obtained with UAV. In flights performed in crop areas, it was observed that for a better estimate of MPRI vegetation index, the photographs needs to with larger scales (GSD of 5 cm), even with a higher software difficulty in finding homologous points. It did not occur when we used pictures with smaller scales (GSD 20 cm, or larger) for the generation of orthomosaics and MDS. / Esta pesquisa teve por objetivo verificar a precisão e acurácia dos ortomosaicos e Modelo Digital de Superfície (MDS) gerados automaticamente por programa de aerofotogrametria, utilizando fotografias aéreas tomadas com um Veículo Aéreo Não Tripulado (VANT) em áreas urbanas e rurais das cidades de Goiânia, Goiás e Edéia, todas no estado de Goiás. A pesquisa também verificou a influência da escala, em função da altura de voo, a influência da iluminação solar e a análise fenológica em ortomosaicos obtidos em áreas agrícolas com cultivo de cana-de-açúcar e milho (clico vegetativo). Os planos de voo foram elaborados no programa E-mo-tion, fornecido pela Sensefly – empresa suíça fabricante do VANT Swinglet CAM utilizado nesse trabalho. A câmara instalada no VANT foi a Canon IXUS 220 HS, com resolução espacial de 12,1 megapixel, equipada com sensor tipo CMOS 1/2,3” (4000 x 3000 pixel), pixel pitch de 1,54 m, e distância focal equivalente de 35 mm. Para verificar a precisão e acurácia dos ortomosaicos, nas áreas urbanas, foram uniformemente distribuídos nas áreas de estudo alvos pré-sinalizados, com coordenadas tridimensionais lidas nos ortomosaicos e comparadas com as coordenadas obtidas por levantamento geodésico nos métodos de posicionamento RTK e estático rápido, utilizando-se um par de receptor de sinais GNSS. A avaliação do Padrão de Exatidão Cartográfica (PEC) foi realizada pelas discrepâncias entre essas coordenadas. A tendenciosidade foi analisada pelo teste t de Student e a precisão pela probabilidade do qui-quadrado, considerando o ortomosaico Classe A conforme PEC estabelecido no Decreto nº 89.817 de 20.06.1984. Verificou-se que nos ortomosaicos oriundos do aerolevantamento realizado na área urbana (Goiânia), algumas edificações não foram devidamente transformadas da projeção cônica para a ortogonal. Os ortomosaicos gerados com mais de 8 pontos de controle foram classificados como Classe A para a escala de 1/250. Verificou-se, também, que o ortomosaico sem pontos de apoio, oriundo dos aerolevantamentos realizados na cidade de Goiás, foi classificado como Classe A na escala 1/2.500, enquanto o ortomosaico gerado com oito pontos de apoio foi classificado como Classe A na escala de 1/1.125, conforme parâmetros de precisão e exatidão estabelecidos por este mesmo Decreto Federal. O ortomosaico e MDS gerados sem pontos de apoio apresentaram tendência planialtimétrica. As médias das discrepâncias calculadas no ortomosaico com apoio foi 54 vezes menor no eixo E, 111 vezes menor no eixo N e 10 vezes menor no eixo Z, em relação à média das discrepâncias no ortomosaico sem pontos de apoio. O MDS gerado com e sem apoio apresentaram tendência de deslocamento vertical. Ficou evidente a necessidade de utilizar pontos de apoio para a confecção de ortomosaicos e MDS obtidos com VANT. Em relação aos voos realizados em áreas de cultivo observou-se que para uma melhor estimativa do MPRI observou-se que na geração de ortomosaicos a partir de fotografias com escalas maiores (GSD de 5 cm), o programa de processamento das fotografias teve dificuldade em encontrar os pontos homólogos necessários à geração dos ortomosaicos. Fato que não ocorreu quando se utilizou fotografias com escalas menores (GSD de 20 cm) para a geração dos ortomosaicos e MDS.

Informationen des Universitätsrechenzentrums

Informationen des Universitätsrechenzentrums

Many embedded systems are complex, and it is often required that the firmware in these systems are updatable by the end-user. For economical and confidentiality reasons, it is important that these systems only accept firmware approved by the firmware producer. This thesis work focuses on creating a security enhanced firmware update procedure that is suitable for use in embedded systems. The common elements of embedded systems are described and various candidate algorithms are compared as candidates for firmware verification. Patents are used as a base for the proposal of a security enhanced update procedure. We also use attack trees to perform a threat analysis on an update procedure. The results are a threat analysis of a home office router and the proposal of an update procedure. The update procedure will only accept approved firmware and prevents reversion to old, vulnerable, firmware versions. The firmware verification is performed using the hash function SHA-224 and the digital signature algorithm RSA with a key length of 2048. The selection of algorithms and key lengths mitigates the threat of brute-force and cryptanalysis attacks on the verification algorithms and is believed to be secure through 2030.

