ERIC Educational Resources Information Center
Scott, Paul
2009-01-01
These days, multiplying two numbers together is a breeze. One just enters the two numbers into one's calculator, press a button, and there is the answer! It never used to be this easy. Generations of students struggled with tables of logarithms, and thought it was a miracle when the slide rule first appeared. In this article, the author discusses…
Adding and Subtracting Vectors: The Problem with the Arrow Representation
ERIC Educational Resources Information Center
Heckler, Andrew F.; Scaife, Thomas M.
2015-01-01
A small number of studies have investigated student understanding of vector addition and subtraction in generic or introductory physics contexts, but in almost all cases the questions posed were in the vector arrow representation. In a series of experiments involving over 1000 students and several semesters, we investigated student understanding…
Adding and subtracting vectors: The problem with the arrow representation
NASA Astrophysics Data System (ADS)
Heckler, Andrew F.; Scaife, Thomas M.
2015-06-01
A small number of studies have investigated student understanding of vector addition and subtraction in generic or introductory physics contexts, but in almost all cases the questions posed were in the vector arrow representation. In a series of experiments involving over 1000 students and several semesters, we investigated student understanding of vector addition and subtraction in both the arrow and algebraic notation (using i ^, j ^, k ^) in generic mathematical and physics contexts. First, we replicated a number of previous findings of student difficulties in the arrow format and discovered several additional difficulties, including the finding that different relative arrow orientations can prompt different solution paths and different kinds of mistakes, which suggests that students need to practice with a variety of relative orientations. Most importantly, we found that average performance in the i j k format was typically excellent and often much better than performance in the arrow format in either the generic or physics contexts. Further, while we find that the arrow format tends to prompt students to a more physically intuitive solution path, we also find that, when prompted, student solutions in the i j k format also display significant physical insights into the problem. We also find a hierarchy in correct answering between the two formats, with correct answering in the i j k format being more fundamental than for the arrow format. Overall, the results suggest that many student difficulties with these simple vector problems lie with the arrow representation itself. For instruction, these results imply that introducing the i j k notation (or some equivalent) with the arrow notation concurrently may be a very useful way to improve student performance as well as help students to learn physics concepts involving vector addition and subtraction.
Medicaid Contradictions: Adding, Subtracting, and Redeterminations in Illinois.
Koetting, Michael
2016-04-01
States are required to conduct annual Medicaid redeterminations. How these redeterminations are undertaken is crucial to determining the nature of Medicaid coverage. There can be wide variations in the proportion of clients disenrolled, with potentially large numbers of people disenrolled each year. This case study of Illinois Medicaid shows how, as the Affordable Care Act added people, redeterminations were taking people off the rolls-about 25 percent of all Medicaid clients were disenrolled in one year. Many of these people were no longer eligible, but it appears that a larger number were in fact eligible but simply failed to comply with administrative requirements in a timely way. Balancing between the two imperatives of program integrity and continuity of care is a difficult act for Medicaid programs. The Illinois experience also illustrates impacts on information technology and outsourcing of eligibility functions, not to mention budget considerations. PMID:26732317
Quality Index for Stereoscopic Images by Separately Evaluating Adding and Subtracting
Yang, Jiachen; Lin, Yancong; Gao, Zhiqun; Lv, Zhihan; Wei, Wei; Song, Houbing
2015-01-01
The human visual system (HVS) plays an important role in stereo image quality perception. Therefore, it has aroused many people’s interest in how to take advantage of the knowledge of the visual perception in image quality assessment models. This paper proposes a full-reference metric for quality assessment of stereoscopic images based on the binocular difference channel and binocular summation channel. For a stereo pair, the binocular summation map and binocular difference map are computed first by adding and subtracting the left image and right image. Then the binocular summation is decoupled into two parts, namely additive impairments and detail losses. The quality of binocular summation is obtained as the adaptive combination of the quality of detail losses and additive impairments. The quality of binocular summation is computed by using the Contrast Sensitivity Function (CSF) and weighted multi-scale (MS-SSIM). Finally, the quality of binocular summation and binocular difference is integrated into an overall quality index. The experimental results indicate that compared with existing metrics, the proposed metric is highly consistent with the subjective quality assessment and is a robust measure. The result have also indirectly proved hypothesis of the existence of binocular summation and binocular difference channels. PMID:26717412
Generation of photon-added coherent states via photon-subtracted generalised coherent states
NASA Astrophysics Data System (ADS)
Mojaveri, Bashir; Dehghani, Alireza
2014-10-01
Based on previous work [A. Dehghani, B. Mojaveri, J. Phys. A 45, 095304 (2012)], we introduce photon-subtracted generalised coherent states (PSGCSs) |z,m⟩r: = am|z⟩r, where m is a nonnegative integer and |z⟩r denote the generalised coherent states (GCSs). We have shown that the states |z,m⟩r are eigenstates of a non-Hermitian operator f(n̂,m)â, where f(n̂,m) is a nonlinear function of the number operator N̂ . Also, the states | z, - m ⟩ r can be considered as another set of eigenstates for negative values of m. They span the truncated Fock space without the first m lowest-lying basis states: | 0 ⟩ , | 1 ⟩ , | 2 ⟩ ,...,| m - 1 ⟩ which are reminiscent of the so-called photon-added coherent states. The resolution of the identity property, which is the most important property of coherent states, is realised for |z,m⟩r as well as for |z, - m⟩r. Some nonclassical features such as sub-Poissonian statistics and quadrature squeezing of the states |z, ± m⟩r are compared. We show that the annihilation operator diminishes the mean number of photons of the initial state |z⟩r. Finally we show that |z,m⟩r can be produced through a simple theoretical scheme.
Quality Index for Stereoscopic Images by Separately Evaluating Adding and Subtracting.
Yang, Jiachen; Lin, Yancong; Gao, Zhiqun; Lv, Zhihan; Wei, Wei; Song, Houbing
2015-01-01
The human visual system (HVS) plays an important role in stereo image quality perception. Therefore, it has aroused many people's interest in how to take advantage of the knowledge of the visual perception in image quality assessment models. This paper proposes a full-reference metric for quality assessment of stereoscopic images based on the binocular difference channel and binocular summation channel. For a stereo pair, the binocular summation map and binocular difference map are computed first by adding and subtracting the left image and right image. Then the binocular summation is decoupled into two parts, namely additive impairments and detail losses. The quality of binocular summation is obtained as the adaptive combination of the quality of detail losses and additive impairments. The quality of binocular summation is computed by using the Contrast Sensitivity Function (CSF) and weighted multi-scale (MS-SSIM). Finally, the quality of binocular summation and binocular difference is integrated into an overall quality index. The experimental results indicate that compared with existing metrics, the proposed metric is highly consistent with the subjective quality assessment and is a robust measure. The result have also indirectly proved hypothesis of the existence of binocular summation and binocular difference channels. PMID:26717412
Blankenship, Jennifer M; Granados, Kirsten; Braun, Barry
2014-11-01
Recent evidence suggests that, like adding exercise, reducing sitting time may improve cardiometabolic health. There has not been a direct comparison of the 2 strategies with energy expenditure held constant. The purpose of this study was to compare fasting and postmeal glucose and insulin concentrations in response to a day with frequent breaks from sitting but no exercise versus considerable sitting plus moderate exercise. Ten sedentary overweight/obese office workers were tested in 3 conditions: (i) walking per activity guidelines (AGW): sitting for majority of workday with a 30 min pre-lunch walk; (ii) frequent long breaks (FLB): no structured exercise but frequent breaks from sitting during workday with energy expenditure matched to AGW; and (iii) frequent short breaks (FSB): number of breaks matched to FLB, but duration of breaks were shorter. Plasma glucose and insulin areas under the curve were measured in response to a meal tolerance test (MTT) at the end of the workday and interstitial glucose was evaluated throughout the day and overnight using continuous glucose monitoring. Using repeated-measures linear mixed models, area under the curve of plasma glucose or insulin after the MTT was not different between conditions. Glycemic variability was lower in FLB compared with AGW (p < 0.05), and nocturnal duration of elevated glucose (>7.8 mmol/L) was shorter after FLB (2.5 ± 2.5 min) than AGW (32.7 ± 16.4 min) or FSB (45.6 ± 29.6 min, p = 0.05). When energy expenditure was matched, breaks from sitting approximated the effects of moderate-intensity exercise on postmeal glucose and insulin responses and more effectively constrained glycemic variability. PMID:25166626
ERIC Educational Resources Information Center
Henderson, Jimmy Dale
2011-01-01
This study examined the perceptions of principals, teachers, and support staff at 3 PREPS-identified value added and three PREPS-identified value subtracted elementary schools in Mississippi to determine if there were "effective schools" practices in the areas of instructional and organizational systems that were unique to either group. The…
Pierce, Paul E.
1986-01-01
A hardware processor is disclosed which in the described embodiment is a memory mapped multiplier processor that can operate in parallel with a 16 bit microcomputer. The multiplier processor decodes the address bus to receive specific instructions so that in one access it can write and automatically perform single or double precision multiplication involving a number written to it with or without addition or subtraction with a previously stored number. It can also, on a single read command automatically round and scale a previously stored number. The multiplier processor includes two concatenated 16 bit multiplier registers, two 16 bit concatenated 16 bit multipliers, and four 16 bit product registers connected to an internal 16 bit data bus. A high level address decoder determines when the multiplier processor is being addressed and first and second low level address decoders generate control signals. In addition, certain low order address lines are used to carry uncoded control signals. First and second control circuits coupled to the decoders generate further control signals and generate a plurality of clocking pulse trains in response to the decoded and address control signals.
Pierce, P.E.
A hardware processor is disclosed which in the described embodiment is a memory mapped multiplier processor that can operate in parallel with a 16 bit microcomputer. The multiplier processor decodes the address bus to receive specific instructions so that in one access it can write and automatically perform single or double precision multiplication involving a number written to it with or without addition or subtraction with a previously stored number. It can also, on a single read command automatically round and scale a previously stored number. The multiplier processor includes two concatenated 16 bit multiplier registers, two 16 bit concatenated 16 bit multipliers, and four 16 bit product registers connected to an internal 16 bit data bus. A high level address decoder determines when the multiplier processor is being addressed and first and second low level address decoders generate control signals. In addition, certain low order address lines are used to carry uncoded control signals. First and second control circuits coupled to the decoders generate further control signals and generate a plurality of clocking pulse trains in response to the decoded and address control signals.
Numerical integration of subtraction terms
NASA Astrophysics Data System (ADS)
Seth, Satyajit; Weinzierl, Stefan
2016-06-01
Numerical approaches to higher-order calculations often employ subtraction terms, both for the real emission and the virtual corrections. These subtraction terms have to be added back. In this paper we show that at NLO the real subtraction terms, the virtual subtraction terms, the integral representations of the field renormalization constants and—in the case of initial-state partons—the integral representation for the collinear counterterm can be grouped together to give finite integrals, which can be evaluated numerically. This is useful for an extension towards next-to-next-to-leading order.
Chase, R.L.
1963-05-01
An electronic fast multiplier circuit utilizing a transistor controlled voltage divider network is presented. The multiplier includes a stepped potentiometer in which solid state or transistor switches are substituted for mechanical wipers in order to obtain electronic switching that is extremely fast as compared to the usual servo-driven mechanical wipers. While this multiplier circuit operates as an approximation and in steps to obtain a voltage that is the product of two input voltages, any desired degree of accuracy can be obtained with the proper number of increments and adjustment of parameters. (AEC)
Thomas, R.E.
1959-01-20
An electronic circuit is presented for automatically computing the product of two selected variables by multiplying the voltage pulses proportional to the variables. The multiplier circuit has a plurality of parallel resistors of predetermined values connected through separate gate circults between a first input and the output terminal. One voltage pulse is applied to thc flrst input while the second voltage pulse is applied to control circuitry for the respective gate circuits. Thc magnitude of the second voltage pulse selects the resistors upon which the first voltage pulse is imprcssed, whereby the resultant output voltage is proportional to the product of the input voltage pulses
Collier, D.M.; Meeks, L.A.; Palmer, J.P.
1961-01-31
S>An electronic multiplier is described for use in analog computers. Two electrical input signals are received; one controls the slope of a saw-tooth voltage wave while the other controls the time duration of the wave. A condenser and diode clamps are provided to sustain the crest voltage reached by the wave, and for storing that voltage to provide an output signal which is a steady d-c voltage.
Digital subtraction laryngography
Brown, B.W.; Enzmann, D.R.; Hopp, M.L.; Castellino, R.A.
1983-06-01
Digital subtraction laryngography was used to evaluate laryngeal function in 8 patients: 4 with normal larynxes and 4 with laryngeal disease. Subtracted digital images provided a dynamic display of the extent and symmetry of vocal cord excursions and pyriform sinus inflation, and the vocal cord resting position was also clearly depicted. The technical details of digital subtraction laryngography and its application are described.
Thomas, R.E.
1959-08-25
An electronic multiplier circuit is described in which an output voltage having an amplitude proportional to the product or quotient of the input signals is accomplished in a novel manner which facilitates simplicity of circuit construction and a high degree of accuracy in accomplishing the multiplying and dividing function. The circuit broadly comprises a multiplier tube in which the plate current is proportional to the voltage applied to a first control grid multiplied by the difference between voltage applied to a second control grid and the voltage applied to the first control grid. Means are provided to apply a first signal to be multiplied to the first control grid together with means for applying the sum of the first signal to be multiplied and a second signal to be multiplied to the second control grid whereby the plate current of the multiplier tube is proportional to the product of the first and second signals to be multiplied.
NASA Technical Reports Server (NTRS)
Liu, Hua-Kuang; Chao, Tien-Hsin
1988-01-01
Report reviews optical image subtraction techniques developed during years 1975 through 1985. Useful in such disciplines as studies of earth resources, meteorology, automatic surveillance, pattern recognition, studies of urban growth, and compression of bandwidth in communication systems. Describes following real-time techniques: source encoding, polarization modulation, pseudocolor image-difference detection, holographic-shear-lens technique, and nonlinear electro-optics. Reported non-real-time image-subtraction techniques are following, all of which involve intensity subtraction: speckle-diffuser encoding, speckle-pattern encoding, halftone-screen encoding,and polarization-shifted carrier encoding. Offers an attractive alternative to digital electronic image subtraction, is faster and treats all parts of images simultaneously.
Pressure multiplying dispenser
DeFord, Henry S.; Moss, Owen R.
1986-01-01
A pressure multiplying dispenser for delivering fluid, preferably as a spray to the atmosphere, from a source of fluid, preferably a spray bottle, is described. The dispenser includes in combination a hollow cylindrical member, a nozzle delivery tube within the cylindrical member and a hollow actuator piston slideable within the cylindrical member which acts to multiply the pressure of a squeeze applied to the spray bottle.
Comby, G.
1996-10-01
The Ceramic Electron Multipliers (CEM) is a compact, robust, linear and fast multi-channel electron multiplier. The Multi Layer Ceramic Technique (MLCT) allows to build metallic dynodes inside a compact ceramic block. The activation of the metallic dynodes enhances their secondary electron emission (SEE). The CEM can be used in multi-channel photomultipliers, multi-channel light intensifiers, ion detection, spectroscopy, analysis of time of flight events, particle detection or Cherenkov imaging detectors. (auth)
NASA Astrophysics Data System (ADS)
Gal-Yam, Avishay; Zackay, Barak; Ofek, Eran O.
2016-01-01
Transient detection and flux measurement via image subtraction are fundamental to time domain astronomy. Starting from first principles, we develop the optimal linear statistic for transient detection and flux measurement and any other image-difference hypothesis testing. We derive a simple closed-form statistic that: (1) Is mathematically proven to be the optimal subtraction statistic in the limit of background-dominated noise within the family of linear solutions, that contains all previously suggested methods; (2) Does not leave subtraction or deconvolution artifacts, even in the vicinity of bright stars; (3) Is an order of magnitude faster to compute than popular methods; (4) Allowsautomatic transient detection down to the theoretical sensitivity limit by providing a reliable, well-defined detection significance; (5) Is symmetric to the interchange of the new and reference images; (6) Is numerically stable; and (7) Is trivial to implement. We demonstratethat the correct way to prepare a reference image is the proper image co-addition presented in Zackay & Ofek 2015. Finally, we show a proper image subtraction statistic, that, along with its point spread functions, is a sufficient statistic for any decision or measurement on the difference image. This allows accurate filtration of image artifacts such as cosmic rays and hot pixels. We demonstrate this method on simulated data as well as on observations from the Palomar Transient Factory.
NASA Astrophysics Data System (ADS)
Frixione, Stefano; Grazzini, Massimiliano
2005-06-01
We propose a framework for the implementation of a subtraction formalism at NNLO in QCD, based on an observable- and process-independent cancellation of infrared singularities. As a first simple application, we present the calculation of the contribution to the e+e- dijet cross section proportional to CFTR.
The Multiply Handicapped Child.
ERIC Educational Resources Information Center
Wolf, James M., Ed.; Anderson, Robert M., Ed.
Articles presented in the area of the medical and educational challenge of the multiply handicapped child are an overview of the problem, the increasing challenge, congenital malformations, children whose mothers had rubella, prematurity and deafness, the epidemiology of reproductive casualty, and new education for old problems. Discussions of…
NASA Technical Reports Server (NTRS)
Baumert, L. D.; Mceliece, R. J.; Solomon, G.
1976-01-01
A general technique, called decoding with multipliers, is presented that can be used to decode any linear code. The technique is applied to the (48,24) quadratic residue code and yields the first known practical decoding algorithm for this powerful code.
Pediatric digital subtraction angiography
Amundson, G.M.; Wesenberg, R.L.; Mueller, D.L.; Reid, R.H.
1984-12-01
Experience with intravenous digital subtraction angiography (DSA) in infants and children is limited, although its relative rate of performance, low complication rate, and diagnostic accuracy indicate great potential. The authors performed 87 DSA examinations (74 patients) and obtained sufficient detail to facilitate diagnosis in most cases. The major problems of patient movement and overlapping vessels can be minimized by judicious use of sedation and strict attention to technique. Exposure of patients to radiation has not been a limiting factor since our system uses low exposure factors. Our results demonstrate that DSA has wide applicability to many organ systems and is especially useful in intracranial disease and for preoperative evaluation of neoplasms.
NASA Astrophysics Data System (ADS)
Shmayda, W. T.
1981-11-01
The Plasma Current Multiplier (PCM) is a well-stabilized low pressure arc discharge with the capability of multiplying the initial electron current injected into the device. Experimentally the PCM gain per unit length (g) was found to decrease with increasing arc current at very low arc current densities, to remain constant at moderate arc current densities, and to decrease asymptotically towards unity at extremely high current densities. Theoretically, sheath thickening and neutral rarefaction due to local gas heating have been identified as the phenomena responsible for the PCM gain behavior at the very low and high arc current densities respectively. Experimental confirmation of the gain dependence on mass and tube radius originally predicted by the Stangeby and Allen theory was extended to several atomic species. An emissionless source of electrons was constructed and tested, thus expanding the operating capacity of this device to reactive gases.
Hardware Implementation of a Bilateral Subtraction Filter
NASA Technical Reports Server (NTRS)
Huertas, Andres; Watson, Robert; Villalpando, Carlos; Goldberg, Steven
2009-01-01
its position in the window as well as the pixel value for the central pixel of the window. The absolute difference between these two pixel values is calculated and used as an address in a lookup table. Each processing element has a lookup table, unique for its position in the window, containing the weight coefficients for the Gaussian function for that position. The pixel value is multiplied by the weight, and the outputs of the processing element are the weight and pixel-value weight product. The products and weights are fed to the adder tree. The sum of the products and the sum of the weights are fed to the divider, which computes the sum of products the sum of weights. The output of the divider is denoted the bilateral smoothed image. The smoothing function is a simple weighted average computed over a 3 3 subwindow centered in the 9 9 window. After smoothing, the image is delayed by an additional amount of time needed to match the processing time for computing the bilateral smoothed image. The bilateral smoothed image is then subtracted from the 3 3 smoothed image to produce the final output. The prototype filter as implemented in a commercially available FPGA processes one pixel per clock cycle. Operation at a clock speed of 66 MHz has been demonstrated, and results of a static timing analysis have been interpreted as suggesting that the clock speed could be increased to as much as 100 MHz.
ERIC Educational Resources Information Center
Nelson, Jane Bray
2012-01-01
As a new physics teacher, I was explaining how to find the weight of an object sitting on a table near the surface of the Earth. It bothered me when a student asked, "The object is not accelerating so why do you multiply the mass of the object by the acceleration due to gravity?" I answered something like, "That's true, but if the table were not…
Terahertz Schottky Multiplier Sources
NASA Technical Reports Server (NTRS)
Schlecht, Erich T.
2007-01-01
This viewgraph presentation reviews the multiplier source technologies and the status/Performance of THz multiplier sources. An example of a THz application is imaging radar. The presentation reviews areas of requirements for THz sources: (1) Figures of merit, (i.e., Frequency Terahertz for high resolution Bandwidth of at least 15 GHz for high range resolution Efficiency (i.e., minimize power supply requirements) (2) Output power: (i.e., Milliwatts below 800 GHz, 10s of microwatts above 1 THz, 1-2 microwatts near 2 THz (3) Mechanical--stability, compact, low mass (4) Environmental -- radiation, vibration, thermal. Several sources for 0.3 - 2 THz are reviewed: FIR lasers, quantum cascade lasers (QCL), backward-wave oscillator (BWO), and Multiplier sources. The current state of the art (SoA) is shown as Substrateless Technology. It also shows where the SoA is for devices beyond 1 THz. The presentation concludes by reviewing the options for future development, and 2 technology roadmaps
NASA Astrophysics Data System (ADS)
Nelson, Jane Bray
2012-03-01
As a new physics teacher, I was explaining how to find the weight of an object sitting on a table near the surface of the Earth. It bothered me when a student asked, "The object is not accelerating so why do you multiply the mass of the object by the acceleration due to gravity?" I answered something like, "That's true, but if the table were not there, the object would accelerate at that rate." The really determined students might go on to ask, "Yes, but what if the object were already sitting on the surface of the Earth?" About that time, I would hope the bell would ring so that this whole discussion could be delayed until the next day. The next day, I would explain that the newton unit is the same as a kg-m/s2, so multiplying the mass in kilograms times the acceleration due to gravity would give an answer in newtons. It all made sense to me, but I am sure that the students just went along with me to get the right answer.
Monolithic THz Frequency Multipliers
NASA Technical Reports Server (NTRS)
Erickson, N. R.; Narayanan, G.; Grosslein, R. M.; Martin, S.; Mehdi, I.; Smith, P.; Coulomb, M.; DeMartinez, G.
2001-01-01
Frequency multipliers are required as local oscillator sources for frequencies up to 2.7 THz for FIRST and airborne applications. Multipliers at these frequencies have not previously been demonstrated, and the object of this work was to show whether such circuits are really practical. A practical circuit is one which not only performs as well as is required, but also can be replicated in a time that is feasible. As the frequency of circuits is increased, the difficulties in fabrication and assembly increase rapidly. Building all of the circuit on GaAs as a monolithic circuit is highly desirable to minimize the complexity of assembly, but at the highest frequencies, even a complete monolithic circuit is extremely small, and presents serious handling difficulty. This is compounded by the requirement for a very thin substrate. Assembly can become very difficult because of handling problems and critical placement. It is very desirable to make the chip big enough to that it can be seen without magnification, and strong enough that it may be picked up with tweezers. Machined blocks to house the chips present an additional challenge. Blocks with complex features are very expensive, and these also imply very critical assembly of the parts. It would be much better if the features in the block were as simple as possible and non-critical to the function of the chip. In particular, grounding and other electrical interfaces should be done in a manner that is highly reproducible.
Enhancing quantum entanglement by photon addition and subtraction
NASA Astrophysics Data System (ADS)
Navarrete-Benlloch, Carlos; García-Patrón, Raúl; Shapiro, Jeffrey H.; Cerf, Nicolas J.
