Blockchain Software Verification and Optimization

In the last decade, blockchain technology has undergone a strong evolution. The maturity reached and the consolidation obtained have aroused the interest of companies and businesses, transforming it into a possible response to various industrial needs. However, the lack of standards and tools for the development and maintenance of blockchain software leaves open challenges and various possibilities for improvements. The goal of this thesis is to tackle some of the challenges proposed by blockchain technology, to design and implement analysis, processes, and architectures that may be applied in the real world. In particular, two topics are addressed: the verification of the blockchain software and the code optimization of smart contracts. As regards the verification, the thesis focuses on the original developments of tools and analyses able to detect statically, i.e. without code execution, issues related to non-determinism, untrusted cross-contracts invocation, and numerical overflow/underflow. Moreover, an approach based on on-chain verification is investigated, to proactively involve the blockchain in verifying the code before and after its deployment. For the optimization side, the thesis describes an optimization process for the code translation from Solidity language to Takamaka, also proposing an efficient algorithm to compute snapshots for fungible and non-fungible tokens. The results of this thesis are an important first step towards improving blockchain software development, empirically demonstrating the applicability of the proposed approaches and their involvement also in the industrial field

Model Identification, Updating, and Validation of an Active Magnetic Bearing High-Speed Machining Spindle for Precision Machining Operation

High-Speed Machining (HSM) spindles equipped with Active Magnetic Bearings (AMBs) are envisioned to be capable of autonomous self-identification and performance self-optimization for stable high-speed and high quality machining operation. High-speed machining requires carefully selected parameters for reliable and optimal machining performance. For this reason, the accuracy of the spindle model in terms of physical and dynamic properties is essential to substantiate confidence in its predictive aptitude for subsequent analyses.This dissertation addresses system identification, open-loop model development and updating, and closed-loop model validation. System identification was performed in situ utilizing the existing AMB hardware. A simplified, nominal open-loop rotor model was developed based on available geometrical and material information. The nominal rotor model demonstrated poor correlation when compared with open-loop system identification data. Since considerable model error was realized, the nominal rotor model was corrected by employing optimization methodology to minimize the error of resonance and antiresonance frequencies between the modeled and experimental data.Validity of the updated open-loop model was demonstrated through successful implementation of a MIMO u-controller. Since the u-controller is generated based on the spindle model, robust levitation of the real machining spindle is achieved only when the model is of high fidelity. Spindle performance characterization was carried out at the tool location through evaluations of the dynamic stiffness as well as orbits at various rotational speeds. Updated model simulations exhibited high fidelity correspondence to experimental data confirming the predictive aptitude of the updated model. Further, a case study is presented which illustrates the improved performance of the u-controller when designed with lower uncertainty of the model\u27s accurac

Simveillance in hyperreal Las Vegas

On a Thursday afternoon, an average Canadian leaves her office, and goes to a nearby bank machine to get a cash advance on one of her credit cards. She uses the money to buy lunch at a mall food court, then wanders into various shops purchasing clothing and compact discs with her Interac-equipped bank card. Returning to her office, she logs on to the internet, and checks her email. She then goes back to her assigned task of data entry. An ordinary day for millions of Canadians, but what is extraordinary is how well-documented this banal trip was. The woman’s face has been photographed, videotaped, and time-coded. Records of her purchases have been distributed to her, the stores, and her bank. Her employer knows that she has checked her email. Were she to go missing, investigators would be able to put together a fairly comprehensive itinerary of her day, and there would be plenty of up-to-date images for the evening news. But it should be noted, It is possible that at no time during her day was she actually being watched by a pair of human eyes. It is not an overstatement to claim that surveillance permeates many aspects of North American life. There is no shortage of sociological theory to help illuminate the situation; sociologists have been keenly aware of the importance of surveillance for decades. However, at the dawn of the 21®' century, it is questionable whether the theories that have dominated surveillance discourse for the last twenty-five years can still provide insight. Technology has certainly advanced in that time, both in capability and in frequency. The average person now takes for granted technology that would have been unthinkable a quarter of a century ago. Along with the technological envelopment has come an immersion in simulation, as people find themselves operating in a virtual world of computers and videoscreens. The question is whether this has simply intensified conventional surveillance in North American society, or produced a new kind of creature entirely. This thesis will argue that the articulation of the two forces has produced a hybrid; for lack of a better word, this hybrid can be called simveillance. Simveillance can not be encompassed by the classic concepts of surveillance that dominate current discourse

MSFC Skylab structures and mechanical systems mission evaluation

A performance analysis for structural and mechanical major hardware systems and components is presented. Development background testing, modifications, and requirement adjustments are included. Functional narratives are provided for comparison purposes as are predicted design performance criterion. Each item is evaluated on an individual basis: that is, (1) history (requirements, design, manufacture, and test); (2) in-orbit performance (description and analysis); and (3) conclusions and recommendations regarding future space hardware application. Overall, the structural and mechanical performance of the Skylab hardware was outstanding

A Problem-Oriented Approach for Dynamic Verification of Heterogeneous Embedded Systems

This work presents a virtual prototyping methodology for the design and verification of industrial devices in the field level of industrial automation systems. This work demonstrates that virtual prototypes can help increase the confidence in the correctness of a design thanks to a deeper understanding of the complex interactions between hardware, software, analog and mixed-signal components of embedded systems and the physical processes they interact with