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A Cost-effective Framework to Proactive and Non-disruptive Attack Mitigation in Kubernetes Clusters
Get PDFA large-scale cluster of containers managed with an orchestrator like Kubernetes is behind many cloud-native applications today. However, the weaker isolation provided by containers means attackers can potentially exploit a vulnerable container and then escape its isolation to cause more severe damage to the underlying infrastructure and its hosted applications. Besides, Kubernetes reportedly suffers from security vulnerabilities and misconfigurations which may lead to severe security threats.
Defending against such an attack using existing attack detection solutions can be challenging. Due to the well-known high false positive rate of such solutions, taking aggressive actions upon every alert can lead to unacceptable service disruption. On the other hand, waiting for security administrators to perform in-depth analysis and validation could render the mitigation too late to prevent irreversible damages, e.g., denial of service. In this thesis, we propose WARP, a cost-effective framework to proactive and non-disruptive attack mitigation to address such security challenges for Kubernetes clusters. First, our framework is proactive in the sense that it performs mitigation based on predicted (instead of real) attacks, which prevents irreversible damages. Second, our mitigation framework is designed to be non-disruptive and it is achieved through live migration of containers, which causes no service disruption even in the case of false positives. Finally, to realize the full potential of this framework in containers migration, we formulate the inherent tradeoff between security and cost (delay) as a multi-objective optimization problem and propose a heuristic algorithm to efficiently achieve a high level of threat reduction with minimal imposed delay. We implement and integrate WARP based on Kubernetes as the most popular container orchestration platform. Our evaluation results show that WARP can successfully mitigate up to 81% of the attacks, and our heuristic algorithm achieves up to 30% more threat reduction and 7% less delay while being 37 times faster compared to a standard optimization solution
Absolutely continuous invariant measures for piecewise convex maps of an interval with countable (infinite) number of branches
Get PDFThis thesis delves into three areas of research on dynamical systems. First, it explores the existence and exactness of Absolutely Continuous Invariant Measures (ACIM) for piecewise convex maps with countable (infinite) number of branches. Second, it employs Ulam’s method to approximate the density function of these ACIMs. Third, it investigates the existence of Absolutely Continuous Invariant Measures for piecewise concave maps using the technique of conjugation. For the first topic, we examine the existence and uniqueness of ACIMs within two distinct classes, denoted as T ∞
pc (I) and T ∞,0 pc (I), which together encompass piecewise convex maps τ : I =[0, 1] → [0, 1] with countable number of branches. We establish the necessary conditions under which these maps possess a unique ACIM, presenting multiple illustrative examples of ACIM existence.
Our findings are based on the analysis of the Frobenius-Perron operator associated with these maps, utilizing analytical techniques to gain insights into the Frobenius-Perron operator’s properties.
The main purpose of the second part of this thesis is to approximate τ by the map τn, where we construct a sequence τn with a finite number of branches. Then, approximate τn by Ulam’s method. Since piecewise convex maps have countable (infinite) number of branches, the convergence of Ulam’s method becomes more challenging, and complexity makes it harder to find a suitable sequence of approximating functions that can accurately analyze the behavior of this system across all branches.
The primary contribution of this Ph.D. thesis lies in the generalization of the existence of absolutely continuous invariant measures for piecewise convex maps defined on an interval with an infinite number of branches. In the case of T ∞pc (I), we examine piecewise convex maps with an infinite number of branches and arbitrary countable number of limit points for partition points separated from 0. For T ∞,0pc (I), we consider piecewise convex maps with countable number of branches and partition points that converge to 0. Throughout the thesis, we investigate Absolutely Continuous Invariant Measures (ACIM) for τ ∈ T ∞pc (I) and τ ∈ T ∞,0pc (I), along with exploring non-autonomous dynamical systems of maps within these classes and scrutinize the existence of ACIMs for their limit maps.