There are no guidelines regarding how companies should design status updates on Facebook which attain good readability and engage the readers. Half the Swedish population are Facebook-users, but companies have yet to publish comprehensible messages on Facebook which effectively include the recipients. Inclusion is not just a matter of accessibility, but also of readability. Therefore, I studied how status updates should be designed on Facebook in order to increase the readability and to engage the readers. My target group is 22-32 year olds, since the company I worked with wanted to target this group. I conducted my research through literature studies, interviews with the client, analysis of past status updates, questioned an expert in social media, and organized a group interview with the target group. My research shows that status updates should contain information that is topical, informative and relevant to the target group. However, status updates should not contain too much information, since messages that are saturated with information are difficult for the audience to interact with. Status updates should be written seriously and give the readers an added value. The message should contain 50-250 characters. If the audience is unfamiliar with the subject in the status update, a longer message may be necessary. Nonetheless, status updates should not exceed 400 characters, as the readers will then lose interest. Status updates should be written in a simple and informal language. Communication on Facebook requires specific guidelines, since social media differs from traditional media. The texts published here must be specifically adapted to Facebook. This requires an increased understanding of the demands Facebook as a medium puts on texts published on this social utility. Further research could therefore explore the way in which people read on Facebook, for example by using eye-tracking cameras. / Det saknas riktlinjer för hur företag ska utforma läsbara statusuppdateringar på Facebook som engagerar läsarna. För att företag ska kunna inkludera sina mottagare kan de inte förlita sig på Facebooks fysiska tillgänglighet. Informationen som företag publicerar på Facebook måste också göras begriplig för läsarna. Därför studerade jag hur statusuppdateringar bör utformas på Facebook för att få hög läsbarhet och för att engagera läsarna. Min målgrupp är 22-32-åringar, eftersom företaget jag arbetade mot ville nå ut till denna grupp. Genom litteraturstudier, intervjuer med uppdragsgivaren, analys av tidigare statusuppdateringar, att ställa frågor till en expert på sociala medier samt genom en gruppintervju med målgruppen kom jag fram till mitt resultat. Min undersökning visar att innehållet i en statusuppdatering ska vara aktuellt, informativt och relevant för målgruppen. Statusuppdateringar får inte vara för uttömmande. De ska vara seriösa och ge läsaren ett mervärde. En statusuppdatering bör omfatta 50-250 tecken. Om läsarens är obekant med ämnet i uppdateringen kan den även vara längre. Statusuppdateringar bör dock inte överstiga 400 tecken, eftersom läsaren förlorar intresset då. Språket i en statusuppdatering får vara ledigt, men måste vara tydligt. Särskilda riktlinjer behövs för kommunikation på Facebook, eftersom sociala medier fungerar annorlunda än traditionella medier. De texter som publiceras på Facebook måste anpassas för Facebook. Därför krävs en bättre förståelse för de krav Facebook som medium ställer på texterna som publiceras där. Vidare forskning kunde därför studera hur människor läser på Facebook, exempelvis med hjälp av ögonrörelsekamera.

