Duisburg, Essen, University Diss., 2005.

Dans ce mémoire, une nouvelle approche neuronale TLS EXIN est proposée pour estimer la position d'un récepteurGPS. L'idée générale de cette approche est d'avoir une méthode plus robuste pour le calcul de la position.Le pseudorange alone est l'une des techniques les plus simples et les plus utilisées pour le positionnement GPS.Cette technique nécessite la résolution d'un système surdéterminé d'équations linéaires Ax+/-b. En général, lesmoindres carrés ordinaires (OLS) et les moindres carrés pondérés (WLS) sont les méthodes couramment utiliséespour estimer la position d'un récepteur grâce à leur rapidité et leur robustesse, mais la structure particulière de lamatrice de données A et les bruits affectant ses entrées ne sont pas considérés. Au contraire, cette thèse a pourobjectif d'analyser ces problèmes et d'étudier le comportement des méthodes des moindres carrés (LS) enprésence d'une matrice de données A bruitée.L'approche des moindres carrés totaux (TLS) prend en compte le bruit dans la matrice de données A ainsi que dansle vecteur d'observation b. Cette dernière est une technique moins robuste que OLS et plus sensible auchangement des données, elle est en général résolue par une méthode directe. La méthode TLS EXIN basée surles réseaux de neurones est un algorithme itératif (flux gradient) pour résoudre le problème TLS. Elle donne unmeilleur résultat parce qu'elle peut exploiter les informations d'état initial provenant des époques précédentes et, encas de conditions initiales nulles, donne une estimation précise même en cas de problème singulier.Pour réaliser des comparaisons entre les différentes méthodes des moindres carrés (LS), deux jeux de données ontété collectés. Le premier jeu de données est issu du réseau TERIA et comporte des données collectées depuisdifférentes stations de référence situées dans toute la France. Le deuxième jeu de données est le résultat d'unecampagne de mesures utilisant un appareil GPS (Ublox NL-6002U).Grâce à ces données réelles, un nombre de conditionnement bas a été estimé. Dans ce cas, toutes les méthodesLS donnent des estimations équivalentes, et le choix du meilleur algorithme (OLS, et surtout, WLS) est privilégiépour leur rapidité de calcul. Cependant, le pire scénario qui puisse se produire a été étudié (dans le cas d'unsatellite éloigné), et ont été observés des mauvais conditionnements du problème de GPS (nombre deconditionnement élevé). Cette situation extrême justifie l'utilisation du réseau neuronal TLS EXIN. Les résultatsobtenus confirment cette approche, même pour un nombre de conditionnement élevé.____________________________________________________________________________________________ / In this thesis, the neural approach TLS EXIN was proposed in a new way in order to estimate the position of a GPSreceiver. The general idea of this approach is to develop a more robust method for calculating the position.The ¿pseudorange alone¿ method is one of the simplest techniques and most widely used for estimating the GPSpositioning and it results in solving an overdetermined system of linear equations Ax¿b. In general, the ordinaryleast squares (OLS) and weighted least squares (WLS) are the commonly used methods to estimate the position ofa receiver for their quickness and robustness, but the particular structure of the data matrix A and the noise affectingits entries are not considered. This thesis, instead, aims to address these problems and study the behavior of leastsquares (LS) methods in the presence of a noisy data matrix A.The approach of total least squares (TLS) takes into account the noise in A and b. It is a less robust technique thanOLS and more sensitive to data changes. It is general solved as a direct method. Instead, the neural network TLSEXIN, which is an iterative algorithm (gradient flow) for solving TLS, works better both because it may exploit theinitial condition information derived from the previous epochs, and, in case of null initial conditions, yields anaccurate estimate even in case of close-to-degenerate data matrix.To perform tests between different methods of least squares, two sets of data were collected. The first one comesfrom the TERIA network and includes data collected from different reference stations located throughout France.While the second one is the result of a measurement campaign using GPS (Ublox NL-6002U).Using the real data, a low condition number has been estimated: in this case all LS methods yield equivalentestimates: as a consequence, OLS and WLS are to be preferred for their low computational cost. However, theworst scenario has been investigated which may occur in case of a distant satellite, resulting in the ill-conditioning ofthe GPS problem. This extreme situation justifies the use of the TLS EXIN neural network. The results obtainedconfirm of this approach even for very large condition numbers.

