5,473 research outputs found

    Deep generative models for network data synthesis and monitoring

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    Measurement and monitoring are fundamental tasks in all networks, enabling the down-stream management and optimization of the network. Although networks inherently have abundant amounts of monitoring data, its access and effective measurement is another story. The challenges exist in many aspects. First, the inaccessibility of network monitoring data for external users, and it is hard to provide a high-fidelity dataset without leaking commercial sensitive information. Second, it could be very expensive to carry out effective data collection to cover a large-scale network system, considering the size of network growing, i.e., cell number of radio network and the number of flows in the Internet Service Provider (ISP) network. Third, it is difficult to ensure fidelity and efficiency simultaneously in network monitoring, as the available resources in the network element that can be applied to support the measurement function are too limited to implement sophisticated mechanisms. Finally, understanding and explaining the behavior of the network becomes challenging due to its size and complex structure. Various emerging optimization-based solutions (e.g., compressive sensing) or data-driven solutions (e.g. deep learning) have been proposed for the aforementioned challenges. However, the fidelity and efficiency of existing methods cannot yet meet the current network requirements. The contributions made in this thesis significantly advance the state of the art in the domain of network measurement and monitoring techniques. Overall, we leverage cutting-edge machine learning technology, deep generative modeling, throughout the entire thesis. First, we design and realize APPSHOT , an efficient city-scale network traffic sharing with a conditional generative model, which only requires open-source contextual data during inference (e.g., land use information and population distribution). Second, we develop an efficient drive testing system — GENDT, based on generative model, which combines graph neural networks, conditional generation, and quantified model uncertainty to enhance the efficiency of mobile drive testing. Third, we design and implement DISTILGAN, a high-fidelity, efficient, versatile, and real-time network telemetry system with latent GANs and spectral-temporal networks. Finally, we propose SPOTLIGHT , an accurate, explainable, and efficient anomaly detection system of the Open RAN (Radio Access Network) system. The lessons learned through this research are summarized, and interesting topics are discussed for future work in this domain. All proposed solutions have been evaluated with real-world datasets and applied to support different applications in real systems

    Computational Analyses of Metagenomic Data

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    Metagenomics studies the collective microbial genomes extracted from a particular environment without requiring the culturing or isolation of individual genomes, addressing questions revolving around the composition, functionality, and dynamics of microbial communities. The intrinsic complexity of metagenomic data and the diversity of applications call for efficient and accurate computational methods in data handling. In this thesis, I present three primary projects that collectively focus on the computational analysis of metagenomic data, each addressing a distinct topic. In the first project, I designed and implemented an algorithm named Mapbin for reference-free genomic binning of metagenomic assemblies. Binning aims to group a mixture of genomic fragments based on their genome origin. Mapbin enhances binning results by building a multilayer network that combines the initial binning, assembly graph, and read-pairing information from paired-end sequencing data. The network is further partitioned by the community-detection algorithm, Infomap, to yield a new binning result. Mapbin was tested on multiple simulated and real datasets. The results indicated an overall improvement in the common binning quality metrics. The second and third projects are both derived from ImMiGeNe, a collaborative and multidisciplinary study investigating the interplay between gut microbiota, host genetics, and immunity in stem-cell transplantation (SCT) patients. In the second project, I conducted microbiome analyses for the metagenomic data. The workflow included the removal of contaminant reads and multiple taxonomic and functional profiling. The results revealed that the SCT recipients' samples yielded significantly fewer reads with heavy contamination of the host DNA, and their microbiomes displayed evident signs of dysbiosis. Finally, I discussed several inherent challenges posed by extremely low levels of target DNA and high levels of contamination in the recipient samples, which cannot be rectified solely through bioinformatics approaches. The primary goal of the third project is to design a set of primers that can be used to cover bacterial flagellin genes present in the human gut microbiota. Considering the notable diversity of flagellins, I incorporated a method to select representative bacterial flagellin gene sequences, a heuristic approach based on established primer design methods to generate a degenerate primer set, and a selection method to filter genes unlikely to occur in the human gut microbiome. As a result, I successfully curated a reduced yet representative set of primers that would be practical for experimental implementation

