ALLOCATION OF WEAPONS TO TARGETS WITH EXPONENTIAL ARRIVAL TIMES IN A LIMITED TIME INTERVAL

1963 ◽  
Author(s):  
J. Bram
Keyword(s):  
Time Interval ◽  
Limited Time ◽  
Arrival Times ◽  
Limited Time Interval

scholarly journals Modelling the Structure of the Ringed Spiral NGC 4736

1996 ◽  
Vol 157 ◽  
pp. 253-255
Author(s):  
Wim van Driel ◽  
Pieter Mulder ◽  
Françoise Combes
Keyword(s):  
Mass Distribution ◽  
Spiral Structure ◽  
Optical Spectra ◽  
Spectral Lines ◽  
Time Interval ◽  
Limited Time ◽  
The Galaxy ◽  
Dynamical Simulations ◽  
Pattern Speed ◽  
Limited Time Interval

AbstractWe studied the ringed RSab(r)-type spiral NGC 4736, which has a probably slightly oval disk and a very small bar. We mapped the galaxy in the HI and Hα spectral lines and we obtained long-slit optical spectra. These data were modeled using a 2-D gas dynamical code. The 2-D potential used is axisymmetric in the inner and outer regions and oval (b/a=0.8) at intermediate radii only. The oval component rotates at a pattern speed of 40 km s–1 kpc–1, close to the observed value. Inner and outer rings, like those observed, form at the inner and outer Lindblad resonances, though they co-exist only during a limited time interval in the simulations. The morphology and kinematics of the inner ring and spiral structure as observed in neutral and ionized hydrogen can be well understood in terms of gas dynamical simulations, given the form of the (stellar) potential. What remains to be explained is the origin of the nonaxisymmetric features in the mass distribution defining the potential.

Model Based Targets Matching from Image Frames

2011 ◽  
Vol 341-342 ◽  
pp. 748-752
Author(s):  
Xin Wang ◽  
Jin Wang
Keyword(s):  
Image Sequence ◽  
Image Point ◽  
Time Interval ◽  
Limited Time ◽  
Feature Points ◽  
Model Based ◽  
Moving Platform ◽  
Limited Time Interval

We present a new algorithm to locate targets by matching image frames taken from a moving platform. We have noticed that an image point is environment sensitive, but those energy changes of grouped points have their own statistical similarities in two image frames within limited time interval. This approach analyzes correspondence of energy points around every feature points between inter-frames in image sequence in order to decide those feature points. Successful results are given for a vide frames.

Resonant Wave-Particle Interaction in Nonuniform Plasmas

1971 ◽  
Vol 26 (9) ◽  
pp. 1528-1530
Author(s):  
L. Saitta ◽  
F. Engelmann
Keyword(s):  
Particle Interaction ◽  
Time Interval ◽  
Limited Time ◽  
Linear Dynamics ◽  
Wave Particle Interaction ◽  
Resonant Wave ◽  
Parabolic Potential ◽  
Resonant Effect ◽  
Special Case ◽  
Limited Time Interval

Abstract The appearance of resonant-particle effects in the linear dynamics of electron waves in a plasma whose electrons are trapped in a potential trough is discussed and conditions for the characteristic times involved are derived. For the special case of a parabolic potential trough it is shown that, within a limited time interval, a strong resonant effect may occur, due to the interaction of a wave with all particles, which is not contained in the solutions given so far.

scholarly journals Detection of Short-Step Pulses Using Practical Test-Functions and Resonance Aspects

2008 ◽  
Vol 2008 ◽  
pp. 1-15 ◽  
Author(s):  
Alexandru Toma ◽  
Cristian Morarescu
Keyword(s):  
Second Order ◽  
Order System ◽  
Time Interval ◽  
Limited Time ◽  
Large Step ◽  
Working Frequency ◽  
Second Order Systems ◽  
Intelligent Methods ◽  
Physical Quantities ◽  
Limited Time Interval

An important aspect in modeling dynamic phenomena consists in measuring with higher accuracy some physical quantities corresponding to the dynamic system. Yet for measurements performed on limited time interval at high working frequency, certain intelligent methods should be added. The high working frequency requires that the measurement and data processing time interval should be greater than the time interval when the step input is received, so as to allow an accurate measurement. This paper will show that an intelligent processing method based on oscillating second-order systems working on limited time interval can differentiate between large step inputs (which are active on the whole limited time interval) and short step inputs (which are active on a time interval shorter than the limited working period). Some resonance aspects (appearing when the input frequency is close to the working frequency of the oscillating second-order system) will be also presented.

