Dissertationen zum Thema „Bot Mitigation“

Nowadays, botnet attacks that aim to overwhelm the network layer by malformed packets and other means are usually mitigated by hardware intrusion detection systems. Application layer botnet attacks, on the other hand, are still a problem. In case of web applications, these attacks contain legitimate traffic that needs to be processed. If enough bots partake in this attack, it can lead to inaccessibility of services provided and other problems, which in turn can lead to financial loss. In this thesis, we propose a detection and mitigation system that can detect botnet attacks in realtime using statistical approach. This system is divided into several modules that together cooperate on the detection and mitigation. These parts can be further expanded. During the testing phase, the system was able to capture approximately 60% of botnet attacks that often focused on spam, login attacks and also DDoS. The number of false positive addresses is below 5%.

Infrastructure projects, based on the Build-Operate-Transfer, (BOT), method, have been of interest to governments of developed and developing countries for some time, resulting in their worldwide use. Using the BOT method enables governments to reallocate risks and rewards to the private sector for larger infrastructure projects throughout the projects' operating life. In order to implement a BOT infrastructure project successfully, one of the essential requirements is to carry out a thorough analysis of risks relating to the project including the social, economic, environmental, political, legal, and the financial aspects. Due to the fact that the type of risk study required for large-scale projects is so sophisticated, and therefore expensive and time consuming, the government, due to lack of expertise and time, often obtains a project viability study from the private sector. This can cause problems in that the private sector may incur financial losses or even bankruptcy, unless the host government guarantees compensation to the losers of the bid. Because all parties have different targets which they wish to achieve from the project, a may conflict arise and cause lengthy negotiations, sometimes lasting for years which often result in the death of the project. The greatest opportunity for a successful outcome for a BOT project is obtained when the extensive efforts and costs involved in the risk study process are shared by all parties. The responsibility of the decision maker is to identify, understand and analyze the many risk factors both, qualitative, (linguistic in nature) and quantitative, that will affect funding, procurement, developing, construction and operation, before proceeding with the build stage of the project. Firstly, it is necessary to evaluate the quantitative Risk Factors subjectively, and list them in order of importance. Secondly, conduct an evaluation of the qualitative factors and since the consideration of qualitative factors is subjective, the decision maker will often limit the number of factors being evaluated possibly resulting in inconsistent results. This study proposes a decision framework, which would be useful in determining the influence of the qualitative Risk Factors on the project management of BOT infrastructure projects. A methodology is provided to enable the identification of interrelationships between the Risk Factors and their influence on the project. Using Analytical Hierarchy Process (AHP) techniques, which model the relationships between the Risk Factors, a validation of this approach will be sought using a decomposed evaluation method and also information obtained from three existing case studies, (the Channel Tunnel, Sulaibiya Wastewater Treatment and Reclamation Plant and Marsa Allam Airport). The results of the decomposed approach were compared to experts' holistic evaluations for the same case studies mentioned above. The findings indicate that the decomposed approach showed a strong correlation to the holistic approach. An evaluation of the risks for the Sulaibiya Wastewater Treatment and Reclamation Plant study is provided and suggestions made to highlight risks attached to such a project before it is actually undertaken. Using the decomposed approach enables the decision maker to see the contribution of each risk compared to all of the risks in the total project and will help to determine and subsequently minimize or preventing any risk factors and so considerably improving the risk management of the project.

