In this modern rather interconnected era, an organization’s top priority is to protect itself from major security breaches occurring frequently within a communicational environment. But, it seems, as if they quite fail in doing so. Every week there are new headlines relating to information being forged, funds being stolen and corrupt usage of credit card and so on. Personal computers are turned into “zombie machines” by hackers to steal confidential and financial information from sources without disclosing hacker’s true identity. These identity thieves rob private data and ruin the very purpose of privacy. The purpose of this project is to identify suspicious user activity by analyzing a log file which then later can help an investigation agency like FBI to track and monitor anonymous user(s) who seek for weaknesses to attack vulnerable parts of a system to have access of it. The project also emphasizes the potential damage that a malicious activity could have on the system. This project uses Hadoop framework to search and store log files for logging activities and then performs a ‘Map Reduce’ programming code to finally compute and analyze the results.

The aim of the research presented in this thesis is to investigate the use of various optimisation heuristics in the fields of automated cryptanalysis and automated cryptographic function generation. These techniques were found to provide a successful method of automated cryptanalysis of a variety of the classical ciphers. Also, they were found to enhance existing fast correlation attacks on certain stream ciphers. A previously proposed attack of the knapsack cipher is shown to be flawed due to the absence of a suitable solution evaluation mechanism. Finally, a new approach for finding highly nonlinear Boolean functions is introduced.

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No / The Versatile and Ubiquitous Secret Sharing System, a cloud data repository secure access and a web based authentication scheme. It is designed to implement the sharing, distribution and reconstruction of sensitive secret data that could compromise the functioning of an organisation, if leaked to unauthorised persons. This is carried out in a secure web environment, globally. It is a threshold secret sharing scheme, designed to extend the human trust security perimeter. The system could be adapted to serve as a cloud data repository and secure data communication scheme. A secret sharing scheme is a method by which a dealer distributes shares of a secret data to trustees, such that only authorised subsets of the trustees can reconstruct the secret. This paper gives a brief summary of the layout and functions of a 15-page secure server-based website prototype; the main focus of a PhD research effort titled ‘Cryptography and Computer Communications Security: Extending the Human Security Perimeter through a Web of Trust’. The prototype, which has been successfully tested, has globalised the distribution and reconstruction processes. / Petroleum Technology Development Fund

Made available in DSpace on 2016-03-15T19:37:57Z (GMT). No. of bitstreams: 1 RICHARD JOHN LINTULAHTI OLANDIM.pdf: 2276167 bytes, checksum: 0d3c0536034c612074740ab02558a1be (MD5) Previous issue date: 2015-06-25 / In Brazil, the broadcasting system for television content in high definition is the ISDB-Tb. Although robust, the content transmission in this system, like in any radio frequency propagation, can suffer from external attenuating factors, such as distortion by multipath propagation. One of the techniques used in radio communications for minimizing the effects of this type of distortion is the spatial diversity reception, which uses multiple antennas connected to a single receiver. The signals, received by different antennas, are combined, in a technique known as MRC or Maximal Ratio Combiner, so that the output signal-to-noise ratio is greater than the individual signal-to-noise ratios, allowing the successfully decoding of the received content, even though the individual signal in each antenna does not have sufficient quality to be decoded independently. This study aims to establish a method of spatial diversity in receiving television signals in ISDB-Tb, pondering between the advantages and disadvantages of their use in edge regions of coverage, where the reception of the Brazilian digital TV system is not yet total. / No Brasil, o sistema de radiodifusão para conteúdos televisivos em alta definição é o ISDB-Tb. Apesar de robusto, a transmissão de conteúdos neste sistema, como qualquer propagação em radiofrequência, pode sofrer com fatores externos atenuantes, como por exemplo a distorção por propagação em multi-percurso. Uma das técnicas utilizadas em radiocomunicação para que se minimizem os efeitos deste tipo de distorção é a diversidade espacial na recepção, que utiliza múltiplas antenas conectadas a um mesmo receptor. Os sinais, recebidos pelas diferentes antenas, são trabalhados em uma técnica conhecida como MRC ou Combinação de Máxima Razão, de modo que a relação sinal-ruído de saída seja maior do que as relações sinal-ruído individuais, permitindo a decodificação do conteúdo com sucesso, mesmo que os sinais individuais em cada antena não tenham qualidade suficiente para serem decodificados independentemente. Este estudo tem como objetivo propor um método de diversidade espacial na recepção de sinais televisivos no padrão brasileiro ISDB-Tb, ponderando entre as vantagens e desvantagens de sua utilização em regiões de borda de cobertura, onde a recepção do sistema brasileiro de TV digital ainda não é total.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The RAH-66 Comanche flight test program required a state of the art Airborne Data Acquisition System consisting of: 1) A modular distributed system that uses a series of software programmable building blocks capable of signal conditioning all types of sensors. 2) A digital multiplexing system capable of combining various types of digital streams at high rates including Synchronous and Asynchronous PCM, MIL-STD-1553B, and RS-422 data streams. 3) A Data Combiner Unit that accepts synchronous PCM data streams from one to eight sources at 4 MBPS or less and a frame size of up to 8128 words each that outputs four independent PCM streams at 8 MBPS or less and a frame size of up to 16384 words. 4) A Data System Control Unit that controls the tape recorder, serves as the interface to the Pilot’s Control Unit and monitors/reports status of the data acquisition system to the Pilots Control Unit. 5) An Airborne Computer that provides the control and interface to the pilot & copilot instrumentation displays. 6) A Cockpit Instrumentation Pilot Display System consisting of a Main Unit Multi- Function Display, a Load Factor/Hub Moment Display and a Right Wing Flight Control Position Display. The Main Unit Multi-Function Display has the capability to display multiple graphic pages generated by the Airborne Computer. 7) The ability to record high speed avionics buses from the (Mission Equipment Package) MEP such as MIL-STD-1553B, (High Speed Data Bus) HSDB, (Processor Interconnect) PI Bus, (Data Flow Network) DFN and PCM utilizing the Ampex DCRsi-107 Tape Recorder.