This thesis proposes a new problem of identifying large and tangled logic structures in a synthesized netlist. Large groups of cells that are highly interconnected to each other can often create potential routing hotspots that require special placement constraints. They can also indicate problematic clumps of logic that either require resynthesis to reduce wiring demand or specialized datapath placement. At a glance, this formulation appears similar to conventional circuit clustering, but there are two important distinctions. First, we are interested in finding large groups of cells that represent entire logic structures like adders and decoders, as opposed to clusters with only a handful of cells. Second, we seek to pull out only the structures of interest, instead of assigning every cell to a cluster to reduce problem complexity. This work proposes new metrics for detecting structures based on Rent’s rule that, unlike traditional cluster metrics, are able to fairly differentiate between large and small groups of cells. Next, we demonstrate how these metrics can be applied to identify structures in a netlist. Finally, our experiments demonstrate the ability to predict and alleviate routing hotspots on a real industry design using our metrics and method.

All living organisms are made of cells, within which genetic information is stored on long strands of deoxyribonucleic acid (DNA). The DNA encodes thousands of different genes and provides the blueprint for all of the structures and activities occurring within the cell. The building blocks of DNA are the four deoxyribonucleotides, dATP, dGTP, dTTP, and dCTP, which are collectively referred to as dNTPs. The key enzyme in the production of dNTPs is ribonucleotide reductase (RNR). In the budding yeast Saccharomyces cerevisiae, the concentrations of the individual dNTPs are not equal and it is primarily RNR that maintains this balance. Maintenance of the dNTP pool balance is critical for accurate DNA replication and DNA repair since elevated and/or imbalanced dNTP concentrations increase the mutation rate and can ultimately lead to genomic instability and cancer. In response to DNA damage, the overall dNTP concentration in S. cerevisiae increases. Cell survival rates increase as a result of the elevated concentration of dNTPs, but the cells also suffer from a concomitant increase in mutation rates. When the replication machinery encounters DNA damage that it cannot bypass, the replication fork stalls and recruits specialized translesion synthesis (TLS) polymerases that bypass the damage so that replication can continue. We hypothesized that elevated dNTP levels in response to DNA damage may allow the TLS polymerases to more efficiently bypass DNA damage. To explore this possibility, we deleted all known TLS polymerases in a yeast strain in which we could artificially increase the dNTP concentrations. Surprisingly, even though all TLS polymerases had been deleted, elevated dNTP concentrations led to increased cell survival after DNA damage. These results suggest that replicative DNA polymerases may be involved in the bypass of certain DNA lesions under conditions of elevated dNTPs. We confirmed this hypothesis in vitro by demonstrating that high dNTP concentrations result in an increased efficiency in the bypass of certain DNA lesions by DNA polymerase epsilon, a replicative DNA polymerase not normally associated with TLS activity. We asked ourselves if it would be possible to create yeast strains with imbalanced dNTP concentrations in vivo, and, if so, would these imbalances be recognized by the checkpoint control mechanisms in the cell. To address these questions, we focused on the highly conserved loop2 of the allosteric specificity site of yeast Rnr1p. We introduced several mutations into RNR1-loop2 that resulted in changes in the amino acid sequence of the protein. Each of the rnr1-loop2 mutation strains obtained had different levels of individual dNTPs relative to the others. Interestingly, all of the imbalanced dNTP concentrations led to increased mutation rates, but these mutagenic imbalances did not activate the S-phase checkpoint unless one or several dNTPs were present at concentrations that were too low to sustain DNA replication. We were able to use these mutant yeast strains to successfully correlate amino acid substitutions within loop2 of Rnr1p to specific ratios of dNTP concentrations in the cells. We also demonstrated that specific imbalances between the individual dNTP levels result in unique mutation spectra. These mutation spectra suggest that the mutagenesis that results from imbalanced dNTP pools is due to a decrease in fidelity of the replicative DNA polymerases at specific DNA sequences where they are more likely to make a mistake. The mutant rnr1-loop2 strains that we have created with defined dNTP pool imbalances will be of great value for in vivo studies of polymerase fidelity, translesion synthesis by specialized DNA polymerases, and lesion recognition by the DNA repair machinery.

