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A “No Gain” Direct-Conversion IQ RF-to-Bits Receiver Without Active Linear Amplification
No full textThis work describes a direct-conversion IQ receiver (RX) that does not utilize any active linear (power) amplification, covering its design considerations, prototype implementation, and measurement verification. Only RLC components, MOS transistor (MOST) switches, and comparators are used, leading to several unique design challenges. Key among these are the fact that each block in the signal chain contributes to overall loss, together setting the RF input impedance and thereby RX input matching, plus the limited frequency selectivity of the available passive filters. By considering a fundamental minimum power consumption limit of analog-to-digital converters (ADCs) given by Vittoz, we show that applying impedance up-transformation in the RF front end (RFE) lowers the (minimal) power consumption of the back-end quantization ADC. In our proposed RX, this is implemented by a resonant monolithic transformer followed by a capacitive-stacking N-path filter/mixer (CSNPFM). The resulting RFE architecture simultaneously implements blocker rejection, frequency translation to baseband (BB), and a ~40x power consumption reduction in the back-end ADC. The poor frequency selectivity of passive integrated filters renders the implementation of anti-alias filter (AAF) challenging. To avoid their necessity, a highly oversampled delta-sigma modulator back end synchronously digitizes the CSNPFM’s output samples. A prototype RX, implemented in a 22 nm fully-depleted silicon on insulator (FD-SOI) process, has a 10 MHz RF bandwidth (BW) centered around 2.5 GHz and occupies an area of 0.14 mm 2 while consuming 10.1 mW. Its measured double-sideband (DSB) noise figure (NF) is 20.5 dB, and its out-of-band (OOB) input intercept point 3 (IIP3) and B1dB are +16 and −0.3 dBm, respectively.</p
Characterizing Hosting and Security Practices for Public-Facing LDAP Servers
No full textThe Lightweight Directory Access Protocol (LDAP)is widely used to make structured data available for standardizedlookup, which may sometimes include personal information orauthentication credentials. Previous work, including ours, foundsecurity issues such as public LDAP servers leaking sensitive in-formation without prior authentication and server configurationswith poor communication security. However, prior work did notinvestigate whether, or to what extent, the identified problemsare linked to hosting and management setups. In this paper, weaddress this gap and explore the organizations hosting public-facing LDAP servers. We identify the network segments morelikely to host LDAP instances, the products and operating systemsused, and examine the management practices related to PublicKey Infrastructure (PKI) setups for LDAP. In contrast to studieson Web and email, which have revealed strong centralizationtendencies in deployment, we show that the LDAP ecosystemis diverse, with a wide range of different hosting networks. Inthis study, we identify 69.1k LDAP instances—6.5× more thanprior work—and map these to the respective LDAP products. Wefind that 5.8% of the servers use a product that is end-of-life orruns on a deprecated OS. We identify servers using problematicX.509 certificates, e.g., those associated with publicly knownprivate keys. From our observations, we give recommendationsfor network operators to improve their security posture
New Tools for Tracking Small Invertebrates Using Harmonic Radar
No full textWe introduce two novel radar systems for tracking small invertebrates, such as insects, using a harmonic radar operating around 9 GHz/18 GHz. The first is a scanning radar that continuously measures the range and angle of tagged targets to study their movement patterns. The second is a handheld radar designed for fieldworkers to periodically re-locate tagged targets with visual and audio prompts. Preliminary field results show promising capabilities, with the scanning radar detecting tags up to 130 m, and sub-1 m localisation accuracy (at 20-30 m range). The handheld radar could function effectively within 60 m under ideal conditions. However, challenges remain, such as the dependence on the tag orientation, occlusion by vegetation/leaf litter, affixing tags, and the influence of nearby objects (including the target body). Future work will address these issues, in addition to expanding system capabilities using mobile platforms and remote monitoring using cloud processing
Facilitating African-European R&D partnership in earth observation through collaborative research:EO AFRICA R&D research calls
