1,018 research outputs found
Provincialising whiteness: Òyìnbó and the politics of race in Lagos, Nigeria
Much academic work on racialisation processes to date has focused on a geographically restricted range of racial regimes characterised by white supremacy. This study broadens the geographical scope of analyses by looking at race-making practices in Lagos, Nigeria. I explore the geographical specificity of race-making in Lagos through interrogation of the concept of òyìnbó – a Yorùbá word most often translated into English as ‘white person.’ By highlighting the particular meanings attached to òyìnbó, and the political work that racialisation does in this understudied context, I argue for the need to provincialise understandings of whiteness in studies of global race-making processes. The project is based upon eleven months of ethnographic fieldwork with Lagosians of different generations and social demographics at three different research sites: a senior secondary school, the University of Lagos, and at a church. My findings suggest that divergent meanings are attached to òyìnbós in these contexts, which do not universally celebrate whiteness. Rather, the practice of race-making in Lagos predominantly addresses local political concerns, and common attributes associated with òyìnbós are primarily evaluated according to local people’s own moral economy. This results in highly ambivalent attitudes to òyìnbós as individuals and to òyìnbó as trope. I suggest that these attitudes can best be explained by situating constructions of òyìnbós within their wider social context in Lagos. By centring local understandings in this way, I argue that the political practice of race-making in Lagos is not purely a reflection of a singular, global racial hierarchy, but a means of actively engaging with global and local power structures. I propose that seeking to understand the emic nature of divergent global race-making processes in this way has the potential to broaden academic understanding of these and related social phenomena
Distributed Rate Scaling in Large-Scale Service Systems
We consider a large-scale parallel-server system, where each server
independently adjusts its processing speed in a decentralized manner. The
objective is to minimize the overall cost, which comprises the average cost of
maintaining the servers' processing speeds and a non-decreasing function of the
tasks' sojourn times. The problem is compounded by the lack of knowledge of the
task arrival rate and the absence of a centralized control or communication
among the servers. We draw on ideas from stochastic approximation and present a
novel rate scaling algorithm that ensures convergence of all server processing
speeds to the globally asymptotically optimum value as the system size
increases. Apart from the algorithm design, a key contribution of our approach
lies in demonstrating how concepts from the stochastic approximation literature
can be leveraged to effectively tackle learning problems in large-scale,
distributed systems. En route, we also analyze the performance of a fully
heterogeneous parallel-server system, where each server has a distinct
processing speed, which might be of independent interest.Comment: 32 pages, 4 figure
Interoperability framework of virtual factory and business innovation
Interoperability framework of virtual factory and business innovationTask T51 Design a common schema and schema evolution framework for supporting interoperabilityTask T52 Design interoperability framework for supporting datainformation transformation service composition and business process cooperation among partnersA draft version is envisioned for month 44 which will be updated to reflect incremental changes driven by the other working packages for month 72 deliverable 7.
Security and Privacy for Modern Wireless Communication Systems
The aim of this reprint focuses on the latest protocol research, software/hardware development and implementation, and system architecture design in addressing emerging security and privacy issues for modern wireless communication networks. Relevant topics include, but are not limited to, the following: deep-learning-based security and privacy design; covert communications; information-theoretical foundations for advanced security and privacy techniques; lightweight cryptography for power constrained networks; physical layer key generation; prototypes and testbeds for security and privacy solutions; encryption and decryption algorithm for low-latency constrained networks; security protocols for modern wireless communication networks; network intrusion detection; physical layer design with security consideration; anonymity in data transmission; vulnerabilities in security and privacy in modern wireless communication networks; challenges of security and privacy in node–edge–cloud computation; security and privacy design for low-power wide-area IoT networks; security and privacy design for vehicle networks; security and privacy design for underwater communications networks
Flip: Data-Centric Edge CGRA Accelerator
Coarse-Grained Reconfigurable Arrays (CGRA) are promising edge accelerators
due to the outstanding balance in flexibility, performance, and energy
efficiency. Classic CGRAs statically map compute operations onto the processing
elements (PE) and route the data dependencies among the operations through the
Network-on-Chip. However, CGRAs are designed for fine-grained static
instruction-level parallelism and struggle to accelerate applications with
dynamic and irregular data-level parallelism, such as graph processing. To
address this limitation, we present Flip, a novel accelerator that enhances
traditional CGRA architectures to boost the performance of graph applications.