    Information actors beyond modernity and coloniality in times of climate change:A comparative design ethnography on the making of monitors for sustainable futures in Curaçao and Amsterdam, between 2019-2022

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    In his dissertation, Mr. Goilo developed a cutting-edge theoretical framework for an Anthropology of Information. This study compares information in the context of modernity in Amsterdam and coloniality in Curaçao through the making process of monitors and develops five ways to understand how information can act towards sustainable futures. The research also discusses how the two contexts, that is modernity and coloniality, have been in informational symbiosis for centuries which is producing negative informational side effects within the age of the Anthropocene. By exploring the modernity-coloniality symbiosis of information, the author explains how scholars, policymakers, and data-analysts can act through historical and structural roots of contemporary global inequities related to the production and distribution of information. Ultimately, the five theses propose conditions towards the collective production of knowledge towards a more sustainable planet

    Non-Market Food Practices Do Things Markets Cannot: Why Vermonters Produce and Distribute Food That\u27s Not For Sale

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    Researchers tend to portray food self-provisioning in high-income societies as a coping mechanism for the poor or a hobby for the well-off. They describe food charity as a regrettable band-aid. Vegetable gardens and neighborly sharing are considered remnants of precapitalist tradition. These are non-market food practices: producing food that is not for sale and distributing food in ways other than selling it. Recent scholarship challenges those standard understandings by showing (i) that non-market food practices remain prevalent in high-income countries, (ii) that people in diverse social groups engage in these practices, and (iii) that they articulate diverse reasons for doing so. In this dissertation, I investigate the persistent pervasiveness of non-market food practices in Vermont. To go beyond explanations that rely on individual motivation, I examine the roles these practices play in society. First, I investigate the prevalence of non-market food practices. Several surveys with large, representative samples reveal that more than half of Vermont households grow, hunt, fish, or gather some of their own food. Respondents estimate that they acquire 14% of the food they consume through non-market means, on average. For reference, commercial local food makes up about the same portion of total consumption. Then, drawing on the words of 94 non-market food practitioners I interviewed, I demonstrate that these practices serve functions that markets cannot. Interviewees attested that non-market distribution is special because it feeds the hungry, strengthens relationships, builds resilience, puts edible-but-unsellable food to use, and aligns with a desired future in which food is not for sale. Hunters, fishers, foragers, scavengers, and homesteaders said that these activities contribute to their long-run food security as a skills-based safety net. Self-provisioning allows them to eat from the landscape despite disruptions to their ability to access market food such as job loss, supply chain problems, or a global pandemic. Additional evidence from vegetable growers suggests that non-market settings liberate production from financial discipline, making space for work that is meaningful, playful, educational, and therapeutic. Non-market food practices mend holes in the social fabric torn by the commodification of everyday life. Finally, I synthesize scholarly critiques of markets as institutions for organizing the production and distribution of food. Markets send food toward money rather than hunger. Producing for market compels farmers to prioritize financial viability over other values such as stewardship. Historically, people rarely if ever sell each other food until external authorities coerce them to do so through taxation, indebtedness, cutting off access to the means of subsistence, or extinguishing non-market institutions. Today, more humans than ever suffer from chronic undernourishment even as the scale of commercial agriculture pushes environmental pressures past critical thresholds of planetary sustainability. This research substantiates that alternatives to markets exist and have the potential to address their shortcomings

    Resource-aware scheduling for 2D/3D multi-/many-core processor-memory systems

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    This dissertation addresses the complexities of 2D/3D multi-/many-core processor-memory systems, focusing on two key areas: enhancing timing predictability in real-time multi-core processors and optimizing performance within thermal constraints. The integration of an increasing number of transistors into compact chip designs, while boosting computational capacity, presents challenges in resource contention and thermal management. The first part of the thesis improves timing predictability. We enhance shared cache interference analysis for set-associative caches, advancing the calculation of Worst-Case Execution Time (WCET). This development enables accurate assessment of cache interference and the effectiveness of partitioned schedulers in real-world scenarios. We introduce TCPS, a novel task and cache-aware partitioned scheduler that optimizes cache partitioning based on task-specific WCET sensitivity, leading to improved schedulability and predictability. Our research explores various cache and scheduling configurations, providing insights into their performance trade-offs. The second part focuses on thermal management in 2D/3D many-core systems. Recognizing the limitations of Dynamic Voltage and Frequency Scaling (DVFS) in S-NUCA many-core processors, we propose synchronous thread migrations as a thermal management strategy. This approach culminates in the HotPotato scheduler, which balances performance and thermal safety. We also introduce 3D-TTP, a transient temperature-aware power budgeting strategy for 3D-stacked systems, reducing the need for Dynamic Thermal Management (DTM) activation. Finally, we present 3QUTM, a novel method for 3D-stacked systems that combines core DVFS and memory bank Low Power Modes with a learning algorithm, optimizing response times within thermal limits. This research contributes significantly to enhancing performance and thermal management in advanced processor-memory systems