No full textThe EO AFRICA R&D Facility is the flagship of the EO AFRICA initiative that aims to facilitate the sustainable adoption of EO and related space technology in Africa through an African-European R&D partnership. For this purpose, the Facility supports capacity development for research by organizing tailor-made domain-specific training courses and webinars, and capacity development through research by enabling research projects co-developed and run by African and European research tandems. During its first phase in 2020-2023, the Facility launched two research project calls to support African-European collaborative efforts in developing innovative, open source EO algorithms and applications adapted to African solutions to African challenges by using cutting-edge cloud-based data access and computing infrastructure. The calls aimed at addressing emerging research topics in food security and water scarcity, making full use of the digital transformation in Africa and the observation capabilities of the ESA and Third Party EO missions. More than 100 project proposals were submitted by African and European co-investigators affiliated with public and private research institutions in 29 African and 17 European countries and covering a wide range of topics such as crop monitoring, yield forecasting, climate change, flood mapping, livestock mapping, soil monitoring, lake monitoring, biodiversity, etc. Following an exhaustive peer-review and evaluation process considering 33 criteria grouped under 6 categories, including qualifications of the project team, scientific quality of the proposed work, innovation and impact potential, use of EO data, use of cloud-based ICT infrastructure, and budget, the Facility provided financial support and ICT infrastructure to 30 research projects. Each project developed an innovative algorithm or research workflow delivered as open-source research code, preferably as interactive notebooks, together with open-access research data. The results of the research projects are also published as open-access scientific publications.In this talk, first, the details of the research calls are described starting for the preparation of the call, up to the closure of the research projects, with a special emphasis on the evaluation process. Then, an overview of the submitted proposals are provided including research questions, EO data and analysis methods, work and budget distribution, geographical distribution, and gender balance. The results of the funded projects are summarized and finally, the lessons learned from the research calls are discussed in detail, including challenges in using cloud computing infrastructure, performing collaborative research as tandems, budget utilization, and Open Science practices
Benchmaking data access and processing performance of OpenEO backends: a reproducible approach
No full textopenEO is a community-driven initiative supported by prominent research institutions, as well as cloud service providers and international agencies, that is designed to simplify the access and processing of Earth Observation (EO) data. It offers a standardized interface that allows users to interact with multiple EO data providers, cloud services, and processing engines, facilitating the efficient retrieval, analysis, and visualization of EO data. This facilitates scalable and flexible processing workflows for a broad spectrum of applications. To achieve this, openEO defines a HTTP-based API that enables communication between cloud backends with large EO datasets and frontend applications in an interoperable manner by specifying how to manage users, discover available EO data and processes on backends, execute processes and user-defined functions on backends, and download results. Currently there are different backends available that are based on various big EO data processing frameworks, such as Geotrellis, GRASS GIS/actinia, Google Earth Engine, OpenDataCube, Xarray, and Dask. There are also operational platforms that provide openEO services (i.e. openEO providers) such as Copernicus Data Space Ecosystem, EODC, and VITO. Recently, the openEO Platform also has been launched, providing federated access to various openEO services.Although openEO provides a standard mechanism to access the provided EO data and processing services, available data and processing capabilities differ between the service providers. Data availability is determined by the size of the data archives of the providers, whereas processing capabilities are largely influenced by the specific backend implementations deployed by the operators and their IT infrastructure. Although openEO provides a web portal (openEO Hub), which lists the reported capabilities of the openEO providers, limited information is available on the actual data availability and data access and processing performance of the providers. Benchmarking is crucial for assessing the performance of various openEO backends, because it provides objective and standardized measurements of efficiency, performance, and reliability. By comparing different backends under controlled conditions, it provides valuable information that enables users to select the most suitable backend for their specific needs, based on factors such as processing time and scalability. It can also help to identify strengths and weaknesses, driving improvements and optimizations by backend developers that benefit the entire user community. Eventually, it can support the development of more effective systems, and helps maintain high standards in EO data access and processing workflows.To benchmark the performance of different openEO backends