Design of Wireless Communication Networks for Cyber-Physical Systems with Application to Smart Grid

Cyber-Physical Systems (CPS) are the next generation of engineered systems in which computing, communication, and control technologies are tightly integrated. On one hand, CPS are generally large with components spatially distributed in physical world that has lots of dynamics; on the other hand, CPS are connected, and must be robust and responsive. Smart electric grid, smart transportation system are examples of emerging CPS that have significant and far-reaching impact on our daily life. In this dissertation, we design wireless communication system for CPS. To make CPS robust and responsive, it is critical to have a communication subsystem that is reliable, adaptive, and scalable. Our design uses a layered structure, which includes physical layer, multiple access layer, network layer, and application layer. Emphases are placed on multiple access and network layer. At multiple access layer, we have designed three approaches, namely compressed multiple access, sample-contention multiple access, and prioritized multiple access, for reliable and selective multiple access. At network layer, we focus on the problem of creating reliable route, with service interruption anticipated. We propose two methods: the first method is a centralized one that creates backup path around zones posing high interruption risk; the other method is a distributed one that utilizes Ant Colony Optimization (ACO) and positive feedback, and is able to update multipath dynamically. Applications are treated as subscribers to the data service provided by the communication system. Their data quality requirements and Quality of Service (QoS) feedback are incorporated into cross-layer optimization in our design. We have evaluated our design through both simulation and testbed. Our design demonstrates desired reliability, scalability and timeliness in data transmission. Performance gain is observed over conventional approaches as such random access

Values education through media education in EFL classroom in forms 8-9

Käesoleva magistritöö eesmärgiks on uurida võimalusi põhikooli riikliku õppekava nõuete järgimiseks inglise keele kui võõrkeele tunnis ning luua tunnikava, mis keskenduks õppekavas esitatud läbivatele teemadele ja üldpädevustele. Tunnikava keskendub meediakasvatusele ja väärtuskasvatusele ning nende võimalikule kombineerimisele inglise keele õppega. Töö koosneb sissejuhatusest, kahest peatükist ja kokkuvõttest. Töö sissejuhatuses antakse lühiülevaade riikliku õppekava nõuetest ja meediakasvatuse ja väärtuskasvatuse rollist õppekavas. Sissejuhatuses tutvustatakse ka tunnikava koostamise põhjuseid. Töö teoreetilises osas käsitletakse laiemalt õppekava läbivaid teemasid ning üldpädevusi. Lisaks sellele keskendub teoreetiline peatükk põhjalikumalt ka meediakasvatuse ja väärtuskasvatuse rollile ja taustale. Töö empiiriline osa kätkeb endas põhimõtteid, mida kasutati tunnikava loomisel. Peale selle tegeleb empiiriline osa ka sihtrühma õpilaste tutvustamisele, kellele tunnikava läbi õpetati ning tunnikava ja katse-õpetamise analüüs. Tunnikava analüüs näitas, et õpilased ei suutnud võrdselt tähelepanu pöörata kõigile kolmele tunnikava aspektile: meediakasvatusele, väärtuskasvatusele ja inglise keelele. Kõige paremad tulemused saavutati inglise keele tasemel, mis oli ka ainuke konkreetselt hinnatav tunnikava aspekt. Meediakasvatuse ja väärtuskasvatuse aspektide eest õpilased hindeid ei saanud, sest antud tunnikava läbiõpetamise periood oli liialt lühike järelduste tegemiseks, kuna riiklik õppekava näeb ette, et õppekava läbivaid teemasid ja üldpädevusi arendatakse kogu põhikooliõppe kestel

