Unreferenced date December 2009 A highfrequencyapproximation or high energy approximation for scattering or other wave propagation problems, in physics or engineering , is an approximation whose accuracy increases with the size of features on the scatterer or medium relative to the wavelength of the scattered particles. Classical mechanics and geometric optics are the most common and extreme highfrequencyapproximation, where the wave or field properties of, respectively, quantum mechanics and electromagnetism are neglected entirely. Less extreme approximations include, the WKB approximation , physical optics , the geometric theory of diffraction , the uniform theory of diffraction , and the physical theory of diffraction . When these are used to approximate quantum mechanics , they are called semiclassical approximations. See also Electromagnetic modeling DEFAULTSORT HighFrequencyApproximation Category Scattering Category Scattering, absorption and radiative transfer optics ... more details
MWband freq 3 to 30 megahertz MHz bands Highfrequency HF radio frequency radio frequencies are between ... MUF Lowest usable highfrequency LUF and a Frequency of optimum transmission FOT The maximum usable ... in full summer the higher frequencies tend to be more usable, often into the lower Very highfrequency ... two HF transceivers. The highfrequency band is very popular with amateur radio operators, who can take ... STD 188 141 for automated connectivity and frequency selection, along with the high costs of satellite ... HF. These tags are commonly known as HFID s or HighFID s HighFrequency Identification . See also HighFrequency Active Auroral Research Program HighFrequency Internet Protocol Low frequency Radio ... Transmission of HighFrequency Phonons by a Superlattice The Dielectric Phonon Filter . Phys ... Depression Induced by HighFrequency Deep Brain Stimulation . New England Journal of Medicine, Volume ... of highfrequency resonant tunneling The first order ac current response . Phys. Rev. B 43, 12538 12548 Issue 15 15 May 1991 . Sipila, M., et al., Highfrequency periodic time domain waveform measurement ..., Oct 1988. ISSN 0018 9480 INSPEC 3291255 DOI 10.1109 22.6087 Morched, A., et al., A highfrequency ... vlf.it . Douglas C. Smith, http www.emcesd.com HighFrequency Measurements Web Page Index and Technical ... Frequency Propagation Models , its.bldrdoc.gov. http www.cscamm.umd.edu programs hfw05 HighFrequency ... 345.pdf Grounding for Low and HighFrequency Circuits PDF http www.mrec.org pubs HighFrequencyNoise InformationalPage 05.pdf Highfrequency noise PDF http www.codan.com.au HFRadio WhyHF ... HF id Frekuensi tinggi it Highfrequency he Highfrequency nl Highfrequency ja ... Medium frequency Medium frequency MF , and the next higher frequencies are known as VHF Very highfrequency VHF . The Shortwave range 2.310 25.820 MHz used by international broadcasters is part of the HF frequency spectrum. In aviation virtually the entire spectrum 2 29.999 MHz is used ... more details
The lowest usable highfrequency LUF , in radio transmission telecommunications transmission , is that frequency in the Highfrequency HF band at which the received field intensity is sufficient to provide the required signal to noise ratio for a specified time period, e.g., 0100 to 0200 UTC, on 90 of the undisturbed days of the month. The amount of energy absorbed by the lower regions of the ionosphere D region, primarily directly impacts the LUF. See also Maximum usable frequencyFrequency of optimum transmission Source Federal Standard 1037C Category Radio frequency propagation telecomm stub de Lowest Usable Frequency ... more details
MWband freq 3 to 30 gigahertz GHz bands Super highfrequency or SHF refers to radio frequency radio frequencies RF in the range of 3 Hertz GHz and 30 GHz. This band of frequencies is also known as the centimetre band or centimetre wave as the wavelengths range from ten to one centimetres. Description The International Telecommunication Union ITU , an international civil organization established to standardized worldwide telecommunication s, have stated that the superhigh frequency is encountered between 100 mm to 10 mm. Super highfrequency electromagnetic waves are relatively short for radio waves . This frequency is used for microwave devices, Wireless LAN WLAN , most modern radar s. The commencing Wireless USB technology will be using approximately 1 3 of this spectrum. Uses Some uses are IEEE 802.11a wireless LANs, satellite uplinks downlinks, and terrestrial high speed data links, such as cellular telephone Backhaul telecommunications backhauls . See also Knife edge effect Microwave External links Tomislav Stimac, http www.vlf.it frequency bands.html Definition of frequency bands VLF, ELF... etc. . IK1QFK Home Page vlf.it . In s Vidal Casti eira, http www.broadbandhomecentral.com report backissues Report0308 3.html Celeria Wireless Access To Cable Networks radio spectrum Telecommunications EMSpectrum telecomm stub Category Radio spectrum Category Wireless ar ca SHF cv da SHF de Zentimeterwelle es SHF eo Centimetra ondo fa fr Supra haute fr quence hi SHF it Super highfrequency nl Super highfrequency ne SHF ja no Superh y frekvens pl Fale centymetrowe ru fi Super highfrequency sv SHF frekvensband zh ... more details
