52 results about "Passive Method" patented technology

A sound source localization method of a three-dimensional space adopts a movable small microphone array and a sound source localization technology based on time delay estimation. The small microphone array is used for collecting a period of target sound source signals, a mutual correlation algorithm is used for calculating time differences between the microphones of the small microphone array, the time differences are substituted into computational formulas of azimuth and elevation to get the azimuth and the elevation of the target sound source, and then the small microphone array is moved for some distance along a certain azimuth, and the operations are repeated to get the azimuth and the elevation of the target sound source at the moment. Through measuring the azimuth and the elevation of the target sound source twice, the distance of the target sound source is calculated. The method of measuring target sound source is a passive method. The small microphone array is moved during the measuring process, and the defects that accuracy of the sound source target distance measuring of the prior art is low, and cost is high and safety is not ensured due to the fact that an active method is adopted to measure the sound source target distance are overcome.

The invention relates to a network equipment type identification method and a system based on a decision tree, belonging to the technical field of network security. The method comprises the steps of collecting data flow of network equipment, preprocessing the network flow, extracting HTTP data packets from the flow, vectorizing the characteristic data of text type, and utilizing the characteristicvector to carry out decision tree. C45 classification, the final identification of the type of equipment; The invention can adopt a decision tree based on network traffic tree. C45 algorithm identifythat type of network device. The method is based on the passive method to detect the type of unknown device, which will not be captured by the intrusion detection system. At the same time, the type of unknown device can be recognized, and the type of unknown device can be added to the system to improve the generalization ability.

A passive method is provided as alignment means for aligning an optical fiber with an optical element in assembling an optical module, while increasing alignment accuracy. A mount (28a) equipped with an optical element (3a) is positioned by abutment on a face (33c) of a projection (33a) formed inside a package (33) and on a side (33g) of a positioning pad (37) projecting from the bottom (33f) of the package. A mount (28b) equipped with an optical element (3b) is positioned by abutment on an inner wall (33b) of the package and on a face (33i) of a projection (33c) formed inside the package. Since the optical power of received or emitted light need not be monitored for fine adjustments of alignment, this method is less expensive.

A waveguide for use in polarization mode converters and polarization modulators using extrinsic strain to prerotate the principal axes and control birefringence is disclosed herein. The invention relates to the orienting of principal propagation axes in an optical waveguide by pre-stressing the waveguide, using an extrinsic stress, to re-orient the principal propagation axes from an unstressed orientation to a substantially ideal orientation. The waveguide is preferably stressed by an extrinsic strain inducer which applies a shear force to the waveguide to induce anisometry in the waveguide structure.

Methods and apparatus are provided for controlling temperatures in the environments of oil, gas condensate, or gas wells. Methods are provided for reducing the melting of glaciers and ice dams through the deployment of hydrate-forming substances. Active methods involve employing a vapor-compression refrigerator/heat pump cycle in an annulus lying between the relatively hot production string and the relatively cold outer pipe. Passive methods include: deploying cold hydrate-forming fluids into the external ice-laden environment of an oil, gas condensate, or gas well in a permafrost area and allowing those hydrate forming fluids to mix with any melt-water that may be present or that may subsequently form due to the loss of heat from the oil, gas condensate, or gas well. Mixtures of the hydrate forming fluids and the melt-water will set up into a solid having a much higher melting point and a much lower thermal conductivity than those of ice.

The invention discloses a passive location method based on maximum likelihood to improve locating accuracy of a passive locating sensor. The purpose of the invention is to overcome the shortage, namely the disadvantage that freeness of setting a target initial value and low target location accuracy cannot be achieved at the same time, of a traditional passive target location method. The method comprises the following implementation steps of: firstly considering a passive locating condition in a two-dimensional space, and calculating initial position estimation of a target; calculating an auxiliary variable G1; structuring a new target position estimation formula in a two-dimensional space; estimating a z coordinate value of the target in a three-dimensional space; structuring a passive locating target function based on a maximum likelihood criterion; and carrying out iterative optimization to obtain an estimation result. According to the location method provided by the invention, the target initial position is not required and the accuracy of a location result is the same as that of a traditional maximal likelihood passive method.

Patch antennas for signals of global navigation satellite systems (GNSS) are described. A compact antenna system reduces directional diagram level in the rear hemisphere primarily for cross-polarized (left hand circularly-polarized) component. It can be used for reducing multipath reception. The antenna receives GNSS signals and includes a patch circularly-polarized radiator consisting of a radiating patch, a ground plane under it and a loop radiator coaxially located around the patch radiator. The loop radiator is excited by a separate power circuit or by a passive method where LHCP waves of MP and loop radiators in the rear hemisphere would be anti-phase added. A dual-band antenna system includes an active HF radiator, under which there is an active LF radiator under which there is a passive LF radiator, a loop HF radiator being coaxially located around the active HF radiator.

An indirect and passive method for AC/DC( converter power factor correction is disclosed. The correction is achieved by stabilizing the input impedance of the converter with keeping the inversely proportional dependence between the current i_conv(t) and voltage u_conv(t) of the output smoothing filter (3). The necessary dependence is achieved by natural characteristics of circuit with passive components. An uncontrolled converter (6) with alternation of parallel and series resonance is used as such circuit. To increase the operating frequency of this converter, a chopper or an inverter is used. The resonant converter decreases the commutation current of the switches. Output voltage is easy to control by pulse width modulation of chopper or inverter. Passive power factor correction results in the total harmonic distortion of main current THD_i=10 to 40 per cent. All currents of the converter are limited naturally in all operating modes.