Unmute This: Circulation, Sociality, and Sound in Viral Media

Cats at keyboards. Dancing hamsters. Giggling babies and dancing flashmobs. A bi-colored dress. Psy’s “Gangnam Style” music video. Over the final decade of the twentieth century and the first decades of the twenty-first, these and countless other examples of digital audiovisual phenomena have been collectively adjectivally described through a biological metaphor that suggests the speed and ubiquity of their circulation—“viral.” This circulation has been facilitated by the internet, and has often been understood as a product of the web’s celebrated capacities for democratic amateur creation, its facilitation of unmediated connection and sharing practices. In this dissertation, I suggest that participation in such phenomena—the production, watching, listening to, circulation, or “sharing” of such objects—has constituted a significant site of twenty-first-century musical practice. Borrowing and adapting Christopher Small’s influential 1998 coinage, I theorize these strands of practice as viral musicking. While scholarship on viral media has tended to center on visual parameters, rendering such phenomena silent, the term “viral musicking” seeks to draw media theory metaphors of voice and listening into dialogue with musicology, precisely at the intersection of audiovisual objects which are played, heard, listened to. The project’s methodology comprises a sonically attuned media archeology, grounded in close readings of internet artifacts and practices; this sonic attunement is afforded through musicological methods, including analyses of genre, aesthetics, and style, discourse analysis, and twenty-first-century reception (micro)histories across a dynamic media assemblage. By analyzing particular ecosystems of platforms, behavior, and devices across the first decades of the twenty-first century, I chart a trajectory in which unpredictable virtual landscapes were tamed into entrenched channels and pathways, enabling a capacious “virality” comprising disparate phenomena from simple looping animations to the surprise release of Beyoncé’s 2013 album. Alongside this narrative, I challenge utopian claims of Web 2.0’s digital democratization by explicating the iterative processes through which material, work, and labor were co-opted from amateur content creators and leveraged for the profit of established media and corporate entities. “Unmute This” articulates two main arguments. First, that virality reified as a concept and set of dynamic-but-predictable processes over the course of the first decades of the twenty-first century; this dissertation charts a cartography of chaos to control, a heterogeneous digital landscape funneled into predictable channels and pathways etched ever more firmly and deeply across the 2010s. Second, that analyzing the musicality of viral objects, attending to the musical and sonic parameters of virally-circulating phenomena, and thinking of viral participation as an extension of musical behavior provide a productive framework for understanding the affective, generic, and social aspects of twenty-first-century virality. The five chapters of the dissertation present analyses of a series of viral objects, arranged roughly chronologically from the turn of the twenty-first century to the middle of the 2010s. The first chapter examines the loops of animated phenomena from The Dancing Baby to Hampster Dance and the Badgers animation; the second moves from loops to musicalization, considering remixing approaches to the so-called “Bus Uncle” and “Bed Intruder” videos. The third chapter also deals with viral remixing, centering around Rebecca Black’s “Friday” video, while the fourth chapter analyzes “unmute this” video posts in the context of the mid-2010s social media platform assemblage. The final chapter presents the 2013 surprise release of Beyoncé’s self-titled visual album as an apotheosis to the viral narratives that precede it—a claim that is briefly interrogated in the dissertation’s epilogue

uTango: an open-source TEE for IoT devices

Security is one of the main challenges of the Internet of Things (IoT). IoT devices are mainly powered by low-cost microcontrollers (MCUs) that typically lack basic hardware security mechanisms to separate security-critical applications from less critical components. Recently, Arm has started to release Cortex-M MCUs enhanced with TrustZone technology (i.e., TrustZone-M), a system-wide security solution aiming at providing robust protection for IoT devices. Trusted Execution Environments (TEEs) relying on TrustZone hardware have been perceived as safe havens for securing mobile devices. However, for the past few years, considerable effort has gone into unveiling hundreds of vulnerabilities and proposing a collection of relevant defense techniques to address several issues. While new TEE solutions built on TrustZone-M start flourishing, the lessons gathered from the research community appear to be falling short, as these new systems are trapping into the same pitfalls of the past. In this paper, we present UTANGO, the first multi-world TEE for modern IoT devices. UTANGO proposes a novel architecture aiming at tackling the major architectural deficiencies currently affecting TrustZone(-M)-assisted TEEs. In particular, we leverage the very same TrustZone hardware primitives used by dual-world implementations to create multiple and equally secure execution environments within the normal world. We demonstrate the benefits of UTANGO by conducting an extensive evaluation on a real TrustZone-M hardware platform, i.e., Arm Musca-B1. UTANGO will be open-sourced and freely available on GitHub in hopes of engaging academia and industry on securing the foreseeable trillion IoT devices.This work was supported in part by the Fundacao para a Ciencia e Tecnologia (FCT) within the Research and Development Units under Grant UIDB/00319/2020, and in part by FCT within the Ph.D. Scholarship under Grant 2020.04585.BD