Interventions infobox Name Highfrequency ventilation Image Caption ICD10 ICD9unlinked MeshID D006612 OPS301 OtherCodes Highfrequency ventilation is a type of mechanical ventilation that employs very ... cite journal author Krishnan JA, Brower RG title Highfrequency ventilation for acute lung injury ... TJ, Morganroth ML. Highfrequency ventilation. Chest 1989 96 1380. ref Highfrequency ventilation ... Bollen CW, Uiterwaal CS, van Vught AJ. Systematic review of determinants of mortality in highfrequency ... flavors of Highfrequency ventilation . ref name krishan Each type has its own unique ... of exhalation phase. HighFrequency Ventilation may be used alone, or in combination with conventional .... Specifications and capabilities will vary depending on the device manufacturer. HighFrequency Ventilation Passive HighFrequency Jet Ventilation File Inhaled Nitric Oxide iNO Delivery with Highfrequency Jet Ventilation HFJV .jpg thumb Inhaled Nitric Oxide iNO Delivery with Highfrequency Jet Ventilation Highfrequency jet ventilation HFJV is provided by the Bunnell Life Pulse HighFrequency Ventilator ... for a very brief duration, about 0.02 seconds, and at highfrequency 4 11 hertz. Tidal volumes 1 ml ... . Usage of highfrequency jet ventilation is recommended in neonates and adults with severe lung ... , M. Klain & J. V. Snyder title Comparison of highfrequency jet ventilation to conventional ventilation ... Pulse HighFrequency Ventilator is indicated for use in ventilating critically ill infants with pulmonary ... and in gestation age from 24 to 41 weeks. The Bunnell Life Pulse HighFrequency Ventilator is also indicated ... of highfrequency ventilation include those commonly found during the use of conventional positive pressure ... Bronchopulmonary dysplasia Contraindications Highfrequency jet ventilation is contraindicated ... s lungs, as well as loss of lung volume due to tension pneumothorax . HighFrequency Percussive Ventilation HFPV Highfrequency percussive ventilation combines HFV plus time cycled, pressure ... more details
In signal processing , the highfrequency content measure is a simple measure, taken across a signal spectrum usually a STFT spectrum , that can be used to characterize the amount of highfrequency content in the signal. The magnitudes of the spectral bins are added together, but multiplying each magnitude by the bin position proportional to the frequency . Thus if X k is a discrete spectrum with N unique points, its highfrequency content measure is math mathrm HFC sum i 0 N 1 i X i math In contrast to perceptual measures, this is not based on any evidence about its relevance to human hearing . Despite that, it can be useful for some applications, such as onset detection . The measure has close similarities to the spectral centroid measure, being essentially the same calculation but without normalization according to overall magnitude. References P. Brossier, J. P. Bello and M. D. Plumbley. http aubio.piem.org articles brossier04realtimesegmentation.pdf Real time temporal segmentation of note objects in music signals , in Proceedings of the International Computer Music Conference ICMC 2004 , Miami, Florida, USA, November 1 6, 2004. Masri, P. 1996 . Computer modeling of Sound for Transformation and Synthesis of Musical Signal. PhD dissertation, University of Bristol. Category Digital signal processing Signal processing stub no M l p h yfrekvent innhold ... more details
Tremendously highfrequency THF is a band designation used by some authors ref cite book last Tanenbaum first Andrew title Computer Networks year 2002 publisher Prentice Hall location page 101 isbn 9780130661029 pages 912 url http books.google.com books?id Pd z64SJRBAC&pg PA101&lpg PA101&dq tremendously high frequency&source bl&ots RCMLIuV 9y&sig f1vHv6mMNmCqjjfFauDZQqADgTg&hl en&ei 8IiGTZWOAcmY0QGulaXWCA&sa X&oi book result&ct result&resnum 10&ved 0CEcQ6AEwCTgK v onepage&q tremendously 20high 20frequency&f false ref to refer to a decade band in the submillimeter radiation terahertz radiation range. It follows the ITU EHF band in increasing frequency order. dubious date April 2012 THF runs the range of frequencies from 300 gigahertz to 3 terahertz , laying in the low or far infrared range of the electromagnetic spectrum . The wavelength in this band varies from one to one tenth of a millimetre. Amateur Radio Service operators make experiments around 322 GHz, 403 GHz and 411 GHz. See also Terahertz radiation Radio spectrum References Reflist Radio spectrum DEFAULTSORT Tremendously HighFrequency Category Radio spectrum Electronics stub ... more details