Furthermore, we investigate the approximation for ACIMs associated with piecewise convex maps with an infinite number of branches by employing Ulam’s method. This computational approach is a practical way to estimate the density functions of ACIMs and thereby facilitate their numerical analysis. We then extended our research area on ACIM for piecewise concave maps with countable number of branches. We examine the existence and uniqueness of ACIMs for two distinct classes, T ∞pcv(I) and T ∞,1pcv (I), which encompass piecewise concave mappings denoted as σ. We utilize the concept of conjugation with piecewise convex maps τ to demonstrate that σ conserves a normalized absolutely continuous invariant measure with a density that exhibits increasing behavior
The Lively, Healing, and Intergenerational Semi-Open Spaces in Older Adults Care Homes’ Courtyard: Joyful Older Adults and Children
Get PDFThe global population of older adults is rising, projected to reach 1.4 billion by 2030, surpassing the number of children by 0.1 billion and making up around 25% of the total population. Older adults are more susceptible to anxiety due to factors such as diminished self-esteem, reduced independence (both physical and financial), limited activity and mobility, loss of social connections, and chronic illnesses. Additionally, depression and loneliness are common among older adults and often go untreated. Research shows that intergenerational activities in interactive environments can enhance self-confidence, social interaction, recognition, and intellectual development for both older adults and children.
This study aims to create an intergenerational semi-open space within the courtyards of elderly care homes, tailored to the environmental needs and preferences of older adults and children. By integrating desirable features and elements, this space promotes mental well-being for both age groups, facilitating quality time together. To understand their environmental preferences, two theoretical frameworks were applied: Ulrich’s Supportive Design Theory (1991) and the Six Design Attributes by Windley and Scheidt (1980).
In the methodology, a qualitative approach using painting and writing techniques involved 25 participants, comprising 14 older adults (aged 60-95) and 9 children (aged 8-14) in Montreal. Five themes were derived from the collected data: 1. Nature, 2. Homelike, 3. Socializing, 4. Activity, and 5. Attributes of Space. The study highlighted that participants highly valued "Positive Distraction" and "Sensory Perception" as key elements in designing intergenerational spaces. "Perception of Control" was also of interest, particularly in connection with "Positive Distraction," and shared content similarities with other elements. In contrast, "Social Support" and "Sociality" were rated lower. Interestingly, all elements were mentioned by participants except for 'Legibility,' a crucial aspect of well-designed intergenerational spaces according to the 'Six Design Attributes' concept by Windley and Scheidt (1980). The study recommends that designers should still incorporate 'Legibility' into their designs, even if the participants don't mention it. Additionally, the study identified design considerations, offered recommendations, and created architectural diagrams based on the extracted themes
Experimental studies on mixing of yield stress fluids in a magnetic stirrer
Get PDFYield stress fluids exhibit a distinctive flow behavior characterized by a persistent resistance to flow until an external force surpasses their yield stress threshold. In this thesis, we investigate mixing characteristics of yield stress fluids within a magnetic mixer. The experimental apparatus comprises an acrylic rectangular mixing vessel and a high-capacity magnetic stirrer. Rheological properties of Carbopol gels were meticulously analyzed, and the yield stress was precisely determined by fitting the data with the Herschel Bulkley model. The study utilizes both Particle Image Velocimetry (PIV) and Dye Visualization techniques to comprehensively characterize the flow dynamics. Stirring characteristics, including velocity norm and cavern formation, were systematically investigated in both transient and periodic states. Notably, our experimental findings unveil a distinct trend: as the ratio of inertial forces to viscous forces increases, there is a noticeable shift in the growth rate of velocity norm and cavern area, indicative of the increasing dominance of inertial forces. Moreover, our research employing the Dye Visualization method demonstrates that the cavern's shape remains consistent regardless of the position of the rod. In contrast, PIV results reveal that at lower ratios of inertial to viscous forces, the rod's position significantly influences the cavern's shape