Chaque jour, une guerre invisible pour les données se déroule entre les sites de commerce électronique et les acteurs qui,en siphonnent les données, sont appelés "scrapers'' . Les sites de commerce électronique détiennent les données au cœur du conflit et souhaitent les fournir uniquement aux utilisateurs légitimes. Les scrapers veulent un accès illimité et continu aux données susmentionnées pour en tirer profit. Pour atteindre cet objectif, les scrapers envoient de grandes quantités de requêtes aux sites de commerce électronique, ce qui leur cause des problèmes financiers. Cela a conduit l'industrie de la sécurité à s'engager dans une course aux armements contre les scrapers afin de créer de meilleurs systèmes pour détecter et contrer leurs activités. À l'heure actuelle, la bataille se poursuit, mais les scrapers semblent avoir le dessus, notamment grâce à leur utilisation de Proxies IP Résidentiels (RESIPs). Dans cette thèse, nous visons à rééquilibrer la balance des forces en introduisant de nouvelles techniques de détection et d'atténuation qui surmontent les limitations des méthodes actuelles. Nous proposons une technique inspirée des "pots de miel'' qui piège les scrapers en leur faisant croire qu'ils ont obtenu les données visées tandis qu'ils reçoivent des informations modifiées. Nous présentons deux nouvelles techniques de détection basées sur des mesures de réseau qui identifient les requêtes émanant de scrapers cachés derrière les infrastructures RESIP. À travers un partenariat en cours avec Amadeus IT Group, nous validons nos résultats en utilisant des données opérationnelles réelles. Conscients que les scrapers ne cesseront pas de chercher de nouvelles façons d'éviter la détection et l'atténuation, nous offrons des contributions qui peuvent aider à élaborer les prochaines armes défensives pour lutter contre les scrapers. Nous proposons une caractérisation complète des RESIPs, la plus puissante arme actuellement à la disposition des scrapers. De plus, nous examinons la possibilité d'acquérir des renseignements sur les menaces liées aux scrapers en les géolocalisant lorsqu'ils envoient des demandes via un RESIP
Every day an invisible war for data takes place between e-commerce websites and web scrapers. E-commerce websites own the data at the heart of the conflict and would like to provide it only to genuine users. Web scrapers aim to have illimited and continuous access to the above-mentioned data to capitalize on it. To achieve this goal, scrapers send large amounts of requests to e-commerce websites, causing them financial problems. This led the security industry to engage in an arms race against scrapers to create better systems to detect and mitigate their requests. At present, the battle continues, but scrapers appear to have the upper hand, thanks to the usage of Residential IP Proxies (RESIPs). In this thesis, we aim to shift the balance by introducing novel detection and mitigation techniques that overcome the limitations of current state-of-the-art methods. We propose a deceptive mitigation technique that lures scrapers into believing they have obtained their target data while they receive modified information. We present two new detection techniques based on network measurements that identify scraping requests proxied through RESIPs. Thanks to an ongoing collaboration with Amadeus IT Group, we validate our results on real-world operational data. Being aware that scrapers will not stop looking for new ways to avoid detection and mitigation, this thesis provides additional contributions that can help in building the next defensive weapons for fighting scrapers. We propose a comprehensive characterization of RESIPs, the strongest weapon currently at the disposal of scrapers. Moreover, we investigate the possibility of acquiring threat intelligence on the scrapers by geolocating them when they send requests through a RESIP

Bats are always found in heritage buildings in Hong Kong, especially the vernacular Chinese-style buildings. This is because the natural environment which suitable for bat roosting is reducing and the structure and low disturbance of the heritage buildings are suitable for bats to roost. As conservation of heritage buildings arouse more and more attention in recent years, there are more and more conservation work projects in heritage buildings too. When planning conservation work in a heritage building with the existence of bats, what are the issues to be concerned? Since bats are protected by the Wild Animals Protection Ordinance (Cap.170), it will be an offence if works to be carried out which will hurt bats and destroy their roosts. However, sometimes conservationists seem face a difficult choice in keeping the bats or carry out the conservation work. The work may impose adverse impacts to bats such as destroying their roost and disturbing them. But keeping the btas in the heritage buildings without the conservation work, the building may become dilapidated or even collapse. As there is no comprehensive bat mitigation guideline for conservation work for heritage buildings in Hong Kong. Although there are some guidelines available in Europe and USA, are they applicable in Hong Kong? The aim of this dissertation is to provide a preliminary guide for building professionals/ conservationists to handle the bat issue when planning conservation work to heritage buildings with bat existence. The facts of bats in Hong Kong is studied then followed by the examination of mitigation measures proposed by Natural England with assessments and adjustments to fit the use in Hong Kong. Two local cases are studied and evaluation of the bat mitigation has been carried out. Finally, some points to note when carrying out conservation work in heritage buildings in Hong Kong have been discussed.
published_or_final_version
Conservation
Master
Master of Science in Conservation

