15 research outputs found
Cross cancellation technique employing an error amplifier [Letter]
In this letter, we propose a new distortion cancellation
mechanism for a balanced power amplifier (PA) structure using
the cross cancellation technique employing an error amplifier. The
proposed cross cancellation balanced linear PA is implemented in
the IMT-2000 ( 0 = 2.14 GHz) band. With commercial PAs with
a peak power of 240 W for base-station application, the proposed
system shows 18.6 dB improvement at an average output power
of 40 dBm for adjacent channel leakage ratio measurement with
wideband code division multiple access 4FA signal. The efficiency
of the proposed structure is about 2% higher than the conventional
feedforward amplifier for modulated carrier
Unmanned Aircraft Systems in the Cyber Domain
Unmanned Aircraft Systems are an integral part of the US national critical infrastructure. The authors have endeavored to bring a breadth and quality of information to the reader that is unparalleled in the unclassified sphere. This textbook will fully immerse and engage the reader / student in the cyber-security considerations of this rapidly emerging technology that we know as unmanned aircraft systems (UAS). The first edition topics covered National Airspace (NAS) policy issues, information security (INFOSEC), UAS vulnerabilities in key systems (Sense and Avoid / SCADA), navigation and collision avoidance systems, stealth design, intelligence, surveillance and reconnaissance (ISR) platforms; weapons systems security; electronic warfare considerations; data-links, jamming, operational vulnerabilities and still-emerging political scenarios that affect US military / commercial decisions.
This second edition discusses state-of-the-art technology issues facing US UAS designers. It focuses on counter unmanned aircraft systems (C-UAS) – especially research designed to mitigate and terminate threats by SWARMS. Topics include high-altitude platforms (HAPS) for wireless communications; C-UAS and large scale threats; acoustic countermeasures against SWARMS and building an Identify Friend or Foe (IFF) acoustic library; updates to the legal / regulatory landscape; UAS proliferation along the Chinese New Silk Road Sea / Land routes; and ethics in this new age of autonomous systems and artificial intelligence (AI).https://newprairiepress.org/ebooks/1027/thumbnail.jp
EUROSENSORS XVII : book of abstracts
Fundação Calouste Gulbenkien (FCG).Fundação para a Ciência e a Tecnologia (FCT)
Air Traffic Management Abbreviation Compendium
As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages.
In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation
GSI Scientific Report 2016
PLEASE GO TO FILES TO SELECT YOUR DOWNLOAD SECTION. Lience: https://creativecommons.org/licenses/by/4.0
Recommended from our members
Muscle activation patterns in shoulder impingement patients
Introduction: Shoulder impingement is one of the most common presentations of shoulder joint problems 1. It appears to be caused by a reduction in the sub-acromial space as the humerus abducts between 60o -120o – the 'painful arc'. Structures between the humeral head and the acromion are thus pinched causing pain and further pathology 2. Shoulder muscle activity can influence this joint space but it is unclear whether this is a cause or effect in impingement patients. This study aimed to observe muscle activation patterns in normal and impingement shoulder patients and determine if there were any significant differences.
Method: 19 adult subjects were asked to perform shoulder abduction in their symptomatic arm and non-symptomatic. 10 of these subjects (age 47.9 ± 11.2) were screened for shoulder impingement, and 9 subjects (age 38.9 ± 14.3) had no history of shoulder pathology. Surface EMG was used to collect data for 6 shoulder muscles (Upper, middle and lower trapezius, serratus anterior, infraspinatus, middle deltoids) which was then filtered and fully rectified. Subjects performed 3 smooth unilateral abduction movements at a cadence of 16 beats of a metronome set at 60bpm, and the mean of their results was recorded. T-tests were used to indicate any statistical significance in the data sets. Significance was set at P<0.05.
Results: There was a significant difference in muscle activation with serratus anterior in particular showing a very low level of activation throughout the range when compared to normal shoulder activation patterns (<30%). Middle deltoid recruitment was significantly reduced between 60-90o in the impingement group (30:58%).Trends were noted in other muscles with upper trapezius and infraspinatus activating more rapidly and erratically (63:25%; 60:27% respectively), and lower trapezius with less recruitment (13:30%) in the patient group, although these did not quite reach significance.
Conclusion: There appears to be some interesting alterations in muscle recruitment patterns in impingement shoulder patients when compared against their own unaffected shoulders and the control group. In particular changes in scapula control (serratus anterior and trapezius) and lateral rotation (infraspinatus), which have direct influence on the sub-acromial space, should be noted. It is still not clear whether these alterations are causative or reactionary, but this finding gives a clear indication to the importance of addressing muscle reeducation as part of a rehabilitation programme in shoulder impingement patients
Recommended from our members
The translational potential of sleep and circadian rhythm disturbances as a biomarker of Alzheimer's disease
Highlights CNR 2009-2010
The 2009-2010 edition of CNR.it (the CNR Highlights) includes more than 200 scientific papers. Conceived and written in
English to present to the international public the dynamic and multi-sided reality of the largest research organization in
Italy, this review is a partial but significant collection of works carried out by CNR researchers and published on the main
scientific journals. Articles have been selected on the basis of their impact factors among the 14.000 or so articles produced
in the last two years, to present our best image to the world.
The present one is only the second of the CNR Highlights, after a first one dedicated to the Italian public, but the series
represent already a must for our researchers, to promote their works along best-practice lines followed in research organizations
worldwide.
In the present edition, with a more catchy new look, articles, images and scientific popularizations provide a broad outlook
of the activities of CNR, reporting, side by side with research articles, about technology transfer and scientific support activities
to national and local institutions.
The 2009-2010 Highlights are divided into four sections, similarly to the previous edition. However, as the reader looks
through the pages, the interdisciplinary nature of the works will not pass unnoticed, interdisciplinarity being the peculiar
feature of CNR, an organization in which the different disciplines find a fertile breeding ground to communicate and share
their different knowledge