and service providers, we have created an openEO benchmarking framework. Built using a unit testing approach, the framework allows for replicable testing of data availability, data access, and data processing capabilities across various backends. The results are presented in standard formats, providing both detailed reports and summaries. This poster presentation provides a comprehensive overview of the design principles and operational structure of the developed openEO benchmarking framework. It covers the framework's core features, functional capabilities, along with a comprehensive overview of the tests that are designed to assess data availability on different backends and their data access and processing performance. The results of the tests performed are summarized to provide an insight into the current state of the operational openEO providers and their services
Shaping Value:Marketing through the Lens of Design
No full textFor anyone who wants to design marketing with their head and their heart — and courage. This isn’t a book that teaches you how to become a good marketer; it’s a book that teaches you how to become a good marketing designer. Marketing isn’t approached as a component of business and management but of design. It’s this design perspective that makes this book fundamentally different from other marketing books.Using international examples — from the worlds of design, art, branding, and non-profit campaigns — you’ll learn how to shape marketing in a way that truly reflects what matters: being meaningful for customers and other stakeholders. Based on the logic of design thinking and the principle of Value-Sensitive Design, you’ll develop a strategic marketing plan in the form of a marketing design poster. This poster prioritizes customer needs while also considering the planet, society, and the future.Forget the classic 4, 5, or 7 Ps. This book invites you to approach marketing in a radically different way: design-oriented, value-driven, inclusive, and sustainable.Dive into inspiring examples—from stunning campaigns to questionable marketing practices—and learn from what works and what rubs you the wrong way.Use creative tools to design a value proposition and a meaningful marketing strategy.Connect marketing with social impact and demonstrate that every step toward change counts.This book is an ode to curiosity, creativity, and imagination. You’ll be challenged to think differently about marketing, and to see, create, and act differently. Here, research and design go hand in hand—following your curiosity is just as important as following the plan. This book encourages you to not only gain new knowledge but also to acquire a different mindset: one of engagement and empathy, of deepening and experimenting, and of analysis and creativity
Axial oscillations of a sphere in a rotating cylinder
No full textThe flow in a rapidly rotating cylinder forced by the harmonic oscillations of a small sphere along the rotation axis is explored numerically. For oscillation frequencies less than twice the cylinder rotation frequency, the forced response flows feature conical shear layers emitted from the critical latitudes of the sphere. These latitudes are where the characteristics of the hyperbolic system, arrived at by ignoring nonlinear, viscous and forcing terms in the governing equations, are tangential to the sphere. These conical shear layers vary continuously with the forcing frequency so long as it remains inertial. At certain values of the forcing frequency, linear inviscid inertial modes of the cylinder are resonated. Of all possible inertial modes, only those whose symmetries are compatible with the symmetry of the forced system are resonated. This all occurs even in the linear limit of vanishingly small forcing amplitude. As the forcing amplitude is increased, nonlinearity leads to non-harmonic oscillations and a non-zero mean flow which features a Taylor columnar structure extending from the sphere to the two endwalls in an axially invariant fashion.</p
Extension of a static into a semi-dynamic traffic assignment model with strict capacity constraints
Get PDFTo improve the accuracy of large-scale strategic transport models in congested conditions, this paper presents a straightforward extension of a static capacity-constrained traffic assignment model into a semi-dynamic version. The semi-dynamic model is more accurate than its static counterpart as it relaxes the empty network assumption, but, unlike its dynamic counterpart, maintains the stability and scalability properties required for application in large-scale strategic transport model systems. Applications show that, contrary to static models, semi-dynamic queue sizes and delays are very similar to dynamic outcomes, whereas only the congestion patterns differ due to the omission of spillback. The static and semi-dynamic models are able to reach user equilibrium conditions, whereas the dynamic model cannot. On a real-world transport model, the static model omits up to 76% of collective losses. It is therefore very likely that the empty network assumption influences (policy) decisions based on static model outcomes