2012-07-01
The non-Gaussian operations effected by adding or subtracting a photon on entangled optical beams emerging from a parametric down-conversion process have been suggested to enhance entanglement. Heralded photon addition or subtraction is, as a matter of fact, at the heart of continuous-variable entanglement distillation. The use of such processes has recently been experimentally demonstrated in the context of the generation of optical coherent-state superpositions or the verification of canonical commutation relations. Here, we carry out a systematic study of the effect of local photon additions and subtractions on a two-mode squeezed vacuum state, showing that the entanglement generally increases with the number of such operations. This is analytically proven when additions or subtractions are restricted to one mode only, while we observe that the highest entanglement is achieved when these operations are equally shared between the two modes. We also note that adding photons typically provides a stronger entanglement enhancement than subtracting photons, while photon subtraction performs better in terms of energy efficiency. Furthermore, we analyze the interplay between entanglement and non-Gaussianity, showing that it is more subtle than previously expected.
NASA Astrophysics Data System (ADS)
Gabbiani, F.; Krapp, H.; Koch, C.; Laurent, G.
1998-03-01
LGMD and DCMD are a pair of identified neurons in the locust brain thought to be involved in visually triggered escape behavior. LGMD integrates visual inputs in its dendritic arbor, converts them into spikes transmitted in a 1:1 manner to DCMD which relays this information to motor centers. We measured the spike activity of DCMD during simulated object approach and observed that its peak occured prior to the expected collision. The time difference between peak activity and collision depended linearly on the ratio of object size to approach velocity, as expected if LGMD/DCMD were detecting the moment in time when the approaching object reaches a fixed angular threshold θ_thresh on the locust's retina. The response of LGMD/DCMD could be fitted by multiplying the angular velocity at which an approaching object is increasing in size over the retina, dot θ, with an exponential function of the object's angular size, θ: f(t) = g(dot θ(t-δ) e^-α θ(t-δ)) where g is a static non-linearity, α a constant related to the angular threshold detected by LGMD/DCMD (θ_thresh = arctan (2/α)) and δ denotes the lag of the neuronal response with respect to the stimulus. This suggests that LGMD/DCMD derives its angular threshold sensitivity by multiplying dot θ with an exponential of θ. A biophysical implementation would be through linear summation of excitatory and inhibitory inputs proportional to log(dot θ) and -α θ, followed by a conversion to spike rate according to the static non-linearity (g circ exp). We have performed several experiments to test this hypothesis.
Subtraction Facts with Pattern Explorations.
ERIC Educational Resources Information Center
Beard, Earl M. L.; Polis, A. Richard
1981-01-01
The subtraction ideas presented are designed for elementary and junior high school children, yet are felt to be flexible enough to offer some challenge for high school students, particularly in algebra. (MP)
Multiplier Architecture for Coding Circuits
NASA Technical Reports Server (NTRS)
Wang, C. C.; Truong, T. K.; Shao, H. M.; Deutsch, L. J.
1986-01-01
Multipliers based on new algorithm for Galois-field (GF) arithmetic regular and expandable. Pipeline structures used for computing both multiplications and inverses. Designs suitable for implementation in very-large-scale integrated (VLSI) circuits. This general type of inverter and multiplier architecture especially useful in performing finite-field arithmetic of Reed-Solomon error-correcting codes and of some cryptographic algorithms.
UWB delay and multiply receiver
Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.
2013-09-10
An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.
NASA Technical Reports Server (NTRS)
Strekalov, Dmitry V.; Yu, Nan
2010-01-01
Optical sidebands have been generated with relative frequency tens to hundreds of GHz by using optical sidebands that are generated in a cascade process in high-quality optical resonators with Kerr nonlinearity, such as whispering gallery mode (WGM) resonators. For this purpose, the WGM resonator needs to be optically pumped at two frequencies matching its resonances. These two optical components can be one or several free spectral ranges (FSRs), equal to approximately 12 GHz, in this example, apart from each other, and can be easily derived from a monochromatic pump with an ordinary EOM (electro-optic modulation) operating at half the FSR frequency. With sufficient nonlinearity, an optical cascade process will convert the two pump frequencies into a comb-like structure extending many FSRs around the carrier frequency. This has a demonstratively efficient frequency conversion of this type with only a few milliwatt optical pump power. The concept of using Kerr nonlinearity in a resonator for non-degenerate wave mixing has been discussed before, but it was a common belief that this was a weak process requiring very high peak powers to be observable. It was not thought possible for this approach to compete with electro-optical modulators in CW applications, especially those at lower optical powers. By using the high-Q WGM resonators, the effective Kerr nonlinearity can be made so high that, using even weak seeding bands available from a conventional EOM, one can effectively multiply the optical sidebands, extending them into an otherwise inaccessible frequency range.
Multiplying Electrons With Diamond
NASA Technical Reports Server (NTRS)
2003-01-01
As researchers in the Space Communications Division of NASA s Glenn Research Center in 1992, Dr. Gerald Mearini, Dr. Isay Krainsky, and Dr. James Dayton made a secondary electron emission discovery that became the foundation for Mearini s company, GENVAC AeroSpace Corporation. Even after Mearini departed Glenn, then known as Lewis Research Center, his contact with NASA remained strong as he was awarded Small Business Innovation Research (SBIR) contracts to further develop his work. Mearini s work for NASA began with the investigation of diamond as a material for the suppression of secondary electron emissions. The results of his research were the opposite of what was expected diamond proved to be an excellent emitter rather than absorber. Mearini, Krainsky, and Dayton discovered that laboratory-grown diamond films can produce up to 45 electrons from a single incident electron. Having built an electron multiplier prototype at NASA, Mearini decided to start his own company to develop diamond structures usable in electron beam devices.
ERIC Educational Resources Information Center
Baroody, Arthur J.
2016-01-01
Six widely used US Grade 1 curricula do not adequately address the following three developmental prerequisites identified by a proposed learning trajectory for the meaningful learning of the subtraction-as-addition strategy (e.g., for 13-8 think "what + 8 = 13?"): (a) reverse operations (adding 8 is undone by subtracting 8); (b) common…
Color Addition and Subtraction Apps
NASA Astrophysics Data System (ADS)
Ruiz, Frances; Ruiz, Michael J.
2015-10-01
Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step in understanding mathematical representations of RGB color. Finally, color addition and subtraction are presented for the X11 colors from web design to illustrate yet another real-life application of color mixing.
Self-masking subtraction tomosynthesis
Chakraborty, D.P.; Yester, M.V.; Barnes, G.T.; Lakshminarayanan, A.V.
1984-01-01
The authors tested the image quality and dose savings of self-masking subtraction tomosynthesis (SST), which combines digital tomosynthesis with subtraction of a blurred self-mask. High-quality images of the inner ear of a head phantom were obtained at moderate dose savings. Although they were taken with linear motion, they did not exhibit the streaking due to off-fulcrum objects that is characteristic of conventional linear tomography. SST could reduce patient dose by a factor of at least 12 in examinations of the inner ear, and the mechanical aspects can be implemented with moderate modifications of existing instrumentation.
NULL convention floating point multiplier.
Albert, Anitha Juliette; Ramachandran, Seshasayanan
2015-01-01
Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069
NULL Convention Floating Point Multiplier
Ramachandran, Seshasayanan
2015-01-01
Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069
Multiply Strange Nuclear Systems
NASA Astrophysics Data System (ADS)
Schaffner, J.; Dover, C. B.; Gal, A.; Greiner, C.; Millener, D. J.; Stocker, H.
1994-10-01
We investigate the stability of multiply strange baryonic systems, in the context of a mean field approach obtained from an underlying set of phenomenological meson-baryon interactions. The coupling parameters which determine the conventional σ + ω mean fields (Hartree potentials) seen by various baryon species (N, Λ, Ξ) in the many-body system are constrained by reproducing the trend of observed binding energies of single particle (N, Λ, Ξ) states, as well as the energy per particle and density of non-strange nuclear matter. We also consider additional scalar (σ*) and vector (φ) fields which couple strongly to strange baryons. The couplings of these fields are adjusted to produce strong hyperon-hyperon interactions, as suggested by the data on ΛΛ hypernuclei. Extrapolating this approach to systems of large strangeness S, we find a broad class of objects composed of neutrons, protons, Λ‧s and Ξ‧s, which are stable against strong decay. In these systems, the presence of filled Λ orbitals blocks the strong decay ΞN → ΛΛ, leading to a strangeness fraction fs = |S|/A ≍1, density ρ ≍ (2 - 3) ρ0, and charge fraction fq in the range - 0.1
Effective switching frequency multiplier inverter
Su, Gui-Jia; Peng, Fang Z.
2007-08-07
A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.
"Subtractive" Bilingualism in Northern Belize.
ERIC Educational Resources Information Center
Rubinstein, Robert A.
"Subtractive" bilingualism in Northern Belize is analyzed based on an extension of a model by Wallace Lambert. The impact of English language instruction on Spanish speaking children in Corozal Town, the northernmost urban center in the British colony of Belize, Central America, is described. This description extends an earlier account of…
Color Addition and Subtraction Apps
ERIC Educational Resources Information Center
Ruiz, Frances; Ruiz, Michael J.
2015-01-01
Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…
Sky subtraction with fiber spectrographs
NASA Astrophysics Data System (ADS)
Lissandrini, C.; Cristiani, S.; La Franca, F.
1994-11-01
The sky-subtraction performance of multifiber spectrographs is discussed, analyzing in detail the case of the OPTOPUS system at the 3.6-m European Space Observatory (ESO) telescope at La Silla. A standard technique, based on flat fields obtained with a uniformly illuminated screen on the dome, provides poor results. A new method has been developed, using the (O I) emission line at 5577 A as a calibrator of the fiber transmittance, taking into account the diffuse light and the influence of each fiber on the adjacent ones, and correcting for the effects of the image distortions on the sky sampling. In this way the accuracy of the sky subtraction improves from 2%-8% to 1.3%-1.6%.
Bandpass x-ray diode and x-ray multiplier detector
Wang, C.L.
1982-09-27
An absorption-edge of an x-ray absorption filter and a quantum jump of a photocathode determine the bandpass characteristics of an x-ray diode detector. An anode, which collects the photoelectrons emitted by the photocathode, has enhanced amplification provided by photoelectron-multiplying means which include dynodes or a microchannel-plate electron-multiplier. Suppression of undesired high frequency response for a bandpass x-ray diode is provided by subtracting a signal representative of energies above the passband from a signal representative of the overall response of the bandpass diode.
Multipliers in weighted Sobolev spaces
NASA Astrophysics Data System (ADS)
Kusainova, L. K.
2005-08-01
Let X_1 and X_2 be a pair of Banach spaces of functions in \\Omega\\subset{\\mathbb R}^n. A multiplier from X_1 into X_2 is a function \\gamma on \\Omega such that \\gamma X_1=\\{\\gamma f,\\ f\\in X_1\\}\\subset X_2. By the norm \\Vert\\gamma\\Vert=\\Vert\\gamma\\Vert _{M(X_1\\to X_2)} one means the norm of the operator T(u)=\\gamma u, u\\in X_1. Conditions ensuring that a function \\gamma belongs to the multiplier classes M(W_1\\to W_2) and M(W\\to L) are found, where W and L are Sobolev and Lebesgue weighted spaces, respectively. Estimates of the norms of multipliers free from capacity characteristics are found. Special local maximal operators are introduced and significantly used.
Children's Use of Subtraction by Addition on Large Single-Digit Subtractions
ERIC Educational Resources Information Center
Peters, Greet; De Smedt, Bert; Torbeyns, Joke; Ghesquiere, Pol; Verschaffel, Lieven
2012-01-01
Subtractions of the type M - S = ? can be solved by various strategies, including subtraction by addition. In this study, we investigated children's use of subtraction by addition by means of reaction time analyses. We presented 106 third to sixth graders with 32 large non-tie single-digit problems in both subtraction (12 - 9 = .) and addition…
Dark energy from modified gravity with Lagrange multipliers
NASA Astrophysics Data System (ADS)
Capozziello, Salvatore; Matsumoto, Jiro; Nojiri, Shin'ichi; Odintsov, Sergei D.
2010-09-01
We study scalar-tensor theory, k-essence and modified gravity with Lagrange multiplier constraint which role is to reduce the number of degrees of freedom. Dark Energy cosmology of different types (ΛCDM, unified inflation with DE, smooth non-phantom/phantom transition epoch) is reconstructed in such models. It is demonstrated that presence of Lagrange multiplier simplifies the reconstruction scenario. It is shown that mathematical equivalence between scalar theory and F(R) gravity is broken due to presence of constraint. The cosmological evolution is defined by the second F(R) function dictated by the constraint. The convenient F(R) gravity sector is relevant for local tests. This opens the possibility to make originally non-realistic theory to be viable by adding the corresponding constraint. A general discussion on the role of Lagrange multipliers to make higher-derivative gravity canonical is developed.
Capacitance multiplier and filter synthesizing network
NASA Technical Reports Server (NTRS)
Kline, A. J. (Inventor)
1974-01-01
A circuit using a differential amplifier multiplies the capacitance of a discrete interating capacitor by (r sub 1 + R sub 2)/R sub 2, where R sub 1 and R sub 2 are values of discrete resistor coupling an input signal e sub 1 of the amplifier inputs. The output e sub 0 of the amplifier is fed back and added to the signal coupled by the resistor R sub 2 to the amplifier through a resistor of value R sub 1. A discrete resistor R sub x may be connected in series for a lag filter, and a discrete resistor may be connected in series with the capacitor for a lead-lag filter. Voltage dividing resistors R sub a and R sub b may be included in the feedback circuit of the amplifier output e sub o to independently adjust the circuit gain e sub i/e sub o.
Frequency multipliers for millimeter and submillimeter wavelengths
NASA Technical Reports Server (NTRS)
Raisanen, Antti V.
1992-01-01
All-solid-state local oscillators in the terahertz frequency range are especially needed for space-borne radio astronomy and remote sensing of the atmosphere. Because solid-state oscillators cannot yet produce the necessary local oscillator power at submillimeter wavelengths, frequency multipliers are needed. So far, submillimeter-wave frequency multipliers are mainly based on a whisker-contacted Schottky diode as the nonlinear element. This paper discusses the multiplier theory and tools for analysis and design of millimeter- and submillimeter-wave multipliers. Experimental work is reviewed. The Schottky diode model at submillimeter frequencies, use of Schottky multiplier chains versus direct higher-order multipliers, and the effect of cooling on Schottky diode multipliers are discussed. Alternative diodes such as the high electron mobility varactor, the barrier-intrinsic n(+) diode, the barrier-n-n(+) diode, the quantum well diode, and the single barrier varactor are discussed, with attention also given to their potential as submillimeter frequency multipliers.
Photoresistance analog multiplier has wide range
NASA Technical Reports Server (NTRS)
Hartenstein, R. G.
1965-01-01
Photoactivated bridge facilitates equal performance of analog multipliers over a wide frequency range. The multiplier operates from direct current to an upper frequency limited by either the light source or the closed-loop amplifier.
Switched-Capacitor Voltage Multiplier
NASA Technical Reports Server (NTRS)
Sridharan, Govind
1991-01-01
Dc-to-dc power converter multiplies input supply potential by factor of nearly 40. Design does not make use of transformers or inductors but effects voltage boost-up by capacitive energy transfer. Circuit primarily made up of banks of capacitors, connected by network of integrated-circuit relays. Converter functionally linear voltage amplifier with fixed gain figure. Bipolar in operation. Output fully floating, and excellent dc isolation between input and output terminals.
Planar diode multiplier chains for THz spectroscopy
NASA Technical Reports Server (NTRS)
Maiwald, Frank W.; Drouin, Brian J.; Pearson, John C.; Mehdi, Imran; Lewena, Frank; Endres, Christian; Winnewisser, Gisbert
2005-01-01
High-resolution laboratory spectroscopy is utilized as a diagnostic tool to determine noise and harmonic content of balanced [9]-[11] and unbalanced [12]-[14] multiplier designs. Balanced multiplier designs suppress unintended harmonics more than -20dB. Much smaller values were measured on unbalanced multipliers.
Superiority of photon subtraction to addition for entanglement in a multimode squeezed vacuum
NASA Astrophysics Data System (ADS)
Das, Tamoghna; Prabhu, R.; SenDe, Aditi; Sen, Ujjwal
2016-05-01
We investigate the entanglement patterns of photon-added and photon-subtracted four-mode squeezed vacuum states. Entanglements in different scenarios are analyzed by varying the number of photons added or subtracted in certain modes, which are referred to as the "player" modes, the others being "spectators." We find that the photon-subtracted state can give us higher entanglement than the photon-added state which is in contrast to the two-mode situation. We also study the logarithmic negativity of the two-mode reduced density matrix obtained from the four-mode state which again shows that the state after photon subtraction can possess higher entanglement than that of the photon-added state, and we then compare it to that of the two-mode squeezed vacuum state. Moreover, we examine the non-Gaussianity of the photon-added and photon-subtracted states to find that the rich features provided by entanglement cannot be captured by the measure of nonclassicality.
Addition and Subtraction, and Algorithms in General
ERIC Educational Resources Information Center
Fielker, David
2007-01-01
The juxtaposition of articles by Ian Thompson and Ian Sugarman in "MT202" on addition and subtraction respectively engendered some bemused thoughts in this author, who for some years has been sheltered from controversy by retirement. In this article, Fielker shares some thoughts on addition and subtraction raised by Thompson and Sugarman in their…
Contexts for Column Addition and Subtraction
ERIC Educational Resources Information Center
Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen
2011-01-01
In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by designing…
Digital subtraction angiography of the heart and lungs
Moodie, D.S.; Yiannikas, J.
1986-01-01
This book contains 12 chapters. Some of the chapter titles are: Physical Principles of Cardiac Digital Subtraction Angiography, The Use of Intravenous Digital Subtraction Angiography in Evaluating Patients with Complex Congenital Heart Disease, Exercise Intravenous Digital Subtraction Angiograpny, Cardiomyopathic and Cardiac Neoplastic Disease, Digital Subtraction Angiography in the Catheterization Laboratory, and Cardiac Digital Subtraction Angiography - Future Directions.
Synthesis algorithm of VLSI multipliers for ASIC
NASA Technical Reports Server (NTRS)
Chua, O. H.; Eldin, A. G.
1993-01-01
Multipliers are critical sub-blocks in ASIC design, especially for digital signal processing and communications applications. A flexible multiplier synthesis tool is developed which is capable of generating multiplier blocks for word size in the range of 4 to 256 bits. A comparison of existing multiplier algorithms is made in terms of speed, silicon area, and suitability for automated synthesis and verification of its VLSI implementation. The algorithm divides the range of supported word sizes into sub-ranges and provides each sub-range with a specific multiplier architecture for optimal speed and area. The algorithm of the synthesis tool and the multiplier architectures are presented. Circuit implementation and the automated synthesis methodology are discussed.
Tracking of Human Groups Using Subtraction Stereo
NASA Astrophysics Data System (ADS)
Hoshikawa, Yuma; Hashimoto, Yuki; Moro, Alessandro; Terabayashi, Kenji; Umeda, Kazunori
In this paper, we propose a method for tracking groups of people using three-dimensional (3D) feature points obtained with use of the Kanade-Lucas-Tomasi feature tracker (KLT) method and a stereo camera system called “Subtraction stereo”. The tracking system using subtraction stereo, which focuses its stereo matching algorithm to foreground regions obtained by background subtraction, is realized using Kalman filter based tracker. The effectiveness of the proposed method is verified using 3D scenes of people walking, which are difficult to track.
Optimization of background subtraction for image enhancement
NASA Astrophysics Data System (ADS)
Venetsky, Larry; Boczar, Ross; Lee-Own, Robert
2013-05-01
Analysis of foreground objects in scenery via image processing often involves a background subtraction process. This process aims to improve blob (connected component) content in the image. Quality blob content is often needed for defining regions of interest for object recognition and tracking. Three techniques are examined which optimize the background to be subtracted - genetic algorithm, an analytic solution based on convex optimization, and a related application of the CVX solver toolbox. These techniques are applied to a set of images and the results are compared. Additionally, a possible implementation architecture that uses multiple optimization techniques with subsequent arbitration to produce the best background subtraction is considered.
The utility of digital subtraction arteriography in peripheral vascular disease.
Kubal, W S; Crummy, A B; Turnipseed, W D
1983-01-01
Digital subtraction angiography (DSA), whether used in conjunction with intravenous or intraarterial injection techniques, has an established role in evaluation of peripheral vascular disease. Use of DSA can reduce the time, cost, and patient discomfort of the standard arteriographic study. While it is limited by field size and patient cooperation in some instances, the utility of noninvasive imaging using intravenous DSA and the added anatomic detail of intraarterial DSA for roadmapping and delineation of small distal vessels provide the basis for future integration of standard arteriographic and DSA methods in assessment of peripheral vascular disease. PMID:6228296
Shaw, C G; Plewes, D B
1986-08-01
The pulsed-injection method for measuring the velocity of blood flow in intraarterial digital subtraction angiography is described. With this technique, contrast material is injected at a pulsing frequency as high as 15 Hz, so that two or more boluses can be imaged simultaneously. The velocity of flow is determined by measuring the spacing between the boluses and multiplying it by the pulsing frequency. Results of tests with phantoms correlate well with flow measurements obtained with a graduated cylinder for velocities ranging from 8 to 60 cm/sec. The potential of the method for time-dependent velocity measurement has been demonstrated with simulated pulsatile flows. PMID:3523598
Compact, harmonic multiplying gyrotron amplifiers
Guo, H.Z.; Granatstein, V.L.; Antonsen, T.M. Jr.; Levush, B.; Tate, J.; Chen, S.H.
1995-12-31
A compact, harmonic multiplying gyrotron traveling wave amplifier is being developed. The device is a three-stage tube with the output section running as a fourth harmonic gyro-TWT, the input section running as a fundamental gyro-TWT, and the middle operating at the second harmonic of the cyclotron frequency. Radiation is suppressed by servers between the sections. The operating beam of the tube is produced by a magnetron injection gun (MIG). A TE{sub 0n} mode selective interaction circuit consisting of mode converters and a filter waveguide is employed for both input and output sections to solve the mode competition problem, which is pervasive in gyro-TWT operation. The input section has an input coupler designed as a TE{sub 0n} mode launcher. It excites a signal at the fundamental cyclotron frequency (17.5 GHz), which is amplified in the first TWT interaction region. So far the device is similar to a two-stage harmonic gyro-TWT. The distinction is that in the three-stage device the second section will be optimized not for output power but for fourth harmonic bunching of the beam. A gyroklystron amplifier has also been designed. The configuration is similar to the gyro-TWT but with the traveling wave interaction structures replaced by mode selective special complex cavities. Cold test results of the wideband input coupler and the TE{sub 0n} mode selective interaction circuit have been obtained.
Serial multiplier arrays for parallel computation
NASA Technical Reports Server (NTRS)
Winters, Kel
1990-01-01
Arrays of systolic serial-parallel multiplier elements are proposed as an alternative to conventional SIMD mesh serial adder arrays for applications that are multiplication intensive and require few stored operands. The design and operation of a number of multiplier and array configurations featuring locality of connection, modularity, and regularity of structure are discussed. A design methodology combining top-down and bottom-up techniques is described to facilitate development of custom high-performance CMOS multiplier element arrays as well as rapid synthesis of simulation models and semicustom prototype CMOS components. Finally, a differential version of NORA dynamic circuits requiring a single-phase uncomplemented clock signal introduced for this application.
Keynesian multiplier versus velocity of money
NASA Astrophysics Data System (ADS)
Wang, Yougui; Xu, Yan; Liu, Li
2010-08-01
In this paper we present the relation between Keynesian multiplier and the velocity of money circulation in a money exchange model. For this purpose we modify the original exchange model by constructing the interrelation between income and expenditure. The random exchange yields an agent's income, which along with the amount of money he processed determines his expenditure. In this interactive process, both the circulation of money and Keynesian multiplier effect can be formulated. The equilibrium values of Keynesian multiplier are demonstrated to be closely related to the velocity of money. Thus the impacts of macroeconomic policies on aggregate income can be understood by concentrating solely on the variations of money circulation.
Minimal subtraction and momentum subtraction in quantum chromodynamics at two-loop order
Braaten, E.; Leveille, J.P.
