8,677 research outputs found
Beam scanning by liquid-crystal biasing in a modified SIW structure
A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium
Redefining Community in the Age of the Internet: Will the Internet of Things (IoT) generate sustainable and equitable community development?
There is a problem so immense in our built world that it is often not fully realized. This problem is the disconnection between humanity and the physical world. In an era of limitless data and information at our fingertips, buildings, public spaces, and landscapes are divided from us due to their physical nature. Compared with the intense flow of information from our online world driven by the beating engine of the internet, our physical world is silent. This lack of connection not only has consequences for sustainability but also for how we perceive and communicate with our built environment in the modern age. A possible solution to bridge the gap between our physical and online worlds is a technology known as the Internet of Things (IoT). What is IoT? How does it work? Will IoT change the concept of the built environment for a participant within it, and in doing so enhance the dynamic link between humans and place? And what are the implications of IoT for privacy, security, and data for the public good? Lastly, we will identify the most pressing issues existing in the built environment by conducting and analyzing case studies from Pomona College and California State University, Northridge. By analyzing IoT in the context of case studies we can assess its viability and value as a tool for sustainability and equality in communities across the world
Interview with Wolfgang Knauss
An oral history in four sessions (September 2019–January 2020) with Wolfgang Knauss, von Kármán Professor of Aeronautics and Applied Mechanics, Emeritus. Born in Germany in 1933, he speaks about his early life and experiences under the Nazi regime, his teenage years in Siegen and Heidelberg during the Allied occupation, and his move to Pasadena, California, in 1954 under the sponsorship of a local minister and his family. He enrolled in Caltech as an undergraduate in 1957, commencing a more than half-century affiliation with the Institute and GALCIT (today the Graduate Aerospace Laboratories of Caltech). He recalls the roots of his interest in aeronautics, his PhD solid mechanics studies with his advisor, M. Williams, and the GALCIT environment in the late 1950s and 1960s at the dawn of the Space Age, including the impact of Sputnik and classes with NASA astronauts. He discusses his experimental and theoretical work on materials deformation, dynamic fracture, and crack propagation, including his solid-propellant fuels research for NASA and the US Army, wide-ranging programs with the US Navy, and his pioneering micromechanics investigations and work on the time-dependent fracture of polymers in the 1990s.
He offers his perspective on GALCIT’s academic culture, its solid mechanics and fluid mechanics programs, and its evolving administrative directions over the course of five decades, as well as its impact and reputation both within and beyond Caltech. He describes his work with Caltech’s undergraduate admissions committee and his scientific collaborations with numerous graduate students and postdocs and shares his recollections of GALCIT and other Caltech colleagues, including C. Babcock, D. Coles, R.P. Feynman, Y.C. Fung, G. Neugebauer, G. Housner, D. Hudson, H. Liepmann, A. Klein, G. Ravichandran, A. Rosakis, A. Roshko, and E. Sechler.
Six appendices contributed by Dr. Knauss, offering further insight into his life and career, also form part of this oral history and are cross-referenced in the main text
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Including children with disabilities in Colombian Escuela Nueva schools
Like many countries in the Global South, Colombia has committed itself to providing quality, inclusive education for children with disabilities. However, while there is general agreement on the principle of inclusive education as something to be pursued, its meaning and nature is contested. Furthermore, a growing body of literature has questioned the relevance and application of models of inclusive education that have been generated in countries of the Global North, and subsequently, exported to Southern contexts. Moreover, there is a notable absence of literature that engages with how to operationalise inclusive education in a way that acknowledges, and is responsive to, the differing realities and priorities of rural contexts in countries of the Global South.
Colombian educators have developed and implemented a successful child-centred model of rural education, called ‘Escuela Nueva’. As a learner-centred approach for multigrade classrooms, its design includes elements that could support the education of children with disabilities: children of different ages and abilities learn at their own pace, working in teams through the provision of self- instructional learner guides; participatory tools build class cohesion; and student committees contribute to decision-making in the school. In contrast to traditional models of teacher training in Colombia, teachers are trained using the same principles and materials as those that they will use in the classroom and learn how to facilitate, rather than direct, lessons. However, there is very little research that has explored teacher practice and children’s experiences in rural contexts, whilst none has examined both Escuela Nueva and disability. Consequently, my research aimed to explore how the school staff, parents and children of five rural Escuela Nueva schools in Colombia, understood and addressed the educational needs of children with disabilities. Adopting a qualitative case study approach, I conducted 46 interviews and 15 non-participant classroom observations across the five rural schools of Las Colinas, over a period of eight months. This included interviews with 11 school staff, 14 parents and five senior staff from Foundation Escuela Nueva. To seek the views of children, I
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used a multi-method visual participatory approach with 53 children aged between 7 and 11 years, of whom, 26 were children with disabilities.
My findings suggest that, while Colombian legislation advocates for a biopsychosocial understanding of disability, all participants understood disability as an individual deficit, thus reflecting the medical model of disability. Consequently, the impact of intersecting factors, such as poverty and rural location, on parents’ ability to support their child with a disability were often not recognised by teachers. Moreover, the bureaucratic disability diagnosis and support systems are designed for urban populations and do not recognise the challenges that rural parents face when trying to access them. Thus, multiple disconnects were observed between state systems, schools and parents.