La traduction comme outil de promotion des perspectives autochtones : le cas de Peace and Good Order: The Case for Indigenous Justice in Canada de Harold R. Johnson
Get PDFLa montée des voix autochtones et les relations de pouvoir inégales qui ont toujours cours au Canada soulèvent des enjeux éthiques et méthodologiques en ce qui concerne la traduction de ces voix entre les langues officielles. Alors que les auteurs utilisent en partie ces dernières pour être lus et reconnus, la traduction entre celles-ci gagne en pertinence. Ainsi, se pose la question à savoir dans quelle mesure un traducteur non autochtone peut traduire des œuvres autochtones entre le français et l’anglais dans le respect du texte et des marqueurs culturels. Pour aborder ce sujet, le présent mémoire se concentre sur la traduction de l’ouvrage Peace and Good Order: The Case for Indigenous Justice in Canada de l’auteur cri Harold R. Johnson et s’applique à examiner les enjeux, l’éthique et les méthodes de traduction entourant ces littératures. Est également explorée la pertinence de leur traduction, selon les dimensions culturelle, économique et idéologique de ce processus. Il met de plus en lumière les défis spécifiques liés à la traduction des œuvres autochtones par des non-Autochtones, notamment la nécessité de remettre en question les pratiques de la traduction en contexte de relations de pouvoir asymétriques. Enfin, ces valeurs éthiques proposées sont appliquées dans le cadre d’un commentaire de traduction afin d’aborder les difficultés rencontrées dans la traduction du livre de Harold R. Johnson et les choix de traduction visant à conserver la force et l’intention du texte, tout en respectant les particularités culturelles
An Integrated Environmental and Economic Assessment for the Disposal of Food Waste from Grocery Retail Stores towards Resource Recovery
Get PDFFood waste gives rise to many environmental problems. A large amount of food waste is produced by grocery retail stores. It is therefore important to apply efficient food waste treatment technologies with minimal environmental impact and investigate the optimal approach for food waste collection, transportation, and treatment. In the present study, a life cycle impact assessment (LCIA) was conducted to analyze different food waste disposal scenarios, including incineration, landfilling, composting, anaerobic digestion, and bioconversion. The impacts of the five scenarios on the environmental, economic and social aspects were assessed. The results suggested that the landfilling scenario has the lowest net cost for the treatment of food waste, followed by the incineration scenario. The bioconversion treatment cost has the most significant positive effect on the net cost of the bioconversion scenario, and both the price and yield of compost have a significant negative effect on the net cost. The rankings of the five scenarios are the same under both weight determination methods, with the bioconversion scenario performing the best, followed by the composting scenario. The results of this study can help improve the disposal of food waste in grocery retail stores in the framework of sustainability and the circular economy
Identity, Language Attitudes, and Language Use in Spanish-Catalan Bilingual Adolescents in Catalonia
Get PDFThe link between language and identity is undeniable: language can both be a salient element of our identity, and a tool to perform and negotiate it. For multilingual speakers, this relationship becomes less straightforward as they have multiple languages (and therefore, identities) available to choose from. Said choice is particularly difficult in conflictual multilingual contexts, where the sociopolitical tensions often make language choice become a political statement. This study focuses on one of such contexts, Catalonia, with the aim to explore the language identities, attitudes and daily use of the adolescents that grew up with the sociopolitical turmoil of Catalonia’s independence attempt of 2017.
Participants included 45 high-school students from two schools located in the Barcelona metropolitan area. All participants completed ethnolinguistic questionnaires (capturing the role of language in identity, as well as their attitudes toward both Catalan and Spanish), and language use and social network surveys (measuring language entropy in different daily settings, as well as network size and intimacy in both languages).