1981-09-01
The momentum-subtraction coupling constant ..cap alpha../sub MOM/ yields consistently smaller one-loop corrections to many quantum-chromodynamics (QCD) processes than the minimal-subtraction couplings ..cap alpha../sub MS/ and ..cap alpha../sub M/S. By shifting the renormalization scale ..mu.. of ..cap alpha../sub MS/(..mu..), we obtain a minimal-subtraction coupling with the same small one-loop corrections. It is shown, by studying the effective charges of QCD, that at two-loop order this coupling constant will continue to yield corrections to physical quantities that are comparable to those obtained by momentum subtraction. We also introduce a momentum-subtraction scheme which treats the triple-gluon, quark, and ghost vertices equally at one-loop order and is more convenient for higher-order calculations than the MOM scheme.
Open-loop digital frequency multiplier
NASA Technical Reports Server (NTRS)
Moore, R. C.
1977-01-01
Monostable multivibrator is implemented by using digital integrated circuits where multiplier constant is too large for conventional phase-locked-loop integrated circuit. A 400 Hz clock is generated by divide-by-N counter from 1 Hz timing reference.
Framework Resources Multiply Computing Power
NASA Technical Reports Server (NTRS)
2010-01-01
As an early proponent of grid computing, Ames Research Center awarded Small Business Innovation Research (SBIR) funding to 3DGeo Development Inc., of Santa Clara, California, (now FusionGeo Inc., of The Woodlands, Texas) to demonstrate a virtual computer environment that linked geographically dispersed computer systems over the Internet to help solve large computational problems. By adding to an existing product, FusionGeo enabled access to resources for calculation- or data-intensive applications whenever and wherever they were needed. Commercially available as Accelerated Imaging and Modeling, the product is used by oil companies and seismic service companies, which require large processing and data storage capacities.
Children's Misconceptions about the Multidigit Subtraction Algorithm.
ERIC Educational Resources Information Center
Cauley, Kathleen M.
This study probed children's reasoning about both correct and incorrect but plausible statements of hypothetical children concerning the concepts of subtraction, with the intention of examining misconceptions in greater depth. Eight third graders, 14 fourth graders, and 14 fifth graders were interviewed individually to assess their understanding…
Diagnosis of Subtraction Bugs Using Bayesian Networks
ERIC Educational Resources Information Center
Lee, Jihyun; Corter, James E.
2011-01-01
Diagnosis of misconceptions or "bugs" in procedural skills is difficult because of their unstable nature. This study addresses this problem by proposing and evaluating a probability-based approach to the diagnosis of bugs in children's multicolumn subtraction performance using Bayesian networks. This approach assumes a causal network relating…
Verification of IEEE Compliant Subtractive Division Algorithms
NASA Technical Reports Server (NTRS)
Miner, Paul S.; Leathrum, James F., Jr.
1996-01-01
A parameterized definition of subtractive floating point division algorithms is presented and verified using PVS. The general algorithm is proven to satisfy a formal definition of an IEEE standard for floating point arithmetic. The utility of the general specification is illustrated using a number of different instances of the general algorithm.
Children's Profiles of Addition and Subtraction Understanding
ERIC Educational Resources Information Center
Canobi, Katherine H.
2005-01-01
The current research explored children's ability to recognize and explain different concepts both with and without reference to physical objects so as to provide insight into the development of children's addition and subtraction understanding. In Study 1, 72 7- to 9-year-olds judged and explained a puppet's activities involving three conceptual…
Polygon Subtraction in 2 or 3 Dimensions
Wilson, John E.
2013-10-01
When searching for computer code to perform the ubiquitous task of subtracting one polygon from another, it is difficult to find real examples and detailed explanations. This paper outlines the step-by-step process necessary to accomplish this basic task.
Cosmological models with Lagrange multiplier field
NASA Astrophysics Data System (ADS)
Gao, Changjun; Gong, Yan; Wang, Xin; Chen, Xuelei
2011-08-01
We first consider the Einstein-aether theory with a gravitational coupling and a Lagrange multiplier field, and then consider the non-minimally coupled quintessence field theory with Lagrange multiplier field. We study the influence of the Lagrange multiplier field on these models. We show that the energy density evolution of the Einstein-aether field and the quintessence field are significantly modified. The energy density of the Einstein-aether is nearly a constant during the entire history of the Universe. The energy density of the quintessence field can also be kept nearly constant in the matter dominated Universe, or even exhibit a phantom-like behavior for some models. This suggests a possible dynamical origin of the cosmological constant or dark energy. Further more, for the canonical quintessence in the absence of gravitational coupling, we find that the quintessence scalar field can play the role of cold dark matter with the introduction of a Lagrange multiplier field. We conclude that the Lagrange multiplier field could play a very interesting and important role in the construction of cosmological models.
QCD Condensates and Holographic Wilson Loops for Asymptotically AdS Spaces
Quevedo, R. Carcasses; Goity, Jose L.; Trinchero, Roberto C.
2014-02-01
The minimization of the Nambu-Goto (NG) action for a surface whose contour defines a circular Wilson loop of radius a placed at a finite value of the coordinate orthogonal to the border is considered. This is done for asymptotically AdS spaces. The condensates of dimension n = 2, 4, 6, 8, and 10 are calculated in terms of the coefficients in the expansion in powers of the radius a of the on-shell subtracted NG action for small a->0. The subtraction employed is such that it presents no conflict with conformal invariance in the AdS case and need not introduce an additional infrared scale for the case of confining geometries. It is shown that the UV value of the gluon condensates is universal in the sense that it only depends on the first coefficients of the difference with the AdS case.
Digital subtraction angiography in extremity trauma
Goodman, P.C.; Jeffrey, R.B. Jr.; Brant-Zawadzki, M.
1984-10-01
Digital subtraction angiography (DSA) may have considerable impact on the work-up of patients who have suffered trauma. The angiographic evaluation of vascular injuries can be accomplished rapidly and with minimal catheter use and manipulation, which is particularly important for those critically ill patients who have significant immobility because of multiple fractures. The authors retrospectively reviewed the digital subtraction angiograms in 50 consecutive cases of extremity trauma. The quality of the images in 44 of these permitted a confident diagnosis, the accuracy of which was confirmed by surgical or clinical follow-up. DSA reduces the time required to perform the procedure, the amount of contrast material injected, patient discomfort, and film cost. Its major disadvantage is the limited field size of the image intensifier.
WIDE BAND REGENERATIVE FREQUENCY DIVIDER AND MULTIPLIER
Laine, E.F.
1959-11-17
A regenerative frequency divider and multiplier having wide band input characteristics is presented. The circuit produces output oscillations having frequencies related by a fixed ratio to input oscillations over a wide band of frequencies. In accomplishing this end, the divider-multiplier includes a wide band input circuit coupled by mixer means to a wide band output circuit having a pass band related by a fixed ratio to that of the input circuit. A regenerative feedback circuit derives a fixed frequency ratio feedback signal from the output circuit and applies same to the mixer means in proper phase relation to sustain fixed frequency ratio oscillations in the output circuit.
Liquid-Crystal-Television Image Subtracters
NASA Technical Reports Server (NTRS)
Chao, Tien-Hsin; Liu, Hua-Kuang
1988-01-01
Two image-subtraction systems from output images that show differences between input images of two objects. First: differences appear as bright regions in otherwise dark output image. Second: differences and similarities shown by colors. All parts of two images processed simultaneously by optical components only; digital electronic processing of data not required. Concept offers potential for rapid, inexpensive comparison of images in such applications as automatic inspection, medical diagnosis, and robotic vision.
Tomosynthesis applied to digital subtraction angiography
Kruger, R.A.; Sedaghati, M.; Roy, D.G.; Liu, P.; Nelson, J.A.; Kubal, W.; Del Rio, P.
1984-09-01
This extension of the author's previous work on tomographic digital subtraction angiography (DSA) describes the theory of tomosynthetic DSA image reconstruction techniques. In addition to developing the resolution limits resulting from x-ray exposure length and image intensifier field curvature, the authors describe one method of image formation and show tomosynthetic DSA images of animal and human anatomy. Methods for improving the present technique are discussed.
Novel embossed radiography system utilizing energy subtraction
NASA Astrophysics Data System (ADS)
Osawa, Akihiro; Sato, Eiichi; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Nagao, Jiro; Abderyim, Purkhet; Tanaka, Etsuro; Izumisawa, Mitsuru; Ogawa, Akira; Sato, Shigehiro
2008-08-01
Digital subtraction is useful for carrying out embossed radiography by shifting an x-ray source, and energy subtraction is an important technique for imaging target region by deleting unnecessary region in vivo. X-ray generator had a 100-μm-focus tube, energy subtraction was performed at tube voltages of 40 and 60 kV, and a 3.0-mm-thick aluminum filter was used to absorb low-photon-energy bremsstrahlung x-rays. Embossed radiography was achieved with cohesion imaging using a flat panel detector (FPD) with pixel sizes of 48×48 μm, and the shifting distance of the x-ray source in horizontal direction and the distance between the x-ray source and the FPD face were 5.0 mm and 1.0 m, respectively. At a tube voltage of 60 kV and a tube current of 0.50 mA, x-ray intensities without filtering and with filtering were 307 and 28.4 μGy/s, respectively, at 1.0 m from the source. In embossed radiography of non-living animals, the spatial resolution measured using a lead test chart was approximately 70 μm, and we observed embossed images of fine bones, soft tissues, and coronary arteries of approximately 100 μm.
Subtractive Structural Modification of Morpho Butterfly Wings.
Shen, Qingchen; He, Jiaqing; Ni, Mengtian; Song, Chengyi; Zhou, Lingye; Hu, Hang; Zhang, Ruoxi; Luo, Zhen; Wang, Ge; Tao, Peng; Deng, Tao; Shang, Wen
2015-11-11
Different from studies of butterfly wings through additive modification, this work for the first time studies the property change of butterfly wings through subtractive modification using oxygen plasma etching. The controlled modification of butterfly wings through such subtractive process results in gradual change of the optical properties, and helps the further understanding of structural optimization through natural evolution. The brilliant color of Morpho butterfly wings is originated from the hierarchical nanostructure on the wing scales. Such nanoarchitecture has attracted a lot of research effort, including the study of its optical properties, its potential use in sensing and infrared imaging, and also the use of such structure as template for the fabrication of high-performance photocatalytic materials. The controlled subtractive processes provide a new path to modify such nanoarchitecture and its optical property. Distinct from previous studies on the optical property of the Morpho wing structure, this study provides additional experimental evidence for the origination of the optical property of the natural butterfly wing scales. The study also offers a facile approach to generate new 3D nanostructures using butterfly wings as the templates and may lead to simpler structure models for large-scale man-made structures than those offered by original butterfly wings. PMID:26397977
The Multicultural Factor: A Curriculum Multiplier.
ERIC Educational Resources Information Center
Turkovich, Marilyn; Mueller, Peggy
1989-01-01
Urges that an evaluative attitude be taken concerning curricular efforts to foster multicultural education. Suggests expanding the primary school curriculum, defining multicultural education, and multiplying the effects of a lesson by linking multicultural activities with concepts already being taught. Provides illustrative activities to integrate…
Cleaning of contaminated channel electron multiplier arrays.
NASA Technical Reports Server (NTRS)
Harlow, F. E.; Hunter, W. R.
1972-01-01
Polymerized organic materials found in vacuum systems frequently contaminate the individual channels (which can be as small as 15 microns) of an oil-pumped channel electron multiplier array used as a vacuum UV- to visible-radiation conversion device. It is shown that exposure to an oxygen plasma is an effective means of decontaminating the channels, thereby restoring the sensitivity of the device.
Temperature Effects in Varactors and Multipliers
NASA Technical Reports Server (NTRS)
East, J.; Mehdi, Imran
2001-01-01
Varactor diode multipliers are a critical part of many THz measurement systems. The power and efficiencies of these devices limit the available power for THz sources. Varactor operation is determined by the physics of the varactor device and a careful doping profile design is needed to optimize the performance. Higher doped devices are limited by junction breakdown and lower doped structures are limited by current saturation. Higher doped structures typically have higher efficiencies and lower doped structures typically have higher powers at the same operating frequency and impedance level. However, the device material properties are also a function of the operating temperature. Recent experimental evidence has shown that the power output of a multiplier can be improved by cooling the device. We have used a particle Monte Carlo simulation to investigate the temperature dependent velocity vs. electric field in GaAs. This information was then included in a nonlinear device circuit simulator to predict multiplier performance for various temperatures and device designs. This paper will describe the results of this analysis of temperature dependent multiplier operation.
NASA Astrophysics Data System (ADS)
Lee, Mike M.; Cho, Byung Lok
2001-11-01
In this paper, we proposed a new First Partial product Addition (FPA) architecture with new compressor (or parallel counter) to CSA tree built in the process of adding partial product for improving speed in the fast parallel multiplier to improve the speed of calculating partial product by about 20% compared with existing parallel counter using full Adder. The new circuit reduces the CLA bit finding final sum by N/2 using the novel FPA architecture. A 5.14ns of multiplication speed of the 16X16 multiplier is obtained using 0.25um CMOS technology. The architecture of the multiplier is easily opted for pipeline design and demonstrates high speed performance.
Subtraction threshold for an isotropic fluorescence emission difference microscope
NASA Astrophysics Data System (ADS)
Wang, Nan; Kobayashi, Takayoshi
2015-12-01
Isotropic fluorescence emission difference microscopy proposed recently provides a simple method to enhance the spatial resolution in three-dimensions (3D) for fluorescence imaging. However, the subtraction threshold to achieve the condition for appropriately resolving the sample in 3D have not been studied. Then the subtraction factors used in this type of microscopes are still experientially chosen. Based on vector diffraction theory and a 3D numerical model developed here, the subtraction threshold is numerically investigated for the isotropic fluorescence subtraction microscopy. The subtraction factors and peak intensities at the threshold are obtained and comparied both in lateral and axial planes for achieving most appropriate subtraction and inspecting the isotropic characteristic. The effects of radius ratios of implemented 0-π annular phase plate for generating three dimensional donut spot on the subtracted resolution, peak intensity and negative sidebands are also discussed.
Podoshvedov, S. A.
2011-04-15
A method to generate Schroedinger cat states in free propagating optical fields based on the use of displaced states (or displacement operators) is developed. Some optical schemes with photon-added coherent states are studied. The schemes are modifications of the general method based on a sequence of displacements and photon additions or subtractions adjusted to generate Schroedinger cat states of a larger size. The effects of detection inefficiency are taken into account.
ERIC Educational Resources Information Center
UCLA IDEA, 2012
2012-01-01
Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher, the better students…
Integrated optic vector-matrix multiplier
Watts, Michael R.
2011-09-27
A vector-matrix multiplier is disclosed which uses N different wavelengths of light that are modulated with amplitudes representing elements of an N.times.1 vector and combined to form an input wavelength-division multiplexed (WDM) light stream. The input WDM light stream is split into N streamlets from which each wavelength of the light is individually coupled out and modulated for a second time using an input signal representing elements of an M.times.N matrix, and is then coupled into an output waveguide for each streamlet to form an output WDM light stream which is detected to generate a product of the vector and matrix. The vector-matrix multiplier can be formed as an integrated optical circuit using either waveguide amplitude modulators or ring resonator amplitude modulators.
Perdurance of multiply connected de Sitter space
NASA Astrophysics Data System (ADS)
González-Díaz, Pedro F.
1999-06-01
This paper deals with a study of the effects that spherically symmetric first-order metric perturbations and vacuum quantum fluctuations have on the stability of the multiply connected de Sitter spacetime recently proposed by Gott and Li. It is the main conclusion of this study that although such a spacetime is stable to the classical metric perturbations for any size of the nonchronal region, it is only stable against the quantum fluctuations of vacuum if the size of the multiply connected region is of the order of the Planck scale. Therefore, boundary conditions for the state of the universe based on the notion that the universe created itself in a regime where closed timelike curves were active and stable still appear to be physically and philosophically well supported as are those boundary conditions relying on the notion that the universe was created out of nothing.
Low-Jitter Digital Rate Multiplier
NASA Technical Reports Server (NTRS)
Katz, Richard B.; Rakow, Glenn P.
1993-01-01
Jitter in digital rate multiplier reduced by improved method involving use of two slightly different minor clock periods. Original application to divide measured period of spin of spacecraft into large number of equal subintervals, by counting cycles of master oscillator running at high frequency. Method also used to reduce jitter in other situations necessary to generate equal subintervals from synchronizing clock signal of arbitrary period. Particularly valuable in situations where synchronizing signals lost temporarily and where drift in analog circuit unacceptable.
Multiply manifolded molten carbonate fuel cells
Krumpelt, M.; Roche, M.F.; Geyer, H.K.; Johnson, S.A.
1994-08-01
This study consists of research and development activities related to the concept of a molten carbonate fuel cell (MCFC) with multiple manifolds. Objective is to develop an MCFC having a higher power density and a longer life than other MCFC designs. The higher power density will result from thinner gas flow channels; the extended life will result from reduced temperature gradients. Simplification of the gas flow channels and current collectors may also significantly reduce cost for the multiply manifolded MCFC.
Automobile Industry Retail Price Equivalent and Indirect Cost Multipliers
This report develops a modified multiplier, referred to as an indirect cost (IC) multiplier, which specifically evaluates the components of indirect costs that are likely to be affected by vehicle modifications associated with environmental regulation. A range of IC multipliers a...
Lagrange multipliers in theories of gravitation
Kichenassamy, S.
1986-05-01
In gravitatinal theories, P-italic-variation (independepent variation of metric and connection) and H-variation (variation of the metric alone) may be reconciled through C-italic-variation (use of Lagrange multipliers ..lambda.. in P-italic-variation). We extend C-italic-variation to fields coupled with gravitational field and elucidate the cases of vanishing ..lambda... We show that the interpretation of ..lambda.. as constraint reaction forces sheds new light on the structure of these theories; we are thus led to question the necessary of relating torsion to spin, and as an alternative to the theory of Dirac particles in Einstein-Cartan space-time, we propose in a Lorentzian space-time a theory in which Lagrange multipliers corresponding to the vanishing of torsion lead to the symmetrization of canonical energy-momentum tensor and avoid the Heisenberg-Pauli-type terms. Lagrange multipliers also serve to reduce the fourth-order differential equations of gravitational quadratic Lagrangians to second-order ones with additional field variables (a scalar P-italic and a traceless tensor P-italic-tilde/sub i//sub j/); this reduction helps to make precise the compatibility of these theories with General Relativity. Simple derivations are also given for Chern and Euler characteristics c-italic/sub 2/ and /sub Chi//sub 2/, and for other identities.
Total Variation Regularized Tensor RPCA for Background Subtraction From Compressive Measurements.
Cao, Wenfei; Wang, Yao; Sun, Jian; Meng, Deyu; Yang, Can; Cichocki, Andrzej; Xu, Zongben
2016-09-01
Background subtraction has been a fundamental and widely studied task in video analysis, with a wide range of applications in video surveillance, teleconferencing, and 3D modeling. Recently, motivated by compressive imaging, background subtraction from compressive measurements (BSCM) is becoming an active research task in video surveillance. In this paper, we propose a novel tensor-based robust principal component analysis (TenRPCA) approach for BSCM by decomposing video frames into backgrounds with spatial-temporal correlations and foregrounds with spatio-temporal continuity in a tensor framework. In this approach, we use 3D total variation to enhance the spatio-temporal continuity of foregrounds, and Tucker decomposition to model the spatio-temporal correlations of video background. Based on this idea, we design a basic tensor RPCA model over the video frames, dubbed as the holistic TenRPCA model. To characterize the correlations among the groups of similar 3D patches of video background, we further design a patch-group-based tensor RPCA model by joint tensor Tucker decompositions of 3D patch groups for modeling the video background. Efficient algorithms using the alternating direction method of multipliers are developed to solve the proposed models. Extensive experiments on simulated and real-world videos demonstrate the superiority of the proposed approaches over the existing state-of-the-art approaches. PMID:27305675
Spectral amplitude coding OCDMA using and subtraction technique.
Hasoon, Feras N; Aljunid, S A; Samad, M D A; Abdullah, Mohamad Khazani; Shaari, Sahbudin
2008-03-20
An optical decoding technique is proposed for a spectral-amplitude-coding-optical code division multiple access, namely, the AND subtraction technique. The theory is being elaborated and experimental results have been done by comparing a double-weight code against the existing code, Hadamard. We have proved that the and subtraction technique gives better bit error rate performance than the conventional complementary subtraction technique against the received power level. PMID:18709073
Language, visual working memory, and dot subtraction: What counts?
Briere, Jennifer L; Campbell, Jamie I D
2016-03-01
To investigate cognitive factors affecting subtraction of visual objects, we adapted the dot subtraction task developed by Pica, Lemer, Izard, and Dehaene (2004), who used it to investigate calculation by the Mundurukú, an indigene group in Brazil that has a limited number word vocabulary. In the dot subtraction task, briefly displayed arrays of moving dots are used to represent the quantities for subtraction. We tested 40 Canadian university students' dot enumeration, Arabic digit subtraction, visual working memory, and performance on the dot subtraction task with dot display durations of 2, 1.5, 1, and .5 s. In the 2 s condition, error rates were uniformly low, whereas in the .5 s condition, error rates increased sharply as the minuend increased from 4 to 8, as was observed with the Mundurukú. Individual differences in dot subtraction accuracy were predicted by dot enumeration skill with longer dot display durations but were predicted by visual working memory efficiency with shorter durations. Pica et al. (2004) attributed the Mundurukú participants' very poor subtraction to the absence of counting words, but our results show that a shift to reliance on visual working memory is a nonlinguistic factor that comes into play in the dot subtraction task when time to encode the dot arrays is limited. (PsycINFO Database Record PMID:26372056
Watanabe, Ryo; Ogawa, Masato; Mituzono, Hiroki; Aoki, Takahiro; Hayano, Mizuho; Watanabe, Yuka
2010-08-20
In optimizing exposures, it is very important to evaluate the impact of image noise on image quality. To realize this, there is a need to evaluate how much image noise will make the subject disease invisible. But generally it is very difficult to shoot images of different quality in a clinical examination. Thus, a method to create a noise addition image by adding the image noise to raw data has been reported. However, this approach requires a special system, so it is difficult to implement in many facilities. We have invented a method to easily create a noise addition image by using the water phantom and image add-subtract software that accompanies the device. To create a noise addition image, first we made a noise image by subtracting the water phantom with different SD. A noise addition image was then created by adding the noise image to the original image. By using this method, a simulation image with intergraded SD can be created from the original. Moreover, the noise frequency component of the created noise addition image is as same as the real image. Thus, the relationship of image quality to SD in the clinical image can be evaluated. Although this method is an easy method of LDSI creation on image data, a noise addition image can be easily created by using image addition and subtraction software and water phantom, and this can be implemented in many facilities. PMID:20953102
Digital subtraction angiography: overview of technical principles.
Harrington, D P; Boxt, L M; Murray, P D
1982-10-01
The rapid development of equipment for digital subtraction angiography (DSA) has created a new diagnostic imaging method, the limits of which have not been scientifically determined. Yet through aggressive marketing, the technique is already beginning to permeate radiologic practice. The radiologist requires technical understanding of the instrumentation for informed judgment on clinical applications. DSA depends on the mating of high-resolution image-intensifier and television technology with computerized information manipulation and storage. In this overview, the individual components of the system are analyzed, from the generator to the image intensifier to the television system to the associated computer. By examining the role of each component, the current limitations and the areas of possible future development of DSA can be understood. This provides a basis for dealing with current technology and for evaluating the rapid technological changes that will occur over the next few years. PMID:6751053
Systolic multipliers for finite fields GF(2 exp m)
NASA Technical Reports Server (NTRS)
Yeh, C.-S.; Reed, I. S.; Truong, T. K.