Challenging deficit accounts of rural teacher practice, my research into how children’s needs were addressed in EN classrooms revealed that the majority of teachers delivered high quality, inclusive teaching using the EN approach. Nevertheless, the findings problematised some elements of the EN model in terms of the extent to which they were able to support children with disabilities. My research revealed how the capacity of an EN teacher to deliver inclusive education is affected by a range of factors at multiple levels, of which the EN materials and tools are just one. Emphasising the role of context, teachers located in small, single-class schools had increased demands on their time, but less access to support from colleagues, than those in multi-class schools. Moreover, no teachers had received training on disability and the Escuela Nueva microcentre support structure for teacher practice had not been sustained. Consequently, I argue that, not only should state and school processes address the needs of the child, but also, the needs of those that are implementing them. Teachers require ongoing, situated, support that addresses not only support for their practice, but also, includes processes that build upon local strengths to address the disconnects and dilemmas that teachers and parents are facing within their context
Industry 4.0: product digital twins for remanufacturing decision-making
Currently there is a desire to reduce natural resource consumption and expand circular business principles whilst Industry 4.0 (I4.0) is regarded as the evolutionary and potentially disruptive movement of technology, automation, digitalisation, and data manipulation into the industrial sector. The remanufacturing industry is recognised as being vital to the circular economy (CE) as it extends the in-use life of products, but its synergy with I4.0 has had little attention thus far. This thesis documents the first investigating into I4.0 in remanufacturing for a CE contributing a design and demonstration of a model that optimises remanufacturing planning using data from different instances in a product’s life cycle.
The initial aim of this work was to identify the I4.0 technology that would enhance the stability in remanufacturing with a view to reducing resource consumption. As the project progressed it narrowed to focus on the development of a product digital twin (DT) model to support data-driven decision making for operations planning. The model’s architecture was derived using a bottom-up approach where requirements were extracted from the identified complications in production planning and control that differentiate remanufacturing from manufacturing. Simultaneously, the benefits of enabling visibility of an asset’s through-life health were obtained using a DT as the modus operandi. A product simulator and DT prototype was designed to use Internet of Things (IoT) components, a neural network for remaining life estimations and a search algorithm for operational planning optimisation. The DT was iteratively developed using case studies to validate and examine the real opportunities that exist in deploying a business model that harnesses, and commodifies, early life product data for end-of-life processing optimisation. Findings suggest that using intelligent programming networks and algorithms, a DT can enhance decision-making if it has visibility of the product and access to reliable remanufacturing process information, whilst existing IoT components provide rudimentary “smart” capabilities, but their integration is complex, and the durability of the systems over extended product life cycles needs to be further explored
Estudo do IPFS como protocolo de distribuição de conteúdos em redes veiculares
Over the last few years, vehicular ad-hoc networks (VANETs) have been the
focus of great progress due to the interest in autonomous vehicles and in
distributing content not only between vehicles, but also to the Cloud. Performing
a download/upload to/from a vehicle typically requires the existence
of a cellular connection, but the costs associated with mobile data transfers
in hundreds or thousands of vehicles quickly become prohibitive. A VANET
allows the costs to be several orders of magnitude lower - while keeping the
same large volumes of data - because it is strongly based in the communication
between vehicles (nodes of the network) and the infrastructure.
The InterPlanetary File System (IPFS) is a protocol for storing and distributing
content, where information is addressed by its content, instead of
its location. It was created in 2014 and it seeks to connect all computing
devices with the same system of files, comparable to a BitTorrent swarm
exchanging Git objects. It has been tested and deployed in wired networks,
but never in an environment where nodes have intermittent connectivity,
such as a VANET. This work focuses on understanding IPFS, how/if it can
be applied to the vehicular network context, and comparing it with other
content distribution protocols.
In this dissertation, IPFS has been tested in a small and controlled network
to understand its working applicability to VANETs. Issues such as neighbor
discoverability times and poor hashing performance have been addressed.
To compare IPFS with other protocols (such as Veniam’s proprietary solution
or BitTorrent) in a relevant way and in a large scale, an emulation platform
was created. The tests in this emulator were performed in different times of
the day, with a variable number of files and file sizes. Emulated results show
that IPFS is on par with Veniam’s custom V2V protocol built specifically for
V2V, and greatly outperforms BitTorrent regarding neighbor discoverability
and data transfers.
An analysis of IPFS’ performance in a real scenario was also conducted, using
a subset of STCP’s vehicular network in Oporto, with the support of
Veniam. Results from these tests show that IPFS can be used as a content
dissemination protocol, showing it is up to the challenge provided by a
constantly changing network topology, and achieving throughputs up to 2.8
MB/s, values similar or in some cases even better than Veniam’s proprietary
solution.Nos últimos anos, as redes veiculares (VANETs) têm sido o foco de grandes
avanços devido ao interesse em veículos autónomos e em distribuir conteúdos,
não só entre veículos mas também para a "nuvem" (Cloud). Tipicamente,
fazer um download/upload de/para um veículo exige a utilização
de uma ligação celular (SIM), mas os custos associados a fazer transferências
com dados móveis em centenas ou milhares de veículos rapidamente se
tornam proibitivos. Uma VANET permite que estes custos sejam consideravelmente
inferiores - mantendo o mesmo volume de dados - pois é fortemente
baseada na comunicação entre veículos (nós da rede) e a infraestrutura.