    Choreographing tragedy into the twenty-first century

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    What makes a tragedy? In the fifth century BCE this question found an answer through the conjoined forms of song and dance. Since the mid-twentieth century, and the work of the Tanztheater Wuppertal Pina Bausch, tragedy has been variously articulated as form coming apart at the seams. This thesis approaches tragedy through the work of five major choreographers and a director who each, in some way, turn back to Bausch. After exploring the Tanztheater Wuppertal’s techniques for choreographing tragedy in chapter one, I dedicate a chapter each to Dimitris Papaioannou, Akram Khan, Trajal Harrell, Ivo van Hove with Wim Vandekeybus, and Gisèle Vienne. Bringing together work in Queer and Trans* studies, Performance studies, Classics, Dance, and Classical Reception studies I work towards an understanding of the ways in which these choreographers articulate tragedy through embodiment and relation. I consider how tragedy transforms into the twenty-first century, how it shapes what it might mean to live and die with(out) one another. This includes tragic acts of mythic construction, attempts to describe a sense of the world as it collapses, colonial claims to ownership over the earth, and decolonial moves to enact new ways of being human. By developing an expanded sense of both choreography and the tragic one of my main contributions is a re-theorisation of tragedy that brings together two major pre-existing schools, to understand tragedy not as an event, but as a process. Under these conditions, and the shifting conditions of the world around us, I argue that the choreography of tragedy has and might continue to allow us to think about, name, and embody ourselves outside of the ongoing catastrophes we face

    A Critical Review Of Post-Secondary Education Writing During A 21st Century Education Revolution

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    Educational materials are effective instruments which provide information and report new discoveries uncovered by researchers in specific areas of academia. Higher education, like other education institutions, rely on instructional materials to inform its practice of educating adult learners. In post-secondary education, developmental English programs are tasked with meeting the needs of dynamic populations, thus there is a continuous need for research in this area to support its changing landscape. However, the majority of scholarly thought in this area centers on K-12 reading and writing. This paucity presents a phenomenon to the post-secondary community. This research study uses a qualitative content analysis to examine peer-reviewed journals from 2003-2017, developmental online websites, and a government issued document directed toward reforming post-secondary developmental education programs. These highly relevant sources aid educators in discovering informational support to apply best practices for student success. Developmental education serves the purpose of addressing literacy gaps for students transitioning to college-level work. The findings here illuminate the dearth of material offered to developmental educators. This study suggests the field of literacy research is fragmented and highlights an apparent blind spot in scholarly literature with regard to English writing instruction. This poses a quandary for post-secondary literacy researchers in the 21st century and establishes the necessity for the literacy research community to commit future scholarship toward equipping college educators teaching writing instruction to underprepared adult learners

