145 research outputs found
On Target Detection by Quantum Radar (Preprint)
Both Noise Radar and Quantum Radar, with some alleged common features,
exploit the randomness of the transmitted signal to enhance radar covertness
and to reduce mutual interference. While Noise Radar has been prototypically
developed and successfully tested in many environments by different
organizations, the significant investments on Quantum Radar seem not to be
followed by practically operating prototypes or demonstrators. Starting from
the trivial fact that radar detection depends on the energy transmitted on the
target and backscattered by it, some detailed evaluations in this work show
that the detection performance of all the proposed QR types in the literature
are orders of magnitude below the ones of a much simpler and cheaper equivalent
classica radar set, in particular of the NR type. Moreover, the absence of a,
sometimes alleged, Quantum radar cross section different from the radar cross
section is explained. Hence, the various Quantum Radar proposals cannot lead to
any useful result, especially, but not limited to, the alleged detection of
stealth targets.Comment: 12 pages, 6 figures, 11 equations, 62 References. Not submitted. A
"negative" result is obtained and presented with full details. This resuly is
deemed useful and interesting according to the teachings by Karl Poppe
Range limitations in microwave quantum radar
This work, written for engineers or managers with no special knowledge of quantum mechanics, nor deep experience in radar, aims to help the scientific, industrial, and governmental community to better understand the basic limitations of proposed microwave quantum radar (QR) technologies and systems. Detection and ranging capabilities for QR are critically discussed and a comparison with its closest classical radar (CR), i.e., the noise radar (NR), is presented. In particular, it is investigated whether a future fielded and operating QR system might really outperform an âequivalentâ classical radar, or not. The main result of this work, coherently with the recent literature, is that the maximum range of a QR for typical aircraft targets is intrinsically limited to less than one km, and in most cases to some tens of meters. Detailed computations show that the detection performance of all the proposed QR types are orders of magnitude below the ones of any much simpler and cheaper equivalent âclassicalâ radar set, in particular of the noise radar type. These limitations do not apply to very-short-range microwave applications, such as microwave tomography and radar monitoring of heart and breathing activity of people (where other figures, such as cost, size, weight, and power, shall be taken into account). Moreover, quantum sensing at much higher frequencies (optical and beyond) is not considered here
On the antiâintercept features of noise radars
Robustness against Electronic Warfare/Electronic Defence attacks represents an
important advantage of Noise Radar Technology (NRT). An evaluation of the related
Low Probability of Detection (LPD) and of Intercept (LPI) is presented for Continuous
Emission Noise Radar (CEâNR) waveforms with different operational parameters, that is,
âtailoredâ, and with various âdegrees of randomnessâ. In this frame, three different noise
radar waveforms, a phase Noise (APCN) and two âtailoredâ noise waveforms (FMeth
and COSPAR), are compared by timeâfrequency analysis. Using a correlator (i.e. a two
antennas) receiver, assuming a complete knowledge of the band (B) and duration (T) of
the coherent emission of these waveforms, it will be shown that the LPD features of a
CEâNR do not significantly differ from those of any CE radar transmitting deterministic
waveforms. However, in real operations, B and T are unknown; hence, assuming an
instantaneous bandwidth estimation will show that the duration T can be estimated only
for some specific âtailoredâ waveforms (of course, not to be operationally used). The
effect of âtailoringâ is analysed with prospects for future work. Finally, some limitations
in the classification of these radar signals are analysed
Waveform Design and Related Processing for Multiple Target Detection and Resolution
The performance of modern radar systems mostly depends on the radiated waveforms, whose design is the basis of the entire system design. Todayâs coherent, solid-state radars (either of the phased array type or of the single-radiator type as air traffic control or marine radars) transmit a set of deterministic signals with relatively large duty cycles, an order of 10%, calling for pulse compression to get the required range resolution. Often, power budget calls for different pulse lengths (e.g., short, medium, and long waveforms with a rectangular envelope) to cover the whole radar range. The first part of the chapter includes the topic of mitigating the effect of unwanted side lobes, inherent to every pulse compression, which is achieved both by a careful and optimal design of the waveform and by a (possibly mismatched) suitable processing. The second part of the chapter deals with the novel noise radar technology, not yet used in commercial radar sets but promising: (1) to prevent radar interception and exploitation by an enemy part and (2) to limit the mutual interferences of nearby radars, as in the marine environment. In this case, the design includes a tailoring of a set of pseudo-random waveforms, generally by recursive processing, to comply with the system requirements
Signal design and processing for noise radar
An efficient and secure use of the electromagnetic spectrum by different telecommunications
and radar systems represents, today, a focal research point, as the coexistence
of different radio-frequency sources at the same time and in the same frequency band
requires the solution of a non-trivial interference problem. Normally, this is addressed
with diversity in frequency, space, time, polarization, or code. In some radar applications,
a secure use of the spectrum calls for the design of a set of transmitted waveforms
highly resilient to interception and exploitation, i.e., with low probability of intercept/
exploitation capability. In this frame, the noise radar technology (NRT) transmits
noise-like waveforms and uses correlation processing of radar echoes for their optimal
reception. After a review of the NRT as developed in the last decades, the aim of this
paper is to show that NRT can represent a valid solution to the aforesaid problems
Investment Grade Energy Audit: A Financial Tool for the Cost-effective Renovation of Residential Buildings
