Two topics in fading channels with a strict delay constraint and a resolution-constrained feedback link are treated in this thesis. First, a multi-layer variable-rate single-antenna communication system with quantized feedback, where the expected rate is chosen as the performance measure, is studied under both short-term and long-term power constraints. Iterative algorithms exploiting results in the literature of parallel broadcast channels are developed to design the system parameters. A necessary and sufficient condition for single-layer coding to be optimal is derived. In contrast to the ergodic case, it is shown that a few bits of feedback information can improve the expected rate dramatically. The role of multi-layer coding, however, reduces quickly as the resolution of the feedback link increases. The other part of the thesis deals with partial power control systems utilizing quantized feedback to minimize outage probability, with an emphasis on the diversity-multiplexing tradeoff. An index mapping with circular structure is shown to be optimal and the design is facilitated with a justified Gaussian approximation. The diversity gain as a function of the feedback resolution is analyzed. The results are then extended to characterize the entire diversity-multiplexing tradeoff curve of multiple-antenna channels with resolution-constrained feedback. Adaptive-rate communication is also studied, where the concept of minimum multiplexing gain is introduced. It is shown that the diversity gain of a system increases significantly even with coarsely quantized feedback, especially at low multiplexing gains. / QC 20101117

Multi-/many-core heterogeneous architectures are shaping current and upcoming generations of compute-centric platforms which are widely used starting from mobile and wearable devices to high-performance cloud computing servers. Heterogeneous many-core architectures sought to achieve an order of magnitude higher energy efficiency as well as computing performance scaling by replacing homogeneous and power-hungry general-purpose processors with multiple heterogeneous compute units supporting multiple core types and domain-specific accelerators. Drifting from homogeneous architectures to complex heterogeneous systems is heavily adopted by chip designers and the silicon industry for more than a decade. Recent silicon chips are based on a heterogeneous SoC which combines a scalable number of heterogeneous processing units from different types (e.g. CPU, GPU, custom accelerator). This shifting in computing paradigm is associated with several system-level design challenges related to the integration and communication between a highly scalable number of heterogeneous compute units as well as SoC peripherals and storage units. Moreover, the increasing design complexities make the production of heterogeneous SoC chips a monopoly for only big market players due to the increasing development and design costs. Accordingly, recent initiatives towards agile hardware development open-source tools and microarchitecture aim to democratize silicon chip production for academic and commercial usage. Agile hardware development aims to reduce development costs by providing an ecosystem for open-source hardware microarchitectures and hardware design processes. Therefore, heterogeneous many-core development and customization will be relatively less complex and less time-consuming than conventional design process methods. In order to provide a modular and agile many-core development approach, this dissertation proposes a development platform for heterogeneous and self-adaptive many-core architectures consisting of a scalable number of heterogeneous tiles that maintain design regularity features while supporting heterogeneity. The proposed platform hides the integration complexities by supporting modular tile architectures for general-purpose processing cores supporting multi-instruction set architectures (multi-ISAs) and custom hardware accelerators. By leveraging field-programmable-gate-arrays (FPGAs), the self-adaptive feature of the many-core platform can be achieved by using dynamic and partial reconfiguration (DPR) techniques. This dissertation realizes the proposed modular and adaptive heterogeneous many-core platform through three main contributions. The first contribution proposes and realizes a many-core architecture for heterogeneous ISAs. It provides a modular and reusable tilebased architecture for several heterogeneous ISAs based on open-source RISC-V ISA. The modular tile-based architecture features a configurable number of processing cores with different RISC-V ISAs and different memory hierarchies. To increase the level of heterogeneity to support the integration of custom hardware accelerators, a novel hybrid memory/accelerator tile architecture is developed and realized as the second contribution. The hybrid tile is a modular and reusable tile that can be configured at run-time to operate as a scratchpad shared memory between compute tiles or as an accelerator tile hosting a local hardware accelerator logic. The hybrid tile is designed and implemented to be seamlessly integrated into the proposed tile-based platform. The third contribution deals with the self-adaptation features by providing a reconfiguration management approach to internally control the DPR process through processing cores (RISC-V based). The internal reconfiguration process relies on a novel DPR controller targeting FPGA design flow for RISC-V-based SoC to change the types and functionalities of compute tiles at run-time.

No description available.