O InterPlanetary File System (IPFS - "sistema de ficheiros interplanetário")
é um protocolo de armazenamento e distribuição de conteúdos, onde a informação
é endereçada pelo conteúdo, em vez da sua localização. Foi criado
em 2014 e tem como objetivo ligar todos os dispositivos de computação num
só sistema de ficheiros, comparável a um swarm BitTorrent a trocar objetos
Git. Já foi testado e usado em redes com fios, mas nunca num ambiente
onde os nós têm conetividade intermitente, tal como numa VANET. Este
trabalho tem como foco perceber o IPFS, como/se pode ser aplicado ao
contexto de rede veicular e compará-lo a outros protocolos de distribuição
de conteúdos.
Numa primeira fase o IPFS foi testado numa pequena rede controlada, de
forma a perceber a sua aplicabilidade às VANETs, e resolver os seus primeiros
problemas como os tempos elevados de descoberta de vizinhos e o fraco desempenho
de hashing.
De modo a poder comparar o IPFS com outros protocolos (tais como a
solução proprietária da Veniam ou o BitTorrent) de forma relevante e em
grande escala, foi criada uma plataforma de emulação. Os testes neste emulador
foram efetuados usando registos de mobilidade e conetividade veicular
de alturas diferentes de um dia, com um número variável de ficheiros e
tamanhos de ficheiros. Os resultados destes testes mostram que o IPFS está
a par do protocolo V2V da Veniam (desenvolvido especificamente para V2V
e VANETs), e que o IPFS é significativamente melhor que o BitTorrent no
que toca ao tempo de descoberta de vizinhos e transferência de informação.
Uma análise do desempenho do IPFS em cenário real também foi efetuada,
usando um pequeno conjunto de nós da rede veicular da STCP no Porto,
com o apoio da Veniam. Os resultados destes testes demonstram que o
IPFS pode ser usado como protocolo de disseminação de conteúdos numa
VANET, mostrando-se adequado a uma topologia constantemente sob alteração,
e alcançando débitos até 2.8 MB/s, valores parecidos ou nalguns
casos superiores aos do protocolo proprietário da Veniam.Mestrado em Engenharia de Computadores e Telemátic
Strategies for Developing Entrepreneurial Capacity and Capability in Coffee Industry Sect in Timor-Leste
The main objective of this research is to increase the capacity and capability of entrepreneurship
through the development of an entrepreneurial education model based on the entrepreneurial
ecosystem in the coffee industry sector in Timor-Leste. The coffee industry has a significant
contribution to Timor-Leste's economic growth. Therefore, the growth and the coffee industry
must be maintained in the long term. As an effort to maintain the continuity of the coffee
industry, we conduct research on every important role in the growth of the coffee industry,
namely the Government, Coffee Shop Owners, Academics, the Coffee Industry, and NGOs
which are then carried out in collaboration with the Pentahelix model to lead capacity building
and entrepreneurial capabilities, especially in the coffee industry. This study involved 23
informants spread from the Pentahelix, namely: entrepreneurs, government, universities,
industry, and the community. The five parties will be interviewed separately for their opinions
and views on the pattern of partnership and collaboration within Pentahelix.
This study found that concerns relevant instruments including internal factors, ability factors,
factors (PESTLE analysis), prospects, and obstacles in increasing entrepreneurial capacity and
capability. And it was found that by increasing efficiency in partnership and collaboration of all
parties in Pentahelix, it can promote and awaken the entrepreneurial spirit of the Timorese
people and effectively increase the productivity of the coffee business
Trust and transparency in an age of surveillance
Investigating the theoretical and empirical relationships between transparency and trust in the context of surveillance, this volume argues that neither transparency nor trust provides a simple and self-evident path for mitigating the negative political and social consequences of state surveillance practices.
Dominant in both the scholarly literature and public debate is the conviction that transparency can promote better-informed decisions, provide greater oversight, and restore trust damaged by the secrecy of surveillance. The contributions to this volume challenge this conventional wisdom by considering how relations of trust and policies of transparency are modulated by underlying power asymmetries, sociohistorical legacies, economic structures, and institutional constraints. They study trust and transparency as embedded in specific sociopolitical contexts to show how, under certain conditions, transparency can become a tool of social control that erodes trust, while mistrust - rather than trust - can sometimes offer the most promising approach to safeguarding rights and freedom in an age of surveillance. The first book addressing the interrelationship of trust, transparency, and surveillance practices, this volume will be of interest to scholars and students of surveillance studies as well as appeal to an interdisciplinary audience given the contributions from political science, sociology, philosophy, law, and civil society
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