HighFrequency Internet Protocol acronyms HFIP or HF IP. Usually associated with Automatic Link Establishment and HF radio data communications. HFIP provides protocol layers enabling internet file transfer, chat, web, or email. HFIP commonly uses ionosphere propagation of radio waves to form a wide area network that can span thousands of kilometers. HF transceivers in HFIP service typically run 20 to 150 Watts for portable or mobile units, up to approximately 2000 Watts transmitter output for high power base stations with HFIP servers. STANAG 5066 is a common HFIP standard. An amateur radio HFIP network called HFLINK ref cite web url http hflink.com title HFLINK accessdate 21 Sep 2010 ref uses Automatic Link Establishment for initiating data communications, with ARQ 8FSK frequency shift keying and PSK phase shift keying signals. References reflist Category Internet protocols internet stub ... more details
Globalize date April 2012 Financial market participants Highfrequency trading HFT is the use of sophisticated ... name whatis cite news author Irene Aldridge title What is HighFrequency Trading, After All? url http www.huffingtonpost.com irene aldridge what is highfrequency tr b 639203.html publisher Huffington ... a day ref http www.youtube.com watch?v FGHbddeUBuQ What is HighFrequency Trading video ref At the end ... absorbs capital from slower day trading platforms. Highfrequency trading removes any value ... title HighFrequency Traders Are Turning Markets Into A Casino url http articles.businessinsider.com ... work CounterPunch date April 23, 2010 accessdate May 8, 2010 ref . Highfrequency traders compete on a basis of speed with other highfrequency traders, not long term investors who typically look ... date April 21, 2010 accessdate September 10, 2010 ref As a result, highfrequency trading has been ... frequency trading url http www.huffingtonpost.com irene aldridge how profitable are high f b 659466.html ... just a fraction of a penny per share or currency unit on every trade, highfrequency traders move in and out ... significantly positive results at the end of every day. ref name whatis Highfrequency trading ... their entire portfolios on a daily basis. ref name secletter1 By 2010 highfrequency trading accounted ... and highfrequency trading were both found to have contributed to volatility on the May 6, 2010 Flash Crash , when highfrequency liquidity providers were in fact found to have withdrawn from ... work Reuters date July 7, 2011 accessdate July 12, 2011 ref History Highfrequency trading has taken ... highfrequency trading was a little known topic outside the financial sector, with an article published ... July 23, 2009 accessdate Sept. 10, 2010 ref Market growth In the early 2000s, highfrequency trading ... highfrequency trading might be accounted. ref name speedPays As of the first quarter in 2009, total assets under management for hedge funds with highfrequency trading strategies were 141 billion ... more details
Orphan date October 2011 Infobox company company name HighFrequency Economics, Ltd. company logo http www.hifreqecon.com images graph.gif company slogan company type Private company Private foundation 1988 location Valhalla, New York industry key people Carl B. Weinberg homepage http www.hifreqecon.com www.hifreqecon.com HighFrequency Economics, Ltd. is an economics firm founded by Carl B. Weinberg located in Valhalla, New York . ref http www.hifreqecon.com home.html HighFrequency Economics Website ref Description The firm was founded by Carl B. Weinberg , who received his B.Sc. from Rutgers University and Ph.D. from University of Pennsylvania , after he left his position as economist for Shearson Lehman Brothers . The firm produces independent analysis of the global economy and markets, in the form of daily research. ref http www.hifreqecon.com home.html Company Website ref The firm provides several products, namely daily and weekly notes on the US and global economies. In the publications, economists Dr. Carl Weinberg of New York and Dr. Ian Shepherdson of London analyze highfrequency economic data in the United States, the Euro Zone, France, Germany, the United Kingdom, Japan, China, Canada and Australia, tracking yield curve s, exchange rates, inflation and other economic indicators. ref http www.hifreqecon.com products and services.html Products and Services ref The firm does not provide investment advice rather, it provides a subscriber with economic knowledge that it believes will help the client to make day to day, and long term, financial decisions. Approximately 350 institutions subscribe to the firm s publications, especially investment management firms, hedge funds, asset management firms. Weinberg and Shepherdson have been quoted frequently by The New York Times , The Wall Street Journal , The Times and other media. History The firm was founded in 1988 ... 