The process of FPGA reconfiguration is to recompile a design and then update the FPGA configuration correspondingly. Traditionally, FPGA design compilation follows the way how hardware is compiled for achieving high performance, which requires a long computation time. How to efficiently compile a design becomes the bottleneck for FPGA reconfiguration. It is promising to apply some techniques or concepts from software to facilitate FPGA reconfiguration. This dissertation explores such an idea by utilizing three types of low-level manipulation on FPGA logic and routing resources, i.e. relocating, mapping/placing, and routing. It implements an FMA technique for "fast reconfiguration". The FMA makes use of the software compilation technique of reusing pre-compiled libraries for explicitly reducing FPGA compilation time. Based the software concept of Autonomic Computing, this dissertation proposes to build an Autonomous Adaptive System (AAS) to achieve "self-reconfiguration". An AAS absorbs the computing complexity into itself and compiles the desired change on its own. For routing, an FPGA router is developed. This router is able to route the MCNC benchmark circuits on five Xilinx devices within 0.35 ~ 49.05 seconds. Creating a routing-free sandbox with this router is 1.6 times faster than with OpenPR. The FMA uses relocating to load pre-compiled modules and uses routing to stitch the modules. It is an essential component of TFlow, which achieves 8 ~ 39 times speedup as compared to the traditional ISE flow on various test cases. The core part of an AAS is a lightweight embedded version of utilities for managing the system's hardware functionality. Two major utilities are mapping/placing and routing. This dissertation builds a proof-of-concept AAS with a universal UART transmitter. The system autonomously instantiates the circuit for generating the desired BAUD rate to adapt to the requirement of a remote UART receiver. / Ph. D.

<p dir="ltr">Each year, approximately 1.35 million people die globally due to vehicle crashes, and in the United States alone, 42,915 traffic fatalities were recorded in 2021, reflecting a 10.5% increase from 2020 and an 18% increase from 2019. Driver fatigue and drowsiness significantly contribute to these fatalities, as fatigue severely impairs a driver’s alertness and responsiveness, leading to a higher risk of accident. Given the prevalence of drowsy driving accidents, it is crucial to implement advanced systems that alert drivers to their drowsy condition, significantly reducing traffic-related deaths and injuries. While these systems have shown significant effects in reducing the risks related to drowsy driving, most commercially available and widely researched alert systems heavily rely on auditory and visual sensory channels. These modalities may cause "alarm fatigue," leading drivers to ignore or deactivate the systems entirely, and result in a lower driving experience. Due to their frequent occurrence and potential annoyance, the National Highway Traffic Safety Administration (NHTSA) recommends that auditory warnings, which are the most commonly used modality in current driver alert systems, are generally unsuitable for first-stage cautionary alerts. Despite NHTSA human factors guidance, most in-vehicle warning systems consist of auditory and visual modalities, even in the first cautionary stage alerts. Therefore, advanced alerting systems that balance the functionality of alerts and driving experience, using non-audio and non-visual modalities, are needed.</p><p dir="ltr">With this motivation, the purpose of this Ph.D. dissertation work is to propose a novel approach to both olfactory and climate adaptive alerting systems and demonstrate their usability in in-vehicle engagement experiences. In Study 1 (Chapter 3), the use of behavioral metrics and physiological sensing was validated to assess drivers' cognitive states during driving. This validation laid the groundwork for the future evaluation of the effects of the proposed alerting system in Study 2(Chapter 4) and Study 3 (Chapter 5). In Study 2, the impact of olfactory and climate stimuli on drivers' cognitive states was investigated by studying time-variant changes. This investigation helped determine if the proposed stimuli can be effectively utilized in driver alerting systems. In Study 3, the proposed sensory-integrated alerting adaptive systems were developed and evaluated for their effect on drivers in a drowsy state. The evaluations focused on the systems’ abilities to provide a sufficient salient effect, sustained arousal effect, and driver satisfaction.</p><p dir="ltr">This dissertation introduces a new approach to driving alert systems to ensure both alert functionality and driving experience. Ultimately, this work offers a new direction for developing advanced alerting systems, particularly for first-stage warnings.</p>

National and state-based assessments have been a common practice for the past several decades. These assessments often come with high-stake consequences for students and schools, which tends towards the creation of a test-centric environment where educators prioritize test-based instruction to prepare students to be successful on those assessments. The over-arching purpose of this qualitative study was to explore how mandated high-stakes testing influences educators specifically within a complex system by first seeking to identify ways educators at different levels within the system—the classroom, campus, and district levels—perceive these testing influences. This study is based on complexity theory with a particular focus on complex adaptive systems (CAS) and frameworks from human systems dynamics (HSD), which helped to identify key tensions within a complex learning ecology. This study used thematic analysis of interview data from the classroom, campus, and district levels. Analysis also included mapping the emergent themes and patterns onto a CAS model for each level. Findings revealed a tension between a complicated, linear approach and a complex approach to curricular and instructional decisions that is moving those decisions ever closer to standardization. This study includes implications and recommendations for balancing these tensions for a healthy, complex learning ecology.