CME for Family Mediators

Meeting proceedings of a seminar by the same name, held August 19, 2022

PUBLIC BLOCKCHAIN SCALABILITY: ADVANCEMENTS, CHALLENGES AND THE FUTURE

In the last decade, blockchain has emerged as one of the most influential innovations in software architecture and technology. Ideally, blockchains are designed to be architecturally and politically decentralized, similar to the Internet. But recently, public and permissionless blockchains such as Bitcoin and Ethereum have faced stumbling blocks in the form of scalability. Both Bitcoin and Ethereum process fewer than 20 transactions per second, which is significantly lower than their centralized counterpart such as VISA that can process approximately 1,700 transactions per second. In realizing this hindrance in the wide range adoption of blockchains for building advanced and large scalable systems, the blockchain community has proposed first- and second-layer scaling solutions including Segregated Witness (Segwit), Sharding, and two-way pegged sidechains. Although these proposals are innovative, they still suffer from the blockchain trilemma of scalability, security, and decentralization. Moreover, at this time, little is known or discussed regarding factors related to design choices, feasibility, limitations and other issues in adopting the various first- and second-layer scaling solutions in public and permissionless blockchains. Hence, this thesis provides the first comprehensive review of the state-of-the-art first- and second-layer scaling solutions for public and permissionless blockchains, identifying current advancements and analyzing their impact from various viewpoints, highlighting their limitations and discussing possible remedies for the overall improvement of the blockchain domain

Apropos Obsolescence

Apropos Obsolescence is the title of this PhD in visual art dissertation and exhibition. It is an exploration of how a human mind interfaces with and mediates both proximal space and the larger environment of planet Earth. How is the outside brought inside? What is mediation and how does it operate upon our consciousness? Within the exhibition explored in this text are several works that investigate mediation. The main work, Hexagraphy, is a rudimentary backlit screen; a sculpture that refers to a field of neurons using light. Neurons in the brains hippocampus region are active during movement as a component of our agency in connecting to the navigational aspect of consciousness. These neurons operating in grids are calculating our direction and placement in space as we move around. To engage with this information, I improvised a decentered geometry for some of the work in the exhibition. In other works, I included signs of the enormous physical forces that are in play on the planet, the non-local phased objects we are immersed within that are not easily represented due to their enormity, but that technoscience exposes. Two questions became evident to me through looking at both science and new materialist philosophy. The first is that following the digital turn, an extension of our senses aided by computation, it is clear that humanity exists contingently on planet Earth. Humanity was not the beginning and is not the end of evolution. Thus, upending any notion that any thing was created for us. Secondly, is technology as an end in itself helpful for humanity? Through its decentering of humanity and imposing an acknowledgement of contingency upon us, the entire realm of objects is paradoxically elevated. This decentering could be the only thing that saves our species from extinction. It may be the objects that save us. Hyperobjects like hurricanes and El Nino, or climate change in general are caused by a combination of cyclical forces. These large objects decenter humanity, and in my artwork, I want to emphasize the fact that I am a fragile human and not a machine

Parallel Programming with Global Asynchronous Memory: Models, C++ APIs and Implementations

In the realm of High Performance Computing (HPC), message passing has been the programming paradigm of choice for over twenty years. The durable MPI (Message Passing Interface) standard, with send/receive communication, broadcast, gather/scatter, and reduction collectives is still used to construct parallel programs where each communication is orchestrated by the developer-based precise knowledge of data distribution and overheads; collective communications simplify the orchestration but might induce excessive synchronization. Early attempts to bring shared-memory programming model—with its programming advantages—to distributed computing, referred as the Distributed Shared Memory (DSM) model, faded away; one of the main issue was to combine performance and programmability with the memory consistency model. The recently proposed Partitioned Global Address Space (PGAS) model is a modern revamp of DSM that exposes data placement to enable optimizations based on locality, but it still addresses (simple) data- parallelism only and it relies on expensive sharing protocols. We advocate an alternative programming model for distributed computing based on a Global Asynchronous Memory (GAM), aiming to avoid coherency and consistency problems rather than solving them. We materialize GAM by designing and implementing a distributed smart pointers library, inspired by C++ smart pointers. In this model, public and pri- vate pointers (resembling C++ shared and unique pointers, respectively) are moved around instead of messages (i.e., data), thus alleviating the user from the burden of minimizing transfers. On top of smart pointers, we propose a high-level C++ template library for writing applications in terms of dataflow-like networks, namely GAM nets, consisting of stateful processors exchanging pointers in fully asynchronous fashion. We demonstrate the validity of the proposed approach, from the expressiveness perspective, by showing how GAM nets can be exploited to implement both standalone applications and higher-level parallel program- ming models, such as data and task parallelism. As for the performance perspective, preliminary experiments show both close-to-ideal scalability and negligible overhead with respect to state-of-the-art benchmark implementations. For instance, the GAM implementation of a high-quality video restoration filter sustains a 100 fps throughput over 70%-noisy high-quality video streams on a 4-node cluster of Graphics Processing Units (GPUs), with minimal programming effort