12 July 2011. ref References reflist External links http www.hifreqecon.com HighFrequency Economics ... more details
orphan date October 2009 Wikify date October 2009 HighFrequency Data Link HighFrequency Data Link HFDL is an ACARS communications media used to exchange data such as Aeronautical Operational Control AOC messages, Controller Pilot Data Link Communication CPDLC messages and Automatic Dependent Surveillance ADS messages between aircraft end systems and corresponding ground based HFDL ground stations. Using the unique propagation characteristics of highfrequency radio waves, the ground stations provide data link communications to properly equipped aircraft operating anywhere in the world. The result, pilots can always communicate with someone on the ground. Avionics Supporting HFDL To use the service, an aircraft only needs a Communications Management Unit CMU , or equivalent and an HFDL data radio. The CMU is an airborne communications router that interfaces with many aircraft communications systems including SATCOM, VHF, HFDL, FMS and others. Global Coverage Today, HFDL is an air ground data link standard with coverage in virtually every corner of the globe, approximately convert 168000000 sqmi km2 where aircraft are never out of touch both in the air and on the ground. Evolving Technology The HFDL network and avionics are a continuing evolution. Recent innovations in avionics software developed by both Honeywell and Collins have enhanced performance and contribute to the service s outstanding message success rates. There is continued investment in the HFDL infrastructure and there is a long term strategy in place to ensure its success. ARINC have been quoted as saying that the system and its use have grown at rates above 20 for each of the past ten years and it now supports over sixty airlines with well over 1,200 aircraft sending more than 1 million messages a month. In 2009 ... Frequency Selection HFDL does not require pilots to dial in specific frequencies, as with HF voice, the data radios constantly scan and select the most efficient frequency to use making operation ... more details
MWband freq 30 to 300 gigahertz GHz bands Extremely highfrequency is the highest radio frequency band radio band . EHF runs the range of Radio frequency frequencies from 30 to 300 gigahertz , above ... 10 mW cm sup 2 sup or less electromagnetic radiation of extremely highfrequency especially ... HighFrequency EHF Therapy. More than 10 000 devices are used for Millimeter Wave Therapy ... wave technology EMSpectrum DEFAULTSORT Extremely HighFrequency Category Radio spectrum de ... haute fr quence hi EHF it Extremely highfrequency lb Millimeterwell nl Extremely highfrequency ne EHF ja no Ekstremt h y frekvens pl Fale milimetrowe pt Extremely highfrequency fi Extremely highfrequency sv Millimeterv gor tr A r y ksek frekans zh ... communications range, it also allows for smaller frequency reuse distances than lower frequencies ... frequency reuse potential. Applications Scientific research This band radio band is commonly used in radio astronomy and remote sensing . Ground based radio astronomy is limited to high altitude sites ... and pressure. The ITU non exclusive passive frequency allocation at 57 59.3 is used for atmospheric ... of Defense satellite F 16 make use of this frequency range. ref name Comments of IEEE Geoscience ... GHz is used for licensed high speed microwave data links, and the 60 GHz band can be used ... to point high bandwidth communication links. These frequencies, as opposed to the 60 GHz frequency, require a transmitting license in the US from the Federal Communications Commission FCC ..., including high speed, point to point wireless local area networks and broadband Internet access . WirelessHD ... high resolution. Uses of the millimeter wave bands include point to point communications, intersatellite ..., to achieve the same high directivity and high gain. The immediate consequence of this high directivity, coupled with the high free space loss at these frequencies, is the possibility of a more efficient ... more details