This study set out to explore how Official Development Assistance was practised in South Africa. An exploratory narrative design was followed to uncover the ‘strategy in the skin’ of strategy practitioners in the unit of analysis and to respond, therefore, to the research questions. This study has contributed to the body of knowledge in that it has brought together an alternative confluence of three theoretical perspectives of strategy as practice; complex adaptive systems and organisational hypocrisy and has explored the impact of the practice lens on these standpoints. While there has been extensive research on each of the theoretical perspectives, there has not yet been a study that has drawn together the three perspectives in relation to an empirical unit of analysis such as Official Development Assistance practices and practitioners. The study responded to a knowledge gap in relation to how public sector organisations, such as government units and the strategy practitioners of such units, practice strategy beyond the reified, formalised conceptions of strategy and in relation to their inhabiting complex, political organisational systems. The study arrived at two central theoretical findings. Firstly, that strategising represents a calibration of strategic practices towards strategic outcomes through the activities of complex adaptive practitioners v within the more politically inclined organisation. Secondly, that beyond the text of strategy, there is sub-text that is equally part of the micro strategy towards strategic outcomes.The skilful and sometimes delicate balancing act, that strategists perform to legitimise the calibrated combinations of action and politics in organisational strategy, equally needs nuanced, subtle and more complex forms of organisational communication. The study, therefore, makes the claim that complex adaptive systems and the characteristics of political organisations (as not being geared to action) are inherently broadened through the multiple dimensions of the practice turn and strategy as sub-text. The research confirmed that strategy as practice is a useful lens to understand strategy beyond the formally documented scripts and espoused pronouncements of strategy within organisational studies / Business Management / Thesis (D. B. L.)

Which form of exchange governance performs better in a dynamic environment? This remains an unanswered question in the transaction cost analysis (TCA) and relational exchange literatures. Some researchers purport that transactional governance provides superior performance by providing firms the flexibility to change suppliers. Others suggest that relational governance leads to superior performance because of the willingness of both parties to adapt. Reviews of TCA have turned up ambivalent empirical findings with regard to the effects of uncertainty despite a track record of strong empirical support for other predictions. Because most of TCA and relational exchange theories' predictions enjoy strong support, this research builds upon these theories to propose a theoretical modeling framework for a dynamic environment in a supply chain network (SCN) setting. This dissertation extends TCA and relational exchange to a dynamic, network environment. It uses the approach of building a simulation in order to study in detail the relationship between key exchange factors and the selection of transactional and relational exchange governance over time. This research effort extended TCA theory with a complex adaptive model of supply chain network governance evolution that attempts to link environmental, network, production, firm and exchange factors in a continuously evolving loop. The proposed framework expands transaction cost analysis' explanatory power. Results partially support past scholarly proposal that uncertainty functions as an antecedent of asset specificity rather than as an independent construct affecting governance outcome dependent upon which form of uncertainty is being considered. The successful simulation of supply chain networks as complex adaptive systems shift the focus from deterministic, confirmatory models of exchange to an exploratory, positive model. Instead of exchange governance as an outcome, it is the catalyst of the evolutionary process.

A key challenge of the Anthropocene is to advance human development without undermining critical ecosystem services. Central to this challenge is a better understanding of the interactions and feedbacks between biodiversity, ecosystem services and human well-being, which interact in dynamic and complex social-ecological systems. These relationships have been the focus of much work in the past decades, however more remains to be done to comprehensively identify and quantify them, especially at larger scales. In this thesis, a social-ecological systems approach is adopted to investigate connections between biodiversity, ecosystem services and human well-being in South Africa. The country’s high levels of biological and socio-economic diversity, as well as its emerging economy make South Africa an interesting case for exploring these connections. Using data from a variety of public sources, and at different sub-national scales, the thesis first identifies and analyses a variety of bundles of ecosystem service use. Based on these bundles, three social-ecological system archetypes were identified and mapped in South Africa, namely the green-loop (high overall use of local ecosystem services), transition, and red-loop (low overall use of local ecosystem services) systems. Further analysis explored the social and ecological drivers of these patterns, and found the distribution of systems mainly influenced by social factors including household income, gender of the household head, and land tenure. Second, this thesis uses human well-being indicators to construct, analyse and map multi-dimensional human well-being bundles. These bundles were found to spatially cluster across the landscape, and were analysed for congruence with the ecosystem service use bundles. Discrepancies in the expected overlap of ecosystem service use and human well-being were highlighted and concur with findings elsewhere and the ongoing debate in the literature on the impacts of time-lags, indicator choice and scale of these interactions. Third, biodiversity in South Africa was analysed by employing an indicator of biodiversity intactness (BII) at the population level. The BII was found to have declined by 18.3% since pre-industrial times. Biodiversity loss was linked to the potential supply of ecosystem services, as well as human well-being patterns. A potential threshold at 40% biodiversity loss was detected, beyond which population abundances decline sharply. Finally, the thesis examines multiple perspectives on ecosystem services in sustainability research, including the social-ecological systems perspective, and discusses the complementarity of the different perspectives in furthering a deeper understanding of the connections between people and ecosystems. The social-ecological systems perspective employed throughout the empirical work presented in this thesis contributed towards cross-cutting insights, the testing of new kinds of data and the development of new approaches, all of which represent important steps towards unravelling the connections between biodiversity, ecosystem services and human well-being, and contributing to the key Anthropocene challenge of sustainable development. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Manuscript. Paper 4: Manuscript.</p>