Cílem této práce je vyvinout aplikaci schopnou dešifrovat zabezpečená spojení a přeposlat dešifrovaná data na jinou stanici v síti pro další analýzu.  Daná aplikace vybízí k nelegálním účelům, avšak zamýšleným použitím výsledného produktu jsou legální odposlechy. Pro tuto práci byla z množiny nástrojů vybrána aplikace SSLsplit díky jejím vlastnostem a výkonnosti. Toto rozhodnutí bylo na základě srovnávacích testů a porovnání vlastností. Pomocí vlastního certifikátu SSLsplit podepisuje certifikáty cílových serverů, které jsou vytvářené za běhu. Spuštěná aplikace běží v režimu transparentní proxy přímo na centrálním prvku dané sítě (routeru). SSLsplit provádí man-in-the-middle útok mezi klientem a serverem bez toho, aby to některá ze stran zaznamenala. Dále umožnuje dešifrovaný obsah odeslat na předem daný uzel v síti pro jeho další zpracování. Pro možnost snažší konfigurace SSLsplitu byla implementována integrace do netc rozhraní. Aplikace byla otestována za účelem zjištění jejich výkonnostních limitů. Výkonnostní testy výsledného řešení ukazují značný pokles počtu transakcí za sekundu (TPS) při použití SSLsplit v porovnání s pouhým přeposíláním provozu. Funkce zrcadlení významně neovlivňuje počet TPS ani neomezuje samotný SSLsplit. Výsledky ukazují, že SSLsplit je schopen reálného provozu s určitým omezením.

A quantificação de recursos florestais é usada para fins diversos nas ciências naturais, e depende da obtenção de dados de campo de forma precisa e rápida, e o inventário florestal tem se valido principalmente de trabalho humano manual para este fim. A tecnologia LiDAR, baseada em sistemas a laser, permite a coleta desses dados por meio da representação tridimensional do ambiente e a geração de informações espacialmente precisas dos objetos que o compõe. O sistema de varredura laser terrestre (terrestrial laser scanning - TLS) aplica essa tecnologia sob abordagem terrestre, e assim pode ser usada na representação 3D de florestas e ambientes naturais. Devido a crescente número de estudos nesse tópico atualmente o sistema TLS é capaz de fornecer métricas florestais básicas com elevada exatidão, como densidade de plantio e diâmetro à altura do peito, além de informações não obtidas pelo inventário florestal padrão, como estimativa da biomassa e índice de área foliar, entre outros. Este trabalho tem por objetivo a avalição da capacidade do sistema TLS em fornecer com exatidão métricas de árvores individuais selecionadas em dois povoamentos florestais localizados no sudeste do Brasil. Árvores de Eucalyptus sp. (n = 6) e Pinus elliottii var. elliottii (n = 5) foram submetidas à varredura e os valores obtidos pelo mapeamento 3D foram comparados com dados medidos em campo manualmente. Os resultados encontrados mostram que o algoritmo empregado na filtragem dos troncos foi eficiente no isolamento dos fustes de árvores individuais até a altura total das árvores amostradas, enquanto que o algoritmo para modelagem do tronco filtrado foi capaz de fornecer medidas de diâmetro até 50% da altura total das amostras. A exatidão das medidas de DAP pelos dados TLS foi de 0,91 cm e 2,77 cm (REQM) para Eucalyptus e Pinus, respectivamente. Os diâmetros ao