no footnotes date April 2012 HighFrequency Impact Treatment or HiFIT Method is the treatment of welded steel constructions at the weld transition to increase the fatigue strength. Features The durability and life of dynamically loaded, welded steel structures is determined in many cases by the welds, particular the weld transitions. Through selective treatment of the transitions grinding abrasive cutting abrasive blasting , hammering, etc. , the durability of many designs increase significantly. Hammer ng methods have proven to be particularly effective treatment methods and were within the joint project REFRESH ref http stahl.vaka.kit.edu 276.php Website of the Karlsruhe Institute of Technology KIT Project REFRESH ref extensively studied and developed. The HiFIT process HighFrequency Impact Treatment is such a hammering method that is universally applicable, requires only a low tech equipment and still offers high reproducibility and the possibility for quality control. Operation The HiFIT hammer operates with a hardened pin with a ball resting on the workpiece diameter D 3. This pin is hammered with an adjustable intensity at around 180 300Hz at the weld toe. Local mechanical deformations occur in the form of a treatment track. The weld toe is deformed plastically and bonded. The induced compressive residual stresses in the treatment prevent the track cracking and the crack propagation on the surface. Evidence In numerous experiments at various institutes and universities an 80 to 100 percent increase of fatigue strength and a 5 to 15 fold increase in weld life could be demontrated. The most extensive research project was from 2006 2009 REFRESH life extension of existing and new welded steel structures P702 . In this research project, the HiFIT device was developed and made ... details and FEM supported design methods show the high efficiency with conventional S355J2 and fine ... times of the loads on the weld are transferable. Thus, the use of high tensile steels for lighter ... more details
Unreferenced date September 2007 Certainty An approximation is a representation of something that is not exact, but still close enough to be useful. Although approximation is most often applied to number s, it is also frequently applied to such things as Function mathematics mathematical functions , shape ..., an approximation may yield a sufficiently accurate solution while reducing the complexity of the problem ... rate of evolutionary algorithms, fitness approximation that leads to build model of the fitness function to choose smart search steps is a good solution. The type of approximation used depends ..., and the savings usually in time and effort that can be achieved by approximation. Science ... measurement s, which are constantly compared to one another. The approximation also refers ... wikitable align right Symbols representing approximation style font size xx large & 8784 general approximation style font size xx large asymptotic analysis Approximation usually occurs when an exact ... number of Significant figures significant digits . Approximation theory is a branch of mathematics, a quantitative part of functional analysis . Diophantine approximation deals with approximations of real number s by rational number s. Related to approximation of functions is the Asymptotic analysis .... See also col begin col break Approximately equals sign Approximation error Congruence relation Estimation Fermi estimate Fitness approximation Least squares col break Linear approximation Newton s method Numerical analysis Orders of approximation Runge Kutta methods Successive approximation ADC Taylor series col break Wiktionarypar approximation col end Category Approximations Category Numerical analysis bg br Tostadur cs Aproximace da Approksimation de Approximation es Aproximaci n eo Proksimuma kalkulado fr Approximation ko hi is N mundun it Approssimazione he ... pt Aproxima o ru simple Approximation fi Approksimaatio sv Approximation uk ... more details