Flip retains the classic CGRA execution model while introducing a special
data-centric mode for efficient graph processing. Specifically, it exploits the
natural data parallelism of graph algorithms by mapping graph vertices onto
processing elements (PEs) rather than the operations, and supporting dynamic
routing of temporary data according to the runtime evolution of the graph
frontier. Experimental results demonstrate that Flip achieves up to 36
speedup with merely 19% more area compared to classic CGRAs. Compared to
state-of-the-art large-scale graph processors, Flip has similar energy
efficiency and 2.2 better area efficiency at a much-reduced power/area
budget
Productivity and flexibility improvement of assembly lines for high-mix low-volume production. A white goods industry case
Las tendencias globales de la personalización e individualización en masa impulsan la producción industrial en serie corta y variada; y por tanto una gran variedad de productos en pequeñas cantidades. Por ello, la customización en masa precisa de sistemas de ensamblaje que sean a la vez altamente productivos y flexibles, a diferencia de la tradicional oposición entre ambas características. La llamada cuarta revolución industrial trae diversas tecnologías habilitadoras que podrían ser útiles para abordar este problema. Sin embargo, las metodologías para implementar el ensamblaje 4.0 todavía no han sido resueltas. De hecho, para aprovechar todas las ventajas potenciales de la Industria 4.0, es necesario contar con un nivel previo de excelencia operacional y un análisis holístico de los sistemas productivos. Esta tesis tiene como objetivo entender y definir cómo mejorar la productividad y la flexibilidad de las operaciones de montaje en serie corta y variada.Esta meta se ha dividido en tres objetivos. El primer objetivo consiste en comprender las relaciones entre la Industria 4.0 y las operaciones de ensamblaje, así como sus implicaciones para los operarios. El segundo objetivo consiste en desarrollar una metodología y las herramientas necesarias para evaluar el rendimiento de diferentes configuraciones de cadenas de ensamblaje. El último objetivo consiste en el diseño de sistemas de ensamblaje que permitan incrementar su productividad al menos un 25 %, produciendo en serie corta y variada, mediante la combinación de puestos de montaje manual y estaciones automatizadas.Para abordar la fase de comprensión y definición del problema, se llevó a cabo una revisión bibliográfica sistemática y se desarrolló un marco conceptual para el Ensamblaje 4.0. Se desarrollaron, verificaron y validaron dos herramientas de evaluación del rendimiento: un modelo matemático analítico y varios modelos de simulación por eventos discretos. Para la verificación, y como punto de partida para los análisis, se ha utilizado un caso de estudio industrial de un fabricante global de electrodomésticos. Se han empleado múltiples escenarios de simulación y técnicas de diseño de experimentos para investigar tres cuestiones clave.En primer lugar, se identificaron los factores más críticos para el rendimiento de líneas de montaje manuales multi-modelo. En segundo lugar, se analizó el rendimiento de líneas de montaje semiautomáticas paralelas con operarios móviles en comparación con líneas semiautomáticas o manuales con operarios fijos, empleando diversos escenarios de demanda en serie corta y variada. Por último, se investigó el uso de trenes milkrun para la logística interna de líneas de ensamblaje multi-modelo bajo la influencia de perturbaciones.Los resultados de las simulaciones muestran que las líneas paralelas con operarios móviles pueden superar a las de operarios fijos en cualquier escenario de demanda, alcanzando como mínimo el objetivo de mejorar la productividad en un 25% o más. También permiten reducir cómodamente el número de operarios trabajando en la línea sin afectar negativamente al equilibrado de la misma, posibilitando la producción eficiente de bajo volumen. Los resultados de las simulaciones de logística interna indican que los milkrun pueden proteger las líneas de ensamblaje de las perturbaciones originadas en procesos aguas arriba.Futuras líneas de investigación en base a los resultados obtenidos en esta tesis podrían incluir la expansión e integración de los modelos de simulación actuales para analizar las cadenas de montaje paralelas con operarios móviles incorporando logística, averías y mantenimiento, problemas de control de calidad y políticas de gestión de los retrabajos. Otra línea podría ser el uso de diferentes herramienta para el análisis del desempeño como, por ejemplo, técnicas de programación de la producción que permitan evaluar el desempeño operacional de diferentes configuraciones de cadenas de montaje con operarios móviles, tanto en términos de automatización como de organización en planta. Podrían incorporarse tecnologías de la Industria 4.0 a los modelos de simulación para evaluar su impacto operacional global ¿como cobots para ensamblaje o para la manipulación de materiales, realidad aumentada para el apoyo cognitivo a los operarios, o AGVs para la conducciónde los trenes milkrun. Por último, el trabajo presentado en esta tesis acerca las líneas de ensamblaje semiautomáticas con operarios móviles a su implementación industrial.<br /