longo do fuste tiveram mais exatidão no Eucalyptus (REQM = 2,75 cm e r = 0,77) do que no Pinus (REQM = 3,62 cm e r = 0,86), resultados condizentes com os encontrados em literatura. A exatidão da estimativa dos diâmetros diminuiu ao longo do fuste. O autor sugere que a influência de vento forte no momento da varredura pode ter interferido na qualidade das nuvens de pontos em relação a ruídos e na exatidão dos modelos de obtenção de diâmetros. A partir destes resultados conclui-se que, para as características ambientais e parâmetros de varreduras apresentados, o sistema TLS foi capaz de fornecer dados com exatidão aceitável, e mais estudos devem ser conduzidos buscando o entendimento e mitigação de efeitos que podem dificultar a obtenção de dados precisos nos estratos superiores do dossel florestal. / Forest resources assessment is used for diverse purposes on natural sciences, and relies on field data acquisition in fast and precise ways, and forest inventory has been relying mainly on manual human labor for that. LiDAR technology, which is based on a laser system, allows for these data acquisition through 3D representation of surroundings and the generation of espacially precise information about the objetcs within. Terrestrial laser scanning - TLS - applies this technology in a land approach, thus it can be used on the 3D representation of forests and natural scenes. Due to increasing number of studies on this subject nowadays TLS system is capable of giving basic forest metrics with high precision, as for plant density and diameter at breast height, besides information not obtained by standard inventory procedures, as biomass estimation and leaf área index, among others. This work aims the assessment of TLS capability on giving precise metrics of individual trees located at two forest stands in southeastern Brazil. Trees of Eucalyptus sp. (n = 6) and Pinus elliottii var. elliottii (n = 5) were scanned and the numbers obtained by 3D mapping were compared to manually measured field data. The results found show that the algorithms used on trunk filtration were efficient on individual trees stem isolation until total height of measured trees, while the trunk modelling algorithm was capable of giving diameters until 50% of samples total height. The precision of DBH measurements by TLS data was 0,91 cm and 2,77 cm (RMSE) for Eucalyptus and Pinus, respectivelly. Diameters along the stem were more preciselly estimated for Eucalytus trees (RMSE = 2,75 cm and r = 0,77) than for Pinus trees (RMSE = 3,62 cm and r = 0,86), results consistente with literature. The precision of diameters estimation diminished along the stem. The author suggests that the influence of intense wind by the time of scanning can have interfered on cloud point quality in the terms of noises and thus on the precision of diameter estimation modelling. From these results one can conclude that, considering the environmental aspects and scanning parameters presented, TLS system was capable on giving data with acceptable precision, and more studies must be carried searching for understanding and mitigation of effects that can difficult precise data acquisition on upper forest strata.