1984-01-01
Two systolic architectures are developed for performing the product-sum computation AB + C in the finite field GF(2 exp m) of 2 exp m elements, where A, B, and C are arbitrary elements of GF(2 exp m). The first multiplier is a serial-in, serial-out one-dimensional systolic array, while the second multiplier is a parallel-in, parallel-out two-dimensional systolic array. The first multiplier requires a smaller number of basic cells than the second multiplier. The second multiplier needs less average time per computation than the first multiplier, if a number of computations are performed consecutively. To perform single computations both multipliers require the same computational time. In both cases the architectures are simple and regular and possess the properties of concurrency and modularity. As a consequence, they are well suited for use in VLSI systems.
Pipeline active filter utilizing a booth type multiplier
NASA Technical Reports Server (NTRS)
Nathan, Robert (Inventor)
1987-01-01
Multiplier units of the modified Booth decoder and carry-save adder/full adder combination are used to implement a pipeline active filter wherein pixel data is processed sequentially, and each pixel need only be accessed once and multiplied by a predetermined number of weights simultaneously, one multiplier unit for each weight. Each multiplier unit uses only one row of carry-save adders, and the results are shifted to less significant multiplier positions and one row of full adders to add the carry to the sum in order to provide the correct binary number for the product Wp. The full adder is also used to add this product Wp to the sum of products .SIGMA.Wp from preceding multiply units. If m.times.m multiplier units are pipelined, the system would be capable of processing a kernel array of m.times.m weighting factors.
Electrical Characterization of Silicon Photo-Multipliers
NASA Astrophysics Data System (ADS)
Mwathi, John; Woody, Craig; Stoll, Sean
2014-09-01
Silicon photo-multipliers (SiPM) also known as Multi-Pixel Photon Counters (MPPC) are single photon sensitive, semiconductor devices built from Avalanche Photo Diodes (APDs) working in the Geiger mode. The SiPM detectors provide an attractive solution for the detection of signals with low numbers of photons and are suitable candidates to replace Vacuum Photo-Multiplier Tubes (PMTs). They offer advantages over both PMTs and the APDs, including compactness, insensitivity to magnetic fields, high gain (105), ability to be operated at moderate bias voltage (normally lower than 100 volts), and excellent timing properties these characteristics make them suitable for applications in several fields of high energy physics and medical imaging. At Brookhaven National Laboratory, silicon photo-multipliers have been suggested as the readout device to be used in the upgraded sPHENIX in the area of high-energy physics calorimetry and future Positron Emission Tomography (PET) medical imaging systems. Despite all these advantages SiPMs have several drawbacks such as crosstalk, after pulse rate and dark-count rate, exposure to radiation damages the detector and greatly affects its efficiency. We characterized SiPMs of different pixel sizes from SensL and Hamamatsu to determine the SiPM's performance and which of these detectors would best be suited for application. We characterized these SiPM samples using lab instruments including a Picometer and a digital oscilloscope. A Lab view program controlling and reading out the Keithley Picometer via an IEEE-GPIB interface was developed to automate the dark current as a function of bias voltage measurement. Silicon photo-multipliers (SiPM) also known as Multi-Pixel Photon Counters (MPPC) are single photon sensitive, semiconductor devices built from Avalanche Photo Diodes (APDs) working in the Geiger mode. The SiPM detectors provide an attractive solution for the detection of signals with low numbers of photons and are suitable candidates
Sturm, C.; Soni, A.; Aoki, Y.; Christ, N. H.; Izubuchi, T.; Sachrajda, C. T. C.
2009-07-01
We extend the Rome-Southampton regularization independent momentum-subtraction renormalization scheme (RI/MOM) for bilinear operators to one with a nonexceptional, symmetric subtraction point. Two-point Green's functions with the insertion of quark bilinear operators are computed with scalar, pseudoscalar, vector, axial-vector and tensor operators at one-loop order in perturbative QCD. We call this new scheme RI/SMOM, where the S stands for 'symmetric'. Conversion factors are derived, which connect the RI/SMOM scheme and the MS scheme and can be used to convert results obtained in lattice calculations into the MS scheme. Such a symmetric subtraction point involves nonexceptional momenta implying a lattice calculation with substantially suppressed contamination from infrared effects. Further, we find that the size of the one-loop corrections for these infrared improved kinematics is substantially decreased in the case of the pseudoscalar and scalar operator, suggesting a much better behaved perturbative series. Therefore it should allow us to reduce the error in the determination of the quark mass appreciably.
A Proposed Instructional Theory for Integer Addition and Subtraction
ERIC Educational Resources Information Center
Stephan, Michelle; Akyuz, Didem
2012-01-01
This article presents the results of a 7th-grade classroom teaching experiment that supported students' understanding of integer addition and subtraction. The experiment was conducted to test and revise a hypothetical learning trajectory so as to propose a potential instructional theory for integer addition and subtraction. The instructional…
Evolutionary Processes in the Development of Errors in Subtraction Algorithms
ERIC Educational Resources Information Center
Fernandez, Ricardo Lopez; Garcia, Ana B. Sanchez
2008-01-01
The study of errors made in subtraction is a research subject approached from different theoretical premises that affect different components of the algorithmic process as triggers of their generation. In the following research an attempt has been made to investigate the typology and nature of errors which occur in subtractions and their evolution…
Developing a Model to Support Students in Solving Subtraction
ERIC Educational Resources Information Center
Murdiyani, Nila Mareta; Zulkardi; Putri, Ratu Ilma Indra; van Eerde, Dolly; van Galen, Frans
2013-01-01
Subtraction has two meanings and each meaning leads to the different strategies. The meaning of "taking away something" suggests a direct subtraction, while the meaning of "determining the difference between two numbers" is more likely to be modeled as indirect addition. Many prior researches found that the second meaning and…
When Should We Teach Regrouping in Addition and Subtraction.
ERIC Educational Resources Information Center
Engelhardt, Jon M.; Usnick, Virginia
1991-01-01
Presented are the results of two pilot studies about multidigit addition and subtraction. The results are discussed in relation to possible alternative sequences in the teaching of addition and subtraction and the relationship between basic fact mastery and numeration concept attainment. (CW)
Fostering First-Graders' Fluency with Basic Subtraction Combinations
ERIC Educational Resources Information Center
Baroody, Arthur J.; Purpura, David J.; Eiland, Michael D.; Reid, Erin E.
2012-01-01
Subtraction combinations are particularly challenging for children to learn (Kraner, 1980; Smith, 1921; see Cowan, 2003, for a review). This study examines whether the group of children receiving the "experimental subtraction-as-addition" training outperform the "control" group, which received training on a different reasoning strategy involving…
ERIC Educational Resources Information Center
Orsini, Larry L.; Hudack, Lawrence R.; Zekan, Donald L.
1999-01-01
The value-added statement (VAS), relatively unknown in the United States, is used in financial reports by many European companies. Saint Bonaventure University (New York) has adapted a VAS to make it appropriate for not-for-profit universities by identifying stakeholder groups (students, faculty, administrators/support personnel, creditors, the…
Educational intervention with multiply handicapped preschool children.
Kaminer, R K; Chinitz, S P
1982-02-01
A study was conducted to objectively measure changes in functioning of multiply handicapped children in a specialized nursery school program. The study population consisted of the 18 children who entered the program in the study year. A quantitative teacher rating scale was developed, tested, and found to be reliable. Significant improvements were demonstrated in interaction, communication, and task orientation after 3 months and in self-care after 6 months. There was no measurable change in motor performance, and the intellectual functioning of the children remained in the same diagnostic category as at the outset. The study documented improvement on social competence of multiply handicapped children enrolled in a preschool program with minimal parental involvement. The teacher rating scale was found to be useful in measuring social functioning in a school setting for a young population with a limited range of possible achievements. Teachers proved to be reliable evaluators of their pupils. To measure social and interactional parameters, it appears necessary to have both a standardized instrument and an informed observer who knows the child's daily functioning. PMID:6460491
NASA Astrophysics Data System (ADS)
Albacete, Javier L.; Kovchegov, Yuri V.; Taliotis, Anastasios
2009-03-01
We calculate the total cross section for the scattering of a quark-anti-quark dipole on a large nucleus at high energy for a strongly coupled N = 4 super Yang-Mills theory using AdS/CFT correspondence. We model the nucleus by a metric of a shock wave in AdS5. We then calculate the expectation value of the Wilson loop (the dipole) by finding the extrema of the Nambu-Goto action for an open string attached to the quark and antiquark lines of the loop in the background of an AdS5 shock wave. We find two physically meaningful extremal string configurations. For both solutions we obtain the forward scattering amplitude N for the quark dipole-nucleus scattering. We study the onset of unitarity with increasing center-of-mass energy and transverse size of the dipole: we observe that for both solutions the saturation scale Qs is independent of energy/Bjorken-x and depends on the atomic number of the nucleus as Qs˜A1/3. Finally we observe that while one of the solutions we found corresponds to the pomeron intercept of αP = 2 found earlier in the literature, when extended to higher energy or larger dipole sizes it violates the black disk limit. The other solution we found respects the black disk limit and yields the pomeron intercept of αP = 1.5. We thus conjecture that the right pomeron intercept in gauge theories at strong coupling may be αP = 1.5.
On multipliers of Fourier series in the Lorentz space
NASA Astrophysics Data System (ADS)
Ydyrys, Aizhan Zh.; Tleukhanova, Nazerke T.
2016-08-01
We study the multipliers of Fourier series on the Lorentz spaces, in particular, the sufficient conditions for a sequence of complex numbers {λk}k∈Z in order to make it a multiplier of trigonometric Fourier series of space Lp,r [0; 1] in the Lq,r [0; 1]. In the paper there is a new multipliers theorem which is supplement of the well-known theorems, and given a counterexample.
Multiplier Accounting of Indian Mining Industry--The Concept
NASA Astrophysics Data System (ADS)
Hussain, A.; Karmakar, N. C.
2015-04-01
Input-output multipliers are indicators used for predicting the total impact on an economy due to the changes in its industrial demand and output. Also, input-output tables provide detailed dissection of the intermediate transactions in an economy. The aim of the paper is to put forward a basic framework of input-output economics as well as the multiplier concept. The outline of the methodology for calculating the multiplier associated with Indian mining industry is also presented.
Faster Double-Size Bipartite Multiplication out of Montgomery Multipliers
NASA Astrophysics Data System (ADS)
Yoshino, Masayuki; Okeya, Katsuyuki; Vuillaume, Camille
This paper proposes novel algorithms for computing double-size modular multiplications with few modulus-dependent precomputations. Low-end devices such as smartcards are usually equipped with hardware Montgomery multipliers. However, due to progresses of mathematical attacks, security institutions such as NIST have steadily demanded longer bit-lengths for public-key cryptography, making the multipliers quickly obsolete. In an attempt to extend the lifespan of such multipliers, double-size techniques compute modular multiplications with twice the bit-length of the multipliers. Techniques are known for extending the bit-length of classical Euclidean multipliers, of Montgomery multipliers and the combination thereof, namely bipartite multipliers. However, unlike classical and bipartite multiplications, Montgomery multiplications involve modulus-dependent precomputations, which amount to a large part of an RSA encryption or signature verification. The proposed double-size technique simulates double-size multiplications based on single-size Montgomery multipliers, and yet precomputations are essentially free: in an 2048-bit RSA encryption or signature verification with public exponent e=216+1, the proposal with a 1024-bit Montgomery multiplier is at least 1.5 times faster than previous double-size Montgomery multiplications.
Four-gate transistor analog multiplier circuit
NASA Technical Reports Server (NTRS)
Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)
2011-01-01
A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.
Bilinear modeling via augmented Lagrange multipliers (BALM).
Del Bue, Alessio; Xavier, João; Agapito, Lourdes; Paladini, Marco
2012-08-01
This paper presents a unified approach to solve different bilinear factorization problems in computer vision in the presence of missing data in the measurements. The problem is formulated as a constrained optimization where one of the factors must lie on a specific manifold. To achieve this, we introduce an equivalent reformulation of the bilinear factorization problem that decouples the core bilinear aspect from the manifold specificity. We then tackle the resulting constrained optimization problem via Augmented Lagrange Multipliers. The strength and the novelty of our approach is that this framework can seamlessly handle different computer vision problems. The algorithm is such that only a projector onto the manifold constraint is needed. We present experiments and results for some popular factorization problems in computer vision such as rigid, non-rigid, and articulated Structure from Motion, photometric stereo, and 2D-3D non-rigid registration. PMID:22156102
Multiplier-continuation algorthms for constrained optimization
NASA Technical Reports Server (NTRS)
Lundberg, Bruce N.; Poore, Aubrey B.; Bing, Yang
1989-01-01
Several path following algorithms based on the combination of three smooth penalty functions, the quadratic penalty for equality constraints and the quadratic loss and log barrier for inequality constraints, their modern counterparts, augmented Lagrangian or multiplier methods, sequential quadratic programming, and predictor-corrector continuation are described. In the first phase of this methodology, one minimizes the unconstrained or linearly constrained penalty function or augmented Lagrangian. A homotopy path generated from the functions is then followed to optimality using efficient predictor-corrector continuation methods. The continuation steps are asymptotic to those taken by sequential quadratic programming which can be used in the final steps. Numerical test results show the method to be efficient, robust, and a competitive alternative to sequential quadratic programming.
[Digital subtraction radiography for the detection of periodontal bone changes].
Mera, T
1989-03-01
This study was performed to evaluate the efficacy of digital subtraction radiography in detecting alveolar bone changes. In order to test the sensitivity of quantitative evaluation by subtraction radiography, a copper equivalent thickness obtained from digitized radiographs was compared with the actual mineral content of bone phantoms with 15 different minerals and 25 bone specimens. Results demonstrated that the copper equivalent thickness correlated well with the actual mineral content (bone phantoms: gamma s = 1.0, bone specimens: gamma s = 0.985). In order to test the ability of digitized subtraction radiography in assessing alveolar bone changes in vivo, subtraction images were compared with histological features. The experimental angular bony defects were treated with conservative periodontal therapy in 3 monkeys. The standardized radiographs were taken longitudinally after therapy, and subtraction images were made from the sequentially obtained radiographs. In addition, for fluorescent histomorphometrical evaluations of new bone formations, the animals were dosed with oxytetracycline, calsein solution and arizarin complex solution. Radiographic and histological evaluations were scheduled to provide healing periods of 2, 3, 4, 5, 6 and 9 weeks after periodontal therapy. Subtraction radiography offered an objective method to follow histological changes of alveolar bone, and the copper equivalent thickness obtained from subtraction radiographs correlated with the histometric bone volume (gamma s = 0.9023, p less than 0.01). The results of these studies indicated that subtraction radiography was useful in monitoring alveolar bone changes associated with periodontal disease and treatment and that the quanitative measurement of periodontal bone changes by subtraction radiography was feasible. PMID:2517790
Observability of Multiply Reflected P Waves
NASA Astrophysics Data System (ADS)
Foundotos, Michel; Nolet, Guust
2010-05-01
In order to constrain the shallow structure of the Earth in global tomography, Love and Rayleigh waves are often used. However these waves are mostly sensitive to the S wave velocity structure. P-wave energy is either evanescent, or leaking away at every surface reflection that generates an S wave which travels much deeper into the mantle. For that reason, to study the shallow P velocity structure of the Earth, we need to study P-waves at regional distances if a good seismic station coverage is available. Otherwise we can use multiple P reflections at teleseismic distance when regional data are not available (as in the oceans for instance). The major aim of this work was first of all to ensure that these multiply reflected P waves can adequately be observed in real data and also to investigate how many reflections at the surface these reflected waves can still be seen and to investigate how strongly the amplitude of multiply reflected P diminishes because of energy loss into S waves. For this study we are comparing the synthetic predictions computed with a Spectral Element Method for a spherically symmetric earth (Nissen-Meyer et al, 2007) with observed data. Attention will be made on Synthetics with and without oceanic reflection points and compare these with observations. We used 300 events recorded (90000 seismograms) from the dense network of US ARRAY, which allows us to make a very large number of observations. Our study shows that three times reflected PPP waves are very well observed for epicentral distances > 60 degrees and for events with Mw > 5.5 , despite the ray-theoretical prediction that at certain distances almost all of their compressional energy is converted to shear waves. However, the four times reflected PPPP waves do not appear everywhere clearly. PPPP can be observed for epicentral distances > 90 degrees.
Nucleon-nucleon scattering within a multiple subtractive renormalization approach
Timoteo, V. S.; Frederico, T.; Delfino, A.; Tomio, Lauro
2011-06-15
We present a methodology to renormalize the nucleon-nucleon interaction in momentum space, using a recursive multiple subtraction approach that prescinds from a cutoff regularization, to construct the kernel of the scattering equation. The subtracted scattering equation is solved with the next-leading-order and next-to-next-leading-order interactions. The results are presented for all partial waves up to j=2, fitted to low-energy experimental data. In this renormalization group invariant approach, the subtraction energy emerges as a renormalization scale and the momentum associated with it comes to be about the QCD scale ({Lambda}{sub QCD}), irrespectively to the partial wave.
Dual-tracer background subtraction approach for fluorescent molecular tomography
Holt, Robert W.; El-Ghussein, Fadi; Davis, Scott C.; Samkoe, Kimberley S.; Gunn, Jason R.; Leblond, Frederic
2013-01-01
Abstract. Diffuse fluorescence tomography requires high contrast-to-background ratios to accurately reconstruct inclusions of interest. This is a problem when imaging the uptake of fluorescently labeled molecularly targeted tracers in tissue, which can result in high levels of heterogeneously distributed background uptake. We present a dual-tracer background subtraction approach, wherein signal from the uptake of an untargeted tracer is subtracted from targeted tracer signal prior to image reconstruction, resulting in maps of targeted tracer binding. The approach is demonstrated in simulations, a phantom study, and in a mouse glioma imaging study, demonstrating substantial improvement over conventional and homogenous background subtraction image reconstruction approaches. PMID:23292612
Towards Special Daemon-Sensitive Electron Multiplier:. Positive Outcome of March 2009 Experiment
NASA Astrophysics Data System (ADS)
Drobyshevski, E. M.; Drobyshevski, M. E.
Results of the experiments on daemon detection performed in St-Petersburg in March 2009 are presented. Adding the data obtained with the daemon-sensitive FEU-167-1 PM tubes to the data amassed in our previous measurements (starting from 2000) raises the confidence level of existence of the spring maximum in NEACHO (near-Earth almost circular heliocentric orbit) daemon flux to ~ 5σ. The first test experiments conducted with the "dark" electron multiplier tubes, TEU-167 with a thick (~ 0.5 μm) Al coating over all of the inner surface of the near-cathode multiplier section, including also its front screen, look encouraging. They provide supportive evidence for the existence of diurnal modulation of the daemon flux and offer ~ 3.4 × 10-7 cm-2s-1 for its lower limit in March, in good agreement with our earlier estimates and measurements.
Albacete, Javier L.; Kovchegov, Yuri V.; Taliotis, Anastasios
2009-03-23
We calculate the total cross section for the scattering of a quark-anti-quark dipole on a large nucleus at high energy for a strongly coupled N = 4 super Yang-Mills theory using AdS/CFT correspondence. We model the nucleus by a metric of a shock wave in AdS{sub 5}. We then calculate the expectation value of the Wilson loop (the dipole) by finding the extrema of the Nambu-Goto action for an open string attached to the quark and antiquark lines of the loop in the background of an AdS{sub 5} shock wave. We find two physically meaningful extremal string configurations. For both solutions we obtain the forward scattering amplitude N for the quark dipole-nucleus scattering. We study the onset of unitarity with increasing center-of-mass energy and transverse size of the dipole: we observe that for both solutions the saturation scale Q{sub s} is independent of energy/Bjorken-x and depends on the atomic number of the nucleus as Q{sub s}{approx}A{sup 1/3}. Finally we observe that while one of the solutions we found corresponds to the pomeron intercept of {alpha}{sub P} = 2 found earlier in the literature, when extended to higher energy or larger dipole sizes it violates the black disk limit. The other solution we found respects the black disk limit and yields the pomeron intercept of {alpha}{sub P} = 1.5. We thus conjecture that the right pomeron intercept in gauge theories at strong coupling may be {alpha}{sub P} = 1.5.
ERIC Educational Resources Information Center
Cerron-Palomino Lopez, Alvaro
2010-01-01
This dissertation is a variationist account of two non-standard relative clause (RC) structures in Spanish: resumptive pronouns (RPs) and prepositional-phrase (PP) chopping. Previous typological studies considered RP explanations based on difficulty of processing (Hawkins, 1994), while Spanish-specific quantitative studies proposed a number of…
Background Subtraction for Automated Multisensor Surveillance: A Comprehensive Review
NASA Astrophysics Data System (ADS)
Cristani, Marco; Farenzena, Michela; Bloisi, Domenico; Murino, Vittorio
2010-12-01
Background subtraction is a widely used operation in the video surveillance, aimed at separating the expected scene (the background) from the unexpected entities (the foreground). There are several problems related to this task, mainly due to the blurred boundaries between background and foreground definitions. Therefore, background subtraction is an open issue worth to be addressed under different points of view. In this paper, we propose a comprehensive review of the background subtraction methods, that considers also channels other than the sole visible optical one (such as the audio and the infrared channels). In addition to the definition of novel kinds of background, the perspectives that these approaches open up are very appealing: in particular, the multisensor direction seems to be well-suited to solve or simplify several hoary background subtraction problems. All the reviewed methods are organized in a novel taxonomy that encapsulates all the brand-new approaches in a seamless way.
An auto-adaptive background subtraction method for Raman spectra.
Xie, Yi; Yang, Lidong; Sun, Xilong; Wu, Dewen; Chen, Qizhen; Zeng, Yongming; Liu, Guokun
2016-05-15
Background subtraction is a crucial step in the preprocessing of Raman spectrum. Usually, parameter manipulating of the background subtraction method is necessary for the efficient removal of the background, which makes the quality of the spectrum empirically dependent. In order to avoid artificial bias, we proposed an auto-adaptive background subtraction method without parameter adjustment. The main procedure is: (1) select the local minima of spectrum while preserving major peaks, (2) apply an interpolation scheme to estimate background, (3) and design an iteration scheme to improve the adaptability of background subtraction. Both simulated data and Raman spectra have been used to evaluate the proposed method. By comparing the backgrounds obtained from three widely applied methods: the polynomial, the Baek's and the airPLS, the auto-adaptive method meets the demand of practical applications in terms of efficiency and accuracy. PMID:26950502
Soft-collinear factorization and zero-bin subtractions
Chiu Juiyu; Fuhrer, Andreas; Kelley, Randall; Manohar, Aneesh V.; Hoang, Andre H.
2009-03-01
We study the Sudakov form factor for a spontaneously broken gauge theory using a (new) {delta}-regulator. To be well defined, the effective theory requires zero-bin subtractions for the collinear sectors. The zero-bin subtractions depend on the gauge boson mass M and are not scaleless. They have both finite and 1/{epsilon} contributions and are needed to give the correct anomalous dimension and low-scale matching contributions. We also demonstrate the necessity of zero-bin subtractions for soft-collinear factorization. We find that after zero-bin subtractions the form factor is the sum of the collinear contributions minus a soft mass-mode contribution, in agreement with a previous result of Idilbi and Mehen in QCD. This appears to conflict with the method-of-regions approach, where one gets the sum of contributions from different regions.
An auto-adaptive background subtraction method for Raman spectra
NASA Astrophysics Data System (ADS)
Xie, Yi; Yang, Lidong; Sun, Xilong; Wu, Dewen; Chen, Qizhen; Zeng, Yongming; Liu, Guokun
2016-05-01
Background subtraction is a crucial step in the preprocessing of Raman spectrum. Usually, parameter manipulating of the background subtraction method is necessary for the efficient removal of the background, which makes the quality of the spectrum empirically dependent. In order to avoid artificial bias, we proposed an auto-adaptive background subtraction method without parameter adjustment. The main procedure is: (1) select the local minima of spectrum while preserving major peaks, (2) apply an interpolation scheme to estimate background, (3) and design an iteration scheme to improve the adaptability of background subtraction. Both simulated data and Raman spectra have been used to evaluate the proposed method. By comparing the backgrounds obtained from three widely applied methods: the polynomial, the Baek's and the airPLS, the auto-adaptive method meets the demand of practical applications in terms of efficiency and accuracy.