Komponentenbasierte dynamische Modellierung von Energiesystemen und Energiemanagement-Strategien für ein intelligentes Stromnetz im Heimbereich
The motivation of this work is to present an energy cost reduction concept in a home area power network (HAPN) with intelligent generation and flexible load demands. This study endeavors to address the energy management system (EMS) and layout-design challenges faced by HAPN through a systematic design approach. The growing demand for electricity has become a significant burden on traditional power networks, prompting power engineers to seek ways to improve their efficiency. One such solution is to integrate dispersed generation sources, such as photovoltaic (PV) and storage systems, with an appropriate control mechanism at the distribution level. In recent years, there has been a significant increase in interest in the installation of PV-Battery systems, due to their potential to reduce carbon emissions and lower energy costs. This research proposes an optimal economic power dispatch strategy using Model Predictive Control (MPC) to enhance the overall performance of HAPN. A hybrid AC/DC microgrid concept is proposed to address the control choices made by the appliance scheduling and hybrid switching approaches based on a linear programming optimization framework. The suggested optimization criteria improve consumer satisfaction, minimize grid disconnections, and lower overall energy costs by deploying inexpensive clean energy generation and control. Various examples from actual case study demonstrate the use of the established EMS and design methodology.Die Motivation dieser Arbeit besteht darin, ein Konzept zur Senkung der Energiekosten in einem Heimnetzwerk (HAPN) mit intelligenter Erzeugung und exiblen Lastanforderungen vorzustellen. Im Rahmen dieser Forschungsarbeit wird ein Entwurf für ein HAPN entwickelt, indem das Energiemanagementsystem (EMS) und der Entwurf des Layouts auf der Grundlage des Systemmodells und der betrieblichen Anforderungen gelöst werden. Die steigende Nachfrage nach Elektrizität ist für traditionelle Stromnetze kostspielig und infrastrukturintensiv. Daher konzentrieren sich Energietechniker darauf, die Effizienz der derzeitigen Netze zu erhöhen. Dies kann durch die Integration verteilter Erzeugungsanlagen (z. B. Photovoltaik (PV), Speicher) mit einem geeigneten Kontrollmechanismus für das Energiemanagement auf der Verteilungsseite erreicht werden. Darüber hinaus hat das Interesse an der Installation von PV-Batterie-basierten Systemen aufgrund der Reduzierung der CO2-Emissionen und der Senkung der Energiekosten erheblich zugenommen. Es wird eine optimale wirtschaftliche Strategie für den Energieeinsatz unter Verwendung einer modellprädiktiven Steuerung (MPC) entwickelt. Es wird zudem ein hybrides AC/DC-Microgrid-Konzept vorgeschlagen, um die Steuerungsentscheidungen, die von den Ansätzen der Geräteplanung und der hybriden Umschaltung getroffen werden, auf der Grundlage eines linearen Programmierungsoptimierungsrahmens zu berücksichtigen. Die vorgeschlagenen Optimierungskriterien verbessern die Zufriedenheit der Verbraucher, minimieren Netzabschaltungen und senken die Gesamtenergiekosten durch den Einsatz von kostengünstiger und sauberer Energieerzeugung. Verschiedene Beispiele aus einer Fallstudie demonstrieren den Einsatz des entwickelten EMS und der Entwurfsmethodik
Sharing Economy Last Mile Delivery: Three Essays Addressing Operational Challenges, Customer Expectations, and Supply Uncertainty
Last mile delivery has become a critical competitive dimension facing retail supply chains. At the same time, the emergence of sharing economy platforms has introduced unique operational challenges and benefits that enable and inhibit retailers’ last mile delivery goals. This dissertation investigates key challenges faced by crowdshipping platforms used in last mile delivery related to crowdsourced delivery drivers, driver-customer interaction, and customer expectations. We investigate the research questions of this dissertation through a multi-method design approach, complementing a rich archival dataset comprised of several million orders retrieved from a Fortune 100 retail crowdshipping platform, with scenario-based experiments. Specifically, the first study analyzes the impact of delivery task remuneration and operational characteristics that impact drivers’ pre-task, task, and post-task behaviors. We found that monetary incentives are not the sole factor influencing drivers’ behaviors. Drivers also consider the operational characteristics of the task when accepting, performing, and evaluating a delivery task. The second study examines a driver’s learning experience relative to a delivery task and the context where it takes place. Results show the positive impact of driver familiarity on delivery time performance, and that learning enhances the positive effect. Finally, the third study focuses on how delivery performance shape customers’ experience and future engagement with the retailer, examining important contingency factors in these relationships. Findings support the notion that consumers time-related expectations on the last mile delivery service influence their perceptions of the delivery performance, and their repurchase behaviors. Overall, this dissertation provides new insights in this emerging field that advance theory and practice
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