A quantificação de recursos florestais é usada para fins diversos nas ciências naturais, e depende da obtenção de dados de campo de forma precisa e rápida, e o inventário florestal tem se valido principalmente de trabalho humano manual para este fim. A tecnologia LiDAR, baseada em sistemas a laser, permite a coleta desses dados por meio da representação tridimensional do ambiente e a geração de informações espacialmente precisas dos objetos que o compõe. O sistema de varredura laser terrestre (terrestrial laser scanning - TLS) aplica essa tecnologia sob abordagem terrestre, e assim pode ser usada na representação 3D de florestas e ambientes naturais. Devido a crescente número de estudos nesse tópico atualmente o sistema TLS é capaz de fornecer métricas florestais básicas com elevada exatidão, como densidade de plantio e diâmetro à altura do peito, além de informações não obtidas pelo inventário florestal padrão, como estimativa da biomassa e índice de área foliar, entre outros. Este trabalho tem por objetivo a avalição da capacidade do sistema TLS em fornecer com exatidão métricas de árvores individuais selecionadas em dois povoamentos florestais localizados no sudeste do Brasil. Árvores de Eucalyptus sp. (n = 6) e Pinus elliottii var. elliottii (n = 5) foram submetidas à varredura e os valores obtidos pelo mapeamento 3D foram comparados com dados medidos em campo manualmente. Os resultados encontrados mostram que o algoritmo empregado na filtragem dos troncos foi eficiente no isolamento dos fustes de árvores individuais até a altura total das árvores amostradas, enquanto que o algoritmo para modelagem do tronco filtrado foi capaz de fornecer medidas de diâmetro até 50% da altura total das amostras. A exatidão das medidas de DAP pelos dados TLS foi de 0,91 cm e 2,77 cm (REQM) para Eucalyptus e Pinus, respectivamente. Os diâmetros ao longo do fuste tiveram mais exatidão no Eucalyptus (REQM = 2,75 cm e r = 0,77) do que no Pinus (REQM = 3,62 cm e r = 0,86), resultados condizentes com os encontrados em literatura. A exatidão da estimativa dos diâmetros diminuiu ao longo do fuste. O autor sugere que a influência de vento forte no momento da varredura pode ter interferido na qualidade das nuvens de pontos em relação a ruídos e na exatidão dos modelos de obtenção de diâmetros. A partir destes resultados conclui-se que, para as características ambientais e parâmetros de varreduras apresentados, o sistema TLS foi capaz de fornecer dados com exatidão aceitável, e mais estudos devem ser conduzidos buscando o entendimento e mitigação de efeitos que podem dificultar a obtenção de dados precisos nos estratos superiores do dossel florestal. / Forest resources assessment is used for diverse purposes on natural sciences, and relies on field data acquisition in fast and precise ways, and forest inventory has been relying mainly on manual human labor for that. LiDAR technology, which is based on a laser system, allows for these data acquisition through 3D representation of surroundings and the generation of espacially precise information about the objetcs within. Terrestrial laser scanning - TLS - applies this technology in a land approach, thus it can be used on the 3D representation of forests and natural scenes. Due to increasing number of studies on this subject nowadays TLS system is capable of giving basic forest metrics with high precision, as for plant density and diameter at breast height, besides information not obtained by standard inventory procedures, as biomass estimation and leaf área index, among others. This work aims the assessment of TLS capability on giving precise metrics of individual trees located at two forest stands in southeastern Brazil. Trees of Eucalyptus sp. (n = 6) and Pinus elliottii var. elliottii (n = 5) were scanned and the numbers obtained by 3D mapping were compared to manually measured field data. The results found show that the algorithms used on trunk filtration were efficient on individual trees stem isolation until total height of measured trees, while the trunk modelling algorithm was capable of giving diameters until 50% of samples total height. The precision of DBH measurements by TLS data was 0,91 cm and 2,77 cm (RMSE) for Eucalyptus and Pinus, respectivelly. Diameters along the stem were more preciselly estimated for Eucalytus trees (RMSE = 2,75 cm and r = 0,77) than for Pinus trees (RMSE = 3,62 cm and r = 0,86), results consistente with literature. The precision of diameters estimation diminished along the stem. The author suggests that the influence of intense wind by the time of scanning can have interfered on cloud point quality in the terms of noises and thus on the precision of diameter estimation modelling. From these results one can conclude that, considering the environmental aspects and scanning parameters presented, TLS system was capable on giving data with acceptable precision, and more studies must be carried searching for understanding and mitigation of effects that can difficult precise data acquisition on upper forest strata.

Webmail applications are very popular these days. Besides typical usage, thanks to ciphered communication, they can be used for malicious activity like confidential data loss. This thesis discusses webmail events detection based on common webmail signatures in captured network traffic. Also there will be discussed SSL/TLS interception and decryption for further data analysis. The modules in this thesis are designed and implemented for Netfox.Framework forensics analysis tool. The Netfox project is developed at FIT BUT under security research project SEC6NET.