This study provides a comprehensive performance analysis of Wave-Adaptive Modular Vessels (WAM-V) using simulations and testing data. WAM-Vs are a new class of marine technology that build upon the advantages of lightweight, low-draft, catamaran construction. Independent suspensions above the hulls isolate the passengers and equipment from the harsh sea environment. Enhanced understanding of the relationship between suspension and vehicle performance is critical for future missions of interest to the U.S. Navy. Throughout this study, the dynamic properties of three different WAM-Vs were evaluated. A multi-body dynamics simulation was developed for the 100-ft WAM-V 'Proteus' based on an automotive 4-post shaker rig. The model was used to characterize the sensitivities of different suspension parameters and as a platform for future models. A 12-ft unmanned surface vessel (USV) was instrumented and sea trials were conducted in the San Francisco Bay. A dynamic 4-post simulation was created for the USV using displacement inputs calculated from acceleration data via a custom integration scheme. The data was used to validate the models by comparing the model outputs to sensor data from the USV. A vertical hydrodynamics testing rig was developed to investigate the interaction between the pontoons and the water surface to improve the understanding of how hydrodynamic forces affect suspension performance. A model was created to accurately simulate the hydrodynamic forces that result from vertical pontoon motion. The model was then scaled to fit a 33-ft WAM-V prototype. The 33-ft WAM-V was instrumented and sea trials were conducted in Norfolk, VA. The WAM-V's suspension was upgraded based on the testing results. A 2-post rig was also built for evaluating the 33-ft WAM-V's dynamics. Two dynamic models were made for the 33-ft WAM-V to evaluate different suspension designs. The results from this study have numerous impacts on the naval community and on the development of WAM-Vs. The methodology for testing and evaluation will allow for future WAM-V designs to be compared under controlled circumstances. The performance of WAM-Vs can then be compared against conventional platforms to determine their suitability for future missions. Simulation development will enable future WAM-Vs to be evaluated prior to undergoing sea trials. The hydrodynamic models become a powerful design tool that can be easily scaled and combined with the 4-post models. By providing the simulations and test data to future vessel designers, the designers will be able to intelligently evaluate numerous iterations early in the design phase, improving performance and safety.
Ph. D.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California
A Synthetic Beamforming antenna was built for Airborne Telemetry. Low-Noise Block-converters translated RF to IF suitable for direct analog-to-digital conversion. Then all telemetry functions were performed digitally via parallel FPGAs for 10 independent sources. Monopulse tracking and optimal diversity combination was performed using 4 antenna quadrants at two orthogonal polarizations. Novel estimation approaches drove digital demodulation, symbol- and bit- synchronization. Final telemetry outputs include: digital, analog (video), and analog IF (e.g., for downlink relay). This program has incubated several concepts that we believe have the combined potential to significantly improve the future of telemetry.

Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2016-11-09T10:49:17Z No. of bitstreams: 1 Mariana Marques Calfat.pdf: 1015342 bytes, checksum: e6813079af0a5619862081215ae600dd (MD5)
Made available in DSpace on 2016-11-09T10:49:17Z (GMT). No. of bitstreams: 1 Mariana Marques Calfat.pdf: 1015342 bytes, checksum: e6813079af0a5619862081215ae600dd (MD5) Previous issue date: 2016-09-13
The paper is a study of the doctrine of avoidable damages under the light of the Brazilian law, which, unlike other systems, does not expressly predict the existence of the burden of mitigation. It tries to insert the concept of the duty to mitigate losses in this specific context, pointing out the main features of its institution, foundations, structure and growth prospects. Synthetically, this dissertation is divided into six chapters. The first chapter, theoretical framework, consists of opening remarks on the standards surrounding mitigation. The second chapter highlights international initiatives. The third and fourth chapters deal with the implementation of duty to mitigate losses in the Brazilian civil law. The fifth chapter develops the question of assessing the reasonableness of mitigation measures. The sixth chapter moves away from the individual-patrimonial approach and proposes the inclusion of the burden of mitigation as a guideline for governing the use of social wealth, going to the economic repercussions arising from the institution of the concept. Throughout this study, it is sought to demonstrate that the law imposes a specific conduct in order to mitigate losses resulting from default, given that the institutionalization of the concept would bring greater security to the parties involved, including judges. Finally, using the method of economic analysis of the law, it was found that the rule of mitigation could be used as a guideline governing the use of social wealth, fostering cooperation that should exist between individuals in order to avoid waste of relevant economic and social resources
O trabalho consiste no estudo da doutrina dos danos evitáveis à luz do Direito brasileiro que, diferente de outros ordenamentos, não previu expressamente a existência do ônus da mitigação. Buscou-se inserir o duty to mitigate the loss em contexto próprio, assinalando as principais características do instituto, seus fundamentos, estrutura e perspectivas de expansão. Sinteticamente, esta dissertação está dividida em seis capítulos. O primeiro capítulo, referencial teórico, faz considerações iniciais sobre a norma da mitigação. O segundo capítulo destaca as iniciativas internacionais. O terceiro e quarto capítulos tratam da aplicação da norma da mitigação no direito civil brasileiro. No quinto capítulo desenvolve-se a questão da aferição da razoabilidade das medidas mitigadoras. O sexto capítulo afasta-se do enfoque individual-patrimonialista da regra e propõe a inserção do ônus da mitigação enquanto norma orientadora que disciplina o usar da riqueza social, passando-se às repercussões econômicas oriundas do instituto. Através do presente trabalho, buscou-se demonstrar que o direito impõe uma conduta no sentido de se mitigar os prejuízos decorrentes do inadimplemento, sendo certo que a positivação do instituto traria uma maior segurança às partes e aos julgadores. Por fim, utilizando-se o método da análise econômica do direito, constatou-se que a regra da mitigação pode ser utilizada enquanto norma orientadora que disciplina o usar da riqueza social, fomentando a cooperação que deve existir entre os indivíduos a fim de evitar o desperdício de recursos econômico e socialmente relevantes

Ionospheric scintillation is a phenomenon caused by varying concentrations of charged particles in the upper atmosphere that induces deep fades and rapid phase rotations in satellite signals, including GPS. During periods of scintillation, carrier tracking loops often lose lock on the signal because the rapid phase rotations generate cycle slips in the PLL. One solution to mitigating this problem is by employing decision-directed carrier recovery algorithms that achieve data wipe-off using differential bit detection techniques. Other techniques involve PLLs with variable bandwidth and variable integration times. Since nearly 60% of the GPS signal repeats between frames, this thesis explores PLLs utilizing variable integration times and decision-directed algorithms that exploit the repeating data as a training sequence to aid in phase error estimation. Experiments conducted using a GPS signal generator, software radio, and MATLAB scintillation testbed compare the bit error rate of each of the receiver models. Training-based methods utilizing variable integration times show significant reductions in the likelihood of total loss of lock.