Les nouvelles générations de radars sont confrontées à des cibles de plus en plus menaçantes. Ces radars doivent effectuer plusieurs tâches en parallèle, dont la veille et la poursuite. Pour cela, ils peuvent être équipés de panneaux fixes, pour éviter les contraintes liées à la rotation de l'antenne. Le pistage du radar doit donc être renouvelé pour répondre à la double difficulté posée par le pistage des cibles très manoeuvrantes et la gestion des ressources. Dans ce contexte, cette thèse étudie de nouvelles méthodes de pistage pour les cibles hyper-manoeuvrantes. Un nouveau modèle de cible, en coordonnées intrinsèques, est proposé. Ce modèle est exprimé directement dans le repère de la cible, afin de décrire au mieux des manoeuvres fortes avec des accélérations normales bien supérieures à la gravité terrestre. Un algorithme de filtrage utilisant la formulation intrinsèque du modèle est développé. Cet algorithme ayant la même structure qu'une filtre de Kalman étendu, il a été testé sur de vraies données. La comparaison avec d'autres algorithmes de filtrage a montré de réelles améliorations sur un ensemble important de trajectoires. Une nouvelle méthode d'estimation, reposant sur la formulation en termes de moindres carrés de l'approche de lissage, et permettant de tenir compte de sauts dans la trajectoire est également proposée, et les bénéfices sur des méthodes plus classiques de sauts entre modèles sont montrés. Indépendamment, le problème de cadence adaptative est également traité. Un algorithme très général permettant d'optimiser la cadence de mesure pour ménager le budget temps du radar pour la surveillance est présenté. / The new generation of radars is facing increasingly threatening targets. These radars are asked to perform several tasks in parallel, including surveillance and tracking. To this aim, they can be equipped with staring antennas, so they overcome the constraints induced by the rotation of the antenna. The tracking function of the radar has thus to be upgraded to respond to the double issue of tracking highly manoeuvring targets and managing the resources to balance time between tasks. In this context, this thesis investigates new means of tracking highly manoeuvring targets. A new target model based on intrinsic coordinates to perform target tracking is proposed. This new target model is expressed in the frame of the target itself, and uses the Frenet-Serret frame, which is well suited to the description of highly dynamic manoeuvres involving normal accelerations that are much larger than earth gravity. A filtering algorithm using the special intrinsic formulation of the target model is developed. This filtering algorithm is very similar in terms of implementation to an Extended Kalman filter, and was implemented using real data. The comparison with standard target models and filtering algorithms show improvements over simple models and algorithms on a large set of trajectories. A new estimation method, relying on the least squares formulation of the smoothing approach, and taking into account kinematic jumps in the trajectory is also developed. This method also shows improvements over a set of common algorithms based on standard manoeuvre detection. And independently, we investigate the issue of update rate adaptation for radar measurements. A very general update rate adaptation algorithm is derived to optimise the time of revisit of each target, allowing to preserve the radar time budget for other tasks simultaneously performed, such as surveillance.

Master´s thesis is considered with design of algorithms for new module of company information system. In the beginning of thesis there are characterized types of ways to describe an information systems. For specification of described system is briefly defined IBM Lotus Notes environment. Next chapter is about object-oriented analysis and design of a module of information system by using UML´s diagrams in modeling tool Enterprise Architect. In the third chapter is made analysis and design of module´s connection with current system, specificly update data in form. Thesis shows designed algorithms in environment of Lotus Domino Designer by using LotusScript and SQL languages and Lotus Domino Connector for access into the database by using ODBC. In last part of thesis is proposed to use a mapping tool to mapp the ITC infrastructure by using Change management process according to ITIL method, to manage all the changes in developing system effectively.

First, we consider different kinds of representation of uncertainty and the meth- ods for updating each of them by conditioning. We focus on the generic frame- work of (conditional) plausibility spaces, since it generalises all the introduced representations. Further, we select three frameworks and list the properties that need to be added to a conditional plausibility space in order to recover each of these frameworks. The main goal of this work, however, is to show how public announcement on single-agent plausibility models, ranking structures, and pos- sibility structures realised by their corresponding update mechanisms, can be embedded into the framework of conditional plausibility spaces. At the very end we briefly illustrate a general update model using plausibility measures. Keywords: belief revision, dynamic logic, epistemic logic, plausibility space, pub- lic announcement, uncertainty, update.

High-performance programs and systems require concurrency to take full advantage of available hardware. However, the available concurrent programming models force a difficult choice, between simple models such as mutual exclusion that produce little to no concurrency, or complex models such as Read-Copy Update that can scale to all available resources. Simple concurrent programming models enforce atomicity and causality, and this enforcement limits concurrency. Scalable concurrent programming models expose the weakly ordered hardware memory model, requiring careful and explicit enforcement of causality to preserve correctness, as demonstrated in this dissertation through the manual construction of a scalable hash-table item-move algorithm. Recent research on "relativistic programming" aims to standardize the programming model of Read-Copy Update, but thus far these efforts have lacked a generalized memory ordering model, requiring data-structure-specific reasoning to preserve causality. I propose a new memory ordering model, "relativistic causal ordering", which combines the scalabilty of relativistic programming and Read-Copy Update with the simplicity of reader atomicity and automatic enforcement of causality. Programs written for the relativistic model translate to scalable concurrent programs for weakly-ordered hardware via a mechanical process of inserting barrier operations according to well-defined rules. To demonstrate the relativistic causal ordering model, I walk through the straightforward construction of a novel concurrent hash-table resize algorithm, including the translation of this algorithm from the relativistic model to a hardware memory model, and show through benchmarks that the resulting algorithm scales far better than those based on mutual exclusion.