Learning through play: an educational computer game to introduce radar fundamentals

The information exchange has evolved from traditional books to computers and Internet in a few years' time. Our current university students were born in this age: they learn and have fun with different methods as previous generations did. These digital natives enjoy computer games. Thus, designing games for learning some selected topics could be a good teaching strategy for such collective and also for undergraduate university students. This paper describes the development and test of an educational computer game revolving around radar. The objective of the game RADAR Technology is to teach students about the fundamentals of radar, while having fun during the learning experience. Based on the principle that you learn better what you practice, the authors want to induce students to discover a difficult to understand topic by proposing them a different experience, in a format better adapted to their generation skills. The computer game has been tested with actual students and the obtained results seem to be very promising

Wideband performance comparison between the 40 GHz and 60 GHz frequency bands for indoor radio channels

When 5G networks are to be deployed, the usability of millimeter-wave frequency allocations seems to be left out of the debate. However, there is an open question regarding the advantages and disadvantages of the main candidates for this allocation: The use of the licensed spectrum near 40 GHz or the unlicensed band at 60 GHz. Both bands may be adequate for high performance radio communication systems, and this paper provides insight into such alternatives. A large measurement campaign supplied enough data to analyze and to evaluate the network performance for both frequency bands in different types of indoor environments: Both large rooms and narrow corridors, and both line of sight and obstructed line of sight conditions. As a result of such a campaign and after a deep analysis in terms of wideband parameters, the radio channel usability is analyzed with numerical data regarding its performance

Non specular reflection and depolarisation due to walls under oblique incidence

Non

RMS delay spread vs. coherence bandwidth from 5G indoor radio channel measurements at 3.5 GHz band

Our society has become fully submersed in fourth generation (4G) technologies, setting constant connectivity as the norm. Together with self-driving cars, augmented reality, and upcoming technologies, the new generation of Internet of Things (IoT) devices is pushing the development of fifth generation (5G) communication systems. In 5G architecture, increased capacity, improved data rate, and decreased latency are the objectives. In this paper, a measurement campaign is proposed; we focused on studying the propagation properties of microwaves at a center frequency of 3.5 GHz, commonly used in 5G cellular networks. Wideband measurement data were gathered at various indoor environments with different dimensions and characteristics. A ray-tracing analysis showed that the power spectrum is dominated by the line of sight component together with reflections on two sidewalls, indicating the practical applicability of our results. Two wideband parameters, root mean square delay spread and coherence bandwidth, were estimated for the considered scenarios, and we found that they are highly dependent on the physical dimension of the environment rather than on furniture present in the room. The relationship between both parameters was also investigated to provide support to network planners when obtaining the bandwidth from the delay spread, easily computed by a ray-tracing tool

Indoor path loss variations with frequency and visibility conditions at 3.5 GHz band

Studying the radio wave propagation within indoor environment is necessary previously to deploy wireless networks. Thus, and next to launching 5G systems at 3.5 GHz band, some insights on the behavior of the channel are required. This contribution describes the results of a measurement campaign in three different indoor scenarios, which are representative for a collection of similar environments. A simple path loss exponential decay model, adjusted by the measurement outcomes, indicates the evolution of radio waves as a function of the distance to the transmitter. In line of sight conditions, path loss seems to be just a bit stronger than in open space situations (the exponent is between 2 and 2.5, depending on the frequency, compared to the standard value 2 of open spaces). However, obstructed line of sight condition strengthens this decay rhythm, being over 4

Optically transparent frequency selective surface for ultrawideband applications

A multilayer ultra-wideband frequency selective surface (FSS), which filters the frequency range between 3.38 and 4.66GHz is presented. The proposed structure having a transparent substrate allows the light pass through itself, while it filters the electromagnetic waves at the frequency band of interest; and it has a bandwidth of 1.28 GHz. For the FSS structure, a transparency level of 52.5% obtained with a fractional bandwidth value of 32%. The structure is examined layer by layer; and the proposed FSS structures are evaluated in terms of bandwidth and transparency level

Item level characterization of mm-wave indoor propagation

According to the current prospect of allocating next generation wireless systems in the underutilized millimeter frequency bands, a thorough characterization of mm-wave propagation represents a pressing necessity. In this work, an “item level” characterization of radiowave propagation at 70 GHz is carried out. The scattering properties of several, different objects commonly present in indoor environment are investigated by means of measurements carried out in an anechoic chamber. The measured data have been also exploited to tune some parameters of a 3D ray tracing model

Effectiveness of rotavirus vaccination in Spain

With the aim of determining rotavirus vaccine effectiveness (RVVE) in Spain, from Oct-2008/Jun-2009, 467 consecutive children below 2 years old with acute gastroenteritis (AGE) were recruited using a pediatric research network (ReGALIP-www.regalip.org) that includes primary, emergency and hospital care settings. Of 467 enrolled children, 32.3% were rotavirus positive and 35.0% had received at least one dose of any rotavirus vaccine. RRVE to prevent any episode of rotavirus AGE was 91.5% (95% CI: 83.7%-95.6%). RVVE to prevent hospitalization by rotavirus AGE was 95.6% (85.6-98.6%). No differences in RVVE were found regarding the vaccine used. Rotavirus vaccines have showed an outstanding effectiveness in Spain

Urban hedges: a review of plant species and cultivars for ecosystem service delivery in north-west Europe

Urban hedges provide a number of important ecosystem services (ESs) including microclimate alteration, flood and pollution mitigation, and biodiversity provision, along with some disservices (DSs, e.g. invasiveness, allergenicity). However, hedge plant species differ in their capacity to promote different services, so it is important that the decision to plant hedges is evidence-based. The objectives of this study were thus to (i) to review the role of urban hedges within NW Europe; (ii) review the available literature detailing the ESs and DSs provided by different plant species and cultivars when used as hedge plants; (iii) identify where there is a lack of evidence for certain species or ESs/DSs; and (iv) develop a starting point for a discussion about appropriate species/cultivar selection to deliver multiple ESs, and avoid DSs. Many studies consider biodiversity and air quality ESs. There are significant gaps in the literature relating to rainfall mitigation/flood protection, but also CO2 sequestration, allergenicity and human psychological well-being impact of different species. Additionally, for noise and pollution mitigation studies, a range of methodologies and units are used, making comparisons between hedge species difficult/impossible. A number of common hedge species demonstrated high levels of ESs delivery, including Fagus sylvatica, Crataegus monogyna, Ilex aquifolium and Rosa rugosa. No species surveyed had an entirely negative association with ESs, and most provide at least some benefits in supporting ESs provision (e.g. Viburnum tinus, Laurus nobilis). We created a matrix, in a table form, linking plant species, key plant traits and ESs/DSs, which should make it easier for professionals to choose species best suited to provide multiple benefits, whilst minimising the drawbacks. Our review suggests that the relative contribution of urban hedges to ESs delivery may be under-valued currently, and calls for more research