Digital communication systems which use Orthogonal Frequency Division Multiplexing (OFDM) are now widely used and have many advantages. The main disadvantage is the requirement for highly linear analogue electronics including the high power amplifier (HPA). This requirement cannot be met in all circumstances because of the occurrence of symbols with high peak to average power ratio (PAPR). Such symbols may be non-linearly distorted by limiting. Approaches to solve this problem have been either to reduce the PAPR at the transmitter or to try to mitigate the effect of the non-linearity at the receiver. Soft-limiting, i.e. applying limiting in software prior to the HPA is a simple way to reduce the PAPR. It produces non-linear distortion which will cause an increase in the bit-error-rate (BER) at the receiver. This thesis surveys existing alternatives ways of reducing the effect of non-linearity and proposes some new ones. Two iterative receiver techniques, based on statistical analysis of the nature of the non-linearity, have been implemented and investigated. These are the ‘Bussgang Noise Cancellation’ (BNC) technique and the ‘Decision Aided Reconstruction’ (DAR) techniques. As these techniques are valid for any memory-less nonlinearity, an alternative form of limiting, named as Inverted-Wraparound (IWRAP) has been included in the BNC investigation. A new method is proposed which is capable of correcting the received time-domain samples that are clipped, once they have been identified. This is named the ‘Equation-Method’ and it works by identifying constellation symbols that are likely to be correct at the receiver. If there are a sufficient number of these and they are correctly identified, the FFT may be partitioned to produce a set of equations that may be solved for the clipped time-domain samples. The thesis proposes four enhancements to this new method which improve its effectiveness. It is shown that the best form of this method outperforms conventional techniques especially for severe clipping levels. The performance of these four enhancements is evaluated over channels with additive white Gaussian noise (AWGN) in addition to clipping distortion. A technique based on a ‘margin factor’ is designed to make these methods work more effectively in the presence of AWGN noise. A new combining algorithm referred as ‘HARQ for Clipping’ is presented where soft bit decisions are combined from multiple transmissions. ‘HARQ for Clipping’ has been combined with the best version of the Equation-Method, and the performance of this approach is evaluated in terms of the BER with different levels of AWGN. It has been compared to other approaches from the literature and was found to out-perform the BNC iterative receiver by 3dB at signal to noise ratios around 10dB. Without HARQ, the best version of the Equation-Method performs better than the BNC receiver, at signal-to-nose ratios above about 17dB.

Submitted by Odilon Jose de Oliveira Neto (professorodilon@yahoo.com.br) on 2013-09-27T20:34:42Z No. of bitstreams: 1 TESE_ODILON.pdf: 885119 bytes, checksum: 460d85982ff9b027e21ee9ef445337e1 (MD5)
Approved for entry into archive by Vera Lúcia Mourão (vera.mourao@fgv.br) on 2013-09-27T20:50:10Z (GMT) No. of bitstreams: 1 TESE_ODILON.pdf: 885119 bytes, checksum: 460d85982ff9b027e21ee9ef445337e1 (MD5)
Made available in DSpace on 2013-09-27T21:19:03Z (GMT). No. of bitstreams: 1 TESE_ODILON.pdf: 885119 bytes, checksum: 460d85982ff9b027e21ee9ef445337e1 (MD5) Previous issue date: 2013-09-20
Several attempts of negotiation of future contracts and price indexes of beef cattle in Argentina and in Uruguay were frustrated along the years. The derivatives issued failed in a short period of time due to lack of liquidity. That scenery and other particularities of the live cattle spot market turned the administration of risk of prices into a problem for the economical agents of the meat chain. In this context, the following question emerged: the cross hedging with future contracts of Brazilian live cattle in the Brazilian Securities, Commodities and Futures Exchange (BM&FBovespa) is effective for the administration of risk of prices of beef steers in the Argentinian and Uruguayan spot market? In an effort to answer this question, it was proposed to verify if it is possible to mitigate the risk of the price volatility of the spot market of Argentinian and Uruguayan beef steers through of cross hedging in the futures market for Brazilian live cattle in the BM&FBovespa. For this, it was used static and dynamic models to estimate of the optimal cross hedge ratio and effectiveness of risk mitigation. The results of the hypothesis test of risk mitigating allow to assure that there are strong empirical evidences of effectiveness of the futures market of Brazilian live cattle in protection against the prices risk of the spot market of Argentinian and Uruguayan steers. Complementarily, it was analyzed the hypothesis of the futures market efficiency. The results present empirical evidence of a stochastic relationship common in long-term between spot and futures prices, and efficiency in predicting short-term price, which suggest that the future contracts of Brazilian live cattle in the BM&FBovespa allow adequate hedge of price for the Argentinian and Uruguayan steers in spot market.
Na Argentina e no Uruguai, diversas tentativas de negociação de contratos futuros e de índice de preços de carne bovina foram frustradas ao longo dos anos, tendo os derivativos lançados fracassado, em um curto espaço de tempo, por falta de liquidez. Esse cenário, somado a outras particularidades do mercado físico da carne bovina, torna o gerenciamento de risco de preços um problema para os agentes econômicos que atuam nessa cadeia produtiva. Nesse contexto, emergiu a seguinte questão: a proteção cruzada com contratos futuros de boi gordo brasileiro da Bolsa de Valores, Mercadorias e Futuros de São Paulo (BM&FBovespa) é efetiva para a administração do risco de preços dos novilhos de corte no mercado a vista argentino e uruguaio? Com a finalidade de responder a essa questão, propôs-se a verificar se é possível mitigar o risco da volatilidade de preços no mercado a vista dos novilhos de corte argentinos e uruguaios por meio do cross hedging no mercado futuro do boi gordo brasileiro na BM&FBovespa. Para tanto, foram utilizados modelos estáticos e dinâmicos de estimação da razão de cross hedge ótima e efetividade em mitigação do risco. Os resultados do teste de hipóteses de mitigação do risco permitiram assegurar que são fortes as evidências de efetividade do mercado futuro do boi gordo brasileiro na proteção contra o risco de preços do mercado a vista dos novilhos argentinos e uruguaios. Complementarmente, verificou-se a hipótese de eficiência do mercado futuro. Os resultados apresentaram evidências de um relacionamento estocástico comum no longo prazo entre os preços a vista e futuros, e de eficiência na predição dos preços no curto prazo, o que sugere que os contratos futuros de boi gordo brasileiro da BM&FBovespa permitem uma trava adequada de cotação-preço para os novilhos argentinos e uruguaios no mercado a vista.