[pt] Enquanto o uso das WLAN cresce em ritmo acelerado, inúmeros problemas relacionados à tecnologia de segurança, definida no IEEE 802.11b, têm sido abordados em publicações técnicas, apontando deficiências e vulnerabilidades, através dos quais indivíduos não autorizados podem ter acesso às informações disponibilizadas pela rede. A precariedade na autenticação, confidencialidade e integridade dos dados dos mecanismos internos do Padrão IEEE 802.11b exige a operação conjunta com o Padrão IEEE 802.1x. Esta combinação possibilita a autenticação e criptografia dos dados de forma mais eficiente e confiável. No entanto, é possível que haja sobrecarga de pacotes, devido à inserção de tráfego extra para autenticação dos usuários e criptografia das mensagens, podendo ocasionar comprometimento na performance da rede. Desta forma, avaliou-se qual a efetiva degradação no desempenho das redes IEEE 802.11b, devido à implementação dos mecanismos de segurança, sejam eles intrínsecos ao Padrão ou combinados com o Padrão IEEE 802.1x, utilizando os protocolos FTP (File Transfer Protocol) e HTTP (Hipertext Transfer Protocol). / [en] Meanwhile the use of WLAN grows in accelerate pass, a large number of problems related to the security issues in the IEEE 802.11b have been discussed in technical papers, pointing vulnerabilities and deficiencies, from where a non authorized access to the informations passing on the network could be possible. The lack of strong solutions in authentication, confidentiality, and integrity of the data in the internal mechanisms of the protocol IEEE 802.11b, demands to operate in conjunction with the protocol IEEE 802.1x. Therefore it is possible to get authentication and cryptography in a efficient and trustful manner. The amount of extra packets, inserted for authentication and cryptography of the messages, could have a negative impact in the performance of the network. A experimental measurements of the degradation of the network throughput, when the mechanisms of IEEE 802.1x are used, were done and presented here.

There is an increasing trend of Internet of Things (IoT) solutions, and more products are getting connected to the internet. It is therefore important to create a protected link to prevent malicious attacks. This report includes Transport Layer Security (TLS) to create a secure link for the Message Queuing Telemetry Transport (MQTT) protocol. This study investigates how TLS affects the performance of internal system in terms of Energy consumption and time delay. For a use case in the form of a wireless emergency stop for conveyor belt. In summary, this resulted in the fact that despite large calculation models within TLS, the protocol had a minimal impact on the overall system. This is due to the MQTT protocol which accounted for the major impact of the system. There are attacks that TLS does not provide direct protection against, among these is Denial of Service (DoS) Attacks. Furthermore this study examines other protectionsolutions such as An Intrusion prevention System (IPS). That was configured and showed promising results against DoS attacks. Where the study examines other protection solutions and the application of an Intrusion Prevention System (IPS) is configured and tested to protect against Denial of Service attacks with successful results. / Det finns en ökande trend av Internet of Things (IoT), vilket innebär att fler produkter blir anslutna till internet. Det är därför viktigt att skapa en skyddadlänk för att förhindra skadliga attacker. Denna rapport inkluderar Transport Layer Security (TLS) för att skapa en säker länk för Message Queuing Telemetry Transport (MQTT) protokollet. Denna studie undersöker hur TLS påverkar det interna systemets prestanda när det gäller energiförbrukning och tidsfördröjning. För ett användningsfall i form av ett trådlöst nödstopp för transportband. Sammanfattningsvis resulterade detta i att trots stora beräkningsmodeller inom TLS hade protokollet en minimal inverkan på det övergripande systemet. Detta beror på MQTT protokollet som stod för systemets stora inverkan. Det finns attacker som TLS inte ger direkt skydd mot, bland dessa är Denial of Service (DoS) Attacker. Dessutom undersöker denna studie andra skyddslösningar, till exempel ett intrångsförhindrande system (IPS) som sedarmera konfigurerades för användsningsfallet och visade lovande resultat mot DoS attacker.