Improvements in floating point addition/subtraction operations
Farmwald, P.M.
1984-02-24
Apparatus is described for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.
Circuit multiplies pulse width modulation, exhibits linear transfer function
NASA Technical Reports Server (NTRS)
Carlson, A. W.; Furciniti, A.
1967-01-01
Modulation multiplier provides a simple means of multiplying the width modulation of a pulse train by a constant factor. It operates directly on a pulse width modulated input signal to generate an output pulse train having a greater degree of width modulation than the input signal.
Improved Algorithm For Finite-Field Normal-Basis Multipliers
NASA Technical Reports Server (NTRS)
Wang, C. C.
1989-01-01
Improved algorithm reduces complexity of calculations that must precede design of Massey-Omura finite-field normal-basis multipliers, used in error-correcting-code equipment and cryptographic devices. Algorithm represents an extension of development reported in "Algorithm To Design Finite-Field Normal-Basis Multipliers" (NPO-17109), NASA Tech Briefs, Vol. 12, No. 5, page 82.
NASA Astrophysics Data System (ADS)
Martelli, Dario; Morales, Jose F.
2005-02-01
In the light of the recent Lin, Lunin, Maldacena (LLM) results, we investigate 1/2-BPS geometries in minimal (and next to minimal) supergravity in D = 6 dimensions. In the case of minimal supergravity, solutions are given by fibrations of a two-torus T2 specified by two harmonic functions. For a rectangular torus the two functions are related by a non-linear equation with rare solutions: AdS3 × S3, the pp-wave and the multi-center string. ``Bubbling'', i.e. superpositions of droplets, is accommodated by allowing the complex structure of the T2 to vary over the base. The analysis is repeated in the presence of a tensor multiplet and similar conclusions are reached, with generic solutions describing D1D5 (or their dual fundamental string-momentum) systems. In this framework, the profile of the dual fundamental string-momentum system is identified with the boundaries of the droplets in a two-dimensional plane.
Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing
NASA Technical Reports Server (NTRS)
Bahr, Christopher J.; Horne, William C.
2015-01-01
An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.
Grant, E.J.; Macey, D.J.; Bayouth, J.E.
1994-05-01
Dose estimates for organs and tumor volumes in radioimmunotherapy with I-131 frequently depend on in-vivo quantitation methods using planar Anger camera images. Compton scatter and collimator septal penetration result in overestimation of activity and dose. The objective of this study was to assess the effectiveness of a triple energy window subtraction method for quantitative imaging of I-131. The energy spectrum of I-131 was modeled as a superposition of the spectra of Cr-51 (320 keV) and Cs-137 (662 keV). Images were acquired with three adjacent 15% energy windows--photopeak(PP), upper scatter(US), and lower scatter(LS)--for small sources of these radionuclides. The PP window was centered at 364 keV for I-131 and Cs-137 and 320 keV for Cr-51. Three scatter multipliers were derived from analysis of count profiles of the Cs-137 and Cr-51 images, and used to sequentially remove septal penetration and scatter events included in the 364 keV photopeak of I-131. This method was tested by acquiring images of an abdominal phantom containing a liver, spleen and spherical {open_quotes}tumor{close_quotes} filled with different concentrations of I-131, both with and without background activity in the surrounding phantom. A body thickness attenuation compensation factor was applied to the geometric mean of the conjugate view counts using a narrow beam linear attenuation coefficient of 0.11 cm{sup -1}. With scatter subtraction, the accuracy and reproducibility of activity quantitation was improved because the background count density was more uniformly scored. Also, the influence of different activity concentrations in source organs relative to background on the accuracy of quantitation was removed, and the perimeters of organs were more clearly defined. This method has been used to provide improved dose estimates for I-131 labeled antibody therapy in breast cancer patients.
Comparison of iodine K-edge subtraction and fluorescence subtraction imaging in an animal system
NASA Astrophysics Data System (ADS)
Zhang, H.; Zhu, Y.; Bewer, B.; Zhang, L.; Korbas, M.; Pickering, I. J.; George, G. N.; Gupta, M.; Chapman, D.
2008-09-01
K-Edge Subtraction (KES) utilizes the discontinuity in the X-ray absorption across the absorption edge of the selected contrast element and creates an image of the projected density of the contrast element from two images acquired just above and below the K-edge of the contrast element. KES has proved to be powerful in coronary angiography, micro-angiography, bronchography, and lymphatic imaging. X-ray fluorescence imaging is a successful technique for the detection of dilute quantities of elements in specimens. However, its application at high X-ray energies (e.g. at the iodine K-edge) is complicated by significant Compton background, which may enter the energy window set for the contrast material's fluorescent X-rays. Inspired by KES, Fluorescence Subtraction Imaging (FSI) is a technique for high-energy (>20 keV) fluorescence imaging using two different incident beam energies just above and below the absorption edge of a contrast element (e.g. iodine). The below-edge image can be assumed as a "background" image, which includes Compton scatter and fluorescence from other elements. The above-edge image will contain nearly identical spectral content as the below-edge image but will contain the additional fluorescence of the contrast element. This imaging method is especially promising with thick objects with dilute contrast materials, significant Compton background, and/or competing fluorescence lines from other materials. A quality factor is developed to facilitate the comparison. The theoretical value of the quality factor sets the upper limit that an imaging method can achieve when the noise is Poisson limited. The measured value of this factor makes two or more imaging methods comparable. Using the Hard X-ray Micro-Analysis (HXMA) beamline at the Canadian Light Source (CLS), the techniques of FSI and KES were critically compared, with reference to radiation dose, image acquisition time, resolution, signal-to-noise ratios, and quality factor.
Synthesis and characterization of multiply-tyrosinated, multiply-iodinated somatostatin analogs
Woltering, E A.; O'Dorisio, M S.; Murphy, W A.; Chen, F; Drouant, G J.; Espenan, G D.; Fisher, Darrell R.; Sharma, C; Diaco, D S.; Maloney, T M.; Fuselier, J A.; Nelson, J A.; O'Dorisio, T M.; Coy, D H.
1999-02-01
Radio-labeled somatostatin analogs have recently gained popularity as agents useful in intraoperative tumor localization, external scintigraphy and in situ radiotherapy. We have synthesized and characterized a series of novel N-terminally extended multiply-tyrosinated somatostatin analogs that possess high binding affinity for somatostatin receptors, exhibit biological activity comparable to the native peptide and retain these characteristics after iodination. These analogs can be radio-iodinated to high specific activities. Following radio-iodination, these analogs exhibit minimal radiolysis and may be clinically useful for tumor localization, scanning and therapy.
Yeh, Y. S.; Cheng, J. H.; Chen, L. K.; Hung, C. W.; Lo, C. Y.; Liao, C. W.
2008-02-15
Harmonic multiplying gyrotron traveling-wave amplifiers (gyro-TWTs) provide magnetic field reduction and frequency multiplication. However, spurious oscillations may reduce the amplification of the gyro-TWT. Most distributed-loss structures are stabilized in gyro-TWTs that operate at low beam currents. Attenuating severs are added to the interaction circuit of a distributed-loss gyro-TWT to prevent high beam currents that result in mode competition. This study proposes a Ka-band harmonic multiplying gyro-TWT, using distributed wall losses and attenuating severs, to improve the stability of the amplification and the performance of the amplifier. Simulation results reveal that the absolute instabilities are effectively suppressed by wall losses of the lossy and severed sections, especially in the low-k{sub z} and high-order modes. Meanwhile, the severed section, dividing an interaction circuit into several short sections, reduces the effective interaction lengths of the absolute instabilities. The stable harmonic multiplying gyro-TWT is predicted to yield a peak output power of 230 kW at 33.65 GHz with an efficiency of 30%, a saturated gain of 40 dB, and a 3 dB bandwidth of 0.8 GHz for a 60 kV, 13 A electron beam with an axial velocity spread of {delta}v{sub z}/v{sub z}=8%. The power/gain scaling and phase relation between the drive and the output waves are elucidated.
Gas Electron Multiplier (GEM) Chamber Characteristics Test
Yu, Jaehoon; White, Andy; Park, Seongtae; Hahn, Changhie; Baldeloma, Edwin; Tran, Nam; McIntire, Austin; Soha, Aria; /Fermilab
2011-01-11
Gas Electron Multipliers (GEMs) have been used in many HEP experiments as tracking detectors. They are sensitive to X-rays which allows use beyond that of HEP. The UTA High Energy group has been working on using GEMs as the sensitive gap detector in a DHCAL for the ILC. The physics goals at the ILC put a stringent requirement on detector performance. Especially the precision required for jet mass and positions demands an unprecedented jet energy resolution to hadronic calorimeters. A solution to meet this requirement is using the Particle Flow Algorithm (PFA). In order for PFA to work well, high calorimeter granularity is necessary. Previous studies based on GEANT simulations using GEM DHCAL gave confidence on the performance of GEM in the sensitive gap in a sampling calorimeter and its use as a DHCAL in PFA. The UTA HEP team has built several GEM prototype chambers, including the current 30cm x 30cm chamber integrated with the SLAC-developed 64 channel kPiX analog readout chip. This chamber has been tested on the bench using radioactive sources and cosmic ray muons. In order to have fuller understanding of various chamber characteristics, the experiments plan to expose 1-3 GEM chambers of dimension 35cm x 35cm x 5cm with 1cm x 1cm pad granularity with 64 channel 2-D simultaneous readout using the kPiX chip. In this experiment the experiments pan to measure MiP signal height, chamber absolute efficiencies, chamber gain versus high voltage across the GEM gap, the uniformity of the chamber across the 8cm x 8cm area, cross talk and its distance dependence to the triggered pad, chamber rate capabilities, and the maximum pad occupancy rate.
Improved Program For Calculation Of Heat-Load Multiplier
NASA Technical Reports Server (NTRS)
D'Valentine, Mark
1995-01-01
PRM1940 computer program computes heat-load multiplier for use in Power Balance Model (PBM) computer program which calculates hundreds of operating parameters of main engine of space shuttle from relatively few measurement data. PRM1940 is stand-alone program which incorporates only those PBM calculations necessary to compute heat-load multiplier. Developed to accelerate and partly automate calculation of heat-load multiplier. Although programs specific to space shuttle application, also of interest to engineers concerned with monitoring of conditions in turbines, chemical-processing plants, and other high-temperature flow machinery.
Appearance of the canine meninges in subtraction magnetic resonance images.
Lamb, Christopher R; Lam, Richard; Keenihan, Erin K; Frean, Stephen
2014-01-01
The canine meninges are not visible as discrete structures in noncontrast magnetic resonance (MR) images, and are incompletely visualized in T1-weighted, postgadolinium images, reportedly appearing as short, thin curvilinear segments with minimal enhancement. Subtraction imaging facilitates detection of enhancement of tissues, hence may increase the conspicuity of meninges. The aim of the present study was to describe qualitatively the appearance of canine meninges in subtraction MR images obtained using a dynamic technique. Images were reviewed of 10 consecutive dogs that had dynamic pre- and postgadolinium T1W imaging of the brain that was interpreted as normal, and had normal cerebrospinal fluid. Image-anatomic correlation was facilitated by dissection and histologic examination of two canine cadavers. Meningeal enhancement was relatively inconspicuous in postgadolinium T1-weighted images, but was clearly visible in subtraction images of all dogs. Enhancement was visible as faint, small-rounded foci compatible with vessels seen end on within the sulci, a series of larger rounded foci compatible with vessels of variable caliber on the dorsal aspect of the cerebral cortex, and a continuous thin zone of moderate enhancement around the brain. Superimposition of color-encoded subtraction images on pregadolinium T1- and T2-weighted images facilitated localization of the origin of enhancement, which appeared to be predominantly dural, with relatively few leptomeningeal structures visible. Dynamic subtraction MR imaging should be considered for inclusion in clinical brain MR protocols because of the possibility that its use may increase sensitivity for lesions affecting the meninges. PMID:24833219
Magnification Embossed Radiography Utilizing Image-Shifting Subtraction Program
NASA Astrophysics Data System (ADS)
Akihiro Osawa,; Manabu Watanabe,; Eiichi Sato,; Hiroshi Matsukiyo,; Toshiyuki Enomoto,; Jiro Nagao,; Purkhet Abderyim,; Katsuo Aizawa,; Etsuro Tanaka,; Hidezo Mori,; Toshiaki Kawai,; Akira Ogawa,; Kiyomi Takahashi,; Shigehiro Sato,; Jun Onagawa,
2010-03-01
We developed an image-shifting subtraction program and carried out magnification embossed radiography (MER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of the target region was increased by the use of subtraction software and a linear-contrast system in a flat-panel detector (FPD). The X-ray generator had a 100-μm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. MER images with threefold magnification were obtained using the FPD with a pixel size of 48× 48 μm2, and the shifting dimensions of the imaged object in the horizontal and vertical directions ranged from 48 to 192 μm. At a shifting distance ranging from 48 to 144 μm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 50 μm. In the MER of nonliving animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, and iodine-based microspheres in coronary arteries of approximately 100 μm diameter.
Embossed radiography utilizing an image-shifting subtraction program
NASA Astrophysics Data System (ADS)
Sato, Eiichi; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Takahashi, Kiyomi; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun
2010-07-01
We developed an image-shifting subtraction program and carried out embossed radiography (ER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of a target region was increased using the subtraction program and a linear-contrast system in a flat panel detector (FPD). The X-ray generator had a 100 μm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. ER was achieved with cohesion imaging using the FPD with pixel sizes of 48×48 μm 2, and the shifting dimension of an object in the horizontal and vertical directions ranged from 48 to 96 μm. At a shifting distance of 96 μm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 83 μm. In ER of animal phantoms, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, iodine-based microspheres in coronary arteries approximately 100 μm in diameter.
Magnification Embossed Radiography Utilizing Image-Shifting Subtraction Program
NASA Astrophysics Data System (ADS)
Osawa, Akihiro; Watanabe, Manabu; Sato, Eiichi; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Nagao, Jiro; Abderyim, Purkhet; Aizawa, Katsuo; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Ogawa, Akira; Takahashi, Kiyomi; Sato, Shigehiro; Onagawa, Jun
2010-03-01
We developed an image-shifting subtraction program and carried out magnification embossed radiography (MER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of the target region was increased by the use of subtraction software and a linear-contrast system in a flat-panel detector (FPD). The X-ray generator had a 100-µm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. MER images with threefold magnification were obtained using the FPD with a pixel size of 48×48 µm2, and the shifting dimensions of the imaged object in the horizontal and vertical directions ranged from 48 to 192 µm. At a shifting distance ranging from 48 to 144 µm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 50 µm. In the MER of nonliving animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, and iodine-based microspheres in coronary arteries of approximately 100 µm diameter.
Systolic multiplier for finite fields gf(2/sup m/)
Yeh, C.S.; Reed, I.S.
1983-01-01
A systolic architecture is developed for performing the product-sum computation, ab+c, in the finite field gf(2/sup m/) of 2/sup m/ elements, where a, b and c are arbitrary elements of gf(2/sup m/). The multiplier is a serial-in, serial-out, one-dimensional systolic array. This multiplier for gf(2/sup m/) requires m basic cells. The average time per computation of the multiplier is m time units if a number of computations are computed consecutively. To perform an isolated computation the multiplier requires 3m time units. The architecture is simple and regular and possesses the desirable properties of concurrency and modularity and is well suited for use. 10 references.
Operational Safety Requirements Neutron Multiplier Facility in 329 Building
EA. Lepel
1992-10-01
The operational safety requirements (OSRs) presented in this report define the conditions, safe boundaries and management control needed for safely operating the Neutron Multiplier Facility in the 329 Building Annex.
Montgomery Multiplication with Twice the Bit-Length of Multipliers
NASA Astrophysics Data System (ADS)
Yoshino, Masayuki; Okeya, Katsuyuki; Vuillaume, Camille
We present a novel approach for computing 2n-bit Montgomery multiplications with n-bit hardware Montgomery multipliers. Smartcards are usually equipped with such hardware Montgomery multipliers; however, due to progresses in factoring algorithms, the recommended bit length of public-key schemes such as RSA is steadily increasing, making the hardware quickly obsolete. Thanks to our double-size technique, one can re-use the existing hardware while keeping pace with the latest security requirements. Unlike the other double-size techniques which rely on classical n-bit modular multipliers, our idea is tailored to take advantage of n-bit Montgomery multipliers. Thus, our technique increases the perenniality of existing products without compromises in terms of security.
Multiplier less high-speed squaring circuit for binary numbers
NASA Astrophysics Data System (ADS)
Sethi, Kabiraj; Panda, Rutuparna
2015-03-01
The squaring operation is important in many applications in signal processing, cryptography etc. In general, squaring circuits reported in the literature use fast multipliers. A novel idea of a squaring circuit without using multipliers is proposed in this paper. Ancient Indian method used for squaring decimal numbers is extended here for binary numbers. The key to our success is that no multiplier is used. Instead, one squaring circuit is used. The hardware architecture of the proposed squaring circuit is presented. The design is coded in VHDL and synthesised and simulated in Xilinx ISE Design Suite 10.1 (Xilinx Inc., San Jose, CA, USA). It is implemented in Xilinx Vertex 4vls15sf363-12 device (Xilinx Inc.). The results in terms of time delay and area is compared with both modified Booth's algorithm and squaring circuit using Vedic multipliers. Our proposed squaring circuit seems to have better performance in terms of both speed and area.
Sociophysics of sexism: normal and anomalous petrie multipliers
NASA Astrophysics Data System (ADS)
Eliazar, Iddo
2015-07-01
A recent mathematical model by Karen Petrie explains how sexism towards women can arise in organizations where male and female are equally sexist. Indeed, the Petrie model predicts that such sexism will emerge whenever there is a male majority, and quantifies this majority bias by the ‘Petrie multiplier’: the square of the male/female ratio. In this paper—emulating the shift from ‘normal’ to ‘anomalous’ diffusion—we generalize the Petrie model to a stochastic Poisson model that accommodates heterogeneously sexist men and woman, and that extends the ‘normal’ quadratic Petrie multiplier to ‘anomalous’ non-quadratic multipliers. The Petrie multipliers span a full spectrum of behaviors which we classify into four universal types. A variation of the stochastic Poisson model and its Petrie multipliers is further applied to the context of cyber warfare.
Sky background subtraction with fiber-fed spectrographs
NASA Astrophysics Data System (ADS)
Puech, M.; Rodrigues, M.; Yang, Y.; Flores, H.; Royer, F.; Disseau, K.; Gonçalves, T.; Hammer, F.; Cirasuolo, M.; Evans, C. J.; Li Causi, G.; Maiolino, R.; Melo, C.
2014-08-01
Fiber-fed spectrographs can now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached on such instruments has often been pinpointed as one of their major issues, in relation to difficulties in scattered light and flat-field corrections or throughput losses associated with fibers. Using technical time observations with FLAMES-GIRAFFE, two observing techniques, namely dual staring and cross beam switching modes, were tested and the resulting sky subtraction accuracy reached in both cases was quantified. Results indicate that an accuracy of 0.6% on the sky subtraction can be reached, provided that the cross beam switching mode is used. This is very encouraging regarding the detection of very faint sources with future fiber-fed spectrographs such as VLT/MOONS or E-ELT/MOSAIC.
Digital subtraction angiography of the portal venous system
Foley, W.D.; Stewart E.T.; Milbrath, J.R.; SanDretto, M.; Milde, M.
1983-03-01
Venous-phase arteriography after celiac or superior mesenteric artery injection is the most common technique used to demonstrate portal venous anatomy, flow direction, and portal systemic shunts. Large-volume contrast material injections and intraarterial vasodilators or balloon occlusion technique are required for optimal examinations using film-screen recording. A technique for performing venous-phase arteriography with digital subtraction imaging after celiac and superior mesenteric artery injection is described. The major advantage of intraarterial digital subtraction technique in comparison to film-screen recording is sensitivity to intravascular iodine with a consequent reduction in contrast material load and examination time. Technical success is limited only by motion artifact and should approximate the 80%-90% figure achieved for intravenous digital subtraction angiography of the aortorenal vessels.
Proposed smart integrated-optical preprocessor using holographic subtraction
NASA Technical Reports Server (NTRS)
Verber, C. M.; Vahey, D. W.
1979-01-01
The paper presents a proposed integrated-optical preprocessor with a holographic subtraction. It is based on an optical analog of a set of N analog voltages formed by passing an optical plane wave, confined in an electrooptic waveguide, under a set of N electrodes to which the voltages are applied; in the limit in which diffraction is ignored, the wavefront of the emerging guided wave will have superimposed upon it N discrete phase shifts. Processors which operate upon voltages encoded in this manner are being fabricated; they include a comparator in which incoming data are compared to a holographic record of the optical analog of a reference set, and a 'smart' system based upon holographic self-subtraction, in which the processor can independently adapt to changes in background information. The preprocessor operation is described in the screening, identification, and the self-subtraction modes, and implementation of devices in an integrated optical configuration is discussed.
Quantum-well diode frequency multipliers - Varistor case
NASA Technical Reports Server (NTRS)
Batelaan, Paul D.; Tolmunen, Timo J.; Frerking, Margaret A.
1992-01-01
Local oscillators for heterodyne receivers at submillimeter wavelengths are typically made using a fundamental source followed by a harmonic frequency multiplier. An investigation of the required circuit embedding conditions for a possible new harmonic generator, the quantum-well resonant-tunneling diode, is summarized. A low-frequency multiplier has been tested that employs the resistive nonlinearity of the device as opposed to the reactive nonlinearity. The results show good agreement between practice and theory.
A VLSI single chip 8-bit finite field multiplier
NASA Technical Reports Server (NTRS)
Deutsch, L. J.; Shao, H. M.; Hsu, I. S.; Truong, T. K.
1985-01-01
A Very Large Scale Integration (VLSI) architecture and layout for an 8-bit finite field multiplier is described. The algorithm used in this design was developed by Massey and Omura. A normal basis representation of finite field elements is used to reduce the multiplication complexity. It is shown that a drastic improvement was achieved in this design. This multiplier will be used intensively in the implementation of an 8-bit Reed-Solomon decoder and in many other related projects.
Animal experiments by K-edge subtraction angiography by using SR (abstract)
NASA Astrophysics Data System (ADS)
Anno, I.; Akisada, M.; Takeda, T.; Sugishita, Y.; Kakihana, M.; Ohtsuka, S.; Nishimura, K.; Hasegawa, S.; Takenaka, E.; Hyodo, K.; Ando, M.
1989-07-01
controlled by a mechanical ventilator. The respirations were held for several seconds when taking the images. Approximately 10 to 15 ml of 76% water soluble iodinated contrast medium (Urografin 76, Schering) was injected by an automatic electronic injector at the rate of approximately 10 ml/s. Three or four times injections were done so as not to exceed the normal renal excretion threshold. Intravenous drip infusion of saline (500 ml/2 h) was used to accelerate the washout of contrast medium via renal system. One hundred micrograms of nitroglycerin were administered, intravenously to dilate the coronary arteries, approximately 3 min prior to contrast injection. Sometimes we used 0.1 mg/kg of beta blockage agent (Propranorol) to decrease the heart rate. Subsequently, the heart rate of the dogs was decreased from approximately 200/s to 100/s. These techniques are commonly used in human examinations. Materials are positioned at left anterior oblique view. The sequential images are now detected above the iodine K edge by an image intensifier (RTP 9240F, Toshiba) and recorded at high signal-to-noise ratio analog video recording system (C1900, Hamamatsu Photonics, S/N 45 dB). Proximal coronary arteries are well visualized, however the distal portions are unsatisfactory, because of the overlapping of the contrast-filled dense heart chambers and pulmonary vessels. Bolus injection of contrast medium is also necessary, unless overlapping is inevitable, so are the same in conventional intravenous DSA. The energy above and below the K edge is now changed by tilting the angle of crystal, mechanically, so it has not sufficient speed to subtract the moving material. Real time A/D converter and frame buffering memories have not been available, until now. Even though there are many limitations in the hardware and many problems to overcome, our preliminary animal experiments allow us to have high expectations.
Input-output multiplier distributions from probabilistic production paths
Konecny, R.T.