abstract: Exabytes of data are created online every day. This deluge of data is no more apparent than it is on social media. Naturally, finding ways to leverage this unprecedented source of human information is an active area of research. Social media platforms have become laboratories for conducting experiments about people at scales thought unimaginable only a few years ago. Researchers and practitioners use social media to extract actionable patterns such as where aid should be distributed in a crisis. However, the validity of these patterns relies on having a representative dataset. As this dissertation shows, the data collected from social media is seldom representative of the activity of the site itself, and less so of human activity. This means that the results of many studies are limited by the quality of data they collect. The finding that social media data is biased inspires the main challenge addressed by this thesis. I introduce three sets of methodologies to correct for bias. First, I design methods to deal with data collection bias. I offer a methodology which can find bias within a social media dataset. This methodology works by comparing the collected data with other sources to find bias in a stream. The dissertation also outlines a data collection strategy which minimizes the amount of bias that will appear in a given dataset. It introduces a crawling strategy which mitigates the amount of bias in the resulting dataset. Second, I introduce a methodology to identify bots and shills within a social media dataset. This directly addresses the concern that the users of a social media site are not representative. Applying these methodologies allows the population under study on a social media site to better match that of the real world. Finally, the dissertation discusses perceptual biases, explains how they affect analysis, and introduces computational approaches to mitigate them. The results of the dissertation allow for the discovery and removal of different levels of bias within a social media dataset. This has important implications for social media mining, namely that the behavioral patterns and insights extracted from social media will be more representative of the populations under study.
Dissertation/Thesis
Doctoral Dissertation Computer Science 2017

Baitul Maal Tamwil (BMT) is a community-based and cooperative microfinance approach, and combines economic and socio-religious objectives in providing financial services to poor people and helping the needy participate in a dynamic Muslim society. The study objective is to examine the development of the BMT sector in Yogyakarta and in particular to assess the role and performance of and assesses the extent to which the BMT's philosophy and modus operandi is sustainable in achieving the dual missions of poverty alleviation following Islamic principles. This study addresses research questions of how and what role of the BMT institutions, as the Islamic microfinance model in the Javanese Muslim community, and to what extent the BMT sector is sustainable.

The diploma thesis "Comparing Climate Change Adaptation Measures: The Cases of the Czech Republic, Germany and Poland" compares national adaptation strategies on climate change of the Czech Republic, Germany and Poland. These strategies represents general politics of selected states on the field of climate change adaptation and the author compares them regarding the adaptation measures they contain. For this comparison, framework based on options and recommendations provided by Intergovernmental Panel on Climate Change (IPCC) and the EU is used. Author also analyses mitigation policies of selected states and examines similarities and differences in both approaches. In conclusion author relates his findings towards existing research and using both, he introduces limited theoretical findings about possible relationship between mitigation and adaptation policies of states.