scholarly journals Signal Processing and Sampling Method for Obtaining Time Series Corresponding to Higher Order Derivatives

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Andreea Sterian ◽  
Alexandru Toma
Keyword(s):  
Time Series ◽  
Dynamic System ◽  
Sampling Procedure ◽  
Higher Order ◽  
Time Interval ◽  
Limited Time ◽  
Time Intervals ◽  
Oscillating Systems ◽  
Robust Computation ◽  
Derivatives Of

For modeling and controlling dynamic phenomena it is important to establish with higher accuracy some significant quantities corresponding to the dynamic system. For fast phenomena, such significant quantities are represented by the derivatives of the received signals. In case of advanced computer modeling, the received signal should be filtered and converted into a time series corresponding to the estimated values for the dynamic system through a sampling procedure. This paper will show that present-day methods for computing in a robust manner the first derivative of a received signal (using an oscillating system working on a limited time interval and a supplementary differentiation method) can be extended to the robust computation of higher order derivatives of the received signal by using a specific set of second-order oscillating systems (working also on limited time intervals) so as estimative values for higher-order derivatives are to be directly generated (avoiding the necessity of additional differentiation or amplifying procedures, which represent a source of supplementary errors in present-day methods).

scholarly journals On the use of earthquake multiplets to study fractures and the temporal evolution of an active volcano

1996 ◽  
Vol 39 (2) ◽  
Author(s):  
G. Poupinet ◽  
A. Ratdomopurbo ◽  
O. Coutant
Keyword(s):  
Seismic Velocity ◽  
Active Volcano ◽  
Temporal Changes ◽  
Time Interval ◽  
Velocity Change ◽  
P Waves ◽  
Merapi Volcano ◽  
Arrival Times ◽  
Cross Spectrum ◽  
Window Technique

Multiplets, i.e. events with similar waveforms, are common features on active volcanoes. The seismograms of multiplets are analyzed by cross-spectrum techniques: this procedure improves by a factor of about 10 the precision of differential P-arrival times and therefore the accuracy of the relative location of earthquakes. Long period events which cannot be located because of the impossibility to pick up P-waves on individual seismograms can be located with a precision of about 10 m. Such a precision permits fault planes to be mapped inside a volcanic edifice and the azimuth and strike of fractures to be defined. Seismograms of the two events (of a doublet) that occur on different dates are analyzed by the Cross Spectrum Moving Window technique (CSMW) for measuring the time delay between waves in the coda. The pattern of the delays in the coda is a function of the temporal changes of seismic velocity that occurred inside the volcano during the time interval that separates the two events of a doublet. We illustrate the potential of the doublet technique for detecting temporal changes inside a volcano by performing computations of synthetic seismograms. The case of a dyke injected inside the volcano is considered as well as that of the replenishment of a superficial magma chamber and of a general increase in velocity in the summit of the volcano. Data from Merapi volcano (Indonesia)illustrate a possible temporal velocity change inside the volcano several months before the 1992 eruption.

A fall in P-wave velocity before the Gisborne, New Zealand, earthquake of 1966

1974 ◽  
Vol 64 (5) ◽  
pp. 1501-1507 ◽  
Author(s):  
D. J. Sutton
Keyword(s):  
New Zealand ◽  
Wave Velocity ◽  
Significant Variation ◽  
Arrival Time ◽  
P Wave ◽  
Time Interval ◽  
P Waves ◽  
Arrival Times ◽  
P Wave Velocity ◽  
Seismograph Station

Abstract A fall in P-wave velocity before the Gisborne earthquake of March 4, 1966 is indicated by arrival-time residuals of P waves from distant earthquakes recorded at the Gisborne seismograph station. Residuals were averaged over 6-month intervals from 1964 to 1968 and showed an increase of about 0.5 sec, implying later arrival times. The change began about 480 days before the earthquake. This precursory time interval is about that expected for an earthquake of this magnitude (ML = 6.2), but unlike most other reported instances, there was no obvious delay between the return of the velocity to normal and the occurrence of the earthquake. Similar analyses were carried out over the same period for two other New Zealand seismograph stations; at Karapiro there was no significant variation in mean residuals, and at Wellington the scatter was too large for the results to be meaningful. The Gisborne earthquake had a focus in the lower crust, about 25 km deep and was deeper than other events for which such precursory drops in P-wave velocity have been reported.

Sign in / Sign up

Export Citation Format

Share Document