Orphan date December 2011 Image HFOV 3100A.jpg thumb right The SensorMedics HighFrequency Oscillatory Ventilator is a patented highfrequency ventilation highfrequency 150 Respiratory rate R sub f sub mechanical ventilator by Cardinal Health . ref name pmid19499589 cite journal author Messier SE, Digeronimo RJ, Gillette RK title Comparison of the Sensormedics 3100A and Bronchotron transporter in a neonatal piglet ARDS model. journal Pediatr Pulmonol year 2009 volume 44 issue 7 pages 693 700 pmid 19499589 doi 10.1002 ppul.21041 pmc url ref The 3100A model was approved for use in the United States by the Food and Drug Administration in 1991 for neonatal application for the treatment of all forms of respiratory failure then subsequently approved in 1995 for Pediatric Application, with no upper weight limit , for treating selected patients failing conventional ventilation. The Highfrequency oscillatory ventilator 3100A The 3100A model is used for infants and children under 35 kilograms 35 kg . ref name pmid21037502 cite journal author Custer JW, Ahmed A, Kaczka DW, Mulreany DG, Hager DN, Simon BA et al. title In vitro performance comparison of the Sensormedics 3100A and B highfrequency oscillatory ventilators. journal Pediatr Crit Care Med year 2011 volume 12 issue 4 pages e176 80 pmid 21037502 doi 10.1097 PCC.0b013e3181fe3028 pmc url ref 3100B The 3100B model is used for all other people greater than 35 kilograms 35 kg . ref name pmid21037502 Controls and settings Bias flow Bias flow Adjusting Bias Flow will affect mean P sub aw sub . Lowering bias flow may decrease ..., McGeorge AD, Hancock SW title Failure of adequate ventilation using Sensormedics 3100A HighFrequency ... where lung recruitment is necessary. FrequencyFrequency R sub f sub is the number of breaths in one ... values and ranges The smaller the patient, the higher the frequency. The larger the patient, the lower the frequency. Changes in frequency Decrease in frequency increased tidal volume . Increase in frequency ... more details
Orphan date February 2009 Ultra HighFrequency was a Long Island Long Island, New York based rock band formed in 2001 on Long Island by Frank Fussa vocals, guitar , Jon Brown guitar vocals , Chris Johanidesz bass vocals and Dennis Joseph drums vocals . Dennis left in 2002. It wasn t until 2004 that their first official record Sun Never Sets in Dramaville was released. The band s next full length Matter in Time 2006 was recorded in Seattle, Washington by producer engineer Barrett Jones. Upon release the band toured with fellow Long Island band Brand New. As of 2007 the band relocated to Los Angeles to continue writing and touring. By the end of 2007, the band called it quits. Frank and Chris have emerged with a new band called Morning Fuzz. Discography Albums 2006 Matter in Time 2004 Sun Never Sets in Dramaville Singles EP 2003 Joyride Lies 2002 This is Important EP Compilation tracks Beer The Movie 2006 Back to Bacon from Matter in Time Demos Basement Demo 2001 External links http www.billboard.com bbcom bio index.jsp?pid 165755 Billboard.com http www.ultrahighmusic.com Official Website http www.myspace.com ultrahighfrequency Ultra HighFrequency MySpace http www.ultrahighmusic.com images UHFAPPress.jpg Alternative Press Magazine http www.ultrahighmusic.com images UHF auralfix.pdf Aural Fix Magazine Category American rock music groups Category Musical groups from Long Island Category Musical groups established in 2001 US rock band stub ... more details
Unreferenced date December 2009 The HighFrequency Global Communications System HF GCS is a network of single sideband shortwave transmitters of the United States Air Force which is used to communicate with aircraft in flight, ground stations and some United States Navy surface assets. All worldwide receiving and transmitting sites in the HF GCS system are remotely controlled from Andrews AFB . Before 1 October 2002 it was known as the Global HighFrequency System GHFS . HF GCS stations tend to operate in the aviation bands clustered around 5, 8 and 11 12 MHz, although other frequencies are in use. The primary HF GCS voice frequencies are 4724.0 kHz, 6739.0 kHz, 8992.0 kHz, 11175.0 kHz, 13200.0 kHz and 15016.0 kHz. In addition to the HF GCS, U.S. aircraft frequently use Military Affiliate Radio System MARS HF stations 13927.0 kHz and Canadian Forces HF stations 11232.0 kHz to relay messages. One common use for the HF GCS is to place telephone calls from the aircraft in flight by means of the Defense Switched Network DSN to an Air Force base to obtain local weather conditions, to arrange for refueling, and to inform the base of the number of passengers and crew. The HF GCS also carries Emergency Action Messages . Although transmissions are often single sideband, the use of the Automatic link establishment ALE transmission mode is more and more common. New South Wales HF GCS complements the use of satellite communications between aircraft and ground stations. Stations of the HF GCS Network Andersen Global, Andersen Air Force Base , Guam Island Andrews Global, Andrews Air Force Base , Maryland USA Ascension Global, RAF Ascension Island , Atlantic Ocean Croughton Global, RAF Croughton , United Kingdom Diego Garcia Global, Diego Garcia Naval Station, Indian Ocean Elmendorf Global, Elmendorf Air Force Base , Alaska Hickam Global, Hickam Air Force Base , Hawaii Lajes Global, Lajes Field , Azores McClellan Global aka West Coast Global ... more details