1987-01-01
In the standard Leontief input-output model, a single dominant technology is assumed in the production of a particular commodity. However, in the real world, quite similar commodities are produced by firms with vastly different technologies. In addressing this limitation, the Probabilistic Production Path model (PPP) is used to investigate both the method of production and identity of the producer. An important feature of the PPP model is the consideration of the effects that heterogeneous technologies and dissimilar trade patterns have on the properties of the distribution of input-output multipliers. The derivation of the distribution of output multipliers is generalized for discrete probabilities based on market shares. Due to the complexity of the generalized solution, a simulation model is used to approximate the multiplier distribution. Results of the model show that the distributional properties of the multipliers are unpredictable, with the majority of the distributions being multimodal. Typically, the mean of the multipliers lies in a trough between two modes. Multimodal multiplier distributions were found to have a tighter symmetric interval than the corresponding standard normal confidence interval. Therefore, the use of the normal confidence interval appears to be sufficient, though overstated, for the construction of confidence intervals in the PPP model.
High speed multiplier using Nikhilam Sutra algorithm of Vedic mathematics
NASA Astrophysics Data System (ADS)
Pradhan, Manoranjan; Panda, Rutuparna
2014-03-01
This article presents the design of a new high-speed multiplier architecture using Nikhilam Sutra of Vedic mathematics. The proposed multiplier architecture finds out the compliment of the large operand from its nearest base to perform the multiplication. The multiplication of two large operands is reduced to the multiplication of their compliments and addition. It is more efficient when the magnitudes of both operands are more than half of their maximum values. The carry save adder in the multiplier architecture increases the speed of addition of partial products. The multiplier circuit is synthesised and simulated using Xilinx ISE 10.1 software and implemented on Spartan 2 FPGA device XC2S30-5pq208. The output parameters such as propagation delay and device utilisation are calculated from synthesis results. The performance evaluation results in terms of speed and device utilisation are compared with earlier multiplier architecture. The proposed design has speed improvements compared to multiplier architecture presented in the literature.
Isolation of ultrasonic scattering by wavefield baseline subtraction
NASA Astrophysics Data System (ADS)
Dawson, Alexander J.; Michaels, Jennifer E.; Michaels, Thomas E.
2016-03-01
Wavefield imaging generally refers to the measurement of signals over a two-dimensional rectilinear grid that originate from a spatially fixed source. Subtraction of such wavefields is investigated as a means of separating scattered signals from the total wavefield; that is, baseline wavefield data acquired from a defect-free specimen are subtracted from analogous data acquired after introduction of a defect. The wavefields considered here are generated by a 5 MHz angle-beam probe and measured over an area of the accessible specimen surface using a laser vibrometer. The primary challenge in isolating the scattered waves is imperfect temporal and spatial alignment of the two wavefields. Two methods for aligning the wavefields in space and time prior to performing baseline subtraction are presented and their efficacy is evaluated using data acquired before and after introducing notches that originate from a through-hole. Although perfect baseline subtraction is not achieved, the improvement in performance after alignment using either method allows for scattered waves from small defects to be separated and visualized, even when their amplitudes are much smaller than those of the incident waves.
Genomic subtraction for cloning DNA corresponding to deletion mutations.
Straus, D; Ausubel, F M
1990-01-01
We have developed a technique, called genomic subtraction, for isolating the DNA that is absent in deletion mutants. The method removes from wild-type DNA the sequences that are present in both the wild-type and the deletion mutant genomes. The DNA that corresponds to the deleted region remains. Enrichment for the deleted sequences is achieved by allowing a mixture of denatured wild-type and biotinylated mutant DNA to reassociate. After reassociation, the biotinylated sequences are removed by binding to avidin-coated beads. This subtraction process is then repeated several times. In each cycle we hybridize the unbound wild-type DNA from the previous round with fresh biotinylated deletion mutant DNA. The unbound DNA from the final cycle is ligated to adaptors and amplified by using one strand of the adaptor as a primer in the polymerase chain reaction. The amplified sequences can then be used to probe a genomic library. We applied genomic subtraction to a yeast strain that has a 5-kilobase deletion, corresponding to 1/4000th of the genome. In the experiment reported here, three rounds of subtraction were sufficient to accurately identify genomic clones containing sequences that are missing in the deletion mutant. We discuss the limitations and some potential applications of the method. Images PMID:2408039
On The Equivalence of Soft and Zero-Bin Subtractions
Thomas Mehen; Ahmad Idilbi
2007-06-01
Zero-bin subtractions are required to avoid double counting soft contributions in collinear loop integrals in Soft-Collinear Effective Theory (SCET). In traditional approaches to factorization, double counting is avoided by dividing jet functions by matrix elements of soft Wilson lines. In this paper, we compare the two approaches to double counting, studying the quark form factor and deep inelastic scattering (DIS) as x{sub B} to 1 as examples. We explain how the zero-bin subtractions in SCET are required to reproduce the well-established factorization theorem for DIS as x{sub B} to 1. We study one-loop virtual contributions to the quark form factor and real gluon emission diagrams in DIS. The two approaches to double counting are equivalent if dimensional regularization (DR) is used to regulate infrared (IR) divergences. We discuss in detail ambiguities in the calculation of one-loop scaleless integrals in DR in SCET and perturbative QCD. We also demonstrate a nontrivial check of the equivalence of the zero-bin subtraction and the soft Wilson line subtraction in the virtual two-loop Abelian contributions to the quark form factor.
"Abuelita" Epistemologies: Counteracting Subtractive Schools in American Education
ERIC Educational Resources Information Center
Gonzales, Sandra M.
2015-01-01
This autoethnographic inquiry examines the intersection of elder epistemology and subtractive education, exploring how one "abuelita" countered her granddaughter's divestment of Mexican-ness. I demonstrate how the grandmother used "abuelita" epistemologies to navigate this tension and resist the assimilative pressures felt…
Teaching Addition and Subtraction Facts: A Chinese Perspective.
ERIC Educational Resources Information Center
Sun, Wei; Zhang, Joanne Y.
2001-01-01
Presents an issue that arises in every country: How can teachers best help children master basic addition and subtraction facts? Discusses how this is handled in China and highlights the impact that language has on how children think about numbers. (KHR)
Identifying and Remediating the Subtraction Errors of Learning Disabled Adolescents.
ERIC Educational Resources Information Center
Skrtic, Thomas M.; And Others
1983-01-01
An example is provided of remediation activities for learning disabled adolescents having a specific computation difficulty with place value and the subtraction with regrouping algorhythm. A seven-day remediation procedure, which may be used with the other basic operations, fades from the concrete to the symbolic mode. (CL)
Enriching Addition and Subtraction Fact Mastery through Games
ERIC Educational Resources Information Center
Bay-Williams, Jennifer M.; Kling, Gina
2014-01-01
The learning of "basic facts"--single-digit combinations for addition, subtraction, multiplication, and division--has long been a focus of elementary school mathematics. Many people remember completing endless worksheets, timed tests, and flash card drills as they attempted to "master" their basic facts as children. However,…
Symmetric point quartic gluon vertex and momentum subtraction
NASA Astrophysics Data System (ADS)
Gracey, J. A.
2014-07-01
We compute the full one loop correction to the quartic vertex of QCD at the fully symmetric point. This allows us to define a new momentum subtraction (MOM) scheme in the class of schemes introduced by Celmaster and Gonsalves. Hence using properties of the renormalization group equation, the two loop renormalization group functions for this scheme are given.
Addition and Subtraction by Students with Down Syndrome
ERIC Educational Resources Information Center
Herrera, Aurelia Noda; Bruno, Alicia; Gonzalez, Carina; Moreno, Lorenzo; Sanabria, Hilda
2011-01-01
We present a research report on addition and subtraction conducted with Down syndrome students between the ages of 12 and 31. We interviewed a group of students with Down syndrome who executed algorithms and solved problems using specific materials and paper and pencil. The results show that students with Down syndrome progress through the same…
Children's Understanding of the Relationship between Addition and Subtraction
ERIC Educational Resources Information Center
Gilmore, Camilla K.; Spelke, Elizabeth S.
2008-01-01
In learning mathematics, children must master fundamental logical relationships, including the inverse relationship between addition and subtraction. At the start of elementary school, children lack generalized understanding of this relationship in the context of exact arithmetic problems: they fail to judge, for example, that 12 + 9 - 9 yields…
ERIC Educational Resources Information Center
Arnold, Fred; And Others
1989-01-01
Explores the effect of "chaining" through the petitioning of relatives on the demand for future immigrant visas by Koreans and Filipinos. Presents analyses that derive different multipliers that may be used in estimating the effects of chain migration, including a Theoretical Multiplier, an Adjusted Multiplier, and a Projected Multiplier. (JS)
Circuit design for nuclear radiation test of CMOS multiplier chips
Lim, T.S.; Martin, R.L.; Hughes, H.L.
1986-09-01
This paper describes the design of a microprocessor-based electronic circuit to be used in testing the effects of nuclear radiation on a CMOS 8 x 8 multiplier chip. Knowledge of such effects is important for military and space applications of integrated circuits. The multiplier chip undergoing testing is attached to a DUT (device under test) board which is enclosed in a metal container. The container is then lowered to the cobalt 60 radiation source located at the bottom of a 15-ft-deep pool. The gamma-ray radiation test setup is schematically shown. The in-source test board containing the multiplier chip is attached to an 8085-based, single-board microcomputer (SDK-85) by a 30-ft multiconductor cable. Doses of gamma-ray radiation from cobalt 60 are applied in steps at increasing quantities until the multiplier chip, which is tested between doses, begins to malfunction. An 8085 assembly language program is used for functional test of the multiplier. The leakage current and the propagation delay time are also measured between doses.
Multiply imaged quasi-stellar objects in the Gaia survey
NASA Astrophysics Data System (ADS)
Finet, F.; Surdej, J.
2016-05-01
Aims: We report a study on the statistical properties of the multiply imaged quasi-stellar objects (QSOs) to be detected within the Gaia survey. Methods: We considered two types of potential deflectors, the singular isothermal sphere (SIS) and the singular isothermal ellipsoid (SIE), to estimate the number of multiply imaged quasars as well as the normalized distributions of the redshifts of the lensed sources and of their associated deflectors. We also investigated the distribution of the lensing events as a function of their angular size and apparent magnitude. We compared the Gaia survey for multiply imaged quasars to typical ground-based surveys and to an ideal survey that would be carried out with a perfect instrument from space. Results: Of the 6.64 × 105 QSOs brighter than G = 20 to be detected by Gaia, we expect the discovery of about 2886 multiply imaged sources, 450 of which are expected to be produced by a late-type galaxy. We expect only ~1600 of these multiply imaged quasars to have an angular separation between their images that is large enough to be resolved from seeing-limited observations, and ~80 of them to have more than two lensed images.
NASA Astrophysics Data System (ADS)
Costa, Miguel S.; Greenspan, Lauren; Oliveira, Miguel; Penedones, João; Santos, Jorge E.
2016-06-01
We consider solutions in Einstein-Maxwell theory with a negative cosmological constant that asymptote to global AdS 4 with conformal boundary {S}2× {{{R}}}t. At the sphere at infinity we turn on a space-dependent electrostatic potential, which does not destroy the asymptotic AdS behaviour. For simplicity we focus on the case of a dipolar electrostatic potential. We find two new geometries: (i) an AdS soliton that includes the full backreaction of the electric field on the AdS geometry; (ii) a polarised neutral black hole that is deformed by the electric field, accumulating opposite charges in each hemisphere. For both geometries we study boundary data such as the charge density and the stress tensor. For the black hole we also study the horizon charge density and area, and further verify a Smarr formula. Then we consider this system at finite temperature and compute the Gibbs free energy for both AdS soliton and black hole phases. The corresponding phase diagram generalizes the Hawking-Page phase transition. The AdS soliton dominates the low temperature phase and the black hole the high temperature phase, with a critical temperature that decreases as the external electric field increases. Finally, we consider the simple case of a free charged scalar field on {S}2× {{{R}}}t with conformal coupling. For a field in the SU(N ) adjoint representation we compare the phase diagram with the above gravitational system.
New design of an RSFQ parallel multiply accumulate unit
NASA Astrophysics Data System (ADS)
Kataeva, Irina; Engseth, Henrik; Kidiyarova-Shevchenko, Anna
2006-05-01
The multiply-accumulate unit (MAC) is a central component of a successive interference canceller, an advanced receiver for W-CDMA base stations. A 4 × 4 two's complement fixed point RSFQ MAC with rounding to 5 bits has been simulated using VHDL, and maximum performance is equal to 24 GMACS (giga-multiply-accumulates per second). The clock distribution network has been re-designed from a linear ripple to a binary tree network in order to eliminate the data dependence of the clock propagation speed and reduce the number of Josephson junctions in clock lines. The 4 × 4 bit MAC has been designed for the HYPRES 4.5 kA cm-2 process and its components have been experimentally tested at low frequency: the 5-bit combiner, using an exhaustive test pattern, had margins on DC bias voltage of ± 18%, and the 4 × 4 parallel multiplier had margins equal to ± 2%.
High performance dc-dc conversion with voltage multipliers
NASA Technical Reports Server (NTRS)
Harrigill, W. T.; Myers, I. T.
1974-01-01
The voltage multipliers using capacitors and diodes first developed by Cockcroft and Walton in 1932 were reexamined in terms of state of the art fast switching transistors and diodes, and high energy density capacitors. Because of component improvements, the voltage multiplier, used without a transformer, now appears superior in weight to systems now in use for dc-dc conversion. An experimental 100-watt 1000-volt dc-dc converter operating at 100 kHz was built, with a component weight of about 1 kg/kW. Calculated and measured values of output voltage and efficiency agreed within experimental error.
Spatial frequency multiplier with active linearly tapered slot antenna array
NASA Technical Reports Server (NTRS)
Simons, Rainee N.; Lee, Richard Q.
1994-01-01
A frequency multiplier with active linearly tapered slot antennas (LTSA's) has been demonstrated at the second harmonic frequency. In each antenna element, a GaAs monolithic microwave integrated circuit (MMIC) distributed amplifier is integrated with two LTSA's. The multiplier has a very wide bandwidth and large dynamic range. The fundamental-to-second harmonic conversion efficiency is 8.1 percent. The spatially combined second harmonic signal is 50 dB above the noise level. The design is suitable for constructing a large array using monolithic integration techniques.
Gain degradation and efficiencies of spiral electron multipliers
NASA Technical Reports Server (NTRS)
Judge, R. J. R.; Palmer, D. A.
1973-01-01
The characteristics of spiral electron multipliers as functions of accumulated counts were investigated. The mean gain of the multipliers showed a steady decline from about 100 million when new, to about one million after 100 billion events when biased in a saturation mode. For prolonged use in a space environment, improved life expectancy might be obtained with a varying bias voltage adjusted to maintain the gain comfortably above a given discrimination level. Pulse-height distributions at various stages of the lifetime and variations of efficiency with energy of detected electrons are presented.
Robust Background Subtraction with Foreground Validation for Urban Traffic Video
Cheung, S S; Kamath, C
2004-01-15
Identifying moving objects in a video sequence is a fundamental and critical task in many computer-vision applications. Background subtraction techniques are commonly used to separate foreground moving objects from the background. Most background subtraction techniques assume a single rate of adaptation, which is inadequate for complex scenes such as a traffic intersection where objects are moving at different and varying speeds. In this paper, we propose a foreground validation algorithm that first builds a foreground mask using a slow-adapting Kalman filter, and then validates individual foreground pixels by a simple moving object model, built using both the foreground and background statistics as well as the frame difference. Ground-truth experiments with urban traffic sequences show that our proposed algorithm significantly improves upon results using only Kalman filter or frame-differencing, and outperforms other techniques based on mixture of Gaussians, median filter, and approximated media filter.
Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients
Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul
2013-01-01
In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided. PMID:24340276
Multivariate Spatial Condition Mapping Using Subtractive Fuzzy Cluster Means
Sabit, Hakilo; Al-Anbuky, Adnan
2014-01-01
Wireless sensor networks are usually deployed for monitoring given physical phenomena taking place in a specific space and over a specific duration of time. The spatio-temporal distribution of these phenomena often correlates to certain physical events. To appropriately characterise these events-phenomena relationships over a given space for a given time frame, we require continuous monitoring of the conditions. WSNs are perfectly suited for these tasks, due to their inherent robustness. This paper presents a subtractive fuzzy cluster means algorithm and its application in data stream mining for wireless sensor systems over a cloud-computing-like architecture, which we call sensor cloud data stream mining. Benchmarking on standard mining algorithms, the k-means and the FCM algorithms, we have demonstrated that the subtractive fuzzy cluster means model can perform high quality distributed data stream mining tasks comparable to centralised data stream mining. PMID:25313495
ZAP - enhanced PCA sky subtraction for integral field spectroscopy
NASA Astrophysics Data System (ADS)
Soto, Kurt T.; Lilly, Simon J.; Bacon, Roland; Richard, Johan; Conseil, Simon
2016-05-01
We introduce Zurich Atmosphere Purge (ZAP), an approach to sky subtraction based on principal component analysis (PCA) that we have developed for the Multi Unit Spectrographic Explorer (MUSE) integral field spectrograph. ZAP employs filtering and data segmentation to enhance the inherent capabilities of PCA for sky subtraction. Extensive testing shows that ZAP reduces sky emission residuals while robustly preserving the flux and line shapes of astronomical sources. The method works in a variety of observational situations from sparse fields with a low density of sources to filled fields in which the target source fills the field of view. With the inclusion of both of these situations, the method is generally applicable to many different science cases and should also be useful for other instrumentation. ZAP is available for download at http://muse-vlt.eu/science/tools.
Contrast matching techniques for digital subtraction radiography: an objective evaluation.
Likar, B.; Bernard, R.; Pernus, F.
1996-01-01
Digital subtraction radiography (DSR) enables the detection of subtle early detrimental effects of periodontal disease as well as the evaluation of the effects of therapy. However, the differences between two radiographs due to alignment and contrast errors must be kept at minimum. In the present in vitro study we test the efficacy of three basic contrast correction methods in the reduction of contrast mismatches which can adversely affect a subtracted image. The ODTF (Optical Density Thickness Function) method, which is based on a function relating grey level values of the aluminium wedge image and the corresponding thickness of the wedge, induced less contrast correction error than the CDF (Cumulative Density Function) and the LSQA (Least Square Quadratic Approximation) methods. Moreover, CDF, ODTF, and LSQA functions obtained from the reference structure density distribution may be applied for objective contrast enhancements and for standardisation of image quality, while the ODTF function allows also bone change volume estimations. PMID:8947675
Self-mixing differential vibrometer based on electronic channel subtraction.
Donati, Silvano; Norgia, Michele; Giuliani, Guido
2006-10-01
An instrument for noncontact measurement of differential vibrations is developed, based on the self-mixing interferometer. As no reference arm is available in the self-mixing configuration, the differential mode is obtained by electronic subtraction of signals from two (nominally equal) vibrometer channels, taking advantage that channels are servo stabilized and thus insensitive to speckle and other sources of amplitude fluctuation. We show that electronic subtraction is nearly as effective as field superposition. Common-mode suppression is 25-30 dB, the dynamic range (amplitude) is in excess of 100 microm, and the minimum measurable (differential) amplitude is 20 nm on a B = 10 kHz bandwidth. The instrument has been used to measure vibrations of two metal samples kept in contact, revealing the hysteresis cycle in the microslip and gross-slip regimes, which are of interest in the study of friction induced vibration damping of gas turbine blades for aircraft applications. PMID:16983412
Noise Reduction using Frequency Sub-Band Adaptive Spectral Subtraction
NASA Technical Reports Server (NTRS)
Kozel, David
2000-01-01
A frequency sub-band based adaptive spectral subtraction algorithm is developed to remove noise from noise-corrupted speech signals. A single microphone is used to obtain both the noise-corrupted speech and the estimate of the statistics of the noise. The statistics of the noise are estimated during time frames that do not contain speech. These statistics are used to determine if future time frames contain speech. During speech time frames, the algorithm determines which frequency sub-bands contain useful speech information and which frequency sub-bands contain only noise. The frequency sub-bands, which contain only noise, are subtracted off at a larger proportion so the noise does not compete with the speech information. Simulation results are presented.
Multivariate spatial condition mapping using subtractive fuzzy cluster means.
Sabit, Hakilo; Al-Anbuky, Adnan
2014-01-01
Wireless sensor networks are usually deployed for monitoring given physical phenomena taking place in a specific space and over a specific duration of time. The spatio-temporal distribution of these phenomena often correlates to certain physical events. To appropriately characterise these events-phenomena relationships over a given space for a given time frame, we require continuous monitoring of the conditions. WSNs are perfectly suited for these tasks, due to their inherent robustness. This paper presents a subtractive fuzzy cluster means algorithm and its application in data stream mining for wireless sensor systems over a cloud-computing-like architecture, which we call sensor cloud data stream mining. Benchmarking on standard mining algorithms, the k-means and the FCM algorithms, we have demonstrated that the subtractive fuzzy cluster means model can perform high quality distributed data stream mining tasks comparable to centralised data stream mining. PMID:25313495
ERIC Educational Resources Information Center
Canobi, Katherine H.; Bethune, Narelle E.
2008-01-01
Three studies addressed children's arithmetic. First, 50 3- to 5-year-olds judged physical demonstrations of addition, subtraction and inversion, with and without number words. Second, 20 3- to 4-year-olds made equivalence judgments of additions and subtractions. Third, 60 4- to 6-year-olds solved addition, subtraction and inversion problems that…
Subtraction of Positive and Negative Numbers: The Difference and Completion Approaches with Chips
ERIC Educational Resources Information Center
Flores, Alfinio
2008-01-01
Diverse contexts such as "take away," comparison," and "completion" give rise to subtraction problems. The take-away interpretation of subtraction has been explored using two-colored chips to help students understand addition and subtraction of integers. This article illustrates how the difference and completion (or missing addend) interpretations…
Digital subtraction angiography in pediatric cerebrovascular occlusive disease
Faerber, E.N.; Griska, L.A.B.; Swartz, J.D.; Capitanio, M.A.; Popky, G.L.
1984-08-01
While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease.
Digital subtraction angiography of a persistent trigeminal artery variant.
Temizöz, Osman; Genchellac, Hakan; Unlü, Ercüment; Cağli, Bekir; Ozdemir, Hüseyin; Demir, M Kemal
2010-09-01
Persistent trigeminal artery variants are described as cerebellar arteries that directly originate from the precavernous segment of the internal carotid artery. This has been observed in 0.18% of cerebral catheter angiograms. On the other hand, a persistent trigeminal artery variant feeding both the anterior inferior cerebellar artery and the posterior inferior cerebellar artery territory is very rare. We present this uncommon anomalous artery along with digital subtraction angiography findings and discuss its clinical significance in light of the literature. PMID:19821254
Diagnosis of Cardiovascular Disease by Digital Subtraction Angiography
NASA Astrophysics Data System (ADS)
Mistretta, Charles A.; Crummy, Andrew B.
1981-11-01
Recent advances in real-time digital video processing have led to a practical method for intravenous arteriography. The digital subtraction technique, which detects small differences in the concentration of the iodinated contrast material injected, is relatively safe and does not usually require hospitalization of the patient. The technique can thus be used for serial evaluation of various clinical problems and for studying the natural history of certain disease processes, as well as for following therapeutic endeavors.
Evaluation of vascular rings with digital subtraction angiography.
Tonkin, I L; Gold, R E; Moser, D; Laster, R E
1984-06-01
Seven patients with vascular rings were evaluated over a 2-year period with intravenous digital subtraction angiography (DSA), which was compared with screen-film aortography or cineangiography. The seven patients were also evaluated with barium esophagography. Six of the seven DSA images were totally diagnostic and one study was only partly diagnostic. Six of the seven vascular anomalies were confirmed surgically. DSA is suggested as an alternative to arteriography in evaluating patients with suspected vascular rings. PMID:6372419
Subtractive Renormalization Group Invariance: Pionless EFT at NLO
Timoteo, Varese S.; Szpigel, Sergio; Duraes, Francisco O.