    Auditable and performant Byzantine consensus for permissioned ledgers

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    Permissioned ledgers allow users to execute transactions against a data store, and retain proof of their execution in a replicated ledger. Each replica verifies the transactions’ execution and ensures that, in perpetuity, a committed transaction cannot be removed from the ledger. Unfortunately, this is not guaranteed by today’s permissioned ledgers, which can be re-written if an arbitrary number of replicas collude. In addition, the transaction throughput of permissioned ledgers is low, hampering real-world deployments, by not taking advantage of multi-core CPUs and hardware accelerators. This thesis explores how permissioned ledgers and their consensus protocols can be made auditable in perpetuity; even when all replicas collude and re-write the ledger. It also addresses how Byzantine consensus protocols can be changed to increase the execution throughput of complex transactions. This thesis makes the following contributions: 1. Always auditable Byzantine consensus protocols. We present a permissioned ledger system that can assign blame to individual replicas regardless of how many of them misbehave. This is achieved by signing and storing consensus protocol messages in the ledger and providing clients with signed, universally-verifiable receipts. 2. Performant transaction execution with hardware accelerators. Next, we describe a cloud-based ML inference service that provides strong integrity guarantees, while staying compatible with current inference APIs. We change the Byzantine consensus protocol to execute machine learning (ML) inference computation on GPUs to optimize throughput and latency of ML inference computation. 3. Parallel transactions execution on multi-core CPUs. Finally, we introduce a permissioned ledger that executes transactions, in parallel, on multi-core CPUs. We separate the execution of transactions between the primary and secondary replicas. The primary replica executes transactions on multiple CPU cores and creates a dependency graph of the transactions that the backup replicas utilize to execute transactions in parallel.Open Acces

    To make the dominoes fall: A relational-processual approach to societal accountability in the Italian and Spanish anti-corruption arenas

