315 research outputs found
Fault tolerant data management system
Described in detail are: (1) results obtained in modifying the onboard data management system software to a multiprocessor fault tolerant system; (2) a functional description of the prototype buffer I/O units; (3) description of modification to the ACADC and stimuli generating unit of the DTS; and (4) summaries and conclusions on techniques implemented in the rack and prototype buffers. Also documented is the work done in investigating techniques of high speed (5 Mbps) digital data transmission in the data bus environment. The application considered is a multiport data bus operating with the following constraints: no preferred stations; random bus access by all stations; all stations equally likely to source or sink data; no limit to the number of stations along the bus; no branching of the bus; and no restriction on station placement along the bus
Quantum-based security in optical fibre networks
Electronic communication is used everyday for a number of different applications.
Some of the information transferred during these communications can be private
requiring encryption and authentication protocols to keep this information secure.
Although there are protocols today which provide some security, they are not
necessarily unconditionally secure. Quantum based protocols on the other hand, can
provide unconditionally secure protocols for encryption and authentication.
Prior to this Thesis, only one experimental realisation of quantum digital signatures had
been demonstrated. This used a lossy photonic device along with a quantum memory
allowing two parties to test whether they were sent the same signature by a single
sender, and also store the quantum states for measurement later. This restricted the
demonstration to distances of only a few metres, and was tested with a primitive
approximation of a quantum memory rather than an actual one. This Thesis presents an
experimental realisation of a quantum digital signature protocol which removes the
reliance on quantum memory at the receivers, making a major step towards practicality.
By removing the quantum memory, it was also possible to perform the swap and
comparison mechanism in a more efficient manner resulting in an experimental
realisation of quantum digital signatures over 2 kilometres of optical fibre.
Quantum communication protocols can be unconditionally secure, however the
transmission distance is limited by loss in quantum channels. To overcome this loss in
conventional channels an optical amplifier is used, however the added noise from these
would swamp the quantum signal if directly used in quantum communications.
This Thesis looked into probabilistic quantum amplification, with an experimental
realisation of the state comparison amplifier, based on linear optical components and
single-photon detectors. The state comparison amplifier operated by using the wellestablished
techniques of optical coherent state comparison and weak subtraction to
post-select the output and provide non-deterministic amplification with increased
fidelity at a high repetition rate. The success rates of this amplifier were found to be
orders of magnitude greater than other state of the art quantum amplifiers, due to its lack
of requirement for complex quantum resources, such as single or entangled photon
sources, and photon number resolving detectors
Modeling and Simulation of Nonlinearly Loaded Electromagnetic Systems via Reduced Order Models - A Case Study: Energy Selective Surfaces
L'abstract è presente nell'allegato / the abstract is in the attachmen
Ideal quantum protocols in the non-ideal physical world
The development of quantum protocols from conception to experimental realizations is one of
the main sources of the stimulating exchange between fundamental and experimental research
characteristic to quantum information processing. In this thesis we contribute to the development
of two recent quantum protocols, Universal Blind Quantum Computation (UBQC) and Quantum
Digital Signatures (QDS). UBQC allows a client to delegate a quantum computation to a more
powerful quantum server while keeping the input and computation private. We analyse the resilience
of the privacy of UBQC under imperfections. Then, we introduce approximate blindness
quantifying any compromise to privacy, and propose a protocol which enables arbitrary levels of
security despite imperfections. Subsequently, we investigate the adaptability of UBQC to alternative
implementations with practical advantages. QDS allow a party to send a message to other
parties which cannot be forged, modified or repudiated. We analyse the security properties of a
first proof-of-principle experiment of QDS, implemented in an optical system. We estimate the
security failure probabilities of our system as a function of protocol parameters, under all but the
most general types of attacks. Additionally, we develop new techniques for analysing transformations
between symmetric sets of states, utilized not only in the security proofs of QDS but in
other applications as well
Single Event Effects in FPGA Devices 2015-2016
This presentation provides an overview of single event effects in FPGA devices 2015-2016 including commercial Xilinx V5 heavy ion accelerated testing, Xilinx Kintex-7 heavy ion accelerated testing. Mitigation study, and investigation of various types of triple modular redundancy (TMR) for commercial SRAM based FPGAs
Problems related to the integration of fault tolerant aircraft electronic systems
Problems related to the design of the hardware for an integrated aircraft electronic system are considered. Taxonomies of concurrent systems are reviewed and a new taxonomy is proposed. An informal methodology intended to identify feasible regions of the taxonomic design space is described. Specific tools are recommended for use in the methodology. Based on the methodology, a preliminary strawman integrated fault tolerant aircraft electronic system is proposed. Next, problems related to the programming and control of inegrated aircraft electronic systems are discussed. Issues of system resource management, including the scheduling and allocation of real time periodic tasks in a multiprocessor environment, are treated in detail. The role of software design in integrated fault tolerant aircraft electronic systems is discussed. Conclusions and recommendations for further work are included
Online monitoring system using reactor and mass spectrometry
The combination of micro reactor and analytical devices are popular in research and industry, in addition to the automation of analytical tasks. An automated system for online reaction monitoring in a micro reactor using a mass spectrometer has therefore been realized. The system offers fast data acquisition at discrete time-point in a reaction process. In addition, different functions and utilities that facilitate the convenience to users are included: A dilution module, integration of the micro reactor system to an ICP-MS, two sampling methods, a heating module and a control software
Intelligent Controller Based on Artificial Neural Network and INC Based MPPT for Grid Integrated Solar PV System
Solar photovoltaic (PV) systems have become an integral part of today's advanced energy infrastructure due to its low kinetic energy, its abundance availability, and its freedom from human interference. Solar PV systems have the potential to greatly reduce our reliance on fossil fuels, but their intermittent nature means they cannot provide a constant source of electricity. The system's security should be well thought out, and it should be able to withstand a lot of abuse. The current energy system faces a significant difficulty in ensuring continuous supply. In this study, a three-phase, two-stage photovoltaic system that is managed by artificial neural networks (ANN). A DC-DC boost converter with maximum power point tracking (MPPT) based on the incremental conductance (INC) method is incorporated in the first stage. In the next step, an ANN-based controller optimizes the performance of a three-phase switching PWM inverter that is connected to the grid by controlling currents along the d-q axis. Comprehensive simulations were carried out using MATLAB or Simulink to evaluate the system's performance under various illumination and temperature conditions. Results show that the suggested approach outperforms the baseline in a number of areas. Better dynamic reactions, accurate tracking of reference currents within permissible bounds, and quick settling periods after startup are all displayed by it. These findings show that our method has the potential to greatly improve the efficiency and dependability of solar PV systems. The results of this study have implications for renewable energy in general and present a viable path toward enhancing the resilience and sustainability of energy infrastructure
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