operating at highfrequency HF . Modern direction finding of both communications and noncommunications ... on the highfrequency radio transmitters employed by the German Kriegsmarine in World War II. There were severe technical problems of engineering effective highfrequency direction finding systems ... RAFTER remotely confirming that a superhet radio receiver is listening to a certain frequency References reflist refbegin cite book title Secret Weapon U.S. HighFrequency Direction Finding in the Battle ... information from unintentional signals from transmitters, such as the oscillator frequency of a superheterodyne ... of radar. This allowed hunter killer ships and aircraft to be dispatched at high speed in the direction ... Radio frequency identification Category World War II British electronics Category World War II ... more details
range Frequency deviation Frequency spectrum Hearing range Highfrequency limit Hyperacusis Interaction ... frequency top to highest frequency bottom . f is the frequency in hertz Hz , meaning the number of cycles ... are reciprocal mathematics reciprocals . Frequency is the number of occurrences of a repeating event per unit time . It is also referred to as temporal frequency . The period is the duration of one turn geometry cycle in a repeating event, so the period is the reciprocal mathematics reciprocal of the frequency. For example, if a newborn baby s heart beats at a frequency of 120 times a minute, its ... processes, such as rotation , oscillation s, or wave s, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics , acoustics , and radio , frequency ... SI units, the unit of frequency is the hertz Hz , named after the German physicist Heinrich Hertz ... by one cycle, and is the reciprocal mathematics reciprocal of the frequency f math T frac 1 f math ... than those above. The horizontal axis represents time. By counting Calculating the frequency of a repeating ... within 15 seconds the frequency is math f frac 71 15 , mbox sec approx 4.7 , mbox hertz , math If the number ... an average error in the calculated frequency of f 1 2 T sub m sub , or a fractional ... interval and f is the measured frequency. This error decreases with frequency, so it is a problem ... the frequency of rotating or vibrating objects is to use a stroboscope . This is an intense repetitively flashing light strobe light whose frequency can be adjusted with a calibrated timing circuit. The strobe light is pointed at the rotating object and the frequency adjusted up and down. When the frequency of the strobe equals the frequency of the rotating or vibrating object, the object completes ... when illuminated by the strobe the object appears stationary. Then the frequency can be read from the calibrated ... multiple of the strobing frequency will also appear stationary. By frequency counter Higher ... more details
Infobox musical artist name The Frequency image image size 220 caption From left to right Marc Cazorla, Alex Stiff background group or band origin Los Angeles , California , United States genre Indie rock , Electronica , Ambient music Ambient years active 2005 present label Ropeadope Records br Trussed website http www.thefrequencymusic.net Official Website current members Marc Cazorla br Alex Stiff br Mark Quinn The Frequency are an independent rock band from Los Angeles, CA. Marc Cazorla and Alex Stiff are the core songwriting and recording duo behind the music and use an array of analog and vintage instruments in creating sounds that have been described by NME as stripped back music strengthened by simplicity as much as beauty . Q Magazine has given the new release Morning to 3 A.M. 3 out of 4 stars and hails the band as able to form perfectly crafted Air like synth pop while also stretching their wings on the 17 minute ever shifting psych rock track Ego Is the Drug 3 A.M. The Frequency have recently signed a worldwide publishing deal with http www.chrysalismusic.co.uk Chrysalis Music in the UK and the song Jim Gordon Part II has been heard all over the globe due to being licensed for a yearlong BlackBerry television commercial campaign. Music from The Frequency can also be found ... Daily newspaper to declare The Frequency should be on every rock fan s radar. The Frequency s Jim Gordon ... Machine self release 2007 The Frequency EP Ropeadope Digital Compilations Explorations Classic Picante ... Free Download Oct 09 http www.nme.com reviews the frequency 10684 NME Review July 09 http www.dmcupdate.com ... External links http www.thefrequencymusic.net The Frequency s official website http www.myspace.com thefrequencymusic The Frequency s myspace http www.facebook.com pages The Frequency 5877798251?ref mf The Frequency on Facebook http www.twitter.com the frequency The Frequency on Twitter http absenceofgiants.com www.absenceofgiants.com DEFAULTSORT Frequency, The Category American indie rock groups ... more details