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    In che modo le organizzazioni della società civile (OSC) contribuiscono alla lotta contro la corruzione? Come possono responsabilizzare i rappresentanti politici? La presente tesi si propone di rispondere a queste a queste domande di ricerca, unendo gli studi sulla lotta alla corruzione a quelli sui movimenti sociali e concentrandosi sul concetto di societal accountability, cioè sui meccanismi di controllo e di sanzione dei rappresentanti pubblici. Negli ultimi anni, gli studiosi della corruzione hanno enfatizzato sempre più il ruolo della società civile come antidoto contro la corruzione, a complemento dei meccanismi di accountability statali ed elettorali. Tuttavia, gli studi empirici sugli effetti anticorruzione degli interventi civici non hanno ancora prodotto risultati coerenti. Questo non dovrebbe sorprendere. Se misurare la corruzione è un compito arduo, valutare se e quanto gli scambi corruttivi vengano impediti grazie alle iniziative della società civile sembra virtualmente impossibile. Per questo motivo, il presente lavoro fa un passo indietro e problematizza lo studio della societal accountability, affrontandola non come un insieme predefinito di meccanismi o pratiche messe in atto da attori civici anticorruzione, ma come il risultato di interazioni sostenute e conflittuali tra più attori, civici e non. Per fare ciò, lo studio si ispira alle teorie dei movimenti sociali e concettualizza la societal accountability come un insieme di conseguenze dell’azione collettiva. Pertanto, questo lavoro mira a capire come e in quali condizioni le iniziative anticorruzione dal basso raggiungano risultati di accountability, quali il passaggio di nuove norme, il miglioramento dell’answerability istituzionale e potenziale sanzionatorio. Con questo obiettivo, la tesi si basa sulle evidenze esistenti negli studi sulla corruzione e sull'accountability e contribuisce ai dibattiti in corso sulle conseguenze dell'azione collettiva. Il quadro teorico si concentra sul concetto di influenza, aderendo a un approccio processuale-relazionale. L'influenza è intesa come un'istanza di causalità relazionale, una forma di potere posizionale che consente a più attori di esercitare un controllo sulle conseguenze dell’azione collettiva. Facendo da ponte tra l'approccio strategico-interazionale e i modelli di mediazione, l'analisi chiarisce le strategie seguite dalle OSC nella ricerca di posizioni di influenza, così come i meccanismi attraverso i quali i modelli relazionali producono cambiamento sociale. Il quadro analitico è applicato alle arene anticorruzione in Italia e in Spagna e si restringe a tre specifiche aree di intervento: l'introduzione di leggi sulla trasparenza, l'approvazione di leggi per la protezione dei whistleblower e lo sviluppo di progetti di monitoraggio civico. Il materiale empirico comprende 37 interviste qualitative semi-strutturate, documenti e dati network. Nel complesso, le evidenze raccolte contribuiscono alla letteratura sulla lotta alla corruzione, dimostrando che le OSC contribuiscono, direttamente e indirettamente, alla lotta contro la corruzione ottenendo cambiamenti nelle politiche, aumentando l’answerability del sistema e innescando sanzioni formali e informali quando necessario. Tuttavia, l’analisi comparata dei casi italiano e spagnolo evidenziano differenze rilevanti. In particolare, l'indagine empirica contribuisce agli attuali dibattiti sullo studio della società della social accountability, dimostrando che l'integrazione con le élite politiche può aumentare la probabilità di ottenere di ottenere un cambiamento delle politiche, mentre l'integrazione orizzontale tra gli attori civici può aumentare il loro potenziale sanzionatorio. In definitiva, questo lavoro dimostra come gli approcci processuali-relazionali possano integrare modelli strategici e di mediazione per comprendere meglio il modo in cui gli attori collettivi influenzano il cambiamento politico e sociale. Le osservazioni conclusive sostengono che le interazioni e le relazioni costruite dagli attori nel corso del tempo e in diverse arene fungono da canali di mediazione a livello micro, meso e macro. Complessivamente, ciò dimostra che i singoli attori, i modelli di relazione nelle e tra le arene e le idee sulle relazioni mediano tra le strategie dei attori collettivi, aumentando o limitando così la loro influenza sulla lotta alla corruzione.How do civil society organizations (CSOs) contribute to the struggle against public corruption? How can they hold their political representatives accountable? This thesis aims to answer these wide-ranging research questions, bridging anti-corruption and social movement studies by focusing on societal accountability, i.e., grassroots mechanisms for controlling and sanctioning powerholders. Over the last few years, corruption scholars have increasingly emphasized the role of civil society as an antidote against corruption, complementing state and electoral accountability mechanisms. However, empirical studies on the anti-corruption effects of civic interventions have yet to yield consistent results. This should hardly come as a surprise. If measuring corruption is a challenging task, assessing the extent to which corrupt deals are prevented due to civil society initiatives appears virtually impossible. Hence, this work takes a step back and problematizes the study of societal accountability, approaching it not as a pre-given set of mechanisms or practices deployed by anti-corruption civic actors but as the result of sustained and contentious interactions between multiple players. To do so, the study draws on social movement theories and conceptualizes societal accountability as a set of consequences of collective action efforts. Therefore, this work aims to understand how and under what conditions bottom-up anti-corruption initiatives achieve accountability results such as legal claim attainments, answerability, and sanctioning potential. With this goal in mind, the thesis builds upon existing evidence from corruption and accountability studies and contributes to ongoing debates on the consequences of collective action. The theoretical framework focuses on the concept of influence, subscribing to a processual-relational approach. It understands influence as a relationally emergent instance of causality, a form of positional power that enables multiple players to exert control over the consequences of collective struggles. By bridging the strategic-interaction approach and mediation models; the analysis elucidates the strategies followed by CSOs in seeking positions of influence, as well as the mechanisms through which relational patterns produce social change. The analytical framework is applied to the anti-corruption arenas in Italy and Spain and is narrowed down by focusing on three specific campaigns in each country: introducing transparency laws, passing whistleblowers' protection acts, and developing civic monitoring projects. The empirical material comprises 37 semi-structured qualitative interviews, documents, and network data retrieved through Action Organization Analysis. The corpus of data is analyzed by combining thematic analysis, frame analysis, and a theory-building process tracing through a qualitative network approach. Overall, the evidence collected contributes to the literature on anti-corruption, demonstrating that CSOs, directly and indirectly, contribute to the anti-corruption struggle by achieving policy change, increasing the system's answerability, and triggering formal and informal sanctions when necessary. However, the Italian and Spanish cases' comparative accounts highlight relevant differences. In particular, the empirical investigation contributes to current debates on the study of societal accountability, showing that integration with political elites may increase the likelihood of obtaining policy change, whereas horizontal integration among civic actors may enhance their sanctioning potential. Ultimately, this work shows how processual-relational approaches can help integrate strategic and mediation models to understand better how change-oriented collective actors influence political and social change. The concluding remarks maintain that the interactions and relations built by players over time and across different arenas serve as mediation channels at the micro-, meso-, and macro-levels. Overall, this demonstrates that individual players, patterns of relations in and across arenas, and ideas about relationships mediate between players' strategies, resources, or frames and their contextual conditions, thereby increasing or constraining their influence over the anti-corruption struggl
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