2010-11-12
We show some results concerning the renormalization group (RG) invariance of the nucleon-nucleon (NN) interaction in pionless effective field theory at next-to-leading order (NLO), using a non-relativistic Callan-Symanzik equation (NRCS) for the driving term of the Lippmann-Schwinger (LS) equation with three recursive subtractions. The phase-shifts obtained for the RG evolved potential are same as those for the original potential, apart from relative differences of order 10{sup -15}.
IMPROVED BACKGROUND SUBTRACTION FOR THE SLOAN DIGITAL SKY SURVEY IMAGES
Blanton, Michael R.; Kazin, Eyal; Muna, Demitri; Weaver, Benjamin A.; Price-Whelan, Adrian
2011-07-15
We describe a procedure for background subtracting Sloan Digital Sky Survey (SDSS) imaging that improves the resulting detection and photometry of large galaxies on the sky. Within each SDSS drift scan run, we mask out detected sources and then fit a smooth function to the variation of the sky background. This procedure has been applied to all SDSS-III Data Release 8 images, and the results are available as part of that data set. We have tested the effect of our background subtraction on the photometry of large galaxies by inserting fake galaxies into the raw pixels, reanalyzing the data, and measuring them after background subtraction. Our technique results in no size-dependent bias in galaxy fluxes up to half-light radii r{sub 50} {approx} 100 arcsec; in contrast, for galaxies of that size the standard SDSS photometric catalog underestimates fluxes by about 1.5 mag. Our results represent a substantial improvement over the standard SDSS catalog results and should form the basis of any analysis of nearby galaxies using the SDSS imaging data.
Application of spectral subtraction method on enhancement of electrolarynx speech.
Liu, Hanjun; Zhao, Qin; Wan, Mingxi; Wang, Supin
2006-07-01
Although electrolarynx (EL) serves as an important method of phonation for the laryngectomees, the resulting speech is of poor intelligibility due to the presence of a steady background noise caused by the instrument, even worse in the case of additive noise. This paper investigates the problem of EL speech enhancement by taking into account the frequency-domain masking properties of the human auditory system. One approach is incorporating an auditory masking threshold (AMT) for parametric adaptation in a subtractive-type enhancement process. The other is the supplementary AMT (SAMT) algorithm, which applies a cross-correlation spectral subtraction (CCSS) approach as a post-processing scheme to enhancing EL speech dealt with the AMT method. The performance of these two algorithms was evaluated as compared to the power spectral subtraction (PSS) algorithm. The best performance of EL speech enhancement was associated with the SAMT algorithm, followed by the AMT algorithm and the PSS algorithm. Acoustic and perceptual analyses indicated that the AMT and SAMT algorithms achieved the better performances of noise reduction and the enhanced EL speech was more pleasant to human listeners as compared to the PSS algorithm. PMID:16875235
ROBUST TECHNIQUES FOR BACKGROUND SUBTRACTION IN URBAN TRAFFIC VIDEO
Kamath, C; Cheung, S S
2003-10-28
Identifying moving objects from a video sequence is a fundamental and critical task in many computer-vision applications. A common approach is to perform background subtraction, which identifies moving objects from the portion of a video frame that differs significantly from a background model. There are many challenges in developing a good background subtraction algorithm. First, it must be robust against changes in illumination. Second, it should avoid detecting non-stationary background objects such as swinging leaves, rain, snow, and shadow cast by moving objects. Finally, its internal background model should react quickly to changes in background such as starting and stopping of vehicles. In this paper, we compare various background subtraction algorithms for detecting moving vehicles and pedestrians in urban traffic video sequences. We consider approaches varying from simple techniques such as frame differencing and adaptive median filtering, to more sophisticated probabilistic modeling techniques. While complicated techniques often produce superior performance, our experiments show that simple techniques such as adaptive median filtering can produce good results with much lower computational complexity.
Palma, B. A.; Rosado-Mendez, I.; Villasenor, Y.; Brandan, M. E.
2010-02-15
This phantom study simulates contrast-medium-enhanced digital subtraction mammography (CEDM) and compares subtracted image quality and total mean glandular dose for two alternative spectral combinations available in a GE Senographe DS mammography unit. The first choice takes advantage of large iodine attenuation at low photon energies and uses traditionally available spectra (anode/filter combinations Mo/Mo at 25 kV and Rh/Rh at 40 kV, ''Mo25-Rh40''). The second choice, selected from a previous analytical optimization, includes harder spectra obtained by adding external filtration to traditional beams (Rh/Rh at 34 kV and Rh/Rh+5 mm of Al at 45 kV, ''Rh34-Rh45H''). Individual images of a custom-made phantom containing tubes of various diameters filled with water- or iodine-based contrast agent were acquired with both spectral combinations. The total breast entrance air kerma, considering subtraction of two images, was limited to 8.76 mGy (1 R). The results were compared to predictions obtained through an analytical formalism that assumes noise of stochastic origin. Individual images were evaluated and subtracted under five combinations of temporal and dual-energy modalities. Signal variance analysis in individual raw images showed important contributions of nonstochastic origin, associated with the software applied to raw images, the curved geometry, and strong attenuation of the phantom cylindrical iodine-filled tubes, causing experimental SNR to vary from 2.2 to 0.8 times the predictions from low to high values of SNR. Iodine contrast in the subtracted images was found to be mainly defined by the spectra, independent of exposure, and linearly dependent on the iodine mass thickness. The highest contrast was obtained with the combined dual-energy temporal subtraction with Rh34-Rh45H, its value was 7% larger than the highest value measured with Mo25-Rh40. As expected, temporal modalities (single and dual energy, any spectral choice) led to higher contrast
Functional Sign Training for the Severely Multiply Handicapped.
ERIC Educational Resources Information Center
Waldo, Lois; And Others
A training manual for teaching functional sign training to the severely multiply handicapped was developed using the Signing Exact English (SEE) system. The program, which was adapted from the Functional Speech and Language Training Program, is designed for persons who lack refined motor, speech, and language skills. Procedures are outlined to use…
Fabrication of Multi-Ply Birefringent Fibrous Composite Laminates
NASA Technical Reports Server (NTRS)
Daniel, I.; Niiro, T.
1984-01-01
Fabrication method produces unidirectional, multi-ply, transparent birefringent fibrous composite laminates for use in macromechanical stress analysis conducted by means of anisotropic photoelasticity. New laminates glass-fiber-reinforced plastics for which matrix and fibers have same index of refraction. Method utilized in structural applications of composites.
Familiar Sports and Activities Adapted for Multiply Impaired Persons.
ERIC Educational Resources Information Center
Schilling, Mary Lou, Ed.
1984-01-01
Means of adapting some familiar and popular physical activities for multiply impaired persons are described. Games reviewed are dice baseball, one base baseball, in-house bowling, wheelchair bowling, ramp bowling, swing-ball bowling, table tennis, shuffleboard, beanbag bingo and tic-tac-toe, balloon basketball, circle football, and wheelchair…
Multiply-Constrained Semantic Search in the Remote Associates Test
ERIC Educational Resources Information Center
Smith, Kevin A.; Huber, David E.; Vul, Edward
2013-01-01
Many important problems require consideration of multiple constraints, such as choosing a job based on salary, location, and responsibilities. We used the Remote Associates Test to study how people solve such multiply-constrained problems by asking participants to make guesses as they came to mind. We evaluated how people generated these guesses…
Improved channel multiplier for radiation-and-particle detectors
NASA Technical Reports Server (NTRS)
Schmidt, K. C.
1975-01-01
Multiplier is formed of glass and includes cylindrically-shaped main channel element having length-to-diameter ratio of 50 to 1. Element has open slot along its length. Attached to slot edges are two glass plates set at an angle to each other. Inside surfaces are coated with secondary electron emissive coating.
Medium power voltage multipliers with a large number of stages
NASA Technical Reports Server (NTRS)
Harrigill, W. T.; Myers, I. T.
1978-01-01
Voltage multiplier techniques are extended at medium power levels to larger multiplication ratios. A series of dc-dc converters were built, with from 20 to 45 stages and with power levels up to 100 watts. Maximum output voltages were about 10,000 volts.
Multiply-Impaired Blind Children: A National Problem.
ERIC Educational Resources Information Center
Graham, Milton D.
In 1966, a national survey reported on 8,887 multiply impaired (MI) blind children. About 56% were boys; 85% had been blind since before age 3, and half were totally blind. The principal causes of blindness were retrolental fibroplasia and congenital cataracts. Almost 63% had two or more additional disabilities (86.8% of those under age 6), such…
Cooking Skills Instruction with Severely Multiply Handicapped Adolescents.
ERIC Educational Resources Information Center
Horsfall, Debbie; Maggs, Alex
1986-01-01
Examination of the acquisition, maintenance, and generalization of three cooking skills by three multiply and severely handicapped blind adolescents revealed that a "whole task" approach was successful in teaching the subjects to boil an egg, grill cheese, and cook a TV dinner. These skills also generalized to other cooking products. (Author/CB)
Interactions of multiply-charged ions with electrons and photons
Gregory, D.C.; Johnson, B.M.; Jones, K.W.
1980-01-01
The current status of ion beam excitation and ionization by high energy electrons and photons is discussed. Recent advances in multiply-charged ion source development are mentioned, and plans for electron-ion and synchrotron-ion crossed beam experiments at Brookhaven National Laboratory are described.
Fixed-Tuned Submillimeter Waveguide Multipliers Using MMIC Technology
NASA Technical Reports Server (NTRS)
Bruston, J.; Kim, M.; Martin, S. C.; Pease, A.; Smith, R. P.; Siegel, P. H.
1997-01-01
In preparation for the insturment ammouncement of opportunity for the Far Infrared and Submillimeter Space Telescope, and ESA/NASA space astrophysics observatory mission, local oscillator sources at high frequencies (1200 GHz) are being developed. As part of a multiplier chain beginning at 100 GHz we are developing single and multiple diode waveguide circuits up to 640 GHz.
Problems with Accurate Atomic Lfetime Measurements of Multiply Charged Ions
Trabert, E
2009-02-19
A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest to remain cautious about the systematic errors of experimental techniques.
The structure of Airy's stress function in multiply connected regions
NASA Technical Reports Server (NTRS)
Grioli, Giusippe
1951-01-01
In solving two-dimensional problems using Airy's stress function for multiply connected regions, the form of the function depends on the dislocations and boundary forces present. The structure of Airy's function is shown to consist of a part expressible in terms of boundary forces and a part expressible in the manner of Poincare. Meanings of the constants occurring in Poincare's expression are discussed.
Gilles de la Tourette Disease in Multiply Disabled Children.
ERIC Educational Resources Information Center
Kerbeshian, Jacob; And Others
1985-01-01
Giles de La Tourette disease (TD) is characterized by multiform changing vocal and motor tics with a wide range of accompanying behavioral symptoms. The range of tics and behavioral problems seen in TD is described along with a typcial case report in a multiply disabled child. Diagnostic criteria, and treatment recommendations are also given.…
Multiplying Is More than Math--It's Also Good Management
ERIC Educational Resources Information Center
Foster, Elise; Wiseman, Liz
2015-01-01
Studying more than 400 educational leaders, the authors propose a new model for leadership and management rooted in the belief that there is latent intelligence inside schools and educational organizations. Their findings suggest two dramatically different types of leaders, Multipliers and Diminishers. The five disciplines that distinguish…
Quasi-optical overmoded waveguide frequency multiplier grid arrays
NASA Astrophysics Data System (ADS)
Rosenau, Steven Andrew
There is a growing need for compact, lightweight, inexpensive high power millimeter wave sources. Frequency multipliers can provide these sources by efficiently converting high power microwave signals to millimeter frequencies. Quasi-optical frequency multiplier grid arrays, comprised of hundreds to thousands of varactor devices and antennas on a single wafer, utilize spatial power combining to significantly increase power handling capability beyond that of a single device. In this dissertation work, theoretical and experimental investigations of frequency multiplier grid arrays have been conducted with a specific focus on overmoded waveguide systems. The principles of frequency multipliers and quasi-optical grid array power combining are presented. Simulation, design and experimental measurement techniques are described for both frequency tripler and doubler grid arrays. During this dissertation work, several quantum barrier varactor frequency tripler grid array systems and Schottky varactor frequency doubler grid array systems were designed, fabricated and tested. A frequency tripler grid array system, containing an innovative integrated output structure, achieved a multiplication efficiency of 3.4% and an output power of 148 mW. The two most efficient frequency doubler grid array systems achieved 11.7% multiplication efficiency and 0.41 W output power.
Ramos Alvarenga, René F; Friesen, J Brent; Nikolić, Dejan; Simmler, Charlotte; Napolitano, José G; van Breemen, Richard; Lankin, David C; McAlpine, James B; Pauli, Guido F; Chen, Shao-Nong
2014-12-26
This study introduces a flexible and compound targeted approach to Deplete and Enrich Select Ingredients to Generate Normalized Extract Resources, generating DESIGNER extracts, by means of chemical subtraction or augmentation of metabolites. Targeting metabolites based on their liquid-liquid partition coefficients (K values), K targeting uses countercurrent separation methodology to remove single or multiple compounds from a chemically complex mixture, according to the following equation: DESIGNER extract = total extract ± target compound(s). Expanding the scope of the recently reported depletion of extracts by immunoaffinity or solid phase liquid chromatography, the present approach allows a more flexible, single- or multi-targeted removal of constituents from complex extracts such as botanicals. Chemical subtraction enables both chemical and biological characterization, including detection of synergism/antagonism by both the subtracted targets and the remaining metabolite mixture, as well as definition of the residual complexity of all fractions. The feasibility of the DESIGNER concept is shown by K-targeted subtraction of four bioactive prenylated phenols, isoxanthohumol (1), 8-prenylnaringenin (2), 6-prenylnaringenin (3), and xanthohumol (4), from a standardized hops (Humulus lupulus L.) extract using specific solvent systems. Conversely, adding K-targeted isolates allows enrichment of the original extract and hence provides an augmented DESIGNER material. Multiple countercurrent separation steps were used to purify each of the four compounds, and four DESIGNER extracts with varying depletions were prepared. The DESIGNER approach innovates the characterization of chemically complex extracts through integration of enabling technologies such as countercurrent separation, K-by-bioactivity, the residual complexity concepts, as well as quantitative analysis by (1)H NMR, LC-MS, and HiFSA-based NMR fingerprinting. PMID:25437744
Locksley, R M; Cohen, M L; Quinn, T C; Tompkins, L S; Coyle, M B; Kirihara, J M; Counts, G W
1982-09-01
A burn patient with a multiply antibiotic-resistant Staphylococcus aureus infection was transferred to Harborview Medical Center from a burn unit in another state. Despite standard wound precautions, transmission to 34 patients occurred during the subsequent 15 months. Twenty-seven of the patients were infected. Disease included pneumonia, empyema, bacteremia, endocarditis, osteomyelitis, and burn and wound infections. Seventeen of the 34 patients died. Phage typing and plasmid analysis showed the spread of multiply resistant S. aureus from the burn unit to the surgical intensive care unit where a study evaluating the use of chloramphenicol in cases of bowel sepsis was in progress. During this period the organism became resistant to chloramphenicol by acquiring either of two chloramphenicol R-plasmids. Using plasmid profiles and antibiograms, four epidemic strains were identified that assisted in identifying patient and personnel reservoirs. The outbreak was controlled only after rifampin was added to vancomycin treatment of infected patients, which correlated with eradication of the carrier state. PMID:7114628
Temporal subtraction contrast-enhanced dedicated breast CT
NASA Astrophysics Data System (ADS)
Gazi, Peymon M.; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M.
2016-09-01
The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0–16%), NCC (0–6%), NMI (0–13%) and TRE (0–34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was
Temporal subtraction contrast-enhanced dedicated breast CT.
Gazi, Peymon M; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M
2016-09-01
The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0-16%), NCC (0-6%), NMI (0-13%) and TRE (0-34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was
Improvement of detection in computed radiography by new single-exposure dual-energy subtraction
NASA Astrophysics Data System (ADS)
Itoh, Wataru; Shimura, Kazuo; Nakajima, Nobuyoshi; Ishida, Masamitsu; Kato, Hisatoyo
1992-06-01
It is reported that the use of the dual-energy subtraction method enhances the abnormal shadow detection capability. However, as the subtracted image is significantly inferior to the original in signal-to-noise ratio (SNR), the x ray dosage normally used for chest x rays has not yielded subtracted images with adequate SNRs. Under these circumstances, we have concentrated on the fact that there is a correlation between the noise contents of bone and soft- tissue subtracted images although there is no correlation between the signal contents of these images. We now propose an algorithm that improves SNRs of subtraction images by reducing the noise only.
Smeared antibranes polarise in AdS
NASA Astrophysics Data System (ADS)
Gautason, Fridrik Freyr; Truijen, Brecht; Van Riet, Thomas
2015-07-01
In the recent literature it has been questioned whether the local backreaction of antibranes in flux throats can induce a perturbative brane-flux decay. Most evidence for this can be gathered for D6 branes and D p branes smeared over 6 - p compact directions, in line with the absence of finite temperature solutions for these cases. The solutions in the literature have flat worldvolume geometries and non-compact transversal spaces. In this paper we consider what happens when the worldvolume is AdS and the transversal space is compact. We show that in these circumstances brane polarisation smoothens out the flux singularity, which is an indication that brane-flux decay is prevented. This is consistent with the fact that the cosmological constant would be less negative after brane-flux decay. Our results extend recent results on AdS7 solutions from D6 branes to AdS p+1 solutions from D p branes. We show that supersymmetry of the AdS solutions depend on p non-trivially.
AdS orbifolds and Penrose limits
Alishahiha, Mohsen; Sheikh-Jabbari, Mohammad M.; Tatar, Radu
2002-12-09
In this paper we study the Penrose limit of AdS{sub 5} orbifolds. The orbifold can be either in the pure spatial directions or space and time directions. For the AdS{sub 5}/{Lambda} x S{sup 5} spatial orbifold we observe that after the Penrose limit we obtain the same result as the Penrose limit of AdS{sub 5} x S{sup 5}/{Lambda}. We identify the corresponding BMN operators in terms of operators of the gauge theory on R x S{sup 3}/{Lambda}. The semi-classical description of rotating strings in these backgrounds have also been studied. For the spatial AdS orbifold we show that in the quadratic order the obtained action for the fluctuations is the same as that in S{sup 5} orbifold, however, the higher loop correction can distinguish between two cases.
Skycorr: A general tool for spectroscopic sky subtraction
NASA Astrophysics Data System (ADS)
Noll, S.; Kausch, W.; Kimeswenger, S.; Barden, M.; Jones, A. M.; Modigliani, A.; Szyszka, C.; Taylor, J.
2014-07-01
Context. Airglow emission lines, which dominate the optical-to-near-infrared sky radiation, show strong, line-dependent variability on time scales from minutes to decades. Therefore, the subtraction of the sky background in the affected wavelength regime becomes a problem if plain-sky spectra have to be taken at a different time from the astronomical data. Aims: A solution of this problem is the physically motivated scaling of the airglow lines in the plain-sky data to fit the sky lines in the object spectrum. We have developed a corresponding instrument-independent approach based on one-dimensional spectra. Methods: Our code skycorr separates sky lines and sky/object continuum by an iterative approach involving a line finder and airglow line data. The sky lines, which mainly belong to OH and O2 bands, are grouped according to their expected variability. The line groups in the sky data are then scaled to fit the sky in the science data. Required pixel-specific weights for overlapping groups are taken from a comprehensive airglow model. Deviations in the wavelength calibration are corrected for by fitting Chebyshev polynomials and rebinning via asymmetric damped sinc kernels. The scaled sky lines and the sky continuum are subtracted separately. Results: ESO-VLT X-shooter data covering 2.5 h with a good time resolution were selected to illustrate the performance. Data taken six nights and about one year before were also used as reference sky data. The variation of the sky-subtraction quality as a function of time difference between the object and sky data depends on changes in the airglow intensity, atmospheric transparency, and instrument calibration. Except for short time intervals of a few minutes, the sky line residuals were between 2.1 and 5.5 times weaker than for sky subtraction without fitting. Additional tests showed that skycorr performs consistently better than the method of Davies (2007, MNRAS, 375, 1099) developed for ESO-VLT SINFONI data.
Peripheral NN scattering from subtractive renormalization of chiral interactions
Batista, E. F.; Szpigel, S.; Timóteo, V. S.
2014-11-11
We apply five subtractions in the Lippman-Schwinger (LS) equation in order to perform a non-perturbative renormalization of chiral N3LO nucleon-nucleon interactions. Here we compute the phase shifts for the uncoupled peripheral waves at renormalization scales between 0.1 fm{sup −1} and 1 fm{sup −1}. In this range, the results are scale invariant and provide an overall good agreement with the Nijmegen partial wave analysis up to at least E{sub lab} = 150 MeV, with a cutoff at Λ = 30 fm{sup −1}.
Background subtraction system for pulsed neutron logging of earth boreholes
Hertzog, R.C.
1980-11-04
The composition of an earth formation is investigated by repetitively irradiating the formation with bursts of fast neutrons and generating an inelastic energy spectrum from gamma ray counts detected during first time intervals which are contemporaneous with the bursts. A second energy spectrum is generated from gamma ray counts detected during second time intervals which immediately follow respective first time intervals. Gamma ray counts comprising the second spectrum are thereafter subtracted from the gamma ray counts comprising the inelastic spectrum to provide an inelastic energy spectrum with reduced background.
WFPC2 photometry from subtraction of TinyTim PSFs
NASA Technical Reports Server (NTRS)
Remy, M.; Surdej, J.; Baggett, S.; Wiggs, M.
1997-01-01
Based upon the subtraction of TinyTim Point Spread Function (PSFs) from Principle Component Image (PC1) point-like objects, a method has been developed to determine the optimal values for the telescope jitter and the Z4 relative focus during calibration or science observations. Using these jitter and focus values, an optimal TinyTim PSF, computed over a resampled grid, is then iteratively fitted to the object, yielding an improvement in the PSF centering, more accurate photometric results and a better detection of underlying structures. Preliminary results seem to indicate that appropriate synthetic TinyTim PSFs perform as well as observed PSFs.
Addition and subtraction by students with Down syndrome
NASA Astrophysics Data System (ADS)
Noda Herrera, Aurelia; Bruno, Alicia; González, Carina; Moreno, Lorenzo; Sanabria, Hilda
2011-01-01
We present a research report on addition and subtraction conducted with Down syndrome students between the ages of 12 and 31. We interviewed a group of students with Down syndrome who executed algorithms and solved problems using specific materials and paper and pencil. The results show that students with Down syndrome progress through the same procedural levels as those without disabilities though they have difficulties in reaching the most abstract level (numerical facts). The use of fingers or concrete representations (balls) appears as a fundamental process among these students. As for errors, these vary widely depending on the students, and can be attributed mostly to an incomplete knowledge of the decimal number system.
Walking boosts your performance in making additions and subtractions
Anelli, Filomena; Lugli, Luisa; Baroni, Giulia; Borghi, Anna M.; Nicoletti, Roberto
2014-01-01
Previous research demonstrates that the processing of spatial information and numerical magnitude are strictly interwoven. Recent studies also provide converging evidence that number processing is influenced by body movements. In the present study we further investigate this issue by focusing on whether and how motions experienced with the whole body can influence arithmetical calculations. We asked participants to make additions or subtractions while experiencing leftward and rightward motions. Data revealed the emergence of a congruency effect between the orientation inferred by the type of arithmetical calculations and the type of motions experienced along an horizontal axis. PMID:25566137
Intravenous digital subtraction angiography in the investigation of intracranial disease
DeFilipp, G.J.; Pinto, R.S.; Lin, J.P.; Kricheff, I.I.
1983-07-01
Eighty-six patients who presented with a variety of intracranial lesions were examined with intravenous digital subtraction angiogrphy (IV-DSA). A grading system was used to evaluate the ability IV-DSA to answer specific diagnostic questions regarding intracranial tumors, vasospasm following subarachnoid hemorrhage, lesions of the sella, dural sinus occlusion, and post-therapeutic embolization. Eighty-four percent of the examinations provided clinically useful information. In 15% of the cases limited but useful information was obtained; only 1% of the examinations provided no useful information. We conclude that IV-DSA can routinely provide useful information in the evaluation of the variety of intracranial lesions described above.