Results revealed the expected pattern regarding the identity–language links, whereby a stronger sense of either ethnic identity was associated with greater support for that language in various social contexts. However, the strongest identity was bilingual, and it appeared to co-exist with Spanish and Catalan ethnic beliefs. Findings suggest the existence of a complex multifaceted multilingual identity in which languages are not in competition with each other
The Grande Rebeine of Lyon (1529): The Making of an Early Modern Food Riot
Get PDFFollowing a disastrous harvest, a food riot erupted in the city of Lyon in April 1529. The Grande Rebeine, as it was called, saw hundreds of ordinary Lyonnais gather to protest the handling of the grain crisis. However, the protest quickly turned into a riot as some participants decided to attack city hall, the nearby abbey, and the homes of wealthy residents, while most raided one of the city’s granaries. After over a week of rioting, control of the city was finally regained and Lyon’s authorities began the process of bringing the rioters to justice. As was made clear in surviving documentation, the focus for city councillors and jurists was to differentiate between those who looted the granary out of necessity and those who looted the homes of rich men for personal gain. This was reflected in the types of punishments the accused received. By recording the processes against a variety of individuals believed to have been involved in the Rebeine of 1529, Lyon’s civic authorities have given us the opportunity to explore a variety of themes concerning early modern popular protest culture, especially as they relate to the identities of the participants, their motivations, and the place of protest in past non-democratic societies
Damage by insect herbivores on white spruce in plantation and natural understory regeneration
Get PDFFew studies focused on non-outbreaking herbivorous insects to understand the patterns of damage they inflict on plants. We compared damage by herbivorous insects on young white spruce (Picea glauca) between natural regrowth in the understory of mixed wood forest and small extensively-managed plantations. We observed damage to foliage to quantify damage by different groups of herbivores, including leaf chewers, miners and sap-sucking species. Our hypothesis stated that trees in forest understory environments would have higher diversity of damages caused by insects but that plantation trees would have more damaged tree shoots. Our two sampling methods were branch collection, in which we collected a forty-centimeter branch and recorded foliar damage, and field surveys, where one researcher recorded foliar damage on the saplings for three-minute intervals. We also measured tree growth, canopy openness, soil temperature and humidity. We used these environmental variables in general linear models to test their effects on herbivore damage in the two habitats. The results showed that plantation and understory trees did not differ significantly in the overall amount of insect damage. There was no correlation found with any environmental factor. This pattern indicated that the plantation we sampled maintained insect biodiversity similar to that in mixed wood forests. Thus, small, extensively managed multispecies plantations can be less at risk of insect outbreaks
Expanding Horizons: A Comprehensive Exploration of Robustness, Performance and Programmable Data Plane Routing in Next Generation Data Centers
Get PDFIn recent years, data center networks have garnered significant attention, rapidly scaling up to meet the demands of the explosive nature of current applications. One notable facet driving this expansion is the pivotal role these networks play in advancing artificial intelligence (AI) and machine learning (ML). As applications like natural language processing models (e.g., OpenAI's GPT series) and image recognition algorithms for autonomous vehicles continue to evolve, data center networks provide the essential computational infrastructure required for the training and deployment of these sophisticated AI and ML models. Lately, significant efforts have been dedicated to enhancing the performance of data center networks, particularly in comparison to the often performance-lagging standard Clos-based topologies like Fat-Tree. One of the approaches for performance improvement is to use alternative data center network topologies. Consequently, researchers explored topologies based on Expander Graphs (EGs), such as Jellyfish, Xpander, and STRAT, where they exploited the sparse and incremental nature of these new topologies. This thesis focuses on investigating the STructured Re-Arranged Topology (STRAT) as a potentially robust and efficient design for next-generation data centers. To benchmark STRAT's performance against the well-known Expander data centers, a robustness framework based on geometric and connectivity-based metrics, along with throughput metrics, is adopted. The findings reveal that STRAT outperforms well-known Expander architectures, positioning them as promising alternatives that surpass the performance of present Clos-based topologies. Moreover, such observations are validated through extensive flow and packet level simulations, demonstrating STRAT's superior performance as compared to other Expanders.
Moreover, the evolution of modern network technology has witnessed a transformative shift with the advent of programmable switches, marking a paradigmatic leap in the realm of data center networks. The programmable data plane of ASIC switches, a cornerstone of this technological advancement, has emerged as a pivotal catalyst for unprecedented innovation and efficiency in data center networks. Its versatility becomes evident in diverse applications, such as employing ML for network classification, enabling dynamic routing mechanisms to achieve line-rate speeds, and implementing In-band Network Telemetry (INT) for enhanced network visibility at a granular level. These applications underscore the transformative power of the programmable data plane, transcending traditional limitations and ushering in a new era of adaptability and performance in data center networks. Building upon this foundation, this thesis introduces a novel routing algorithm that is meticulously prototyped on the BMv2 virtual programmable switch, leveraging the expressive capabilities of the P4 programming language. This implementation serves as a tangible demonstration of the intersection between routing strategies, Expander-based topologies, and the programmable data plane. Notably, the novel routing algorithm showcases superior performance improvements over traditional Equal-Cost Multi-Path (ECMP) algorithm, affirming its potential as a promising solution for harnessing the abundant path diversity inherent in the Expander next-generation data center topologies