Submitted by William Justo Figueiro (williamjf) on 2015-06-13T14:34:59Z No. of bitstreams: 1 15.pdf: 1458705 bytes, checksum: 59b7f3a79abc9a4c4dcf917b8bab961f (MD5) / Made available in DSpace on 2015-06-13T14:34:59Z (GMT). No. of bitstreams: 1 15.pdf: 1458705 bytes, checksum: 59b7f3a79abc9a4c4dcf917b8bab961f (MD5) Previous issue date: 2014-02-24 / UNISINOS - Universidade do Vale do Rio dos Sinos / O presente estudo concebe o papel central da língua no desenvolvimento humano por meio de um agir linguageiro. Nessa perspectiva, compreende-se que a linguagem se situa em práticas interacionais e está em permanente transformação. Este estudo tem caráter empírico de cunho qualitativo, inserido na plataforma Moodle, investigando a especificidade das interações realizadas em Chats, em uma disciplina de Ensino à Distância (EAD) na perspectiva da Teoria da Complexidade (GLEICK, 1994; JOHNSON 2003; LARSENFREEMAN 1997, 2008, 2009; MORIN 2008) e do Interacionismo Sociodiscursivo - ISD (BRONCKART, 1999, 2008). A compreensão epistemológica deste estudo abarca o agir humano em desenvolvimento caracterizado como um sistema adaptativo complexo. Sendo que, a partir das práticas de nível mais baixo, mas não menos complexas, os comportamentos acabam por emergir. Assim, os interagentes desenvolvem comportamentos observáveis que emergem das condições iniciais, encaminhando-se às manifestações de auto-organização. O agir humano situado na plataforma, assim como as práticas situadas por meio de tipos específicos de discursos (BRONCKART, 1999) estão entendidos como geradores de movimentos de complexidade. As relações discursivas tecnologicamente situadas foram observadas quanto à forma como os interagentes se adaptavam ao contexto discursivo. A partir das interações analisadas, elencaram-se, então, tipos de discurso e foram propostos quatro tipos de Movimentos de Complexidade que emergiram das interações discursivas: Movimento 1 – Dinamicidade discursiva entre interagentes; Movimento 2 – Não-linearidade interacional; Movimento 3 – Adaptação de agentividade (espaço-tempo) e Movimento 4 – Comportamento emergente. A análise do agir linguageiro, situado por meio de tipos de discurso identificados, apresentou baixo índice de variação da escrita em linguagem formal; como era de se esperar, dado o caráter formal da troca entre pares. O estudo permitiu evidenciar que os tipos de discurso se adaptam na medida em que os interagentes passam por mudanças interacionais de fases co-construídas em processo, alternando entre os tipos de discurso relato interativo e relato misto interativo-teórico pela ausência do discurso teórico. / This study conceives the central role of language in the human development through language acting. In this perspective, it is comprehended that language is situated in interactional practices and it is permanently transformed. This study has an empirical character and a qualitative approach, inserted in the Moodle platform, investigating the specificity of the interactions made in Chats in a Distance Learning Environment according to the Complexity Theory perspective (GLEICK, 1989; JOHNSON 2003; LARSEN-FREEMAN 1997, 2008, 2009; MORIN 2008) and the Sociodiscursive Interactionism perspective (BRONCKART, 1999, 2008). The epistemological comprehension of this study considers that the language acting under development is characterized as a complex adaptive system, in which behaviors eventually emerge from practices of lower level, but not less complex. Then, the interactants develop observing behaviors that emerge from the initial conditions, heading towards self-organization manifestations. The situated language acting on the platform, as well as the situated practices through specific types of discourse (BRONCKART, 2008), are understood as generators of complexity movements. The ways interactants adapted themselves to the discursive context were observed as discursive relations technologically situated. From the analyzed interactions, types of discourse were established and four types of complexity movements, which emerged from the discursive interactions, were proposed: Movement 1 – Discursive Dynamics among interactants; Movement 2 – Non-Interactional linearity; Movement 3 – Agentivity Adaptation (space-time); Movement 4 – Emergent Behavior. The analysis of the situated language acting, through identified types of discourse, presented a low rate of variation in formal language use, as it was expected, due to the formal character of the exchange among pairs. The study allowed us to evidence that the types of discourse are adaptable as the interactants go through phases of interactional change coconstructed in process, alternating between interactive-reporting and mixed theoreticalinteractive types of discourse, by the absence of theoretical discourse.