Photoelectron Angular Distribution and Molecular Structure in Multiply Charged Anions
Xing, Xiaopeng; Wang, Xue B.; Wang, Lai S.
2009-02-12
Photoelectrons emitted from multiply charged anions (MCAs) carry information of the intramolecular Coulomb repulsion (ICR), which is dependent on molecular structures. Using photoelectron imaging, we observed the effects of ICR on photoelectron angular distributions (PAD) of the three isomers of benzene dicarboxylate dianions C6H4(CO2)22– (o-, m- and p-BDC2–). Photoelectrons were observed to peak along the laser polarization due to the ICR, but the anisotropy was the largest for p-BDC2–, followed by the m- and o-isomer. The observed anisotropy is related to the direction of the ICR or the detailed molecular structures, suggesting that photoelectron imaging may allow structural information to be obtained for complex multiply charged anions.
Theoretical performance of novel multipliers at millimeter and submillimeter wavelengths
NASA Technical Reports Server (NTRS)
Tolmunen, Timo J.; Frerking, Margaret A.
1991-01-01
A theoretical comparison of various low and high order multipliers for 200 GHz and 1 THz has been carried out. Novel diodes including single barrier varactors, barrier-intrinsic-n(+)diodes and high electron mobility varactors are shown to have excellent theoretical performance, comparable or better than the conventional Schottky varactors for single and double diode frequency multipliers at millimeter and submillimeter wavelengths, whereas quantum well diodes, since they suffer from high resistive losses, are shown to be less attractive. In comparison to the conventional Schottky varactor, these new diodes have some potential advantages in their characteristics such as a stronger nonlinearity or a special symmetry. For future optimization some general comments on these advantages as well as other factors affecting multiplication are given.
A magnetoplasmonic electrical-to-optical clock multiplier
NASA Astrophysics Data System (ADS)
Firby, C. J.; Elezzabi, A. Y.
2016-02-01
We propose and investigate an electrical-to-optical clock multiplier, based on a bismuth-substituted yttrium iron garnet (Bi:YIG) magnetoplasmonic Mach-Zehnder interferometer (MZI). Transient magnetic fields induce a precession of the magnetization vector of the Bi:YIG, which in turn modulates the nonreciprocal phase shift in the MZI arms, and hence the intensity at the output port. We show that the device is capable of modulation depth of 16.26 dB and has a tunable output frequency between 279.9 MHz and 5.6 GHz. Correspondingly, the input electrical modulation frequency can be multiplied by factors of up to 2.1 × 10 3 in the optical signal. Such a device is envisioned as a critical component in the development of hybrid electrical-optical circuitry.
Mass-dependent channel electron multiplier operation. [for ion detection
NASA Technical Reports Server (NTRS)
Fields, S. A.; Burch, J. L.; Oran, W. A.
1977-01-01
The absolute counting efficiency and pulse height distributions of a continuous-channel electron multiplier used in the detection of hydrogen, argon and xenon ions are assessed. The assessment technique, which involves the post-acceleration of 8-eV ion beams to energies from 100 to 4000 eV, provides information on counting efficiency versus post-acceleration voltage characteristics over a wide range of ion mass. The charge pulse height distributions for H2 (+), A (+) and Xe (+) were measured by operating the experimental apparatus in a marginally gain-saturated mode. It was found that gain saturation occurs at lower channel multiplier operating voltages for light ions such as H2 (+) than for the heavier ions A (+) and Xe (+), suggesting that the technique may be used to discriminate between these two classes of ions in electrostatic analyzers.
A generalized algorithm to design finite field normal basis multipliers
NASA Technical Reports Server (NTRS)
Wang, C. C.
1986-01-01
Finite field arithmetic logic is central in the implementation of some error-correcting coders and some cryptographic devices. There is a need for good multiplication algorithms which can be easily realized. Massey and Omura recently developed a new multiplication algorithm for finite fields based on a normal basis representation. Using the normal basis representation, the design of the finite field multiplier is simple and regular. The fundamental design of the Massey-Omura multiplier is based on a design of a product function. In this article, a generalized algorithm to locate a normal basis in a field is first presented. Using this normal basis, an algorithm to construct the product function is then developed. This design does not depend on particular characteristics of the generator polynomial of the field.
Real Km-synthesis via generalized Popov multipliers
NASA Technical Reports Server (NTRS)
Chiang, R. Y.; Safonov, M. G.
1992-01-01
The authors refine their H-infinity control designs presented at the 1990 and 1991 American Control Conference by introducing a new real Km-synthesis technique involving the use of generalized Popov multipliers. This multiplier technique substantially reduces, and in some cases may even eliminate altogether, the conservativeness associated with traditional Km-synthesis solutions in which all uncertainties are treated as complex, even when they arise from real parameters such as the masses and spring constants in the benchmark problem. The design results demonstrate how this approach permits a very precise analysis of the intrinsic tradeoffs between robustness, performance, and control energy requirements. Also included is an open-loop H-infinity prefilter design that makes it possible to address the command response shaping issue. The design concept has been applied to the benchmark problem no. 4 and successfully removes the initial undesired transient and cuts down the percent overshoot.
Mesh quality control for multiply-refined tetrahedral grids
NASA Technical Reports Server (NTRS)
Biswas, Rupak; Strawn, Roger
1994-01-01
A new algorithm for controlling the quality of multiply-refined tetrahedral meshes is presented in this paper. The basic dynamic mesh adaption procedure allows localized grid refinement and coarsening to efficiently capture aerodynamic flow features in computational fluid dynamics problems; however, repeated application of the procedure may significantly deteriorate the quality of the mesh. Results presented show the effectiveness of this mesh quality algorithm and its potential in the area of helicopter aerodynamics and acoustics.
Study of the electric field inside microchannel plate multipliers
Gatti, E.; Oba, K.; Rehak, P.
1982-01-01
Electric field inside high gain microchannel plate multipliers was studied. The calculations were based directly on the solution of the Maxwell equations applied to the microchannel plate (MCP) rather than on the conventional lumped RC model. The results are important to explain the performance of MCP's, (1) under a pulsed bias tension and, (2) at high rate conditions. The results were tested experimentally and a new method of MCP operation free from the positive ion feedback was demonstrated.
Comparison of indirect cost multipliers for vehicle manufacturing
Vyas, A.; Santini, D.; Cuenca, R.
2000-05-16
In the process of manufacturing and selling vehicles, a manufacturer incurs certain costs. Among these costs are those incurred directly as a part of manufacturing operations and those incurred indirectly in the processes of manufacturing and selling. The indirect costs may be production-related, such as R and D and engineering; business-related, such as corporate staff salaries and pensions; or retail-sales-related, such as dealer support and marketing. These indirect costs are recovered by allocating them to each vehicle. Under a stable, high-volume production process, the allocation of these indirect costs can be approximated as multipliers (or factors) applied to the direct cost of manufacturing. A manufacturer usually allocates indirect costs to finished vehicles according to a corporation-specific pricing strategy. Because the volumes of sales and production vary widely by model within a corporation, the internal corporate percent allocation of various accounting categories (such as profit or corporate overheat) can vary widely among individual models. Approaches also vary across corporations. For these purposes, an average value is constructed, by means of a generic representative method, for vehicle models produced at high volume. To accomplish this, staff at Argonne National Laboratory's (ANL's) Center for Transportation Research analyzed the conventional vehicle cost structure and developed indirect cost multipliers for passenger vehicles. This memorandum summarizes the results of an effort to compare and put on a common basis the cost multipliers used in ANL's electric and hybrid electric vehicle cost estimation procedures with those resulting from two other methodologies. One of the two compared methodologies is derived from a 1996 presentation by Dr. Chris Borroni-Bird of Chrysler Corporation, the other is by Energy and Environmental Analysis, Inc. (EEA), as described in a 1995 report by the Office of Technology Assessment (OTA), Congress of the United
The gas electron multiplier (GEM): Operating principles and applications
NASA Astrophysics Data System (ADS)
Sauli, Fabio
2016-01-01
Introduced by the author in 1997, The Gas Electron Multiplier (GEM) constitutes a powerful addition to the family of fast radiation detectors; originally developed for particle physics experiments, the device and has spawned a large number of developments and applications; a web search yields more than 400 articles on the subject. This note is an attempt to summarize the status of the design, developments and applications of the new detector.
Cleaning and activation of beryllium-copper electron multiplier dynodes.
NASA Technical Reports Server (NTRS)
Pongratz, M. B.
1972-01-01
Description of a cleaning and activation procedure followed in preparing beryllium-copper dynodes for electron multipliers used in sounding-rocket experiments to detect auroral electrons. The initial degreasing step involved a 5-min bath in trichloroethylene in an ultrasonic cleaner. This was followed by an ultrasonic rinse in methanol and by a two-step acid pickling treatment to remove the oxides. Additional rinsing in water and methanol was followed by activation in a stainless-steel RF induction oven.
L^p-Fourier multipliers with bounded powers
NASA Astrophysics Data System (ADS)
Lebedev, V. V.; Olevskii, A. M.
2006-06-01
We consider the space M_p(\\mathbb R^d) of L^p-Fourier multipliers and give a detailed proof of the following result announced by the authors in [10]: if \\varphi\\colon\\mathbbR^d\\to \\lbrack0, 2\\pi\\lbrack is a measurable function and \\Vert e^{in\\varphi}\\Vert _{M_p}=O(1), n\\in\\mathbb Z, for some p\
Equilibrium thermodynamics of multiply substituted isotopologues of molecular gases
NASA Astrophysics Data System (ADS)
Wang, Zhengrong; Schauble, Edwin A.; Eiler, John M.
2004-12-01
Isotopologues of molecular gases containing more than one rare isotope (multiply substituted isotopologues) can be analyzed with high precision (1σ <0.1 ‰), despite their low natural abundances (˜ ppm to ppt in air), and can constrain geochemical budgets of natural systems. We derive a method for calculating abundances of all such species in a thermodynamically equilibrated population of isotopologues, and present results of these calculations for O 2, CO, N 2, NO, CO 2, and N 2O between 1000 and 193 to 77 K. In most cases, multiply substituted isotopologues are predicted to be enriched relative to stochastic (random) distributions by ca. 1 to 2 ‰ at earth-surface temperatures. This deviation, defined as Δ i for isotopologue i, generally increases linearly with 1/T at temperatures ≤ 500 K. An exception is N 2O, which shows complex temperature dependences and 10's of per-mill enrichments or depletions of abundances for some isotopologues. These calculations provide a basis for discriminating between fractionations controlled by equilibrium thermodynamics and other sorts of isotopic fractionations in the budgets of atmospheric gases. Moreover, because abundances of multiply substituted isotopologues in thermodynamically equilibrated populations of molecules vary systematically with temperature, they can be used as geothermometers. Such thermometers are unusual in that they involve homogeneous rather than heterogeneous equilibria (e.g., isotopic distribution in gaseous CO 2 alone, rather than difference in isotopic composition between CO 2 and coexisting water). Also, multiple independent thermometers exist for all molecules having more than one multiply substituted isotopologue (e.g., thermometers based on abundances of 18O 13C 16O and 18O 12C 18O are independent); thus, temperatures estimated by this method can be tested for internal consistency.
A Novel Synthesizing Genetic Logic Circuit: Frequency Multiplier.
Chuang, Chia-Hua; Lin, Chun-Liang
2014-01-01
This paper presents a novel synthesizing genetic logic circuit design based on an existing synthetic genetic oscillator, which provides a function of frequency multiplier to synthesize a clock signal whose frequency is a multiple of that of the genetic oscillator. In the renowned literature, the synthetic genetic oscillator, known as a repressilator, has been successfully built in Escherichia coli to generate a periodic oscillating phenomenon through three repressive genes repress each other in a chain. On the basis of this fact, our proposed genetic frequency multiplier circuit utilizes genetic Buffers in series with a waveform-shaping circuit to reshape the genetic oscillation signal into a crisp logic clock signal. By regulating different threshold levels in the Buffer, the time length of logic high/low levels in a fundamental sinusoidal wave can be engineered to pulse-width-modulated (PWM) signals with various duty cycles. Integrating some of genetic logic XOR gates and PWM signals from the output of the Buffers, a genetic frequency multiplier circuit can be created and the clock signal with the integer-fold of frequency of the genetic oscillator is generated. The synthesized signal can be used in triggering the downstream digital genetic logic circuits. Simulation results show the applicability of the proposed idea. PMID:26356341
Nonlinear optical response of multiply ionized noble-gas atoms
NASA Astrophysics Data System (ADS)
Tarazkar(1, 3), Maryam; Romanov(2, 3), Dmitri; Levis(1, 3), Robert
2016-05-01
Calculation of dynamic polarizabilities and hyperpolarizabilities of ionized species using ab initio methods presents computational and conceptual difficulties, as these ionized species often have open-shell electronic system. We use multi-configurational self-consistent field (MCSCF) method with extended basis sets for calculating dynamic polarizability and second-order hyperpolarizabilities of atomic noble gases and their multiply charged cations in non-resonant regime. The calculations were performed at wavelengths ranging from about 100 nm to the red of the first multi-photon resonance all the way toward the static regime. The results were benchmarked to those of CCSD calculations for ions of even-number charge. The second-order hyperpolarizability coefficients were found to decrease when the electrons are progressively removed from the system. At higher ionization states, these coefficients become less dispersive as a function of wavelength. The values and even the signs of the γ (2) coefficients were found to depend on the spin of the ionic quantum state. Thus, for Ne+3 and Ne+4, in low-spin states (2 Pu, and 1 Sg, respectively) the sign of γ (2) is positive, whereas in high-spin states (4 Su, and 3 Pg) the sign is negative. The calculated hyperpolarizabilities of multiply ionized atoms relate to experiments on very bright high-order harmonic generation in multiply ionized plasmas.
Inferring polyploid phylogenies from multiply-labeled gene trees
Lott, Martin; Spillner, Andreas; Huber, Katharina T; Petri, Anna; Oxelman, Bengt; Moulton, Vincent
2009-01-01
Background Gene trees that arise in the context of reconstructing the evolutionary history of polyploid species are often multiply-labeled, that is, the same leaf label can occur several times in a single tree. This property considerably complicates the task of forming a consensus of a collection of such trees compared to usual phylogenetic trees. Results We present a method for computing a consensus tree of multiply-labeled trees. As with the well-known greedy consensus tree approach for phylogenetic trees, our method first breaks the given collection of gene trees into a set of clusters. It then aims to insert these clusters one at a time into a tree, starting with the clusters that are supported by most of the gene trees. As the problem to decide whether a cluster can be inserted into a multiply-labeled tree is computationally hard, we have developed a heuristic method for solving this problem. Conclusion We illustrate the applicability of our method using two collections of trees for plants of the genus Silene, that involve several allopolyploids at different levels. PMID:19715596
A Voltage Multiplier for the nEDM Experiment
NASA Astrophysics Data System (ADS)
Bouman, Nathaniel; Stanislaus, Shirantha; Valpo nEDM Team
2015-10-01
The nEDM experiment at Oak Ridge National Laboratory aims to search for the electric dipole moment of the neutron (nEDM) at the 10-28 level. The experiment is currently at the research and development phase. One of the variables proportional to the sensitivity of the measurement is the strength of the electric field in the measurement cell where the effect of an nEDM is to be generated. The design of the experiment calls for an electric field of 75 kV/cm in this cell. A unique voltage multiplier involving a variable capacitor has been proposed to achieve this large required electric field. Electrostatic calculations using two independent software packages, COMSOL and Field Precision, were carried out to study the feasibility of the proposed voltage multiplier. A prototype of the electrodes and the voltage multiplier whose size was 25% of full size was also built to verify the predictions of the electrostatic calculations. Results of the tests with the prototype and the electrostatic calculations, will be presented.
Iodine filter imaging system for subtraction angiography using synchrotron radiation
NASA Astrophysics Data System (ADS)
Umetani, K.; Ueda, K.; Takeda, T.; Itai, Y.; Akisada, M.; Nakajima, T.
1993-11-01
A new type of real-time imaging system was developed for transvenous coronary angiography. A combination of an iodine filter and a single energy broad-bandwidth X-ray produces two-energy images for the iodine K-edge subtraction technique. X-ray images are sequentially converted to visible images by an X-ray image intensifier. By synchronizing the timing of the movement of the iodine filter into and out of the X-ray beam, two output images of the image intensifier are focused side by side on the photoconductive layer of a camera tube by an oscillating mirror. Both images are read out by electron beam scanning of a 1050-scanning-line video camera within a camera frame time of 66.7 ms. One hundred ninety two pairs of iodine-filtered and non-iodine-filtered images are stored in the frame memory at a rate of 15 pairs/s. In vivo subtracted images of coronary arteries in dogs were obtained in the form of motion pictures.
Background Subtraction Based on Three-Dimensional Discrete Wavelet Transform
Han, Guang; Wang, Jinkuan; Cai, Xi
2016-01-01
Background subtraction without a separate training phase has become a critical task, because a sufficiently long and clean training sequence is usually unavailable, and people generally thirst for immediate detection results from the first frame of a video. Without a training phase, we propose a background subtraction method based on three-dimensional (3D) discrete wavelet transform (DWT). Static backgrounds with few variations along the time axis are characterized by intensity temporal consistency in the 3D space-time domain and, hence, correspond to low-frequency components in the 3D frequency domain. Enlightened by this, we eliminate low-frequency components that correspond to static backgrounds using the 3D DWT in order to extract moving objects. Owing to the multiscale analysis property of the 3D DWT, the elimination of low-frequency components in sub-bands of the 3D DWT is equivalent to performing a pyramidal 3D filter. This 3D filter brings advantages to our method in reserving the inner parts of detected objects and reducing the ringing around object boundaries. Moreover, we make use of wavelet shrinkage to remove disturbance of intensity temporal consistency and introduce an adaptive threshold based on the entropy of the histogram to obtain optimal detection results. Experimental results show that our method works effectively in situations lacking training opportunities and outperforms several popular techniques. PMID:27043570
Fast Image Subtraction Using Multi-cores and GPUs
NASA Astrophysics Data System (ADS)
Hartung, Steven; Shukla, H.
2013-01-01
Many important image processing techniques in astronomy require a massive number of computations per pixel. Among them is an image differencing technique known as Optimal Image Subtraction (OIS), which is very useful for detecting and characterizing transient phenomena. Like many image processing routines, OIS computations increase proportionally with the number of pixels being processed, and the number of pixels in need of processing is increasing rapidly. Utilizing many-core graphical processing unit (GPU) technology in a hybrid conjunction with multi-core CPU and computer clustering technologies, this work presents a new astronomy image processing pipeline architecture. The chosen OIS implementation focuses on the 2nd order spatially-varying kernel with the Dirac delta function basis, a powerful image differencing method that has seen limited deployment in part because of the heavy computational burden. This tool can process standard image calibration and OIS differencing in a fashion that is scalable with the increasing data volume. It employs several parallel processing technologies in a hierarchical fashion in order to best utilize each of their strengths. The Linux/Unix based application can operate on a single computer, or on an MPI configured cluster, with or without GPU hardware. With GPU hardware available, even low-cost commercial video cards, the OIS convolution and subtraction times for large images can be accelerated by up to three orders of magnitude.
Intravenous Digital Subtraction Angiography (DSA) of Hemodialysis Access Fistulae
Allen, Gregory J.; Burnett, Keith R.; Vaziri, Nosratola D.; Friedenberg, Richard M.
1986-01-01
Hemodialysis access fistulae or grafts are subject to a variety of complications, including thrombosis, stenoses, and aneurysm or pseudoaneurysm formation. The usual radiologic methods to evaluate these problems consist of retrograde venous angiography or standard femoral or brachial arteriography. Both are invasive, and may traumatize the artery or graft. Six patients with internal blood access were studied using digital subtraction angiography; five using a central venous injection and one with direct graft injection. Preliminary results indicate that intravenous digital subtraction angiography (IV-DSA) can depict the anatomy of access fistula with adequate spatial resolution. Pathologic entities (stenoses, aneurysms) can be demonstrated, as well as other findings of uncertain clinical significance (kinks and webs). In addition, hemodynamic data can be inferred from the near-physiologic sequence of vessel opacification. Methods are in development that will allow determination of absolute blood flow in pertinent vessels via IV-DSA. There were no complications in this small series, and all examinations were performed on outpatients utilizing standard technique. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6 PMID:3537322
The research about the quick algorithm of subtracting the DTM
NASA Astrophysics Data System (ADS)
Chian, Tao; Li, Yan; Geng, Juan
2007-06-01
There is some relationship between the Digital Surface Model (DSM) and the Digital Terrain Model (DTM). The contents they express are relative: DSM expresses the height we focus on about the surface of the ground, including the terrain and the objects on it, and DTM only gives the height of the terrain excluding the objects above it. DSM have the information of DTM, therefore it provides us a chance to subtract the DTM from the DSM. Mathematical morphology is a new method applied to Imagery processing and pattern recognition fields. It provides an effective method of subtracting DTM from DSM. But in practical application, the original calculations of these two are in low efficiency. Especially when it comes to a large template or huge block data, the computation speed can be a very headache question. This paper is studying the implementing process of the Open and the Close operators, especially the Erode and the Dilate calculations. Then we have developed two kinds of quick algorithms, which are aim to avoid the repeated calculation, and to enhance the efficiency sharply. The step of the two operations also should be refined, while the disposals are different from each other depending on the distinct configuration of these two kinds of algorithms.
Quasinormal modes for subtracted rotating and magnetized geometries
NASA Astrophysics Data System (ADS)
Cvetič, M.; Gibbons, G. W.; Saleem, Z. H.
2014-12-01
We obtain explicit separable solutions of the wave equation of massless minimally coupled scalar fields in the subtracted geometry of four-dimensional rotating and Melvin (magnetised) four-charge black holes of the STU model, a consistent truncation of maximally supersymmetric supergravity with four types of electromagnetic fields. These backgrounds possess a hidden SL (2 ,R )×SL (2 ,R )×SO (3 ) symmetry and faithfully model the near-horizon geometry of these black holes, but locate them in a confining asymptotically conical box. For each subtracted geometry we obtain two branches of quasinormal modes, given in terms of hypergeometric functions and spherical harmonics. One branch is over-damped and the other under-damped and they exhibit rotational splitting. No black hole bomb is possible because the Killing field which corotates with the horizon is everywhere timelike outside the black hole. A five-dimensional lift of these geometries is given locally by the product of a Bañados-Teitelboim-Zanelli black hole with a two-sphere. This allows an explicit analysis of the minimally coupled massive five-dimensional scalar field. Again, there are two branches, both damped; however, now their oscillatory parts are shifted by the quantized wave number k along the fifth circle direction.
Background Subtraction Based on Three-Dimensional Discrete Wavelet Transform.
Han, Guang; Wang, Jinkuan; Cai, Xi
2016-01-01
Background subtraction without a separate training phase has become a critical task, because a sufficiently long and clean training sequence is usually unavailable, and people generally thirst for immediate detection results from the first frame of a video. Without a training phase, we propose a background subtraction method based on three-dimensional (3D) discrete wavelet transform (DWT). Static backgrounds with few variations along the time axis are characterized by intensity temporal consistency in the 3D space-time domain and, hence, correspond to low-frequency components in the 3D frequency domain. Enlightened by this, we eliminate low-frequency components that correspond to static backgrounds using the 3D DWT in order to extract moving objects. Owing to the multiscale analysis property of the 3D DWT, the elimination of low-frequency components in sub-bands of the 3D DWT is equivalent to performing a pyramidal 3D filter. This 3D filter brings advantages to our method in reserving the inner parts of detected objects and reducing the ringing around object boundaries. Moreover, we make use of wavelet shrinkage to remove disturbance of intensity temporal consistency and introduce an adaptive threshold based on the entropy of the histogram to obtain optimal detection results. Experimental results show that our method works effectively in situations lacking training opportunities and outperforms several popular techniques. PMID:27043570