Empowering citizen scientists: a hidden dance between the ivory tower of science and lay people

This work revolves around the relation between scientists and lay people in the domain of Citizen Science (CS). In the first part, \u2018Context and research question\u2019, it presents a logical collection of relevant key concepts: origin of the term CS; clarification of the meaning of \u2018citizen\u2019 and \u2018scientist\u2019 used in the text; PUS and PES interpretations of public participation in Science; government interests and efforts in developing CS; risk of presence of the deficit model; some classifications of CS projects and epistemic practices; post-normal science approach to society and empowerment of citizens. The last section of this part is dedicated to pose the research question: \u2018How is Citizen Science perceived by scientists of the scientific community?\u2019. In the second part, \u2018Conclusions\u2019, some concepts are presented and developed as results: existence of a polarization between scientists inside and outside the ivory tower of science; perception of data quality, objectivity of CS research and peer judgement; authorship and pay of citizen scientists; inevitable growth of CS both for scientific projects and for the bottom-up empowerment of citizens. The work also presents the \u2018affiliation principle\u2019 and suggests how a definition of scientist, detached from this principle, could apply to lay people, that is to a broader group of individuals than that of the ivory tower of science

A comparison between two pneumatic suspension architectures

The aim of this work is to assess and compare the mathematical models of two pneumatic suspension architectures and show how they can converge, after appropriate simplifications, to a general linear form. After making this model dimensionless, it will be used to study, with a transmissibility analysis, the behaviour of a mono-suspension (quarter-car model). Finally, an example of a design process will be shown to highlight the strengths and weaknesses of both architectures and to provide the reader with a practical design too

Evolution of Monolithic Technology for Wireless Communications: GaN MMIC Power Amplifiers For Microwave Radios

This paper presents the progress of monolithic technology for microwaveapplication, focusing on gallium nitride technology advances in the realization of integratedpower amplifiers. Three design examples, developed for microwave backhaul radios, areshown. The first design is a 7 GHz Doherty developed with a research foundry, while thesecond and the third are a 7 GHz Doherty and a 7–15 GHz dual-band combined poweramplifiers, both based on a commercial foundry process. The employed architectures, themain design steps and the pros and cons of using gallium nitride technology are highlighted.The measured performance demonstrates the potentialities of the employed technology, andthe progress in the accuracy, reliability and performance of the process

Behavioral modeling of GaN-based power amplifiers: impact of electrothermal feedback on the model accuracy and identification

In this article, we discuss the accuracy of behavioral models in simulating the intermodulation distortion (IMD) of microwave GaN-based high-power amplifiers in the presence of strong electrothermal (ET) feedback. Exploiting an accurate self-consistent ET model derived from measurements and thermal finite-element method simulations, we show that behavioral models are able to yield accurate results, provided that the model identification is carried out with signals with wide bandwidth and large dynamics

COREC: Concurrent Non-Blocking Single-Queue Receive Driver for Low Latency Networking

Existing network stacks tackle performance and scalability aspects by relying on multiple receive queues. However, at software level, each queue is processed by a single thread, which prevents simultaneous work on the same queue and limits performance in terms of tail latency. To overcome this limitation, we introduce COREC, the first software implementation of a concurrent non-blocking single-queue receive driver. By sharing a single queue among multiple threads, workload distribution is improved, leading to a work-conserving policy for network stacks. On the technical side, instead of relying on traditional critical sections - which would sequentialize the operations by threads - COREC coordinates the threads that concurrently access the same receive queue in non-blocking manner via atomic machine instructions from the Read-Modify-Write (RMW) class. These instructions allow threads to access and update memory locations atomically, based on specific conditions, such as the matching of a target value selected by the thread. Also, they enable making any update globally visible in the memory hierarchy, bypassing interference on memory consistency caused by the CPU store buffers. Extensive evaluation results demonstrate that the possible additional reordering, which our approach may occasionally cause, is non-critical and has minimal impact on performance, even in the worst-case scenario of a single large TCP flow, with performance impairments accounting to at most 2-3 percent. Conversely, substantial latency gains are achieved when handling UDP traffic, real-world traffic mix, and multiple shorter TCP flows

GaN Monolithic Power Amplifiers for Microwave Backhaul Applications

Gallium nitride integrated technology is very promising not only for wireless applications at mobile frequencies (below 6 GHz) but also for network backhaul radiolink deployment, now under deep revision for the incoming 5G generation of mobile communications. This contribution presents three linear power amplifiers realized on 0.25 μ m Gallium Nitride on Silicon Carbide monolithic integrated circuits for microwave backhaul applications: two combined power amplifiers working in the backhaul band around 7 GHz, and a more challenging third one working in the higher 15 GHz band. Architectures and main design steps are described, highlighting the pros and cons of Gallium Nitride with respect to the reference technology which, for these applications, is represented by gallium arsenide

High efficiency power amplifiers for modern mobile communications: The load-modulation approach

Modern mobile communication signals require power amplifiers able to maintain very high efficiency in a wide range of output power levels, which is a major issue for classical power amplifier architectures. Following the load-modulation approach, efficiency enhancement is achieved by dynamically changing the amplifier load impedance as a function of the input power. In this paper, a review of the widely-adopted Doherty power amplifier and of the other load-modulation efficiency enhancement techniques is presented. The main theoretical aspects behind each method are introduced, and the most relevant practical implementations available in recent literature are reported and discussed

Design of a 87% fractional bandwidth Doherty Power Amplifier supported by a simplified bandwidth estimation method

This paper presents a novel technique for the design of broadband Doherty power amplifiers (DPAs), supported by a simplified approach for the initial bandwidth estimation that requires linear simulations only. The equivalent impedance of the Doherty inverter is determined by the value of the output capacitance of the power device, and the Doherty combiner is designed following this initial choice and using a microstrip network. A GaN-based single-input DPA designed adopting this method exhibits, on a state-of-the-art bandwidth of 87% (1.5-3.8 GHz), a measured output power of around 20 W with 6 dB back-off efficiency between 33% and 55%, with a gain higher than 10 dB. System-level measurements prove the linearizability of the designed Doherty amplifier when a modulated signal is applied

13-bit GaAs serial-to-parallel converter with compact layout for core-chip applications

Design and characterization of a 13 bit serial-to-parallel converter in GaAs technology for smart antennas are presented. The circuit has been realized with NOR-based super-buffered enhancement/depletion logic, and optimized for a compact layout. The serial-to-parallel converter operates properly well above the 20 kHz design clock frequenc

Metronome: Adaptive and Precise Intermittent Packet Retrieval in DPDK

The increasing performance requirements of modern applications place a significant burden on software-based packet processing. Most of today’s software input/output accelerations achieve high performance at the expense of reserving CPU resources dedicated to continuously poll the Network Interface Card. This is specifically the case with DPDK (Data Plane Development Kit), probably the most widely used framework for software-based packet processing today. The approach presented in this paper, descriptively called Metronome, has the dual goals of providing CPU utilization proportional to the load, and allowing flexible sharing of CPU resources between I/O tasks and applications. Metronome replaces DPDK’s continuous polling with an intermittent sleep&wake mode, and revolves around a new multi-threaded operation, which improves service continuity. Since the proposed operation trades CPU usage with buffering delay, we propose an analytical model devised to dynamically adapt the sleep&wake parameters to the actual traffic load, meanwhile providing a target average latency. Our experimental results show a significant reduction of the CPU cycles, improvements in power usage, and robustness to CPU sharing even when challenged with CPU-intensive applications