The renovation of the existing building stock is a top priority for the European Union. In order to reach the ambitious goal of decarbonization by 2050, new financial instruments, incentives or grants and loans to support energy efficiency should be implemented, especially for public bodies. The proposed method aims to be a tool to stimulate cost-effective deep renovations. The results of its application to a multi-owner building show the benefits of using Energy Service Companies and Energy Performance Contracting to finance renovations and implement plans to maintain or improve energy efficiency in the long term
Extreme precipitation events over northern Italy. Part I: A systematic classification with machineâlearning techniques
Extreme precipitation events (EPEs) are meteorological phenomena of major concern for society. They can have different characteristics depending on the physical mechanisms responsible for their generation, which in turn depend on the large and mesoscale conditions. This work provides a systematic classification of EPEs over northernâcentral Italy, one of the regions in Europe with the highest frequency of these events. The EPE statistics have been deduced using the new highâresolution precipitation dataset ArCIS (Climatological Archive for CentralâNorthern Italy), that gathers together a very high number of daily, qualityâcontrolled and homogenized observations from different networks of 11 Italian regions. Gridded precipitation is aggregated over Italian operational warningâarea units (WA). EPEs are defined as events in which daily average precipitation in at least one of the 94 WAs exceeds the 99th percentile with respect to the climate reference 1979â2015. A list of 887 events is compiled, significantly enlarging the database compared to any previous study of EPEs. EPEs are separated into three different dynamical classes: Cat1, events mainly attributable to frontal/orographic uplift; Cat2, events due to frontal uplift with (equilibrium) deep convection embedded; Cat3, events mainly generated by nonâequilibrium deep convection. A preliminary version of this classification is based on fixed thresholds of environmental parameters, but the final version is obtained using a more robust machineâlearning unsupervised Kâmeans clustering and random forest algorithm. All events are characterized by anomalously high integrated water vapour transport (IVT). This confirms IVT as an important largeâscale predictor, especially for Cat2 events, which is shown to be the most important category in terms of impacts and EPE area extension. Large IVT values are caused by upperâlevel waves associated with remotely triggered Rossby wave packets, as shown for two example Cat2 events
Impacts of climate change and rising atmospheric CO2 on future projected reference evapotranspiration in Emilia-Romagna (Italy)
The continuous increase of atmospheric CO2 content mainly due to anthropogenic CO2 emissions is causing a rise in temperature on earth, altering the hydrological and meteorological processes and affecting crop physiology. Evapotranspiration is an important component of the hydrological cycle. Thus, understanding the change in evapotranspiration due to global warming is essential for better water resources planning and management and agricultural production. In this study, the effect of climate change with a focus on the combined effect of temperature and elevated CO2 concentrations on reference evapotranspiration (ETo) was evaluated using the PenmanâMonteith equation. A EURO-CORDEX regional climate model (RCM) ensemble was used to estimate ETo in five locations in the Emilia-Romagna region (Northern Italy) during the period 2021â2050. Then, its projected changes in response to different CO2 concentrations (i.e., 372 ppm and 550 ppm) under two Representative Concentration Pathways (RCP) scenarios (i.e., RCP4.5 and RCP8.5) were analyzed. Simulation results with both scenarios, without increasing CO2 levels (372 ppm), showed that the annual and summertime ETo for all locations increased by an average of 4 to 5.4% with regard to the reference period 1981â2005, for an increase of air temperature by 1 to 1.5 °C. When the effect of elevated CO2 levels (550 ppm) was also considered in combination with projected changes in temperature, changes in both annual and summer ETo demand for all locations varied fromâââ1.1 to 2.2% during the 2021â2050 period with regard to the reference period 1981â2005. This shows that higher CO2 levels moderated the increase in ETo that accompanies an increase in air temperature
A conservative treatment for eosinophilic cystitis
Introduction: Eosinophilic cystitis is a rare condition which causes common symptoms and may mimic other conditions. Eosinophilic cystitis has several causes such as hypereosinophilic syndrome, inflammatory diseases, neoplasia, parasites or fungal infection, IgE-related diseases, Drug Reaction and Eosinophilia and Systemic Symptoms (DRESS) syndrome, or Churg-Strauss syndrome. Therefore, differential diagnosis is difficult. Case presentation: We report the case of a middle-aged man affected by eosinophilic cystitis with persistent hematuria and other peculiar symptoms that may be brought back to hypereosinophilic crisis. Conclusion: Conservative approach is preferred, avoiding radical cystectomy rather than corticosteroid, antihistaminic and second line therapy. Hyperbaric therapy is an innovative approach for severe relapsing gross hematuria without specific literature and should be studied for further indications
Analysis of Bacterial Stent Colonization: The Role of Urine and Device Microbiological Cultures
In this study, we explored the incidence of double J (JJ) contamination of patients who underwent an endourological procedure for urinary stones and ureteral stenosis. We developed a prospective study between January 2019 and December 2021. Ninety-seven patients, 54 male and 43 female, were enrolled. Urine culture was taken during four steps: before stent insertion, a sample from selective renal pelvis catheterization, a sample two days after the JJ insertion and finally, after the stent removal procedure. At the time of the stent removal, 1 cm of proximal and distal ends were cut off and placed in the culture for bacterial evaluation. Cohen's kappa coefficient value (k) and concordance rates of microbiological culture results were evaluated. The study group comprised 56% of male patients. Proximal and distal stent cultures were positive in 81 and 78 patients. The concordance rate of microbiological cultures between proximal and distal double J stent is 88% (k 0.6). The most common pathogens isolated from urine and stent cultures were Enterococcus spp. in 52 cases and Klebsiella spp. in 27 cases
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