This paper presents an overview of the research work currently being performed within the frame of project DAAB and its successor DAAB-TX towards the integration of ultra-wideband transceivers operating at mm-wave frequencies and capable of data rates up to 100 Gbits–¹. Two basic systemarchitectures are being considered: integrating a broadband antenna with a distributed amplifier and integrate antennas centered at adjacent frequencies with broadband active combiners or dividers. The paper discusses in detail the design of such systems and their components, fromthe distributed amplifiers and combiners, to the broadband silicon antennas and their single-chip integration. All components are designed for fabrication in a commercially available SiGe:C BiCMOS technology. The presented results represent the state of the art in their respective areas: 170 GHz is the highest reported bandwidth for distributed amplifiers integrated in Silicon; 89 GHz is the widest reported bandwidth for integrated-system antennas; the simulated performance of the two antenna integrated receiver spans 105 GHz centered at 148GHz, which would improve the state of the art by a factor in excess of 4 even against III-V implementations, if confirmed by measurements.

This diploma thesis deals with optimization of transmitter amplifier parameters for LoRaWAN network. The issue of optimization is first based on the conditions of ETSI EN 300 220, which takes into account the eventuality of interference the adjacent channels in the band. The optimizations are designed specifically for the Qorvo RF5110g integrated circuit, so that the amplifier meets the requirements of the above standard at the limit of the maximum allowed output power and also with respect to radio ecology.

This master’s thesis is an introduction to the measurement of changes in tissue impedance of blood flow by impedance plethysmography. Other chapters deal with the kinds of plethysmographs and their principles. The aim is to draft four-electrode impedance plethysmograph to measure changes in tissue impedance depending on blood flow. First, describe the individual blocks of the medical instrument. The practical part of the master’s thesis involves circuit design four-electrode plethysmograph. Given that a very important role in its function plays a constant current source operating at a frequency of 60kHz, this subset was implemented and verified its correct function. To draw component schemes used program EAGLE version 5.10.0.

Fiber based ultrashort pulse laser sources are desirable for many applications; however generating high peak powers in fiber lasers is primarily limited by the onset of nonlinear effects such as self-phase modulation, stimulated Raman scattering, and self-focusing. Increasing the fiber core diameter mitigates the onset of these nonlinear effects, but also allows unwanted higher-order transverse spatial modes to propagate. Both large core diameters and single-mode propagation can be simultaneously attained using photonic crystal fibers. Thulium-doped fiber lasers are attractive for high peak power ultrashort pulse systems. They offer a broad gain bandwidth, capable of amplifying sub-100 femtosecond pulses. The longer center wavelength at 2 ?m theoretically enables higher peak powers relative to 1 [micro]m systems since nonlinear effects inversely scale with wavelength. Also, the 2 [micro]m emission is desirable to support applications reaching further into the mid-IR. This work evaluates the performance of a novel all-fiber pump combiner that incorporates a thulium-doped photonic crystal fiber. This fully integrated amplifier is characterized and possesses a large gain bandwidth, essentially single-mode propagation, and high degree of polarization. This innovative all-fiber, thulium-doped photonic crystal fiber amplifier has great potential for enabling high peak powers in 2 [micro]m fiber systems; however the current optical-to-optical efficiency is low relative to similar free-space amplifiers. Further development and device optimization will lead to higher efficiencies and improved performance.