Disclosed is a method to passively measure and calculate the strength of turbulence via the index of refraction structure constant C_n² from video imagery gathered by an imaging device, such as a video camera. Processing may occur with any type computing device utilizing a processor executing machine executable code stored on memory. This method significantly simplifies instrumentation requirements, reduces cost, and provides rapid data output. This method combines an angle of arrival methodology, which provides scale factors, with a new spatial/temporal frequency domain method. As part of the development process, video imagery from high speed cameras was collected and analyzed. The data was decimated to video rates such that statistics could be computed and used to confirm that this passive method accurately characterizes the atmospheric turbulence. C_n² accuracy from this method compared well with scintillometer data through two full orders of magnitude and more capability is expected beyond this verification.

The invention discloses an active and passive integrated mixed island detection method. DG system outputted active power P, load consumed active power P+deltaP and load consumed passive power deltaQ are calculated through data collection, a detection method is selected according to a passive blind area criterion, and in a blind area criterion, an SFS detection method in a non-blind area is adopted; an overvoltage/undervoltage and overfrequency/underfrequency device detection method is adopted outside a blind area, the defect that a passive method is large in blind area can be improved, and the non-blind area detection is achieved; since the possibility that in actual operation, a local load is in the passive blind area is low, the influence of the detection method on quality of electric energy can be reduced greatly.

The invention provides a method for achieving online inhabitation of processing fluttering through intelligent control of rotation speed of a spindle, and belongs to the field of intelligent processing. The method comprises steps of step 1, when a spindle is processed at the initial rotation speed of n0, carrying out real-time monitoring on milling processing states, analyzing detection results and determining whether fluttering occurs or not; and step 2, when failing to identifying occurrence of the fluttering, keeping the original rotation speed of the spindle of a machine tool unchanged, repeating execution of the step 1, and when identifying the occurrence of the fluttering, adjusting the rotation speed of the spindle to the new spindle optimal rotation speed nnew, and carrying out fluttering inhabitation at the early stage of the occurrence of the fluttering. According to the invention, online inhibition of fluttering in milling processing is achieved through intelligent control of the rotation speed of the spindle; when the fluttering is monitored, a numerical control machine tool will adjust the rotation speed of the spindle to be the new rotation speed nnew through which stable cutting can be achieved by use of an adaptive control algorithm provided by the invention, so problems and disadvantages in a passive method for inhibiting the fluttering based on random range of the rotation speed of the spindle in a certain range in a normal cutting process are solved.

An atmospheric refraction profile is determined using an imaging system positioned at a location that is simultaneously within line-of-sight of two celestial light sources. A variety of active or passive methods can be employed to cause the line-of-sight to vertically traverse through a refractive portion of an atmosphere. Images of the two celestial light sources are captured as the line-of-sight vertically traverses through the refractive portion of the atmosphere. Each such image indicates an apparent distance between the two celestial light sources. The apparent distances are used to determine refraction angles.

A passive method for protecting taut cables from vibrations comprising the perpendicularly attachment of a device comprising a unilateral spring or a shape memory alloy wire to a taut cable at an attachment position wherein the device (especially the unilateral spring of the shape memory alloy wire of the device) acts on the taut cable only when the vibrating taut cable exceeds a switch position (SP); a device for protecting a taut cable from vibrations, as well as the use of such a device in a construction.

This invention relates to a carrier generation device and a method for millimeter waves of RF fiber transmission system, in which, said device is composed of a semiconductor laser, a phase modulator, a sine wave drive of a central station, a periodical optical filter, a light detector and a millimeter wave band-pass filter of the base station, which utilizes the phase modulator, applies sine wave to carry out optical scanning to the output optical waves of the semiconductor laser at the central station and utilizes the transmission response wave characteristics of Fabry-Perot optical filter to convert the optical waves with varied frequencies to those with strength variance to get mm wave carriers via the optical detector and mm wave band pass filter, which can generate millimeter waves in the base station by a passive method.

A method for measuring wind velocity including using a Fourier Transform (FT) and a correlation between a wave vector number and temporal frequency of a wind to calculate wind velocity. Contour line deviations in a series of images of a far object are evaluated by performing a spatial discrete fourier transform (DFT) on deviations within each image, and subsequently a time discrete fourier transform (DFT) on the Fourier coefficients obtained by the spatial DFT, to get the frequency dependence of each Fourier coefficient.

The invention relates to a mixed island detection method based on a combination of a slide mode frequency shift method and a passive method. The method comprises that an inversion output current, a load current and related values are collected, and inversion output active power and reactive power and load consumption active power and reactive power of are calculated; according to a difference between the inversion output active power and the load consumption active power as well as a difference between the inversion output reactive power and the load consumption reactive power, an over/under frequency detection method in the passive method is used to obtain a reference current value, or the slide mode frequency shift method is used to obtain the reference current value. According to the invention, load change can be tracked, and different algorithms are switched in real time; switching mistakes of the island detection algorithms caused by instant voltage and current jump can be prevented; and blind detection areas can be reduced and the detection speed can be increased compared with those when the passive method is used independently, and THD of the power-grid current can be reduced compared with that only the slide-mode frequency shift method is used.

The invention relates to the technical field of hull manufacturing, in particular to a design method of a hull deck surface platform molded line. By using a geometrograph, the hull deck surface platform molded line is simple, convenient and easy to make; the finished molded line is smooth in three directions; helicopter landing platform performance requirements are satisfied; a solid guarantee isprovided for smooth assembling a landing grille on a slipway; and by using method for smoothening a molded deck line in the form of a square plate in advance, a passive method of squeezing the landingplatform on site is changed; and therefore, major reworking risk caused by not passing acceptance inspection in the later period is reduced, the hull manufacturing efficiency is enhanced, and the manufacturing cost is reduced.