Rational approximation may refer to Diophantine approximation , the approximation of real numbers by rational numbers. Pad approximation , the approximation of functions by rational functions. See also Simple rational approximation Mathdab ... more details
and so Planck s law approximately equals the Wien approximation at high frequencies. Other approximations ... of energy per unit surface area per unit time per unit solid angle per unit frequency emitted at a frequency ... sub and frequency sub max sub of ref name irwin2007 citation first1 Judith A. last1 Irwin title Astrophysics ... max 5.88 times 10 10 cdot T math in cgs units. Relation to Planck s law The Wien approximation was originally ... to accurately describe long wavelength low frequency emission. However, it was soon superseded by Planck s law , developed by Max Planck . Unlike the Wien approximation, Planck s law accurately describes ... nu 3 c 2 frac 1 e frac h nu kT 1 math ref name rybickilightman1979 The Wien approximation ... more details
unreferenced date March 2008 In science , engineering , and other quantitative disciplines, orders of approximation refer to formal or informal terms for how precise an approximation is, and to indicate progressively more refined approximations in increasing order of precision, a zeroth order approximation, a first order approximation, a second order approximation, and so forth. Formally, an n th order approximation is one where the order of magnitude of the error is at most math x n math , or in terms of big O notation , the error is math O x n . math In suitable circumstances, approximating a function by a Taylor polynomial of degree n yields an n th order approximation, by Taylor s theorem a first order approximation is a linear approximation , and so forth. The term is also used more loosely, as detailed below. Usage in science and engineering Zeroth order approximation also 0th order ... 3,914 people in actuality. This is also sometimes referred to as an order of magnitude approximation. A zeroth order approximation of a function mathematics function that is, mathematics mathematically ... math y 3,3,5 , math math y sim f x 3.67 , math is an approximate fit to the data. First order approximation ... is often given the town has 4 10 sup 3 sup or four thousand residents . A first order approximation ... approximation , straight line with a slope a polynomial of degree 1. For example, math x 0,1,2 ... by simply averaging the y values. Other methods for selecting a constant approximation can be used. Second order approximation also 2nd order is the term scientists use for a decent quality answer ... approximation of a function that is, mathematically determining a formula to fit multiple data ... referred to by number. A third order approximation would be required to fit four data ... of the earth affects our experiment, but it s such a high order effect that we wouldn t be able ... at the annual calibration. In this usage, the ordinality of the approximation is not exact, but is used ... more details
The eikonal approximation is a method of approximation useful in wave scattering equations within the realms of quantum mechanics , optics , quantum electrodynamics , and partial wave expansion Informal description The main advantage the eikonal approximation offers is that the equations reduce to a differential equation in a single variable. This reduction into a single variable is the result of the straight line approximation or the eikonal approximation which allows us to choose the straight line as a special direction. Relation to the WKB approximation The early steps involved in the eikonal approximation in quantum mechanics are very closely related to the WKB approximation . It, like the eikonal approximation, reduces the equations into a differential equation in a single variable. But the difficulty with the WKB approximation is that this variable is described by the trajectory of the particle which, in general, is complicated. Formal description Empty section date July 2010 See also Eikonal equation References http www.nhn.ou.edu shajesh eikonal sp.pdf Eikonal Approximation K. V. Shajesh Department of Physics and Astronomy, University of Oklahoma Category Mathematical analysis Math stub Quantum stub ... more details
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